Devonian Carrier Shells (Euomphalidae) from North America and Germany By ROBERT M. LINSLEY and ELLIS L. YOCHELSON G E01 O L SURVEY PROEESSION AL PAPER 824 A study of a behavior pattern in which foreign matter is attached to the shell of living and Devonian gastropods UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 73-600142 For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 Price $1.15 (paper cover) Stock Number 2401-02370 CONTENTS A. ELC! .e cece cen cl leon nne e sence Systematic paleontology - Continued Introduction and acknowledgments...................... Superfamily Euomphalacea - Continued Implantation among the recent fAUun@............._._._._._._._._._._.__.. Family Euomphalidae - Continued 1 1 2 The 1. ie 3 Genus Straparollus Montfort - Continued 3 4 Habits of Xenophora conchyliophora.. # Subgenus Euomphalus J. Sowerby... Habits of Xenophora neogelanica.................................. Stratigraphic Functional significance of implanted material in Positioning of shell during implantation.... the Distribution and nature of implanted material.................. Implantation in fossil gastropod shells..........._______.___._.___.... Functional significance of implanted material...... Systematic Presence and absence of implanted materials.... Superfamily Euomphalacea. # The status of .. e s ison naan at Family Euomphalidae........................}................2.. Evolutionary groups of Devonian carrier shells.... 0 N1 14 14-1 o oa Genus Straparollus Montfort... Conclusions.... ...... clo a aan Subgenus Serpulospira Cossman.......... pelected references.......................:l.n.....2....... Subgenus Straparollus Montfort... index ..... s... oe ae a a an n na ILLUSTRATIONS [Plates follow index] PLATE 1. Xenophora pallidula Reeve. 2. Xenophora neozelanica Suter. 3. Straparollus (Straparollus) and S. (Serpulospira). 4. Straparollus (Straparollus) . 5, 6. Straparollus (Euomphalus) and S. (Straparollus). Page FIGURE 1. Chart showing stratigraphic occurrence of incrusting evuomphalids.........................._......... 15 2. Drawings showing reconstruction of euomphalids as mobile animals...... 16 3. Drawings showing reconstruction of euomphalids as sessile animals...... 17 III Page DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY By Rosrert M. Linsey! and ELLs L. YOCHELsON ABSTRACT The modern carrier shell Xenophora has an elaborate be- havior pattern in which the gastropod attaches foreign mat- ter to its shell. The process is a long and deliberate one that has selective significance in terms of visual and olfactory camouflage. Besides the Xenophoridae, first certainly known from the Cretaceous, one turritellid in the Miocene-Pliocene and one Miocene modulid mastered this peculiar art. Various members of the Euomphalacea from the Ordovician, Silurian, and Devonian implanted shell fragments. The systematic part of this report consists primarily of de- scriptions of the known Middle and Late Devonian carrier shells of North America; it includes a discussion of eight species, five of which are new. The new species are Strapa- rollus (Straparollus) mortoni, S. (Straparollus) cottrelli, S. (Euomphalus) hoff mani, S. (Euomphalus) winnipegosis, and S. (?Euomphalus) incrustatus. Specimens of the type species of Philoxene and two related forms were also studied. The Devonian carrier shells are of two or more separate evolutionary stocks having different stratigraphic ranges. One group implants foreign matter regularly; in the other, this feature is quite irregular. Both groups include species having individuals that do not implant material. In both living and fossil carrier shells, the animals show little preference in materials selected except on the basis of size. The implanted material probably served primarily as tactile camouflage as well as visual camouflage. Philozxene Kayser is based on implantation and is here re- garded as based on a spurious concept. The type species should be placed in the Straparollus senso stricto and other species distributed under various subgenera of Straparollus ; implantation alone seems a poor criterion for discriminating a species. The species studied in this paper are treated under three subgenera: Straparollus (Straparollus), S. (Serpulo- spira), and S. (Euomphalus). Species of S. (Euomphalus) in which implantation occurs seem to indicate that the angu- lated whorl profile characteristic of this taxon evolved more than once in time. INTRODUCTION AND ACKNOWLEDGMENTS Kayser (1889, p. 292) established the genus Phil- oxzxene and designated Euomphalus laevis Archiac and Verneuil (1842) as type species. The genus was judged distinct from other euomphalid gastropods because individuals attached foreign matter, usually shell fragments, to their shells. As Knight (1941, 'Department of Geology, Colgate University, Hamilton, N.Y. p. 241) noted in his comprehensive study of Paleo- zoic gastropod type species, the holotype of E. laevis does not have any foreign material attached to its shell. Other specimens, which are presumably con- specific, to some degree do cement shell material to their shells. Examination of topotypic material of the type species of Philozene and of all the available Devo- nian species in North America that attach foreign material suggests that this peculiar habit may be indulged in by individuals within a population but is not necessarily followed by all members. Our study has also demonstrated that the implantation of for- eign matter on the shell is not restricted to a par- ticular shell form but cuts across the lines of three currently recognized subgenera. These observations raise questions concerning the taxonomic, functional, and stratigraphic significance of this particular trait as well as the biologic validity of Philozene. In an attempt to understand the problems presented by these Devonian forms, we have examined the modern carrier shell Xerophora and the closely related T- gurium. The present study is a fusion of interests origi- nally derived from two separate geographic areas. More than a decade ago, M. H. Staatz, U.S. Geologi- cal Survey, submitted for examination a collection from Nevada which was later identified as Philoxene. The effort required to transport a large block of limestone for acid treatment from an area difficult of access is cordially acknowledged. For the past 10 years, Linsley has been engaged in a study of the gastropod fauna of the Rogers City Limestone. Access to the Calcite quarry, Michigan Limestone Operations, U.S. Steel Corp., at Rogers City, Mich., and to the Presque Isle Corporation quarry (formerly Lake of the Woods quarry) north of Alpena, Mich., managed by Mr. Roy Hutchison for a consortium of steel companies, has always been graciously granted. Field investigations in 1966-69 were supported by the Research Council of Colgate 1 2 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY University. In addition, during 1965, the National Science Foundation provided a grant to support a collecting trip by 10 high school students under Lins- ley's supervision. Further, the Research Council of Colgate University provided an Undergraduate Re- search Participation Grant which permitted John Cottrell and John Hoffman to assist with fieldwork. Naming of two species after these assistants is a partial acknowledgment of the calibre of help they provided throughout the various stages of this inves- tigation. Specimens were generously loaned by Dr. Roger Batten, American Museum of Natural History (AMNH). Large collections were lent for study by the Museum of Paleontology, University of Michi- gan (UMMP). Dr. G. M. Ehlers, University of Michigan (deceased), first introduced Linsley to the Rogers City Limestone and was an indefatigable collector and field companion. An unusual specimen from New York was donated by Dr. H. B. Rollins, University of Pittsburgh. G. Arthur Cooper, U.S. National Museum, has repeatedly given us choice specimens and has been a constant source of strati- graphic information. Access to the collections of the Division of Mollusks, U.S. National Museum, has been unlimited, and the staff, particularly J. P. E. Morrison, have shared their knowledge with us. Drs. C. M. Yonge, University of Edinburgh; E. C. Jones, Bureau of Commercial Fisheries, Honolulu; and E. Alison Kay, University of Hawaii, also discussed living forms in some detail with one or both of us. In 1971, the Colgate Research Council provided support that enabled Linsley to spend 2 months at the Department of Zoology, University of Auckland, New Zealand, studying living Xenophora under the general direction of Dr. J. E. Morton. Collections of living material were made possible by Dr. Hinde of the Marine Department, Bureau of Fisheries, New Zealand, who placed the research vessel Ikatere (Captain Turner) at Linsley's disposal. Two stu- dents from the University of Auckland, Roger Grace and Anthony Ayling, provided Linsley with sorely needed expertise during this cruise. In addition, Grace assisted in setting up the aquariums and pro- vided photographic equipment for this phase of the study. Many members of the faculty of the Zoology Department of the University of Auckland provided hours of stimulating discussion of the problems that arose during this part of the investigation. How- ever, we most particularly thank Dr. Morton for his critical reading of the manuscript and for the many hours he spent sharing with Linsley his thorough knowledge of gastropods in general and of the Xeno- phoridae in particular. IMPLANTATION AMONG THE RECENT FAUNA The incorporation of foreign bodies into the hard parts of an organism is not a common trait, but it is widespread in a systematic sense. Some Forami- nifera have apparently been building an agglutinated test (Towe, 1967) since the Cambrian; other Fo- raminifera may imbed foreign grains in a calcium carbonate test. A few tunicates and sponges aggluti- nate sand grains in their flesh, in part, perhaps, accidentally. Worm burrows may be formed of grains of sand bound by mucus, and many worms that live on the bottom construct tubes of clastic grains. Fresh-water caddis fly larvae and terrestrial bagworms are well-known examples of makers of agglutinated tubes. Several animals, such as the "decorator crab," which transfers living sessile or- ganisms to its carapace, are peripheral to those that actually do incorporate material into the shell. The implantation of foreign material is wide- spread within the living Mollusca. One living marine pelecypod, Samarangia quadrangularis, Adams and Reeve (see Clench, 1942), attaches sand grains to its smooth shell to such an extent that the nodes and ribs of sand grains cause it to resemble Echinoch- ama. This form is found only off Japan. All other mollusks known to implant foreign material in their shell are Gastropoda. Among this class, Serpulorbis sp., a vermetid from Hawaii (E. Alison Kay, oral commun., 1971), and Scaliole A. Adams (1880), a recent diastomid from the western Pacific, select and implant only sand-sized grains in their shell, whereas Xenophora and Tugurium use a variety of sizes of material. Scaliola is widespread in the Indian and western Pacific Oceans, and it uses whatever grains are present in the environment. Thus, populations from Bikini and from Wednesday Island implant only sand-grain-sized particles of calcite, whereas populations off Japan utilize grains of quartz or black minerals (J. P. E. Morrison, oral commun., 1970, and examinations of mollusk collections of the U.S. National Museum). The Hawaiian species of Serpu- lorbis implants calcareous sand grains, presumed to be the only grains available in their environment. This discovery of implantation by Serpulorbis is new, and there has not been any detailed investiga- tion as yet. Members of two genera of land snails also com- monly incrust their shells with foreign matter. Thysanophora horni (Gabb) and T. imcrustata (Poey) of the Family Sagdidae commonly affix soil and fecal matter to their shells by agglutinating it with mucus which they secrete (Pilsbry, 1940, p. 985; Clench, 1942, p. 74). Gastrocopta pentodon (Say), a member of the Pupillidae and a common dweller in P:. THE XENOPHORIDAE 3 leaf mold in the eastern part of the United States, also uses mucus to agglutinate soil and fecal matter to its shell (J. P. E. Morrison, oral commun., 1970). Both Thysanophora and Gastrocopt« have white shells, and the attachment of foreign materials does render their shells less conspicuous in the leaf-mold habitat. This action is more related to activities like those of the "decorator crab" than it is to true im- plantation of material. Some Cassis have a very thick and featherylike periostracum to which mud adheres, and the mud serves as camouflage (J. P. E. Morrison, oral commun., 1970). There may be other living forms that camouflage the periostracum. Although this serves the same effect in obscuring the general shape as does attaching matter directly to the shell, it is most unlikely that evidence of such a habit would be preserved in the fossil record. Xenophora and Tugurium are worldwide in dis- tribution in tropical and subtropical waters. Because of their success and because they are so firmly fixed in the popular literature of shell collecting as "carrier shells," it is appropriate that they be considered in more detail. THE XENOPHORIDAE The family Xenophoridae consists of more than two dozen living and extinct species. Wenz (1940, p. 905-909) placed this family in the Strombacea; it includes the extinct genus Endoptygma and ques- tionably the Jurassic genera Jurassiphorus and Lamelliphorus, as well as two living genera. Sohl (1960, p. 96) placed the Late Cretaceous Endo- ptygma in synonymy of Xenophora. Although Juras- siphorus and Lamelliphorus have the same general conical shape as Xenophora, apparently these fossil forms lack all evidence of implantation, and they may not be related. Cox (in Morton, 1958, footnote on p. 100) independently reached the conclusion that these two genera have questionable relationship to the Xenophoridae. The two modern genera that constitute the Xenophoridae are Xenophora Fischer von Waldheim and Tugurium P. Fischer (in Wie- ner). Morton (1958, p. 96-100) argued convincingly that the Xenophoridae are more closely related to the Calyptreacea than to the Strombacea. The species of the genus Xenophora, as deter- mined from examination of shells of the living X. conchyliophora Born, X. corrugata (Reeve), X. pal- lidula (Reeve) (pl. 1, figs. 1-5) - perhaps the most striking of the modern carrier shells -X. caperata Philippi, X. konoi Habe, and X. neozelanica Suter (pl. 2, figs. 1-5), and others are all characterized by an abundance of incrusted foreign matter. Tugurium is divided into three subgenera: Tu- gurium (Tugurium), T. (Trochotugurium) Sacco, and T. (Haliphoebus) P. Fischer (in Wiener). In contrast to Xenophora, the genus Tugurium has lit- tle, if any, implanted matter. Shells of modern spe- cies that were examined include especially T. (T.) exutum (Reeve), T. (Trochotugurium) borsoni (Bel- lardi), T. (Trochotugurium) longleyi (Bartsch), T. (Trochotugurium) caribeum (Petit), and T. (Hali- phoebus) solaris (Linneaus). These forms have evolved a frill that extends from the periphery down over the base much like a skirt. T. (Haliphoebus) solaris is a most handsome shell whose frill has been modified to consist of long, slender spinelike extensions from the periphery. In its youthful stages, this species implants foreign material not unlike a typical Xenophora. When spines begin to form by the third or fourth volution, the organism loses the implanting habit. In T. (Trochotugurium) indicum (Gmelin), T. (Trochotugurium) helvacea (Phillippi), and- T. (Trochotugurium) borsoni (Bellardi), implantation only occurs in the youthful stages. Again, after three or four whorls, the skirtlike frill forms, and no fur- ther implantation takes place. In T. (Trochotugu- rium) longleyi (Bartsch) and T. (Trochotugurium) calculiferum (Reeve), a frill forms, and the im- planting habit continues throughout the life of the individual. The size and amount of implanted mate- rial is very small, however, as compared with that used by Xenophora, so that the shell is neither sup- ported nor hidden by the incrusted material. In all the Xenophoridae that we have examined, save one, foreign matter is implanted at the lower edge of the outer whorl face. In T. (Trochotugurium) lam- berti souverbie, however, material is implanted at the suture (the upper edge of the outer lip) rather than at the periphery (lower edge of the outer lip). The habit persists throughout the life of the indi- vidual, but again the implanted material neither supports nor hides the shell. In T. (Tugurium) exutum (Reeve), mature indi- viduals rarely show any implantation, and only a few individuals in the collections of the U.S. Na- tional Museum show some implantation in the very early whorls. The margin of the frill is sinuous so that it appears to have broad, blunt "spines" or flanges. HABITS OF XENOPHORA CONCHYLIOPHORA Most of the Xenophoridae live below wave base and are commonly reported in depths of 100 to 1,000 feet. As a result, much of our information about - them is based on shells dredged from the ocean floor, 4 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY and opportunity for first-hand observation has been limited. However, Xenophora conchyliophora occurs at quite shallow depths in Florida. Mr. Paul Shank managed to keep specimens alive in aquariums for 2 years. According to Shank (1969), X. conchylio- phora spends most of its life withdrawn within its aperture and feeds on microscopic algae by extend- ing its proboscis to the substrate. Thus it does not place its entire foot on the substrate in order to feed. "When food is plentiful it never reaches beyond the limits of its shell, but feeds entirely on the material beneath its shell" (Shank, 1969, p. 5). Further (Shank, 1969, p. 6), X. conchyliophora buries its feces by forcing the substrate apart with its propodium and probocis, placing the feces in the hole, and using its proboscis to rake the hole shut. Mr. Shank is one of the few people who have been able to observe the process of cementation at first hand. His account of the process is herein quoted in its entirety (Shank, 1969, p. 6) : The placing of the rubble isn't merely a matter of position- ing shell against it and cementing it fast but a meticulous job on the part of the mollusk. The rubble is turned over, twisted around, or upended to get it into the exact position whereas [sic] it has a downward slope in relation to the shell. It is also brought into contact with the mantle and usually in such a position that the weight of the shell is par- tially holding it in position. The Xenophora uses its head and proboscis placed below rubble to raise it into place and its foot to raise and lower its shell at the same time, jockeying the two into position. Rubble is not turned by clasping be- tween the propodium and metapodium as I have read but rather it is clasped between the base of the antennae and the proboscis. Flat pieces are actually picked up in this manner while the mollusk is standing on its foot holding its own shell up so rubble can be worked to a more suitable position be- neath the previously attached rubble. Up to an hour and a half is sometimes spent getting the rubble into position. Sand is raked from under the rubble with the proboscis to assure more slope and consequently leave more space beneath the shell after attachment is completed. After rubble is finally jockeyed into a suitable position the job is still not finished. The Xenophora then carefully cleans all the area coming in contact with the mantle to insure a tight joint during the process of cementing it fast. Gaps are checked between the mantle and rubble and filled in by stick- ing pieces of sand and tiny pieces of debris to the mantle edge by cleaning them and placing them there with the pro- boscis, one piece at a time. Occasionally, it sticks its head and proboscis under rubble for support and very gently rocks shell to and fro, evidently checking rubble for security of attachment. With the larger pieces of rubble the mollusk remains stationary for over ten hours to assure a tight bond before resuming its food hunting. HABITS OF XENOPHORA NEOZELANICA In 1971, the senior author had the privilege of spending 2 months with Dr. John Morton, Depart- ment of Zoology, University of Auckland, New Zea- land. Specimens of Xenophora neozelanica Suter, were dredged off New Zealand. These were kept alive for study in aquariums at the Zoology Depart- ment for more than 4 months. Young Xenophora neozelanica Suter have a pre- dominantly white body ; orange pigmentation forms primarily in the region of the proboscis and tenta- cles. In the adult organism, the entire upper surface of the foot is bright orange, and this color extends well up the muscular column inside the shell. This column is essentially circular in cross section and remarkably protrusible (pl. 2, figs. 2, 4). The proboscis is well developed in Xenophora, very extensible and quite muscular (pl. 2, figs. 1, 3, 5). It is flanked by two long tentacles, and the eyes are on slight swellings at the base of the tentacles. These tentacles are moderately muscular and were observed to hold lightweight objects being scraped by the radula. However, they were never observed lifting shell material for implantation as has been described for Xenophora conchyliophora (Shank, 1969, p. 6). The foot is keyhole shaped, having a constriction between propodium and metapodium (pl. 2, fig. 5). The propodium is very broadly expanded laterally. The flat plantar surface of the metapodium is con- tinuous with that of the propodium and is narrower than the propodium but has not been reduced to a narrow median keel (Morton, 1958, p. 91). The operculum is on the posteriormost part of the foot, and the metapodium expands at the back to accom- modate this broad structure (pl. 2, fig. 5). The operculum is conchyolin and noncalcified. It is subtriangular, the base of the triangle extending out over the rear of the metapodium to engage the substrate. The operculum has almost no curvature. Its central area has a narrowly triangular muscle scar extending from the apex almost to the base. According to Morton (1958, p. 93), "the food of the Xenophora neozelanica Suter is very bulky and consists of the surface layer of grey muddy silt * * * with organic constituents living and dead." Perhaps as a result of having to process such large quantities of material through its gut, X. neogelanica shows greater activity than that described for X. conchylio- phora. Its foot was frequently in contact with the substrate. Thus, this species of Xenophora is as close to being an unselective deposit feeder as any mollusk, and its feces are therefore of large bulk. X. neozelanica was not observed to bury its feces as has been reported for X. conchyliophora. However, observation of this habit is uncertain, for it is very difficult to observe activities going on under the "tent flaps" of implanted material. Movement by Xenophora is generally described as THE XENOPHORIDAE 5 a "leaping" motion (Morton, 1958, p. 91), but It more closely resembles a one-legged stomp. The plantar surface of the foot is placed against the substrate, and the shell is lifted by extension of the muscular column. Next the shell is thrust forward for about half its diameter, and it then falls forward. When the foot is being lowered to the substrate from its retracted position, the operculum is pointed straight down as though it would dig into the sub- strate. However, in observing the movement of X. neozelanica against a wide variety of substrates, the operculum was always found to be flat against the substrate, in the same plane as the plantar sur- face of the foot. The motion in Xenrophora is sudden and discon- tinuous. This is consistent with the motion of other like-camouflaged organisms, for slow, continuous motion would draw attention to them. It also results in a discontinuous track which would tend to thwart predatory organisms using olfactory senses to "sniff out a trail." Normal locomotion of the strombids is to crawl along the substrate, but they are also capa- ble of an escape motion by digging the operculum into the substrate and then flinging the body for- ward. Xenophora neozelanica did not show such a reaction, nor has it been seen to crawl. Specimens placed in the presence of starfish (Cos- cinasterias) and a variety of oyster drills showed no change in their motion. The general reaction of Xenophora to these predators was one of apparent unconcern. They did not even withdraw into their shells but continued to feed and move even though the drills or starfish were directly atop them. The force provided by the extension of the mus- cular column is surprisingly great. Many Xenophora shells were incrusted by masses of organisms whose entire weight exceeded that of the shell itself, yet they were able to lift it without any difficulty. Indi- viduals moved even though two or even three other Xenophora were piled on top of them. The incrusting organisms could be located asym- metrically to one side of the shell, creating con- siderable imbalance, but the carrier shell had no difficulty in compensating for this. The muscular column is capable of remarkable extension, equal to at least the height of the shell. This extension is utilized when the edge of the shell becomes propped up on some object, when a tipped-over shell is righted, when foreign matter is affixed to the shell, and, presumably, during copulation, although the last has never been witnessed. This extension is apparently accomplished by contraction of the cir- cular muscles around the body stalk forcing blood into the pedal haemocoel. The method of manipulation and implantation of foreign material proved to be completely different in Xenophora neozelanica than in X. conchyliophora. The tentacles of X. neogelanica do not appear suffi- ciently muscular to handle the large shells normally implanted by adult shells. Young specimens might use this method, although it seems more likely that individuals would consistently use the same tech- nique throughout their growth. In adults, when the time comes to attach new shell material, the animal turns upside down beneath its tentlike shell so that - the plantar surface of the foot is directed upward and the proboscis is placed against the substrate (pl. 2, fig. 4). The organism can still maneuver with full effectiveness by pushing down against the sub- strate with its proboscis. It can easily make adjust- ments in positioning the shell while in this attitude and occasionally even take "steps." This position now places the foot in an ideal position to search the environment for a shell suitable for implantation. During the search, the animal is capable of extend- ing its body far out from under its shell (pl. 2, fig. 2). The foot searches among various available shells for an appropriate one to be placed in position for cementation. From the search behavior, the criterion for selection is thought to be primarily one of size. The materials available in the aquarium consisted of either limestone pebbles or bivalve shells, and both were selected by different individuals. The one distinction that was obviously made was between bivalve shells that were concave side down in the substrate and those that were convex side down. Those that were concave side down were flush against the bottom and proved very difficult for the carrier shell to pick up with its foot. Those that were convex side down were easy to pick up. When an object was picked up, the plantar surface of the foot crawled under, using the wavelike muscular contrac- tion typical of most gastropodal locomotion. These contractions of the foot were only seen in Xenophora when shells were picked up for implantation and when an inverted shell was righted, whereupon the foot was used to "crawl" into the substrate for pur- chase. Once the carrier shell grasped the foreign object for implantation, it maneuvered its own shell into position for the process by pushing down against the substrate with its proboscis, while the propodium brought the foreign shell into appropriate position. A pelecypod valve would be leaned against the car- rier shell concave side outward. The mantle then cemented the valve into place. Unfortunately it was impossible to observe the conclusion of this process in Xenophora neozelanica, but it is presumed to be similar to the concluding phases of cementation in Xenophora conchyliophora. 6 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY FUNCTIONAL SIGNIFICANCE OF IMPLANTED MATERIAL IN THE XENOPHORIDAE There can be little doubt that the implanted ma- terial on shells of the Xenophoridae serves as camou- flage. The behavior of the organism is consistent with this function. Discontinuous and occasional movement, intermittent placement of the foot on the substrate, and burial of the feces are all traits con- sistent with animals that depend upon hiding. This gastropod has probably evolved both visual and olfac- tory camouflage by these behavioral features. The implanted material seems to have a second function which might be even more significant than camouflaging. In the genus X enophora, the implanted foreign material is positioned so that the pieces act as stilts which lift the entire base and the aperture up off the substrate. In the closely related genus Tugurium, this stiltlike function of the implanted material is supplanted by the presence of a frill (in T. (Tugurium) and T. (Trochotugurium)) or long spines (in T. (Haliphoebus)). In Tugurium, the im- planted material is present only in immature speci- mens where it would seem to be functional prior to 'the formation of the frill. In the adult stage, the implanted material is either completely absent or is reduced in amount so that it is nonfunctional in raising the shell above the substrate. We would sug- gest that once the implanted material was acquired, further selection for it in terms of camouflage effect would take place. The eventual stiltlike function which originally provided at least some olfactory camouflage became equal in importance through continued evolution of the group. The genus Tugu- rium would then be a deep-water adaptation where olfactory camouflage was more important than visual camouflage. As a result, the tentlike frill and spines were sufficient to replace the implanted material as a means of lifting the soft parts of the gastropod off the substrate. The geologic record of the group supports the notion of a later appearance for the more advanced Tugurium. IBIPIAAPJTHX1FHDPJIPJIN)SSII.(}AS1FRJ)P()I)SIlEIJQS In reviewing the literature concerning Devonian Philoxene, references were found to other gastro- pods that have a Xenophora-like habit, and it seems appropriate to mention these additional forms. Spe- cies of Xenophora are known from Late Cretaceous to Holocene; Cossmann (1915, p. 187) stated that the typical subgenus of Tugurium is not known as a fossil, though subsequently it has been found in Mio- cene rocks of the Pacific region (MacNeil, 1960, p. 47). The few Cretaceous and Tertiary fossil forms of this family that we have examined show the char- acters of this group in a consistent manner. Psammodulus Collins (1934), a member of the modulids, occurs in the middle Miocene of Tehuan- tepec, Mexico. This form is comparable to the living Sealiola in that the small animal uses only grains of sand size. It shows a fair degree of selectivity by using only quartz. The average size of grains in- creases as shell size increases. In general, the grains are attached in rows crudely paralleling the aper- ture. Springvaleia Rutsch (1943) is a most unusual turritellid from the Miocene of Trinidad and Plio- cene of Venezuela (Woodring, 1958; Weisbord 1962, p. 150-152). It appears to be unique among the turritellids in being the only member of a very large and successful family to effect a Xenophora-like facade of implanted shell material. The camouflage appears to be quite good in that an estimated 70-80 percent of the original shell is hidden by the incrust- ing material. Most of this material consists of frag- ments of mollusks, bryozoans, barnacles, and even flat rocks. Devonian species that might be ascribed to Phil- oxene are discussed in some detail in the section "Systematic Paleontology." In reviewing the genus, Cossmann (1915, p. 148-149) listed the type and only one other species, the Middle Devonian Euomphalus serpens Phillips, as redescribed under Philoxene by Whidborne (1891, p. 241, pl. 24, figs. 1-5). This species, as illustrated, does show small, closely spaced impressions so high on the whorl that they are just below the upper whorl surface. They are quite atypi- cal of the scars on all other forms that we have studied directly. Whidborne does illustrate specimens of Philoxene laevis that show more characteristic cicatrices. He also described and illustrated the spe- cies Philoxzene philosophus, which has prominent cicatrices; for some reason, this species was over- looked by Cossmann. Because we have no specimens of these two species in hand, we have excluded them from the systematic section and in fact have limited our studies primarily to North American forms. The only other Paleozoic gastropod known to im- plant foreign material into its shell is Lytospira. Although this open-coiled euomphalid was first named from the Middle Ordovician of Scandinavia in 1896 (Koken, 1896, p. 398), its author did not make mention of an imbedding habit. Koken (Koken and Perner, 1925, p. 112) eventually did note "mehrere Arten bekleben sich mit fremden Schalen- stuckchen ete. nach Art der Phoriden.'" In the in- terim, species were described from the Silurian of Bohemia, at least one of which, Lytospira subuloidea Perner (1907, p. 143, text fig. 180), shows irregu- larities, presumably from shell matter embedded SYSTEMATIC PALEONTOLOGY 7. near the periphery. No illustrations of other species described from the Ordovician and Silurian of both areas show any cicatrices. Yochelson (1963, p. 179) restudied Lytospira norvegica Koken and confirmed that this species does bear scars from attachment of foreign matter (Yochelson, 1963, pl. 5, fig. 7). However, at the time he did not study the possible individual varia- tion in implantation within the available specimens of one species. In retrospect, the only additional comment is that scars, if they were present on many of the specimens, were few and were widely spaced ; the point should be investigated. Yochelson (1963, p. 179) also erred in that, although he thought that the widely disjunct (open-coiled) form indicated a sedentary life habit, he ascribed an active mode of life to Xenophora because of its efforts in collecting shells and, by inference, transferred this same pre- sumed activity to L. norvegica. In the Middle Ordovician of the United States, Ulrich and Scofield (1897, p. 1036-1037) redescribed Ececyliomphalus undulatus Hall, a widely open-coiled species. They noted that "depressions on the outer side of the shell are due to agglutinated foreign ob- jects like fragments of Orthis." Another widely disjunet Middle Ordovician species, Cyrtolites tren- tonensis Conrad, transferred to Ececyliomphalus by Weller (1903, p. 184), is represented in the collec- tions of the National Museum by four specimens. On the best preserved of these, several attachment scars are evident. The types of both species have not been investigated. The relationship between Lyto- spira and Eecyliomphalus remains to be clarified, but presence or absence of incrusting material would be an unsatisfactory character to use in distinguish- ing these genera. Widely disjunct gastropods should be examined to see if other species have the habit of implantation. SYSTEMATIC PALEONTOLOGY Superfamily EUOMPHALACEA Family EUOMPHALIDAE Genus Straparollus Montfort Subgenus Serpulospira Cossmann Straparollus (?Serpulospira) eboracensis (Hall) Plate 3, figures 19-21 Euomphalus eboracensis Hall 1861, p. 27; Hall 1862, p. 55, Hall 1876, pl. 16, figs. 19-23. Euomphalus (Phanerotinus) eboracensis Hall 1879, p. 61, pl. 16, figs. 19-23. Description. - Moderately large discoidal gastro- pods with rapidly expanding whorls and disjunct coiling of the adult whorl. Early whorls poorly known. Aperture poorly known, apparently subcir- cular to elliptical in cross section ; growth lines indi- cate a simple prosocline aperture. Sutures very deep in early whorls, later whorls slightly disjunct; upper and outer whorl face rounded and continuous below periphery; lower part of outer whorl face flattened locally by adpressed foreign material; slight angulation at base of attachment zone sepa- rating outer and basal whorl faces; base unknown; umbilicus unknown, presumably widely phanerom- phalus. Growth lines faint. Foreign matter attached at or below periphery with irregular spacing. Shell structure unknown, apparently moderately thick. Discussion. - Hall (1861, p. 27) described some rather poorly preserved shells "In the shales of the Hamilton Group at Eighteen-mile Creek in Erie County and at York, in Livingston Co., N.Y." as Euomphalus eboracensis. The specimen illustrated herein was loaned by Dr. Roger Batten, American Museum of Natural History (AMNH). It has a width of 30.9 mm and height of approximately 11 mm. This is a most perplexing specimen. Hall's original designation of this specimen as Phanerotinus has nothing to support it, for there is no trace of the leaflike expansions that are diagnostic of that genus. However, our placement of this species in the sub- genus S. (Serpulospira) is also questionable. As far as we can judge, the whorls are disjunetly coiled, but the whorl diameter increases more rapidly than is typical in S. (Serpulospira). The specimen is also different from other species described herein in that it has used primarily brachiopod fragments as the implanted material, though this is an indication of a different habitat rather than a different habit. The collections of the American Museum of Natu- ral History contain two specimens of this species both under number g Whitfield and Hoovey (1900, p. 312) designate this number as "type." The specimen figured here is that illustrated by Hall (1876, pl. 16, figs. 19 and 23 ; refigured in Hall, 1879, pl. 16, figs. 19 and 20). The specimen is designated here as lectotype so as to avoid any further confu- sion ; it is apparent that Hall's drawings have been somewhat idealized. The lectotype is from "York." The other specimen, from "Eighteen-mile Creek" in Erie County, is an indeterminate steinkern which may be a euompha- lacean. In the 1876 and 1879 works, no mention is made of an occurrence other than at York. Collec- tions have not been made at the "York" locality, which is most probably in the Middle Devonian Lud- lowville Formation, (G. A. Cooper, oral commun., 1972). Numbered specimen. - Lectotype: AMNH$819~O s 8 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY Straparollus (Serpulospira) centrifuga (F. A. Roemer) Plate 3, figures 8-11 Discussion. - One specimen (USNM 183651) col- lected from the Paffrath beds near Bergische Glad- bach near Cologne, Germany, by R. M. Linsley and Ulrich Jux, is a typical example of Straparollus (Serpulospira). However, it is unusual in that it shows shallow implantation scars at the whorl pe- riphery. A second specimen (USNM 63406), which was purchased many years ago from a professional collector, is from the Paffrath "near Cologne" Ger- many and could be from the same locality. This specimen, labeled S. (Serpulospira) serpula Koninck, also shows similar cicatrices, but it is fragmentary and not worth illustrating. Other specimens of this species that we have studied show no evidence of implantation. These two specimens resemble S. (Straparollus) laevis and S. (Straparollus) ?laevis, also from the Paffrath beds, in general whorl cross section. In all, the implantation sears show a marked regularity in both size and spacing, especially when contrasted with the irregularity of the cicatrices of some North American Devonian carrier shells. The attachment sears are at or slightly above the shell periphery. The species Straparollus (Serpulospira) centrif- uga (Roemer) was originally described under Serpularia and considered to be a worm tube. Sub- sequently, additional specimens were described as Euvomphalus serpula by de Koninck (1843, p. 425- 426). De Koninck included both Middle Devonian and Lower Carboniferous open-coiled forms within the same species. Later authors have transferred specimens of both ages to other genera, including such widely different taxa as Solarium, Straparollus, and Pleurotomaria. Constructing a meaningful syn- onymy for this taxon is almost a hopeless task; many of the earlier illustrations have been repeat- edly reproduced in textbooks with few additional new data. It is pertinent to note that illustrations of this species given under its various names by various workers show no attachment scars. These illustra- tions include those of de Koninck (1843, pl. 23 bis., figs. Sa, 8b; pl. 25, figs. ba, 5b) ; Goldfuss (1844, pl. 191, figs. la-le) ; and Sandberger and Sand- berger (1850, pl. 25, fig. 9). As noted, the attach- ment scars we have observed in this species are obscure; that they are not shown in drawings does not necessarily mean that they were consistently absent. Even if all previously described and illus- trated specimens lack foreign particles, or at least their attachment scars, the biological situation would be no different from that in S. (Straparollus) cyclostomus (Hall) (p. 10). In both instances, most members of the presumed populations lack any indi- cation of attachment, but a few individuals do main- tain this habit. Numbered specimen. - Hypotype: USNM 183651. Subgenus Straparollus Montfort Straparollus (Straparollus) laevis (Archiac and Verneuil) Plate 3, figures 1-3 Discussion. -Three specimens of this species - numbered 58498 and 183680 (two specimens in one lot) and 63256 - are in the collections of the U.S. National Museum ; both lots were obtained years ago from the Paffrath near Cologne. All these specimens differ from the holotype described by Knight (1941, p. 241) in having abundant sears of attachment. In the figured specimen, the nuclear and juvenile whorls are free of any signs of incrusted material. However, the final three whorls show sears indicating the im- plantation of foreign matter. The implantation sears are peripheral on the body whorl but are slightly above the periphery on the penultimate whorl. The implantation of material higher on the penultimate whorl would seem to be an adaptation which allows the body whorl to become emplaced in a subplani- spiral position, the suture immediately at the base of the implantation sears. This also suggests that the specimen is probably mature, for another whorl could not maintain the nearly planispiral form with- out interference from the implanted material. Knight (1941, p. 242) indicated the presence of a parietal inductura. His illustration of the type speci- men shows that the body whorl has been broken back for some distance ; the impression of the parietal lip on the base of the penultimate whorl may have mis- led him into interpreting this as an inductura. Although the type specimen does have an upper angulation across which the growth lines are sinu- ate, both the angulation and the sinus are exceed- ingly obscure features. The differences between the holotype and the specimens we have examined are so slight that they fall well within the range of variation to be expected in any population of Strapa- rollus. What is significant is the absence of scars of attachment on the type and their obvious presence on conspecific material. Because this is a common and well-known Euro- pean species, which has been cited repeatedly, we have not made any attempt to construct a formal synonymy. Numbered specimens.-Hypotypes: USNM 58498 (figured), 63256, and 183680. SYSTEMATIC PALEONTOLOGY 9 Straparollus (Straparollus) ?laevis (Archiac and Verneuil) Plate 3, figures 4, 5 Discussion. - One specimen in the collection of the U.S. National Museum (63255) is labeled S. (Philozxene) multispina (Sandberger). This speci- men is also from the Paffrath beds near Cologne and bears implantation scars similar to those de- scribed above on S. (Straparollus) laevis (Archiac and Verneuil). This specimen differs primarily from those of that species in being so high spired that it is considered trochiform. However, in view of the extremes in shape found in other species which im- plant, such as S. (EFuomphalus) hoffmani n. sp., it is conceivable that this specimen may be part of a population of S. (Straparollus) laevis. In addition, study of a species of Straparollus from the Early Devonian of Michigan (Linsley, 1968, p. 373-376) suggests that height of spire may be an .exceedingly variable character. The implantation scars are positioned below the periphery and rather low on the outer whorl face. The implanted foreign matter is placed at a position relative to the suture so that each successive whorl impinges below the attached foreign matter on the preceding whorl. Thus on both the body and the penultimate whorls impressions can be seen on the upper whorl face where shell growth had accom- modated the implanted foreign matter of the pre- ceding whorl. As the shell completes the next volution, subsequent growth will provide a second attachment site, one on each of two successive whorls. Another feature of this specimen is the notable regularity of the implantation sears. In general, the size of the scars and thus the inferred size of the implanted fragments increases in proportion to increase in whorl size. The distance between the centers of these scars also increases with marked regularity. Finally, this specimen shows implanta- tion of shell material at an earlier growth stage than do the planispirally coiled individuals of S. (Straparollus) laevis. In the specimen, the final three whorls all show attachment sears. Numbered specimen. - Hypotype: USNM 638255. Straparollus (Straparollus) sp. Plate 5, figure 20 Discussion. - A single external mold of a frag- ment showing two whorls was collected by Dr. Harold B. Rollins, University of Pittsburgh, from the "Cardiff Shale Member" of the Marcellus Shale, Hamilton Group, 3 miles south of Peterboro, N.Y. The preserved part is low trochiform and has a well- rounded whorl profile. The specimen is small and may be immature. It is too incomplete to name for- mally, but the depth of the sutures, which accentuate the roundness of the whorl section, mark it as dis- tinct. A bryozoan fragment is attached at the periphery of the upper whorl, and this fragment is also incor- porated into the lower preserved whorl. There are at least two other fragments closely spaced on the up- per whorl in the same position, and several nfay be seen at the periphery of the lower whorl. Numbered specimen. - Hypotype: USNM 188652. Straparollus (Straparollus) mortoni Linsley and Yochelson n. sp. Plate 6, figures 1-4 Description. - Medium-sized extremely low spired gastropods with rounded elliptical whorl profile, deep sutures, and a wide umbilicus. Nuclear whorls poorly known, apparently simple and dextral. Whorl profile of early growth stages virtually circular. Su- tures distinct and deep. Whorl profile becoming increasingly elliptical in maturity with long axis of ellipse nearly at right angles to axis of coiling. Shell height from essentially planispiral to low spired, the body whorl attaching below the periphery in adult forms. Umbilicus poorly known, but wide. Growth lines gently prosocline on upper whorl face, swing- ing to orthocline on outer whorl face and back to gently prosocline on base. Attachment sears on or below periphery of whorl, relatively large and evenly spaced. Shell unknown. Discussion. -This species is known from two external molds. On each of these molds is a badly preserved mold at the site of an attachment scar, which suggests that the attached fragment was also molluscan. The shape of these molds is not good enough for positive identification but suggests frag- ments of gastropod shells. This species most closely resembles Straparollus (Straparollus) laevis from Germany in that it is low spired and has evenly spaced attachment scars, whereas all other North American species show great variance and general irregularity in this fea- ture. S. (S.) mortoni also resembles the German carrier shells in the positioning of the implanted material as well as in the spacing. The two specimens of this species that are available for study suggest that the early whorls are planispiral, but that subsequently the whorls are depressed down from the original plane of coiling as the size increases, giving a low- spired adult form. The positioning of the implanted material varies in relation to the position of each successive whorl. In the early planispiral stages, the implanted material is placed at the whorl periphery, 10 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY but in the mature depressed whorls, implantation takes place lower on the outer whorl face. It differs from S. (S.) laevis in having larger attachment scars and in having a slightly more rapidly expand- ing shell, as a result of the elliptical mature whorl profile. Both S. (S.) cottrelli and S. (S.) cyclostomus are higher spired and have a rounded whorl profile. Numbered specimens. - Holotype: 183653; fig- ured paratype: 183654. Straparollus (Straparollus) cyclostomus (Hall) Plate 3, figures 6, 7, 12-18 Euomphalus cyclostomus Hall, 1858, p. 516, pl. 6, figs. 6a, b, c. Straparollus cyclostomus portlandensis Fenton and Fenton, 1924, p. 177-178, pl. 40, figs. 14, 15. Description. - Moderately large gastropods vary- ing from low spired to trochiform. Nucleus poorly known, but seemingly simple, dextral and discoidal; nuclear whorls continuous with first two neanic whorls, so that their upper surfaces lie in a hori- zontal plane. Whorl profile subcircular with only a suggestion of a slight angulation at the juncture of the upper and outer whorl faces; sutures distinct and moderately deep ; outer whorl face well rounded ; basal surface rounded in early growth stages but flattened slightly at maturity, though without any suggestion of a basal angulation. Widely phaner- omphalous; umbilical walls well arched and with distinct basal sutures. Shell planispiral in earlier stages, but gradually becoming increasingly trochi- form, with each succeeding whorl in contact at a lower point on the preceding whorl, though with a high degree of individual variation in this feature of ontogenetic change. Shell thick. Upper part of outer lip essentially orthocline with suggestion of a slight sinus midway between suture and periphery, varying widely below periphery from nearly orthocline to steeply prosocline and orthocline on the base, inductural deposits wanting. Growth lines closely spaced and rugose, with sporadic ce- mentation of shell debris; cementation scars, when present, tend to interfere with growth lines, causing them to be mildly prosocyrt on the outer whorl face. Shell moderately thick, with only slight thinning at parietal lip. Shell structure unknown. Discussion. - Twenty specimens of this species have been examined. Sixteen individuals formerly on display in an old museum exhibit are catalogued under USNM 9166, 183656, and 183657 "from five miles above Muscatine, Iowa." The collection was not labeled originally as to formation, though Cedar Valley is indicated on a later label. Four other indi- viduals collected by G. A. Cooper are catalogued 183655, 183658, and 183681 from a "quarry on Sweetland Creek, SEV, NW!4, SW, section 27, T. 7 N., R. 1 W., Muscatine County, Iowa" ; this lot is from the upper part of the Coralville Member of the Cedar Valley Limestone. Specimens in both lots are similar, and for convenience we have treated them as one population sample. Dr. William Furnish, Department of Geology, Uni- versity of Iowa, noted (written commun., Oct. 17, 1969) : Cooper's description does not agree precisely with our own (based on Illinois City Quad, 1953, 1:24,000). There are sev- eral ledges of Cedar Valley exposed in the east half of the NW 4, SW %, See. 27, T. 77 N., R. 1 W. The older collection is likely from exactly the same place, or almost certainly within a radius of a mile, east or west. The Cedar Valley exposures are rather limited "near Muscatine"; this spot is actually about four or five miles upstream. There has been some uncertainty about stratigraphic position, inasmuch as Stainbrook regarded the Coralville as being absent at Lin- wood and Buffalo nearby. Faunally, this ledge is certainly Coralville "or younger" according to Gilbert Klapper's analysis of the conodonts. There are no comparable faunas recovered from the type Coralville where the facies is ad- verse for conodonts. None of the available specimens of this species show attached foreign material in place (pl. 3, figs. 6, 16-18). Only four individuals out of 20 have sears or depressions on their shell which indicate that ob- jects were affixed at one time but subsequently have been broken off. On three of the specimens, only a single cementation sear is present (pl. 3, fig. 7). On the fourth (pl. 3, figs. 12-15), there are at least seven and perhaps as many as nine attachment sears on the body and penultimate whorls. This specimen, with a height of 15.2 mm and a width of 25.0 mm, is only slightly larger than that illustrated on plate 3, figure 6. It is somewhat different from the others in having a rugose appearance of the body whorl caused by rather coarsely developed growth lines. Had it not been from the same area and similar in height of spire to the specimen illustrated on plate 3, figure 6, it might well have been assigned to a sepa- rate species. In all, this small population is a most diverse group, showing a rather large variation of from % to / in height ratio. In more mature stages, variation may be seen both in the coarseness of growth lines and in implantation of debris. On all observable specimens, the two nuclear whorls and the first three juvenile whorls are quite smooth. Dur- ing later growth, there is a tendency for the whorl to become morls or less rugose in appearance because of irregularities of the growth lines. When implan- tation of foreign material does occur, it is only on the rugose area of the shell. The foreign matter is implanted at or very slightly above the periphery of the whorl. On the specimen with multiple cicatrices, SYSTEMATIC PALEONTOLOGY 11 the body sworl is positioned so that the suture occurs just at the base of the implantation zone. Although there may be a difference in size between the Cedar Valley specimens described above and the "Hackberry" forms described by Fenton and Fenton (1924), size alone is a highly subjective character and one that may be suspect, for it depends to a large degree on the amount of collecting and the abundance of the species. We prefer not to give any weight to it. As Fenton and Fenton discussed no other characters, and as their illustrations are similar to those of Hall, we have placed their variety in synon- ymy of this species. However, we have not examined Hall's type material nor that of the "variety" port- landicus (Fenton and Fenton, 1924, p. 177) from the "Hackberry," and our opinion is subject to sub- sequent confirmation. So far as we can determine, S. (S.) cyclostomus has not been formally described or illustrated by other workers. It has been listed as either Strapa- rollus or Euomphalus and as occurring in the Cedar Valley Limestone of Illinois (Savage, 1920, p. 180), in the Ouray Limestone of Utah (Hintze, 1913, p. 111), and in the Martin Limestone of Arizona (Ransome, 1916, p. 142), but none of these occur- rences have been documented, and we have not made any attempt to confirm them. S. (Straparollus) cycelostomus is readily distin- guished from S. (Straparollus) laevis and S. (Strap- arollus) incrustatus by its low spire. It is quite similar in general shape to S. (S.) cottrelli, but the absence of a circum ridge distinguishes it. Numbered specimens. - Hypotypes: USNM 9166 (unfigured), 183655 (figured), 183656 (figured), 183657 (figured), 183658 (figured), and 183681 (unfigured). Straparollus (Straparollus) cottrelli Linsley and Yochelson n. sp. Plate 4, figures 1-12 Description. - Low-spired broadly phanerompha- lous gastropods with rounded whorls. Nuclear whorls unknown. Sutures moderately deep. Whorl profile smooth, curved from suture to base following the outline of a wide downwardly inclined oval; some individuals with profile showing slight flattening so as to accentuate upper and outer whorl faces. Um- bilicus wide and deep; umbilical sutures sharp and deeply incised ; mature stage most commonly has low circumbilical ridge on basal whorl face. Apertural margin complete, circular in profile, lips showing no thickening; outer lip orthocline, with no reentrants or salients interrupting it; basal lip sharply proso- cline. Parietal inductura absent. Shell ornamented by fine, closely spaced growth lines. Foreign shell material, when present, cemented to periphery of several mature whorls. Shell thickness unknown. Discussion. - This species is known from a collec- tion of about 70 specimens from the basal 6 feet of the Rogers City Limestone (unit 1 of Ehlers and Radabaugh, 1938). The sediment was apparently de- posited as a supratidal dolomite, for the rock is a cryptocrystalline laminated dolomite with scattered mud-crack layers and scattered layers of shell hash (pl. 4, fig. 14). These shelly layers are interpreted as the result of storms which threw the shells into the supratidal zone where the dolomites were form- ing. As such, the specimens found in this unit are in a transported fossil assemblage (Fagerstrom, 1964), and from their present associations, little can be inferred of their ecology. In general, this species resembles S. (EFuomphalus) hoffmani n. sp., also from the Rogers City Lime- stone, in having a circumbilical ridge. S. (Strapa- rollus) cottrelli differs from that species primarily by having an obviously rounded whorl profile and in being lower spired. S. (Straparollus) cottrelli can be readily differentiated from S. (Straparollus) ?laevis by its smaller umbilicus, the presence of a circum bilical ridge, and a less rounded whorl profile. S. (Straparollus) cottrelli is like S. (Straparollus) cyclostomus in having a low spire height and a rounded whorl profile, but the cireumbilical ridge in this form readily distinguishes the two species. S. (Straparollus) cottrelli has a more rounded whorl profile and is much lower spired than S. (?WFuom- phalus) incrustatus. Like other species of Devonian carrier shells, S. (Straparollus) cottrelli shows considerable varia- tion. The circumbilical ridge is only slightly devel- oped in some individuals (pl. 4, fig. 4) and rarely is as prominent as in S. (EFuomphalus) hoff mani. A few specimens (pl. 4, fig. 6) have little if any foreign matter implanted in the shell, whereas others (pl. 4, figs. 1-3, 7) have an abundance of attached materials. Most specimens have a rounded whorl profile (pl. 4, figs. 11, 12) characteristic of the typi- cal subgenus. Several (pl. 4, figs. 2, 10) have devel- oped a faint angulation between the upper and outer whorl faces, thereby assuming an appearance similar to that of the subgenus EHuomphalus ; this flattening of the profile is not a result of postmortem crushing of the shell. One interesting aspect of this species is that many individuals have been preserved with the attached foreign matter intact, so that one can actually see what was cemented without having to try to infer it from the attachment sears. For the most part, the attached material consists of entire gastropod shells 12 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY of several sorts, but there is an occasional tentac- ulitid or broken shell fragment of undetermined origin. Judging from the molds and steinkerns, this species had a shell of moderate thickness. Units 2 and 3 of the Rogers City Limestone over- lying the beds that contain S. (Straparollus) cottrelli are 7 feet thick, but in contrast to unit 1, they mainly lack gastropods ; unit 2 is essentially unfossiliferous, and unit 3 carries only Atrypa in profusion. Only two euomphalids have been obtained from units 2 and 3. They are both incomplete but seem to be inter- mediate in height of spire between S. (Straparollus) cottrelli and S. (Euomphalus) hoff mani. The speci- men from unit 2 (USNM 183662, pl. 4, fig. 11) is sufficiently similar to S. (Straparollus) cottrelli to warrant its inclusion in this species. However, the specimen from unit 3 (USNM 183664, pl. 4, fig. 13) lacks the cireumbilical ridge and has a relatively narrow umbilicus which suggests that it is higher spired. It seems to lack an upper angulation, but it does have abundant attachment sears. Thus, the specimen has features that are essentially intermedi- ate between S. (Straparollus) cottrelli and S. (Euomphalus) hoffmani as well as an intermediate stratigraphic position. Because of the apparent in- termediacy of features combined with the paucity of material, we have only provisionally assigned this specimen to S. (Straparollus) cottrelli. Numbered specimens.-Holotype: USNM 183659; figured paratypes: USNM 183660, 183661, 183662, 183663, and 183679 and UMMP 22375. Subgenus Euomphalus J. Sowerby Straparollus (Euomphalus) hoffmani Linsley and Yochelson n. sp. Plate 5, figures 1-19 Description. - Relatively high spired, phanerom- phalous, moderately large euomphalaceans. Nucleus and early growth stages unknown. Suture distinct, of variable depth. Pleural angle 50° to 80°. Juvenile whorls moderately rounded. Whorl profile in mature stage roughly pentagonal ; upper whorl face flattened to gently arched, inclined 45° below horizontal, with a prominent shoulder at juncture of upper and outer whorl face; nearly vertical outer whorl face flat to gently arched, and joining base at an equally promi- nent angulation ; base flattened, inclined gently down- ward from %uter angulation to prominent cordlike cireumbilical ridge; at cireumbilical ridge, whorl profile turning steeply upward into moderately nar- row umbilicus; umbilical suture poorly known. Growth lines opisthocyrt on upper whorl face, bend- ing to orthocline on outer whorl face and continuing orthocline over basal part of whorl and into the umbilicus. Parietal inductura absent, revolving ornament consisting only of cireumbilical cord and angulations bounding outer whorl face; transverse ornament of fine closely spaced growth lines. Shell moderately thick ; its structure unknown. Discussion. - This species is by far the largest of all the Devonian carrier shells. Its strong circum bili- cal cord, angulated profile, and high spire make it distinctive. It is also the most consistent implanter of foreign matter among all the Devonian species con- sidered in this paper. All 52 specimens collected show attachment scars, whereas in most of the other "pop- ulations," attachment is rare. S. (EFuomphalus) hoff mani is also noted for implanting far more for- eign matter per individual than the other species. The foreign matter has been separated from the molds of all specimens of this species, and knowledge of its nature is by inference from examination of the cicatrices. The attachment sears of typical ma- ture specimens are exceptionally large and crowded ; although occasionally an entire volution may exist with no attachments having been made (pl. 5, fig. 9), this is rare. There appears to be a fairly consistent relation- ship between spire height and the time of first im- plantation of shell particles. In general, the higher spired shells (those with a smaller pleural angle) implanted foreign matter earlier in life than the low- spired shells. For example, the high-spired shell shown on plate 5, figures 15, 18, and 19, has implan- tation scars at the beginning of the third volution, whereas the low-spired specimen shown in figures 4, 8, and 12 has no scars until the beginning of the fourth volution. Counting whorls in individuals of this species is most difficult, for in every specimen the nuclear whorls have been broken off, frequently in the same relative position, adding to the disreputable overall appearance of the shell. Septation or apical plugging appears to have been relatively common in these shells, for frequently the steinkern terminates abruptly apicad with a rounded, smooth surface. This species is known from 52 specimens from the upper 58 feet of the Rogers City Limestone (units 4-6 of Ehlers and Radabaugh, 1938). Most of the specimens were collected from the shore of Lake Huron 0.6 mile north of Rockport quarry, Alpena County, Mich. Others were obtained from rubble on the Lake Huron beach of False Presque Isle, just north of Knight's Bay, or from rubble of the Calcite quarry at Rogers City, Mich. Numbered specimens. - Holotype: UMMP 22369; figured paratypes: UMMP 22370, 22372, 22374, SYSTEMATIC PALEONTOLOGY 13 57888, and 57889 and USNM 102938, 183665, 183666, and 183667. Straparollus (Euomphalus) winnipegosis Linsley and Yochelson n. sp. Plate 6, figures 19, 21 Description.-Trochiform gastropods with a mod- erately high spire and a deep umbilicus. Nuclear whorls unknown. Pleural angle about 90°. Suture moderately deep. Whorl profile of immature whorl circular in cross section, gradually developing an upper shoulder which becomes pronounced in more mature whorls; upper whorl face flattened and de- pressed about 30° below horizontal, but in more ma- ture stage concave with flat band near shoulder; outer whorl face rounded in neanic whorls, flattened in mature whorls; whorl face curving smoothly onto base without angulation. Base poorly known, appar- ently without cireumbilical ridge. Umbilicus poorly known, possibly deep. Growth lines with shallow sinus on both upper and outer whorl faces; outer lip gently opisthocyrt on upper whorl face, rather sharply prosocyrt over shoulder and once again gently opisthocyrt on outer whorl face and continu- ing in orthocline manner onto base. Ornament con- sisting only of fine growth lines. Shell unknown, apparently of moderate thickness. Entire outer whorl face serving as area for implantation of foreign matter. Discussion. -This species is known from the ex- ternal mold of a single specimen collected from the Winnipegosis Formation. S. (Wuomphalus) winni- pegosis resembles S. (Euomphalus) hoff mani n. sp. from the Rogers City Limestone in overall shape and also shows abundant attachment scars on the outer whorl face. It has a slightly lower spire than that species, shows no evidence of a prominent lower angulation, and has a concave upper whorl face. Although individually these differences are slight, collectively they provide a firm basis for the estab- lishment of a new species. The gastropod fauna of the Winnipegosis Forma- tion is fairly well known through the work of Whit- eaves (1891la,b; 1892) and more recently McCam- mon (1960). Even if one ignores the presence of attachment scars, the profile of this species is dis- tinct from other euomphalids described from the region. The locality is in a quarry in Lsd. 4, See. 21, Twp. 24, Range 10W PM, about one-fourth mile west of the Narrows, Lake Manitoba. It is stop 18 of the guidebook prepared by McCabe (1967), and it is approximately a mile west of locality 1 of McCam- mon (1960, p. 10). Numbered specimen. - Holotype: USNM 183668. 506-182 O - 73 - 3 Straparollus (?Euomphalus) incrustatus Linsley and Yochelson n. sp. Plate 6, figures 5-18, 20 Description. -Trochiform gastropods with a rounded to subelliptical whorl profile and a deep umbilicus. Nucleus unknown. Whorl profile varying from subcircular in juvenile stage, through subangu- lar to slightly pendant at maturity; suture deep; upper whorl face moderately well arched between suture and outer whorl face; slope of arched outer whorl face declining with age and having periphery low on whorl; slight basal angulation ; base flattened for most of its width but proceeding into umbilicus with strong curvature. Umbilicus moderately wide and deep; umbilical sutures very deep. Parietal in- ductura absent. Ornamentation consisting of closely spaced faint growth lines, orthocline on upper whorl surface, shallowly opisthocyrt along outer whorl face and orthocline on base. Attached foreign material or sears of attachment variably positioned on outer whorl face and closely but irregularly spaced and seemingly absent on early whorls. Shell moderately thick; its structure unknown. Discussion. -This species is known from about 19 silicified specimens collected by M. H. Staatz in 1954 from the Middle Devonian of Utah (USGS loc. 5829-SD). Much of the material is fragmentary, and several specimens are crushed. In general, the gradual change from the moderately higher spired early stage to the broader mature body whorl is comparable to that of the genus Omphalotrochus; the shape is best described as crudely pagodiform. This ontogenetic change in the shape of the whorl profile is regular, but because most specimens do not preserve the various growth stages, the first impres- sion is of great diversity and irregularity. The holo- type, slightly crushed, measures 17.0 mm in width and 12.5 mm in height. All specimens save one are closely comparable to the holotype. This single juvenile (paratype 183677, pl. 6, figs. 5-7), differs from the rest of the sample in having a pendant whorl profile with the outer whorl face quite flattened and inclined at about a 45° angle to the axis of coiling. Other specimens of about the same size have already formed a whorl wider than high. This species is also unusual in that all specimens have many attachment sears. Some still show foreign shell matter attached to the shell. The one identifi- able piece of attached foreign matter is a complete immature specimen of S. (?WFuomphalus) incrus- tatus. Two other attached pieces may be fragments of gastropod shells, though the identification is in doubt because of their incompleteness. The shell in 14 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY areas of attachment is exceedingly thin, and perhaps was so thin that it could not silicify. As a conse- quence, the shells are fragile and therefore especially susceptible to crushing. S. (?2Euomphalus) incrustatus is higher spired than S. (Straparollus) cottrelli and S. (Straparol- lus) cyclostomus, and it has less rounded whorls than either of these. The flattened outer whorl face distinguishes it from S. (Straparollus) laevis. S. (?Huomphalus) incrustatus resembles S. (Euom- phalus) hoff mani in spire height; the latter species does not undergo the ontogenetic change of spire height and consistently has an angulation between the upper and outer whorl faces. The lack of a cireumbilical ridge at all growth stages readily dis- tinguishes S. (?.) incrustatus from S. (E.) hof- mani. The oval to pendant whorl profile and the absence of a concave upper whorl face distinguish this species from S. (F.) winnipegosis. Numbered specimens.-Holotype: USNM 183669; figured paratypes: USNM 183670-183677 ; unfig- ured paratypes: USNM 183678 (10 specimens). STRATIGRAPHIC DISTRIBUTION German species discussed in this paper are from beds best characterized by the Givetian brachiopod Stringocephalus. The association of Devonian car- rier shells with Stringocephalus or with other ele- ments of the stringocephalid fauna is maintained in several of the occurrences in North America. This suggests that it is worth exploring whether the in- crusting habit might be of some stratigraphic sig- nificance. The occurrence of species discussed in this paper is shown in figure 1. The one undisputed association of a carrier shell with Stringocephalus in North America is that of Straparollus (Euomphalus) winnipegosis, n. sp., from the Winnipegosis Formation of Manitoba, where it occurs with Stringocephalus cf. S. sapiens Crickmay. Farther southwest, S. (?Wuomphalus) incrustatus, n. sp., was collected from low in the upper part of the Engelmann Formation of Utah ; it was originally listed as Straparollus cf. S. ophirensis Hall and Whitfield, a Mississippian form. It occurs with Athyris cf. A. angelicoides Merriam (Staatz and Carr, 1964, p. 52). Fossils in the Engelmann are sparce and rarely well preserved, but lower in the formation, poorly preserved brachiopods were identi- fied by C. W. Merriam as "probably Stringocephalus sp." (Staatz and Carr, 1964, p. 52). A post-Givetian age is indicated for the part of the Engelmann that yielded this species of Straparollus. Poole and others (1967, p. 887) give a general correlation of this for- mation. Although Stringocephalus has not been identified in the Rogers City Limestone of northeastern Michi- gan, other elements of the North America Givetian Stringocephalus fauna do occur. Straparollus (Euom- phalus) hoff mani, n. sp., occurs in the upper part of the Rogers City Limestone with a diverse fauna in- cluding such stratigraphically significant forms as Atrypa arctica, Subrensselandia sp., Liromytilus at- tenuatus, Omphalocirrus sp., and Buechelia tyrrellui. Straparollus (Straparollus) cottrelli, n. sp., occurs in the lower part of the Rogers City, where the fauna is more restricted but does include Carinatina dysmorphostrota, generally considered a member of the Givetian equivalent fauna (Ehlers and Kessling, 1970, p. 29). The remaining species cannot be readily correlated with the Stringocephalus fauna. Presumably this fauna was an incursion from the north, and in the Eastern United States the incursion was of brief duration. This is best seen in the Michigan section, where the Traverse Group is readily correlated with the New York section. In Michigan, S. (Straparol- lus) mortoni from the "Gravel Point Formation" is clearly younger than the Stringocephalus fauna of the Rogers City; it is impossible to determine whether this species is younger than or equivalent to the Stringocephalus fauna which occurs in Mani- toba. In New York, the Marcellus Shale is considered to be Eifelian (Cooper and Phelan, 1966, p. 8). Straparollus (Straparollus) sp. occurs in the "Car- diff Shale Member," the uppermost member of the formation. Although we have followed Cooper and Phelan in indicating a break between the Marcellus and the overlying Skaneateles, this may not be of any great time significance; this species might be in beds equivalent to the Rogers City. The Ludlowville species S. (?Serpulospira) eboracensis, in spite of the uncertainty that surrounds its precise occur- rence, is definitely from beds younger than those on this continent considered to contain Stringocephalus. Most species noted occur within the Cazenovian and Tioughniogan Stages of American usage. How- ever, S. (Straparollus) cyclostomus (Hall) from the "Coralville Member" of the Cedar Valley Limestone in Iowa definitely occurs in younger beds, considered to be Taghanican in age (Cooper and others, 1942; Cooper and Phelan, 1966, p. 9). Thus, in North Amer- ica, Devonian euomphalids that have the incrusting habit are widely distributed stratigraphically within the Middle Devonian. The Iowa occurrence may be in beds of earliest Late Devonian age (Johnson, 1970, p. 2080). The western species S. (?Fuomphalus) in- crustatus is from beds of Frasnian Age. It is difficult to make an exact correlation of the POSITIONING OF SHELL DURING IMPLANTATION 15 | Series | FIGURE 1. - Stratigraphic occurrence of incrusting euompha- lids, mainly from Cooper and Phelan (1966). Utah column from Poole and others (1967) ; column for German material from Jux (1964, and written commun., 1972) and Erben and Zagora (1967). Intercontinental correlations from Johnson (1970). Occurrence of species indicated by num- bers: 1, Straparollus (?Euomphalus) incrustatus, n. sp.; 2, S. (Euomphalus) winnipegosis, n. sp.; 3, S. (Strapa- German beds that have produced incrusting speci- mens. The similarity between the Rogers City fauna and that of the Biicheler beds is impressive, but the best available correlations suggest that Stringoce- phalus in the German section might be younger than in Michigan. We conclude that identification of the incrusting habit in a HFuomphalus could be supporting evidence for assigning a Middle to early Late Devonian age to a fauna. In the absence of any other faunal ele- ments, however, assumption of a Middle Devonian age would be hazardous. Even though we know of no Paleozoic occurrences other than those described herein and scattered Ordovician and Silurian forms Seriesf Stage Western Utah Southern Manitoba Eastern lowa Northern Michigan Central New York | Western Germany | Stage Nud XC V7\ % Nac IG \| Refrather < Hgfiauer yy a X % Hackberry " Schichten <2t i ilson ~ he f = c z Goshoot C $ T\Y\\ Wiscoy = § 5 | & & \ XQ Addo: Oberer 2 | § o ~ 1 $ E XExcxd Naples & 5 eon dt Plattenkalk Co Me 5 & Sweetland Creek ‘ o w a ~ 3% ~ -| & a- N \ > ~ S S & £ Lats. < 4 in-Parti S $22 fz" \\\\‘§§\ \1\ ax cs,. awex Geneseo Hornstein-Partie c P yx > é z < # Fx 2 & md z < i 3 & Gravel, Four Mile Dam 3 3 Point "3 Alpena 3 o -~ Newton Creek fringe, oa Genshaw Skaneateles ( ; Schichten Ferron Point Rockport Quarry] g Bell E 2 x 2 € x | Unter fo 2 s \ ~ Honseler u N a o : Gx XXL S Rogers 5 K i ba é 4 x & Elm Point x \\\i\\\\ ~ City 4 ‘\ Schichten a = (e - - ~> x % mf S 5 <3 hs \\\ so Dundee Marcellus 7 Brandenberg & 3 ho \ \ C4 Schichten & C | LL yx G. \\ rollus) cyclostomus (Hall) ; 4, S. (Straparollus) cottrelli, n. sp.; 5, S. (Euomphalus) hofmani, n. sp.; 6, S. (Strapa- rollus) mortoni, n. sp.; 7, S. (Straparollus) sp.; 8, S. (2Serpulospira) eboracensis (Hall); 9, S. (Straparollus) laevis (Archiac and Verneuil); 10, S. (Straparollus) ?laevis (Archiac. and Verneuil); 11, S. (Serpulospira) centrifuga (F. A. Roemer). which have not been carefully studied, this may be simply a function of incomplete collection or poor observation. The incrusting habit clearly has evolved independently several times and cannot be an infal- lible stratigraphic indicator. 5 POSITIONING OF SHELL DURING IMPLANTATION In the modern xenophorids, the positioning of in- crusted materials is consistent, with the exception of Tugurium (Tugurium) lamberti. The latter is said by Tryon (1886, p. 162) to implant foreign matter at the suture, whereas all other xenophorids implant their foreign matter at the periphery. 16 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY In the Devonian carrier shells from Germany there is some variation in the point of implantation of foreign material. This variation seems to correlate well with height of spire. In S. (Straparollus) ?laevis, a low-spired almost discoidal form (p. 9), the implantation scars are at the periphery of the shell. In S. (Straparollus) laevis, a higher spired form, the cicatrices are distinctly below the pe- riphery. In each, the incrusted material does not interfere with the growth and positioning of the succeeding whorl. This next whorl abuts just below the implanted material of the preceding whorl; the implanted material will sometimes be cemented to both whorls. In Straparollus (Serpulospira) centrifuga, the dis- junet nature of the whorls obviates the considera- tions on placement mentioned above. Yet the positioning of the incrusting material on the periph- ery is the same pattern as in S. (Straparollus) ?laevis, a form which has a comparable low spire height. The open coiling of this Serpulospira demonstrates that the positioning of incrusted matter in this group of German snails is not dictated completely by the geometry of shell coiling. It is more likely that the positioning of the incrusted matter is determined by the relationship of the shell to the soft parts when implantation takes place. This might be determined either by the amount of regulatory detorsion of the shell, or by its attitude when resting on the sub- strate. In a gastropod with a low-spired shell like S. (Straparollus) ?laevis, the shell would be balanced on the foot with almost a full 180° torsion (Naef, 1911) (fig. 2A). In the normal carrying position of this shell, its periphery is directly over the center of the head. However in a gastropod with a higher spired shell like S. (S.) laevis, both regulatory de- torsion and inclination must occur for the shell to be balanced over the visceral hump of the organism (fig. 2B). This brings the periphery around in the direction of the spire (the animal's right), and a point below the shell periphery will be over the cen- ter of the head. This is the normal carrying position for most modern gastropod shells, and if the process of implantation of foreign objects is related to the normal carrying position, then this could explain why higher spired shells may have debris implanted lower on the outer lip than low-spired shells. Though the explanation presented above fulfills the mechanical requirements to explain variation in position of implantation scars on the German shells, we believe it to be inadequate. The cementation process in Xenophora conchyliophora takes 10 to 12 FIGURE 2. - Reconstruction of euomphalids as mobile animals. A, Low-spired form represented by Straparollus (Strapa- rollus) ?laevis, showing torsion with shell essentially sym- metrical on the foot. B, Higher spired form represented by S. (Straparollus) laevis, showing regulatory detorsion and inclination of shell relative to foot. hours (Shank, 1969, p. 6). Although the fragments cemented by S. (Straparollus) laevis were smaller than those used by modern carrier shells, it is doubt- ful that a sheet of calcium carbonate of sufficient strength to bind the foreign particle could be se- creted in any appreciably shorter time. It seems most unlikely that S. (Straparollus) laevis could have held its shell motionless in the normal carrying position for the several hours required for this pro- cess. Our interpretation is that foreign matter was implanted when the shell rested on the bottom (fig. 3). If a euomphalid with an implanting habit was sedentary, and if the length of time involved to im- bed foreign matter firmly in the shell was commen- surate with -that of the modern xenophorids, then during implantation the shell must have been rest- ing, umbilicus down, on the substrate. In low-spired shells such as S. (S.) ?laevis, foreign matter placed on the sea floor and leaned against the shell would touch it at the periphery (fig. 3A). In high-spired shells such as S. (S.) laevis, the spire would slant to one side, and foreign matter similarly placed would strike the shell below the periphery (fig. 3B). With the exception of S. (Straparollus) mortoni, the Devonian carrier shells of North America, un- like their German counterparts, do not show such striking differences in the region of incrustation. Essentially, they all cement the foreign matter some- where near, but not necessarily at, the periphery. Straparollus (Euomphalus) hoffmani and S. (E.) DISTRIBUTION AND NATURE OF IMPLANTED MATERIAL 37 FIGURE 3. - Reconstruction of euomphalids as sessile animals. A, Low-spired form in process of implanting a fragment at periphery. B, Higher spired form engaged in similar activity with the fragment lower on the whorl. winnipegosis have a flattened outer whorl face, and all implantation takes place within this area. We suggest that this flattened area provided a relatively broad zone, any part of which would have been a stable area against which to lean foreign shell frag- ments. S. (?Straparollus) incrustatus is rather high spired, and the implantation sears indicate that for- eign matter was attached randomly on the outer whorl surface, some of it high and some of it low. No operculum is shown in the reconstruction of soft parts in figure 3. In living Xenophora, the oper- culum is far back on the foot so that part of it is seen extending upward beyond the metapodium. In most living gastropods the operculum is positioned more anteriorward, and one would assume that this position would be similar in earlier forms. In such a location, it would be hidden by the sole in the recon- struction. However, in spite of the lack of any proof of an operculum in the fossil record, we believe that such a structure would likely have been present. For a sedentary form, an operculum would be particu- larly useful, if only to close the aperture in turbid water. Few opercula are known for the Euompha- lacea, but on the basis of scattered observations (Yochelson and Linsley, 1972), we would suspect that a multispiral operculum would be the most rea- sonable form to fit the aperture. The complex twist- ings required to affix foreign particles to the shell would make it unlikely that such an operculum would be calcified. DISTRIBUTION AND NATURE OF IMPLANTED MATERIAL As frequently stated in the literature, the modern carrier shell is selective in its choice of implanted material. For example, Sohl (1960, p. 96) noted that specimens of Xenophora "from the Ripley for- mation on Coon Creek, Tennessee, preferred bivalves of the genus Caesticorbula." Observations of museum collections of Xenophora and especially X. pallidula, combined with life studies of X. neozelanica, suggest most strongly that although there often is selection of material, it is based only on size of particles avail- able. Except for this criterion, the carrier shells are not selective relative to composition or shape of ma- terials. The size of the foreign material selected increases as the size of the organism increases. Con- sequently, Xenophora may change from one kind of material or a particular species to another during growth. (See pl. 1.) In specimens of S. (Straparollus) cottrelli, n. sp., S. (Straparollus) sp., and S. (?FHuomphalus) in- crustatus, n. sp., foreign matter is preserved intact on the shell. S. (Straparollus) cottrelli is the best known species in this regard because of an abun- dance of specimens with implanted material still intact. The foreign material consists largely of small gastropods, frequently immature members of this species (pl. 4, figs. 2, 3), bellerophontids (pl. 4, fig. 5), and other low-spired gastropods (pl. 4, fig. 1) ; occasionally even high-spired murchisonids are ce- mented to the shell. Only rarely is material other than gastropods implanted. The available specimens of Straparollus (?Fuom- phalus) incrustatus include two examples which have implanted material in place, and again the for- eign matter is composed of small gastropod shells. The single specimen of S. (Straparollus) sp. has one fragment of a fenestellid bryozoan intact (pl. 5, fig. 20). The single specimen of S. (?Serpulospira) eboracensis (Hall) (pl. 3, fig. 20) is scarred with im- pressions of fragmentary brachiopod valves, mostly of Atrypa sp. (G. A. Cooper, oral commun., 1970). In the German species, and in S. (Straparollus) mortoni, S. (Straparollus) cycelostomus, and S. (Euomphalus) winnipegosis, there is no way to de- termine what materials were originally implanted. Cicatrices are distinct, and one would judge that foreign material was firmly implanted. However, Linsley has noted that many individuals of X. neo- zelanica have lost some or even most of their im- 18 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY planted material during life. The loss of foreign fragments cannot be attributed solely to diagenetic effects. In S. (Euomphalus) hoff mani, the cicatrices are distinct, and it is possible in many specimens to de- termine what had been implanted even though no material is left. It is apparent that crinoid columnals (pl. 5, figs. 15, 18), brachiopods (pl. 5, figs. 5, 6), and gastropods (pl. 5, fig. 17) (either fragmented or entire) were used. We estimate that the material on the shell is in roughly the same proportion as the fragments in the rock matrix. In the Rogers City collection, calcite fossils such as crinoid stems and brachiopods have been pre- served. Gastropod shells and some implanted frag- ments have been dissolved and thus are known only from external molds or natural casts of secondary calcite. Presumably the euomphalid shell was arago- nite which has been differentially dissolved. One result of this is that the natural molds and casts from the Rogers City show selectivity in apparent preservation of implanted material. S. (Straparol- lus) cottrelli implanted primarily aragonite gastro- pod shells. In these, both the incrusted shell and its incrustations have dissolved, and the molds show the animal in its full incrusted state. S. hoff mani used calcite brachiopods and crinoids for its implanted material. Differential solution left these embedded in the matrix while the aragonite gastro- pod shell was dissolved from under them. As a result, casts of specimens of S. (F.) hoff mani all appear to have had the foreign material broken off ; in fact, most of it is still present in the matrix surrounding the molds. We see no difference in the implantation of calcite or aragonitic material. It is well known that the modern Xenophora is capable of implanting materials that have a wide variety of chemical com- positions, including calcite and aragonite shells, phosphate nodules, pebbles of varying mineralogy, and even wood and coal. One other aspect of implantation is worth noting. The three German species that have been discussed in this paper are similar in that the implantation scars and the implanted material have a marked regularity in size and in spacing. The sears are all small compared with those of American forms and show gradual but regular increase in size, roughly proportional to the increasing size of the whorls. In addition, the separation between the centers of the scars increases, approximately in a logarithmic man- ner. Those two traits, combined with the uniform positioning of the sears on the whorl, create an over- all appearance of marked regularity. In contrast, the majority of the North Ameri- can carrier shells are a disreputable-looking lot. We cannot detect any trends in size or spacing of implantation sears. The one exception among the North American forms is S. (Straparollus) mortoni. In this species, the implantation scars increase reg- ularly in size, but they are larger than those of the German forms. The scars are so large that in some areas of the shell they are in contact. FUNCTIONAL SIGNIFICANCE OF IMPLANTED MATERIAL Some earlier literature suggested that the im- planted material serves to thicken and strengthen the thin shell of Xenophora. This view of functional morphology is false. The convergence in implanta- tion habit is reinforced by the contrast of the trans- lucent shell of most of the Xenophoridae with the thick shell of the Devonian forms. This thicker shell allowed the implanted material to be placed very deep into the shell without interfering with the in- ternal profile of the whorl as it does in Xenophora. However, the implanted material in these fossils actually resulted in a relative weakening of the shell at the attachment points; the foreign material did not strengthen the shell. The thin shell of modern Xenophora may be viewed as a more efficient means of implanting material. The process of secretion at the mantle edge is faster in the modern forms than in the Devonian species. In Xenophora, the implanted materials serve at least two functions, that of stilts to support the base of the shell above the substrate and that of camou- flage. In the Devonian carrier shells, the implanted materials seem to have functioned solely as camou- flage. This role would be perfectly consistent with the assumed ecology of these gastropods, namely as predominantly or entirely sedentary organisms. The protection provided by the incrusting habit as it was evolved by the various straparollids would seem to be slightly different from that of the modern xenophorids. Even in the most completely covered individuals of S. (WFuomphalus) hoff mani, only 60-70 percent of the shell is hidden by the incrusting ma- terial, whereas in some species of Xenophora the coverage approaches 100 percent. In the less covered euomphalids, the incrustations do little more than slightly interrupt the smooth outline of the shell. In the Devonian fauna, the most probable preda- tors on the Devonian gastropods were cephalopods, though direct evidence of predation is lacking. It seems doubtful that cephalopods of the Middle De- vonian had eyes as well developed as those of the modern coleoids and octopods; they probably had eyes that were no better developed than and prob- ably not as good as those of the living Nautilus. We would suggest that the cephalopods of the Devonian EVOLUTIONARY GROUPS OF could have been more dependent on tactile stimuli for their food search than they were on visual stim- uli. If this were true, even a few broken shells attached to the gastropod shell may have had at least limited positive value against the selection pressures exerted by these predators. PRESENCE AND ABSENCE OF IMPLANTED MATERIALS One of the most puzzling aspects of the Devonian carrier shells is the apparent inconsistency in the habit of implanting material. Within some of the assumed life populations, not all members implant foreign material. Of the 11 species of Devonian car- rier shells discussed in the systematic section of this paper, seven are known only from single or very few specimens, and we have assemblages of only four of them. From the literature we can infer something about the variation of this feature in two other species. For the type species of Kayser's genus Philozene, S. (Straparollus) laevis (Archiac and Verneuil), the Paffrath population includes specimens with and without attachment sears. As noted, the type speci- men for S. (S.) laevis does not show attachment sears, yet this is the feature on which Kayser based his new genus. Knight stated (1941, p. 242) that attachment scars "are present on other probably conspecific specimens." Thus in the Paffrath, there are obviously some specimens of S. (S.) laevis (and probably S. (S.) ?laevis) that did implant foreign matter and some that did not. The same may be said for S. (Serpulospira) centrifuga (F. A. Roemer). The type specimen shows no sign of attachment scars (Knight, 1941, p. 316), but the specimen figured in this paper leaves no doubt that scars are present on at least one specimen from the Paffrath. Among the four North American species in which relatively large samples are available for study, we find that in S. (Straparollus) cycelostomus, four of the 20 specimens show cicatrices. In S. (Straparol- lus) cottrelli, about 40 of the 70 specimens show attachment scars. All 20 specimens of S. (Strapa- rollus) incrustatus and all 52 specimens of S. (Fuom- phalus) hoff mani have abundant attachment sears. The presence or absence of attached material is related to the age of the specimens, for this habit is primarily an adult character. That alone cannot ex- plain all the variations. In all populations studied where implantation may be present, there are large individuals that have no cicatrices. We postulate that, at least intitially, the presence of this habit was dependent upon some triggering mechanism in the environment that was only intermittently pres- ent. DEVONIAN CARRIER SHELLS 19 According to C. M. Yonge (oral commun., 1970), there is an analog to this environmental factor in the modern shipworm Teredo. If debris of finely comminuted wood is allowed to pile up around the entrance to its burrow, Teredo will secrete a small calcareous tube up through the "sawdust" to keep a clear channel available into its burrow. If, how- ever, wave action is sufficient to sweep away the debris, then no tube is constructed. Thus the pres- ence or absence of this apertural tube is dependent on conditions in the environment. A similar analog is in the pelecypod Amphidesma australe Gray (Roger Grace, oral commun., 1971). The immature members of this species, 3-15 mm long, that live in a current-swept area of coarse sand secrete a single byssal thread to provide attachment. Similar-sized specimens of the same species that live in quiet water do not secrete a byssal thread. THE STATUS OF PHILOXENE We feel that the presence or absence of attached foreign material in the Devonian carrier shells must be dependent upon an unknown external stimulus, as suggested in the section above. This character is not consistent within a population in some of the species examined. Accordingly, we conclude that the habit of attaching foreign matter to the shell is not an adequate criterion for differentiation of Paleozoic gastropods at any taxonomic level. Consequently, we here transfer Fuomphalus laevis to the typical subgenus of Straparollus so that Phil- oxzxene Kayser is placed in synonymy. The various other species that have been assigned to Philozene should be transferred to the several subgenera of Straparollus, depending on their whorl profile and overall shape. Because the implanting habit is not necessarily constant, some of these species may be placed in the synonymy of nonimplanting species otherwise identical in shape. Currently Philozene is treated as a subgenus under Straparollus (Knight, Batten, and Yochelson, 1960, p. I-198). EVOLUTIONARY GROUPS OF DEVONIAN CARRIER SHELLS Two distinctive assemblages can be seen within the Devonian species of carrier shells. The first is based on the German forms from the Paffrath beds, and the second is represented by species in the Rogers City and Winnipegosis Formations. Other species may have no relationship to either of these groups. The three German species S. (Straparollus) laevis, S. (Straparollus) and S. (Serpulospira) centrifuga are all similar in that they have narrow whorls ; by this it is meant that the generating curve 20 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY expands very slowly as it is translated along the axis of the cone (Raup, 1966). Further, attachment of foreign matter is an occasional event, most of the individuals of each of the three species not implant- ing foreign matter. Finally, all the individuals that implant are characterized by having small regularly spaced attachment sears that consistently are on the periphery of the shell. Collectively, these character- istics suggest that the species have a common an- cestry. Straparollus (Straparollus) mortoni from the "Gravel Point Formation" of northern Michigan resembles the German forms in having a low rate of whorl expansion, in having the implanted material positioned consistently at the periphery, and in hav- ing a regular spacing of the implanted material. As this species is known from only two specimens, it is not possible to comment on the frequency of the im- planting habit. However, there is enough similarity between this species and the German forms to sug- gest that they are probably related. There is an obvious difference in overall shape between this planispiral form and the low-spired S. (Straparol- lus) laevis, but the differences are no greater than between S. (S.) laevis and the high-spired S. (S.) ?laevis or the open-coiled S. (Serpulospira) centrif- uga. Specimens of some species in the typical sub- genus of Straparollus have a great deal of individual variation in general form (Linsley, 1968, p. 373-376). Straparollus (Straparollus) cyclostomus from the Cedar Valley Limestone of Iowa has a whorl expan- sion rate similar to that of the first group. It also shows considerable individual variation in height of spire and in presence or absence of cicatrices. It is different in having fewer implantations per indi- vidual. On the one specimen which has more than one implantation, the cicatrices are irregular in spacing and position. This species is so far removed temporally from any of the other Devonian carrier shells that any suggestions of relationship are most tentative. The sécond and better documented group is ex- clusively North American and includes S. (Strapa- rollus) cottrelli, S. (Euomphalus) hoffmani, and S. (Exuomphalus) winnipegosis. The oldest known mem- ber of this lineage is S. (Straparollus) cottrelli from the basal 6 feet of the Rogers City Limestone of Michigan. This species differs from all those of the first group in having wider whorls; by this it is meant that the generating curve expands more rap- idly as it moves along the axis of the cone relative to the first group. It is also distinguishable in having a weak to moderately strong cireumbilical ridge. Implantation occurs more frequently within a popu- lation of shells, about 50 percent of the popula- tion adopting the habit. The implanted material of this species is not regularly placed on the periphery, and there is considerable variation in spacing and size of the implanted material. Straparollus (Euomphalus) hoffmani occurs in the upper two-thirds of the Rogers City Limestone. It is separated from S. (Straparollus) cottreli by less than 10 feet of sparsely fossiliferous dolomites and limestones. The only specimens collected from this interval are incomplete, but in some ways they are intermediate between the two (pl. 4, fig. 18). S. (Exuomphalus) hoff mani is similar to S. (Strapa- rollus) cottrelli in rate of whorl expansion, in the presence of a circumbilical ridge, and in the varia- tion in size and positioning of implanted material. We suggest that it has evolved from S. (Straparot- lus) cottrelli and in the process has acquired a generally larger size, a higher spire, a strong cir- cumbilical ridge, and an angulated whorl profile. The cross section of each whorl has an angular "euomphalid" shape rather than the rounded "strap- arollid" whorl profile. In addition, the implantation of foreign matter apparently is ubiquitous in the population, as though the habit or stimulus for im- plantation was increasing through time. S,. (Euomphalus) winnipegosis occurs in the Win- nipegosis Formation of Manitoba and is thus difficult to relate temporally to the Michigan species. It re- sembles the Rogers City forms in having a circum- bilical ridge, in a rapid whorl expansion, and in general distribution of incrusted material. As it is currently known from a single specimen, we cannot comment on the frequency of incrusted individuals within a population, but would expect it to be high, because in other features the species is comparable to S. (Euomphalus) hoff mani. Although the species is intermediate in spire height between the two Rog- ers City species, the concave upper whorl face is more of a deviation from the "typical Straparollus" profile than either of those forms. In all forms of the second group there is considerable variation in the size of the pieces of implanted material. Neverthe- less, the overall impression is that the first group implanted somewhat smaller pieces of foreign matter than the second group. Straparollus (?Fuomphalus) incrustatus from the Engelmann Formation of Utah bears some resem- blance to the second group in rate of whorl expan- sion and general vagaries of position of scars. All available specimens show cicatrices. There is a flat- tening of the outer whorl faces so that the profile approaches angulation. The species differs from those of the second group in having a narrower um- CONCLUSIONS 21 bilicus and in lacking a circumbilical ridge. It is apparent that this species bears more resemblance to the second group than to the first. Still, it is an open question whether S. (?Wuomphalus) incrus- tatus is distantly related to the second group or com- pletely separate. The other two species discussed in this paper are quite enigmatic in their relationships. Because Strap- arollus (Straparollus) sp. from the Marcellus Shale of New York is known only from a fragment, little can be said. It resembles the first group in slow rate of whorl expansion and general roundness of profile, but it does not have the uniformity of implantation that is so distinctive of that group. Straparollus (?Serpulospira) eboracensis from the Ludlowville of New York is hardly better known. Nevertheless, it is the most dissimilar form because of the rapid rate of whorl expansion. It bears little resemblance to any of the other forms except that it has a rounded whorl profile and implants foreign matter. CONCLUSIONS The implantation of foreign shell material by mod- ern gastropods is a deliberate and purposeful act. The elaborate behavioral antics of Xenophora amply substantiate the conclusion that implantation is not accidental. Presumably this peculiar art is of con- siderable selective value to the animal that practices it. The habit of implantation probably also had selec- tive value for the Paleozoic carrier shells. The act of attaching shell material necessitated long periods of quiescence for the organism. In addition, once the foreign material was attached to the shell, it was nec- essary for the organism to lead a sedentary life, as active creeping about would destroy any effective- ness of camouflage by calling attention to the orga- nism. Thus, the presence of incrusted material suggests that relative immobility was a character- istic of these Devonian euomphalids. Independent of this argument, Yochelson (1971) suggested that dis- junctly coiled forms were adapted to a sedentary mode of life in which the shell lay flat on the sub- strate. In the specimen of S. (Serpulospira) cen- trifuga, both the disjunct coiling and the habit of attachment are seen. The assumption of limited movement and comparison with living Xenophora would support the argument that these forms had moved from a predominantly grazing habit to one of deposit or filter feeding. The presence of large numbers of septa in at least some of the disjunctly coiled forms suggests that the soft parts were shortened and "worm-like" (Yochel- son, 1971, p. 240-241), further reinforcing the notion of essentially a sessile mode of life. The sessility of these Paleozoic euomphalids is thus inferred from three separate lines of evidence: (1) the disjunct coiling of forms like S. (Serpulo- spira), which would preclude anything short of "sitting" on top of soft sediments, (2) the presence of septa, which suggests a shortened, wormlike body, and (3) the camouflage effect of the implanted ma- terials. The cementing habit has evolved independently in several lines. It is known from the Ordovician and Devonian in the euomphalaceans, from the Miocene- Pliocene in the turritellids, and from the Cretaceous to Holocene in the xenophorids. The majority of the Devonian species examined are readily placed in two groups. They differ not only in the size of whorl expansion but also in the degree of implantation. It seems reasonable to conclude that the implanting habit evolved independently in at least two stocks during the Middle Devonian and that not all the incrusted forms are closely allied. If this inference is correct, the erratic stratigraphic occurrence of the forms during Middle and Late Devonian time is far more understandable. North American species of carrier shells associ- ated with Stringocephalus tend toward development of an outer angulation; accordingly, several species have been assigned to Straparollus (Euomphalus). It may be that this outer angulation is better ex- pressed as a flattening of the outer whorl face with subsequent modification of the upper part of the whorl as a direct consequence. Flattening of the outer whorl face is readily interpreted as a more efficient method for allowing attachment to the shell of foreign fragments. We have followed convention in using this subgenus, but we suggest that in this instance the convention is misleading. Although we do not mean to imply that there is no validity to Exuomphalus as it is normally used, we would sug- gest that unusually high-spired forms or those with a poorly developed upper angulation be considered carefully before being automatically assigned to that taxon. Perhaps our views are best summarized by the comments of Ulrich and Scofield (1897, p. 1024) in a general discussion of the euomphalaceans. After noting the occurrence of fragments attached to Euomphalus eboracensis Hall, they stated that Ecculilomphalus undulatus Hall had a similar habit, and its frequent occurrence in several European Devonian Euom- phalidae has been observed by Deslongchamps, Koken and others, and quite recently has led Kayser to propose the new generic term Philoxene (Zeitschr. d. deutsch. geol. Gesellsch., Jahrg. 1889). This peculiar feature reminds one of the recent genus Phorus, but we agree fully with Hall and Koken in attaching very little significance to its presence in these other- wise clearly Euomphaloid shells. 22 DEVONIAN CARRIER SHELLS (EUOMPHALIDAE) FROM NORTH AMERICA AND GERMANY SELECTED REFERENCES Archiac, E. J. A. d', and Verneuil, E. 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J Age correlation.... 14 Amphidesma australe.. 19 angelicoides, Athyris 14 arctica, Atrypa......... 14 Athyris angelicoides. 14 Atrypa...... 12 arctica.. 14 $p... 17 attenuatus, Liromytilus. 14 australe, Amphidesma.... 19 Bag worms 2 borsoni, Tugurium (Troohotugurmm) 8 Brachiopod......... 14 Buechelia tyrrelli 14 ...ll il lenin 17 calculiferum, Tugurium (Trochotugu- REEN) 2, oe des as a, olives seven de 8 CHPETAEL, 3 caribeum, Tugurium (Trochotugurium) .... 3 Carinatina dysmorphostrota 14 CHS8IA .-.. ..i NAA.... 8 Cedar Valley Limestone 10, 14 centrifuga, Straparollus (Serpulospira) ... 8, 16, 19, 21 pl. 3 Cephalopods... 18 conchyliophora, Xenophora. corrugata, Xenophora. 3 Coscinasterias................. 5 cottrelli, Straparollus (Straparollus) ...... 10, 11, 14, 17, 18, 19, 20 ; pl. 4 Crabs .s a RL.... 9 cyclostomus, Euomphalus.. 10 Straparollus (Straparollus) .................. 8, 20, 11, 14, 17, 19, 20 ; pl. 8 portlandensis, Straparollus. 10 Cyrtolites trentonensis............. 7 dysmorphostrota, Carinatina..................... 14 eboracensis, Euomphalus................ 7, 41 Euomphalus (Phanerotinus) . Straparollus (Serpulospira). Eccyliomphalus.. undulatus. Echinochama e Endoptygma.... i 3 Englemann Formation.. Euomphalidae.. Euomphalus..... cyclostomus. eboracensis.. laevis... serpens 6 serpula... 8 (Phanerotmus) eboracenszs T (Euomphalus) hoffmani, Straparollus. 9, 11, 12, 13, 14, 16, 18, 19, 20 ; pl. 4, 5 incrustatus, Straparollus..................... 11, 18, 14, 17, 20 ; pl. 6 Straparoliit$. .... ...ll... 21 winnipegosis, Straparollus + 18, 14,17, 20 pl. 6 exutum, Tugurium (Tugurium) ...... 8 506-182 O - 73 - 2 INDEX [Italic page numbers indicate major references] Foraminifera. Fossil localities. See Specimen localities. Furnish, William, fossil-location descrip- se 32rd che dermis devant 10 Gastrocopta pentodon.... 2 Gravel Point Formation 14 (Haliphocbus) solaris, Tugurium................. 3 THORN 31.0.0 ae ile earth 902 3, 6 helvacea, Tugurium (Trochotugurium) ... 3 hoffmani, Straparollus (Euomphalus) ...... 9, 11, 12, 13, 14, 16, 18, 19, 20 ; pl. 4, 5 For . phore : 2. ... insult 2 Ikatere... mcrustata, Thysanophora .............................. 2 incrustatus, Straparollus (Euomphalus) .. 11, 13, 14, 17, 20 ; pl. 6 Straparollus - (Straparollus) .......... 11.1419 indicum, Tugurium (Trochotugurium) ...... 3 eS .-- 1000.00, n 04 3 konot, - inl dlc imens 8 laevis, Euomphalus. Philoxene............ y Straparollus (Straparollus) .................. 8; 8, 11, 14, 16, 19 ; pl. 8 lamberti, Tugurium (Tugurium) ...... 15 souverbie, Tugurium (Trochotugu- rium) .. 8 Lamelliphorus........... 3 Liromytilus attenuatus 14 Ludlowville Formation.. 14 Lytospira. 6 norvegica T subuloidea. 6 Maoricré pie.. a 2 .. a sl.. dente elves i a scn. pl. 2 Marcellus Shale.. 14 modulids............ 3 6 mortoni, Straparollus (Straparollus) ...... 9, 14, 16, 17, 18, 20 ; pl. 6 multispina, Straparollus (Philoxene) ...... 9 Navbiighe . .ca deel A n a AHL NRN 18 neozelanica, Xenophora 8.4. it: pl. 2 norvegica, Lytospira...... T Omphalocirrus sp.. 14 Omphalotrochus..... 13 ophirensis, Straparollus. 14 Of tis. ta Am a. inn.. $ d Oyster drille 22.2 ;... A.A.... mo.. chon 5 pallidula, Xenophora... pentodon, Gastrocopta 2 Phanerotinus. £ (Phanerotinus) eboracensis, Euomphalus 7 philosophus, Phil0®ene.................................... 6 Philozene.. laevis. 6 ...... ctu nl... 6 (Philozene) multispina, Straparollus. 9 21 Pleurotomaria g portlandensis, Straparollus cyclostomus.... 10 Page ...s. 0s 0a alii dol ied 6 Pupillidae 2 quadrangularis, Samarangia................ 2 Rogers City Limestone.................... 11, 14 Sagdidae 2 Samarangia quadrangularis.. 2 sapiens, Stringocephalus.. A.... 2; $ Scofield, W. H., and Ulrich, E. O., valid- ity of takonomy.............l...... 21 Selected references... 22 serpens, Euomphalus.. 6 serpula, Euomphalus 8 Straparollus (Serpulospira) 8 Serpularia......... 8 Serpulorbis sp. 2 Serpulospira 7 (Serpulospira), Straparollus. 21 centrifuga, Straparollus 8, 16, 19, 21 ; pl: 8 eboracensis, Straparollus.... ¥ 7, 14. 17, 21 ; pl.8 serpulg, . ces.. 8 Shank, Paul, observations on cementation 4 Shipworm. -.. .. mallee one 19 Skaneateles Formation 14 solaris, Tugurium (Haliphoebus) 8 Solarian sis. .8 sacs ,n. mn 8 souverbic, Tugurium (Trochotugurium) lamberti... 3 Specimen localities, Bikin 2 Canada. 13, 14, 20 pl. 6 Florida.. 4 Germany, Bohemia.. 6 Bucheler bed...... evolutionary groups. Indian Ocean.. Tows Japan... Mexico... Michigan.. Nevada.. New York.. evolutionary groups.. ¥ 21 New Zealand.... f 2 North America, evolutlonary groups 19 Pacific Océan ..... lsu. .libs, alent ad 2. 6 Philippines.... Scandinavia... Tennessee. Trinidad... Uigh..~.:. Venezuela. Wednesday Island. Sponges......... Springvaleia.... Starfish Sire mar olite... . .... cs onlt a manda 7, 8, 19, 20 cyclostomus portlandensis 9 cll. sloan lol (Euomphalus) .. hoff mani... : 1112131416181920 p145 25 26 Page Straparollus - Continued (Euomphalus) - Continued incrustatus... ./ 41, 18, 14, 17, 20 $ pl. 6 winnipegosis ... 48, 14, 17, 20; pl. 6 (Philozene) multispina. 9 (Serpulospira) ................ 21 centrifuga. 8, 16, 19, 21 ; pl. 3 eboracensis 7/14, 17, 21; pl. 3 SETDHLL ...is... 8 (Straparollus) cottrelli. 10, 11, 14, 17, 18, 19, 20 ; pl. 4 ... ..., 1.0.2: tienen bea 8, 10, 11, 14, 17, 19, 20 ; pl. 3 11, 17, 19 laevis.... L #, 0, 11, 14, 16, 190; plas mortoni . 9, 14, 16, 17, 18, 20 ; pl. 6 SDAA Ai 0 Aim mice mil 9, 14. 17; 21 ; pl: 5 (Straparollus) cottrelli, Straparollus........ 10, 11, 14, 17, 18, 19, 20 ; pl. 4 cyclostomus, Straparollus...................... 8, 10, 11, 14, 17, 19, 20 ; pl. 3 incrustatus, Straparollus 11, 17, 19 laevis, Straparollus............ 8, 9, 11, 14, 16, 19 ; pl. 3 mortoni, Straparollus................... 9, 14, 16, 17, 18, 20 ; pl. 6 sp., Straparollus................ 9, 14, 17, 21 ; pl. 5 Stringocephalus 14, 21 sapiens. 14 INDEX Subrensselandia sp.. subuloidea, Lytospira.. Térsdo. ..... . Thysanophora horni incrustata..... Traverse Group.. trentonensis, Cyrtolites. (Trochotugurium) borsoni, Tugurium...... calculiferum, Tugurium.. caribeum, Tugurium........ helvacea, Tugurium.. indicum, Tugurium.... lamberti souverbie, Tugurium longleyi, Tugurium............... Tugurium. Tunicates.......... Tugurbm................ (Haliphoebus) .. 0. (Trochotugurium) . borsoni. calculiferum. caribeum.... helvacea indicum... lamberti souverbie longleyti................... (Tugurium) .. exutum.... Page 14 f fa co to o» to os os G5 to co to on Go on m bo C oo to to to oo to to <1 gm bo bo tD Page Tugurium - Continued (Tugurium) - Continued lamberti.. 15 (Tugurium) exutum, Tugurium.. 3 lamberti, Tugurium.......... 15 Tugurium... 8, 6 turritellids....... EyrP EUL, 000, lic. 14 Ulrich, E. O., and Scofield, W. H., validity of 21 undulatus, Eccyliomphalus Vermelid -...... cll. winnipegosis, Straparollus (Euomphalus) 18, 14, 17, 20 ; pl. 6 Worm burrows and tubes.............................. 2, 8 Xenophora...... 1, , 18, 21 caperata.. 3 compared to Lytospira.. T conchyliophora............... 8, 16 corrugata 8 konoi........ % 3 neozelanica... 3, 4, 17 ; pl. 2 pallidula........ $. 17: p11 role of implantation.. 6 selection of material.. 17 size of implanted material.. 3 2 Xenophoridae............ .-..... t h U. S. GOVERNMENT PRINTING OFFICE : 1973 O - 506-182 PLATES 1-6 Contact photographs of the plates in this report are available, at cost, from the U.S. Geological Survey Library, Federal Center, Denver, Colorado 80225. PLATE 1 [Al figures X 11 _ FIGURES 1-5. Xenophora pallidula (Reeve). 1, 5. Oblique apical and side adapertural views of USNM 238277, U.S. Bur. Fisheries (USBF) station 5408, off Point Pinulacau, Cebu, Philippines, 159 fathoms, in green mud. The material implanted on the earliest whorls of this specimen has been broken off, leaving attachment sears, whereas material implanted on adult whorls is still attached. The earliest implanted materials are rounded clam shells, which were attached by their outer surface. Then two small corals were attached and, on the final whorl and a half, six different species of high-spired gastropod shells. The specimen was subsequently incrusted with serpulid worm tubes and solitary corals on the attached snails at lower center and right. 2. Apical view of USNM 238192, USBF station 5392, off Desbacado Island, Philip- pines, 135 fathoms, in green mud. The early whorls of this specimen are obscured by incrusting organisms, such as serpulid worm tubes and a large bar- nacle (center right). Most of the implanted material on the early whorls is small corals. On the adult whorls it consists of larger solitary corals and elongated gastropod shells. 3. Oblique apical view of USNM 248411, USBF station 5278, north of Ambil Island, Luzon, Philippines, 102 fathoms in fine sandy mud. The earliest implanted ma- terial on this specimen was small pebbles, followed by two small corals and elon- gated gastropod shells. Note the dark-gray shell below and the very dark gray pebble above in the midst of lighter colore pink to gray shells. 4. Oblique apical view of USNM 243374, USB station 5265, Butangas Bay, Luzon, Philippines, 135 fathoms, in sandy mud. The specimen began by implanting pebbles; this was followed in the adult whorls by implantation of a mixture of pebbles, clam shells, and high-spired snails. GEOLOGICAL SURVEY PROFESSIONAL PAPER 824 PLATE 1 XENOPHORA PALLIDULA REEVE PLATE 2 [All figures X 1%] FIGURES 1-5. Xenophora neozelanica Suter. All specimens captured by prawn trawl with tickler, 5 miles east of Takatau Point, north of Auckland, New Zealand, in 27 to 30 fathoms of water. Station 314 (22-9-71) of Ikatere, New Zealand Marine Department. Lat 36°2230" §., long 174°59'24" E. Substrate consists of dark-gray mud rich in organic matter, with abundant shell cover. 1. Apertural view of specimen in normal feeding position with foot held off substrate. Proboscis reaching out to scrape algae off shell. Note mucus secreted by foot and the operculum in a vertical position. 2. Basal view of animal, showing inverted position of soft parts typical of search be- havior for shell material. The proboscis and tentacles are against the substrate while the broadly expanded propodium searches for foreign matter to be implanted onto its shell. A large slipper shell (Maoricrepis) is on the base at the right center of the figure. 3. Oblique anterior view of male in typical feeding behavior. Tentacles and proboscis search for food with foot suspended off the substrate. The basal part of penis is seen emerging from the right side of the snail's muscular column. 4. Side view of animal during search behavior. The soft parts are inverted beneath tentlike canopy of the shell; the proboscis lifts the shell by pushing against the substrate while the propodium searches for material suitable for implantation. 5. Basal view showing animal engaged in cleaning activity. The broad propodium is directed down to the right, the metapodium is not in contact with the substrate and therefore is relatively narrow. The proboscis is curved around to clean the underside of the operculum. The mantle extends almost to the outer lip, and the gill is just to the left of the propodium. The black dots are feces behind the metapodium. GEOLOGICAL SURVEY PROFESSIONAL PAPER 824 PLATE 2 saat XENOPHORA NEOZELANICA SUTER PLATE 3 FIGURES 1-3. Straparollus (Straparollus) laevis (Archiac and Verneuil) (p. 8). Apical, oblique basal, and side views (x 2) of hypotype, USNM 58498, Paffrath beds, Germany. Note the uniform spacing of the scars at the periphery. f 4, 5. S. (Straparollus) ?Haevis (Archiac and Verneuil) (p. 9). Side and basal views (x 2) of hypotype, USNM 63255, Paffrath beds, Germany. Note even spacing of attachment sears and their position low on the outer whorl face. 6, 7, 12-18. S. (Straparollus) cyclostomus (Hall) (p. 10). From Cedar Valley Limestone (X 1%). 6. Adapertural view of hypotype, USNM 183657, from quarry on Sweetland Creek, Muscatine County, Iowa. This is one of the largest specimens in this collection, but there are no signs of any attachment. 7. Side view of broken hypotype, USNM 183656, from 5 miles above Muscatine, Iowa. This rather large specimen has only a single attachment sear, well back from the aperture. 12-15. Basal, oblique apical, apical and apertural views of hypotype, USNM 183655, from 5 miles above Muscatine, Iowa. This large rugose specimen has many irregularly spaced attachment sears. 16-18. Apertural, apical, and basal views of hypotype, USNM 183658, from quarry on Sweetland Creek, Muscatine County, Iowa. This small well-preserved specimen shows no cicatrices. 8-11. S. (Serpulospira) centrifuga (F. A. Roemer) (p. 8). Apical, oblique basal, apertural, and oblique apical views (x 2) of hypotype, USNM 183651, collected from the Paffrath beds near Bergische Gladbach near Cologne, Ger- many. This specimen has the disjunct coiling so typical of the subgenus, but also has attachment sears, evenly distributed at the periphery, much as in S. (Straparollus) lae- vis; compare with figures 1-3. a 19-21. S. (?Serpulospira) eboracensis (Hall) (p. 7). Apical, oblique apical, and side views (x 2) of lectotype, AMNH 48190 , from the Lud- lowville Formation near York, N.Y. Although this specimen is so poorly preserved that its subgeneric designation is questionable, it does have the encrusting habit, with the impressions of the fragments still intact. GEOLOGICAL SURVEY PROFESSIONAL PAPER 824 PLATE 3 STRAPAROLLUS (STRAPAROLLUS) AND S. (SERPULOSPIRA) PLATE 4 FIGURES 1-12. Straparollus (Straparollus) cottrelli n. sp. (p. 11). All specimens from unit 1 of the Rogers City Limestone of northeast Michigan, except specimen shown in figure 11, which is from unit 2. 1, 4. Apical and basal views (x 2) of holotype, USNM 183659. Note the essentially rounded whorl profile, cireumbilical ridge, and the two immature specimens of S. (S.) cottrelli that have been implanted. 2, 5. Basal and apical views (x 2) of paratype, UMMP 22375. This is a crushed speci- men which still shows the essential features of the species. Note the implanted bellerophontid and immature specimen of S. (S.) cottrelli, 3. Oblique apical view (x 2) of paratype, USNM 183660. 6. Oblique apical view (x 2) of paratype, USNM 183679. Although this is a large specimen, there is only one discernible cicatrix on it. 7-10. Basal, apical, apertural, and adapertural side views (x 1) of paratype, USNM 183661. This slightly crushed specimen has abundant attachment sears located consistently at the periphery. 11. Oblique apical view (x 2) of paratype, USNM 183662. This individual accreted a variety of shells to its own. 12. Apical view (x 1) of paratype, USNM 183663, which shows that material was implanted in the second preserved volution. - 13. S. (S.) cf. S. (S.) cottrelli. Basal view (% 1) of figured specimen, USNM 183664. This specimen is from unit 3 of the Rogers City Limestone and is thought to be somewhat transitional in form between S. (S.) cottrelli and S. (Euomphalus) hoff mani. 14. Latex cast (x 1) UMMP 22424, of a block from the basal unit of the Rogers City Lime- stone. The well-sorted nature of these deposits suggests sorting by current action, prob- ably by waves in a restricted lagoonal or supratidal habitat. More than 50 percent of the specimens in this block are S. (S.) cottrelli. GEOLOGICAL SURVEY PROFESSIONAL PAPER 824 PLATE 4 F ( $54 y fig; Rat X7 'yes #34 STRAPAROLLUS (STRAPAROLLUS) PLATE 5 FIGURES 1-19. Straparollus (Euomphalus) hoffmani n. sp. (p. 12). All specimens collected from the upper three units of the Rogers City Limestone in northeastern Michigan. 1. Oblique apertural view (x 1) of paratype, USNM 183666, a small exceptionally well preserved specimen which shows the cireumbilical ridge and has few attachment scars. 2, 3, 6. Oblique basal, oblique apical, and side views (x 1%) of paratype, UMMP 22374. 4, 8, 12. Side, basal, and apical views (x 2) of paratype, UMMP 22370. This is an unusual immature specimen in that it has not yet developed the angulation between the upper and outer whorl faces. It bears just one very large cicatrix. 5. Side view (x 1) of paratype, USNM 183667. 7, 11. Oblique apical and apical views (x 1) of holotype, UMMP 22369. This large speci- men shows the angulation between the flattened upper and outer whorl faces and abundant attachment sears. 9. Apertural view (x 1) of paratype, USNM 102938, an unusually high-spired indi- vidual. 3 10, 13, 14. Apertural, adapertural, and oblique basal views (x 1) of paratype, UMMP 22372. Although implantation scars are common over the early whorls, the last half volu- tion is free of sears. 15, 18, 19. Apertural, side, and basal views of paratype (x 1%), UMMP 57888. This is an unusually high spired form and one of the largest specimens; cicatrices almost abut each other. 16. Apertural view (x 1%) of paratype, USNM 183665, a large moderately high spired form. 17. Side view (x 2) of paratype, UMMP 57889. This immature specimen, even at a young stage, has the flattened outer whorl face and the angulation separating the upper and outer faces. 20. Straparollus (Straparollus) sp. (p. 9). Oblique apical view (x 2) of figured specimen, USNM 183652, from the "Cardiff Shale Member" of the Marcellus Shale, Hamilton Group, 3 miles south of Peterboro, N.Y. GEOLOGICAL SURVEY PROFESSIONAL PAPER 824 PLATE 5 STRAPAROLLUS (EUOMPHALUS) AND S. (STRAPAROLLUS) PLATE 6 FIGURES 1-4. Straparollus (Straparollus) mortoni n. sp. (p. 9). From the lower part of the Gravel Point Formation at the Marvin quarry, SW WNW 4% sec. 7, T. 34 N., R. 1 W., Cheboygan County, Mich. 1, 2. Apical and oblique apical views (X 2) of latex cast of holotype, USNM 183653, showing numerous cicatrices evenly distributed around the periphery. 3, 4. Slightly oblique side and apical views (X 2) of latex cast of paratype, USNM 183654, higher spired than the holotype. 5-18, 20. S. (?Fuomphalus) incrustatus n. sp. (p. 13). From the Engelmann Formation, at USGS loc. 5829-SD, Thomas Range, Utah. 5-7. Apertural, apical, and basal views (x 3) of paratype, USNM 183677. 8. Side view (x 3) of broken paratype, USNM 183676, showing whorl,cross section and absence of cireumbilical ridge. 9. Basal view (x 1) of paratype, USNM 183675. 10. Adapertural side view (x 2) of paratype, USNM 183674, with several scars of attachment on body whorl. 11. Side view (x 3) of fragmentary paratype, USNM 183673, showing sears penetrat- ing the silicified shell. 12, 18. Adapertural and cross-sectional side views (x 3) of paratype, USNM 183670. Note fragment attached to penultimate and body whorls and additional scars on body whorl. 13, 14, 16. Side, basal, and apical views (x 3) of paratype, USNM 183671, which has at- tached a juvenile specimen. 15. Oblique side view (x 3) of fragmentary paratype, USNM 183672, with two large scars on the body whorl. 17, 20. Adapertural and apical views (x 1) of holotype, USNM 183669. In spite of erush- ing of the body whorl, growth lines are clear; implantation sears are prominent on the penultimate whorl. 19, 21. S. (Euomphalus) winnipegosis n. sp. (p. 13). From the Winnipegosis Formation about % mile west of The Narrows of Lake Mani- toba. Side and oblique apical views (x 2) of latex cast of holotype, USNM 183668. This shows concave upper whorl surface and flattened outer whorl face with angulation be- tween; attachment sears are abundant on outer whorl face. GEOLOGICAL SURVEY PROFESSIONAL PAPER 824 PLATE 6 STRAPAROLLUS (EUOMPHALUS) AND S. (STRAPAROLLUS) EARIA SCIENCES LIBRARY 230 Earth Sciences Bldg. _ nave 1° 642-2997 EARTH Sciences R 4 Ostracodes from Lower Devonian Formations in Alaska and Yukon Territory CEOLOGICAL SURVEY PROFESSIONAL P APER 8 2 5 PC 75 v: #25 U < SD. Ostracodes from Lower Devonian Formations in Alaska and Yukon Territory By JEAN M. BERDAN ard M. J. COPELAND GEO LG SURVEY PROFESSIONAL PAPER 825 Descriptions and illustrations of an ostracode assemblage comprising 73 taxa, including 6 new genera and 33 new species, of potential value for regional correlation in the Arctic province UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1973 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 73-600212 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $1.75 (paper cover) Stock Number 2401-02407 CONTENTS Page ADSTT ACL . a= ss a - m m a s e at me o oss as bt oe bn on in as me e i un s hs an ne me holes e e aa ue m me' e 1 | Systematic paleontology-Continued ATROAUCULON | © .. .. .. .. ..... .. . .. ..... coa o. s oo ul oo ne anne he nn ne no he ie no be mln be male mune 1 Order PodocdPida Acknowledgments _________________________--- 1 Genus Bairdia M'Coy, 1844 _______________ Stratigraphy and. sedimentation __.............~... 2 Genus Rectobairdia Sohn, 1961 ........._.. A59 and corrleatlon """""""""""""""" 2 Genus Bairdiolites Croneis and Gale, 1939 P ia reer epe raat C Genus Newsomites Morris and Hill, 1952 Systematic pAIGONLOIOGY 8 i * s= Order Palneocoplda 9 Genus Acanthoscapha Ulrich and Bassler, Genus Mesomphalus Ulrich and Bassler, 1913 9 1928 - Genus Treposella Ulrich and Bassler, 1908 - 9 Genus Shidelerites Morris and Hill, 1951 ___ Genus Beyrichie M'Coy, 1846 ____________ 10 Genus Beecherella Ulrich, 1891 ___________ Genus Yukonibeyrichia n. gen ___________ 11 Genus Camdenidea Swain, 1958 ___________ Genus Alaskabolbina n. gen ______________ 14 Genus Tricornina Bouéek, 1986 ___________ Genus Ogilvites n. gon -----------.------ 15 Genus Bicornina Jordan, 1964 ____________ Genus Abditoloculina Kesling, 1952 _______- 16 Genus Berounella Boutek, 1986 ____________ Genus Parqbolbma. Swartz, 1936 _______-- 17 Genus Bairdiocypris Kegel, 1982 _________ Genus Hollina Ulrich and Bassler,1908 ___ 17 o Genus Falsipollex Kesling and McMillan, Soe Ammo O " . ot 1. RN t rl: 17 Genus Bairdiohealdites McGill, 1968 ______ Genus Hollinella Coryell, 1928 ____________ 18 Genus Praepilatina Polenova, 1970 _______- Genus Abortivelum n. BCM |- ees 19 Genus Barychlllm Ulrich, 1891 ........... Genus Adelphobolbina Stover, 1956 ________ 19 Genus Trypetera Kesling, 1954 ____________ Genus Flaccivelum Kesling and Peterson, Genus Voronina Polenova, 1952 ___________ DIB os oe o o o mone a it no oo at 4 m oe m hos to ne ot o h h e he h a n hee 21 Genus Cavellinae Coryell, 1928 ____________ Genus Infractivelum n. gen _____________- 21 Genus Tubulibairdia Swartz, 1986 _________ genus 00212022?”sz KeSIingigég52 -------- 22 FPachydomellid Indet, 1 enus Obotritia Adamczak, 1968 _________. 23 ya Genus Kirkbyella Coryell and Booth, 1983 . 24 Zachydomfa o Smdet. a ____Ii__(_1_._ _________ Coenus Anualies Porores. 1050, _...... 24 enus Eriella teyart and 19456 .. Genus Suboarotichites n. gon. ______________ 27 Genus Neocraterellina Krandijevsky, 1968 __ Genus Libumella Rozhdestvenskaya, 1959 __ 27 Genus Microcheilinella Geis, 1983 ________-- Genus Neoaparchites Bouéek, 1986 _________ 28 Ostracode IMdGE, 1 Genus Aparchites Jones, 1889 ____________ 28 Ostracode indet. 2 Genus Eukloedenella Ulrich and Bassler, Ostracode indet. 8 TJ 2D . se l nene co ne ml ae ae he oa tn mion a a hain t ae He asin ol he mae e nere ma oa 29 | References CHOU .._ nun nolo nie a ieee m em mene m nemo bn be mn ae Genus Polomiella Giirich, 1896 ____________ 80 | Index . . .. ... . 22 c. 2 ll cdo no ooo naan nnn ea eee eni uel ILLUSTRATIONS [Plates follow index] Mesomphalus? and Treposella. Beyrichia (Beyrichia). Beyrichia (Scabribeyrichia). Yukonibeyrichia. Alaskabolbina and Alaskabolbina?. Ogilvites, Abditoloculina, Abortivelum, Adelphobolbina, and Hollina. Hollinella, Adelphobolbina, and Falsipollex?. Obotritia?, Chironiptrum, Flaccivelum, Parabolbina, and Infractivelum. Kirkbyella, Hanaites, and Subarctichites. Libumella, Necaparchites?, and "Aparchites." 5 3 © so go u > prgm go bo pa a III Page 30 30 31 31 31 PrATE 11. 12. 13. 14 FIGURE 1. 2. 8-7. TABLE 1. CONTENTS Bairdia, Bairdiolites?, Beecherella?, Acanthoscapha, Rectobairdia, Shideler- ites, Eukloedenella, and Poloniella (Framella). Tricornina, Bicornina, Berounella, Bairdiocypris?, Bairdiocypris, and Kure- sarrig. Camdenidea, Praepilatina, Bairdiohealdites?, and Voronina. Eriella?, - Microcheilinella?, - Neocraterellina?, Cavellina - (Invisibila) ?, Newsomites?, Barychilina?, Tubulibairdia, and ostracodes indet. Page Index map showiig locations of sections from which ostracodes were collected in Alaska and Yukon Territory ___________________ 2 Diagrammatic sections of the McCann Hill Chert and Michelle and Prongs Creek Formations showing positions of ostracode collec- -,... .- +o le a o sam oe a n se he Tal ce ne sta co t e t an he ehe se Te md ce ad he ae fm ha he i ns bu ha s unos oe tn e we an n 4 Scatter diagrams showing length versus height of : 3. Béyrichin (Beyrichia) brabbi _________.____~uL.cclllu.l.. 11 4. Beyrichia (Scabribeyrichia) churkini ____________________ 12 5, Yaukonibeyrichit YUEORENEIE 18 6, Chirontptrum HMITOPIE 23 Ts - HARLES - DFEUIE . .. ._ -n. cl .. 2 t al bres ae nl e ceed mee al he al s an as hn lean 'or ma Gn mi ee im n ht e o ms 26 TABLE Ostracode taxa described in this paper and the formations and col- lections in which they OCCUT P 6 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY ) By M. Beroan and M. J. COPELAND ABSTRACT Residues of samples, dissolved in acetic and formis acid from the limestone and shale member of the McCann Hill Chert of eastern Alaska and the Michelle and Prongs Creek Formations of Yukon Territory have revealed the presence of a varied, silicified ostracode fauna. This fauna may serve as a basis for correlating strata from the Alaska-Yukon international boundary near lat 65° N. northeastward for more than 200 miles. Of the more than 40 genera present, hollinaceans and beyrichiaceans are the most distinctive. The hollinaceans find their closest affinity with genera from lower Middle Devonian (Eifelian) beds from the midcontinent region of North America, and the beyrichiaceans with genera from Lower Devonian and Silurian strata of Appalachian North America and of Europe. Conodonts and dacryoconarid tentaculites indicate that the age of the collections from which the ostracodes were obtained is late Early Devonian (Emsian), but the ostracode assemblage reported here does not resemble any described Emsian fauna. These ostracodes are considered to represent a provincial assemblage with some Silurian survivors and some precur- sors of Middle Devonian forms which subsequently mi- grated to Eurasia and central North America. In all, 73 taxa, including 6 new genera and 33 new species, are de- scribed and illustrated. INTRODUCTION The McCann Hill Chert of Alaska and the Michelle and Prongs Creek Formations of Yukon Territory, Canada, contain a large fauna of invertebrate fos- sils which includes a varied and abundant assem- blage of ostracodes. Some of the silicified ostracodes from the McCann Hill Chert have been listed and illustrated by Berdan (in Churkin and Brabb, 1967), and silicified ostracodes from the Michelle and Prongs Creek Formations have been listed by Cope- land (in Ludvigsen, 1970). Copeland (in Norris, 19672, sections 16, 17, and 19) also reported several nonsilicified specimens from the Michelle Formation in the vicinity of Hart and Blackstone Rivers, Yu- kon Territory. The present paper is the first com- prehensive description of the silicified ostracode assemblage from these formations. 1 Geological Survey of Canada, Ottawa, Ontario, Canada. The first of the silicified ostracode faunules was found in USGS collection 6492-SD, from the basal limestone and shale member of the McCann Hill Chert, one half mile west of Hillard Peak, Alaska, and 3.4 miles N. 41° W. of International Bound- ary Commission monument 105, (64°5703" N., 141°04'05" W.). From this collection, Berdan (in Churkin and Brabb, 1967, table 1, pl. 4) reported 20 species belonging to 18 genera, and illustrated 14 of these species. Later, similar silicified ostracodes were obtained by Ludvigsen (1970) from five sec- tions (I-V) in Yukon Territory, from the Michelle Formation of Blackstone -and Hart Rivers (about 65°41" N., 137°00' W.) and the Prongs Creek Forma- tion of Solo Creek (65°51.4' N., 134°15.5 W.). Cope- land (in Ludvigsen, 1970, p. 426) listed 10 species of 9 genera from each of the Michelle and Prongs Creek Formations. In all, the present authors pre- viously recognized 19 known and 2 unnamed ostra- code genera. Further study of the original and addi- tional collections has resulted in this report, in which 73 ostracode taxa are described and illus- trated. Of these, 6 genera and 33 species are new. The ostracode occurrences are scattered from near the Alaska-Yukon international boundary at lat 65° N. for more than 200 miles northeastward to eastern Yukon Territory (fig. 1). Although many of the species are known as yet from only one collection or locality, some of them are widely distributed, and the similarity of the ostracodes on the generic level suggests that they are approximately the same age. The silicified specimens described here may serve as a basis for widespread correlation within the Yukon Shelf of Alaska and Yukon Territory and, in Yukon, across the trough of the Richardson Mountains. Some of the taxa are similar to described species from the Devonian of Asiatic and European parts of the U.S.S.R. and may indicate routes of migration during the Devonian. ACKNOWLEDGMENTS We are grateful to R. Ludvigsen, Calgary, Alberta, for permission to describe the ostracode faunules 1 2 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY ARCTIC 4 «Barrow cBuiukoexur '%92 SEA 7 166° Cape Lnsburn / or- 06°69, - 170° /’ 64° St Lawrence | 68° A St Matthew Ik I Pribilof Islands /s 56° OCEAN GULF OF ALASKA 0 100 200 MILES 603405 # h*" {IPS. Ao a Pdfl. “LE“ l); < s ® a# f*** PACIFIC o cE aN FIGURE 1.-Locations of measured sections from which ostracodes have been collected in Alaska and Yukon Territory. 1, Type section of McCann Hill Chert described by Churkin and Brabb (1965) ; 2, sections II and III of the Michelle For- mation described by Ludvigsen (1970); 3, section IV of the Michelle Formation described by Ludvigsen (1970); 4, section I of the Michelle Formation described by Ludvigsen (1970); 5, section V of the Prongs Creek Formation de- scribed by Ludvigsen (1972). obtained by him in Yukon Territory during the sum- mer of 1968 while he was employed by Gulf Oil, Canada, Limited. Appreciation is expressed to R. Ludvigsen, to A. C. Lenz, University of Western Ontario, and to A. W. Norris, Geological Survey of Canada, for revision and comments on the Canadian stratigraphic part of the paper, and to Michael Churkin, Jr., E. E. Brabb, and J. T. Dutro, Jr., all of the U.S. Geological Survey, for review of the Alaskan stratigraphic part of the paper. I. G. Sohn, U.S. Geological Survey, and Thomas E. Bolton, Geo- logical Survey of Canada, critically reviewed the manuscript. STRATIGRAPHY AND SEDIMENTATION Throughout the area under discussion, strata of the McCann Hill Chert and Michelle and Prongs Creek Formations overlie graptolitic shale of the Road River Formation containing Monograptus yukonensis Jackson and Lenz, 1963, which according to Jaeger (1970, p. 174-175) is Early Devonian in age (Siegenian? to possibly late Emsian). In the west, the contact of the McCann Hill Chert with the Road River Formation appears to be accordant in the section from which the ostracodes were obtained, although there is possible evidence of a stratigraphic break between the formations-a single cobble of graptolitic shale in the basal McCann Hill Chert (Churkin and Brabb, 1965, p. 181; 1967, p. 281). According to Ludvigsen (1970, p. 412), in the Hart River-Blackstone River area, the Michelle Forma- tion has a gradational contact with the Road River Formation, although Norris (1967b, p. 758) sug- gested that the contact may be unconformable. The STRATIGRAPHY AND SEDIMENTATION 8 contact of the Prongs Creek Formation with the Road River in the Solo Creek area has not been de- scribed in detail, but in the area that includes Solo Creek, Norris (1967hb, p. 770) stated that the contact is within shales and was tentatively drawn above the highest uccurrence of monograptids, although farther north at Trail River the contact is an ero- sional unconformity. Ludvigsen (1972, p. 302) also drew the contact of the Road River and Prongs Creek immediately above the highest occurrence of graptolites. The McCann Hill Chert in its type section, from which the ostracodes described in this report were obtained, is abruptly overlain by the lowermost sand- stone beds of the Nation River Formation (Upper Devonian). According to Churkin and Brabb (1965, p. 181; 1967, p. 232-233) there is no evidence for a stratigraphic break at the contact, and the upper part of the McCann Hill contains spores similar to those in the overlying Nation River; consequently, the formations are probably conformable. The Mi- chelle Formation is overlain by the Ogilvie Forma- tion in the Hart River-Blackstone River area; the contact is sharp and may represent a disconformity (Norris, 1967b, p. 770; Ludvigsen, 1970, p. 412; 1972, fig. 2). The Ogilvie is considered to be Early and Middle Devonian in age by Ludvigsen (1972, fig. 2). The section from which ostracodes were ob- tained in the Prongs Creek Formation is incomplete, and the contact of the Prongs Creek with the over- lying formation is unknown. Norris (19676, fig. 4) postulated a change of facies in the area in which this section occurs. The regional relationships and correlation of the McCann Hill Chert and the Michelle and Prongs Creek Formations have been discussed by Churkin and Brabb (1967), Lenz (1967, 1972), Norris (1967b), and Ludvigsen (1972). Details about the type locality of the McCann Hill Chert and the asso- ciated faunas are given by Churkin and Brabb (1965, p. 184, figs. 2, 4) ; the locality is also shown on a geologic map of the Eagle (D-1) quadrangle, Alaska (Brabb and Churkin, 1965). Details of many sections of the Prongs Creek and Michelle Forma- tions in Yukon Territory have been described by Norris (1967a, 1968). The general character of the lithologies of the McCann Hill Chert and the Michelle and Prongs Creek Formations in the sections from which ostra- codes are described in this report and the strati- graphic position of the collections within the sec- tions are shown in figure 2. The McCann Hill Chert is a 200- to 1,000-foot-thick sequence of thinly bedded, laminated light-gray to black chert alternat- ing with siliceous shale and shale, and has a 250-foot- thick limestone and shale member at its base (Chur- kin and Brabb, 1965, p. 180, 181). The basal lime- stone and shale member, from which the ostracodes were obtained, consists of lenticular beds of dark- gray bioclastic limestone interbedded with dark- gray to grayish-black calcareous shale, siltstone, chert grit, and laminated limestone (Churkin and Brabb, 1965, p. 180). According to Ludvigsen (1970, p. 410, 412), in the three sections from which col- lections were made, the Michelle Formation "con- sists of moderately resistant, grey and buff-orange weathering, platy to thick-bedded argillaceous lime- stone with minor non-argillaceous limestone and cal- careous shale." The argillaceous limestone is dark gray to black, micrograined to very fine grained, and some beds are fetid. The Prongs Creek Formation on Solo Creek is "a drab sequence of unfossiliferous, black, calcareous shales with interspersed lenses and beds of breccia composed of limestone, dolomite, or completely replaced by silica" (Ludvigsen, 1972, p. 302). These fossiliferous breccias are considered by Norris (1968, p. 23) and Ludvigsen (1972, p. 302) to have been deposited by turbidity currents. Hand specimens of the McCann Hill Chert, from its type section, that have yielded silicified ostra- codes (USGS collns. 6492-SD, 7082-SD, and 7033- SD) are gray bituminous bioclastic limestone in which many of the megafossils are broken, suggest- ing a high-energy environment. Two samples from the McCann Hill (USGS collns. 7037-SD and 7038- SD), which were collected from outcrops 300 feet east of the type section and are therefore not shown on figure 2, are also bioclastic but are more siliceous and include a considerable amount of chert. These samples were described as being from thin beds of limestone conglomerate in a shale sequence (Brabb, written commun., 1963). In one of these collections, USGS collection 7037-SD, the ostracodes are in gen- eral smaller; many juvenile specimens occur, and also many species that have not been found in the other collections. USGS collection 70388-SD, which is only 5 feet higher than USGS collection 7037-SD, contains virtually the same assemblage as in USGS collections 6492-SD, 7032-SD, and 7033-SD from about 10 feet of the type section. The differences be- tween the ostracode assemblage in USGS collection 7037-SD and that in the other collections is believed to be due to local facies control rather than different stratigraphic position. Hand specimens of Ludvigsen's collections from the Michelle and Prongs Creek Formations were not available for study. 4 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY ALASKA 300 FEET YUKON McCann Hill Chert -_- 200 100 o | va "ue Michelle [ecesees | «--- -& a 116 MILES 12 MILES A =- @, II-14 o «» _ we __ «an It- 13 (a- < u-11 @ e a J «a» a m Nee. - (-~ s" I1 -10 <- & «ame USGS Colin. 7032-SD <] USGS Colin. 6492-SD USGS Colin. 7033-SD III _______________ L-} - E X P L A N A T I 0 N _L. -b o._K Calcareous shale «- «- « Chert, bedded Conglomerate Graywacke Siliceous shale TERRITORY Prongs Creek Formation Formation v Met SL SLL el AY 13 MILES 71 MILES = IV-3 Shaly limestone Limestone Limestone and dolostone breccia Covered interval FicurE 2.-Diagrammatic sections showing generalized lithology of the McCann Hill Chert, Michelle Formation, and Prongs Creek Formation and positions of ostracode collections. Sections are arbitrarily arranged with reference to the top of the underlying Road River Formation, as determined by Churkin and Brabb in Alaska and Ludvigsen in Yukon Territory; overlying formations not shown. Adapted from Churkin and Brabb (1965, fig. 4, section 5), Fahraeus (1971, fig. 2), and Ludvigsen (1972, fig. 5). AGE AND CORRELATION The McCann Hill Chert and Michelle and Prongs Creek Formations contain a wide and varied fauna of invertebrates and vertebrates. Churkin and Brabb (1967) listed and illustrated some of the fossils from the McCann Hill Chert, and Churkin and Carter (1970) described the tentaculite fauna. In addition, Ormiston (1969) described a trilobite from the lower limestone and shale member of the McCann Hill Chert (USGS colln. 6492-SD). Ludvigsen (1970) discussed the fauna and illustrated brachio- pods and tentaculites from the Michelle Formation and later (Ludvigsen, 1972) described the dacryo- conarid tentaculites from the Michelle and Prongs Creek Formations. Stearn and Mehrota (1970) de- scribed the stromatoporoids of the Michelle and Prongs Creek Formations, Ormiston (1971) de- scribed the trilobites from the Michelle Formation, and Fahraeus (1971) described the conodonts from the Michelle and Prongs Creek Formations. The ages of the three formations have been assigned largely on the basis of the conodonts and the dacryoconarid tentaculites. The McCann Hill Chert fauna (USGS colln. 6492- SD) of ostracodes, bryozoans, trilobites, brachiopods, pelecypods, conodonts, and tentaculitids listed by Churkin and Brabb (1967, p. 2382-2833) was con- sidered by them to be Emsian (late Early Devonian) in age and to correlate with the upper part of the Salmontrout Limestone of the Porcupine-Salmon- trout Rivers area, Alaska. A probable late Emsian Age for USGS collection 6492-SD is suggested by the occurrence of the tentaculitid Nowakia barran- dei Boucek and Prantl, reported from this collection by Churkin and Carter (1970, p. 63), which, accord- AGE AND CORRELATION 5 ing to Boulek (1967, p. 1278), is typical of "upper- most Zlichovian or even of very basal Eifelian" beds in Bohemia. Huddle (in Ormiston, 1969, p. 1210- 1211) reported the late Emsian conodont Polygna- thus foveolatus Philip and Jackson from the same collection, and Klapper and others (1971, fig. 1) showed the basal McCann Hill as late Emsian and correlated it with the Blue Fiord Formation of Devon Island in the Canadian Arctic Archipelago and the upper Hurekaspirifer pinyonensis Zone of Nevada. Ormiston (1969, p. 1211-1212) considered the trilobite Koneprusia sp. from USGS collection 6492-SD to be most like K. subterarmate (Bar- rande) from the upper Emsian of the Harz region in Germany. In addition, USGS collection 6492-SD contains the two-holed crinoid ossicle Gasterocoma ? bicaula Johnson and Lane, which Johnson and Lane (1969, p. 70) considered late Emsian to Eifelian in age. Corals from the limestone and shale member of the McCann Hill which were considered Middle De- vonian by Oliver (in Churkin and Brabb, 1965, p. 181) do not come from the same localities as the ostracodes described here. The Michelle Formation fauna of brachiopods, tentaculites, nautiloids, trilobites, conodonts, and ostracodes was discussed and the brachiopods and tentaculites were illustrated by Ludvigsen (1970), who evaluated it as follows: (1) brachiopods indi- cate at least partial contemporaneity with those of the EHurekaspirifer pinyonensis Zone (Emsian) of Nevada; (2) the tentaculite fauna is tentatively cor- related with the Guerichina strangulata Zone of late Praguian (early Emsian) Age in Bohemia; (3) tri- lobites indicate an undifferentiated Emsian Age, with no forms indicative of the late Emsian; (4) conodonts indicate correlation with the Polygnathus lenzi fauna of early Emsian Age. This assessment indicates that the age of the Michelle Formation is Emsian and possibly early Emsian. Later, FAhracus (1971) described and illustrated the conodonts from Ludvigsen's collections from both the Michelle and Prongs Creek Formations. Fahraeus (1971, p. 670- 671) concluded that the Michelle collections were late early Emsian (late Praguian) in age, because of the presence of Polygnathus dehiscens Philip and Jackson, which he considered a senior synonym of P. lenzi Klapper. He noted that the highest collec- tion (V-5, fig. 2) from the Prongs Creek Formation on Solo Creek also contained P. dehiscens, implying a correlation between this part of the Prongs Creek and the Michelle. Ludvigsen (1972) described the dacryoconarid tentaculites from the Michelle and Prongs Creek Formations and concluded that they indicated an early Emsian Age, he cautioned (Lud- vigsen, 1972, p. 303), however, that a straightfor- ward correlation with the Bohemian succession can- not be made because of the overlapping teilzones in the Michelle of the Praguian tentaculite Turkesta- nella acuaria (Richter) and the Zlichovian Nowakia parabarrandei. An undifferentiated Emsian Age was suggested by House (in House and Pedder, 1963, p. 508) for the goniatite Teicherticeras lenzi from beds later in- cluded by Norris (1967b, p. 759) in the Michelle Formation. The two-holed crinoid ossicle Gastero- coma? bicaula of late Emsian to Eifelian Age, which occurs in the limestone and shale member of the Mc- Cann Hill Chert, has also been reported from the Prongs Creek Formation (Norris, 1967b, p. 770) and the Michelle Formation (Ludvigsen, 1970, p. 427) but also occurs abundantly in the overlying Ogilvie Formation (Norris, 19676, p. 773). In summary, previously described fossils suggest that the limestone and shale member of the McCann Hill Chert, the Michelle Formation, and the Prongs Creek Formation are all Emsian in age. Conodonts and dacryoconarid tentaculites indicate that Chur- kin and Brabb's collections from the limestone and shale member of the McCann Hill are late Emsian and that Ludvigsen's collections from the Michelle and Prongs Creek are early Emsian. The silicified ostracodes obtained by Churkin and Brabb are from five collections from the limestone and shale member in the type area of the McCann Hill Chert; two collections from the measured see- tion are about 10 feet apart stratigraphically and about 140 to 150 feet above the base of the forma- tion. Those obtained by Ludvigsen are from (1) six collections from the Michelle Formation, four of which, from one locality on the east side of the Blackstone River (Ludvigsen collections II-10 to 14, fig. 2), span a stratigraphic thickness of about 175 feet, starting about 300 feet above the base of the formation; and (2) three collections from the Prongs Creek Formation on Solo Creek which span a stratigraphic interval of about 140 feet, starting about 150 feet above the base of the formation. The ostracode taxa described in this paper and the col- lections in which they occur are listed in table 1. Of the 73 ostracode taxa listed in table 1, 51 have been found in the collections from the McCann Hill Chert, 28 in the collections from the Prongs Creek Formation, and 17 in collections from the Michelle Formation. Of the total number, 18 are represented by only 1 specimen and are therefore not significant for correlation between the formations; 6 of these 6 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY TABLE 1.-Ostracode taxa described in this paper and the formations and collections in which they occur Collections Ostracodes McCann Hill Michelle Prongs Creek A A A A A § 4 2 ¢ {lls a 9 a's $ )f E f mJ} 1 14s i116 f f 2 BSD . .. -.. - 1. 2 in 22 - o se oe ma on ne ae w w ne ne an ae he s hn an an e os s onn he oe me e so un Se ie edes ei e ea has ham | min reece ol i aie tive sel papi a oe ne oo Treposelia borealis 11, $$. _n = eu nolo olo oo neo oo ne a a ao oe a oe ne i me m me mme mome me e $4. M axl z --.! =- lanl he es | MC. oo Thea T reposella sp. cf. T. lyoni (Ulrich) ___.___________________ sathish bui ® o Lettuces oal ust Tet lec Beyrichin (Beyrichiny brabbi n. sp _______________________ Xx |X - X os sulla. Moll os (hoa tas o (Scabribeyrichiay churkini m. sp ____________LLLLLLLLL X | K Mill. Mile M" ul aalto (ok 2 L pode Yukonibeyrichina yukongngis "N. 8D Llc. X MX "Ke 22 KX Lull Kelle LLL - Ne - hk GOTO MZ PHD c. 222 .. 2 ca an oo ae at e te a ts oa te ae i us ae nl ot oe te I a os me e e e 'o m ma n be ce n ya" asl us awl l wal | ae ime | les | ime | tem o wig ol An | Reto Alaskabolbina unilinedt@ H. SD A\ <= Cas an ml | am imen | as iew oen e al on Aae os Weili Ts SD . _ -.. os 22 ltl PL cel n Heed he Salal a mo mien hn i ne ml ie ce oe me ss m ae have ba he ae lus . te (Ze ~al les M ._ c=lllen ) med on "Th. HD | -.. . _ cone o cll oo nl lies be li an ne ne hn es ms Sion nees me me se 'e fe ue ue ae an sal (Rel: fel! aul fas 1) wall we men lek! Shes Lok ma es BD S H 5 elie ce me ta ne e s ae on t ma m ar e a a e usd ot on yd on su os . mn s u os n im n s ian ml St e h in oe oad se has ii o hare o Aoi ast has t Nene | am io wean amet has ons - acl ante A AD (t c ce ce a arine ce me r sa one se or lam ne me e o r e he us he ts ue No ju an e A h m , i me in e me me s ne oe o an ce (wan MK) sel os) seliee like mew Opitvites bICOTRIS M. SD aelljes) a= leu. eel [us. we) se ums" Iss ae TN us [ee CI@USG N. 8D XK X (X T eu, salen iew] eer eal aw iet Nae mel 2 2 c ss ss ao oo cl co ne nn e. oe nl ne ne he ha ae ne Hl e na red ht te ie hn oa ne h n is onne i m an me me ie it an oe ! Cap CAO M. MIke ew ge sp ew ea (wa: am Wok | SD . =... .. - .. .. =. - wise < sec. me a pr n in ran an uo ne he ue n las s an e oe an me me oe n os an n! 'an l as: Gel mol | M (es | os" aml melon] hel hame. ece TOL _ SP . > + an - sl no cnl shal bn cll ele an Sain ute un U an an ma el at t e an in be ue me a s ae on bu n oe oul on d ie as Caw uh an | wellas eel aw asl ies (ae | PR elites Pailstpollex? mulligpinogit® Ti. BD X M\ as us eol Tun =| aul imo law / au Wink Hollinelia dudvigsent IN. SD X) Ce los" eu ar | ao | ae [PX he ea PaucitubererIidt@ N. SD in | an ew tine mell ae! fas 1 Rr Nn thls cu Abortivelum A., SD sell Ml LE Sou bel fron haw b anl fe I ak o ee 1 Naw , | nee hie Adeilphobolbinu GAHGUAORELE H. X - $. % M. cel Keune i aet ProOngsengis N.) SD . odie eae ams as . Cal led em' oul The fi awl as c ae, haw s hw l on -b as sp. cf. A: mediglis BEOVEP LLL. nur ww X X [uso L_) cl lise tus tes Sul OU P TOC FATE ALT ! SMD. .s so -o 21 c- s al ae se ca nn Ge aa an o ae at mean o u e ne mn ad an ht h e an be e a i pe hn e e e fe am an nel anl NPK P tee esl uel esis thos , o aged Infractivelum @CUMERGOREAM H. BD oe laa uel Co | onll ae! ae esl aml lins MC o Moe Ti.. SD L. o cl n oe. a e Noel o n hoon ot he e me tof e t me A oe he mene hn he ae e e s KX al Mx Lin ul ae s | ua an ress Al eee i ae Aae Chironiptrum rEHICUIAPIG N. 8D sml NY Cup uw . oal |M (es) A (ues hel es IS M. > SD . - e aoe se an e m oo an ae un an e aa e al hn t hn ml Re te e te e ne nnd i e Ar ne ne ue X ":X X X_ XML.l LL a. 1M. L2 es ObOHPIEIQ T N BPD " -.. .. 2. nl o. nn mn l cl on ma e an in ae on ae n n an at o t n oa Bl n i mn hrn r i ae iu bn ue u se . os pac M ul RL Cr IB LO Kirkbyelia (Kirkbyell@). 8D se ike e TLA [e" aul eu ies Nas (Esl age HmEQris 1, #D -- -- -m o ollo hn be m nene he ne e mone he he on ho ae he i me mee ae eve ou. =a lew (as -s | me' as) owl mel me:" asil ot) O l ons - Tr. BD . 24 cnl Ll ne al an ae al he Ta od cn a ae on he me te ne r oe e l ie to me he ne tn oe an he t e e ie X X. X® X) XD [SQ LA WC : T, SD -. - 2 ee 2 ee heal coe 62 on on et on nh He e m Be t nh te ta h oe sna ou h Sa 'd he se we is x X (MX X XLILMu L. Le | esl ian Subarctichites SETPOVIHIUS M. BD l K. r\ rM OML LL [L2 al ue Nested sal n be ad Libumella sp. cf. L. discoides Rozhdestvenskaya ___________ X! X . Ml lc '< ws «ul as aut | ork IMO be sp. cf, L. circulate Rozhdestvenskaya _________________ i \ it sa es Alliss bis tol l et Neoaparchites? sp. aff. N.? insericus (Rozhdestvenskaya) ____ X M L2 ls co L. 100 La P0 "Aparchites" sp. aff. "A." auriculiferus Rozhdestvenskaya __ sul Ko ligs as eu ast es! us uue cies ule a Buklocdenella Peete T1. SD . -. . .. : 2 s sul oo mene nle a als ae me nels he me ue me cem t ae tie in os wal MAM. X . X L2 wou te, "LLL aC SOlOCREIE M; | SD \ .... ..o s 2 oo ull nne L seen ne He te tr a th tn ae e hn ce u aa oe m a inte ar ie inne tel ai oh Lae sal -s Nies) celts (ime LR. i wa Mew Poloniella (Framella) sp. aff. P. (F.) scheii Weyant _______. al e o tM t La 1 as oe i Le gs o ue ies i e Alok Bairdia sp. cf. B. leguminoides Ulrich __._____L____._______ Lame K cL M XLI al. Al aw "ass . Aol S ne deféebo "h. Sp . . _o 2 onn ee el on u nel ee to He to oe an oe ne a he ar rene hae oe hr me h te in he ae sal ae as 9 ue I aa tes ae a ae hi ae as I asta au tes . SD \_. oc ll cl cool he m ela nel oe en arte an h h n he he e me us at Ga ht ue care e on Bo he e oe ms KX) uu tin Tes lea leslie" es) ews me | > i hak Pairdiolites?. SORRM IA.. SD X [ LZ tuu oM) outles ae es tew los) a" we NEWSOIMINERT BD -. .. .. l.. c ul 2 conn Hee alice ul no nline me th ie he bte an sa het ay N nme ne mt ut oe He me e m a wa) ean est Mt new The ae ae law i me (Le hee SD. - _ - _ s= -c aln a men on ne hele Palme es ue | er oe me hlee me me on me ne eate te se sel e o wen al uu Ls) eal ae. ewiuce faw. ew Alge yuROnensig M. SD nel Salsa les In [me ae am . hell the (les Mo O O pcg *! #D. .. .. . .. cl ln oo ole be ne m ue Ge me me ad we wn pe m ln s oe he mafic to s un at ha me m to ba in me me as sl K n Lu t ics hes e (as mes ute BD - -- .. . -- 2 n c m o a rel ee ce me ue o ne ar te te t un at he ma aoe r tn ae Ht ts on i he m na e as l a e e TM e Nia ies ee i aw t as en mln dias O ane COUTHAINM I, SD ch alee eb aa Tas ask. ue. eaten us (ine conics TT ESD .. = -» = .. so -- a oo oe me oe ne s me ur om me mt m ae Hin e e ar on oe me ay i son au m a an ie he b e oe he se se o L Ls it uas ao tl a l o NL s B SBD . 2 2. 2 2 e cl col co nl t nl ie cl he de e ne o os te he ae f as wn un nt we fas nu h oe me n mn ms nt am ne se he is X Mas. KX Mk. __ hele, ins w (ao Berounella sp. aff. B. minuta Blumenstengel _______________ aaa ait uy | ulan hks lee ves ms (as el (as Bairdiocypris? sp. cf. B.? cordiformis Rozhdestvenskaya ___ Lela eg tk i la us | wal as dies ties a irak BATTAROCIDIIE #T _ .... .. -- l nel Ele sena ae ae N m n me oa hs hn i cn ne ht yale al an n s oe ue an am we at salen he Pues w e LI TEL jar. (uma well wellies alone PCuresaaria biackstonensis N,. SD x '» x_x XIX _. x~ x ' Bairdiohealdites? seapulatus N. #D % % \% L2{La le Lous s o Leto Praepilatina sp. aff. P. praepilata sibirica Polenova _________ ae oie Sa i M M {was ae ! am i aalto ae (hes tal ae Baryehilind * Sp . .... . .. . c. 2 eee onl one 2 ue tl ote alos re ne e ae thoe as oe t an at nd at m We ma un me in sink! ( wel hale ake: | lake Have am a eal Lake i as tt ae Hice Trypetend 2 USD . ._. .. .. .... - .. o. us ulna m t ne al bl heme me od hth os me on ne fand an me S e ne me e as h oe ue ae he nell an am oie o am ieee a R ean ae sats | tas rre t one AGE AND CORRELATION T TABLE 1.-Ostracode taxa described in this paper and the formations and collections in which they occur-Continued Collections Ostracodes McCann Hill Michelle Prongs Creek A o a a a i E i if i 5 92 A ® 5 co 0 p s 886 sof b ¢ f 1 : a /f f ¢ Voronina sp. cf. V. inventa Rozhdestvenskaya ______________ N UX L Lei ce he law! hell mall a. mm c mwall ae a oa ties Cavellina (Invisibil@) ? SD nne e ies! as t ae ae os aw ies t was tes ie te ub HIDOUPATC ANTS !; .. .. .. ... !. - 2. s io wl oo tn nene os ml nat as t i'm mla e he h hl nd ne H s me on n me an X uUX X OX ks) wall bn ee dae PR. ae. Hara indet, 1 -e sn eens cen s X 'X -' X s Ls" A2 Lud tee aril oe, me mies Pachydomeallid indet. 2 ..._.__....._._____________L__L___L ail he het M ae aa ulan i an as ett O et T 2 AST ) o n e an ce ao n a 2 a ao he tar o on mnt h mn an d ma in e l an he on e he he an ap rh na me in b car a an ~- ies as MIE 12k es am an es B Tew . uel ew Neocraterellina? erescentifera n. sp ______________________ X M M OX alles illus mol cin PO e SD -. -- -- - ~- - - - -. ca - - n - m nne ne he tinne he is an rane mn ef on Ee he in e mel e-" an) anl bal thw |. wel poul! mellierw imal 1 PX a ee alan Ostracode Andet. 1 sun ce tk n asm s as t as as i he e l ani tes ies i ha res tt P9 M e Aas ian Ostracode AMACL. 2 .... .._ > .. 2 2. _.... _. oo ol ol cl nne nnn n hone a wale nee ane e mene in he K : we l lL. eo ilies wel es oe gall Lull So Rp Ostracode MACK, 9 heli he os nh os (ee ks armies s aw Ai uw n 9. ( ae los rare specimens occur in the McCann Hill Chert, 6 in | of early Middle Devonian (Eifelian) age. All seven the Michelle Formation, and 6 in the Prongs Creek | genera listed above occur with Eifelian conodonts Formation. Three of the single specimens from the Michelle Formation are from Ludvigsen collection I-3, which is shown by Ludvigsen (1972, fig. 3) as being more than 200 feet below the other ostracode- bearing collections from the Michelle. Of the 22 sig- nificant taxa in the Prongs Creek, 13 also occur in the collections from the McCann Hill Chert, and of the 11 significant taxa in the Michelle, 8 also occur in the McCann Hill collections. The Michelle and Prongs Creek collections have five taxa in common. These figures include three species of beyrichiids which occur in all three formations. The ostracodes, as well as the other groups of fossils, therefore, sug- gest that at least part of the Michelle and Prongs Creek Formations and the limestone and shale mem- ber of the McCann Hill Chert are approximately the same age. For purposes of intercontinental correlation the ostracodes are of little assistance in confirming the age of the Michelle and Prongs Creek Formations and of the limestone and shale member of the Mc- Cann Hill Chert as determined by other groups of fossils. This is partly because most of the species are new, but also because at least seven of the genera have not hitherto been reported from beds older than Middle Devonian (Eifelian), and six have not been reported from beds younger than middle Early De- vonian (Siegenian). On a generic level, the most distinctive groups are the hollinaceans and the beyrichiaceans. The hollinacean genera Abditolocu- lina, Adelphobolbina, Falsipollex, Flaccivelum, Hol- lina, and Hollinella and the beyrichiacean Treposella would under other circumstances appear indicative (Huddle, oral commun., 1972) in collections from the Paraspirifer acuminatus Zone of the Jefferson- ville Limestone at the Falls of the Ohio between Jeffersonville, Ind., and Louisville, Ky.; the hollinids have been described by Kesling and Peterson (1958). None of them has been found in upper Lower De- vonian (Emsian) formations in eastern North America such as the Camden Chert (Bassler, 1941; Swain, 1953) or the Schoharie Formation (Berdan, 1971), nor have they been reported from formations of Emsian Age in the Rheinische Schiefergebirge (Groos and Jahnke, 1970; Stoltidis, 1971) or Ost- thiiringen (Zagora, 1968) in Germany, nor from Emsian formations in the Salair district of Siberia (Polenova, 1968). Other Middle Devonian elements in the fauna are the forms closely related to Voronina inventa Rozh- destvenskaya, 1962, Neogparchites? insericus (Rozh- destvenskaya, 1962), "Aparchites" auriculiferus Rozhdestvenskaya, 1962, Libumella discoides Rozh- destvenskaya, 1959, and Bairdiocypris? cordiformis Rozhdestvenskaya, 1959, all from beds considered to be Eifelian in Bashkiria, on the western slope of the Ural Mountains in the U.S.S.R. On the other hand, Early Devonian or older ele- ments of the fauna are represented by such genera as Mesomphalus, Beyrichia (Beyrichia), Beyrichia (Scabribeyrichia), Parabolbina, Newsomites, and Shidelerites. Beyrichia (Scabribeyrichia) and Shi- delerites have not previously been reported from strata younger than Silurian; the other genera range from the Silurian into the early or middle Early Devonian (Gedinnian or Siegenian) but have 8 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY not yet been reported from beds of Emsian Age. A form related to Praepilatina praepilata sibirica Pole- nova, 1970, from the upper Krekov beds in the Salair district of Siberia also suggests a Siegenian Age. The only Emsian element in the ostracode as- semblage is the form closely related to Poloniella (Framella) scheii Weyant, 1968, from the lower part of the Blue Fiord Formation on Ellesmere Island, as this part of the formation is considered late Emsian by Boucot, Johnson, and Talent (1969, pl. 20). Although the ostracodes from Alaska and Yukon Territory show little affinity with any described Em- sian ostracode fauna, late Early Devonian ostra- codes have been relatively little studied in compari- son with those from the Middle Devonian of the North American midcontinent region, Germany, Czechoslovakia, Poland, and Russia. Because the collections from which the ostracodes were obtained have been dated as Emsian on the basis of other groups of fossils, it is necessary to extend downward the ranges of at least seven genera not previously known below the Middle Devonian. The evidence from conodonts and dacryoconarid tentaculites that the McCann Hill collections are late Emsian and the Michelle and Prongs Creek collections are early Emsian suggests that many of the ostracodes de- scribed here have an undifferentiated Emsian range. This ostracode assemblage appears to represent a provincial fauna combining relict beyrichiaceans with ancestral hollinaceans and including elements that appeared later in widely separated areas. It will probably prove useful for Emsian correlation within the Arctic province. LIST OF LOCALITIES 1. McCann Hill Chert, lower limestone and shale member. USGS collection 6492-SD, one-half mile west of Hillard Peak, 3.4 miles N. 41° W. of Inter- national Boundary Commission monument 105, 64°57'3" N., 141°04'5" W., about 140 feet above base of McCann Hill Chert. USGS collection 70382- SD, same locality as above but about 10 feet stra- tigraphically higher. USGS collection 7033-SD, same locality as above, composite sample from float material. USGS collection 7037-SD, from thin beds of limestone conglomerate in shale se- quence, 300 feet east of USGS collection 6492-SD, 64°57'2" N., 141°4'9" W. USGS collection 7038- SD, same locality as above, 5 feet above USGS collection 7037-SD. All collections from Eagle (D-1) quadrangle, Alaska, made by E. E. Brabb, 1961, 1963. 2. Michelle Formation. GSC locality 86588, Lud- vigsen's sections II and III (fig. 2), east side of Blackstone River, 65°41.5 N., 137°26.55 W., Yu- kon Territory. Collections made by Rolf Ludvig- sen. II-10 ; 260 feet below top of Michelle Formation. II-11 ; 200 feet below top of Michelle Formation. II-13 ; 160 feet below top of Michelle Formation. II-14 ; 100 feet below top of Michelle Formation. 3. Michelle Formation. GSC locality 86589, Ludvig- sen's section IV (fig. 2), south-facing ridge ap- proximately halfway between Hart and Blackstone Rivers, 65°41' N., 137°01' W., Yukon Territory. Collections made by Rolf Ludvigsen. IV-3 ; 125 feet below top of Michelle Formation. 4. Michelle Formation. GSC locality 86587, Ludvig- sen's section I (fig. 2), west side of Hart River, 65°38.2' N., 136°44' W., Yukon Territory. Collec- tions made by Rolf Ludvigsen. I-3; about 75 feet above base of Michelle Formation. 5. Prongs Creek Formation. GSC locality 86590, Ludvigsen's section V (fig. 2), Solo Creek, 65°51.4' N., 134°15.5 W., Yukon Territory. Collections made by Rolf Ludvigsen. V-3 ; 161 feet above Monograptus yukonensis. V-4 ; 196 feet above M. yukonensis. V-5 ; 305 feet above M. yukonensis. SYSTEMATIC PALEONTOLOGY Suprageneric classification of the Class Ostracoda is based largely on the "Treatise on Invertebrate Paleontology-Part Q, Arthropoda 3," edited by Moore (1961), except for the family Beyrichiidae, which is classified according to Martinsson (1962), and the superfamily Hollinacea, which is adopted from Bless and Jordan (1971). The terms used for morphologic features are based partly on the "Trea- tise," except for the terminology used for the beyri- chiids, which follows that proposed by Martinsson (1962) and Henningsmoen (1965). Because this terminology is widely used by students of beyrichiids it seems desirable to use it here rather than to ad- here to that of the "Treatise" (1961) for the sake of consistency. All measurements of specimens were made with a micrometer ocular. Abbreviations used for institutions from which collection or specimen numbers are cited are as fol- lows: Geological Survey of Canada, GSC ; U.S. Geo- logical Survey, USGS; U.S. National Museum of Natural History, USNM. The section and collection numbers of Ludvigsen (1970) have been used to facilitate comparison with later papers by Fahraeus (1971) and Ludvigsen (1972). SYSTEMATIC PALEONTOLOGY 9 Order PALAEOCOPIDA Henningsmoen, 1953 Suborder BEYRICHICOPINA Scott, 1961 Superfamily BEYRICHIACEA Matthew, 1886 Family BEYRICHIIDAE Matthew, 1886 Subfamily CRASPEDOBOLBININAE Martinsson, 1962 Genus MESOMPHALUS Ulrich and Bassler, 1913 Mesomphalus? sp. Plate 1, figures 1, 2 ?Mesomphalus sp., Copeland in Ludvigsen, 1970, p. 426, 427. apparently subquadrate in lateral view ; hinge straight. Anterior cardinal angle about 105°. Anterior margin smoothly rounded; venter straight; posterior margin unknown. Great- est height and length unknown. Valve surface papillose, papillae of uniform size. Trilobate, anterior lobe weakly developed, extending feebly to dorsum, separated from preadductorial node by a very low prenodal sulcus; preadductorial node situated above midvalve and separated from syllobium by narrow, shallow, posteriorly convex adductorial sulcus. Syllobium unknown. Ventral part of valve dissected by obliquely curved longitudinal fissus extending from beneath preadductorial node posteriorly for unknown distance. Prominent velar ridge separated from domicilium by pronounced groove paralleling free margin; velar ridge sepa- rated from incomplete marginal ridge by narrow groove. Marginal ridge composed anteriorly and posteriorly of short denticles or spines, none ven- trally. Material.-Two incomplete teenomorphic valves. Measurements.-Length of figured specimen GSC 29438, 1.8 mm; height of figured specimen GSC 29439, 1.25 mm. Types.-Figured specimens, GSC 29438, 29439. Discussion.-These specimens appear somewhat similar to Mesomphalus hartleyi Ulrich and Bassler, 1913, as figured by Kesling and Rogers (1957, pl. 130, figs. 11-15). The marginal spines of the present specimens are more acuminate, and the preadduc- torial node apparently is in a more dorsal position. Without complete teecnomorphic and, more important, complete heteromorphic valves these specimens can- not be placed unequivocally within Mesomphalus. Martinsson (1962, p. 188-190) has indicated the similarity of the Devonian genus Mesomphalus to the Silurian genus Clintiella Martinsson, 1962. From the literature it appears, however, that differences exist between these genera based on velar and mar- ginal structures. Cruminal differentiation is un- known. Occurrence.-Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory. Subfamily TREPOSELLINAE Henningsmoen, 1954 Genus TREPOSELLA Ulrich and Bassler, 1908 Treposella borealis n. sp. Plate 1, figures 5-10 Treposella sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, figs. 16, 17. [Imprint 1967.]; Copeland in Ludvig- sen, 1970, p. 426. Description.-Lateral outline amplete to preplete. Preadductorial lobe outlined by shallow indistinet prenodal sulcus; adductorial sulcus deep, narrow, widest at ventral end. Syllobium cuspate; cusp pro- trudes above hinge line. Fissus on syllobium connects with prenodal sulcus to form groove concentric to free margin. Velar ridge distinct, extends completely around free margin. Surface reticulate except for velar ridge and adductorial sulcus. Crumina ventral, elongate ovate, very finely punctate. Velar edge crosses crumina with two treposelline bridges; in- terior of crumina with strut about middle of length. Material.-Fourteen specimens from Alaska, one specimen from Yukon. Measurements.-The holotype, a heteromorphic valve, measures 2.35 mm in length and 1.50 mm in height. A paratype tecnomorphic valve measures 2.25 mm in length and 1.43 mm in height. Types.-Holotype, USNM 170352; paratypes, USNM 170351, 173730, 173731, GSC 29453. Discussion.-Treposella borealis differs from T. lyoni (Ulrich, 1891), the type species of Treposella, in having a less prominently cuspate syllobium and in having a punctate rather than striate crumina. It differs from T. stellata Kesling, 1955, in having only one fissus across the syllobium and no crista on the crumina. The morphology of the ventral surface of the crumina of T. borealis resembles that of Gar- nielle Martinsson, 1962, as illustrated by Martinsson (1962, text fig. 89B). The dolonoid sear of Treposella lyoni, described by Martinsson (1962, p. 211-214) from the illustrations of Kesling and Rogers (1957, pl. 127, fig. 3), has not been observed on our speci- mens of T. borealis. collections 6492-SD, 7082- SD, 7033-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collection V-3, from the Prongs Creek Formation, Solo Creek, Yukon Territory. Treposella sp. cf. T. lyoni (Ulrich, 1891) Plate 1, figures 3, 4 Discussion. -Two small teenomorphic specimens with the lobation of Treposella lyon; (Ulrich, 1891) and coarser reticulation than T. borealis n. sp. have been found in the McCann Hill Chert. These speci- mens have the cuspate, vertically divided syllobium v 10 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY of T. lyoni but differ from that species in having a very reduced velar ridge. Because the only two speci- mens found are probably immature individuals, an unequivocal specific assignment is not possible. Measurements.-The figured specimen (pl. 1, fig. 3) is 0.75 mm long and 0.45 mm high. Types.-Figured specimens, USNM 173728, 173729. Occurrence.-USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Subfamily BEYRICHIINAE Matthew, 1886 Genus BEYRICHIA M'Coy, 1846 Subgenus BEYRICHIA M'Coy, 1946 Beyrichia (Beyrichia) brabbi n. sp. Plate 2, figures 1-8 Beyrichia (Beyrichia) sp. A, Berdan in Churkin and Brabb, 1968, table 1, pl. 4, figs. 11, 12. [Imprint 1967.1]; Cope- land in Ludvigsen, 1970, p. 426, 427. Description.-Lateral outline preplete to amplete. Anterior lobe broad; prenodal sulcus distinct, in- clined posteriorly and tending to isolate pyriform preadductorial lobe. Adductorial sulcus deep, curved anteriorly, extending half or more than half height of valve. Syllobium broad, undivided. Anterior cusp developed as spine; two posterodorsal spinose cusps on syllobium, widely separated, diverging at angle of about 40°. Velar ridge distinct, spinose. Surface covered with spines or pustules except for sulci and small field dorsal to adductorial sulcus, preadduc- torial lobe, and prenodal sulcus, in which are only two small spines, one dorsal to adductorial sulcus and one dorsal to preadductorial lobe. Finely granu- lose ornamentation superimposed on pustulose orna- mentation. Crumina of heteromorph large, ovate, anteroventral, distinctly set off from domicilium, bounded posteriorly by adductorial sulcus. Ornamen- tation of crumina like that of domicilium except that pustules are smaller on ventral surface. Trace of velar ridge across ventral surface of crumina indi- cated by row of small pustules or spines. Material.-More than 40 specimens from the Mc- Cann Hill Chert, more than 3 specimens from the Michelle Formation, and more than 6 specimens from the Prongs Creek Formation. Measurements.-The holotype, a heteromorphic right valve, measures 2.6 mm in length and 1.5 mm in height. A tecnomorphic right valve, a paratype, measures 2.5 mm in length and 1.5 mm in height. Measurements of 27 specimens from the McCann Hill Chert (USGS colln. 6492-SD) are shown in figure 8. Types.-Holotype, USNM 170346; paratypes, USNM 170347, 173782, 1783788, 178784, 178785, 173786, GSC 29478, 29474. Discussion.-This species is similar to Beyrichia (Beyrichia) arctigena Martinsson, 1960 in its undi- vided syllobium, the size and position of the cru- mina, and the presence of the two small spines above the adductorial sulcus and preadductorial lobe. How- ever, unlike Beyrichia (Beyrichia) brabbi, B. (B.) arctigena is only very sparsely pustulose. In addi- tion, the syllobial cusps of B. (B.) arctigena are closer together than those of B. (B.) brabbi. Both species differ from all other species assigned to Beyrichia in having undivided syllobia (Martinsson, 1960, p. 17). The species is named for Earl E. Brabb of the U.S. Geological Survey, who collected the first specimens. Occurrence.-USGS collections 6492-SD, 7032- SD, 70383-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collection II-11 from the Michelle Formation, Blackstone River, Yukon Territory; Ludvigsen collections V-3 and V-4, from the Prongs Creek Formation, Solo Creek, Yukon Territory. Subgenus SCABRIBEYRICHIA Martinsson, 1962 Beyrichia (Scabribeyrichia) churkini n. sp. Plate 3, figures 1-9 Beyrichia (Beyrichia) sp. B, Berdan in Churkin and Brabb, 1968, table 1, pl. 4, figs. 13, 14. [Imprint 1967.]; Cope- land in Ludvigsen, 1970, p. 426, 427. Description.-Lateral outline preplete to amplete. Anterior lobe broad; prenodal sulcus narrow, dis- tinct, curved posteriorly beneath preadductorial lobe. Preadductorial lobe subpyriform, slanted posteri- orly; adductorial sulcus wide, extending about half height of valve. Syllobium wide, divided by sinuate curving fissus or syllobial groove which joins pre- nodal sulcus beneath adductorial sulcus and pread- ductorial lobe at angle of approximately 90°. Velar ridge narrow, spinose. Anterior lobe cuspate; two closely spaced spinose cusps on syllobium. Entire surface except for sulci covered with closely spaced, prominent tubercles, four of which tend to merge to form calcarine spine. Crumina large, ovate, antero- ventral, pustulose. Tubercles on ventral surface of crumina not markedly different from those on domi- cilium except for row of small tubercles marking trace of velar ridge. Material.-More than 60 specimens from the Mc- Cann Hill Chert; more than 15 specimens from the Michelle Formation; more than 30 specimens from the Prongs Creek Formation. Measurements.-The holotype, a heteromorphic left valve, is 2.80 mm long and 1.55 mm high. A paratype tecnomorphic left valve is 2.60 mm long SYSTEMATIC PALEONTOLOGY , 11 2.0 I I I EXPLANATION f :g Tecnomorphic specimen h CC w 9 i- - { 9 9 g 1.5 |- Heteromorphic specimen O -I S o g af = © o_ a.? 3 Two specimens with o bd z identical measurements @e * al 0 iw O L ee = o § 1.0 - - x o e ceo % e o 0.5 | ] | | 0.5 1.0 1.5 2.0 2.5 3.0 MAXIMUM LENGTH, IN MILLIMETERS FigurE 3.-Scatter diagram of maximum length versus maximum height for Beyrichia (Beyrichia) brabbi n. sp.; 27 spe- cimens from the McCann Hill Chert (USGS colin. 6492-SD, paratype slide USNM 173735). and 1.55 mm high. Measurements of 57 specimens from the McCann Hill Chert are shown in figure 4. Types.-Holotype, USNM 170349; paratypes, USNM 170348, 173737, 173738, 173739, GSC 29469, 29470, 29471, 29472. Discussion.-This species is here placed in the subgenus Scabribeyrichia Martinsson, 1962, because of the characteristic zygal arch outlined by the junc- tion of the fissus or syllobial groove with the pre- nodal sulcus. Although it superficially resembles species of Hobeyrichia Henningsmoen, 1954, as illus- trated by Henningsmoen (1954, p. 21, pl. 1), Hobey- richia has a fissus on the anterior lobe as well as on the syllobium. Beyrichia (Scabribeyrichia) churkini resembles the form described by Martinsson (1962, p. 301-302, fig. 165B, 1650) as Beyrichia (aff. Sca- bribeyrichia) sp., from the Wenlock of Gotland, but the North American species has a narrower, more distinct fissus and sharper cusps. It differs from other described species of Seabribeyrichia, such as Beyrichia (Scabribeyrichia) foliosa (Jones, 1888), in being more pustulose. This species is named for Michael Churkin, Jr., who has collected and studied the McCann Hill Chert fauna. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7038-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collection II-11, Michelle Formation, Blackstone River, Yukon Territory; Ludvigsen collections V-3, V-5, Prongs Creek Formation, Solo Creek, Yukon Territory. Genus YUKONIBEYRICHIA n. gen. Type species.-Yukonibeyrichia yukonensis n. sp. Species included.-Yukonibeyrichia solo n. sp. Diagnosis.-Beyrichiine ostracodes with wide, flattened anterior supravelar field sharply set off from remainder of domicilium. Prenodal sulcus weak to obsolete so that anterior lobe and preadductorial lobe tend to merge. Adductorial sulcus wide and deep. Syllobium with single cusp, with or without fissus. Crumina of heteromorph inflates and obliter- ates anterior supravelar field and occupies antero- ventral part of domicilium up to prenodal sulcus. Ornamentation pustulose. Discussion.-The lobation of this distinctive genus superficially resembles that of a hollinid rather than a beyrichiid, but the cruminal dimorph- 12 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY Fs T I T T e EXPLANATION Q % w ® e e CC Tecnomorphic specimen to o m t- o s $ 18 d & 3 Heteromorphic specimen o ra *,°° 3 @ o £ Two specimens with &. identical measurements @ 3 0 0 o & o d o J e ee o o 3 ) 4g" _ & a §o x * '% <4 @ o 3 e 6e ce o e 8 | | | 1 0.5 0.5 1.0 1.5 2.0 2.5 3.0 MAXIMUM LENGTH, IN MILLIMETERS FIGURE 4.-Scatter diagram of maximum length versus maximum height for Beyrichia (Scabribeyrichia) churkini n. sp.; 57 specimens from the McCann Hill Chert (USGS coll. 6492-SD, paratype slide USNM 1737839). ism indicates that it belongs with the latter group. It is apparently a late development of the line of Beyrichia s. s. The generic name is derived from Yukon Territory and the Yukon River area where it is found. Geologic range.-As yet this genus is known only from the Lower Devonian of Alaska and Yukon Ter- ritory. Yukonibeyrichia yukonensis n. sp. Plate 4, figures 5-11 Beyrichiid, n. gen., n. sp., Berdan in Churkin and Brabb, 1968, pl. 4, fig. 10. [Imprint 1967.] Description.-Lateral outline preplete; dorsal margin straight; anterior cardinal angle distinct; anterior margin curved smoothly into gently curved ventral margin; posterior margin gently curved; posterior cardinal angle more acute than anterior angle. Wide supravelar field extends anterodorsally around anterior lobe and preadductorial lobe to ad- ductorial sulcus. Prenodal sulcus weak; preadduc- torial lobe pyriform, only slightly separated from small arcuate anterior lobe. Adductorial sulcus wide and deep. Syllobium large, with shallow fissus. An- terior cardinal angle cuspate; anterodorsal cusp on supravelar field dorsal to prenodal sulcus. Dorsal tubercle on cusp on syllobium; uncular tubercle on posterior supravelar field below posterior cardinal - angle. Small tubercle near dorsum above adductorial sulcus. Supravelar field granulose to weakly papil- lose; remainder of domicilium strongly pustulose except for sulci and fissus. Crumina pustulose like domicilium. Velar ridge apparently crosses ventral surface of crumina without deflection. Material.-Twenty-three valves from the McCann Hill Chert; more than three specimens from the Mi- chelle Formation ; more than 20 specimens from the Prongs Creek Formation. Measurements.-The holotype, a large tecnomor- phic left valve, is 2.80 mm long and 1.60 mm high. Another tecnomorphic left valve (USNM 173742) from the McCann Hill Chert is 2.60 mm long and 1.35 mm high. Measurements of 20 specimens from the McCann Hill Chert are shown in figure 5. Types.-Holotype, GSC 29432, paratypes, GSC 29433, 29434, USNM 170345, 173740, 1783741, 178742, 1783748, 1783744. Discussion.-This species is characterized by its pustulose surface and prominent anterodorsal cusp. SYSTEMATIC PALEONTOLOGY 3B 1.5 | EXPLANATION @ i USGS colin. 6492-SD G A i- a @ g USGS colin. 7032-SD E A § A € @ T 1.0 |- A © fk '_ 0 % A © Me] g A 3 @ 2 s 3 @ PY3 @ As % @ 0.5 I I | "0.5 1.0 1.5 2.0 2.5 MAXIMUM LENGTH, IN MILLIMETERS FicurE 5.-Scatter diagram of maximum length versus maximum height for Yukonibeyrichia yukonensis n. sp.; 20 speci- mens from the McCann Hill Chert (USGS colln. 6492-SD, paratype slide USNM 173748; USGS colln. 7032-SD, para- type slide USNM 173744). The uncular tubercle is also characteristic, although there is some variation in its relative size. The posi- tion of the uncular and other tubercles appears to be constant throughout the ontogeny of the species, but it is more prominent on immature specimens and better developed on specimens from the Mc- Cann Hill Chert than on specimens from the Prongs Creek Formation. The name of the species is based on its occurrence in the Yukon River Valley and- Yukon Territory. Occurrence.-USGS collections 6492-SD, 708382- SD, 7033-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collections II-11, II-14, from the Michelle Formation, Black- stone River, Yukon Territory ; Ludvigsen collections V-3, V-4, V-5, from the Prongs Creek Formation, Solo Creek, Yukon Territory. Yukonibeyrichia solo n. sp. Plate 4, figures 1-4 Description. outline preplete; anterior cardinal angle distinct. Anterior margin curved smoothly into gently curved ventral margin; poste- rior margin smoothly curved. Supravelar field wide anterodorsally, extends dorsally around end of an- terior and preadductorial lobes to adductorial sulcus. No cusps or prominent tubercles on supravelar field. Prenodal sulcus obsolete, so that anterior and pread- ductorial lobes are fused. Adductorial sulcus wide and deep. Syllobium lacking fissus; syllobium has one blunt cusp which lacks prominent tubercle. Sur- face of domicilium with low pustules except for supravelar field, which is granulose. Crumina pustu- lose like domicilium; velar ridge appears to cross ventral surface of crumina as slightly sinuous line. Antrum or groove between velar ridge and marginal ridge partly constricted beneath crumina. Material.-Three specimens from the Prongs Creek Formation. Measurements.-The holotype, a tecnomorphic right valve, is 2.30 mm long and 1.30 mm high. Para- type GSC 29436, a carapace, is 2.20 mm long and 1.30 mm high. Types.-Holotype, GSC 29485; paratypes, GSC 29436, 29437. Discussion. -Y solo differs from Y. yukonensis in the complete obsolescence of the pre- nodal sulcus, the lack of a fissus on the syllobium, and especially in the lack of the anterodorsal cusp, the uncular tubercle, and the tubercle above the ad- ductorial sulcus. Although only three specimens have been found, the consistent character of the cusps and tubercles in several instars of Y. yukonensis sug- gests that the specimens lacking the anterodorsal 14 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY cusp belong to a distinct and different species. The name of the species is derived from Solo Creek, Yukon Territory. Occurrence.-Ludvigsen collections V-3 and V-4, Prongs Creek Formation, Solo Creek, Yukon Terri- tory. Subfamily indet. Genus ALASKABOLBINA n. gen. Type species.-Alaskabolbina unilineata n. sp. Species included.-Alaskabolbina bilineata n. sp., Alaskabolbina nodilineata n. sp. Diagnosis.-Nonsuleate paleocope ostracodes with central bulb or node and with anterodorsal and pos- terodorsal cusps or spines. Velum tubulous, incom- plete, extending from anterior cardinal angle to posteroventral slope, ending in hollow spine. Domi- ciliar ornamentation pustulose. Ridge or ridges (torus?) on subvelar field parallel to free margin. Heteromorph not known. Discussion.-The tubulous velum of Alaskabolbina suggests beyrichiid or eurychilinid affinities, but until heteromorphs are found, the systematic posi- tion and relationship of this genus cannot be deter- mined. The conspicuous bulb, which occupies the position of the median suleus in other ostracodes, is similar to that of the Late Ordovician chilobolbinid genus Cystomatochilina Jaanusson, 1957, but Alas- kabolbina lacks any trace of a median pit, and the velum does not extend around the entire free mar- gin. Alaskabolbina may be related to the nonsulcate craspedobolbinine genera Apatobolbina Ulrich and Bassler, 1923, Leptobolbina Martinsson, 1962, and Schohariello Berdan, 1971, but these genera lack the median bulb. The name of the genus is derived from its occurrence in Alaska combined with -bolbina, in reference to the characteristic median swelling. Geologic range.-As yet this genus is known only from the Lower Devonian of Alaska and Yukon Territory. Alaskabolbina unilineata n. sp. Plate 5, figures 13-15 Description. -Lateral outline amplete to slightly preplete. Large subcircular median node above mid- height of valve. Median node verrucose, subconical in profile. Massive blunt verrucose anterodorsal and posterodorsal cusps protrude above hinge line. Sur- face finely papillose, with scattered tubercles ar- ranged concentrically around median node; one large tubercle above node and between two dorsal cusps. Striated velum extending from anterodorsal angle to posterior part of free margin, ending in upward recurved spur. Velum curved 'away from contact margin in ventral view; subvelar field crossed by single finely denticulate toric ridge parallel to free margin. Heteromorph not known. Material.-One right valve, and a few fragments from the McCann Hill Chert. Measurements.-The holotype and only specimen is 1.70 mm long and 0.90 mm high. Types.-Holotype, USNM 178745. Discussion. only one relatively com- plete specimen of this species has as yet been found, it is so distinctive that a specific name seems justi- fied. It differs from other species of Alaskabolbina in having heavier dorsal cusps, a single toric ridge, and in being more sparsely papillose. collection 6492-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Alaskabolbina bilineata n. sp. Plate 5, figures 16-21 Description.-Lateral outline amplete. Valve non- sulcate, with large subcircular median node at or slightly above center of valve. Domicilium cuspate at both ends; cusps spinose, extending above dorsal margin. Surface papillose, with scattered tubercles surrounding central node and distributed over valve surface. Striated velum extending from anterodorsal angle (?) to posterior part of free margin, ending in tubulous spur. In ventral view, velum bowed out- ward near midvalve, in contact anteriorly and pos- teriorly with double torus; toric ridges parallel to and at some distance from marginal ridge. Material.-Five specimens from the Michelle For- mation. Measurements.-The holotype is 1.80 mm long and 1.00 mm high. Types.-Holotype, GSC 29464; paratypes, GSC 28465, 29466, 29467, 29468. Discussion.-This species differs from Alaskabol- bina unilineata, the type species, in having spinose rather than nodose dorsal cusps, more tubercles on the surface of the valve and double subvelar toric ridges rather than a single denticulate torus. Occurrence.-Ludvigsen collection II-11, from the Michelle Formation, Blackstone River, Yukon Terri- tory. Alaskabolbina nodilineata n. sp. Plate 5, figures 1-6 Description.-Lateral outline amplete. Valves non- sulcate, with large subcirecular median node above center of valve. Valves with wide anterior extralo- SYSTEMATIC PALEONTOLOGY 15 bate area. Valves with larger tubercles in position of cusps, extending above dorsal margin. Surface papil- lose with numerous scattered tubercles surrounding and encroaching on median node, extra-lobate area with few tubercles. Striated velum extending from midanterior to posterior part of free margin, end- ing in spur. In ventral view, velum bowed outward near midvalve, with subvelar area convex and tra- versed by double row of tubercles (torus?) parallel with free margin. Interior with deep impressions of central node and anteroventral lobe reminiscent of crumina. Material.-Two specimens from Prongs Creek Formation. Measurements.-The holotype is 1.20 mm long and 0.60 mm high. Types.-Holotype, GSC 29512; paratype, GSC 29518. Discussion.-This species differs from Alaskabol- bina unilineata in having a large anterior extra- lobate area, in being more pustulose, and in having a double row of subvelar tubercles as a toric struc- ture in the position of the single denticulate torus of A. unilineata. It differs from A. bilineata in hav- ing a large anterior extralobate area, in being more pustulose, and in having a double row of subvelar tubercles instead of a double ridge as in A. bilineata. The two valves which represent this species may be heteromorphic, but this is not certain. The ventral obesity of the specimens in lateral view, the convex nature of the subvelar field and the depth of the ventral lobate area in interior view suggest this pos- sibility. However, they are not heteromorphs of either Alaskabolbina unilineata or A. bilineata be- cause of the differences in the character of the orna- mentation. Occurrence.-Ludvigsen collection V-3 from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. Alaskabolbina sp. Plate 5, figures 11, 12 Discussion.-Two small specimens (USNM 173844, 173845) from the McCann Hill Chert (USGS colln. 7037-SD) are apparently immature tecno- morphs of a species of Alaskabolbina. They have the prominent dorsal cusps and median bulb character- istic of the genus, but the velum of both specimens is relatively short and the torus is poorly developed, making it impossible to assign them to any of the described species. The flaring velum of the larger specimen (USNM 173845, pl. 5, fig. 12) is like that of A. nodilineata n. sp., but the dorsal cusps are not as well developed in that species. The smaller speci- men is 0.55 mm long and 0.30 mm high; the larger specimen is 0.80 mm long and 0.40 mm high. Alaskabolbina? sp. Plate 5, figures 7-10 Discussion.-Four small specimens which appear to be related to Alaskabolbina have been found in the McCann Hill Chert (USGS colln. 7037-SD). These have the median bulb of Alaskabolbina, but lack dor- sal cusps and are less papillose than any of the spe- cies here assigned to the genus. Two of the figured specimens, USNM 173840 (pl. 5, fig. 7) and USNM 173841 (pl. 5, fig. 8), have short vela which are bent almost perpendicularly to the plane of commissure; one, USNM 173842 (pl. 5, fig. 9), which is otherwise similar, has a longer and less recurved velum. The fourth figured specimen, USNM 173843 (pl. 5, fig. 10), has a short but not recurved velum and is more papillose than the others. These specimens are prob- ably immature forms of two or more species of which the adults are as yet unknown. The material is not adequate for a formal description, but is illus- trated here to show the variety of the ostracode fauna. Superfamily DREPANELLACEA Ulrich and Bassler, 1923 Family indet. Genus OGILVITES n. gen. Type species.-Ogilvites bicornis n. sp. Species included.-Knoxites argutula Zaspelova, 1959. Diagnosis.-Small, straight-backed, bilobate dre- panellids with prominent S2. Lobes coarsely reticu- late; ventral part of valves with striae parallel to free margin and/or reticulae. Velar bend parallel to free margin ; free margin smooth. Discussion.-The prominent, centrally located, nearly equal dorsal lobes of this genus distinguish it from other drepanellids. The position and types of ornamentation are likewise distinctive. The name of the genus is derived from the Ogilvie Mountains, eastern Yukon Territory, where it occurs. Geologic range.-Lower Devonian, Yukon Terri- tory; Upper Devonian (Frasnian), U.S.S.R. Ogilvites bicornis n. sp. Plate 6, figure 1 Description.-Valves subovate in lateral view, bilobate. Dorsum straight; free margins evenly rounded; cardinal angles curved. Left(?) valve slightly overlapping right (?) around free margin. £. 16 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY Prominent S2 extends from dorsal margin to mid- valve. Lobation consists of two conical tubercles, one on either side of S82, which extend well above hinge line. Tubercles reticulate with prominent ridges; about 10 meshlike polygons on each. Reticulae on tubercles limited ventrally by ridge extending be- neath S2 and dying out at anterior and posterior edges of reticulation. Ventral part of valve with five ridges paralleling free margin. Most dorsal ridge, mentioned above, limits tubercular reticulation; second ridge extends uninterruptedly to each cardinal angle; third ridge only as long as most dorsal ridge and branches me- dially into several reticulae; fourth ridge extends to each cardinal angle and branches near midvalve to form reticulae; fifth ridge borders entire margin of valve as velar bend; marginal area smooth. Material. -One complete carapace from the Prongs Creek Formation. Measurements.-The holotype carapace is 0.9 mm long. The height to the hinge line is 0.60 mm; the height to the tip of the dorsal tubercles is 0.65 mm. Types.-Holotype, GSC 29454. Discussion.-This species differs from Ogilvites argutulae (Zaspelova, 1959) from post-Snezha beds in the Novgorod district, U.S.S.R., in having more prominent dorsal tubercles wth reticulae more uni- form in size and distribution. Both species have a similar type of surface ornamentation (Zaspelova, 1959, pl. 8, figs. Ta, b), but O. argutula has a more prominent velar flange rather than a velar bend as in O. bicornis. Occurrence.-Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory. Superfamily HOLLINACEA Swartz, 1936 Family CTENOLOCULINIDAE Jaanusson and Martinsson, 1956 Subfamily CTENOLOCULININAE Jaanusson and Martinsson, 1956 Genus ABDITOLOCULINA Kesling, 1952 Abditoloculina clausa n. sp. Plate 6, figures 2-8 Abditoloculina sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 3. [Imprint 1967.] Description.-Lateral outline amplete to preplete. L1 projecting as cusp above hinge line; L2 rounded node below hinge line; L3 rounded node about same size as L2 but set higher on valve. S1 weak ; S2 deep, narrow, confined to dorsal third of valve. Prominent median spurlike node beneath S82, below and between L2 and L3. Two posterior tubercles, one just ventral to posterior cardinal angle, second in posteroventral quarter of valve beneath first tubercle. Tecnomorph with anterior node at or slightly above midheight on anterior margin; velum extends from node postero- ventrally to posterior third of valve. Anteroventral spur above but merging with velum. Heteromorph with six loculi extending from anterior node to pos- terior third of valve; anteroventral spur on third loculus. Loculi closed in ventral view (pl. 6, fig. 4). Surface finely granulose. Material.-Seven tecnomorphic and 3 heteromor- phic carapaces, and more than 10 valves from the McCann Hill Chert. Measurements.-The holotype, a heteromorphic carapace, is 0.90 mm long, 0.50 mm high, and 0.50 mm wide, including the spur. A tecnomorphic cara- pace (USNM 173746) is 0.90 mm long, 0.47 mm high, and 0.50 mm wide. There is little variation in size of individuals. Types.-Holotype, USNM 1708338; USNM 1738746, 178747, 173748, 173749. Discussion.-Kesling and Peterson (1958, p. 130) concluded that species of Abditoloculina may be dis- criminated by the number of loculi present in the heteromorphs. A. clausa differs from the 14 pre- viously described species of Abditoloculina in having only 6 loculi ; the lowest number previously recorded was 7 for the type species of the genus, A. insolita Kesling, 1952, and for A. binodat@ Kesling and Peterson, 1958. In addition, unlike any of the other species, the loculi of A. clawusa are closed in ventral view (pl. 6, fig. 4) ; that is, in a complete carapace with the valves in contact, no locular openings can be seen. The adult teecnomorph of A. clausa differs from those of other species in having relatively sub- dued spurs and a well-developed velum. This spe- cies is similar to A. binodata in having two posterior tubercles. The name of the species is derived from the Latin claousus, -a, -um, referring to the closed loculi. Occurrence.-USGS collections 6492-SD, 70832- SD, and 7033-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. paraty pes, Abditoloculina clausa? Plate 6, figure 9 Description.-Lateral outline preplete. L1 project- ing as cusp above hinge line; L2 rounded node be- low hinge line; L3 rounded node about same size as L2 but set higher on valve. S2 wide and deep. Promi- nent median spur beneath 82, below and between L2 and L3. Two posterior tubercles, one just below pos- terior cardinal angle, second in posteroventral quar- ter of valve beneath first tubercle. Anterior node at or slightly above midheight on anterior margin. Anteroventral posteriorly curved spur in anterior third of valve, on anteroventral margin. SYSTEMATIC PALEONTOLOGY 17 Material.-Three tecnomorphic right valves from the McCann Hill Chert. Measurements.-The figured specimen is 0.70 mm long and 0.40 mm high. Types.-Figured specimen, USNM 173750. Discussion.-The lobation of these three valves re- sembles that of tecnomorphs of Abditoloculina clausa n. sp. except for the pronounced median and anteroventral spurs; they also differ in lacking a well-defined velum. The spurs are suggestive of A. binodata Kesling and Peterson, 1958, but the tecno- morph of A. binodata has not been described. They may possibly be immature teenomorphs of A. clausa if the trimorphic concept (Bless and Jordan, 1971, 1972) is substantiated. However, this material is not adequate either to prove or disprove the trimorphic concept. Occurrence. -USGS collections 7033-SD, 7037- SD, and 7038-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Subfamily PARABOLBININAE Bless and Jordan, 1971 Genus PARABOLBINA Swartz, 1936 Parabolbina sp. Plate 8, figures 17, 18 Description.-Carapace elongate, slightly preplete, trilobate. Dorsal border straight; anterior border subround ; ventral border gently convex; posterior border tapering, subround. Anterior cardinal angle abrupt, more than 90°; posterior cardinal angle acuminate. All lobes confluent with ventral inflation. L1 low, nearly merged with small L2; L3 broad, oc- cupying posterior half of valve, separated anteriorly from L2 by deep geniculate S2 extending from dor- sum and ending abruptly near midvalve. Lateral sur- face ornamented with papillae of various sizes, free border smooth. Spurs located at anteroventral and posteroventral parts of valve, large, blunt, ends broken. Anterior spurs flattened and closer to free margin than posterior spurs. Material.-One tecnomorphic carapace from the Michelle Formation. Measurements.-The figured specimen is 0.93 mm long, 0.52 mm high, and 0.50 mm wide. Types.-Figured specimen, GSC 29449. Discussion.-This possibly immature specimen is somewhat similar to Parabolbina pulchella Kesling and McMillan, 1951, from the Bell Shale of Michi- gan, but lacks a tuberculate free border. P. hyper- cala Kesling and Tabor, 1953, from the Genshaw Formation of Michigan is more papillose and has L3 more pronounced. P. granosa (Ulrich, 1900), the type species of the genus, has smaller spurs and a less distinct L2. Occurrence.-Ludvigsen collection II-10, from the Michelle Formation, Blackstone River, Yukon Terri- tory. Family HOLLINIDAE Swartz, 1936 Subfamily HOLLININAE Swartz, 1936 Genus HOLLINA Ulrich and Bassler, 1908 Hollina sp. Plate 6, figure 23 Description. - Lateral outline amplete; hinge straight; cardinal angles obtuse. Free margins evenly rounded. L1 large, vertically elongate parallel to anterior border, terminating near middle of an- teroventral part of valve; L2 is small node; L3 is large bulb; L4 narrow, vertically elongate, smaller than L1. S1 narrow, somewhat sinuous; S2 deep, particularly in dorsal half of valve, sinuous, dorsally confluent with S1, passing between L2 and L3 and between two ventral lobes; S3 deep, vertical. All sulci reach ventral border. Two large ventral lobes, anterior one nodelike, ventral of L2, posterior one elongate-triangular, knoblike, ventral of L8. Mar- ginal tubercles on ridge or bend parallel with entire free margin; tubercles of ventral part larger. Entire surface covered with papillae, those on lobes being larger than those in sulci. Material.-One teenomorphic right valve. Measurements.-The figured specimen is 1.50 mm long and 0.93 mm high. Types.-Figured specimen, GSC 29441. Discussion.-This specimen appears to represent a species which is similar to Hollina insolens (UIl- rich, 1900) and H. pyzxidata Kesling, 1953. Both of those species, however, have a different arrangement of the two ventral lobes, which project as spurs, and L1 and L4 are more nodelike and L2 is smaller. Also, H. pyxidata is more posteriorly acuminate. H. com- pressa Kesling and Peterson, 1958, has a flatter valve surface and elliptical spurs. Occurrence.-Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory. Subfamily FALSIPOLLICINAE Bless and Jordan, 1971 Genus FALSIPOLLEX Kesling and McMillan, 1951 Falsipollex? multispinosus n. sp. Plate 7, figures 14-16 Description.-Lateral outline amplete. Hinge line straight; anterior margin curved; ventral margin less curved; posterior margin smoothly curved. L1 subdued, separated from L2 by short, shallow S1. L2 small, rounded; L3 bulbous, separated from ventral lobe by shallow groove. Velum in tecno- morph replaced by row of spines; velum in hetero- 18 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY morph forms an anteroventral, elongate elliptical dolonal pouch. Surface covered with fairly long blunt spines except for sulci. Ornamentation between spines finely granular. ) Material.-One heteromorphic right valve, one broken heteromorphic left valve, and one broken tecnomorphic left valve, all from the McCann Hill Chert. Measurements.-The holotype is 1.80 mm long and 1.05 mm high. Types.-Holotype, USNM 173761; USNM 173762, 173768. Discussion.-This species is only questionably as- signed to Falsipollex because it apparently lacks the two ventral spurs on the teenomorph which are con- sidered diagnostic of the genus by Kesling and Mc- Millan (1951, p. 67-68). However, the lobation, orna- mentation and dolonate character of the heteromor- phic velum are all more suggestive of Falsipollex than of any other hollinid genus. The specific name is derived from the abundant spines. Occurrence.-USGS collections 6492-SD, 7082- SD, from the McCann Hill Chert, Eagle (D-1) quad- rangle, Alaska. paratypes, Family HOLLINELLIDAE Bless and Jordan, 1971 Discussion.-Bless and Jordan (1971, p. 870-873, 880-881) proposed the family Hollinellidae for hol- linomorph ostracodes with velar and lobate dimorph- ism. They considered the "tecnomorphs" of hollinel- lid genera to be those with a wide frill and well- developed antrum and the "heteromorphs'"' to be those with a narrow frill and a canaliculus, because in genera such as Jordanites Bless, 1967 and Hollin- ella (Praehollinella) Bless and Jordan, 1971, juve- nile specimens have a wide frill (Bless and Jordan, 1971, p. 870-872). Later, Bless and Jordan (1972, p. 10-13) substituted the terms "presumable male" and "presumable female" for "tecnomorph" and "heteromorph," respectively. As originally proposed by Jaanusson and Martinsson (1956, p. 401-402), the term "tecnomorph" referred to juveniles of both sexes and the adult dimorph which resembled the juveniles; "heteromorph" referred to the adult di- morph which differed from the juveniles. Because there is no evidence that the adult male, rather than the female, did not develop dimorphism in the last molt, we are using the terms "tecnomorph" and "heteromorph" rather than "presumable male" and "presumable female." Although Bless and Jordan (1971) considered the wide frilled forms with a relatively narrower L3 to be tecnomorphs in the Hollinellidae, the only hollinellid for which we have growth stages, Adelphobolbina aliquanta n. sp., has narrow frilled juveniles with a relatively wide LB. Pending further study of Early and Middle Devo- nian hollinellids, we are considering the teecnomorph to be the narrow frilled form in the following descriptions. Genus HOLLINELLA Coryell, 1928 Hollinella ludvigseni n. sp. Plate 7, figures 1-3 2Hollinella sp., Copeland in Ludvigsen, 1970, p. 426. Description.-Valves subelliptical, preplete; hinge line long and straight. L1 broad, low; L2 small, ovate, nearly joined to L1; L3 bulbous, hemispher- ical, projecting to or slightly above hinge line. S1 short, shallow, indistinct; S2 deep, expanded ven- trally below proximal parts of L2 and L3; a shallow groove present posterior to L3. Ventral lobe from L1-L2 to posterior part of valve. Surface orna- mented with small, closely spaced papillae. Velar frill broad, papillose, extending from anterior car- dinal angle to midposteroventral margin, with a posterior spinelike projection. Frill flat to slightly convex in tecnomorph, slightly concave in hetero- morphic valves. Posteriorly, valves have marginal denticles. Material.-Two specimens from the Prongs Creek Formation, one specimen from the McCann Hill Chert. Measurements.-A heteromorphic valve is 1.20 mm long and 0.75 mm high ; a teenomorphic valve is 1.15 mm long and 0.70 mm high. Types.-Holotype, GSC 29462; paratypes, GSC 29463, USNM 173764. Discussion.-This species differs from Hollinello antespinosa (Ulrich, 1891) and H. plauta Kesling and Tabor, 1953, in having L3 hemispherical, with- out a dorsal projection. From H. pumila Kesling, 1953, and H. senticosa Kesling, 1953, it differs in having a much more pronounced frill in both di- morphs. Occurrence.-Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory; USGS collection 6492-SD, McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Hollinella paucituberculata n. sp. Plate 7, figures 6-8 ?Hollinella sp., Copeland in Ludvigsen, 1970, p. 426. Description. -Valves triangular-subelliptical, pre- plete; hinge long, straight. L1 broad, with dorsal cusp projecting above hinge line on left valve; L2 elongate, joined ventrally to L1; L3 large, bulbous, hemispherical, projecting above hinge line. S1 short, shallow to threadlike; S2 deep, joined dorsally to S1, with smooth, shallow geniculate ventral extension SYSTEMATIC PALEONTOLOGY 19 crossing ventral lobe to velar frill; an indistinct smooth groove along posterior edge of L3. Ventral lobe traversed by ventral extension of S2 and post- L3 groove. Lobes ornamented with widely spaced tubercles which are especially sparse on posterior quarter of valves. Velar frill flat, broad in hetero- morph, narrower in tecnomorph, extending from anterior cardinal angle to midposteroventral margin, with posterior spinelike projection. Valves with mar- ginal denticles posteriorly. Material. -More than 20 valves from the Prongs Creek Formation and the Michelle Formation. Measurements.-The average length of several specimens is 1.49 mm; the average height is 0.87 mm. Types.-Holotype. GSC 29494; paratypes, GSC 29495, 29496. Discussion.-The sparsely tuberculate lobes, the very sparsely tuberculate posterior, and the anterior cusp on the left valve serve to distinguish this spe- cies from the other species of Hollinella which have a ventral extension of S2. H. paucituberculata dif- fers from H. antespinosa (Ulrich, 1891) in having a more distinct ventral extension of S2, different surface ornamentation, and a differently shaped L3. It is more similar to H. sella Stover, 1956, but as illustrated by Stover (1956, pl. 111, figs. 1-6), H. sella has a more distinct L2 and a more bulbous L3 than H. paucituberculata. Also, H. paucituberculata has a small, posteriorly directed spine at the poste- rior cardinal angle which may prove to be of specific importance. The presence of this spine, the antero- dorsal cusp, and the pattern of the tubercles in this species are very similar to the same characters in Adelphobolbina aliquanta n. sp. Occurrence.-Ludvigsen collections II-13, and II- 14, from the Michelle Formation, Blackstone River, Yukon Territory, and Ludvigsen collection V-3, from the Prongs Creek Formation, Solo Creek, Yukon Territory. Genus ABORTIVELUM n. gen. Type species.-Abortivelum truncatum n. sp. Species included.-Only the type species. Diagnosis.-Hollinellid ostracodes with cuspate L1, distinct L2, L3 large and confluent with ventral lobe. Velum reduced to velar bend or ridge in teeno- morph, restricted to anterior and anteroventral part of valves in heteromorph. Heteromorphic velum not distinctly set off from domicilium. Discussion.-The reduced and suppressed velum distinguishes this genus from other hollinellid genera. Abortivelum most closely resembles Flacei- velum Kesling and Tabor, 1952, by the lack of dis- tinct separation between the heteromorphic velum and the domicilium, but in Flaccivelum the velum extends posteriorly beyond S2 and ends in a sharp spur, whereas in Abortivelum the velum does not extend posteriorly beyond S2 and merges smoothly with the surface of the valve. The name of the genus is based on the suppressed character of the velum. Geologic range.-Lower Devonian of Alaska. Abortivelum truncatum n. sp. Plate 6, figures 10-16 Description.-Lateral outline preplete. Hinge line straight; anterior margin rounded; ventral margin smoothly curved and merging with smoothly curved posterior margin. L1 cuspate on both valves; cusp projecting above hinge line in lateral view. L2 small, oblong, distinctly separated from L1 by very short but deep S1. L3 large, bulbous, projecting above hinge line in lateral view; separated from posterior slope of valve by shallow posterodorsal depression but not clearly separated posteroventrally or ven- trally. S2 deep, narrow, extending from dorsal mar- gin to about midvalve. Tecnomorph with velar bend extending from anterior cardinal angle to postero- ventral quarter of valve; heteromorph with velar frill extending from anterior cardinal angle to below $2. Velar frill merges with lateral surface of valve and is not distinctly separated from it. Surface finely granulose. Material.-Nineteen specimens, including one complete heteromorphic and three complete tecno- morphic carapaces, from the McCann Hill Chert. Measurements.-The holotype is 1.35 mm long and 0.85 mm high. Types.-Holotype, USNM 173752; USNM 173751, 1737583, 178754. Discussion.-This distinctive species does not closely resemble any previously described hollinellid. The specific name is derived from the truncated appearance of the heteromorph. Occurrence.-USGS collection 7032-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. paratypes, Genus ADELPHOBOLBINA Stover, 1956 Adelphobolbina aliquanta n. sp. Plate 6, figures 17-22 Adelphobolbina sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 6. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426 (part). Description.-Carapace elongate, amplete. Dor- sum straight; anterior margin narrowly rounded ; ventral margin smoothly curved; posterior margin denticulate, gently curved to acuminate posterior cardinal angle. L1 large, inflated, dorsally with tu- 20 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY bercle projecting above hinge line, which is most prominent on left valve, posteriorly with shallow de- pression (81) marking junction with fused L2. S2 deep, extending from dorsal border to midvalve, geniculate, concave anteriorly. L3 large, inflated, extending smoothly into ventral lobe, distinctly sepa- rated from posterodorsal field. Posterior surface of valve sloping gently to posterior margin. Cardinal angles distinct, anterior about 110°, posterior about 90°; some specimens with posterior cardinal spine. Velar frill extending from anterior cardinal angle to posteroventral part of valve, terminating posteri- orly in spine. Lateral surface with numerous tuber- cles on lobate areas; posterior surface with few tubercles. Smaller tubercles along dorsal margin and at outer edge of velar frill. Heteromorphic valves with wide straight velar frill; teenomorphic frill narrower. Material.-More than 40 specimens from the Mc- Cann Hill Chert; 1 specimen from the Michelle Formation. Measurements.-The holotype is 1.55 mm long and 0.90 mm high. A smaller teenomorph is 1.50 mm long and 0.85 mm high. Types.-Holotype, USNM 173755; paratypes, USNM 170341, 173756, 173757, 173758, GSC 29497. Discussion.-This species is similar to Adelpho- bolbina papillosa (Ulrich, 1891) but is less tubercu- late on the posterior slope, has a velar frill ending abruptly rather than smoothly as in A. papillosa, has an anterodorsal cusp on the left valve, and is more acuminate posteriorly. A. aliquanta differs from A. megalia (Kesling and Tabor, 1953) and 4. pinguis (Kesling and McMillan, 1951) in being more coarsely tuberculate, but it is not coarsely spinose like A. spicata (Kesling and McMillan, 1951). A. medialis Stover, 1956 and A. trilobata (Stewart, 1936) have a longer S2 than A. aliquanta. According to Warthin (1987, card 66), A. bulbosa (Tolmachoff, 1926), from the Middle Devonian (bed Db) of Elles- mere Island, is evenly pustulose, except on the velar frill, and A. (Tolmachoff, 1926) is pustu- lose on the lobes but not on the posterior slope (War- thin, 1987, card 67). The specific name aliquanta refers to the moderate number of tubercles. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7037-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collection II-13 from the Michelle Formation, Black- stone River, Yukon Territory. Adelphobolbina prongsensis n. sp. Plate 7, figures 9-13 Adelphobolbina sp., Copeland in Norris, 1967a, p. 138, 140; Copeland in Ludvigsen, 1970, p. 426 (part). Description. - Carapace elongate, subelliptical, slightly preplete in lateral view. Dorsum straight; anterior margin rounded; ventral margin gently curved; posterior margin rounded. S2 deep, extend- ing from dorsal border to midvalve, slightly concave anteriorly and continued as shallow narrow constric- tion nearly to ventral frill. L1 large, inflated, with shallow depression posteriorly marking junction with fused L2. L3 large, inflated, slightly constricted at confluence with gently curved ventral lobe. Pos- terior surface of valve sloping gently to posterior margin. Cardinal angles obtuse, anterior about 120°, posterior about 100°. Velar frill extending from anterior cardinal angle to posteroventral part of valve, wider anteriorly. Lateral surface with papillae of two sizes; smaller papillae on lobes and larger ones on posterior part of valves and, on tecnomorphic valve, between velar frill and lobate areas. Heteromorphic valve with wide, straight velar frill almost in contact with ventral lobe; larger papillae restricted to posterior part of valve. Material.-Five specimens from the Prongg Creek Formation. Measurements.-The holotype is 1.45 mm long and 0.93 mm high. A teenomorphic valve, paratype GSC 29501, is 1.45 mm long and 0.84 mm high. Types.-Holotype, GSC 29498; paratypes, GSC 29499, 29500, 29501, 29502. Discussion.-This species is most similar to Adel- phobolbina papillosa (Ulrich, 1891), from the Jeffer- sonville Limestone of Indiana and A. megalia (Kes- ling and Tabor, 1953) from the Genshaw Formation of Michigan. A. papillosa, however, has more and larger papillae and, on the heteromorph, a more dis- crete, prominent velar frill (Kesling and Tabor, 1953, pl. 3, figs. 16, 17) ; A. megalia has a broader L3, more discrete velar frill, and apparently lacks the faint ventral constriction at the base of $2 which slightly separates L1 from the ventral lobe. This ventral constriction or prolongation of $2 is not as well developed as that in A. medialis Stover, 1956, where it is a definite part of $2. A. medialis, unlike A. prongsensis, is evenly papillose. Occurrence.-Ludvigsen collections V-3, V-4, from the Prongs Creek Formation, Solo Creek, Yu- kon Territory. Adelphobolbina sp. cf. A. medialis Stover, 1956 Plate 7, figures 4, 5 Adelphobolbina medialis Stover, 1956, p. 1104-1105, pl. 112, figs. 4-9. Description.-Lateral outline amplete; dorsum straight; anterior and posterior margins evenly rounded; ventral margin smoothly curved. L1 large, SYSTEMATIC PALEONTOLOGY 21 low, separated from small oval L2 by short, shallow, indistinct S1. S2 wide, deep, extending more than half height of valve and continued ventrally to mar- gin of domicilium by shallow depression. L8 large, inflated, merging with ventral lobe but distinctly separated from relatively narrow posterodorsal field. Cardinal angles obtuse. Velar frill extending from anterior cardinal angle to posterior edge of L8. Sur- face of domicilium evenly papillose except for deep parts of S2. A few scattered papillae present on velar frill. Material.-Twenty valves from the McCann Hill Chert. Measurements.-The two figured specimens are 1.25 mm long and 0.77 mm high and 1.25 mm long and 0.75 mm high, respectively. Types.-Figured specimens, USNM 173759, 173760. Discussion.-The specimens from the McCann Hill Chert all appear to be immature teenomorphs. They resemble Adelphobolbina medialis Stover, 1956, in having S2 long and extending in a shallow furrow to the velar frill, in the evenly papillose surface and in the inflated L8. However, in typical A. medialis, L2 is completely merged with L1, and S1 is entirely suppressed. Also, A. medialis appears to lack papil- lae on the velar frill. A. medialis is from the Windom Member of the Moscow Shale (Middle Devonian) of western New York, and until definite adult speci- mens from the Lower Devonian of Alaska can be found it seems better to compare the McCann Hill Chert specimens with A. medialis rather than assign- ing them to the species. Occurrence.-USGS collections 6492-SD, 70833- SD, 7037-SD, 7038-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Genus FLACCIVELUM Kesling and Peterson, 1958 Flaccivelum sp. Plate 8, figures 15, 16 elongate, amplete. L2 some- what elongate, partly fused with L1; dorsal edge of L1 extending to hinge line. S2 deep, curved anteri- orly, extending from hinge line to near midvalve. L3 broad, extending slightly above hinge line. L1 and L3 confluent with ventral lobe. Posterior part of valve gently convex, not lobate. Heteromorph with broad flat frill, confluent with lateral surface and deflected laterally at its posterior end. Material.-One heteromorphic right valve from the Michelle Formation. Measurements.-The figured specimen is 1.10 mm long and 0.70 mm high. Types.-Figured specimen, GSC 29509. Discussion.-This specimen is most nearly similar to Flaccivelum teleutaea (Kesling and Tabor, 1952) and F'. informis (Ulrich, 1891), but differs from both in lacking a posteroventral projection of the ventral lobe and in having L3 confluent with the ventral lobe. Occurrence.-Ludvigsen collection II-10, Michelle Formation, Blackstone River, Yukon Territory. Genus INFRACTIVELUM n. gen. Type species.-Infractivelum acuminatum n. sp. Species included.-Infractivelum spiculosum n. sp. Diagnosis.-Hollinellid ostracodes with distinct L2 and prominent L3 continuous with ventral lobe. Velum continuous from anterior cardinal angle to midposteroventral slope in both teenomorphs and heteromorphs. Heteromorphic velum only weakly separated from lateral surface of domicilium. Tecno- morphic velum of same extent as heteromorphic velum but narrow and flaring away from free mar- gin. L1 may extend as cusp above hinge line on left valve of adult teenomorph. Discussion.-The lobation of Infractivelum differs from that of Hollinell«a Coryell, 1928, in having L3 confluent with the ventral lobe rather than bulbous, and from that of Adelphobolbina Stover, 1956, in having L3 narrower and more prominent. Infracti- velum resembles Ruptivelum Kesling and Weiss, 1953, in having a relatively distinct L2, but differs from that genus in having an uninterrupted teeno- morphic velum even in immature specimens (pl. 8, fig. 20). The heteromorphic velum of Infractivelum is like that of Flaccivelum Kesling and Tabor, 1952, but lacks the outward posterior swing of that genus, and the lobation of Infractivelum is more distinct. Jordanites Bless, 1967, and Hollinella (Praehollin- ella) Bless and Jordan, 1971, both have the velum merging gradually with the domicilium at its pos- terior end rather than truncated as in Infractivelum. The name is based on the unbroken character of the velum. Geologic range.-Lower Devonian of Alaska and Yukon Territory. Infractivelum acuminatum n. sp. Plate 8, figures 19-23 f Adelphobolbina sp., Copeland in Ludvigsen, 1970, p. 426 (part). Description. - Carapace elongate, subelliptical, preplete, somewhat acuminate posteriorly. Dorsum long, straight; lateral borders subround ; free mar- gins gently curved. S2 deep, slitlike, extending from dorsal margin to midvalve, slightly concave anteri- orly. L1 large, inflated, with short dorsal cusp ex- tending above hinge line of left valve. L2 fused to L1 ventrally but separated dorsally by short S1. L8 large, inflated, somewhat angular dorsally and ex- tending to or beyond hinge line. Posterior surface of 22 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY valve sloping gently to posterior margin. Anterior cardinal angle broad, about 110° ; posterior cardinal angle narrow, nearly 90°. Velar frill extending from anterior corner to posteroventral part of valve, nar- row in tecnomorphs. Heteromorphic valves with wider frill confluent with L1 and ventral lobe. Lat- eral surface with uniform fine papillae. Material.-Five specimens from the Prongs Creek Formation. Measurements.-The holotype is 1.60 mm long and 1.00 mm high. A tecnomorphic left valve is 1.30 mm long and 0.75 mm high. Types.-Holotype, GSC 29503; paratypes, GSC 29504, 29505, 29506, 29507. Discussion.-Small specimens which are consid- ered to be immature tecnomorphs of this species do not have as acuminate an L3 as the adults. Occurrence.-Ludvigsen collections V-3 and V-4, from the Prongs Creek Formation, Solo Creek, Yu- kon Territory. Infractivelum spiculosum n. sp. Plate 8, figures 24-27 Hollinella? sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 7. [Imprint 1967.] Description.-Lateral outline preplete; dorsal margin straight; anterior margin smoothly curved; ventral margin less sharply curved; posterior mar- gin curved up to sharp posterior cardinal angle, which is about 90°. Anterior cardinal angle rounded. L1 with anterodorsal cusp which projects over hinge line on both valves; L2 small, ovate, separated from L1 by short shallow S1; L3 bulbous, acuminate, with point directed perpendicular to lateral surface. S2 wide, deep to about midheight of valve, curved an- teriorly beneath L2 and extended as shallow groove around anterior end of ventral lobe to velar frill. Posterior part of valve slopes smoothly to posterior margin. Surface finely granulose with seattered large papillae on the lobate areas, especially prominent on L8 and parallel to velar frill. Velar frill extends from anterior cardinal angle to posteroventral part of valves; wide, confluent with lateral surface, and curved toward contact margin in heteromorph ; nar- rower and reflexed away from contact margin in tecnomorph. Material.-Six specimens from the McCann Hill Chert. Measurements.-The holotype is 1.55 mm long and 0.92 mm high. A teecnomorphic paratype is 1.30 mm long and 0.77 mm high. Types.-Holotype, USNM 107342; USNM 173765, 173766, 173767, 1783768. Discussion. - Infractivelum - spiculosum - differs from I. acuminatum in having a more acuminate L3, paratypes, distinct anterodorsal cusps on both valves and larger, and less regularly distributed papillae. The specific name refers to the sharp, anterodorsal cusps. Occurrence. - USGS collections 6492-SD and 7033-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Superfamily KIRKBYACEA Ulrich and Bassler, 1906 Family ARCYZONIDAE Kesling, 1961 Genus CHIRONIPTRUM Kesling, 1952 Chironiptrum reticularis n. sp. Plate 8, figures 9-14 Chironiptrum sp., Copeland in Ludvigsen, 1970, p. 426, 427 (part). Description.-Valves subelliptical, slightly post- plete; right larger than left. Hinge line straight; free margins evenly curved. Deep pit near center of valve. Lateral surface surrounded by wide flaring frill confluent with dorsal ridge. Greatest height and width posterior. Lateral surface strongly reticulate; frill and channel smooth. Marginal ridge on both valves ; ridge on right valve larger, somewhat tuber- culate. Thin ridge at contact margin of right valve for closure against marginal ridge of left valve. Marginal ridge extending posteriorly beyond frill in some specimens. Material.-Six specimens from the Michelle For- mation. Measurements.-Average of several specimens, length, 0.80 mm, height, 0.50-0.55 mm. Types.-Holotype, GSC 29456; paratypes, GSC 29457, 29458, 29459, 29460, 29461. Discussion.-This species is typical of the genus, but differs from Chironiptrum oiostathmicum Kes- ling, 1952, the type species, in being more coarsely reticulate, in lacking papillae at the intersections of the reticulae, and in lacking spurlike projections at the cardinal angles. Occurrence.-Ludvigsen collections II-10 and II- 13 from the Michelle Formation, Blackstone Creek, Yukon Territory. Chironiptrum limitaris n. sp. Plate 8, figures 2-8 Chironiptrum sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 2. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426, 427 (part). Description.-Valves subelliptical, slightly post- plete; hinge line straight; anterior and posterior margins evenly curved ; ventral margin gently curved to nearly straight. Deep drop-shaped pit slightly an- terior of center of valve. Lateral surface surrounded by wide flaring frill confluent with dorsal ridge, which is only faintly visible along dorsal margin in lateral view. Lateral surface finely reticulate, some papillae at junctions of ridges forming reticulation. SYSTEMATIC PALEONTOLOGY Frill and channel smooth. Marginal ridge around free margin. Material.-More than 60 specimens from the Mc- Cann Hill Chert, 1 specimen from the Prongs Creek Formation. Measurements.-The holotype is 0.80 mm long, 0.50 mm high, and 0.40 mm wide. Measurements of 53 other specimens are shown in figure 6. Types.-Holotypes, USNM 173770; paratypes, GSC 29455, USNM 170337, 173769, 178771, 173772, 173773. , Discussion.-This species is most similar to Chi- roniptrum oiostathmicum Kesling, 1952, in shape, size of reticulation, and presence of papillae on the lateral surface, but the reduction of the frill along the dorsal margin in C. limitaris distinguishes it from that species. C. limitaris differs from C. reticu- laris n. sp. in the presence of papillae on the lateral surface of the valve and in being more finely reticu- late. This species is fairly abundant in collection from the McCann Hill Chert, but only one collection, USGS collection 7037-SD, contains many immature specimens; the other collections contain mostly adults. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7037-SD, 7038-SD, all from the Mc- Cann Hill Chert, Eagle (D-1) quadrangle, Alaska; 23 Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory. Genus OBOTRITIA Adamczak, 1968 Obotritia? sp. Plate 8, figure 1 Description. outline amplete to slightly preplete; hinge line straight; free margins evenly rounded. Subelliptical high carina approximately concentric about obscure muscle spot but eccentric to margins of valve; low dorsally, slightly sinuate anterodorsally, high and flaring anteroventrally, ventrally, and posteriorly. Posterior quarter of valve extends beyond carina. Anterior cardinal angle pro- duced as anterodorsal spine; posterior cardinal angle broken. Lateral surface enclosed by carina very finely punctate; surface outside carina smooth. Material.-One left valve from the McCann Hill Chert. Measurements.-The figured specimen is 0.70 mm long and 0.47 mm high. Types.-Figured specimen, USNM 178774. Discussion.-This single specimen is questionably assigned to Obotritia Adamezak, 1968, because it has a muscle spot rather than a central pit and an ellip- tical carina which is confluent with the dorsal ridge. However, Obotritia eifeliensis Adamczak, 1968, as described and illustrated by Adamczak (1968, p. 85- . T | T T T sa | & L i e EXPLANATION y 5 ce ._ B + 6: ® @ +- C jar 1. (2 9 4 5 6 %% 2 L_ Number of specimens with s s s % su 3 identical measurements 6 * % Z a -* 6 . a 00 w [- e oo o - F © 3 m s X 4 saul -I 3 | 1 | | | | I 1 0 0 0.5 1.0 MAXIMUM LENGTH, IN MILLIMETERS FIGURE 6.-Scatter diagram of maximum length versus maximum height for Chironiptrum limitaris n. sp.; 53 speci- mens from the McCann Hill Chert (USGS colln. 7037-SD, paratype slide USNM 173772). 24 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 86, pl. 38, figs. 1-3) is coarsely reticulated and the carina is parallel to the free margins. Occurrence.-USGS collection 7037-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Family KIRKBYELLIDAE Sohn, 1961 Genus KIRKBYELLA Coryell and Booth, 1933 Subgenus KIRKBYELLA Coryell and Booth, 1933 Kirkbyella (Kirkbyella) sp. Plate 9, figure 1 Description.-Lateral outline amplete; anterior and posterior margins smoothly curved; ventral margin straight. Essentially unisulcate; S1 obsolete, S2 narrow, deep, extending from hinge line to one- half or one-third height of valve and curving dor- sally and ventrally to outline small rounded L2. Ven- tral lobe large, massive, projecting as sharp spine posteriorly, separated from ventral margin by nar- row rim. Cardinal angles obtuse. Valve covered with very fine striations approximately parallel to mar- ging. Material.-Three valves from the McCann Hill Chert. Measurements.-The figured specimen is 0.60 mm long and 0.30 mm high. Types.-Figured specimen, USNM 173775. Discussion.-These specimens have the narrow rim beneath the posterior part of the ventral lobe characteristic of Kirkbyella (Kirkbyella) as de- scribed by Sohn (1961, p. 143) and are consequently assigned to that subgenus. The specimens are not sufficiently complete to justify giving them a formal name, but the distinctive striated ornamentation is unlike that of any other described species of Kirk- byella. Occurrence.-USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. 73> Suborder NODELLOCOPINX Becker, 1968 Superfamily NODELLAGCEA Becker, 1968 Family NODELLIDAE Zaspelova, 1952 Genus HANAITES Pokorny, 1950 Type species.-Halliella (Hanaites) givetiana Po- korny, 1950. Species included.-Proplectrum - platum - Kesling and McMillan, 1951. ?Eurychilina mirabilis Pole- nova, 1952. Hanaites linearis n. sp. Hanaites brevis n. sp. Hanaites spinosus n. sp. Revised diagnosis.-Unisulcate paleocope ostra- codes, preplete to amplete in lateral outline. Sulcus vertical or slanted posteriorly. Velum developed an- teriorly as palmate or hooklike projection (hamus) in tecnomorph; heteromorph with velum widened and bent away from free margin anteriorly. Lateral surface reticulate or punctate; velum and sulcus smooth. Discussion. -Hanaites, originally considered a subgenus of Halliella by Pokorny (1950, p. 599), was placed in the Hollinidae by Stover (1956, p. 1105) because the velar dimorphism of the heteromorphs which he had found suggested a relationship with the hollinids. Recently Becker (19682, p. 129-131; 1968b, p. 553-555) proposed the suborder Nodello- copina and the superfamily Nodellacea to include the family Nodellidae Zaspelova, 1952, with two genera, Nodella Zaspelova, 1952, and Zaspe- lova, 1952, which have hamal dimorphism, that is, velar dimorphism in which the teenomorphic velum forms a projection or hook (hamus) anteriorly and the heteromorphic velum widens and flares away from the contact margin anteriorly. This type of dimorphism is also characteristic of Hanaites, which accordingly is here assigned to the family Nodellidae. Geologic range.-Lower Devonian of Alaska and Yukon Territory; Middle Devonian of the east- central United States, Czechoslovakia, and possibly the U.S.S.R. Hanaites linearis n. sp. Plate 9, figures 2, 3 Description.-Carapace elongate; lateral outline preplete. Hinge line straight; anterior border evenly curved; ventral border straight to convex, inclined; posterior border more acutely convex, somewhat acuminate. Anterior cardinal angle about 100°; posterior cardinal angle 75° to 80°. Sulcation consisting of S2, which slants slightly posteriorly from dorsal margin to slightly below midvalve. S2 widens and deepens ventrally, ending in rounded pit, and is bounded, except dorsally, by smooth rim. Lo- bation consisting of confluent L1 and L2, ventral lobe and LS. Velar frill continuous from posterodorsal corner to midanterior margin, in heteromorph becoming broader anteriorly, in tecnomorph of equal width throughout and terminating anteriorly in a spurlike process (hamus). Smooth antrum between velar frill and fine marginal ridge. Marginal ridge projects slightly beyond velar frill posteroventrally. Surface of valves deeply reticulate, except for S2 and anterodorsal corner, with row of reticulae at dorsal contact of velar frill and domicilium. Dorsal crest limits reticulae dorsally, extending as fine ridge from near anterior end of velar frill, above L1-L2, forming part of rim around 82, projecting across L3 as a straight ridge posteriorly from the postero- SYSTEMATIC PALEONTOLOGY 25 dorsal corner of $2 and ending in a downcurved, more broadly projecting angulation. Material.-Four specimens from the Prongs Creek Formation. Measurements.-The holotype is 1.38 mm long and 0.65 mm high. Types.-Holotype, GSC 29478; paratype, GSC 29477. Discussion.-This species differs from Hanaites givetiana Pokorny, 1950, the type species of the genus, in the development of a dorsal crest and in having S2 inclined posteriorly rather than vertical (Pokorni, 1950, p. 600.) H. platus (Kesling and Mc- Millan, 1951) lacks the dorsal crest of H. linearis, has a more pronounced palmate anterior spur and a posterodorsal node. Hurychilina mirabilis Polenova, 1952, appears to be referable to Hanaites, but the illustrations of this species (Polenova, 1952, pl. 1, fig. 5; Rozhdestvenskaya, 1962, pl. 6, figs. 1, 2) indi- cate that it has a spine at the posterior cardinal angle and that its S2 is more vertical than that of H. linearis. Differences between H. linearis and the two new species, H. brevis and H. spinosus, are dis- cussed under those species. The specific name of H. linearis is based on the linear character of the dorsal crest. Occurrence.-Ludvigsen collections V-3, V-4, and V-5 from the Prongs Creek Formation, Solo Creek, Yukon Territory. Hanaites brevis n. sp. Plate 9, figures 4-9 Hanaites sp. B, Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 5. [Imprint 1967.] Description.-Carapace short for genus; lateral outline slightly preplete. Hinge line straight; ante- rior border evenly curved; ventral border gently convex, inclined posteriorly; posterior border more sharply convex. Anterior cardinal angle more than 130° ; posterior cardinal angle 90° to 115°. 82 slants slightly posteriorly to midvalve or slightly below, widens and deepens ventrally, ending in rounded pit, and is bordered by narrow, smooth rim. Velar frill narrow, reduced anterodorsally ; in tec- nomorph produced as small, thin, ventrally directed hooklike spur (hamus) at midheight of valves on anterior margin; in heteromorph wider anteroven- trally and deflected away from free margin at about midheight, spur lacking. Antrum between velar frill and marginal ridge reticulate in both heteromorph and tecnomorph. Marginal ridge widens postero- ventrally, projects from beneath velar frill posteri- orly, and is deflected away from contact margin on each valve posterodorsally so that a small oval cham- ber, open posteriorly, is formed on the posterodorsal end of both teecnomorphic and heteromorphic cara- paces. Surface of valves deeply reticulate except for an- terodorsal corner, $2, and velar frill. Row of larger reticulae at dorsal contact of velar frill and domi- cilium. Four to six reticulae between ventral end of $2 and velar frill. Narrow dorsal crest extends from posterodorsal end of S2 posteriorly and bends ven- trally before reaching posterior cardinal angle. Pos- terior end of dorsal crest raised as low knob on some specimens. Narrow groove on each valve between dorsal crest and hinge line (pl. 9, fig. 8). Material.-More than 110 specimens from the Mc- Cann Hill Chert. Measurements.-The holotype is 1.33 mm long and 0.75 mm high. A figured paratype (USNM 173776) is 1.35 mm long and 0.70 mm high. The length and height of 54 specimens, including the holotype, are shown in figure 7. Types.-Holotype, USNM 173777; 170340, 173776, 1787772, 173778, 173779. Discussion. -Hanaites brevis differs from other species assigned to Hanaites in being relatively short and stout and in having a weak, poorly developed hamus. It most closely resembles H. linearis n. sp. in having a linear dorsal crest on each valve, but H. linearis is more elongate, the dorsal crest is better developed, and there are three to four reticulae be- tween S2 and the velar frill rather than four to six as in H. brevis. Also, the heteromorphic velar frill is wider in H. linearis than in H. brevis. The specific name of H. brevis refers to its short lateral outline. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7037-SD, and 7088-SD, from the Mc- Cann Hill Chert, Eagle (D-1) quadrangle, Alaska. paratypes, Hanaites spinosus n. sp. Plate 9, figures 10-15 Hanmaites sp. A, Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 4. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426. Description. elongate; lateral outline preplete. Dorsal border straight; anterior border broadly rounded; ventral border straight, inclined ; posterior border narrowly rounded. Anterior cardi- nal angle about 110°, posterior cardinal angle about 90°. Sulcation consisting of S2, which slants slightly posteriorly to midvalve, terminating in deep rounded pit. Lobation consisting of combined L1 and L2, ventral lobe, and L3, all confluent. Velar frill continuous from somewhat above mid- height on anterior margin to posterodorsal cardinal angle; widest on anterior half of valve; projecting ventrally as hooklike spur in tecnomorphs, wider and bent away from free margin anteriorly in hetero- 26 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY 1.0 MAXIMUM HEIGHT, IN MILLIMETERS 0 on I EXPLANATION o l * ® ## @ ++ e 1 2 3 4 o o o Number of specimens with e e @ identical measurements o - e@e 0 _ e o e % o @ o o o e @ e @ : < @ @ zea & | | 0 0.5 1.0 1.5 MAXIMUM WIDTH, IN MILLIMETERS FIGURE 7.-Scatter diagram of maximum length versus maximum height for Hanaites brevis n. sp.; 54 speci- mens from the McCann Hill Chert (USGS collin. 6492-SD, paratype slide 173779). morphs. Smooth antrum between velar frill and fine marginal ridge, which projects posteriorly beyond velar frill. Dorsal ridge on left valve overreaches dorsal margin of right valve. Surface of valves, ex- cept for S2 and anterodorsal corner, deeply reticu- late, with row of larger pitlike reticulae at dorsal proximal edge of velar frill. Anterodorsal corner more finely reticulate and with tendency to develop oblique ridge parallel to anterodorsal free margin. Large, blunt, posterodorsally inclined reticulate spine on L3 in posterodorsal part of valve below hinge line. Material.-Twenty-four specimens from the Mc- Cann Hill Chert and two specimens from the Mi- chelle Formation. Measurements.-The holotype (USNM 1783780) is 1.30 mm long and 0.75 mm high. An immature tec- nomorph (USNM 173781) from the McCann Hill Chert is 1.00 mm long and 0.50 mm high. An imma- ture tecnomorph from the Michelle Formation is 0.70 mm long and 0.40 mm high; a mature specimen (GSC 29479) from the Michelle Formation is 1.05 mm long and 0.60 mm high. Types.-Holotype, USNM 173780; paratypes, USNM 170339, 173781, 173782, 173783, GSC 29479, 29479a. Discussion. -Hanaites spinosus has a much more pronounced posterodorsal spine than H. platus (Kes- ling and McMillan, 1951) and is less elongate than that species. The other described species of Hanaites apparently lack the prominent posterodorsal spine. H. linearis n. sp. and H. brevis n. sp. may develop a low node at the posterodorsal angulation of the dor- sal crest, especially in immature tecnomorphs, but this node is not as large as the spine of H. spinosus, nor does H. spinosus have the dorsal crest of these species. The spines of H. spinosus are better devel- oped on the left valves of adults than they are on the right, and the presence or absence of the anterodor- sal ridge appears to be variable within the species. Some specimens are nearly smooth; this may be caused by differences in preservation or may be a variation within the species. There is also variation in the degree of development of the ventral lobe, which is prominent in some specimens, especially small teenomorphs. Furthermore, the posterodorsal spine is more prominent in young individuals. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7037-SD, 7038-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Lud- vigsen collection II-10, from the Michelle Formation, Blackstone River, Yukon Territory. SYSTEMATIC PALEONTOLOGY 27 Superfamily OEPIKELLACEA Jaanusson, 1957 Family APARCHITIDAE Jones, 1901 Genus SUBARCTICHITES n. gen. Type species.-Subarctichites serratulus n. sp. Species included.-Aparchites crossotus Kesling, 1952. Diagnosis.-Long hinged aparchitid ostracodes with distinct cardinal angles; free margin with row of denticles on anterior and venter but not on pos- terior. Velar bend smooth or denticulate. Hinge in- cised, of ridge and groove type. No dimorphism observed. Discussion.-This genus probably includes numer- ous aparchitids described from the Devonian which have denticulate margins, but the presence or ab- sence of marginal denticles is not mentioned in many descriptions. Subarctichites differs from Apar- chites s.s. as discussed by Swartz (1969, p. 1239) in the character of the free margin. The anterior posi- tion of the denticles on the free margin distinguish Subaretichites from the nonsulcate and nonspinose species assigned to the dimorphic genus Gravia Pole- nova, 1953, in which the denticles are posterior or posteroventral. The lack of cruminal dimorphism in Subarctichites separates it from the superficially similar genera Saccarchites Swartz and Whitmore, 1956, and Phlyctiscapha Kesling, 1953. The name of the genus is based on its occurrence near, but south of, the Arctic Circle. Geologic range.-Lower Devonian of Alaska and Yukon Territory, Middle Devonian of Michigan. Subarctichites serratulus n. sp. Plate 9, figures 16-24 Saccarchites? sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 15. [Imprint 1967.] Saccarchites sp., Copeland in Ludvigsen, 1970, p. 426. Description.-Valves subovate, amplete to slightly preplete in lateral outline. Dorsal border of left valve nearly straight; dorsal border of right valve slightly arched. Free margins evenly rounded. Great- est height and length nearly median ; greatest thick- ness slightly posteromedian. Cardinal angles nearly equal, about 120°. Margin of valves with row of stout discrete spines extending from above midan- terior margin to posteroventral part of valve; spines larger and more distant from contact margin on right valve. Supramarginal bend of same extent, parallel to and separated from marginal spines. Surface smooth or finely granulose. Hinge of right valve grooved; ends of hinge of left valve with notches at cardinal angles. Muscle scar is dark, round spot in central part of valve. Material.-Thirty-six specimens from the McCann Hill Chert; six specimens from the Prongs Creek Formation. Measurements.-The holotype is 1.20 mm long, 0.87 mm high, and 0.87 mm wide. The measurements of six specimens from the Prongs Creek Formation are as follows (in millimeters) : length, 1.05, height, 0.70; length, 1.40, height, 1.00 ; length, 1.20, height, 0.85; length, 1.40, height, 1.00; length, 1.32, height, 1.05; length, 1.35, height, 1.00. Types.-Holotype, USNM 173784; paratypes, USNM 170350, 178785, 173786, 173787, 173788, GSC 29483, 29484, 29485, 29486. Discussion.-This species is very similar to Sub- aretichites crossotus (Kesling, 1952), from the Bell Shale of Michigan, in shape and presence of a mar- ginal row of spines. S. serratulus, however, has a more elevated right dorsal margin and a marginal row of spines and a supramarginal bend instead of two rows of marginal spines like S. crossotus. Both species apparently have approximately the same di- mensions, although the holotype of S. crossotus (Kesling, 1952, p. 24) is somewhat smaller than most of the specimens of S. serratulus. The cardinal sockets on the inside of the left valve appear to be for the reception of the cardinal angles of the right valve; no teeth or other projections have been ob- served in the right valve which would fit these sockets. The specific name of S. serratulus refers to the marginal denticles. Occurrence.-USGS collections 6492-SD, 7032- SD, 70833-SD, 7037-SD, all from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collections V-3, V-4, from the Prongs Creek Forma- tion, Solo Creek, Yukon Territory. Genus LIBUMELLA Rozhdestvenskaya, 1959 Libumella sp. cf. L. discoides Rozhdestvenskaya, 1959 Plate 10, figures 1-5 Libumella discoides Rozhdestvenskaya, 1959, p. 134, pl. 4, figs. la, b. Libumella sp., Copeland in Norris, 1967a, p. 115, 127, 138, 140; Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 9. [Imprint 1967.]; Copeland in Ludvigsen, 1970, p. 426. Description. -Carapace large, subcircular in out- line; length greater than height; anterior margin lower than posterior. Hinge short, incised, at mid- valve. Left valve larger than right, overlapping right along entire free margin; left valve 'right at hinge line. Each valve with thin marginal ridge. Valve surface ornamented with deep punctae except marginally and in area of circular adductor sear. Material.-More than 80 specimens from the Mc- Cann Hill Chert; more than 60 specimens from the Prongs Creek Fo mation. Measurements. - Several specimens from the Prongs Creek Formation range from 0.95 to 1.45 28 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY mm in length and from 0.80 to 1.20 mm in height; the length /height ratio is 1.2. Types. - Figured specimens, USNM 170344, 1783789; GSC 29480, 29481. Discussion.-These specimens may be conspecific with those described and drawn by Rozhdestvens- kaya (1959, p. 134, pl. 4, figs. 1a, b) from the Biya beds (Eifelian) of Bashkiria The punctae of the Russian specimens may be slightly larger than those of the North American specimens. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7038-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collections V-3, V-4, V-5 from the Prongs Creek Formation, Solo Creek, Yukon Territory. Libumella sp. cf. L. circulata Rozhdestvenskaya, 1962 Plate 10, figures 6-8 Libumella circulato Rozhdestvenskaya, 1962, p. 179, pl. 3, figs. 3a-g. Description.-Lateral outline subcircular to ellip- tical; dorsum rounded ; free margins evenly curved. Narrow, subdued rim around free margins of over- lapping valve continued as weak margin parallel to dorsum ; overlapped valve without rim. Shell surface smooth. Hinge short, straight, apparently slightly incised. Material.-One specimen from the McCann Hill Chert; five specimens from the Prongs Creek For- mation. Measurements.-The figured specimen from the McCann Hill Chert is 1.70 mm long and 1.35 mm high. Types.-Figured specimens, USNM 1783790, GSC 29482. Discussion.-These specimens differ from Libum- ella circulata as illustrated by Rozhdestvenskaya (1962, pl. 3, figs. 3a, b) in having the rim parallel to the dorsum less well developed, and in the speci- men from the McCann Hill Chert having a better developed rim around the free margins. Otherwise they appear close to figures of typical L. circulata. Occurrence.-USGS collection 7032-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka; Ludvigsen collections V-3, V-4, V-5, from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. Suborder KLOEDENELLICOPINA Scott, 1961 Superfamily PARAPARCHITACEA Scott, 1959 Family PARAPARCHITIDAE Scott, 1959 Genus NEOAPARCHITES Boulek, 1936 Neoaparchites? sp. aff. N.? insericus (Rozhdestvenskaya, 1962) Plate 10, figures 9-12 Punctaparchites insericus Rozhdestvenskaya, 1962, p. 174, pl. 1, figs. ba-g. Description. outline suboval, preplete. Dorsum very slightly curved ; anterior and posterior ends evenly curved ; ventral margin broadly curved. Hinge straight, slightly incised. Left valve overlaps right very slightly ; interior of left valve channelled along free margin to receive edge of right. Surface punctate except for postcentral smooth, poorly de- fined muscle spot and narrow area concentric to free margins. Punctae coarser around muscle spot, becoming finer toward free margins. Material.-One complete carapace and one right valve from the McCann Hill Chert. Measurements.-The complete carapace is 1.70 mm long, 1.25 mm high, and 0.85 mm wide. Types. - Figured specimens, USNM 173791, 173792. Discussion.-The specimens from the McCann Hill Chert differ from Neoaparchites? insericus from the Eifelian of the southern Urals as illustrated by Rozhdestvenskaya (1962, pl. 1, figs. 5a, g) in having a smooth muscle spot and in having a gradation from the center to the margins in the size of the punctae. N.? insericus has been removed from Punc- taparchites Kay, 19834, to which it was originally assigned by Rozhdestvenskaya, because Harris (1957, p. 261-263) has demonstrated that the type species of Punctaparchites, P. rugosus (Jones, 1858) was incorrectly oriented and is a podocopid. How- ever, N.? insericus is only questionably assigned to Neoaparchites Bouéek, 1986, because, although Bou- Gek (1936, p. 39) stated that Neoaparchites was pro- posed for species of Aparchites with rounded cardi- nal angles, the original illustration and description of the type species, Primitia obsoleta Jones and Holl, 1865, indicate the presence of an obtuse but well- developed posterior cardinal angle. Further study of Neoaparchites obsoletus is required to clarify the characteristics of the genus. Occurrence.-USGS collections 6492-SD, 7032- SD from the McCann Hill Chert, Eagle (D-1) quad- rangle, Alaska. Genus APARCHITES Jones, 1889 "Aparchites" sp. aff. "A." auriculiferus Rozhdestvenskaya, 1962 Plate 10, figures 13, 14 Aparchites auwriculiferus Rozhdestvenskaya, 1962, p. 171- 172, pl. 1, figs. la, b; 2a, b. Description. outline subcircular ; dorsum straight, forming chord across circular outline of free margins. Hinge slightly incised ; cardinal angles obtuse but distinct. Valves equal; essentially no overlap on free margins. No marginal structures. Shell surface smooth. Material.-One incomplete carapace from the Mc- Cann Hill Chert. Measurements.-The single specimen is 1.85 mm long, 1.65 mm high, and 1.10 mm wide. SYSTEMATIC PALEONTOLOGY 29 Types.-Figured specimen, USNM 1737983. Discussion.-The specimen from the McCann Hill Chert appears to have a somewhat shorter hinge line than the specimens from the Eifelian beds of the southern Urals and western Bashkiria figured by Rozhdestvenskaya but is otherwise similar. Swartz (1969, p. 1238-1239), in restudying the type species of Aparchites, A. whiteavesi Jones, 1889, has sug- gested that the genus Aparchites be restricted to those species, that resemble the type species in hav- ing inward bending and thickening of the free mar- gins. This type of marginal structure is not present in "A." awriculiferus nor in the probably related species "A." chuchlensis PFibyl, 1952. These species appear to constitute a new genus in the Paraparchi- tacea, but additional material is necessary before such a genus is described. Occurrence.-USGS collection 7032-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Superfamily KLOEDENELLACEA Ulrich and Bassler, 1908 Family KLOEDENELLIDAE Ulrich and Bassler, 1908 Genus EUKLOEDENELLA Ulrich and Bassler, 1923 Eukloedenella recta n. sp. Plate 11, figures 19-24 2Eukloedenella sp., Copeland in Norris, 1967a, p. 138; Cope- land in Ludvigsen, 1970, p. 426 [part]. Description. outline subovate to subquad- rate, amplete to slightly postplete; dorsal outline of heteromorphic carapace subtriangular ; teenomorphs lanceolate in dorsal view. Dorsal and ventral mar- gins subparallel; anterior margin evenly rounded ; posterior margin straight to slightly convex. Pos- terior cardinal angle curved, but projection of dorsal and posterior margins meeting at about 90°. Essen- tially equivalved, but right valve overlaps left slightly around free margins. Stragulum on right valve overlaps left valve from anterior cardinal angle to midlength of carapace; hinge behind stragu- lum slightly incised. Greatest height and length near midpoint of carapace; greatest width posterior. S2 deep, elongated, pitlike. No indication of S1. Surface with some punctae or smooth. Material.-Four specimens from the Michelle For- mation; 1 carapace and 10 single valves from the McCann Hill Chert. Measurements.-The three figured carapaces from the Michelle Formation are 0.95 mm long, 0.60 mm high, and 0.52 mm wide; 0.80 mm long, 0.50 mm high, and 0.42 mm wide; 0.90 mm long, 0.60 mm high, and 0.50 mm wide, respectively. Types.-Holotype, GSC 294438; paratypes, GSC 29444, 29445, 29446, USNM 173794, 173795. Discussion. of the specimens are hetero- morphic; a few teecnomorphic single valves are less abruptly truncated posteriorly in dorsal view and have a more lanceolate outline. Hukloedenella recta belongs to the group of E. umbilicata Ulrich and Bassler, 1923, the type species of the genus. How- ever, it differs from other species assigned to this group by Ulrich and Bassler (1923, p. 669-671) by its wide, truncated dorsal outline and right-over-left overlap. E. dalhousiensis Copeland, 1962 is also simi- lar to E. recta, but according to Copeland (1962, p. 42, pl. 10, figs. 2, 3) the stragulum of E. dalhousien- sis is narrow and on the left valve, although the right valve has a slight angulation over the left im- mediately above the median sulcus. The specific name of E. recta refers to the straight or rectangular outline of the species. Occurrence.-Ludvigsen collections II-10, II-11 from the Michelle Formation, Blackstone River, Yu- kon Territory; USGS collections 7032-SD, 7033-SD, 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Eukloedenella soloensis n. sp. Plate 11, figure 28 Eukloedenella sp., Copeland in Ludvigsen, 1970, p. 426 (part). Description.-Lateral outline subovate, postplete, with strong posterior inflation extending above hinge line. Posterior margin more broadly rounded than anterior. Slight indication of S1. S2 anterior of midvalve (1.0 mm from anterior end), deep, slitlike, not extending to dorsum. Posteroventral margin flattened, flangelike. Surface finely punctate. Interior showing fold of S1 and well-defined subovate depres- sion of L2. Material.-One heteromorphic? right valve. Measurements.-The type specimen is 2.30 mm long and 1.50 mm high. Type.-Holotype, GSC 29442. Discussion.-This species is similar in lateral out- line to Eukloedenella sulcifrons Ulrich and Bassler, 1923, as emended by Swartz (1983, female speci- mens, pl. 30, 6a, d) but the sulcus of E. soloensis is more slitlike and the surface is punctate. Swartz (1933, p. 258) indicated that some specimens of E. sulcifrons have "a suggestion of a shallow undefined anterior sulcus" like that present on E. soloensis. E. punctillosa Ulrich and Bassler, 1923, is also similar to E. soloensis in lateral outline but is more regularly punctate and has a deeper sulcus. E. soloensis is un- usually large for a species of Eukloedenella. Occurrence.-Ludvigsen collection V-3, from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. 30 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY Genus POLONIELLA Giirich, 1896 Subgenus FRAMELLA Weyant, 1968 Poloniella (Framella) sp. aff. P. (F.) scheii Weyant, 1968 Plate 11, figures 25-27 Poloniella (Framellao) scheii Weyant, 1968, p. 1083-104, pl. 1, figs. 4, 5. Description.-Liateral outline amplete to slightly preplete. Dorsal margin in lateral view slightly sinu- ous to straight; anterior margin smoothly curved ; ventral margin weakly concave; posterior margin more sharply curved than anterior margin. Narrow marginal sulcus connects dorsally with S1 and pos- teroventrally with $3. S1 about half height of valve, narrowed ventrally, inclined anteriorly; S2 also about half height of valve, narrow, more slanted anteriorly than S1; S3 arcuate, concave anteriorly, extending from dorsal margin nearly to ventral mar- gin where it connects with marginal sulcus. L1 ovate in outline; L2 sinuous, narrow ventrally, slanted anteriorly and with a dorsoposterior extension; L3 large, slanted anteriorly, curved posteriorly, with narrow, shallow diagonal groove inclined anteriorly ; L4 crescentic, narrow, concave anteriorly. Surface smooth. Stragular process poorly developed. Hetero- morph not known. Material.-Five specimens, comprising four left and one right tecnomorphic valves, from the Mc- Cann Hill Chert. Measurements.-Two figured specimens are 0.60 mm long and 0.30 mm high, and 0.67 mm long and 0.35 mm high, respectively. Types.-Figured specimens USNM 178796, 173797, 173798. Discussion.-These specimens are most like the tecnomorphs of Polomiella (Framella) scheii de- scribed and illustrated by Weyant (1968, p. 103, pl. 1, fig. 5), from the lower part of the Blue Fiord Formation of Ellesmere Island. However, the speci- mens from the McCann Hill Chert differ from Wey- ant's specimens in the presence of the diagonal groove on L3. Occurrence.-USGS collection 7037-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Order PODOCOPIDA Miller, 1894 Suborder PODOCOPINA Sars, 1866 Superfamily BAIRDIACEA Sars, 1888 Family BAIRDIIDAE Sars, 1888 Genus BAIRDIA M'Coy, 1844 Bairdia sp. cf. B. leguminoides Ulrich, 1891 Plate 11, figures 10, 11 Bairdia leguminoides Ulrich, 1891, p. 197, pl. 17, figs. 5a- c; (for a complete synonymy see Sohn, 1960 [1961], p. 29). Description.-Carapace elongate, spindle-shaped, with short straight hinge line and dorsally inclined acuminate ends prolonged as spines on larger left valve. Posterior end more acute. Left valve overlaps right all around. Dorsal and ventral borders convex. Both valves inflated, maximum thickness near middle of valve. Surface smooth, possibly with some punc- tae. Material.-Two specimens from the Prongs Creek Formation, three specimens from the McCann Hill Chert. Measurements.-The figured specimen from the Prongs Creek Formation is 1.20 mm long and 0.50 mm high; the figured specimen from the McCann Hill Chert is 1.15 mm long, 0.55 mm high, and 0.45 mm wide. Types.-Figured specimens, GSC 29508, USNM 173799. Discussion.-The specimens from the McCann Hill Chert have a longer hinge than the holotype of Bair- dia leguminoides Ulrich, 1891 (USNM 41788), and also appear to have a slight ventral flattening. They differ from B. mucronata Rozhdestvenskaya, 1960, in lacking a marked ventral overlap, and differ from B. emaciata Kesling and Kilgore, 1952, in being less elongate. Occurrence.-Ludvigsen collections V-3 and V-5 from the Prongs Creek Formation, Solo Creek, Yu- kon Territory; USGS collections 7082-SD, 7 08T-SD, and 7038-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Bairdia dejecta n. sp. Plate 11, figures 1-4 Description.-Lateral outline bairdioid; dorsum curved; dorsoanterior margin long and nearly straight; dorsoposterior margin short and concave; ventroanterior and ventroposterior margins gently curved; ventral margin slightly concave. Carapace narrow and fusiform in dorsal outline. Left valve overlaps right all around. Dorsoanterior and dorso- posterior margins of left valve prolonged as down- ward slanting spines. Shell surface smooth. Material.-One complete and one broken carapace from the McCann Hill Chert. Measurements.-The holotype is 1.40 mm long, 0.55 mm high, and 0.40 mm wide. Types. - Holotype, USNM 173800; USNM 173801. Discussion.-This species differs from other spe- cies of Bairdia in having the terminal spines di- rected obliquely downward rather than upward as in the group of Bairdia legumincoides Ulrich, 1891. The specific name refers to the downcast appearance of the specimens. paratype, SYSTEMATIC PALEONTOLOGY 31 Occurrence.-USGS collection 7037-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Genus RECTOBAIRDIA Sohn, 1961 Rectobairdia sp. Plate 11, figure 15 Description.-Lateral outline bairdioid; dorsum straight, more than half length of valve. Dorsoan- terior margin concave, meeting smoothly curved ventroanterior margin at an angle above midheight of valve. Ventral margin slightly concave. Dorsopos- terior margin concave, meeting smoothly curved ventroposterior margin at an acute angle about mid- height of valve. Dorsal outline of valve smoothly curved. Surface smooth. Material.-One left valve from the McCann Hill Chert. Measurements.-The figured specimen is 1.20 mm long and 0.52 mm high. Types.-Figured specimen, USNM 173802. Discussion.-The long straight dorsum indicates that this specimen should be assigned to the genus Rectobairdia Sohn, 1961. Occurrence.-USGS collection 6492-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Genus BAIRDIOLITES Croneis and Gale, 1939 Bairdiolites? sohni n. sp. Plate 11, figures 5, 6, 9 Description.-Lateral outline fusiform; dorsum curved. Dorsoanterior and dorsoposterior margins straight to slightly concave; ventroanterior margin gently curved; ventral margin straight to slightly convex ; ventroposterior margin nearly straight. Left valve overlaps right all around. Anterior and pos- terior ends sharply acuminate, extended as spines on larger left valve. Both valves with vertical shoulders or ridges on anterior and posterior quarters. Dorsal outline subfusiform, with parallel sides. Surface smooth. Duplicature well developed. Muscle scar round. Material.-One carapace and three valves, all from the McCann Hill Chert. Measurements.-The holotype is 1.25 mm long, 0.47 mm high, and 0.40 mm wide. Types.-Holotype, USNM 173803; USNM 173804, 173805, 173806. Discussion. -Bairdiolites? sohni superficially re- sembles Bairdia leguminoides Ulrich, 1891, because of its acuminate or spinose ends, but differs in hav- ing the two characteristic vertical ridges and a more rounded dorsum. This species is only questionably paratypes, assigned to Bairdiolites because the other described species of Bairdiolites lack the very acuminate ends of B.? sohni. Bairdiolites has previously been con- sidered to range from the Late Mississippian into the Early Pennsylvanian (Sohn, 1960 [1961], p. 69- 70) ; however, two Middle Devonian species illus- trated by Rozhdestvenskaya (1962, pl. 21, figs. Sa-v, 4a-b), Bairdia transversocostata Rozhdestvenskaya, 1962, and Bairdia navicula Martinova and Polenova, 1955, may belong in Bairdiolites rather than Bairdia. Occurrence.-USGS collections 6492-SD, 7037- SD, from the McCann Hill Chert, Eagle (D-1) quad- rangle, Alaska. Genus NEWSOMITES Morris and Hill, 1952 Newsomites? sp. Plate 14, figures 17, 18 Description. outline ovate, preplete; dorsum gently curved; anterior margin broadly rounded; ventral margin gently curved; posterior margin sharply curved. Dorsal outline oval; maxi- mum width median. Hinge incised ; larger left valve overlaps anterior and posterior ends of right valve. In end view, carapace tumid and asymmetrical ; left valve markedly larger than right, overlaps and over- reaches right ventrally. Surface smooth. Material.-One carapace from the McCann Hill Chert. Measurements.-The figured specimen is 0.47 mm long, 0.32 mm high, and 0.40 mm wide. Types.-Figured specimen, USNM 178847. Discussion.-The preplete lateral outline suggests that this may be a juvenile specimen. The normal pore canals reported by Lundin and Newton (1970, p. 33, 34) for Newsomites pertumidus Morris and Hill, 1952, and N. profusus Lundin and Newton, 1970, have not been observed in the specimen from the McCann Hill Chert; they have probably been obliterated by this type of silicification. Although Newsomites was originally described from the Silu- rian of the Eastern United States, Polenova (1968, p. 72-74) has included in this genus a species and three subspecies from the Devonian of Siberia, ex- tending its range to Middle Devonian. Occurrence.-USGS collection 7087-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Family BEECHERELLIDAE Ulrich, 1894 Genus ACANTHOSCAPHA Ulrich and Bassler, 1923 Acanthoscapha sp. Plate 11, figures 12-14 Description. outline subfusiform; dor- sum long, slightly concave at either end, terminat- ing in spines; anterior margin more sharply curved 32 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY than posterior margin; ventral margin slightly con- cave. Hinge line more than half length of carapace; left valve slightly overreaches right dorsally and overlaps right in ventral concavity. Anteroventral and posteroventral margins of both valves meet as flattened flange. Posterior terminal spine on left valve nearly parallel to hinge line, anterior terminal spine inclined slightly upward. Dorsal outline fusi- form. Shell surface smooth. Material.-One poorly preserved carapace from the McCann Hill Chert. Measurements.-The figured specimen is 1.25 mm long, 0.35 mm high, and 0.32 mm wide. Types.-Figured specimen, USNM 173807. Discussion.-This single carapace is close to Acan- thoscapha navicule (Ulrich, 1891) from the Kalk- berg Limestone of eastern New York, but is too poorly preserved to identify specifically. Occurrence.-USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Genus SHIDELERITES Morris and Hill, 1951 Type species.-Shidelerites typus Morris and Hill, 1951. Species included.-Shidelerites yukonensis n. sp. Revised diagnosis. - Asymmetrical beecherellid ostracodes with upright or posteriorly slanted spine on anterodorsal end of larger left valve, acuminate posterior, and laterally compressed anteroventral and posteroventral marginal areas. Discussion.-Morris and Hill (1951, p. 698) ori- ented Shidelerites with the anterior spine pointed downward in an anteroventral position, and com- pared the genus to the Cypridinidae but noted that it lacks the opening for protrusion of the anterior appendages characteristic of that family. Later, Triebel (1961, p. 347-348) examined topotype speci- mens and suggested that the genus should be reori- ented so that the spine is anterodorsal in position and the sinuous margin is ventral. He proposed a revised diagnosis for Shidelerites (Triebel, 1961, p. 348) which is freely translated as follows: Carapace middle sized, without distinct sculpture, spindle- shaped in dorsal outline, elongated in lateral view, height less than half length. Anterior end broadly rounded, posterior end drawn out into a sharp process that is somewhat below the straight hinge line. Dorsal margin of left valve with a triangular upward-pointing process on the anterior, which is lacking on the right (valve). Ventral margin slightly bent in before the middle, projecting to the ends in flat arcs. Carapace in these parts somewhat compressed, in the remaining (parts) approximately evenly arched. Left valve larger than right, very widely overreaching at the antero- dorsal margin with its triangular process, less overreach- ing on the remaining dorsal margin, somewhat overlapping ventrally in the oral region. Along the anterior margin and the terminal part of the ventral margin the valves lie simply together. Inner characters unknown. Triebel (1961, p. 349) noted that Shidelerites had been tentatively referred to the Bairdiidae by Betty Kellett Nadeau (note in Morris and Hill, 1951, p. 699) and stated that no better classification could be made until the internal characters of the valves were known. Having noted the resemblance of Shidelerites to Acanthoscapha Ulrich and Bassler, 1923 (-=Al- lanella Boulek, 1936; see Berdan, 1960, p. 471), Triebel (1961, p. 349) concluded that Acanthoscapha also should be assigned to the Bairdiidae rather than the Beecherellidae. His reasons for removing Acan- thoscapha from the Beecherellidae were based on the flattened venter of Beecherellao as opposed to the laterally compressed ventral margins of Acantho- scapha, the hollow ventroterminal spines of Beech- erelle as opposed to the dorsoterminal spines of Acanthoscapha, and the resemblance of Acantho- scapha to Bairdia. In our opinion, the flattened venter of Beecherella should not be considered a family characteristic, because this feature appears at ran- dom in otherwise unrelated stocks. Acanthoscapha may well be ancestral to Bairdia, but should be re- tained in the Beecherellidae because of its long straight hinge line and attenuated outline. In addi- tion to Shidelerites, Scaphina Polenova, 1968 and Celechovites Pokorny, 1950, should be included in the Beecherellidae, as suggested by Polenova (1968, p. 54). These genera all resemble Beecherellao in having a long straight hinge line and height less than half the length of the valves. To facilitate comparison with Shidelerites yukon- ensis n. sp., the holotype (USNM 116420) and a paratype (USNM 116421la) of Shidelerites typus Morris and Hill, 1951, are illustrated with the re- vised orientation on plate 11, figures 16, 17. Geologic range.-Waldron Shale (Middle Silurian) of Indiana; Prongs Creek Formation (Lower Devo- nian) of Yukon Territory. Shidelerites yukonensis n. sp. Plate 11, figure 18 Description.-Carapace elongate in lateral view, acuminate at each end ; fusiform in dorsal view ; oval in end view. Left valve larger than right, overreach- ing it dorsally and overlapping it midventrally and posteroventrally. Greatest height in posterior half, excepting anterior spine; greatest length in dorsal half. Hingeline straight, in anterior three-fourth of valve. Posterodorsal margin sloping ventrally to acuminate posterior cardinal corner, slightly con- cave; posteroventral margin evenly curved to mid- venter. Ventral margin concave at midlength, curv- SYSTEMATIC PALEONTOLOGY 33 ing smoothly into anteroventral and posteroventral margins. Anteroventral margin gently curved to meet vertical anterior margin. Anterior cardinal angle of right valve with slight dorsal angulation; anterior cardinal angle of left valve wrapped around that of right valve and produced into strong ver- tically directed spine or horn. Lateral surface smooth; anteroventral and posteroventral areas slightly concave parallel with the free margin, an- teroventral area apparently larger. Internally, dupli- cature visible through hole in left valve continuous at least in posterior half of valve as fine shelflike thickening of free margin. Material. -One complete carapace from the Prongs Creek Formation. Measurements.-The holotype is 1.55 mm long and 0.60 mm high. « Types.-Holotype, GSC 29440. Discussion. -Shidelerites yukonensis differs from S. typus Morris and Hill, 1951, the type species of the genus, in having the anterior margin nearly ver- tical rather than smoothly curved, and in having the anterodorsal spine erect rather than slanted pos- teriorly. Occurence.-Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory. Genus BEECHERELLA Ulrich, 1891 Beecherella? sp. Plate 11, figures 7, 8 Description. outline subtrapezoidal ; both ends acuminate; greatest length ventral; greatest height in anterior quarter. Hinge line straight, not parallel to ventral margin, sloping slightly posteri- orly. Venter flat, extended laterally as ala with minute posteriorly directed spine. Dorsal outline sub- triangular. Shell surface smooth. Duplicature poorly developed. Material.-One right valve from the McCann Hill Chert. Measurements.-The figured specimen is 0.55 mm long, 0.25 mm high, and 0.25 mm wide. Types.-Figured specimen, USNM 173808. Discussion. -This single right valve is suggestive of Beecherella in its lateral outline and flattened venter, but the relatively short hinge, poorly devel- oped duplicature, and wide alate process are not typical of the genus Beecherella as represented by the type species, B. carinata Ulrich, 1891. The flat- tened venter and alate process are like similar struc- tures developed in the genus Pseudocyproides Mor- ris and Hill, 1952, but the type species of this genus, P. alatus, is described by Morris and Hill (1952, p. 16, pl. 1, fig. 4) as having a strongly arched dorsum. Examination of the holotype of P. alatus Morris and Hill, 1952 (USNM 123230) suggests that the resem- blance is homeomorphic. Occurrence.-USGS collection 7037-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Superfamily CYPRIDACEA Baird, 1845 Family UNCERTAIN Genus CAMDENIDEA Swain, 1953 Camdenidea sp. Plate 13, figures 1-4 Description. -Lateral outline subreniform ; dorsal margin smoothly curved, merging with more sharply curved anterior margin; ventral margin straight to concave; posterior margin acuminate. Dorsal outline subelliptical. Right valve overlaps left around free margins; left valve with crescentic depressed areas on anterior and posterior margins which are absent on right valve. Surface smooth. Duplicature narow. Material.-Two left valves, one right valve, and one carapace from the McCann Hill Chert. Measurements.-The carapace is 0.55 mm long, 0.27 mm high, and 0.32 mm wide. Types.-Figured specimens, USNM 173812, 173813, 173814. Discussion. small specimens differ from Camdenidea camdenensis Swain, 1953, the type spe- cies of the genus, in having the right valve larger than the left and in having anteroventral and pos- teroventral compressed areas on the left valve only. A formal name is not proposed for them here be- cause of the probability that they are immature individuals. Occurrence.-USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Superfamily indet. Family TRICORNINIDAE Blumenstengel, 1965 Genus TRICORNINA Boutek, 1936 "Tricornina" caurina n. sp. Plate 12, figures 1-3 Description. - Carapace boat-shaped; greatest length along dorsal margin; posterior cardinal angle acuminate; posteroventral margin sloping to rela- tively straight ventral margin; anterior cardinal angle more than 90°, anterior margin broadly rounded. Anterior and posterior margins with nar- row marginal flange. Surface smooth, evenly curved from lateral margins to very long hollow spine at midvalve. Spine base large, diameter about three- quarters height of valve; spine extending at right angles to valve, tapering distally with slight dorsal and posterior swing. 34 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY Material.-One right valve from the Prongs Creek Formation. Measurements.-The holotype is 1.35 mm long and 0.60 mm high. The spine is 0.85 mm long. Types.-Holotype, GSC 29448. Discussion.-The size and orientation of the lat- eral spine of this species is extremely distinctive. The anterodorsal corner of the valve is slightly broken so it is impossible to determine if an antero- dorsal spine or projection should be present. Occurrence.-Ludvigsen collection V-3, from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. Tricornina sp. Plate 12, figure 4 Description.-Valve boat-shaped; dorsal margin greatest length ; posterior angle acuminate; anterior angle with strong, dorsally directed spine. Surface smooth, with long straight only slightly tapering spine near midventral part of valve. Spine projects posterolaterally at about 45° to the valve surface. Material.-One small incomplete (now broken) left valve from the Michelle Formation. Measurements.-Specimen broken, not measured. Types.-Figured specimen, GSC 29510. Discussion.-This specimen is too poorly preserved for adequate comparison with other tricorninids. It has the general features of the genus. Occurrence.-Ludvigsen collection I-3 from the Michelle Formation, Hart River, Yukon Territory. Genus BICORNINA Jordan, 1964 Bicornina sp. Plate 12, figures 5-7 Description.-Lateral outline boat-shaped ; dorsal margin straight to slightly convex; free margins smoothly curved. Anterior cardinal angle acute, pro- duced as spine on larger left valve; posterior cardi- nal angle blunt or rounded. Dorsal outline arrow- shaped ; posteroventral half of both valves occupied by large hollow spine which projects posteriorly and curves dorsally, extending beyond posterior margin of carapace. Shell surface smooth. No duplicature. Material.-One broken, poorly preserved carapace, two left valves, and one right valve from the Mc- Cann Hill Chert. Measurements.-The figured left valve is 0.65 mm long without theanterior spine and 0.35 mm high. The length, including both spines, is 0.85 mm. Types.-Figured specimens, USNM 173809, 173810. Discussion.-Jordan (1964, p. 58-59) distin- guished Bicornina from Tricorninae Boucek, 1936 on the basis that Bicornina lacks the posterodorsal spine of Tricornina. The blunt posterior angle of the spe- cimens from the McCann Hill Chert suggests that they belong in Bicornina. Occurrence.-USGS collections 6492-SD, 7032- SD, 7037-SD, 7038-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Family BEROUNELLIDAE Sohn and Berdan, 1960 Genus BEROUNELLA 1936 Berounella sp. aff. B. minuta Blumenstengel, 1970 Plate 12, figures 8, 9 Berounellao minuta Blumenstengel, 1970, p. 19-20, pl. 1, figs. 10, 11. Description.-Lateral outline subtrapezoidal ; dor- sal margin straight to slightly concave ; ventral mar- gin straight, parallel to dorsal margin ; anterior mar- gin slightly sinuous ; posterior margin concave, curyv- ing posteriorly parallel to dorsal margin. Posterior end of valve drawn out into long hemitube character- istic of genus. Valve trilobate; L1 nearly vertical, extending from anterodorsal to anteroventral mar- gins of valve; L2 knoblike, anteromedian in position ; L3 curved obliquely forward. L3 with long hollow spine arising from ventral part and projecting pos- teriorly and slightly dorsally. Small spine at mid- height of posterior margin. Three, possibly four, small digitate spines on anterodorsal part of anterior margin. Anteroventral and posteroventral margins slightly flattened. Duplicature best developed on anterior and posterior margins. Material.-One right valve from the McCann Hill Chert. Measurements.-The figured specimen is 0.95 mm long, including the spine, and 0.30 mm high. Types.-Figured specimen, USNM 173811. Discussion.-The single right valve from the Mc- Cann Hill Chert resembles Berownello minuta Blu- menstengel, 1970, in having a long prominent spine on L3, which is apparently not as well developed, if present, on the other species of Berounella listed by Blumenstengel (1965, p. 56). However, our specimen differs from B. minuta in the arrangement of the anterodorsal spines. Blumenstengel (1970, p. 19, pl. 1, fig. 10) described and illustrated B. minuta as having a prominent anterodorsal spine which curves upward and forward, and a second smaller spine beneath this. Our specimen has three short spines on the anterodorsal part of the anterior margin. A fourth may have been present and then broken off, but it could not have been as prominent as the an- terodorsal spine shown by Blumenstengel. f Occurence.-USGS collection 7037-SD, from the - McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. SYSTEMATIC PALEONTOLOGY 85 Suborder METACOPINA Sylvester-Bradley, 1961 Superfamily HEALDIACEA Harlton, 1933 Family BAIRDIOCYPRIDIDAE Shaver, 1961 Genus BAIRDIOCYPRIS Kegel, 1932 Bairdiocypris? sp. cf. B.? cordiformis Rozhdestvenskaya, 1959 Plate 12, figures 10, 11 Bairdiocypris(?) cordiformis Rozhdestvenskaya, 1959, p. 167, | pl. 25, figs. 1a, b; 2a, b. Description. -Carapace reniform to heart-shaped ; greatest length in ventral third; greatest height slightly anterior of midlength. Left valve overlaps right along dorsal margin; greatest overlap postero- dorsal. Right valve with low marginal flange at anteroventral and posteroventral corners; flange not present midventrally where both valves are slightly concave. ' Material.-One carapace from the Prongs Creek Formation and one from the McCann Hill Chert. Measurements.-The specimen from the Prongs Creek Formation is 0.90 mm long and 0.70 mm high. Types.-Figured specimens, GSC 29450, USNM 173840. Discussion.-The figured specimens are very simi- lar to Bairdiocypris? cordiformis from the Biya beds (Eifelian) of Bashkiria; the Yukon specimen, how- ever, has its greatest height slightly anterior of mid- valve, that of B.? cordiformis is slightly posterior of midvalve. Occurrence.-Ludvigsen collection V-3 from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory; USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Bairdiocypris sp. Plate 12, figure 12 "Bythocypris" sp., Copeland in Norris, 1967a, p. 128, 130, 138, 140, 141. Description.-Carapace subovate in lateral view, slightly concave midventrally, regularly convex dor- sally. Left valve overlapping right along all mar- gins; least overlap at anteroventral margin. Hinge curved, about one-third greatest length, inclined pos- teroventrally, and situated in posterior half of valve. Surface smooth. Material.-More than 10 specimens from the Prongs Creek Formation. f ___ Measurements.-The figured specimen is 1.20 mm long and 0.80 mm high. Types.-Figured specimen, GSC 29476. Discussion.-Some variation in overlap occurs in this species, some specimens showing more left-over- right overlap posteroventrally. In general, however, the greatest overlap is as indicated above. Occurrence.-Ludvigsen collections V-3, V-4, V-5, _Prongs Creek Formation, Solo Creek, Yukon Terri- tory. _ Genus KURESAARIA Adamczak, 1967 Kuresaaria blackstonensis n. sp. Plate 12, figures 13-25 Bairdiocypris sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 8 [imprint 1967]; Copeland in Ludvigsen, 1970, p. 426 (part). Description.-Carapace subovate to subtriangular in lateral view; anterior and posterior margins evenly rounded; dorsal margin highly arched ; ven- tral margin convex. Carapace fusiform in dorsal view. Left valve larger than right, overlapping right all around; greatest overlap along dorsum and venter. Valves moderately convex, smooth ; greatest thickness median in ventral half. Hinge straight, sloping posteriorly, about one-half greatest length of valve, consisting of simple groove and ridge hinge- ment. Left valve with contact groove terminating in two ventral stop ridges, not present midventrally. Right valve more angular than left. Hinge of right valve prominent, with abrupt terminal angulations ; anterior margin extended ventrally, ventral margin sloping upward to regularly curved posterior mar- gin. Muséle sear on median inner surface, circular in outline but less distinct on its dorsal edge, appar- ently consisting of numerous small sears. Shell very thick. Material.-Nine specimens from the Michelle For- mation ; three specimens from the Prongs Creek For- mation; more than 90 specimens from the McCann Hill Chert. Measurements.-Three left valves from the Mi- chelle Formation are 1.35 mm long and 0.95 mm high, 1.02 mm long and 0.70 mm high, and 1.10 mm long and 0.75 mm high, respectively. Two right valves from the Michelle Formation are 1.32 mm long and 0.80 mm high, and 1.25 mm long and 0.78 mm high, respectively. Types.-Holotype, GSC 29487; paratypes, GSC 29488, 29489, 29490, 29491, 29492, 29493, USNM 170343, 173815, 173816, 173817, 173818. Discussion.-This species is considered to belong in Kuresaaria because of the character of the con- tact groove and ventral stop ridges, although the hinge is straighter than that of typical Kuresaaric. It differs from K. gotlandica Adamczak, 1967, the type species of the genus, in having the greatest height more median and lacking the shallow antero- dorsal depression of K. gotlandica. An unusually thick shell has been demonstrated for K. gotlandica by Adamczak (1967, figs. 3C, D) ; this condition pre- vails in K. blackstonensis also. One specimen (pl. 12, fig. 23) from the McCann Hill Chert, which is im- perfectly silicified, shows structures that appear to be siliceous fillings of small pore canals in the shell 36 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY wall. These are smaller and more closely spaced than those of the pachydomellids. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, 7087-SD, and 7038-SD from the Mc- Cann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collections II-10, II-13, II-14, and IV-3 from the Michelle Formation, Blackstone River, Yu- kon Territory; Ludvigsen collection V-3 from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. Genus BAIRDIOHEALDITES McGill, 1968 Bairdiohealdites? scapulatus n. sp. Plate 13, figures 8-11 Description.-Lateral outline subreniform ; dorsal outline sublanceolate. Dorsal margin smoothly curved, sloping abruptly into short, straight postero- dorsal margin; posteroventral margin sharply curved ; ventral margin straight to slightly concave; anterior margin sharply curved, merging smoothly into gently curved anterodorsal slope. Left valve overlaps right around free margins, overreaches right along straight hingeline. Greatest height me- dian to posteromedian; greatest width in posterior third of carapace. Shoulderlike swelling or ridge on posterodorsal third of both valves, most prominent on right valve. Lateral surface of both valves flat- tened anterior to shoulder. Surface smooth. Muscle scar median to anteromedian in position, round, com- posed of many small flecks. Marginal structures not observed. Material.-More than 15 specimens from the Mc- Cann Hill Chert. Measurements.-The holotype is 1.60 mm long, 1.00 mm high, and 0.80 mm wide (maximum width through shoulders). Types.-Holotype, USNM 173819; paratypes, USNM 173820, 173821, 173822, 173823, 1783824. Discussion.-This species is questionably assigned to Bairdiohealdites because of its overlap and out- line, especially the abrupt posterodorsal slope, and because of the distinct circular muscle scar, which was noted by McGill (1967, p. 1080) in the type species of the genus, B. rozhdestvenskayae. Bairdio- healdites? seapulatus, however, differs from other species referred to the genus in having a distinct posterodorsal shoulder. Although this character sug- gests a relationship to Condracypris Roth, 1929, Lundin (1968, p. 57-59) has noted that Condracypris has a duplicature, a structure that is lacking in B.? scapulatus. Furthermore, species assigned to Con- dracypris characteristically have the greatest height anterior to the midlength, whereas in B.? scapulatus the greatest height is posterior to the midlength. Lundin (1968, p. 58) does not consider the elongate nodes of Condracypris binoda Roth, 1929, the type species of the genus, to be a generic character. It appears likely that these features may develop in other genera. The specific name of B.? scapulatus refers to the posterodorsal shoulder characteristic of the species. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, and 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Genus PRAEPILATINA Polenova, 1970 Praepilatina sp. aff. P. praepilata sibirica Polenova, 1970 Plate 13, figures 5-7 Description. - Lateral outline subsemicircular; dorsal margin nearly a semicircle; posterior margin steeply inclined ; ventral margin straight to slightly concave; anterior margin sharply rounded. Left valve apparently overlaps right ; posteroventral mar- gin of left valve sharply rounded; posteroventral margin of right valve extended as small spine or angulation. Valves evenly convex in dorsal view. Sur- face smooth. Material.-About 12 valves, many broken, from the McCann Hill Chert. Measurements.-The two figured right valves are 0.75 mm long and 0.50 mm high, and 0.75 mm long and 0.50 mm high, respectively. The figured left valve is 1.10 mm long and 0.85 mm high. Types.-Figured specimens, USNM 173825, 173826, 173827. Discussion.-This form appears to be most simi- lar to Praepilatina praepilata sibirica from the Lower Devonian of the Altai-Sayan region of Siberia as illustrated by Polenova (1970, pl. 24, figs. 3, 5 ) in the posteroventral projection of the right valve. Polenova (1970, p. 49) distinguished P. praepilata - sibtrica from P. praepilata praepilato (Polenova, 1960), the type species, on the basis that the left valve showed more dorsal overlap in P. p. sibirica. Unfortunately, we have no carapaces and hence can- not determine the degree of overlap; however, fig- ures of P. p. praepilata (Polenova, 1960, pl. 8, fig. 5; 1970, pl. 24, fig. 2) show a rounded rather than acuminate posteroventral margin. Occurrence.-USGS collections 7037-SD, 70838- SD from the Eagle (D-1) quadrangle, Alaska. The holotype of P. p. sibirica is from the Lower Devo- nian upper Krekov beds of the Salair district in Siberia. Family BARYCHILINIDAE Ulrich, 1894 Genus BARYCHILINA Ulrich, 1891 Barychilina? sp. Plate 14, figure 19 Description. - Valve subrhomboidal; hingeline straight; overlap unknown. Deep elongate sulcus ex- SYSTEMATIC PALEONTOLOGY 37 tending from dorsal margin about one-third the dis- tance to the ventral border. Shallow depression on anterodorsal corner; L1 broad, tumid. Surface of valves finely punctate with longitudinal ridges in posterior half, depressed areas between ridges finely reticulate. Material.-One right valve from the Michelle For- mation. Measurements.-The figured specimen is 0.90 mm long and 0.50 mm high. Types.-Figured specimen, GSC 29451. Discussion.-This species is very similar to Bary- chilina? opisthorhysa (Kesling and Kilgore, 1952), but has a shorter sulcus and finer reticulate posterior ridges. Occurrence.-Ludvigsen collection I-3 from the Michelle Formation, Hart River, Yukon Territory. Genus TRYPETERA Kesling, 1954 Trypetera? sp. Plate 14, figure 21 Description. margin straight; anterior margin smoothly curved; ventral margin gently curved; posterior margin broken. Deep round pit in anterodorsal part of right valve. Surface ornamenta- tion consisting of large round punctae. Material.-One broken right valve from the Mi- chelle Formation. Types.-Figured specimen, GSC 29447. Discussion.-This form is known only from the anterior part of a right valve. The identification of this specimen is extremely questionable but appears plausible on the basis of the description of Trypetera by Kesling (1954, p. 178). No direct comparison with Trypetera barathrota Kesling, 1954, is attempted. Occurrence.-Ludvigsen collection II-13 from the Michelle Formation, Blackstone River, Yukon Terri- tory. Family CAVELLINIDAE Egorov, 1950 Genus VORONINA Polenova, 1952 Voronina sp. cf. V. inventa Rozhdestvenskaya, 1962 Plate 13, figures 12-17 Description. -Lateral outline ovate; dorsal and ventral margins smoothly curved; anterior margin sharply curved; posterior margin bluntly subangu- late. Carapace markedly asymmetrical; right valve larger than left, overlaps it all around. Greatest over- lap dorsal; ventral overlap slightly less than dorsal overlap. Junction between lateral surface and mar- ginal overlapping surface of right valve bluntly sub- angular; low keel may be developed at junction dor- sally. Lateral surface of right valve flattened in end view; lateral surface of left valve smoothly convex. Dorsal and ventral margins of left valve nearly parallel; ends asymmetrically rounded, sharpest curve of anterior end ventral and sharpest curve of posterior end dorsal in position, so that lateral out- line of left valve approximates a parallelogram. In- terior of right valve with contact groove around free margins; hinge broken on only single valve (USNM, 173829) but apparently a simple sharp edge in right valve. Low swelling in anterodorsal half of right valve, anterior to which is possible oval muscle sear composed of large individual flecks. Exterior sur- face of valves smooth or finely punctate. Material.-T wo carapaces and a right valve from the McCann Hill Chert. Measurements.-The figured carapace (pl. 13, figs. 12-14) is 1.85 mm long, 1.35 mm high and 0.85 mm wide. Types.-Figured specimens, USNM 173828, 173829, 173880. Discussion.-This form is very close to Voromnina inventa Rozhdestvenskaya, 1962, but is apparently relatively shorter and higher. Rozhdestvenskaya (1962, p. 205) considered the right valve of V. in- venta to be larger than the left, the reverse of the orientation suggested by Polenova (1952, p. 140) for V. voronensis Polenova, 1952, the type species of the genus. The specimens from Alaska appear to agree with Rozhdestvenskaya's orientation for V. inventa, as the presumed muscle sear is anterior in position and the greatest width is postmedian. Tolmachoff (1926, p. 36) described Ellesmeria ovata, the type species of his genus Ellesmeria, as having the right valve larger than the left, with greater overlap dor- sally and ventrally than on the anterior and pos- terior ends; however, he also described E. ovata as having a shallow anterior sulcus on both valves, a feature which is not present in Voronina. Should the presence of a sulcus prove to be nondiagnostic for Ellesmeria, V. inventa Rozhdestvenskaya, 1962, and the Alaskan specimens might be considered to belong to Ellesmeria. Both Polenova (1952, p. 141) and Rozhdestven- skaya (1962, p. 205) described dimorphism in Voro- nina, the teenomorphs being flatter than the hetero- morphs in dorsal view. The specimens from' Alaska are considered to be heteromorphs by comparison with V. invenrta; no teenomorphic specimens have been found. Occurrence.-USGS collections 6492-SD and 7032-SD, from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Genus CAVELLINA Coryell, 1928 Subgenus INVISIBILA Polenova, 1960 Cavellina (Invisibila)? sp. Plate 14, figures 12-14 Description.-Lateral outline suboval ; dorsal mar- gin gently curved ; anterior and posterior ends evenly 38 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY rounded ; ventral margin straight or slightly concave. Carapace narrow in dorsal view. Sheil thin, shell sur- face smooth. Material. -One sheared carapace and one right valve from the McCann Hill Chert. Measurements.-The right valve of the carapace (USNM 173848) is 0.75 mm long and 0.40 mm high. Types.-Figured specimens, USNM 173848, 173849. Discussion.-The valves of the only carapace are sheared so that the character of the overlap and hingement cannot be determined. The general out- line of the valves, however, resembles that of Cavel- lina (Invisibile) porrecta Polenova, 1960 (p. 33-34, pI. 5, fig. 5). _ Occurrence.-USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Family PACHYDOMELLIDAE Berdan and Sohn, 1961 Genus TUBULIBAIRDIA Swartz, 1936 Tubulibairdia sp. Plate 14, figures 27-29 Description.-Liateral outline of carapace suboval ; dorsal margin broadly curved; anterior and pos- terior ends more closely curved; ventral margin gently curved to straight. Valves unequal ; left valve overlaps right on free margins, narrowly on anterior and posterior ends and broadly ventrally, and over- reaches right slightly dorsally. Hinge incised, half or more length of valve. Surface smooth. Material.-One specimen from the Prongs Creek Formation; more than 15 specimens from the Mc- Cann Hill Chert. Measurements.-The figured specimen from the McCann Hill Chert is 1.25 mm long, 0.75 mm high, and 0.80 mm wide. Types.-Figured specimens, USNM 173831, GSC 29475. Discussion.-Most of the specimens of Tubulibair- dia from the McCann Hill Chert are noticeably poorly silicified in comparison to specimens of other genera in the same collections; some are steinkerns that show fillings of the characteristic tubules of Tubulibairdia. This poor preservation may be due to the coarsely porous character of the shell walls. The material at hand is not adequate to discriminate the species. Occurrence.-USGS collections 6492-SD, 7032- SD, 7033-SD, and 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska; Ludvigsen collection V-3, Prongs Creek Formation, Solo Creek, Yukon Territory. Pachydomellid indet. 1 Plate 14, figures 24-26 Description. and dorsal outlines of cara- pace subovate; anterior outline roughly heart- shaped. Valves asymmetrical ; left much larger than right, overreaching it dorsally and overlapping it ventrally and around ends. Hinge line deeply in- cised. Carapace very tumid; width greater than height, greatest width postmedian. Posterior of left valve with conspicuous compressed area; posterior of right valve also compressed, but not as much. Both anterior and posterior ends sharply rounded. Shell surface smooth or very faintly striatopuncetate. Material.-Two broken carapaces and nine left valves from the McCann Hill Chert. Measurements.-The figured carapace is 0.60 mm long, 0.40 mm high, and 0.45 mm wide. Types.-Figured specimens, USNM 178882, 173833. Discussion.-The pronounced asymmetry, incised hinge line, and thick shell suggest that these speci- mens belong in the Pachydomellidae, although the preservation is such that the characteristic tubules of that family cannot be seen. The compressed pos- terior of both valves and the tumidity are character- istic of the genus Newsomites Morris and Hill, 1952, which Lundin and Newton (1970, p. 33, 34) consider similar to the pachydomellids although retaining it in the Bairdiidae pending further study. However, species assigned to Newsomites, such as N. pertu- midus Morris and Hill, 1952, N. profusus Lundin and Newton, 1970, and N. notabilis (Polenova, 1955) have the greatest thickness median rather than post- median as in the pachydomellids and the specimens from the McCann Hill Chert. Occurrence.-USGS collections 6492-SD, 7032- SD, 7087-SD, and 7038-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Pachydomellid indet. 2 Plate 14, figure 23 Description.-Lateral outline suboval; dorsum curved; anterior end evenly curved ; ventral outline straight to gently convex; posterior end more acute than anterior. Hinge straight, incised. Surface cov- ered with spines, which are longest at ventral edge of lateral surface and shortest on flattened venter. Shell thick, apparently tubulous. Material.-T wo left valves from the McCann Hill Chert. Measurements.-The figured specimen is 0.55 mm long and 0.30 mm high. Types.-Figured specimen, USNM 173846. Discussion.-These specimens resemble the inter- SYSTEMATIC PALEONTOLOGY 39 nal molds of Tubulibairdia in which the shell is dis- solved and the traces of the filled tubules appear as spines. However, in these valves the shell is pre- served and appears to be tubulous, although the sili- fication obscures the structure. They may represent a Tubulibairdia-like form in which the setae which were presumably in the tubules became sheathed in spines, although the preservation is such that the spines do not appear to be hollow. Occurrence.-USGS collection 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Superfamily QUASILLITACEA Coryell and Malkin, 1936 Family QUASILLITIDAE Coryell and Malkin, 1936 Genus ERIELLA Stewart and Hendrix, 1945 Eriella? sp. Plate 14, figures 1, 2 Description.-Right valve subovate in lateral out- line; greatest height median; anterior and posterior margins equally rounded. Hinge long, nearly one- third the greatest length, situated near median and incised below dorsal shoulder. Surface coarsely re- ticulate, reticulae in concentric rows about a central reticulate area near midvalve; central pit, if present, the same size as surrounding reticulae. Material.-One right valve from the Michelle For- mation, four specimens from the McCann Hill Chert. Measurements.-The figured specimen from the Michelle Formation is 0.50 mm long and 0.30 mm high. Types.-Figured specimens, GSC 29452, USNM 173834. Discussion. -This species is smaller, more ovate and more coarsely reticulate than the type species, Eriella robusta Stewart and Hendrix, 1945, from the "Plum Brook Formation" of Ohio. The specimens from the McCann Hill Chert are somewhat more finely reticulate than the specimen from the Mi- chelle, and may not be conspecific. The figured right valve from the McCann Hill Chert has a small pos- teroventral spine as described for Eriella. Occurrence.-Ludvigsen collection I-3 from the Michelle Formation, Hart River, Yukon Territory; USGS collection 7037-SD, McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Superfamily THLIPSURACEA Ulrich, 1894 Family THLIPSURIDAE Ulrich, 1894 Genus NEOCRATERELLINA Krandijevsky, 1968 Neocraterellina? crescentifera n. sp. Plate 14, figures 5-11 Healdia sp., Berdan in Churkin and Brabb, 1968, table 1, pl. 4, fig. 1. [Imprint 1967.] Description. - Lateral outline ovate; dorsum smoothly curved; anterior margin sharply rounded ; ventral margin nearly straight to slightly convex; posterior margin smoothly curved. Left valve larger than right, overreaching it dorsally and overlapping it distinctly on posterior and ventral margins, over- lapping it narrowly on anterior margin. Dorsal out- line subovate; hinge line narrowly incised. Greatest length median; greatest height slightly posterome- dian ; greatest width posteromedian. Left valve with crescentic groove subparallel to posterior margin, extending from posterodorsal third of valve to pos- teroventral quarter. Right valve with similar, shorter groove in posterior third which does not extend as far dorsally as groove in left valve. Shell surface otherwise smooth. Muscle sear apparently oval, situ- ated on low ridge or swelling which is not seen on exterior of valve. Hinge short, straight; details of hingement not known. Contact groove present around free margins of left valve, apparently inter- rupted ventrally. Material.-Eight carapaces and five single valves from the McCann Hill Chert. Measurements.-The holotype is 0.75 mm long, 0.45 mm high, and 0.40 mm wide. Types.-Holotype, USNM 178835; USNM 170336, 173836, 173837, 173838. Discussion.-This species was originally assigned to Healdia because of the crescentic posterior groove; however, it lacks the characteristic posterodorsal flattening of true Healdia. Further study of the mus- cle sear and the character of the groove suggests that Neocraterellina? crescentifera is a thlipsurid. Kran- dijevsky (1968, p. 72) proposed the genus Neocra- terellina, with Craterellina oblonga Ulrich and Bass- ler, 1913, as the type species, for thlipsurids with one curved or horseshoe-shaped or round closed fur- row. Thlipsurella orthoclefta Swartz, 1982, was in- cluded in this genus by Krandijevsky (1968, p. 72). This species is comparable to N.? crescentifera in having a single posterior groove, but the groove of N. orthoclefta is straight rather than crescentic as in N.? crescentifera. The holotype of N. orthoclefta (USNM 86504) from the Shriver Chert in Pennsyl- vania appears to have a more strongly curved dor- sum than illustrated by Swartz (1932, pl. 11, fig. 3a) and thus is closer to N.? crescentifera than is shown by the figures of both species. Occurrence.-USGS collections 6492-SD, 7082- SD, 7033-SD, and 7037-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alaska. Family indet. Genus MICROCHEILINELLA Geis, 1933 Microcheilinella? sp. Plate 14, figures 3, 4 Description.-Carapace small, tumid, subovate in paratypes, 40 OSTRACODES FROM LOWER DEVONIAN FORMATIONS IN ALASKA AND YUKON TERRITORY lateral view. Left valve overlapping right all around except dorsally. Hinge half greatest length, occupy- ing middorsal area, incised between shoulders of both valves. Greatest height and length median; greatest width in posterior third. Surface smooth. Material.-Two specimens from the Prongs Creek Formation. Measurements.-The figured specimens are 0.60 mm long, 0.34 mm high, and 0.35 mm wide. Types.-Figured specimens, GSC 29514, 29515. Discussion.-This species is not readily distin- guishable from numerous other small ovate smooth ostracodes of microcheilinellid type. The hinge of this species may be more incised than that of many other species, but this could be a matter of preser- vation. Until a complete revision of this genus is attempted, it is felt that a specific designation is unnecessary. Occurrence.-Ludvigsen collection V-3 from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. Ostracode indet. 1 Plate 14, figure 20 Description.-Hinge line straight; prominent me- dian suleus in anterior half of valve; sulcus extends nearly to midvalve. Presulcal node ovate, indistinct; slight indication of S1 in anterodorsal corner of valve. Lateral outline subovate. Surface slightly papillose with faint posterior lineation. Anteroven- tral flange or spur projecting from right valve mar- gin in position of spur on Hanaites. Pronounced tubercle present in posterodorsal quarter of valve. No other marginal structure observed. Material.-Two incomplete specimens from the Michelle Formation. Measurements.-The incomplete figured specimen is 0.90 mm long and 0.55 mm high. Types.-Figured specimen, GSC 29511. Discussion.-The specimens are crushed and too poorly preserved for more exact identification. Su- perficially they appear to have some characteristics of Hanaites but apparently are not reticulate. Occurrence.-Ludvigsen collection I-3 from the Michelle Formation, Hart River, Yukon Territory. Ostracode indet. 2 Plate 14, figure 22 Description.-Lateral outline semielliptical, am- plete to postplete. Hinge line straight ; anterior mar- gin smoothly rounded ; ventral margin gently curved, swinging up into more acutely curved posterior mar- gin. S1 shallow and poorly defined; S2 wide, some- what deeper than S1, extending about half height of valve; weak S3 or hemisuleus in posterior quarter of valve. L1 broad, smoothly arched; L2 small, ovate, set below hinge line ; L8 broad, slightly humped above hinge line; L4 smooth, sloping to posterior margin. Anterior end of valve with poorly defined velar bend which extends posteriorly to beneath L3 but merges with surface anterior to small posteroventral spine. Small anterodorsal spine above S2. Shell surface apparently smooth to very finely granulose. Material.-One left valve from the McCann Hill Chert. Measurements.-The figured specimen is 1.30 mm long and 0.75 mm high. Types.-Figured specimen, USNM 173839. Discussion.-The anterior position of the weak velar bend, the small posteroventral spine and the humping of L3 above the hinge line suggest that this specimen may be an aberrant hollinid, but the weak sulcation and poorly developed velar structures are atypical of the Hollinacea. Occurrence.-USGS collection 6492-SD from the McCann Hill Chert, Eagle (D-1) quadrangle, Alas- ka. Ostracode indet. 3 Plate 14, figures 15, 16 Description.-Carapace small, tumid, subovate- triangular in lateral view. Right valve overlapping left all around except dorsally. Hinge half greatest length, occupying middorsal area, incised between shoulders of both valves. Valves with narrow an- terior and posteroventrally drawn-out flanges; more pronounced on right valve. Greatest height and width median; greatest length in ventral half. Sur- face somewhat granular, possibly with internal tubules. Material.-Two specimens from the Prongs Creek Formation. Measurements.-The figured specimens are 0.60 mm long, 0.35 mm high, and 0.40 mm wide. Types.-Figured specimens, GSC 29516, GSC 29517. Discussion.-If these specimens are interpreted correctly, they possess right-over-left overlap. A re- versal of overlap may exist with some pachydomellid genus, but this cannot be substantiated with the ma- terial at hand. These specimens are similar to the specimens from the McCann Hill Chert previously described as "pachydomellid, indet. 1" but differ in having the greatest thickness median rather than posterior and in having both anterior and posterior flanges. Occurrence.-Ludvigsen collection V-3 from the Prongs Creek Formation, Solo Creek, Yukon Terri- tory. 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Abbreviations Abditoloculina BIROAAEG | cour sense 16, 17 clausa __ " eae ee Abortivelum truncatum _ __ 19, pl. 6 Acanthoscapha - __ ~... #1, 82 ..- 82 §DP 6, $1, pl. 11 Acknowledgments ________________-_--- 1 acuminatum, Infractivelum _ ___ 6, 21, 22, pl. 8 Adelphobolbing 7, 19, 21 aliquanta | _____._- __ 6, 19, pl 6 BMDO8® 20 6, 20, pl. 7 MEDIA enne une um 20 20 PDaDIHOSR .. .._. once nen nees eunos es 20 ece ne cence e 20 pronpsendie ...._.._____...... 6, 20. pl. 7 spicata ______ trilobata _- Ages of formations ___________________ 4 ._____._________cccuullll 14 PHHEAIC 12-2 isu 6, 14, 15, pl. 5 modilineghea | __..___........ 6, 14, 15, pl. 5 unilineata ___ -- 6, 14, 15, pl. 5 SD | -- 6, 15, pl. 5 alatus, Pseudocyproides _______________ 33 aliquanta, Adelphobolbina ________ 6, 19, pl. 6 AUAKENG : ons as 32 AltaiSayan region, Siberia, U.S.S.R. __ 36 antespinosa, Hollinella ________________ 18, 19 APOTCRIES! LLL scene eus 27, 28 auriculiferus _ __ -- 6, 7, 28, pl. 10 Chuchlengie 29 crossotus ___ Pe 27 whiteavesi _ hes 29 ) L coll lose ener ee 27 ApatobolbfM@ | 14 arctigena, Beyrichia (Beyrichia) ______ 10 ATCYZOAIGAQ 22 argutula, Knozites . as 15 OGHUNEEE ! _ LLC- nc ee cies 16 auriculiferus, Aparchites ______ 6, 7, 28, pl. 10 B BMPAI : am 80, 31, 32 dejecta _.. - 6, 80, pl. 11 CMOCIOG | 80 leguminoides = _____________ 6, $0, 31, pl. 11 30 (_L colo oe in nanan 31 tramsversocostata __________________ 31 Bairdiidae ________-- «~. #0, 82 Bairdiocyprididae . a $5 $5 cordiformis | Lic__.._.l..... 6, 7, 85, pl. 12 §D ) 6, 85, pl. 12 INDEX [Italic page numbers indicate major reference] Page Bairdichealdites 86 rozhdestvenskayae _________________ 36 scapulatus | ________ - 6, 86, pl. 12 Bairdi@MIG8 . 81 solhmg ._.... --- 6, #1, pL 11 barathrota, Trypetera _________________ 37 Barychithis 86 OPIITROTRYSG 37 SD | 6, 86, pl. 19 parychilinidae 86 Bashkiria, U.S.S.R. - 7, 28, 29, 35 32, 88 COMNOEE: . oc iene ce due be nace nw 33 SD 6, 83, pl. 11 Beecherellidae | $1, 32 Bell Sh&lg 17, 27 BeéFOUNBIG | Berounellidae Beyrichia | _______ (Beyrichia) - ____________ y APOHMQERE 10 brabb? ! 6, 10, pl. 2 §P. A 10 §D. B 10 (Seabribeyrichia) __________________ T, 10 churkini = _____ - 6, 10, pl. 8 foliosa ___. R 11 $p s 11 (Beyrichia) arctigena, Beyrichia _____ 10 brabbi, Beyrichia _____________ 6, 10, pl. 2 #p. A, Beyrichts L.___..___l_.lcll 10 sp. B, Bsyrichte 10 Beyrichiidae _________- 108, 9 Beyrichiinae __. - 10 Bibliography _ a 41 L200 00000000 ceric eries nesses is $4 $D | 6, 84, pl. 12 bicornis, Ogilvites ________________ 6, 15, pl. 6 bilineata, Alaskabolbina ________ 6, 14, 15, pl. 5 binoda, Condracypris __________________ 36 binodata, Abolitoloculina ______________ 16, 17 Biya beds, Bashkiria, U.S.S.R. _______ 28, 35 Blackstone River _____________ -- 112,8, 5,8 blackstonensis, Kuresaaria ___ 6, $5, pl. 12 Blue Fiord Formation ______________ 5, 8, 30 Bohemia ) 5 borealis, Treposella ________________ 6, 9, pl. 1 brabbi, Beyrichia (Beyrichia) _____ 6, 10, pl. 2 brevis, Hamites ____________ 6, 24, 25, 26, pl. 9 bulbosa, Adelphobolbina ______________ 20 Bythocypris ap 35 C Camden Cherk 7 camdenensis, Camdenidea _____________ 33 Camdenidea camdenesis $D. bek Canadian Arctic Archipelago _________ carinata, Beecherella _________________ 33 caurina, Tricornina a=«- 6, #8, pl 12 | Ls enue seule nen 87 (Invisibila) ag 87 38 SP event 7, 87, pl. 14 Page CHIECROUIIEE .u .c cer 32 L2 22 limitaris | _____ . 5, 28, pl. 8 | 22, 28 6, 22, 23, pl. 8 $D earners seem 22 chuchlensis, Aparchites ______________. 29 churkini, Beyrichia (Scabribeyrichia) _ ___. 6, 10, pl. 3 circulata, Libumella _____________ 6. 28, pl. 10 clausa, Abditoloculina . --- 6, 16, $1.6 . . .. Soll aan ses 9 compressa, Hollina a 17 COMATGOCYBMIG 36 DIROGE ede de ces we we 36 Contact, McCann Hill Chert-Road River Formation _________- 2 Michelle and Road River Formations 2 Nation River Formation-McCann Hill Cherf: ____._._....l. 3 Ogilvie and Michelle Formations.. 8 Prongs Creek and Road River Formations _..____._.___, 3 cordiformis, Bairdiocypris ________ 6, $5, pl. 12 Correlation . L222 0000 00020020 I 4 intercontinental __ aas T Craspedobolbininae . _. 1 9 Craterellina oblonga .______ a+ 89 crescentifera, Neocraterellina 7, 89, pl. 14 crossotus, Aparchibes ._._.___._..___.. 27 SubsrolithTbe® 27 Ctenoloculinidae |.....__..._......._._.. 16 Ctencloculintnae |..___..___.__L_....... 16 Cypridinidae 32 | 14 D dalhousiensis, Eukloedenella ___________ 29 dejecta, Bairdia ____._______ 6, 80, pl. 11 Devon Island, Canada _________________ 5 discoides, Libumella ___________ 8, T. 27. pl. 10 E Eagle (D-1) quadrangle, Alaska ______ 3, 8 eifeliensis, Obotritia __________________ Ellesmere Island Etlestheri@ OUMEL . Sue ean a 6+ ok ar an km mie an a iil s eel emaciata, Bairdia RODEYMERIA | 22 zon venules aman se eam 11 BFI | 8p L..... . w- Jez one case ns nine dalhousiensis Pécia soloensis | __ sulcifrons _. HMONICHNE Lu an SD ss cre anes bk Eurekaspirifer pinyonensis Zone ______ 5 Eurychilina mirabilis __________________ 24, 25 45 46 Page F Falls of the Ohio River ______________ I FORTIDONEE | .n as nee T, 37 maltiepinasus ________________. 6, 17, pl. 7 Falsipolicinae 17 TIGCCIUONON | ei eck 7, 9, 21 informis ___ L 21 teleutaca - __ ser 21 SD | 6, 21, pl. 8 foliosa, Beyrichia (Scabribeyrichia) ___ 11 Fossil collections _____..._._________ _._. 8, 5, 8 (Framella), Polomiella ________________ 80 scheii, Poloniella __________ 6, 8, 80, pl. 11 G J.. b 9 Gasterocoma bicaula _____________:____ 5 Genshaw Formation ._____________-_.. 17, 20 givetiana, Halliella (Hamaites) ________ 24 :! - L- seus med 25 gotlandica, Kuresaaria _ 35 gramosa, Parabolbina __ 17 GPOUW | 27 Guerichina strangulata Zone ________. 5 H 0000 08 th ue at us anal aes 24 (Hamaites) givetiama _____________ 24 _.. cae 24, 40 ! Luu eee ceases 6, 24, 25, 26, pl. 9 givetiana linearis platus = __ spinosus $p. A& ... $D..B J. (Hanaites) givetiana, Halliella _______ 24 fart River 1,2, 8, 8 hartley, Mesomphalug .__.____.._____.. 9 Harz region, Germany . M 5 He@ldi® 2.2. t 39 sp M 39 Heteromorph, defined _________________ 18 Millard PeAK 1, 8 HOHSNE .L 2.22 n cns ess bue aind 7, 17 - Hei ue nes 17 insolens _. pyzidata 8p ...... zc 7, 18, 21 . = anu 18, 19 Tudvids@nt. wo eis n nie snus s 6, 18, pl. 7 paucitubsreulata ..._....._...... 6, 18, pl. 7 DIHEL (Praeholinella) __ 102. SBG un an sel SERMHEDSU :! L u- srs bass se SD.) ~. eer ieaisernsstonseres casks on 18, 22 Hollinellidae Hollinidae - Holli Ma® | c- hypercala, Parabolbing ...... I informis, Flaccivelum _________________ 21 TnfrOCHORNN _. _ . _.. -. . oo oen i's comum mis m ose 21 acuminatum __ - 6, 21, 88, pl. 8 6, 21, 22, pl. 8 insericus, Neoaparchites __________ 6, 28, pl. 10 . ncn an 28 17 INDEX Page insolita, Abditoloculina _____________._ 16 inventa, Voronina _____________ 6, 7, 87, pl. 13 (Invisibila), Cavellina _______________ 87 porrecta, Cavellina ________________ 38 §p., 7, 87, pl. 14 J Jeffersonville, Ind. .....-......----««-- T Jeffersonville Limestone ____________-- 7, 20 TOTUOMEES! ' arr bank 18, 21 K Kalkberg Limestone ______________---- 32 RWEDYCHG _... susie #4 (Kirkbyellay | 24 §D / - 6, 24, pl. 9 (Kirkbyella), Kirkbyella ______________ 24 $p., 'Kirkbyslln 6, 24, pl. 9 Kirkbyellidae | 24 | 29 Kmosites argutule L..l.ulcclllllc.llL 15 Konmeprusia subterarmata ______________ 5 SD" een eel rental nce enbaws 5 Krekov beds, Salair district, Siberia, U.S.S.R. 36 Kuresaaris ._.____.. 85 blackstonensts 6, 85, pl. 12 | ._.. uur novus eee bowes 35 L leguminoides, Bairdia ________ 6, 80, 31, pl. 11 -..... dus cares 14 .. 2200 ALU c e #7 circulate _ discoides _. -- 6, 28, pl. 10 -- 6,4. 27, pl. 10 SD ASL beerarsen 27 limitaris, Chironiptrum ___________ 6, 22, pl. 8 linearis, - Hamaites | ________ 6, 24, 25, 26, pl. 9 Localitigs "TL. 8 Logisyille, (Ky T ludvigseni, Holinella C.. 36, 18, pl. 7 Iyont, . Tréeposella 6, 9, 10, pl. 1 M McCann Hill Chert ...._...-._.._._....L 2 collection localites . ts 8 feung -...... - =+ 4 .- -e ats 3 medialis, Adelphobolbina __________ 6, 20, pl. 7 megalia, Adelphobolbina ______________ 20 MesompDRGIUS 4, 9 ROTNHEYI | .o 9 SD - 6, 9, pL. 1 Michelle Formation ___ Hs 2 collection localites . a+ 8 fAUNA L-- ues 5 ~...... stela cen 3 Microcheiinelia | 89 $P Les n ELDER ecus T. 89, pl. 14 Migration routes 1 minuta, Berounella ___ «.- 6, 64. pl. 18 mirabilis, EBuryohiltna 24, 25 Monograptus yulkonensis __________ «s B, $ mucrongta, 30 multispinosus, Falsipolles ________ 6, 17, pl. 7 N Nation River Formation ______________ 3 mavicula, Acanmthoscapha ______________ 32 BMPOLG - . .-. .-- oom 31 NEOABPATCMICE 28 Page . 6, 7, 28, pl. 10 obsoletus __ 28 Neocraterellina 89 - 7, 89, pl. 14 7, 81, 38 . pertumidus profusus | __ $p .. Nodella ___. Nodellidae | nodilineata, Alaskabolbina ___. 6, 14, 15, pl. 5 notabilis, Newsomites __________________ 38 Novgorod district, U.S.S.R. _________-- 16 Nowakia barrandei 4 parabarrandei 5 0 oblonga, Craterelling 39 ObGtribi@ A 28 eifeliensis __ aos PH SD -- 6, 28, pl. 8 obsoletus, Neoaparchites ______________ 28 | aan mis 28 Ogilvie Formation 8, 5 ...... ...- 15 ... ...o anwar 16 DiCOPWiG 6, 15, pl. 6 viostathmicum, Chironiptrum --.~. 28, 28 opisthorhysa, Barychilina ________ as 37 orthoclefta, Thlipsurella ________ a= 39 Ostracode collections _________________ 5, 8 Ostracode indet. 1 __.._.____._ ___ 7, 40, pl. 14 indet, . 2) 7, 40, pl. 14 indet.: 8. 7, 40, pl. 14 Ostthuringer, Germany _______________ g ovata, Ellesmeria ________ ness 37 Pachydomellid indet. 1 -- 7, 88, pl. 14 indet. 2 - Ts 88, pl. 14 Pachydomellidae 88 papillata, Adelphobolbina _____________ 20 papillosa, Adelphobolbina _____________ 20 Pavabolbing | 1,4? | neenee ee dat 17 . ie catenins 17 pulchella __ trem 17 §$DP -- 8, 17, pL B Parabolbininae ________ Pesi 2? Paraparchitidae 28 Paraspirifer acuminatus Zone _________ T paucituberculata, Hollinella ______ 6, 18, pl. 7 pertumidus, Newsomites _______________ 31, 38 Philyctiseaphe ...._....... 27 pinguis, Adelphobolbina _ 20 platum, Proplectrum | ____ 24 plates, Mumiffés 25, 26 plaute, Hollinell®) 18 Plum Brook Formation 39 POIOHIGHE | «oon 80 (PPAM@UN) \. 80 schett .- 6, 8, #0, pl. 11 Polygnathus dehiscens ________________ 5 -- ele en 5 I€H81 | Lucu 5 Porcupine. River 4 porrecta, Cavellina (Invisibila) ______ 38 (Pracholinella), Hollinella ___________ 18, 21 praepilata praepilata, Praepilatina _____ 36 sibirica, Praeplatina ______ 8, 8, #6, pl. 18 Praepilatina 86 praepilata praepilate _____________. 36 praepilata sibirica _________ 6, 8, 36, pl. 13 PrimibM@ 28 Page profusus, N ewsomites ____-.------------ 31, 38 Prongs Creek Formation -__----------- 2 collection localities 8 lithology - ------------------ 3 prongsensis, Adelphobolbina ____--- 6, 20, pl. 7 Proplectrum | platumy 24 Pseudocyproides .__----- BH - 33 pulchella, Parabolbina .__._.-._---------- 17 pumila, Hollinell@® _____---__---------- 18 Punctaparchites _______-_-_--------- 2% 28 imsericus | ________-_----------- ss 28 \ ...._.-- =s 28 pyzidata, Holling 17 Q Quasillitidae ______-------------------- 89 R recta, Eukloedenella .___._.------- 6, 29, pl 11 Rectobairdia | _____________------------- 81 " - 6, $1, pl. 11 Regional relationships _--_------------ 3 reticularis, Chironiptrum ______ 6, 22, 23, pl. 8 Rheinische Schiefergebirge, Germany... 7 Richardson Mountains ___-__---------- 1 Road River Formation ______--------- 2 robusta, Eriell@ 39 rozhdestvenskayae, Bairdichealdites ___ 36 rugosa, Punctaparchites ______.__._----- 28 Ruptivelum | 21 S Saccarchites 8p __________------------- 27 Salair district, Siberia -- as 8 Salmontrout Limestone --- +- 4 Salmontrout River --_------- a= 4 (Scarbribeyrichia), Beyrichia _______-- 7, 10 churkini, Beyrichia _______---- 6, 10, pl. 3 foliosa, Beyrichia ________.__------- 11 sp., Beyrichia 11 SC@Dhima | 32 scapulatus, Bairdiohealdites ___--- 6, 36, pl. 13 scheii, Poloniella (Framella) -- 6, 8, 80, pl. 11 Schoharie Formation --__------------- x Schohariellq = _________----------------- 14 Sedimentation - ____---------------~~--- 2 sella, Hollimell® ______-__-----------~-- 19 senticosa, Hollinella _--_--- peas 18 serratulus, Subartichites __. .. 6, 87, ph. 9 Shidelerites | _________------------------ 7, 82 EYDUS ......«««- L... $2,098, pL 11 yulonensis | _________--------- 6, $2, pl: 11 Shriver Chert __--- 39 sibirica, Praepilatina praepilata. 6, 8, 36, pl. 13 sohni, Bairdiolites ____._._--------- 6, $1, pl. 11 Solo Creek 1.3.5 solo, Yukonibeyrichia _... 6, 11, 18, pl. 4 soloensis, Eukloedenella __. v. 6, #9, pL. 11 spicata, Adelphobolbina ____.___-------- 20 spiculosum, Infractivelum ___.. 6, 21, #8, pl. 8 spimnosus, - Hamaites = ___-------- 6, 24, 25, pl. 9 Stratigraphy | 2 stellata, Treposella ______-.------------ 9 Subarctichites ______-.------ s 27 crossotus | ______------- wo 27 serratulus 6, 27, pl. 9 sulcifrons, Eukloedenella ____.___------- 29 'C. Teenomorph, defined ------------------ 18 Teicherticeras lemgi _______-_---------- 5 teleutaea, Flaccivelum _________------- pal TerminolOgy \ -----------------------==~ 8 Tetracornella _ _____---------- 2s 24 Thlipsurella orthoclefta __.. s 39 Thlipsuridae ---------- Ss 89 Trail River 3 tramsversocostata, Bairdia . 31 Treposella - borealis O4 | 6, 9, 10, pl. 1 stellata 9 BD | 9 Page Treposellinge | _-_-_-------------------- 9 TMCOPRMMQ | 38, 34 COUPOLE 6, #8, pl 11 §D | 6, 84, pl. 12 Tricorninidae | 38 trilobata, Adelphobolbina ______-.-_----- 20 truncatum, Abortivelum __ _ 6, 19, pl. 6 | 37 barathrotu ____________ccocc_------- 37 " o n t 6, 87, pl. 14 Tubulibairdia | ____________---_--------- $8, 39 8D \ 7, 88, pl. 14 Turkestamella acuaria ___________------- 5 typus, Shidelerites _________.---- 82, 33, pl 11 U umbilicata, Eukloedemella _______.__-.--- 29 unilineata, Alaskabolbina ____-- 6, 14, 15, pl. 5 Ural Mountains L____________------- 7, 28, 290 V voronensis, Voromina __________-_----- 37 o s oo 87 | 6,7, 87, pl. 13 voronengig _______._________.«._«___- 37 W 32 29 21 C Yukon Shelf _____________-_---------- 1 yukonensis, Monograptus ______--_----- 8 Shidelerites | .__.._.__._..____.-.- 6, #8, pl 11 Yukonibeyrichia _ __ - 6, 11, 12, 13, pl. 4 Yukonibeyrichia | 11 8010 6, 11, 18, pl. 4 yukonensis _____-- ... 8, 11, 18, 18, pl 4 PLATES 1-14 PLATE 1 [All figures X 30] FIGURES 1,2. Mesomphalus? sp. (p. 9). Broken tecnomorphic right and left valves from the Prongs Creek Formation, Ludvigsen collection V-3. Figured specimens, GSC 29439, 29438. 8, 4. Treposella sp. cf. T. lyoni (Ulrich, 1891) (p. 9). Immature teenomorphic right and left valves from the McCann Hill Chert, USGS collection 7037-SD. Figured specimens, USNM 173728, 173729. 5-10. Treposella borealis n. sp. (p. 9). 5. 6. 7. H 10. Small teenomorphic left valve from the McCann Hill Chert, USGS collection 6492-SD. Paratype, USNM 170351. Tecnomorphic right valve from the Prongs Creek Formation, Ludvigsen collection V-3. Paratype, GSC 29453. Ventral view of holotype, USNM 170352, showing the treposelline bridges across the ventral sur- face of the crumina. McCann Hill Chert, USGS collection 6492-SD. Lateral view of heteromorphic right valve, holotype, USNM 170352. Interior view of a heteromorphic left valve from the McCann Hill Chert, USGS collection 7032-SD, showing the strut across the crumina. Paratype, USNM 173731. Large tecnomorphic right valve from the McCann Hill Chert, USGS collection 6492-SD. Paratype, USNM 173730. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 1 ls e M MESOMPHALUS? AND TREPOSELLA PLATE 2 FiGurES 1-8. Beyrichia (Beyrichia) brabbi n. sp., X 30 (p. 10). | 1. 2. 8. Small teenomorphic left valve, paratype, GSC 29474, from the Prongs Creek Formation, Ludvigsen collection V-3. Small teenomorphic right valve, paratype, USNM 173732, from the McCann Hill Chert, USGS col- lection 6492-SD. Tecnomorphic left valve, paratype, USNM 173733, from the McCann Hill Chert, USGS collection 6492-SD. Tecnomorphic left valve, paratype, GSC 29473, from the Prongs Creek Formation, Ludvigsen collec- tion V-8. Ventral view of heteromorphic right valve, paratype, USNM 173734, from the McCann Hill Chert, USGS collection 6492-SD. Large tecnomorphic right valve, paratype, USNM 170347, from the McCann Hill Chert, USGS col- lection 6492-SD. Heteromorphic right valve, holotype, USNM 170346, from the McCann Hill Chert, USGS collection 6492-SD. a Heteromorphic left valve, paratype, USNM 173736, from the McCann Hill Chert, USGS collection 6492-SD. ~ m E < 1 Da un lsd co m m & < m. ~1 < Z f m ~ m l O m A GEOLOGICAL SURVEY BEYRICHIA (BEYRICHIA) PLATE 3 FicurEs 1-9. Beyrichie (Scabribeyrichia) churkini n. sp., X80 (p. 10). 1. Small teenomorphic right valve, paratype, USNM 173737, from the McCann Hill Chert, USGS col- lection 6492-SD. 2. Small tecnomorphic left valve, paratype, USNM 173738, from the McCann Hill Chert, USGS col- lection 6492-SD, showing four spines fusing to form calcarine spine. 3,4. Tecnomorphic right valves, paratypes, GSC 29472, 29471, from the Prongs Creek Formation, Lud- vigsen collection V-3. 5. Large tecnomorphic left valve, paratype, USNM 170348, from the McCann Hill Chert, USGS col- lection 6492-SD, showing unusually well developed fissus. 6,7. Ventral and lateral views of heteromorphic right valve, holotype, USNM 170349, from the McCann Hill Chert, USGS collection 6492-SD. 8. Tecnomorphic left valve, paratype, GSC 29470, from the Prongs Creek Formation, Ludvigsen collec- tion V-5. 9. Heteromorphic left valve, paratype, GSC 29469, from the Prongs Creek Formation, Ludvigsen col- lection V-3 . § FINN.“ * ne 22 24 yeoth 4) ifimbffi ”fiflflrwhv‘a. , Ll wV‘PQ’f- 11..¢firv p“. ‘fl h. k tae ao a - ® PROFESSIONAL PAPER 825 PLATE 3 & * a. Vat» 4 S & & Dn ig s c f U el ~ R fas C R & p a o GEOLOGICAL SURVEY PLATE 4 [All figures X 30] FIGURES 1-4. Yukonibeyrichia solo n. sp. (p. 13). 1. 2. 3, 4. Tecnomorphic left valve, paratype, GSC 29436, from the Prongs Creek Formation, Ludvigsen collection V-8. Tecnomorphic right valve, holotype, GSC 29435, from the Prongs Creek Formation, Ludvigsen collection V-3. Heteromorphic left valve, lateral and ventral views, paratype, GSC 29437, from the Prongs Creek Formation, Ludvigsen collection V-4. 5-11. Yukonibeyrichia yukonensis n. gen., n. sp. (p. 12). 5, 6. 7. 8. 9. 10. 11. Broken heteromorphic right valve, lateral and ventral views, paratype, USNM 173740, from the McCann Hill Chert, USGS collection 7032-SD. Small teenomorphic right valve, paratype, GSC 29434, from the Prongs Creek Formation, Lud- vigsen collection V-3. Small tecnomorphic right valve, paratype, USNM 173741, from the McCann Hill Chert, USGS collection 7032-SD. Small teenomorphic left valve, paratype, USNM 170345, from the McCann Hill Chert, USGS col- lection 6492-SD. Tecnomorphic left valve, holotype, GSC 29432, from the Prongs Creek Formation, Ludvigsen col- lection V-3. Heteromorphic left valve, paratype, GSC 29433, from the Prongs Creek Formation, Ludvigsen collection V-3. < m E < PS Au Lo ~ so m ® AL < f 3 < Z C w w +] en O m ©. YUKONIBEYRICHIA Y" 4 gaze; M ,-,fl3!t GEOLOGICAL SURVEY FIGURES - 1-6. 7-10. 11,12. 13-15. 16-21. PLATE 5 [All figures X 30] Alaskabolbina nodilineata n. sp., from the Prongs Creek Formation, Ludvigsen collection V-3 (p.14). 1. Lateral view of heteromorphic? right valve, holotype, GSC 29512. 2. Interior of holotype showing possible cruminal structure. 3. Ventral view of holotype showing double row of subvelar tubercles. 4-6. Lateral, interior, and dorsal views of heteromorphic? left valve, paratype, GSC 29513. Alaskabolbina? sp., from the McCann Hill Chert, USGS collection 7037-SD (p. 15). 7. Small right valve, figured specimen, USNM 173840. 8. Small left valve, figured specimen USNM 173841. 9. Larger broken right valve, figured specimen, USNM 173842, showing more extended velum. 10. Small papillose right valve, figured specimen, USNM 173843, lacking dorsal cusps. Alaskabolbina sp. (p. 15). 11. Small immature right valve, figured specimen, USNM 173844, from the McCann Hill Chert, USGS collection 7037-SD, showing dorsal cusps. 12. Immature left valve, figured specimen, USNM 173845, from the McCann Hill Chert, USGS col- lection 7037-SD. Possibly juvenile form of Alaskabolbina nodilineata, n. sp. Alaskabolbina unilineata n. gen., n. sp. (p. 14). 13. Right valve, holotype, USNM 173745, from the McCann Hill Chert, USGS collection 6492-SD. 14. Ventral view of holotype showing single toric ridge. 15. Dorsal view of holotype. Alaskabolbina bilineata n. sp., from the Michelle Formation, Ludvigsen collection II-11 (p. 14). 16. Broken left valve, paratype, GSC 29465, showing dorsal tubercles. 17. Broken left valve, paratype, GSC 29467. 18. Broken right valve, paratype, GSC 29468. 19. Broken right valve, paratype, GSC 29466. 20. Left valve, holotype, GSC 29464. 21. Ventral view of holotype showing double toric ridges. PROFESSIONAL PAPER 825 PLATE 5 GEOLOGICAL SURVEY 9. x s q ~ O o x ha um %t ] ° an Z, < ~ S fo ] ad o % hd t t 1 Ss FIGURE 1. 10-16. 17-22. 28. PLATE 6 [All figures X 80] Ogilvites bicornis n. sp. (p. 15). Left(?) lateral view of holotype, GSC 29454, from the Prongs Creek Formation, Ludvigsen collection V-3. Abditoloculina clausa n. sp., from the McCann Hill Chert (p. 16). 2-4. Left-lateral, right-lateral, and ventral views of the holotype, USNM 170338, a heteromorphic carapace, USGS collection 6492-SD. Figure 4 shows the closed loculi characteristic of the species. 5,6. Ventral and left-lateral views of a tecnomorphic carapace, paratype, USNM 173746, USGS col- lection 6492-SD. 7,8. Exterior and interior views of a heteromorphic left valve, paratype, USNM 173747, showing loculi, USGS collection 7033-SD. Abditoloculina clausa? (p. 16). Lateral view of an immature tecnomorphic right valve from the McCann Hill Chert, USGS collection 7033-SD. Figured specimen, USNM 173750. Abortivelum truncatum n. gen., n. sp., from the McCann Hill Chert, USGS collection 7032-SD (p. 19). 10,11. Right-lateral and ventral views of a heteromorphic carapace, paratype, USNM 173751. 12-14. Right-lateral, ventral, and dorsal views of a teenomorphic carapace, paratype, USNM 173753. 15,16. Exterior and interior views of a heteromorphic left valve, the holotype, USNM 173752. Adelphobolbina aliquanta n. sp. (p. 19). 17. Immature tecnomorphic right val right valve, paratype, USNM 170341, from the McCann Hill USGS collection 6492-SD. 18. Lateral view of a tecnomorphic right valve, paratype, USNM 170341, from the McCann Hill Chert, USGS collection 6492-SD. This specimen was originally thought to be a heteromorph. 19. Tecnomorphic left valve, paratype, USNM 173756, from the McCann Hill Chert, USGS collec- tion 6492-SD, showing anterodorsal cusp. 20,21. Exterior and interior views of a heteromorphic right valve, the holotype, USNM 173755, from the McCann Hill Chert, USGS collection 6492-SD, showing the character of the velum. 22. Tecnomorphic left valve from the Michelle Formation, Ludvigsen collection II-13, paratype, GSC 29497. Hollina sp. (p. 17). Tecnomorphic right valve, figured specimen, GSC 29441, from the Prongs Creek Formation, Ludvigsen collection V-3. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 6 OGILVITES, ABDITOLOCULINA, ABORTIVELUM, ADELPHOBOLBINA, AND HOLLINA FIGURES - 1-3. 4, 5. 6-8. 9-18. 14-16. PLATE 7 [All figures X 30] Hollinella ludvigseni n. sp. (p. 18). 1. Tecnomorphic right valve, paratype, USNM 173764, from the McCann Hill Chert, USGS collec- tion 6492-SD. 2. Tecnomorphic right valve, holotype, GSC 29462, from the Prongs Creek Formation, Ludvigsen col- lection V-8. 3. Heteromorphic right valve, paratype, GSC 29463, from the Prongs Creek Formation, Ludvigsen collection V-8. Adelphobolbina sp. ef. A. medialis Stover, 1956 (p. 20). Technomorphic left and right valse, figured spe- cimens, USNM 173759, 173760, from the McCann Hill Chert, USGS collection 6492-SD. Hollinella paucituberculate n. sp., from the Michelle Formation, Ludvigsen collection II-13 (p. 18). 6. Heteromorphic right valve, paratype, GSC 29495. 7. Tecnomorphic left valve, paratype, GSC 29496. 8. - Heteromorphic left valve, holotype, GSC 29494. Adelphobolbina prongsensis n. sp., from the Prongs Creek Formation (p. 20). 9. Tecnomorphic left valve, paratype, GSC 29501, Ludvigsen collection V-3. 10. Tecnomorphic left valve, paratype, GSC 29502, Ludvigsen collection V-4, showing papillose pos- terior. 11. Heteromorphic right valve, holotype, GSC 29498, Ludvigsen collection V-3. 12. Heteromorphic left valve, paratype, GSC 29500, Ludvigsen collection V-3. 13. Heteromorphic left valve, paratype, GSC 29499, Ludvigsen collection V-3. Falsipollex? multispinosus n. sp. (p. 17). 14. Broken tecnomorphic left valve, paratype, USNM 173762, from the McCann Hill Chert, USGS collection 6492-SD. 15.. Heteromorphic right valve, holotype, USNM 173761, from the McCann Hill Chert, USGS collec- tion 7032-SD. 16. Interior of holotype showing dolonal pouch. PROFESSIONAL PAPER 825 PLATE 7 GEOLOGICAL SURVEY a be esl ~] ~] © c ”M R, a Z, < 3 m fq al O pal S H by A bis < ~ ] b 2 ~] 1 S jas! FIGURE 2-8. 9-14. 15, 16. 17, 18, 19-28. 24-27. PLATE 8 [All figures X 30 except as noted] Obotritia? sp. (p. 23). Left valve, figured specimen, USNM 1737 74, from the McCann Hill Chert, USGS collection, 7037-SD. Chironiptrum limitaris n. sp., (p. 22). 2. Left-lateral view of carapace, paratype, USNM 173769, from the McCann Hill Chert, USGS col- lection 6492-SD. 3,4. Right-lateral and left-lateral views of carapace, paratype, USNM 170337, from the McCann Hill Chert, USGS collection 6492-SD. 5. Right valve, paratype, GSC 29455, from the Prongs Creek Formation, Ludvigsen collection V-3. 6,7. Left-lateral and dorsal views of carapace, holotype, USNM 173770, from the McCann Hill Chert, USGS collection 7033-SD. 8. Right valve, paratype, USNM 173771, from the McCann Hill Chert, USGS collection 6492-SD. Chironiptrum reticularis n. sp., from the Michelle Formation (p. 22). 9. Left valve, paratype, GSC 29459, Ludvigsen collection II-13. 10. Dorsal view of carapace, paratype, GSC 29461, Ludvigsen collection II-10. 11. Ventral view of carapace, paratype, GSC 29460, Ludvigsen collection II-10. 12. Left-lateral view of carapace, paratype, GSC 29458, Ludvigsen collection II-10. 13. Left-lateral view of carapace, paratype, GSC 29457, Ludvigsen collection II-10. 14. Right valve, holotype, GSC 29456, Ludvigsen collection II-10. Flaccivelum sp., (p. 21). Right valve, lateral and ventral views, figured specimen, GSC 29509, from the Michelle Formation, Ludvigsen collection II-10. Parabolbina sp., X 40 (p. 17). Ventral and left-lateral views of a carapace, figured specimen, GSC 29449, from the Michelle Forma- tion, Ludvigsen collection II-10. Infractivelum acuminatum n. gen., n. sp., from the Prongs Creek Formation (p. 21). 19. Tecnomorphic left valve, paratype, GSC 29506, Ludvigsen collection V-3. 20. Small teenomorphic left valve, paratype, GSC 29507, Ludvigsen collection V-3. 21. Heteromorphic right valve, holotype, GSC 29503, Ludvigsen collection V-3. 22. Tecnomorphic right valve, paratype, GSC 29505, Ludvigsen collection V-4. 23. Heteromorphic right valve. paratype, GSC 29504, Ludvigsen collection V-3. Infractivelum spiculosum n. sp., from the McCann Hill Chert (p. 22). 24. Tecnomorphic right valve, paratype, USNM 173766, USGS collection 7033-SD. 25. Tecnomorphic left valve, paratype, USNM 173765, USGS collection 7033-SD. 26. Tecnomorphic left valve, paratype, USNM 173767, USGS collection 6492-SD. 27. Heteromorphic left valve, holotype, USNM 107342, USGS collection 6492-SD. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 8 h "} Roy , »" , OBOTRITIA?, CHIRONIPTRUM, FLACCIVELUM, PARABOLBINA, AND INFRACTIVEL UM FIGURE 1, 2, 8. 4-9. 10-15. 16-24. PLATE 9 [All figures X 30] Kirkbyella (Kirkbyella) sp. (p. 24). Left valve, figured specimen, USNM 173775, from the McCann Hill Chert, USGS collection 7037-SD. Hanaites linearis n. sp., from the Prongs Creek Formation, Ludvigsen collection V-3 (p. 24). 2. Tecnomorphic left valve, paratype, GSC 29477. 3. Heteromorphic right valve, holotype, GSC 29478. Hanaites brevis n. sp., from the McCann Hill Chert, USGS collection 6492-SD (p. 25). 4. Tecnomorphic right valve, paratype, USNM 173776. 5. Left-lateral view of small teenomorphic carapace, paratype, USNM 173778. 6. Tecnomorphic left valve, paratype, USNM 170340. 7-9. Right-lateral, dorsal, and ventral views of heteromorphic carapace, holotype, USNM 173777. Hana'tes spinosus n. sp. (p. 25). 10. Small teenomorphic right valve, paratype, USNM 173781, from the McCann Hill Chert, USGS col- lection 7033-SD. 11. Right-lateral view of heteromorphic carapace, paratype USNM 173782, from the McCann Hill Chert, USGS collection 6492-SD. 12. Dorsal view of heteromorphic carapace, paratype, USNM 173783, from the McCann Hill Chert, USGS collection 6492-SD. 13. Heteromorphic left valve, holotype, USNM 173780, from the McCann Hill Chert, USGS collection 6492-SD. 14. Tecnomorphic left valve, paratype, GSC 29479, from the Michelle Formation, Ludvigsen collection II-10. 15. Tecnomorphic left valve, paratype, USNM 170339, from the McCann Hill Chert, USGS collection 6492-SD. Subarctichites serratulus n. sp. (p. 27). 16. Right-lateral view of holotype, USNM 173784, from the McCann Hill Chert, USGS collection 6492- SD. 17. Dorsal view of holotype. 18. Ventral view of holotype showing rows of spinules. 19. Interior of broken carapace, paratype, USNM 173785, from the McCann Hill Chert, USGS collection 6492-SD, showing thin walls and narrow duplicature. 20. Left valve, paratype, USNM 170350, from the McCann Hill Chert, USGS collection 6492-SD. 21. Interior of left valve, paratype, GSC 29483, from the Prongs Creek Formation, Ludvigsen collec- tion V-4. 22. Right valve, paratype, GSC 29486, from the Prongs Creek Formation, Ludvigsen collection V-3. 23. Interior of left valve, paratype, GSC 29484, from the Prongs Creek Formation, Ludvigsen collec- tion V-38. 24. Interior of right valve, paratype, GSC 29485, from the Prongs Creek Formation, Ludvigsen col- lection V-3. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 9 f" KIRKBYELLA, HANAITES, AND SUBARCTICHITES FicurES - 1-5. 9-12. 183. 14. PLATE 10 [All figures X 30] Libumella sp. cf. L. discoides Rozhdestvenskaya, 1959 (p. 27). 1. Lateral view of carapace, figured specimen, GSC 29480, from the Prongs Creek Formation, Ludvigsen collection V-3. 2. Lateral view of carapace, figured specimen, GSC 29481, from the Prongs Creek Formation, Lud- vigsen collection V-3. 3. Lateral view of carapace, figured specimen, USNM 170344, from the McCann Hill Chert, USGS collection 6492-SD. 4,5. Lateral and dorsal views of larger carapace, figured specimen, USNM 173789, from the McCann Hill Chert, USGS collection 7082-SD. Libumella sp. cf. L. circulate Rozhdestvenskaya, 1962 (p. 28). 6. Right valve, figured specimen, GSC 29482, from the Prongs Creek Formation, Ludvigsen collection V-3. 7,8. Left valve, exterior and interior views, figured specimen, USNM 173790, from the McCann Hill Chert, USGS collection 70832-SD. Neoaparachites? sp. aff. N.? insericus (Rozhdestvenskaya, 1962) (p. 28). 9,10. Right valve, exterior and interior views, figured specimen, USNM 173791, from the McCann Hill Chert, USGS collection 6492-SD. 11,12. Right-lateral and dorsal views of carapace, figured specimen, USNM 173792, from the McCann Hill Chert, USGS collection 7032-SD. "Aparchites" sp. aff. 'A." auriculiferus Rozhdestvenskaya, 1962 (p. 28). Lateral and dorsal views of broken carapace, figured specimen, USNM 173793, from the McCann Hill Chert, USGS collection 7932-SD. PROFESSIONAL PAPER 825 PLATE 10 GEOLOGICAL SURVEY "APARCHITES®" AND fin § m C < RA x & Z & - 3 S s: -] FIGURES 1-4. 5, 6, 9. ife. 10,11. 12-14. 15. 16, 17. 18. 19-24. 25-27. 28. PLATE 11 [All figures X 30] Bairdia dejecta n. sp. (p. 30). 1. Right-lateral view of incomplete carapace, paratype, USNM 173801, from the McCann Hill Chert, USGS collection 7037-SD. 2-4. Right-lateral, left-lateral, and dorsal views of holotype, USNM 173800, from the McCann Hill Chert, USGS collection 7037-SD. Bairdiolites? sohni n. sp. (p. 31). 5,6. Right-lateral and dorsal views of holotype, USNM 173803, from the McCann Hill Chert, USGS collection 7087-SD. 9. Interior of right valve, paratype, USNM 173804, from the McCann Hill Chert, USGS collec- tion 7037-SD. Beecherella? sp. (p. 33). Dorsal and lateral views of right valve, figured specimen, USNM 173808, from the McCann Hill Chert, USGS collection 7037-SD. Bairdia sp. cf, B. leguminoides Ulrich, 1891 (p. 30). 10. Right-lateral view of carapace, figured specimen, GSC 29508, from the Prongs Creek Formation Ludvigsen collection V-5. 11. Left valve, figured specimen, USNM 173799, from the McCann Hill Chert, USGS collection 7038- SD. Acanthoscapha sp. (p. 31). Right-lateral, left-lateral, and dorsal views of poorly preserved carapace, figured specimen, USNM 173807, from the McCann Hill Chert, USGS collection 7037-SD. Rectobairdia sp. (p. 31). Left valve, figured specimen, USNM 173802, from the McCann Hill Chert, USGS collection 6492-SD. Shidelerites typus Morris and Hill, 1951 (p. 82). 16. Right-lateral view of holotype, USNM 116420, from the Waldron Shale of Indiana. 17. Right-lateral view of paratype, USNM 116421a, showing anterior spine. Shidelerites yukonensis n. sp. (p. 32). Right-lateral view of carapace, holotype, GSC 29440, from the Prongs Creek Formation, Ludvigsen collection V-8. Eukloedenella recta n. sp. (p. 29). 19,20. Left-lateral and dorsal views of carapace, paratype, USNM 173794, from the McCann Hill Chert, USGS collection 7037-SD. 21. Left-lateral view of carapace, paratype, GSC 29445, from the Michelle Formation, Ludvigsen collection II-10. 22. Right valve, paratype, GSC 29446, from the Michelle Formation, Ludvigsen collection II-11. 28. Right valve, holotype, GSC 29443, from the Michelle Formation, Ludvigsen collection II-10. 24. Dorsal view of carapace, paratype, GSC 29444, from the Michelle Formation, Ludvigsen collec- tion II-10. Poloniella (Framella) sp. aff. P. (F.) scheii Weyant, 1968, from the McCann Hill Chert, USGS collection 70837-SD (p. 30). 25. Left valve, figured specimen, USNM 173796. 26. Left valve, figured specimen, USNM 173798. 27. Left valve, figured specimen, USNM 173797. Eukloedenella soloensis n. sp. (p. 29). Right valve, holotype, GSC 29442, from the Prongs Creek Formation, Ludvigsen collection V-3. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 11 BAIRDIA, BAIRDIOLITES?, BEECHERELLA, ACANTHOSCAPHA, RECTOBAIRDIA, SHIDELERITES, EUKLOEDENELLA, AND POLONIELLA (FRAMELLA) FiGurES 1-3. 5-7. 8, 9. 10, 11. 12. 13-25. PLATE 12 [Al figures X 30] "Tricornina" caurina n. sp. (p. 33). f Lateral, posterior, and dorsal views of right valve, holotype, GSC 29448, from the Prongs Creek For- mation, Ludvigsen collection V-3. Tricorninae sp. (p. 34). Broken left valve, figured specimen, GSC 29510, from the Michelle Formation, Ludvigsen collection 1-3. Bicornina sp. (p. 34). 5,7. Left-lateral and dorsal views, figured specimen, USNM 173810, from the McCann Hill Chert, USGS collection 7037-SD. 6. Left-lateral view of carapace, figured specimen, USNM 173809, from the McCann Hill Chert, USGS collection 6492-SD. Berounella sp. aff. B. minuta Blumenstengel, 1970 (p. 34). Right-lateral and dorsal views, figured specimen, USNM 173811, from the McCann Hill Chert, USGS collection 7037-SD. Bairdiocypris? sp. cf. B.? cordiformis Rozhdestvenskaya, 1959 (p. 35). 10. Right-lateral view of carapace, figured specimen, GSC 29450, from the Prongs Creek Formation, Ludvigsen collection V-3. 11. Right-lateral view of small carapace, figured specimen, USNM 173840, from the McCann Hill Chert, USGS collection 7037-SD. Bairdiocypris sp. (p. 35). Right-lateral view of carapace, figured specimen, GSC 29476, from the Prongs Creek Formation, Lud- vigsen collection V-3. Kuresaaria blackstonensis n. sp. (p. 35). 13. Right-lateral view of small carapace, paratype, USNM 173818, from the McCann Hill Chert, USGS collection 6492-SD. 14. Interior of left valve, paratype, USNM 173816, from the McCann Hill Chert, USGS collection 7037-SD. 15. Dorsal view of carapace, paratype, USNM 173817, from the McCann Hill Chert, USGS collec- tion 7032-SD. 16. Interior of left valve, paratype, GSC 29490, from the Michelle Formation, Ludvigsen collec- tion II-13, showing hinge. 17. Interior of right valve, paratype, GSC 29492, from the Michelle Formation, Ludvigsen collec- tion II-13, showing hinge and muscle scar. 18. Right view of carapace, holotype, GSC 29487, from the Prongs Creek Formation, Ludvigsen collection V-3. 19. Right valve, paratype, GSC 29491, from the Michelle Formation, Ludvigsen collection II-13. 20. Left valve, paratype, GSC 29488, from the Michelle Formation, Ludvigsen collection II-13. 21. Broken specimen, paratype, GSC 29493, from the Michelle Formation, Ludvigsen collection II- 13, showing thickness of shell. 22. Interior of left valve, paratype, GSC 29489, from the Michelle Formation, Ludvigsen collec- tion II-13, showing muscle scar and ventral stop ridges. 23. Right view of corroded carapace, paratype, USNM 173815, from the McCann Hill Chert, USGS collection 6492-SD, showing possible mural pores replaced by silica. 24,25. Right-lateral and left-lateral views of large carapace, paratype, USNM 170343, from the Mc- Cann Hill Chert, USGS collection 6492-SD. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 12 "TRICORNINA'! BICORNINA, BEROUNELLA, BAIRDIOCYPRIS?, BAIRDIOCYPRIS, AND KURESAARIA FIGURES - 1-4. 5-7. 8-11. 12-17. PLATE 13 [All figures X 30] Camdenidea sp., from the McCann Hill Chert, USGS collection 7047-SD (p. 33). 1. Right valve, figured specimen, USNM 173813. 2,83. Left-lateral and interior views, figured specimen, USNM 173814. 4. Left-lateral view of carapace, figured specimen, USNM 173812. Praepilatina sp. aff. P. praepilata sibirica Polenova, 1970, from the McCann Hill Chert, USGS collection 7487-SD (p. 36). 5. Small right valve, figured specimen, USNM 173825. 6. Interior of small right valve, figured specimen, USNM 173826. 7. Large left valve, figured specimen, USNM 173827. Bairdiohealdites? scapulatus n. sp., from the McCann Hill Chert (p. 86). 8,9. Right-lateral and dorsal views of carapace, holotype, USNM 173819, USGS collection 7033- SD. 10. Interior of left valve, paratype, USNM 173824, USGS collection 7037-SD, showing muscle scar. 11. Interior of left valve, paratype, USNM 173820, USGS collection 6492-SD, showing char- acter of dorsal margin. Voronina sp. cf. V. invente Rozhdestvenskaya, 1962, from the McCann Hill Chert (p. 37). 12-14. Left-lateral right-lateral, and dorsal views of carapace, figured specimen, USNM 173828, USGS collection 7032-SD. 15,16. Right-lateral and interior views, figured specimen, USNM 173829, USGS collection 6492-SD. 17. Left-lateral view of large carapace, figured specimen, USNM 173830, USGS collection 7032-SD. GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 13 CAMDENIDEA, PRAEPILATINA, BAIRDIOHEALDITES?, AND VORONINA FicuUrRES - 1, 2. 8, 4. 5-11. 12-14. 15, 16. 174, 18. 19. 20. 21. 22. 28. 24-26. 27-29. PLATE 14 [Al figures X 30] Eriella? sp. (p. 39). 1. Right valve, figured specimen, USNM 173834, from the McCann Hill Chert, USGS collection 7037-SD. 2. Right valve, figured specimen, GSC 29452, from the Michelle Formation, Ludvigsen collection I-3. Microcheilinella? sp., from the Prongs Creek Formation, Ludvigsen collection V-3 (p. 39). 8. Right-lateral view of carapace, figured specimen, GSC 29515. 4. Dorsal view of carapace, figured specimen, GSC 29514. Neocraterellina? crescentifera n. sp., from the McCann Hill Chert, USGS collection 6492-SD (p. 39). 5,6. Right-lateral and ventral views of carapace, paratype, USNM 173836. 7. Left valve, paratype, USNM 170336. 8,9. Right-lateral and dorsal views of carapace, holotype, USNM 173835. 10. Interior of left valve, paratype, USNM 173837. 11. Interior of left valve, paratype, USNM 173838. Cavellina (Invisibila)? sp., from the McCann Hill Chert, USGS collection 7037-SD (p. 37). 12,13. Right-lateral and left-lateral views of carapace, figured specimen, USNM 173848. 14. Interior of right valve, figured specimen, USNM 173849. Ostracode indet. 3 (p. 40). 15. Right-lateral view of carapace, figured specimen, GSC 29517, from the Prongs Creek Forma- tion, Ludvigsen collection V-3. 16. Dorsal view of carapace, figured specimen, GSC 29516, from the Prongs Creek Formation, Ludvigsen collection V-8. Newsomites? sp. (p. 31). Right-lateral and dorsal views of carapace, figured specimen, USNM 173847, from the McCann Hill Chert, USGS collection 7037-SD. Barychilina? sp. (p. 36). Right valve, figured specimen, GSC 29451, from the Michelle Formation, Ludvigsen collection I-3. Ostracode indet. 1 (p. 40). Broken right valve, figured specimen, GSC 29511, from the Michelle Formation, Ludvigsen collection I-38. Trypetera%® sp. (p. 37). Broken right valve, figured specimen, GSC 29447, from the Michelle Formation, Ludvigsen collection II-13. Ostracode indet. 2 (p. 40). Left valve, figured specimen, USNM 173839, from the McCann Hill Chert, USGS collection 6492-SD. Pachydomellid indet. 2 (p. 38). Left valve, figured specimen, USNM 173846, from the McCann Hill Chert, USGS collection 7037-SD. Pachydomellid indet. 1 (p. 38). 24. Left valve, figured specimen, USNM 173832, from the McCann Hill Chert, USGS collection 7087-SD. 25,26. Right-lateral and dorsal views of carapace, figured specimen, USNM 173833, from the McCann Hill Chert, USGS collection 7032-SD. Tubulibairdia sp. (p. 38). 27,28. Right-lateral and dorsal views of broken carapace, figured specimen, USNM 173831, from the McCann Hill Chert, USGS collection 7032-SD. 29. Right-lateral view of carapace, figured specimen, GSC 29475, from the Prongs Creek Forma- tion, Ludvigsen collection V-3. * U. S, GOVERNMENT PRINTING OFFICE : 1973 O - 509-058 GEOLOGICAL SURVEY PROFESSIONAL PAPER 825 PLATE 14 ERIELLA?, MICROCHEILINELLA?, NEOCRATERELLINAQ, CAVELLINA (INVISIBILA)?, NEWSOMITES?, BARYCHILINA, TRYPETERA?, TUBULIBAIRDIA, AND OSTRACODES INDET & ENS 7 DAY P to | v. ¥ 2 G Geomorphology and Quaternary Geology of the Glaciated Ohio River Valley- A Reconnaissance Study GEOLOGIéAL SURVEY PROFESSIONAL PAPER 826 C Geomorphology and Quaternary Geology of the Glaciated Ohio River Valley- A Reconnaissance Study By LOUIS L. RAY GEOLOGIC A L SURVEY PROEESSIONA L PAPER 826 A study of the geomorphic development and drainage modifications resulting from the Quaternary glaciations of the Ohio River valley, from above Cincinnati, Ohio, to Louisville, Ky. UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON :- 1974 UNITED STATES DEPARTMENT OF THE INTERIOR ROGERS C. B. MORTON, Secretary GEOLOGICAL SURVEY V. E. McKelvey, Director Library of Congress catalog-card No. 74-600081 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 - Price $2.65 (paper cover) Stock Number 2401-02556 CONTENTS Page Page Abstract.... :.:. .... canes. ovis tar a ina sal ain vat 1 _ Quaternary history of the Glaciated Ohio River valley-Con introduction :s. 9M cine tsl at. 2 Glaciation 42 Regional 4 Drainage modifications resulting from the Illinoian Pre-Quaternary geology 7T Claciation Anais ags. rails.... 51 Bedrock formations and structure ..................... 7 Sangamon interglacial time ..................... ...... 56 Physiographic description 7 Wisconsin Olaciation 58 Pre-Quaternary geomorphic and drainage development .. 11 Valley trains and terraces resulting from the Wiscon- Quaternary history of the Glaciated Ohio River valley ...... 21 gin Glaciation . :;. %. rll . 58 Nebraskan Glaciation ie, 22 The terrace of Tazewell age :.................. 58 Drainage modifications resulting from the Nebraskan Lacustrine deposits and terrace remnants of Claciation. :; ;:: sallie arie: rear ail wae ia y 29 Tazewell age in valleys tributary to the Drainage modifications above the Manchester divide 30 sluiceways of Wisconsin age ................ 61 Drainage development between the Manchester divide The post-Tazewell (Cary) terrace .............. 64 and the Loulsville area. 22, 31 Post-Cary alluvial history ......................... 65 Aftonian interglacial 33 Flood plain of the Glaciated Ohio River valley .......... 65 Kansan Glaciation 84 The Falls of the Ohio.. ..?. ras. .s serier 69 Drainage modifications resulting from the Kansan Big Bone Lick, Kentucky anais a 70 Glaciation .; >. ri: sis.. yas cy tee: rae aan a magie 89 . References cited.... el.:... T1 Yarmouth interglacial time... .........2..s..0..0....... 40. Index :.... ¢.. :t .y sir tier.. cali dana tien. a 75 Prate 11. 12-15. 16. 17. 18. 19. 20. 21. 22. w f- © Mp fo No f ILLUSTRATIONS Page Generalized sketch map of glacial deposits in the Ohio River valley is-. itll. a ial In pocket Topographic maps of the Ohio River valley, Indiana and Kentucky .... ................................... In pocket Map of geomorphic subdivisions of the Ohio River valley.. .l... oy... a viale ok 3 Index to U.S. Geological Survey topographic quadrangle maps of the Ohio River valley.. aie. a 5 Map of drainage basins directly tributary to the Glaciated Ohio River valley region . :...... mii l...... gs 6 Generalized geologic map of the Bluegrass region and adjacent areas in Indiana, Kentucky, and Ohio ...... .... 8 Mop of preglacial drainage basin of the upber Teays River 12 Sketch maps: 6. Major preglacial drainage channels in the vicinity of Cincinnati, Ohio 2..;......2.2.. .. ..o ie, a ovde 13 7. Proglacial- drainage in southwest ~>". g -s .tt. tons.. alll ceils oue tia gens 14 8. An interpretation of preglacial drainage of the Teays-Mahomet, Ohio, and other rivers according to Fowke, Malott, Wayne and others -. ::. . .. ..... fs.. oul lr oal ak ats oen. sa t oan caer 15 9. An interpretation of preglacial drainage of the Teays-Mahomet, Ohio, and other rivers according to Leverett. Fenneman, Stout: and others. -a.. ..... al lol. lia coin ios aii 16 10. Preglacial channel of the northeast-flowing Kentucky River .......................2..2222222........., 17 Composite stratigraphic section at the Greater Cincinnati Airport ............;........................00..... 27 Topographic maps showing glacial drift of Illinoian age: 15... Upper Rast Bend Bottom point Bar ..... ste. sls cl on n t rea aas, age ae 44 18. North of Rising Sun-Ind .._. it. +. .oa% sa f faoi ..o 1 cnl Ii eae mene ande anal aon o agi 45 14. Mexico Bolfom point _s. ss . Stolen (ons Crile. . seco rv are . ae aan oin ee 46 15 Boltom-point bar.. a..... 55 0. soles. onal. iaa e t act L au 47 Sketch map of main drainage channels of the Cincinnati region immediately before Illinoian time .......... ... 51 Sketch map of main drainage channels of the Cincinnati region after the Illinoian Glaciation ~......}.;; ...s... 52 Diagram of terrace and flood plain profiles of Ohio River valley 2 rears renia ran rive nde ta nato aint 59 Remnants of dissected terrace in lower Gunpowder Creek valley *.. me.. rana rana nad anal al. sag, 62 Remnants of dissected terrace in lower valley of Little Kentucky River ............l..........2....2..0.0........ 63 Lower Greet Miami River valley in1951 . ._........;..... ...oh. st Woll Ol te 67 bower Great Miami River walley in: 1001 ._. . . .... .n uum. cht suet cesta ttt ain en. ae 68 I IV i CONTENTS TABLE Page TABLE 1. Two-year flood altitudes along the Ohio River before construction of high-level dams .......................... 66 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY-A RECONNAISSANCE STUDY By Louis L. Ray ABSTRACT The Glaciated Ohio River valley extends from above Cincinnati, Ohio, to Louisville, Ky. In this sector of the river valley, continuous deposits of glacial drift are present on both sides of the valley, in- dicating that at least one of the glaciations of Quaternary time crossed the site of the present river. In pre-Quaternary time, the drainage pattern along the Glaciated Ohio River valley was wholly unlike that of today. Orientation of streams was largely dependent on bedrock lithology and structure, which in the Bluegrass region were dominated by the Cincinnati arch and by the subsidiary Jessamine dome, superimposed on the crest of the arch. Drainage from the Bluegrass region was to the north, between the divides produced by cuestalike outcrops of the dipping, erosion-resistant Silurian formations along the east and west flanks of the Cincinnati arch. These formations are readily recognizable as divides along the present Glaciated Ohio River valley at Manchester, Ohio, and at Madison, Ind. To the north, along the gently plunging crest of the Cincinnati arch, the Silurian formations dip so slightly that they crop out in a broad belt and show no well-defined es- carpments; thus, no barrier was formed between the north-flowing streams from the Bluegrass region and the great Teays-Mahomet River, to which they were tributary. Drainage from the Bluegrass region between the flanking es- carpments of the Silurian formations was by three streams-the Manchester River from the east, the Licking River from the south, and the Kentucky River from the west. These streams converged near Hamilton, Ohio, and continued north as an important tributary to the Teays-Mahomet River. West of the north-south Silurian escarpment and divide that crossed the present Ohio River valley at Madison, Ind., preglacial drainage was to the west along the course of a small northern branch of the Salt River of Kentucky. This minor stream, flowing independently to the Mississippi embayment, was later to become integrated into the stream that is today the main stem of the Ohio River. For this reason, the preglacial Ohio River is said to have had its headwaters on the back slope of the prominent Silurian cuesta, the so-called Laughery es- carpment, at Madison, Ind. In the Glaciated Ohio River valley region, the four major glaciations of Quaternary time caused drastic and highly complex modifications of the regional drainage system and the integration of the several drainage basins into a single basin, that of the present Ohio River. Each glaciation played a distinct and definite role in these complex drainage changes. Perhaps the greatest and most drastic drainage changes were those produced by the invasion of the first ice sheet, the Nebraskan, the most widespread of all the Quaternary ice sheets in this area. This, the first great derangement of drainage, obliterated the Teays-Mahomet River in Ohio, integrated the drainage above the divide at Manchester, and forced the impounded waters of the ice-dammed streams across both the Manchester and the Madison divides. Northward drainage from the Bluegrass region was largely blocked, and a great ice- marginal stream, the early Ohio River, was produced. When the Nebraskan ice sheet had disappeared from the Glaciated Ohio River valley, the newly integrated Ohio River is believed to have followed once again the preglacial channel of the Manchester River from the Manchester divide to the vicinity of Hamilton, Ohio, where, after joining the Licking River, it followed the sinuous course of the Kentucky River to the southwest, with a flow opposite the Kentucky River's preglacial drainage direction. From there, it crossed the Madison divide and followed the course of a preglacial northern branch of Salt River-a course generally similar to that of today, except in the vicinity of Cincinnati, where drainage skirted north of the area of the present city in a preglacial loop of channelways. During the succeeding Aftonian interglacial time, the headwater tributaries of the larger streams dissected the uplands, so relief along the drainageways was increased. Meanwhile, the glacial drift on the undissected uplands was subjected to intensive weathering in place. When the Kansan ice sheet advanced from the northeast, it deposited glacial drift locally on uplands covered by the earlier, deeply weathered drift of Nebraskan age and in valleys that had been cut below the drift-mantled upland. Reconnaissance studies indicate that in the region of the glaciated Ohio River valley the Kansan ice sheet was less widespread than the Nebraskan, for the ice crossed the river valley only in the vicinity of Cincinnati and west of Madison. The ice is > believed to have extended south of the river only for a short time. Resultant drainage modifications were minimal when compared with those produced by the earlier, Nebraskan, and the later, Illinoian, ice sheets. However, as in the Nebraskan age, the drainage channel around the area of the present city of Cincinnati was temporarily blocked. As a result, waters in the valleys of the Licking River and the integrated drainage from the east were ponded. The impounded waters may have temporarily overtopped a col between the Licking River and drainage to the west in the vicinity of the Anderson Ferry along the present Ohio River, west of Cincinnati. Several other drainage bypass channels may have served temporarily to drain the waters impounded in the Ohio and its tributary valleys. Yarmouth interglacial time began with the withdrawal of the Kan- san ice sheet. It was the longest and most important of the three Quaternary interglaciations and a time of long-continued and deep weathering and of active stream erosion. Pre-Yarmouth glacial deposits of Nebraskan and Kansan age are so deeply weathered and so lacking in surface expression, presumably because of surficial erosion, that they are readily distinguishable from the less deeply weathered post-Yarmouth deposits of Illinoian and Wisconsin age, which may re- tain either wholly or in part vestiges of their original surface expres- 2 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY sion. Although the deep weathering of pre-Yarmouth deposits facilitates their distinction from post-Yarmouth deposits, it prohibits their designation as either Nebraskan or Kansan where only one drift is exposed. Only where two deeply weathered drifts are exposed in stratigraphic succession and are separated by either a pronounced un- conformity or a well-defined paleosol, can the Kansan and Nebraskan deposits be distinguished. Stream entrenchment of the bedrock valleys during Yarmouth time is generally referred to as "Deep Stage" erosion. At the time of greatest stream incision during "Deep Stage" time, local relief was at a maximum; later in Quaternary time, the "Deep Stage" valleys were alluviated, thereby reducing the local relief. By the close of Yarmouth time, local relief was greater than at any other time during the Quaternary. Therefore, the configuration of the Illinoian, the third great ice sheet to invade the Glaciated Ohio River valley region, was not like that of the earlier ice sheets; the ice was split into two distinct lobes-the Clermont of southwest Ohio and the Jackson of south-central Indiana. The well-known Chestnut Ridge morainic complex in Jackson County, Ind., is interpreted as a border feature along the east margin of the Jackson lobe. Presumably, the Illinoian ice sheet was prevented by the local relief from invading most of southeast Indiana south of the present border of the Wisconsin ice sheet. Nevertheless, its impact on the formation of the present Ohio River valley was great. Through a series of complex changes, the drainageway looping to the north around Cincinnati was finally abandoned, and the present channel of the Ohio River between the mouths of the Little and Great Miami Rivers was established, as was the present lower course of the Great Miami River. At the close of Illinoian time, the present course of the Glaciated Ohio River valley had been formed. The Clermont lobe of the Illinoian ice sheet moved into the region of the Glaciated Ohio River valley from the northeast and crossed the valley a few miles above Cincinnati. There it invaded the Kentucky hill lands, forcing drainage from upstream to use briefly the bypass channels in Kentucky that are now prominent terrain features. To the north and west, the ice was deflected in its forward movement by the steep west walls of the broad chutelike valley now in part occupied by the Great Miami River. The ice, lacking sufficient energy to surmount the valley walls and spread over the relatively undissected uplands, was readily diverted as an ice tongue down the broad valley to the Ohio and thence down the Ohio valley to the vicinity of the mouth of the Kentucky River. Vestiges of this ice tongue are present as scattered isolated masses of glacial drift in protected sites along the valley walls, especially along the inner margins of the walls and immediately downstream from the sharp bends of the bedrock valley. Only at one point is there a well-developed kame terrace and a prominent apron of outwash debris adjacent to the valley wall. Glacial drift of Illinoian age can be distinguished by its relatively modest depth of weathering as compared with depths of weathering of pre-Yarmouth glacial deposits, by its local vestiges of original surface configuration, and by its presence on the uplands as well as in the valley bottoms. When the ice sheet of Illinoian age disappeared from the region of the Glaciated Ohio River valley, the valley was freed of direct association with glacial ice for the last time; although ice of Wisconsin age closely approached the valley, it did not actually invade i€. The Sangamon, the last of the three Quaternary interglacial times, is relatively unimportant to the history of the Glaciated Ohio River valley; during Illinoian time the river channel had been stabilized, so during Sangamon time little change could be accomplished except through weathering of the surficial deposits and through stream degradation. Like all interglacial times, the Sangamon was characterized by stream degradation-the major streams were largely engaged in clearing their valleys of fluvioglacial deposits, and the tributary streams, in their headwater reaches, were engaged in dissec- tion of the adjacent uplands. When Sangamon profiles of weathering are superimposed on the previously weathered surficial deposits of Kansan and Nebraskan age, it is difficult or impossible to separate the Sangamon from earlier profiles of weathering. The last ice sheet to invade the region of the Glaciated Ohio River valley was the Wisconsin. Areally it was much less extensive than ice sheets of earlier glaciations, for it failed to reach the main Ohio River valley at any point, although a small frontal ice tongue protruded to within a few miles of the Ohio River's main stem at Cincinnati. Despite its lack of direct connection with the Glaciated Ohio River valley, the Wisconsin ice sheet had a profound effect on the valley, which served as a major sluiceway for glacial melt water and fluvioglacial debris which entered the Ohio from the Great Miami River valley and from other tributaries upstream. No melt water or debris, however, entered the Ohio River valley along the south margin of Indiana between the mouths of the Great Miami and Wabash Rivers. Aggradation during advances of the fluctuating Wisconsin ice sheet and degradation during retreats led to the formation of two prominent terraces along the Ohio River. The highest and oldest, composed of remnants of the great outwash train of Tazewell age, lies above the highest flood levels and provides sites for urban and industrial expan- sion; it is characterized by low surficial sand dunes and is an excellent source of gravel and ground water. A terrace of less economic impor- tance is slightly lower than the Tazewell terrace and above the present river flood plain. The flood plain represents the last event in the geomorphic history of the Glaciated Ohio River valley. In tributary valleys, terrace remnants underlain by lacustrine silty clays are cor- relative with the Tazewell terrace and are the result of deposition in the tributary valleys ponded by the outwash train in the main valley. The lower terrace is poorly represented in the tributary valleys. INTRODUCTION The Ohio River, formed by the confluence of the Monongahela and Allegheny Rivers at Pittsburgh, Pa., flows in a generally southwest direction for 981 river miles' to join the Mississippi River at Cairo, Ill., an air- line distance of only 546 miles. With a drainage basin of more than 200,000 square miles, the Ohio is the major tributary to the Mississippi from the east. The mean an- nual flow of 250,000 cubic feet per second for the Ohio River is, however, greater than the mean annual flow of 180,000 cubic feet per second for the main stem of the Mississippi River at the point of confluence of the rivers. The Ohio River valley is separable into two major parts, an upper and a lower (fig. 1). The upper Ohio River valley, as defined here, is entrenched in the un- glaciated and dissected Allegheny Plateau and in the part of the Outer Bluegrass region in southern Ohio and northern Kentucky (Fenneman, 1938). Although some, perhaps all, of the Bluegrass region in Ohio may have been glaciated in early Quaternary, probably Nebraskan, time (Ray, 1969), this possibility is not yet confirmed. Therefore, the downstream limit of the up- per Ohio River valley is arbitrarily defined in this report as the point below which continuous deposits of glacial drift are now recognized on both sides of the river Distances along the Ohio River are given in river miles below Point Bridge, Pittsburgh, Pa., the zero mile established by the Corps of Engineers, U.S. Army. INTRODUCTION 90 86° 82° 42° I I Mile 981 Mile 440 Mile O t LOWER OHIO VALLEY [ UPPER OHIO VALLEY Q | | $ | | | | | Alluviated Mile 725 _ Mile 625 Glaciated | valley IConstricted valley | | - valley | | | I | | | § I | | 40 |- | | | | | a < | | ‘ Z | F I | | I | | | | Bt 38°- 3 u m a u m © 3 T> o 100 200 MILES E | i | | = I I I I o 100 200 KILOMETERS 36° | | Figure 1.-Geomorphic subdivisions of the Ohio River valley. valley-near Mile 440, about 30 miles upstream from Cincinnati, Ohio (fig. 1). For almost a century the upper Ohio River valley region has been known for spectacular high-level valleys below the general upland surface and commonly 200 feet or more above the present stream levels. These high- level valleys, the dismembered remnants of a great preglacial drainage system, are an integral part of the history of the present Ohio River drainage basin. However, because the upper Ohio River valley is not part of the present field study, information on it that is utilized in this report has been derived from published studies. The lower Ohio River valley, from Mile 440 to its confluences with the Mississippi River valley at Mile 981, is more varied than the upper river valley and is divisible into three distinct sectors (fig. 1). First is the Glaciated sector from Mile 440 to a point immediately downstream from Louisville, Ky. Because the point farthest downstream at which the valley was crossed by Quaternary glaciers cannot be precisely determined, an arbitrary downstream limit for the Glaciated Ohio River valley has been placed at Mile 625, below Louisville. Near this point the Ohio River enters a narrow, deep, and sinuous gorgelike valley, which forms the second sector, here termed the Constricted Ohio River valley. This sector extends from Mile 625 to Mile 725, near Tell City, Ind., and is unglaciated. The river emerges at Mile 725 from its constricted valley into a broad unglaciated, alluviated valley with extensive bottomlands, back of which rise low rounded valley walls. Although this third sector has a few reaches that are narrow and bounded by steep bluffs, it is here defined as the Alluviated Ohio River valley and extends from Mile 725 to Mile 981 at the confluence of the Ohio and Mississippi Rivers at Cairo, IIF: In an attempt to present an overall geomorphic history of the present river and its relation to the 4 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY regional development of the landscape and to the Quaternary glaciations, reconnaissance studies were made between 1956 and 1967 of the lower Ohio River valley and the adjacent countryside. A detailed study along a part of the unglaciated and alluviated valley has served as a background for an understanding of many of the problems and regional interpretations (Ray, 19652). Brief papers, published during the progress of the regional study, have pointed out important observations and preliminary interpretations (Ray, 1957, 1960, 19632, b 1964, 1965a, b, c, 1966, 1967, 1969; Leighton and Ray, 1965). The Glaciated Ohio River valley, with which this report is concerned, is of prime importance for an un- derstanding of the entire river system. In earlier studies by others, the intimate relationship of the Ohio River valley to the sequence of Quaternary glaciations and to the effect of these glaciations on the geomorphic history of the valley and adjacent regions has not been ade- quately clarified. This has led to confusion in the inter- pretive histories of the glaciated sector of the valley as well as of the unglaciated upper and lower valleys (fig. 1), which, although not overridden by the ice, were nevertheless drastically affected by the fluctuations of the ice sheets. Field investigations consisted primarily of an ex- amination of surficial deposits both within and adjacent to the Ohio River valley and a study of the sequential development of these deposits as related to the regional geomorphic history. Within the bedrock river valley, terrace sequences were studied, and glacial deposits were identified and related to the glacial and alluvial history. Special attention was given to the weathering, regional distribution, and position of the pre-Wisconsin glacial deposits in an attempt to formulate a rational ~ glacial history that could be related to both the river and the regional landforms. Results are presented with the knowledge and hope that future detailed field and laboratory studies of the surficial deposits will augment and perhaps modify the interpretations presented here. Some of these interpretations deviate widely from the commonly accepted beliefs and are presented only after careful weighing of the evidence; others confirm inter- pretations suggested by earlier workers. Maps used during field reconnaissance studies were U.S. Geological Survey 7%-minute topographic quadrangles, scale 1:24,000 (fig. 2). Specific localities referred to in this report can be found on these quadrangle maps. The writer is indebted to the late Dr. M. M. Leighton, Chief Emeritus, Illinois State Geological Survey, and Consultant, U.S. Geological Survey, for his many visits to the writer in the field during the progress of the pre- sent study. His keen and critical field observations, com- ments, and suggestions based on his long familiarity with Quaternary problems were especially helpful. For 1 month during the summer of 1956, the writer was ably assisted in the field by E. G. Hasser, whose quick grasp of the problems led to a more efficient utilization of time allotted to field study. The writer, however, assumes full responsibility for all interpretations presented in this report. REGIONAL SETTING The present course of the Glaciated Ohio River valley (fig. 3) is a broad asymmetric loop opening to the south to encompass that part of Kentucky sometimes referred to as the "Northern Peninsula." Although the river is large, its bedrock valley, except in the vicinity of Louisville, is fairly narrow, ranging in width from less than half a mile at Anderson's Ferry (Mile 477.5, Burlington quad., Kentucky-Ohio) to slightly more than 2 miles near Rising Sun, Ind. (Mile 504, Rising Sun quad., Kentucky-Indiana). Above the Louisville area the river is entrenched well below the adjacent uplands. Valley walls are characteristically precipitous, in places rising more than 400 feet above river level. Straight reaches commonly have terraced bottomlands along only one side; valley walls rise almost from the river's edge along the opposite side as mural escarpments of seemingly horizontal stratified bedrock, irregularly notched by small V-shaped creek valleys. Straight reaches alternate with bends, where the convex banks have extensive terraced point bars of agriculturally rich bottomlands. Opposite these point bars, valley walls rise sharply almost from the banks of the river. Streams directly tributary to the Glaciated Ohio River valley from the north (fig. 3) have small drainage basins except for the Great Miami River (5,290 sq mi) and the Little Miami River (1,770 sq mi). Similarly, there are only two major tributaries from the south, the Kentucky. River (6,990 sq mi) and the Licking River (3,660 sq mi). In general, the small tributaries from the north are more steeply graded than those from the south. For a few miles west of Madison, Ind., some of the small tributaries from the north have their steep gradients in- terrupted by small waterfalls. Of these, the waterfalls of the Clifty Creek basin (Madison West quad., Indiana- Kentucky, and Clifty Falls quad., Indiana) are best known. Immediately west of Madison (fig. 3) the divide between those creeks draining directly to the Ohio and those draining west to the Wabash River is less than a mile from the bluffs of the Ohio River valley. Runoff northwest of this divide, so close to the Ohio River, must flow, therefore, for about. 300 miles through the Muscatatuck, White, and Wabash Rivers to reach the main stem of the Ohio at the southwest tip of the State of Indiana. ithology and ional character and is reg 1 1 TINC 85° ing bedrock and on the 40 MILES de through which the river flows and to which imately dependent on the 1 timately related. 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Modified from Speer and Gamble (1965). PRE-QUATERNARY G+OLOGY ¥ geomorphic history of the landscape before the first glaciation of Quaternary age, because the present Glaciated Ohio River valley has been in large part formed by glacial modification of the preexisting drainage network. PRE-QUATERNARY GEOLOGY BEDROCK FORMATIONS AND STRUCTURE Bedrock cropping out in the region of the Glaciated Ohio River valley consists of a thick sequence of in- terbedded Paleozoic shale, siltstone, limy shale, shaly limestone, limestone, and dolomitic limestone that ranges from Middle-Ordovician to Mississippian in age (fig. 4). Between the Appalachian coal basin on the east and the Eastern Interior coal basin on the west, these formations are gently bowed into a broad low anticlinal structure, the Cincinnati arch. The northeast-southwest trend of the arch in the Bluegrass region (fig. 4) is roughly parallel to the trend of the belt of Appalachian deformation, suggesting that the arch may have formed during the Appalachian deformation in late Paleozoic time. The late Paleozoic history of the Cincinnati arch has been lost through erosion and removal of a possible covering of strata of Pennsylvanian age; thinning of the older formations toward the crest of the anticline in- dicates, however, that the structure antedates the Ap- palachian deformation and may have resulted from sub- sidence of the coal basins to the east and west rather than from uplift of the arch itself. (Moore, 1986; Stout, 1941; Lockett, 1947; King, 1951). Two domal structures have been superimposed on the crest of the Cincinnati arch-the Nashville dome in Tennessee and the Jessamine dome in Kentucky. The Cincinnati arch and the subsidiary Jessamine dome, which lies about 80 miles south of Cincinnati, are the dominant structures in the Glaciated Ohio River valley region and are intimately related to the bedrock out- crops and the landscape along the river. Erosion of the Jessamine dome has produced an irregular concentric outcrop pattern of Paleozoic for- mations. In the center, the oldest formation, limestone of Middle-Ordovician age, crops out in a somewhat ovate area whose long axis trends north, roughly parallel to the crest of the Cincinnati arch in this region. The Mid- dle Ordovician is surrounded by younger limestone and shale of Late Ordovician age in a belt of irregular width. This outcrop belt is widest to the north, where strata dip 10 feet or less per mile parallel to the crest of the Cincin- nati arch, and is progressively narrower to the south along both the east and the west flanks of the dome, where strata dip 20 to 30 feet per mile away from the crest of the arch. Where the gorge of the present Ohio River transversely crosses the broad crest of the arch at Cincinnati, extensive excarpments of Upper Ordovician limestone and shale along the valley walls show nearly horizontal stratification. Along the south margin of the Jessamine dome, Upper Ordovician formations crop out only in a narrow belt (fig. 4). Surrounding the outcrop belt of strata of Late Ordovi- cian age are similar belts of successively younger Silurian, Devonian, and Mississippian limestone and shale that dip gently away from the structural high. Only to the north are the belts of concentric outcrops in- complete in this region; there, the Devonian and Mississippian formations are absent. East and west of the area of this report, in the Appalachian and Eastern Interior coal basins, respectively, strata of Pennsylvan- ian age crop out. Whether strata of Pennsylvanian age formerly extended over the Cincinnati arch and have been removed by later erosion is not definitely known, but the possibility has been considered likely, and cor- relations across the structure have been attempted (Wanless, 1939). In the long post-Paleozoic-pre-Quaternary interval, no conclusive evidence has been reported of bedrock for- mations that would indicate a marine submergence of the area. Presumably the region remained positive dur- ing Mesozoic and Cenozoic time and was subjected only to subaerial erosion. Whatever geologic events took place can be interpreted only indirectly through a reconstruction of the geomorphic history and an evalua- tion of the related surficial deposits. PHYSIOGRAPHIC DESCRIPTION General summaries of the physiography and geomorphic history of the region adjacent to the Glaciated Ohio River valley have been provided by Malott (1922) for Indiana, by Miller (1919) and McFarlan (1943) for Kentucky, and by Fenneman (1916, 1938) for Ohio. Each used the Ohio River valley as a political and physiographic boundary. Although con- venient, such a boundary is arbitrary and has led to dif- ficulties in presenting a uniform description or a regional geomorphic history. The Glaciated Ohio River valley has commonly been used to designate the boundary between two major physiographic provinces-the Interior Low Plateaus (Bluegrass section) and the Central Lowland (Till Plains section) as defined by Fenneman (1931, pl. 1; 1988). Despite the fact that glacial drift of pre-Wisconsin age has been recognized in Kentucky south of the Ohio valley for many years (Ray, 1966), the drift has been ignored because it is of limited areal extent and is largely devoid of surface expression and generally so thin that its effect on the landscape is negligible. As pointed out by Thorn- bury (1965), delineation of the provincial boundary by separation of the glacially controlled topography from the bedrock-controlled topography would be more GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY 0 10 2|0 310 4|0 SIO MILES I I I I I 0 10 20 30 40 50 KILOMETERS EXPLANATION Devonian Upper Ordovician | Silurian Pennsylvanian Mississippian :| Middle Ordovician FicurE 4.-Generalized geologic map of the Bluegrass region and adjacent areas in Indiana, Kentucky, and Ohio. Modified from the Indiana (Indiana Geol. Survey, 1956), Kentucky (Jillson, 1929; Kentucky Geol. Survey, 1954), and Ohio (Bownocker, 1947) State geologic maps and from other scattered sources. A PRE-QUATERNARY GEOLOGY 9 satisfactory but less convenient. Only the glacial drift of Wisconsin age, however, has a marked topographic ex- pression and is of sufficient thickness to partly or whol- ly obscure the bedrock-controlled topography (Malott, 1922). Because the glacial drift of pre-Wisconsin age does not mask the bedrock-controlled topography, the provincial boundary used in this report is placed at the outer, or southern, limit of the till and morainic complex of Wisconsin age in southwest Ohio and southeast In- diana (fig. 4). As a result, the entire Glaciated Ohio River valley and the adjacent countryside, which is mantled by glacial drift of pre-Wisconsin age, are placed in the Bluegrass part of the Interior Low Plateaus province (fig. 4). Miller (1919), Fenneman (1938), McFarlan (1943), Thornbury (1965), and others have delimited the Bluegrass part of the Interior Low Plateaus province in slightly different ways. The Bluegrass region as defined in this report is broadly interpreted to encompass that area extending from the center of the Jessamine dome west, south, and east to the inward-facing escarpment developed on formations of Mississippian age and north to the southern limit of glacial drift of Wisconsin age (fig. 4). Throughout this area the topography is largely bedrock controlled. On the basis of lithology and attitude of the bedrock formations, the Bluegrass region is divisible into two distinct regions comprising several physiographic units. The classic Bluegrass region, commonly designated the Inner Bluegrass region, is the fertile rolling plain of deep residual soils formed on the almost flat lying, thinly bedded, and partly phosphatic limestone and shale of Middle Ordovician age that crop out in the center of the Jessamine dome. It is a broad upland, having altitudes generally near 1,000 feet, and is appreciably dissected only where it has been deeply trenched by major streams. Since its formation, the upland surface appears to have been slightly lowered by the solution of bedrock, which has been accompanied by the formation of the characteristic rich residual soils. The Outer Bluegrass region surrounds the Inner Bluegrass and extends outward to the bounding escarp- ment of the Bluegrass region. It is characterized by diverse topography; lithology and structure in successive concentric belts of outward-dipping for- mations of Late Ordovician, Silurian, Devonian, and Early Mississippian age determine the distinctive topography of several irregular terrain units (fig. 4). Where outcrop belts are widest, the characteristic topography is best developed. This is especially true along the west flank of the Cincinnati arch, both north and south of the Glaciated Ohio River valley. There, the pre-Wisconsin glacial deposits are so thin that they do not mask the basic bedrock control of the topography. The area underlain by thinly bedded limestone and shale of Late Ordovician (Eden) age is, where un- dissected, an upland of low relief. Its altitude is general- ly comparable to that of the Inner Bluegrass and ranges from about 800 to about 1,000 feet. In large part it is topographically similar to the Inner Bluegrass, but residual soils developed from bedrock and from glacial drift of pre-Wisconsin age are thinner and less fertile. Adjacent to the major streams, which are now en- trenched several hundred feet below the general upland surface, a mature topography of steep-sided narrow rocky and relatively infertile ridges and elongate spurs has resulted from deep dissection and headward erosion of tributaries. Only the even skyline of the dissected areas indicates the existence of the former upland sur- face. f That part of southeast Indiana underlain by the Upper Ordovician formations has been termed the Dearborn upland by Malott (1922). In his description of this area, which is comparable to the Outer Bluegrass of Ken- tucky, he pointed out that it extends eastward into Ohio and southward into Kentucky and that it is obscured to the north by the mantle of thick glacial deposits of Wisconsin age. Surrounding the central core of exposed Ordovician formations is an almost continuous belt of Silurian for- mations whose outcrop in the Bluegrass section is widest on the flanks of the Cincinnati arch, just south of the limit of glacial drift of Wisconsin age (fig. 4). Farther south, the belt of outcrop becomes progressively narrower as the Silurian formations become thinner. Along the south margin of the Outer Bluegrass, out- crops of the Silurian formations are absent, for, as reported by McFarlan (1943), the formations of Silurian age are cut out by the progressive overlap of Middle Devonian formations onto formations of Late Ordovician age. j Inasmuch as the Silurian formations are generally more resistant to erosion than the underlying Ordovi- cian formations, a well-defined cuesta has formed along the inner margin of the west-dipping Silurian for- mations on the west flank of the Cincinnati arch south of the Wisconsin glacial boundary. This prominent north-trending cuesta is a well-developed drainage divide in Indiana and for about 15 miles south of the Ohio River in northern Kentucky. In Indiana it is known as the Laughery escarpment (Malott, 1922). West of the Silurian cuesta, an erosional plain of slight relief has formed in Indiana and northern Ken- tucky by the stripping of the overlying, less erosion resistant formations of Late Devonian and Early Mississippian age from the underlying more resistant Lower Devonian and Silurian formations that dip west and southwest at approximately 15 feet per mile. The 10 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY general surface of this physiographic unit of the Outer Bluegrass, almost parallel to the dip slope of the for- mations, has been named and described in Indiana by Malott (1922) as the Muscatatuck regional slope. He noted (p. 86) that "across the Ohio River in Kentucky it [the Muscatatuck regional slope] is well represented and is usually considered a part of the Bluegrass Region." The drainage divide along the Laughery escarpment marks the east edge of the regional slope in Indiana and separates drainage to the west from that of the Dear- born upland to the east (fig. 3). In Kentucky, as the for- mations of Silurian age become progressively thinner, the drainage divide, so well defined north of the Ohio River in Indiana, disappears (figs. 3 and 4). At Madison, Ind., at the east edge of the Muscatatuck regional slope, the Ohio River transects the north- trending Laughery escarpment and drainage divide in a deep and narrow valley with precipitous walls. Downstream, to the southwest, where the Ohio River crosses the Muscatatuck regional slope, valley walls re- main precipitous but are somewhat lower. Streams generally flow in conformity with the regional slope (Culbertson, 1908, 1916), which in places they have deep- ly dissected, leaving interstream areas as gently sloping upland flats. In places, the larger streams have cut through the Silurian formations into the Upper Ordovi- cian strata (fig. 4). Near the poorly defined west margin of the regional slope, erosional remnants of the over- lying limestone and shale of Devonian age are present on the interstream flats. The gently west dipping bedrock of Silurian age and the related dip slope, the Muscatatuck regional slope, are in marked contrast to the Dearborn upland to the east, which is underlain by the almost flat lying Ordovi- cian beds near the crest of the Cincinnati arch. The Muscatatuck regional slope descends from an altitude of slightly more than 900 feet at its east margin, at the crest of the Laughery escarpment, to merge on the west along an indefinite margin with a broad lowland near 500 feet in altitude-a descent of almost 400 feet in about 25 miles. The lowland at the foot of the regional slope is formed on a belt of easily eroded limestone, shale, and siltstone of Devonian and Mississippian age. Although the physiographic unit is best represented north of the Ohio River valley, where it has been described and named the Scottsburg lowland (Malott, 1922), it extends for a few miles south of the river in the vicinity of Louisville, Ky. (MecFarlan, 1943). Elsewhere, control of the topography by this belt of bedrock outcrop is less well defined, and the lowland is poorly developed. The west boundary of the Scottsburg lowland is the prominent Knobstone- Muldraugh Hill escarpment, which marks the outer boundary of the Bluegrass region. Two major streams flowing down the Muscatatuck regional slope-the combined Muscatatuck-East Fork of White River and the combined Ohio-Salt River-cross the Scottsburg lowland and plunge into deep valleys cut through the Knobstone-Muldraugh Hill escarpment (figs. 3 and 4). On the lowland, small creeks tributary to these major streams flow in courses roughly parallel to the general north-south axis of the lowland, and their headwaters are separated by inconspicuous divides. The pre-Wisconsin glacial deposits that mantle most of the Scottsburg lowland north of the Ohio River appear to have had little effect on bedrock control of the topography. The general relations of the lowland to the Wisconsin glacial deposits, however, long ago suggested to Collett (1882) that the lowland was once part of an an- cient river valley-a sluiceway for glacial melt-water torrents draining to the Ohio River. No field evidence has been found to support this suggestion. The conspicuous inward-facing Knobstone-Muldraugh Hill escarpment of siltstone, shale, and sandstone, capped by resistant limestone of Mississippian age, almost completely encircles and delimits the Bluegrass region south of the limit of the Wisconsin glacial deposits. It is best developed, however, along the west flank of the Cincinnati arch in Indiana, where it separates the Scottsburg lowland from the Norman up- land (Malott, 1922) to the west. In Indiana it rises in places more than 500 feet above the Scottsburg lowland and is reported by Malott (1922) to be the most promi- nent topographic feature of the State. South of the Ohio River in Kentucky, the escarpment, known as Muldraugh Hill, is a nearly continuous topographic feature that delimits the Bluegrass region. Where the escarpment has been dissected by stream erosion, an irregular belt of projecting spurs, flat-topped outliers, and steep-sided knoblike hills has formed, producing a terrain wholly unlike that of the Bluegrass. This belt, locally known as "The Knobs," is excluded from the Blugrass region. According to the interpretation here proposed, the Glaciated Ohio River valley lies wholly within the glaciated part of the Bluegrass section of the Interior Low Plateaus province. Its sinuous course crosses the Cincinnati arch-Jessamine dome structure and all physiographic units of the Bluegrass region except for the Inner Bluegrass on the structural crest of the Jessamine dome. Below Louisville, the river leaves the Bluegrass region through a deep gorge cut into the Knobstone-Muldraugh Hill escarpment and the upland to the west. At the head of this gorge the Glaciated Ohio River valley becomes the Constricted Ohio River valley (fig. 1). The escarpment names, Muldraugh Hill in Kentucky and Knobstone in Indiana, have been combined for use in this report (fig. 4). PRE-QUATERNARY GEOLOGY 11 PRE-QUATERNARY GEOMORPHIC AND DRAINAGE DEVELOPMENT The long interval between deposition of the youngest known marine formation in the Bluegrass region in late Paleozoic time and the invasion of the northern part of the region by the earliest ice sheet of Quaternary age lacks tangible stratigraphic evidence that can be used to reconstruct a sequence of geologic events. Lack of marine sediments of Mesozoic and Cenozoic age has led to the generally accepted belief that since late Paleozoic time this area has been continuously above sea level and subject to subaerial erosion. The history of this area is, therefore, geomorphic and of necessity begins with the oldest recognizable landforms and their associated un- consolidated deposits. These are the high-level fluviatile sands and gravels and the widespread rolling uplands which, near major streams, are commonly so deeply dis- sected that they are represented now only by relict up- land flats, ridge crests, and isolated hilltops with locally accordant altitudes. Relief on the rolling upland surface is generally not more than 100 to 200 feet. This ancient surface, now at an altitude generally be- tween 900 and 1,000 feet or more in the Inner Blugrass, is the Lexington peneplain of Campbell (1898). Although somewhat lower in altitude, it has been correlated regionally with the Highland Rim peneplain of Hayes (1899) by Malott (1922) for Indiana, by McFarlan (1943) for Kentucky, and by Fenneman (1938) and Thornbury (1965). Despite the fact that this surface has been assigned different ages, it is believed to have been formed by middle Tertiary, presumably late Miocene, time (Ray, 1965a, p. 21-22). Formation of this gently rolling upland of low relief required regional uplift to destroy the environment of marine sedimentation and to initiate an environment of subaerial erosion. This may have begun in late Paleozoic, perhaps post- Pennsylvanian time, although evidence is lacking. Inthe Bluegrass region, where the Cincinnati arch and Jessamine dome structures had been outlined, the regional uplift set the stage for long-continued subaerial erosion. Reduction of the Bluegrass region to a surface of moderately low relief that truncated bedrock struc- ture was dependent upon the rock characteristics and the erosional capacity of the streams, whose drainage may have been directed, for the most part, to the Mississippi embayment several hundred miles to the southwest. Whether the regional uplift was preceded by other periods of uplift and erosion is not known, although the possibility has been suggested (Campbell, 1898; Fenneman, 1938). Suffice it to say that by late Miocene time the Bluegrass region appears to have been a surface of moderate relief that truncated the regional bedrock structure and was perhaps only a few hundred feet above sea level. Continued differential erosion, aided by solution of the Ordovician formations, produced a broad shallow basin rimmed on the east and west flanks of the regional structure by inward-facing escarpments of the more erosion-resistant formations of Silurian age. Along the north margin of the basin, dip of bedrock across the gently north-plunging crest of the Cincinnati arch is so low that the almost horizontal Silurian formations crop out today in a broad belt with no well-defined escarp- ment. Along the south margin of the basin, where for- mations of Silurian age are absent, an escarpment capped by erosion-resistant limestone of Mississippian age (fig. 4) presumably formed contemporaneously. Although the characteristics of the drainage net on this ancient surface are not precisely known, streams of low gradient may have flowed in wide sinuous shallow valleys with broad low interstream divides (Fenneman, 1938). In that part of the Bluegrass region circumscribed by the escarpment of formations of Silurian age, drainage appears to have been generally to the north, ex- cept in the southwestern part, where drainage was to the west. A regional uplift, initiated in late Miocene-early Pliocene time, is postulated to have raised the surface of low relief, resulting in rejuvenation of stream activity. The uplifted surface appears to have been tilted in part to the west and southwest and in part to the north and northwest (Fenneman, 1938; Horberg, 1950; Thornbury, 1965). At this time there may have been no drastic rearrangement of the earlier drainage net; rather, the major stream pattern may have continued with only minor readjustments, stream entrenchment, and valley widening. Stream entrenchment into the upland surface was described by Butts (1904, p. 3), who noted that bedrock terraces or benches in the Allegheny Plateau were "rem- nants of a former broad valley floor bounded by high steep walls***". He suggested that "It has been customary to call such a broad valley floor a gradation plain," but that "for the sake of brevity, the term strath is here introduced***," and "the name Parker is adopted because the strath is well preserved at Parker on the Allegheny***." Since first proposed by Butts, the con- cept of the Parker strath has been extended regionally (Fenneman, 1938; Stout and others, 1943; Thornbury, 1965) and has at times been referred to as an "incipient" or "partial peneplain" stage formed below the uplifted Lexington surface in post-Miocene, presumably Pliocene, time. 4 In Parker (Pliocene) time, major streams, such as the Kentucky and Licking Rivers, flowed across the Ordovi- cian formations in the broad shallow basin of the Bluegrass region and cut valleys in places as much as 150 to 200 feet below the gently rolling Lexington sur- 12 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY face. At the same time, stream erosion produced the to the complex history of the present Ohio River from Muscatatuck regional slope west of the north-trending the ancient drainage systems prior to the advance of the Laughery escarpment defined by the Silurian for- first Quaternary glaciers (James, 1888, 1891; Wright, mations on the west flank of the Cincinnati arch. Many attempts have been made to unravel the overall pattern and character of the pre-Quaternary drainage of the North Central States, especially as they are related 1890; Leverett, 1902; Tight, 1903; Fenneman, 1914, 1916; Malott, 1922; Fowke, 1933; Stout and others, 1943; Horberg, 1945, 1950; Wayne, 1952, 1956; Coffey, 1958; and others). Although it is generally agreed that a large part DN NEW YORK PENNSYLVANIA “f K inpiasa "] . % \(,OLUMBUSo// L ~«ty4 a +_ INDIANAPOLIS t. o _ ___ [Dayton/é \ Es _ lc lii ize ki ~- i n.. < ) artinsyj ~~ ~- MARYLAND , &/f Hamilton 1 4 mile "40 R ‘F ai /\\ j\ Baltimore @a 45 incinnati 4 De t . & &; \ less N Cy " $ 3 figs \) , WASHINGTON $ l Madison, b C IJ ( A2 q 2; "ES RICHMOND ®, N 5 J-] f'" KENTUCKY NORTH CAROLINA ©Asheville 0 50 100 150 MILES IL | | | I | ] I 53 T I 50 100 150 KILOMETERS 0 Ficure 5.-Preglacial drainage basin of the upper Teays River. Modified from Tight (1903). 1, Drainage basin of the main stem of the Teays River. 2, Drainage basin of the Cincinnati River, a major tributary of the Teays River. PRE-QUATERNARY GEOLOGY 13 of the present upper Ohio valley drainage, above New Martinsville, W. Va. (fig. 5), was to the north, perhaps to the Atlantic through an ancient St. Lawrence valley, many conflicting hypotheses have been formulated for the Glaciated Ohio River valley. Each is based on the presumption that the present Ohio River did not exist as a through-flowing stream until after modification of the preglacial drainage pattern by Quaternary glaciations. It is generally agreed that the master stream of the North Central States did not cross the Bluegrass region in pre-Quaternary time; rather, it skirted the region on the east and north, avoiding the structurally highest part of the Cincinnati arch-Jessamine dome structure. The first evidence cited for this master stream was an abandoned river valley in West Virginia (Wright, 1890). Referred to as the Teazes (Teays) by Wright, this an- cient abandoned valley was entrenched below the up- land surface in what has become known as Parker (Pliocene) time. Studies, especially by Tight (1903), in- dicated that the Teays River system had its headwaters in North Carolina (fig. 5) and flowed to south-central Ohio. The valley was traced by Tight to the vicinity of Chillicothe, Ohio, where it disappeared beneath a man- tle of glacial deposits. Accumulated drilling and seismic records have shown with a high degree of certainty that the valley beneath the obscuring glacial deposits extends northwest from Chillicothe, across Ohio and Indiana, to join the buried Mahomet valley of central Illinois (Stout and others, 1943; Horberg, 1945, 1950; Wayne, 1956). The combined river, here called the Teays-Mahomet, was the major stream of the North Central States and was tributary to an ancient Mississippi River that drained to the Gulf of Mexico (Horberg, 1945). Strong differences of opinion exist whether drainage of the Bluegrass section was tributary to the ancient Teays-Mahomet River to the north or was tributary to an ancient southwest-flowing Ohio River that also drained to the Mississippi embayment. Leverett (1902), Tight (1903), Fenneman (1916), Fowke (1933), Stout and Lamb (1938), and Stout, Ver Steeg, and Lamb (1943) have placed a preglacial drainage divide along the present Ohio River valley near Manchester, Ohio, about 70 river miles upstream from Cincinnati. This postulated divide is about 35 miles west of the point where the main stem of the preglacial Teays River crossed the present Ohio River valley (fig. 5). Whether the divide near Manchester separated an asymmetric Teays-Mahomet drainage basin from the basin of an an- cient Ohio River, or whether it separated drainage of the main stem of the Teays-Mahomet River from that of a major tributary, has been a matter of speculation. The ancient preglacial stream heading on the west side of the Manchester divide is the Manchester River of Fowke (1925, 1933) or the Norwood River of Stout, Ver 10 MILES 10 KILOMETERS Ficure 6.-Major preglacial drainage channels in the vicinity of Cin- cinnati, Ohio. Modified from Fenneman (1916). Steeg, and Lamb (1943). Its high-level valley is believed to have followed more or less closely the northwest course of the present Ohio River valley to the mouth of the Little Miami River valley in the east part of Cincin- nati. The preglacial net of stream valleys in the vicinity of Cincinnati (fig. 6) is well known (James, 1891; Fenneman, 1916, 1938; Thornbury, 1965). Briefly, the Manchester River of Fowke flowed up the present Little Miami River valley, its flow reversed from that of the present stream, and through the Norwood trough to join the ancient Licking River at the head of the now- abandoned trough. The north-flowing Licking River is believed to have crossed the site of the present Ohio River and continued to the north, essentially along the course now followed by the south-flowing Mill Creek through the heart of Cincinnati, to its confluence with the Manchester River. The ancient combined Manchester-Licking River continued northwest and, south of Hamilton, Ohio, joined a major stream oc- cupying the ancient broad high-level valley that is now in large part followed by the Great Miami River. Whether this major stream had a reversed flow to the north, as the Cincinnati River of Tight (1903) (figs. 5 and 6), or a flow to the south, as the Hamilton River of Stout, Ver Steeg, and Lamb (1943) (fig. 7), has been a subject of discussion for many years. According to Fowke (1898, 1900, 1925, 1933), Tight (1903), Malott (1922), Wayne (1952), and others, a preglacial drainage divide similar to that at Manchester 14 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY 84° 3o' T af I [ I -~ 3 21g AZ 210 ”I Day tony I I & %. | a* Hamilton () oY “alto 18" 1 Cincinnati [Age / ga SRC / x ( 0 E- -- - 39 / €, \ T5 'kEN % Ss > \/ TUCKY vii \ las AD ”00on River \ \7f 0 10 20 30 MILES 0 10 20 30, KILOMETERS Manchester divide ) Figure 7.-Preglacial drainage in southwest Ohio. Modified from Stout, Ver Steeg, and Lamb (1943). was present along what is now the Ohio River valley at Madison, Ind. (figs. 5 and 8). They believed that drainage east of the Madison divide had a reversed flow to the northeast up the present Ohio valley and then the Great Miami valley as the Hamilton River (same as the Cincin- nati River of Tight (1903)) to join the combined Manchester-Licking drainage near Hamilton. From there, drainage continued north as a major tributary to the ancient Teays-Mahomet River. On the other hand, Stout, Ver Steeg, and Lamb (1943), following James (1888, 1891), and Leverett (1902), placed a preglacial drainage divide near Dayton, Ohio (fig. 9). They believed that this divide would have blocked a north-flowing Hamilton River (Cincinnati River) from the basin of the Teays-Mahomet River. Therefore, they proposed that near Hamilton, Ohio, the Manchester (Norwood) River was tributary to a south-flowing Hamilton River. According to this proposal, the Hamilton River headed along a divide northeast of Dayton that separated its basin from that of the main Teays-Mahomet River; therefore, the combined Hamilton-Manchester River was forced to flow southwest along the broad valley now in large part oc- cupied by the Great Miami River to reach the preglacial Ohio River that flowed southwest, as it does today, across the Madison divide of Fowke and others (fig. 8). Resolution of the preglacial drainage pattern is thus dependent on the validity of two of the three proposed preglacial drainage divides. Each of these postulated divides is along the outcrop belt of erosion-resistant Silurian formations that dip outward from the Cincin- nati arch-Jessamine dome structure. The first divide, near Manchester, Ohio, on the east flank of the structure (figs. 5 and 7-9), separated the basin of the ancient preglacial Teays River from that of the Manchester (Norwood) River. This divide has been generally accepted and has not been the subject of con- troversy. The second divide, north or northeast of DaytonOhio (figs. 7 and 9), is presumed to have spearated the Teays River basin from drainage of the Bluegrass region. If the second divide is valid, then the third divide, at Madison, Ind. (figs 5 and 8), could not have existed, for it would have blocked the drainage to the southwest along a preglacial Ohio River valley. If, on the other hand, there was no drainage divide in the Dayton area, but a divide at Madison, as urged by Fowke (1925, 1933), Malott (1922), and Wayne (1952, 1956), drainage of most of the Bluegrass region would have been tributary to that of the ancient Teays- Mahomet system, and the headwaters of the preglacial Ohio River would presumably have been west of the Madison divide. It is essential, therefore, to consider the validity of these two important divides-the one near Dayton and the one at Madion-in order to determine the preglacial drainage o the Bluegrass region and of the Ohio River. Leverett (1902) and Fenneman (1914, 1916), following James (1891), placed the headwaters of the preglacial Ohio at the Manchester divide and believed that drainage was to the vicinity of Hamilton, Ohio, and thence to the southwest, in general following the course of the present Great Miami and Ohio Rivers to and beyond the Madison divide (fig. 9) Stout, Ver Steeg, and Lamb (1943) suggested that the broad valley leading northeast from Hamilton to the Dayton area and beyond, now occupied by the Great Miami River, formerly contained a major stream, the Hamilton River, that flowed southwest from a divide north or northeast of the Dayton area (fig. 7). They postulated that the Hamilton River was "formed by the convergence of tributaries at Dayton" (1943, p. 70), and, following Leverett and Fenneman, they believed that it continued southwest, joining the larger Manchester (Norwood) River, which headed on the Manchester divide. Norris and Spieker (1966) reviewed the two opposing _ theories of preglacial drainage (figs. 7 and 8) and of the presumed divide northeast of Dayton. On the basis of their field studies, available drilling records, and con- touring of the bedrock surface beneath the mantle of glacial deposits, they concluded (1966, p. 22) that "the PRE-QUATERNARY GEOLOGY 15 direction of flow in the Dayton area of the Teays Stage streams (south, as Stout, Ver Steeg, and Lamb state, or - north, as Wayne believed) is a matter of speculation for the time being," and, furthermore (p. 23), that "elements of both concepts may be correct." They suggested, but did not critically analyze, a theory that the Hamilton River may have initially had a southward flow which was later reversed by capture through headward erosion of a tributary of the Teays-Mahomet River. They also pointed out that possible passages known to cross the drift-mantled drainage-divide area near Dayton appear too narrow to have accommodated a north-flowing stream having a drainage basin the magnitude of the north-flowing Hamilton (Cincinnati) River system. Although Stout, Ver Steeg, and Lamb (1948, p. 68) stated that "the [Hamilton River] outlet was along the valley of the present Ohio River to where this old tributary joined the master Teays near the mouth of the present Wabash," their map (fig. 7) indicates that the Hamilton River did not join the Ohio near the present mouth of the Great Miami, but seemingly entered In- diana at the mouth of the present Whitewater River valley (fig. 3) An alternative hypothesis suggested by Durrell (1961) was that the preglacial drainage was directed to the southwest from the Hamilton, Ohio, area, to and up the present Whitewater River valley, across the Silurian cuesta (Laughery escarpment) in southeast Indiana, and along the preglacial Anderson Valley (fig. 8; Wayne, Since the study of Stout, Ver Steeg, and Lamb (1943), accumulated information has demonstrated that the Wabash River was not part of the preglacial Teays-Mahomet River system (Wayne, 1952, 1956; Thornbury, 1965) but was tributary to the preglacial Ohio (figs. 8 and 9). A 88° 86 84 | | T T ILLINOIS = I N D I A N A I OHIO l ways -Map, I 40° |- - CoLUMBUS t \ wo .. e \ f p Louisville \ > E- o w 38 |- \ m | \\3 Salt River _ c \ | 1 KENTUCKY 100 MILES I 100 KILOMETERS Ficure 8.-An interpretation of preglacial drainage of the Teays-Mahomet, Ohio, and other rivers. Modified from Fowke (1898, 1900, 1925, 1933), Malott (1922), Wayne (1952), and others. 16 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY 88° s6 84 I I ILLINOIS I INDIANA 1 7767fo 40° |- OHIO COLUMBUS - 7 / «< Manchester E / divide O > la m {l- z KENTUCKY 0 50 100 miLESs - py . ~ A 0 50 100 KILOMETERS | Ficure 9.-An interpretation of preglacial drainage of the Teays-Mahomet, Ohio, and other rivers. Modified from Leverett (1902), Fenneman (1914, 1916, 1938), Stout, Ver Steeg, and Lamb (1943), and others. 1952, 1956), a tributary of the preglacial Teays-Mahomet River. Such a drainage pattern implies the existence of a drainage divide near Dayton. Inasmuch as no mention was made of drainage from the Kentucky River basin, one cannot be certain whether Durrell inferred a drainage divide at Madison. His map (1961, fig. 2), however, indicates that the preglacial Eagle Creek in northern Kentucky flowed up the present Ohio and Great Miami River valleys to the vicinity of Hamilton, Ohio, thence on to the north, thereby implying that no divide separated this north-flowing stream from the main stem of the Teays-Mahomet River. No drainage from the east along the preglacial course of the Manchester (Norwood) River is shown on Durrell's map. Durrell's alternative hypothesis of drainage through the Whitewater River and, by inference, the Anderson Valley appears unlikely in view of Wayne's report (1952) that the preglacial Anderson Valley headed near the crest of the Laughery escarpment in southeast Indiana. The deep narrow gorge across the escarpment, now buried under glacial drift, is, according to Wayne, the result of Quaternary erosion by overflow waters from a proglacial lake that occupied Anderson Valley. If this is true, there was no continuous Whitewater-Anderson valley that could have served as a drainageway in pre- Quaternary time. Much evidence has been marshalled by Malott (1922, p. 138-139) in support of a drainage divide following the crest of the Laughery escarpment at Madison, Ind. He pointed out that the narrow steep-sided valley of the PRE-QUATERNARY GEOLOGY 17 present Ohio at Madison is obviously young and is cut below a relatively smooth and undissected upland that lacks ancient channelways across it either north or south of the present river gorge. Furthermore, he noted that fluviatile gravel deposits are absent on the upland surface in the Madison area, whereas ancient gravel deposits are reported along the high-level valleys of the preglacial Eagle Creek; the Kentucky, Licking, and Salt Rivers; and the Ohio River below Louisville. He failed, however, to distinguish between gravel deposits on the uplands And those in the high-level stream channels cut below the upland surface. o Malott (1922) and others have called attention to the fact that small tributaries of the present Ohio River between Madison and the mouth of the Kentucky River would have joined normally an ancient stream flowing northeast from & divide at Madison, but that today, a reversal of flow having resulted from Quaternary glacial modifications of the drainage, the tributaries are barbed. If, however, the argument based on the barbed drainage is examined further, it does not adequately ex- plain all tributary relations between the mouths of the Kentucky and Great Miami Rivers. Along this section of 'the Ohio River valley, some stretches have barbed tributaries, whereas other stretches have normal tributaries. This seemingly anomalous situation is readily explained, however, on the basis of the con- figuration of a high-level preglacial channel of the Ken- tucky River that drained to the northeast. Along the Glaciated Ohio River valley between Miles 488 (Lawrenceburg quad., Kentucky-Indiana-Ohio) and 541 (Vevay South quad., Kentucky-Indiana), a high-level preglacial channel can be reconstructed that was sinuous, narrow, similar to, and a continuation of the high-level preglacial channel of the Kentucky River above its present confluence with the Ohio (fig. 10; Jillson, 1946). Where the present Ohio River valley is a modified segment of the sinuous preglacial valley, tributary streams are now barbed; where the present valley is the result of Quaternary drainage modifications resulting from glaciation, tributaries now join the main valley normally. Evidence of similar barbed drainage has been recognized by Norris and Spieker (1966, p. 22) along the Great Miami River valley in southwest Ohio, suggesting that the preglacial drainage flowed north and was a continuation of the northeast-flowing Kentucky River (fig. 10), as first proposed by Fowke in 1898. For this recornaissance study, no attempt was made to map in detail the sinuous high-level channel and the associated deposits of the northeast-flowing preglacial Kentucky River. Segments of this channel were recognized by Leverett (1902) but not interpreted by him as belonging to a single sinuous upland stream channel. Jillson (1946) described an abandoned preglacial channel along the lower course of the present Kentucky River that connects the present valley of the Kentucky River with that of the Ohio. This, the Easterday channel of Jillson, is slightly more than 6 miles long and can be readily followed as a topographic depression from the Kentucky River valley up the valley of Whites Run to a col about a mile northeast of Easterday, Ky. (Vevay South quad., Kentucky-Indiana). From the col, the an- cient valley, about half a mile wide and 100 to 200 feet below the upland surface, follows the present valley of Fourmile Creek to join the Ohio River valley near Mile 541, about 5 river miles above the confluence of the pre- sent Kentucky and Ohio Rivers (Carrollton quad., Kentucky-Indiana). In the col is lodged a mass of glacial till; between the col and the present Kentucky River valley are remnants of fluviatile sand and gravel on bedrock benches above the level of the present drainage. Jillson (1946) correlated these deposits with the high- level channel deposits along the Kentucky River up- stream. The preglacial channel, continuing northeast from the mouth of the Easterday channel, roughly follows the course of the present Ohio River valley to the vicinity of Ghent, near Mile 539 (Vevay South quad., Kentucky- Indiana). There it turns in a broad are to the southeast and follows the valley of the present McCools Creek for about 2.5 miles. Turning to the southeast, up an un- named tributary valley, the preglacial channel appears 85° I I Great Miami o / 5" 10. 15 mites 45W” f - 025 | aP 0 5 10 15 KILOMETERS 0&0/ &: R 39° - > 7 ) \—Preglacial 46 Kentucky ( (Cincinnati) ) ) River Preglacial &]) Kentucky . Preglacial (Cincinnati) onl ) * \Eagle Creek Madison River * a. lis ; L/ ; 6 ( Preglacial Ghent gee“ divide 092 Preglacial \a Carroliton' T 2 divide G T >. 4 9 G i '> &. Ficure 10.-Generalized configuration of the high-level preglacial channel of the northeast-flowing Kentucky River and its relation to the valley of the present southwest-flowing Ohio River. 18 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY to have continued to the valley of Stephens Branch, following it to Stephens Creek (Sanders quad., Ken- tucky) to rejoin the Ohio River valley near Mile 582, close to the Markland Dam (Florence quad., Indiana- Kentucky). The sinuous preglacial channel is believed to have con- tinued to the northeast before swinging again to the southeast in a broad are to follow up the valley of Dry Creek into the hills back of Warsaw, Ky. (Florence quad., Indiana-Kentucky). Turning to the east, across a low col, the preglacial channel swung northeast along the present valley of Big Sugar Creek and reached the present Ohio River valley again near Mile 523 (Patriot quad., Kentucky-Indiana). Almost immediately the preglacial channel appears to have swung northeast, up the valley of the present Paint Creek, where it is presumed to have joined the preglacial channel of Eagle Creek along the South Fork of the present Mudlick Creek. The combined channels continued in a meander- ing course to the north in the now dissected hills east of the present Ohio River valley. This course is in large part poorly defined because it has been obscured by Quaternary glacial deposits and partly destroyed by subsequent erosion. The northward direction of the preglacial Eagle Creek valley led Leverett (1902) to suspect that Fowke's suggested northward streamflow might have some validity. Leverett, however, "upon further reflection and reexamination felt that doubt has arisen concerning the validity of this interpretation" (1902, p. 115). As late as 1929 he clung to the belief that "the drainage from the mouth of the Kentucky was down the present course of the Ohio at that (preglacial) time" (1920, p. 25). The concept that the channel of the preglacial northeast-flowing Kentucky River (fig. 10) was sinuous and high above the present Ohio River level was not recognized by Malott (1922) when he stressed the lack of major bevelling of the upland surface toward the pre- sent river valley at Madison, although he reported such bevelling to be present elsewhere along the Ohio, in places both above and below Madison. Furthermore, he (1922) believed that the presumed northeast slope of the bedrock floor of the present Ohio River valley above Madison was important supporting evidence for the Madison divide. This presumed slope was based on in- sufficient data and was in direct conflict with the southwest slope of the Great Miami bedrock valley, as reported by Fenneman (1914, 1916). This conflict Malott attempted to explain away on the basis of possible postglacial uplift. The slope of the present bedrock river valley is, of course, inadmissible as evidence for deter- mining the slope, and thus the flow, of the preglacial (pre-Quaternary) drainageways because the bedrock floor of the present valleys is the result of stream ero- sion of Quaternary rather than pre-Quaternary age. Gradients of the bedrock floors of the preglacial high- level valleys of Pliocene (Parker) age can be precisely determined only by detailed field studies and regional mapping. Despite the evidence for a Madison divide proposed by Malott and others, Jillson, following James (1888, 1891), Fenneman (1914, 1916), and Leverett (1902, 1929), re- jected the idea of a drainage divide at Madison and postulated that the preglacial Kentucky River followed either the course of the present Ohio River or possibly that of the Muscatatuck River to the southwest. He suggested (Jillson, 1946) that a preglacial Ohio River from the northeast flowed through the Easterday channel to join the Kentucky River in a course to the west. This interpretation was based on the belief that the bedrock floor of the Easterday channel sloped southwest at an average gradient of 1.5 to 2.5 feet per mile. If this unusually high gradient were true, the fluviatile deposits could not be interpreted as being a continuation of the high-level preglacial Irvine deposits of Campbell (1898) along the Kentucky River. To the deposits in the Easterday channel, Jillson assigned a Pliocene age but suggested a change in facies to explain that the deposits were made by a "somewhat longer, and smaller, but contemporaneous (late Pliocene) Ohio River" (Jillson, 1946, p. 31). It is well known that the course of the preglacial Eagle Creek was, like that of the preglacial Kentucky River, to the northeast, and that the diversion of its lower course to the southwest took place in Quaternary time (Leverett, 1902, 1929; Tight, 1903; Fowke, 1933; Jillson, 1949; Durrell, 1961). Jillson (1949, frontispiece map) in- dicated that north of the point of its diversion (figs. 3 and 10; Glencoe quad., Kentucky), the preglacial Eagle Creek flowed in a meandering course to join, as a barbed tributary, the west-flowing preglacial Ohio River near the present mouth of Big Bone Creek (Patriot-quad., Kentucky-Indiana). This peculiar barbed drainage and its implications are not tenable on the basis of the regional drainage pattern, although they are in agree- ment with the beliefs of Leverett (1902, 1929). In 1961, Durrell proposed (fig. 2, p. 49) that this creek, his so-called Eagle River, was a major preglacial stream that followed with reversed flow the Ohio-Great Miami (Cincinnati) River valley to the vicinity of Hamilton, Ohio, where it joined the preglacial Licking River. From this point, drainage may have continued to the north, as shown on his map, as a major tributary to the Teays- Mahomet River, or, as he suggests (Durrell, 1961, p. 51), it may have followed an alternative course up the Whitewater valley of southeast Indiana, with a flow reversed from that of the present Whitewater River (fig. 3). This alternate route was not possible during PRE-QUATERNARY GEOLOGY 19 preglacial time if the interpretations by Wayne (1952) are correct (p. 16). Field observations by the writer along and adjacent to the Glaciated Ohio River valley and his evaluation of the published studies of others have him led to the conclu- sion that the preglacial drainage of most of the Bluegrass region was, except for the drainage basins of the preglacial Salt and Muscatatuck Rivers, to the north and was tributary to the preglacial Teays-Mahomet River. The combined drainage basins, excluding the basin of Salt River, provide for a normal rather than a distinctly lopsided shape for the preglacial Teays- Mahomet basin in this region (fig. 5). It is no coincidence that the postulated three divides that controlled the drainage of the Bluegrass region in relation to the Teays-Mahomet River are on the erosion-resistant Silurian formations. Along the flanks of the Cincinnati arch, dips of the erosion-resitant Silurian formations, although gentle, are sufficient to produce a marked topographic expres- sion along the belt of outcrop, thus providing in large part for drainage control. To the north, however, in the region of the postulated drainage divide north and northeast of Dayton, Ohio, the Silurian formations that crop out across the north-plunging crest of the Cincin- nati arch are almost horizontal, having dips of nearly 5 feet per mile (Norris and Spieker, 1966). There, the topographic control of the preglacial high-level drainage by cuestas was presumably less effective than where dips are greater. The preglacial Hamilton (Cincinnati) River (fig. 8) could, therefore, flow north to form a ma- jor tributary to the main stem of the Teays River northeast of the postulated drainage divide near Dayton. No major high-level preglacial channel across the divide area, underlain by Silurian formations, has yet been identified beneath the thick mantle of glacial deposits. When and if it is identified, it will be narrow and probably steep walled, as suggested by Norris and Spicer (1958). If there was a major drainage divide at Madison, Ind. and drainage of the preglacial Kentucky and other streams to the east was tributary to the Teays-Mahomet River, then the headwaters of the preglacial Ohio River were west of the Madison divide, and the preglacial Ohio was not a tributary of the Teays-Mahomet River. Therefore, the origin of the Muscatatuck regional slope and its preglacial drainage must be determined in order to establish the position of the headwaters of the preglacial Ohio River. Formation of the Muscatatuck regional slope in In- diana was described by Malott (1922), with the implica- tion that its extension in northern Kentucky had a similar origin. He recognized that the belts of gently westward dipping and easily eroded Devonian (New Albany) and Mississippian (Borden Group) shale and siltstone have been almost wholly stripped by west- flowing streams from the underlying erosion-resistant limestone of Devonian and Silurian age. Thus, a surface formed that is almost coincident with the dip of bedrock on the west flank of the Cincinnati arch. Prior to formation of the regional slope in Indiana and Kentucky, preglacial streams-the East Fork of White River and its major tributary, the Muscatatuck River, and the Salt River-headed on the blackslope of the Laughery escarpment. The Muscatatuck regional slope, the Scottsburg lowland, and the Knobstone-Muldraugh Hill escarpment owe their formation to these west- flowing streams and their tributaries. Stream erosion during Pliocene (Parker) time progressively removed the incompetent Devonian and Mississippian formations so that the regional slope formed by downdip expansion from east to west. Meanwhile, the Scottsburg lowland and the Knobstone-Muldraugh Hill escarpment were in- itiated in Indiana and adjacent parts of northern Ken- tucky. The lowland gradually grew and the escarpment increased in height as the two features retreated westward down the dip of the bedrock. During the preglacial formation of the Muscatatuck regional slope and the Knobstone-Muldraugh Hill es- carpment, the west-flowing preglacial Muscatatuck- East Fork of White River in Indiana and the Salt River in Kentucky cut their valleys into the regional upland west of the escarpment. In preglacial time, therefore, the two major passages through the escarpment, now oc- cupied by the Muscatatuck-East Fork of White River and the Ohio-Salt River, were formed by normal stream erosion as stripping of the regional slope progressed. Such a mode of formation is in agreement with Leverett's (1929) belief that the course of the present Ohio River through the Knobstone-Muldraugh Hill es- carpment is preglacial in age, and it is directly opposed to the belief of Gray and Powell (1965, p. 5) that, "Before the Pleistocene Epoch no stream breached the Knobstone Escarpment where the Ohio River now flows %o %e ork " In Kentucky, the Muscatatuck regional slope is pre- sent as a distinct topographic feature for only a few miles south of the Glaciated Ohio River valley. The westward-flowing preglacial Salt River, though super- ficially similar to the preglacial Muscatatuck River im- mediately to the north, has had a somewhat different history. East of the Knobstone-Muldraugh Hill escarp- ment, the Salt River had three main branches: (1) a north branch, which was similar to the Muscatatuck River and which flowed down the regional slope from its headwaters along the back slope of the Laughery escarp- ment near the Madison divide; (2) a middle branch, the present Salt River; and (3) a south branch, the present 20 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY Rolling Fork, which roughly followed the poorly defined narrow lowland and knobs belt along the southwest side of the Outer Bluegrass region. Transformation of the north branch of the preglacial Salt River into the present Ohio River as the result of Quaternary glaciation is discussed later as part of the geomorphic history of the Ohio River in Quaternary time. The history of Rolling Fork is not pertinent to the history of the Ohio River and is not discussed. The mid- dle branch, the present Salt River, is, however, of es- pecial interest in that its geomorphic history bears directly on and supports the interpretation of the geomorphic history of both the Ohio and the Kentucky Rivers. Where the middle branch of the preglacial Salt River flowed across the west flank of the Cincinnati arch, the Muscatatuck regional slope is essentially lacking as a distinct terrain unit. Headwater erosion by Salt River in preglacial time captured the drainage of a north-flowing tributary of the Kentucky River, a piracy noted by Leverett (1929). Drainage of this captured tributary was abruptly diverted to the west at a point approximately 4 miles west of the main stem of the Kentucky River (McBrayer and Salvisa quads., Kentucky). High-level fluviatile deposits, such as those near Alton, Ky. (Lawrenceburg quad., Kentucky; Leverett, 1929), mark the ancient channelway of this tributary of the Ken- tucky River below the point of capture. Although Leverett (1929) suggested that the high-level deposits were probably Irvine in age, he noted that the stream piracy appeared to have taken place somewhat later than the deposition of the high-level deposits but before the main valley cutting of the Kentucky and Salt Rivers. During mapping of the nearby Tyrone quadrangle (Cressman, 1964), high-level fluviatile deposits were dis- covered 225 to 450 feet above the level of the Kentucky River. These have been correlated with the Irvine For- mation (Miller, 1925; Jillson, 1943, 1947), but at least two levels of deposits, possibly more, appear to be present. The higher deposits originally described by Campbell (1898), are related to ancient drainageways on the up- land, the Lexington surface. The lower deposits are associated with channels cut well below the upland sur- face-such as the channel at Alton, which, before cap- ture by Salt River, was tributary to the Kentucky River, and with those channels now represented by the aban- doned high-level meanders of the Kentucky River. The Wildcat meander described by Jillson (1947) is im- mediately east of the point of tributary capture by Salt River and follows Gilbert Creek from near its mouth at the Kentucky River (Salvisa quad., Kentucky) to Wild- cat Creek valley and Tyrone (Tyrone quad., Kentucky). Although this abandoned channel of the preglacial Ken- tucky River is slightly lower than the nearby deposits along the old abandoned tributary channel at Alton (Lawrenceburg quad., Kentucky), both channels are preglacial and almost comparable in age, although the piracy by Salt River may have occurred somewhat earlier than the abandonment of Wildcat meander. Both events are assigned, nevertheless, to Pliocene (Parker) time. The Easterday channel (Jillson, 1946), through which the preglacial Kentucky River flowed to and up the an- cient valley now occupied by the Ohio River, is likewise believed to be of Pliocene (Parker) age, correlative with the Wildeat and other abandoned meanders and channels along the Kentucky River. Thus, the preglacial Kentucky River valley, entrenched below the upland surface in Parker time, was graded to the northeast as a tributary of the Teays-Mahomet River, whereas, at the same time, the middle branch of Salt River was graded to the southwest across the Muscatatuck regional slope to the Mississippi embayment. Today, Salt River at the point where it captured the preglacial Kentucky River tributary has an altitude of nearly 710 feet, whereas the normal pool stage of the Kentucky River, only 4 miles to the east, is at an altitude of 483 feet-a difference of 227 feet. Since stream cap- ture, Salt River has cut down about 100 feet, whereas the nearby Kentucky River has cut to a depth of more than twice that amount. Such an anomaly in river levels and entrenchment can be explained only by the diver- sion of the Kentucky River drainage in Quaternary time across the Madison divide and into the headwaters of the north branch of Salt River on the Muscatatuck regional slope. As a result of glaciation, to be discussed later, the divide at Madison was breached and obliterated by torrents of glacial melt water in early Quaternary time, so drainage previously tributary to the Teays-Mahomet River was diverted across the divide and into the north branch of Salt River to follow its preglacial course to the Mississippi embayment. The increased volume of water provided static rejuvenation to the new through-flowing river and its major tributary, the Kentucky River, so its erosive downcutting was spectacularly increased. At this time, the main stem of the newly organized river cut into the divide area and into the Muscatatuck regional slope and regraded the preglacial channel of the river above the Madison divide. All cutting was not ac- complished at once but took place during the several Quaternary glacial and interglacial times. Because there was no significant increase in volume of flow of the small preglacial middle and south branches of Salt River, their downcutting was less active. Despite the capture of the drainage of the relatively small tributary to the old Kentucky River, Salt River and Roll- ing Fork remained only small tributaries to the newly organized great river that flowed west across the QUATERNARY HISTORY OF THE GLACIATED OHIO RIVER VALLEY 21 Madison divide to follow the preglacial channel of the north fork of the preglacial Salt River. All available evidence indicates a preglacial drainage system east of the Madison divide that was tributary to the major Teays-Mahomet River system. This concept is in accord with the beliefs proposed long ago by Fowke and Tight and elaborated by Malott (1922). Waters of the Eagle Creek and the Manchester, Licking, Whitewater, and Kentucky River basins, confluent in the vicinity of Hamilton, Ohio, are believed, on the basis of field obser- vations and literature review, to have flowed northeast to join the preglacial Teays-Mahomet River as a major tributary (fig. 8). Pregacial drainage on the regional slope west of the Madison divide was gathered into two major west-flowing streams, the combined Muscatatuck- East Fork of White River in Indiana, tributary to the preglacial Wabash River, and the Salt River in Ken- tucky. These followed courses through the Knobstone- Muldraugh Hill escarpment that were formed in preglacial (Pliocene) time. The present course of the Ohio River entrenched into the Muscatatuck regional slope follows the course of a small preglacial branch of Salt River. Thus, drainage west of the Madison divide belonged to a preglacial basin whose waters were funnelled into the Gulf of Mexico in a course indepen- dent of the Teays-Mahomet River. The Madison divide, separating the preglacial Teays-Mahomet basin from the preglacial Salt River basin, was, therefore, of major importance. Evaluation of the preglacial fluviatile deposits, to which the name Irvine has been loosely attached, in- dicates that these deposits, although generally similar in character and composition, are found at several different altitudes above the present streams and are of different ages. The Irvine gravel, as originally described (Campbell, 1898) is related to drainage on the upland, Lexington, surface. Somewhat younger deposits are pres- ent along abandoned channels and meanders of the major streams that were well entrenched below the up- land surface in Pliocene (Parker) time. Deposits at in- termediate altitudes and of intermediate age are present but have not been studied. QUATERNARY HISTORY OF THE GLACIATED OHIO RIVER VALLEY In the midcontinent area of the United States, Quater- nary time was characterized by successive advances and recessions of glacial ice sheets. Major glaciations, of which four are traditionally recognized-Nebraskan, Kansan, Illinoian, and Wisconsin-were separated by three interglacial intervals-Aftonian, Yarmouth, and Sangamon. Each event left indelible marks of its presence, from which a regional picture of Quaternary events has emerged. Along the Glaciated Ohio River valley, which roughly follows the southern limit of glaciation, the beginning of Quaternary time is marked by the effects of the first invasion by a glacial ice sheet. Until that time, conditions which characterized the late Tertiary (Pliocene) are presumed to have continued es- sentially undisturbed. The thesis presented here for the development of an integrated history of Quaternary events in the Glaciated Ohio River valley is based on the belief that each of the four major ice sheets invaded the region from the northeast. Each glacial and each interglacial time played an essential role in river and valley formation, and each has been related to the evolution of the regional terrain. Reconnaissance field studies, together with interpretations and observations of others, have been analyzed. The resultant history here presented agrees in part with, and in part diverges widely from, earlier views. Since the first geological studies were made along the Ohio River valley and adjacent regions, the general un- derstanding of Quaternary events has progressed rapid- ly. This understanding has been augmented by informa- tion from many local studies, so the interpretations presented here are believed to approach more closely a rational explanation of the developmental history of the Glaciated Ohio River valley and adjacent terrain than the earlier interpretations. Future detailed mapping and field and laboratory studies will, without doubt, clarify and define more precisely the sequence of Quaternary events. For more than a century, glacial deposits along the Glaciated Ohio River valley have been studied and age interpretations made and later modified (summarized by Ray, 1966); but not until recently have all four major glaciations been identified and reported in this area, through recognition of deposits assigned to the earliest glaciation, the Nebraskan (Leighton and Ray, 1965; Ray, 1965b, c). The evolution and modification of the Ohio River valley and the adjacent countryside from pre- Quaternary time to the present represent a complex se- quence of events unrivalled elsewhere along a great river, because the present Ohio River valley and its drainage basin are in large part the result of the Quater- nary glaciations. Without the drastic modifications produced by these glaciations, the preglacial Teays- Mahomet River system would doubtless still dominate the drainage of the north-central United States. It has been generally agreed that the first glaciation to invade the area caused disruption of the ancient Teays-Mahomet River system and integration of the several preglacial drainage basins that now constitute a large part of the present Ohio River headwaters. The age of this first glaciation, other than being presumably pre- Illinoian, has been the subject of speculation for several 22 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY decades. Tight (1903, p. 108) suggested that the glacia- tion was possibly pre-Kansan in age, although direct evidence was not available to him. Later, Stout, Ver Steeg, and Lamb (1943) suggested that inasmuch as the deep valley entrenchment, the "Deep Stage," of the Ohio and its tributaries was believed to have been ac- complished in pre-Illinoian time, the earliest glaciation was probably the one immediately preceding the Illinoian-the Kansan. Stout, Ver Steeg, and Lamb (1943), Thwaites (1946), and Wayne (1956) suggested, however, that the earliest glaciation, the Nebraskan, may have spread into Ohio, Indiana, and northern Ken- tucky. The first definitive evidence of Nebraskan drift in the area of the Glaciated Ohio River valley was presented by Leighton and Ray in 1965. (See also Ray, 1965b, c, 1969.) As early as 1890, Chamberlin (in Wright, 1890) suggested that the deeply weathered and featureless "attenuated drift," beyond the moraines of southwestern Ohio and in northern Kentucky, belonged to one or more drift sheets older than the less weathered deposits now recognized to be of Wisconsin age. Leverett (1899, 1902, 1929) unfortunately failed to recognize definitely or to establish more than one pre-Wisconsin glaciation in northern Kentucky and hesitantly reached the conclusion that, except for the widespread and isolated erratics, the older drift constituted a single deposit of Illinoian age. Brand (1934, p. 82), after review- ing the possibility of a pre-Illinoian drift, tentatively concluded that "evidence of a pre-Illinoian ice sheet in northern Kentucky is still lacking*** that the glacial material on the uplands south of Cincinnati is water-laid and not ice-laid." Belief in an Illinoian age for the glacial deposits in northern Kentucky continued (Flint and others, 1945) until the 1950's, when evidence for deposits of Kansan age appeared. Ray (1957) assigned a Kansan age to a glacial till along the Ohio River valley in northern Ken- tucky that was far more deeply weathered than un- questioned Illinoian till. In southeast Indiana, Kansan drift was reported beneath surficial deposits assigned an Illinoian age (Wayne, 1955, 1956, 1958; Gooding, 1966). In southwest Ohio, Durrell (1961) assigned a Kansan age to surficial drift more deeply weathered and dissected than nearby deposits of undoubted Illinoian age! Belief in a Kansan rather than an Illinoian age for the deeply weathered surficial drift of northern Kentucky became so well established that by 1959 almost all sur- ficial drift in that area was assigned a Kansan age, but similar deeply weathered surficial drift on the uplands of southwest Indiana, immediately across the Ohio River, continued to be assigned the traditional Illinoian 'Shown as Kansan (?) on the Glacial Map of Ohio (Goldthwait and others, 1961). See also Goldthwait and others (1965). age (Flint and others, 1959). In northern Kentucky, the Illinoian drift was almost wholly restricted to a narrow belt along the Chio River upstream from the Cincinnati area (Flint and others, 1959; Durrell, 1961). When Leighton and Ray (1965) reported two deeply weathered glacial tills separated by a paleosol in a single well-exposed stratigraphic section on the uplands of northern Kentucky, a few miles southwest of Cincin- nati, they assigned to the lower till, which overlay calcareous proglacial sediments and bedrock, a Nebraskan age. To the younger, overlying till they assigned a Kan- san age. Thus, three pre-Wisconsin ice sheets of Nebraskan, Kansan, and Illinoian age were recognized as having invaded and profoundly affected the Glaciated Ohio River valley during Quaternary time (Ray, 1965b, c). Although the last glacial ice sheet, the Wisconsin, failed to reach the river valley, it, too, disturbed the river regimen. During the three interglacial and postglacial times, a theoretical equilibrium was reestablished by the river through erosion of the bedrock valleys and their contained glacial deposits. NEBRASKAN GLACIATION The assignment of the oldest glacial deposits in northern Kentucky to a Nebraskan age immediately presents a problem, for no deposits of similar age have been reported from either southwest Ohio or southeast Indiana. There, the oldest reported glacial deposits have been assigned a Kansan age (Wayne, 1955, 1956, 1958; Durrell, 1961; Gooding, 1966). This anomalous situation can be explained by one of three possibilities: (1) glaciers of Nebraskan age did not invade southwest Ohio and southeast Indiana; (2) glacial till of Nebraskan age has been wholly obliterated or removed by subsequent glaciations; or (3) till of Nebraskan age has not been recognized as such, and some or all of the buried tills of southeast Indiana that are reported to be of Kansan age are actually of Nebraskan age, and therefore, the overlying till, long held to be of Illinoian age on the basis of Leverett's studies, may be, like that of Kentucky, in part older and of Kansan age, as implied by Rich (1956). The first possibility is untenable if the identification of till of Nebraskan age in northern Kentucky is valid. The second is unlikely. Field observations tend to confirm the third possibility. The following arguments are based on regional field reconnaissance studies of the glacial deposits and their relation to the terrain. These lead to the belief that the third possibility offers the only rational explanation of the Quaternary glaciations and the regional geomorphic history. No attempt has been made to map precise boundaries delimiting the glacial drifts of pre-Wisconsin age. The outer limit of glaciation (pl. 1) is of Nebraskan age in Ken- tucky and follows, with minor modifications, the glacial boundary of Leverett (Jillson, 1929). A generalized boun- NEBRASKAN GLACIATION 23 dary is indicated for the outer margin of the Kansan drift. This boundary is subject to revisions as detailed information becomes available; it is based largely on topographic control and on depth of weathering of the drift deposits. The outer margin of the Illinoian drift in Ohio and Kentucky follows, in large part, the published boundaries of Goldthwait, White, and Forsyth (1961) and Durrell (1961). The ice tongue following the Ohio River valley is discussed later in detail. The boundary of the Illinoian glacial drift in southeast Indiana is based on field reconnaissance and is highly generalized and subject to modification when detailed mapping has provided more information. It is, like the Kansan boundary, based largely on depth of weathering and topographic control. The outer boundary of the Wiscon- sin drift follows that of Goldthwait, White, and Forsyth (1961) in Ohio and Wayne (1958) in Indiana. The glaciated terrain mantled by deposits of Nebraskan age (pl. 1) gives no indication of its past glacial history. Whatever configuration the glacial deposits may have had has been obliterated by postdepositional weathering and erosion. Examination of the few exposures of deeply weathered deposits provides the only clue to their glacial origin. In the long time in- terval since deposition, leaching of the carbonates and decomposition of the small percentage of originally con- tained crystalline rocks has, where drainage is good, left a surficial mantle of residual silt throughout which small fragments of insoluble vein quartz, quartzite, sandstone, chert, and jasper are scattered at random. In general, weathering has progressed so far on the sur- ficial drifts, whether they are of Nebraskan or Kansan age, that no age differentiation can be made from obser- vations of shallow exposures. Separation of the deposits of Nebraskan and Kansan age is based on stratigraphic succession in the rare exposures, on the topographic position, especially near the outer boundary of the younger Kansan drift, and on the depth of weathering in a few thick drift exposures. As the ice sheet of Nebraskan age moved from the northeast into southwest Ohio and southeast Indiana to its point of maximum advance in northern Kentucky and southern Indiana, it crossed the preglacial Dearborn upland, the Muscatatuck regional slope, and the Scottsburg lowland. Only major stream valleys, such as the Teays-Mahomet and its larger tributaries, were en- trenched well below these surfaces. Deposits referred to the Nebraskan drift indicate that the ice sheet of Nebraskan age was more extensive than that of Kansan age, except in the vicinity of Louisville, Ky., and for a few miles to the north along the base of the Knobstone- Muldraugh Hill escarpment, the west boundary of the Scottsburg lowland. There, the two ice sheets may have been nearly coincident. In northern Kentucky, postdepositional dissection of the upland surface has left only remnants of the once- continuous drift sheet of Nebraskan age on ridge crests and relict upland flats. The outer boundary of the deposits, roughly mapped by Leverett (Jillson, 1929), is largely confined to relict uplands between the present bluffs along the Ohio River valley and to the drainage divide between the short creeks draining directly to the Ohio and those draining to Eagle and Harrods Creeks, a divide roughly parallel to the present river valley (pl. 1 and fig. 3). Only in the vicinity of the mouth of the Ken- tucky River and in the Louisville area is information so sparse that reconstruction of the general boundary of the Nebraskan drift is uncertain. Deeply weathered surficial till of Nebraskan age is generally exposed only in shallow roadcuts, where it commonly appears beneath a thin nonpebbly mantle of leached loess of Wisconsin age that may be a few inches to several feet thick. The till is commonly a yellow to red-brown clayey silt containing scattered siliceous pebbles. Subangular chert pebbles may be punky. A diligent search may uncover deeply weathered chert pebbles that retain glacial striations. Where 6 feet or more of till is present, as on Covington Ridge (Bethlehem quad., Indiana-Kentucky) and on the upland south of Milton, Ky. (Madison East quad., Kentucky- Indiana), "ghosts" or deeply weathered fragments of crystalline rock may be present at or near the base of the deposit. In general, the long-continued weathering has progressed through the glacial deposits so that all car- bonates have been removed by leaching and crystalline rocks have been completely decomposed. Where leaching has attacked the underlying limestone bedrock, the base of the weathered till may be poorly defined and may grade into the red-brown silty clay and angular chert residuum resulting from in situ leaching of bedrock beneath the till. Such deeply weathered deposits have been examined in shallow roadcuts on the uplands of Kentucky in the vicinity of Skylight and Goshen (Owen quad., Kentucky-Indiana), where, as Leverett (1929, p. 51) reported, glacial pebbles are imbedded in a reddish brown clayey deposit that seems to be mainly derived as a residuary product from the underlying limestone, and only to a subordinate degree supplemented by glacial material. In some of the pebbly clay the color is a more pronounced red than in the outlying districts where it is entirely of residuary character. Surficial drift in southeast Indiana, in a few poorly exposed sections on the uplands west of the Knobstone- Muldraugh Hill escarpment, was first reported by Thornbury (1932). Examination, by the writer, of the few shallow exposures of glacial drift in this area revealed a deeply weathered, noncalcareous, generally red-brown till of silty clay or clayey silt. Pebbles of weathered siliceous insoluble materials are scattered at random throughout, their abundance increasing with 24 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY depth below the land surface. Deeply weathered and decomposed crystalline rocks were observed only at depth in the thickest sections, such as in the roadcut 1 mile west of New Philadelphia (Little York quad., In- diana) at an altitude of 970 feet. Although these upland tills have been assigned the traditional Illinoian age by Thornbury (1932) and Wayne (1958), their weathering is far greater than that of un- questioned Illinoian till elsewhere. These upland deposits, referred to in the past as pre-Illinoian in age, may be either of Kansan or Nebraskan age, but depth of weathering of these deposits precludes further age differentiation. For, as can be stressed again, only on the basis of a stratigraphic sequence or differences in topographic position can drifts of more than a single age be recognized. The upland deposits west of the Knobstone- Muldraugh Hill escarpment are interpreted here to be of Nebraskan age because they are far more deeply weathered than typical Illinoian till and because the Nebraskan ice sheet elsewhere was more widespread than the Kansan ice sheet. The writer believes that here the ice of Nebraskan age was of sufficient thickness and vigor to override the Knobstone-Muldraugh Hill escarp- ment north of a point about 18 miles north of its presumed southern terminus. South of that point, where the ice may have been thinner near its terminus, the es- carpment presented a greater obstacle to the advancing ice sheet, which was unable to override it, and so was deflected along the base of the escarpment toward the preglacial Salt River gorge. Surficial glacial deposits on the Dearborn upland and Muscatatuck regional slope in Indiana have been thought to be Illinoian in age on the basis of Leverett's (1902) original interpretation. Inasmuch as the Cincin- nati soil series is widespread in southeast Indiana, es- pecially on the well-drained uplands believed to be un- derlain by till of Illinoian age, the concept has evolved that soils of the Cincinnati series are formed on and related only to drift of Illinoian age-a relationship doubted by some soils scientists (Guy D. Smith, oral commun., 1968). When a second till was recognized un- derlying the surficial till to which an Illinoian age had been assigned and on which soils of the Cincinnati series were present, the underlying till was naturally assigned a Kansan age (Murray, 1955; Gooding, 1966). Field reconnaissance and an examination of the few exposures of thick sections of glacial drift in southeast Indiana have led the writer to reinterpret the age of the deposits and to conclude that the surficial till is of Kan- san rather than Illinoian age and that the older, un- derlying till is of Nebraskan age. This interpretation is based on several factors, no one in itself definitive: depth of weathering, topographic position, total lack of topographic expression, and relationship of the tills of southeast Indiana to those of northern Kentucky and to. the less weathered, younger tills believed to be of Illinoian age within the Ohio River valley (pl. 1). Till on the Dearborn upland is in general temporarily and poorly exposed in shallow roadcuts that normally consist only of deeply weathered sandy silt containing scattered residual siliceous pebbles. As in Kentucky, the drift has been so deeply weathered in the normal ex- posure that one cannot distinguish whether it is of Kan- san or Nebraskan age. Deeply weathered crystalline pebbles and cobbles are not common except at depth. However, on the basis of the advanced weathering and resemblance to the youngest surficial till on the uplands of Boone County, Ky., the surficial till on the Dearborn upland of southeast Indiana is here interpreted to be in part of Kansan age and in part of Nebraskan age (pl. 1). As in Kentucky, drift on the upland areas where scattered surficial crystalline boulders as much as 2.5 feet in diameter are common is mapped as Kansan in age. Most of these boulders have been collected and removed from their original sites by local residents as curiosities, for ornamental display, and for driveway markers. A direct relationship between the boulders and the Kansan till cannot be demonstrated on the basis of the present studies, yet such a relationship is suggested, for such boulders do not appear to be related to either the older, Nebraskan, or the younger, Illinoian, drift- mantled surfaces of this region. In 1967 three sections on the Dearborn upland and the Muscatatuck regional slope were visited where tills of two glaciations had been described by Murray (1955) and Gooding (1966). Unfortunately, only one locality was available for suitable examination and checking. Each, however, with the aid of the original descriptions, could be interpreted as having a surficial till older than the Illinoian age suggested. The first, the Spillway section at Brush Creek Reser- voir, Muscatatuck State School (NE1/4 see. 6, T. 7 N., R. 9 E., Butlerville, quad., Indiana), was no longer well ex- posed in 1967. The surficial deposits there consist of some 5 feet of silty, sandy, noncalcareous and deeply weathered gumbolike clay underlain by 12 feet of non- calcareous till and 15 feet of calcareous till. Such an ad- vanced profile of weathering is suggestive not of an Illinoian age, as proposed by Murray (1955), but of a pre- Illinoian age. Furthermore, Murray (1955, p. 32) reported that "randomly oriented chunks of dark- yellowish-brown noncalcareous till" are incorporated in the calcareous till. This noncalcareous till was presumably derived from an older weathered till, presumably of Kansan age. If, however, the deeply weathered surficial till is of Kansan age, as interpreted here, then the weathered inclusions are older and of NEBRASKAN GLACIATION 25 Nebraskan age, and the older, underlying 1-foot-thick noncalcareous till at the base of the section (Murray, 1955, p. 32) is of Nebraskan rather than Kansas age. Although the reported 1-foot-thick till was so poorly ex- posed in 1967 that no definite conclusions could be drawn, the writer believes that it can reasonably be assigned a Nebraskan age. The second section, at the Scott County Stone Co. quarry (NE 1/4 NW1/4 see. 20, T. 3 N., R. 8 E., Blocher quad., Indiana), had undoubtedly been highly modified since it was first described by Murray (1955, p. 21). Accessible exposures along the quarry face were so bad- ly slumped that the zones and thicknesses reported by Murray had to be used in an attempt to restore the sec- tion. Fourteen feet of leached surficial deposits consist of 3 feet of sandy brownish silt underlain by 6 feet of clayey brownish gravel and 5 feet of clayey brown till. Below a depth of nearly 14 feet, Murray (1955, p. 21) reported almost 10 feet of oxidized but calcareous till and gravel. Near its base the till is thickly set with tattered and frayed wood fragments. An underlying, noncalcareous till, about 7 feet of which was reported, is compact, dark, reddish to greenish brown, and contains abundant siliceous pebbles, indicating that it was well weathered before the advent of the overlying, younger drift, despite the fact that its profile of weathering appears to have been truncated by the overriding ice sheet. The surficial deposits, because of their depth of weathering, can best be referred to a Kansan rather than an Illinoian age, and the lowest till is therefore of Nebraskan age. Gooding (1966) suggested that the two deeply weathered tills in stratigraphic succession are of Kansan age and represent two glacial advances. separated by a nonglacial period. The writer believes, however, that the time intervals represented by weath- ering in the sections described by Murray (1955) are greater than the intraglacial intervals reported by Gooding. The third section, described by Gooding (1966) at Osgood (SW. cor. see. 7, T. 8 N., R. 12 E., Pierceville quad., Indiana), was exposed during road construction in 1959. By 1967 it was so overgrown and washed that it would have been difficult to interpret had it not been for the published section (Gooding, 1966, p. 427). The basal 10 feet, resting on Ordovician bedrock, was covered when examined by Gooding and in 1967. The top of the 65-foot section of glacial drift is an eroded ridge crest 20 feet or more below the level of the nearby rolling upland, indicating the magnitude of post-depositional erosion. Although thickness of drift on the upland is not known, the exposed Osgood section may occupy a preglacial valley cut into the bedrock upland by preglacial Laughery Creek or one of its tributaries. The lowest ex- posed 10 feet of the section consists of laminated calcareous clay interpreted by Gooding (1966, p. 429) to be a lacustrine deposit that "may have been deposited in ponded waters of a tributary of the north-flowing Teays-age Eagle River, which existed along the Indiana- Ohio State line west of Cincinnati (Durrell, 1961, p. 49, fig. 2) when Kansan ice advanced into the area." The in- terpretation presented here is that the original ponding of drainage was by the first glaciation; the clay is therefore assigned a Nebraskan rather than Kansan age. In general, the clay appears to be similar to the proglacial lacustrine clay of Nebraskan age reported in the Pleasant Valley section by Leighton and Ray (1965). The Osgood section is separable into an upper 40-foot drift and a lower 25-foot drift. The upper drift, leached only to a depth of 6 feet or so, has been, because of its topographic position on a narrow ridge crest, so eroded in postdepositional time that the amount of weathering and the time involved cannot be estimated. At the bot- tom of the thin leached zone is a concentration of calcareous concretions (Gooding, 1966). These con- cretions are similar in stratigraphic position to those noted by Leverett (1902, 1929) in the surficial drift deposits at Lookout Heights, Boone County, Ky., to which he assigned an Illinoian age. This drift, however, is now believed to be of Kansan age (p. 26). The lower drift of the Osgood section is leached to a depth of only 7 feet, leading one to suspect either that its profile of weathering has been truncated or that perhaps leaching has been inhibited because the drift was deposited in a preglacial channel in which drainage was poor. On the basis of their regional relations and characteristics, the two drifts are here interpreted to be of Nebraskan and Kansan age rather than Kansan and Illinoian age, as held by Gooding. The Dabney section, 1.4 miles north of U.S. Highway 50 along the east side of Michigan Road (SW1/4 sec. 81, T. 8 N., R. 11 E., Versailles quad., Indiana), is a new sec- tion. It consists of two thin till sheets exposed in a shallow roadcut below an almost flat upland surface having an altitude of nearly 950 feet. Here, a lower, dark-brown compact calcareous but oxidized and crumbly till as much as 4 feet thick contains much chert and crystalline rock. Its highly irregular upper surface indicates an unconformity, presumably the result of proglacial stream erosion before deposition of the overlying till. Above this, 2 to 6 inches of stratified calcareous pinkish to purplish silt and sand is present below a l-inch-thick plate of silt and pebbles cemented by secondary calcium carbonate, presumably derived from leaching of the overlying till. This plate is inter- preted as the basal part of the upper till, which consists of nearly 8 feet of clayey till crisscrossed by drying cracks. The upper 6 feet or so of the section is covered and unavailable for study. Of special interest is a large 26 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY buried and deeply rotted coarse crystalline boulder about 2.5 feet in diameter, similar in size to the surficial boulders found elsewhere on drift assigned a Kansan age. As in the Osgood section, the basal concentration of calcium carbonate appears to be characteristic of drift of Kansan age. Although both the base and top of the sec- tion are concealed and unavailable for study, this relatively shallow section is interpreted, on the basis of the sum total of its characteristics, to be a truncated remnant of a lower till of Nebraskan age overlain by proglacial deposits and till of Kansan age. A shallow 4-foot exposure in a road corner near Butter Falls (NW. cor. SW1/4 see. 13, T. 3 N., R. 9 E., Madison West quad., Indiana-Kentucky), about 20 feet below the local upland surface of the Muscatatuck regional slope, consists of deeply weathered crystalline "ghost" pebbles in a bright-red to red-brown silty clay matrix containing scattered chert pebbles. The clayey matrix possibly is in part derived from glacial material and in part from weathering of the underlying limestone bedrock on which the till rests. This deeply decomposed till, like that in the vicinity of Goshen and Skylight, Ky. (p. 23), is probably of Nebraskan age. In marked contrast is the brown silty till containing randomly distributed insolu- ble siliceous pebbles that crops out 2.5 miles north along State Route 256, just east of the valley of an unnamed fork of Ramsey Creek. This silttil is similar to many other scattered surficial outcrops in southeast Indiana and is here interpreted, on a regional basis, to be of Kan- san age. The area most critical for verification of two pre- Illinoian glaciations is the relatively undissected upland in northern Kentucky, south and southwest of Cincin- nati, especially west of the Licking River in Kenton and Boone Counties (pl. 1). Because of rapid urbanization there, most exposures are only temporarily available for study, and the widespread removal of surficial deposits has not only modified the terrain but destroyed valuable evidence for determination of its glacial history. Here, where the outer margin of the ice sheet or sheets was presumably thin, possibly fluctuating, - and highly crenulated, glacial deposits of differing origins appear to be complexly intermingled. Evidence for preglacial and glacial drainageways abounds on the upland surface, now dissected by headwater erosion of creeks draining to the Ohio and Licking Rivers (Covington and Burlington quads., Kentucky-Ohio; Lawrenceburg quad., Kentucky-Indiana-Ohio). In places, glacial outwash overlies till; in others, the outwash is overlain by till. Brand (1934) reported lenses of till incorporated in out- wash deposits. . In the vicinity of Lookout Heights (Covington quad., Kentucky-Ohio), Leverett (1929, p. 12-13) observed deposits of a "fine grade of molding sand***covered by a glacial deposit, that shows a much higher degree of weathering than the Illinoian till of that region," for the deposit has no limestone, "yet the chert which accom- panies the limestone is abundant, and it probably was originally thickly set with limestone pebbles." He reported, furthermore, that near the base of the leached sand, large secondary calcareous nodules were present, suggesting that calcite had been leached from the overlying glacial drift and redeposited at depth. On the basis of the available exposures, Leverett (1929, p. 82) was led to conclude that the glacial deposit overlying the sand was possibly of pre-Illinoian (Jerseyan?) age. Ex- cellent exposures confirming Leverett's observations were temporarily available for study in 1961 during grading operations for a subdivision in Lookout Heights, about 0.4 mile west of St. Agnes Church. No exposures were available to Leverett to indicate that the "molding sand" was underlain by glacial till. Evidence for an underlying till was seen in 1961, when a till was exposed in an excavation during building con- struction adjacent to Interstate Highway 75, south of the Lookout House in Lookout Heights, about 0.6 mile southeast of the exposures similar to those described by Leverett west of St. Agnes Church. Here, a blue-gray com- pact calcareous till containing limestone and scattered crystalline rock pebbles was present at an altitude of approximately 800 feet, almost 50 feet below the crest of nearby exposures of deeply weathered silty sand, im- mediately east of the Lookout House. Thus,. in :a restricted area, a compact calcareous glacial till, whose deeply weathered upper surface is not exposed, is overlain by a deeply weathered silty sand, which is in turn overlain by a surficial till more deeply weathered than till of Illinoian age. Inasmuch as the weathering of the basal and the surficial drifts is greater than that on deposits assigned an Illinoian age, deposits of two pre- Illinoian glaciations are therefore suggested, but not proven, for the entire section may be the product of ice- marginal deposition during a single glaciation, generally referred to as Kansan in northern Kentucky, a theory favored by Schaber (1962). Further evidence for two pre-Illinoian glaciations in northern Kentucky is based on an interpretation of the geologic history of closely spaced roadside exposures near the intersection of State Roads 236 and 1834, at the northeast corner of the Greater Cincinnati Airport (Burlington quad., Kentucky-Ohio), about 7.5 miles west of Lookout Heights and 1.7 miles southwest of the Ohio River valley in northeast Boone County, Ky. (pl. 1 and fig. 11). Section A is on the northeast side of State Road 2836, about 1,000 feet northwest of the intersection with State Road 1334. Sections B and C are in a continuous exposure along the southeast side of State Road 1334, starting about 150 feet northeast of the intersection, where the state road descends sharply into the valley of Elijahs Creek. NEBRASKAN GLACIATION 27 THICK- NESS (FEET) UNIT DESCRIPTION ALTI- TUDE (FEET) 7 Wisconsin: Loess, yellow to yellow- and red-brown, leached 2-3 Kansan: Silttil and outwash, deeply weathered, light- to red-brown; gray veins; sandy; limonite- cemented zones; in places poorly bedded; in- creasingly compact and pebbly at depth; scatter- ed siliceous pebbles; iron oxide concentrations at base 5 Till, leached and oxidized, brown; pebbles of weathered crystalline rock common at base 5 Concealed and in part obliterated by post-Kansan to Wisconsin erosion Nebraskan: Silttil, leached and deeply weathered, brown; scattered siliceous pebbles 3 Till, leached and deeply weathered, clayey; "ghosts" of crystalline rock pebbles 2 2 Till, leached and oxidized, brown to dark-brown; crystalline rock pebbles increasingly less weath- ered toward base of section; a few cobbles of crystalline rock 7 1 Limestone bedrock Wisconsin Kansan Nebraskan [) y- |- 870 |-860 er t |- 850 |- 840 |- 830 -- 1000 yk—‘lOO—o‘ Figure 11.-Composite stratigraphic section at the intersection of State Roads 236 and 1334 at the northeast corner of the Greater Cincinnati Airport, Burlington quadrangle, Kentucky-Ohio. Modified from Durrell, 1965. In the vicinity of these sections, called the Airport see- tions, a dissected and gently rolling upland at an altitude of 900 to 930 feet is underlain by deeply weathered silty sand and glacial till mantled by a few inches of Wisconsin loess. This widespread upland is inter- preted as an outwash plain of Kansan age probably formed along the waning irregular margin of the ice sheet. Lacustrine deposits may have been intercalated in places with the outwash deposits, but unfortunately, grading during construction of the airport destroyed much of the original upland surface and obliterated the glacial deposits. The Airport sections (fig. 11), because of their significance in determining the Quaternary history, were carefully examined during field studies. They were also studied and briefly described by Durrell (1965), who interpreted them as representing a single deeply weathered till of Kansan age. However, this writer believes that they indicate glacial deposits of Nebraskan and Kansan ages, separated by an interglacial interval of weathering and erosion, the Aftonian. The Quaternary history of the Airport sections, as in- terpreted here, starts with the invasion of the area by the first of two pre-Illinoian ice sheets, the Nebraskan. Glacial till of Nebraskan age was deposited on the preglacial bedrock uplands of low relief (fig. 11, sees. B and C). This first till, of which about 11 feet remain, is believed to have been deeply weathered and leached of its primary carbonates prior to deposition of the over- lying till (fig. 11, see. A), here assigned a Kansan age. The 28 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY lower part of the Nebraskan till in section B contains weathered crystalline pebbles and cobbles with thick weathering rinds. Progressively higher in the section, the crystalline rocks are more and more deeply weathered and appear as "ghosts" before their final dis- appearance near the top, where only insoluble siliceous pebbles remain scattered in the silttil near the top of the glacial drift (sec. B). Thickness of the original, highly calcareous unweathered till before leaching is not known, but, on the basis of a presumed high percentage of limestone rocks and calcareous matrix, it may have been several times the thickness of the present deeply weathered residuum. After the Aftonian period of weathering, the second ice sheet, of Kansan age, invaded the uplands. Deposi- tion of till was followed by deposition of a widespread deltaic outwash plain in front of the irregular, melting, waning glacier. Till, outwash, and, perhaps, lacustrine deposits are believed to have been intermingled over a widespread area of the uplands. Kansan glacial time was followed by a long and presumably uninterrupted period of weathering and erosion that continued until deposition of a thin blanket of loess of Wisonsin age over the Nebraskan and Kansan deposits. During this time, the surficial deposits of Kan- san age were also deeply weathered, and creeks, such as Elijahs Creek, eroded headward into the upland area. The outwash deposits were dissected and stripped; in places the underlying till was removed or truncated. The Airport sections were probably stripped by erosion dur- ing this time. Section A, which is in a roadcut through a ridge between small steeply graded gullies along Elijahs Creek, is well below the level of the adjacent outwash plain. Sections B and C, also exposed along a gully in the west valley wall of Elijahs Creek, have been more deeply eroded and stripped of Kansan drift. Such a history suggests that the Airport sections provide a sequence of two pre-Illinoian glacial deposits on remnants of the preglacial upland. Although not exposed in a single stratigraphic sequence, the closely spaced sections in- dicate a composite stratigraphic succession of two deep- ly weathered pre-Illinoian glacial tills, rather than a single till whose surface irregularities may have been preserved since its original deposition in Kansan time, as implied by Durrell (1965). Leighton and Ray (1965) described a section on the up-v lands of northern Kentucky in which two pre-Illinoian tills are present in a single stratigraphic succession. The older till, on the basis of its topographic position and its relation to the regional distribution of younger glacial deposits and to the geomorphic evolution of the region, is assigned a Nebraskan age, and the overlying till, a Kansan age. This, the Pleasant Valley section, is about 5.5 miles southwest of the Airport sections. It is a road- cut, fresh in 1963, along Pleasant Valley Road 1.8 miles northwest of its junction with U.S. Highway 42 at Sugartit (Union quad., Kentucky). In this vicinity the gently rolling upland has been dissected by a network of small shallow creek valleys, and surface features give no indication that the country has been glaciated. Pleasant Valley section [Composite section modified from Leighton and Ray (1965)] Thickness Wisconsin: (feet) Loess, leached, yellow to yellow-brown ------------------ 2-8 Kansan: Silttil, leached and deeply weathered; thin gray soil zone at top; a few scattered siliceous pebbles ----------------- 2-8 Gumbotil, dark-gray, clayey, tenacious; small siliceous pebbles 2-4 Till, leached and oxidized; iron oxide concentrations; pebbles increasingly larger and less altered with depth -------- 1-3 Till, calcareous and oxidized; a few crystalline rock pebbles 2-3 Aftonian: Paleosol, black; erosional remnant -------.-........_..__... 0-1 Nebraskan: Gumbotil, brown-gray to gray, clayey, tenacious; shrinkage cracks prominent when dry; small siliceous pebbles ---- 3 Till, leached and oxidized; concentrations of iron oxides; pebbles increasingly larger at depth ------------------ 2-8 Till, calcareous and unoxidized, blue-gray, compact; fine silty clay matrix containing minute woody fragments ------- 3-4 Silt, sand, and clay of proglacial origin, calcareous ------- 8 Bedrock. After deposition of the oldest till, the Nebraskan, which in the Pleasant Valley section overlies outwash, drainage of the upland surface was poorly organized. After the waning of the ice sheet, during Aftonian in- terglacial time, deep weathering reduced the volume of the till through leaching of its carbonate content, and a clayey gumbotil was produced in the upper part of the deposit where the crystalline rocks had been obliterated and only scattered siliceous insoluble pebbles remained. Meanwhile the master stream of the region, the newly organized Ohio, entrenched its valley into the drift- covered upland surface. Bedrock benches indicative of this stage of landscape dissection were noted by Brand (1934) and Durrell (1961), who did not definitely relate them to the glacial history. Where short tributary streams eroded headward from the deepened major valley into the poorly drained upland, drainage con- ditions were improved. At the Pleasant Valley section, remote from the expanding drainage net, the till of Nebraskan age remained little eroded and poorly drained, so it was deeply weathered in place, as attested by the presence of gumbotil and the remnants of thin humic soil. The succeeding invasion of the Kansan ice sheet into northern Kentucky spread a deposit of till across the up- land; this till was areally less extensive than that of Nebraskan age. In places, drift was deposited in valleys NEBRASKAN GLACIATION cut below the upland during Aftonian time. At the Plea- sant Valley section, Kansan till was deposited on the deeply weathered till of Nebraskan age. The remnant of humic soil indicates that the Nebraskan till was not truncated there by the overriding Kansan ice. Further confirmatory evidence for a sequence of two glacial tills of Nebraskan and Kansan age is provided by an interrupted section one-half mile southeast of the Pleasant Valley section along Pleasant Valley Road. There, 5 feet of deeply weathered till is exposed, and, at a slightly lower altitude about 200 feet farther along the road, 4 feet of calcareous till containing limestone pebbles overlies noncalcareous gumbotil, of which only 1 foot is exposed. Elsewhere, roadcuts in the vicinity are shallow and in general reveal only a deeply weathered surficial silty till, which, on the basis of the Pleasant Valley section, is believed to be of Kansan age. Deeply weathered exposures in the vicinity of Lookout Heights, those adjacent to the Greater Cincinnati Air- port, and those on Pleasant Valley Road lead in- escapably to the conclusion that the uplands of this part of northern Kentucky have been invaded by two ice sheets of pre-Illinoian age. Farther west, only a single deeply weathered drift appears to be present, and its position on the uplands, above the level of a younger drift, leads to the conclusion that it is of Nebraskan age and that the Nebraskan ice sheet was more extensive than that of any succeeding glaciation. The invasion of the relatively undissected upland of southeast Indiana, of southwest and perhaps southeast Ohio (Ray, 1969), and of northern Kentucky by an ice sheet of Nebraskan age is not only of local but of regional significance, for it implies that the ice lobe of the first glaciation in the east-central United States came from the northeast, from the so-called Labradorian dispersal center east of Hudson Bay. Such an ice invasion is presumed to have been penecontem- poraneous with the first ice sheet, the Nebraskan, that invaded the west-central United States from the so-called Keewatin center west of Hudson Bay. That only the area west of Hudson Bay and not that to the east should have been a dispersal center for glacial ice of Nebraskan age is not realistic. Furthermore, the relationship of Nebraskan deposits in the area of the Glaciated Ohio River valley to the regional geomorphic history is ap- parently similar to the relationship of the Nebraskan deposits in northeast Iowa to the regional geomorphic history there (Trowbridge, 1966). DRAINAGE MODIFICATIONS RESULTING FROM THE NEBRASKAN GLACIATION With a few exceptions, most studies concerned with the drainage modifications and development of the pres- ent upper and Glaciated Ohio River valley have 29 followed the basic tenets so well set forth in the classic study by Tight (1903)-that the drainage pattern of to- day evolved largely as the result of glacially induced modifications of preglacial drainage systems. These modifications for the most part resulted from proglacial blockage of drainage channels by the advancing ice sheet; this caused ponding of drainage until the divides between basins were overtopped, and the torrential flow formed new interbasin channels. Elsewhere, preglacial drainage channels may have been overwhelmed by the glacier and permanently destroyed. Most agree that it was the first glacial invasion of the region that most radically modified and integrated the preglacial drainage of the upper Ohio River valley. Although the age of this first glaciation has, until recently, been in doubt, the basic principles marshalled to explain the drainage modifications have remained largely un- changed since the studies by Chamberlin and Leverett (1894a, b). Through recognition of a Nebraskan age for the oldest glaciation in the Ohio River basin, some earlier uncer- tainties have been removed, and a more rational Quater- nary chronology is seemingly possible. However, many unsolved problems remain (Ray, 1969) that can be answered only by detailed field and laboratory studies. Much of the evidence for a detailed regional chronology of the drainage modifications resulting from the glacia- tion of Nebraskan age is fragmentary and obscure, for, except along the Glaciated Ohio River valley, the extent of the Nebraskan ice sheet has not been determined. Inasmuch as the shape and relative rate of advance of the component parts of the ice sheet of Nebraskan age cannot be reconstructed at present, the detailed history of drainage changes occasioned by its advance is in large part speculative. Yet, a working hypothesis is necessary and is presented here to explain those features now observable and to account for the suspected sequence of events. Because the position orf maximum advance of only a small sector of the margin of the ice sheet can be reasonably determined along the Glaciated Ohio River valley, one cannot state dogmatically whether this sec- tor was the terminus of a major advancing ice lobe or merely the lateral margin of a lobe whose main axis presumably lay to the north and west. The writer suspects, however, that the Nebraskan ice sheet in northern Kentucky was the lateral margin of an ice sheet that moved from the northeast into the north- central United States. Furthermore, one cannot assume, for even this small sector of the ice margin, that the position of maximum advancement of the ice was reached simultaneously at all points. Lack of information concerning the rate and position of the advancing ice front at any given time precludes 30 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY determination of the precise sequence of stream blockage, ponding, or the overwhelming of preglacial drainage basins in any but the most general terms. The sequence of events outlined here is presented, therefore, with full knowledge of its speculative qualities and with the hope that future studies may indicate either its basic validity or its fallacies. DRAINAGE MODIFICATIONS ABOVE THE MANCHESTER DIVIDE The drainage modifications that produced the present Ohio River above the Manchester divide have been dis- cussed by many (Chamberlin and Leverett, 1894a, b; Leverett, 1902; Tight, 1903; Happ, 1934; Stout and others, 1943). It is generally believed that in preglacial time along the course of the present Ohio River above the Manchester divide in southern Ohio, there were two major drainage systems separated by a divide at New Martinsville, W. Va. (fig. 5). Regional drainage between New Martinsville and Pittsburgh was to the north through preglacial stream channels that presumably followed the Lake Erie-St. Lawrence lowland to the Atlantic Ocean. Drainage of the present Ohio River valley between the New Martinsville and Manchester divides was, on the other hand, to the west and south to the Gulf of Mexico through the Teays-Mahomet River. The divide at New Martinsville was, therefore, of major regional importance, whereas that at Manchester was less important in that it separated only the drainage basin of the main Teays-Mahomet from that of one of its larger tributaries. It is generally conceded that the ice sheet of Nebraskan age permanently disrupted drainage both to the north and to the west; this resulted in a complex series of stream diversions that in part involved rever- sals in direction of flow. As the ice sheet moved into the lower latitudes from the northeast, north-flowing streams draining through the Lake Erie-St. Lawrence lowland were the first to be blocked and impounded. As the ice advanced and the impounding continued, water levels increased in the drainage basins, and widespread fingerlike lakes formed. These proglacial lakes may have been interconnected by the overtopping of many minor cols between tributary streams. The impounded normal drainage, greatly augmented by melt-water torrents, eventually rose to overtop and breach the lowest col along the divide at New Martinsville, which separated the headwaters of the impounded north-flowing rivers from the west-flowing Teays-Mahomet drainage. Even- tually, the divide was thoroughly breached and per- manently destroyed. As a result, the preglacial northward flow of streams above the divide was reversed to the south, and the first major transforma- tion in the formation of the Ohio River basin of today was accomplished. The precise time at which the Manchester divide was overtopped relative to the position of the advancing ice sheet of Nebraskan age is conjectural. The main stem of the Teays-Mahomet drainage system must have been overwhelmed at some point by the glacier in order to be impounded above the Manchester divide (fig. 5) and eventually overtop the divide. Whether the waters of the north-flowing Cincinnati River, tributary to the Teays- Mahomet, were impounded by the advancing ice sheet in southwest Ohio before or after the breaching of the Manchester divide is not known. If the waters of the Manchester River, augmented by the torrential waters flowing across the breached Manchester divide, had joined those of the Cincinnati River, and if this com- bined Manchester-Cincinnati River had existed for any extended period of time as a major tributary to the Teays-Mahomet (fig. 5), one would suspect that a valley eroded in the area of outcrop of Silurian formations in the vicinity of Dayton, Ohio, would be a conspicuous bedrock feature. Because no such valley is known, the torrents flowing to the north to join the Teays-Mahomet drainage probably did not exist for long and the ice sheet of Nebraskan age must have overwhelmed the lower course of the Cincinnati River almost simultaneously with the blocking of the main Teays drainage, or shortly thereafter. Therefore, not long after the breaching of the Manchester divide, all drainage to the main Teays- Mahomet River was impounded in high-level digitate lakes in the preglacial basins of the Cincinnati River and its tributaries, such as the Manchester, Licking, and Kentucky Rivers. On the basis of present information, one can accept only the belief that when the advance of the Nebraskan ice sheet blocked the main stem of the Teays-Mahomet River, presumably in central Ohio, its drainage was im- pounded, and the ice-dammed river rose to overtop and breach the Manchester divide. If, however, the Manchester divide was later overridden by the Nebraskan ice sheet at the time of its maximum ad- vance, a possibility suggested by Ray (1969), the divide was for a brief time inoperable, and a more complex history of drainage modifications is required. Presumably, whatever drainage diversions may have been caused by the possible overriding of the Manchester divide, the resulting channelways were not permanently established. After the waning of this possi- ble ice advance, the channel across the Manchester di- vide was reoccupied, and the drainage reestablished to the west has continued to the present. Later dissection of the preglacial upland surface, together with the deep weathering and erosion of surficial deposits, may have NEBRASKAN GLACIATION 31 so obscured the sequence of events that the history of drainage modifications will be difficult, perhaps im- possible, to verify completely. Whatever the sequence of events, the writer suggests that as a result of the first glaciation, the Nebraskan, drainage above the Manchester divide was initially integrated into a single basin and was later forced to breach the divide permanently and flow west along the preglacial Manchester River. Some have suggested that not all drainage diversions above the Manchester divide resulted from glacial dis- ruption of the preglacial drainage net. Rhodehame! and Carlston (1963) suggested that the Teays River valley in West Virginia "*** was abandoned in late Tertiary or early Pleistocene time by normal stream capture processes***" (p. 251). They stressed the deeply weathered alluvium on the bedrock valley floor and proposed for it a late Tertiary (?) or early Quaternary age, inasmuch as it consists largely of siliceous insoluble materials derived from within the preglacial drainage basin. They implied that this alluvium is essentially preglacial bedload. Furthermore, they noted (p. 260-261) an illuvial "pan" at or near the base of the alluvium in places and interpreted it as a weathering product that has "migrated down" through the coarse siliceous in- soluble materials. The writer suggests that the materials derived from within the basin are the ancient bedload whose transportation downstream was halted when the river became ice dammed and its drainage im- pounded, and that into the impounded waters, fine- grained sediments, largely silt and clay, probably calcareous, were introduced by proglacial melt waters. When the Nebraskan ice sheet waned and the drainage had been rearranged, alluvium within the valley was subjected to subaerial weathering and erosion, and a mature soil profile formed during Aftonian interglacial time. When the valley was again flooded by impounded waters, presumably as a result of the Kansan ice sheet advance, the deeply weathered alluvium was mantled by a younger lacustrine deposit, the Minford Silt of Stout and Schaaf (1931). In summary, the interpretations briefly presented here follow in large part the earlier beliefs that the in- tegration of drainage above the Manchester divide and the consequent diversion of torrential drainage across the divide to the west along the course of the preglacial Manchester River resulted from an invasion of the preglacial drainage basins by an ice sheet of Nebraskan age. Details, especially the timing of drainage modifications during the ice advance, are obscure. Furthermore, it has been suggested that during the maximum advance of the ice sheet, the Manchester divide itself may have been briefly ice covered and the resulting drainage complicated in ways not yet un- derstood. DRAINAGE DEVELOPMENT BETWEEN THE MANCHESTER DIVIDE AND THE LOUISVILLE AREA When the north-flowing Cincinnati River and the main Teays-Mahomet River had been impounded by the advancing Nebraskan ice sheet, melt waters issuing from the ice sheet from northwest Pennsylvania to southeast Indiana, together with drainage from the un- glaciated parts of the drainage basins, were gathered into a series of proglacial lakes whose height was regulated by the altitude of the lips of the cols along the interbasin divides. When cols between the basins were breached, the impounded torrents, flowing from one basin to a lower basin, quickly eroded the divides so lake levels were maintained only temporarily at their max- imum heights. The brevity of sustained lake levels may explain the lack of evidence for abandoned shorelines and beaches at high levels in northern Kentucky. At the time of the greatest extent of the Nebraskan ice sheet, a proglacial lake may have existed between the Manchester and Madison divides, if only temporarily, as a series of connected lakes occupying the impounded basins of the major stream valleys and their tributaries. Presumably the impounded lake waters rose to the height of a col in the Madison divide, possibly somewhat - below an altitude of 850 feet, and overtopping the col allowed escape to the west through the Salt River drainage to the Mississippi embayment-the drainageway now occupied by the Ohio River. Thus, for the first time, Salt River was a drainageway of major regional importance, serving as a sluiceway for glacial melt water and for drainage from a greatly expanded basin that had belonged in part to the preglacial Teays- Mahomet River system. As the ice sheet continued to advance, the confluence of the stream south of Hamilton, Ohio, was overridden, and the direct connection between drainage from the east and the west was blocked (fig. 6). To the east the ponded drainage of the Manchester and Licking Rivers rose until, by a series of diversions in northern Ken- tucky from one impounded proglacial basin to another, drainage presumably reached the ponded Kentucky River basin, thereby gaining access to the westward drainage across the Madison divide. The drainageways connecting these basins have not been determined in the field, although many stream-modified high-level cols and channels containing fluviatile deposits are well known on the uplands (Leverett, 1902, 1929; Durrell, 1961). These now-abandoned drainageways are intermediate in altitude between the preglacial bedrock valley bottoms of Parker (Pliocene) age and the broad rolling uplands of the Lexington plain. High-level channels with deposits of sand, gravel, and laminated clay, not to be confused 32 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY with deposits of the Irvine Formation of preglacial age, are common in northern Kentucky immediately beyond the limits of glaciation (Durrell, 1961). In many areas, subsequent erosion and weathering may have modified or destroyed so much of the evidence that the complete and complex picture of the maze of interbasin channels and the sequence of drainage changes may never be precisely determined. During final advance of the ice sheet along a broad front in the Cincinnati to Louisville area (pl. 1), the glacier reached its position of maximum extension in northern Kentucky. Here it crossed and obliterated the newly organized reversed drainage to the west along the preglacial Kentucky River valley and its tributary Eagle Creek valley, the newly breached Madison divide, and the drainage channel west from the Madison divide along the north branch of Salt River. Although this posi- tion is important in the drainage history, it was not long maintained and may have been related to a local ice surge. Because the extended glacier was too feeble to con- tinue its forward movement, it is presumed to have been thin, possibly fluctuating locally, highly crenulated along the margin, and rapidly melting. Little coarse or crystalline debris appears to have been carried by the frontal ice in its terminal position, so melt water, laden largely with sand, silt, and clay, either was discharged along the ice front into dammed stream valleys and shallow proglacial upland lakes or was thinly spread across the upland surface as widespread outwash plains, as in northern Boone and Kenton Counties, Ky. (Luft, 1969; Swadley, 19692, b). As soon as the advancing ice sheet overwhelmed the newly organized channel between the Cincinnati and Louisville regions and the breached Madison divide, drainage was totally disrupted, and a new bypass channel became an immediate necessity. As a result, two independent west-draining channels formed along the ice margin for temporary relief of the blocked drainage. The first, east of the Madison divide, followed in general the present lower course of Eagle Creek, now tributary to the Kentucky River (fig. 3). The second, west of the Madison divide, followed a course similar to that of the present Harrods Creek, now tributary to the Ohio River immediately above Louisville, Ky. (fig. 3). Each bypass channel temporarily directed the torrential drainage to the west along routes that converged at the head of the preglacial Salt River gorge through the Knobstone-Muldraugh Hill escarpment. From there, drainage followed the preglacial channel of Salt River to the Mississippi embayment. The bypass course east of the Madison divide has long attracted attention because of the sharp, right-angle bend in the course of Eagle Creek about 4 miles east of Glencoe, Ky. (Elliston and Glencoe quads., Kentucky). At this bend, the north-flowing Eagle Creek, following in general its preglacial channel, turns abruptly southwest to follow a course that is only a short distance south of and more or less parallel to the margin of the drift of Nebraskan age (pl. 1). This striking change in direction of flow, noted by Leverett (1902), Tight (1903), Fowke (1983), Jillson (1949), and Durrell (1961), has generally been attributed to stream capture through piracy. Recent detailed mapping has revealed, through relict fluviatile deposits, a preglacial high-level channel leading from the presumed elbow of capture to the northeast (W C Swadley, oral commun., 1969). This con- firms the belief that the preglacial Eagle Creek was tributary to the northeast-flowing Kentucky River that was, in turn, tributary to the Teays-Mahomet River through the Cincinnati (north-flowing Hamilton) River (figs. 8 and 10). Although field data are few, the spectacular diversion of Eagle Creek drainage is, on the basis of the present study, believed to be the direct result of glacial modifications and not of stream capture through piracy. When maximum advance of the first ice sheet caused disruption of the newly formed drainageway that had supplanted the preglacial Teays-Mahomet River, a bypass channel was formed that skirted the ice margin. West of the ponded Licking River basin were the ponded Kentucky River and Eagle Creek basins. Presumably drainage from the east followed high-level channels into the Licking River basin and thence through upland channels not yet identified, into the ponded Eagle Creek basin. From the Eagle Creek basin to the ponded Ken- tucky River basin farther west, the torrents followed an integrated ice-margin channelway between small proglacial lakes fringing the ice margin. The southwest course of the present Eagle Creek appears to follow, roughly, this high-level bypass channel (pl. 1). The general character and extent of the proglacial lakes and high-level drainageways may eventually be more precisely defined through detailed mapping o the sur- icial deposits. Drainage following the ice-margin channelway from the east reached the ponded preglacial Kentucky River basin in the vicinity of Worthville (Worthville quad., Kentucky). Because escape of the ponded waters to the west, across the Madison divide, was blocked by glacial ice, another escape route from the ponded Kentucky River basin had to be found. The writer suggests, as a working hypothesis, that the impounded waters rose to overtop briefly a low divide or divides between the Ken- tucky and Salt River basins. The points of overtopping are not known but may be the channels described by Leverett (1929) as being mostly below 800 feet in altitude and lying between valleys now tributary to the Kentucky River and those tributary to the Salt River. AFTONIAN INTERGLACIAL TIME 38 He (1929, p. 8) noted that "these channels appear to be somewhat later than the Irvine formation, yet they date from a time prior to the main channeling of the Ken- tucky and Salt River." Inasmuch as the load carried across these divides from the ponded river basin was at a minimum, the divides may have been so little modified by erosion that today they are relatively inconspicuous terrain features. West of the Madison divide, the channel now occupied by the Ohio River had likewise been overwhelmed and obliterated as a drainageway at maximum ice extent (pl. 1). Unlike the extensive drainage basin east of the Madison divide, drainage to the west consisted essential- ly of melt waters locally derived from the melting ice. Like the sector to the east, however, drainage appears to have been largely confined at first to small proglacial lakes that were later integrated into an ice-marginal stream flowing west along a channelway now represented by Harrods Creek (pl. 1; Ray, 1966). Because of the glacial outwash locally available to the ice-margin stream, the channelway was rapidly eroded and became a permanent terrain feature similar to the glacially formed lower course of Eagle Creek. At the maximum advance of the ice sheet of Nebraskan age, melt water and local drainage from the entire area from northwest Pennsylvania to the vicinity of Louisville was funnelled to the Mississippi embay- ment and thence to the Gulf of Mexico through the preglacial Salt River gorge in the Knobstone-Muldraugh Hill escarpment. Volume of this drainage was, because of the melt water, much greater than the volume of flow of the present Ohio River. AFTONIAN INTERGLACIAL TIME There is little tangible evidence in the Ohio River valley region to enable a satisfactory reconstruction of the history of the first interglacial stage, the Aftonian. Evidence consists of the mature profile of weathering developed on Nebraskan drift and preserved beneath Kansan drift, and of stream valleys eroded into the drift-covered uplands after deposition of the Nebraskan drift and before deposition of the Kansan drift (Leighton and Ray, 1965; Ray, 1966). Boundaries for Aftonian interglacial time are transgressive, indefinite, and, in the Ohio River valley region, indeterminate (Ray and Karlstrom, 1968). However, the advanced profiles of weathering and the amount of terrain dissection attributed to Aftonian time indicate that the Aftonian was much longer than was formerly believed. In northeast Iowa, for example, where, as in the Ohio River valley, both Nebraskan and Kansan drifts are present, Aftonian time was a period of weathering and stream dissection of the upland on which till of Nebraskan age is present. Trowbridge (1966) was skeptical, because of the time requirements, that so much stream erosion could have been ac- complished during Aftonian time. Willman and Frye (1969), however, supported Trow bridge's conclusion that the upland was dissected during Aftonian time and the corollary that the Nebraskan drift predated the valley cutting and the Kansan drift postdated it, a geologic history similar to that along the Ohio valley. Theoretically, the ice sheet of Nebraskan age, after at- taining its position of maximum expansion, began to wane, presumably as the result of a general climatic amelioration. The long-continued dissipation of the ice sheet was probably not uniform; rather, there were long- and short-term regional reversals as well as local fluc- tuations along the melting ice margin. Whether the Nebraskan ice sheet completely disappeared during Af- tonian time or lingered on in its nuclear region cannot be answered. Neither is it possible, on the basis of available evidence, to estimate the length of nonglacial time or to determine the time required for regeneration of the later Kansan ice sheet and for its movement to its posi- tion of maximum advancement. Stratigraphically, Afto- nian time is observable only as an unconformity where weathered Nebraskan drift is overlain by Kansan drift, for no deposits referable to Aftonian time have been recognized in the Ohio River valley region. On the undissected uplands where Nebraskan drift is overlain by Kansan drift, weathering started as soon as the Nebraskan drift was exposed by dissipation of the overriding ice and continued until the deposits were again covered by the advancing younger ice sheet of Kansan age. Because of poor drainage on the uplands, long-continued weathering resulted in a typical gum- botil profile characterized by a surficial horizon of heavy brownish-gray tenaceous clayey thoroughly decomposed till in which only the most resistant siliceous insoluble materials remain as randomly scattered pebbles. Such deeply weathered material is well represented in the Pleasant Valley section (Leighton and Ray, 1965), where truncation of the profile was at a minimum. Elsewhere, the overriding Kansan ice sheet has commonly trun- cated the profiles. Gooding (1966) and Murray (1955) reported profiles of weathering that are here assigned to the Aftonian time. Gooding (1966) reported 4 feet of noncalcareous clayey mottled yellowish-brown and gray till at the Osgood sec- tion, and Murray (1955) reported about 7 feet of dark- reddish- and greenish-brown compact clayey till con- taining abundant siliceous pebbles. Both tills are here interpreted to be of Nebraskan age, and the weathering profiles developed on them are, therefore, of Aftonian age, for the overlying younger tills are interpreted to be of Kansan age. In the Dabney section (p. 25) the profile has been so thoroughly truncated that almost none of 34 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY the profile of weathering remains, yet the dark-brown compact crumbly calcareous till containing much chert and crystalline rock has the general appearance of a lower horizon of a weathering profile that had been produced in Aftonian time and later eroded and covered by Kansan drift. Where, as in the Lookout Heights and Airport sections, the compact clayey gumbolike profiles of weathering have been modified because of later im- provements in drainage conditions, silttils have resulted. Silttil profiles are common in all but the un- dissected upland areas. Dissection of the uplands by stream erosion in Afto- nian time is best illustrated in northern Kentucky where both Nebraskan and Kansan tills are present (pl. 1). Along the outer margin of the Kansan ice sheet, out- wash and till were deposited in valleys intermediate in altitude between the upland surface and the bottoms of the present stream valleys. The best example of a drift- filled valley is near an altitude of 500 feet along the north wall of Riddles Run (Rising Sun quad., Kentucky- Indiana). There, a thick till section was revealed in a new roadcut in 1960. About 20 feet of compact, oxidized, clayey, and highly calcareous till was exposed that con- tained fragments of local limestone and pebbles and cobbles of crystalline rock as much as 18 inches in max- imum diameter. Fractures extending through this com- pact calcareous till were marked by limonite staining. Above the till, only 6 to 8 feet of leached till was preserved, indicating that erosion had almost kept pace with leaching along the steeply sloping valley wall. At the base of the leached till as well as in the lower un- leached till, secondary calcareous concretions were abundant, and in places, larger cobbles were in part coated with secondary calcium carbonate. No "ghosts" or deeply rotted erystalline cobbles were noted. About a mile up the valley, an exposure of about 20 feet of leached silty fine sand was interpreted to be glacial out- wash of Kansan age. The presence of deep valleys filled with drift of Kan- san age was confirmed during the winter of 1968-69, when a landslide revealed a bedrock channel along the south wall of Gunpowder Creek about 2 miles northeast of the Riddles Run outcrop of Kansan till. The silty sand filling of the channel was well exposed, and the lower part of the deposit contained large and abundant calcareous nodules that indicated a long period of weathering and a bountiful source of calcite. Because the ridge surface up to an approximate altitude of 750 feet is sandy, there is an estimated thickness of 200 feet, more or less, of Kansan outwash in the valley to provide the source for the secondary calcium carbonate nodules. West of the Madison divide the newly organized Ohio River entrenched itself during Aftonian time far below the adjacent uplands, as indicated by an outcrop of Kan- san till (Ray, 1957) on a bedrock bench along the south wall of the Ohio River valley at the mouth of Phillips Branch (Bethlehem quad., Indiana-Kentucky). The bedrock bench is about 50 feet above the pool stage of the Ohio River and more than 300 feet below the adja- cent upland that is mantled by deeply weathered Nebraskan drift. The bedrock bench is interpreted to be a remnant of a terrace formed by river erosion during Aftonian time, before the Kansan ice advance. Such deep trenching by the river was possibly the result of static rejuvenation because of the increased volume of flow produced by drainage-basin expansion during Nebraskan time. No other remnants of this terrace have been found along the Glaciated Ohio River valley. No regional uplift is believed necessary to explain the amount of erosion accomplished during Aftonian time, for erosion was vastly aided along the major streams by melt-water torrents and debris transported during the waning of the Nebraskan ice sheet and by melt-water flow during the advance of the Kansan ice sheet. Doubtless, flow was also increased by the reversal of climatic conditions-from the warm dry interglacial time to the cool wet glacial climate. No evidence of crustal uplift or depression resulting from glaciation has been found in the Glaciated Ohio River valley region. After the Nebraskan ice sheet had disappeared from the Glaciated Ohio River valley, the main stem of the river is believed to have followed once again the preglacial channel of the Manchester River from the Manchester divide to the vicinity of Hamilton, Ohio, where it turned southwest to follow the south-flowing course of the Cincinnati (Hamilton) and Kentucky Rivers to the Madison divide, and thence west along the course of the preglacial northern branch of the Salt River (fig. 9)-a course in general similar to that of to- day except in the Cincinnati region. The new bypass channels formed during the maximum advance of the Nebraskan ice sheet were presumably of too short a duration to have become permanently established. KANSAN GLACIATION The second ice sheet to invade the Glaciated Ohio River valley region from the northeast was of Kansan age. In many respects it appears to have been similar to, though somewhat less extensive than, the ice sheet of Nebraskan age. Deposits of both glaciations lack sur- ficial topographic expression, and postdepositional weathering has been so great that the drifts are in- distinguishable in sections in which only a single till is exposed. The lack of topographic expression may be the result of original drift deposition, the result of long- continued postdepositional weathering and erosion, or, most likely, a combination of both. Because no precise means has been devised for field differentiation between the Nebraskan and Kansan drifts in shallow expsosures KANSAN GLACIATION 85 of a single drift, the mapped boundaries (pl. 1) are of necessity generalized and may require revision as more detailed information is gathered. Flint (1957) stated that the Kansan drift, like the Nebraskan, was wholly overlapped by the next younger drift, the Illinoian. In the region of the Glaciated Ohio River valley, however, this relationship is not valid, for, according to the interpretations presented here, the Kansan ice sheet was much more widespread than the Illinoian ice sheet (pl. 1). At its position of maximum advancement, the Kansan ice sheet was slightly less extensive than the earlier, Nebraskan ice sheet except in the south part of the Scottsburg lowland, along the base of the Knobstone- Muldraugh Hill escarpment. There, the marginal part of the Kansan ice sheet was not sufficiently vigorous to override the escarpment, as did the Nebraskan ice sheet, and was deflected to the south, overriding the Nebraskan drift, possibly as far as the Ohio River. Melt- water torrents coursing through the Ohio River valley may have halted, in this area, the final advance of the deflected ice sheet to the south. On the uplands of northern Kentucky, south and southwest of Cincinnati, the forward movement of the Kansan ice sheet was uninhibited, for at that time the deep gorgelike valley now occupied by the Ohio River between the mouths of the Great and Little Miami Rivers did not exist. Furthermore, the valley walls along the ancient channel looping to the north around Cincin- nati to the vicinity of Hamilton, Ohio, were not high enough to halt the vigorous forward movement of the advancing ice sheet. To the southwest, no evidence has been found that the Kansan ice sheet reached the present Ohio River valley between Rising Sun and the Madison area (pl. 1). It is suggested here that a broad strip of upland adjacent to and back from the Ohio River valley in southeast In- diana was not glaciated in Kansan time. On this strip of upland, glaciated only in Nebraskan time and partly dis- sected in pre-Kansan (Aftonian) time, no exposures have been observed in which there is more than a single deep- ly weathered glacial till, believed to be of Nebraskan age. So highly modified is this till through weathering that commonly surficial deposits on the upland rem- nants are not recognized as deeply weathered glacial till (Bushnell, 19587). The coarse till and surficial boulders associated with the Kansan till in northern Kentucky, south and southwest of Cincinnati, are not present in this area. The shallow exposures are largely of silt con- taining scattered siliceous insoluble materials. Where postdepositional erosion has left larger remnants of the original flat upland surface and the weathered till is poorly drained, the till tends to be heavy, clayey, and tenacious a few inches below the surface. Northwest of the upland strip of exposed Nebraskan drift, in the area of surficial Kansan drift (pl. 1), a few sections indicate two distinct glacial tills, and seattered boulders are locally present. Sections of thick, surficial till are in places calcareous at depths generally greater than 10 feet. In those sections described by Murray (1955) at the Muscatatuck State School (Spillway section) and at the Scott County Stone Co. quarry, two glacial drifts are ex- posed that he interpreted to be of Illinoian and Kansan age. This interpretation is herein challenged, and the older drift at the Spillway section is assigned a Nebraskan age (p. 24). The younger surficial drift, first referred to as Illinoian by Leverett, is here referred to a Kansan age on the basis of its deep profile of weather- ing, for it is leached to a depth of 12 feet below a surficial 5 feet of clayey gumbolike weathered till. At the Scott County Stone Co. quarry, the upper till is likewise reported in part clayey and is leached to a depth of 14 feet. This leaching is greater than that on Illinoian till elsewhere and is characteristic of the deposits that have been referred to a Kansan age in southwest Ohio by Durrell (1961). A truncated and surficially modified exposure in a pit on the uplands at Madison, Ind. (south of State Route 107, NE1/4 SE1/4 see. 21, T. 4 N., R. 10 E., Clifty Falls quad., Indiana), is leached to a depth of approximately 10 feet. Many erratics, 2 to 3 feet or more in diameter, are scattered across the pit floor. These erratics are seemingly characteristic of the Kansan drift. Abundant wood fragments were reported to have been recovered many years ago from deep sewer excavations in the poorly drained till on the flat uplands in the newer residential area of Madison, Ind., not far from the pit containing the scattered glacial boulders (G. T. Wickwire, oral commun., 1964). No attempt was made to determine the type of wood or its age by carbon-14 methods, for presumably the wood was too old. One is . reminded, however, of the wood in the lower part of the upper till in the Scott Stone Co. quarry (p. 25). In both places the wood-bearing till, formerly assigned an Illinoian age, is here referred to a Kansan age. Immediately west of Scottsburg, Ind., the best till see- tion of southeast Indiana was studied in the field at the time it was fresh (1966). A succession of two deeply weathered deposits was exposed in an artificial cut in a lowland area. Weathering of the younger surficial till is so advanced that the till is assigned a Kansan age, and the underlying till is therefore assigned a Nebraskan age. West and south of the Madison area, on the Muscatatuck regional slope, the Kansan ice sheet is believed to have reached the present Ohio River valley and to have crossed it locally (Ray, 1957, 1965b, 1966). 36 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY Scottsburg section [West side of artificially straightened and deepened section of Honey Creek in NW1/4 see. 19, T. 3 N., R. 7 E., 250 ft north of Indiana State Highway 56 and 400 ft west of cloverleaf in- tersection with Interstate 65, Scottsburg quad., Indiana] Thickness Wisconsin (Peorian) loess: (feet) 8-10 in. light-gray noncalcareous silt, underlain by buff- yellow somewhat clayey silt mottled with gray; crumbles to small flaky peds; iron oxide pellets ----------------. 8.5 Kansan drift: Heavy compact yellow noncalcareous silty clay with pronounced surficial drying cracks; some gray mottling and veining; small pebbles of siliceous insoluble materials scattered at random throughout. Pronounced break in slope at top of zone on eroded surface ---------------. Compact buff-yellow noncalcareous clayey silt; surficial dry- ing cracks not as prominent as in overlying zone; gray veining and many iron oxide pellets ---------------... Similar to overlying zone but containing many secondary calcite pellets, irregular sheets, and masses; pellets of iron oxides increase with depth; a few small siliceous insoluble pebbles scattered at random but no crystalline-rock com- ponents 8 Nebraskan drift: Red-brown to gray noncalcareous clayey surficial layer con- taining a few secondary calcareous nodule contaminants from overlying layer; prominent drying cracks; black staining along fractures. The few crystalline rocks in this layer erumble readily on exposure 2+ Pebbly calcareous till, buff at surface; grades downward to hard compact blue-gray till at depth. Limonite staining along fractures; a few lenses of brown sand. Crystalline components to 2 ft in diameter; rotten in upper part but fresh at depth. Limestone cobbles and pebbles are striated, soled. and faceted -- -- -s. >- Covered. 3-4 12+ The frontal margin of the enfeebled and extended ice sheet may have been halted, except locally and for brief periods, by the melt-water torrents carried by the river, and the Ohio River valley may essentially mark the maximum position of advancement attained by the ice sheet of Kansan age between the Madison and Louisville areas. Where the ice sheet briefly crossed the valley, it deposited drift in subsummit positions within the mouths of small tributary valleys cut below the upland surface during Aftonian time. At and downstream from the mouth of Phillips Branch (Bethlehem quad., Indiana-Kentucky), Kansan drift is present on a bedrock bench on the south side of the Ohio River valley (Ray, 1957). This elongate morainelike mass of deeply weathered till was described but not explained by Fowke (1933), who inferred that it was possibly a river terrace. When first examined in 1956, the exposure along a road- cut adjacent to Phillips Branch was fresh, and an ideal profile of weathering was exposed that extended from calcareous till resting on bedrock to a surficial silt con- taining scattered siliceous insoluble pebbles mantled by a thin layer of Peorian loess. The bedrock terrace on which the till rests is now interpreted to be of Aftonian age. No evidence has been found to suggest that this part, of the river valley was ice dammed for any extended' period of time above the Phillips Branch, yet the river may have been temporarily ponded so that melt waters were forced to escape once again through the Harrods Creek valley, as postulated for Nebraskan time. Com- parison of the weathered Kansan till at Phillips Branch with the more deeply weathered silttil of Nebraskan age on the adjacent uplands, especially on nearby Covington Ridge, indicates the long time interval and amount of weathering possible during the Aftonian interglacial time. Evidence for Kansan drift on the uplands of northern Kentucky south and southwest of Cincinnati, Ohio, has been discussed with the evidence for Nebraskan drift on the uplands (Leighton and Ray, 1965; Ray, 1965b, c). There, the younger, surficial, moderately to well- drained Kansan drift is commonly a silttil in which siliceous insoluble materials, largely chert pebbles, are scattered at random. Only in the flat poorly drained areas is the weathered Kansan drift clayey and gum- bolike. Near the present Ohio River valley, shallow ex- posures of silttil of Kansan age may be confused with a thin overlying blanket of weathered noncalcareous loess of Peorian (Wisconsin) age. The two can be readily separated, however, on the basis of the lack of scattered insoluble materials in the loess. Farther from the river valley today, where loess is thin or absent, cobbles of crystalline rock and quartzite of Kansan age are thinly scattered across broad areas of uplands, but, as in southeast Indiana, they have been avidly collected and largely removed as exotics for ornamental purposes. These cobbles, present only on the surface of the Kansan drift, may be genetically related to that drift. Along the south and southwest terminus of the Kan- san drift on the uplands of northern Kentucky, drift is present in small valleys cut below the upland surface in Aftonian time by headward-eroding tributaries of the newly established Ohio River. Both glacial till and out- wash from the Kansan ice sheet were deposited in these valleys, as observed along Riddles Run and Gunpowder Creek (p. 34). The best known valley fill, here assigned a Kansan age, is the so-called "Middle Creek con- glomerate" composed of cemented sand, gravel, and cobbles of limestone and a few crystalline rocks and quartzite. This conglomerate occupies a broad channelway cut below the general upland surface between Gunpowder and Woolper Creeks (Rising Sun quad., Kentucky-Indiana, and Lawrenceburg quad., Kentucky-Indiana-Ohio) and is widespread in the vicini- ty of Commissary Corner and the valley of Middle Creek. The area that includes the conglomerate is now deeply eroded, especially by Middle Creek, to narrow valleys with rugged, precipitous walls 60 feet or more KANSAN GLACIATION 37 high. The "Middle Creek conglomerate" has been com- pared and correlated with the nearby "Split Rock con- glomerate" that crops out along and back from the pre- sent Ohio River adjacent to the mouth of Woolper Creek, about 4 miles west and north of Commissary Corner. These conglomerates have been an unsolved geologic problem since they were first described by Dr. John Locke in the Cincinnati Gazette for September 23, 1845. Sutton (1877, 1879), after describing the two con- glomerates, reached the conclusion that, despite their similarities, they were not of the same age. The "Split Rock conglomerate," about 300 feet lower than the "Mid- dle Creek conglomerate," he interpreted to be the younger: "The one [Middle Creek conglomerate] dating back to a period prior to the formation of our valleys, the other after the river [Ohio] had cut down its channel 450 feet***" (Sutton, 1879, p. 111). In 1902 and again in 1929, Leverett (1929, p. 55) refuted this interpretation and stated, From the wide difference of level at which these conglomerates occur, Sutton drew the inference that they are widely different in age, it be- ing assumed that they are remnants of river terraces. They appear, however, to be better classed as exceptionally stony till, rather than an assorted stream deposit. The wide difference in altitude may thus signify nothing as to time relation. Leverett's conclusion (1929, p. 56) was evasive-"These conglomerates*** are probably a result of the bridging of the Ohio Valley by the ice sheet, but just how they were produced is a matter of speculation and variety of opinion." Durrell (1956), essentially following Sutton, reached the conclusion that the "Split Rock con- glomerate" was of Illinoian age and that the "morainelike deposits on the upland near Commissary Corners, Kentucky, and the 'Middle Creek conglomerate' just to the south are pre-Illinoian terminal deposits." One can reasonably infer that conditions similar to those in northern Kentucky were present in southeast Indiana along the margin of the Kansan ice sheet between Rising Sun and Madison and that deposits of Kansan age might be found in valleys cut below the Nebraskan drift-mantled upland surface in Aftonian time. No such deposits, however, have been located (Rich, 1956). Erraties found on valley walls and in creek beds are like those of northern Kentucky and are believed to have been derived secondarily by erosion of the Nebraskan drift on the uplands. The west boundary of the surficial Kansan drift in southeast Indiana is poorly defined and in part masked by the overlapping deposits of younger glaciations (pl. 1). From the Ohio River north to the valley of the Muscatatuck, the outer terminus of the ice sheet and deposits of Kansan age appear to follow roughly the base of the Knobstone-Muldraugh Hill escarpment. In places, proglacial lakes appear to have been impounded between the irregular ice margin and the irregular base of the escarpment. Remnants of deeply weathered lacustrine deposits indicate the presence of such lakes. Where the Muscatatuck River and the East Fork of White River combine to cut through the escarpment on their course to the west, evidence of Kansan drift has been removed by post-Kansan stream erosion and alluviation. However, a boundary separating the Kan- san till on the east from the overlapping till of Illinoian age on the west has been drawn along the base of the massive Chestnut Ridge terminal moraine (Cox, 1879; Leverett, 1902, 1929) of Illinoian age and along its con- tinuation to the southwest, the Tampico Ridge moraine (pl. 1). This boundary has been arbitrarily continued north from the Chestnut Ridge moraine, across the broad outwash deposits of the East Fork of White River, to the point in northwest Jennings County where drift of the youngest glaciation, the Wisconsin, overlaps all older deposits. The extent of the pre-Illinoian glacial drifts west of this boundary is not known, but a small area of surficial till has been mapped as Kansan by Wayne (1958). Age determinations of pre-Wisconsin glacial drift from northwest Jennings County to the valley of the Great Miami River have proved difficult for many reasons, one of the most important being the paucity of deep outcrops on the upland flats. Where outcrops are present on slopes immediately below the summit levels, they are generally incomplete and truncated by erosion. The problem posed was whether a strip of glacial drift of Illinoian age intervenes between the outer margin of the drift of Wisconsin age and the widespread drift of Kan- san age in southeast Indiana (pl. 1). At first, on the basis of field study, the writer believed that the drift of Illinoian age appeared from beneath the Wisconsin drift border midway across Decatur County and that, from that point to the valley of the Great Miami River, Illinoian drift was present as a surficial deposit. Attempts, however, to locate the southern boundary of this postulated strip of Illinoian drift have proved un- successful in the field, and the belief in an intervening strip of Illinoian drift has been abandoned, despite the fact that there are marked differences in the terrain and seemingly in the deposits of pre-Wisconsin drift in Franklin and in adjacent Ripley and Dearborn Counties to the south. It first appeared to the writer that the marked change in the landscape north and south of the drainage divide between the basin of the Whitewater River and that of the tributaries to the more distant Ohio River (fig. 3) in- dicated a possible difference in the age of the drifts and the geologic history on either side of the divide. North of the broad flat-topped drainage divide, the streams are more steeply graded, and the terrain has greater relief 38 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY as the result of headward erosion by tributaries of the nearby Whitewater River. Steep-walled valleys, in places cut into bedrock, deeply dissect the drift-mantled upland surface. South of the divide, the relief is less, the valleys are generally less steep walled, and the drift- mantled upland is less dissected. The different types of terrain are well shown on the Metamora, Batesville, and Pierceville quadranges, Indiana. Gooding (1957, 1963), following the earlier studies of Leverett and others, recognized only tills of Illinoian and Wisconsin age in the drainage basin of the Whitewater River. Thus, he was led to the conclusion that only drift of Illinoian age is present on the dissected uplands south of the boundary of the Wisconsin drift in southeast In- diana. If this is true, then, as he suggested (1957, p. 28), the valley of the West Fork of the Whitewater River was probably cut during Sangamon interglacial time, that is, in post-Illinoian-pre-Wisconsin time. This conclusion is not in harmony with the generally held belief that major streams were cut to their greatest depth during the "Deep Stage" before the invasion of the Illinoian ice sheet. A pre-Illinoian (Yarmouth) age for "Deep Stage" erosion is supported by the presence of drift of un- doubted Illinoian age within the bedrock valleys of the major streams, such as the Ohio and Great Miami Rivers. Examination of the relationship of the bedrock terrain and the glacial deposits indicates that south of the border of the Wisconsin drift and east of Decatur Coun- ty in southeast Indiana, the pre-Wisconsin drift in the drainage basins of the Whitewater River and of the tributaries to the Ohio River is confined to the upland flats, remnants of the preglacial Dearborn upland, and to the relatively shallow valleys cut into the upland in post-Nebraskan, Aftonian time. If the present major valleys, deeply cut into bedrock and later alluviated, are the result of "Deep Stage" erosion, commonly believed to be of pre-Illinoian (Yarmouth) age, one would expect that drift of Illinoian age would be present in the deep bedrock valleys. No drift is present; therefore, if one accepts a Yarmouth age for "Deep Stage" erosion, one is led to the conclusion that the oldest drift in this area was deposited in pre-Yarmouth time, before formation of the deep valleys, and is thus of pre-Illinoian, presumably Kansan, age, as shown on plate 1, and that in this part of southeast Indiana, no drift of Illinoian age is present between the southern limit of the drift of Wisconsin age and the Ohio River valley. This conclu- sion is supported by the mature profiles of weathering developed on the drift; for example, in the till section on Delaware Road south of Batesville (see. 32, T. 10 N., R. 12 E., south of Bobs Creek, Batesville quad., Indiana) there is exposed about 8 to 10 feet of silttil that contains many scattered pebbles of siliceous insoluble materials. Such deep weathering is not expected in till of Illinoian age. Gooding (1957, 1963) described in this region a single terrace remnant to which he assigned an Illinoian age on the basis of its height (unspecified) above the level of the terraces related to the drift of Wisconsin age and its great depth of leaching-about 18 feet through loess- mantled terrace alluvium into the underlying till. Such a mature profile of weathering is here interpreted to be pre- Illinoian. Because Gooding interpreted this terrace to be of Illinoian age but reported no till that could be inter- preted to be of Illinoian age within the bedrock valley of the West Fork of the Whitewater River, he (1957, p. 28) reached the conclusion that the valley was probably "established" in post-Illinoian (Sangamon) time, thus rejecting the "Deep Stage" erosion of Yarmouth time as the time of deepest stream cutting. This interpretation is open to question when examined and compared with events in the nearby Great Miami River valley, to which the Whitewater River is tributary, and in the Ohio River valley, to which the Great Miami River is in turn tributary. In both the Great Miami and the Ohio River valleys, tills of undoubted Illinoian age are present within the deep bedrock valleys cut in pre-Illinoian (Yar- mouth) time. No remnants of valley trains assignable to a Kansan age have been observed along the Glaciated Ohio River valley, and, as in the case of the valley trains of Nebraskan age, the writer believes that no remnants have survived. That there were valley trains is un- doubted, but because the valleys of Nebraskan and Kan- san time have subsequently been highly modified, it would appear that weathering and erosion have removed all evidence of the presence of valley trains. Similarly, whatever loess may have accumulated along the glacially alluviated drainageways in Nebraskan and Kansan time also appears to have been completely removed by later weathering and erosion in the Glaciated Ohio River valley region. Recognition of a Kansan age for the widespread sur- ficial glacial till formerly thought to be of Illinoian age in southeast Indiana, southwest Ohio, and northern Kentucky changes many concepts previously held. It in- dicates that in this region the Kansan drift was far more extensive than Illinoian or Wisconsin drifts. Deposits of Kansan age overlap earlier deposits of Nebraskan age, which normally extend beyond the Kansan deposits as the surficial till. Thus, the earliest (Nebraskan) glacia- tion was the most widespread, and each succeeding glaciation in this area was less extensive. Furthermore, the topographic position of the tills of Nebraskan and Kansan age indicates that they were much more closely associated in time than were the last two glaciations, the Illinoian and Wisconsin. This suggests that the longest and therefore the most important interglacial time was the Yarmouth, between the glaciations of Kansan and Illinoian age. Sence meets. vies) KANSAN GLACIATION 39 Elsewhere, as in southwestern Indiana and southern Illinois, the Illinoian drift appears to have been the most widespread and to mask the underlying Kansan drift and possibly a Nebraskan drift not yet recognized. This widespread expansion of the Illinoian ice sheet may have been in part due to the character of the terrain formed by erosion during Yarmouth time, the time of greatest Quater- nary stream erosion. Perhaps the terrain, especially in the Great Lakes region, allowed each successive advance of the ice sheets from the northeast to be diverted more and more to the west rather than to the southwest. DRAINAGE MODIFICATIONS RESULTING FROM THE KANSAN GLACIATION Advance of the Kansan glacier and subsequent modification of the Ohio River's flow in the glaciated part of the river valley are believed to have followed a pattern similar to that of Nebraskan age. Inasmuch as the general regional configuration and the time of max- imum expansion of the Kansan ice lobe, or lobes, are not known, it is difficult to reconstruct the exact sequence of events effecting the regional drainage pattern and its modifications. Drainage modifications in Kansan time appear to have been minimal, however, when compared with the drastic changes of the earlier Nebraskan or later Illinoian times. C When the ice sheet of Kansan age advanced into the basin of the Ohio River, the river was a southwestward through-flowing stream from above the ancient Manchester divide to the mouth of the gorge through the Knobstone-Muldraugh Hill escarpment-a course in- herited and stabilized after the modifications caused by the glaciation of Nebraskan age. Except for the channel loop to the north around the Cincinnati area, the river followed a course essentially the same as that of today, although its valley was shallower and its many small tributary streams, largely formed during Aftonian time, were much shorter and had not yet deeply dissected the upland flats to produce the mature topography of today adjacent to the main valley. Drainage modifications of Kansan age along the Glaciated Ohio River valley are, like those of Nebraskan age, highly speculative for want of precise data because of subsequent weathering and erosion. Above the Cin- cinnati area, the Ohio River appears to have been un- obstructed by the Kansan ice sheet, which apparently did not reach as far as the river valley. The valley served, however, as an important sluiceway for glacial melt waters and glaciofluvial outwash from a broad sec- tor of the ice front in Ohio, northwest Pennsylvania, and perhaps even western New York State. In the basin of the Glaciated Ohio River valley, the first blockage of the river by the advance of the Kansan ice sheet appears to have been along the great loop of the river around the present site of Cincinnati. As soon as this sector of the river was overwhelmed, the river up- stream, already swollen by glacial melt waters, was ponded and rose rapidly within the main and tributary valleys. Presumably, the waters of the Ohio-Licking River basin overflowed into the still ice free Kentucky River basin to resume their westward course, but the point at which the impounded waters overflowed has not been determined. When the main valley above Rising Sun (pl. 1) became ice covered and inoperative as a drainageway, part of the melt waters may have been diverted into the lower Ohio through the Eagle Creek- Kentucky River drainageway. Possibly, when the ice sheet first blocked the drainage above Cincinnati, melt-water torrents in the ponded Licking River valley rose to overtop a divide about a mile east of the Anderson Ferry (Covington quad., Kentucky-Ohio). There, two streams, one draining to the east and the other to the west from a col in the divide, may have formed a channel to the west for the release of the ponded waters. If so, this spillway was used only briefly before it was overwhelmed by the ice sheet and rendered inoperable, as suggested by Ray (1966). As the ice sheet waned and the col was uncovered, this. drainageway may have been used briefly once again and may have been further enlarged by torrential stream overflow before the divide again became effective in post-Kansan-pre-Illinoian time. Assuming that the advancing Kansan ice sheet, like the Nebraskan ice sheet, covered the Madison divide area, an assumption not yet proved, then waters along the ice-free Ohio from Rising Sun to Madison were again ponded, and the flow was again reversed up the Ken- tucky River, rising rapidly to overtop a low divide separating the Kentucky River from the Salt River drainage. This divide, as yet undetermined, may have been the same as that postulated for Nebraskan time. Although glacial till of Kansan age has been recognized at places on the south side of the Ohio River valley between Madison and Louisville (Ray, 1957), none has been observed on the uplands south of the valley. Apparently, the Kansan ice sheet was unable to climb from the valley onto the highlands of northern Ken- tucky. In crossing the valley, it must have, at least for brief periods, blocked the river, yet no evidence for such periods of ponding has been observed. Presumably the evidence has been obliterated by later weathering and erosion. Some drainage at this time might have escaped through the Harrods Creek channelway from ponded north-flowing tributaries to the Ohio, but no lacustrine deposits of Kansan age have been found in the presumably ponded valleys. Such lacustrine deposits may have been flushed from the valleys by deep erosion during Yarmouth time. At the maximum extension of the Kansan ice sheet, all melt-water drainage in southeast Indiana, Ohio, and 40 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY farther east was channelled through the two passageways in the Knobstone-Muldraugh Hill escarp- ment in southern Indiana: the channel of the preglacial Salt River now occupied by the Ohio River, and the channel of the combined Muscatatuck River and East Fork of White River to the north. At the close of Kansan time, the Ohio River in the glaciated part of its valley seemingly occupied essentially the same channel as it did after Nebraskan time. The meandering channel of the preglacial Kentucky River between the Madison area and the Great Miami River valley had been somewhat straightened to conform to its present-day route, but upstream, the main stem of the Ohio River continued to follow the great loop to the north around the Cincinnati area. All connections with the obliterated Teays-Mahomet drainage system had been erased during Nebraskan time, and the Ohio was now the dominant through-flowing river east of the Mississippi. YARMOUTH INTERGLACIAL TIME When the Kansan ice sheet had waned and finally dis- appeared from the basin of the Ohio River, Yarmouth interglacial time was initiated there. This, the longest of the three Quaternary interglacial times, lasted until the advance of the third great ice sheet, the Illinoian, into the basin of the Ohio River. During Yarmouth time, the Glaciated Ohio River valley and its drainage basin were profoundly affected by long-continued weathering and erosion. Yarmouth interglacial time marks the most impor- tant break in the succession of Quaternary glaciations, because the deeply weathered, eroded, and highly modified pre-Yarmouth glacial deposits sharply con- trast with the less weathered and eroded post-Yarmouth deposits. In general, pre-Yarmouth glacial deposits do not present a readily distinguishable glaciated terrain, whereas there is little doubt of the glaciated nature of the terrain underlain by post-Yarmouth deposits of Illinoian and Wisconsin age. Furthermore, Yarmouth time was a time of deep stream entrenchment into bedrock, providing the "Deep Stage" drainage described by Stout, Ver Steeg, and Lamb (1943) along the Glaciated Ohio River valley and its tributaries. Since Yarmouth time, the major streams have probably flowed only on thick post-Yarmouth alluvium within their bedrock valleys and presumably are not downeut- ting into bedrock, as in Yarmouth time. If this is true, then by the close of Yarmouth time, relief along the Glaciated Ohio River valley was greater than at any other time during the Quaternary Period. Like the earlier Aftonian interglacial time, Yarmouth time has transgressive upper and lower boundaries. As soon as the glacial deposits of Kansan age were exposed by the waning ice sheet, their modification through weathering and erosion began. Where Kansan drift is still an unconsolidated surficial deposit, weathering and erosion have continued to the present time. Where Kan- san deposits have been covered by Illinoian or Illinoian and Wisconsin drifts, or by loess, they are less deeply weathered, for weathering has been inhibited or ap- preciably slowed by the mantling deposits. On poorly drained upland flats, deep weathering of the surficial Kansan drift, like that of the Nebraskan drift, has left a silty clay, gumbolike residuum largely resulting from leaching of the limestone and silty calcareous shales in- corporated in the glacial drift. The included crystalline rocks, a small percentage of the till, have been almost - completely decomposed and destroyed in the upper part of the profile of weathering, where their absence is con- spicuous. Only small insoluble siliceous pebbles, com- monly so weathered as to be punky, remain. These are scattered at random throughout the surficial silty clays or clayey silts. On the poorly drained upland flats, in areas of ground moraine of Nebraskan and Kansan age, the original clays and the finer weathering products have tended to wash from the slight elevations into the adjacent shallow depressions on the original surface. This levelling process has resulted in a relatively smooth surface underlain by silty, gumbolike clays of variable thickness that in part have formed by weathering in situ and in part have been transported by colluviation from the ad- jacent higher elevations. Where upland areas have remained relatively undissected and therefore poorly drained, the clayey, gumbolike layers of the profile of weathering have inhibited downward percolation of sur- ficial water; thus, subsurface weathering has been slowed, and highly calcareous glacial drift occurs in places at shallow depths below the clayey surface horizon. Where the uplands have been well dissected through the headward erosion of small streams, es- pecially in areas near the Ohio River, the clayey com- ponents of the surficial layers have apparently been flushed from the deposits by ground-water movement, so the remaining product is largely the ubiquitous silt containing the insoluble siliceous pebbles scattered at random throughout. When the Kansan ice sheet melted and probably dis- appeared during the long Yarmouth time, water that had been stored in the ice sheet on the land surface returned to the sea to produce a rise in sea level of in- determinate but appreciable magnitude. At the same time, melt-water torrents and glacial debris that had poured into proglacial drainageways from the waning ice sheet were gradually reduced and eventually halted. Thus, when the ice sheet had completely disappeared from the drainage basin of the Ohio River, flow of the YARMOUTH INTERGLACIAL TIME 41 river was drastically reduced, and glaciofluvial debris ceased to pour into the main river channel. No longer was a valley train of fluvioglacial outwash being built in the Ohio valley. A rising base level for the river, a reduc- tion in flow, and a reduction in introduced load suggested to Russell (1940, 1944) and Fisk (1944) that in- terglacial time was a time of stream aggradation rather than degradation. Field observations, however, do not support such a belief along the Glaciated Ohio River valley, where degradation was predominant during in- terglacial time. The problem of degradation versus aggradation dur- ing interglacial time has been discussed elsewhere by Ray (19652), who was led to the conclusion (p. 28) that: Between the times of glaciation when the [Ohio River] drainage basin was ice free, river volume and velocity decreased sharply. The river, however, flowing on alluvial fill, had available a ready supply of transportable material. Because of the increased channel slope, in- herited from the valley train, the river was competent to erode, thereby increasing its velocity in an attempt to adjust to the new condition. During the long Yarmouth interglacial time, the degrading Ohio River and its tributaries removed most of the glaciofluvial alluvium within their valleys and cut deeply into bedrock along the river valley. Whatever in- equalities may have remained as the result of previous integration of the drainage basins and removal of the Madison divide appear to have been smoothed at this time. The scenic features along the Glaciated Ohio River valley are largely the result of deep stream erosion and entrenchment during Yarmouth time. The deep, steep- walled bedrock gorge through which the river now flows was largely the product of erosion in "Deep Stage" time, when relief along the valley was greater than today. Perhaps the most spectacular section along the gorgelike valley is near Madison, Ind., where for a few miles both upstream and downstream the valley is narrow and its precipitous walls rise almost 400 feet from the level of the river to the adjacent flats of the Dearborn upland or the Muscatatuck regional slope. Short, steeply graded tributaries along this section are characteristic, es- pecially those from the north, whose valleys were large- ly cut in post-Kansan time. For a few miles downstream from Madison, Ind. (pl 2A), creeks draining to the Ohio River from the Indiana bank are short, steeply graded, and sharply V shaped. Small waterfalls are common in these valleys but are unique to these few miles of the Ohio River valley between Cincinnati and its mouth. They are the result of interruptions in the steep stream gradients caused by thick erosion-resistant bedrock layers interbedded in sections of thin shales and shaly or silty limestones. Where the erosion-resistant layers are absent and the valleys are entrenched only in the thin shales and limestones, especially those of the Eden Stage, small riffles and cascades result from the irregular erosion of the bedrock, as pointed out by Fowke (19833) in his description of this part of the river gorge. The largest and most spectacular waterfall is Clifty Falls on Big Clifty Creek, immediately west of Madison, Ind. (pl. 24). This waterfall, about 90 feet high, is the center of attraction in Clifty Falls State Park. Four smaller waterfalls are present in tributaries entering Big Clifty Creek below Clifty Falls. Prior to the deep en- trenchment of Big Clifty Creek in Yarmouth time, probably in preglacial time, Big Clifty Creek may have been the largest creek in the headwaters of the Salt River tributary that followed the present Ohio River valley west from the preglacial Madison divide. Heading on the back slope of Laughery escarpment almost at the east edge of the Muscatatuck regional slope, Big Clifty Creek is generally believed to have followed in its lower course the valley now occupied by Hog Trough Creek, which is separated from the present Ohio River valley by the Devils Backbone (pl. 24). In Yarmouth time, dur- ing formation of the present Ohio River channel across the col in the Madison divide, the valley wall between Big Clifty Creek and the present Ohio River was removed by erosion, and Big Clifty Creek was captured by the Ohio, leaving the Devils Backbone as an isolated hill or "island." A feature somewhat analogous to the Devils Backbone near Madison is present immediately upstream from Carrollton, Ky. (pl. 2B). There, a narrow bedrock ridge separating the valley of the meandering lower Kentucky River from the main Ohio River valley was breached, leaving a bedrock "island" that today rises 380 feet above the normal pool stage of the Ohio River. This bedrock mass, now the site of General Butler State Park, is roughly triangular in outline, and has precipitous walls rising above the surrounding alluvial valley fill and an isolated mass of glacial till. The east and west sides of the bedrock "island" are wide-radius curving slopes marking ancient meander scars of the Kentucky River. The north-facing escarpment marks the relatively straight continuation of the now-breached south wall of the Ohio River valley. Inasmuch as the preglacial Kentucky River followed a now-abandoned high-level channel from a point several miles up the Kentucky River from its mouth to join the Ohio River about 5.5 miles above its present confluence (fig. 10), the great meander sear east of General Butler State Park along the lower Kentucky River is Quater- nary in age. Glacial till in the abandoned high-level channel is interpreted to be of Nebraskan age, so the meandering channel in the lower course of the Kentucky River is believed to be post-Nebraskan in age, probably 42 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY initiated by erosion in Aftonian time. Near the close of "Deep Stage" erosion in Yarmouth time, the narrow bedrock ridge between the Ohio and lower Kentucky River valleys was breached by the widening of the Ohio River valley, and a broad col was formed. There is no evidence, however, that the col was ever crossed by either the Ohio or Kentucky river. Its existence before Illinoian time is, however, undoubted, because a large mass of Illinoian till is present in and south of the col. Lack of informa- tion on the configuration of the buried bedrock surface in the area of the col hinders definite and precise inter- pretations. Thus, the long Yarmouth time throughout the Glaciated Ohio River valley region can be summarized as a time of stream degradation and of cutting of the deep bedrock channels associated with the "Deep Stage" erosion of Stout, Ver Steeg, and Lamb (1943). It was a time of deep and rapid erosion by tributary streams in their attempt to remain graded to the master stream. Headward erosion of tributary streams into the upland flats, glaciated in Nebraskan or in Nebraskan and Kan- san time, markedly reduced the areal extent of the up- lands and improved drainage conditions. A rugged mature topography formed in places along the Ohio valley, especially in the region of the Dearborn upland. Yarmouth time was a time of deep weathering of residual glacial deposits on the uplands and a time of rapid downcutting and grading of the Ohio River valley, especially in the vicinity of the preglacial Madison divide. ILLINOIAN GLACIATION The third great Quaternary glaciation, the Illinoian, is commonly believed to have been the most extensive of the classic glaciations in the midwestern United States. That the ice sheet was wider and spread farther south than any other ice sheet is well known (see Flint and others, 1959). Studies on which this report is based in- dicate, however, that the Illinoian ice sheet in the region of the Glaciated Ohio River valley was not as widespread as formerly believed. Till of Illinoian age in northern Kentucky is now believed to be restricted to isolated patches within the bedrock Ohio River valley and to a narrow belt along the Ohio River for a few miles above Cincinnati (pl. 1; Durrell, 1961; Ray, 19652, b, 1966). Furthermore, the widespread till in southeast In- diana, formerly believed to be of Illinoian age, is here reinterpreted to be of Kansan age or older. Because of the exaggerated local relief produced by "Deep Stage" erosion during Yarmouth time, the con- figuration of the ice sheet of Illinoian age did not follow that of the earlier ice sheets. As the Illinoian ice sheet advanced, it appears to have been so influenced by the topography that in its movement to the southwest it split into two lobes-the Clermont of southwest Ohio and the Jackson of east-central Indiana (named for Jackson County, Ind.)-and a narrow sinuous ice tongue that extended down the Ohio River valley (pl. 1). The highland area centering in Randolph County of east-central Indiana may have been the feature that split the ice sheet, advancing from the northeast, into these two lobes. $ The position of the ice margin between the two lobes is not known, for the glacial deposits of Illinoian age have been covered by deposits of Wisconsin age, and these later deposits rest directly on Kansan till in east-central Indiana (pl. 1). A long narrow winding ice tongue of Illinoian age extended from the east lobe down the valleys of the Great Miami and Ohio Rivers almost to the present mouth of the Kentucky River. The magnitude of this extraordinary ice tongue makes it a feature unique along the margins of the great ice sheets that invaded central United States. Although no data are available on which to base age differentiation of the two lobes in Ohio and Indiana, it is assumed that the lobes were penecontemporaneous and that the ice tongue formed at the time of maximum advance of the east lobe and was presumably of short duration. Illinoian glacial deposits are distinguished in the field by their topographic position, by their modest weather- ing profiles compared with profiles on Kansan and Nebraskan deposits, and in places by their surficial moraines, a feature not characteristic of the older glacial deposits. In Clermont and adjacent counties in southwest Ohio, till of Illinoian age is widespread along the Glaciated Ohio River valley (pl. 1; Goldthwait and others, 1961). It is relatively thin, is normally leached of its primary carbonates to depths of nearly 10 feet, has a flat to undulating, somewhat poorly drained surface, and is present on the uplands as well as in the "Deep Stage" bedrock valleys. Durrell (1961) named this area of surficial Illinoian drift the Clermont Lobe, and described low northwest-trending morainic ridges east of Cincinnati. He pointed out that small tributaries to the Little Miami River tend to be parallel as they follow the shallow swales between the morainic ridges. To the south and east, the trend of these ridges swings to an almost east-west orientation, generally parallel to the valley of the Ohio River along the south margin of the Clermont lobe. When the ice sheet of Illinoian age moved from the northeast into the region of the Glaciated Ohio River valley, the terrain, as a result of erosion, had attained the maximum relief that it was to attain during Quater- nary time. This relief exerted a powerful influence over the movement of the ice, especially along its outer margin, where it was presumably thinner and its forward movement was less vigorous. Thus, terrain became important in determining the local as well as regional configuration of the ice front. In the Cincinnati fue come by- £ ILLINOIAN GLACIATION 43 region and along the glaciated valley of the Ohio River, the influence of the terrain is especially well demonstrated. The ice sheet, moving southwest in Cler- mont County, Ohio, essentially normal to the deep valley of the Ohio River, pushed into and across that valley and moved briefly for a short distance up into the hill lands of Kentucky before finally coming to a halt (pl. 1). To the south and east, where the Ohio River valley was roughly parallel to the direction of ice movement, the glacier seemingly was not able to cross the valley; it was halted and an equilibrium established through melting of the ice sheet by the swollen torrents carried by the river along the ice margin. In a few places, however, small tongues of ice apparently were able to span the river briefly, for, as noted by Leverett (1902, 1929), several isolated patches of till are present on the south side of the Ohio River valley upstream from that sector referred to here as the Glaciated Ohio River valley. As the Illinoian ice sheet moved from the northeast into the vicinity of present downtown Cincinnati, it was impeded by the deep valley then followed by the north- flowing Licking River, and the uplands to the west were not overridden by the ice. Farther to the north, however, the ice was channelled into the broad, deep valley of the southwest-flowing Great Miami River (pl. 1). Here, as along the Licking River, the steep walls confined the ice and inhibited widespread overtopping of the west valley wall, thereby hindering an advance of the ice across the Dearborn upland of southeast Indiana. The Great Miami River valley, because of its depth, width, and direction, provided an ideal chute for diverting and channelling the ice flow to and down the Ohio River valley to the southwest. So effective was this chute for the ice sheet, that the ice was concentrated into a tongue that followed the broad valley now largely occupied by the Great Miami River to its junction with the present Ohio valley and down that valley for about 50 miles, almost to the mouth of the Kentucky River (pl. 1). Durrell (1961; see also Ray, 1965b, c) recognized an ice tongue in southwest Ohio, his Harrison Lobe, and conservatively suggested that it extended from the Great Miami valley into the Ohio valley for about 10 miles. This ice tongue, unique in size along the margins of the vast ice sheets of North America, left many traces of its presence in the form of isolated drift deposits within the deep pre-Illinoian bedrock valley of the Ohio River. Isolated deposits of stony or clayey drift within the bedrock valley of the Ohio River were described by Leverett (1902, 1929), who assigned to them an Illinoian age. He likewise cautiously assigned an Illinoian age to the more deeply weathered drift deposits in the aban- doned high-level valleys on the uplands and to the deposits on the adjacent uplands into which the Ohio River valley had been cut about 500 feet. Although he suggested that the deposits in the abandoned valleys and on the uplands "seem likely to antedate the Illinoian stage of glaciation" (1929, p. 58-54), he appears to have assumed, without stating positively, that those deposits and the deposits within the Ohio valley were all the same age and were presumably deposited by the same ice sheet. This assumption is, of course, not tenable. Examination of the deposits within the Ohio River valley indicates that there are five undoubted till deposits between the mouth of the Great Miami River and the massive deposit of Illinoian till immediately above Carrollton, Ky. (pl. 1; Ray, 1965b, c); several more deposits are questionable only because of the lack of suitable exposures to indicate that they have cores of Illinoian till. The two masses of till of greatest interest, the "Split Rock conglomerate" at the mouth of Woolper Creek and the deposits near Carrollton, Ky., will be described later, after the general setting of the glacial deposits within the valley has been reviewed. To be described first are four masses of well-preserved glacial till on the inside of bends in the river valley downstream from the points of greatest curvature (figs. 12-15). Such deposition and preservation is expectable if the till was deposited from a narrow ice tongue moving down the sinuous, deep, and narrow valley of the Ohio River, for in such locations, till, intermixed with fluvioglacial masses, would be deposited and protected from removal by ice scour. In general, the deposits are similar to those found along the courses of sinuous valley glaciers. Unfortunately, in the till masses preserved im- mediately below the bends of the present river valley, exposures are confined largely to shallow ditches and roadcuts that are only temporarily available for study. Furthermore, younger loess and dune sand of Wisconsin age may blanket the deposits, and few streams have cut valleys that reveal the nature of the underlying material other than by the float along their courses. The hum- mocky surface of the deposits does, however, contrast sharply with the relatively flat surface of the younger outwash terraces along the Ohio River valley that abut against and in places surround and overlap the lower parts of the deposits of Illinoian drift. Likewise, the relatively smooth trimmed steep slopes of the bedrock valley walls are readily differentiated in the field and on topographic maps from the hummocky surface of the unconsolidated glacial till deposited along their bases (figs. 12-15). The best exposure of till examined within the valley (1960) was in a cut along a secondary road through the till mass backing Egypt Bottom, about 400 feet north of Indiana State Highway 156 (fig. 15). Here, almost 5 feet of weathered brown clayey till containing much siliceous insoluble material and partially decom- posed crystalline rock fragments was present im- 44 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY I t 4 | _-4 CONTOUR INTERVAL 10 FEET 0 Ya 1 KILOMETER DATUM IS MEAN SEA LEVEL Figure 12. mass of glacial drift of Illinoian age between sand-dune-mantled alluvium of highest terrace of Tazewell age at Upper East Bend Bottom and bedrock wall of Ohio River valley. The glacial drift has a characteristic dissected topography rising to an altitude of 580 feet. From U.S. Geological Survey Rising Sun, Ky. - Ind., 1961, 72-minute quadrangle. e] 'a|Suepenb anutu-4,) "T96T 'ung Susy Laang jeotSojoan 'g' wou '[[em Aatea yooupaq sam Jo aseq jpup uo usas aq ueo pajoosstp 'pUI 'ung Sutsty ;o yj.0u seq qurod ;o ure;d poo; pug [eIAn|Je aaoge ade ueIOUI[[] JO }Jl1p -g] aunoiy 13A37 ¥3S NV3W Si WnaiLvd H3L3WOTIN L % 0 1334 0L TVAHILNI HNOLNOD 1 1 + I 37IW L % L. TTY S ILLINOIAN GLACIATION 46 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY 84°4a7'30" xi \_J T XT 1 MILE ] ; CONTOUR INTERVAL 10 FEET 1 KILOMETER DATUM IS MEAN SEA LEVEL Ficure 14.-Glacial drift of Illinoian age along bedrock west valley wall of Ohio River. The glacial drift rises above sand-dune-mantled alluvial terrace of Tazewell age at Mexico Bottom point bar to an altitude of 600 feet. From U.S. Geological Survey Rising Sun, Ky.- Ind., 1961, and Patriot, Ky.-Ind., 1961, 7%-minute quadrangle. 47 ILLINOIAN GLACIATION 'alSuripenb 'T961 "put-~4y 'Jjorneg Aaaing [eatS0j0an 'g* wou, '}Jlup [el)®]3 patjueu-ssa01 jsau8ty ay} aaog®e 1J (QZ UeEY] asl 'wopog 1d43g Ye Aa[EA JoAIY OIYQ JO apis YJJoUu uo ade [amaze, Jo ade.1121 pug uny pueg usam1aq adpt1 jour}stp e sur1o; pues aunp pug ssaof 4q parjuetu Jap [elo®|p-'gT Sundry 13A37 ¥3S NvIW Si Wnaivd H3L3WOT7IX L % o 1 1334 01 1VAH3LNI HnoLN09 f _ _ | s7iw I % o O |I 9 C 3 O Aw S $ o 5 want yaamt __ omo y e ret .l . #2" __ , Na . /- Z 'IR X =, <2 E’: x2 N ,/ = G Sp mill) siya =] | ,,// fl, $ ( 3 [es m e ) k? P = I ”f T R) . N t sod Z S X / / } \ A G p \ ¢ G & SV I f V A ps ( ) 6 f K rface between 490 and 500 feet in altitude. From U.S. Geological k valley. Original terrace su nd., 1961, 7/%#-minute quadrangle. xP 5. f 7 Survey Rising Sun, Ky.- of Tazewell age in lower Gunpowder Cre FicurE 19.-Remnants of dissected terrace 84%4 63 anutu-4} L961 "puy-4y 'uojjfoure; Aaang peotSo] -0a5 wou 'apnil}[E UI 199} 00¢ PUE (6p usamjaq adgJuns eutSlup 'Joaty Ayonjuay Jo 4omof ut ade |Jamazg], J0 aog.104 pajoosstp Jo squeuwoy-'pg @HNOIA 13A37 ¥3S NV3W SI WnLvd 1334 Ol HNOLNOD L % 0 : $43 ,98 WISCONSIN GLACIATION 64 Shells from artificial excavation along a dead-end road about 800 feet south of St. Andrews Church Road and half a mile southwest of St. Pauls School, Pleasure Ridge Park (Louisville West quad., Kentucky-Indiana) [Site along tributary of Big Run Creek between a small isolated loess-covered bedrock hill and the Ohio River valley wall. All fossils identified by J. P. E. Morrison, U.S. Natl. Museum] Pulmonate gastropods: Succinea ovalis (Say) Succinea avard (Say) Retinella electrina (Gould) Stenotrema barbatum (Clapp) Stenotrema leai (Binney) Triodopsis multilineata (Say) Haplotrema concavum (Say) Fresh-water gastropod: Fossaria modicella (Say) This assemblage of gastropods indicates a marginal pond habitat rather than open waters. Inasmuch as Retinella electrina (Gould), Stenotrema leai (Binney), and Triodopsis multilineata (Say) are reported to be at the present southern boundary of their geographic range here (J. P. E. Morrison, U.S. Natl. Museum, written commun., 1957), a climate only slightly cooler than that of today may be indicated. Fossils have not been reported from most lacustrine deposits along the Glaciated Ohio River valley, but Pat- ton, Perry, and Wayne (1953, p. 22) noted a few shell fragments tentatively identified as the fresh-water gas- tropod Amnmicola cf. emarginata (Kiister) from a zone 28 feet below the surface of the 40-foot section of thinly bedded lacustrine deposits in the valley of Long Run, near Vevay, Ind. (SE1/4 NW1/4 SE1/4 sec. 16, T. 2 N., R. 3 W., Vevay South quad., Indiana-Kentucky). Wood fragments are common in places in the lacustrine deposits. Some, identified as ash, were recovered from the fossil locality near Pleasure Ridge Park, Ky. and have been dated by carbon-14 methods to be 18, 520+500 years B.P., or of Tazewell age (Rubin and Alexander, 1960, sample W520). An attempt was made to find the locality at Lawrenceburg, Ind., reported by Orton in 1871 to Warder (1872) and interpreted by Leverett (1902) as a soil zone possibly at the top of drift of Illinoian age within the Ohio valley. The locality along the riverbank was only exposed at low water and is now permanently submerged through canalization of the river. No samples of the wood collected by Orton from this site can be found for analysis. Descriptions indicate that the beds mentioned by Orton occupy the same stratigraphic position as beds of Hubert Court in the Owensboro quadrangle (Ray, 1965a). The Hubert Court beds have been interpreted as belonging to the interval of ice retreat that followed the early, pre-Tazewell Wisconsin glacial ice advance. GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY THE POST-TAZEWELL (CARY) TERRACE After an interval of river degradation in post- Tazewell time, another major period of ice advance was followed by a staggered retreat of the ice sheet referred to as of middle Wisconsin (Cary) age. This important fluctuation produced a valley train of fluvioglacial out wash that now forms a terrace below the level of the older, Tazewell terrace. The Cary terrace of the Glaciated Ohio River valley is identical with the low terrace described in the Owensboro area (Ray, 19652). Unlike the older terrace, the younger lacks the mantle of surficial dune sand. Although exposures are absent that would reveal the character of the underlying materials, the Cary outwash is probably composed of sands and gravels similar to those of the Tazewell terrace; overall grain size is perhaps somewhat finer either because the material has been moved a greater distance from its source or because it is in part reworked from the older outwash deposits. The profile of weathering on the sur- ficial silts is immature and can be easily separated from the more mature profile on the Tazewell surface. The terrace surface of Cary age is about 15 feet below that of Tazewell age (fig. 18), from which it is commonly separated by a well-defined scarp. It is 10 to 15 feet above the river flood plain, but only rarely does a well- marked searp separate the two; in most places the tran- sition is marked by a gentle slope (compare figs. 12-15). Because the Cary terrace is subject to occasional flooding, it is not as extensively utilized as a source of sand and gravel and is not as densely populated or oc- cupied by industrial sites as is the higher, Tazewell terrace, which has not been flooded in historic time. When first studying the terraces of the Glaciated Ohio River valley, the writer thought there was sufficient evidence to define two terrace levels between the Tazewell terrace and the flood plain (Ray, 19652). Later, however, he became convinced that there is only a single paired terrace level younger than that of Tazewell age and that the relatively ill defined surfaces and slopes between the flood plain and the well-defined Cary terrace are reduced remnants of the Cary terrace that are related to river degradation during formation of the river flood plain. Similarly, in the Owensboro area, it is commonly difficult to distinguish precisely between the flood plain and the lowest terrace, which was assigned a Cary age. Comparison of the Tazewell and Cary terrace levels readily shows that the gradient of the younger terrace is less than that of the older terrace along the Glaciated Ohio River valley, and that the younger terrace lacks any indication of a deltaic mass of outwash dumped into the Ohio valley below its confluence with the Great Miami valley, as is true of the Tazewell terrace (fig. 18). FLOOD PLAIN OF THE GLACIATED OHIO RIVER VALLEY 65 In general, the average slope of the lower terrace ap- proximates 5.8 inches per river mile between the mouth of the Great Miami River and Louisville, Ky. This is much lower than the gradient of 7.1 inches per river mile for the Tazewell terrace but is greater than that of the present flood plain of the river, which is about 4.6 inches per river mile between Cincinnati and Louisville, a figure based on the altitude of the 2-year flood, prior to canalization of the river, divided by the distance in river miles. The age of the lower terrace is based on the belief that the last major advance of the Wisconsin ice sheet to form an outwash plain in the drainage basin of the Glaciated Ohio River valley was of middle Wisconsin (Cary) age (Zumberge, 1960; Ray, 19652). No later ad- vances of the ice sheet poured glaciofluvial outwash into the Glaciated Ohio River valley. The many minor flue- tuations of the ice sheet of Cary age during its general retreat were so far removed from the Ohio River valley that they exerted little influence. When the ice sheet of Cary age had reached its max- imum point of advancement, drainage and fluvioglacial outwash were channelled mainly into the Glaciated Ohio River valley through such tributaries as the Scioto River valley and smaller valleys upstream or through the prin- cipal channel along the Great Miami River valley. Because no fluvioglacial outwash entered the Ohio valley between the Great Miami and the Wabash, all outwash underlying the Cary terrace below the con- fluence of the Great Miami and Ohio valleys was largely introduced through the Great Miami valley, although a part may have been obtained through the reworking of the older, Tazewell deposits upstream. Thickness of the outwash of Cary age cannot be es- timated, for no differentiation seems possible between the Cary and the older, Tazewell outwash. Drilling records studied in the Owensboro area revealed no possibility of a separation of the outwash into distinct and datable units. The time interval between dissection of the Tazewell outwash and deposition of the Cary out- wash is believed to have been so short that the Cary out- wash was deposited on the eroded surface of Tazewell and perhaps earlier outwash within the bedrock river valley and not directly on the bedrock valley floor. In general, the areal extent of the Cary outwash plain was so limited within the narrow bedrock valley of the Glaciated Ohio River, and the time of its availability as a source area for deflation of loessial sediments was so short, that no recognizable blanket of loess appears to have been deposited on the adjacent hill lands. Whatever deposition may have occurred, the sediments were necessarily so thin, so readily weathered, and so mixed with the underlying soils that they are indistinguishable as a separate depositional unit. POST-CARY ALLUVIAL HISTORY About 13,000 years ago, the ice sheet of Cary age began a pulsating retreat from its position of maximum advancement. At that time, degradation by the Ohio River presumably began. Although waning of the ice sheet was interrupted by a series of minor glacial re- advances that produced small moraines (Flint and others, 1959), degradation by the Ohio River was presumably unimpeded. Because fluctuations of the distant waning ice sheet were minor, the resultant changes that would have affected the regimen of the main stem of the river were smoothed out to the point of disappearance along tributary glacial sluiceways before reaching the river. At an unknown time during recession of the Cary ice sheet, the ice front retreated from the Ohio River drainage basin above Louisville, Ky., and the river was freed permanently of the direct influence of the Quater- nary glaciers. All ensuing events are, therefore, either nonglacial or postglacial. Although the drainage basin of the Ohio River above Louisville was ice free, the main stem of the river was indirectly affected by the last fluctuations of the linger- ing Wisconsin ice sheet, for the rate of stream degrada- tion was governed by the influence of the ice sheet on climatic conditions. Presumably, as the ice sheet con- tinued to wane, the climate became somewhat warmer and drier, and the average annual flow of the river somewhat less, so that conditions more closely resembled those of today. Climatic fluctuations were presumably so slight that the extremes of temperature and precipitation, though sustained for longer periods, were no greater than the extremes recorded today dur- ing unusually cold or wet periods. FLOOD PLAIN OF THE GLACIATED OHIO RIVER VALLEY The last recorded event in the history of the Ohio River is the formation of the present flood plain through degradation and lateral shifting of the river in late glacial and postglacial time. Formation of the flood plain along the Glaciated Ohio River sector has followed the same principles outlined for the formation of the flood plain in the Owensboro area (Ray, 1965a, p. 25-28, 50-54). The flood plain is an alluvial surface constructed largely by lateral accretion of channel deposits along the shifting river and to a minor extent by overbank deposi- tion during flooding. Because of the narrow bedrock river valley, shifting of the river has been inhibited, so the flood plain is restricted in areal extent and is thus less important as a geomorphic feature of the landscape than one would expect along a river of such magnitude. This narrow flood plain is in marked contrast to the broad flood plain of the Alluviated Ohio River valley 66 downstream. Except for temporary or semipermanent summer cabins, which in places line the river banks, the flood plain is almost devoid of habitations, for it is nor- mally inundated on an average of every 2 years or less. Formation of the flood plain, initiated by the process of river degradation during the waning and dis- appearance of the Cary ice sheet, was rapid at first, but the rate of degradation decreased as the flow of the river decreased, so that today the flood-plain surface has almost reached a point of stability (Johnson, 19836). River activity is now primarily confined to whatever lateral shifting of the channel is permitted by the con- stricting bedrock valley. Late-glacial (Pleistocene) events in the formation of the flood plain cannot be distinguished from recent (Holocene) events. Because the flood plain has formed during Wisconsin glacial time as well as Holocene time, it has been assigned to the undivided Quaternary Period. Because the Ohio River has been canalized by high- level dams, it is now so artificially controlled that its normal pool stages above the dams consist, in the Glaciated Ohio River valley, of three steplike levels (fig. 18). Under natural conditions, the height of the flood plain was almost coincident with or only slightly above the altitudes of the 1- to 2-year floods (Leopold and Wollman, 1957). Furthermore, the normal flood-plain surface commonly terminated at the river in a high, steep to vertical bank above mean water level. Now, however, because the river does not fall below the regulated pool stage, the flood plain can be observed at a wide range of altitudes above the regulated river level. For example, the altitude of the 2-year flood, before con- struction of the Markland Dam (Mile 531.8), was 456 feet (table 1), almost coincident with the present normal pool stage of 455 feet for the river above the dam. Upstream, the difference between the altitude of the river at pool stage and the altitude of the 2-year flood increases to a maximum at Mile 436.3, immediately below the Meldahl Dam. There, the 2-year-flood altitude was 493.3 feet, or 37.3 feet above the pool stage of the waters impounded by the Markland Dam. The normal stage of the pool impounded by the. Markland Dam, which is almost midway along the Glaciated Ohio River valley, is 35 feet above the normal pool stage below the dam (fig. 18). This high stage created behind the dam has resulted in drowning of the lower courses of small creeks as well as major tributaries, such as the Great and Little Miami Rivers (figs. 21 and 22) and the Licking River. Small alluvial islands and sand and gravel bars have been in part or wholly submerged. The effect of the dams on sedimentation in tributary valleys was not noticeable in 1968, but silting of the GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY TaBLE - 1.-Two-year flood altitudes along the Ohio River before con- struction of high-level dams [Locations and altitudes from U.S. Geol. Survey and from U.S. Army Corps of Engineers, Louisville District Office] Flood altitude (ft above sea level) Location River mile Meldahl Dam ---------------~------------- 436.2 493.3 Moscow, Ohio 442.7 491.5 California, Ky 447.5 490.0 New Richmond, Ohio ---------------~-------- 450.0 489.3 Melbourne, Ky ---------------------------- 458.3 487.0 California, Ohio --------------------------> 462.7 486.0 Cincinnati (gage), Ohio --------------------- 470.5 483.3 Bromley, Ky 475.4 482.0 Fernbank, Ohio----------~--~-~-~-~--------- 483.1 478.0 Great Miami River (Ohio) ------------------- 491.0 474.5 Lawrenceburg, Ind ------------------------ 493.0 474.0 Aurora, Ind 496.7 472.0 Belleview, Ky --------~~-~---------------_- 503.0 469.7 Rising Sun, Ind 506.1 468.0 Hamilton, Ky 515.1 464.0 Patriot, Ind 519.3 462.0 Warsaw, Ky 528.2 457.7 Markland Dam --------------~----~-------- 581.8 456.0 Ghent, Ky 537.9 454.0 Carrollton, Ky 545.7 450.0 Madison, Ind ------------~----------------> 557.8 446.0 Corn Creek (left bank) ---------------------- 571.0 441.5 WeStpOrt, Ky 580.7 438.5 Utica, Ind 596.5 433.8 McAlpine Locks (upper gage)---------------- 606.7 430.6 McAlpine Locks (lower gage) ---------------- 607.4 428.5 Mill Creek Cutoff (left bank) ---------------- 616.3 426.0 Mill Creek (left bank) ------- 625.5 424.0 West Point, Ky. (Salt River) 630.0 423.0 flood-plain surfaces immediately above pool-stage flooding in tributary valleys presumably will be accelerated where the water levels have been raised. Alluvium transported from the upper valleys of the tributaries will be deposited in the ponded waters of the flooded lower valleys. Furthermore, canalization of the river may inhibit point bar formation, although never of major importance, and relief on the flood-plain surface may be reduced and in time erased through overbank deposition in swales and depressions. The limited areal extent of the flood plain indicates that shifting of the river has been minimal and will, in general, continue to be so, largely because the narrow bedrock valleys and the impounded waters inhibit the shifting of the river channels even during flood stages. In places the flood-plain surface is well defined between the river bank and a low scarp about 10 to 12 feet or more high that separates it from the older and higher Cary terrace. Elsewhere, the flood plain is dif- ficult or impossible to define exactly, for its surface and the surface of the Cary terrace merge in long gentle slopes. When the surfaces cannot be separated on the basis of altitude, other criteria are necessary. Where scouring by flood waters has reduced parts of the Cary terrace to or almost to the level of the flood plain, the t- < FLOOD PLAIN OF THE GLACIATED OHIO RIVER VALLEY 'a|suepenb 'tg61 'otyp-put-4Ay 'Binqaouame7 Aaamg 'g'p wou - 'zZ andt; jim areduo; *LP8T UI J9AIY IWretpy Je2a11 Jo jouueyo ureu se ured pool; uo 1apuratu pauopueqy _ 'eale UI Joo; zz £q 10a11 Jo adeqs jood paste yoym - 'wreansumop sat g'gg qnoge '(g'Tgq allJ() WeQ JO uone[[E]sUI adojpag doArY OTYQ PUE IWeIpy Jea11 JamoT-*'TZ sunol4 13A37 ¥3S NV3W si waiva H3L3WOT7IN 4 % o 1334 OL HNOLNOD I 1 T 4+ __ t 3TIW L A 0 Oo SP “$me mmuwm $ \ 053 gark.--4- GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY 68 'ofsuepenb 'T96T 'Bingaouamme7 'g' wou, 'IZ inst; YJIm *popoot; 4jired aoaty tuwretpy jea11) ;o poauopueqe pug asinod Jomo] 'joo; zz poste1 surea.ys Jo aBeqs joog 'Wwearsumop a'gg '(g'TgS a[IJ() Wed puepfep Jo uonarduo9 aaye OIYQ PUB Jea11) Jamo7T-Z7 sunol4 1337 ¥3S NV3W SI WniLvd HJLI3WOTIX L % 1334 OL TVAHSLN! HNOLNOD [ | T £ o-oo ,05.pr8 90,68 o THE FALLS OF THE OHIO 69 point of separation between the two surfaces may be in- distinguishable. In the Owensboro area, where this is true, the conclusion was reached that the flood plain could be defined as that area across which the river channel had moved so that the underlying deposits have been shifted and reworked by the river during flood- plain formation. Although this criterion is believed to hold for the Glaciated Ohio River valley, it is rarely possible to use, and one is commonly required to rely on the patterns of areal distribution of the two surfaces and on the alinement of surficial features as they relate to pres- ent river activity. Even this, however, may be inexact, for the lower parts of the reduced Cary terrace may be subject to scouring and to the same periodic flooding as the flood plain. In some places, however, the two sur- faces can be distinguished on the basis of weathering of the surficial sandy silts, for silts of the Cary surface, where undisturbed and uneroded, have developed a profile of weathering which, though immature, is zonal, whereas the silty and sandy soils of the flood plain are azonal. The flood plain is underlain by deposits as thick as 15 to 20 feet or more of yellowish sandy silt and silty sand containing scattered interbedded lenses of fine pea-sized gravel that is generally subrounded. Gravel is composed largely of chert but has minor amounts of crystalline rock. Below the surficial silty deposits is a thick layer of subrounded to rounded gravel intermixed with coarse to fine sand reworked from older deposits. The thickness of the coarse material at depth varies greatly and is generally not known. In some places the flood-plain deposits may extend to bedrock; elsewhere, they may overlie earlier outwash, from which they were in part derived and from which they cannot be distinguished. Because flood-plain deposits are largely reworked from older deposits, they are of similar composition but of somewhat smaller grade size. Peaty humic beds interbedded in the alluvium have been reported to the writer in some areas, but none have been observed. Presumably, overbank deposition has left thin and insignificant deposits on the flood-plain surface during normal flooding. Scouring is presumably done during the higher floods when even the surface of the terrace of Cary age is inundated. THE FALLS OF THE OHIO The only break in the smooth parabolic gradient along the Glaciated Ohio River is at the Falls of the Ohio, between Clarkesville, Ind., and Louisville, Ky. (New Albany quad., Indiana-Kentucky). There, where the river valley crosses the Scottsburg lowland and is at its widest, the river unexpectedly tumbles over bedrock ledges in a series of rapids and small waterfalls. In a dis- tance of less than 2 miles, the river before canalization descended about 26 feet (Fenneman, 1938). Because the "falls" were a serious obstruction to pioneer river traffic, especially during low-water stages, the first attempts at regulation were made early in the 19th century. Today, the McAlpine Dam dominates the "falls"; normal pool stage is 383 feet below the dam and 420 feet above the dam, a difference of 37 feet, or 11 feet greater than the reported natural river levels before canalization. The resistant ledges of bedrock that obstructed the river and caused the falls are of Middle Devonian age and are, in part, the classic coral reef, well known to paleontologists (Hattin and others, 1961). Today, the highest altitude of exposed bedrock is slightly more than 400 feet, whereas nearby remnants of the highest alluvial terrace of outwash of Tazewell age are at an altitude of near 460 feet. Before aggradation of the Ohio River valley, the river in the the vicinity of the Falls of the Ohio was en- trenched in a bedrock channel. This channel, described by Guyton (1946) and MacCary (1955) as having a den- dritic pattern of small tributaries, is now buried under - about 130 feet of alluvial outwash. The alluvium in this channel, especially valuable as a reservoir for ground water, underlies part of the City of Louisville, Ky., south of the present river. Presumably, the channel is either the preglacial channel of a branch of Salt River or a later channel cut by the Ohio during the "Deep Stage" en- trenchment in Yarmouth time. Although available in- formation is insufficient to suggest either age, the later appears to be the most likely. A less well defined buried channel in bedrock was reported by Siebenthal (1901) north of the present Ohio River in Indiana. Siebenthal assigned it a preglacial age. Here again, sufficient data are not available to demonstrate the age or the relationship of this channel to the channel under Louisville.: Presumably, in Tazewell time, fluvioglacial outwash aggraded the bedrock river valley to an altitude at which the river flowed on its own alluvial deposits unhindered by the configuration of the underlying bedrock surface. Later, when degradation took place, the river did not follow its earlier bedrock channel but was superimposed on what appears to have been a small bedrock divide separating the main valley beneath Louisville from a small tributary valley to the north, a tributary possibly related to the channel noted by Siebenthal. Because of the many manmade changes during ur- banization of the area around the Falls of the Ohio, no attempt has been made to determine precisely when, other than in post-Tazewell time, the falls formed. Presumably they are so youthful that there was little incision of bedrock before canalization of the river. 70 GEOMORPHOLOGY AND QUATERNARY GEOLOGY OF THE GLACIATED OHIO RIVER VALLEY BIG BONE LICK, KENTUCKY The classic vertebrate fossil locality at Big Bone Lick in northern Kentucky, about 20 miles southwest of Cin- cinnati, Ohio, has been known for more than 200 years. The geologic history of the bone-bearing alluvial deposits in Big Bone Creek valley is intimately related to that of the nearby Glaciated Ohio River valley (Schultz and others, 1963, 1967; Schultz and others, in Ray, 1965¢c). The site of the lick, a swampy meadow surround- ing salt and sulfur springs in Big Bone Creek valley at its confluence with the valley of Gum Branch, is 2.75 air- line miles northeast of the confluence of Big Bone Creek with the Ohio River (Rising Sun and Patriot quads., Kentucky-Indiana). In the vicinity of Big Bone Lick, drifts of Nebraskan and Kansan age are present on the uplands; drift of Kansan age is also present in valleys cut below the up- land level in post-Nebraskan time (Leighton and Ray, 1965; Ray, 1966). Drift of Illinoian age is present only within the bedrock Ohio River valley and on a low divide between Big Bone Creek valley and the valley of a small tributary to the Ohio about half a mile northwest of the fossil locality. The oldest of the alluvial terrace deposits at Big Bone Lick are referable to Wisconsin (Tazewell) time. The terrace of Tazewell age in Big Bone Creek valley is represented by erosional remnants along the valley walls adjacent to the fossil locality. These remnants are composed of a compact slack-water lacustrine clayey silt deposited when the valley was ponded at its mouth by an outwash train of Tazewell age within the valley of the Ohio River. Today, erosional remnants of the Tazewell outwash plain are present as extensive terrace remnants along the Ohio River above the present level of flooding (Ray, 1965a, b, c). The lacustrine deposits, which are ubiquitous in the tributary valleys, and the prominent terrace associated with them represent typical slack- water alluviation in the formerly ponded tributary valleys along the main stem of the Ohio River valley (figs. 21 and 22). Where lacustrine deposits have been exposed by ar- tificial cuts to depths greater than the depth of leaching, they are calcareous, blue gray, and in most places filled with myriads of secondary calcareous concretions. Where these concretions have accumulated on the eroded surfaces, they are diagnostic of the Tazewell lacustrine deposits (Ray, 1965a). At Big Bone Lick, no vertebrate fossils have been recovered from the deposits of undoubted Tazewell age. The type skull of Bodotherium bom bifrons (Harlan) may be an exception, however, for it is said to have been collected at Big Bone Lick by William Clark during the 1807 expedition sub- sidized by President Thomas Jefferson. Plant remains recovered from the cranial cavity of this skull have a radiocarbon date of 17,0004600 years B.P. (Ives and others, 1967), a date that can be construed as Tazewell. If this skull is truly from the Big Bone Lick site, it can, on the basis of the radiocarbon date, only have been recovered from the lacustrine sediments of Tazewell age. In post-Tazewell time, intervals of erosion and alluviation produced two terraces below the Tazewell terrace and above the present flood plain of Big Bone Creek. These are now represented by erosional remnants at altitudes about 10 and 22 feet above the level of the creek. Unlike the terrace of Tazewell age, the younger terraces are subject to periodic flooding. The alluvium of the highest post-Tazewell terrace con- sists of a surficial deposit of 12 feet or more of leached mottled gray silt with rusty iron staining. A zonal soil has been developed on the terrace surface. Below the surficial leached alluvium is a 1- to 3-foot layer of calcareous, deeply iron stained, gravelly, sandy silt from which wood and the bones of Mammut americanum, Mammuthus sp., Bison antiquus, Odocotleus sp., Equus cf. complicatus, and Paramylodon sp. have been recovered. A radiocarbon date of 10,600+250 years B.P. (Levin and others, 1965, sample W1358) obtained from the wood indicates the age of the fauna but not the age of the terrace surface, which may be considerably younger. Unconformably underlying the bone-bearing zone is an uneroded remnant of compact calcareous blue-gray lacustrine sediments believed to be of Tazewell age. There is no indication that these sediments are Tazewell sediments that have been reworked in post-Tazewell time. On the lowest and youngest terrace surface are the salt springs and surrounding meadowland of the lick. Excavations in this terrace revealed 10 to 12 feet of calcareous sandy and clayey silt leached only to a depth of about 2 feet below the surface; no zonal profile of weathering has been formed. At depth, a layer of black humic bone-bearing gravelly silt in places overlies a barren blue-gray lacustrine valley fill, presumably of Tazewell age, that is similar to the lacustrine deposits under the higher terrace. The bone-bearing horizons of the youngest terrace deposits are divisible into three zones. The first, 7.0 to 8.5 feet below the terrace surface, contains an association of modern bones and manufacts mixed with older bones, suggesting that this zone has been disturbed in historic time, possibly during earlier paleontological excavations. Bones of Canis sp., Bison bison, Bos taurus, Sus scrofa, Odocoileus virginianus, and Equus caballus were recovered from this zone. The second zone, 8.5 to 11+ feet deep, is a dark-gray to dark-brown humic silt and sand. Bones of Bison bison, IPsec on p e oy o e ao . pd as REFERENCES CITED 71 Bison sp., Ovibos sp., Cervus cf. canadensis, and Odocoileus sp., and of proboscideans, Bison ef. antiquus, and Equus ef. complicatus, are present in the basal part of this zone. Because no bones were articulated and no bones of modern animals were intermixed, this zone appears to have been reworked by stream action from the underlying deposits that compose the third and oldest zone. The third zone, of variable thickness, is present from depths of about 11 to more than 15 feet. It is a blue-gray silt that may be of Tazewell age, but more likely it is composed of Tazewell sediments reworked by stream ac- tion in post-Tazewell time. From this zone, bones of Mylodon sp.. Mammut americanum, Bison antiquus, Cervalces scotti, Rangifer sp., and Equus ef. complicatus have been recovered. The underlying dark, blue-gray clayey silt, almost inseparable from the lowest bone- bearing zone, has been excavated to a depth of 29 feet and may be either the original slack-water sediments of Tazewell age within the Big Bone Creek valley, or, like the overlying bone-bearing zone, the sediments of Tazewell age that have been reworked by stream action in post-Tazewell time. Augering in the Big Bone Lick alluvial flats indicates that the maximum depth to bedrock is 32 feet. No organic materials have been recovered from the basal deposits that could provide a radiocarbon date to indicate whether the blue-gray clayey silt between the bone-bearing zone and the bedrock of the valley floor is of Tazewell or post- Tazewell age. Of the three terrace levels above the flood plain of the creek at Big Bone Lick, the highest is correlative with the Tazewell outwash plain in the Glaciated Ohio River valley and appears to be devoid of a vertebrate fauna. Only deposits of the two younger and lower terraces of post-Tazewell age contain productive bone-bearing zones. An undisturbed bone-bearing zone under the higher post-Tazewell terraces is dated between 10,000 and 11,000 years B.P. The bone-bearing deposits associated with the younger and lower terrace are believed to be in part reworked by stream action from the older deposits during the formation of the terrace and in part disturbed by excavations in this terrace in historic time, as attested by the presence of the bones of domesticated animals, crockery shards, articles of clothing, and other manufacts that are mixed with the bones of ancient or extinct animals. The so-called Big Bone Lick fauna may largely date from a time about 10,000 years B.P. REFERENCES CITED Bownocker, J. A., 1947, Geologic map of Ohio compiled by J. A. Bow- nocker; reprinted 1947 with revision of glacial boundary by George Willard White, and with changes in base map: Columbus, Ohio, Ohio Geol. 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G., eds., 1965, The Quaternary of the United States-A review volume for the 7th Congress of the Inter- national Association for Quaternary Research (INQUA): Princeton, N. J., Princeton Univ. Press, 922 p. Zumberge, J. H., 1960, Correlation of Wisconsin drifts in Illinois, In- diana, Michigan, and Ohio: Geol. Soc. America Bull., v. 71, no. 8, p. 1177-1188. eu 620000 A Page Abandoned valleys, high-level. See Preglacia! high-level valleys. Kentucky River meander .................. 41, 48 River.. .. .. . o.. o c aR rae nne. 13 Acknowledgments ..> .\ "//. .. 1s co 6. cence ance 4 Aftonian interglacial time , .......2......22....220 . 33 Airport SecHon§ :. 78.202.) -..: rss + rhe 26, 34 Anderson Walley -.; ......) . 15, 16 B Barbed Lributaries, . ... ysis ee an 2 AP e . are 17, 18, 52 Barriers to ice movement, Cheviot prong ............ 54 Great Miami River valley .......... ... 48, 54 53+... : Reids c. an are nd 43, 54 21302. 200.00 k lae bee ra a Fack idan ard 1 l wont 39 Knobstone-Muldraugh Hill escarpment ...... 35, 37 Licking River valley .. . ..... .. ...= 060. come cers 43 Ohio River valley .;... 39, 43 proglacial drainage : .. :... . ce » 50 Bedrock, bench, Aftonian ............ 28, 34 bench, Kansan drift ............. . .. 84, 36 control of drainage patterns .................... 10 control .of topography . ..; . : ... .32 0.0007 00 er 9, 58 formations .. :. :... ...s. .so cc 9 rare islands +>. .. na c riers s reaps aragon 41 1ed@es . .; 72. aire bane oo as ih Poiana ne tiie a 69 Sangamon erosion ............... valleys, buried tributaries. ...... 69 Ohio River,... . 1.10. cope 4, 43, 49, 65 S10PB 23. - +15 s die crank bis s nace raves bere sc l s 18 Yarmoutit @roglon . 2 s¢. cores nein e Al Blg Bone Lick, Ky: :2.1. ... T2. i? deel cd: e+ cen nake 70 Big Clifty Creek .. 2; . 2. .s 0. 00004 aren roar epe 41 Big Sugar Cregit >. ... 15 :... cs renale a skirt rre n+ 18 Bluegrass region ...... 1. . : on T, 8, 18 Bypass channels, Illinoian ..................... 54, 56 Nebragiah ~. 2 is 00 30 200000 deba nerve 32 C Calcareous COnCTeVIONE UF, ... :. .. 29) iver ree i reed 70 Canalisation .. :.. s 195. ss oie Ai ies dee a 66 Carbon-14 dates .. 59, 64, 70 Carrollton, Ky! ... . . a as 2. redfeide sno noe ++ r coe we 41 Chesnut Ridge ~. 790-000... 109 oto opaca ae 37, 49, 50 Cheviot prong oii. ver . «51, 52, 54 (Cincinnati a. c. 1.9.1 2s 20, 0. . sre an ro canine 7 Cincinnati area, barbed tributaries ................. 52 Illinoian drainage changes .................... 51 Kansan drainage changes ...................... 39 loop abandonment . ;. . . ..; cs. 02. 51, 55 preglacial drainage ............ ... 18, 58 pre-lilinolan drainage ... %.... .+ c n+ 51 Cincinnati River .. .. 13, 30, 53 Cincinnati soll eerige 1712202... 020010 + eral eee ng a + 24 Clermont 1obe ...... .. cavs 2 oy re reared nbn 42, 51, 56 Cleves} Ohio?: : +. . . . sors. .as d to C tR ae ned 52 Clifty 2. +:1. . 0927. . «vader aer s +s ie 4, 41 Commissary Cornet . .- ..... be ae adele nc ane a 36 Cofaliteet . i: se, 22. A. Th 2 n+ a si nn cher ca 69 Covington Ridge .. . :. 22.00.20 ..or readin icra +a ihan as 48 D - . : 2. . .. 12% ... con n/ r e 25, 33 Dame/ McAlpine :s. .-s.. . . . ... crete ro nent inn 69 Markland >.. 2 9208. . ous. 11 . vea nia cie +n r 18, 66 Meldah! +., ih io ... ie i+ bae rere eon a d 66 INDEX [Italic page numbers indicate major references] Page Dearborn-upland . :s 280.2. : Teres cl net ed raleance 9, 24, 42 "Deep Stage" erosion ........... ... 38, 40, 51 Definitions, Bluegrass region ..... ................... 9 Ohio River valley sectors .................... 2,3 physiographic province boundary ................ 7 Deflation of valley rails. 2 2 : 1 12200 0040 14.0052 mule 59 Devile Backbone :. . : . 27.1 .° 1060s con an 1 n+ 41 Devonian-toral reef. .. .... .\. luvs lll. ol aga 69 Divides, Anderson Ferry 120... 22 00008 « 200002 . 39 between Kentucky and Salt River basins ........ 32 between Wabash and Ohio River basins .......... 4 between Whitewater and Ohio River basins ..... 37 Cheviot prong .............. Cincinnati area ............ Dayton, Ohio - 121+ . . os ou de abe 14, 16, 19 Alliolan 223... : 1 5s. anes +s cetera s 52, 58, 55 Kensal. 54 su for: 1s 12s daran cee coed co a 39 Loughery escarpment . .;. .; 9, 16 Madison, Ind. See Madison divide. Manchester, Ohio. See Manchester divide. Miximilown, Oh1G :: 2324 542202 dicha ae ear a Mee dir a 53 Mount Hope Church, Ohio ................. 58, 55 near Ohio River Mile 488 .................. 52, 55 Nebragkan : +.. . 1.4 11.3 00002 Toh a 2000 a ak 30, 32 New Baltimore, Ohio.. . .. .... luat ees 538, 55 New. Martingvilie, W. Va.....) 2.20200. 20.0 30 pregiatial .. . . ype abasic a 12 ave ih mas 14, 19 @flurian formations ... icicle. 222022 } oh s 14, 19 Walnut Hills prong ../. 32.5 sue vien 52, 58 Drainage, bedrock control, . . .sy. 22.2000 00% 10 divides. See Divides. preglacial. See Preglacial drainage. Drainage modifications, Illinoian ................... 51 Illinoian, bypass channels.................. 54, 56 Cincinnati atea a...... l 51 Cincinnati loop abandonment 51, 55 disruptions due to ice tongue ........... 55, 56 initial disruptions; .s. ... 30. 92.0. 99.9 ie.. 53 reversale In flow . ss ".s. ann . . 55 Kangan a. evra vance. in deities a 39 Nebraskan as . .s :o coors arene 50 a 29 above Manchester divide ................... 30 between Manchester and Madison divides .. 31 bypass chattels. ..o 22 030. naren nd 32 Bagle Creek mins r 2+ c cers on 32 reversals In flow . 52.22. cel Aud dL 30 Salt River sss iss sor 31, 33 timing with ice advance ............... 30, 31 west of Madison divide ..... s.............. 33 Drift, Illincian. See Illinoian drift. in bedrock Ohio River valley ............... 43, 49 intermixed with outwash 48 Kansan. See Kansan drift. Nebraskan. See Nebraskan drift. pre-Wisconsin, age determinations ............. . 37 Kentucky © 15.2 . 1132 reer mie dt i e dan dnes marg vi relation to topograplty .... . .-.. ... d 9 Southeast Indiana -. ... . 0s .s. .us reed 38 surficial in southeast Indiana ........... 28, 24, 38 valley-fill . :s mass . 0. c Lees anenome ra an 5+ 34 WOOU-bearIh@ *. . . : .., . as nn al. rile capea 25, 95 Dry Oreck . s2 902 onle. a a nal ae a +0 a 18, 52 Diings as offs) c, ene tie area sree oie ville th ane +a 60 E Eagle Crogk .%. .... o. o, . re carbs 59d 18, 32, 61 channel ...... ...... . s ole 17, 18, 20 Oreek.~ ... . .:} .... ?. oF pain tan Pate ts 52 - 2. 120000. 2002 .co e h re aad 28, 33 »Page Erosion-Continued Airport sections s 52 2 i150 2 0. re onenh 28 bedrock ss us eil ce sel ort ne aer s L meld an cee 41, 57 Bluegrass region /:... ..... cool kira a 9 "Deep Stage "a.. .. .. . oi. non reine 38, 40, 51 differential ... Jessamine dome . levelling processs ...... ..; lanai 1. 22.0. s Pleasant Valley section .; ...... ; . :i zsi: 28 + . .s. 50s ... Coph in aren ries 11 Sangamon , . . 10007. - io noen env lan se dus + cel 57 SCenie , . seco ar on iret nar nen d Al stream entrenchment ................... 11, 40, 42 Yarmouth. . . : 2.20 caren le Phonan eae nls 28, 41, 42 Escarpment, KnobstoneLMuldraugh Hill. See Knobstone-Muldraugh Hill escarpment. DRUGHENY >. 1.01. s 1 e+ ian ean oue 9, 10, 16 Exposures, Batesville; Ind . . :- . . cor- s coons st rages 38 Big Bone, Ky.. ...>. :a 24s 48, 70 Butter Falls, Ind .; :. ....26 drift in Ohio River valley ......... 43, 48 dune Sande 1. 71. lel), .. cor va o an 60 Reypt Bolan: ..... . 2 1. be fi oren wer 43 Flagg Spring Church ............. Illinoian conglomerate ............ drift... .. .. 0... .~. Kansan drift? ... .. 2202s ane r+ ae Lookout Heights ...:..........}.. Madison uplands .yz....1 ...... 0% Nebragkan drift . ...... ;. 23, 26, 29, 34 Pleasant Valley: Road . :.... . ut) nowis ic a 29 Riddles Bun.- .t... 200.0 : 1.04 St. Agnes Church :.... .s -M. m rear. . 26 Twelvemile Church ;. ... :; ron desnuda iela . 54 Wisconsin (Tazewell) outwash ... ............... 60 See also Stratigraphic sections. F Fallsrof the Ohio 45 ; ... :-. . csf dfs 1s r» neer chen 69 Farmdale Loess : .. 212+, aca on. hr rare on 59 Ficidwork: .... . . ..; . . LL r eae dcalah s £ 135 1 Behar tian alg 4 Flag# Spring Creglcsse a. ite... 2 90 91 2. al 54 Flood Alfitudes .. ..-... ... . 50 -.... ... 000k caine Bagno / . 66 Flood plain of .Ohto River : 0+: aol on eres cle d 65 Fluviatile deposits. See High-level fluviatile deposits. Fluvioglacial deposits, Tazewell ... .................. 60 Fossils, Big Bone Lick,; Ky ::- ...s. 0s pes aires 70, T1 bones : /.. . . 2s seme as f opal au s Rie a ae 70, 71 mammoth ...... HigStadon 2 on cei. io waive 3 > tthe al 60 Pleasure Ridge Park, Ky ................... 61, 64 post-Tasewell .. +s .s3 mum or cain. dr a+) 22 70, 71 shells -.. .s an .s . alf sere vi cide al 64 SEUIL ;.. Ayr c od, soit a onn dairies rf vans mals + + » 70 0.7102. ory erd 59, 60, 64, 70 §@BUH : 227220 21 382 32. . 1 . cle ya van t (Udu iret 60 vertebrate -:... cls on. ould . ooo 70, T1 WOOd: . 1 13 ihm Wanton irl dy vies imns sie 59, 64, 70 Fourmile Oregl . . ..)... cou) Nii 21 ce ois Pee dri ng 17 G, H General Butler State Park .., . ..... ... 00.20 202 41 Gilbert Creek . .... 0% .si. ri. [ols cal 20 Glaciation, disruption of Teays-Mahomet River system . .21 extent of succeeding ice sheets ................. 38 fifet . ; . . :s. .s c. non cent Seit rons,, 21 pre-Illinoian, evidence ..................... 26, 29 Goose Oreck 2" .~ e.. l onl oneal rin ir na te a 54 75 76 Page Gravelplts :- 22.2 ss ovde rxaea saith erin ad 60 Great Miami River, drowning of lower course ..... .. 66 Origin s.... y s. aan cda ries o a 58 Great Miami River valley, barrier to ice movement 43, 54 iflindian :. : ~. se 2. ou. comma ae reer 38, 43 pre-Illinoian Wisconsin .. Gunpowder Creek - .us. ar.. 34, 36, 61 Hamilton River . Harrison Lobe .. Harrods Creek .... : 88, 88, 86 Highland Rim peneplain . .. ..... :..... .fi 11 High-level fluviatile deposits, Irvine .... .. 20, 21 near Alton Ry a on. anu neil un ..20 Nebraskan .... preglatial . ).. 20. ...t re acin 11, 17, 20, 21 High-level valleys, Aftonian ........................ 36 preglacial. See Preglacial high-level valleys. Hog Trough Creek:. ...s .%... oes. ee Pir. d 41 I fee lobes, Clermont :.; :... isk. . sail y. P 42, 51, 56 Harrison 2000002, .. noha vene 43 iilinglan . sues. cree chy oo ove dh rb : 42 Jackson 7.30. 20. . 42, 49, 50 Miginis... .s ... . css iyo no ave ais mean ni er s 58 White 0... o. ors rocks ne s 58 Wigcon8if a 03-0. av a ceart dots reared dans o 58 Ice sheets, Labradoran dispersal center ............. 29 successive diversion ..... 2s ... , 39 Ice tongues, Great Miami River valley . t, .; 48, $4 Binolan «. .... 3 .. oes. . 42, 43, 49 Licking River valley -.. ...... .. u siar. Prions 54 Mill:Creek valley ...... :.... sio o bron 58 Ohio River valley, age determination ........... 49 conflict with melt-water drainage .......... 56 distribataries :. 02.0200; 20000... .. 48 downvalley limit ........... . 48 duration . s. cua. i33 . t ccie ..56 field evideri¢e s.. . .s -R. vee. m. ts. itor oo 55 Origin -. rola radials . xs edes Put Pd 54 Wisconsin .. ) . c bis. s . comedia r ioe 58 Illincian drift, boundary with Kansan in Indiana . .. .49 Carrollton; Ky .:. 2. 000], Luv s avea tasted r 48 distinguishing features. .. 9. .l no 42 expoBure® s. 2 90200 toe u. . A ca vane or sc 43, 48 sects 2s co 0 02 caca as sn a Pree vie 39 in bedrock Ohio River valley ............... 43, 48 Indiatia mess s. ao ce ears Ae tdr . 37 Kentucky .. 42, 54 southern boundary .. . /s. .. .... iO hic a 23 topographic expression .. ................... 43, 57 weathering as. uses ult y. o. din Ivie oo. o 57 Illinoian ice sheet, configuration .................... 42 invasion of Cincinnati area..................... 54 maximum advance ...... . 54, 56 Interglacial times, Aftonian ........ . #8 most important . 2. 40 ae... s clei ns ola ne ea raray deine, 56 stream degradation versus aggradation ......... Al Yarmouth . .s a 52s stat Pecs olo. name oe ione 40 J, K Jackson dobe .sis. cual. 2. ole . Toan 42, 49, 50 Jessamine dome ...; ., 2.0. sl. ines oo oer cie T, 9 Kame terrace ..; .. on tA sa aar o 48, 56 Kansan drift, Airport sections ...................... 28 boulders - s..2 02; ..- ti ir: . 24, 85 boundary with Illinoian in Indiana ............. 49 differentiation from Nebraskan drift............ 23 -% .... . . oo. . .. ea ern Pav 34, 38 +- meres . . son . cn on n en tesa cies 35, 38 in VaHey$ s/l ol 2s ame ero ce. , .. aoe sag 34 Indiana : 22 se sy ols reais fey : t rete aa wald 38 Kentucky uplands ............ . 22, 35, 36 on bedrock bench in Ohio valley ............ 34, 36 Pleasant Valley section .... :.... .. 202 28 INDEX Kansan drift-Continued relation to Nebraskan drift .................... 38 Scottsburg section ........... . 35, 36 southern boundary ::. css. ioe iy 23 topographic expression 34 weathering 12.3 AEL. L2. Nouns 28, 40 west boundary a 2. - 529.1... CIV Liv ren aree ao dg 37 Kansan ice sheet, maximum advance ... ... 85, 89 Kentucky River, abandoned meanders .. 41, 48 lacustsine terraces ar: d 61 preglacial. ris: sin enn ae 40, 41, 49 pre-lilinolan history : ..... coon cae t m 49 present course - ..o fos mova 2 L 2. 40 Kentucky uplands, evidence for two pre- Illinoian glaciations ................... 26 filinolan Ite extent -. nn .o a 54 Kansan drift ...... . 22, 35, 36 Nebraskan drife.......;....... .. - #2, 26 pre-lllinolan time .:....) 04; . 03 0s reran 51 stratigraphic sections f 28 Knobstone-Muldraugh Hill escarpment ..... ..... 10, 19 barrier to ice movement ................... 35, 37 overriding by Nebraskan ice ................... 24 passageways, Kansan .................. .. 40 Muscatatuck-East Fork White River . .. .40 Nebraskan Thore ve tas . 32, 33 preglacial -.. /s s 2s. oo dws. in ied 19 Salt River gorge ...;...... i...... 32, 33, 40 L Lacustrine deposits, fossils .. . 61, 64 iifinolan ... .: . ..565 RANSRI . +5 ., 4 2% ne 24 6+ Pea Praia n ern dea P 39 Nebraskan . (3.50 Lee rire ths sah a naw ae 25 Patewell . . 3 . . os) su on) tute Pia ma s aie ae 61, T0 Wistongin ... ! -... m ne an niet ave 61 Laughery escarpment ...;... 2.2 9, 10, 16 Lexington peneplain .; . maa 11, 20 Licking River, drowning of lower course . ..66 pre-ilinglan .> 51 Licking River valley, barrier to ice movement ...... .. .43 feestOhn@ue #. . : 31 Bled al re nairs + Pce 54 Iacustrine Lerraces 2 m. . c+. ad 61 Little Kentucky River . .61 Little Miami River ........... .66 Little Sugar Creek ........... 48 Loess, Cary 21. $s c noter, cs erin actuate s aan cad 65 differentiation from Kansan silttil .............. 36 Farmdale . s 22% ... 24 meted inn daven a de ravi s canes a 59 Illinoian .. Peorian ...... : pre-Takewell 3.30001 2. .59 Long Lick-Creek ... cr.. 48 Long RHD Walley .: -:-. . 5o : ane a in Wide haaa 64 M MceCools Creek ...;. .0. :... . =t daren aar haan s 17 Madison divide, Kansan ............ Laughery escarpment...................... 10, 16 Nebraskan 04202212020 0+ e Pue 31 preglacial ... ... 14, 16, 21 Yarmouth :s . 028 (coves . an iden neden ro a 42 Manchester divide, Nebraskan . ..30 permanent breaching. .... ...... .s ie ie 31 preglacial . . s. cray oo ready dh wee 13, 14 Manchester River :~. . . .o. ol es . 13, 34 Meanders, abandoned. See Preglacial high- level valleys. effect on till preservation ...... ,. !.... 43 Kentucky River .......... Quaternary -.. ..: .us 1 .t oan soe ane 41 Misinilobe s. . 1s :, 21 42.2300 y.. ane evade 58 Middle Creek... . . uk. irt. lias ao wale 36, 48 Middle Creek conglomerate .................... 36, 37 Mill:Creek . ; 2.10. .. 55758 Millport KitGbs . .. .... .s. 090. .o iss lay . sues sedans. d 50 Moraines, Illinoian ................. .37, 42, 49, 50 Wiscongin .sis, .of earl re se as 0 58 Muddy Creek. 2.1.5 222. 22s s. .oo saves rs oal 52 Mudlick Creek -. 2 =: 2212200201 ies nah ave en 18 Page Muldraugh Hill. See Knobstone-Muldraugh Hill escarpment. Muscatatuck regional slope ..................... 10, 12 Kansan Tee Sheet . .. ..o .c. cis ne n ad a od 35 Nebraskan tiH exposure ........................ 26 ONgin : sauce 2 dre ches in Parana neon bran 19 ills Ss S2 s .o 2 NLT 22 oo dora dan a 24 N, 0 Nashville dome .. aoe: rre. eee ial noen 7 Nebraskan drift, differentiation from Kansan drift ..23 exposures .... .» 28, 26, 29, 84 first evidence . s, 00 serre e eal e cde Lian s 22 indiafia .~. /.. 30. . aft? 68 Kentucky uplands ........... 22, 26 Pleasant Valley section .................... 28, 33 relation to Kansan drift ................. 38 Scottsburg section ......... 35, 36 southeast Indiana uplands ... ..85 southern boundary ........ ; 0g stratigraphic sections :... 24, 36 Weathering .s . .. ln 223. oe: read dogs. a 23 Nebraskan ice sheet, maximum advance . 20, 32 Norman upland 2308.1 5500s zee £200 fete cta aeon 10 North Bend-Cleves passageway . 52, 55 Norwood ARRIVE . . . ) -\ 2. farsa bs ac rre ess ao an r 13 Norwood troughs.... "12222 . L rhe re vii d 13, 55 Osgood section ...r. slau riod rile. alee: re 25, 33 Outwash, Cary ... ) a+: :~ + .. mak s be ren ei bad neath aad 56 intermixed with drift . 48 Kensan............ .36 Tazewell ........... .59 Outwash plain, Kansan . :.. .. .....2. 23: ove calc. .o 27 P Palit -Oregk .. :: .s. 2%. .. lls reran s nadie 18 Parker strath .... ..}... Pest. . som oii aoi : Peneplaing . .. .. SCAR Luce cises e reer, 11 Peorian Log#s ..... .. ime? avin cisa n. ras n d 50 Phillips Branch :.: 13.3. ..... . c . vedas 34, 36 Physiography .......... Pleasant Valley section ... Pleasure Ridge Park, Ky ................. Preglacial .-. A202 22 1 Soy + awan s nba be 11 Bivegrass region .... ).... 00s (ae aeons nee 13 Cincinnal area. > 12%. y. svar els prairie Pay. 18, 58 divides, ...: /v. . 2. cdr nass rans 1} Dayton :. ...>... 14, 16, 19 Madison .. 14, 16, 21 Manchester s. 022.22. sat 13, 14 glacial modification -...2.. ./vs, oul l+ lila ol 29 Muscatatuck regional slope ..................... 19 reversed flows ...s. . %.. our ie tain. us 13, 15, 18 Salt River system .. .. . i000 ise aa rene 19 symmetry of 0a 19 Teays-Mahomet River system . . A8, 21 upland surfaces ... cirri ass. » na sr dae 11 upper Ohio River valley ..........2....22...0 8, 18 Whitewater-Anderson valley ................... 16 Preglacial high-level valleys, Alton channel...... .. 20 between Gunpowder and Woolper Creeks ...... 36 Easterday channel ................ +11, 18, 20 Great Miami River. . 200... isan ade. 13 Kentucky River .... . . 02 c 17, 20, 41 Kentucky uplands .. . . ...... am nlra vats 81 Manchester River ... ; := 22... " 92. lpn naive,. 13 near Dayton, Ohio .. ; 12200 s) rear s ar an a 19 Ohio River ........ 3, 17 Wildest meander .;,. 0.3 .% +. 20 Preglacial streams, Anderson Valley ..... ... .. 18, 16 CADMANG .. , +2000 20000. daira rhe 3a a 9 15, 20 Cincinnati Rivers.. sa pols tela. ,us 18, 30, 58 Bast Fork of White River ..}.,.. ...... 19 Hamilton River ..... 2018, 14 Kentucky River ... . 40, 41, 49 Laughery Orde . . . 31 22.200 eee i nece vicars 25 May net ire olen real me al e oe a e ia as w h qe ott ot ¥ o te / Tan- - oa tulle ccs " ans PSR: A o . aloes 19, 20, 34 Salt @prings ci ar inate samara s s a+ 70 Sand dunes c ano. a nys BD d sels c SLE . + o fork ann a ae 60 Sangamon interglacial time 56 Scenic features; origin ... 1a +g 41 Seottsbure lowland :.. /s... 10, 19, 69 Scottsburg section so ..... ..... lines s 35, 36 : 1: 7:20 22, » T6. 2 22 ola cos ve s ails a 34 Soll, Cincinnati series. .... ..... A22 cua cies s in 24 White depsidized .. . :. ...... 00 mews n be 57 Split Rock conglomerate ... .............. 37, 48, 54, 56 Steele Bottom .......... vB Stephens Creek ............. $. eval sit bens read 18 Stratigraphic sections, Airport ................. 26, 34 Dabney. 2.0 .s colle ill, ev oral ay dere nat 25, 33 Dearborn uplafid . :s2.. 0. : 2 acl denn oir 24 Kentucky uplands . )2. .o... cu a rar cree 28 Muscatatuck State School ... ............... 24, 86 - Osgood s.. 2; series. V di 2+ s orf hea 25, 33 Pleasant Valley .. 2.0. allan a 28, 33 Scott County Stone Co. quarry ............ { 25, 85 . . :. .s 1 .a . ces cough ona 35, 36 Spillway . . as |.. s soa s nova 9 24, 35 See also Exposures. Stream aggradation ...;... 200.4 .... ... raugire , > 58, 69 Stream capture, above Manchester divide ........... 31 INDEX Page Stream capture-Continued Big Clifty Cree: .2.........2.22.ln can inal. + 41 Fogle sss s no rin ien rarer idan l 32 Nebraskan ss cues oo ST - saite eva «en's 31, 32 preglacial .; . .. al 15, 20 Salt River s . sc. 83 2.1. .r oer 's oa ored l a 20 Stream degradation ...-. 24.223. 42, 58, 65 Structural geology.. . .s... nl lla da sao na rane T Sugar Cfegik. : ...... . Sav. non defads ana nes 48 ¢ TTampiéo Ridge .. . 0 ions vende 37, 50 Taylor Creek :. .. . . .%. .s. 200600 omen a a re vaan + a 53 Teays-Mahomet River system ............... 13, 21, 30 Terraces, Gary lous citi cin nach vane 64, 66 comparison of Tazewell and Cary slopes ...... .. 64 correlation with ice advances ..................« 58 gCOROMIC YaIHQ ... .2 2. .. 1 nul pees ce bes oh 2 ae rears a 60 highdevel~ 21m ". 3a. orous tl bers ands 56, 58 -- 3 0200 000 c die taon ao vick a ou ne 38, 56 Kame re 2, Piss ilu cans nen be ae ie sa 48, 56 lacustrine deposits: . . ...... loves corr 61, 70 ow-levels sans. yo tac nis. 64, 70, 71 post-Tasewell 64, 70, 71 slope of surface .oo ns 59, 64 Tazewell: s a.. Lavena ref rien dak 58, 70, T1 Whitewater River basin 000 38 Wisconelty ... .. .s sol iF v2 sa cons coe ces 58 Till. See Drift. Topography, bedrock control ... ................> 9, 28 Blusgrass region ..... ieri ues 9 effect on ice advance ...................... 39, 42 @lacial control : :.}. . .s Ys mended reali ss rar 57, 58 Tlinolan Ofift .. : . :.. Sree neice cic lan 43, 57 Kansan drift .~: /s in/ 200020 2. an tey ral 34 Narmouth: +7. hocks iY ags e ele rac an cane ale 42 Tributaries, barbed . . .. ) cu. 17, 18, 52 L0 Ohio River... v is.. sao uks .+ Birk rex 64 oras ane 4 Twelvemile Oreek : s.,. .... «oie nd cial cen sage 8 54 U, V Underflt stfearms ) .. . ..., re aneedr derren d rec as 53, 55 Uplands, Aftonian dissection .... ..............> 33, 34 .+... 2. soca let- ofre . n o 11 Bluegrass region .... loove rica rei anar +08 s 9 Cheviok prong ... iss 2.0 .si ie. cai fe weg cha aren ag 51 Dearbo®n .are soca onl I bered her be ag a 9, 24, 42 Lexington perieplain ...... 11, 20 Norman:. . five snit as c irene lar. o na tke ade 10 Ti Page Uplands-Continued northern Kentucky. See Kentucky uplands. poor drainage ...... 0... sno l noes 33, 40 southeast Indiana sollg> .... . 24 Walnut Hills prong . .-. A.... .... 00. Loons ses ree 51 Uplift sss sore. core ce ne cares . ie » el 11, 34 Valley trains, correlative lacustrine terraces ...... ... 61 deflation; .... . .... . sn 59 Diinolgn :s sare ue. Kangas. s pre-Tazewell ...... Tarewell es.. ... Wisconsin _s. . .s 20 olo. re ils Or +9 +s ae 58 w, Y Wabash River .... 5... ool rey aia es oan s ri 56 Walnut Hills prong: -. 0. . ... Suzie in.i nay rake 51, 52 Waterfalls to .s .). . ange aln is ca died Prey anl aand 41 Weathering: Aftoniah _. .s 120220. 208. yalls site 1 oon 33 depth of leaching as age indicator ...... ... 23, 50 effect of good drainage .. .......: 224.2222 34 effect of poor drainage .... ...:: .s oar. d 57 gumbotil t.. Arnie r eae ades a apie d 33, 40 drift - 22.3000 t e aa 0+ ca) h 200+ ree a 57 Reansan drift - 2. da sau nls. ace roadie 28, 40 Nebragkan drift . 172.2 00; 94. 0000 vea sa raven +P 28 post-Tazewell deposits .... e+e +# 64 pre-ilinoiat (il.... .@. ... esl. Sangamon ..... Tazewell deposits . . white deoxidized surficial layer ..... .... Yarmouth ..:.. ...a 01. range. c. White River lobe . MWihites Rut 2... .... iss c. occa vara r iran ar easier + 17 Whitewater River .. .. 00..0 0 duane cian 15, 16, 54 Whitewater River basin, age of drift.......... ..38 MWiliow Branch.. . > .. .. .; ..o onl o dedi s rams 54 Wind deflation ass s.. 1.4 us . . . oe B a hat alte a+ a 59 Wisconsin drift, distinguishing features ... i208 relation to topography ...... ...... southern boundary .............. Wisconsin ice sheet, Cary advance .... garliest advance fiectuations .... .s. , . maximum advance 622.000 58 post-Cary history - .. .s) ... nace eae . s B 65 prefTazewell history ... 2000.0 59 Woolper Creck L... ... . (94 na nes 37, 48, 56 Yarmouth interglacial time ..................}. 38, 40 # U.S. GOVERNMENT PRINTING OFFICE: 1974-677-303/3 UNITED STATES DEPARTMENT OF THE INTERIOR PROFESSIONAL PAPER 826 PLATE 1 GEOLOGICAL SURVEY 85 l FAYETTE | ___| | 1 s/ i l * Rushville S/ l U F U s H | 1 ' S H E L B Y Shelbyville ® ___ JOHNSON 1 ? I DEARBORN }. Lawrenceburg xe Auror Petersburgj’x et p 3&ny ts Burlington® N Vernan ,, I ( 7 B U T L _E R //\/\{\\/\\’\ @ HAMILTON way semevome * Smeets ay 1 COVINGTO 5 \ $ J ENN INGS f-: I r-- I t r---4 . E KdS NY "f --- -Y} EF F E R S O N I RL AND Florence -# \& Madison 38 S PE NC FR f ANDERSON / 86 85 Base from U.S. Geological Survey 1:500,000 State base maps of Indiana, Kentucky, and Ohio EXPLANATION | [ 3] Drift of Wisconsin age Drift of ian age Darker color indicates terminal moraines of Jackson County, Indiana, and till and kame-terrace deposits along Ohio River valley Drift of Kansan age cag Drift of Nebraskan age Boundary Determined in part by field reconnaissance and modified in part from Leverett, 1929; Jillson, 1929; Wayne, 1958; Goldthwait and others, 1961; Durrell, 1961 10 20 MILES 1 Heal - ] 10 20 KILOMETERS o -- 06 GENERALIZED SKETCH MAP OF GLACIAL DEPOSITS IN THE OHIO RIVER VALLEY AREA PROFESSIONAL PAPER 826 PLATE 2 UNITED STATES DEPARTMENT OF THE INTERIOR GEOLOGICAL SURVEY 3 SP es so" . . 85°22'30 39°05 5 3 - i 7 tey - xg - 39°05 85°27 30" Tas | f E T <% > T 38°47 30" 38°47'30" |- R WILSON // HOSPITAL I a L-. o VILAEEFE PARLS\ § 7 C 2700 \ a ZZWG Memorial Sch vt 3, L] ~ CLIFTY FALLS ($ 38°45 ps _> a a | g y Fairgqounds | | | == | Moffett | Cem Milton: \ (23h 39000: '~\ Bm 8892 84°52'30" 4... fé LP Base from U. S. Geological Survey .. Lawrenceburg, Ky.-Ind.-Ohio, "< , * 1961, 7%-minute Quadrangle ¢ + xi?“ Note: The weli-known valley cutoff east and southeast of Petersburg. Glacial deposits of Illinoian age, s including the famous "Split Rock conglomerate" cliffs, are present within the river valley above and 85° 22'30" below the mouth of Woolper Creek. Tills and glaciofluvial outwash deposits, rise from river level to an altitude of near 600 ft C. GLACIATED OHIO RIVER VALLEY IN WESTERN BOONE COUNTY, KENTUCKY Ba.se {NET} y SA Gigagicaldsltl/Irvdey Note: Former channel of Big Clifty Creek northwest of the Devils Backbone and the many waterfalls, Sy is 19" a ’7im Ages particularly those along Big Clifty Creek. The narrow V-shaped valleys are cut into the upland flats W685, Kyi—Ind‘, (oi eit of the Muscatatuck regional slope quadrangles A. OHIO RIVER GORGE AT MADISON, INDIANA 85° 10° 85°07 30" o o [County MemofigH =! Hospital / ¢ (Field- - INTC J P \is ulna } 422, § % x { ( x s SCALE 1:24 000 1 Ya 0 1 s 0 1 KILOMETER E- -E- - CONTOUR INTERVAL 10 FEET DATUM IS MEAN SEA LEVEL MILE Cas 38°40 \ NM [i Landing ~ s \l i \\Strip W I Cina. x-) es TOPOGRAPHIC MAPS OF THE OHIO RIVER VALLEY, INDIANA AND KENTUCKY 85°07 30" 85° 10° Base from U. S. Geological Survey Carrollton, Ky.-Ind., 1967, and Note: Breached south wall of Ohio valley separates the Ohio River from an abandoned meander of the Vevay South, Ind.-Ky., 1967 Kentucky River that is now choked with drift of Illinoian age. Prominent lacustrine terrace flat of Wisconsin age is present at 490 ft in lower Kentucky River valley and in abandoned meander 7/-minute quadrangles B. OHIO AND KENTUCKY RIVER VALLEYS NEAR CARROLLTON, KENTUCKY