‘ egfix‘s‘é; vtifififi‘ 7 “gas Tertiary Marine Pelecypods of California and Baja California Plicatulidae to Ostreidae By ELLEN JAMES MOORE 1 \ PALEONTOLOGY OF CALIFORNIA‘ AND BAJA CALIFORNIA \ l 1 U.S.GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—C A total of 68 species representing 23 genera ‘ in the families Plicatulidae, Spondylidae, Anomiidae, Limidae, Gryphaeidae, and Ostreidae ‘ are illustrated, taxonomy revised and updated, geographic and geologic ranges given, occurrence by geologic formation cited, ‘ and habitat included when it can be confidently inferred ‘ UNITED STATES GOVERNMENT PRINTIN% OFFICE, WASHINGTON : 1987 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress catalog card no. 86-600557 For sale by the Books and Open-File Reports Section, US. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 CONTENTS Page Abstract ____________________________________ C 1 Introduction _________________________________ 1 Purpose and scope ___________________________ 1 Procedure ________________________________ 1 Acknowledgments ___________________________ 4 Abbreviations ______________________________ 4 Systematics: Pelecypods—Continued from Chapter B _______ 5 Superfamily Pectinacea _______________________ 5 Family Plicatulidae _______________________ 5 Genus Plicatula ______________________ 5 Family Spondylidae _______________________ 6 Genus Spondylus ______________________ 6 Superfamily Anomiacea _______________________ 9 Family Anomiidae ________________________ 9 Genus Anomia __________________________ 9 Genus Anomia ? _________________________ 11 Genus Placunanomia ______________________ 1 1 Genus Pododesmus _______________________ 13 Superfamily Limacea _________________________ 13 Family Limidae __________________________ 13 Genus Lima _________________________ 13 Genus Acesta ________________________ 14 Genus Limaria _______________________ 16 Genus Limatula ______________________ 1 7 Genus Limea ________________________ 1 7 Genus Limea? ________________________ 17 Superfamily Ostreacea ________________________ 17 Family Gryphaeidae _______________________ 17 Subfamily Exogyrinae ___________________ 18 Genus Gryphaeostrea ________________ 18 Subfamily Pycnodonteinae ________________ 18 Genus Pycnodonte __________________ 18 Systematics: Pelecypods—Continued from Chapter B Superfamily Ostreacea—Continued Family Gryphaeidae—Continued Subfamily Pycnodonteinae—Continued Genus Pycnodonte? _________________ 020 Genus Hyotissa ____________________ 22 Genus Neopycnodonte ________________ 23 Genus Neopycnodonte? _______________ 23 Family Ostreidae _________________________ 24 Subfamily Lophinae ____________________ 24 Genus Lopha ______________________ 24 Genus Lopha? _____________________ 24 Genus Dendostrea __________________ 25 Genus Dendostrea? __________________ 25 Subfamily Ostreinae ____________________ 27 Genus Ostrea _____________________ 27 Genus Ostreola ____________________ 28 Genus Ostreola? ___________________ 29 Subfamily Ostreinae, incertae sedis __________ 29 Subfamily Crassostreinae ________________ 30 Genus Acutostrea ___________________ 3O Genus Acutostrea? __________________ 32 Genus Saccostrea ___________________ 32 Genus Striostrea ___________________ 32 Genus Striostrea? ___________________ 33 Genus Crassostrea __________________ 35 Genus Crassostrea? _________________ 38 Fossil localities _______________________________ 40 Geologic formations cited for occurrence of pelecypods _______ 41 References cited _______________________________ 42 Index ______________________________________ 4 9 ILLUSTRATIONS [Plates follow index] PLATE 1. Plicatula, Spondylus. 2—4. Spondylus, 5. Spondylus, “Spondylus”, Anemia. 6. Anomia, Placunanomia. 7—8. Anemia, Placunanomia, Lima, Pododesmus. 9. Spondylus, Limatula, Lima, Pododesmus, Acesta. 10. Lima, Limea?, Acesta, Limaria. 11. Pycnodonte, Dendostrea?. 12. Pycnodonte, Dendostrea?, Striostrea?. 13. Pycnodonte, Dendostrea?, Acutostrea. 14. Pycnodonte?, Dendostrea?, Acutostrea, 15. Pycnodonte?, Dendostrea?. 16. Hyotissa, Acutostrea, Pycnodonte?, Striostrea?, Dendostrea? 17. Lopha, Pycnodonte?. 18. Saccostrea, Pycnodonte?. 19. Gryphaeostrea, Crassostrea?, Pycnodonte? 20. Crassostrea?. 21, Pycnodonte7, Crassostrea?. 22. Crassostrea?, Striostrea?. III PLATE 23. 24. 25. 26—27. 28. 29. 30. 31. 32. 33. 34. FIGURE 1. 2. TABLES 1—10. $35,019.09”? p—A 999°.“ CONTENTS Crassostrea, Crassostrea, Crassostrea?. Striostrea?, Crassostrea?. Crassostrea, Crassostrea?, Striostrea?. Crassostrea. Crassostrea, “Ostrea”, Acutostrea, Striostrea?. Ostreola, Acutostrea, Ostrea. Dendostrea?, Ostreola?. Dendostrea?, Ostreola?, Neopycnodonte?, Acutostrea Acutostrea, Acutostrea?, Ostreola?. Ostreola?, Dendostrea?, Acutostrea. Page Map showing divisions used in California for geographic range of species of pelecypods, Plicatulidae to Ostreidae _____ C2 Map showing divisions used in Baja California peninsula for geographic range of species of pelecypods, Plicatulidae to Ostreidae __________________________________________________________ 3 TAB LE S Page Geologic and geographic distribution: Plicatula _______________________________________________________________________ C 5 Spondylus ______________________________________________________________________ 6 Anomia, Anemia? _________________________________________________________________ 9 Placunanomia, Pododesmus ___________________________________________________________ 12 Lima, Acesta, Limaria, Limatula, Limea? __________________________________________________ 14 Gryphaeostrea, Pycnodonte, Pycnodonte? ___________________________________________________ 18 Hyotissa, Neopycnodonte?, Lopha?, Dendostrea? ______________________________________________ 23 Ostrea, Ostreola, Ostreola?, “Ostrea”, Acutostrea, Acutostrea? _____________________________________ 27 Saccostrea, Striostrea ? ______________________________________________________________ 33 Crassostrea, Crassostrea? ____________________________________________________________ 36 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA TERTIARY MARINE PELECYPODS OF CALIFORNIA AND BAJA CALIFORNIA: PLICATULIDAE TO OSTREIDAE By ELLEN jAMES MOORE ABSTRACT The description of the mollusks in the Tertiary formations of Califor- nia and Baja California is continued from Chapter B. The families Plicatulidae, Spondylidae, Anomiidae, Limidae, Gryphaeidae, and Ostreidae, which represent 23 genera and 68 species, are covered in this chapter; other chapters will follow in zoologically systematic order. All the Tertiary species that were described from or are known to occur in the Californias are included, along with their original descrip- tions and their distribution by formation. The holotype is illustrated where feasible, and tables show the geologic and geographic occur- rence of the species in each genus. Of the 23 genera studied, the Gryphaeidae and Ostreidae were most in need of taxonomic revision, and only 1 of the 39 species originally assigned to Ostrea is retained in that genus. The marked response of oysters to their particular habitats causes more variation in shell character within individual species than in any other group of bivalves. The size, shape, and sculpture are all affected by substrate, by crowding, and even by the intensity of available light. The abundance and gigantic size of Crassostrea and Striostrea during Miocene time in California parallels that of the pectinids during the same time period, just prior to the well documented cooling trend that reached its nadir during the Pleistocene. This population and gigantism explosion may be related to shallow, restricted seaways fed by rivers and streams rich in nutrients, in addition to the known relationship to the temperature of the seas. INTRODUCTION PURPOSE AND SCOPE The description and illustration of the Tertiary marine mollusks of California and Baja California started in Chapter A is continued in this chapter, which treats the families Plicatulidae to Ostreidae. A total of 68 species assigned to the included families occur in the geographic study area. For convenience of reference, the figures showing the geographic divisions used for the Californias are reproduced (figs. 1, 2). PROCEDURE All Tertiary marine mollusks originally described from California and the Baja California peninsula, and all species originally described from other geographic localities but known to occur in the Tertiary of the Cal- ifornias, are included in this study. All positively identi- fied species that have been found on faunal lists are also included. In genera that are extremely rare, I have included species that are only questionably identified. In this work, species are arranged systematically fol- lowing the order of families, genera, and subgenera given in the Treatise (Moore, 1969; 1971). The order in which families are arranged and the generic and sub- generic categories have generally not been modified, except in a few cases. Most modifications made reflect either definitive papers published after publication of the Deatise or works published earlier but not cited in it. Within the systematic groups, species are arranged by geologic age, beginning with the oldest species and ending with the youngest. Some of the names of genera and subgenera adopted in this paper have not been used before for eastern Pacific Tertiary species. Brief synopses of generic and subgeneric characters are given in the appropriate places; more complete synopses will be found in the Treatise (Moore, 1969; 1971), in Keen (1971), in Hertlein and Grant (1972), and in Olsson (1961). For genera and subgenera that are not included in the Deatise, com- plete descriptions are given in the text. Distribution tables are included to show graphically the geographic and geologic distribution of species within each family. To facilitate finding a specific taxon, the species are listed alphabetically under genus and subgenus in the tables. The synonymy for each species includes the original citation and subsequent substantive references. The C1 CZ PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA I25 120' 115° I I I HUMBULDT 39“ P— Q .Q ‘ CONTRA 3’ SAN FRANCISCO 9 cos” 42” NORTHERN MIDDLE :l v: )> z —« > 4—) :u C N . 0 <9 <° ’I/ O0 MONTEREV KINGS 0 84411 0/ O 5' 0 67/5), KERN l‘“ 0 ‘> Z SANTA BARBARA 2 m I $ Santa Cruz I 34’“ _ I— . Q lsland : 3 San Miguel Island v], I 8 Santa Rosa Island __,I II I I ll ’ Santa I IlCamlina i :3 l San Nicolas Island §. II Island II I l l 0 50 100 150 200 KILOMETERS '. SAN DIEGO IMPERIAL San Clemente Island I FIGURE 1.—-Divisions used for geographic ranges of species of pelecypods, Plicatulidae to Ostreidae, reported from California. Heavy solid lines indicate no rthern,middle , and southern divisions; dashed lines within southern region divide Channel Islands area. TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE 116° IN“ 112° 110° I I I San Diego I L c A L I F o R N | A I ..‘~"—--—-- " ”“3““ ARIZONA 32° .. ‘~ \‘ Ensenada ‘\ \\ (/4, ‘ \1’50 ‘ S m Alg%:4!€s V O \‘ ~ \ z. \‘ v \ a O \‘-——-——__4 0 San Quintin 7 O ( r 30° F— ’ Rosario 4 m 't: O C 13 > 7, Isla Angel ‘ , de la Guatda O 7 O - ¢ m I O O "n Bahia ‘9 °\ C '5'“ 28° r— __ lsla Cedrosfi Sebastian ’\ Tiburon Vizt‘aino 6‘ ° 0 O \ Baht/a Tdrmla 7 — ( O «x Bahia O Conceprk’m ’9 \ 0 Laguna \\ San Ignacio ’1» 26° _ 0 I .7 m ? ... z 0 e lsla Santa Magdalena Bahia Magdalrna 24‘ __ X\ “lsla Cerralvo U 50 H10 150 200 KILUMETERS I i Cabo San Lucas FIGURE 2.—Divisions used for geographic ranges of species of pelecypods, Plicatulidae to Ostreidae, reported from Baja California peninsula. C3 C4 accuracy of identifications cited in subsequent refer- ences in the synonymy has not been verified. The type is usually that of the author of the original description or of later workers who selected a lectotype or neotype. Where the original locality description is so vague that it is of little use, the type locality is described as corrected or modified by other workers such as Keen and Bentson (1944) and the modifications given within brackets. All other localities are cited as originally described except that the formation given is that cur— rently used. Previously published supplementary descriptions and comparisons are included and I have supplemented this in the section headed “Comments”. For most descriptions, my comments are based only on examina- tion of primary type material. All available published data for each species have been included in the section on geographic and geologic age range, including that contained in faunal lists when the identification is unqualified. Age ranges have not been refined within epochs. Where a stage name the same as a formation name is used, it is placed in quotes to distinguish it from the rock unit. The divisions used here to indicate the approximate geographic range of species within California based on county distribution are northern, middle, and southern (fig. 1); the divisions for the Baja California peninsula, Norte and Sur (fig. 2) (tables 1-10). An attempt has been made to include all citations to a species that are unqualified and every geologic forma- tion in which it is reported to occur in the Californias. The assumption has been made that all identifications of species are correct unless there is strong evidence to the contrary. The stratigraphic nomenclature used herein is that of the author(s) cited and does not neces- sarily agree with that of the US. Geological Survey. The age given for the stratigraphic units follows the classi- fication of geologic time currently used by the US. Geo- logical Survey. (See “Geologic Formations Cited for Occurrence of Pelecypods” at end of paper.) Each forma- tion listed is followed by the name of the author and date of publication of the work from which it was obtained. More than one reference to a formation is given where it might be useful to the reader. The list of formations given for species occurrence should not be considered complete or necessarily accurate. Many western Amer- ican Tertiary faunas have not been monographed, and their species content is not fully known. It is hoped that the list of formational occurrence reported will serve as a framework upon which the true distribution of each species can be built. The type specimens were all photographed by Kenji Sakamoto, US. Geological Survey. Owing to the fact that the specimens photographed were borrowed from PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA other institutions, Sakamoto did not use his usual tech- nique of opaquing specimens for photography (Sakamoto, 1973). The holotype of each Tertiary species is figured if the type is extant. Holocene type specimens have not been figured; specimens considered to be of the same species by authors such as Durham (1950) and Hertlein and Grant (1972) are used for these illustra- tions, and this information is included in the plate expla- nation. ACKNOWLEDGMENTS Kiyotaka Chinzei, University of Tokyo, Japan, A. Myra Keen, Santa Rosa, Calif, and John G. Vedder, US. Geological Survey, reviewed the manuscript, and their pertinent suggestions were most helpful. Harold W Harry, Bellaire, Texas, read the section on oysters, sug- gested generic revisions based on his studies of soft part anatomy and shell characters, and furnished ecologic data for the group. The following individuals made available or loaned type material or made arrangements for photography, and I am indebted to them: Barbara A. Bedette, US. Geological Survey; Frederick J. Collier, National Museum of National History; Vickie Kohler, Museum of Comparative Zoology; Carole J. Hickman, University of California at Berkeley; Barry Roth, California Academy of Sciences; Lou Ella Saul, University of California, Los Angeles, Charles L. Powell, II, US. Geological Survey, Menlo Park, Calif, Carol C. Jones, Philadelphia Acad- emy of Sciences; Frederick R. Schram, San Diego Natu- ral History Museum; Druid Wilson, Smithsonian Institution; and Edward C. Wilson, Los Angeles County Natural History Museum. Mildred P. James made up cards for each species and its occurrences as noted on faunal lists. This was a time- consuming task, and I thank her for her patience and support. ABBREVIATIONS ANSP: The Academy of Natural Sciences of Phila— delphia, Philadelphia, Pa. BM (NH): British Museum of Natural History, London, England. CAS: California Academy of Sciences, San Francisco, Calif. LAM: Los Angeles County Museum of Natural History, California. MCZ: Harvard Museum of Comparative Zoology, Cambridge, Mass. SDNM: San Diego Natural History Museum, Califor- ma. CAS/SU: Stanford University, Stanford, Calif. [The TERTIARY MARINE PELECYPODS: Stanford University collections are now housed at the California Academy of Sciences.] SU: Stanford University, Stanford, Calif. UC: University of California, Berkeley. UCMP: University of California, Museum of Paleon- tology, Berkeley. UCR: University of California at Riverside. USGS: US. Geological Survey, Washington, DC, Cenozoic locality register. USGS M: US. Geological Survey, Menlo Park, Calif, Cenozoic locality register. USNM: National Museum of Natural History, Wash- ington, D.C. UW: University of Washington, Seattle, Wash. SYSTEMATICS: PELECYPODS—CONTINUED FROM CHAPTER B Superfamily PECTINACEA Family PLICATULIDAE Genus PLICATULA Lamarck, 1801 Subequivalve or with right valve usually more convex, cardinal area small, resilium pit acutely triangular, adductor scar in relatively pos- terior position. Subgenus PLICATULA Auricles absent or ill-defined, most species with radial sculpture and imbricating concentric lamellae; short spines common. Geographic range—Living: restricted to tropics; fossil: cos- mopolitan. Geologic range—Triassic to Holocene (table 1). Habitat—At depths from intertidal zone to 140 m in the eastern Pacific (Bernard, 1983, p. 24). Plicatula ostreiformis Stanton Plate 1, figures 1—3 Plicatula ostreiformis Stanton, 1896, p. 1038, pl. 63, figs. 5—6. TABLE l.—Geologic and geographic distribution of PLICATULIDAE AND OSTREIDAE C5 Plicatula ostreaformis Stanton. Dickerson, 1914, p. 151, pl. 9, fig. 12 [error for ostreiformis]. Original description.—— “Shell large, irregularly ovate in outline, but varying considerably in this respect; valves subequal, the right one being usually slightly convex and the left flattened or a little concave in the middle; test unusually thick; surface with obscure radiating plica- tions and irregular pits.” Syntypes.—USNM 157838. Type locality—One mile [1.6 km] southeast of Lower Lake [NE1/4, T. 12 N., R. 7 W.], Lake County, Calif. Martinez Formation, Paleocene. Supplementary description.— “An average specimen measures 52 mm. in length, 39 mm. in breadth, and 19 mm. in greatest convexity of the two valves united. “Internal casts show impressions of the characteristic hinge of Plicatula.” (Stanton, 1896, p. 1038) Geographic range—Northern California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Dickerson, 1914). Plicatula penicillata Carpenter Plate 1, figures 4, 6, 8, 9 Plicatulapenicillata Carpenter, 1857, p. 155-156. Durham, 1950, p. 69, pl. 13, figs. 2, 5. Olsson, 1961, p. 154-155. Keen, 1971, p. 94, fig. 208. Original description.— “P. t. alba, brunneo saepe tenue penicillata, elongata, haud valde costata, margine plerumque plicata; dentibus cardinalibus elongatis, rugosis, externis magnis valde extantibus; intermis angustis, ligamentum minimum tabulatum amplectentibus; cicatrice musculari subcirculari seu subovali.” Holotype.—BM(NH) Tablet 701; missing? Type locality.—Mazatlan, Mexico. Supplementary description.— “A very young valve .15 across is not plicated; a larger flat specimen on Crepidula is ribbed, but scarcely plaited at the margin: a still larger one is but very indistinctly ribbed. A swollen short specimen, grown on a spine of Murex nigritus, is rather strongly plicated; while the largest ***, grown between two folds of Chama, scarcely displays crenations, except near the hinge. The finest grown specimen displays the following characters: margin scarcely plicate, internally finely cremated on each side of the hinge: a deep hollow in each valve running up inside the umbos: central teeth (on the attached valve) joined together for more than half their height, the genus Plicatula in the eastern Pacific region [HzHolocene; P1=Pliocene; Pa=Paleocene] Species California Baja California Central or South Northern Middle Southern Norte Sur America Genus Plicatula astreiformis Stanton ............ Pa ------------------------- penicillata Carpenter ..................... Pl H spondylopsis Rochebrune ----------------------- P1 to H H 06 holding the ligament, which is extremely small, tubular, only exposed at the extremities, and running up to the umbos, though not exposed (or scarcely covered) as in Spondylus, but nearer the interior of the shell. In the free valve, the ligamental tube rises up separating the pits of the inner teeth. In this specimen the muscular scar is almost round; in another, rather oval. The valves are held together by the interlock- ing of the large rugose teeth.’ (Carpenter, 1857, p. 156) “Shell variable in size and shape from nearly circular, flattened forms to irregularly humped, elongate-ovate types, the lower valve is usually broadly attached over most of its surface. Upper valve may show a few, irregular, ill-defined riblets around the margin or the whole surface may be flat and plain or with an occasional short, hollow, spinelike elevation rising above it.” (Olsson, 1961, p. 154). Geographic range—Living: Galapagos Islands and Ecuador; fossil: Baja California Sur. Occurrence in Baja California Sun—Pliocene: Marquer Formation (Durham, 1950). Habitat—Intertidal zone (Bernard, 1983, p. 24) in rock crevices or inside dead shells (Keen, 1971). Plicatula spondylopsis Rochebrune Plate 1, figures 7, 10 Plicatula spondylopsis Rochebrune, 1895, p. 242. Hertlein, 1934a, p. 62, pl. 21, fig. 9. Durham, 1950, p. 69, pl. 15, fig. 2. Olsson, 1961, p. 155. Keen, 1971, p. 94, 96, fig. 209. Original description.— “Testa transverse ovato rotundata, crassissima, affixa; valvis radiatim costato sulcatis, costis squamis imbricatis ornatis; marginibus intense dentatis; extus sordide lilacina, intus alba.” Holotype.—In Paris Museum. Ripe locality.—Laguna des Isles de San Jose, Golfo de California. Supplementary description—“Shell roughly trigonal in shape, ornamented by coarse radial plaited sculpture, which, however, may be partially or almost wholly absent on some specimens; two hinge teeth in each valve *** Muscles scar nearer the posterior margin.” (Olsson, 1961, p. 155) Comparison—“Differs from P. penicillata by its smaller area of attachment, usually thicker, vaulted shell, and strong ribs. Some specimens of Plicatula in the US. National Museum, probably belong- ing to this species are sharply plicated and resemble P. gibbosa Lamarck of the Western Atlantic.” (Olsson, 1961, p. 155). Geographic range—Living: Golfo de California to Ecuador and Galapagos Islands; fossil: Baja California Sur. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Occurrence in Baja California Sun—Pliocene: Marquer Formation (Durham, 1950); Pleistocene: Isla Maria Magdalena (Durham, 1950). Habitat—Intertidal zone to 5 m (Bernard, 1983, p. 24). Family SPONDYLIDAE “Cemented Pectinacea lacking simple, prismatic calcite; crossed- lamellar aragonite prominent, extending well outside pallial line nearly to distal margins and covering hinge plate, which bears promi- nent dysodont teeth. Byssal notch generally present in early growth stages and lacking a ctenolium. Mantle curtains without guard tenta- cles. “The early ontogeny of the spondylid ligament is precisely like that of pectinids, with the central, lamellar portion of the resilium being continuous with the anterior and posterior outer ligaments, which continue throughout ontogeny along the straight hinge. The lateral fibrous pads originate as in the Pectinidae. The grooves, which arise late in ontogeny and in many cases become multiple, appear to be nothing more than crenulations of the resilium possibly resulting from confinement to a narrow space.” (Waller, 1978, p. 354). Geologic range—Jurassic through Holocene. Genus SPONDYLUS Linné, 1758 Well inflated, mostly with strong radial sculpture, many forms spiny or foliaceous; cardinal area of right valve large, triangular; crural teeth short, heavy, smooth, or with weakly crenulated edges. Geologic range—Jurassic through Holocene (table 2). Geographic range—Living: restricted to the tropics; fossil: cos- mopolitan. Habitat—Spondylus attaches to a rock surface by cementation of the right valve, with the exception of the species Spondylus regius Linné which is not ordinarily attached. The right valve shows great variation depending upon the shape of the object chosen for attach- ment and the size of the area of the shell attached (Dodge, 1952, p. 125). Spondylus is commonly attached to littoral boulders which are usually covered by fine growths of algae extending equally over the rock and over the shell (Purchon, 1977, p. 178-179). Spondylus carlosensis Anderson Plate 1, figure 5 Spondylus carlosensis Anderson, 1905, p. 194, pl. 13, fig. 1.Arnold, 1909 [1910], p.13, pl. 2, figs. 6, 7. Vokes, 1939, p. 57, pl. 3, figs. 10, 13. TABLE 2.—-G'eotogic and geographic distribution of the genus Spondylus in the eastern Pacific region [H=Holocene; P1e=Pleistocene; Pl=Pliocene; M=Miocene; O=Oligocene; E=Eocenel Species California Baja California Central or South Northern Middle Southern Norte Sur America Genus Spondylus bostrychites Guppy ............... M or Pl """""""" calcifer Carpenter ................. M or P1 and Ple P] to H Ple and H H cartosensis Anderson ......... E E """""""" clifl'ensis M.A. Hanna .......... E """""""" perrini Wiedey ..................... O and M O and M """""""" princeps Broderip ..................... Ple P1 to H H TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE Original description—“Shell of medium size, sub-circular or o— bliquely ovate, radially ribbed, convex; costae granulated or obscurely spinose; ears and hinge rather broad. The costae radiate in graceful sinuous lines from the beak to the margins, and occur in pairs or triplets, every second or third rib being more elevated than the others.” Holotype.—CAS 56. Type locality—West and north of Coalinga [NW1/4, sec. 35; T. 20 S., R. 14 E.], Fresno County, Calif. Domengine Formation, Eocene. Supplementary description—“The left valve figured is irregular in outline. There is a well-marked regular umbonal area of development during the period preceding attachment. The sculpture consists of irregular, sharp, round-topped ribs of varying strength, usually large ribs alternating with smaller ones, with approximately nine more prominent noded ribs subequally spaced over the surface of the valve. The ears have been broken. “The hinge shows long auricular crurae, buttressed ventrally by two ridges. The ligamental groove is long and narrow, extending to the apex; the crural sockets are subtriangular, set beneath the umbonal ends of the crurae." (Vokes, 1939, p. 57) Comparison.—“Spondylus cliffensis *** is a smaller species and appears to be characterized by the possession of a longer hinge-line.” (Vokes, 1939, p. 57). Geographic range—Middle and southern California. Geologic range—Eocene. Occurrence in California—Eocene: Avenal Sandstone (Stewart, 1946), Domengine and Tejon Formations (Vokes, 1939), and Cozy Dell Shale (Weaver and Kleinpell, 1963). Spondylus cliffensis M. A. Hanna Plate 2, figure 3 Spondylus cliffensis M. A. Hanna, 1927, p. 278, pl. 32, figs. 2, 7. Original description—“Shell small, inequilateral, subcircular, only slightly inflated; beaks not prominent or central; hinge line straight; surface distorted; ornamented by many small prominent sharp round- topped ribs of various sizes; usually large ribs alternate with smaller ones, every third to fifth large rib more prominent, some of the very large ribs appear to be noded; surface crossed by a few indistinct growth lines. Dimensions: Altitude 25.5 mm, length 29 mm.” Holotype.—UCMP 31025. Type locality.—UC 5062. San Diego County, Calif Rose Canyon Shale (Hanna, 1926), Eocene. Comparison.—Spondylus cliffensis is smaller and seems to have a longer hinge line than S. carlosensis (Vokes, 1939, p. 57). Geographic range—Southern California. Geologic range—Eocene. Occurrence in California—Eocene: Rose Canyon Shale (Hanna, 1927). Spondylus perrini Wiedey Plate 2, figures 1, 4-7; plate 9, figure 1 Pecten (Hinnites)giganteus Gray. Eldridge and Arnold, 1907, pl. 32, fig. 1. Not Pecten (Hinnites) giganteus Gray, 1825. Spondylusperrini Wiedey, 1928, p. 138, pl. 17, figs. 6, 7. Loel and Corey, 1932, p. 203, pl. 32, figs. 1a, 1b, 1c, 2. Avila and Weaver, 1969, p. 59, pl. 34, figs. 11a,11b. Spondylus inezana Wiedey, 1928, p. 139, pl. 16, figs. 2, 3. Original description—“Shell large, variable in shape, narrowly ovoid, very inequivalve, slightly inequilateral, and very strongly inf- lated. Anterior dorsal margin not long, quite straight, sharply trun- cated at the extremity, curving into the broadly rounded basal margin, which varies in the degree of curvature owing to the irregularity of C7 outline of the shell. Posterior dorsal margin short, curving slightly from its gently rounded extremity to the hinge line. Umbo of the left valve of much greater size than the umbo of the right valve. It is long, narrow, highly arched, and projected very markedly over the corre- sponding feature of the right valve. Umbo of the right valve, if elevated, is broadly inflated and quite blunt. The beaks are strongly incurved, sharp, and prominent. The sculpturing consists of about twelve or more prominent ribs, which are rendered rugose by having small spines, which evidently projected sharply forward, now broken away. Two or more smaller ribs sculpture the very wide interspaces. Incre- mental sculpture prominent. The hinge line is very short and the ears are very subdued and not prominent. The areas adjacent to the ears under the umbones in the combined valves are deeply depressed. Length, 85 mm.; breadth, 59 mm.; thickness of the combined valves, 60 mm.; the left valve projects as much as 20 mm. over the right valve in some individuals.” (perrini) “Shell very large, of variable shape, generally subcircular, ineq- uivalve to a large degree, inequilateral, and slightly to moderately inflated in most individuals. Anterior dorsal margin often long and nearly straight to broadly rounded, more sharply curved at its extremity. Basal margin broadly rounded to the posterior dorsal extremity, which is a little more sharply rounded. The posterior dorsal margin is quite broadly curved but may be straight and long. Umbones of subequal size, with the left valve possessing the more prominent umbo, which is generally moderately elevated and projected slightly over the umbo of the right valve. Beaks in most forms obscured, but apparently distant, situated in the anterior portion of the shell and not prominent. The left valve is the more strongly convex with occasional individuals possessing a nearly flat right valve. Valves sculptured by about fifteen prominent radiating ridges, which are narrow and appear to have supported numerous small spines, projecting obliquely forward. The ribs are more prominent on the central parts of the valves and less distinct toward the dorsal margins. Between the heav- ier ribs is another system of ribbing in the wide interspaces, consisting of a rather fine median rib flanked by a varying number of finer thread- like riblets, generally four or more. Concentric wavy lines of growth become very prominent on the older parts of the shell and assume the character of wavy folds in some of the old individuals. Hinge line not long; ears vary in size, projecting moderately on either side of the beaks. Length, 72 mm.; breadth, 60 mm.; thickness of the combined valves, 45 mm.” (inezana) Holotype.—SDNM 28 [SDNM 438 in original text is in error]; of S. inezana Wiedey, SDNM 29. Type locality—SDNM and SU 437. Head of Wiley Canyon [51/2, sec. 12, T. 3 N., R. 19 W., S.B. Piru quad], Ventura County Calif. Vaqueros Formation, Oligocene and Miocene; of S. inezana, the same locality. Supplementary description. —“Wiedey describes two species, S. per- rini and S. inezana, from the same locality and same bed. He states that both are very variable and that S. inezana differs in being less convex and more circular in outline. “Study of a large number of specimens from the type and other localities in the region has shown that there is but one species pres- ent—Spondylus perrini Wiedey by priority. The characters of con- vexity, valve equality, and height of umbo in the left valve are all differential in development, variability being of course due to the attached mode of habitat. It is the inequivalve variant form described by Wiedey as S. perrini, with the lower valve largest, which is usually comparatively less convex, not the reverse case as Wiedey states. “The variant described as ‘S. inezana,’ in which individual valves are more nearly equivalve owing to position of attachment, is usually much more convex (the reverse of Wiedey’s observations)" (Loel and Corey, 1932, p. 203) Geographic range—Middle and southern California. Geologic range—Oligocene and Miocene. C8 Occurrence in California—Oligocene and Miocene: Rincon Shale (Avila and Weaver, 1969) and Vaqueros Formation (Loel and Corey, 1932); Miocene: Monterey Shale (Avila and Weaver, 1969). Spondylus bostrychites Guppy Plate 2, figure 2; plate 3, figure 2; plate 9, figures 3, 9 Spondylus bostrychites Guppy, 1867, p. 176. Woodring, 1925, p. 76-77, pl. 9, figs. 5-7. G D. Hanna, 1926a, p. 477, pl. 24, figs. 3, 4. Palmer, 1938, p. 152-155, pl. 1, figs. 1, 2; pl. 2, figs. 1, 3, 5; pl. 3, figs. 1-5. Original description.—“Testa subregularis, totondata, ventricosa, margine latiusulco, valide denticulateo; extus radiatim costata, costa 5 and 6 spiniferis; area cardinali alterius valvae angustissima, alterius latiori.” Lectotype.——BM(NH) R 12833 (Palmer, 1938). Type locality—Dominican Republic, Gurabo Formation, Miocene. Supplementary description.—“ *** specimens *** show that S. bostrychites may have concentric ribs over the umbonal portion of the right valve. One of the right valve paratypes has conspicuous, con- centric ribs on the attached area. The factor of concentric lamellae is taken up in detail because authors have used the presence or absence of concentric ribs in specific determination. When concentric foliations do not occur below the point of adherence they may be present or absent and are not of specific value in such species as S. bostrychites Guppy. “Large spines project from the radiating ribs of S. bostrychites. The spines are common on the primary ribs but by no means limited to the primary ribs as has usually been described by writers. Numerous spines may be seen on secondary ribs on paratypes 3 and 4 ***. The lectotype has incipient spines on secondary ribs. The whole surface of the shell is sculptured with scaly, concentric lines giving the radiating ribs 3 lamelliform appearance. Specimens Nos. 3 and 4 have the posterior end produced in both valves. Specimen No. 5 shows a slight posterior production. Specimen No. 2 has conspicuous, concentric ribs on the umbonal region.” (Palmer, 1938, p. 152, 153). Geographic range—Southern California; Dominican Republic, Jamaica? (Palmer, 1938). Geologic range—Miocene or Pliocene. Occurrence in California—Miocene or Pliocene: Imperial Forma- tion (G D. Hanna, 1926a). Spondylus calcifer Carpenter Plate 4, figures 1, 2, 4, 5 Spondylus calcifer Carpenter, 1857, p. 152-155. G D. Hanna, 1926a, p. 477. Jordan, 1936, p. 112. Olsson, 1961, p. 153. Emerson and Hertlein, 1964, p. 350. Keen, 1971, p. 96, fig. 210. Original description.—“S. t. maxima, ponderosa, solida, plerumque orbiculari; rubropurpureo; valva superiore costis minimis aculaetis creberrimis tecta, huc et illuc costis irregularibus squamosis; squamis curtis, ad basim arcuatis, supra foliatis; valva inferiore plerumque foliata; area ligamenti magna, ligamenta haud tecto; intus subnacrea, limbo lato toto purpureo, seu nonnumquam flavesco-rubente; margine extremo creberrime et minute crenulato; dentibus validis; fossa liga- menti canalibus 2—6 parallelis, decussatis; musc. imp. suborbiculari, magna.” Syntypes.—BM(NH) Tablet 692 to 699. Type locality—Bay of Panama. Supplementary description—“Shell of medium or large size, often becomes coarse and heavy, rounded or much deformed due to fixation and growth, the valves then unsymmetrical in shape and in details of sculpture. Attachment is usually by a major part of the surface of the lower valve, often along one side of the umbonal slope, the free surface PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA covered with foliated concentrics which aid in fixation. Surface of the upper valve sculptured with numerous rows of radial spines, short or of medium length; on the middle of the disk, these spines are largest and of uniform size (not divided into sets of primary, secondary, or tertiary strength) but diminish in strength towards the sides and may be wholly absent from the anterior slope. Radial spaces between the ribs is usually wide and plainly marked with fine and coarse threads, the middle one sometimes bearing small spines.” (Olsson, 1961, p. 153) Comparison—Young shells of S. calcifer may be hard to distinguish from those of Spondylus princeps Broderip; generally the spines are more numerous and evenly distributed on S. calcifer (Keen, 1971, p. 96). Geographic range—Living: Golfo de California to Ecuador; fossil: southern California to Baja California Sur. Geologic range—Miocene or Pliocene through Holocene. Occurrence in the Californias.—Miocene or Pliocene: Imperial For- mation (G D. Hanna, 1926a); Pliocene: Almejas Formation (Jordan and Hertlein, 1926b); Pliocene and Pleistocene: Fernando Formation (J. D. Mount, written commun, 1971); Pleistocene: unnamed strata at Bahia Magdalena (Jordan and Hertlein, 1926b). Habitat.—At a depth of 2-55 min the eastern Pacific (Bernard, 1983, p. 27). Spondylus princeps Broderip Plate 3, figures 1, 3-10; plate 4, figures 3, 6; plate 5, figure 6 Spondylus princeps Broderip, 1833, p. 4. Hertlein and Strong, 1946, p. 62— 63. Hertlein, 1957, p. 66-67. Spondylusprincepsprinceps Broderip. Olsson, 1961, p. 152, pl. 22, figs. 4, 8; pl. 86, figs. 1, 1a. Keen, 1971, p. 96, fig. 211. Spondylus crassisquama Lamarck of authors; not Lamarck, 1819. Spondylus victoriae Sowerby. Durham, 1950, p. 68, pl. 15, fig. 3; not Spondylus victoriae Sowerby, 1859. Original description.—“Spond. testa rotundata, 6-costata, rubra spinosa, spinis lingulatis, latis; costis interstitialibus 5 spinosis, spinis brevioribus; intus alba, limbo lato profunde plicato, rubro: long. 5%, alt. 5, lat. 3 poll. (spinis haud inclusis).” Holotype.—BM(NH). Type locality—Isla la Plata, Ecuador. Found attached to coral rocks at the depth of 17 fathoms. Supplementary description—“Shell usually regular in shape, the valves seldom showing much distortion, the attachment area usually small. Valves not strongly convex. Sculpture of crowded, or close-set, short or medium-length, spikelike spines. Primary and secondary spines set in six rows, the tertiary in pairs of two in the space between the primary and central secondary (four in the larger interspaces between the primaries). Inner marginal band wide and deeply colored. *** The subspecies is readily distinguished by its crowded, spikelike spines, showing no open spaces between them.” (Olsson, 1961, p. 152) Geographic range—Living: Laguna de Scammon to Negritos, Peru, and Golfo de California; fossil: Baja California Sur. Geologic range—Pliocene through Holocene. Occurrence in Baja California Sun—Pliocene: Almejas (Minch and others, 1976) and San Marcos (Durham, 1950) Formations; Pleistocene: unnamed strata on Isla Coronados (Emerson and Hertlein, 1964). Habitat—At depth of 2-40 In (Bernard, 1983, p. 27). “Spondylus estrellanus Conrad” Plate 5, figure 2 Spondylus estrallensis Conrad, 1857a, p. 315 [error for estrellanus]. Spondylus estrellanus Conrad, 1857c, p. 191, pl. 1, fig. 3. TERTIARY MARINE PELECYPODS: Original description.—“Obtusely ovate; both valves ventricose; ribs 17, not very prominent, rounded, rugose; valves with radiation striae.” Type—A specimen (USNM 13312) is in the U.S. National Museum type collection labelled, presumably by Conrad, from Estrella Valley, Calif, and catalogued in 1884 (pl. 5, fig. 2). It does not compare well with the specimen figured by Conrad (1857c, pl. 1, fig. 3) that is missing and presumed lost. This specimen (USNM 13312) is not a Spondylus; it is Lyropecten estrellanus (Conrad, 1857a). Conrad did not describe the hinge area of Lyropecten estrellanus in his original description, and I assume that the hinge was not exposed. However, the specimen he described as Spondylus estrellanus did have the hinge exposed, and he described the hinge as having lateral tubercles or teeth that are prominent, conical, and very robust (1857c, p. 191). Perhaps the strong crura led him to believe that the species was Spondylus rather than Lyropecten. The original illustration of Spondylus estrellanus (Con- rad, 1857c, pl. 1, fig. 3), which resembles Lyropecten estrellanus some- what, shows none of the characters of Spondylus. All available evidence points to the conclusion that Conrad did not have a Spon- dylus in his collections from Estrella Valley and mistakenly identified some specimens of Lyropecten estrellanus as Spondylus. The descrip- tion of “Pallium” estrellanus is on page 313 and that of “Spondylus” estrellanus on page 315 (Conrad, 1857a), thus giving page priority to Lyropecten estrellanus. Type locality—Estrella Valley (T. 26 S., R. 13 E., San Luis Obispo County], Calif. Santa Margarita Formation, Miocene. Superfamily ANOMIACEA Family ANOMIIDAE Genus ANOMIA Linné, 1758 Shell thin, partially attached, foramen in right valve, left valve with three muscle scars on central area. The left (upper) valve of Anemia has one large and two small muscle impressions; the same valve of Pododesmus has one large and one small muscle impression. Geologic range—Jurassic to Holocene (table 3). Geographic range-Cosmopolitan, except not in the Arctic and Antarctic. Habitat.—“The species of this genus are attached to rocks, shells or other objects and often acquire sculpture corresponding to that of the object to which they are attached. Often only upper valves are found *** as fossils, because those become loose and are washed away, whereas the lower valve remains attached *** the byssal plug of PLICATULIDAE AND OSTREIDAE 09 members of this genus apparently corrodes surfaces to which it is attached and as a result the shell often lies sunk into a pit of its own making.” (Hertlein and Grant, 1972, p. 223). The animals arrange themselves in the plane of least resistance, thus indicating the direction of strongest current. (Jackson, 1890, p. 354). Intertidal zone to 130 m in the eastern Pacific (Bernard, 1983, p. 27). Anemia inomatus (Gabb) Plate 6, figure 2; plate 7, figure 3 Placunanomia inornata Gabb, 1864, p. 217, pl. 32, figs. 288, 288a. Arnold, 1909 [1910], p. 108, pl. 3, figs. 1, 10. Arnold and Anderson, 1910, p. 70, pl. 25, figs. 1, 10. Anderson and Hanna, 1925, p. 190. “Placunanomia” inornata Gabb. Stewart, 1930, p. 66, pl. 8, fig. 4. Pododesmus (Monia) inornatus (Gabb). Vokes, 1939, p. 57-58, pl. 3, figs. 6, 7, 9, 11. Original description—“Shell thin, irregular, inequivalve; upper valve convex, usually narrowest near the beaks, broad towards the base; hinge-margin thickened; surface marked by fine radiating lines; hinge-line but little, if at all, thickened; foramen small, bordered on one side by a thickened margin.” Holotype.—Missing and presumed lost. ANSP 4442 is here desig- nated the lectotype (Stewart, 1930, p. 66, pl. 8, fig. 4). Type locality.———Corral Hollow [T. 3 or 4 S., R. 3 E., Tesla quadrangle, Alameda County], Calif. Domengine Formation, Eocene. Supplementary description.—“Recent collections from Corral Hol- low have furnished abundant material representing Gabb’s species. Among the specimens is a right valve through the byssal notch of which projects a portion of a somewhat calcified byssus. There is a single prominent muscle-scar on the disk. The valve embraces but does not join about the foramen, which is bordered posteriorly by the ventral buttress of the posterior ligamental platform. The right valve is flattened; the left moderately to well inflated. The umbos are promi- nent, and there is a well developed cardinal area. “The Domengine specimens show a range in coarseness of sculptur- ing which fully embraces both Gabb’s and Hanna’s species. The inte- rior of Anomia mcgoniglensis is not sufficiently well known to allow determination of its true generic position.” (Vokes, 1939, p. 58) “The cardinal area is wide and the ligamental attachment was presumably beneath this platform in the umbos.” (Stewart, 1930, p. 66, pl. 8, fig. 4) Comparison—According to Vokes (1939, p. 58) the sculptural varia- tion of A. inornatus is sufficient to include A. mcgoniglensis, based on TABLE 3.—Gealogic and geographic distribution of the genus Anomia in the eastern Pacific region [H=Holocene; P1=P1iocene; M=Miocene; O=Oligocene; E=Eocene] Species Oregon California Baja California Central or South Northern Middle Southern Norte Sur America Genus Anemia hannai Wiedey ................................... O and M """""""""" inconspicua Clark .............................. M? """""""""" inornatus Gabb .................................. E """""""""" peruviana Orbigny. """"" H M or P1 to H H P1 to H H subcostata Conrad ............................. M and P1 M or P1 """""""" uaquerosensis Loel and Corey .......... O and M O and M """""""" Genus Anomia? mcgoniglensis M.A. Hanna .......... E """"" E """""""" C10 that character alone, but the lack of a well preserved interior of A. mcgoniglensis leaves its generic allocation in doubt. Geographic range—Middle California. Geologic range—Eocene. Occurrence in California.—Domengine Formation (Stewart, 1930). Anemia hannai Wiedey Plate 5, figures 4, 5 Anemia hannai Wiedey, 1929b, p. 280-281, pl. 31, fig. 1. Original description—“Shell quite large, not thick, subovoid, rather convex near beak, flattened toward basal margin, more pointed and angular in umbonal area; surface sculptured by about ten coarse, low, irregularly radiating ribs, which tend to split; interior surface irregular, deep in vicinity of beak; ligamental pit apparently broad, deep, but not high. Height, 67 mm.; breadth, 57 mm.; thickness, single valve, 18 mm.” Heletype.—CAS/SU 514. Type locality—8U 449. Monterey County, Calif. Vaqueros Forma— tion, Oligocene and Miocene. Comparison—“The fewer ribs and larger form serve to distinguish this new species from Anemia peruviana d’Orbigny, living in the Gulf of California. A. hannai is more triangular and less gibbose than the average form of A. subcostata Conrad of the Carrizo Creek beds, lower Pliocene in age, ofImperial County, California.” (Wiedey, 1929b, p. 281) Anemia hannai is higher in proportion to length than A. uaquerosensis. The two species are so similar otherwise that addi- tional material may very well show them to be conspecific. Geographic range—Middle California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros For- mation (Wiedey, 1929b). Anemia vaquerosensis Loel and Corey Plate 5, figure 7; plate 6, figures 9, l2 Anemia uaquerosensis Loel and Corey, 1932, p. 203-204, pl. 33, figs. 1a, 1b, 2a, 2b, 3, 4. Original description—“Shell thin, medium size, subtrigonal, longer than high, inequilateral, of a silvery~nacreous platy material; left valve moderately inflate [inflated] flattening outwardly, umbone [umbo] strongly inflate with inconspicuous beak twisted to posterior; distinct notch in posterior dorsal margin, rest of periphery irregularly crenulate though evenly rounded. Shell is folded or fluted from umbone to ventral margin posterior to middle and ornamented by about eight narrow irregular and discontinuous crenulations which become stronger and divergent outwardly, annulations very irregular. Hinge margin is thickened, strongly incurving, roughened; interior of shell uneven, ligament pit covered directly under beak, triangular in shape. Muscle scar area is above the center and inclined anteriorly; major byssal adductor scars in a vertical line, minor byssal scar below and to anterior, below which is the smallest byssal scar. Right (attached, or lower) valve not found whole. Length, 57 mm.; height, 50 mm.” Holotype.——UCMP 31758. Type locality.—UC A—336. Ventura County, Calif. Vaqueros Forma- tion, Oligocene and Miocene. Supplementary description. —“Other specimens are three times the size of the one described. The species is very irregular in shape because of its habit of attached growth. In many specimens the outline and inflation of beak is almost brachiopod-like, usually with deep radial folds as well as a varying number of plications (usually 6-8). ***It is easily identifiable by its thin, silvery shell even when incomplete and PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA should be recognized as one of the best of Vaqueros index fossils. Anemia vaquerosensis, n. sp. has frequently been reported as ‘Ostrea sp. ’ ” (Loel and Corey, 1932, p. 204) Comparison—‘AnOmia vaquerosensis is distinct from any of the few described North American species.” (Loel and Corey, 1932, p. 204) See also Anemia hannai Wiedey described above. Geographic range—Middle and southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros For- mation (Eaton and others, 1941; Durham, 1968; Dickinson, 1969; Squires and Fritsche, 1978). Anemia inconspicua Clark Plate 6, figure 8 Anemia inconspicua Clark, 1918, p. 133, pl. 13, figs. 19-20. Original description—“Shell small, thin, subcircular and some- what variable in outline; beaks inconspicuous, subcentral in position, on some specimens slightly twisted but on others not; left valve con- vex; right valve flat, with a large byssal notch. Surface smooth except for rather heavy, irregular incremental lines. Muscle area, as seen on left valve, with one fairly large, distinct scar which is slightly posterior to the beak; other scars indistinct. Hinge line very thin, with a small, deeply sunken resilifer.” Holotype.—UCMP11205. Type locality.—UC 1131. Contra Costa County, Calif. San Ramon Sandstone, Miocene(?). Comparison—“This species appears to be quite distinct from any- thing described from the West Coast. Possibly the form that is nearest isAnomia linatula [limatula l Dall, from which it differs in being much smaller, in the hinge not being so heavy, and in lacking the faint radiating lines seen on the latter.” (Clark, 1918, p. 133) Geographic range—Middle California. Geologic range.—Miocene(?). Occurrence in California.—Miocene(?): San Ramon Sandstone (Clark,1918). Anemia subcostata Conrad Plate 6, figures 7, 10, 13; plate 7, figure 5; plate 8, figure 1 Anemia subcostata Conrad, 1855, p. 267. Conrad, 1857b, pl. 5, fig. 34. Conrad, 1857c, p. 161, pl. 19, figs. 1a, 1b. GD. Hanna, 1926a, p. 460, pl. 23, figs. 3-5. Grant and Gale, 1931, p. 241. Original description—“Obtusely ovate from base to back; lower valve thick, with interrupted somewhat tubercular radii; upper valve thin, radii obsolete or wanting. Height, 11/2 in.” Lectotype.—USNM 1865 is here designated the lectotype (pl. 6, fig. 7). The holotype was cited previously (Keen and Bentson, 1944, p. 25) as USNM 13345a. Two specimens are numbered USNM 13345a (pl. 6, figs. 10, 13) but neither of these specimens agrees with Conrad’s two illustrations. The lectotype agrees very well with the specimen illus- trated by Conrad (1857b, pl. 5, fig. 34), but not with the other specimen illustrated by him (Conrad, 1857c, pl. 19, figs. 1a, 1b). The line drawing (Conrad, 1857b, pl. 5, fig. 34) shows the same breaks in the shell and the same radial sculpture as is seen on the lectotype. Type locality.—[Carrizo Creek], Colorado Desert, [Imperial County], Calif. Imperial Formation, Miocene or Pliocene. Supplementary description.—“Obtusely ovate, rather thick; umbo of larger valve ventricose; hinge thickened, surface of the valve obtusely undulated concentrically, and marked with waved, wrinkled, interrupted ribs, much raised, except towards the base, where they are larger and somewhat tuberculiform; upper valve entire, or with TERTIARY MARINE PELECYPODS: obsolete radii towards the base.” (Conrad, 1857e, p. 161, pl. 19, figs. 1a, 1b) “Among this large number [100] there is exhibited great variation in shape, sculpture and weight. The radial sculpture ranges from very decided ribs to none at all ***” (G D. Hanna, 1926a, p. 460) Geographic range—Southern California. Geologic range—Miocene and Pliocene. Occurrence in California—Miocene or Pliocene: Imperial Forma- tion (Grant and Gale, 1931); Miocene and Pliocene: Etchegoin Forma- tion (Smith, 1912). Anomia peruviana Orbigny Plate 6, figures 1, 4, 6 Anemia peruviana Orbigny, 1846, p. 673. Grant and Gale, 1931, p. 240, pl. 12, figs. 2, 5. Olsson, 1961, p. 177, pl. 24, figs. 2-2f. Hertlein and Grant, 1972, p. 223-224, pl. 40, fig. 2; pl. 41, fig. 8. Keen, 1971, p. 101, fig. 223. Original description.—“Coquille presque arrondie, un peu carree plus longue que large, tres-deprimée, marquee en dessus de quelques indices de cotes rayonmantes peu prononcees, nombreuses. Sa couleur est verdatre tres-pale ou rosée; son interieur est verdatre, le ligament entierement vert. La valve inferieure a ses bords desunis sur une grande largeur. Diametre, 33 millimetres." Holotype.—BM(NH). Type locality.—Paita, Peru. Holocene. Supplementary description—“Recent specimens of Anomia peru- viana vary in shape and in sculpture. They may be smooth exteriorly or they may bear well developed radial ribs occasionally bearing very short spines. Exterior sculpture of the shell of Anomia may simulate that of the object to which it is attached. Partly because of the multi- plicity of forms resulting from such situs this species has received a number of names in the literature. The following are generally consid- ered to be synonyms: Anemia hamillus Gray, A. larbas Gray, A. alectus Gray, A. lampe Gray, A. pacilus Gray, Anomya’ simplex Mabille.” (Hertlein and Grant, 1972, p. 224) Geographic range—Living: middle California to Paita, Peru; fossil: southern California to Ecuador. Geologic range—Miocene or Pliocene through Holocene. Occurrence in the Californias.—Miocene or Pliocene: Imperial For- mation (C. L. Powell, oral commun, 1983) Pliocene: Almejas (Minch and others, 1976) and Infierno (McFall, 1968) Formations; Pliocene and Pleistocene: Fernando (Soper and Grant, 1932) and Saugus (Waterfall, 1929) Formations; Pleistocene: unnamed strata in southern California (Valentine, 1960), and in Baja California Sur (Emerson, 1980). Habitat—“Common on clam shells and rock off exposed beaches along the open coast.” (McLean, 1978, p. 71) “*** lives in quiet bays where it is attached to rocks or to empty shells by a byssus which extends through a notch in the lower valve. The pearly upper valves, which may be white, green or yellow, are often found upon the beaches where the species occurs. The lower valves often are not found, or occur but sparsely among empty shells. This is probably a result of the method of attachment.” (Hertlein and Grant, 1972, p. 224). Intertidal zone to 130 m (Bernard, 1983, p. 27). Genus ANOMIA? Anomia? mcgoniglensis M. A. Hanna Plate 5, figures 1, 3 Anomia mcgoniglensis M. A. Hanna, 1927, p. 278, pl. 31, figs. 1, 2, 5, 7. Turner, 1938, p. 46, pl. 6, figs. 4-6. Weaver, 1942, p. 100, pl. 22, figs. 4, 5. PLICATULIDAE AND OSTREIDAE C11 Original description—“Shell of medium size and thickness, only moderately inflated, slightly distorted, shape varying from ovate to elongate, of irregular outline; surface striated by rough, prominent, concentric growth lines and scales; whole surface radially sculptured by many ribs; radial ribs are rounded, slightly nodulose where crossed by growth lines, vary in direction due to distortion of the shell, sepa- rated by regularly concave shallow interspaces which vary in size about like the ribs; surface of the inner margin irregular, smooth; muscle scar very large, central, and just below the beak. Dimensions.—- Cotype No. 31011: Altitude 29 mm., length 34 mm., diameter 9 mm. Cotype 31012: Altitude 30 mm., length 28 mm., dia- meter 9 mm.” Syntypes.—UCMP 31009-31012. Type locality. —UC 3981. San Diego County, Calif. Delmar Forma- tion, Eocene. Comparison—Anemia? mcgoniglensis differs from A. inornata (Gabb) in the coarser sculpturing, both concentric and radial. (M. A. Hanna, 1927, p. 278) Vokes (1939, p. 58) said that the range in coarseness of sculpture of Anomia inornatus (Gabb) is sufficient to include A.? mcgoniglensis, but the lack of well preserved interiors made generic allocation uncer- tain. Geographic range—Oregon; southern California. Geologic range. —Eocene. Occurrence in California—Eocene: Delmar Formation (M. A. Hanna, 1927; Givens and Kennedy, 1976). Genus PLACUNANOMIA Broderip, 1832 With about three strong radial plications; byssal foramen obsolete in adult; interior with one retractor scar. Geographic range—Eastern and western North America; western Central America. Geologic range—Miocene through Holocene (table 4). Placunanomia granti Hertlein Plate 6, figure 3 Placunanomia granti Hertlein, 1928, p. 148, pl. 23, figs. 7—9. Loel and Corey, 1932, p. 204, pl. 33, figs. 5, 6a, 6b. Original description—“Shell moderately small, subcircular in out- line, inequivalve, compressed. Upper valve slightly convex; surface irregularly wrinkled. Lower valve slightly concave, sculpture similar to right. A short depressed groove is present on the beak. Altitude, 34 mm.; length, 29 mm.” Holotype.—CAS 4139. Type locality—GAS 1150. Santa Barbara County, Calif. Vaqueros Formation, Oligocene and Miocene. Comparison—“This small and rather irregularly faintly plicated species does not resemble closely any other west coast Placunanomia. It does not show the radial striations of P. californica Arnold and is smaller and more corrugated than P. hannibali Jordan and Hertlein.” (Hertlein, 1928, p. 148) Geographic range—Southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Rincon Shale (Avila and Weaver, 1969) and Vaqueros Formation (Hertlein, 1928). Placunanomia caliform'ca Arnold Plate 6, figures 5, 11 Placunanomia californica Arnold, 1909, p. 75-76, pl. 24, figs. 2, 2a, 3. Grant and Gale, 1931, p. 243. Adegoke, 1969, p. 106, pl. 10, fig. 4. C12 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA TABLE 4.4—Geologic and geographic distribution of the genera Placunanomia and Pododesmus in the eastern Pacific region lH=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; O=Oligocenel Species Alaska British Washington Oregon California Baja California Columbia Northern Middle Southern Norte Sur Genus Placunanomia californica Arnold ................................................. M and Pl Pl ---------- granti Hertlein ................................................ O and M ---------- hannibali Jordan and Hertlein ............................................. p1 Genus Pododesmus Subgenus Mania macroschiema (Deshayes) ......... H H H H H M to H P1 to H Ple to H H Original description—“Shell averaging about 65 millimeters in length, subcircular in outline, inequivale [inequivalve], compressed. Right valve irregular, somewhat convex, the surface sculptured by numerous small, thread-like, rugose, radiating ridges and several laminae of growth; byssal foramen, though closed, leaves an oblique semicovered pit near the beak; two strong elevated rough crests—the auricular crura—diverge from the beak at a very acute angle; imme— diately behind the auricular crura is the broadly V-shaped scar of the byssal muscle, on each side of which is a deeply impressed groove, and in the middle of which is an oblique V—shaped pit which was once connected with the external pit forming the byssal foramen; adductor scar subcircular to irregular and equal in diameter to over one-third the length of shell. Left valve flat to slightly concave; surface sculpture similar to but less prominent than that of right valve; a broad V- shaped socket, into which the crura of the right valve fits, occupies the area below the beaks; adductor scar same as in right valve. “Dimensions—Altitude 66 mm.; latitude 60 mm.; diameter of both valves 33 together; 17 mm.” Holotype.—USNM 165546 (right valve). Type locality.—USGS 4715. Kern County, Calif. Etchegoin Forma- tion, Miocene and Pliocene. “This rare shell, of which the type, paratype, and a fragment are the only specimens so far known, is characterized by the elevated auricular crura of the right valve and V-shaped socket of the left. Its external sculpture is quite similar to certain specimens of Pododesmus (Mania) macroschisma Deshayes, found Recent and fos- sil on the Pacific coast. The only other member of the genus Placunanomia on the Pacific coast is the Recent P. cumingi Reeve, of the Recent Gulf of California province, which is characterized by one or two very strong plications. P. californica is thinner and more nearly circular in outline than P. plicata ’I‘uomey and Holmes, of the upper Miocene of the Carolinas; it also has radial sculpture, which is lacking in the latter.” (Arnold, 1909, p. 75-76) Comparison—“This rare species differs from P. cumingii in the presence of radial riblets and the very low, almost obsolete plications. P. hannibali Jordan and Hertlein is very closely related, but has finer radial sculpture and the byssal scar is not sub-triangular as in Arnold’s species.” (Grant and Gale, 1931, p. 243) Geographic range—Middle and southern California. Geologic range—Miocene and Pliocene. Occurrence in California.——Miocene and Pliocene: Etchegoin For- mation (Arnold, 1909); Pliocene: San Joaquin Formation (Adegoke, 1969). Placunanomia hannibali Jordan and Hertlein Plate 7, figures 2, 6, 7; plate 8, figures 2, 5 Placunanomia hannibali Jordan and Hertlein, 1926b, p. 443-444, pl. 28, figs. 2-4. Grant and Gale, 1931, p. 243. Smith, 1984, p. 206, pl. 205, figs. 2, 3. Original description—“Shell large, thin, subcircular to suboval in outline, usually very flat, compressed and more or less regular in growth; most specimens with no evidence of radial plication but a few more or less profoundly, radially plicate; surface sculptured by con- centric growth lines, and by very fine, wavy, minutely prickly, radial striations. Right valve slightly arched; byssal foramen closed or nearly so, but leaving an elongate oblique semi-triangular pit near the beak, which almost communicates with the interior; auricular crura very strong, diverging from the beak at an acute angle varying somewhat in different specimens, Left valve flat or concave, never convex as is the right; without byssal foramen, but usually broken slightly at the beak; interiorly with two strong ribs radiating from the umbo, but fitting outside of the auricular crura,” and hence diverging at a somewhat greater angle. Length 114 mm.; width 95 mm.; thickness 15 mm.” Holotype.—CAS 2110. Type locality—OAS 945. Baja California Sur. Almejas Formation, Pliocene. Comparison.—“Placunanomia hannibali is related to P. californica Arnold *** but is distinguished by having a generally flatter and more regular shell with very fine rather than heavy radial sculpture. P. cumingii Broderip, from the recent fauna of western Mexico and the upper Pliocene of Maria Madre Island is very strongly radially plicate, and lacks all radial sculpture. P. hannibali is most nearly related to P. lithobleta Dall, of the Miocene of the Caribbean region, but seems to attain a larger size than that species, and to be fitted with larger and heavier auricular crura.” (Jordan and Hertlein, 1926b, p. 443—444) “This species is closely related to P. californica Arnold, but *** appears to attain a larger size and the byssal scar does not have the subtriangular shape of the type of californica. ” (Grant and Gale, 1931, p. 243) Geographic range—Baja California Sur. Geologic range—Pliocene. Occurrence in Baja California Sun—Pliocene: Almejas (Minch and others, 1976), Gloria (Wilson and Rocha, 1955), and Infierno (Wilson and Rocha, 1955) Formations. TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE Genus PODODESMUS Philippi, 1837 Sculpture of irregular corrugations; shell attached, byssal foramen large, small, or even obsolete; left valve with one large and radially striate byssal retractor scar. Pododesmus “***differs from Placunanomia in possessing an open byssal foramen in the lower valve, although small or sealed over in the type species, and in lacking large, well developed cardinal crura. It differs from Anomia in possessing only one muscle impression (in addition to the byssal impression), rather than two.” (Hertlein and Grant, 1972, p. 225) Geographic range—North and South America, Europe, Australia, and Japan. Geologic range.—Eocene(?); Oligocene through Holocene (table 4). Subgenus MONIA Gray, 1850 Byssal retractor scar large; foramen of moderate to large size. The shell of Mania differs from Pododesmus (Pododesmus) “in pos- sessing a large byssal opening and in that the large perforation of the lower valve only slightly embraces the large thin plug.” (Hertlein and Grant, 1972, p. 225) Geographic range—New Zealand, North America, and Europe. Geologic range—Oligocene through Holocene. Pododesmus (Mania) macroschisma (Deshayes) Plate 7, figure 4; plate 8, figures 4, 7; plate 9, figure 7 Anomia macrochisma Deshayes, 1839, p. 359. (Specific name later emended by Carpenter, fide Keen, 1971, p. 103). Pododesmus (Mania) macroschisma (Deshayes). Arnold, 1903, p. 116-117. Hertlein and Grant, 1972, p, 225-226, pl. 40, fig. 3; pl. 41, figs. 9, 12,13. Monia macroschisma Deshayes. Arnold, 1909, p. 134, pl. 14, fig. 1. Vedder and Moore, 1976, pl. 1, fig. 3. Pododesmus macroschisma (Deshayes). Grant and Gale, 1931, p. 241-242, pl. 12, figs. 3, 4a, 4b. Adegoke, 1969, p. 106. Placunanomia cepio Gray, 1850. Kern, 1973, p. 74. Pododesmus (Mania) cepio (Gray, 1850). Keen, 1971, p. 103, fig. 227. Pododesmus cepio (Gray, 1850). McLean, 1978, p. 71-72, fig. 393. ?Pododesmus newcombei Clark and Arnold, 1923, p. 141, pl. 21, figs. 3-6. Original description.——“Testa irregulariter ovata, inaequivalvi, albo-viridula, irregulariter plicata; valvaii superiore convexa, inferiore plana, suprene late perforata, foramine integro, marginibus acutis plicatis, valvis intus submargaritaceis, superiore mac- ulamagna satirata viridi ornata.” (macroschisma) “Scars 2, far apart; upper very large, ovate, longitudinal, central; lower smaller, oblong, oblique, rather behind the upper *** Plug large, flat, broad. Notch large wide.” (cepio) Holotype.—Location unknown; of cepio, BM(NH). Type locality.— “Kamtschatka;” of cepio, California. Supplementary description—“The thickness of the shell and the development of coarse or fine radial sculpture (occasionally obsolete) varies greatly depending upon the situs.” (Hertlein and Grant, 1972, p. 226) Authors have most recently separated P. (M .) macroschisma as the Pododesmus living in the north and western Pacific and P. (M. ) cepio as the southern species. Pododesmus cepio has been distinguished from P. macroschisma chiefly on the basis of a thinner shell, sculpture, and a larger byssal foramen. Hertlein and Grant (1972, p. 226) stated that “the variation in a large series is so great that there appear to be no 013 criteria to rely upon for separating the shells *** unless certain forms are arbitrarily selected to represent various species. *** Burch, after studying a large series of specimens of Pododesmus from Puget Sound and from Monterey, California, stated that he could find no basis for the recognition of more than one species." On the basis of these statements, I have synonymized P. cepio. Geographic range—Living: Japan; Alaska to Baja California Sur; fossil: middle California to Baja California Norte. Geologic range—Miocene to Holocene. Occurrence in the Californias.—Miocene: Pancho Rico (Durham and Addicott, 1965) and Santa Margarita (Addicott and Vedder, 1963) Formations; Miocene and Pliocene: Etchegoin (Adegoke, 1969) and Towsley (Kern, 1973) Formations; Pliocene: Careaga Sandstone (Wood- ring and Bramlette, 1950), Niguel (J. G. Vedder, written commun, 1978) and San Diego (Hertlein and Grant, 1972) Formations and unnamed Pliocene strata on San Clemente Island (Vedder and Moore, 1976); Pliocene or Pleistocene: Fernando (Arnold, 1907c) and Potato Harbor (Weaver and Meyer, 1969) Formations; Pliocene and Pleistocene: Merced (Arnold, 1909; Glen, 1959), Pico (Waterfall, 1929), and Saugus (Kew, 1924) Formations; Pleistocene: San Pedro Formation (Eaton, 1928), Timms Point Silt Member, San Pedro Formation (A. Clark, 1931), and unnamed strata in Southern California and in Baja California Norte (Valentine, 1960). Habitat—Common on shells of abalone, submerged reefs, break- water rocks, and inside dead shells (Smith and Gordon, 1948, p. 170; McLean, 1978, p. 72). Intertidal to 90 m (Bernard, 1983, p. 27, 28). Superfamily LIMACEA Family LIMIDAE Genus LIMA Bruguiere, 1797 Subtrigonal, higher than long, with rather short hinge margin; auricles relatively well differentiated, anterior one slightly the smaller; anterior umbonal ridge not strongly marked; inflation only moderate; gapes of valve margins only slight; hinge edentulous or with weak denticles near ends of hinge margin; ornament of scaly radial ribs. “Many species are superficially alike and the external ornamenta— tion may vary with habitat. Useful distinguishing characters are found in the comparative height of the umbones and the length of the cardinal area just below the beaks.” (Bernard, 1979, p. 31) Geographic range—Cosmopolitan. Geologic range—Triassic to Holocene (table 5). Habitat. —“*** most often found in deep and cold waters. Individu- als are able to move and sometimes swim, by pulsating the extremely long tentacular fringe of the mantle edges. More usually, species are byssally attached, often in ‘nest’ of matted byssal threads that may serve as a protection for the exposed tissues and delicate shell.” (Ber- nard, 1979, p. 31) According to Purchon (1977, p. 149) Lima lima is byssally attached under boulders and has a heavily built shell whereas Lima fragilis, which can swim, has a small, fragile shell. Thus, the thickness of the shell of fossil limids may indicate whether they lived byssally attached or were free moving. Subgenus LIMA Lima (Lima) vedderi Moore Plate 10, figures 1, 3 Lima vedderi Moore, 1977, p. 277, figs. 2, 6, 7, 9, 10. C14 Original description—“The shell of Lima vedderi is moderately thick, and the preserved part bears 20 prominent slightly rounded ribs that are separated by rounded interspaces about half as wide as the ribs of the anterior and posterior margins, but as wide as the ribs on the central part of the shell, Assuming a normal positioning of the beaks, the holotype is about 45 mm high and 50 mm long. Distinctive bulbous nodes are preserved along the entire length of the surface of the ribs; no part of the ribs is smooth The nodes are massive and shaped like very shallow cups with their dorsal surfaces convex and smooth and their ventral surfaces concave. The nodes are about evenly spaced; the distance between the mid—points ranges from 2.2 to 2.8 mm. Although the general configuration of the nodes is regular, some nodes are more nearly semispherical and thicker than others. No minor sculpture similar to that on L. uedderi has been noted on any described Lima, nor, for that matter, on any other pelecypod genus. The uniqueness of the sculpture makes identification of even small fragments feasible. The outline, shape, and ribbing of L. vedderi are sufficient to make assignment to the genus Lima reasonably certain. Holocene specimens of Lima tetrica Gould from Baja California, the only similar northeast Pacific species, *** differs from L. vedderi in sculpture; the ribs on L. tetrica bear spines and lamellae rather than nodes.” Holotype.——USNM 240060. Type locality.—USGS M3220. Orange County, Calif. Monterey Shale, Miocene. Geographic range—Southern California. Geologic range—Miocene. Occurrence in California—Miocene: Monterey (Moore, 1977) and Santa Margarita (Addicott and others, 1978) Formations and unnamed Miocene strata on San Clemente Island (Moore, 1977). Genus ACESTA H. and A. Adams, 1858 Large, thin-shelled, ovate, inequilateral, with moderate byssal gape; anterior umbonal ridge ill defined; anterior auricle reduced; PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA ligament pit broad, curved. Cardinal area narrower than that of Lima s.s. Geologic range—Jurassic through Holocene (table 5). Geographic range—Cosmopolitan. Habitat.—Living in cold water or at great depths (to 2,550 m). Subgenus ACESTA Sculpture of superficial, rather irregular, radiating riblets that are moreystrongly developed on anterior and posterior portions of valves. Geographic range—Living: California to Chile. Hertlein (1952) described a new species ofAcesta collected off California between 1260 and 1465 m from Mulberry Seamount, thus extending the northern range of the genus. The scarcity of collections from deep water no doubt directly relates to the known geographic distribution of living Acesta as well as fossil species. (Vokes, 1963, p. 75) Acesta (Acesta) multiradiata (Gabb) Plate 10, figures 5, 8 Lima multiradiata Gabb, 1869, p. 201-202, pl. 33, fig. 101. Stanton, 1896, p. 1038, pl. 63, figs. 7, 8. Dickerson, 1914, p. 151, pl. 8, fig. 1. Stewart, 1930, p. 125, text fig. 2. Original description.—“Shell (right valve) large, oblique, com- pressed subelliptical; anterior side forming a regular curve to the middle of the base, very slightly sinuous above, under the ear; pos- terior portion of the basal margin much more narrowly rounded than in advance, uniting by a broad curve above, with the posterior side, the upper half of which seems to have been nearly straight; the anterior ear seems to have been long and narrow. Surface convex a little behind the middle, the anterior slope being broad and nearly flat; the entire surface covered by very numerous, slightly wavy, somewhat irregular, TABLE 5).—Geologic and geographic distribution of the genera Lima, Acesta, Limaria, Limatula, and Limea? in the eastern Pacific region [H=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; E=Eocene; Pa=Paleocene] Species California Baja California Central or South Northern Middle Southern Norte Sur America Genus Lima Subgenus Lima vedderi Moore ...................................... M """""""" Genus Acesta Subgenus Acesta hamlini (Dall) ....................................... P1 """""""" multiradiala (Gabb) ....................... Pa Pa E Pa """"" Subgenus Plicacesta haseltinei (Dickerson) ....................... Pa Pa """""""" Genus Limaria Subgenus Limaria clarki (Nelson) ..................................... Pa """""""" hemphilli (Hertlein and Strong) ........ H M to H P18 and H H H orcutti (Hertlein and Grant) .............. Pl """""""" Genus Limatula afl'. subauriculata (Montagu) .................. Pl """""""" Genus Limea? Subgenus Isolimea? claytonensis (Dickerson) ................... Pa """""""""" TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE radiating ribs of small size, and with narrow interspaces; on the younger portion of the shell, the spaces between the ribs are mere impressed lines, the ribs being convex; near the base, however, the ribs become proportionally smaller, the spaces are wider than the ribs, and are concave, and the whole are crossed by minute subsquamose lines of growth.” ‘ Holotype.—MCZ 15016. Type locality. —N ear Lower Lake Village [NE1/4, sec. 11, T. 12 N ., R. 7 W.], Lake County, Calif. Martinez Formation, Paleocene. Supplementary description—“The holotype *** is very poorly pre- served. The right margin is unknown and the left dorsal region has been worn away while the ventral margin is entirely broken away. Unfortunately, the growth lines are not well exposed so that it is impossible to obtain the true outline of the shell. It has been possible to expose part of the left side, showing that the shell is more convex than the original figure suggests. The radial ribs are irregular and some- what wavy.” (Stewart, 1930, p. 125) Geographic range.—Northern California to Baja California N orte. Geologic range—Paleocene and Eocene. Occurrence in the Californias.—Paleocene: Martinez (Weaver, 1905; Dickerson, 1914) and Sepultura(?) (Gardner in Darton, 1921) Formations; Eocene: Tejon Formation (Stanton, 1896; Arnold, 1906). Acesta (Acesta) hamlim' (Dall) Plate 10, figures 4, 7 Lima hamlini Dall, 1900, p. 16. Arnold, 1907a, p. 527. Dall, 1925, p. 18, pl. 29, fig. 6. Lima (Acesta) hamlini Dall. Woodring, 1938, p, 47-49, pl. 8, figs. 5, 7, 10, 11. Original description—“Several specimens, more or less crushed, of a large Lima are among the forms collected. This species belongs to the general type of Lima excavata Fabr, L. goliath Sby, etc., and reaches to a length of four and a half inches. The valves are brilliantly polished, and in the middle part unsculptured, the anterior and pos- terior thirds are finely radially grooved with shallow grooves of which the outer slopes are less steep than the inner; the incremental lines, obsolete elsewhere, appear in the channel of the grooves and cross striate it here and there, giving the effect of obsolete punctation. I may add that close to the impressed area of the shell there are two or three coarser, deeper radial grooves. The species differs from the South Pacific and all other forms of its group known to me in its much finer and more delicate sculpture and brilliant polish. I await more perfect specimens before trying to figure it, but would propose the name of Lima hamlini for the species in honor of Mr. Homer Hamlin C. E., Asst. City Engineer of Los Angeles, who is much interested in the geology and paleontology of the region, and has made valuable studies of the southern California Tertiary. The specimen in hand was kindly forwarded for examination by Dr. R. E. C. Stearns.” Holotype.—USNM 495186. Type locality.—USGS 3426. Los Angeles County, Calif. Fernando Formation, Pliocene and Pleistocene (from the Pliocene part of the Fernando Formation, John G. Vedder, written commun, 1983). Supplementary description—“A giant Lima allied to the modern Panamanian agassizii. Depressed area at anterior end and posterior auricle sculptured with relatively strong radial ribs that are more closely spaced toward the center of the shell, the interspaces being gradually transformed into narrow grooves, microscopically punctu- ated by concentric threads. On some specimens subdued grooves con- tinue over the central part of the shell, except in the umbonal region, but in most specimens they are absent on a central area of varying width.” (Woodring, 1938, p. 47). Comparison—Acesta hamlini is higher in proportion to length than Acesta mori (Hertlein), a species living off central California (Hertlein, 1952, p. 379). Cl5 Geographic range—Southern California. Geologic range—Pliocene. Occurrence in California—Pliocene: upper part of Capistrano (Vedder, 1972) and lower part of Fernando (Arnold, 1907c; Woodring, 1938) Formations. Subgenus PLICACESTA Vokes, 1963 Radial ribs strong on the plicate shells, not exclusively surficial as on Acesta, and characteristically they are larger on the middle of the valves than on the valve margins. Cardinal area and ligamental pit similar to Acesta; relatively thin to very thick shelled. Geologic range—Eocene through Holocene (table 5). Geographic range—Living: Japan and southern California; fossil: Asia, California, and Washington. Habitat.—90 to 185 in, Japan; 455-550 In, southern California. Acesta (Plicacesta) haseltinei (Dickerson) Plate 9, figure 10; plate 10, figures 10, ll Lima(?) haseltinei Dickerson, 1914, p. 126-127, pl. 8, fig. 2; pl. 9, fig. 11. “Lima” haseltinei Dickerson. Woodring in Hoots 1931, p. 92. Lima perrini Waring, 1914, p. 782-783. Waring, 1917, p. 76-77, pl. 10, figs. 1, 1a, 2. Original description—“Shell large, slightly oblique, nearly equi- valve, moderately convex; beak prominent, pointed, anterior, prosogy— rate; hinge, edentulous, long, straight; ears not markedly set off from rest of shell, the posterior one being the larger; anterior end broadly rounded; posterior, slightly truncated; ventral margin, arcuate; deco- ration consists of numerous squarish radial ribs with very narrow interspaces.” (haseltinei) “This giant circular lima has a thick shell with nacreous, and outer prismatic layer. The diameter is about 160 mm. The umbones are small and the cardinal margin slopes gradually to the posterior where it becomes rounded and grades into the circular margin below. The beaks are slightly excavated in front, and the margin slopes at a 35- degree angle into the rounded anterior margin. The hinge is very thick and has a deep wedge-shaped ligament pit sloping from the interior edge of the shell to the exterior edge at the anterior end of the hinge line. A single large sub-posterior muscle impression marks the inte- rior of the shell. The surface is ornamented by many fine radiating lines, and the prismatic shell layer gives the surface a silken appearance. It belongs to the subgenus Acesta.”(perrini) Holotype.—UCMP 11676; of perrini CAS/SU 303. Type locality.—UC 1540, Contra Costa County, Calif. Martinez For- mation Paleocene; of perrini, Simi Hills [1.6 km N. 68° W of Hill 2150, southwest of Santa Susana, Camulos quadrangle], Ventura County, Calif. Santa Susana Formation, Paleocene (Zinsmeister, 1983). Dickerson described Acesta haseltinei in May, 1914, and Waring described Acesta perrini in November-December, 1914. Subsequently, Waring (1917, p. 77) believed the two species to be distinct, although he did say that when more specimens were found of each this might be disproven. Because neither specimen is complete, the original outline of each can be misconceived, but on the basis of the holotypes, I can find no characters to separate the two species. It is unfortunate that the specific name haseltinei precedes perrini by a few months as the holotype of perrini is much better preserved. Both A. haseltinei and A. perrini have very thick shells; the thick shells may have been a characteristic of fossil representatives of the subgenus Plicacesta and may indicate that they were byssally attached. Geographic range—Middle and southern California. Geologic range. —Paleocene. 016 Occurrence in California—Paleocene: Martinez (Dickerson, 1914; Waring, 1914) and Santa Susana (Zinsmeister, 1983) Formations. Genus LIMARIA Link, 1807 Shell medium-sized, ovate, auricles small, subequal; radial ribs fine, not scaly. Promantellum Iredale differs but little from Limaria, but the valves of Promantellum may be more widely gaping. Submantellum differs from Limaria in the greater inflation of the valves and the lack of any posterior gape. (Hertlein and Grant, 1972, p. 215). Geologic range—Eocene through Holocene (table 5). Geographic range—Cosmopolitan. Habitat. —Species of this genus live today in temperate and tropical waters (Hertlein and Grant, 1972, p. 215). Subgenus LIMARIA Somewhat oblique, rather strongly inflated with wide posterior gape; narrow radial riblets. Geologic range—Miocene to Holocene. Geographic range—Cosmopolitan. Limaria (Limaria) clarki (Nelson) Plate 10, figure 6 Lima(?) clarki Nelson, 1925, p. 407, pl. 49, fig. 2. Original description—“Shell small, moderately oblique, ovate, compressed; beak inconspicuous. Posterior dorsal margin straight; anterior margin slightly convex, rounding evenly into ventral margin; ventral margin rounded, with decrease in curvature toward posterior extremity; character of posterior end unknown. Anterior ear small; posterior ear unknown. Surface of shell with 20 or more rounded radial ribs which are widest spaced in midportion of shell and indis- tinct toward each margin, spacing uneven in posterior third of shell. Greatest length of shell in type specimen, 12 mm; width, 8.3 mm. “The type for this species is a cast from which a small portion of the posterior end has been broken.” Holotype.—UCMP 30494. Type locality—U0 3752. Ventura County, Calif. Martinez Forma- tion, Paleocene. Comparison.—“Lima(?) clarki can be distinguished from L.(?) claytonensis Dickerson by its obliqueness and finer ribbing. It resem- bles L. packardi Weaver and Palmer, from which it can be dis- tinguished by its greater elongation and more widely spaced ribbing.” (Nelson, 1925, p.407) Geographic range—Southern California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Nelson, 1925). Limaria (Limaria) hemphilli (Hertlein and Strong) Plate 7, figure 1; plate 8, figures 3, 6, 8 Lima (Limaria) hemphilli Hertlein and Strong, 1946, p. 66-67, pl. 1, figs. 3, 4. Lima hemphilli Hertlein and Strong. Kern, 1973, p. 74. Original description—“Shell obliquely elliptical equivalve, in- equilateral, moderately convex, broadly gaping especially along the anterior dorsal margin, posteriorly narrowly gaping hinge short, anterior ear the larger, pointed and beneath which a notch is present; the maximum width of the anterior margin is above the middle of the shell; between the widest portion and the hinge the margin shows two PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA vague angulations; ventral margin elliptical, posterior margin very gently rounded; the anterior umbonal slope of the valves is gentle, the posterior slope is rather abrupt; valves ornamented by fine irregular radial ribs which are crossed by very fine imbricating lirae; anterior and posterior submargins smooth. Height 23 mm., length 16.4 mm., convexity (both valves) approximately 12 mm.” Syntypes.—CAS 9174, 9174A. Type locality—GAS 5955. San Diego, Calif. Holocene. Supplementary description—“The shell gapes a little more on the anterior than on the posterior side.” (Keen, 1971, p. 98) Comparison—Lima orcutti somewhat resembles L. hemphilli, but it has fewer, coarser, more widely spaced ribs; the hinge plate is relatively broader; and the posterior ear is much less acutely pointed (Hertlein and Grant, 1972, p. 215). Geographic range—Living: Monterey Bay, California to Acapulco, Mexico; fossil: southern California to Baja California Norte. Geologic range—Miocene to Holocene. Occurrence in California—Miocene and Pliocene: Towsley Forma— tion (Kern, 1973); Pleistocene: Palos Verdes Sandstone and San Pedro Sand (Arnold, 1903); unnamed strata in southern California (Valen- tine, 1956; Kanakoff and Emerson, 1959) and unnamed strata in Baja California N orte (Valentine and Rowland, 1969). Habitat.—On rock bottoms, 15 to 100 m (Bernard, 1983, p. 22). In swimming they carry the hinge behind, in the manner of Pecten (Baily, 1950, p. 112). Limaria (Limaria) orcutti Hertlein and Grant Plate 9, figures 4-6, 8 Lima (Limaria) orcutti Hertlein and Grant, 1972, p. 215, pl. 35, fig. 11; pl. 49 36, figs. 2-5; pl. 57, fig. 10. Original description—“Right valve, shell obliquely elliptical in out- line, inequilateral, moderately convex; greatest length (anterior-pos- terior) about halfway between beak and ventral margin, gaping along the posterior dorsal margin; hinge short, oblique, the posterior ear pointed, a shallow sinus immediately below it; the anterior margin nearly straight above, but below it is gently rounded into the ventral margin, the outline of the posterior and ventral margin forms a broad arc; anterior umbonal slope rather steep, the posterior slope rather gentle; the valves are sculptured with about 35 to 40 fine, radial riblets, some vaguely paired, all separated by wider interspaces, ribs and interspaces widest on medial portion of the valve, the whole crossed by fine imbricating lines of growth; hinge elongately tri- angular, with a broad shallow, triangular ligamental pit, a triangular pit under the posterior ear, a shallow depression under the anterior one; the interior smooth, in some places the external ribbing is visible. Dimensions of holotype: Height (beak to ventral margin) 43 mm, length approximately 35.5 mm (posterior side imperfect), convexity (left valve) approximately 9.6 mm.” Holotype.—LAM 4509. Ripe locality. —LAM 3056. San Diego County, Calif. San Diego For- mation, Pliocene. Comparison—“This new species bears a general resemblance to Lima hemphilli Hertlein and Strong which now lives in adjacent waters but the new species has fewer, coarser, more widely spaced ribs, the greatest length of the valves (anterior-posterior) is at a point about midway between the beak and the ventral margin rather than above the middle, the hinge plate is relatively broader and the posterior ear is much less acutely pointed. “The general features of the hinge are more like that of Lima orbignyi Lamy, but the shell of the new species is much more elon~ gated, less inflated and the valves gape posteriorly. “The general outline of this new species is somewhat like that of Lima auaua Dall, Bartsch, and Rehder, from Hawaii, but the character of the ribbing appears to be quite different.” (Hertlein and Grant, 1972) TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE 017 Geographic range—Southern California. Geologic range—Pliocene. Occurrence in California—Pliocene: Niguel (J.G. Vedder, written commun., 1983) and San Diego (Hertlein and Grant, 1972) Formations. Genus LIMATULA Wood, 1839 Small, oval, strongly inflated; auricles small, subequal; margins not gaping; hinge edentulous; sculpture of fine radial riblets, most con- spicuous toward center of valves and absent from posterior end. Geologic range—Triassic through Holocene (table 5). Geographic range—Cosmopolitan. Habitat.——-Most living species in the eastern Pacific are found at depths of 10-350 m, but one species is found as deep as 2,200 m (Bernard, 1983, p. 23). Limatula aff. L. subauriculata (Montagu) Plate 9, figure 2 Limatula aff. subauriculata (Montagu). Woodring, 1938, p. 49, pl. 8, fig. 6. Although not positively identified, this species is included because it is the only known fossil representative of Limatula in the Californias. It is described by Woodring (1938) as follows: “A small moderately elongate valve represents a species of Lim- atula. The sculpture consists of fine radial ribs, slightly roughened by microscopic concentric threads. Two median ribs are heavier than the others and modify the interior outline. On the interior of the lower part of the shell, where the exterior is missing, a narrow midrib lies between the heavy ribs. “This species is probably the Recent form known as Lima (Lim- atula) subauriculata (Montagu). Recent shells attain a height of 16.4 millimeters and a length of 10.4 millimeters. They have one to three relatively heavy median ribs that are differentiated by strong inter- spaces on the interior, even though the ribs are not conspicuously differentiated on the exterior, a characteristic feature of Limatula shown by the fossil.” Geographic range—Southern California. Geologic range—Pliocene. Occurrence in California—Pliocene: lower part of Fernando For- mation (Woodring, 1938). Genus LIMEA Bronn, 1831 Small; cardinal area narrow; hinge with series of short denticles on either side. Geographic range—Cosmopolitan. Geologic range—Triassic through Holocene (table 5). Subgenus ISOLIMEA Iredale, 1929 Suborbicular; sculpture of strong radial ribs with wide interspaces. Geographic range—Australia; California(?). Geologic range. —Holocene; Paleocene(?). Genus LIMEA? Subgenus ISOLIMEA? Limea? (Isoh'mea?) claytonensis (Dickerson) Plate 10, figures 2, 9 Lima(?) claytonensis Dickerson, 1914, p. 126, pl. 7, figs. 9a, 9b. Original description—“Shell inflated, with radial sculpture; rounded and almost symmetrical. Ratio of length to height about .65 to 1. Beak prominent, acute, and in some specimens compressed. Hinge line short and straight with about twelve small striations perpen— dicular to hinge line. These striations may be plications within the shell wall, revealed by th [the] breaking away of the inner shell layer. Area, narrowly elliptical and central. Basal margin, rounded. Ribs—— about thirteen in number—are acute-angled and beaded; the inter- spaces are the same in width as the ribs.” Syntypes.—UCMP 11720,11721. Type locality.—UC 1592. Contra Costa County, Calif. Martinez For- mation, Paleocene. Dickerson said that he had four specimens all from shale 30 m above the base of the Martinez Formation at the type locality. Geographic range—Middle California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Dickerson, 1914). Superfamily OSTREACEA Stenzel’s (1971) classification, in his scholarly volume on the oysters, is generally followed and I have relied heavily upon his work. Revi- sions reflect subsequent studies of the anatomy and shell characters of oysters by Harold W. Harry (1981, 1983; written commun., 1983, 1984). In the Tertiary of the Californias, 8 genera are represented by 40 species. Only three of these genera have been used by other workers for Tertiary species of oysters in the eastern Pacific. As noted by Stenzel (1971, p. N1095), classification of oysters at the generic level seems extraordinarily difficult and open to divergent opinions. For example, Woodring (1982, p. 607), who based his classification on that of Stenzel’s (1971), assigned one Tertiary species of oyster from the La Boca Formation, early Miocene, Panama, to “Hyotissa”, and he said that this species, “Hyotissa” tryoni (Gabb), was by no means a typical Hyotissa but might be a link between Pycnodonte and Hyotissa. Harry (in Harry and Dockery, 1983) described two vesicular species of oysters from the Oligocene in Mississippi, and he said that they did not fit well in any of the four subgenera of pycnodontine oysters recognized by Stenzel(1971). Harry (in Harry and Dockery, 1983) said that the three subfamilies of Ostreidae are more sharply differentiated from each other and from the Pycnodonteinae by the anatomy of their flesh, reproductive habits, and environmental preference than by the characteristics of the highly variable shells. The classification used here for eastern Pacific Tertiary oysters is preliminary. Future work on large suites of oysters from strat- igraphically controlled sections, and study of variation within large collections of single living species, will improve and refine the classi- fications suggested by me and also improve the utility of oysters as a tool in correlation. The oysters as a group show a great range of variability within a single species. Among factors causing variation are the substratum to which they are attached, the toppling over of specimens as the shell grows and becomes too heavy for a small, light-weight object to which it has attached, the crowding of individuals versus uncrowding, and even whether the shell grew in sunlight or in shade (Stenzel, 1971, p. N1019). Taking these factors into consideration, it is unwise to propose new specific or subspecific names for oysters based on one or a few specimens, especially if another species of oyster assigned to the same genus has already been described from the same stratigraphic horizon. Family GRYPHAEIDAE Muscle scar subcircular. Posterior adductor muscle orbicular in cross section and placed closer to hinge than to opposite valve margin, ventral border of its insertion on left valve sometimes elevated above general surface of valve. Valves highly unequal in most genera to subequal in others. Geologic range—Triassic to Holocene. 018 Habitat—Most genera never form true oyster reefs in which con- specific individuals grow mainly on one another. Subfamily EXOGYRINAE Chomata commonly present, varied; commissural shelf variable, often well defined; chalky deposits not vesicular; umbo of left valve inflated, opisthogyrous, coiled in several planes, right valve flat or nearly so; posterior bourrelet (posteriormost of three divisions of liga- mental area) much reduced, commonly merely a narrow ridge. Genus GRYPHAEOSTREA Conrad, 1865 Left valve highly convex and capacious; deep umbonal cavity over- hung by hinge plate; anterior wall of left valve spirally curved and rising up obliquely or vertically from substratum; angular to spoon- shaped shelly claspers growing out periodically from growth squamae of left valve to provide additional attachments. Right valve flat; outline oval to spatulate or triangular; growth squamae simple and spaced regularly apart starting close to umbo. Right valve considerably smaller than left valve, leaving wide (as much as 0.7 cm) margin on left valve uncovered in bivalved fossil specimens. Geographic range—Worldwide. Geologic range—Cretaceous to Miocene (table 6). Gryphaeostrea aviculiformis (Anderson) Plate 19, figures 1, 2, 6 Ostrea auiculiformis Anderson, 1905, p.194-195, pl. 13, figs. 3-5. Arnold, 1909, p. 50, pl. 2, fig. 12. Vokes, 1939, p. 55. Original description—“Shell small, very inequivalve, quadrate, oblique, laminated; inferior valve convex and strongly arched; supe- rior valve thin, often concave, and sharply laminated in thin concentric folds; hinge broad and somewhat straight. The surface of the convex valve is marked only by concentric lines of growth. The margin is more or less ragged or irregular.” Holotype.—CAS 21. The type was recovered after the San Francisco fire of 1906 but was considerably broken (Vokes, 1939, p. 55). PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Type locality—West and north of Coalinga [NW 1/4, sec. 35, T. 20 S., R. 14 E., Fresno County], California. Domengine Formation, Eocene. Supplementary description—“The upper valve *** was strongly laminated, with laminae which were approximately one eighth of an inch apart.” (Vokes, 1939, p. 55) Comments.—The anterior portion of the left valve is auricular and has a terebratuloid sinus. The right valve is operculiform with evenly spaced, thick laminae made up of prismatic shell layers. Geographic range—Middle California. Geologic range—Eocene. Occurrence in California.—Eocene: Domeng'ine Formation (Weaver, 1949) and Avenal Sandstone (Vokes, 1939). Subfamily PYCNODONTEINAE Commissural shelf usually well defined, delimited proximally by circumferential curb. Chomata generally present, vermiculate near ligament; divisions of ligamental area of equal size; shell vescicular. Geologic range—Cretaceous to Holocene. Genus PYCNODONTE Fischer de Waldheim, 1835 Subgenus PYCNODONTE Left valve umbo rising barely above long straight dorsal margin. Auricles present; outline subcircular to semicircular. Radial ribs absent to low, short, and gently undulatory; no. well-defined radial riblets. Geographic range—Cosmopolitan. Geologic range—Cretaceous to Pleistocene (table 6). Pycnodonte (Pycnodonte) ynezana (Loel and Corey) Plate 11, figures 1, 3, 4, 6 Ostrea eldridgei Arnold. Arnold and Anderson, 1907, pl. 16, fig. 2; not pl. 18, figs. 6a, 6b (=0. eldridgei). Not Ostrea eldridgei Arnold, 1907a. Ostrea eldridgei (Arnold) var. ynezana Loel and Corey, 1932, p. 188-189, pl. 11, fig. 3; pl. 12, figs. 1a-1c; pl. 13, figs. 1, 2a, 2b. TABLE 6.—Geologic and geographic distribution of the genera Gryphaeostrea and Pycnodonte in the eastern Pacific region [PIezPleistocene; P1=Pliocene; M=Miocene; O=Oligocene; E=Eocenel Species California Baja California Central or South Northern Middle Southern Norte Sur America. Genus Gryphaeostrea aviculiformis (Anderson) ............. E """""""""" Genus Pycnodonte Subgenus Pycnodonte erici (Hertlein) ............................ M to Ple P1 P1 P1? gnezana (Loel and Corey) ........ O and M O and M """""""" Genus Pycnodonte'!‘ Subgenus Pycnodonte? heermanni (Conrad) .................. M or Pl P1 P1 ””” howelli (Wiedey) .......... O and M """""""" loeli (Hertlein) ............. O and M M M """ wiedeyi (Hertlein) ....................... O and M """""""" Subgenus Crenostrea? eldridgei (Arnold) .................... O and M O and M """ M """ stewarti (M.A. Hanna) ............... E """""""" TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE Ostrea eldridgeiynezana Loel and Corey. Addicott, 1965, p. 0104, fig. 3f. Crassostrea eldridgei ynezana (Loel and Corey). Addicott, 1973, p. 27, pl. 2, 57 figs. 2, 10. Squires and Fritsche, 1978, p. 19, pl. 3, fig. 5. Original description—“Shell medium, moderately thin; beaks twisted posteriorly; left or lower valve moderately convex, obliquely ovate, irregularly crenulate shell layers smoothly appressed except where protruded as plicated edges; beak pointed; posteriorly extended, margin thin; upper valve concave and foliated. Interior of left valve deep, muscle scar round, central; ligament pit tapering, rounded; upper valve interior convexo-concave with lateral ridges and flat, wide margins, dorsally truncate with deep, round ligament pit. Height, 115 mm.; length, 103 mm.; diameter (thickness through both valves), 40 mm.” Holotype.—UCMP 31745. Type locality. —UC A-317. At west end of hill that is poorly defined on the topographic map about 0.8 km northwest of Rancho Atascoso house. 1.9 km S 80° E from 603-ft bench mark on road, Santa Barbara County, Calif. Vaqueros Formation, Oligocene and Miocene. Supplementary description—“Specimens of Crassostrea eldridgei ynezana are characterized by their relatively thin valves, the left being moderately convex and somewhat larger than the right. The largest specimen is about 100 mm in height. During an early stage of growth the axis of the valve undergoes a gradual rotation through about 45°, the result being posteriorly situated beaks and, on many specimens, a subquadrate outline.” (Addicott, 1973, p. 27) Comparison—“This variety of Ostrea eldridgei is gradational in all characters to O. eldridgei Arnold ***.It is characterized by its com- parative thinness of valves, lesser convexity of the lower valve and usual crenulation of the margins in a peculiar curtain-like (ruffle) effect. In many specimens the convex valve exhibits strong develop- ment of these crenulations, especially toward the margins. The umbones are often blunt or truncate.” (Loel and Corey, 1932, p. 190) “This species is similar to Crassostrea sookensis (Clark and Arnold, 1923, p. 138, pl. 17, figs. 1, 2) from the early Miocene(?) Sooke Formation of southern Vancouver Island, British Columbia. The northern species has a thicker shell in general and a less quadrate outline than spec- imens of C. eldridgei ynezana, but the holotype is too poorly preserved to determine possible relationships confidently.” (Addicott, 1973, p. 27) “The species is differentiated from O. howelli by the presence of low, fluted corrugations on the shell, in place of the larger, higher, more angular ribs of O. howelli.” (Squires and Fritsche, 1978) Comments—Although no vesicular shell structure was seen on P. ynezana, it is placed in Pycnodonte because it has a long straight hinge line, the dorsal margin is produced into a wing, and the interior of the right valve has a prominent commissural shelf and its exterior bears a few radial gashes. Geographic range—Middle and southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene: Wygal Sandstone Member, Temblor Formation (Addicott, 1973); Oligocene and Miocene: Vaqueros Formation (Bereskin and Edwards, 1969; Addicott, 1965; Squires and Fritsche, 1978); Miocene: Jewett Sand (Addicott, 1965). Pycnodonte (Pycnodonte) erici (Hertlein) Plate 12, figures 1, 4, 7, 8 Ostrea tayloriana Gabb. Jordan and Hertlein, 1926b, p. 428, pl. 33, fig. 3. Not Ostrea tayloriana Gabb, 1869. Ostrea erici Hertlein, 1929, p. 295. Durham, 1950, p. 59, pl. 4, fig. 2. Woodring in Woodring and Bramlette,1950, p. 85, pl. 8, figs. 17,18; pl. 9, figs. 1, 3, 4. Hertlein and Grant, 1972, p. 217-218, pl. 38, figs. 4, 6, 8, 9. Original description—“Shell moderately thick; sub-oval in outline; beaks sub-terminal; ligament pits sub-triangular. Right valve moder- Cl9 ately convex, shell slopes obliquely from the umbones to the anterior margin, smooth except for projecting edges of shell lamellae; margins of shell rather thin. Left valve moderately heavy, ovate in outline, slightly concave; edges of shell layers give a rather rough appearance to the shell, otherwise without ornament. Height, 94 mm.; width, 71 mm.; thickness, 36 mm.” Holotype.—CAS 2094. Type locality—Mouth of large arroyo northwest of Mesa de Ele- fante, Laguna Scammon [Laguna Ojo de Liebre, fide Woodring, 1950, in Woodring and Bramlette, 1950, p. 85], Baja California Sur. Almejas Formation, Pliocene. Supplementary description—“This species is sculptured with lamellae of varying strength. The umbonal part of the shell is thick and composed of numerous shell lamellae. On the attached (left) valve the outer lamellae form a more or less distinct ‘wing’ adjoining the attachment area. The ligamental groove is narrow and gradually tapering. The inner margin below the ligament area is smooth on large shells and smooth or faintly denticulate on small shells.” (Wood- ring in Woodring and Bramlette, 1950, p. 85) “Shell moderately large, elongately to roundly trigonal, sometimes slightly expanded posteriorly; lower valve arched, right (upper) valve flat, both valves composed of rather coarse overlapping shell laminae; ligamental pit on both valves elongately trigonal, rather small for the size of the shell; hinge plate at end of pit rounded and very slightly overhanging a shallow cavity; a small flat-topped indentation, corre— sponding to the lines of growth, occurs on each side of the ligamental pit; interior of shell smooth, large adductor impression rounded to semi-lunar, situated on the posterior side dorsally a little over one half the distance from the ventral margin to to the beak; body cavity often bounded on each side by smooth, steep walls beyond which the shell tapers to a thin edge; margins smooth, no denticles present.” (Hertlein and Grant, 1972, p. 217-218) Comparison—“No similar Recent species is known in California or adjoining areas.” (Woodring in Woodring and Bramlette, 1950, p. 85) Comments.—The left valve is suboval in outline and the anterior dorsal margin is produced into a wing, with the shell layers folded and projecting upward. The exterior of the left valve is smooth except for paper-thin extensions of the shell laminae that are most noticeable at the margins of the shell. The interior of the left valve body cavity is bounded by a steep shelf posteriorly near the dorsal margin and a less prominent shelf in the same position anteriorly. Vesicular shell struc- ture is visible on the ventral side where the shell is broken or worn. The right valve is ovate, convex near the dorsal margin and concave near the ventral. The exterior of the right valve is smooth except for radial gashes and imbricated shell lamellae, thinner at the ventral margin and showing thick (as much as 3 mm) vesicular layers where broken near the dorsal margin. Vesicular shell structure is characteristic of the Pycnodonteinae and, on the basis of the prominent commissural shelf, auricle, con— centric puckers, and radial gashes, this species is assigned to Pycno— donte. Pycnodonte erici, which closely resembles P. ynezana, differs in that the shell is thicker on P. ynezana and markedly produced at the posterior ventral margin. The left valve of the holotype of P. ynezana has worn, thick extensions of the shell lamellae that probably were more spoon-shaped than hyote. Geographic range—Southern California to Baja California Sur; Mexico? (Hertlein and Grant, 1972, p. 218) Geologic range.—-Miocene to Pleistocene. Occurrence in the Californias.—Miocene and Pliocene: Sisquoc For- mation (Woodring and Bramlette, 1950); Pliocene: Almejas (Minch and others, 1976; Smith, 1984), Boleo (Wilson and Rocha, 1955), Carmen (Durham, 1950), Cebada Member of the Careaga Sandstone and Foxen Mudstone (Woodring and Bramlette, 1950), Gloria (Wilson and Rocha, 1955), Purisima (Cummings and others, 1962), and Niguel (Vedder, 1972) Formations; Pliocene and Pleistocene: Fernando Formation (Willett, 1946). C20 Genus PYCNODONTEP Subgenus PYCNODONTE? The placement of the species that follow in Pycnodonte? is not based on objective criteria. On the basis of shell characters, it does not seem possible at this time to determine critically where Pycnodonte ends and Hyotissa begins. Harold W. Harry (written commun., 1984) sug- gested that these thick plicate species might be assigned to Hyotissa ?. Woodring (1982, p. 607), in describing “Hyotissa” tryoni (Gabb), said that: “This species is by no means a typical Hyotissa but may be a connecting link between Pycnodonte and H yotissa. ” On the basis of the specimens that I have examined, I prefer at the present time to assign the species under discussion to Pycnodonte? (Pycnodonte ?). The vari- ability of O. heermanni in collections from the Imperial Formation, for example, is considerable; some specimens resemble Hyotissa and oth- ers Pycnodonte, but more seem to me to resemble Pycnodonte. Pycnodonte? (Pycnodonte?) howelli (Wiedey) Plate 14, figures 1, 3, 5, 7 Ostrea howelli Wiedey, 1928, p. 135-136, pl. 15, figs. 1, 2. Squires and Fritsche, 1978, p. 19, pl. 2, figs. 1-6; pl. 3, figs. 3, 4. Original description. —“Shell of moderate size. Variable outline, but most forms exhibit a subcircular to subovoid contour. It is very ineq- uivalve and is seldom equilateral. The left valve is the more convex and thick-shelled. In some specimens the dorsal portion is the narrower part of the shell while the basal end is often wider and more broadly rounded. Umbo of the left valve is found in some individuals to pre- serve the small subcircular shell of the young stages, showing about six prominent, radiating, irregular ribs as the principal sculpturing. Sculpturing on the adult consists of about six prominently elevated, radiating ridges, separated by narrower channels. Ribs show a tend— ency to divide at different stages of growth in some specimens. Strong, concentric, incremental growth lines become very coarse toward the basal margin. The interior is smooth with the muscle impression very deep, round, and situated in the posterior portion near the dorsal margin. The ligamental pit is robust, moderately long, roundly and deeply channeled. Length from the margin at the hinge to the distant periphery 90 mm.; breadth, about 60 mm.; thickness of a single valve, 40 mm.” Syntypes.——SDNM 26; CAS 2981, 2982; CAS/SU 422 [missing; Keen and Bentson, 1944]. Type locality. —SU and SDNM 446. Ventura County, Calif. Vaqueros Formation, Oligocene and Miocene. Comparison—“This new species of Ostrea may not be easily con- fused with any other known fossil forms because of its very distinctive characteristics. It bears external similarity of outline most closely to Ostrea vespertina Conrad, but the latter species is much thinner shelled. This new form also possesses a much more powerful hinge and greater arching of the shell than Conrad’s species. It shows a slight similarity to O. titan Conrad and O. titan Conrad, var. corrugata Nomland. The latter may be separated by its broader resilial pit, relatively smaller muscle impression, and much less prominent sculp- ture of the shell than found in the new species. Among the living forms there is very little resemblance to this species. So, apparently, it belonged to a group of forms of which there are no, or rare, living representatives.” (Wiedey, 1928, p. 136) “Loel and Corey (1932) synonymized Ostrea wiedeyi with 0. loeli, but did not note their similarity with O. howelli. O. loeli was distinguished by a few, low, broadly rounded ribs, 0. wiedeyi by many, prominent, elevated ribs, and O. howelli by a few, prominent, elevated ribs. At localities where specimens are abundant, however, all three forms occur together and are clearly variants of a single species. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA “The shell of O. howelli is thicker, the hinge is thicker and stronger, and the ligament area longer than in 0. vespertina.” (Squires and Fritsche, 1978, p. 19) Comments.— No vesicular shell structure preserved; deeply impressed suboval muscle impression. Pycnodonte?howelli somewhat resembles both P.? loeli and P.? wiedeyi but differs from R? loeli in having a narrower shell with more ribs and from P. ? wiedeyi in having a much thicker shell with fewer radial ribs. Geographic range—Southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros For- mation (Carson, 1965; Squires and Fritsche, 1978). Pycnodonte? (Pycnodonte?) wiedeyi (Hertlein) Plate 15, figures 1, 4, 5, 8 Ostrea wiedeyi Hertlein, 1928, p. 147, pl. 23, figs. 1, 10. Ostrea vespertina Conrad. Avila and Weaver, 1969, pl. 34, figs. 8a, 8b. Not Ostrea vespertina Conrad, 1854. Original description—“Shell moderately large, oblong, moderately thick, flattish; surface marked by 10 to 15 deep radiating plications which have a tendency to become nodose, some of the ribs arise at or near the beaks, others branch from the earlier ones or are interpolated between them; interspaces angular; the ribs internally show only toward the margin. Hinge subtriangular, fairly broad, moderately impressed. Muscle scar large, suboval to subquadrate. Altitude 151 mm.; length 69 mm.; thickness of lower valve 31.5‘mm.” Holotype.—CAS 4129. Type locality—GAS 1154. Santa Rosa Island, Calif. Vaqueros For- mation, Oligocene and Miocene. Supplementary description.—“03trea wiedeyi is extremely variable from a subovate form ornamented by 12 to 15 radial, nodose plications to a long narrow shell with six to eight plications. The ligament pit also varies with the shape of the shell; in the subovate forms it is a short, turned up triangular pit and in the long shells it is a broad fairly deep and slightly depressed scar. These forms all occur in the same zone and apparently the great variation is due to differences in the swiftness of the water currents in which they grew.” (Hertlein, 1928, p. 147) Comparison.—Pycnodonte? wiedeyi *** differs from O. heermanni Conrad by its elongate form, thinner shell and longer ligament pit. From 0. howelli Wiedey it differs in being a much larger shell, orna- mented by more numerous branching corrugations rather than the few straight corrugations on Wiedey’s species. The small ovate forms of O. wiedeyi resemble O. vespertina Conrad but the shell usually has a thicker and larger shell and a greater tendency to adopt an elongate form; also the ligament pit in the present species is often quite depressed, narrowly triangular and longer.” (Hertlein, 1928, p. 147) “Ostrea wiedeyi Hertlein *** bears a strong resemblance exteriorly to O. ueatchii. The shell of this Miocene species [0. wiedeyi] is much thicker and on some specimens the growth lines loop upward to some extent on each side of the ligamental area. Another feature noticed on the interior of these fossils is the presence of a depression just below the hinge on the posterior side of the body cavity. “Loel and Corey considered 0. wiedeyi to be identical with O. loeli Hertlein which they placed as a variety of 0. vespertina. The thick shell, shape of body cavity, and muscle impression, as well as the shape of the hinge line of O. wiedeyi bear a greater resemblance to 0. beer- manni than to typical 0. vespertina. Ostrea wiedeyi bears a close resemblance to Ostrea haitensis Sowerby *** from the late Miocene of Trinidad but the west coast species differs in lacking the transverse vermiculate threads on the margin just below the hinge.” (Hertlein and Grant, 1972, p. 220-221) TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE Comments—Vesicular shell structure was not found on the type specimens but other shell characters seem pycnodontine. The holo- type (pl. 15, figs. 5, 8) is a large, spatulate right valve with a thick shell bearing narrow, rounded, dichotomous ribs on the dorsal half. A few of these ribs continue to the ventral margin as wide, low folds of the shell. The ribs on the entire valve seem to have had hyote spines, subse- quently broken off. One paratype (pl. 15, figs. 5, 8) is a double-valved specimen; the interior is not accessible. The body cavity of the left valve is somewhat larger than the right. Both valves with rounded (at the margins) to knife-shape (on the midportion), irregular, dichotomous, spinose ribs that continue to the shell margins. The commissure is plicate. The upper (right) valve of Dendostrea? uespertina is flatter than the same valve of P.? wiedeyi and bears fewer ribs that are more regular and narrower. Externally the paratype of P.? wiedeyi resembles Hyotissa haitensis (Sowerby) of Woodring (1982, pl. 98, fig. 2). Geographic distribution—Southern California. Geologic distribution—Oligocene and Miocene. Occurrence in California.——Oligocene and Miocene: Vaqueros For- mation (Hertlein, 1928). Pycnodonte? (Pycnodonte?) loeli (Hertlein) Plate 18, figures 7, 8 Ostrea loeli Hertlein, 1928, p. 144, pl. 22, figs. 2, 3. Ostrea uespertina (Conrad) loeli (Hertlein). Loel and Corey, 1932, p. 193-194, pl. 16, figs. 1a, 2; pl. 17, figs. 1a, 1b, 2a, 2b, 3. Original description—“Shell quadrate, thick, slightly arched; made up of many layers of shell material; shell shows about 6 coarse, radial, corrugations which are but little developed or absent in the early part of shell but which are pronounced in the adult. Ligament pit broad, prominent, distinctly depressed; body cavity sharply depressed on one side; muscle scar large, depressed, situated on posterior side of shell about one third the length of shell from ventral margin. Height, 130 mm.; length, 100 mm.; thickness, lower valve, 38 mm.” Holotype.—CAS4117. Type locality—OAS 1153. Santa Rosa Island, Santa Barbara County, Calif. Vaqueros Formation, Oligocene and Miocene. Comparison—“This heavy oyster resembles Ostrea heermanni Conrad from the Pliocene of Imperial County, California but it is more quadrate in outline, thicker, and it possesses fewer and heavier plica- tions which are prominent only on the ventral part of the shell; it also has a distinctly depressed body cavity and longer hinge line.” (Hertlein, 1928, p. 144) “0. loeli Hertlein is a less common variant in the Vaqueros horizon which differs from O. wiedeyi Hertlein mainly in degree of sharpness of plications. It may be considered to be of varietal value. Most spec- imens of the latter form show the six primary plications on the younger part of the shell. ‘0. loeli Hertlein,’ in retaining these into the adult form, shows a tendency toward 0. heermanni Conrad (1885) of the Lower Pliocene.” (Loel and Corey, 1932, p. 194) “Loel and Corey considered 0. wiedeyi to be identical with 0. loeli Hertlein which they placed as a variety of O. vespertina. The thick shell, shape of body cavity, and muscle impression, as well as the shape of the hinge line of 0. wiedeyi bear a greater resemblance to O. heer- manni than to typical 0. vespertina.” (Hertlein and Grant, 1972, p. 220-221) Comments. —No vesicular shell structure was found on the type, but other shell characters are pycnodontine. See also Pycnodonte? howelli above. Geographic range—Southern California to Baja California Sur. Geologic range—Oligocene and Miocene. Occurrence in the Californias.—Oligocene and Miocene: Rincon Shale (Avila and Weaver, 1969) and Vaqueros Formation (Dickinson, C21 1966; 1969; Vedder, 1973); Miocene: Comondu (Mina, 1956), Topanga (J.G. Vedder, written commun., 1978) and Tortugas (Minch and others, 1976) Formations. Pycnodonte? (Pycnodonte?) heermanni (Conrad) Plate 13, figures 1, 4, 6, 7; plate 14, figure 4; plate 16, figure 4; plate ‘ 17, figs. 6, 7 Ostrea heermanni Conrad, 1855, p. 267. G D. Hanna, 1926a, p. 467, pl. 22, figs. 7, 8; pl. 23, figs. 1, 2. Ostrea veatchii Gabb, 1869, p. 60-61, pl. 17, figs. 21-21a. Not Ostrea veatchii Gabb, 1869, p. 34-35, pl. 11, fig. 59. Original description.—“Very irregular in form, thick, ovate and often dilated; lower valve shallow; exterior very irregular, with large distant angular radiating ribs and with pits, irregular cavities; car- tilage pit broad and oblique; upper valve flat or concave, with a pro- f0undly irregular surface. Length, 5.75 inches; height, 6.5 inches.” ‘ Holotype.—AN SP 13367 (Woodring, 1938, p. 46); 4 specimens in type lot all are numbered 13367. ‘ Type locality—Colorado Desert, Imperial County, Calif. Imperial Formation, Miocene or Pliocene. ‘ Supplementary description—“Although this species has not been p‘reviously figured, so far as I have been able to determine, there is no mistaking the fact that Conrad had specimens of the only large cir- cular oyster of the Coyote Mountain region. It is excessively abundant in many places and also excessively variable. Uneroded specimens, however; show clearly that it is an irregularly ribbed species.” (G D. Hanna, 1926a, p. 467) ‘ Comparison—“Small shells varying in outline from circular-ovate to ovate-falcate are associated with large specimens of heermanni and some of intermediate size *** from the lower part of the Imperial Formation. Some of these small specimens (length 37.8 to 44.4 milli- meters) have fewer and broader plications than uespertina, but some ovate—falcate specimens (length 27.3 to 40.7 millimeters) are indis- tinguishable from that form in outline, plication, fluting of the inner inargin, and character of the ligament area. The possibility that two species of plicate oysters are represented at this locality seems to be remote. These small specimens indicate that vespertina from the upper part of the Imperial Formation is a form of heermanni and that heermanni should be treated as a nomenclatural variety of vespertina. Nevertheless, it does not seem desirable to unite heermanni with vespertina, for typical heermanni is readily distinguishable from any lot of small oysters from the upper part of the Imperial Formation.” (Woodring, 1938, p. 46) Comments. —A left valve of R ? heermanni, collected from the Impe- rial Formation by Charles L. Powell, U.S. Geological Survey, clearly :shows vesicular shell structure on the inside of the valve near the ‘commissure; this structure was not seen on the specimens in the type ‘lot. The shell is thick, mostly smooth with a few irregular subdued ‘plications and a very small attachment area. Two fragments seem to ‘ have had auricles, and the largest specimen in the type lot (pl. 13, figs. 1 6, 7), a right valve, is produced at the anterior margin. The chomata ‘ are vermiculate, the chomatal trough well defined, and the com- ‘ missural shelf is prominent. These characters combined place heer- ‘ manni in the subfamily Pycnodonteinae (Stenzel, 1971, p. N1105), yet ‘ the species does not fit satisfactorily into any of the described genera in ‘ that subfamily. Geographic range—Southern California to Baja California Sur. Geologic range.——Miocene(?); Pliocene. Occurrence in the Californias.—Miocene or Pliocene: Imperial For- , mation (G D. Hanna, 1926a); Pliocene: Almejas(?) (Minch and others, , 1976), and Infierno (McFall, 1968) Formations and unnamed strata at , San Felipe (Hertlein, 1968). C22 Subgenus CRENOSTREA Marwick, 1931 Left valve umbo prominent, rising well above hinge line; no auricles; outline vertical oval; posterodorsal valve margin not geniculate; Chomata strong, straight, most not branching; radial ribs short, gently undulatory; many variable prominent concentric puckers and welts. Geographic range—New Zealand, California(?). Geologic range.—Eocene(?); Oligocene and Miocene (table 6). Subgenus CRENOSTREA? Pycnodonte? (Crenostrea?) stewarti (M. A. Hanna) Plate 19, figures 4, 7, 8 Ostrea stewarti M. A. Hanna, 1927, p. 276, pl. 28, fig. 1; pl. 29, fig. 3; pl. 30, fig. 3. Original description—“Species of medium size, massive, pyriform to subcircular in outline, beak straight; surface bears only prominent partially overlapping growth scales; one valve nearly flat, the other moderately inflated; hinge area massive; central depression of hinge concave, nearly parallel-sided, much deeper in the convex valve; area to either side of the depression flat, and about equal in width to the depression; just posterior to the hinge the margin is denticulate with narrow sharp teeth, which are separated by round—bottomed inter- spaces, teeth best developed in the flat valve; adductor scars large, subcircular, nearly central and just below the hinge; adductor in the convex valve located in a deep pit. Dimensions: Altitude from the beak to the ventral 115 mm., length 115 mm., width of the hinge 45 mm., thickness of the shell of the convex valve 30 mm., diameter of the convex valve 50 mm.” Syntypes.—UCMP 30921, 30922. Type locality.—UC 5062. San Diego County, Calif. Rose Canyon Shale (M.A. Hanna, 1926), Eocene. Comparison—“The massiveness of the shell, the position and the shape of the adductor scars, and the general character of the hinge may be used to distinguish Ostrea stewarti n. sp. from other West Coast species.” (M. A. Hanna, 1927, p. 276) Comments—The syntypes are a right and a left valve. Although the valves seem to fit together at the ventral margin, they gape markedly at the dorsal margin and the ligamental areas are widely separated. The left valve is almost ovate, the right valve pyriform. The muscle impressions are large and subcircular and positioned near the liga— mental areas. The left-valve muscle impression is in a deep pit, unlike any I have seen on other Eastern Pacific Tertiary oysters. Both valves are thick for their size; the left more so than the right. Chomata are preserved on the right valve; no vesicular shell structure was seen. The left valve may have had a radial posterior sulcus, has no radial ribs, but does have concentric puckers. The exterior shell of the right valve is not preserved. Geographic range—Southern California. Geologic range—Eocene. Occurrence in California—Eocene: Rose Canyon Shale (M. A. Hanna, 1927) and unnamed strata in the Transverse Ranges (Squires, 1977). Pycnodonte? (Crenostrea?) eldridgei (Arnold) Plate 21, figures 1, 4 Ostrea eldridgei Arnold, 1907a, p. 528, pl. 42, figs. 2, 2a. Arnold and Anderson, 1907, pl. 18, figs. 6a, 6b; not pl. 16, fig. 2 (: O. eldridgei ynezana). Loel and Corey, 1932, p. 188, pl. 11, figs. 1a,1b, 2. Hertlein and Jordan, 1927, p. 622. Hanna and Hertlein, 1943, p. 174, fig. 63-16. Squires and Fritsche, 1978, p. 19, pl. 4, fig. 1. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Original description. —“Shell about 150 mm. in length, inequivalve, the left very convex, the right flat or slightly concave. Left valve with incurved umbo; a prominent, falcate, evenly convex ridge extends from near the umbo to the margin of the left valve posteriorly; surface of this valve and ridge foliaceous and more or less inclined to be fluted. Left valve approximately flat, with foliaceous surface.” Holotype.—USNM 164966 [erroneously cited as 164968 in Keen and Bentson, 1944]. Type locality—[Oak Ridge], Elkins Ranch, east of Grimes Canyon, near Fillmore [sec. 7, T. 3 N., R. 19 W., Piru Quad], Ventura County, Calif. Vaqueros Formation, Oligocene and Miocene. Supplementary description. —“Ostrea eldridgei Arnold is most vari- able in thickness and ornamentation. The collections examined indi- cate the existence of two major forms or variants, often found in association, with perfect intergradation. One or the other form is usually in dominance of numbers in any single zone. Arnold figured both forms, the heavier thicker form, lacking plications or ‘frills’ was the first figured and the one described by him.” (Loel and Corey, 1932, p. 189.) Comparison—“This species is distinguished from the other Terti- ary oysters of the California Tertiary by the prominent posterior ridge and incurved umbo of the left valve. The species has the external appearance of a Gryphaea.“ (Arnold, 1907a, p. 528) Comments—The shell characters of P.? (C?) eldridgei seem pycno- dontine, but it is not known if the species has vesicular shell structure. The posterior radial sulcus indicates placement in Crenostrea. Geographic range—Middle California to Baja California Sur. Geologic range—Oligocene and Miocene. Occurrence in the Californias.—Oligocene and Miocene: Soda Lake and Quail Canyon Sandstone Members of the Vaqueros Formation (Vedder, 1973), Vaqueros Formation (Addicott, 1972; Squires and Fritsche, 1978; Dickinson, 1969); Miocene: Isidro(?) Formation (Hertlein and Jordan, 1927) and Monterey Shale (Weaver, 1949). Genus HYOTISSA Stenzel, 1971 Valves similarly sculptured, left valve slightly more convex; attach- ment area large to very large; commissure plicate in free-growing individuals; ribs crude, irregularly dichotomous, tops mostly rounded and crossed by prominent nonappressed growth squamae. Noninterlocking, adjacent, vermicular ridges, occurring only near the ligament in both valves, are regularly present in Hyotissa. Hyotissa 3.3. may have a few lath Chomata below the vermiculate Chomata. For variation within one species of Hyotissa, see H. haitensis (Sowerby) figured by Woodring(1982, pl. 98, fig. 2; pl. 103, fig. 7; pl. 105, figs. 10, 11; pl. 109, figs. 6, 9-12) from the Emperador Limestone Member, La Baca Formation, Miocene, Panama. Geographic range—Worldwide. Geologic range—Cretaceous to Holocene (table 7). Habitat. —The genus is euhaline, stenohaline, and stenothermal, a member of the compound-coral biocoenosis (Stenzel, 1971, p. N1108). Hyotissa hyotis (Linné) Plate 16, figures 1, 2 Mytilus hyotis Linné, 1758, p. 704, no. 217. Linné, 1767, p. 1155, no. 244. Ostreajacobaea Rochebrune, 1895, p. 241. Not Ostreajacobaea Linné, 1758. Ostrea fisheri Dall, 1914, p. 1, new name. Hertlein, 1957, p. 65-66. Ostrea fischeri Dall. Durham, 1950, p. 59, pl. 6, figs. 1, 4. Olsson, 1961, p. 173—174, pl. 23, fig. 6. Original description—“M. testa plicata imbricata squamis com- pressis patulis, labro utroque laevi.” (hyotis) TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE 023 TABLE 7.——Geologic and geographic distribution of the genera Hyotissa, Neopycnodontef, Lopha?, and Dendostrea? in the eastern Pacific region [H=Holocene; Ple=Pleistocene; PlzPlibcene; MxMiocene; O=Oligocene| Species California Baja California Central ‘ or South Northern Middle Southern Norte Sur America. Genus Hyotissa hyotis (Linné) .................................................... Pl to H Pl to H Genus Neopycnodonte? cf. cochlear (Poli) .................................................... Pl ----- Genus Lopha? Subgenus “Lopha” veatchii (Gabb) ..................................... P1 and Ple Pl Pl """ Genus Dendostrea? angelica (Rochebrune) .............................. M and P1 Pl Pl to H """ angermanni (Hertlein and Jordan) --------------- O to Pl? ~~~~~ M ----- vesperlina (Conrad) ................................ M and P1 M and P1 Pl Pl Pl “Testa sublibera, apice inferiori tantummodo adherens; crassiuscula subrotundata, complanata, ad marginem plicato crenata; umbonibus rectis, abbreviatis, pyramidatis; ligamento elongato, sub- angustato, longe arcuato; valvis subaequalibus, transverse nodoso undulatis et radiatim late plicato costatis, plicis irregularibus, obscure squamatis, obtusis, interruptis; impressione subcentrali, rotundate evato; extus violacca et sordide luteo tincta; intus albonitida, vel cereo subpurpureoque peruncta; fuscoviolaceo late marginata.” (fisheri) Holotype.——Missing. According to Dodge (1952, p. 206), unmarked specimens of the species are found in the Linnaean collection, but none can be used as the type, because the name hyotis does not appear on Linné’s list of owned species, thus raising the probability that the specimens were added later and possibly by someone else. Of Ostrea fisheri, in Museum Nationale d’Histoire Naturelle de Paris. Type locality—In Pelag'i Gorgoniis; of fisheri, lles de la Baie de la Paz. Supplementary description—“Shell large (length 120 mm), subcir- cular to obliquely oblong, thick, generally strongly plicated with six or more heavy ribs and sharp folds, heaviest near the margin, similar in both valves. These ribs occasionally develop irregular hollow tubular extensions. *** Adductor scars large, placed slightly posterior of the middle Cardinal area wide and heavy. Substance of the shell is thick, made up of porcellaneous layers interfingered with porous and cel- lular seams. “Typical specimens have a round, thick shell with strong ribs *** Other specimens which have grown attached to smooth piling will have a flat or curved surface and a relatively thin shell without ribs.” (Olsson,1961, p. 173,174) “*** an extremely variable species, especially in the degree of development of the tubular processes arising from the imbricate layers of the upper valve, and the available figures are confusing in that they usually represent the most highly developed form in this respect, a form that is rarely seen” (Dodge, 1952, p. 206). Comparison.—Hyotissa quercinus (Sowerby), a species living at . Bahia de los Angeles, differs from H. hyotis in being smaller with radial plicae rare, small, and local. The left promyal passage is closed ‘ in H. quercinus whereas it is open in H. hyotissa. (Harold W. Harry, written commun, 1983). Comments.—Hyotissa hyotis has vesicular shell structure, irreg- ularly dichotomus ribs with hyote spines, and prominent nonap- pressed growth squamae. ‘ Geographic range—Living: East Africa and Madagascar to south- ern Japan; Golfo de California to Ecuador and Galapagos Islands; pssil: Baja California Sur to Mexico. , Geologic range—Pliocene through Holocene. ‘ Occurrence in Baja California—Pliocene: Carmen (Durham, 1950). Infierno (Wilson and Rocha, 1955), Marquer (Durham, 1950), and San Marcos (Durham, 1950) Formations and unnamed strata at Rancho El Refugio and Isla Cerralvo (Hertlein, 1966); Pleistocene: Santa Rosalia Formation (Wilson, 1948) and unnamed strata on Isla Carmen (Hertlein, 1957). Genus NEOPYCNODONTE Stenzel, 1971 , Shell walls very thin, outline variable, many individuals auriculate. Left valve deep and capacious, posterior half rising vertically from substratum attachment so that the hinge axis is at 45°. Left valve ‘mostly smooth but older individuals have paper-thin foliaceous ‘imbrications near ventral margin and some may be drawn out into ‘long hyote or spoon-shaped extensions. Auricles on either side of hinge :common, foliaceous, and imbricated. Commissural shelf on left valve only in dorsal half. Adductor muscle imprint large, diameter about one-fourth that of valve height. Right valve flat to concave with a few (radial gashes. Commissural shelf on right valve nearly complete ‘around periphery. Geographic range—Worldwide. Geologic range. —Oligocene to Holocene (table 7). Habitat —The type species, Ostrea cochlear Poli, is stenohaline and euhaline in oceanic waters of 12- 14 °C and at depths of 27- 1500 m. (,Stenzel 1971 p. N1111). Genus NEOPYCNODONTE? Neopycnodonte? cf. N. cochlear (Poli) Plate 32, figures 3, 7 Two specimens were figured by Durham (1950, pl. 5, figs. 4, 6) as Ostrea cumingiana Dunker. The specimen illustrated 1n figure 6 is Dendostrea? angelica (Rochebrune), and it is included herein in that synonymy and illustrated in plate 34, figure 2 The specimen Durham i (1950) illustrated in figure 4 resembles Neopycnodonte cochlear (Poli, C24 1795, p. 179) and is illustrated in plate 32, figures 3, 7. I have included it to call attention to the probable presence of Neopycnodonte in the eastern Pacific. Geographic range—Baja California Sur. Geologic range—Pliocene. Occurrence in Baja California Sur. —Pliocene: Marquer Formation (Durham, 1950). Family OSTREIDAE Adductor muscle scar usually concave dorsally or flattened. Chomata of pustules in right valve with or without pits to receive them in left valve. Chomata absent in some genera throughout postlarval life or occasionally in larger specimens of a few genera. Chalk deposit when present not vesicular. Commissural shelf rarely well defined. Subfamily LOPHINAE Attachment area medium size to large; some genera with shelly claspers that grow out at intervals from plicae of left valve to lock onto substrate. Valves subequal, with similar rib patterns of regular, sube- qual, fairly sharp-crested plicae producing a regularly plicate valve commissure. Chomata are minute pustules that usually form a moderately broad, usually interrupted submarginal band completely around both valves. Pits to receive the pustules are absent in the opposite valve. The chomata are aligned on the protochomata with none to three on adjacent bands. Other Chomata may be present as a single row of pustules in right valve with pits to receive them in left. Chalk deposits are lacking, and there are many chambers. (Harry, 1983, p. 90) Genus LOPHA Roding, 1798 Attachment area medium to large. Some species often have shell claspers that grow out at intervals on plicae of left valve to lock onto substrate. Valves subequal in size and convexity with similar rib patterns of regular, subequal, fairly sharp-crested plicae with flat sides which produce a regularly plicate valve commissure. Geographic range—Worldwide in the tropics and partly in the subtropics. (Restricted to tropical Indo—Pacific in Holocene.) Geologic range.—Triassic(?) to Holocene (table 7). Genus LOPHA? Subgenus “LOPHA” Lopha? (“Lopha”) veatchii (Gabb) Plate 17, figures 1-5 O[strea] veatchii Gabb, 1866, p. 34-35, pl. 11, fig. 59; not 1869, p. 60-61, pl. 17, figs. 21, 21a [ : Ostrea heermanni Conrad]. Ostrea ueatchii Gabb. Heilprin, 1884, p. 316, pl. 72, fig. 1. Hertlein and Grant, 1972, p. 219-221, pl. 39, fig. 4; pl. 40, figs. 1, 4-6. Ostrea haitensis Sowerby subsp. vespertina Conrad. Stewart, 1930, pl. 14, fig. 4. Not Ostrea vespertina Conrad, 1854. “Ostrea” veatchii Gabb. Smith, 1984, p. 206, pl. 4, fig. 6. Original description—“Shell large, subequivalve, varying from nearly equilateral to very oblique, the obliquity being always to the left side. Surface marked by ten or a dozen large, angular, radiating ribs, some of which arise at or near the beaks, the others branching from the first, or interpolated between them; the interspaces are angular, and the ribs are marked by more or less squamose plates, and occa- PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA sionally these plates assume almost the character of spines; internally the ribs show only towards the margins. Hinge short, very broad and shallow; no crenulations or denticulations near the margin. Muscular scar large, suboval to subquadrate.” Holotype.—AN SP 4502. Type locality—Germs [Cedros]lsland, Baja California Norte. Alme- jas Formation, Pliocene. Supplementary description—“The type is a comparatively thin (about 4 mm) lower valve, 75 mm high and 68 mm long, the upper anterior margin incomplete. The exterior is sculptured with about 10 angular, radiating ribs which at intervals develop into spines. Inte- riorly there is no recessed area under the hinge, the muscle impres- sion is fairly large and rounded, and as mentioned by Gabb, there are no denticles along the margin of the valve. An upper valve, about the same size, gently convex, sculptured similar to the type, is in the type lot.” (Hertlein and Grant, 1972, p. 220) Comparison—“The gently arched upper valve, more numerous, spinose ribs which deeply interlock along the ventral margin and the smooth margins totally lacking denticles are shell characters quite different from those of 0. vespertina from its type locality. “Exteriorly some specimens of O. angelica bear a close resemblance to O. veatchii. *** The shell of O. angelica is usually thicker, the flutings usually do not extend to the dorsal third of the valves and do not develop into spines, interiorly the margins below the ligamental pit are finely denticulate, and the muscular impression is semicircular in outline. “Examination of about 50 specimens from Pliocene strata on Cedros Island, the type locality of O. veatchii, and of additional specimens from Bahia Tortolo (Turtle Bay), Lower California, reveals considera- ble variation. Some of these agree exactly with Gabb’s type and lack denticles on the margin. Others, usually smaller, more trigonal or falcate forms have very fine denticulation only along the upper portion of the margin, others have denticulation similar to that on O. vesper- tina. Also occurring at Cedros Island are specimens agreeing in every way with O. angelica. The variation in this series from Cedros Island is such as might lead one to question whether perhaps some of these are hybrids between 0. ueatchii and O. angelica. For the present we believe it desirable to retain O. veatchii as a separate taxon at least until the relationships of west American oysters are better known. “Ostrea wiedeyi Hertlein described from early Miocene strata on Santa Rosa Island, California, bears a strong resemblance exteriorly to O. veatchii. The shell of this Miocene species is much thicker and on some specimens the growth lines loop upward to some extent on each side of the ligamental area. Another feature noticed on the interior of these fossils is the presence of a depression just below the hinge on the posterior side of the body cavity. “Ostrea veatchii, at times, has been placed in the synonymy of O. haitensis Sowerby, a species occurring in strata of Miocene age in the Caribbean region. The west American shell represents a similar but distinct species with a thinner shell and without denticles or trans- verse threads on the margin.” (Hertlein and Grant, 1972, p. 220-221) Comparison—Pymodonte? wiedeyi (Hertlein) is thicker shelled and has more radial plicae, which are not as sharp-crested nor as high as the plicae on L.? ueatchii, and the hyote spines are smaller. Comments.—Lopha? veatchii has irregular ribs that are rarely dichotomous, hyote spines on young individuals, and very prominent nonappressed growth squamae. The specimen (holotype) first described as 0. veatchii (Gabb, 1866) and later figured by Gabb (1869, p. 34-35, pl. 11, fig. 59) is thin shelled and moderate in size. It has strong, sharp, radial plicae, some with hyote spines, 3 plicate commissure, no commissural shelf, and no vesicular shell structure. Because it has lophine characteristics, it is here assigned to Lopha ?. Subsequently, Gabb (1869, p. 60-61, pl. 17, figs. 21, 21a) described and figured another specimen (hypotype) that 7’4 4* TERTIARY MARINE PELECY'PODS: PLICATULIDAE AND OSTREIDAE 025 he identified as 0. veatchii. This specimen is a very thick shelled left valve with numerous irregularly placed, rough-topped ribs, a strong commissural shelf, and vesicular shell structure. It is identified here as Ostrea heermanni Conrad, a species that has pycnodontine charac- ters, and is assigned to Pycnodonte .9. Hertlein and Grant (1972, p. 220) noted that this specimen resembled O. heermanni. Stewart (1939, p. 128-130) placed 0. veatchii and O. heermanni into synonymy with O. vespertina, an example of the difficulty that workers have had differentiating fossil oysters. Ostrea vespertina is assigned here to Dendostrea ?. The specimen illustrated by Stewart (1930, pl. 14, fig. 4) as an example of O. vespertina is the holotype of O. veatchii. Lopha? veatchii differs from Lopha chiefly by the absence of fine pustules in crowded rows on the extensions of both valves (H. W. Harry, written commun., 1984). Geographic range—Southern California to Baja California Sur. Geologic range—Pliocene and Pleistocene. Occurrence in the Californias.—Pliocene: Almejas (Mina, 1957), Cantil Costero (Hertlein and Allison, 1959), Carmen (Durham, 1950), Marquer (Durham, 1950), Niguel (J.G. Vedder, written commun., 1978), San Diego (Hertlein and Grant, 1972) and San Marcos (Durham, 1950) Formations and unnamed strata on Isla Tres Marias (Hertlein and Emerson, 1959); Pliocene and Pleistocene: Fernando (Arnold, 1907c; English, 1914), Pico (Kew, 1924), and Saugus (Kew, 1924) Formations. Genus DENDOSTREA Swainson, 1835 Small (as much as 8.5 cm high); both valves convex, equivalve, shape lanceolate to ovate, usually with many rounded to sharp radial plicae. Surface without any pustules, but with many fine, closely set growth squamae. Hollow recurved hyote spines arise intermittently from crests of plicae of left valve; several of them serve as claspers for left valve embracing stem of coral and gorgonaceans, but clasper spines are usually not present. Dendostrea is highly variable in size, shape, and plications. Usually the marginal commissure is finely zigzag, at least in some sections. Chomata are variable, being ostreine usually, sometimes both ostreine and lophine, and rarely only lophine. (Harold W. Harry, written commun., 1984) The exterior surface of Dendostrea is never pustular as that of Lopha s.s., and there are no fingerprintlike markings inside as in Alectryonella. Ostreola is about the same size as Dendostrea, but plications are generally present only on the left valve. (Harold W. Harry, written commun., 1984) Geographic range—Worldwide. The eastern Pacific Tertiary spe- cies are all questionably assigned to Dendostrea. Geologic range—Miocene to Holocene (table 7). Habitat—Tropical and partly subtropical; usually attached to stony coral, often attached to gorgonians (sea fans). Genus DENDOSTREA? Dendostrea? angermanm' (Hertlein and Jordan) Plate 31, figures 1-6, 8 Ostrea angermanni Hertlein and Jordan, 1927, p. 621, pl. 17, figs. 3, 6. Clark, 1929, p. 21, pl. 19, fig. 3. Original description—“Right valve rather small, subquadrate in outline, moderately arched; an unornamented area covers beak and umbonal region, remainder of shell ornamented by 15 to 20 medium fine, well developed radial plications. Interior of valve moderately deep, sloping from margins of shell to point of greatest concavity at center; hinge shows narrow ligament pit running to anterior dorsal edge of shell; dorsal and parallel to this another longer, narrow pit follows posterior dorsal edge of shell; margins of shell marked with small crenulations. Height 46.2 mm.; length 38.9 mm.; greatest diam- eter of shell 13.1 mm.” Holotype.—CAS/SU 5137. Type locality.—SU 59. Baja California Sur, Isidro(?) Formation, Miocene. Comparison—“Ostrea angermanni differs from O. vespertina Con- rad in possessing a different hinge in which the pits are narrow and run obliquely across hinge to anterior dorsal margin of shell; further- more, the present species possesses many more and much finer radial plications on the exterior of the valve. From Ostrea (Alectryonia) plicata Chemnitz and O. edulis Linnaeus, O. angermanni can be distinguished by the more numerous and finer radial plications orna- menting the right valve. 0. angermanni differs from O. sellaformis var. thomasii Conrad, in that the lower valve of the present species is more quadrate in outline, it is apparently more highly arched and is orna— mented by finer ribs.” (Hertlein and Jordan, 1927, p. 621) Comments—The right valve is very inflated compared to the size of the shell. Although this species seems to belong in the subfamily Lophinae, its characters don’t fit well into any of the genera assigned to that subfamily by Stenzel (1971, p. N 1157). Geographic range—Southern California to Baja California Sur. Geologic range.-—Oligocene to Pliocene(?). Occurrence in the Californias.—Oligocene and Miocene: Vaqueros Formation (Clark, 1929); Miocene: Isidro(?) Formation (Hertlein and Jordan, 1927); Miocene or Pliocene: Imperial Formation (Bramkamp, 1935). Dendostrea? vespertina (Conrad) Plate 11, figures 2, 5; plate 12, figures 2, 5, 6; plate 13, figure 5; plate 14, figure 2; plate 15, figures 2, 3, 6, 7; plate 16, figures 6, 7 Ostrea vespertina Conrad, 1854, p. 300. Conrad, 1857d, p. 325, pl. 5, figs. 36-38. Arnold, 1909, p. 77, pl. 24, figs. 4, 5. G D. Hanna, 1926a, p. 468, pl. 26, figs. 1-3. Grant and Gale, 1931, p. 152, pl. 12, figs. 1a, 1b. Woodring, 1938, p. 42-47, pl. 8, figs. 1-4, 89; pl. 9, fig. 5. Woodring in Woodring and Bramlette, 1950, p. 85, pl. 16, figs. 4, 17. Hertlein and Grant, 1972, p. 218-219, pl. 39, figs. 1-3, 5-9. Addicott in Addicott and Galehouse, 1973, p. 511, 513, fig. 3a-c, h, 1- n. Ostrea vespertina Conrad var. sequens Arnold, 1909, p. 79-80, pl. 29, figs. 5, 6. Woodring in Woodring and others, 1940, p. 92, pl. 8, figs. 10-14; pl. 10, figs. 1-5. Ostrea haitensis Sowerby subsp. vespertina Conrad. Stewart, 1930, p. 128-130, pl. 14, fig. 4. Not Ostrea vespertina Conrad. Durham, 1950, p. 59, pl. 5, figs. 1, 2, 5, 7 84 [= Ostrea angelica Rochebrune]. Original description.—“Ovato-subfalcate, lower valve plicated or ribbed; hinge long and wide, sharp and somewhat pointed; ligament cavity wide, profound, minutely wrinkled; margins abrupt, cavity not very deep; muscular impressions large, impressed; upper valve flat, irregular; pallial impression crenulated throughout its whole extent, profoundly crenulated on the upper half of the shell. From beak to base 1%; transversely 1V2.” (vespertina) “Shell averaging about 42 mm., in length, subcircular in outline, irregular, plaited, usually with three major plaits, each of these some- times sulcate or divided into minor plaits; foliaceous lines of growth not as prominent as in many species of Ostrea; beak prominent, curved toward right when viewed from exterior. Right valve nearly flat or only slightly folded, the plaits practically obsolete; incremental laminae as in left valve; hinge not strong, subdentate laterally in left valve; muscle scars prominent.” (vespertina sequens) C26 Lectotype.—Ofvespertina AN SP 13366 (Woodring, 1938, p. 43); holo- type of vespertina sequens USNM 165545. Type locality. —Of vespertina, near San Diego [Carrizo Creek, Impe- rial County fide Woodring, 1938, p. 43], Calif. Imperial Formation, Miocene or Pliocene; of vespertina sequens USGS 4728, Kings County, Calif. San Joaquin Formation, Pliocene. Supplementary description—“Left valves are strongly to moder- ately plicate; right valves are moderately plicate to warped, some small right valves being practically flat. The ligamental groove is shallow, relatively wide, and rapidly tapering. The inner margin below the ligament area is generally strongly denticulate, but is weakly denticulate to smooth, or practically smooth, on a few valves. With few exceptions, the umbo is twisted in a counterclockwise direction when the shells are viewed in attached position.” (Woodring, in Woodring and Bramlette, 1950, p. 85) “The lower valve is usually convex, bearing 5 to 10 plications, and the upper valve is flattish and fits down into the fluting around the mar- gin. The margin below the ligamental area bears denticulations which sometimes occur along the margin for half the length of the valve.” (Hertlein and Grant, 1972, p. 218-219) Comparison.~“0. uespertina is smaller, relatively narrower, and usually more falcate in outline and carries plaits more regular in size and generally fewer in number than 0. haitensis. ” (Arnold, 1909, p. 78) “Perhaps the average Recent specimen [Ostrea palmula Carpenter, 1856] has the upper margins a little more fluted and the excavation under the beak of the lower (left) valve a little deeper but these features are variable in a large series. “The large oyster from Imperial Co., California, named Ostrea heer— manni by Conrad has an ovate, flattish, very thick shell. The body cavity is fairly deep on the anterior side and the exterior flutings are reflected interiorly along the margins of rather thin valves, but not on thick valves. The growth lines are decidedly looped upward on each side of the ligamental area, distinctly different from those of O. vesper— tina which are but slightly or not at all looped upward. “Some authors have considered a close relationship to exist between 0. vespertina, O. haitensis Sowerby, O. heermanni Conrad, and O. wiedeyi Hertlein. The latter three species bear a greater resemblance to 0. veatchii Gabb * * * Studies of the type lot of O. Hespertina and other specimens from the type locality, also the selection of a lectotype by Woodring, have furnished a basis for separating this species from typical 0. veatchii with which it has been united by some authors.” (Hertlein and Grant, 1972, p. 219) Comments—I have not seen hyote spines or vesicular shell struc- ture on D.? uespertina. I place the species in Dendostrea? on the basis of its plicate margin, crude, irregularly dichotomous plicae, and rather large attachment area. Mostly the muscle scar is prominent, rounded medially and pointed peripherally, and distinctly concave on dorsal margin. Addicott (in Addicott and Galehouse, 1973, p. 510-511) considered Ostrea vespertina sequens to be a small, weakly sculptured form of O. vespertina, a decision with which I concur. Geographic range—Middle California to Mexico (Hertlein and Grant, 1972, p. 219). Geologic age—Miocene and Pliocene. Occurrence in the Californias.—Miocene: Castaic (Stanton, 1966) and Santa Margarita (Nomland, 1917; Adegoke, 1969; Addicott and others, 1978) Formations; Miocene and Pliocene: Etchegoin Formation (Adegoke, 1969); Miocene or Pliocene: Imperial Formation (G D. Hanna, 1926a; Stump, 1979); Pliocene: Almejas (Emerson and Hertlein, 1960), Boleo (Wilson, 1948), Cantil Costero (Hertlein and Allison, 1959), upper part of Capistrano (Kern and Wicander, 1974), Carmen (Durham, 1950), Fernando (Woodring, 1938; Durham and Yerkes, 1964; Vedder, 1972), Gloria (Wilson, 1948), Infierno (Wilson, 1948), Marquer (Durham, 1950); Niguel (Vedder, 1972), upper part of Paso Robles (Addicott and Galehouse, 1973), Pico (Winterer and PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Durham, 1958), Purisima (Allen, 1946; Wilkinson, 1963), San Diego (Hertlein and Grant, 1972), San Ignacio (Mina, 1957), San Joaquin (Woodring and others, 1940), San Marcos (Durham, 1950), lower part of Saugus (Squires and White, 1983), and Towsley (Winterer and Durham, 1958) Formations. Dendostrea? angelica (Rochebrune) Plate 32, figures 1, 8, 9; plate 34, figures 2, 7, 9, 10 Ostrea angelica Rochebrune, 1895, p. 241-242. Keen, 1971, p. 82, fig. 167. Emerson and Hertlein, 1964, p. 353, figs. 3a-3c. Hertlein and Grant, 1972, p. 216-217, pl. 38, figs. 2, 3. Lopha angelica (Rochebrune, 1895). Bernard, 1983, p. 24. ?Ostrea cumingiana Dunker. Durham, 1950, p. 58, pl. 5, fig. 6. Not Ostrea cumingiana Dunker, 1846. Ostrea vespertina Conrad. Durham, 1950, p. 59, pl. 5, fig. 7; not pl. 5, figs. 1, 2, 5. Not Ostrea vespertina Conrad, 1854. Original description.—“Testa aggregata, plerumque irregulariter ovoideo rotundata, apice plus minusive attenuata, ad marginem undu- lato dentala; umbonibus arcuatis, ligamento oblique; valvis inae- qualibus; valva inferiore subprofunda, intense adherens, circulariter radiatim costata; costis crassis subangulosis; valva superiore plana, centraliter corrugata, circulariter radiatim costata, costis irreg- ularibus, obtusis plicatis, plicis imbricatis latis; extus albo viridula, intus albo nitida virescente; impressione subcentrali albo, tra- pezoideo; marginibus lateralibus prope umbonibus, minutissime den- ticulatis.” Holotype.—In Musée Nationale d’Histoire Naturelle de Paris. Type locality—Bahia de Los Angeles, east coast of Baja California Sur. Holocene. Supplementary description—“Recent specimens of O. angelica are usually oblong or rounded and the shell is rather thick. The lower valve is decidedly convex, the upper one only gently so. Both valves are sharply plicated over the distal half or one third of their surfaces which interlock along the margin, but the plications usually do not extend much beyond the pallial line on the interior of the valves. * ** Denticles or transverse vermiculations are present on the margins from the ligamental pit usually to about a third the distance to the ventral margin. The muscle impression is posterior to the center, trapezoidal in shape.” (Hertlein and Grant, 1972, p. 217) Comparison—“Small specimens of 0. angelica differ from O. lurida laticaudata Carpenter in the greater thickness of the shell, the more convex upper valve which is more deeply plicated and along the mar— gin interlocks downward with the lower valve rather than turning upward along the margin and fitting into the scalloped margin of the lower valve. Adult shells of O. angelica attain a much greater size and thickness than forms of 0. lurida. “These same shell characters serve to separate 0. angelica from O. palmula Carpenter, with which it occurs in the Gulf of California. “The valves of O. angelica are generally larger, thicker, and more deeply plicated than those of O. vespertina. The plications on the exterior of the valves usually are present only on the distal half or third of the valves of 0. angelica. On the lower valve these plicae extend from the margin to the broad unplicated area of attachment. The corresponding area of attachment on O. vespertina is usually much smaller. Furthermore the upper valve of O. angelica is more convex, the plications interlock downward along the margin, whereas on O. vespertina the upper valve is almost flat and fits into the scalloped edges of the lower valve similar to that of O. lurida laticaudata and O. palmula.” (Hertlein and Grant, 1972, p. 217) Comments—The posterior half of the left valve of Dendostrea? angelica rises vertically from the substrate, a generic character used by Stenzel (1971, p. N1 109-N1110) to differentiate the genus Neopycno— donte. In other characters, however, D.? angelica is closest to T TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE C27 Dendostrea. According to Harold W. Harry (written commun., 1983), its anatomy is distinctly lophine. Geographic range—Living: Golfo de California; fossil: southern California to Mexico. Geologic range—Miocene or Pliocene to Holocene. Occurrence in the Californias.—Mi0cene or Pliocene: Imperial For— mation (Stump, 1979); Pliocene: Almejas (Minch and others, 1976), Carmen (Durham, 1950), Infierno (McFall, 1968), Marquer (Durham, 1950), and San Diego (Hertlein and Grant, 1972) Formations; Pleistocene: unnamed strata in Baja California Sur (Durham, 1950) and Mexico (Stump, 1979). Habitat—At the mouths of estuaries and bays that are sheltered from breakers but which have a current (Hertlein and Grant, 1972, p. 217). From 1-5 m and 13-32 °C (Bernard, 1983, p. 24). Subfamily OSTREINAE Left valve often plicate, right valve usually less so, with much variation among individuals. Chomata are a single band of pustules in the right valve with pits to receive them in the left valve (Harry, 1983, p. 90). Chomata are small, few, generally present in small shells, often absent in larger ones. Chalk deposits usually present, not vesicular. Attachment small to large; no hyote or clasper spines. (Harold W. Harry, written commun., 1983) As restricted by Harold W. Harry (written commun., 1983), Ostrea s. 3. includes those species that have smooth surfaces or closely spaced, thin, fragile imbricated lamellae on the flat right valve which has no radial ribs. The left valve has fewer growth rests than the right valve, the lamellae are fewer and thicker and narrower but more elevated. The left valve has numerous, closely spaced, small radial plicae, more or less continuous at growth rests. The attachment area is small to large. Genus OSTREA Linné, 1758 Very compressed circular shells with no plications along valve mar- gins. Chomata often absent in large specimens (Harry, 1983, p. 90). Genus here restricted to those species which have numerous, closely spaced, thin, fragile imbricated lamellae on the right valve. The right valve is flat and lacks radial ribs; the left valve has numerous closely spaced, small radial plicae. Chalk deposits are usually present. (Harold W. Harry, written commun., 1983) Geographic range—Eastern Atlantic, Indo-West Pacific, Japan and adjacent Asiatic coast. No species of Ostrea s. s., as here restricted, is known living in the northern hemisphere of the eastern Pacific or western Atlantic. Ostrea edulis (Linné) is present in the eastern Atlantic and Ostrea denselamellosa Lischke is present off Japan and the adjacent asiatic coast. Besides the typical subgenus, a second one, Eostrea Ihering, 1907, is represented by a single living species, 0. (E.) puelchana Orbigny, circum-mundane between 35° and 50° S. latitude. Adult shells of the two subgenera are practically the same, and only differences in larval form and period of incubation distinguish the two. (Harold W. Harry, written commun., 1983) Geologic range—Cretaceous through Holocene (table 8). Habitat. —In cool, temperate waters, most populations live at a depth of several meters, but a few specimens are found at very low tides. (Harold W. Harry, written commun., 1983) Open sea and bays in salinity of 22-41 parts per thousand (Oyama, 1952, p. 338). TABLE 8.—Geotogic and geographic distribution of the genera Ostrea, Ostreola, “Ostrea,” and Acutostrea in the eastern Pacific region [H=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; OzOligocene; Eoncene; Pa=Paleocene} Species Alaska British Wash— Oregon California Baja California. Central Columbia ington North or South ern Middle Southern Norte Sur America Genus Ostrea Subgenus Ostrea atwoodii Gabb.. ------------------------- Genus Ostreola conchaphila (Carpenter) ...... H H H H H Genus Ostreola? venturana (Loel and Corey) ................................ megodon (Hanley) .................................... Genus “Ostrea” weaveri Dickerson ............................. Pa Genus Acutostrea idriaensis fettkei (Weaver) .................... E ---------- idriaensis idriaensis (Gabb) ................... E E ..... simiensis M and PI M and Pl """""""" P1 to H P1 to H P] to H H H ..... O and M ----- M or P1 to Ple P1 and Pie P1 to H Pa .................... Pa and E (Zinsmeister)... .............................. Pa ............... Genus Acutostrea? miguelensis (Hertlein) ....................................... C28 Subgenus OSTREA Ostrea (Ostrea) atwoodii Gabb Plate 30, figures 7, 9 Ostrea atwoodii Gabb, 1866, p. 33-34, pl. 10, figs. 58, 58a; pl. 11, fig. 58b. Arnold, 1909, p. 140, pl. 17, figs. 1, 2. Woodring in Woodring and others, 1940, p. 92, pl. 29, figs. 1, 13. Durham and Addicott, 1965, p. A13, pl. 3, figs. 3, 7. Addicott in Addicott and Galehouse, 1973, fig. 3p, r. Original description—“Shell broad, irregular, thin; partly attached, sometimes by nearly the whole of the lower surface; free surface of lower valve marked by numerous irregular radiating ribs crossed by lines of growth; upper valves more squamose and not radiated (in the only specimen I have seen). Hinge broad at the base, triangular, not deep, and sometimes slightly oblique; inner margin of the shell not denticulated. Muscular scar broad.” Holotype.—Missing (Keen and Bentson, 1944). Type locality—San Lorenzo Creek, Monterey County, Calif. Pancho Rico Formation, Miocene. Comments—The smooth, flat right valve and the finely ribbed left valve serve to distinguish O. atwoodii. Geographic range—Middle and southern California. Geologic range—Miocene and Pliocene. Occurrence in California—Miocene: Pancho Rico Formation (Durham and Addicott, 1965); Miocene and Pliocene: Etchegoin For- mation (Woodring and others, 1940; Adegoke, 1969); Pliocene: Paso Robles Formation (Addicott and Galehouse, 1973). Genus OSTREOLA Monterosato, 1884 Stenzel (1971, p. N1138) placed Ostreola in synonymy with Ostrea. Ostreola is reinstated here and the information concerning the genus was furnished by Harold W. Harry (written commun., 1983). Shells smaller than those of Ostrea, as restricted herein; generally subcircular to slightly elongate dorso-ventrally. The right valve is flat, or nearly so, without radial plicae, and the prismatic layer is continu- ous as a smooth sheet with few growth rests from which no lamellae project. Left valve often broadly cemented to substrate, but upturned part usually has prominent plications. Ostreine chomata prominent, extensive, and persistent in older shells. Geographic range—Mediterranean and probably southward in the eastern Atlantic at least to the equator; western Atlantic from North Carolina to Argentina; eastern Pacific from Alaska to Panama. Geologic range—Oligocene (?); Pliocene to Holocene (table 8). Habital.—Stenohaline, oceanic salinity. Of the three species known living, two extend from the tropics to the cool temperate zone and the third may have the same range, but its distribution is poorly known. Occasionally found at very low tide level, but optimum populations are found subtidally at a depth of a few meters. Ostreola conchaphila (Carpenter) Plate 30, figures 1-4, 6, 8 Ostrea conchaphila Carpenter, 1857, p. 161-163. Palmer, 1958, p. 66 [see for synonymy]. Ostrea lurida Carpenter, 1864, p. 645. Arnold, 1909, p. 167, pl. 30, fig. 12. Oldroyd, 1924, p. 50, pl. 37, figs. 10a, 10b. Howard, 1935, pl. 7, fig. 5. Palmer, 1958, p. 66-67, pl. 5, figs. 4-6. Hertlein, 1959, p. 6-7, pl. 2, figs. 1-3,6-9,11. Original description—“0t. plerumque parva, tenui, subovali, tes- tis variis affixa; purpurea saepe aurantia tincta, interdum radiis una PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA vel duabus; cardine parvo, utroque latere denticulis crenato; area ligamenti augusta, triangulari, saepius sulco denticulato utraque parte extus ornata; plerumque tota valva affixa, margine integro, sed interdum subiter ascendente, margine undato, vix plicato; intus sub- nacreo, cicatrice modico, irregulari.” (conchaphila) “T. omnino planata, per totum superficiem affixa; extus, marginem versus laminata, purpureo radiata; intus, olivaceo-rufa, ligamento parvo, in medio undato, solidiore. “Animal flavore cupreo tinctum. “Var. laticaudata, Nutt. ms.: t. omnino purpurea, margine producto, undato; cardinem versus, denticulis conspicuis instructo.” (lurida) Holotype.—BM(NH); of lurida, syntypes Redpath Museum 125. Type locality—Mazatlan, Mexico, of lurida, Shoalwater, Willapa Harbor, Washington (Palmer, 1958, p. 67). Supplementary description.—“Ordinarily it is a very small purple shell, frequenting other shells even when living, and often interfering with their growth. It is known by the very small triangular ligament area, with very fine denticles on each side. In addition to these, there are generally (in the attached valve) two lines of denticles situated in furrows running outside the area to the umbos. It begins life as a swollen regularly formed body, of the shape of Astarte compressa. A specimen from S.W. Mexico, in a dead Cypraea, retains this regularity and general form: it is smooth, white, and convex. The hinge of the attached valve, when extremely young, reminds one of Mesodesma; the ligament being internal between two raised processes followed by pits; the processes afterwards developing into the ligamental area. Sometimes the shell becomes rather thick, and, after continuing smooth and flat, suddenly rises, and waves (almost plicating) the outer margin.” (Carpenter, 1857, p. 162) “This is a rather small species of an irregular ellipsoidal or elongate shape, sculptured with crude, low, irregular plications, or almost smooth except for irregularities of growth." (Grant and Gale, 1931, p. 151) “Valves thin, irregular in shape, usually circular or elongate, some- times scalloped at the edges. Surface of both valves flat though may conform to contours of substrate.” (Fitch, 1953, p. 38) “The lower (left) valve, shallowly concave, may be attached by a small area beneath the umbo or attached by the entire surface. The upper (right) valve is flat and fits into slightly raised margins of the opposite valve. Several small denticles are present along the margin just anterior to the hinge area ***.” (Hertlein, 1959, p. 6) Comparison—“Adult shells of O. angelica Rochebrune attain a much greater size and thickness than forms of O. lurida.” (Hertlein and Grant, 1972, p. 217) “The smaller size is the only apparent character that distinguishes elongate, weakly plicate left valves, and most right valves, of Ostrea vespertina sequens Arnold from moderately elongate shells of O. lurida.” (Woodring, 1938, p. 44) ' Geographic range—Living: Alaska to Panama, especially common in Willapa Bay and Puget Sound, Washington; fossil: middle Califor- nia to Baja California Norte. Geologic range—Pliocene to Holocene. Occurrence in the Californias.——Pliocene: Almejas (Hertlein, 1933; Minch and others, 1976) and San Joaquin (Howard, 1935; Adegoke, 1969) Formations; Pliocene and Pleistocene: Fernando (Kennedy, 1975), Merced (Martin, 1916; Glen, 1959), and Saugus (Kew, 1924) For- mations; Pleistocene: Anchor Silt (Rodda, 1957), Bay Point Formation (Kern and others, 1971), Carlotta Formation (Ogle, 1953), Medill Sand (Rodda, 1957), Palos Verdes and San Pedro Sands (Woodring and others, 1946), Timms Point Silt (Woodring and others, 1946), and unnamed strata in coastal southern California (Valentine, 1956), on San Nicolas Island (Vedder and Norris, 1963), and in Baja California N orte (Valentine, 1957). Habitat—“In the Pacific Northwest it is found in beds on the sur- face of mud flats and gravel bars near the mouths of rivers or streams. TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE C29 In other localities it is found in most sheltered inlets and bays along the entire coast, attached to the shells of previous generations of oysters or any firm surface that will hold it out of the mud. These beds may cover several acres and are usually exposed at low tide. Often when not in beds these oysters are found singly or in small clusters attached to rocks, cement pilings and particularly to metal buoys, floats, etc.” (Fitch, 1953, p. 38) Spawns at minimum temperatures of about 14 to 16 °C (Hopkins, 1936, p. 460). Intertidal to 50 m (Bernard, 1983, p. 23). Genus OSTREOLA? Ostreola? venturana (Loel and Corey) Plate 31, figure 7; plate 33, figure 5 Ostrea venturana Loel and Corey, 1932, p. 193, pl. 15, fig. 2; pl. 18, figs. 1, 2. Original description—“Shell small, thin, ovate-pointed; lower valve moderately convex with no ornamentation other than fine incre- mental lamellae. In another specimen the interior of the lower valve is seen to be deep, muscle scar central and reniform, margins thin and finely serrate, and hinge area is triangular with narrow, deep liga- ment pit. Upper valve of another individual is convexo-concave or flat, with broad hinge area lower than in lower or right valve. Height, 12 mm.; width, 6 mm.” Holotype.—UCMP 31751. Type locality—U0 A-321. Santa Barbara County, Calif. Vaqueros Formation, Oligocene and Miocene. Comparison—“Ostrea venturana *** resembles O. lurida *** in form, and may be ancestral to it, but is distinct in its constant smaller size and ovate-pinnate shape, lack of ornamentation, elongate- reniform muscle scar, and serrate margins. The present discussed species is distinct in shape and in its lack of medial ridge from 0. miguelensis Hertlein, the only other small Ostrea known from the Vaqueros horizon.” (Loel and Corey, 1932, p. 193) Geographic range—Southern California. Geologic range.——Oligocene and Miocene. Occurrence in California.—Oligocene and Miocene: Vaqueros For- mation (Loel and Corey, 1932; Weaver and Kleinpell, 1963). Ostreola? megodon (Hanley) Plate 32, figure 2, 5; plate 34, figures 1, 3, 6, 8 Ostrea megodon Hanley, 1846, p. 106. Jordan and Hertlein, 1926b, p. 427-428, pl. 28, fig. 1. Durham, 1950, p. 59, pl. 5, fig. 3. Ostrea (Lopha) megodon Hanley. Keen, 1971, p. 84, fig. 173. Ostrea (Agerostrea) megodon Hanley. Hertlein and Grant, 1972, p. 221-222, pl. 38, figs. 1, 5, 7. Smith, 1984, p. 206, pl. 4, figs. 1, 2. Agerostrea megodon (Hanley, 1846). Bernard, 1983, p. 23. Ostrea cerrosensis Gabb, 1866, p. 35, pl. 11, fig. 61. Ostrea megodon Hanley subsp. cerrosensis Gabb. Stewart, 1930, p. 130, pl. 14, fig. 1. Not Ostrea (Alectryonia) megodon Hanley of Olsson, 1964, p. 39, pl. 1, figs. 1-1b[= O. messor Maury, 1925]. Original description.—“Ost. Testa falcata, glabra, solida, subae- quivalvi, pallide livido-purpurascente, margines versus plicata; plicis anticis 5 aut 6, maximis, subangulatis; posticis minimis, angulatis, paucis sub—obsoletis; margine valde plicato, intusque magis minusve scabro; natibus incurvatis; superficie interna albo-virescente, nun- quam margaritacea; cicatrice satis magna, reniformi. Long. 5 poll.” (megodon) “Shell small, subequivalve, very oblique, strongly falcate, variable in form, upper edge entire, concave; lower margin very strongly undu- lated, each valve bearing four or five rounded, tongue-like processes, which alternate in the two valves; the margin, on each valve, between these processes, is very much thickened, and presents the squamose edges of successive layers of growth. Surface smooth, or marked only by rather indistinct lines of growth. Hinge long and very oblique, slightly curved. Muscular scars small, rounded subtriang‘ular.” (cer- rosensis) Holotype.—BM(NH). Lectotype of Ostrea cerrosensis ANSP 4494. Type locality. —Peru. Of 0. cerrosensis, Isla Cedros, Baja California Norte, Almejas(?) Formation, Pliocene. Supplementary description.—“Shell elongate arcuate, (length up to 100 mm), the two valves nearly alike, ventral margin folded into three or four large, sharp but short plications, attached generally by a small area on the extreme umbone of the left valve. The dorsal side is concave or excavated, often finely corrugated on the margin. Surface smoothish or roughened by concentric growth incrementals.” (Olsson, 1961, p. 173). Hertlein and Grant (1972, p. 222) noted variation in the development of denticles on the shell margins and in the width and depth of fluting of Holocene specimens of 0.? megodon. Comments—The shells of the fossil specimens identified as 0.? megodon are half the size of Holocene specimens. Although this spe- cies bears a striking resemblance to the Cretaceous genus Agerostrea Vyalov, 1936 (Stenzel, 1971, p. N1158-N1160)), it differs from that pre- sumedly lophine genus in having fewer marginal undulations; more- over these undulations are all limited to the antero-ventral margin and more rounded than those on Agerostrea. The anatomy of Ostreola? megodon is ostreine, not lophine. (Harold W. Harry, written commun., 1984) Geographic range—Living: Baja California Sur to Peru; fossil: southern California to Mexico. Geologic range—Miocene or Pliocene through Holocene. Occurrence in the Californias.—Miocene or Pliocene: Imperial For- mation (Stump, 1979); Pliocene: Almejas (Minch and others, 1976), Carmen (Durham, 1950), Gloria (Wilson and Rocha, 1955), Lomita Marl (Woodring and others, 1946), San Diego (Hertlein and Grant, 1972), San Marcos (Durham, 1950) Formations and unnamed Pliocene strata on Isla Tres Marias (Jordan and Hertlein, 1926a); Pleistocene: unnamed strata in southern California (Kanakoff and Emerson, 1959) and in Baja California Norte (Valentine, 1957). Habitat—From 5-20 m and 10-31 °C (Bernard, 1983, p. 23). Subfamily OSTREINAE, incertae sedis “Ostrea” weaveri Dickerson Plate 29, figure 2 Ostrea weaveri Dickerson, 1914, p. 127-128, pl. 9, fig. 3. Original description.—“Shell medium in size, subequivalve, irreg- ularly oval, contorted near the beaks, unattached. Surface marked by regular squamose lines of growth. Beak twisted and terminating at the anterior dorsal margin. The upper half is subglobose while the lower half is flat or slightly concave. These two portions are very deeply set off and the species is readily determined by this characteristic. In the lower valve, the bulging of the upper portion is less prominent. The growth lines are remarkably even for this genus.” Holotype.—UCMP 32624. Type locality. —UC 781. Vicinity of Lower Lake, SEV4, NEV4, T. 12 N ., R. 7 W., Lake County, Calif Martinez Formation, Paleocene. Comments—The holotype is a single worn valve with only the exterior exposed. It is smooth and much inflated for its size on the dorsal half and flat to concave on the ventral half with prominent C30 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA concentric shell lamellae. “Ostrea”weaveri in profile somewhat resem- bles “Quadriostrea”Vyalov (1936, p. 18), from the Cretaceous in Africa, which Stenzel (1971, p. N 1169) considered an uncertain genus. Geographic range—Northern and middle California. Geologic range—Paleocene. Occurrence in California. —Paleocene: Martinez Formation (Dickerson, 1914). Subfamily CRASSOSTREINAE Though the three genera included here tend to be elongate dorsa- ventrally, they are often oval or even round. The right promyal passage is open but smaller than it is in Pycnodonteinae. They tend to live in shallower water than all the other oysters. Their shells are very erodable but they are thickened in several ways. Chalk and conchyolin deposits are common. Plication of left valve is rare (except in Sac- costrea) and even more rare on right valve. Ostreine chomata are usually present, but absent throughout life in Crassostrea. Attach- ment absent throughout life in Crassostrea. Attachment area small to large; hyote spines absent, except in juveniles of Saccostrea, where they are variably present. Left valves sometimes enormously thick- ened, especially in Saccostrea and Striostrea. (Harold W. Harry, writ- ten commun., 1983) Genus ACUTOSTREA Vyalov, 1936 Medium-sized (as much as 9 cm. high); outline variable, mostly elongate—spatulate, straight, or more commonly falcate; subequivalve t0 inequivalve. Left valve beak commonly pointed, straight or vari- ously curved, projecting beyond that of right valve; ligamental area acuminate, high triangular, length of resilifer commonly twice that of adjoining bourrelet; deep umbonal cavity overhung by hinge plate. Left valve commissural shelf with rounded gutter in which pits of chomata are located. Left valve with many undulatory growth squamae and in some individuals few (about 6) wide low weak radial costae. Right valve lacks costae but has concentric growth squamae. (Stenzel,1971) Kiyotaka Chinzei (written commun, 1983) first suggested that I consider the genus Acutostrea for the included species. The genus previously was known only from the Upper Cretaceous. Geographic range—Europe and North America. Geologic range—Cretaceous to Eocene; Oligocene and Miocene(?) (table 8). Acutostrea simiensis (Zinsmeister) Plate 34, figures 4, 5 Ostrea simiensis Zinsmeister, 1983, p. 1286—1287, fig. 1E-G. Original description—“Shell medium to small gryphaeiform; left valve narrow, but occasionally moderately broad; beaks medium- sized, blunt, prosogyral to nearly orthogyral; somewhat enrolled with small attachment area; left valve smooth with infrequent low con- centric undulations; poorly developed radial sulcus; right valve flat to slightly concave with faint squamae.” Holotype.—UCR 6899/101. Type locality.—UCR 6899. Ventura County, Calif, Simi Con- glomerate, Paleocene. Supplementary description—“This species is easily recognized by its narrow, elongated outline and small to medium size." (Zinsmeister, 1983) Comparison—“O. simiensis n. sp. is similar to O. haleyi Hertlein from the Eocene, but is not quite as narrow and the beak is more prosogyral. The close similarity of the two species suggest that O. simiensis n. sp. may be ancestral to 0. haleyi. The only other oyster (O. weaveri Dickerson) occurring in the upper Paleocene of the Simi Hills can easily be distinguished by its larger size and coarse, evenly spaced squamae.” (Zinsmeister, 1983) Geographic range—Southern California. Geologic range—Paleocene. Occurrence in California—Paleocene: Simi Conglomerate (Zinsmeister, 1983). Acutostrea idriaensisfettkei (Weaver) Plate 30, figure 5; plate 32, figures 4, 6; plate 33, figures 1-3, 8 Ostrea fettkei Weaver, 1912, p. 30, pl. 4, figs. 37, 39. Ostrea idriaensis (?var.) fettkei Weaver. Vokes, 1935, p. 291. Ostrea idriaensis Gabb var. fettkei Weaver. Vokes, 1939, p. 54-55, pl. 2, figs. 11, 13. Ostrea crandalli M. A. Hanna, 1927, p. 275, pl. 29, figs. 1, 2. Ostrea buwaldana Dickerson, 1914, p. 127, pl. 9, fig. 4. Original description—“Shell small, thin, somewhat curved, right valve nearly flat, left valve convex; hinge deflected to the left and median groove very well marked; internal margins in both old and young forms are pitted; shell inequivalve and slightly inequilateral; left valve ornamented by a marked median ridge extending from beak to basal margin; anterior to this ridge are two radiating ribs becoming obsolete toward the beaks; posterior surface with six radiating ribs extending to the beak; these are crossed by a large number of con— centric ribs and lines of growth.” (fettkei) “Shell of medium size or less, roughly trigonal to pyriform, as figured; beak acute, not curved; thin, with six large well rounded unequal sized ribs which are separated by deep round-bottomed inter- spaces; crossed by prominent growth lines which become rough lami- nae on the ribs; valve slightly distorted below the beak; inner margin crenulate, corresponding to the ribs and interspaces of the outer surface; hinge margin trigonal, slightly rounded internally, central depression narrow, relatively shallow, bordered on either side by an area which appears rough due to the presence of three rounded tooth- like elevations; submargins not denticulate; interior smooth; adductor scar marginal, more sub-circular than the figure would indicate. Dimensions: Altitude 30 mm., length 43 mm., diameter 15 mm.” (cran— dalli) “Shell, medium, with thick shell substance, only slightly oblique, elliptical; upper valve flat; lower valve deep, convex and marked by rough, squamose growth lines and about six strong radiating ribs. Muscular scar is reniform, nearly central. Internal margins of some specimens distinctly pitted on both sides of beaks in casts of this species. Occasionally small tooth-like projections are seen on the shell itself on both sides of the beaks.” (buwaldana) Holotype.—CAS 479; of crandalli UCMP 31072; of buwaldana UCMP 11719. Type locality—One and one-half miles east of Vader on north bank of Cowlitz River in sec. 27, T. 11 N., R. 2 W., Cowlitz County, Wash- ington. Cowlitz Formation, Eocene; of crandalli UC 3981 San Diego County, Calif, Delmar Formation, Eocene; of buwaldana UC 790, Lake County, Calif, Martinez Formation, Paleocene. Comparison.—“Ostrea fettkei Weaver represents a variety of Ostrea idriaensis bearing definite ribs which are of primary strength and not interrupted by the growth-lines . The specimens from the New Idria region are all larger than those from the Washington localities.” (Vokes, 1939, p. 54-55) Comments—The holotype of Ostrea buwaldana is a badly worn specimen and is assumed to be a left valve. Only the internal shell layers are preserved and they show fairly large, radial ribs. Vokes (1935, p. 292), in his description of idriaensis, said that there is a tendency toward the development of a radial type of ribbing but that i» TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE this is always a secondary feature superimposed upon and interrupted by the lamellae. Geographic range—Washington to southern California; Kamchatka(?) (Pleshakov, 1939). Geologic range—Paleocene and Eocene. Occurrence in California.—Paleocene: Martinez Formation (Dickerson, 1914); Eocene: Avenal Sandstone (Vokes, 1939), Delmar (M. A. Hanna, 1927) and Domengine (Vokes, 1939; Weaver, 1949) For- mations, and La Jolla Group (Vokes, 1939). Acutostrea idriaensis idriaensis (Gabb) Plate 13, figures 2, 3; plate 14, figure 6; plate 16, figure 3; plate 29, figures 3-5 Ostrea idriaensis Gabb, 1869, p. 203, pl. 33, figs. 103b, c, d; pl. 34, figs. 103, 103a. Arnold, 1909, p. 106, pl. 2, figs. 4, 5. M. A. Hanna, 1927, p. 276, pl. 30, figs. 1, 2; pl. 31, figs. 3, 4. Stewart, 1930, p. 126, pl. 8, fig. 3; pl. 17, fig. 1. Vokes, 1935, p. 291-295, pls. 22-24. Turner, 1938, p. 46, pl. 6, fig. 9. Vokes, 1939, p. 54. Givens, 1974, p. 44. Ostrea columbiana Weaver and Palmer, 1922, p. 13, pl. 8, figs. 15, 16. Ostrea oregonensis Packard, 1923, p. 4-6, pls. 1-4. Ostrea haleyi Hertlein, 1933, p. 277, pl. 18, figs. 5, 6. ?Odontogryphaea? haleyi (Hertlein). Givens, 1974, p. 45, pl. 1, figs. 11-13. Original description—“Shell moderately large, oblique, often curved, heavy; lower valve usually deep, more oblique than the upper; hinge straight or deflected to the left, median groove pretty strongly marked; internal margins in the young shell, finely crenulated or pitted towards the beak, this character disappearing to a great extent in the adult. Surface of both valves roughly and very irregularly squamose. Muscular scar reniform to semicircular, and placed dis- tinctly to one side of the middle.” (idriaensis) “Shell large and elongate in outline; right valve very convex and irregular; left valve flat or concave with the anterior end straight dorsally, swinging into the ventral margin with a broad curve which continues ventrally to the posterior ventral end; posterior end with a more or less deep concave area at about one-third of the distance from the dorsal line; shell very thick; surface of the left valve rough and irregular with overlapping laminae; surface of the right valve smoother, the growth lines more regular than those of the left valve; left valve with a glossy, corneous outer layer over which are fine yet conspicuous radiating lines; beaks deflected posteriorly; anterior and posterior margins internally or laterally with coarse transverse grooves.” (columbiana) “Shell large, very thick and irregular; subcircular to subovate in outline; left valve very convex, tumid; right valve opercular-form. Anterior dorsal margin of left valve of type and cotype very regularly rounded, for nearly 180 degrees from the beak; base sloping upwards to the slightly attenuated but evenly rounded posterior end. Umbone of type very prominent, strongly curved inward and backward and terminating in a sharply pointed, slightly twisted beak. In both spec- imens the beaks lie well within the margin of the shell. The beak of the cotype is deformed by a large, linear scar of attachment which shows the external mold of a gastropod. An indistinct umbonal ridge extends in a curve, anteriorly, for about half the distance to the anterior extremity. The outline of the flat upper valve of the type is nearly elliptical, much thinner, than the lower one and only slightly convex. Umbone depressed; beak small, twisted slightly posteriorly and situ- ated well within, but not far from the margin of the shell. Surface of left valve marked by heavy concentric imbricating growth lamellae which are irregularly nodose, tending to be radially arranged on the umbone. The growth lamellae of the right valve are thin, ridge-like and lack the nodose character of the left except at the very apex where faint radiat- ing costae may be seen. C31 “Interior of left valve with a broad shallow irregular ligamental groove, slightly depressed near and parallel to the margin of the shell; lateral margins of hinge and valve pitted or crenulated, the crenula- tions extending on either side nearly to the base. Adductor scar impressed, situated posterior to the center.” (oregonensis) “Shell elongate, rounded umbos, broader toward the base; beak curved inward and backward; a shallow groove extends from near the beaks to the ventral margin of the shell where it is more pronounced; a well-defined ligament pit is present beneath the beak. Altitude 45.5 mm.; approximate longitude (shell not complete) 32.5 mm.” (haleyi) Holotype.—Lectotype of idriaensis MCZ 15048 (Stewart, 1930); of columbiana, missing and presumed lost; of oregonensis U0 20; of haleyi CAS 5526. Type locality—About 3 km east of Hacienda at the New Idria [Priest Valley Quad, N1/2 sec. 15, T. 17 S., R. 12 E., San Benito County, Calif], Domengine Formation, Eocene. Of columbiana UW 160A, Cowlitz County, Wash. Cowlitz Formation, Eocene; of oregonensis U0 130, Douglas County, Oregon, Umpqua Formation, Eocene; of haleyi Can- ada del Pozo, Santa Cruz Island, Santa Barbara County, Calif. Can- ada(?) Formation, Eocene. Supplementary description.—“The characters which appear to be diagnostic for Ostrea idriaensis Gabb are: 1. Valves discrepant in size; the lower much larger than the upper. 2. Shape variable; umbos generally straight or twisted to the left,but may be slightly twisted to the right. 3. Valves elongate and broader near the base. 4. Lower valve with rugose, coarse, concentric lamellae of growth, a superimposed radial ribbing commonly present; upper valve with finer lamellae of growth, ribbing not present. 5. Lines on the sides of the upper valves near the umbos, reflecting the denticulations present on the lateral margins of the body area of the shell, 6. Ligamental area of the lower valve consisting of a well-marked median groove with two prominent ridges, one on each side, which are bounded by small, linear, lateral grooves at the edges of the area. 7. Ligamental area of the upper valve with a median groove, and two lateral grooves complementary to the ridges of the ligamental area of the lower valve. 8. Ligamental area commonly twisted to the left, but may be straight or slightly twisted to the right. 9. Denticulations present on the lateral margins of the body area of the upper valve near the ligamental region, fitting into pits on the lateral margins of the body area of the lower valve. 10. Left margin of the lower valve commonly with an impressed area into which a corresponding protuberance on the upper valve is fitted. 11. Muscle scar reniform to subcircular; situated approximately one- sixth of the distance across the body area from the left side.” (Vokes, 1935, p. 295) Adult specimens show a great variation in size. Vokes (1935, p. 292) noted that adult left valves range from 65 to 92 mm in height, 50 to 61 mm in length, and 26 to 34 mm in thickness; adult right valves range from 61 to 64 mm in height, 50-53 mm in length, and 14to 21 mm in thickness. Comparison.—In O. idriaensis radial ribbing may develop but it is a secondary feature superimposed upon and interrupted by lamellae, whereas in O. idriaensis fettkei some of the radial ribs become a primary sculptural feature and are little interrupted by growth lamellae. (Vokes, 1935, p. 292-293) The two linear lateral grooves in the ligamental area of O. idriaensis are never as strongly developed as they are on O. stewarti M. A. Hanna, and the muscle scar on the left side of the body area is never so circular as on O. stewarti. (Vokes, 1935, p. 293, 294) Geographic range—Washington to southern California. C32 Geologic range—Eocene. Occurrence in California.——Eocene: Avenal Formation (Vokes, 1939), Canada Formation (Doerner, 1969), Coldwater Sandstone (Weaver and Kleinpell, 1963), Delmar(M. A. Hanna, 1927), Domengine (Vokes, 1939; Givens, 1974), and Juncal (Givens, 1974) Formations, La Jolla Group (M. A. Hanna, 1927), Matilija Sandstone (Givens, 1974), Sacate (Dibblee, 1950), and Tejon (Givens, 1974) Formations. Genus ACUTOSTREA? Acutostrea? miguelensis (Hertlein) Plate 33, figures 4, 6, 7, 9 Ostrea miguelensis Hertlein, 1928, p. 146, pl. 23, figs. 3-6. Loel and Corey, 1932, p. 191, pl. 10, figs. 2a, 2b, 3a, 3b. Original description—“Shell small; obliquely subovate, beaks pointed; shell fairly thick, Lower valve convex, a slight groove runs from beak to umbo, two or three irregular projections of shell material are irregularly scattered on valve, ornamentation consists of fine lamellar edges of shell. Upper valve gently concave with a small raised median ridge which runs from the beak for one third the length of shell, otherwise ornamented only by the incremental shell lamellae. Height from beak to base, 21.5 mm.; greatest anterior-dorsal width, 21 mm.; convexity of valves, 9.1 mm.” Holotype.—CAS 4121. Type locality—GAS 1163. San Miguel Island, Calif. Vaqueros For- mation, Oligocene and Miocene. Comparison.—“Ostrea miguelensis is distinct through its posses- sion of a narrow medial plication effecting [sic] both valves.” ( Loel and Corey, 1932, p. 191) “This small oyster *** in many of its features seems to resemble O. idriaensis Gabb, from the Upper Eocene but it is much smaller and commonly possesses a median ridge on the upper valve. 0. miguelensis resembles the early part of O. bourgeoisii Remond, from the Upper Miocene of California but is more ovate and does not attain a large size; many of the specimens are not ornamented except for the incremental lines of growth. In some specimens the beaks turn anteriorly, in others posteriorly; apparently the direction depends upon the position assumed at the time of attachment. The raised median ridge on the upper valve appears to be an unusual feature in this interesting little shell.” (Hertlein, 1928, p. 146) Comments—Although I am reasonably satisfied with the generic placement of miguelensis, I have queried the generic assignment because neither of the small double—valved syntypes has the interior of the valves exposed. Geographic range—Southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros For- mation (Hertlein, 1928; Loel and Corey, 1932). Genus SACCOSTREA Dollfus and Dautzenberg, 1920 Small to medium—sized, outline variable. Left valve with large attachment area; radial ridges on upturned part. Umbonal cavity usually very deep. Right valve flat, free of folds, but has many scaly growth squamae. Both valves usually have strong chomata which commonly encircle entire valve. Conchyolin deposits abundant. Exte- rior usually very eroded; contour pattern usually present on right valve. Differs from Crassostrea in its deeper umbonal cavity, strong chomata, and tendency to conical rudistiform or cornucopialike shapes. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Geographic range—Nearly circumglobal in the tropics; but absent among living oysters in the western Atlantic. Geologic range—Miocene to Holocene (table 9). Habitat.—Chiefly intertidal, mostly on noncalcareous rocks in surf zone. Occasionally on mangrove in high salinity zone. Saccostrea palmula (Carpenter) Plate 18, figures 1-6 Ostrea ‘2? conchaphila, var. palmula Carpenter, 1857, p. 163-164, 550. Ostrea palmula Carpenter. Keen, 1971, p. 84, fig. 174. Original description—O. ?? conchaphila t. satis magna, margine subito ascendente, valva inferiore superante, undulato, limbo pur- pureo scu olivaceo irregulariter tessellato; linea pustularum valva superiore, in parte nacrea a margine remota, circumeunte, in puncta convenientia valva inferiore aptante; pagina interna subnacrea, aurantio seu purpureo tincta; rarissine spinis ramosis paucis, tabulis ad marginum exteriorem arborescentibus. Holotype.—BM(NH). Type locality—Mazatlan. Supplementary description.—“Remarkable for the palmated folia- tions in the outer margin, which has a distinct limb mottled with purple and olive; and for the row of denticles within this limb and within the nacreous border, fitting into corresponding depressions in the other valve,” (Carpenter, 1857) “One of the most variable of the Panamic province oysters, this may be recognized by the flat or even concave upper valve that fits down into the plicate margins of the cup-shaped lower valve'*** .” (Keen, 1971, p. 84) Comparison—“Modern shells *** of 0. palmula Carpenter, resem- ble ovate or ovate—falcate specimens of the coastal Uespertina in size, but they have an exceptionally long strongly fluted area on the inner margin.” (Woodring, 1938, p. 44—45) According to Woodring (in Woodring and Bramlette, 1950, p. 85) S. palmula has more numerous plications and is considerably smaller than Dendostrea vespertina. Comments—Saccostrea palmula has an exceptionally large attach- ment area, obliterating all but the commissure on some left valves, and the posterior half of the left valve rises vertically from the attach- ment area. The unattached valve fits snugly down into the attached valve. Geographic range—Living: eastern Pacific tropics and Galapagos Islands; fossil: southern California to Baja California Sur. Geologic range—Miocene or Pliocene to Holocene. Occurrence in the Californias.— Miocene or Pliocene: Imperial For- mation (Stump, 1979); Pliocene: Pico (Waterfall, 1929) and Salada (Beale, 1948) Formations. Genus STRIOSTREA Vyalov, 1936 The hinge line of Striostrea is usually long relative to that of other oysters; the left beak often very large. The shell interior is sub- nacreous and the right valve peculiarly brittle, with flaky splinters left at the fractures. Juveniles have prominent ostreine chomata which are usually reduced or even absent in larger specimens. The numerous fragile, appressed lamellae of the right valve have peculiar fine radial striae on them, but this is best seen on small shells, as the valves become much eroded as they grow. The shells generally grow to pon- derous size (as much as 20 cm high) and usually attach by most of the left valve to firm rocks. The left valve often becomes very thick, by continuous secretion of the foliar layer, and the specimens may be raised thus on pedicels, as high as the maximum dimensions of the shell in profile. Much brown conchyolin is produced in the process, but TERTIARY MARINE PELECYPODS: chalk formation is not as common as in Crassostrea. (Harold W. Harry, written commun, 1983) Differs from Crassostrea by having chomata, a nacreous and irides- cent interior, a very foliaceous shell structure, and a rudistiform growth pattern. Geographic range—North America, east and south Africa, Madagascar, Central America, west coast of Baja California. The eastern Pacific Tertiary species are all questionably assigned to Stria- strea. Geologic range—Eocene to Holocene (table 9). Habitat. —In shallow subtidal waters where there is strong surf and constant oceanic salinity. (Harold W. Harry, written commun, 1983) Genus STRIOSTREA? Striostrea? tayloriana (Gabb) Plate 29, figures 7, 8 Ostrea tayloriana Gabb, 1869, p. 34, pl. 12, figs. 60, 60a. Grant and Gale, 1931, p. 153. Weaver and Kleinpell, 1963, p. 197, pl. 29, figs. 6, 8. Not Ostrea tayloriana Gabb. Jordan and Hertlein, 1926b, p. 428, pl. 33, fig. 3 [= Ostrea erici Hertlein, 1929]. Original description.—“Shell large, thick, irregularly sub- triangular, resembling somewhat some of the more massive forms of O. uirginica; not attached. Surface covered by heavy, irregular, sub- squamose plates, showing more or less of a faint undulation on their edges. Interior unknown. Hinge broad and short(?).” Holotype.—UCMP 12005. Type locality. —San Marcos Pass, near Santa Barbara [NI/2 sec. 21, T. 5 N., R. 28 W., Santa Ynez Quadrangle]. Santa Barbara County, Calif. Gaviota(?) Formation, Eocene and Oligocene. Comments.—The supposed relationship of S.? tayloriana to Crassostrea was first suggested by Gabb, when he commented on its similarity to Crassostrea virginica, and later by Dall (1909, p. 111), when he erroneously synonymized it with Crassostrea titan titan. The holotype is a double-valved specimen with the valves together and closed, thus making the hinge inaccessible. Weaver and Kleinpell (1963, pl. 29, fig. 8) illustrated a left valve of tayloriana, assumed to be correctly identified, and their specimen shows the interior of the shell. PLICATULIDAE AND OSTREIDAE C33 Geographic range—Southern California. Geologic range—Eocene and Oligocene. Occurrence in California—Eocene: Coldwater Sandstone (Bailey, 1952); Eocene and Oligocene: Gaviota Formation (Dibblee, 1950); Oligocene: Alegria Formation (Dibblee, 1950; Weaver and Kleinpell, 1963). Striostrea? appressa (Gabb) Plate 12, figure 3; plate 16, figure 5 Ostrea appressa Gabb, 1869, p. 203-204, pl. 34, figs. 104, 104a. Stewart, 1930, p. 127-128, pl. 13, fig. 1. Original description—“Shell thin, flat, more or less equilateral, valves nearly equal, usually about two-fifths longer than wide. Sur- face covered by numerous, thin, squamose plates. Hinge flat, large; margins simple, sometimes subsquamose. Muscular scar small, oblique.” Syntype.—MCZ 15013 [The best of four specimens labelled in Gabb’s handwriting, according to Stewart, 1930, p. 127]. Missing and pre- sumed lost. Type locality—On one of the branches of Eel River, at the mouth of Salt Creek, southwest of Round Valley, Mendocino County, Calif. Tejon Formation of Gabb (1869) or Temblor Formation of Samuel G. Clark (1940). Supplementary description—“The species is remarkable for its thin, flat shell, often distorted, and for its broad, flat hinge.” (Gabb, 1869, p. 204) “The free valve is convex externally, near the hinge, and concave in the central part *** One specimen retains radial ribs on the external central portion of the valve.” (Stewart, 1930, p. 128) Geographic range—Northern California. Geologic range.—Eocene(?) or Oligocene and Miocene. Gabb (1869, p. 203) wrote, “I found this shell forming a stratum several feet thick, adjoining a bed of coal, and in associated strata were familiar species characteristic of the Tejon Group. “The locality is on one of the branches of Eel River, at the mouth of Salt Creek, southwest of Round Valley ***.” Samuel G. Clark (1940, p. 135) placed Gabb’s type locality (Middle Fork of the Eel River at the mouth of Salt Creek, NE1/4 sec. 11, T. 21 N., R. 13 W.) in the Temblor Formation. He said that in the shale above the TABLE 9.—Geologic and geographic distribution of the genera Saccostrea and Striostrea? in the eastern Pacific region [H=Holocene; P1=Pliocene; M=Miocene; O=Oligocene; E=Eocene] Species California Baja California Central or South Northern Middle Southern Norte Sur America Genus Saccostrea polmulo (Carpenter) ......................................... M? and P1 H P] to H H Genus Striostrea? appressa (Gabb) ......................................... E?, O, and M """"""""""""" bourgeoisii bourgeoisii (Rémond) ................. M M """""""" bourgeoisii perrini (Hall and Ambrose) ........ M """""""""" freudenbergi (Hertlein and Jordan) ................ O and M M M """ subtitan (Loel and Corey) .................... O and M """""""" tayloriana (Gabb) ................................ E and O """""""" C34 coal seam were some oysters and gastropods that F. E. Turner said could be either Miocene or Eocene and that the nearest strata equiv- alent to Gabb’s Tejon was 2.2 km up the river. Because Gabb (1869, p. 203) said that he found appressa adjoining a bed of coal, it seems reasonably certain that the type locality is indeed in the Temblor Formation as mapped by S. G. Clark (1940; locality 56). A Desmostylus tooth was collected, presumably at this same locality, and is in the collections of the California Academy of Sciences (Van— derHoof, 1937). The oldest known geologic record for Desmostylus is late Oligocene, and the genus is common in the Temblor Formation. It seems more likely that C.? appressa was collected from the Temblor Formation than from Gabb’s Tejon, yet it is puzzling that Gabb (1869, p. 203) said he found “familiar species characteristic of the Tejon Group” in associated strata with C.? appressa. Occurrence in California—Oligocene and Miocene: Temblor(?) For- mation (Clark, 1940). Striostrea? freudenbergi (Hertlein and Jordan) Plate 26, figure 3; plate 27, figure 3 Ostrea freudenbergi Hertlein and Jordan, 1927, p. 622, pl. 17, fig. 9; pl. 18, fig. 4. Loel and Corey, 1932, p. 190-191, pl. 14, figs. 1a, 1b; pl. 15, figs. 1a, 1b. ?0strea freudenbergi Hertlein and Jordan. Adegoke, 1969, p. 108, pl. 4, fig. 7; pl. 5, fig. 7. Original description—“Shell elongate, thickness medium, right valve moderately arched, narrow at beak but widening ventrally, made up of flattish layers of shell material which is ornamented by faint, rather small radial plications. Interior of valve under beak possesses a ligament pit which is rather prominent, long, fairly broad and moder— ately impressed; concavity of shell moderately deep, just ventral to ligament pit but becoming flatter toward the ventral margin; ventral muscle scar fairly large, impressed and located on the anterior side of the shell about a third of the length of shell from the ventral margin. Height 88.5 mm.; length 61.1 mm.; greatest diameter 21.1 mm.” Holotype.—CAS/SU 5138. Ripe locality.—CAS/SU 59. “Tbrritella bed above San Gregorio Lagoon, 120 miles [190 km] north of Magdalena Bay *** on the trail from Arroyo Mesquital to La Purisima.” Baja California Sur, Isidro(?) Formation, Miocene. Comparison.—“Ostrea freudenbergi can be distinguished from O. chilensis Philippi and other west coast Ostreas by its only moderately high right valve, elongate shape, faint radial ornamentation, dif- ferently shaped ligament pit and long, narrow beaks.” (Hertlein and Jordan, 1927, p. 622) Comments—One method suggested by Stenzel (1971, p. N995) for distinguishing the right from the left valve on oysters is to draw the mid—axis on a valve. The center of the adductor muscle then falls to the left side on the inner face of the left valve and to the right side on the right valve. If this is done on the holotype of S. ? freudenbergi, it is seen to be a left valve, although it was described as a right valve (Hertlein and Jordan, 1927, p. 622). The left valve holotype of S. .9 freudenbergi is small, relatively thick with faint traces of radial ribs. It is narrow for about half the height of the shell and then widens. The muscle impression is deep and subquadrate. The ligamental area is moderately narrow and the resilifer shallow. The faint radial ribs suggest Striostrea. Geographic range—Southern California to Baja California Sur. Geologic range—Oligocene and Miocene. Occurrence in the Californias.—Oligocene and Miocene: Vaqueros Formation (Loel and Corey, 1932; Vedder, 1973); Miocene: Isidro(?) Formation (Hertlein and Jordan, 1927), Saltos Shale Member, Mon- terey Shale (Vedder, 1973), and Tortugas Formation (Minch and others, 1976). PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Striostrea? subtitan (Loel and Corey) Plate 22, figures 3-5 Ostrea titan Conrad. Arnold, 1907a, pl. 40, fig. 2. Not Ostrea titan Conrad, 1853. Ostrea new species near titan Conrad. Arnold, 1907b, p. 32. Ostrea titan (Conrad)subtitan Loel and Corey, 1932, p. 192, pl. 18, fig. 3. Original description—“There occurs in the Vaqueros horizon an Ostrea species which is identical in all characters with O. titan Conrad except in its constant comparatively greater length in proportion to height (‘wider’ valves) and smaller size. Arnold (10c. cit.) noted this from the Vaqueros of the western Santa Ynez Mountains, where it is associated with a typical Vaqueros assemblage. An Ostrea of very similar form occurs in the Oligocene in this same region. This form is probably ancestral to O. titan Conrad (1853) of Middle and Upper Miocene. The specimen figured is from Univ. Calif. 10c. A326, San Antonio Creek, Ventura County, found associated with Pecten magno— lia, Rapana vaquerosensis, and others characteristic of Vaqueros, Lower Miocene.” Holotype.—UCMP 31750. Type locality.—UC A-326. Ventura County, Calif. Vaqueros Forma- tion, Oligocene and Miocene. Comments.—The holotype is a double-valved specimen with the valves separated. The specimen, poorly preserved, has few dis- tinguishing features except that it has a rounder outline than C. titan and is smaller. The adductor muscle impression is somewhat reniform, suggesting Striostrea. Geographic range—Southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros For- mation (Loel and Corey, 1932); Miocene: Beechers Bay Member (Weaver and Doerner, 1969) and Saltos Shale Member (Vedder, 1973) of the Monterey Formation. Striostrea? bourgeoisii bourgeoisii (Rémond) Plate 25, figure 1; plate 26, figure 5 Ostrea bourgeoisii Remond, 1863, p. 13. Gabb, 1866, p. 33, pl. 11, figs. 57, 57a. Clark, 1915, p. 447-448, pl. 43. Eaton, Grant, and Allen, 1941, p. 240, pl. 3, fig. 1. Hertlein, 1951a, p. 188, fig. 1, no. 1. Original description—“Shell suboval, higher than long, strongly contracted near the cardinal area, sub-rounded on the ventral margin; inferior valve comparatively thin, convex, irregular exteriorly, with remote, somewhat rugose plaits of growth. Ligament fossa long, pro- found, minutely wrinkled and finely striated, oblique and turned downwards; muscular impression very large, oblique, and sub-cen- tral, somewhat prominent.” Holotype.—Location unknown. Remond (1863, p. 13) said that he was describing “two lower valves, from the collections of Mr. l’Abbe Bourgeois (Pont-Levoy, France) and Mr. Bioche (San Francisco)”. Type locality—Vicinity Kirker’s Pass [NV2, sec. 9, T. 1 N ., R. 1 W.], Contra Costa County, Calif. Briones Sandstone, Miocene. Supplementary description.—Takeo Suzuki (written commun, 1982) says that Striostrea? bourgeoisii bourgeoisii is characterized by a thick left valve, which is arched and has a long, narrow, slightly curved resilifer trough, and that the right valve is much flatter than the left and has a narrow, long resilifer. “O. bourgeoisii Rémond somewhat resembles O. titan Conrad in its size and thickness, though it is never as large. The maximum length as measured from the beak through the muscle impression is about eight to ten inches, with a maximum width at right angles to this of about five inches. Both valves vary considerably in thickness; sometimes the shell of the ventral valve has a thickness of from two to three inches. TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE The ventral valve is usually only slightly more convex than the upper valve but is usually somewhat thicker. The fine radiating ridges on the surface, described by Remond, are not constant, appearing on only a few specimens that the writer has seen. "0. bourgeoisii Remond differs from O. titan Conrad in that the ligamental pit is narrower and the ligamental callus is heavier; on Ostrea titan Conrad the ligamental pit extends nearly across the anterior end of the shell; the muscle impression on 0. bourgeoisii Rémond is much smaller and is nearer the posterior end of the shell than on 0. titan Conrad; on the latter species the muscle impression is sometimes nearly half the width of the shell; the ventral valve of O. titan Conrad is usually more strongly convex. A large number of specimens of both species were examined and these differences were found to be constant.” (Clark, 1915, p. 448) One of the oldest oysters, in terms of its life span, as seen by Stenzel (1971, p. N1016), is a specimen of S.? bourgeoisii bourgeoisii from the Temblor Formation (CAS 33269). The ligamental area is 2 cm long and 13 cm high; the apex is missing but the remainder has 43 annual layers. Comparison—“Fragment of lower (left) valve, showing the charac- teristic narrow, commonly curved ligamental pit and uneven, wavy growth lamellae which differentiate this species from 0. titan and 0. titan var. prior. Average adult is about 7 inches long. No specimen observed has much more than half the length of an adult 0. titan; has commonly the length but only about half the mass of 0. titan var. prior. Differs from 0. ligminuta of somewhat similar average length in its much thinner valves, relatively large body cavity, longitudinally curved shell, and uneven growth lamellae, From 0. cierboensis in being highly elongate instead of sub—rounded in outline, in having a narrow, round, and elongate instead of a wide, flattish, and extremely short ligamental pit, and in lacking the broad, somewhat even radial plications of the latter.” (Grant and Eaton in Eaton, Grant, and Allen, 1941.) Comments.—The fine riblets on some specimens and patches of nacreous shell suggest assignment to Striostrea. Geographic range—Middle and southern California. Geologic range—Miocene. Occurrence in California—Miocene: Briones Formation (Trask, 1922), Branch Canyon Sandstone (Hill, Carlson, and Dibblee, 1958), Cierbo Sandstone (Huey, 1948), Neroly (Hall, 1960), San Pablo Forma- tion (Clark, 1915), and Santa Margarita (Addicott and Vedder, 1963), and Topanga (Kew, 1924) Formations. Striostrea? bourgeoisii perrini (Hall and Ambrose) Plate 26, figure 4; plate 27, figure 5 Ostrea titan Conrad var. perrini Hall and Ambrose, 1916, p. 80-81. Wiedey, 1929a, p. 22, pl. 3, fig. 1. Original description—“Lower valve. Shell irregularly elliptical, contracted at beak; beak curved toward right when viewed from exte- rior; right valve very ventricose; extremely laminated, giving rough plaited surface; left valve almost flat, laminated; muscle-scars dis- tinct; hinge long, narrowing at beak, viewed from interior curves to left; cavity of hinge deep, coarsely wrinkled, with wrinkles running up onto either side of hinge; interior of hinge ends abruptly, cutting at right angles toward interior of shell, although not characteristic of all forms.” Holotype.—CAS/SU 502. Type locality.—Pleasanton Quadrangle, Alameda County, Calif. Briones Sandstone of San Pablo Group, Miocene. Comparison—“This species greatly resembles O. titan Conrad, the main difference between the two being in the hinge. This variety has a long curved pointed hinge, while the 0. titan has a much shorter hinge, about as wide as long. Also the summit of this variety does not rise C35 above the beak of the opposite valve. All forms do not have as curved a hinge as this one figured. It is generally elongate, and seldom, if ever, has the subcircular shape the 0. titan often has.” (Hall and Ambrose, 1916, p. 81) Comments.—The characters given by Hall and Ambrose (1916, p. 81) to distinguish perrini from titan are basically the same as those used to distinguish S. ? bourgeoisii bourgeoisii from Crassostrea titan titan. Certainly the relationship of perrini is with bourgeoisii rather than with titan, and additional material may well prove perrini to be con- specific with bourgeoisii. Geographic range—Middle California. Geologic range—Miocene. Occurrence in California—Miocene: Briones Sandstone, San Pablo Group (Hall and Ambrose, 1916). Genus CRASSOSTREA Sacco, 1897 Small to very large (to 60 cm high), outline very variable among individuals, but high, slender, spatulate forms with subparallel ante- rior and posterior margins seem most common. Surface rough, right valve with many nonappressed, irregularly spaced growth squamae, simple or frilled along free edges; left valve with poorly developed, discontinuous plicae. Shells very erodable and thickened in several ways. Umbonal cavity usually small. No chomata in post-larval shells. Adductor muscle imprint close to posterior valve margin and closer to ventral margin than to hinge; its outline has two fairly sharp corners and a nearly straight or concave dorsal margin. The validity of the many specific and subspecific names proposed for Crassostrea, especially Miocene forms of C. titan titan, needs special attention. In this work, based almost wholly on type material, the validity of the many names proposed is not always challenged nor are they synonymized. Large collections of Crassostrea from as many different environments as are represented in a single formation span- ning a short time interval need to be carefully studied and compared with living populations of Crassostrea. Logic as well as observation dictates that oysters crowded together will respond to that crowding in their growth form. Stanton (1966, p. 26) has discussed the variability in morphology of C. titan from north to south within the Miocene Castaic Formation. Geographic range—Living along the shores of most continents and of larger islands nearby (Antilles, Borneo, Philippines, Japan) but not south of the equator (Harold W. Harry, written commun., 1983). Geologic range—Cretaceous to Holocene (table 10). Habitat—Mostly in constant brackish water but may live in hyper- saline conditions in the tropics. Usually in shallower water than all other oysters. Intertidal zone and to shallow depths in estuarine conditions, protected from strong wave action but with strong tidal currents. The living species, although essentially tropical, do not seem to live south of the equator, and C. gigas and C. Uirginica extend into temperate and even into cool waters. (Harold W. Harry, written com- mun., 1983) Crassostrea titan (Conrad) Plate 23, figures 1-7; plate 24, figures 1, 3, 4, 6; plate 27, figure 4; plate 28, figures 3, 5; plate 29, figures 1, 6 Ostrea titan Conrad, 1853, p. 199-200. Conrad, 1857b, p. 72, pl. 4, fig. 17; pl. 5, fig. 17a. Arnold, 1907a, p. 543, pl. 45, fig. 2. Arnold, 1909, pl. 5, fig. 1; pl. 10, fig. 5; pl. 11, fig. 2. Clark, 1915, pl. 44, fig. 1. Grant and Eaton in Eaton, Grant, and Allen, 1941, pl. 4, fig. 2. Hanna and Hertlein, 1943, fig. 63-14. Addicott, 1965, p. 0103, fig. 3a. Ostrea titan titan Conrad. Adegoke, 1969, p. 109, pl. 5, figs. 1, 8. Ostrea (Crassostrea) titan Conrad. Ball, 1909, p. 111. 036 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA TABLE 10.—Geolagic and geographic distribution of the genus Crassostrea in the eastern Pacific region lH=Holocene; Pl=Pliocene; M=Miocene; O=Oligocenel Species California Baja California Central or South Northern Middle Southern Norte Sur America Genus Crassostrea columbiensis (Hanley) .......................... M or Pl """ P1 to H H titan (Conrad) ................................... M M """""""" Genus Crassostrea? ashleyi (Hertlein) ............................... O and M M """""""" englekyi (Hertlein) ................................ O? and M """""""" eucorrugata (Hertlein) .......... M M """"" californica osunai (Hertlein). """""""""" Pl “““ uaquerosensis (Loel and Corey) ........ O and M M """"" Crassostrea titan (Conrad). Stanton, 1966, p. 26-27. Stenzel, 1971, p. N973, figs. J14, 1a-lc. Ostrea subjecta Conrad, 1857c, p. 193, pl. 2, fig. 3. Ostrea panzana Conrad, 1857c, p. 193, pl. 2, fig. 4. Ostrea ligminuta Grant and Eaton in Eaton, Grant, and Allen, 1941, pl. 4, fig. 1. Ostrea titan prior Grant and Eaton in Eaton, Grant, and Allen, 1941, pl. 4, fig. 2. Ostrea titan Conrad andersoni Adegoke, 1969, p. 110, pl. 5, figs. 2, 3, 6; pl. 6, fig. 1. Not Ostrea titan Conrad. Arnold, 1907a, pl. 40, fig. 2 l=03trea titan subtitan Loel and Corey]. Original description.—“Elliptical or oblong; extremely thick and ponderous, contracted toward the hinge; ligament cavity profound; upper valve slightly arched; surface coarsely laminated. Length 101/2 inches. Locality, San Luis Obispo, Cal.” (titan titan) “Very irregular, valves sometimes subplicated; cardinal area broad and carinated laterally; cartilage pit but slightly impressed. Locality, between Santa Clara River and Los Angeles Valley, on the Sierra Monica. Height, 2 inches. (in pl. 2 this fossil is improperly included under the 0. panzana).” (subjecta) “Ovate, thick, lower valve with a few lateral distant radiating plicae; upper valve thick, concentrically undulated and rugose; hinge area wide and carinated on the margins. Localities, Panza and Estrella valleys. Height, 23/4 inches. The hinge of this shell resembles that of the preceding [subjecta]; and possibly, it may be the old shell of that species, the specimens of which, in the collection, are evidently all young shells. At Gaviote [Gaviota] Pass specimens of O. panzana occur twice the size of those from the above localities." (panzana) “This species, where previously found, has probably been classified as either an immature 0. titan or an unusually thick»shelled O. bour- geoisii. Averages 6 or 7 inches in length; some specimens attain 9 inches. Ligamental pit, minute in proportion to the exceedingly thick equal valves, averages about 5/8 inches in width, and ranges from 1 to 3 inches in length. 0. ligminuta differs from O. titan in its relatively much narrower, in some individuals curved, ligamental pit, even more prodigiously thick valves, commonly thicker than wide, and normally smaller size. Also, the laminae or shell layers as seen in cross section are strongly curved instead of relatively straight, which gives it its extreme thickness in proportion to width. Then too, the beak is thick, massive, broadly rounded, and in most specimens protrudes beyond the ligamental pit. From 0. bourgeoisii of somewhat similar over-all length and ligamental pit it differs in its extremely thick and massive valves, which are essentially straight instead of curved, its remarka- bly small body cavity, and relatively smooth growth lamellae. It has no resemblance whatever to the ornate, plicated, thin-shelled, large- cavitied O. cierboensis having a broad, short flattish ligamental pit, but is the opposite in all of these attributes. The range of O. ligminuta overlaps that of O. titan var. prior, which latter form, less massive, has the broad, straight ligamental pit, relatively flat laminae, and other characteristics of 0. titan. The average specimen, which is near the holotype in size and medial thickness, has a heavier, more protruding beak than is exhibited by the somewhat worn type. Known range: late upper Briones, and lower and middle Cierbo.” (ligrninuta) “Fragment of upper (right) valve showing convex ligamental callous of O. titan character, and even, flattish growth lamellae at the margins. In nearly all observed respects except size 0. titan. Presumably ancestral to that gigantic Neroly form. Averages 6 or 7 inches in length. Differs from O. titan in having little more than half the length, and thus only a fraction of the mass, of the latter. Since both typical 0. titan and this ancestral variety are commonly found in quantity, the markedly smaller size is quite diagnostic. Where previously observed has presumably been classified as the young of O. titan. Known range: late middle and upper Cierbo.” (prior) “Shell medium, thin, sub-trigonal; composed of many thin, platy calcite layers; valve relatively long, extremely narrow at cardinal area, becomes progressively broader ventrally; shell surface flat or gently concave; ligamental groove and ridge long and relatively narrow, bor~ dered by narrow margins.” (andersoni) Holotype.—Missing and presumed lost; of panzana USNM 13338; of subjecta USNM 13338; ofligminuta UCLA 8985; ofprior UCLA 8991; of andersoni UCMP 36661. Type locality—San Luis Obispo [County], Calif, Santa Margarita Formation, Miocene; of panzana, Panza and Estrella Valleys, San Luis Obispo County, Calif, Miocene; of subjecta, between Santa Clara River and Los Angeles Valley, on the Sierra Monica; of ligminuta, UCLA 1795, Santa Barbara County, Calif, Branch Canyon Sandstone, Miocene; of prior, UCLA 1745, Santa Barbara County, Calif, Branch Canyon Sandstone, Miocene; of andersoni, UC-D701, Fresno County, Calif, Santa Margarita Formation, Miocene. Supplementary description.—“Produced from beak to base, straight or slightly curved, substance very thick, coarsely laminated; upper valve flat, very thick, somewhat gibbous; lower valve profoundly ventricose, umbonated, the summit rising above beak 0f the opposite valve.” (Conrad, 1857b, p. 72) According to Takeo Suzuki (written commun., 1982), specimens of C. titan in the Topanga Formation vary considerably in outline. They are high, narrow, and thick valved in reef-type occurrence and thick val- ved but not so elongate as when they grow in an uncrowded environ- ment. The valves are usually unequal; one is flat or nearly flat and the TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE other thick and arched. Crassostrea titan has a broad, straight, some- what half-cylinder shaped resilifer with an accompanying resilifer trough. Striostrea? bourgeoisii bourgeoisii (Remond) has a narrow slightly curved resilifer in the early growth stage which changes abruptly into the broad, straight form. “The species varies considerably in abundance and morphology from north to south within the Castaic Formation. In the northern part of the formation, the species is more abundant and individuals are much larger than in the southern part. The average dimensions of specimens from north of San Francisquito Canyon are: length 30 cm., width 10 cm., and valve thickness 3 cm. The average dimensions of specimens from the southern part of the formation are: length 15 cm., width 8 cm., valve thickness 2 cm. Some valves from the southern part bear three to five irregular, round-crested ribs which may be discon- tinuous between laminae. Ribbing is more prevalent on left valves and particularly on those that are deeply cupped. Right valves are gener- ally flat without ribbing.” (Stanton, 1966, p. 26) “C. titan has been reported from middle and upper Miocene strata of central and southern California. Eaton, Grant, and Allen (1941) describe from Miocene strata of the Caliente Range [Cuyama Valley] a number of new species and a new subspecies of C. titan from material that would have been grouped previously under C. titan. In addition, three other varieties or subspecies of C. titan have been described. In the Castaic Formation, in strata that are contemporaneous, mor- phologic variability is so great that, according to the illustrations and descriptions of type specimens, several of the previously described species and subspecies could be identified among the Castaic spec- imens. Most shells found in the northern part of the formation corre- spond to typical C. titan; some thick specimens could be classified as the species C. ligminuta. The largest specimens from the southern part of the outcrop area of the Castaic Formation are eight to ten inches long and thus would correspond to C. titan var. prior, which differs from C. titan only in being about half the size, and in being presumably ancestral to it. Ribbed specimens differ from the species C. bourgeoisii, as described and illustrated by Clark (1915, p. 447, pl. 43) and by Eaton, Grant and Allen (1941, pl. 3, fig. 1) in lacking the elongate narrow ligamental pit. They differ from the species C. cier- boensis in having ribs that are narrow rather than broad and rounded. Ribbing, along with decrease in size and abundance, presumably reflects an environment to the southeast less hospitable for the species than to the northwest. The morphologic changes coincide with the change in environment from embayment in the north to open coast in the southeast.” (Stanton, 1966, p. 27) Comments—Stanton (1966, p. 27) and Takeo Suzuki (written com- mun., 1982) have called attention to the fact that C. titan shows marked variability in ribbing, maximum size, thickness, and shape and that this variability relates to the environment in which they grew. In addition, John G. Vedder (written commun., 1983) said that he had seen literally thousands of specimens of C. titan along the south side of Cuyama Valley and that no two specimens were alike. He added that the same is true for myriads of specimens in the San Juan- Estrella Creek area. Variability of Crassostrea is discussed under the generic heading above. The holotypes of Ostrea subjecta Conrad and Ostrea panzana Con- rad both have the same catalogue number, USNM 13338. They are both poorly preserved, have generalized locality data, and neither name has been used subsequently, to my knowledge. Woodring ( 1931, p. 386) said that the holotype of Ostrea panzana is free of matrix and probably represents a small specimen of Crassostrea titan Conrad. I see no reason for burdening the literature with these two specific names so I have synonymized them with C. titan. The holotype of 0. ligminuta is a worn, sponge-bored valve, 150 mm high, 170 mm long, and 170 mm thick. It has no distinctive shell chambers. Ostrea titan prior is distinguished from Ostrea titan only on the basis of size; it is the young of O. titan. C37 The holotype and paratype of Crassostrea titan andersoni Adegoke are worn, incomplete right valves. The holotype is poorly preserved and at least half of the original shell is missing. The paratype is not so poorly preserved as the holotype, but much of its shell is missing also. Adegoke (1969, p. 110) distinguished his subspecies from C. titan and other described subspecies on the basis of its relatively longer, nar- rower shell. The two right valves are not longer than right valves of C. titan: they only seem narrower because so much of the shell is missing. On the basis of the type material, C. titan andersoni is here syn- onymized with C. titan. Stenzel (1971, p. 127) placed titan in Crassostrea. Geographic range—Middle and southern California. Geologic range—Miocene. Occurrence in California—Miocene: Branch Canyon Sandstone (Vedder, 1973), Castaic Formation (Stanton, 1966), McLure Shale Member, Monterey Formation (Adegoke, 1969), Modelo Formation (Dehlinger and Jennings, 1952; Oakeshott, 1958), Neroly Sandstone (Eaton, Grant, and Allen, 1941; Weaver, 1949), Round Mountain Silt (Addicott, 1965), San Pablo Formation (Clark, 1915), Santa Margarita Formation (Fairbanks, 1904; Hill, Carlson, and Dibblee, 1958; Ade- goke, 1969; Squires and Fritsche, 1978; Addicott and others, 1978), Sobrante Sandstone (Weaver, 1953), and Topanga Formation (Arnold, 1907c; Vedder, written commun., 1978). Crassostrea columbiensis (Hanley) Plate 24, figure 2; plate 26, figure 2; plate 28, figures 1, 2, 4 Ostrea columbiensis Hanley, 1846, p. 187. Ostrea (Crassostrea) columbiensis Hanley. Olsson, 1961, p. 172, pl. 23, figs. 4, 4a. Ostrea corteziensis Hertlein, 1951b, p. 68-73, pl. 24, figs. 1, 2; pl. 25, fig. 7. Keen, 1971, p. 82, fig. 170. Ostrea chilensis Phillipi. Durham, 1950, p. 58, pl. 4, fig. 1; not Ostrea chilensis Phillipi, 1844. Crassostrea corteziensis (Hertlein). Bernard, 1983, p. 23. Ostrea iridescens Gray. G D. Hanna, 1926a, p. 468, pl. 26, figs. 4-7. Not Ostrea iridescens Gray, 1854. Ostrea californica Marcou. Hanna and Hertlein, 1927, p. 46. Grant and Gale, 1931, p. 149. Not Ostrea californica Marcou, 1858. Original description.-—“Ost. testa subinequivalvi, subtenui, lamellosa, albida, purpureo radiata, subcompressa; valvula inferiore magis convexa; superficie interna albida, submargaritacea; cardine denticulis nullis munito; cicatrice satis magna reniformi.” (columbien- sis) “Shell elongately ovate to subtrigonal in outline, moderately thick, beaks turned posteriorly; lower (left) valve moderately convex, upper valve flattish or gently convex; early portion of upper valve with 8—10 weak, scaly, radiating costae ending about 75 mm. from the beak, the remainder of the shell concentrically lamellose with faint traces of superficial radial sculpture, colored grayish-white to brownish-white, the brownish color more pronounced on juvenile shells; interior of lower valve with a large rather broad, ligamental area which is lightly transversely grooved, about 4 of these coarser than the others, the ligamental area is bordered on each side by a narrow groove; the anterior portion of the ligamental area centrally overhangs the body cavity; adductor muscle impression posteriorly situated, broadly semi-crescentic above, white with traces of purplish-brown concentric bands or lines; the remainder of the interior white with occasional traces of purplish-brown. Upper (right) valve usually flat or nearly so, exteriorly it is similar to the lower valve in coloration but it lacks the indistinct radiating furrows; interiorly the anterior portion of the ligamental area is raised centrally; adductor impression a little larger than that of the lower valve and truncated above by white shell mate- C38 rial. Holotype: height, 153 mm.; width (maximum), 98 mm.; convexity (both valves together), approximately 56 mm.” (corteziensis) Holotype.—In Museum Cuming; of corteziensis CAS 4288. Ripe locality—St. Elena, west Columbia; of corteziensis CAS 28186. Bahia Kino, Golfo de California, Sonora Mexico. Holocene. Supplementary description.—“Elongate, somewhat triangular, with a wide ligamentary area, rather flat. The surface shows faint radial furrows. *** This species *** was long known as O. chilensis Philippi, 1844, a mis-identification; for Chilean specimens show a rounded shape and denticles along the hinge margin.” (Keen, 1971, p. 82) “All the specimens I have seen are attached by the entire surface of the lower valve. The shape varies from oblong to suborbicular, and the valves are of equal length, but the shelly substance of the shallow upper valve fits into the lower one, and is only continued to the margin by the lamellae, which, when the habitat permits, branch into wavy foliations.” (Hanley, 1846, p. 187) “This species [0. corteziensis] has generally been referred by various authors to Ostrea chilensis Philippi. That species was originally described from Chile. * ** 9 to 10 denticles or traces of such, are present on specimens of O. chilensis from Calbuco, Chile. *** No trace of such denticles has been observed on any of the specimens studied from the Gulf of California. The base of the hinge of the upper valve of the Chilean shells does not possess such a large transverse ridge.” (Hertlein, 1951b, p. 68—69) “Shell relatively small (length to about 90 mm.), very irregular, the attached valve deep, cup-shaped, the upper valve smaller and gener- ally flattened. Sculpture smooth or with crudely formed ribs.” (Olsson, 1961,p. 172.) Comments.—Harold W. Harry (written commun., 1983) called my attention to the fact that O. corteziensis is a junior synonym of 0. columbiensis. Geographic range—Living: Golfo de California to Ecuador; fossil: southern California to Baja California Sur. Geologic range.—Miocene(?); Pliocene to Holocene. Occurrence in the Californias.—Miocene or Pliocene: Imperial For- mation (Stump, 1979); Pliocene: Gloria (Stump, 1979) and San Marcos (Durham, 1950) Formations. Habitat—Generally attached to roots of mangroves; adhering to rocks at low tide. Genus CRASSOSTREA? Crassostrea? vaquerosensis (Loel and Corey) Plate 2], figure 2; plate 25, figure 2 Ostrea vaquerosensis Loel and Corey, 1932, p. 192, pl. 19, figs. 1a, 1b. Addicott, 1965, p. 0104, fig. 3g. Original description—“Shell large and heavy, nearly round or slightly higher than long, nearly equivalve, upper valve more convex than lower; beaks rounded and slightly curved, exterior of shell with- out ornamentation other than concentric, fairly prominent growth ridges; muscle scar round, located posteriorly. Height, 190 mm.; width 170 mm.; diameter (through both valves), 90 mm.” Holotype.—CAS/SU 617; missing and presumed lost; paratypes CAS 6789, 6790. Type locality—Jeff Harris Ranch, west of Pleyto [T 24 S., R. 9 E. I, Bryson Quad, Monterey County, Calif. Vaqueros Formation, Oligocene and Miocene. Comparison—“This species is distinct from O. titan in its constant roundness and equality of valves.” (Loel and Corey, 1932, p. 192) Geographic range—Middle and southern California. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Geologic range—Oligocene and Miocene. Eaton and others (1941, p. 199) said that C. vaquerosensis is restricted to the uppermost Vaqueros and aids in zoning the Vaqueros substage. Comments.—The generic assignment is uncertain and C.? vaquerosensis may be a variant of C. titan. Occurrence in California—Oligocene and Miocene: Mindego Basalt (Cummings and others, 1962); Miocene: J ewett Sand (Addicott, 1965), Painted Rock Sandstone Member, Vaqueros Formation (Loel and Corey, 1932), Pyramid Hill Sand Member, Jewett Sand (Park and others, 1963). Crassostrea? englekyi (Hertlein) Plate 20, figure 1; plate 22, figure 1 Ostrea englekyi Hertlein, 1928, p. 143-144, pl. 25, fig. 1. Loel and Corey, 1932, p. 190, pl. 15, fig. 3. Bereskin and Edwards, 1969, p. 77, pl. 32, figs. 421, 4b. Original description—“Shell elongate triangular. Lower valve thick, made up of flattish layers of shell material, thickest in middle part of valve; sides of valve fairly straight. Left valve thinner but otherwise similar to right valve. Altitude 143.4 mm.; width of ventral margin of shell 86 mm.” Holotype.—CAS 4116. Type locality—CA8 1156. Santa Barbara County, Calif. Temblor [upper part of Vaqueros] Formation of Loel and Corey, 1932; San Onofre Breccia of Bereskin and Edwards, 1969, Miocene. Comparison—“The hinge of Ostrea englekyi isnot fully exposed but it apparently belongs to the Ostrea virginica Gmelin group. It differs from that species in its extremely triangular shape, straight sides and thick shell. From 0. freudenbergi Hertlein and Jordan, 0. englekyi differs in its larger size, greater thickness and straight sides and different hinge. The present species is apparently not close to O. chilensis Philippi in the early part of shell nor in general shape. 0. englekyi most closely resembles a species of recent Ostrea which is found in the Gulf of California apparently differing only in minor details. The triangular shape, narrower ligament pit and wider ante- rior margin distinguish O. englekyi from O. californica Marcou, a species once reported by Hanna [1926a, p. 468] as O. iridescens Gray but later [M. A. Hanna and Hertlein, 1927, p. 45-47] recognized as distinct from Gray’s recent species.” (Hertlein, 1928, p. 143-144) Comments—The holotype of C.? englekyi is a double-valved spec- imen with the valves together and closed. The specimen is worn and was originally somewhat wider at the umbonal end and thus not “extremely triangular” as stated by Hertlein (1928, p. 143). The straight steep sides of the left valve are distinctive and may not simply relate to where it grew. The edges of the shell layers on the left valve may have been fluted. The right valve is smooth and flat to concave. On the basis of the holotype, the generic assignment is uncertain. Geographic range—Southern California. Geologic range.—Oligocene(?); Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros For- mation (Bereskin and Edwards, 1969); Miocene: Temblor Formation (Hertlein, 1928) and upper part of Vaqueros Formation (Loel and Corey, 1932). Crassostrea? ashleyi (Hertlein) Plate 19, figures 3, 5; plate 20, figures 2-6; plate 21, fig. 3; plate 22, fig. 2; plate 24, fig. 5. Ostrea ashleyi Hertlein, 1934b, p. 1, 3, pl. 1, figs. 2, 3; pl. 2, fig. 1. Adegoke, 1969, p. 107—108, pl. 4, fig. 5. Addicott, 1965, p. 0106, fig. 4q. TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE Ostrea altatemblorensis Grant and Eaton in Eaton, Grant, and Allen, 1941, pl. 2, fig. 2 [described in plate explanation]. Ostrea arnoldi Adegoke, 1969, p. 106-107, pl. 4, figs. 1, 2, 6, 9; pl. 5, fig. 5. Ostrea hertleini Adegoke, 1969, p. 108, pl. 4, figs. 3, 4; pl. 5, fig. 4; pl. 6, fig. 9. Original description—“Lower valve narrowly oblong, wider at base; exteriorly ornamented by numerous fluted ribs; area of attach- ment near beak unomamented. Interior of margin not folded; muscle scar fairly large; ligament groove long and fairly wide. Upper valve long and narrow; on the interior beneath the beak a long narrow elevated area is present which fits into the groove of the lower valve. Height of shell (beak to base, incomplete); 216 mm.; width of shell (at base) 108 mm.” (ashleyi) “Lower (left) valve. Average length about 6 inches; Width commonly from a third to a half of this. Lower valve moderately thick, with 5-8 characteristically narrow, somewhat angular, rather evenly spaced, in many specimens almost knife-edge, radial ribs separated by rounded trough-like interspaces which may bear minor riblets. Upper (right) valve thinner, flattish, with irregular, concentric growth rugosities, but without definite continuous radial sculpture. Ligamental pit of lower valve concave, elongate, tapering, and ordinarily curved. Differs from O. wiedeyi of the older Miocene in its fewer, narrower plications, and the wide, rounded troughs between these. Differs from the Pliocene species 0. vespertina in all of the foregoing attributes, and in its more elongate shape, larger size, and thicker valves.” (altatemblorensis) “Shell medium sized, oval to subcircular, not constricted at hinge area, valves moderately thick, composed of several thin flat laminae; outer surface rather smooth, often faintly corrugated or with rather indistinct ornamentation; ligamental groove ralatively short, often less than one-sixth length of shell, rather broad, with broad raised margins; interior of shell evenly concave, except in area immediately adjacent to ligamental groove where it is deep; muscle scar large, impressed, with a semicircular outline, ventral margin broadly rounded, anterior margin almost straight; muscle scar located on anterior edge of shell about a third of length from the ventral margin, displaced toward ‘dorsal’ margin; both valves equally inflated.” (arnoldi) “Shell long, narrow, only slight change in diameter from anterior to posterior end; left valve heavy, thick, convexly arched; right valve thin, flat anteriorly, concave posteriorly; growth lines more distinct on right than on left valve; ligamental groove short, narrow, bounded by rela- tively wide, flat margins; ligamental groove narrow but fairly deep, deeper on left valve; adductor muscle scar not very distinct, subcir- cular in outline, centrally placed, about midway in valve; shell straight to slightly curved, ventral margin gently rounded, anterior margin bluntly acute; dorsal margin almost straight.” (hertleini) Holotype.—CAS 6065; of altatemblorensis UCLA 8970; of arnoldi UCMP 36646; of hertleini UCMP 36654. Type locality—CA8 933. Kern County, Calif. Temblor Formation, Oligocene and Miocene; of altatemblorensis UCLA 512, San Luis Obispo County, Calif. Branch Canyon Sandstone, Miocene; of arnoldi UC D-1075. Fresno County, Calif. Temblor Formation, Oligocene and Miocene; of hertleini UC D-1057. Kings County, Calif. Temblor Forma- tion, Oligocene and Miocene. Comparison—“This long narrow oyster with pronounced ribs orna- menting the lower valve, which bears a long ligament groove, inter- nally, is quite distinct from any other species from western North America. These features of the lower valve as well as the long narrow upper valve with the internally raised area below the beak, easily distinguish the species from other lower Miocene forms such as O. loeli Hertlein, O. wiedeyi Hertlein, and 0. howelli Wiedey.” (Hertlein, 1934b, p. 1-2) C39 “Ostrea ashleyi Hertlein is characterized by an elongate, narrow ligamental groove, similar to that of 0. bourgeoisii to which it has been referred by several workers. It differs from 0. bourgeoisii by its much smaller size, thin valves, and relatively large semicircular muscle scar. It was described from the Temblor of Kern County. The species occurs abundantly in an 8-foot oyster bed in the middle of the Temblor Formation of the Coalinga region.” (Adegoke, 1969, p. 108) Comments.—The holotype of C. .9 ashleyi is a fairly large, somewhat worn left valve. The exterior is sculpted by irregular ribs that are somewhat fluted. The muscle impression is semiovate and the liga- mental area is large. The deep resilifer is bordered anteriorly by a prominent bourrelet (area flanking resilifer) and posteriorly by a bourrelet projecting upwards at an angle of about 45°. The body cavity is shallow. The left valve holotype of O. altatemblorensis has narrow, sharp- edged plicae or folds that are irregularly nodose and separated by shallow, U-shaped interspaces. The right valve holotype of Ostrea arnoldi is small and the exterior very worn. Some of the exposed shell layers show traces of fine, radial ribs, suggesting Striostrea. The left valve paratype of 0. arnoldi is small and badly worn; it does not have traces of radial ribs as are present on C.? ashleyi. The holotype of Ostrea hertleini is a double-valved specimen with the valves together and closed. It is small and relatively narrow. The left valve, although very worn with the outer shell layers missing, seems to have had fluted ribs. The left valve is smooth, worn, and flat to concave. Geographic range—Middle and southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Temblor For- mation; Miocene: Branch Canyon Sandstone (Hill and others, 1958; Vedder, 1973; Adegoke, 1969) and Olcese Sand (Addicott, 1965). Crassostrea? eucorrugata (Hertlein) Plate 25, figures 3-5; plate 26, figure 1; plate 27, figure 1 Ostrea titan corrugata Nomland, 1917, p. 306, pl. 16, fig. 1; pl. 17, fig. 1. Not Ostrea corrugata Brocchi, 1814; not Ostrea corrugata Hutton, 1873. Ostrea titan eucorrugata Hertlein, 1934b, p. 5, new name. Ostrea titan Conrad eucorrugata Hertlein. Adegoke, 1969, p. 109. Ostrea cierboensis Grant and Eaton in Eaton, Grant, and Allen, 1941, pl. 3, fig. 2. Original description—“Shell large, very heavy, when full grown sub-ovate but in earlier stages of very irregular outline. Surface sculp- tured by well marked growth lines which at the edges are irregularly folded into prominent radiating ridges Ligamental groove wide, tri- angular, extending nearly across anterior end of shell. Muscular impression large, rectangular, almost invisible in type. Dimensions of lower valve: length 235 mm.; width, 150 mm.; height, 120 mm.” (cor- rugata) “View showing lower (left) valve, Averages 5-6 inches in length and about 4 in width. Differs from all other known large upper Miocene oysters of California in being nearly as wide as long, and in having broad, somewhat regular radial plications on the lower valve. Upper (right) valve thin and flattish. Moderately thin-shelled, large-cavitied with a broad, very short, flattish ligamental pit commonly about 1 inch wide and 1/2 inch long. Well preserved specimens normally occur as matched valves. Has probably previously been erroneously identified as the smaller and younger species 0. vespertina (Pliocene). Differs from the latter species in its larger size, thicker shell and fewer, broader plications.” (cierboensis) C40 Holotype.—UCMP 11309; of cierboensis UCLA 8980. Type locality.——UC 2284. Fresno County, Calif. Santa Margarita Formation, Miocene; of cierboensis UCLA 1751, Santa Barbara County, Calif, Cierbo Formation [Branch Canyon Sandstone], Miocene. Comparison.—“Distinguishable from the typical Ostrea titan Con— rad which is also found in the Santa Margarita Formation by the prominent folds on surface and the greater convexity of lower valve.” (Nomland, 1917, p. 306) Comments.-—The growth lamellae are fluted at their edges, thick at their base but almost paper thin at their free margin, and where broken across are seen to be built of thick, prismatic calcite crystals. On the basis of the growth lamellae (Stenzel, 1949, p. 35-36), the holotype specimen was at least 8 years old. Almost the entire exterior and interior surfaces of the left-valve holotype show pseudovesicular structure. Stenzel (1971, p. N987) illustrated true honey-comb ves- icular structure and used this character to identify the Pycnodon— teinae. Cross sections of the prismatic shell layer produced at shell breaks show only the vertical prismatic crystals and no internal ves- icular layers. Thus the pseudovesicular structure, which is believed to be a solution artifact, consists of small pits conforming to the size of the sand grains, some of which are still attached. The pits were caused by leaching of the shell. Shell characters of C.? eucorrugata that make assignment of the species to Crassostrea dubious are: the ligamental area of the left valve is longer than high and the left valve has thick, prismatic shell layers. These two characters suggest Fleminostrea, but C.? encor- rugata has a beaked left valve umbo, the left valve is highly convex, and the valves are not nearly equal in size. No vesicular shell structure was seen, but C. .9 eucorrugata may belong in the subfamily Pycnodon- teinae. Geographic range—Middle and southern California. Geologic range—Miocene. Occurrence in California—Miocene: Branch Canyon Sandstone (Eaton, Grant, and Allen, 1941; Vedder,1970) and Santa Margarita Formation (Nomland, 1917; Wilson, 1944; Addicott and Vedder, 1963). Crassostrea? californica osunai (Hertlein) Plate 27, figure 2 Ostrea californica osunai Hertlein, 1966, p. 272-273, figs. 2-6, 8, 9. Original description—“Shell, a left valve, elongated, longer than wide, thick with uneven, wavy growth laminae; exterior flattish, lack» ing ornamentation; interior with a shallow body cavity; ligamental pit rather wide, concave, elongate, the laminae of growth form a nearly straight line across the pit; muscle impression on the type specimen indistinct, apparently at about one third the length of the shell from the ventral margin. Dimensions: Length (apex lacking), 393 mm., maximum width, 140 mm., maximum thickness, 84 mm. “Right valve, a paratype, ventral portion lacking; a raised, convex ridge corresponds to the ligamental pit of the opposite valve. Dimen- sions; length (ventral portion lacking), 238 mm., maximum width, 133 mm., maximum thickness, 53 mm.” Holotype.—CAS 12823. Type locality—CA8 38855. From the southwest end of Punta Con- cepcion, Baja California Sur. Salada Formation, Pliocene. Comparison—The dorsal half of two specimens of C. californica osunai, about 130 mm long, closely resemble specimens of C. califor— nica s. s., differing only in the larger and thicker shell. One lower valve is recessed under the hinge, but other valves are not. Similar vari- ability can be observed among specimens of C. californica s. 3.. None of the valves of C. californica s. s. are as large and thick as those of C. californica osunai nor is the ligamental pit and corresponding liga- mental ridge on the opposite valve as large as those on valves of C. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA californica osunai. Some of the large valves of C. californica osunai resemble Crassostrea bourgeoisii Remand, as illustrated by Clark (1915, pl. 43), but differ from that species in their much more elongate, narrower outline, and broader ligamental pit. (Hertlein, 1966, p. 273) Comments—The holotype is a double-valved specimen with the valves separated. The early portion (one-fourth) of the left valve is ribbed; the right valve is smooth. Geographic range.—Baja California Sur. Geologic range—Pliocene. Occurrence in Baja California—Pliocene: Salada Formation (Hertlein, 1966). FOSSIL LOCALITIES [Corrections and information not in the original description are in brackets; feet and miles are convened to the metrit‘ system: formations are riled as emendcrl by later workers. where penincnl| California Academy of Sciences: CAS 933. Center of sec. 32, T. 28 S., R. 29 E., Kern County, Calif. Temblor Formation. CAS 945. Southeast of Bahia Tortola, Baja California Sur. Alme- jas Formation. CAS 1150. West of Arlington Canyon, Santa Rosa Island, Santa Barbara County, Calif. Vaqueros Formation. CAS 1154. Oyster bed near spring on ridge to south of San Augustine Canyon, about 1.6 to 2 km from mouth of canyon, Santa Rosa Island, Calif. Temblor Formation. CAS 1156. About 0.4 km southeast of spring on ridge south San Augustine Canyon, east of dike near top of hill, Santa Rosa Island, Calif. Temblor Formation Miocene. CAS 1163. East of Crook Point, San Miguel Island, Santa Barbara County, Calif. Vaqueros Formation. CAS 5955. San Diego, Calif. Holocene. Los Angeles Natural History Museum: LAM 305. 730 m east and 310 in south ofNW cor. sec. 8, T. 19 S., R. 2 W., San Ysidro Quad. (1943 edition), [San Diego County], Calif. San Diego Formation. Stanford University [All these collections are now in the California Academy of Sciences]: SU 59. Turritella bed above San Gregorio Lagoon, 190 km north of Magdalena Bay, on the trail from Arroyo Mesquital to La Purisima, Baja California Sur. Isidr0(?) Formation. SU 446. Near Sespe Creek, 8.8 km northeast of Wheeler’s Hot Springs, [sec. 32, T. 6 N., R. 22 W], Mt. Pinos Quad, Ventura County, Calif. Temblor Formation. SU 449. Val Celico, a little west of Pleyto, Monterey County, Calif. Vaqueros Formation. University of California at Berkeley: UC 790. East of Lower Lake Village 12 km, 365 m south of Nerndon Creek bridge, SE1/4, NEl/i, sec. 11, T. 12 N., R. 7 W., Lake County, Calif. Martinez Formation. UC 1131. Southwest of town of Walnut Creek 0.8 km, in creek bed, Long. 122°4’8”, Lat. 37°53’7” [Concord Quad], Contra Costa County, Calif. San Ramon Formation. UC 1540. South of Stewartville 1.6 km, NE cor. NW1/4 sec. 15, T. 1 N., R. 1 E., Mt. Diablo Quad, Contra Costa County, Calif. Martinez Formation. UC 2284. Near middle of south boundary 0fNE1/4, sec. 10, T. 19 S., R. 15 E., Fresno County, Calif. Santa Margarita Formation, Miocene. UC 3752. Simi Valley, Santa Susana Quad, SE 1/4, SEl/t, sec. 7, T. 2 N., R. 17 W., Ventura County, Calif. Martinez Formation. TERTIARY MARINE PELECYPODS: PLICATULIDAE AND OSTREIDAE C41 UC 3981. At 15 In above high tide level in small gully 0.4 m south of Soledad Valley, La Jolla Quad, San Diego County, Calif. La Jolla Group. UC 5062. In sea cliff south of mouth of Soledad Valley, due west of midpoint between “P” and “u” of “Pueblo”, La Jolla Quad, San Diego County, Calif. La Jolla Group, Eocene. UC A-321. About 0.5 In due south of end of Santa Ynez River bridge, south of Santa Ynez Mission, on east side of Alisal Creek [Lompoc Quad, Santa Barbara County], Calif Vaqueros Formation. UC A-326. Upper end of San Antonio Creek Canyon, northwest of mouth of Lion Canyon, on west side, Ventura Quad, Ven- tura County, Calif. Vaqueros Formation. UC A—336. On long sharp northwest spur of Oak Ridge 1.6 km east of Grimes Canyon [NW1/4 sec. 8, T. 3 N., R. 19 W., Piru Quad, Ventura County], Calif. Vaqueros Formation. UC D-701. From 2 + In thick, prominent oyster and pecten “reef ’, the most prominent ledge-forming Ostrea-Pecten “reef” on the slope of the hills a few feet northwest of Shell Oil well 254-15. 2,460 feet north, 2,530 feet west, sec. 15, T. 19 S., R. 15 E., Domengine Ranch Quad, Fresno County, Calif. Santa Margarita Formation. UC D-1057. 190 In north, 395 In west, sec. 3, T. 23 S., R. 16 E., Reef Ridge Quad, Kings County, Calif. Temblor Formation. From two prominent oyster beds about 3.5 In apart and from coarse sandstone bed below the lower oyster bed. Lateral extent of collection about 30 m. UC D-1075. Sec. 21, T. 19 S., R. 15 E., 745 m north and 215 111 east, Domengine Ranch Quad, Fresno County, Calif. From approximately 2.5 m oyster bed in light gray and buff colored, fragile, silty shale. Fossil bed crops out for consid- erable distance along road on the west slope of the hills. Temblor Formation. U.S. Geological Survey, Menlo Park, Calif: USGS 3220. 328 In north and 91 In west ofSE cor. sec. 4, T. 7 S., R. 8 W., San Juan Capistrano Quad. (1949 edition), altitude about 80 In. On east bank of Aliso Creek, base of Monterey Shale. Lat. 33° 35.3’ N, long., 117° 47.7’ W, Calif. Monterey Shale. USGS 3426. Third Street Tunnel, Los Angeles, Los Angeles County, Calif. Repetto Formation. USGS 4715. South end ofKettleman Hills in sec. 10, T. 25 S., R. 19 E. [Lost Hills Quad, Kern County], Calif. Etchegoin For- mation. University of California at Los Angeles: UCLA 512. Ridge between main and east Abbott Canyons, oyster bed 6 + In thick and 6 m conglomerate below. (Not found in bottom of canyon). [SW1/4 sec. 11, T. 11 N., R. 27 W., McKit- trick Quad, northeast slope of] Caliente Range, San Luis Obispo County, Calif. Upper Temblor Formation [Branch Canyon Sandstone]. UCLA 1745. Cuyama Valley, Branch Canyon, east of head of Dis- covery Gulch. On top of knoll, Zone 9, Santa Barbara County, Calif. Middle Cierbo Formation [Branch Canyon Sandstone]. UCLA 1751. About 350 In S 25° E from Branch Canyon along ridge west side Discovery Gulch. 18-22 m down the 16° slope from prominent white sandstone reef which forms the strike ridge N 25° W, along the weathered surface exposure of Ostrea cierboensis and Astrodapsis gregerseni. Oysters very abundant at southwest end of exposure above head of Discovery Gulch westward. South side Branch Canyon, Cuyama Valley, Santa Ynez Quad, Santa Barbara County, Calif. Cierbo Formation [Branch Canyon Sandstone]. UCLA 1795. Short Canyon branch of Bitter Creek. Reef at base of the Astrodapsis section exposed therein. Collected on west side of Short Canyon, from Ostrea reef interbedded with A. cf. tumidus. About 70 In below upper shale of this locality. [South side Cuyama Valley, Santa Ynez Quad, Santa Bar- bara County, Calif] Cierbo Formation [Branch Canyon Sandstone]. University of California at Riverside: UCR 6899. Light gray concretions with abundant oyster debris 134 In due east of small hill 1461 m NW 11° from hill 496 and 748 m southwest 5° of hill 1331. 928 m above base of Simi Conglomerate, Calabasas Quad, California. University of Oregon: U0 130. Near Glide, Douglas County, Oregon. Umpqua Forma- tion. University of Washington: UW 160. Bluff at Porter Station in Northern Pacific Railroad cut, sec. 22, T. 17 N., R. 4 W., Grays Harbor County, Wash. Lincoln Creek Formation. GEOLOGIC FORMATIONS CITED FOR OCCURRENCE OF PELECYPODS. Family Plicatulidae to Family Ostreidue Capistrano Formation Careaga Sandstone Name Age California: Alegria Formation1 Oligocene Anchor Silt1 Pleistocene Avenal Sandstone Eocene Bay Point Formation Pleistocene Beechers Bay Member, Monterey Formation1 Miocene Branch Canyon Sandstone Miocene Briones Sandstone, San Pablo Group Miocene Canada Formationl Eocene Miocene and Pliocene Pliocene Carlotta Formation Pleistocene Castaic Formation1 Miocene Cebada Member, Careaga Sand or Sandstone Pliocene Cierbo Sandstone, San Pablo Group Miocene Goldwater Sandstone and Goldwater Sandstone Memberl, Tejon Formation Eocene Cozy Dell Shale and Cozy Dell Shale Memberl, Tejon Formation Eocene Delmar Formation, La Jolla Group Eocene Domengine Formation or Sandstone Eocene Etchegoin Formation Fernando Formation Foxen Mudstone Miocene and Pliocene Pliocene and Pleistocene Pliocene ‘Stratigraphic nomenclature used is that of the references cited in the text and does not necessarily accord with that of the U.S. Geological Survey. C42 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Gaviota Formation1 Imperial Formation Jewett Sand Juncal Formation La Jolla Group Lomita Marl Member, San Pedro Formation Martinez Formation Matilija Sandstone Medill Sand1 Merced Formation Mindego Basalt Modelo Formation Monterey Formation, Shale, or Group Neroly Sandstone, San Pablo Group Niguel Formation Olcese Sand Painted Rock Sandstone Member, Vaqueros Formation Palos Verdes Sand Pancho Rico Formation Paso Robles Formation Pico Formation Potato Harbor Formation1 Purisima Formation Pyramid Hill Sand Member, Jewett Sand Quail Canyon Sandstone Member, Vaqueros Formation Rincon Shale Rose Canyon Shale1 Round Mountain Silt Sacate Formation1 Saltos Shale Member, Monterey Formation San Diego Formation San Joaquin Formation San Pablo Formation San Pedro Formation or Sand San Ramon Sandstone Santa Margarita Formation Santa Susana Formation1 Santos Shale Member, Temblor Formation Saug'us Formation Simi Conglomerate Sisquoc Formation Sobrante Sandstone Soda Lake Sandstone Member, Vaqueros Formation Tejon Formation Temblor Formation Eocene and Oligocene Miocene or Pliocene Miocene Eocene Eocene Pliocene Paleocene Eocene Pleistocene Pliocene and Pleistocene Oligocene and Miocene Miocene Miocene Miocene Pliocene Miocene Miocene Pleistocene Miocene Miocene, Pliocene, and Pleistocene Pliocene and Pleistocene Pliocene Miocene and Pliocene Miocene Oligocene and Miocene Oligocene and Miocene Eocene Miocene Eocene Miocene Pliocene Pliocene Miocene Pliocene and Pleistocene Miocene(?) Miocene Paleocene and Eocene Oligocene and Miocene Pliocene and Pleistocene Paleocene Miocene and Pliocene Miocene Oligocene and Miocene Eocene Oligocene and Miocene Timms Point Silt Member, San Pedro Formation Pleistocene Tomales Formation Pleistocene Topanga Formation Miocene Miocene and Pliocene Oligocene and Towsley Formation Vaqueros Formation Miocene Wygal Sandstone Member, Temblor Formation Oligocene Baja California peninsula: Almejas Formation Pliocene Boleo Formation Pliocene Cantil Costero Formation Pliocene Carmen Formation Pliocene Comondu Formation Miocene Gloria Formation Pliocene Infierno Formation Pliocene Isidro Formation Miocene Marquer Formation Pliocene Salada Formation Pliocene San Marcos Formation Pliocene San Ignacio Formation Pliocene Santa Rosalia Formation Pleistocene Sepultura Formation Paleocene Tortugas Formation Miocene Washington: Cowlitz Formation Eocene Oregon Umpqua Formation Eocene Dominican Republic: Emperador Member, La Boca Formation Miocene Gurabo Formation Miocene REFERENCES CITED Addicott, W. 0., 1965, Miocene macrofossils of the southeastern San Joaquin Valley, California: US. Geological Survey Professional Paper 525-0, p. C101-C109, 4 figs. 1972, Provincial middle and late Tertiary molluscan stages, Temblor Range, California, in Pacific Coast Miocene Bio- stratigraphic Symposium: Society of Economic Paleontologists and Mineralogists, Pacific Section, Bakersfield, California, 1972, Proceedings, 26 p., 4 pls., 3 figs, 5 tables, 1973, Oligocene molluscan biostratigraphy and paleontology of the lower part of the type Temblor Formation, California: US. Geological Survey Professional Paper 791, 48 p., 9 pls., 5 figs, 1 table. Addicott, W. 0., and Galehouse, J. S., 1973, Pliocene marine fossils in the Paso Robles Formation, California: US. Geological Survey Journal of Research, v. 1, no. 5, p. 509-514, 4 figs. Addicott, W. 0., Poore, R. Z., Barron, J. A., Gower, H. 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McLean, James, 1978, Marine shells of southern California: Los Angeles County Museum of Natural History, Science Series 24, (rev. ed.), 104 p., 54 figs. Mina, Federico, 1956, Geologia de la parte sur de la Peninsula de Baja California: International Geological Congress, 20th, Mexico City, Mexico, 1956, Excursion A—7, 79 p., 5 maps, 1 table. 1957, Bosquejo geologico del Territorio Sur de la Baja Califor- nia: Asociacion Mexicana Geologos Petroleros Boletin, v. 9, p. 139-269, Minch, J. C., Gastil, Gordon, Fink, William, Robinson, John, and James, A. H., 1976, Geology of the Vizcaino Peninsula, in Howell, D. G., ed., Aspects of the geologic history of the California conti- nental borderland: American Association of Petroleum Geologists, Pacific Section, Misc. Pub. 24, p. 136-195, 5 text figs. Moore, E. J, 1977, A uniquely sculptured middle Miocene pelecypod of the genus Lima: The Veliger, v. 19, n0. 3, p. 277-278, 10 figs. Moore, R. C., 1969, Treatise on invertebrate paleontology: Geo- logical Society of America and University of Kansas, pt. N, Mol- lusca, v. 1-3, 1224 p., illus. Nelson, R. N., 1925, A contribution to the paleontology of the Mar— tinez Eocene of California: University of California, Department ofGeological Sciences Bulletin, v. 15, no. 11, p. 397-466, pls. 49-61. Nomland, J. 0., 1917, Fauna ofthe Santa Margarita beds in the north Coalinga region of California: University of California, Depart» ment of Geology Bulletin, V. 10, no. 18, p. 293—326, pls. 14-20. Oakeshott, G. B., 1958, Geology and mineral deposits of San Fer- nando quadrangle, Los Angeles County, California: California Division of Mines Bulletin 172, 147 p. Ogle, B. A. 1953, Geology of the Eel River Valley area, Humboldt County, California: California Division of Mines Bulletin, v. 164, 128 p. Oldroyd, I. S., 1924 [1925], The marine shells of the West Coast of PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA North America: Stanford University Publications, Geological Sci< ences, v. 1, no. 1, 247 p., 57 pls. Olsson, A. A., 1961, Mollusks of the tropical eastern Pacific: Ithaca, New York, Paleontological Research Institute, 547 p., 86 pls. 1964, Neogene mollusks from northwestern Ecuador: Ithaca, New York, Paleontological Research Institute, 256 p., 38 pls. Orbigny, Alcide (1’, 183447, Voyage dans l’Amerique Meridionale, V Mollusques: Paris, v. 5, pt. 3, 758 p.; atlas 85 pls. Oyama, Katura, 1952, Preliminary notes on the ostreid phylogeny: Annotationes Zoologicae Japonenses, v. 25, nos. 1-2, p. 337-342, University of Tokyo, Zoological Institute, Zoological Society of Japan. Packard, E. L., 1923, An aberrant oyster from the Oregon Eocene: University of Oregon Publication, v. 2, no. 4, 6 p., 4 pls. Palmer, K. V. W., 1938, Neocene Spondyli from the southern United States and tropical America: Paleontographica Americana, v. 2, no. 8, p. 147-162, 3 pls. 1958, Type specimens of marine Mollusca described by P. P. Carpenter from the West Coast: Geological Society of America Memoir 76, 376 p., 35 pls., 2 tables. Park, W H., Weddle, J. R., and Barnes, J. A., 1963 [1964], Main, Coffee Canyon, and Pyramid areas of Round Mountain oil field [California]: California Oil Fields, v. 49, no. 2, p. 23-37. Pleshakov, I. B., 1939, Tertiary deposits ofthe Utkholoksk Region of west Kamchatka: Nentianoi Geologo Razvedochny Institut Trudy, series A, issue 123. Poli, J. X., 1795, Testacea utriusque Siciliae eorumque historia et anatome: Parma, Folio, v. 2, 344 p., pls. 19-39. Purchon, R. D., 1977, The biology of the Mollusca: v. 57 of Interna- tional Series of monographs in pure and applied biology; Zoology, New York, Pergamon Press, 560 p., 185 figs, 21 tables. Remond, Auguste, 1863, Description of two new species of bivalve shells from the Tertiaries of Contra Costa County: California Academy of Sciences Proceedings, v. 3, p. 13. Rochebrune, A.< 0.8). GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-C PLATE 22 C RASSOS TREA .7, STRIOS TREA ? PLATE 23 FIGURES 1-7. Crassostrea titan (Conrad) (p. 35). 1. Hypotype ofArnold (1907a, pl. 45, fig. 2) USNM 164987. Topanga Formation, California, Miocene. 2, 6. Hypotype of Clark (1915, pl. 44, fig. 1) UCMP 15565. San Pablo Formation, California, Miocene. 3, 7. Holotype of Ostrea panzana Conrad USNM 13338. Santa Margarita(?) Formation, California, Miocene. 4, 5. Holotype of Ostrea subjecta Conrad USNM 13338. Santa Margarita(?) Formation, California, Miocene. PROFESSIONAL PAPER 1228-C PLATE 23 GEOLOGICAL SURVEY CRASSOS TREA PLATE 24 FIGURES 1, 3, 4, 6. Crassostrea titan (Conrad) (p. 35). 1, 6. Paratype of Ostrea titan andersoni Adegoke UCMP 36662 ( X 0.5). Santa Margarita Formation, California, Miocene. 3, 4. Holotype of Ostrea titan andersoni Adegoke UCMP 36661 (X 0.5). Santa Margarita Formation, California, Miocene. 2. Crassostrea columbiensis (Hanley) (p. 37). Hypotype of Ostrea chilensis Phillipi of Durham (1950, pl. 4, fig. 1) UCMP 15505. Unnamed Pliocene strata, Isla Carmen, Baja California Sur. 5. Crassostrea? ashleyi (Hertlein) (p. 38). Holotype of Ostrea altatemblorensis Grant and Eaton UCLA 8970, Branch Canyon Sandstone/Caliente Formation, California, Miocene. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-C PLATE 24 CRASSOS TREA, CRASSOS TREA .7 PLATE 25 FIGURES 1. Striostrea? bourgeoisii bourgeoisii (Rémond) (p. 34). Hypotype of Clark (1915, pl. 43) UCMP 11566 ( X 0.5). San Pablo Formation, California, Miocene. 2. Crassostrea? vaquerosensis (Loel and Corey) (p. 38). Paratype CAS 6789 ( X 0.8). Vaqueros Formation, California, Oligocene and Miocene. 3-5. Crassostrea‘? eucorrugata (Hertlein) (p. 39). 3. Holotype of Ostrea cierboensis Grant and Eaton, UCLA, 8980 ( X 0.8). Cierbo Formation, California, Miocene. 4, 5. Holotype UCMP 11309 ( X 0.4). Santa Margarita Formation, California, Miocene. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-C PLATE 25 S TRIOS TREA .7, CRASSOS TREA .7 FIGURES 1. PLATE 26 Crassostrea? eucorrugata (Hertlein) (p. 39). Holotype of Ostrea cierboensis Grant and Eaton UCLA 8980. Cierbo Formation, California, Miocene. Crassostrea columbiensis (Hanley) (p. 37). Holotype of Ostrea corteziensis Hertlein CAS 4288 ( X 0.8). Bahia Kino, Golfo de California, Sonora Mexico, Holocene. Striostrea? freudenbergi (Hertlein and Jordan) (p. 34). Holotype CAS/SU 5138. Isidro(?) Formation, Baja California Sur, Miocene. Striostrea? bourgeoisii perrini (Hall and Ambrose) (p. 35). Holotype CAS/SU 502 ( X 0.7). Briones Formation, California, Miocene. Striostrea? bourgeoisii bourgeoisii (Re’mond) (p. 34). Hypotype of Clark (1915, pl. 43) UCMP 11566 ( X 0.5). San Pablo Formation, California, Miocene. GEOLOGICAL SURVEY CRASSOS TREA, CRASSOS TREA ?, S TRIOS TREA ? PROFESSIONAL PAPER 1228-C PLATE 26 FIGURES 1. 4 PLATE 27 " Crassostrea? eucorrugata (Hertlein) (p. 39). Holotype UCMP 11309 ( X 0.4). Santa Margarita Formation, California, Miocene. . Crassostrea? californica osunai (Hertlein) (p. 40). 1 Holotype CAS 12823 ( x 0.5). Salada Formation, Baja California Sur, v‘ Pliocene. Striostrea? freudenbergi (Hertlein and Jordan) (p. 34). Holotype CAS/SU 5138. Isidro(?) Formation, Baja California Sur, Miocene. Crassostrea titan (Conrad) (p. 35). Holotype of Ostrea titan prior Grant and Eaton UCLA 8991. Branch Canyon Sandstone, California, Miocene. Striostrea? bourgeoisii perrini (Hall and Ambrose) (p. 35). Holotype CAS/SU 502. Briones Formation. California, Miocene. 4 { GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-0 PLATE 27 CRA SSOS TREA, CRASSOS TREA ?, S TRIOS TREA .9 PLATE 28 FIGURES 1, 2, 4. Crassostrea columbiensis (Hanley) (p. 37). Holotype of Ostrea corteziensis Hertlein CAS 4288 ( X 0.8). Golfo de California, Sonora Mexico, Holocene. 3, 5. Crassostrea titan (Conrad) (p. 35). Holotype of Ostrea ligminuta Grant and Eaton, UCLA 8985 (X 0.8). Branch Canyon Sandstone, California, Miocene. PROFESSIONAL PAPER 1228-C PLATE 28 GEOLOGICAL SURVEY CRASSOS TREA FIGURES 1, 6. 3-5. 7, 8. PLATE 29 Crassostrea titan (Conrad) (p. 35). 1. Holotype of Ostrea titan prior Grant and Eaton, UCLA 8991. Branch Canyon Sandstone, California, Miocene. 6. Holotype of Ostrea ligminuta Grant and Eaton, UCLA 8985 ( X 0.8). Branch Canyon Sandstone, California, Miocene. “Ostrea” weaveri Dickerson (p. 29). Holotype UCMP 32624. Martinez Formation, California, Paleocene. Acutostrea idriaensis idriaensis (Gabb) (p. 31). 3, 5. Holotype of Ostrea haleyi Hertlein CAS 5526. Canada Formation, Santa Cruz Island, California, Eocene. 4. Photograph copied from Gabb (1869, pl. 34, fig. 103a). Striostrea? tayloriana (Gabb) (p. 33). Holotype UCMP 12005. Gaviota Formation, California, Eocene and Oligocene. (vv AVAA ‘_ GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—C PLATE 29 CRASSOS TREA, “OS TREA ”, A CU TOS TREA , S TRIOS TREA? PLATE 30 FIGURES 1—4, 6, 8. Ostreola conchaphila (Carpenter) (p. 28). 1, 3. CAS 057760 ( X 1.5). Olympia, Washington, Holocene. 2, 4. CAS 057761 ( X 1.5). Olympia, Washington, Holocene. 6, 8. Hypotype of Howard (1935, pl. 7, fig. 5) CAS 7044 ( X 2.0). San Joaquin Formation or upper part of Etchegoin Formation, California, Pliocene. 5. Acutostrea idriaensis fettkei (Weaver) (p. 30). Holotype of Ostrea buwaldana Dickerson UCMP 11719. Martinez Formation, California, Paleocene. 7, 9. Ostrea (Ostrea) atwoodii Gabb (p. 28). Hypotype of Durham and Addicott (1965, pl. 3, figs. 3, 7) USNM 649094. Pancho Rico Formation, California, Miocene. 4—11. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-C PLATE 30 OS TRE OLA, A CU TOS TREA, OS TREA PLATE 3 1 FIGURES 1-6, 8. Dendostrea? angermanni (Hertlein and Jordan) (p. 25). 1-4, 6. Hypotype UCMP 37535 ( X 1.5). Imperial Formation, California, Miocene or Pliocene. 5, 8. Holotype CAS/SU 5137 ( X 1.5). Isidro(?) Formation, Miocene. 7. Ostreola? venturana (Loel and Corey) (p. 29). Paratype UCMP 10035 ( x 1.5). Vaqueros Formation, California, Oligocene and Miocene. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-C PLATE 31 DENDOS TREA ?, OS TRE OLA ? FIGURES 1, 8, 9. 2, 5. 3, 7. 4, 6. PLATE 32 Dendostrea? angelica (Rochebrune) (p. 26). 1, 8. Hypotype CAS 057786. Golfo de California, Holocene. 9. Hypotype of Durham (1950, pl. 5, fig. 7) UCMP 15955. Marquer Formation, Baja California Sur, Pliocene. Ostreola? megodon (Hanley) (p. 29). 2. Hypotype of Jordan and Hertlein (1926b, pl. 28, fig. 1) CAS 2093. Almejas Formation, Baja California Norte. 5. Lectotype of Ostrea cerrosensis Gabb AN SP 4494. Almejas(?) Formation, Baja California Norte, Pliocene. Neopycnodonte? cf. N. cochlear (Poli) (p. 23) Hypotype of Ostrea cumingiana Dunker of Durham (1950, pl. 5, fig. 4) UCMP 15425. Marquer Formation, Baja California Sur, Pliocene. Acutostrea idriaensis fettkei (Weaver) (p. 30). Holotype of Ostrea crandalli M. A. Hanna UCMP 31072 ( X 1.5). Delmar Formation, California, Eocene. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-C PLATE 32 DENDOS TREAZ OS TRE OLA ?, NE OP YCN ODON TE ?, A CU TOS TREA PLATE 33 FIGURES 1-3, 8. Acutostrea idriaensis fettkei (Weaver) (p. 30). 1, 3. Holotype CAS 479 ( X 3.0). Cowlitz Formation, Washington, Eocene. 2, 8. Paratype CAS 479a ( X 3.0). Cowlitz Formation, Washington, Eocene. 4, 6, 7, 9. Acutostrea? miguelensis (Hertlein) (p. 32). 4, 6. Holotype CAS 4121 ( X 3.0). Vaqueros Formation, California, Oligocene and Miocene. 7, 9. Paratype CAS 4122 ( X 3.0). Vaqueros Formation, California, Oligocene and Miocene. 5. Ostreola? venturana (Loel and Corey) (p. 29). Holotype UCMP 31751 ( X 3.0). Vaqueros Formation, California, Oligocene and Miocene. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228C PLATE 33 8 A C U TOS TREA, ACUTOS TREA ?, OS TRE OLA .9 PLATE 34 FIGURES 1, 3, 6, 8. Ostreola? megodon (Hanley) (p. 29). 1, 3. Hypotype of Jordan and Hertlein (1926b, pl. 28, fig. 1) CAS 2093. Almejas(?) Formation, Baja California Norte, Pliocene. 6, 8. Holotype of Ostrea cerrosensis Gabb AN SP 4494. Almejas(?) Formation, Baja California Norte, Pliocene. 2, 7, 9, 10. Dendostrea? angelica (Rochebrune) (p. 26). 2. Hypotype of Ostrea cumingiana Dunker of Durham (1950, pl. 5, fig. 6) UCMP 15424. 7, 9. Hypotype CAS 057762. Golfo de California, Holocene. 10. Hypotype of Ostrea vespertina Conrad of Durham (1950, pl. 5, fig. 7) UCMP 15955. Marquer Formation, Baja California Sur, Pliocene. 4, 5. Acutostrea simiensis (Zinsmeister) (p. 30). 4. Holotype UCR 6899/101. Simi Conglomerate, California, Paleocene. 5. Paratype UCR 6899/102. Simi Conglomerate, California, Paleocene. 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E-146, 701 C St. Maps Maps may be purchased over the counter at the U.S. Geologi- cal Sm'vey offices where books are sold (all addresses in above list) and at the following Geological Survey offices: - ROLLA, Mlssouri--1400 Independence Rd. 0 DENVER, Colorado--Map Distribution, Bldg. 810, Federal Center 0 FAIRBANKS, AIaska-—New Federal Bldg., 101 Twelfth Ave. Tertiary Marine Pelecypods of California and Baja California: Lucinidae through Chamidae By ELLEN JAMES‘i MOORE \ PALEONTOLQGY OF CALIFORNIA AND BAJA CALIFORNIA I " I I U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—D I w A total of 63 species and subspeciex representing 25 genera in the families Lucini‘dae, Thyasirza’ae, Ungulinidae, and . Chamidae are illustraied, taxonomy revised and updated, geographic and geologic ranges given, occurrence by geologic formation cited, and liabitat included when it can be confidently inferred I . I I ’ UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1988 DEPARTMENT OF THE INTERIOR DONALD PAUL HODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Library of Congress Cataloging-in-Publication Data Moore, Ellen James. Tertiary marine pelecypods of California and Baja California. (Paleontology of California and Baja California) (U.S. Geological Survey professional paper ; 1228-D) Bibliography: p. D34 Includes index. Supt. of Docs. no.: I 19.1621228-D 1. Bivalvia, Fossil. 2. Paleontology—Tertiary. 3. Paleontology—California. 4. Paleontology—Mexico—Baja Califor- nia. I. Title. II. Series. III. Series: Geological Survey professional paper ; 1228—D. QE811.M635 1988 564'.11'09794 88-600027 For sale by the Books and Open-File Reports Section, US. Geological Survey, Federal Center, Box 25425, Denver, CO 80225 ej‘ A) Page Abstract ___________________________ D1 Introduction _________________________ 1 Purpose and scope — — — __________________ 1 Procedure _________________________ 1 Acknowledgments — — — __________________ 6 Abbreviations _______________________ 6 Systematics: Pelecypods—C ntinued from Chapter C ————— 7 Family Lucinidae — — — __________________ 7 Subfamily Lucininae __________________ 7 Genus Lucina — — __________________ 7 Subgenus Lucim _________________ 7 Subgenus Luc'imsca _______________ 9 Genus Lucina? ___________________ 10 Subgenus Lucm L? ________________ 10 Genus Callucma — __________________ 10 Subgenus Calluc’na _______________ 10 Genus Codakia — __________________ 11 Subgenus Codak a ________________ 11 Subgenus Epiluc ’na _______________ 11 Genus Ctena — — — __________________ 12 Subgenus Ctena _________________ 12 Genus Here — — — __________________ 12 Subgenus Here __________________ 12 Genus Linga — — __________________ 13 Subgenus Pleurolucina ______________ 13 Genus Pamilucina _________________ 14 Subgenus Pamil tcina ______________ 14 Genus Anodontia __________________ 15 Subgenus Anodont'ia ——————————————— 15 Genus Amdontia? _________________ 16 Subgenus Anodo tia? _______________ 16 Subfamily Myrteinae _________________ 16 Genus Myrtea — — _________________ 16 Subgenus Myrte _________________ 16 Genus Lucinoma — _________________ 16 Subfamily Milthinae _________________ 17 Genus Miltha ____________________ 17 Subgenus Miltha _________________ 18 Subgenus Miltha _________________ 19 Genus Claibomites _________________ 19 Subgenus Claibo ‘n’ites ______________ 19 PLATES 1. Lucina, Anodcntia?, Codakia. Codak’ia, Cten L, Here. Here, “Lucina ’, Callucina. Lam'mma, Pa’rm'lucma, Lucinal Myrtea, Lingo. Miltha, “Luci ‘ a”. Miltha, Claibo ites, Gibbolucina. Diplodonta, A inops'ida, Bruetia?, Felam'ella. Felam‘ella, Ch ma, Miltha, Pseudochama. Chama, Pseud chama, Felam'ella, Arcinella. FPPWNQP‘FWN HH CONTENTS Genus Claiborm'tes—Continued Page Subgenus Codalucma _______________ D20 Genus Gibbolucina __________________ 20 Subgenus Eomiltha ________________ 20 Subgenus Eom'iltha? _______________ 21 Genus Myrtucina __________________ 21 Genus Pegophysema _________________ 21 Subgenus Pegophysema ______________ 21 Subfamily Divaricellinae ________________ 22 Genus Divam’cella __________________ 22 Genus Diva’r‘icella? _________________ 22 Subgenus Eg’racina ———————————————— 22 Subgenus Eg'rac'ma? _______________ 22 Genus Divalinga ___________________ 22 Subgenus Divalinga, _______________ 22 Family Lucinidae? _____________________ 23 Genus uncertain ____________________ 23 Family Thyasiridae ____________________ 24 Genus Thyasz'm ____________________ 24 Subgenus Thyasira _________________ 24 Subgenus Conchocele _________________ 24 Genus Adontorhma ___________________ 25 Genus Axinopsida ___________________ 25 Family Ungulinidae ____________________ 26 Genus Bmetia _____________________ 26 Genus Bruetia? _____________________ 26 Genus Diplodonta ___________________ 26 Subgenus Diplodonta ________________ 26 Subgenus Zemysina _________________ 28 Genus Felaniella ____________________ 28 Subgenus Felam‘ella _________________ 28 Family Chamidae _____________________ 30 Genus Chama _____________________ 30 Subgenus Chama __________________ 30 Subgenus Chama? —————————————————— 31 Genus Arcinella ____________________ 31 Genus Pseudochama __________________ 31 Subgenus Pseudochama _______________ 32 Fossil localities ________________________ 32 Geologic formations cited for occurrence of pelecypods — — — — 33 References __________________________ 34 Index ————————————————————————————— 41 ILLUSTRATIONS [Plates follow index] Gibboluc'ma, laibomites, Myrtucma, Thyasz'ra, Divaficella7, Divalinga, Lucina, Diplodonta, “Lucina”. Chg/ma, “Luci‘na”, Am'nopsida, Pseudochama, Pegophysema, Adontorhina. III IV CONTENTS FIGURES 1. Divisions used in California for geographic ranges of species of pelecypods, Lucinidae through Chamidae ——————— 2. Divisions used in Baja California Peninsula for geographic ranges of species of pelecypods, Lucinidae through Chamidae —————————————————————————————————————————————————————— TABLE S TABLES 1—5. Geologic and geographic distribution of the genera: Lucinal Callucma, Codakia, Cte'na, Here, Linga ———————————————————————————————— Parm'lucina, Anodontia, Myrtea, Lucinoma, Miltha, Claiborm'tes ———————————————————————— Gibboluc'ma, Myrtucma, Pegophysema, Divar’icella?, Divalmga, “Lucina” ———————————————————— Thyasi'ra, Adonto'rhma, Axinopsida, Bmetial Diplodonta, Felamlella ————————————————————— 1. 9"wa Chama, Arcmella, Pseudochama Page D2 Page WQOfiU‘A PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA TERTIARY MA INE PELECYPODS OF CALIFORNIA AND BAJA CALIFORNIA: LUCINIDAE THROUGH CHAMIDAE ABSTRACT The description of the mollusks in the Tertiary formations of Califor- nia and Baja California is cont nued from Chapter C. Sixty-three species and subspecies in the families Lucinidae, Thyasiridae, Ungulinidae, and Chamidae, representing 25 genera, are covered in this chapter. 0f the 25 included genera, 4 occur In the Paleocene, 10 in the Eocene, 4 in the Oligocene, 6 in the Miocer e, 9 in the Pliocene, 9 in the Pleistocene, and 9 in the Holocene of the ir eluded geographic area. Four genera are extinct. INTRODUCTION PURP SE AND SCOPE The description and i1 ustration of the Tertiary marine mollusks of California and Baja California started in Chapter A is continued in this chapter, which treats the families Lucinidae, Thyasiridae, Ungulinidae, and Chamidae. A total of 63 species ssigned to the included families occur in the geographi study area. For convenience of reference, the figures s owing the geographic divisions used for the Californias are reproduced here (figs. 1, 2). P OCEDURE All Tertiary marine m llusks originally described from California and the Baja California peninsula, and all species originally descri ed from other geographic local- ities but known to occu in the Tertiary of the Califor- nias, are included in this study. All positively identified species that have been, found on fauna] lists are also included. Only in gener that are extremely rare, have I included species that re questionably identified. In this work, the spe ies are arranged systematically following the order of amilies, genera, and subgenera given in the Treatise (M ore, 1969). Within the systematic groups, species are arranged by geologic age, beginning with the oldest species and ending with the youngest. Brief synopses of generic and subgeneric characters are given in the appropriate places; more complete synopses Publication authorized by the Directcr, U.S. Geological Survey, April 29, 1987. By ELLEN JAMES MOORE will be found in the Treatise (Moore, 1969), in Keen (1971), and in Olsson (1961). Distribution tables are included to show graphically the geographic and geologic distribution of species within each family. To facilitate finding a specific taxon, the species are listed alphabetically under genus and subgenus in the tables. The synonymy for each species includes the original cita- tion and subsequent substantive references. The accuracy of identifications cited in subsequent references in the synonymy has not been verified. The type is usually that of the author of the original description or of later workers who selected a lectotype or neotype. If the original locality description is so vague that it is of little use, the type locality is described as corrected or modified by other workers such as Keen and Bentson (1944) and the modifications given within brackets. All other localities are cited as originally described except the formation name given is that currently being used. Previously published supplementary descriptions and comparisons are included and I have supplemented this in the section headed “Comments”. For most descrip- tions, my comments are based only on examination of primary type material. All available published data for each species have been included in the section on geographic and geologic age range, including that contained in fauna] lists when the identification is unqualified. Age ranges have not been refined within epochs. If a stage name the same as a for- mation name is used, it is placed in quotes to distinguish it from the rock unit. The divisions used here to indicate the approximate geographic range of species within California based on county distribution are northern, middle, and southern (fig. 1); the divisions for the Baja California Peninsula, norte and sur (fig. 2; tables 1—5). An attempt has been made to include all citations to a species that are unqualified and every geologic formation in which it is reported to occur in the Californias. The assumption has been made that all identifications of species are correct unless there is strong evidence to the contrary. The stratigraphic nomenclature used herein is D1 D2 PALEONTOLOGY OF CALIFORNIA AND BAJ A CALIFORNIA 42° 2 0: Lu HUMBULDT I l- I o 2 39° _ ‘1 > o LU _l D —- 9 2 ’fi 3 125° 120° 115° I l SANTA BARBARA 'Z 2 cc . LOS ANGELES UIJ Santa Cruz I a _ Island ' 4 S San Miguel Island 4 v1; I 8 Santa Rosa Island ,’ ' -—— I I: I ’ Sam: . I'Calalinm ' San Nicolas Island %. II Island i I l l I 0 5° 100 150 200 KILOMETERS San Clemente Island\ '. l SAN DIEGO IMPERIAL FIGURE 1.—Divisions used in California for geographic ranges of species of pelecypods, Lucinidae through Chamidae. a TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE 32° ._ 30° 218‘ 24 1 116° 114° 112° 110° 1 I I r 1 Sar1 Diego 1 L Corqfinados CALIFORN A 2 “1m“ -_ “ " ARIZONA 1 ‘\ \‘ \ Ensenad.‘ (/ ‘\’Vlr U) Q A;\O\Sr4 v 8470an ‘. ~ 1 ° ‘\ v \ 1 o \‘-—--———_- O O San1Quintin 7 O ( r V / 1 Rosario 4 m 't: O O 5) > 1, lsla Angel ‘1 / de la Guarda n 1 7 1 o O 9 1 Bahia ’9 a o 1513 1 lsla Geckos!) Sebastian A Tiburon 1 Vizcafno 6‘ ° ('3 11 0 w Bahfa Tdrtola 7 — ( , O 1 A 1 Buhl’u O Conrepribn ‘9 \ 0 Laguna San Ignacio O 1 T. 1 37 _ 2 Q a 1 1 1 1_ 1 mlsla Cerralvo 1 1 —. 0 50 100 150 200 KILOMETERS 1 Cabo San Lucas 1 J 1 FIGURE 2.—1Divisi0ns used in Baja California Peninsula for geographic ranges of species of pelecypods, Lucinidae through Chamidae. D3 D4 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA that of the author(s) cited and does not necessarily agree with that of the U.S. Geological Survey. The age given for the stratigraphic units follows the classification of geologic time currently used by the U.S. Geological Survey. (See “Geologic Formations Cited for Occurrence of Pelecypods” at end of paper.) Each formation listed is followed by the name of the author and date of publica- tion of the work from which it was obtained. More than one reference to a formation is given where it might be useful to the reader. The list of formations given for species occurrence should not be considered complete nor necessarily accurate. Many western American Tertiary faunas have not been included in a monograph, therefore their species content is not fully known. It is hoped that the list of formational occurrences reported will serve as a framework upon which the true distribution of each species can be built. The type specimens were all photographed by Kenji Sakamoto, U.S. Geological Survey. Owing to the fact that the specimens photographed were borrowed from other institutions, Sakamoto did not use his usual technique of opaquing specimens for photography (Sakamoto, 1973). The holotype of each Tertiary species is figured if the type is extant. Holocene type specimens have not been figured; TABLE.1.—Geologic and geographic distribution of the genera Lucina, Lucina?, Callucina, Codakia, Ctena, Here, and Linga in the eastern Pacific region [HzHolocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; O=Oligocene; Eoncene; Pa=Paleocene] Species California Central or South Baja California Northern Middle Southern Norte Sur America Genus Lucina Subgenus Lucinisca menuda (Keen) ................................... nuttallii antecedens (Arnold) ........... nuttallii nuttallii (Conrad) .............. Genus Lucina? Subgenus Lucina? bramkampi Vokes ............................ diaboli (Dickerson) ......................... quadrata (Dickerson) .................... Pa Genus Callucina Subgenus Callucina lampra Dall ...................................... ling ualis (Carpenter) ....................... Genus Codakia Subgenus Codakia distinguenda (Tryon) ....................... Subgenus Epilucina californica (Conrad) .................... H Genus Ctena Subgenus Ctena mexicana (Dall) .............................. Genus Here Subgenus Here effingeri (Weaver and Kleinpell).. """ excavata (Carpenter) ....................... hannai (Clark) ............ Genus Linga Subgenus Pleurolucina cancellaris (Philippi) ...................... .... M to ple ............... MtoH Ple andH Pa ............... Pa .................... PltoH PltoH a: PltoH H P1 to H Pie and H """ MtoH H .... E and O ............... MtoH H b 1 ‘ l TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D5 l specimens considered to be of the same species by authors Most of the data on habitat have been compiled from such as Durham (1950) an‘d Hertlein and Grant (1972) are Abbott (1974), Bernard (1983), Hertlein and Grant (1972), used for these illustrations, and this information is Keen (1971), Smith and Gordon (1948), Stanley(1970), and included in the plate exfilanation. Yonge and Thompson (1976). 1 TABLE 2‘.——Geologic and geographic distribution of the genera Parvilucina, Anodontia, Myrtea, Lucinoma, Miltha, and Claibornites in the eastern Pacific region l [H=Holocene; lPlezPleistocene; Pl=Pliocene; MzMiocene; O=Oligocene; E=Eocene; Pa=Paleocene] l Alaska British Wash- Oregon California Baja California Central or South ‘ Colum— ington l bia Species 1 Northern Middle Southern Norte Sur America Genus Parvilucina ‘ Subgenns Parvilucina l H H H M to H H approximata (Dall)... tenuisculpta, intensa (Dall) ....... teniseulpta ‘ tenisculpta (Carpenter) ........ Genus Anodontid? Subgenus Anqdontia? l inflata (Wagner i l E ............... and Schilling) ------ .l .............................. Genus Myrtea Subgenus Myrtea ‘ taffana (Dickerson).J """ Genus Lacinoma ‘ acutilineata (Conrad) .............. l annulata (Reeve) ...... ‘l H H Genus Miltha l Subgenus Miitha l parsoni Waring ................ Pa ............... sanctaecrujcis .......... pl [0 P16 n... n... H MtoH MtoH H H """ .......... Pa and E ..... ..... OandM """ OandM OandM Mto Ple Eto Ple Oto Ple """ H H P1 to H M to H M to H H H """ (Arnold) ............. l‘ """""""" O and M M to Ple """ xantusi (Dall) ........ l. """""" M M to Ple H P1 to H “““ Subgenus Miltha? jacalitosama (Arnold) ............. , meganosensis ‘1 (Clark and ‘ l .......... Pa .................... Woodford) ....... ‘ """""""""" Genus Claiborinites ‘ Subgenus Claibornites diegoensz'.i i (Dickerson) ....... l” Subgenus Codalucina ‘1 muzrensis: .......... M a“(1 P1 ..... n... (DiCketson) ........ l ........................... Pa .......... l Stanton)..\ ........ l turneri l l l D6 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA ACKNOWLEDGMENTS The late A. Myra Keen, Santa Rosa, Calif, and John G. Vedder, US. Geological Survey, reviewed the manu- script, and their pertinent suggestions were most helpful. Charles L. Powell II asSisted in making prints and in com- piling data. The following individuals made available or loaned type material for study and photography; Frederick J. Collier, National Museum of Natural History; Thomas A. Deméré, San Diego Museum of Natural History; Carol C. Jones, Academy of Natural Sciences of Philadelphia; Marilyn Ann Kooser, University of California at Riverside; David R. Lindberg, University of California at Berkeley; LouElla Saul, University of California at Los Angeles; Robert Van Syoc, California Academy of Natural Sciences; Jann W.M. Thompson, National Museum of Natural History; Edward C. Wilson, Los Angeles Museum of Natural History. ABBREVIATIONS ANSP: The Academy of Natural Sciences of Philadelphia, Philadelphia, Pa. BM(NH): British Museum of Natural History, London, England. CAS: California Academy of Sciences, San Francisco, Calif. LAM: Los Angeles County Museum of Natural History, California. LACMP: Los Angeles County Museum of Paleontology MCZ: Harvard Museum of Comparative Zoology, Cam- bridge, Mass. SDNM: San Diego Natural History Museum, California. CAS/SU: Stanford University, Stanford. Calif. [Stanford University collections are now in the California Academy of Sciences] SU: Stanford University, Stanford, Calif. UC: University of California, Berkeley. UCMP: University of California, Museum of Paleontology, Berkeley. UCR: University of California at Riverside. USGS: US Geological Survey, Washington, DC, Ceno- zoic locality register. USGS M: US. Geological Survey, Menlo Park, Calif, Cenozoic locality register. USNM: National Museum of Natural History, Washing- ton, D.C. UW: University of Washington, Seattle. TABLE 3.—Geologic and geographic distribution of the genera Gibbolucina, Myrtucina, Pegophysema, Divaricella?, Divalinga, and “Lucina” in the eastern Pacific region [I{=Holocene; Ple=Pleistocene; P1=Pliocene; M=Miocene; O=Oligocene; E=Eocene; Pa=Paleocene] Species Oregon Central or South California Baja California Northern Middle Southern None Sur America Genus Gibbolucina Subgenus Eomiltha gyrata (Gabb) ...................................... Subgenus Eomiltha? packi (Dickerson) ........................ Genus Myrtucina roseburgensis (Turner) ................ E ..... Genus Pegophysema Subgenus Pegophysema edentuloides (Verrill) ....................... Genus Divaricella? Subgenus Egracina? cumulata (Gabb) ................................. Genus Divalinga Subgenus Divalinga eburnea (Reeve) ............................ """ Genus "Lucina" gaylordi (Wagner and Schilling).. """"" nasuta (Gabb) ........................................ wattsi Loel and Corey .................. ----- M or P1 H Ple and 11 H ..... E ..... ..... ..... l ‘ TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D7 l l SYSTEMATIC S' PELEG‘YPODS—CONTINUED FROM lamellae with some areas smoother than remainder of disc. Hinge with ' cardinal teeth and sometimes with laterals. CHAPTER C Geologic range—Upper Cretaceous to Holocene. ‘l Habitat—15 to 7225 m in the eastern Pacific (Hertlein and Grant, Family LUCINIDAE 1972, p. 243). ‘ Subfamily LUCININAE Genus LUC NA Brugulére, 1797 Subgenus LUCINA l Medium-sized to large, orb cular in outline, more or less flattened, valves closed withlwell-marked dorsal areas; lunule usually well devel- oped, no escutcheon; sculpture of somewhat evenly spaced concentric ‘ l TABLE 4.—Gleologic and geographic distribution of the genera Thyasira, Adontorhina, Axinopsida, Bruetia?, Diplodonta, and Felaniella in the eastern Pacific region Concentric lamellae well spaced, stronger posteriorly, dorsal areas clearly marked; lunule asymmetrical, elongate, narrow. Geologic range—Upper Cretaceous to Holocene. l l [H=Holocene; Ple=Pleistocene; P1=Pliocene; M=Miocene; O=Oligocene; E=Eocene; Pa=Paleocene] l l Species l Alaska British Wash- Oregon l Colum- ington bia California Baja California Central or South Northern Middle Southern Norte Sur America Genus Thyasira Subgenus Thyasira ‘ gouldii (Phlllippi)...., Subgenus Conchocele disjuncta (Gabb) ....... ‘ folgeri (Wagner and Schilling) ............... ‘ """ Genus Adontorhi‘na cyclia Berry Genus Axinopsida serricata ‘ (Carpenter) ........... ‘ viridis (Dall) ........... l. H Genus Bruetia? l traski (Nelson)........l ---------------- Genus Diplodonta i Subgenus Diplodonta‘ l buwaldana. Anderson‘ and Martin ........... l ------------------------- O and M M to Ple Ple """ Cretacea (Gabb) ------- 1' ............... Pa E ............... orbella (Gould) ....... l. ------------------------- o to H P1 to H Plc and H Ple and H ----- ..... Pa E u... ..... u... polita (Gabb) ........... l """"""""""" l xtephensoni C1ark..l.. ......................... MO) ............... subquadrata ‘i H H H H H H p1 to H .......... H H O to H O to H """"" P1 and P16 ......................... E and O ..... u... ..... l H H H H H H MtoH H .......... P16 and H Ple and H H H P1 to H H M to H H [)1 H H H H H P1 to H ..... ..... ..... pa n... u... Carpenter ............ l --------------------- unisulcatus (Vokesiu """ Subgenus Zemysina l pacifica l‘ Zinsmeister ......... l... Genus Felaniella i Subgenus Felaniella l cornea (Reeve) ....... l """"""""""""""""""" P1 to H H P1 to H H harfordl' (Andersod).. ......................... M O to P1 ............... parilis (Conrad)....l... O(?) and M(?) """ O and M O and M """ M and P M and P ---- D8 Lucina? (Lucina?) diaboli (Dickerson) Plate 4, figures 9, 15, 18 Phacoides diaboli Dickerson, 1914, p. 132—133, pl. 10, fig. 7. Original description—“Shell thin, equivalve, suborbicular, nearly equilateral; beaks prominent, prosogyrate, central; valves convex; lunule narrow and extending half the length of the straight horizontal anterior dorsal margin; escutcheon narrow, two-thirds the length of the straight sloping posterior dorsal margin and set off in each valve by a high, sharp ridge from rest of shell. A rounded ridge extends from the beaks to the middle of the posterior end; the portion of shell between the umbonal ridge and the ridge bordering the escutcheon is slightly concave; sculp- ture consists of sharp concentric lamellae with interspaces about three times their width.” Holotgpe.—UCMP 11681. Type locality.—UC 340. “SE1/4NE1/4, T. 1 S., R. 1 W., Mt. Diablo quad, Contra Costa Co.” (Keen and Bentson, 1944) Martinez Formation, Paleocene. Comparison—“The sculpture resembles that of P. [hacoides] acuti- lineatns (Conrad) but its height is proportionally much less than that of P. acutilineatns. Its long lunule and escutcheon are also distinctive features.” (Dickerson, 1914, p. 133) Comments.—The hinge is not exposed on the holotype of Lucina? (anina?) diaboli. The species is placed in anina? on the basis of its asymmetrical lunule, outline, and sculpture. Geographic range—Middle California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Dickerv son, 1914). Lucina? (Lucina?) quadrata (Dickerson) Plate 4, figure 11 Phacoides quadrata Dickerson, 1914, p. 131—132, pl. 10, fig. 6. Original description—“Shell thin, compressed, markedly quadrate, high; beaks rounded, prosogyrate; posterior dorsal margin straight, PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA sloping moderately to the straight posterior end, which is nearly parallel to altitude line; anterior dorsal margin very slightly convex; anterior end nearly straight; ventral margin rounded; sculpture consists of raised sharp incremental lines with interspaces about three times their widt .” Holotype.—UCMP 11683. Type locality.—UC 784. Lake County, Calif. Martinez Formation, Paleocene. Geographic range—Northern and middle California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Dicker- son, 1914). Lucina? (Lucina?) bramkampi Vokes Plate 4, figure 10 anina(?) sp. Dickerson, 1916, p. 426. Lucina(?) bramkarnpi Vokes, 1939, p. 71, pl. 10, fig. 9. Original description—“Shell small, subcircular in outline, thin; umbo central, slightly prosogyrous; anterior dorsal edge straight; posterior dorsal margin slightly convex; anterior and ventral margins broadly rounded, the posterior straight; a well-defined groove running from the umbo to the anterior dorsal margin, a less well—defined groove to the posterior end; surface with a series of step-like concentric ridges overlap— ping toward the beak, no incremental lines or radial ribbing visible; interior not seen.” Holotype.—UCMP 15629. Type locality.—UC 1817. Fresno County, Calif. Cerros Shale Member, Lodo Formation, Paleocene. Comparison—“L. bramkampi may be distinguished from all described West Coast lucinoid species by the overlapping, step-like character of the sculpturing.” (Vokes, 1939, p. 71) Geographic range—Middle California. Geologic range—Paleocene and Eocene. Occurrence in California—Paleocene: Cerros Shale Member, Lodo Formation (Keen and Bentson, 1944); Eocene: Ragged Valley Shale Member, Arroyo Hondo Formation (Vokes, 1939). TABLE 5.——Geologic and geographic distribution of the genera Chama, Arcinella and Pseudochama in the eastern Pacific region [H=Holocene; Ple=P1eistocene; P1=Pliocene; M=Miocene; O=Oligocene] Species Oregon California Baja California Central or Soufli Northern Middle Southern Norte Sur America Genus Chama Subgenus Chama arcana Bernard ........................... H H M to H P1 to H Ple and H Ple and H ---- echinaza Broderip ................................... M to H H frondora Broderip ............................. M or P1 P1 to H P1 to H H squamuligera Pilsbry and Lowe. """""""""" H MtoH H Subgenus Chama? sp. Loel and Corey ............................... OandM """""""" Genus Arcinella californica (Dall) ................................. M or P1 H H H Genus Pseudochama Subgenus Pseudochama exogyra (Conrad) ......................... H H H P1 to H Ple Ple """ 1 subgemls LUCINISCA Sculpture reticulate, lunule lsomewhat depressed and only slightly asymmetric, and inner margiri strongly denticulate. Geologic range—Miocene tol Holocene (table 1). Habitat—In warm temperatei and tropical marine waters, intertidally to 185 m (Hertlein and Grant,‘ 1972, p. 244). Lucina (Luciriisca) menuda (Keen) Platesl, figures 1, 2 Lucinisca menuda‘Keen, 1943, p. 40—41, pl. 3, figs. 15, 16. Original descriptum.—“Shelllsmall, nearly circular in outline; sculpture of radial and concentric riblets which intersect as beads, more closely spaced on posterior slope thah on central and anterior parts of shell (somewhat obscure‘d in holotyiie by an incrustation of sand grains which could not be removed); beak nearly central, dorsal margin sloping downward at a low angle; p0 terior margin somewhat truncate, join- ing dorsal at an angle of about y degrees; ventral and anterior margins evenly rounded; margins cren ated by the ends of the radial ribs; muscle scars subequal, pallial line en ire; hinge of left valve strong, with two anterior lateral teeth, two sube ual cardinal teeth, and a double posterior lateral tooth or clasper; right valve not available.” Holotype.——CAS/SU 7526. ‘ Type localitg.—SU 2121. Kern County, Calif. Round Mountain Silt, Miocene. Comparison—“From the West American Recent species Lucinisca nuttalli (Conrad) this [L. (L.) lmenuda] is distinguished by the truncate posterior margin and the morle attenuate anterior margin. Possibly L. menuda may be the Luciniscal aff. L. nuttalli (Conrad) recorded by Loel and Corey***, 1932, p. 210)‘l‘**.” (Keen, 1943, p. 40) Geographic range—Southern California. Geologic range—Miocene. l Occurrence in Californiai-Miocene: Round Mountain Silt (Keen, 1943). ‘l Lucina (Lucinisc ) nuttallii nuttallii Conrad Plate 1‘, figures 3—6, 9, 12 Lucina nuttallii Conrad, 1837, p. 255, pl. 20, fig. 2. Arnold, 1903, p. 132—133. 1 Phacoides nuttallii Conrad. lI.S. Oldroyd, 1924, p. 5. Lucina (Mgrtea) nuttallii Co rad. Jordan, 1936, p. 132. Grant and Gale, 1931, p. 288, pl. 14, fig . 4a, 4b, 18. Lucina (Lucinisca) nuttallii Conrad. Hanna and Hertlein, 1943, fig. 64—10. Durham, 1950, p. 76, pl. 18, figs. 4, 5. Hertlein and Grant, 1972, p. 245-246, pl. 45 figs. 1—4; pl. 46, fig. 21. Lucinisca nuttall‘ii (Conrad). Moore, 1968, p. 40, pl. 18, fig. d. Adegoke, 1969, p. 114.. Addicott, 965, fig. 3d. Original description—“S ell lenticular, slightly compressed; disks cancellated; concentric line‘s very regular, lamelliform, prominent; anterior fold small, marginal; extremity emarginate above; cardinal and lateral teeth distinct; inner (margin minutely crenulated.” Types.—BM(NH) 61520.87. Two syntypes (Keen, 1966, p. 169). Type localitg.a—Inhabits muddy marshes near Sta.[ti0n] Diego, San Diego County, Calif. Holocene. Supplementary descriptidn.—“The evenly and sharply cancellated sculpture of thisispecies is characteristic. As in Lucina californica the lunule lies largely in one valve-the left, however, rather than the right.” (Jordan, 1936, p. 132) Comparison.-—“Lucina nulttalli centrifilga Dall, described as a variety from the Gulf of California, has the concentric lamellae near the beaks widely spaced, more elevat d [than L. nuttallii nuttallii] and fringed with flat spinules.” (Hertle n and Grant, 1972, p. 245) ‘TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D9 Comments.—Dorsal to the posterior ridge is a groove and the radials are wider between this groove and the dorsal margin. Two grooves are at the dorsal anterior margin; dorsal to the more ventral groove the concentric ridges are not cancellated and dorsal of this area the con- centrics are fluted to the dorsal margin. Geographic range—Living: southern California to Mexico; fossil: middle California to Baja California Sur; Japan? (Hertlein and Grant, 1972, p. 245). Geologic range—Miocene to Holocene. Occurrence in the Californias.—Miocene: Cierbo and Neroly Sand- stones (Hall, 1960), Pancho Rico (Mandra, 1960, 1963), and Santa Margarita (Nomland, 1917b; Preston, 1931; Addicott and Vedder, 1963; Adegoke, 1969) Formations; Miocene and Pliocene: Etchegoin (Adegoke, 1969), Purisima (Arnold, 1906, 1908), Tahana Member, Purisima (Addicott, 1969) and Towsley (Winterer and Durham, 1962; Kern, 1973) Formations; Pliocene: Carmen, Marquer (Emerson and Hertlein, 1964; Durham, 1950), Niguel (J .G. Vedder, written commun., 1978), and San Diego (Arnold, 1903; Hertlein and Grant, 1972; Rowland, 1972) Formations; Pliocene and Pleistocene: Fernando (English, 1914; Durham and Yerkes, 1964), Pico (Winterer and Durham, 1962), lower part of Fernando (Oakeshott, 1958), San Pedro (Arnold, 1903; TS. Oldroyd, 1924; Hanna and Hertlein, 1943) and Santa Barbara (Arnold, 1903) Formations; Pleistocene: Anchor Silt (Rodda, 1957), Timms Point Silt Member, San Pedro Formation (Clark, 1931), and unnamed strata at Baldwin Hills (W illett, 1937b), Capistrano Beach (Willett, 1937a), Carpinteria (Grant and Strong, 1931), Dune Terrace (Addicott, 1964), Goleta (Wright, 1972), Huntington Beach (Valentine, 1959), Potrero Canyon, Santa Monica Mountains (Hoots, 1931), Newport Bay (Kanakoff and Emerson, 1959), Pacific Palisades, Mission Bay (Kern and others, 1971), Signal Hill (DeLong, 1941), Torrey Pines, Tomalas Bay, Pacific Beach, Calif, northwestern Baja California (Valentine, 1957; Valentine and Rowland, 1969), Bahia Magdalena, Islas Coronados (Emerson and Hertlein, 1964), Laguna Scammon, Bahia San Quintin, San Ignacio, Baja California Norte (Grant and Gale, 1931; Durham, 1950; Jordan, 1926; Valentine, 1956, 1959, 1960b), and Bahia Tortola, Baja California Sur (Chace, 1956; Emerson and others, 1981). H abital.—On sand and mud intertidally to 46 m (Hertlein and Grant, 1972; Kern, 1973); 10 to 75 m (Bernard, 1983). Lucina (Lucinisca) nuttallii antecedens (Arnold) Plate 1, figures 7, 8, 10, 11; plate 7, figure 12 Phacoides nuttallii (Conrad) var. antecedens Arnold, 1907b, p. 436, pl. 55, fig. 6. Lucinisca nuttallii antecedens (Arnold). Woodring and Bramlette, 1950, p. 86, pl. 20, fig. 3; pl. 21, fig. 6. Lucina (Lucinisca) nuttallii antecedens (Arnold). Hertlein and Grant, 1972, p. 246, pl. 46, figs. 8, 9, 13, 14. Original description—“Shell averaging about 25 millimeters in longi- tude, very broadly elliptical in outline, longer than high, ventricose, and equivalve; beaks only moderately prominent, placed slightly anterior to middle of shell; base arcuate; anterior margin sloping more rapidly from beaks than posterior, the latter being nearly straight for about 6 or 8 millimeters from the beaks; both extremities quite regularly rounded, the posterior being possibly slightly more attenuate, sculpture consisting of numerous close-set subequal rounded radiating ridges and concentric ribs which are narrower than the radials, and spaced about twice the distance between two of the latter; the concentric ribs tend to become obsolete toward the periphery in adult specimens; the general appearance of the surface is decidedly cancellate. Lunule deep, small, and inconspicuous. Interior and hinge as in P. nuttallii.” Holotype.—USNM 165290. Type locality.—USGS 4471. Santa Barbara County, Calif. Careaga Sandstone, Pliocene. D10 Supplementary description—“The type of L. nuttallii antecedens is a poorly preserved left valve“ * ** As shown by a well-preserved left valve in Arnold’s collection from the type locality and by numerous specimens from other localities in the Santa Maria district, the umbo of this variety, and also of the living L. nuttallii, is sculptured with closely spaced concentric lamellae**** On the fossils the closely spaced lamellae are succeeded by widely spaced lamellae, more widely spaced than on the Recent form, and those in turn by lamellae of variable spacing.” (Woodring and Bramlette, 1950, p. 86) Comparison—Lucina nuttallii antecedens “is more ventricose, less angulated posteriorly, and its concentric ribs much wider spaced than typical P. nuttallii". (Arnold, 1907b, p. 436) “The widely spaced lamellae suggest L.[ucinisca] centrifitga, a Recent species from Lower California and the Gulf of California, but that species has widely spaced lamellae on the umbo. The type of L. nuttallii antecedens and other large specimens, notably a left valve from the Sisquoc formation at the Pennsylvania asphalt mine, are more inflated than the Recent L. nuttallii. That character, however, is not uniform.” (Woodring and Bramlette, 1950, p. 86) “from***an assemblage of a large number of individuals of L. nuttalli***it appears to us that the present subspecies is of doubtful value as a taxonomic unit.” (Hertlein and Grant, 1972, p. 246) Geographic range—Southern California. Geologic range—Miocene to Pleistocene. Occurrence in California.—Miocene: Topanga Formation (Takeo Susuki, written commun., 1981); Miocene and Pliocene: Purisima (Arnold, 1908) and Sisquoc (W oodring and Bramlette, 1950) Formations; Pliocene: Careaga Sandstone (Woodring and Bramlette, 1950), and Foxen Mudstone (Woodring and Bramlette, 1950) and San Diego Formation (Hertlein and Grant, 1972); Pliocene and Pleistocene: Fernando Formation (Arnold, 1907a). Genus LUCINA? Subgenus LUCINA? Lucina s. s, is not known living or fossil in the eastern Pacific. (Bernard, 1983; Gibson-Smith and Gibson-Smith, 1982) (table 1). Genus CALLUCINA Ball, 1901 Medium-sized to large, generally suborbicular; lunule slightly asym— metrical. Cardinals broad but weakened in some; shell margin minutely crenulate internally. Geographic range—Europe, Africa, Asia, North America, Australia. Geologic range—Cretaceous to Holocene (table 1). Subgenus CALLUCINA Rounded to trigonal, moderately convex; sculpture concentric, local- ly lamellose, more or less marked with weak intercalated radial ribs; lunule asymmetrical, not excavated. Cardinals commonly weakened; shell margin finely crenulate internally. Callucina (Callucina) lampra (Dall) Plate 3, figures 15, 16, 18, 20 Phacoides (Cavilucina) lamprus Dall, 1901, p. 811, 827, pl. 39, fig. 9. Lucina lampra (Dall). Jordan, 1936, p. 130. Lucina (Cardiolucina?) lampra (Dall). Durham, 1950, p. 7 6, pl. 18, figs. 1, 9. Lucino (Cavilinga) lampra (Dall). Olsson, 1961, p. 211, pl. 31, fig. 12. Lucina (Callucina) lompra (Dall). Keen, 1971, p. 120, fig. 268. Original description—“Shell of Dosinioid form, solid, nearly orbicular, slightly convex, suffused with yellow or pink, strongest on the interior PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA of the shell, or plain white; beaks subcentral small, prosogyrate, with a small, more or less excavated lunule usually almost confined to the right valve; sculpture chiefly of fine, low, rather sharp, concentric threads with occasional sulci, due to resting stages, near the margin in senile specimens; radial sculpture comprising more or less microscopic stria- tions and a broad shallow flexuosity of the posterior dorsal area, which is often obsolete; dorsal areas inconspicuous; hinge and muscular impressions normal, basal margins very minutely crenulate. Alt. 23.5, lat. 23.5, diam. 10.5 mm.” Holotype.—Presumably in the collections of the National Museum of Natural History, but not designated by Dall nor listed by Boss and others (1968). Type locality.—La Paz, Baja California Sur. Holocene. Supplementary description—“The amount of excavation of the lunule in P. lamprus varies in individuals, and between the two valves. It seems to be relatively greater in the young“**” (Dall, 1901, p. 827) “The double laterals of the left valve are obscure in most specimens of this species but show up well occasionally." (Durham, 1950, p. 76) Comparison—“Lucina californica Conrad differs from L. lampra Dall in the position of the lunule, which is wholly in the right valve, and the division of the valves which follows the lunular margin distinguishes this species from all other Western American representatives of the genus. “Lucina lampra is the most nearly circular member of the closely related series including L. prolongata and L. lingualis. The three species are distinguished from each other by the ratio between altitude and longitude; L. lampra is longer than high; in L. lingualis the two dimen- sions are about equal; while L. prolongata is higher than long, and pronouncedly oblique. All three species are without radial sculpture.” (Jordan, 1936, p. 130) “The middle cardinal of right valve is more nearly vertical, and the anterior laterals are closer to the beak than in L. lingualis. (Durham, 1950, p. 76) Geographic range—Living: Baja California Norte to Mexico; fossil: Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in Baja Califomia.—Pliocene: Marquer Formation (Durham, 1950); Pleistocene: unnamed strata on Islas Coronados (Durham, 1950; Emerson and Hertlein, 1964), Isla Monserrate (Emerson and Hertlein, 1964), and Puente El Pulpito, Baja California Sur (Hertlein, 1957) Callucina (Callucina) lingualis (Carpenter) Plate 3, figures 17, 19 Lucina lingualis Carpenter, 1864, p. 313. Jordan, 1936, p. 131. Palmer, 1945, p. 99. Lucina (Mgrtea) lingualis Carpenter. Grant and Gale, 1931, p. 286. Phacoides (Cavilucina) lingualis Carpenter. Dall, 1901, p. 811, 827, pl. 39, fig. 7. Lucina (Callucina) lingualis Carpenter. Chavan, 1937, p. 254. Palmer, 1963, p. 304—305, pl. 59, figs. 1—5. Keen, 1971, p. 120, fig. 269. Lucina(Cardiolucina) lingualis Carpenter. Durham, 1950, p. 76, pl. 18, figs. 3, 10. Lucina (Cavilinga) lingualis Carpenter. Hertlein and Strong, 1946, p. 113. Olsson, 1961, p. 211, pl. 31, fig. 11. Original description—“L. testa solida, linguiformi, valde prolongata; plerumque aurantiacocarnea, intus intensiore; lirulis concentricis botusis crebre ornata; marginibus undique excurvatis; lunula minima, altissime excavata; parte postica obscure biang‘ulata, seu subrotundata', umbonibus anticis, incurvatis; ligamento subinterno, lamina valida; dent. card. et lat. normalibus, validis; cicatr. adduct. posticis subovalibus, anticis satis elongatis; linea pallii lata, rugosa; margine interno crenulato. Long. .88, lat. .92, alt. .4 poll. y I 7 ‘ l “Variat t. minus firolongata. ‘ilariat quoque t. pallide viridi, seu pallide carnea, seu alba.” l l Syntypes.—USN 15898; Rédpath Museum 114. Type locality—Cabo San deas, Baja California Sur. Holocene. Supplementary description.1—“Shell small (height about 13 mm.), tongue-shaped, higher than long, solid, white. Dorsal areas obscure, the posterior one somewhat stron er and flattened. The small beaks are subcentral, pointed forward. urface scuptured with fine concentric threads, often irre‘ arly intdrrupted by deep, resting sulci. Ventral margins crenulated.” (Olsson 1961, p. 211) Comparison—“The height and length of this species [L. (C.) lingualis] are almost the samé“ * *so that it is higher for its length than L. lampra.” (Keen, 1971, p. 120) Geographic range—Living: i3ahia Magdalena, Baja California Sur, to Mexico; fossil: Baja Californi Sur. Geologic range.+Pliocene t Holocene. Occurrence in Baja California Sun—Pliocene: Marquer Formation (Durham, 1950); Pleistocene) unnamed strata at Bahia Santa Inez (Durham, 1950). 1 ‘ 3 l Genus coriAKIA Scopoli, 1777 Medium-sized to large, lenticular, compressed, slightly inequilateral; concentric or rad al sculpture predominant; small deep lunule in right valve; ligament broadly sun en. Anterior laterals and cardinals well marked, posterior laterals obsolete or small; shell margin smooth. Geographic range—Europe, America, Asia, Australia, Pacific. Geologic range.,—Jurassic o Holocene. ‘ l l , Subgenus CODAKIA l Generally largel, sculpture lieticulate; lunule small, very asymmetrical, depressed; ligam‘entary groove broad. Posterior laterals obsolete. Geologic range—Paleocen‘b to Holocene (table 1). ‘ l Codaycia (Cod ia) distinguenda (Tryon) Plate 1, figinre 14; plate 2, figures 1—3 l Lucina (Codakia) distingueinda Tryon, 1872, p. 130, pl. 6, fig. 3. Codakia distin enda (Trydn). Grant and Gale, 1931, p. 283. Hertlein and Strong,‘1946, p. 1 7—118. Codakia (Codakia) distinguenda (Tryon). Durham, 1950, p. 74, pl. 18, figs. 2, 15. omen, 1961, p. 217, pl. 29, fig. 3; pl. 33, figs. 4a, 4b. Original descniption.—“:iwell orbicular, depressed, disk-like, covered with flattened radiating ri ges which are crossed by numerous close- set, raised concentric stria . White with a faint tinge of pink: interior with a broad marginal ban} of deep pink.” Syntype.—ANSP 54787 3 valves). Type locality.,‘—Golfo de California. Holocene. Supplementary descript on.—“Shell large, circular or orbicular, generally heavy and thick. i'éculpture formed by small, finely beaded or cancellated, radial riblets, few of the riblets are occasionally larger and separated by deeper r dial grooves giving the effect of wide rays. Hinge plate milch wider or higher than in the West Indian or Carib- bean C. orbicularis***” ( lsson, 1961, p. 217) Comparisonq—Codakia istinguenda is distinguished from Codakia tigrina Linné by its flattened form and broader and more depressed ribs (Tryon, 1672, p. 130)‘ Comments.—fl‘he speci en figured from the Pliocene Marquer Formation haslribs that arle much wider at the anterior dorsal margin. Geographic ‘anger-Livigig: Baja California Norte to Panama; fossil: southern California to Ba a California Sur. Geologic range—Miocer‘ie to Holocene. l l l 1 l l 1 il‘ERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D11 Occurrence in the Californias.—Miocene or Pliocene: Imperial Formation (G D. Hanna, 1926); Pliocene: Marquer Formation (Durham, 1950); Pleistocene: unnamed strata at Coronados Island (Hertlein, 1931), Bahia Santa Inez and Isla Carmen (Hertlein, 1957); and of Baja California Sur (Durham, 1950). Subgenus EPILUCINA Dall, 1901 Medium-sized, with concentric sculpture only; lunule rather large, asymmetrical; ligamentary groove of moderate extent. Posterior laterals small. The shell of Epilucina differs from that of Callucina by having the lunule situated entirely in the right valve instead of partly in the left one, smooth inner margins, and strongly projecting laterals (which on Callucina are very slightly developed). Geographic range—Fossil: Europe and North America; living: California. Geologic range—Jurassic to Holocene (table 1). Habitat—Intertidal to 145 m (Hertlein and Grant, 1972, p. 247). Codakia (Epilucina) californica (Conrad) Plate 1, figures 16, 17 L[ucina] californica Conrad, 1837, p. 255, pl. 20, fig. 1. Phacoides (Epilucina) californicus Conrad. Dall, 1901, p. 813. T.S. Oldroyd, 1924, p. 5. Callucina californica (Conrad). Dall, 1921, p. 35. Lucina (Myrtea) californica Conrad. Grant and Gale, 1931, p. 285—286, pl. 14, figs. 15a, 15b, 21a, 21b. Codakia (Epillucina) californica Conrad. Abbott, 1974, p. 460, fig. 5299. Lucina (Epilucina) californica Conrad. Hertlein and Grant, 197 2, p. 247—248, pl. 46, figs. 11, 16. Original description—“Shell lenticular, with coarse concentric striae; posterior extremity direct; lunule small, elliptical, impressed, trans- versely striated, prominent in the right valve, and fitting into a cor- responding depression in the left; cardinal and lateral teeth prominent. “The lunule in the shell is remarkable for forming a distinct tooth, and the shell is destitute of a fold.” Holotype.—Unknown (Hertlein and Grant, 1972). Type locality—Inhabits muddy marshes near Sta. Diego. San Diego County, Calif. Holocene. Supplementary description—“The hinge of californica has a promi- nent right anterior cardinal tooth, between which and the beak the elongate, rather deep-set pseudo-lunule projects, fitting into a corre- sponding space in the left valve anterior to its beak. The anterior and posterior radial plications are obscure or entirely wanting.” (Grant and Gale, 1931, p. 286) “Shell to about 35 mm in diameter, rounded in outline, with beaks centrally placed on dorsal margin; external ligament in a deep pit; outer surfaces of valves sculptured with fine concentric lines and a low ridge extending posteriorly from beaks****” (Haderlie and Abbott, 1980) Comparison—“The shell of this species is easily separable from that of other species of Lucina occurring in Pliocene beds in California by the complete lack of any depressed area either posteriorly or anteriorly, concentric sculpture only, and in the character of the lunule which lies entirely in the right valve. “Lucina (Myrtea) nipponica Nomura and Hatai from beds of middle Miocene age in Japan***was said to differ in the smaller size, finer sculpture, and in the somewhat different outline.” (Hertlein and Grant, 1972, p. 247) Geographic range—Living: Northern California to Baja California Sur; fossil: middle California to Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in the Californiaa—Miocene: Santa Margarita Formation (Preston, 1931); Miocene and Pliocene: Towsley Formation (Kern, 1973); D12 Pliocene: Niguel (J .G. Vedder, written commun., 1978) and Potato Harbor (Weaver and Meyers, 1969) and San Diego (Hertlein and Grant, 1972) Formations; unnamed strata on Isla Cedros, Baja California Norte (Jordan and Hertlein, 1926) and on Deadmans Island, San Pedro Harbor, Calif. (Arnold, 1906); Pliocene and Pleistocene: Fernando (Arnold, 1907a; Eldridge and Arnold, 1907; Moody, 1916; Soper and Grant, 1932), San Pedro (Arnold, 1903; T.S. Oldroyd, 1924), and Santa Barbara (Arnold, 1903; Dibblee, 1966) Formations and unnamed strata on Santa Cruz Island (Orr, 1960); Pleistocene: Timms Point Silt Member, San Pedro Formation (Arnold, 1906; Clark, 1931) and unnamed Pleistocene strata on Anacapa Island (Valentine and others, 1968), at Baldwin Hills (W illett, 1937b), Capistrano Beach (W illett, 1938), Cayucos (Valentine, 1958), high terraces at Palos Verdes Hills (Marincovich, 1976), on San Clemente Island (Lipps, 1967), San Nicolas Island (V edder and Norris, 1963), Santa Barbara Island (Lipps and others, 1968), Santa Cruz Island (Orr, 1960), in southern California (Valentine, 1956, 1960a; Kanakoff and Emerson, 1959; Emerson and others, 1981), at Bahia San Quintin (Jordan, 1926), Baja California Norte (Valentine, 1957; Hertlein and Grant, 1972), and Bahia Tertola, Baja California Sur (Emerson and others, 1981). Habitat—Common in rocky rubble and sand, low intertidal zone to offshore depths of 80 m (Haderlie and Abbott, 1980, p. 370); 30 to 75 m (Bernard, 1983). Genus CTENA Miirch, 1861 Ovate to elliptical, compressed; beaks pointed; sculpture regularly reticulated; lunule concave. Cardinals short or thin. Geographic range—Europe, North America, Pacific and Indian Oceans, West Africa, Australia. Geologic range—Eocene to Holocene (table 1). H abitat.—Eastern Pacific species are found intertidally to a depth of 120 m from Baja California Norte to Ecuador. Subgenus CTENA Moderately convex, somewhat inequilateral, with well-developed radial ribs and lunule. Cardinals short and normally developed, laterals strong, inner shell margin finely denticulated. Geographic range—Europe, North America, Pacific and Indian Oceans, West Africa. Ctena (Ctena) mexicana (Dall) Plate 2, figures 4-6, 11 Lucina pectinata Carpenter, 1857, p. 98 [not of GB. Adams, 1852]. Coolakia (Jagonia) mericana Dall, 1901, p. 801, 822, pl. 40, fig. 6. Durham, 1950, p. 74—75, pl. 18, figs. 7, 14. Codakia mexicana Dall. Jordan, 1936, p. 129. Ctena mexicana (Dall, 1901). Keen, 1968, p. 396, pl. 56, fig. 21. Keen, 1971, p. 125, fig. 284. Original description—“One of Reeve's figures in the Iconica (fig. 33) appears to represent this species, which is very similar to the West Indian C [odakia] orbicalata Montagu. I find, however, on careful examination that in the west coast shell the lunule is narrower, longer, and less deeply impressed than in C. orbic’alata, the shell is more delicate, thinner, and more flattened toward the lower margins, the sculpture is more regular and the concentric threads less crowded, so that while the difference is not great the effect in C. mexicana is much more elegant; toward the ends it has the radials stouter and with wider interspaces, and with the sculpture on the dorsal areas less distinct from that on the disk than it is in the West Indian form. It is most commonly labeled Lucina bella Conrad, in collections, and by Carpenter was named L. pectinata, though it is not the pectinala of Gmelin or CE. Adams. A full-grown specimen measures: alt. 21, lon. 23, diam. 10.0 mm.” Holotype.—BM(NH) Tablet 470 (Keen, 1968). PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Type locality—Mazatlan, Mexico. Holocene. Supplementary description.—“recognizable by its fine and numerous radial ribs, which are evenly distributed over the entire white shell.” (Keen, 1971, p. 125) Comparison.—“A much smaller and more elongate shell than Codakia distenguenda (Tryon), the big, circular species of tropical Western America“ *, the adult not reaching quite an inch in length. The radial sculpture is well developed, not subobsolete as in C. chiquita Dall.” (Jordan, 1936, p. 129) Comments.—Ctena (Ctena) chiquita (D311) is figured for comparison (pl. 2, figs. 7—10). Geographic range—Living: Golfo de California to Ecuador; fossil: Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in Baja California Sun—Miocene: Comondu Formation (Durham, 1950) Pliocene: Marquer Formation (Durham, 1950); Pleisto- cene: unnamed sediments on Islas Coronados, at Bahia Santa Inez, and Concepcion (Durham, 1950). Habitat—Found intertidally to depths of 80 m (Keen, 1971, p. 125). Genus HERE Gabb, 1866 Medium—sized to small, rounded, subglobular with concentric ribs tend- ing to vanish; lunule deeply excavated, covering part of hinge; well developed concentric sculpture; internal shell margin with minute denticles. Geographic range—Western Europe, western North America, North Africa. Geologic range—Paleocene to Holocene (table 1). Subgenus HERE Concentric ribs fine but well marked; lunule rather broadly rounded, obliterating only the anterior cardinal, posterior ones well marked; anterior laterals minute; internal shell margin finely crenulated. Illesca Olsson, described as a subgenus of Here, differs in that the lunule is entirely immersed in the hinge-plate and in both valves seems to have completely effaced the anterior cardinal. Geographic range—Western Europe, western North America. Geologic range—Eocene to Holocene. Here (Here) hannai (Clark) Plate 2, figures 12-15 Lucina (Here) hannai Clark, 1938, p. 696, pl. 2, figs. 3—5. Original description—“Shell suborbicular in outline, moderately inflated, with rather strongly inturned, acute but only moderately prom- inent beaks which are anterior to the medium line; length about equal to the height; general surface smooth except for moderately heavy irregular lines of growth; a broad shallow groove parallel and a little anterior to the posterior dorsal edge; below and anterior to the beaks is a strong, fairly deep excavation which infringes on the hinge plate, forming the lunule so characteristic of this subgenus. Hinge with two small cardinals on the left valve separated from the two small claspers of the anterior lateral by the lunular excavation already referred to; a small but well-developed lateral posterior to the ligamental groove of the right valve with corresponding clasper on the left; on the right valve, one bifid cardinal, the upper part of this tooth covered by a callus growth; a small anterior lateral. Dimensions of holotype, a left valve, 30841, length 14 mm., height 14 mm.; paratype 30842, length 13.6 mm., height 12.8 mm. Named in honor of G D. Hanna.” Holotype.—UCMP 30841. Type locality.—UC A—1297. Solano County, Calif. Markley Forma— tion, Eocene. A4 1 ‘4 vfi“ 4 i TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE Comparison. —Here hannai idiffers from Here excavata “considerably in outline; it is not as high in p oportion to the length and is more nearly circular; the lunular excavation on the hinge plate is narrower, the laterals have a different orie tation on the hinge plate and the hinge plate itself is not as broad.”i(Clark, 1938, p. 696) Geographic range—Middle California. Geologic range—Eocene. Occurrence in California.— ocene: Markley Formation (Clark, 1938; Weaver, 1949). F Here (Here) efiingfri (Weaver and Kleinpell) Plate 2, figur 16; Plate 3, figures 1, 2 Lucina (Here) eflingeri Weav r and Kleinpell, 1963, p. 201, pl. 33, fig. 9. Original description—“Sh ll small, very inflated, nearly equilateral; equivalved; anterior dorsal s ope very slightly concaved; beaks small, inconspicuous; anterior, post rior, and ventral margins form one con- tinuous and uniform curve. eakly developed concentric lines decorate the shell. Lunule and escutc eon obsolete.” Holotype.—CAS/SU 9285. Type locality—UC B—6955. Santa Barbara County, Calif. Sacate and Gaviota Formations undiffejentiated. Eocene and Oligocene. Comparison—“This speci s is similar to Lucina dalli (Dickerson) of Weaver (1942, p. 146), but is uch more inflated and lacks the posterior truncation.” (Weaver and K einpell, 1963, p. 201) Geographic range—South rn California. Geologic range—Eocene a d Oligocene. Occurrence in California. Eocene: Sacate Formation (Weaver and Kleinpell, 1963); Eocene and ligocene: Gaviota Formation (Weaver and Kleinpell, 1963). ‘ Here (HereF excavata (Carpenter) Plat} 3, figures 5—14 Lucina excavata Carpenter, 1857, p. 98. Lucina (Here) excavata Cardenter. Stewart, 1930, p. 181—182, pl. 15, fig. 3; pl. 17, fig. 5. Gra t and Gale, 1931, p. 290—291, pl. 14, figs. 2, 5, 10. Palmer, 1958, p. 6. Keen, 1968, p. 396, pl. 56, fig. 23. Keen, 1971, p. 121, fig. 271. Hertlein and Grant, 1972, p. 244, pl. 46, figs. 1—3. Here (Here) excavata (Carpen er). Chavan in Moore, 1969, p. N496, figs. E3, 1a, 1b. Here excavata (Carpenter). ddicott, 1973, p. 27—28. pl. 3, figs. 6, 8, 9. Lucina (Here) richthofeni G bb, 1866, p. 29, pl. 8, figs. 49, 49a, 49b. Phacoides richthofeni (Gabb). Arnold, 1907a, p. 543, pl. 45, fig. 4. Clark, 1915, pl. 62, fig. 2. Phacoides (Here) richthofeni Gabb. Loel and Corey, 1932, p. 210, pl. 36, fig. 4. Lucina richthofeni Gabb. Hanna and Hertlein, 1943, fig. 63—13. Original description—“L. t. alba, tenui, complanata; suborbiculari; striis concentricis exillimis; postice angulata, umbonibus incurvatis; lunula parva, alte excavata, dent. card et. lat. haud magnis; impres- sionibus muscularibus postisa ovali, antica valde.elongata; margine integro.” (excavata) “Shell subglobose, nearly quilateral; beaks small, inclined forwards; margins regularly rounded;1a more or less distinctly marked groove passes from the beaks to t e posterior margin. Surface marked by numerous, more or less regular, distinct, rounded ribs.” (richthofeni) Syntypes.—BM(NH) tablet 468. “Tablet 468 contains the two valves and a fragment to shew [sho ] the external surface.” (Carpenter, 1857, p. 98) “Originally 2 syntypes ***Only a single valve remains. It is worn but recognizable and has bejnpcorrectly identified by modern workers.” (Keen, 1968, p. 396). Lectot e of L. richthofeni ANSP 4492 (Stewart, 1930)(pL 3,figs.11—13) ‘ D13 Type locality—Mazatlan, Mexico. Holocene. Of L. richthofeni San Fer- nando Valley, Los Angeles County, Calif. Pico Formation, Pliocene and Pleistocene. Supplementary description—“Distinguished by the very small, most deeply cut lunule, bounded on one side by the cardinal, on the other by the anterior lateral tooth. A larger lunular portion is marked out by a line, and the posterior margin is slightly bi-angulatedf’ (Carpenter, 1857, p. 98) “Lucina excavata Carpenter is readily recognized by its globose, in— flated shape, concentric ridges, and deeply depressed pseudo-lunule. With the two valves together, as they often are, even in fossils, it resembles a nut.” (Grant and Gale, 1931, p. 290) “Shell relatively small (length 25 mm. or less), rounded, globose, nut- shaped. Anterior dorsal area more strongly defined than the posterior, enclosing the deep, penetrating lunule. Surface marked with strong, concentric ridges, and smaller striae.” (Olsson, 1961, p. 208) “The globosity of the various valves varies as does the spacing of the ribbing which may be closely or widely separated.” (Hertlein and Grant, 1972,p.244) Comments.—The holotype of L. richthofeni is a small imperfectly preserved left valve and the hinge is not exposed (pl. 3, figs. 11—13). See also pl. 3, fig. 14. Geographic range—Living: southern California to Mexico; fossil: middle California to Baja California Sur. Geologic range—Eocene to Holocene. Occurrence in the Californias.—Eocene: San Emigdio Formation (Wagner and Schilling, 1923, DeLise, 1967); Oligocene: So-called Phacoides Sand Member (Addicott, 1972) and Wygal Sandstone Member (Addicott, 1973), Temblor Formation; Oligocene and Miocene: Temblor (Smith, 1912; Woodford, 1925; Heikkila and MacLeod, 1951) and Vaqueros (Arnold, 1906; Smith, 1912; Loel and Corey, 1932) Forma- tions; Miocene: Castaic Formation (Stanton, 1966), Cierbo Sandstone, San Pablo Group (Clark, 1915; Hall, 1960), McLure Shale Member (Adegoke, 1967), Monterey Formation; Monterey Formation (Smith, 1912; Stewart, 1946), Neroly Sandstone, San Pablo Group (Clark, 1915; Weaver. 1949; Hall, 1960), Olcese Sand (Addicott, 1965), Pancho Rico (Durham, 1965; Durham and Addicott, 1965), Puente (Eldridge and Arnold, 1907), Santa Margarita (Clark, 1916; Nomland, 1917b; Preston, 1931; Addicott and Vedder, 1963), Tierra Redondo (Durham, 1968), and Topanga (Arnold, 1907b; Kew, 1924; Hoots, 1931; Woodring, 1931; Soper, 1938; Takeo Susuki, written commun., 1981) Formations; Miocene and Pliocene: Etchegoin (Nomland, 1917a) and Towsley (Winterer and Durham, 1962; Kern, 1973) Formations; Pliocene: Niguel (J .G. Vedder, written commun, 1978), lower part of Fernando (Oakeshott, 1958), and San Diego (Hertlein and Grant, 1972) Formations; Pliocene and Pleistocene: Fernando (Eldridge and Arnold, 1907; English, 1914; Durham and Yerkes, 1964) and Pico (Grant and Gale, 1931 ; Winterer and Durham, 1962; Addicott and Vedder, 1963) Formations; Pleistocene: unnamed strata in southern California (Valentine, 1956; Kanakoff and Emerson, 1959; Kern and others, 1971), in Baja California (Valentine, 1957), at Bahia San Quintin (Jordan, 1926), and Bahia Tertola (Emer- son, 1980). Habitat.—5 to 110 m (Bernard, 1983). Genus LINGA de Gregorio, 1884 Medium—sized, rounded, tumid; concentric ribbing more or less lamel- lose; lunule sunken, short, cordiform. Hinge teeth strong, short; anterior scars moderately short; shell margin internally denticulated. Geographic range—Europe, America, Africa, Asia, Australia. Geologic range.—Pale0cene(?); Eocene to Holocene (table 1). Subgenus PLEUROLUCINA Dall, 1901 Smaller than Linga s.s., oblong, more or less trigonal to quadrate, with sharp dorsal angulation; radial sculpture of low folds, stronger at ends of shell; lunule not immersed; inner margin crenate. D14 Geographic range—North and Central America. Geologic range. —Oligocene to Holocene (table 1). H abitat.—A warm-water genus found at depths of intertidal to 110 In in the eastern Pacific. Linga (Pleurolucina) cancellaris (Philippi) Plate 4, figures 20, 24—26 Lucina cancellaris Philippi, 1846, p. 21. Carpenter, 1857, p. 99. Jordan, 1936, p. 130. Phacoides (Bellucina) cancellaris (Philippi). Dall, 1901, p. 814, pl. 39, fig. 11. Lucina (Bellucina) cancellaris Philippi. Grant and Gale, 1931, p. 290. Hertlein and Strong, 1946, p. 112. Durham, 1950, p. 75, pl. 18, figs. 8, 13. Lucina (Pleurolucina) cancellaris Philippi. Keen, 1971, p. 121, fig. 276. Original description—“L. testa parva, suborbiculari, subaequilatera, tumida, alba; lineis elevatis radiantibus transversisque cancellata; lunula excavata; apicibus acutis uncinatis; margine intus crenato. Altit. 2’”; long. 2’”; crass/ 11/2’” “Ich zahle gegen 26 vom Wirbel ausstrahlende, erhabene Linien; die aussersten sind wie gewohnlich kleiner und undeutlicher, aber auch die mittleren sind schmaler und dichter gestellt, als die angranzended. Die Gestalt ist fast ganz wie bei L. commutata Ph. (welches die achte Tellina divaricata L. ist). Mit L. pecten), squamosa, reticulata (Tellina) Poli kann diese Art nicht verwechselt werden; ihre stark Wolbung, -fast gelichseitige Form, und die Sculptur unterscheiden sie sogleich.” Holotype.—Location unknown. Type locality—Mazatlan, Mexico. Holocene. Supplementary description—“Shell, when extremely young, smooth at the umbo, then with stout concentric ridges, then with 8 or 10 very strong radiating rounded ribs crossing them. These branch out into other narrower ones, till there are about 26, strongly cancellated, and leaving deep pits between. Lunule small, deep: posterior ligamental portion flat- tened, separated by an indistinct keel. Interior margin deeply crenated; muscular scars (anterior elongated, irregular) rather distant from margin; lateral and cardinal teeth strong. The smallest specimen is .03 across. The largest, long. .15, lat. .14, alt. .09.” (Carpenter, 1857, p. 99) “The number of radiating ribs, and their intensity, varies in this species, as secondary and tertiary riblets are often interpolated that soon equal the primary ones in strength.” (Jordan, 1936, p. 130) “The variation in the ribs is great. Some specimens have as few as 8 broad heavy ribs; others, by intercalation of secondaries and bifurca- tion of the primary radial ribs, may have as many as 20 medium-sized ribs.” (Durham, 1950, p. 75) “Shell small, obliquely rounded, solid, sculptured with 10 to 12, strong, radial ribs, the ribs and interspaces cancellated by evenly spaced, raised concentrics which show especially strong in the deeply grooved inter- spaces as coarse cross threads, enclosing squarish pits between them. The typical form has the radial interspaces simple but in some shells, the interspaces are wider and have two or more fine, interstitial threads. The posterior-dorsal area is well defined, wide, and sculptured with two strongly scabrous riblets. Internally, the ventral margin is strongly fluted by the ribs and in addition finely crenulated.” (Olsson, 1961, p. 212) “A small shell***with its ribs intersected by overriding concentric threads. Large specimens are as much as 6 mm high.” (Keen, 1971, p. 121) Commuts.—Durham cites the geologic range of L. (B.) cancellaris as Pleistocene to Holocene (Durham, 1950, p. 75). The locality given for the specimen he figures is UC 3670, which is given as upper Pliocene on the fauna] chart opposite page 6 and as “Upper Pliocene, Puerto Balandra, Carmen Island. From sands at left end of outcrop and below PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA base of coral reef (10c. 3534).” Locality UC 3534, cited as equivalent to UC 3670, is also called Pliocene in age. Geographic range—Living: Baja California Norte to Panama; fossil: Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in Baja California Sun—Miocene: Comondu Formation (Durham, 1950); Pleistocene: Unnamed sediments at Bahia Magdalena and Santa Inez (Durham, 1950). Habitat—At depths of 5 to 70 m (Bernard, 1983). Genus PARVILUCINA Dall, 1901 Rather small, rounded, inflated, often inequilateral; with fine concen- tric sculpture and small radial striae weakening medially and generally forming a weakly or finely cancellate pattern. Ventral margin crenulate. Callilucinella Chavan differs from Par'uilucina in the larger size, irregular concentric sculpture, very fine crenulations on the margin, and longer lunule. The hinge also differs in the presence of a lateral lamella and in the elongated cardinal teeth, especially the posterior ones. Geographic range—Europe, Africa, North America, Australia. Geologic range—Cretaceous to Holocene (table 2). Habitat—Intertidal to 525 m (Hertlein and Grant, 1972, p. 248). Inter- tidal to 1025 m (Bernard, 1983). Subgenus PARVILUCINA Sculpture finely reticulate; ligament marginal. Internal shell margin very finely crenulated. Parvilucina (Parvilucina) tenuisculpta tenuisculpta (Carpenter) Plate 4, figure 12 Lucina tenuisculpta Carpenter, 1864b, p. 602, 611, 642. Carpenter, 1865, p. 57. Arnold, 1903, p. 133. Phacoides(Par1/ilucina) tenuisculptus Carpenter. Dall, 1901, p. 828, pl. 40, fig. 5. Phacoides tenuisculpta Carpenter. Clark, 1915, p. 419, pl. 62, fig. 3. Lucina (Myrtea) tenuisculpta Carpenter. Grant and Gale, 1931, p. 288. Lucina (Parvilucina) tenuisculpta (Carpenter). Palmer, 1958, p. 86—87, pl. 8, figs. 8—12. Original description—“Two living specimens of which one had the surface disintegrated.” (Carpenter, 1864b, p. 602) Holotype.—USNM 5244. Type locality—Vancouver Island, British Columbia. Holocene. Comparison—“Lucina tenuisculpta, n.s. Like Mazatlantica, Cat. 144, more convex, with finer sculpture. 4 fm. living, Cp. The island var. is intermediate. 120 fm. dead. Cp.” (Carpenter, 1864b, p. 642) Supplementary description.—“L.[ucina] t. ‘L. Mazatlanicae’ forma simili; sed magis convexa sculptura multo tenuiore; epidemide olivaceo- cinerea inducta; t. juniore laevi; postea, rugis incrementi concentricis, plus minusve conspicuis, distanibus, irregularibus; costulis radiantibus subobsoletis, latis, crebrioribus, antice et postice evanidis; area posica vix subquadrata, haud definita: intus, dentibus cardinalibus et lateralibus normalibus, satis extantibus; ligamento externo, elongata; circatrice antica normaliter prolongata; margine crenulato. Long. .23, lat. .21, alt. .13,” (Carpenter, 1865, p. 57) Comments—The specimen from the Miocene San Pablo Group iden- tified by Clark (1915, p. 419, pl. 62, fig. 3) is rounder in outline than the holotype of Parvilucina (P.) tenuisculpta tenuisculpta figured by Palmer (1958, pl. 8, figs. 8—12). The hinge is not exposed. __¢ i TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE l Geographic range—Livingi: Alaska to Baja California Sur; fossil: middle and southern Califorilia. Geologic range—Miocene tlo Holocene. Occurrence in California—lMiocene: Cierbo and Neroly Sandstones, San Pablo Group (Clark, 1915; Weaver, 1949; Hall, 1958) and San Pablo Formation (Clark, 1915); Pli cene: Upper part of the Capistrano For- mation (Kern and Wicander, 974) and Niguel Formation (J .G. Vedder, written commun., 1978) and unnamed sediments at Potrero Canyon, Santa Monica Mountains ( oots, 1931); Pliocene and Pleistocene: Fernando (Moody, 1916; Sop rand Grant, 1972; Zinsmeister, 1970) and San Pedro (Arnold, 1903) F0 mations; Pleistocene: Anchor Silt (Rodda, 1957), Timms Point Silt Me ber, San Pedro Formation (Clark, 1931), and unnamed strata in the Eoleta area (Upson, 1951), at San Nicolas Island (Vedder and Norris, 1963), Pacific Palisades (Valentine, 1956), and Spanish Bight, San Diego (Arnold, 1903). Habitat.—5 to 275 m (Bernard, 1983). Most abundant in areas of organic enrichment (Jones and Thompson, 1984). Parvilucina (Parvilu ina) tenuisculpta intensa (Dall) Plate 4,‘figures 17, 19, 21, 22 Liwina tenuisculpta Carpenter. Dall, 1874, p. 297. Not Lucina tenni- sculpta Carpenter, 1864. Phacoides (Parvilucina) int nsus Dall, 1903b, p. 1385, pl. 50, fig. 8. Lucina (Parcilncina) int sus (Dall). Hertlein and Grant, 1972, p. 248—249, pl. 46, figs. 6 7, 17, 22. Original description.—” hell small, resembling P.[hacoides] tenni- scnlptus Cpr., but with the oncentric sculpture much sharper though very fine, the radials feeble, ‘ he lunule large, lanceolate, and impressed, the beaks small and promi ent, the hinge very delicate, the posterior dorsal area with a wide, sh llow sulcus, and the inner margins rather coarsely crenulate. Alt. 4. mm, long. 5.0 mm, diam. 3.0 mm.” Sgntypes.—USNM 135041. Three syntypes; largest is 5.4 mm long, 4.8 mm high. 1 Type locality.—Pli0cene of San Diego, Calif, from a depth of 160 ft. [50 m] below the surface inlthe city park well. San Diego County. San Diego Formation, Pliocenel. Comparison—The consilstently smaller size, larger lunule, and stronger concentric sculpture separate Parvilucina t. intensa from P. t. tenuiscnlpta (Hertlein anlerant, 1972, p. 249). “Lucina (Par'uilucina) a pronimata Dall described from the Gulf of California bears some simi arity to L. tenuisculpta intensa, but it has much stronger radial scul ture.” (Hertlein and Grant, 1972, p. 249) Geographic range—Sou hern California. Geologic range.—Pliocen and Pleistocene. Occurrence in California‘rPliocene: San Diego Formation (Hertlein and Grant, 1972); Pliocepe and Pleistocene: Fernando Formation (Arnold, 1907a). ‘ l l Parvilucina (Pdrvilucina) approximata (Dall) Plate 4, figures 7, 8 l Phacoides (Parvilucina) approximatus Dall, 1901, p. 813, 828, pl. 39, fig. 4. l Phxwoides approximatus Dal]. Jordan, 1924, p. 148. Jordan, 1926, p. 244. Lucina (Myrtea) tennisculpta Carpenter var. approximata (Dall). Grant and Gale, 1931, p. 282, pl. 14, figs. 8a, 8b. Lucina approximala (Dali). Jordan, 1936, p. 129—130. Lucina (Parvilucina) applroximata Dall. Hertlein and Strong, 1946, p. 115—116. Durham, 1950, p. 77, pl. 18, figs. 12, 17. Olsson, 1961, p. 214, pl. 31, fig. 7. keen, 1971, p. 121, fig. 274. Original description.—‘ Shell small, tumid, nearly equilateral, white with a yellowish periostraclim; beaks high, full, with a rather emphatical- D15 ly depressed lanceolate lunule; sculpture of numerous fine, rounded, usually entire riblets separated by narrow sulci on the disk, but absent from the dorsal areas; concentric sculpture of low, feeble, distant, elevated lines which become feebly lamellose on the dorsal areas; hinge, especially the laterals, strong, normal; muscular scars as usual; basal margin conspicuously crenulate. Alt. 6.5, lon. 6.3, diam. 4.0 mm.” Holotype.—Not listed as in the USNM by Boss and others (1968). Type locality.—Golfo de California, in 26 fathoms, sand. Holocene. Supplementary description—“In the region south and east of Lower California this species, which is the Pacific analogue of P.[hacoides] crenella Dall, is very uniform, but toward the northern extreme of its range the radial riblets on the middle of the disk tend to become ob— solete, and then the concentric sculpture is more prominent. This variety does not change its size and never reaches more than one-third the size of the northern tenuisculptus, which had doubtless the same genetic origin, judging from the material I have examined.” (Ball, 1901, p. 829) “Shell small, rounded, nearly equilateral, the beaks high and full, curved over a deeply impressed, lanceolate lunule. The sculpture is pro- duced by small, simple, rounded riblets between narrow interspaces, both neatly cancellated by concentric threads; the radials are strongest on the ventral side of the disk but in some southern shells, they are replaced almost completely by close-set, raised, concentric threads on the umbonal portion. The posterior-dorsal area is flattened to excavated, sculptured by concentrics only which may enlarge to form two rows of scabrous threads. Size 4 to 7 mm.” (Olsson, 1961, p. 214) Comparison—“The specimens from San Quintin Bay practically unite this warmer-water type with the northern Lucina tenuisculpta Carpenter****Typically L. approximala does not exceed 6 mm. in length, is more delicate, and lacks the anterior right cardinal of L. tenuiscnlpta. The latter reaches some 15 mm in length.” (Jordan, 1936, p. 129) “The radial sculpture of variety approximata is more definitely developed than that on typical tenuisculpta, it being very faint or ob- solete on the latter form.” (Grant and Gale, 1931, p. 289) Geographic range—Living: middle California to Panama; fossil: southern California to Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in Baja California Sun—Pliocene: Comondu Formation (Durham, 1950) Pliocene and Pleistocene: Fernando (J .D. Mount, writ- ten commun., 1971) and Pico (Addicott, 1969) Formations; Pleistocene: unnamed sediments at Newport Bay, California (Kanakoff and Emer- son, 1959), Bahia Tértola (Emerson and others, 1981), Bahia Magdalena, Bahia San Quintin (Jordan, 1926), and Isla Margarita (Durham, 1950). Habitat.—Intertidally to depths of 1024 m (Keen, 1971); 1 to 1025 m (Bernard, 1983). Genus ANODONTIA Link, 1807 Rounded, tumid, slightly inequilatera]; sculpture of irregular growths and very fine radial striae; beaks prosogyrous; lunule ill-defined; liga- ment oblique, sunken. Hinge edentulous except for faint tuberculiform cardinal; shell margin internally smooth. Geographic range—Europe, Asia, North America, Pacific, Australia, Africa. Geologic range—Eocene to Holocene (table 2). Subgenus ANODONTIA Medium—sized to large, globose, rounded in front, slightly truncate posteriorly; surface with concentric and radial lines, lunule depressed; ligament sunken but inserted upon cardinal elongation. Geographic range—Europe, Asia, North America, Pacific Ocean, Australia. D16 Genus ANODONTIA? Subgenus ANODONTIA? Anodontia? (Anodontia?) inflata (Wagner and Schilling) Plate 1, figures 13, 15, 18 Phacoides (Callucina) inflata Wagner and Schilling, 1923, p. 254, pl. 45, figs. 3, 4. Original description—“Shell fairly large; subcircular; very strongly ventricose; equivalve; nearly equilateral; slightly longer than high; beaks slightly anterior to center; lunule distinct, small and deeply impressed; posterior dorsal edge long; slightly convex; ligamental groove long and distinct; anterior dorsal margin straight or slightly convex; there is a conspicuous depression which extends from the beaks to the anterior extremity; a faint depression extends to the posterior extremity; ex- tremities broadly truncate, ventral edge strongly arcuate; shell covered by heavy, irregularly spaced incremental lines and ribbed internally by a faint, irregular radial ribbing which crenulates the edge; hinge unknown. Dimensions: length, 66 mm.; height, 60.8 mm.; convexity, 43 mm.” Holotype.-—UCMP 11418. Type locality.—UC 3195. Kern County, Calif. San Emigdio Forma- tion, Eocene. Comments—Although poorly preserved with most of the shell miss- ing and the hinge not exposed, the rounded shape and very globose valves seem anodontid although the remaining shell has no fine concentric ridges or lines. Geographic distribution—Southern California. Geologic distribution—Eocene. Occurrence in California—Eocene: San Emigdio Formation (Wagner and Schilling, 1923; DeLise, 1967). Subfamily MYRTENIAE Genus MYRTEA Turton, 1822 Transversely elliptical to quadrangular, flattened; sculpture of con- centric, posteriorly elevated ribs with intercalated vermiculate radials in some; beaks pointed; lunule and escutcheon narrow and straight. Internal shell margin smooth. Geographic range—Europe, Australia, New Zealand, Asia, North America. Geologic range.—Cretaceous(?); Oligocene to Holocene (table 2). Subgenus MYRTEA Concentrically ribbed; ligament external. Teeth well developed, laterals of same length anteriorly and posteriorly. Myrtea (Myrtea) taflana (Dickerson) Plate 4, figures 13, 14 Phacoides (Myrtea) taflana Dickerson. 1916, p. 485, pl. 36, fig. 11. Ander- son and Hanna, 1925, p. 170. Original description—“Shell small, compact, trigonal; beak small, prominent, opisthodetic; concentric growth lies prominent, lamelliform. A marked posterior fold extends from the beak to the posterior end; posterior dorsal margin slightly convex; anterior dorsal margin slight- ly concave; base rounded. Area small and not distinctly set off. Pallial line simple, entire; two cardinal teeth in right valve, the posterior one being bifid; two cardinal teeth in left valve; a posterior lateral and an anterior lateral tooth are found in the right valve with corresponding sockets in the left valve.” PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Holotype.—UCMP 11789. Type locality.—UC 672. Fresno County, Calif. Cerros Shale Member, Lodo Formation, Paleocene. Supplemta’ry description—“Shell with prominent, strongly inturned prosogyrous beaks, below and anterior to which is a broad, fairly deep groove reaching the edge of the shell at a point which may be taken as the junction between the anterior dorsal edge and the anterior end; on the anterior margin just below the beak is the deep inset lunule which characterizes this genus; general surface sculptured by a series of heavy, rounded, subangulate lamellae on which are the finer incremental lines. Hinge of right valve“ * *with heavy deeply bifid cardinal, the upper end covered by the extension of the inner edge of the deep inset lunule; and anterior fairly prominent rounded lateral well in front of the lunule.” (Clark, 1938, p. 697) Geographic range—Middle California. Geologic range—Paleocene and Eocene. Occurrence in California—Paleocene: Cerros Shale Member, Lodo Formation (Dickerson, 1916); Eocene: Avenal Sandstone (V okes, 1939; Stewart, 1946), La J olla Formation (Vokes, 1939), and Muir Sandstone (Weaver, 1953). Genus LUCINOMA Ball, 1901 Shell usually large, lenticular, moderately convex; with well developed concentric lamellar sculpture; lunule lanceolate, long, not sunken or bent. Cardinal teeth developed with the inner pair usually bifid and the laterals obsolete or absent. Alucinoma Habe differs from Lucinoma in lacking cardinal teeth. Geographic range—Europe, North America, Pacific, Australia, Japan. Geologic range—Eocene to Holocene (table 2). H abitat.—Prefer cool water but also occur in tropical waters. At depths of 15 to 700 m in the Eastern Pacific. Lucinoma acutilineata (Conrad) Plate 4, figures 1—3, 6 Lucina acutilineata Conrad, 1849, p. 725, atlas pl. 18, figs. 2, 2a, 2b. Phacoides acutilineata Conrad. Arnold, 1909, p. 122, pl. 8, fig. 4. Dall, 1909, p. 116, pl. 12, fig. 6. Clark, 1925, p. 89. Phacoides (Lucinoma) acutilineatus (Conrad). Loel and Corey, 1932, p. 211, pl. 36, fig. 3. (Lucina) (Myrtea) aculilineata Conrad. Grant and Gale, 1931, p. 286, pl. 14, figs. 22a, 22b. Lueina (Lucinoma) acutilineata Conrad. Hanna and Hertlein, 1943, p. 174, fig. 64—16. Lucinoma acutilineata (Conrad). Stewart, 1946, pl. 17, fig. 9. Moore, 1963, p. 70—71, pl. 15, figs. 7—10, 12. Adegoke, 1969, p. 113. Addicott, 1973, p. 28, pl. 2, fig. 6, pl. 3, figs. 3, 7. Original description—“Suborbicular; ligament margin short, straight, and a little oblique; posterior margin somewhat truncate, widely, nearly direct; superoanterior margin truncate. Surface with concentric lamelli- form striae and intermediate fine lines; anteriorly with a slightly prom- inent fold. Basal margin orbiculate. This species is very nearly related to L. [ucina] contracta (Say), a recent shell of the Atlantic coast, and fossil in the Miocene of Virginia. It differs from Say’s species in being proportionally more elevated, and in having a much shorter ligament margin.” Lectotype.—USNM 3519 (Woodring, 1938). Type locality.—-Astoria, Clatsop County, Oreg. Astoria Formation, Miocene. Supplementary description—“The lectotype of L. acutilineata is double valved, and the shell is missing on the umbonal area of the left valve and on more than half of the right valve. This specimen is 37.3 mm long, 35.2 mm high, and 16.7 mm wide.” (Moore, 1963, p. 70). I 4* 4'4~,j4'—§—'—' l ' ‘— ‘ ‘ ‘WFV' “Lucinoma acutilineata is characterized by regularly spaced, sharp concentric lamellae. The inte spaces are packed with extremely fine con- centric threads. The spacing iif the primary lamellae is variable, as noted by Moore (1963). On a few pecimens, these ribs are spaced twice as far apart as on others, almo t as if alternate ribs had been omitted as the shell was being depositid.” (Addicott, 1973, p. 28). Comparison—Lucinmw cutilineata “is characterized by having a small, short and narrow lun 1e in contrast to the more elongate one in L. hannibali” (Weaver, 194}, p. 143). “Lucinoma acutilineata“ has a shorter more concave dorsal margin than L. hannibali. Variation‘ has been noted (Moore, 1963270) in the spacing of concentric lamell within single lots of the Holocene species Lucinama annulata (Reevefg850) and by Addicott (1976: 30) in* * *L. acutilineata, yet specimens f L. hannibali from the upper part of the Lincoln Creek Formation have concentric lamellae rather consistently less densely spaced***than the lamellae on L. acutilineata**** If L. hannibali and L. acutilineatai are distinct species, and I believe that they are, L. acutilirwata may have preferred somewhat shallower water (50 m or less) than L. hannibali d the two species coexisted at different depths.” (Moore, 1984, p. 2 ) “L. acutilineata is compar ble to the Recent species L. annulata, but L. acutilineata has a heavief hinge and, as pointed out by Stewart (in Tegland, 1933, p. 116), a sh rter posterior dorsal margin. In the right hinge plate of L. acutilineatlaHWhe anterior tooth is short and blunt, whereas on L. annulata it i7 thin and bladelike; the cardinal tooth also seems to be shorter on L. annulata. The left anterior tooth on L. acutilineata is heavier and hot as deeply incised as on L. annulata.” (Moore, 1963) Geographic range—Alasda to southern California. Geologic range.—Eocene td Pleistocene. [The Pliocene and Pleistocene records may actually be L cinema annulata (Reeve)]. Occurrence in Californ%—Eocene and Oligocene: San Lorenzo Formation (Arnold, 1906); ligocene: Agua Sandstone Bed of Santos Shale Member, Wygal San stone Member, (Addicott, 1973), so-called Phacoides Sand Member, TeEblor Formation (Addicott, 1972); Oligocene and Miocene: Santos Shal Member, Temblor Formation (Addicott, 1972), Temblor (Stewart, 19km; Adegoke, 1967), and Vaqueros (Arnold, 1906; Loel and Corey, 1932; Eaton and others, 1941; Moore, 1963) For- mations; Miocene: Buttonbdd Sandstone Member, Temblor (Addicott, 1972), Castaic (Stanton, 1966), Gould Shale Member (Addicott, 1972), Los Laureles Sandstone M mber (Bowen, 1966), and McLure Shale Member, Monterey (Adegdke, 1969; Weaver, 1949), and Monterey (Smith, 1912; Barbat and Johnson, 1934; Stewart, 1946, Weaver, 1949) Formations, Olcese Sand( dicott, 1965), Santa Margarita Formation (Arnold, 1906; Preston, 1351; Addicott and Vedder, 1963; Hall and Corbato, 1967), Sobrante andstone (Lutz, 1951; Moore, 1963), and Topanga Formation (Hoots, 1931; Woodring, 1931; Soper, 1938; Takeo Susuki, written commun., 1981); Miocene and Pliocene: Etchegoin (Arnold, 1909; Wilson, 1943) and Purisima (Arnold, 1906), Formations; Pliocene: lower part of Fe nando (Oakeshott, 1958) and San Diego (Arnold, 1906) Formations; liocene and Pleistocene: Fernando (English, 1914; Soper and Grant, 193E; Kundert, 1952) and Merced (Glen, 1959; Bedrossian, 1974) FormatiorF and Wildcat Group (Ogle, 1953; Faustman, 1964); Pleistocene: Timms oint Silt Member, San Pedro Formation (Arnold, 1906). Lucino a annulata (Reeve) Plate 4,%figures 4, 5, 16, 23, 27 Lucina annulata Reeve, 1 50, p. 17, pl. 4, fig. 17. Phacoides annulata Reeve. Arnold, 1908, pl. 37 , fig. 3. Arnold, 1909, pl. 2, fig. 70. Packard, 1918, p. 263—264, pl. 19, figs. 5a, 5b. Oldroyd, 1924a, p. 126, pl. 33, gs. 5a, 5b. Lucinoma annulata (Reev ). Moore, 1968, p. 40, pl. 18, figs. a—c. Adegoke, 1969, p. 113.‘ Keen, 1971, p. 126, fig. 289. i TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D17 Lucina (Lucinoma) annulata (Reeve). Olsson, 1961, p. 209. Hertlein and Grant, 1972, p. 247, pl. 46, figs. 12, 19. Origimzl description—“Shell orbicular, rather flattened, inequilateral, concentrically laminately ridged, ridges sharp, erect, interstices con- centrically striated, lunule lanceolately ovate, rather deeply excavated; semitransparent white.” Syntypes.—BM(NH) 1963 121/1—2 (Hertlein and Grant, 1972). Type locality.—“Hab. California?”. Holocene. Supplementary description—“Shell large, orbicular, only slightly con— vex, rather thin; umbones depressed, central; surface ornamented by numerous equal, equidistant, sharp, raised, concentric lines; interspaces show lines of growth; lunule small, but deeply impressed and distinct; two sharp cardinal teeth in each valve; lateral teeth nearly obsolete; anterior muscle impression much elongated.” (Arnold, 1903, p. 131) “Lucirwma annulata is “easily recognized by its rounded form, nearly straight posterior dorsal margin and well developed and well spaced (about 2.5 to 3 mm apart) concentric lamellar sculpture.” (Hertlein and Grant, 1972, p. 249) Comparison—“The sculpture is somewhat like that of Lucim, excavate in that between the widely spaced raised concentric ridges are fine growth lines, but this shell [L. annulata]***is much larger—as much as 58 mm in length. (Keen, 1971, p. 126) Comments—One specimen (LACMP 4644) from the San Diego For— mation (pl. 4, fig. 16) is larger (length 61.2 mm, height 56.5 mm) than the largest specimen of Lucinoma acutilirwata (length 42.2 mm, height 39.5 mm) from the Miocene of Washington and Oregon, but a second specimen of L. annulata (LACMP 4643) is 44.3 mm long and 39.0 mm high. In general, L. acutilineata is somewhat more inflated and has a wider escutcheonal area than L. annulata. Geographic range—Living: Alaska to Baja California Sur; fossil: Middle California. Geologic range—Miocene to Holocene. Depending on the inter- pretation of the species, some of the following records could be of L. acutilineata. Occurrence in California—Miocene: Briones (Trask, 1922; Weaver, 1949; Hall, 1958) Formation, Cierbo Sandstone (Hall, 1960), Monterey Formation (Smith, 1912), Neroly Sandstone (Clark, 1915; Weaver, 1949), San Pablo Formation (Hall, 1955) and Santa Margarita (Adegoke, 1969) Formation so-called Bear River (Martin, 1916) series; Miocene and Pliocene: Etchegoin (Martin, 1916; Nomland, 1917a), Purisima (Martin, 1916), and Towsley (Kern, 1973) Formations; Pliocene: upper part of Capistrano (Kern and Wicander, 1974), Careaga (Arnold and Ander- son, 1907), Pomponio Mudstone Member, Purisima (Cummings and others, 1962), Niguel (J .G. Vedder, written commun., 1978); lower part of Saugus (Squires and White, 1983), and so-called San Diego in Santa Monica Mountains (Hoots, 1931) Formations and unnamed sediments in Potrero Canyon, Santa Monica Mountains (Hoots, 1931); Pliocene and Pleistocene: Fernando (Arnold, 1907a; Waterfall, 1929; Durham and Yerkes, 1964; Zinsmeister, 1970), Rio Dell (Roth, 1979), Santa Bar— bara (Dibblee, 1966), and Saugus (Kew, 1924) Formations; Pleistocene: Anchor Silt (Rodda, 1957), Elk River Formation (Roth, 1979) and Timms Point Silt Member, San Pedro Formation (Clark, 1931). Habitat—Essentially a northern species (Keen, 1971, p. 126) at depths of 25 to 750 m (Bernard, 1983, p. 29). Subfamily MILTHINAE Shell relatively solid, generally compressed. Sculpture concentric, faint, irregular to vanishing; anterior scars long. Genus MILTHA H. and A. Adams, 1857 Discoidal, flattened; sculpture of unequal concentric striae; ligament on enlarged nymph. Geographic range—Europe, North America, Australia, New Zealand. D18 Geologic range—Paleocene, New Zealand (Ludbrook, 1969); Eocene to Holocene (table 2). Habitat—35 to 100 m in tropical or subtropical waters. Subgenus MILTHA Large, subcircular to ovate-oblong, slightly inequivalve; surface smooth or lamellose, with faint areas; lunule asymmetrical, striated. Miltha (Miltha) parsoni Waring Plate 6, figure 4 Miltha parsoni Waring, 1917, p. 78, pl. 12, fig. 13. Original description—“Shell sub-circular, convex, rather thick; beak small, pointed, depressed and turned forward; anterior cardinal margin straight and sloping, making a sharp angle with the broadly rounded anterior margin; posterior cardinal margin convex and sloping into broadly rounded posterior margin; surface marked by six major con- centric lines of growth and fine concentric ribs.” Holotype.—CAS/SU 150. Type locality—8U 2697. Ventura County, Calif. Martinez Formation, Paleocene. Comments—The right-valve holotype is subcircular, as first described, but the anterior dorsal margin is broken and the illustration herein is therefore deceptive. The resting stages are very well delineated and the sculpture preserved consists solely of almost evenly spaced, nar- row concentric ridges. Geographic range—Southern California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Waring, 1917; Kew, 1924; Nelson, 1925). Miltha (Miltha) sanctaecrucis (Arnold) Plate 5, figures 5, 7, 11; Plate 6, figure 10 Phacoides (Miltha) sanctaecrucis Arnold, 1909, p. 57—58, pl. 6, fig. 6. Arnold and Anderson, 1910, pl. 28, fig. 6. Loel and Corey, 1932, p. 211, pl. 36, fig. 5. Miltha sanctaecrucis (Arnold). Hanna and Hertlein, 1943, p. 174, fig. 63—18. Stewart, 1946, pl. 17, figs. 5, 8. Woodring and others, 1946, pl. 28, fig. 16. Adegoke, 1969, p. 114. Miltha (Miltha) sanctaecrucis (Arnold). Addicott, 1973, p. 28—29, pl. 3, figs. 5, 10. Original description—“Shell averaging about 75 millimeters in altitude, circular in outline, compressed, concentrically striate. Beaks central, prominent, turned sharply toward the front. Both margins faintly angulated at a point down about one-fourth the distance from beak to base; the posterior dorsal margin the higher and more regularly curved; the anterior dorsal margin shorter and less regular; anterior extremity and base evenly rounded; posterior extremity somewhat trun- cate. Lunule rather narrow, separated from disk by impressed line and a more or less elevated carina; posterior area broadly grooved, extend- ing from beak to extremity, separated from disk by a faint carina and groove. Surface sculptured by fine regular incremental lines and a few faint irregularities of growth. Hinge not exposed in type but believed to be similar to P. [hacoides] childreni Gray.” Holotype.—USNM 165569. Length 74 mm, height 76 mm, width (both valves) 28 mm. Type locality.—USGS 4861. Kern County, Calif. Vaqueros Formation, Oligocene and Miocene. Supplementary description—Miltha sanclaecrucis “is characterized by its large size, circular outline, slight angulation dorsally, compressed disk, prominent lunule and dorsal areas, and finely concentrically striate but otherwise unsculptured surface.” (Arnold, 1909, p. 58) PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA “This large, very slightly inflated lucinid is characterized by very fine, somewhat irregular concentric sculpture. A network of extremely fine, irregular, radial riblets is evident on a few well-preserved specimens.” (Addicott, 1973, p. 29) Comparison.—Miltha sanctaecrucis is generally distinguished from Miltha xantusi by its relatively longer shell and a somewhat longer posterior dorsal slope. Comments—The shell of M. (M .) sanctaecmcis is very thick (4.7 mm on ventral broken edge of holotype), large, and circular in outline. The surface of the shell is covered with fine, continuous radial striae and irregularly spaced concentric grooves. The posterior sulcus on the right valve seems deeper than on the left valve, but the shell is missing on parts of the left valve holotype. Geographic range—Middle and southern California. Geologic range—Oligocene to Pleistocene. According to Hertlein and Grant (1972, p. 251), most of the records of M. sanctaecrucis from beds of Pliocene age in southern California are referrable to M. xantusi. Occurrence in California.—— Oligocene: So-called Phacoides Sand, (Addicott, 1972) and Wygal Sandstone (Addicott, 1973) Member, Temblor (Smith, 1912; Dickerson, 1914; Woodford, 1925; Woodring and others, 1940; Adegoke, 1969; Addicott, 1973) Formation; Oligocene and Miocene: Vaqueros (Arnold, 1909; Smith, 1912; Loel and Corey, 1932; Adegoke, 1969), and Vaqueros Sespe undifferentiated (Schoellhamer and others, 1981) Formations; Miocene: Altamira Shale Member, Monterey (Woodring and others, 1946), Buttonbed Sandstone Member and Cameros Sandstone Member, Temblor (Addicott, 1972) McLure Shale Member, Monterey (Stewart 1946; Adegoke, 1969), Monterey (Smith, 1912), Olcese Sand (Addicott, 1965), Round Mountain Silt (Keen, 1943), Santa Margarita (Clark, 1915; Nomland, 1917b; Adegoke, 1969) and Topanga (Kew, 1924; Hoots, 1931; Woodring, 1931; Neuerberg, 1953; and Schoellhamer and others, 1981) Formations; Miocene and Pliocene: Etchegoin (Adegoke, 1969) Formation; Pliocene and Pleistocene: Fernando Formation (English, 1914; Adegoke, 1969). Habitat.—Miltha samtaecrucis is recognized in paleoclimatic analyses as a warm-water indicator because it occurs in the tropical Panamic molluscan province (Addicott and Vedder, 1963). Miltha (Miltha) xantusi (Dall) Plate 5, figures 1—4, 12; Plate 6, figures 1, 2, 11 Phacoides (Miltha) xantusi Dall, 1905, p. 111. Phacoides wantusi Dall. Hanna, G D., 1926, p. 474—475, pl. 28, fig. 7; pl. 29, fig. 1. Lucina (Miltha) xantusi Dall. Grant and Gale, 1931, p. 291, pl. 14, figs. 20a, 20b. Hertlein and Strong, 1946, p. 115, pl. 1, fig. 13. Miltha xantusi Dall. Durham, 1950, p. 77, pl. 19, figs. 3, 8.01sson, 1961, p. 215, pl. 30, fig. 4. Moore, 1968, p. 40, pl. 18, figs. e, f. Miltha (Miltha) xantusi (Dall). Keen, 1971, p. 125—126, fig. 187. Hertlein and Grant, 1972, p. 250—251, pl. 45, figs. 14—17. P[hacoides] joannis Dall, 1905, p. 110—112. Original description—“The P. xantusi seems to be a smaller species when adult, more rounded, more equivalved and with a shorter liga- ment. It has a more or less bifurcate and vermiculate radial sculpture, that of P. childreni being finer, more regular and more distinctly divid- ed into fine continuous radial grooves and a microscopic minor sculpture between them. “As in many other Lucinacea, directly under the beaks there is a small impressed area. In P. mntusi this in the right valve projects so as to fill an excavation in the other valve and is so much impressed as to make the beak appear sharper and more produced and to distinctly arcuate the two cardinal teeth****ln the California species the lunule is very small and bent vertically downward so that in the closed valves it is ex- cavated and not projecting and has a length of about 6 mm. It is almost wholly confined to the right valve.” Holotype.—USNM 5383. j.‘ LoLgLOgegh 4 4h ‘4# ML 3 .8 TlERTIARY MARINE PELECYPODS; LUCINIDAE THROUGH CHAMIDAE Type locality—Gabe San Lucals, Baja California Sur. Holocene. Supplementary descriptibn.—“'Ilhere is considerable variation in shape and in the degree of convexity. Ydung shells are generally more rounded in outline. Many shells, especially large ones, are elongated from beak to base. The left valve is usuall flatter than the right, but in some specimens the valves are of near] equal convexity, and occasionally the left valve may be the more conv%x of the two. The lunule as described by Dall is mostly in the right va ve, is impressed, and is about 6 mm in length. On some specimens alsubmedian slight depression or faint broad groove extends from the limbo to the base, but on others it is lacking. The right valve has two dardinal teeth, slightly grooved in large specimens, the left valve with a s orter anterior cardinal and a posterior cardinal (sometimes faintly grooyed) and a long posterior nymph. The interior of the valves sometimes bears fine pits, in others the interior may be thickened in part with shbll material. The margins are smooth. Externally the surface is sculpt red with concentric lines of growth, occasionally with deeper grooves bnd often with faint radial lines visible, especially on the medial portionl of the valves.” (Hertlein and Grant, 1972, p. 251) ‘ Comparison—“M. caloosaensis (Dall), common in the Pliocene of Florida, is similar to M. :canthusi in general characters; it often reaches a much larger size; the interior lbecomes much thickened in the adult and the adductor scars deeply inbet; its left valve is generally the more convex, the reverse of the condition found in M. xanthusi.” (Olsson, 1961, p. 215) “The valves of M. sanctae ' i (Arnold) are thicker, more nearly equal in convexity and more circular n outline in comparison with M. xan- tusi.” (Hertlein and Grant, 197 , p. 251) Comments—According to He tlein and Grant (1972, p. 251), most of the records of Miltha sanctaecrudis from beds of Pliocene age in southern California are referable to M. leantusi although specimens from the Imperial Formation may be pr perly assigned. Geographic range—Living: aja California Sur to Mexico; fossil: middle California to Baja Calif rnia Sur. Geologic range—Miocene to olocene. Occurrence in the Californias. Miocene: Castaic (Stanton, 1966) Santa Margarita (Preston, 1931; Addicott and Vedder, 1963), and Tortugas (Minch and others, 1976) Formations; Miocene or Pliocene: Imperial For— mation (GD. Hanna, 1926; Hert ein and Grant, 1972; Bell-Countryman, 1984); Miocene and Pliocene: tchegoin (Wilson, 1943) and Towsley (Kern, 1973) Formation; Plioce e: upper part of Almejas (Smith, 1984), Niguel (J. Vedder, written co mun., 1978), and San Diego (Hertlein and Grant, 1972) Formations; liocene and Pleistocene: Pico Forma- tion (W interer and Durham, 1962); Unnamed strata on Islas Coronados, Golfo de California (Durham, 1950; Emerson and Hertlein, 1964) and at Puente El Pulpito (Hertlein 1957). Habitat—33 to 101 m (Hertlein and Grant, 1972, p. 251). Subgeniis MILTHA? Miltha (Miltha?) meganbsensis (Clark and Woodford) Plate 5i figures 6, 8, 9 Phacoides meganosensis Clark %nd Woodford, 1927, p. 93, pl. 15, figs. 8—10. Original description—“Shell medium in size, subcircular in outline, moderately gibbous; beaks rather inconspiuous, subcentral, only very slightly prosogyrous. Anterior dbrsal edge straight; posterior dorsal edge slightly convex; anterior end broadly rounded; posterior end broadly subtruncate; ventral edge str ngly and regularly arcuate. There is a well defined umbonal sinus alo%g the posterior dorsal margin extending from just back of the beaks to he posterior end, also a depressed area bordering the anterior dorsal ledge which is separated from the main surface of the shell by an obscure umbonal sinus similar to that posterior to the beaks. Surface sculptured by numerous regular concentric ribs, D19 the interspaces between which are twice as wide as the ribs. The rib- bing and interspaces are covered by finer incremental lines. Surface also ornamented by numerous fine, radiating ribs. On some of the specimens this radiating ribbing is very faint to obsolete, on others it is well developed. Lunule strongly depressed, elongate, narrow. Some rather imperfectly exposed hinges of this species were obtained, suffi- cient to show that the cardinals and laterals are well developed. Anterior muscle scar elongate, expanding ventrally, 18 mm. long; 4 mm. in greatest width. These measurements were taken from a shell 33 mm. long. Dimensions—Type: Height 28 mm., length (posterior end broken) 27 mm.” Holotype.—UCMP 31303. Type locality—U0 3159. Contra Costa County, Calif. Meganos For» mation, Paleocene. Comparison—“This species resembles somewhat Phacoides gyrata (Gabb), from which it differs by its greater convexity, finer and more regular ribbing, and smaller size.” (Clark and Woodford, 1927, p. 93) Comments.—Paratype UCMP 31305 shows the fine, radiating ribs described by Clark and Woodford (1927). Geographic range—Middle California. Geologic range—Paleocene. Occurrence in California—Paleocene: Meganos Formation (Clark and Woodford, 1927). Miltha (Miltha?) jacalitosana (Arnold) Plate 9, figure 6 Paphia jacalitosana Arnold, 1909, p. 66—67, pl. 16, fig. 3. Lucina (Miltha?) jacalilosana (Arnold). Grant and Gale, 1931, p. 292. Original description—“Shell attaining an altitude of over 50 milli- meters, subcircular in outline, compressed, concentrically and finely radiately sculptured. Beaks small, turned sharply forward, situated about one-third the length from anterior to posterior extremity; both anterior and posterior margins and base regularly rounded. Lunule small, im- pressed. Surface sculptured by numerous equidistant slightly elevated concentric laminae and numerous fine, close-set radiating raised lines. Hinge and interior not visible.” Holotype.—USNM 165587. Type locality.—USGS 4765. Fresno County, Calif. Etchegoin Forma- tion, Miocene and Pliocene. Supplementary description—“Miltha jacalitosana is readily dis- tinguishable by its moderate size, circular outline, compressed form, and rather inconspicuous radiating sculpture.” (Arnold, 1909, p. 66) Comments—The holotype is venerid in outline but the valves are only moderately inflated. The shell is missing except for one small patch of thick shell on the left valve. The hinge is not exposed. Geographic range—Middle California. Geologic range—Miocene and Pliocene. Occurrence in California—Miocene and Pliocene: Etchegoin Forma- tion (Arnold, 1909). Genus CLAIBORNITES Stewart, 1930 Medium-sized, lenticular, flattened; sculpture of concentric striae, dorsal areas obsolete; lunule lanceolate. Hinge with narrow cardinals and strong anterior laterals; shell margin internally smooth. Geographic range—Europe, North America. Geologic range—Paleocene to Oligocene (table 2). Subgenus CLAIBORNITES Geographic range—United States. Geologic range—Eocene. D20 Claibornites (Claibornites) diegoensis (Dickerson) Plate 6, figures 3, 5, 7 Lucina diegoensis Dickerson, 1916, p. 484, pl. 37, figs. 1a, 1b. M.A. Hanna, 1927, p. 284. Claibornites diegoensis (Dickerson). Givens, 1974, p. 45—46, pl. 1, fig. 15. Squires, 1984, p. 45, fig. 10m. Original description—“Shell medium in size, orbicular; thick, with central prominent beaks. Lunule wide, short, and very prominent; escut- cheon long, narrow; anterior dorsal margin markedly concave under the beaks; the slightly convex posterior dorsal margin slopes with moderate angle to a truncated posterior end; ventral margin nearly semi- circular; right and left valves equal. The surface is marked by strong, sharp concentric incremental lines and by a feebly developed umbonal groove which extends to the middle of the posterior extremity.” Holotype.—UCMP 11788. Type locality—U0 2226. San Diego County, Calif. Ardath Shale, Eocene. Supplementary description. —Claibornites diegoensis “is characterized by its compressed, discoidal shape; obsolete posterior areas; com letely submerged ligament; and deeply excavated lunule that partly 0b cures the anterior cardinal tooth.***lt is referred to Claibornites beca se of the presence of a strong right anterior lateral tooth. The lateral teeth are obsolete in Saxolucina.” (Givens, 1974, p. 46) Geographic range—Southern California. Geologic range—Eocene. Occurrence in California—Eocene: Ardath Shale (Givens, 1974), Avenal Sandstone (Kappeler and others, 1984), Delmar Sand (M.A. Hanna, 1927), J uncal (Givens, 197 4), La J olla (M.A. Hanna, 1927), Llajas (Squires, 1984), and Tejon (Dickerson, 1916) Formations. Subgenus CODALUCINA Stewart, 1930 Thin, sculpture finely concentric; ligament deeply sunken, in broad groove. Hinge with well-marked cardinals and anterior laterals, weak posterior laterals. Geographic range—Europe, North America. Geologic range—Paleocene to Oligocene (table 2). Claibomites (Codalucina) muirensis (Dickerson) Plate 6, figures 6, 8 Phacoides muirensis Dickerson, 1914, p. 132, pl. 10, figs. 11a, 11b. Original description—“Shell small, suborbicular, convex; beaks nearly central; in some specimens slightly posterior to the center. Lunule nar- row, small; escutcheon long, narrow; posterior dorsal margin nearly straight; anterior dorsal margin slightly excavated under the beaks; anterior and posterior extremities subtruncate; ventral margin broadly rounded. Surface is marked by strong concentric growth lines and by a very faint, narrow, posterior furrow which is absent in young specimens.” Holotype.—UCMP 11682. Type locality—U0 243. Contra Costa County, Calif. Martinez For- mation, Paleocene. Comparison—“This species differs from Phacoides turneri (Stanton) in the truncation of the extremities, in the slightly posterior position of the beak and in the lesser prominence of the posterior furrow.” (Weaver, 1942, p. 149) Comments—The hinge is not exposed on the holotype of Claibornites (Codalucina) muirensis, therefore, it is assigned to Codalucina solely on the basis of its outline and sculpture. Geographic range—Middle California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez Formation (Dicker- son, 1914). PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Claibornites (Codalucina) turneri (Stanton) Plate 7, figures 2, 7 Lucina turneri Stanton, 1896, p. 1042, pl. 65, figs. 6, 7. Phacoides turneri (Stanton). Dickerson, 1914, p. 151, pl. 10, fig. 8. Original description—“Shell large thick, moderately convex, subcir- cular in outline; beaks rather prominent; lunule small; surface nearly smooth, marked only by lines of growth, except in the posterior dorsal region, where there is a narrow but distinct furrow, bordered above by a somewhat broader rounded ridge extending from near the beak to the posterior end; dorsal margin slightly excavated in front of the beaks. “The left valve has two well-developed cardinal teeth and obsolescent anterior and posterior laterals.” Syntypes.—USNM 108971. Right valve 35 mm high, 37 mm (incom- plete) wide; left valve 55 mm long, 49 mm high, and the shell is about 2 mm thick. Type locality—One mile [1.6 km] southeast of Lower Lake [NE 1/4, sec. 11, T. 12 N., R. 7 W.]. Lake County, Calif. Martinez Formation, Paleocene. Comments—Two specimens and one gutta-percha cast are in the type lot. One shows the interior of a right-valve hinge (pl. 7, fig. 7); the other the exterior of a left valve. The shell is thick, subcircular, and much inflated. The shell seems to have had irregularly spaced concentric ridges and grooves. Geographic range—Middle California. Geologic range—Paleocene and Eocene. Occurrence in California.—Paleocene: Martinez Formation (Arnold, 1906; Dickerson, 1914); Paleocene and Eocene: Lodo Formation (Smith, 1975) Genus GIBBOLUCINA Cossmann, 1904 Irregularly compressed; sculpture of coarse lamellae or ribs; lunule concave, short, broad. Fine radial internal threads; shell margin in- ternally smooth. Geographic range—Europe, America, Australia, Africa. Geologic range—Cretaceous to Holocene (table 3). Subgenus EOMILTHA Cossmann, 1910 Medium-sized, almost flat, transversely subrhomboidal; with more or less elevated concentric lamellae; lunule not sunken. Cardinals well defined. Geographic range—Europe, America, East Africa. Gibbolucina (Eomiltha) gyrata (Gabb) Plate 7, figure 1 Dosinia gyrata Gabb, 1864, p. 168, 232, pl. 23, fig. 148. Lucina gyrata (Gabb). Anderson and Hanna, 1925, p. 168—169. Phacoiales gyrata (Gabb). Clark and Woodford, 1927, p. 93. Miltha (Eomiltha)gyrata (Gabb). Stewart, 1930, p. 192, pl. 12, fig. 11. Original description—“Shell lenticular, nearly circular; beaks small, central, inclined anteriorly; cardinal line curved, sloping downwards, and uniting with the posterior margin; length and breadth about equal. Surface marked by numerous irregular lines of growth, crossed by a few indistinct, radiating lines. Lunule small, deeply impressed.” Holotype.—UCMP 11986. Type locality— Common at Marsh’s, southeast of Mount Diablo. Contra Costa County, Calif. Domengine Formation, Eocene. Supplementary description—“The extremely compressed form of this shell is one of its most prominent characters. The thickness of the specimen figured, measured from the external surfaces of the shell, is not more than three-tenths of an inch. (Gabb, 1864, p. 168) TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE “The type of P. gyrata***has lost its hinge. However, other specimens from the same collection show a thoides hinge with two strong cardinal teeth. These specimens correspond both externally and internally to our material which comes from the ype locality on Marsh’s ranch. “On the better preserved speci ens there is a well defined umbonal sinus which extends from the umbones to the posterior end.” (Clark and Woodford, 1927, p. 93) Geographic range—Middle an southern California. Geologic range—Paleocene an Eocene. Occurrence in California—P leocene: Meganos Formation (Clark, 1921; Clark and Woodford, 19 7; Clark and Vokes, 1936); Eocene: Domengine (Gabb, 1864), Muir Sa dstone (Weaver, 1953) and Tejon For- mation (Dickerson, 1915). ‘ Subgenus lEOMILTHA? Gibbolucina (Eomil ha?) [Jacki (Dickerson) Plate‘G, figure 9 Lucina packi Dickerson, 1916, p. 484, pl. 36, fig. 12. Turner, 1938, p. 52, pl. 9, fig. 11. l Miltha (Eomiltha?) packi (Dickerson). Vokes, 1939, p. 72. Original description—“Shell mall, subcircular in outline; posterior dorsal margin straight with moderate slope to a subtruncate posterior; beak subcentral, rounded, promi ent; decoration consisting of very fine sharp concentric lines of groth.” Holotype.—UCMP 11787. Type locality—U0 672. Fresn County, Calif. Domengine Formation (Keen and Bentson, 1944), E00 ne. Supplementary description. “The type is an immature individual; adult specimens attain a much g eater size. The posterior dorsal region of the shell has two grooves: one bounding the area, runs from the beak to the straight posterior margi ; the other extends from the beak to the middle of the posterior exti‘emity. Anterior to the beak is a small groove extending to the anteribr dorsal edge. “This species is questionably heferred to Eomiltha as it differs from Miltha (sensu stricto) only in the absence of the posterior lateral. In the type of Eomiltha and also inl the Claiborne species M. (E'omiltha) pandata, the interior of the shell is rugose and roughened. In M. packi this is smooth as in Miltha (sensu stricto). The Miocene form Miltha (Miltha) sanctaecrucis (Arnold shows great variation in the develop— ment of this lateral and in som specimens it is entirely obsolete. It is suggested that Miltha (sensu st 'cto) may have originated in the Califor- nia province, with M. packi as n ancestral type.” (Vokes, 1939, p. 72) Ornaments—On the holotype, he concentric ridges, very closely spaced on most of the shell, are twice 5 widely spaced as they cross the first posterior groove and four time as widely spaced at the posterior dor- sal margin. Geographic range—Southern) Oregon to southern California. Geologic range—Eocene. l Occurrence in California—Eocene: Avenal, La Jolla, Llajas, (Vokes, 1939), and Tejon (Dickerson, 1916) Formations. l Genus MYRTlUCINA Vokes, 1939 Medium-sized, compressed, thansversely rounded, sculpture solely of irregular lamellose growths. Geographic range—Europe land North America. Geologic range—Eocene (talile 3). Myrtucina rdfeburgensis (Turner) Plate‘ 7, figures 3, 8 Lucina roseburgensis Hendon ’in Turner, 1938, p. 51, pl. 9, figs. 12, 13. Myrtea (Myrtucina) roseburgemsis Hendon in Turner. Vokes, 1939, p. 73, pl. 10, figs. 11, 13—15r D21 Original description—“Shell thin, subquadrate, moderately com- pressed, ornamented by prominent irregularly spaced growth lines; beaks low; ligament almost submerged; lunule short, slightly depressed. Left hinge with one centrally placed cardinal and obscure anterior and posterior laterals.” Holotype.—UCMP 33665. Type locality—U0 139. On north bank of North Umpqua River up- stream from the bend a quarter of a mile north of Glide. Douglas County, Oreg. Umpqua Formation, Eocene. Supplementary description—“In Lucina roseburgensis Turner the right cardinal is trigonal in shape and directed posteriorly; the anterior and posterior cardinals of the left valve are of equal strength, the anterior being slightly curved, the posterior straight. The laterals are received upon the hinge—plate on a platform-like swelling. The lunule is unequally divided between the valves, the larger portion being in the right valve. Externally the shape of this species is more typically lucinoid than in Myrtea (sensu stricto), but the sculpturing consists solely of growthlines.” (Vokes, 1939, p. 73) Comparison—The new species is large and has a slightly more quadrate outline than L. diabloi [diaboli] Dickerson.” (Turner, 1938, p. 51) Geographic range—Oregon to southern California. Geologic range—Eocene. Occurrence in California—Eocene: Avenal Sandstone and Domengine Formation (Vokes, 1939). Genus PEGOPHYSEMA Stewart, 1930 Rounded, tumid, slightly inequilateral; sculpture of irregular growths, with lunule narrow, depressed. Cardinal plate triangular without pro- tuberances; shell margin internally smooth. Geographic range—Europe, north Africa, and North America. Geologic range—Eocene to Holocene (table 3). Subgenus PEGOPHYSEMA Subcircular; surface with coarse concentric ribs and well-marked, subalate, anterior area. Trigonal hinge plate, without teeth. Geographic range—Europe and North America. Geologic range—Oligocene to Holocene. Pegophysema (Pegophysema) edentuloides (Verrill) Plate 11, figures 7, 8, 11 Loripes edcntuloides Verrill, 1870, p. 226. Lucina edentuloides (V errill). Dall, 1901, p. 802—803. Hanna, 1926, p. 466. Anodontia edentuloides (V errill). Grant and Gale, 1931, p. 292. Hertlein and Strong, 1946, pt. 4, p. 117. Durham, 1950, p. 75, pl. 18, figs. 11, 16. Anodontia (Anodontia) edentuloides (Verrill). Olsson, 1961, p. 221, pl. 30, figs. 1—1b. Pegophysema edentuloiales (Verrill). Keen, 1971, p. 126, fig. 228. Original description—“Closely allied to L.[oripes] edentula of the West Indies and Gulf of Mexico. “It is subglobose, and much more swollen than L. edentula. The apex is more prominent and curved, and the lunular region more deeply ex— cavated. The ligament is shorter and its supporting plate is not so stout, and its inner edge but little elevated above the ligament groove.” Holotype.—Missing and presumed lost. Type locality—La Paz, Baja California Sur. Holocene. Supplementary description—“The hinge is without teeth except in very young specimens; mature adults are inflated and nearly smooth, but juvenile shells are flatter, with weak furrows setting off dorsal areas, D22 especially in anterior area. Length, to 65 mm (average about 45 mm); average height, 40 mm***The name Anodontia Link, 1807, has been used for these species, but the type species of that group, which is western Pacific in distribution, has a number of significant points of difference-the ligament sinks down posteriorly into the shell cavity, without any supporting nymph; the hinge plate has a faint pustular cardinal tooth; and the anterior adductor muscle scar is relatively short.” (Keen, 1971, p. 126) Comparison—According to Olsson (1961, p. 221), P. edentuloides has a shorter ligament than P. edentula and its supporting plate is not so stout, its inner edge being but little elevated above the ligament groove. Geographic range—Living: Baja California Norte to Mexico; Fossil: southern California to Baja California Sur. Geologic range—Miocene or Pliocene to Holocene. Occurrence in Californias—Miocene or Pliocene: Imperial Formation (G D. Hanna, 1926); Pleistocene: unnamed sediments at Bahia Santa Inez, Baja California Sur. Habitat—33 to 165 m (Keen, 1971); 35 to 170 m (Bernard, 1983). Subfamily DIVARICELLINAE Genus DIVARICELLA von Martens, 1880 Rounded, with small lunule. Shell margin internally smooth but in- cised or exceeded by terminations of ribs. Geographic range—Africa, Indian Ocean, Asia, Australia, Central America; California?. Geologic range.—Eocene(?); Pliocene to Holocene. Genus DIVARICELLA? Subgenus EGRACINA Chavan, 1951 Relatively flattened, divaricated by large flattened ribs with narrow interspaces. Terminations of ribs incising margin. Geographic range—Central America, Africa; California‘l. Geologic range.—Eocene(?); Pleistocene to Holocene (table 3). Subgenus EGRAC INA? Divaricella? (Egracina?) cumulata (Gabb) Plate 7, figures 5, 6 Lucina cumulata Gabb, 1864, p. 176, pl. 24, fig. 254. Dickerson, 1915, p. 80, pl. 2, fig. 4. Divaricella cumulata Gabb. Anderson and Hanna, 1925, p. 171. Original description—“Shell minute, subcircular, thick; beaks large, subcentral; ends and base regularly rounded; anterior end slightly emarginate immediately under the beaks; cardinal margin nearly straight, uniting with the posterior end by a rounded angle. Surface marked by 4 or more enormous rounded concentric ribs, giving the shell the appearence of being composed of a number of independent masses laid one over another; besides these ribs there are a few small, oblique, divaricating, impressed lines, most marked near the apex." Holotype.—UCMP 11988. Type locality—Near Fort Tejon. Kern County, Calif. Tejon Forma- tion, Eocene. Supplementary description—“The collections of the Academy of Sciences contain six specimens from Loc. 244****The divaricate sculpture in all of them extends entirely to the margin of the shell, a feature not shown in the original figure. No other species of the genus Divaricella is known to have such heavy concentric ridges as this.” (Anderson and Hanna, 1925, p. 171) Comments—The small right-valve holotype was described by Gabb as having “enormous concentric ribs”. These “ribs” seem to be ledges PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA produced by resting stages. The divaricate sculpture incises the shell margin, and the ribs are wide and flattened; these characters differen- tiate the subgenus Egracina to which “Lucirw.” cummulata is tentatively assigned. Geographic range—Southern California. Geologic range—Eocene. Occurrence in California—Eocene: Tejon Formation (Arnold and Anderson, 1907; Dickerson, 1915; Anderson and Hanna, 1925). Genus DIVALINGA Chavan, 1951 Orbicular, inflated; divaricated by broad flattened ribs with narrow interspaces; lunule slightly depressed, dissymmetric; ligament external. Hinge with well-developed cardinals and laterals; anterior scars short; shell margin internally denticulate. Geographic range—Europe, North American, Central America, Africa. Geologic range—Eocene to Holocene (table 3). Subgenus DIVALINGA Anterior scars slightly divergent from pallial line. Geographic range—Europe, North America, Central America. Geologic range—Oligocene to Holocene. Divalinga (Divalinga) cbumea (Reeve) Plate 7, figures 10, 11, 13, 14 Lucina eburnea Reeve, 1850, pl. 8, fig. 49. Diraricella lucasana Dall and Ochsner, 1928, p. 122, pl. 2, figs 17, 21, 24. [New name for D. eburnea thought preoccupied by D. eburnea Deshayes, a nomen nudum.] Durham, 1950, p. 78, pl. 19, figs. 5, 15. Divaricella eburnea (Reeve). Olsson, 1961, p. 220, pl. 31, fig. 2. G D. Hanna, 1926, p. 464—465, pl. 26, figs. 8, 9. Divalinga (Divalinga) eburnea (Reeve). Keen, 1971, p. 125, fig. 285. Divaricella columbiensis Lamy, 1934, p. 433. Original description.—“Luc. testa orbiculari, globoso-convexo solidius- cula, bifariam sulcata-striata, striis ante medium regulariter divaricatis; pelucido-alba. “Shell orbicular, globosely convex, rather solid, groove—striated in two ways, striae regularly divaricate before the middle; transparent white." Holotype.—Location unknown. Type locality—St. Elena, West Colombia and Panama [Ecuador] (in sandy mud at a depth of 11 fathoms). Supplementary description—“Adult shell reaching a length of about 24 mm, relatively heavy, often becomes thickened, coarsely punctate, or chalky internally. Umbones and beaks more nearly medial than in the next species [Divaricella perparvula Dall]. Lunule small. Sculpture usually coarse, forming sharply acute angles in the bend of the lines of divarication; an underlying fine radial striation or internal radial struc- ture usually visible, often strong.” (Olsson, 1961, p. 220) Comparison—“More globose in form than the two preceding species [divaricata and ornata], with the divaricating grooves rather more distant from each other, more circularly disposed at the sides, and not denticulated at the margin.” (Reeve, 1850, pl. 8 explanation) Divaricella perparvula Dall has a “Shell much like D. eburnea show- ing the same range in size but usually heavier and more convex. Angle of divarication in the incised lines is rounded, blunt, or obtuse. Lunule although quite small is distinct, deep, often with a widely flaring edge. Nepionic shell large, visible, and sculptured with fine, close-set concen- tric threads. Hinge strong, the cardinal and lateral teeth large and well developed at all stages.” (Olsson, 1961, p. 220) Comments—The line of divarication commonly is doubled near the ventral margin forming two peaks. T‘iERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE Geographic range—Living: liaja California Sur to Peru; fossil: southern California to Baja California Sur. Geologic range—Miocene or Pliocene to Holocene. Occurrence in Californias.—M ocene: Comondu Formation (Durham, 1950); Miocene or Pliocene: Impe 'al Formation (Kew, 1914; GD. Hanna, 1926); Pliocene: Comondu and arquer Formations (Durham, 1950); Pleistocene: Santa Rosalia (Wils n, 1948; Wilson and Rocha, 1955), un- named sediments of Bahia Santa nez, Islas Coronados, (Durham, 1950; Hertlein, 1957), Bahia Magdalenia (G D. Hanna, 1926), Isla Monserrate (Emerson and Hertlein, 1964), Puente El Pulpito and Puente Coyote (Hertlein, 1957). Habitat.—Intertidally to deptiu of 55 m. Family liUCINIDAE? Genus uncertain “Lucina’i’ nasuta Gabb Platei5, figure 10 Lucina nasuta Gabb, 1864, p. 1‘75, pl. 24, fig. 158 [error for fig. 159]. ”Lucina” nasuta Gabb. Stewai‘t, 1930, p. 182—183, pl. 7, fig. 4. Original description—“Shell imall, very thin, subcompressed, inequi- lateral; beaks small, acute, noti prominent, placed a little behind the middle; anterior end broadly r unded and very prominent; posterior cardinal margin straight, slopin downwards to unite with the posterior end, which is narrow, produced and subtruncate; basal margin convex, most prominent in advance of tile middle, slightly sinuated posteriorly; umbonal ridge subangular, stra ght. Surface polished, marked by faint, concentric lines of growth, and liy almost imperceptible radiating lines.” Holotype.~ANSP 4465. i Type locality—Martinez, Contra Costa County, Calif. Domengine For- mation, Eocene. Comments.—“Lucina” nasutF probably is a tellinid as suggested by Stewart (1930, p. 183). Occurrence in Calilfmnia—Eoicene: Tejon Formation (Dickerson, 1915) and Domengine Formation (Weaver, 1949). i “Lucina” gaylordi (Wagner and Schilling) Plate 7, figures 16, 18, 20 Phacoides gaylordi Wagner arid Schilling, 1923, p. 254, pl. 45, fig. 5. “Lucina” gaylordi (Wagner aiid Schilling). Schenck and Keen, 1940, pl. 28, fig. 5. i Original description—“She 1 medium in size; subquadrate to ovate; convex; equivalved; inequilate al; beaks nearly central; slightly proso- gyrous; length greater than hei ht; lunule distinct; ligamental area long; anterior and posterior dorsal m rgins straight; anterior extremity broad— ly and regularly rounded; pos erior extremity subtruncate; a slightly depressed area extends below the anterior dorsal margin from the beaks to the anterior extremity; posterior depression apparently less promi- nent; shell sculptured by sharp well defined concentric lamellae, which become more closely spaced to ards the ventral edge; hinge unknown. Dimensions: length, 29 mm.; eight, 22 mm.; convexity 15 mm.” Holotype.—CAS 6176. Type locality—Southern Pacific Geology Dept. Paleo. loc. 321. “Devil’s Kitchen, 1/4 mi [0.4 km] above rioad, San Emigdio Cr.” (Keen and Bent- son, 1944). Kern County, Calif, San Emigdio Formation, Eocene. Comments.—The hinge is not exposed on the holotype of “Lucina” gaylordi, and Wagner and Sch lling stated that the hinge was unknown. The straight hinge line and :iuncentric lamellae are comparable with Lucinoma, but the subquadr te outline is not typical of that genus. Geographic range—Southerin California. Geologic range—Eocene. i Occurrence in California.— ocene: San Emigdio Formation (Wagner and Schilling, 1923; DeLise, 1967). D23 “Lucina” wattsi Loel and Corey Plate 11, figures 2-4 Lucina wattsi Loel and Corey, 1932, p. 209—210, pl. 36, figs. 72., 7b. Original description—Shell medium sized, suborbicular; valves very convex, slightly inequilateral and somewhat inequivalve, the left valve with a more flattened posterior dorsal area than the right; beaks prom- inent, anterior to middle, proximate; posterior dorsal margin long, nearly straight, meeting the posterior margin in an abrupt angle; anterior dorsal margin short, concave before beaks, sharply rounding to the anterior margin; the whole periphery from ends of dorsal margins being nearly circular. Surface not preserved entirely, but was apparently marked only by uneven concentric lamellae and, on the posterior flattened area, a few radiating ribs. Large cotype: length, 39 mm.; height, 38 mm.; diameter (through both valves), 23 mm. Smaller cotype: length, 34 mm.; height, 33 mm.; diameter, 19 mm.” Syntypes.—UCMP 31821, 31822. Type locality.—UCMP A 601. “Canyon del Cordon, Lower Califor- nia. * * *Vaqueros horizon”. Geographic range—Southern California to Baja California Norte. Geologic range—Oligocene and Miocene. Occurrence in Californias.—Oligocene and Miocene: Vaqueros For- mation (Loel and Corey, 1932) and so-called Vaqueros Formation in Baja California Norte (Loel and Corey, 1932). “Lucina (Here) excavata temblorensis” Adegoke Plate 3, figures 3, 4 Lucina (Here) ereaoata temblorensis Adegoke, 1969, p. 115, pl. 4, figs. 8, 11, 12. Original description—“Shell medium sized, thin, moderately convex, subtrigonal; beak prominent, prosogyrous; lunule well developed, moderately excavated, slightly penetrating hinge plate; anterior dor- sal edge fairly long, concave immediately below beak (in lunular area), merges into sharply rounded anterior ventral margin leaving a fairly well defined shoulder; posterior dorsal margin shorter than anterior dorsal margin, straight or slightly convex, forms well defined angle at junction with ventral margin; ventral margin broadly rounded; shell sur— face sculptured with few, narrow, distant, rounded concentric ribs; dentition similar to that of L. excavata Carpenter.” Holotype.—UCMP 36676. Type locality.—UC D—1074. Kern County, Calif. Temblor Formation, Oligocene and Miocene. Comparison—Here excavata temblorensis “***differs from Lucina (Here) ercavata, s. s. and L. (H .) richtofeni Gabb by its less convex shell, the latter two species have very convex valves and are said to resemble ‘nuts’. L. (H .) ercavata Carpenter has less prominent beaks, a more cir- cular outline, more rounded posterior dorsal margin and more depressed anterior dorsal margin.” (Adegoke, 1969, p. 115) Comments—This species seems to be a venerid. Geographic range—Southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Temblor Forma- tion (Adegoke, 1969). P. [hacoides] joannis (Dall), nomen nudum P. joannis Dall, 1905, p. 112. M. [iltha] joannis (Dall). Olsson, 1961, p. 215. Original description—”It is interesting to find that the Florida Pliocene, P. [hacoides] caloosana Dall, though smaller, has the upraised lunule like that of Brazil; while the Pliocene, P. joannis Dall of San Juan, Lower California (opposite Guaymas), resembles the recent P. xantusi in having the folded lunule, only, in this case, the margin is more deeply infolded and the shell heavier, more elongate-oval, and about one-fourth D24 smaller. It measures 55 mm. in height by 51 mm. in width; P. xantusi, 71x65 mm., and P. childreni, 86x77 mm.” Commts.—Miltha? joamiis was incompletely described, not figured, and no type material is known to me. It is herein rejected as a nomen nudum. Family THYASIRIDAE Genus THYASIRA Leach in Lamarck, 1818 Shell subcircular to subquadrate, moderately inflated, beaks strong- ly curved anteriorly; posterior side furrowed or sharply angulated; sculpture of growth lines only. Geographic range—Cosmopolitan. Geologic range—Cretaceous to Holocene. Eocene to Holocene in the Eastern Pacific (Hertlein and Grant, 1972, p. 255) (table 4). Habitat—Intertidal to 10,005 m, mostly in cool waters (Hertlein and Grant, 1972, p. 255) Subgenus THYASIRA Thyasira (Thyasira) gouldii (Philippi) Plate 7, figures 4, 21 Lucinaflexuosa Montagu in Gould, 1841, p. 71, fig. 52. Not Tellinaflex- uosa Montagu, 1803. L[uciria]. Gouldii Philippi, 1845, p. 75. Cryptodonfleamosus (Montagu). Dall, 1874, p. 297. Not Cryptodonfiex- uosus Montagu, 1841. Thyasira gouldii (Philippi). Dall, 1901, p. 786, 790. Arnold, 1903, p. 135—136. Packard, 1918, p. 264—265, pl. 20, fig. 5. Oldroyd, 1924a, p. 120, pl. 34, fig. 5. Hertlein and Grant, 1972, p. 255—257, pl. 43, figs. 17, 21. Thyasira gouldi (Philippi). Packard, 1918, p. 264, pl. 20, fig. 5. Original description—“Von Lucimflexuosa sagt Gould, p. 72: "there can be no doubt, that this is identical with the British shell, though the specimens I have seen are much smaller than the foreign specimens usually are’. Bei einer aufmerksamen Betrachtung findet man diessen, ausser dem sehr auffallenden Unterschied in der Grosse—die amerikanische Art ist 1%", die englische 4" gross—folgende Verschiedenheiten: 1) die amerikanische Art ist schiefer, die hintere Seite, welche die beiden Falten tragt, kurzer; 2) dieselbe hat keine vertiefte Lunula, und ist namentlich der Schlossrand vorn nicht gerade oderselbst concav, sondern von Anbeginn an convex; dagegen geht 3) eine breite seichte Furche nach dem vordern Winkel hin, von der die englische Art keine Spur zeigt. Ich schlage vor, die amerikanische Art L. Gouldii zu nennen. Sie gehort ubrigens in das Sowerby’sche Genus Axinus, welches mit dem Turton’schen Genus Cryptodon identisch ist, so wie mit dem von mir aufgestellten Genus Plychina”. Holotype.—Presumed missing (Hertlein and Grant, 1972, p. 256). Type locality.-—It inhabits deep water and is very frequently taken from codfish, caught in Massachusetts Bay. Supplementary description—“Shell small, globular, posterior side angulated or furrowed; umbones much recurved; surface sculptured with fine incremental lines; lunule indistinct, depressed in front of beaks; liga- ment external, placed in a groove on the hinge-line and outside the hinge— plate; teeth wanting.” (Arnold, 1903, p. 135) Comparison.—“Binney stated that Philippi’s criteria for separating T. gouldii from the European T. flexuosa are valid, namely, ‘ours is much smaller, more oblique, the hinder end on which the folds are situated is shorter, the lunule is less deep, and the anterior margin is not con— cave, but rather convex. Indeed the disparity in size is so great as scarcely to suggest a comparison.”’ (Hertlein and Grant, 1972, p. 256) Geographic range—Living: Bering Strait, Alaska, to San Diego, Calif. and Atlantic coast; fossil: southern California. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Geologic range—Pliocene to Holocene. Occurrence in California—Pliocene: Lomita Marl Member, San Pedro Formation (Woodring and others, 1946) San Diego Formation (Hertlein and Grant, 1972, p. 256), and unnamed sediments on Deadmans Island, San Pedro, Calif. (Arnold, 1906) and at Potrero Canyon, Santa Monica Mountains (Hoots, 1931); Pliocene and Pleistocene: Fernando Forma- tion (Moody, 1916; Waterfall, 1929; Soper and Grant, 1932) and Wildcat Group (B. Roth, written commun., 1979); Pleistocene: Anchor Silt (Rodda, 1957), Timms Point Silt Member, San Pedro Formation (Clark, 1931; Woodring and others, 1946). Habitat—“Valentine considered T. gouldii to be a member of a ‘Lucinoma annulata—Turcica caflea community’ in beds of Pleistocene age in southern California, deposited probably at a depth of 27 to 46 meters (15 to 25 fathoms). A ‘Thyasira gouldii-Neptunea tabulata’ com- munity is said to live in the ‘shallow outer sublittoral, 20—25 fathoms, silt and clay bottom.” (Hertlein and Grant, 1972, p. 257) Subgenus CONCHOCELE Gabb, 1866 Shell irregularly quadrate, very inequilateral; a sharp angular ridge passes from the beaks to the posterior end; lunular margin nearly straight, followed by resilium in long narrow depression; anterior muscle scar broad. Geographic range—North America and North Pacific. Geologic range—Oligocene to Holocene (table 4). Thyasira (Conchocele) folgen' Wagner and Schilling Plate 7, figure 9 Thyasira folgeri Wagner and Schilling, 1923, p. 254, p]. 45, fig. 6. Original description—“Shell small; ovate, the long axis being in the direction of height; convex; beaks prominent; inturned and prosogyrous; equivalve; inequilateral; slightly excavated beneath beaks; ligamental area long and rather broad: anterior dorsal margin straight; posterior dorsal margin slightly convex; ventral edge strongly arcuate; shell covered by incremental lines; a marked groove or depression extends from the posterior portion of the ventral edge causing the posterior edge to be subtruncate; angle between dorsal margins approximately 100 degrees; hinge unknown. Dimensions: length, 19 mm.; height, 21 mm.; convexity 13 mm.” Holotype.—UCMP 11434. Type locality.—UC 3195. Kern County, Calif. San Emigdio Forma— tion, Eocene. Comparison.—“Thyasirafolgeri approaches most closely to T. bisecla Conrad, a recent species which is reported from the Oligocene of Washington, but is much more ovate in outline, the ventral edge being more evenly rounded and the extremities being much less angulated. The posterior groove is not so sharp. None has been found which ap- proach the size of T. bisecta.” (Wagner and Schilling, 1923, p. 254) Geographic range—Southern California. Geologic range—Eocene and Oligocene. Occurrence in California—Eocene: San Emigdio Formation (Wagner and Schilling, 1923; DeLise, 1967), Eocene and Oligocene: San Lorenzo Formation (Barbat and von Estorff, 1933); Oligocene: Tumey(?) For— mation (Atwill, 1935). Thyasira (Conchocele) disjuncta (Gabb) Plate 7, figures 19,22 Conchocele disjuncta Gabb, 1866, p. 28; 1869, p. 99, pl. 7, figs. 48a, 48b. Tegland, 1928, p. 129. Waterfall, 1929, p. 78. Kanno, 1971, p. 61—62, pl. 7, fig. 3. Thyasira disjuncta (Gabb). Stewart, 1930, p. 194—195, pl. 15, fig. 1. Tegland, 1933, p. 114, pl. 7, figs. 18—22. Woodring and others, 1946, p. 83, pl. 33, fig. 5. Boss, 1967, p. 386—388. Thyasira (Conchocele) disjuncta( abb). Moore, 1984, p. 28, 30, figs. 136, 138, 142. Original description—“Shell ubquadrate; beaks terminal, anterior; anterior end abruptly and angul rly truncated; base broadly rounded; cardinal margin arched, sloping ownwards towards the posterior end. Surface marked only by lines of rowth, except near the posterior part where the peculiar truncation ta es place, the surface suddenly descend- ing at a right angle to the curv of the shell, for a short distance, and then resuming its former direc ion.” Holotype.—MCZ 15017. Type locality—Deadman’s Is and, Los Angeles County, Calif. San Pedro Formation, Pliocene and Pleistocene. Comparison—“As pointed out by Woodring (in Woodring and others, 1946, p. 83), T. disjuncta is larg r and more quadrate and has a more abruptly truncated anterior end than T. bisecta.” (Moore, 1963, p. 72) Comments.—Thyasira disjunct has been identified as Thyasira bisecta (Conrad), a Miocene species from he Astoria Formation, Oregon (Moore, 1963, p. 72, pl. 23, figs. 8, 14, 15), by some paleontologists (Arnold, 1903; Dall, 1901, 1909; Oldroyd, 1924 ; and Grant and Gale, 1931). Tegland (1928) first noted the shell chara ters that separate the two species, and Bernard (1972) has documente the anatomical differences. Krish- tofovich (1936, p. 58—59) also dis ussed the differences between the two species. Thyasira bisecta is illust ‘ated for comparison (pl. 7, figs. 23, 24). Geographic range—Living: aska to Oregon; Spitzbergen (Hagg, 1925) and Gulf of Darien, Colo bia (Boss, 1967); fossil: Washington, Oregon, and southern Californi Geologic range—Oligocene t0 Holocene. Occurrence in California— liocene and Pleistocene: Fernando Formation (Waterfall, 1929; J .D Mount, written commun., 1971), Pico Formation (Waterfall, 1929) Sa Pedro Formation (Gabb, 1866) and Wildcat Group (Ogle, 1953; . Roth, written commun., 1979); Pleistocene: Timms Point Silt Me ber, San Pedro Formation (W oodring and others, 1946). Habitat.—At depths of 100 to 750 m and at temperatures between 0 and 7 °C (Bernard, 1983). Genus ADONT RHINA Berry, 1947 Small, resembling Axinopsida but hinge teeth replaced by indefinite ridges and denticles on somew t reflected lunular and escutcheonal margins. Anterior pseudocardi als tuberculiform. Geographic range—Living: We tern North America; fossil: California. Geologic range—Miocene to flocene. Adontorhina clia Berry, 1947 Plate 11, figures 13, 16 Adontorhina cyclia Berry, 1947, I . 260—261, pl. 1, figs. 1, 2. Jones, 1965, p. 127—141, fig. 1. Scott, 1986, p. 153—155, figs. 1A, 9B, 6—11. Original description.—“Shell thin, inflated, of simple orbiculoid outline, with anteriorly curved beaks; in general recalling Cryptodon, but eden- tulous, the hinge comprising tw granulated or ridged plates, the one immediately anterior to the beak, the other considerably posterior, these being connected by a sharp, narrow ridge, which continues smoothly from the posterior plate, but overlies the posterior terminus of the anterior plate; pallial sinus simple. “The name is derived from the Gr. prefix a-, without, + dons, tooth, +rhine, rasp, file, and has reference to the peculiar roughened hinge plate. “For the present this odd little bivalve is tentatively referred to the family Thyasiridae.” Holotype.—CAS 61460. Type locality—Hilltop Quarry, San Pedro, Los Angeles County, Calif. (33°45.3'N, 118°18.3’W) (Scott, 1986, p. 155) Pleistocene. LERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D25 Supplementary description—“It [A. cyclia] occurs in association with a Thyasira (aff. barbarensis Dall) and Axinopsis serricata (Carpenter, 1864) and appears quite similar to immature shells of the latter until put under the microscope, when the lack of a cardinal tooth and other characteristic differences in the hinge, as well as the different forma— tion of the lunular region become at once clearly apparent. From the Thyasira it is distinguished by its lack of a posterior plication and the strange roughened hinge plates." (Berry, 1947) ”Specimens of A. cyclia can vary from having a narrow, obscure anterior [hinge] plate***to a moderately wide, thickened anterior plate*** *In all specimens of Adontorhina I have observed, no two hinge plates exhibited the same granular pattern. The unique qualities of the hinge granules of each specimen is indeed very reminiscent of the in- dividual variations in human fingerprints.” (Scott, 1986, p. 155) Geographic range—Living: Bering Sea, Alaska to Isla Guadalupe, Baja California Norte; fossil: southern California. Geologic range—Miocene to Holocene. Occurrence in California—Miocene and Pliocene: Capistrano Forma- tion (Kern and Wicander, 1974); Pleistocene: Lomita Marl Member, San Pedro Formation (Berry, 1947), Timms Point Silt (Scott, 1986). Genus AXINOPSIDA Keen and Chavan, 1951 Shell small, discoidal, tumid in the middle, compressed towards the margins; umbones slightly prominent; valves thin, concentrically striate. Geographic range—America, Japan, Mediterranean. Geologic range—Miocene to Holocene (table 4). Habitat—10 to 595 m, chiefly in Arctic and boreal waters but in the Eastern Pacific occurs south to Bahia Todos Santos, Baja California Norte (Hertlein and Grant, 1972, p. 257) Axinopsida serricata (Carpenter) Plate 8, figures 2—4 Cryptodon serricatus Carpenter, 1864b, p. 602. Carpenter, 1865, p. 57. Arinopsis sericatus (Carpenter). Dall, 1901, p. 791, 819, pl. 40, fig. 2. Arinopsida serricata (Carpenter). Palmer, 1958, p. 84—85, pl. 7, figs. 16—18. Hertlein and Grant, 1972, p. 257—258, pl. 44, figs. 17, 18. Original description—“Small, circular, flat; epidermis silken.” Lectotype.—USNM 5249 (Palmer, 1958). Type locality—Puget Sound, Washington. Supplementary description—“Shell small, 5 mm., compressed, len- ticular in shape, higher than long***with curved beaks***."' (Abbott, 1974, p. 464) Geographic range—Living: Aleutian Islands, Alaska to Bahia Todos Santos, Baja California Sur (Abbott, 1974, p. 464), but not cited in Keen (1971); fossil: Alaska to Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in the Californias.—Miocene and Pliocene: Capistrano For- mation (Kern and Wicander, 1974); Pliocene: Lomita Marl Member, San Pedro (Valentine and Mead, 1961), Marquer (Emerson and Hertlein, 1964), and San Diego (Hertlein and Grant, 1972) Formations and un- named strata at Moonstone Beach (B. Roth, written commun., 1979); Pliocene and Pleistocene: Fernando (Willett, 1946) Pico (Addicott and Vedder, 1963), and San Pedro (Valentine and Mead, 1961) Formations. Habitat—4 to 219 m (Hertlein and Grant, 197 2); intertidal to 275 m (Bernard, 1983). Axinopsida viridis (Dall) Plate 11, figures 6, 9 Axinopsis viridis Dall, 1901, p. 819—820, pl. 40, fig. 1. Original description—“Shell small, polished, suborbicular, when fresh covered with a glistening pale-green periostracum, some times exhibiting D26 lighter and darker concentric zones; sculpture solely of fine concentric lines of growth; beaks low, inconspicuous; lunule slightly impressed, but without any bounding sulcus or ridge, small sublanceolate; escutcehon hardly recognizable, very narrow, and inconspicuous. The part of the lunule belonging to the right valve is slightly larger than the other. The ligament is small and very delicate, being not wholly concealed. The subumbonal tooth of the right valve is prominent and strong, the in- flected tooth—like process of the left valve is well developed. Margins of the valves smooth, interior polished, with some obscure radial striae; muscular and pallial impressions normal. In the animal the hepatic glands project in an arborescent manner from each side of the comparatively insignificant bodymass, the gills are normal and rather small. Alt. of shell 6.0, long. 6.2, diam. 3.3 mm. The specimen figured is from Iliuliuk, Alaska, in 19 fathoms, mud.” Holotype.—-None cited by Dall (1901) nor by Bass and others (1968). Type locality—Iliuliuk, Alaska. Comparison—“I have described this shell with some hesitation, as it may prove to be the normally round form of which A. sericata Carpenter is an oblique and ovate variety***The Carpenterian type* * *are higher and more recurved, the periostracum pale yellowish gray and papery.” (Dall, 1901, p. 820) Geographic range—Living: Japan, Alaska to southern California; fossil: southern California. Geologic range—Pliocene to Holocene. Occurrence in California—Pliocene: Foxen Mudstone (W oodring and Bramlette, 1950). Habitat.—3O to 200 m (Bernard, 1983). Family UNGULINIDAE Genus BRUETIA Chavan, 1962 Subtrigonal to subquadrate, somewhat thick; internal radial lines generally well marked. Geographic range—Europe, Central America; California?. Geologic range—Paleocene to Miocene (table 4). Genus BRUETIA? Bruetia? traski (Nelson) Plate 8, figure 5 Diplodonta traski Nelson, 1925, p. 411, pl. 52, fig. 4. Original description—“Shell small, thin, circular, inflated; beak rather prominent, prosogyrous, central. Anterior dorsal edge slightly concave; posterior and ventral edges forming an unbroken circular curve; anterior edge subtruncated, convex. Surface of shell smooth except for fine con— centric growth lines. Length of type specimen, 5 mm; height, 6 mm.; diameter of one valve, about 3 mm.” Holotype.—UCMP 30579. Type locality—UC 3768. Ventura County, Calif. Santa Susana For- mation, Paleocene. Supplementary description.—“Bruetia traski (Nelson)***is quite small, subtrigonal, highly polished, and the medially located umbones are very prominent.” (Zinsmeister, 1983, p. 1287) Comments.—The hinge is not exposed on the holotype of Bruetia? traski so it is tentatively assigned to Bruetia solely on the basis of its outline. Geographic range—Southern California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez (Nelson, 1925) and Santa Susana Formation (Zinsmeister, 1983). PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Genus DIPLODONTA Bronn, 1831 Shell equivalve, not gaping, subcircular, the beaks subcentral and not prominent. Lunule and escutcheon not defined. External surface smooth or incrementally sculptured. Geographic range—Europe, North America, Pacific, West Africa. Geologic range—Paleocene to Holocene (table 4). Subgenus DIPLODONTA Geographic range—Europe, North America, Pacific. Diplodonta (Diplodonta) cretacea (Gabb) Plate 8, figures 1, 6 ?L.[ucina] cretacea Gabb, 1864, p. 177, pl. 30, fig. 255. Not Phacoides cretacea (Gabb) of Arnold, 1907 c, pl. 9, fig. 4. Anderson and Hanna, 1925, p. 168. Diplodonta cretacea (Gabb). Clark and Woodford, 1927, pl. 15, fig. 7. Original description—“Shell thin, flattened, subquadrate; beaks subcentral; ends and base broadly rounded, subtruncate. Surface marked only by fine lines of growth.” Holotype.—Missing (Stewart, 1930). Type locality—From Clayton to Marsh’s, vicinity of Mount Diablo, [Contra Costa County], Calif. Meganos Formation, Paleocene. Comparison—“The moderate convexity and closely spaced, almost microscopic, concentric sculpture make it easy to distinguish this cir- cular variant from Diplodonta polita (Gabb), a very tumid form with comparatively wide spaced ribs****” (Clark and Woodford, 1927) Geographic range—Middle and southern California. Geologic range—Paleocene and Eocene. Occurrence in California-Paleocene: Meganos Formation (Clark, 1921; Clark and Vokes, 1936; Berkland, 1973); Eocene: Tejon Forma- tion (Arnold, 1906). Diplodonta (Diplodonta) polita (Gabb) Plate 8, figure 8 ?Mysia polita Gabb, 1864, p. 178, 233, pl. 30, fig. 256. Gabb, 1869, p. 244. Diplodonta polita (Gabb). Dickerson, 1916, p. 430, 445. Anderson and Hanna, 1925, p. 170—171. Taras(?) politus (Gabb). Vokes, 1939, p. 74, pl. 10, fig. 6. Not “Mysia?” polita Gabb. Stewart, 1930, p. 193, pl. 7, fig. 6. Original description—“Shell small, thin, subglobose; beaks between the middle and anterior end; base and sides form about three-fourths of a nearly perfect circle; anterior end slightly excavated, immediately under the beaks; cardinal margin variable, arched, or sometimes nearly straight. Surface polished and marked by faint concentric lines of growth.” Holotype.—UCMP 11990. Type locality—Not rare about Martinez; and also found at Clayton, near the coal mines (from Division B.). Contra Costa County, Calif. Martinez Formation, Paleocene. Geographic range—Middle and southern California. Geologic range—Paleocene and Eocene. Occurrence in California—Paleocene: Martinez Formation (Stewart, 1930); Eocene: Avenal Sandstone (Vokes, 1939), Domengine (Stewart, 1930; Vokes, 1939), and La Jolla (Vokes, 1939), Ragged Valley Shale Member, Arroyo Hondo (Vokes, 1939) Formations. Diplodonta (Diplodonta) unisulcatus (Vokes) Plate 7, figures 15, 17 Taras unisulcatus Vokes, 1939, p. 74, pl. 10, figs. 4, 7, 10. Diplodonta unisulcatus (Vokes). Givens, 1974, p. 46. iTERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE l Original description—“Shel l small, thin, moderately inflated; umbos prominent, slightly anterior; p sterior dorsal margin slightly convex; posterior margin straight or slightly concave, the ventral anterior and anterior dorsal margins broadly rounded; a distinct posterior groove extending from the umbo to the center of the posterior margin; sur- face ornamented by fine, micr scopic incremental lines; nymph-plates narrow, elongate; both cardin 1 teeth of right valve of hinge oblique, the posterior deeply bifid; posterior cardinal of the left valve oblique, the anterior bifid, straight." l IYohwypes—IJCDJP 15636. 1 Type locality—UC 672. Fre 0 County, Calif. Domengine Formation, Eocene. ‘ Comparison.—“Taras unisulcatus may be distinguished from all other described species in the presence of the posterior groove. It is more in- flated than T. cretaceus (Gab ) and less so than “Mysia” polita Gabb, and may be distinguished fr In both species by the presence of the straight posterior margin as well as the posterior groove.” (Vokes, 1939, p. 74) l Geographic range—Middle land southern California. Geologic range—Eocene. Occurrence in California.— ocene: Avenal (Vokes, 1939) Domengine (Vokes, 1939), and Juncal (Givens, 1974) and Ragged Valley Shale Member, Arroyo Hondo (Vol‘tes, 1939) Formations. Diplodonta (Diplodonta) stephensoni Clark Pl‘hte 8, figure 7 Diplodonta stephensoni Clark, 1918, p. 139, pl. 12, fig. 6. Original description—“Sh ll subcircular, medium in size, only moder- ately inflated; beaks nearly entral, rather inconspicuous; height and length about equal. Posterior orsal edge straight; about equal to anterior dorsal edge which is straightlto slightly convex. Posterior end broadly subtruncate; anterior end vdry broadly rounded. Ventral edge gently and regularly arcuate. Surfac smooth except for medium fine incremen— tal lines of growth. Nymph pl tes heavy, fairly high with no well—defined resilifer pit. In the right valve; the posterior cardinal and in the left valve the anterior cardinal is so deeply bifid that each has the appearance of being two distinct teeth instead of one.” Holotype.—UCMP 11171. J Type locality.—UC 1131. pontra Costa County, Calif. San Ramon Sandstone, Miocene(?). \ Comparison.—“Diplodontal stephensoni somewhat resembles in outline D. serricata Reeve, ** *the t o are only slightly different in outline; the beaks of the latter are possi 1y more conspicuous and the shell slightly more inflated. The chief difference between the two is the hinge plate. D. serricata has a well-defined resilifer pit while D. stephensoni has not; on the latter species the nymph plates are heavier and better defined; also the posterior tooth of e right valve and the anterior of the left valve of the latter species a e more deeply bifid than on the former.” (Clark, 1918, p. 139) 1 Geographic range—Middle California. Geologic range—Miocene ?). Occurrence in CaliforniaTMioceneO): San Ramon Sandstone (Clark, 1918) l Diplodonta (Diplodontd) buwaldana Anderson and Martin Plate 8, figures 9, 10 l Diplodonta buwaldana Anderson and Martin, 1914, p. 56—57, pl. 3, figs. 1a, 1b. Loel and Corey,\1932, p. 212, pl. 36, fig. 10. Adegoke, 1969, p.112. Taras buwaldanus (Anders n and Martin). Grant and Gale, 1931, p. 294. Original description.—“ hell small, thick, subcircular in outline, in- flated; valves equal, inequilateral, slightly elevated in front of the beaks; beaks prominent, elevated, turned forward, slightly anterior to the D27 center; umbones full and broad; lunule indistinct; hinge line broadly arched; dorsal margins nearly straight in some specimens, slightly rounded in others; extremities well rounded, the posterior usually more broadly rounded than the anterior; basal margin circular; surface polished, marked by numerous fine concentric lines of growth; two teeth in each valve, the right posterior tooth faintly bifid; muscular impres- sions inaccessible.” Holotype.—CAS 111. Type locality—0n west bank of a small canyon 1% miles [2.0 km] northeast of Barker’s ranch house, Kern County, Calif. Round Moun- tain Silt (Keen and Bentson, 1944), Miocene. Supplementary description—“The shell outline is variable, ranging from a generally sub-oval shape to those that are nearly trigonal in the umbonal area. Some characteristic features not included by Anderson and Martin (1914, p. 56—57) in the original description are the presence of a small elliptical-shaped resilium just posterior to and below the beak on the right valve; a deep, short, gently curved ligamental groove, a very short elevated nymph and a small ligamental area.” (Takeo Susuki, written commun., 1981). Comparison—“This species differs from Diplodonta parilis Conrad and D. harfordi Anderson by its inflated valves, much more prominent umbones, and more elevated beaks.” (Anderson and Martin, 1914). The dorsal margin on D. buwaldanus is more convex behind the beak than on D. orbellus. (Grant and Gale, 1931, p. 294). Geographic range—Middle California to Baja California Norte. Geologic range—Oligocene to Pleistocene. Occurrence in California-Oligocene and Miocene: Temblor (Eaton and others, 1941; Adegoke, 1969) and Vaqueros (Loel and Corey, 1932; Eaton and others, 1941) Formations; Miocene: Cierbo and Neroly Sand- stones, San Pablo Group (Hall, 1960), Round Mountain Silt (Keen, 1943), and Topanga Formation (Takeo Suzuki, written commun., 1981); Miocene and Pliocene: Etchegoin Formation (Clark, 1915); Pliocene and Pleistocene: San Pedro Formation (Arnold, 1903); Pleistocene: unnamed sediments in southern California (Kanakoff and Emerson, 1959) and in Baja California (Jordan, 1924; Valentine, 1957). Diplodonta (Diplodonta) orbella (Gould) Plate 8, figures 12-15 Lucina orbella Gould, 1851, p. 90. Gould, 1853, p. 395, pl. 15, fig. 3. Diplodonta orbella (Gould). Arnold, 1903, p. 134, pl. 18, figs. 8, 8a. Clark, 1915, pl. 62, fig. 6. Oldroyd, 1924a, pl. 6, figs. 5, 6. Taras orbellus (Gould). Grant and Gale, 1931, p. 293, pl. 14, figs. 14a, 14b. Diplodonta (Diplodonta) orbella Gould. Hertlein and Grant, 1972, p. 252—253, pl. 55, fig. 11; p]. 57, figs. 9, 18. Original description—“T. parva, tenuicula, subglobosa, albida, con- centrice inequiliter striata; aphicibus medianis, haud eminentibus, absque lunula antica; later-ibus fere symmetricis; intus alba. Cardo valvae dextrae dentibus duobus quorum antico minore—valvae sinistrae dentibus duobus quorum antico bifido, postico perobliquo, instructus; denibus lateralibus nullis; cicatricibus leviter impressis, palleali serie punctorum composite. Long. 4/5; alt. 6/8; lat. 1/2—5/8 poll. “Shell small, rather thin, subglobose, dingy white, marked with delicate lines of growth, which at some parts are more conspicuous than at others, and render the surface somewhat irregular; beaks very nearly median, not prominent; no distinct lunule in front of them; ligament prominent; extremities a little above the middle of altitude, very nearly symmetrical. Interior white. Hinge with two direct teeth in the right valve, of which the anterior is smallest, and the posterior is bifid; and two in the left valve, of which the anterior is bifid and the posterior very oblique; lateral teeth none; muscular impressions faint, very large; pallial impression indistinct, composed of a series of polished dots.” Holotype.—MCZ 169271. Type locality—San Diego. San Diego County, Calif. Holocene. D28 Supplementary description—“This is a rather small, subglobose shell with median, inconspicuous beaks and fine growth lines.” (Grant and Gale, 1931) “Shell to about 30 mm in diameter, nearly spherical, with concentric growth lines***”. (Haderlie and Abbott, 1980, p. 370) “In Diplodonta orbellus the cardinal bifid in the left valve is directly below the beak and projects hook—like. The posterior blade—like cardinal is almost parallel to the ligamental nymph or shield. In the right valve the root of the bifid cardinal is posterior to the beaks and slants posteriorly. The anterior cardinal is peg-like and under the beak**** There are no lateral teeth. “The ligament is mostly external. It is largely posterior to the beaks, usually terminating at the umbo but occasionally projecting slightly beyond. Interiorly, the posterior dorsal margin folds over behind the ligament which rests in a groove attached to and behind a calcareous shield****0ften this shield is broken when the valves are separated making identification difficult.” (Hertz and others, 1982) Comparison.—“Diplodonta impolita differs from D. orbella in the nar— rower, less inflated and more pointed umbos, more steeply sloping anterior dorsal margin, earthy texture and coarser incremental striae. Also the right anterior cardinal is vertically elongated in comparison to the analogous somewhat node-like tooth on Gould’s species.” (Hertlein and Grant, 1972, p. 253) “Luciua approximata and L. tenuisculpta Carpenter, which somewhat resemble this species, are finely sculptured. “The shell of Diplodonta subquadrata Carpenter is much more com- pressed than D. orbella and is somewhat thinner.” (Jordan, 1936, p. 128) Comments—The hypotype (UCMP 11521) of Clark (1915, pl. 62, fig. 6) is a moderately well preserved right valve, that is inflated and has concentric lamellae preserved on portions of the shell. Geographic range—Living: middle California to Mexico; fossil: middle California to Baja California Sur. Geologic range—Oligocene to Holocene. Occurrence in the Californias.—Oligocene and Miocene: Temblor For- mation (Adegoke, 1969) and Vaqueros(‘l) Formation (Loel and Corey, 1932); Miocene: Neroly Sandstone, San Pablo Group (Clark, 1915) and San Pablo Formation (Clark, 1915); Miocene and Pliocene: Etchegoin Formation (Clark, 1915); Pliocene: San Diego Formation (Hertlein and Grant, 1972); Pliocene and Pleistocene: Fernando (Eldridge and Arnold, 1907), Merced (Hertlein and Grant, 1972), Pico (Hertlein and Grant, 1972), and San Pedro (T.S. Oldroyd, 1924) Formations; Pleistocene: Timms Point Silt Member, San Pedro Formation (Clark, 1931), and un- named strata in southern California (Valentine, 1956, 1960b; Kanakoff and Emerson, 1959, Vedder and Norris, 1963), in northwestern Baja California Norte (Valentine and Rowland, 1969), at Bahia Magdalena (Jordan, 1936), at Bahia T6rtola (Emerson and others, 1981), and at Bahia Tortola (Chace, 1956; Emerson, 1980), Baja California Sur. Habitat—Commonly nestling in holes in rocks; sometimes builds a “nest” with a protective covering of sand and mucus, intertidal to 40 m (Hertlein and Grant, 1972, p. 252). Intertidal to 55 m (Bernard, 1983). Diplodonta (Diplodonta) subquadrata Carpenter Plate 8, figures 16—20 Diplodonta subquadrata Carpenter, 1856, p. 230—231. Dall, 1921, p. 34. Taras subquadratus (Carpenter). Hertlein and Strong, 1947, p. 130. Durham, 1950, p. 78, pl. 19, fig. 4. Diplodonta subquadrata (Carpenter). Keen, 1971, p. 128, fig. 292. Original descriptim.—“D. t. subquadrata, valde inaequilaterali, antice brevi; tenui, albo-flavescente, epidermide tenuissima; striis incrementi exillimis, ligamento subexterno; dentibus cardinalibus parvis; lateralibus antico in utraque valve acuto, postico subobsoleto; cicatricibus muscu< laribus, antica a cardine remota, elongata, intus crenulata; postica irregulariter pyriformi; linea pallii margini appropinquante.” PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Syntypes.—BM(NH) 196384. Two syntypes (Keen, 1968, p. 434). Type locality—Mazatlan, Mexico. Holocene. Supplementary description—“In shape like Lucinopsis undulata; remarkable for the anterior lateral teeth.” (Carpenter, 1856) Geographic range—Living: Baja California Sur to Galapagos Islands; fossil: Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in Baja California Sur.—Miocene:Comond1’1 Formation (Durham, 1950); Pleistocene: unnamed sediments on Islas Coronados and at Bahia Santa Inez (Durham, 1950) and Isla Carmen (Hertlein, 1957) Habitat—On mud flats and offshore to depths of 137 m (Keen, 1971); intertidal to 140 m (Bernard, 1983). Subgenus ZEMYSINA Finlay, 1927 Very convex; hinge with longer and more bifid teeth and more elongate muscle scar than in Diplodonta s. 3. Geographic range—Europe, North America, Pacific. Geologic range—Paleocene to Holocene (table 4). Diplodonta (Zemysina) pacified Zinsmeister Plate 8, figures 22—24 Diplodonta(Zemysina)pacifica Zinsmeister, 1983, p. 1287, figs. 10, D. Original description—“Shell medium-sized, highly inflated, subcir- cular; beaks small, prosogyral, umbones subcentral; slight angulation at the intersection of hinge line with posterior and anterior margins; ventral margin broadly rounded; escutcheon very narrow; surface smooth with very weakly developed concentric growth increments.” Hololype.—UCR 6682/100. Type locality—UCR 6682. Ventura County, Calif. Simi Conglomerate, Paleocene(?). Comparison—“D. (Z.) pacifica n. sp. can easily be separated from all other Paleocene lucinids from the West Coast by its highly inflated valves, nearly smooth surface, and the absence of a lunule. Bruetia trashi (Nelson), the only species of the Ungulinidae reported from the Paleocene of the Simi Hills, is quite small, subtrigonal, highly polished, and the medially located umbones are very prominent.” (Zinsmeister, 1983, p. 1287) Comments—Although the hinge is not exposed on the holotype of Diplodonta (Zemysina) pacifica, it agrees well in outline with the subgenus Zemysina. As noted by Zinsmeister (1983, p. 1287) this is the first Paleocene record of the Australian subgenus in the eastern Pacific, although it lives in tropical North America (Keen, 1971, p. 128). Geographic range—Southern California. Geologic range.—Paleocene(?). Occurrence in California.—Paleocene(?): Simi Conglomerate. Genus FELANIELLA Ball, 1899 Shell small, very inequilateral, slightly inflated; sculpture consisting of incrementals; ligament external. The shells of this genus differ from those of Diplodonta s. s. in that they are more compressed and less equilateral. Geographic range—North America, western Pacific, Europe, Africa. Geologic range—Cretaceous to Holocene (table 4). Subgenus FELANIELLA Geographic range—North America, Pacific, Europe. Geologic range—Paleocene to Holocene. ‘LI‘ERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE l Felaniella (Felam'dlla) harfordi (Anderson) rm: 8, figures 21, 25—29 Diplodonta harfordi Anderson, 11905, p. 197, pl. 17, figs. 88, 89. Arnold, 1909, pl. 39, fig. 6. Loel anld Corey, 1932, p. 212, pl. 36, figs. 11a, 11b. Adegoke, 1969, p. 112. Taras harfordi (Anderson). Grant and Gale, 1931, p. 293. Felaniella harfordi (Anderson). Addicott, 1973, p. 29, pl. 4, figs. 2, 7. Original description—“Shell not large, rotund, sub-quadrate in outline; beaks nearly central,‘ low, closely approaching each other; cardinal margin straight, excavated; anterior margin sometimes a little produced, but generally rounded; surface marked only by concentric lines.” l Syntypes.—CAS 62, 63. l Type locality—Three miles [4.8 km] west of Coalinga [NW 1/4, sec. 34 T. 20 S., R. 14 E]. Fresno County, Calif. Temblor Formation, Oligocene and Miocene. Supplementary description.l—“This Diplodonta is recognized by its thinness and subquadrate outlihe, the form found in the Vaqueros being even more quadrate and thinnei‘ than the described Temblor form.” (Loel and Corey, 1932, p. 212). l “The valves of Felaniella hail ordi“ * *are somewhat variable in outline and are only slightly inflated. enerally, they are subquadrangular and have a distinctly flattened lsegment posteriorly***assignment to Felaniella is indicated by the tharacteristic inequilateral profile of the valves and the prominent be ks.” (Addicott, 1973, p. 29) “D.[iplodonta] harfordi is e sily recognized by its characteristic sub- quadrangular outline with a lightly extended anterior portion and a widely expanded posterior ve tral margin. The posterior dorsal edge is inclined in a straight line fro the beak to the gently curved posterior. The anterior dorsal margin i gently concave from the beak and then becomes convex to the exte+ded anterior.” (Takeo Susuki, written commun., 1981) Comparison—“This species) [Felaniella harfordi] appears to be very closely related to orbellus, bug can be distinguished by its more project— ing, less twisted beaks, and b the fact that orbellus is usually more in» flated, especially in the northTern variety aleuticus (Dall).” (Grant and Gale, 1931, p. 293) Geographic range—Middle and southern California. Geologic range—Oligocene‘ to Pliocene. Occurrence in California.‘—Oligocene: so-called Phacoides Sand (Addicott, 1972) and Wygalw Sandstone Members (Addicott, 1973), Temblor Formation; Oligocer'if and Miocene: Temblor (Woodford, 1925; Grant and Gale, 1931; Adeg ke, 1969; Addicott, 1973) and Vaqueros (Loel and Corey, 1932; Eato and others, 1941) Formations; Miocene: Santa Margarita (Anderson, 1905; Grant and Gale, 1931; Preston, 1931; Adegoke, 1969) and Topan a (Kew, 1924; Takeo Suzuki, written commun., 1981) Formations; Miocene and Pliocene: Etchegoin Forma- tion (Arnold, 1909; Adegoke‘, 1969). l Felam'ella (Felpniella) parilis (Conrad) Plate 8, figure 11 Loripes parilis Conrad, 184 , p. 432, fig. 7. Diplodonta (Felaniella) pari is (Conrad). Dall, 1909, p. 117, pl. 11, fig. 6. Etherington, 1931, p. ‘ 6, pl. 5, figs. 4, 6. Moore, 1963, p. 71, pl. 23, figs. 6, 9. ‘ Diplodonta parilis (Conrad) Clark, 1915, p. 418. Nomland, 1917a, p. 219. Adegoke, 1969, p. 12. Taras parilis (Conrad). Gra t and Gale, 1931, p. 294. Original description.—“ entiform, inequilateral, not ventricose; length and height equal, summit slightly prominent; margins very regularly rounded.” ‘ Holotype.—ANSP 4546. ‘ D29 Type locality—Astoria, Clatsop County, Oreg. Astoria Formation, Miocene. Supplementary description—“The holotype of Diplodonta parilis is an immature right valve; the apex of the beak is broken and the hinge is not exposed****The type is thin shelled and has concentric grooves and ridges, irregularly spaced. The hinge line forms an abrupt angle of about 35° with the beak, posteriorly and anteriorly. The shell is almost perfectly circular in outline, if the angulation of the hinge is ignored.” (Moore, 1963) “D. parilis“ * *is easily distinguished from the other species of diplodon» tids by its nearly circular outline; an inconspicuous umbo; valves com- pressed to slightly inflated; a nymph that is short and traverses the hinge in a horizontal direction rather than paralleling the dorsal margin.” (Takeo Susuki, written commun., 1981) Geographic range.—Alaska(?); Washington to southern California. Geologic range—Oligocene to Pliocene. Occurrence in Calyfornia.—Oligocene: Tumey Formation (Atwill, 1935); Oligocene and Miocene: Vaqueros Formation (Loel and Corey, 1932); Miocene: Cierbo (Hall, 1980) and Neroly Sandstones (Clark, 1915; Hall, 1960), San Pablo Group, McLure Shale Member, Monterey (Adegoke, 1969), Santa Margarita (Adegoke, 1969) and Topanga (Takeo Susuki, written commun., 1981) Formations; Miocene and Pliocene: Etchegoin Formation (Arnold, 1909; Nomland, 1917a); Pliocene: Niguel Formation (Vedder, 1960, 1970). Felaniella (Felam'ella) cornea (Reeve) Plate 9, figures 1—3; plate 10, figure 11 Lucina cornea Reeve, 1850, [Lucina] pl. 9, fig. 25. Lucina nitens Reeve, 1850, pl. 9, fig. 50. Lueina sericata Reeve, 1850, pl. 9, fig. 55. Taras parilis (Conrad) variety sericatus (Reeve). Grant and Gale, 1931, p. 295, pl. 14, figs. 12a, 12b. Diplodonta sericata (Reeve). Arnold, 1903, p. 134, pl. 18, figs. 5, 5a. Jordan, 1936, p. 128. Woodring and others, 1946, p. 83, pl. 36, figs. 11-14. Taras (Felaniella) sericatus Reeve. Hertlein and Strong, 1947, p. 131, pl. 1, fig. 10. Taras sericatus (Reeve). Durham, 1950, p. 78, pl. 19, figs. 1, 18. Felaniella (Zemysia) sericata (Reeve). Keen, 1971, p. 128—129, fig. 295. Diplodonta (Felaniella) cornea Reeve. Hertlein and Grant, 1972, p. 253—254, pl. 43, figs. 7, 13, 20. Original description—“Shell Cardium-shaped, a little higher than long, rather depressed, no lunule, concentrically impressly striated, hinge with two central teeth in each valve, one of which is bifid; whitish, covered with a light olive shining horny epidermis.” Syntypes.—BM(NH) 1963 130/1—2. Type locality—“flab. Gulf of Nicoiya (in coarse sand at a depth of from ten to thirteen fathoms)”, Costa Rica. Holocene. Supplementary description—“The first of a small group included in this plate, all having a bifid tooth nearly similar to that of Diplodonta, but more especially characterized by the presence of a shining horny epidermis.” (Reeve, 1850) “This species is generally recorded under the name Diplodonta sericata Reeve. Hertlein and Strong pointed out that D. cornea has page prior— ity and this nomenclature was also adopted by Olsson. Furthermore D. sericata was originally described without information as to the locality from which it came. Later Adams and Reeve cited it from the Philip- pine Islands. Finally Carpenter and Dall considered it to be a west American species. After consideration of the history of this species, we conclude that it is best to use the earliest name applicable to this form.” (Hertlein and Grant, 1972, p. 254) Comparison.—Diplodonta parilis (Conrad) is slightly more elongated anteriorly—posteriorly and the ends are a little more flattened than those D30 of D. cornea. Diplodonta harfordi Anderson has a straighter anterior dorsal margin. (Hertlein and Grant, 1972, p. 254). Geographic range—Living: Southern California to Peru; fossil: Southern California to Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in the Californias.—Pliocene: San Marcos (Durham, 1950) and San Diego (Hertlein and Grant, 1972) Formations; Pliocene and Pleistocene: Fernando (J. Mount, written c0mmun., 1971) and Saugus (Waterfall, 1929) Formations; Pleistocene: unnamed strata of southern California and Baja California Sur (Jordan, 1936; Kanakoff and Emer— son, 1959; Emerson and Hertlein, 1964) and Bahia Tértola (Emerson, 1980) Habitat—7 to 73 m (Hertlein and Grant, 1972, p. 254). Family CHAMIDAE Genus CHAMA Linné, 1758 Shell thick, attached by left valve throughout life; concentric sculpture of distinctive flattened spines in irregular radial rows. Geographic range—Europe, North America, southwestern Pacific. Geologic range.—Cretaceous(?); Paleocene t0 Holocene (table 5). Habitat—Adapted to waters with little suspended material and unable to withstand lowered salinity. Nearshore inhabitants of rocky shores and coral reef communities. The greatest number of species are cemented to massive rocks in exposed areas from the midtidal zone to a depth of a few meters, and the species are all large and thick shelled. The smaller, thin-shelled species live in fissures, crannies, on the underside of boulders, and, at depths of 20 or more meters, cemented to pebbles, shells, or coral (Bernard, 1976). Subgenus CHAMA Concentric ornamentation of distinctive flattened spines in irregular radial rows. Chama (Chama) echinata Broderip Plate 9, figures 7, 12; Plate 11, figure 15 Chama echinata Broderip, 1835a, p. 150; 1835b, p. 305, pl. 39, figs. 5, 7. Hertlein and Strong, 1946, p. 108—109. Durham, 1950, p. 72—73, pl. 17, figs. 8, 11. Keen, 1971, p. 147, fig. 347. Bernard, 1976, p. 17, figs. 7a—f. Original description—“Chama testa albida purpureo varia, spinis for- nicatis echinata; intus atro-purpurea vel sub—rubra, limbo integro; dente cardinali rubro.” Holotype.—BM(NH). Type locality—“Bab. in America Centrali. (Puerto Potrero).” Supplementary description—“The triangularly inflated, sharply angulated left valve appears to be very characteristic of this species.” (Durham, 1950, p. 73) “Shell small or of medium size, irregular, attached generally broadly by the anterior side of the left Valve. Surface of right valve is covered with close—set, small spines.” (Olsson, 1961, p. 224—225) “The spines of this species, which are close set and well developed in youth, are entirely abraded in age, till nothing but corrugation is left externally.” (Broderip, 1835, p. 305) Comments—The unattached surface of the left valve has small spines. Geographic range—Living: Baja California Sur to Panama; fossil: Baja California Sur. Geologic range—Miocene to Holocene. Occurrence in the Californias.—Miocene: Comondu Formation (Durham, 1950); Pliocene: Marquer Formation (Durham, 1950); Pleisto- cene: unnamed sediments on Isla Tiburon. Habitat—Attached to large rocks from low-intertidal zone to 25 m (Bernard, 1983). PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Chama (Chama) frondosa Broderip Plate 9, figures 8—10; plate 10, figure 7 Chamafrondosa Broderip, 1835a, p. 148; 1835b, p. 302, pl. 38, figs. 1, 2. Jordan and Hertlein, 1926, p. 427, pl. 34, fig. 1. Hanna, 1926, p. 463. Jordan, 1936, p. 127. Grant and Gale, 1931, p. 280. Hertlein and Strong, 1946, p. 109. Durham, 1950, p. 73, pl. 17, figs. 5, 10. Olsson, 1961, p. 225, pl. 34, figs. 1—1b; pl. 86, fig. 2. Keen, 1971, p. 147, fig. 348. Original description—“Chama testa sublobata, lamellosa, lamellis sinuosis frondosis, longitudinaliter plicatis et in utraque valva cardinem versus biseriates, maximis; intus albida, limbo purpu-rascente, crenulato.” Holotype.—BM(NH). Type locality.—“Hab. ad Insulam Platam Columbiae Occidentalis. It was dredged up from a rock of coral, to which it was adhering, at a depth of seventeen fathoms [31 m].” (Broderip, 1835a, p. 148) Supplementary description—“The shell is generally large, coarse, subovate. Outer layer heavy, with strong, concentric lamellae on the surface, generally extended into longitudinally plaited foliations.” (Olsson, 1961, p. 225) “The arrangement of the scales along distinct radiating lines is characteristic of this species.” (Jordan, 1926) “In its typical form this is a rather heavy***shell with long spines like fan-shaped leaves.***Full development of the spines seems more common southward.” (Keen, 1971, p. 147) “This***is the only west American species with foliated spines” (Bernard, 1976, p. 17—18). Comments—The spines are coarsely and unevenly ribbed. Geographic range—Living: Golfo de California to Ecuador and the Galapagos Islands(?); fossil: Southern California to Baja California Sur. Geologic range—Miocene or Pliocene to Holocene. Occurrence in the Californias.—Miocene and Pliocene: Almejas For- mation (Hertlein, 1933; Minch and others, 1976); Miocene or Pliocene: Imperial Formation (Hanna, 1926); Pliocene: Marquer Formation (Durham, 1950); Pleistocene: unnamed sediments south of Punta San Telmo (Durham, 1950) and at Bahia San Quintin (Jordan, 1926), Habitat.—Intertidally on rocks and offshore to depths of a few meters (Keen, 1971). A warm water species (Bernard, 1976). Chama (Chama) arcana Bernard Plate 10, figures 6, 8—10; Plate 11, figures 10, 14, 17—19 Chama arcana Bernard, 1976, p. 14-15, figs. 4a, b. Chama pellucida Broderip. Arnold, 1903, p. 130—131. Arnold, 1909, p. 158, pl. 26, figs. 5, 6. Clark, 1915, p. 417. Packard, 1918, p. 263. Grant and Gale, 1931, p. 279. Woodring and others, 1940, p. 38, pl. 14, figs. 1-4, 10. Hertlein and Strong, 1946, p. 109. Olsson, 1961, p. 225, pl. 33, figs. 2, 2a; pl. 34, fig. 5. Adegoke, 1969, p. 111. Hertlein and Grant, 1972, p. 227, pl. 43, figs. 12, 15. Not Chama pellucida Broderip, 1835a, p. 149; 1835b, p. 302, pl. 38, fig. 3. Original description—“Shell interior porcellaneous, white, exterior waxy translucent. Outline variable, depending upon habitat, either round or dorsoventrally elongated. Cemented to substrate by wide area of left valve. Exterior sculpture often abraded and encrusted, color white, sometimes with streaks of pink or red particularly on posterior of right valve. Sculpture of either valve consisting of close-set foliations irregular- ly joined into thin translucent concentric lamellae, with several radial rows of larger prolongations. Ligament deeply sunk and placed on a substantial nymph. Dental processes not highly developed, nymphal ridge of left valve with a strongly developed longitudinal groove. Shell margins minutely denticulated. Commissural shelf broad, lacking inner layer, sometimes iridescent. Adductor muscle scars large. Pallial line shallow, entire.” Holotype.—LACMP 1723. Type locality—Newport Bay, Orange County, Calif. Holocene. i TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE l Comparison—“The new species can only be confused with C. pellucida Broderip [see pl. 11, figs. 1, 12], but the commissural shelf is wider and the latter lacks the streaks ofl bright color often present on the upper valve. The sculpture of C. arlcana is irregular, thin, and periodically drawn out into longitudinally lstriated lamellae, which are not present in C. pellucida, where the scu pture is more uniform and subdued. The shell of C. pellucida is propor ionately thicker and tends to be antero- posteriorly elongated, while i C. arcana it is subcircular or dorsoven- trally elongated. A distinct, b t small, pallial sinus is present just below the adductor muscle in C. pell do, which is absent in the new species.” (Bernard, 1976, p. 14) Geographic range—Living Oregon to Baja California Sur; fossil: middle California to Baja C ifornia Sur. Geologic range—Miocene to Holocene. Occurrence in the Californi .——Miocene: Castaic Formation (Stanton, 1966), Cierbo and Neroly Sandstones, San Pablo Group (Hall, 1960) San Pablo Formation (Clark, 1915); Miocene and Pliocene: Etchegoin For- mation (Arnold, 1909; Arnoldland Anderson, 1910); Pliocene: upper part of Capistrano (Kern and Wicander, 1974), Niguel (J .G. Vedder, written c0mmun., 1978), lower part bf Pico (W.O. Addicott and J .G. Vedder, written commun, 1968), San lDiego (Hertlein and Grant, 1972), and San Joaquin (Woodring and otliers, 1940; Adegoke, 1969) Formations; Pliocene and Pleistocene: Flarnando (Soper and Grant, 1932; Willett, 1946), Pico (Waterfall, 1929), land San Pedro (Arnold, 1903); Pleistocene: unnamed sediments on San icolas Island (Vedder and Norris, 1963), at Newport, Calif. (Kanakoff and Emerson, 1959), in northwestern Baja California Norte (Valentine, #957), at Bahia San Quintin (Jordan, 1926; Valentine, 1960b), at Bahi Magdalena (Jordan, 1924), Isla Carmen (Durham, 1950), Bahia Sariia Inez, Arroyo de Arce, Bahia Marquer (Durham, 1950), and Bahia ‘ConcepciOn. Habitat—Clear water, oft n in nooks and crannies in exposed zones. Attached to a solid substrat , gravel, usually subtidally. In Oregon and California, from low intertidlal zone to 50 m; in its more southern range to 80 m. l l l Chama (Chama) s uamuligera Pilsbry and Lowe Plate 0, figures 1, 3, 5, 12 Chama squamuligera Pilsbi‘y and Lowe, 1933, p. 103, pl. 14, fig. 10. Hertlein and Strong, 19%, p. 110. Durham, 1950, p. 73, pl. 17, figs. 3, 6. Keen, 1971, p. 149, fig. 351. Bernard, 1976, p. 21, figs. 9c, d. Original description—“A small rounded species attached by the left valve, whitish, with a dens sculpture of small vaulted scales, more or less extensively united into rregularly concentric frills. The right valve is rather strongly convex, 1 ft valve more or less angular. The interior is white, the margin is fring d with scales and internally finely crenulate, or in the thickest specimen the broad edge is granulose. The greatest diameter (height) is 21 In .; often less.” Holotype.—ANSP 15562 . Type locality—San Jua del Sur, Nicaragua. Supplementary descript on.—“This is the smallest West American form. The shells are round d, both valves arched, and the sculpture con- sists of small scales that tend to join into concentric frills. The shell margin is finely crenulate and may even be granulose on fully adult shells, none of which are more tlhan an inch in diameter. About 20 mm in height.” (Keen, 1971, p. 1l49) Comparison—“This little species resembles the young stage of C. echinata Brod., except in clolor and shape. If it were not for the locality ‘Lord Hood Island, PacificlOcean’ we would think our shell was Charna spinosa Brod.” (Pilsbry ahd Lowe, 1933, p. 103) Commts.—The spines n the right valve if present are narrow, long, and closely set. l Geographic range—Livi g: Baja California Norte to Galapagos Islands; fossil: Baja California Su . Geologic range.—Mioce e to Holocene. D31 Occurrence in Baja California Sun—Miocene: Comondu (Durham, 1950); Pliocene: Marquer Formation (Durham, 1950); Pleistocene: un- named sediments at Islas Coronados, Bahia Santa Inez (Durham, 1950), Isla Carmen (Hertlein, 1957). Habitat—Intertidal to 13 m (Keen, 1971). Many are found nestling in dead bivalve shells or on small pebbles from the subtidal zone to 20 m (Bernard, 1976). Subgenus CHAMA? Chama (Chama?) sp. Plate 9, figures 4, 5 Chama, n. sp.‘.7 Loel and Corey, 1932, p. 209, pl. 36, figs. 1a, 1b. Comments.—This is the oldest known record of Chama in California. Loel and Corey had three specimens, all poorly preserved with most of the shell missing. Loel and Corey described one specimen, from UC locality A 335, as having part of the shell bearing many irregular, sharp lamellae. On the basis of the specimens available, all that can be said is that Chama was present in the Vaqueros Formation. Geographic range—Southern California. Geologic range—Oligocene and Miocene. Occurrence in California—Oligocene and Miocene: Vaqueros Forma- tion (Loel and Corey, 1932). Genus ARCINELLA Schumacher, 1817 Shell nearly equivalve, briefly attached by right valve in early growth stages only. Sculpture of radial rows of long, partially recurved spines, interspaces pitted. Geographic range—Southeastern and southwestern U.S., Central and South America. Geologic range—Miocene to Holocene (table 5). Arcinella californica (Dall) Plate 10, figure 13 Echinochama californica Dall, 1903a, p. 950, pl. 62, fig. 5. Dall, 1903b, p. 1404. Hanna, G D., 1926, p. 465. Arcinella californica (Dall). Keen, 1971, p. 149. Original description.—“Echinochama californica Dall, new species, from off Cerros Island, Lower California, in 25 fathoms; length exclusive of spines, 40 mm.; U.S.N.M., No. 96452. The coloration is yellowish white.” Holotype.—USNM 96452. Type locality—Isla Cedros, Baja California Norte. Holocene. Supplementary description—“The regular form and the symmetrical rows of long spines make this easy to recognize.” (Keen, 1971, p. 149) Comparison—“E. californica Dall** *differs from E. arcinella by its flatter, larger, and more quadrate valves, less prominent beaks, less impressed lunule, more numerous ribs and longer spines***” (Dall, 1903b, p. 1404) “This [A. californica] rare species is closely related to the Caribbean A. arcinella (Linné, 1767) but may be distinguished by the more pro- duced anterior lobe, longer spines and more distinct surface pattern.” (Bernard, 1976, p. 24) Geographic range—Living: Baja California N orte to Panama; fossil: southern California. Geologic range—Miocene or Pliocene. Occurrence in California—Miocene or Pliocene: Imperial Formation (G D. Hanna, 1926). Habitat.—22—46 m (Keen, 1971); 25—80 m (Bernard, 1983). Genus PSEUDOCHAMA Odhner, 1917 Shell attached by right valve. Geologic range—Oligocene to Holocene (table 5). D32 Subgenus PSEUDOCHAMA Nepionic shell with concentric sculpture only. Geographic range—Mediterranean, Central America, southwestern Pacific. Geologic range—Oligocene to Holocene. Comments.—Kennedy and others (1970) believe that Pseudochama should not be considered a distinct genus. Pseudochama (Pseudochama) exogyra (Conrad) Plate 9, figures 11, 13, 14; plate 10, figures 2, 4; plate 11, figure 5 Chama exogyra Conrad, 1837, p. 256. Reeve, 1847, pl. 7, fig. 38. Arnold, 1903, p. 130. Pseudochama exogyra (Conrad). Dall, 1921, p. 33. Waterfall, 1929, p. 78. Grant and Gale, 1931, p. 281. Durham, 1950, p. 73—74, pl. 17, figs. 4, 13. Bernard, 1976, p. 26—27, figs. 10d—f Original description—“Shell obliquely affixed, sinistral; lamellae of the valves prominent, deeply lobed; colour white, tinged with red and green; within white, margin entire; posterior muscular impression pro- foundly elongated.” Syntypes.—BM(NH) 1961520155. Type locality.—Santa Barbara, Calif. Holocene. Supplementary description—“Shell of medium size, oval, irregular; left valve subcompressed, thick, attached when living; umbo small, sub- marginal, much twisted, either dextral or sinistral, generally the former; surface foliated with irregular, disconnected, rough, translucent, con- centric frills; hinge-tooth thick in free valve; two teeth in attached valve; adductor impressions large, oblong, the anterior encroaching on the hinge-tooth." (Arnold, 1903, p. 130) Comments.—The specimen figured (pl. 10, figs. 2, 4) from the Pliocene Marquer Formation has very subdued frills near the attached surface; the largest frills are near the ventral edge. Geographic range—Living: Oregon to southern California; fossil: Southern Californa to Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in the Cahfomias—Pliocene: Marquer Formation (Durham, 1950); Pliocene and Pleistocene: Fernando (Eldridge and Arnold, 1907; Moody, 1916; Soper and Grant, 1932; Willett, 1946), Pico (Waterfall, 1929), San Pedro (Arnold, 1903), and Santa Barbara (Dibblee, 1966) Formations; Pleistocene: Timms Point Silt Member, San Pedro Formation (Clark, 1931) and unnamed sediments in southern Califor- nia (Hoots, 1931; Kanakoff and Emerson, 1959), northwestern Baja California Norte (Valentine, 1957), on Islas Coronados (Durham, 1950), and at Bahia T6rtola, Baja California Sur (Chace, 1956). Habitat—20 to 155 m (Bernard, 1983). Common on rocky reefs, usually in large clusters; middle intertidal zone along open coast (Haderlie and Abbott 1980). FOSSIL LOCALITIES [Corrections and information not in the original description are in brackets;feet and miles are converted to the metric system; formations are cited as emended by later workers, where pertinent] Southern Pacific (University): SP 321. [Devil’s Kitchen, 0.4 km above road, San Emigdio Creek], Kern County, Calif. San Emigdio [Formation]. Stanford University [These collections are now all in the California Academy of Sciences]: SU 2121. Near center of SW1/4 sec. 6, T. 29 S., R. 30 E., Caliente quadrangle, Kern County, Calif. Lowermost part of Round Moun- tain Silt. SU 2697. Simi Hills, [4.8 km east-northeast of Simi Peak, near head of E fork of Las Virgenes Canyon], Camulos quadrangle, Ven- tura County, Calif. “Martinez” [Formation]. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA University of California at Berkeley: UC 243. Concord quadrangle. 2.8 km due south of Muir Station, [Contra Costa Co., Calif]. Martinez Group. UC 340. [SE1/4 NE1/4 section 4, T. 1 S., R 1 W., Mt. Diablo quadrangle, Contra Costa Co., Calif]. Martinez [Formation]. UC 672. South part of crest of Parson’s Peak, SW1/4NW1/4 T. 18 S., R. 14 E., Coalinga quadrangle [Joaquin Rocks quadrangle, Fresno County], Calif. Domengine Formation. UC 784. Near Lower Lake, at old brick yard, 0.4 km east of village NW1/4NE1/4 sec. 11, T. 12 N., R. 7 W., Lake County, Calif. Mar— tinez Formation. UC 1131. 0.8 km southwest of town of Walnut Creek; in creek bed about 90 m to E of Oakland and Antioch bridge; elevation 14 m; Contra Costa Co., [Calif], long. 122° 4' 8”, lat. 37° 53' 7”. [San Lorenzo Formation]. UC 1817. Opposite the place where Urruttia Canyon enters Salt Creek, 30 m up fourth small draw from west end of ridge. SW1/4NW1/4 sec. 15, T. 18 S., R. 14 E., Coalinga quadrangle [Joaquin Rocks Quadrangle, Fresno County], California. Cerros Shale Member, Lodo Formation. UC 2226. La Jolla quadrangle, lat. 33° 50'; long. 117° 14’. Rose Canyon, southeast of Soledad Mountain and north of Ladrillo Station on Southern Pacific R.R., San Diego County, Calif. Tejon Group. UC 3159. [SW72 sec. 20, T. 1 N., R. 2 E., Mt. Diablo quadrangle], Contra Costa County, [Calif]. Meganos [Formation]. UC 3195. SE corner sec. 31, T. 10 N., R. 21 W. From small hogback which joins cliff S of Devil’s Kitchen and N of locality, [Kern Co., Calif]. San Emigdio [Formation]. UC 3768. Just south of minor saddle on ridge 2990 m N. 14° E. of Hill 2150, Simi Hills, Calabasas quadrangle, Ventura County, [Calif]. “Martinez” [Formation]. UC A 1297. Sandstone cliff on northeast bank of Pleasants Creek opposite Brink Ranch House about 1 km east of BM. 257, 3 km south of Putah Creek, W1/2 sec. 12, T. 7 N., R. 2 W., Napa quadrangle, Solano County, Calif. Markley Formation. UC B 6955. Nojoqui Creek area, on west side of Nojoqui Creek, 195 m northwest from 2221, 195 m northwest from fork of old and new roads, 1,220 m southwest from M 88, 1,030 feet [315 m] northwest from 2217. Lompoc quadrangle, 30 minute series. “Coldwater-Gaviota” Formation (Undifferentiated Sacate- Gaviota). UC D 1074. Domengine Ranch quadrangle, T. 19 S., R. 15 E., sec. 20: 250 feet north, 800 m east. From moderately consolidated, light gray, coarse silty sandstone bed. Exposed outcrop is more than 3 m thick. Lateral extent of collection is about 92.5 m. This is the uppermost fossiliferous sandstone ledge 0f the Temblor For- mation in this area. It is overlain by soft greenish—gray gypsiferous, silty sandstone of the upper Temblor. This locality is about 55 m above the top of the lower “Indicator” Bed, [Fresno Co., Calif]. Temblor Formation. University of California at Riverside: UCR 6682. Large light-gray concretions of west side of Meier Canyon, 1,077 m SW 29° of hill 1314—404 m above the base of the Simi Conglomerate (Calabasas quadrangle), [Ventura Co., Calif]. Simi Conglomerate. University of Oregon: UO 139. On north bank of North Umpqua River upstream from the bend 0.4 km north of Glide, Douglas County, Oreg. [Umpqua Formation]. US. Geological Survey, Washington, D.C., register: USGS 4471. Alcatraz asphalt mine, near Sisquoc, [Lompoc quadrangle], Santa Barbara County, [Calif]. [Careaga Formation]. USGS 4765. Jasper Creek just above Jacalitos Creek, on west side of center SW1/4 sec. 6, T. 22 S., R. 15 E., [Coalinga quadrangle, Fresno County, Calif]. Etchegoin [Formation]. TERTIARY MARINE PELECYPODS: LUCINIDAE THROUGH CHAMIDAE D33 USGS 4861. Devils Den District, in “reef beds” 0.4 km south- Muir Sandstone1 ————————— Eocene. southeast of Barton’s cabin, NW1/4 sec. 23, T. 25 S., R. 18 E., Neroly Sandstone, San Pablo [Cholame quadrangle], Kerb County, [Calif.]. Vaqueros [Forma- Group ———————————— Miocene. tion]. l Niguel Formation ———————— Pliocene. Olcese Sand ——————————— Miocene. ‘i Pancho Rico Formation ————— Miocene. ‘ Phacoides Sand Memberl, mo FORWONS mgaflzzgrmmn ----- 3:535:22... OCCURRENCE‘OF PELECYPODS Pomponio Mudstone Member, . . . . Purisima Formation ————— Pliocene. Family 14mm")? through Chamdae Potato Harbor Formation1 — — — Pliocene. Name Age Puente Formation1 ——————— Miocene. California 6 Purisima Formation ——————— Miocene and Pliocene. Anchor Silt —————— l ————— Pleistocene. Ragged Valley Shale Member, Agua Sandstone Bed, Santos Arroyo Hondo Formation1 — — Eocene. Shale Member, Temblor Repetto Formation (now Formation ————— l ————— Oligocene. abandoned; strata assigned to Ardath Shale ————— l ————— Eocene. lower part of Fernando Altamira Shale Member‘i, Formation) —————————— Pliocene. Monterey Formation‘ ————— Miocene. Round Mountain Silt —————— Miocene. Avenal Sandstone — — -‘ ————— Eocene. Sacate Formation1 ——————— Eocene. Bear River Series - — —l ————— Miocene. San Diego Formation —————— Pliocene. Briones Sandstone, Sanl Pablo San Emigdio Formation ————— Eocene. Group ——————— l ————— Miocene. San Joaquin Formation ————— Pliocene. Buttonbed Sandstone lVlember, San Lorenzo Formation ————— Eocene and Oligocene. Temblor Formation ————— Miocene. San Pablo Formation or Group — Miocene. Capistrano Formation ‘ ————— Miocene and Pliocene. San Pedro Formation or Sand— — Pliocene and Pleistocene. Careaga Sandstone — ————— Pliocene. San Ramon Sandstone ————— Miocene(?). Carneros Sandstone Member, Santa Barbara Formation — — — — Pliocene and Pleistocene. Temblor Formation l ————— Miocene Santa Margarita Formation — — — Miocene. Castaic Formation— — -l ————— Miocene. Santa Susana Formation1 — — — — Paleocene. Cerros Shale Member, Fodo Santos Shale Member, Temblor Formation —————————— Paleocene. Formation —————————— Oligocene and Miocene. Cierbo Sandstone, SaniPablo Saugus Formation ———————— Pliocene and Pleistocene. Group ——————————— Miocene. Sespe Formation ———————— Eocene to Miocene. Delmar Formation, La‘Jolla Simi Conglomerate ——————— Paleocene(?). Group —————— + ————— Eocene. Sisquoc Formation ——————— Miocene and Pliocene. Domengine Formation lor Sobrante Sandstone ——————— Miocene. Sandstone - — — — l- ————— Eocene. Tahana Member, Purisima Etchegoin Formation i— ————— Miocene and Pliocene. Formation —————————— Miocene and Pliocene. Fernando Formation ————— Pliocene and Pleistocene. Tejon Formation ———————— Eocene. Foxen Mudstone— — — ————— Pliocene. Temblor Formation ——————— Oligocene and Miocene. Gaviota Formation1 — l— ————— Eocene and Oligocene. Tierra Redonda Formation — — — Miocene. Gould Shale Member, Monterey Timms Point Silt Member, San Formation - — — — l— ————— Miocene. Pedro Formation ——————— Pleistocene. Imperial Formation — l— ————— Miocene or Pliocene. Topanga Canyon Formation, Juncal Formation — — ————— Eocene. Topanga Group ———————— Miocene. La Jolla Formation or‘Group — — Eocene. Topanga Formation ——————— Miocene. Llajas Formation ———————— Eocene. Towsley Formation ——————— Miocene and Pliocene. Lodo Formation— — -‘ —————— Paleocene and Eocene. Tumey Formation1 ——————— Oligocene. Lomita Marl Member,lSan Pedro Vaqueros Formation ——————— Oligocene and Miocene. Formation — — — —l —————— Pliocene. Wildcat Group —————————— Pliocene and Pleistocene. Los Laureles Sandstonle Memberl, Wygal Sandstone Member, Monterey Formati n —————— Miocene Temblor Formation ————— Oligocene. Markley Formation —‘i —————— Eocene. Baja California peninsula: Martinez Formation —‘ —————— Paleocene. Almejas Formation ——————— Miocene and Pliocene. McLure Shale Member, Carmen Formation ——————— Pliocene. Monterey Formation ————— Miocene. Comondu Formation ——————— Miocene. Meganos Formation —l —————— Paleocene. Marquer Formation ——————— Pliocene. Merced Formation— —l —————— Pliocene and Pleistocene. San Marcos Formation ————— Pliocene. Monterey Formation l —————— Miocene. Santa Rosalia Formation — — — — Pleistocene. l Tortugas Formation ——————— Miocene. ‘ Oregon: 1Stratigraphic nomenclature used is that of the references cited in the text and does not AStoria Formation ________ Miocene- necessarily accord with that of the U.S‘. Geological Survey. Umpqua Formation ——————— Eocene. 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A Abbott, D.P., quoted, 11, 28 Abbott, R.T., cited, 5 1 quoted, 25 Abbreviations, 6 1 Abstract, 1 Acknowledgments, 6 1 mtilineata, Lucimz, 16 me (Lucirw‘rmz), 16 1 Luci'rw’ma, 5, 16; pl. 4 Phacoides, 16 (Lucimz) (Myrtea), 16 acutilineams, Phacoides, 8 1 Phacoides (Lucinoma), 16 Addicott, w.0., quoted, 17, 18, 29 1 Adegoke, 0.S., quoted, 23 Adoniorhimt, 25 1 cyclia, 7, 25; pl. 11 1 Africa, 10, 13, 15, 20, 22, 28 1 Agua Sandstone Bed, Santos Shale Member, Temblor Formation, 17, 33 1 Alaska, 5, 7, 17, 25, 26, 29 1 Alcatraz asphalt mine, Calif., 32 1 Aleutian Islands, Alaska, 25 aleuticus, Felaniella, 29 1 Almejas Formation, 19, 30, 33 Altamira Shale Member, Monterey Forma1ion, 18, 33 Alminmna, 16 America, 11, 13, 20, 25 1 Anacapa Island, unnamed Pleistocene strata, 12 Anchor Silt, 9, 17, 24, 33 1 Anderson, F.M., quoted, 22, 27, 29 1 annulata, Lucimz, 17 1 Latina (Lucimma), 17 Lucimnna, 5, 17, 24; pl. 4 1 Phacaides, 17 Anodontia, 15, 22 1 edentuloides, 21 (Anodomia), 15 1 edentuloides, 21 Anodo’ntia?, 5, 16 1 (Amdmtia7), 5, 16 inflata, 5, 16; pl. 1 1 (Anadontia), Anodontia, 15 edentuloides, Anodontia, 21 1 inflate, Anodontia, 5 (Amdontia7), Anodontia'i, 5, 16 inflata, Anodontiai, 5, 16; pl. 1 antecedens, Lucina nuttallii, 10 1 Lucim (Lucinisca) nuitallii, 4, 9; pl1. 1, 7 Lucinisca nutiallii, 9, 10 1 Phacoides nuttallii, 9 1 approximata, Lucina, 15, 28 1 Lucina (Myrtea) tenuisculpta, 15 (Pari'ilucina), 15 Pa'wilucina (Pamlucina), 5, 15; pl.14 apmoximatus, Phacoides, 15 Phacoides (Pa’r'uilucina), 15 1 arcana, Chama, 30, 31 1 Chama (Chama), 8, 30; pls. 10, 11 Arcinella, 81 1 a’rcimlla, 31 califmica, 8, 31; pl. 10 1 arcimlla, Arcinella, 31 Arctic Ocean, 25 Ardath Shale, 20, 33; pl. 6 1 Arnold, Ralph, quoted, 9, 10, 17, 18, 1'1), 24, 32 Arroyo de Arce, 31 Arroyo Hondo Formation, Ragged Valléy Shale Member, 8, 26, 27, 33 1 Asia, 10, 11, 13, 15, 16, 22 1 Astoria, Clatsop County, Oreg., 16, 291 Astoria Formation, 16, 25, 29, 33; pls.14, 7, 8 INDEX [Italic page numbers indicate major references] Atlantic coast, 24 Australia, 10—13, 15—17, 20, 22, 28 Avenal Formation, 21, 27, 33 Sandstone, 16, 20, 21, 26 Axinopsida, 25 serricata, 7, 25; pl. 8 viridis, 7, 25; plr 11 Axi’rwpsis se'ricata, 26 sericaius, 25 semicaia, 25 viridis, 25 Azinus, 24 B Bahia Banderas, Mexico; pl. 11 Bahia California Norte, 12 Bahia Concepcion, 31 Bahia Magdalena, 9, 11, 15, 28, 31 unnamed sediments, 23 Bahia Marquer, 31 unnamed strata; pl. 10 Bahia San Quintin, 9, 12, 13, 15, 31 unnamed sediments, 30 Bahia Santa Inez, 11, 12, 28, 31; pl. 11 unnamed sediments, 22 unnamed strata, 11; pls. 4, 9, 10 Bahia Santa Ynez, unnamed sediments, 23 Bahia Todo Santos, 25 Bahia Tortola, Baja California Sur, 9, 12, 13, 15, 28, 30, 32 Baja California, 9, 13, 27 geographic divisions, 1 Baja California Norte, 4—9, 10—12, 22, 23, 25, 27, 28, 31, 32 Baja California peninsula, list of formations, 33 Baja California Sur, 4—9, 10—13, 15, 17, 19,21, 23, 25, 28, 30—32; pls. 4, 5, 7, 9, 10 unnamed strata, 30 Baldwin Hills, Calif., unnamed strata, 9, 12 barbarensis, Thyasira, 25 Barker’s Ranch, Calif., 27 Bear River Series, 17, 33 bella, Lucina, 12 (Bellucina) cancellaris, Phacoias, 14 cancellaris, Lucina, 14 Bering Sea, 25 Bering Strait, Alaska, 24 Bernard, F.R., cited, 5 quoted, 30, 31 Berry, S.S., quoted, 25 bisecta, Thyasi'ra, 24, 25 (Conchocele); pl. 7 bramkampi, Lucina (Lucina7), 4 Lucina‘I, 8 (LucinaY), 8; pl. 4 Bramlette, M.N., quoted, 10 Brazil, 23 Brink Ranch House, Calif., 32 Briones Formation, 17 Briones Sandstone, San Pablo Group, 33 British Columbia, Canada, 5, 7 Broderip, W.J., quoted, 30 Bruetia, 26 traski, 26, 28 Bmetia?, 26 traski, 7, 26; pl. 8 Buttonbed Sandstone Member, Temblor Formation, 17, 18, 33 buwaldana, Diplodonta, 27 Diplodoma (Diplodonta), 7, 27; pl. 8 buwaldanus, Diplodonta, 27 Tums, 27 Cabo San Lucas, 11, 19 caffea, Turcica, 24 Calabasas quadrangle, Calif., 32 Caliente quadrangle, Calif., 32 California, 11, 17, 22, 25, 26, 31, 32 formations, 33 geographic divisions, 1 Lower, 23, 31 middle, 4—9, 11, 13, 15—21, 26—29, 31 northern, 4—8, 11 southern, 4—9, 10—13, 15—31 unnamed sediments, 27, 32 unnamed strata, 13, 28, 30 California province, 21 califmica, Arcinella, 8, 81; pl. 10 Callucina, 11 Codakia (Epilucina), 4, 11; pl. 1 Echinochama, 31 Lucina, 9—11 (Epilucina), 11 (Myrtea), 11 califormim, Phacoides (Epilucina), 11 Callucina, 4, 10, 11 califomica, 11 (Callucina), 4, 10 lampra, 4, 10; pl. 3 lingualis, 4, 10; pl. 3 (Callucina), Callucina, 4, 10 inflata, Phacoides, 16 lamp'ra, Callucina, 4, 10; p11 3 Lucina, 10 iingualis, Caliucina, 4, 10; pl, 3 Lucina, 10, 11 caloosmsis, Miltha, 19 caloosana, Phacoides, 23 Camulos quadrangle, Calif., 32 cancellaris, Linga (Pleuroiucina), 14; pl. 4 Lucina, 14 (Bellucina), 14 (Pleurolucina), 14 Phacoides (Bellucina), 14 (Pleurolucina) Lingo, 4 Canyon del Cordon, Calif., 23 Capistrano Beach, Calif., 9, 12 Capistrano Formation, 17, 25, 31, 33 (Cardiolucina) lingualis, Lucina, 10 (Cardiolucina?) lamp'ra, Lucina, 10 Cardium, 29 Careaga Formation, 17, 32 Careaga Sandstone, 9, 10, 33; pl. 7 Caribbean Sea, 11, 31 Carmen Formation, 9, 33 Carneros Sandstone Member, Temblor Formation, 18, 33 Carpenter, P.P., cited, 15 quoted, 10, 11~14, 25, 28 Carpinteria, Calif., 9 Castaic Formation, 13, 17, 19, 31, 33 Catalina Island; pl. 11 (Cavilinga) lampra, Lucina, 10 lingualis, Lucina, 10 (Cavilucina) lampms, Phacoides, 10 lingualis, Phacoides, 10 Cayucos, Calif., 12 Central America, 4—8, 14, 22, 26, 31, 32 centrifuga, Lucina nuttallii, 9 Lucinisca, 10 Cerros Island, 31 Cerros Shale Member, Lodo Formation, 8, 16, 32, 33; pl. 4 Chama, 30 drama, 30, 31 echinata, 30, 31 exogyra, 32 D41 D42 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Chama~Continued frondosa, 30 pellucida, 30, 31 spinosa, 31 squamuligem, 31 n.sp,7, 31 (Chama), 30 drama, 8, 30; pls. 10, 11 echinala, 8, 30; pls. 9, 11 frondasa, 8, 30; pls, 9, 10 pellucida; pl. 11 squamuligera, 8, 31; pl. 10 (Cham7), 31 sp., 8, 31; pl. 9 (Chama), Chama, 30, 31 arcana, Chama, 8, 30; pls. 10, 11 echinata, Chama, 8, 30; pls. 9, 11 frondosa, Chama, 8, 30; pls. 9, 10 pellucida, Chama; pl. 11 squamuligem, Chama, 8, 31; pl. 10 (Chama?), Chama, 31 Chum, sp., 8, 31; pl. 9 Chamidae, 1, 30 childreni, Phtwoides, 18, 24 Chiquita, Cndakia, 12 Cte'na (Ctemz), 12; pl. 2 Cholame quadrangle, Calif., 33 Cierbo Sandstone, 9, 17 San Pablo Group, 13, 27, 29, 31, 33 Claibomites, 19 diegoensis, 20 (Claibmites), 19 diegoerisis, 5, 20; pl. 6 (Codalucinu), 20 muirensis, 5. 20; pl. 6 tuWi, 5, 20; pl. 7 (Claibomites), Claibornites, 19 diegoensis, Claibomites, 5, 20; pl. 6 Clark, B,L., quoted, 12, 13, 16, 19, 21, 26, 27 Clatsop County, Oreg., 29 Clayton, Calif., 26 Coalinga, Calif., 29 Coalinga quadrangle, Calif., 32 Codakia, 4, 11 Chiquita, 12 distinguenda, 11, 12 mxicana, 12 orbicularis, 11 orbiculata, 12 tig'rina, 11 (Codakia), 4, 11 distinguenda, 4, 11; pls. 1, 2 (Epilucinu), 4, 11 califomica, 4, 11 ; pl. 1 (Jagmiia) mexicana, 12 (Codakia), Codakia, 4, 11 distinguenda, Codakia, 4, 11; pls. 1, 2 Lucinu, 11 Codulucina, 20 (Codalucina), Claibomites, 20 muirensis, Claibo’mites, 5, 20; pl. 6 tumeri, Claibornites, 5, 20; pl. 7 “Coldwater-Gaviota” Formation, 32 Colombia, 22 columbiensis, Diva'ricella, 22 Comondu Formation, 12, 15, 23, 28, 30, 31, 33; pl, 4 Concepcion, Baja California Sur, 12 Conchocele disjuncta, 24 (Conchocele), Thyasira, 24 bisecta, Thyasira; pl. 7 disjuncta, Thyasim, 7, 24; pl, 7 folgeri, Thyasim, 7, 24; pl. 7 Concord quadrangle, Calif., 32 Conrad, T.A., quoted, 9, 11, 16, 24, 29, 32 Contra Costa County, Calif., 8, 19, 20, 23, 26, 27, 32 contracta, Lucina, 16 Corey, W.H,, quoted, 23, 29 cited, 31 cornea, Diplodonta, 29, 3O Diplodonta (F ellmiella), 29 Felaniella (Feloniella), 7, 29; pls. 9, 10 Lucina, 29 Coronados Island, unnamed strata, 11 Costa Rica, 29 crmlla, Phacoides, 15 creamed, Diplodonta, 26 Diplodonta (Diplodonta), 7, 26; pl. 8 7Lucina, 26 Phacoides, 26 Cryptodon, 24, 25 flexuosus, 24 ser'ricatus, 25 Ctm, 4, 12 mxicana, 12 (Ctena), 4, 12 Chiquita, 12; pl. 2 mexicana, 4, 12; pl. 2 Cterw. species, eastern Pacific, 12 West Indian, 12 (Ctena), Ctena, 4, 12 Chiquita, Ctena, 12 mxicana, Ctena, 4, 12; pl. 2 cummulata, “Lucina”, 22 cumulata, Diva'ricella, 22 Divaricella? (Egracina'l), 6, 22; pl. 7 Lucina, 22 cycliu, Adontm‘hina, 7, 25; pl. 11 D Dall, W.H,, quoted, 10, 15, 18, 26, 31 dalli, Lucina, 13 Deadmans Island, 12, 25 unnamed sediments, 24 Delmar Formation, La Jolla Group, 33 Delmar Sand, 20 Devils Den District, Calif, 33 Devil's Kitchen, Calif, 23, 32 diabloi (diaboli), Lucim, 21 (diaboli), Lucina diabloi, 21 diaboli, Lucina. (Lucim?) 4 Lamina? (Lucina?), 8; pl. 4 Phacoides, 8 Dickerson, R.E., quoted, 8, 16, 20, 21 diegoemis, Claibomites, 20 Claibomites (Claibomites), 5, 20; pl. 6 Lucinu, 20 Diplodonta, 26, 29 buwaldana, 27 buwaldanus, 27 cornea, 29, 30 cretacea, 26 harfordi, 27, 29, 30 impolita, 28 orbella, 27, 28 orbellus, 27, 28 parilis, 27, 29 polita, 26 sericata, 29 sewicata, 27 stephensmi, 27 subquadmta, 28 traski, 26 unisulcatus, 26 3,3,, 28 (Diplodtmta), 26 buwaLdzma, 7, 27; pl, 8 cretacea, 7, 26; pl. 8 orbella, 7, 27; pl. 8 polita, 7, 26; pl. 8 slephmsoni, 7, 27; pl, 8 subquadratu, 7, 28; pl. 8 unisulcatus, 7, 26; pl. 7 (Felaniella) coma, 29 parilis, 29 (Zmysina), 28 paCifica, 7, 28; pl. 8 (Diplodoma), Diplodonta, 26 buwaldana, Diplodonta, 7, 27; pl. 8 cretacea, Diplodonta, 7, 26; pl. 8 orbella, Diplodonta, 7, 27; pl. 8 polita, Diplodonta, 7, 26; pl. 8 stephensoni, Diplodontu, 7, 27; pl. 8 subquadmta, Dipladonta, 7, 28; pl. 8 unisulcatus, Diplodonta, 7, 26; pl. 7 disjuncta, Conchocele, 24 Thyasim, 24, 25 (Comhocele), 7, 21,; pl. 7 distingiwnda, Codakia, 11, 12 Codakia. (Codakia), 4, 11; pls. 1, 2 Lucina (Codakia), 11 Divalinga, 22 (Divalinga), 22 ebu’mea, 6, 22; pl. 7 (Divalinga), Divalinga, 22 eburrwa, Divalinga, 6, 22; pl. 7 divaricata, Divaricella, 22 Divaricella, 22 columbiensis, 22 cumulata, 22 divaricata, 22 elmrrwa, 22 lucasana, 22; pl. 7 omata, 22 perpamla, 22 DivaricelLaY, 22 (Egrum'na), 22 (Emacina?) 22 cumulata, 6, 22; pl. 7 Diva‘ricellime, 22 Domengine Formation, 20, 21, 23, 26, 27, 32, 33; pl. 7 Domengine Ranch quadrangle, Calif., 32 Domeng'lne Sandstone, 21, 33 Dasinia. gyrata, 20 Douglas County, Oreg., 21, 32 Dune Terrace, Califi, 9 Durham, J.W., quoted, 10, 14, 30 E East Africa, 20 ebumea, Divali'nga (Divalinga), 6, 22; pl. 7 Divaricella, 22 Lucina, 22 echinata, Chum, 30, 31 Chama. (Chama), 8, 80; pls. 9, 11 Echimchama arcinellu, 31 californica, 31 Ecuador, 12, 22, 30 edentula, Loripes, 21 Pegophyse'ma, 22 edentuloides, Anodontia, 21 Anodontia (Anodontia), 21 Lo'ripes, 21 Luciml, 21 Pegophysema, 21, 22 (Pegophyse‘ma), 6, 21; pl. 11 effingeri, Here (Here), 4, 13; pls. 2, 3 Lucinu (Here), 13 Eg’raci'na, 22 (Egmcina), Divaricella'I, 22 (EgraciMY), Divaricella'I, 22 cumulata, Diva'ricellal 6, 22, pl. 7 Elk River Formation, 17 Eomiltha, 21 (Eomilthu), Gibbolucina, 20 gyrata, Gibbolucina, 6, 20; pl. 7 Miltha, 20 pandata, Miltha, 21 (Eomiltha7), Gibbolucina, 21 packi, Gibbolucina, 6, 21; pl. 6 Miltha, 21 Epilucina, 11 (Epilucina), Codakia, 4, 11 califomica, Codakia, 4, 11 ; pl. 1 Lucina, 11 califomicus, Phacoides, 11 Etchegoin Formation, 9, 13, 17~19, 27—29, 31—33; pl. 9 Europe, 10, 11—13, 15—17, 19—22, 26, 28, 30 western, 12 excavuta, Here, 12, 13 Here (Here), 4, 13; pl. 3 Lucina, 13, 17, 23 (Here), 13, 23 5.8., 23 temblo’rmis, Here, 23 Lucina (Here), 23 “excavata temblo‘rensis, Lucina (Here),” 23; pl. 3 exogyra, Chama, 32 Pseudochama, 32 (Pseudochama), 8, 32; pls. 9—11 Felam'ella, 28 aleuticus, 29 harfo’rdi, 29 orbellus, 29 (Felaniella), 28 cornea, 7, 29; pls. 9, 10 harfordi, 7, 29; pl. 8 parilis, 7, 29; pl. 8 (Zemysia) sem'cata, 29 (Felamlella), Felaniella, 28 cornea, Diplodonta, 29 Felam'ella, 7, 29; pls. 9, 10 harfordi, Felaniella, 7, 29; pl. 8 parilis, Diplodonta, 29 Felaniella, 7, 29; pl. 8 sericatus, Taras, 29 Fernando Formation, 9, 10, 12, 13, 15, 17, 18, 24, 25, 28, 30—33; pl. 3 flewosa, Lucina, 24 Tellina, 24 Thyasira, 24 flexuosus, Cryptodon, 24 Florida, 19, 23 folgem', Thyasi’ra, 24 Thyasira (Conchocele), 7, 24; pl. 7 formation, 4 geologic, 1 Fort Tejon, Calif., 22 Fossil localities, 92 Foxen Mudstone, 10, 26, 33 Fresno County, Calif., 8, 16, 19, 21, 27, 29, 32 frondosa, Chama, 3O Chama (Chama), 8, 30; pls. 9, 10 G Gabb, W.M., quoted, 13, 20, 22, 23, 26 Galapagos Islands, 28, 30, 31 Gale, H.R., quoted, 11, 13, 15, 28, 29 Gaviota Formation, 13, 32, 33 undifferentiated, 13; pls. 2, 3 gaylordi, Phacoides, 23 ”Lum'na,” 6, 23; pl. 7 Gemmell, Joyce, quoted, 28 Geologic formations, cited, 33 cited for occurrence of Pelecypods, 33 Geologic time, classification, 4 Gibbolucina, 20 (Eomiltha), 20 gyrata, 6, 20; pl. 7 (Eomiltha?), 21 packi, 6, 21; pl. 6 Givens, C.R., quoted, 20 Glide, 0reg., 21, 32 Goleta, Calif., 9 Golfo de California, 11, 12, 15, 19, 30 Gordon, Mackenzie, Jr., cited, 5 Gould Shale Member, Monterey Formation, 7, 33 Gould, A.A., quoted, 27 gouldi, Thyasira, 24 Gouldii, Lucina, 24 gould'ii, Thyasira, 24 (Thyas’i’ra), 7, 24; Pl. 7 Grant, U.S., IV, cited, 5, 15 quoted, 9—11, 13, 15, 17, 19, 24, 28, 29, 0 Guaymas, 23 Gulf of California, 9 Gulf of Darien, Colombia, 25 Gulf of Mexico, 21 Gulf of Nicoiya, 29 gyrata, Dosim, 20 Gibbolum'na (Emiltha), 6, 20; pl. 7 Luc'im, 20 Miltha (Emiltha), 20 Phacoides, 19, 20, 21 INDEX H Haderlie, E.C., quoted, 11, 28 Hanna, GD., quoted, 22 hannai, Here, 12 Here (Here), 4, 12; pl. 2 Lucina (Here), 12 hannibali, Lucinoma, 17 harfordi, Diplodonta, 27, 29, 30 Felaniella, 29 (Felanietla), 7, 29; pl, 8 Taras, 29 Here, 4, 12 excavata, 12, 13 temblorensis, 23 hannai, 12 (Here), 4, 12 ejffingeri, 4, l3; pls. 2, 3 excavata, 4, 13; pl. 3 hannai, 4, 12; pl. 2 (Illesca), 12 (Here), Here, 4, 12 ejfingeri, Here, 4, 13; pls. 2, 3 Luctna, 13, 23 excavata, Here, 4, 13; pl. 3 Lucina, 13 Lucina, 5.5., 23 temblwensis, Lucina, 23 hannai, Here, 4, 12; pl. 2 Lucina, 12 richthafeni, Lucina, 13, 23 Phacoides, 1.9 “(Here) excavata temblorensis, Lucina,” 28; pl. 3 Hertlein, L.G., cited, 5, 15 quoted, 9—11, 13, 15, 17, 19, 24, 28, 29, 30 Hertz, C.Ml, quoted, 28 Hilltop Quarry, San Pedro, Calif., 25 Huntington Beach, Calif., 9 Iliuliuk, Alaska, 26 (Iltesca), Here, 12 Imperial Formation, 11, 19, 22, 23, 30, 31, 33; pls. 5—7 impolita, Diplodonta, 28 Indian Ocean, 12, 22 inflata, Anodontia (Anodontia), 5 Anodontia? (Anode/Mia?) 16; pl. 1 Phacoides (Callucma), 16 intma, Lucina tenuisculpta, l5 Parm'lucina tmuisculpta, 15 (Pamlucina), 5 tenuisculpta, 15; pl. 4 intensus, Lucina (Pamlucina), 15 Phacoides (Pamilucina), 15 Introduction, 1 Iquique, Chile; pl. 11 Isla Carmen, 11, 28, 31 Isla Cedros, 31; pl. 10 unnamed strata, 12 Isla Guadalupe, 25 Isla Margarita, 15 Isla Monserrate, 10 unnamed sediments, 23 Isla Tiburon, unnamed sediments, 30 Islas Coronados, 9, 32; pls. 1—3 unnamed sediments, 12, 23, 28, 31 unnamed strata, 10, 19; pls. 5, 7, 9 J,K jacalitosana, Lucina (Mikhail), 19 Miltha, 19 (Miltha7), 5, 19; pl. 9 Paphia, 19 (Jago’aia) micana, Codakia, 12 Japan, 9, 16, 25, 26 Jasper Creek, Calif., 32 joamu's, Miltha, 23 Miltha‘1, 24 Phacoides, 18, 23 nomen nudum, 28 Joaquin Rocks quadrangle, Calif., 32 D43 Jordan, E.K., quoted, 9, 10, 12, 14, 15, 28, 30 Juncal Formation, 20, 27, 33; pl. 6 Keen, A.M., cited, 1, 5 quoted, 9, 11—13, 17, 22, 30, 31 Kern County, Calif., 9, 16, 18, 22724, 27, 32, 33 Kleinpell, R.M., 13 L La Jolla Formation, 16, 20, 21, 26, 33 La Jolla Group, 33 Delmar Formation, 33 La Jolla quadrangle, Calif., 32 La Paz, Baja California Sur, 10, 21 Laguna Scammon, 9 Lake County, Calif., 8, 20, 32 lamp’ra, Calluci'na (Callucina), 4, 10; pl. 3 Lucina, 10 Lucina (Callucina), 10 (Cardiolucina7), 10 (Cam'linga), 10 lamms, Phacoides (Cavilucina), 10 Lincoln Creek Formation, 17 Lingo, 4, 13 8.5., 13 (Pleurolucma), 4, 13 cancellaris, 4, 11,; pl. 4 lingualis, Calluc’ina (Callucina), 4, 10; pl. 3 Lucim, 10 (Calluc’ina), 10, 11 (Cardiolucina), 10 (Cam'linga), 10 (Myrtea), 10 Phacoides, (Cavilucma), 10 Llajas Formation, 20, 21, 33 Lodo Formation, 20, 33 Cerros Shale Member, 8, 16, 32, 33 Loel, Wayne, cited, 31 quoted, 23, 29 Lomita Marl Member, San Pedro Formation, 24, 25, 33; pl. 11 Lompoc quadrangle, Calif., 32 Lord Hood Island, 31 Loripes edentula, 21 edentuloides, 21 parilis, 29 Los Angeles County, Calif., 25 Los Laureles Sandstone Member, Monterey Formation, 17, 33 Lowe, H.N., quoted, 31 Lower California, 23 Lower Lake, Lake County, Calif., 20, 32 lucasana, Divaricella, 22; pl. 7 Lucina, 4, 7, 11, 29 mtilineata, 16 annulata, 17 apprarimata, 15, 28 bella, 12 caltfomica, 9—11 cancella‘m's, 14 contrwta, 16 coma, 29 cumulata, 22 dalli, 13 diabloi (diaboli), 21 diegomsis, 20 churned, 22 edentuloides, 21 excavata, 13, 17, 23 flexuosa, 24 Gouldii, 24 gy'rata, 20 lamp/m, 10, 11 lingualis, 10 mm, 23 m'tens, 29 nuttallii, 9 antecedens, 10 centnfuga, 9 nuttallii, 9 orbella, 27 packi, 21 pectimta, 12 D44 Lwim—Continued prolongatu, 10 richthofem, 13; pl. 3 roselmrgensis, 21 serioam, 29 tenuisculpta, 15, 28 intensa, 15 tenuisculptus, 15 mm, 20 wattsi, 23 (Bellwim) cancellan's, 14 (Callucina) lampra, 10 lingualis, 10, 11 (Cardioluct'm) lingualis, 10 (Cardiolucma?) lampra, 10 (Cam'linga) lamp'ra, 10 linmlis, 10 (Codakia) distingwmda, 11 (Epiluc’inu) californica, 11 (Here) eflinge'ri, 13 excavate, 13, 23 3.5., 23 temblo’rensis, 23 hunmn‘, 12 richthofeni, 13, 23 (Lucina), 7 (Luciml?) bramkampi, 4 diaboli, 4 quadruta, 4 (Lucinisca), 4, 9 muda, 4, 9; pl. 1 nuttallii, 9 untecedens, 4, 9; pls. 1, 7 nuttallii, 4, 9; pl. 1 (Lucino'mu) ucutilineata, 16 annulata, 17 (Miltha) xantusi, 18 (Miltha?) jacalitosana, 19 (Myrtea) califomia, 11 lingualis, 10 nipponica, 11 nuttallii, 9 tenuisculpta, 14 tenuisculpta approximata, 15 (Puwilucina) approximate, 15 i’ntensus, 15 (Pleurolucina) cancellaris, 14 “Lucina.” cummulata, 22 gaylordi, 6, 23; pl. 7 nasuta, 6, 23; pl. 5 wattsi, 6, 29; pl. 11 “Lucina. (Here) excavata temblo’rensis,” 23; pl. 3 Lucina7, 4 bm’rnkumpi, 8 sp., 8 (Lucina?), 4, 10 Mamkampi, 8; pl. 4 diaboli, 8; pl. 4 quadrata, 8; pl. 4 7Lucina Lvretucea, 26 (Lucina), Lucina, 7 (Myrtea) acutilineato, 16 (Lucina?), Lucina'Z, 4, 10 bramkampi, Lucina, 4 Lucina?, 8; pl. 4 diubolt', Lucina, 4 Lucina'I, 8; pl. 4 quadrata, Lucinu, 4 Lucino?, 8; pl. 4 Lucimzcea, 18 Lucim'dae, 1, 7 LucinidueY, 23 genus uncertain, 23 Lucinimw, 7 Lucim'scu aff. L. nuttalli, 9 Lucimsca centrifuge, 10 muda, 9 nuttalli, 9, 10 nuttallii, 9, 10 antecedens, 9, 10 (Lucinisca), Lucina, 4, 9 menuda, Lucim, 4, 9; pl. 1 (Lmnisca), Lucina—Continued nuttalli'i, Lucina, 9 antecedens, Lucim, 4, 9; pls. 1, 7 nuttallii, Lucimz, 4, 9; pl. 1 Lucino’ma, 16, 23 Mutilineata, 5, 16; pl. 4 annuLata, 5, 17, 24; pl. 4 annulatu—Turc’ica. caffea community, 21. hann'ibali, 17 (Lucimma) amtilineata, Lucina, 16 mtil’ineatus, Phacoides, 16 annulata, Lumina, 17 Luc'mopsis undulatu, 28 M Markley Formation, 12, 13, 32, 33; pl. 2 Marquer Formation, 9, 10-12, 23, 25, 30—33; pls. 3, 9, 10 Marsh Ranch, Calif., 20, 26 Martin, Bruce, quoted, 27 Martinez, Calif., 23, 26 Martinez Formation, 8, 18, 20, 26, 32, 33; pls. 4, 6—8 Martinez Group, 32 “Martinez" Formation, 32 Massachusetts Bay, 24 Mazatlan, Mexico, 12—14, 28 McLure Shale Member, Monterey Formation, 13, 17, 18, 29, 33 Mediterranean Sea, 25, 32 Meganos Formation, 19, 21, 26, 32, 33; pls. 5, 8 mgunosensis, Miltha (Miltha'l), 5, 19; pl. 5 Phacoides, 19 Meier Canyon, Calif., 32 made, Lucina (Lucim'sca), 4, 9; pl. 1 Lucim'sca, 9 Merced Formation, 17, 28, 33 micam, Codakia, 12 Codakia (Jagonia), 12 Ctena, 12 (Cte'rba), 4, 12; pl. 2 Mexico, 9—11, 13, 19, 22, 28 Meyers, B.W., quoted, 28 Miltha, 17 culoosaensis, 19 jacalitosam, 19 jommis, 23 packi, 21 parsom', 18 sanctzwcmcis, 18, 19 xantusi, 18, 19 (Eomiltha) gymta, 20 pandata, 21 (Eomiltha’!) packi, 21 (Milthu), 18 parsom', 5, 18; pl. 6 sanctwc’mcis, 5, 18, 21; pls. 5, 6 wantusi, 5, 18; pls. 5, 6 (MilthuY), 19 jacalitosaml, 5, 19; pl. 9 mgmwsensis, 5, 19; pl. 5 (sensu stricto), 21 Miltha? joannis, 24 (Miltha), Miltha, 18 parsoni, Miltha, 5, 18; pl. 6 sanctaecrucis, Miltha, 5, 18, 21; pls. 5, 6 Phacoides, 18 xantusi, Lucim, 18 Miltha, 5, 18; pls. 5, 6 Phacoides, 18 (MilthaY), Miltha, 19 jacalitosana, Lucina, 19 Miltha, 5, 19; pl. 9 meganosensis, Miltha, 5, 19; pl. 5 Milthimw, 17 Mission Bay, Califi, 9 Mollusks, marine, Baja California, 1 marine, California, 1 classification, 1 Tertiary, 1 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Mollusks, marine, Baja California—Continued species, geographic distribution, 1 geologic age range, 1 geologic distribution, 1 supplementary descriptions, 1 synonymy, 1 type, 1 Monterey, Ca1if.; pl. 11 Monterey Formation, 13, 17, 18, 33 Altamira Shale Member, 18, 33 Gould Shale Member, 17, 33 Los Laureles Sandstone Member, 17 McLure Shale Member, 13, 17, 18, 29, 33 Moonstone Beach, Calif., unnamed strata, 25 Moore, E.Ji, quoted, 16, 17, 25, 29 Moore, R.C., cited, 1 Mount Diablo, Calif., 20, 26 Mount Diablo quadrangle, Calif., 8, 32 Muir Sandstone, 16, 21, 33 muirmsis, Claibmites (Codaluc'im), 5, 20; pl. 6 Pluwoides, 20 Myrtea, 16 (Myrtea), 16 inflow, 5, 16; pl. 4 (Myrth) rosebwrgensis, 21 (sensu sm‘cto), 21 (Myrtea), Myrtea, 16 taflam, Myrtea, 5, 16‘; pl. 4 Phacoides, 16 tenuisculpta approximata, Lucina, 15 Lucina, 14 Myrteniae, 16 Myrtuc’im, 21 roseburgensis, 6, 21; pl. 7 (Myrtuc’imz) Toseburgensis, Myrtea, 21 “Mysia.” polita, 27 ”Mysia?” polita, 26 7Mysia politu, 26 N Napa quadrangle, Calif., 32 nasuta, Lucimz, 23 “Luc'im,” 6, 28; pl. 5 Nelson, R.N., quoted, 26 Neptunea tabulata—Thyasira gouldii community, 24 Neroly Sandstone, 9, 17 San Pablo Group, 13, 27—29, 31, 33 New Zealand, 16, 17, 18 Newport, Calif., 31 Newport Bay, Calif., 9, 30; pl. 11 unnamed sediments, 15 Niguel Formation, 9, 13, 17, 29, 31, 33 nippo’nica, Lucim (Myrtea), 11 m'tens, Lucina, 29 Nojoqui Creek, Calif., 32 North Africa, 12, 21 North America, 10—12, 14—17, 19—22, 24, 26, 28, 30 western, 12, 25 North Umpqua River, Oreg., 21, 32 nuttalli, Lucim'sca, 9, 10 nuttallii, Lucina, 9 Luct'mz nuttallii, 9 (Lminisca), 9 nuttallii, 4, 9; pl. 1 (Myrtea), 9 Luciniscu, 9, 10 Phtwoides, 9, 10 antecedem, Lucimz, 10 Lucim (Lucimsca), 4, 9; pls. 1, 7 Lucimlscu, 9, 10 Phacoides, 9 centrzfltga, Lucimz, 9 nuttallii, Lucina, 9 Lucina. (Luciniscu), 4, 9; pl. 1 0 Olcese Sand, 17, 18, 33 Olsson, A.A., cited, 1, 22 quoted, 11, 13, 15, 19, 22, 30 Orange County, Calif., 30 o’rbella, Diplodo’nta, 27, 28 l Diplodonta (Diplodonta), 7, 27; pl. 8 Lucimz, 27 orbellus, Diplodonta, 27, 28 ‘ Falaniella, 29 Tums, 27 o’rbicutaris, Codakia, 11 o’rbiculata, Codakia, 12 l Oregon, 5—8, 17, 21, 25, 31, 32 formations, 33 southern, 21 mm, Divaflcella, 22 l P Pacific Ocean, 11, 12, 15, 16, 26, 28 eastern, 6—8, 14, 24, 25, 28 l north, 24 southwestern, 30, 32 l western, 22, 28 ‘ Pacific Beach, Calif., 9 Pacific Palisades, Calif., 9 pamfwa, Diplodonta (Zemysim), 7, 28; pl. l8 packi, Gibbolucimz (Eomiltha7), 6,21; pl. (1 Lucina, 21 Miltha, 21 ‘ (Eomt'ltlw'l), 21 Palos Verdes Hills, Calif., 12 l Panama, 11, 15, 22, 30, 31 Panamic molluscan province, 18 Pancho Rico Formation, 9, 13, 33 ‘ pandata, Miltha (Emiltha), 21 Paphia jacalilosamz, 19 l parilis, Diplodonta, 27, 29 Diplodtmta. (Feloniella), 29 Felamlella (Feloniella), 7, 29; pl. 8 ‘ Loripes, 29 Tums, 29 sen'catus, Tums, 29 Parson‘s Peak, Calif., 32 l parsoni, Miltha, 18 Miltha. (Miltha), 5, 18; pl. 6 Pa’rvilucim, 14 Pamlucma tenuisculpta intense, 15 l tenuisculpta tenuisculpta, 15 (Parm'lucina), 14 approximata, 5, 15; pl. 4 ‘ intense, 5 tenuisculpta, 5 intensa, 15; pl. 4 tenuisculpta, 14; pl. 4 (Pamilucimz) approximate, Lucina, 15 ‘ approximata, Parm'luc‘imz, 5, 15; pl. 11 l approximtus, Phacoides, 15 intensa, Paruilucina, 5 intensus, Lucim, 15 l Phacoides, 15 tenuisculpta, Pamn'lucina, 15 ‘ intense, Parm'lucina, 15; pl. 4 + l. 4 tenm'sculpta, Pamlucina, 5, 14; tenuisculptus, Phacoias, 14 pectinata, Lucina, 12 l Pegophyse’ma, 21 ‘ edentuba, 22 edentuloides, 21, 22 (Pegophysema), 21 edentulaides, 6, 21; pl. 11 l (Pegophysema), Pegophysema, 21 ‘ edentuloides, Pegophysema, 6, 21; pl.‘ 11 Pelecypods, species, 1 systematics, 7 pellmda, Chama, 30, 31 l Chama (Chama); pl. 11 Pennsylvania asphalt mine, 10 perpamla, Divan‘cella, 22 Peru, 23, 30 l Phacoides, 21 acutilmeata, 16 acutilimatus, 8 ‘ annulata, 17 approximatus, 15 INDEX Phacoides—Continued caloasana, 23 childrem', 18, 24 c’rmlla, 15 cretacea, 26 diaboli, 8 gaylordt', 23 gymta, 19, 20, 21 joannis, 18, 23 women nudum, 23 meganosensis, 19 muiremis, 20 nuttallt'i, 9, 10 antecedens, 9 quadrata, 8 richthofeni, 13 tenuisculptus, 15 tumm‘, 20 zantusi, 18, 23, 24 (Bellucim) cancella'ris, 14 (Calluc'im) inflate, 16 (Cam'lucina) Lemmas, 10 lingualis, 10 (Epiluc’im) califomicus, 11 (Here) Tichthofem', 13 (Lucinoma) acutilineatus, 16 (Miltha) samttwcmcis, 18 xantusi, 18 (Myrtea) tuflana, 16 (Pamlucinu) approximatus, 15 intensus, 15 tenmlsmlptus, 14 Phacoides Sand Member, Temblor Formation, 13, 17, 33 so-called, Temblor Formation, 29 Phacoides Sand, Temblor Formation, 18 Phi]ippi, R.A., quoted, 14 Philippine Islands, 29 Pico Formation, 9, 13, 15, 19, 25, 28, 31—33; pls. 3, 5, 6 Pilsbry, H.A., quoted, 31 Pleasants Creek, Calif., 32 (Pleurolucina), Lingo, 4, 13 cancellaris, Linga, 4, 14; pl. 4 Lavina, 14 polita, Diplodonta, 26 Diplodonta (Diplodonta), 7, 26; pl. 8 “Mysia?”, 26 YMysia, 26 politus, Tams(7), 26 Pomponio Mudstone Member, Purisima Formation, 17, 33 Potato Harbor Formation, 12, 33 Potrero Canyon, Santa Monica Mountains, Calif., 9, 24 unnamed sediments, 17 Procedure, 1 prolongata, Lucimz, 10 Pseudochama, 81 exogyra, 32 (Pseudocha'ma), 32 exogyra, 8, 32; pls. 9—11 (Pseudochama), Pseudocham, 32 exogym, Pseudochama, 8, 32; pls. 9—11 Ptychma, 24 Puente Coyote, unnamed sediments, 23 Puente El Pulpito, Baja California Sur, 10, 19 unnamed sediments, 23 Puente Formation, 13, 33 Puerto Potrero, 30 Puget Sound, Wash, 25; pl. 8 Punta San Telmo, unnamed sediments, 3O Purisima Formation, 9, 10, 17, 33 Pomponio Mudstone Member, 17, 33 Tahana Member, 33 Purpose and scope, 1 quadrata, Phtwoides, 8 Lavina (Lucina7), 4 Lucina'! (LwinaY), 8; pl. 4 Ragged Valley Shale Member, Arroyo Hondo Formation, 8, 26, 27, 33 Reeve, Lovell, quoted, 17, 22, 29 References, 34 D45 Repetto Formation, 33 richthofeni, Lucim, 13 Lucina (Here), 13, 23 Phucoides, 13 (Here), 13 Rio Dell Formation, 17 Rose Canyon, Calif., 32 roseburgensis, Lamina, 21 Myrtea (Myrtea), 21 Myrtucma, 6, 21; pl. 7 Round Mountain Silt, 9, 18, 27, 32, 33; pls. 1, 8 S Sacate Formation, 13, 32, 33; pls. 2, 3 undifferentiated, 13 Sacate-Gaviota Formations, undifferentiated, 32; pls. 2, 3 Sakamoto, Kenji, 4 Salt Creek, Calif., 32 San Clemente Island, 12 San Diego, Calif., 15, 24, 27 San Diego County, Calif., 15, 20, 27, 32 San Diego Formation, 9, 10, 12, 13, 15, 17, 19, 24, 28, 30, 31, 33; pls. 1, 3, 4, 7—10 San Emigdio Creek, Calif., 23, 32 San Emigdio Formation, 13, 16, 23, 24, 32, 33; pls. 1, 7 San Fernando Valley, Los Angeles County, Calif., 13 San Francisco Bay, Calif; pl. 4 San Ignacio, 9 San Joaquin Formation, 31, 33 San Juan, Lower California, 23 San Juan del Sur, Nicaragua, 31 San Lorenzo Formation, 17, 24, 32, 33 San Marcos Formation, 30, 33 San Nicolas Island, 12 unnamed sediments, 31 San Pablo Formation, 17, 28, 31, 33; pls. 4, 8 San Pablo Group, 33 San Pablo Group, Briones Sandstone, 33 Cierbo Sandstone, 27, 29, 31, 33 Neroly Sandstone, 13, 27—29, 31, 33 San Pedro, Calif., 24 San Pedro Formation, 9, 12, 17, 25, 27, 28, 31—33 Lomita Marl Member, 24, 25 Timms Point Silt Member, 9, 12, 17, 24, 25, 28, 32, 33 San Pedro Harbor, Calif., 12 San Pedro Sand, 33; pl. 7 San Quintin Bay, 15 San Ramon Sandstone, 27, 33; pl. 8 sanctwmcis, Miltha, 18, 19 Miltha (Miltha), 5, 18, 21; pls. 5, 6 Phacoides (Miltlm), 18 Santa Barbara, Calif., 32 Santa Barbara County, Calif., 9, 13, 32 Santa Barbara Formation, 9, 12, 17, 32, 33 Santa Barbara Island, 12 Santa Cruz Island, 12 unnamed strata, 12 Santa Margarita Formation, 9, 11, 13, 17—19, 29, 33 Santa Monica Mountains, 17, 24 Potrero Canyon, 24 Santa Rosalia, 23 Santa Rosalia Formation, 33 Santa Susana Formation, 26, 33 Santos Shale Member, Temblor Formation, 17, 33 Saugus Formation, 17, 30, 33 Saxolucina, 20 Schilling, K.H., quoted, 16, 23, 24 Scott, P.H., quoted, 25 sericata, Axinopsis, 26 Diplodonta, 29 Feltmiella (Zemysia), 29 Lucina, 29 se'ricatus, Am'nopsis, 25 Tums, 29 (Feloniella), 29 parilis, 29 serm‘cata, Axinopsida, 7, 25; pl. 8 Am'nopsis, 25 Diplodonta, 27 serm'catus, Cryptodon, 25 Sespe Formation, 18, 33 D46 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Signal Hill, Calif., 9 Simi Conglomerate, 28, 32, 33; pl. 8 Simi Hills, Calif., 28, 32 Sisquoc Formation, 10, 33 Smith, A.G., cited, 5 Sobrante Sandstone, 17, 33 Solano County, Calif., 12, 32 South America, 4‘8, 31 species, habitat, 5 holotype, 4 spinosa, Chama, 31 Spitzbergen, 25 squamuligem, Chama, 31 Chama (Chemo), 8, 31; pl. 10 St. Elena, Columbia, 22 Stanley, S.M,, cited, 5 Stanton, T,W., quoted, 20 Station Diego, San Diego County, Calif., 9, 11 stephensoni, Diplodonta, 27 Dipladonta (Diplodoma), 7, 27; pl. 8 Stewart, R.B., cited, 13, 23 Stratigraphic nomenclature, 1 stratigraphic, units, age, 1, 4 units, habitat, 5 mollusks, species, holotype, 4, 5 subquudmta, Diplodonta, 28 Diplodonta (Diplodonta), 7, 28; pl. 8 subquadratus, Ta/rus, 28 Susuki, Takeo, quoted, 27, 29 Systematics, Pelecypods, 7 T tabulata, Neptunea, 24 taffana, Myrtea (Myrtea), 16; pl. 4 Phacoides (Myrtea), 16 (Myrtea) Myrtea, 5 Tahana Member, Purisima Formation, 9, 33 Tums buwaldanus, 27 cretaceus, 27 harfo’rdi, 29 orbellus, 27 parilis, 29 sericatus, 29 sericatus, 29 subquadmtus, 28 unisulcatus, 26, 27 (Felam'ella) sericalus, 29 TamsU) politus, 26 Tejon Formation, 20—23, 26, 33; pls. 5, 6 Tejon Group, 32 Telling. fleamosa, 24 Tellinid, 23 Temblor Formation, 13, ‘17, 23, 27729, 32, 33; pls. 3, s Buttonbed Sandstone Member, 17, 18, 33 Carneros Sandstone Member, 18, 33 Phacoides Sand, 18 so-called, 29 Phacoides Sand Member, 13, 17, 33 Phacoides Sand, so-called, 29 Santos Shale Member, 33 Agua Sandstone Bed, 17, 33 Wygal Sandstone Member, 13, 17, 18, 29, 33 temblorensis, Here excavata, 23 Lucina (Here) excavate, 23 "temblnrensis, Lucina (Here) excavatu,” 23; pl. 3 tenuisculpta, Lucina, 14, 15, 28 Lucina, n.s., 14 (Myrtea), 14 (Pamilucina), 14 Phacoides, 14 approximate, Lucina (Myrtea), 15 intense, Lucina, 15 Pamilucimt, 15 (Pamilucim), 15; pl, 4 tenuiswlpta, Pamilucinu, 15 Pamilucina (Pawilucina), 14; pls. 4, 15 tenuisculptus, Lucina, 15 Phacoides, 15 (Pawilucina), 14 Thompson, I.E., cited, 5 Thyasim, 24 barbarensis, 25 bisectq, 24, 25 disjuncta, 24, 25 flexuosa, 24 folge’rt, 24 gouldi, 24 gouldii, 24 gouldii-Neptuneu tabulatu community, 24 (Conchocele), 24 bisecta; pl. 7 disjuncta, 7, 21,; pl. 7 folgeri, 7, 24; pl. 7 (Thyasim), 24 gouldii, 7, 21;; pl. 7 (Thyasim), Thyasira, 24 gouldii, Thyasim, 7, 24; pl. 7 Thyasim'dae, 1, 24, 25 Tierra Redondo Formation, 13, 33 tig’r’ina, Codakia, 11 Timms Point Silt, 25 Timms Point Silt Member, San Pedro Formation, 9, 12, 17, 24, 25, 28, 32, 33 Tomalas Bay, Calif,, 9 Topanga Canyon Formation, Topanga Group, 33 Topanga Formation, 10, 13, 17, 18, 27, 29, 33 Topanga Group, Topanga Canyon Formation, 33 Torrey Pines, 9 Tortugas Formation, 19, 33 Towsley Formation, 9, 11, 13, 17, 19, 33 lraski, Bruetia, 26, 28 Bmtial 7, 26; pl. 8 Diplodonta, 26 Tryon, G.W,, Jr., cited, 11 quoted, 11 Tumey Formation, 29, 33 Tumey(?) Formation, 24 Turcica caflea-Lucinama annulalu community, 24 Turner, F.E., quoted, 21 tumert', Claiborm'tes (Codalucina), 5, 20; pl. 7 Lucina, 20 Phacoides, 20 type specimens, 4 Holocene, 4, 5 U,V Umpqua Formation, 21, 32, 33; pl. 7 Unalaska Island, Alaska; pl. 11 undulata, Lucinopsis, 28 Ungulinidae, 1, 26, 28 unisulcalus, Diplodonta, 26 Diplodonta (Diplodimta), 7, 26; pl. 7 Terms, 26 United States, 19 southeastern, 31 southwestern, 31 Urruttia Canyon, Calif., 32 Vaqueros, 27 Vaqueros Formation, 13, 17, 18, 23, 27—29, 31, 33; pls. 3, 5, 6, 8, 9, 11 so-called, 23 Vaqueros horizon, 23 Vaqueros(?) Formation, 28 Vaqueros-Sespe Formations, undifferentiated, 18 Ventura County, Calif., 18, 26, 28, 32 Verrill, A.E., quoted, 21 Virginia, 16 viridis, Axinopsida, 7, 25; pl. 11 Axinopsis, 25 Vokes, H.E., quoted, 8, 21, 27 W Wagner, C.M., quoted, 16, 23, 24 Walnut Creek, Calif., 32 Waring, C.A., quoted, 18 Washington, 5, 7, 17, 24, 25, 29 wattsi, Lucina, 23 ”Luc'ina," 6, 23; pl. 11 Weaver, C.E., quoted, 17, 20 Weaver, D.W., quoted, 13 West Africa, 12, 26 West America, 31 West Indies, 11, 21 Wildcat Group, 17, 24, 25, 33 Woodford, A.0., quoted, 19, 21, 26 Woodring, W.P., quoted, 10 Wygal Sandstone Member, Temblor Formation, 13, 17, 18, 29, 33 X, Y,Z xantusi, Lucina (Miltha), 18 Miltha, 18, 19 (Miltha), 5, 18; pls. 5, 6 Phacoides, 18, 23, 24 (Miltha), 18 Yonge, C.M., cited, 5 (Zemysia) se’r’icala, Feloniella, 29 Diplodonta, 28 pacified, Diplodonta, 7, 28; pl. 8 Zinsmeister, W.J., quoted, 26, 28 l PLATES 1—11 l l l l l l [Contact photographs of the plates 1n this report are available at cost, from U. S. Geological Survey Library, ‘ Federal Center, Denver, Colorado 80225] FIGURES 1, 2. 3—6, 9, 12. 7, 8, 10, 11. 13, 15, 18. 14. 16, 17. PLATE 1 Lucina (Lucim'sca) menuda (Keen) (p. D9). Holotype CAS/SU 7526 (x3.0). Round Mountain Silt, Miocene. Lucina (Lucimsca) nuttallii nuttallii Conrad. (p. D9). 3, 6. Hypotype LAM 4639 (Hertlein and Grant, 1972) (x 1.5). San Diego Formation, Pliocene. 4, 12. Hypotype LAM 4640 (Hertlein and Grant, 1972) (x1.5). San Diego Formation, Pliocene. 5, 9. Hypotype UCMP 32835 (Durham, 1950) (x1.5). ISlas Coronados, Baja California Sur, Pleistocene. Lucina (Lucim'sca) nuttallii antecedents (Arnold). (p. D9). 7, 11. Hypotype LAM 4642 (Hertlein and Grant, 1972) (x20). San Diego Formation, Pliocene. 8, 10. Hypotype LAM 4641 (Hertlein and Grant, 1972) (x20). San Diego Formation, Pliocene. Anodontia? (Anodontia?) inflata (Wagner and Schilling) (p. D16). Holotype UCMP 11418. San Emigdio Formation, Eocene. Codakia (Codakia) distinguenda (Tryon) (p. D11). Hypotype UCMP 32874 (Durham, 1950) (x0.8). Islas Coronados, Baja California Sur, Pleistocene. Codakia (Epilucma) califomica (Conrad) (p. D11). Hypotype SDNM 04348 (Hertlein and Grant, 1972) (x20). San Diego Formation, California. Pliocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—D PLATE 1 17 LUCINA, ANODONTIA?, CODAKIA FIGURES 1-3. 4—6, 11. 12—15. 16. PLATE 2 Codakia. (Codakia) distinguenda (Tryon) (p. D11). 1, 3. Hypotype UCMP 32873 (Durham, 1950) (x08). Islas Coronados, Baja California Sur, Pleistocene. 2. Hypotype UCMP 32874 (Durham, 1950). Islas Coronados, Baja Califor- nia Sur, Pleistocene. Ctena (Ctena) mem'crma (Dall) (p. D12). 4. Hypotype UCMP 32838 (Durham, 1950) (x15). Islas Coronados, Baja California Sur, Pleistocene. 5. Hypoty'pe UCMP 32837 (Durham, 1950) (x 1.5). Islas Coronados, Baja California Sur, Pleistocene. 6. Same specimen as figure 5 (x3.0). 11. Same specimen as figure 4 (x30). Ctena (Ctena) Chiquita (Dall) (p. D12). Hypotype UCMP 32840 (Durham 1950). (x3. 0). Islas Coronados, Baja California Sur. Pleistocene. 8. Same specimen as figure 7 (x 1.5). 9. Hypotype UCMP 32840 (Durham, 1950) (x15). Islas Coronados, Baja California Sur, Pleistocene. 10. Hypotype UCMP 32841 (Durham, 1950) (x30). Islas Coronados, Baja California Sur, Pleistocene. Here (Here) hammi (Clark) (p. D12). 12. Holotype UCMP 30841 (x2.0). Markley Formation, Eocene. 13. Same specimen as figure 12 (x30). 14. Paratype UCMP 30842 (x30). Markley Formation, Eocene. 15. Same specimen as figure 14 (x20). Here (Here) ejfi'nger’l (Weaver and Kleinpell) (p. D13). Holotype CAS/SU 9285 (x20). Sacate and Gaviota Formations, undifferentiated. Eocene and Oligocene. CODAKIA, C TENA, HERE PROFESSIONAL PAPER 1228—D PLATE 2 PLATE 3 FIGURES 1, 2. Here (Here) eflmgeri (Weaver and Kleinpell) (p. D13). Holotype CAS/SU 9285 (x20). Sacate and Gaviota Formations undifferentiated. Eocene and Oligocene. 3, 4. “Lucina (Here) excavate temblorensis” Adegoke (p. D23). Holotype UCMP 36676 (x 1.5). Temblor Formation, Oligocene and Miocene. 5—14. Here (Here) excavata (Carpenter) (p. D13). 5. Hypotype SDNM 00133 (Grant and Gale, 1931) (x15). Fernando Formation, Pliocene and Pleistocene. 6. Hypotype LAM 4638 (Hertlein and Grant, 1972) (x 1.5). San Diego Formation, Pliocene. 7. Same specimen as figure 5 (x30). 8. Hypotype SDNM 00131 (Grant and Gale, 1931) (x40). Fernando Formation, Pliocene and Pleistocene. 9. Same specimen as figure 6 (X 1.5). 10. Hypotype LAM 4636 (Hertlein and Grant, 1972) (x20). San Diego Formation, Pliocene. 11-13. Lectotype of Lucina Mchthofe’ni Gabb ANSP 4492 (x20). Pico Formation, Pliocene and Pleistocene. 14. Hypotype of Lucina Mchthofeni Gabb (Loel and Corey, 1932) (x2.0). Vaqueros Formation, Oligocene and Miocene. 15, 16, 18, 20. Callucina (Callucma) lampra (Dall) (p. D10). 15, 18. Hypotype UCMP 32827 (Durham, 1950) Islas Coronados, Baja California Sur, Pleistocene. 16. Hypotype UCMP 32826 (Durham, 1950) (x 1.5). Islas Coronados, Baja California Sur, Pleistocene. 20. Same specimen as in figure 16 (x30). 17, 19. Callucina (Callucinu) lingualis (Carpenter) (p. D10). 17. Hypotype UCMP 32831 (Durham, 1950) (><1.5). Marquer Formation, Pliocene. 19. Hypotype UCMP 32833 (Durham, 1950) (x15). Marquer Formation, Pliocene. U‘S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—D PIATE 3 19 HERE, ”LUCINA”, CALLUCINA 20 FIGURES 1—3, 6. 4, 5, 16, 23, 27. 9, 15, 18. 10. 11. 12. 13, 14. 17, 19, 21, 22. 20, 24—26. PLATE 4 Lucinoma acutilimata (Conrad) (p. D16). 1. Hypotype (Moore, 1963) USNM 563233 (x20). Astoria Formation, Oregon. Miocene. 2. Hypotype (Moore, 1963) USNM 563232 (x20). Astoria Formation, Oregon. Miocene. 3, 6. Lectotype USNM 3519. Astoria Formation, Oregon. Miocene. Lucinoma annulata (Reeve) (p. D17). 4, 5. Hypotype (Hertlein and Grant, 1972) LACMP 4643. San Diego Formation, California. Pliocene. 16. Hypotype (Hertlein and Grant, 1972) LACMP 4644. San Diego Formation, California. Pliocene. 23, 27. Hypotype (Packard, 1918) CAS 9005. San Francisco Bay, Califor- nia. Holocene. . Pamilucina (Pamn'lucma) approximata (Dall) (p. D15). Hypotype (Durham, 1950) UCMP 32848. Comondli Formation, Baja California Sur. Miocene. Lucina? (Lucina?) diaboli (Dickerson) (p. D8). Holotype UCMP 11681 (x15). Martinez Formation, California. Paleocene. Lucina? (Lucina?) bramkamp’i Vokes (p. D8). Holotype UCMP 15629 (x3.0). Cerros Shale Member, Lodo Formation, California. Paleocene. Lucina? (Lucina?) quadrata (Dickerson) (p. D8). Holotype UCMP 11683 (x30). Martinez Formation, California. Paleocene. Pamn'lucma (Parvilucma) tenuisculpta tenuisculpta (Carpenter) (p. D14) Hypotype (Clark, 1915) UCMP 11572. San Pablo Formation, California. Miocene. Myrtea (Myrtea) tafltma (Dickerson) (p. D16). Holotype UCMP 11789 (x30). Cerros Shale Member, Lodo Formation, California. Paleocene. Parm'luct'na (Parm'luc'ma) tenuisculpta intensa (Dall) (p. D15) 17, 22. Hypotype (Hertlein and Grant, 1972) LACMP 4646 (x60). San Diego Formation, California. Pliocene. 19, 21. Hypotype (Hertlein and Grant, 1972) LACMP 4645 (x60). San Diego Formation, California. Pliocene. Linga (Pleurolucma) cancellam's (Philippi) (p. D14). 20, 24. Hypotype (Durham, 1950) UCMP 32867 (x60). Unnamed Pleistocene strata, Bahia Santa Inez, Baja California Sur. 25, 26. Hypotype (Durham, 1950) UCMP 32865 (x60). Unnamed Pleistocene strata, Bahia Santa Inez, Baja California Sur. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-D PLATE 4 LUCINOMA, PARVILUCINA, LUCINA?, MYRTEA, LINGA FIGURES 1—4, 12. 5, 7, 11. 6, 8, 9. 10. PLATE 5 Milthu (Miltha) xantusi (Dall) (p. D18). 1, 4. Hypotype (Grant and Gale, 1931) SDNM 001406. Pico Formation, California. Pliocene and Pleistocene. 2, 3. Hypotype (Durham, 1950) UCMP 32825. Unnamed Pleistocene strata, Islas Coronados, Baja California Sur. 12. Hypotype (G D. Hanna, 1926) UCMP 32285. Imperial Formation, California. Miocene or Pliocene. Miltha (Miltha) sanctaecmcis (Arnold) (p. D18). 5, 7. Hypotype (Loel and Corey, 1932) UCMP 31824. Vaqueros Forma- tion, California. Oligocene and Miocene. 11. Holotype USNM 165569. Vaqueros Formation, California. Oligocene and Miocene. Miltha (Miltha?) meganosensis (Clark and Woodford) (p. D19). 6. Holotype UCMP 31303 (x1.5). Meganos Formation, California. Paleocene. 8. Paratype UCMP 31305. Meganos Formation, California. Paleocene. 9. Paratype UCMP 31304. Meganos Formation, California. Paleocene. “Luc'ina” nasuta Gabb (p. D23). Holotype ANSP 4465 (x2). Tejon Formation, California. Eocene. U.S. GEOLOGICAL SURVE PROFESSIONAL PAPER 1228—D PLATE 5 MILTHA, ”LUCINA" FIGURES 1, 2. 3, 5,7. 6, 8. 10. 11. PLATE 6 Miltha (Miltha) xantusi (Dall) (p. D18). Hypotype (Grant and Gale, 1931) SDNM 00140a. Pico Formation, California. Pliocene and Pleistocene. Claibomites (Claibomites) diegoensis (Dickerson) (p.D20). 3, 5. Holotype UCMP 11788 (x1.5). Ardath Shale, California. Eocene. 7. Hypotype (Givens, 1974) UCR 4752/41 (x1.5). Juncal Formation, California. Eocene. Miltha (Miltha) parsom' Waring (p. D18). Holotype CAS/SU 150 (x 1.5). Martinez Formation, California. Paleocene. Claibomites (Codalucina) muirensis (Dickerson) (p. D20). Holotype UCMP 11682 (x2.0). Martinez Formation, California. Paleocene. Gibbolucma (Eomiltha?) packi (Dickerson) (p. D21). Holotype UCMP 11787 (x3.0). Tejon Formation, California. Eocene. Miltha (Miltha) sanctwecmcis (Arnold) (p. D18). Holotype USNM 165569. Vaqueros Formation, California. Oligocene and Miocene. Miltha (Miltha) xantusi (Dall) (p. D18). Hypotype (G D. Hanna, 1926) UCMP 32285. Imperial Formation, California. Miocene or Pliocene. U.S. GEOLOGICAL SURVE PROFESSIONAL PAPER 1228-D PLATE 6 MILTHA, CLAIBORNITES, GIBBOLUCINA FIGURES 1. 2, 7. 3, 8. 4, 21. 5, 6. 9. 10, 11, 13, 14. 12. 15, 17. 16, 18, 20. 19, 22. 23, 24. PLATE 7 Gibboluc'ma (Eomt'ltha) gyrata (Gabb) (p. D20). Holotype UCMP 11986. Tejon Formation, California. Eocene. Claiborm'tes (Codalucina) turmr’i (Stanton) (p. D20). Syntypes USNM 108971. Martinez Formation, California. Eocene. Myrtucma roseburgensis (Turner) (p. D21). 3. Holotype UCMP 33665. Umpqua Formation, Oregon. Eocene. 8. Hinge of holotype (x20). Thyasi'ra (Thyasira) gouldii (Philippi) (p. D24). Hypotype (Hertlein and Grant, 1972) LACMP 4652 (x60) San Diego Formation, California. Pliocene. Divaricella? (Egracina?) cumulata (Gabb) (p. D22). 5. Hypotype (Dickerson, 1915) CAS 258 (x30). Tejon Formation, California. Eocene. 6. Holotype UCMP 11988 (x60). Tejon Formation, California. Eocene. Thyasi'ra. (Conchocele) folgem' Wagner and Schilling (p. D24). Holotype UCMP 11434 (x 1.5). San Emigdio Formation, Eocene. Divalinga (Divalinga) ebm'nea (Reeve) (p. D22). 10. Hypotype (Durham, 1950, as Divam'cella lucasana Dall and Ochsner) UCMP 32422. Unnamed Pleistocene strata, Islas Coronados, Baja California Sur. 11, 14. Hypotype (GD. Hanna, 1926) UCMP 32289 (x 1.5). Imperial Forma— tion, California. Miocene or Pliocene. 13. Hypotype (Durham, 1950, as Diva’ricella. lucasana Dall and Ochsner) UCMP 32424. Unnamed Pleistocene strata, Islas Coronados, Baja California Sur. Lucina (Lucinisca) nuttallii antecedens (Arnold) (p. D9). Holotype USNM 165290 (x1.5). Careaga Sandstone, California. Pliocene. Diplodonta (Diplodonta) unisulcatus (V okes) (p. D26). Holotype UCMP 15636 (x30). Domengine Formation, California. Eocene. “Lucina” gaylo’rdi (Wagner and Schilling) (p. D23). Holotype CAS 6176 (X 1.5) San Emigdio Formation, California. Eocene. Thyasim (Conchocele) disjuncta (Gabb) (p. D24). Photocopy of Gabb (1868, pl. 7, figs. 48a, 48b). San Pedro Sand, Pliocene and Pleistocene. Thyasira (Conchocele) bisecta (Conrad) (p. D25). Holotype USNM 3518. Astoria Formation, Oregon. Miocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-D PLATE 7 GIBEOLUCINA, CLAIBORNITES MYRTUCINA THYASIRA DIVARICELLA? DIVALINGA LUCINA DIPLODONTA, ”LUCINA" FIGURES 1,6. 2—4. 11. 12-15. 16—20. 21, 25—29. 22—24. PLATE 8 Diplodonta (Diplodonta) cretacea (Gabb) (p. D26). 1. Photocopy of Gabb (1864, pl. 30, fig. 255). Meganos Formation, California. Paleocene. 6. Hypotype (Clark and Woodford, 1927) UCMP 31286 (x30). Meganos Formation, California. Paleocene. Axmopsida serricata (Carpenter) (p. D25). Lectotype USNM 5249 (x30). Photocopy of Palmer (1958, pl. 7., figs. 16—18. Puget Sound, Washington. Holocene. Bmetia? traskt' (Nelson) (p. D26). Holotype UCMP 30579 (x60). Martinez Formation, California. Paleocene. Diplodonta (Diplodonta) stephensoni Clark (p. D27). Holotype UCMP 11171 (x3.0). San Ramon Sandstone, California. Miocene(?). Diplodonta (Diplodonta) polita (Gabb) (p. D26). Holotype UCMP 11990 (x30). Martinez Formation, California. Paleocene. . Diplodonta (Diplodonta) buwaldoma Anderson and Martin (p. D27). 9. Paratype CAS 112 (x 1.5). Round Mountain Silt, California. Miocene. 10. Holotype CAS 111 (x 1.5). Round Mountain Silt, California. Miocene. Felaniella (Felaniella) parilis (Conrad) (p. D29). Holotype ANSP 4546 (x3.0). Astoria Formation, Oregon. Miocene. Diplodonta (Diplodonta) orbella (Gould) (p. D27). 12. Hypotype (Hertlein and Grant, 1972) LACMP 4648 (x30). San Diego Formation, California. Pliocene. 13, 14. Hypotype (Hertlein and Grant, 1972) LACMP 4649 (x20). San Diego Formation, California. Pliocene. 15. Hypotype (Clark, 1915) UCMP 11521 (x1.5) San Pablo Formation, California. Miocene. Diplodonta (Diplodonta) subquadmta Carpenter (p. D28). 16. Hypotype (Durham, 1950) UCMP 32398. Unnamed Pleistocene strata, Bahia Santa Inez, Baja California Sur. 17. Same specimen as Figure 16. (x3.0) 18. Hypotype (Durham, 1950) UCMP 32397 (x 1.5) Unnamed Pleistocene strata, Bahia Santa Inez, Baja California Sur. 19. Same specimen as Figure 18 (x30). 20. Hypotype (Durham, 1950) UCMP 32399 (x 1.5) Unnamed Pleistocene strata, Bahia Santa Inez, Baja California Sur. Felam'ella (Feltmiella) harfordt' (Anderson) (p. D29). 21. Hypotype (Loel and Corey, 1932) UCMP 31872 (x 1.5). Vaqueros For- mation, California. Oligocene and Miocene. 25, 29. Syntype CAS 63 (x15). Temblor Formation, California. Oligocene and Miocene. 26—28. Syntype CAS 62 (x15). Temblor Formation, California. Oligocene and Miocene. Diplodonta (Zemysma) paczfica Zinsmeister (p. D28). Holotype UCR 6682/100 (x20) Simi Conglomerate, California. Paleocene(?). PROFESSIONAL PAPER 1228-D PLATE 8 US. GEOLOGICAL SURVEY \ DIPLODONTA, AXINOPSIDA, BRUETIA?, FELANIELLA FIGURES 1—3. 11, 13, 14. PLATE 9 Feltmiella (Felamella) coma (Reeve) (p. D29). 1, 2. Hypotype (Hertlein and Grant, 1972) LACMP 4650 (x30). San Diego Formation, California. Pliocene. 3. Hypotype (Durham, 1950) UCMP 32396 (x2.0). Unnamed Pleistocene strata Bahia Santa Inez, Baja California Sur. Chama (Chama?) Sp. (p. D31). Hypotype (Loel and Corey, 1932) UCMP 31875 (x 1.5). Vaqueros Formation, California. Oligocene and Miocene. Miltha (Miltha?) jacalt'tosana (Arnold) (p. D19). Holotype USNM 165587. Etchegoin Formation, California. Miocene and Pliocene. Chama (Chama) echinata Broderip (p. D30). Hypotype (Durham, 1950) UCMP 30635 (x 1.5). Marquer Formation, Baja California Sur. Pliocene. . Chama (Chama) frondosa Broderip (p. D30). 8, 10. Hypotype (Durham, 1950) UCMP 30637. Marquer Formation, Baja California Sur. Pliocene. 9. Hypotype (Durham, 1950) UCMP 30636. Marquer Formation, Baja California Sur. Pliocene. Pseudochama (Pseudochama) exogyra (Conrad) (p. D32). 11. Hypotype (Durham, 1950) UCMP 32821. Marquer Formation, Baja California Sur. Pliocene. 13, 14. Hypotype (Durham, 1950) UCMP 32820. Unnamed Pleistocene strata, Islas Coronados, Baja California Sur. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—D PLATE 9 ‘ FELANIELLA, CHAMA, MILTHA, PSEUDOCHAMA FIGURES 1, 3, 5, 12. 2, 4. 6, 8—10. 11. 13. PLATE 10 Chama (Chama) squamuligera Pilsbry and Lowe (p. D31). 1, 3. Hypotype (Durham, 1950) UCMP 30640 (x 1.5). Marquer Formation, Baja California Sur. Pliocene. 5, 12. Hypotype (Durham, 1950) UCMP 30639 (x15). Marquer Formation, Baja California Sur. Pliocene. Pseudochama (Pseudochama) exogyra (Conrad) (p. D32). Hypoty'pe (Durham, 1950) UCMP 32822. Marquer Formation, Baja California Sur. Pliocene. Chama (Chama) frondosa Broderip (p. D30). Hypotype (Durham, 1950) UCMP 30636. Marquer Formation, Baja California Sur. Pliocene. Chama (Chama) drama Bernard (p. D30). 8, 9. Hypotype (Durham, 1950) UCMP 30638 (x08) Unnamed Pleistocene strata, Bahia Marquer, Baja California Sur. 6, 10. Hypotype (Hertlein and Grant, 1972) LACMP 4534 (x 1.5). San Diego Formation, California. Pliocene. Felamella (Felam'ella) cornea (Reeve) (p. D29). Hypotype (Durham, 1950) UCLA 32396 (x30). Unnamed Pleistocene strata, Bahia Santa Inez, Baja California Sur. Arcinella caltfomica (Dall) (p. D31). Holotype USNM 96452 (photocopy of Dall, 1903a, pl. 62, fig. 5). Off Isla Cedros, Baja California Norte. Holocene. U.S. GEOLOGICAL SURVE ‘ PROFESSIONAL PAPER 1228—D PIATE 10 CHAMA, PSEUDOCHAMA, FELANIELLA, ARCINELLA FIGURES 1, 12. 2—4. 6, 9. 7, 8, 11. 10, 14, 17—19. 13, 16. 15. PLATE 11 Chama (Chama) pellucida Broderip (p. D31). Hypotypes LACMP A8881.2. Iquique, Chile. Holocene. ”Lucina” wattsi Loel and Corey (p. D23). 2, 3. Syntype UCMP 31821. So-called Vaqueros Formation, Baja California Norte. Oligocene and Miocene. 4. Syntype UCMP 31822. So—called Vaqueros Formation, Baja California Norte. Oligocene and Miocene. Pseudochama (Pseudochama) exogyra (Conrad) (p. D32). Hypotype LACMP A8881 (x30). Catalina Island, California. Holocene. Axinopsida m'r’idis (Dall) (p. D25). Hypotype CAS 064842 (x 5.0). Unalaska Island, Alaska. Holocene. Pegophysema (Pegophysema) edentuloides (Verrill) (p. D21). 7. Hypotype (Durham, 1950) UCMP 32830a. Bahia Santa Inez, Baja California Sur. Pleistocene. 8. Hypotype (Durham, 1950) UCMP 32830b. Bahia Santa Inez, Baja California Sur. Pleistocene. 11. Hypotype (Durham, 1950) UCMP 32830a (x 3.0). Bahia Santa Inez, Baja California Sur. Pleistocene. Chama (Chama) arcana Bernard (p. D30). 10, 14. Hypotype LACMP A8888.1. Monterey, Calif. Holocene. 17, 18. Hypotype LACMP 1723. Newport Bay, Calif. Holocene. 19. Hypotype (Bernard, 1976) LACMP A8881.1. Monterey, Calif. Holocene. Adontorhina cyclia Berry (p. D25). Holotype CAS 61460 (x 7). Lomita Marl Member, San Pedro Formation. Pleistocene. Chama (Chama) echmata Broderip (p. D30). Hypotype LACMP A8881.6. Bahia Banderas, Mexico. Holocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—D PLATE 11 CHAMA, "LUCINA", AXINOPSIDA, PSEUDOCHAMA, PEGOPHYSEMA, ADONTORHINA ,ar;. GPO 585-045/9751 AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with the last offerings, are given in the current-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." 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WASHINGTON, D.C.--U.S. Department of the Interior Bldg, Rm. 2650, 1849 C St., NW. Maps Maps may be purchased over the counter at the U.S. Geological Survey offices where books are sold (all addresses in above list) and at the following Geological Survey offices: - ROLLA, Missouri--14001ndependence Rd. - FAIRBANKS, Alaska--New Federal Building, 101 Twelfth Ave. Tertiary Marine Pelecypods of California andBaja California: Erycinidae Through Carditidae By ELLEN JAMES MOORE PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—E UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1992 U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government Library of Congress Catalog-in-Publication Data Moore, Ellen James. Tertiary marine pelecypods of California and Baja California: Erycinidae through Carditidae / by Ellen James Moore. p. cm. — (Paleontology of California and Baja California) (U.S. Geological Survey professional paper; 1228—E) Includes bibliographical references and index. Supt. of Docs. no.: I 19.16: 1228—13 1. Bivalvia, Fossil—California. 2. Bivalvia, Fossil—Mexico—Baja California. 3. Paleontology—California Mexico——Baja California. I. Title. II. Series. III. Series: U.S. Geological Survey professional paper; 1228—E. QE811.M636 1992 564'.11'09794—dc20 92—3921 CIP For sale by the Books and Open-File Reports Section, U.S. Geological Survey, Federal Center, Box 25286, Denver, CO 80225 CONTENTS Page Page Abstract E1 Systematics: Pelecypods—Continued from Chapter D— Introduction 1 Continued Purpose and scope 1 Family Carditidae E11 Procedure 1 Genus Cardita 11 Acknowledgments 4 Subgenus Cardita ----------------------------------------- 11 Abbreviations 4 Subgenus Byssomera ----- 11 Systematics: Pelecypods—Continued from Chapter D -------- 5 Genus Strophocardia ------------------------------------------ 12 Family Erycinidae 5 Genus Cyclocardia 12 Genus Lasaea 5 Subgenus Cyclocardia ----------------------------------- 12 Family Kelliidae 6 Genus Glans 15 Genus Kellia 6 Subgenus Glans ------------------------------------------- 15 Genus Aligena 7 Subgenus Centrocardita -------------------------------- 15 Subgenus Aligena ----------------------------------------- 7 Genus Miodontiscus -------------------------------------------- 16 Genus Bomia 8 Subfamily Venericardinae ----------------------------------- 16 Subgenus Temblornia ----------------------------------- 8 Genus Venericardia --------- 16 Family Montacutidae 9 Subgenus Pacificor --------------------------------- 16 Genus Mysella 9 Subgenus Venericor -------------------------------- 25 Subgenus Rochefortia ------------------------------------ 9 Subfamily Carditesinae --------------------------------------- 26 Genus Thecodonta 9 Genus Glyptoactis ----------------------------------------- 26 Subgenus Pristes ------------------------------------------ 9 Subgenus Claibornicardia -- 26 Genus Neaeromya 9 Subfamily Thecaliinae ----------------------------------------- 28 Subgenus Orbitella --------------------------------------- 10 Genus Milneria -------------------------------------------- 28 Family Sportellidae 10 Fossil localities 28 Genus Basterotia 10 Geologic formations cited for occurrence of pelecypods ------- 29 Subgenus Basterotella ----------------------------------- 10 References 30 Index 35 ILLUSTRATIONS [Plates follow index] PLATE 1. Venericardia, Lasaea, Aligena, Kellia, Glyptoactis. 2. Venericardia. 3. Venericardia, Kellia, Bornia. 4. Venericardia, Thecodonta, Neaeromya, Cardita. 5. Venericardia, Glans, Miodontiscus. 6. Venericardia. 7. Cardita, Cyclocardia, Mysella, Glans, Glyptoactis, Cyclocardia. 8. Venericardia, Glyptoactis. 9. Cyclocardia, Venericardia, Basterotia, Cardita, Milneria. Page FIGURE 1. Divisions used in California for geographic range of species of pelecypods, Erycinidae through Carditidae --------------- E12 2. Divisions used in Baja California peninsula for geographic range of species of pelecypods, Erycinidae through Carditidae 3 3. Preliminary phylogenetic chart of Glyptoactis and Venericardia in the eastern Pacific prepared by LouElla Saul, Los Angeles County Museum of Natural History. 18 TABLES Page TABLES 1-3. Geologic and geographic distribution in the eastern Pacific region of the genera: 1. Lasaea, Kellia, Aligena, Bornia, Mysella, Thecodonta, Neaeromya, Basterotia, Cardita, and Strophocardia ------------ E5 2. Cyclocardia, Glans, and Miodontiscus 12 3. Venericardia, Glyptoactis, and Milneria 17 III PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA TERTIARY MARINE PELECYPODS OF CALIFORNIA AND BAJA CALIFORNIA: ERYCINIDAE THROUGH CARDITIDAE By ELLEN JAMES MOORE ABSTRACT The description of the mollusks in the Tertiary formations of California and Baja California is continued from Chapter D. Forty-eight species in the families Erycinidae, Kelliidae, Montacutidae, Sportellidae, and Carditidae, representing 15 gen- era, are covered in this chapter. Of the 15 included genera, 1 occurs in the Cretaceous, 2 in the Paleocene, 3 in the Eocene, 1 in the Oligocene, 3 in the Miocene, 11 in the Pliocene, 5 in the Pleistocene, and 12 in the Holocene of the included geographic area. Four genera are extinct or locally extinct. Venericardia (Pacificor) taliaferroi Verastegui was found by Verastegui (1953) to occur in the Late Cretaceous lower part of the Dip Creek Formation of Taliafero (1944) of Late Cretaceous and Paleocene age, thus extending the range of the genus Venericardia and the subgenus Pacificor into the Late Creta- ceous in the eastern Pacific. INTRODUCTION PURPOSE AND SCOPE The description and illustration of the Tertiary marine mollusks of California and Baja California started in Chapter A is continued in this chapter, which treats the families Erycinidae, Kelliidae, Montacutidae, Sportellidae, and Carditidae. A total of 48 species assigned to the included families occur in the geographic study area. For con- venience of reference, the figures showing the geo- graphic divisions used for the Californias are reproduced here (figs. 1, 2). PROCEDURE All Tertiary marine mollusks originally described from California and the Baja California peninsula, and all species originally described from other Manuscript approved for publication, September 24, 1991. geographic localities but known to occur in the Tertiary of the Californias, are included in this study. All positively identified species that have been found on faunal lists are also included. Only in genera that are extremely rare have I included species that are questionably identified. In this work, the species are arranged systemati- cally following the order of families, genera, and sub- genera given in the Treatise (Moore, 1969). Within the systematic groups, species are arranged by geo- logic age, beginning with the oldest species and end- ing with the youngest. Brief synopses of generic and subgeneric charac- ters are given in the appropriate places; more com- plete synopses will be found in the Treatise (Moore, 1969), in Keen (1971), and in Olsson (1961). Distribution tables are included to show graphi- cally the geographic and geologic distribution of spe- cies within each family. To facilitate finding a specific taxon, the species are listed alphabetically under genus and subgenus in the tables. The synonymy for each species includes the origi- nal citation and subsequent substantive references. The accuracy of identifications cited in subsequent references in the synonymy has not been verified. The type is usually that of the author of the original description or of later workers who selected a lectotype or neotype. If the original locality description is so vague that it is of little use, the type locality is described as corrected or modified by other workers such as Keen and Bentson (1944) and the modifications given within brackets. All other localities are cited as originally de- scribed except the formation name given is that Of the one currently being used. Previously published supplementary descriptions and comparisons are included, and I have supple- mented them in the section headed “Comments.” For most descriptions, my comments are based only on examination Of primary type material. E1 E2 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA 125° 1 20° 1 15° I I | 42° — NORTHERN + 0 50 100 150 200 KILOMETERS |____|_L__J_l § '0 ”E.” ‘> 5; O ._.. 'T\ .— O O O m .> E 2 Santa Cruz LOS ANGELES 34° ._ S San Miguel Island <3 $l m Santa Rosa Island ’_ ’— / / / Santa { am ‘ Catalin San Nicolas Island Q0 ll Island IMPERIAL San Clemente Island\ | SAN DIEGO FIGURE 1.—Divisions used in California for geographic ranges of species of pelecypods, Erycinidae through Carditidae. 32° 30° 28° 26° 24° TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE 116° 114° 112° 110° San Diego I ) I r I CALIFORNIA ‘3 Tijuana "—"_"_'7' ~\ ARIZONA E ~\‘ (/4, nsenada ‘\ . 1% u A7\~. 87‘ é\’\’I0\ £17119 <9 \~ ‘ ’7 ‘\~ (I ~ 7 0 \‘~ 0 . . ’7 San Qumtin (, ~ m 00 Rosario A O (. 5; m .2 O '7 1 Isla Angel 0 de la Guarda f; O «s 6‘ Bah/a \ ° lsla lsla Cedrosa Sebastian Tuburén " o Isla de Vizcol’no o - Natividad ‘ ‘ 07 '0 Bahia ( ° ‘ ‘y Tortugas f“ Santa (2‘ Rosalia ofi ,n Bahia 7* <9 Concepcion .5, § " Laguna '7 B 0 San Ignacio ‘fy ° 0 lsla Coronado 7 D O (I 1513 Carmen ‘ m 0 Isla Monserrate o o o (l vp m 00 7’ o z a . v 7 o lsla San Diego Isla San José Z lsla Magdalena 0" h C Bahia Ma da/ena ’3 \ 9 §% 6 mlsla Cerralvo La Pa: O 50 100 150 200 KILOMETERS I I I Cabo San Lucas I FIGURE 2.—Divisions used on Baja California Peninsula for geographic ranges of species of pelecypods, Erycinidae through Carditidae. E3 E4 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA All available published data for each species have been included in the section on geographic and geo- logic age range, including that contained in faunal lists when the identification is unqualified. Age ranges have not been refined within epochs. Where a stage name the same as a formation name is used (see fig. 3), it is placed in quotes to distinguish it from the rock unit. The divisions used here to indicate the approxi- mate geographic range of species within California based on county distribution are northern, middle, and southern (fig. 1); the divisions for the Baja Cali- fornia Peninsula, norte and sur (fig. 2) (tables 1-3). An attempt has been made to include all cita- tions to a species that are unqualified and every geologic formation in which it is reported to occur in the Californias. The assumption has been made that all identifications of species are correct unless there is strong evidence to the contrary. Under “Occurrence,” the author cited for a formation is the individual who named or cited the species and not the author who mapped or named the forma- tion. The stratigraphic nomenclature used herein is that of the author(s) cited and does not necessarily agree with that of the US. Geological Survey. The ages given for the stratigraphic units follow the classification of geologic time currently used by the US. Geological Survey (See “Geologic Formations Cited for Occurrence of Pelecypods” at end of pa- per), which does not necessarily agree with the the most recent revisions by workers outside the Sur- vey. Each formation listed is followed by the name of the author and date of publication of the work from which it was obtained. More than one refer- ence to a formation is given where it might be use- ful to the reader. The list of formations given for species occurrence should not be considered com- plete nor necessarily accurate. Many western American Tertiary faunas have not been included in a monograph, therefore, their species content is not fully known. It is hoped that the list of forma- tional occurrences reported will serve as a frame- work upon which the true distribution of each species can be built. The type specimens were all photographed by Charles L. Powell, II, of the US. Geological Survey. Owing to the fact that the specimens photographed were borrowed from other institutions, the usual technique of opaquing specimens for photography (Sakamoto, 1973) was not used. The holotype of each Tertiary species is figured if the type is extant. Holo- cene type specimens have generally not been figured; specimens considered to be of the same species by authors such as Durham (1950) and Hertlein and Grant (1972) are used for these illustrations, and this information is included in the plate explanation. Most of the data on habitat has been compiled from Abbott (1974), Bernard (1983), Hertlein and Grant (1972), Keen (1971), Morris and others (1980), Smith and Gordon (1948), Stanley (1970), and Yonge and Thompson (1976). ACKNOWLEDGMENTS John G. Vedder, of the US. Geological Survey, reviewed the stratigraphic occurrences of species, and his pertinent suggestions were most helpful. LouElla Saul, Los Angeles County Museum of Natu- ral History, reviewed the section on Venericardia, and Eugene Coan, Palo Alto, Calif, reviewed the section on Cardita and Cyclocardia; I am grateful for their generous assistance. LouElla Saul also gen- erously allowed me to publish her preliminary phy- logenetic chart of Glyptoactis and Venericardia, and I am indebted to her for this kindness. The following individuals made available or loaned type material, and I am indebted to them: Elana Benamy, Academy of Natural Sciences of Philadelphia, Frederick J. Collier and Jann W.M. Thompson, National Museum of Natural History, Thomas A. Deméré, San Diego Natural History Mu- seum, David R. Lindberg, University of California Museum of Paleontology, Robert Van Syoc, Califor- nia Acadamy of Sciences, and Edward C. Wilson, Los Angeles County Museum of Natural History. The late Mildred P. James made up cards for each species and its occurrences as noted on faunal lists. This was a time consuming task that she performed as a volunteer, and I am grateful to her for her pa- tience and support. ABBREVIATIONS AN SP: The Academy of Natural Sciences of Philadel- phia, Pennyslvania. BM(NH): British Museum of Natural History, Lon- don, England. CAS: California Academy of Sciences, San Francisco, Calif. CASG: California Academy of Sciences Geology, San Francisco, Calif. LACMP: Los Angeles County Museum of Paleontol- ogy, California. LAM: Los Angeles County Museum of Natural His- tory, California. MCZ: Harvard Museum of Comparative Zoology, Cambridge, Mass. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E5 TABLE 1.—Geologic and geographic distribution of the genera Lasaea, Kellia, Aligena, Bornia, Mysella, Thecodonta, Neaeramya, Basterotia, Cardita, and Strophocardia in the eastern Pacific Region [H=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; E=Eocene; Pa=Paleocene1 Alaska British Colum- bia Wash— ington Species Oregon California Central or South America Baja California Northern Middle Southem None Sur Genus Lasaea_ subviridis Dall ................................. Genus Kellia catacta Anderson and G D. Hanna lajollaensis M.A. Hanna ................. laperousii (Deshayes).... .. uvasana (Dickerson) ...................... Genus Aligena Subgenus Aligena diegoana Hertlein and Gram. ......... Genus Barm'a Subgenus Temblorm'a frankiana Henlein and Grant ......... triangulata (Anderson and Martin) Genus Mysella Subgenus Rocheforlia tumida (Carpenter) ......................... Genus Thecodonla Subgenus Pristes oblongus (Carpenter) ..................... Genus Neaeromya Subgenus Orbitella compressa (Dali) ............................ Genus Baslerotia Subgenus Basterotella hertleim' Durham ............................ Genus Cardita Subgenus Cardita superioris Waring ........................... Subgenus Byssomera affinis Sowerby ............................... Genus Strophocardia megastropha (Gray) ....................... CAS/SU: Stanford University, Stanford, Calif. [Stanford University collections are now in the California Academy of Sciences] SU: Stanford University, Stanford, Calif. UC: University of California, Berkeley. UCMP: University of California, Museum of Paleon- tology, Berkeley. UCLA/LACMP: University of California at Los Ange- les. [University of California at Los Angeles type collections are now in the Los Angeles County Museum of Paleontology] UCR: University of California at Riverside. USGS: US. Geological Survey, Washington, DC, Cenozoic locality register. USGS M: US. Geological Survey, Menlo Park, Calif, Cenozoic locality register. Ple to H P1 to H Ple to H H P1 to H P1 to H P1 to H PltoH P1 to H Ple to H USNM: National Museum of Natural History, Wash- ington, D.C. UW: University of Washington, Seattle. SYSTEMATICS: PELECYPODS—CONTINUED FROM CHAPTER D Family ERYCINIDAE Genus LASAEA Brown, 1927 Transversely rounded, minute, inflated, inequilateral, smooth, anterior side longest, beaks straight. Geographic range—Worldwide. . Geologic range—Eocene to Holocene (table 1). Habitat.—Intertidal, especially among Mytilus (Keen, 1971); intertidal to 10 m in the eastern Pacific (Bernard, 1983). E6 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Lasaea subm'ridis Ball, 1899 Plate 1, figures 2, 4 Lasaea rubra subviridis Dall, 1899, p. 881 [ex Carpenter MS]. Lasaea subviridis Ball, 1899. Keen, 1938, p. 29-30, pl. 2, figs. 1-6. Keen, 1971, p. 137, fig. 311. Original description.—“[L. rubra] variety subviridis Carpen- ter, is pale greenish yellow. It is reported from Lower Califor- ma.” Neotype.—CAS/SU 6053; CASG 65100 (Keen, 1938); syntypes USNM 75032. Coan (1977) believed the neotype designation of Keen (1938) to be invalid because Dall’s material was never properly searched. Type locality.—“Lower California” (Dall, 1899); Isla San Mar- tin, Baja California Norte (Keen, 1938); Bahia San Quintin, Baja California Norte (Coan, 1987). Holocene. Supplementary description.—“Shell minute, inequilateral (an- terior end longer), oblique, rather flat, greatest dimension par- allel to postero-dorsal margin, but not parallel to a line joining muscle-scars, beaks at posterior 2/5, umbones low (usually less than 1/10 the height of the shell); junction of anterior and ven- tral margins somewhat attenuated, ventral margin rounded, joining posterior in a smooth curve; colour greenish or yellowish grey, suffused with pink at the beaks, the colour sometimes ex- tending down into the ventral half of the shell, hinge tinged with pink; surface sculptured by irregular growth-constrictions and minute, wavy concentric striae, especially near the ventral margins; hinge of right valve with a lamellar (sometimes bifid) anterior lateral and nymph, a deep cardinal pit, and a lamellar posterior cardinal above the long, oblique resilium, hinge of left valve with two lamellar anterior laterals receiving the single lateral of the right valve, a thorn-like cardinal, and a small la- mellar posterior lateral.” (Keen, 1938) Comparison.—“Lasaea subviridis is distinguished from L. rubra by its greater size and the presence in the adult of wavy concentric sculpture, from Western Pacific species such as purpurata and scalaris by the wrinkling rather than pitting of the sculpture, and from L. cistula by its more oblique outline, its light colour, less tumid and lower umbones, and by the smooth slope of the anterior margin downward from the beaks. In dimensions, young specimens***are consistently longer than cistula of the same height; the height-length ratio of young subviridis is very similar to that of adult L. rubra.” (Keen, 1938) Geographic range.—Living: Northern California to Baja Cali- fornia Sur; fossil: southern California. Geologic range—Miocene and Pliocene. Occurrence in California.—Miocene and Pliocene: Capistrano Formation (Kern and Wicander, 1974). Habitat.-—Among the byssi of Mytilus along the uppermost edge of the mussel colonies (Keen, 1936); in kelp holdfasts (Smith and Gordon, 1948); intertidal to 10 m (Bernard, 1983). Family KELLIIDAE Genus KELLIA Turton, 1822 Ovate, slightly angular and strongly convex, with concentric striation. Geographic range—Worldwide. Geologic range—Eocene to Holocene (table 1). Habitat.—Intertidal to 50 m in the eastern Pacific (Bernard, 1983); often nestles in holes in rock (Hertlein and Grant, 1972). Kellia catacta Anderson and GD. Hanna Plate 1, figure 7 Corbula harrisi Dickerson, 1915, p. 42, 56, pl. 4, fig. 6. Dickerson, 1916, p. 420, 445. Kellia catacta Anderson and GD. Hanna, 1925, p. 171, pl. 2, fig. 6. New name for Corbula harrisi Dickerson not Corbula (Cu— neocorbula) swiftiana harrisi Dall, 1898. Original description.——“Shell small, thick, subtrigonal, with beak central, slightly prosogyrate; anterior dorsal slope slightly steeper than the moderately steep posterior dorsal slope; base broadly rounded; posterior end sharply rounded; a faint umbonal slope extending to the point between the posterior end and the base; shell decorated by faint radial ribbing which is strongest at posterior end along the umbonal slope and by concentric growth lines. Interior of shell is unknown and hence generic reference is doubtful. This species is not so thick as C. parilis Gabb and its concentric ribbing is not so strong.” Holotype.—CAS 275. Type locality.—CAS 244. Kern County, Calif. Tejon Formation, Eocene. Geographic range—Southern California. Geologic range—Eocene (table 1). Occurrence in California.—Eocene: (Dickerson, 1915). Tejon Formation Kellia uvasana (Dickerson) Plate 3, figures 9, 12 Corbula uvasana Dickerson, 1915, p. 42, 46, pl. 4, fig. 7. Dickerson, 1916, p. 420, 445. Kellia uvasana (Dickerson). Anderson and GD. Hanna, 1925, p. 172, pl. 2, fig. 7; pl. 9, fig. 11. Original description.—“Shell small, inflated with central beak, anterior dorsal margins slightly concave with moderate slope to a subtruncate anterior end; posterior dorsal margin with slight slope to a broadly rounded posterior; ventral margin broadly rounded. Faint radial lines and feeble concentric growth lines decorate this shell. Interior unknown. “Dimensionsz—Length, 7 mm.; height, 5 mm.; convexity, 2 mm.” Holotype.—CAS 276; CASG 244.04. Type locality.—CAS 244. Kern County, Calif. Tejon Formation, Eocene. Supplementary description.—“The shell is small, thin, ellipti- cal; surface smooth, except for small radial ridges extending from the umbones to the margins near the anterior and posterior ends, forming small marginal denticulations within.” (Anderson and Hanna, 1925, p. 172) Geographic range—Southern California. Geologic range.——- Paleocene to Eocene (table 1). Occurrence in California—Paleocene: Cerros Shale Member of Lodo Formation (Dickerson, 1916); Eocene: Tejon Formation (Dickerson, 1915). Kellia lajollaensis M.A. Hanna Plate 3, figure 8 Kellia lajollaensis M.A. Hanna, 1927, p. 284, pl. 37, fig. 7. Original description.——“She11 small, well inflated, subquadrate; ventral margin straight; posterior margin rounded to slightly truncated; anterior margin rounded; beak prominent, rounded, TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E7 nearly central; dorsal slopes on either side of the beak straight; surface ornamented on the posterior and anterior by rather prominent well-rounded ribs which are separated by concave interspaces of less width; concentric ornamentation consists of wide flat-topped ridges marked off by narrow lines; these concen- tric ridges distinctly overlap each other with the overlap toward the margin and not toward the beak; this overlap shows very well where the concentric ridges cross the radial ones, the con- centric lines bend toward the beak in crossing the radial ridges; no radial sculpturing present in the central portion of the shell; interior of the type not seen. Dimensions: Altitude 4.5 mm., length 6.5 mm., dorsal angle 117 degrees.” Holotype.—UCMP 31036. Type locality.—-—UC 3991. San Diego County, Calif. Rose Can- yon Shale of Hanna (1927), Eocene. Comparison.—“Kellia lajollaensis***most closely resembles Kellia catacta Anderson and Hanna, described by Dickerson as Corbula harrisi. However, Kellia lajollaensis has a different shape. The dorsal angle is greater and the ventral margin is straight. The new species differs much in sculpturing from ei- ther Kellia catacta or Kellia uvasana (Dickerson). The radial ridges on either extremity are more prominent, and the concen- tric sculpturing is different.” (Hanna, 1927) Geographic range—Southern California. Geologic range—Eocene. Occurrence in California—Eocene: Rose Canyon Shale (M.A. Hanna, 1927). Kellia laperousii (Deshayes) Plate 3, figures 10, 15 Chironia laperousii Deshayes, 1839, p. 357. Kellia laperousii (Deshayes). Arnold, 1903, p. 137, pl. 18, figs. 1, 1a. Oldroyd, 1924, p. 131, pl. 10, fig. 2; pl. 33, fig. 4. Yonge, 1951, p. 451-453, text fig. 1. Hertlein and Grant, 1972, p. 237, pl. 44, figs. 11, 19. Chironia suborbicularis (Montagu) variety laperousii Deshayes. Grant and Gale, 1931, p. 300, pl. 14, figs. 19a, 19b. Original description.——“Testa ovato transversa, subequilaterali, inflato turgida, laevigata; alba sub-epidermide viridi lutescente, umbonibus minimis, acutis, oppositis.” Holotype.—In the collection of the Laboratoire de Malacologie, Musée National d’Histoire Naturelle, Paris? (Hertlein and Grant, 1972, p. 237) Type locality.—No locality cited originally. Comparison—“Some of the small valves, about 3 mm long, from near the Mexican boundary, bear a close resemblance to K. suborbicularis Montagu, originally described from England. However, there is so much variation in shape in a series of Re- cent specimens of K. laperousii, some elongated, some subcircular, that we assign all the fossil valves in the present collections to that species. “The question as to whether this species is cosmopolitan or whether several closely related forms are involved has been dis- cussed by several authors. E.A. Smith [1902, p. 163] stated that shells of this species could not be separated with certainty from allied forms. More recently Soot-Ryen [1951, p. 31], in a discus- sion of Antarctic shells similar to K. suborbicularis, stated that the relationship of such forms is still unsettled but he suggested that probably a number of nearly related species are concerned in this problem. “None of the fossils from the San Diego Formation is as circu- lar in outline as the syntypes of the Recent west American K. laperousii chironi Carpenter illustrated by Palmer (1958, pl. 9, figs. 6—10}. “Kellia rotunda Carpenter was described as much larger than K. suborbicularis and nearly round in outline.” (Hertlein and Grant, 1972, p. 237) Geographic range.—Living: Bering Sea and Pribilof Islands to Isla Tiburon, Golfo de California; fossil: southern California and Baja California N orte. Geologic range—Pliocene to Holocene (table 1). Occurrence in California—Pliocene: Cebada Member, Careaga Sandstone (Woodring and Bramlette, 1950) and San Diego (Hertlein and Grant, 1972) Formation; Pliocene and Pleistocene: San Pedro Formation (Arnold, 1903); Pleistocene: unnamed strata near Los Angeles (Valentine, 1956; Kanakoff and Emerson, 1959), San Pedro Formation (Arnold, 1903), Newport Bay, and in San Diego (Arnold, 1903) and Baja California Norte (Valentine and Roland, 1969). Habitat.—Intertidally to 395 m (Hertlein and Grant, 1972); in- tertidally to 20 m in the eastern Pacific (Bernard, 1983). Genus ALIGENA Lea, 1843 Shell small, valves somewhat trigonal with the anterior end longer. Hinge plate very narrow, usually with a fingerlike tooth below the umbo in each valve, right-valve tooth slightly larger than the left, and a long oblique socket for the resilium ending in a widening of the hinge plate that simulates a posterior later- al tooth. Geographic range—Europe, Africa, North America. Geologic range.—Miocene to Holocene. Habitat.—In temperate and tropical waters, intertidally to 112 m (Hertlein and Grant, 1972); intertidally to 25 m in the eastern Pacific (Bernard, 1983). Inhabits relatively deep holes in rock made by borers, or empty shells such as mytilids, and is usually byssally attached (Y onge, 1951). Subgenus ALIGENA Subvertically pointed right cardinal tooth. Aligena (Aligena) diegoana Hertlein and Grant Plate 1, figures 6, 8-10, 12, 13 Aligena diegoana Hertlein and Grant, 1972, p. 235-236, pl. 44, figs. 1, 6; pl. 45, figs. 6, 7, 1o, 11, 13. Original description.-—“Shell roundly quadrangular, rather large for the genus, convex, the anterior is longer and narrower than the posterior end; beaks small, prosogyrate, situated a little posterior to the middle of the valves; lunular area gently depressed; anterior dorsal margin sloping moderately steeply to the anterior end which is rounded and slightly attenuated, pos- terior dorsal margin sloping gently downward and merging im- perceptibly into the broadly rounded posterior end, ventral margin very slightly rounded; exterior of valves sculptured only with lines of growth; hinge of right valve with a large, slightly twisted tooth beneath the beak, behind this a subtriangular, elongated ligamental pit; in front of the tooth there is an elon- gated depression which receives a projection of the opposite valve and fades out as a slight groove along the margin; hinge of left valve (paratype) with a large, tooth-like projection of the E8 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA lunular margin, behind this a very small cardinal lamella (lacking on some specimens) below the beak, and back of this the ligamental pit. Dimensions of holotype, a right valve, length 7.9 mm, height 6.1 mm, convexity (one valve), (approxi- mately) 2 mm.)” Holotype.—LACMP 4547. Type locality.—LAM 305. San Diego County, Calif. San Diego Formation, Pliocene. Supplementary description.—-“This species is represented in the present collections by more than 30 single valves. These vary in outline, some are more rounded in outline than others, and in some specimens the ventral margin is nearly straight. A broad, low, medial sulcus is present on some valves. “The cardinal tooth in the left valve of A. diegoana"*is re- duced to a thin lamella, or is absent on some specimens. The development of a tooth-like projection of the lunular margin which fits into a groove on the opposite valve appears to be compensatory for the reduction of the cardinal and augments the interlocking of the hinge area.” (Hertlein and Grant, 1972, p. 236) Comparison.—“The general outline of Aligena diegoana"*is somewhat similar to that shown in an illustration of a Recent specimen from off the west coast of Lower California which Harry (1969, fig. 16) referred to Aligena cerritensis Arnold. The type specimen of A. cerritensis is obliquely ovoid in outline. “The general shape of some valves of the new species is simi- lar to that of Aligena aequaia var. nuca Dall from Miocene stra- ta in Maryland‘". The new species also bears a resemblance to the east American Aligena laevis H. C. Lea which occurs in stra- ta of Miocene and Pliocene age. The west American species is more quadrate in outline and the hinge of the right valve appar- ently has a deeper, more trigonal ligamental pit.” (Hertlein and Grant, 1972) Geographic range—Southern California. Geologic range—Pliocene. Occurrence in California.—Pliocene: San Diego Formation (Hertlein and Grant, 1972). Genus BORNIA Philippi, 1836 Transversely trigonal to trapezoidal, slightly inequilateral, flattened; surface smooth, polished, or faintly ribbed and striat- ed. Ligament comprising a feeble external part, internal resilium without a lithodesma. Left-valve hinge with long, strong, poste- rior lateral tooth and a smaller, less distant anterior lateral to- gether with a small cardinal closely adjacent to it; right valve with strong lateral sockets and a small anterior cardinal socket. The shell of Bornia differs from that of Kellia in that the sur- face is radially striate or punctate, at least in part, lacks a periostracum, and has a narrower hinge with the posterior car- dinal of the left valve greatly reduced in size. Geographic range—Worldwide. Geologic range—Paleocene to Holocene. Subgenus TEMBLORNIA Keen, 1943 Short cardinals and shallow small resilium, so that posterior laterals, just behind it, look like cardinals; hinge plate straight under resilium. Resembling Bornia in outline, with radial sculpture on ante- rior and posterior slopes; differing from Bornia in the structure of the hinge; resilifer small and shallow, ventral margin of hinge plate entire, not bisected as in Bornia by the insertion of the resilium. Compared to Semeloidea, the lower margin of the hinge plate of Temblornia is more arched, the posterior cardinal is less curved and the radial riblets, externally, are more numerous and finer. Geographic range—North America, South America. Geologic range—Eocene to Pliocene. Bornia (Temblorm'a) triangulata (Anderson and Martin) Plate 3, figures 17, 18 Donax triangulata Anderson and Martin, 1914, p. 41, pl. 3, fig. 9. Bornia (Temblornia) triangulata (Anderson and Martin). Keen, 1943, p. 39, pl. 3, figs. 6, 7. Original description.—“Valves small, thin, trigonal, convex; beaks a little anterior to the middle; dorsal margins nearly straight; anterior extremity rounded; basal margin nearly straight; posterior end sharply rounded; an umbonal angulation extending from the beaks to the anterior and posterior extremi- ties, forming areas sculptured with six or seven radial ribs; left valve with one cardinal and two lateral teeth; ends crenulated within; muscular impressions indistinct.” Holotype.—CAS 130; CASG 65.02. Type locality.—CAS 65. Kern County, Calif. Round Mountain Silt, Miocene. Supplementary description.—"I‘he shell is of shining porcella- neous texture with six to eight faintly incised grooves at the an- terior and posterior ends. The grooves crenulate the inner margin slightly.” (Keen, 1943, p. 39) Geographic range.—Southern California. Geologic range—Miocene. Occurrence in California.—Miocene: Round Mountain Silt (Keen, 1943). Bornia (Temblorm'a) frankiana Hertlein and Grant Plate 3, figures l3, l4 Bornia (Temblornia) frankiana Hertlein and Grant, 1972, p. 238- 239, text fig. 11. Original description.—“Shell, a right valve, small, elongately trigonal, moderately inflated, nearly equilateral, slightly longer posteriorly; anterior and posterior margins nearly straight, near the ends rounding into the ventral margin; 10 rounded radial ribs on the anterior end just posterior to the margin and 7 simi- lar ones, somewhat flattened, on the posterior end, the ribs are faint dorsally but become gradually more strongly developed to- ward the ventral margin; ribs separated by interspaces which are a little wider than the ribs and in these, toward the ventral margin, lines of growth are accentuated (perhaps a result of ero- sion); remainder of the valve smooth except for somewhat irregu- lar lines of growth; hinge with 2 well developed cardinal teeth; interior of anterior and posterior ends of valve crenulated and slightly denticulated corresponding to the exterior sculpture. Length 6.5 mm, height 4.1 mm.” Holotype.—LACMP 4624. Type locality—LAM 305c. San Diego County, Calif. San Diego Formation, Pliocene. Comparison.—“Bornia (Temblornia) frankiana“*differs from the two other described species of Temblornia in its more TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E9 elongately trigonal outline and in the nearly straight anterior and posterior margins.” (Hertlein and Grant, 1972, p. 239) Geographic range—Southern California. Geologic range.—Pliocene. Occurrence in California.—Pliocene: San Diego Formation (Hertlein and Grant,1972). Family MONTACUTIDAE Genus MYSELLA Angas, 1877 Shell triangularly ovate, anterior end longer, sculpture concen- tric; left valve with a large, diverging, flattened tooth posterior to the triangular resilifer; anterior margin of resilifer thickened and margined to simulate a transverse tooth; in front of this is a small socket; right valve with hinge margin on each side of umbo produced, which is overlapped by the hinge line of the op- posite valve; the posterior toothlike edge interlocks above the cardinal tooth of the left valve and, the anterior which is shorter, is received in the socket in front to the ridgelike edge of resilifer. These toothlike margins of the right valve represent cardinal rather than lateral teeth. Geographic range.—Worldwide. Geologic range—Miocene to Holocene. Habitat.—2 to 97 m in the eastern Pacific (Bernard, 1983). Subgenus ROCHEFORTIA Velain, 1877 Shell more or less rounded at both ends. Resilium with crests as bifid tooth. Differs from Mysella in having a stouter, shorter chondrophore with minute crest at its top on right valve and in having crests on the resilium. Geographic range—Indian Ocean, Australia, North America. Geologic range.-—Pliocene to Holocene. Habitat—5 to 120 m in the eastern Pacific (Bernard, 1983). Mysella (Rochefortia) tumida (Carpenter) Plate 7, figures 5, 6 Tellimya tumida Carpenter, 1864, p. 602, 611, 643. Mysella tumida (Carpenter). Dall, 1899, p. 881, 892, pl. 87, fig. 7. Palmer, 1958, p. 88, pl. 7, figs. 8-12. Abbott, 1974, p. 473, fig. 5447. Mysella tumida Carpenter. Hertlein and Grant, 1972, p. 239- 240, pl. 44, figs. 2-5, 7, 8, 12. Mysella cf. M. tumida (Carpenter). Addicott, 1966, p. C4, pl. 4, figs. 12, 13. Original description.—“Between [Mysella] bidentata and substriata: ossicle minute.” Holotype.—USNM 5242. Type locality.——Puget Sound, Kennerley, Wash. (Palmer, 1958). Holocene. Supplementary description.——“*“moderately compressed, somewhat triangular in shape. The tiny beaks are almost at the posterior end. The hinge teeth are large in comparison with other species.” (Abbott, 1974, p. 473) Comparison.—“The species described by Dall as Mysella pe- droana is elongate in outline but the hinge was described as 'feeble'. The illustration of the type shows the hinge to be quite different from that of M. tumida.” (Hertlein and Grant, 1972, p. 240) Geographic range.—Living: Shumagin Islands, Alaska, to Laguna Scammon, Baja California Sur; fossil: middle California to Baja California N orte. Geologic range—Pliocene to Holocene. Occurrence in California: Pliocene: Graciosa Member, Careaga Sandstone (Woodring and Bramlette, 1950) and San Diego For- mation (Hertlein and Grant, 1972); Pleistocene: unnamed strata at Point Afro Nuevo, San Mateo County, Calif. (Addicott, 1966) and at Bahia San Quintin, Baja California Norte (Hertlein and Grant, 1972). Genus THECODONTA A. Adams, 1864 Transversely rounded, convex, very inequilateral, posterior part much elongated. Sculpture concentric. Anterior left lateral curved, gradually increasing subparallel to margin, then straightened along oblique resilium. Posterior laterals remote, thickened. Subgenus PRISTES Carpenter, 1864 More transverse than oblique, with scarcely projecting beaks and arcuate anterior, transversely serrated laterals; duplicate subparallel left posteriors. Geographic range.—-California. Geologic range—Pliocene to Holocene. Thecodonta (Pristes) oblongus (Carpenter) Plate 4, figures 3, 4 Pristes oblongus Carpenter, 1864, p. 611, 643. Palmer, 1958, p. 89, pl. 9, figs. 11-13. Hertlein and Grant, 1972, p. 240- 241, pl. 44, figs. 9, 10, 13, 14. Original description—“Like Tellimya, with long marginal teeth, serrated near hinge.” Lectotype.—USNM 15592 (Palmer, 1958). Type locality.-—San Pedro, Calif. (Palmer, 1958). Holocene. Supplementary description.—"3 to 5 mm., quadrate, resem- bling a Nucula in shape, with the umbones at the anterior trun- cated end. Dorsal margin arching, below it one of the long cardinal teeth is serrated. Posterior end somewhat pointed. Lunule small and concave." (Abbott, 1974) Geographic range—Living: Monterey, Calif. to Baja California Sur; fossil: Southern California. Geologic range—Pliocene to Holocene. Occurrence in California..—P1iocene: San Diego Formation (Hertlein and Grant, 1972); Pleistocene: Unnamed strata at Crown Point, San Diego (Valentine (1959). Habitat.—Occasionally found living commensally under the girdle of the chiton Stenoplax conspicua (Pilsbry). (Morris and others, 1980) Genus NEAEROMYA Gabb, 1873 Transversely subquadrangular to trigonal, finely striated. Right strong anterior laminar tooth and oblique posterior en- larged margin; oblique resilium between them; left thinner ob- lique anterior. E10 Geographic range—Central America, North America, Europe. Geologic range—Pliocene to Holocene. Subgenus ORBITELLA Dal], 1900 Anterior margin broadly rounded, elongate, thus very inequilateral. Geographic range.——United States: Florida and Alaska to Mexico. Geologic range—Miocene to Holocene. Habitat—0 to 50 m in the eastern Pacific (Keen and Coan, 1974). Neaeromya (Orbitella) compressa (Dall) Plate 4, figures 5, 7 Erycina (Pseudopythina) compressa Dell, 1899, p. 888, pl. 87, figs. 1, 8. Pseudopythina compressa (Dall). McGinitie, 1959, p. 173, pl. 19, figs. 2, 3, 5. “Orbitella”compressa (Dall). Roth, 1979, p. 293—294, pl. 3, figs. 6, 7. Original description.—“Shell large, subquadrate, thin, moder- ately compressed, white, covered with a conspicuous, thin, wrin- kled, partly glossy periostracum; nearly equilateral, the posterior end slightly broader, both ends rounded, the basal margin nearly straight; beaks inconspicuous, surface with strong, irregular incremental lines, but no radial sculpture; pal- lial scar rather wide and irregular, merging into the subequal, rather narrow adductor scars; resilium large, wide, and long, more or less calcareous ventrally, left valve with one obscure cardinal tooth, right valve with the tooth better developed; the right dorsal valve margins overlap those of the left valve a little, but there are no distinct lamella. Lon. 18, alt. 13, diam. 6 mm.” Holotype.—USNM 107855. Type locality.—“Dredged on muddy bottom in from 2 to 28 fathoms in the eastern part of Bering Sea, south of Nunivak Is- land, the eastern Aleutians, and southward to Sitka, Alaska.” Supplementary description.—“Keen and Coan (1974) and FR. Bernard (pers. comm.) suggest that the customary assignment of this species to Pseudopythina Fischer, 1878, is open to question. The hinge characters are approximately those of Orbitella, but the shell is unusually large for that genus. Among west Ameri- can bivalves, the most closely related species seems to be ‘Pseudopythina’rugifera (Carpenter, 1864), which in turn may have affinities to the genus Pythinella Dall, 1899, of the North American east coast and the west American tropics.” (Roth, 1979, p. 294) Geographic range—Living: Alaska to Mexico; fossil; northern California. Geologic range—Pliocene to Holocene. Occurrence in California.—Pliocene: Lower part of the Rio Dell Formation (Roth, 1979). Habitat.—0 to 50 m (Keen and Coan, 1974); 7 to 90 m on crus- taceans (Abbott, 1974). Family SPORTELLIDAE Genus BASTEROTIA Mayr in Homes, 1859 Shell small, subquadrate corbuliform, with a sharp carination running from the beak posteriorly. Valves convex, usually solid, PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA the beaks prosogyrate. Surface marked with fine concentric lines of growth and a sprinkling of fine or coarse granules. Liga- ment external, attached to a short, stout, plate-like nymph. Hinge with large, hook-shaped cardinal tooth in each valve, bor- dered behind or in front by a deep socket; the socket lies in front of the tooth in right valve and behind it in left. No pallial sinus. Geographic range—Worldwide. Geologic range—Miocene to Holocene. Habitat.—10 to 1,170 m (Hertlein and Grant, 1972); intertid- ally to 45 m in the eastern Pacific (Bernard, 1983). Subgenus BASTEROTELLA Olsson and Harbison, 1953 Like Basterotia in form, angled or carinate umbo, surface granulation and large, hook-shaped, subumbonal cardinal tooth, but differs in having both an internal and external ligament. Nymphal plate small and narrow, the resilial pit a small scar on its inner and lower face. Geographic range—Europe, North America. Geologic range—Miocene to Holocene. Habitat.—Intertidally to 45 m in the Galapagos Islands. (Bernard, 1983). Basterotia (Basterotella) hertleini Durham Plate 9, figures 8, l4 Basterotia hertleini Durham, 1950, p. 94-95, pl. 25, figs. 4, 11. Basterotia (Basterotella) hertleini Durham. Keen, 1971, p. 145, fig. 343. Bernard, 1983, p. 33. Basterotia californica Durham, 1950, p. 94, pl. 25, figs. 9, 13. Original description.—“Shell in general resembling B. peninsu- lare (Jordan) but more elongate and normally less inflated; subquadrate, moderately thin, ornamented by irregular concen- tric growth lines only; beaks not very prominent; an angulation running from umbo to posterior ventral margin; umbos situated about a fourth the length from the anterior end; a prominent projecting cardinal tooth in each valve, with adjacent deep ‘socket’ anterior to it in right valve.” (hertleini) “Shell small, moderately thin, elongate subquadrate, moder- ately inflated; ornamented by irregular concentric growth lines; beak not very prominent; an angulation running from umbo to posterior ventral margin; beak slightly anterior to midpoint of shell; a prominent projecting cardinal tooth in each valve, slant- ing anteriorly, a deep ‘socket’ adjacent posteriorly in left valve.” (californica) Holotype.—UCMP 32274; of californica UCMP 32668. Type locality.—Isla Carmen, Baja California Sur. Comondu Formation, Pliocene. Of californica, Bahia Santa Inez (27° N, 112" W). Unnamed Pleistocene strata. Supplementary description.—“The smooth shell is rounded anteriorly and posteriorly in the adult, with a weak ridge set- ting off the posterior slope; young shells are proportionately longer, more truncate posteriorly, with a sharper ridge.” (Keen, 1971, p. 145) Comparison.—“A growth series in the Stanford collection, dredged off the Mazatlan coast, bridges the difference in outline between B. californica and B. hertleini**"‘. At the southern end of the range the relative proportions change slightly, so that the shell seems shorter and higher; this is the B. ecuadoriana, which may prove to be a geographic subspecies.” (Keen, 1971, p. 145) TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E11 “This species may be distinguished from B. peninsulare (Jordan) by its greater length, greater width between the angulation and the posterior ventral margin, normally lesser inflation, and usually less sharp angulation.” (Durham, 1950, p. 95) Geographic range—Living: Baja California Sur to Ecuador; fossil: Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in Baja California Sun—Pliocene: Comondu and Marquer Formations (Durham, 1950); unnamed Pleistocene sedi- ments, Bahia Santa Inez (27' N, 112' W) (Durham, 1950). Habitat.—Intertidally, nestling in crevices and offshore to 46 m (Keen, 1971). Family CARDITIDAE Genus CARDITA Brug'uiére, 1792 Transversally inequilateral, trapezoidal or modioliform, with nodulose radial ribs. Hinge with obliquely trigonal divergent car- dinals in left valve and faint anterior laterals. Geographic range—Worldwide. Geologic range—Paleocene to Holocene. Habitat.—The carditids are shallow-water mollusks, many at- taching themselves under rocks by a byssus. (Keen, 1971) Subgenus CARDITA Relatively small, short; lunule not depressed. Geographic range—Europe, Africa, Asia, Australia, North America. Cardita (Cardita) superioris Waring Plate 4, figures 9, ll Cardita superioris Waring, 1917, p. 91. Original description.—“Shell small, very convex; beaks large, incurved; anterior end deeply excavated under the beaks; margin broadly rounded; basal margin broadly curved; posterior ob- liquely and convexly truncated; cardinal margin sloping and slightly convex; shell slightly concave near the cardinal margin and flared; surface ornamented by about 23 broad, slightly rounded ribs which are broader than the interspaces. A few casts of this species were obtained from the upper beds. Locality 8, L.S.J.U. Pal. Coll.” Holotype.—CAS/SU 143; CASG 61913.06. Type locality.—SU 2696. Ventura County, Calif. Llajas Forma- tion, Eocene. Geographic range.—Southern California. Geologic range.—Eocene. Occurrence in California.—Eocene: Llajas Formation (Waring, 1917). Subgenus BYSSOMERA Olsson, 1961 “Shell elongated, the posterior side generally wider, with a high, arched or vaulted umbonal angle extending from the beak to the posterior ventral margin, the posterior set of ribs strongly developed, the more anterior one often flattened to nearly obso- lete, the anterior-ventral side depressed. Hinge weak, the lateral teeth much reduced in size and more or less vestigial. Lunule small or absent.” (Olsson, 1961) Geographic range—Baja California Sur to South America. Geologic range—Pliocene to Holocene. Cardita (Byssomera) afi‘im’s Sowerby Plate 9, figures ll, 13 Cardita affinis Sowerby in Broderip and Sowerby, 1833, p. 195. Glans affinis (Sowerby). Grant and Gale, 1931, p. 278. Durham, 1950, p. 72, pl. 17, figs. 2, 9. Carditamera (Byssomera) affinis (Sowerby). Olsson, 1961, p. 189- 190, pl. 26, figs. 3-3d. Cardita (Byssomera) affinis Sowerby. Keen, 1971, p. 107, fig. 237. Original description.—“Card. testa oblonga, pallida, fusco- varid, latere antico brevi, postico elongato; costis paucis latis ra- diantibus, anticis obsoletiusculis, posticis prominentibus angulosis, subsquamigeris: long. 1.4, lat. 0.6, alt. 0.6 poll.” Holotype.—In Cummings collection. Type locality.—“Dredged from sandy mud, at a depth of from six to twelve fathoms, in the Bay of Montejo and Gulf of Nocoiya.” Holocene. Supplementary description.—“Shell elongate, rectangular, often large (length to 70 mm.), with the umbones and beaks placed between the anterior one-fourth and one-fifth, the anterior side, therefore, much shorter and narrower than the posterior. Dorsal and ventral margins long and fairly straight, subparallel, the anterior margin rounded, the posterior wider and subtruncate. The posterior umbonal slope is high and angular and usually more heavily sculptured. Sculpture formed by ribs, usually numbering about 17; of these, the six posterior ones and along the umbonal slope are large and usually coarsely scabrous, the others placed more anteriorly small and sometimes so low or flattened as to form smooth, colored radial rays. Hinge variable, the teeth sometimes much distorted and partly obsolete but when fully developed in the following form; the left valve has large, anterior cardinal tooth bordered on each side by deep sockets while the posterior cardinal tooth is a slender, narrow lamina separated from the nymph by a groove; the right valve has a large, slender cardinal tooth bordered in front by a deep socket; the left anterior tooth is small and placed close to the main cardinal.” (Olsson, 1961, p. 190) Geographic range—Living: Golfo de California to Peru; fossil: Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in Baja California Sur.—Pliocene: Comondu and Marquer Formations (Durham, 1950); Pleistocene: unnamed strata on Isla Carmen, Isla San Diego, Isla Coronado, and Golfo de California (Emerson and Hertlein, 1964). Habitat.—Living in close quarters as under stones and along narrow crevices (Olsson, 1961). Intertidally to 27 m on the Ga- lapagos Islands (Bernard, 1983). Subgenus STROPHOCARDIA Olsson, 1961 "Shell rounded cordate, solid, with high umbones and strongly prosogyrately coiled beaks over a small, deeply sunken lunule. Dorsal-posterior margin flattened, escutcheon-like. Sculpture formed by relatively few, low, rounded ribs. Hinge plate massive, the right valve with a large, stout, more or less hooked cardinal tooth, the left valve with two cardinal teeth and a large central socket; no vestigial laterals." (Olsson, 1961) Geographic range—Living: Gulfo de California to Ecuador and the Galapagos Islands; fossil: Baja California Sur. Geologic range—Pliocene to Holocene. E12 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA TABLE 2.—Geologic and geographic distribution of the genera Cyclocardia, Glans, and Miodontiscus in the eastern Pacific region [I-I=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; O=Oligocene; Pa=Paleocene] Species Alaska British Wash- Oregon California Baja California Colum- ington bia Northern Middle Southem Norte Sur Genus Cyclocara’ia Subgenus Cyclocardia barbarensis (Steams)... .............................. P1 [0 H .......... californica (Dan) .................................. M M [O Ple .......... crebricostata (Krause)... P1 to H H --------- P1 to Ple ----- P1 ---------- kirkerensis (Clark) ............................... O ............... montereyana (Arnold)... ......................... M ............... OCCidenlaliS (Conrad)... .............................. P1 to Ple .......... ventricosa (Gould)....... M to H M to H M to H M to H P1 to H H P1 to Ple H ----- Genus Glans Subgenus Glans subquadrata (Carpenter). ----- H H Subgenus Centrocardita veneriformis (Gabb) -------------------- Genus Miodontiscus prolongatus (Carpenter) M to H H H H H H PltoH Ple toH PletoH .......... Pa? ..... ..... ..... H H H Pl tOH .......... Cardita (Strophocardia) megastropha (Gray) Plate 7, figures 1, 2, ll, 14 Venericardia megastropha Gray, 1825, p. 137, two figs. p. 138. Cardita megastropha (Gray). Hertlein and Strong, 1946, p. 106. Durham, 1950, p. 71-72, pl. 16, figs. 6, 11. Cardita (Strophocardia) megastropha (Gray). Olsson, 1961, p. 187-188, pl. 26, figs. 5, 5a. Keen, 1971, p. 109, fig. 244. Original description.—“Testa oblique cordata crassa albida, rufo variegata, costis convexis rugosis; margine cardinali crassissimo. long. unc. New Holland? E. dono. Dom. Bennet.” Holotype.—BM(NH)? Type locality—Isla La Plata, Ecuador (Hertlein and Strong, 1946). Supplementary description—“Shell of medium or large size, solid, cordate, the ventral side rounded, the dorsal trigonal, with high umbones and strongly coiled beaks. The anterior-dorsal side is deeply impressed with a small, flattened lunule lying un- der and partially overhung by the beaks. Sculpture and appear- ance of specimens vary according to"*degree of wear***in beach specimens***; the ribs assume greater prominence and are seen to be low, trigonal in section, their interspaces also trigonal and with a central line***.” (Olsson, 1961) Geographic range—Living: Golfo de California to Ecuador and the Galapagos Islands; fossil: Baja California Sur to the Galapa- gos Islands. Geologic range—Pliocene to Holocene. Occurrence in Baja California Sur.—Pliocene: Marquer Forma- tion (Durham, 1950); Pleistocene: unnamed strata on Isla Coronado, Isla Monserrate, and Isla San Diego in Golfo de Cali- fornia (Emerson and Hertlein, 1964). Habitat.-—Offshore to 100 m (Keen, 1971); 30 to 150 m off the Galapagos Islands (Bernard, 1983). Genus CYCLOCARDIA Conrad, 1867 Subtrigonal or short trapezoidal to cordiform, ventral margin well rounded; regular radial ribs may be closely spaced, crossed by numerous equidistant growth lines; beaks very small, tending to be erect. Geographic range—Worldwide. Geologic range—Cretaceous to Holocene (table 2). Subgenus CYCLOCARDIA Juvenile-stage ribs narrow, rounded, equally perlate, later be- coming flattened and broadened, crossed by close-spaced growth lines; lunule large, smooth, slightly convex. Cardinal tooth on right valve of some species is bifid or grooved, but on other specimens this feature is faintly developed. Geologic range—Oligocene to Holocene (Hertlein and Grant, 1972). Habitat—1 to 2,210 m in the eastern Pacific (Bernard, 1983). Cyclocardia (Cyclocardia) kirkerensis (Clark) Plate 9, figure 12 Cardium kirkerensis Clark, 1918, p. 140, pl. 12, fig. 5. Original description.—“Shell small, inequilateral; beaks fairly prominent and rather strongly prosogyrous; anterior dorsal slope very slightly concave; posterior dorsal slope straight, about equal in length to the anterior slope; anterior and broadly and regular- ly rounded; posterior end broadly subtruncate, the lower angle of the truncation being obscure. Surface sculptured by from seven- teen to twenty V-shaped, nodose, radial ribs, with interspaces TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE averaging somewhat wider than the width of the ribs. Growth lines rather fine.” Holotype.——-UCMP 11165. Type locality.—UC 2033. Contra Costa County, Calif. Kirker Tuff, Oligocene . Geographic range—Middle California. Geologic range—Oligocene (table 2). Occurrence in California.-—Oligocene: Kirker Tuff (Clark, 1918). Cyclocardia (Cyclocardia) montereyana (Arnold) Plate 7, figure 21 Venericardia montereyana Arnold, 1908, p. 380-381, pl. 35, fig. 4. Original description.—“Adult shell attaining a length of at least 10 mm., width about three-fourths of length, suboval in outline, compressed; umbones near anterior extremity, small, turned toward the front; anterior extremity short, regularly rounded; posterior extremity long, obliquely projected below, quite sharply rounded; surface sculpture by about 22 moderately broad radiating ribs and numerous subequally spaced concentric lines, radiating and concentric systems together giving a cancellate appearance.” Holotype.—USNM 165464. Type locality.—Newell Creek, 2.4 km north of confluence with San Lorenzo River (SW1/¢, sec. 34, T. 9 S., R. 2 W), Santa Cruz quadrangle, Santa Cruz County, Calif. Monterey Shale, Miocene. Comparison.——“This species [C. montereyana] is probably allied to V. barbarensis Stearns and V. ventricosa Gould. It has more anterior umbones and has more numerous ribs (22 instead of 18) than the former, and is much flatter that the latter; its concen- tric sculpture is also more prominent than that in either of the recent species. Owing to the distortion of all the specimens of V. montereyana, it is impossible to say with certainty just what its original outline was, but it is believed to have been about as shown in the figured type.” (Arnold, 1908, p. 380-381) Geographic range—Middle California. Geologic range—Miocene. Occurrence in California—Miocene: Monterey Shale (Arnold, 1908). Cyclocardia (Cyclocardia) califomica (Dal!) Plate 7, figures 3, 4 Venericardia (Cyclocardia) californica Dall, 1903a, p. 1431, pl. 56, fig. 16. Cardita californica (Dall). Keen and Bentson, 1944, p. 119. Cyclocardia californica (Dall). Woodring and Bramlette, 1950, p. 85, pl. 8, fig. 16; pl. 10, figs. 7, 8; pl. 11, figs. 2, 3; pl. 15, figs. 1, 2; pl. 21, fig. 5. Durham and Addicott, 1965, pl. 5, figs. 16, 17. Original description—“Shell of moderate size, rounded-trigonal, somewhat inequilateral; beaks small, prosogyrate, dorsal slopes steep, the anterior shorter, base arcuate; sculpture of fourteen to sixteen radial, more or less beaded or nodulous stout ribs, those on the posterior slope smaller, smoother, and less distant; interspaces channelled, subequal to the ribs; the whole with transverse concentric, somewhat irregular elevated lines. All the sculpture more feeble towards the base; lunule small, lanceolate, smooth; hinge normal, interior basal margin with a few coarse crenulations. Length 24.0, height 21.5, diameter 14.0 mm.” Holotype.—USNM 164558. E13 Type locality.—“Pliocene(?) of California, five miles southwest of Guadalupe***,” Santa Barbara County, Calif. Santa Barbara Formation, Pliocene and Pleistocene. Supplementary description.—“This species [C. californica] is characterized by widely spaced coarse nodes. The nodes are sub- dued or absent toward the ventral margin of large shells and on a few shells they are subdued at an early stage‘". Arnold’s col- lection from the type locality shows a considerable range of vari- ation in outline and in the width of interspaces. The type is exceptionally elongate and has exceptionally wide interspaces.” (Woodring and Bramlette, 1950) Geographic range—Middle and southern California. Geologic range—Miocene to Pleistocene. Occurrence in the Californias.—Miocene: Pancho Rico Forma- tion (Durham and Addicott, 1965); Miocene and Pliocene: Sis- quoc (Woodring and Bramlette, 1950) and Towsley (Kern, 1973) Formations; Pliocene: Cebada and Graciosa Members, Careaga Sandstone, Comondu Formation (Durham, 1950), and Foxen Mudstone (Woodring and Bramlette, 1950), Marquer Formation (Durham, 1950) and San Diego Formation (Rowland, 1972); Plio- cene and Pleistocene: Fernando (Vedder, 1960), Santa Barbara (Dall, 1903b) and Saugus (Kew, 1924) Formations; Pleistocene: San Pedro Sand (Valentine and Meade, 1961) and unnamed strata on Isla Carmen and Isla San Marcos (Durham, 1950). Cyclocardia (Cyclocardia) occidentalis (Conrad) Plate 9, figures 3-6 C.[ardita] occidentalis Conrad, 1855, p. 267. 1857, p. 73, pl. 5, fig. 24. Cyclocardia occidentalis Conrad. Hertlein and Grant, 1972, p. 230-231, pl. 43, figs. 4-6, 9-11. Cardita monilicosta Gabb, 1861, p. 371. Venericardia borealis Conrad. Dall, 1874, p. 297. Not Venericardia borealis Conrad, 1831. Original description.——“Subtriangular, equilateral; ventricose; ribs 15, rounded, wider than the interstices, and regularly granulated by transverse lines.” (occidentalis) “Shell nearly circular; beaks small, submedian, cardinal border straight or faintly arcuate. Surface marked by from fourteen to seventeen large rounded ribs, strongly moniliform; interspaces narrow, acute. Posterior muscular impressions largest. Pallial line broad and distinct but not impressed. Internal margin coarsely crenulate, one large square tooth, corresponding with each interspace between the ribs; extreme edge undulated. Hinge robust. Length, 0.19 in.; width, 0.2 in.; depth of single valve, 0.05 in." (monilicosta) Holotype.—Missing and presumed lost (Woodring and others, 1946), of monilicosta unknown. Type locality.—Santa Barbara, Calif. (Conrad, 1857). Santa Barbara Formation, Pliocene and Pleistocene; of monilicosta, Santa Barbara, Santa Barbara County, Calif. Santa Barbara Formation, Pliocene and Pleistocene. Comparison.—Cyclocardia occidentalis has 14 to 17 radial ribs and dorsal-ventral elongation. Cyclocardia ventricosa has 18 to 20 radial ribs and anterior-posterior elongation. Geographic range—Southern California. Geologic range—Pliocene to Pleistocene. Occurrence in California.—Pliocene: San Diego Formation (Hertlein and Grant, 1972) and lower part of Saugus Formation (Squires and White, 1983); Pliocene and Pleistocene: Fernando (Arnold, 1907; Willett, 1946), San Pedro (Arnold, 1903), and Santa Barbara (Hertlein and Grant, 1972) Formations. E14 Cyclocardia (Cyclocardia) ventricosa (Gould) Plate 9, figures 9, 10 Cardita ventricosa Gould, 1850, p. 276. 1852, p. 417, atlas, p. 14, pl. 36, figs. 532, 532a. Grant and Gale, 1931, p. 272, pl. 13, figs. 9a, 9b, 11. Venericardia ventricosa (Gould). Oldroyd, 1924, p. 36, pl. 3, fig. 8. Cyclocardia ventricosa (Gould). Yonge, 1969, p. 494-505, figs. 1- 9, 19, 24a. Hertlein and Grant, 1972, p. 231, pl. 43, figs. 3, 8. Coan, 1977, p. 380-382, figs. 12-15. Roth, 1979, p. 295- 296,pl.4,fig.3. Original description.-——“’I‘esta solida, ventricosa, ovato-trigona vix obliqua, radiatim 18-20 costata, costis concentricé subnodo- sis, interstitiis angustis, epidermide fuliginoso, villoso induta; umbonibus submedianis, obtusis; intus alba; margine profunde crenulato; dente cardinali valvae dextrae, elevato, crasso, triangulari. Lat. 3/4; alt. 5/8; lat. 1/2 poll.” Syntypes.——USNM 3373. Type locality.—“Hab. Puget Sound.” Washington, Holocene. Supplementary description.—“The largest of four single valves***is a left valve 16.2 mm long and 15 mm high. There are 18 radial ribs of which the posterior 5 or 6 are smaller than the others.” (Hertlein and Grant, 1972) Comparison—“Compared with C.[ardita] borealis, Conr., it is thicker, less transverse, more tumid at the beaks, which are less recurved; the ribs are barred; the cardinal tooth is short, trian- gular (not long falcate) and detached from the margin; the crenulations of the margin deeper.” (Gould, 1850) “The shell of C.[ardita] ventricosa is more elongately (anterior- posterior) rounded [than Cardita occidentalis] and is sculptured with 18 to 20 rather than 14 to 17 radial ribs. “A Recent form from Monterey, California, more elongate (anterior-posterior) than usual for this species was named C. [ardita] ventricosa montereyensis by AG. Smith and Gordon. Inspection of a large series of specimens of this subspecies reveals that there are forms which imperceptibly grade into typical C. ventricosa. “A small southern form, more rounded in outline and more in- flated, with more sharply defined ribs, was described as C.[ardita] ventricosa redondoensis by J .Q. Burch." (Hertlein and Grant, 1972) Geographic range.—Living: Cook Inlet, Alaska, to Baja Califor- nia Norte; fossil: Washington to southern California. Geologic range—Miocene to Holocene; Graysian (molluscan) Stage in the Pacific Northwest (Addicott, 1976) Occurrence in California.—Pliocene: San Diego Formation (Hertlein and Grant, 1972); Pliocene and Pleistocene: Fernando (Eldridge and Arnold, 1907; Soper and Grant, 1932; Zinsmeister, 1970), Pico (Grant and Gale, 1931), San Pedro (Arnold, 1903), and Rio Dell (Roth, 1979) Formations; Pleistocene: Timms Point Silt Member, San Pedro Formation (Arnold, 1903) and unnamed strata in southern California (Grant and Gale, 1931) and New- port Bay area, California (Kanakoff and Emerson, 1959). Habitat.—20 to 628 m in the eastern Pacific (Bernard, 1983); 22 to 620 m (Coan, 1977); 14 to 574 m but more common in depths of 200 m or less on the southern California borderland (Jones and Thompson, 1987). Cyclocardia (Cyclocardia) crebricostata (Krause) Plate 7, figures 23, 24; plate 9, figures 1, 2 Cardita borealis var. crebricostata Krause, 1885, p. 30, pl. 3, fig. 5. Cyclocardia crebricostata (Krause). Coan, 1977, p. 378-379, figs. 6, 7. Roth, 1979, p. 297-298. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Cyclocardia (Cyclocardia) crebricostata (Krause). Bernard, 1979, p. 40-41, figs. 63, 64. Venericardia (Cyclocardia) alaskana Dall, 1903b, p. 710-711. {In- troduced for Venericardia borealis Conrad, 1890, in part.) Original description.—“Die Zahl der Rippen betragt 22-25; der Schlossrand ist dick, die Wirbel liegen central und sind nicht zerfressen; in der Nfihe der Wirbel sind die Rippen durch concentrische Furchen deutlicher und regelmassiger crenulirt als bei der vorigen. Die gitterartige Sculptur der Rippen ist wie bei der vorigen. Die grossere Schale zeigt folgende Maasse: long. 24, alt. 22, 1/2 crass. 6 1/2 mm.” (crebricostata) “This species is that which from the Pacific has usually been named V. borealis Conrad, and I can only ascribe the long accep- tance of this determination, made by Dr. Carpenter, to the ab- sence of a good series of the Eastern shell. After comparing them no one can hesitate to separate them specifically. There is a dis- tance of several thousand miles between their nearest points of approach to each other in range, as far as known. In a general way, until Dr. Stearns looked into the matter in 1890, all the Pacific Cyclocardias were lumped together under the name of bo- realis Conrad. “The present species is ovate, compressed, with 23-25 uniform and elegant radial ribs with narrower interspaces, distinct to the margin of the shell and covered with a dark yellow-brown vel- vety periostracum, the hairs in close radial lines. The ribs are slightly granular near the low beaks; the lunule narrow and long. The hinge is solid, with the right anterior and posterior cardinals nearly obsolete; the interior is chalky white and is fig- ured in the Proc. US. Nat. Mus., XIII, pl. XVI, fig. 8, under the name of C. borealis. It attains a height of 35, a length of 39, and a diameter of 16 mm. The animal is viviparous and incubates an enormous number of young shells until the adult sculpture is fairly initiated. The brood is fully ripe in August in the Arctic Sea, and about June 1 in the Aleutian Islands. The variability of the shell is chiefly in outline, some specimens being longer than others.” (alaskana) Lectotype.—Institut fur Spezielle Zoologie und Zoologisches Museum der Humboldt-Universitat, Berlin, 37934 (Coan, 1977); of alaskana USNM 109271 (Coan, 1977). Type locality.~Saint Paul Island, Bering Sea, Alaska. Holocene; of alaskana, Bering Sea, Alaska. Holocene. Supplementary description—“This variable species may be recognized by its large number of ribs (22 to 25) and its heavy periostracum with radially arranged hairs. Its hinge is long and narrow, and the shells are ovate and rather compressed.” (Coan, 1977,p.379) “Shell circular to nearly ovate, inflated, thick, maximum length 40 mm. Surface ornamented with 18—30 rounded ribs with equal interspaces crossed by numerous small concentric folds re- sulting in a scalariform appearance. Periostracum dark brown, velvety. Beaks small, erect, usually eroded. Interior polished, shell margins crenulated. Hinge delicate for the genus. Left valve with large central bifid cardinal and curved, elongated pos— terior cardinal tooth. Right valve with large central cardinal and thin laminar posterior cardinal tooth. External ligament placed on well-developed nymphs. Adductor muscle scars equal, deeply impressed. Pallial line impressed. No pallial sinus.” (Bernard, 1979) Comparison.—“This species is allied to the North Atlantic C. borealis (Conrad, 1831) but is distinguishable by the thinner shell, more delicate ribs, and weaker hinge." (Bernard, 1979) Geographic range.——Living: Alaska and southern Sakhalin; fos- sil: Alaska to southern California. Geologic range.—-Pliocene to Holocene. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE Occurrence in California—Pliocene: Lower part of the Rio Dell Formation (Roth, 1979) and lower part of the Fernando Forma- tion (Willett, 1946); Pleistocene: Elk River Formation (Roth, 1979). Cyclocardia (Cyclooardia) barbarensis (Steams) Plate 5, figures 9, 15 Venericardia barbarensis Steams, 1890, p. 214, pl. 16, figs. 3, 4. Oldroyd, 1924, p. 111-112, pl. 43, figs. 9, 11. Cardita barbarensis (Steams). Grant and Gale, 1931, p. 274. Cyclocardia barbarensis (Stearns). Woodring and others, 1946, p. 82-83, pl. 31, figs. 11, 12. Coan, 1977, p. 376-377, fig. 2. Original description.—“Shell rounded, inequilateral, variable in outline, more or less oblique, moderately convex. Beaks small, slightly elevated and turned forward. Surface ornamented with nineteen to twenty radiating ribs usually somewhat granulous, and generally obscure on the extreme anterior and posterior margins of the valves. Epidermis a dingy yellowish-brown, thicker toward the ventral margin and sides of the valves thin and commonly eroded at or toward the umbos. Lunule small, slightly sunken, faintly defined. Hinge line small, not thick; hinge composed of, in the left valve, a single strong cardinal sloping posteriorly and a smaller tooth often obscure, slanting anteriorly; a third tooth-like process is generally present, situ- ated under and apparently a projection of the edge of the lunule. This latter varies much in prominence in different specimens, and is often but barely perceptible. The hinge in the right valve is characterized by a single strong cardinal tooth with a slant- ing, somewhat sinuous groove above, and a slight notch and tooth-like point below the upper part of the lunule; this latter character is frequently inconspicuous and feeble. The valves are rather thin and somewhat translucent, bluish-white on the in- side and showing the ribs when held up to the light. Length, 15; height, 15; diameter, 11 mm.” Lectotype.—USNM 104045 (Coan, 1977). Type locality—Station 2840 off Santa Barbara, Calif. Holo- cene. Supplementary description.—“Shells of this species are thin, with 19 to 20 low ribs and a thin, dark periostracum.” (Coan, 1977) Comparison.—“This species [barbarensis] has much less prominent umbones, a thinner, more elongate hinge, and more ribs than [C.] ventricosa Gould. It appears to be closer to [C.] crebicostata (Krause) and may be a southern race of that north- ern species.” (Grant and Gale, 1931, p. 274) “Its [C. barbarensis] hinge is narrower than that of Cyclocardia uentricosa redondoensis; its beaks are smaller, and its shape more oblique.” (Coan, 1977) Geographic range—Living: Southern California; fossil: south- ern California. Geologic range.—Pl.iocene to Holocene. Occurrence in California.—Pliocene: upper part of Capistrano Formation (Kern and Wicander, 1974) and Lomita Marl Mem- ber, San Pedro Formation (Woodring and others, 1946); Pliocene and Pleistocene: Fernando Formation (Soper and Grant, 1932); Pleistocene: San Pedro and Santa Barbara Formations (Grant and Gale, 1931). [“Although reported from the Timms Point silt, San Pedro sand, and Palos Verdes sand***perhaps some of the records are based on worn specimens of C. aff. C. occidentalis.” (Woodring and others, 1946)] Habitat.—37 to 2,210 m in the eastern Pacific (Bernard, 1983). From 5 to 210 m, with some suggestion of deeper occurrence to E15 the south; on both sand and rocky bottoms (Coan, 1977). Broods its young (Jones, 1963). Genus GLANS Mergerle von Miihfeld, 1811 Shell bearing a general resemblance to carditids such as Carditamera but small, subquadrate in outline; hinge with well developed anterior and posterior laterals. Geographic range.—Asia, North and East Africa, Central America. Geologic range—Paleocene to Holocene. Habitat.—Intertidally to 100 m in the eastern Pacific (Bernard, 1983). Subgenus GLANS Truncate posteriorly, with nodulose or granular rounded ribs, posterior ones unequal in some species. Lateral teeth well devel- oped. Geographic range.—Europe, Asia, North and East Africa, North America. Glans (Glam) subquadrata (Carpenter) Plate 5, figures 10, ll Lazaria subquadrata Carpenter, 1864, p. 536, 627, 642. Glans subquadrata (Carpenter). Palmer, 1958, p., 82, pl. 7, figs. 1-4. Yonge, 1969, p. 505-509, figs. 10-13, 20-22. Hertlein and Grant, 1972, p. 232, pl. 43, figs. 16, 18, 19, 22, 30. Conn, 1977, p. 382-383, fig. 16. Glans minuscula Grant and Gale, 1931, p. 277, pl. 13, figs. 10a, 10b. [Unnecessary replacement name]. Original description.—"Hinge of Lazaria: outside like Cardita variegata juv." Lectotype.—-USNM 15681 (Coan, 1977). Type locality.—Monterey, Calif. Holocene. (Designated by Coan, 1977). Supplementary description.—"The outside of this remarkable little species is typically carditoid; the hinge is intermediate be- tween Lazaria and Cypricardia." (Carpenter, 1865, p. 178) "A minute left valve***has a well-preserved prodissoconch sculptured with strong concentric lamellae. Well-preserved minute Recent shells show the same prodissoconch sculpture." (Woodring and Bramlette, 1950) Geographic range—Living: British Columbia to Baja Califor- nia Sur; fossil: southern California to Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in California.—Pliocene: Cebada Member of the Careaga Sandstone (Woodring and Bramlette, 1950), San Diego (Hertlein and Grant, 1972), and lower part of the San Pedro (Grant and Gale, 1931) Formations; Pleistocene: unnamed strata in south- ern California and Baja California Norte and Sur (Jordan, 1926; Valentine, 1957; Valentine and Meade, 1961; Valentine and Ro- land, 1969), and on San Nicolas Island (Vedder and Norris, 1963). Habitat.—Intertidal zone to 91 m (Hertlein and Grant, 1972); intertidal to 100 m (Bernard, 1983). Almost all records are from rocky areas where the animal attaches itsef to rocks with a bys- sus (Coan, 1977). It broods its young (Yonge, 1969). Subgenus CENTROCARDITA Sacco, 1899 Posterior margin rounded, with equal squamose or echinate ribs. Hinge with almost obsolete small laterals. E16 Geographic range.-—Europe, East Africa, Australia, western North America. Geologic range—Eocene to Holocene. Glam (Centrocardita) venenformis (Gabb) Plate 7, figures 7-9 Cardita veneriformis Gabb, 1864, p. 215, pl. 32, figs. 285, 285a. Dickerson, 1914, p. 131. “Cardita” veneriformis Gabb. Stewart, 1930, p. 173, pl. 3, fig. 7. Glan[s] (Centrocardi[t]a) veneriformis Gabb, Zinsmeister, 1983, p. 63. Original description.—“Shell small, very convex, subquadrate; beaks rather large, strongly incurved; cardinal margin nearly straight; posterior end obliquely and convexly truncated; anterior end deeply excavated under the beaks, produced and narrowly rounded below; base broadly rounded; lunule broad, deeply im- pressed. Surface marked by about forty fine, acute, radiating ribs, with sometimes an intercalated one arising in the middle of the shell, and becoming as large as the others before it reaches the base; these are most numerous anteriorly, where all of the ribs are smaller than on the middle; margin strongly crenulated.” Holotype.—ANSP 4381. Type locality.—West of Martinez, Contra Costa County, Calif. Paleocene(?). Supplementary description.-—”The lunule is wide and im- pressed, the escutcheon is not preserved. There are six radial ribs to the two mm. interval on the central ventral margin. Some of the radial ribs near the anterior ventral border are ap- parently secondary and did not extend to the umbo. The liga- ment was opisthodetic. The hinge is unknown. Length, 9.8 mm.; height, 8.4 mm.; thickness of both valves, 7.5 mm.” (Stewart, 1930, p. 173) Geographic range—Middle California. Geologic range—Paleocene(?). Occurrence in California.—Paleocene(?): Martinez Forma- tion(?) (Dickerson, 1914; Stewart, 1930). Genus MIODONTISCUS Ball, 1903 Small, obliquely oblong, with strongly prosogyrate beaks and long, ill-defined lunule; sculpture of broad radial ribs crossed by concentric furrows. Geographic range—Western North America, Japan. Geologic range—Miocene (Japan) to Holocene. Habitat—9 to 128 m (Hertlein and Grant, 1972); 5 to 210 m in the eastern Pacific (Bernard, 1983). Miodontiscus prolongatus (Carpenter) Plate 5, figures 12-14, 16 Miodon prolongatus Carpenter, 1864, p. 611, 627, 642. Miodontiscus prolongatus (Carpenter). Palmer, 1958, p. 83, pl. 8, figs. 1-7. Hertlein and Grant, 1972, p. 233-234, pl. 56, figs. 1-5. Coan, 1977, p. 383-384, figs. 17-19. Venericardia yatesi Arnold, 1907, p. 439-440, pl. 58, figs. 2a. 2b. Original description.—”Outside Lucinoid; hinge and scars nearer to Venericardia. Congeneric with Astarte orbicularis, J. Sby. Min. Conch. pl. 444, f. 2, 3 (non ejusdem, pl. 520, f. 2). G. Oolite; and with the Crag Cardita corbis.” (prolongatus) “Shell averaging between 4 and 5 millimeters in altitude, sub- circular in outline, moderately convex. Beaks slightly posterior, PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA turned slightly forward, and somewhat prominent. Anterior mar- gin slightly depressed in front of beaks, but convex below this; anterior angle somewhat more sharply rounded than posterior, giving the valve an obliquely protruding appearance anteriorly. Posterior margin and base regularly rounded. The sculpture con- sists of 8 or 9 broad falcate ribs separated by narrow incised interspaces and several (8 in the type) very prominent concentric imbrications of growth; in addition to the latter are numerous fine incremental lines. Hinge relatively narrow for one of this genus.” (yatesi) Lectotype.—USNM 15472 (Coan, 1977); holotype of yatesi USNM 165248. Type locality—Neath Bay, Washington. Holocene; of yatesi Bath-house Beach, Santa Barbara, Santa Barbara County, Calif. Fernando Formation, Pleistocene. Supplementary description—“Typical specimens of Miodontis- cus prolongatus are about 5 mm in length and in height. They are trigonally subcircular in outline with rather prominent, erect beaks which are slightly curved anteriorly. The external sculp- ture consists of broad, low, radiating ribs and widely spaced con- centric, incised lines.” (Hertlein and Grant, 1972, p. 233) Geographic range—Living: Alaska to southern California; fos- sil: Russia, Alaska, and southern California. Geologic range—Pliocene to Holocene. Occurrence in California.—Pliocene: Cebada and Graciosa Members of the Careaga Sandstone (Woodring and Bramlette, 1950), Foxen Mudstone, Lomita Marl Member, of the San Pedro Formation, and San Diego Formation (Hertlein and Grant, 1972); Pliocene and Pleistocene: Santa Barbara Forma- tion; Pleistocene: Timms Point Silt Member, San Pedro For- mation (Woodring and others, 1946) and unnamed strata at Newport Bay, and on San Nicolas Island (Vedder and Norris, 1963), Calif. Habitat.—9 to 55 m (Hertlein and Grant, 1972); 5 to 210 m in the eastern Pacific (Coan, 1977; Bernard, 1983). Subfamily VENERICARDINAE Genus VENERICARDIA Lamarck, 1801 Rounded trigonal, inequilateral, thick-shelled, with numerous radial ribs evenly elevated at young stage but becoming flat- tened and enlarged on adults. Geographic range—Europe, Africa, North America. Geologic range—Late Cretaceous to Eocene (table 3). Geographic range—Europe, Africa, North America, New Zealand. Comments.—Fig'ure 3 shows the phylogeny of Venericardia in the eastern Pacific. Subgenus PACIFICOR Verastegui, 1953 Subtrigonal to rounded; immature ribs trifid, later becoming simple and rounded, nodulose to irregularly striated. The posterodorsal area in the left valve is smoother than in the right, has fewer ribs, and the ribs are weaker. Geographic range.—Europe?, North America. Geologic range—Late Cretaceous to Eocene. Comments.—Figure 3 shows the phylogeny of Paciflcor in the eastern Pacific. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E17 TABLE 3.—Geologic and geographic distribution of the genera Venericardia, Glyptoactis, and Milneria in the eastern Pacific region [H=Holocene; P1=Pliocene; E=Eocene; Pa=Paleocene; K=Cretaceous1 Wash— ington Species Oregon California Baja California Nonhem Middle Southern Norte Sur Genus Venericardia Subgenus Pacificor aragonia diabloensis (V erastegui) ......... aragonia joaquinensis (Vokes) ............. calafia calafia (Stewart) ...................... calafia gabbi (Verastegui) ................... calafia lutmani (Turner) ..................... calafia susanaensis (Verastegui) ........... clarki clarki Weaver and Palmer .......... clarki popenoei (Verastegui) ................ hornii (Gabb) ................................... mulleri Verastegui ............................ nelsoni Verastegui ............................ taliaferroi Verastegui ......................... Subgenus Venericor vallecitosensis (Vokes) ...................... venturensis (Waring) ......................... Genus Glyptoactis Subgenus Claibornicardia domenginica (Vokes) ......................... keenae (Verastegui) ........................... marksi (Verastegui) ........................... sandiegoensis (M.A. Hanna) ............... Genus Milneria minima (Dall) .................................. ..... Venericardia (Pacificor) taliaferroi Verastegui Plate 5, figures 3, 7, 8 Venericardia venturensis Waring. Taliaferro, 1944, p. 516. Not Venericardia venturensis Waring, 1917. Venericardia (Pacificor) taliaferroi Verastegui, 1953, p. 38-39, pl. 1, figs. 15, 16. Saul, 1986, p. 29, figs. 39, 40. Original description—“Shell small, convex, outline obliquely cor- date, anterior and ventral margins broadly rounded, the poste- rior obtusely truncate, the postero-dorsal somewhat arched; umbonal area convex; beak prosogyrate, curved forward, low, at about the anterior one-fourth. Posterior area depressed, slightly concave, characterized by finer ribbing. Sculpture (well preserved in the holotype) consisting of 20 to 22 ribs; the anteriormost 3 ribs V—shaped, the next 11 ribs tripartite with lateral terraces about one-fifth the width of the radials; ribs separated by U- shaped channels; the posterior 7 ribs V-shaped, the second from the last a little higher than the rest; interradials apparently ob- tusely V-shaped; with fine incrementals on the umbonal area, anteriorly coarsened to give the radials the appearance of being crenulated; periodic constrictions of growth (annual rings) well marked. Lunule impressed, slopes downward and forward. Hinge and interior of the types concealed by coarse matrix.” Holotype.—CAS/SU 7996; CASG 66526.01. Type locality.—NW‘/¢, NE‘A, sec. 30, T. 25 S., R. 10 13., V4 mile SSW [0.4 km] of Bench Mark 719, south of Williams Ranch on the Nacimiento River, Adelaida Quadrangle, San Luis Obispo County, Calif. Dip Creek Formation of Verastegui (1953), Upper Cretaceous and Paleocene. Comparison.—“Venericardia taliaferroi*"was originally misi- dentified as V. venturensis Waring. The round ribs and the typi- cal Pacificor distribution of fasciculate (terraced) ribs show that it is unrelated to V. venturensis which belongs to the subgenus Venericor***” (Verastegui, 1953). Geographic range.—Southern California. Geologic range.—Late Cretaceous to Paleocene. Occurrence in California.-—Upper Cretaceous and Paleocene: Dip Creek Formation (V erasteg'ui, 1953); Paleocene: basal part of San Francisquito Formation (Saul, 1986). E18 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA AGE STAGE PHYLOGENY uJ Z 8 2 O «‘6 _ Q m 'm -I ‘5 O "S M 9 I I I 2 I I .3 I I I I I ——-— cIarkI popenoeI B 3 I i: l .2 _ I2 hornII = clarki clarki I» L 'U 2 ‘ ~ - I 32 u ‘ ~ - LLI 2 L3 ‘ Z u: 8 marksI caIafI'a gabe' LLI =9 I crescentensls .E I I E’ E vallecitosensis o 9 domengim’ca I I I calafia caIafI'a I I I . l I '>\ I . I 2 g I I aragoma aragonla I IE ('3 sandiegoensis l I aragonia joaquInensIs ‘ I | ‘ ,l calafia IutmanI ‘ | I ~ ‘ ~ - ‘ , - v ’ ’ I 8 I I Y caIafIa snIsanaensIs g I , aragonla dIabloensis 6* | a) I I ‘ ~ ~ .2 I I ‘ ‘ ~ - ‘ I I I ‘ ~ - - I 2 — ? — I - ‘ ~ - .I I5 .J :N m g keenae muIIerl E "E I 0 ‘° I o — F 51.: I <1: _ 7 _ venturensls neIsonI ‘3' 2 I‘ I I I6 ‘3 I Lu E I I“ I: I I: D I 1 taII‘aferrol w 8 E e a *5 : 5 f5 8 e s U Subgenus (CIaIbornicardia) (Venericor) (Pacificor) Genus Glyptoactis Venericardia FIGURE 3,—Preliminary phylogenetic chart of Glyptoactis and Venericardia prepared by LouElla Saul, Los Angeles County Museum of Natural History. The species aragonia s. s. and crescentensis do not occur in the Californias but are found in Oregon and Wash- ington, respectively. Stage names in quotation marks distinguish them from formations of the same name. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE Venericardia (Pacificor) nelsom' Verastegui Plate 1, figures 3, 20 Venericardia planicosta var. venturensis Waring. Nelson, 1925, p. 403 [faunal list]. Not Venericardia venturensis Waring, 1917. Venericardia (Pacificor) nelsoni Verastegui, 1953, p. 21—22, pl. 2, figs. 1, 5; pl. 3, fig. 5. Zinsmeister, 1983, pl. 1, fig. 20. Saul, 1933, pl. 1, fig. 7. Venericardia (Pacificor) transversaria Verastegui, 1953, p. 37- 38, pl. 2, figs. 2-4. Original description.—“Shell large, heavy, ovate; outline smoothly rounded, umbo inflated, prosogyrate; the medial area defined by a sudden change of slopes on the anterior and poste- rior sides. Sculpture not well preserved in holotype; radials con- sisting of 22 rounded ribs which become obsolete toward the ventral border; umbonal sculpture in holotype lost by weather- ing; posterior area set off by five thin, crowded radials suc- ceeded by two outermost ribs which are conspicuously wider; interradials linear; incrementals moderately strong, crowded in senile stage and producing a conspicuous thickening of the bor- ders. Lunule of the left valve narrow, pointing downward and backward; pseudoescutcheon present, slightly concave, wide, bordered by a narrow ligamental groove; nymph long and nar- row; ligamental pit large, excavated in a prolongation of the nymph. Hinge plate heavy, low and short with a sinuous ven- tral margin; left anterior cardinal (2) long trigonal, obliquely set, posterior cardinal (4b) relatively thin, slightly broadening ventrally. Interior of holotype filled with matrix concealing the pedal and adductor muscle scars; crenulations on the inner margin not distinct.” (nelsoni) “Shell large, thick, inflated, outline subquadrate. Umbo prominent, strongly curved forward (unfortunately beak, lunule, and part of the hinge are broken in the holotype); anterior mar- gin broadly rounded, ventral margin gently curved, turning abruptly about 90' to the straight posterior margin. With typi- cal Pacificor sculpture modified by superimposed wrinkled lami- nations consisting of 22 ribs; the 6 anterior radials characterized by having lateral riblets not reaching the anterior margin; 4 of the 6 ribs on the posterior area thin, 2 marginal ribs wider. Interradials linear in the antero-medial portion, be- coming gradually wider and U-shaped in the posterior area. Pseudoescutcheon wide, concave, and distinct. Ligamental groove well developed. Hinge heavy, high, and short with a sinuous basal line; dentition not well preserved in the holotype, except the base of the massive and curved middle right cardinal (3b). Pedal muscle scar deep and large; adductor muscle scars deeply impressed. Shell conspicuously thickened at the postero» ventral point of the posterior scar; pallial line irregular, rather far removed from the margin; inner marginal crenulations very coarse.” (transversaria) Holotype.—UCMP 32804; of transversaria UCMP 32804A. Type locality.—UC 3765. Ventura County, Calif. Santa Susana Formation of Zinsmeister (1983), Paleocene; of transversaria UC 3765. Ventura County, Calif. Santa Susana Formation of Zinsmeister (1983), Paleocene. Comparison.—“V. mulleri has about 12 more ribs and***its lunule points downward and forward.” (V erastegui, 1953, p. 22) Geographic range—Southern California. Geologic range—Paleocene. Occurrence in California—Paleocene: Martinez (Verastegui, 1953) and Santa Susana (Zinsmeister, 1983) Formations. E19 Venericardia (Paaficor) mulleri Verastegui Plate 1, figures 1, 5, ll Venericardia (Pacificor) mulleri Verastegui, 1953, p. 20-21, pl. 2, figs. 1, 5; pl. 3, fig. 5. Saul, 1983, pl. 1, fig. 8. Venericardia mulleri Verastegui. Smith, 1975, p. 470, pl. 2, fig. 8. Original description.—“Shell of medium to large size, gently convex, rounded in outline with broadly arcuate anterior and ventral margins and obtusely truncate posterior margin; narrow pointed umbones and low prosogyrate beaks at the anterior fourth. Surface ornamentation consists of 32 to 34 well-defined ribs extending from the beak to the margin, 24 ribs on the antero-medial portion and approximately 10 on the posterior area; faint, terrace-like secondary riblets evident on both sides of the first 10 anterior ribs and receding to the posterior um- bonal area. Riblets one—fifth nearer the dorsal margin broaden away from the beak, and in the adolescent stage usually have one secondary riblet on the posterior side of the ribs; the re- maining seven ribs narrower, crowded, and cordlike; (beak areas poorly preserved in all specimens examined). Interspaces are V-shaped at the umbo but become shallower and less sharply angular in harmony with the rib crests which are sharp near the umbo and increasingly rounded ventrally. Growth lines present throughout, more apparent in the anterior area, where they intercept the crests of ribs and give the appearance of nodes. Pseudoescutcheon present. Lunule short and deep, slop- ing forward, distinctly convex, outlined by an incised groove, ending ventrally in a depression in the right valve. Ligament opisthodetic, nymph narrow and elongate; ligamental pit shal- low, elongate and bordered dorsally by an extension of the nymph. Hinge plate low, short, with ventral border distinctly sinuous; dentition of the right valve with a laminar anterior cardinal (3a) barely discernible on the posterior side of the lunular body, a medial obliquely cuneate cardinal (3b), and a slender posterior cardinal (5b). Pedal and adductor muscle scars not deeply incised. Pallial line entire and relatively far from the ventral margin. Crenulations of inner margin well marked in adolescent shell but obscure on a mature form.” Holotype: CAS/SU 7994. Type locality.—SU 2073. Fresno County, Calif. Base of Lodo Formation, Paleocene. Comparison—“V. argentea, a contemporaneous form, differs from V. mulleri by its pronounced umbonal convexity with fuller umbones, and by the somewhat flatter ribs in the adolescent shell. V. nelsoni***resembles V. mulleri in the general outline of the shell but is distinguished by having only 21 ribs. V. susanaensis***seems to be closely related to V. mulleri.” (Verastegui, 1953, p. 21) Geographic range—Middle and southern California. Geologic range—Paleocene. Occurrence in California.—Paleocene: Coal Canyon Formation and basal part of Lodo Formation (Verastegui, 1953; Smith, 1975). Venericardia (Pacificor) calafia susanaensis Verastegui Plate 1, figures 14, 16-18 Venericardia (Pacificor) susanaensis Verastegui, 1953, p. 22—23, pl. 5, figs. 1-4. Venericardia (Pacificor) hornii susanaensis Verastegui. Saul, 1983, pl. 1, fig. 14. E20 Original description.—“Shell, large, thin, outline rounded to subquadrate, not known in detail due to the fragmentary nature of the material; umbonal area narrow, slightly inflated; beaks prosogyrate, distinctly low and pointing forward. Sculpture of holotype well preserved; 22 ribs, persisting to the margins, in the antero-medial portion and 8 in the posterior area; earliest ribs worn away but that which remains shows that they are tri- partite and faintly beaded, at least in the anterior part of the shell; in the mature stage, the ribs of the antero-medial area rounded, those on the posterior area thin and crowded; the interradials V-shaped, reaching the ventral margin. Incremen- tals rough throughout the shell. Pseudoescutcheon narrow, con- cave, showing oblique lines of growth. Ligamental groove narrow; nymph thin and large, embracing anteriorly a linear ligamental pit. Hinge plate short and low with a sinuous basal margin, the sinuosity more pronounced in the right valve; denti- tion of arcuate-cuneate middle cardinal (3b), slightly concave on the wide basal margin, and a cordate posterior cardinal (5b) on the inner border of the nymph body; the left valve with a trapezoido-pyramidal, strong anterior cardinal (2), and a thin posterior left cardinal (4b), slightly thickened toward the ventral end. Interior of the holotype badly preserved; pedal muscle scars small and shallow, part of the shallowly incised posterior adduc- tor muscle scar visible, posterior adductor scar placed unusually far from the hinge plate. Inner margin strongly crenulate.” Holotype.—CAS/SU 8004; CASG 66527.01. Type locality.—-“SU CA-33, McCray Oil Wells, Oil Canyon, Camulos Quad, Ventura Co., California.” Uppermost Santa Susana Shale of Verastegui (1953), Eocene. Geographic range—Southern California. Geologic range—Eocene. Occurrence in California.—Paleocene and Eocene: Santa Susana Shale (Verastegui, 1953) Venericardia (Pacificor) aragom'a diabloensis Verastegui Plate 2, figures 8, 9; plate 5, figures 2, 5 Venericardia hornii Gabb, 11. var.?. Clark and Woodford, 1927, p. 92, pl. 15. Venericardia (Pacificor) diabloensis Verastegui, 1953, p. 27-28, pl. 5, figs. 5-7, 7a. Original description.—-“Shell large, slightly subquadrate, with inflated umbo and flattened ventral area; anterior margin broadly rounded, the ventral gently curved, and the posterior slightly truncate; beaks massive and curved forward, placed at about the anterior one-third. Umbonal sculpture consisting of 26 finely headed and in the anterior medial area laterally ter- raced ribs; on the posterior portion ribs cordlike, crowded and less distinct; adult sculpture characterized by 26 gently rounded, almost flat ribs separated by linear intercostals, ribs and intercostals gradually disappear with growth about 50 mm. from the beak, giving place to thick incrementals. Lunule con- vex, deeply inset, with lunular margin sloping almost vertically and ending in a pustule (in the left valve). Ligamental groove shallow. Hinge plate moderately high and long with a slightly sinuous ventral margin; nymph narrow but long; ligamental pit triangular, deeply incised. Dentition of the left valve consists of a scimitar-like, cuneate anterior cardinal (2), pointing toward and touching the lunular plate, with the inner face sloping uni- formly toward the ventral margin of the hinge, and a thin pos- terior cardinal (4b), also sloping. Interior of the type filled with matrix, concealing the pedal and adductor muscle scars. Inner margins crenulate.” PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Holotype.—CAS/SU 411; CASG 61967.01. Type locality.—“Marsh Creek, Brentwood, Contra Costa Co., California.” Meganos Formation, Paleocene and Eocene. Comparison .—“V. diabloensis closely resembles V. lutmani Turner from Oregon in outline but differs in having two less ribs than the latter.” (V erastegui, 1953, p. 28) Geographic range.—Middle California and Baja California Norte? (Flynn and others, 1989). Geologic range.—Paleocene and Eocene. Occurrence in Californias.—Paleocene(?): Bateque Formation (Flynn and others, 1989); Paleocene and Eocene: Meganos For- mation (V erastegui, 1953). Venericardia (Pacificor) calafia lutmam' Turner Plate 2, figures 1, 2; plate 4, figures 1, 12, 13; plate 5, figure 1 Venericardia hornii subsp. lutmani Turner, 1938, p. 50, pl. 13, fig. 4; pl. 14, fig. 2. Weaver, 1942, p. 135, pl. 28, fig. 1; pl. 32, fig. 1. Venericardia (Pacificor) lutmani Turner. Verastegui, 1953, p. 26- 27, pl. 7, figs. 305; pl. 8, fig. 8. Venericardia (Pacificor) homii lutmani Tamer. Givens, 1974, p. 47, pl. 1, fig. 16; pl. 2, fig. 8. Saul, 1983, pl. 2, fig. 6. Venericardia (Pacificor) durhami Verastegui, 1953, p. 23, pl. 7, figs. 1, 2. Flynn and others, 1989, p. 1,184, fig. 4 (4). ?Venericardia (Pacificor) diabloensis Verastegui. Flynn and oth- ers, 1989, p. 1,184, Fig. 4 (2A, 2B). Not Venericardia (Pacificor) diabloensis Verastegui, 1953. Original description.—“Shell heavy, subquadrate; beaks small; 27 ribs, the posterior 9 or 10 narrower and higher than the re- mainder, which are nearly obsolete with the exception of the an- terior three or four; lunule very short, deep; ligamental groove long, narrow.” “Shell large, thick, distinctly round in outline; umbones in- flated with the anterior slope more sharply curved than the pos- terior; beaks low, prosogyrate, situated at about the anterior one-third. Sculpture of 28 interradials, faintly represented over the main part of the disk; (sculpture on tips of beaks of holotype worn and not showing whether ribs are beaded or fasciculate); the antero-medial portion with 19 ribs and the posterior area with only 9, the 4 nearest to the dorsal margin being wider than the others. Lines of growth conspicuous over the greater part of the shell. Incrementals faint and smooth up to 25 mm. diameter becoming gradually coarser; dominating over obsolescent radial sculpture; a distinctive feature of the species. Lunule not well preserved, apparently small and deeply incised. Pseudoescutcheon narrow and concave. Hinge plate low and short; dentition in ho- lotype poorly preserved, traces of the cardinal (2) of the left valve, and the anterior cardinal (3a) of the right valve resemble those of Venericardia susanaensis, n. sp. Interior of holotype con- cealed by matrix.” (durhami) Holotype.—-UCMP 33133; of durhami CAS/SU 8005; CASG 66528.01. Type locality.——UC A-1233. Douglas County, Oreg. Umpqua Group, Roseburg Formation of Baldwin (1974), Eocene; of durhami “SU 829. 2.4 km W. of Vickers Hot Springs, Ventura Co., California.” Juncal Formation, Eocene. Supplementary description.——”Shell large, heavy, subquadrate in outline, anterior end evenly rounded, ventral gently curved, posterior truncate; umbones inflated, with low, pointed beaks situated at about the anterior one-fourth. Sculpture in holotype not well preserved; 20 ribs in the antero-medial portion; only 6 ribs preserved on anterior area, these show riblets which do not TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE reach the anterior margin; the visible intercostals linear; incrementals coarse and over-ride ribs in the anterior area but fine on the obsolescent ribs of the ventral area. Lunule small, convex, deeply inset, sloping downward and slightly forward, the right lunule three times as large as the left one. Pseudoescutcheon present, flat and wide (not well preserved). Nymph thin and large ligamental pit deeply incised. Hinge plate high and long, with a sinuous ventral margin. Dentition strong, consists of a laminar, long, nearly vertical anterior right cardinal (3a), pointed downward and slightly backward; a flat, scimitar-like, ventrally sinuous medial right cardinal (3b); a cordlike posterior right cardinal (5b) placed on a wide flat nymphal body; the left valve with a low, cuneate anterior cardi- nal (2), the upper end touches the lunular plate, and a thin, low posterior left cardinal (4b), not well preserved in the holotype. Pedal muscle scars shallowly incised; the rest of the interior of the shell concealed by the matrix.” (Verastegui, 1953, p. 27) Comparison.—“The new subspecies differs from V. hornii calafia Stewart in having three or four additional ribs. Speci- mens of the new subspecies from the Santa Susana shale of the Simi Valley region have 28 or 29 ribs and may be the initial form from which the later varieties or subspecies of V. hornii evolved by progressive elimination of ribs.” (Turner, 1938: 50) “This subspecies is distinguished from V. hornii by possessing 27 ribs and a low beak while the latter is characterized by 22 wide rounded closely spaced radial ribs. It differs from the sub- species calafia in having 3 or 4 more radial ribs. On the middle third of the shell the width of ribs is approximately two-thirds that of the interspaces.” (Weaver, 1942, p. 135) “This subspecies [lutmani] is similar in outline to V. hornii calafia, but is distinguished by a larger number (27-30) of radial ribs. As suggested by Turner (1938:50), V. hornii lutmani prob- ably evolved into V. hornii calafia by reduction in the number of ribs.” (Givens, 1974, p. 47) Geographic range—Southern Oregon, southern California, and Baja California Norte. Geologic range.—Eocene. Occurrence in the Californias.—Eocene: Bateque, Juncal, and basal part of Llajas Formations (LouElla Saul, written commun., 1989). Venericardia (Pacificor) calafia calafia Stewart Plate 3, figures 1-7, 11, 16, 19 Venericardia hornii subsp. calafla Stewart, 1930, p. 168-170, pl. 11, fig. 2. Turner, 1938, p. 50, pl. 14, fig. 4. Weaver, 1942, p. 134, pl. 28, figs. 6, 7; pl. 31, figs. 4, 5. Venericardia (Pacificor) calafia Stewart. Verastegui, 1953, p. 28-30. Venericardia (Pacificor) hornii calafia Stewart. Saul, 1983, p. 79, pl. 2, figs. 9, 16, 17. Squires, 1984, p. 46, figs. Mn, 0. Venericardia (Pacificor) oregonensis Verastegui, 1953, p. 25, pl. 9, figs. 7—9. Venericardia (Pacificor) hertleini Verastegui, 1953, p. 24-25, pl. 15, figs. 1, 2, 6. Venericardia hornii (Gabb), variety, Hanna, 1925, p. 286—287, pl. 38, fig. 4; pl. 40, figs. 1(?), 2. Original description.—“Shell large, heavy, almost circular, with small beaks: 24 radiating ribs on each valve, decorticated at the beaks, but a few of the anterior ribs still showing the lateral ridges and two of the posterior ribs of the left valve distinctly noded but apparently not ridged; on the central region, the ribs flatten and disappear when the shell is about 42 mm. long, as shown by the growth lines, the central area being quite smooth; E21 the anterior ribs gradually give way to prominent growth lines while the posterior ribs remain more or less distinct, but not prominent, to the posterior margin: hinge of type specimen not exposed. Length, 95 mm.; height, 86 mm.; thickness of both valves, 53.5 mm.; no. 31450, Museum of Paleontology.” (calafia) “Shell large, thick, broadly rounded, not strongly inflated; antero-ventral margin broadly rounded, the posterior slightly truncated. Umbo curved forward; beak placed at about the ante- rior one-third; posterior area flattened, somewhat concave and defined by a sudden change from coarse to fine ribs. Sculpture consists of 25 ribs which become obsolete near the margins. The 18 ribs in the antero-medial portion sharply angular on the beak, gradually become slightly flattened to the second annual ring then flatly rounded; the four or five ribs on the anterior area slightly terraced; those on the posterior area angular in the early stage become rounded later, the three ribs next to the gentle umbonal ridge thinner and crowded, and the last four near the posterior margin are much wider. Interradials U- shaped to the second annual ring, after which they become well- defined lines; interradials obsolete on the medial portion. Incrementals, fine on the umbonal area, coarse on the anterior, posterior, and on the marginal portions. Lunule of holotype small, trending downward and forward. Pseudoescutcheon pres- ent. Hinge plate low and long, with a conspicuous sinuous basal line; nymph thin and long; ligamental pit deeply incised and long. Dentition well preserved on the holotype, consists of an anterior left cardinal (2a), trapezoidal with a blunted upper end, and a posterior cardinal (4b), thin anteriorly but slightly broadening ventrally. Interior of holotype with normally incised pedal and adductor muscle scars; pallial line entire; inner mar- gins crenulated.” (hertleini) “Shell of medium size, thick, outline nearly circular; anterior, ventral and posterior margins evenly rounded, the postero-dorsal more gently curved. Shell moderately convex, with wide umbo, greatest convexity a little above the medial point of the disk; beak prosogyrate, distinctly low, placed at about the anterior one-third. Sculpture of 24 well-rounded ribs, (poorly preserved at the beak on the holotype), consisting of 16 wide, simple ribs in the antero-medial area becoming nearly obsolete below the middle of the disk, and 8 ribs on the posterior area—3 on the weak umbonal ridge, well defined and wide, 5 at the postero- dorsal margin thin, crowded, becoming obsolete 15 mm. beyond the beak; interradials present throughout except in the medial one—third of the marginal part of the shell; incrementals faint and crowded, but fairly strong ventrally; periodic growth stages (annual rings) marked by deep incisions. Lunule small, convex, deeply inset. Pseudoescutcheon and nymph not well preserved in the holotype. Hinge low and short with a distinctly sinuous ven- tral margin; dentition consisting of a small, laminar right ante- rior cardinal (33), a sharply triangular, curved medial cardinal (3b), and a thin right posterior cardinal (5b), not well preserved. Muscle scars and pallial line slightly incised; pedal scar some- what more stongly defined; pallial line entire, relatively far away from the ventral margin. Inner margin with unusually deep crenulations.” (oregonensis) Holotype.—UCMP 31450; of hertleini UCMP 30415; of or- egonensis CAS/SU 8009; CASG 66529.01. Type locality.—UC 7004. Ventura County, Calif. Llajas Forma- tion, Eocene. Of hertleini UC 3990, San Diego County, Calif. Rose Canyon Shale of Hanna (1927), Eocene. Of oregonensis “Bluffs along Little River at junction with North Umpqua River, Glide, Roseburg Quad, Douglas Co., Oregon.” Umpqua Group, Lookingglass Formation of Baldwin (1974), Eocene. E22 Supplementary description.—”Lunule convex, deeply inset, the right twice as large as the left; lunular groove trending down- ward and backward. Pseudoescutcheon well defined by a wide plate delimited by a grooved line on the dorsal side. Nymph long and narrow, somewhat slate at its posterior end, at the anterior it embraces a shallowly incised groovelike ligamental pit. Hinge plate high with a sinuous basal margin; dentition of the right valve consists of a strong plate-shaped, anteriorly slightly convex anterior cardinal (3a); a scimitar-like, strongly curved medial cardinal (3b), showing an incised groove in the upper part of the anterior face; and a long, thin, cordlike posterior cardinal (5b), the left valve has a high, curved, cuneate anterior cardinal (2), with an oblique cord in the upper part of the posterior face to correspond to the groove in 3b; and a thin, curved posterior car- dinal (4b) which slopes slightly at the ventral end. Pedal and adductor muscle scars shallowly incised, the posterior scar re- mote from the hinge; pallial line entire, rather near the margins. Inner margin faintly crenulated.” (Verastegui, 1953, p. 28-29) “V. hornii calafia is characterized by its circular to subquadrate outline and by the presence of 24 radial ribs***” (Givens, 1974, p. 47) Comparison.—“Stewart’s subspecies (calafla) differs only in small details from the rounded varieties of V. hornii (Gabb) found in the type Tejon. The anterior dorsal margin of the former is fuller, giving the beaks a lower appearance, and the ribs are slightly less rounded.” (Turner, 1938, p. 50) “V. lutmani Turner from the lower part of the Umpqua forma- tion appears to be ancestor of V. calafia. The two species differ somewhat in outline, V. lutmani being more subquadrate, but the pattern of the hinge is almost identical in both.” (Verastegui, 1953, p. 29-30) “The subspecies calafia resembles the species hornii in num- ber of ribs and ornamentation more than does the subspecies lutmani. The specimens of calafia from southwest Oregon have the radiating ribs less rounded than in the species hornii and the general outline of the shell is more orbicular than in the subspecies lutmani.” (Weaver, 1942, p. 135) Geographic range.—Southern Oregon and southern California. Geologic range.—Eocene. Occurrence in California.—Eocene: Llajas Formation (Keen and Bentson, 1944; Verastegui, 1953; Squires, 1984) and Rose Canyon Shale (Hanna, 1927). Venericardia (Pacificor) calafia gabbi Verastegui Plate 4, figures 2, 6, 8, 10 Cardita planicosta Lamarck. Conrad, 1855, p. 321, pl. 2, fig. 6. Not Cardita planicosta Lamarck, 1801. Venericardia hornii (Gabb). Hanna, 1925, p. 286-287, pl. 39, figs. 1, 2. Anderson and Hanna, 1925, p. 174, pl. 4, fig. 1. Venericardia (Pacificor) gabbi Verastegui, 1953, p. 30-31, pl. 19, figs. 1, 5, 6. Original description.—“Shell large, thick, subquadrate in out- line, the anterior margin broadly rounded, the ventral gently curved, the postero-ventral truncate, the postero-dorsal slightly arched. Umbo inflated, broadly convex, umbonal ridge inconspicu- ous but defined by a sudden change from coarse to fine ribs; beak prosogyrate, low, full, placed at about the anterior one- fourth. Sculpture consists of 23 ribs, 8 in the anterior area, wide, terraced and beaded in typical Pacificor manner; in the medial portion 6 ribs widen ventrally away from the umbo; in the poste- rior portion 9 narrow ribs, the 4 nearest the cardinal margin less distinct but wider; interradials on the beak channeled, becoming linear, and persisting to the margin except in the medial-ventral PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA area; incrementals fine in the umbonal area and coarse in the anterior and posterior portions. Lunule cordate, convex, anteri- orly trending downward and slightly backward. Pseudoescutcheon distinct, wide. Hinge plate low and long; nymph triangular, long; ligamental pit elongate, deeply incised; dentition consists of a laminar anterior right cardinal (3a); a scimitar-like medial cardi- nal (3b) with a wide base, elongate anteriorly; and a cordlike, short posterior right cardinal (5b) on a wide nymphal body. Inte- rior of the holotype concealed by matrix.” Holotype.—CAS 685; CASG 245.01. Type locality.—Grapevine Canyon, Kern County, Calif. Tejon Formation, Eocene. Supplementary description.-—“Venericardia gabbi is character- ized by its subquadrate outline and by its strongly convex umbo.” (Verastegui, 1953, p. 30) Comparison.—“It [gabbi] differs from V. hornii (Gabb) in its out- line, as the original Gabb specimen is elongate and obliquely ovate and V. gabbi has a quadrate outline accentuated by a sharp trun- cation on the posterior ventral margin.” (V erastegui, 1953, p. 30) Geographic range.—Southern California. Geologic range.—Eocene. Occurrence in California.———Eocene: (Verastegui, 1953). Tej on Formation Venericardia (Pacific-or) clarki clarki Weaver and Palmer Plate 5, figures 4, 6 Venericardia planicosta Lamarck. Arnold, 1907, pl. 38, figs. 1, 1a. Arnold, 1910, p. 13, pl. 2, fig. 1. Not Venericardia planicosta Lamarck, 1801. Venericardia planicosta hornii (Gabb). Waring, 1917, p. 95-96, pl. 11, figs. 3-5. Venericardia clarki Weaver and Palmer, 1922, p. 19, pl. 9, figs. 4, 5; pl. 10, fig. 8. Hanna, 1925, p. 287-288, pl. 36, figs. 3, 8; pl. 38, figs. 2, 3; pl. 43, figs. 1, 2; pl. 44, figs. 1, 2. Venericardia hornii subsp. clarki Weaver and Palmer. Turner, 1938, p. 49 (in part), pl. 14, figs. 3, 5. Weaver, 1942, p. 274, pl. 27, figs. 7, 9, 10, 17; pl. 33, fig. 6. Venericardia (Pacificor) weaveri Verastegui, 1953, p. 31, pl. 21, figs. 3, 4. Venericardia (Pacificor) lisa Verastegui, 1953, p. 39, pl. 21, figs. 1, 2. Venericardia (Pacificor) hornii (Gabb). Givens, 1974, p. 46, pl. 3, fig. 3. Original description.—“Shell small and ovate; umbones small; anterior end slightly produced, sloping from the beaks at an angle of 20', rounding into the ventral margin; ventral margin regularly rounded; posterior end rounded, passing from the ven- tral margin at about the same degree of convexity as the ante- rior end; surface ornamented with 18 to 20 very well developed radiating ribs with rounded interspaces about half the width of the rib; the median portion of the ribs is raised and rounded, the base forming a lower ridge on each side of the ribs, giving them a tripartite character; the median, raised portion of the ribs is ornamented by fine nodes or pustules which occur on all the ribs on very young shells, and on the umbonal region and the ante- rior end of most of the shells; the ribs on the posterior end of the older specimens become broader and the pustulate condition obliterated; inner margin fluted.” (clarki) “Shell large, thick, outline round to subquadrate, the anteri- or and ventral margins evenly rounded, the postero-ventral somewhat attenuate and the posterior margin slightly trun- cate. Umbo convex, inflated; umbonal ridge weak, ribs narrow- er on posterior slope; beak distinctly low, at about the anterior TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE two-fifths. Sculpture, characteristic of Pacificor, consisting of 21 rounded ribs relatively less perceptible in the ventral por- tion of the medial area; 14 ribs in the antero-medial area typi- cally fasciculate—tripartitely ribbed—showing a distinct nodose ornamentation near the beak and on rib crests; 7 ribs in the posterior area less prominent, thin and crowded. Inter- radials persistent to the margins, V-shaped on the beaks, be- come linear in the rest of the shell. Incrementals fine on the disk, coarse on the anterior portion. Lunule cordate, deeply in- set; lunular groove wide, vertical. Pseudo-escutcheon well de- fined; hinge plate long and low with a sinuous basal margin; ligamental groove and ligamental pit deep, the latter deeply excavated. Dentition of the right valve of the holotype consists of a small, laminar anterior cardinal (3a); with a triangular, pyramidal anterior cardinal (2), and a thin, curved posterior cardinal (4b). Pedal and adductor muscle scars well incised; pallial line at a moderate distance from the margins. Inner margin with wide crenulations.” (weaveri) “Shell large, outline subquadrate to ovate, the anterior margin passing into the ventral in an evenly rounded arc, the postero- ventral margin attenuate, the posterior slightly curved; umbonal region inflated; beaks low, placed at the anterior one-third. Sculpture (not well preserved in the holotype) consists of 20 to 22 simple, rounded ribs. Ribs almost obsolete in the ventral part of the medial portion of the shell, but distinct to the margin in the anterior and posterior areas. Interradials linear, evanescent in the medial portion and near the ventral area. Incrementals fine, threadlike. Lunule cordate, small; lunular groove wide, trending downward and slightly forward. Pseudoescutcheon present. Hinge plate low and long. Nymph long; ligamental pit in front of the nymph deeply incised; anterior right cardinal (3a), laminar, small; a medial (3b) strong, curved forward, with a long basal margin; a posterior cardinal (5b) thin, cordlike; the left valve with a small trigonal, elongate anterior cardinal (2) and a thin, curved posterior cardinal (4b). Pedal and adductor muscle scars small and shallowly incised. Inner margin crenulate.” (lisa) Holotype.—UW 169; of weaveri CAS/SU 8024; CASG 66530.01; of lisa CAS/SU 8023; CASG 66531.01. Type locality.—UW 169 from the north bank of Cowlitz River, near the bend in sec. 28, T. 11 N., R. 2 W., Little Falls, Lewis County, Wash. Cowlitz Formation, Eocene; of weaveri Southeast bank of Stillwater Creek, 1 V4 miles [2 km] NW of Vader, Wash., Cowlitz Formation, Eocene; of lisa Bluffs along Olequa Creek at Old Ainslee Mill, T. 11 N ., R. 2 W., Lewis County, Wash. Cowlitz Formation, Eocene. Supplementary description.——-“The diagnostic features of V. weaveri are rounded to subquadrate outline, rounded ribs, and the subcuneate shape of the medial cardinal (3b).” (Verastegui, 1953, p. 30) Comparison—“V. weaveri""‘has fewer ribs (by two or three) [than V. gabbi] and‘"the basal margin of its medial cardinal (3b) is narrower. The latter difference may be due to the smaller size of the compared holotype.” (Verastegui, 1953, p. 32) Geographic range—Washington and southern California. Geologic range—Eocene. Occurrence in California—Eocene: “questionably ‘Coldwater”’ (Verastegui, 1953), and Gaviota (Weaver and Kleinpell, 1963) Formations. Venericardia (Pacificor) homii (Gabb) Plate 5, figures 17, 18 Cardita hornii Gabb, 1864, p. 174 (in part), P1. 24, fig. 157. Gabb, 1869, p. 187-188 (in part). E23 Venericardia hornii (Gabb). Hanna, 1925, p. 286-287 (in part), pl. 37, fig. 5; pl. 38, fig. 1; not pl. 39, figs. 1, 2 (=V. (P.) gabbi Verastegui). Venericardia (Venericor) hornii (Gabb). Stewart, 1930, p. 165- 168, pl. 11, fig. 1. Venericardia hornii clarki Weaver and Palmer. Turner, 1938, p. 49 (in part), pl. 14, fig. 1. Venericardia hornii (Gabb) clarki Weaver and Palmer. Weaver in Weaver and Kleinpell, 1963, p. 153, pl. 32, fig. 2; pl. 27, fig. 8. Not Venericardia clarki Weaver and Palmer, 1922. Venericardia (Pacificor) hornii (Gabb). Verastegui, 1953, p. 33-35, pl. 18, figs. 1-7; pl. 19, fig. 7. Givens, 1974, p. 46-47, pl. 3, fig. 3. Venericardia (Pacificor) lisa Verastegui. Weaver and Kleinpell, 1963, p. 200 (in part), pl. 33, fig. 5. Not Venericardia (Pacificor) lisa Verastegui, 1953. Original description .—“Shell large, thick, convex, subquadrate, oblique; beaks prominent, anterior, subterminal; cardinal margin broadly arched, sloping slightly, and uniting with the posterior end with a regular curve; base broadly rounded, most prominent in the middle, from which point it runs upwards rapidly towards the anterior end, which is broadly and regularly curved; poste- rior end obliquely subtruncated, angular below. Surface marked by twenty-two broad rounded ribs, a little the smallest posterior to the umbonal angle; these ribs are somewhat flattened above, especially towards the base, have acute interspaces, and are crossed by numerous coarse, irregular lines of growth. Hinge very thick, robust, and resembling that of C. [ardita] planicosta of the Eocene.” Lectotype.—ANSP 4558 (Stewart, 1930). Type locality.—Live Oak Canyon (LouElla Saul, written com- mun., 1989) near Fort Tejon [Kern County, Calif]. Tejon Forma- tion, Eocene. Supplementary description.—“Typical Venericardia hornii is characterized by an obliquely ovate outline, a pointed to sharply rounded posteroventral margin, and 20-22 rounded radial ribs.” (Givens, 1974, p. 47) Geographic range.—Oregon(?); southern California. Geologic range—Eocene. Occurrence in California.—Eocene: Coldwater Sandstone (Givens, 1974), Gaviota (Clark and Anderson, 1938), and Tejon (Dickerson, 1915; Keen and Bentson, 1944) Formations. Venericardia (Pacificor) aragonia joaquinensis (V okes) Plate 6, figures 1-10; plate 8, figure 3; plate 9, figures 17, 19 Megacardita (Venericor) hornii (Gabb) joaquinensis Vokes, 1939, p. 69—70, pl. 8, figs. 1, 2; pl. 9, figs. 1,2. Venericardia (Leuroactis) joaquinensis (Vokes). Verastegui, 1953, p. 60-61, pl. 11, figs. 1-4; pl. 12, figs. 4-6. Venericardia (Pacificor) aragonia joaquinensis (Vokes). Saul, 1983, p. 76, pl. 2, figs. 7, s. Venericardia ionensis Waring. Hanna, 1925, p. 42, pl. 42, figs. 1, 2. Not Venericardia ionensis Waring, 1914. Venericardia (Leuroactis) schencki Verastegui, 1953, p. 50-51, pl. 4, figs. 6-8. Venericardia (Leuroactis) alisoensis Verastegui, 1953, p. 52-53, pl. 10, figs. 1-3. Megacardita (Venericor) aragonia (Arnold and Hannibal) smileyi Vokes, 1939, p. 67-68, pl. 6, figs. 1-3. Venericardia (Leuroactis) smileyi Vokes. Verastegui, 1953, p. 55- 56, pl. 10, figs. 4, 5. Venericardia (Leuroactis) vokesi Verastegui, 1953, p. 61-62, pl. 14, figs. 1-3. E24 Original description.—“Shell large, heavy, variable in shape; umbos prominent, inflated, anterior; posterior cardinal margin convex, rounded, ventral nearly straight, anterior broadly round- ed ventrally but quite sharply rounded dorsally, straightening out to the small, deeply impressed lunule; sculpture consisting of 21 subobsolete radial ribs appearing as low rounded waves on an otherwise smooth surface; hinge-plate large; posterior cardinal on the left valve long, thin, strongly curved; anterior cardinal short, thin, small; nymph-plate strong, appressed to the poste- rior cardinal at the anterior end.”(ioaquinensis) “Shell large, thick, umbo narrow, convex, elongated diagonally and twisted forward; anterior margin evenly rounded, ventral margin slightly curved, posterior margin truncate; beak prosogyrate, at about the anterior one-third. Ribs 23, broadly rounded in the adult, in the young stage flat-topped, separated by narrow U-shaped interradials gradually becoming linear inci- sions; 16 ribs on the antero-medial portion, 7 compressed cord- like ribs on the posterior area, those nearest the posterior margin less discernible. Incrementals faint, distinctly wavy about 3 cm. from the beak become more sharply defined and threadlike near the ventral margin. Lunule deeply inset, convex, bordered by a deeply incised lunular groove. Escutcheon present. Ligamental groove well defined. Hinge plate very short and high with a straight ventral margin. Anterior cardinal (3a) broken in holotype but apparently placed vertically; socket (2') unusually deep, almost vertical, curving forward; medial cardinal (3b) very prominent, somewhat twisted forward, with a short basal mar- gin and a knife-edged upper end; socket (4b') narrow, deep throughout its length; posterior cardinal (5b) wanting. Interior not well preserved; pedal muscle scar shallow; adductor muscle scars deeply incised; pallial line distant from the margin. Inner margin distinctly crenulate.” (schencki) “Shell large, heavy, with prominent umbos; posterior broadly rounded from umbo to posterior ventral edge where quite angulate, the ventral margin broadly rounded to the anterior cardinal edge, the shell there rounding sharply to the straight anterior cardinal margin; lunule small, deeply impressed; es- cutcheon elongate, well developed; surface with 21 rounded subobsolete ribs separated by narrow linear interspaces, the pos- terior 5 ribs narrower and less well developed than those on the rest of the valve; right valve of the hinge with a large trigonal and curved cardinal; left valve with a small elongate curved pos- terior cardinal, the posterior cardinal broad ventrally.” (smileyi) “Shell large, thick, cordate, obliquely elongate in outline; ante- rior and posterior margins attenuate, ventral very gently curved, and postero-dorsal gently arched. Umbo convex and umbonal ridge even less sharply defined than in V. joaquinensis; beak prominent, prosogyrate, placed at about the anterior one-fourth. Sculpture consisting of 22 broadly rounded ribs; 14 simple ribs well defined in the upper one-third of the shell, becoming incon- spicuous and giving place to fine wavy incrementals, which be- come coarse with age; on the posterior area eight weak ribs, relatively more discernible than the anterior ones and traceable to the ventral margin. Interradials linear in the early part of the shell, becoming obsolete, represented over most of the shell by weakly defined shallow furrows. Lunule deeply inset, the right part three times as large as the left; lunular groove trending downward and backward. Escutcheon well defined by the hinge- cord. Hinge rather low and short, with a straight ventral mar- gin; nymph narrow, long; ligamental pit shallowly incised; dentition strong, consisting in the right valve of a short, small anterior cardinal (3a); a cuneate, elongate medial cardinal (3b) slightly curved forward; and a long posterior cardinal (5b); the figured holotype (left valve) with an anterior cardinal (2) curved upward and forward, elongate and truncate at the upper end, PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA and a curved, long and high posterior cardinal (4b). Other inner characters concealed by matrix.” (uokesi) Holotype.—UCMP 15616; of schencki CAS/SU 8003, CASG 66532.01; of alisoensis UCMP 30176; of vokesi UCMP 15618; of smileyi UCMP 15626. Type locality.—UC 4170. Kings County, Calif. Avenal Sand- stone, Eocene; of schencki: About 2 miles [3 km] northeast of Simi Peak, Simi Hills, Camulos quadrangle, Ventura County, Calif. Santa Susana Shale of Verastegui (1953), Eocene; of alisoensis UC 7019, Los Angeles County, Calif. Llajas Forma- tion, Eocene; of vokesi Two thousand feet [610 m] east and 500 feet [150 m] north of SW corner sec. 17, T. 23 S., R. 17 E., half a mile [1 km] east of Big Tar Canyon, Cholame quadrangle, Reef Ridge sheet, Kings County, Calif. Avenal Sandstone, Eocene; of smileyi UC 672. Fresno County, Calif. Domengine Formation, Eocene. Supplementary description.—‘”l‘he principle [sic] variation in this species is in the height-length ratio. The general features of the outline, notably the shape of the anterior and posterior ends, are constant and appear to be characteristic.” (Vokes, 1939. p. 70) Comparison.—“This subspecies may be distinguished from typical M.[egacardita] hornii (Gabb) and M. hornii clarki (Weaver and Palmer) by the obsolete character of the ribbing. It differs from M. aragonia (Arnold & Hannibal) in being less angulate at the posterior ventral margin, more sharply rounded anteriorly, and in having lower, more massive umbos. It differs from other described forms of Megacardita in both shape and character of ribbing.” (V okes, 1939, p. 70) Comments.—Venericardia (Pacificor) aragonia aragonia (Arnold and Hannibal) does not occur in the Californias; it is restricted to Oregon. Geographic distribution .—Middle and southern California. Geologic distribution.—Paleocene and Eocene. Occurrence in California.—Eocene: Avenal Sandstone (Kappeler and Squires, 1984), Domengine (Vokes, 1939) and Llajas (Squires, 1983; Saul, 1983) Formations, Muir Sandstone (Weaver, 1953), and Santa Susana Shale (Verastegui, 1953). Venericardia (Pacificor) darki popenoei Verastegui Plate 9, figure 7, 15 Venericardia (Leuroactis) popenoei Verastegui, 1953, p. 62-63, pl. 22, figs. 1-3. Venericardia (Pacificor) lisa Verastegui. Weaver and Kleinpell, 1963, p. 200 (in part), pl. 33, figs. 4, 7. Original description.—“Shell large, thick, subquadrate in out- line, with an almost horizontal antero-dorsal margin; the ante- rior margin evenly rounded toward the ventral margin; the antero-dorsal end sharply rounded to subangular. Umbonal con- vexity perceptibly flattening toward the anterior margin. Beak prosogyrate, low, placed at about the anterior one-third. Sculpture"“consists of 21 ribs, simple, flat-topped in the early stage, then rounded until the shell is 35-40 mm. high, and fi- nally become almost obsolete; differentiated as follows: 14 ribs on the antero-medial portion and 7 ribs in the posterior area, not so wide, but slightly more conspicuous. Interradials U- shaped on the tip of the umbo, become linear and gradually dis- appear, their position still marked by the wavy pattern of incrementals. Growth lines or incrementals distinct in the holo- type, fine in the young stage but become coarse with age. Lunule of holotype (left valve) narrow and high; lunular groove well in- cised, trending downward and forward. Escutcheon present and distinctly defined by the escutcheonal cord. Ligamental groove TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE wide and deep. Nymph thin and short; ligamental pit long, in- cised and rough. Hinge plate rather short and low with an al- most straight ventral margin. Dentition (left valve) consists of a bean-shaped anterior left cardinal (2) isolated from the lunular arch, a triangular socket (3b') wide to accommodate a large trigonal cardinal (3b) (a distinctive character of this subspecies), and a thin, high posterior cardinal (4b) slightly broadened ven- trally. Pedal muscle scar small, adductor muscle scars shallowly incised. Pallial line entire, distant from margin, apparently rep- resented by a band of transverse rugosities. Inner margins crenulate.” Holotype.—UCMP 15689. Type locality.—UCLA-581. “East side of main branch of Sespe Gorge, Ventura 00., California.” “Coldwater” Formation, of Verastegui (1953) Eocene. Supplementary description.—The ribs are noded, sharply angled, and probably tripartite, but abrasion and recrystalliza- tion on the holotype have obscured details (LouElla Saul, writ- ten commun., 1989). Comparison.—V. popenoei can be distinguished from V. joaquinensis by the slight concavity in the anterior area of the shell and by the wider trigonal socket. (Verastegui, 1953) “Venericardia (P.) popenoei is proportionately higher than V. (P.) joaquinensis and has fewer ribs” (LouElla Saul, written com- mun., 1989). Geographic range—Southern California. Geologic range.—Eocene. Occurrence in California—Eocene: “Coldwater” (Verastegui, 1953), Sacate (Weaver and Kleinpell, 1963) Formations; Eocene and Oligocene: Gaviota Formation (Weaver and Kleinpell, 1963; Verastegui, 1953). Subgenus VENERICOR Stewart, 1930 Obliquely subtrigonal; immature ribs angular and spaced evenly, in adults flat and low, approximate, and finally vanish- ing; lunule depressed. Geographic range—Europe, North America. Geologic range—Paleocene and Eocene. Comments—Figure 3 shows the phylogeny of Venericor in the eastern Pacific. Venericardia (Venericar) venturensis Waring Plate 8, figures 1, 2, 4, 5, 7, 9, ll, 14 Venericardia planicosta uenturensis Waring in McLaughlin and Waring, 1914, map folio, fig. 12. Waring, 1917, p. 80, pl. 11, figs. 6, 7, 9. Venericardia venturensis Waring. Hanna, 1925, p. 284, pl. 37, figs. 1-4. Stewart, 1930, p. 165. Schenck and Keen, 1950, pl. 19, fig. 5. Venericardia (Venericor) venturensis Waring. Keen and Bentson, 1944, p. 120. Verastegui, 1953, p. 45-47, pl. 3, figs. 1-4; pl. 4, fig. 5. Zinsmeister, 1983, pl. 1, fig. 21. Venericardia (Venericor?) venturensis Waring. Saul, 1983, p. 79, appendix 2, pl. 1, fig. 4 [explanation for plate in error]. Venericardia (Venericor) simiana Verastegui, 1953, p. 47-48, pl. 4, figs. 1-4. Original description—“Shell large, thick, cordate, deeply con- vex, altitude greater than the length; beaks large, turned for- ward, nearly touching; lunule small; anterior cardinal margin deeply excavated in angle; posterior cardinal margin deeply grooved and broadly convex; posterior margin convexly truncate; E25 surface ornamented by 25-30 large, square shouldered ribs, which are strong clear to the margins, with deep squared interspaces; posterior ribs narrow and indistinct; entire surface marked by wrinkled lines of growth. Locality 4, L.S.J.U. Pal. Coll.” (venturensis) “Shell large, thick, cordate in outline, anterior margin broadly rounded, the ventral gently curved, sharply rounded at the postero-ventral end, passing into truncated posterior; umbones slightly convex; posterior area set off both by the umbonal ridge and by the difference in sculpture; beaks low, at about the ante- rior one-fourth. Ribs 28-30; 19 in the antero-medial area persis- tent, V-shaped at beaks flat-topped throughout the surface of the disk and separated by U-shaped interradials. Lunule deeply set, convex, pointing downward and backward, bordered anteriorly by a lunular groove; in the left valve the lunular groove ends in a pustule corresponding to a small depression on the right valve. Escutcheon not defined. Wide ligamental groove and elongated nymph, with a deep triangular ligamental pit at its anterior end. Hinge heavy, low, long, with a distinctly sinuous basal margin; dentition strong and prominent; right anterior cardinal (3a) laminar, vertical, minute; a middle cardinal (3b) curved, scimi- tar-like, with a dorsal edge sharply grooved ventrally; posterior cardinal (5b) thin, almost undifferentiated; paratype No. 8002 with an elongate, cuneate left anterior cardinal (2) and a high, thin, posterior (4b). Pedal scars small; adductor muscle scars concealed by matrix in all specimens examined; pallial line re- mote from the strongly crenulate margin." (simiana) Holotype.—CAS/SU 159; CASG 61667.08; of simiana CAS/SU 8001; CASG 66533.01. Type locality.—SU 2697. Ventura County, Calif. Santa Susana Formation of Zinsmeister (1983), Paleocene; of simiana SU 2697, Ventura County, Calif. Santa Susana Formation, Paleocene. Comparison.—“Venericardia venturensis Waring may easily be distinguished from other Eocene Venericardia of the West Coast by its greater altitude in proportion to its length, and by the squareness of the radial ribs; it may be distinguished from Ve- nericardia ionensis Waring by the radial ribs usually extending to the basal margin. All the individuals referred to this species have been found associated with Martinez fossils.” (Hanna, 1925, p. 284) Geographic range.—Middle California to Baja California Norte. Geologic range—Paleocene. Occurrence in California—Paleocene: Santa Susana Forma- tion (Waring, 1917; Kew, 1924; Verastegui, 1953; Zinsmeister, 1983). Venericardia (Venericor) vallecitosensis (Vokes) Plate 2, figures 3—5, 7 Megacardita (Venericor) vallecitosensis Vokes, 1939, p. 67, pl. 5, figs. 10-12. Venericardia (Pacificor) uallecitosensis (Vokes). Verastegui, 1953, p. 35-36, pl. 12, figs. 1-3. Megacardita (Venericor) hornii (Gabb) carlosensis Vokes, 1939, p. 68-69, pl. 7, figs. 1-6. Venericardia (Venericor) carlosensis (Vokes). Verastegui, 1953, p. 36-37, pl. 13, figs. 4-9. Original description.—“Shell large, heavy, almost circular in outline; umbos moderately inflated; surface with 23 radiating ribs, those on the central portion of the valve being planicostate and separated by flat-bottomed interspaces about two thirds as wide as the ribs; valve slightly angulate at the sixth rib from the posterior margin, the posterior ribs narrow, somewhat ridged E26 and closer together, the anterior 5 or 6 ribs so interrupted by the growth-lines as to appear to be noded, and separated by interspaces wider than the ribs; growth-lines elsewhere on the shell not prominent; lunule small and inconspicuous; hinge-plate small, the central cardinal of the left valve comparatively small, trigonal in shape and somewhat posterior to the umbo; socket large, curved on both the anterior and posterior sides; posterior cardinal long, thin, and high; nymph-plate thin, high, so close to the posterior cardinal as to suggest a deeply grooved tooth.” “Shell moderately large, thin for the genus, variable in shape, quadrate to subtrigonal; umbos small, anterior; lunule minute, deeply impressed; escutcheon narrow, elongate; posterior end of shell obliquely angulate; surface with 21 radial ribs, the poste- rior 5 ribs small, rounded and weakly developed, separated by interspaces of equal width; the 3 ribs anterior to these strongly developed, persistently flat-topped, angulate at the edges, and separated by V-shaped interspaces of equal width; the 5 anterior ribs nodose in appearance due to the strength of the growth- lines and separated by interspaces of equal width; the 8 ribs on the center of the valve minutely nodose in the early stages of development, flat-topped during adolescence, and rounded in the adult; hinge-plate small, the right cardinal curved, narrow and elongate, the nymph-plate long and grooved, the right socket narrow and obliquely set with a small tubercle on the anterior side; the left anterior cardinal small and subtriangular, the pos- terior cardinal long, thin, and curved, the nymph-plate long, low, and so closely set against the posterior cardinal as to appear to be a part of that tooth.” (carlosensis) Holotype.——UCMP 15614; of carlosensis UCMP 15619. Type locality.—-UC A-1022. San Benito County, Calif. Domengine Formation, Eocene; of carlosensis UC A-1017. Top of a small ridge 800' [244 in] SW of Hill 2,200 near center of south edge of sec. 16, T. 17 S., R. 12 E., Priest Valley quadrangle, San Benito County, Calif. Domengine Formation, Eocene. Supplementary description.—“The number of ribs is constant: of 40 specimens examined 4 had 20 ribs, 27 had 21, 8 had 22, and 1 had 23. This form occurs at but one locality***where it is associated with Pelecyora aequilateralis (Gabb), Ostrea idriaensis Gabb, Loxotrema turrita Gabb, Potamides carbonicola Cooper, and Calyptraea diegoana (Conrad). These species suggest that the water was of less than normal salinity, which may be a pos- sible explanation for the thin shell and the great variation in shape.” (Vokes, 1939, p. 69) Comparison.-—“The small umbo and general outline is very sug- gestive of Gabb’s original figure of M .[egacardita] hornii, but the small hinge-plate with the narrow elongate right cardinal, and the character of the ribbing are distinctive.” (V okes, 1939, p. 69) Geographic range—Middle California. Geologic range.—Eocene. Occurrence in California.—Eocene: Domengine Formation (Vokes, 1939; Keen and Bentson, 1944). Subfamily CARDITESINAE Genus GLYPTOACTIS Stewart, 1930 Short trapezoidal, with high nodulose or echinate ribs; small, irregularly convex lunule extending under and slightly behind beaks. Geographic range—North America, Europe, Africa. Geologic range—Cretaceous to Miocene. Comments.—Figure 3 shows the phylogeny of Glyptoactis in the eastern Pacific. PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA Subgenus CLAIBORNICARDIA Stenzel and Krause, 1957 More developed on both sides and with lower beaks than Glyp- toactis (Glyptoactis); ribs triparite, posteriorly echinate; lunule less depressed. Geographic range.—North America, Europe. Geologic range—Paleocene to Eocene. Comments.—Figure 3 shows the phylogeny of Claibornicardia in the eastern Pacific. Glyptoactis (Claibornioardia) sandiegoensis (Hanna) Plate 1, figures 15, 19, 21; plate 7, figs. 15, 22 Cardita sandiegoensis Hanna, 1927, p. 283, pl. 37, figs. 1, 2, 8, 9. Venericardia sandiegoensis (M. Hanna). Stewart, 1946, table 1. Glyptoactis (Claibornicardia) sandiegoensis (Hanna, 1927). Givens and Kennedy, 1979, p. 95, table 1. Squires, 1987, p. 64, fig. 110. Venericardia (Glyptoactis) mcmastersi Verasteg‘ui, 1953, p. 42- 43, pl. 13, figs. 2, 3. Original description.—“Shell of moderate size, elongate-ovate; ventral margin broadly regularly rounded; anterior more sharply rounded; posterior obliquely truncated to slightly rounded; dorsal straight to slightly rounded; beak moderately prominent; surface concentrically striated by distinct growth lines; radially striated by fifteen to nineteen prominent ribs; posterior ribs rather sharp, separated by sharply rounded interspaces; the posterior ribs are only slightly terraced on ei- ther side; terracing becomes more prominent on the anterior half of the shell, so much so that the anteriormost ribs are nearly three separate ribs, each group of three ribs wider and separated by narrower shallow interspaces; from the beak to the posterior ventral point the shell is ventricose, less ventricose both to the anterior and to the posterior of this line; inner mar- gin deeply crenulate; hinge plate narrow, typically carditiform. Dimensions. Cotype 30983: Altitude 33 mm., length 45 mm.” (sandiegoensis) “Shell small, quadrate in outline, anterior margin evenly rounded, the ventral slightly curved, the posterior distinctly truncated, making an angle of 90° with the ventral margin; postero-ventral and postero-dorsal ends sharply rounded to sub- ang'ular, accentuating the quadrate outline of the shell. Umbo strongly inflated, curved forward, prosogyrate, with beak placed at about the anterior one-fourth. Umbonal ridge, delimiting the posterior area, defined by the change in the coarseness of the ribs. Sculpture similar to that of V. keenae, n. sp., consisting of 21 well-developed ribs; 4 simple crowded ribs on the anterior portion followed on the medial portion by 9 ribs definitely ter- raced on both sides; 8 ribs on the posterior area simple, V- shaped; the crest of the ribs bears fine nodes which are conspicuous on the ventral area of the valve. Interradials U- shaped. Incremental sculpture fine. Lunule small, semicordate, trending forward and downward, with deeply incised lunular groove. Escutcheon narrow. Hinge plate low and long, with an arched ventral margin. Nymph thin; ligamental pit inconspicu- ous. Dentition consisting of pustule-like anterior left cardinal (2), broken off in the holotype; and a slender, long posterior car- dinal (4b). Pallial line entire, closely placed to the margin. In- ner margin strongly crenulate.” (mcmastersi) Types.—Syntypes UCMP 30980-30983; holotype of mcmastersi CAS/SU 8011; CASG 66534.01. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE Type locality—U0 5062. San Diego County, Calif. Rose Can- yon Shale of Hanna (1927), Eocene; of mcmastersi San Clemente Canyon, San Diego Co., California. La Jolla Group, Eocene. Camments.——Stewart (1930, p. 152) suggested that sandiegoensis might be a Glyptoactis. Geographic range—Middle and southern California. Geologic range—Eocene. Occurrence in California.—Eocene: Avenal Sandstone (Stewart, 1946), Delmar Sand and Rose Canyon Shale (Hanna, 1927), and Juncal Formation (Squires, 1987). Glyptoactis (Claibornicardia) keenae (Verastegui) Plate 8, figures 6, 8, 10, 12, 13, 15 Venericardia (Glyptoactis) keenae Verastegui, 1953, p. 41-42, pl. 1, figs. 1-5. Smith, 1975, p. 470, pl. 2, fig. 5. Venericardia (Pacificor) argentea Verastegui, 1953, p. 25-26, pl. 1, figs. 10-14. Original description.—“Shell small, cordate-subquadrate in outline, anterior and ventral margins broadly rounded, the pos- terior truncated and the dorsal margin slightly arcuate; umbo strongly convex with the most prominent point above and slightly anterior to the mid-point of the disk; posterior area sharply delineated by a change in sculpture and radially de- pressed; beak prosogyrate, low and compact. Sculpture distinct, consisting of 30 ribs persistent throughout the entire surface of the shell; of these, the 4 anterior ribs crowded, thin, faintly fas- ciculate, (slightly terraced); the next 14 ribs conspicuously ter- raced, so that they appear to be tripartite with a central crest bordered on each side by smaller riblets (the central crest beaded with light funnel-shaped tubercules not discernible upon ribs of the umbonal area); the succeeding 4 ribs with a terraced face only on the posterior side; posterior area with 4 crowded V- shaped ribs; the remaining 4 ribs a little wider, with riblets on the posterior side. Interspaces at the anterior and posterior por- tions V-shaped; in the medial area, with deep U-shaped chan- nels. Incrementals fine and sharp, more noticeable on the posterior area of the adult shell. Lunule small, distinctly convex, bounded by an incised lateral groove which in the left valve ends ventrally, with the walls of the trough forming a knob (the ante- rior pustule of Stewart). Escutcheon slightly discernible, bor- dered below by a cord. Ligamental groove narrowly incised. Nymph narrow and elongate. Ligamental pit not evident. Hinge plate low and short with a straight ventral border; dentition of the left valve consists of a nearly trigono-pyramidal anterior car- dinal (2), isolated from the lunular plate; and a thin posterior cardinal (4b) broadens toward the ventral end. Pedal muscle scar small and shallowly incised; adductor muscle scars moder- ately incised, pallial line entire and remote from the ventral margin. Inner margins crenulate.” “Shell of medium size, inflated-ovate in outline with the ven- tral margin broadly rounded, umbones prominent, greatest infla- tion a little above the center of the disk the surface rounds off broadly in all directions, except toward the posterior slightly concave dorsal slope; beak prosogyrate, low and compact, placed at about the anterior one-third. Ribs 30 to 32; typical Pacificor sculpture (as described in the diagnosis of the subgenus). Poste- rior area with 10 ribs; the 5th nearest the dorsal margin wide, with one posterior riblet; the other 5 thin, crowded, V-shaped, with corresponding V-shaped interspaces. Interspaces in the me- dial portion squarely channeled, one-third the width of the ribs. Frontal rib crests show a beadlike appearance as in V. mulleri. Lunule small, convex, sloping forward, (not well preserved in the E27 holotype). Pseudoescutcheon present. Ligamental groove deeply incised; nymph long and wide; ligamental pit shallowly incised. Hinge plate low and short; dentition of the left valve with a strongly developed, scimitar-like anterior cardinal (2), projected over the medial plane, and a thin posterior cardinal (4b) which thickens gradually toward the ventral end. Pedal muscle scars normally incised. Adductor muscle scars and pallial line con- cealed by matrix.” (argentea) Holotype.—CAS/SU 7992; CASG 66535.01; of argentea CAS/SU 7995; CASG 66535.02. Type locality.—SU 2073. Fresno County, Calif. Base of Lodo Formation, Paleocene; for argentea the same. Geographic range—Middle California. Geologic range—Paleocene. Occurrence in California.—Paleocene: Basal part of the Lodo Formation (V erastegui, 1953; Smith, 1975). Glyptoactis (Claibornicardia) marksi (Verastegui) Plate 7, figures 17, 19 Venericardia (Glyptoactis) marksi Verastegui, 1953, p. 44, pl. 19, figs. 2-4. Original description.—“Shell small, thin, outline subcircular, the anterior and ventral margins evenly rounded, the postero- ventral truncated, the postero-dorsal slightly arched. Umbo fairly convex, prominent, with the greater inflation in the middle of the disk; beak prosogyrate, heavy, full, placed at about the anterior two-fifths. Sculpture consists of 18 ribs strongly orna- mented by fine closely spaced beads along the crests; of these, the 5 in the anterior area thin, simple, separated by wide U- shaped interspaces twice as wide as the ribs; the 8 medial ribs simple in the early umbonal area, but become terraced (tripar- tite) in the mature part of the shell; interspaces wide, U-shaped; the 5 ribs on the posterior area closely spaced and thin with interspaces V-shaped; incrementals fine, more visible on the flat- bottomed interspaces. Lunule small, convex. Escutcheon want- ing. Hinge rather high for the subgenus; dentition of the right valve consists of a small anterior cardinal (3a), a cuneate long medial cardinal (3b), and a slender posterior cardinal (5b). Inte- rior of the holotype concealed by matrix except for the inner margin, which is strongly crenulate.” Holotype.—CAS/SU 8021; CASG 66536.01. Type localilty.—SU 183. "East side of Live Oak Canyon, Kern Co., California.” Live Oak Member of the Tejon Formation of Verastegui (1953), Eocene. Comparison.—““"V. marksi can be readily distinguished from V. domenginica by its heavier and less pointed beak, by its circular outline, and by the greater convexity of the shell.” (Verastegui, 1953) Geographic range—Southern California. Geologic range—Eocene. Occurrence in California.—Eocene: Cozy Dell Formation (Weaver and Kleinpell, 1963) and Live Oak Member, Tejon For- mation of Verastegui, 1953. Glyptoactis (Claibornicardia) domenginica (Vokes) Plate 7, figures 10, l2, 13, 16, 18, 20 Venericardia (Glyptoactis?) domenginica Vokes, 1939, p. 66, pl. 5, figs. 7-9. Venericardia (Glyptoactis) domenginica Vokes. Verastegui, 1953, p. 43, pl. 13, fig. 1. Glyptoactis domenginica (V okes). Givens, 1974, p. 47. E28 Glyptoactis (Glyptoactis) domenginica (Vokes, 1939). Squires, 1984, p. 46—47, figs. 10q-r. Squires, 1987, p. 63-64, fig. 109. Glyptoactis (Claibornicardia) domenginica (Vokes, 1939). Squires, 1988, p. 19, fig. 50. Original description.—“Shell small, moderately inflated, in- equilateral, almost circular in outline; umbo small, high, promi- nent; lunule impressed; sculpture consisting of 17 radial, ridged, strongly beaded ribs, separated by round-bottomed interspaces slightly more than half as wide as the ribs, the ribs being finer and closer together on the posterior portion of the valve; poste- rior cardinal of the hinge in the right valve long, slender, curved, the anterior cardinal in the left valve reduced to a small rugosity bounding the anterior end of the large central socket, with a well-defined anterior lateral pustule.” Holotype.—UCMP 15611. Type locality.—UC A-1219. Fresno County, Calif. Domengine Formation, Eocene. Supplementary description .—“This species is more typical of the subgenus Claibornicardia Stenzel and Kraus (in Stenzel et al., 1957) than of the subgenus Glyptoactis Stewart (1930). Heaslip (1968:98, 110) compared these two subgenera and reported that only Claibornicardia had spinose ribs, and that it lacked the diag- nostic ‘tooth’ that Glyptoactis had above the intersection of the lunule and the anterior point of the left posterior cardinal tooth. Glyptoactis (Claibomicardia) domenginica has spinose radial ribs and lacks the diagnostic tooth’.” (Squires, 1988, p. 19.) “""""‘the specimens show the diagnostic 16 to 17 noded tripar- tite ribs that are finer and closer together on the posterior por- tion of the valve. The tripartite nature of the ribs also becomes less apparent posteriorly. ”(Squires, 1988, p. 19) Comparison.—“V. domenginica differs from all the described western Eocene species referred to the Carditidae in size, shape, and character of the ribbing. It finds its nearest analogue in the group of V. acuticostata in the Lutetian-Bartonian of France.” (Vokes, 1939, p. 66) Geographic range—Middle and southern California. Geologic range—Eocene. Occurrence in California—Eocene: Domengine, Llajas, and Tejon Formations (Vokes, 1939); Junca1(?) Formation (Squires, 1988). Subfamily THECALIINAE Genus MILNERIA Dall, 1871 Narrowly trapeziform, very inequilateral, with two median posterior angulations, finely echinate ribs, concentric lines; beaks orthogyrous. Geographic range—Middle California to Baja California Sur. Geologic range.—Pliocene to Holocene. Habitat.—Intertidally to 27 m, byssate and nestles on flat surfaces like the backs of Haliotis (Hertlein and Grant, 1972, p. 240); intertidally to 80 m (Bernard, 1983). Milneria minima (Dall) Plate 9, figures 16, 18 Ceropsis minima Dall, 1871, p. 152, pl. 16, figs. 5, 6. Milneria minima Dall. Hertlein and Grant, 1972, p. 234, pl. 43, figs. 1, 2, 14. Coan, 1977, p. 384. Original description.—“Shell minute, trapeziform, white, with a thin brownish epidermis. Umbones prominent, nearly termi- nal. Anterior margin rather strongly angulated; basal margin straight, or a little concave; lower posterior extremity angulated; PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA upper posterior angle rounded off; posterior margin rather ob- lique. Hinge line smooth, rather broad. Ligament conspicuous, moderately long. A rounded carina passes from the umbo to the lower posterior angle, above which are from two to five radiating ribs. General sculpture of sharp elevated lines of growth, which become vaulted scales on the ribs. Margin lightly crenulated. In- terior polished; muscular and pallial impressions indistinct. Long. 14, lat. 08., alt. .175 in.” Lectotype.—USNM 63349 (Coan, 1974). Type locality,——“Habitat, nestling or burrowing in Haliotis rufescens, at Monterey, also dead on beach.” Comparison—“The major radial ribs on M. minima are rather coarse and are about equal in size, whereas those on M. kelseyi are finer and less coarsely scaled. The umbonal and one or more of the other ribs are higher than the rest. Furthermore the lunule of M. kelseyi is smaller and the escutcheon larger than that of M. minima. Milneria kelseyi attains a greater size than M. minima, up to 8 mm long‘“.” (Hertlein and Grant, 1972, p. 234) Geographic range.—Living: Monterey, Calif, to lsla de Nativ- idad, Baja California Sur. Geologic range—Pliocene to Holocene. Occurrence in the Californias.—Pliocene: San Diego Formation (Hertlein and Grant, 1972); Pleistocene: unnamed strata in the Palos Verdes Hills, San Pedro, Calif. (Woodring and others, 1946), and on San Nicolas Island (Vedder and Norris, 1963). Habitat.—Intertidally to 80 m in the eastern Pacific (Bernard, 1983). Attaches to hard substrates by a byssus (Coan, 1977). FOSSIL LOCALITIES [Corrections and information not in the original description are in brackets: feet and miles are converted to the metric system, formations are cited as amended by later workers, where pertinent] California Academy of Sciences: CA5 65. West bank of a small canyon 2 km NE of Barker’s Ranch House [SE ‘/4, sec. 32, T. 28 S., R. 29 E., Caliente quadrangle], Kern County, Calif. Temblor Formation. CAS 244. In east bank of Live Oak Creek, 1.2 km from mouth, 4.8 km due east of mouth of Grapevine Canyon, Tejon quadrangle, Kern County, Calif. Tejon Formation. Los Angeles Natural History Museum: LAM 305. 730 m east and 310 in south of NW cor. sec. 8, T. 19 S., R. 2 W., S.B.M., San Ysidro quadrangle, 1943 ed. [San Diego County], Calif. San Diego Formation. LAM 305c. Hills south of Tijuana River at Palm City, Calif. “K” Ranch, exactly 290 ft [88m] from the U.S.-Mexican border fence. Southwest of Goat Canyon, at base of bill 100 ft [31 in] W., 440 ft [134 m] S. of NE cor. sec. 8. Imperial Beach quadrangle, San Diego County, Calif. San Diego Formation. Stanford University [These collections are now all in the California Academy of Sciences]: SU 2073. Road cut just south of middle of section line between secs. 20 and 29, in sec. 29, T. 15 S., R. 12 E., opposite junction of Panoche and Silver Creeks, Panache quadrangle, Fresno County, Calif. Basal part of Lodo Formation. SU 2696. McCray wells [Oil Canyon, 3 miles [5km] north 20° east of BM. 961 at Santa Susana, Santa Susana quadrangle, Ventura County, Calif]. LlaJ'as Formation. SU 2697. Simi Hills, [4.5 km ENE of Simi Peak, near head of east fork of Las Virgenes Canyon], Camulos quadrangle, Ventura County, Calif. Santa Susana Formation. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE University of California at Berkeley: UC 672. South part of crest of Parson’s Peak, SEl/A, N‘A, sec. 24, T. 18 S., R. 14 E., Coalinga quadrangle, Fresno County, Calif. Domengine Formation. UC 2033. South of Hill 651 about 400 m, 800 in west of Kirkers Creek, near west edge sec. 30, T. 2 N., R. 1 E., Mt. Diablo quadrangle, Contra Costa County, Calif. Kirker Tuff, Oligocene. UC 3765. NW1/4SW‘/, sec. 24, T. 2 N., R. 18 W., 2,060 m E of Hill 2150, Simi Hills, Camulos quadrangle, Ventura County, Calif., Martinez Group of Dickerson (1914); Santa Susana Formation of Zinsmeister (1983). UC 3990. On the east side of canyon in bottom of Rose Creek, 485 in east of “t” of “Soledad Mountain,” La Jolla quadrangle, San Diego County, Calif. UC 4170. West side of Big Tar Canyon, T. 23 S., R. 17 E., Cholame quadrangle, Kings County, Calif. Avenal Sand- stone. UC 5062. In sea cliff south of mouth of Soledad Valley, due west of midpoint between “P" and “u” of “Pueblo,” La Jolla quadrangle, San Diego County, Calif. UC 7004. Branch of Las Llajas Canyon just north of north- ernmost extent of 1,500-foot contour, Simi Valley (Santa Susana quadrangle), Ventura County, Calif. Llajas Forma- tion. UC 7019. West side of Aliso Canyon West, beds striking northwest and dipping west. Fossils occur in narrow lenses. Elev. 555 in. Los Angeles County, Calif. UC A-1219. West side, near top of long ridge extending northwest of Hill 2126, on line between secs. 9 and 16, T. 19 S., R. 15 E., Coalinga quadrangle, Fresno County, Calif. Domengine Formation. UC A-1022. 300 ft. [90 m] above mouth and 20 ft. [6 m] up north wall of small canyon entering San Carlos Creek, south edge of sec. 16, T. 17 S., R. 12 E., Priest Valley quadrangle [San Benito County, Calif]. Domengine For- mation, Eocene. UC A-1233. West of Roseburg, Douglas County, Oreg. Umpqua Formation. UC A-3582. Bahia Santa Inez, from 6-m terrace level ex- tending from locality UC A-3581 to beach. Baja California Sur. UC A-3670. Puerto Balandra, Isla Carmen, from sands at left end of outcrop and below base of coral reef, Baja Cali- fornia Sur. GEOLOGIC FORMATIONS CITED FOR OCCURRENCE OF PELECYPODS Family Erycz'nidae through Carditidae Name Age California: Avenal Sandstone --------------- Eocene. Capistrano ------------------------- Miocene and Pliocene. Cebada Member, Careaga Sandstone ----------------------- Pliocene. Cerros Shale Member, Lodo Formation ----------------------- Paleocene. Coal Canyon Formation ------ Paleocene. E29 Coldwater Sandstone or “Goldwater” Formation ----- Eocene. Cozy Dell Formation or Shale -------------------------- Eocene. Delmar Sand ---------------------- Eocene. Dip Creek Formation ---------- Late Cretaceous and Paleocene. Domengine Formation or Sandstone ----------------------- Eocene. Elk River Formation ----------- Pleistocene. Fernando Formation ----- --- Pliocene and Pleistocene. Foxen Mudstone ----------- --- Pliocene. Gaviota Formation ------------- Eocene and Oligocene. Graciosa Member, Careaga Sandstone ----------------------- Pliocene. Juncal Formation --------- --- Eocene. Kirker Tuff ------------------------ Oligocene. La Jolla Formation or Group ----------------------------- Eocene. Live Oak Member, Tejon Formation ------ --- Eocene. Llajas Formation - ----Eocene. Lodo Formation ------------------ Paleocene and Eocene. Lomita Marl Member, San Pedro Formation -------- Pleistocene. Martinez Formation or Group ------------------------- Paleocene. Meganos Formation ------ ---Paleocene and Eocene. Monterey Shale ------------------ Miocene. Muir Sandstone ------------------ Eocene. Pancho Rico Formation - ---Miocene. Pico Formation ------------------- Pliocene and Pleistocene. Rio Dell Formation ------------- Pliocene and Pleistocene. Rose Canyon Shale ------- --- Eocene. Round Mountain Silt ---------- Miocene. Sacate Formation --------------- Eocene. San Diego Formation ---------- Pliocene. San Francisquito Formation ----------------------- Paleocene. San Pedro Formation or Sand --------------------------- Pleistocene. Santa Barbara Formation --- Pliocene and Pleistocene. Santa Susana Shale or Formation ----------------------- Paleocene and Eocene. Saugus Formation -------- --- Pliocene and Pleistocene. Sisquoc Formation ----- ---Miocene and Pliocene. Tejon Formation ----------------- Eocene. Timms Point Silt Member, San Pedro Formation -------------- Pleistocene. Towsley Formation ------------- Miocene and Pliocene. Baja California peninsula: Bateque Formation ------------- Paleocene(?), Eocene Comondu Formation ----------- Pliocene. Marquer Formation ------------ Pliocene. Oregon: Cowlitz Formation -------------- Eocene. Umpqua Formation or Group ------------------------- Eocene. Washington: Cowlitz Formation -------------- Eocene. Stratigraphic nomenclature used is that of the references cited in the text and does not necessarily accord with that of the US. Geological Survey. E30 REFERENCES Abbott, R.T., 1974, American Seashells [2d ed.]: New York, Van N ostrand Reinhold, 663 p., 24 pls. 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Weaver, D.W., and Kleinpell, R.M., 1963, Mollusca from the Turritella variata Zone, in Kleinpell, R.M., and Weaver, D.W., Oligocene biostratigraphy of the Santa Barbara Em- bayment, California: University of California Publications in Geological Sciences, v. 43, pt. 2, 250 p., 38 pls. Willett, George, 1946, Additional notes on the Pliocene mollus- can fauna of Los Angeles city (California): Southern Califor- nia Academy of Sciences Bulletin, v. 45, pt. 1, p. 28—32. Woodring, W.P., and Bramlette, M.N., 1950, Geoloy and paleon- tology of the Santa Maria district, California: U.S. Geologi- cal Survey Professional Paper 222, 185 p., 23 pls., 9 figs. Woodring, W.P., Bramlette, M.N., and Kew, W.S.W., 1946, Geolo- gy and paleontology of the Palos Verdes Hills, California: U.S. Geological Survey Professional Paper 207, 145 p., 37 pls. Yonge, C.M., 1951, Studies on Pacific Coast mollusks, VI. A note on Kellia laperousii (Deshayes): University of Califor- nia Publications in Zoology, v. 55, no. 11, p. 451—453, fig. 1. TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E33 1969, Functional morphology and evolution within the Carditacea (Bivalvia): Malacological Society of London Pro- ceedings v. 38, no. 6, p. 493—527, 25 figs. Yonge, C.M., and Thompson, T.E., 1976, Living marine mollusks: William Collins Sons, London, 288 p., 16 pls., 162 figs. Zinsmeister, W.J., 1970, A late Pliocene macrofossil fauna of Newport Beach, Orange County, California: Southern California Academy of Sciences Bulletin, v. 69, p. 121—125. 1983, Late Paleocene (“Martinez provincial Stage”) mollus- can fauna from the Simi Hills, Ventura County, California, in Squires, R.L., and Filewicz, M.V., eds., Cenozoic geology of the Simi Valley area, southern California: Society of Eco- nomic Paleontologists and Mineralogists, Pacific Section, Los Angeles, Calif, p. 61—70, 4 pls. A Abbott, R.T., cited, 4, 10 quoted, 9 Abstract, 1 Acknowledgments, 4 acuticostam, Venen'cardia, 28 Addicott, W.O., cited, 14 aequara, Aligena nuca, aequilareralis, Pelecyora, 26 affinis, Byssomera (Byssomem), 5 Cardim, 11 (Bysxomera), 11; pl. 9 Cardilamera (Byssomera), ll Glam, 15 alaskana, Venerr'cardr'a (Cyclocardia), 14 Aligena, 5, 7 aequata ma, 8 (Aligena) diegoarra, 5, 7; pl. 1 cem'tensis, 8 diegoana, 7, 8 laevr's, 8 (Aligena), Aligena diegoana, 5, 7; pl. 1 alrlroemis, Venerr'cardia (Leuroactr's), 23; pl. 6 Anderson, F.M., quoted, 6 aragom'a, Megacardr'ta, 24 Venerr'cardia, 19 (Pacificor), 27; pl. 8 aragonia, 18, 24 diabloensis, 17, 18, 20; pl. 5 joaquinensis, 17, 18, 23; pls. 6, 8, 9 (Venericor) smileyi, 23 Avenal Sandstone, 24, 27 B Bahia San Quintin, 6 barbarensr's, C ardita, 15 Cyclocardr'a, 15 (Cyclocardia), 12, 15 ; pl. 5 Venerr'cardr'a, 13, 1 Basterotella, 10 (Basterotella), Basterotia hertler'ni, 5, 10; pl. 9 Basteron'a, 5, 10 (Basterotella) hertleim', 5, 10, pl. 9 calrfornr'ca, 10 ecuadorr'ana, 10 hertleiru', 10 peninsulare, 11 Bateque Formation, 20, 21 Bentson, Herdis, cited, 1 Bernard, F.R., cited, 4, 6, 7,9,10,11,12, 14,15,16, 28 borealr's, Cardita crebricostata, 14 Venericardia, 1 3 Bornia, 5, 8 (T emblornr'a) frankiana, 5, 8; pl. 3 triangulata, 5, 8; pl. 3 Bramlette, M.N., cited, 13 quoted, 15 Byssamera, 11 (Byssomera) afi‘inr’s, II ; pl. 9 Carditamera afi‘inr's, 11 calafia, Venericardia hornir', 21, 22 (Pacr'fr'cor), 21 01114111, 17, 18, 21; 1. 3 gabbi, 17, 18, 22; l, 4 lutmanr',17,18, 2;; p15. 2,4, 5 .rusanaensr's, 17, 18, 19; pl. 1 calrfomica, Basterotia, 10 Cardila, 13 INDEX [Italic page numbers indicate major references to accepted taxa] C yclocardr'a, 13 Cyclocardia), 12, 13; pl. 7 Venen'cardia (Cyclocardia), 13 Calypmzea diegoana, 26 Capistrano Formation, 6, 15 Cardita. 4, 5, 11 afiinis, 11 barbarensis, 15 borealr's crebricostata, 14 (Byssamera) affinis. 5, 11; pl. 9 californr'ca, l3 (Cardita) superioris, 5, 11; pl. 4 horm'i, 23 megastrapha , l2 mom'lr'costa, l3 occidentalr's, l3 planicosta, 22 sandr'egoensis, 26 (S traphocardia) megastropha, 12; pl. 7 superioris, 11 venertfomris, 16 venm'cosa, 14 “Cardita”venen_'fonnis, 16 (Cardita), Cardin: superioris, 5, 11; pl. 4 Carditamem (Byssomera) affinis, 11 Carditesinae, 26 Carditidae, l, 11, 28 C ardium kikerensis, 12 Careaga Sandstone, 7, 9, 13, 15, 16 carlosemr's, Megacardr'ta (Venericar) horm'r', 25 Venen'cardia (Pacificor) harru'i, 32 Venen'cor (Venerr'cor), 25 Carpenter, P.P., noted, 15 catacta, Kellia, , 6, 7, 31 Cebada Member, 7, 13, 15, 16 Centrocardr'ta. 15 (Centrocardr'ta), Glam- veneriformis, 12, 16; pl. 7 Cerapsis minima, 28 cerrr'tensis, Aligena, 8 Cerros Shale Member, 6 chiroru', Kellr'a laperousii, 7 Chironia laperousii, 7 suborbicularis laperousr'r', 7 cr'smla, Msaea, 6 Claibarm'cardia, 18, 28 (Claibornicardia) Glyptoactis damenginica, 17, 18, 27, 28; pl. 7 keenae, 17, 18, 27; pl. 8 marksi,17, 18, 27, pl. 7 mcmastersi, 1. 7 sandiegaensrs, 17, 18, 26; ls. 1, 7 clarki, Megacardr'ta harm'i, Venerr'cardia, 22, 23 hornii, 22, 23 (Pacificor) clarki, 17, 18,22; 1.5 popenoei, 17, 18, 4; p1. 9 Coal Canyon Formation, 19 Conn, E.V., cited, 10, 14, 15, 16, 28 quoted, 15 Coldwater Formation, 23, 25 Sandstone, 23 Comondr'r Formation, 10, 11, 13 comprarsa, Erycina (Pseudopythina), 10 Neaeromya (Orbitella), 5, 10; pl. 4 “Orbitella” 10 Pseudopythina, 10 conspicua, S renoplax, 9 Corbula (Cuneocorbula) .rwr'ftiana harrisr', 6 ham'sr', 6, 7 uvasana, 6 Cowlitz Formation, 23 Cozy Dell Formation, 27 crebricosmra, Cardira borealis, 14 Cyclocardr'a, 14 (Cyclocardia), 12, 14; 1. 7, 9 crescentensis, Venen'cardia ( acrficor), 18 (C uneocorbula), Carbula swiftr'ana harrr'sr', 6 Cyclocardia 4, 12 barbarensis, 15 californr'ca, 13 crebrr'castam, 14 (Cyclocardia) barbarensr's, 12, 15; pl. 5 californica, 12, 13; pl. 7 crebn'cosmm, 12, 14; pl. 7, 9 kirkerensis, 12; 1. 9 momereyana, 12,, 13; pl. 7 occidentalis, 12, 13; pl. 9 vemicosa, 12, 14; pl. 9 accidentalis, 13 venm’casa, 14 (Cyclocardia) C yclocardia barbarensis, 12, 15; pl, 5 caltfarnica, 12, 13; pl. 7 crebricosmm, 12, 14', pl. 7, 9 kirkerensis, 12 ; pl. 9 montereyana, 12, 13; pl. 7 occidentalis, 12, 13; pl. 9 ventricosa, 12, 14; pl. 9 Venericardia alaskana, 14; 1. 9 californica, 133 D Delmar Sand, 27 diabloensr's, Venerr'cardia (Pacificor), 20, 32 aragom'a, 17, 18, 20; pl. 5 diegoana, Aligena, 7, 8 (Aligena), 5, 7; pl. 1 Calytraea, 26 Dip Creek Formation, l7 Domengine Formation, 24, 26, 28 domenginica Glyptoactis, 27 (Claibornicardia), 17, 18, 27, 28; pl. 7 Glyproactis), 28 Venericardia, 27, 28 (Glyptoactr's), 27 (Glyptoacti57), 27 Donax triangulata, 8 Durham, I.W., cited, 4,11,12 quoted, 11 durhami, Venericardr'a (Pacifism), 20; pl. 2 E ecuardorr'ana, Busterotr'a, 10 Elk River Formation, 15 Emerson, W.K., cited, 11, 12 Erycina (Pseudopythina) compressa, 10 Erycinidae, 1, 5 F Fernando Formation, 13, 14, 15, 16 Fossil localities, 28 Foxen Mudstone, 13, 16 frankiana, Bornia (Temblorm'a), 5,8; pl. 3 G gabbr', Venerr'cardia, 22, 23 (Pacificor), 22 calafia, 17, 18, 22; pl. 4 Gale, H.R., quoted, 15 Gaviota Formation, 23, 25 Geologic Formations, lee ds in, 29 Glans, 12, I5 Pe ypo afi‘inis, 11 (Centrocardita) venenformr's, 12, 16; pl. 7 (Glam) subquadrata, 12, 15; pl. 5 minuscula, 15 subquadrala, 15 (Glans), Glam subquadrata, 12, 15; l. 5 Glyploacris, 4, 17, 18, 2 ,28 (C laibornr'cardr'a) domengim'ca, 17, 18, 27, 28; pl. 7 keenae, 17, 18, 27; pl. 8 marksi, 17,18, 27; pl. 7 mcmastersr'; 1. 7 sandiegoensrs, 17, 18, 26; pl. 1, 7 domengr'nica, 27 E35 E36 PALEONTOLOGY OF CALIFORNIA AND BAJ A CALIFORIA (Glyptaactis) damengiru'ca, 28 phylogeny sandiegoensis, 27 (Venerr'cor) valleciwsem‘is, 18 venturensis, 18 (Glyptaacn's) Glyptoactis domenginica, 28 Venericardia domenginica, 27 keznae, 27 marksi, 27 mcmastersi, 26 (Glyptoactis?), Venen'cardia domenginica, 27 Gordon, Mackenzie, J r., cited, 4, 6 Gould, A.A., quoted, 14 Graciosa Member, 9, 13, 16 Grant, U.S., IV, cited, 4, 6, 7, 10, 14,16, 28 quoted, 8, 9, 15 Graysian Stage, 14 Haliotis nfescem‘, 28 Hanna, GD., quoted, 6 harrisi, Corbula, 6, 7 (Cuneocorbula) swiftiana, 6 Hertlein, L..,G cited, 4, 6, 7, 10, 11, 12, 14, 16, 28 quoted, 8, 9, l6 henleini, Basterotia, 10 Basteratia (Basteratella), 5, 10; 1.9 Venericardia (Pacificor) 21; pl § hornii, Cardim, 23 Megacardr'ta, 24 clarki, 24 (Venericor) cariosensis, 25 joaquineru'is, 23 Venencardia calafia, 21 , 22 clarh', 22, 23 lutmani, 20, 21 planicosta, 22 (Pacificor) 17, 18, 20, 22, 23; pl. 5 carlosensis; pl. 2 lutmani, 20 manaensis, 19 (Venericor), 23 Introduction, 1 ionensis, Venen‘cardia, 23, 25 Isla San Martin, 6 J joaquinensis, Megacardita (Venericor) hon-ii, 23 Venerr'cardia, 24, 25 (Leuroacn's), 23 (Pacificar) aragonia, 17, 18, 23; pls. 6, 8, 9 Jones, G.F., cited, 14, 15 Juncal Formation, 21, 27 K Keen, A.M., cited, 1, 4, 6,10,11,12 quoted, 8, 10 keenae, Glypwacn's (C larbornicardm), 17, 18,27; P1- Venericardr'a (Glyptoactis), 27 Kellia, 5, 6 catacta, 5, 6, 7; 1. l Iajollaens‘r's, 5, , 7; pl. 3 laperousii, 5, 7; pl. 3 rotunda, 7 suborbicularis, 7 uvasana, 5, 6, 7; pl. 3 Kelliidae, l, 6 kelseyi, Milneria, 28 Kirker Tuff, 13 kirkeremis, Cardium, 12 C yciocardia (C yclocardia), 12; pl. 9 L La Jolla Group, 27 laevis, Aligena, 8 lajollaensis,Kellia, 5, 6. 7; pl. 3 laperousii, C hironia, 7 suborbiculan's, 7 Kellia, 5, 7; pl. 3 chironi, 7 Lasaea, 5 cistula, 6 purpurata, 6 rubra subviridis, 6 scalar-fa, 6 subviridis, 5, 6; pl. 1 Lazaria subquadrala, 15 (Leuraactis), Venericardia alisoensis, 23, 36 joaquinensis, 23 popenoei, 24 schenckz', 23, 36 smileyi, 23 vokesi, 23 Iisa, Venericardia (Pacificor), 22, 23, 24 Live Oak Member, 27 Llajas Formation, 11, 21, 22, 24, 28 Lodo Formation, 6, I9, 27 Lomita Marl Member, 15, 16 Lookingglass Formation, 21 Loxotrema write, 26 lutmani, Venericardia 20, 22 hornii, 20, 21 (Pacificor), 20 calafia, 17,18, 20; pls. 2, 4, 5 hornii, 20 M marlm',Glyploactis(CIaibornicardia),17, 18,27; .7 Venericardia, 27L (Glyptoactis), 27 Marquer Formation, ll, 12, 13 Martinez Formation, 19 mcmastersi, Glyptoactis (Claibornicardia); pl. 7 Venen'cardia (Glyptoactis), 26 Megacardita, 24 aragonia, 24 hornii, 24 clarki, 24 (Venericor) aragonia smileyi, 23 hornii carIosensis, 25 joaquinensis, 23 vallecitosensis, 25 Meganos Formation, 20 megasrropha, Cardita, 12 Cardila (Strophacardia), 12; pl. 12 Strophocardia, 5 Venericardia, 12 Milneria, 17, 28 kelseyi, 28 minima, 17, 28, 39 minim, Ceropsis, 28 Milnen'a, 17, 28; 1. 9 minuscula, Glans, 15P Miadon prolongatus, 16 Miodontiscus, prolongatus, 12, 16; pl. 5 manilicosta, Cardita, 13 Montacutidae, l, 9 Monterey Shale, 13 montereyana, Cyclocardia (Cyclocardia), 12, 13; 1. 7 Venericardia, 13 Moore, R.C., cited, 1 Morris, R.H., cited, 4, 9 Muir Sandstone, 24 mulleri, Venen'cardia, 19 (Pacificar), 17, 18, 19; pl. 1 Mysella, 5, 9 tumica, 9 (Rocheforu'a) rumida, 5, 9; pl. 7 Myrilus, 5, 6 N Neaeromya, 5, 9 (Orbitella) compressa, 5, 10; pl. 4 nelsoni, Venericardia (Pacificor), 17, 18, 19; pl. 1 nuca, Aligena aequata, 8 O oblongus, Primes, 9 Thecodonta (Prisres), 5, 9; pl. 4 occidentalis, C ardim, 13 C yclocardia. 13 (Cyclocardia), 12.13; pl. 9 Olsson, A.A., cited, I quoted, 11, 12 Orbitella, 1 0 “0rbitella” compresssa, 10 (Orbitella), Neaeromya compressa, 5, 10; pl. 4 oregonerm's, Venericardia (Pacificor), 21; pl. 3 P (Pacificor), 1, 16, 18 Venericardia aragonia aragonia, 18, 24 diabloensis, 17, 18, 20; pl. 5 jaaquinensis, 17, 18, 23; pls. 6, 8, 9 argentea, 27, 38 calafia, 21 calafia, 17, 18, 21; pl. 3 gabbi, 17, 22; pl. 4 Iurmani, 17, 18,20; pls. 2, 4, 5 smanaensis, 17, 19; pl. 1 clarki clarki, 17, 18, 22; popenoei, 17, 18, 2,4;5131. 9 crescentensis, 18 diabloensis, 20, pl. 2 durhami, 20, pl. 2 gabbi, 22 hertleini, 21 , 1. 3 hornii , 17, 1 , 22, 23; pl. 5 cariosensis, pl. 2 Iutmani, 20 susanaensis, 19 Iisa, 22, 23, 24 lulmani, 20 mulleri,17,l8, 19, pl. 1 nelsoni, l7, 18, 19, pl. 1 oregonensis, 21, pl. 3 popenoei, 25 smileyi, pls. 6, 9 susanaensis, 19 taliaferroi, 1, 17, 18; pl. 5 transversaria, 19 vallecitosensis, 25 vokesi, pls. 8, 9 weaverr, 22, pl. 5 Palmer, K. V. W. ,cited, 9 Pancho Rico Formation, l3 Pelecyora acquilatemlis, 26 peninsulare, Basteotia, 11 phylogeny, Glyptoactis, 18 Venen'cardia, 18 Pioo Formation, 14 planicosla, C ardim, 22 1 Venen'cardia, 22 hornii, 22 venturensis, 19, 25 popenoei, Venen'cardia, 25 (Leuroactis), 24 (Pacificor) clarki, 17, 18, 24; pl. 9 papenoei, 25 Pristes, oblongus, 9 (Pristes), Thecodonta oblongus, 5, 9; pl. 4 Procedure, 1 prolongams, Miodon, 16 Miodontiscus, 12, 16; pl. 5 Pseudopythina compressa, 10 (Pseudopythina), Erycina compressa, 10 Purpose and scope, 1 purpurata, Lasaea, 6 R References, 30 Rio Del] Formation, 10, 14, 15 (Rochefortia),9 Mysella tumida, 5,9 pl 9 Rose Canyon Shale, 7, 21, 22, 27 Roseng Formation, 20 Roth, Barry, quoted, 10 rotunda, Kellia, 7 Round Mountain Silt, 8 rubra, Lasaea 6 subviridis, 6 mfescens, Halioris, 28 Sacate Formation, 25 Sakamoto, Kenji, cited, 4 San Diego Formation, 7, 8, 9, 13, 14, 16, 28 San Francisquito Formation, 17 San Pedro Formation, 7,14,15, 16 Sand, 13 sandiegoensis, Cardita, 26 Glyptoactis, 27 \ 4’11 (Claibornicardia), 17,18,26;pls. 1,7 Venericardia, 26 Santa Barbara Formation, 13, 15, 16 Santa Susana Formation, 19, 25 Shale, 20, 24 Saugus Formation, 13 Saul, LouElla, quoted, 25 Malaria, Lasaea, 6 schencla‘, Venen'cardia (leuroactis), 23; pl. 6 Semeloidea, 8 simiana, Venericardia (V enericor), 25; pl. 8 Sisquoc Formation, l3 smileyi, Megacardita (Venericor) aragania, 23 Venericardia (Leuraactis), 23 (Pacificor), pls. 6, 9 Smith, A.G., cited, 4, 6 Sportellidae, l, 10 Squires, R.L., quoted, 28 Stanley, S.M., cited, 4 Stencplax conspicua, 9 Stewart, R. B., cited, 27 q,uoted 16 Sunni, A. M, cited, 12 Strap ocardia megastropha, 5, 11 (Straphocardia), Cardita megastropha, 12; pl. 7 suborbicularis, Chirania laperousii, 7 Kellia, 7 subquadrata, Glans, 15 (Clans), 12, 15; pl. 5 Lazaria, 15 subviridis,Lasaea, 5, 6; pl. 1 Lasaea rubra, 6 superioris, Cardita, 11 (Cardira) 5, 11; pl. 4 swanaensis, Venericardia (Pacificar), 19 calafia, 17, 18,19; pl 1 hornii, l9 swifriana, Corbula (Cuneocorbula) harrisi, 6 Systematics, Pelecypods, 5 T taliaferroi, Venen’cardia (Pacificar), 1, I 7, 18; pl. 5 Tejon Formation, 6, 22, 23, 27, 28 Tellimya rumida, 9 Temblarnia, 8 (Temblornia), Bornia frankiana, 5, 8; pl. 3 triangulata, 5, 8; p.1 3 Thecodonta (Prisles)P oblongus, 5,9; pl. 4 Thompson, T.E, cited, 4 Timms Point Silt Member, 14, 16 Towsley Formation, 13 tramersaria, Venericardia (Pacificor), l9 triangulala, Bornia (Temblornia), 5, 8; pl. 3 ax, tumida, Mysella, 9 (Rochefom'a), 5, 9; pl. 7 Tellimya, 9 mrrita, Loxatrema, 26 Umpqua Group, 20, 21 uvasana, Corbula, 6 Kellia, 5, 6, 7; pl. 3 INDEX V vallecitosensis, Glyptoactis (Venericor), 18 Megacardita (Venericor), 25 Venericardia (Pacificor), 25 (Venericor), 17, 25; pl. 2 Venericardia, 4, I6, 17, 18 acuticastata, 28 argenrea, 19 barbarensis, 13, 15 borealis, 13 clarki, 22, 23 (Cyclocardia) alas/tuna, 14, 39 californica, 13 damenginica, 27, 28 gabbi, 22, 23 (Glyptoactis) domenginica, 27 keenae, 27 marksi, 27 mcmastersi, 26 (Glyptoacn's?) domenginica, 27 hornii, 20, 21, 22, 23 calty‘ia, 21 , 22 clarki, 22, 23 Iurmani, 20, 21 ianensis, 23, 25 joaquinens'is, 24, 25 (Leuroactis) alisoensis, 23, 36 joaquinensis, 23 popenoei, 24 schencki, 23; pl. 6 smileyi, 23 vokesi, 23 lutmani, 20, 22 marksi, 27 megastrapha , l 2 montereyana , l 3 mulleri, l9 (Pacificor) aragonia aragonia,18,24 diabloemis, 17, 18, 20; pl 5 joaquinensis, 17, 18, 2323 pls. 6, 8, 9 argentea, 27; pl. 8 calq‘ia 21 calafia, 17, 18, 21; 1. 3 gabbi, 17,18, 22; 1.4 Iutmani,l7,18, 2 , pls. 2, 4, 5 susamensis, 17, 18, 19, pl. 1 clarki clarki, 17, 18, 22; popenoei, 17, 18, ’2’}; pl. 9 crescentensis, 18 diabloensis, 20; 1.2 durhami,20 , p'l. ,2 henleini, 21; pl. 3 hornii, 17, 18, 22,23; pl. 5 carIosensis, pl. 2 lutmani, 20 smanaensis, l9 lisa, 22,23, 24 Iutmani, 20 mulleri,17, 18,19; pl. 1 nelsoni,17,18; p1.1 aregonensis, 21, pl. 1 E37 popenoei, 25 smileyi, pls. 6, 9 susanaensis, l9 taliqferroi, l, I 7, 18; pl. 5 transversaria, 19 vallecitosensis, 25 vokesi, pls. 8, 9 weaven; 22, pl. 5 planicosta, 22 hornii, 22 venturensis. 19, 25 papenoei, 25 sandiegoensis, 26 (Venericor) carlaseru'is, 25 hornii, 23 simiana, 25,38 valleciwsensis, 17, 25; pl. 2 venturensis, 17, 25; pl. 8 ventficosa, 13, 14 venturensis, 17, 25 weaveri, 23 yalesi, 16 neLi'om', 19 Venericar'dinae, 16 Venericar, 17, 18, 25 (Venericor) Glyptoacn's vallecitosemis, 18 venturensis, 18 Megacardita aragonia smileyi, 23 horm'i carloseru‘rs, 25 joaquinensis, 23 vallecitosensis, 25 Venericardia cariosensis, 25 hornii, 23 simiana, 25, 38 vallea'tosem'is, 17,25; 1. 2 venturensis, 17, 25', pl. 8 veneriformis. Cardita, 16 “Cardita,” l6 Glans (Centrocardita), 12, 16; pl. 7 ventricosa, Cardira, 14 Cyclocardia, l4 (Cyclocardia), 12, 14; pl. 9 Venericardia, 13, 14 venturensis, Glypwactis (Venericor), 18 Venericardia, 17, 25 planicosta, 19, 25 (Venen'cor), 17, 25; pl. 8 Verastegui, Pedro, cited, 27 quoted, 27 Vokes, H.E., quoted, 26 vokesi, Venencardia (Leuroacn's), 23 (Pacificor); pls. 8, 9 W Waring, C.A., cited, 11 weaveri, Venericardia, 23 (Paaficar), 22 pl. 5 Woodring, W.P., cited, 13 quoted, 15 Y yatesi, Venericanfia, 16 Yonge, C.M., cited, 4, 7, 15 PLATES 1—9 [Contact photographs of the plates in this report are available, at cost, from the US. Geological Survey Library, Federal Center, Denver, Colorado 80225] FIGURES 1, 5, 11. 2, 4. 3, 20. 6, 8-10, 12, 13. 14, 16-18. 15, 19, 21. PLATE 1 Venericardia (Pacificor) mulleri Verastegui (p. E19). Holotype CAS/SU 7994. Base of Lodo Formation, California. Paleocene. Lasaea subviridis Dall (p. E6). CAS 043249 (x7.3). San Diego, California. Holocene. Venericardia (Pacificor) nelsoni Verastegui (p. E19). Holotype UCMP 32804. Santa Susana Formation of Zinsmeister (1983), California. Paleocene. Aligena (Aligena) diegoana Hertlein and Grant (p. E7). 6, 8. Paratype LACMP 4548 (x4.5). San Diego Formation, California. Pliocene. 9, 10. Holotype LACMP 4547 (x3.0). San Diego Formation, California. Pliocene. 12, 13. Paratype LACMP 4551 (x4.5). San Diego Formation, California. Pliocene. Kellia catacta Anderson and GD. Hanna (p. E6). Holotype CAS 275 (x3.0). Tejon Formation, California. Eocene. Venericardia (Pacificor) calafia susanaensis Verastegui (p. E19). Holotype CAS/SU 8004. Santa Susana Shale of Verasteg‘ui (1953), Cali- fornia. Eocene. Glyptoactis (Claibornicardia) sandiegoensis (Hanna) (p. E26). 15, 21. Syntype UCMP 30982 (latex). Rose Canyon Shale of Hanna (1927), California. Eocene. 19. Syntype UCMP 30980, latex. impression. Rose Canyon Shale, of Hanna (1927), California. Eocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228»E PLATE 1 VENERICARDIA, LASAEA, ALIGENA, KELLIA, GLYPTOACTIS PLATE 2 FiGUREs 1, 2. Venericardia (Pacificor) calafia lutmani Turner (p. E20). Holotype of Venericardia (Pacificor) durhami Verastegui CAS/SU 8005. Juncal Formation, California. Eocene. 3-5, 7. Venericardia (Venericor) vallecitosensis (Vokes) (p. E25). 3, 4. Holotype of Venericardia (Pacificor) hornii carlosensis Verastegui, UCMP 15619. Domengine Formation, California. Eocene. 5. Holotype UCMP 15614. Domeng'ine Formation, California. Eocene. 7. Paratype UCMP 15615. Domeng'ine Formation, California. Eocene. 8, 9. Venericardia (Pacificor) aragonia diabloensis Verasteg‘ui (p. E20). 8. Paratype UCMP 32799. Meganos Formation, California. Paleocene and Eocene. 9. Holotype CAS/SU 411. Meganos Formation, California. Paleocene and Eocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 2 VENERICARDIA PLATE 3 FIGURES 1-7, 11, 16, 19. Venericardia (Pacificor) calafia calafia Stewart (p. E21). 1, 2, 5, 6. Hypotype CAS 8017 (x0.8) (Verasteg‘ui, 1953, pl. 16, figs. 2, 3;pl. 17, figs. 1, la, 2, 2a). Llajas Formation, California. Eocene. 3, 4. Holotype UCMP 31450. Llajas Formation, California. Eocene. 7, 16. Holotype of Venericardia (Pacificor) oregonensis Verastegui, CAS/SU 8009. Umpqua Formation, Or- egon. Eocene. 11, 19. Holotype of Venericardia (Pacificor) hertleini Verastegui, UCMP 30415. Rose Canyon Shale of Hanna (1927), California. Eocene. 8. Kellia lajollaensis Hanna (p. E6). Holotype UCMP 31036. Rose Canyon Shale of Hanna (1927), California. Eocene. 9, 12. Kellia uvasana (Dickerson) (p. E6). 9. Holotype CAS 276. Tejon Formation, California. Eocene. 12. Hypotype CAS 894 (Anderson and GD. Hanna, 1925, pl. 9, fig. 11). Tejon Formation, California. Eocene. 10, 15. Kellia laperousii (Deshayes) (p. E7). Hypotype LACMP 4623 (Hertlein and Grant, 1972, pl. 44, figs. 11, 19) (x7.0). San Diego Formation, California. Pliocene. 13, 14. Bornia (Temblornia) frankiana Hertlein and Grant (p. E8). Holotype LACMP 4624 (x3.0). San Diego Formation, California. Pliocene. 17, 18. Bornia (Temblorniana) triangulata (Anderson and Martin) (p. E8). Holotype CAS 130 (x3.0). Round Mountain Silt, California. Miocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 3 VENERICARDIA, KELLIA, BORNIA FIGURES 1, 12, 13. 2, 6, 8, 10. 3, 4. 5, 7. 9, 11. PLATE 4 Venericardia (Pacificor) calafia lutmani Turner (p. E20). 1, 12. Holotype UCMP 33133. Umpqua Formation, Oregon. Eocene. 13. Hypotype UCMP 33009. Venericardia (Pacificor) calafia gabbi Verastegui (p. E22). 2, 10. Holotype CAS 686 (x0.8). Tejon Formation, California. Eocene. 6,8. Hypotype CAS 685 (x0.8) (M.A. Hanna, 1925, pl. 39, fig. 1). Tejon Formation, California. Eocene. Thecodonta (Pristes) oblongus (Carpenter) (p. E9). Hypotype LACMP 4630 (x7.0) (Hertlein and Grant, 1972, pl. 44, figs. 9, 13). San Diego Formation, California. Pliocene. Neaeromya (Orbitella) compressa (Dall) (p. E10). Hypotype of Roth (1979). Lower part of the Rio Dell Formation, Cali- fornia. Pliocene. Cardita (Cardita) superioris Waring (p. E11). Holotype CAS/SU 143. Llajas Formation, California. Eocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 4 VENERICARDIA, THECODONTA, NEAEROMYA, CARDITA FIGURES 1. 2, 5. 3, 7, 8. 17, 18. PLATE 5 Venericardia (Pacificor) calafia lutmani Turner (p. E20). Hypotype UCMP 33009. Juncal Formation, California. Eocene. Venericardia (Pacificor) aragonia diabloensis Verasteg‘ui (p. E20). 2. Paratype UCMP 32799. Meganos Formation, California. Paleo- cene and Eocene. 5. Holotype CAS/SU 411. Meganos Formation, California. Paleocene and Eocene. Venericardia (Pacificor) taliaferroi Verastegui (p. E17). 3, 7. Hypotype CAS 7997. 8. Holotype CAS/SU 7996 (x2.0). Dip Creek Formation of Verastegui (1953), California. Cretaceous and Paleocene. Venericardia (Pacificor) clarki clarki Weaver and Palmer (p. E22). Holotype of Venericardia (Paciflcor) weaveri Verasteg'ui CAS/SU 8024. Cowlitz Formation, Washington. Eocene. Cyclocardia (Cyclocardia) barbarensis (Stearns) (p. E15). Lectotype USNM 104045 (x2.0). Santa Barbara, California. Holocene. Glans (Glans) subquadrata (Carpenter) (p. E15). Hypotype LACMP 4539 (x3.5). San Diego Formation, California. Pliocene. Miodontiscus prolongatus (Carpenter) (p. E16). 12, 16. Hypotype LACMP 4544 (x3.0). San Diego Formation, California. Pliocene. 13, 14. Hypotype LACMP 4541 (x3.0). San Diego Formation, California. Pliocene. Venericardia (Paciflcor) hornii (Gabb) (p. E23). Lectotype AN SP 4558. Tejon Formation, California. Eocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 5 VENERICARDIA, CYCLOCARDIA, GLANS, MIODONTISCUS PLATE 6 FIGURES 1-10. Venericardia (Pacificor) aragonia joaquinensis (V okes) (p. E23). 1, 9. 2, 8. Hypotype UCMP 15615 (x0.8). Avenal Sandstone, California. Eocene. Holotype of Venericardia (Leuroactis) alisoensis Verasteg'ui UCMP 30176. Llajas Formation, California. Eocene. Paratype UCMP 15617 (x0.8). Avenal Sandstone, California. Eocene. Holotype of Venen’cardia (Leuroactis) schencki Verastegui, CAS/SU 8003. Santa Susana Formation of Verastegui (1953), California. Eocene. Holotype of Venericardia (Pacificor) smileyi (Vokes) UCMP 15626. Domengine Formation, California. Eocene. Paratype of Venericardia (Pacificor) smileyi (Vokes) UCMP 15627. Domengine Formation, California. Eocene. US. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 6 VENERICARDIA FIGURES 1, 2, 11, 14. 3, 4. 5, 6. 7-9. 10, 12, 13, 16, 18, 20. 15, 22. 17, 19. 21. 23, 24. PLATE 7 Cardita (Strophocardia) megastropha (Gray) (p. E12). 1, 14. Hypotype (Durham, 1950, pl. 16, figs. 6, ll). UCMP 30517. Unnamed Pleistocene strata, Baja California Sur. 2, 11. Hypotype UCMP 30518 (Durham, 1950). Unnamed Pleistocene strata, Baja California Sur. Cyclocardia (Cyclocardia) californica (Dall) (p. E13). Holotype USNM 164558 (x1.5). Santa Barbara Formation, Cali- fornia. Pliocene and Pleistocene. Mysella (Rochefortia) tumida (Carpenter) (p. E9). . Hypotype LACMP 4625. San Diego, California. Pliocene. (Photo- copy of Hertlein and Grant, 1972, pl. 44, figs. 2, 4.) Glans (Centrocardita) veneriformis (Gabb) (p. E16). 7,8. Holotype ANSP 4381 (x2.0). Martinez(?) Formation, California. Paleocene(?). 9. Paratype ANSP 4381a (x2.0). Martinez(?) Formation, California. Paleocene. Glyptoactis (Claibornicardia) domenginica (Vokes) (p. E27). 10, 18. Paratype UCMP 15613 (x2.0). Domengine Formation, California. Eocene 12, 16, 20. Paratype UCMP 15612 (x2.0). Domengine Formation, California. Eocene. 13. Holotype UCMP 15611 (x1.5). Domengine Formation, California. Eocene. Glyptoactis (Claibornicardia) sandiegoensis (M.A. Hanna) (p. E26). Holotype of Glyptoactis (Claibornicardia) mcmastersi Verasteg'ui CAS 8011 (x2.0). La Jolla Group, California. Eocene. Glyptoactis (Claibornicardia) marksi Verastegui (p. E27). Holotype CAS/SU 8021. Live Oak Member of Verastegui (1953), Tejon Formation, California. Eocene. Cyclocardia (Cyclocardia) montereyana (Arnold) (p. E13). Holotype USNM 165464. Monterey Shale, California. Miocene. Cyclocardia (Cyclocardia) crebricostata (Krause) (p. E14). 23. Lectotype Museum der Humboldt-Universitat, Berlin 37934 (Coan, 1977) (x2.0). St. Paul Island, Bering Sea, Alaska. Holocene. 24. Lectoparatype Museum der Humboldt-Universitat, Ber- lin 379311.(Coan, 1977) (x2.0). St. Paul Island, Bering Sea, Alaska. Holocene. PROFESSIONAL PAPER 1228-E PLATE 7 US. GEOLOGICAL SURVEY GLYPTOACTIS GLANS, 7 CARDITA, CYCLOCARDIA, M YSELLA PLATE 8 FIGURES 1, 2, 4, 5, 7, 9, 11, 14. Venericardia (Venericor) venturensis Waring (p. E25). 1, 9. Hypotype CAS 319. Santa Susana Formation, California. Paleocene. ‘ 2, 11. Paratype of Venericardia (Venericor) simiana Verastegui CAS 8002. Santa Susana Forma- tion, California. Paleocene. 4. Hypotype CAS 318. Santa Susana Formation, of Zinsmeister (1983), California. Paleocene. 5, 14. Holotype of Venericardia (Venericor) simiana Verastegui CAS/SU 8001. Santa Susana For- mation, California. Paleocene. 7. Holotype CAS 159. Santa Susana Formation, California. Paleocene. 3. Venericardia (Pacificor) aragonia joaquinensis (Vokes) (p. E23). Paratype of Venericardia (Pacificor) vokesi Verastegui CAS/SU 8016. Avenal Sandstone, California. Eocene. 6, 8, 10, 12, 13, 15. Glyptoactis (Claibornicardia) keenae (Verasteg'ui) (p. E27). 6, 15. Holotype of Venericardia (Paciflcor) argentea Verastegui CAS/SU 7995. Base of Lodo For- mation, California. Paleocene. 8, 13. Hypotype UCMP 33001 (x1.5). 10, 12. Holotype CAS/SU 7992. Base of Lodo Forma- tion, California. Paleocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228—E PLATE 8 VENERICARDIA, GLYPTOACTIS FIGURES 1, 2. 3-6. 7, 15. 8, 14. 12. 16, 18. 17, 19. PLATE 9 Cyclocardia (Cyclocardia) crebricostata (Krause) (p. E14). Holotype of Venericardia (Cyclocardia) alaskana Dall USNM 109271 (x1.5). Bering Sea, Alaska. Holocene. Cyclocardia (Cyclocardia) occidentalis (Conrad) (p. E13). 3, 5. Hypotypes UCLA 48619 (x1.5) (Hertlein and Grant, 1972). San Diego Formation, California. Pliocene. 4, 6. Hypotypes UCLA 48616 (x1.5). San Diego Formation, Califor— nia. Pliocene. Venericardia (Pacificor) clarki popenoei Verastegui (p. E24). Holotype UCMP 15689. “Coldwater” Formation, of Verasteg'ui (1953), California. Eocene. (Photocopy of Verastegui, 1953, pl. 21, figs. 1, 2.) Basterotia (Basterotella) hertleini Durham (p. E10). Holotype UCMP 32274 (x3.0). Comondfi Formation, Baja California Sur. Pliocene. Cyclocardia (Cyclocardia) ventricosa (Gould) (p. E14). Hypotype LACMP 4537 (x1.5) (Hertlein and Grant, 1972, pl. 43, figs. 3, 8). San Diego Formation, California. Pliocene. Cardita (Byssomera) affinis Sowerby (p. E11). Hypotype UCMP 30626. Unnamed Pleistocene strata on Isla Carmen, Baja California Sur. Cyclocardia (Cyclocardia) kirkerensis (Clark) (p. E12). Holotype UCMP 11165 (x2.0). Kirker Tuff, California. Oligocene. Milneria minima (Dall) (p. E28). Hypotype LACMP 4546 (x7.0). (Hertlein and Grant, 1972, pl. 43, figs. 1, 2, 14) San Diego Formation, California. Pliocene. Venericardia (Pacificor) aragonia joaquinensis (V okes) (p. E23). 17. Holotype of Venericardia (Pacificor) smileyi (Vokes) UCMP 15626. Domengine Formation, California. Eocene. 19. Paratype of Venericardia (Pacificor) vokesi Verastegui CAS/SU 8016. Avenal Sandstone, California. Eocene. U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 9 CYCLOCARDIA, VENERICARDIA, BASTEROTIA, CARDITA, MILNERIA 7 DAYS SELECTED SERIES OF U.S. GEOLOGICAL SURVEY PUBLICATIONS Perlodlcals Earthquakes & Volcanoes (issued bimonthly). Preliminary Determination of Epicenters (issued monthly). 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