DEPARTMENT OF THE INTERIOR

JOHN BARTON PAYNE, Secretary

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, Director

Bulletin 721

GEOLOGY AND PETROLEUM RESOURCES OF

NORTHWESTERN KERN COUNTY

CALIFORNIA

BY

WALTER A. ENGLISH

WASHINGTON

GOVERNMENT PRINTING OFFICE 

1921
ADDITIONAL COPIES

OF THIS PUBLICATION MAY BE PROCURED FROM

THE SUPERINTENDENT OF DOCUMENTS

GOVERNMENT PRINTING OFFICE

WASHINGTON, D. C.

AT

10 CENTS PER COPY 

V
CONTENTS.

Page.

Introduction____________________________________ 5

Scope of report_____________________________-___ 5

Field work _____________________________________ 5

Previous publications_____________________________ 7

Geology ___ __.. __ _ _ 8

Stratigraphy ___________________________________ 8

Franciscan formation and associated igneous rocks (Jurassic?) 8

Cretaceous rocks_____________________________ 9

Tejon formation (Eocene)________________i__________ 10

Oligocene (?) rocks___________________________ 12

Vaqueros sandstone and Maricopa shale (Miocene)________ 13

General character.. __ _ __________!__ 13

Correlation and age_-__________________ 15

Local details____________________________ 18

McKittrick to Temblor Ranch oil field__________ 18

West side of Temblor Valley________________ 18

Gould Hill to Agua Media Creek______________ 19

Carneros Creek to Devilwater Creek___________ 21

Devilwater Creek to Bitterwater Valley__________ 21 

Bitterwater Valley northward to head of Antelope

Valley____________________________ 23

North side of Antelope Valley________________ 25

Sandstone dikes_____ ._. ___________________ 25

Relation to petroleum____.._________________ 26

McKittrick formation (upper Miocene, Pliocene, and Pleistocene?) 26

Quaternary sand and gravel _ __ _________ ___ 29

Structure_________^________________ _____ 30

General features _____________________________ 30

Structure of Diablo and Temblor ranges______________ 31

Structure of the area included in San Joaquin Valley__ __ 32

Known anticlines within the valley area_____________ 32

Petroleum resources_____________________ ________ 35

Developed fields________________________________ 35

Historical sketch_____________________________ 35

Geology __ _________ ________________ 37

Devils Den field___________________________ 37

Lost Hills field__________________________ 37

North Belridge field________________________ 37

Belridge field____________________________ 38

Temblor Ranch field_______________________ 38

Prospective areas______________________________ 38

Area occupied by exposed Tertiary formations___________ 38

Area included in San Joaquin Valley ______ _ _____ 39

General features_____ __ __ _ __ 39

Area between Lost Hills and Temblor Range____________ 43

Possible continuation of McDonald anticline___________ 44

Gould Hill to the McKittrick Front________________ 45

Region east of the Lost Hills anticline__________'._ 45

Index _____ _______________.._ 47

3
ILLUSTRATIONS.

Page.

PLATE I. Geologic map and sections of northwestern Kern County, Calif 8 

II. Correlation chart showing variation of Vaqueros and Maricopa

formations along strike_ ___________________ 12

FIGURE 1. Index map of southwestern California showing area considered

in this report___________________________ 6 

2. Diagram showing the production of the Lost Hills, Belridge, 

Manel Minor (North Belridge), and North McKittrick Front 

fields, 1910-1919__________________________ 35 

4
GEOLOGY AND PETROLEUM RESOURCES OF NORTHWESTERN KERN COUNTY, CALIFORNIA.

By WALTER A. ENGLISH.

INTRODUCTION.

SCOPE OF REPORT.

The area treated in this report comprises about 200 square miles 

of hilly and mountainous country and about 350 square miles of the 

alluvium-covered San Joaquin Valley, in which the Lost Hills, North 

Belridge or Manel Minor, and Belridge oil fields are situated and in 

which there appear to be possibilities that other fields may be developed (see fig. 1). The discussion is practically confined to the areal 

geology and to the possibilities of finding oil in untested areas. Conditions in the developed fields are considered solely as a problem in 

structural geology, and no attempt is made to present a study of 

the details of underground conditions. This lack of treatment of 

the developed fields in detail is due both to the circumstances connected with the preparation of the report and to the writer's belief 

that the United States Geological Survey's field of greatest usefulness lies rather in the type of work here set forth than in the study 

of underground conditions of interest to engineers engaged in the 

work of development and production. The California State Mining 

Bureau is now making such studies in much more detail and keeping data obtained more nearly up to date than the Geological Survey, 

under existing conditions, would find possible. The reader is therefore referred for such data to the bureau mentioned.

FIELD WORK.

The field work on which this report is based was done by the 

writer, assisted by W. S. W. Kew, in the fall of 1916. Approximately 

two months was spent in the field. The writer originally planned to 

make this a joint report by himself and R. W. Pack, who was to 

contribute the discussion of the developed fields. However, owing to 

the pressure of other work, Mr. Pack's part will probably be much 

delayed, and it seems best to publish the results available at the

present time.

5
6 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

The same field methods were followed as in previous work in 

California. Copies of the Geological Survey's topographic maps 

enlarged to a scale of 1^ inches to the mile were used as a base for 

recording field observations, and locations for plotting geologic

Area mapped and discussed in this report

Areas on which reports have 

already been published

Other oil-producing districts of the State.

INDEX TO PUBLISHED REPORTS ON OIL

1 San Joaquin Valley north of Coalinga (Bull.603)

2 Priest Valley (Buli:58i;

3 Coalinga (Bull. 398)

4 5alinasValley-Parkfield(8ull.69l)

5 Northwestern Kern'Co.(8ulls. 731 and 406)

6 McKittrick-Sunset(Bull.406)

7 Sunset-Midway (P.Rll6andBull.47i;

8 CuyamaValley(Bull.62lj

9 Santa Maria (Bull.323)

10 5ummerland( Bull.321)

11 Santa Clara River valley(Bull.309J

12 Simi Valley(Bull.69l)

13 Los Andeles (Bull.309)

14 Puente Hills(Bull.309)

15 Barstow-Kramer (Bull 541)

FIGURE 1. Index map of southwestern California showing area considered in this report.

data were determined by the intersection of compass sights to 

prominent peaks or other features which it seemed probable had 

been accurately located by the topographers. Where details of topography seemed to be inaccurately shown, the areal geology as 

mapped (PI. I) was adjusted to fit the topographic details only if
INTRODUCTION. 7

no very material change was required. The geologic lines are therefore not in all places shown in their proper relation to the details of 

topography. No attempt was made to locate any section corners. 

The accuracy of the geologic lines with respect to section corners 

therefore depends on the accuracy with which these corners were 

located by the topographic engineers. Though the land net as shown 

is in all probability substantially correct, where an accurate tie 

between the geology and the land lines is desired the relations of the

two should be checked. ,

 

PREVIOUS PUBLICATIONS.

The following list includes the papers dealing with the geology 

and petroleum resources of the general region considered in this bulletin that have appeared in recent years:

1894. Watts, W. L., The gas^ and petroleum yielding formations of the central 

valley of California': California State Min. Bur. Bull. 3, 100 pp., maps, 

plates, and figures. Sacramento.

Notes on the topography, geology, and oil resources of the Sunset 

district are given on pp. 22-37, and on the McKittrick district (called 

the Buena Vista district in Watts's report) on pp. 41-53; some analyses 

of water from the region are given on pp. 90 and 91.

1900. Watts, W. L., Oil and gas yielding formations of California: California 

State Min. Bur. Bull. 19, 236 pp., maps, plates, and figures. Sacramento. 

Additional notes to those contained in his former report are given 

as follows: Geologic sketch of San Joaquin Valley, pp. 106-109; Sunset 

district, pp. 117-125; McKittrick district, pp. 125-131; Devils Den district, pp. 131 and 132.

1904. Pruteinan, P. W., Production and uses of petroleum in California: California State Min. Bur. Bull. 32, 230 pp., maps, plates, figures, and 

tables. Sacramento.

Maps of the districts and analyses and notes concerning the physical 

and chemical properties of the oils, their uses, methods of refining, and 

other useful data are given in this bulletin.

1905. Anderson, F. M., A stratigraphic study in the Mount Diablo Range of 

California: California Acad. Sci. Proc., 3d ser., vol. 2, pp. 156-548, pis. 

13 to 35, 1 map. San Francisco.

This paper includes a brief discussion of the geology and paleontology 

of the region along the southwestern side of San Joaquin Valley, including the region from Devils Den to Sunset, together with descriptions and illustrations of many of the fossils found in the Tertiary 

formations.

1908. Anderson, F. M., A further stratigraphic study in the Mount Diablo Range 

of California: California Acad. Sci. Proc., 4th ser., vol. 3, pp. 1-40, San 

Francisco.

In this paper Mr. Anderson gives a summary of his earlier paper and 

makes some corrections regarding the age of certain of the formations 

necessitated by a further study of the region.
8 GEOLOGY AND PETROLEUM OF KEEN COUNTY, CALIF.

1910. Arnold, Ralph, and Auderson, Robert, Geology and oil resources of the 

Coalinga district, Fresno and Kings counties, Calif.: U. S. Geol. Survey 

Bull. 398, 354 pp., maps, plates, figures, and tables.

This report includes a discussion of the geology and oil resources of 

the region immediately adjacent on the north to that covered by the 

present report. Many of the discussions apply to the McKittrick-Sunset region.

1910. Arnold, Ralph, and Johnson, H. R., Preliminary report on the McKittrickSunset" oil region, Kern and San L.nis Obispo counties, Calif.: U. S. 

Geol. Survey Bull. 406.

 ,,Describes the geology of northwestern Kern County and gives results of drilling up to date of publication.

1914. McLaughlin, R. P., and Waring, C. A., Petroleum industry of California: 

California Min. Bur. Bull. 69.

Gives good description of Lost Hills and Belridge fields and map 

showing location of wells.

1917. Gester, G. C., Geology of a portion of the McKittrick district: California 

Acad. Sci. Proc., 4th ser., vol. 7, No. 9, pp. 207-227, pis. 33-34.

Points out the unconformable relations of the Maricopa shale and the 

Etchegoin and Paso Robles ("Tulare") formations, and the bearing 

of the relations between the Etchegoin and the Paso Robles on the 

occurrence of oil pools.

1917. McLaughlin, R. P., First Annual Report of the State Oil and Gas Supervisor : California State Min. Bur. Bull. 73.

Chapter 2 gives a description of conditions of water infiltration in 

the Belridge and Lost Hills fields as well as statistics of wells drilled, 

etc.

1918. McLaughlin, R. P., Second Annual Report State Oil and Gas Supervisor:

California State Min. Bur. Bull. 82. 

Gives statistics of wells drilled and a few notes on the progress of

study of underground conditions. 

1918. McLaughlin, R. P., Third Annual Report State Oil and Gas Supervisor:

California State Min. Bur. Bull. 84.

GEOLOGY.

STRATIGRAPHY.

FRANCISCAN FORMATION AND ASSOCIATED IGNEOUS ROCKS (JURASSIC?).

The Franciscan formation, next to the oldest formation that outcrops in the Coast Range, consists of gray and greenish arkosic sandstone, dark and black fissile shale, and thin-bedded chert.1 This 

formation has been generally assigned to the Jurassic on the basis 

of a few fossils found in it and its position beneath the Cretaceous. 

Basic igneous rocks have been intruded into the sedimentary beds in 

nearly all places where they are exposed. According to Fairbanks,2 

most of the intrusive rocks are of pre-Cretaceous age, but an in1 A detailed study of the lithology and probable conditions of deposition of tbe Franciscan formation has recently been published by E. F. Davis, as California Univ. Dept. 

Geology Pub., vol. 11, Nos. 1 and 3, 1918.

2 Fairbanks, H. W., U. S. Geol. Survey Geol. Atlas, San Luis folio (No. 101), 1904.
CD 

ro

 a 

o

2- o'

in 

m 

O

6

r

z 

m

O 

o

Pleistocene (?), Pliocene, Eocene Oligocene (?) Miocene and upper Miocene

JURASSIC!?) CRETACEOUS TERTIARY QUATERNARY
GEOLOGY. 9

trusive peridotite (usually altered to serpentine) is younger than the 

lower part of the Cretaceous. Local contact metamorphism has 

changed the Franciscan sedimentary rocks into schists that have considerable petrographic interest but that occupy very small areas. 

Because of the extremely intricate structure and the small size and 

irregular shape of many of the intrusive masses no attempt is made 

in this bulletin to differentiate the lithologic types in the Franciscan 

or to map the Franciscan separate'from the associated rocks.

Within the area mapped (PL I) the outcrops of Franciscan rocks 

occupy small areas and are confined to the much-faulted district 

around the head of Antelope Valley. The fault-bounded strip of 

Franciscan rocks that extends southward from a locality west of the 

Antelope pump station consists mostly of peridotite and serpentine 

but also contains small areas of schist. In the northeastern part of 

sec. 8, T. 26 S., K. 17 E., is a rocky knob of what appears to be a 

metadiorite, with a marked schistose structure. A small area of 

limestone west of the Antelope pump station is described by Arnold 

and Johnson.3 In sec. 16 there is an area consisting entirely of serpentine and farther south, close to the faulted anticlinal axis in the 

Vaqueros, there are several small areas of Franciscan which Arnold 

and Johnson describe in detail.

No oil is known to occur in Franciscan rocks, and their character 

and structure make it seem unlikely that oil will be found in them 

anywhere. Areas within which these rocks outcrop may therefore 

be safely considered as having no oil possibilities whatever.

CRETACEOUS ROCKS.

The Cretaceous rocks, which consist of dark marine clay shale with 

lenticular conglomerate and sandstone beds of considerable thickness, were deposited uriconformably upon the Franciscan formation. 

Where the Cretaceous rocks are well exposed in the Coast Kanges, 

enormous stratigraphic thicknesses have been measured. West of 

Coalinga a thickness of 19,000 feet of mostly Lower Cretaceous beds 

is present 4 and north of Coalinga a thickness of 24,000 feet of Upper 

Cretaceous rocks. 5 The Cretaceous succession is in some areas broken 

by an unconformity which separates the Lower Cretaceous (Shasta 

series) from the overlying Upper Cretaceous (Chico formation). 

Elsewhere, as within the area here described, no unconformity has

s Arnold, Ralph, and Johnson, H. R., Preliminary report on the McKittrick-Sunset oil 

 region, Kern and San Luis Obispo counties, Calif.: U. S. Geol. Survey Bull. 406, p. 33, 

1910.

4 Pack, R. W., and English, W. A., Geology and oil prospects of Waltham, Priest,

Bitterwater, and. Peachtree valleys, Calif.; U. S. Geol. Survey Bull. 581, p. 127, 1915.

B Anderson, Robert, and Pack, R. W., Geology and oil resources of the west border of

the San Joaquin Valley north of Coalinga, Calif.: U. S. Geol. Survey Bull. 603, p. 37,

1915.

15944° 21 2
10 GEOLOGY AND PETROLEUM OF KERN COtTNTY, CALIF.

'been observed, and the separation, if made at all, must be made on 

the basis of fossils.

The field work for the present report was confined almost entirely 

to the areas that contain outcrops of Tertiary rocks that bear some 

relation to a study of the oil resources of the region. The Cretaceous 

was therefore only mapped where structural complications bring it 

to the surface within the areas of Tertiary formations that border 

the San Joaquin Valley. Outcrops of Cretaceous rocks were examined in a number of areas north of Bitterwater Creek and near the 

Temblor ranch. Most of Barril Valley is underlain by Cretaceous 

shale, good exposures of which are seen along the McGovern Gap 

road. Here, as at other places where the formation was examined, 

it consists of dark-green clay shale that contains intercalated beds of 

flaggy sandstone, most of them one-half to two inches thick, which 

make up perhaps 5 per cent of the stratigraphic thickness. The 

sandstone breaks up into plates, which weather to a dark reddish 

brown. These platy fragments, scattered over a surface covered 

by a clay soil, form reliable evidence of the presence of Cretaceous 

rocks. The soft clay shale is rather easily eroded, and Barril Valley 

is largely an erosional feature, determined by the presence of Cretaceous shale. Another area of lithologically similar Cretaceous 

rocks determines the low topography which extends southeastward 

from Raven Pass to Bitterwater Valley. The Cretaceous area on the 

north slope of Shale Hills contains some prominent beds of hard 

sandstone which weather to a reddish brown. These sandstone beds 

are 6 inches to 2 feet thick, and each bed is sharply separated from 

the interbedded shale, which even here makes up 80 per cent of the 

total thickness.

So far as known, the Cretaceous rocks within this area do not contain oil, except in very small quantities, and no seeps or other evidence of oil have been discovered. The presence of Cretaceous rocks 

at the surface should therefore discourage prospecting, and if penetrated in a well it should be abandoned, as it must have already 

passed all probable oil-bearing horizons.

TEJON FORMATION (EOCENE).

The Tejon formation, which unconformably overlies the Cretaceous rocks, is well represented in the central and southern part o£ 

the area mapped (PL I), where it consists of massive buff sandstone 

and less prominent dark clay shale. North of Bitterwater Creek, it 

is absent, having been entirely eroded previous to the deposition 

of the Miocene rocks, which rest directly on the Cretaceous rocks. 

The massive cavernous-weathering quartzose sandstone is characteristic of the Tejon throughout the southern part of the State, and the
GEOLOGY. 11

formation was recognized within this area largely from its lithologic 

character and stratigraphic position.

The Tejon was examined along the McDonald anticline and in the 

.higher hills from Agua Media Creek southward to the Temblor 

ranch. In the McDonald anticline the Eocene consists of interbedded dark-green shale and light-buff sandstone. Near the top of 

the section there is a massive yellow sandstone that contains a great 

many nearly round concretions from 2 to 3 feet in diameter. These 

concretions are very hard, and as the formation is eroded large 

numbers of them are left lying on the surface of the ground. The 

old sheep corral at the McDonald ranch is built of these concretions. 

A good example of the unconformity between the Tejon and the 

overlying Miocene beds may be seen along the northern end of the 

Tejon inlier in the McDonald anticline.

Farther back from the edge of the valley the Tejon is exposed in 

a continuous outcrop from a locality near Napoleon Spring southward to the Temblor ranch. The characteristic lithology makes this 

formation easily separable from the adjacent formations, and in 

many places clearly marked unconformities both at the base and top 

may be seen.

A paced section of the Tejon, measured along the ridge on the 

north side of Agua Media Creek, shows it to be approximately 1,800 

feet thick, made up as follows:

Section of Tejon formation on north aide of Agiuv Media Creek.

Top of section. Feet.

Alternate sandstone and shaly sandstone and some shale; 

the sandstone beds weather to rather prominent craggy 

outcrops _______ ______ ___________ 400

Hard massive cavernous-weathering buff sandstone; contains irregular nodular concretions_____________ 100

Alternate sandstone and clay shale, comprising five zones of 

shale and four of sandstone; the shale is dark green to gray 

but not as dark as the Cretaceous shale__________ 4001

Concretionary zone, comprising mostly sandstone, together 

with some shale; contains hard round concretions 1 foot 

to 2 feet in diameter______________________ 250

Soft fine yellow shaly sandstone__________ ____ 100 

. Fine-grained yellow sandstone, shaly sandstone, and shale; 

the sandstone forms prominent outcrops on both sides of 

Agua Media Canyon______________________ 800

Soft fine-grained sandstone; weathers to a yellow and red 

soil ________________________________ 275

Base of section. 

1, 825

South of Agua Media Creek the beds shown in the above section 

are present, and in addition about 1,000 feet of overlying buff sandstone, making a total thickness of 2,800 feet. The Tejon thins
12 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

northward from Agua Media Creek. About a mile northeast of 

Walnut Springs it is only 1,000 feet thick, and a short distance 

northwest of Napoleon Spring it is entirely overlapped by the beds 

of the lower Miocene. Farther north, near the mouth of Cedar 

Canyon, the Tejon again appears as a massive sandstone, which is 

exposed for a distance of 2 miles along the strike and reaches a 

thickness of 400 feet.

The Tejon is well developed between Agua Media Creek and Temblor ranch and is composed of material similar to those in the section measured north of Agua Media Creek. Because of the unconformity at the base of the lower Miocene these beds rest on different 

beds of the Tejon in different places, including massive cavernousweathering sandstone, nodular sandstone, and shaly beds.

The only fossils found in the Tejon south of Antelope Valley were 

the following forms from Salt Creek, which, however, are not characteristic :

Fossils from Tejon formation near Salt Creek.

Dentalium sp.? Shark teeth. 

Bryozoa. Brachiopod.

The age determination rests on the lithologic similarity to the 

Tejon beds on the north side of Antelope Valley from Point of 

Eocks northward, where a good Tejon fauna is found near the base 

of the formation.

The Tejon is excellently exposed in the vicinity of Point of Eocks, 

on the north side of Antelope Valley. The writer made only a 

hasty examination of this area, a detailed description of which may 

be found elsewhere.6 The beds consist of nodular, massive, and 

cavernous-weathering sandstone, similar to that which outcrops in

the vicinity of Agua Media Creek. An excellent Tejon fauna was 

collected from hard calcareous sandstone beds near the base of the 

formation.

Like the other pre-Miocene formations within this area, the beds 

of Tejon age in all probability contain no oil. There are no seeps or 

other evidence of oil on the outcrop, and the absence of any diatomaceous shale in it or in older formations within this area makes 

the Tejon an unpromising formation in which to look for oil.

OLIGOCENE ( ? ) ROCKS.

Eocks of possible Oligocene age crop out in the outer hills on the 

north side of Antelope Valley. The writer made only a very hasty 

examination of the region north of Point of Eocks and has fol0 Arnold, Ralph, and Johnson, H. R., Preliminary report on the McKittrick-Sunset oil 

region, Kern and San Luis Obispo counties, Calif.; U. S. Geol. Survey Bull. 406, pp. 38-39, 

1010,
U. 8. GEOLOGICAL SURVEY BULLETIN 721 PLATE II

300 

-' '

30'lSf: 65' . :-. .

50J =

 140';.;.;.-: 

150":';.';^

375 

601

 White and pink 

 hard platy shale

=*=* Reef sandstone 

1 

 Brown shale with

.-.: . Nodular brown sandstone 

 Shale 

 .'-.' Massive light-gray 

' .'-.' . sandstone; fossils

.' . :.: Massive light-gray - 

sandstone ^^**

=; brown clastic shale, 

 with thin yellow

Brown sandstone ^fossils

1

175 

6(X

450

4<X 

40C

300

65'

100'

so!

45 

175

300' 

5'

fin'

130'

 I TT- 

 -^=s~-

 ^=^J t.

L>-"--- -

rl . 1 1 

1 1 1

' ' ' 

s ,,*"

r

s

1 

1 

\

Blocky pink and 

white shale

Blocky pink shale, 

fairly hard,with 

layers of hard, 

platy shale. Yellow calcareous 

lentils common

Same as the underlying, but more 

uniform in characterand hardness

Bluish-white to purplish-brown blocky 

shale, with yellow 

calca reouslentils

Bluish-white and 

pink soft blocky 

shale

Pink shale, with 

few calcareous layers,6 inches to 

Z feet thick

Hard platy shale

Soft purple clastic 

shale, harder toward top

Fine brown sandstoneCup One white shaly sandsto Brown sandstone Slate 

Brown hard sandstone 

Shale 

White sandstone 

Soft purple shale

Hard white sandstone 

main reel" bed

Purple clastic shale 

Hard sandstone

5offbro;vn sandstone 

and sandy shale .few 

sandstone reefs

 * * c*> oo

'»*! Oi o i|r-iA^ O K

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PROBABLE STRATIGRAPHIC LINE_ JX

/

/ i

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150 Platy shale / 

I0' ===== Limestone / 

 ^_ 140' Platy shale /

80' = Blu sh-gray shale _.

50 

375'

20 'S

185 

5 

200'

&*£&

Hard ca carcous re 

sandstone

Hard calca reous s 

stone with congl 

.erate and shaly s 

stone

Soft purple shale vv 

some sandstone 

Hard brown nodular 

stone 

Soft fine shaly sar 

stone 

Hard calcareous si 

stone

Purple clastic sh

Soft and hard sands! 

Hard purple shale

ef"

and 

omand

andith

sarf 

idnd3ls 

cne

450

300 

500

'0, 

100

3CO'

8d 

ICO'

175'

100'

100 

50'

 ^ u^

 '-~- - 

^ «-t^3> : 

1--L- Z^L-

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=T^«=C3»

_ . : -._ ^'

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O 0.

HI

i! II!!

l:| III ml mil

II

§f| 

|||

T?

Nearly white soft 

and nard shale

Purple coarse to" 

clay shale, with 

yellow calcareous 

lentils

Hard platy shale

Brown and purple 

clastic shale, with 

yellow calcareous 

layers

Reef "sandstone

Soft shaly sandstone 

Hard sandstone 

Hard gray calcareous 

sandstone

Soft clastic sha e 

and shaly sandstone 

poor outcrops

Sandy shale 

Hard "Veef sandstone

Prominent hard sandstone reefs wilh interbedded soft sandstone

Soft earthy shale and 

fine sandstone 

Soft br-own sandstone

Herd crown ss.. fossils

s'

-----

450 

500' -

300' -^- 

300 

300 

ZOO'"'-

,000 

zoo' 

125^

200 ;.-- -:_ 

50 -.:.-.

cxip

 Shale 

 Like underly ng but

 : V 

 ; \

 Pinkto white blocky \ 

 diatomaceous shale \ 

 - \

 \

= = \

 Soft sandy shale and 

 sandstone

 P nk clay and dia- 

 - tomaceous shale

 - \

 Hard platy shale y

 \ 

 * 

__ y

 Sandy shale and \ \ 

=.-. f"ne sandstone \ \ 

^ \ v 

 - \

 - \ 

 \

- - \ 

=- \

 Brtwn and purple i 

i^^j clay shale.some

 and interbedded 

 -- sandstone

 Brown clastic shale

 ' Soft sandstone and 

 .- clay shale

>.':' . Fine soft yellow 

- - shaly sandstone

.-. .-. . Thin-beddtd ss,fossils

"I.

S

o 

o_

\

3 ^»~ -*1 

o. < < ra

ft 5,3^? 

o S w_S.

§, i

li 1

I i. ]-

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S ~**r5- en n ^ n 3 °

55 ~I t2-S n> G 'oS'

° ^ ;r<i x °

i = White blocky dia350 ; tomaceous shale

250' . Hard white shale

ROri p,-r,U hlorky ^^(e

r -. . . .-. .-. : Soft shalv sand60u_..._^ stone and sandy 

 .-.;. .-.-. . . shale

::.; .. Pink and purple 

 clastic and dia550 .-. . .-. . . . . tomaceous shale 

 - and shaly sandstone

\

' f^-P-t-^ Hard white cherty \ 

350 5halp

" \

- \

 Brown sandy clay 

- - shale, with calca950'r^^^5; reouslentils 1 to 

......... 2 feet thick

2501 " ' ' - '--V Yet lo^ sandstone,

VERTICAL SCALE 

500 0 500

_-- : Pink to white 

500 blocky shale

\ \

\ -

170 P

, : : : S

350 - - - -: «

125 F

150 : :: :. :': S<

ftiite cherty and 

>locky shale

nk and purple 

hale

oft fine sand-. 

done and shaly 

sandstone

jrpie shale and 

laty pink shale

3ft brown -sanditone

N

1,000 FEET

600 

350

875 

675'

150 

725

 ff 7*.!^

=f 5fT3

Pink blocky shale, 

partly diatomaceous

Hard pink calcareous shale, with 

reefs of finecal-. 

careous sandstone

Brown and purple 

clastic sha/e

Brown' coarse and 

fine sandstone, 

some shale'

Hard cherty shale

fine brown' sandstone and sandy 

purple shale

Basal sandstone 

locally present

SECTION I SECTIpN Z 

Chico Martinez Creek

SECTION 3

South of Cameras Spring

SECTION 4

South side Agua Media Creek

SECTION 5

Composite section measured

on both flanks of syncline west

of McDonald ranch'

SECTION 6 

East flank of anticline 

near McDonald ranch

SECTION 7 . 

Southeast of Raven Pass

SECTION 8 

East side Barril Valley

CORRELATION CHART SHOWING VARIATION OF VAQUEROS AND MARICOPA FORMATIONS ALONG STRIKE.
GEOLOGY. 13

lowed the mapping of Arnold and Johnson, though with some modifications.. According to their description,7 the Oligocene (?) consists of about 1,800 feet of prevailingly pink and brownish weathering 

clay shale, at the base of which lies about 100 feet of nonnodular 

light-gray to buff sandstone inclosing a fossiliferous calcareous reef. 

The fossils found by them are not diagnostic of any particular 

horizon, and the tentative correlation of the beds with the Oligocene 

was based on their position below the reef zone of the Vaqueros. 

The writer believes that more detailed paleontologic and stratigraphic work may show that the Vaqueros, on the north side of 

Antelope Valley, which is mapped by Arnold and Johnson as only 

15 to 150 feet thick, is really the equivalent of the top reef bed of 

the sections south of Devilwater Creek, and that the Oligocene (?) 

is the equivalent of the underlying part of the undifferentiated 

Vaqueros and Maricopa deposits, as shown in Plate II.

Arnold and Johnson describe an oil spring in sec. 23, T. 25 S., 

E. 15 E., in the Vaqueros-reef zone, and several shallow wells get a 

small amount of oil from the underlying shale, a short distance away. 

Farther north, in the Coalinga district, large amounts of oil are 

believed to have originated in Oligocene (?) beds, probably, in part 

at least, equivalent to these.

VAQUEROS SANDSTONE AND MARTCOPA SHALE (MIOCENE). 

GENERAL CHARACTER.

An apparently continuous series of marine sandstone and diatomaceous shale, containing lower Miocene fossils near the base, forms 

most of the foothills along the edge of the valley. This succession, 

which Arnold and Johnson in their report classified as undifferentiated Miocene, Vaqueros sandstone, Monterey shaje, and Santa 

Margarita (?) formation is here treated as a single stratigraphic 

unit. It reaches a maximum thickness of more than 9,000 feet at 

Chico Martinez Creek, where a well-exposed section was measured 

(see PI. II, sec. 2), and consists of interbedded sandstone and shale 

in the lower 1,500 feet, overlain by clay shale and diatomaceous 

shale. Much of the upper part of the shale is nearly white, of light 

specific gravity, and is made up in considerable part of the skeletons 

of diatoms and other skeletal fragments of minute organisms. According to the generally accepted theory, the oil found in this region 

originated in the diatomaceous shale and was formed from the soft 

parts of small organisms, the skeletons of some of which are present 

in the shale. The shale was not only the original source of the oil, 

but sandy beds in the shale formation form reservoirs from which 

many of the wells in the productive fields draw their supply of oil.

7 Arnold, Ralph, and Johnson, II. It., op. -cit., pp. 40^41.
14 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

These formations, therefore, bear a close relation to the oil, and they 

will be described in considerable detail.

Although the Vaqueros sandstone and the Maricopa shale are well 

exposed along the entire length of the foothills which border San 

Joaquin Valley, a nearly complete section is present only between 

Gould Hill and the mouth of Carneros Canyon. Even here the McKittrick formation rests in marked unconformity on the Maricopa 

shale, and a considerable thickness of the shale is undoubtedly overlapped and hidden from view by the McKittrick. The thickness of 

over 9,000 feet now exposed therefore represents a minimum original 

thickness, and the succession as originally deposited was probably 

much more than 10,000 feet thick. North and south of this locality 

the valley alluvium overlaps all the upper part of the series, and the 

study was necessarily confined to the lower beds.

The remarkable variation in lithology of these lower beds is graphically shown in the sections in Plate II. From Devilwater Creek 

southeastward a number of lenticular sandy beds are interbedded with 

the lower 1,200 feet of shale and sandy shale. Some of the zones of 

sandstones weather out prominently into reefs which may be seen 

for miles. The principal reef zones have been mapped as sandstone 

on Plate I. A closer examination shows that even these reef zones 

contain considerable amounts of interbedded shale and that the intervening shale zones contain less prominent thin sandy beds. The 

separation into sandstone and shale can not therefore be shown clearly 

on the geologic map. Above this reef-bed zone lies from 1,200 to 

2,500 feet of pink to brown clay shale and diatomaceous shale, in the 

lower part of which is a prominent zone of hard platy shale and 

chert. These beds are overlain by light-colored to white shale, mostly 

diatomaceous,, over 4,500 feet thick. The base of this upper shale

zone is shown on the geologic map. The line of separation between 

this white shale and the underlying less diatomaceous shale is not 

sharp, and where, because of discontinuous outcrop, the line is not 

actually traceable the horizon shown as the base of the white shale 

may be wrongly placed, because of lithologic variation in the beds 

along the strike. In other words, the line shown as the base of the 

white shale for the area between Temblor Valley and Carneros Spring 

may not be at the same horizon as the lines shown near the mouth of 

Agua Media Creek and in Shale Hills. A comparison of the thickness of the measured sections suggests that the line drawn at the base 

of the white shale for the area south of Carneros Creek indicates a 

considerably higher horizon than the base of the white shale on Agua 

Media Creek. Such a correlation would place the base of the upper 

shale zone about 1,000 feet lower down in the Chico Martinez Creek 

section, and on the map the line would be at the western base of the
GEOLOGY. 15

prominent ridge in sec. 3 and 'of the 1,894-foot hill in sec. 10, 

instead of along their northeastern flank as shown.

The basal reef-bed zone is even more variable north of Devilwater 

Creek than south of it. From Devilwater Creek northward to Bitterwater Valley only a single zone of reef beds near the base of the 

section is present, and it ranges from 100 to 500 feet in thickness. 

North of Bitterwater Valley the lower sandstone is from 500 to 

750 feet thick except in the McDonald anticline. In that fold there 

is an apparent thickness of nearly 2,000 feet in which sandstone beds 

are prominent. The structure along this part of the anticline is irregular and the mapping may not be entirely correct, so the apparent 

thickness may be due to duplication of beds by faults or folds or by 

the crushing and thickening incident to folding. If, as the writer 

believes, the thickness given represents the original thickness it is 

probably due to the sandy beds extending higher in the succession 

here, but there may be an extreme local thickening of the basal sandy 

zone, possibly due in part to overlap.

Farther north, on the northwest side of Barril Valley, a thickness 

of more than 3,000 feet of the lower sandstone was measured, and in 

this locality it appears that the sandstone beds are equivalent to all 

the beds below the horizon of the white shale as mapped in the hills 

east of Barril Valley and farther south.

CORRELATION AND AGE.

The classification of the beds of Vaqueros and later Miocene age has 

caused more disagreement among geologists than that of almost any 

other formations in the Coast Range. The reason for the disagreement lies in the fact that the succession of beds differs greatly within 

short distances and also in the difficulty in correlation by paleontology 

between the nonadjacent areas in which detailed work has been done. 

(See PL II.)

The beds here described as undifferentiated Vaqueros sandstone 

and Maricopa shale are believed to be equivalent in age to at least 

part of the Vaqueros sandstone, Salinas ("Monterey") shale, and 

Santa Margarita formation; but no unconformities or other basis for 

a division into these formations are present. Arnold and Johnson, 

who mapped in detail the area here discussed, divided this succession 

into four units undifferentiated Miocene, Vaqueros sandstone, 

Monterey shale, and Santa Margarita (?) formation. No unconformities are described in their report as occurring between these 

formations, the separation being based on lithologic character or 

faunal content. The reasons for not following the classification of 

Arnold and Johnson may be summarized for each of their units as 

follows:
16 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

The fauna present in the undifferentiated Miocene beds, though it 

contains some species which are found in the so-called Oligocene beds 

of the Mount Diablo region, does not differ materially from the fauna 

in the overlying sandy beds mapped as > Vaqueros by Arnold and 

Johnson. The overlap of the undifferentiated Miocene by Vaqueros 

indicated by Arnold and Johnson's mapping was not borne out by the 

present work. These basal beds and the overlying Vaqueros are lithologically similar and appear to have been deposited during a continuous cycle of deposition. Thus there appears to be no valid f aunal, 

stratigraphic, or structural evidence for the separation of this lower 

unit within the area considered in this bulletin.

Arnold and Johnson's description of the Vaqueros sandstone does 

not state its structural relation to the overlying and underlying 

beds. Apparently no unconformity was found, and it was separated 

from the overlying " Monterey shale " because of its lithologic character. They say:

Despite this [complex structure] the Vaqueros in its more intimate characteristics, as of palaeontology, lithology, color, thickness, etc., is quite uniform. It 

consists nearly everywhere of beds of tawny to brownish medium-grained sandstones, generally containing many fossils, and nearly everywhere calcareous. 

The beds are almost always resistant, and hence produce a characteristic reef 

topography, which alone is usually sufficient to distinguish the beds from any 

others in the region.8

This description, if warranted, would be a valid basis for separation. It is, however, not borne out by the writer's work or by Arnold 

and Johnson's detailed description of the Vaqueros or by their mapping. On their map the Vaqueros unit is used to show reef-like sandstone beds, irrespective of their stratigraphic position. Thus between 

Napoleon Spring and Temblor ranch there are two Vaqueros reefs, 

between which is " Monterey shale." Farther south, in the Midway 

district, a number of other Vaqueros reefs are shown in the " Monterey shale," and some even in the " Santa Margarita (?) shale." Their 

mapping therefore confirms the writer's conclusion that the lower or 

Vaqueros sandy zone grades upward into the " Monterey shale " and 

that there is no definite or even approximate boundary between the 

two which may be traced for any considerable distance. No unconformity has been found and no fossils have been found in the overlying shaly beds, so that it seems preferable to map the reef beds 

simply as sandstone phases in the undifferentiated Vaqueros and 

Maricopa.

The separation between the beds mapped as " Monterey shale " and 

"Santa Margarita (?) formation" is stated by Arnold and Johnson, 

to be based mainly on the lithologic characters,9 though they say that

"U. S. Geol. Survey Bull. 406, p. 43, 1910. 

0 Idem, pp. 55-56.
GEOLOGY. 17

the " Santa Margarita" beds are locally unconf ormable on the 

"Monterey shale," 10 and their areal mapping of the west side of 

Antelope Valley indicates a marked unconformity between the two. 

The writer has mapped a line at the base of the white shale which 

corresponds in a general way. with the separation described by Arnold and Johnson, though differing materially in its location as 

mapped from the line at the base of their Santa .Margarita (?) formation. No evidence of an unconfprmity at this horizon was found 

within the area studied, and the evidence is not regarded as sufficient 

to prove that this particular line marks, the base of the beds equivalent in age to the Santa Margarita formation of the Salinas Valley 

region.

F. M. Anderson,11 in his description of this region, has used the 

names " Temblor formation " for, the lower sandy phase and " Monterey shale " for the overlying shale. As he did not publish a map, he

was not under the necessity of showing the line of separation betAveen the two formations. He believes that the, " Temblor formation " is of the same age as the Vaqueros, but that the name "Temblor" should take precedence because of.a supposed lack of definiteness in the original description of .the Vaqueros. The name Vaqueros, 

however, has been adopted by the United : States Geological Survey.

J. P. Smith 12 uses the name "Temblor" for the sandy beds at the 

base of the succession here described, but, he believes on paleontologic 

evidence that they are younger than the Vaqueros sandstone as originally described and represent the time equivalent of the lower part 

of the Salinas shale ("Monterey shale") of the coast region, where 

it overlies the typical Vaqueros sandstone.

Thus there is a difference of opinion as to the relative ages of the 

beds here described and the Vaqueros sandstone and Salinas (" Monterey") shale of the coast region. Arnold's classification would place 

the basal beds in San Joaquin Valley (Oligocene (?) and undiflferentiated Miocene) below the type Vaqueros; F. M, Anderson would 

have the sandstone formations in the two regions equivalent in age; 

and J. P. Smith would place the " Temblor formation" above the 

Vaqueros. The writer's view is that the Vaqueros sandstone in the 

two areas is roughly equivalent in age, and that during the submergence which began with the deposition of the Vaqueros and 

culminated with that of the Salinas shale each of many small areas 

was submerged at a slightly different time from the rest, so that the

1° U. S. Geol. Survey Bull. 406, p. 63, 1910.

11 Anderson, F. M., A stratigraphic study In the Mount Diablo Range, of California: 

California Acad. Sci. Proc., 3d ser., Geology, vol. 2, pp. 156-248, 1905 ; a further stratigraphic study in the Mount Diablo Range of California : California Acad. Sci. Proc., 4th 

ser., vol. 3, pp. 1-40, 1908.

M Smith, J. P., Geologic range of Miocene invertebrate fossil^ of Califprnia: California 

Acad. Sci. Proc., vol. 3, pp. 161-182, 1912.

15944° 21 3
18 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

basal beds are not everywhere of the same age. However, the paleontologic work thus far done has not been sufficient to show which 

areas were first submerged.

LOCAL DETAILS.

In the following descriptions the area mapped is divided into 

seven districts, within each of which the character of the undifferentiated Vaqueros and Maricopa rocks is fairly uniform. These districts from south to north include (1) the area from McKittrick to 

the Temblor Ranch oil field, (2) the west side of Temblor Valley,

(3) the area from Gould Hill northwestward to Carneros Creek,

(4) the area from Carneros Creek to Devilwater Creek, (5) the area 

from Devilwater Creek to Bitterwater Valley, (6) the area from 

Bitterwater Valley northward to the head of Antelope Valley, and 

(7) the north side of Antelope Valley.

M'KITTEICK TO TEMBLOR RANCH OIL FIELD.

Within the area between McKittrick and the Temblor oil field the 

structure is extremely complicated, so that at most points the areal 

mapping can not show whether the outcropping beds represent the 

upper or lower part of the shale. All lithologic variations of shale 

occur from soft, powdery, poorly bedded white shale to hard, flinty 

material and chocolate-colored clay shale. In the vicinity of Sheep 

Springs several zones of shale breccia occur 'along fault zones. In 

this locality the harder of the thin beds of shale, one-half to 1 inch 

thick, are broken into angular fragments which are scattered through 

a matrix of softer shale. The formation looks like an angular conglomerate and resembles almost exactly certain phases of the McKittrick formation, for which it was apparently mistaken by Arnold 

and Johnson. On the ridge just south of Sheep Springs lie boulders

of this material that have been hardened by local silicification to 

form a compact chert as hard as any found in the Franciscan formation. In the much faulted shale on the north side of Frazer Valley 

there are similar outcrops of shale breccia.

WEST SIDE OF TEMBLOR VALLEY.

The monocline along the edge of the hills farther north gives place 

to complicated structural features, consisting of small eastwardtrending folds and faults along the west side of Temblor Valley. 

The basal 700 feet of Miocene beds exposed in this area is largely 

composed of sandstone, and these beds are overlain by a similar 

thickness of pink to chocolate-colored clay and impure diatomaceous 

shale. A hard calcareous sandstone, which forms the upper half of 

the sandy beds, weathers to prominent reefs. This reef bed wherever 

it was examined, both to the west of the Temblor ranch and to the 

east, where it swings around a small plunging anticline, is about 300
GEOLOGY. 19

feet thick and consists of dark-brown to nearly white coarse sandstone and calcareous sandstone. The calcareous beds weather most 

prominently. They have a pitted appearance, and here and there a 

concretionary nodule stands out in them. Much of the light-colored 

sandstone is cross-bedded, and an especially good example of crossbedding is shown in the reef on the north side of the small syncline 

in the SE. £ sec. 23, T. 29 S., K. 20 E. Below this reef bed lie 

softer sandstone and shale. Toward the south these lower beds are 

more sandy, and a basal sandstone zone has been mapped. West 

of Temblor ranch they consist of brown to dark-gray sandstone and 

shaly sandstone, in which the bedding planes are not very distinct. 

Northward from the south line of sec. 23 these beds below the prominent reef bed are less sandy and consist largely of dark shale, which 

in some places contains fossiliferous sandy beds from 5 to 20 feet 

thick.

GOULI) HIIX TO AGUA MEDIA CREEK.

Within the area between Gould Hill and Agua Media Creek the 

section of the Vaqueros and Maricopa formations that is exposed is 

by far the most complete section that has been measured anywhere 

within the region. The beds, which dip 45°-70° NE., contain no 

miner folds and are excellently exposed. The following section is 

also shown graphically as No. 2 on Plate II:

Section of Vaqueros and Maricopa formations at CMco Martvnez Creek.

Top of section. . Feet.

Very soft, light, porous, nearly white diatomaceous shale. 650

Soft white diatomaceous shale, containing three or four hard 

oherty layers 1 to 5 feet thick in which some tar is present. 275

Hard nearly white cherty shale, considerably crushed and 

breaking into small angular fragments whose interstices 

contain tar and solid bitumen, makes up half the thickness 

and softer pink shale the other half____________ 100

Medium-indurated pink shale, which breaks into large 

angular and discoidal fragments, not very fissile_____ 400

Brown sandstone_______________'. ______________ 5

Medium-indurated pink shale, rather uniform in character, 

containing yellow calcareous beds 6 inches to 1 foot thick 

at intervals of 20 to 100 feet__________________ 1, 405

Pink shale, weathers white, like the overlying shale but 

contains no calcareous beds__.________________ 650

Pink blocky shale; calcareous beds rare____________ 800

Interbedded soft blocky shale and a harder shale that breaks 

into thin flakes; calcareous lentils 20 to 50 feet apart___ 350

Flaky bluish-white shale and softer pink blocky shale, with 

interbedded calcareous lentils 20 to 40 feet apart. A pit 

at the top of this shale exposes a 3-inch vein of selenite 

in the shale; the prismatic crystals are perpendicular to 

tho sides of the vein, which in turn is parallel to the bedding. Several other veins of selenite in the next 100 feet 

of overlying shale________________________ 775
20 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

Soft pink blocky shale, which together with all overlying 

beds is more or less diatomaceous; it forms the base of Feet, 

the upper shale division ___________________ 175 

Gray clastic shale; weathers yellow to pink and contains interbedded layers of hard white platy shale, which cause 

the beds of this zone to weather to ridges; yellow calcareous 

beds are numerous______________________ 950

Gray clastic shale; weathers to bluish white and purplish 

brown and breaks into small crumbly fragments; no calcareous beds _________________________ 400 

Soft brownish, purple-weathering clastic shale; contains few 

calcareous lentils'________________________ 450

Hard shale zone, comprising hard white platy shale and calcareous shale, interbedded with softer clay shale,_____ 300 

Soft yellow clay soil, probably derived from clastic shale__ 225 

Hard brown and white sandstone (upper reef)________ 20 

Fine white shaly sandstone____________________ 60 

Hard sandstone___________________________ 10 

Shale _________________________________ 65 

Hard brown sandstone______________________ 10 

Brown-weathering clastic shale_________________ 100 

White sandstone, fairly resistant reef_____________ 30 

Soft purple clastic shale______________________ 45 

Hard white resistant sandstone; main reef bed________ 175 

Shaly beds comprising purple clastic and slightly diatomaceous shale and soft shaly sandstone___________ 300 

Hard calcareous fossiliferous reef_______________ 5 

Purple clastic shale __________________ 60 

Soft brown sandstone and sandy shale, containing. a few 

thin beds of hard sandstone__________________ 130

8,920

In the reef-bed zone the lower of the two reefs is by far the most 

prominent bed. It reaches a maximum thickness of 250 to 300 feet 

and consists almost entirely of hard gray calcareous sandstone, in 

which fossil fragments are common. Below this reef are much 

thinner, less prominent reefs, each of which.is traceable for only a 

short distance. The basal beds carry abundant well-preserved fossils, and a large fauna could undoubtedly be obtained from, these 

beds by persistent collecting, especially in the vicinity of Carneros 

Springs and farther north, near Agua Media Creek.

The unconformity between the Miocene and the underlying Tejon 

is very striking in this area. Northwestward from the saddle in the 

north west corner of sec. 15, T. 29 S., II. 20 E., the Tejon is seen to 

be overturned. It dips 70°-90° SW., but the dip changes abruptly 

to northeast at the base of the Miocene. Along the contact the Miocene rests on different phases of the Tejon, at one place massive 

sandstone and at other sandy shale and nodular sandstone.
GEOLOGY. 21

CARNEROS CHEEK TO DEVILWATKR CREEK.

Within the area between Carneros Creek and Devilwater Creek 

there are three main reef zones besides a less, prominent basal sandstone. The sandstone zones range 1 from 50 to 300 feet in thickness, 

but the most prominent part of each reef is thinner, usually not over 

25 to 50' feet in thickness. The reefs form long, narrow, dark ridges 

with broad slopes along the dip from which the overlying softer 

shale has been stripped by erOsion. Their appearance is particularly 

striking near the mouth of Santos Creek, where because of some 

minor folding and faulting they form a veritable maze. The reef 

beds are separated by sandy shale and clay shale, the latter generally 

dark gray- when fresh and weathering to purplish brown or dark 

yellow. Above the reef zone lie beds of dark clay shale, including 

a few hard yellow calcareous lenticular beds, and above this dark 

shale conies the white shale division. Within the clay shale there is 

a zone of hard yellow platy shale, which lies from 100 to 500 feet 

above the upper reef and is 150 to 250 feet, thick. Near Carneros 

Creek this zone is not very prominent and is represented by a 20-foot 

bed of hard calcareous shale, but to the north this shale becomes 

thicker and more resistant, and near Devilwater Creek it outcrops 

even more prominently than the sandstone reef beds themselves.

The separation between the white diatomaceous shale and the underlying clay shale is much more distinct near the mouth of Agua 

Media Creek than in the area southeast of Carneros Creek. The upper shale is nearly white and mostly hard and cherty, breaking into 

small angular blocks, some of which are sufficiently silicified to have 

a resinous luster. The greater silicification of this shale as compared 

to that in the section along Chico Martinez Creek is probably due to 

the greater amount*of folding and crushing to which it has been 

subjected. The upper shale in the small area in sec. 13, T. 28 S., 

R. 19 E., on the northeast side of the syncline is less disturbed and 

also softer and more porous.

DEVILWATER CREEK TO BTTTERWATER VATXEY.

Northward from Devilwater Creek the upper reef beds become 

much less prominent and grade into sandy shale. The hard cherty 

zone which overlies the upper reef becomes much more prominent 

than it is farther south, and a zone of shaly sandstone appears above 

the cherty zone.

This lack of prominent reef beds is particularly noticeable in the 

McDonald anticline, in which only the basal 50 feet of the Miocene 

weathers out prominently. This lower bed is made up of calcareous 

fossiliferous reefs, each only a few feet thick, separated by shaly 

sandstone. Where the Vaqueros swings around the axis of the anti-
22 GEOLOGY AND PETROLEUM OF KEEN COUNTY, CALIF.

cline in sec. 31, T. 27 S., R. 19 E., the basal beds' contain, besides 

many large oysters and other Vaqueros fossils, a number of hard 

round concretions from the underlying Tejon, which are fairly 

honeycombed with holes made by boring mollusks. Above the hard 

sandstone lie about 150 feet of softer yellow sandstone, with some 

interbedded clay shale, and these two sandstones make up the sandstone zone as mapped. From the head of Devilwater Creek northwestward a basal zone 500 to 600 feet thick has been mapped as 

sandstone. A hard sandstone reef from 25 to 100 feet thick, a continuation of the lower reef in the area to the southeast, forms the 

top of this lower sandstone phase. Below the reef lies brownweathering clay shale, with which a few reef beds 5 to 20 feet thick 

are interbedded. The following two sections give an idea of these 

lower beds:

Section in. northeastern part of sec. 84, T. 27 S., R. 18 E.

Feet.

Hard brown calcareous sandstone_ ___________ 20 

Soft brown sandy shale and sandstone, with a few thin reef

sandstone beds _________________________ 400 

Massive white quartzose sandstone, in part calcareous___ 100 

Unconformity. 

Cretaceous shale.

Section on east side of mouth of Cedar Canyon.

Feet.

Hard brown fossiliferous reef, composed of calcareous 

sandstone ____________________________ 10

Soft brown sandy shale________ ___________ 350

Hard brown reef, composed of calcareous sandstone, with 

fossils ______________________________ 20

Soft brown clay shale, containing a few thin beds of sandstone ___________ _ _ _ 350

Brown sandstone __________________________ 20

Unconformity.

Massive yellow Tejon sandstone.

Above the lower sandy zone lies from 1,000 to 1,200 feet of clay 

shale, in which lenticular concretionary beds of yellow calcareous 

shale from 6 inches to 2 feet thick are numerous. These beds are well 

exposed in the southeast flank of the syncline in the Miocene beds. 

Above the clay shale zone comes 300 to 350 feet of hard platy shale, 

which forms a series of prominent knobs, trending northwestward 

from the 2,923-foot hill in sec. 7, T. 28 S., R. 19 E. By means 

of this hard-shale zone on the two sides of the closely appressed 

syncline this fold may be traced for 2 miles south of Bitterwater 

Valley, but farther south the hard shale does not form sufficiently 

prominent outcrops to be traceable along the east flank of the syncline. The resistance of this shale to erosion is due to the presence of beds 1 inch to 3 inches thick composed of light-yellow hard
GEOLOGY. 23

platy porcelane'ous . shale interbedded with an equal amount of 

softer clay shale. Northeast of the McDonald anticline this hard 

shale is somewhat different in character. It becomes in this area 

a more uniform hard white shale, which breaks into small blocky 

fragments whose surfaces have a resinous luster. Above the hard 

shale lies a zone of soft brown sandy shale that contains some 

shaly sandstone. This sandy shale forms a well-defined belt of low 

topography in the hills south of the mouth of Bitterwater Valley, 

and the axis of the syncline for about 2 miles south of Bitterwater 

Valley is formed by these beds. Above the sandy zone lies the 

white shale division, which is well exposed on the northeast flank 

of the McDonald anticline, where much of the material is soft 

and porous, like the upper part of the shale in the section on Chico 

Martinez Creek. The white shale also outcrops in the axis of the 

syncline in the high hills southwest of McDonald ranch.

BITTERWATER VALLEY NORTHWARD TO HEAD OF ANTELOPE VALLEY.

The structure in the area north of Bitterwater Valley is considerably 

more complicated than that farther south, and for this reason it is 

somewhat difficult to determine the stratigraphic relations between 

adjacent beds. There is also a puzzling divergence in character 

between the beds along the northward continuation of the McDonald 

anticline and those to the northeast, in the outer hills. This difference in lithologic character appears to be particularly striking on a 

first examination. The Miocene beds, which rest on the Cretaceous 

on both sides of the valley southeast of Kaven Pass, consist in large 

part of a nearly white blocky diatomaceous shale, in which very 

little sandstone or clay shale is noticeable, except in the basal sandy 

zone, which is probably not more than 500 feet thick. In contrast 

to this succession of beds is that which lies between the McDonald 

anticline and the syncline to the east, where the 1,500 to 2,000 feet 

of beds that are exposed along the axis of the anticline include 

purple clay shale, alternating with hard calcareous reef-forming 

sandstone beds and softer brown shaly sandstone, and above the 

lower reef-bed zone a zone of purple clay shale, containing yellow 

calcareous lentils, at least 1,000 feet thick and considerably thicker 

if the section along the ridge north of Bitterwater Valley on the 

east side of the McDonald anticline is not duplicated by faulting or 

folding. This discrepancy in lithology led Arnold and Johnson to 

believe that there is an upper white shale (Santa Margarita(?) 

formation) which overlaps the lower shale and sandstone (" Monterey " and Vaqueros).

After a careful examination the writer came to the conclusion that 

the basal beds in both areas were deposited at approximately the same 

time, even though they differ much in character. The tendency of
24 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

the beds farther east to be whiter and more diatomaceous is also 

notable on the two flanks of the McDonald anticline south of Bitterwater Valley. The sandy beds, which overlie clay shale as exposed 

near Packwoods, do not differ greatly from the beds near the head of 

Devihvater Creek, where many prominent sandstone reefs are present 

in the lower 1,500 feet. The same succession of sandstone and soft and 

hard shale is present in the shale hills as in the area south of the mouth 

of Bitterwater Valley. The lower 500 feet of beds in the shale hills 

consist chiefly of sandstone, though they do not weather to prominent 

outcrops, and fragments of shale derived from the interbedded hard 

shale give the soil a shaly appearance. Locally the sandstone is 

indurated and forms small buttes of a hard calcareous sandstone. 

Hard sandstone of this type was noted at Shale Point, near the east 

line of the SE. J sec. 1, T. 27 S., R. 18 E.; about 1,500 feet south of the 

northwest corner of sec. 12, T. 27 S., R. 18 E.; and about 1.000 feet

'. i * ' ' '

west of the Twisselman ranch buildings in sec. 14, T. 27 S., R. 18 E. 

In each of these localities' the 'hard sandstone is traceable into soft 

sandstone that weathers less conspicuously, £he local prominence 

being due entirely to an exceptional amount of induration. Above the 

basal zone of sandstone is a medium-indurated white diatomaceous 

and clayey shale, which ranges from 200 to 600 feet in thickness. 

The shale weathers to blocky and hackly prismatic fragments and 

contains interbedded buff calcareous shale lentils. This zone corresponds to the purple claj7 shale zone elsewhere and is overlain by 

hard white diatomaceous shale and sandy shale. Thus the same succession is present in the shale hills as elsewhere, though the beds as 

a whole' are much lighter in color 'and more diatomaceous.

Another example of extreme lithologic variation within a short 

distance is the change in character of the Vaqueros formation and' 

Maricopa shale between the hills east of Barril Valley and the 

syncline which trends northwest across sec. 8, T. 26 S., R. 17 E. The 

character of this change is illustrated by the following section and 

by No. 8 of the graphic sections on Plate II:

Section 'of Vagueros sandstone, 'measured across sec.' 6, T. 22 8., R. '17 E., near

head of Antelope Valley.

Top of section. Feet 

Buff-weathering quartzose sandstone containing reef-like beds

5 to 20 feet thick________________________ 100 

Soft shaly sandstone and sandy'shale; weathers to yellow

loam ____________________ ____________ 1, 400 

Quartzose buff-weathering sandstone, alternating hard and 

soft, the hard beds locally forming extremely rugged reef 

outcrops; contains Turritella ocoyana at base_______ 1,800 

Shale and sandstone, the shale largely derived from Cretaceous material _________________________ 300 

Base of section. 

3,600
, GEOLOGY. 25

The lower 1,575 feet of beds in the area east of Barril Valley corresponds to the lower 2,100 feet of mostly massive quartzose sandstone 

in sec. 6. The next 1,225 feet of prevailingly shaly beds in the 

area east of Barril Valley corresponds to the 1,500 feet of sandstone 

and sandy shale in sec. 6. Thus, in a distance of only a few miles 

a succession of shales that contain a small amount of sandstone 

changes to massive coarse sandstone and shaly sandstone. Above the 

3,600 feet of sandy beds in the syncline lies pink diatomaceous shale, 

which corresponds with the upper white shale division in the hills 

that flank the San Joaquin Valley.

NORTH SIDE OF ANTELOPE VALLEY.

The mapping of the 'north side of Antelope Valley is almost entirely copied from Arnold-and Johnson, though with some modifications. According to their mapping, the post-Tejon formations 

include Oligocene (?),' undifferentiated Miocene, Vaqueros, and 

Santa Margarita (?) formations. These beds ate shown in this 

bulletin (PI. I) as Oligocene (?) and sandstone and shale phages of 

the undifferentiated Vaqueros sandstone and Maricopa shale. The 

undifferentiated Miocene mapped by Arnold and Johnson is included 

with the overlying Vaqueros and Maricopa shale.

According to Arnold and Johnson, the Vaqueros consists of 15 

to 150 feet of calcareous sandstone, much of which is fossiliferous. 

It is overlain by pink and white, more or less diatomaceous shale in 

which there is Very little interbedded sandstone or sandy shale. The 

underlying undifferentiated Miocene is not described by them.

' SANDSTONE DIKES.

Dikes of sandstone were noted in the shale at two places. A sandstone dike 100 feet wide and several hundred feet long trends northeastward across the top of the hill just east of the center of sec. 5, 

T. 27 S., R. 18 E., cutting the shale' nearly at right'angles to the 

bedding. The dike consists of a hard, somewhat conglomeratic sandstone and is irregularly stained along the joint planes. Three small 

parallel dikes traverse'the-west slope of the prominent ridge near the 

south line of sec. 3, T. 29 S., E. 20 E., on'the north side of Chico 

Martinez Creek. The sand that formed the sandstone in the dikes is 

supposed to have been squeezed into its present position along 

faults in the shale while it was still in a plastic condition.

Another peculiar effect of pressure is shown in the area that lies 

northwest across Carneros Creek from 'the prominent hill in the 

NE. i sec. 31, T. 28 S.,'K.'20 E. In this "locality a hard sandstone 

reef, which dips 80° NE., is exposed in-the middle of a- succession of 

clay shale beds which dip only 20°. This hard bed resembles the
26 GEOLOGY AND PETBOLEtJM OF KEEN COUNTY, CALIF.

sandstone dikes in that its sides are not parallel to the bedding in the 

adjacent shaly beds. This sandstone, however, shows bedding and 

was evidently forced up through the shales as a rigid mass during the 

folding of the beds.

RELATION TO PETROLEUM.

The oil found in the fields along the edge of San Joaquin Valley 

south of Coalinga is believed to have had its origin in the diatomaceous shale of the Vaqueros and Maricopa formations, the wells 

getting their supply of petroleum from the overlying sandy beds 

and also from sandstone lenses in the shale. It is therefore necessary to determine whether the shale underlies an area to be prospected and at what depth it would be reached in drilling. Its recognition in well logs as brown or gray shale gives a useful datum for 

the correlation of strata between wells, though because of the unconformity at the base of the overlying beds the sands within the 

shale may not be parallel to its plane of contact with the overlying 

(McKittrick) formation.

MCKITTRICK FORMATION (UPPEE MIOCENE, PLIOCENE, AND 

PLEISTOCENE?).

Overlying the Maricopa shale is a formation of marine and freshwater sand, clay, and gravel to which the name McKittrick formation was applied by Arnold and Johnson. These beds largely represent the time equivalent of the Paso Robles ("Tulare") formation of the Coalinga area but include some marine beds toward the 

base that are probably equivalent to part of the Etchegoin formation. 

These beds of Etchegoin age crop out only in a very small area

and were mapped with the overlying beds of Paso Robles age,

though, as shown by Gester, there is an unconformity between the 

Etchegoin and Paso Robles beds in the region immediately adjacent 

to the southeast.13 The relation of the Etchegoin to the Paso Robles 

is of considerable significance in determining the likelihood of obtaining oil in this region, as most of the oil in the developed fields to the 

south is produced from the: Etchegoin formation. The beds described 

in this bulletin as McKittrick are assumed to be of Paso Robles age 

unless it is specifically stated otherwise.

The almost entire absence of rocks of Jacalitos and Etchegoin 

age from the surface within this region and their comparative 

thinness where they are penetrated in drilling are significant. In 

the Lost Hills and Belridge fields beds carrying marine fossils of 

probable Etchegoin age are penetrated in the wells, but their comparative thinness allows the oil sands, which lie directly above the

13 Gester, G. C., Geology of a portion of the McKittrick district: California Acad. Sci. 

Proc., 4th ser., vol. 7, No. 4, 1917.
GEOLOGY. 27

Maricopa shale, to be reached at a relatively shallow depth. If the 

same stratigraphic thickness of Jacalitos and Etchegoin rocks were 

present in these fields as is found in Kettleman Hills the oil sands 

would lie at an unattainable depth. Before any drilling was done 

the failure to recognize that the stratigraphic succession in these 

fields might be the same as that exposed in Gould Hill, rather than 

like that in Kettleman Hills, led geologists to regard the Lost Hills 

as probably very deep territory. The Etchegoin is likewise thin in 

the North Belridge field and is apparently not developed to anything 

like its maximum thickness anywhere in this region. Its presence 

beneath the outcropping Paso Robles beds adds uncertainty to predictions of drilling depths in untested areas, as its thinness is probably due in part at least to erosion in pre-Paso Robles time, and the 

amount of erosion may have been entirely different at points comparatively close together. The unconformity must also be considered in comparing the structure in the Paso Robles at the surface with 

the structure in the oil sands as determined by a study of well logs.

The separation of the McKittrick formation and the overlying terrace beds is in many places difficult because of the lithologic similarity 

between the two, particularly in areas like the Antelope Hills, where 

outcrops are poor and the character of the soil is about the only evidence 

available. In sec. 29, T. 29 S., R. 21 E., an unconformity is present between some flat-lying gravel and boulder beds which cap several 

hilltops and the underlying McKittrick, and an unconformity is 

probably present in most places between the McKittrick and the 

terrace deposits.

The lithologic character of the McKittrick formation is well shown 

in the hills of the McKittrick Front, on the northeast side of McKittrick Valley, though the numerous small folds make it impossible 

to establish the sequence of beds for any considerable stratigraphic 

thickness. The formation as a whole is soft and contains gray clay 

shale, sandy clay, fine and coarse white, yellow, and brown sandstone, 

and shale pebble conglomerate. Locally a hard white limestone bed 

occurs in the clays, and a few of the thinner sandstones are fairly 

well indurated. Of the lithologic types present- the soft gray sandy 

shale and the fine-grained shaly sandstones are the most abundant 

and form over 80 per cent of the total thickness of beds exposed. At 

a number of places the outcropping sands are richly impregnated with 

oil. The oil is confined to the coarser beds, and two oil sands may be 

separated by a parting of shale in which there is no evidence of oil.

From Fraser Spring northward to Temblor Valley the McKittrick 

is poorly exposed and its separation from the terrace gravels is difficult. A line of springs occurs along its contact with the Maricopa 

shale in sec. 33, T. 29 S., R. 21 E., and this contact, which is not'well 

exposed, may possibly be a fault.
28 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

In Gould Hill and to the northwest the exposures of the McKittrick are fair, especially its basal beds, but the structure is complicated by small folds that make it difficult to.measure more than fragmentary sections. 'The basal McKittrick is well exposed in a small 

gulch that trends northward across the eastern part of the area of 

Maricopa shale in sec. 7, T. 29 S..-K. 21 E. The basal bed is a massive fossiliferous conglomerate that contains shale pebbles in a hard 

white limy matrix. This bed is about 10 feet thick and is overlain 

by 30 to 40 feet of soft white and pink sands and shaly sand. Above 

these beds lie beds of brown and gray clays and sands. Just at the 

edge -of the valley a bed of shale-pebble conglomerate, considerably 

silicified, forms the crest of several small hills. The basal bed in 

this section is probably of Etchegoin age. The McKittrick is also well 

exposed on the west side of the small hill in the SE. f sec. 2, T. 29 >S., 

R. 20 E., just' south of Chico Martinez Creek. The basal 50 feet at 

this place consists of a light-gray' porous gravel bed made -up of 

rounded pebbles a quarter of an inch to 2 inches in diameter, of 

quartzite, slate, and white shale and a very few of granite. This 

gravel bed is overlain by soft white poorly bedded shale in which are 

scattered fragments of yellow calcareous shale. All this reworked 

material has been derived from the Maricopa shale, and this phase 

of the McKittrick presents nearly the same appearance as poor outcrops of the shale. One point of difference is that on a soil-covered 

slope underlain by the Maricopa shale the calcareous fragments tend 

to be most numerous along lines parallel to the beds from which they 

were derived, whereas in the McKittrick they are scattered at random over the surface. The same succession is traceable northward to 

sec. 34, where the hill in the south-central part of the section is 

formed of reworked diatomaceous shale, and the lower beds, which

dip 20°, as recorded on the map, are shale-pebble conglomerate.

The low hills that lie mostly in sec. 27 furnish some of the best 

outcrops of the McKittrick. The dip is 30°-40° NE., and more than 

1,500 feet of beds are exposed. Most of the beds are white clay shale, 

largely made up of reworked material from the Maricopa shale, and 

these beds give the hills a whiter appearance than the surrounding 

areas of terrace material. On the southwest slope of the ridge there 

are several limy sandstone beds, which contain marine (upper Etchegoin?) fossils. Several hundred feet farther east, at the point where 

the dip of 40° is recorded on -the map, there is a conglomerate 5 feet 

thick composed of well-rounded granitic boulders in a matrix of 

pure white quartzose sand. Above this conglomerate lie soft gray 

and white clayey and shaly beds, most of which do not furnish good 

outcrops.

In both Antelope Hills and Lost Hills the McKittrick formation 

reaches the surface, but over most of the area it is difficult to deter-
GEOLOGY. 29

mine whether the brown pebbly soil is derived from the McKittrick 

or from an overlying terrace formation. In the Antelope Hills most 

of the surface soil is probably derived from terrace gravels, but a 

fine powdery white sand, which is exposed in a pit on the Belridge 

property, in sec. 35, apparently belongs to the McKittrick formation. At the Belridge camp, in the southeastern part of sec. 35, 

one of the houses is built on a small mound composed of a brown and 

white speckled sandstone, which belongs either to the McKittrick or 

more probably to the terrace gravels. The white specks in the sand 

are hard bits of diatomaceous shale. Sandstone of the same character caps the terrace deposits which form the low hills in sec. 

21, T. 28 S., R. 29 E., a few miles to the southwest.

Gray shale of the McKittrick is exposed at a number of points in 

the northern part of the Lost Hills, where small cuts have been made. 

Terrace gravels also form the surface over part, of the hills, and at'

most points it is impossible to tell whether the surface soil is derived 

from underlying McKittrick beds or from the terrace formation. 

Locally the surface material has been hardened by a superficial deposit of gypsum, and care must be exercised not to mistake this material for the McKittrick.

QUATERNARY SAND .AND GRAVEL.

At the end of the period of deposition of the McKittrick formation 

and during the later part of that period, there was a general folding 

and uplift of the rocks of this region, and thereafter the history of 

the Coast Ranges is one of erosion -rather than of deposition, so that 

Quaternary deposits are comparatively thin and insignificant within 

the area of the recent mountains. The San Joaquin Valley,- on the 

other hand, is supposed to be a geosyncline and to have been the site 

of deposition of a large quantity of Quaternary gravels. Both the 

Sierra Nevada and the Coast Ranges were uplifted near the beginning 

of Quaternary time, and together they are supposed to have furnished 

the material for a Quaternary formation which has been estimated to 

have a thickness in the center of the valley of several thousand feet, 

some estimates being as high as 10,000 feet. Any such thickness of 

Quaternary deposits would put the oil-bearing beds entirely out of 

reach of the drill. Despite this supposed thickness in the center of the 

valley, the Quaternary gravels are only a few feet thick in the Lost 

Hills, which are topographically rather far out in the valley. These' 

hills, however, might be regarded as a part of the area of uplift 

rather than of the geosyncline, but the writer is not convinced that 

there may not be other areas even farther out in the valley in which 

the thickness of Quaternary gravels is small.

At some time during the Quaternary period a surface that presented less relief than the"present surface was established along the
30 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

valley slope of the Temblor Range. Gravels were deposited to a 

thickness of at least 50 feet on this surface, which now lies about 300 

feet above the valley level. Only a very few patches of gravel that 

occupy isolated hilltops have escaped erosion. Other Quaternary 

deposits, which were laid down when the level of the west side of 

the valley was slightly higher than at present, form the low hills that 

lie mostly in sees. 18, 20, and 21, T. 28 S., R. 20 E. These hills 

are formed of soft brown-weathering sand considerably finer grained 

than the valley fill now being deposited.

STRUCTURE. 

GENERAL FEATURES.

The discussion of the structure of this region may appropriately 

be divided into two parts first, the structure of the Diablo and 

Temblor ranges, in which the Tertiary and older formations outcrop and within which the structure has been worked out in considerable detail, and second, that of the area covered by Quaternary valley 

fill, within which much of the structure of the underlying Tertiary 

beds may only be surmised. Within this area covered by the valley 

fill, if anywhere, future prospecting is likely to disclose the presence 

of new productive oil pools, and the structure of the hills is chiefly 

significant with regard to the oil prospects of the region because it 

furnishes a clue to the conditions beneath the valley floor.

The broad, nearly level surface of the valley alluvium may be 

regarded much as if it were an extensive lake, concealing the underlying Tertiary formations up to a certain, level of elevation, and not 

as a line marking a separation between two different types of structure. Though the valley is generally supposed to be determined by a 

geosyncline and the hills by uplift in post-McKittrick time, the edge 

of the hills does not everywhere coincide with a structural line 

separating two such major structural features. During late Quaternary time the western limit of the valley fill has not marked a 

structural line but has steadily extended farther and farther west, 

its location at any particular geologic time being dependent upon the 

amount of deposition of Quaternary gravels which had taken place. 

Thus, early in the Quaternary period the Tertiary beds were probably exposed far out in the present valley, and in the geologic future 

the Quaternary deposits may extend far up toward the crest of the 

present Coast Ranges, obscuring much of the structure which may 

now be seen. The Tertiary structure, however, remains approximately unaltered, and the location of the western limit of valley 

alluvium depends as much on Quaternary deposition as on Tertiary 

structure.
GEOLOGY. 31 

STRUCTURE OF DIABLO AND TEMBLOR RANGES.

Most of the smaller structural features within the area mapped 

are clearly shown on the geologic map (PL I) and need not be 

described in detail. The following descriptions are therefore confined to the larger structural features and to those smaller features 

that are of particular interest because of their connection with the 

accumulation of oil or for other reasons.

The hilly and mountainous region between San. Joaquin Valley and 

the sea is known as the southern Coast Eanges. Individual ranges, 

more or less distinctly separated from the ranges on either side by 

intervening wide valleys, may be recognized within this region. 

These ranges and valleys had a structural origin, having been uplifted or depressed to their present relative positions at the end of the 

McKittrick epoch. That is to say, the ranges owe their present topographic elevation to the uplift, and if the term used to describe an 

analogous origin of features of drainage may be applied to them. 

<they should be called consequent ranges. Many of the component 

ridges and other features of the present topography are due, however, to differential erosion acting on rocks of differing resistance. 

Though they are due to uplift, it is hardly correct to say that all the 

ranges are anticlinal, for the post-McKittrick uplift that formed 

them was only one of many uplifts that affected the Tertiary beds, 

and in some places the latest uplift has elevated a previously formed 

syncline or a block containing complicated folded and faulted structure and thus formed one of the present ranges. Parts of two of these 

recently uplifted ranges lie within the area mapped. The mountains 

north of Antelope Valley form the southern terminus of the Diablo 

Range, and the hills southwest of Antelope Valley are situated on 

the northeast flank of the Temblor Range.

The lines of geologic structure within these ranges trend northwest 

and are therefore roughly parallel to the ranges. The individual 

folds within each range are not, however, exactly parallel to it but 

trend more nearly west. Some of the individual anticlines have a 

tendency to extend out into San Joaquin Valley, where they determine 

low, more or less completely buried groups of hills similar to the 

ranges to the west but smaller, less intensely folded, and not faulted 

to any extent. Thus the Lost Hills anticline and its northern continuation in Kettleman Hills and the parallel Kettleman Plains syncline form an eastward repetition of the structural features of the 

ranges to the west. The folding, however, is less intense, and the 

formations are younger, indicating a decrease in intensity of both 

folding and uplift toward the east. The smaller original uplift 

toward the east has been a considerable factor in determining the 

edge of the present valley, though, as has been pointed out, it has not
32 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

been the only factor, and the edge of the valley does not everywhere 

follow the lines of this change. As most of the productive oil fields 

have, been developed in the belt of these low folds that parallel the 

Coast Eanges on the east, the chief aim of the present work, is to 

determine their location and character.

STRUCTURE OF THE AREA INCLUDED IN SAN JOAQUIN VALLEY.

The Quaternary, valley fill extends farther, west, relative to the 

structure of the Tertiary, rocks, in the, region around Antelope Valley 

than in the region to the north .or. south. In the Coalinga region, to 

the north, the Kettleman Hills, which are determined by an anticlinal 

fold, rise well above the. level of, the valley. South of .the. Kettleman 

Hills, however, the Quaternary deposits have almost completely 

burjed the continuation of this anticline in Lost Hills, as well .as the 

Antelope Hills anticline and the,eastward continuation of the McDonald ; anticline. In Antelope, Valley the alluvium extends westward well within the area of folded and faulted beds which are 0 

characteristic of the mountainous parts of the Coast Ranges. To .the 

south of this area the low outlying folds in Elk and Buena Vista 

hills give rise to hills of considerable height above the valley level. 

The location of. the outlying folds that may exist is therefore more 

difficult to determine in the area, here studied than in the areas to 

the north and south, which, with, their, better exposures, may be 

studied as a guide to the type of, structure that is present within the 

valley and that may be expected ;to occur, within this area.

KNOWN ANTICLINES WITHIN. THE VALLEY AREA.

Only three main anticlines the L/qst Hills, Antelope Hills, and

Belridge are known to be present, within the valley area of northwestern Kern County, and in all three of these anticlines oil has been 

produced. The drill records are the chief evidence of the existence 

of two of them.

The presence of the Lost Hills anticline is strongly suggested by 

the.topography, and besides it has been proved to exist by the drill 

records. The hills consist of a ridge, that has a maximum height of 

150 feet and is about 8 miles long.from northwest to southeast and 

about a mide wide. The western.slope is very gentle, but the eastern 

slope is steeper < and has been dissected to the depth of a hundred fe>et 

by the headward erosion of a number of large gullies. The Lost 

Hiljs have been.so named because, though, easily seen from the east, 

they appear to be lost to one,.on the west, where the slight eastward 

rise is hardly apparent, to the eye. That the hills, are determined by 

structure is indicated by their straight trend and long and narrow
GEOLOGY. 33

form, as well as by the presence toward their north end of several 

low parallel ridges that can hardly be other than the topographic 

expression of underlying beds that are more resistant to erosion than 

the rest. Outcrops are rather scarce, and in many places the character and attitude of the beds that crop out is difficult of recognition 

because of the presence of superficial deposits of gypsum. Several 

of the outcrops appear to belong to the McKittrick formation, which, 

however, is difficult to distinguish from Quaternary gravels. A few 

dips may be seen in the supposed McKittrick formation in the hills, 

but the measurements of all of them are open to some question. Such 

dips as were seen are less than 10° E., and no dips on the western 

flank of the anticline were found. This evidence of itself might only 

indicate a resistant zone in an eastward-dipping monocline. The 

most convincing surface evidence of the anticlinal character of the 

hills is their trend, which is directly in line with the Kettleman Hills

anticline distant about 5 miles from their northwest extremity.

The logs of wells in the Lost Hills field show a well-marked anticlinal structure, with dips of 15° on the flanks of the fold, in beds 

of the McKittrick formation. This dip contrasts with the lower dips 

of the surface gravels and with the lower slope of the flanks of the 

hills where they have not been affected by recent erosion. Although 

several wells have passed into the underlying Maricopa shale, the 

evidence is not sufficient to determine the structure in the shale, 

though there may be an anticline in the shale that has considerably 

steeper dips than those in the overlying McKittrick formation. The 

Maricopa shale lies beneath the McKittrick at a depth beneath the 

surface of only 1,000 feet or less, as contrasted with the Kettleman 

Hills, in which, according to Arnold, there is a thickness of over 

5,000 feet of the Jacalitos and the Etchegoin formations between the 

Paso Eobles and the Maricopa shale. This shows that there must 

be a pronounced rise in the structure of the Maricopa shale between 

the south end of the Kettleman Hills and the north end of the Lost 

Hills.

The surface evidence for the existence of an anticline in the Antelope Hills is rather less convincing than is that for the Lost Hills. 

The Antelope Hills consist of a rather low rise trending from a 

locality southeast of Shale Point southeastward as far as the North 

Belridge or Manel Minor oil field. The hills rise to a maximum of 

about 50 or 75 feet above the valley and at several points are completely traversed by arroyos that lead eastward from the mouths of 

canyons along the edge of the Diablo Range. The top of the hills is 

rather flat and does not as strongly suggest a low dome as does that of 

the Lost Hills. Northwest of Antelope Hills there is an anticline
34 GEOLOGY AND PETROLEUM OF KEEN COUNTY, CALIF.

that is traceable southeastward as far as Shale Point, and presumably this fold continues southeastward beneath the Antelope 

Hills.

The logs of wells drilled in the North Belridge field have not been 

studied sufficiently by the writer to determine whether they prove 

the existence of an anticline. However, the anticlinal theory of the 

accumulation of oil is so well established as regards the California 

fields that the presence of oil in this area is of itself pretty fair 

evidence of the existence of an anticline. The well logs indicate that 

the structure in the McKittrick formation is low, and that the dips 

are less than 10°. The wells penetrate a considerable distance into 

the Maricopa shale, which is reached at a depth of about 700 feet, 

but its dip and structure are not known.

The Belridge oil field is on an anticline, of which, however, there 

is no surface evidence such as outcropping beds or surface elevation. 

The field was located by drilling near a small oil seepage. The following data on structure in this field, as determined from well logs, 

may be quoted from the State mining bureau: 14

The work done in that Held shows that the shallow oil lies above the brown 

shale in a number of sands which are separated by blue shales. It also shows 

that these sands and shales lie unconformably on the brown shale, and that the 

contact surface is roughly anticlinal in form. This should not be construed 

to mean that we have exact knowledge as to the dip and strike of the individual 

beds of the brown shale, for we have not. The overlying sands and blue shales 

form a broad, flat anticline over this irregular ridge of brown shale, but only 

the upper sands are continuous.

The brown shale spoken of here is the Maricopa shale, and the 

overlying sands belong to the McKittrick formation. The much 

smaller thickness .of the McKittrick formation in this field than that 

shown in a section from the hills in sec. 27, T. 28 S., ft. 20 E., southwestward to the base of the McKittrick, indicates that there is a 

pronounced anticline beneath the oil field. In all probability the dip 

of the Maricopa shale in this field is considerably steeper than the 

dip of the McKittrick. The areal relations suggest that the anticline on which this field is situated is a southeastward continuation 

of the McDonald anticline.

The North McKittrick Front field may also lie on an anticline 

which, like the Belridge anticline, has no surface expression, though 

the well logs available at present do not giv.e sufficient evidence on 

which to base any conclusions as to the structure. In fact, much of 

the trouble caused by water in this field resulted from the lack of 

similarity of the recorded logs of the wells, so that the structural 

conditions could not be determined, and thus any satisfactory solution of the trouble, such as shutting the water off at a uniform

14 McLaughlin, R. P., California State Min. Bur. Second Ann. Kept., p. 239, 1918.
PETROLEUM RESOURCES. 35

stratigraphic position, could not be accomplished. This anticline 

may be a northwestward continuation of the Elk Hills anticline of 

the McKittrick field.

PETROLEUM RESOURCES.

DEVELOPED FIELDS.

HISTORICAL SKETCH.

The first productive field to be developed in this region was the 

Lost Hills field, the first well in which was drilled in 1910. Thereafter the Belridge, Manel Minor (now called the North Belridge),

13" I9IZ

FIGURE 2. Diagram showing the production of the Lost Hills, Belridge, Manel Minor 

(North Belridge), and North McKittrick Front fields, 1910-1919.

and the North McKittrick Front fields were successively developed. 

The number of producing wells and the combined production of the 

first three of these fields are shown on the accompanying chart 

(fig. 2), together with the price of oil. The figures used are those 

of the Standard Oil Co. of California. The graph of the total production shows four separate trends, representing four phases in the 

history of these fields. The first period extends from the middle of 

1911 to the middle of 1913, during which the daily production increased from a few hundred barrels to about 16,000 barrels a day. 

This phase represents the initial rapid development of a new field 

(the Lost Hills) and was accompanied by an increase to a total of
36 GEOLOGY AND PETROLEUM OF KEEN COUNTY, CALIF.

about 125 producing wells. The fall in the average daily production of each well from a maximum of 400 barrels a day during 

the initial stages of the field to 125 barrels a day, though rapid, was 

not sufficient to offset the effect of the rapid increase in the number 

of wells. The second period extends from the middle of 1913 to the 

end of 1915, during which there was a gradual decline in the total 

daily production of the fields to 11,500 barrels a day. During the 

first part of this period the decline resulted from the continued rapid 

falling off of the average production of the wells, which dropped to 

60 barrels a day and which was not offset by the continuation of an 

active drilling campaign. During the later half of this period the 

falling off in average production was very much less, because the 

period of flush production had passed, but the low price of oil caused 

a practical stagnation in drilling, and the result was a decline in total 

production. The third period lasted from the beginning of 1916 till 

September, 1917, during which there was a gradual increase in total 

production, brought about by the high price of oil, which stimulated 

drilling, together with the addition of the Belridge and North Belridge areas as productive fields. The fourth period extends from 

September, 1917, to the present time, during which there has been 

a decline in production despite the stimulation of high prices. In 

this period the field enters upon its old age, during which an inevitable decline takes place, and the possible effect on production of 

high prices is small.

In addition to the fields mentioned, there are two smaller fields 

the Devils Den and Temblor Kanch fields within the area in which 

the Tertiary formations outcrop. These fields have had some production, though it is very small in comparison to that of the other 

fields. The Devils Den field contains four or five wells only a couple 

of hundred feet in depth, which get a barrel or two of oil a day 

from shaly beds below the hard Vaqueros sandstone reef bed. The 

Temblor Kanch field draws its oil from approximately the same 

horizon and is also very shallow territory. However, some of the 

wells in this field are reported to have produced for a short time in 

1911, during the most productive stage of the field, as much as 200 

barrels a day of oil that had a specific gravity of about 15° Baume. 

Water in considerable volume soon made its appearance in the wells 

and the production dropped to a maximum of 10 barrels a day in 

one or two of the best wells. This area was one of the first areas in 

the State prospected for oil. Wells were drilled near the seeps in 

this area during the early sixties, when the oil industry was just 

getting its start in the United States. Even before that time it is 

reported that the old settlers used the tarry oil from the seeps to 

grease their wagons.
PETROLEUM RESOURCES. 37 

GEOLOGY.

Devils Den field. The small amount of oil produced in the Devils 

Den field comes from a few shalloAv wells, less than 200 feet deep, in 

sec. 25, T. 25 S., R. 18 E. The oil comes from a sandy bed in the 

shale, mapped as Oligocene (?) by Arnold and Johnson, which lies 

just below the rather prominent Vaqueros reef bed. Possibly where 

this bed lies at a greater depth it will be more productive.

Lost Hills -field. The productive territory of the Lost Hills field 

is now completely outlined, and sufficient development has been done 

to determine the structure with considerable accuracy. Most of the 

oil comes from the basal beds of the McKittrick formation, directly 

overlying the Maricopa shale, which is supposed to have been the 

original source of the oil. The structure is anticlinal and the dips 

are 10° to 15° on the flanks of the fold in the McKittrick formation.

There is considerable irregularity in the McKittrick, sandy beds, 

shale, and clay being interbedded in lenticular bodies which can not be 

correlated with certainty in different parts of the field. The oil 

comes from several sands which extend through a stratigraphic 

thickness of a couple of hundred feet, stray oil sands being found 

at different horizons within this zone, though two main sands yield 

most of the oil. There is a general plunge of the beds to the south 

and a further increase in depth southeastward, because at the southern end of the field the oil sands lie at a lower horizon than at the 

northern end of the field. Toward the flanks of the anticline the 

sands seem to diverge from the underlying shale, so that a bed a 

certain distance above the shale on the axis of the fold will be farther above the shale on the flanks of the fold. The wells range in 

depth from 300 feet at the north end of the field to 1,600 feet at the 

south end, where the oil is replaced by edge water, which likewise 

limits the field on the flanks of the anticline.

The quality of the oil differs according to the distance above the 

shale, the lightest oil coming from the beds close to the shale, near 

the axis of the anticline, and the heavier oil from upper beds and 

those farther from the axis. In the southern part of the field the oil 

ranges from 30° to 38° Baume, whereas farther north oil from 15° 

to 30° is obtained from the upper sand.

North Belridge field. The oil in the North Belridge field comes 

from two horizons both in the Maricopa shale and about 1,500 feet 

apart. The McKittrick is only about TOO feet thick here, and below 

it is the Maricopa shale. The upper oil zone is reached at a depth of 

about 2,500 feet and the lower at about 4,000 feet. Above the lower 

zone lies a water sand, which has been rather troublesome in some of 

the wells. The well logs available are insufficient to establish the
38 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

anticlinal character of the field. The wells that reach the lower zone 

are the most productive, and their maximum initial capacity is 1,000 

barrels, whereas the capacity of those in the upper zone is only 

about 50 to 100 barrels a day.

Belridge -field. In the Belridge field, as in the North Belridge 

field, the productive sands lie at two horizons a considerable distance 

apart. Most of the oil is derived from sands in the McKittrick 

formation a short distance above the Maricopa shale. These wells 

are from 600 to 1,000 feet deep. The sands are lenticular and correlations between wells are rather difficult, so that the details of structure are imperfectly known. It appears that there is a low anticline in the McKittrick formation. Several water sands are apparently interbedded with the oil sands and thus careful mechanical 

work in drilling the wells is necessary. The lower oil zone, which 

lies in the Maricopa shale, has been reached in a few wells at a 

depth of.about 3,000 feet. The oil, like that produced elsewhere in 

the shale series, is light and the initial production is good, but the 

wells fall off rapidly and water infiltration is troublesome.

Temblor Ranch -field. In the Temblor Ranch field the oil occurs 

on the south flank of a small anticline at about the same horizon as 

in the Devils Den field. This horizon is in the lower 2,000 feet of the 

series, as shown in section 1, Plate I. The limits of the field are 

defined for the known sand, but lower productive sands may be 

present. The oil is viscous and its gravity is about 15° Baume. 

Only the crest of the fold is productive, and the dips are rather steep, 

possibly 25° to 30° along the limits of the field.

0

PROSPECTIVE AREAS. 

AREA OCCUPIED BY EXPOSED TERTIARY FORMATIONS.

New fields may be discovered either in the area in which the 

Tertiary formations of the Diablo Range outcrop or in the area 

covered by the alluvium of the San Joaquin Valley. The chance of 

finding new fields appears to be much better in the San Joaquin 

Valley, even though in the other area the structure is much more 

perfectly known. In fact, because the knowledge of the structure 

of the hills is fairly complete, it may be said, with fair assurance of 

correctness, that there is little chance that fields will be found 

within that area. The chief reason for the lack of favorable areas to 

prospect in the hills is that there are no large areas of Maricopa 

shale properly folded and overlain by sufficient cover to retain any 

oil which may have been formed in it. The only area of seeming 

promise in the hills is the region of Temblor Valley, where the eastward-trending anticlines in the Maricopa shale may contain oil at 

the same horizon as the oil found in the Temblor Ranch field. At
PETROLEUM RESOURCES. 39

best any such fields would probably be of small extent and small yield. 

Another possible area is the southeast side of Temblor Valley, where 

the Maricopa shale is closely folded but where some of the folds 

might be productive like those in the old McKittrick field, where 

steeply folded beds on a sharp, overturned anticline yield the oil.

AREA INCLUDED IN SAN JOAQUIN VALLEY.

General features. The oil pools thus far discovered within the 

area of the San Joaquin Valley are determined by anticlinal structure, and the existence of other pools is probably dependent on the 

existence of anticlines other than those now productive. The problem presented is whether there exist any other anticlines which are 

favorable for testing, and if so to determine if possible their locations. There are no outcrops of Tertiary beds, nor is £here other 

surface evidence to indicate the presence of anticlines other than 

those now productive, though there is some evidence of the extension 

of the known folds beyond the areas which have been thoroughly 

tested. The following discussion therefore relates largely to the 

possibility of finding new productive folds by drilling more or less 

at random within the alluvium-covered area of the valley. The only 

guide to such drilling would be an assumed trend of folds parallel 

to the other folds of the region and a distance between the folds 

similar to that between the folds in the areas where they are exposed 

at the surface or otherwise proved to exist, and an assumed continuation of the known folds beyond the areas where their presence is 

already proved.

The first point to be considered is the likelihood of the existence 

of buried folds. It is therefore pertinent to inquire what are the 

surface features by which the known folds are marked, and what, 

if any of them, may be expected to mark any other folds that may 

exist. The surface evidence of the presence of the known folds, 

which incidentally are all productive of oil, are topographic rise, 

outcrops of Tertiary formations within an otherwise alluviumcovered area, and the presence of oil seeps. In the following paragraphs it will be demonstrated that all anticlines may not be marked 

by hills. Likewise, the outcrops of Tertiary formations are not 

necessarily present, as they only indicate the presence of a former 

range of hills composed of Tertiary rocks which has been completely 

buried as a topographic feature but in which the covering over the 

crest is so shallow that the underlying Tertiary beds outcrop in a 

few isolated places. The presence of oil seeps is also obviously dependent on the thickness of the beds overlying the oil-bearing horizon and their permeability to the upward-migrating oil, so that if 

the cover is thick or especially impervious there would be no seeps, 

even though there was a large amount of oil in the underlying rocks.
40 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

In the writer's view, hills are not necessarily present in areas that 

have anticlinal structure. The correspondence between topographic 

forms and the forms of the Tertiary anticlines is not as close as has 

often been stated. Both the Lost Hills and the Antelope Hills anticlines are marked by hills as topographic features, but on the other 

hand the topographic features in the Belridge and North Belridge 

fields show little or no indication of the folds. The Lost Hills 

and the Antelope Hills are remnants of much more prominent hills 

which were formed during the post-McKittrick period of folding. 

After their uplift they were eroded to low domelike forms and a 

small thickness of gravels was deposited over their crests. More 

recently a slight climatic change has resulted in the cutting of numerous small gullies on the flanks of the otherwise even domes. Except 

for the recent modification in form they represent mature to old-age 

topography of an arid cycle. These hills conform to the Tertiary 

anticlines in location, but their slopes are less steep than the dips in 

the underlying McKittrick formation. Also the location of the hills 

may be somewhat shifted from the area directly over the anticlinal 

axes, because of unequal erosion, as apparently has happened in the 

Lost Hills.

This conception of the origin of the present topographic features 

and of their relation to underlying structure is significant and differs 

markedly from theories previously advanced and widely accepted. 

Thus Arnold and Johnson apparently hold that the even, domelike 

form commonly presented was produced by an uplift, which has 

been followed by no great amount of erosion. They say:

Seen from a distance, Elk Hills, if the very youthful but very numerous 

drainage lines be eliminated, must present much the same appearance that it 

did when formed. 15

Presumably the term " when formed " refers to the post-McKittrick 

period of folding, as there is no mention of any later folding believed 

to have taken place. Also, it is implied, though not explicitly stated, 

that they not only "present much the same appearance as when 

formed," but that they are in fact the original hills, practically unaltered by erosion, which were formed by the uplift mentioned. 

With regard to the Lost Hills they state: 16

While the evidence is not absolutely conclusive, the Lost Hills range, which 

rises about 200 feet above the surrounding plain, is believed to be an anticlinal fold of such recency that its original form, except for the erosional scorings upon the surface, has not been lost.

The writer's view is that the dome of the Elk Hills, like that of the 

Lost Hills, is an old-age feature of erosion in an arid climate, and 

that the hills have been subjected to a very large amount of erosion in

15 U. S. Geol. Survey Bull. 406, p. 76, 1910. 

>8 'Idem, Idem. p. n. 7fi. 76.
PETROLEUM RESOURCES. 41

post-McKittrick time. According to the theory of Arnold and 

Johnson, there would seem to be very little chance that any postMcKittrick folds could °exist without an expression in the topography, and consequently prospecting in areas unmarked by hills 

would have very little likelihood of success. On the other hand, if 

we assume that there has been a great deal of erosion since the hills 

were formed, it may well be that other structural hills have been 

eroded to such an extent that they have been overridden by the rising 

level of Quaternary gravel and are consequently no longer represented by any topographic feature whatever.

That the writer's view of the origin of the hills is correct seems 

to be proved by the lack of correspondence between the geologic 

structure and topographic form of several ranges of hills. The 

most striking illustration of this divergence, perhaps, is Kettleman Hills, in the Coalinga area to the north. Kettleman Hills 

were presumably formed at the same time as Elk Hills and Lost 

Hills. Kettleman Hills are a low domelike range of hills, slightly 

modified by recent erosion, essentially similar in form to Elk Hills. 

However, the geologic structure leaves no possible doubt that there 

has been a great deal of erosion since their uplift, as the Paso 

Robles and upper Miocene formations, if restored over the crest 

of the anticline of the hills, would produce a range of mountains 

6,000 or 7,000 feet high, though the hills are at present only as 

many hundred feet above the surrounding plains. Likewise all 

along the edge of the Temblor Range, between McKittrick and 

Sunset, the McKittrick has been affected by a great deal of erosion 

since the post-McKittrick uplift. It seems hardly likely that there 

would be any such discrepancy in the amount of erosion in postMcKittrick time as would be necessary if the Elk Hills and Lost 

Hills are only very slightly modified in form since their original 

uplift. Though the Elk Hills conform very closely in form to 

the underlying structure, the dips on the flanks of the hills are 

rather greater than the slope of the surface. Such agreement in 

form as there is between topography and structure is probably due 

to the fact that the beds forming the hills are of fairly uniform 

hardness throughout, so that in the course of erosion there would 

be very little tendency for hard beds to form prominent ridges 

and cause the shape of the hills to depart from that developed 

by the original uplift. Also, it happens that the structure of the 

hills would present nearly the same topographic form as that 

which they would tend to take; in the normal course of arid-climate 

erosion. In the Lost Hills, too, the structure of the McKittrick 

formation does not parallel the slope of the surface dome but is 

much steeper, as is proved by the well logs, a line of evidence which 

was not available at the time that Arnold and Johnson wrote.
42 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

If the form of the different ranges of hills is not that developed by the original post-McKittrick uplift, it may still be urged 

that they were formed by a later uplift, possibly in late Quaternary time, since which they have been only slightly modified by 

erosion. This hypothesis, too, seems unlikely to the writer, though 

it is less easily disproved than the one just presented. If such a 

later uplift had occurred, there would probably be some beds that 

were deposited in post-McKittrick time but prior to the supposed 

uplift and that had been tilted by it. Yet no such beds are present. All the Quaternary gravels show only such dips as they 

probably had when they were deposited. Further, the form of the 

Lost Hills is not one that would probably have been developed 

by uplift alone. They form a topographic terrace that has a comparatively steep slope on the east and a very low gravel-covered 

slope on the west. This form is easily accounted for, and would be 

expected if a low dome had been overridden by gravel deposits from 

the west; but a structural terrace of this type would be a rather 

peculiar form for an uplift to take. Likewise, the low parallel 

ridges which occur along the length of the hills could hardly have 

been formed by an uplift unmodified by erosion, though they are 

easily accounted for as the result of the action of erosion on tilted 

beds of unequal hardness.

As shown by the preceding discussion, if other folds were formed 

within the valley area they may have been completely hidden, as far 

as surface evidence goes, at the present time. But is there any reason to believe that any such folds were actually formed? Are there 

any buried folds between those now known, or are there others farther out in the valley than those now known? There is no direct 

evidence bearing on this question. The likelihood of such folds depends on whether the folding which took place was sporadic in character or whether it affected all parts of the area over which it took 

place without leaving any unfolded areas or " holes " in a region in 

which the rocks elsewhere were folded, and on how far eastward in 

the valley the folding extended. It would seem that as the folding 

was a result of stresses which acted over large areas the folding was 

continuous over those areas but with diminishing intensity from the 

center of greatest activity, and that in so far as the beds presented 

fairly uniform resistance in adjacent areas the folds were probably of 

about the same steepness and about the same distances apart but in 

general of decreasing intensity toward the valleys, irrespective of 

whether the folds are exposed to view or are masked by alluvium. 

Thus there may well be one or more anticlinal folds in the wide alluvium-covered area between the Lost Hills and the edge of the Temblor Range to the west.
PETROLEUM RESOURCES. 4

The distance to the east that the folding extended is rather harder 

to approximate. The Lost Hills anticline marks the eastern limit of 

the known folds, and on the east side of the valley, in the region of 

the Kern Elver oil field, where the Tertiary beds are well exposed, 

there is a more or less regular low monoclinal dip toward the west. 

However, on the east side of the valley the Tertiary beds are comparatively thin and rest on a rigid granitic basement, which slopes 

gradually toward the west under the valley.

The presence of this rigid foundation may have prevented the 

folding of the Tertiary rocks as they have been folded along the 

western margin of the valley. The eastern limit of folding very 

likely lies along a line where the granitic rocks reached such a depth 

that they were below the zone of activity of the forces causing the 

folding in this interior area. This line can not be determined from 

the surface, but it is reasonable to postulate that the forces which 

caused the folding did not die out abruptly. The folding in the Lost 

Hills is rather marked, and the absence in that region of so large a 

thickness of upper Miocene beds (representing the Jacalitos formation and the lower part of the Etchegoin formation) indicates that in 

the past, at least, there was considerable folding and uplift in a part 

of the valley far out from the edge of the present Coast Kanges. The 

writer's opinion therefore is that in Tertiary time San Joaquin Valley was not a geosyncline of unfolded Tertiary beds, but that there 

were anticlines and synclines of considerable magnitude farther out 

in the valley than the Lost Hills fold. The possible location of such 

folds as may exist between or beyond the known folds will be 

discussed in the following description of separate areas within the 

region studied.

Area between Lost Hills and Temblor Range, In the alluviumcovered area some 12 miles wide between the Lost Hills and the edge 

of the Temblor Kange one or more folds may be present. Elsewhere 

the anticlines out in the valley beyond the edge of the mountains are 

from 4 to 6 miles apart and are progressively closer together the 

nearer they are to the edge of the mountains.

The folds in this area are probably not farther apart than elsewhere and thus suggest the presence of an anticline about midway 

between the Lost Hills anticline and the North Belridge (Manel 

Minor) anticline.

The presence of an anticline in this area is also suggested by the 

structure of the Tertiary rocks on the two sides of Antelope Valley. 

The pre-Miocene formations outcrop much farther to the east on the 

north side of Antelope Valley than on the south side. The Miocene 

beds which form Wagonwheel Mountain must therefore swing westward around the axis of a plunging anticline or else be faulted down 

on the southwest side. A fault with downthrow on the southwest
44 GEOLOGY AND PETROLEUM OF KERN COUNTY, CALIF.

side has brought Miocene beds into contact with older rocks near the 

head of Antelope Valley. This fault probably continues a considerable distance to the east beyond the area where it is exposed, probably well into T. 26 S., R. 18 E., but still farther east it may give 

way to an anticline, like many of the faults which extend eastward 

into the zone of less intense folding. There is therefore some reason 

to suspect the presence of an anticline trending southeastward from 

a point south of Point of Rocks, possibly passing near the 707-foot 

bench mark in sec. 20, T. 26 S., R. 19 E. Such an anticline should 

be favorable for the accumulation of oil.

The stratigraphy and structure of the rocks beneath Antelope Valley west of a line drawn north and south through Point of Rocks is 

probably similar to that of the hills on either side; and if so, the 

rocks are too much disturbed and the older formations are too extensive for this area to be favorable for prospecting for oil.

Possible continuation of McDonald anticline. The McDonald 

anticline is traceable for a distance of about 15 miles in the hills. 

At its north end the fold has its origin in the much-faulted area west 

of Barril Valley. From the; north line of T. 27 S. it is traceable 

southeastward as a well-marked steep fold. Just north of Bitterwater Valley there is a southward plunge of 15° to 20°, which brings 

the shale over the axis. South of Bitterwater Valley the fold is less 

closely compressed, and the doming brings up the Tejon along the 

axis. Where the fold approaches the valley alluvium toward the 

southeast it plunges 8° to 9° southeastward. Beyond the edge of the 

valley there is no topographic evidence of its continuation. The 

other folds that are known to extend out into San Joaquin Valley 

are marked by low hills, so there is some doubt as to whether this 

fold extends to the southeast or plunges steeply and merges with the 

monocline that flanks the range south of this region as far as Gould 

Hill, as does the Ciervo anticline, north of Coalinga,17 which is well 

marked in the higher hills but plunges to the southeast and merges 

with the monocline along the edge of the valley. It has, however, 

already been pointed out that there is no surface evidence of the 

probably continuous anticline between Lost Hills and Kettleman 

Hills, so the lack of surface evidence does not preclude a continuation of the McDonald anticline. The writer believes that this anticline, which is traceable for a considerable distance within the hills, 

may not terminate at the edge of the valley, but that more likely it 

continues for at least several miles beneath the Quaternary valley 

filling. The position of the Belridge oil field suggests that it lies 

on a continuation of this anticline.

17 Anderson, Robert, and Pack, B. W., Geology and oil resources of the west border of 

the San Joaquin Valley north of Coalinga, Calif.: U. S. Geol. Survey Bull. 603, geologic 

map, 1915.
PETROLEUM RESOURCES. 45

Gould Hill to the McKittrick Front. In Gould Hill there are several small folds in the McKittrick formation that trend N. 60° W., 

and in the north end of the McKittrick Front similar small folds 

that trend N. 75° W. Between the two areas lies the alluvium-covered Temblor Valley, along the west side of which the folds in the 

Vaqueros and Maricopa rocks trend nearly east. The probable extension of these folds must be considered. The folds from the west 

side of the valley may extend eastward between Gould Hill and the 

Temblor Front or, as appears more likely, they may swing around 

toward the southeast parallel to the trend of the folds in the McKittrick formation and possibly connect with the folds in the hills 

northwest of McKittrick. In sec. 8, T. 29 S., R. 20 E., the Maricopa 

shale strikes nearly east, although the contact at the base of the McKittrick trends N. 30° W., and in the small area in which the shale 

crops out in sees. 7 and 18, T. 29 S., R. 21 E., its strike is considerably 

nearer east than that of the surrounding McKittrick formation. It 

therefore seems likely that the east-west folding was produced previous 

to the folding that affected the McKittrick formation, and therefore 

none of the folds in the McKittrick trend east. The small folds in 

Gould Hill probably continue southeastward beneath the alluvium 

and are not affected by the folds mapped on the west side of Temblor 

Valley.

The folds in the hills of the McKittrick Front and on the east 

flank of Gould Hill are small and close together. Apparently as the 

folds approach the edge of the main range they become progressively 

closer together. This close folding probably does not extend far out 

from the hills, and any folds farther out than the north McKittrick 

Front are probably wide apart and regular in structure. The writer 

thinks that possibly the Belridge anticline continues southeastward 

parallel to the McKittrick Front and that this area would be more 

likely to contain a well-developed anticline than the area nearer the 

hills on the west. Another place which seems rather favorable is 

in the locality where the Lost Hills and North Belridge anticlines 

would intersect if projected, for if either of the two folds continues 

with unaltered direction there would be an anticline at that place.

Region east of the Lost Hills anticline. Though there is no surface evidence of the presence of any folds east of the Lost Hills, the 

possible value of any discovery in this area makes it advisable in the 

writer's opinion to test the region far out in the valley by one or more 

deep wells. Even if an initial well failed to obtain any oil, if the 

Quaternary deposits were found to be thin the indications would be 

favorable and would warrant further prospecting. In view of the 

spacing of folds elsewhere the writer suggests that a belt 6 to 8 miles 

east of the Lost Hills anticline would include the area in which another anticline is most likely to be present.

INDEX.

Page.

Agua Media Creek, area extending* 

from, to Gould Hill, 

Miocene formations in_ 19-20 

section of Tejon formation on_ 11 

Anderson, F. M., views' of, on the 

Miocene formations of 

the region ___ 17 

Antelope Hills, McKittrick formation exposed in__ 28-29 

structure of __________ 33-34 

Antelope Valley, area extending 

from, to Bitterwater 

Valley, Miocene formations in_______ 23-25 

north side of, Miocene formations in__________ 25 

rocks In _________.____ 9 

Tejon formation in ____ 12 

Anticlines, additional, probability

of_____________ 42-#3

burled, possibility of______ 39-43

surface evidences of_ 39

descriptions: of__ __ 32-35

shifting of hills over____ 40

Areas, prospective, for oil pools 38-45

Arnold, Ralph, and Johnson, H. R.,

cited __________ 16, 40 

views of, on the Miocene formations of the region 15-17, 

23,25

Belridge field, geology of_______ 38 

Bitterwater Valley, area extending 

from, to Devilwater 

Creek, Miocene formations in,__________ 21-23 

area extending from, to head of 

Antelope Valley, Miocene formations in__ 23-25 

Boulders, chert, occurrence of, near

Sheep Springs _____ 18

Carnoros Canyon, section of Miocene

rocks near 14 

Carneros Creek, area extending 

from, to Devilwater 

Creek, Miocene formations in________ 21 

Cedar Canyon, section at mouth of- 22 

Chlco Martinez Creek, McKittrick

formation exposed near- 28 

section of Vaqueros and Maricopa formations on 19-20 

Coast Ranges, southern, origin of 31 

Cretaceous rocks, nature and distribution of_______ 9-10 

oil absent from _ 10

Pago.

Devils Den field, geology of_____ 37 

production in_______._..._ 36 

Devilwater Creek, area extending 

from, to Bitterwater 

Valley, Miocene formations in_________ 21-2y 

area extending from, to Carneros Creek, Miocene formations in _______ 21 

Diablo Range, structure of_____ 31-32 

Dikes, sandstone, occurrence and

origin of________ 25-20

Elk Hills, extent of erosion on__ 40-41

Etchegoin formation, thinness of_ 20-27

Field work, record of_________ 5-7 

Folds. Sec Anticlines. 

Fossils, occurrence of ___ 12,13, 20, 22 

Franciscan formation, nature and

distribution of_____ 8-9 

oil absent from.________ 9

Geology of the region_________ 8-35 

Gould Hill, area extending from, 

to Agua Media Creek, 

Miocene formations in 19-20 

McKittrickj formation exposed

in_____________ 28 

section of Miocene rocks near_ 14 

Gould Hill and the McKittrick 

Front, possible anticlines between-_____ 45

Hills, extent of erosion on_____ 40-42 

formation of, by late uplift-_ 42 

not all anticlines now surmounted by__________ 39, 40

History of production _______ 35-36

Jacalitos formation, thinness of___ 26 27 

Johnson, H. R., Arnold, Ralph, and,

cited __________ 16, 40 

views of, on the Miocene formations of the region 15-17, 

23, 25

Jurassic (?) rocks, nature and distribution of ______ S-9

Kern County, northwestern, geologic

map and sections of_ 8

Kettleman Hills, extent of erosion

on ___ 41

Kew, W. S. W., work of_______ 5

Lost Hills, anticline marked by 40 

extent of erosion on___ __ 40-42 

McKittrick formation exposed

in______________ 28-29 

possible" anticline east of____ 45

47
48 INDEX.

Page.

Lost Hills and Temblor Range, possible anticline between 43-44 

Lost Hills anticline, structure of__ 32-33 

Lost Hills field, geology of_____ 37 

production in 35-36

McDonald anticline, possible continuation of 44 

Tejon formation in_______ 11

McKittrick, area extending from, 

to Temblor ranch, oil 

field, rocks of_____ 18 

McKittrick formation, age of____ 26 

Maricopa shale hidden by__ 14 

nature and distribution of___ 27-29 

oil content of___________ 27 

McKittrick Front and Gould Hill, 

possible anticlines between _________ 45 

McLaughlin, R. P., cited_______ 34 

Man el Minor field. See North

Belridge field.

Map, geologic, and sections of 

northwestern Kern 

County __________ 8

Mapping, method followed in____ 6-7 

Maricopa shale, correlation and age

of_____________ 15-18 

depth to, in the Lost Hills and

Kettleman Hills____ 33 

in the North Belridge

field____________ 34, 37 

nature of_____ __ 13-15 

oil in__________________ 13, 26 

reef zones in_____ __ _ 14 

reworked material from____ 28 

section of, at Chico Martinez

Creek__1_______ 19-20 

variation of, along strike, correlation chart showing _ 12 

Miocene rocks, correlation and age

of____________ 15-18 

nature of_______________ 13-15 

oil in________________ 13,26 

reef zones in____ _ 14 

white shale in, position of base

Of______________ 14-15

North Belridge field, geology of__ 37-38 

structure of- _ 34 

North McKittrick Front field, structure of_=______ 34-35

Oligocene (?) rocks, nature and distribution of_______ 12-13 

oil content of_ _ 13

Paso Robles formation, time equivalent of__________ 26 

Production, history of________ 35-36 

Prospecting, probable success of_ 38 15 

Publications, previous_ _ _ 7-8

Page. 

Quaternary sand and gravel, source

and deposition of__ 29-30

Reef-bed zones, nature and position

of_____________ 14-15

Reports, earlier 7-8

Salt Creek, fossils from__ ___ 12 

Sandstone, Cretaceous, nature and

distribution of_____ 9-10 

Eocene, nature and distribution

of________.____ 10-12 

San Joaquin Valley, possibility of

additional pools in__ 39-45 

structure of part of area in__ 32 

Santa Margarita formation, evidence

as to differentiation of- 15-17 

Scope of the report___________ 5 

Seeps, prevented by impervious cover- 39 

Shale, Cretaceous, nature and distribution of________ 9-10 

Eocene, nature and distribution

of_____________ 10-12 

Smith, J. P., views of, on the Miocene 

formations of the region 17 

Stratigraphy of the area._______ 8-30 

Structure of the area_________ 30-35 

Subdivisions of the area_ ____ 18

Tejon formation, nature and distribution of________ 10-12

" Temblor formation," use of name, 

by F. S. Anderson and 

J. P. Smith_______ 17

Temblor ranch field, area extending 

to, from McKittrick, 

rocks of- - 18 

geology of 38 

production in 36

Temblor Range, gravels on slope of- 29-30 

structure of___-_ _ 31-32

Temblor Range and Lost Hills, possible anticline between 43 44

Temblor Valley, chances for discovery of oil in____ 38-39 

west side of, Miocene formation

in_____________ 18-19

Tertiary formations, exposed, chances 

for discoveries in area 

Of _____________ 38-39

Vaqueros sandstone, correlation and

age of_____--___- 15-18 

nature of___ _ __-___ 13 15 

oil in__________________ 13,26 

section of, at Chico Martinez

Creek__________ 19-20 

near head of Antelope Valley ____________ 24 

variation of. along strike, correlation chart showing-- 12

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