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Ickes, E. L.

Geology of eastern Oregon

 
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University of California at Berkeley Library

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GLADIS NUMBER: 18478725230 : BK AD:991009/FZB
LEVEL:b BLT:am DCF:a CSC:d : EL: 7 UD:030604 /MAP
CP: cau L:eng INT: GPC: : FIC: CON: ARCV:
PC:S PD:1909/ REP: : FSI: ILC: ITI:0

CUScCU
SbDISS.ICKES.GEOL 1909
Ickes, E. L.
Geology of eastern Oregon.
Scl909.
38 p. :Sbcol. maps ;Sc29 cm.

20 University of California, Berkeley.SbDept. of Geology and
GeophysicsSxDissertations.

0 Dissertations, AcademicS$xUCBSxGeologySy1901-1910.

Microfilmed by University of California Library Photographic Service,
Berkeley, CA

 
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Theses, LL, Ickes , 1909, TCKes

GEOLOGY OF EASTERN OREGON. jag
: 1q0
LOCATION. GRIC
The aree covered by the writer in the summer of 1908 and embodied

in this paper is & strip of territory, from six to twenty miles in

width, extending in a west of north direction across the quadrangle

bounded by latitudes 43° 40' N, and 44° 20' N., and longitudew 117°
and 117° 50' W. of Sreenwioh. The southern portion of this strip is
included in the northern helf of the of the Mitchell Butte topographic
sheet issued by the government; the northern portion has been survey-
ed by the government but no map has been published as yet.

Within this area all the formations reported in Eastern Oregon,
except the Archaean, are to be found, and the section is believed to
be feirly typical of the geology of this part of the state.

CLIMATE, TOPOGRAPHY, AND DRAINAGE.
Eastern Cregon and western Idaho have a semi-erid climate; a dry

werm climate prevails with but little rain or snow. The climate of the
Blue Mountains immediately to the north is a variable one, owing to
the great diversity in elevation and situation.

The vegetationof the uncultivated portion of the region consists
of greasewood, sage and wild grass. The only timber is found along the
streams and is .m&de up of willow, cottonwood, and allied forms.

The extreme northern portion of the strip is known as the foot-
hill belt. Wide, monotonous tablelands of basalt preveil, with low
hills ani ridges made up of both Tertiary and Pre~Tertiary rocks.
Canyons and gulches are not of general occurrence, and when found
expose steep sides and narrow widths. The average elevation of these
lava covered table lands is something over 3200 feet, and to the north
the country rises gradually in elevation to about 5000 feet. Along the
western side of Willow Creek valley is a high range of lava capped
mountains, known as the Juniper Range, extending southward from the

foot-hills in the neighborhood of Cow Valley & dozen or so miles, Por-

tions of tMis range reach an elevation of 6000 feet.

f }

#2
With the exception of the Juniper Range and their extension, the

Bouble Mountains, fifteen miles south, the rest of the country is made
up of low hills and ridges separated by wide valleys. At Kern Basin
in the extreme southern part of the strip, & topography is found sim-
ilar to the so-called Bad Lands topography, but elsewhere steep and
precipitous cliffs are not common.

The Snake River is the drainage outlet of the entire region; with
in the quadrangle itself are two drainage systems, one controlled by
the Owyhee River, the other bg the Malheur River. Both of these streams
are of considerable size, especially in the winter months. The Owyhee
drains the most southerly portion, the Malheur the central and northern.
part.

The lower eight miles of the Owyhee River passes through a broad
rolling valley worn from the Tertiary sediments; but 2 few miles south
of Mitchell Butte the river enters a steep and narrow canyon cut in
a series of basic lava flows, and continues in this gorge as far as
it was followed, a dozen miles south.

Between the Owyhee and Malheur is a broad highland about fifteen
miles in width, with an average elevation of 500 feet above the two
rivers which are at practically at the same altitude of 2200 to 2300
feet.

The Malheur Valley, extends in an east to west direction across
the Quadrangle. It is wide and flat and on the north and south is
bounded by low hills and ridges made up of the Tertiary sediments.

Extending northwesterly from Vale and through the foot-hills is
Willow Creek Valley. Willow Creek itself is almost dry in summer and
of unimportant size in winter. The valley is several miles in width,
rising graduldlly from an elevation of 2270 feet at Vale to 2900 in
the canyon several miles within the foot-hills. The hills on the east

side of the valley reach an elevation of 3500 feet, and on the western

3500 feet to 6000 feet in the Juniper Range

 
#3

The chief landmarks south of the foot-hills are prominent buttes

rising from 500 feet to 1200 feet above the surrounding country. The

most conspicuous of these are Vale, Chalk, Mitchell end Deer Buttes.

LITERATURE.
Various geologists have visited this part of Oregon and Idaho,

among them being Cope, King, Eldridge and Lindgren. Until the results
of Mr. Lindgren's work were published, the geology was in a very un-
setisfactory state of affairs. The work of King and Cope was local,
applying only to limited portions of the territory. Eldridge made a
reconnaissance through Idaho and his observations are published in the
16th Annual Report, U.S.Geological Survey, part 2. pps. 2B7-276.

King ( U.S.Geological Exploration of the 40th Parallel, Vol.l,
1878,pp. 418, 440 ) visited the country between Castle and Sucker Creeks
and noted " large accumulations of basaltic flows" intercalated in the
Pliocene beds,

Cope ( Proc. Phila. Acad. Sci. 1883, pps. 1563-166) studied the
fresh water fishes collected by King and Vortmen, and geve the name
Idaho t© the formetion from whieh they were obtained. Crawfish and
mammilian remains were also collected from the Idaho beds, Cope placed
the Ideho Formation in the Pliocene.

Lindgren has made the most valuable contributions to the literature
on the region. He differentiated a formation earlier than the Idaho
in the Tertiary series, and gave it the name Payette. Study of the flores
collected in this formetion led Dr. Knowlton to assign an upper Iiiocene
age to the rayette,(see 18th Annuel Rep't. U.S.Geol. Survey, Part 3,
pps. 727-744), but later he placed it in the Eocene,(see Bull. 204,
U.S.Geol. Survey, pps. 110-111). kr. Lindgren's reports are to be found

in the following publications of the Geological Survey:

#4
"The Mining Districts of the Idaho Basin and the Boise Ridge, Idaho"

18th Annuel Report, Fart 3, pps. 625-719.
"The Gold and Silver Veins of Silver City, DelLamar, and other lining
Districts of Idaho", 20th. Annual Rep't. Part 3, prs.75~-25b6.
"The Gold Belt of the Blue Mountains, Oregon”, 22d Annual Report, Part
2, pps. 561-776,
Boise Folio, No.45; 1897. Nampa Folio No. 103,1902, Silver City Folio
No. lo4, 1902.

Also, in Science, new series, Vol. 13, pps. 270-271, he gives a

short account of the distribution of the Trias in northeastern Oregon.

I.C.Russell has also made explorations, more of 5 prelininary
neture, into this territory, and his works are to be found in the U.S.
Geological publications as follows:

"Geology and Water Resources of the Snake River Plains of Idsho"
Bull. No0.199, 192pps.

"Notes on the Geology of Southwestern Idaho and Southeastern Oregon"
Bull. No. 217, 83 pps.

"Preliminary Report on the Artesian Basins in Southwestern Idaho and
Southeastern Oregon", U,S.Geol., Surv. Water Supply and Irrigation
Peper lio. 78, bl pps.

"Preliminary Report on the Geology and Water Resources of Central Ore-

gon", Bull.No.252, 138 pps.

And, in addition, an abstract in Science, new series, Vol.1l5, pps.85-86

on the "Geology of the Snake River Plains of Idaho".

C.Weshburne collected fossils in eastern Oregon, and gives some

notes on his observations in Jour. Geol. Vol.ll, pps. 224-229, 1903.

 
#5

GENERAL GEOLOGICAL FEATURES
The Blue Mountains are made up largely of Pre-Tertiary rocks,

intruded with gresnite, serpentine and the like. Tertiary lava flows
covering the surface in the mountains are of wide occurrence, and
detached areas of Tertiary sediments are found in the older valleys.
The territory cevered by this paper does not extend into the Blue
Mountains proper, the most northerly pottion being the southern foot
nills, and the geological features outlined are from Linggren.

About 26 miles north of west of Baker City is a small area of
coerse grained biotdte gneiss, showing pronounced schistoeity. Mr.
Lindgren believes it to be of Archaean sge and of sedimentary origin.

A considerable proportion of the Pre-Tertiary recks exposed in the

Blue Mountains are of Paleozoic age, end consist of clay slate, cherts,

silicious argillites, with a little limestone and eruptive rocks. The
series bs sharply folded and compressed, but rarely schistose. The
few fossils so far found point to a Carboniferous age for most of the
Paleozoic rocks.

Northeast of Baker City on Eegle Oreek, 30 miles in an air line,

fossils have been found in a thick series of calcareous
and limestone, associated with lave flows and tuffs.
A similiar series is td be found near Huntington, in the south-

eastern portion of the Blue Mounteins. Immediately north of this town

is an area by 35 miles in extent and & northeast to southwest trend,

consisting of limestone, calcareous shale, clay slate and volcanic ash
resting © a series of older leva ws an ffs now altered to
greenstones., A few roun& crinoid stems were found in this section, end
Lindgren inclines to the view that these rocks are of Triassic age,
giving to7$em the name H@ntington Series.

If the Huntington series is of the same age as the Triassic of
Baple Breek , it suggests that the Blue liountains are in the nature of

a)

a broad anticline uplifted in Post- Triassic times» Put the details

#6

of mapping are not sufficient at present to warrant such a supposition.
The distribution of the Triassic sea in the west, according to

J.P.Smith ("Comparative Stratigraphy of the Marine Trias of Western
America ", Proc, Calif. Aced. Sci, 3d Series, Geology, Vol.l, FNo.1lO0,
1904)is only dmperfectly known, but the eastern shore line seems to
have ran up through eastern California, Utah and western Wyoming inte
Ideho and Montana in lower Trias, retreating westward until in the upper
Trias it appears to have been a gulf in Northern Californie and central

Nevada. Assuming such a distribution of the sea as true, the Triassic

of the Blue llountains can be placed well down in the Triassic, and maybe

of the same age or a little younger than the lower Triassic reported in
te Aspen Mounteins in southeastern Idaho.

Following the Trias the region was intruded with lerge amounts of
granitoid rocks as batholithic masses,

No Jurassic or Cretaceous have been recognized within the Blue lits.
themselved, but rocks of these ages are to be found in the John Dey
region to the west.

On travelling southward from the foothills, the last exposures of
the Pre- Tertiary rocks are to be seen about 6 miles north of Dell P.O.
All the country to the south of this is made up of the Tertiary sediment:

and lava flows, the former predominating. The sediments are largely

soft sand and shale, with minor amounts of volceandc ash.

The Tertiary deposits have been divided into two formations: the
oldest described by Lindgren as the rayette; the youngest named the
Idsho by Cope, who applied the name to the formation from which the
verterbrate remains were collected by King and Wortman.

According to Lindgren the Snake River was developed in early Ter-
tiery times, and the Payette formation was deposited in a lake formed
by a damming of the Snake near Huntington by thick lava flows, called
by him the Columbia lava. After reaching an elevation of whatis now

about 4200 feet the lake began to drsip

 
 

#7

and when the shore line had sunk to what is now 2800-3000 feet a halt
occurred in the subsidence. At this stage of the lake the sediments of
the Idaho formation were deposited, accompanied by some folding in the
Payette beds and their erosion into the Idaho lake along the borders.
After the deposition of the Idaho beds the lake was drained and the
present Snake River established, in practically the same channel as the
older stream.

The above sequence of events as outlined above and given in Mr,
Lindgren's early reports was perfectly compatible with the falaeontol-
ogical determinations on the age of the Payette and the Columbia lava.
In all of his reports lindgren assigns the Fayette to the Upper Miocene,
as determined from flora collected in the Payette and worked up by Dr.
Knowlton. But subsequent work on some of the flora of the Tertiary beds
of the John Day Basin led Dr. Xnowlton to place the Payette in the Eec-
ene, In this connection he says("Fossil Flore of the John Day Basin"
Beil. 204, U.8.5.8.,00.110);

"In 1898 I published a report on the Fossil Plants of the Payette
Formaetion( 18th An. Rep't, Pt.3,pps. 727-744).... In this report the
Fayette was referred to the Upper Miocene, but I was misled by the
knowledge then current regarding the age of the Bridge Creek beds and
it is now necessary to change thatreference. The flora of the Payette
formation :ndoubtably finds its greatest affinity with that at
Bridge Creek, a fact recognized all along, and, like it, is now referred
to the Upper Eocene.” In folios Nos. 103 a nd 104 Lindgren mentions
this reference, but offers no suggestion as to the relation of the
Feyette and Idaho other than they were probably not deposited from the
same body of water.

The reference of the Payette formetion to the LKocene complicates
the use of the term Columbia lava. In the John Day Basin the thick
lave flows referred to the Columbia lava by Prof, Merriam( Bull.

Dep't. Geol, Univ. of Calif. Vol.2, No.9, pps.269-314) are of un=

2S cot ionatay Miocene age, whereas Lindgren's observations would place
it in the Eocene. Mr. Lindgren regards the heavy lavas below Huntington
as Pre-Payette, for he states that the Payette lake was due to a damming
of the Snake River by the lava floods; also in Folie Ne. 103 he says:
"These basalts are usually referred to as the Columbia Kiver lave, and
the bulk of them has been considered as of Miocene age. As most of the
Older basalts in this region antedate the lake beds, and as the older
beds have recently been determined as Eocene, it would follow that a
large part of the Columbia River lava in this portion of Idahe is of
early Eocene age", Also in a letter to the writer he said:" The prin-
cipal differrence between the Payette and Idaho as 1 saw it wae that
ke former followed the extensive eruptions of rhyolite and Columbia
basalt, while the Idaho formetion, separated from the former by a long
period of erosion, was contemporaneous withthe ruption of thin basalt
flows characteristic of the Snake River Basin." It is pretty evident
from the above that Iir, Lindgren regards the heavy flows he assigns to
the Columbia River lavas as Pre-Peyette., Taken in connection with the
Miocene age of the thick flows further west, such 2 broad &pplication
of the term does not seem justifiable, but Mr. Lindgren probably uses
it in the sense first proposed by I.C.Russell(Bull.l08,pp20) whe applies.
it te all Tertiary lavas along the Celumbia Drainage.

Prof. Merriam suggests(lec. cit. pp.303) that the term Columbia
lava be restricted to the heavy Miecene lavas, and the suggestion seems

to be a very reasonable one,

 
ko

THE PRE-TERTIARY SERIES.
These rocks are first exposed in the foothill belt in the nerthern

pert ef the region covered. On account of lack ef time and the press-
ing need of other work at hand, ne attempt wes made to differentiate
the Paleczeoic and the lieseozoic ot the map, and no extended search was
mede for fossils. In this area it is possible to distinguish two
series older than the Tertiary, end these, &s will be shown later, are
referred to the Huntington and Faleozoic series of Lindgren.

In the foothills it is possible to recognize a series of shales,
argillites, tuff and lava flows, with the bedding inclined only a few
degrees; these rocks are underlain by limited exposures of black
silicious slates and fissle shales which showed no evidence of bedding.

The upper formation is tentatively correlated with Lindgren's Hunting-

ton Series, because it is situated on the strike of the beds mapped

by him around Huntington, and also agrees withh81at dip of the series

about that town. The underlying slates and shales are assigned to the
Paleozoic.

About 6 miles mor th of Dell F.0. & series of beds made up
of limestone, shale, and what is probably tuff and altered laves, ere
exposed at an elevation of 2900 feet as determined by an aneroié bar-
ometer. The bedding has a general dip of 30° to the northwest. The
section crossed perpindicular to the strike wes about a mile, and in
this the rocks were all of this series. The beds are much indurated
and in places show considerable evidence of compression. This series
appears to be overlain by thin bedded basaltic tuffs with an intercal-
eted basalt flow, which occur in a .small area to the south. Over the
basalt is a thick bed of an acid tuff, These last mentioned rocks do

show the induration and compression observed in the underlying
which are referred to the Huntington Series, and as they dip
8.20°W. undef flat lying beds of the Idaho formation,

they are here correlated with the Payette formation,

£10

The next exposure of the older rocké encountered is 6 miles to the
west, extending from the vicinity of Emery Cole's ranch westerly thro-
ugh Road Canyon and Cow Valley Butte. Owing to the thin covering of
thin £1. 0 Ww s of Tertiery basalt which form: wide teblelands in the
region, and with the lake beds covers the underlying formations, ex-
posures of the older rocks are not nugerous. In the vicinity of Road
Canyon the following section can be made out:
1. Near the road are exposed at least 300 feet of 0ld lavas and tuffs;
in places thin beds of black shale occur between the flows. Dip 18° to
30°N.¥.
2. Over No.l are several hundred feet of black shales, apparently inter-
bedded with minor amounts of tuff and lavas, but the exposures are poor,
North of the canyon, the tops of several granitic intrusions are to be
found. These project through the Huntington Beries,

These rocks have developed in them a secondary cleavage, dipping
generally to the northwest and west at high angles across the flatter
bedding planes. Similiar compression planes were not noted in the in-
trusives, suggesting that the cleavage was developed prior to or during
the formation of the batholiths.

Cow Valley Butte, five or six miles west of Koad Canyon,affords the
next exposures of the older rocks. This butte is a huge mass about 8
miles in circumference, rising 1500 feet above the lave covered floor
of the valley. elevation on the butte, as determined by en
aneroid, is 5300 feet.

On the western side of Cow Valley Butte the first evidence of the
Paleozoic is encountered. This series is represented by 500 feet of black
silicious slates standing about vertical end showing no evidence of bed-
Qing. Over this is about 1000 feet of black shale, tuffs and thin lavs
flows, referred to the Huntington Series, as they lie about flat and
resemble the Huntingtdn beds of Road Canyon. An almost vertical cleav-

age has been developed in these rocks, also.

 
11
The most interesting feature of Cow Valley Butte is the occurrence

of a large intrusion of Granitic rock, which forms the core of the butte,

 

the Pre-Tertiary series being exposed on the east and west flanks, while
on the north and south sides are Tertiary basalts forming the level of
the valley, their present position being due to faulting.

The granite is the gray colored biotite type found throughout eas
Oregon and Idsho. The distance between the east and west walls is about
eg mile, Near the periphery of the mass numerous dykes of lemprophyre
cut the granite, but do not extend for any distance into the granite
itself. any small aplite dykes and quartz stringers are also found
cutting the granite, and with the lamprophyre dykes appear to bear a
pretty constant relation to each other. Generally the quartz stringers

are cut by aplite, but some instances were noted where the two seemed

 

to grede into each other; the contact with the granite is well defined
as & rule. The lamprophyre appears to have been the latest intrusion,
( as it cuts the granite, aplite and quartz.
There ig little doubt as to the intrusive nature of the granite.
Irregular masses of the wall rock sre to be found in it, and small dykes
and apophyses were noted extending into the Huntington Series.The walls

-

especially where composed of shale or slate -are often almost entirely

replaced by silic hrough considerable distances from the contact
with the granite. The following section in an east to west line may

serve to show the reletions more clearly:

Elev. Too Lf
em
Fer

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ern gton ey ay
Vv
PAC yaa JY Vv v vv Vv vv Vv vy /
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A dyke of basalt was also noted in the ersnite. It

in ite

Section Through Cow Valley Butte.

  

    

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£12

and traceable in an east to west direction for a quarter of a mile. It
is apparently the source of some of the Tertiary lave flows in the vie-
inity.

The only serpentine noted in this portion of the Blue Mountains
occurs as a dyke several hundred feet in width, cutting the Pre-Tertiary
rocks in a northwest to southwest direction where Mormon Besin Creek
empties into Willow Creek.

AGE OF THE GRANITIC ROCKS.
In the area covered by this paper no evidence wes found whereby the

dete of the granitic intrusions could be determined in any more than

& general wey. They evidently sre intrusive into the Triassic, and
granitic pebbles are foung in the Pliocene sediments which also rest

in an unaltered condition on the Pre-Tertiary rocks near the intrusions.

This places the intrusions between the Triassic snd the Fliocene,

Some light is thrown on the question by the secondary cleavage
occuring in the Huntington Series. Yo attempt was made to work out the
relation between the cleavage and the grenite, other than it was not
noted in the intrusive rock itself. On Cow Valley Butte the writer
gained the impression that the cleavage was lergely parallel to the
gtenite contact. The cleavage, then, does not appear to be younger than
the granite.

The combination of secondary cleavage in rocks associated with ex-
posures at the surface of igneous masses supposed to be of deep seated
origin, suggests thet the Huntington Series, which has but & small in-

-
i

clination of bedding, was at the time of the developement of tlie cleav-

ry

ages covered by a superimcugbent mass of such thickness that the pres-

sure developed cleavage and not folding in the beds. The absence of

similiar cleavage in the Idaho deposits and the older tuffs beneath
the Pliocene, which the writer correlated with the Payette, as well as

the manner in which these Tertiery deposits overly the older rocks

along the flanks o a f 'i points t ]
long ks of the foothills Points to the fact that the

 
    

  
fiz

the superimposed mass was removed before the Tertiary and after the
developement of the cleavages. The granite appears to be either cont-
emporeneous with or later than the cleavage, and the occurrence of

the eroded surface of the granite at about the same elevation as the
Pertiary deposits suggests that considereble erosion took place before
the Tertiary. Such & hypothesis would plece the granite as Fost-Triassic
end Pre-~Tertiary.

On the South Fork of the John Day River, south of Dayville a few
miles, in a region which may be included in the foothill belt of the
Blue Mountains, the writer found Upper Cretaceous(Chico) sandstone on
one flan¥ of & huge grenitic mass. The sandstone was only moderately
indurated, and the granite had undoubtaebly been formed and exposed by
erosion prior to the Upper Cretaceous deposition. If the granites of
the region are of the seme esge, this fact places their formation as
Post-Triassic end Pre-Chico.

The huge batholiths of California are placed in the early Cretaceous

and from the information at hand it seems probable that these of Oregon

and Idaho may be of the same age. The whole territory west of the

Wasatch Mountains, and extending from lexico to Alaska, shows evidence

of vest granitoid intrusions in Mesozoic timed, and from the enormous
size and extent of these batholiths, it is ressonable to suppose that

they are closely connected in age.

f14
TERTIARY FORMATIQNS.
The differentiation of the Tertiary formations in the Snake River

Basin is difficult, and heretofore no attempt has been made to sep~-
erate the Eocene from the Pliocene in meppimg. In Folios Nos. 103 and
104 the Payette and Idaho formations have been mapped as one, owing
to the difficulty in distinguishing between them.

In the area covered by this paper, it is possible to separate two
formations in the so-called lake veda. The lower of these was called
the Payette, the upper one the Idaho, A description of them was sent
to Mr. Lingdren, of the U.S. Geological Survey, who wrote in reply
that they agreed with the Payette and Idsho as recognized by him as
far as he could judge from the notes sent.

PAYETTE FORMATION.

As will be remembered, the latest work on the Payette flora by
Dr. Knowlton has led him to assign an Upper Eocene age to this form-
ation, instead of an Upper liocene as given in most of Lindgren's
reports, based on earlier determinations of the floras by Knowlton.

In this area, most of the Tertiary beds exposed are referred to the
Pliocene; in comparison to which the extent of the Fayette exposures is
small, and occupy relatively minor areas.

The Owyhee River Canyon, south of Mitchell Butte a few miles, is
made up of numerous sheets of basic lavas, with some of a more acid
nature, piled one upon another through a height of 800 feet at least.
The bottom of the series is not exposed, and the upper portion, as
viewed from a distance, is intercalated with the Tertiary sediments
presumably Payette.

In Kern Besin, 4 mbles west of the canyon, a series of sands, shale
tuff, and lava flows are exposed, aggregating 800 feet at least. The
beds all pitch westerly, and only remnants of the Idaho formation cap
the highest hills about the basin. The Kern Basin beds are referred to

the Payette, and are apparently divisible into two parts, separated

 
 

 

  

 
  

#15
by an irregular contact. The time spent in this neighborhood was limited
but the following section was made out:

Along the eastern side of the basin is exposed & stratum about 100
feet thick of coarse, massive, buff sandstone, often crossbedded, and
considerably indurated and hardened. This is overlain by 60 feet of
acid tuff-"chalk rock" - with anguler rhyolitic fragments, and this in
turm in the central part of the basin, by & considerable thickness of
grey shale, which weathers into huge bullet sheped forms. These sheles
ere probably unconformable with the overlying beds as an irregular con-
tact was obeerved between them an#h the shalgés appear to have a greater
piteh to the north than the beds above. The upper formation ¢s mede up
of light colored sands and shale, about 700 feet in thickness, in which
is imbedded a 60 foot layer of rhyolite breccia and ash, and intruded
by an irregular basalt sill. The upper portion also contains three
seams of highly carbonaceous clay, in which leaves snd grasses can be
recognized. Looking from the western side of the basin toward the
Owyhee River, it can be seen that the lava flows forming the walls of
the canyon have the appearrance of dipping under the Kern Rasin format-
ions. If this is so, and other evidence points to the fact, these lavas
may correspond to the thick flows reported by Lindgren as occuring be-
neath the Fayette and called by him the Columbia River lavas.

On the southeast side of llitchell Butte is exposed a coarse,hsrd,
buff sandstone, sometimes crossbedded and resembling lithologically
the sandstone along the eastern edge of Kern Basin. The following fossils
were here collected: one resembling & Carnifex, another a small Sphae-
rium, and the cest of a gasteropod probably & Fluminucola.They were
&ll poorely preserved. Over this sandstone is about 100 feet of fine
white sandstone, which on weathering shows fine bedding. The bedding
observed in the coarse buff sandstone is at a variance with that of the
fine sandstone above it, but whether this wes due to current action

or to an unconformity was not clear.

 
 

 
  

  

#16

The upper fine sandstone is overlain unconformably by the Idaho

formation, which forms most of the butte.

If the coerse sendstone at the base of Mitchell Futte corresponds
to that on the east side of Xern Basin, and there is n o evidence of
this other than in thetr similiar lithological sppearrance, an inter-
esting deduction can be drawn regsrding f¢ Payette deformstion. In
Kern Besin at least 800 feet of sand and shale separste the sandstone
from the Idaho beds, while on litchell Butte the thickness between them
is only 100 feet msde up of sandstone.Such a correlation suggests thst
the Payette was folded and eroded before the Idaho deposition. Also
the indications of an unconformipy in the Payette itself in both Kern
Basin and on liitchell Butte, suggests an earlier folding and erosion
along the same line,

The next important area of Payette exposures is to be found about
Willow Springs in the Send Hollow district. Here the Eocene is largely
sands and shale, distinctly unconformable with the overlying Idaho. A
contact is observeble a quarter of a mile west of Willow Springs, and
shown in the sccompanying photograph; the Idaho beds here dip 14° west
end the Payette 5°N,E.

On Vale Butte the Payette is represented by buff, fine grained,
massive sandstone, and is exposed on the west side of the butte. The
contact between the Eocene and Pliocene, which caps the butte, was
taken as a sharp even break occuring at an elevation of 2640 feet. The
thickness of Payette exposed is about 150 feet and is made up entirely
of sandstone.

Along the eastern side of Willow Creek Valley, a faint unconformsble
relation can be made out in the beds for a distance of 7 or 8 miles
above Vale. This occurs near the base of a high ridge forming the east
side of the valley. The lower beds are shale, and the overlying corres-

pond to the Idsho. This contact runs under the Idaho coverinc 7 or 8

miles above © vy 1 whi At # . .
Vale , beyond which to the foothills the Fliocene Pre-

 

  
  

Fin
dominates. In the foothill district the only exposures that may be re-

ferred to the Payette are made up of acid and basic tuffs lying beneath
the Idsho unconformably, and not showing the induration observable in
the fre-Tertiasry rocks.A basalt flow was shown in a small exposure in-
terbedded in thin banded basaltic tuffs. These tuffs occur in detached
areas along the foothill belt, and are found in Cow Valley, but the
relations between the tuffs exposed in Cow Valley and those found to
the east beneath the Idaho beds sre obscured by later lava flows and
feulting along Road Cenyon. Their similarity in appeerrance would lead
to the conclusion that the tuffs in the two places were identical.

PAYETTE VOLCANICS.

Aside from the heavy lave flows occurring in the Owyhee Canyon, and
which appear to form the base of the Payette as exposed in this ares,
other evidence of volcanic activity is to be found associated with the
Eocene. About Mitchell and Chalk Buttes basalt flows are intercalated
in the Fayette beneath the Idaho contact, forming a horizon in the Pay-

n Basin distriet flat ly-

a

ette higher than the Owghee lavas, In the Xe

ing basalt flowscep the slightly folded Payette beds, and appear to

{J

have formed in the intervel between the Payette and Idaho.

AP Willow Springs a flow of basalt about 60 feet thick is imbedded
in the Payette; it mounts upwards and ascends the western side of the
Double Nounteins. So far es the writer's pbservations extended, this

range is made up of rhyolite and basalt flows, and from the relation

®

oO
Q
a»
=
ow
o

to the Payette flow given above, appear to be of ge.
‘he Juniper Range, which forms the western side of Willow Creek
Valley, is made up largely of lava flows. Only the southern and northern
ends of the range were visited. On the south are heavy basalt flows

covering the Idsho beds. In Cow Valley, at the north end of the range,

are folded basaltic tuffs similiar to those observed further east beneath

the Idaho formation. The tuffs in Cow Valley are overlain by thin basalt

   

 
 

718
flows here referred to the Fost-Pliccene flows occurring in the

foothills, The tuffs were slightly folded before the last outflows of
basalt, which,together with their similarity in appearrance with
those beneath yhe Ideho formation eesstward, would lead to the in-
ference that they were identical.

Juniper Mountain, on the south side of Cow Valley, forms the
northern part of the Juniper Range and rises to an elevation of 6500
feet as determined by an aneroid. The following section was taken
up its northern side: |

l. Elev, 4600 ft.- Top of Pre-Tertiary shales.

2. To elev. 5270 ft.(670 ft.) are grayish massive coarse tuffs,
carrying numerous small glass fragments and larger chunks of basalt
near the top.

3. Black columnar basalt flew, 10 feet thick.

4, Elevs, 5280-5600ft.(320ft.) Pink weathering basic tuffs, with
an interbedded layer ¢f ¢! finer black ash. Lava fragments throughout.

5. To elev, 56560ft. a steam blown flow of grayish basalt.

6. To elev, 6500ft. are alternating basalt flows and beds of tuff.
It is thus seen that the volcanic material exposed on this mountain is
about 2000 feet in thickness. In addition, several wide basaltic dykes
were noted in the ascent, showing a vertical platy structure due to
flowage.

The relations between the tuffs in Cow Valley and those on this
mountain were not worked out, the relations being obscured by faults
along the northern face. As already mentioned, the flows in the south-
ern portion of the range overljyeIdaho beds, and similiar flows extend
down the northeastern flanks toward Willow Creek and comer the Pliocene.
Considering the nature of the ash and flows on Juniper Nt., and the
large dykes of basalt found in the volcanic series suggests that this

rti f 2 , 2 3 upd -
portion of the range was a seat of volcanic activity following the .

 
 

419
128no end probably in earlier periods as well.

IDAHO FORMATION.

 

According to Lindgren's observations, the Idaho beds represent ;
a deposition during & halt in the subsidence of the Payette lake. This
was & reasonable hypothesis when the Payette was regarded as of Miocene
age, but with an Eocene age it is hardly tenable, for it is difficult
to understand how & body of water would remain for a period like the
Miocene without deposition, as mentioned by him in Folio Neo. 103.

Russell (Bull.zl7?7, pp.63), mentions lake beds west of the territory
covered by this paper, at Beulah, which, from an incomplete list of
flora collected by himself, end determined by Dr.Knowlton, represents
eg deposition younger than the Psyette(with an Eocene elassificatien)
and correlated with the Mascall or Upper Miocene formation in the
John Day region. Another occurrence of probable liiocene is mentioned
in Bulletin 199, where verterbrate remains were collected in Owyhee
Co. Idaho. Regarding the fauna described, F.A.Lucas writes:" the above
«+... meager data seem to i belong to the liiocene
and Upper Pliocene, but at present it is impossible to draw a line
between the two." (seepp.56)

The contact observed between the Payette and Idaho by the writer
is shown by the following photographs. In the vicinity of Mitchell
Butte and Willow Springs it is an angular one, but about Vale it is
& sharp even break between beds of san8stone of & similiar nature. In
this vicinity, irregular places occur along the otherwise even line,
and such depressions are filled with small pebbles and current bedded

There is also a variation in altitude at which it eccurs.

On Mitchell Butte it is found at an elevation of 2780 feet, but a mile

east and north it occurs several hundred feet lower. At Willow Springs
 

 

 

#19a

——————— es
Hrs
—————

 

Eastern portion of Mitchell Butte
viewed from the south.

 

Unconformity between
the Payette and Idaho,

near Willow Springs.

 

Unconformity between the Payette
and Idaho a mile east of Mitchell

Butte.

 

Unconformity between the Payette and Idaho
on the Owyhee River, eest of Mitchell Butte.

 
#20

It lies at 2600 feet; along the south bank of the Malheur River and on

Willow Creek at about 2300 feet, while on Vale Butte it is found at
an elevation of 2640 feet. Whether this variation in altitude is
due to the origional topography of the surface, or to subsequent move-

ments, is not clear at present.

The Idesho formation as found in this area caps the highest buttes,
which ofter rise considerably above 3000 feet. The beds are largely
shee and sand, closely resembling the Payette exposures. Tuffs are
limited, a few layers only of white ash being noted along Willow
Creek,

The Idaho was traced in this field by characteristic

persistent over wide areas.

The Puddingstone Zone is the lowest series of such beds. It is
separated from the Payette contact by a variable thickness of strats,
usually a fine white sandstone like sugar in appesrrance, from a few
feet to over 100 feet in thicknes The zone itself is made up of
layers of smell round pebbles, alternating with finer sends, the grad-
ation between the two being rapid. The sandstone beds are as much as
20 feet thick, while, with local exceptions, the gravel layers are
under 6 feet. The gravel beds are made up of cherts, gquattz, slate
and other hard rocks, although some fragments resembling rayette shale
are found. The absence of basaltic pebbles is noticeable, The pebble
beds are exceptionally hard end indurated as a rule, weathering reddish
brown. A bed about 10 feet thick was noted about Liitchell Butte in
this zone made up of coarse sands with crossbedding inclined at high
angles to the northwest.

Near Dell on Willow Creek, the fuddingstone Zone is represented by

£21

& thick series of sands, some of an angular nature; pebbles are here
scarce. This zone is sbout 300 feet thick.

The Calcareous Zone is the name applied, in the writer's notes,
to a thick series of shale, sometimes sandy, of a calcareous nature. It
rests upon the Puddingstone Zone. The calcareous materisl is represented
by thin seams of white lime in both vertical and horizontal layers, and
&s a cement for the shale and sandy shale,

On Mitchell Butte this zone is represented by 300 feet of sandy
limestone, more calcareous toward the top. It is capped on top of the
butte by a layer of pebbles similiar to these of the ruddingstone Zone.
iest of Chalk Butte and southeast of Vale Butte the Calcareous zone is
characterized by calcareous shales, with seams of white lime.

Above Dell, as in the case of the Puddingstone Zone, it is represent-
ed by finer meterial, made up of white chalky limestone, sometimes sandy
but generally quite pure.

In the Big Sage Flats, southeast of Vale Butte, the Calcareouf Zone
is overlain by 300 to 400 feet of small pebbles and evenly bedded sands,
in alternating beds of considerable thickness. The pebbles are largely
basaltic, in contradistinction to the pebble beds of the Puddingstone
zone where basalt pebbles are rare. A somewhat similiar zone is re-
presented alomg the foothills north of Dell. This caps the Calcareous
Zone, and is made up of 200 feet of brown mud and clay of a sandy nat-
ure, with lenses of red basalt gravels. This portien eof the Idaho, if
it can be referred te that subdivision, encroaches over the bedrock
series of the foothills, no evidence of the lower zones being noted with
in the foothills themselves. This suggests an encroachment §f deposit-
ion from the south.

While the Idaho beds are supposed to be of lscustrine origin,
the nature of some of the layers, especially in the Puddingstone Zone

and those above the Calcareous zone, points to g fluvatile origin for

 
i222

. fragments
at least a portion of the series. The occurrence of Payette shale, with

the round hard pebbles of the Fuddingstone Zone, suggests rivers coming
a considerable distance, and flowing over & country made up of earlier
Tertiary sediments. There was probably & fluctuatien between fluvatile
and lacustrine conditions in ths Idaho, and toward ths later stages
important changes must have occurred in the tepography oEuin geolog-
ical events whereby the large amounts of basaltic material was brought

down, snd deposited with the sands over the Calcareousnzone.

THICKNESS OF THE TERTIARY SEDIMENTS.

The thickness of the Payette formation is not determinable from the
informatien at hand, but the Idaho can be placed between 800 and 1000
feet. A wekl along the Snake River, at Payette, Idshe, is said te have

penetrated 2600 feet of soft sediments without passing through them.

PLIOCENE VOLCANICS.

Fo lava flows were actually encountered in the Idaho formatien,
but Lindgren states that it is charscterized along the Snake River by
thin basalt flows. Russell alse notes the same occurrences.

Looking 7 or 8 miles easterly from Willow Creek Valley. layers of
what from a distance resemble lave flows can be seen intercalated in
the Ideho beds.

East of W.J.Scott's ranch on Willew Creek, & few beds of ash several
feet thick were encountered. The ash is rhyeolitic, and eccurs imbedded
in Idaho shakes.

Between Vale and Ontarie, at lialheur Butte, a large intrusion ef
basalt hes broken through the Idsho, hardening the beds about its peri-
phery, and giving them a domed appesrrance. The mass is a quarter of
g mile in diameter, and accerding te Russell (Bull.252,pp.30.) it bs
an old volcanic neck intrusive into the Payette; the writer's observat-

ions would place the beds as Idaho.

Foz

Basalt dykes are alse found cutting the Idahe fermatien in upper
Dry Gulch, a valley about 6 miles east ef Willew Creek.

In the feothill regien are bread flat tepped tablelands capped with
basalt flows. These flews are of wide extent in this district, and
cover beth the Pre~Tertiary recks and the Pliocene sediments. The lava
cap is made up of seversl flows aggregating 50 te 150 feet in thickness.
They occur generally at an elevation above 3000 feet, but they do not
extend down Willow Creek Valley as far as Dell. The general elevation
of the country south of the foothills where these flows occur is lower
than the tablelands, and it is difficult to state how far south the
flows extended and been sulBsequently removed by erosion.

An interesting relation is shown in Willow Creek Canyon near the
mouth of Mormon Rasin Creek between the pre-lava and the present top-
ography of the country. In the canyon and a small tributary from it,
both of which are cut in the Pre-Tertiaty rocks occasional masses of
basalt are found. These show show a radiating columnar structure per-
pindicular to the walls of the canyon, and at one place a layer of
basaltic tuff was found on a terrace in the gorge. These lava masses
do not appear to be dykes, but rermments of extensive flows, and are
similar to the basalts forming the pablelands. The hypothesis offered
is that the region had been sut into a2 topography somewhat similar to
that of the present daybefore the later outpourings of basalt. These
flows filled up the o0ld drainage, and in the case of Willow Creek the
new stream has cut out the 0ld canyon again, and only a little deeper
than the older one. This, together with the fact that the basalts rest
on the older rocks and the Fliocene alike, end im places where the
Idsho would be expected to be found, suggests that considerable erosion
took place following the Ideho and Preceeding the lava flows.

At several points on the high ridge along Road Canyon are detached

portions of a pink rhyolite flow about 10 feet thick. This {4 Someting
’ w oLOeLlNNes

 
 

£24

underlain by an equal thickness of white ash, generally massive. These

overlie the Post-Idaho basalts.

TAM N 'T DRMATTM
QU AT ERNARY AXD LG ENT *

 

-

age of the deposits here referred to the Quaternary is by no

means certain, The deposits are later than the Idaho, and it is for this
reeson that they are assigned to the Cenozoic.

Along the Owyhee River, and forming a terrace, occurs a bed perhaps
10 feet thick of gray weathering gravels and cobbles mostly basalt. This
is overlain in places by silts and clay, merging into soil. The layer
oceurs at almost a constant evation of 2250 feet, 1 extends from
the Owyhee River Valley, along the western side of
and into the lalheur River Valley.

What mey represent still an earlier Quaternary posit oceurs in the
Big Sage Flats at an elevation between 2500 end 2700 feet. Here, overly-
ing the grevels and sands of the uppermost Idsho formation, is a bed
10 to 15 feet thick, made white lime resembling travertine form-
ing a matrix for numerous gr , and cobbles of basalt, granite, black
rhyolite, etc. Thi plcareous deposit is associated below er above
with a bed of the same sort of gravels ut without the cement. These
beds ar ‘ormable with hc ut resemble lithologically the
gray gravels at a lower elevation.

ore recent deposits of silt and clay occur in the valleys of the
Owyhee and Malheur; they
tent slomg the valley floors. They show even lamina’

ably fldod plain deposits of the present streams.

Evidence of recent volcandbc activity is to be found in Cow Valley,

Tmbedded in the soil of this wide depression, a foot below the surface,

#25

is a thin deposit of pure white ash. It is about 2 feet thick, end in
the western part of the valley, near W.D.Watt's ranch, the valley has
been eroded 10 or 15 feet below the ash bed, which cen be traced for a
considerable distance along the side of the valley. A similar occurrence
was noted by Prof. llerriam in the John Day River Canyon (Bull. Dep't.

of Geol., Univ. of Celif,, Vol. 2, No.9, pp. 314), and the ashes may be

contemporaneous.

DEFORMATION.

The deformation to which the Tertiary sediments hewebeen subjected
is considerable. There is evidence of folding and faulting after the
Payette, and some folding end considerable faulting after the Idaho.

The strike observed in the Payette is generally northwest to south-
east; that in the Idaho about north and south. The Idsho folds show
more of a doming effect, the anticlines not being continuous. From the
occurrence of doming observed near the basalt intrusion into the Idaho

ilalheur Butte, this structure elsewhere in the Pliocene beds may be
to the same cause, the intrusions not reeching the surface but form-
laccoliths.

The chief movements appear to have followed the Idaho and ceased
before the deposition of the Quaternary bench found n elevation of

feet, but that there has been deformation subsequent to this is

shown by the warped lave flows of upper Willow Creek, and the occurrence

 
   

#26 5
PETROGRATHX.

The rocks described below are from slides taken from single
specimens, and for this reason are not to be considered &s represent-
ative of the mass of rock from which they were obtained.

COW VALLEY BUTTE QUARTZ DIORITE.

In the hend specimer this is a coarse grained rock, ome third of
which are hornblende and biotite, and the remainder gray feldspar
and quartz. The feldspar predominates over the quartz. The greater
nunber of feldspars sre idiomorphic, and often striated. The biotite
averages about 5mm. in dimensions, the other constituents about 3mm.

Under the microscope the texture proves to be hypidiomorphic
grenular. The biotite is the brown veriety, and predominates over the
hornblende, which is green. Both are idiomorphic; and the biotite is
altered to some degree to chlorite.

Plagioclese is the most abundant feldspar. Zonal structure is
common, becoming more acid toward the periphery, but showing a var-
jation in the growth of the more acid and basic constituents. One of
these was obtained perpindiculer to I , and showed an angle of 48 ° be-
tween the (001) cleavage and the axial plane at the center, and 45°
on the outer zone. This corresponds to Amorthite, Abq14n544. Tumerous
ijdiomorphic plagioclases occur, generally twinned after the albite law.
Sections perpindiculer toAshow an inclination of 69 © th(010) cleavage.
This corresponds to Andesine-Oligoclese. These feldspars are older than
the zonal ones, sometimes being included in their borders. Some idio-
morphic feldspars show both albite and pericline twins, with a maxim-
um extinction of 13°, and are either licrocline or Andesine-Oligoclase,
but their number was not sufficient to determine exactly in the slide
examined, In addition to the above, several allotriomorphic grains were
noted with a small extinction angle and no twinning; they are probably

orthoclsase.

The queftf)z is in considerable abundance, an

always &llotriomorphie,

 
    
  

Accessories noted are apatite and magnetite in small amounts.

The feldspars are generally cloudy; some muscovite occurs in the

more acid ones alohg cleavage cracks and fractures, and appears to be
& secondary constituent.

The order of crystallization is as follows: magnetite and apatite;
biotite and hornblende; oligoclase-endesine and Wiecrocline(?); anorth-
ite + .; orthoclase; quartz.

The slide corresponds to a quartz-mica-diorite; but the rock has
been referred to as granite in the paper es there is no reesson to be-

lieve that the slide is typical of the bulk of the rock.

Intrusive Sill id theTRIASSIC OF COW VALLEY BUTTE.

This is & fine grained rock with a greenish cast. Nimerous needle
like hornblends are discernable, everesging 2 to 3mm. in length. Other
constituents observable are & small amount of dark quartz, amd striated
feldspars, and other feldspars of no definate shape.

Under the microscope, the hornblende has & green-brown color, and

is often replaced by chlorite; chlorite also occurs in & few areas

7

suggestive of biotite, but no origionel mice was observed.

1

The feldspars predominate somewhat over the hormblende. It is both
idiomorphic and allotriomorphic. The former proves to be striated plag-
ioclase, giving e& maximum extinction of 26°against the trece of the
composition face (010). This corresponds to labradorite, Aly An The
allotriomorphic feldspar is rarely jwinned after the Carlsbad law, and
invariably shows an even zonal extinction. The outer portions extimguish
at small angles to the cleavage, while the inner shows a higher inclin-
ation in the position of the elastic ames to the cleavege. It probebly

represents a gradation between a sode feldspar and orthoclese. The

feldspar is more or less cloudy, and the labradorite predominates over

the alkali feldspars.

   
 

  

  

 
  

£28

Epiodote occurs in & few crystals. It is recognized by its color
and yellow pleochroism, high refraction and double refraction, ang form.
Cleavage is well developed parsllel to (001), and to a less extent
parallel to (100). It is sometimes associeted with chlorite, but usual-

oacurs
1y sthroughout the section sometimes enclosed by feldspar. It appears

Po

constituent.

1

giona

wr

to be an or

A Tew quartzes are present, and are &lliotriomorphic in form. A
little iron are is slso present.

This rock, which has an A¥pidiomorphic granular sfructure, occurs
a8 & 8ill esbout 12 feet thick in the Trias of Cow Valley Putte. It is
presumably connected with the granitic intrusion there exposed. The
slide corresponds to & quartz-diorite; but considering the amount of

alkali feldspar present, & granodiorite application might be justified

om

if the quartg were in larger amount.

APLITE, COW VALLEY BUTTE.
This is & white, fine grained granular rock, in which quartz, ortho-

clase, plagioclase and some biotite can be detected. The average size

Under the microscope it is seen to be & holocerystelline aggregate

~ ~ a 1 . 2D € : No < J ~ 2 a 3 Lb 1 3
of quertz, orthoclase, plagioclase, and & little tiotite, muscovite
and zircon. large crystals of quartz snd feldspar occur in prevailing
. - c J haces a A mp n 1 - Ter 3 0m . ih & od
smount, and these are separsted from one another by finer asggregates of

A vv ey n Pant the tevtnre crocesta +ha f a oranite nor
porphyry. In fact the texture su gg ests that of = granite por

A vn -~ Y 2 “oy Vr ny Ir v C 1" © YT ¥ 2 S “Tn ¥ § 4 co T4 ~ ~ 3 ~T & "1 .
AOR Z the larger ystals quartz predominates. LIU 18 01 1rregulerx
~~ €3 V i nn ar etal 3 oo 3 - > La -
shape, anc each crystal is mede up of several individusle differently

-

orientated.

Mh a PaoTlAdAorearos ohh AY "1 = yy A 1 ah AN mr mS ee Mh a - =
LIIe IelLaSpPars Snow albite an Carlsbad Winning 'he larce ones
</ CL ee

 

are usually cloudy on the interior, but fresh on +he I

 

29
The orthoclese:, which is the most abundant feldspar, shows a tendency
toward idiomorphism, but mot so much so as the plagioclase, The orthoc~-
lase's period of crystallization laps over into that of the groundmassy

for the borders of the alkali feldsper generally include portions of the

groundmass crysta

af

8, end there is a rapid gradation between the two.

fete

m1 ~ 1 ~
+e DLE SLE

0

tS
Q
w
®

lase 1c geherally idiomorphic and twinned after the albite
law. The maximum extinction in zones perpindiculer to the (010) face
is a few degrees, showing the plagioclase to be Cligoclase.

The larger crystals descrited above are separated from one smother

rt
Ls)
=
on
pt
Oo
ch
+
Pie
oO
KF
oO
=
=
gp?
¥
pte
Q
on
oO ®)
o
Sie)
4Y]
ei
pe
oO
b ’
Oo
Hh

feldspar and quartz which form the

the growth of one another. Quartz and felds
portion, and the latter are mot cloudy like the large feldspars. The
rthoclase, but & few with
idiomorphic tendencies occur, with albite twins snd smell extinctions

e 1s the brown variety; it occurs in scattered foils

de
3

limited amount. The muscovite occurs in foils and rosettes in the feld-

rv = wes pd o 4 BD 3 -y ey vy \ A 4 CS mn at 2

spar, and appears to be a secondary product. Some few foils are to be
fou nd in the ground nass rnressed in between the ome 7 an + A a 0
found in the nomass pressed 1m between the quartz ard feldspar, and

is probably a primary constituent.

This rock occurs im thir dykes in the granite of Gow Velley Putte.

-} @ "ep “vd 3 cac We farmed: +he aarl3 ” : :

the larger orthoclases were formed; the earlier generation is represent-
1, oa ret alar Fhe Tater her +e coe v; i
the large crystals; the later by the groundmass

The mineralogical constituents end occurrence corresnond to an

    
        

   
   
    

4 3
roe
LAMPROPHYRE, COW VALLEY BUTTE.
This rock forms smell dykes im the granite of this butte, and is

confined to the peripheries of the intrusiom. It is a fine grained green-

Hy

ish rock; the greem cast is due to numerous small areas of chlorite. A

little quartz can be recognized, snd numerous feldspars of a& gray cloudy

color. The structure, other than the rock is holocrystalline, is difficult

@

to determine in the hand speciman.

liicroscopically examined it is seem to be made up of cloudy feldspar
green mica, & little quartz, and mich chlorite and calcite. The rock
is guch decomposed.

The feldspar occurs both idiomorphic amd allotriomorphic. The idio-
morphic omes show Carlsbad twins, and rarely albite twims. Zonal ext-
inction is common in these, desressing from & maximum of 30°to the (010)
face

Lo 0°to the seme pinacoid. A few idiomorphic plagioclases occur with
slbite striations, also; the maximum extinction in the zone perpindic-
uler to (010) wes 25°to the twinning planes; this corresponds to lab-
radorite, Abj&n,. The most predominant feldspar shows a tendency toward
idiomorphism, and generally is twinned after the Carlsbad law, which,
combined with small extimction amgles,show it to be orthoclase. It is
filled with derk dust arees, end ineludes titanite, muscovite, apatite,
and chlorite. Other orthoclasees occur in irregular areas, completely
surrounded by decompositiom products.

The quartz is conspicuous and freeof inmcl@isions. It crowds about
the other constituents, from which it is not sharpely defineé; most of
it has no definite shape and sppears to be secondary.

The calcite occurs in irregular aress intimately associated with the
chlorite; some masses suggest a replacement of em idiomorphic feldspar.
A few grains of dust laden epidote occur, most often with the chlorite.

Other minerals noted in sparing amounts were apatite, titanite,

and magnetite. The origiomal rock appears to have been a minette

31

  
  

The chlorite sometimes has the appearrance of having repleced biotite,

and for this reason, the term minepte is proposed.

BASALT DYKE IN THE GRATITE OF COW VALLEY BUTTE.

This rock occurs as a dyke about 20 feet wide in the granite, and
is traceable for several thousand feet. It is a mouse colored rock
with fime ever banding =2lonmg the walls, probably due to cooling amd flow-
ing when intruded. The only comstituents observabable im the hamd spec-
iman are mumerous minute feldspar needles and dark brown crystals of
pyroxene,

Under the microscope it is foumd to have a hyalopilitie structure;
crystals of feldspar, pyroxene and irom ore imbedded im an equal amount
of brown glass, mekes up the slide.

The feldspar occurs im long frayed out crystals, invariably twimmed

after the albite law, and in addition, some with Carlsbad twins. They

0

are generally fresh. The maximum extinction oltained in the zome perpin-
dicular to the(010) face was 30° corresponding to basic labradorite,

but the method of li.Levy showed them to be amorthite, Ab, 4my,,. This
probably shows the correct determination.

The pyroxene is about as plentiful as the feldspar. It is of a gray
color with & green cast, and the cleavage is not well developed. The
greater proportion of it shows the high extinction and double refraction
cf augite; but a few occur with sharp crystal boundaries, with low
double refraction, parallel extinction amd a pinacoidal cleavage; these
are an orthorhombic pyroxene, and from the very slight pleochroism are
referred to hyperstheme, The crystallization of the sugite and feldspar
hes been overlepping, 2s some augite is older than the plagioclase
while some is evidently later,

Much magnetite is present as a primary constituent, and also a little

zircon, No olivine was detected. The rock corresponds to basalt.

 
 

 

#32
DACITE NECK, NORTH OF ROAD CANYON.

At first glamce this rock has the appearrabce of a diorite, but clos-
er examination showsit to comsist of crystals of plagioclase, quartz and
a decomposed ferromagnesian mineral set in a finer groundmass.

Under the microscope, it is seen to have & porphyritic texture, the
phenocrysts, which form about half the rock, being separated by a felsit-
ic groundmess.

Quartz occurs im round grains of large size, the periphery being
marked by & thim band of crystals which appear to owe their formation
to resorption of the quartz into the magme. Many of the quartz crystals
are made up of two individuals, joined along a rather even line and d4if-
ferently orientated. The imclusioms are few and include small dust pat-
ches and zircon.

The feldspar predominates over the other constituents. It occurs
both as well defined crystals, end as more or less resorbed irmdividuals.
Some show zomal structure; albite twins prevail, although some of the
plagioclases in the zone perpindicular to (01Q) show no twinning. The
relations between the resorbed and well defined feldspars are interest-
ing. A resorbed crystal was obtained perpindicular tol ;the angle be-
tween the axial plane and the (010) face was 75° corresponding to and-

iine-o0oligoclase. Another well defined crystal was obtained with the

“

e

0

seme orientation. The angle between the axial plane and the (010) face

t
was 64°, corresponding to a feldspar between andesine and sodic labrsd-

orite. It was noticed that the least resorbed crystals had the greatest

Y.. ian hung . 1 wr ~ ~~? dtm de an "A . nd
neétween tne extinctior ne uter and 1unner portions.
mh a v1 a os 3 md a ahr lant and have heen ent er v =
"he dark constituents are apbunaanit, anc 18Ve pec tirely renls ced
Tawr CUZ PAV A ETT VAT AYA OV wr SHADY heave heer aT ; :
by secondary products. They appear to have been origionally augite and

$33
dust, calcite aggregetes, and & bluish green roughly fibrous substance.
The fibres are roughly perallel to the verticel exis of the host, and
show the following pleochroism: perpindicular to the fibres, yellowish-
green; pergllel to the fibres, bluish green. The double refraction is
upper first order, end the extinction parsllel; the index is greater

A

than thet of balsam. Iddingsite has & higher double refraction, and

the mineral is probably a chlorite.

A + x7 -r a CY cod } € Te oh ma bo 2 ha

A few badly resorbed crystals that have certain properties analogous
to zoisite occur: index high; cleavage poor, but fractured like apatite;
biaxial; axisl plane perpindicular to the elongation; parallel extimect-

ion; double refraction less than that of quartz. A small isotropic pink

-

crystal with round outline was observed, snd resembled garnet. A small

amount of iron ore and apatit

P»
0
H
®

present.

The groundmass is made up of a little glass and much minute feldspars

with irregular shapes. Some show & tendency toward crystal boundaries,

and a bagel section of one, measured after the method of Becker, gave

£2 2 5 3 s - © > " -

an extinction of 26", corresponding to sodic labradorite, Ab
This rock corresponds to & dacite. It occurs as a stock or neck of

considerable size, intrusgkve into the Trias of Road Canyon.

POST-IDAHO RHYOLITE FLOW, ROAD CANYON.
This occurs in limited patches overlying the Post-Idsho basalts in

bout

ao

this vicinity. The flow is 10 feet thick. It is a pink lithoidal
rock in which a few phenocrysts of glassy feldspar can be detected. Im

the hand speciman, & small piece of dark colored quartz wes noted. The

. ela © + ~ 1 $n $ vm
crystals are under 2mm. in size.

Microscopically exambned, it is seem to be made up of a large pro=

~

"oT \ £ or 88 11 yf rar 1 1 A ot anA ala tre oer
portion of glass full of red irom dust nd showing a well developed

The feldspar is both we I 3mA irra tev
» © i ll defined and irregulsr in Shape. The latter

 
#34
ones are fresh and have & small extinction and axial angle, correspond-

ing to sanadine., It is sometimes twinned after the Carlsbad law, The

ganadines are more or less resorbed. In about equal amount are the more

idiomorphic feldspars. These invariably show a very fine twinning. One

crystal was made up of broad lamellae, which extinguished to the right

and left at 89;each of these broad lamellae was made up of very mueh finer
guished slmost at 0°. A very finely twinned

obtained perpimdicular tol, and the axial
and from the nature

3 * 1 & Yr One nT rr a] ¢ MSM MT
sometimes irregularly intergrown with e¢ sanadine.

groundmass is filled with ferric oxide dust; it has well develop-

The g
ed flow lines eddying about the phenoecryst: 'he flow lines are charact-
ce of dust, and show an incipient developement of the

occur
Irregular greins of iron ore occur, generally surrcunded by an ochre

*

$n ye AY ma ~ CEN E 3 - CX YY) £3 »
decomposition product. The association of small areas of

yeddowish, strongly be a titanif-
erous magnetite.

Fo quartz was
found in the kand speciman : ity of quartz, combined with the

it is on the border

£35
AUGITE ANDESITE, ROAD CANYON,

This speciman wes obtained from a thick flow exposed along the

canyon road, of Tertiery age. It is a bleck rock, with large light
amber colored feldspars about 1#x5 mms. in dimensions, and a lesser

number of black pyroxene. Irregular cavities oceur lined with a bot-

ryoidal iron ore of a wine color and vitreous luster.

Under the microscope the comstituents are seen to be remarkably fresh.
The rock has a porphyritic texture, and is made up of large grains of
pyroxene and feldspar crystals set in a minor esmount of brown glass
filled with a feltwork of lomg brown trichites.
The feldspar includes both andesine and oligoclase. The determinations
based on the method of Fouque. The pyroxene occurs in large areas
is & a grayish brown augite; it is slightly less in abundence then
feldspars. The augite followed the crystallization of the andesine,

was contemporaneous with or preceeded the oligoclase.

The andesine is the predominating feldspar; it is twinned after

the albite and Carlsbad lsws. The oligoclase is rarely twinned, end is
distinguished from orthoclase by the fact that its index of refraction

is & little greater tham that of balsam. A few crystels showed zomal
extinction, with andesine on the inside and oligoclase on the borders;
but as a rule the two feldspars form seperate crystals. Some of the olig-
Oclases show & gradation between one face and the groundmass, as if the
the source of its formation were suddenly exhausted.

liagnetite was the first to form from the magma, amd it occurs in
lerge square crystals throughout the section.

In the groundmass are small irreguler crystals of a bluish green
color. They are isotropic, with a refractive index lower than 1.54; some-
times a good square cleavage is developed.This corresponds to fluorite,
and if so is an interesting developement of this mineral.

The slide examined coincides with an augite andesite.

 
£36

HYPERSTHENE BASALT NECK OF MALHEUR BUTTE.

This rock forms a large mass which has been intruded into the Idaho
beds between Vale and Ontario. It is fresh looking, of a brownish black
color; numerous minute plagioclase laths are discermable, as well as a
little iron ore.

With the microscope it is seen to be made up of numerous plagioclase
crystals set in a groundmass of grayish glass. Other constituents noted
are pyroxene and magnetite.

The feldspers are of two sizes, large and small, although there is
& gradation between them in size. The large ones are all roughly orient-
ed in a common direction; they are fresh, idiomorphic, some a little
resorbed, and generally fractured at right angles to the elongation.
Albite twins prevail, and Carisbad sre rere. The maximum extinction
obtained in the zone perpindicular to (010) was 28%, showing them to be
labradorite Ab An,. Some show & zomel extinmtiom, becoming more acid

+ 9
toward the periphery. Inclusions comprise a little glass and magnetite.
The core of one large crystal was made up entirely of a substance re-
sembling the groundmass, but of a lighter color; under crossed Nicols
this portion resolved itself into & series of albite twins, which coin-
cided with those of the feldspar forming the borders, but was of a less
definite nature.

The smeller feldspars, which range down to mimute size, are generel-
ly arranged about the larger ones in such a way as to
They are not fractured like the larger omnes, and probably represent a
later generation, Otherwise they correspond to the larger ones im all
respects. A section perpindicular to the elongation was obtained of eo
very small one; it gave an extinction of 37°, corresponding to labrador-
ite, AbzAn, , according to the method of Becker,

The pyroxeme occurg in sparing amount; it is sharply defined, of a

light gray color, low interference colors, parallel extinction and

t37 | ;
a prismatic and sometimes & pinacoidad cleavage. A section almost perp-

indicular to the prismatic cleavage showed the emergence of an optic

axis just outside of the field, showing the angle between the L axis

in
and the optic axes is not as large as \ferruginous hypersthene. On ace=-

ount of the very slight pleochroism, the pyroxene is referred to hypers-
thene; the species in the rock is probably intermediate between enstat-
ite and hypersthene.

Magnetite is abundant and occurs in small grains throughout the slide.

Ocourring in considerable abundance in the slide are small areas of
transparent glass associated with a roughly fibrous substance that has
the following properties: index of refraction greater than that of bal-
sam; elongation in the direction of least elasticity in all cases, sug-
gesting a uniaxial mineral; double refraction lst order yellow; pleo-
chroism, parallel tp the fibres, brownish yellow, perpindicular to then,
light yellow; extinction parallel. These fibres are orientated in all
directions, so that complete extinction is not to be obtained in all
cases, Sometimes the fibres occur in patches in rounded glass grains:
again they are found with glass of the same color as the fibres and this
shows a series of oracks intersecting one another about at right angles.
Throughout the slide are some minute cracks filled with a mineral of the
seme character, the fibres where observable being traverse to the walls.
Where these have cut the feldspar, larger areas have formed along the
cleavage cracks replacing the feldspar. In fact some of the areas of

the brownish gless have sa shape suggestive of feldspar. This mineral

has some resemblance to lucoxene, but it agrees entirely with none

known to the writer.

This rock appears to be on the border line between the basic

andesites and basalts. It is referred here to a hypersthene basalt.

 
 

PALAEONTOLOGY

 

The palaeontologicel work so far dome om the formatioms of this
region are incomplete. The following forms have been reported from the
Palaeozoic: Roumd cerinoid stems, Productus sp., Spirifer sp., re ported
by Lindgren; Zaphrentis sp. reported by Washburne.

In the Triassic, Lindgren mentions the following: Halobia sp., Tur-
ritelle sp. or Pseudomelania sp., Doamella sp., Lima sp. Aviculopecten
sp. has been reported by #Washburme.

They Sayette forms are limited to flora, and need not be given here,

but Lindgren mentions the fallowing fauna: Anodonta sp., Gomiobasis sp.,

‘hysa sp., Tulotoma sp., Sphaerium sp., Corbicula Sp.

Phe Idaho formatiom has yielded verterbrae of fish and mammals, and

the following faunme: Umio sp., Gomiobasis sp., Fhyse sp., Valvata sp.,
Ancylus sp., Flumimnicole sp., Sphaerium sp., Corbicula sp., Lithasia
antigua Gabb, Latis dalli White; the above have been reported by Lindg-

ren. The following have been reported from the Tertiery lake beds:

 

Carnifex (Vorticifex) bimmeyi Meek; Sphaerium(?) idshoense leek; lel-
enie taylori Gabb.
The writer noted Unio and Anodonta fragments frequently im both the
Peyette and Idaho; and some water worm wood fragments im the Payette.
The following were collected and determined:

Coarse sandstone, bese of Nitchell Butte: Carnifex sp.; a small

 

Spheerium; Unio spi; & compressed gasteropod, Fluminmicols (?) sp.

Base of the Idaho, Mitchekl Butte: Carmifex(Vorticifex) bimmewi

 

leek; Sphaeriumfidahoense leek; small forms resembling Lithasie antique

 

Gabb; this form is common in the Idesho in this region and resembles

Gabbs specimen only being smaller.

 

Celcereous Zone, Mitchell Putte: lielania taylori Gabb; Sphaerium(?)

idehoense leek,
= Maps 76 Fccompserny
| Garlogy of Loti, frson

<. 4. Lches / 904,

 
TE fT ASE

AT #6 £
eric 1s West of Greer wich

 

wlMalhewur City ’ 17°70’
20

ORL G PV SOAHO

 

: Huntinghon
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VALLEY

.
“tts s agent
.

 

 

 

 

 

 

 

.
.
.

 

 

THESIS, &£tL./cHES,/909.

Compiled From local maps and
observa tions »» he fre/a, /1908

Contours and contacts of shelch valve

0s2/y.
[1] ALLL viv

IDAHO Formaili/on
generally Sand and Shale NES . Z 3 = nif

 

 

7
Seca le 250000

Pliocene
Fleyations b 0y Hnercrd Barom.

PAY ET TE Formation. Contour 1nferval 250 ft
Sand, shale, 7eff
Eocene ’

 

IN

T7/IARY

V4
7

TER

: y Mathes Botte

LAVA FLOWS ond TUFF ~ =X ", , ot A

Largely Fosz. Pliocene. ¢ " tT Be rreepre L = Fiver

24°00
vor7h

 

 

NN PALALEOZOIC Tne/ T7717 SS 1¢(?)
Sec/inren ls, Lava Flows, TULF

 

 

 

 

 

 

GRAIN TOID INT S/OR,

 

 

 

PRE-TERTIARY

 

H7e/0’

 

 
   
 
 

      
       
  

    
 

Ss RARPEY THE SIS, EL. /chH ES, /9089.
= A aga Ad A \
GON OREGON - IDAHO 3
U.S. GEOLOGICAL SURVEY ‘ ATT NTT NT TT 71. BUTTE QUADRANGLE
WALCOTT DIRECTOR (RR - : R. 47 E1700 '
__R.43 E. EE T.18 S.

Contacts ‘are ently
approx imate ly /ocated.

[f= TERNARY?)

. nd RECENT
PLIOCENE

Lo Von Formation.

 

fFocsws
PRry&T TE
do Formation.

 

FrE- PLiocen.
Easalt, Ahyolii .

TERTIARY

 

/ , \ ; ; NR CEA : YR: : ot Sa T.I9 S.
T.19 S. / (a aA ; Lie \ pe : oho a # MCN eg 4 2 : a pu & : ? : : {

 

 

 
   
 

  
 

T.6 N. Xu
50° -
4
50 :
T.20 S
1
ve
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T2s
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T.22 8.
T.3 N.
T.23 8.
47%
i
8 my Board Cotral. é *
$469N Spr \ (1 (WN
Ne 5 - D\ /
T.24 S. - Jif Sl SOY { = fe s3tind NR 2 ¢ AM ENS Fr gee” oN ENE \ A Strod
’ ) S Z(f [ = \ “TaN
/ \ = [ LS link To
4330" : Le LL / or Rte E R. 45 E. 10° R. 46 E. . ~ 17°00
17°20 R43 EF . 2% RE 2 DIAGRAM OF TOWNSHIR Edition of July 1906.
E.M. Douglas, Geographer. 24 Scale 1286060 6 5 4 3 2 |

W. H. Herron, in charge of section.
Topography by Gilbert You ng.S.T. Penick,
E.R. Bartlett,and Reclamation Service.
Triangulation by C. F. Urquhart.

Surveyed in 19

 

£ hte Eta cinerea M8 re 002 LOUIS WEULE Co. id

I 3
; tbo. 1 7 5 t  rflnees i Chronometers and Nautica

iE [oe = ——— 19:20 21222324 Instraments
g Contour interval 50 feet. 20/28 28.27 26 25 BOOKS ON NAVIGA TION, ETC.

3113233 34 35 36
APEROXIMATE MEAN Datum is mean sea level. Ed ee AGENCY FO

Us 0, GOVEANMENT ONARTS AND PUBLICATIONS
No. 8 GAUFURNIA £1. SAN TRANCISEG

 

 

TRUE NORTH

SURVEYED IN COOPERATION WITH THE STATE OF OREGON.

 

   
A WR 4

 

ERS)
LL

  

   

   
   

 

 
  
 

 

4 Ja _ L er Ld
‘ BM, i:
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THE S/S, EL. /cHES, /909.

8
R. 46 E R. 47 E
BM
4 R—— T.8s
~ Zz) : Contacts are ons

\ approximate ly /ocated.

 

= [Jewragsn
1 : nd RECENT
3 I PLIOCENE

IDAHO Formation.

NL 3

 

 

 

 

 

ELocEws
FRYE TE

© rmotion.

E- Pliocen.
Easalt, rhbyols i

TERTIARY

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 
 
  

 

 

 

 

 

    

 

   

 

 

 

  

      
   

 

 

 

 

 

     
   

 

 

 

 

 

 

 
 

 

 

  

 

 

 

 

 

  

 

 

 

 

 

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T.20 S.
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If t < »
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i . = Alkaly Spr No .
| ~ =
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Ie East Sprin i i
i NE ¢ {NY “
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| i { Oo
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3 x
BM creek
T.23 S. 1
f ki 1
WY Ww
Dry Creek Ww
f Butte
¥
Wy { Zz
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< i 3
7 BM BM, \ y
am / > x KS X \
Ff ~ i y
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S [= n d o mans) . i { 1 A
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8 ,
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"3301 i ! FN AY Ys loads a ar Ar
43 0O'l— i donb - I. Lente — Mss desman] mT . . ,
ve BY 20’ R. 43 E ENGRAVED JUNE 1906 BY U.S. GS. = 20 R.44 E 10 R.48 E. 17°00
A 5 ( J > 1 DIAGRAM OF TOWNSHIR ition of July 1906.
as, Lbeographer (204 ; Scale 125000 ry 5 4 3 2 |
n charge of section 1 /E 1 Pp 5 Mil p.
= i / o 1 2 3 a 5 Miles | 9 10 11 12 Q .
phy by Gilbert Young, S.T. Penick « /& era TEsms—TI— Em T ES 7.8 { LOUIS WEULE CO
# and Reclamation S . HA \ - 1817 16 15 14 13] .
eft,and R eclam: n Service. Jo 3 1 2 3 5 5 Kilometers t { hro .
5 tion by C.F Urquhart 3 /& ] wo. A po Se = [io 20 212223 24) 0 nometers and Nautica Instraments
Surveyed in 1905 kf - - | 5 |
; F Contour interval 50 feet. [30 29 28 27 26 25]
SURVEYED IN COOPERATION WITH THE STATE OF OREGON APPROXIMATE MEAN

   

DECLINATION 1905.

0

Datum is mean sea level.

{ ¥

T

|
[31 32 33 34 35 36]

6 "7 "a To] "10" 11 1/2 1/3 1/q 15

1

8

BOOKS ON NAVIUA MON, ETC.
AGENCY FOR
Us 0 GOVERNMENT OHARTS AND PUBLICATIONS
No. § CAUFORNIA £0, SAN TEANCISTE
 

RIPTION

ites Geological Survey is making

map of the United States. This

s been in
three-tenths of t
essions

e area of the country,
, has been mapped.

outlyi ng P¢ 0S!

J JA
ped areas widely

are
shown on the progress map
annual report of the Director.

bein g represer nite Ar
accompany ix 1g €ac

This great map is b bene published in atlas sheets |
of convenient size, which are bounded by parallels |
and meridians.
land corresponding to an atlas sheet is called a
quadrangle. The sheets are of approximately the

same size: the paper dimensions are 20 by 16% |
inches; the map occupies about 17% inches of |

height and 11% to 16 inches of width, the latter
varying with latitude.
employed. The largest scale is 1:62500, or very

nearly one mile to one inch; i. e., one linear mile |
on the ground is represented by one linear inch on |
This scale is used for the thickly settled |

the map.
or industrially important parts of the country.
For the greater part of the country an intermediate
scale of 1:125000, or about two miles to one inch,
is employed. A third and still smaller scale of
1:250000, or about four miles to one inch, has’
been used in the desert regions of the far West.
A few special maps on larger scales are made of
limited areas in mining districts. The sheets on
the largest scale cover 15’ of latitude by 15’ of
longitude; those on the intermediate scale, 30' of
latitude by 30’ of longitude; and those on the
smallest scale, 1° of latitude by 1° of longitude.

The features shown on this map may, for con-
venience, be classed in three groups: (1) water,
including seas, lakes, ponds, rivers and other
streams, canals, swamps, ete.; (2) relief, including
mountains, hills, valleys, cliffs, etc; (3) culture,
i. e., works of man, such as towns, cities, roads,
railroads, boundaries, etc. The conventional signs
used for these features are grouped below. Varia-
tions appear in some maps of earlier dates,

All water features are shown in blue, the smaller
streams and canals in full blue lines, and the larger
streams, lakes, and the sea by blue water-lining.
Certain streams, however, which flow during only
a part of the year, their beds being dry at other

 

excluding |
The map- |
scattered, nearly every State |

The four-cornered division of |

Three scales, however, are |

TOPOGRAPHIC MAP OF

Ponds which are dry during a

lines. Salt-water marshes are shown by horizontal

water marshes and swamps by blue
| broken horizontal lines.

Relief is shown by contour lines
| Each contour passes through points which have
| the same altitude. One who follows a contour on
the ground will go neither uphill nor downhill,
' but on a level. By the use of contours not only
| are the shapes of the plains, hills, and mountains
shown, but also the elevations.

in,

| of elevation being mean sea level.
line at, say, 20 feet above sea level is the line that
would be the seacoast if the sea were to rise or the
land to sink 20 feet. Such a line runs back up
the valleys and forward around the points of hills
and spurs. On a gentle slope this contour line is
far from the present coast line, while on a steep
slope it is near it. Thus a succession of these con-
tour lines far apart on the map indicates a gentle
slope; if close together, a steep slope; and if the
contours run together in one line, as if each were
vertically under the one above it, they indicate 4
cliff. In many parts of the country are depressions
or hollows with no outlets. The contours of course
surround these, just as they surround hills. Those
small hollows known as sinks are usually indicated
by hachures, or short dashes, on the inside of the
curve. The contour interval, or the vertical dis-
tance in feet between one contour and the next, is
stated at the bottom of each map. This interval
varies according to the character of the area
mapped; in a flat country it may be as small as 10
feet; in a mountainous region it may be 200 feet.
Certain contours, usually every fifth one, are
accompanied by figures stating elevation above sea
level. The heights of many definite points, such
as road corners, railroad crossings, railroad stations,
summits, water surfaces, triangulation stations, and
bench marks, are also given. The figures in each
case are placed close to the point to which they
apply, and express the elevation to the nearest foot

 

only. The exact elevations of bench marks and

 

CONVENTIONAL SIGNS

CULTURE
(printed in black)

THE

part of the year are shown by oblique parallel |

ruling interspersed with tufts of blue, and fresh- |
tufts with |

brown. |

The line of the |
seacoast itself is a contour line, the datum or zero |
The contour

UNITED STATES

. a . | . rv INTRO a) ’ . .

| times, are shown, not by full lines, but by lines of | their descriptioris, as well as the descriptions and
{ dots and dashes.
progress since 1882, and about |

| geodetic coordinates of triangulation stations, are
published in the annual reports and bulletins. of
| the Survey. The publications pertaining to speci-
fied localities may be had on applica tion.

The works of man are shown in black, in which
{ color all lettering also is printed. Boundaries,
such as State, county, city, land-grant, reservation,
| etc., are shown by broken lines of different kinds
| and weights. Cities are indicated by black blocks,
| representing the built-up portions, and country
houses by small black squares. Roads are shown
by fine double lines (full for the better roads, dot-
ted for the inferior ones), trails by single dotted
lines, and railroads by full black lines with cross
lines. Other cultural features are represented by
conventions which are easily understood.

The sheets composing the topographic atlas are
designated by the name of a principal town or of
some prominent natural feature within the district,
and the names of adjoining published sheets are
printed on the margins. The sheets are sold at
five cents each when fewer than 100 copies are pur-
chased, but when they are ordered in lots of 100
or more copies, whether of the same sheet or of
different sheets, the price is three cents each.

The topographic map is the base on which the
facts of geology and the mineral resources of a
quadrangle are represented. The topographic and
geologic maps of a quadrangle are finally bound
together, accompanied by a description of the dis-
trict, to form a folio of the Geologic Atlas of the
United States. = The folios are sold at twenty-five
cents each, except such as are unusually compre-
hensive, which are priced accordingly.

Applications for the separate topographic maps
or for folios of the Geologic Atlas should be
accompanied by the cash or by post-office money
order (not postage stamps), and should be addressed
10 —

THE DIRECTOR,
United States Geological Survey,

Washington, D. C.

 

July, 1905.

 

 

 

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ena peel Pot
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Roads and
buildings

Private or
secondary road

 

Railroads
and stations

Electric railroad

 

 

|
bor
b ail

 

 

 

 

 

Locks  U.S.township and

section lines

 

— —T]

County line

Land-g&rant
IE

City, villag
ough

Triangulation
station

e, or
e

U.Slocating

CO line monument

 

 

 

Boundary

monument

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

ne -..  Xoe
Cane] ry} 0 i ps r =
{CEN} 1 3 —_ 2 x ® > | 1 A cides * | = uss
] ies Church or ne do La

Cemeteries Coke ovens Oil wells Prospect Shaft el Mine tunmel a Light -ship Light 1ik- saving

Mine tunn house .
(showing direction N direction unknown, or beacon station

Bench mark b
schoolhouse

RELIEF

(printed in brown)

WATER
(printed in blue)
—

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

' Levees Intermittent
streams and

ditches

8

 

 

 

 

 

 

 

 

 

Sand and

Salt rt Fresh marsh 2 es
sand dunes

mars

(when shown, printed in green)

 

 

 

 

 

 
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