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Oakeshott, Gordon B.

Geology of the Coyote
Peak district of Plumas

County

| 1928

 
 

BIBLIOGRAPHIC RECORD TARGET

University of California at Berkeley Library
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040

GLADIS NUMBER: 184785336D FORMAT : BK AD:991006/FZB
LEVEL:Db BLT:am DCF:a CSC:d MOD: EL:7 UD:030604 /MAP
CP: cau L:eng INT: GPC: B10: FIC: CON: ARCV:
PC:s PD:1928/ REP: CPI: FSI: TI.C: IT:0
CUScCU

090
100
245

260
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502
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690

0

SbDISS.OAKESHOTT.MINING 1928

Oakeshott, Gordon B.,$d1904-

Geology of the Coyote Peak district of Plumas county /$clbylGordon B.
Oakeshott.

$c1928.

[11], 40. p. :$bill., map ;SC29 cm.

Thesis (B.S. in Mining) --University of California, Berkeley, May,
1928.

University of California, Berkeley.$bDept. of Mining
Engineering$xDissertations.

Dissertations, Academic$xUCB$xMining Engineering$y1928.

Microfilmed by University of California Library Photographic Service,
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Geology of the
Coyote Peak District

 

of Plumas County

 

LIBRARY COPY i

May 1, 1928 ~ Gordon B. Qakeshoti

 
Table of Contents

 

Section Page
I. IntroductioNeesesssssessssvscesssssssssscssnns 1
Physical ConditionSsesesssscsecsesscsscssseee 3
GBOLlOEYssessssssscessesssssscovsosvcvscsscses b
le Troncap FormatioN.sesecssessssecssssce 5
2, lMeta=andesit@sssscvosssoscssnsesssseesll
Contact Facies of Meta-andesite.....l6
Be ApPlit@ecscsssssssssessssscscssscscsanel8
4, Bngels Diorite...ssessessssscssscssees20
5 Superior Granodiorit@.cscecccscsescess2éd
6s Auriferous GravelSesecssssescssscscscselB
7¢ Bear Creek Arkos@ecsscccsssssscssossesld
8s (Coyote Peak Rhyolite and Andesite,,,..30
Metalliferous Deposits and ProspectS.e.sses..3l
le Gold, Quartz Veins and Placerse.s.csss.31
2, Copper ProspectScssesscssecscsssssasssdl
Copper King ClaimBessececsescsscsss edd

Vendome ClaimBessessssscsecsssensessdd

Bull of the Woods ClaimBeccerscesseedéd

Miriam and Alma CleaimSccseceseccccceedd
Troncap ClaimSesssssccccsssseesersssdd
Uncle Sam ClaimSesscsccccsscssensessdd
Cuperite Claims...eceveessssssencseedd
Manzanita, Arrowhead and Coyote

ClaimBesessssesroessvsssssssesasedB

 
 

Plate

 

I.

II.

III.

List of Illustrations

View of the Coyote Peak District

from the Sulphide ClaimBesesecssescssvcnscneedT

Lights Creek Valley near the Burnt Cabin..s....38

Figure 1.

Figure 2.

Figure 3.

Figure 4.

Figure l.

Figure 2.

Figure 3.

Figure 4,

Outcrops of Superior

Granodiorite, Bear Creekesscecss39
Sandstone Bluffs on

Troneap FH#6esssssssssessssesssssssesdd
Sandstone Bluffs as Seen

Across Bear Creek Valleyeesosesse39

Bear Creek ArkoSOsssecscsccccccssesdd

Qutorops of Arkose South of

Trono&p F#1l6eeescsssssscsssssscessdl
Arkose Overlying the

Auriferous GravelSsseccssessossscdl
Red Gravels Underlying
ArkoB@.sssssesocssccssssssssnssesdl
Hydraulicked Gravels on the

West Branchesescccscsssecessscssesdl

 
 

Geology of the Coyote Peak

 

District of Plumas County

 

Ie Introduction

Coyote Peak lies in the southeastern part of Lassen
County and within a few hundred feet of the northern border
of Plumas County. It rises to a height of 7300 feet, topping
the neighboring mountains by only a few hundred feet. The
area covered by the survey extends south about four and a half
miles and southeast about four miles. It is bounded on the
south and southeast by Lights Creek and its branches and comes
to a focus on the north of Coyote Peak. It is covered by a
number of unpatented and unsurveyed claims, of various locators,
located in Township 28 N Range 10 E Sections 25, 24 and 13 and
in Township 28 N Range 11 E Sections 31, 30, 19, 18, 32, 29,
20, 33 and 28. This group of claims lies immediately north
of a block of sixty-seven patented claims, a few of which
appear in the southeast corner of the map, belonging to the
Engels Copper Mining Company which is now operating two copper
mines on the group.

The purpose of this investigation was primarily to gain

more accurate information concerning surface indications of

copper than that given by the rough prospector's map now avail=-

 
able and to map the various formations, investigating most
thoroughly those more likely to show copper mineralization.

The map used as a base for plotting the geology is a
prospector's map made by He O. Thiem, locator of many of the
claims. The claims were located by Brunton compass, with a
fair degree of accuracy, and streams, roads and trails evident=- .
ly drawn in by estimation, in many cases being erroneously
located. While mapping the geology a few additions and
corrections to the original map were made by the Brunton
compass where practicable and necessary. The mapped geology
has been located with reference to claim corners wherever
possible, supplemented by streams and trails where the mapped
claims did not extend.

The method followed in the field was first to make

a preliminary trip over a portion of the area to determine

the formations present, rock types, and copper indications

as shown in surface outorops, and in cuts, discovery holes

and tunnels made by the claim locators. This was followed
by a second trip in which the geology was mapped, the contacts
being located with reference to the claim corners by Brunton
compass and estimated distances. The time spent on the whole
area was approximately twenty-five working days. The entire

work was done in company with Mr. Joe Quigley, a prospector,

 
 

C

 

whose knowledge of the country and its history as a mining
district was of great assistance in preliminary reconnaissance

and in location while mapping.

 

II. Physical Conditions

The Coyote Peak area is on the western slope of the
Sierra Nevada in a rugged, mountainous country at elevations
varying from 4300 feet to T7300 feet, The new sawmill is
located at the junction of the East Branch of Lights Creek
with the main creek at an elevation of about 4500 feet.
The valley of Lights Creek at this point is at its widest,
about 500 yards, the mountains rising abruptly on each side,
The mountains rise higher toward the north, culminating in a
ridge, of which Coyote Peak is the highest point, at an
elevation of about 7300 feet. A prominent ridge runs up the
center of the vendome group of claims from the old Tunnel and
Millsite. The rest of the country is very irregular and
rugged, rising from Lights Creek to Coyote Peak and cut by
many small streams. Approximate elevations shown on the
accompanying map were estimated from a few known elevations in
the vicinity. The known elevations were teken from prospector!s
maps and from the U. 8. G. 8S. topographic map of the Honey Lake

Quadrangle.

 
 

Lights Creek is the largest stream in the vicinity and,

with its two main branches, the only one flowing all year
round, All other streams drain eventually into Lights Creek
and flow only during part of the year when the snow is melt-
ing. Moonlight Creek and the West Branch are unusual in that
they have the same source, flow in opposite directions from
that source and both empty into the same creek. Melting
snows, which accumulate to considerable thickness in a

saddle near Shake cabin, are the source of both streams. West
Branch flows west from Shake cabin and swings around in a narrow
valley to the north and finally east flowing into Lights Creek
on Bull of the Woods #3. Moonlight Creek flows due east from
Shake cabin to Lights Creek a quarter mile below the new saw=
mill, Lights Creek flows into Indian Creek which is one of
the small tributaries of the Feather River.

The climate is what might be expected as a result of the
elevation and situation on the western slopes of the Sierra.
Snowfall is heavy in the winter and snow remains in patches
above 5000 feet elevation until after the first of June. In
the cooler summers it sometimes remains all year on the northern

side of Coyote Peak. The summers are warm in the daytime but

cool at night as is typical of mountainous regions.

 
   
  
  
  
  
  
    
  
   
    
  
   
  
   
    
   
   
     
     

The area is heavily timbered with yellow pine, sugar
pine, spruce, Douglas fir, white fir and cedar; the best
timber being below elevations of 6000 feet. Above 6000 feet
the timber gets smaller and poorer. Coyote Peak for the
last 800 feet has only a few small pines on it. Occasionally,
open spots in the woods are covered with a dense growth of
various kinds of brush. The Manzanita claims at about the
timberline on the southeast slopes of Coyote Peak are densely
covered with manzanita brush, making the largest spot free from

timber in the region.

r III. Geology
{ -

1, [Troncap Formation

The Troncap formation is found in only one place in the
district. It extends for a little less than a mile, about 600
feet wide, along the northern end lines of the Troncap group of
claims west of Williams cabin.

A small narrow canyon extends west from Williams cabin
up the center of the formation exposing it along its course.
The stream has its source near the west end of Troncap #13.
The formation at that point extends across a low saddle in a ridge
which separates the small canyon from the deep, narrow valley of

Bear Creek. Bear Creek has cut a rather deep valley, on the

   
 

 

 

northern side of which are the grey sandstone cliffs of the
Troncap formation. The hills rise steeply on each side of
the valley.

The rock as seen in the hand specimen is very fine
grained, containing a large amount of quartz and considerable
calcite. It varies in color from pure white to grey, pink,
reddish or pale brown. It is commonly massive but some bedd=-
ing could be seen on Troncap #6.

Near the tunnel on the north end line of Troncap #10
the rock was pure white in color and appeared to be a limestone
containing a little quartz. On the hillside sloping steeply
up from the creek south of the tunnel, the rock is leached and
stained to bright reds and yellows by iron oxides with a trace
of green malachite stain. The tunnel extends for only about
fifteen feet into the formation but it exposes it well. The
rock contains a considerable amount of pyrite with a few specks
of chalcopyrite. A small amount of sulfur and a pale greenish
mineral occur as encrustations on roof and walls, |

Under the microscope the rock from the tunnel was seen
to consist essentially of quartz, calcite and an unusual mineral
which after examination of several thin sections was recognized
as alunite. Quartz formed about fifty percent of the rock,

occurring in small anhedral grains of various sizes but all less

 
  

  

than one-tenth millimeter in diameter, often in masses with a
fine grained mozaic texture. Calcite occurred as an irregular
filling between quartz grains, amounting to about thirty-five
percent, The alunite, amounting to about ten percent, was
commonly in enhedral grains throughout the section although
enhedral grains were not uncommon. The mineral was in colore
less squares, rectangles and hexagons with an index of refracte
ion somewhat higher than quartz and birefringence slightly
higher. Extinction was parallel or symmetrical. The mineral
was uniaxial and optically positive. A perfect basal cleavage
was characteristic and from its form the mineral clearly
belonged to the hexagonal system. As a check on the optical
properties, which strongly suggested alunite, tests were made
on the rock for sulfate and aluminum. Both tests gave clear,
positive results. In addition to quartz and alunite minor
amounts of pyrite and chalcopyrite were present. 2ircon and
apatite, in very minute erystals, were present. A small amount
of deep blue=grey tourmaline occurred in a group of radiating
prisms, Two small fragments of badly altered plagioclase seen
in this section was the only trace of feldspar in any of the
several sections of the Troncap formation which were examined.
On Troncap #6 the rock was essentially a very fine grained

sandstone of various shades of grey, brown or pink. The forma=

 

 
 

tion in this region has formed steep cliffs extending for 500
or 600 feet. They rise to a height of seventy-five feet or
more on the north side of Bear Creek Valley. The rock has
weathered into large rounded humps and hollows, presenting an
appearance characteristic of massive formations of uniform
composition. Interbedded with the sandstone are seams of
nearly pure quartz and chert. Areas of quartz and chert are
common in the whole formation west of Troncap #13. In thin
section this phase of the formation was found to consist wholly
of quartz grains filled in with layers of chalcedony. The
quartz was commonly of a pinkish or brownish color, probably
due to hematite, as specular hematite in small flakes is a
prominent constituent of the rock. Masses of reddish bleck
specular hematite are common near the western end of the
formation on Troncep #2, #5 and #6. BEpidote is also a minor
constituent of the rock.

A section made of the sandstone on Troncep #6 consisted
of fifty percent quartz, forty-five percent alunite, three percent
miscovite and lesser amounts of hematite, apatite and zircon.

A section from Troncap #12, identical in the hand specimen with
the rock from Troncap #6, differs in having sixty percent alunite

and thirty-five percent quartz, The minor constituents were

 
 

C

as above. Small fracture lines in the rock filled with

quartz and alunite were not uncommon.

A few sections of the Troncap formation very close
to the Meta-andesite contact were made. They were alike in
containing no alunite and much larger amounts of muscovite
in the form of minute flakes of sericite. Hematite likewise
was more abundant; in one place on the contact forming about
forty percent of the rock. A section at the contact on Troncap
#12 contained twenty-five percent quartz, twenty percent zoisite,
fifty percent sericite and muscovite, a small percentage of
minute specks of red garnet and a little hematite.

In summary, it appears that the Troncap formation is a
sedimentary formation which has been altered by dynamic metaw
morphism and to a lesser extent by contact metamorphism, The
formation now consists of a fine grained sandstone, quartzite
and a little sandy limestone. The original bedding is present
in part of the formation. It seems likely that rhyolitic
tuffaceous material present in the original sandstone has given
rise to the alunite, which is an abundant constituent. Alunite
is a secondary mineral, found in acid volcanic rocks, formed by
hot sulfurous vapors and solutions acting on potash feldspar.
Its presence is therefore suggestive of the original character

of the sediments.

 
   

 

 

  

A certain amount of contact metamorphism was observed
along the contact with Meta-andesite. This was shown by ine
crease in hematite near the contact, by the development of
muscovite, zoisite and garnet and by the disappearance of
alunite at the contacts In view of the contact metamorphism
of the Troncap formation, Meta-andesite has been considered the

younger of the two.

2. lMeta=-andesite

The Meta=-andesite is the most widespread formation in
the Coyote Peak region, occurring in a broad area from Bear
Creek north nearly to Coyote Peak,

It is a dense, black rock with phenocrysts of plagioclase
varying in size from microscopic to an inch long. The ground=-
mass is commonly very fine grained and greenish~black to black
in color. [Epidote is extremely common as an alteration product
of the ferromagnesian minerals in the groundmass and also
occasionally of plagioclase, Rarely the Meta-andesite is
amygdaloidal but commonly is dense, The rock on the Copper
King and Vendome groups of claims was black with a dense micro=-
crystalline groundmess with phenocrysts of plagioclase varying
from an eighth to a quarter inch in length. North of Williams
cabin on the Miriam, Enos and Morse claims the rock was much
finer textured. The plagioclase phenocrysts, forming only a

small percentage of the rock, were almost microscopic in size

and the groundmass extremely dense and fine grained. This

 
finer textured Meta=-andesite contained less epidote, the
feldspars were fresher, and in general the rock showed less
metamorphism than the rest of the formation. A-thin section
from Vendome #15 showed it to be a meta=hornblende-andesite
with phenocrysts of andesine and hornblende. The phenocrysts,
one~half to one millimeter long, formed about fifty-five percent
of the rock, of which eighty-five percent was andesine and
fifteen percent hornblende. In this section the feldspar
showed little alteration except the development of some sericite
which did not obscure the twinning or zoning. Fine grained
quartz and actinolite were developed along fractures in the
feldspar and as alteration products of the groundmass. The
groundmass consisted of andesine, thirty-five percent, and a
fine grained aggregate of actinolite, quartz, biotite, and
magnetite, Actinolite, quartz and biotite were all secondary,
existing in fracture lines and as alteration products. Actinolite
was found to be a very common secondary mineral in all the basic
igneous rocks of the region. It occurred as fibrous blue-green,
strongly pleochroic anhedral crystals or as very fine grained,
irregular aggregates in many rocks.

A section of the Meta-andesite from the Uncle Sam claim

group was much more thoroughly altered than the above. The

feldspars were completely altered to a mass of fine grained

 
 

12

quartz and sericite obscuring all twinning and zoning. The
groundmass we.s thoroughly silicified.

On Uncle Sem #18 and #8 the rock showed its coarsest
texture. Large phenocrysts of plagioclase an inch long formed
over fifty percent of the rock, with a fine grained greenish-
black groundmass making up the balance. On the Uncle Sam
group of claims the rock was occasionally somewhat vesicular
with a small amount of malachite, chalcopyrite and bornite
filling the vesicles in some instances.

The Meta-andesite showed very little copper mineraliza-
tion but near the Uncle Sam cabin copper minerals were found
in specks through the rock. On Uncle Sam #3 the rock surface
was heavily iron stained and showed a little copper stain,

The tunnel on the creek was in several feet but no trace of
copper was found,

On Uncle Sam #10 near Bear Creek, the Meta-andesite had
a marked schistose structure showing plainly the effects of
crushing and folding. In the rest of the area this structure
did not appear, the feldspars commonly being little altered and
sometimes showing twinning.

On Bull of the Woods #1 a shaft has been sunk about
thirty feet into the Bull of the Woods Ledge. The ledge is
a quartz vein about twenty feet wide cutting the Meta-andesite

with a strike of N 30° B. The vein could only be followed in

 
the outcrops for about two hundred feet but probably extends
further. The outcrop near Williams cabin is iron and
carbonate stained. Just below the surface the rock consisted
of leached quartz high in iron oxides, malachite and azurite.
Small veins of grey chalcocite oxidizing to cuprite occur in
the quartz as well as chalcopyrite and bornite. Epidote and
actinolite also are present as vein minerals with quartz.
Another vein a pow feet wide, the Rhinemiller Ledge,
is on the Alma #1 to the north of Williams cabin. The vein
strikes about N 45° E and like the Bull of the Woods vein
can only be followed for two or three hundred feets The two
veins look as if they might connect to the northeast but they
do not show in the outcrops beyond the first few hundred feet.
A tunnel has been put in about a hundred feet to meet the
ledge on Miriam #1. A small amount of malachite and chalco='
pyrite was found at the portal of the tunnel. An incline
sixty feet deep has been sunk on Miriam #1 into the vein,

The vein material is essentially quartz, with limonite,

hematite and malachite showing on the surface. A few feet

down the quartz contains considerable chalcopyrite and bornite
with pyrite, epidote and actinolite as accessory vein minerals
in the quartz, The Meta-andesite wall rock also shows some

mineralization.

 
 

14

Tunnel B: on Vendome #15 above the old Millsite is in
a small quartz vein, There is an iron gossan on the surface
but no copper stain.

The age relation between the Meta-andesite and Engels
diorite is discussed in the section on the Engels formation.
The Meta-andesite is older than the diorite and therefore older
than the Superior granodiorite which is younger than Engels
diorite. Northeast of Vendome #8, Superior granédiorite has
cut off and metamorphosed the Meta-andesite. Near the Thiem
cabin on Cuperite ff11, #8 and #9 Superior granodiorite has
evidently intruded the Meta-andesite and on Troncap 11,
southwest of William®s cabin, Meta-andesite has been cut off
by Superior granodiorite. Superior granodiorite is therefore
clearly the younger of the two formations.

On the contact with the Troncap sandstone on Troncap #6
the sandstone is iron stained for a short distance and also
shows a slight malachite stain here and on the contact on
Trancap #13, Evidences of metamorphism of the Troncap forme
tion by Meta-andesite, described in the section on the Troncap
formation, show the Troncap formation to be the older of the two,

The Bear Creek Arkose, a rock horizontally bedded and
apparently unaltered, cuts off the Meta-andesite on Troncap #10

and clearly is a younger formation.

 
Although the time available and the purpose of the
investigation did not admit of a detailed study of the Meta-
andesites, they are probably intrusive. On the whole, the
rocks contain large phenocrysts and are not vesicular and
have a fine grained holocrystalline groundmass, Surface
flows, even if thick, would tend to show finer textures, a
finer grained to glassy groundmass and would be vesicular,
at least in part.

In general, throughout the area, the Meta-andesite
has formed prominent outerops. It evidently is more resistant
to weathering than any of the other formations. The ridge
extending up the center line of the Vendome claims from the
Tunnel and Millsite shows prominent outcrops of rock, sometimes
ten or twelve feet high. Near the old Tunnel and Millsite
on the north side of the creek a sixty percent slope has been
formed of loose angular pieces of broken Meta-andesite from

the prominent outcrops 300 or 400 feet above. The steepness

of slope, large amount of loose material and straight line of

the slope which follows along the creek about half a mile
strongly suggests that the creek at this place runs along a
fault. Unfortunately there are no outcrops of either the
Aplite or Meta-andesite along the creek and no displacement of

a contact could be found even if it exists.

 
 

 

  

Contact Facies of Meta-andesite

In some places near the contact with Engels diorite
the Meta-andesite appears to have been further metamorphosed.
The rock is very dense, fine grained and of a greenish-black
color making it difficult to determine in the hand specimen.
The most prominent mineral is epidote which occurs in masses
and veins in the rock. Very small grains of quartz, biotite
and minute plagioclase Soldupns crystals make up the distinguish=-
able minerals. From its composition and occurrence the rock
appears to have been derived from the Meta-andesite, largely
by contact metamorphism by the intrusives. In many places
near the contact with Engels diorite the rock might properly
be called a hornfels., Its contacts with Meta-andesite are
gradational, the rock gradually showing a porphyritic texture
and grading into Meta-andesite.

A thin section of the contact facies at Quigley Camp on
Copper King #5 was examined, The rock was a Meta-andesite
essentially the same as that described from Vendome #15 but it
showed more alteration and the development of a few new minerals.
The feldspars were largely altered to quartz and sericite,
chlorite was present as a secondary mineral in addition to
biotite and actinolite, and the feldspar of the groundmass was

unrecognizable. Deep blue-grey tourmaline was present, in

 
 

17

small amount, with a few large crystals of anhedral apatite
and epidote. Bornite and chalcopyrite, molded against the
other minerals were present in large enough amounts to give
the rock an assay of one and four~tenths percent copper.

A section of the sonnet facies of the Meta-andesite
from Copper King #12 was examined. This rock showed no
phenocrysts and in the hand specimen closely resembled that
from Quigley Camp. However, under the microscope it was
found to be similar in every way to the groundmass of the
normal Meta-andesite. It was evidently a local variation
of that formation in which no phenocrysts were developed.
In view of this occurrence, the actual contact facies of the
Meta-andesite may be of less extent than shown on the map.

The only copper mineralization of any extent in this

pars of the Meta=-andesite formation is found at Quigley Camp

at the contact with Engels diorite. Malachite and chrysocolla
oceur in small amounts in the outerop while bornite and chalco-
pyrite are found in the tunnel which has been put in for a few
feet. The bornite does not ocecur in specks all through the
rock but is in small irregular veins and masses, often with
elbite, feldspar and a little quartz.

The rook east of Copper King #8 is of slightly different

character. from that at Quigley Camp. It is less basic, forms

 
very poor outcrops and contains a high percentage of epidote.
No mineralization was found in that region but specks of chalcopyrite
are shown occasionally along the arm of the formation exposed along
Lights Creek below Quigley Camp,

The narrow strips of the facies east and northwest of
Vendome #8 and #10 show fair exposures along the contacts and
show its relation with Engels diorite. The diorite becomes finer
textured within a quarter inch of the contact, with a narrow strip
of epidote formed at the contact, The Engels diorite therefore
is evidently the younger of the two formations. Further evidence
of the age relationship is discussed in the section on the Engels

formation.

3. Aplite

The Aplite formation is found in a belt running from the

Sawmill northwest and southeast. It also occurs south of the
Vendome group and on Vendome #2 and #12, The rock characteristically
is white in color and very fine grained, It consists essentially
of quartz and feldspar with small amounts of a black mineral, with
a radiating orystal arrangement, which was found to betourmaline
under the microscope.

A microscopic determination of the rock proved it to be a
tourmaline aplite consisting of sixty percent quartz, twenty percent

orthoclase, five percent andesine, ten percent tourmaline and a

 
little magnetite. The tourmaline was in deep reddish-brown
anhedral orystals in masses in the rock. The feldspars showed
a little alteration to sericite and kaolinite.

Outerops of the formation are rare, due, undoubtedly, to
the ease with which the rock weathers. It forms a light color=-
ed grey soil which often was the only evidence of the underlying
formation. The Aplite on Vendome #2 and #12 showed no outcrops

but pieces of the rock in the soil indicated its presence. The

only cropping in the area of Aplite south of the Vendome group

was found in Davis Creek.

The contacts of the formation were very hard to follow
because of the ease of weathering of the rock and the lack of
outcrops. The area is thickly wooded and quite a thickness
of soil has formed over the formation. On this account the
age relationship of the Aplite was difficult to determine,
Engels diorite appears to intrude the formation on Bull of the
Woods #3 and east of the New Sawmill, making the Aplite the
older, but this relationship is uncertain, The aplite evident=-
ly cuts off Meta-andesite east of Davis cabin and is therefore
considered the younger of those two formations.

Near the New Sawmill, outcropping for only a few feet
along the Ruffa Ditch, a schistose rock was found closely
resembling the Aplite and in the field mapped as Aplite. The

attitude of the schistosity varied from strike N 30° W and dip

 
64° northeast to strike N 50° W and dip 74° northeast. A

thin section revealed it to be a metamorphosed sediment, It
was a cordierite sillimanite quartzite consisting of thirty-five
percent quartz, twenty percent cordierite, twenty-five percent
sillimanite, fifteen percent magnetite and a little apatite,
zircon and hornblende. It had evidently been derived by

contact metamorphism from a clay shale or fine textured sandy

clay by the Engels diorite intrusion with which it was in

contact. The exact extent of the formation is not known as the

only outcrops were for a few feet along the Ruffa Ditch.

4. Engels Diorite

The Engels diorite is the most widespread intrusion in
the region. The Engels Mine is located in the formation about
a mile and a half south of the U. 8. Ranger Station. The
intrusion extends east and southeast of the Coyote Peak group
of claims for several miles.

In its typical occurrence it is a medium grained quartz
diorite containing a high percentage of plagioclase, a little ortho=~
clase and a small amount of quartz, with hornblende and biotite
as the ferromagnesian constituents. It is characterized by a
considerable range in texture and mineral composition. As

studied in the Coyote Peak region the finer grained phase of the

 
 

 

21

Engels contained a high percentage of biotite as the femic
constituent and more quartz than the coarse grained Engels
diorite which carried hornblende crystals with little biotite.
Thin sections of the rock, two from Bull of the Woods #3
and one from Copper King #10, showed it to be a medium grained
hornblende diorite. It consisted of fifty percent labradorite,
forty percent hornblende and small amounts of magnetite, tourma=
line and biotite. The feldspar was strongly zoned, many
crystals grading from labradorite on the inside to acid
andesine on the outer rim, Sericitization and kaolinization
has taken place to some extent, A large proportion of the
original common brown hornblende has been altered to fibrous
actinolite. The small amount of blue grey tourmaline present
occurred in aggregates of anhedral crystals. Probably a
large proportion of the Engels formation is a true diorite
and not quartz diorite, although in some places quartz was found
to be present in small amounts,
The relation to Superior granodiorite as shown on the
West Branch and on Contact #5 and #6 is explained under the
discussion on the Superior formation. Apparently, Engels diorite
is younger than the Meta-andesite. It is in contact with Meta=-
andesite along the Copper King group and just east of the Vendome

group of claims. The Meta-andesite has been further metamorphos-
 

22

ed by the diorite in some places, as mentioned before. On
Copper King #7 the border zone of Engels diorite is very basic,
consisting mostly of large crystals of Bornblande end a little
plagioclase. In places along this contact the rock is a horn=
blendite, consisting only of crystals of hornblende a half inch
to an inch in length. Such a border zone would probably have
been obliterated if the Meta-andesites were younger. The
Engels formation has therefore been considered younger.

On Copper King #1 a quartz biotite schist has been develop-
ed along the donkaet a few feet in thickness. It consists
largely of biotite and quartz with a smell amount of plagioclase
feldspar. A similar schist occurs in a narrow zone along the
contact just north of Vendome #10. Its origin was not certain.

On Copper King #8, near the Superior, the Engels diorite
shows a somewhat gneissic structure. This was the only place
such a structure was found,

All along the Copper King group, the diorite was found
to contain occasional specks of chalcopyrite and bornite.

Pegmatites were found in some places in the Engels forma=-
tion. Along the creek east and north of Vendome #10 pegmatitic
rocks were found in several places. Rocks composed wholly of
erystals of orthoclase a half inch long with quartz and a little
muscovite were most common, quartz and orthoclase often occurring

together in graphic intergrowth. The most interesting occurrence

 
 

 

23

is probably in the Engels formation on Copper King #9. A

short tongue of diorite is in contact with Mete-andesite on

the south and north. The Engels is coarse grained, acid and
pegmatitic, appearing to grade gradually into normal Engels
diorite on the east, The rock contains a high percentage of
quartz and orthoclase with some chalcopyrite, pyrite and
bornite. Occurring in small irregular veins in what appear to
have been fractures are chalcopyrite, pyrite, bornite, epidote
and crystals of albite, muscovite, chlorite, orthoclase and
quartz. The rock also contains a large amount of black
tourmaline occurring not in veins but in irregular masses two

or three inches across with chalcopyrite and bornite, the tourma-
line crystals poorly developed and often radially arranged.

The character of the formation appears to have been the result
of pneumatolytic action; by hot mineralizing solutions and gases
which have invaded the rock, probably with the intrusion and
before solidification.

The weathering of the Engels diorite is quite different
from the Superior granodiorite. Jointing and angular blocks are
characteristic of the Superior while Engels diorite weathers
characteristically into rounded Lotus Exfoliation inte round=-
ed plates about a half inch thick is common in outcrops of the

Engels diorite. On the whole, exposures of Engels were better

 
 

2g

than those of Superior, the latter appearing to weather a

little more readily.

Se Superior Grenodiorite

The Superior Granodiorite is an intrusive which is
next in importance to the Engels. It is found not only in
this particular region but extends for about three miles south-
west of the New Sawmill along Lights Creek. The Superior
Mine of the Engels Copper Mining Company is located in Superior
granodiorite about three miles southwest of the sawmill. The
Yergesh mass in the Coyote Peak area is west of the sawmill,
extends north onto the Bull of the Woods claims and to the south
and southwest for two or three miles,

The rock shows some variation in composition although
the size of grain is rather uniform. Typically it is a fine
granodiorite, often with a pinkish cast due to pink orthoclase.
It consists essentially of plagioclase, orthoclase, quartz and a
small amount of hornblende. Often the rock is somewhat more
acid in character, containing a higher percentage of pink
orthoclase than plagioclase, more nearly approaching a fine grain-
ed granite. The Superior is uniformly finer grained than Engels
diorites

Under the microscope several sections examined from the

Bull of the Woods claims showed the rock to be a fine grained

 
 

25

 

quartz diorite, It consisted of forty percent acid andesine,
fifteen percent orthoclase, fifteen percent quartz, ten percent
biotite, ten percent common hornblende and small amounts of
magnetite and zircon. The rock ve very fine greined, all
crystals being less than one=~half millimeter in diameter. One
section showed a marked tendency to be porphyritic. The texture
was essentially granitic but the tendency of the andesine to be
enhedral strongly suggested the porphyritiec. Another section
in the same general region had the same composition and size of
grain but the texture was decidedly aplitic.

The formation outcrops very prominently along Lights
Creek and the West Branch as well as northeast of Vendome #8,
Where exposed to the weather in large outcrops the rock breaks
off in angular slabs forming steep slopes of loose broken rock.
Along Lights Creek these talus slopes are very noticeable in
places. The severity of the winters and the large temperature
range in summer days meskes disintegration rapid. Where the rock
has decomposed, the soil formed is of a reddish color and somewhat
clayey. Near the junction of the creeks on Bull of the Woods #3,
where the rock contains a high percentage of pink orthoclase,
the soil formed is distinetly reddish in color,

Due to the overburden of soil in the forest, the thick

brush in places, and often, scarcity of outcrops, it was difficult

 
 

26

to follow the contacts with other formations. Actual exposures
along the contact were rare. On Bull of the Woods #3, in the
creek, the contact with Engels diorite was exposed for a few
feet showing the age relation plainly. Stringers of Superior
granodiorite cut the Engels diorite showing the Superior to be
the younger. The contact was very sharp, with practically no
metamorphism. Superior granodiorite became slightly finer
grained toward the contact and a thin seam of epidote about an
eighth inch thick separated the two formations at the contact,
On Contact #6 the same relationship is shown, stringers of
Superior cutting into Engels with little or no metamorphism,

The intrusion just east of Vendome #8 cuts into the Engels, again
establishing Superior as the younger,

Epidote is extremely common as a product of metamorphism
and as a vein mineral with quartz, not only in the Superior
formation but in Engels diorite and Meta-andesite as well,
Epidote is common as an alteration product of the ferromagnesian
constituents,

Although the Superior Mine at Engels is located in Superior
granodiorite, copper showings in this formation in the Coyote
Peak area are negligible.

The small intrusion north of the Thiem cabin on Cuperite

#11 is more acid than the normal Superior granodiorite, containing

 
 

27

a high percentage of quartz, pink orthoclase, plagioclase

and a little hornblende altering to chlorite and epidote.
Outorops are somewhat leached, weathered and stained and ribbed
with black and brown veinlets of manganese and iron oxides.
Pyrite is present with chalcopyrite in traces. Also slight
stains of malachite show in the owtorops. The contact with
Meta-andesite is easily followed here and around the larger
intrusion to the east, the Meta-andesite forming prominent
outcrops while the granodiorite has weathered more readily
giving the characteristic reddish cast to the soil,

On the West Branch near the old Brickenal cabin gold
bearing gravels occurring lying on the Superior were hydraulicke
ed in early days. Hydraulic mining was carried on extensively
along the West Branch. Near Kennedy's cabin on the Moonlight
Valley road some copper occurs, in a silicious phase of the
Superior formation, in the form of malachite, chrysocolla and
a little chalcopyrite.

On Bull of the Woods Extension #1 the Superior does not
show the usual pink color but conteins more plagioclase, less
orthoclase and more hornblende making the rock a fine grained
quartz diorite. On the creek near the middle of the claim

it shows a small amount of pyrite with just a trace of chalco=

pyrite.

Superior granodiorite is also found just east of Copper

 
     
     
   
   
       
  
    
   
   
   
   
 
      
  
     
   
     
    
   

King #10 in contact with Engels diorite on the south and
Meta=-andesite on the northe The formation was only traced

as far as shown on the map but it actually extends for a con=
siderable distance to the east in contact with Engels diorite.
The old Severnman Diggings is an old placer which worked

auriferous gravels.

6. Auriferous Gravels
Auriferous gravels are found in several places, principally
at Sevenman Diggings east of Copper King #10, Davis Creek and in
a narrow belt extending from Davis Creek across to the West
Branch, along the West Branch and onto the Troncap claims.
They are auriferous and have been placered for gold all along
their extent.
The size of the gravel varies from boulders six or eight
inches in diameter to cobbles, coarse gravel and small pebbles.
Under the arkose on the North Fork of the West Branch, they con=
sist of pebbles of various sizes loosely cemented with tuff and

The gravels consist of

   

a large amount of deep red iron oxide.
material derived from older formations and in general are well

rounded, showing the effect of considerable transportation.

  

They are composed principally of quartz, Meta=andesite, granite,
quartz diorite, and diorite with pebbles of chalcedony, epidote,

gabbro and various fine grained metamorphic rocks. They overlie

  
 

 

29

the Superior in several places and as mentioned above, underlie
the Bear Creek Arkose. The formation is considered Tertiary
because of the rocks from which it has been derived, the occurrence
(which is typical of many parts of the Sierra) and relation to

the Arkose and Superior formation.

7. Bear Creek Arkose

 

The Bear Creek Arkose occurs in a belt south of Bear Creek
and west of the Bull of the Woods Extension claims. It consists
largely of a yellowish-white coarse grained sandstone made up
mainly of quartz and orthoclase loosely cemented with clay.

Under the microscope it is seen to be a medium grained
arkose consisting of seventy percent quartz, twenty percent
microperthite, five percent orthoclase, five percent microcline
and small amounts of apatite and zircon. The cementing material,
forming about thirty percent of the rock, is made up of a very
fine grained quartz mozaic with particles of feldspar, sericite
and iron oxide. The quartz greins are subangular and feldspars
little altered, showing that the formation was probably derived
from a granite mass not very far distant.

Along the West Branch and on the northern side of the
valley of the North Fork of the West Branch the rock has formed
prouinent outcrops, in some places nearly vertical cliffs thirty

or forty feet high. Along that valley the relation to the

 
 

30

gravels may be easily seen. The arkose is horizontally
bedded and lies conformably on fine to coarse red gravels,
Between the arkose and the gravels is a fine tuff colored a
deep red by iron oxides and about five to ten feet thick.
The tuff is well indurated and weathers in small flakes or
chips resembling the weathering of shale.
The arkose weathers in rounded forms and big masses of

it stand out over the underlying tuff and gravel which evident=
ly washes away faster. Masses of the arkose have broken off, fallen
down the steep slope and lie along the floor of the valley which is
four or five hundred feet wide.

The age of the Bear Creek Arkose is probably Tertiary in

view of its horizontal bedding and its relation to the gravels.

8. Coyote Peak Rhyolite and Andesite

The Coyote Peak Rhyolite lies in a belt on the Arrowhead
and Coyote claims about a half mile southeast of the Peak at an
elevation of approximately 6,500 feet. It consists essentially
of soft, loose, fine white and grey rhyolite tuff and ash with
a little agglomerate. It overlies the Superior granodiorite and
Meta-andesite and occurs at a higher elevation. It is at a
lower elevation than the Coyote Peak Andesite and apparently

underlies it.

 
 

31

The Coyote Peak Andesite is found in a broad area, in
the region of Coyote Peak, whose extent was not determined,
The formation was not traced or studied, except to determine its
relation to the rhyolite. The rock consists of fresh, unaltered
plagioclase in a fine grained to aphanitic dark grey and black
groundmasse. It occurs at a higher elevation than the rhyolite
tuff and apparently overlies it, making the andesite the younger.
The area over which it extends is practically barren of vegeta=
tion except for a little brush and a few small trees, The rock
has very little soil covering.

Because of their relation to each other and the granodiorite
and the fresh, unaltered appearance of the rocks the two formations

are here considered Tertiary.

IV.  Metalliferous Deposits and Prospects

 

le Gold Quartz Veins and Placers

 

Many years ago mining operations were carried on in this
pert of Plumas County, although only within the last twenty-five
or thirty years have prospectors located any but gold claims,
Placer mining operations have been carried on, ever since the
"discovery of gold in California, along many of the creeks and
gullies in both Recent and Tertiary gravels. At the present
time, none are being worked in the Lights Creek districts The

old Davis cabin, dating from about 1870, the Brickenal cabin and

 
 

 

others in the vicinity were built by prospectors, who in early

days panned the branches of Lights Creek and hydraulicked the

gravel banks in their search for gold.
The tunnel near the old Millsite on the West Branch just

south of Vendome #1 is located in a quartz vein as is Tunnel B

on Vendome #15, The arastra used in crushing their ore still

remains near the old Millsite. Further up the West Branch,from

the Bull of the Woods up, hydraulicking operations have been

carried on in the Auriferous Gravels exposed along the banks

of the streams The Sevenman Diggings in the gravels east of

Copper King #10 is also a site of early day placer mining.
At the present time none of the old placer locations

are sufficiently high grade or extensive enough to be of value

commercially.

2. Copper Prospects

(1) Copper King Claims

Occasional specks of chalcopyrite and bornite are seen
in the outcrops of the Meta-andesite north of Quigley Camp bub
the best showing in that formation is in the contact facies
at Quigley Camp. A tunnel has been put in for a few feet near
the contact, Malachite and ohrysocolla show in the outerop

in a smell percentage, while bornite and chalcopyrite were found

 
 

 

33

just under the surface in the tunnel. The bornite occurs in
small irregular veins in the rock with albite, quartz, orthoclase,
chlorite and epidote. Copper is only in a small percentage

but the prospect appears to be sufficiently good to warrant
further work.

Another occurrence on the Copper King claims also may be
worthy of developments On Copper King #9 a tunnel has been
started in the Engels diorite. The rock is pegmatitic, containe
ing black tourmaline and a little muscovite as well as quartz,
orthoclase, pyrite, chalcopyrite and bornite. The bornite and
chalcopyrite occur principally in small veins with the above
méntioned minerals, There is a good chance for further
mineralization near the contact. A tunnel or diamond drill
hole driven due west to the contact from a point lower down
near the creek would reveal any further copper mineralization,

The Copper King claims are accessible by a road which
branches off the Susanville road at the south end line of
Copper King #1 and runs to Quigley Camp.

(2) Vendome Claims

Prospect holes have been dug in several places on the
Vendons group but no signs of copper mineralization were found.
Occasional iron stains occur but no copper stains were associate

ed with them.

 
(3) Bull of the Woods Claims

 

No signs of copper mineralization were found in the
Engels diorite on the Bull of the Woods group and but a trace
in the Superior granodiorite.

On Bull of the Woods #1 just southeast of William's

cabin copper mineralization occurs which may prove to be of

commercial value. The Bull of the Woods quartz ledge about
twenty feet wide, strike N 30° E, stained with iron oxides,
malachite, and azurite may be traced for about two hundred feet
by the outcrops. A shaft sunk on the vein shows chalcopyrite,
bornite and some chalcocite and cuprite in leached and iron
stained quartz.

The Bull of the Woods claims are accessible by a steep,
narrow road branching off the Moonlight Valley road at the Ruffa
ditch and running north to Miriem fl.

(4) Miriam and Alma Claims

 

The Miriam and Alma group show no signs of copper mineral=
ization except on Miriam #1 and Alma jl. A vein a few feet
wide, the Rhinemiller Ledge, on Alma #1, can be followed for a
few hundred feet onto Miriam #1. The strike is approximately
N 45° B. A small amount of chalcopyrite and malachite shows
in the tunnel in the Meta-andesite but an inclined shaft on Miriam
#1 has the best showing. Theiron and malachite=stained quartz

vein, a few feet down, contains considerable chalcopyrite and

 
 

 

 

bornite. The Meta-andesite wall rock also shows some minerali-
zation. The showing in the Rhinemiller Ledge would justify
further development work.

(5) [Ironcap Claims

The Troncap group of claims showed very little copper
mineralization. Occasional traces of copper were found in the
Troncap formation but none in the Meta=-andesites or arkose.
A tunnel on Troncap #10 shows some pyrite with a trace of chalco=
pyrite. The hillside above the tunnel carried a good iron
gossan but very little copper stain, | On the contact on Troncap
#6 a slight malachite stain occurs.

(6) Uncle Sam Claims

 

Copper indications on the Uncle Sam group were poor, there
being only a few traces on Uncle Sam #3 near the Uncle Sem cabin.
At the southeast corner of Uncle Sam #3 a small percentage of
malachite and the sulfides occurred in the Meta-andesite, while
northwest of the cebin, malachite, chalcopyrite and bornite occas=
ionally were found in vesicles in the rock. The occurrence was
of interest geologically but of no importance commercially.

(7) Cuperite Claims

 

The only place on the Cuperite group which showed a trace
of copper was in the Superior formation north of the Thiem cabin
on Cuperite #11. Iron, manganese and slight malachite stains

with a trace of chalcopyrite are the only showing. The occurrence

 
 

 

 

is evidently of no commercial value.

(8) Menzanita, Arrowhead and Coyote Claims

The Manzanita, Arrowhead and Coyote groups of claims
showed no signs of copper whatever. Superior granodiorite
and Engels diorite as far as examined on the Contact group,

likewise showed no copper mineralization,

 
Tod

Looking north to
far d:

Coyote
oulpl

17
-.

stance).

by

he foreground 2 area of
dle distance. The ridge
marks the Plumas Coe -

neon MN
A556 U0

in

 
Plate I.

Looking north to Coyote Peak (the
the far distance). Sulphide claims
foreground. The
le distances The ridge in
the Plumas Cos - Lassen Coe boundary

 
.

a)

Cabin

urnt

" - 4.1 " ™
near wile op

reex

Q

0
>

}
"3

Ligh

Wa
3

 
 

~ Fig. 1
Outerop of Superior
granodiorite along Bear
Creek on Bull of the Woods
Extension #1.

 

Fig. 3

Sandstone bluffs on
Troncap #6 as seen across
Bear Creek Valley.

 

Plate

 

 

 

Fig. 2

Sandstone bluffs
on Troncap #6.

 

 

Fig. 4

Bear Creek Arkose over=-
lying tuff and fine gravels,
south of Troncap #15. Tuff
and gravel in the foreground.

III
 

- Figs 1
Prominent outerops of
horizontally bedded arkose,
south of Troncap #15.

He. 3
Red gravels underlying
the tuff and arkose shown
in Figure 2 above.

 

 

Plate IV

 

Fige 2
Arkose overlying
red tuff and gravels,
south of Tronocap #15.

 

Fige 4

Gravels which have
been hydraulicked, near
the West Branch on Bull
of the Woods Extension

#24

 
usA

fi sepa Ve)

2

. | - 8 l 9 a b g 2 JuLIN
i bio gt git tt OL 164 18) ll Sil & 2 nm

U.S.GEOLOGICAL SURVEY RECONNAISSANCE MAP
GEORGE OTIS SMITH, DIRECTOR.

4 (Alturas)
, 121 30

CALIFORNIA. &
HONEY LAKE SHEET 45

144

 

ADELINE PLAINS

 

 

 

 

 

 

 

 

sy)

 

@®
2
8
:
~

 

 

 

 

 

 

 

 

 

 

 

0
F rs Gannett.Chief Geographer.
oY Gilbert Thompson, Geographer in charge,
FH Triangulation by the Wheeler Survey. ‘
& Topography by J.D.Hoffman and AF. Dunnington.
and the Wheeler Survey.

Surveved in 1882

7

NOEL OY
45{ Downie

 

 

 

Edition of July 1893, reprinted June 1913.

 

| ek pg Contour Interval 200 feet
AED] Survey]

3) foe THE A. LIETZ C0,
ANN eelegt 61 POST SFREET
SAN FRANCISCO, CALIF,

 

HONEY LAKE

 

 

 

 

 
THE TOPOGRAPHIC MAPS OF THE UNITED STATES

The United States Geological Survey is making a topographic
atlas of the United States. This work has been in progress
since 1882, and more than 38 per cent of the area of the
country, excluding outlying possessions, has now been mapped.
The areas mapped are widely distributed, every State being
represented, as shown on the progress maps acompanying each
annual report of the Director.

This atlas is being published in sheets of convenient size,
about 16% by 20 inches. * The four-sided area of land repre-
sented on an atlas sheet is bounded by parallels and meridians
and is called a quadrangle. The quadrangles mapped cover
1° of latitude by of longitude, 30° of heise by 30 of
longitude, 15’ of latitude by 15’ of longitude, or smaller areas
the size of the area mapped depending on the scale used.
Several scales that used
1:250,000, or very nearly 4
4 linear miles on the ground is
represented by 1 linear inch on the map. This scale is used
for maps of the desert regions and some other parts of the far
West. For the greater part of the country, which is mapped
by quadrangles covering 30, a larger scale, 1:125,000, or
about 2 miles to an inch, is employed. A still larger scale,
1:62,500, or about a mile to an inch, is used for quadrangles
covering 15, the unit selected for mapping thickly settled or
industrially important areas, A fourth seale, 1:31,680, or one-
half mile to an inch, is employed for maps that are to be used
in connection with irrigation or drainage, and a few maps of
mining districts are published on still larger scales.

A topographic survey of Alusku has been in progress since
1898 and nearly 30 per cent of iis éntire area has now been
mapped. One-third of the area mapped, or 10 per cent of the
Territory, hag been covered ouly by reconnaissance work, the
results of which have been tapped on a scale of about 10 miles
to an inch. The maps of nearly all the remaining two-thirds
of the surveyed area have been published on a scale of
1:250,000, or about 4 miles to an inch. These maps are lirge,
each representing 2° of latitude by 4° of longitude. A few
arens that are of economic importance, aggregating about
3,000 square miles, have been surveyed in greater detail and
“mappedon a Seale of 1762;500, or about a mile fo an inch.

A survey of the Hawaiian Islands was begun in 1910 and
the resulting maps are being published on a scale of 1:62,500.

The features shown on these atlas sheets or maps may be
leassed in three groups—(1) water, including seas, lakes, rivers,
canals, swamps, and other bodies of water; (2) relief, includ-
ing mountains, hills, valleys, and other elevations and depres-
sions; (3) culture (works of man), such as towns, cities, roads,
railroads, and boundaries. The conventional signs used for
these features are shown below, with explanations. Variations
appear on some earlier maps.

are emploved. The smallest scale,
for quadrangles covering 1°, is

miles to an Inch—that is,

All water features are printed in blue, the smaller Streams
and canals in full blue lines and the larger streams, lakes,
and the sea in blue water-lining. Intermittent streams—those
whose beds are dry at least three months in the year—are
shown by lines of dots and dashes.

Relief is shown by contour lines in brown. A contour on
the-ground passes through points that have the same altitude.
One who follows a contour avill go neither uphill nor downhill
but on a level. The contour lines on the map show not only
the shapes of the hills, mountains; and valleys but also their
elevations. The line of the sea const itself is a contour line,
the datum or zero of elevation being mean wea level. The
contour at, say, 20 feet above sea level would be the shore line
if the sea were to rise or the land to sink 20 feet. On a gentle
slope this contour is far from the present coast; on a steep
slope it is near the coust. Where successive contour lines
are far apart on the map they indicate a gentle slope;
they are close together they indicate a steep slope;
they run together in one line they indicate a cliff.

The manner in which coutour lines express altitude, fori,
and grade is shown in the figure below.

where
and where

 

 

 

 

 

 

 

 

The sketch represents a river valley between two hills, In
the foreground is the sea, with a bay that is partly inclosed
by a hooked sand bar. On-each side of the valley is a terrace
into which small streams have eut narrow gullies. The hill on
the right has a rounded summit and gently sloping spurs sepa-
rated by ravines. The spurs are truncated atstheir lower ends

CONVENTIONAL SIGNS

CULTURE
(printed in black)

by a sea cliff. The hill on the left terminates abruptly at the
pti]
slope 8 from

valley in a steep scarp. It §
the scarp and forms an inclined table
by a few shallow gullies.
1s indicated, directly beneath
contour lines.

The contour interval, or the vertical distance in feet betw
one contour and the next, is stated at
This interval differs
mapped; in a flat country it may be as small as 5 feet;
mountainous region it may be 250 feet. Certain contour Ii
every fourth or fifth one, are made heavier than the
and are accompanied by figures
level. The heights of many points, such as road corners, sum-
mits, surfaces of lake
map in figures, v
foot only. More
geodetic coordinates of triancu
bulletins issued by
taining to

rradually
land,

ie map each of these features

back away
which is traversed
On tl
in the ske

its po )S1 tion

the bottom of eacl

:
according to the character of

stating elevation al

ove sea

es, and bench marks, are also given on the

whi ¢h e Rpress | he ele vations to the nearest

+ 2 - Fahioh 3 5 welling
elevations Of Dencn Marks, as weil as

exact
lation stations, are published in

3 1 : ‘ A fo el
the Geological Survey. A bulletin per-

1 on applic

The works of man are shown in black, in which color all
lettering also is printed. Boundaries, such as those of a State,
county, city, land grant , township, or reservation, are shown
by continuous or broken tines of different kinds and weights
Public and through roads are shown by fine double Foes:
private and poor Tous by dashed double lines; trails by dashed
single lines. L

Each quadrangle mapped for the topographic atlas is desig-
nated by the name of a principal town or of some prominent
natural feature within the quadrdngle, and on the margins of
the maps are printed the names of adjoining quadrangles for
which atlas sheets have been published or are in preparation.
The sheets are sold at 10 cents each in lots of less than 50
copies or at 6 cents each in lots of 50 or more copies, whether
of the same or of different sheets.

The topographic map is the

my State may be h: ition.

base on which the geology and

8

the mineral resources of a quadrangle are represented, the maj
showing these features being bound together, with a description
of the quadrangle, to form a folio of the Geologic Atlas of the
“United” States, Circulars showing by index maps the piib-
lished topographic atlas sheets and geologic folios covering
any State or region will be sent free on application.

Applications for maps or folios should be accompanied by
cash—the exact amount—or by post-office money order and
should be addressed to—

THE DIRECTOR,
United States Geological Survey,
Washington, D. C.
January, 1913.

 

 

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Roads and Meraled road Privade ox
buildings {distinguished on SOCOT
maps andy} road
po 3

Trail or

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Railroads Electric

path railroad

ete Bridges
and i jetties

Drawimidges Ferry

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—— a

‘anal lock TUS.township and State me
a 1p strewn) section nes

and loc: ated comers
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Chur Tr School € Coke ¢ ovens

{ istingndshed orn
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RELIEF

(printed in brown)

 

 

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—
Civil Towns ship

or district line Ine rough line

City village or Small park or Triangulation
cemeteryline or primary

 

5 Soden al
monmment
averse monnmment

De
Boundary
monument

 

|

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fea retinal nants in
Oil wells Mine ar Shaft Mine tunnel

Mine tunel
(showing direction ){ direction unknown

{
imei nb
=

Life -saving

station

Lighthouse :

ar beacon

Light- ship

WATER
(printed in blue)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1 Jopression
cont ora Ss

 

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Wash Mine dumps

Send and
sand dunes

 

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Sa TW
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“Fal s Fy
rapids

Tatermittent
streams and
ditches

Canals or
ditches

 

Aqueducts or

 

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Intermittent Spring
lake {Or shown toy Rpts Pring

WOODS
(shen shown, printed Wa gveon)

Salt ry _t

 

 

 

 

 

marsh Grassy pond

 
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LEGEND

Jed imen tary
Roc Ks BCA

Bear Creek
Arkose

7e rliary

grv

Auriferous

201 21 Lgneous
| Roc HAs

7 ertiary(?)

rhyolite tuff
: and agglomerate.

J z Sgdr
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Superior
Granodiorite.

Egdi

Engels :
grorodiori fe
and dierite.

 

Ap

MIA
Meta-andesite.

——
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——-——

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Surface
Copper Showings

Discovery fole

 

 

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Prospect
furnrmel

Il
Prospects

cut

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Contac?
me tarnorphosed
ardesire.

Surface
Copper showings

i Varrs
RICEM|E R./0E.

Discovery l1ole

 

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—————
PI ————————
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GEOLOGIC MAP

OF THE

COYOTE PEAK

DISTRICT Seeing fr 0 § | Sg

yn it ©3.6.
PLUMAS CO. oo le

 

RANGER STATION)
Scale 1"=600'

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Base Map -H.0.Thiem. Geology -G.B.0aKeshott. he

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END OF TITLE