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= me s JOHN C. MERRIAM

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VOLUME 6. ?
1, The Condor-like Vultures of Rancho La Brea, by Loye Holmes Miller aa eed 156 6
2. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern
Nevada, by John C. Merriam, Part I—Geologic History................ce-cssseceo-seresseneesns

3. The Geology of the Sargent Oil Field, by William F. Jomes -002....t.escsecsccenseuenecereness

4, Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, by
Hoye Holmes Miller...) srsccss--.-.--0-n-s0ncnetetsquseapiehenncnrctteenene: sais sats te aaseeees ne ee!

5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A. Reid”

6. Note on a Gigantic Bear from the Pleistocene of Rancho La Brea, by John |
Merriam.

7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Des <

by John C. Merriam. fa
Nos, 6. and 7 im On@ COVED .-W..u...--neteneseene=sosnncorsnsiapdupueneet cones >eteeeeeng ae aan a yu
8. The Stratigraphic and Faunal Relations of the Martinez Formation to the bona
and Tejon North of Mount Diablo, by Roy E. Dickerson .....-........-ss--cssessensensensees

9. Neocolemanite, a Vuriety of Colemanite, and Howlite from Lang, Los Angeles:
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10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor... ‘

11. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern a,

Nevada, by John C. Merriam. Part Il.—Vertebrate Faunas .....-....-.sc---sseesee-n I
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13. Notes on the Relationships of the Marine Saurian Fauna Described from the 1
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19. The Hlastic-Rebound Theory of Earthquakes, by Harry Fielding Reid ....

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VOLUME 7.
1. The Miner: |s of Tonopah, Nevada, by Arthur S. Eakie
2. Pseudostra Afication i in Santa Barbara County, California, by George Davis ial
back ca
3. Recent Discoveries of Carnivora, in the Pleistocene of Rancho La Brea, by Bi
AMO r PIO 25. s2c5--- iene ooccayaesenig esas bes sist h od bane: Bon eee ano coed cen ot
4. The Neocene Section at Kirker Pass on the North Side of Mount Diablo, by B
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5. Contributions to Avian Palaeontology from the Pacific Coast of North America,
Juoye:Folmes Maller 2.35 cb bucesinc pide lbp ushecmesiensetes ot abeneeetas cb eects a Stelosren ee

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 9, No. 1, pp. 1-8, 5 text-figures Issued June 29, 1915

NEW SPECIES OF THE HIPPARION GROUP
FROM THE PACIFIC COAST AND GREAT
BASIN PROVINCES OF NORTH AMERICA

BY
JOHN C. MERRIAM

CONTENTS

PAGE
Birt aT OLIN lO TM ae eee ane oes cesar cee zc fe Mees Sess, sean 2¥ec Sotelo ice ewcahnaccczate daageseee’ seas entennaeeeesseeeereee? 1
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TELSigay mention oy al Ko a oS) On ee =e PEE 6

INTRODUCTION

In recent studies of Tertiary faunas occurring in the region west
of the Wasatch Range several species of the Hipparion type have
appeared which seem distinct from any thus far described. As this
group has considerable importance in discussion of the West American
Tertiary and reference to the species is necessary in papers in which
specific descriptions seem not properly included, it is deemed desir-
able to present a brief statement of the characters of the new forms

at this time.

NEOHIPPARION GIDLEYI, n. sp.

Type specimen, an upper molar three, no. 21382. Probably from:a stratum
just below the coal seam at a mine on the Lawler Ranch, six miles east of
Petaluma, California. The formation has been doubtfully referred to the San
Pablo Miocene, but may represent a later period.

2 University of California Publications in Geology [ VoL. 9

This species resembles Neohipparion affine in its large size and in
the high degree of lateral compression of the protocone. The anterior
and posterior fossettes (fig. 1) are narrow transversely and the enamel
surrounding them shows comparatively few pleations. Neohipparion
gidieyi seems to be distinguished from N. affine by its narrow fossettes,

Fig. 1. Neohipparion gidleyi, n. sp. M*, no. 213882, type specimen, natural
size. Outer and occlusal views. Lawler Ranch, six miles east of Petaluma,
California.

Fig. 2. Neohipparion molle, n. sp. M*, no. 21370, type specimen, natural size.
Inner view and cross-section near base of distal third. s, point at which cross-
section is cut. Lower Jacalitos, Pliocene, North Coalinga region, California.

wider protocone, and slightly larger size. The two species are evi-
dently closely related and seem to represent nearly the same stage of

evolution.
MEASUREMENTS OF TYPE SPECIMEN
ME. anteroposterior diameter 2222 ccccccecteseee rere ceeseeeeeeeeeeneeerer 26.7 mm.
M®, greatest transverse diameter 22 iczeccceseessese seeeeereereererse 20.6
M*, anteroposterior diameter of protocone ...............------------ 18.7

M®, greatest height of worm ChOWdD) ....222022 0-2 nnsecncnmeecnen carne 59.9

1915] Merriam: New Species of the Hipparion Group 3

NEOHIPPARION MOLLE, n. sp.

Type specimen, an upper molar, no. 21370, from the Jaealitos formation of
the North Coalinga region, California. This species is characterized by length
and narrowness of the upper cheek-teeth, simplicity of the enamel borders of
the narrow fossettes, and unusually long anteroposterior diameter of the laterally
compressed protocone.

Compared with specimens of Hipparion mohavense from the
Ricardo Pliocene, the tooth crown in N. molle is smaller, the fossettes
are relatively narrow, and the walls of the fossettes show less plication.
The protocone of the Jacalitos species is absolutely wider anteropos-
teriorly and much narrower transversely.

The form represented by specimen no. 21370 (fig. 2) resembles
Neohipparion montezumae deseribed by Leidy from Laeaultipan,
Hidalgo, Mexico, in general dimensions. In the type specimen of
N. montezumae the borders of the fossettes are more complheated while
the protocone is not as wide anteroposteriorly and is relatively less
compressed laterally than in the Coalinga form. Better material of
both the Mexican and the Coalinga forms may show closer relationship
or even identity of the two. NV. sinclairii of the Rattlesnake Pliocene
in eastern Oregon is of the same general type as NV. montezumae and
N. molle.

MEASUREMENTS OF TYPE SPECIMEN

M’, anteroposterior diameter .... - a19.3 mm.

IMS TRITANSViCTSCECTAINCL OL s22c:2ce-.cvece to ccce seco sat heeatacee-eeeeeexecierace a15.8
M’, anteroposterior diameter of protocone ~..................----..- 9.4
VIE Seema pi ile Ost CIO Wittens cee eee seee =n seee sess seers reece eseceeeas- esses AO

a, approximate.

NEOHIPPARION LEPTODE, n. sp.

Type specimen, a lower molar, no. 19414, Thousand Creek Beds, Thousand
Creek, Nevada. Crown much elongated, slender, relatively straight, well ce-
mented, much compressed laterally. Metaconid-metastylid column long antero-
posteriorly, narrow transversely, with wide, flat internal groove. Hypoconid ridge
prominent. A strong external protoconid ridge present.

Specimen 19414 (fig. 3) from locality 1101 in the Thousand Creek
region resembles in many respects the peculiar Equus curystylus de-
seribed by Cope? from the Goodnight? Beds of Paloduro Canon, Texas.
Gidley? considers the horizon at which this fauna was found as upper

1 Cope, E. D., Geol. Surv. Texas, 3rd Ann. Rep. for 1891, p. 48, pl. 12, figs.

7-8, pl. 20, fig. 6. Issued 1892.
2 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 19, p. 682, 19038.

4 University of California Publications in Geology [ Vou. 9

Miocene. KF. eurystylus is distinguished by extreme narrowness of
the lower molar crowns, by the great anteroposterior diameter of the
metaconid-metastylid column and its close ap-
pression to the protoconid and hypoconid, and
by the presence of an anteroexternal ridge on
the protoconid and one on the hypoconid. These
characters of EH. eurystylus appear in no. 19414
from Thousand Creek. The lower molar (M,)
from Thousand Creek is very long and narrow

and was heavily cemented. The anteroexternal
ridges on the protoconid and hypoeonid are

ASA ke gy ey AINE

strongly developed, as in EL. eurystylus. As in

i
!

Cope’s species, the external ridge on the hypo-

conid forms a prominent ridge on the middle of

we Ns

the external face of the crown.

Gidley* held that Cope’s Equus eurystylus
represented the genus Hipparion. While it is
true that the anteroexternal ridge of the proto-

conid and most of the other characters of E.
eurystylus may appear in milk teeth of Equus,

Gidley’s reference of this form to a group in or
o, near Hipparion is well supported.

Fig. 3. Neohipparion Specimen no. 19414 from Thousand Creek
leptode, n. sp. Ms, no. ae r
19414, type specimen, represents a species In many respects near Neo-
natural size. Inner and hi Ne ; 2 1

: rpparion eurystyle: ye). The Thousand
occlusal views, Thousand ee aoe ey, tyle? (Cope) : ¢
Creek, Pliocene, Thou- Creek form is larger and the details of structure
sand Creek, Nevada. fae ao
are sufficiently different to separate the two, at
least, tentatively. It also resembles other American forms of the
Hipparion group, as Neohipparion occidentale, in many characters, but
seems not clearly referable to these species. The writer has, there-
fore, referred the Thousand Creek form tentatively to a distinet species.

MEASUREMENTS
N. leptode,
no. 19414 N. eurystyle
M,, greatest anteroposterior diameter ..............-.----------10----- 29-+- mm. 24
Mi. transverse diamet er) zicccsc: gos eeeoccese: ceeds sc ecae ee eee seer eee 11 10
M., greatest lenothiot crown 2 ccccccc oes o eee see eaeeeeeceee 66 55
M., anteroposterior diameter of metaconid-metastylid column 14.6 13

3 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 14, p. 126, 1901.

1915] Merriam: New Species of the Hipparion Group i)

An upper molar* (no. 12581) from the same locality as the lower
molar no. 19414 presumably belongs also in or near the Hipparion
group. This tooth is long and nearly straight. The outer styles are
well developed. The mesostyle is of almost even width throughout its
whole length. The fossettes are unusually narrow transversely and
show a few strong plications. The inner side of the tooth is broken
away and it is not possible to determine the characters of the protocone.

MEASUREMENTS OF No. 12581

M', anteroposterior diameter near base —.....................--2-..----- 21.7 mm.

M', length of slightly worn crown ...............-.......... eee 65.8

HIPPARION PLATYSTYLE, n. sp.
Neohipparion, sp. Merriam, J. C., Univ. Calif. Publ., Bull. Dept. Geol., vol. 7,
p. 375, figs. la to 1c, 1913.

Type specimen no. 19830, a second upper premolar from the Orinda Pliocene
southwest of Mount Diablo, California.

A single tooth obtained from the Orinda beds represents a member
of the Hipparion group not clearly identical with any known form.
The crown is large and well cemented. Though somewhat worn, the
form of the fossettes suggests that the crown was never greatly elon-
gated. The small protocone pillar is distinct and is flattened laterally.
The fossettes are slightly narrower than in Hipparion mohavense.
Their enamel walls are moderately crinkled. The outer styles are
heavy.

This species most nearly approaches the Hipparion forms of the
Ricardo fauna. It differs from H. mohavense in its more strongly
flattened protocone and transversely narrower fossettes. The char-
acters of a single specimen (no. 19478) from the Ricardo fauna ap-
proach those of the Orinda specimen, but are not sufficiently near to
warrant the conclusion that the two are specifically identical.

MEASUREMENTS OF TyPE SPECIMEN

P?, greatest anteroposterior diameter -...................22---0.10-- 25.8 mm.
Baporeatest trans erse iam CUCM ssseecesescecseceses-sneceece eee aes 21.6
P?, anteroposterior diameter of protocone ~................----...... 8.2

4See Merriam, J. C., Fauna of Virgin Valley and Thousand Creek, Univ. Calif.
Publ. Bull. Dept. Geol., vol. 6, p. 268, figs. 32a and 32b, 1911.

6 University of California Publications in Geology [ Von. 9

HIPPARION CONDONTI, n. sp.

In the collections of Professor Thomas Condon, formerly of the
University of Oregon, there are two specimens representing a proto-
hippine horse of Hipparion type obtained from sedimentary deposits
of eastern Washington. The Ellensburg formation, in which these
remains were found, has generally been considered as Miocene on
the basis of its flora and is commonly correlated with the middle
Miocene Masceall formation of the John Day basin in eastern Oregon.
The material obtained by Professor Condon is of unusual interest, as
it represents the only available mammalian remains from the Ellens-

bure beds.

gay iLiijil i Pea oan
F s. }

Ai Sati!
VND allt:

Fig. 4. Mipparion condoni, n. sp. P, and M,, no. 672, Univ. Oreg. Col. Type
specimen, natural size. Outer and occlusal views. Ellensburg, Washington.

Fig. 5. Hipparion condoni? n. sp. Lower incisors, no. 668, Univ. Oreg. Col.
Natural size. Ellensburg, Washington.

Of the two specimens from Ellensburg one (fig. 4) consists of two
lower cheek-teeth (no. 672, Univ. Oregon), the other is the anterior
portion of a lower jaw with five incisors (fig. 5) (no. 668, Univ.
Oregon). Both specimens are partly covered with a matrix consisting
of moderately coarse, gray sandstone. It is to be presumed that both
specimens are from the same locality.

The lower cheek-teeth represent P, and M,. The teeth are hypso-
dont, but appear to be considerably worn. In their present stage of
wear, they are not longer than the crowns of some of the advanced
Merychippus forms from the late Miocene. In an unworn state they

1915] Merriam: New Species of the Hipparion Group 7
may have attained a length considerably greater than that normal in
Merychippus. Both erowns are heavily cemented at the summit. The
metaconid-metastylid column is longer anteroposteriorly than in any
Merychippus form known to the writer and corresponds in this diam-
eter to the dimensions of the column in species of the Hipparion group.
The groove between metaconid and metastylid is wide and flat as in
Hipparion, rather than narrow and sharp as is commonly the ease in
Merychippus. The parastylid extends inward as far as the inner
border of the metaconid. A sharp anteroexternal ridge is developed
on the protoconid. The valleys anterior and posterior to the meta-
conid-metastylid column are comparatively narrow transversely, owing
to the large size of the metaconid and metastyld. These valleys cor-
respond approximately in size to those commonly seen in Hipparion,
and are narrower than those in most species of Merychippus. The
entoconid is large and unusually full on the anterointernal side. In
Merychippus this region of the entoconid is commonly not as wel!
developed and may be truneated obliquely. In Hipparion this region
of the entoconid is commonly full and the anterointernal angle is
nearly a right angle, as in the Ellensburg specimen.

The fragment representing the symphysial region of the lower jaw
with the incisor teeth (no. 668, Univ. Oregon) is from an animal not
differing greatly in dimensions from a number of Merychippus speci-
mens from the Upper Miocene of the Barstow region. The incisors
are considerably worn, but still show the inner enamel rings of the
pits. No satisfactory material representing this portion of the adult
dentition of Merychippus from the Maseall Miocene is available for
a comparison. The teeth are in general larger than those of Mery-
chippus calamarius of the Barstow Miocene and are much smaller than
incisors of a large Hipparion from Rieardo. On the somewhat worn
crowns shown in figure 5 the enamel invaginations are clearly shown
on all three teeth. The incisors were evidently deeply cupped, but
this condition obtains also in the ineisors of Merychippus, although
the infolding of the enamel on the third lower incisor of Merychippus
is much less strongly marked than on the Ellensbure specimen.

The stage of advance shown by the cheek-teeth of the Ellensburg
specimen seems to the writer to be that of Hipparion rather than that
of Merychippus. The form represented in no. 672 does not correspond
exactly to any species known to the writer and may be designated as
a new species, Hipparion condoni. It is distinguished by the size of
the crown and by the size and form of the metaconid-metastyhd

8 University of California Publications in Geology [ Vou. 9

column. Hipparion mohavense of the Ricardo Pliocene seems to be
the nearest form among the species west of the Wasatch. The Ellens-
burg species seems to differ from H. mohavense in flatness of the outer
walls of the protoconid and hypoconid and in the greater prominence
of the anteroexternal angle of the protoconid. Both of these char-
acters may be due to combination of age and individual characters.
The habit of the teeth in the Ellensburg specimen suggests that addi-
tional material will show more rather than fewer differences separ-
ating this form from the H. mohavense. Neohipparion leptode of the
Thousand Creek Pliocene and an allied form from the Rattlesnake
Pliocene differ from the Ellensburg specimen in the presence of a very
strong anteroexternal ridge on the hypoconid.

Although Hipparion has been listed as occurring in the Maseall,
Middle Miocene, the writer knows of no occurrence that can certainly
be stated to be located within the limits of that formation. Unless
it be true that Hi pparion actually occurs in the Masceall, it seems that
the Ellensburg formation may be of considerably later date than the
beds containing the typical Mascall fauna of the John Day Valley in

eastern Oregon.

MEASUREMENTS
Hipparion Hipparion
condoni, Merychippus, mohavense,
Ellensburg Barstow Ricardo
No. 668 U.O. No. 21459 No. 19785
P,, anteroposterior diameter .._.-.....-------------c----+:- 21 mm. 24.7 23.8
P,, transverse diameter across protoconid ....... Halil 12 11.9
P,, anteroposterior diameter of metaconid-meta-
Fehiaallikel CoCo bi aah alaieesme en eeese eeerror Peer ee rarer ter aes 12. 9.1 14.7
IPoe, Vavssifea mms; CoS \yuCoelal. Xai O (Nl eee ern 31 44 32
M,, anteroposterior diameter ....-......--.---------------+ 17.6 25.4; eee
M,, transverse diameter across protoconid ........ 10.3 10:1. J ae
M,, anteroposterior diameter of metaconid-meta-
Styli) (Comma) <2. -c.n ee. <n ac snece-secsrenceteee =e sates ceneenees 11.2 9:9 ~* ae
Hipparion, Merychippus,
Ellensburg, Barstow
No. 672 U.0. No. 24776
J,, anteroposterior diameter 8.3 ict: ees
I,, transverse diameter -....-.......-.--.-- 93 # #8) ) ==
I,, anteroposterior diameter 8.3 7.7 5
I,, transverse diameter -.....------2-----2----------eeereee 12.1 6.5 ees
I,, anteroposterior diameter .........--.------/------------- 7.4 Sif a eee
I,, transverse diameter -.......-.----+--1:--------ees 12 5:9) at ees

Transmitted June 7, 19165.

Maa ee a
e- i
7 ‘ : ay

Vorumn 7—(Continued).

Pay siobraphy and Sirudtite of the Western El Paso Range and the Southern Sierra

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| 22. The Fauna of the San Pablo Series of Middle California, by Bruce L. Clark (in
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1. New Species of the Hipparion Group from ¢
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2. The Occurrence of Oligocene in the Contra (

Brnee [1 +Clark \ 9. <2 Soo Peas eanee ew AD) sf sy

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VOLUME 6.
. The Condor-like Vultures of Rancho La Brea, by Loye Holmes Miller..._......... 4
. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestera hotel
Nevada, by John C. Merriam. Part I.—Geologic History....-..ccsccssscseccsesesses-oes cael
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Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, b; by

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Note on a Gigantic Bear from the Pleistoyene of Rancho La Brea, by John C,
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. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Desert, a
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8, The Stratigraphic and Faunal Relations of the Martinez Formation to the Chieo
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10. A. New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor...
li, Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern
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12, A Series of Eagle Tarsi from the Pleistocene of Rancho La Brea, by oe
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17. A Fossil Beaver from the Kettleman Hills, California, by Louise Kelinee seceecanannnnne
18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam .......-.c...10-- sorursenenetwe||
19. The Hlastic-Rebound Theory of Earthquakes, by Harry Yielding Reid ............ coeeoneerne

I AN PHO pH

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1, The Minerals of Tonopah, Nevada, by Arthur S. Hakle ...W....-.--sscs--cvserneeess
2. Pseudostratification in Santa Barbara County, California, by George Davis Li
DBC nocacsnestnediiedoleseoncr ust ge opastinnnontbenadedgbun dis oor ya venpush aah tess Laie a eto ee eee re
3. Recent Discoveries of Carnivora in the Pleistocene of Rancho La Brea, by ; Fein €
ROR, (one ela os seecnt adidas a. fanw apd naildtiey wayateton soe 1s Babee UO Rae Me te e ee a ;
4. The Neocene Section at Kirker Pass on the North Side of Mount Diablo, by
Digs CMa oases See ek echon ce nnny sonekpide steer ieratsnse tae deans eee
5. Contributions to Avian Palaeontology from the Pacific Coast of

Lye Holmes) Maer (6.1.26. tec0n) eon -nedtiennned ons sunentas Gov4obn aot seeeniied tanec Mitac ees

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 2, pp. 9-21 Issued June 30, 1915

THE OCCURRENCE OF OLIGOCENE IN THE
CONTRA COSTA HILLS OF MIDDLE 7
CALIFORNIA eee ‘

BY ( ~ og =
BRUCE L. CLARK \ ie
‘ = 4 .
~Stenal_
CONTENTS PAGE
Introduction 9
Agasoma gravidum Beds in the Vicinity of the Town of Walnut Creek ........ ]
VelaiTOmMbON dey OT (GEOCENE))) <2. eeccecce.ccvececesteees tee reecdenc cote eee sees cceeucccevenes-sccescedeeeeuene J

Relation to Arca montereyana Zone (Miocene)
Faunal Relationship of Agasoma gravidum Zone to Arca montereyana Zone 1]
List of Species from Agasoma gravidum Zone of Contra Costa County,

CR TR oy ea a a ee a ee eee 14
Relation of Agasoma gravidum Zone to the Lower Miocene of Southern
CRIES aN a en 15

Evidence Suggesting Correlation of the Fauna of the Agasoma gravidum
Zone of Contra Costa County, California, with that of the Oligocene of
Oregon and Washington .

ISSUUNADUTD YH alse ates Nn rae Sec cn ade Ree eee eB Noerieen lot sw ace de cea necueo bseteeseaeteseeyneadeeeee 2]

INTRODUCTION :

Heretofore only two marine stratigraphic groups, the Monterey
and the San Pablo, have been recognized in Contra Costa County above
the Tejon (Upper Eocene). In the vicinity of San Pablo Bay the
Monterey Group of Professor A. C. Lawson has a thickness of over
five thousand feet, consisting of nine formations, five of sandstone and
four of shale. In the past, three faunal zones have been recognized
in this group; the lowest was described by Dr. J. C. Merriam as the
Agasoma gravidum zone,’ the middle will be referred to here as the
Arca montereyana zone.t| The upper zone is known as the Scutella
brewerlana zone.

1a Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol., vol. 3, no. 16, p. 378,
1904.

1 Arca montereyana Osmont is possibly the same as Arca devineta Conrad.
If this determination should prove correct, the horizon should be known as the
Arca devineta zone.

10 University of Californa Publications in Geology [ Vou. 9

Recently discovered stratigraphic and palaeontologie evidence indi-
cates that the Agasoma gravidum zone belongs to a distinct period
of deposition, and that the time-break represented by an unconformity
between it and the Area montereyana beds above is apparently a
large one. The fauna of the Agasoma gravidum zone is correlated by
the writer with a part of the Astoria series, as described by Dr. Ralph
Arnold and Mr. Harold Hannibal.?

It is only a few years since a marine Oligocene fauna was first
recognized on the Pacific Coast by Dr. W. H. Dall in a paper by
J. S. Diller entitled ‘‘A Geological Reconnaissance of Northwestern
Oregon.’’® The following year Dall,* in a correlation table of the
Tertiary horizons of North America, again placed a part of the Astoria
shale of Oregon in the Oligocene.

It was nearly ten years later before attention was called to marine
Oligocene beds in California. In 1906 Dr. Ralph Arnold’ listed a
fauna from a formation, which he named the San Lorenzo and which
he believed to be of Oligocene age. In 1908 Arnold published the
descriptions of the new species obtained from the San Lorenzo For-
mation and again referred it to the Oligocene.® In the Santa Cruz
folio’ a definite description of the lithology and stratigraphy of the
San Lorenzo is given. The final conclusion was that there is no evi-
dence of a stratigraphie break in the Santa Cruz Mountains between
the Oligocene and the Miocene. It was believed that certain beds,
designated as Transitional Oligocene-Miocene, contained a fauna which
was transitional between the Oligocene and the Miocene.

The first attempt to separate the faunas of the Lower Miocene and
Oligocene in Oregon was by Dr. W. H. Dall.* Dall at that time recog-
nized the inadequacy of his list and the probability of the mixture of
his faunas.

2 Arnold, Ralph, and Hannibal, Harold, The marine Tertiary stratigraphy of
the North Pacific Coast of America, Proce. Amer. Phil. Soc., vol. 52, no. 212,
November-December, 19138.

3 Diller, J. S., 17th Ann. Rept. U. 8. G. S., pt. L, p. 464, 1895.

4Dall, W. H., A table of North American Tertiary horizons correlated with
one another and with those of Western Europe, with annotations, 18th Amn.
Rept. U. S. G. S., pt. Hl, p. 334, 1896-97.

5 Arnold, Ralph, Prof. Paper U. 8. Geol. Surv., no. 47, pp. 16, 17, 1906.

6 Arnold, Ralph, Descriptions of new Cretaceous and Tertiary fossils from
the Santa Cruz Mountains, California, Proc. U. 8. Nat. Mus., vol. 34, no. 617,
pp. 345-385.

7 Branner, J. C., Newsom, J. F., Arnold, Ralph, Santa Cruz Folio, U. 8. Geol.

Surv., no. 163, p. 4, 1909.

8 Dall, W. H., The Miocene of Coos Bay, Oregon, Prof. Paper U. 8. Geol.
Surv. no. 59, p. 11, 1909. :

1915] Clark: Occurrence of Oligocene in the Contra Costa Hills ial

Two important papers published during the last two years have
added considerably to our knowledge of the Tertiary faunas of the
North Pacifie Coast. The first of these was by Dr. C. E. Weaver.’
The second paper, by Arnold and Hannibal,'® undertakes a broader
and more general correlation. Beds which are placed in the Oligocene
are referred to the Astoria series, which is divided into three forma-
tions—the San Lorenzo, Seattle, and Twin River. These formational
names are apparently not used in the hthologic sense but in the
faunal. The lowest of the three faunas is recognized as being equiv-
alent to the San Lorenzo of the Santa Cruz Quadrangle, California.
Beds which are called the Monterey are said to overlie the Astoria
series. An unconformity is inferred between the Monterey and the
Astoria series, but no definite description is given.

Weaver in describing the Oligocene and Miocene horizons did not
recognize any of the older and more general names. Beds, the faunas
of which are equivalent in part at least to the Astoria series of Arnold
and Hannibal, are called by him the Lincoln and Blakeley formations.
The former is referred to the Oligocene, the latter to the Miocene.
Weaver apparently uses the term ‘‘formation’’ in a lhthologie sense.

In a recent paper, Chester W. Washburne™ gives a brief description
of the sedimentary formations in northwestern Oregon. According
to Washburne, no evidence has been obtained in that region which
indicates a stratigraphic break between beds regarded as Oligocene
and those of upper Eocene age. It is stated also that there is no reason,
stratigraphic or lithologic, for the separation of these Oligocene beds
from beds which are considered to be of Miocene age. The evidence
for making the division was entirely palaeontologic, being based upon
the work of Dr. W. H. Dall. It is stated that Arnold and Hannibal
do not agree with this division, since they place the lower part of the
Miocene as recognized by Dall in the vicinity of Astoria, Oregon, as
a part of the Oligocene.

In the Contra Costa hills the beds, which in this paper are referred
to the Oligocene, have heretofore been included in the Miocene and
considered to be a part of the Monterey Group. However, the dis-
tinctness of this fauna has lone been recognized. In 1904 Dr. J. C.
Merriam’ notes that the fauna of the beds referred to the Monterey

9 Weaver, C. E., A preliminary report on the Tertiary palaeontology of
Western Washington, Washington Geol. Surv. Bull., no. 15, pp. 1-80, 1912.

10 Arnold, Ralph, and Hannibal, Harold, op. cit.

11 Washburne, Chester W., Reconnaissance of the geology and oil prospects
of Northwestern Oregon, U.S. G. S. Bull., 590, pp. 1-110, 1914.

12 Merriam, J. C., A note on the fauna of the Lower Miocene in California,
Uniy. Calif. Publ., Bull. Dept. Geol., vol. 8, no. 16, p. 378, 1904.

12 University of California Publications in Geology [ Vou. 9

is separable into at least two zones exclusive of the shale facies. The
following statement is made:

The fauna of the lower division is much more characteristic than the upper;
that is to say, it differs more decidedly from that of the beds immediately above
and below it... . The most characteristic species are Agasoma gravida, Dosinia
mathewsoni, Chione mathewsoni, and Mytilus mathewsoni. ... The lower fauna
is recognized at many places in Contra Costa County, and always near the base
of the series. This faunal division might appropriately be called the zone of
Agasoma gravida.

In the San Francisco Folio,!® which was published very recently
by Professor A. C. Lawson, the beds containing the fauna of the
Agasoma gravidum zone, as defined by Dr. J. C. Merriam, are included
in the Miocene as a part of the Monterey group. For this the writer
is In part responsible.

AGASOMA GRAVIDUM BEDS IN THE VICINITY OF THE TOWN OF
WALNUT CREEK

The unconformity between the Agasoma gravidum beds and the
Area montereyana beds in certain localities in Contra Costa County
is in the Sobrante sandstone, the basal member of the Monterey group
of Lawson. It is best seen in the section of the Monterey a little to
the south of the town of Walnut Creek and only a few miles west of
Mount Diablo. Here the Agasoma gravidum beds outcrop on two
sides of a southeasterly plunging, tightly appressed syncline, resting
upon the Tejon (Eocene) and being overlain unconformably by beds
containing the fauna of the Arca montereyana zone."

On the west side of the syneline, to the southwest of the town of
Walnut Creek and on the west side of San Ramon Valley, the beds of
the Agasoma egravidum zone are about 525 feet in thickness. They
consist for the most part of a fine gray tuffaceous sandstone, which
in some localities has a blueish cast. <A little above the middle of the
section there is a thin bed of a siliceous gray shale. Excellent ex-
posures of these beds may be seen about two miles to the south of the
town of Walnut Creek.

Relation to Tejon—No heavy conglomerates were found in this
section at the base of the Agasoma gravidum beds. The exact lne
of contact between it and the Tejon (Eocene) is uncertain. So far,
no direct evidence has been obtained in any of the sections studied

18 San Francisco Folio, U. S. Geol. Surv., no. 198, 1914.

14 See Geologic Map of Concord Quadrangle, 8. F. Folio, U. 8. Geol. Surv.,
no. 193, 1914.

1915] Clark: Occurrence of Oligocene in the Contra Costa Hills 13

of a stratigraphic break between the Tejon and the Agasoma gravidum
beds. However, in almost every section a typical Tejon fauna was
found not very far below beds containing the Agasoma gravidum
fauna. The great difference between these two faunas leaves very
little doubt as to the presence of a large break.

Relation to Arca montereyana Zone.—The Agasoma gravidum beds,
just described, are overlain unconformably by beds containing an
almost entirely different fauna. These represent the base of the Area
montereyana zone, and contain the following species:

Area montereyana Osmont Ostrea titan Conrad

Marcia oregonensis Conrad Agasoma barkerianum Anderson
Mulinia densata Conrad Crepidula princeps Conrad
Panope estrellana Conrad Fusus stanfordensis Arnold

Pecten, ef. bowersi Arnold

A number of new species were found at this horizon. Of those
listed above, the only one which has been found in the Agasoma
gravidum beds is Panope estrellanus.

The Arca montereyana beds in this section have an estimated thick-
ness of about 800 feet. The basal 100 feet consists of coarse sandstone
in which cross-bedding is very common, together with lenses of con-
glomerate and shale. This is followed by about 100 feet of pearl-gray
shale, above which the beds consist for the most part of a fine gray
sandstone.

The line of contact between the Arca montereyana beds and the
Agasoma gravidum beds is marked by conglomerate and coarse sand-
stone. The conglomerate is lenticular and, in some localities, has a
thickness of from ten to fifteen feet; in other localities it may be
almost entirely absent. The boulders and pebbles found in it were
derived from many sources; both igneous and sedimentary rocks are
present.

The evidence in this section for an unconformity between the
Area montereyana beds and the Agasoma gravidum beds is as follows:
(1) It is suggested by lithology; conglomerates and coarse sandstone
occur along a line of contact, below which there is a sudden change
to a fine sandstone. (2) A contact with irregularities of considerable
size has been observed between these two horizons; in certain loeal-
ities the Agasoma gravidum beds vary in thickness along the strike,
due apparently to erosion; the Areca monterevana beds have long been
known to rest locally upon the Eocene. (3) Fossiliferous boulders

14 University of California Publications in Geology [ Vou. 9

which contain characteristic species of the Agasoma gravidum beds,
are found in the conglomerates at the base of the Arca montereyana
beds. At some localities these boulders are so abundant that one, in
collecting from the matrix of the conglomerate, must be careful not
to gather a mixture of the upper and lower faunas. The writer has
collected ten or more species of the Agasoma gravidum fauna from
boulders in this basal conglomerate and undoubtedly a much larger
number could be obtained. Many boulders are quite angular and
were over a foot in diameter and apparently they could not have been
transported far. It seems possible therefore that they were derived
from cliffs in the vicinity of this beach during Monterey time.

FAUNAL RELATIONSHIP OF AGASOMA GRAVIDUM ZONE TO ARCA
MONTEREYANA ZONE

The best evidence for an important hiatus between the Agasoma
eravidum beds and the Arca montereyana beds is palaeontological.
At present ninety molluscan species are known from the Agasoma
eravidum beds; of these thirty-one, or ever 40 per cent, of the deter-
minable species are new. Over sixty determinable species are known
from the Arca montereyana zone of Contra Costa County; of these
only twelve have been found in the Agasoma gravidum zone. None
of these twelve species common to the two zones are forms that are
generally considered to be good horizon determiners. Fifty-five of
the determinable species of the Agasoma gravidum zone have not been
found in the Areca montereyana zone, and there is nearly an equal
number in the upper of the two zones which have not been found in

the lower.

LIST OF SPECIES FROM AGASOMA GRAVIDUM ZONE OF CONTRA COSTA
COUNTY, CALIFORNIA

Pelecypoda Leda, sp.?
PATCH Ms SP ye As Macroeallista, n. sp.
ATCa, NiSP.; 5. Macroeallista ef. vespertina
Acila, n. sp. (Conrad)
Amiantis, n. sp. Macroeallista? mathewsonii
Cardium lorenzanum Arnold (Gabb)
Cardium vaqueroesensis Arnold Mya, n. sp.
Cardium, n. sp. Mytilus mathewsonii Gabb
Chione, n. sp., A. Mytilus, sp.?
Chione, n. sp., B. Nucula, n. sp., A.
Chione, n. sp., C. Nucula, n. sp., B.
Diplodonta, n. sp. Panope estrellana, Conrad
Donax, sp. indt. Periploma, sp.?
Dosinia whitneyi (Gabb) Pecten, n. sp.

Leda, n. sp. Pecten peckhami Conrad

1915] Clark: Occurrence of Oligocene in the Contra Costa Hills 15

Pecten, sp.?

Phacoides acutilineatus (Conrad)

Pitaria, n. sp.

Psammobia, sp.

Solen, n. sp. aff. parallelus Gabb

Solen curtus Conrad

Spisula occidentalis (Gabb)

Spisula ramonensis Packard MS.

Spisula, sp.?

Tellina oregonensis Conrad

Tellina, sp.?

Tellina, n. sp.

Tellina lorenzoensis Arnold

Thracia econdoni, Dall

Thracia, n. sp.

Yoldia, n. sp.

Yoldia, sp.?

Gasteropoda

Agasoma acuminatum Anderson
and Martin

Agasoma gravidum (Gabb)

Aneillaria fishi Gabb

Bursa mathewsoni (Gabb)

Calliostoma, n. sp.

Columbella, n. sp.

Chrysodomus, n. sp.

Chrysodomus, n. sp.

Crepidula praerupta Conrad

Cerithium, n. sp.

Calyptraea excentrica (Gabb)

Calyptraea radiata (Lamarck)

Canecellaria condoni Anderson

Epitonium, n. sp.

Epitonium, sp.?

Fusinus (Priscofusus) hecoxi
Arnold

Haminea, sp.?

Mioplenia, sp.?

Molopophorus biplicatus Gabb
Molopophorus gabbi Dall
Murex (Ocinebra), n. sp.
Natica (Neverita) recluziana
Petit
Natiea (Neverita), ef. callosa
Gabb
Natica, n. sp.
Natica (Euspira), n. sp.
Natica (Neverita), n. sp.
Neptunea recurva Gabb
Olivella, n. sp.
Olivella, cf. pedroana Conrad
Phalium, n. sp.
Sinum scopulosum (Conrad)
Strepsidura, sp.
Thais, n. sp.
Turbinella, sp.?
Turritella porterensis Weaver
Turris, n. sp., A.
Turris, n. sp., B.
Turris, sp.?
Scaphopoda
Dentalium, n. sp.
Dentalium petricola Conrad
Dentalium, ef. stramineum Gabb
Cephalopoda
Aturia, sp.?
Crustacea
Balanus, sp.?
Anthozoa
Siderastrea, n. sp.
Amphineura
One anterior plate of chiton
Echinodermata
Linthia californica Weaver

RELATION OF THE AGASOMA GRAVIDUM ZONE TO THE LOWER
MIOCENE OF SOUTHERN CALIFORNIA

Before considering the problem of the correlation of the Agasoma

egravidum zone, it is desirable to outline the classification of the marine
Neocene of the Californian area.

The Neocene of California is divisible into two parts by a strati-
graphic break, which occurs somewhere between Middle and Upper
Miocene. This interruption has been referred to by Arnold as ‘‘the
most widespread and important period of diastrophism in the Ter-
tiary history of the Pacifie Coast. ... Its effects are visible from
Puget Sound to Southern California; it is marked by much readjust-
ment, by local faulting and folding, as by general movements of
elevation and subsidence.’’!®

15 Arnold, Ralph, Environment of the Tertiary Faunas of the Pacifie Coast,
in Willis and Salisbury, Outline of Geologie History, p. 241, 1910.

16 University of California Publications in Geology [ Vou. 9

For the purposes of this paper it will not be necessary to consider
the beds, which are above the stratigraphic break to which reference
has just been made. The beds below this unconformity (usually
designated as Lower Miocene) are known by various local names along
the Pacifie Coast. It is still a question whether they form one, two,
or possibly more distinet epochs of deposition. In California two
faunal zones have been recognized in these beds, both of which repre-
sent a littoral facies of deposition. Besides these, there is a fauna
obtained from the diatomaceous shales of the Coast Ranges usually
known as the Monterey shale. This latter fauna has generally been
considered to be contemporaneous with the two littoral faunal zones.
Ilowever, in a recent paper Mr. F. M. Anderson’® has expressed the
belief that the fauna from the Monterey shales of the Coast Ranges
belongs to a distinct and later period of deposition than either of the
two littoral faunas mentioned above. The lower of the two littoral
faunas has been generally known as the Turritella inezana zone; the
upper as the Turritella ocoyana zone. Beds containing the fauna of
the lower zone have usually been called Vaqueros; beds of the upper
zone have been referred to as Vaqueros, Monterey, and Temblor.

The Agasoma gravidum beds cf middle California were first pro-
visionally considered by Dr. J. C. Merriam™ to be near the age of
the Turritella ocoyana beds, referred to above. With the data now
at hand, it would appear that the faunas of the Turritella ocoyana
and the Turritella inezana zones are more closely related than has
heretofore been supposed; that though possibly there may be a strati-
eraphie break between them, as has been reported in several localities,
the faunal evidence would seem to show that the time-break was
probably not a large one. There is apparently a much greater dif-
ference between the fauna of the Agasoma gravidum zone and that
of the Turritella inezana zone than there is between the fauna of the
latter and that of the Turritella ocoyana zone. It is certain that the
fauna of the Agasoma gravidum zone of Contra Costa County belongs
to an older horizon than the Turritella ocoyana zone, and it appears
to the writer to be older than the Turritella inezana zone.

The fauna of the Arca montereyana zone of Contra Costa County
is as old as that of the Turritella ocoyana zone and possibly older.

16 Anderson, F. M., and Martin, Bruce, Neocene record in the Temblor Basin,
California, and Neocene deposits of the San Juan District, San Luis Obispo
County, Proe. Cal. Acad. Sci., 4th ser., vol. 4, pp. 15-112, pls. 1-10, 1915.

17 Merriam, J. C., Fauna of the Lower Miocene in California, Univ. Calif.
Publ., Bull. Dept. Geol., vol. 3, p. 380, 1904.

1915] Clark: Occurrence of Oligocene in the Contra Costa Hills 17

It contains many of the Lower Miocene species, a number of which in
the southern part of the state are found in both the Turritella ocoyana
and Turritella inezana zones.

EVIDENCE SUGGESTING CORRELATION OF THE FAUNA OF THE
AGASOMA GRAVIDUM ZONE OF CONTRA COSTA COUNTY,
CALIFORNIA, WITH THAT OF THE OLIGOCENE OF
OREGON AND WASHINGTON

Accumulating evidence seems to show that there is a faunal break
in Oregon and Washington between the Oligocene and Lower Miocene
which is as great as that in California. The distinctness of the faunas
of these two horizons will be more easily shown when a larger per-
centage of the known species have been described.

The writer has had the opportunity of studying large collections
at the California Academy of Sciences, which were obtained by Bruce
Martin from many of the Oligocene and Miocene localities lsted by
Arnold and Hannibal, Dall, and Weaver. It was by means of these
collections that data were obtained for correlating the Agasoma gravi-
dum beds with the Oligocene of Oregon and Washington.

Two important localities from which Mr. Martin obtained fairly
large collections of very well preserved fossils are from the bluffs
near the town of Pittsburg, Columbia County, Oregon, and on Lincoln
Creek near the boundary line of Lewis and Thurston counties, Wash-
ington. The beds at the Pittsburg locality are classed as Eocene by
Dr. W. H. Dall.*8. It was here that the types Macrocallista pittsbur-
gensis (Dall) and Acila shumardi Dall were obtained. The collection
obtained by Mr. Martin at this locality shows conclusively that this
fauna cannot be classed as Tejon (Upper Eocene), but is equivalent
to what Dall recognizes elsewhere as being Oligocene. The Lincoln
Creek locality is the type locality of Dr. C. E. Weaver’s Lineoln
Formation,'® which he considers to be Oligocene and from which he
lists a number of Eocene species.

The species.in the collection of the California Academy of Sciences
from the Pittsburg and Lincoln localities are listed below. In the
table following are indicated the species common to either of these
localities and the Agasoma egravidum beds of Contra Costa County and
the San Lorenzo of Santa Cruz County.

18 Dall, W. H., Trans. Wagner Free Inst. Sei., vol. 3, pt. 6, p. 1253, pl. 36,
fig. 32, pl. 48, fig. 15, 1903; Washburne, C. W., Reconnaissance of the geology
and oil prospects of Northwestern Oregon, U. 8. G. 8. Bull., no. 596, p. 31, 1914.

19 Weaver, C. E., A preliminary report on the Tertiary palaeontology of*
Western Washington, Washington Geol. Surv. Bull., no. 15, pp. 15-16, 1912.

18 University of Califorma Publications in Geology [ Vou. 9

$ g
fe S) g
a 2 re
PELECYPODA = oc ze
JeMoniley tsNotubanee aol IDEN Vo gee ee rere ee x x
Cardium lorenzanum Arnold x x x
Crassatella washingtonensis Weaver ............ x
Crenella porterensis Weaver ............--.2::2:---+ x
Diplodonta, n. sp. x x
Gily CIM OTS are peers eee teeee oe eneceenen ne ee eee eee x
Leda impressa Conrad ...........2.22::22::esceseeeeeee x x 2 x
Malletia chehalisensis Arnold ....................-- a x x
Macrocallista pittsburgensis Arnold ............ x
Panope estrellana Conrad ..........22.....22000020-- x x
Phacoides acutilineatus (Conrad) ................-- x x
PE RTTG:. TLE SS), eesseeycsce ose soe eeeven eves vacate eee eee Bre aa x x
Spisula ramonensis Packard .........2.....222.-..---- x x
rovoMleval. (Oyama rails) (Gropaeee ysl a ee eee eee x
Solen, n. sp., aff. parallelus Gabb .................. x x
Tellina oregonensis Conrad ..............----..2.------ x x
MblawekaKesttes (xonayelowaal IDM, ca eee renee x ns
GASTROPODA
Agasoma gravidum (Gabb) ..........---------------- x x
PaNaat(cullUleinesitsty sis ot) (Cel 0). 6) eoeeese ere <a x
Calyptraea excentrica (Gabb) ..........---....--.-- = s x x x
Fusinus (Priscofusus) hecoxi Arnold .......... Me x x >
Hemifusus washingtoniana Weaver ............. x x
Miolopophoxus, me Spy 22.se2qc-neceececeneceeseeceeeaeee ees eae ; PRS Sa
Molopophorus galbior Dall eee eee , x
Mioriossatt. tulbercuila tas Giallo esses eeseeeeee see x
WNatiea, recluiziam a: Cty titers: -...-ce-ceeeeee serene Mo ut x x
Natica oregonensis Conrad .........---..------..--0-++- x > ee x
Pleurotoma perissolaxoides Arnold ........... Bes xe x
Seaphander, cf. oregonensis Dall ...............-...- x
Strepsidura californica Arnold .................-- x x
TEUWUTIS,) as Ss Ae oe eae see coe sone sees seeeee reece x x
MDGS as Fy pe a | 8) iy er ere ee ee ee reece shen x x x
Turritella porterensis Weaver ..............-..2.-2 x x Xe

As shown in the above list, sixteen species out of a fauna of twenty-
one obtained from the beds at Pittsburg are common to the Agasoma
gravidum zone of Contra Costa County. Out of a fauna of eighteen
species obtained from the beds of the Lincoln Creek locality eight are
common to the Agasoma gravidum zone of Contra Costa County. A
noticeable feature of the group of species common to the Agasoma
eravidum zone and these northern localities is that a large proportion
of them are fairly highly ornamented types, belonging to genera the

1915] Clark: Occurrence of Oligocene in the Contra Costa Hills 19

species of which are generally considered to be especially good hor-
izon determiners, such as Agasoma, Molopophorus, Priscofusus, and
Turritella.

The Oligocene fauna, as found at Pittsburg, Oregon, and Lincoln
Creek, Washington, is fairly well represented throughout the western
part of Washington and the northwestern part of Oregon. This fauna
is everywhere very distinct both from that of the Eocene and from
that of the typical Miocene. The following conclusions are based
upon a large number of localities in Oregon and Washington, from
which Mr. Martin obtained representative faunas of the Oligocene and
Miocene formations.

Nearly half of the determinable species from the Agasoma eravl-
dum zone as known in Contra Costa County, California, are found in
the Astoria series, as recognized by Arnold and Hannibal in Oregon
and Washington, which includes the Pittsburg beds and the Lincoln
Formation referred to above. The following are some of the described
species which are common to the two. (Those species marked with an
asterisk are believed to be characteristic of the Oligocene. )

Cardium lorenzanum Arnold *Aoasoma acuminatum Martin and
Anderson

*Macrocallista mathewsonii (Gabb) ec iahn Hen CaBh
A “WATE 5 TAD

*Mytilus mathewsonii (Gabb)
Panope estrellana (Conrad)
Pecten peckhami Gabb
Phacoides acutilineatus (Conrad)
Solen eurtus Conrad
*Tellina lorenzanum Arnold

*Bursa mathewsoni (Gabb)
Calyptraea excentrica (Gabb)
*Fieus pyriformis Gabb
*Molopophorus biplicatus Gabb
*Molopophorus gabbi Dall

Telli vo : *Fusinus (Priscofusus) hecoxi
ellina oregonensis Conrad (Arnold)

*Agasoma gravidum (Gabb) *Turritela porterensis Weaver

Besides the species listed above, a number of new species have been
found which are common to the two horizons. Some of these are
Cardium, n. sp., Chione, n. sp., Pitaria, n. sp., Pecten, nu. sp., Solen,
n. sp., Spisula, n. sp., Solen, n. sp. aff. parallelus Gabb, Natica, n. sp.,
Turris,n. sp. A., Turris, n. sp. B., Dentaliwm, n. sp.

Of the species which are common to the Agasoma gravidum zone
of Contra Costa County, California, and the Oligocene of Oregon and
Washington, Cardium lorenzanum, Tellina lorenzanum, and Fusinis
hecori were first described from the San Lorenzo of the Santa Cruz
Quadrangle. Turritella porterensis was described from the Porter beds
of Washington, which beds Arnold correlates with his San Lorenzo and
which are placed by Weaver in the Blakeley Formation. Molopophorus
gabbi was deseribed by Dall from the Astoria beds of Oregon.

20 University of California Publications in Geology [ Vou. 9

The following species, which are believed to be characteristic of
the Oligocene and which are very common in the Oligocene in the
north, were originally described from the Agasoma gravidum beds of
Contra Costa County: Macrocallista? mathewsonti (Gabb), Mytilus
mathewsonn Gabb, Agasoma gravidum (Gabb), Ancillaria fishi Gabb,
Bursa mathewson (Gabb), Ficus pyruformis Gabb, Molopophorus
biplicatus Gabb. Some of these, Macrocallista? mathewsonti, Mytilus
mathewsonn, Agasoma gravidum, Molopophorus biplicatus, have been
reported in the Lower Miocene (Turritella ocoyana and Turritella
inezana zones). The writer has had an opportunity to examine most
of the forms determined as these species from the Miocene, and with
possibly one or two exceptions these determinations are believed to
be wrong.

Much remains to be done before the faunal zones of the marine
Oligocene of the west coast are definitely outlined. Arnold and Han-
nibal’®? have recognized three faunal zones in their Astoria series—
the San Lorenzo, the Seattle, and the Twin River formations. The
San Lorenzo horizon is correlated by them with the San Lorenzo
formation of the Santa Cruz Mountains in California. Nearly all of
the new species originally deseribed by Arnold from the San Lorenzo
of California have been found in the San Lorenzo of Oregon and
Washington. A number of these are also found in the Seattle beds.

The fauna of the Lincoln Formation described by Professor C. E.
Weaver is considered by Arnold and Hannibal as the equivalent of
the San Lorenzo horizon. The Porter beds in the vicinity of the town
of Porter, originally referred to the Miocene by Weaver, are at least
in part Olhgocene and apparently belong to the San Lorenzo horizon.

Much remains to be done before the faunal zones of the marine
Oligocene of the west coast are definitely outlined. For this reason
only a very general statement as to the probable position of the
Agasoma gravidum fauna in the Oligocene section of the west coast
will be made. The fauna of the Agasoma gravidum zone is possibly
somewhat younger than that of the San Lorenzo. Certain species
which are found in the Santa Cruz Mountains and in Oregon and
Washington, and which are thought to be characteristic of the San
Lorenzo horizon, have not been found in the Agasoma gravidum beds.
Also the lack in the fauna of the Agasoma gravidum beds of certain
Eocene species found in the San Lorenzo horizon of Oregon and
Washington, is quite noticeable. However, this evidence is negative,

20 Arnold, Ralph, and Hannibal, Harold, op. cit., p. 579.

1915] Clark: Occurrence of Oligocene in the Contra Costa Hills 21

and when a larger fauna is obtained from the type section of the San
Lorenzo it is not at all improbable that these beds may be found to be
equivalent, in part at least, to the Agasoma gravidum beds of Contra
Costa County.

SUMMARY

1. In Contra Costa County, California, beds containing the fauna
of the Agasoma gravidum zone are unconfcrmably below those con-
taining the fauna of the Arca montereyana zone. This uneonformity
is believed to be more than local and represents the line of division
between Miocene and Oligocene.

2. In California there is apparently a very marked difference be-
tween the Agasoma gravidum fauna and that of the middle and lower
Miocene. The faunal break between the Oligocene and Miocene in
Oregon and Washington appears to be as great as in California.

3. The fauna of the Agasoma gravidum zone of Contra Costa
County may possibly belong to a higher horizon in the Oligocene than
the typical San Lorenzo. The evidence for this statement is chiefly
negative; future work may show a closer relationship to the San
Lorenzo.

Transmitted April 23, 1915.

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17 ai ;
EPIGENE PROFILES OF THE DESERT

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ANDREW C. LAWSON

Nov 16 1916

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 3, pp. 23-48, pls. 1-2, 4 text figs. Issued November 6, 1915

THE EPIGENE PROFILES OF THE DESERT*

BY

ANDREW C. LAWSON

CONTENTS
PAGE
Rainless Regions .................. BR ee aes em 8 SE re Ae ade a Pe eee 23
LENS T HRSA NS ee 25
le mentss.Oils Gee LOL Ge eac Sec cece ve tec aeeed cases eee cer ceecees ooe=cececee ete cccgesee eecseceeeos oot eeee 25
Degradation 28
Alluviation 30
Truncation 31
PIUHe Me SUNG OMS UTA CO sees caste oven sen eee oencecneet ss venn nanss obeesece cacteassiacbidacdeeciq-ceseeseeeceecs= 32
The Panfan stage of the Geomorphie Cyele of the Desert —...................... 33
LAB ei(eh Reyb oe bea Wel 25 0 cl ene nea ee ee ED 34
seh eveAslnival ad eEmib amikim On t= 222-2. erece Fo aoe osc cone van ct ecg sacecscsus seeds qescscseUesacsescesceazeeece 38
ple BS Lillo ale Yes 2a URAEST: Tay ees a erence ce Aes Me sn Sc Seago one <scaee eco seveceueeesesuseee=s ate 42
TORING: VOT GARG EN aN. ES eS me a eg a SE Se 44 -

RAINLESS REGIONS

In a rainless region an uplifted land-mass, an orogenic bloek, is
subject to degradation by:

1. The process of mechanical disintegration at the surface due to
differential dilations and contractions under varying temperatures ; (2 )
the gravitational transportation of the fragments thus detached from
higher to lower levels; (3) the transportation by the wind of such of
these detached fragments as may be small enough to be removed: (4)
the corrasive action of wind-moved detritus and the removal of the
products of such corrasion by the wind.

The relative efficacy of these processes in a purely @ priori dis-
cussion depends altogether upon what assumptions are made. If, for

*Read before Geological Society of America at the Berkeley Meeting, Aug.,
1915.

INV FR 107;
( NOVLZE 1915

24 Unversity of Califorma Publications in Geology [ VoL. 9

example, we assume that our orogenic block is composed of fine-grained
incoherent rock and assume further the prevalence of powerful winds,
then the last two of these processes might well be most important
agencies of degradation. But if we assume that our orogenic block is
composed of coherent, hard, elastic rock, then the products of mech-
anical disintegration would in general be of such a size as to be but
slightly affected by the wind, and the first two processes would be
almost the only agencies concerned in the degradation of the uplifted
mass. It is the latter case, the effect of mechanical disintegration and
gravitational transportation, that I desire here to discuss briefly as
an introduction to the consideration of more complex conditions in
the later part of the paper. For the purpose of simplifying the dis-
cussion I will further assume that the mountain is lithologically and
structurally homogeneous.

Under the conditions assumed, our uplifted block may have initial
slopes which are (1) less than the slope of repose for loose material,
or, (2) greater than the slope of repose. The gentler slopes will remain
unaltered throughout the persistence of the rainless climate. The
surface will of course be at first subject to mechanical disintegration,
but in the absence of any transporting agency the products of dis-
integration will encumber the firm rock and protect it from further
attack. There can be no change of slope due to degradation. The
steeper slopes, on the other hand, cannot retain the fragments shed
by disintegration, and these lodge at the base of the slope in the form
of talus. The slope of the talus thus becomes the limiting slope of
all mountain facets evolved under such conditions. If we suppose a
steeper slope to come inte existence, as for example by repeated
faulting, the disintegration of the surface and the direct action of
gravity will give rise to a talus at its base. As the latter grows it
maintains the constant slope of repose of loose material; but its upper
edge encroaches upon higher and higher parts of the battered scarp.
While this encroachment is in progress the batter of the searp ap-
proaches the slope of the talus; and when the two coincide the combined
slope of the battered scarp and talus becomes the final, unchanging
mountain front. The talus ceases to grow and the rock slope above
ceases to diminish, the loose fragments on both lying at the limiting
angle at which gravity will move them.

During the encroachment of the talus upon the battered scarp the
latter has been reduced in acclivity by more active recession in the

1915] Lawson: The Epigene Profiles of the Desert 25

upper than in the lower part.! The recession has been progressive
with the growth of the talus, and the portion of the battered scarp
which becomes buried is therefore a parabolic curve, the volume of
the talus being assumed equal to the volume of the rock in place,
while the portion which remains above the talus maintains a straight
slope. The development of the final combined facet from the initial
scarp is shown in the diagram, figure 1.

Yyy
TUE
of
Figure 1.—Under rainless conditions a mountain face OR would be reduced
to OPR,, the lower curved portion of which OP would be burried in talus OSP.

The combined rock and talus slope SPR, is the unchanging profile under the
assumed conditions.

In the foregoing statement it is of course not implied that the
talus profile is found only in rainless climates; it may and does oceur
under humid conditions, but here it is a temporary phase of the geo-
morphic evolution, whereas under rainless conditions it is a permanent
and characteristic feature of mountain fronts.”

ARID REGIONS

Elements of the profile—The seant rains of the arid regions are
sufficient to differentiate sharply the epigene forms there displayed
from those deduced above as characteristic of the rehef of a rainless

1 This is due, of course, chiefly to the fact that the amount of disintegration
is a function of the extent of surface exposed, and that this is greatest at the
top of the scarp where it intersects the reverse slope or a gentler slope in the
same direction, but if the searp be high it may also be due partly to larger
contrasts of temperature in higher altitudes,

2 This was written before the appearance of Lane’s abstract dealing with
the same profile in Bull. G. 8. A., Vol. 26, No. 1, p. 75.

26 University of California Publications in Geology [ Vou. 9

region. The rain wash co-operates with gravity and transportation is
far more efficient. The rock slopes are generally much less than the
angle of repose of loose material, the talus is replaced by broad alluvial
fans, and for every enclosed basin there is the aggradational flat of
the playa. For mountains of approximately homogeneous rock the
epigene profile thus comprises three elements: (1) The rock slopes,
having an angle of less than 35°; (2) the alluvial fan slope rarely
exceeding 5°; and, (3) the flat of the playa.

In general these three elements of the profile are easily diserimin-
ated one from the other; but in certain cases the angle of the rock slope
approaches that of the alluvial fan and the two may be confused.
Similarly where the alluvial fan is very flat it may not easily be dis-
tinguished in its lower part from the playa. In many desert valleys
the playa is located at one end, toward which the drainage flows, so
that the fans from the two sides meet in the central part and there is
no playa element in the profile for long stretches.

The proportion between the length of the rock slope and that of
the fan slope varies greatly. The fans are composed of the detritus
washed down from the rock and, as they grow, they rise about the
mountain flanks and steadily diminish the extent of the rock slopes.
Ultimately the upper edge of the fan reaches the crest of the mountain
and there is no farther addition to its surface. A small alluvial
embankment on the flank of a mountain ridge is, therefore, significant
of an early stage of the degradational process; and a large embank-
ment extending nearly or quite to the crest indicates a late stage.
In the deserts of the Great Basin both extremes may be observed.
At Genoa, for example, there is a bold, high mountain front of bare
roek with a small embankment at its base, and in places none at all.®
At Cima in Southern California the mountain ridge is almost com-
pletely buried in its own alluvial waste. From this variable quanti-
tative relation of rock slope and alluvial slope it may be safely
inferred that the mountains of the region, considered as features of
the relief, are of diverse age. On the basis of this relation it is
possible to classify the desert mountains chronologically. Some came
into existence so long ago that their rock slopes have been almost
entirely buried in their own waste; while others have had their origin
so recently that the effect of aggradation about their flanks is relatively
slight. Between these extremes a graded series may be recognized
significant of a time-sequence. This criterion for the chronological

2 Bull. Seism. Soc. Am., Vol. II, No. 3, Sept., 1912; U.S. G. S. Prof. Paper 73,
p. 189, 1911.

1915] Lawson: The Epigene Profiles of the Desert 2

classification of the salient features of the relief of the desert may
attain a notable degree of exactitude if mountains lithologically similar
be compared within the same climatic province.

The degree of acclivity of the epigene slopes of the desert is, on
the other hand, no indication of the stage of advancement of the
degradational cyele. Under humid conditions hard rocks that are sus-
ceptible of chemical decay, and so form soil, tend to acquire more and
more gentle slopes as time goes on. A steep slope in such rocks is
indicative, in general, of geomorphic youth, whereas a gentle slope
is characteristic of old age. In the desert, however, hard rocks present
persistently steep slopes throughout the entire period of their degrada-
tion. The epigene rock slopes appear to be just as steep in old residual
mountains, almost buried in alluvium, as in youthful mountains with
but a small embankment of detritus at their base; and it will be shown
that they are in reality somewhat steeper.

If the mountain mass be heterogeneous the rock slope may not be
uniform, and it may so far depart from the law governing the slopes
of homogeneous material that it will assume temporarily the form of
a vertical chff. This is particularly well exemplified where a hard,
resistant stratum lies at low angles upon soft beds, as in the case of
the Vermilion Cliffs. Here the factors of heterogeneity and structure
dominate the degradational process and the climatic control is relatively
shght. The result is an escarpment which is not peculiar to the desert,
but which may equally well be produced in humid climates, where the
same structure and lithologic heterogeneity prevail, as is exemplified
in the Niagara escarpment.

But even where the condition of approximate homogeneity obtains
it is possible that other agencies than those noted may modify the
profile. The wind may be both a transporting and a corradine agent,
making for aggradation in one place and degradation in another.
While this agency is recognized as of possible importance in regions
where powerful winds prevail, particularly where mountains are largely
composed of soft, fine-grained, incoherent rocks, it will not here be
further considered. The wind, in regions of hard elastic rocks such
as are commonly found in the ranges of the Great Basin, is an
extremely inefficient agent in the evolution of the profiles of the relief.
It is concerned chiefly with local transport of the silts and sands of
the playas and with fitful whirling of sand over the fan slopes. The
occasional sandstorms doubtless carry notable quantities of fine sand
from one part of the desert to another and to regions beyond its

28 University of California Publications in Geology [ VoL. 9

confines. But the wind thus employed plays almost no part in the
direct reduction of the rock slopes, in the building up of the fans or
in the filling of the playas, the processes which it is the purpose of
this paper to discuss.

Degradation.—The encroachment of alluvial embankments upon the
mountain slopes from which they are derived is a general phenomenon
peculiar to the desert. To arrive at a proper appreciation of the pro-
cess of encroachment we must first consider the degradation of the rock
slope. The waste of mountains in arid regions is effected, as is well
known, chiefly by the mechanical disintegration of the surface due to
differential dilatation and contraction. The chemical decomposition
of the rocks, due to bacterial action, which so largely contributes to
the formation of soil in humid regions, is here relatively insignificant.
The degradational process is one of transportation of the products of
disintegration to lower levels. Corrasion by running water is quite
a subordinate part of the process except in those ranges which are
so high as to have a relatively abundant precipitation upon their
summits. The streams thus fed corrade and deposit in accordance with
the general laws so admirably elucidated by Gilbert. But in most
cases the quantity of detritus shed from the sides of the canons
increases faster than the enlargement of their carrying capacity due
to the widening of their catchment area, so that early in their career
they become habitually incapacitated in their lower stretches, and
build up fans or cones of detritus which extend well up into the
trunk canon, forming accentuated features of the general alluvial
embankment on the flanks of the mountain. If we confine our
attention to the movement of detritus upon the slopes, rather than
in the line of. these exceptional streams, the rains which supply the
transporting ageney are characteristically of brief duration, local and
violent. Practically all the reduction of the rock slopes and all con-
tribution to the alluvial embankments, whether apexing in the line
of perennial streams or not, is effected at these brief and infrequent
periods of heavy downpour. When the rock slopes have once been
reduced to an angle less than the angle of repose of loose material,
the removal of the fragments upon their surface is conditioned by
their size and shape. Should they be prevailingly rotund the frag-
ments would move down a gentler slope than if they were irregularly
prismatic. To simplify the discussion I shall assume that rock frag-

4Geology of Henry Mountains.

1915 | Lawson: The Epigene Profiles of the Desert 29

ments in general are irregularly prismatic in shape, which assumption
agrees with observation.

For a given size of fragment the ease with which it may be moved
diminishes with the decrease of the angle of slope at the place where
it rests. Finally a minimum or limiting angle is reached below which
the fragment cannot be moved. This limiting angle thus becomes a
constant feature of that portion of the slope, say near the top of the
slope, throughout all its future degradation under the assumed climatic
conditions. For, if the angle of slope become lower, this and other
similar sized fragments would encumber it and protect the underlying
rock from further disintegration, and degradation would cease. But
the fragments shed from a rock slope vary greatly in size, and those
which determine the angle of slope are the spauls of maximum size,
or perhaps better, the maximum order of size. All loose detritus shed
from the rock slope of less order of size is readily carried down the
slope in times of cloud-burst. Those of the maximum order represent
the limit of size that can be transported. It may be presumed that
rocks similar as to lithology and structure shed fragments of about
the same maximum order of size, and, therefore, have slopes of about
the same angle for similar parts of mountain fronts; whereas dissimilar
rocks shed fragments the maximum order of size of which may differ
greatly.

But the angle of slope for the upper part of a mountain front in
homogeneous rock is not necessarily the angle at the lower part of the
same declivity. It is clear from the bare character of the desert fronts
that the sheets of water which wash down the detritus in times of
cloud-burst are underladen; otherwise there would be a residue of
debris left behind and the slope would be undergoing alluviation and
not degradation. The fact that the flowing water is underladen
and that the volume of water increases in an arithmetical ratio as
it descends determines an acceleration of velocity toward the lower
part of the rock slope. This in turn determines that spauls of maxi-
mum order of size may be moved on a lower angle of slope than at
the top of the slope where the velocity is less. A lower angle is,
therefore, developed at the lower part of the rock slope. This in turn
tends to check the increase of velocity; but, in view of the fact that
the slopes are bare and that the water which keeps them bare is
underladen, it is evident that the acceleration of the velocity while
lessened is not inhibited. Now in any desert range, as the rock slope
shortens by the rise of alluvium on its flank, the contrast between the

30 University of California Publications in Geology [ Vou. 9

velocity and volume of water near the top of the rock slope and near
the bottom steadily diminishes, so that the angle near the bottom of
the shortened slope is greater than at earlier stages of longer slope;
while the angle near the top of the slope remains constant. It follows
from this that the general angle of the shortened slope, from top
to bottom, is higher than for the earlier longer slope.

In this deduction we have the explanation of the observational
faets: (1) That the hard-rock slopes of desert ranges which shed
large spauls are steep, while those which shed small fragments have
a low angle; (2) That ranges composed of hard rock, which are thus
naturally steep, maintain their steepness as long as the rock slopes
endure. We discover, moreover, that they become gradually steeper
with age, the shght upward coneavity approximating more and more
a straight profile as the rock slope becomes shorter. There is, however,
notwithstanding this straightening of the concavity of the profile, a
persistent tendency to over-steeping at the very top of the rock slope,
where the gravitative work of moving fragments has little aid from
flowing water.

Alluviation Assuming the correctness of the hypothesis that the
angle of the epigene rock slope in the desert is determined by the
maximum order of size of the rock fragments shed from its surface
by mechanical disintegration, and, therefore, after adjustment does not
diminish throughout the entire period of its recession, we may apply
it to the development of the mountain profiles. There is abundant
evidence that, in the geological epoch of which the present forms a
part, but of which the beginning is indefinite, the great alluvial fans
which flank most of the mountains of the Great Basin have been
steadily growing. For the greater part of this growth the slope of
the surface has been approximately constant for every embankment.
The increments of growth have, therefore, been of the nature of
additions of uniformly thick layers of detritus to the top of the
embankment. For each layer thus added to the embankment an
equal volume, less the voids, has come from the mountain front. In
general, therefore the average vertical cross-section of the embank-
ment may be considered for the purpose of this discussion to have the
same area as the average cross-section of rock removed from the
mountain front, if we ignore wind action. The growth of the alluvial
embankment proceeds, however, not only upward by the accretion of
successive layers, but also horizontally by the increasing extent of
the layers. Each layer added to it extends farther toward the crest

1915] Lawson: The Epigene Profiles of the Desert 31

of the range than the preceeding layer and so diminishes the height
and breadth of the rock slope, the recession of which is at all stages
limited by the upper edge of the embankment. The rock surface
below this upper edge becomes fixed in position by burial.
Truncation.—lIt follows from this that the buried slope is a shelf
or bench cut into the mountain, the inclination of which is somewhere
between that of the still exposed rock slope and that of the alluvial
embankment. This relation is shown in the diagram, figure 2. The
upper limit of the buried bench, the upper edge of the alluvial
embankment and the lower limit of the subaerial front are coincident
at all stages of the general process. When the edge of the alluvium
reaches the crest the subaerial front has disappeared. What is true

R, SR

Figure 2.—If the surface of the alluvial embankment OS rises to PS,, the
rise is coincident with, and due to, the recession of the mountain front from
OR to PR, The upper edge of the embankment migrates from O to P, and
the rock-eut bench OP is evolved, but is buried as fast as it is cut.

of one side of the mountain ridge is true of the other, so that the rocky
crest disappears by the meeting of the feather edges of the alluvial
embankments, or rather by their coalescence with the unmoved pro-
ducts of the disintegration of the crest rock. Thus, if the mountain
be lithologically and structurally homogeneous, it is reduced by trunea-
tion to a low rock ridge with symmetrical slopes wholly buried by
alluvium, which on either side is wedge-shaped in cross-section, the edge
of the wedge being at the crest and the butt out in the valley. The
upper surface of this alluvium is a gentle slope of great stability for
the prevailing climatic conditions.

But homogeneity is rarely realized in mountain masses and the
heterogeneity varies the rate of the process in different parts and
diversifies the ideal symmetry of the result. Owing to differential
disintegration and recession, one part of the rock crest may disappear
while another portion is salient, and the migration of the lowering
rock crests may proceed unevenly. Similarly, resistant portions of

32 University of California Publications in Geologr [ VoL. 9
y gy

the mass become shoulders and these are usually isolated in the rising
flood of alluvium, as it creeps up the slope, and appear as island-like,
conical rock hills protuberant above the slope. This diversity in
plan and in profile is usually notable in the incomplete stages of the
general process. At completion all the rock crest has disappeared,
but the lne of meeting of the opposing embankments may remain
sinuous. Many of the island-like conical hills become eventually
buried; but others that rise above the ultimate limit of the alluvial
slope remain, of course, protuberant, till as local centers of recession
and alluvial distribution they waste slowly away, and become mere
patches of the bedrock obscured by the residual unmoved products
of disintegration, nearly, but not quite flush with the general slope.

Under exceptional conditions the resultant profile may be asym-
metric. For example, if the initial profile of the mountain be steep
on one side and so gentle on the other that alluvial debris cannot be
transported over it, then the reduction of the mass will proceed on
the steep side only. When the rock surface on this side has been
wholly buried by alluvium and the process of reduction has come to
an end, the profile will be that of the fan slope; but on the other
side it will be that of the initial slope, although the surface may be
encumbered by the sedentary products of disintegration.

The Resulting Surface—The result described has been attained
in southern California; and various stages of the process may be
observed throughout the Great Basin. It is a stage of geomorphic
development at which the processes of degradation and aggradation,
in so far as they are due to the agency of water, both almost cease.
There are no exposed rock slopes to be degraded and the embank-
ments can receive no farther increment. The slopes of the latter are
close to the minimum angle for transportation and therefore are not
themselves susceptible of vigorous attack. With the disappearance
of the rock crest the process of degradation changes from one of
relative rapidity to one of extreme slowness. The wind doubtless tends
to modify the result, but in the Great Basin this tendency is extremely
ineffective; and no important modifications have been observed to
affect any stage of the general process or the result, except that locally
sand derived from the playas may drift over the alluvial slopes in the
form of dunes, which may thus be partially incorporated into the
growing embankments.

The symmetry of profile which is attained in the normal process
of concurrent degradation and aggradation in the desert is of course
a symmetry of angles of slope. It does not extend to the length of

1915] Lawson: The Epigene Profiles of the Desert 33

the slope. This quantity is determined by the distance between the
ultimate crest of the degraded buried range and the median line of
the ultimate aggraded valley on either side. If these distances are
unequal, then the playas in the valleys stand at different altitudes,
the longer slope reaching out to the lower valley. It follows from
this that difference of altitude of the playas on the two sides of a
symmetrically sloped range introduces no element of instability into
the profile. The playas represent the bottoms of distinct enclosed
basins, but when the general condition above outlined has been attained
there is no tendency for the lower basin to capture the higher, so long
as the climatic conditions remain constant. Such capture may be
effected in part by the migration of the crest of an initially asymmetric
or heterogeneous range as an incident of the general process, but once
the rock crest vanishes the tendency to migration ceases and capture
is no longer possible. The surface thus evolved is, in its ideal com-
pletion, wholly one of aggradation, a vast alluvial fan surface to which
for convenience in discussion I propose to give the name panfan.

The Panfan Stage of the Geomorphic Cycle of the Desert—The
panfan may be regarded an end stage in the process of geomorphic
development in the same sense that the peneplain is an end stage of
the general process of degradation in a humid climate. The peneplain
closes the eyele of degradation and is a cut surface; the panfan
closes a eyele of degradation and aggradation, is evolved by both
cutting and filling, and is a built surface. Like the peneplain, the
panfan is rarely observed in its ideal completion. The time required
for its completion is so long that diastrophie or climatic changes
usually interrupt the process, and even where it escapes those inter-
ruptions the final result is subject to destruction by the same changes.
We may not expect, therefore, to find the panfan a prevalent feature
of the relief of deserts which have been subject to such diastrophie
and climatic vicissitudes as have from time to time overtaken the Great
Basin or portions of it. Exceptionally, however, it does occur, as in
parts of southern California; and in various stages of incompletion
is one of the commonest features of the desert.

The recognition of the panfan as a phenomenon to be classified is,
however, not so important as is the perception of the process® whereby

5 This process has been fully recognized by Sidney Paige in his paper
“«Rock-cut Surfaces in the Desert Ranges,’’ Journal of Geology, vol. 20, 1912,
and he has the honor of first summarily stating it. The conclusions set forth
in the present paper may be considered as an amplification of his observations,

although they were arrived at independently, and are, therefore, a corrobora-
tion and not merely a restatement of his views.

34 University of California Publications in Geology [ Vou. 9

it is evolved, or the conception of it as a quasi limiting stage of the
degradation cycle of the desert. Appreciation of the process enables
us to understand certain features of the desert relief which are other-
wise unintelligible; and without the concept of the desert cycle, as
here defined, it is impossible to read the geomorphic history of such
regions.

From the foregoing discussion it is apparent that bold relief in
the desert is subdued partly by degradation and partly by aggradation
in reciprocal relation, and that the degradational process produces two
rock surfaces, one of which vanishes at the close of the cycle while the
other then attains its maximum extent. The former may be referred
to as the subaerial front and the latter as the suballuvial bench.
Neither of these rock surfaces is in evidence at the panfan stage of
the cycle. The subaerial front has been reduced to nothing and the
suballuvial bench is, as at all stages, buried. If, however, there be
introduced at some part-way stage a diastrophic movement which not
only interrupts the normal course of the cycle, but also promotes the
destruction of the alluvial embankment, then we may by resurrection
have the suballuvial bench revealed as an element in the visible
profile. Such stripping of the fans might be effected by faulting or
doming which would inerease the angle of the surface slope. A
general elevation of the region without local faulting or doming might
produce the same result, if precipitation upon the summit region were
thereby increased to the extent of supplying streams competent to
dissect the fans.

Such diastrophie or climatie interruption of the normal course of
the desert cycle, resulting in the stripping of the upper parts of the
embankments, affords the probable explanation of certain broad rock
terraces which are found on the flanks of some of the desert mountains
of California, Nevada, Arizona, New Mexico and Mexico.

Such rock terraces have been described by MecGee,® who ascribed
their origin to sheet flood erosion, and by Paige,* who dissents from
McGee’s hypothesis of sheet flood erosion and correctly interprets
them as resurrected surfaces due to the stripping ot the alluvium
which once rested upon them.

The Suballuvial Bench.—The general genetic relations of the sub-
alluvial bench having been stated, some details of its configuration and
of the law governing its development may briefly be discussed. Neither

6 Bull. Geol. Soc. Am., vol. 8, pp. 87-112, 1897.
7 Loc. cit.

1915] Lawson: The Epigene Profiles of the Desert 35

in the foregoing discussion nor in that which follows is any assumption
made at to the mode of origin of the initial mountain masses of which
the present ranges, of the Great Basin for example, are the degraded
remnants. We may begin at any immature stage of the eyele which
culminates in the panfan, and from observed facts deduce conclusions
which are independent of the original configuration of the relief and
of the genesis of that relief. These conclusions take the form of a
prediction of what results will ensue if the existing conditions eon-
tinue and a statement of what has happened during the persistence
of those conditions in the past. For such a starting-point we may take
any ordinary basin range with its characteristic steep subaerial front
and flanking alluvial embankment. For simplicity I shall assume first
that the mountain front considered is the edge of a flat-topped plateau
or mesa of homogeneous, strong rock. As the subaerial front recedes,
the surface of the embankment rises parallel to itself, but at a dim-
inishing rate owing to (1) the increasing breadth of the alluvial slope
and (2) the decreasing height of the prism of material taken from

Figure 3.—Recession of front of a mesa from OR to T. The embankment
is built up by smaller and smaller increments in equal times owing to the
diminishing height of the front and the increasing width of the embank-
ment. But the recession of the front is at a uniform rate; therefore the
rock-eut bench OPT is a hyperbolic curve convex upward.

the front and added to the embankment. The rate of recession of the
subaerial front is, however, uniform and it results from this that
the suballuvial bench is a curved surface convex upward, defined hy
the locus of the intersection of the fan surface and the surface of
the subaerial front. This relation may be expressed mathematically
by reference to the diagram, figure 3. The profile with which we
start is “ROS, of which TR is the level plateau summit, /?}O is the
subaerial front and OS is the surface of the alluvial fan. R,P is a
second stage of the subaerial front and PS, is the fan surface at the
same stage. A is the angle which the subaerial front makes with the
horizon and B is the angle of the alluvial fan. OP is the suballuvial
bench cut in the transition from the first stage to the second. Let
a end y be the oblique coordinates of the curve OPT, the origin of

36 University of California Publications in Geology [ Vou. 9

which is O. For any point P on the curve, the areas ORR,P and
OSS,P are equal. From this it follows, by a mathematical treatment
which Professor T. M. Putnam has kindly carried out for me, that
the equation of the curve OPT is

sin B cos A

= 5 i

sin A ey ay cos B

The curve OPT, for the assumed condition of a flat-topped mesa, is

2(OR — y) —32?

a hyperbola to which the limiting surface of the fan is tangent at
the point 7’, where the hyperbola intersects the mesa surface.

It is apparent from this, that if the mesa be very broad rela-
tively to its height, the suballuvial benches eut on both sides of
an elongated mountain block might intersect the surface of the mesa
short of the median line, so that on the completion of the process of
degradation, the central part of the resulting stable profile would
be that of the original mesa. If the mountain block be relatively
narrow, and this appears to be the common ease, then the suballuvial
bench will not intersect the mesa surface, but will meet the corres-
ponding bench approaching from the other side at some point below
the level of the summit.

We may now vary our assumption as to the initial form of the
mountain. If instead of being a mesa its cross-sectional area from the
center to the edge O be less than that shown in the diagram, then
the fan surface will rise more slowly and the bench will be flatter
without changing the character of its curvature. If, as is usually
the case, the mountain mass be higher at its center than on its margin,
so that the cross-sectional area be greater than that of the diagram,
then the area ORR,P of one stage of the process may become suffi-
ciently greater than the similar area of the next preceding stage to
cause each successive layer added to the surface of the fan to be
thicker than the preceding layer, and the curvature of the bench will
be coneave upward. It thus appears that for the same width of
valley some suballuvial benches may be convex and others concave
upward; and that the condition which determines the convex curve
may change to the one which determines the concave curve, so that
the resulting bench may be coneavo-convex. In order that the bench
should be a straight slope, the fan would have to rise by equal
increments in equal times throughout its entire growth, and this is
a rare and accidental case.

It is further apparent that the character of the suballuvial bench
is a function of the width of the valley, OS, in which the detritus

1915] Lawson: The Epigene Profiles of the Desert 37

accumulates. For if OS be large, the rise of the fan surface will
be slow and the curvature of the bench will be flat; and if small,
the growth of the fan will be rapid and the curvature steeper. But
whether OS be large or small, it is the acceleration of the rate of
rise of the fan surface which determines whether the curvature shall
be convex or coneave upward. If the acceleration be negative, it is
convex; if positive, concave. And this acceleration is directly due,
as has been stated, to the ratios between the areas ORR,P and OSS,P
in two successive periods of equal time.

It is also evident that if the valley at one end of a uniform
mountain ridge be wide and at the other end narrow, the bench will
vary from flat to steep, the width of the bench remaining constant.
If, on the other hand, we have a mountain ridge low at one end and
high at the other, flanked by a uniformly wide valley, there will be
developed a flat bench at the low end of the range and a steep bench
at the high end; and similarly for other relations of mountain and
valley. :

In the ordinary ease, where the surface of the alluvial embankment
rises by diminishing increments and the surface of the suballuvial
bench is consequently convex upward, an interesting condition de-
velops in the late stages of the general process. In cross-section the
direction of the embankment slope is asymptotic to the hyperbolic
profile of the bench. In the late stages of the recession of the sub-
aerial front, when its height is relatively small, and the embankment
is relatively broad, the latter rises very slowly by increments that
are nearly equal; and the hyperbola approaches very closely to a
straight line and to tangeney with the surface profile of the embank-
ment. The profiles of both the bench and the embankment, though
mathematically distinet, are then practically coincident. Under these
conditions the horizontal extension of the embankment does not keep
pace with the recession of the subaerial front. Between the upper
edge of the embankment and the base of the front there is evolved
a graded rock slope. The suballuvial bench becomes at this stage a
subaerial bench, across which the detritus from the vanishing front
is swept in times of cloud-burst, to be spread over the surface of the
embankment below. This emergence of the bench and its persistence
as a subaerial feature appears to be most characteristic of granite
ranges which disintegrate into fragments composed chiefly of the
individual mineral constituents, and therefore very uniform in size.
The phenomena are exemplified in the group of mountains in southern

38 University of Califorma Publications in Geology [ Vou. 9

California west of the Colorado River near the Needles, as illustrated
in the photographs,* plates 1 and 2. Here broad alluvial embank-
ments, from six to ten miles across, rise by a gentle slope to the
summits of the ranges, where there are residual rock crests, or ‘‘nub-
bins,”’ and stretches where the crest has entirely vanished as a pro-
tuberance above the general slope. Within a mile or more of the
summit one passes, without appreciable change of slope. from the
alluvial detritus of the embankment on to a bare rock surface extend-
to the nubbins of the crest. The upper limit of the alluvium is a
feather-edge.

It thus appears that, in addition to the rock terraces of desert
ranges due, as explained by Paige,’ to the stripping of suballuvial
benches of the alluvium which once mantled them, we have to reckon
with similar features, which may be evolved subaerially, and yet not
by any process of sheet flood erosion, but by the normal process of
recession of mountain fronts.

The Alluvial Embankment.—The mode of growth of the alluvial
embankment determines certain features of structure which may be
of service as criteria for distinguishing it from other types of deposits
in the formations of past ages, when it appears as an element in
problems of stratigraphy. The discrimination desired may usually
be readily made in the coarser portions of the embankment by a mere
inspection of the character of the constituent fragments. The charac-
teristics of fanglomerate have been briefly described in a former
paper’? and in good exposures there is little likelihood of it being
confounded with either a marine or a fluviatile conglomerate. The
finer deposits on the outer edge of the embankment and those of the
playa are, however, not so easily distinguished from delta deposits
either above or below sea-level, or from lacustrine deposits. It is
therefore desirable to point out in what respects the configuration and
internal structure of an embankment of the desert differs from other
sedimentary formations which are commonly met with in studies of
the earth’s crust.

Considered as a whole, the alluvial embankment of the desert is
elongated in a direction transverse to the movement of the material
which comes to it. It results from this that the grading of size of

8 These photographs and the descriptions of the conditions which they

illustrate were kindly supplied by Messrs. W. L. Moody and A. W. Lawson,
of the geological staff of the Southern Pacific Company.

9 Op. cit.
10 Univ. Calif. Publ., Bull. Dept. Geol., vol. 7, no. 15, 1913.

1915 ] Lawson: The Epigene Profiles of the Desert 39

its constituent material is transverse to its general elongation, the
tendency being for the coarser material to remain on one side and
the fine to be carried to the other, at any and every stage of its growth.
Owing to the fact that the embankment transgresses the wasting
mountain mass, the fan growing broader as it rises, the fine material
of a late stage of its growth may be, and usually is, directly above
the coarse material of an earlier stage, with a gradation between.
The reverse condition of coarse above fine never occurs except where
the embankment has been dislocated by a large fault, the scarp of
which would supply a local source of coarse material.

But from a formational or stratigraphic point of view the em-
bankment which flanks a wasting desert mountain ridge cannot be
considered alone. Nearly all such embankments have a twin or sym-
metrical relation to another embankment on the other side of the
valley, and the fill of the valley must be considered as a whole. From
this point of view the formation is a twinned embankment with
similar structure on both sides of its axis of symmetry. In the later
stages of its growth the central part, the playa, is composed of fine
silts and sands flanked on either side by arkose, the latter in turn
erading towards the sides into coarse fanglomerate. But as to the
distribution of the different grades of material in the early stages
of the growth of the twinned embankment in particular cases we can
speak only in a speculative way, because we rarely have information
as to the configuration of the country when it first came under the
sway of ariditv. We may, however, discuss to advantage an assumed
case for the purpose of clarifying our ideas as to the essential features
of the internal structure of the embankment, recognizing that the
results deduced will vary greatly with other assumptions as to the
initial condition.

We may suppose: (1) That a deep V-shaped valley evolved by
erosion under humid conditions is suddenly brought under conditions
of aridity; (2) that by crustal warping or by alluviation the valley
becomes an enclosed basin; and that (3) the rocks are homogeneous.
In the course of time, by the recession of the valley sides from ON
and ON’ to FM and F’M’ in figure 4, the suballuvial benches OF and
OF’ will be cut and the surface of the twinned embankment will rise
to FPF’. At this stage the profile of the valley and the adjacent
mountains will be that of the ordinary desert valley in the Great
Basin. I do not suggest that the broad alluviated valleys of the Great
Basin thus originated as valleys of erosion in a humid climate; but

40 University of California Publications in Geology [ VoL. 9

that they may have done so is clearly possible. This possibility is
not here introduced in a discussion of the origin of these valleys, but
to bring out the essential structure of the embankments which fill them,
whatever may have been their initial profile and mode of forma-
tion. Considering now the surface profile of the valley MFPF’M’
as typical of the present valley of the Great Basin, the materials
which form the surface of the embankment may be for convenience
classified into three grades, coarse, medium and fine. The point a
may be taken as the outer limit of the coarse material and b the outer
limit of the medium, and the fine would extend to the center of the
valley. Similarly at the suecessively preceding stages P,, P,, P;, Py,
the points a,, d., d,, @,, would represent the outer limits of the coarse
material at the respective stages. At stages P, and P,, however, the
coarse material would reach the center of the valley and would, there-
fore, not be sorted from the medium and fine detritus. Also at the

a eT — 7,

Figure 4.—If the typical desert valley MFPF’M’ were evolved from the
initial steep-sided valley NON’, there would be developed the twinned embank-
ment FOF’ resting on the cut benches FO and F’O and having two intersect-
ing systems of stratiform structure.

stage P,, b would be the outer limit of the medium-sized material and
the fine would go on to the center of the valley; but at stages P,, P,,
P,, P,, P,, the medium-sized material would extend to the middle of
the valley and would therefore not be sorted from the fine. The same
would be true of the twin embankment on the other side of the valley.
Considering now the embankment in ideal cross-section, it follows
from what has been said that the coarse detritus is confined to the
bottom of the embankment and that its upper limit is the curve
drawn through the points a,, a., d,, a,, but that in the central region
the coarse is mixed with medium and fine material. Similarly the
coarse material is throughout the embankment, from the center of
the valley to a, overlaid by medium-sized material the upper limit of
which is the curve drawn through b, b,; and above this in the central
or playa region is the fine detritus. Of course under actual conditions
the demareations indicated by the points a, a,, b, b,, ete., are grada-
tional, and the locus of the mean position of these points in plan is

1915] Lawson: The Epigene Profiles of the Desert 41

an irregularly sinuous or serrate line. Nevertheless the general fact
remains that under uniform unchanging conditions we have built
up a sedimentary formation, which, by its tripartite stratiform sub-
division into coarse, medium and fine material would, and usually
does, suggest to the student of stratigraphy rather abrupt changes
of general conditions, whereas the only change that has transpired is
the gradual recession of the subaerial front, the source of supply of
the detritus. From a petrographic point of view these three divisions
of the embankment may be referred to in ascending order as fan-
glomerate, arkose and silt. It is noteworthy that all three increase
regularly in thickness away from the source of the material. All three
present two kinds of stratification. One of these is a formational
stratification determined by the upper and lower limits of the fan-
glomerate, arkose and silt respectively ; the other is the stratification
of actual deposition, which is parallel to slope of the surface of the
embankment, and is flatter than the formational stratification, being
thus in contrast to ordinary false bedding, which is steeper than the
formational stratification. It is also noteworthy that a central or playa
deposit of silts well segregated from arkose can be developed, under
the assumed conditions, only at a comparatively late stage of the up-
building of the embankment. In earlier stages the silt of the central
region is mixed with arkose and at still earlier stages with both arkose
and fanglomerate.

If our initial valley be wide-bottomed instead of V-shaped there
may be ample space for sorting, so that coarse or even medium detritus
may not reach the middle of the valley at any stage of the upbuilding
of the twinned embankment and lacustral deposition is possible. A
similar situation may arise if the valley be a graben. Hence the
central region of the twinned embankment may vary in the character
of its materials and, therefore, in structure according to the initial
profile of the valley at the inception of fan building. But for the
portion of the embankment that rests upon the suballuvial bench on
both sides of the valley the distribution of material and the resulting
structure are in all cases in a general way the same. :

The transverse profile of the embankments actually observable in
the desert is as even and uniform as is indicated in the discussion of
the ideal case, except that a slight upward concavity may in some
instances be detected. In the longitudinal profile, or that parallel to
the range, there is, however, a systematic irregularity, due to what
may be described as a transverse fluting of the embankment.

42 University of California Publications in Geology [ VoL. 9

The contour of the subaerial front for the greater part of the
time of its recession is not in reality a straight, or even a gently
sinuous, line, but is actually indentate. At the indentations are cafions
or gullies and from these emerge the greater part of the detritus
which forms the embankment and which is distributed radially from
an apex in, or at the mouth of, every canon or gully. It results
from these conditions: (1) that the longitudinal profile and contour
of the general embankment are sinuous; (2) that the sinuosity is
most acute near the mountain and flattens out toward the valley;
(3) that the mean hmit of the coarse detritus is in plan a sharply
sinuous or serrate line and the mean limit of the medium detritus
a smoothly sinuous line; and (4) that in the depressions of the longi-
tudinal profile the angle of slope of the embankment is less than in
the median lnes of the indvidual fans, and the amount of water
available for transportation is less. Since the conditions referred to
persist throughout the greater part of the time of the accumulations
of the embankment, the internal structure of the latter is regularly
more complex than might be inferred from the discussion of the ideal
case. This complexity will manifest itself stratigraphically chiefly
in the alternate thickening and thinning of the fanglomerate and the
arkose in the elongation of these formations parallel to the range,
and in an appreciable longitudinal component of dip of the actual
depositional stratification in opposite directions on the two sides of
the axes of the individual fans. In the later stages of the general
process, when the subaerial front is relatively small, this complexity
will become less marked; but if the front be reduced to nothing in
one part of a range while in neighboring parts it is still a prominent
feature, the variation in thickness and in dip of the deposits of the
embankment will be again accentuated.

The Subaecrial Front.—In the discussion of the ideal case the sub-
aerial front is represented by implication as a mountain slope having
a straight contour. This is a conceivable case on the assumption of
perfect homogeneity of material and structure; but as a matter of
fact none of the mountains of the desert are perfectly homogeneous,
and all their subaerial fronts have a more or less indentate contour.
The indentation may be slight in the early stages of front recession,
is most pronounced in the middle stages and becomes less intricate
in the later stages. By supplying a larger surface to atmospheric
attack the development of gullies and canons accelerates the general
process of recession, and in so far as the acceleration is local, it

1915] Lawson: The Epigene Profiles of the Desert 43

affects the configuration of the resulting suballuvial bench, in two
ways: (1) It favors the isolation of salients of the front as island-lke
rocky cones, which may be submerged by the rising of the alluvium,
or project above its ultimate surface and be reduced individually as
already described. (2) More regularly disposed inequalities of the
surface of the suballuvial bench may, however, result from the acute
indentation of the contour of the subaerial front. If we consider the
embankment as in large measure composed of an aggregate of fans
apexing in the re-entrants of the front, then it is apparent that the
eutting of the suballuvial bench proceeds in the direction of the
median line of every fan at a higher level than it does along the
interfan lines on either side. The result of this is that in longitudinal
section the beneh will be broadly undulating, just as the profile of
the surface of the embankment is. Moreover, since the excess of
elevation of the fan areas over the interfan areas means that for ¢
considerable period the surface of the embankment rises more rapidly
in the former than in the latter, the slope of the bench in the median
line of the fans will be somewhat steeper than in the line of the
interfan depressions.

The conditions which determine the indentate character of the
receding front and so cause these irregularities in the suballuvial bench
may be in some cases mere accidents of initial configuration, but they
inhere chiefly in the heterogeneity of the mountain mass. Some of
the rocks of which it is composed are more susceptible of degradation
than others and so recede at a more rapid rate. But rocks which are
least susceptible of degradation in a humid climate may be most
easily degraded in the desert. The most easily eroded rocks under
humidity are those which pass most rapidly into soil by chemical
decay; whereas in the desert the most rapidly receding fronts are
composed of rocks most prone to mechanical disintegration. Thus,
of two common types, quartzite and greenstone, the latter in a humid
climate may be easily decomposed to a pulverulent soil while the
quartzite, being little affected by bacterial action, is less rapidly eroded,
and forms eventually the residual ridges. In the desert, on the
contrary, the greenstone, being tougher, is not so readily disintegrated
as the highly elastic quartzite and the latter, therefore, recedes more
rapidly. It thus happens that the re-entrants of a subaerial front of a
desert range may be developed along belts of the harder rock and the
salients may be composed of softer, less elastic rock.

44 University of California Publications in Geology [ VoL. 9

The Ultimate Stage.
penultimate rather than an ultimate stage of geomorphic development

The peneplain is, as the term implies, a

under persistence of uniform conditions. The final stage is a plain; but
the term peneplain is conveniently used to cover both the penultimate
and the ultimate stages, since the latter is only rarely observed, or
inferred. Similarly the panfan is a penultimate stage in the reduction
of the relef of the desert under conditions of crustal stability. There
remains, therefore, the question of the ultimate stage and of the transi-
tion from the penultimate to the ultimate stage.

A desert reduced to the panfan stage may still be subject to cloud-
bursts, unless the smoothing out of the relef react upon the climate
and minimize still farther the precipitation. If such a reaction be
assumed, then we must recognize in the consequent increase of aridity
a tendeney which would make for preservation of the panfan stage.
If, however, the aridity be not intensified by the reduction of the
relief, then it seems probable that the forces which had hitherto been
engaged in building the embankment would become effective for its
modification. This modification would be manifest as a transfer of
finer material from higher to lower levels, which would build up the
playa at the expense of the fine and medium-sized material on the
middle slopes. The process would of course be in operation long before
the attainment of the panfan stage, particularly when cloud-bursts were
local to the fan slope and did not affect the subaerial front. But as
long as the latter continued to be a source of abundant detritus the
modifying tendency would be counteracted and masked by the normal
upbuilding process, except that it might appreciably contribute to a
shght upward coneavity in the fan profile. With the disappearance
of the subaerial front the cloud-bursts falling upon the fan surface
would be more effective for the transfer of material from higher to
lower levels, the running water being no longer charged with a load
from above the fan. This transfer would first accentuate the upward
concavity of the fan profile by (1) leaving the upper part of the
embankment relatively little affected, owing to the large size of the
fragments and the greater porosity in that region; (2) degrading
the middle slopes where the material is finer and less porous; and
(3) adding the transported material to the toe of the embankment
and to the playa. What the limits of this modifying process may be,
without the stimulus of crustal deformation, it is difficult to predict.
With increasing upward coneavity the position of the coarse detritus
on the upper margin of the embankment would become less stable and,

1915 | Lawson: The Epigene Profiles of the Desert 45

given sufficient time, might be withdrawn from the erest and expose
the suballuvial bench. This would be the more probable if the
fragments of rock constituting the upper edge of the fan were subject
to still farther reduction of size by mechanical disintegration. In
some kinds of rock of a coarsely erystalline texture, such as granite,
and particularly porphyritic granite, this reduction of the size of
fragments appears to occur regularly, while in other more homogene-
ous rocks the fragments appear to be able to withstand differential
dilatation and contraction without rupture after they have reached
a certain size. For granitic rocks, therefore, we might expect a strip-
ping of the suballuvial beneh at the crest. The latter would then
become subject to renewed disintegration, and some of the new detritus
would be transported down the slope; but eventually the angle would
become so low that the detritus would remain as a permanent mantle
protecting the underlying rock from further waste. The limit of
degradation of the middle slopes of the fan would be reached when
the line of demarkation between the freely permeable and the relatively
impervious detritus had migrated down the slope nearly to the level
of the playa.

Transmitted August 14, 1915,

EXPLANATION OF PLATE 1

Looking North along Manchester Divide, near Needles, California. Showing
alluvial embankment extending up to base of ‘‘nubbins’’ or residual crest of
mountain range. An approximation of the panfan stage of the desert cycle.
The subaerial front is small and the suballuvial bench and alluvial embankment
both large, the latter being from 8 to 10 miles in width.

[46]

UNIV. CALIF, PUBL, BULL. DEPT, GEOL. [LAWSON] VOL. 9, PL. |

Photo. W. L. Moody

.
a
; ,
t
ee
'

EXPLANATION OF PLATE 2

Looking south-east toward divide south of Sunrise Peak, 20 miles Southwest
of Needles. The upper feather-edge of the alluvial embankment fails to reach
the base of the subaerial front, and a bare even rock platform one to two miles
wide, having the same angle of declivity as the embankment, extends out from
the ‘‘nubbins’’ at the summit. Beyond this the slope has a width of from
6 to 8 miles to the base of the alluvial embankment.

UNIV. "CALIF. PUBL. BULL, DEPT. GEOL. [LAWSON] VOL. 9, PL. 2

Photo. W. L. Moody

es as 3 |
ycific Coast Region, by John GC. 3

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te

1. New Species of the
inces of North .

2. The Occurrence of O
Bruce L. Clark a

r

p. 49-58, 12 text figu

i

HORSES FROM THE MIOCENE AND
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By, eee

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 4, pp. 49-58, 12 text figures Issued November 22, 1915

NEW HORSES FROM THE MIOCENE AND
PLIOCENE OF CALIFORNIA

BY
JOHN C. MERRIAM

CONTENTS

PAGE
UTERO TEV ICO Ap RR ma Ra ep en ee 49
Nileray CHAP US SUNNATMS Tey S 1) sees ca ceccsebes = dese ep san sect oee 2. 0eeeedecass Pose, essabecaaceeaesuiadecce saccesecee 49
IMienychip pus amtermiomGamus sy m, Sp). 22sec cece tec ee ce cneenec cee see nee eee aca neceeen ne mence seer ceeneeerees 50
TO UO MMP PUSHECIOMENSIS; My S]s) cc..cecsectcc.cceececstcetee secs eae secleccSeeovecsse-czceucseceveeceeeesseseusiet 52
Hipparion mohavense callodonte, n. Var. -...2--.2-.2--c2:-c-0cce-ceeceeceeeceeeceeeeeeeeeeeeeeeeeeeeeee 54
TEU OD aR 0} ONBUSY ake of W al) Lapis gts (5) oye ee aes rer eee re nae 5d

Equus or Pliohippus, probably new

INTRODUCTION

In a study of the Tertiary mammalian faunas of California several
new species of protohippine horses have appeared. The designation
of these forms is desirable at this time in order that reference to the
species may be possible in publications which will appear in advance
of the papers including detailed descriptions of the new forms.

MERYCHIPPUS SUMANIT, n. sp.
Merychippus, near calamarius. Merriam, J. C., Univ. Calif. Publ. Bull.
Dept. Geol., vol. 6, p. 168, pl. 29, figs. la to le, 1911.

Type specimen, no. 21422. Barstow Upper Miocene, Mohave Desert, Cali-
fornia.

Upper cheek-teeth much smaller than in typical Merychippus calamarius or
in M. intermontanus. Crowns of cheek-teeth considerably elongated, markedly
curved, and well cemented; height of the crowns often equal approximately to
twice their width. Protocone round, tending toward circular form in cross-
section, and discrete up to a stage of very advanced wear. Enamel bordering
the fossettes commonly more complicated than in any of the larger Merychippus
forms of the Barstow Miocene. .

50 University of California Publications in Geology [ Vou. 9

This species includes the smallest members of the Merychippus
series in the Barstow Miocene. It is closely related to Merychippus
calamarius, and may possibly represent merely a variety of that
group. In the characters of the cheek-teeth this species approaches
Hipparion, from which it is distinguished by the more strongly curved
crowns of the upper teeth, and by the greater simplicity of the enamel
borders of the cement lakes. The cement covering of the cheek-teeth
is commonly thinner than in Hipparion, and there is no evidence of
functional cement on the milk molars.

Named in honor of John R. Suman who furnished the first specimen
of this species used in study of the Mohave Tertiary faunas.

MEASUREMENTS OF TYPE SPECIMEN, No. 21422

Length, anterior side M' to posterior side M?® ............ 57 mm.
P*, anteroposterior diameter --2.-2.-2c.- eteeeeeeeeeecceteses 22%
Pe ntramsvierse diameter ees. seeeee eee arene arene (EG
Pe pero it (Ob 1Or 0 wn yctee cect eae e eee ere eae eee eee 31.3
M’, anteroposterior diameter ...........22..22:.-::-:-e-e-seeeeeee ale):
Me. tramnsverseldianvetger cscs eres re eee 19.4
UY Erpgt Nave bttead eh re ME Cnt oy a), eee ee es hoe
MF; anteroposterior diameters sce... -ceeesens coerce 20.8
Me, transverse Cuameten cccsccessecrscsee. sateen se sees tee ee 18.1
Mie Ine tio late Ost, Cr Osyylg esc eeesee ee coe cee ee eres nee 32.8
M*, anteroposterior diameter .. . 19.7
Me tramsvierse diameter sesso eee 15.5
DES OD aN ca fost alee ONE CCR RO) NOt Vee eee eee renee ere reer rrne ree rere ere 32.6

MERYCHIPPUS INTERMONTANUS, n. sp.

Type specimen, no, 21400. An upper cheek-tooth dentition from locality
1401 in the Barstow Miocene of the Mohave Desert, California.

Cheek-teeth large; crowns long, strongly curved, heavily cemented. Proto-
cone of upper cheek-teeth uniting early with protoconule. Enamel walls border-
ing the fossettes comparatively simple.

This form includes the largest members of the Merychippus type
in the Barstow Upper Miocene of the Mohave Desert. It is dis-
tinguished from the typical Merychippus calamarius by its larger size,
longer crowns, heavier cementation, and more pronounced tendency
to union of the protocone and protoconule even in young individuals.
The species more closely approaches the Protohippus type than does
typical WM. calamarius, and might by some authors be included within
the limits of that Genus. It is here referred to Merychippus rather
than to Protohippus, as the milk dentition of a number of specimens
presumably representing this type seems to show less cement on the
crowns of the cheek-teeth than in typical Protohippus

New Horses from the Miocene and Pliocene

Merriam

1915]

Fig. 1. Merychippus sumani, n. sp. Type specimen, no. 21422, superior cheek-teeth, occlusal view, natural size. From the Barstow
Upper Miocene, Mohave Desert, California.
Figs. 2 and 3. Merychippus intermontanus, n. sp. Type specimen, no. 21400, natural size. From the Barstow Upper Miocene,

Mohave Desert, California.

Fig.

5)

St)

superior cheek-tooth series, occlusal view; fig. 3, M2, outer view.

52 University of California Publications in Geology [Vou. 9

MEASUREMENTS OF TYPE SPECIMEN, No. 21400

Length, anterior side P* to posterior side M? ........ 146 mm.
Length, anterior side P’ to posterior side P* ........ 78.8
Length, anterior side M* to posterior side M® ...... 67.
P?, anteroposterior diameter ...............2..22.:220-0000- 29.8
IP] transverse GUanet er see eeseeres essere oan: eres 18.5
P*, anteroposterior diameter . 24.5
P*, transverse diameter _.........00.0000000ceeee eee cece PPT
P*, height of somewhat worn crown .................-.-.- 44.

ia
to

p*, anteroposterior diameter -_.....-.-..2..2.-2-cceccseccoseenee

H

Ps, ‘transverse Giameter® 22-:..2c:2:--sece-2-2e2e eevee eeeeeoeeece

M’, anteroposterior diameter ............2..22.22.:2::210---
M’, anteroposterior diameter ...............----:--:01--00-----

i

M?, transverse diameter .........--...-----::----:cc--eeeeeeeeee0* ;
Hit Epa a= oy aT (0 a On iC Atk eee ns ee eee ener ere 3.

a
bo

M*, anteroposterior diameter .
Mis’ transverse uameter <..c.c-accn-ce-- nner sees eens

Ke wp £& WD Wl Ww bW bo
ea .
Es |

Q
ve

a, approximate.

PROTOHIPPUS TEHONENSIS, n. sp.

Type specimen an upper molar, no. 21779, from the Tejon Hills, southern
end of San Joaquin Valley, California.

Upper molar crown strongly curved and well cemented; outer styles of
moderate strength; protocone considerably flattened transversely and connected
with the protoconule by a wide isthmus; fossettes wide transversely and show-
ing plication of enamel only on the adjacent borders.

Figs. 4a to 4c. Protohippus tehonensis, n.sp. M’*?, type specimen, no. 21779,
from the Tejon Hills, southern end of the San Joaquin Valley, California. Fig.
4a, occlusal view; fig. 4b, outer view; fig. 4c, posterior view.

53

New Horses from the Miocene and Pliocene

Merriam:

1915]

Figs. 5 to 7. Hipparion mohavense callodonte, n.
Ricardo Postoffice, Mohave Desert, California. Fig.
teeth, occlusal view.

var. Cheek-tooth series, no. 21311, natural size. From the Ricardo Pliocene, near
5, superior cheek-tooth, occlusal view; fig. 6, M*, outer view; fig. 7, inferior cheek-

on
TS

University of California Publications in Geology [ VoL. 9

The West-American forms nearest P. tehonensis are a rare Proto-
hippus or Pliohippus represented by no. 21423 from the Barstow
Upper Miocene, and a form referred to Pliohippus oceurrig in the
lower portion of the Jacalitos Pliocene of the North Coalinga region.
The Barstow species is near P. tehonensis in form and dimensions,
but differs shightly in form of the protocone, strength of the enamel,
and possibly in degree of cementation of the crowns. It seems to the
writer doubtful whether the Barstow and Tejon Hills forms are
specifically identical. The North Coalinga species described by Arnold
and Anderson! from the Jacalitos formation, and determined as Plio-
hippus, approaches P. tehonensis very closely and may be specifically
identical. As yet we have only three teeth from the Jacalitos and all
represent M*, so that a fully satisfactory comparison cannot be made.

Pliohippus tantalus of the Ricardo Pliocene is larger and heavier
than the Tejon Hills species, its fossettes are larger and differently
formed. A Pliohippus species from Ricardo near P. mirabilis re-
sembles the Tejon Hills species in dimensions, but seems to differ in
details of form of fossettes and is presumably not of the same species.

MEASUREMENTS OF TYPE SPECIMEN, No. 21779

2M’, anteroposterior diameter ........-....-..----.-c:--------02 22.5 mm.
ME, transverse diameter <2.22c2c20cccececeeccee-cesseeeeaes oes 23.7
?M', anteroposterior diameter of protocone ............ a 84

a, approximate.

HIPPARION MOHAVENSE CALLODONTE, n. var.

Type specimen, no. 21311, a finely preserved dentition including the upper
and lower cheek-teeth with several of the incisors. Collected in the Ricardo
Pliocene near Ricardo Postoffice, on the western border of the Mohave Desert,
by Emerson M. Butterworth.

In this form the dentition differs noticeably from that of the
typical Hipparion mohavense of the Ricardo Pliocene. The protocone
is more strongly flattened transversely, while the enamel pattern of the
teeth in general shows fewer deep, smoothly-rounded folds. The
plications of the enamel in this form tend to be more distinctly
angular, and there are more numerous minute folds. The dimensions
differ somewhat from those of the typical H. mohavense. The differ-
ences in dimensions and in pattern of the cheek-teeth separating this
variety from typical H. mohavense may be due in some part to varia-
tion in stage of wear, but the characters seem sufficiently marked to

1 Arnold, R., and Anderson, R., Bull. U. 8. Geol. Survey, no. 398, p. 98, 1910.

=

1915] = Merriam: New Horses from the Miocene and Pliocene 55

require at least tentative recognition in the classification. It is pos-
sible that fuller collections may ultimately show an intergradation
between this form and H. mohavense.

MEASUREMENTS OF No. 21311

P?, anteroposterior diameter 29.9mm. P., anteroposterior diameter .... 28.4 mm.
P*, transverse diameter _.... 20.2 P., greatest transverse diameter 12.
P*, anteroposterior diameter 27.4 P,, anteroposterior diameter .... 27.
P*, transverse diameter ...... 23.2 P;, greatest transverse diameter 13.7
P*, anteroposterior diameter 24.8 P,, anteroposterior diameter .... 27.4
P*, transverse diameter ...... 21.5 Py, greatest transverse diameter 13.
P*, height of mesostyle ...... 45.5 P,, height of protoconid .......... 51.
M’, anteroposterior diameter 24.5 M,, anteroposterior diameter.... 25.8
M’, transverse diameter -..... 22.6 M,, greatest transverse diameter 11.4
M’, anteroposterior diameter 24. M., anteroposterior diameter... 27.3
M?, transverse diameter ...... 20.4 M., greatest transverse diameter 10.8
M’, height of mesostyle ...... 41. M,, height of protoconid -........... 44.4
M*, anteroposterior diameter 21. M;, anteroposterior diameter.... 25.
M°, transverse diameter ...... 18. M;, greatest transverse diameter 10.4

PLIOHIPPUS FATRBANKSI, n. sp.
Type specimen, a large unworn upper cheek-tooth P*?, no. 19789, from the
Ricardo Pliocene, near Ricardo Postoffice, California.
The type specimen of P. fairbanksi represents a protohippine form differing
considerably from Pliohippus tantalus of the Rieardo Pliocene. The crown is a
little more strongly curved and the styles are heavier. The fossettes are nar-

Figs. 8a to 8c. Pliohippus fairbanksi, n. sp. P*?, type specimen, no. 19789,
natural size. From the Ricardo Pliocene near Ricardo Postoffice, Mohave Desert,
California. Fig. 8a, occlusal view; fig. 8b, section at base of upper third of
crown; fig. 8c, posterior view.

56 University of California Publications in Geology [ Vou. 9

rower and have a distinctly different form. The protocone is small and round.
In this particular specimen the protoloph and metaloph remain separate almost
to the base of the tooth.

The nearest approach to the form seen in specimen no. 19789 is
that in a tooth type (no. 21341) from the Etchegoin Pliocene of the
North Coalinga region of California, on the western border of the
San Joaquin Valley. The Etchegoin form shows rather narrow fos-
settes, a very small, round protocone, and a weak connection of
protoloph and metaloph. The cheek-teeth of the Etchegoin species are
considerably narrower and less curved than the Ricardo form, and
appear to be specifically different.

This species is named in honor of Dr. H. W. Fairbanks, who was
one of the earliest investigators to study the Ricardo Pliocene beds.

MEASUREMENTS OF TYPE SPECIMEN, No. 19789

P*, height of crown on outer Side ...........2..22.-22020-00--++ 55 mm.
p* anteroposterior diameter -.....2.2.c¢cccececcceseecsceeceeeseenem) OD
IPs transverse diameter 2... sc.sesseoecetee ss sees see ee cens eee 26.4

EQUUS or PLIOHIPPUS, probably new
Equus or Pliohippus, sp. Merriam. Amer. Phil. Soc. Trans., u.s., vol.. 22,
pt. 3, p. 223, 1915.

Upper and lower cheek-teeth, from beds in the upper portion of the Etche-
goin formation north of Coalinga.

Cheek-teeth large, long-crowned, heavily cemented. Upper cheek-teeth with
heavy mesostyle, fossettes wide with moderately crinkled enamel borders. Pro-
tocone large, strongly compressed laterally, inner border convex. Metaconid-
metastylid column of lower cheek-teeth often with wide inner groove.

Of the described species this form most closely approaches Equus
or Pliohippus simplicidens of the Blanco Pliocene. It possibly differs
from Equus simplicidens in somewhat greater width of the fos-
settes of the upper cheek-teeth and in the greater anteroposterior
diameter of the protocone. The form of the protocone is not fully
shown on Cope’s figure of the type specimen of E. simplicidens, but
this pillar is restored by Cope and Gidley as relatively shorter
than in the Coalinga species. According to Gidley the teeth of E.
simplicidens have the appearance of being comparatively —short-
crowned. The lower teeth referred to E. simplicidens are char-
acterized by the angular nature of the groove on the inner side of the
metaconid-metastylid column. In a specimen, no. 21333, from North
Coalinga this groove is rather sharply angular. In specimen no, 21332
the groove is wider and approaches the form seen in Equus.

1915] Merriam: New Horses from the Miocene and Pliocene 57

Fiala
x.
ze9 Sys

HH HALD HCH ngnrDl DRA in uinaer RL stegcs oo

12b

Figs. 9a and 9b. Hquus or Pliohippus, sp. M’, no. 21330, natural size. From
upper Etchegoin beds, North Coalinga region, California. Fig. 9a, occlusal view;
fig. 9b, inner view.

Figs. 10a and 10b. Hquus or Pliohippus, sp. P*?, no. 21331, natural size. From
upper Etchegoin beds, North Coalinga region, California. Fig. 100, occlusal
view; fig. 10b, outer view.

Fig. 11. EHquus or Pliohippus, sp. Ms, occlusal view. No. 21333, natural size.
From upper Etchegoin beds, North Coalinga region, California.

Equus or Pliohippus, sp. P.?, no. 21332, natural size. From

Figs. 12a and 12b.
12a, occlusal

upper Etchegoin beds, North Coalinga region, California. Fig.
view; fig. 12b, inner view.

58 University of Califorima Publications in Geology [ Vou. 9

The occurrence of this species in the upper portion of the Etchegoin
formation shows the existence of a relatively advanced type of horse
in the California region, at a time near middle Pliocene.

As nearly as can be determined from the fragmentary material
available this species is intermediate between advanced Plohippus-
hike forms and Equus. The internal wall of the protocone is convex,
instead of concave, as normally the case in Equus, but the anterior
end of the protocone is searcely extended anteriorly beyond the isthmus
uniting protocone with protoconule. If the characters of this form
are satisfactorily represented in the specimens at hand, and only one
form is represented, the species would seem to furnish a transition
between Equus and Pliohippus.

No name is given to this form at present as more and _ better
material is desired before final estimation of the characters is made.

Transmitted October 23, 1915.

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of ertiary Echinoids from the San Pablo Group of Middle California, by William S.
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. ass, near Pyramid Lake, Nevada, by John CO. Merriam ............-c-c-c-cecececeeeseeeseeeeeeeees 10e
Fauna of the San Pablo Group of Middle agai a by Bruce L. Clark.............. 1.75

Index i in press,

2. The Occurrence of Oligoce: @ in the Con
q Brice L. Clark ....... :

+ 3. The Ipigene Profiles o hee

a orses from the Miocene and Pliocene of |

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ol. 9, No. 5, pp. 59-76, plates 3-6 ; Issued January 20, 1916

t

CORALS FROM THE CRETACEOUS AND
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AND OREGON

1

BY

oe . JORGEN O. NOMLAND

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VOLUME 7.

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 5, pp. 59-76, plates 3-6 Issued January 20, 1916

CORALS FROM THE CRETACEOUS AND
TERTIARY OF CALIFORNIA
AND OREGON

BY

JORGEN 0. NOMLAND .
CONTENTS

PAGE

Pini GG GL omy 2 2s cs seek eee nace ceca sete su cc pueden tas eines See even at Se Dose dy opteveeedte Neceeuy iv Geb. ceeveudeee¥ase 59
ID ESCTUP TION GOL SP CCLOS oa escapee sen 5o os se ec anata ceed cee Sec cht cac vue tagcat sbeensctbeccunbesceenazereetnecenecs 61
Murino amdickerSON, sMeiSp. ccescese oes ces setsesee se eeeeecevacstvcascevcevescSveseeqses fepbussecscz saree 61
Munbimolia Muswllanima, NSP. seececcececcccqcececceecee seceececeecocesncecenceeceaseenceceeeeseeeeadeszeee- 62
alo elma?) Merriam We Sp: fesse snes secu ccvs cee cseceesvevecescsgsdesseceicout sdoved-cudeeeets erate 62
MrochocyabhustiMpPerialiSs MW. Spe seecccecceececceescseveseeceeceecceeseceencaoscceeceseecaeeedereue-cecaes 63
no choca bus ORCMOMeNSIS,) Me .SP eqs. cscecc cesta eesetencceseee esc e eee een ee eee cee eee 63
Mrochocyathusspergranulatus, | Me Sp. cce-ccccecescecceeccececccceceseceqeeccceseae-ecgeeeecczeeeeesea: 64
BN EAYCG Betl oe ees eo K oy BCG Ue aes Ts) egg a ge 64
PATS UT ANIOUA eT STOMA AC Ay SN) aS ]) syrsee.vseeetes sods fees aes Paeese ates sete godess fesae eSetcasgoteeese vScnea0sasice 65
idlenasbrean class Nets see: tet ceeter=2.-coc. leseseeesess ste veoeessevssiiecsaesesstoni elses ees 65
Balamoyo hiya aie vii allo WSS ae Sy) ve cess cecte weuncaseen asses eee scence vaece sean -ea sess es eeeeeeeeeee-cee 66
Stephano phy tlie sCallatOrmMlC ay mS]. y see ceeseeeceee coe ccseececescescesnees=2¥eeseceveeseee ees es 66
Mendmophiylilahammy aay Me SPs. seseesceeee se ceeeeees sees eeeveseeeeeeceeeesent oe 2.2 cc eheceesec 67
Mendrophiyllia tejOMensis, We /Spe se cee ese cske sees ccs cee ceeseeeeceersctencesecceecseceseeeseueesess 67
Mamma sGeriay SIMU ata. iS sy cece: seeceee sce ce ze -eFeceeceeee sess ee cceeesec eee oeeseeeeee sees sae sees ee 68
(Cio aay Oya HREED NUM ORT gL 1h SY OY ee geen Pe ee 68
(Gy caT TST SIE oR eee ener SR ate nec ee 69
Prochocyathus zitteli Merriam) -22_-.-..-.-ccccceccccceccecnseesensnceeeeenenseesenceneeseeeteaseuer sacs 69

INTRODUCTION

Although several species of corals have been described from the
Pacific Coast Cretaceous and Tertiary, the members of this group have
been used only to a limited extent for correlation purposes. The
present paper is an attempt to present a discussion of the Pacific
Coast corals in such form that this group may be of larger use to the
palaeontologist and to the stratigraphic geologist. A number of new
species of West Coast corals available to the writer in various collec-
tions are here described.

60 University of California Publications in Geology [VoL. 9

TABLE SHOWING STRATIGRAPHIC POSITION OF PACIFIC COAST CORALS

Horizons

Lower Middle Upper

Caryophyllia arnoldi Vaughan? .............. x x x
PLEISTOCENE Caryophyllia pedroensis Vaughan? ........ x x x
Paracyathus pedroensis Vaughan? ........ x x x
Astrangia coalingensis Vaughan’ .......... a x
Astrangia insignifica, n. Sp. 2.2.22... ae ns x
Caryophyllia californica Vaughanté ...... ze ee x
ae Favia merriami Vaughan? ......22.2..2...--- — x
Madripora solida, n. Sp. ---.......--22.-22---------- a x
Stephanocoenia fairbanksi Vaughan?.... .... x
Stephanocoenia fairbanksi var. colum-
MATIS) Vial ph ans eee eset secerereeees-s Bee x
MI0CENE No described species.
(iGGGaan eee hannibali, n. sp. .............- aes x
ae Clambkay jms Sy. eeeees-c-csceee eet --eece des x
Balanophyllia variabilis, n. sp. ...........--- pan ae x
Dendrophyllia tejonensis, n. sp. ...........--- a x
Flabellum californicum Vaughan3 ........ nee = x
Flabellum(?) merriami, n. sp. ....-.......---- x
Flabellum remondianum Gabb1, 3, 7........ q
f Goniopora vaughani, n. Sp. -...---..:-2-0e----- ar x
Stephanophyllia californica, n. sp x x x
TEJON Thamnasteria sinuata, n. sp. .........2222---- x iS
Trochocyathus californica Vaughan...... x
Trochocyathus(?) perrini Dickersoné.... x
Trochocyathus stantoni Vaughan? ........ : x
Eocene ~ Trochocyathus striatus (Gabb)1) 3_......... = ? x
Trochocyathus imperialis, n. sp. ............ x
Turbinolia dickersoni, n. sp. ............------- x x x
Turbinolia pusillanima, n. sp...............--- x
Flabellum remondianum Gabbt1, 3, 7........ x x x
MarTINEZ) Smilotrochus(?) curtis Gabb? ................ x pass
Trochocyathus zitteli Merriam, 7.......... x x x
Haimesiastraea petrosa (Gabb)1, 3........ ? ? ?
; Trochosmilia(?) granulifera Gabbt........ x
ene Trochocyathus oregonensis, n. sp. ........-. x
Trochocyathus pergranulatus, n. sp....... x

1Gabb, W. M., Geol. Surv. Calif., Palaeontology, vol. 1, 1864.

2Gabb, W. M., Geol. Surv. Calif., Palaeontology, vol. 2, 1869.

3 Vaughan, T. W., U. S. Geol. Surv., Monograph 39, 1900.

4 Arnold, Ralph, Calif. Acad. Sci., Memoirs, vol. 3, 1903.

5 Arnold, Ralph, U.S. Geol. Surv., Bulletin 396, 1909.

6 Dickerson, R. E., Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, no. 12, 1913.
7 Dickerson, R. E., Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, no. 6, 1914.

1916] Nomland: Corals from Cretaceous and Tertiary of Califorma 61

The writer is indebted for criticism and advice to Professor J.
C. Merriam, who a number of years ago made an extensive study of
California corals and first used them for correlating purposes in the
Martinez. Acknowledgment is due to Dr. R. E. Dickerson, whose
extensive studies in the California Eocene have made a large part of
this work possible.

The writer wishes especially to express his gratitude to Dr. T.
Wayland Vaughan of the United States Geological Survey for
examination of the manuscript and criticism of the palaeontological
determinations.

DESCRIPTION OF SPECIES

TURBINOLIA DICKERSONT, n. sp.
Plate 3, figures 5, 6, 7, 8
Type, University of California Department of Palaeontology collections. The

type is from locality 1817, near center of sec. 15, T. 18 S, R. 13 E, M. D. B. & M.,
Fresno County, California.

Corallum conical. Costae 24, prominent, only six reaching the base,
of nearly the same thickness at thecal wall and margin, the twelve
longer costae appear but slightly widened near the base, margin flat-
tened. Intercostal furrows with double rows of pores, in some of the
larger specimens a low ridge appears between the rows on upper por-
tion. Septa corresponding in number to the costae, those of the
primary eycle slightly larger at the calicular margin. On lateral faces
of septa are numerous rows of granules extending from wall to septal
margin. The columella at the calice projects somewhat above the
margin of the septa and appears as a six-pointed star, the rays of
which are connected to the primary septa. Diameter of corallum,
2.8mm.; height, 6.7 mm.

Occurrence at University of California localities 692, 1817, Tejon
group, Eocene.

This species seems to resemble closely Turbinolia phareta Lea, as
described by Vaughan. 7. dickersoni appears to differ, however, in
having the costae of nearly the same thickness at the margin and
thecal wall, the costae are not so much widened near the base, and
the septa are not of uniform size at the peripheral portion of the
calice. Also in 7. dickersoni the rows of septal granules extend the
whole distance across the septa, although in some rows interrupted
about two-thirds of the distance from the wall.

62 University of Califorma Publications in Geology [ Vou. 9

TURBINOLIA PUSILLANIMA, n. sp.

Plate 3, figures 9, 10

Type from locality 476, in the University of California Department of
Palaeontology collections.

Corallum conical, slender. Of the forty-eight costae twenty-four
reach only one-third of distance to base, while twelve others seem to
disappear near the base. The costae are much narrower where the
forty-eight are present. Costal margin acute. Intercostal furrows
narrow, of less width than the costae. Pores present between the
costae. The twenty-four septa corresponding to the shortest costae
extend only a short distance from the wall. Diameter of corallum,
3.3 mm.; height, about 5.7 mm.

Occurrence at University of California localities 476, 1817, in the
lower Tejon group, Eocene.

Turbinolia pusillanima, n.sp., occurs at the type localities of both
Thamnastria sinuata, n.sp., and Flabellum(?) merriami, n.sp., with
the faunas listed under these species.

FLABELLUM(?) MERRIAMI, n. sp.
Plate 3, figures 1, 2, 3, 4. Plate 4, figure 17

Type from University of California Department of Palaeontology collections,
from locality 1817 on branch of Salt Creek, near center of sec. 15, T. 18 8,
R. 13 E., M. D. B. & M., about sixteen miles north of Coalinga, Fresno County,
California.

Corallum cuneate near the base, but above compressed zone around
corallum near the middle a transverse section is elliptical. Angles
at end of longer transverse axis are acute near the base. The twelve
well-defined costae have between them thirty-six others of less promi-
nence, which apparently almost disappear before reaching the basal
portion. The costae which correspond in number to all the septa are
broad and covered with large granules. Intercostal grooves narrow.
Septa occur in four cycles, the septa of the third cycle apparently
fused to the second; septal faces granular. A true columella seems to
be present. Greater transverse diameter, 5.2 mm.; lesser transverse
diameter, 4.5 mm.; height of corallum, 4.6 mm.

Occurrence at University of California locality 1817, lower Tejon
group, Eocene.

1916] Nomland: Corals from Cretaceous and Tertiary of Californa 63

This species occurs at the type locality with the following char-
acteristic Tejon species: Trochocyathus imperialis, n.sp., Turbinolia
dickersoni, n.sp., Turbinolia pusillanima, n.sp., Cancellaria stantoni
Dickerson, Conus hornii Gabb, Ficopsis remondi Gabb, Rimella simplex
Gabb, Terebra californica Gabb, Turritella andersoni Dickerson, Turris
fresnoensis Arnold, Venericardia planicosta hornw (Gabb).

TROCHOCYATHUS IMPERIALIS, n. sp.
Plate 4, figures 11, 12

Type from University of California Department of Palaeontology collections
from locality 1817.

Corallum short, cornute, basal part small and curved in the direc-
tion of the lesser transverse diameter. Section cut transversely to
longitudinal axis has elliptical outhne. Small sear of attachment
shown at base. Costae about sixty-four, granular, twelve show stronger
development. Between the more prominent costae are three to five of
less prominent development, becoming more numerous around upper
portion of corallum. In transverse section cut about two-fifths from
base, most of the septa of the first three cycles reach the columella.
Fourth cycle complete. Pali present inside of first three cycles.
Synapticulae which appear to be incomplete present. Columella
fasicular. The measurements of the type were as follows: height of
corallum, 19.8 mm.; greater transverse diameter, 14.6 mm.; lesser
transverse diameter, 13.1 mm.

Occurrence at University of California localities 1817, 1412.

At the type locality this species occurs with Flabellum(?) mer-
riam, n. sp., and its associated fauna.

TROCHOCYATHUS OREGONENSIS, n. sp.
Plate 4, figures 9, 10

Type from Forty-nine Mine, Jackson County, Oregon.

Corallum elongate, slightly curved in direction of the lesser trans-
verse axis. Transverse section circular to subcircular. Costae forty-
eight, rather prominent, granular, rounded, of the same size. Septa
corresponding in number to the costae, rather thick, in four eyeles of
which only the first reaches the columella. Pali well developed, before
the first three cycles of septa. Columella strong, fasicular. Greater
transverse diameter of corallum, 8 mm.; lesser transverse diameter,
7.7mm.; height, 29 mm.

Occurrence at Forty-nine Mine, Jackson County, Oregon. Accord-
ing to F. M. Anderson, the fauna from this locality is lower Chico.

64 University of California Publications in Geology [ Vou. 9

TROCHOCYATHUS PERGRANULATUS, n. sp.
Plate 3, figures 16, 17

Type from locality 484, SE 4 of SW % sec. 9, T.1 8, R.1 E, M. D. B. & M.,
in University of California Department of Palaeontology collections.

Corallum apparently conical. Transverse section elliptical. Costae
forty-eight, granular, rounded, of not very prominent development.
Between the costae are an equal number of rows of small granules
which do not appear to have corresponding septa. The forty-eight
septa are arranged in four complete cycles of six systems. Septal
faces granulated. Pali bilobate, granular, before the first three cycles
of septa. Columella almost rudimentary, consisting of only very few
trabiculae. Greater transverse diameter, 6.7 mm.; lesser transverse
diameter, 5.4 mm.; height of corallam perhaps about 14 mm.

Occurrence at University of California locality 484 in the Chico,
Cretaceous, on the south side of Mount Diablo, Contra Costa County,
California.

MADRIPORA SOLIDA, n. sp.
Plate 5, figures 1, 2

Type in University of California Department of Palaeontology collections
from locality 738.

Corallum seeming to branch irregularly. Cross-section of corallites
elliptical. Costae distinct, broad, slightly granulate, corresponding in
number to the septa. Septa thick, variable in number, lateral faces
apparently smooth, the inner edges of the first and second cycles may
be fused to others in an asymmetrical arrangement. Columella
absent. In the type specimen the corallites vary considerably in size.
The cross-section of the smallest but most perfect corallites shown in
the figure had the following dimensions: greater diameter, 8 mm.;
lesser diameter, 6.5 mm.

Occurrence near the base of the Carrizo formation, Pliocene, from
University of California locality 738 on the south side of Coyote
Mountain, San Diego County, California.

Three other species of corals from this locality have been named
in manuscript by T. W. Vaughan and listed by Ralph Arnold in United
States Geological Survey Professional Paper 47. Material in the
University of California collections generically the same as given in
unpublished manuscript by Vaughan from the same locality is there-
fore not described in the present paper.

1916] Nomland: Corals from Cretaceous and Tertiary of California 65

ASTRANGIA INSIGNIFICA, n. sp.
Plate 3, figures 14, 15

Type in University of California Department of Palaeontology collections,
trom corner Fourth and Broadway streets, Los Angeles, California.

The material at hand consists of a single corroded specimen ot
slightly elliptical outhne. It appears to have been connected to other
eorallites by a thin basal expansion. No costae are visible; this may
perhaps be due to the worn condition of the specimen. Calice shallow.
Septa in four cycles, thick, granulate, those of the third cycle fused
to the second; the septa of the fourth cycle very small. Columella
well developed, vesicular. Altitude of corallite, 2 mm.; maximum
latitude, 8.3 mm.

Occurrence in upper Fernando formation, Phocene, at corner of
Fourth and Broadway streets, Los Angeles, California, in material
donated to the University of California by J. Z. Gilbert.

SIDERASTREA CLARKI, n. sp.
Plate 5, figures 3, 4

Type from locality 1131, one-half mile SSW of the town of Walnut Creek,
Contra Costa County, California. In University of California collections, De-
partment of Palaeontology.

Corallum massive, subrounded. Corallites angular, mostly pentag-
onal, separated by a prominent wall which is strengthened inside by
numerous adjoining synapticula. Septa about forty-eight, margins
apparently dentate, beginning with the third each succeeding cycle is
fused to the one that precedes it. Interseptal synapticula present and
are especially well developed in a grouping around the inside of the
wall, giving this the appearance of being very heavy. <A well-developed
columella present. Diameter of calices about 7.7 mm.

Occurrence near base of Agasoma gravidum zone, Oligocene, at
locahty 1131.

A large fauna has been collected at the type locality of this species,
among others the following characteristic Oligocene forms: Agasoma
gravidum (Gabb), Amiantis mathewsonu (Gabb), Ancillaria fishii
Gabb, Dosima mathewsoni Gabb, Dosima whitneyt (Gabb), Molopo-
phorus gabbi Dall, Molopophorus biplicatus Gabb, Mytilus mathew-
sonu Gabb, Priscofusus hecort Arnold.

66 University of California Publications in Geology [ Vou. 9

BALANOPHYLLIA VARIABILIS, n. sp.
Plate 4, figures 2, 3, 4, 13

Type from University of California Department of Palaeontology collections,
from locality 714, NE 4% of SE \& see. 21, T. 1 8, R. 1 E, M. D. B. & M.

Corallum variable in shape from elongate to short cornute, curved
in the direction of the lesser transverse axis. Cross-section elliptical
to subcircular. Wall strong, vesicles not numerous. Costae granular,
rather wide, rounded, with narrow intercostal grooves; on some speci-
mens a tendency is shown to have every fourth costa of more prominent
development. Septa in five cycles, lateral faces granulated, thin at
calice but becoming thicker as base is approached, third and fourth
cycles fused to the third. Columella somewhat fasicular, in some
sections cut near the calice, however, the columellar space seems to be
traversed largely by extensions of septa of the first three cycles.
Greater transverse diameter, 10.7 mm.; lesser transverse diameter,
10.3 mm.; height of corallum, perhaps about 45 mm., but exact height
unknown since in the material at hand no complete specimen of the
longer variety could be found.

Occurrence at University of California localities 507D, 714, 1853,
in the upper Tejon Eocene.

This species, on account of its slight superficial resemblance to
Trochocyathus striatus Gabb, has heretofore been identified as such
by California palaeontologists. Balanophyllia variabilis, n.sp., how-
ever, seems to occur more commonly in the Tejon group than T7.
striatus Gabb. In one of the old collections at the University of
California the two are from the same locality. It is not known to
what extent, however, this material can be relied upon.

STEPHANOPHYLLIA CALIFORNICA, n. sp.
Plate 3, figures 11, 12, 13

Type, University of California Department of Palaeontology collections,
from locality 716, on south side of Mount Diablo, Contra Costa County, Cali-
fornia.

Corallum simple, planoconvex lens-shaped. Base _ discoidal.
Costae ninety-six, of these the first three cycles reach the center, the
two last cycles fused to the ones preceding it. Mural pores well
defined. Calice convex, marked by a rather deep depression in the
center. Septa ninety-six; of these the primary and secondary reach

1916] Nomland: Corals from Cretaceous and Tertiary of Califorma 67

the columella; tertiary and quaternary are united to the first two
eyeles. The septa of the fifth cycle are free and very short. Calicular
margin and lateral faces of septa granulated. Columella weak.
Measurements of the type, which is a rather small specimen, were as
follows: Diameter, 7.8mm.; height of corallum, 2.7 mm.

Occurrence in the Tejon group at University of California locali-
ties 692, 716, 719, 734.

DENDROPHYLLIA HANNIBALI, n. sp.
Plate 6, figures 1, 2, 3

Type in palaeontological collections of Stanford University, from locality
NP15, near log dam, Porter Creek, Chehalis County, Washington.

Colony branching, forming several vertical series which unite when
coming in contact. Calices deep, nearly round, projecting only slightly
above surface, apparently arranged in nearly vertical series, about
5mm. in diameter. Costae distinct, vermicular, granulated, covering
the whole surface. Intercostal furrows narrow, perforate. Wall thick,
porous but rather dense. Septa about 42-48, thin and fragile near
ealice, granulated, in four cycles having arrangement characteristic of
the genus. Columella weak.

Occurrence at Stanford University locality NP15, middle Oligocene.

It is deemed advisable to incorporate a description of this species
in the present paper, although it properly does not belong to the
California province.

DENDROPHYLLIA TEJONENSIS, n. sp.
Plate 4, figures 1, 5

Type from University of California Department of Palaeontology collections,
from locality 458, on west side of Grapevine Creek, four and one-half miles
S 6° W of 1085 B.M., Tejon Quadrangle, California.

Corallum branched, transverse section of corallites elliptical. Costae
prominent, perforate, slightly granulate, arranged longitudinally.
Intercostal furrows rather wide and have numerous pores. Wall thick,
appears to be strengthened by synapticula arranged adjacent to it.
Septa numerous, thin, perforate, lateral faces granulate, arranged in
five cycles. Columella not very strong, open spongy. Greater trans-
verse diameter of corallite, 8.5 mm.; lesser transverse diameter, 6.4 mm.

Occurrence near middle of type Tejon section, from University of
California locality 458, Eocene.

68 University of Califorma Publications in Geology [ Vou. 9

In the type section of the Tejon group from which Dendrophyllia
tejonensis, n.sp., is described the following species, among others, have
been reported: Amauropsis alveata Gabb, Cardium brewer Gabb,
Ficopsis remondiw Gabb, Perrisolax blakei Gabb, Turritella wvasana
Conrad, Venericardia planicosta horn (Gabb).

THAMNASTERIA SINUATA, n. sp.
Plate 5, figures 5, 6

Type in University of California Department of Palaeontology collections,
from locality 476, SW 4% of NW \ sec. 22, T. 18, R.1 E, M. D. B. & M.

Superior portion of corallum flat, curving down at the margin.
Calices nearly round, well defined, very unequally distributed on the
calicular surface. Columella well developed. Septa twelve, prominent,
lamellar, between those are seen in thin section an equal number
not as prominent development. Septa-costae continuous with those
of the neighboring calices, show a decided tendency to parallel arrange-
ment. Synapticula appear to be present. Diameter of calices, about
3mm.

Occurrence in the lower Tejon Eocene, from locality 476, on south
side of Mount Diablo, Contra Costa County, California.

In the type locality this species occurs with the following char-
acteristic Tejon species: Turbinolia pusillanma, n.sp., Ficopsis
remondii Gabb, Leda gabbi Conrad, Meretrix horni Gabb, Tellina
remondii Gabb, Turritella merriami Dickerson, Venericardia plan-

costa horn (Gabb).

GONIOPORA VAUGHANT, n. sp.
Plate 3, figures 18, 19

Type in collections of California Academy of Sciences, San Francisco, from
locality 101.

Corallum composite, in type incrusting a fragment of Ostrea.
Corralites crowded into polygonal forms with distinct, shallow, calices.
Septa twenty-four, thick, perforate, in three cycles, apparently fused
in bilateral arrangement characteristic of the genus. Synapticula
very numerous, arranged around the columella so as to appear as
rather definite circles. Columella well developed, spongy. Diameter

of corallites about 2.7 mm.

1916] Nomland: Corals from Cretaceous and Tertiary of California 69

Oceurrence at California Academy of Sciences locality 101, along
sea-cliff about two miles north of Delmar, San Diego County, Cal-
fornia. In the Tejon Eocene.

FAMILY GORGONIDAE

The material at hand consists of one imperfect specimen, shown on
plate 4, figure 6. This species seems to belong to the gorgonian corals,
although the material does not warrant a description. This specimen
is from locality 1853, Chico, Marysville quadrangle, California.
Material in collections of Department of Palaeontology of the Uni-
versity of California.

Other fragmentary material shown on plate 4, figures 7 and 8, seems
to indicate that the coral belongs to the family Gorgonidae. No specific
determination could be made, however. From locality 172 of the Cali-
fornia Academy of Sciences, in a small bluff in the SW corner of Com-
mercial and Fifth streets, Astoria, Oregon, probably in the Astoria
series Oligocene.

TROCHOCYATHUS ZITTELI Merriam

Some forms of Trochocyathus zitteli Merriam’ resemble very closely
?2Smilotrochus curtis Gabb.* Seores of specimens of 7’. zitteli have
been collected by Merriam, Dickerson, and numerous field classes in
palaeontology at the same general locality as that indefinitely given as
the type locahty of S. curtis, but not one specimen of this species has
been reported. It is therefore possible that the two are the same.
Gabb’s type material consisted of only two very imperfect specimens
which cannot now be located for comparison, and the evidence seems
to be insufficient for placing 7. zitteli in synonomy with S. curtis.

1U.8. Geol. Surv., Monograph 39, 1900.
2 Geol. Surv. Calif., Palaeontology, vol. 2, 1869.

Transmitted February 26, 1915.

ron
Fig. 2.
Bigs 3:
Fig. 4.
Fig. 5.
Fig. 6.
Fig. 7.
Fig. 8.
Fig. 9.
Fig. 10.
Fig. 11.
Fig. 12
Fig. 13.
Fig. 14.
Fig. 15
Fig. 16.
Fig. 17
Fig. 18.
Ike

EXPLANATION OF PLATE 3

Flabellum(?) merriami, n.sp., upright view of type. xX 5.

Flabellum(?) merriami, n.sp., another view of the specimen shown in
figure]. X 4.

Flabellum(?) merriami, n.sp., a slender specimen. X 4.
Flabellum(?) merriami, n.sp., view of base of fig. 3. xX 5.
Turbinolia dickersoni, n.sp., upright view of type. X 5%.

Turbinolia dickersoni, n.sp., cross-section near middle of small speci-
men. X 4.

Turbinolia dickersoni, n.sp., calicular view of fig. 5. xX 5.

Turbinolia dickersoni, n.sp., Showing ornamentation of septal faces.
x 5.

Turbinolia pusillanima, n. sp., upright view of imperfect type specimen.
x 4.

Turbinolia pusillanima, n. sp., cross-section short distance below calice.
x 4.

Stephanophyllia californica, n.sp., calicular view of rather small speci-
men. X 3.

Stephanophyllia californica, un.sp., side view of specimen shown in
figure 11. X 3.

Stephanophyllia californica, n.sp., view of base of specimen shown in
figure 11. xX 3.

Astrangia insignifica, n.sp., view of calice. X 3.

Astrangia insignifica, n.sp., side view of specimen shown in figure 14.
x 3.

Trochocyathus pergranulatus, n.sp., cross-section. x 3.

Trochocyathus pergranulatus, n.sp., upright view of imperfect type.
x 3.

Goniopora vaughani, n.sp., general view of corallum. X 114.

Goniopora vaughani, n.sp., view of ealices. X 3.

[70]

UNIV CALIF: PUBIE, BUIEE. DEPT. GEOL, [NOMLAND] VOL. 9, PL. 3

: i ; Hi
Goi! r n r :
ee ees i ' f
” joss t)
Fy i " 9 -
+ ‘
'
=
'
ee
*
n
‘

Fig. 1.
Fig. 2.
Fig. 3.
Fig. 4.
Fig. 5.
Fig. 6.
Bn oT.
Jee, teh
Mics 9;
Fig. 10.
Fig. 11.
Fig. 12.
Fig. 13.
Fig. 14.
Fig. 15.
Fig. 16.
Fig. 17.

EXPLANATION OF PLATE 4

Dendrophyllia tejonensis, n. sp., general view. X 2.

Balanophyllia variabilis, n. sp., cross-section some distance below calice.
ee:

Balanophyllia variabilis, n. sp., cross-section near calice. X 2.

Balanophyllia variabilis, n.sp., upright view of short specimen. X 2.

Dendrophyllia tejonensis, n. sp., cross-section of a branch. X 3.

Gorgonia sp., general view. X 1%.

Gorgonia sp., general view. X 14.

Gorgonia sp., general view. X 114.

Trochocyathus oregonensis, n.sp., cross-section. x 3.

Trochocyathus oregonensis, n.sp., upright view of type. X 144.

Trochocyathus imperialis, n. sp., general view. X 2.

Trochocyathus imperialis, n.sp., cross-section some distance above base.
xX 2.

Balanophyllia variabilis, n. sp., general view of type. X 1%.

Flabellum californicum Vaughan, specimen from type locality. x 2.

Flabellum californicum Vaughan, cross-section. X 2.

Flabellum californicum Vaughan, showing specimen not curved in plane
of shorter transverse axis. X 2.

Flabellum(?) merriami, n. sp., cross-section. xX 4.

UNIV. GALIE. PUBL, BUIEE, DEPT. GEOL [NOMLAND] VOL. 9, PL. 4

EXPLANATION OF PLATE 5

Madripora solida, n.sp., general view. X 114.

Madripora solida, n. sp., cross-section of one of smaller branches.
Siderastrea clarki, n.sp., general view of corallum. X 1%.
Siderastrea clarki, n. sp., view of corallites. X 2.

Thamnasteria sinuata, n.sp., general view of fragment. X 114.

Thamnasteria sinuata, n.sp., transverse section across corralites.

[74]

x 2.

2S A

VINIV (CALIF. RUBE. BULED DEPT. GEOL [NOMLAND] VOL. 9, PL.

\\

H

bo

EXPLANATION OF PLATE 6

Dendrophyllia hannibali, n.sp., general view showing branching. X \%.

Dendrophylia hannibal, n.sp., view of a branch showing costal develop-
ment. X 1.

Dendrophylliia hannibali, n. sp., cross-section below ecalice. X 3.

[76]

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 6, pp. 77-88, plate 7 Issued January 20, 1916

RELATION OF THE INVERTEBRATE TO THE
VERTEBRATE FAUNAL ZONES OF THE
JACALITOS AND ETCHEGOIN FOR-
MATIONS IN THE NORTH
COALINGA REGION,

CALIFORNIA jana
BY
JORGEN 0. NOMLAND

CONTENTS
PAGE
DES UW CO es Ree Pee pel oso, eeet es Fedues gaa teestscatasseese tess 77
TEARS RO a OE ae he se ee eee 78
Jacalitos and Etchegoin Northeast of Coalinga -.......2222..22.20..2.22..2.20-20022eceeeeeee ee 79
Iniy erbebr ate Watmal A OMCs occ 2 ke ocde sacle csed skatuaeccesvebsdaveesoeers te neecullbtioees a 81
Wien bebrate gaan alll ZOMCS creetece: secescctee oftececoeeccss2eeteefeccecsoeciccetacecsesecixinss.=seasssecaccsssesbeesees 83
RS RDG 0 Cy eer ue ae gh RE I SQ Oa 84

Section showing Time Relationship of Invertebrate and Vertebrate Faunal

Zones in the Jacalitos and Etchegoin Formations near Coalinga ................ 85
WMesermptions of New: SPeCess ..cck ee eons cee eed ieee ate gh caeeesectacevsccstennceon-deeectenes 85
Calliostoma etchegoinensis, n. SP. -.-......-22..-.--22-c2-ceceeceeceeceeeceeceeeeeeeeeeecteceeeeeseeeees 85
PAT UT AGCUTTIS pS) s) Seecret rc ceee es caeeeetee 2 vv tee Sect ents ss eeeeys setae wees avearsaeteee 86
ANATUC ANC OMVEXaisMaiS Peyceceee oe sosee secs sezeeecesceccns2dlesscedesscees2beec2eszenesscsesescteneee-eccesutecechers 86

INTRODUCTION

In a recent publication by Professor J. C. Merriam’ attention was
called to the finding of vertebrate fossils in the Jacalitos and Etchegoin
formations near Coalinga, Fresno County, California. It was also
pointed out that these vertebrate remains have been found in zones
having a quite definite relationship to the invertebrate faunal zones

1 Merriam, J. C., Tertiary Vertebrate Faunas of the North Coalinga Region,
Trans. Amer. Philos. Soc., vol. 22, part 3, 1915.

78 University of California Publications in Geology [ Vou. 9

in this region. Since this occurence offers a somewhat unusual oppor-
tunity for the comparison of the invertebrate and vertebrate time-
seales of California in the upper Miocene and lower Pliocene and of
the invertebrate faunal zones of the western with those of the eastern
part of the continent, a more or less detailed description is here
presented.

The locality at which this relationship of vertebrate and inverte-
brate faunal zones has been studied is located about nine miles north-
northeast of Coalinga and east and northeast of the small town of
Oilfields. The eastern foothills of the Coast Ranges here show
exposures of the Jacalitos and Etchegoin formations. The Tulare is
exposed only to a very limited extent at Anticline Ridge. The region
examined forms a rectangular strip extending in a north and south
direction and has an areal extent of somewhat more than a_ half
township.

HISTORICAL

The first paper dealing definitely with this region was published
by F. M. Anderson.? This was followed a few years later by another
publication on this region by the same author.* According to Anderson,
the later Neocene may here be divided into the Coalinga beds and
the Etchegoin beds. The latter were subdivided into the Etchegoin
sands and San Joaquin clays. The type section of his Etchegoin beds
is located in the neighborhood of the old John Etchegoin ranch about
fifteen miles northeast of Coalinga. A persistent fossil horizon is
mentioned as occuring somewhere near the base. This was later named
the Glycymeris zone by Arnold and Anderson and used as the typical
basal Etchegoin in their mapping of the Coalinga field.

In a bulletin published by Ralph Arnold and Robert Anderson*
the Coalinga beds of F. M. Anderson were divided into three forma-
tions, the lowest of which was called the Vaqueros, above this the
Santa Margarita, and uppermost the Jacalitos. The Jacalitos for-
mation was defined as being above the basal gravels and fossil wood
zone overlying the fossiliferous Santa Margarita. At the top the
Jacalitos was defined as being below the Glycymeris zone at the base
eneron F. M., A Stratigraphic Study in the Mount Diablo Range of Cali-
fornia, Proc. Calif. Acad. Sci., 3rd ser. vol. 2, no. 1, 1905.

3 Anderson, F, M., A Further Stratigraphic Study in the Mount Diablo Range
of California, Proce. Calif. Acad. Sci., 4th ser., vol. 3, 1908.

+U.S. Geol. Surv. Bull. 398, 1910.

1916] Nomland: Invertebrate Zones of Jacalitos and Etchegoin {he}

of the Etchegoin. In this paper Arnold and Anderson stated that
for the Etchegoin, ‘‘The upper limit is not defined for the hills north
of Coalinga owing to the indefiniteness of the line between the Etche-
goin and Tulare there.’’ As will be shown in this paper, the Mya
zone, which corresponds to the uppermost Etchegoin in other parts
of this district, and also other corresponding zones have been dis-
covered north of Coalinga in the typical section of that formation.

JACALITOS AND ETCHEGOIN NORTHEAST OF COALINGA

The base of the Jacalitos as defined here is the first gravel above the
fossiliferous Santa Margarita formation. This is taken from the
detailed mapping of J. H. Ruckman,’ according to whom some of the
thick beds of gravel seen near the anticline become thinner and also
more sandy and finally shaly on being traced northward. Ruckman
also shows that the basal gravels unconformable above the Santa Mar-
garita consists of a member somewhat lower than the one mapped as
such by Arnold and Anderson. In these basal gravel beds we find a
large amount of silicified wood and gypsum. Immediately above this
occurs a member of brown, red, gray, and otherwise highly colored
clays. Leaf impressions are abundant. These conditions seem to
indicate that these beds are terrestrial deposits.

About two hundred feet above the base we have other gravel beds
which seem to have been mapped as the basal Jacalitos by Arnold and
Anderson. Possibly these beds may be unconformable with the under-
lying clays. It was in this zone that Arnold and Anderson reported
finding a tooth of Pliohippus. From these gravels upward to the top,
the Jacalitos consists largely of soft yellowish clays with interbedded
vivianitic sandstone and conglomerate.

The exact relations of the Jacalitos and Etchegoin as mapped by
Arnold and Anderson in the field north of Coalinga are a matter of
doubt, since we have in the northern field two series of beds appar-
ently conformable, in the lower of which no invertebrate fauna has
been found. The two series of beds in the southern part of the district
with which the Jacalitos and Etchegoin here described have been
correlated are, however, said to be unconformable and to have faunas
which are somewhat different.

In the basal Etchegoin the low, dark bluish-colored hills show
exposures of a coarse-grained, slightly consolidated, vivianitie sand-

5 Publication in press.

80 University of California Publications in Geology [ VoL. 9

stone. The texture is uniform in the same members of the beds.
Different members may, however, be very different in texture as well
as in other characteristics. The lowest beds have a dip of 10° E, the
dip becoming slightly less in the upper part of the formation.

At a short but variable distance above the Glycymeris zone, or
lowermost Etchegoin, an unconformity was traced from see. 1,
T. 19 8, R. 15 E, southward to Anticline Ridge, a distance of about
seven miles. The beds below could be traced to the beds above,
being cut off by the unconformity. At one locality where the beds
below the unconformity were composed of hard clay, inclusions of
this clay were found in the sandstone above. No difference in dip
could be discovered between the beds above and below the irregular
contact. Locally the member above has a basal conglomerate as at
Antichne Ridge, where it has a thickness of fifteen feet or more and
has been used as a gravel pit. A good exposure may be seen at sec. 1,
T. 19 8, R. 15 E, where a fault block has brought into view the un-
conformity but not the fossiliferous zone beneath. As seen by the
description given, this unconformity may be of only local importance.
This also seems to be shown by the finding of the same species of horse
both above and below.

Beginning a short distance above the basal beds and continuing
upwards for several hundred feet a striking characteristic cross-
bedding has its maximum development. These beds are made up
almost entirely of a coarse-grained vivianitic sandstone. The cross-
bedded members are as a rule abruptly cut off both above and below
by clay strata or beds of conglomerate which have a dip of 10° E.
Except that the material of which the eross-bedded sandstones are
composed seems to become progressively finer in the upper portion,
these beds seem to have been deposited under conditions somewhat
similar to those under which the parallel stratified beds beneath were
deposited. The beds below contain marine fossils.

In going upward from the basal Etchegoin beds no member could
be followed along the strike continuously over one or two miles until
thirteen hundred feet above the base. At that position oceur two
bands of a white ashy shale mixed in some places with a fine white
sand. The fossils found in the upper of these bands show that this
corresponds to the Mya zone of the uppermost Etchegoin in the
Kettleman Hills and the Kreyenhagen Hills as described by Arnold
and Anderson. This zone was traced for eight or nine miles as a low

1916] Nomland: Invertebrate Zones of Jacalitos and Etchegoin 81

ridge in the outermost foothills. At one locality about fifty feet below
the upper shale band a bed of porous, white, fine-grained tuff with a
small quantity of interstratified quartz sand was found. In the upper
half of the formation, on approaching the anticline from the north,
several other shale members together with additional invertebrate
zones make their appearance. In this region relatively little vertebrate
material is present. This may perhaps be due to deeper water here
than farther north during deposition.

INVERTEBRATE FAUNAL ZONES

No invertebrate fossils have thus far been found in the seventeen
hundred feet of sands, gravels, and clays mapped as Jacalitos. Strati-
graphically, however, these beds seem to form a continuous, conform-
able series, at least from Arnold and Anderson’s basal gravels, up to
the unconformity above the Glycymeris zone. This zone can be traced
almost continuously for nine or ten miles. About forty feet above it
another zone appears at intervals. South of Oilfields for a short dis-
tance Glycymeris coalingensis Arnold is found in great abundance.
On going north, however, Tamiosoma, ef. gregaria Conrad and Mulinia
densata Conrad are the more common species.

The invertebrate fauna of the Glycmeris zone and the one a short
distance above it consists of the following species :

ECHINODERMATA
Eechinarachnius gibbsii Rémond

CIRRIPEDIA
Balanus, sp. Tamiosoma, ef. gregaria Conrad
PELECYPODA
Area trilineata Conrad Margarita johnsoni Arnold
Cardium corbis Martyn Panopea generosa Gould
Cryptomya ovalis Conrad Paphia staleyi Gabb
Cryptomya quadrata Arnold Pecten wattsi Arnold
Glycymeris coalingensis Arnold Pecten oweni Arnold
Glycymeris septentrionalis Mid- Pecten estrellanus Conrad, var.
dendorf terminus Arnold
Macoma inquinata Deshayes Phacoides, sp.
Macoma nasuta Conrad Sanguinolaria nuttalli Conrad
Macoma secta Conrad Saxidomus nuttalli Conrad
Metis alta Conrad Schizothaerus nuttalli Conrad
Modiolus, sp. Solen sicarius Gould
Mulinia densata Conrad Spisula albaria Conrad
Mytilus coalingensis Arnold Spisula coalingensis Arnold

Ostrea atwoodi Gabb Tellina bodegensis Hinds

82 University of Califorma Publications in Geology [ Vou. 9

GASTROPODA

Nassa californica Conrad
Neverita convexa, n. sp.

Calliostoma coalingensis Arnold
Calliostoma etchegoinensis, n. sp.
Calyptraea filosa Gabb Olivella biplicata Conrad
Columbella (Astyris) richthofeni Pleurotoma coalingensis Arnold
Gabb Thais lamellosa Gmelin
Crepidula onyx Sowerby Thais kettlemanensis Arnold
Lunatia, sp. Turritella vanvlecki Arnold

About two miles north of Anticline Ridge and six hundred feet
stratigraphically above the Glycymeris zone occurs another zone char-
acterized by a great abundance of a thin variety of Echinarachnius
gibbsii Rémond. The fossils are found in a bed of yellowish, sandy
clay which is only a short distance above the highest vivianitic sand-
stone that occurs at this locality. This seems to correspond to the
Lower Middle zone of the Etchegoin as mapped by Arnold and
Anderson in the southern part of the district. The following species
have been found at this horizon :

Crepidula onyx Sowerby

Cryptomya quadrata Arnold
Echinarachnius gibbsii Rémond,

Mytilus, ef. edulis Linne
Mytilus coalingensis Arnold
Olivella biplicata Conrad
Saxidomus nuttalli Conrad
Schizothaerus nuttalli Conrad
Solen, sp.

thin variety.
Lunatia, sp.
Macoma inquinata Deshayes
Metis alta Conrad

A few hundred feet above the zone last described another zone was
found with vertebrate material at the same locality. The invertebrate
material, being in a very poor state of preservation, could not be
identified except as follows:

Neverita, sp.
Pecten, sp.

Area trilineata Conrad
Macoma, sp.
Mytilus, sp.

About one hundred feet below the Mya japonica zone near the
anticline a band of white shale oceurs in which are found a large
number of fragments of Pecten nutteri Arnold. The presence of this
species and its stratigraphic position seem to place this as the equiva-
lent of the Upper Middle beds, or the Pecten coalingensis zone south of
Coalinga. The following species were collected :

Area trilineata Conrad
Calyptraea filosa Gabb
Pecten nutteri Arnold

Cancer
Fish vertebrae

1916] = Nomland: Invertebrate Zones of Jacalitos and Etchegoin 83

The beds in which Mya japonica Jay occurs consist of an ashy shale.
Gypsum and silicified wood are abundant. The peculiar, so-called
bulbous fish growths of many variable shapes form an almost con-
tinuous zone here. One of these seemed to be a somewhat water-worn
eanine tooth. The fauna represents littoral conditions. The indications
therefore, seem to be that the Etchegoin sea was growing shallow before
passing into the Tulare fresh-water or alluvial beds, as shown by
exposures in the Kettleman Hills directly above the Mya zone. The
fauna of this zone consists of :

Glyeymeris septentrionalis Mid- Macoma, sp.
dendorf Mya japonica Jay
Littorina mariana Arnold Solen sicarius Gould

Immediately below this, or between the two shale bands, the following

forms were found:
Mulinia densata Conrad Tamiosoma, ef. gregaria Conrad

VERTEBRATE FAUNAL ZONES

As has already been mentioned, a large quantity of fossil leaves and
petrified wood is found in the highly colored, perhaps land-laid beds
mapped as basal Jacalitos. This collection may, when carefully studied,
assist in determining the age of this formation. In these beds fossil
remains of the three-toed horse Neohipparion molle Merriam were
found.

The finding of Pliohippus? in the gravels two hundred feet above
the basal Jacalitos, or in the bed mapped by Arnold and Anderson as
their lowest Jacalitos member, has already been mentioned in this
paper.

Above this no invertebrate or vertebrate fossils have thus far been
found until reaching the Glycymeris coalingensis zone, or lowest
Etchegoin. The Pliohippus stage of the development of the horse is
represented here in the basal beds and a few hundred feet upwards.
This zone has therefore been called the plhohippus coalingensis zone
by Professor Merriam.

Beginning near the Lower Middle invertebrate zone and extending
upward to the uppermost Etchegoin or Mya zone, we have the oceur-
rence of mastodon, two very different species of camel, a member of
the deer family, and a large horse much like Equus or possibly Plio-
hippus. The very recent aspect of at least a part of this fauna has
cast doubt upon the occurrence of these fossils, and the question has
been raised whether these remains may not occur in terrace material.

84 University of California Publications in Geology [ VoL. 9

The larger streams show evidences in the lower valleys of at least
three periods of terracing, perhaps largely due to aggraded streams.
Although in the region to the north, as at Domengine Creek and
Cantua Creek, there are evidences of far higher terraces, in the region
where the vertebrate remains are found there are now no evidences
of terraces and if terrace deposits were ever present they are now
completely removed from the bare outcrops of Etchegoin strata. None
of the terrace material characterized by fragments of Ostrea titan
Conrad and Pecten estrellanus Conrad brought from the Santa Mar-
garita and none of the red and black pebbles brought from the Chico
are here present. At one locality several horse teeth were found near
the top of a sharp hill with very evident outcropping strata of a
compact resistant shale. It seems odd that, if general terracing of the
region has taken place and nearly all of the deposits have been removed,
we do not find this fauna upon the lower part of the Etchegoin or at
the localities in the Jacalitos which are of no greater elevation. On
the contrary, the bone fragments in some places seem to occur along
zones, following the outcropping strata, and collecting could be done
with success only by following these beds.

SUMMARY

As has been stated, the faunal zones of the Etchegoin correspond-
ing to similar zones in the southern part of this district appear to
occur here in the type section of the formation. The uppermost
of these corresponds to the Mya zone, which in the Kettleman Hills
is immediately below the Tulare formation. Hence we apparently
have exposures of the complete Etchegoin section in this area. Near
the base of the Etchegoin an unconformity has been found which
perhaps may prove to be of some importance when a wider and more
careful study has been made. Vertebrate faunal zones have been found
in both the Jacalitos and Etchegoin formations. These have a relation
to the invertebrate faunal zones that tends to throw light upon the
interrelation of the two faunal time-scales of the Pacifie Coast. As
shown by the studies of Professor Merriam,® the evidence seems to
indicate that the invertebrate horizons referred to the upper Miocene
and lower Miocene have been placed somewhat lower than the cor-
responding horizons of the eastern part of this continent and of
Europe.

6 Merriam, J. C., Tertiary Vertebrate Faunas of the North Coalinga Region,
Trans. Am. Philos. Soe., vol. 22, part 3, Philadelphia, 1915

1916] Nomland: Invertebrate Zones of Jacalitos and Etchegoin

wm
or

SECTION SHOWING STRATIGRAPHIC POSITION OF INVERTEBRATE AND VERTEBRATE
FAUNAL ZONES IN THE JACALITOS AND ETCHEGOIN FORMATIONS NEAR COALINGA

TULARE {
Mya Zone Shale, gypsum, tuff,
Upper Middle clays. Occurrence of Equus or Plio-
Tone hippus, mastodon, camels,
ete.
Yellow clays
ETCHEGOIN Lower Middle
Zone
pence! Cross-bedded_ viv-
lanitie sandstone,
clays, conglomer-
ate.
Glyeymeris Uneonformity. Pliohippus coalingensis
Zone (Merriam).
Yellow clays.
Vivianitie sand-
stone, clays.
J ACALITOS
1700 feet Colored clays,
sands.
Conglomerate. Pliohippus?
““Red beds.’’
Unconformity Neohipparion molle Merriam.
SANTA
MARGARITA

DESCRIPTION OF NEW SPECIES
CALLIOSTOMA ETCHEGOINENSIS, n. sp.
Plate 7, figure 3

Type from University of California locality 2096 in the Etchegoin formation,
northeast of Oilfields, California.

Shell conical, apex subacute. Whorls about five, with nearly
straight sides, the angle of body-whorl very sharp and base flattish.
The sculpture on the sides of the whorls consists of three or four
revolving ridges, the bottom one being the smallest, and fine inter-
calaries between each pair of the upper two or three; the upper

86 University of California Publications in Geology [| Vou. 9

surface of whorls has four spiral ribs, of which the posterior is much
more prominent, this giving the top a tabulate aspect which is not
due to impression at suture; at the base are a number of slightly
nodose, spiral ribs of which the two inner are the most prominent.
Suture slightly impressed, between two strong revolving ridges. All
the major ribs and interealaries are nodose.

Height, 16.2 mm.; maximum diameter, 16.7 mm.

This species resembles rather closely Calliostoma coalingensis
Arnold, also found in this district. In Calliostoma etchegoinensis,
n.sp., however, all the ribs have well-developed nodes, and the tabulate
upper surface of whorls is not at the suture but extends from a strong
ridge immediately below suture to the upper ridge on sides of whorls.

PURPURA TURRIS, n. sp.
Plate 7, figure 4

Type in collections of University of California Department of Palaeontology,
from locality 2110.

Shell thick, medium in size, spire and canal short, turreted; whorls
about six, shouldered, channeled immediately below suture; mouth
subovate, outer Lp much thickened; canal open, inclined slightly to
the left; body-whorl ornamented by about seven revolving ribs, of
which four are more prominent, of the ten longitudinal varices on
body-whorl of type two are heavier and lamellar.

Height, 40 mm.; maximum diameter, 28.5 mm.

Occurrence in the lower Etchegoin formation, west of Coalinga, at
University of California locality 2110.

NATICA (NEVERITA) CONVEXA, n. sp.
Plate 7, figures 1, 2

Type from University of California locality 2091.

Shell slightly ovate with elevated spire; whorls about four, strongly
convex, becoming somewhat flattened near the top, giving the whorls a
slightly tabulate appearance; near the mouth the lower part of body-
whorl curves downward considerably; surface covered by numerous
oblique incremental lines; suture distinct, not appressed; umbilical

1916] = =Nomland: Invertebrate Zones of Jacalitos and Etchegoin 87

callus large, rather prominent, completely covering the umbilicus, no
groove present on its surface.

Height of type, 17.8 mm.; greatest diameter, 16.5 mm.

Occurrence at University of California localities 2091, 2093, 2096,
in the Etchegoin formation northeast of Coalinga, California.

This species is distinguishable from Natica recluziana Petit, which
is also found in this district, by the convexity of the whorls, the
tabulate appearance, and the downward curving of the body-whorl
near the mouth.

Transmitted February 26, 19165.

bo

ioe

EXPLANATION OF PLATE 7
Natica (Neverita) convexa, n.sp., front view, natural size.
Natica (Neverita) convexa, n.sp., posterior view, natural size.
Calliostoma etchegoinensis, n. sp., posterior view, natural size.

Purpura turris, n. sp., natural size.

[88]

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, VOLUME 6.

. The Condor-like Vultures of Rancho La Brea, by Loye Holmes Miller...-.......-ce.cce---- 58

. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern :
Nevada, by John C, Merriam. Part I.—Geologic History .....1.....-.-.c-sc-sessseseeeseeceseraee —50e

. The Geology of the Sargent Oil Field, by William FP. Jomes .......-...-c.1e-sssssss-sssnecnenseee 25¢e—

| Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, by x,
Taoye Holmes Mailer ....22.p::c.2--::eniceeconnceennensnongiesonesepinesdienp enna vone ennseeisiguses sehen 10:

5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A. Reid 60¢

6. Note on a Gigantie Bear from the Pleistocene of Rancho La Brea, by John GC.
Merriam. ie

7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Desert,

by John C. Merriam.

he CO pe

Nos. 6 and 7) im OMG) COVED a)... co. ccc cccccedensoenescncneubiacilewnscns-ncedupuedaucs ieee gee 10¢

8. The Bieiteraniie and Faunal Relations of the Martinez Formation to the Chico
aud Tejon North of Mount Diablo, by Roy E. Dickerson ......... 2. ss-c:cecsensracnnscnens 5e
9, Neocolemanite, a Variety of Colemanite, and Howlite from Lang, Los Angela ry!
County, California, by Arthur S. Hakkle 2.0.2.0 o.:-cccctccncecc-ce-s-tl son eae 10e

10. A New Antelope from the Pieistocene of Rancho la Brea, by Walter P, Taylor... D
il, Tertiary Mammal Beds of Virgin Valicy and Thousand Creek in Northwestern :

Nevada, by John ©. Merriam. Part I1.—Vertebrate Faumas ......3.cccccccescsecsansenescen 1 00
12. A Series of Eagle Tarsi from the Pleistocene of Rancho La Brea, by Loye Holmes +
Miller: «2-2-2 ieee nshe deena be earn ccc hepa dit a Renna nantli ae eae rr i

13. Notes on the Relationships of the Marine Saurian furad Described from the Triassie¢
of Spitzbergen by Wiman, by John C. Merriam.
14. Notes on the Dentition of Omphalosaurus, by John C. Merriam and Harold C. Bryant.

Nos. 18 and 14 im ome COVEr 2..2._---2--j-be-ececce- nce cpe nade seesencteennniene dete cee ean
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California, by Charles Laurence Bakker 2 0cci.25c2-ocecteccecerngescseesomncenteeeseaieaeeeeee aes

16. Avifauna of the Pleistocene Cave Deposits of California, by Loye Holmes Miller...

. A Fossil Beaver from the Kettleman Hills, California, by Louise Kellogg ........-
18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam .........20-..:ec-scenss ee
19. The Elastie-Rebound Theory of Earthquakes, by Harry Fielding Reid ............... pee

VOLUME 7.

1. The Minerals of Tonopah, Nevada, by Arthur S. Hakle ssc

2. Pseudostratification in Santa Barbara County, California, bi George Da is
DeCK ice enesciierccrnsonebde stat bibatimensios dass vaedoe teehee i Mila bree ak Ie ia see ee re

3. Recent Discoveries of Carnivora in the Pleistocene of Rancho La Brea, by J
Merrie enon o dc caches essen ce boos i seecanep nm do ices ae gece doko aa ge eee

4. 'The Neocene Section at Kirker Pass on the North Side of Mount Diablo, by
b FE 01 C5): dues EONS Me Mina ene Ce Neo A -Prenawemh Th, A RE

5. Contributions to Avian aboard vad from the Pacific Coast of North 4
oye \Holties) Miller 2.008) 080 a ee

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 7, pp. 89-96, 2 text-figures Issued March 10, 1916

A REVIEW OF THE SPECIES PAVO
CALIFORNICUS

BY
LOYE HOLMES MILLER

CONTENTS

PAGE

WUiyartsTs© UU C UNO Ma vee seers tre acces eee eee ac ceek seer ec sv eoe ee 2 Seneca sees SED vos Cone seee deve vaceediasuceten-eboreancnoess 89
WD Stale Ge) 1SCUSS1 OM eress eee ca. <2 k ences cae ce nace ceceeeccecersecseececcieees-se=ces2ecce<eceeeaceerscees eoseseceseieis 90
MANS OMG LAT ATS US peetcess eer e sofas cece oe cee Jee cnc ae ee eer eee ages oe econ tat ake eee toe a 90

GAM OOS AEE SI OVS) ee et ee ee ee Re 91
TEMES 6 OU a a FN OP SOE ae 2 93

Ves RAN ONES WAS] 2g ase A SS 2 Ee ae eS, 94

(CRO ENC Le ee 94

© DTD O TOC LOC EVE US peessereceesc ccs e reece cw eue cee een pane teeasu ace Setes SEL gs sateens axes Secs <doncuseeseeze 94
COM CUUST OT Spores eee nee ate serene eee. 9, Dia eeeeniaeee 2 Bree, eee, 22 ee ee 95

INTRODUCTION

At the close of the first excavation of the University of California
at Rancho La Brea, there were found among the avian remains result-
ing from this work a small number of very imperfect specimens
representing a large gallinaceous bird of unknown affinities. Later
in the same locality, the perfect tarsometatarsus of an adult male of
presumably the same species was taken by the present writer and a
second specimen of the same bone was generously donated by Mr. E.
J. Fischer of Los Angeles. These perfect specimens constituted the
material from which was described the new species Pavo californicus
Miller’ and the type specimen was deposited in the palaeontological
collections at the University of California.

At the time the original description was published, Meleagris
gallopavo (domestic) was the only meleagrine available for com-
parison. Recourse was had to the extensive monograph of Milne-

1 Miller, L. H., Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, no. 19, p. 285, 1909.

90 University of California Publications in Geology — [Vou. 9

Edwards? in which he figures and compares Meleagris, Pavo, and other
phasianids. Also some measurements were made upon the shank of
a live male Pavo cristatus. With the material at hand it seemed
proper to refer the fossil species to the genus Pavo despite the some-
what startling nature of such announcement.

After the lapse of some time the University had opportunity to
make further and much more extended exploration of the asphalt
beds, which resulted in the assembling of a representative series of
Pavo remains, including most of the characteristic bones and a goodly
series of the type segment, the tarsometatarsus. Related Recent
species are also more perfectly represented. There are at hand com-
plete skeletons of Pavo cristatus in native phase, Meleagris ocellatus,
both sexes, and most of the skeleton of Meleagris gallopavo in native
phase. An opportunity to examine a large series of skeletons of the
Recent Meleagris gallopavo in native phase at Yale University was
afforded the writer by Professors Schuchert and Lull of that institu-
tion. In the presence of this additional material both Recent and
fossil it seems proper to review the entire question of the relationships
of the extinct species from Rancho La Brea, described in 1909 as

Pavo californicus.

DETAILED COMPARISON

Tarsometatarsus.—A splendid series of twenty-five complete tarso-
metatarsi now represent Pavo californicus in the collections of the
University of California. In considering this series of the type seg-
ment, there is noticeable a marked degree of variation in the total
length and in the actual elevation of the spur core; the relative eleva-
tion of the spur, however, shows but little variation, remaining between
forty and forty-one per cent of the total tarsal length. The age of
the individual is judged from the length and the strength of the spur
core and from the degree of ossification of the plantar tendons. With
these criteria as a basis of age determination, it is seen that the length
of tarsus is not directly proportional to age. The longest tarsometa-
tarsus has the weakest spur and the strongest spur is found on the
shortest adult bone.

2 Milne-Edwards, A., Oiseaux fossiles de la France, Paris, 1867-77.

3 For the valuable Meleagris material grateful acknowledgment is made to
Dr. L. A. Test of Missouri State School of Mines and to the National Museum
of Mexico.

1916 | Miller: Review of Pavo Californicus on

The stoutness of the shaft is remarkably constant for a praecocial
bird of the size of Pavo. The extremes of transverse diameter in birds
old enough to bear the spur are only 0.7 mm. apart.

One of the characters by which Pavo is set off from Meleagris is
the presence of an incipient third ridge between the inner and the
outer ridges of the hypotarsus. This ridge is almost entirely wanting
even in old specimens of Meleagris gallopavo but is present in Pavo
californicus before the ossification of the plantar tendons, and_ is
equally marked in both sexes. This incipient ridge is but faintly
indicated in M. ocellatus in both sexes, although both specimens at
hand are fully adult. With respect to this character, the four species
under consideration fall into the following progressive series: J. gallo-
pavo, M. ocellatus, P. cristatus, and P. californicus. The outer ridge of
the hypotarsus is short and is dropped downward in Meleagris, is longer
and less prominent in Pavo cristatus, is longest and most prominent in
P. califormcus. In the development of the spur and in the shape of
the spur core, P. californicus resembles Meleagris ocellatus more than
it does Pavo cristatus. In the elevation of the toes, the fossil form is
more like M. ocellatus than like P. cristatus. In elevation of the spur
it is almost identical with P. cristatus and far removed from J.
ocellatus.

From the study of this bone only, the fossil species would seem
as far removed from either living species as the two living species are
from each other.

In the original description of Pavo califormcus, the statement was
made that the sexes were alike except for the presence or absence of
the spur core. This statement was based upon the erroneous con-
clusion that the fossil species followed Meleagris gallopavo in develop-
ing the spur as early as the ossification of the plantar tendons. <A
young male specimen with the plantar ridge present but with the spur
lacking was identified as an adult female. With the present series
before one the error of this conclusion is easily noted.

Tibiotarsus.—It will be seen from the above study of the tarso-
metatarsus in the Recent Pavo and the ocellated turkey that, while
the bones in the two species are almost identical in length, the shaft
of the bone is appreciably heavier in Pavo. The exact reverse is found
to be true in comparing the tibiotarsi of the same two individuals.
The total length of this segment in the peacock is 197.7 mm., in the
ocellated turkey it is 187. The transverse diameter of the shaft is
8.5mm. in the former and 9mm. in the latter.

92 University of California Publications in Geology [ VoL. 9

Fig. 1. Parapavo californicus. Tarsometatarsus. 1, Graph showing total length
in a series of males, natural size; 2, the same for a series of females. Heavy ver-
tical lines represent actual lengths of specimens.

1916] Miller: Review of Pavo Californicus 93

Viewed from in front these bones show the enemial crest in J.
ocellatus more abruptly thrust over toward the outside and the distal
condyles less widely separated, although the tunnel under the osseous
bridge is larger. In all these respects, the affinities of the fossil species
are with Pavo rather than with Meleagris. Beyond these points there
Hypotarsus
Nature of spur
Hlevation of spur
Elevation of toes
Tibiotarsus

Femur

Humerus

Head flexure of
coracoid

Scapular sear of
coracoid

Intermuscular lines
on coracoid

General proportions
of coracoid

Interdigital tubercle
on carpometacarpus

Attachment of
extensors on
carpometacarpus

Attachment of articu-
lar ligaments on
carpometacarpus

Fig. 2. Curve suggesting the relation of Parapavo (3) to the living Pavo (1)
and Agriocharis (2). e.g., In the character of its hypotarsus, Parapavo is more
remote from Agriocharis than is Pavo, in the nature of the spur, it is intermed-
iate but approaches closely to Agriocharis, in elevation of the spur it is again
intermediate but closely approximates Pavo, ete. Values approximated only.

are no differences between the birds as known by the tibiotarsus. Adult
specimens of both sexes yield the following measurements :

TABLE OF MEASUREMENTS OF THE TIBIOTARSUS

P. cristatus M. ocellatus P. californicus
Male Male Female Male Female
Mortal Len eth esses secrete seca eceatscseesevsece 197.7 mm. 187. 170. 205. 172.
Least transverse diameter shaft ...... 8.5 9; Shi 11.5 8.
Transverse diameter through head 10.4 19.3 19.8 23. 18.
Transvere diameter through foot.... 18. Ws 17.5 20, 16.8

Femur.—Several points of difference are to be noted on comparing
the femur in the living peacock and the ocellated turkey. Proportions
are again reversed and Pavo is found to be the stouter. The stoutness
may however be due to a greater degree of pneumaticity. Several

94 University of California Publications in Geology [ VoL. 9

pneumatic foramina appear upon the anterior face of the trochanter
and the whole bone shows a degree of translucence not visible in
Meleagris. The disposal of the intermuscular lines on both anterior
and posterior faces of the femur produces different patterns in the two
species, although the difference is hard to define. In its lack of
pneumatic foramina and in the pattern of its intermuscular lines the
fossil species resembles M. ocellatus more than it does P. cristatus.

Humerus.—A proper comparison of the humerus in the Recent
Pavo and Meleagris is hardly possible, owing to the fact that this bone
in the only available specimen of peacock is either immature or path-
ological. The posterior limb bears every stamp of complete maturity
but the humerus shows the rough, striated surface, the poorly calcified
articulations, and the indistinct foramina and muscle scars of a
juvenal bird. The only basis of comparison remaining is the general
outline, which may not be normal and probably is decidedly abnormal.
The indications are that Pavo has a longer, straighter, and somewhat
weaker humerus than Meleagris has. The humerus of Pavo cali-
fornicus is decidedly more like that of Meleagris than like the one
specimen of Pavo cristatus when the adult bone is considered. When,
however, a jJuvenal specimen of the extinct species is taken for com-
parison, the resemblance les decidedly with Pavo.

Coracoid.—This bone in Pavo cristatus 1s shorter than in the female
Meleagris ocellatus. The head of the bone is less abruptly bent over,
the articulation of the scapula is less perfectly defined, and the inter-
muscular nes less pronounced. How much of this difference is due
to slow maturing of the pectoral arch and limbs it is impossible to
state. The only available coracoid of P. californicus which is in per-
fect condition shows a position intermediate with respect to the two
Recent species under discussion. The bone as a whole is much larger
than in the female Meleagris, the scapular sear is like Meleagris, the
flexure of the head is ike Pavo, the intermuscular lines show a pattern
intermediate between the two.

Carpometacarpus.—In Pavo cristatus this composite bone is long
and relatively slender as compared with Meleagris ocellatus. The
osseous tubercle which passes from the fused digits 2 and 3 toward the
ulnar side of the metacarpus is less developed and is placed nearer the
proximal extremity of the interdigital space. The process to which
the tendon of the extensor metacarpi radialis longior is attached. is
longer but more slender. The attachments of the articular ligaments
also differ in detail of pattern.

1916] Miller: Review of Pavo Californicus 95

In general proportions of the carpometacarpus, and in the nature
and position of the interdigital tubercle, the fossil species occupies an
intermediate position. In other respects this segment shows its closest
affinities to he with Pavo.

CONCLUSIONS

It will be seen from this careful serutiny of all the available
material, both Recent and fossil, that the original conclusion referring
the Rancho La Brea species to the genus Pavo was not without justi-
fication. Removal of the species from the genus Pavo and its reference
to the genus Meleagris would be an arbitrary step prompted simply
by the fact that Pavo is at present foreign to the Americas. Is this a
sufficient reason for such step?

If Marsh* be correct in his determination of Meleagris antiquus,
the genus Meleagris is one of long standing in the Americas. This
Oligocene species is based on the distal end of the humerus of a ‘‘large
gallinaceous bird approaching in size the wild turkey and probably of
the same group.’’ It was contemporaneous with Oreodon in certain
lake deposits of Oligocene age east of the Rockies. The specimen was
said to agree in the main with Meleagris gallopavo, but to lack the
broad longitudinal ridge on the inner surface of the distal end opposite
the radial condyle, also to lack the abrupt termination of the ulnar
condyle at its outer superior border. The specimen was not figured
and there is nothing in the brief description which will place the
species in Meleagris rather than in Pavo. The only other meleagrines
known from America are M. celer Marsh and M. superba Cope from
the Pleistocene of New Jersey. There is no apparent reason for con-
sidering the differentiation of Pavo from Meleagris as running back
to Oligocene time nor for denying the presence of Pavo in the New
World up until Recent time. Still less is there reason for ignoring the
possible intermigration of Old and New World phasianids. The dis-
tinction by ornithologists between Pavo and Meleagris is based largely
upon external characters.

Osteologically Meleagris ocellatus is almost as near to Pavo as it
is to Meleagris gallopavo. Various authors have commented on the
impropriety of using a common generic name for the two American
turkeys, Chapman stating his attitude as follows: ‘‘The differences

4 Marsh, O. C., Am, Journ. Sei., vol. 2, Aug., 1871.
5 Chapman, F., M., Bull. Am. Mus. Nat. Hist., vol. 8, art. 18, pp. 271-290, 1896.

96 Unwersity of Califorma Publications in Geology [ Vou. 9

in the form and the distribution of the warty excrescences of the head
and neck, and in the character of the erectile appendages of the fore-
head, the more highly graduated tail and more rounded retrices, the
absence of beard in the male and presence of rudimentary spurs in
the female are all characters which entitle ocelletus to generic dis-
tinction, and I would suggest, therefore, that it be placed in a new
genus for which I propose the name Agriocharis.’’®

The superficial characters of the ocellated turkey are such as to
give it the local Spanish name of ‘‘Pavo de Yucatan.’’ The ocellated
feathers in certain portions of the tail constitute a character com-
parable to, though not identical with the similar appearance in Pavo—
a character which is hard to attribute to convergent evolution. This
superficial resemblance, combining with those seen in the skeletons,
indicates a close relationship between the New and the Old world
phasianids. The fossil species from the asphalt is, in the combination
of its osteological characters, intermediate between the Yucatan and
the oriental birds, which are separated at present by subfamily dis-
tinction. It would seem imperative therefore to establish generic dis-
tinction for the Pleistocene bird. For this genus the name Parapavo
is proposed. In a study of the phylogeny of the Phasianidae, a most
logical place to search for intermediates between phasianines and
meleagrines would be the Pacific Coast of North America. This search
has been rewarded, and furthermore Chapman’s conclusion that the
of a former much wider range finds support in the occurrence at
Rancho La Brea of its Pleistocene relative, Parapavo californicus.

6 The writer is indebted to Dr. C. W. Richmond for a note on the priority of
Agriocharis over Eumeleagris, a name proposed by Dr. Coues.

Transmitted August 15, 1916.

eS es
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1
2
3
4
5.
6

7. A Review of the Species Pavo californicus, by Loye Holmes
8. The Qw! Remains from Rancho lua Brea, by Loye Holmes Miller .....
9. Two Vulturid Raptors from the Pleistocene of Rancho La Brea, by L
501s sine eR MenIaE Coen gl: SRE EMM ISDE ees ee ORE ;
10. Notes on Capromeryx Material from the Pleistocene of Rancho La Brea, by
Chandler 1.2. RU EE a ae ee .
11, A Study of the Skull and Dentition of Bison antiquus Leidy, with Special 5
to Material from the Pacific Coast, by Asa C. Chandler _.................
12. Fauna] Studies in the Cretaceous’ of the Santa Ana Mountains of
fornia, by Harl Leroy Packard (827) 2 22 ose eee
(13. Tertiary "Vertebrate Fauna from the Cedar Mountain Region of Western 1
by ‘John; ©: Merriam. i200 720 eee ee Sees
14, Fauna from the Lower Pliocene at Jacalitos Creek and Waltham Canyon, :
County, California, by Jorgen Ch Norma dl 2.2 pepe nie spoke
9 ‘
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Issued January 18, 1916

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VOLUME 6.

. The Condor-like Vultures of Rancho La Brea, by Loye Holmes Miller! pene Spi Behe

. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in sabre |

Nevada, by John C. Merriam. Part I.—Geologie History...........c-ss-cscescenssctecenesancenee

. The Geology of the Sargent Oil Field, by William PF. Jones ...........2.-s-ccscsesssonnoeeceseenene

’ Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, +5 F

Loye }Holmes Miller) 222.025. .c0-.---1<-edacettceesact-nesseneseseenvaypn esenprennseeneasnee setae ae = ae

5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A. Reid

6. Note on a Gigantic Bear from the Pleistocene of Rancho La Brea, by John Cc.

Merriam.,

7. A Colleetion of Mammalian Remains from Tertiary Beds on the Mohave Desert,

by John C. Merriam.

Nos. 6 and 7 im OMe COVED, --_.02.222ehsincrcenynenecreps-areennth gensustene-oseemenerss meena en ae

8 The Stratigraphic and Faunal Relations of the Martinez Formation to the om ‘

and Tejon North of Mount Diablo, by Roy E. Dickerson ...:1.2...0.---sccecssesesseneees \ ic

9. Neocolemanite, a Variety of Colemanite, and Howlite from Lang, Los Angeles | nh

County, California, by Arthur 8. Hake) ooo0..c..0t.0-1cccspeccceonuannusde-genseesedeeeeen eee

10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor

11. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern

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12. A Series of Eagle Tarsi from the Pleistocene of Rancho La Brea, by Le

MM Or oe co eaten ccetlate ap nadine tse famanctec atten pa eet ee ee acacia nes ae a fee Be Sis

13. Notes on the Relakonships of the Marine Saurian Fauna Described from the riasie
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mo poe

Ke ag

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16, Avifauna of the Pleistocene Cave Deposits of California, by Tage Holm
17. A Fossil Beaver from the Kettleman Hills, California, by Louise Kalen
18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam .......
19. The Elastic-Rebound Theory of Earthquakes, by Harry mime R

VOLUME ?.

. The Minerals of Tonopah, Nevada, by Arthur §. Eakle ....
. Pseudostratification in Santa, Barbara County, California, by Gabres Bi

09 =

a S12: ee) SMe PINE Coane ene IBBMe em SUSUR beh Nad a BAe
3. Recent Discoveries of Carnivora in the Pleistocene of Rancho La Brea, by J
Merriam 2... 254. UB es
4. The Neocene Section at Kirker Pass on the North Side of icant Dia’
Toy (CUAL ci cecen ite h ena EE a eae tras cae a a ete
5 hey caatin to Avian Palaeontology from the Pacific Coast of Nortl

Loye Holmes Maitlor <2. :..e..-5c2tc-secces-syavestasepeeee uae ssseneesonee

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 8, pp. 97-104, 1 text figure Issued January 18, 1916

THE OWL REMAINS FROM RANCHO LA BREA

BY
LOYE HOLMES MILLER FANG.
CONTENTS

PAGE

Berni GiTgO CULC, trl Miipseaeee tse eeeeer sce ees. Sete Se cess zag et gets airs Sos eee eees 2 UE se pet eee rus Sate sese eng! iets eee core oi
TREC OLOMOLE SD CCLOS perce ccc eet sors te settee DCTs ere fe ac Ai Sen Sacer Aaa pe Ooo ulesete ee 99
Aluco pratincola (Bonaparte) -.........22-2:2c-cccecsececceseeeececeeeeeeeseeseeseeceeseeneseeseeeeeeees 99
Opusbasion @iinm aes). erscses ie ccenkeee eet een es a rte eee enoseeceeteond eee 100
Bubomvaromml ans: (Gmelin) ececc.ceenceecec-ce occ suse sectecs 2 ocee-ce cence eteeee-seeeees eeteeeeeeseeeneeee 100
IRIN) «iS Se re eS a ee, a 102
Npeobyto cumicularia (Molina) -.2.2..2..cceccc-cceceneoe--ccceceeeeeoseteee ce eveesceue-sececcceseeecsen 104

SS ILEUOAN AA YEN Te 7 a ec re 104

INTRODUCTION

These nocturnal birds of prey appear, for some reason, much less
commonly in the asphalt beds than do those generally distinguished
as diurnal hunters, the Accipitres. This difference is notable both in
point of numbers and in variety. Whereas the great group of hawks
and eagles makes up full fifty per cent of the whole mass of bird
material taken from these beds, the owls represent no more than five
per cent. Twelve species of accipitrines have thus far been deter-
mined from the mass, while many yet remain unidentified. On the
other hand, but six species of owls are to be distinguished in the same
collection. We thus have a preponderance of ten to one in numbers
and of more than two to one in species in favor of the diurnal birds
of prey.

At the present time we might expect to find, at most, sixteen
aceipitrines in the southern California region, while as many as eight
species of owls are recorded from the same locality, a ratio of two
to one. In point of numbers it would be difficult to make an
accurate estimate of the living population, though it would certainly

98 University of California Publications in Geology [ Vou. 9

not seem to be so large a ratio as is shown by the fossil remains.
Does the ratio displayed in the collection of remains represent the
true faunal relation of these two groups at the time of deposition?

Were we to assume that the proportion of owls to hawks at the
present time represents the true condition of affairs at the time the
asphalt deposits were forming, it would be necessary to concede that
owls were for some reason less positively attracted to the theatre of
action at Rancho La Brea than were the hawks and eagles. Does the
owl less often feed upon dead or disabled prey? Does it less com-
monly alight in hunting and therefore escape the asphalt trap?

During several years’ acquaintance with the Rancho La Brea
region, the present writer has been much interested to watch the
Recent outflows of crude oil for the operation of the trap as it is set
today. Conditions prevail there at the present time which must
approximate somewhat closely, except for magnitude, the conditions
in Pleistocene time. In the Recent outpourings of raw asphalt the fol-
lowing species of birds have been noted still in the flesh :

Individuals
Barn owl, Aluco pratincola (Bonaparte) ...........2...22:::c:seceseceeeeeeeeeeees 3
Night heron, Nycticorax nicticorax (Linnaeus) ..............2.-22---2--+---+- 2
Green heron, Butorides virescens (Linnaeus) .- 2
Meadow lark, Sturnella neglecta Audubon ...............22.....-2:.00000-0000--=- 2
Shore) Pind (met ermine) esesesec ers ea cee ee ne 1
Turtle dove, Zenaidura macroura (Linnaeus) .|........222....--220---22000---+ 1
iceom, Coltmba Wiig Womestie ees cee eae eee eee eee 1
Peregrine faleon, Falco peregrinus Tunstall -.........22.0....222.---222-----+- 1
Night hawk; (Chordevles, :Sy.. 2 cecst cote e ccc eee eee 1
Linnet, Carpodacus mexicanus (Miller) .....-...-....-2-.-------:e----0eee-e0000-"* 1

These observations, so far as they are of value, go to show that
owls are among the most common victims of the asphalt and hawks
among the least. Certainly it would seem that the region is not
unattractive to owls.

Dr. Joseph Grinnell, Director of the California Museum of Verte-
brate Zoology, in an informal conversation on the matter expressed an
opinion, the recording of which he has kindly permitted. In brief it is
this: Owls hunt by sound instead of by sight. The whole specialization
of the bird through enlargement of the auditory apparatus to receive
the slightest sound and the softening of the plumage to prevent con-
fusion by whirring flight, points to the dependence of the bird upon the
slightest noise made by the prey. Hence, unlike the hawk who hunts by

1916] Miller: Owl Remains from Rancho La Brea 99

sight, the owl would not be tempted to so great an extent by the asphalt
victim. This aspect of the question is probably a very important one,
although some evidence may be noted running counter to it. Captive
owls are fed quite as readily upon non-living food as are the hawks,
even when the food bears no optical resemblance to the natural prey.
Owls also will alight upon mouse-baited steel traps set for carnivores ;
thus we have the suggestion that sound is only one factor in the dis-
covery and selection of the prey and the supposed difference in the
earrion habit of the hawks and the owls is reduced materially as a
factor in the prime question.

Exposure of fresh asphalt was doubtless in more extensive masses
during the Pleistocene than at the present time, else it had been
impossible to entangle the large animals whose remains occur in these
beds. Such conditions would have increased the proportion of large
hawks and eagles in the catch and at the same time perhaps reduced
the number of small hawks and especially of owls, since in the larger
mass of asphalt, small prey captured during the day when the asphalt
was most plastic would have entirely disappeared before nightfall.
Under such circumstances the bait would be removed from the trap
before the twilight hunting-time of the owls arrived. It is a very
notable fact that the hawks and falcons are far outnumbered in the
asphalt collections by the much larger eagles. It is so hard to con-
cede a living fauna of such proportions that an effort to find some other
expanation is natural. While the number and variety of the eagles
was undoubtedly greater during this age of mammals, it seems prob-
able also that the larger size of the asphalt outpours and the consequent
rapid disappearance of the smaller raptor bait may have had some
influence upon the results and that the conclusions naturally drawn
from a study of the fossil remains would better be modified in regard
to the proportions of the various elements of the fauna.

RECORD OF SPECIES
ALUCO PRATINCOLA (Bonaparte)

This form is by far the most common of the entire group of Striges
in the Rancho La Brea deposits. The remains oceur at all depths
and embrace all characteristic parts of the skeleton so that very
accurate determination of the species is made possible. Careful study
of this series of specimens fails to bring to light any variation outside
that natural to the species as it lives in the region to-day.

100 University of California Publications in Geology [ VoL. 9

OTUS ASIO (Linnaeus)

There occurs in the collection thus far reviewed a single specimen
of the tarsometatarsus of this species. The specimen is perfect in its
preservation and when compared with the corresponding bone of the
living species of the region, Otus asio bendiret, is seen to accord with
it in every particular as perfectly as though taken from the same
individual. No other remains of the species have yet come to light.

BUBO VIRGINIANUS (Gmelin)

Aside from Otus, the genus Bubo is the least commonly represented
of all the strigine genera recorded from the asphalt. However, among
the fifty thousand or more specimens of fossil birds from these beds,
there occur a goodly series of the tarsometatarsus as well as the other
more characteristic bones of the limbs, thus affording material for a
fairly complete study of variation in the Pleistocene phase of this
great owl. When the problem was first attacked, with smaller series
at hand, it was found that variation was so extensive and so abruptly
discontinuous that specifie distinction seemed imperative. However,
after careful scrutiny of the equally extended series at the Museum
of History, Science, and Art at Los Angeles, and thus supplementing
the series in the University collections, curves were plotted which
showed practically uniform gradients for the grosser dimensions and
the ratios of dimensions. The Pleistocene Bubo was thus found to be,
like the Pleistocene Haliaétus, a form of very wide range of variation.
Like Haliaétus also, the series of asphalt specimens includes within
its limits two Recent geographic races, a southern smaller and a
northern larger race. Bubo virginanus pacificus of Southern Cali-
fornia grades up to the lower limits of the Pleistocene series, while
the larger B. v. saturatus is far surpassed by the larger specimens from
the asphalt.

The horned owls from Rancho La Brea would present a difficult
problem in classification for the systematic ornithologist who readily
distinguishes in size as well as in color between the geographic races
of Bubo virginianus. The fossil species is distinguished from the
Recent by a character not held in common, 1.e., great variability in a
fixed locality. Some students of geographic races have gone so far as
to assert that no fossil bird should be assigned to the same species as
a Recent form. In the absence of those external characters upon
which the ornithologist in large measure relies, and, in view of the

1916] 101

Fig. 1. Bubo virginianus. Tarsometatarsus. The line 1 represents total lengths
in a series of fifteen individuals, X 1. Line 2, broken line representing transverse
diameters of shaft in the same series in the same order, XK 1°. Line 3, transverse
diameters of shaft arranged in series, X 12. Line 4, ratios of diameter over length
arranged in series and graphically represented in millimeters as shown in this cut,
< 190,

102 University of California Publications in Geology [ Vou. 9

great variability displayed by the fossil phases of many birds, there
would seem to be some measure of propriety in such contention.

ASIO

When the study of the Rancho La Brea birds was first undertaken,
one of the most serious obstacles arising was the absence of comparative
material representing the Recent birds of America. The genus Asio as
found in North America today embraces two species, A. wilsonianus and
A. flammeus, both of quite extended range. There are now at hand
complete skeletons including the more characteristic ihmb bones of both
species so that a discussion of these parts may be safely undertaken.

Tarsometatarsus.—The osteological characters of the tarsometa-
tarsus appear identical in the two species, the only difference lying in
the proportions of the bone. The specimen of wilsonianus at hand is
a female, that of flammeus is of unknown sex. In the owls, as in the
diurnal raptors, the female is commonly much larger than the male,
with the bones reaching the maximum of length and stoutness. The
female wilsonianus has a tarsus much shorter than in the one specimen
of fammeus, yet in all other dimensions the former bone is the larger.
Assuming the unsexed flammeus to be a male bird, a female would
doubtless exceed it in length and thus accentuate the difference between
the species. Assuming the specimen to be a female, the difference is
still a very positive one. A. flammeus seems thus to be a form with a
long slender shank as compared with its nearest ally, the short-shanked
A. wilsonianus.

This difference of the tarsometatarsus is at least not incongruous
with the habits of the two birds. Asio flammeus is essentially a ground-
dwelling species. Its nest is on the ground; its hiding place by day
is the long grass of open country; its prey is sought in such places,
and after catching its prey the bird alights upon the ground to devour
its meal. The other species, in marked contrast, is a bird of the woods.
Although its prey may be sought in the open, its hiding place by day
is in the dense thickets along watercourses. In such places it builds
its nest, the male commonly hiding in the near vicinity. It seems
quite possible that the more ambulatory habit of Asio /lammeus is
here seen reflected in the structure of the lower lhmb.

In the asphalt beds typical tarsometatarsi of both species of Asio
are found. They seem to have hunted over common ground and to
have fallen to a common bait.

1916 | Miller: Owl Remains from Rancho La Brea 103

Tibiotarsus.—This segment of the limb shows a partial reversal of
characters of the two species as displayed by the tarsometatarsus—a
reversal which is liable to produce confusion. Corresponding bones
from the same individual discussed above show A. wilsonianus to have
the advantage in length, although the difference is less in proportion
than in case of the shank. The greater robustness of wilsonianus is
apparent and marked. Confusion might however arise between a
female of fammeus and a male of wilsonianus. Such a possibility is
illustrated by a tibiotarsus from the same section of the excavation
with other remains of both species of Asio. It is shorter and yet more
slender than thé unsexed specimen of flammeus, so the question of its
identity is a difficulty one to decide. Study of a series of Asio material
from the asphalt, together with the two Recent specimens, points to
the conclusion that the Recent specimen of A. flammeus is a female
and that the Recent specimen of A. wilsonianus is a fully adult bird,
though not the maximum in tibial length. <A single fossil specimen
appears slightly longer and less robust by an almost imperceptible
degree.

Humerus.—In sharp distinction to the posterior limb, the humerus
of Asio flammeus has the short, stout, proportions of a larger bird of
strong flight. The bones of the Recent specimens are almost identical
in length but the greater robustness in flammeus is recognizable at a
glance. The transverse and the sagittal diameters at all points give
the humerus of A. flammeus an appearance of much greater strength
of flight than is possessed by the associated A. wilsonianus—a_ con-
clusion quite in harmony with the fact that the former species occurs
unmodified over a large part of the globe and has been taken by deep-
water ships as much as eight hundred miles at sea.

ASIO WILSONIANUS (Lesson)
Found fairly commonly in the asphalt, represented by most of parts
of the skeleton.

ASIO FLAMMEUS (Pontoppidan)
Found associated with the last-named species and in about equal

numbers.

J04 University of California Publications in Geology [ VoL. 9

SPEOTYTO CUNICULARIA (Molina)

Next to Otus and Bubo this little owl is the least common of the
group in the beds at Rancho La Brea. It is hard to understand this
scarcity of Speotyto, except its most exclusively insectivorous habit be
the clue. The species is in large degree diurnal, thus missing the
smaller rodents to some extent and being less positively attracted to
the asphalt trap. It is at present even more an open country bird
than is the short-eared owl, Asio flammeus. The small size of the
species may have permitted the destruction of the remains where more
rugged forms have persisted.

The asphalt collections contain representatives of most of the limb
bones of S. cunicularia.

SUMMARY

There occur in the asphalt beds six species of owls. All are assign-
able to existing species, though at least one of them, Bubo virginianus,
displays an unusual degree of variability.

Transmitted August 15, 19165.

Biel ei je bs i!
and the Southern Sierra
‘of the Moniszoy Gores in Califomia, by Brvco Harta,
stocene Rodents of @alifornia. by muouise Nolo me tac: settee essere caceecscvemene-taenntutees
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Tertiary Mammal Beds of Stewart and Ione Valleys in West-Central Nevada, by
ci clion 12s) TSIGS fe (Ge sain IE APNE UL Saini. ate i ace ear NEU 30¢
Tertiary Echinoids from the San Pablo Group of Middle California, by William S.
SEs al NE bd IRATE OBIE apes A em Oa le ae SEN 10¢
An Occurrence of Mammalian Remains in a Pleistocene Lake Deposit at Astor
Pass, near Pyramid Lake, Nevada, by John ©. Merriam ....0.0.........sccscssscscesssesesesesesen 10¢
The Fauna of the San Pablo Group of Middle California, by Bruce L. Clark.............. 1.75

Index in press,

SW aneschistian, og Ee NC A SA | RCN ea 8:0, 91 MRI EES Nn

fy
2.

oan

10.

> Op

| New Bpediid of the Hipparied Group £ cific |
inces of North America, by John C, } peur bee
The Occurrence of Oligocene in the ontra Costa Hills
Brpee: My Claris, cages emperor
. The Epigene Profiles of the Desert, by son
. New Horses from the Miocene and Pliocene of California, b
Corals from the Cretaceous and Tertiary of California and
Dfomall apache ts TEA ee mee eae ee 1: See te Bim amen het oe
. Relations of the Invertebrate to the Vertebrate Faunal Zones of
Etchegoin Formations in the North egalinga bien 2" California,
Nomlandd , ..-2.---3c Reh ee 2 oe coc ee
. A Review of the Species Pave californicus, by Loye fivimes Miller
. The Ow! Remains from Rancho La Brea, by Loye Holmes Miller ............
. Two Vulturid Raptors from the Pleistoedie of Rancho La Brea, by
Miller’ vice e.g ee ee, wescsneomeencs
Notes on Capromeryx Material from the Pleistocene of Rancho La E
Chandler’)... p20 0 2 ee So. RR ESE Tee ee Pe |

ae
doh ¢

_ LOYE HOLMES MILLER

i

} : é % § ~ ro
i

| __ UNIVERSITY OF CALIFORNIA PRESS _
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VOLUME 6. ° : £
. The Condor-like Vultures of Rancho La Brea, by Loye Holmes Millex..2) oye
. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern
Nevada, by John C. Merriam. Part I.—Geologie ELAStOT Y~---ss---sseeesessnnneecontrenneecentnen
The Geology of the Sargent Oil Field, by William F. Jomes .......2.2-----csscosssseennecsneese=
. Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, OneeREy by j
Loye Holmes Miller -.tecs poo... ---sscceretcengencecenet2epbansoubeoabsnthasesqancessan dee Sea a ;
. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, “by ie A. Reid
Note on a Gigantie Bear from the Pleistocene of Rancho La Brea, by John C.
Merriam.
. A Collection of Mammalian Remains from Tertiary Bete on the Mohave Desert,
by John C. Merriam. ;
\ Nos, 6 and 7 in Om€ COVER 1... nec.nc succes tieeen-sdes/pe tenses: uae dscns eee ee tes
8. The Stratigraphie and Maunal Relations of the Martinez Formation to the Chieo
and Tejon North of Mount Diablo, by Roy E. Dickerson .......-.2.:-.-.c.-:-sssnenssnenoserrse
9. Neocolemanite, a Variety of Colemanite, and Howlite from Lang, Los Ampelest
County, California, by Arthur S, Bale ono... oes eecgonsecterenweenmmsr se tee=t=see tae eereee ;
10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor...
11. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Nortiveneea)

“I an oO pore

Nevada, by John C. Merriam. Part [l.—Vertebrate Faunas ..ccs.c.-ssssssssseeeenene
12. A Series of Hagle Tarsi from the Pleistocene of Rancho La Brea, by Loye ‘Holmes
Miller) 2.22. cigeescncencee-sesnbanvanenchteceoabecbarsseretecpserteMack sandsu-dad-aeete=aghe ie eeeeeee eee er

13. Notes on the Relationships of the Marine Saurian Fauna Described from Bias Triassic
of Spitzbergen by Wiman, by John C, Merriam. "2
14. Notes on the Dentition of Omphalosaurus, by J ohn C, Merriam and Harold Cc. . Bryant.

Nos. 13 and 14 im oe COVER, -.-.-.e.-- meee ecoesee ab to- al seenenenans eee eee =
15. Notes on the Later Cenozoic History of the Mohave Desert Region i in Southeastern
California, by Charles Laurence Bakker <.nce-ce-cce-nsence-tnnes-nonensnonscnstgessiscoacntoena fps St"

16, Avifauna of the Pleistocene Cave Deposits of Galifernie, by Loye Holmes Mill
17. A Fossil Beaver from the Kettlerhan Hills, California, by Louise Kellogg”
: 18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam .........
19. The Hlastic-Rebound Theory of Earthquakes, by Harry Fielding Rei

VOLUME 7.

1, The Minerals of Tonopah, Nevada, by Arthur S. Hakle ee

2. Pseudostratification in Santa Barbara County, California, by George Da
Dale cn wescisdecetencaespnccdu rete dob aemeecadgeen tna ahem mera ae

3. Recent Discoveries of Carnivora in the Pleistocene of b

Oy (Merriman aoe ee 2 eh tc ap dyes data che ieee ce ae

4. The Neocene Section at Kirker Pass on the North Side of Mount Diabl
Ta; | CRawhk 2 ioc ke he te cle RL ee ee

5. Contributions to Avian Palaeontology from the Pacifi or
Loye Holmes’ Miller 0.23300 Ree eB ee

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 9, pp. 105-109, 3 text figures Issued March 10, 1916

TWO VULTURID RAPTORS FROM THE
PLEISTOCENE OF RANCHO LA BREA

BY

LOYE HOLMES MILLER

CONTENTS
PAGE
BTBTOG EATS GLU GC 1a eee cea eRe ree Nena ee NE ce a a NO ous Sate nas Senses atesdveeeeiaesuveee 105
ID ES Crip clOMMOL 1S PCCLOS ee oe: eee s ae cece se tecues oe ecteere caper eee ae tc ces ee secu sete euecen toc edocs ecco sueee 106
Neophrontops americanus, n. gen and SD. .......--2:---:c--eceeeeceeeceeeeececeeeceeeceeeeeseees 106
Neogyps errans, n. gen and SDP. .....22..2:.2sccsceceseceeeceeeeeeeeeeeeeeeees Posner One oh eee 108
INTRODUCTION

Those decidedly degenerate faleoniforms which are classed in the
old-world family Vulturidae occupy the same bionomie position within
their realm as is filled, in the new world, by the Cathartiformes and
the aberrant Polyborinae. An aggressively rapacious habit has, in the
vulturids, given place to the more passive manner of the earrion feeder
—a change that has its anatomic reflection, to some extent, in the beak
but most positively in the foot. This latter member practically ceases
its function as offensive armament and loses also in large measure its
power as a prehensile organ. The cannon bone of these passive faleconi-
forms may then be very properly expected to show interesting modi-
fications of the raptorial type. Such is certainly the case.

The tarsometatarsus of vulturids is characterized by weak contours
throughout. The anterior aspect displays but slight excavation in its
proximal region. Passing down the shaft and forming the antero-
external contour of the bone is a ridge which, in the active raptors,
is sharp and high. In vulturids this ridge is much mollified—a con-

106 University of California Publications in Geology [ VoL. 9

dition reaching its extreme manifestation in Neophron. The distal
trochleae are weak and come to he more nearly in the same right and
left plane instead of forming that strongly marked arch seen in birds
with prehensile feet, such as hawks and owls. The posterior face of
the shaft is less deeply excavated for the flexor tendons to the toes.
All these are characters indicative of reduction of prehensile power
in the foot. They are characters more or less noticeable in all vulturids
and they indicate roughly the degree of degeneracy from a more
aggressively raptorial type. Neophron, which is set off by some
writers from other vulturids, as constituting a distinct family, is
generally conceded to represent the extreme of this degeneracy and
it has the evidence of this degeneracy most indelibly stamped upon
the tarsometatarsus. Mainly because of the characters of this bone, the
Rancho La Brea species have been placed in new genera of these weak-
footed raptors, although in the case of Neophrontops other bones of
the body less characteristic than the tarsometatarsus correspond with
those of the old-world Neophron.

NEOPHRONTOPS AMERICANUS, n. gen. and sp.

Type specimen no. 22402, Univ. Calif. Col. Vert. Palae. From the asphalt
deposits of Rancho La Brea.

Tarsometatarsus.—The type is a perfect specimen, as well preserved
as though freshly macerated from the flesh. The ossification and the
distinctness of intermuscular lines indicate an individual of advanced
age. Other members of the series have smoother contours. The speci-
men of Neophron ginginianus available for comparison appears from
characters of the surface to be a slightly sub-adult bird. In general
proportions the two bones are almost identical, the ratio of shaft
diameter to length being .072 in Neophrontops and .0O77 in Neophron.
When viewed from in front, the asphalt specimen is seen to have less
pronounced excavation about the papilla of the tibialis anticus. That
papilla is thus more prominent and is placed higher on the shaft. The
anterior openings of the proximal foramina are closer together. The
antero-external contour of the shaft is a little more prominent, as is
also the intermuscular line running from the papilla of the tibialis
anticus down the front of the shaft. These last two characters may
well be due to age in the individual. Distally the shaft widens more
gradually into the foot and the trochleae are narrower and weaker.
The trochleae are more nearly on the same level.

1916] Miller: Vulturid Raptors from Rancho La Brea 107

In the hypotarsal region, Neophrontops is seen to have the hypo-
tarsal ridges more prominent, closer together, and without an incipient
third ridge between. The hypotarsus is set off more abruptly from

Fig. 1. Neophrontops americanus, n. gen. and sp. Natural size. a, Tarso-

metatarsus, anterior aspect. No. 22402. b, Tibiotarsus, anterior aspect. No.
22403.

Fig. 2. Neogyps errans, n.gen. and sp. Natural size. Tarsometatarsus,
anterior aspect. No. 22401.

the shaft below; the bone is more excavated so that parts of the
proximal end are appreciably thinner than in Neophron. The plantar
tendons occupy a deeper groove along the posterior face of the shaft.

108 University of California Publications in Geology [ Vou. 9

Tibiotarsus, eotype no. 22403, Univ. Calif. Col. Vert. Palae—The
tibiotarsus of the asphalt species is almost absolutely identical with
that of Neophron except that the shaft is slightly more slender and
the cnemial crest more prominent. The tunnel under the osseous
supratendinal bridge is similarly small and quite in keeping with the
weakness of the flexor tendons. The furrow leading to this tunnel
is almost obsolete, more so even than in the American Cathartes. The
intercotylar depression is practically identical with that of Neophron.
On the inner face of the inner condyle occurs a rugosity marking the
attachment of articular igaments. This rugosity is raised to a tubercle
in the active raptors, is less in Neophron and is least in Neophrontops.
Seen from the proximal end the two bones show an identical pattern.
From the rear the same holds true.

Humerus.—This bone in the fossil species is practically identical
with that of the Recent Neophron. Size, curvature, condyles, muscle
sears are almost as nearly alike in the two bones as though they had
been taken from the same individual. Certainly no tangible difference
is noticeable to the writer.

Judging from the remains thus far identified, Neophrontops
americanus must have been a vulture of about the same size and build
as Neophron ginginianus. The habits in feeding must also have been
fully as far removed from the truly rapacious as in the ease of the
living bird.

The factor of error in referring the several segments here discussed
to the same species is reduced to a minimum by the close resemblance
of all the segments respectively to the corresponding parts of the
skeleton of Neophron and by the repeated occurrence of the various
segments together in the same section of the asphalt excavation.

NEOGYPS ERRANS, n. gen. and sp.

Type specimen no. 22401, Univ. valif. Col. Vert. Palae. From the asphalt beds
of Rancho La Brea

Tarsometatarsus.—Slightly smaller than the minimum of Aquila
chrysaétos, but general proportions much the same as in that species.
The contours much less rugged; papilla of the tibialis anticus more
rounded and knob-like and placed higher on the shaft; distal trochleae
and outer ridge of the hyptotarsus weaker than in Aquila.

Assignment of the genus Neogyps to the family Vulturidae is a
step which has been taken only after deliberation extending over a

1916] Miller: Vulturid Raptors from Rancho La Brea 109

period of years. During this time the problem has been taken up,
worked out, and then laid aside many times. During each interval,
many specimens of the tarsometatarsus of Pleistocene eagles have been
examined, amounting in all to some thousands. In each case the same
conclusion has been reached, i.e., that the tarsometatarsus of Neogyps,
instantly recognizable among many specimens of varied species, pre-
sents a markedly vulturid aspect. Only after such mature considera-
tion, strengthened by the occurrence of another vulturid, Neophron-
tops, in the same horizon, is the final and constant conclusion
announced. Neogyps is either a true vulturid or else an approximation
to that group due to convergent modification.

The general impression made by the tarsometatarsus is of a stockily
built bird with a general resemblance to Gypaétus, though less in size
than Gypaétus barbatus. With the exception of the immediate region
of the anterior openings of the proximal foramina, the contours of
the bone are less rugged than in Gypaétus; the antero-external angle
of the shaft is less sharp; the trochleae are less distinctly set off from
the shaft and are less profoundly grooved; the outer hypotarsal ridge
is less developed. All these are characters which, in general, dis-
tinguish the vulturids from the more predaceous raptores, evidences
of degeneracy wherein Neogyps seems to have exceeded Gypaétus
barbatus.

TABLE OF MEASUREMENTS OF A SERIES OF FOURTEEN SPECIMENS OF THE
TARSOMETATARSUS OF NEOGYPS ERRANS

Type Average
Length, intercotylar tuberosity to extreme convexity of
MAG dhestnochle as Hitcsccvtec.Sc.sacssscetee=ssst2scstucsscctasesussocarscosastodees souscs 88.0mm. 87.8
Transverse diameter of head .................----.-:--0:-scsee-sceceeseeeenseeeseeees 19.6 19.6
Transverse diameter through trochleae ..........2...2.....22:::21e-20ee0--+ 22.6 22.4
Intercotylar tuberosity to center of papilla of tibialis anticus 20. 20.1
Ratio of power arm to resistanGe arm .......2..2..2.22.2.22.-2eeeeeee eee 22.6% 22.8%

Transmitted August 15, 1918.

? oy and Binictine of the Western El Paso Range and the Southern Sierra

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Tapir Remains from Late Cenozoic Beds of the Pacifie Coast Region, by John C.

TOES TST) aS A te ES aS eS 5-year 10c

The Monterey Series in California, by George Davis Louderback ...........---..----essssesse0 , 65e

‘Supplementary Notes on Fossil Sharks, by David Starr Jordan and Carl Hugh Beal... 10¢

Fauna of the Eocene at Marysville Buttes, California, by Roy E. Dickerson .......... 45¢

. Notes on Scutella norrisi and Scutaster aiden une by Robert wW. Pack ..........----2--0:0- 5e
4. The Skull and Dentition of a Camel from the Pleistocene of Rancho La Brea, by

% + Tioctasia (OR "SRG asa MI ao LEE ge Dean eS 20c

15. The Petrographice Designation of Alluvial Fan Formations, by Andrew C. Lawson.... 10¢
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o SIV Ire raTeNeN ELIE en et tack an Ue, ance seen ated nacneonhnny etn eaaatstyestnaninsdsant des Snsenate penencusnidesapteasnae 15¢
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24, eieistocene Beds at Manix in the Eastern Mohave Desert Region, by John P. |
r BES Wircatl il came cee gM 2 Zest conc cueet encod net cen hn centaeneety ones dyadercodcnuevecapupneteatpeed <noricuec-trasr serena 25e
25. The Problem of Aquatic Adaptation in the Carnivora, as Illustrated in the Oste-
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3. Teeth of a Cestraciont Shark from the Upper Triassic of Northern California, by
ey | Banal (Ch TBS 20 0 rae Ie ep ae Ee AE ae tae Ga 5e

; Bird Remains from the Pleistocene of San Pedro, California, by Loye Holmes Miller. 10e
5. Tertiary Echinoids of the Carrizo Creek Region in the Colorado Desert, by William

PRIN RIE ESAS VaR ees ree aR A es Mea cea ah ecencesoaecondsbebendbcustbederasnandeue OLS Me 20e
6. Fauna of the Martinez Eocene of California, by Roy Ernest Dickerson ....................-. $1.25
Description~ of New Species of Fossil Mollusca from the Later Marine Neocene of
Ly, ME OESRITEDS * [ogy Brahe Eid VP cas Ot eR ee nL ae 20¢
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he Agasoma-like Gastropods of the California Tertiary, by Walter A. English...... 15e
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e Occurrence of Tertiary Mammalian Remains in iba aise sete Nevada, by John

(MUS STINET” 292 CO Tae Se Ap en QR RRO 2 ~10e
Remains of Land Mammals from Marine Tertiary Beds in the Tejon Hills, Cali- ~

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Index in press.

. New Species of the Hips Group fror i the
inees of North America, by John C. Merriam ..................
. The Occurrence of Oligocene in the Contra Costa Hills of
Brecet Ty. Clams 02.222. sccscnenetetee ean conse poh Sie ee Ee
The Epigene Profiles of the Desert, by Andrew O. Lawson -...esesese-s
. New Horses from the Miocene and Pliocene of © John
. Corals from the Cretaceous and Tertiary of Galifornia and nek
BA) 11 BE: 11: Sap NERS ENS. RMR OMI NN So eM IR OE ee
. Relations of the Invertebrate to the Vertebiate Faunal Zoues of
Etchegoin Formations in the North Coalinga Region, California, by
s Nowland 2s. .oi2 aiecenac) gen pe a REESE NS
. A Review of the Species Pavo californicus, by Loye Holmes Miller =...
. The Ow! Remains from Rancho La Brea, by Loye Holmes Miller ....
. Two Vulturid Raptors from the Pleistocene of Rancho La Brea, by
Mill)r*: ...0.. 8. gg ta... ee RR a ne 2
10. Notes on Capromeryx Material irom the Pleistocene of Rancho La Pere,
Chan@ler 72.1... fe es. Soa poe wntoce ecg a a
11. A Study of the Skull and Dentition of Bison antiquus Leidy, with Special
to Material from the Pacific Coast, by Asa ©, Chandler
12. Faunal Studies in the Cretaceous of the Sania Ana Mountat
fornia, by Harl Leroy. Packard” 252022. 2... eee ee
13. Tertiary Vertebrate Fauna from the Cedar Mountain Region of Western
by Jolin: C. Merriam. e025!) eee ee
14. oe from the Lower Pliocene at Jacalitos Creek and Waltham Canyon
County, California, by Jorgen O. Nomland 2.0... ecc-cecec--ecnerennerenerenes

ro

Oo Rw DO

©o-

\

a4

og

ON CAPROMERYX MATERIAL FROM >

_ BY

‘

ASA C. CHANDLER

-

=)

dANSL F016 bs

Mationat mall

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. The Condor-like Vultures of Rancho La Brea, by Loye Holmes Miller. pee. ep
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. Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, “tr,

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The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A, Rei
Note on a Gigantic Bear from the Pleistocene of Rancho La at = John C
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2 oo RY pe

by John C. Merriam.

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10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Tayl
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. Recent Discoveries of Carnivora in the Pleistocene of Roney La sais
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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 9, No. 10, pp. 111-120, 8 text figures Issued January 18, 1916

NOTES ON CAPROMERYX MATERIAL FROM
THE PLEISTOCENE OF RANCHO LA BREA

BY
ASA C. CHANDLER

CONTENTS
PAGE
JUANES CONG LCE CR ENO 6 el a eee A ee eR eT 111
Skull and Horn-core ..........--.00.--...22-22 ees = PIU RR Ps ADDS PERE NOE PPO OI 112
Sai Smear Gael) Orr tlib] Omg eee eases eee ss eee eae eS seat cen eens 114
AVJSTAG eo Tale maT) Cus Rilo Sse eee sere cones 2 one Oe cee ee eee eed 117
ANTON OS) cep 8 Sa ae Lo el ey re a EE Oe OS RRO ES 118
Mishima LEO WANES} aS ge rn nn Ne 5 EP 118
INTRODUCTION

Since the description of Capromeryx minor Taylor was published
in 1911! from a number of fragments found in the Rancho La Brea
beds, there has been a considerable accumulation of material referable
to this species. A study of these specimens brings out a number of
interesting points regarding the structure of this animal. Some of
these points have a direct bearing on the relationships of Capromeryr.
With the material now at hand, a very fair estimate of the characters
of the animal may be made.

As was pointed out by Taylor, Capromeryx is a form of especial
interest, since so few antelope-hke animals have been obtained in
North America, and as yet the relationships of those which have been
found are very imperfectly known, so that every addition to our
knowledge of any antelope-like form is important.

The material now at hand includes the majority of the hmb and
foot bones, lower jaws with complete dentition of both milk and per-
manent sets, fragments of the upper jaw, two pieces of skulls, both
including the region of the horn-core, and several vertebrae.

1 Univ. Calif, Publ., Bull. Dept. Geol., vol. 6, pp. 191-197, 1911.

iz University of California Publications in Geology [ Vou. 9

In the preparation of this paper, the author has been very deeply
indebted to Professor J. C. Merriam for his kind assistance and co-
operation, and to Mr. Frank S. Daggett of the Museum of History,
Science and Art in Los Angeles, for his generous loan of material
from that museum.

SKULL AND HORN-CORE

Although a considerable quantity of limb bones have been found
belonging to this species, there have been discovered up to the present
time only a few fragments of skull, two of which include the region
of the horn-core and dorsal part of the orbit. Two pieces represent
upper Jaws with M? and M? in place in one specimen, and three milk
molars in another.

Specimen no. 21445 is a small portion of the dorsal part of the
forehead, from the nasal bones to the occipital ridge, and including
the dorsal rim of the orbit on the right side, but broken off at
the region of the frontal foramen on the left side. This interesting
specimen shows the same general contour lines as does Antilocapra.
It has a prominent orbit, the high arch of the forehead comes between
the orbits, instead of behind them as in the deer, and there is a con-
siderable concavity between the anterior borders of the orbits. Whether
the nasal bones arched up as prominently as in Antilocapra is a matter
of conjecture, but the remarkable similarity of the lines of the skull
immediately behind the nasal region to the corresponding parts in
Antilocapra makes it seem highly probable that Capromeryx had a
similar high-arched nasal region. The frontal foramen has a single
opening instead of a double one, and hes in a more marked groove
than in Antilocapra, in this feature approaching more nearly the deer.
There is also, in this species, a shallow pit lying posterior to the frontal
foramen, and just external to this a very minute tubercle which, by
analogy with Antilocapra, represent a rudimentary horn-core of a
female animal, although in Antilocapra it is considerably more con-
spicuous.

Specimen no. 49 of the Museum of History, Science and Art of
Los Angeles consists of the right side of the parietal and frontal bones
with the horn-core and about one-half of the orbit. In the general
characters of the skull this specimen agrees perfectly with no. 21445,
except that the pit just medial to the horn-core is considerably deeper

and more marked.

1916]

Chandler: Notes on Capromeryxc 113

ACOA
1
A(t (

Figs. la to ld. Capromeryx minor Taylor.
right horn-core.

A portion of the eranium with the
Specimen no. 49, Museum of History, Science, and Art, Los
Angeles, natural size. From the Pleistocene of Rancho La Brea, California.

Fig. la, posterior view; fig. 1b, anterior view; fig. 1c, superior view; fig. 1d,
lateral view.

114 University of California Publications in Geology [ Vou. 9

The horn-core of this specimen represents one of the most remark-
able types yet discovered, and differs widely from that of any other
form, either living or extinct. Looking at it in side view it has the
appearance of a double horn growing from a single broad base (fig. 1d).
The larger posterior prong, which reaches to a height of 65 mm.
above the dorsal rim of the orbit, is more or less cylindrical, though
somewhat flattened on the anterior face, and tapers evenly from the
point of separation from the smaller anterior prong. The latter does
not have the usual appearance of a fork, but grows out parallel to the
larger prong from a common broad base about 15 mm. high, which
gives the impression of a growing together of the basal portion of two
horns rather than the broad base of a single horn which has two forks.
The anterior prong is not only shorter but of much smaller calibre
than the posterior prong. It is triangular in cross-section, having
a broad flat posterior face, the apex of the triangle pointing anteriorly
(fig. 1b). From the posterior view the anterior prong does not appear
at all (fig. la). Figure 1c shows the appearance of the horn-core look-
ing straight down at it from above, and makes clear the relation of
the two prongs to each other. From what sort of a horn-core this very
unusual type might have been derived cannot be suggested with any
reasonable assurance as yet. Its relation to the horn of Antilocapra
is also doubtful. While it may represent an entirely independent off-
shoot from a common ancestor, it may also be in the direct line of
descent of Antilocapra. In fact, the peculiar sword-like shape of the
horn-core of the pronghorn antelope can more easily be imagined to
have developed from the type of horn found in Capromeryx minor
than from any other known kind of horn-core, merely by a further
erowing together of the apposed faces of the two prongs. The form
of the horn sheath, with its long posterior and short anterior prong,
might be looked upon as suggesting an ancestral condition in which
the horn-core was also forked. There is no other known case in which
a simple horn-core possesses a forked sheath.

JAWS AND DENTITION
Specimen no. 20032 is a fragment of the right maxillary bone with
M* and M? in place. These teeth resemble their counterparts in
Antilocapra very closely, the only difference in form being in the
slightly better development of the outer styles. These teeth of
Capromeryx are almost exactly two-thirds the size of the correspond-
ing ones of Antilocapra.

1916] Chandler: Notes on Capromeryx 115

Figs. 2 to 4. Capromeryx minor Taylor. Jaws and dentition, natural size,
from the Pleistocene of Rancho La Brea, California.

Fig. 2. Left maxillary with milk dentition, from Museum of History, Science,
and Art, Los Angeles.

Figs. 8a and 3b. Right ramus of mandible with dentition, no. 20036, natural
size.

Fig. 4. Right ramus of mandible with milk premolars and M,, no. 19977,
natural size,

116 University of California Publications in Geology [ Vou. 9

A very interesting specimen, belonging to the Museum of History,
Science and Art of Los Angeles, is a portion of the left maxillary
bone with the three milk molars in postion (fig. 2). Dm? is consider-
ably worn, and no lakes are present. Dm* is also much worn, but there
is still present a fairly large posterior lake and a small anterior one
which is almost lost. Dm* is almost identical with permanent M1?
in form. The total length of the row of milk teeth is 21 mm. while
the premolar series in Antilocapra measures 28 mm. The length of
Dm‘ is 9mm., while that of the permanent M? is 10 m.

Since 1911, when Taylor’s description was written, enough lower
jaw material has been accumulated to give an aequaintanee with
practically all the teeth of the lower jaw of both milk and permanent
dentition, as well as with the general proportions of the jaw itself. In
general it may be said that the dentition, in both sets, strikingly
resembles that of the modern pronghorn, although there are a few
significant differences.

Dm.,, the first cheek-tooth of the lower jaw, is a narrower tooth
than the permanent P, of Antilocapra, and not as well developed,
and has a much shallower anterior open valley, though in general they
resemble each other.

Dm. and permanent P., resemble each other in that the anterior
valley is open on the inner side in both, but they differ in size, the
permanent tooth being shorter than the milk tooth, but broader and
heavier. P., of Capromeryx is very much simpler than the same tooth
in Antilocapra, the lobe posterior to the open inner valley being
unmodified in the former, but furnished with an enclosed lake in the
latter.

Dm, is a three-lobed tooth, very similar to Dm, of Antilocapra,
but relatively a little larger. Permanent P, however, which replaces
it, differs very considerably, not only from its own predecessor, but
from its counterpart in Antilocapra as well. To a striking extent,
it resembles permanent P, of Antilocapra, having the anterior valley
wide open on the inner side, and a well-marked outer posterior groove
as well as one on the posterior margin of the tooth. The last is not
deep, and is therefore noticeable only on very slightly worn teeth.

Permanent M, and M, are so similar to those of Antilocapra that
no points of difference in them can be picked out, so far as form is
concerned. M., however, is more primitive than M, of Antilocapra
in the inferior development of the fourth lobe or heel. While in the
modern species this tooth normally has a very distinct fourth lobe,

1916] Chandler: Notes on Capromeryx Aly

in Capromeryx this is only suggested by a slight elongation of the
third lobe. It is interesting to note that in an abnormal specimen
of Antilocapra americana (U. C. M. V. Z. no. 8299) the last lobe is
missing, the condition being identical with that found in Capromery-r.
M, of the latter is directly intermediate between Antilocapra and the
older Merycodus, since in the latter the third lobe is not only not
divided but is considerably smaller than either of the other lobes.

The degree of hypsodonty of both milk and permanent teeth is
comparable with that in Antilocapra, being far in advance of Meryc-
odus in this respect, as has previously been pointed out by Tavlor for
the milk dentition. As is indicated below, the lower jaw is relatively
shorter than that of the pronghorn, and while the lower row of cheek-
teeth is longer in Capromeryx relative to the length of the jaw, it is
shorter relative to the size of the body, which in most measurements
averages about two-thirds the size of Antilocapra.

The mandible of Capromeryx minor differs considerably from
Antilocapra in its proportions. The depth of the jaw is relatively
much greater in Capromeryx; the vertical ramus stands more nearly
at right angles to the horizontal ramus; the diastema between cheek-
teeth and incisors is almost equal to the length of the tooth-row in an
Antilocapra in which the permanent dentition is all functional but
slightly worn, while in a specimen of Capromery. of similar age it
is less than two-thirds as great; the anterior dental foramen is much
nearer the tip of the symphysis than to P, in Antilocapra, while in
Capromeryx it is about half-way between, on account of the shortening
of the jaw between the foramen and the cheek-teeth. To sum up, it
may be said that the jaw of the diminutive extinct antelope is rela-
tively shorter and heavier than that of its modern relative, and that
this shortness of the jaw very probably was correlated with a shorter
snout.

VERTEBRAE AND RIBS

Axis.—The axis very much resembles that of Antilocapra, but has
a deeper and thinner ventral ridge, and a relatively smaller centrum.
The transverse processes do not reach as far posteriorly as the ventral
tip of the centrum, whereas in Antilocapra they reach very consider-
ably beyond. The vertebraterial canal is relatively very large.

Thoracic vertebrae——A fragment of what is probably the eighth
thoracic vertebra has been found. It has a relatively long centrum
and large demifacets for rib articulations.

118 University of California Publications in Geology [ Vou. 9

Lumbar vertebrae.—Several fragments of lumbar vertebrae have
been found which are probably referable to this species. No. 21446
is a perfect lumbar vertebra, probably the fifth, which differs from
that of Antilocapra in the shape of the neural spine, which is con-
siderably wider along its dorsal edge than in the middle of its length,
and in the deep incurving of the contour in lateral view on the pos-
terior side of the neural spine. The centrum in this and another
similar specimen is of slightly different shape from that in the prong-
horn, being relatively broader and not so deep, enclosing a larger
neural canal.

Ribs.—No well preserved ribs referable to Capromeryx have yet
been found, only a few fragments being at hand, from which no definite
comparisons may be made.

ARCHES

Scapula.—Several broken pieces of scapulae show that while in
general proportions, shape, ete., there was no striking difference between
Capromerys and Antilocapra, the former was a little more like the
latter than lke Ilingoceros. The anterior edge of the articular surface
of the glenoid cavity is well separated from the coracoid process. The
lateral prominence of the coracoid process is poorly developed. Viewed
from its proximal end, the outer border of the glenoid cavity forms
an even curve with the coracoid process as it does in Antilocapra,
Tlingoceros differing from both in this respect. The anterior border
of the glenoid cavity is produced into a sharp ventrally projecting
point. The scapula of Capromeryx is about five-eighths the size of
that in Antilocapra.

Pelvis—A few fragments of pelvis show no important points of
difference between the existing American antelope and the diminutive .
extinct species. The acetabulum is relatively slightly smaller in the
fossil species.

LIMB BONES

Specimens of a considerable number of the limb bones of this
species have been found. and show that, as was suggested by Taylor,
it was a form with long, light limbs, comparable with those of the
pronghorn.

A few fragments of humeri have been found, but no femur. The
humerus is, if anything, slightly more slender than that of Antilocapra,
and very much the same in structure.

A complete radius and a number of fragments have been found.
The length and proportions relative to the rest of the skeleton are not

1916] Chandler: Notes on Capromeryx 119

appreciably different from the condition in the pronghorn. The groove
for the ulna on the posterior side is very conspicuous, and the proximal
articular surface is not so much expanded as in Antilocapra. No ulna
has yet been recovered. The tibia is considerably more slender than
is that of Antilocapra, and is a little more nearly circular in cross-
section than is that of the Recent species.

A large number of metapodials have been found, ineluding a
number of complete ones, the great majority, however, being from the
hind limb. In the anterior metapodials the groove on the anterior
face is very slight, in fact almost obsolete, but the posterior groove is
both broad and deep, much more conspicuous than in Antilocapra.
The posterior metapodials were fully described and figured by Taylor.”

A considerable number of well-preserved astragali and caleanei have
been found, although other ankle and wrist bones have not certainly
been identified.

The new series of astragali show that the specimen upon which
Taylor based his description was somewhat worn, and that this caused
him to draw some erroneous conclusions. The knob on the inner side
of the central dorsal fossa is fully as well developed as in Antilocapra,
and more so than in Ilingoceros. The groove on the dorso-proximal
articular surface is more pronounced than in Ilingoceros, and this
articular surface swings around ventrally farther than in Ilingoceros,
in both these respects approaching Antilocapra. The central dorsal
fossa is smaller and deeper than in either of the other genera mentioned.
Between the knob deseribed above and the anterior articular surface
there is no deep groove as there is in Antilocapra, this condition
agreeing with that in Jlingoceros. A further similarity to the latter is
shown in the contour of the distal end, where the trochlea is distinctly
rounded and the sides tend to become flattened as in the cervid type.
The proximal trochlea is narrower and deeper than in the other genera.
The projection on the inner proximo-ventral angle is nearer to that
of Antilocapra, while the whole distal half of the outer aspect, and
the groove into which the caleaneum fits on the ventral side are more
suggestive of [lingoceros.

The calcanei, some perfect specimens of which are at hand, tend
to corroborate the evidence given by the astragali, that Capromeryxr
is In some respects nearer to Jlingoceros, but in most characters ap-
proaches more closely to Antilocapra. The groove on the inner surface,
adjacent to the articulation with the cuboid, is very distinct, and has

2 Op. cil.

120 University of California Publications in Geology [ Vou. 9

approximately parallel sides. In Ilingoceros this groove does not widen
distally as much as in Antilocapra, and in both the latter forms the
groove is but slightly differentiated from the rest of the inner surface.
The surface interior to the articulation with the ventral side of the
astragalus is narrow and elongated, very different from Antilocapra,
this condition being due to the very marked sloping off of the promi-
nence bearing the articulation with the ventral side of the astragalus.
Ilingoceros is intermediate in this respect. The shape of the main
articular surface for the astragalus is similar to that of Antilocapra,
and unhke that of Ilingoceros. The articular surface for the cuboid
has not quite so much sigmoid curvature as has Ilingoceros but has
considerably more than Antilocapra. The notch in the side of the
articulation with the fibula is deeper and sharper than in either of
the other genera. There is a well-marked groove just above the articu-
lation with the cuboid which is very shallow in Ilingoceros and prac-
tically absent in Antilocapra.

A number of well-preserved proximal and middle phalanges cor-
roborate the evidence of the other limb bones, that this species was a
very light-lmbed form. The narrowness from the inner to the outer
side of the proximal phalanges as compared with the anteroposterior
diameter is striking. In both Ilingoceros and Antilocapra these dimen-
sions have a ration of 5 to 6 at the proximal end, while in Capromeryx
the ratio is 4 to 6. Another characteristic is the great amount of
tapering to the point of shortest anteroposterior diameters, the ratio
between the narrowest and widest diameters being in Capromeryx
1 to 1.76, in Antilocapra 1 to 1.60, and in Ilingoceros 1 to 1.36. A
single minute middle phalanx has the same characteristic compressed
appearance. The anterior surface just back of the distal articulating
surface comes to a distinct ridge instead of being broadly rounded.
This portion of the phalanx sags down so as to give a distinct dip in
the anterior contour. In these respects as well as in general form
this species is much nearer to Ilingoceros than to Antilocapra.

The toe bones were described and ffgured by Taylor® and as pointed
out by him, they are nearer to the form of the toe bones of Ilingoceros
than to any other forms at hand. They have a distinct ‘‘roman-nose’’
dorsal contour, which is characteristic of antelopes as contrasted with
deer. The dorsal convexity, as pointed out by Taylor, is not as marked
as in Antilocapra.

3 Op. cit.

Transmitted May, 1914.

Charles” aaa cicada Sn oe sone
from the Type Locality of ae ae Series in C rnia, by Bruce Martin.
cene Rodents of California, by Louise Kellogg. .....-....--:-2-csec-csceesceeeesceeseerecnee
pir Remains from Late Cenozoic Beds of the Pacifie Coast Region, by John C.
DIV a TRea AA peas oe ane Ue ELE acted tanng os tSuath anda eandaetaerane nar arercta=aatynecgneabr=
0. ‘The Monterey Series in California, by George Davis Louderback
11. Supplementary Notes on Fossil Sharks, by David Starr Jordan and Carl Hugh Beal ..

12, Fauna of the Eocene at Marysville Buttes, California, by Roy E. Dickerson .........-
F 13. Notes on Scutella norrisi and Seutaster Anderson by. Robert WeeRack Sen ea.
_ 14, The Skull and Dentition of a Camel from the Pleistocene of Rancho La Brea, by
i shri davza OP, SAIS} MEDS CE SO SA Ay nee nce Os Meee tN ae

15. The Petrographic Designation of Alluvial Fan Formations, by Andrew C. Lawson...
16. A Peculiar Horn or Antler from the Mohave Miocene of California, by John C. Mer-
Freer TERPS cee ae ese ek ee ae MES aoe oat dace naar ndenigeodt=ncwe-n samen cee ruareeaceoatonaeretpereratdaes
17. Nothrotherium and Megalonyx from the Pleistocene of Southern California, by

ri BSN ME TSIM SS) LOC ctr ec tere see eee eat e Me ses de teenUecdcnatastucnaenrecacsearectaavagenaee aerate
_ 18. Notes on the Canid Genus Tephrocyon, by John C. Merriam
_ 19. Vertebrate Fauna of the Orindan and Siestan Beds in Middle Colieornigs by John

ae MO PBIVCO IN IQ ease Neato sot pn ceandtetarenetasaanctanehadutesavasmanvas tuedarmtecoueeseedencesernnstatnaceceecacnane=cases
20. Recent Observations on the Mode of Accumulation of the Bicwiooae Bone Deposits
es, Gmivancho) lua Brea, iby, Repinald’ OH Stomer 2.:.- fio c-ct.:-ceecceeneesotease-necsnonasnvasnaedlscnntocneeeer
21. Preliminary Report on the Horses of Rancho La Brea, by John C. Merriam ............
22. New Anchitheriine Horses from the Tertiary of the Great Basin Area, by John C.
ie INTSRRET AIERY he ae A MN AS SSS te CU MT TR en 8 Ue
_ 23. New Protohippine Horses from Tertiary Beds on the Western Border of the Mohave
tae DE encom nymelOlmy Ga WCRI Seater ss West screcne sat .ocsenscsnenccemces cnsarcasostemncnnd=-osnennse etneene er eatar
| 24, Pleistocene Beds at Manix in the Eastern Mohave Desert Region, by John P.
~ TSU EIGIED ee actin BE epee eee aeRM RnR Be He es UR EE OP
25. The Problem of Aquatic Adaptation in the Carnivora, as Illustrated in the Oste-
; ology and Evolution of the Sea-Otter, by Walter P. Taylor ..........-..-.::-s:c:scesscessecese

. VOLUME 8.
1. Is the Boulder ‘‘Batholith’’ a Laccolith? A Problem in Ore-Genesis, by Andrew
SPAM OI Mr see aE cae eS are TE ocean levied acc asateye Soubcnccitendeeenonadiccbentnaguansaecsdbeane suet
2. Note on the-Faunal Zones ‘of the Tejon Group, by Roy E. Dickerson ........-.........----»
_ 38. Teeth of a Cestraciont Shark from the Upper Triassie of Northern California, by
“= Teheanalial (CP Teves Zaviat recha. Sale sey cAMP

_ 4, Bird Remains from the Pleistocene of San Pedro, California, by Loye Holmes Miller.
; g ne Hehinoids of the Carrizo Creek Region in the Colorado Desert, by William
ie SIR od RCS RE SS Ec OR Re ne RO
_ 6, Fauna of the Martinez Eocene of California, by Roy Ernest Dickerson ..................----

7%. Description~ of New Species of Fossil Mollusca from the Later Marine Neocene of
RC ucouiia- aby parucen Martin .f 20 el a ne
8. The Fernando Group near Newhall, California, by Walter A. English
s aa Deposition in and near Intrusive Rocks by Meteoric Waters, by Andrew C.

BIER Is eo RE ROE
The Agasoma-like Gastropods of the California Tertiary, by Walter A. English......
The Martinez and Tejon Hocene and Associated Formations of the Santa Ana

Beprlionmiminss: by iy. Wi; DICKOTSON 1.2250. A a oeeccteccceteccceccecacatedseneeuchastesrectecteenescualberctuaes
The Occurrence of Tertiary Mammalian Remains in Northeastern Nevada, by John
SNIPS RR ESA ee ee Ce he ee eR eR
emains of Land Mammals from Marine Tertiary Beds in the Tejon Hills, Cali-

DIM omy AION A Ca Mierrr ama see eh 8) ae) SP a eee
The Martinez Eocene and Associated formations at Rock Creek on the Western
_ Border of the Mohave Desert Area, by Roy EB. Dickerson -.......:s:.--ss1---sssescsecsseeconee
New Molluscan Species from the Martinez Eocene of Southern California, by Roy

Th. UDIECCTERTSSES Soya oe NO Se a: nN Op a Nt cM ORL Ee
A Proboscidean Tooth from the Truckee Beds of Western Nevada, by John P.

1a EIGHT Ga RO 2 MR cl oR cE eo Ce eA
ly 1. Notes on the Copper Ores at Ely, Nevada, by Alfred R. Whitman .............-..::::02000-
18. Skull and Dentition of the Mylodont Sloths of Rancho La Brea, by Chester Stock.
19, Tertiary Mammal Beds of Stewart and Ione Valleys in West-Central Nevada, by

ON A aed RI CO ee le A MRE RR oy SNe ee RN OS
21, An Occurrence of Mammalian Remains in a Pleistocene Lake Deposit at Astor
! Pass, near Pyramid Lake, Nevada, by John ©, Merriam .........-.s-cesessssessessessssesseteecee

, The Fauna of the San Pablo Group of Middle California, by Bruce L. Clark..............

Index in press.

John i Buwalda ri ERE Mee UNS Hea SE Sais SEI: 2 ea le a RR, eaeat AP OSIM EI :

,

1, New Species of the Hipp
-- inees of North America,
2 fas Occurrence of Onigped
y Bruce L. Clark .....-.0..0-- li
3. ‘the Epigene Profiles of the D
4, New Horses from the Miocen
5, Corals from the Cretaceous and Te
j Norman! 2h 7s Lee ee
6, Relations of the Invertebrate to
Etchegoin Formations in the |
Vie Noman .s0) 0/0) Dagens
7. A Review of the Species Pavo ifornicus, oye
8. The Ow] Remains from Rancho La Brea, by "hava Holmes
9, Two Vulturid Raptors from the Pleistocene of Rancho La Brea

10. Notes on Capromeryx Materia from
Chandler

Oe oi ee e% Eg |e er
7 + oe woes et ee Re ai ’
121-135, 12 text figures — Issued February 23, 1916 aa ap

> a ae

y
by vo
- ais
ins fer

STUDY OF THE SKULL AND DENTITION OF —

BISON ANTIQUUS LEIDY, WITH SPECIAL
__ REFERENCE TO MATERIAL FROM =

hae |) FHE PACIFIC COAST
Fa % £ e wit . ‘
F BY
ASA C. CHANDLER
: a Dey
a Ze
‘ x
B53
RL ens
wer instity

_ UNIVERSITY OF CALIFORNIA PRESS
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VOLUME 6.
1. The Condor-like Vultures of Rancho La Brea, by Loye Holmes Miller... sce
2. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern
Nevada, by John C. Merriam. Part I.—Geologie History......-...-.-ccccecesscsusmssesaneus ol
3, The Geology of the Sargent Oil Field, by William F. Jomes .......22.-...-cccssesessanenseunenee ty Fy
4. Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, ae by
Loye Holmes Maller .o.-..n.......-:tcsestnesessseseannenaceee:csoes sna dnedenneascsensatiensteaeae sea s
5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A, Reid
6. Note on a Gigantic Bear from the Pleistocene of Rancho La Brea, by Joha C.
Merriam,
7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Des
by John C. Merriam.
Nos, Gand 7 if ONG COVEN ... 220.2, 2.-cccevarugesesnoncnenspeesenpennranssihe-nankay=daeea=ta eee
8. The Stratigraphic and Faunal Relations of the Martinez Formation to the Chieo
and Tejon North of Mount Diablo, by Roy HE, Dickerson ........-...--s::ssnsstecensssees
f 9, Neccolemanite, a Variety of Colemanite, and Howlite from Lang, Los Angeles _
County, California, by Arthur S. Hake 00.000. occyccssoce-pancea-sas beeen eee
10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor... %
11. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern | u
Nevada, by John C. Merriam. Part I1—Vertebrate Faumas ......-.:cssssssss-on
12.. A Series of Eagle Tarsi from the Pleistocene of Rancho La Brea, by Loye fiolmes
_ Miller nv endbsupensniiisnennsteecadens nam Cancnaestenuine tent esi esedete ae esaepe Sah Bk she a ea Bc eee

of ha kswateay by Wiman, by John C. Merriam.
14, Notes on the Dentition of Omphalosaurus, by John C. Merriam and Harold C. Bae

Nos. 13 and 14: im ome COVER 2.2...) cei. cese- dent. ccesnevonanpensenns=narh <2 eee aaa eee
15. Notes on the Later Cenozoie History of the Mohave Desert Region in Southeastern
California, by~Charles Lawrence Bal erie... sdctetecrubeemenaecoe sararcosban she chee oe

16. Avifauna of the Pleistocene Cave Deposits of California, hy Loye Holmes Miller
17. A Fossil Beaver from the Kettleman Hills, California, by Louise Kellogg .....
18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam ......W...0.. esc sali
19. The Elastic-Rebound Theory of Earthquakes, by Harry Fielding Reid .......

VOLUME 7. _ :
1, The Minerals of Tonopah, Nevada, by Arthur S. Hakle ..........--.-sctecs-cenene
2. Pseudostratification in Santa Barbara County, California, by George Davis Louder-
Dake ooo die selseeds pac lapewatddanedtoanddcenpvasgua otk been ieanetge NaC Ina tee ea ante contesapnaccnmabl
. Recent Discoveries of Carnivora in the Pleistocene of Rancho La Brea, bs f
Merriam | 25... MI pee el ccs toes adiees Giaeen doe Bee eee oe Nat a
; 4, The Neocene Section at Kirker Pass on the North Side of Mount Diablo,
5

ww

Ta, Care tpn concept nechaee Spetednn colf vodbicnscbnupadauecsea vaplety eee CEE ae ee a Baa
. Contributions to Avian Palaeontology from the Pacific Coast of North 4
Leys Holmes Muller 5.2) 0.2-hcc ae eco ipdeia eet

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 9, No. 11, pp. 121-135, 12 text figures Issued February 23, 1916

A STUDY OF THE SKULL AND DENTITION OF
BISON ANTIQUUS LEIDY, WITH SPECIAL
REFERENCE TO MATERIAL FROM
THE PACIFIC COAST

BY

ASA C. CHANDLER

CONTENTS
PAGE
UOTaRCES OG RLU OE OO ee ea eee eee 121
Individual and Sexual Variation in Existing Species —.......0202222.0-2.---2----- 122
IB 1S On SOme Coin ae us): saxense seen secre eee eee cee ree eee eee 122
NESTS OM, OTL AS WS ees occa oe re ecco eee oe ee ec Seas re eee dade fos eee ceed ae ese renee ceanceee 124
General Account of Bison antiquus .....-......222...--222------:00--22eeceeeeeeeeeeeeeceeeeeeeeeeeeeeeeees 124
TET S (OTs Cea eee ee ee nO Eh ae ere a re ph gee eee aes wens 124
WeseniptronsotweNie ww: Material) seme: cscn nrc ckeee ra: eeeee veces. 2c0ory acces ee ecaeees ace ceaese 124
Or ATV UU aes Soca sate ae eres ek he Se oes Peceeea cc see Ses seeecpebee ee, Set cer vues acersancetabccsvaeeicuceiceetseeseee 126
TDG ee CC 0p a OP re eee See 132
(Ca aU RSTO CTS eee ec cee Re ar en ees Oe 35
INTRODUCTION

Few groups of Pleistocene vertebrates have given oceasion for such
large difference of opinion regarding the status and relation of forms
as have the bison. The extremes of views held in regard to the speci-
ation of bison have been held by Brandt' and Lilljeborg? on one hand,
who regarded all the bison, both living and extinct, as representing
a single species, and Lucas* on the other, the latter recognizing no
less than seven species from North America alone. Hay* has recently

1 Brandt, J. F., Zoogeog. und Palaeont. Beitrige, pp. 101-152 (Verhandl.
mineral. Gesells. St. Petersburg, vol. 2, 1865).

2 Lilljeborg, 1874.
3 Lucas, F. A., Proce. U. S. Nat. Mus., vol. 21, pp. 755-771, pls. 65-82, 1899.
4 Hay, O. P., Proce. U. S. Nat. Mus., vol. 46, pp. 161-200, pls. 8-19, 1913.

122 University of California Publications in Geology [ VoL. 9

added a species to those described by Lucas, though apparently not
recognizing some of the described species.

This wide difference of opinion may be attributed largely to the
diverse beliefs regarding the extent of individual variation and of
sexual dimorphism in the various members of the groups, this in turn
being due to the incompleteness and more or less fragmentary nature
of the material which could be referred with certainty to any particular
extinet species.

In the collections of the Department of Palaeontology of the Uni-
versity of California there is a comparatively large series of skulls of
Bison antiquus from a number of localities in the Pacifie Coast region
of North America, all, so far as known, of Pleistocene age, and repre-
senting, without any reasonable doubt, a single, well-defined form. It
is hoped that descriptions and comparative measurements of some of
these specimens will throw light on the problem of relationships of
the species.

INDIVIDUAL AND SEXUAL VARIATION IN EXISTING SPECIES

Due to the dissociation of parts, and the fragmentary nature of
most of the specimens which have hitherto been found the classifica-
tion of extinet bison has been based largely on the skull and horn-
cores, which afford very good comparative characters, but to what
extent they represent individual, sexual, or specifie distinctions, has
been disputed.

Before advancing evidence furnished by the fossil specimens, it
seems advantageous to summarize our knowledge of the variation in

existing species.

BISON BISON (Linnaeus)

As shown by Dr. J. A. Allen® in his memoir on the American bison,
the range of individual variation in the skull of B. bison is considerable,
much greater than that usually found within a single species, such
variation affecting the amount of convexity of the skull, shape of horn-
cores, size, relative measurements, ete.

The size in adult male specimens, according to measurements given
by J. A. Allen, has a variation of about 20 per cent, the relative
measurements being subject to a less degree of variation. The range

5 Allen, J. A.. Mem. Harv. Mus. Comp. Zool., vol. 4, no. 10, 1876, pp. 1-246,
12 pls., 1 map.

1916] Chandler: Skull and Dentition of Bison antiquus 123

of variation in length of horn-cores, considering only those specimens
which are estimated to be ten years of age or older, numbering twelve,
is about the same as that of the skull, 20 per cent. The basal cireum-
ference of the horn cores is from 10 per cent to 45 per cent greater
than the length along the upper curvature. The size of horn-cores
seems to vary much more in young animals, sometimes attaining the
full growth at an age of four to six years, at other times being far
below average size at this age. The variation in amount of curvature
of the horns is unexpectedly great, but the general direction of curva-
ture is remarkably constant.

Looking now at the sexual variation displayed by B. bison, and
referring again to the excellent table of measurements given by Dr.
Allen,® we find that the variations within the female sex are very
similar to those of the male, but that the average for all measurements
is considerably less, and that in some measurements the range of varia-
tion in male and female does not overlap. It should be borne in mind,
however, that the difference between the sexes is emphasized by the
fact that all of Allen’s female specimens were under ten years of age.
Comparing the average of the measurements of all the males with the
average of all the females, we find the latter differing from the former
as follows: size of skull, 22 per cent less, with no overlap of measure-
ments; length of horn cores, 23 per cent less; basal circumference of
horn cores, 40 per cent less, with no overlap; circumference of horn
cores relative to their length along upper curvature, 110 to 145 per cent
in males, 81 to 105 per cent in females. No difference can be found
between the sexes in the direction of curvature of the horns, the range
of variation being about the same in both.

From this it is evident that in B. bison the female differs from
the male in having a skull about 20 per cent smaller, and in possessing
more slender horn-cores. This statement is corroborated by the obser-
vation of Rhoads’ on the herd of bison belonging to the Philadelphia
Zoological Society, containing six females and fourteen males. He
points out that the chief sexual difference is in the smaller basal caliber
of the horns of the females, the variation in curvature and angle of
growth not being greater than that found within a single sex, while
their length, due to the relatively longer sheaths, is greater with respect
to the size of the body in the females, the cores, however, averaging
shorter, and being more distinctly cylindrical throughout.

6 Op. cit.
7 Rhoads, 8S. N., Proc. Acad. Nat. Sei. Phila., vol. 49, pp. 488-501, pl. 12, 1897.

124 University of California Publications in Geology [ Vou. 9

BISON BONASUS

Somparing B. bison with the European B. bonasus, we are struck
by the fact that while the two are in many respects very different from
each other, and clearly constitute distinct species, the differences in the
skull and horn-cores are unexpectedly shg¢ht, and while the average
B. bonasus has a more massive skull with longer horn-cores than B.
bison, extremes of the two species overlap each other in all respects.
So far as can be ascertained from measurements given by Allen® and
Meyer,’ B. bonasus is subject to approximately the same amount of
sexual and individual variation as is B. bison.

GENERAL ACCOUNT OF BISON ANTIQUUS
HISTORICAL

Bison antiquus was first described by Leidy’® from a fragment of
a horn-core found at Big Bone Lick, Kentucky.

J. A. Allen, in his monograph on American bison,'? included with
it a number of specimens which have since been referred to other
species. In 1897 Rhoads’? described B. californicus from a cranium
which had previously been referred to B. antiquus and which was put
back in that species by Lucas!* in 1899. Lueas also describes an im-
perfect lower jaw from Alameda County, California, and Hay** in
1912 deseribed a fairly well preserved cranium which is in Earlham
College, Indiana. So far as I am aware these are the only specimens
which have been so far described as belonging to this species.

DESCRIPTION OF NEW MATERIAL

As intimated above, there has hitherto been no adequate basis for
determination of the amount of individual and sexual variation, not
only in this species, but in any extinct American species of bison. The
abundant material, chiefly from the asphalt beds of Rancho La Brea,
which is in the collection of the University of California, affords

8 Op. cit.

9 Meyer, H. von, ther fossile Reste von Ochsen, Nova. Acta. Phys. Med.
Acad. Leop. Carol. Nat. Cur., vol. 13, pp. 101-169, pls. 8-12, 1835.

10 Leidy, Proce. Acad. Nat. Sci. Phila., 1852, p. 117.

11 Op. cit.

12 Op. cit.

13 Op. cit.

14 Hay, O. P. Geol. Surv. Indiana, vol. 35, p. 650, 1912.

1916] Chandler: Skull and Dentition of Bison antiquus 125

an excellent opportunity for such a determination in Bison antiquus,
at least. There are thirteen more or less complete crania of various
ages, four of which have the horn-cores practically perfect, four have
the entire skull perfect or almost so, and five have the dentition almost
complete. In addition to this there are numerous fragments, and a
very large series of rami, in fact parts of sixteen different animals.

Following is a general description of the specimens at hand, by
numbers :

19478. The forehead, with complete horn-cores, of an old male individual.
Pleistocene of the John Day region, Oregon, Figs. la and 1b.

21154. A complete cranium of an adult male, with one horn-core. Rancho
La Brea. Figs. 3a and 3b.

21153. A complete cranium of a young adult male with both horn-cores.
Rancho La Brea. Figs. 4a and 4b.

21152. A skull of a young adult, complete with the exception of the outer
part of both horn-cores. Inner pillar of M1 connected, those of
M2 and M? unworn. Rancho La Brea. Figs. 7 and 9.

21151. A complete eranium of an adult, with both horn-cores. Rancho La
Brea. Figs. 2a and 2b.

21184. A complete skull of an adult, on mounted specimen in University of
California. Rancho La Brea.

21182. An imperfect cranium of a young adult, with both horn-cores broken.
Rancho La Brea.

21188. A complete skull with the exception of a few teeth, of middle-aged
animal. Inner pillars of M! and M2 connected, that of M® only
slightly worn. Rancho La Brea.

21186. An incomplete cranium of a young adult, with one horn-core missing.
Rancho La Brea.

21187. Portion of skull, with one horn-core, and a few teeth. Rancho La
Brea.

21188. Nearly complete skull of a calf, but both horn-cores broken. Milk
molars present, permanent M1! just coming in. Rancho La Brea.

21185. Skull of old animal, complete with exception of one horn-core. Inner
pillars of all molars well worn. Rancho La Brea.

21190. Incomplete cranium of young adult, with both horn-cores broken.
Rancho La Brea.

21443. Left half of upper jaw, with four teeth. Old, inner pillars of all
molars well worn. Rancho La Brea. Fig. 10.

21444, Premaxilla and front part of maxilla of rather young animal. Inner
pillar of M1 slightly worn. Rancho La Brea.

21433. Imperfect ramus, old. Only molars present. Rancho La Brea.

21432. Imperfect ramus, old. All teeth present. Rancho La Brea. ,

21432. Imperfect ramus, old. All teeth present. Rancho La Brea.

21434. Ramus, old, complete except for M® and P+. Rancho La Brea.

21442, Complete ramus, middle-aged. Rancho La Brea.

21445. Incomplete ramus, middle-aged. Only molars present. Rancho La Brea.

21184, Restored ramus, middle-aged, all teeth present. Rancho La Brea,

21189. Complete lower jaw, with both rami, only P2 absent. Middle-aged.
Rancho La Brea. Fig. 11.

126 University of California Publications in Geology _ |Vou.9

21440, Complete ramus, all teeth present. Middle-aged. Rancho La Brea.

21181. Complete ramus, young adult. Rancho La Brea.

21441. Complete ramus, Dm? and Dm still in, but nearly pushed out. Rancho
La Brea. Figs. 12a and 12b.

21488. Incomplete ramus, P2? and P3 unworn. Rancho La Brea.

21439. Incomplete ramus. Dm? still in place. Rancho La Brea.

21485. Incomplete ramus, M2 unworn, M3 not yet appeared. Rancho La Brea.

21180. Complete ramus. Milk dentition complete. Rancho La Brea.

21437. Front part of ramus. Milk dentition complete, only M1 in place.
Rancho La Brea.

21436. Complete ramus, Dm’ unworn. Rancho La Brea.

CRANIUM

An examination of the measurements of all the specimens of B.
antiquus considered in Table I, execept 21183 and 21188, which are
excluded on account of their youth, shows that in none of the meas-
urements of the cranium is there more than 20 per cent variation,
and in some of the measurements considerably less than that. It is
strange that the measurements of the facial region are throughout far
more constant than those of the cranial region. For instance, in the
basinasal length there is a variation of over 16 per cent, and in the dis-
tance from the foramen magnum to the rear of the hard palate, about
20 per cent, while in none of the facial measurements does the variation
exceed 10 per cent. The same tendency for greater variation in the
cranial portion of the skull is shown by the table of measurements
given by Allen for B. bison, but is not as marked.

An examination of the measurements shows at once that the speci-
mens fall into two natural groups, one with small, slender, horn-cores,
the other with large, robust horn-cores. By analogy with the existing
species, we may safely assume that the former are females, and the
latter males. While there may be slightly smaller average measure-
ments of the skull proper in the females than in the males, the differ-
ence is inappreciable. In the horn-cores, however, the difference is
striking. From tip to tip of the horn-cores there is a variation of
about 10 per cent in the males, and 12 per cent in the females, but there
is a difference of over 20 per cent in the average measurements of the
two sexes, with no overlap. Looking now at the measurements of single
horn-cores along the upper curvature, we find a still greater difference,
in fact, over 25 per cent, since the difference in extent of horns is due
entirely to the length of the horn-cores, the width of the forehead being
fairly similar in both sexes. In circumference at the base of the horn-

Lower border o
rear of nasa

Occipital crest
along mediar
Rear of condyle
Line joining 1
premaxillae .

Lower border <
rear of hard

Rear of hard
maxillae .......

Width of forel
horn-cores ...

Width at nar
horn-cores a!

Width betweei
base of crov

Width betwee
ners of P? ..

Antero-posteri
Length of nas:

Width of nas
Wimles 2.s...2.2...4

Same as last me:

Tip to tip of h
Length of hi

curvature ....
Circumference
Circumference

Diameter of h
Dorso-ven

Antero-po!
* Appro

TABLE I

MEASUREMENTS OF SKULL

Me An auetasernin OS

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en magnum to
Cor Bader St “(basinal eacthe 270 mm. 270 ...... eee ene -.. 255 285 290 276 270 285 260 257 263 260 220 PET) PY. ce iis 292 ees

Occipital erest to fronto-nasal suture

iFig median Line 240 245 214 210 265 208 265 272 276 240 252 268 242 220 244 245 210
alont

Rear of condyles to tip of premaxillae cee seceee seemee sees seen secs seeeeeneceee sees 610 ...... 682) ...... Gib pea ee.
Line joining rear of orbits to aD Os: We ot ee IS nc eee UL ees COA on SCL I ce 4402) 8. a eee
premaxillae “Fe
of f en magnum to
Toret tre of foram emmerine Sit ees eee Me tae Pas, SETI scx DAT! 2: 200% cane eee 156 BILE 202 cnn ee
d palate to tip of pre-
ES uns B Ee ee cro cum mm Sin op cm 3386... ARH CBD pe et en ena! SEB coms CEYE a. aus
Width of forehead between bases of % x P
born-cores ... seme CPN 330 255 214 270 205 347 417 397 406 3820 340 ...... 305 275 195 290 297
Width at magne point ReGwaa
horn-cores and eye-sockets ... 2 270 240 210 267 206 303 309 292 304 270 290 253 265 ...... a 187 256 271 ...... B86 rsasy ke

Width between outer sides of we FG

3G OL COE cartoons, WEN eee) om seers ate. eo, tee WGI) eae GRY serve
Width between anterior inner cor- 482
ners of P* .. oS se oo ce ce PR) ee LOST eo.
Aulirggesterior diameter of arial 70 CA) ates oes 77 70" 70" (85) 69701) 73)
Length of nasal boneS ...........cscecesseee sees 2905: A. eS San ine Sache een) Meee 20S ees 222 ......
Width of nasal inane) in straight
1B seeaeeenene E WN) ee eee aS ee S10 2ieeeses
Sameaslast meamnrement with curvature : 180 Mey eee ek ce 120
413x2
Tip to tip of horn-cores . 640) 515 468 560 395 975* =826 817 ...... Yl) (6) ees
Length of horn-cores along upper
curvature ... PAN) se WAG TGP) ee Sere 844 275 (275)... Ppl Dey ee 180 190* 228 ...... 2350... v 285 290...
Gieanference of horn-cores at base. 230 270* 200 163 200 178 342 310 300 306 219 224 206 198 9205 220 140 212 220... GD saree 364
ireumference of neck of horn-eores.. 220 250 315 295 288 295 228 235 223 208 220 240 188 = 240 nn cece cece vee ee
Diameter of horn-cores—
Dorso-ventral 1 G5 ae cere 102 102 100 65 70 61 63 65 70 42 68 GPR aente 115? 1037 102*
Antero-posterior (Ol Sige gene ee eee 105 104 92 96 68 65 65 60 64 68 43 67 «= 71_—..... 110% 909 122*

* Approximate,

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, a
{ ay oy oo ee Se ee Rein ngs
2 — ‘
+4 ore Pape. ¢> r
= & ~ = > oli wei

on

1916] Chandler: Skull and Dentition of Bison antiquus 127

cores there is a 33 per cent difference between the two sexes, resulting,
of course, in the females having considerably more slender horns. The
measurements also show that the neck of the horn-cores, 7.¢., the por-

Figs. la and 1b. Bison antiquus Leidy, g. Cranium and horn-eores. No.
19478, X ¥%, John Day region, Oregon. Fig. la, dorsal view, perpendicular to
forehead; fig. 1b posterior view, at right angles to dorsal view.

Figs. 2a and 2b. Bison antiquus, Leidy, 9. Cranium and horn-cores. No.
21151, X \%&, Rancho La Brea beds. Fig. 2a, dorsal view; fig. 2b, posterior view.

tion between the forehead and the rugose horn-covered portion, is of
smaller caliber than the base of the horn-core itself in the males, but
is greater in females.

128 University of California Publications in Geology [ Vou. 9

Reference to figures la, 2a, 2b, 3a, 3b, 4a, and 4b make it evident
that the variation in the horn-cores of B. antiquus as regards their
curvature, general form, and relations to the skull are very slight.
Comparison of figures of the old male from the John Day region (figs.

Figs. 3a and 3b. Bison antiquus Leidy, g. Cranium and left horn-core.
No. 21154, X %, Rancho La Brea beds. Fig. 3a, dorsal view; fig. 3b, posterior
view.

Figs. 4a and 4b. Bison antiquus Leidy, g. Cranium and horn-cores. No.

21153, X %&, Rancho La Brea beds. Fig. 4a, dorsal view; fig. 4b, posterior view.

1916] Chandler: Skull and Dentition of Bison antiquus 129

Figs. 5a and 5b. Bison bison (Linnaeus), ¢. Cranium and horn-cores. U. C.
M. V. Z. No. 5597, X %, Great Plains region. Fig. 5a, dorsal view; fig. 5b,
posterior view.

Fig. 6. Bison bison (Linnaeus). Nasal bones. U. C. M. V. Z. No. 5596,
x \, Great Plains region.

ig. 7. Bison antiquus Leidy. Nasal bones. No. 21152, Rancho La Brea

Fig B tig Leidy. Nasal } No. 21152, Rancho La B

beds.

130 University of California Publications in Geology [ Vou. 9

la and 1b) shows that the horn-cores are almost identical with those of
two large males from Rancho la Brea, shown in figures 3a and 3b, and
4a and 4b, and also with those of the male from the Pilarcitos Valley,

Jalifornia (figured by Rhoads, pl. 12, fig. 2), and the male in Earlham
College (figured by Hay, figs. 2 and 3). Viewing figures 2a and 2b,
representing a female from Rancho la Brea, it is evident that aside
from the smaller size and relatively somewhat more slender form, there
is no appreciable difference in the form of the horn-cores. One of
the most characteristic and most readily recognizable characters of the
species, as has previously been pointed out by Lucas and Hay, is the
angle which the basal portion of the horn-cores makes with the longi-
tudinal axis of the skull. In Bison bison, and in all other American
species so far described, the horn-cores make a more or less obtuse angle
with the median line of the facial portion of the skull (see fig 5a), while
in B. antiquus they are inserted almost at right angles (figs. la, 2a,
3a, and 4a). In B. bison the angle bounded on one side by a line
from a point at about one-half the distance from base to tip of a horn
core along the middle line of the core to the median line of the skull,
and on the other side by the longitudinal axis of the skull, varies from
110° to 125°, usually being approximately 120°. In B. antiquus, on
the other hand, the angle never exceeds 100°, and is frequently an
almost perfect right angle. The widest angle made with the skull in
any specimen of B. antiquus so far described is that of a very young
animal, little over half grown, from Rancho la Brea, (21188). In
this specimen the angle is about 100.°

Considerable variation exists in the amount of convexity of the
forehead, as can be seen by reference to figures 1b, 2b and 4b. This
convexity seems to increase somewhat with age, though there is a great
deal of variation which is purely of an individual nature.

The amount of variation in the size of the lower jaw is remarkably
slight, there being only about 5 per cent difference in length from tip
to angle in the extremes of five adult specimens, as shown by Table
III. The measurements vary to such an extent with age that it is
impossible to distinguish males from females, although, judging by
analogy with the modern species, there is probably a slight sexual
difference in size.

Comparison of the measurements of the skull and horn-cores shows
that B. antiquus differs from both the existing species in the relative
breadth of the skull. The length, as shown by several different
measurements, is approximately the same for all three species, while

1916] Chandler: Skull and Dentition of Bison antiquus 131

the breadth in B. antiqwus in both sexes is one and a third times that
in the corresponding sex of the modern species. There is no notice-
able difference in size of the orbits. The nasal bones of B. antiquus
differ from those of B. bison in being relatively shorter and broader,
and less arched, tapering more gradually to the tip; so that the notch
near the distal end is not so conspicuous. These differences are well
brought out by a comparison of figures 6 and 7, and of the measure-
ments in Table I.

The horn-cores are longer and relatively more slender in B. antiquwus
than in B. bison, the length of the horn-cores in the females of the
former about equalling that of the males of the latter, the basal eir-
cumference, however, being much greater in the males of B. bison
than in the females of B. antiquus, but not as great as in the males
of the latter. As previously stated, the angle of growth of the horn-
cores is considerably different in B. antiquus from that in other Ameri-
can species, or in B. bonasus, but the curvature is much the same, there
being a sagging below the level of the forehead, then an even upward
curvature, and a more or less pronounced reflexion of the tips. (Com-
pare figs. 5a and 5b, with figs. 1-4.) In B. bonasus the horn-cores seem
to be relatively even smaller than in B. bison, but the difference in
skull and horn-cores between B. antiquus and either of the modern
species is greater in every respect than that between the two existing
species.

DENTITION

The dentition is known by teeth in many stages of wear, that of
the lower jaw being especially well represented. The teeth of bison
are of little value from a systematic point of view, the individual
variation within a species so far overbalancing any average specific
difference that may exist that it is difficult to find any constant, reliable
specific difference except in size. Hay’ has shown that the amount
of complication of the enamel walls of the lakes of the molars shows a
tendency to vary specifically, B. latifrons having a very simple pattern,
and B. regius relatively a very complicated one. Hay states that in
several Recent specimens of B. bison he finds no inflexion of the enamel
on the sides of the lakes of the upper molars, and this statement is
borne out by my own observations. Allen'® figures a specimen of B.

15 Op. cit.
16 Op. cit.

ile University of California Publications in Geology [ Vou. 9

bison from Big Bone Lick in which the pattern is complicated as in
Hay’s figure of B. regius. It seems possible that Allen’s specimen
was in reality B. antiquus, since the latter has been found in the same
locality, and, as will presently be shown, has more complications of
the enamel than have Recent specimens of B. bison.

TABLE II
MEASUREMENTS OF TEETH OF UPPER JAW
DN
ge
Ye) on on xt xt LS a oO 25
(os) a fo a) (oo) bi) ios) Ye) o sec
ml ~t ian] ial xt ian ian ial : o>
n n n n n n Qn a A068
Length of upper series Milk
of cheek-teeth _........ 1G Sima Ne SS lie ee cou econ 161 series 144
Length of premolar
S@VLCS' fe seteee vesesee eters 65 68 60 67 OR Means 66 0 58
Milk
Length of molar series 100 UO} SUA ee ee 104 78 ~=89
Tee NUewaven el ee ee ene 2 eee 21 20 Db) ieee 22 ee ee
JEP Nita ol pee ee eer G6 ee 15 2 M7 De eee iy ees
8 Wh ern oyaereeececeeeceee es 205 2ee 19* 22 25 22 2a eee
Ps Width 23 17 2 21 22 PAY Meee bepet:
P4 Length ... 19 21 119) 21 23 20 24. ae: 19
P+ Width 26 28 25 2 25 26 2 Peace 21
Milk
IMLS Wyesayen niet oe teresa 30 29 2 26 32 27 333) 26 86.26
UME AVANCE ere eee 31 30 28 2 25 2 27 19 924
Milk
M2 Length ..............--.-- 34.5 37 34 BS esr eee 36 30 32
WA NW Valle) at) enero ree 33.5 31 30 © 2 ee 26 20 23
Milk
M3 Length ..... eee 36 39 36 SiG} eee Serer 34 oo 30
WISE Whaley ee 32 29 33 Gee see 26 21 22

* Approximate.

Measurements of upper teeth of several specimens are given in
Table II, the leneth being measured on the grinding surface, the
width at the base of the exposed portion of the crown. The length
and width of the individual teeth, as well as the length of the tooth
series as a whole, varies considerably with wear. The length of the
tooth decreases very considerably, while the width remains more nearly
the same, increasing shghtly for a while, then decreasing toward the
roots. Comparison with measurements of the teeth of B. bison (U. C.
M. V. Z. 5597) which exhibit approximately the same degree of wear
as 21185, shows that the upper teeth of B. antiquus are considerably
larger. The structure of the upper premolars does not differ in any

1916] Chandler: Skull and Dentition of Bison antiquus 133

Figs. 8-12. Bison antiquus Leidy. Fig. 8, teeth of right upper jaw, P2 to M1
inclusive. No. 21444, x 1%, Rancho La Brea. Fig. 9, teeth of right upper
jaw, P* to M* inelusive. No. 21152, XK 14%, Rancho La Brea beds. Fig. 10.
Teeth of right upper jaw, P+ to M2 inclusive. No, 21443, & ™%, Rancho La Brea
beds. Fig. 11. Teeth of left lower jaw. No. 21189 & 4%, Rancho La Brea
beds. Fig. 12a, teeth of right lower jaw. No. 21441, & %4, Rancho La Brea
beds. Fig. 12b. Inner view of right lower jaw. No. 21441, X 14, Rancho
La Brea beds.

134 University of California Publications in Geology [ Vou. 9

important details from that of B. bison, except that the posterior inner
tubercules of all of them are better developed, in slightly worn teeth,
(e.g., 21152) forming a minute lake posterior to the main one. See
figs. 8, 9 and 10.

M* when once worn flat is almost square with the lakes very
narrow and V-shaped, in well-worn teeth the anterior horn of the
posterior lake and the posterior horn of the anterior lake reaching
relatively far toward the outside (fig. 10).

The sides of the lakes are very slightly indented on 21152 and
21444 (see figs. 8 and 9), while in 21183 there is an invaginating lobe
on the anterior side of the posterior lake as in Allen’s pl. 10, fig. 7,
ascribed to a fossil B. bison. M?* has wider lakes than M*, with a more
or less well developed invagination of the enamel on the posterior side
of the posterior lake compare 21152 (fig. 9) and 21448 (fig. 10), the
latter also having an invagination on the anterior side of the anterior
lake while on more worn teeth (21183 and 21185) there is no such
invagination to be seen. Upper milk molars 2 and 3 are present in
21188, and but slightly worn. They resemble permanent molars, ex-
cept for their smaller size, and the relatively greater size and different
form of the small inner lobe between the protocone and hypocone. In
Dm* of 21188 this lobe is long and tongue-lke, about 8 mm. long, with
its widest anteroposterior diameter only about 2.5mm. It is less con-
spicuous in Dm?.

The teeth of the lower jaw vary in much the same way as those of
the upper, and show the same differences relative to B. bison. There
are specimens showing teeth in all stages of wear, from unworn milk
molars to permanent molars which have been worn below the level of
the lakes. Figure 11 shows the lower teeth of 21189, of moderate age.
P, is a very simple tooth with an inner and outer furrow, slightly
nearer the posterior end of the tooth. P, has two open interior valleys
and a slight posterior outer furrow, the anterior inner furrow being
more or less bilobed in some specimens, especially in 21181. In P,
there are large open anterior and posterior valleys on the inner side
and a smaller one on the anterior inside corner. There is also an outer
furrow, situated rather posteriorly. M, and M, have very narrow
erescentic lakes, the outer side of the crescent being shghtly pushed in.
The outer pillar, when moderately worn, becomes connected with both
the protoconid and hypoconid. It is not as large as the inner pillars of
the upper molars. In M, the pushing in on the base of the crescents
is still more prominent. In this tooth there is a slight outer lobe be-

Anterior end

Greatest heig
measuring °

Posterior en

back of an
Front of toot
Length of low
Length of pr
Length of mi

P, Length ..
P, Width ....

P, Length ..
P, Width ....

P, Length ..
P, Width ....

M, Length ..
M, Width ..

M, Length ..
M, Width ..
M, Length ..
M,; Width
Length of m
Dm, Length
Dm, Width
Dm, Length
Dm, Width
Dm, Length
Dm, Width

TABLE I11
MEASUREMENTS OF LOWER JAW AND DENTITION

§ Ng N< Na
Boe Gg os 8
Pelverp eee ek
‘'S & | = e
Al eckh Geel GER Go oS Go 8 & © 8 8 g@ 8s FF SS & Ss Oe
Anjerior end to angle of lower jaw -..... 406mm. 397 BER) eres comp 454 430)... 430 487 440 2 oe 415 400s 1 ee ee
el ue
test height of yertical ramus
man@nDemeeae en eos _. 158 140
4 ies to
Posterior end of tooth series
atk of ANIC aanwerevereeneeeeerneee neneee seeens enern 142 149
Froat of tooth series to tip of jaw -..-- - ann 150 137
[argh of lover series of cheek eeth 152 165 153 175 149
Legth of premolar series ees ce 60 54
Lagth of molar series .. 97 116 95
13 12

P, Length

1 ee E
B, Length

B, Width 13
P, Length 21
ivi peeing Se 14
V, Length 29) 25
V, Width mks] 17
V, Langth .. 32 4 29
VY, Width 19 (3 20
V, Length _ 42/3 43
¥, Width Wa 18

Lagth of milk molar series
Dz, Lengt
Dm, Width
Du, Length
Do, Width _.
Do, Length ..
De, Width .
* Approximate.

=~
P P “14
it :
rs ri Vey styl ree oa ty '
ee y
ed =)
4 wh

*, « - i “5 a
‘ hi Ae ATES eee
i : Saas
* i rane - whee
: ete t f

- Ot
7 a Lt
; asa oy
i &
: ( Vite oy fai A be
cht a ¥ i 1 Re it
- s) : : awison Rubee
; ee ee eee ae a
ri 7 Belt) ef Ws
( Be : | S# costal Medi
: % 15
| bo) aay ow WAVL iaawme OE
:
;
: a eatin dees
- 7 ews how eoreee
:
3 is aaeet, waeeee
‘4

1916] Chandler: Skull and Dentition of Bison antiquus 135

tween the second and third lobes, but not as well developed as that
between the first and second lobes. The third lobe is very simple.

Milk teeth are present in a number of jaws. Dm, somewhat re-
sembles permanent P,, having two open interior valleys and a single
outer one; it is considerably smaller, however. Dm, resembles perma-
nent P, in size, but differs from it in having the posterior inner valley
closed, forming a lake (fig. 12a). Dm, is trilobed, having large tri-
angular outer lobes between the first and second and between the
second and third main lobes, as well shown in fig. 12a, representing
a Dm, about to be shed, as can be seen from fig. 12b. When unworn
Dm, is almost as large as permanent M*.

The sequence with which the permanent teeth come into function
is as follows: M', M?, P?, then almost simultaneously P* and M®, and
finally P*.

CONCLUSIONS

Bison antiquus, as represented by an excellent series from Rancho
La Brea, and by other specimens, is subject to approximately the same
sort of individual and sexual variation as is found in the modern
species. Individual variation occurs in size and relative measurements
of the skull to the extent of about 20 per cent or less, while the sexual
difference in these respects is small, apparently less in B. antiquus
than in B. bison or B. bonasus. The horn-cores show approximately
similar individual variation within a sex, but the average length in
females is about 25 per cent less, while the basal circumference is about
33 per cent less, with no individual overlap in either case. From
this it is evident that the females have not only smaller, but more
slender horns. This corresponds to the condition in the existing species.
The variation in general form, curvature, and angle of insertion of
the horn-cores is very slight, and these make reliable specific characters.

The dentition varies so little in different species, that specific
identification by means of the teeth is almost impossible. The size of
the teeth, and the amount of indenting or folding of the enamel walls
of the lakes varies to some extent in different species, but it is ap-
parently so variable within a species as to be of very little taxonomic
value. In general the teeth of B. antiquus have the enamel walls of
the lakes more compheated than have modern specimens of B. bison.

Transmitted June 21, 1916.

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2, pp. 137-159, 1 map rf Issued February 8, 1916

NAL STUDIES IN THE CRETACEOUS

‘THE SANTA ANA MOUNTAINS OF

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3. The Geology of the Sargent Oil Field, by William PF. Jomes ........2...:c.ctsccesscseescoreeenee
4, Additions to the Avifauna of thie Pleistocene Deposits at Fossil Lake, Oregon, | by

Loye Holmes Miller ...n.c202---|ses--veccncarenceseecsssonnenisy-nannene eas-saadeasutlesds mean cee anes ae ee :.
5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by Joby A, Reid
6. Note on a Gigantic Bear from the Pleistocene of Rancho La Brea, by John C.
Merriam.
7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Thaseel) P
by John C. Merriam. Ry:
Nos. 6 and 7 fi O16 COVER 25-2. .1a.0cea:sceconetpceoctacpasecel|swatinepanaesonenchsutaes anneal 10
8. The Stratigraphic and faunal Relations of the Martinez Formation to the Chieo
and Tejon North of Mount Diablo, by Roy HE. Dickerson .............-.scescssnessesneres suf
9. Neocolemanite, a Variety of Colemanite, and Howlite from Lang, Los Angeles
County, California, by Arthur S. Halle oon... coiogpeecccreenenere-ustesansos eae nee costs
10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor...
11. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern ~
Nevada, by John C. Merriam. Part IJ.—Vertebrate Faunas .........-.-.seccm ‘
12, A Series of Eagle Tarsi. from the Pleistocene of Rancho La Brea, “by Loye Tine
MMe ono. cih chet se ncnctsedboorcceipanieda suey cteapusaensgeciece sosedtecgetvaeas deptaneaeetns ae Uae tee
13. Notes on the Relationships of the Marine Saurian Fauna Described from the Triassic
of Spitzbergen by Wiman, by John C. Merriam.
14, Notes on the Dentition of Omphalosaurus, by John C. Merriam and Harold C. Bryant. —

Nos, 13 and 14 in ome cover 2200.12.) spl ee et eee ee
15. Notes on the Later Cenozcie History of the Mohave Desert Region in Southeastera 4
California, by Charles Laurence Bakker ..25:--c-dcs1scesvasestasone encdomexsarene none ee

16. Avifauna of the Pleistocene Cave Deposits of California, by Loye Holmes Miller
17. A Fossil Beaver from the Kettleman Hills, Califopnia, by Louise Kellogg -.cscsoccsccee
18. Notes on the Genus Desmostylus of Marsh, by Johh 0. Merriam .........--..ec..-e DS ;
19. The Elastice-Rebound Theory of Earthquakes, by Harry Fielding Reid ............ ee"

VOLUME 7.
1. The Minerals of Tonopah, Nevada,.by Arthur 8. Eakle . E e
2. Pseudostratification in Santa Barbara County, California, ‘by ‘George ‘Davis L
WAG He 5... e-nicnnpe Seve guosecietesennde tea dees Se Resa to acca Dn ce em pat! J.
3. Recent Discoveries. of Carnivora in the Pleistocene of Rancho La Brea, by y Joan
Merriand ...2..) 20-bit ceaaerenc siete dhe ese g seh he hea Sees eee) Hy
4. The Neocene Section at Kirker Pass on the North Side of Mount Diablo,
1 OM C1: 5) aan es te ME Smee ee moe My ER Oy ea Be |
5. Contributions to Avian Palaeontology from the Pacific Coast of North
Loye Holmes Maller :...i-2hoctste: ot ou tai. aaa ee ate eee ae

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 12, pp. 137-159, 1 map Issued February 8, 1916

FAUNAL STUDIES IN THE CRETACEOUS
OF THE SANTA ANA MOUNTAINS OF
SOUTHERN CALIFORNIA ates

\ysOMian geste
ns : ISP.

BY
EARL LEROY PACKARD * APR 24 19]

igen RTCA te
CONTENTS a
Marnie O GNU Gb OMe veces seco actrees eee ee Pe ee us eek eee Bee od. 7.2: ee -
VEER aie OE Te UNCSY a Dia teceh eke ey aks) eee ee SEE
Geolopiymotatine ENC C1 OD cere. c= oases es sean sase net nag oe pe cede spa senoeh eee ceca scnseus ecu getevecetscstsies
General Geologic Relations -........2...22.-..2::22:se10eeeeeee eee Paes sd cceenoeete seen tcaceie ee 139
PDR A UU COMMOMIN ATOM! fessceeeetuscceenscoseete. seeea se. feces see en esse cesauseeeaccecesss se eaees ret eee 140
ASV) CON auWoXayi (CeCe 0 eee oe ae ee an ae ee ee oe een eee Pe 141
TENURE 142
Generali @ nara er. ee 2. ete seers Nees ee es pe ee ead 8 eau te eee 142
BB) Ean cll eZ OT Cs era a em esc ea eet UN eee ee ad teat Secon se ee 143,
Relation to other Cretaceous Faunas of California .....020..0220-..0e eee 150
Relation to Foreign Cretaceous Faunas -....22..2...2..2...:cc--ccecceeceesececeeeceeeeeeeeeeeeees 156
ENERGY Aaa PE OT a = ee ee eee 157
BS ULTAD TIN UTA ae eee rane are ee TE We 8, Pepa veer toh per ete ere 158
INTRODUCTION

The large number of fossiliferous localities oeeurine within the
Cretaceous beds flanking the western slope of the Santa Ana Mountains
afford an unusual opportunity for faunal studies in the Upper Cretace-
ous of the Pacific Coast. Detailed studies of the faunal successions in
this region were carried on by the writer in connection with the work
of the University of California Summer Session class in Palaeontology
in 1913. Collections in the Cretaceous were made at seventy-two
localities, for nearly all of which the stratigraphic position is definitely
known. These stations are well distributed throughout the two thou-
sand feet of strata in the section and are situated along a strip about

138 University of California Publications in Geology [ Vou. 9

thirteen miles in length. The large fauna is divisible into three zones,
each of which has been designated by the name of a characteristic
species. This section may be regarded as a type region for reference
of faunal zones of the Chico group.

The writer wishes to thank Professor John C. Merriam for his
interest in, and general supervision of, this study, and to acknowledge
the assistance given him in the field by Dr. Roy E. Dickerson and the
other members of the field party.

REVIEW OF THE LITERATURE

The first recognition of faunal differences in the Cretaceous of
California should be credited to W. M. Gabb,? who divided the Cretace-
ous into the Shasta and Chico groups on the basis of faunal differ-
ences. C. A. White? in 1885 divided the Shasta group of Gabb into
the Knoxville and Horsetown beds. The fauna obtained from White’s®
Wallala group, which was then thought to be intermediate in age
between that of the Horsetown and Chico, is now considered to be but
a phase of the lower Chico.t| Dr. T. W. Stanton has studied the Cali-
fornia Cretaceous in its various aspects, and has contributed largely
to our knowledge of the different faunas.

The classification of the California Cretaceous as given by White
remained unchanged until in 1902 F. M. Anderson divided the Knox-
ville into an upper, or Paskenta horizon, and a lower, less fossiliferous
one to which he apphed the term Sub-Knoxville.®

Anderson recognized two faunal stages in the Chico, under the
names of Upper and Lower Chico. His conclusions were derived from
compiled and revised lists of species, which were, as he states, ‘‘massed
from a number of the more significant localities.’”® Regarding the
Horsetown and the Chico Anderson writes that ‘‘the transition of
faunas is more gradual than it has been in any other basin of the
Pacific border; and for that reason the faunas representative of the
1Gabb, W. M., Palaeontology of California, vol. 2, p. xiii, 1869.

2 White, C. A., On the Mesozoic and Cenozoic Palaeontology of California,
U.S. Geol. Surv. Bull. 15, p. 19, 1885.

3 White, C. A., On new Cretaceous Fossils from California, U. 8. Geol. Surv.
Bull. 22, 1885.

4 Willis, Bailey, Index to the Stratigraphy of North America, U. S. Geol.
Surv. Professional Paper 71, p. 647, 1912.

5 Anderson, F. M., Cretaceous Deposits of the Pacific Coast, Proc. Calif.
Acad. Sci., Third Series, Geol. vol. 2, p. 47, 1902.

8 Op. cit., p. 25.

1916] Packard: Cretaceous of Santa Ana Mountains 139

different horizons are not so easily distinguished.’’* Anderson chose
therefore the following localities outside of the Great Valley as typical
of the Lower Chico:* San Diego, California, Silverado Cafion, (Santa
Ana Mountains) Henley, California, and Phoenix, Oregon. He assigned
the type Chico of Chico Creek, Pence’s Ranch, Texas Flat, and Tusean
Springs to the Upper Chico. All of these localities are in the upper
portion of the Sacramento Valley.

The Silverado Cafon fauna apparently includes only the lowermost
fauna from that region. The fauna listed from San Diego, obtained
from Point Loma and Point La Jolla, is comparable to the fauna from
the lower zone of the Santa Ana Mountains. The different faunas
which are considered as equivalent to the upper Chico include the
fauna from Chico Creek. It thus appears that Anderson recognized
that the Chico Creek fauna represented but a portion of the Upper
Cretaceous of California.

A review of the geologic literature dealing especially with the
Santa Ana region has been amply covered in a recent paper by Dr.
Roy E. Dickerson entitled ‘‘The Martinez and Tejon Eocene and
Associated Formations of the Santa Ana Mountains.’’®

GEOLOGY OF THE REGION
GENERAL GEOLOGIC RELATIONS

In the rocks of the Santa Ana Mountains the following geological
divisions are represented ; a basement complex of questionably Triassic
age ; Upper Cretaceous, Chico; Lower Eocene, Martinez; Upper Kocene,
Tejon; the lowermost Miocene, Vaqueros; and alluvium of probable
Pleistocene age. The intrusives and the metamorphosed sedimentaries
of the basement complex comprising the core of the range are un-
conformably overlain by the Cretaceous sandstones and conglomerates.
Both the Martinez and the Tejon are represented by small remnants,
which are shown by Dickerson’? to be discordant with both the under-
lying Cretaceous and the overlying Miocene. The latter strata sue-
cessively overlap the Tejon, Martinez, and Chico, and at Arroyo
Trabuco are in contact with the basement complex.

The Cretaceous occurs on both sides of the range. It outcrops on
the western flank of the mountains in a band having a maximum width
7 Op. cit. p. 25.

8 Ibid., p. 26.

9 Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, pp. 257-274a, pls. 26-28, 1914.
10 Op. cit., pp. 263-267.

140 University of California Publications in Geology [ Vou. 9

of about three and one-half miles, tapering to a point at a distance of
about thirteen miles to the southeast. On the eastern side of the range
the strip is narrower, being about a mile in width and three in length.

The structure of the Cretaceous of the Santa Ana Mountains
appears to be that of an asymmetrie anticline, the eastern limb of
which has been faulted down and partly concealed by subsequent
formations. The strata of the western limb of this fold south of Black
Star Canon have a strike of about N 45° W and a westerly dip of 25°
to 30°. On the west side of this canon the beds are gently inclined,
the dip in places not exceeding ten or fifteen degrees. Still farther
north the structure becomes complicated by gentle minor folds. North-
east of Coal Mine Hill a carbonaceous stratum marks one limb of a
small anticline. Coal Mine Canon, north of Sierra Cafion, is nearly
parallel to the axis of a pre-Tejon fold which involved the Martinez
and Chico strata.

THE TRABUCO FORMATION

The basement complex comprising the core of the Santa Ana
Mountains is unconformably overlain by a massive red conglomerate,
which is traceable as a distinct mapable unit for a distance of about
ten miles along the strike. It occurs as a narrow belt three or four
hundred feet in width, extending from North Star Canon nearly to
Trabuco Canon. The term Trabuco formation is here proposed as
a local name for these red beds so well exposed along the western
flank of the Santa Ana Mountains.

The best section of the Trabuco formation may be seen in Harding
Canon, where the beds have a dip of about 45° § and a strike of N
15° W. The metamorphosed sedimentaries of the basement complex
dip about 45° N and strike N 15° W. In places the low dip carries
the red basal conglomerates some distance up the slope of the ridges
into the area of the basement complex in such a way that small isolated
patches of the beds may be found, separated by erosion from the main
mass, or connected with it by a thin veneer of residual gravels.

The loosely cemented conglomerates of the Trabuco formation de-
velop upon weathering a rounded topography which is in marked
contrast to the abrupt cliffs formed by the gray conglomerates of the
overlying Chico. The conglomerates of the basal Chico le in apparent
conformity upon those of the Trabuco, but in most localities the change
from the red to the gray beds is very abrupt, suggesting an erosion.
interval. Direct evidence for such a structural break is lacking. That

oie a

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Sketch map of a portion of the Santa An
errace deposits; Vv, Tertiary Miocene; Tt}
retaceous Trabuco; BC, Basement Complex.

Sketeh Map of a portion
terrace deposits; Vv, Tertia:

istocene
i and Pleis
1, Alluvium
drangle. Qal,
ia, a part of the Corona Qua
ins, California,
Mountains,

of the Santa Ana
etaceons Trabuco} BC, Bas

ico; Kt,
ous Chico;
Y; ; Ke, Cretace
iary. inez Eocene;
Eocene; Tmz, Tertiary, Martin
j jocene;
i ; j, Tertiary, Tejon J
'Y Miocene; Ttj, y iss
sitet Complex. Scale, 4 inch=1 mile.

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GipWilrsizet: sat wsussort pps Fe iat 1911890)
lint Cox deat ot sla sxeiqeaoD Hestonae y

1916] Packard: Cretaceous of Santa Ana Mountains 141

the Chico conglomerates are conformable upon those of the Trabuco
appears to be indicated at one locality where a gradation from a red
to a gray conglomerate was noted.

These red Trabuco conglomerates are composed of both angular
and water-worn boulders varying in size up to those having a diameter
of three feet. The boulders represent a considerable range of rock
types, the majority of the igneous rocks being basic. In places subord-
inate bands of red sandstone occur interbedded with the conglomerates.

The peculiar color, the angular form of most of the pebbles and sand
grains, and the lack of marine fossils suggests that the Trabuco forma-
tion was deposited upon a narrow coastal plain, by torrential streams
arising in a mountainous region but a short distance to the eastward.
After about two hundred feet of this material had been laid down,
marine conglomerates of the basal Chico accumulated within the waters
of the transgressing sea.

The age of the Trabuco horizon is not definitely known, since as
yet it has yielded no fossils. Judging from its stratigraphic relations
the formation is probably but shghtly older than the Chico group and
presumably represents some phase of the pre-Chico Cretaceous.

THE CHICO GROUP

Resting with apparent conformity upon the Trabuco formation is
a series of conglomerates differing from those of the lower formation,
in the lighter color of the matrix, in the firmer cementation, in the
greater abundance of pebbles of quartzites and slates, and in the
inclusion of marine fossils in the matrix and in the rounded boulders.
The fossils from the boulders comprise fragments of Jnoceramus and of
an indeterminate gastropod, suggesting the occurrence of earlier
Cretaceous deposits now completely removed by erosion.

The conglomerate resting upon the Trabuco grades upward into
coarse, light-colored sandstones with subordinate strata of hard, fine-
grained calcareous sandstone bearing a characteristic fauna. Follow-
ing these are several hundred feet of laminated, bluish shales, often
containing limestone nodules. The nodules are occasionally fossilifer-
ous. Above the shales the strata again become coarser, being composed
of sandstones, which in places grade laterally into conglomeratie lenses.
These beds are succeeded by a series of alternating strata of sandstone
and shale, which in turn are replaced in the upper portion of the
section by hard, fine-grained, caleareous sandstones, fine tan-colored

142 University of California Publications in Geology [ Vou. 9

shales and lenses of carbonaceous shales, interstratified in places with
seams of coal of an inferior quality.

The most complete section of the Chico group was obtained along
the divide between Santiago and Aliso canons, the details of which
are given below. This section in descending order follows.

SECTION OF THE CRETACEOUS ALONG THE SANTIAGO—ALISO DIVIDE

Estimated

Description of the Lithology Faunal Zones Thickness
Fine-grained, calcareous, tan shales 65 feet
Covered by Vaqueros 120
Tan sandstone intercalated with a resistant, Tellina ooides zone
laminated, micaceous, gray, sandstone 130
Hard, gray, micaceous sandstone 45
Brownish-gray, sandy shales 140
Coarse white sandstone, with a few rounded Turritella pescader-
pebbles oensis zone 60

Light-colored conglomerate, alternating with
bands of gray sandy shale, weathering to

a dark red 200
Fine-grained, steel-gray shale with lenses of
calcareous sandstone 125
Fine-grained gray shale with calcareous nodules 550
Laminated sandstone, slightly conglomeratic, Actaeonella ovifor-
interbedded with gray shale mis zone 50
Gray, conglomeratie sandstone 100
Heavy, gray conglomerates 200
Total thickness of the Chico group 1600

Trabuco formation
Red conglomerates with subordinate bands of

red sandstone 200
Total thickness of the Chico and the
Trabuco 1800
FAUNA

GENERAL CHARACTER

The Cretaceous fauna recently obtained from the Santa Ana Mount-
ains includes eighty species and varieties of Peleeypoda, thirty-three
of Gastropoda, eleven of Cephalopoda, one of Seaphopoda, besides a
few specimens belonging to the Molluscoidea, Vermes, Echinodermata,
Arthropoda and Vertebrata. The entire fauna comprises one hundred
and thirty-one forms, of which twenty-two are new. The fauna from
this region is further increased by other workers who obtained in the
same field a number of species not recognized in our collections.

1916] Packard: Cretaceous of Santa Ana Mountains 143

The bivalves are represented by the largest number of species as
well as by the largest number of individuals of all the groups enumer-
ated above. Trigonoarca, a genus commonly collected in the Trichi-
nopol group of the Indian Cretaceous, is represented in the Santa Ana
Mountains by three new species. Two other genera, Liopistha and
Gastrochacna, have not heretofore been reported from the Cretaceous of
California. Members of the genera Tellina, Crassatellites, Meretrir,
Lima, and Pecten are frequently obtained from the Santa Ana region.

The gastropods are most abundantly represented by members of
the famihes Turritellidae, Aporrhaidae and Volutidae. The Turritellas
are very abundant in this southern region, whereas in more northern
Upper Cretaceous localities of California and especially in Washington
and British Columbia they are rare.

The cephalopods are represented in our collections by a number
of imperfect specimens. Two or possibly three large nautiloids,
resembling certain Indian species, occur in ecaleareous nodules within
the lower shales. Several ammonoids have been found within these
shales. Of these forms the genus Schloenbachia is most commonly

obtained.

FAUNAL ZONES

Faunal studies of marine life carried on within the North Sea,"
at Woods Hole'? and elsewhere show intimate relationship between the
distribution of marine organisms and the factors of their environment.
The character of the bottom, or in geologic terms the type of deposition,
determines in a large measure the facies of a given fauna. Thus the
different types of bottom are characterized by different faunal associa.
tions.

It seems highly probable that under conditions of littoral deposition
a sand-dwelling fauna would be replaced by a quite different fauna
if conditions of sedimentation were changed. Upon the return of
favorable conditions the earler fauna might again occupy the same
region. This effect of the changing conditions is seen in the vertical
distribution of a number of large gastropods belonging to the Volutidae.
These forms are most abundant within the Santa Ana Mountains in

the ‘‘lower’’ shales, and apparently were forced to migrate during

11 Peterson, C. G. Joh., Valuation of the Sea 11, Report of the Danish
Biological Station 21, pp. 1-44, 1915.
12Sumner, F. B., Osburn, R. C., Cole L. J., and Davis, B. M., A biological

survey of the waters of Woods Hole and vicinity, Bull. U. S. Bur. Fish., 31,
pp. 1-860, 1913.

144 University of California Publications in Geology | Vor. 9

the time that certain sandstones were being deposited, appearing again
in the shales above.

Strata that yield a fauna possessing distinctive characters due to
evolutionary change rather than to environmental difference may be
designated a faunal zone. The distinctive character of the zone is due,
then, primarily to the species whose vertical range is restricted to
that zone, and secondarily to those species which having reached their
height of development are often more abundant than at any other
period in the life of the species. The zone may thus be said to possess
restricted and characteristic species, besides many unimportant long-
range forms.

The fossiliferous Cretaceous rocks of the Santa Ana Mountains are
divisible into three zones, each of which will be designated by the name
of a representative species.

The lowermost zone of the Cretaceous of this southern region is
named the Actaeonella oviformis zone from the presence of a very
characteristic gastropod. The fauna associated with this species occurs
in the basal conglomerate and sandstone, which lie below the ‘‘lower’’
shales, representing about three hundred and fifty feet of sediments.
The fauna obtained from these beds is based upon collection made at
the following University of California loealities : 2130, 2131, 2134, 2139,
2140, 2141, 2142, 2143, 2191.

This zone is characterized by the abundance of Actaconella ovi-
formis, which appears to be restricted to the zone and by Pecten oper-
culiformis, Pecten californica, Trigonoarca, n. sp.c and Astarte, n. sp. a
which are occasionally collected within the higher zones although they
are nowhere so abundant as within these lower beds (see Table 1).

The faunal zone above the Actaeonella oviformis zone is named
after its most characteristic species, Turritella pescaderoensis Arnold.
The strata through which this fauna ranges include about eleven
hundred feet of shale, sandstone and conglomerate.

This zone includes two faunas which are distinguished mainly by
characters due to differences in bathymetric conditions. The shales
just above the basal conglomerate and sandstone yield a number of
gastropods and cephalopods not found abundantly in the coarser sedi-
ments of the underlying or overlying strata. This deeper-water fauna
appears to be replaced by a fauna of shallower water characterized
by the abundance of such species as Turritella pescaderoensis, Crass-
atellites lomana, and C. conradiana var. tuscana, but it again appears
in a slightly modified form in certain higher shale beds. This deeper-

1916] Packard: Cretaceous of Santa Ana Mountains 145

water faunal phase is best represented at the following University
of California localities: 2136, 2147, 2153, 2156, 2166, and 2170.

The deeper-water phase of the Turritella peseaderoensis zone is
noteworthy for the number of species of the Volutidae and Aporrhaidae
that it contains. Opis triangulata commonly occurs in the shales at a
horizon about the middle of this zone. Several poorly preserved am-
monids and nautiloids oeeur more abundantly here than elsewhere.

The shallower-water phase of the Turritella pesecaderoensis zone
replaces in part the fauna from the shales below. The strata through
which this assemblage ranges comprise about six hundred feet of
sandstones, heavy conglomerates, and occasional subordinate bands
of shale. The following University of California localities have been
selected as being characteristic of this phase of the Turritella pes-
caderoensis zone: 2135, 2146, 2148, 2150, 2151, 2152, 2159, 2160, 2162,
2167, and 2172. Crassatellites lomana and C. conradiana var. tuscana
together with Turritella pescaderoensis form a large proportion of the
fauna of a fossiliferous stratum that is traceable for a distance of
several miles.

The uppermost zone is known as the Tellina ooides zone. The
fauna is characterized by the great abundance of specimens of T'ellina
and occurs within the uppermost three hundred feet of the section.
The strata consist primarily of fine-grained sandstones. The fauna
from these upper beds is imperfectly known, due to the concealment
of much of this part of the formation by the overlying Vaqueros.
The fauna of this zone listed in the table below was obtained from the
University of California localities 2168 and 2169.

This zone yields a large number of pelecypods and relatively few
gastropods. The lack of cephalopods is noteworthy, especially since
fragments of ammonites are frequently collected in the beds below
this horizon. Perissolax brevirostris is quite characteristie of the zone.
Meekia sella was found only within these uppermost beds, although it
has been reported elsewhere from the lower Chico.

The fauna of the different zones is indicated in the table below.
A fifth column is given for those species whose stratigraphic position
is unknown. An asterisk indicates species characteristic of the zone

in which this convention appears.

146 University of California Publications in Geology [ Vou. 9

TABLE I

LIst OF CRETACEOUS SPECIES FROM THE SANTA ANA: MOUNTAINS

o = ° Ww a! oD
ce Cec) Ee Be
ce beta fo23 § at
$& G4be Sgke fe #8
<8 Afes nEES ES NE
Acila truneata (Gabb) -....202220..2----- x x x z
AVAGO (CE) pany co coee vo oer etere esters eeee sees x :
Anomia-lineata Gabb. ............-2..2..2-.---- x : x
AVSTOT UC) Ms SPs, cece cee nnscecerense care eeseeere zm x x ee ats
PAS Gar GOS MES) a. O erccecesecs-seescsesecseeeaeseceeneees = oes ee = x
Astarte, sp. ¢ sacs See a a x
Cardium, sp. a x
Cardium, sp. b x -
Cardium, sp. ¢ x
Cardium, ef. remondianum Gabb ........ x = 3
Clisocolus dubius (Gabb) ..............-.---- x os x x
Corallliochamay Spe cotccceceececee eeeeee es ee se ae — x
Corbula traskii Gabb ...................-..--.--- x ?
Crassatellites lomana (Cooper) .......- oe x
Crassatellites conradiana, var. tus-

(hse (Cie!) 0) 0) saya epee eee x x * x
(Cquverndllleverey at (yo), (0), Agence eee eee un Be ee Be x
Gunculllae ays Spor Dy ceececceeeeteeeee paces -eeene x a ee ae
Cucullaea truncata (Gabb) -.............. x x x x
Cucullaea decurtata (Gabb) .............. x mee ?

Cucullaea ponderosa W hiteaves .......... = eee are ne x
Dosinia inflata Gabb . x x ?
HEIKO D2y Tas We SPs le ctecerecee-cceescsereetes;eveceese ic ~ =e

DDD: 0} aA ct) OA) cee cE ia x x see =
GialStrochaemay ws ieecesscesceereceeeeesseee steers a PR: whe ae x
Glycymeris pacificus (F. M. Anderson) =X

Glycymeris veatchii (Gabb) .............. x Xx x x

IER OMMO MY Ase My SPs) eer cereeeeeseeeeeessereeeeewee x

Inoceramus, ef. digitatus (Sowerby) x :

TOC CM AINUIS SY) ceee2ee eect ces coee nee = ce eeeeese eee ose cscs agse sabe x
Inoceramus whitneyi Gabb ................ = se wt aioe x
TSO CANIS (SPs vesc:125- 251d. stexecensecveccsegeecseeess x 2k ee

dBase )ORs) eee eres sc teres See eee i: =e a x

DDFa 0: at] 0 ees lee ee ze cts eats fess x
JWahorkeh sealierdoy valle) (CW 0) 0) cesses esse noe ae sous — x
Lima, ef. shastaensis Gabb —.....-....---...- x es ae — =
Liopistha anaana (F. M. Anderson)..... x soc3 = ae ois
Martesia (?) parvula Whiteaves ...... seb = sass x

Meekia sella Gabb ..................---- =) es — as x
Meretrix arata Gabb xX

Mieretrix Tenis \Gialbio) ici2ceseecccs-coceeceeeeeeee x wos x x
Meretrix nitida Gabb x : x x :

1916]

PELECYPODA—

Meretrix, sp. a
Meretrix (?) sp. b

Packard:

TABLE I—(Continued)

Modiolus siskiyouensis Gabb ............--

Modiolus, sp. a

Mytilus, sp. ............-

Nemodon vancouverensis (Meek)......

Opis triangulata (Cooper)
Ostrea, n. sp. @ .....-..--

Ostrea, n. sp. b

Ostrea, n. Sp. ¢ ....-.---
Ostrea breweril Gabb
Panope, n. sp. @ .......-

Pecten californicus Gabb ...................-
Pecten operculiformis Gabb ..............

Pecten, sp. @ .......:...-.-
WRCCtem. Spa 0) seers e-=
Pecten (?), sp. ¢ -.....

Pinna, ef. calamitoides Schumard ......

Plicatula, n. sp. @ ...
Siliqua, n. sp. a@ ........

SolenseS piss.

Spisula ashburnerii (Gann) oo eee
Spisula chicoensis Packard ............-...
Spisula gabbiana (F. M. Anderson)

Spondylus, sp.

Spondylus, n. sp. a -

. Tellina, n. sp. a
Tellina, n. sp. b

Tellina, ef. hoffmanniana Gabe meget

Mellana, SP: -:-2s-c--2--
Mellimassped@ 2-2-2
Tellina ashburnerii Gabb .
Tellina ooides Gabb
ened OyeS pogo eases
Trigonoarca, n.sp. a

Trigonoarea, n. sp.

lb ere eee ee rere ere
Trigonoarea, n. sp. ¢

Trigonia evansana Meek ...............-...-
Trigonia tryoniana Gabb ..............-....-

GASTROPODA—
AGMACA, ‘SPie--:.2---=--
Actaeonella oviformis Gabb

Actaeonella
oviformis zone

Deep water
phase of
Turritella pesca-
deroensis zone

x

Shallow water

Cretaceous of Santa Ana Mountains

J
oO
oA o
aS =
GI °
wae °
8g s
ore =I
nHeS = @
gb BE
AAs BS
x x
x
x
x
x
*
x
x
x oe
x
x
*
x
x
x
x
x x
x
? :

147

Zonal position
uncertain

Me PO OK Kes

148 University of California Publications in Geology [ Vor. 9

TABLE I—(Continued)

g 2 w g e n a
Bo sud2 7.82 8 ge
68 povet FoR 3 as
42 Ases as65 88 85
Alaria condoniana (F. M. Anderson) x 2 as ers 2
Alaria faleiformis (Gabb) ..............-. x : ee
Amauropsis, 1. SP. Q. ....2.-2.-2002202022e2-- x x bee
Amauropsis oviformis Gabb .............. x x tae nee
Aporrhais, n. sp. a x eee
Aporrhais, n.sp. b . x eee
Aporrhais, n.sp. ¢ x 23
SPS ail ea ay Whey SJ pee x =
KOCchph el auibbree only (pO Ch ane nee eae ae ae see = x
KCCor aT NSUA NY OH eee ery eee =e a ae an x
Cinulia obliqua Gabb 2.2.2.2... = me x y
Chrysodomus, sp. a x 5 ee
Epitonium, n. sp. a x e
B Dpu koa: es 29 0 peepee ree eee a meee eer eS ee ae oe x
SETS US (29) nS [ey Cleeence eee eens eee eeeee pe A eae = x
TANVESTETS Ye GED 15 4) On) opps eee epee reste ore errr x
Gyrodes expansa Gabb .............-........-- x x 5 wate
Tinsyaredie a (G2) Messe sereen eee x » :
Lysis (?), n. sp. a ee x A
Margarites ornatissima (Gabb) ........ ee _— 3 EP x
UNECE SS Pip ec es nse cae easae eon ceeseeeecners = ois x
Perissolax brevirostris Gabb ............ =e ave = x
TEAOeEW a sBMG Wetsh YS] Os eee ee ee ec — ae oe Sere x
Turritella, n.sp.a - x .
Murritella, mn. Sp. 0) 222 se eos seccceesnseee--te= x
Murritelay SPC) s:-ssessecvs.saccherseeseeeesesccoes = eee a eece x
Mammut ella VS die csatece-cee ee nseeere eee eee x ee ee a Be
Turritella pescaderoensis Arnold ...... x x = x sess
Woluto derma, iS). soos aera i cece
Volutoderma, n. sp. b x e
Volutoderma, n. sp. ¢ = 3 ma
Volutoderma, ef. californica Dall ...... ae aan x See zee
ScaPHOPODA—
ID Yess eV WENA, {9 0)s eee enero errr a ee oe are x
CEPHALOPODA—
PASM OMY CS91S [ears nce ee eret= trace narseneeeece=s x cet
/Noaahaakopaln dels) 0 ake eee eee ene x Se
PAGINITIN OTC C Sot [et Geese ea nce nner eeeeeereerecences x :
Ammonites, sp. @ ......--.------------ SG A
Baculites chicoensis (Trask) -............- Ses a x ae =
Hari tie Sig G30) ieesmess = seeeeeeee ee ceeeteeeeseo nese “ek ee x ae ae

Ielicamcyls; Spey cescccn-seecccesecerseeeeseaeeee x aoe sc aie ence

1916] Packard: Cretaceous of Santa Ana Mountains 149

TABLE I—(Contimued)

z e
o o ry o
= mee EE g
a H Bg Ss XS as} S
Za 8 82 F Bx 8 Ze
Sh bese Eese a ae
25 ages S8ne ai
go FEE GHEE g2 2:
fe aoa vo cs
a3 Aaas Daas aS Ns
UN etal SiS) 10 cee -cees. cecseeneee- veces eee. cece x
DN ental S9SYp- (Oi esse cceeces ec zecsence ces-ceeececas sec=te x
Placenticeras californicum F. M. An-
GETS OM oe ee cca Bee aes poe —_ x
Schloenbachia knighteni F. M. An-
LETS O perce caccse ese cee a ences eee ats ae i= aie —_ srt x
ASTEROIDEA—
Ophioglypha, n. sp. @ .......2..-2.2.0-.0-- ae a = oes x
ECHINOIDEA—
Schizaster,. mM. Sp. @) .2.s2esceeccceeec eee x
BRACHIOPODA—
Merebratulay Spi. c2-.seceseee wets eatseceseucssezes x
VERMES—
AYV/Coy e001 pb OXsfsh See eee ere = enn eS eon ae _ as x
CRUSTACEA—
(Oh KOC Ey ee x
PISCES—
GATES Ds cesesee sass cas ncseeean se ete ene en ceve eee arts — sae x

To this list may be added the following species that have been
reported by Bowers,'? Cooper,’* and Anderson’ from the Santa Ana
Mountains. The stratigraphic situation of these forms is uncertain.

Asaphais multicostata Gabb Globiconcha remondii Gabb
Clisocolus cordatus Whiteaves Potamides tenuis Gabb

Crenella santana Cooper (?) Scobinella dilleri White

Cucullaea bowersiana Cooper Turritella seriatim—granulata Roemer
Cucullaea inermis Gabb Acanthoceras compressus F. M. An-
Pecten traskii Gabb derson

Pholadomya sonorensis Gabb Ammonites stoliczkanus Gabb
Cominella lecontei White Ammonites traskii Gabb

Fulgar hilgardi White Baculites fairbanski Anderson

13 Bowers, Dr. Stephen, Orange County, 10th Annual Report State Mineral-
ogist, California State Mining Bureau, p. 399, 1890.

14 Cooper, J. G., Catalogue of California Fossils, California State Mining
Bureau, Bull. 4, pp. 38, and 36-51, 1894.

15 Anderson, F. M., Cretaceous Deposits of the Pacifie Coast, Proe. Calif.
Acad. Sci., Third Series, Geol., vol. 2, pp. 27-32, 1902.

150 University of California Publications in Geology | VoL. 9

Desmoceras sugatum (Forbes) Placenticeras pacificum J. P. Smith
Lytoceras jacksonense F. M. Anderson Schloenbachia knighteni Anderson
Nautilus texanus Schumard Terebratula abesa Gabb
Placenticeras californicum F. M. An-

derson

The relationships of the above defined zones are shown in summary
in Table IT.

TABLE II
Actaeonella Turritella pesca- Tellina Chico
oviformis deroensis zone ooides Creek
zone zone fauna
Deep Shallow
water water
phase phase
Number of forms ..................22.----- 65 25 41 26 79
Number of determined species ..... 47 16 28 18 79

Number of determined species ap-

pearing in the Actaeonella ovi-

OTM) Z OME eee sresceeeceseereseeee teres se 47 1] 18 4 12
Number of determined species ap-

pearing in the Turritella pes-

caderoensis zone. Deep water

DH AS Cs caeec ee eet ecreeere eee 11 16 13 7 6
Number of determined species ap-

pearing in the Turritella pes-

caderoensis zone. Shallow

WeLU CT as MeyS Ggeeeecceereeee cee ceases 18 13 28 12 16
Number of species appearing in

the Tellina ooides zone ............ 4 7 12 18 17

RELATION TO OTHER CRETACEOUS FAUNAS OF CALIFORNIA

Anderson recognized the Chico affinities of the fauna obtained in
Silverado Canon on the western slope of the Santa Ana Mountains,
but more recent collecting has revealed a large number of species as yet
unknown from the typical Chico of northern California. The majority
of the forms peculiar to the southern fauna occur in the lowermost
beds of that region, suggesting that this stage represents a lower
horizon than that known at Chico Creek. This raises a question as to
the definition of the beds of the Chico and also as to reasons for the
difference between the faunas of the Chico and the Santa Ana
Mountains.

In considering the relation between the faunal stages of the typical
Chico and the Cretaceous of the Santa Ana Mountains it is necessary
to review briefly the relationships of the Chico fauna of Shasta and
Tehama counties to that of the underlying Horsetown.

1916] Packard: Cretaceous of Santa Ana Mountains 15]

The apparent conformable sequence of beds of the Shasta-Chico
series as exposed on Elder and Cottonwood Creeks in Tehama and
Shasta counties, together with the recognized faunal continuity make
the definition of the different groups difficult. Diller and Stanton
who have most carefully considered this question make the following
statement: ‘‘The faunas of adjacent beds, however, are so bound
together by many common species that there is no palaeontologic
break anywhere within the series.’’?®

The Knoxville may for the purposes of this paper be defined in
the words of Stanton as ‘‘the Aucella-bearing Cretaceous beds on the
Pacifie Coast of the United States.’"7 No specimens of Auwcella have
been reported from the Santa Ana region and therefore this phase of
the Cretaceous need not be discussed further.

The Horsetown was first defined in a paper by Charles A. White
entitled ‘‘Notes on the Mesozoic and Cenozoic Palaeontology of Cali-
fornia.’’** On page 19 of this paper he writes:

I shall therefore, for the present, retain the name Shasta group in the
general sense in which it was used by the geologists of the California survey;
but for purposes of convenience in references which I must necessarily make
in this article to those divisions, I shall designate them as the Horsetown beds
and the Knoxville beds, respectively. These names are suggested by the
localities from which the best collections of fossils of each division were
obtained.

On the next page he states regarding the fauna: ‘‘It is especially
rich in Cephalopoda, as will appear by referring to the California
reports, where the fossils of this division are recorded as coming from
‘“‘The North Fork of Cottonwood Creek, Horsetown, ete.’’ <A few
sentences below this White lists thirteen of Gabbs’ species which he
would exclude from the Horsetown because of their occurrence at
doubtful Horsetown localities. Five of these, Potomides diadema
Gabb, Ringinella polita Gabb, Liocium punctatum Gabb and Lima
shastaensis Gabb are later reported by Anderson'® from the Horsetown,
although their occurrence is not definitely given. It thus appears that
the type section of the Horsetown beds includes beds of the Shasta

16 Diller, J. S. and Stanton, T. W., The Shasta-Chico Series, Bull. Geol. Soe.
Am., vol. 5, p. 464, 1894.

17 Stanton, T W., The Fauna of the Knoxville beds, U. 8. Geol. Surv. Bull.
133, p. 12, 1895.

18 White, C. A., U. 8S. Geol. Surv. Bull. 15, pp. 19-20, 1885.

19 Anderson, F M., Cretaceous Deposits of the Pacific Coast, Proe. Calif.
Acad. Sci., Third Series, Geol., vol. 2, p. 41, 1902.

152 University of California Publications in Geology [ Vou. 9

group recognized by the California Survey and exposed on the North
Fork of the Cottonwood Creek and at the locality at Horsetown. In
1888 Diller and Stanton”? state:

At Horsetown and Texas springs, however, only a few miles northeast of
the Cottonwood section, many fossils have been found that evidently belong
very near the top of the Horsetown beds. Lists of species from these localities

showing a commingling of the Horsetown and Chico faunas have already been
published.

Yet in 1901 Stanton is quoted by Merriam”! in regard to a John Day,
Oregon, fauna to the effect that

A similar fauna, with some additions, occurs in the sandstones at Texas
Springs and near Horsetown, Shasta County, California, and has been regarded
as proof of the blending of the Shasta and Chico faunas, partly because the
beds at Horsetown had long been thought to belong to Gabb’s Shasta group and
had even given the name, Horsetown beds, to the upper division of the Shasta.
It is evident, however, from White’s somewhat vague definition of the Horse-
town beds, that the term was meant to include the strata immediately above
the Knoxville that contain the fauna so well developed on the north fork of
Cottonwood Creek, in the neighborhood of Ono, and which really has no close
relationship with this basal Chieo fauna of Texas Springs, Horsetown, and
elsewhere.

As far as the writer is aware, this phase of the Shasta—Chico problem
has not been discussed elsewhere.

Such an interpretation is in accord with an earlier statement made
by Diller and Stanton*’ to the effect that the Chico beds extend from
‘‘a short distance above the mouth of Hulen Creek to Gas Point,’’ for,
in the writer’s opinion, the fauna from the loeality on Hulen Creek is
very closely related to the one near Horsetown, but it is not considered
that these represent Chico faunas.

The strata at the Hulen Creek locality just above its confluence
with the North Fork of the Cottonwood are composed of conglomeratic
sandstones lying apparently conformably upon sandy shales, which but
a short distance stratigraphically below contain a typical Horsetown
fauna. These psephitie strata grade above into shales similar to those
just below. These upper shales grade upward into a massive con-
elomerate of several hundred feet in thickness which outcrops in the
gorge just below the junction of Hulen and Cottonwood creeks. These
conglomerates have yielded the writer no determinable fossils. The
~~ 20 Diller, J. S., and Stanton, T. W., op. cit., p. 445.

21 Merriam, John C., A Contribution to the Geology of the John Day Basin,

Univ. Calif. Publ. Bull. Dept. Geol., vol. 2, pp. 283, 284, 1901.
22 Diller, J. S., and Stanton, T. W., op. cit., p. 444.

1916] Packard: Cretaceous of Santa Ana Mountains isis}

base of these beds just below the mouth of Hulen Creek might well
be taken as the base of the Chico group. This apparently agrees with
White’s original idea of the location of the base of that group judging
from the fauna obtained above and below the horizon.

The differences of opinion as to the location of the base of the
Chico group tend to substantiate the view of Diller and Stanton?”
regarding the stratigraphic continuity of the Shasta—Chico series. and
show the necessity of detailed faunal studies within this region before
the Horsetown and Chico faunas can be clearly defined. Regardless
of the final decision on this point, it seems advisable for the purposes
of this paper to consider the fauna obtained at Horsetown and its
correlative on Hulen Creek as uppermost Horsetown.

In compiling a list of Horsetown species for comparison with the
fauna from the Santa Ana Mountains only those species have been
included that are known to have come from the Horsetown beds as
defined above. Such a procedure considerably reduces the published
Horsetown fauna.

A comparison of such a list with the faunal lst from the Santa
Ana Mountains reveals the following species in common: Cucullaea
truncata Gabb, Nemodon vancowverensis (Meek), Trigonia evansana
Meek, Pecten operculiformis Gabb. These species have a long range,
occurring in the Chico of Chico Creek. From this very small repre-
sentation of common forms it would appear that the latter fauna is
not the equivalent of the Horsetown as it is now imperfectly known.

The term Chico was first used by Gabb in a paper read before the
National Academy of Sciences in August, 1868.24 The type locality
as designated by Gabb in the Palaeontology of California?’ is very
indefinite, including beds most extensively represented in Shasta and
Butte counties, California. The group was named for Chico Creek,
along which a number of fossiliferous localities occurred.

Recent studies made by C. K. Studley show that the three fossilifer-
ous localities on Chico Creek contain faunas so closely related that they
may be considered as a unit.2° The faunas already published by
Gabb**? and Turner** have been greatly increased through the collec-

23 Op. cit., p. 464.

24Gabb, W. M., Palaeontology of California, vol. 2, p. xii, 1869.

25 Op. cit., p. xii-xiv.

26 Studley, C. K., MS thesis, University of California, 1914.

27 Gabb, W. M., Palaeontology of California, vols. 1 and 2, 1864-1899.

28 Turner, H. W., The rocks of the Sierra Nevada, Fourteenth Annual Report
U.S. Geol. Surv., pt. 2, p. 460, 1892-1893.

154 University of California Publications in Geology [ Vou. 9

tions made by Mr. Studley. The two published lists supplemented
by Studley’s list are taken as the basis of comparison with the fauna
from the Santa Ana Mountains.

A comparison of these faunas reveals the following species in
common between Chico Creek and the Santa Ana Mountains:

Acila truneata (Gabb) Spisula chicoensis Packard
Anomia lineata Gabb Spisula gabbiana (Anderson)
Clisocolus dubius (Gabb) Tellina ashburnerli Gabb
Crassatellites conradiana, var. tus- Tellina hoffmanniana Gabb (?)
eana (Gabb) Tellina ooides Gabb
Cucullaea truneata (Gabb) Trigonia evansana Meek
Dosinia inflata (Gabb) Alaria faleiformis (Gabb)
Glyeymeris veatchii (Gabb) Cinulia obliqua (Gabb)
Inoceramus whitneyi Gabb Gyrodes expansa Gabb
Meekia sella Gabb Perissolax brevirostris Gabb
Meretrix lens Gabb Volutoderma californica Dall
Meretrix nitida Gabb Baculites chicoensis Trask

Spisula ashburnerii (Gabb)

The number of species in common between the Santa Ana Mount-
ains and Chico Creek represent but about thirty-one per cent of
the number of determined species of the southern fauna, being nearly
the same per cent of the Chico Creek fauna. This small per cent of
identical species from the two localities is due in part to the fact
that the southern fauna, composed of three faunal zones, is compared
with the fauna from Chico Creek, represented probably by a single
zone. Seventeen out of the eighteen described species from the Tel-
lina ooides zone of the Santa Ana Mountains appear in the above list
of common species. On the other hand, there are but twelve out of
twenty-eight described species from the Aetaeonella oviformis zone
of the southern fauna occurring at Chico Creek.

The much larger number of species in common between these
localities than was noted above in the comparison with the Horsetown
fauna indicates that the southern fauna is equivalent to at least a part
of the Chico from Chico Creek.

The faunal differences may be more apparent than real, for the
fauna from Chico Creek is but imperfectly known and will be un-
doubtedly increased by subsequent workers. Nevertheless the differ-
ences demand consideration.

It appears to be the consensus of opinion that differences of tem-
peratures due to the geographic positions of these two localities were
not as great during the Cretaceous as at present. This factor would

1916] Packard: Cretaceous of Santa Ana Mountains 155

therefore have had but little weight in determining the character
of the Chico faunas. Temperature would be a factor in so far as it
was associated with oceanic currents, the courses of which are deter-
mined largely by the distribution of land and water.

There appears to be little evidence that salinity played an im-
portant role in determining the peculiar features of these two faunas,
for neither in the Santa Ana Mountain basin nor in that of the
Sacramento Valley do we find indications of brackish-water conditions,
except very locally during comparatively short periods of coal
formation.

The direct and indirect effect of the type of the bottom is a
generally recognized factor influencing the life upon the floor of the
sea. A comparison of these basins of deposition reveals the fact that
the strata of the more southern one are more conglomeratic than are
those of the northern basin. The fauna as well as the lithology
indicates that the Cretaceous beds of the Santa Ana Mountains were
deposited largely within shallow waters. The species types from Chico
Creek and the considerable amounts of carbonaceous material also
argue for shallow-water conditions within the northern basin. It thus
appears that the faunal differences can not definitely be attributed
to differences in the character of the bottom. However, to a collector
of Recent Mollusca this may not appear very conclusive, for quite
diverse faunas exist under present conditions on types of sediments
in which after induration the differences would probably not be par-
ticularly marked.

The areal extent of the Upper Cretaceous sea is such as to suggest
that there was direct communication between these two basins of
deposition. If this is a correct inference, isolation did not play an
important part in causing the faunal dissimilarities.

The differences in environment, then, resolve themselves primarily
into the effects of temperature due to oceanic currents, and possibly
to differences of types of sediments. These all directly or indirectly
were affected by the distribution of land during this period. That
the shore line during the Upper Cretaceous was only a short distance
east of the present summit of the Santa Ana Range is inferred by the
type of sediments composing the Chico group of this region, and by
the absence of Chico strata at any considerable distance east of those
mountains. The Trabuco formation and the lower part of the Chico
have been described above as being decidedly conglomeratic, both
containing boulders apparently derived from rocks similar to those

156 University of California Publications in Geology [ VoL. 9

comprising the core of the present range. The character of the contact
of the Trabuco formation with the basement complex, as shown in
detail and by areal mapping, indicates a land surface of low relief,
but the character of the sediments contradicts this in a measure, for
streams of considerable gradient must have existed in order to have
transported the coarse sediments characterizing these strata. This
apparent conflict may possibly be reconciled upon the assumption of
a rather narrow coastal plain, adjacent to a mountainous country of
considerable rehef. If no land existed west of this shore-line, as seems
probable, the physical environment of this region differed considerably
from that of the present Sacramento Valley region.

The Upper Cretaceous beds of northern California were deposited
in an inland sea protected from the open ocean by an archipelago,
occupying the region of the present Siskiyou Mountains and the
northern end of the Coast Ranges. Regarding this Diller and Stanton
say

The attenuation of the Shasta—Chico Series westward from the Sacramento
Valley and the overlapping of the newer beds upon older crystalline rocks of
the Coast Range shows that the Coast Range was formed before the deposition

of the Shasta—Chico series, and probably at the close of the Jurassic when the
Mariposa beds were upturned.29

Such a distribution of land might have had a marked effect upon
the local oceanic currents, thereby producing temperature differences
sufficiently great to account in part for the faunal dissimilarities noted
above. Such a factor accompanied by others of lesser rank, concerning
which but little is as yet known, is perhaps of sufficient importance
to make it unnecessary to consider that the faunal peculiarities of the
Santa Ana Mountains and northern California basins of deposition

are due solely to different faunal stages.

RELATION TO FOREIGN CRETACEOUS FAUNAS

Various writers, including Gabb, White, Smith, Stanton, Hamilton,
Whiteaves, and Anderson, have expressed opinions regarding the
equivalents of the Chico group. This problem is complicated; there-
fore, only a few of the more recent, views upon this subject will be
considered in this discussion.

Anderson, following in part the conclusions of Gabb and Whit-
eaves, considered that ‘‘the Chico, the Nanaimo, and the Phoenix and

29 Diller, J. S., and Stanton, T. W., op. cit., p. 464, 1894.

1916] Packard: Cretaceous of Santa Ana Mountains 157

Henley beds may be shown to be homotaxially equivalent, and equiv-
alent also to the beds of the Colorado group in the interior basin.’’*°

Anderson gives parallel lists of identical or closely related species
found in the Chico and the Island of Ezo. His view of the relation-
ships of the Chico to the European Cretaceous is best expressed in
his own words:

On the whole, however, the strongest affinities are undoubtedly with the
Turonian; and if one remembers the great stratigraphical range of some of

the species of the Sacramento Valley, it does not seem remarkable that
Cenomanian or even Gault types are found oceasionally in the Chico.31

A correlation table shows that Anderson considered the Chico as in-
eluding the Arrialon, Trichinopoli and a part of the Ootatoor groups
of Southern India.*”

Stanton** takes issue with Anderson regarding the geographic
relation of this western fauna to that of the interior basin.

Whiteaves and F. M. Anderson have argued for a connection during Chico
time between the Pacific and interior seas, but the evidence brought forward
in support of this view is based upon types that have a world-wide distribution
and on those that are only similar, not specifically identical. In my opinion
direct connection has not been proved.

Stanton believes, however, that the Chico began a little earlier than
the Colorado group, including all of the Colorado and continuing a
little longer than that group.

These citations are sufficient to indicate the major problems involved
in the correlation of the Chico with beds outside of the Pacific Coast
region. Further discussion of this problem will be considered in a
future paper.

AGE

The Cretaceous beds of the Santa Ana Mountains yield a fauna that
is more closely related to that from Chico Creek than to the fauna from
the Horsetown beds. The relationships of these faunas are shown in
the following table, in which there is indicated the number of species
from the southern fauna common to these northern faunas as defined
above.

30 Anderson, F. M., Cretaceous Deposits of the Pacifie Coast, Proe. Calif.
Acad. Sei., Third Series, Geol., vol. 2, p. 57, 1902.

31 Op. cit., p. 62.

32 Op. cit., p. 62.

33 Stanton, T. W., Later Mesozoic Invertebrate Faunas, in Outlines of Geo-
logic History, Willis and Salisbury, p. 190, 1910.

158 University of California Publications in Geology [ VoL. 9

TABLE REPRESENTING NUMBER OF SPECIES FROM CRETACEOUS OF SANTA ANA
MOUNTAINS KNOWN ALSO IN HORSETOWN AND CHICO

Horsetown Chico Creek
Number of species of Pelecypoda a 19
Number of species of Gastropoda ... 5
Number of species of Cephalopoda 2 1
Total number of species in common. ............ 4 25
Per cent of species in common. ..................-- 5 31

The small percentage of typical Chico species represented in the
southern fauna is due in part to the fact that the fauna from the
Actaeonella oviformis zone is undoubtedly older than any horizon thus
far reported from Chico Creek. This lowermost fauna is more closely
related to the fauna from the beds immediately overlying the Horse-
town group in Shasta and Tehama counties than to the type Chico. If
the term Chico is made to include the known Cretaceous faunas of
California that are younger than the Horsetown fauna as previously
defined in this paper, the fauna from the Santa Ana Mountains may
be properly designated as Chico. Such a procedure does not conflict
with the generally accepted, though rather vague definition of the
Chico. It thus appears that the type Chico in the restricted sense
represents, as was pointed out by Anderson, but a portion of the Upper
Cretaceous column of California.

SUMMARY

The Cretaceous strata of the Santa Ana Mountains are divisible
into at least two groups. The lowermost one, consisting of about
two hundred feet of red, non-fossiliferous conglomerates and sand-
stones, is here designated as the Trabuco formation. |Conformably
overlying these beds is a series of conglomerates, sandstones, and
shales aggregating about two thousand feet in thickness, which have
yielded a rich invertebrate fauna.

The Cretaceous fauna from the Santa Ana Mountains has certain
affinities with that of the uppermost Horsetown beds but is much more
closely related to the fauna from the Chico of Chico Creek. The small
per cent of typical Chico species represented in the southern fauna
is due in part to the fact that the fauna from the lowermost beds of
the Santa Ana Mountains is undoubtedly older than any fauna thus
far reported from Chico Creek, and also due in part to environmental
differences resulting from the distribution of land on this Coast during
the Upper Cretaceous.

1916] Packard: Cretaceous of Santa Ana Mountains 159

Three faunal zones have been recognized in the Cretaceous of the
Santa Ana Mountains. The lowermost, the Actaeonella oviformis
zone, yields a large fauna which is older than that from the type Chico
on Chico Creek, but younger than that of the uppermost Horsetown.
The second, or Turritella pescaderoensis zone, possibly represents a
part of the Chico known at Chico Creek; while the uppermost, the
Tellina ooides zone, yields a fauna that is certainly ineluded in the
typical Chico.

Transmitted April 9, 1915.

eeeennnnee

a : lifornia, by Louise peeet:
from Late Cenozoic Beds of the Pacifie C

Monterey Series in California, by George Davis Louderback i
ee Notes on Fossil Sharks, by David Starr Jordan and rey Hugh Beal ..

Votes. on Seutella norrisi and Seutaster peer cout by Robert W. Pack wa ROME Ny 5e
he Skull and Dentition of a Camel from the Pleistocene of Rancho La Brea, by
_John CO. Merriam .......--cessceenecesteeceecenneeneeeecceecnoncatesenneesconenenneennnecanaceenaeesacsennnesenscsenseetas — 20c

TG st ala oa RR i ie Olen ea Ane POR Ree eRRRe eee POMS Ketan st Be
Nothrotherium | and Megalonyx from the Pleistocene of Southern California, by ay
TOSSES COC Le cee ee a eR Oe NS a NS ee Sa a eee e loer mat)
‘Notes on the Canid Genus Tephrocyon, by John ©. Merriam ........-ssescssccssecceecreeeee IQ
Vertebrate Fauna of the Orindan and Siestan Beds in Middle California, by J oie i nt
MMR Tu etic ec a Pr Re fe ain EE ce Me en, hes LO ct eae
Recent Observations on the Mode of Accumulation of the Pleistocers Bone Deposits i
SeOLehancho Wa Brea, by Reginald CO. Stomer ._222...ctesacscvc-nctectsntsveodoctceapeecessn-saeshaeckcoareee as m 0c a
‘21, Preliminary Report on the Horses of Rancho La Brea, by John C. Merriam autmectaus BOG aa
; New Anchitheriine Horses from the Tertiary of the Great Basin Area, by John Ors are
BIUES Lea UI epee so oe Stee eina stb wake acesteecteoasdecbaceusoas venect Sovapttt- «ua gedUanavadsusrscsapteceae coemmnenaae >, del

New Protohippine Horses from Tertiary Beds on the Western Border of the Mohave

Toasts Ting Bihan (OEMS wet haa) ORO a ea ave meme A Ria een p Aer neice NOE de
Pleistocene Beds at Manix in the Eastern Mohave Desert Region, by John P.
TES TIGL SAS aa a eS SO PE SY ane eR Me Oe mne end Be eC 25¢
The Problem of Aquatic Adaptation in the Carnivora, as Illustrated in the Oste- aaa

— and Evolution of the Sea-Otter, by Walter P. Taylor ...........2..2--c--c:-ceseereeeeeeee 30e°

VOLUME 8.

Is the Boulder ‘‘ Batholith”’ a Laccolith? Problem in Ore-Genesis, by eater :

a oN Vitec ee i a a ee ee ce be SAY YS 25¢

Note on the Faunal Zones of the Tejon Group, by Roy EH. Dickerson Cr

eth of a Cestraciont Shark from the Upper Triassic of Northern California, by

Bhairrg lla! (Che LSet 3 "ae at ae Sl eg Doe ea ee ee es ee AIS BYOM
Bird Remains from the Pleistocene of San Pedro, California, by Loye Holmes Miller. 10¢

Tertiary Echinoids of the Carrizo Creek Region in the Colorado Desert, by William
Sa TEEN onogeocest asec oc eee Ee ace irae eee aeepe ee com eee are aes epee ch eee reed ee

Fauna of the Martinez Eocene of California, by Roy Ernest Dickerson

Jescription~ of New Species of Fossil Mollusca from the Later Marine Neocene One", See

eMmetmaiars bye bcuce: Martini: cece eS cee: co Seas te ceo. ack, shee. ew) eee ee a . 20¢

The Fernando Group near Newhall, California, by Walter A. English... Sepa leya.

. Ore Deposition in and near Intrusive Rocks by Meteoric Waters, by Andrew €> > ane:
Lawson ..... Se Pei at, Se a ee a ee, Sos Pe aT Soeee sete, | scat eRe co nn eee ER I 20¢ —

e Agasoma-like Gastropods of the California Tertiary, by Walter A. English... 15¢ —

e Martinez and Tejon Eocene and Associated Formations of thes Santa Anmaa a sey
Mnneapeins by NOW. Eis DIC KeTSOM. Lice coo os acsessek ot d Stews ce an ceo nese cal cae ee a ~20¢- )
he Oceurrence of Tertiary Mammalian Remains in N pitlienstomt Nevada, by J: ohn Prag
Ra ee ie RE kN So as a ea 10¢
Remains of Land Mammals from Marine Tertiary Beds in the Tejon Hills, Gali. Bi he
Reneauee oy NON ©, Merman s..:0.-:ace0 2. vaste! bene copeertactscescosnetunenedteuedeedutmatae te <The = <.00 eee
1e Martinez Eocene and Associated Formations at Rock Creek on the Western Anes
Border of the Mohave Desert Area, by Roy E. Dickerson .0.......--.csceecessseseseeceesseee 10c
ew Molluscan Species from the Martinez Eocene of Southern California, by Roy ‘+
TI GIs Sta aN BS ck eran rele aN eg iS ee i a AeA er oR cere Soe GEL Oh 5¢
boscidean Tooth from the Truckee Beds of Western Nevada, by John P. wih
(EET A is SIE a8 le nel nb oO ee ER, ee Die ec ee tee Ae De
on the Copper Ores at Ely, Nevada, by Alfred R. Whitman ......02- ee 10e
and Dentition of the Mylodont Sloths of Rancho La Brea, by Chester Stock. 15¢
ttiary Mammal Beds of Stewart and Ione Valleys in West-Central Nevada, by
MMR IMMES TLV LCL). Sane age op eee ese gL ee I lees Ae eS le 3 a a eS ee 30¢c ~—

; chinoids from the San Pablo Group of Middle California, by William S. —
Kew ~ Sacepcd sche gee cere meeeu scp b- DBRDE ucaaiaa a aS eel Poa Rar ee Pee Pee 51 AA Tap ba 10¢

ss, near Pyramid Lake, Nevada, by John C. Merriam ......22.02.----esccsceccscessecesenceeseee ~10e
‘Patna of the San Pablo Group of Middle California, by Bruce L. Clark.............. 1.75

‘wi Index in in press, —
ae * :

. A Stady of the Skull and Dentitior of Bison antiquus Leidy, with Special |

New Species of the Hipparion roup omit the Pacific Coast
inces of North America, by John C. Merriam -.......cscccesee-o
The Occurrence of Oligocene in the Contra Costa Hills of i
Bruce L. Clark ...-2.- a ae ea | RE Ae eC ALUMS ENA Woe iS NEL Lal
The Bpigene Profiles of the Desert, by Andrew C. Lawson ......... oe fs
New Horses from the Miocene and Pliocene of California, by J
Corals from the Cretaceous aud Tertiary of California and Oregon,
MNlomila wed * bop Be ee re a RS ocak cee eee ata
Relations of the Invertebrate to the Vertebrate Faunal Zones of the
Etchegoin oem hii in\the North Coalinga Region, California,
WNomilamd® pentose bc ea ee Pee ee cs DS
A Review of the Apecies Ea californicus, by Loye Holmes Mil
The Owl Remains from Rancho La Brea, by Loye Holmes Millet ......:.
Two Vulturid Raptors from the Pleistocene of Rancho La Brea, by |
GUN fs daa | eon ER eames ey gen OA aN eT
Notes on Capromeryx Material from the Pleistocene of Rancho Ta Brea, ay
Chamdlon ies... |s 004. Bec Re A ee Lae

to Material from the Pacific Coast, by Asa CO. Chandler .......... a ase
Paunal Studies in the Cretaceous of the Santa Ana Mountains of |
fornia, by Marl Leroy Patekard t.2 i245 et -< treet ee eae '

v

0. 13, PP. 161- 198, plate 8, 48 text pues. iesned February 234 1916.

g x
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BY if
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JOHN C. MERRIAM
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VOLUME 6. a

1. The Condor-like Vultures of Raneho Lia Brea, by Loye Holmes Miller... sees 156

2. Tertiary “kammal Beds of Virgin| Valley and Thousand Creek in Northwestern a
Nevada, by John C. Merriam. Part I.—Geologic History.............-.-.ss-ec-scseeeecessaeees a
3. The Geology of the Sargent Oil Fi eld, by. William FL Jones. ....2..-st-cce-cessepene sen eee
4, Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, by

Hoye: Helmres Miller) oon... vce. socn-baceontecsonsnetapae innen=-ulbean anes ce yunPatesncas+ s=aseaheney goaee tena
5, The Geomoij Logeny of the Sierra Nevada Northeast of Lake Tahoe, by John A. Reid
6. Note on a Gigantic Bear from the Pleistocene of Rancho La Brea, by John C.
Merriam.
7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Deg
by John C. Merriam.
Nos...6 and }7 im ONC COVE? <...02.2.20-ccsasncceaeconnsnascterenceserncabencardecenshese=hdeieaeeeaa ee namaEs
8. The Stratigraphic and Faunal Relations of the Martinez Formation to the Giiice
. and Tejon North of Mount Diablo, by Roy E. Dickerson .......-.s-csesecsssssseenessssvesseene
9. Neocolemanite, a Variety of Colemanite, and Howlite from Lang, Los Angeles
County, Cali fornia, by Arthur S. Wake eo. 2. ccc. ic <s cones cke-ae-o--veeunnss eee
10. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor...
11, Tertiary Mammal Beds of Virgin Valley and Thousand Oreek in Northwestern

Nevada, by John C. Merriam. Part Il.—Vertebrate Faunas ...........-scsccseen-s
12. A Series of Bagle-Tarsi from the Pleistocene of Rancho La Brea, by Loye Holmes.
MOUNT ooo alee nt cteeea PS sceeapttasonence sabe dtnadidetiy evesk ales dedtes emt cual tiene a rc

13. Notes on the Relationships of the Marine Saurian ‘Fauna Described from the Triassic -
of Spitzbergen by Wiman, by John C. Merriam. ‘
14. Notes on the Dentition of Omphalosaurus, by John C, Merriam and Harold C, Bryant. _ (a

Nos. 18 and 14 im one) Cover: -2.1. ce. c2.-ecncetncvie--betere--nespcee -eoneneuacre ces eee
15. Notes on the Later Cenozoic History of the Mohave Desert Region in Southeastern ~~
California, by Charles Laurence Baler 22. -200..-.)5-cs0--sesceasu-np-raedee=onces susan 5
16. Avifauna of the Pleistocene Cave Deposits of California, by Loye Holmes Miller ... ls
17. A Fossil Beaver from the Kettleman Hills, California, by Louise Kellogg ........... ee.
18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam .......-.csescsccssoneceen aocraese

19. The Elastic-Rebound Theory of Earthquakes, by Harry Fielding Reid. ....c..ssersscne | a

VOLUME 7.
1. The Minerals of Tonopah, Nevada, by Arthur S. Halkle ..........\..s0s--sssssescnssnvssnnees
2. Pseudostratification in Santa Barbara County, California, by pea Davis ig
back scan
3. Recent Discoveries of Carnivora in the Pleistocene of Rancho La Brea, by Joh ‘
Merriam a. toned cee dennnctwogne bass onbshdcse yits tetas te ecko het ae come es alate
4, The Neocene Section at Kirker Pass on the North Side of Mount Diablo, by |
Te, CUTE oo doen act baa nosso occnan duakaecbeken deteeeeeneacaiett ce feph tEee My AeeRmEe Se pee Sale iad
5. Contributions to Avian Palaeontology from the Pacific Coast of North Ataeriea, 1 4
Loye Holmes, Miller}: 2.2.2... 2. sai ecoeeetes ee PRONE SY aos Saeel
| a

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 13, pp. 161-198, plate 8, 48 text figures. Issued February 23, 1916

TERTIARY VERTEBRATE FAUNA FROM TH*
‘CEDAR MOUNTAIN REGION OF
WESTERN NEVADA

BY
JOHN C. MERRIAM

CONTENTS
DES aa ee G UD WME Ca a ee Pe RE i ee Sn EE
@ COUTT CMCE ieee seo otacce 2 cesee ec cee conde eos secu secuvane stctesenGebsseaecuopeduand notes iubcetsctsacadescctetdeedacsateess
Relation of Cedar Mountain Beds to Esmeralda Formation
Composition of Cedar Mountain Vertebrate Fauna -_.-......222..20..2-0200. es eeeseeeeeeee
Relation of the Fauna to its Environment, ~.......2..22..22..2..22.22sc2sceeeceeceeeeeeeeeeeeeeeeeeeee 168
Stage of Evolution and Relationships of the Fauna ....-...2..22..22..22-..22:22e000e-00-- 169
Weseriptionwot thew Maun ay 2c score sccecksctecensatvecsccatccstececetotescocccaeedeteeuatedee iacedesseitasvesescees 172
)BSTSY CCID 2 re Aa 9 rN ee A ee fee 172
WIRES GUT TAG gg ese ean ees Maas e ceca See TSEEE vase eo Ueetn at v.becst ss eee ees ceces 172
BENS CS ye ee ee as eee eee De deren Ee oases an Pena eaten es Socase beh sega scuniusstseeeemetecszostes 172
(© AETNIGV iG Tek eeers comer eee mee: rts Mae NE et ac SM cet ade 173
Tephrocyon, near kelloggi Merriam .................22..22.::21:02-cecceeeeeeeeeteeeeeeeeeeees 173
(Camm Ave ur OCOD Ss cascte sees se ects cae ceees cemee ser emee ce eaten eee eeeee eee Iz
(CATTLE BES sg cece ree es Sa de S| Re ne ene he 02 eee Fs PRIN ce 174
ON VER ato C6 LA) ec ee oe re ee Pes 175
BEE) 1 Claas Sp sak eee 2 ca rae eae Ue eR eee Sans 175
TNE) 6 Lt) Ogg pee ae ye ae eee eee ee ee 175
IBASSATISCUS | MeVaAGeNSIS, Ws SPs ccevae eres: c-etoleeetecer: veseesscensveceeensevys-s-useevemezsarers 175
ECO OTC LE ge asec eos eo Eats Son ea eae Sats ee Ss cea cocoa ener Dre eee et WETS
Winrordestene ain Tortus (UuetC iy.) zscsersce es eeeeeceessatea_ 022. eese see -suceeeeseseseeeceueere nena 177
IMigva ava WU Site AS [epee seaek es cman aii eae cee eRe cee ng, ree es ce Ae oe ee eee yee 177
PATI LO COTUERANG SSI) saecs cs sacsens eee eo eee eee ape anc eee ee sass ese co tdee sce vecueadetsess etesesu 177
MMe US aM eas avie GUS sell 0 Ot ra ateee. seme cess eaneens soaemee ss aus eese reser oeers sever ce veeneseae 179
TReaNboUOYOCSV COL OKOIEN SY oe eee Me Peano oS eee ee Sea 180
oN} 0) ASH CO) OSH ef Oo ae ce ace tree 181
eX ODOM) OST yet) OF 8. ce ict Ped oe rae Por 7 Pek ee Oe sae ee 181
DCO RU KE =) ee ca ree ee ac Pee eee 181
Hypohippus (Drymohippus) nevadensis Merriam ...............2..2..2022.-2..2..---- 182
Hypohippus, near osborni Gidley -........2...-22...22 222-220 2-cececeeceeeeeeeeeeeeeeeeeees 186

INU ECS CT NAL 9) ON UES TS) Op nye Pa ee ee ene ore ee eee 186

162 University of California Publications in Geology [ Vou. 9

Protohippus?, sp.

PROD OSCLC CS, «ase. 25. cst escce ee anes eens ee
Metrabelod ony, Sys. 2 seks coceecsee sete eceecss se oe ee eee 189
Gammel id ale Peer eaan scree eects cceeaes eee eae ee seat ccateesenene 189
Procamelus, near gracilis Leidy 22.2.2... cccessseceseseseseeevececseseeeeseeeceseeeeseoss 189
Bliawehenia’, Sys cc cscsce.cccecces ccc eee 194
Miery.cod onitid ae pees sree een ne ee

Merycodus fureatus (Leidy)
Merycodus, near neeatus Leidy
Description of Collecting Localities

INTRODUCTION

In a study of the Tertiary faunas of the Great Basin province, now
being carried on by the Department of Palaeontology of the Uni-
versity of California, one of the most fruitful investigations has been
that comprising the exploration of the Cedar Mountain region of
western Nevada. This area was visited by Charles L. Baker and
John P. Buwalda in the summer of 1912 in the hope of finding a
Tertiary mammalian fauna in deposits situated between the occurrences
of Tertiary beds at Virgin Valley and Thousand Creek on the northern
border of Nevada, and those of the Barstow and Ricardo areas of
the Mohave Desert to the south.

Information regarding the occurrence of fossil remains in the area
visited by Baker and Buwalda had previously been received through
the courtesy of Mr. T. Holman Buck of Mina, Nevada, and through
Professor George J. Young of the University of Nevada. Mr. Buck
very kindly visited the localities with Baker and Buwalda, and was
mstrumental in securing and transporting to the railroad some of the
most interesting material, notably the type specimen of a new and
interesting anchitheriine horse. The area was visited by Dr. Buwalda
in July, 1914, for the purpose of reviewing the work carried on in 1912.

The expedition in 1912 secured a significant collection, including
a considerable variety of mammalian forms. Although the amount
of material obtained is relatively small, the faunal representation is
almost as large as that of the Barstow fauna, and in importance the
area ranks with the Virgin Valley and Mohave localities.

In the preparation of the following report on the fauna of the
Cedar Mountain region the writer has been especially indebted to
Charles L. Baker and John P. Buwalda for their energetic prosecu-
tion of the field work through which the collection was obtained,
and to Mr. Buck of Mina, Nevada, for information leading to location

UNIVeCALIES RUBE BUERS DEPT GEOL [MERRIAM] VOL. 9, PL. 8

Outline map of Tertiary provinces in the United States west of the Wasatch
Range. CM, Cedar Mountain beds; EH, Esmeralda beds; T, Truckee beds; MK,
McKnight Miocene; V-T, Virgin Valley and Thousand Creek beds; Rt, Rattle-
snake beds and Maseall; Re, Ricardo beds; B, Barstow beds.

1916] Merriam: Fauna of Cedar Mountain Region 163

of the material and for subsequent assistance in packing and trans-
porting the collection.

The drawings used in illustration of the Cedar Mountain fauna
were all prepared by Mrs. Louise Nash.

OCCURRENCE

As represented on plate 8, the Cedar Mountain region hes a lttle
more than fifty miles east of the western border of Nevada and near
the middle of the state on a north-south line. It is east and southeast
of Walker Lake, and northeast of the town of Mina.

The deposits in which the mammalian fauna occurs are spread
over an area not less than fifteen miles in diameter, in Ione Valley
and in Stewart Valley, but all seem to represent the same formation.

The geology of the Cedar Mountain deposits in which the mam-
malian fauna occurs has been admirably discussed by J. P. Buwalda.'
The Tertiary sediments of the Cedar Mountain region are considered
by Buwalda to represent a portion of the Esmeralda formation
described by Turner? from the Silver Peak region immediately to
the south.

The Tertiary beds representing the Esmeralda formation in the
Cedar Mountain region consist of lacustral accumulations with inter-
ealated beds of terrestrial origin. The formation here has a_thick-
ness of not less than one thousand feet.

The lacustral deposits consist in a large part of sandstones with
shales, cemented tuffs, conglomerates, limestones, and cherts. The
terrestrial beds comprise fanglomerates, sandstones, and pumiceous
tuffs. Within the lacustral beds at several localities are lithoid tufa
domes similar to those occurring in the Pleistocene deposits of Lake
Lahontan.

The Esmeralda formation of the Cedar Mountain region rests in
very marked unconformity upon pre-Tertiary series which were greatly
deformed and eroded before accumulation of the Esmeralda.

Between the Tertiary beds of the Cedar Mountain region and the
older, much disturbed sediments are local rhyolitic and andesitice lavas
markedly unconformable upon the older series, and also apparently
not conformable with the Esmeralda. So far as observed the rhyolite

1Buwalda, J. P., Univ. Calif. Publ. Bull. Geol. vol. 8, pp. 3385-863, pls.
32-38, 1914.

2 Turner, H. W., Amer. Geol. vol. 25, p. 168, 1900. Also U. S. Geol. Surv.

Twenty-first Annual Report, part 2, pp. 192-224, 1900; and Bull. Geol. Soe. Amer.,
vol. 20, p. 243, 1909.

164 University of California Publications in Geology [ VoL. 9

flows antedate the andesites. Basaltie lavas are known to overlie
the Esmeralda beds and seem to rest upon an eroded surface cut in
the Esmeralda.

Judging from the amount of movement and erosion in beds above
the pre-Esmeralda lavas as compared with that between the lavas and
the older series, Buwalda judges that these igneous rocks largely
represent lower or middle Miocene time. A_ post-lacustral andesite
which has been deformed and much eroded is considered as probably
Phocene. A basalt resting in apparent unconformity upon the post-
lacustral andesite at Table Mountain is considered as late Pliocene.

The Esmeralda formation of the Cedar Mountain region has been
subjected to moderate deformation, six or seven low, open folds being
noted by Buwalda in crossing Stewart Valley. Since the time of
principal deformation the beds have suffered extensive erosion, which
has been sueceded by a gentle warping presumed to have taken place
in Pleistocene time.

In a sketch of the historical geology of Esmeralda County, Nevada,
published in 1902, H. W. Turner® refers to lake beds containing
abundant fossils four miles west of Black Spring near the line between
Esmeralda and Nye counties on the road between Sodaville and Clover-
dale. A block containing mollusean and ostracod remains was obtained
by Robert Stewart of Sodaville. This specimen was examined by
J. C. Merriam who recognized the following mollusean forms:

Sphaerium, near idahoense Carinifex, sp. a
Melania?, sp. Carinifex, sp. D

The Sphaerium and two Carinfexr species resembled forms known
from the Truckee beds of Fossil Hill in the Kawsoh Mountains of
Nevada. Two species of Melania are also known from the Fossil Hill
beds. The fauna was considered by Merriam to resemble that of the
Truckee, but evidence of similarity to the Esmeralda was not apparent.

From the block containing the mollusean shells a number of ostra-
cods were obtained. These were referred to Dr. R. H. Chapman. who
identified the forms as follows:

llyocypris, sp. nov., near I. gibba Candona, sp. probably new

but distinet in important points Candona, sp. probably new
Candona, sp. near C. kingsleyi

Organic remains representing plants, molluses, fishes, testudinates.
and mammals were obtained in the Cedar Mountain beds by Baker

3 Turner, H. W., Amer. Geol. vol. 29, p. 268, 1902.

1916] Merriam: Fauna of Cedar Mountain Region 165

and Buwalda. Remains of trees of considerable size were found in
abundance in many localities. About one mile from Stewart Spring
a silicified tree trunk not less than six feet in diameter is exposed.

Buwalda lists the following mollusean forms from the Cedar
Mountain beds:

Heliosoma cordillerana Hannibal Melania, near sculptilis Meek
Viviparus turneri Hannibal Corneoeyelas meeki Hannibal

The Heliosma and Viviparus are both abundant in the type section
of the Esmeralda formation as well as in the Cedar Mountain beds.
The Melania-lke form is near a species described from the Truckee
beds of the Kawsoh Mountain.

Mammalian remains are known from many localities in the Cedar
Mountain sediments of Ione Valley and Stewart Valley. They are
most abundant in the sandstones and tuffs, but a few specimens have
been discovered in angular terrestrial deposits. The material con-
sists commonly of scattered bones, which often give evidence of weather-
ing before burial. Connected parts of the type specimen of Hypo-
hippus (Drymohippus) nevadensis were found in a slab of fine-grained
ashy rock containing a large percentage of lime.

Conditions of occurrence indicate that the mammalian remains
of the Esmeralda beds in the Cedar Mountain region were buried in
part in shore deposits bordering fresh-water lakes, and in part were
entombed in purely terrestrial beds. Remains of the smaller land
mammals, including all of the rodents, are best known in association
with those of fish in shore deposits of a lake. Bones of the larger
land mammals occur to some extent in terrestrial beds.

RELATION OF ESMERALDA FORMATION TO
CEDAR MOUNTAIN BEDS

In his study of the Cedar Mountain region Dr. Buwalda* has
shown that the extensive areas of Tertiary sediments examined in
Stewart Valley and in Ione Valley ean be traced stratigraphically into
the Esmeralda formation described by H. W. Turner in the region of
Silver Peak to the south. In order to assemble all information con-
cerning the time relations of the Cedar Mountain fauna, it is there-
fore desirable to include in this paper a brief statement of the
geologic relations of the Esmeralda formation at the type locality,

4 Buwalda, J. P., Univ. Calif. Publ. Bull. Dept. Geol. vol. 8, no. 19, 1914.

166 University of California Publications in Geology [ Vou. 9

and a summary of available information regarding the fauna and
flora of the Esmeralda.

In the type section of the Esmeralda, Turner describes the for-
mation as consisting of lght-colored marls, shales and sandstones,
water-worn conglomerates, and Tertiary detrital-slope breccias. The
formation was considered to have a thickness of at least 10,000 feet,
and was presumed to represent in large part accumulation in a fresh
or only shghtly saline lake. Remains of plants, fresh-water molluses,
and fish indicated that the beds represented approximately Miocene
age.

An interesting succession of lavas deseribed by Turner from the
Silver Peak region has definite relation to the Esmeralda sedimentary
series and is therefore of unusual importance. The succession is as
follows, reading from the latest members to the earliest ones referred
to the Tertiary :

7. Dark, fine-grained olivine basalt, which may not be later than the Piper

Peak flow.

ci

3. Hypersthene basalt of Piper Peak.
Rhyolite-tuff interbedded with sandstones of the Esmeralda formation.

a |

o

Andesite-breccia.

Rhyolite-tuff.

Andesite-breccia.

Older basalt associated with red basal conglomerate of the Esmeralda
formation.

ep w

The plants of the Esmeralda were examined by F. H. Knowlton?
who listed the following forms:

Gleichenia? obscura Knowlton Quercus argentum Knowlton
Dryopteris? gleichenoides Knowlton Ficus lacustris Knowlton
Spathyema? nevadensis Knowlton Chrysobalanus pollardiana Knowlton
Salix angusta? Al. Br. Cercis? nevadensis Knowlton

Salix vaccinifolia Knowlton Cinchonidium? turneri Knowlton
Salix, sp. Rhus nevadensis Knowlton

Salix?, sp. Indet.

Quereus turneri Knowlton

Dr. Knowlton considered the flora of comparatively recent age
with some species having closely corresponding forms as old as Eocene.

Tree trunks six to eight feet in diameter were found in the Esmer-
alda beds by Turner.

The fish remains were described by Dr. F. A. Lucas® who referred
them to a new species of the cyprinoid genus Leuciscus. This form,

5 Knowlton, F. H., U. 8. Geol. Surv. 21st Ann. Rep. part IT, pp. 209-224, 1900.
6 Lucas, F. A., U. S. Geol. Surv. 21st Ann. Rep. part II, p. 228, 1900.

7

1916] Merriam: Fauna of Cedar Mountain Region 167

Leuciscus turnert Lueas, is not certainly known from localities outside
the Silver Peak region, but pharyngeal teeth of eyprinoid fishes are
found in the Tertiary beds of the Cedar Mountain region. The fish
remains suggested to Dr. Lucas comparatively late age of the Es-
meralda, presumably Phocene rather than Miocene.

Mollusean remains obtained by Turner were examined by J. C.
Merriam’ who did not regard the species as definitely determinative.
One of the species was recognized as near Ancylus undulatus Meek
from the Truckee beds of the Kawsoh Mountains of Nevada. Other
species approached the characters of forms referred to the Kocene.
The Esmeralda was considered as possibly early Miocene or late Eocene.

As nearly as can be determined from available evidence the Esmer-
alda formation, and with it the deposits of the Cedar Mountain
region, should be correlated approximately with the Truckee beds
deseribed by King from the region of the Kawsoh Mountains near
the western border of Nevada some distance to the north. As has
been shown by Buwalda, the mollusean forms of the Cedar Mountain
beds are in part identical with those of the type section of the
Esmeralda. There are also elements of similarity between the mollus-
ean fauna of the Cedar Mountain beds and the small fauna listed
by King from Truckee. Additional evidence of contemporaneity of
the Truckee and Esmeralda is furnished by recent studies of Dr.
F. H. Knowlton on a collection of plants obtained by the University
of California from Truckee beds near Verdi, Nevada. Dr. Knowlton
reports that the strongest affinity of the Verdi flora is with that of
the Esmeralda formation. Of twelve species which Dr. Knowlton lists
from the Verdi flora, six are apparently identical with or closely
related to forms from the Esmeralda flora. The species common to
the Truckee and the Esmeralda are the following:

Salix angusta Al. Braun Cercis? nevadensis? Knowlton, smaller
Salix, sp. Ficus lacustris? Knowlton, much smaller
Rhus? nevadensis Knowlton Chrysobalanus pollardiana Knowlton

Of these the last four species are known only from the Esmeralda
and Truckee beds.

7 Merriam, J. C. See Turner, H. W., U. S. Geol. Surv. 21st Ann. Rep. part
II, p. 203, 1900

168

University of California Publications in Geology

{ VoL. 9

COMPOSITION OF CEDAR MOUNTAIN VERTEBRATE FAUNA

Pisces
Salmon-like form
Cyprinoid form
Testudinata
Possibly Clemmys
Aves
Nettion carolinense (Gmelin)
Marila ecollaris (Donovan)
Querquedula cyanoptera (Vieillot) ?
Carnivora
Tephrocyon, near kelloggi Merriam
Canid, or mustelid, small
Canid, near Aelurodon or Tephrocyon
Felid, large, probably machaerodont
Felid, small, near Lynx
Bassariscus nevadensis, n. sp.
Rodentia
Dipoides, n. sp.
Mylagaulus, sp.
Aplodontia?, n. sp.
Lepus, near vetus Kellogg

Equidae
Hypohippus (Drymohippus) nevaden-
sis Merriam
Hypohippus, near osborni Gidley
Merychippus, sp.
Protohippus?, sp.
Rhinocerotidae
Aphelops?, sp. A
Aphelops?, sp. B
Probosecidea
Tetrabelodon, sp.
Camelidae
Procamelus, near gracilis Leidy
Pliauchenia?, sp.
Merycodontidae
Merycodus fureatus (Leidy)
Merycodus, near necatus Leidy

RELATION OF THE FAUNA TO ITS ENVIRONMENT

A considerable part of the Cedar Mountain fauna comprises types
which might inhabit a region of arid or semi-arid climate not greatly
different from that of the Cedar Mountain area at the present day.
This might be true of the canids, the rabbits, some of the horses, the
camels, the merycodonts, and possibly the felids. Other forms, as
Bassariscus, Aplodontia, and Hypohippus, are types that would natur-
ally frequent a moist region or one well provided with trees or brush.

The remains of fish and of fresh-water shells obtained at certain
localities in the Miocene of the Cedar Mountain region indicate the
Fossil

wood representing trees of large size is common at a number of

presence of fresh-water bodies probably of considerable size.

localities.

From consideration of all biological evidence available it appears
that the environment in the Cedar Mountain region during the deposi-
tion of the mammal-bearing beds must have been noticeably different
from that obtaining there at the present time. The presence of
considerable bodies of fresh-water, the presence of abundant forest

1916] Merriam: Fauna of Cedar Mountain Region 169

trees, the existence of forest forms like Bassariscus and Aplodontia,
and the relative importance of browsing types with rarity of grazing
horses, all suggest a slightly more humid climate, with groves or brush
areas such as may occur around the borders of the Great Valley of
California at the present time.

STAGE OF EVOLUTION AND RELATIONSHIPS OF
THE CEDAR MOUNTAIN FAUNA

Relation of the Cedar Mountain Fauna to the Tertiary Faunas
of the Great Basin.—The faunal assemblage obtained in the Cedar
Mountain region shows affinity with the Middle Miocene of Virgin
Valley, but most nearly approaches the faunal stage of the Barstow
Upper Miocene. It is distinctly older than the Ricardo, Thousand
Creek, and Rattlesnake. Several differences between the Cedar Mount-
ain and Barstow faunas may be due to geographic variation or may
indicate that the Cedar Mountain beds cover a somewhat longer time
range, including both older and younger beds than those from which
collections have been obtained in the Barstow.

The Cedar Mountain fauna resembles that of the Middle Miocene
Virgin Valley in the presence of a Tephrocyon near kelloggi, Hypo-
hippus, Merychippus, rhinoceroses, and a Meryodus near furcatus. It
differs from the Virgin Valley and Maseall in the presence of Dipoides
and Merycodus necatus; in the more advanced stage of the horses; and
so far as known in the quite advanced stage of the Aplodontia-like
rodents, of the camels, and of the merycodont near M. furcatus.

Tephrocyon kelloggi, apparently represented in the Cedar Mountain
by a portion of a lower ecarnassial, was described from the Virgin
Valley. <A similar form is, however, imperfectly known from the
Thousand Creek Phocene. The Hypohippus and Merychippus of Cedar
Mountain are of more advanced types than those of Virgin Valley,
and the Merycodus near furcatus is a larger, heavier form than that
of Virgin Valley.

Dipoides is known in the Cedar Mountain beds but has not been
found in the Middle Miocene. The Aplodontia-like form in the Cedar
Mountain may be a more progressive type than the Aplodontia of
Virgin Valley. Some of the fragmentary horse remains are much
more specialized than any known from the Middle Miocene, and are
even relatively advanced for the Barstow Upper Miocene. The total

170 University of California Publications in Geology [ VoL. 9

assemblage of forms from the Cedar Mountain certainly seems more ad-
vanced than the Middle Miocene of the Great Basin, though it may
approach it more closely than does the Barstow fauna.

Compared with the Upper Miocene fauna of the Barstow beds the
Cedar Mountain fauna is distinguished especially by the absence of
large aelurodons, and by the presence of rhinoceroses with Merycodus
furcatus as the most common merycodont. Other differences, as
the absence of Merycochoerus and Dromomeryx from the Cedar Mount-
ain, and the absence of certain rodents as Dipoides from the Barstow,
may be due to the chances of collecting.

Aside from the differences mentioned above, the Cedar Mountain
and Barstow faunas have in general a similar aspect. The presence
in the Cedar Mountain of a form of Tephrocyon; the occurrence in
both faunas of a very progressive type of Hypohippus, an advanced
Merychippus, and a protohippine form more specialized than typical
Merychippus, indicate that the faunas are not widely separate in
stage of development. It seems evident that the Cedar Mountain is
nearer the Barstow than to any other faunal stage thus far known
in the Great Basin, and is therefore probably of Upper Miocene age.

The presence of rhinoceroses and of Merycodus furcatus in the
Cedar Mountain in the same association as in the Santa Fe Upper
Miocene, whereas they are both absent from the Barstow, may be due
to geographic variation or difference in environment. It is possibly
due to slightly earlier stage of evolution of the Cedar Mountain fauna.
The collections from the Barstow beds are the largest thus far brought
together in the southwestern portion of the Great Basin, but as yet
neither rhinoceroses nor Merycodus furcatus appears in the abundant
material.

Compared with the Ricardo fauna, the mammals of the Cedar
Mountain beds lack the advanced aelurodons, while the horses and
camels are generally much more primitive. The presence of Dipoides,
Mylagaulus, and one rather advanced horse in the Cedar Mountain
beds would seem to show a relatively advanced stage; but Dipoides
and Mylagaulus are both known in the Upper Miocene of America,
although not as yet obtained in the Barstow, while the progressive
horse may not be more specialized than one form in the Barstow beds.

Unless it be true that there is in the Cedar Mountain region a
series of beds somewhat younger than those from which the principal
fauna has been obtained, there is good reason for considering the
fauna of these beds as considerably older than that of the Ricardo.

1916] Merriam: Fauna of Cedar Mountain Region 171

In comparison with the Thousand Creek and Rattlesnake Phocene,
the Cedar Mountain shows a wide difference in the horses and
camels. The presence of Hypohippus and Merychippus with two
species of Merycodus in the Cedar Mountain fauna indieates a much
earlier stage than that of either the Thousand Creek or Rattlesnake,
before the deposition of which these genera had disappeared.

TABLE ILLUSTRATING RELATIVE AGE OF THE CEDAR MOUNTAIN FAUNA COMPARED
WITH OTHER FAUNAS OF THE (?REAT BASIN PROVINCE

Time scale Soe Mohave area
| Upper
|
Pliocene Middle
eee Thousand Creek
ul ‘ ac rc ‘
Rattlesnake Bacardo
Upper ; ; Barstow
Cedar Mountain
Miocene | Middle Maseall
Lower Columbia Lava

Relation of Cedar Mountain Fauna to that of the American Terti-
ary East of the Great Basin.—The age of the Cedar Mountain fauna
is best determined when this assemblage is considered in conjunction
with other lke faunas of the Great Basin region. Considering the
similarity of this fauna to that of the Barstow beds, and the relation
of the latter to the Upper Miocene Santa Fe fauna of northern New
Mexico, there can be little doubt of the relation of the Cedar Mountain
to the Upper Miocene.

Compared directly with the Santa Fe fauna, the Cedar Mountain
mammals in some respects show a closer resemblance than do those
of the Barstow. While the large aelurodons of the Santa Fe are
not as yet known in the Cedar Mountain, there is a noticeable simi-
larity in the camels, in the meryeodonts, and in the presence of
rhinoceroses, the last group being absent from the Barstow.

The Cedar Mountain fauna resembles that of the Upper Miocene
or Lower Phocene Republican River beds of the northwestern Kansas
to a considerable extent, but seems less advanced in the eanids,
which are exclusively large specialized forms at Republican River.
The Snake Creek fauna of western Nebraska also shows an interesting

172 University of California Publications in Geology [ Vou. 9

similarity in the presence of Tephrocyon, a Bassariscus-like form,
Dipoides, Mylagaulus, rhinoceroses, meryeodonts, advanced camels,
Hypohippus of an advanced stage, and Merychippus. The presence
of numerous advanced horses of the Neohipparion, Protohippus, and
Pliohippus types, with the introduction of true antelopes in Neotra-
gocerus, indicates that the Snake Creek is younger than the Cedar
Mountain, but the difference is evidently not measured by the lapse
of more than half of a geological period.

On the whole there seems good reason for considering the Cedar
Mountain fauna as near the Barstow and the Santa Fe in stage, and
somewhat older than the Republican River and Snake Creek.

DESCRIPTION OF THE FAUNA
PISCES

A considerable number of fragmentary fish remains consisting
of isolated vertebrate and parts of head bones were found at several
localities. They include at least two forms, one near the salmon and
the other too imperfect for determination. Professor J. O. Snyder
of Stanford University, who examined the collection of fish remains
from the Cedar Mountain beds writes concerning them as follows:

“‘T am returning the fossil fish remains today and I am unable to say
anything further about them than that they appear to belong to some salmon-
like form and are certainly not members of other families now living in the

Great Basin. There may be more than one species represented. Dr. Jordan
and others here could offer nothing more in way of suggestion.’’

TESTUDINATA

A few fragments of plates found in the deposits at locality 2027
in association with fish remains and with fresh-water gastropods may
represent a tvpe near Clemmys. The material is too imperfect ‘for
satisfactory identification. The form represented by the material
may be a fresh-water type. No remains of land tortoises such as appear
in the Barstow and Ricardo faunas are as yet certainly known from the
Cedar Mountain beds.

AVES

A few fragmentary bird remains obtained in the Cedar Mountain
region by Baker and Buwalda are interesting as representing some
of the very few avian remains known from the West-American middle
Tertiary.

1916] Merriam: Fauna of Cedar Mountain Region 173

Dr. L. H. Miller has kindly examined the material available and
reports upon it as follows:

“*Professor J. C. Merriam of the University of California has recently placed
in my hands a small collection of bird remains collected in the Cedar Mountain

beds of Western Nevada by Messrs. Baker and Buwalda in the summer of
NOH ee
‘““The material was fragmentary and somewhat worn, hence the identity
in some cases is merely approximated. The specimens all represent anserines
which at present inhabit fresh-water bodies or enclosed bodies of brackish
or salt water. These bodies of water may be of most ephemeral nature and
sometimes highly charged with alkaline salts. The presence of the species
in the deposits of Nevada would therefore have little bearing on the question
of climatic conditions during the deposition of these beds.
‘“‘The remains are listed as follows:
Distal end of humerus—WNettion carolinense (Gemlin)
Proximal end of humerus—Near Marila collaris (Donovan)
Distal end of tibia—Marila collaris (Donovan)
Proximal end of ulna—Near Querquedula cyanoptera (Vieillot)
Fragments of fureula—Indeterminate.’’

CARNIVORA

Carnivore remains are imperfectly represented in the collection
from the Cedar Mountain region, but evidently include a considerable
variety of forms. There are probably not less than six or seven species
in the small amount of material available. Of these forms, three are
eanids, two felids, one possibly a mustelid, and one evidently a pro-
eyonid. The Carnivora do not evidence a very close relationship with
those of any other fauna. One of the canids, Tephrocyon near kelloggi,
is almost identical with a species described from the Virgin Valley
Middle Miocene of northern Nevada. Another type is near the stage
of development of the aelurodons of the late Miocene or early Pliocene.

TEPHROCYON, near KELLOGGI Merriam

A portion of a lower carnassial no. 19767 (figs. 2a and 2b) from
Stewart Valiey represents a species near or identical with Tephrocyon
kelloggi of the Virgin Valley Miocene of northern Nevada. The frag-
ment present is almost identical in form with the lower carnassial
of the type specimen. Very slight differences are due mainly to the
difference in stage of wear. The correspondence in form includes
length of heel, size of metaconid, position and form of the small inner
and outer tubercles between trigonid and talonid, the presence of a
faint ridge of the cingulum on the outher side of the heel, and the
development of a faint ridge on the outer portion of the posterior
end of the heel. The measurements are nearly identical.

174 University of California Publications in Geology [ VoL. 9

COMPARATIVE MEASUREMENTS

Type T.

No. 19767 kelloggi
M,, anteroposterior diameter of heel on inner side, ...... 4.3 mm. 4.1
M,, greatest transverse diameter of heel -........20..20022022.....- 6.5 Ue

Fig. 1. Lephrocyon kelloggi Merriam. M, and M, of type specimen,
x 1%. Virgin Valley beds, Virgin Valley, Nevada.

Figs. 2a and 2b. Tephrocyon, near kelloggi Merriam. M,, X 1%. Cedar
Mountain beds, Stewart Valley, Nevada. Fig. 2a, lateral view of M,; fig. 2b,
superior view of heel with protoconid and metaconid of M,.

Fig. 3. Metacarpal III, possibly canid. No. 22289, X %. Cedar Mountain
beds, Stewart Valley, Nevada.

Fig. 4. Aelurodon or Tephrocyon, sp. Portion of mandible with broken
carnassial, no. 19782, X %. Cedar Mountain beds, twenty-eight miles northeast
of Mina, Nevada.

Fig. 5. Mustelid?, indet. Portion of mandible, no. 19781, K %. Cedar
Mountain beds, Stewart Valley, Nevada.

CANID, AELURODON?, sp.

A portion of the mandible, no. 19782, (fig. 4). of a large canid
represents a form near Aelurodon, or Tephrocyon. Of the Great Basin
forms the species seems nearest to an Aelurodon from the Ricardo

fauna.

CANID, sp.

Several astragali (no. 19780) represent a small eanid.

1916] Merriam: Fauna of Cedar Mountain Region

MUSTELID?, sp
A portion of a small mandible no. 19781 (fig. 5) represents a
Canis-like form with slender but thick jaws, small M,, very small
and one-rooted M,, and no M,. It presumably represents an unknown

mustelid in the Cedar Mountain fauna.

FELID, sp. A.
A small phalangeal element
(no. 19800, fig. 9), of a felid
form from Stewart Valley, loeal-

ity 2027, represents a cat of ap-
proximately the dimensions of
the existing wildeat. It is un-
certain whether it represented

the feline or the machaerodine

division of the family.

FELID, sp B.

Phalangeal elements no. 19769
and 19700 (figs. 7 and 8) repre-

sent felids near the size of the
puma. A slender, somewhat cat-
22289 (fig.
3), may not represent a felid
form.

hke metapodial, no.

A humerus, no. 19765 (fig.
6) near the size of that in the

Fig. 6. Felid, indet. sp. B. Portion of
humerus, no. 19765, X %4. Cedar Moun-
tain beds, Stewart Valley, Nevada.

Figs. 7 and 8. Felid, indet. sp. Pha-

langes, nos. 19769 and 19700, kK WM.
Cedar Mountain beds, Ione Valley,
Nevada.

Fig. 9. Felid, indet. sp. A. Phalanx,

no. 19800, XK W%.

Cedar Mountain beds,
: Stewart Valley, Nevada.
Recent puma_ possibly belongs

to one of the felid types mentioned above.

much heavier than in the puma.

The supinator ridge is

MEASUREMENTS OF HuMeERuS No. 19765
Greatest width across distal end 2.200000. . 54,
Least anteroyosterior diameter of trochlea

mm.

BASSARISCUS NEVADENSIS, n. sp.

A portion of the mandible with the carnassial and premolars (fig.
10) from Stewart Valley, Nevada, locality 2027, represents a form
almost indistinguishable from the Recent miners cat of California. The
dimensions of the teeth are almost identical with those of two Recent

176 University of California Publications in Geology [Vor. 9

California specimens. In comparison with the modern Bassariscus
astuta the fossil specimen (no. 19768) shows M, very slightly shorter
anteroposteriorly, and the mandible somewhat higher and thicker. In
the fossil form the posterior border of P, is less distinctly concave
and the posterior cusp is relatively a little less prominent. The
posteroexternal angle of the hypoconid of M, in the fossil specimen is
more distinctly angular than in the Recent specimens of B. astuta
examined.

A satisfactory comparison of the specimen from Stewart Valley with
Probassariscus antiquus from
the Pliocene of Snake Creek,
Nebraska, and the Miocene of
Virgin Valley, is not possible, as
M, is absent. It may be that this
form possessed a paraconid on
the tuberclar molar as in Pyro-

hassariscus, but this cannot be
ee Bae Per ide ied aioe nee determined until more material
x 2. Cedar Mountain beds, Stewart 1S obtained. The mandible seems
Malloy Nevada: noticeably heavier in Probas-
sariscus than in specimen no. 19768, and there is a shght difference in
the proportions of the lower carnassial.

There can be lttle doubt that the Bassariscus form from the
Cedar Mountain region inhabited a territory that was fairly well
watered and partly wooded. The climatie conditions must have been
quite different from those obtaining in the Cedar Mountain region
at the present time.

MEASUREMENTS

P. antiquus
Cedar Mt. B. astuta B. astuta (c) matthewi (d)
specimen(a) Recent (b) Recent Virgin Valley

P,, anteroposterior diameter 4.3 mm. 4.6 4.3
P., transverse diameter ..............-. 2.2 2.3 2.2 aoe
P,, anteroposterior diameter ........ 4.9 De 5) 5.2
P,, transverse diameter .............--. 2.4 2.5 ap 2.4 2.7
M,, anteroposterior diameter ........ (eal 7.3 7.6 6.8
M,, transverse diameter across

DoaSspeKAORONUG| © cece seen ee 3.8 3.9 3.8 3.8
M,, transverse diameter of heel.... 3.2 caja, 3.4 Ball
M,, anteroposterior diameter from

base of protoconid to pos-

Ueda Oe (2000 eee eee ese e 2.4 2.4 2.4 2.8
‘Depth of lower jaw below M,, .... 6.9 6. 6.7 7.8

(a) No. 19768 (b) No. 8800 (c) No. 8799 (d) No. 12539

ap, approximate.

1916] Merriam: Fauna of Cedar Mountain Region ule

RODENTIA
DIPOIDES, near TORTUS (Leidy)
Several specimens from Stewart Valley (locality 2027) represent
a form near this species. (See figs. 11 to 13.)

MEASUREMENTS
No. 19802 D. tortus D. curtus
Length of lower premolar series —......... 17.5 19.5 14.5
P,, greatest anterposterior diameter ...... 6.5 5.9 4.6
P,, greatest transverse diameter ............ 4.8 4.7 3.8
Depth of jaw below M, .............-...--------- 9.5 14. 8.5

He)

Hal

Figs. 11 to 13. Dipoides, near tortus (Leidy). Cedar Mountain beds, Stewart
Valley, Nevada.

Fig. 11. Mandible with P,, no. 19802, X 2; fig. 12, P,, no. 19804, X 2; fig.
13, P*, no. 19803, X 2.

MYLAGAULUS?2, sp.

A fragment of a large molar (no. 19801) from Stewart Valley
(locality 2027) represents a mylagaulid form, but the tooth is too
imperfect for specific determination. The specimen does not appear
to differ distinctly from the fourth premolar of Mylagaulus, and may

be referred provisionally to that genus.

APLODONTIA®?, n. sp.

A single upper premolar, no. 19798 (fig. 14), from Stewart Valley,
(locality 2027) represents a rodent evidently belonging in the group
of the Aplodontidae, but not corresponding exactly to any form known
to the writer. It shows resemblance both to Meniscomys and to
Aplodontia, but does not duphecate the characters of either.

The crown of the tooth is worn down close to the large, very
slightly divergent roots upon which it is supported. On the occlusal
face there are at least four enamel lakes, which extend down almost
to the lower end of the crown.

The form of the crown, taken with the depth and the tendency to
evlindrical form of the enamel lakes, suggests that the normal unworn

erown was short hypsodont.

178 University of California Publications in Geology [ VoL. 9

The character of the tooth resembles in general that of Aplodontia,
but differs in the shortness of the crown or in the depth of the enamel
lakes, as also in the number of enamel lakes. In minor details of
cross-section and in size, specimen 19798 would differ from any A plo-
dontia species known to the writer. In the Recent aplodontias, and
in Aplodontia alexandrae of the Virgin Valley Middle Miocene, the
crown of P* is long hypsodont, and the bottoms of
the enamel valleys at the top of the crown disappear
in early wear. In specimen 19798, the enamel val-
leys reach the lower end of the crown. Either the
tooth was much shorter than in true Aplodontia
or the enamel valleys were deeper.

On specimen 19798, there are four enamel lakes
shown on the occlusal surface. Two are on the
outer half of the surface, and two on the inner half.

Fig. 14. Aplo- In a Recent Aplodontia a fourth upper premolar
dontia?, n.sp. P*,
anterior and ocelu-
sal views, no. 19798, valleys, which apparently correspond to the enamel

x 4. Cedar Moun- : :
tain beds, Stewart lakes seen in slightly worn teeth. A very shallow

Valley, Nevada.

just about to come into use shows two external

valley runs transversely over the tooth from the
mesostyle to the inner border. In Aplodontia alexandrae an unworn
P* shows a form similar in general to that of the Recent species, with
the exception that the valley extending across the tooth from the
mesostyle to the inner border is divided into outer and inner depres-
sions separated by a wall. The outer of these two valleys is apparently
deep, the inner valley is relatively shallow. A somewhat worn speci-
men of Aplodontia alerandrae shows on P* three enamel lakes which
apparently correspond to the anteroexternal, posteroexternal and in-
ternal valleys. Three of the enamel lakes of specimen 19798 correspond
approximately to the three seen in P* of Aplodontia alexandrae.
The anterior and posterior lakes apparently correspond to the large
lakes in Recent Aplodontia. The anterointernal lake seems to cor-
respond to the anterointernal lake of worn teeth of A. alerandrae, or
to the large shallow valley in the unworn specimen. Two very small
canals in specimen 19798 may represent the middle outer valley next
the mesostyle in A. alerandrae, though this must remain doubtful.
The relation of the posterointernal lake of specimen 19798 to the
valleys of A. alerandrae is doubtful. This lake occupies the position
of a posterointernal valley in Meniscomys, which is presumed to be the
ancestor of Aplodontia.

1916] Merriam: Fauna of Cedar Mountain Region 179

The writer considered the possibility that no. 19798 represents
a milk premolar of a form lke the Reeent Aplodontia, and was
fortunate in finding in the California Museum of Vertebrate Zoology
a specimen with Dpm* well preserved. Dpm*‘ of the Recent Aplodontia
resembles specimen 19798 in the reaching down of the enamel valleys
almost to the bottom of the relatively short crown, but the number
of the enamel lakes does not correspond to that in no. 19798, and
the roots of Dpm* of the Recent form are much more divergent than
in the fossil specimen. Divergence of the roots seems to be a necessary
character in the Dpm* in order to permit P* to come down between
the roots.

Though specimen 19798 is evidently nearest to Aplodontia, it shows
an interesting resemblance to Meniscomys. In Meniscomys there are
four valleys which are more pronounced than any other features of
the occlusal surface, and a slight elongation of the crown with deepen-
ing of the valleys might produce in wear a section quite similar to
that in specimen 19798.

The less rounded anterior side of the tooth in no. 19798 is more
as in Meniscomys, as are the short crown and the non-divergent roots.

The exact relationships of this form are uncertain, more than that
it quite certainly belongs with the Aplodontidae. It apparently hes
between Aplodontia and Meniscomys, but is much nearer A plodontia.
Unless the specimen should be found to represent Dpm* of an unknown
species related to Aplodontia alexandrae, it probably pertains to a
genus intermediate between Meniscomys and Aplodontia.

. MEASUREMENTS
Aplodortia Aplodontia
No. 19798 rufa alexandrae
P*, greatest anteroposterior diameter .......... ap 4.2 mm. 5 3.5
P*, greatest transverse diameter .................- 3.9 5 4.
P*, height of portion of crown remaining .... 2.8

ap, approximate.

LEPUS, near VETUS Kellogg
Two teeth from the collection at Stewart Valley, locality 2027,
represent a leporid form which is near Lepus vetus, found in the Virgin
Valley Miocene and Thousand Creek Plocene of Nevada, but is prob-
ably specifically different from that form.
The teeth examined are slightly curved. The convex inner face
shows a deep fold, the borders of which exhibit numerous secondary

180 University of California Publications in Geology [ VoL. 9

plications (fig. 15). The anterior and inner faces are enamel-covered ;
the outer face and a portion of the anterior one are naked. The

Fig. 15. Lepus,
near vetus Kel-
loge. Cheek-
tooth, no 19799,
x 2. Cedar
Mountain beds.
Stewart Valley
Nevada.

enamel of the inner face is covered with a layer of
cement filling the fold on this side. The outer face
is beveled obliquely. The beveled surface is faintly
grooved longitudinally.

MEASUREMENTS OF No. 19799

Weng th oi Crow) 2iceseccseenceeeneeeeeeee eee 9.7 mm.
Anteroposterior diameter ............-...---- 2.
Transverse diameter ............--.--.-+0--00+ 3.7

The form represented by the specimen measured is
considerably smaller than the type of Panolax sanctae-
fidaei from the Upper Miocene of New Mexico, and is
quite certainly specifically distinct.

RHINOCEROTIDAE

Two forms known by astragali representing this group are found

with the Cedar Mountain fauna, but the systematic position within the

group is doubtful in both cases. In addition to these forms a number of

tooth fragments and several foot bones (no, 22284) from near locality
2028 about four miles north of Stewart Spring represent a large
rhinoceros with short feet approaching the 7'eleoceras type.

Fig. 16. Aphelops?, sp. A. Astragalus, no. 19824, X %. Cedar Mountain
beds, Stewart Valley, Nevada.

Fig. 17. Aphelops?, sp. B. Astragalus, no, 19822, X 14. Cedar Mountain
beds, Nevada.

Fig. 20. Hypohippus, near osborni Gidley, M,?, ocelusal view, no. 19763,
natural size. Cedar Mountain beds, Stewart Valley, Nevada.

1916] Merriam: Fauna of Cedar Mountain Region 181

APHELOPS?, sp. A

A large astragalus, no. 19824 (fig. 16), from locality 2026, in
Stewart Valley, represents a rhinoceros with a form of tarsus similar
to that in Aphelops. This astragalus is near the size and form seen in
a specimen from High Rock Canon in northwestern Nevada.

APHELOPS?, sp. B

An astragalus, no. 19822 (fig. 17), with an anteroposterior diameter
about one half that of no. 19824, seems to represent another rhinoceros
possibly near the Aphelops type. This specimen is similar in size and
form to a specimen 1201 from locality 871, presumably from the
Upper John Day Oligocene of the eastern Oregon. The cuboid facet
is a little large and is flatter at the lower end in the Cedar Mountain
specimen. The inner facet for the astragalus is considerably smaller
in the Cedar Mountain specimen.

EQuIDAE

Remains of horses are relatively rare in the Cedar Mountain beds,
and only a very few teeth and isolated limb-bones have been obtained.
Judging by the relative quantity of remains, the horse fauna seems
to have been overshadowed in importance by the camels in this region
during deposition of the Cedar Mountain beds.

The forms known thus far include Hypohippus (Drymohippus)
nevadensis, a species near Hypohippus osborni but possibly identical
with the first-mentioned form, a Merychippus species near the M.
calamarius forms of the Barstow fauna, and a few fragments indicat-
ing the presence of a form more advanced than the common species
of the Barstow. This last form may be comparable to the most
advanced type of the Barstow resembling Protohippus or Pliohippus
and rarely seen in that fauna.

It is perhaps significant that the browsing type, Hypohippus or
Drymohippus, plays a relatively important part in the Cedar Mountain
fauna as it is known at this time. If horses are relatively rare in
Miocene deposits in which ungulates are fairly represented, and if
the Hypohippus type represents a relatively large percentage of the
horses present, one unavoidably considers the possible influence of
environment in determining range and representation of the group.
Absence of grazing horses, as Merychippus, and presence of browsing
forms would be due to absence of grass or to predominance of brush.

182 University of California Publications in Geology | VoL. 9

The physical conditions under which the Cedar Mountain beds were
deposited do not suggest a predominantly forested or brushy region,
though both trees and brush were presumably present. It may be
that grazing was relatively better elsewhere, and that Merychippus
was abundant in regions not far distant.

HYPOHIPPUS (DRYMOHIPPUS) NEVADENSIS Merriam
Hypohippus (Drymohippus)nevadensis Merriam, Univ. Calif. Publ. Bull.
Dept. Geol. vol. 7, p. 420, 1913.

Type specimen no. 21056, University of California Collections in Vertebrate
Palaeontology. From the Cedar Mountain beds, in Stewart Valley, twenty-four
miles northeast of Mina, Nevada.

Characters much as in Hypohippus, but metaloph of milk molars not con-
nected with ectoloph.

Type specimen a small portion of the skull with three milk molars, portions
of all four limbs, and a number of scattered fragments of other skeletal parts.

Skull and Dentition—All that remains of the skull consists of a
portion of the lower region of the cranium. The part of the cranium
present exhibits little of significance.

The dentition of the type skull shows three well-preserved cheek-
teeth. The incisors are not present. The cheek-teeth represent the
milk dentition with Dm* just coming into function. The teeth rep-

i We ? | Hi

Fig. 18. Hypohippus (Drymohippus) nevadensis Merriam. Upper milk
molars, outer and occlusal views, no. 21056, natural size. Cedar Mountain beds,
Nevada.

1916] Merriam: Fauna of Cedar Mountain Region 183

resent an animal larger than any of the known forms of Hypohippus,
but approaching in size Hypohippus affins, the largest deseribed
species. They are absolutely larger than the permanent premolars of
HT. osbormi, and larger than the milk molars of the type specimen of
H. affinis. The excess in dimensions is evident in both the antero-
posterior and transverse diameters.

In form and pattern the milk molars resemble in general the per-
manent dentition of Hypohippus osborm.

The principal difference between the Nevada specimen, no. 21056,
and Hypohippus osborni is found in the separation of the outer end
of the metaloph from the eetoloph. In none of the milk molars of
the Nevada specimen is the summit of the outer end of the metaloph
connected with the ectoloph. In Dm? and Dm® the base of the met-
aloph searcely reaches the base of the eectoloph. In each of these
teeth there is a small transverse ridge or tubercle pointing inward
from the ectoloph at the posterior end of the paracone crescent. This
transverse prominence arising from the ectoloph extends inward near
the outer end of the metaloph but fails to meet that ridge. The outer
end of the metaloph tends to swing a little in front of the inner
transverse prominence of the ectoloph.

The inner transverse prominences arising from the ectoloph attain
their greatest elongation or height near the summit of the ectoloph,
and rapidly diminish in height as they extend toward the base of the
tooth. On Dm‘ the transverse prominence consists of two small tooth-
like projections. On the longer or lower of these points the diameter,
parallel with height of the tooth crown, is not more than twice the
anteroposterior diameter. The second projection, situated farther
toward the base of the ectoloph, is an exceedingly small tubercle.
The smaller projection does not reach the bottom of the valley between
the metaloph and the metacone crescent. On Dm* the inner transverse
prominence of the ectoloph is very small, and is situated near the
erest of the ectoloph. On Dm? the prominence is higher, but is
reduced rapidly at the proximal end and does not connect with the
metaloph.

The Nevada form seen in specimen 21056 represents a type with
dentition in general close to that of Hypohippus, but distinguished
especially by the less advanced stage of evolution of the metaloph
in the temporary molars.

Limbs.—Portions of both the anterior and posterior limbs (fig. 19a
and 19b) exhibit some of the essential characters. The general

184 University of California Publications in Geology [ VoL. 9

structure and proportions of the parts of the extremities preserved
are near those of Hypohippus. The lateral digits and their ungual
phalanges are relatively large, and were evidently functional. The
first and second phalanges of the median digit are relatively shorter

Figs. 19a and 19b. Hypohippus (Drymohippus) nevadensis Merriam, no.
21056 K YS. Cedar Mountain beds, Nevada.
Figs. 19a, anterior limb; 19b, posterior limb.

and wider than in the Merychippus forms of the Miocene. The ungual
phalanx of the median digit is broad, and the lateral wings show a
stage of development at least as advanced as in Hypohippus. Meta-
carpal three shows a distinctly oblique lateral facet for articulation

1916]

Merriam: Fauna of Cedar Mountain Region

185

with the unciform. In metatarsal three there seems to be a very small
and quite oblique facet for the cuboid.

resembles that of Hypohippus.

In general the limb structure

COMPARATIVE MEASUREMENTS OF DENTITION

Milk dentition

Permanent dentition

H. nevad- H. affinis
ensis Type jals i
No. 21056 specimen osborni equinus

Dm’, anteroposterior diameter along

outer border ..........--..--.--0.---.-00--0- So MMM a eeeeae P? 27.3 25
Dm’, greatest transverse diameter 29 2 2 2 ou... Pa =26 25
Dm’, anteroposterior diameter along

outer border ._-.--.......-2.-----c--ceec-es S168:) Wes P? 25.4 25
Dm’, anteroposterior diameter meas-

ured through protoconule and

hypostyle ...........2.22.22220220220-1--+ 20 see P? 24 22 b
Dm‘, greatest transverse diameter 30.5 — ........ P* 30 27
Dm‘, anteroposterior diameter along

outer border .............2.--2------------ 31.9 ap 28.5 ap P* 30 25
Dm‘, anteroposterior diameter meas-

ured through protoconule and

INV POSLY Ces seeer renee essen sremer eevee eres 26.7 a P* 25 22 b
Dm‘, greatest transverse diameter 31.4 29 ee 3.) 26

a, measurements from J. Leidy’s figure of type specimen.

b, from W. B. Seott’s figures of type specimen.

ap, approximate.

MEASUREMENTS OF LIMB ELEMENTS, No. 21056

Radius, greatest length of shaft 241 mm.
Radius; least wadth ot (shat) cesses seeec ce ceceeseccnceceen teens s-sesess 25
Mietacanpalibsonea testi lem piiliecs-:scstete access cacereesc en ceecercsceesceecaaszer sures 190
Metacarpal III, greatest length .......02..22..22..222eceeeeeeeeeeee eee eee 192
Metacarpal III, width of distal end, approximate —................. 28.5
Phalanx I, digit III of anterior extremity, greatest length -.... 40
Phalanx IJ, digit III of anterior extremity, greatest width ...... 30
Phalanx II, digit III of anterior extremity, greatest length...... 30
Phalanx II, digit III of anterior extremity, greatest width........ 31
Mietatansall IM, preatest leno th: 2222.s22o22ccociececcs.ceccccesecece eo ssncsecssessee 2038
Metatarsal IV, greatest width at proximal end ..............2...2........ 17
Phalanx I, lateral digit (hind foot?) greatest length along

SUPCTUOM (SIUC s2steeccssecsceesece: <aacnteee ceceene atch stecaseeecsesecsstespecndscaceeS-so-teie 23.5

Phalanx ITI, lateral digit (hind foot?) length along superior

side

Relationships.—The form represented in specimen no.
bles Hypohippus in the characters of the limbs and in

of the cheek-teeth.

metaloph and ectoloph in the milk dentition.

w
oO

21056, resem-
general form

It differs from Hypohippus in the separation of

It is uncertain whether

the permanent dentition of this species is represented in any of the

186 University of California Publications in Geology [ Vor. 9

collections from the Great Basin region. The total characters. so far
as known, indicate that the species is much nearer to Hypohippus than
to any other group, and excepting the separation of metaloph and
ectoloph it is not clearly distinguished from that genus. The gap
between this form and typical Hypohippus seems less than the spaces
between other anchitheriine genera. The new subgenus, Drymohippus,
proposed to include this form, bears the characters of Hypohippus
excepting in the separation of metaloph and ectoloph in the milk
dentition. Later investigations may add other distinctive characters.

HY POHIPPUS, near OSBORNI Gidley

A lower molar (no. 19763, fig. 20) from locality 2027 represents
a species of Hypohippus near the form found in the Middle Miocene
of Virgin Valley in northern Nevada. This species is apparently
nearer to Hypohippus osborni than to H. equinus or to H. affinis.
Specimen no. 19763 is almost identical in dimensions with the Virgin
Valley form. The tooth resembles the Virgin Valley species in form
excepting in the character of the entostylid, which is relatively very
weak in no. 19763. It is not improbable that additional material may
show that the Nevada species is distinct from those previously des-

eribed from other regions.

COMPARATIVE MEASUREMENTS

No. 12587 Hypo-

Virgin hippus
No. 19763 Valley osborni H. equinus’ H.affinis
M,, anteroposterior diameter — ........ 22. mm, 23.8 23. 28.5
M,, transverse diameter ...... 0 -...... 16. 18.1 14, 20.
M., anteroposterior diameter... 20.7? 21. 23.5 22), 1) ages
M., transverse diameter —_...... 14.3? 14.4 16.2 TDs gee

Two fragments of upper molars evidently represent Hypohippus.

MERYCHIPPUS, sp.

The proximal phalanges of the protohippine horse (figs. 26 and 27)
from locality 2027 represent a type almost exactly similar to proximal
phalanges of Merychippus from the Middle Miocene of Virgin Valley.
They are also very close in form to phalanges of Merychippus from
the Barstow Miocene. The Cedar Mountain specimens show a little
less median constriction than the average specimens from the Barstow
fauna, and in this respect are more like the Virgin Valley form.

1916] Merriam: Fauna of Cedar Mountain Region 187

Figs. 21 and 22. Merychippus, sp. Fig. 21, M;, external and occlusal views,
no. 19825, natural size; fig. 22, incisor, inner and occlusal views, no. 22287,

natural size. Cedar Mountain beds, Nevada.

Figs. 23 and 24. Protohippus?, sp. Fig. 28, inner portion of lower molar,
no. 214838, natural size; fig. 24, outer portion of upper cheek-tooth, no. 22286,
natural size. Cedar Mountain beds. Nevada.

Fig. 25. Merychippus? or Hipparion?, Ineisor, external and occlusal views,
no. 22285, natural size. Cedar Mountain beds, Ione Valley, Nevada.

Figs. 26 and 27. Merychippus, sp. Proximal phalangeal elements, XK W.
Fig. 26, no. 19828; fig. 27, no. 22291. Cedar Mountain beds, Stewart Valley,
Nevada.

Figs. 28a and 28b. Merychippus?, sp. Proximal end of metatarsal III, no.
21482, & %. Cedar Mountain beds, Stewart Valley, Nevada.

188 University of California Publications in Geology [ Vor. 9

A caleaneum (no. 21481) from locality 2027 represents a Mery-
chippus-like species probably identical with that shown in the proximal
phalanges.

The proximal end of a slender metatarsal (figs. 28a and 28)
no. 21482) shows well-developed cuboid and mesocuneiform facets.
It differs from Merychippus, and from the larger forms of the Ricardo
referred to Hipparion and Pliohippus. The mesocuneiform facet is
large, but is somewhat smaller than the cuboid facet. Both euboid
and mesocuneiform facets are nearly flat, or in the plane of the ecto-
cuneiform facet. This specimen may represent Hypohippus. It differs
from that genus in that the cuboid facet is nearly in the plane of the
ectocuneiform facet, while in Hypohippus, as known to the writer, the
cuboid facet slopes at an angle of near 45° from the plane of the
ectocuneiform facet. In Pliohippus there is a distinct mesocuneiform
facet, but the euboid articulation is relatively larger.

A lower molar (no. 19825, fig. 21) from locality 2029 represents
a protohippine horse of approximately the stage of evolution seen in
one form of Merychippus near calamarius of the Barstow fauna. The
crown is of moderate leneth and well cemented. The metaconid-
metastylid column is short anteroposteriorly.

A fragment of an incisor (no. 22287, fig. 22) shows well-marked
cupping and abundant cement in the pit. The stage of evolution of
this tooth is approximately that of M. calamarius.

PROTOHIPPUS?, sp.

Several fragments of upper cheek-teeth from localities 1979, 1984,
2029, and 2025 represent protohippine forms (fig. 24) at least at
large as a very large Merychippus or Protohippus species of the
Barstow fauna. These specimens may represent an advanced Mery-
chippus, a Protohippus, or possibly a Hipparion. A rather narrow
fossette of an upper cheek-tooth shows considerable crinkling of the
enamel. It may represent a Merychippus or a Hipparion,

A large incisor (fig. 25) with deep cement-filled pit is larger
than the incisors of any protohippine form known from the Barstow
fauna. It corresponds more nearly to the stage of advance of a large
Hipparion form of the Ricardo fauna.

A fragment of a lower cheek-tooth (no. 21483, fig. 23) exceeds
the dimensions of the average of the largest protohippine form of
the Barstow fauna. The metaconid-metastylid column is short antero-
posteriorly, and of the Pliohippus rather than of the Hipparion type.

1916] Merriam: Fauna of Cedar Mountain Region 189
4

The horses of the Cedar Mountain region possibly represent two
horizons; one near that of the Barstow beds; the other possibly later
and nearer the Ricardo stage, or possibly intermediate between Barstow
and Ricardo.

PROBOSCIDEA
TETRABELODON, sp.

Remains representing a large mastodon-like form are known from
locality 1988. Several fragments of the lower jaw show a dentition
including at least three cheek-teeth
simultaneously in place in the man-
dible. Two large lower tusks are in
place in the anteroposteriorly elon-
gated symphysial portion of the jaw
(figs. 29a and 296). A partial enamel]
covering is shown on the lower tusks.
No specimens have been found in
which the occlusal portion of the
cheek-teeth is satisfactorily shown.

CAMELIDAE
PROCAMELUS, near GRACILIS Leidy

A specimen, no. 19820 (figs. 30a to
33) representing a small camel found
by Baker and Buwalda, at locality
2028 in Stewart Valley, consists of a
mandible with dentition, the anterior
end of the cranium, a nearly complete

anterior limb, six vertebrae and sev- ey,

eral other scattered fragments of the Figs. 29a and 29b. Tetrabelo-
don, sp. Symphysial region of
mandible, inferior view and eross-
This species is near Procamelus section, no, 22292, x 14. Fig. 29a,
= . . . inferior view; fig. 29b, cross-sec-
gracilis and P. occidentalis, but is — tion of distal end showing inferior
1neisors.

skeleton.

nearer the former in absolute size and
in proportions of premolars. The dimensions of the Nevada form are
close to those of Leidy’s type and are near those of the specimen from
New Mexico originally described by Cope as P. occidentalis,® but later
referred by him to P. gracilis.° Cope’s specimen is slightly smaller

8 Cope, E. D., U. S. Geol. Surv. west of 100th meridian, vol. 4, p. 329, 1877.
9 Cope, E. D., Geol. Surv. Texas, 3rd Ann. Rep. for 1891; footnote on p. 37.

190 University of California Publications in Geology [ VoL. 9

and the metapodials seem a little more slender, but as nearly as can
be determined by comparison of the upper jaw in Cope’s specimen with
the lower jaw from Nevada, the reduction of the premolars is nearly
the same.

The reduction of the inferior premolars compared with the size
of the molars, and especially with that of M,, is greater than in any
of the other Procamelus forms known to the writer.

The Nevada form differs from P. robustus Leidy and P. madison-
danus Douglass through its smaller size; from P. lacustris Douglass
through its smaller premolars; from P.? elrodi through its shorter
molar-premolar series, and smaller premolars; from P. fissidens Cope
through its relatively reduced premolars.

In the cranial fragment represented in specimen no. 19820 (figs.
3la to 31c), the rostrum is somewhat higher and in superior view
apparently wider than in the skull of P. gracilis figured by Cope.’®
The Nevada specimen has been crushed shehtly and this may account
to some extent for its apparently greater relative width. The narrow
nasals are in broad contact with the premaxillaries anteriorly. In
the Nevada specimen, the palatal surface between the anterior pre-
molars is much narrower relatively than in the specimen described
by Cope.

The mandible (figs. 30a and 30b) does not appear to differ in
proportions from that of P. occidentalis and P. robustus.

In the inferior dentition every element is represented. The wide
crown of IL, is separated from the canine by a diastema less than one
third the length of the diastema between the canine and P,. P, has
a simple blade-lke crown. The root is grooved laterally and may be
completely divided at the lower end. P, has a blade-like crown with
faint incipient folds of the enamel at the anterior and posterior ends
of the inner side. The worn crowns of the fourth premolars show
a posteroexternal and an anterointernal fold. The crowns are probably
in too advanced a stage of wear to show the posterior fold. M, is
much worn and shows no distinctive characters. In M, the posterior
lobe is relatively wide transversely. M, is uncommonly long antero-
posteriorly. Compared with other forms its anteroposterior diameter
is very large in relation to the dimensions of the premolars. The
posterior lobe of M, stands almost parallel with the plane of the first
and second lobes, showing a searcely preceptible bend outward. The
medial wall of the posterior lobe is nearly even with the plane of

10 Op. cit., pls. 76 and 77.

191

Fauna of Cedar Mountain Region

Merriam:

1916]

Figs. 30a to 31ce. Procamelus, wear gracilis Leidy. Mandible with a portion of the rostral region, no. 19820, X 144. Cedar

Mountain beds, Stewart Valley, Nevada.

Fig. 30a, mandible, lateral view; fig. 30b, mandible superior view; fig. 3la, rostral

region, lateral view, showing premaxillary with a portion of the nasals and maxillary: fig. 31b, rostral region, superior view;
fo} ’ ’ fo} ne Pp , fo} to} ,

fig. 31lc, rostral region, palatal view.

192 University of California Publications in Geology [ Vou. 9

the middle lobe, but is separated from it by a small, sharply-marked
fold or jog of the inner wall.

Excepting I,, the canine, and P, the upper dentition is known only
by fragments.

An anterior limb (figs. 32 and 383) lacking only the terminal
phalanges and the proximal end of the humerus closely approaches the

Figs. 32 to 34. Procamelus, near gracilis Leidy. Cedar Mountain beds, Nevada.
Fig. 32. Epipodial segment, anterior limb, no. 19820, XK 1%.

Fig. 33. Metapodials and phalanges, anterior limb, no. 19820, X %.
Fig. 84. Cannon bone, posterior limb, no. 22298, X ¥4.

1916] Merriam: Fauna of Cedar Mountain Region 193

characters shown in the limb of the specimen of Procamelus gracilis
described by Cope from New Mexico. The metapodials of the Nevada
specimen are about one tenth larger than in the New Mexico form,
and also slightly heavier. The two elements of the cannon bone are
completely fused, though the distal separation reaches considerably
higher on the shaft than in the llama.

The epipodial segment of the lhmb does not differ noticeably from
that of the New Mexico specimen. The ulna and radius are completely
fused.

re| A
s a Ais 5
3 S ° = q n 8
MEASUREMENTS BS Ch uae ce eee
ioe) Setar ga ao
$2 eee 80 es
ee mes CR FB
oo one a oace
Az ao ME
Length, anterior side I* to posterior side P" ...... 54. mm. 44 ww ee
Length, posterior side superior canine to an-

CEVIOT: SIMe GPP eee eee encanta rece eeeneesee oe 20.5 Gs geseetz sedeses
Width between inner sides of. third upper

MTU GUS OS Ogee teers casestaey sve cccse 2c sesetec eee eens szecd 22.7 QOG) aistde es
Width between inner sides of first upper pre-

TINO VATS fees so eeve cease sateoetense~ csc veacee-nveresise eeseewsevesstte 12.4 WG | asic. $n ses
Length, anterior side inferior canine to pos-

POTUONA SVC ce teeens eee eee secs 1187.8 eC eee e
Length, anterior side P. to posterior side Py 29,0 _WWW. 42.2 48
Length, anterior side P, to posterior side M,; 11, 22 ee ee ee
Length, anterior side M, to posterior side M, 81.2 2 wu ee ee
Height of mandible below anterior side of M,; 50.7 2 eee 60
Height of mandible below anterior side of M, 47.5 2 wu Le. 52.5
Anteroposterior diameter of symphysis ............ 6.0 Sse
Inferior canine, greatest anteroposterior diameter 8.2
P,, greatest anteroposterior diameter ................ eisy NS ee ee
P., greatest anteroposterior diameter ................ oh 3 15
P;, greatest anteroposterior diameter ................ 11.9 14.7) 17.3
P,, greatest anteroposterior diameter ...............- 14.8 16.4 20.38
M,, greatest anteroposterior diameter -............... WG eee 22 29.8
M., greatest anteroposterior diameter ................ en ee 28.5 33?
M., greatest transverse diameter of posterior 28 Ee

Ob owe eae re. ceed ees ne 16.2 iO ig peers eee
M,, greatest anteroposterior diameter ................ 40. Bese oT 48

OA
Anterior cannon bone, greatest length ............ 245, DOD eee cssces eee
Anterior cannon bone, greatest proximal width 43. SOT ou eee ares
Anterior cannon bone, greatest distal width... 51.5 ADGie goeis © ats
Anterior cannon bone, least transverse diameter

OmM Sa Oks betes cesese cases etetac was dear eesce eeemei ota 7 STR 23.5 DOR ee Sse
Phalanx one, anterior extremity, greatest length 75. Dee eae

194 University of California Publications in Geology [ Vou. 9

A well-preserved atlas and a portion of an axis with specimen
19820 do not differ appreciably from those of Cope’s New Mexico
specimen excepting in their slightly larger size.

PLIAUCHENTA?, sp.

Astragal and phalanges (figs. 35, 37 and 40) of a large camel
having at least twice the bulk of Procamelus gracilis are found in the
Cedar Mountain fauna. These elements correspond approximately to
foot-bones referred to the genus Pliauchenia in the fauna of the
sarstow beds. Until material showing structure of dentition and limbs
is adequately represented, it is useless to speculate as to the specific
determination of the form represented by these specimens.

MERYCODONTIDAE

A small collection of the material including antlers, teeth, and a
portion of a jaw from the Cedar Mountain region represents one or
more species of Merycodus. One form seems identical with M. furcatus,
another is indistinguishable from antlers which form a part of the
series included in M. necatus from the Barstow beds.

MERYCODUS FURCATUS (Leidy)

A nearly complete antler no. 21492 (fig. 44) from Tone Valley
resembles Merycodus furcatus in the round, little-flattened beam with
strongly-curved, slender tines.

A second specimen, no. 19807 (fig. 45) shows a long, slender beam
with nearly circular cross-section. It is broken above and shows no
tines. This form of antler is entirely unlike that of Merycodus
necatus, but may appear in M. furcatus. The majority of the frag-
ments of antlers found seem most nearly to approach the M. furcatus
type.

A portion of a jaw, no. 19805 (fig. 46) found at the same locality
with the slender antler no. 19807 shows the last two inferior premolars.
A number of scattered teeth include M, and M,. The lower molars
are strongly hypsodont. M, (fig. 48) shows a moderately developed
third or posterior lobe. The premolars in no. 19805 are somewhat
elongated, while the inner lateral grooves are short and deep. The
outer posterior lateral groove is imperfectly marked, and in this respect
these teeth seem less progressive than in the premolars from the

1916] Merriam: Fauna of Cedar Mountain Region 195

Barstow fauna referred to MW. necatus. According to Cope’s figures,"'
M. furcatus seems to be distinguished from M. necatus by narrower
inferior premolars with less marked posteroexternal groove. These

|
Dh I)

———a<litin,

Figs. 35-41 represent specimens from the Cedar Mountain beds in Nevada.

Fig. 35. Pliauchenia?, sp. Astragalus, no. 22294, K 14.

Fig. 36. Procamelus, sp. Astragalus, no. 22295, K %.

Fig. 37. Pliauchenia?, sp. Proximal phalangeal element, no. 22302, superior
view, X 4.

Figs. 38 and 39. Procamelus, two species? Proximal phalangeal elements,
superior view. Fig. 38, no. 22296, XK 14; fig. 39, no. 22297, X 4.

Fig. 40. Pliauchenia?, sp. Second phalangeal element, superior view, no.
22298, X \.

Fig. 41. Procamelus, second phalangeal element, no, 22299, XK 14.

teeth are in some respects like those of Blastomeryx, but the crowns
are more hypsodont. From the character of this specimen and its
association with molars and antlers of Merycodus, it is probably to
be referred to that genus.

11 Cope, E. D., U. 8. Geol. Surv. West of 100th meridian, pl. 82, figs. la to 2b,
1877.

196 University of California Publications in Geology [ Vou. 9

47

Fig 42. Merycodus, near necatus Leidy. Antler, no. 21498, X %. Cedar
Mountain beds, Ione Valley, Nevada.

Figs. 43 to 45. Merycodus furcatus (Leidy). Antlers, X 1%. Cedar Mount-

ain beds, Nevada. Fig. 48, no. 19806, Ione Valley; fig. 44, no. 21492, Ione
Valley; fig. 45, no. 19807, Stewart Valley.

Figs. 46 to 48. Merycodus, sp. Cedar Mountain beds, Stewart Valley,
Nevada. Fig. 46, lower jaw with P, to P,, no. 19805, x 114; fig. 47, M,,
no. 22300, natural size, external and occlusal views; fig. 48, M;, no. 22301,
external and occlusal views, natural size.

1916] Merriam: Fauna of Cedar Mountain Region 197

MERYCODUS, near NECATUS Leidy

A single antler no. 21493 (fig. 42) from Ione Valley shows a form
not distinguishable from one phase of the series of antlers referred
to Merycodus necatus in the Barstow fauna. The form of the antler
is not greatly different from that in no. 21492 (fig. 44) referred to
M. furcatus, but the beam is more strongly flattened and broadens
more gradually above. The tines seem to have been relatively smaller,
shorter, and less curved than in the other form. This specimen may
represent only a form of the M. furcatus series, but must be recognized
tentatively as like the form from the Barstow beds referred to M.
necatus.

A ealeaneum from locality 2022 in Ione Valley represents a Mery-
codus species.

DESCRIPTION OF COLLECTING LOCALITIES IN THE CEDAR
MOUNTAIN REGION OF WESTERN NEVADA

Loe. 1969. South side of gulch in low blutfs just west of outcrop of plutonic
rock, on south side of road 4% mile east of point at which 5,800-foot contour
crosses the direct road from Bell Spring to Black Spring. Basal beds. Tonopah
Quadrangle.

Loe. 1970. Fifty feet stratigraphically above very fossiliferous shell beds
on north side of shallow canyon, % mile north of the direct road from Bell
Spring to Black Spring. Elevation 6050 feet. Tonopah Quadrangle.

Loe. 1971. At 6250 feet elevation, 1 mile north of road intersection which
intersection is 2 miles southeast of Bell Spring. Probably near base of lake
beds series. Tonopah Quadrangle.

Loe. 1972. At 6075 feet elevation, 14% mile northwest of point at which
6000-foot contour crosses the road between Bell Spring and Black Spring.
Tonopah Quadrangle.

Loe. 1973. In first gulch north of direet road from Bell Spring to Black
Spring. Between 5900 and 6000-foot contours, on a small hill in the middle of
the gulch. Horizon not near base. Tonopah Quadrangle.

Loe. 1974. One-fourth mile northeast of loc. 1973. Tonopah Quadrangle.

Loe. 1975. At 5775-foot elevation, 1% mile north of direct road from Bell
Spring to Black Spring. Tonopah Quadrangle.

Loe. 1976. In a fine, light brown tuff 30 or 40 feet above the granite con-
tact, at a point on the 6000-foot contour, about 1144 miles north of the direct
road from Bell Spring to Black Spring. Tonopah Quadrangle.

Loe. 1977. On the 6300-foot contour, about 4 mile south of conspicuous,
lava covered butte, which is 1% miles east of Bell Spring. Tonopah Quad-
rangle,

Loe. 1978. On the southern-most flanks of the Shoshone Mountains, about
% mile north of the road between Black Spring and Cloverdale and about 300
yards east of the road to Willow Springs near 5500-foot contour. Tonopah
Quadrangle.

198 University of California Publications in Geology [VoL. 9

Loe. 1980. About 14 mile north of loc. 1969, in a small side canyon 50 yards
east of low cliffs in the first large canyon north of the direct road from Black
Spring to Bell Spring. Tonopah Quadrangle.

Loe. 1982. Near the bottom of gulch 4% mile north of highest butte of
the Esmeralda beds in the middle of Stewart Valley, % mile west of Finger
Rock Wash, and about 2 miles west of Stewart Spring. Soft rusty-brown beds.
Tonopah Quadrangle.

Loe. 1984. In Finger Rock Wash at elevation of 5550 feet. Tonopah
Quadrangle.

Loe. 1985. About 1% mile due west of loc. 1986, in the strata immediately
above the gray tufaceous layer prominently exposed along the west side of the
gulch. Tonopah Quadrangle.

Loc. 1986. Immediately south of the point at which the mapped road from
Stewart Spring to Pactolus crosses the line between Nye County and Esmeralda
County. Tonopah Quadrangle.

Loe. 1987. One-half mile southwest of the point at which 6000-foot contour
crosses the line between Nye County and Esmeralda County, about 3 miles
north of the Nevada Mine. Tonopah Quadrangle.

Loc. 1988. A point immediately west of the intersection of the 6000-foot
contour and the line between Nye County and Esmeralda County, about 3
miles north of the Nevada Mine. Tonopah Quadrangle.

Loe. 1989. Three miles east of Table Mountain, immediately northwest of
small hill west of road leading north to Stewart Spring, longitude 117° 55’
west, latitude 38° 32’ north. Tonopah Quadrangle.

Loe. 2021. On 5900-foot contour 234 miles due west of B. M. 5571, which
B. M. is near Black Spring. Tonopah Quadrangle.

Loe. 2022. One-fourth mile southeast of loc. 2021. Tonopah Quadrangle.

Loc. 2023. One-half mile west of loc. 2021 and in the same gulch on the
6000-foot contour. Tonopah Quadrangle.

Loe. 2024. About 4% mile due west of loc. 2021 on the south side of the
same gulch. Tonopah Quadrangle.

Loe. 2025. About 34 mile south of loc. 2021, near the 6000-foot contour.
Tonopah Quadrangle.

Loc. 2026. About 2 miles south, 76° west, from the higher of two buttes
situated in Stewart Valley, about 1%4 to % of a mile west of the point where
Stewart Spring Gulch joins Finger Rock Wash. About 200 feet above the base
of the series. Tonopah Quadrangle.

Loe. 2027. Gray beds in the forks of the mapped roads at Stewart Spring.
Tonopah Quadrangle.

Loe. 2028. Along the road one mile west of loe. 1986. Tonopah Quadrangle.

Loe. 2029. One-half mile northeast of loc. 1986 in gulch cut into brown tuff.
Tonopah Quadrangle.

Loe. 2030. About 2 miles west of the Nevada Mine and immediately south
of the East West road at this point. Tonopah Quadrangle.

Loc. 2031. In limestone about 5% mile southwest of the Nevada Mine, on
a sharp jagged hill about 200 feet high, just west of the exposure of white
igneous rock. Tonopah Quadrangle.

Loe. 2032. About 214 miles southwest of the Nevada Mine, at an elevation
of 6300 feet. Tonopah Quadrangle.

Transmitted August 24, 1914.

, by Louise Kellogg .......... f
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auna of the Martinez Eocene of California, by oe Ernest Dickerson ..............-.-.---- $1.25
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New Horses from the Miocene and Pliocene of California,

yee

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Etchegoin Fprmations in the North Coalinga Region, €

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The Owl Remains from Rancho La

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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Vol. 9, No. 14, pp. 199-214, plates 9-11 Issued February 24, 1916

FAUNA FROM THE LOWER PLIOCENE AT
JACALITOS CREEK AND WALTHAM
CANYON, FRESNO COUNTY,
CALIFORNIA

BY

JORGEN O. NOMLAND

CONTENTS
PAGE
JEsaNGSSCOXG BUC) sBlCOS 0. ees eee Ree OE ere ee ee 199
HEINIS GoM CeuMRAEUe Val Oly, giacees sree acs teas cu ceea ces eset eezdensevStece, /eceu¥s yete¥=cdta¢sebdoetacesdoleis lbsac¥eegeaevesss 200
Description of the Section on Jacalitos Creek 22.2.2... ces eceee cece eeeee eee 201
Fauna of the Lower Pliocene at Jacalitos Creek and Waltham Creek ............ 202
Palaeontologic Determination of Age of the Jacalitos Beds -........................- 204
DES Gi CLOM=O fe INiCWwa SDC CLCS cere eee eee eee eens eee 204
Astralium arnoldi, n. sp. ....---..----------- SE eee en 2 Lc 204
ChimySodomusyCOalimeensis,, M2 9S[ see cecesecaescececesceeeteeeegecae cee ce-eeteceeaeteeeeeeeeseeeeeeees) OS)
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INTRODUCTION

On approaching the eastern foothills of the Diablo Range about
seven miles southeast of Coalinga, California, the stratified deposits
are found to consist chiefly of soft beds of the lower and middle
Phocene. These strata comprise several thousand feet of much folded
and faulted sandstones and shales dipping away from the underlying
Cretaceous and Tertiary. In the mapping of this district by the
members of the United States Geological Survey the upper portion was

200 University of California Publications in Geology [ Vou. 9

correlated with the Etchegoin formation north of Coalinga, while the
lower part was given the formational name Jacalitos. This division
was based chiefly on palaeontologic evidence, as the two formations
wherever found in contact are apparently conformable. The fauna
obtamed from the Jacalitos was, however, small and the greater
number of the species listed either new or of very long range. As a
consequence the Jacalitos has been grouped with the underlying Santa
Margarita formation by some California palaeontologists and geologists
and with the overlying Etchegoin by others.

In the present paper a fauna of 82 species is listed. Although a
number of the species have a long range and a few are new, yet the
fauna seems large enough to fix the position of the beds of this lower
horizon on Jacalitos Creek and Waltham Creek more definitely in the
stratigraphic column than has been possible heretofore.

HIstoricAL REVIEW

The Neocene in this region was first described in a publication by
IF. M. Anderson,t who considered what has later been mapped as
Jacalitos and Etchegoin equivalent for the most part to the several“
hthological units grouped in what were called the Coalinga Beds, north
of the town of Coalinga. In a later paper the same author? restricted
his definition of the Coalinga Beds ‘‘to the lower portion of a series
which is unconformably related to the older members of the Miocene.’’
At what locality this oceurs or to what unconformity this has reference
is not known to the writer.

A report by Ralph Arnold’ on the palaeontology of the district
contains a brief description of the geology and advances evidence for
the separation of the Jacalitos from the adjoining formations.

In a bulletin dealing with the geology and oil resources of the
Coalinga district by Ralph Arnold and Robert Anderson* the Jacalitos
was described as being separable, at least faunally, from the Santa
Margarita and Etchegoin formations. In this publication overlap
was also used as evidence for the separation of the Jacalitos from the
Etchegoin. The section on Jacalitos Creek was taken as the type
section of the formation of that name, this being a part of the area
covered by the present paper.

1 Anderson, F. M., A Stratigraphic Study in the Mount Diablo Range of
California, Proe. Calif. Acad. Sci., 3d ser., vol. 2, no. 1, 1905.

2 Anderson, F. M., A Further Study in the Mount Diablo Range of California,
Proc. Calif. Acad. Sei., 4th ser., vol. 3, 1908.

3U. 8. Geol. Surv., Bull. 396, 1909.
4U. 8S. Geol. Surv., Bull. 398, 1910.

1916] Nomland: Fauna from the Lower Pliocene 201

In a recent paper written essentially to show the economic possi-
bilities of this region by R. W. Pack and W. English’ the Jacalitos
and Etchegoin are grouped together as upper Miocene. In this paper,
however, no faunal study is given of the relation of the Jacalitos to
the other formations.

DESCRIPTION OF THE SECTION ON JACALITOS CREEK

The present paper is a study of the type section of Arnold and
Anderson on Jacalitos Creek, and of the beds on Jasper Creek and
Waltham Creek which are traceable directly into the type section.
The description of the lithology and fauna may therefore be taken
as representative of the Jacalitos at the type locality.

The area studied has in late geologic time been subjected to numer-
ous structural disturbances. Tangential stresses have caused the beds
to be folded into open anticlines and synelines. The axes of these
folds are generally parallel to the major structural features of the
district. A fault zone having a northwest-southeast trend cutting
across the Diablo Range has greatly complicated the structure. This
fault zone has the same general direction as the San Andreas fault
a few miles to the west. Cross-faults are also numerous. These are,
however, usually not of as great magnitude as those in a northwest-
southeast direction. Due to faulting, some of the Tertiary formations
are not exposed for considerable intervals. Both the determination
of drainage lines and the elimination of formations by faulting are
well shown along the upper part of Jacalitos Creek. For several
miles this creek follows a fault of comparatively recent age, displacing
the Santa Margarita(?) and the lowest portion of the Jacalitos beds.
On following this in some places the lowest Jacalitos is found to be
absent, while in others the Santa Margarita(?) shale has been entirely
faulted out.

According to Arnold and Anderson, the thickness of the Jacalitos
beds exposed at Jacalitos Creek is 3800 feet. The thickness of the
section measured by them is probably too great, as beds apparently
of Santa Margarita(?) age are included in it. The separation of these
beds would, however, diminish the total thickness but slightly, the
Santa Margarita(?) having an exposure of only a few hundred feet.

On Jacalitos Creek the Phocene strata comprise essentially an
alternation of soft coarse sandstone and conglomerate. In many of

5 U.S. Geol. Surv., Bull. 581-D, 1914.

202 University of California Publications in Geology [ VoL. 9

the fossiliferous horizons the beds have been much indurated, causing
these strata to outcrop prominently. Of minor importance are shale,
rhyolitie tuff, and thin layers of coal. A bed of silicious limestone
having a thickness of about ten feet was traced more than one-half mile
until cut off by faulting. A short distanee above and below the lime-
stone marine fossils were found. The beds of coal, the coarseness of
the sandstones and conglomerates, the variation of the lithology within
short distances, and the character of the mulluscan fauna may be
taken as indicative of deposition under shallow water conditions. The
occurrence of quantities of gypsum at some localities, if it ean be
proved to be interstratified with the clastic rocks, may indicate that
in part the beds are terrestrial or that the basin of deposition was
nearly isolated from the sea.

FAUNA OF THE LOWER PLIOCENE ON JACALITOS CREEK AND

WALTHAM CREEK

In the lower 800 to 1500 feet of the Jacalitos fossils are rare
and where they appear the state of preservation is such that no
diagnostic fauna has been obtained. In the upper horizons at some
localities fossils occur in abundance. In most instances, however, the
character of the material is not ideal for the preservation of the smaller
forms, or the mullusean shells have been crushed or leached out. In
some parts of the area numerous faults limit the tracing of fossil
horizons except for short distances. At a few localities the prominent
indurated beds can be followed, otherwise the striking bands of white
tuff, where present, are the best horizon markers.

The following list comprises the fauna obtained in the beds that
have been mapped as Jacalitos at the type locality and the beds of
corresponding age on Waltham Creek.

ECHINODERMATA
Astrodapsis jacalitosensis Arnold
Astrodapsis peltoides Anderson and Martin
Echinarachnius gibbsii (Rémond)

PELECYPODA
Arca trilineata Conrad Cryptomya californica (Conrad)
Cardium quadrigenarium Conrad Cryptomya quadrata Arnold
Chione elsmerensis English Cumingia, cf. californica Conrad

Chione, ef. fernandoensis English Cyrena californica Gabb

1916]

Nomland: Fauna from the Lower Pliocene 203

Diplodonta parilis (Conrad)

Dosinia jacalitosana Arnold

Glyeimeris coalingensis Arnold

Glyeimeris septentrionalis (Mid-
dendorf)

Macoma baltica (Linne)

Macoma jacalitosana Arnold

Macoma nasuta (Conrad)

Macoma secta (Conrad)

Macoma vanvlecki Arnold

Metis alta (Conrad)

Modiolus rectus Conrad

Monia machroschisma (Deshayes)

Mulinia densata Conrad

Mytilus coalingensis Arnold

Mytilus kewi, n. sp.

Ostrea atwoodi Gabb

Pandora punctata Conrad

Panope generosa Gould

Paphia jacalitosensis Arnold

Paphia staminea (Conrad)
Paphia tenerrima (Carpenter)
Paphia, n. sp.?

GASTROPODA

Astralium arnoldi, n. sp.
Calliostoma coalingensis Arnold
Calliostoma kerri Arnold
Calyptraea filosa (Gabb)
Cancellaria, ef. tritonidea Gabb
Chrysodomus coalingensis, n. sp.
Chrysodomus imperialis Dall
Chrysodomus portolaensis (Arnold)
Crepidula aduneca Sowerby
Crepidula princeps Conrad

Ficus nodiferous Gabb

Fissuridea subelliptica, n. sp.
Margarita johnsoni Arnold
Murex perangulatus, n. sp.

Nassa californica (Conrad)
Natica (Neverita) recluziana Petit
Natica (Neverita) orbicularis, n. sp.

CIRRIPEDIA

Balanus, ef. concavus Bronn
Tamiosoma, ef. gregaria Conrad

Pecten estrellanus Conrad, var.
terminus Arnold

Pecten (Hinnites) giganteus
(Gray)

Pecten oweni Arnold

Peeten wattsi Arnold

Periploma, ef. argentaria Conrad

Phacoides annulatus (Reeve)

Phaecoides richthofeni (Gabb)

Sanguinolaria nuttalli Conrad

Saxidomus nuttalli Conrad

Schizothaerus nuttalli (Conrad)

Siliqua lucida (Conrad)

Solen sicarius Gould

Spisula albaria (Conrad)

Spisula coalingensis (Arnold)

Spisula hemphiili (Dall)

Tellina aragonia Dall

Tivela trigonalis, n. sp.

Yoldia cooperi Gabb

Zirphaea, cf, dentata Gabb

Olivella biplicata Sowerby

Purpura turris Nomland

Sinum secopulosum Conrad

Thais kettlemanensis Arnold

Thais lamellosa (Gmelin)

Trophon coalingense Arnold

Trophon magister, n. sp.

Trophon, ef. carisaensis F. M.

Anderson

Turris (Bathytoma) carpenteriana
(Gabb)

Turris (Bathytoma) coalingensis
(Arnold)

Turris (Bathytoma) tryoniana
(Gabb)

Turritella nova, n. sp.

Some of the forms in the Jacalitos fauna listed above warrant further

cliscussion.

Astrodapsis jacalitosensis Arnold, which has been thought

characteristic of the middle Jacalitos, has been found within 200 feet

of the top of the beds mapped by Arnold and Anderson.

Pecten owent

204 University of California Publications in Geology [ Vou. 9

Arnold, Pecten estrellanus Conrad var. terminus Arnold, and Echina-
rachnius gibbsii Rémond have been found to have a range extending
throughout the fossiliferous portion of the beds. A large number of
species thought not to extend below the Etchegoin have been found
to be of frequent occurrence in the Jacalitos. Among others may be
mentioned Turris (Bathytoma) coalingensis (Arnold), Trophon coal-
ingensis Arnold, Calliostoma coalingensis Arnold. Pecten wattsi
Arnold, which has been considered characteristic of the beds of
Etchegoin age, has been found at one locality well down in the Jacalitos.

PALAEONTOLOGIC DETERMINATION OF AGE OF THE JACALITOS BEDS

By increasing the Jacalitos fauna from 37 specifically determined
forms to 82, the number listed in this paper, the close relationship of
the Etchegoin and Jacalitos at once becomes apparent. Fifty-nine
of the species listed in this paper are known to be present in the
Etchegoin or younger formations. Twenty-six species are found also
in the Santa Margarita-San Pablo and these are chiefly forms of long
range.

The probable Pliocene age of the Jacalitos and Etchegoin has
already been shown by the work of Professor J. C. Merriam® and the
writer’ for beds of corresponding age north of Coalinga.

DESCRIPTION OF SPECIES
ASTRALIUM ARNOLDI, n. sp.
Plate 10, figures 2a, 2b

Shell heavy, moderately elevated, five or more whorls, slightly
convex at shoulder and periphery. Ornamented by about seven spiral
cords, of which the anterior two are the heaviest. Incremental lines
well defined, unequal; the crossing of these by spiral sculpture gives the
shell a nodose appearance. A wide suleus occurs between the lower
of the heavy anterior cords and suture. Aperture oval, with thin outer
lip. Base flattish, with about twelve nodose cords and wider inter-
spaces. Umbilical region imperforate, concave, with peripheral and
low median ridges. Dimensions of type: height, 48 mm.; maximum

diameter, 48 mm.; minimum diameter, 38 mm.

6 Merriam, J. C., Tertiary Vertebrate Faunas of the North Coalinga Region,
Trans. Am. Philos. Soc., vol. 22, part 3, Philadelphia, 1915.

7 Univ. Calif. Publ. Dept. Geol., vol. 9, no. 6, 1916.

1916] Nomland: Fauna from the Lower Pliocene 205

Occurrence.—Type specimen from University of California locality
2523, on low hill immediately north of road from Alealde to Robert’s
ranch, SE \, see. 27, T. 218, R. 14 E, M. D. B. & M.

Associated with this form at the type locality are, among others,
Monia macroschisma Deshayes, Pecten estrellanus Conrad var. termi-
nus Arnold, Pecten owent Arnold, Phacoides annulatus Reeve.

CHRYSODOMUS COALINGENSIS, n. sp.
Plate 10, figure 3

Shell fusiform, slender, seven or more whorls, spire high and acute.
Axially sculptured with sharp longitudinal ribs extending from
shoulder nearly to suture. Penultimate whorl with eleven ribs; on
the body whorl axial ribs almost absent. Spiral sculpture on the
upper whorls consisting of about seven prominent, nearly equal ribs
with interspaces less than tops of ribs. Aperture narrow. Canal
long, straight, thickened at base. Body whorl subangulate at shoulder,
with side of whorl slightly convex, ornamented with about seventeen
spiral ribs. Dimensions of type: height, 48 mm.; width, 17 mm.

This species may be easily distinguished from other members of
the same genus by its slenderness, the high spire, and the long canal
which widens near the base.

Occurrence.—University of California locality 2670, near top of
1600-foot hill, NW 14 sec. 34, T. 218, R. 14 E, M.D. B. & M.

FISSURIDEA SUBELLIPTICA, n. sp.
Plate 10, figures 5a, 5b

Shell subelliptical, moderately elevated, gently convex, apex
shehtly anterior. Radially sculptured by numerous equal ribs. On
type specimen concentric growth lines prominent, some more devel-
oped than others. Apical orifice large, elliptical, anterior to apex.
Dimensions of type: height, 24 mm.; maximum diameter, 56 mm.;
minimum diameter, 46 mm.

Occurrence.—University of California locality 2664, NE corner of
NW J, sec. 34, T. 2158, R. 14 E, M.D. B.& M.

At the type locality this species occurs with the following charac-
teristic lower Pliocene species: Phacoides annulatus (Reeve), Pecten
owent Arnold, Cancellaria, ef. tritonidea Gabb, Chrysodomus porto-
laensis Arnold, Turris (Bathytoma) coalingensis (Arnold), Turritella

nova, Ni. Sp.

206 University of California Publications in Geology [ Vou. 9

MUREX PERANGULATUS, n. sp.
Plate 11, figures la, 1b

Shell heavy, six or seven whorls, with three prominent thick varices
which are continuous from body whorl up the spire. Spire low with
indistinct sightly appressed suture. Spiral sculpture consisting of (on
the body whorl seven and on the others two) prominent somewhat
nodose ribs, on last whorl an interealary oceurs between each pair.
Canal open, straight. Outer lip slightly thickened, margin sharp,
internal spiral lines continue to edge, anterior part projects about
5mm. in front of columella. Inner lip smooth, columella imperforate.
Dimensions of type: height, 45 mm.; width, 27 mm.

This species resembles somewhat Purpura foliata Martyn, but dif-
fers in having apparently no anterior tooth or spine characteristic of
that genus, open canal, a low spire, and a projecting and not as much
thickened outer lip.

Occurrence.—University of California locality 2649, on ridge above
Coalinga-Priest Valley road, SE 14 sec. 19, T. 21 S, R. 14 E, M. D. B.
& M.

MYTILUS KEWI, n. sp.
Plate 9, figure 1

Shell elongate ovate, of moderate thickness. Surface sculptured
by numerous unequal incremental lines and minute radiating striae.
A wide depressed area passes from slightly above the beak to about
middle of base. Beak terminal, somewhat curved. Posterior end
regularly rounded. Posterior dorsal margin slightly areuate, with
small angulation a little more than one-half of the distance from the
beaks to the anterior end. Base straight except slight arch where it
meets the depressed area. Dimensions of type, which is a small speci-
men: length, 86 mm.; height, 45 mm.; maximum diameter, 34 mm.

This species seems to be rather closely allied to Mytilus expansus
Arnold, which occurs in the lower Miocene. M. erpansus Arnold has,
however, a broader posterior outline and the depressed area is not as
well marked. M. kewi, n. sp., differs from M. coalingensis Arnold,
which also occurs in the Jaecalitos beds, by being smaller, having less
acute and not as much thickened beak, and in the depression extending
from beak to basal margin.

Occurrence.—University of California locality 2680, near top of
ridge at center of NW J4 sec. 8, T. 228, R. 15 E, M. D. B. & M.

1916] Nomland: Fauna from the Lower Pliocene

bo
Ss
a |

NATICA (NEVERITA) ORBICULARIS, n. sp.
Plate 10, figures 4a, 4b

Shell globular, heavy, about five or six whorls, spire slightly ele-
vated. Sculptured by unequal oblique incremental lines. Body whorls
large, with marked convexity at shoulder, giving sides and top a flat-
tened appearance. Aperture ovate, with slightly thickened outer lip.
Umbilicus partly covered by callus extending from lower portion of
inner lip to upper portion of outer lip, with a sharp angle near the
middle, and is marked by a deep groove about one-third of distance
from posterior end. Height, 38 mm.; maximum diameter, 44 mm.

This species differs from Neverita recluziana Petit by its more
flattened sides, dome-shaped spire, less callused umbilical area, and
greater convexity at shoulder of whorls.

Occurrence.—Found at numerous localities in the Jacalitos and
Etchegoin. Type from University of California locality 2679.

TIVELA TRIGONALIS, n. sp.
Plate 9, figures 2a, 2b, 2c

Shell thick, trigonal, inequilateral, equivalve. Umbones small, about
two-thirds of distance from anterior end. Base gently arcuate. An-
terior dorsal edge nearly straight, depressed. Anterior extremity
evenly rounded. Posterior dorsal margin straight, much thickened.
Posterior end bluntly rounded to subangulate. Three thick cardinal
teeth in each valve, the middle left bifid, anterior lateral of left valve
heavy. Nymph plates very prominent grooved. Height, 41 mm.;
width, 55 mm.

Although somewhat similar to the Recent Tivela stultorum Mawe,
T. trigonalis, n. sp., may easily be distinguished from that form by
being more inequilateral, thick, depressed posterior dorsal margin, and
greater prominence of nymph plates.

Occurrence.—Middle Jacalitos to lower Etchegoin, University of
California localities 2684, 2104.

TROPHON MAGISTER, n. sp.
Plate 11, figures 4a, 4b, 4c
Shell very large, robust, thick, height of spire variable. Whorls
five or more, slightly convex, with appressed suture. Body whorl
sharply angulated at base and shoulder, giving the top a tabulate

208 University of Califorma Publications in Geology [ VoL. 9

appearance. Kach whorl ornamented by nine or ten prominent varices,
which at angles of whorl produce nodes or short spines which become
stronger with age. Immediately under body whorl is a deep groove
or canal, in front of which the anterior portion of whorl protrudes.
Aperture large, angular, with simple outer lip. Canal long, recurved.
Height of imperfect type, 92 mm.; diameter, 70 mm.

This species has heretofore been identified as Trophon ponderosum
Gabb. From this it differs by much larger size, stronger angulation
at base of body whorl, longer canal, and in having the deep groove at
base of last whorl. Trophon carisaensis F. M. Anderson is apparently
a close relative of this form, but differs from Trophon magister, n. sp.,
in smaller size, more prominent upper and less prominent lower nodes
on body whorl, suture being higher up on posterior whorls, and the
smaller angle which the upper surface makes with the axis of shell.

Occurrence.—Type from University of California locality 2098,
NW 1 sec. 24, T. 218, R. 14 E, M. D. B. & M. This species occurs
commonly in the upper portion of the Jacalitos beds.

TURRITELLA NOVA, n. sp.
Plate 11, figure 3

Shell turreted, whorls flat, with well-defined depressed suture.
Between the two more prominent spiral ridges, but somewhat nearer
the upper is a narrow groove. Immediately above and also immedi-
ately below the suture is a low ridge. Between the low ridge above
the suture and the heavier of the two ridges near the middle of the
whorl is a wide groove, giving a distinctly excavated appearance to this
portion of the whorl. Diameter, 11 mm.; height unknown.

This form is decidedly similar to Turritella coopert Carpenter, of
which it is probably the precursor. It differs, however, in having the
narrow middle groove, the minor ridges near the suture, and the
excavated area at the lower part of the whorls.

Occurrence.—Type from University of California locality 2533,
NE ¥, sec. 29, T. 21S, R. 14 BE, M. D. B. & M., on west bank of
Waltham Canyon.

Associated with this species are found in the type locality Macoma
vanvlecki Arnold, Pecten estrellanus Conrad var. terminus Arnold,
Pecten owent Arnold, Cancellaria tritonidea Gabb, Ficus nodiferous
Gabb, Turris (Bathytoma) coalingensis Arnold, Thais kettlemanensis
Arnold, Turris (Bathytoma) tryoniana (Gabb).

Transmitted October 1, 1915.

1

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=

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-

EXPLANATION OF PLATE 9
All figures natural size
Mytilus kewi, n.sp. Exterior of imperfect left valve.
Tivela trigonalis, n. sp. Exterior of left valve.
Tivela trigonalis, n. sp. Interior view of right valve.
Tivela trigonalis, n.sp. Interior view of left valve.
Chione elsmerensis English. Exterior view.

Chione elsmerensis English. Interior view of left valve.

[210]

UNIV CALIF, PUBL, BULLE, DEPT. GEOL, [NOMLAND] VOL. 9, PL. 9

EXPLANATION OF PLATE 10

All figures natural size

Chione elsmerensis English. Interior view of right valve.
Astralium arnoldi, n. sp. Upright view of imperfect specimen.
Astralium arnoldi, n.sp. Basal view.

Chrysodomus coalingensis, n. sp. Back view.

Natica (Neverita) orbicularis, n. sp. Back view.

Natica (Neverita) orbicularis, n.sp. Basal view.

Fissuridea subelliptica, n. sp. View from above.

Fissuridea subelliptica, n. sp. View in profile.

UNIVE “CALIF, PUBL, BUILE DEPT. GEOL. [NOMLAND] VOL. 9, PL. 10

; 2
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EXPLANATION OF PLATE 11

All figures natural size
Murex perangulatas, un. sp. Mouth view of type.
Murex perangulatus, n.sp. Back view of same specimen.
Trophon coalingense Arnold. A small specimen.
Trophon coalingense Arnold. Mouth view of a young specimen.
Turritella nova, n. sp. Type specimen.
Trophon magister, n.sp. Back view of type specimen.
Trophon magister, n. sp. Back view of a small specimen.

Trophon magister, n. sp. An extreme variation of this species.

[214]

VINIVS (CALIF, PUBL. BULL, “DEPT, GEOL. [NOMLAND] VOL. 9, PL. II

of the Weouterey. ae 2,
ia, by Louise Kellogg See ey Tula = kaa te a ee aa

eries in California, by George Davis Lodderteek’ = Sr Re ee hoe
tary Notes on Fossil Sharks, by David Starr Jordan and Carl Hugh Beal ..

the Bocene at Marysville Buttes, California, by Roy E. Dickerson ..........

and Dentition of a Camel from the Pleistocene of Rancho La Brea, by
. erriam be nae enans sadqdecnecnennecaueercasnanenncsescnussanecscnnedenasccecennsnensanshessnsn=tuance=-senenesancdcenssease
Petrographic Designation of Alluvial Fan Formations, by Andrew C. Lawson....
eeuliar Horn or Antler from the Mohave Miocene of California, by John C. Mer-

fietarotheviam and Megalonyx from the Pleistocene of Southern California, by

tes on the Canid Genus Tephrocyon, by John C. Merriam ........-s:ss-sscessoeeceseeeceeeseeseeee
fertebrate Fauna of the Orindan and Siestan Beds in Middle California, by John

TRIG nT oe, aS ae RA ae eR ace eg ee Ra,
ent 0) servations on the Mode of Aceumiilation of the Pleistocene Bone pegs
anchomlia brea, by, Reeinald Gs Storeng. cleo. .cc a sceeeaces ctesosat ewan
Preliminary Report on the Horses of Rancho La Brea, by John C. Merriam ............
Anchitheriine Horses from the wae of the Great Basin Area, by John C.

a ae Birnie Ce lert i arin ters ek Ok eee NS cl ae
tocene Beds at Manix in the Eastern Mohave Desert Region, by John P.

ryan Git Zia OS eee een ae aie AM RNa FS aoe amends
j cy Problem of Aquatic Adaptation in the Carnivora, as Illustrated in une Oste-
ry ology and Evolution of the Sea-Otter, by Walter P. Taylor atin: estate. cbs nanee meee. ac eareaee

the Boulder ‘‘Batholith’’ a Laccolith? <A Problata in Ore-Genesis, by Andrew

BRUNE EENS OF esate 8 cas ee sc sean oo tonat eu cn Seccxecmeutosd ae esaactdptbeatuty oxo eatertactSosntiecot Sh ocansuy dene tibaecobs cnaeeoee

te ‘on the Faunal Zones of the Tejon Group, by Roy E. Dickerson ........-....-----.----

eeth of a Cestraciont Shark from the Upper Triassic of Northern California, by
_ TRS OL GE Co TES any Theatre a mia ae eet Pega eee aren oe feet IS, RNR Ae

ird Sees from the Pleistocene of San Pedro, California, by Loye Holmes Miller.
ti

Sia, Dye nuce Mian time oie cce ae ee ee ote ie el ete ai et Oe Baa
‘he Fernando Group near Newhall, California, by Walter A. 1 Obie GSH a cso ee
re Deposition in and near Intrusive Hockey Meteorie Waters, by Andrew C.

ME AYN SOT eee a ronde fea nso) occnankstte can tenccntcectosqaiacas st nesedctenaduccenapscbssacesesonucnnestececneseonieecbest neue} ocoss
d The Agasoma-like Gastropods of the Galifonnia Tertiary, by Walter A, English......
‘he Martinez and Tejon Eocene and Associated Formations of the Santa Ana
Beuionmtatricne by hiow Ere MiCKkeTSOMs <22.8. 2. o..ccc ee eonseecctetc ree Meewannec cen caqacsbneonseartateaeadbeedacee
The Occurrence of Tertiary Mammalian Remains in Northeastern Nevada, by John
EC: * Merriam coach tr, Uae mn RS a eh
mains of Land Mammals from Marine Tertiary Beds in the Tejon Hills, Cali-
ornia, Dy John C. Merriam ..W....0.....ecseecseneseseeenssneesseeraveosssseesesssssnneenesceesnesseetnerenecovetinnane

Border of the Mohave Desert im by ee E. Dickerson | souethop As ast abe Ie Reape
ww Molluscan Species from the Martinez Eocene of Southern California, by Roy
MBN Ol ers er paetee a ape Oe ele ne A ae | oe
oo ‘Tooth from the ‘irucicee” Beds of Western Nevada, by John P.
UNC A Tatts sire ee NA sey a UN AN Me hee gee, Mase Sotces scuucn dt anatelised oe toot aus eaaencattcrtucee earns
fotes on the Copper Ores at Ely, Nevada, by AlfredhR. Whitman ...../2..----jc.teeccaee
cull and Dentition of the Mylodont Sloths of Rancho La Brea, by Chester Stock.
Pertiary Mammal Beds of Stewart and Ione Valleys in West-Central Nevada, by
EE DET ace. ee SS aati oe he ee Co eC 7
iary Echinoids from the ie Pablo Group of Middle California, by William Ss.

Oceurrence of WMainnalian Remains in a Pleistocene Lake Deposit at Astor
Pass, near Pyramid Lake, Nevada, by John C. Merriam ................s-cssseeececeeceeceeeeeee

¥
r

Index i in press, —

Seutella norrisi‘and Scutaster ideraue by Robert W. Pack................-. is:

(oR Sa Ci aa am EE EEC Se SAMO ng ee ee Pere MOORS ae

ey epme of the San Pablo Group of Middle California, by Bruce L. Clark..............

20¢°

. Corals from the Cretaceous and Tertiary of California a

. Relations of the Invertebrate to the Vert rate auna

po cael

10.
alii
12.
13.
14.

. The Epigene Profiles of th

. Two Vulturid Raptors from the Pleistocene of Rancho La Brea, by L

Desert, by ‘And Oh 3
New Horses from the Miocene and Pliocene of Calltarnia,

Etchegoin Formations in the North Coalinga, Region, C;

World e . seciiiscoe, nn s ape Bate aca sean Spee Meee ae oe ~
A Review of the Species Pavo californicus, by Loye Holmes ‘iler .
The Owl Remains from Rancho La Brea, by Loye Holmes M ‘pee say

A Cd EV ee ee ME eA OP eRe ne oe tA TR ek
Notes on Capromeryx Material from the Pleistocene of Rancho La:
CRAB OR os one ntee hiss nee as ee aa Re eR
A Study of the Skull and Dentition of Bisow antiquus Leidy, with
to Material from the Pacific Coast, by Asa OC. Chandler _......
Faunal Studies in the Cretaceous of the Santa Ana Mountains of &
fornia, by Marl Leroy Packard! Jjejhic) 2 See en eyes oe ee eee
Tertiary Vertebrate Fauna from the Cedar Mountain Region of W
ny? PohimC.> Merriam: bi) 2 ae a 2 ee eae ee
Fauna from the Lower Pliocene at Jacalitos Creek and Wa
County, California, by Jorgen O. Nomland -0.6...22.-cece-cccenecedeccececescnoeeeen 3

N OF THE DEP RTMENT OF.
“GEOLOGY. .
bre Issued February 29, 1916

THE PLIOCENE OF MIDDLE AND ie
NORTHERN CALIFORNIA

Cj ea ; ; BY

BRUCE MARTIN : ou ip i

bee
4
ets - By ci
4
us + —< > ie
ate MA. _ ad
: on
—
x

UNIVERSITY OF CALIFORNIA PRESS
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volumes § and following, $5.00. ed ,
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A list of titles in volumes 1 to 5 will be ve upon request.

VOLUME 6. | a

1. The Condor-like Vultures of Rancho La Brea, Wy Loye Holmes ; Miller. we ie See oe
2. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern
Nevada, by John C, Merriam. Part I—Geologic History.............-- Mel

3. The Geology of the Sargent Oil Field, by William F. Jones. |./sen. oe 5
4, Additions to the Avifauna of the Pleistocene Deposits at Fossil Lake, Oregon, by

Loye Holmes Maller... cyan oa cin wis Sietugeiein > wilh sfis'e tole ie’ st s/ats mila fetes ane

5. The Geomorphogeny of the Sierra Nevada Northeast of Lake Tahoe, by John A. Reid

6. Note on a Gigantic Bear from the Pleistocene of Rancho La Brea, by John C, |
Merriam.

7. A Collection of Mammalian Remains from Tertiary Beds on the Mohave Desert,
by John C. Merriam. Peis:

Nos. 6 dnd’ 7 im OMe COWOT. 6-6. oti oi eee, sjarelbis pelea lores [ol ele « T0e
8. The Stratigraphic and Faunal Relations of the Martinez Formations to the Chico
and Tejon North of Mount Diablo, by Roy E. Dickerson...................

9. Neocolemanite, a Variety of Colemanite, and Howlite from DAMES Los Angeles ¥
County, California, by :Arthup, 8.) Hakkle ...¥. ff... fora « alerbi= )> old ule ee et

16. A New Antelope from the Pleistocene of Rancho La Brea, by Walter P. Taylor..-

li. Tertiary Mammal Beds of Virgin Valley and Thousand Creek in Northwestern
Nevada, by John C. Merriam. Part TI.—Voertebrate Faunas.........+.++ fae

12. A Series of Eagle Tarsi from the Pleistocene of Rancho La Brea, by Loye Helmes -
Maier, ays aie Silas oh tie ic 5s oils Rte Soemiefeuatnile <n; Suaks > =» AMRRN USTs cathe oh ve a waehets vs

13. Notes on the Relationships of the Marine Saurian Fauna Deseribed from the Triassic * coe

of Spitzbergen by Wiman, by John C. Merriam. a
14. Notes on the Dentition of Omphalosaurus, by John C. Merriam and Heete C, Bryant. s
Nos: 13 ,an@ 14, 18- One COVELne' .c. esc + Pee ayslaerecie Gate vaca ee ola ie oth ea
15. Notes on the Later Cenozoic History of the Mohave Desert Region in Southeastern es

California, by Charles Laurence Baker... 2... .iicjseisc dele ae © <1h)s-teienen nee
16, Avifauna of the Pleistocene Cave Deposits of California, by Loye Holmes Miller
17, A Fossil Beaver from the Kettleman Hills, California, by Louise Kellogg........
18. Notes on the Genus Desmostylus of Marsh, by John C. Merriam........ a sisi oot
19. The Elastic-Rebound Theory of Earthquakes, by Harry Fielding ioe Se: tee

,

VOLUME 7. rae

1. The Minerals of Tonopah, Nevada, by Arthur S. Eakle............. etme

2. Pseudostratification in Santa Barbara County, California, by. George Davis
Dae 6: ails « diva Y Wie keds aiden elie bi boas Boo a che, Weis CeRRne Ee Maats viene ome Re

3. Recent Discoveries of Carnivora in ie Pleistocene of Rancho La ah “John Y
Merriam! 5 )oeyeia's ood te Fas batts Wie Bei iseleere © lee, heel ee ae {og Se

4, The Neocene Section at Kirker Pass on the North Side of Mount Dial Ice
De Clamle Paves’ fete «heb ieie veg eye atetepelet, aibyal.s can: 4 Unease oan

5. Contributions to Avian Palaeontology Pa the Pavifie Roe eis, North
Loye Holmes Miller : 3 :

AG ee seed ee ek

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Vol. 9, No. 15, pp. 215-259 Issued February 29, 1916

THE PLIOCENE OF MIDDLE AND NORTHERN
CALIFORNIA

BY
BRUCE MARTIN

CONTENTS

PAGE

NED aULEy eXOY LUI es Kp 0 epee NE: = cy xR CB Oo OSCR 215
Neve wasOb thes Titenat Utes: 2 c.seets ee socccecese saecs decenees ss. case cee cecedzonlosnesacecsesesazsasees2 216
WER COMES CTLGS peteecberrc cece hort ener gh ane ee nee care eet ae pacts iY, Gee eee Bea 222
Merced: of the Type Locality: nc...2c.2220222.cnecccccccscces ccctcsdctetcccassnecectiecccasceseceaeass, DLO
Merced of Bolinas Bay 200...00..2.200........------------2-2-2--eeeeeeeeeeeeeeeeeeeeeeteeeeeseeeeeeeeeeeeeeees 230
Merncediot “Amon INUWeV.O) (Bary coos teeecece eee waecatenees oeee ene ceeeeeeee scctcen co caceseneseuecwseecuees 230
Mercedsot sPillam (Pointy... 3:2. 2c 2cecceeeece sencsecceccsscetadeceeleaceteczezssobde sae seus ocdbbcas oe 231
Merced iol thet Sareemt Oi Hel Wee cscs enc rere see ee ance cess eee ec 232
Mercedaof ther Santa, (Rosai Vall ey -.-5.2- es 2ccczactecedecec cece ee ceccsccenccacectececcecedeens=2 233
BVVplil GG ea ee S Ta CS erence cc ne een ares MeN SR vaca e eee ON ee ae 234
APE SU GapIMH CBU C Siero ee eran ew Rh eS eco Se ee ee 234
EOE O GE a eI Wn re REE 7-13)
Wpper Miocene of Bear: River. .....2.22.-2---csccelesecsccecnsenceccccnenecesevncceceesenneccccuceseeneeceece 240
TEXTE SUT oa 0 ET a 0 Ue pee eee eo EU ES 241
Htchegoin of the Sargent Oil Pield............--..--.22.-----csccceeseesssesceccaseessencssenntenecennanee 244
Later Neocene and Quarternary Deposits of Cape Blanco, Oregon................ 245
COO ee S IE GOs 1a eer er eo .. 247

INTRODUCTION

Within the past two years the writer has examined a number
of the Pliocene formations of California for the purpose of bringing
together a more complete fauna than had heretofore been obtained,
hoping also to throw some light on the faunal relations of the
formations, and to make possible a more exact correlation of the
beds concerned. It is the purpose of this paper to give the results
obtained in this investigation. The formations included in the
examination are: the Merced Series at Seven Mile Beach, San
Mateo County, and at several other localities to the north and to

216 Unwersity of California Publications in Geology [Vor. 9

to the south; the Purisima Formation south of Halfmoon Bay, San
Mateo County; the later Neocene formations of the Sargent Oil
Field; and the Wildcat Series in Humboldt County, California.

REVIEW OF THE LITERATURE

Aside from the incidental references to the geology of the
Pacific Coast made by the early scientists and explorers, such as
Captain Beechey and others, there are numerous publications which
have contributed much to our knowledge of the later Tertiary and
Quaternary formations of this region. The more important of these
papers will be briefly reviewed in their chronological order.

Among the earhest publications is one by Dr. John B. Trask, in
which he discusses the geology of the Coast Range Mountains. In
this paper he defined the Santa Cruz Mountains and described the
geology of that region.t. He applied the name ‘‘infusorial group’’
to the shales now known as the Monterey shales. He described
slates and sandstones overlying the Monterey and found them fos-
siliferous. The latter are probably the beds that are now known
as the Purisima Formation.

In 1856 Dr. W. P. Blake published an account of the geology of
the San Francisco Bay region.? The stratigraphy and lithology
of the beds exposed along the shores adjacent to the Golden Gate
and of the islands in the bay were fully discussed. The series of
sediments were considered to be of Tertiary age from fragments
of rocks washed upon the beach, near Point Lobos, containing fossil
echinoderms (Scutella interlineata), which he supposed to be the
same rocks as those exposed at Point Lobos in place. The frag-
ments containing Scutella interlineata probably came from the Mer-
ced Series several miles farther south, which he apparently omitted
from the discussion.

In 1865-66 the Geological Survey of California made a survey
of the coast region from San Francisco Bay south to San Diego.’
The beds at Seven Mile Beach were called Pliocene, on the authority
of Gabb and Rémond, and were said to be overlain by Post-Pliocene
sediments. The formations exposed along the coast south of Half-

1 Senate Doc. no. 14, State of California, Session 1855.
2 Pacific Railroad Reports, vol. 5, pp. 145, 1856.
8 Geol. Survey of Calif., J. D. Whitney, State Geologist, Geol. vol. 1, p. 61.

1916] Martin: Pliocene of Middle and Northern California 217

moon Bay were classed as Miocene Tertiary, and those at Ano
Nuevo Bay as Pliocene.

A list of California fossils, together with their geological and
geographical range, was compiled and published in 1888 by Dr. J.
G. Cooper in the Seventh Annual Report of the State Mineralogist.*
In general the formations at Halfmoon Bay and Seven Mile Beach
were considered to be Phocene. Some of the beds between Half-
moon Bay and Santa Cruz were classed as Miocene.

In 1898 Professor A. C. Lawson published the first complete
description of the marine sediments at Seven Mile Beach and ap-
pled the name ‘‘ Merced Series.’”* In discussing this series Pro-
fessor Lawson described the structural and stratigraphic features
and the various lithological types. He also gave a faunal lst
which, according to Dall and Cooper, was indicative of the Pliocene.
The unconformable relations between the Merced Series and the
overlying brown and tawny sands designated the ‘‘Terrace Forma-
tions,’’ was briefly discussed. The beds at Pillar Point were in-
eluded in this discussion, and those south of Halfmoon Bay were
referred to.

During the same year Professor Lawson published his ‘‘Sketch
of the Geology of the San Francisco Peninsula,’’* in which he re-
viewed the previous work on the Merced Series and brought out more
strongly the proof of the fault along the south side of San Bruno
Mountain along which movement took place, letting the strata of
the Merced Series down against the rocks of the Franciscan Series
of which San Bruno Mountain is composed. This brought out more
clearly the stratigraphic relations of the whole series and the
structural origin of Merced Valley. A small addition was also
made to the faunal list which indicated the Pliocene age of this series.

During the summer of 1894 Professor Lawson made a recon-
naissance trip north along the coast from San Francisco to Eureka.?
The account of this trip contains a description of the Neocene sedi-
ments which occur in the Eel River Valley. The limits of the area
over which these beds occur was not defined, but two cross-sections
were made, one at Ferndale and the other at Scotia, giving the

4 Calif. State Mining Bureau, Seventh Annual Report of the State Mineral-
ogist, 1888.

5 Univ. Calif. Publ. Bull. Dept. Geol., vol. 1, pp. 115-160, 1893.

6U. S. Geol. Survey, Fifteenth Annual Report, p. 459, 1893.

7 Univ. Calif. Publ. Bull. Dept. Geol., vol. 1, p. 255, 1894.

218 University of California Publications in Geology [Von. 9

structure and the lithology of the formation. The name ‘‘ Wildcat
Series’? was applied to the beds, from their typical development
in the Wildcat country south of Ferndale. A collection of fossils
made by Professor Lawson, principally from the middle and upper
portions, and identified by Dr. J. C. Merriam, warranted the deter-
mination of these beds as Pliocene.

In 1895 George H. Ashley published an account of the Neocene
stratigraphy of the Santa Cruz Mountains.’ In this paper he re-
viewed the work of previous writers and gave the results of his
owh investigations, which appeared to show that the beds, now
known as the Purisima Formation, were very closely related to the
Merced Series at Seven Mile Beach, but contained more of the
Miocene forms and were therefore placed between the Miocene and
the Pliocene and were called the ‘‘Transition Beds.’’ Ashley also
suggested the possibility that the lower portion of the Merced Series
at Seven Mile Beach might have been faulted down, and that
this faulted portion was the equivalent of his ‘‘Transition Beds’’
south of Halfmoon Bay. He did not discover any widespread un-
conformity between the Monterey and the Merced Series, and was
of the opinion that sedimentation was continuous from the begin-
ning of Monterey time to the end of the Merced, the disturbances
which had effected this region taking place at the close of Merced
time. The uppermost Merced was placed in the Pliocene because of
the degree of folding to which it had been subjected and because it
was covered by later sediments, the terrace formations. He consid-
ered that the evidence was insufficient to establish an unconformity
between the upper and the lower portions of the Merced, although it
was apparent that either faulting had, taken place or an unconformity
existed in the neighborhood of Thornton Station.

The ‘‘Topographie Development of the Klamath Mountains
published by J. S. Diller in 1892 contains a condensed description
of the Tertiary and Quarternary formations occurring along the
coast of Oregon and California from the mouth of the Coquille
River to Cape Mendocino. The stratigraphy and the lithology
of the Wildcat Series was amply described. Inserted with Diller’s
description are notes by Dr. W. H. Dall concerning the age of the
beds. The Wild Cat was doubtfully considered upper Miocene, being

9910

8 Proc. Calif. Acad. Sci., 2nd series, vol. 5, 1895.
10 U. S. Geol. Surv. Bulletin, 196, p. 30, 1902.

1916] = Martin: Pliocene of Middle and Northern California 219

certainly younger than the Empire Beds of Coos Bay and older than
the Merced south of San Francisco. In a later note, inserted in
the same publication (page 39), Dr. Dall reported, after having
visited the region himself, ‘‘that the characteristics of the fauna
point to an upper Miocene age and no distinetly Pliocene species

ie,

of mollusks appear in it anywhere.’’ Some of the sands and gravels
toward the ocean appeared to be quite recent and it was considered
by Dall that these might even be Pleistocene. The deposition of
this series was considered continuous from the upper Miocene to some
time in the Phocene without a marked unconformity, ‘‘and with a
continuous fauna which changed, if at all, chiefly by some species
becoming more rare or disappearing entirely.”’

Along Mad River, between North Fork and the mouth of Canon
Creek, a formation of soft sandstone was exposed which formed
the low hills along the east side of the coastal plain. A small num-
ber of fossil marine mollusks obtained from these beds were identi-
fied by Dr. Dall, who questionably placed the beds in the Pliocene.

At Battery Point, near Crescent City, California, a section is
described at the base of which is a formation of soft bluish sand-
stone containing pebbles and a few fossil invertebrates, among them
Terebratalia hemphillr Dall, which points toward a Pliocene age.
Above this member there are non-fossiliferous yellowish sands and
clays with some pebbles at the base. The whole series is uncon-
formable above a much altered sandstone of Pre-Tertiary age.

A similar section is exposed at Pebble Beach, two miles north
of Crescent City. Here the bluish sandstone containing Terebratalia
hemphillt is apparently lacking, and the soft non-fossiliferous yel-
lowish sand is lying horizontally upon Miocene strata which were
tilted slightly to the northwest. The Miocene beds were unconform-
able upon the much altered Pre-Tertiary sandstone.

At Point St. George, a few miles north of Crescent City, Diller
described a formation of soft yellowish and gray shaly sandstone
and whitish shale, less than one hundred feet in thickness, which
contained a fauna that warranted its determination as Miocene of
the Empire horizon.

At Cape Blanco, Oregon, about forty miles north of the Califor-
nia boundary, Diller described Neocene and Quarternary sedi-
ments which are more or less closely related to the later Tertiary
formations of California. The Neocene is represented by a series
of yellow sandstones, tuff, light-gray sand beds, conglomerate, and

220 University of California Publications in Geology [Vor. 9

argillaceous sand with caleareous nodules. This series was named
the Cape Blanco Beds and correlated with the Empire of Coos Bay
on palaeontological evidence. This formation was reported to ex-
tend from Cape Blanco to the mouth of Elk River, where it was
seen to dip beneath the beach sand. The sediments also occur
along the chffs north of Black Lock Point. Overlying unconform-
ably the Cape Blanco Beds were a series of sands and gravels, the
lower portion of which was very fossiliferous. This series was
named the Elk River Beds. <A collection of fossils made by Diller
was submitted to Dr. Dall who made the following report: ‘‘They
are probably Pleistocene, all of the species seeming recent, but they
may be of the Merced horizon; they are not older than the newer
Pliocene.’’ Diller thought that the interval between the Cape
Blaneo Beds and the overlying Elk River Beds might represent a
long period and that the Merced and the Wildeat formations were
deposited during that time.

In 1903 Ralph Arnold published a memoir on the ‘palneontliee
and Stratigraphy of the Marine Pliocene and Pleistocene of San
Pedro, California.’’*? In this publication the author correlates a
number of the Pliocene and Quarternary formations along the coast
with those at San Pedro. The greater part of the Merced Series
is considered to be above the San Pedro and the San Diego Pliocene.

The Proceedings of the American Philosophical Society contains
an article by Haehl and Arnold which deals with the diabases of
the Santa Cruz Mountains.’? In this paper a new formation is de-
seribed to which the name Purisima is given. This formation con-
sists of conglomerates, fine-grained sandstones, and shales which
were typically developed in the vicinity of Purisima Creek, San
Mateo County, California. The beds were found to be unconform-
able upon the Vaqueros sandstone and the Monterey shale, and at
the top graded into beds having a fauna somewhat similar to that
of the Merced Formation. The individuality of the fauna, strati-
eraphy, and the lithology of this formation appeared to warrant
the application of a new and distinct name. The formation was
thought to represent the middle and the lower portion of the Phlocene.

In 1905 Vance Osmont described a geological section across the
coast ranges north of San Francisco Bay.’* In this section he re-

11 Calif. Acad. Sci., Memoirs, vol. 3, 1903.
12 Proc. Amer. Phil. Soc., vol. 43, pp. 22-24, 1904.
13 Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, pp. 39-87, 1905.

bo
_

1916] Martin: Pliocene of Middle and Northern California 2

ports the occurrence of marine Pliocene which he correlated with
the Merced Series at Seven Mile Beach, but thought that they might
represent the lower portion, such as the beds at Capitola, there
being an abundance of Arca trilineata Conrad. These beds were
resting upon a formation of voleanie ash, called by Osmont the
Sonoma Tuff. In some localities the tuff was associated with sand-
stones and conglomerates, and in other localities with lava flows.
Conformably beneath the Sonoma tuff occurred the Mark West
andesite. This series of formations, including the St. Helena rhyo-
lite which econformably overlies the Merced, rests uneconformably
upon the Orindan Formation. The fauna obtained from the marine
sediments, in the neighborhood of Wilson’s Ranch, seemed to war-
rant the correlation with the beds at Seven Mile Beach. The thick-
ness of the formation was in the neighborhood of two thousand feet.

In 1906 Ralph Arnold published a monograph on the Tertiary
and Quaternary Pectens of California.‘* In this publication the
author gives a short review of each of the typical formations of the
Tertiary and Quaternary of California. He included a faunal list
for each formation and correlated them on that basis. The greater
portion of the Purisima Formation was placed unquestionably in
the Pliocene, although the lower portion was closely related to the
Miocene. The Merced Series was both Pliocene and Pleistocene,
the greater portion being placed in the upper Pliocene. Both the
Purisima and the Merced horizons were recognized in the Wildcat
Series in Humboldt County.

The ‘‘Geologic Record of California,’’ a paper published in 1910
by Dr. J. P. Smith,® contains a correlation table which ineludes
formations from the Archaean to the present. The Merced Series
is placed in the upper Pliocene and the Purisima Formation in the
lower Pliocene and uppermost Miocene.

The geology of the Sargent Oil Field, Santa Clara County, Cali-
fornia, was worked out and published in 1911 by William F. Jones.1®
The formations concerned in the geology of this area include both
igneous and sedimentary from the Franciscan to the present. Only
the upper Miocene and the Pliocene are to be considered in this
paper. The Monterey shale is the most extensive and well developed
of the formations represented. Unconformably overlying the Mon-

14U. §. Geol. Surv. Professional Paper no. 47, 1906.
15 Journal of Geology, vol. 18, pp. 216-226, 1910.
16 Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, pp. 55-78, 1911.

222 Unwersity of California Publications in Geology [Vor. 9

terey there is a formation composed principally of coarse-grained
to conglomeratic sandstone, portions of which are azure blue in
color and somewhat resemble part of the San Pablo. On this char-
acter Jones has depended for its correlation with the San Pablo,
which name he has applied to the formation. Overlying his San
Pablo unconformably is his Merced and Purisima. This formation
is about fifteen hundred feet in thickness. It is composed principally
of medium and coarse-grained gray sandstone. The correlation of
this formation with the Merced and the Purisima was made upon
palaeontological evidence.

Dr. J. P. Smith has recently published a paper on the Miocene
invertebrate faunas of California.’* In this paper the author gives
a faunal list which inelude all of the species so far known from
these formations, together with the life range of each species. The
division between the Miocene and the Pliocene was drawn between
the Etchegoin and the Purisima as a matter of convenience, ‘‘there
*’ The Purisima
was placed with the San Diego Formation and classed as lower Plio-

being no natural boundary between the two periods.

cene. The Merced Series, together with the Santa Barbara, was con-
sidered to be upper Pliocene. The name Merced was not used in
connection with any of the formations in the south because it was not
certain that the term Merced Series was applicable to such formations,

Mercep SERIES

Aside from the Merced Series at Seven Mile Beach, there are,
in the vicinity of San Francisco Bay, numerous other occurrences
of marine sediments which have been recognized as being contem-
poraneous in deposition with those at the type locality, and to which
the name Merced has been applied. One of the largest of these
occurrences is to be found in the Santa Rosa Valley a few miles
north of the city of Santa Rosa. Another rather large area occurs
in the Pajaro River Valley near Sargent Station, Santa Clara
County, California. Three smaller areas are situated along the
coast, one at Ano Nuevo Bay, another at Pillar Point, and the third
at the entrance to Bolinas Bay. There are other marine sediments
in this general region, portions of which are the equivalent of the
Merced Series at Seven Mile Beach, but these formations have been

17 Proc. Calif. Acad. Sci., 4th series, vol. 3, pp. 161-182, 1912.

1916] = Martin: Pliocene of Middle and Northern California 223

described under another formation name. The general stratigraphic
and lithologic features of each formation will be briefly outlined
before the faunal correlation is attempted.

MERCED OF THE TYPE LOCALITY

Physical Features——The type section of the Merced Series occurs
on the San Francisco Peninsula about eight miles south of the
Golden Gate. The area covered by these beds lies in the form of
an elongate trapezoid extending diagonally across the peninsula
from Seven Mile Beach southeast to San Francisco Bay. The south-
western boundary is a nearly straight line. From Mussel Roek it
follows a course southeast to Lake San Andreas and thence east-
ward toward San Mateo. The northeastern limits of this area are
marked by a fault scarp along the south flanks of San Bruno
Ridge. Professor Lawson has shown that this fault searp, which
is somewhat obscured by the valley alluvium, is the line along
which movement took place, letting the Merced Series down against
the Franciscan of San Bruno Mountain, and that this downthrow,
along the northeastern border, gave the latter its monoclinal structure.

The general stratigraphic characters of these sediments were
described by Professor Lawson as follows:

From the basement at Mussel Rock the strata of the Merced Series are
well exposed in ascending sequence to Lake Merced. The edges of the strata
form the sea-cliff for the entire distance. The sea-cliff is in active recession,
so that fresh exposures of the rocks are afforded throughout the section.
The strike is for the most part more or less transverse to the shore, and
the latter is a simple, nearly straight line. The rocks are tilted, generally
at high angles, and have a monoclinal structure for the entire length of the
section. . . . There is no repetition of strata, and fault structure is rep-
resented only by very minor dislocations. In a word, the section is ideally
simple, and is eminently susceptible of approximately accurate measurement
for the thickness of the series. There is but one drawback, and that con-
sists of two landslides which scar the face of the cliff. . . . The cliff at its
highest is about 720 feet above the shore, and at several places the strata
may be seen extending from the shore to the top of the cliff with uniform
dip.18

These beds are resting upon the eroded surface of the Fran-
ciscan Series, which is a prominent formation in the Coast Range
Mountains. The contact between these two formations is marked
by a very distinct change in lithology and a very pronounced dif-

18 Lawson, A. C., Post-Pliocene Diastrophism of the Coast of California,
Univ. Calif. Publ. Bull. Dept. Geol., vol. 1, p. 148, 1893.

224 Unversity of California Publications in Geology [Vou. 9

ference in attitude of the strata. From Mussel Rock north to the
landslide at Thornton Station the beds have an average dip te the
northeast of fifty or sixty degrees. The strike for this section varies
between north forty and. north sixty degrees west. Beyond Thorton
Station the strike is nearly parallel to the cliff with a small east dip.
The sudden and marked change in the attitude of the strata at this
point commands more than the usual interest. The lithological char-
acter of the rocks appears not to be greatly different in the two sec-
tions, but the suggested stratigraphic discordance, together with the
faunal break, which will be discussed on a following page, suggests
the possibility of an unconformity, and warrant separation of the
series into an upper and a lower horizon.

The rocks of the Merced Series consist of fine-grained gray
sandstones and sandy shales, usually soft and friable, being little
more than compact sand. Occasionally thin, hard ecaleareous lay-
ers and thin lignitic layers are interstratified with the softer mate-
rial. In a few localities, near the base of the series, a small
amount of conglomerate was observed. With this exception the
sediments are principally fine-grained soft sandstone and clays.

One of the most remarkable lithological features of the whole
series is the occurrence of a large area of shell agglomerate in
the higher portions of the hills one and one-quarter miles south
and a little west of Baden Station. The strata are composed
almost entirely of fragments of marine shells. Fine sand and
eravel compose the ground-mass in which the shell fragments are
embedded. This deposit marks an, old beach line or littoral zone
and is important in showing the shallow-water conditions which
existed during a part of Merced time. The total thickness of the
Merced Series, as measured by Professor Lawson, amounts to a
little more than one mile.

The Merced Series is overlain, unconformably, by a belt of
nearly horizontal deposits which stretch entirely across the pen-
insula from the ocean beach to San Francisco Bay. These deposits
are composed principally of light-yellow and brown sands and
clays, with occasional seams of gravel and lignitic material near
the base. At least a part of these sediments were designated the
Terrace Formations by Professor Lawson in a publication to which
reference has previously been made. The term ‘‘Terrace Forma-
tions’’ as used in this publication may include more than was
originally included by Professor Lawson. Together with the allu-

1916] Martin: Pliocene of Middle and Northern California 225

vium and surface soils they entirely cover the floor of the Merced
Valley and extend far back on the hills to considerable elevations,
manteling a large portion of the Merced Series.

In general, the relations of the Terrace Formations to the
underlying series are obscure. Between the ocean beach and Lake
Mereed, north of Thornton Station, the strata of the upper horizon
of the Merced Series, the Gasteropod Zone, are only very gently
inclined toward the north and east. The overlying Terrace Forma-
tions are poorly stratified and it is a difficult matter to locate a
difference in attitude of the two formations. In the sea-cliff
about one mile south of the outlet to Lake Merced Professor Law-
son recognized an erosion surface. The occurrence of dark brown,
somewhat peaty, beds immediately above the erosion surface sug-
gested to Professor Lawson the possibility that this might mark
the base of the Terrace Formations.

In laying its track from San Francisco to Halfmoon Bay the
Ocean Shore Railroad Company has cut a bench in the sea-cliffs
from Thornton Station to Mussel Rock. A few hundred yards
south of Thornton Station the railroad cuts have exposed a good
section in which a distinct unconformity may be observed. This
uneonformity is marked by an erosion surface and a difference in
attitude of the strata. The beds above the erosion surface consist of
rather coarse sands, gravels, and clays. The underlying strata are a
part of the Merced Series and are probably the upper part of the
lower horizon instead of the upper horizon found north of Thornton
Station. This unconformity is considered to mark the base of the
Terrace Formations.

In following up any of the larger creeks which cut across the
strike of the strata of the Merced Series, south and southeast of
Colma, one usually finds the soft, unconsolidated, light-yellowish
sands and clays in the lower portions of the streams. The erosion
of these sediments is quite characteristic and resembles the Bad
Lands topography. The stratification is not well marked, but occa-
sionally bedding planes can be observed and they are usually hori-
zontal. In continuing up stream the gray sandy shales of the
Merced Series are encountered. The stratification of the latter is
inclined northward at considerable angles. At no place in these
sections is it possible to find the exact contact between the two
formations, but the zone of separation can be quite easily located.
It crosses the larger creeks at about the two hundred or two hun-

226 University of California Publications in Geology [Vor. 9

dred and fifty-foot contour line, or where the topography changes
abruptly from the gentle slopes of the Merced Valley to the steeper
slopes of the adjoining hills. The difference in the character of the
sediments, the difference in attitude of the strata, together with the
fact that they are in places separated by an erosion surface, makes
it clear that the Terrace Formations and the later Quarternary
deposits are lying unconformably upon the Merced Series.

The upper horizon of the Merced Series has not been recognized
in the sections south and southeast of Colma. Its absence from
these sections may be explained by considering that a portion of
the Merced Series (that portion south and southeast of Colma) was
being subjected to erosion while the upper horizon, north of Thorn-
ton Station, was being deposited.

The Terrace Formations consist principally of light-yellowish
sands and clays. There are numerous seams of gravel and coarse
sand interstratified with the finer sediments. Lignitie material and
well-preserved pieces of wood are not uncommon in the basal por-
tion of the series. One of the most noteworthy occurrences of
wood may be observed in the banks of one of the larger creeks
one mile nearly due south of Colma. Here the trunks of large
trees project out of the creek banks, in some cases extending across
the creek into the opposite bank. These trees are buried beneath
several hundred feet of sediments. In nearby streams the strata
of the Merced Series outcrops in the creek bottom, indicating that
the trees occur near the base of the Terrace Formations or later
Quaternary deposits. It seems probable that they existed on the
land surface of the Merced Series prior to the deposition of the
later sediments. The origin of these formations is to be accounted
for in a number of ways. It is the opinion of the writer that
they are not to any extent marine deposits, but that they are
mainly sediments that have been deposited in swamps, lagoons,
and in fresh-water lakes; and to a less extent, are alluvial wash
and sand-dune accumulation. They are the equivalent of at least
a portion of the Santa Clara Formation and the Quaternary
gravels overlying the Santa Clara Formation.

Fauna—tThe fauna of the Merced Series, of the type section,
has not generally been considered to be distinctly determinative.
This has been due to the absence of certain eharacteristic forms,
such as the pectens, which are frequently relied upon to a great
extent as horizon determiners. The collections of Cooper, Lawson,

1916] = Martin: Pliocene of Middle and Northern California 227

Ashley and others have usually been characteristic enough to
justify the determination as Pliocene, but they have not been suffi-
cient to assign any particular part of the Merced to a certain
division of the Pliocene. Some palaeontologists who are familiar
with California geology have considered the series to be upper Plio-
cene. The reasons for such a determination are to be found in the
relation which the Merced bears to formations outside of the area
rather than the fauna found within the Merced itself. At Ano
Nuevo Bay, a short distance to the south, a small area of Merced
is reported to occur conformably above the Purisima Formation. The
faunal and stratigraphic relations of the Purisima appear to indicate
that it is lower Plhocene in age. From the superposition of the
Merced upon the Purisima it is evident that the Merced is at least
later than lower Pliocene.

Recent collecting over the whole area covered by the Merced
has revealed fossil invertebrates from the entire vertical range and
also from the greater portion of its lateral extent. Numerous
ereeks and small streams cut transversely across the section from
its southwestern boundary to the Merced Valley. In nearly every
one of these streams good exposures are to be found, and fossil
localities, while not numerous, are usually found in all of these
sections. The hills immediately to the southwest of Millbrae have
afforded several localities from which a large number of fossil
leaves were obtained, as well as fossil invertebrates. Unfortunately
the generic and specific character of the leaves could not be de-
termined, consequently they give no evidence as to the age of the
beds in which they were found. They are of value, however, in
showing the character of the deposit, clearly defining it as an
estuarine or littoral zone. To the southeast of Millbrae good
exposures rarely occur on account of the alluvium and sand-dune
deposits which conceal the underlying beds. To the northwest the
outcrops become much more numerous and accessible, and the state
of preservation of the fossils much better as the ocean beach is
approached.

The most satisfactory and accessible section for a faunal study
is the one exposed along the sea-cliff from Mussel Rock to the out-
let of Lake Merced. In general, fossil localities are not as numer-
ous as those found in other sections, but the excellent exposures
of the strata afford good opportunities for investigation. Near
the base, just above the contact at Mussel Rock, several localities

228 University of California Publications in Geology [Vou. 9

have yielded as high as fifteen or twenty species. Occurring as
they do at this locality they are of more than usual value. <A short.
distance south of Thornton Station, on the Ocean Shore Railroad,
a number of hard coneretionary strata occur interstratified with
softer material. In these strata numerous well-preserved echino-
derms, Scutella interlineata Stimpson, occur. They are also numer-
ous in the localities a short distance above the base of the section,
but so far as the writer’s experience goes they have not been found
above the locality a few hundred yards south of Thornton Station.
Along the sea-cliffs north of Thornton Station fossils are fairly
abundant. Some of the strata exposed, just above the base of
the cliffs, are almost entirely composed of small gasteropods and
pelecypods. These localities have previously been referred to as
the ‘‘upper gasteropod zone’’. The most peculiar feature of this
faunal horizon is that ninety per cent or more of the species found
here are also found living. All of the twenty species collected
from this horizon by the writer were recognized as belonging to
the Recent fauna. On the evidence obtained from the percent-
age of living species Ralph Arnold has referred this upper Mer-
ced to the Pleistocene age, while the greater portion of the
Merced, stratigraphically underlying it, has been placed in the
preceding period. From the faunal relations there seems to be
little doubt that Arnold’s determination is approximately cor-
rect. The close resemblance between the Recent fauna and that
of the upper Merced seems to suggest the possibility of there
being a break between the upper and the lower Merced which
can not be accounted for merely by the depositional record.

The stratigraphie evidence that appears to suggest an uncon-
formity in the Merced in the vicinity of Thornton Station has
already been given on a preceding page. In addition to this we
might add the faunal evidence in support of the unconformity.
A short distance south of Thornton Station Scutella interlineata
Stimpson, an extinet form, occurs abundantly. To the north of
the station the fauna is almost entirely Recent. The space sepa-
rating the two localities is hardly more than one quarter of a
mile. The apparent break in the two faunas could be explained
by having a space without a fauna, the deposition being con-
tinuous and the faunas changing by migration and extinction.
The apparent discordance in the strata could be explained either
by landslide or a fault as well as by unconformity. The evi-

1916] Martin: Pliocene of Middle and Northern Caltfornia 229

dence is therefore not sufficient to establish a stratigraphic break
at this locality. Z

The following fossils were collected by the writer from the
Merced Series at its type locality. The terms upper and lower are
used in connection with the fauna for correlation purposes. The
lower Merced ineludes that portion of the series which occurs
stratigraphically below the large landslide at Thorton Station.
The upper Merced is that portion occurring above the landslide:

List oF FossILs FROM THE LOWER MERCED

Echinodermata Gasteropoda
Scutella interlineata Stimpson Amphissa, sp.
Scutella, n. sp.? Astyris richthofeni Gabb
Pelecypoda Bittium asperum Gabb
Arca trilineata Conrad Calyptraea radians Lamarck
Cardium meekianum Gabb Calyptraea filosa Gabb
Cardium quadrigenarium Conrad Chrysodomus portolaensis (7?)
Chione succincta Valence. Arnold
Cryptomya californica Conrad Chrysodomus stantoni Arnold
Macoma inquinata Deshayes Chrysodomus tabulatus Baird, var.
Macoma nasuta Conrad colmaensis Martin
Marcia gibbosus Gabb Crepidula grandis Midd.
Modiolus rectus Conrad Crepidula onyx Sby.
Mya japonica Jay Crepidula princeps Conrad
Nucula suprastriata Carpenter Drillia inermis Hinds
Pandora grandis Dall Drillia mercedensis Martin
Paphia staleyi Conrad Neverita, sp.
Paphia staminea Conrad Nassa moraniana Martin
Paphia staminea, var. diversa Nassa mendica Gould
Sowerby Natica clausa Brod. & Sby.
Paphia tenerrima Carpenter Olivella biplicata Sb’.
Pecten, sp. Olivella pedroana Conrad
Phacoides annulatus Reeve Pachypoma, sp.
Saxidomus giganteus Deshayes Pisania fortis Carpenter
Schizothaerus nuttalli Conrad Pisania fortis, var. angulata Arnold
Schizothaerus pajaroanus Conrad Thais lamellosa Gmelin
Siliqua nuttalli Conrad Thais lamellosa, var. septentrionalis
Solen sicarius Gould Reeve
Spisula albaria Conrad Thais lima Martyn
Spisula catilliformis Conrad Tritonium, sp.
Tellina bodegensis Hinds Cirripedia
Zirphaea gabbii Tryon Balanus, sp.

The following list was obtained from the upper Merced north
of Thornton Station:

Echinodermata Paphia staminea Conrad
Echinarachnius excentricus Esch. Saxidomus nuttalli Conrad
Transennella tantilla Gould
Pelecypoda
Cardium corbis Martyn Gasteropoda
Cryptomya californica Conrad Acanthina engonatum Conrad
Macoma inquinata Deshayes Astyris californica Gaskoin
Macoma nasuta Conrad Astyris gausapata, var. carinada
Mytilus edulis Linn. Reeve

Ostrea lurida Carpenter Cerithidae californica Hald.

230 Unversity of California Publications in Geology [Vor. 9

Gasteropoda (continued) Nassa mendica, var. cooperi Forbes
Drillia inermis Hinds Natica clausa Brod. & Sby.
Lacuna compacta Carpenter Olivella biplicata Sby.

Nassa fossata Gould Thais lima Martyn

Nassa mendica Gould

MERCED OF BOLINAS BAY

A very limited area of Merced occurs immediately west of
the entrance to Bolinas Bay, about twenty miles northwest of
the type section at Seven Mile Beach. Along the cliffs south of
the town of Bolinas the basal beds rest unconformably upon
much disturbed strata of middle Miocene age. As at the type
locality, the beds have been folded into a large monocline dip-
ping eastward at an angle of approximately twenty degrees. The
strike is north twenty to twenty-five degrees west. In litho-
logical character the formation very closely resembles the series
at Seven Mile Beach. Gray and light-brown fine-grained sand-
stones predominate, with a very small amount of clay and fine
conglomerate. No accurate measurement of the thickness was
attempted, but taking into consideration the small angle at which
the beds dip and the limited area over which they occur, a con-
servative estimate would hardly place the thickness beyond five
hundred feet.

A collection of fossil marine invertebrates made principally
from the base of the section at Bolinas has revealed the occur-
rence of the following species:

Echinodermata Gasteropoda
Scutella interlineata Stimpson Astyris richthofeni Gabb
Pelecypoda Drillia mercedensis Martin
Cardium meekianum Gabb Epitonium indianorum Carpenter
Macoma inquinata Deshayes Nassa moraniana Martin
Macoma nasuta Conrad Nassa mendica Gould
Modiolus rectus Conrad Natica clausa Brod. & Sby.
Paphia tenerrima Carpenter Olivella biplicata Sby.
Schizothaerus nuttalli Conrad Olivella intorta Carpenter
Spisula catilliformis Conrad Thais lamellosa Gmelin

Spisula hemphilli Dall

All of these species, including the most characteristic, occur
in the Merced Series at the type locality and show the close con-
nection between the two sections.

MERCED OF ANO NUEVO BAY

An area, similar to that at Bolinas Bay, occurs along the
east shore of Ano “Nuevo Bay, about fifty miles south of the

1916] = =Martin: Pliocene of Middle and Northern California 231

Golden Gate. This area although very limited is of importance
as it shows the relations between the Merced and the under-
lying Purisima. The two formations at this locality are con-
formable. The strata of both dip slightly toward the northeast,
the strike being north and northwest. The beds consist of soft
rusty-yellow and brownish-gray medium-grained sandstone with very
small amounts of gravel and clay. In the upper horizon the soft
material is interstratified with numerous hard calcareous layers
which are abundantly fossiliferous. In the underlying Purisima
the fossils are imbedded in concretions instead of in the ecaleareous
layers as in the Merced. This is the most noticeable lithological
difference between the two horizons, the greater portion of the
sediments being similar in texture and color in the two sets of beds.

The following fossils, which were collected from the Merced
horizon at Ano Nuevo Bay, show the close connection with the
beds at Seven Mile Beach:

Pelecypoda Bathytoma carpenteriana Gabb

Acila castrensis Hinds Chrysodomus stantoni Arnold
Arca trilineata Conrad Crepidula grandis Midd.
Cardium meekianum Gabb Crepidula princeps Conrad
Cryptomya californica Conrad Drillia mercedensis Martin
Macoma nasuta Conrad Epitonium indianorum Carpenter
Marcia oregonensis Conrad Margarita pupilla Gould
Modiolus rectus Conrad Nassa moraniana Martin
Panomya ampla Dall Nassa mendica Gould
Panope generosa Gould Neverita, sp.
Paphia staleyi Gabb Olivella biplicata Sby.
Paphia tenerrima Carpenter Olivella intorta Carpenter
Solen sicarius Gould Olivella pedroana Conrad
Schizothaerus pajaroanus Conrad Cirripedia

Gasteropoda Balanus, sp.

Astyris richthofeni Gabb

MERCED OF PILLAR POINT

Another important outcrop of Merced oceurs at Pillar Point
in the extreme northwest corner of the Santa Cruz Quadrangle.
Here the beds consist of dark-brown shale interbedded with coarse
brown and gray medium-grained sandstone. The strata are tilted
at various angles and show the results of considerable distortion.
These beds appear to be connected, beneath the bay, with those
exposed along the shore near the mouth of Purisima Creek. The
lithological similarity suggests stratigraphic connection. The strati-
graphic position of these beds suggests the possibility that they were
at one time connected with the beds at Seven Mile Beach. If such

232 University of California Publications in Geology [Vor. 9

relations could be established definitely, it would aid materially in
showing the close connection between the Merced Series and the
Purisima Formation south of Halfmoon Bay.

The following species have been obtained from the Merced at
Pillar Point:

Pelecypoda Spisula albaria Conrad
Macoma, sp. Spisula hemphilli Dall
Pecten oweni Arnold Gasteropoda
Phacoides annulatus Reeve Astyris richthofeni Gabb
Siliqua nuttalli Conrad Thais lamellosa Gmelin

The presence of Pecten oweni Arnold in this fauna points
toward a very close correlation between these beds and the Puri-
sima Formation a few miles farther south. It would also indicate
that they were slightly older than the beds at Seven Mile Beach,
since Pecten owen has not been found in that section. However,
the absence of this form from closely related beds can hardly be
taken as proof of a later age. It is the opinion of the writer that
lateral distribution is an important factor in explaining the absence
of such forms from certain formations. The character of the sea
bottom, the geographic position of the basin of deposition, and
numerous other factors might have been unfavorable for the main-

tenance of such characteristic species.

MERCED OF THE SARGENT OIL FIELD

In Santa Clara County, west and southwest of Sargent Station,
there is an important occurrence of marine sediments, which con-
tains a fauna similar to the upper Purisima and Merced formations
along the coast. This formation has been called Merced and
Purisima by Mr. William FI. Jones in his account of the geology
of this field. In the following discussion it will be referred to
as the Merced for the reason that there are beds beneath which
contain a number of species common to the lower Purisima which
are not common to the Merced. It seems advisable therefore to
use the name Merced in discussion of these beds.

The Merced of this region covers a number of separate areas, on
both sides of the Pajaro River, and extending to the southeast for
several miles. In some of these areas the structure is monoclinal,
the strata dipping toward the east, while in others it is synclinal,
as in the case of the large area one mile west of Sargent Station.

1916] = Martin: Pliocene of Middle and Northern California 233

In all of the localities visited by the writer, these beds appeared to
overlie conformably a formation which is closely related, faunally,
to the Etechegoin of the Coalinga district, but which was ealled
San Pablo by Jones.
page, it was pointed out that an unconformity had been reported
by Jones between the Mereed and this underlying San Pablo.
The most careful observations made by the writer have not given

In reviewing the literature, on a previous

us any evidence of a lithologic change between the beds referred to
the San Pablo and the beds referred to the Merced, nor was any
evidence of a stratigraphic break seen. The strata are composed of
gray and brownish-gray, medium-grained sandstones with some clays
and occasional seams of gravel.

The fauna from the upper horizon contains a number of forms
common to the Etchegoin as well as to the Purisima and Merced
formations. The percentage of living forms, however, is as great
as in the Merced at Seven Mile Beach, and ten per cent greater
than in the Purisima south of Halfmoon Bay. We are justified
therefore, in correlating these beds with the Merced at the type
locality.

The following species have been collected from the Merced of
the Sargent Oil Field:

Pelecypoda
Acila castrensis Hinds
Area canalis Conrad
Arca trilineata Conrad
Cardium meekianum Gabb
Cryptomya ovalis Conrad
Cryptomya quadrata Arnold
Dosinia ponderosa Gray
Macoma nasuta Conrad
Mactra coalingensis Arnold
Marcia oregonensis Conrad
Modiolus rectus Conrad
Mytilus coalingensis Arnold
Pandora (Clidophora) punctata

Conrad

Panope generosa Gould
Paphia staleyi Gabb
Paphia staminea Conrad
Paphia tenerrima Carpenter
Schizothaerus nuttalli Conrad
Schizothaerus pajaroanus Conrad
Siliqua nuttalli Conrad
Solen sicarius Gould
Spisula albaria Conrad

Spisula faleata Gould

Spisula voyi Gabb

Semele rubropicta Dall
Transennella californica Arnold

Gasteropoda

Astyris richthofeni Gabb
Bittium asperum Gabb
Calyptraea filosa Gabb
Cancellaria tritonidea Gabb
Drillia mercedensis Martin
Littorina scutulata Gould
Neverita, sp.

Nassa moraniana Martin
Nassa mendica Gould
Natica clausa Brod. & Sby.
Neverita recluziana Petit
Olivella biplicata Sby.
Olivella pedroana Conrad
Thais canaliculata Ducl.
Thais lamellosa Gmelin
Thais saxicola Valenciennes

Cirripedia

Balanus, sp.

MERCED OF THE SANTA ROSA VALLEY
The general stratigraphic, lithologic, and faunal relations of
the Merced of the Santa Rosa Valley have been outlined in review-

234 University of Califorma Publications in Geology [Vor. 9

ing the paper of Vance C. Osmont, who published the account of
the geology of that region. The locality has not been visited by
the writer and no additional evidence can be given. However the
fauna known from these beds is sufficient to warrant its correla-
tion with the Merced.

WILDCAT SERIES

PHYSICAL FEATURES

The Wildcat Series is typically represented in the south central
part of Humboldt County, California, in the form of a monocline
on the north slopes of Bear River Ridge, extending from the ocean
eastward to Bryan’s Rest. The strike of the strata is more or less
parallel with the general course of Eel River, i. e., west or north-
west. The beds are inclined toward the north at angles varying
between fifteen and forty degrees. In a few cases the inclination
is as great as seventy-five degrees, but these cases are rare, and
dips greater than forty degrees are uncommon. A short excursion
into the hills four miles northeast of Fortuna revealed the occur-
rence of marine sediments corresponding in age to the Wildcat
Series. The rugged topography common throughout the region is
characteristic of this formation and suggests that the territory cov-
ered by these beds is quite extensive. Later work may prove the
occurrence of this series over a much greater portion of Humboldt
County than it is now known to cover.

Beach Section—As with the Merced Series, the beach section is
most accessible and affords the best opportunity for study. At the
mouth of Oil Creek, one mile north of Cape Fortunas, the basal
beds, composed of rusty-yellow, shaly-structured, fine-grained sand-
stone, overlie a massive, coarse-grained, steel-gray sandstone which
has been greatly fractured and folded. The latter is probably not
later than Cretaceous and may possibly be Jurassic. Approxi-
mately half a mile farther north the rusty-yellow sandstone grades
rather suddenly into gray and blue-gray argillaceous sandstone
and clay. The material is soft and not well stratified, resembling
very closely the lithological characters of the Merced. This gray
and blue-gray sandstone with some variations continues north-
ward to Centerville, where it dips beneath a brown beach sand and
gravel lying in nearly horizontal position. The strike for the whole

1916] = Martin: Pliocene of Middle and Northern California 235

section is approximately due west. The dip varies from thirty
degrees at the base to fifteen degrees at the top of the section.

Ferndale Section—Another excellent section for study was
found along the Wildeat road which connects Ferndale with
Capetown. On the north side of Bear River Ridge, about six and
three-quarter miles south of Ferndale, the basal beds of the Wild-
cat Series were again found overlying the Mesozoic rocks, which
form an important part of Bear River Ridge. In the lower por-
tion of the section the series consist of rusty-vellow and_ light-
brown shales which closely resemble some of the shale members
of the Monterey Series in Contra Costa County. The shale gradu-
ally grades into a fine-grained sandstone still retaining the shaly
structure. The thickness of these lower beds can hardly be more
than six or seven hundred feet. No bedding planes are visible, so
that the attitude of the strata and the thickness can not be meas-
ured accurately. The overlying strata have a dip of twenty to
twenty-five degrees north. It is probable that these lower beds
have approximately the same attitude. Overlying the basal beds
is a gray, argillaceous, fine-grained sandstone which has a well-
developed shaly structure. This member is probably of consider-
able thickness, as it outcrops along the roadside for several
miles, and near the top, where the altitude was taken, the strike was
found to be N 75° W, with a dip of twenty degrees to the
north. Four and one-quarter miles south of Ferndale this mem-
ber grades into a light-brown sandstone, which in turn grades
into a massive gray sandstone. The latter is in the neighborhood
of fifteen hundred feet in thickness, and on account of its mas-
siveness is the most conspicuous member of the entire series.
Three distinct beds of conglomerate outcrop above the massive
eray sandstone, each being separated by fifty or more feet of
coarse sandstone. The combined thickness of the conglomerate
ean hardly be less than two hundred feet. At the top of the
exposed section brown sand and gravel overlie the conglomerate,
which appears to dip beneath the Eel River Valley. °*

Alton Section.—A section along the west bank of the Eel River.
from Metropolitan to Alton, gave approximately the same results
as the Ferndale section. Along the south bank of Kel River, south
of Metropolitan, the beds consist of gray and rusty-yellow, fine-
grained sandstone and clay. On following Howe Creek south
toward its source, brown and reddish-brown shale was encount-

236 University of California Publications in Geology [Vor. 9

ered. In going north along the west bank of Eel River a con-
siderable thickness of gray sandstone stained brown and greenish
brown is met with. Farther north, at the mouth of Price Creek,
a massive gray sandstone occurs. In lithologic character and
thickness this member resembles very closely the massive gray
member found in the upper portion of the Ferndale section. The
uppermost strata of this section, along the west bank, have been
removed by the river in forming the terrace on which the town
of Grizzly Bluff is now situated. Fortunately, however, it is con-
tinued along the east bank north of Alton. Here the conglomer-
ate outerops and continues north toward Rohnerville. The top
of the section, as at Ferndale, is composed of brown sand and
gravel.

Scotia Section On the west bank of Eel River, near the mouth
of Monument Creek, the Mesozoic rocks outcrop in a large mass
just above the wagon road. The strike of this formation is due
west with a south dip of seventy degrees. A short distance to
the north a reddish-brown shale is exposed, having a strike of
N 70° KE, and dipping to the north at an angle of forty-five degrees.
In continuing north the shale gradually changes to a lighter color
and to a more sandy character. The strike also changes N 70° W.
Several localities gave the same results and it seems probable
that the attitude taken in the reddish-brown shale was measured
in strata that had been slightly dislocated.

West of Seotia the light-brown shaly material is replaced by
a massive light-brown sandstone. This member continues north
for several hundred feet, where it gradually grades into brown
shale and finally into a blue-gray argillaceous sandstone and clay.
Beyond this point the section is not continued along the west
side of the river, but is most remarkably exposed along the east
side. Here the blue-gray sandstone and clay are followed by a
brown and greenish-gray sandstone which contains a fauna some-
what similar to that found near the top of the upper Neocene
at the mouth of Bear River, and also in the Alton section at a
corresponding horizon. Blue and gray sandstones of considerable
thickness are found next above the brown and_ greenish-gray
material. In general, this member is composed of soft strata, but
in some localities it has sufficient stability to form almost perpen-
dicular cliffs three or four hundred feet in height. These cliffs
are often referred to as the Scotia Bluffs. In this portion of the

1916] = Martin: Pliocene of Middle and Northern California 237

section fossils are extremely abundant, often occurring in solid
beds a foot or more in thickness. Beyond the Scotia Bluffs the
beds enter a rugged and heavily timbered region where they could
not be traced with accuracy. They undoubtedly extend northward
to the Van Duzen River, where the uppermost part of the series
should be found.

Shively Section—Alonge the railroad track, one and_ one-half
miles southeast of Shively, a very excellent section of strata was
encountered. The base of the section, which is near the base of
the series, consists of reddish-brown shale and light-brown shaly
sandstone. The brown shale is overlaid by a blue-gray shale which
grades into a coarse-grained gray sandstone. The latter is very
fossiliferous and forms a prominent bluff on the north side of Eel
River just below Bryan’s Rest. The strike of the strata at this
locality is N 75° W. The dip is toward the northeast at an angle of
fifty degrees. One mile north of Shively the same horizon oceurs
as a prominent bluff on the east side of the river opposite the small
town of Pepperwood. Here the strike is N 40° W, with a small
east dip.

All of the sections here described have a close similarity with
respect to the larger lthological divisions. We find in each case
a similar sequence of beds. The lower portion in each section
consists of rusty-yellow shales with light-brown and gray shaly
sandstones. Overlying this is a series of gray and blue-gray sand-
stones with some clay shales. Toward the top the sandstone becomes
coarse-grained and often conglomeratic. It is evident, therefore,
from these sections that the Wildcat Series can be divided into two
divisions on a lithologic basis—a lower member consisting of brown
and rusty-yellow shales, followed by brownish-gray sandstone, and an
upper member consisting of gray and blue-gray sandstone, with some
clay shales and well cemented layers of sandstone, followed by coarse
sandstone and conglomerate in some sections. In the Scotia section
the division between the two members occurs about three-quarters of
a mile north of the railroad station at Scotia. In the Alton section
the division occurs on the south bank of the Kel River south of
Metropolitan.

FAUNA OF THE WILDCAT SERIES

Taken as a whole, the Wildeat Series is one of the most fossil-
iferous Tertiary formations known along the coast of California.

238 University of California Publications in Geology [Vor. 9

Near the middle of the beach section, one-half mile north of the
mouth of Guthrie Creek, several very good fossil localities are
to be found. From this horizon as many as thirty species, prin-
cipally small gasteropods, were obtained. The bluffs opposite Rio
Dell contain the most abundant fauna of any locality that the
writer has so far encountered. Some of the strata, a foot or
more in thickness, are composed almost entirely of fossil inverte-
brates. Over fifty pounds of perfect specimens were collected
in a part of one day from the central part of the section one mile
north of Scotia.

One of the most noticeable characters of the fauna from the
Wildcat Series is the division which can be made between the
upper and lower portions, which agrees very closely with the
lithologic divisions. The lower portion contains some species which
are common to the Empire Formation of Coos Bay and other Mio-
cene formations along the coast of California and Oregon. The
upper portion contains a fauna quite similar to that of the Merced
Series, and is very conspicuously boreal in character. The upper
part of the lower division contains Pecten dillert Dall, Argobuc-
cinum arnoldt Martin, Chrysodomus lawsont Martin, and numerous
other species which are not found in the beds above. On the other
hand, the upper division contains a large number of species which
do not occur below. There is a distinct break in the fauna corre-
sponding to the two lithologic divisions. If this series were to be
divided between the Miocene and the Phocene the separation would
probably come between the two divisions that are indicated by the
lithology and the fauna.

The following species were obtained by the writer from the
lower division of the Wildcat Series:

Pelecypoda Gasteropoda
Glycimeris, sp. Argobuccinum arnoldi Martin
Macoma calcarea Gmelin. Argobuccinum scotiaensis Martin
Macoma nasuta Conrad Chrysodomus andersoni Martin
Pecten dilleri Dall Chrysodomus lawsoni Martin
Pecten propatulus Conrad Chrysodomus scotiaensis Martin
Solemya ventricosa Conrad Chrysodomus eurekaensis Martin
Thyasira barbarensis Dall Liomesus sulculatus Dall
Thyasira bisecta Conrad Margarita condoni Dall
Yoldia striagata Dall Solariella peromabilis Carpenter

Turris perversa Gabb
Turris cammani Dall

The following list of species were obtained from the upper
division of the Wildcat Series:

1916] Martin: Pliocene of Middle and Northern California 239

Echinodermata
Scutella interlineata Stimpson
Scutella, n. sp.?

Pelecypoda
Acila castrensis Hinds
Acila conradi Meek
Cardium coosensis Dall
Cardium meekianum Gabb
Chione securis Shumard
Cryptomya ovalis Conrad
Kennerlia, sp.
Leda taphria Dall
Lyonsia californica Conrad
Macoma ¢alcarea Gemlin
Macoma, n. sp.
Macoma secta Conrad
Macoma yoldiaformis Carpenter
Marcia oregonensis Conrad
Modilus stalderi Martin
Mya japonica Jay
Nucula suprastriata Carpenter
Pandora grandis Dall
Panomya ampla Dall
Paphia staleyi Gabb
Paphia staminea Conrad
Pecten caurinus Gould
Phacoides annulatus Reeve
Schizothaerus nuttalli Conrad
Schizothaerus pajaroanus Conrad
Siliqua lucida Conrad
Siliqua nuttalli Conrad
Solen sicarius Gould
Spisula albaria Conrad
Spisula catilliformis Conrad
Spisula voyi Gabb
Tellina bodegensis Hinds

Thracia trapezoidea Conrad

Venericardia castor Dall

Venericardia subtenta Conrad

Venericardia subtenta, var. quad-
rata Conrad

Yoldia striagata Dall

Gasteropoda

Admete dilleri Martin

Argobuccinum oregonensis Redfield

Astyris richthofeni Gabb

Bela, sp.

Bela santae-monicae Arnold

Bittium filosum Gould

Boreotrophon fleenerensis Martin

Chrysodomus altispira Gabb

Chrysodomus andersoni Martin

Chrysodomus halibrectus Dall

Chrysodomus liratus Martyn var.

Chrysodomus rectirostris Carpen-
ter, n. var.

Chrysodomus tabulatus Baird

Drillia fleenerensis Martin

Drillia inermis Hinds

Drillia mercedensis Martin

Epitonium indianorum Carpenter

Mangilia cf. tabulatus Carpenter

Natica clausa Brod. & Sby.

Natica, near lewisii Gould

Neverita recluziana Petit

Olivella pedroana Conrad

Taranis strongi Arnold

Thais lamellosa Gmelin

Tritonofusus halli Dall

Trophon muriciformis Dall

Turris perversa Gabb

Nearly all of the forms included in the list from the lower
horizon of the Wildcat Series, excepting the new species, occur in
the Miocene of Coos Bay and other Miocene localities along the
coast. It is probable, therefore, that the lower portion of the
Wildeat Series is not later than the uppermost Miocene.

A large number of the species included in the list from the
upper horizon have not previously been reported from this series.
The list contains species that have been collected from all of the
sections described on previous pages. A number of those obtained
from the upper portion of the beach section, north of Guthrie
Creek, occur commonly in the Pliocene of Santa Barbara and in
the Pleistocene of San Pedro. This points toward a rather late
Pliocene age for the uppermost portion of the beach section. The
Seotia Bluffs, north of Scotia, yielded a fauna very similar to the
Merced Series south of San Francisco, a fact which warrants a
very close correlation between the two groups of beds.

240 University of California Publications in Geology [Von 9

Uprer MIocENE or BEAR RIVER

At the mouth of Bear River, Miocene and possibly Pliocene
beds are to be found in the form of a synelinal fold. The sec-
tion along the beach across this syneline extends for a mile on
either side of the mouth of the river. On the north side of this
area the basal beds rest unconformably upon a shaly portion of
the Mesozoic formation which forms the headlands at Cape Fort-
unas and Cape Mendocino. These beds extend southward to
within one mile of Cape Mendocino, where the basal portion is
again found in contact with the Mesozoic rocks. The strata at
this point dip northeast at an angle of thirty-five degrees. The
strike is N 60° W. On the north side of the syneline the strike
of the beds is N 50° W, and the dip is to the south at an angle of
seventy degrees. The middle or axis of the syneline lies about
half a mile south of the mouth of the river. The area covered
by this formation extends only a short distance up the stream,
and from a number of strikes and dips taken on either side of the
river it appears to be a erescent-shaped area representing the
extreme end of a syncline. In the lower portion the beds consist
of fine-grained sandstones and shales which have buff and brown-
ish-gray colors. Near the top of the section the strata consist of
eray sandstone with thin layers of clay interstratified with it.

The determination of this formation as Miocene was made
upon the finding of Pecten peckhami Gabb, and sharks’ teeth in a
small guleh a few hundred yards north of the mouth of Bear
River. A small collection of fossils made from the upper horizon
contained a number of species which are common to the Empire
Formation on Coos Bay.

The following species were obtained from the upper portion
of the upper Miocene formation at the mouth of Bear River:

Echinodermata Venericardia castor Dall
Schizaster stalderi Weaver Gasteropoda

Pelecypoda Argobuccinum arnoldi Martin
Chione, sp. Chrysodomus bairdi Dall
Macoma calearea Gmelin Liomesus sulculatus Dall
Panope estrellana Conrad Tritonofusus saundersi Martin
Phacoides acutilineata Conrad Turris cammani Dall
Solemya ventricosa Conrad Volutopsius eurekaensis Martin

All of these species, excepting those listed as new forms, occur
in the Empire Formation of the Oregon coast and it seems prob-
able that the two formations were approximately contempo-
raneous in deposition.

1916] = Martin: Pliocene of Middle and Northern California 241

Six miles east of Capetown, at the mouth of the south fork of
Bear River, a small area of Miocene beds outcrops. These beds
extend across the river to the north side where a small area is
exposed. They consist of brown and gray sandstone. A few
poorly preserved fossils were obtained, among them a species of
Pecten, Glycymeris conradi Dall, and Venericardia castor Dall. It
is probable that this small area was at one time connected with
the beds at the mouth of Bear River.

Purisima FORMATION

Physical Features—The rocks of the Purisima Formation occupy
two geographically separate areas within the Santa Cruz Quad-
rangle, one on either side of the Santa Cruz Mountains. The one
of greater importance occupies an area triangular in shape stretch-
ing from Halfmoon Bay southward along the coast to the mouth
of Peseadero Creek, and then inward along Pescadero Creek to
its source. The northeastern boundary of the area extends from
the town of Halfmoon Bay southeast, more or less parallel to the
main divide, to the mouth of Oil Creek. From this point the
southern boundary follows Pescadero Creek northwest to Jones
Gulch, where it turns due west for several miles, then turning
southwest toward the town of Pescadero. The narrow strip
extending south to Ano Nuevo Bay is limited on the east by a
prominent fault scarp along which movement took place, letting
the Purisima down against the Monterey shale. On the west it
is limited by outerops of the Chico Formation on which the
Purisima les unconformably.

The area of Purisima thus outlined has been folded into a
syncline whose axis he approximately in the middle, extending
southeast and northwest, conforming to the general structure of
the region. The northeast wing of the syncline flanks the west
slope of the Santa Cruz Range from Halfmoon Bay to Oil Creek,
overlying probably unconformably Monterey shale, Vaqueros sand-
stone, and Tertiary diabase. The general strike is N 40° W, and
the strata dip toward the southwest at an angle of twenty degrees.
The southwest wing of the syncline has been distorted by fault-
ing and has been partly submerged by the transgression of the
sea. The beds dip to the north and northwest at low angles,
usually not more than ten or twenty degrees. In some localities

242 University of California Publications in Geology [Vor. 9

the Purisima appears to rest conformably upon the Monterey
shale and to grade into it; in other localities a marked litho-
logical change marks the contact between the two formations.

The Purisina Formation is composed chiefly of sandstone.
Whitish diatomaceous shales occur in some localities but they are
relatively of small extent. The formation as deseribed by Arnold
and Haehl can be separated into three lithologic divisions: a
lower sandstone, a middle shale, and an upper sandstone. The
lower sandstone occurs most prominently along Pescadero Creek
east of Jones Gulch and in the vicinity of La Honda. Here it
attains a thickness of nearly three thousand feet. Conglomerate
and coarse-grained sandstone occur at the base immediately over-
lying the Monterey shale. The upper portion of the lower mem-
ber consists of soft gray and brown sandstones, occasionally grad-
ing into clay. The shale member extends over a wide area south
and east of San Gregorio. Its thickness in this locality reaches
approximately three thousand feet. In some respects it re-
sembles the shales of the Monterey Series, varying from the pure
diatomaceous shale to the impure clay shale. The upper sand-
stone covers an area approximately four miles in width extending
along the coast from Halfmoon Bay to Pescadero Creek. It con-
sists of light gray and brownish-gray fine-grained sandstone, usu-
ally soft and friable. Occasionally clay shale is interstratified
with the fine-grained sandstone. The thickness of the Purisima
Formation, as measured along Purisima Creek by Ralph Arnold,
was approximately eight hundred feet.

The Purisima occurring on the east side of the Santa Cruz Moun-
tains, southwest of Stanford University, consists of soft quartzose
sandstone. Near the base of the section, which is hardly more than
three hundred feet in thickness, the beds contain numerous barnacles
(Balanus concavus Bronn). The lime from the barnacles has greatly
hardened the sandstone, according to Arnold and Haehl, who de-
scribed this series. The fauna from these beds appears to represent
a lower horizon than the Purisima along the west side of the Santa
Cruz Range.

Fauna.—tThe Purisima Formation is not extremely fossiliferous,
although a few localities have afforded a large number of species.
The middle and lower members have yielded only a few species that
are determinable, and these are forms which have a comparatively
long life-period.

1916] = Martin: Pliocene of Middle and Northern California 243

The following species were obtained from the upper standstone
member of the Purisima Formation, chiefly from the sea-cliffs south
of Halfmoon Bay:

Echinodermata Solen sicarius Gould
Echinarachnius gibbsii Rémond Spisula albaria Conrad
Scutella interlineata Stimpson Spisula ecatilliformis Conrad
Scutella perrini Weaver Spisula hemphilli Dall

Pelecypoda Thracia trapezoidea Conrad
Acila castrensis Hinds Yoldia cooperi Gabb
Acila rectus Conrad Zirphaea gabbi Tryon
Arca canalis Conrad Gasteropoda
Arca trilineata Conrad Argobuccinum oregonensis Redfield
Cardium meekianum Gabb Astyris richthofeni Gabb
Clidiophora punctata Conrad Bathytoma carpenteriana Gabb
Cryptomya californica Conrad Bittium asperum Gabb
Cryptomya ovalis Conrad Calyptraea filosa Gabb
Dosinia ponderosa Gray Calyptraea inornata Gabb
Leda taphria Dall Chrysodomus liratus Martyn
Macoma calcarea Gmelin Chrysodomus portolaensis Arnold
Macoma inquinata Deshayes Chrysodomus purisimaensis Martin
Macoma nasuta Conrad Chrysodomus stantoni Arnold
Marcia oregonensis Conrad Chrysodomus tabulatus Baird
Panomya ampla Dall Crepidula, cf. onyx Sby.
Panope generosa Gould Crepidula prineeps Conrad
Paphia staleyi Gabb Drillia mercedensis Martin
Paphia tenerrima Carpenter Miopleiona oregonensis Dall
Pecten healeyi Arnold Nassa moraniana Martin
Pecten nutteri Arnold Nassa mendica Gould
Pecten oweni Arnold Natica lewisii Gould
Pecten purisimaensis Arnold Natica clausa Brod. & Sby.
Phacoides annulatus Reeve Thais lamellosa Gmelin
Schizothaerus nuttalli Conrad Cirripedia
Schizothaerus pajaroanus Conrad Balanus, sp.

Siliqua nuttalli Conrad

This list contains a few forms, such as Pecten healeyr Arnold,
and Pecten purisimaensis Arnold, which are supposed to be charac-
teristic of the Pliocene, and have not so far been reported from the
Merced Series at the type locality. This, together with the fact that
certain supposedly Miocene forms, Pecten oweni Arnold, Pecten nut-
teri Arnold, and Echinarachnius gibbsii Rémond, occurred in this
formation, was the basis upon which Arnold and Haehl separated
these beds from the Merced Series and applied the new name Purisima
Formation. The presence of a number of the larger pectens has
caused some palaeontologists to place the beds as intermediate be-
tween the Pliocene and Miocene, and still others to place them entirely
within the Miocene. It is a well-recognnized fact that the division
between the Miocene and Pliocene in California is not well marked
in any of the formations, and any separation attempted, outside of
that suggested by the faunas, is more or less arbitrary. It is not the
object of this paper to make an accurate age determination, but

244 Unwersity of California Publications in Geology [Vor. 9

rather to show the relations between the various formations consid-
ered. It is the opinion of the writer that the Purisima Formation is
the equivalent of a part of the Etchegoin and the lower portion of the
Merced Series at Seven Mile Beach.

ETCHEGOIN OF THE SAarGent O11 Frevp

Unconformably overlying the Monterey shales of the Sargent Oil
Field there is a formation composed of conglomerates, coarse and
fine-grained sandstones, and shales which was correlated by William
F. Jones with the San Pablo Formation of the Mount Diablo region.
The basis on which the correlation was made was the occurrence of
viviantitic sandstone. Jones separated this member into five lithologic
divisions; A, the lowest member, consisted of conglomerate and
coarse brown sandstone; B and C were composed of gradational series
of light azure blue sandstones, quite coarse at the base and grading
into shale at the top; D consisted of fine and medium-grained sand-
stone; E, the uppermost of the series, consisted of coarse and brown
sandstones. <All of these members are conformable and belong to one
formation. The separation was doubtless made to bring out more
strongly the hthological variation within the formation.

The territory covered by these beds comprises several small
areas a short distance west and northwest of Sargent Station. The
largest of these areas have been folded into an anticline and a syn-
cline. The axes of these folds extend from the southwest toward
the northeast. Both are parallel to La Brea Creek, one on either
side, the anticline on the north and the syneline on the south. These
beds grade upward into the Merced horizon which conformably
overlies them.

Fauna—tThe correlation of these beds with the San Pablo Forma-
tion was made by Jones upon a lithologie similarity, the occurrence
of the vivanitie sandstone. Recent collecting in this horizon has
brought out some rather interesting faunal relations. The San
Pablo of this region has a very close faunal relationship to the
Etchegoin of the Coalinga district, very much closer than with the
San Pablo at the type locality. This is shown in two ways: (1) Of
the forty species obtained from the San Pablo in the Sargent Oil
Field nearly all occur in the Etchegoin while only sixteen occur in
the San Pablo near Mount Diablo, and these have a very wide
vertical and horizontal range; (2) The species that are most char-

1916] Martin: Pliocene of Middle and Northern California 245

acteristic of the Etchegoin, such as Echinarachnius gibbsii Rémond,
Pecten wattsui Arnold, and Pecten nutterr Arnold, occur in the
Sargent section and do not occur in the region of Mount Diablo. It
seems, therefore, that we are justified in assigning the beds pre-
viously known as San Pablo, in the Sargent Oil Field, to the Etche-
goin Formation.

\

The following species were collected by the writer from the
Etchegoin of the Sargent Oil Field:

Echinodermata Pecten wattsi Arnold
Echinarachnius gibbsii Rémond Pecten watts*, var. etchegoini An-
Pelecypoda derson.
Arca trilineata Conrad Phacoides annulatus Reeve
Cardium meekianum Gabb Saxidomus nuttalli Conrad
Chione securis Shumard Schizothaerus nuttalli Conrad
Cryptomya quadrata Arnold Schizothaerus pajaroanus Conrad
Glycimeris coalingensis Arnold Siliqua nuttalli Conrad
Macoma indentata Carpenter Solen sicarius Gould
Macoma inquinata Deshayes Spisula albaria Conrad
Macoma nasuta Conrad TiraciasesD:
Macoma secta Conrad Yoldia cooperi Gabb
Mya japonica Jay Zirphaea gabbi Tryon
Mytilus coalingensis Arnold Gasteropoda
Ostrea atwoodi Gabb Calyptraea filosa Gabb
Panomya ampla Dall Chrysodomus portolaensis Arnold
Panope generosa Gould Crepidula princeps Conrad
Paphia staleyi Gabb Nassa fossata Gould
Paphia staminea Conrad Natica, n. sp.
Paphia staminea, var. orbella Car- Natica recluziana Petit
penter Thais kettlemanensis Arnold
Pecten nutteri Arnold Cirripedia
Pecten oweni Arnold Balanus, sp.

Later NEOCENE AND QUARTERNARY DEposits OF CAPE BLANCO, OREGON

At Cape Blanco, Oregon, about fifty miles north of the California
boundary, there are marine sediments which are closely related to
the later Phocene formations of the California coast. In order to
point out these relations the geology and palaeontology of this
region will be briefly outlined.

The formations concerned in the geology of this locality inelude
the Myrtle Formation, the Empire Formation, the Elk River Beds,
and a terrace formation which may be later than the Elk River Beds.
The oldest rocks are those of the Myrtle Formation, considered by
Diller, who described the formation, to be of Cretaceous age. Strata
of this formation outcrop along the cliffs from Cape Blanco north-
ward to Blacklock Point. They also occupy a very small area imme-
diately south of the Cape. Farther inland the Myrtle Formation is

246 University of California Publications in Geology [Vou. 9

of widespread occurrence. The Empire Formation, of middle Mio-
cene age, unconformably overlies the Myrtle Formation. The rocks
of this series occupy two separate areas. The strata of one of these
areas outcrop along the ocean cliffs from Cape Blanco to a small
gulch one and one-half miles southeast, where they are unconform-
ably overlaid by later deposits. The other area outcrops along the
cliffs north of Blacklock Point to Floras Lake. Diller in mapping
this region considered that the Empire Formation extended contin-
uously from Cape Blanco to the mouth of Elk River, a distance of
two and one-half miles. This was an error, as will be shown later by
palaeontological evidence. The strata of this area dip with a uni-
form inclination from Cape Blanco southeast to the small gulch
already referred to. The lower members are composed of a yellow-
ish-gray sandstone. Above this there is a layer of tuff which is about
twenty feet in thickness. This tuff contains numerous leaf impres-
sions. The upper portion consists of whitish and yellow sandstone,
medium to fine-grained. <A collection of fossils from these beds
warrants their correlation with the Empire Formation of Coos Bay.
Diller designated this formation as the Cape Blanco Beds.

Immediately north of the small gulch, one and one-half miles
southeast of Cape Blanco, the uppermost strata of the Cape Blanco
Beds are unconformably overlain by a thick bed of conglomerate
which grades upward into a coarse brown sandstone, and finally
into blue-gray argillaceous sandstone. South of this gulch the cliffs
afford a complete section to the mouth of Elk River. The beds
exposed in this section can be separated lithologically into two
divisions: (1) a blue-gray argillaceous sandstone or mudstone which
is the same member as was found overlying the conglomerate on the
north side of the gulch; (2) a loose gray sand which is very similar
to the sand of the Upper San Pedro Series at San Pedro, California.
These two members extend the entire length of the section from the
gulch to the mouth of Elk River, where they dip beneath the beach
sand. The blue-gray argillaceous sandstone forms the base of the
cliffs for the entire distance. The loose gray sand overlies it con-
formably, both dipping at a very small angle to the south and east.
The difference between these two members is most noticeable in the
face of the cliff. The lower beds are consolidated and form a vertical
wall twenty or thirty feet in height. The overlying loose sand yields
easily to weathering and as a result a distinct angulation occurs in
the face of the cliff at this point.

1916] = Martin: Pliocene of Middle and Northern California 247

Near the mouth of Elk River both of these horizons are very
fossiliferous. In the lower beds the fossils occur in numerous hard
concretions, while in the overlying sands they occur in a thick mass
as an unconsolidated shell bed. The faunas are sufficiently distinct
to allow the series to be separated into two horizons, although they
are not separated by a stratigraphic break. From the great number
of Recent species found in the upper horizon it seems certain that
it is very closely related to the Upper San Pedro Series, at San
Pedro, and is at least Pleistocene in age. The underlying beds also
contain a large number of Recent forms, but they likewise contain
a large number of species that are common to the Merced and the
Wildeat Series, and it is not improbable that this lower horizon rep-
resents very late Phocene and is to be correlated with the upper-
most part of the Wildeat Series.

Along the summit of the cliff one quarter of a mile southeast of
Cape Blanco there is a formation of gray sand, mudstone, and gravel
lying horizontally across the tilted edges of the Empire Formation.
At the base of this deposit there is a fossil bed containing fifteen or
twenty species, all of which appear to be Recent. A number of these
are species of clams which bury themselves in the mud, such as
Schizothaerus nuttall’ Conrad. These fossils are, at the present
time, imbedded in the uppermost part of the Empire Beds instead of
the more recent deposit. This formation is hardly more than ten or
fifteen feet in thickness and is overlain by three or four feet of soil.
Diller considered these beds to be a part of the Pleistocene deposits
at the mouth of Elk River, the Elk River Beds. There are a few
species in each of these localities which are not common to both.
The difference in the faunas may be due to the difference in position
with regard to the strand line. The formation at the top of the eliff
near Cape Blanco was undoubtedly deposited after the coastal plain
had been formed, and just previous to its uprising. It is probable
that the major part of the Elk River Beds were deposited during
the period in which the coastal plain was forming, and in this way the
beds at the mouth of Elk River would antedate the formation uncon-
formably overlying the Empire Formation near Cape Blanco.

CORRELATION

The physical features of the formations, with which we are deal-
ing, have been briefly outlined, and complete faunal lists from all of

248 University of California Publications in Geology [Vor. 9

them have been brought together, we therefore are in a position to
sum up the evidence and work out the faunal relations which exist
among all of these formations. In general there are two methods
on which faunal correlations are based: (1) the use of character-
istic species; (2) the percentage method. The latter may include
the percentage of species common among the formations themselves
as well as the percentage of living species common to the formations.
In the present work it seems advisable to use all the methods avail-
able in order to obtain as nearly perfect results as possible.

In applying the percentage method a system of tables has been
constructed which shows in numerical values the approximate rela-
tion among the formation or portions of formations. The first
table (table 1), shows the occurrence of all of the species that were
obtained from all of the formations which have been considered in
this investigation. Table 2 shows in numerical values the number of
living species found in each formation, and also the number of
species common to all of the formations among themselves. To
show this in tabulated form, all of the formations are arranged as
ordinates and also as abscissae. The square space opposite any two
of these formations, which are arranged normal to each other, con-
tains the number of species common to both of those formations. It
is evident that the number of species from the different formations
varies considerably, and since this is the case the magnitude of the
number itself can not be taken as a direct index of the relation
between the formations. The percentage of species common to
the formations compared will not vary directly as the number of
species. Table 3 has been constructed to show this percentage and
also the percentage of living species common to the formations. There
are two percentages to be taken into consideration; the percentage of
the species in A that is common to B, and the percentage of the species
in B that is common to A. It is certain that these percentages will
usually be different, since there is, In most cases, a greater number
of species in one formation than in the other. For our purpose in
correlating, these percentages can be added and used as a factor.
The magnitude of this factor will indicate the approximate relation
between any two formations: that is, if the combined percentages of
the species common to A and B is greater than the combined per-
centages of the species common to B and C, it will indicate that A
and B are more closely related than B and C.

There are a few sources of error which will affect the results

1916] Martin: Pliocene of Middle and Northern California 249

very greatly unless they are eliminated. A small number of species
from one formation will change the factors considerably. It is
necessary therefore to have a large number of species from all of
the formations which are to be considered. Geographical separation
also affects the results very noticeably. Formations that are widely
separated will have a smaller number of species in common than
formations that are not so situated.

With our data tabulated as in the following tables, and with
the possibility of errors in mind, we ean readily construct a
correlation table which will show the relations of each formation as
worked out by the percentage method. Turning to table 3 we find
in the first column, reading from top to bottom, the percentage of
living forms. The formation having the greater per cent of living
species will, of course, be the most recent. Those having the same
percentage of living forms will be approximately contemporaneous
in deposition. Considering then the percentage of living species we
find that the upper Merced is very recent, certainly Pleistocene.
The Merced of Bolinas Bay, of Ano Nuevo Bay, of Seven Mile Beach,
of Pillar Point, and of Sargent Oil Field are all of the same age and
are very closely related to the upper Wildeat and to the Purisima.
The Etchegoin of the Sargent Oil Field, the lower Wildeat, and the
so called Miocene of Bear River are older.

Taking now the factors representing the percentage of species
common to the formation among themselves, we find that a similar
relation will work out. Comparing the formations to the upper
Wildeat we find that the largest factors correspond to the Merced
of Seven Mile Beach and to the Merced of Sargent Oil Field. If we
compare the formations to the Etchegoin of the Sargent Oil Field
we find that the Purisima is more closely related to it than the Mer-
ced or the Wildeat Series. By eomparing each of the formations in
this manner a relation would be worked out which would agree very
closely with that shown in the column of the percentages of living
species.

In correlating by means of the most characteristic species we
find that the Etchegoin of the Sargent Oil Field contains a number
of the short-lived forms which occur abundantly in the Etchegoin of
the Coalinga district. We are justified, therefore, in correlating
these formations and assigning them to the same horizon. <A few of
the short-range species of the Etchegoin fauna occur commonly in
the Purisima, and it seems probable that a portion of the Purisima

250 University of California Publications in Geology [Vor. 9

is equivalent to a portion of the Etchegoin, and cannot be distinctly
separated from it as suggested by Dr. J. P. Smith. Whether the
whole Purisima Formation is equivalent to the Etchegoin cannot at
present be definitely settled, because the fauna of the lower Purisima
is rather meager and is not sufficiently characteristic.

The Mereed Series, the upper portion of the Purisima, and the
upper Wildcat contain a number of short-lived species in common and
it is evident that they are approximately equivalent. The Merced
Series and the upper Wildeat are certainly contemporaneous, and
the lower portions of these two formations are not far removed from
the uppermost Purisima.

The lower Wildcat and the so-called ‘‘Miocene of Bear River”’
have a few species in common which are not found above these hori-
zons. They also contain species which occur abundantly in the
Empire Formation of Coos Bay. From this evidence it seems prob-
able that the lower Wildeat and the ‘‘Miocene of Bear River’’ belong
to a lower horizon than the typical Merced and follow the Empire
Formation very closely in the order of deposition.

From the superposition of beds similar in age it is probable
that the lower Wildcat and the ‘‘Miocene of Bear River’’ are closely
related to the Etchegoin and a portion of the Purisima Formation.

Transmitted June 16, 191}.

a

5

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a

Martin: Pliocene of Middle and Northern California

1916]

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[VoL. 9

University of California Publications in Geology

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Martin: Pliocene of Middle and Northern California
x xX X

1916]

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Biggs Sa eta ‘IdQD Byelijseidns eynonN
SiS eeep rise ceiag ag ae RE a ‘UUTT SI[Npe SATIVA

[ VoL. 9

University of California Publications in Geology

SUIAV'T

pooreyy, todd)

quod LV[[L_ “Peo

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Martin: Pliocene of Middle and Northern California

1916]

x : aa
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Seg ais ete icseb oc ahs a led snjoo1qiyey snwoposAiyO

University of California Publications in Geology

256

SUIAVT

fe

peor9yy todd

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(panuyuog) I ATAVL

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snulopossélyO
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i

f Middle and Northern California

Pliocene o

Martin

1916]

Sa FG ERNE Tao es ee [eA BlOOLXes
prin gad eee ee oe eae UAB], CULT
“QAI SITVPUOLI}UAIdIS ‘IVA ‘BSOT[AWIP]
etapa nant amasa conta cag UI[OW) BSO[[OWPT
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sTeUL
STeUL
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in aR Ear gene eee ploury Isuo1js STUBIBL
Sie cuba aa aia JojuedieD SI[Iqewmoied e[[al1elog
a plouly eJe[Nsue “IVA SIVIOJ BluUeSsIg
catia a aaa aaah ai kere ‘IdQ SIq10J eluURSsSIg
Peng eiaese oo arto aerate pe1u0gj evuvorIped PI[PATIO
ag i eas pe ec rite “IdQ 8110} UL BI[AATIO
agen man ny ‘AqS eyedTTdIq BITPATIO
gr aera Wed VURIZN[IGI (VYIOAON) BOTTeN
Sai be a pet ia ae P[Noyy TIStMa] 1v9U ‘BOTJeN
Barip ace es eee “AGS XY ‘porg esneypo voneN
ceaaenanmaas SoqIOy I1edo0od ‘1vA ‘BOIPUDTA BSSBNY
a pase ee a oh tani pInoy wvoIpusetw essen
See eager st eae sae eo ee a ‘ds ‘u ‘essen
bie ache cae ae ‘PPI PPLIN, (eIqsUINQ) xen]
Boone gae paeragt ee Ile@d Sisusuo0sel1o BUuOorTe[doly
Sic alien oc Naar pinoy eiIdnd eases ieyy
Sa gama eg ae leq tuopuood eiaesiey
BRB UAA GES a cent Nar SsSS SARS ETALATS ‘1dQ e7e[NgGe} ‘Jo ‘BI[ISULI
ep aan prea ay cea PInoy eyelNyNos BUTIOINT
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SS aa da aha dae orcciaociy Il@d snje[no[ns snsoeurloryz
Sacinaa nia guaaeia Tine a JojJuediep) eyoeduio0d euNnoe'T
Set taa ea aaa “IdQ WNAIOURIPUL (BTVOS) WntIU0OIdG”

University of California Publications in Geology [VoL. 9

258

SUIAI'T

peoseyy todd

WO CI[L_q ‘pe.Loyl

Aeg OACNN OU ‘peteyy

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yuasaieg ‘poso1eyy

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QVOPILA\ OAT

(4) 9UBDOTT TOATY LVI

peluonD vluvso1s VULOSOTWIRL
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VIdadIUalg

ade aaa aa UAV SISUsvYoIne snisdoyNpoOA
progres aerps led fuewwers stn
ener Saga aamaus ecided Ss eas qqey esioArJod ST1Iny
ae ey alpen Le led stwa0jlommwu woydoLy,
Bee apg pia Le eR ae ‘ds ‘umntuoql.y,
ULV, SISUSVUNJAOJ SNSNJOUOPLLL

yas care weg AY led W[ey snsnjouoyLy
ae aie apace oe ane a ips ame eae a ag a ‘ds ‘steUh

x

(panuijuog) VdodoraLsvp

quosaieg ‘u1oseqoyy

(panuiuog) I ATaVL

1916] = =Martin: Pliocene of Middle and Northern California

TABLE 2

CORRELATION TABLE OF THE PLIOCENE FORMATIONS OF MIDDLE
CALIFORNIA!»

a
ars:
A P
cansee

EYE A Vgl T'S ees eee sees oe eee eee ceca ee
Uipper? Merced: 22 220 2k
Merced, Bolinas Bay.................... 15 6 19
By
1a als
7 14
0 8
3. (8
6 14
5 64
fea |
Bear River Miocene (?)................ 1 0 0
TABLE 3
a
= &
a

LV AT eee ee Scie ee ats

Upper Merced ..............00.022222222222--- pe

Merced, Bolinas Bay..... do
Merced Ano Nuevo Bay 39 104
Lower Merced, Type Locality... 50 70 112
Merced Sargent Oil Field.......... 59 48 106
Merced, Pillar Point-................. 47 0 54
Upper Waldcat. 272-2... 59 18 54
Purisima Formation ................... 47 37 97
HEtchegoin, Sargent ...................... 44 3 31
Mower Wildcat 220.22 9 9 10
Bear River Miocene (?) .............. 0 0 0

Merced, Ano Nuevo Bay

Merced, Ano Nuevo Bay

Lower Merced, Type Locality

Lower Merced, Type Locality

Merced, Sargent Oil Field

Merced, Sargent Oil Field

Merced, Pillar Point

oo }

oo w A

Merced, Pillar Point

19 See description of Table 2 and Table 3 on page 248.

3

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e a 8
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Be Ry GaSe
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66...
Dba OU Nees
aly ey el aes
43 120
By Se sl 53

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S @ 3
= es
eS
Ss 2 2 &
a q a S
> 3 = &
=) Ay | H
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26 20 7 ....
31 21 11 70

Bear River Miocene (?)

11

Bear River Miocene (2?)

sew ee

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= AE Br ee

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. ee ee ea Cee ee ee a... eee

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PRR MUA YE css. Moahehs, vie» artcletenefate

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ee eC see ee wee

jornicus, by Loye Holmes Miller. .
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TMD Mae ss np an xin sowie Adhere: 9| ohaselewere s| Metanatate io) shalt et eta hops teat ae meae oid eure cia
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2 Glandler ...: .j... | iw ee 8 ihone otal h peleueite’ aloes Ye =. oflokatees aia (teem Seine
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the Material from the Pacific Voast, by Asa C. Chandler..... 4
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fornia, By Barl (Lerdy Packard lay ..'..ohiere ne ae ee eee er at

i 13. Vertebrate Fauna of the Cedar Mountain Miocene in Western Nevada, hk
ay. 5 Ma, Wiperieun 3.1 52..\.).. + sch ss chi dep pepe e Deir emacs 02 cae an a

nA 14, Pauna from the Lower Pliocene of Jacalitos Creek and Waltham Caiion, iy
“eS OF; (ee brea NE ae m0" hi Seen Sram + pate a oie Sle, eos ety rete ‘nip fot Re iets vie Blais! aia
2A 15. The Pliocene of Middle and Northern California, by Bruce Martin.....-:
he 16. Notes on the Cenozoic actrinae ‘of the Pacific Coast of North America, by
4 Leroy Packard (ey Pence eee e eee e ete ee erence nntereere eee sete eeeee
"d

¢

re

RS Se OE a FSF ns 3

,

Ae at vt oy

Issued May 1, 1916

_ OF THE PACIFIC COAST OF
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i / j BY j
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i

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e 4 3

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 9, No. 15, pp. 261-360, pls. 12-35 Issued May 1, 1916

MESOZOIC AND CENOZOIC MACTRINAE
OF THE PACIFIC COAST OF NORTH AMERICA

BY

EARL L. PACKARD

CONTENTS

PAGE
VETAU ETS COKE Oy eer cee ear pk Se Ry ort 2 dee re nc Oe 262
. 263
. 265
Variations of the Elements of the Mactrine Shell... 267
EWS COT Vg O be te) Wa CURIA Cece c ees cc cee ce soccer cae nose nee san eee cede oe cee eee See secre cee covecureeeessocueene 273

The Geologic and Geographic Range of the Pacific Coast Mactrinae—
TIES) OVER tro PRR Ss eNO oe a aR 1 neo A ee 274
Phylogeny of the Pacific Coast Mactrinae 276
WOTIGIUS TONG erent ee ere etree, ES et Mee cee, 2 ener 277
Systematic Description ‘of the Mactrine Species. 277
plperntamully Mactraceal Gray: 2c. -ccce-cteck een ae nc ccc eee cece 277
amily. Wactridae Gray 22...2...ccc-.ccccceccccececceces-cecccccecesaccacsecassccseneccpece-cesns-eanseeeee 277
SUN HTN GY ee ebay ys) DEW) eee ee ee ee 278
Genus Wactra, Winmaeus sec... e2 ee. cc cde ccenseecesc ce oop cenee eee ecee eeeeeeceossecee 278
Subgenus Mactrotomla, Dall) 2 ccc.ccce cece eos cece cee ceee sees ere reeecees ec ceee 278
Section Mactrotoma Dall —....20..22220200.....2222eeeieeeeeeeeneeeeeee eee centres 278
EV C GH ive TS Ue Cr OU Casas oe sete ere gee eee ee 278
SKereualoval Sybeokoneateeirey reps), TDF W bse eae ee 279
Mactra dolabriformis (Conrad) —......2222.-2-200000022 eee 279
Syeveuioyot WW hicretopaaleein es) ID EU) ee ca i eee eee 279
Mactramcalifonmica: Comma dics ii.2 ose esc cece oce -cteneesee wane noes sceceeseeee-e 280
Subgenus Mactrella Gray. —..+.20.2.2..222222-22.c---ceencenneeeeescoeeee cece eeeeeeeeeeeeeeeeee 281
Mia GUase OTOu aT Gays cscs soe cece cnte= coe cec aes cee bone de ccoeescoccesgeesessesiee 281
Mactra trampasensis, N. SDP. -02......222222.222222eeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee 282
GemUSiiS pisuil as Gir aya es oerec oe ces coe eee Se ere oe occ truee toes eee tec ste 283
Subgenus Hemimactra Swainson. ..............2222-2-.-20:0-ceeeeceeeeeeeeeeeeeeeeee-- 283
SECOLONe Mat Ome TTS eI) ally esse eee oe eens eee eee ee essen oes 283
UStay Viva CGD) eee cece cence eee een ane ee eee 283
SHonishanley, Cofy ill witowes valbitshs (Oxoy als ete Kol Sees eer nee eee eee eee 285

Spisula mercedensis, MN. SD. ---22---.-----2--2e---2ceeeeeeeeeeeenneneeeeeeeeeeeeeeceee 286

262 University of California Publications in Geology [Vou. 9

!

PAGE
Spisula hemphillii (Dall) 222222 ee 287
Spisula occidentalis (Gabb) -..222..2.0..22-c.220cc22ccecccceeeecceeeceeeeeeeeeeee-e 288
Spisula abscissa (Gabb) 2222.2. =e ee 289
Spisula) albaria (Conrad): 2 ee 290
Spisula albaria (Conrad) var. ramonensis, n. var. .......--- 291
Spisula selbyensis, nm: SD. (2-2 ee 292
Spisula plamulata (Comrad) -.....:x.-c200occ- cccecteececee 293
Spisula merriami Packard _o..2.....0..22.cceeecceeeeceeeeceeceeeeeeeeeeeeeeeee- 294
Spisula acutirostrata, mn. SD). eee 295
Spisula brevirostrata, nm. Sp. ----.2cccccccccecccceeceeeesceeee-s 296
Subgenus Symmorphomactra Dall ......2..c2eeccccceceeceeeeeeeceeeeeeeeeeeeee 297
Spisula falcata (Gould) 2222... 297
Subgenus. Cymbophora Gab). -...---1..----------2-0----20e0-0eeeeeoeee--e-cs see 298
Spisula ashburnerii (Gabb) -..--0..-22.....----eeececceceeceeeeeeeeeceeeeeeeeeeeee 298
Spisula gabbiana (Anderson) 2...2220....22000002200-eeeeee eee eee eee 299
Spisula chicoensis, New Name ou... ee eee eee eee eevee eee 300
Subgeneric Position Uncertain 200..0.0.000..2.222cccceeeeeeeeeecceeeceeececeeeeeeeeeee 301
Spisula callistaeformis Dall 2.2202202.20occeeecceecceeeeeeeeeeeeeeeeeeeee 301
Spisula coalingensis (Arnold) .20.22.2..220002.222.cceeeceeeeeeeeeeeeeeeeeeeeee es 301
Spisula lenticularis (Gabb) 20.....22222... 0c eeee cess eee eee eeeee eee 302
Spisula sisquocensis Arnold —...222222...2cteeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee, 302
Spisula’ tejomensis, 1, “SPs, lcccecesccccees sss cece cece eceeses sscessessten eens 303
Genus Mulinia Gray
Mulinia:denSata Comrad 22... lees reese cee eee eee
Mulinia densata Conrad var. minor Arnold
Mrurlimiaralitar i OWiCavie te iiss ceesnsa eee seeeee sneer eee essen eee
Mulinia undilifera (Weaver) ........22..2...22.::cccc-seecccecceeeeceeeeeeeneeeeee
Mralinia, Vanidiesi iC Wieaivier)) cecsccee cease ceee cee eeeeeeeseeeeeeeeee esha
AW Gul balaie ye vorel oN KGYSS OVENS idly {310m ceeeeeeeee se eee ere err a
Generic Position sWmicertaim) so setscccccscrere cere reac ene eccee ee ee reeeen ee ee
MactraC?) eibbsamay Week sree eiecccccc cece seccaeeceeee=ncaseeceeeseees eee
Mactra(?) montereyana Arnold ..........0....2.22222-----------
Mactra(?) stanton Axmold) 220... 20 csc cee eee ceeee
Mactra.(?)) tenuissima, Gabb) 22222222 eee ceee eer
SpisulaiG?)s weavert: Pacha) 22izkccccccecccesssecee- 22a. -0e-sec sess ee eee
Species Not Valid
Mactra(?) -zablotensis, Comma) —o22.22ccccce cece 2 eee canee cence sees eee 313
INTRODUCTION

Although a considerable number of species belonging to the sub-
family Mactrinae have been described from the Pacific Coast region
of North America, the taxonomy and the phylogeny of the group
have been but imperfectly understood. The existing situation is due
largely to great individual variation in the superficial specific char-
acters of the shell. As a consequence of our lack of understanding
of the group, there has been much confusion regarding the geologic
range of certain mactrine species.

1916] Packard: Mesozoic and Cenozoic Mactrinae 263

It is the purpose of this paper to apply the taxonomic system
proposed by Dr. W. H. Dall to the West Coast mactrine species, to
record the known variation found within each species of this sub-
family, to discuss the geologic and geographic ranges of the different
species, to determine the value of each species to the stratigraphic
geologist, and incidentally to describe several forms that are appar-
ently new to science.

The term Pacific Coast region as used above is intended to include
only the territory from Mexico northward to the coast of Alaska,
and extending eastward to the Sierra Nevada and the Cascade
mountains.

A large number of fossil and living Mactrinae belonging to the
University of California and the University of Washington have
been available for study. These collections include several types of
species and varieties.

The writer wishes to express his thanks to Dr. John C. Merriam
for the general supervision of this paper; and to Dr. Charles E.
Weaver of the University of Washington, who loaned several type
specimens and gave much valuable assistance during the early stages
of this study.

HISTORICAL SKETCH

During the period in which the West Coast species were described
the basis of classification of the Peleeypoda changed considerably.
Gray? in his study of the Mactridae, in 1837, differed from his
predecessors in that he based his classification largely upon the posi-
tion of the ligament, whereas the earlier naturalists had considered
the general shape, the pallial line, or some minor anatomical character
as having the largest taxonomic value. Gray’s system, modified by
such workers as Reeve2, Conrad, and Gabb, was in general use until
Dall? in 1889 demonstrated the value of the pelecypod hinge as a
basis of classification. Subsequent investigators have accepted Dall’s
conclusions and have successfully applied his methods in the separa-
tion of the subordinate groups of the Pelecypoda.

1 See Deshayes, G. P., Traite elementaire de conchyliologie, tom. 1, pt. 2,
p. 256, et seq., 1843-1850.

2 Reeve, L. A., Conchologia Iconica, “Monograph of the Genus Mactra,”
vol. 8, 21 pls., April 1, 1854.

3 Dall, W. H., On the hinge of the Pelecypoda and its development, etc.,
Amer. Jour. Sci. (3), vol. 38, pp. 445-462, 1889.

264 University of California Publications in Geology [Von. 9

The first mactrine species reported from the Pacific Coast region
of North America was Mactra californica’, described by Conrad in
1837 from Santa Barbara, California. Other species were subse-
quently described by the same author in various papers, the last of
which appeared in 1867; his list of species is completed by the fol-
lowing: Mactra albaria, M. catilliformis, M. diegoana, M. planulata,
Mactra(?) gabiotensis, Mulinia densata and Spisula dolabriformis.
Conrad® also contributed in 1867 a synopsis of the Mactridae in
which he designated a typical species for each of his taxonomic
eroups. Gray in the latter part of 1837 defined the superfamily
Mactracea, the family Mactridae and several genera as now recog-
nized. Among his new species a West Coast form appears under
the name of Mactra exoleta.

During 1848-50 Gould described Mactra falcata and M. nasuta,
and Meek reported in 1861 the new species, M. gibbsana, which he
obtained in a boulder of doubtful Cretaceous age, from the Straits
of Juan de Fuca. Rémond described a Mulinia in 1863 under the
name Cardium gabbui, which later became the type of Gabb’s genus
Pseudocardium.

Gabb described in 1869 the genus Cymbophora, the typical species
of which he had previously named Mactra ashburneru. His new
mactrine species include: Callista voyi, Hemimactra lenticularis,
Hemimactra (2) occidentalis, Lutraria truncata, Mactra ashburnern,
Mactra (2) tenuissima and Schizodesma abscissa.

The eastern species Mactra warrenana Meek was reported by
Whiteaves from the Cretaceous of the San Juan Islands, Washing-
ton, but later it was referred by the same author to one of Gabb’s
West Coast forms.

Dr. W. H. Dall made the next contribution to the knowledge
of the West Coast Mactridae, when in 1894 he published a synopsis
of both the East and West Coast species®. This was amplified during
the following year’, and again later in the Transactions of the

4 References to the original descriptions of the species mentioned in this
section may be found under the headings of the species in question in the
systematic portion of this paper.

5 Conrad, T. A., Catalogue of the Family Mactridae, Amer. Jour. Conch.,
vol. 3, appendix, pp. 30-47, 1868.

6 Dall, W. H., Synopsis of the Mactridae of northwest America, south to
Panama, Nautilus, vol. 8, pp. 25-28, and pp. 39-48, 1894. ;

7 Dall, W. H., Synopsis of a review of the genera of Recent and Tertiary
Mactridae and Mesodesmatidae, Proc. Mal. Soc. London, vol. 1, pp. 203-213,
1895.

1916] Packard: Mesozoic and Cenozoic Mactrinae 265

Wagner Free Institute of Science’. These last two papers contain
excellent definitions of the genera, subgenera and sections into which
the family had been divided previously. The many cuts of the last
paper showing the important taxonomie characters of the different
groups add much to the usefulness of the paper. Between the years
1894 and 1909, Dall described the following: Mactra hemphillii,
Mulinia oregonensis, Spisula alaskana, S. callistaeformis and NS.
precursor.

In the meantime F. M. Anderson described Mactra gabbiana,
and Dr. Ralph Arnold added the following: Mactra coalingensis,
M. montereyana, M. stanton, Mulinia densata var. minor, Spisula
catiliformis var. alcatrazensis and S. sisquocensis.

Dr. C. E. Weaver in 1912 reported the following from the
Miocene of Washington: Pseudocardium landesi, P. gabbi var. altum,
P. gabbi var. elongatum, P. gabbi var. robustum and P. gabbi var.
undultferum.

BASIS OF CLASSIFICATION

Certain shell characters that are now considered of taxonomic
value were omitted in the early descriptions of the West Coast Mac-
trinae, because systematists did not regard them as of importance.
The shell characters such as general shape, or position of the umbones,
which were considered by these earlier writers are now known to be
too variable to be of much value to the systematist. A number of Con-
rad’s mactrine species were based upon specimens too immature for
specific determination. This was recognized by Carpenter, who in
speaking of Conrad’s early descriptions, says: ‘‘Conrad’s types being
lost, and his species imperfectly described from very young specimens,
a difficulty attends their identification.’’®

In reviewing the mactrine species it has been found necessary to
apply a standard to each described form. <A study of the specific
variations within this subfamily has revealed the fact that the most
constant shell characters within a species are those dependent upon
the dentition. Dall was the first to recognize the value of the hinge
of the Mactridae as a satisfactory basis of classification. He provided
a special nomenclature for the hinge dentition of these forms in his

8 Dall, W. H., Mactridae, Transactions Wagner Inst. Sci., vol. 38, pt. 4,

pp. 862-891, 1898.
9 Carpenter, P. P., Brit. Assn. Rept. 1863, p. 99.

266 University of California Publications in Geology [Vor. 9

articles upon this family published in the Proceedings of the
Malacological Society of London,’® and in the Transactions of the
Wagner Free Institute of Science.“

The mactroid hinge consists of a /\-shaped cardinal tooth, situ-
ated just anterior to the resilifer, and an anterior and a posterior
lateral in the left valve, which fit between two laterals, or laminae,
in the right valve. The cardinal of the left valve is formed of two
parts, an anterior and a posterior arm. These arise from the hinge
plate and are fused along a dorsal median line. The posterior
arm often supports, at its base, a secondary process, which
may overhang the pit or chondophore, and may extend parallel to
the arm of the cardinal to a height equal to that of the cardinal
itself. This accessory lamella is strongly developed in the lutrarine
species Schizothaerus nuttallu (Conrad). This may be clearly seen
in the figure of that species found on plate 35. Other lamellae occur
upon the laterals of certain species, notably upon those of Mactra
californica. The cardinal of the right valve differs considerably
from that of the left. The more diverging arms of this tooth fit
outside those of the left cardinal of the opposite valve. In the
right cardinal the arms are often unequally developed. In the case
of those species belonging to the subgenus Cymbophora the posterior
arm is entirely absent, while other subgenera are characterized by
having the cardinal arms of nearly equal development. Mactra
exoleta is a good example of such a form. Furthermore the
cardinal arms are seldom united along a median line as is the case
in the left valve, but are slightly separated and joined to the dorsal
margin of the shell.

The resilium and the ligament bear a varied relation to each
other and serve, therefore, as important bases for generic definitions.
In the genus Mactra the two are separated by a shelly ridge which
extends ventrally from the beak. This fragile partition is but im-
perfectly seen in many of the typical mactroid species. It is repre-
sented in the left valve of Mactra exoleta by a low ridge extending
from a point under the beaks to the ventral-posterior margin of the
resilifer. A condition that is somewhat comparable is seen in the
lutrarine species Schizothacrus nuttallii. In the genus Spisula the
resilium and the ligament are not separated by any limiting wall

10 Dall, W. H., Proc. Mal. Soc. London, vol. 1, pp. 203-213, 1895.
11 Dall, W. H., Trans. Wagner Institute Sci., vol. 3, pt. 4, pp 862-891, 1898.

1916] Packard: Mesozoic and Cenozoic Mactrinae 267

of shell. In Mulinia the union of these elements is even more inti-
mate, since they are completely submerged in a single well-defined
pit.

In all of these genera there is a process known as the spur,
which arises from the dorsal shell margin just posterior to the
. cardinal, and extends out over the chondophore. In the mactroid
species this is often fused to the partitioning ridge above mentioned
in such a way as to separate the ligament distinctly from the
resilifer. In other cases the spur coalesces with the dorsal margin
of the shell, forming a roof over the upper end of the pit for the
resilium.

Three areas adjacent to the cardinals have been named by Dall’?
the anterior, the posterior and the ventral sinuses. The anterior
sinus is situated between the anterior arm of the cardinal and the
dorsal margin of the shell. The posterior one bears a similar relation
to the posterior arm. The area between the cardinal arms and the
ventral margin of the hinge plate is known as the ventral sinus.

VARIATIONS OF THE ELEMENTS OF THE MACTRINE
SHELL

The various elements of the shell that might have a taxonomic
value would include: the general shape, the position of the beaks,
the type of the pallial line with its sinus, the muscle scars, and the
dental armature. The utility of these characters will depend upon
their specific constancy. It is therefore important for the purposes
of this paper to discuss each of these details of the mactrine shell.

The members of this subfamily are found to vary specifically
from an equivalve and nearly equilateral form such as Mactra
californica to the inequilateral species Spisula hemphillii, and from
the slightly convex form of the latter to that of the very ventricose
species Mactra exoleta. The outlines of the mactrine shell vary from
a trigonal to an elongate type, which may be illustrated respectively
by the species Spisula merriani and 8S. falcata. Of even more
immediate interest are those variations that occur within a single
species.

If a number of mactrine forms are studied, it is found that there
is a marked degree of variation of the general shape within the

12 Op. cit., p. 864.

268 University of California Publications in Geology [Vou. 9

limits of certain species; while others appear quite constant when
the same character is considered.

This form-variation is rendered comprehensible by graphic
methods. In figure 1 the abscissas represent the height and the
ordinates the length of the shell. A line connecting the two points
which correspond to these dimensions represents the ratio of the
length to that of the height of the shell. These measurements,
based upon a number of specimens, when plotted in this manner
show a series of lines in which deviation from parallelism indicates
the inconstancy of these ratios for the specimens under consideration.

The graphs show that Spisula selbyensis (fig. 1f) is the least
constant, and that Mactra californica (fig. 1c) is the most constant
of the mactrine species represented. The graphs of S. ashburnerii
(figs. ld, le) and S. merriami, show but little variation, suggesting
that they are readily separable upon the basis of their general shape.
Mulinia densata and S. selbyensis are among the more variable forms
shown.

The species represented that are shown to be the more variable,
are difficult of determination. Mulinia densata and Spisula selbyensts
are often confused with such forms as M. pabloensis and S. albania,
or even with other less closely related species. The variations in the
general shape of S. catilliformis, especially in the case of juvenile
specimens, include forms closely resembling Schizothaerus nuttalli.

Figure la shows the variations of Spisula catilliformis through
several geologic periods. This graph is based upon specimens from
different beds ranging in age from Lower San Pablo to and including
the Recent. Such studies suggest that as time advanced this species
became more constant as regards general shape. Specimens from
the Lower San Pablo show shape-variations greater than have been
observed in the living species. This, together with evidence shown
by the graphs of Mulinia densata (fig. 1b) and Spisula selbyensis
(fig. 1f), and still further augmented by a consideration of a number
of species not here plotted, suggests a remarkable inherent variability
of the Miocene species in contrast to those of earlier or later periods.
No adequate explanation of this has been found, unless it be that
this indicates a period of specific unstability due perhaps to adapta-
tions to the shifting local environments of the Miocene and to the
aggressiveness or capacity for variation often characterizing the
earlier stages in the life-history of a genus or other group.

269

Mesozoic and Cenozoic Mactrinae

Packard:

1916]

la, Spisula
Spisula ash-
1g, variation

Figs. la to 1g. Graphs showing ratios of lengths to heights:

catilliformis; 1b, Mulinia densata;

d,

il

le, Mactra californica;

s

1f, Spisula selbyensis ;

lbyensis.

burnerii; le, Schizothaerus nuttallii;

in the position o

se

S.

aks in

f the be

270 University of California Publications in Geology [Vot. 9

The charts give no definite clue to the relative variations
within genera, for each genus includes species of a great range of
variability. This inconstaney of form-variation is not confined to
the subfamily, since it is also evident in the lutrarine species
Schizothaerus nuttallii (fig. le).

If each of the specimens within the groups charted above had
not possessed characters that were constant for the given species,
it might be thought that measurements had been taken upon speci-
mens representing more than a single species. Not only did each
suite of shells have constant characters, but in every instance there
were gradational forms connecting the extremes within the group.

If it be granted that the conclusions, based upon the measure-
ments and other less precise methods given above, are legitimate,
it is manifest that for some species, at least, the general outline of
the shell is not a character of any considerable taxonomic value.
Although it serves admirably in some instances, it fails in many
others and therefore it cannot be employed as a specific criterion
that is equally applicable to all of the members of this subfamily.

The prominence of the beak and its position with reference to
the anterior extremity, have often been used as important specific
characters in the definitions of mactrine species. The relative
amount of shifting of the umbones within the limits of a single
species is shown in figure lg. In this graph the abscissas represent
the distance from the umbones to the anterior extremity, measured
along a line parallel to that of the greatest anterioposterior
diameter, and the ordinates represent the greatest length of the shell.
The same suite of specimens of Spisula selbyensis used in the previ-
ous instance was made the basis for these measurements. The
scarcity of parallel lines in this chart indicates the marked amount
of variation in the position of the beaks. Upon comparison with the
graph of length-height ratios of the same species (fig. 1f) it is found
that these ratios are more nearly constant than are those based
upon the relative position of the umbones. Similar conditions
occur in Mulinia densata, M. pabloensis, Spisula albaria and S.
abscissa.

The shape and the prominence of the umbones are noteworthy
variants within the limits of certain species such as Mulinia densata.
In the more ventricose Pseudocardium forms the beaks are very
prominent, in marked contrast to the small ones of the typical form.

1916] Packard: Mesozoic and Cenozoic Mactrinae 271

Gradational shapes connect the extremes of such a series. The tumid
specimens of this species also show considerable variation in the
juxtaposition of the umbones, ranging from a condition in which
they are closely approximate to that in which they are widely sepa-
rated in the two valves.

The pallial sinus is a conspicuous shell character and has often
been considered as having a certain classificatory value. As a means
of distinguishing Spisula catilliformis from the lutrarine species
Schizothaerus nuttallii the pallial sinus may be successfully em-
ployed; and it is, no doubt, likewise applicable in other instances,
especially if the comparisons are not made between closely related
species. Nevertheless, Dall’s'® conclusions regarding the pallial
sinus for the Pelecypoda in general will also apply to the sub-
division of this class to which the mactrine shell belongs. Since
the muscle sears are also of doubtful taxonomic value they need not
be discussed here.

Several different types of hinge plates are observable among the
Pacific Coast Mactrinae. <A broad, flat one, which is more or less
closely associated with an elongate form of shell, is seen in Spisula
catilliformis (see Plate 17), 8. voyi or S. falcata, while an extremely
narrow hinge plate is seen in Mactra exoleta or S. selbyensis. The
shape of the chondophore is modified to a certain extent by the
dynamic forces which determine the general form of the shell. The
elongate specimens of Mulinia densata or Schizothaerus nuttallu pos-
sess relatively shallower and broader resilifers than do the shorter in-
dividuals of the same species. This suggests a possible difficulty in
the way of using the hinge for the basis of classification. A similar
response to the changing shape of a species might be conceived as
applying to the entire dentition and thereby depreciating the value of
the taxonomic system advocated in this paper. In so far as there is
a variation in shape involving the dorsal portion of the shell, just so
far must there, of necessity, be an accommodation of the dental arma-
ture to these changing conditions. In the case of an anterioposterior
compression of a shell, as may be seen in the ventricose forms of
Mulinia densata, a corresponding crowding of the dental units is
inevitable; but regardless of this concentration of the elements there
still remain certain fundamental differences, for this crowding in-
volves all of the elements of the hinge in such a way that each tooth

13 Dall, W. H., Am. Jour. Sci. (3), vol. 38, p. 446, 1889.

272 University of California Publications in Geology [Von. 9

still retains its relative position with reference to that of the others.

Dall has shown that the mactrine cardinal tooth revolves, as
it were, upon an axis in such a manner that the cardinal arms
occupy different positions upon the hinge plate in the different
species. This apparent rotation is seen most clearly in the right
valve. Sprsula catilliformis and S. planulata serve as extreme ex-
amples of this condition. Although this shifting of the position of
the cardinal arms is noticeable when different groups are studied,
it is negligible when species are considered among themselves. In
certain forms there is a marked tendency for the arms of the left
cardinal to thicken in such a way as to form a massive triangular
block-tooth instead of the typical mactrine cardinal composed of two
distinct arms. This condition appears to be common in the heavy,
thick-shelled forms like Mulinia densata. A similar tendency is seen
in Mulinia alta, where a thickening of the cardinal arms occurs,
although the hinge teeth are much more delicate than in the form
just mentioned. The shorter specimens of Schizothaerus nuttallii
appear to have the same type of cardinals. This may be attributed
in part to senility, but not entirely so, for the younger specimens
show the same tendencies to a lesser degree. The relative height of
the cardinal is variable. It is perhaps less noticeably variable in
the mactroid species than in the spisuloid ones.

In discussing the laterals Dall’® writes: ‘‘the paired laminae are
more variable than the single ones’’. There is, then, a recognized
variation of the laterals as well as of the cardinals. This variation
may be expressed in terms of length, height and thickness of the
teeth. The lamella on the arm of the left cardinal is so fragile that
it is seldom seen on fossil specimens, and only occasionally in Recent
material. It is quite variable in most of the mactrine species, judg-
ing from the few specimens in which it has been seen and from its
known inconstancy in the indigenous lutrarine species.

The question now arises regarding the status of a proposed
classification based primarily upon a hinge which is as inconstant as
has been, indicated above. Dall’® says: ‘‘The distribution of the
parts of the hinge in a single species is remarkably uniform, but if
groups of species are considered, the types seem to gradually
approach and almost merge one in another.’’ After making this the

14 Dall, W. H., Trans. Wagner Inst. Sci., vol. 3, pt. 4, p. 869, 1898.
15 Op. cit., p. 868. 16 Op. cit., p. 867.

1916] Packard: Mesozoic and Cenozoic Mactrinae 273

basis of considerable study, the writer would agree with Dall regard-
ing the constancy of these relationships and he would further state
that this distribution of the elements of the hinge offers the most
reliable known basis for the classification of this family.

The greater constancy of the laterals as compared with the
laminae of the right valve, and the greater constancy of the form
of the left cardinal give the greater taxonomic value to the left
valve.

A study of the cardinal tooth of the left valve shows that in
different species it occupies various positions on the hinge plate;
from that at the dorsal margin of the plate, as in Mactra nasuta or
Spisula catilliformis, through a condition in which it is about cen-
trally located on the hinge plate, as in Mulinia densata, to that seen in
S. albaria or Mactra exoleta, in which the cardinal arises from the
ventral margin of the plate. The laterals in some cases arise con-
fluently with the edges of the hinge plate, as in NS. selbyensis or
Mulinia densata, or they may be set some distance from the margin,
as in Mactra nasuta or 8. voyt.

It has been shown above that the general shape of the shell, the
position of the umbones, and the character of the pallial sinus are
more inconstant than are the hinge characters, and therefore they
are only of secondary importance in defining a mactrine shell.

In the systematic portion of this paper the species have been
erouped into subgenera and sections wherever it has been possible.
These lesser divisions are of use inasmuch as they show the relation-
ships that exist within a genus. The subgeneric groups, as defined
by Dall, are based upon the differences of the dental armature, due
consideration having been given to any other character of the shell
that appeared to have a taxonomic value.

THE HISTORY OF THE MACTRINAE

The geologic and geographic distribution of the West Coast
Mactrinae have a phylogenetic as well as an economic interest. The
oldest known species, Spisula ashburnert (Gabb), has been reported
from the Horsetown Beds; it has a long range, being found abund-
antly in the upper portion of the Chico, where it is associated with
S. gabbiana (F. M. Anderson) and S. chicoensis, new name. The

274 University of Calforma Publications in Geology — [Vou. 9

first two of these are known to occur at upper Cretaceous localities
from British Columbia to the Santa Ana Mountains, California.

Two mactrine species are now known from the Martinez Eocene
of this region. One, Mactra (?) tenwissima Gabb, has been recognized
by Dickerson,“ in material obtained from the Martinez group of
Lower Lake, Lake County, California. The other, Spisula (?) weaveri
Packard, appears to be characteristic of the lower Eocene of Mount
Diablo and of the Santa Ana Mountains, California. The genera of
these forms have not been definitely determined, due to inability
to observe the hinges, and therefore they can have no place in a
phylogenetic discussion.

Four species are known from the upper Eocene. Two, Spisula
merriami, n. sp., and S. tejonensis, n. sp., have a wide geographic
range, occurring abundantly at a number of Tejon localities through-
out the state, and S. tejonensis, n. sp., has been questionably
recognized by the writer from strata of approximately the same age
at Vader, Washington. The new species Spisula acutirostrata occurs
at the type locality of the Tejon group in California. The species
S. callistaeformis Dall, comes from the Stepovak series of Alaska.

Spisula albaria ramonensis, n. var., and possibly S. occidentalis
(Gabb) are restricted to the Agasoma gravidum zone, which according
to B. L. Clark is of Oligocene age.

Eleven species and one variety of well-known Mactrinae occur
within the Miocene strata of this region. This number is increased
by the following imperfectly known forms: Spisula lenticularis
(Gabb), S. montereyana (Arnold) and Mulinia landesi (Weaver).
Three and possibly four mactrine species are known in the Mon-
terey series, aS now recognized, exposed in the vicinity of Mount
Diablo, California. S. catilliformis Conrad has been reported from
the Temblor of the Kern River district, Kern County, California,
associated with a fauna that is thought by B. L. Clark to be equiva-
lent to the Arca montereyana zone of the Mount Diablo section.
S. selbyensis, n. sp., and a mulinoid form not distinctly separable
from Mulinia densata Conrad also occur in this zone. Its variety,
M. densata var. minor occurs in the Turritella ocoyana zone of
the Coalinga district. The lower San Pablo mactrine fauna con-
sists of Spisula abscissa (Gabb), 8. albaria (Conrad), S. catilliformis

17 Dickerson, R. E., Fauna of the Martinez Eocene of California, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 8, p. 96, 1914.

GEOLOGIC AND GEOGRAPHIC RANGE OF THE PACIFIC COAST MACTRINAE

Pleis- * A
Bacon recone Pliocene Miocene Oligocene Eocene Cretaceous
r ~—

|
|

Purisma-Etchegoin fauna
Upper San Pablo fauna
Lower San Pablo fauna
Scutella breweriana zone
Agazoma gravidum zone

Vancouver Island

San Francisco

Panama

Merced fauna

Jacalitos fauna
San Lorenzo fauna
Tojon fauna
Martinez fauna
Chico fauna
Horsetown fauna

Alaska
Straits of Juan de Fuca

! Turritella ocoyana zone
} Turritella inezana zone

S
5
E

s

ic

5

S
CI

3
2

&
x

x Santa Barbara
x» San Pedro fauna

x» San Pedro

b
&
3
a
Ss
=
x

i
H
!
j

Jactra californica Conrad
Mactra dolabriformis (Conrad)
Jictra exoleta Gray
yactra (7) gibbsana Meek
Mictra (?) montereyana Arnold

x
H

x x x San Diego

x
x

\ictra (%) stantoni Arnold
\uctra (2) tenuissima Gabb
‘Victra trampasensis, N. sp.
Yolinia alta (Weaver) .....
Molinia densata var. minor Arnold
Vilinia landesi (Weaver)
Molinia pabloensis, n. sp. ..
Mnlinia undilifera (Weaver)
Sysula abscissa (Gabb) ......
Sjisula acutirostrata, n. sp.
fylsula aibaria (Conrad)
{yisula albaria var. ramonensis, n. var. .
)kula ashburnerii (Gabb)
SMsula brevirostrata, n. sp
Sisula callistaeformis Dall.
Hisula catilliformis Conrad ..

os oe see
.
il on

Ww)

U6 EA0Cs

a
tat
eu

5 y
x ee
ua}

« ayLstee ol Vig

=

ne)

=!

ty '
hc OS
oa e
4 ”
bo na
< te

Coes blowid

hiow ra

“atorete arin z!

Papen a oe

Eee
(Seasdh
nic i fh

1916] Packard: Mesozoic and Cenozoic Mactrinae DD

Conrad, Mulinia densata Conrad and M. pabloensis, n. sp. Only
the first of these is restricted to this portion of the series, its highest
known range being the base of the Astrodapsis whitneyi zone of the
middle San Pablo. To this zone belongs the earliest undoubted
mactroid species, M. trampasensis, n. sp. To the upper San Pablo
belong the following forms: Spisula albaria (Conrad), S. catilli-
formis Conrad, Mulinia densata (Conrad) and M. pabloensis, n. sp.
The last-mentioned is restricted in its upward range to the top of the
San Pablo.

The exact stratigraphic position of the following Miocene species
has not been definitely determined with reference to the standard
California section: Mulinia landesi (Weaver), M. alta (Weaver) and
M. undilifera (Weaver).

The following species range through the Jacalitos into the
Etchegoin formation: Spisula albaria (Conrad), S. catilliformis
Conrad and Mulinia densata Conrad. S. coalingensis (Arnold) is
known only from the Etchegoin. Two other species, S. voyt (Gabb)
and S. brevirostrata, n. sp., occur at a questionably equivalent strati-
graphic position in the Wildeat series of Humboldt County,
California.

The Merced fauna of the San Francisco Peninsula has yielded the
following mactrine species: Spisula albaria (Conrad), S. catilli-
formis Conrad, 8. mercedensis, n. sp., and S. falcata (Gould). Two
of these, S. albaria (Conrad) and S. mercedensis, n. sp., became
extinct at the close of the Pliocene.

The San Pedro or Pleistocene fauna is characterized by the
appearance of two mactroid species of widely different types. The
known Pleistocene species include: Mactra californica Conrad,
M. exoleta Gray, Spisula catilliformis Conrad, 8. falcata (Gould)
and S. hemphillu (Dall). S. voyi (Gabb) may be mentioned here,
since it is known to occur both in the Pliocene and Recent faunas.
Its absence from the San Pedro fauna may be due to the fact that
it is a northern species, being at present lmited in its southward
range by the Straits of Juan de Fuca.

Three species, Mactra dolabriformis (Conrad), M. nasuta Gould,
and Spisula planulata (Conrad) are known definitely only in the
Recent fauna. To these should be added the above-mentioned
Pleistocene forms, giving a list of four mactroid and five spisuloid
species known to the waters of the Pacifie Coast north of Mexico.

276 University of California Publications in Geology [Vo. 9

The geographic range of the Recent species and the vertical range
of the fossil species are shown on the accompanying chart, in which
the periods are divided into stages according to the faunas.

PHYLOGENY OF THE PACIFIC COAST MACTRINAE

The genus Spisula is the first genus of the Mactrinae to appear
within this Pacific Coast region. It is doubtfully represented in the
Horsetown Beds by S. ashburnerii (Gabb), the typical species of
the subgenus Cymbophora. Higher in the Cretaceous, this form is
associated with S. gabbiana (F. M. Anderson) and S. chicoensis,
new name. These three are characterized by having a spoon-shaped
chondophore with raised margins and a type of right cardinal in
which the anterior arm is lacking. This typical Cretaceous group
is replaced in the Eocene by the subgenus Hemimactra in which the
chondophore is submerged below the level of the hinge plate and in
which the right cardinal bears two well-developed arms. By the
middle of the Miocene this subgenus was the dominant one of the
family, including the great majority of the Tertiary species, many of
which had a wide geographic range. The genus Spisula reached its
maximum during the late Miocene, declining in importance until at
present it is represented by but one more species in this Coast region
than is the younger genus JMJactra.

The first undoubted mactroid species appears in the San Pablo.
It is not until the Pleistocene that this genus holds an important
place in the fauna of the region, being represented at that time by
two groups of species. These two subgenera, Mactrotoma and Mac-
trella, are quite widely separated groups. The latter appeared earlier
on this Coast, being represented by the species Mactra trampasensis,
n. sp. To the former belong the greater number of Recent species.
The genus Mactra appears at present to be at its maximum of de-
velopment.

The phylogenetic history of the genus Mulinia on the West
Coast of the United States is characterized by its sudden appear-
ance, rapid dispersal and abrupt disappearance. It first appears
in the early Miocene. By the time the San Pablo stage was reached,
this genus had become differentiated into several types, that were
distributed over the coast from Washington to southern California.

1916] Packard: Mesozoic and Cenozoic Mactrinae PAT

By the close of the Neocene these forms became extinct. The genus
is now known on the Pacific Coast only from the Panama province,

The Miocene was the period of the greatest generic and specific
differentiation of the family. Previous to that time the species
were few in number and relatively constant in shape. During that
period a considerable number of new forms appeared, most of which
were exceedingly variable, giving rise to a number of species, many
of which became extinet during the Pliocene. A few of the less
variable forms persisted through to the Recent. Specifie differen-
tiation increased until the present fauna is characterized by clearly
defined species which are in general not closely related to one an-

other.

CONCLUSIONS

Of all the principal parts of the shell, the mactrine hinge is the
least variable within the limits of a single species. It varies some-
what as regards relative height or thickness of the teeth, but the
relative positions of the dental elements with reference to one another
are remarkably constant for a given species, and therefore serve as
important bases for specific classification.

The known mactrine forms include five mactroid species, one of
which is here described for the first time. The genus Spisula is
represented by twenty-three species, six of which are new. The hinges
of eighteen of these have been studied. Three species and two vari-
eties of Mulinia are recognized, one of the species being considered

as new.
SYSTEMATIC DESCRIPTIONS
Superfamily MACTRACEA Gray, 1837
Resilium situated on a chondophore; bifid cardinal in the left
valve fits below the two cardinal arms of the right valve.*®
Family MACTRIDAE Gray, 1837

Shell trigonal, equivalve; posterior gape more or less evident;
umbones prosogyrate; hinge plate well-developed, subtrigonal in
18 This and the following definitions of the family, genera, subgenera and

sections are based almost exclusively upon Dall’s paper published in the
Proceedings of the Malacological Society of London, vol. 1, pp. 203-213, 1895.

278 University of California Publications in Geology [Vou. 9

shape; ligament internal or external; chondophore excavated; a
bifid /\-shaped cardinal in the left valve fitting between the two
arms of the cardinal of the right valve; posterior and anterior
laminae well-developed ; accessory lamellae often present ; pallial line
often sinuated; siphons united; epidermis present.

Subfamily MACTRINAE Dall, 1894

Shell subequilateral; gape slight in most forms, never pro-
nounced; siphons may he retracted within the shell; epidermis
covering the siphons not markedly developed.

Genus Macrra Linnaeus, 1758

Type Mactra stultora Linnaeus
Plate 12, figures la and 1b
Shell ovate-trigonal, subequilateral; chondophore roofed at the
apex; spur distinct; ligament separated from the resilium by a
shelly ridge.

Subgenus Mactrotoma Dall, 1894
Type Mactra fragilis Gmelin

Shell with a depressed band on the dorsal area; sculptured; um-
bones adjacent; gape pronounced; resilifer large, shallow, apically
roofed; cardinals prominent, but thin; posterior arm of the cardi-
nals overhangs the chondophore; accessories on the posterior arms;
anterior laminae arising from the dorsal sinus; pallial line distant;

epidermis thin and silky.

Section Mactrotoma Dall, 1894

Mactra nasuta Gould is the first species mentioned by Dall.
Accessories coalescent with laterals and cardinals.

MACTRA NASUTA Gould
Plate 12, figures 2a, 2b and 2c
Mactra nasuta Gould, Boston Soc. Nat. Hist., vol. 4, p. 88, 1851; Dall,
Nautilus, vol. 8, p. 39, 1894; Keep, West Coast Shells, p. 105, 1911.
Mactra californica Deshayes, Proc. Zool. Soc. London, 1854, p. 68.
Mactra fragilis Carpenter, Brit. Assn. Rept. 1856, p. 304.
Mactra deshayesii Conrad, Am. Jour. Conch., vol. 3, appendix, p. 46, 1868.

1916] Packard: Mesozoic and Cenozoic Mactrinae 279

The dimensions of the specimen figured are: length 33.5 mm.,
height 23 mm., convexity 6 mm.

The lack of the suleate beaks, the more pronounced gape, the
more ventricose form, besides several details of the hinge will serve
to separate this species from Mactra californica, with which it is
often associated.

This Recent species was described from a specimen obtained from
San Pedro, California. The species is not certainly known to occur
in beds older than the Recent.

Occurrence.—Recent: San Pedro, California, to West Colum-
bia. (Dall).

Section Simomactra Dall, 1894
Type Mactra dolabriformis (Conrad )

Laminae lacking accessories.

MACTRA DOLABRIFORMIS (Conrad)
Plate 12, figures 3a, 3b and 3c

Spissula19 dolabriformis Conrad, Am. Jour. Conch., vol. 3, p. 193, 1867.

Spisula dolabriformis (Conrad), op. cit., appendix, p. 44.

Mactra dolabriformis Conrad, Dall, Nautilus, vol. 7, p. 138, pl. 5, fig. 1,
1894; Keep, West Coast Shells, p. 105, 1911.

This species was described from a Recent specimen obtained
from Panama. Neither figure nor dimensions of this specimen were
given. Dall in a redescription of this form gives the following
dimensions: length 90 mm., height 63 mm., convexity 13 mm.

This species might be confused with Sprsula falcata, from which
it differs in its mactroid type of hinge, more elongate shape and
more pronounced umbonal ridge.

Occurrence.—Recent: San Diego, California to Panama (Dall).

Section Micromactra Dall, 1894
Type Mactra californica Conrad
Shell small with suleate beaks.

19 This spelling of the generic name is evidently a typographical error
since it is spelled correctly by the same writer in the appendix of the
same volume.

280 University of California Publications in Geology (Vor. 9

MACTRA CALIFORNICA Conrad
Plate 16, figures 4a, 4b and 4c

Mactra californica Conrad, Jour. Acad. Sci., Philadelphia, vol. 7, p. 240,
pl. 18, fig. 12, 1837; Dall, Nautilus, vol. 8, p. 40, 1894; Dall, Trans. Wagner
Inst. Sci., vol. 3, pt. 4, p. 876, 1898; Arnold, Mem. Cal. Acad. Sci., vol. 3,
p. 174, pl. 19, fig. 2, 1903.

Mactra augusta Deshayes, Proc. Zool. Soc., London, 1854, p. 67.

This species was described by Conrad as follows:

Shell triangular, compressed, equilateral; posterior margin rectilinear;
posterior side with a carinated, rectilinear, submarginal line; beaks promi-
nent, suleated; epidermis brown, with concentric wrinkles; teeth lamellar,
large, very prominent.

The hinge plate of this species is broad and flat; chondophore
shallow, apically roofed, triangular in shape, overhung but slightly
by the arm of the cardinal; left cardinal prominent, high, thin,
without accessories; anterior arm longer than the posterior, neither
reaching to the ventral margin of the hinge plate; right cardinal
also high, thin, arms fused along the dorsal side of the tooth;
anterior arm makes a relatively wide angle with the anterior dorsal
margin of the shell; laminae smooth; anterior lateral bifid, the
dorsal portion being usually the thinner and possessing the char-
acter of a lamella; this tooth is short and high, originating as a low
ridge dorsal to the middle of the anterior cardinal arm and extend-
ine parallel to the ventral margin of the hinge plate; anterior
ventral lamina very small, inserted upon the dorsal margin of the
shell; posterior laminae short, the small dorsal one arising from the
shell margin. Pallial line distant, with a deep and rounded sinus
which reaches nearly to the middle of the shell and joins conflu-
ently for a short distance with the pallial line. The measurements
of the type as inferred from the original cut are: length 36 mm.,
height 23 mm.

This species has been confused with Spisula catilliformis, the
latter having been listed in much of the literature under the name
of the former. Specimens of these two species are easily distin-
guishable. M. californica resembles S. falcata in outline, but it is
separable from that species upon the basis of its suleate beaks, and
prominent cardinal with its widely diverging arms. It differs from
M. nasuta in being more ventricose, and in possessing longer lat-

erals.

1916] Packard: Mesozoic and Cenozoic Mactrinae 281

This species was described from a Recent specimen obtained from
near Santa Barbara, California.

Occurrence.—Recent: Straits of Juan de Fuca to Central America
(Dall). Pleistocene: San Diego and San Pedro (Arnold).

Subgenus Mactrella Gray, 1853
Type Mactra alata Spengler

Shell thin, ventricose, trigonal, with a ridge marking off the
posterior dorsal area; umbones prominent; dental armature concen-
trated ; normal, narrow ligament; anterior laminae very short.

MACTRA EXOLETA Gray

Plate 12, figures 4a and 4b; plate 13, figure 2

Mactra exoleta Gray, Mag. Nat. Hist. 1837, p. 372; Carpenter, Proc. Zool.
Soc., London, pt. 24, p. 200, 1856; Brit. Assn. Repts. 1856, p. 246; Dall,
Nautilus, vol. 8, p. 40, 1894; Arnold, Mem. Cal. Acad. Sci., vol. 3, p. 175, pl. 19,
fig. 4, 1903.

Lutraria ventricosa Gould, Boston Jour. Nat. Sci., vol. 4, p. 88, 1851.

Mulinia ventricosa A. Adams, Annals Nat. Hist. N. Y., vol. 5, p. 517, 1852.

Mactrella exoleta Carpenter, Brit. Assn. Repts. 1863, p. 543.

Shell subtrigonal, very ventricose; beaks prominent, slightly
anterior to the middle of the shell; anterior dorsal edge straight ;
anterior end very broad and regularly rounded; posterior dorsal
edge convex, sloping abruptly to the truncated posterior extremity ;
base broadly arcuate; a prominent umbonal ridge extends from the
beaks to the posterior extremity; the area posterior to this line is
nearly flat. Surface smooth or slightly roughened by lines of
growth.

Hinge plate rather narrow; chondophore deep, apically roofed,
divided into two areas by a well-developed shelly ridge charac-
teristic of the genus Mactra, overhung by an accessory lamella, which
arises from the posterior arm of the left cardinal; left cardinal
prominent; posterior arm slightly shorter than the anterior; cardinal
reaching ventrally from the dorsal margin of the shell to the ventral
margin of the hinge plate; right cardinal with a very heavy anterior
arm, which is appressed to the shell margin and extends about three-
fourths of the distance to the ventral margin of the hinge plate;
posterior arm thin and slightly overhanging the resilifer; arms not

282 University of California Publications in Geology [Vou. 9

coalescent dorsally ; laminae smooth, the groove between the anterior
ones being very deep; anterior lateral very short, distant from the
cardinal and arising from the ventral edge of the hinge plate; pos-
terior one also short and distant from the umbones; ventral lamina
well developed, dorsal ones very small. Pallial sinus very shallow
and angular. The dimensions of the specimen figured in this paper
are: length 44 mm., height 34 mm., convexity 13 mm.

This ventricose and angulated species is easily separable from
the other known Pacific Coast Mactrinae upon the basis of the gen-
eral shape, which is quite constant in all of the specimens examined.

Mactra exoleta has been reported from the Pliocene of Wash-
ington but the specimen figured scarcely seems determinable.?°

This species was described from a Recent specimen.

Occurrence—Recent: San Diego, California, to Guayquil, Equa:
dor (Dall). Pleistocene: San Diego, San Pedro (Arnold) ; Newport,
California.

MACTRA TRAMPASENSIS, n. sp.
Plate 13, figure 3; plate 16, figures 1 and 2

Shell medium-sized, very ventricose, trigonal to subovate, nearly
as high as long, and nearly equilateral; sculptured by faint distant
concentric lines; beaks prominent, incurved, distant; posterior dorsal
slope somewhat concave, with an ill-defined escutcheon; anterior
dorsal slope concave, marked by a well-defined impressed lunule;
anterior and posterior extremities about equally rounded, ventral
margin broadly rounded. Hinge plate narrow; chondophore deep,
nearly circular in outline, shghtly overhung by the cardinal, prob-
ably roofed by a spur; left cardinal arms heavy; anterior arm
slightly longer than the posterior, reaching from the dorsal margin
of the shell to the ventral margin of the hinge plate; right cardinal
partially destroyed; anterior arm strong, low, apparently confluent
with the ventral lamina; laminae smooth; anterior lateral confluent
with the anterior arm of the cardinal; posterior lamina low, long.
Pallial line is unknown. The dimensions of the type specimen are:
length 48 mm., height 38 mm., convexity 14 mm.

The distinctive shape readily separates this species from other
Pacific Coast Mactrinae. The few specimens that are known show
but little variation in general shape.

20 Reagan, A. B., Kan. Acad. Sci., vol. 22, p. 212, pl. 4, figs. 42a, 42b, 1909.

1916] Packard: Mesozoic and Cenozoic Mactrinae 283

The type was obtained from University of California Loeality
1237: Top of knob about one-quarter of a mile south-east of Bur-
ton’s and about one and one-half miles north of Los Trampas Creek,
Concord Sheet, Contra Costa County, California.

Occurrence.—Miocene: San Pablo group, Contra Costa County,
California.

Genus SPISULA Gray, 1837
Type Mactra solida (Linnaeus) Gray

Shell generally small, nearly equilateral; beaks adjacent; dorsal
area not set off by a definite ridge or keel; gape obsolete; ligament
and resilium not separated by a shelly partition; ligament sagitate,
partially external; chondophore shallow, often roofed over by a
spur; cardinal small and often overhanging the chondophore;
anterior arm of the right cardinal is close to the dorsal margin of
the shell; laminae heavy, often grooved; pallial sinus small, evenly
rounded; epidermis thin.

Subgenus Hemimactra Swainson, 1840

Type Mactra solidissima Dilliwyn
Plate 6, figures 1a and 1b
Shell large, trigonal; dorsal area not distinctly grooved; teeth
somewhat concentrated; cardinals small, compressed; anterior arm
of the cardinal generally confluent with the ventral lamina; the
laminae are often distinctly grooved.

Section Mactromeris Conrad, 1868
Type Mactra polynyma Stimpson

Laminae smooth, ventral lamina not confluent with the anterior

arm of the cardinal.

SPISULA VOYI (Gabb)
Plate 13, figure 4; plate 14 and plate 15

Callista voyi Gabb, Pal. Cal., vol. 2, p. 24, pl. 5, fig. 41, 1869.

Mactra ovalis Gould, Middendorf, Reise in den Aeussersten Norden und
Osten Siberiens, bd. 3, p. 368, 1843-1844.

Spisula polynyma (Stimpson), Dall, Nautilus, vol. 7, p. 138, 1894.

Spisula polynyma (Stimpson) var. alaskana Dall, Nautilus, vol. 8, D.
40, 1894.

Spisula alaskensis Dall, U. S. Geol. Surv. Prof. Paper, no. 59, p, 131, 1909.

Mactra (Spisula) alaskana Dall, Baker, Nautilus, vol. 24, p. 46, 1910.

284 University of Califorma Publications in Geology — [Vor. 9

This species was described by Gabb as follows:

Shell broad, inequilateral; beaks in advance of the middle; cardinal
margin nearly straight and sloping; anterior end very much produced,
rounded and narrow; posterior end obliquely truncated; base broadly and
regularly rounded. Surface marked by numerous irregular and rather ~
strong lines of growth.

The hinge plate of this species is wide, the chondophore oblique,
shallow, very slightly overhung by the posterior arm of the cardi-
nal; left cardinal heavy, high, situated on the dorsal portion of the
hinge plate; arms heavy, of equal length, free from accessories,
ventral sinus excavated; right cardinal low, anterior arm thick,
appressed to the shell margin; posterior arm very thin; anterior
lateral low, acutely pointed, its dorsal base extending back of, and
parallel to the anterior arm of the cardinal; posterior lateral low,
long, reaching as an indistinet ridge nearly to the umbones; pos-
terior laminae low and long; anterior laminae very short; dorsal one
arises from the margin of the shell. Pallial sinus of the Recent
specimens deep, rounded and oblique to the pallial line. This is not
shown in the plesiotype. The dimensions of the plesiotype are:
leneth 85 mm., height 60 mm., convexity 18 mm.

This species was described from a fossil specimen obtained from
below Bear River, Humboldt County, California. Several speci-
mens from Eel River, Humboldt County, were labeled Callista voyi
by the State Geological Survey. One of these corresponds in outline
and size to Gabb’s conventional figure. The hinge of this specimen
has been exposed. Its mactrine character was first recognized by
Dr. Merriam.2!. The complete dentition is now known from the
specimens obtained from the above-mentioned region. A study of
these together with the type shows that they are identical with
Spisula alaskana of the Recent fauna.

The hinge of this species might be confused with that of
S. catilliformis. It differs from that species in that the anterior
lateral is never fused to the anterior arm of the cardinal and that
the posterior laminae are much more elongate.

The fossil forms are slightly more ventricose than are the few
available Recent specimens. The general shape of both the fossil
and Recent specimens varies considerably as regards the relative

lengths of the shells.

21 Merriam, J. C., A list of the type specimens in the Geological Museum
of the University of California, etc., Berkeley, 1895.

1916] Packard: Mesozoic and Cenozoic Mactrinae 285

Occurrence.—Recent: Iey Cape, Alaska, to Neah Bay, Washing-
ton (Dall). Phocene: Wildeat group, Humboldt County, California.

SPISULA CATILLIFORMIS Conrad
Plates 17, 18 and 19

Spissula22 catilliformis Conrad, Am. Jour. Conch., vol. 3, p. 1938, 1867.

Standella california (Conrad), Carpenter, Brit. Assn. Rept. 1863, p. 640
(not of Conrad 1837 nor of Deshayes 1852).

Spisula catilliformis Conrad, Dall, Nautilus, vol. 7, p. 1387, pl. 5, fig. 3,
1894; Arnold, Mem. Cal. Acad. Sci., vol. 3, p. 176, pl. 19, fig. 5, 1908.

Spisula catilliformis, var. alcatrazensis Arnold, Smithsonian Mise. Coll.,
vol. 50, p. 487, pl. 56, fig. 6, 1907.

Conrad described this species as follows:

Suboval, inequilateral; anterior side slightly flattened or contracted; pos-
terior side with an oblique shallow groove or fold; lines of growth coarse
and prominent; lunule very long, elliptical; ventral margin tumid pos-
teriorly; cardinal pit oblique, large; pallial sinus extending beyond the
middle of the valve.

The hinge plate of this species is wide; chondophore very large
and shallow, overhung slightly by the arm of the cardinal and by a
prominent spur; left cardinal heavy, large, situated on the dorsal
edge of the hinge plate; arms of nearly equal length; ventral sinus
wide, flat; right cardinal low, anterior arm small, appressed to the
dorsal margin of the shell; posterior arm thin, overhanging the
chondophore; laterals heavy, anterior lateral short, high and fused
to the dorsal side of the anterior cardinal arm; posterior lateral
longer and not quite so high as the anterior one; laminae very short,
heavy, and close to the umbones; anterior dorsal lamina nearly in
the same plane with the anterior cardinal arm. Pallial sinus deep,
rounded, reaching nearly to the middle of the shell. The dimensions
of the type as given by Conrad are equivalent to a length of 117.3
mm., and a height of 98.3 mm.

There is considerable variation in the outlines and especially in
the convexity of the Recent specimens. If the fossil specimens are
considered it is found that the variation in shape is quite marked.
Those obtained from a single collecting locality from the base of the
San Pablo of the Mount Diablo region vary considerably in outline,
being more variable than the Recent specimens, although they possess
hinges that are nearly identical with those of the Recent fauna.

The type of the variety alcatrazensis of Arnold was obtained from

22 See foot-note 19.

286 University of California Publications in Geology [Vo. 9

the Fernando formaticn from the Alcatraz asphalt mine near
Sisquoe, Santa Barbara County, California. It is evident from the
original description that this variety is based solely upon the general
shape, for it is stated that the ‘‘hinge and the interior’’ are ‘‘quite
similar to the typical form’’. It appears to differ from the typical
species in its more central beaks, more depressed anterior margin
and more truncated anterior extremity, but similar differences in
shape are known to occur within the limits of the typical species
and such characters are there considered as having little taxonomic
significance.

This species has been confused with the lutrarine species Schiz-
othaerus nuttallii, but it differs markedly from that species in the
character of the siphonal gap and in the type of the hinge. It
might be confused with S. mercedensis, which is a more tumid form,
lacking the pronounced posterior flexure and having the anterior
lateral distinctly separated from the arm of the cardinal.

The type of this species was described from a Recent specimen
obtained from Panama.

Occurrence.—Recent: Straits of Juan de Fuca to San Diego, Cali-
fornia (Dall). Pleistocene: San Pedro, San Diego (Arnold). Plio-
cene: Merced group. Miocene: San Pablo group; Temblor (J. P.
Smith).

SPISULA MERCEDENSIS, n. sp.
Plate 13

Shell large, ventricose, inequilateral, the beaks being consider-
ably anterior to the middle of the shell; anterior dorsal edge short,
slightly concave, with a faint suggestion of a lunule; posterior dorsal
edge gently convex, curving regularly to the rounded extremity ;
anterior end evenly rounded; base broadly arcuate; umbones small,
sharply pointed; an indistinct posterior flexure extends from the
umbones to the base, much as in Spisula catilliformis Conrad. Sur-
face roughened by numerous irregular lines of growth. Hinge plate
wide, chondophore shallow, wide, overhung but slightly by the pos-
terior arm of the cardinal; left cardinal large, arms of equal length,
high; anterior lateral short, situated dorsal to the anterior arm of
the cardinal; posterior lateral high and acutely pointed. Hinge of
the right valve unknown. Pallial sinus not observed. The dimen-
sions of the type are: length 124 mm., height 93 mm., convexity

32 mm.

1916] Packard: Mesozoic and Cenozoic Mactrinae 287

This species differs from Spisula catilliformis, with which it is
often associated, in its general outline; in being more ventricose ; in
having an indistinct posterior flexure and in the separation of anterior
lateral from the anterior arm of the cardinal.

The type of this species was obtained in the marine cliffs of the
Merced group, near Mussel Rock, San Mateo County, California.

Occurrence.—Plhocene: Merced group, San Mateo County, Cali-
fornia.

SPISULA HEMPHILLII (Dall)
Plates 21 and 22

Mactra hemphillii Dall, Nautilus, vol. 7, p. 137, pl. 5, fig. 2, 1894.

Spisula hemphillii (Dall). Nautilus, vol. 8, p. 40, 1894; Arnold, Mem.
Cal. Acad. Sci., vol. 3, p. 175, pl. 19, fig. 3, 1903; Keep, West Coast Shells,
p. 106, 1911.

Dall described this species as follows:

Shell large, thin, inflated, subequilateral, creamy white with a yellow,
thin epidermis, which over the body of the shell in young shells is beauti-
fully evenly concentrically striated and on the posterior dorsal area is irregu-
larly wrinkled, with an elevated raphe of epidermis at the margin of the
area; beaks rather prominent, the anterior end of the valves longer than
the posterior; posterior dorsal slope excavated; lunule obscure, escutcheon
marked by prominent elevated radial lines of epidermis; the dorsal margin
pouting in front of the ligament, the posterior slope convex, the posterior
flexure faint, but marked by a recession of the ventral border of the valves,
which gap but very little and not at all in front; anterior end rounded,
but smaller than the posterior; ventral border arcuate; hinge and pallial
sinus much as in the last species (S. catilliformis), except that the sinus
is smaller and less depressed.

Hinge plate rather wide, chondophore deep, apically roofed by a
prominent spur, but not overhung by the cardinal arms; left eardi-
nal high and heavy, situated on the dorsal portion of the hinge
plate; arms of equal length; ventral sinus deeply excavated; right
cardinal low, the cardinal arms not fused medially, anterior arm the
heavier, posterior arm short and thin; anterior lateral short, high,
round-topped, distinctly separate from and in nearly the same plane
with the anterior cardinal arm; laminae short and heavy; anterior
ventral lamina distant from, but nearly in alignment with the
anterior cardinal arm; dorsal anterior lamina represented by a
short, low process arising from the margin of the shell; posterior
dorsal lamina shorter and thinner than the posterior ventral one.

288 University of California Publications in Geology [Vou. 9

Pallial sinus deep, oblique to the ventral margin. The dimensions
of the type, which was a Recent specimen from San Diego, California,
were given as: length 120 mm., height 93 mm., convexity 25 mm.

A considerable number of specimens of this species have been
available for study. The species appears to be quite constant as
regards the general shape as well as the dental armature.

This species might be confused with S. catilliformis. From that
species it is separable on the basis of its shape; longer laminae;
the separation of the anterior lateral from the arm of the ear-
dinal; and the more oblique type of pallial sinus.

Occurrence.—Recent: San Pedro to San Diego, California (Dall).
Pleistocene: San Pedro (Arnold) ; Newport, California.

SPISULA OCCIDENTALIS (Gabb)
Plate 23, figures 1, 2 and 3

? Hemimactra occidentalis Gabb, Pal. Cal., vol. 2, p. 54, pl. 15, figs. 13
and 13a, 1869.

This species was described by Gabb as follows:

Shell thin, subovate, inequilateral; beaks small, closely approximating,
placed about two-fifths of the length from the anterior end, which is broadly
excavated above, and prominently, though narrowly rounded below; posterior
end convexly and obliquely sub-truncated; cardinal margin sloping and
nearly straight, base broadly and regularly convex; a moderately distinct
angle runs from the beaks to the posterior basal margin. Surface covered
by small but moderately prominent and pretty regularly placed lines of
growth.

The hinge plate is wide; chondophore deep and slightly roofed;
left cardinal is somewhat broken, but the remaining portion shows
that the arms were of nearly equal length and that the tooth was
situated medially upon the hinge plate; arms of the right cardinal
heavy, the anterior one not confluent with, nor in the same plane
with the ventral lamina; laterals but imperfectly preserved, the
anterior one arising from the ventral edge of the hinge plate, and
distant from and not in alignment with the anterior cardinal arm;
laminae short and low, the posterior ventral one being the largest ;
ventral sinus is restricted by an abrupt inbending of the ventral
margin of the hinge plate. Pallial sinus extends to the middle of
the shell. The dimensions of the type obtained by Gabb from
the vicinity of Martinez, Centra Costa County, California, were
given as equivalent to: length, 69 mm., height, 59 mm., convexity,

1916] Packard: Mesozoic and Cenozoic Mactrinae 289

15 mm. Those of the plesiotype are: length, 74 mm., height, 53
mm., convexity, 15.5 mm.

Neither the type nor any specimens that were labeled by the
members of the State Geological Survey are known to exist. Sev-
eral specimens from the general region from which the type was
obtained appear to satisfy the description of this species as given by
Gabb. One of these has been made the plesiotype of this species.

Although the ratio of the height to the length of this species
is quite variable, this form is quite readily separable from other
known mactrine species. Certain specimens might possibly be con-
fused with a young specimen of S. catilliformis, but the lack of the
characteristic posterior flexure of that species and the widely differ-
ent type of dentition easily characterizes Gabb’s species.

Occurrence.—Oligocene: Agasoma gravidum zone, Mount Diablo
region, California.

SPISULA ABSCISSA (Gabb)
Plate 23, figure 4, and plate 24, figure 2
Schizodesma abscissa Gabb, Pal. Cal., vol. 2, p. 20, pl. 4, figs. 34 and
34a, 1869.

This species was described by Gabb as follows:

Shell large, thick, irregularly subquadrate; beaks large, prominent,
pointed forwards, nearly central; anterior end obliquely truncated; base
broadly rounded; posterior end very strongly and abruptly truncated, the
truncation ending at an angular ridge which passes from the beaks to the
posterior basal angle. Surface marked by rough irregular lines of growth.
Hinge composed of large robust teeth; lateral teeth long and thick.

A specimen obtained from the vicinity of San Pablo Bay, Cali-
fornia, appears to satisfy the requirements of the description of
this species as given by Gabb. The type being lost, a specimen
from University of California Locality 1608, is here taken as the
plesiotype.

The hinge plate is rather broad, chondophore wide and deep,
slightly overhung by the arm of the cardinal; left cardinal rather
small, arms of equal length, extending ventrally to about the middle
of the hinge plate; laterals long and rather thin, smooth, flat-topped,
distant from the beak, the anterior one not reaching to the arm
of the cardinal. Hinge of right valve unknown. The dimensions
of the type as measured on the original figure are: length, 100 mm.,
height, 98 mm., convexity, 36 mm.

290 University of California Publications in Geology (Vou. 9

This species is extremely variable in general shape. It is typi-
cally more quadrate in outline than the associated mulinoid species,
and it lacks the prominent beaks of these species, besides differing
in details of the hinge. The type of this species was obtained from
the indefinite locality of San Pablo Bay, Contra Costa County,
California.

Occurrence—Miocene: Lower San Pablo group, Mount Diablo
region, Contra Costa County, California.

SPISULA ALBARIA (Conrad)
Plate 24, figure 1; plate 25, figures 3 to 8

Mactra albaria Conrad, Am. Jour. Sci., 2d. ser., vol. 5, p. 432, fig. 4, 1848;
Dall, U. S. Geol. Surv. Prof. Paper 59, p. 150, fig. 4, 1909 (reprint); Arnold,
U. S. Geol. Surv. Bull 396, p. 30, pl. 19, fig. 4, 1909.

Mactra diegoana Conrad, House Doc. no. 129, p. 14, 1855; Pacific R. R.
Repts., vol. 5, p. 325, pl. 5, fig. 45, 1855.

Standella planulata, Gabb, Pal. Cal., vol. 2, p. 91, 1869; not of Conrad 1837.

Spisula albaria (Conrad), Dall, U. S. Geol. Surv. Prof. Paper 59, p. 130,
pl. 10, fig. 1, 1909.

? Spisula precursor Dall, U. S. Geol. Surv. Prof. Paper 59, p. 131, pl. 14,
fig. 10, 1909.

Conrad described this species as follows:

Triangular, ventricose; beaks medial; umbonal slope angulated; anterior
and posterior margins nearly equally oblique; posterior extremity trun-
cated, direct; basal margins regularly curved.

The hinge of a specimen from the Merced group, near Capitola,
Santa Cruz County, California, is best known and will serve as the
basis for the description.

Hinge plate wide, chondophcre oblique, rather deep and_ par-
tially roofed by an accessory; spur distinct in most specimens; car-
dinals large, heavy, arms widely diverging; dorsal edge of the left
cardinal is fused to the margin of the shell; ventral sinus some-
what excavated; right cardinal prominent, anterior arm short, pos-
terior arm heavy, extending in a straight line from near the beak
to the ventral margin of the plate; anterior lateral short, top
evenly rounded, smooth, distant from and in alignment with the
anterior arm of the cardinal; posterior lateral long, slightly higher
than the margin of the shell arising from the ventral edge of the
hinge plate; laminae long, the ventral ones also arising from the
edges of the plate; the dorsal ones are small, arising from the

1916] Packard: Mesozoic and Cenozoic Mactrinae 291

margin of the plate. Pallial sinus deep, rounded, not extending
in front of the vertical of the beaks. The dimensions of the type
as inferred from the original cut, are: length, 45 mm., height,
35 mm.

The type of this species was collected by Townsend and de-
scribed by Conrad, together with other fossil material from a
locality on the Columbia River, near Astoria. Gabb confused this
variable species with Spisula planulata. The species was recognized
by Arnold in the Lower Etchegoin formation of the Coalinga Dis-
trict, California. Arnold’s figure of the form differs considerably
from that of the type and also from that given by Dall from the
Empire formation of Coos Bay, Oregon.

These three forms represent but three different shapes assumed
by this species. In some collecting localities these forms occur
together, while in others one form or another predominates. There
appears to be no general type found in the San Pablo group that
is not equally well represented by specimens from the Merced. A
comparison of the hinges of these different specimens shows a
remarkable uniformity as regards the dental armature.

Spisula albaria is closely related to S. albaria var. ramonensis,
from which it differs in being typically more elongate, with a nar-
rower hinge plate and shorter laterals, which are more intimately
connected with the cardinal arm. It differs from 8. selbyensis in
being more nearly equilateral, in its wider hinge plate, less com-
pressed left cardinal, shorter laminae and in the less intimate con-
nection between the anterior ventral lamina and the cardinal arm.

The type of S. precursor was obtained from the Empire Forma-
tion of Coos Bay, Oregon. The outline of this species might easily
fall within the range of the shape-variation of S. albaria. It is
therefore considered as probably representing that species.

Occurrence.—Pliocene: Merced group. Miocene: San Pablo
group.

SPISULA ALBARIA (Conrad) var. RAMONENSIS, n. var.
Plate 23, figure 5; plate 25, figures 1 and 2
Shell medium-sized, inequilateral, somewhat compressed ; height
nearly equal to that of the length; umbones rather prominent,
sharply pointed; shell smooth except for an occasional heavy incre-
mental line of growth; anterior dorsal area excavated below the

292 University of California Publications in Geology [Vou. 9

umbones; anterior dorsal edge straight; posterior dorsal edge con-
vex; sloping regularly to the broadly rounded extremity; base
arcuate. Hinge plate wide, chondophore deep, not roofed; left car-
dinal prominent, extending from the dorsal to the ventral margin
of the plate; arms of equal length, heavy, the posterior one bearing
an indistinct lamella; ventral sinus narrow; laterals long, the ante-
rior one arising from the ventral edge of the plate; it is nearly
flat-topped, and is not in alignment with, nor reaching to the
anterior arm of the cardinal. The pallial sinus, as well as the
hinge of the right valve is unknown. The dimensions of the type
are: height, 54.5 mm., convexity, 17.5 mm. Those of the cotype
are: length, 60 mm., height, 50 mm., convexity, 13 mm.

This variety is closely related to S. albaria, being perhaps the
progenitor of that species; it varies considerably as regards general
shape; elongate specimens are not separable upon the basis of shape
alone from the typical species. Since the great majority are more
ovate, and since the hinges of those specimens observed are different
from 8. albaria, it appears to be worthy of varietal rank. It differs
from Conrad’s species in that the hinge plate is relatively wider, the
left cardinal is heavier and the laterals are longer and more distant
from the cardinal arm.

Occurrence.—Oligocene: Agasoma gravidum zone, Mount Diablo
region, California.

The type of this variety was obtained from University of Cali-
fornia Locality 1687. It was collected by R. E. Dickerson, who
described the locality in the following words: ‘‘To the north of
the road leading to Tice Valley, west of the first ‘‘a’’ in ‘‘San
Ramon,’’ Concord sheet, Contra Costa County, California.

SPISULA SELBYENSIS, n. sp.
Plate 26, figures 2a, 2b and 3

Shell inequilateral, somewhat ventricose; umbones rather promi-
nent, adjacent, generally situated posterior to the middle of the
shell; area below and anterior to the beaks strongly excavated ;
anterior dorsal edge nearly straight, sloping regularly to the
broadly rounded anterior extremity; posterior dorsal edge broadly
rounded, meeting a slight truncation at the base; base arcuate;
surface marked by a varying number of incremental lines of growth ;
hinge plate very narrow; chondophore deep and somewhat com-

1916] Packard: Mesozoic and Cenozoic Mactrinae 293

pressed; left cardinal high, arms of nearly equal length, not widely
diverging; this tooth extends from the dorsal to the ventral margin
of the hinge plate; ventral sinus very restricted; laterals long, low,
round-topped, arising from the ventral margin of the plate; base
of the anterior lateral not reaching to the cardinal arm; right car-
dinal well developed, with a heavy anterior arm, which is closely
appressed to the margin of the shell; posterior arm also heavy,
reaching to the ventral border of the plate; anterior ventral lamina
long, in the same plane with, and joining the anterior cardinal arm
by a low ridge. The dimersions of the type are: length, 29 mm.,
convexity, 10 mm.

This species resembles S. albaria in general outline, but it differs
from that species in that it is generally more inequilateral and more
elongate, with a narrower hinge plate, and more compressed left
cardinal. The length of the laminae and the close relationships
between the anterior ventrai lamina and the cardinal arm also
characterize this species.

The shape of this species is exceedingly variable. The beaks
are in some specimens anterior to the middle of the shell, while in
others from the same collecting locality they are posterior to that
line. This variation has already been discussed at some length in
another portion of this paper (page 268).

The type was obtained from University of California Locality
1352. This locality was described by J. C. Merriam under number
360 as follows: ‘‘One-third of a mile south-west of Vallejo Junc-
tion, in a bluff close to the railroad track at the lowest Miocene con-
tact with the Martinez, Napa sheet.’’

Occurrence.—Miocene: Monterey group, Arca montereyana zone.

SPISULA PLANULATA (Conrad)
Plate 16, figures 3a, 3b and 3c

Mactra planulata Conrad, Jour. Acad. Nat. Sci. Phila., vol. 7, pt. 2, p. 240,
1837; (not M. planulata of Carpenter nor Standella planulatu of Gabb,
Cooper nor Stearns).28

Spisula planulata (Conrad), Conrad, Am. Jour. Conch., vol. 3, appendix,
p. 45, 1868; Dall, Nautilus, vol. 8, p. 40, 1894; Proc. Royal Soc. Canada, 2d.
ser., vol. 1, p. 48, 1894.

The general shape of this shell is somewhat like that of S. falcata,

23 These authors confused several species, notably S. albaria, S. planulata
and S. voyi, therefore their citations have but little value.

294 University of California Publications in Geology (Vou. 9

but it differs from that species in being flatter and in being more
inequilateral. If the hinges are compared, it is found that the
arms of the left cardinal of 8. planulata are of nearly equal length
whereas those of S. falcata are markedly uneven. The length of the
type is equivalent to 38 mm. The dimensions of the specimen
figured in this paper are: length, 45 mm., height, 32 mm., con-
vexity, 7 mm.

The type of this species was described from a Recent specimen
obtained from Santa Barbara, California.

Occurrence.—Recent: Monterey to San Diego, California (Dall).

SPISULA MERRIAMI, n. sp.
Plate 27, figures 3a and 4

Shell small, trigonal, equivalve nearly equilateral, ventricose,
ornamented by numerous fine concentric ridges, which are more pro-
nounced and less numerous on the anterior and posterior dorsal
areas than upon the other portions of the shell; beaks moderately
prominent, anterior dorsal area limited by a distinct ridge extending
from the umbo to the anterior extremity; the margin of this area is
nearly straight; posterior dorsal slope slightly convex, limited by an
indistinct ridge which extends from the beak to the base of the shell;
anterior extremity more sharply pointed than the posterior; base very
broadly rounded. Hinge plate relatively broad, chondophore oblique,
shallow, apically roofed by a broad flat spur; left cardinal prominent,
high, arms broad, extending from the dorsal to the ventral margin
of the plate; ventral sinus narrow, flat; right cardinal with a prom-
inent anterior arm and a well-developed, although relatively thin
posterior arm; laminae long, distant from the beaks; anterior lateral
formed from the margin of the plate, top rounding, distant from the
anterior arm of the cardinal; posterior lateral also with a rounding
top, dorsal and ventral slopes nearly equal; anterior ventral lamina
formed from the upturned edge of the hinge plate, not confluent with
the anterior cardinal arm; anterior dorsal scarcely developed, con-
siderably smaller than the corresponding posterior one. The dimen-
sions of the type are: length 18.6 mm., height 14.2 mm., convexity
4 mm.

This trigonal species might be confused with the Cretaceous
form, S. ashburnerti. It differs from that species in being less
tumid, in being more strongly sculptured and in the possession of
the posterior arm of the right cardinal.

1916] Packard: Mesozoic and Cenozoic Mactrinae 295

The type of this species was obtained from University of Cali-
fornia Locality 672. R. E. Dickerson described this station as fol-
lows: ‘‘Coalinga Quadrangle, Fresno County, California, SE 14 of
NW ¥ of Sec. 24, T 18 S, R 14 E, Parson’s Peak, in Tejon white
sandstones. About ten feet below white shale.’’

Occurrence.—Hocene: Tejon series, Parson’s Peak and the south
side of Mount Diablo, California.

SPISULA ACUTIROSTRATA, n. sp.
Text figure 2a and 0
Shell medium sized, slightly ventricose, trigonal in outline; in-
equilateral; sculptured by indistinct incremental lines of growth;
beaks prominent, strongly incurved and acutely pointed; posterior

Fig. 2. Spisula acutirostrata, n. sp. 2a, type specimen; 2b, left hinge.
Both figures natural size.

dorsal margin somewhat convex; anterior margin also shghtly con-
vex. Anterior extremity of the cotype produced and slightly trun-
cated, while the posterior end is more evenly rounded; ventral mar-
gin arcuate. Escutcheon of the type specimen impressed and broad ;
posterior dorsal area limited by a prominent angulation or ridge
which extends from the umbo to the posterior extremity. Hinge
plate rather wide; chondophore deep, quite broad; left cardinal
broken, but it was apparently low, heavy and not extending to the
ventral margin of the plate. No accessories nor spur observable.

296 Unwersity of California Publications in Geology [Vor. 9

Anterior lateral low, long; posterior lateral also rather low. Hinge
of right valve unknown. The dimensions of the type are: height,
55 mm., length, 53 mm., convexity, 17 mm.

This is the largest of the known West Coast Eocene species. It
is characterized. by its pronounced posterior ridge, its escutcheon
and its small heavy cardinal. It differs from 8. merriami, which
it superficially resembles, in its more massive cardinal, more promi-
nent posterior ridge and in the lack of pronounced ribs.

The type was obtained from University of California Locality
463. The following is the description given by R. E. Dickerson:
“SE 4 of NW \% of Sec. 32, T 10 N, R 20 W. On a branch
canon of Salt Creek, 150 feet above the bottom. Mount Pinos sheet,
California.’’

Occurrence.—Eocene: Tejon series.

SPISULA BREVIROSTRATA, n. sp.
Plate 28, figures la, 1b and 2

Shell medium-sized, compressed, equilateral, umbones small, adja-
cent; anterior dorsal edge sloping in a nearly straight line to the
rather attenuated anterior extremity. A fairly distinct ridge,
extending from the umbones to the anterior extremity, limits a
depressed area on the anterior margin of the shell; posterior dorsal
edge very slightly convex, sloping regularly to the broadly rounded
extremity; base arcuate. Hinge plate relatively wide; chondophore
very shallow, triangular in shape, probably overhung by a small
spur; left cardinal large, not overhanging the resilifer, situated ven-
trally on the hinge plate; arms of equal length, their ventral edges
rounded; laterals high, short; anterior one round-topped and shorter
than the posterior one, which is acutely pointed; dorsal base of the
anterior lateral is close to, but slightly dorsal to, the anterior arm
of the cardinal. Pallial line distant, pallial sinus reaching nearly
to the middle of the shell. Hinge of the right valve unknown. The
dimensions of the type are: length, 78 mm., height, 60 mm., con-
vexity, 15 mm.

This species has been confused with S. falcata, from which it
differs in being relatively higher and in possessing a large left car-
dinal the arms of which are of equal length.

The type of this species was collected by Bruce Martin at Uni-
versity of California Locality 1875. Martin described this station

1916] Packard: Mesozoic and Cenozoic Mactrinae 297

as follows: ‘‘Along the east bank of Eel River one mile north of
Seotia, Humboldt County, California.’’

Occurrence.—Pliocene: Wildeat group, Humboldt County, Cali-
fornia.

Subgenus Symmorphomactra Dall, 1894
Type Mactra falcata Gould

Cardinals prominent, thin, posterior arm of the cardinal tooth
overhangs the chondophore; accessories on each arm; hinge plate
flat.

SPISULA FALCATA (Gould)
Plate 26, figures la, 1b and 1c

Mactra falcata Gould, Proc. Boston Soe. Nat. Hist., vol. 3, p. 216, 1849.
Standella falcata (Gould), Gabb, Pal. Cal., vol. 2, p. 92, 1869.
Spisula falcata (Gould), Dall, Nautilus, vol. 8, p. 41, 1894.

The shell of this species is small, subtrigonal, slightly inequi-
lateral. The beaks are small, sharply pointed and situated a little
posterior to the middle of the shell; anterior dorsal edge nearly
straight; posterior edge somewhat convex; base gently arcuate;
anterior extremity somewhat attenuated, posterior evenly rounded.
Hinge plate rather wide, chondophore shallow, apically roofed and
overhung by the posterior arms of the cardinals; spur prominent;
left cardinal fragile, compressed, the anterior arm much longer
than the posterior, which markedly overhangs the resilifer; anterior
arm of the right cardinal the heavier, bearing anteriorly a small
lamella; laterals rather short, smooth, arising from the ventral
margin of the hinge plate at a point distant from the umbones;
laminae short, low and rather heavy, the dorsal ones arising from
the dorsal shell margin; a prominent lamella occurs in the left valve
between the anterior lateral and the cardinal, being parallel to and
nearly equal in height to, the latter. Pallial sinus shallow, irregu-
larly rounded. The dimensions of the specimen figured in this
paper are: length, 43 mm., height, 31 mm., convexity, 7 mm.

The Recent specimens studied show but little variation in gen-
eral shape. This species superficially resembles S. brevirostrata,
from which it has been recently separated. It differs from that new
species in being more elongate and in possessing the compressed left
cardinal characteristic of the subgenus Symmorphomactra, also in

298 University of California Publications in Geology (Vou. 9

many minor details of the hinge. It might also be mistaken for
S. planulata, from which it differs in being more ventricose and
more equilateral, besides possessing a different type of left cardinal.
The type of this species was obtained in Puget Sound.
Occurrence.—Recent: Alaska to San Diego, California (Dall).
Pleistocene: San Pedro, San Diego (Arnold). Pliocene: Etchegoin
(Arnold). Miocene: San Pablo (?) (Clark).

Subgenus Cymbophora Gabb, 1869
Type Mactra ashburnerti Gabb

Hinge heavy, resiliam with convex ends; right cardinal tooth
lacking the posterior arm; delicate, nearly at a right angle with
the anterior margin of the chondophore; left cardinal slender; lat-
erals large and robust.

SPISULA ASHBURNERII (Gabb)
Plate 26, figures 4 and 5

Mactra ashburnerii Gabb, Pal. Cal., vol. 1, p. 153, pl. 22, fig. 127, 1863;
Arnold, U. S. Geol. Surv. Bull. 396, p. 104, pl. 1, fig. 4, 1909.

Cymbophora ashburnerii (Gabb), Pal. Cal., vol. 2, p. 181, pl. 29, fig.
69, 1869.

Spisula ashburnerii (Gabb), Dall, Trans. Wagner Inst. Sci., vol. 3, pt. 4,
p. 879, 1898.

This species was described by Gabb as follows:

Shell moderate in size, subtrigonal; base broadly and regularly convex;
beaks central, slightly inclined forwards; posterior cardinal margin sloping,
straight, slightly convex; anterior faintly excavated; some specimens show
an umbonal angle well marked, while in others it is nearly or entirely
obsolete. Surface variable; specimens from some localities showing a large
number of regular, nearly uniform, rounded, concentric ribs;24 while those
found at other places have these ribs few, entirely absent, or only repre-
sented by fine lines of growth.

Hinge plate wide, chondophore spoon-shaped, shallow, with raised
margins; left cardinal slender, arms of equal length, situated medi-
ally on the hinge plate and not overhanging the pit; right cardinal
without a posterior arm, anterior one well-developed; laterals heavy,
distant from the umbones; laminae prominent, the dorsal ones
arising from the dorsal margin of the shell. The dimensions of the

24 These characters were based upon specimens afterwards recognized
as belonging to a distinct species, S. gabbiana.

1916] Packard: Mesozoic and Cenozoic Mactrinae 299

specimen figured in this paper are: length, 21 mm., height, 15.5 mm.,
convexity, 5 mm.

This species was made the basis of the genus Cymbophora, which
according to Dall should have only subgeneric value. This trigonal
species lacks the pronounced radial ribbing of the closely related
form S. gabbiana, with which it was confused by both Gabb and
Whiteaves.

The type of this species was obtained from Pence’s Ranch, Butte
County, California.

Occurrence.—Cretaceous: (?) Horsetown (Diller); common in
the upper Chico of the coast region.

SPISULA GABBIANA (Anderson)
Plate 27, figure 2
Mactra gabbiana F. M. Anderson, Proce. Cal. Acad. Sci., 3rd ser. vol. 7,
p. 74, pl. 7, fig. 156, 1902.

This species was described by Anderson as follows:

Shell moderate in size, somewhat resembling M. ashburnerii Gabb, but
generally with a heavier shell, and more strongly grooved concentrically;
umbonal angle strongly marked, especially near the base; anterior surface
flattened but not excavated.

The hinge of this species is but imperfectly known. One speci-
men from Chico Creek, California, which undoubtedly belongs to
this species shows a well-developed anterior arm to the right ear-
dinal, but no trace of a posterior arm. Another specimen of the
left valve has a rather shallow chondophore bounded by raised
margins, characteristic of the subgenus Cymbophora. The cardinal
is prominent, massive, extending ventrally nearly across the hinge
plate; the arms are very thick; anterior lateral apparently fused
to the dorsal side of the anterior arm of the cardinal; posterior lat-
eral long, but little higher than the adjacent shell margin. Palhal
sinus rather shallow, broadly rounded. Its dimensions, as meas-
ured upon the figure of the type are: length, 44 mm., height, 33 mm.

This species differs from S. ashburnerw in being typically much
larger and more heavily ribbed and less angulated posteriorly.

The type of this species was obtained from Henley Creek, Sis-
kiyou County, California.

Occurrence.—Cretaceous: Chico of Henley Creek, Chico Creek
and numerous other Chico localities of California.

300 University of California Publications in Geology [Vou. 9

SPISULA CHICOENSIS, new name
Plate 27, figures 6 and 7

Lutraria truncata Gabb, Pal. Cal., vol. 1, p. 154, pl. 22, fig. 128, 1863.
Spisula truncata (Gabb), Dall, Trans. Wagner Inst. Sci., vol. 3, pt. 4,
p. 879, 1898.

This species was described by Gabb as follows:

Shell thin, compressed, somewhat elongated, length compares with the
breadth as about four to three; beaks nearly central, small, acute and
slightly inclined forwards; anterior cardinal margin slightly sinuous, pos-
terior convex, nearly straight; anterior end rounded; posterior obliquely
truncated, gaping. Surface marked by faint irregular lines of growth.

Only part of the hinge of the left valve is known. Hinge plate
wide, resilifer very narrow, long, with raised margins, which appear
aS a prominent toothlike ridge arising from the posterior margin
of the chondophore; resilifer not roofed nor overhung by the
cardinal arm; cardinal very prominent, high, arms of equal length,
extending nearly across the hinge plate; ventral sinus excavated;
anterior lateral partially destroyed; it is high and arises from the
ventral margin of the plate, extending nearly to the dorsal margin
of the shell, at some distance from the arm of the cardinal; posterior
lateral short, nearly parallel to the ridge bounding the chondophore.
Pallial sinus unknown. The dimensions, as inferred from the figure
of the type are: length, 50 mm., height, 35 mm. A specimen from
the type locality measures: length, 49 mm., height, 36 mm., con-
vexity, 8 mm.

Spisula chicoensis is quite constant in general shape, which
strongly suggests that of a Tellina. This form would not easily be
confused with any known coast Mactrinae.

The specific name truncata was used by Montagu in 1808 for a
species that later became known as Hemimactra truncata:*? It is
necessary to rename Gabb’s species, because the genus Hemuimactra
has since been reduced to the rank of a subgenus under Sprsula.

This species was described from specimens obtained from Pence’s
ranch, (Pentz Post Office) Butte County, California.

Occurrence.—Cretaceous: Chico, Pence’s ranch, Chico Creek, and
Mineral Slide, Butte County, California (Gabb).

25 Conrad, T. A., Am. Jour. Conch., vol. 3, appendix, p. 33, 1868.

1916] Packard: Mesozoic and Cenozoic Mactrinae 301

SUBGENERIC Posirion UNCERTAIN
SPISULA CALLISTAEFORMIS Dall

Spisula callistaeformis Dall, Harriman Ala. Exped., vol. 4, p. 108, pl. 9,
fig. 9, 1904.

Dall described this species as follows:

Shell elongate, recalling Macrocallista in outline, the anterior end slightly
shorter, attenuated in front, arcuate below, wider and rounded behind with
an obscure radial ridg2 near the dorsal slope; disk slightly flattened, con-
centrically striated, the beaks pointed and moderately elevated. . . . This
species is rather abundant and uniform. The pallial sinus is deep and
free from the pallial line for most of its length below. The dimensions
of the holotype specimen are: length, 50 mm., height, 28 mm., con-
vexity, 8 mm.

This species is based upcn fossil specimens obtained from the
eastern side of Chichagof Cove, Alaska. The holotype was depos-
ited in the United States National Museum under the catalogue num-
ber 164882.

Dall suggests that this species may belong to the subgenus Cym-
bophora. Specimens of this species have not been available for
study and therefore its subgeneric position is still uncertain.

Occurrence.—Eocene: Upper Stepovak series, Alaska (Dall).

SPISULA COALINGENSIS (Arnold)
Plate 27, figure 8
Mactra coalingensis Arnoid, U. S. Geol. Surv. Bull. 396, p. 71, pl. 25,
fig. 4, 1909.

This species was described by Arnold as follows:

Shell averaging about 52 millimeters in width, equivalve, trigonal in
outline, rounded behind, slightly attenuated in front; beaks not prominent,
situated slightly anterior to middle of shell; anterior superior margin only
slightly excavated in frent of beaks, nearly straight to anterior extremity,
which is quite abruptly truncated; posterior inferior margin slightly curved,
and merging imperceptibly into the regularly convex posterior extremity;
basal margin moderately curved. Hinge and cartilage areas concealed in
the type, but believed to be similar to M. falcata Gould. The dimensions
of the type are: length, 65 mm., height, 52 mm,

Although several specimens that agree with the above deserip-
tion have been collected from the Etchegoin of the Coalinga District,
none has been found that shows the hinge. The general shape and

302 University of California Publications in Geology [Vou. 9

its possible affinities with S. falcata are the bases for the change of
genus as given above.

This species is larger, relatively broader and more trigonal than
S. faleata. It differs from S. brevirostrata in being more nearly
equilateral and from S. albaria in being less ventricose.

The type of this species was obtained in Waltham Creek Valley,
south of Coalinga, Fresno County, California. It was deposited in
the United States National Museum under the catalogue number
1655138.

Occurrence.—Pliocene: Etchegoin formation, Coalinga District,
California (Arnold).

SPISULA LENTICULARIS (Gabb)

Hemimactra lenticularis Gabb, Pal. Cal., vol. 2, p. 19, pl. 4, fig. 3, 1869.

This species was described by Gabb as follows:

Shell large, flattened, thin, inequilateral, irregularly subquadrate; beaks
eccentric, large, slightly curved forwards and inwards; anterior end broadly
concave below the beaks and convex below; base and posterior end regu-
larly convex; cardinal margin sloping nearly straight. Hinge teeth slender.
Pallial sinus moderately deep, round at the base. Surface marked by irregu-
lar lines of growth. The dimensions of the type are equivalent to: length,
96 mm., height, 106 mm., convexity, 22.8 mm,

The type of this species is apparently lost. The form will be
listed as a NSpisula, since the genus Hemimactra as used by Gabb
has been reduced to the rank of a subgenus. Fragments of a large
form which may be referable to this species, have been collected
from the region of the type locality.

The type locality of this species is given as ‘‘South of Martinez,
Contra Costa County California.”’

Occurrence.—Miocene: Contra Costa County, California (Gabb).

SPISULA SISQUOCENSIS Arnold
Spisula sisquocensis Arnold, Smithsonian Misc. Coll., vol. 50, p. 437,
pl. 56, fig. 1, 1907.
This species was described by Arnold as follows:

Shell averaging about 120 millimeters in longitude, subtrigonal in outline,
equivalve, inequilateral, ventricose; base regularly arcuate; beaks anterior,
prominent, bent forward, protruding beyond periphery of shell; anterior

1916] Packard: Mesozoic and Cenozoic Mactrinae 303

end shorter and narrower than the posterior, which is evenly rounded;
area in front of beaks depressed concavely as a whole, but slightly elevated
at margin, this condition when the two valves are together, suggesting a
large lunule with a slightly raised ridge running down the middle; pos-
terior margin becomes more and more arcuate as extremity is approached,
sculpture consisting of numerous fine incremental lines, some of which are
more prominent than the great majority, these more prominent ones giving
a slightly irregular surface to the shell. Hinge and intericr unknown,
but probably quite similar to S. hemphillii. The dimensions of the type
are given as: length, 120 mm., height, 85 mm., convexity, 28.5 mm.

This species was found associated with S. catilliformis var. alca-
trazensis Arnold. Specimens of this species have not been available
for study, therefore its subgeneric relationships cannot be stated.

The type of this species was obtained from the Fernando forma-
tion from the Alcatraz asphalt mine, near Sisquoc, Santa Barbara
County, California. It was deposited in the United States National
Museum under catalogue number 165292.

Occurrence.—Pliocene: Fernando formation (Arnold).

SPISULA TEJONENSIS, n. sp.
Plate 27, figure 5

Shell small, elongate, equivalve and nearly equilateral; umbones
not prominent, adjacent; anterior dorsal edge slightly concave imme-
diately under the beaks, but then becoming straighter until the
rather arcuate anterior extremity is reached; posterior dorsal edge
slightly convex; posterior extremity a little more rounded than the
anterior; base broadly and evenly rounded; dorsal area limited by
an indistinct umbonal ridge, extending from the beaks to the pos-
terior extremity of the shell; this posterior dorsal area is marked
by fine regularly disposed concentric ridges, which do not typically
extend beyond the slightly carinated umbonal ridge. Interior un-
known. The dimensions of the type are: length, 22.5 mm., height,
16.5 mm., convexity, 6 mm.

It was with some hesitation that this form was described without
first studying the hinge. Its distinctive shape and its frequent oc-
currence in the California Eocene appear to justify the naming of
this form.

This species is distinguished from 8. merriami by its less ventri-
cose and more elongate shape, together with its less pronounced con-

centric sculpture.
The type of this species was obtained at University of California

304 University of California Publications in Geology [Vou. 9

Locality 785, which is described by R. E. Dickerson as follows:
‘‘Vicinity of Lower Lake, Lake County, Tejon Group. NW 14 of
SE 14 of Sec. 6, T 13 N, R 6 W, in a west gully near hill top. Ele-
vation 1750 feet.’’

Occurrence.—Eocene: Tejon group, Lower Lake and Mount
Diablo, California.

Genus Muuinia Gray, 1837
Type Mactra typica Gray

Ligament and resilium not separated, entirely internal; teeth
not concentrated ; laterals subequal; valves not gaping. Pallial sinus
small and short.

MULINIA DENSATA Conrad
Plates 29, 30, 31, 32 and 33

Mulinia densata Conrad, Proc. Acad. Nat. Sci. Phil., December 1856,
p. 313; Pacific R. R. Repts., vol. 6, p. 71, pl. 3, fig. 12, 1857; Gabb, Pal.
Cal., vol. 2, p. 19, pl. 5, fig. 35, 1869 (in part); Arnold, U. S. Geol. Surv.
Bull. 396, p. 55, pl. 21, fig. 3, 1909.

Cardium gabbii Rémend, Proc. Cal. Acad. Sci., vol. 3, p. 13, 1863.

Pseudocardium gabbii (Rémond), Gabb, Pal. Cal., vol. 2, p. 21, pl. 6,
figs. 45a, b and c, 1869.

Mulinia oregonensis Dall, U. S. Geol. Surv. Prof. Paper 59, p. 132, pl. 9,
figs. 2 and 3 and pl. 13, fig. 5, 1909.

This species was described by Conrad as follows:

Subovate, ventricose, thick, very inequilateral; posterior side very short
comparatively, contracted; extremity subtruncated, much above the line
of the base; posterior basal margin very oblique and contracted; anterior
end obliquely truncated; anterior basal margin rounded; summits promi-
nent, distant; external teeth very robust and prominent; inner margin
entire. The length of the type is equivalent to 73 mm. The height as
measured on the original figure is 58 mm.

Conrad’s original description of Mulinia densata was supple-
mented by a figure which was later criticized by Gabb, who con-
tended that the species was based upon a contorted specimen. Gabb
redescribed the species, basing his description upon a specimen ob-
tained from near San Pablo Bay, California. He appeared to base
his conclusions upon the general shape of the shell, for he failed to
note that Conrad’s species was described as having ‘‘very robust

1916] Packard: Mesozoic. and Cenozoic Mactrinae 305

2

and prominent teeth,’’ whereas his San Pablo specimen had a small
hinge with slender teeth.

Rémond described a form from the Miocene of Walnut Creek,
Contra Costa County, California, under the name of Cardium gabbii,
which later served as the type of Gabb’s genus Pseudocardium.
Arnold, after making a study of the forms from the Coalinga Dis-
trict, California, came to the conclusion that Pseudocardium gabbii
and Mulinia densata were identical. He also described a form from
the Vaqueros under the name of M. densata var. minor.

Another form was described from the Empire formation of Coos
Bay, Oregon, under the name of Mulinia oregonensis Dall. This is
based largely upon the rugose character of the shell and its narrow
shape. Both of these characters fall within the range of variation
of M. densata.

Related forms were reported from the Miocene of Washington.
One was given specific rank while the others were listed as varieties
of Pseudocardium gabbu. The types of these four forms have
been studied and their relationships may now be more clearly shown.

Specimens representing these different forms from a large num-
ber of localities have been studied from the standpoint of the gen-
eral shape and from that of the dental armature. The conclusions
of these studies are that these species and varieties as given above
in the synonymy are not separable into distinct species or even
varieties. The extremes in a suite from one collecting locality or
series made up of specimens from different localities and horizons
are often markedly different, but an attempt to so define the
extremes in terms that will serve to separate the middle members
has been unsuccessful.

The figures show a few picked specimens of series showing the
relative prominence of the umbones, (plate 25), the general shapes,
(plate 26) and the characters of the dentition (plate 28). Plate 26
shows the amount of variation commonly found in the more ventri-
cose forms. This series represents specimens from a single collect-
ing locality, showing how the short tumid form grades into the
elongate flat type. Specimens that appear to have lived under
adverse conditions are shown on plate 27. The narrow, crude valves
of this series are not distinguishable from Mulinia oregonensis of
Dall, which is here considered synonymous with M. densata.

Not only are there shape gradations between the typical and

306 University of California Publications in Geology [Vou. 9

the Pseudocardium form, but the hinges of the two are to all essen-
tials identical.

The differences of the hinge of the left valve, as figured on plate
29 are those of varying thicknesses of the laterals and the arms of
the cardinals. This thickening appears to be a function of the
shortening of the hinge line of the more ventricose forms. These
dental characters grade insensibly along with the changing shape of
the shell from that of the elongate typical form with its long laterals
to the Pseudocardium form with its robust teeth.

It is worthy of mention that in the region of Mount Diablo,
California, the great majority of specimens belong to the ventricose
type, whereas at a higher horizon in the Coalinga District these
Pseudocardium forms are the exception. This might suggest that
these two forms represent two parallel races, one of which became
dominant during the San Pablo, while the typical form reached its
maximum in the Etchegoin; and that they did not diverge enough
from the parent stock to be easily classified as definite species.

The hinge plate of Mulinia densata is rather wide; chondophore
deep; roofed apically and overhung by a lamella in the left valve;
the left cardinal prominent, often heavy, the arms of equal width,
and often fused together in the Pseudocardium forms, producing a
triangular block-tooth and varying in this respect to a condition
where the arms are clearly defined; the arms of the cardinal reach
ventrally nearly across the hinge plate; the anterior arm of the
right cardinal is more prominent than the posterior one; laterals of
unequal length; distant from the beaks, being relatively short and
heavy in the more ventricose forms; anterior lateral nearly in align-
ment with the cardinal arm, but distant from that tooth; laminae
heavy, the anterior ventral one is in line with the cardinal arm;
dorsal laminae small, arising from the dorsal margin of the shell.
Pallial sinus shallow, broadly rounded. Mulinia densata is separable
from M. pabloensis by the lack of striations on the lateral teeth ; from
M. alta by its much heavier left cardinal and wider hinge plate;
and from M. wndilifera by its narrower hinge plate and more deli-
eate teeth.

Conrad’s type was obtained from the vicinity of Santa Bar-
bara, California.

Occurrence.—Pliocene: Etchegoin. Miocene: San Pablo, Upper

Monterey.

1916] Packard: Mesozoic and Cenozoic Mactrinae 307

MULINIA DENSATA Conrad var. MINOR Arnold

Mulinia densata, var. minor Arnold, U. S. Geol. Surv. Bull. 396, p. 54,
pl. 5, fig. 6, 1909.

This variety is characterized by its smaller size, and its more
inequilateral form than the typical M. densata. Its hinge is un-
known.

The type of this variety was obtained from Jasper Creek, Fresno
County, California. It was deposited in the United States National
Museum under catalogue number 165601. The dimensions as meas-
ured on the original figure are: length, 42 mm., height, 36 mm.

Occurrence —Pliocene: Etchgoin (Arnold). Miocene: Vaqueros
(Arnold).

MULINIA ALTA (Weaver)

Pseudocardiuwm gabbi (Rémond) var. altum Weaver, Wash. State Geol.
Surv., Bull. 15, p. 68, pl. 7, fig. 69, 1912.

P. gabbi, var. elongatum Weaver, op. cit., p. 68, pl. 10, fig. 78.

P. gabbi, var. robustum Weaver, op. cit., p. 69, pl. 7, fig. 68.

This variety was described by Weaver as follows:

This variety is large, somewhat compressed; beaks moderately high but
not especially prominent for the genus. Anterior and posterior margins
have steep slopes, the latter being more pronounced. The altitude is much
greater in proportion to the longitude than in the case of the other varieties.
The dimensions of the type are: length, 75 mm., height, 78 mm., con-
vexity, 30 mm.

The type specimens of Pseudocardium gabbu var. altuwm, P. gabbi
var. elongatum and P. gabbui var. robustuwm were kindly loaned the
writer by Dr. C. E. Weaver of the University of Washington.

The hinges of these three type specimens have been exposed and
their relationships may now be definitely stated. A comparison
with typical specimens of Mulinia densata from California show
that, although the general shape of these Washington forms falls
within the range of the variation of the typical species, the dental
armature possesses differences of at least varietal value.

The shapes of the three forms are somewhat different, but the
hinges are nearly identical, varying only as one individual varies
from another. The three specimens show the left cardinals, two of
them show the anterior lateral but in none of them is the posterior

lateral preserved.

308 University of California Publications in Geology (Vou. 9

The hinge plate is narrow, the chondophore deep, oval, apically
roofed, not overhung by an accessory; cardinal tooth very small,
high, situated medially on the hinge plate, arms of equal length,
thick, anterior lateral long, low, reaching nearly to the arm of the
cardinal. Hinge of the right valve and the pallial sinus unknown.

This species differs from Mulinia densata in its narrower hinge
plate and much smaller cardinal tooth. It is separable from Mulinia
pabloensis by the absence of striations on the lateral teeth, and
from M. undilifera by its much more delicate teeth.

The type of this variety was obtained from Miocene strata near
Elmer, Chehalis County, Washington.

Occurrence.—Miocene: Upper Miocene, Elmer, and Satsop, Che-
halis County, Washington (Weaver).

MULINIA UNDILIFERA (Weaver)
Plate 34, figures la, 1b, 2 and 3

Pseudocardium gabbi (Rémond) var. undiliferum Weaver, Wash. State
Geol. Surv. Bull. 15, p. 69, pl. 9, fig. 76, 1912.

This variety was described by Weaver as follows:

Shell typically small, anterior margin slightly convex with a slope of
60°; posterior margin nearly straight with a slope of 45°; posterior surface
of the shell undulatory because of broad groove extending from the beak
to the margin. These characters are constant and do not seem to grade
into the other varieties. Several hundred specimens from the same locality
show these characteristics. The dimensions of the type are: length, 50 mm.,
height, 40 mm., convexity, 20 mm.

The hinge of this species as shown on the type and plesiotype
is very heavy, the hinge plate very wide and thick; chondophore
deep, roofed, but apparently not overhung by an accessory; the
left cardinal is partially worn so its height is unknown; the arms
are of equal length, extending ventrally nearly across the hinge
plate; right cardinal not clearly shown in the specimens, the ante-
rior arm was probably rather inconspicuous, posterior arm repre-
sented by a heavy basal ridge; laterals smooth, very robust, low;
the anterior one extends for a short distance dorsal to the cardinal
arm; laminae low, the dorsal ones formed entirely from the thick-
ened dorsal margin of the shell and not represented by a distinct
tooth. The hinge plate at the ventral ends of the laterals is sharply

truncated.

1916] Packard: Mesozoic and Cenozoic Mactrinae 309

The general shape is stated to be quite constant, especially as
regards the posterior flexure. The hinge of the few specimens
observed seem quite constant and sufficiently different from any
other species or variety to deserve specific rank.

This species might be confused with M. densata or M. alta, but
it is readily separable from either of these upon the basis of its
unique type of dorsal laminae and its robust laterals.

The type of this species was obtained from Sylvia Creek, Che-
halis County, Washington.

Occurrence.—Miocene: Upper Miocene of Sylvia Creek, Chehalis
County, Washington (Weaver).

MULINIA LANDESI (Weaver)

Pseudocardium landesi Weaver, Wash. State Geol. Surv. Bull. 15, p. 69,
pl. 9, fig. 75, 1912.

This species was described by Weaver as follows:

Shell thick, equivalve. nearly equilateral; anterior and posterior margins
sloping steeply and at about the same angle; base evenly rounded; beaks
prominent and pointing slightly forwards; escutcheon narrow but fairly
well defined. Surface ornamented with heavy concentric lines of growth;
hinge moderately heavy. The dimensions of the type are: length, 45 mm.,
height, 53 mm., convexity, 25 mm.

The writer has not seen the type of this species. It comes from
the same collecting locality as did the species M. undilifera and it
may represent but a ventricose form of that variety.

The type of this species was obtained from Sylvia Creek, Che-
halis County, Washington.

Occurrence.—Miocene: Upper Miocene of Sylvia Creek, Chehalis
County, Washington (Weaver).

MULINIA PABLOENSIS, n. sp.
Plate 34, figures 4a and 4b
Shell rather ventricose, nearly equilateral, wnbones usually pos-
terior to the middle of the shell; anterior dorsal edge nearly straight,
excavated in front of the beaks; anterior extremity rounded to sub-
truncate; posterior dorsal edge slightly convex, extremity strongly
truncated ; some specimens show a posterior umbonal ridge, which is
imperfectly seen in the type; base broadly arcuate. Surface rough-
ened by numerous irregular lines of growth. Pallial sinus shallow ;

310 University of California Publications in Geology — [Vou. 9

other muscle scars deeply impressed. The hinge of the type lacks
the posterior laminae and the posterior arm of the cardinal. Hinge
plate rather heavy, chondophore relatively shallow, roofed; right
cardinal with a small anterior arm which is closely appressed to the
dorsal margin of the shell; anterior laminae long, strongly striated
on their inner sides, the dorsal one being nearly as long as the
ventral one, and arising as a long thin tooth, from the hinge plate
to a height greater than that of the adjacent shell margin. In
one specimen the ventral lamina is rather heavy and_ distinetly
striated, not confluent with the anterior arm of the cardinal. The
cotype shows the left valve with a rather small but prominent car-
dinal and large striated laterals, which are distant from the um-
bones, the anterior one not reaching to the cardinal arm. The
dimensions of the type are: height, 48 mm., convexity, 18 mm.
Those of the cotype are: length, 54 mm., height, 48 mm., convexity,
36 mm.

This species is extremely variable in general shape, paralleling
in many respects the forms assumed by Mulinia densata. It differs
from all mulinoid species of the Coast region in the striated char-
acter of its laterals and laminae.

The type was obtained at University of California Locality 1946,
which was described by J. P. Buwalda in the following words:
‘“About 150 feet slope distance up the south-west side of the high-
est hill north-east of Joe Mendosa’s house, which is about one-half
mile south-west of Shell Ridge, Concord Sheet, Contra Costa County,
California.”’

Occurrence.—Miocene: Upper Monterey to Upper San Pablo.
Found at a number of localities in the region of Mount Diablo,

California.

GENERIC Position UNCERTAIN
MACTRA(?) GIBBSANA Meek

Mactra gibbsana Meek, Proc. Phila. Acad. Nat. Sci., vol. 13, p. 315,
1861; Bull. U. S. Geol. and Geog. Surv. Terr., vol. 2, no. 4, p. 374, pl. 2,
figs. 8, 8a and 8b, 1876.

Meek described this species as follows:

Shell transversely oval, or subtrigonal, moderately convex, rather thin;
anterior side narrowly rounded; base forming a regular semielliptical curve;
posterior side slightly truncated at the immediate extremity, abruptly

1916] Packard: Mesozoic and Cenozoic Mactrinae 311

rounded or subangular at its connection with the base below; dorsal out-
line sloping from the beaks in front and behind, at an angle of 120°;
beaks central, rather elevated, but small, and not projecting much above
the hinge margin; surface marked only by moderately distinct lines of
growth. Posterior muscular impression oval, well-defined; pallial line dis-
tinct, and provided with a rather deep, horizontal sinus, about one-third
longer than wide. The type specimen had the following dimensions:
length, 55 mm., height, 41 mm., convexity, 12 mm.

The type of this species was obtained from a piece of float found
on the shore of the Straits of Juan de Fuca.

Occurrence.—Cretaceous (?); Straits of Juan de Fuca (Meek).

MACTRA(?) MONTEREYANA Arnold

Mactra monteryana Arnold, Proc. U. 8. Nat. Mus., vol. 34, p. 381, pl. 35, fig.
2, 1908; U. S. Geol. Surv. folio 1638, pl. 35, fig. 2, 1909.

Arnold described this species as follows:

Shell attaining a length of at least 30 mm.; width a little more than one-
half length, subtrigonal, compressed, subequivalve, inequilateral; umbones a
little behind middle, small, turned slightly forward; anterior margin consid-
erably longer than posterior; very gently convex; anterior eytremity quite
sharply angulated below; a faintly developed carina or angle, most promi-
nent near umbo, extends from the latter to the anterior extremity; base only
very slightly rounded; posterior dorsal margin nearly straight, sloping only
moderately steeply; posterior extremity regularly rounded and situated
nearly midway between base and umbo; surface sculptured by numerous fine
incremental lines and numerous obsolete short undulations. The dimensions
of the type are: length, 31 mm., height, 18 mm., convexity, 2 mm.

This form has not been recognized by the writer. Its generic
position is uncertain, but judging from the cut and the description,
it is more likely to be a Spisula than a Mactra.

This species was described from a fossil specimen obtained from
the Monterey shales on Love Creek, Santa Cruz County, California.
The type is in the United States National Museum under catalogue
number 165463.

Occurrence.—Miocene: Monterey group, Santa Cruz Mountains,
California (Arnold).

MACTRA(?) STANTONIT Arnold

Mactra stantoni Arnold, Proc. U. S. Nat. Mus., vol. 34, p. 357, pl. 31, fig. 3,
1908.

312 University of California Publications in Geology [Vou. 9

This species was described by Arnold as follows:

Shell averaging from 40 to 50 mm. in length, subtrigonal in outline, alti-
tude about five-sevenths of length, equivalve, equilateral, the beaks located
midway, the shell moderately thin, moderately convex. Anterior margin only
very slightly depressed in front of beaks; quite evenly but somewhat acutely
rounded in front; base evenly rounded; posterior extremity not quite as
attenuated as anterior; a faint suggestion of an angle or carina extends from
the beak to the posterior extremity. Surface sculptured by numerous small
but sharply defined quite regular concentric ridges, separated by interspaces
somewhat narrower than the latter, also by fine incremental lines which
appear more prominent where the concentric ridges are obsolete. Hinge only
moderately strong, umbonal pit small; lateral teeth high and thin, extending
above the adjacent margins of the shell. Interior unknown. The dimensions
of the type are: length, 50 mm., height, 34 mm., convexity, 12 mm.

This species has not been available for study, therefore its defi-
nite relationships are unknown.

The type of this species was obtained from the Chico series at
Pigeon Point, San Mateo County, California. It was deposited in
the United States National Museum under catalogue number 31001.

Occurrence.—Cretaceous: Chico series, Pigeon Point, San Mateo
County, California (Arnold).

MACTRA(?) TENUISSIMA Gabb

Mactra tenuissima Gabb, Pal. Cal., vol. 2, p. 179, pl. 29, fig. 68, 1869.

Gabb described this species as follows:

Shell small, extremely thin, subequilateral; beaks central, small, pointed
slightly in advance; anterior end obliquely and convexly subtruncated; base
regularly convex. Surface marked by minute, concentric striae of growth; an
angulated ridge runs from the umbones to the posterior basal angle. Pallial
sinus deep and narrow. The dimensions of the type as given by Gabb are
equivalent to: length, 27.9 mm., height, 19.3 mm., and convexity, 3.8 mm.

This form has been reported from the Martinez group of Lake
County by Dickerson.?* The specimens upon which his determina-
tions are based do not reveal the generic characters of the form. It
must therefore be listed as a questionable mactrine species.

Occurrence.—Kocene: Martinez group (Dickerson).

26 Dickerson, R. E., Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, p. 96, 1914.

1916] Packard: Mesozoic and Cenozoic Mactrinae hls:
SPISULA(?) WEAVERI Packard
Plate 27, figure 9

Spisula (?) weaveri Packard, Dickerson, Univ. Calif. Publ. Bull. Dept.
Geol., vol. 8, p. 139, pl. 12, figs. 4a, 4b, 1914.

Packard deseribed this species as follows:

Shell small, relatively thick, subtrigonal to oval, moderately ventricose,
evenly rounded; umbones nearly central, prosogyrate, prominent, nearly
adjacent; anterior dorsal margin concave for a distance equal to about one-
third the height of the shell; anterior extremity slightly attenuated, evenly
rounded; base broadly rounded, curving gently in the dorsal region to the
beak; surface roughened by coarse lines of growth; hinge and interior but
imperfectly known. The dimensions of the type are: length, 32 mm., height,
26 mm., convexity, 5 mm.

There is considerable variation in the outlines of this species.
A specimen doubtfully compared to this species was noted in the
collections of the Scripps Institution for Biological Research from
the Tejon of Rose Canon, San Diego County. It clearly shows the
impressions of a spisuloid dentition.

The type was obtained from the Martinez near Stewartville,
Contra Costa County, at University of California Locality 1556,
which may be described as follows: NE 4% of NW % of See. 15, T
1 N, R 1 &, a little over one mile south of Stewartville, ten feet
above the Martinez Chico contact.

Occurrence—EKocene: Lower Martinez, Mount Diablo region,

California.

Species Not VAuip

MACTRA(?) GABIOTENSIS Conrad

7

Mactra(2) gabiotensis Conrad, Pac. R. R. Reports, vol. 7, p. 194, pl. 7,
fig. 3, 1854-55.

The description of this species was based upon a cast of a fossil
specimen obtained from Gaviota Pass, California. Its general out-
line is comparable to several Miocene mactrine species and_there-
fore it must be declared an invalid species.

EXPLANATION OF PLATE 12

Fig. la. Mactra stultora Linnaeus. x 1.
Interior of the left valve of the typical species of the genus
Mactra. Foreign, Recent,

Fig. 1b. Mactra stultora Linnaeus. x1. Foreign, Recent.
Fig. 2a. Mactra nasuta Gould. x1. Recent.

Fig. 2b. Mactra nasuta Gould. x 1. Recent.

Fig. 2c. Mactra nasuta Gould. x1. Recent.

Fig. 3a. Mactra dolabriformis (Conrad). x 2. Recent.
Fig. 3b. Mactra dolabriformis (Gould). x 2. Recent.
Fig. 3c. Mactra dolabriformis (Conrad). x 2. Recent.
Fig. 4a. Mactra exoleta Gray. x1. Pleistocene.

Fig. 4b. Mactra exoleta Gray. x1. Pleistocene,

[314]

WINIMICAEIFS RUBE. BUILE, DERI. GEOL. [PACKARD] VOL. 9, PL. 12

.
‘
‘
: = <f
+ 7 eriees! -

ig. la.

EXPLANATION OF PLATE 13

All figures natural size.

Spisula solidissima Dilliwyn. Atlantic Coast, Recent.

The type of the subgenus Hemimactra.
Spisula solidissima Dilliwyn. Atlantic Coast, Recent.
Mactra exoleta Gray. Pleistocene.

Mactra trampasensis, n. sp. Miocene.
Umbonal view.

Spisula voyi (Gabb). Pliocene.
Probably Gabb’s type.

[316]

ation

UNIV CALIER PUBL: BULL.DERT, GEOL,

[PACKARD] VOL. 9, PL.

13

EXPLANATION OF PLATE 14
All figures natural size.

Fig. 1. Spisula voyi (Gabb). Recent.
Fig. 2. Spisula voyi (Gabb). Recent.

[318]

UNIMeG CALIE., IRUBES BUELL. DEPT GEOE: [PACKARD] VOL. 9, PL. 14

EXPLANATION OF PLATE 15

All figures natural size.

. la. Spisula voyi (Gabb). Pliocene.
. 1b. Spisula voyi (Gabb). Pliocene.
. 2. Spisula voyi (Gabb). Pliocene.

[320]

WINIV. «CALIF. PUBL. IBULEE. DEPT. GEOL, [PACKARD] VOL. 9, PL. 15

EXPLANATION OF PLATE 16

Mactra trampasensis, n. sp. x 1%. Miocene,
Fragment of left hinge, showing the cardinal.

Mactra trampasensis, n. sp. xX 1. Miocene.
Spisula planulata (Conrad). x1. Recent.

Spisula planulata (Conrad). x1. Recent.

Spisula planulata (Conrad). x 1. Recent.

Mactra californica Conrad. x 2. Recent.

Mactra californica Conrad. x 2. Recent.

Mactra californica Conrad. * 2. Recent.
[322]

UNIV. CALIF, PUBL. BULL. DEPT. GEOL. [PACKARD] VOL, 9, PL. 16

—

EXPLANATION OF PLATE 17
Natural size.

Spisula catilliformis Conrad. Recent.

[324]

UNIV. CALIF, PUBL. BULL, DEPT. GEOL, [PACKARD] VOL. 9, PL. 17

EXPLANATION OF PLATE 18
Both figures natural size.

Fig. 1. Spisula catillifermis Conrad. Recent.
Left hinge of a young specimen.

Fig. 2. Spisula catilliformis Conrad. Recent.

ey
“=

UNIV. CALIF. PUBL. BULL. DEPT. GEOL, [PACKARD] VOL. 9, PL. 18

ig. la.

5 Alfa).

EXPLANATION OF PLATE 19
All figures natural size.

Spisula catillifermis Conrad. Miocene.
Hinge of the left valve.

Spisula catilliformis Conrad. Miocene.

Spisula catilliformis Conrad. Recent.
Right hinge of a young specimen.

[328]

UNIV] CAEIE. PUBE. BUELL. DERI; GEOL, [PACKARD] VOL. 9, PL. 19

\
|
|

EXPLANATION OF PLATE 20
Both figures natural size. .

Fig. la. Spisula mercedensis, n. sp. Pliocene.

Fig. 1b. Spisula mercedensis,n.sp. Pliocene.
Left hinge of the type. ;

UNIV. CALIF. PUBL. BULL. DEPT, GEOL, [PACKARD] VOL, 9, PL, 20

.
,
: 7 Fe = i
2 “, a 4

EXPLANATION OF PLATE 21
Natural size.

Spisula hemphillii (Dall). Recent.

Fale 2a

2,

[PACKARD] VOL.

CAGE UBL BUERM DER Ic GEOL,

UNIV.

EXPLANATION OF PLATE 22
Natural size.

Spisula hemphillii (Dall). Recent.

VINIVeCAEIR PUBL. IBUIEE. (DEPT. GEOL, [PACKAR DI! VOL, ‘9; Ri. 22

Fig.
Fig.
Fig.
Fig.

Fig.

ae Oe

EXPLANATION OF PLATE 23
All figures natural size.
Spisula occidentalis (Gabb). Miocene.
Spisula occidentalis (Gabb). Miocene.
Spisula occidentalis (Gabb). Miocene.

Spisula abscissa (Gabb). Miocene.
Left hinge.

Spisula albaria (Conrad), var. ranonensis, n. var.
Hinge of left valve of cotype.

[336]

Miocene,

UNIV (CARIE: PUBED IBUELY DEPT: “GEOL, [PACKARD] VOL. 9, PL. 23

a eee

EXPLANATION OF PLATE 24
Both figures natural size.

Fig. 1. Spisulaalbaria (Conrad). Miocene.

Fig. 2. Spisula abscissa (Gabb). Miocene.

[338]

WNIV CARIE: (RUBLE, BULL. DEPT. GEOL. [PACKARD] VOL. 9, PL. 24

bo

2 gt

v

EXPLANATION OF PLATE 25

All figures natural size.

Spisula albaria (Conrad) var. ramonensis, n. var.

Hinge of type.

Spisula albaria (Conrad) var. ramonensis, n. var.

Spisula albaria (Conrad). Pliocene.
Fragment of left hinge.

Spisula albaria (Conrad). Pliocene.
Showing the right cardinal.
Spisula albaria (Conrad). Pliocene.
Spisula albaria (Conrad). Pliocene.
Spisula albaria (Conrad). Pliocene.

Spisula albaria (Conrad). Miocene.

[340]

Miocene.

Miocene.

UNIV. CALIF. PUBL, IBULL..DEPT. GEOL, [PACKARD] VOL. 9, PL. 25

EXPLANATION OF PLATE 26

Spisula falcata (Gould). x 1.

Spisula falcata (Gould). x 1.

Spisula falcata (Gould). x 1.

Spisula selbyensis, n. sp. xX 2.

Right hinge.

Spisula selbyensis, n. sp. x 1.

Spisula selbyensis, n. sp. xX 2.

Spisula ashburnerti (Gabb).

Hinge of right valve.

x

Recent.
Recent.
Recent.

Miocene.

Miocene.
Miocene.

3 (?). Cretaceous.

(After Gabb).

Spisula ashburnerii (Gabb). x
(After Gabb).

Hinge of left valve.

[342]

3 (?). Cretaceous.

UNIV, CALIF. PUBL. BULL, DEPT, GEOL, [PACKARD] VOL. 9; PL. 26

bo

[e)

EXPLANATION OF PLATE 27

Spisula ashburnerii (Gabb). x 2. Cretaceous.

Spisula gabbiana (F. M. Anderson). x1. Cretaceous.
Exterior of the type. (After Anderson).

Spisula merriami, n. sp. x 2. Eocene.
Spisula merriami, n. sp. x 2. Eocene.
Spisula tejonensis, n. sp. x 2. Hocene.
Spisula chicoensis, n. name. x1. Cretaceous.

Spisula chicoensis, n. name. x1. Cretaceous.
Hinge of left valve.

Spisula coalingensis (Arnold). x 1. Pliocene.

Spisula (?) weaveri Packard. x1. Eocene.

[344] ~

Rie, 120%

9,

[PACKARD] VOL.

CALIF. PUBL. BULL. DEPT. GEOL.

UNIV.

EXPLANATION OF PLATE 28
All figures natural size.

Fig. la. Spisula brevirostratu, n. sp. Pliocene.
Hinge of the type specimen.

Fig. 1b. Spisula brevirostrata,n.sp. Pliocene.
Exterior of the type specimen.

Fig. 2. Spisula brevirostrata, n. sp. Pliocene.

[346]

WNIVG ‘CALIF: PUBL, (BULLE, DEPT. GEOL, [PACKARD] VOL. 9, PL. 28

EXPLANATION OF PLATE 29
All figures natural size.

Fig. 1. Mulinia densata Conrad. San Pablo, Miocene.
Fig. 2. Mulinia densata Conrad. San Pablo, Miocene.

Pig: 3. Mulinia densata Conrad. San Pablo, Miocene.
Note type of umbones as compared with the figures above.

[348]

29

Fle

9,

[PACKARD] VOL.

CALIES PUBL, BULE. DEPT. GEOL,

UNIV,

EXPLANATION OF PLATE 30
All figures natural size.
Mulinia densata Conrad. San Pablo, Miocene.

Note the variation in shape in these specimens from the same
collecting locality.

[350]

UNIV, CALIF. PUBL, BULL, DEPT. GEOL, [PACKARD] VOL. 9, PL. 80

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

bo

oa

EXPLANATION OF PLATE 31

All figures natural size.

Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densateé Conrad.
Mulinia densata Conrad.

Mulinia densata Conrad.

Etchegoin, Pliocene.

Etchegoin, Pliocene.

San Pablo, Miocene.

Etchegoin, Pliocene.
Etchegoin, Pliocene.

Etchegoin, Pliocene.

[352]

UNIV CALIF. IPUBE, BULL, DERE,

GEOL,

[PACKARD] VOL. 9, PL. 31

EXPLANATION OF PLATE 32

All figures natural size.

Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densata Conrad.

Mulinia densata Conrad.

Etchegoin, Pliocene.

San Pablo, Miocene.

‘Etchegoin, Pliocene.

San Pablo, Miocene.
Etchegoin, Pliocene.

Etchegoin, Pliocene.

[354]

UNIV CALIF, PUBE. BUEL DEP, GEOL, ERACKARD]) VOL, 9) PE: G2

Fig.
Fig.
Fig.
Fig.
Fig.

oo

oO

EXPLANATION OF PLATE 33

All figures natural size.

Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densata Conrad.
Mulinia densata Conrad.

Mulinia densata Conrad.

Etchegoin, Pliocene.
San Pablo, Miocene.
Etchegoin, Pliocene.
Etchegoin, Pliocene.

Etchegoin, Pliocene.

[3856]

UNIV (CALE RUBEF BUELL, “DEPiIn, GEOL, [PACKARD] VOL. 9, PL. 83

ig. 4a.
ig. 4b.

; la:

5 alte

bo

ow

EXPLANATION OF PLATE 34

All figures natural size.

Mulinia undilifera (Weaver). Miocene.
Hinge of the type specimen.

Mulinia undilifera (Weaver). Miocene.
Exterior of the type specimen.

Mulinia undilifera (Weaver). Miocene.

Mulinia undilifera (Weaver). Miocene.

Mulinia pablocnsis,n. sp. Miocene.

Mulinia pabloensis, n. sp.

Miocene.

[358]

[BACKARDISVOLE. 9; PE e4

CALA MPUB ES BUELL. DEPT GEOL

UNIV.

EXPLANATION OF PLATE 35
Both figures natural size.

Fig. la. Schizothaerus nuttallii (Conrad). Recent.

Fig. 1b. Schizothaerus nuttallii (Conrad). Recent.

[360]

UNM. CALIF. PUBL, BULL. DEPT. GEOL, [PACKARD] VOL. 9, PL. 35

¥ «* ana ae (=

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currence of Mammalian Remains in a Pleistocene Lake Deposit at Astor i,

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. Corals from the Cretaceous and Tertiary of California | and Oregon, b
- Relations of the Invertebrate to the Vertebrate Faunal Zones of th
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F Faunal Studies in the Cretaceous of the Santa Ana Mountains of Soaeae
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. Stratigraphy and Fauna of the Tejon Eocene of California, by Roy E. “Dickerson ‘4
. Relationship of Equus to Pliohippus, Suggested by Characters of a New Spee:

‘Provinces ie Nort. America,
The Occurrence of Oligocene i é
-Bruce Tu; Clark fait. «asm mas mheae aed oem

Niomlamd 9 (3s sibs, Sie sake cies veves oie eI ale cles SRE R Menstlel tel One aioe eae Ae

Ktchegoin Formations in the North Coalinga Region, California,
DNomlandys) . .)eiete..) 2:2 <7. ole 2 fo eia: ell oie helt tele. Sle) siher ie al oye ai oie eee eae

Mailer. aie 6 aciie\e sacl eich oi Bloiehe ductal plaka istepelaystat chalet aie viata Cea tat aan oie 6 oieisie ve)
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Index in press. 3

VOLUME 10.

F THE DEPARTMENT OF
pate , wae if GEOLOGY
No. 17, pp. 363-524, plates 36-46

\

oan

BY

_ROY E. DICKERSON

v4 7 a y
UN IVERSITY OF CALIFORNIA PRESS )
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uy
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California, by Charles Laurence Baker..... CERT ee a

VOLUME 7.

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ysonian Instit,,».>
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@ Op \

} cS ,
JUN 8 1916
UNIVERSITY OF CALIFORNIA PUBLICATIONS N, ‘ .
“tional Muse™
BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 9, No. 17, pp. 363-524, pls. 36-46 Issued May 2, 1916

STRATIGRAPHY AND FAUNA OF THE TEJON
EOCENE OF CALIFORNIA

BY

ROY E. DICKERSON

CONTENTS

PAGE
MOTO GAT Cb OT Mprs! 02... Stee een Nee a eS een ol et Be Re eee 365
SACKMOWACUSIMEMtS’ ¢ 2. Ste ee VB ee 2 se ei Bl Dobe ese d 2 s ss esc we ckewnsdeceen 367
TRRNTAUS NY, COME UE OVS HPT eh of G25 a Cree OM gee 367
Descriptions of Typical Tejon Areas in California....... 2222 Byial
Mejone Group soutm of Mount Dial... ..c2 ese 2.0.0 <cs-ceecedseccoscoseencecsensaerneeeeeae Ayal
Sibu nap liye os arenes A Bai te) See EM ee aia
TELUS mes oneness Be ee eer 2) Bake. ET Ss ee Se Resch 373
UT OINO ae OMG. eer. 8 ee Coe Bie ie ee 2 PP 373
Te Tass imip lex; ZiOM Se ye cc eeeecscse=c sees ce cen oso noe eesees ceeds -dce2cccecceceeveccxe-s 374
Balanophyllia ‘variabilis’ Zome 22.22.22. neces 375
ReronmGroupeNorth of Mount Diablor .. 2222.22 ese ccc ccscteee---oeseeossee 382
SEMAN Psa. ve Sebi eee eevee der. So 2e 2c), Me nemens /oaOOEs. .05520.05325.eecee ch dec see Peet sab Ecce sees sa asnae 382
TEN EN DUDE pr bee Ia ee ge Oc eRe 384
Monemmormartiony of Californias ccctccet. ecco cce ccc cscs eck esc cee eee cccececcceeeceeteoses ove 387
The Eocene of Oroville South Table Mountain...._..00000222 ee 388
NGO CACTI ONG Stee ss ebeei kM te See Ri A, ber So ates oe 388
HET SCO 131i CA ieee pace ee Wier Sten Speke SM se 2 Ne eae 389
SUratienay hiya fe. eke eek eee. pee: eee a SE OMe Ro ees: SOK 390
Haunale Relationships <2: 22...:25 7.2 2... ee ne 392
pmhemlonevatalts “Type lOCAlity <2. :..-- een c 2 Sih once. bn esctcnecceeiedecnceapecevents 394
EO Cai O Te: 2 oc) erate SMe SE 2 DO eB ee aed eles eo 394
Turner’s Description of the Type Section — 00.0020 394
Occurrence of Eocene Fossils in the Jone —..-..00. 2.2.22... 397
Relation of the Auriferous Gravels to the Ione Formation............ 398
The Ione Formation Near Merced Falls —2000.....2.0.ceeeeeeeeeeeeeeeeeeeeceeeedeeee 398
The Ione Formation in the Vicinity of Bear Creek, Merced County... 399
Deep-Water Equivalent of the Ione at Marysville Buttes......000.0000. 403

SCR AET STAD Ny dercccc teres eas. eeeeee se eee se Me Re ee

Description of the Sutter Formation
EMIS tOTICAIMG COLOR -2::-Se ete te eeae ees ee ec ee

Summary of Fauna of the Siphonalia sutterensis Zone...................... 406

~,
x

| 364 University of California Publications in Geology [Vot. 9
PAGE
Correlation of the Ione and the Auriferous Gravels...............--..-.-.---- 409
Summary of Geological Events Along the Western Foot-hills of the
Sierral Nevada 2.:.:...02.) bescdeccsedceencccsccessckes th pee er 416
Summary ).0..........0001-53.2.-$ 0S 417
Tejon Group;im the Vicinity of) Hort Tejon __....- 2 eee 418
StratigrapWy ...:c.2cccc20 $02 El eee 418
ASOT 1 604: A | sm Be ee ES OEE UREEE EA ec oie cyanceece 418
Tejon Group, Cantua District, Coalinga Quadrangle —.........22-2.--------- 422
Historical}. -.:.......0..c.2c.--sscfincc. deed ooh Seccee sens hee 422
Stratigraphy %.......25.22.00.. 4b bbe te ee ee 424
Fauna Erpom Lowermost Beds) £23... 2.) Se 425
Fauna of White Sandstone (Member) -2.222-2 2... 428
White Shales. <..0..cs.. dee ee 435
SUMMARY hice. secsesccseckeics nee ie oe eee ee ee 435
Tejon Group in San Diego County, 20020222... ee ee 435
‘Stratigraphic Notes. ....22....8.. 20.252... Se eee 436
FPQUME, Bb eicss.ne-ccecdnreseeceteancncs-danalstodeun ae eee a 437
Comparison of Fauna with that of the Type Tejon .........-................ 439
Conclusions. .....22::.2.226.6.2.1.0.4.. 0. en eee 440
Tejon of thelSanta Ana Mountains, ..........20-2. ee 44)
Tejon Near Lower Lake, Lake County, California ....02...2200000tcccteceeeeeeeeee 441
Summary of Tejon Fauna c..-....:2.0.ncccc) ccsecccssedoe ee es eee 442
Relation of Tejon Fauna to Martinez) Wauna 122.2 ee 454
Relation of Tejon Fauna to that of the San Lorenzo Oligocene ............ 454 ;
Summary of Stratigraphy 2.::..0%-........ae.t: eee 455 |
‘Areal Distribution of Tejon Group 22..2b.12 2.2. eee 460
Geography of the Tejon Sea (i.2..22....:52...2023....)2..2.)5 1 ee ee 467
Correlation) =-2.2-2.-.....2-° O), kabenttdecttnadnaatudp cwendeteh oaeesss eee Peet aie) 474
FMISGOV UGA eerste -ote. Se Basie ies heacseebe RAE a Le ee ee 474
Species Common to the Gulf and Pacific Provinces ...........2.....2..:ce--e-eee-- 476
Stages of Evolution of Venericardia Planicosta Lamarck .....................--- 477
Generic Comparison of Midway and Tejon Faunas .........--......22-222ecs-eee--- 478
Proposed’ Correlation) ....£2.:......!/..2..2.2)i. 22... (2. 2 479
General. Conclusions. ......$- 2.5.1... hh ee ee 479
Descriptions, of New Speties, _.--....:..:282:-2- 3 eee 481
Pelecypoda) .2.::4.2s...2$.242......4.32 23. 2 lee eee 481
Acilaygabbiana, mn. iSpy" 4-2--..-:4::e eee ee ee 481
Arca) eclarki,. n.0SD. ge ...... 22 eee ee, Sea ee ee 481
Crassatellites lillisif mausp.) 22.23.22 Bb 2 2 ee ee 482 ©
Cardium marysvillensis Dickerson-..128.. 222)... es 482
Glycimeris -perrinif ni sp: |!.....24.5-.. 2 2 eee 482 | .
Glyeimeris fresnoensis, n.)|Sp: _.--t-s5..--!2-pcc-5 2. es 483
Glycimeris hannibali,.n. sp) ....-..22.42..22 2 222 ee 483
Wieda. fresnoensis, en. SDiy-::.2----:scc-- eee te 483
Iicinaspackianiasp: 22. eo. See Bh civinende Sendcsltecenst ie 484
Luecina diegoensis, My. Sp. 222-.220:0t Re ee 484 ,
Mancia (j?)) 'conradij@n: Sp: 2.22 eee A nnicbenstadecisesdent .. 484
Phacoides. (Myrtea)) taffana, no Sp. .2.....25......-5. 485
Spisula) meeriami, Packard) n. Spi 2.2322: -..cpeeece cee 435
Tivela packard, Mi. (SD i)... s.. | ee e e soccneeceennecneennnne 486 8

1916] Dickerson: Tejon Eocene of California 365

Melina JOMWAEMSIS) WisSI eee ec cases soe esac ce eee ace eee ee ce ene: 487
GaStGOD OG Gy Sere reer et cee eee ee eee eee SRD OEE RO ee reer 487
PATCHIGECTONIGA, WINE Yama, Is SP ocsccc tess cece cence ccc cee nee eeeee eee 487
PNCEA COM MINOOGY I MS Dare. corere ets se caste cteces soe cane seceu cece Got sou cSanessfeceeereeoeeereecese 488
PAGINA Been CaN ANT a sone S [pre ae eee ere ras toe nS ne oe eee ee 488
Chrysodomus martini DickerSom, ~-2.....222.c.c....----cccceneseeceeecennececceeeeseeeseense 488
Crepidula inornata, n. sp. ......00..--.--..2-02-.----- SAO ead oe: Le De | 489
Ofer eat aly ay a¥SwNShe (0 FO Hag 1 Ol Ken ign ets) 0 gies ee ee RE ee Ce eee eee 489
Cerithiopsis oOrovillemsis, m.. SDP. -...2----------------2--c<cc2cces-o-enenae-nacceeceseeaneeseee--- 489
Wray sOnOwvaAlenSiss: Ms. SPs fccecees eee ence nsec cekce nce ease seedeseneree an eese 490
Drillia COOperiy We, SP. 22---c2.cccc cece -ceno nce eecen oc ccc ceonee cence cee soso seccecccnseseseceeccecceee= 491
Epitonium tejonensis, n. SDP. -...----.- 22222. ieee eeeeee eee eee eee eee cece 491
GaleodeaySutteremsis; 1s “SPi secssscesssce-c- besos cee sects eece sees osbiedsestesesecesssse cusses 492
IMICODSIS: GOOPECTAL GiaDD: cco cc ecco soe one econ ce eres cere e see cee eee conc ceeeeceses ees uecectcene 492
EES CUO Me Well ete PO MAINE Alltel gue oS JO se eee eee ee 493
EMUSIMMIS* MENG IAMVI,. Me Se ceseccccecceeccce accesses ee seen eee eee 493
ONO CONTA Wal LUS 1 aelene SD tenascin ene, coe Ree oe, Tee ne 494
IMS GU eeaTer SUI SO yc2%, 2-2sescn2e2ee28ece oe cee eee se sec aeehoesacsadedederace-secssnceanse ueeeceteccees 494
Mitramorpha DParSOMS!, Di. (SP. 2.2. ee cece eects nee ee cee eee 495
MunexsGOcinebrayi mash, ik) Spe ssescesssessssee cesseeesee) caseeessese eee eseseeee see esses 495
IN DUI CAMS CS LOTT ay Thee 7S Dyers erent cece aeanee See ane Oi Ur 2 See OSS 496
ING ChILO Chis e Ulm aimee iS cee ose eee eee eee 496
INVGtilO Chis sdieGSOEMSIS) Wi Spey seseccesse cece seeeeee cee ee cee 497
IPETTSSOLAX SADT SDs esc ose sere re ae ne eae ae Be See ce ea ee Sec ee 497
Odostomia packi, n. sp. —.....
SURED SUGANO Wiel TG, y Me Ses ee cesses seer ee ne ee eu ee ee ee 498

Siphonalia sutterensis Dickerson
Sureula clarki Dickerson

UTC Uae CSL THs ans 2 SD) gees cstee oo ease see ere ees sac oe ay seca a ee
PMT SESUOCKI Mey SIO! cass. 202s coce ec on.cete -aeac sees cee = a reevas cee se2 sees cecdeses eeeciees eee 499
Murritella buwaldana, nm. Spl 2 .-.-2-----.-...22.-.-.-.

SUNT ISTE CCT Ae KC Wille gS YO oe peat eee nee ee ees ee meee ee ee ee
Murritellasanmdersoniles Ns SPs 2o...cccscersessseceee- 2a ee 501
Mumritela lawSOnd, Ti. SDPi seccecrs2 taste cane somes ease see eee ro seco scared eee 502
EXTCIIO DONA STOCK Men SD ep: cscseessee soe acces seane rs = SOneee ee cence onl Me ts 502

INTRODUCTION

Since Conrad first recognized Cardita planicosta, ‘‘the finger-post
of the Eocene’’, with thirteen other species in a small boulder sent
him by Blake, from the Canada de las Uvas, the question of the
occurrence of the Hocene, and later its relations, have from time to
time excited interest and, in the time of Gabb, even acute controversy
among the Pacific Coast geologists. The occurrence of great thick-
nesses of Eocene strata in the region north of Coalinga, Fresno
County, California, has recently attracted the attention of various
geologists engaged in oil work to the consideration of the divisions of

366 University of California Publications in Geology [Vou. 9

the Eocene of this coast. The stratigraphy and fauna of the Tejon
is far better known than that of the Martinez. This is due to the
somewhat greater distribution of the Tejon, its more abundant and
better preserved fauna and to a well-marked constancy in certain
phases of its lithology over all California. Stratigraphy alone is
powerless in many cases to settle the structural features, as uncon-
formable contacts with marked differences of dip and strike are gen-
erally cloaked; again, that many times there is only a disconformity
between two formations very different in age is a common experience
of the field geologist working in California. Lithology is very helpful
at times, but great danger arises when correlation or even extended
mapping is based upon this alone. Every device must be used in our
efferts to solve the intricate questions arising in connection with the
sedimentary formations, and among these, the careful determination
of fossils and study of the related faunas is not the least. Here, as
elsewhere, mistakes occur and to avoid them a thorough study of the
faunas of the various groups is necessary. This paper will attempt
to aid the geologist and palaeontologist to separate sharply the Tejon
from the Martinez by describing the faunal differences as well as the
hthological and structural ones.

The Tejon group is a unit both stratigraphically and faunally.
Minor stratigraphic breaks may occur at various horizons within the
group, but when these are evaluated by faunal studies they have
been found to be of minor importance in all cases. From the lower-
most horizon to the uppermost the faunas do not appear to be sepa-
rated sharply, and many species range throughout the entire thick-
ness of the Tejon. Very gradual changes in faunas, however, do
occur and the writer recognizes four faunal zones in the Tejon group
of California. These zones are, in ascending order, the Turbinola
zone, the Rimella simplex zone, the Balanophyllia variabilis zone,
and the Siphonalia sutterensis zone. Of these the first three are
present in the San Francisco Bay region. The uppermost is typically
exposed in the Marysville Buttes, which are located in the center of
the Sacramento Valley, and at several places along the eastern border
of the Great Valley, on the western flanks of the Sierra Nevada.
This zone may also be present in the Coalinga region. Its absence
in the Mount Diablo section is probably due to post-Tejon and pre-
Oligocene erosion, as there is a strong suggestion of unconformity
between the Oligocene, the Agasoma gravidum zone and the Tejon
at Walnut Creek. The Tejon is found in general to rest with distinct

1916 | Dickerson: Tejon Eocene of California 367

unconformity upon the rocks of the underlying formations, but strati-
graphic relations to the overlying formations are not always so clear.
The Oligocene as represented by the Agasoma gravidum zone does
not always appear to be sharply set off from the Tejon. Recent
studies in the southern end of the Great Valley made by Clark Gester
at San Emigdio and John Ruckman at Coalinga appear to show inter-
eradation between the two groups. Faunally, however, the Tejon is
distinct from both the Martinez EKocene below and the Agasoma gray-
idum zone (Oligocene) above.

The Ione formation of the Sierra Nevada foothill region is the
uppermost member of the Tejon group and, as will be shown later,
is the marine equivalent of a great portion of the Superjacent series,
the land and stream-laid deposits of the Sierra Nevada.

ACKNOWLEDGMENTS

The writer is indebted to Mr. J. A. Taff and to Mr. G. C. Gester
of the Southern Pacifie Company for the facilities of their camp on
Salt Creek and for their guidance in the field to the best collecting
localities. It was the intention of Mr. Gester and the writer to describe
the Cantua region in a joint paper, but this was prevented by Mr.
Gester’s departure for Peru. The faunal relations are so important
that it was thought best to publish these results now and the complete
stratigraphic discussion later.

The Tejon collections made by the December, 1913, field party of
the Department of Palaeontology of the University of California were
turned over to the writer by Dr. B. L. Clark and Mr. John Ruekman.
The writer is especially indebted to Professor J. C. Merriam for the
opportunity to make this investigation and for his kind eriticism
during its progress.

The writer has been assisted in this work by many persons. Pro-
fessor J. C. Merriam, Dr. B. L. Clark, Dr. J. P. Buwalda, Dr. E. L.
Packard, Mr. W. 8S. W. Kew, Mr. J. Ruckman, Mr. W. Gordon and
other members of the 1911 and 1912 Summer Sehool classes in
Palaeontology rendered much help in the work in the Mount Diablo
region.

REVIEW OF THE LITERATURE

The literature of the Tejon group is so voluminous that only the
principal papers will be reviewed. These papers deal with age, fauna;

368 University of California Publications in Geology [Vor. 9

correlation, distribution and stratigraphy of the upper Eocene of
California.

The first recognition of Eocene on the Pacific Coast was made by
Conrad, and was based upon the fossils contained in a boulder sent
by Blake from Caftada de las Uvas.

Conrad described the following new species: Cardium lintewm,
Dosima alta, Meretriz wvasana, Meretrix californiana, Crassatella
uvasana, Mytilus humerus, Volutilithes californica, Busycon(?) blakei
—=(Perissolax blakei), Clavatula(?) californica=(Fusinus califor-
nicus), Natica alveata=(Amauropsis alveata), and he identified Ven-
ericardia planicosta, Natica aetites(?), Natica gibbosa and Crassatella
alta of the Claiborne Eocene.

Gabb* in 1864 described many species which Captain Horn col-
lected from the vicinity of Cafiada de las Uvas and referred the
strata yielding this fauna to Division B of the Cretaceous. Whitney*
in the next volume described the type locality of the Tejon-Eocene
as follows:

The Tejon group ... the division B of Palaeontology, vol. 1, is peculiar
to California. It is found most extensively developed in the vicinity of Fort
Tejon and about Martinez. From the latter locality it forms an almost
continuous belt in the Coast Ranges to Marshs’, 15 miles east of Mount
Diablo, where it sinks under the San Joaquin plain. It was also discovered
by the different members of the survey at various points on the eastern
face of the same range as far south as New Idria, and in the summer of
1866 by Mr. Gabb in Mendocino County, near Round Valley, the latter
locality being the most northern point at which it is as yet known. ...

This group contains a large and highly characteristic series of fossils,
the larger part peculiar to itself, while a considerable percentage is found
extending below into the next group (Martinez).

For several years the controversy concerning the age of the

1 Pacific Railroad Reports, App. to Prelim. Geol. Rept. of W. P. Blake,
Palaeontology, pp. 5-20, 1855. Reprinted in Pacific Railroad Reports, vol. 5,
part 2, pp. 317-329, 1857.

2Gabb, Wm., Geological Survey of California, Palaeontology, vol. 1, 1864.

3 Whitney, J. D., Geological Survey of California, Palaeontology, vol. 2,
p. 19 of preface, 1869.

4 Conrad, T. A., Observations on Certain Hocene Fossils described as Cre-
taceous, by W. M. Gabb in his Report published in Palaeontology of Cali-
fornia, Am. Jour. Conchol., vol. 1, pp. 362-365, 1865; Further Observations
on Mr. Gabb’s Palaeontology of California, Am. Jour. Conchol., vol. 2, pp.
97-100, 1866; Check list of Invertebrate Fossils of North America, Eocene
and Oligocene, p. 37, Smithsonian Misc. Coll. No. 200, 1866; Am. Jour. Sci.,
2nd series, vol. 44, pp. 376-377, 1867.

5 Gabb, W. M., Reply to Mr. Conrad’s Criticism on Mr. Gabb’s Report on
the Palaeontology of California, Am. Jour. Conchol. vol. 2, pp. 87-92, 1866;
Amer. Jour. Sci., 2nd series, vol. 44, pp. 226-229, 1867; On the Subdivisions of
the Cretaceous Formation in California, Cal. Acad. Sci. Proc., Ist series, vol.
3, pp. 301-306, 1867; Geol. Surv. California, Palaeontology, vol. 2, 1869.

1916] Dickerson: Tejon Eocene of California 369

Tejon was waged. Conrad,‘ Gabb,? Whitney," Cooper,‘ Marcou,®
Heilprin,®? Newberry,’® White,'! Becker,’? Clark,* Harris,** Diller,”
all contributed to this question. The Cretaceous ghost of the
Tejon was finally laid by Stanton'® and Merriam.’* Most of the
papers cited deal with the Tejon in general, and direct references
to the type locahty are few in number.

The reader is referred to the papers by Clark and Stanton
for a more complete review of the literature concerning the age
and correlation of the Tejon.

Anderson'* mapped an area in the southern end of the San
Joaquin Valley which included the type locality of the Tejon
group and he described the stratigraphic relations there.

Watts,’ Cooper,”? Lindgren and Turner** described the
stratigraphy and fauna of the Tejon of the Marysville Buttes

6 Whitney, J. D., Geol. Surv. California, Palaeontology, vol. 2, 1869.

7 Cooper, J. G., The Eocene Epoch in California—Are there really no
Eocene Strata?, Cal. Acad. Sci. Proc., 1st series, vol. 5, pp. 419-421, 1874.

8 Marcou, J., Ann. Rept. Geog. Surv. West 100° Merid., pp. 167-169, 1876;
Note sur la géologie de la Californie; Bull. Soc. géol. France, 38rd series,
vol. 11, pp. 407-435, 1883.

9 Heilprin, A., On the Occurrence of Ammonites in Deposits of Tertiary
Age, Proc. Acad. Nat. Sci. Phila., vol. 34, p. 94, 1882; On the Age of the Tejon
Rocks of California, and the Occurrence of Ammonitic Remains in Tertiary
Deposits, Proc. Acad. Nat. Sci., Phila., vol. 34, pp. 196-214, 1882.

10 Newberry, J. S., On Supposed Tertiary Ammonites, Proc. Acad. Nat.
Sci., Phila., vol. 34, pp. 194-195, 1882.

11 White, C. A., On Marine Eocene, Fresh-Water Miocene and other fossil
Mollusca of Western North America, Bull. 18, U. S. Geol. Surv., pp. 7-9, 1885.

12 Becker, G. F., Notes on the Stratigraphy of California, Bull. 19, U. S.
Geol. Surv., pp. 1-25, 1885.

13 Clark, Wm., Correlation Essays, Eocene, Bull. 83, U. S. Geol. Surv., pp.
95-110, 1891.

14 Harris, G. D., Correlation of the Tejon with Eocene Stages of the Gulf
Slope, Science, vol. 22, p. 97, 1893.

15 Diller, J. S., Bull. Geol. Soc. Am., vol. 4, pp. 218-220, 1893.

16 Stanton, T. W., The Faunal Relations of the Eocene and Upper Creta-
ceous on the Pacific Coast, 17th Annual Report, U. S. Geol. Surv., pp. 1011-
1059, 1896.

17 Merriam, J. C., The Geological Relations of the Martinez Group of Cali-
fornia at the Typical Locality, Jour. Geol., vol. 5, pp. 767-775, 1897.

18 Anderson, R. V., Preliminary Report on the Geology and Possible Oil
Resources of the South End of the San Joaquin Valley, Cal., Bull. 471, U. S.
Geol. Surv., pp. 117-119, 1912.

19 Watts, W. L., The Gas and Petroleum Yielding Formations of the
Central Valley of California, Bull. No. 3, California State Mining Bureau,
Aug., 1894, pp. 9-10.

20 Cooper, J. G., Catalogue of California Fossils, Bull. No. 4, California
State Mining Bureau, Sept. 1894, pp. 36-45.

21 Lindgren, W., and Turner, H. W., Marysville Folio, U. S. Geol. Surv.,
Folio 17, April, 1895.

370 University of California Publications in Geology [ Vou. 9

region in 1894 and 1895. Cooper in Bulletin No. 4 also described sey-
eral forms from the Tejon Eocene of San Diego and Coalinga. In a
general correlation paper, Dall*? placed both the Martinez and the
Tejon as the correlative of the Midway stage of the southeastern
United States and the Cernaysian of Europe. Lawson? in a general
descriptive paper on the geology of Central California described the
Tejon group in the Concord Quadrangle.

During the last ten years most of the literature dealing with
the Tejon group is in connection with geological mapping and oil
investigations. Eldridge and Arnold,** Arnold,?> Arnold and
Robert Anderson,*° Arnold and Johnson," F. M. Anderson,?5
Dumble,?® Robert Anderson,*° Lindgren,*! Dickerson,*? Lawson,*?
MeLaughlin and Waring,** have added to the knowledge of the
distribution of the Tejon in California and have incidentally de-

scribed several new species.

22 Dall, W. H., A Table of the North American Tertiary Horizons corre-
lated with one another and with those of Western Europe, 18th Annual
Report, U. S. Geol. Surv., part 2, pp. 327-348, 1898.

23 Lawson, A. C., A Geological Section of the Middle Coast Ranges of
California, Science, n. s., vol. 15, p. 416, 1902.

24 Widridge, G. H., and Arnold, R., The Santa Clara Valley, Puente Hills
and Los Angeles Oil Districts, Southern California, Bull. 309, U. S. Geol.
Surv., 1907.

25 Arnold, R., Geology and Oil Resources of the Summerland District,
Santa Barbara County, California, Bull. 321, U. S. Geol. Surv., 1907.

26 Arnold, R., and Anderson, Robert, Geology and Oil Resources of the
Santa Maria Oil Distret, Bull. 322, U. S. Geol. Surv., 1907.

27 Arnold, R., and Johnson, H., Preliminary Report on the McKittrick-
Sunset Oil Region, Bull. 406, U. S. Geol. Surv., 1910.

2s Anderson, F. M., A Stratigraphic Study in the Mount Diablo Range of °
California, Proc. Cal. Acad. Sci., 3rd ser., Geology, vol. 2, pp. 156-248, 1905.

A Further Stratigraphic Study in the Mount Diablo Range of California,
Proc. Cal. Acad. Sci., 4th ser., vol. 3, 1908.

29 Dumble, E. T., Notes on Tertiary Deposits near Coalinga Oil Field and
their Stratigraphic Relations with Upper Cretaceous, Jour. Geol., vol. 20, pp.
28-37, 1912.

30 Anderson, R., Preliminary Report on the Geology of the Oil Prospects
of the Cantua-Panoche Region, California, Bull. 43la, U. S. Geol. Surv., 1909.

Preliminary Report on the Geology and Possible Oil Resources of the
Southern End of the San Joaquin Valley, Bull. 47la, U. S. Geol. Surv., 1912.

31 Lindgren, W., Tertiary Gravels of the Sierra Nevada of California, Pro-
fessional Paper No. 73, U. S. Geol. Surv., 1911.

32 Dickerson, R. E., Fauna of the Martinez Eocene of California, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 8, pp. 61-180, 1914; The Martinez and
Tejon Groups and Associated Formations of the Santa Ana Mountains, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 8, pp. 257-274A, 1914.

33 Lawson, A. C., San Francisco Folio, U. S. Geol. Surv. Folio 193, 1914.

34 McLaughlin and Waring, C. A., Petroleum Industry of California and
Map Folio to accompany Bull. No. 69, Cal. State Mining Bureau, 1915.

a
aa.
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LAEONTOLOGY

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SAR Y SMG DS AS
ee

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Mar SHowrne Tegon anv AssocraTep Groups IN AREA SoutH oF Mount Drasto. Mapping By 1911 anv 1912 Summer ScHoot CLasses IN PALAEONTOLOGY

awd. Rb given davameneA anh How?

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tel)

eae

1916 | Dickerson: Tejon Eocene of California aval

Arnold,®* Pack,** Dickerson®* and Waring** have contributed
papers dealing with the fauna of the upper Eocene of California.

DESCRIPTIONS OF TYPICAL TEJON AREAS IN CALIFORNIA

Trson Groupe SourH or Mount DiABio
STRATIGRAPHY

The Tejon group south of Mount Diablo is a northwest-south-
east strip about ten miles in length. It has an unconformable
relation to the underlying Chico and Martinez. For a distance
of six miles this unconformity is marked by basal Tejon strata
containing boring shells which penetrate the underlying Chico or
Martinez rocks. In some places these borings are found in lime-
stone of Martinez age, again in Chico sandstone and Chico lime-
stone containing fragments of Znoceramus. (See Figure 1 and map.)

Cave Fx
2loorye.

up
Hf ')
er ty
~ iy Al} &
<i th “)
fi 7 Tp
, hy) ny Th,
/ Hy AY
th mh hey Hy] [2
il HAL ALLA

Fig. 1. A North-South section through Cave Point on the north and
Oyster Point Ridge on the south. Chico strata are indicated on the ex-
treme left of the figure while Miocene sandstone is shown on the extreme
right.

The Tejon is overlain by the Monterey and Oligocene. No differ-
ence in dip and strike was found between the Tejon and the over-
lying formations in this field. An unconformity or disconformity
probably exists here. At a locality in the bed of Walnut Creek
about one and one-half miles southwest of the town of that name,

35 Arnold, Ralph, Palaeontology of the Coalinga District, Bull. 396, U. S.
Geol. Surv., 1909.

36 Pack, R. W., Notes on Echinoids from the Tertiary of California, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 5, No. 18, 1910.

37 Dickerson, R. E., Fauna of the Eocene at the Marysville Buttes, Cali-
fornia, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, pp. 257-298, 1913; Note on
the Faunal Zones of the Tejon Group, ibid., vol. 8, pp. 12-25, 1914; Fauna of
the Martinez Eocene of California, ibid., vol. 8, pp. 61-180, 1914; The Ione
Formation of the Sierra Nevada Foothills, Science, n. s., vol. 40, July 10, 1914.

38 Waring, C. A., Eocene Horizons of California, Jour. Geol., vol. 22, pp.
782-785, 1915.

one University of California Publications in Geology [Vor. 9

the overlying Oligocene beds contain water-worn fragments of coal
and sandstone of probable Tejon age which were evidently derived
from the underlying Tejon. Walnut Creek is only a short dis-

tance from the Tejon area south of Mount Diablo and conditions
are probably the same in both places. (See Figure 2.)

Monterey , l-Oringe = }Saa Pablo Monterey |ZejonA-Al/u vier
“(ae 1 role. ff LE OL

core
Scure//e
orewer/ane
Zore

Arce
Upper Zore
LowerZore

Lower Zor7e
Opper Zone

FRANKLIN PAULY

TN
AN
AXON
ANA
KAMRAN

Bie 2: Section showing Tejon strata and associated rocks in the vicinity

of Walnut Creek, Concord Quadrangle. (After Lawson.)

Wi

The following section through Cave Point was measured by Mr.
Ilham Kew and the writer. Figure 1 shows the relations

graphically.

(al
(2
(3
(4
(5
(6
we

(8
(9
(10
(ut
(12
(13

(14
(15
(16
(alg
(18
(19
(20
(21

(22

SECTION OF THE TEJON GROUP SOUTH or Mount DIABLo
Chico sandstone and limestone.

) Conglomerate

) Thin-bedded gray sandstone, 2. eee 20
iGray, foraminiferal’ shialewcs ess eee en ee 75
i Hard seray. Sandstone: ee se eee 40

) Massive tan sandstone 20

) Gray-green foraminiferal shale cece cece eeteeeeceeeee 25
) Light-tan coarse sandstone with cavernous weathering, first

MOU UE eee J5 ce can aoc 8c ge ee ecco enna ee ct 125
) Alternating soft sandstones and carbonaceous shales... 200
) Sandstones with interbedded shales...... 22... .... eee ceecee cece eeeeeeeeeeeee eee eee 307
) “hin-bedded! (samdistones ts 50
) Shale with thin-bedded sandstone... 2... ...eeeceeeceeeeee ceeeeeeeeeeeceeeeeeeeeees 63
) Thin-bedded sandstone with Twurritella uwvasana beds on top... 100
) Massive soft sandstone with Turritella wvasana beds, second

POMEL saa. 2c ot ce eae eo eee see Ne Ss ae 100
) Massive tan sandstone, second bluff. 390
DiS Waal 2. sense me eel ae eee 100
) Tight” gray Samdstome ce 8
) Carbonaceous shale and thin-bedded sandstone. 45
) Massive tan sandstone, third bluff... 554
) Carbonaceous shales and lignite 25

) Massive tan sandstone
) Blue shale

eae

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ot

LIST OF SPECIES COLLECTED FROM BASAL TRJON
143° 472 475 476 701 702 703 709

STRATA SOUTH OF MOUNT DIABLO

‘ 717 718 719 723 728 732 734 1415 1420 1429 1430 1482 337 532
yummulotd(?)» SP- aac Cb om os Sr = - =
rnitoides: bs
pinold spines
P yaastel lecont

tla, SP» =~
ser lus californicus Anderson ...

gtephanophy lia californica Nomland .

Sbinotia dickersont Nomland -

qurbinolia pusilianima Nomlang!
sinuata Nomland

ei Merriam

cardi
aa cooperii Gabb ..
Corbula nornli Gabb -..
Corbula parilis Gabb
Dosinia elevata Gabb ....
Glycimeris sagittatus (Gabb) -
Jeda gabbi Conrad
Lueina gyrata (Gabb) ..
Lucina cumulata Gabb -
Meretrix hornii Gabb -...
Meretrix tejonensis Dickerson .
Meretrix ovalis Gabb
Marcia quadrata (Gabb) .
Macrocallista conradiana (Gabb)
Modiolus merriami (Weaver) ..
Modiolus ornatus (Gabb) ...
Ostrea, SP. -
Pholadidea, Sp.
Pecten interradiatus Gabb
Psammobia hornii (Gabb)
Paphia conradi, n, Sp. --.-
Placunanomia inornata Gabb
Solen parallelus Gabb
Solen stantoni Weaver ..
spisula merriami Packard
Tellina longa Gabb ....
Tellina remondii Gabb.
Tellina, sp. ......
Tellina martinezensis Weaver
Tellina diegoensis, n. sp. -...
Thracla karquinezensis Weaver
Teredo, sp.
Yoldla, sp.
Venericardia planicosta hornii (Gabb) .
Cadulus pusillus (Gabb) .....
Tentalium stramineum Gabb
Aemaea, sp. a. .......
Amauropsis alveata (Conrad) ..
Acacon, sp. .......
Ancilla (Oliverato) californica Cooper ..
Bullaria hornii (Gabb)
Bela, of. clathrata Gabb.
Cylichna costata Gabb
Conus remondii Gabb ...
Caneellaria stantoni Dickerson -
Chrysodomus supraplicata (Gabb)
Chrysodomus, sp.
Bltcsitn, SD.
Erilia perkinslana (Cooper) ..
Fusinus martinez (Gabb) -...
Fusinus mathewsonil (Gabb)
Fusinus californicus (Conrad)
Fusinus, sp.
Fasciolaria sinuata Gabb
Ficopsis remondii Gabb
Galeodea tuberculata (Gabb)
Lunatia nuciformis Gabb
Megistostoma striata Gabb -
Metula harrisi, n. sp.
Natica gesteri, n. sp.
Naticina obliqua Gabb
Neverita secta Gabb ...
Nyctilochus hornii (Gabb)
Nyctilochus impressus (Weaver)
Nyctilochus eocenicus (Weaver)
Olivella mathewsonli Gabb ....
Perissolax blakei (Conrad)
Perissolax gabbi, n. sD. -..
Pseudoliva yolutaeformis Gabb
Rimella canalifera Gabb —..
Spiroglyphus(?) tejonensis Arnold
Surcula, sp.
Strepsidura howardi, n. sp.
Turritella uvasana Conrad
Turritella merriami Dickerson .
Turritella conica Weaver -.
Turritella buwaldana, n. sp.
Turris monolifera (Cooper)
Whitneya ficus Gabb
Nautilus, sp. --..

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as
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1916] Dickerson: Tejon Eocene of California B13

The Tejon on the south side of Mount Diablo is on the average
about 2600 feet thick and it has a general strike of N 60° W. In
the northwestern portion of the area under discussion, it has a
dip of 60° south in Pine Canon. Going southward along the strike,
these strata become vertical and finally overturned in the vicinity
of Cave Point, where they have a dip of 70° to 85° N. Two to three
miles southeast of Cave Point the Tejon is pinched out by a
great overthrust fault. Very extensive collections were made
throughout the entire extent of the Tejon. A particularly good
section for study was found in an unfaulted area lying between
Cave Point and Oyster Point. At least three faunal zones were
recognized in this area.

FAUNA

TURBINOLIA ZONE

A very large fauna was obtained from the basal beds. These
strata, consisting of four to five feet of irregularly bedded lime-
stone, conglomerate, and hard calcareous sandstone, and about two
feet of thin-bedded sandstone, lie uneconformably upon the Chico
limestone and sandstone. Numerous pholad borings mark this
ancient shoreline of the Tejon sea. This same horizon also occurs
in the Pacheco syncline near Muir Station, Coneord Quadrangle.
The last three localities listed below are from this vicinity. A list
of species from the Turbinolia Zone is given below:

Nummuloid(?), sp., Thamnasteria sinuata Nomland, Turbinolia
pusillanima Nomland, Yoldia(?), sp., Thracia karquinezensis Weaver,
Tellina martinezensis Weaver, Paphia conradi, n. sp., Pholadidea, sp.,
Metula harrisi, n. sp., Natica gesteri, n. sp., Nyctilochus eocenicus
(Weaver), Strepsidura howardi, n. sp., and Perissolax gabbi. n. sp.,
appear to be restricted to this zone. Modiolus merriami (Weaver),
Solen stantonti Weaver, and Turritella conica Weaver are forms which
occur in the underlying Martinez but are not found in the Tejon of
the type locality. Dosina elevata Gabb and Lucina gyrata (Gabb),
although not characteristic, are very common at this horizon. Leda
gabbi Conrad makes up a large bulk of the thin-bedded sandstones
of this member. The rarity of Turritella wvasana Conrad and the
absence of Rimella simplex Gabb are particularly noteworthy, as

374 University of California Publications in Geology [VoL. 9

they are the most characteristic forms of the Rimella simplex zone
of the Tejon group.

Above the basal portion is about twenty-five to fifty feet of a
deep-water facies of this zone consisting of fine-grained, gray, fora-
miniferal shales, which yielded Pecten interradiatus Gabb, Schizaster
lecontet Merriam, Venericardia planicosta Lamarck, and several spe-
cies of foraminifers. These beds, which were evidently deposited in
moderately deep water as the presence of glauconite and abundance
of Schizaster leconter and foraminifers show, are far better devel-
oped in the south limb of Pacheco Syncline, where they have yielded
the fauna listed under localities 215, 337, 532. This facies is not
quite so well developed south of Mount Diablo as in the Pacheco
Syneline.

The stratigraphic position of the beds yielding the Turbinolia
fauna, the presence of several species which are generally charac-
teristic of the Martinez, the presence of several species which appear
to be restricted to the Turbinolia zone, and the absence of several
characteristic forms common in the Rimella simplex zone indicate a
life condition which is decidedly closer to the Martinez, the lower
Eocene, than that of the Tejon of Canada de las Uvas. However,
the presence of seventy-five or eighty species typical of the Tejon
of the type locality connects this fauna with that of the Rimella
simplex zone and shows that both are zonal phases of the upper
Eocene, the Tejon group.

RIMELLA SIMPLEX ZONE

Resting upon the gray-green shales of the Turbinolia zone are
from one hundred to two hundred feet of massive tan sandstones
constituting the first ‘‘bluff sandstone’’. As the name implies, these
strata have a very characteristic weathering habit, a tendency to
form prominent walls and caves.

Above the first bluff is seven hundred feet of strata made up of
alternating thin-bedded sandstones and carbonaceous shales which at
places contain thin seams of lignite. This apparently represents
several local oscillations of the coast in Tejon time, thus giving rise
to marine littoral, brackish, or even fresh-water conditions. Its
fauna is the same as the one obtained above the first bluff sandstone.
Turritella andersoni, n. sp. was found in the upper portion of these
beds. This species is also common in the Eocene beds northwest of
Coalinga which have been referred to the Martinez, but its oecur-

w

~
\

—)

1916] Dickerson: Tejon Eocene of California F

rence here, taken together with other evidence, proves that this ref-
erence is incorrect.

The second bluff sandstone of one to two hundred feet overlies
the thin-bedded sandstones and carbonaceous shales. It is for the
most part non-fossiliferous. In sandstone about one hundred feet
above, was obtained a fauna which is similar to that of the first bluff
sandstone. The similarity in fauna of these two horizons indicates
that the time represented by the seven hundred feet of alternating
shales and sandstones and minor unconformities between some of
the beds was comparatively short.

Separated from the second bluff by alternating shales and sand-
stones is the third bluff, consisting of a massive tan rock, weathering
in a manner similar to that of the other, but giving outcrops not
quite so prominent. This bluff is 550 feet thick and non-fossilif-
erous in the eastern end but two or three collecting localities occur
in equivalent strata in the western portion. These three bluffs and
the intervening strata seem to contain but one fauna, and on this
account this great thickness is included in the Rimella simplex zone.
Furthermore, similar conditions are found north of Coalinga and
at the type locality of the Tejon.

The lists on pp. 376-377 contain the species which have been found
in the Rimella simplex zone south of Mount Diablo:

This fauna contains most of the species common in the Tejon.
It is characterized by the presence of Rimella simplex Gabb, Veneri-
cardia planicosta horn, Turritella weasana, Crassatellites wvasana,
Conus remondii, Whitneya ficus, and many other forms which are
abundant at the type locality of the Tejon. Apparently the same
faunal stage is present in both places.

BALANOPHYLLIA VARIABILIS ZONE

The remainder of the Tejon may be grouped as alternations of
carbonaceous shales and fine-grained sandstones. Within this upper
horizon, extending from 400 to 800 feet below the Monterey con-
tact, are found abundantly fossiliferous strata having for their most
characteristic fossil the coral Balanophyllia variabilis Nomland,
which is associated here with Schizaster lecontei and Cardium cooper.
This zone appears to be somewhat lower than the uppermost Eocene
of the Marysville Buttes region. Some of these strata were deposited
in moderately deep water, although carbonaceous deposits found just

University of California Publications in Geology — {Vou. 9

376

OSFL

Re 5 x =
AX — x

ts ee Y
x x et

T@PL S3Ft sIlfl GFL 6éL
OUdVId ENIOW AO

x x Coe Boos Saas x tosis ia Spe sad es Aa Ge NY pieyoed lweliseut epnsidg
x ars Bad rao ES x oa alge a aaa cae Sng qqexy) sneered uwelog
sot Sage Seas as ean2 ae Seay WP far stars or aa ea cea UoSIIYIIq ISMOIIVG BUUTG
ae sane ae cae Fate 253 SEE a) REE tac aaa One oe ‘ds ‘u ‘Ipeauoos ‘jo ‘erydedg
aaa pons ares Sars ee aaa SREROMn © coe venmenmc gaat rehr By, qqey B]VUIOUL BITULOURUNOe[ qd
x x ee ane x sree ag ta ra aaa (qqey) TuU1oy BvrIqoTIUesSd
ca ete Saiz ae Bene Co EA easiest aan name Der sear mie ‘ds ‘voi1so
Pps te x ae ao aes Sea rita) tind iaotesmieteaarien tt 1k qqeyy SnjeUurO SNTOIpoy
Bee mule seus Bee x aac Soi e tr uiggerg eet a qqer) VURIPRIUOD BIST[[VIO1IVIN
x UOSIIYIIC, SISUBUOLS} XIA1}o1ON
x ones age : a 5 Me. ws gk oa geen ne oneal qqey TUIOY XiIj}o10]
aa ae Sas a5 sae ss po ARs =a ager 0g sa a qqey SI[TBAO XII}o10]
==52 x ea are Bae a Sogn 7 Wana c"> gaceemad ew Cope eet Cee ‘ds ‘eurpon’y
ae ae aie Pas ae Siee cro, nya so micaarcrgn ss eee ae (qqey) eByeIhks BUD]
os = Te so sees one 7 = 2ao ao anal qqey eyenUIND BUNT
Sze x naa mae x See aero, RRR cs | peru0g Iqqes Bpo'T
aa “a ees aaa < sia cosa Sasnigesten Sgr age Ve SULIVA STSUsUOfs} UMTpsreo0sT
a aa ioe a ; van a aia a a oS qqey B1eISeS STIOUIPOATH
x x ae 232 x ea Sr jh) Gea eae ane ae rea qqey Tusoy PINqI0D
Bees S255 Bene aa eae a Scam Eentiipegn ee ow aes qqexyy VURSBAN So}I][[I}VSSBID
x aSSe =e oe mae Pate fsa gssatsea vinsage oso ipa gems qqey Waomorq UMIpse)

Se aia AE qqexy) Tlxodooo wnipie)

Saar x ied ae Sere faa SacTUD Sevaasa ace cael aT qqey usl0y voly
acre bs cane Sa ners paaa Sosa cs oats as ana an ne ‘ds ‘U ‘Tyaepo Boy
gr scat aa ‘ds ‘vory

aa ie Ss i x naa ca oar, aa ca a ‘ds ‘u ‘Rpuviqqes P[lDV
Sans aa = ae ies a » a gaubeieaey an ces ea WPRIIIa ToJUOIIT 19ISVZIYIS
acca a ne aoe ae ee aha hbk PPC naa STEM oS ‘ds ‘sny}eAdOooLyL
a oe an ae cane Sai SG cease aad ies qqey snyerys snyyexoooory,
la aa ae ST purlwoN siperrodwy snyyeAoTOoLL

9@L STL ett TLr OLF 80L 90T

HLNOS AUNOZ XWIGWIS WIIGNIY AHL WOU sd badds JO Sl

tt

on Eocene of California

Tej

Dickerson

1916]

i A
x Xx
x x

Sia. Teatgste capcny a cesepecs tiga aigaen™ wis MBID UvIdV]SNA)
aS ea he at ae qqey) snoy BAOUIIYU AM
Sei. YP EOS ee ye ‘ds ‘u ‘TuOSIepuUe BI [ean
spo bare aaa acti ‘ds ‘u ‘vurpremnqd e[[elaiainy,

Spec eee UOSTJIYOIC TWRUEOUL PI[O}TIIN
“peiluoyj VUBSBAN BI[OIIIN

Pp prec ee acoagen sr see (19d00)) SUBISUODUT SILaNy,

SS ayey umn aay og Mt ee ae eC See. TLn ly

estas eae] ploury stsueuofe, (%)snyddpsoatds
egegiier iis Swe ee qqey BIoJI[TBUBI PBI[OUIIY

ase ese acim eng te ie eta qqey xXo9[duIs Bley

““(peluon) Laye[q XBlosslieg
oa oe aed en (qqey) IUIOY SNTO[MIAN

Sao deen ose ogee an aang qqexyy enbijqo BvuUulneNn
canes tanec (qqey)) Ble[NdIIqN}] Bvapos[ey
PRES) |“ secoronsereccasaecscrcocsectocesteks ‘ds ‘U ‘TUIBIIIOUL SNUISN YT
Seth | Spo ctacc sateen eersec sees (qqex)) ILUOSMOY}eU SNUISNYy

Sales ee cai acre ore qqexy) Ilpuoulel sisdoory

aa lea aaa ea (19d00)) BUBISUTyIed BITIX
Sa ae earns eae ae reds qqexy) Irpuotier snuog
MEO Sresecrsessrsachsccseersascase (Q(qerx)) BOLIQUGDXO BaRITdA[BO

i eeiclar iarre eaaa qqexyy e1e¥1S00 BUYdITAD
Sa a peat cesta eakask 5 esate cna (qqer)) Irus0oy Blrelpng
Se eae aS aa a Sine eae qqey eB]eVSUO[a BIIe[[IDUY
x (peluo)) ve] BoOATR SIsdoineulry
Me srrresenaeessacaceesass qqeyy eeUSsOO “JO ‘vVOTUOAIINOIV
Sa teagan ask ier cea eee aces (qqery) sntissnd sninpep
) irene (qqey) IfuUIOY BJSOOIUR[d VIPIVdITIOUI A
i agtieny Med a ceca eet gaa eigee, qqey BSUOL BUITIAL
Bae a ee cay qqey Mmpuowieat PeUr[[aAL

‘ds ‘eul[ [aL

378 University of California Publications in Geology Vou. 9

below them indicate that the land was not in a stable condition at that
time. The species obtained from these beds are as follows:

List oF Species From LOCALITIES IN THE BALANOPHYLLIA VARIABILIS ZONE,
SourH or Mount DIABLo

469 477 714 720 725 729 730

Balanophyllia variabilis Nomland.............-... x DEA es Xa
Trochocyathus striatus (Gabb) 00000000...

Turbinolia dickersoni Nomland ............... -... 22, Get bee x
Schizaster lecontei Merriam ...........-.....--.. ---- Ses ES 4) |
PACAP ENO TEIUED 3 Gre 1D Deepa sears caters cee een

Cardium cooperii Gabb 0.0202... ee Ke x
Cardium brewerii Gabb ow... ane

Corbula parilis Gabb ow... x :
Corbula hornii Gabb _ oe x
Dosinia elevata Gabb oo. x

Glycimeris sagittatus (Gabb) —............... x

IDiuiCcrbo keh Cehba aol ben ereh UC t21) of yes eee ee <u Hea 2 Sx
Leda fresnoensis, nN. SDP. -.-.--222222.---eeeeee eee ee Le i
Wedare salt Comrade saz seerere ere se-eeecescceeeeseeeeee x ee x
Meretrix tejonensis Dickerson x
Meretrix hornii Gabb o.oo... ees Re feet
Macrocallista conradiana (Gabb) ~.......... ee x
Modiolus ornatus Gabb ....WW..002..2...eecseeeeee eee bree eee
Psammobia hornii (Gabb) ee, 2k 1
Spisula tejonensis Packard ..................... ale ee Ee x
Spisula merriami Packard _... 0... é ex
SOLE TiS Dy aeteereeete sees ase sea ee er se

Semele diaboli Dickerson.................00......... x E
Telling, Vomiea, Gap: <2ec soccer nccec sec eceecceeeceee eA eee coe x
Tellina remondii Gabb ..222W..-.....---....-

Tellina cf. aequalis Gabb —...000..20222222e.

Mellinia, JOWUaAenSIS; MW. SP. vecsccccsce cesses eee eees

4) Gee net © Ree ec Sacre eee

Tellina sutterensis Dickerson __... M uo 326 22 See
GUT ae SD stake ee ee ee a as a XK

Venericardia planicosta hornii (Gabb).... x

Cadulus pusillus (Gabb) —W..000.00.22.---------..

Dentalium stramineum Gabb .................... i Sed pe ee
Amauropsis alveata (Conrad) -........-..... Kee, en Sees x
Ancillaria elongata Gabb ee ee x
(Qloraiish.” ieee pare A

(Gfopah ees refeveaovatoull {CyzHo)sy See en oe x
Conus cowlitzensis Weaver Ne ee
C@yvlichniavcostata.:Gab Wace (Mea eee x
Cancellaria stantoni Dickerson ................ x en ae
Chrysodomus supraplicata Gabb ~............ x ae, Ga ie
Ficopsis remondii Gabb 20 Se eee On 5%
Galeodea tuberculata (Gabb) -....00022....... SC ke pest x

Lunatia nuciformis Gabb ........00000000020. oe

1916] Dickerson: Tejon Eocene of California 379

List oF SPECIES From LOCALITIES IN THE BALANOPHYLLIA VARIABILIS ZONE,
SourH oF Mounr Dtasito—(Continued)

469 477 714 720 725 729 730

INGVierita: SCCtas Ga) cccccrceccccsece-oresensese-ceeeceees one i eee Ete Fe
INassa ambiquata: Gab 2 ccccccceceecseecsceece-eeene x

Nassa cretacea Gabb ............2022......---.---eeeeee oe ee
Nyctilochus hornii (Gabb) —......0.0200022-02... ---- Beem ety eee
Olivella mathewsonii Gabb —.........-......... x

Pseudoliva lineata Gabb ...........020000.........- x

Perissolax blakei (Conrad) —........0000000000... -.--

Turritella andersoni, n. sp. -....2.02222..22eeeeeee oe Ne Bee ee x
Turritella uvasana Conrad .....0.0....022222-200-- ---- hee: aw x
Turritella buwaldana, n. sp. -...2-.22220222.... Nor mac iee 2s x

The species formerly identified in collections made from this
locality and from the Marysville Buttes as Trochocyathus striatus
Gabb proves to belong to the genus Balanophyllia according to Mr.
John Nomland, who has made a very careful study of West Coast
fossil corals. The species found south of Mount Diablo, whieh has
been described by him under the name of Balanophyllia variabilis,
appears to be larger, longer and more uniformly horn-shaped than
the form, from the Marysville Buttes, which as a rule suddenly en-
larges in the upper two-thirds of the corallum. The cross-sections
of the two corals appear to be identical. The differences cited may
be varietal at least. The true Trochocyathus striatus appears to
range through both the Rimella simplex zone and the Balanophyl-
lia variabilis zone, while Balanophyllia variabilis ranges through the
two upper zones and does not appear in the Rimella simplex zone.
The absence of several species characteristic of both the Siphonalia
sutterensis zone above and the Rimella simplex zone below are the
principal characteristics of this fauna. In other words, this zone
is transitional between the second and the uppermost zone of the
Tejon group.

Taken as a whole, the 2600 feet of the Tejon south of Mount
Diablo may be divided into three main divisions, the lowermost, the
middle consisting of the three bluffs and their intervening strata,
and the upper. Within these are recognized several faunal zones:
(1) Turbinolia zone; (2) Rimella simplex zone; (3) Balanophylha

variabilis zone.

TrsJon Locaniries oF 1911 SUMMER SCHOOL
All localities in the following list are in the Tejon group, Mount
Diablo Quadrangle, Contra Costa County, California.

380

University of Californa Publications in Geology [Vor. 9

(Twp. 1 South, Range 1 West, Mount Diablo Base Line and
Meridian, unless otherwise specified. )

106.

108.

124.

148.
342,

469.

470.

471.

472.

475.

476.

701.

703.

Near SE corner of SE 4% of Sect. 11. Summer School 1911. No. 30.
Coll. B. L. Clark.

North of center of SW % of Sect. 11, NE of Wall Point, elevation
about 1400 feet. S.S. 1911. Coll. B. L. Clark.

Near NE corner of SW % of Sect. 33, Twp. 1 North, R. 1 W, on SW
side of creek running to northwest, elevation 575 feet. S. S. 1911.
No. 677=1418.

NE 4% of Sect. 4, near Chico-Tejon contact. S. S. 1911. No. 682.
SW % of Sect. 3, in Pine Canon.

Near middle of SE % of Sect. 21, elevation 1350 feet, on north side
of ridge in Riggs Canon. SS. 8S. 1912. No. 1321 R. E. D. Coil.
R. E. Dickerson.

NE 4% of NW % of Sect. 21, elevation 1550 feet on Cave Point ridge.
8. 5.1912. No, 1817 R. E. D. Coll. R. E. Dickerson.

NW % of NE \% of Sect. 20, on first spur to east of saddle between
Oyster Point and Cave Point. S. S. 1912. No. 1008 Clark. Coll.
By iy Clark

SW % of SE % of Sect. 22, elevation 1050 feet, near coal mine.
S. S. 1912. No. 1402 Kew and No. 1501 Buwalda. Colls. J. P.
Buwalda and Wm. Kew.

Middle of range line between Sects. 15 and 16, elevation 1600 feet.
S. S. 1912. No. 1810 R. E. D. Coll. R. E. Dickerson.

SE corner of NW % of NW % of Sect. 22, elevation 1350 feet, just
above saddle in ridge, south of house and east of road. S. S. 1912.
No. 1404 Kew. Coll. Wm. Kew.

NE % of SE % of Sect. 22, elevation 1100 feet, about 150 feet above
junction of east branch of creek above house, with creek running
east from camp. S. S. 1912. No. 1519 Buwalda. Coll. J. P.
Buwalda.

SW % of NW % of Sect. 22, elevation 1200 feet, in little wash near
creek, below 1250-foot hill. S. S. 1912. No. 1406 Kew. Coll.
Wim. Kew.

NW corner of SW % of SW % of Sect. 22, elevation 1050 feet, on
road. S. 8S. 1912. No. 1407 Kew. Colls. Kew and Dickerson.

NE 4% of NW 4% of Sect. 21, elevation 1500 feet, on top of Cave Point
Ridge to SE of summit. S. S. 1912. No. 1339 R. E. D. Coll.
R. E. Dickerson.

NW \% of NE % of Sect. 27, elevation 1100 feet, about 200 feet up hill,
SE of coal mine. S. 8. 1912. No. 1120 Stoner. Coll. R. Stoner.

NE ¥% of SE % of Sect. 17, elevation 1850 feet, on ridge between
Windy and Cave Point. S. 8.1912. No. 1100 Stoner (July 4, 1912).
Colls. R. EH. Stoner, W. English and J. C. Merriam.

NE % of NW % of Sect. 13, elevation 1750 feet, on N side of Black
Hills, W of Wall Point. S. S. 1912. No. 1336 R. E. D. (Supple-
mentary S. S. Map). Coll. R. E. Dickerson.

SE % of SE % of Sect. 11, on road east of 2018-foot hill. S. S. 1912.
No. 1336 R. E. D. (Supplementary Map). Coll. R. E. Dickerson.

1916]

704.

705.

706.

714.

715.

717.

718.

(a)

726.

Dickerson: Tejon Eocene of California 381

Twe. 1 Souru, Rance 1 East

NE 4% of NW ¥ of Sect. 20. S. S. 1912. No. 1326 R. E. D. Coll.
R. E. Dickerson.

NW % of SE \% of Sect. 22, elevation 1300 feet, near top of ridge,
east side of Riggs Cafon opposite Oyster Point. S. 8. 1912. No.
1510 Packard. Coll. HE. L. Packard.

NW % of SE \% of Sect. 22, elevation 1000 feet, east side of Riggs
Canon near road running east from canon. S. S. 1912. No. 1508
Packard. Coll. E. L. Packard.

On east side of Cave Point in the basal stratum of the Tejon group.
S. S. 1912. Coll. R. HE. Dickerson.

SE ¥% of SE \% of Sect. 17, elevation 1900 feet, on S side of Cave Point,
a little east of 2100-foot hill. S. S. 1912. No. 1007 B. L. Clark.
Coll. B. L. Clark.

NE \% of SE % of Sect. 21, elevation 1250 feet, Riggs Canon, N of
Oyster Ridge. S.S. 1912. No. 1328 R. E. D. Coll. R. E. Dickerson.

NE 4% of NE % of Sect. 21, elevation 1250 feet, Riggs Canon, about
14 mile N of Oyster Point Ridge. S. S. 1912. No. 1329 R. E. D.
Coll. R. E. Dickerson.

NW % of NW % of Sect. 26, elevation 1450 feet, % mile NE of 1594-
foot hill, on ridge NW of divide. S. S. 1912. No. 1422 Wm. Kew.
Coll. Wm. Kew.

SW % of SE \% of Sect. 22, elevation 1950 feet, 150 feet E of road.
S. S. 1912. No. 1518 Packard. Coll. HE. L. Packard.

NE \% of NE % of Sect. 27, elevation 1000 feet, 50 feet above creek on
right bank, 150 feet from section fence. S. S. 1912. No. 1533
R. E. D. Coll. R. E. Dickerson.

NE % of NE \ of Sect. 27, elevation 1250 feet, on ridge leading N
from 1594-foot hill. S. S$. 1912. No. 1417 Kew. Coll. Wm. Kew.
NW % of SE % of Sect. 22, elevation 1300 feet. S. S. 1912. No. 1349

R. E. D. Coll. R. E. Dickerson.

On section line between Sections 15 and 16, near middle of line, eleva-
tion 1600 feet, on W hillside about 300 yards SE of road at the
divide between Riggs Canon, W of road, N of Oyster Point Ridge.
S. S. 1912. No. 1419 Kew. Coll. Wm. Kew.

SE % of SE \% of Sect. 21, on EF line of section, elevation 1250 feet,
Riggs Canon, W of road, N of Oyster Point Ridge. S. S. 1912.
No. 13820 R. E. D. Colls. E. Brainerd and R. E. Dickerson.

NE % of SE \% of Sect. 21, elevation 1250 feet, Riggs Canon, W of
road and N of Oyster Point Ridge. S. S. 1912. No. 1337 R. E. D.
Coll. R. E. Dickerson.

Center of NW % of Sect. 21, elevation 1400 feet, 100 feet above
bottom of canon, and 100 feet above base of second bluff, between
Cave Point and Oyster Point. S. S. 1912. No. 1341 R. E. D. Coll.
R. E. Dickerson.

SE corner of NE % of Sect. 21, elevation 1050 feet, Riggs Cafion,
W of road, at intersection of creek between Oyster Point and Cave
Point and the main creek. S. S. 1912. No. 1316 R. E. D. Coll.
R. E. Dickerson.

SW % of SW % of Sect. 22, elevation 1100 feet, Riggs Cafion, 250

382 University of California Publications in Geology [ VoL. 9

feet W of road and E of Oyster Point. S. S. 1912. No. 1343
R. E. D. Coll. R. E. Dickerson.

730. SE 4% of NW % of Sect. 21, elevation 1350 feet, 100 feet above base
of second bluff, N of Oyster Point. S. S. 1912. No. 1342 R. E. D.
Coll. R. E. Dickerson.

731. SW % of SE % of Sect. 22, elevation 900 feet in creek bottom. S. S.
1912. No. 13848 R. BE. D. Coll. R. E. Dickerson.

732. Center of S % of Sect. 22, elevation 1400 feet, E side of Riggs Canon,
just below top of hill on ridge leading south. S. S. 1912. No. 1409
Kew. Coll. Wm. Kew.

733. Middle of E half of SE % of Sect. 22, elevation 1150 feet on E side of
Riggs Canon on ridge above barn in canon. S. S. 1912. No. 1410
Kew. Coll. Wm. Kew.

734. SE 4 of SW ¥ of Sect. 22, elevation 1200 feet, E side of Riggs Canon,
above coal mine on top of ridge SW edge of hill. S. S. 1912. No.
1412 Kew. Coll. Wm. Kew.

745. NE corner of Sect. 20, on ridge running S from Cave Point, 100 feet
above base of second bluff. S. S. 1912. No. 1340 R. E. D. Coll.
R. E. Dickerson.

756. NW % of SW ¥ of Sect. 22, elevation 1250 feet in white bluff on road
¥% mile above camp. S. S. 1912. No. 1418 Kew. Coll. Wm. Kew.

769. NW \% of NE %& of Sect. 21, nearly due west of house, elevation 1300
feet. S.S. 1912. No. 1205 Stoner. Coll. R. C. Stoner.

Twe. 1 SourH, RANGE 1 West

1412. Near NE corner of NW % of Sect. 10, on S side of Pine Cafion, eleva-
tion 900 feet.

1415. SE % of NE ¥% of Sect. 10, elevation about 450 feet, N of Wall Point.

1417. NE corner of NW % of Sect. 10, near head of Pine Cafion, elevation
850-900 feet. S. S. 1911. No. 353.

1418=124.

1420. Near center of NE \% of Sect. 10, elevation 750 feet, in basal member
of Tejon.

1421. SE corner of NE \% of Sect. 32, Twp. 1 North, Range 1 West, on ridge
E of Pine Cafion, elevation 650 feet. S. S. 1911. No. 673.

1427=108.

1428. On E line of SW ¥ of Sect. 11. S. S. 1911. No. 53.

1429. On E side of road near SW corner of SW % of Sect. 12. S. S. 1911.
No. 29.

1430. SE 4% of Sect. 11, on N side near top of 2018-foot hill in basal member
of Tejon. §S. 8. 1911. No. 57.

1432. Near S line of NW \% of Sect. 11, near head of Pine Canon, elevation
about 1250 feet. S. S. 1911. No. 25.

1489. On S side of Pine Canon on branch road crossing over ridge to Dan-
ville about 200 feet above bottom of Pine Cafion on W line of S W
% of SW \% of Sect. 3. S. 8. 1911. No. 329.

THe TEJON Group NortrH or Mount DIABLo
STRATIGRAPHY

The Tejon north of Mount Diablo is a strip which is on the
average a mile in width and several miles in length. It consists of

1916] Dickerson: Tejon Eocene of California 383

a thick basal conglomerate resting unconformably upon Chico-Mar-
tinez rocks, white to dull red sandstone with subordinate shale beds,
and three coal seams interbedded with soft shales and white sand-
stones. Its upper limits have not been certainly discovered, but
there is a sudden change in lithology north of the village of Somers-
ville which may mark a division line between it and the overlying
brown carbonaceous sandstones of possible Oligocene age.

The Martinez group in this vicinity is represented surficially by
a strip averaging one-quarter of a mile wide which extends from
lower Oil Creek westward for four miles. Its west end is terminated
by a cross-fault, while its eastern end is cut off by the Tejon con-
glomerate.

Throughout the area studied there is a constant difference in
strike between the Martinez and the Tejon. This is generally ten
degrees, and in lower Oil Canon it is much greater. This difference
in strike causes the Tejon conglomerate to rest upon a stratum of
hard Martinez sandstone at one locality and upon soft Martinez
shales at another. This accounts for a very irregular Martinez-
Tejon contact.

The dip of the Martinez throughout the field is greater than
that of the Tejon. The basal Tejon conglomerate, which is from
ten to twenty feet thick, rests upon the Martinez sandstones and
shales and forms a well-defined bed for over four miles in length. It
consists of very coarse pebbles and boulders, which make it easily
separable from the sandstones of the Martinez. The pebbles and
boulders are in most places quartzose, but fragments of fossiliferous
limestone, and sandstone and igneous rocks also occur. Nucula
truncata, Cylichna costata, Modiolus cylindricus(?), Dentaliwm
cooperii, and molluse-bored boulders which resemble very closely the
pholad borings on the Martinez-Chico contact described below, have
been obtained from limestone and sandstone boulders imbedded in
the conglomerate. Either the Chico or Martinez groups supplied
this material, or possibly both may have contributed to this basal
Tejon, as these species are limited to the upper Cretaceous and the
Eocene on this coast.

The evidence of unconformity between the Martinez and the
Tejon groups in the region north of Mount Diablo is based (1) upon
areal mapping of the beds containing characteristic faunas of these
groups, (2) upon variation of strike at the contact, (3) upon varia-

a

tion in dip throughout the area studied; (4) upon the presence of

Sea Levé/

384 University of California Publications in Geology [Vo. 9

a conglomerate which marks a very decided change in sedimenta-
tion at the base of the Tejon. (See Fig. 3.)

Oi! Coon ~

Fig. 3. North-south section showing relations of Chico, Martinez and
Tejon in the region north of Mount Diablo, near Stewartville.

FAUNA

The principal fossiliferous horizon in the Tejon north of Mount
Diablo occurs above the coal strata in the vicinity of the old coal
mining village, Somersville. Stanton®® described this locality as
follows :

The contact between the Chico and the Tejon was not found exposed at
any place near the coal mines east of Clayton, but it is evident that the coal
beds are not far above the base of the Tejon. Gabb reports the occurrence
of Cucullaea mathewsonii and Fasciolaria laeviuscula in the “intermediate
beds” beneath the coal near Clayton, thus indicating a horizon much better
represented by fossils near Pacheco, Benicia, and Lower Lake. At Summers-
ville, one of the coal-mining villages east of Clayton, an undescribed species
ef Corbicula occurs abundantly in a layer beneath the lower coal bed.

The beds associated with and immediately overlying the coal consist
mostly of light-colored, rather coarse, friable sandstone, 400 or 500 feet in
thickness. In most of the exposures examined they are fossiliferous only in
the upper part, where they contain a typical Tejon fauna like that described
from Fort Tejon. Probably the lowest of these fossiliferous horizons above
the coal is exposed in a low hill just west of Summersville and south of the
cemetery, in sandstones not mcre than 100 feet above the principal coal
bed mined there, and perhaps 300 feet above the base of the sandstones.
The following species have been identified in the collection from this place:

Modiola ornata Gabb Pectunculus sagittatus Gabb
Venericardia planicosta Lam. Cardium cooperi Gabb
Lucina gyrata (Gabb) Solen parallelus Gabb
Corbula parilis Gabb Meretrix uvasana Conrad?
Tellina hoffmaniana Gabb Corbula hornii Gabb
Turritella uvasana Conrad Amauropsis alveata (Conrad)
Solarium cognatum (Gabb) Rimella macilenta White
Ficopsis remondi Gabb Fusus californicus Conrad

Aturia mathewsoni Gabb?

The Tejon strata, dipping strongly northward, may be traced almost
continuously from Summersville west toward Clayton for three or four

39 Stanton, T. M., The Faunal Relatons of the Eocene and Upper Creta-
ceous on the Pacific Coast, 17th Annual Report, U. S. Geol. Surv., pp, 1011-
1059, 1896.

1916] Dickerson: Tejon Eocene of California 385

miles, and fossils evidently belonging to the same fauna with those named
above are abundant at several places at horizons apparently all somewhat
above that at Summersville and ranging through a thickness of several
hundred feet. One of the most prolific of these localities is on a hill south
of the Clayton-Summersville road and about 2% miles N 35° E of Clayton,
where the following species were obtained:

Leda gabbi (Conrad) Fusus diaboli Gabb

Nucula (Acila) truncata Gabb Perissoiax blakei (Conrad)
Crassatella grandis Gabb Pleurotoma (Drillia) raricostata Gabb
Crassatella uvasana Conrad Bela clathrata Gabb

Tellina hoffmaniana Gabb Fusus occidentalis Gabb

Meretrix uvasana Conrad Pleuroioma, sp.

Lunatia nuciformis Gabb Ficopsis remondi Gabb

Lunatia hornii Gabb Conus remondi Gabb

Galerus excentricus Gabb Olivella mathewsoni Gabb

Solarium cognatum (Gabb) Cylichna costata Gabb

At other localities a little farther west, where smaller collections were
made, many of the same species were obtained, together with a few others,
such as—

Venericardia planicosta Lam. Dentalium stramineum Gabb
Mysia polita Gabb Tritonium hornii Gabb
Neaera dolabraeformis Gabb Ficopsis hornii Gabb

Gadus pusillus Gabb Megistostoma striata Gabb

The fauna represented by these lists is clearly the original Tejon fauna
that occurs in the neighborhood of Fort Tejon, New Idria, and elsewhere
along the coast ranges to Washington. Its Eocene character has been
recognized by Conrad, Marcou, Heilprin, White and others.

Dr. Stanton evidently studied the Tejon in the vicinity of Clay-
ton and ‘‘Summersville’’ but not south of Stewartville. In the area
along the Clayton-Somersville road the Tejon has been brought in
contact with the Chico by a strike or oblique fault which has faulted
out all the Martinez and about 2000 feet of Tejon strata beneath
the coal horizon.

The collections in the California Academy of Sciences from this
vicinity contain the following species:

List OF SPECIMENS FROM BALANOPHYLLIA VARIABILIS ZONE, Nortu or Mount
DIABLO

Spatangus(?) pachecoensis Pack.......-.......22..22222-..-----------+-- ar erren x
Balanophyllia variabilis Nomland.................00-.0002-20002--------------
Flabellum californica Vaughan..........22220002220-2220--eeeeeeeeee ee
Stephanophyllia californica Nomland...
Turbinolia, dickersoni INomlam Giiccccoccce occ ococeccceccccccccccescntecacessesence =-2=
Trochocyathus striatus (Gabb) ...00..0000000000222222ee eee cece eee eee eee "
Trochocyathus stantoni Vaughan ....0000..20002202202000..eceeeeeeeeeeeeeeee
FACIL AS ADD LAN eter SD) se neneee eee een eee ee

386 University of California Publications in Geology | Vou. 9

List or SPECIMENS From BALANOPHYLLIA VARIABILIS ZONE, NortH oF Mount

DraBLo—/(Continued) 259 261
Corbullay spar lisis Giallo Wyss cae eee cesar eee eee x x
(Ovo ed aybukeYse da\oy angie lie Cye21] 0) 0yy esse ee ee x x
COkrolibboar reraxey eyes abt (E¥2)) 00) ape ee ee eee x x
@rassatellites: wvasama, Comma si 2ee cece cece erent eee eee x ae
Diplodonta, Parise (CG apby eeceeesssecereccseeee sees sce eeereneeenenenee cee x
Glycimeris ‘Sacittatuis (Grav Di) ees oc area eee <
Media) Sab Wie COMA, Seer sccce te eee ee 4
Meda vaderensis: Dickens omy sic sece cea ce cc ceesce aces eeeeecec ee seneeere a aeeaees x
Mieretrix: Worst (Gravity cesses ae nee eee nese renner x x
Menetrixs ovalis, (Gia Dip csss2sve sccee ccs cece eae ce eet cere ee eee x
Meretrix tejonensis Dickerson ...............22222..22-2-c-ce-eceeeeeeeeeeeeeee x aoe
IANS Ken ed gs eh ty, Fake] Oop ANG eh 910) KGL see Se a eee x
Solemn paral eu si Gal byes ee oe eee x int
Spisulla: miennriana Packain dit csccssscscceseess onscreen eens oeeene ee anee eaencem x ae
Tellina sutterensis Dickerson x
TellimasjolaenSis wns: Spy se cessszcense sec oes omneeeeen ees eee oe ree x x
TNellina: Foaqminensis’ Ammoldh sy eee eee x Bey
AWD DUrivoteehgnn es ooKoy a6 bl KCL 0) oye eae ere Ne rege ee ee x
Venericardia planicosta hornii (Gabb) —2..0222200000020 22022222... x
IBY Vay bh coke tee was boeysyohonl, (Ce 0)0) | see ee x
ACLAC OM) MVOOG Yad; Mls SDs cesreecescsecceececcssecensacsesesecseeeses ecees seeeeeereesueuyanes x
Arehitectoniea seo xmatal = Cia eset eee ee eee eee eee x x
Amauropsis alveata (Conrad) x
Bullaria hornii Gabb .....
Cylichna costata Gabb x
Cancellaria stantoni Dickerson
WOmUSs Ci TiO rem Ga ec ee eee x
(Ofaabisy releranvapaleitite (Cie yoy 0) se me x
Drala earl COS ter tae Gre 0 Dip ce ee e x eee
Hciliamperkimsiamean | (COO WCs) ime e cere enna ee esere ee ee eens een es
Fusinus mathewsonii Gabb x
VSLDiESH GaN DSI gals og isl OLN Oleratay Osa meen eo rae n anes eee ee oe x
IICOPSIS: Temondii “Gaby Foca c ec cc eee cce ne ccee ee eee x
Mesistostomiay Striaital, Gea pices asec acre ree x
Natica, hannmibali Dickerson oesseceecceseeeseree eee eee eee x
PenissolaxiblakerrGConmads)) sc seca ees See x x
aSeiro aes keh otsbaleeyl bb c(eyetzh (C421 010) apg eee es x
Tumeriitelil as CW, le (SID syesecascttes cases ea eete en eee nee ee x
Murnitellawuvasanal (COT ad ee seeeee recess ease een eee ee x
Turritella uvasana bicarnata Dickerson .... x
EINUBTIET SES DO nse Bowes oe ee a eee eee ree ar en
CAG OTT FS Pee a ta ee ace | x

Cal. Acad. Sci. Locality No. 259. Mount Diablo Quadrangle, Tejon Group.
Two miles N 60° E of Clayton, about 100 feet (stratigraphic) above the
coal seam and 100 feet below a shale bed. Colls. C. L. Moody, J. O. Nom-
land and R. E. Dickerson.

Cal. Acad. Sci. Locality No. 261. Mount Diablo Quadrangle, Tejon Group.
One fourth mile south of Somersville cemetery, in sandstone about 100 feet
above coal seam. Colls. B. L. Clark and class, and R. E. Dickerson.

1916] Dickerson: Tejon Eocene of California 387

This fauna evidently represents the Balanophyllia variabilis zone
on the northern limb of the Mount Diablo Anticline.

IonE FORMATION OF CALIFORNIA

One of the numerous problems of C:lifernia geology is the cor-
relation of the Tertiary of the Sierra Nevada with that of the Coast
Ranges. Many geologists since the time of Whitney have written on
the age of the Auriferous Gravels and the associated formations, but
the ages of these formations are still in question and their correlation
with the marine deposits of the coast ranges is unproven.

While collecting during the past four years for the Department
of Palaeontology of the University of California, the writer has had
opportunity for the study of the relationship of the Ione of the
Sierra Nevada with the marine Eocene of the Coast Ranges. His
conclusions are based upon visits to five typical Ione localities, viz..
Marysville Buttes, Sutter County, California; vicinity of Oroville
South Table Mountain; Merced Falls; vicinity of Bear Creek, Mer-
ced County; and the type locality near the town of Ione in the Jack-
son Quadrangle.

Conclusions from this sturiy are, that the Ione is, in part at least,
marine and of Tejon-Eocene age. Marine fossils have been found
in the upper portion of the Ione formation in the four localities
visited. Apparently the same faunal zone, the Siphonalia sutter-
ensis*® zone, is represented in these five places.

In the study of the Eocene of the Marysville Buttes the writer’s
conclusion was that ‘‘the supposed marine Ione of Marysville Buttes
is evidently Eocene.’’ In the ‘*Note on the Faunal Zones of the
Tejon Group,’ the strata beneath the Older Basalt of Oroville South
Table Mountain, which Lindgren mapped as Ione, were correlated
with the Eocene of the Marysville Buttes. Several of the fossils
obtained from the strata beneath the Older Basalt were identical
with those of the Marysville Buttes. After visiting these two
localities the writer was inclined to the belief that the Ione and
Tejon had been confused in both these places. Conclusive evidence
has recently been obtained in the type locality of the Lone which
demonstrates that the Ione is merely a loeal facies of the Tejon-
Hocene.

40 Dickerson, R. E., Fauna of the Eocene at Marysville Buttes, California,

Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, pp. 257-298, 1913. Note on the
Faunal Zones of the Tejon Group, Univ. Calif. Publ. Bull. Dept. Geol., vol. 8,

p. 23, 1914.

388 University of California Publications in Geology (Vou. 9

During a recent visit to the Marysville Buttes the writer obtained
evidence that the Ione as mapped in the Marysville Folio*! consists
of Chico Cretaceous, Tejon Eocene, and a formation made up of
rhyoltic tuff, conglomerates, and thin flows of igneous rock evidently
derived from vents which are now represented by volcanic necks
designated on the map as ‘‘Nr.’’ This last formation rests with
marked unconformity upon the two older terranes mentioned and is
in turn unconformably overlain by andesitic flows of a later period.

THE EOCENE OF OROVILLE SOUTH TABLE MOUNTAIN
LOCATION

In a recent paper entitled ‘‘The Fauna of the Eocene at Marys-
ville Buttes,’’ the writer*? recognized a new faunal zone in the Tejon
eroup of California and identified the supposed marine Ione of the
Marysville Buttes as Tejon Eocene. The study of the sediments be-
neath the Older Basalt has resulted in the recognition of these sedi-
ments as Tejon Kocene of the same age as the uppermost Eocene
of the Marysville Buttes, the Siphonalia sutterensis zone. These
sediments are littoral deposits, the inshore equivalents of the sedi-
ments deposited in the deeper waters of the Marysville Buttes region
during Eocene time.

The Eocene strata outcrop near the town of Oroville on the
west side of the Sacramento Valley. These strata have been previ-
ously regarded as Miocene and were mapped as the lone Forma-
tion by Lindgren. The principal fossil localities are located about
two and one-half miles north of the town on the south side of Oro-
ville South Table Mountain, a flat-topped hill, 1050 feet in eleva-
tion. (See Plate 43, Figs. 1 and 2.) The beds in which the fossils
are found are nearly horizontal. In some places they have a dip
of about one degree to the southwest. They rest upon rocks of
Chico age and upon the bedrock complex of the Sierra Nevada, and
are capped by a basaltic lava flow which varies in thickness from
fifty to two hundred feet. Oroville Table Mountain and the South
Mountain, with other and smaller flat-topped hills in the vicinity,
are remnants of an extensive flow which, according to Turner, came
from a point about twenty or thirty miles to the east. The name
Older Basalt was given to this lava on the geological map of the

41 Lindgren, W., and Turner, H. W., Marysville Folio, U. S. Geological
Survey, Folio 17, 1895.

42 Dickerson, Roy E., The Fauna of the Eocene at Marysville Buttes, Cali-
fornia, Univ. Calif. Publ. Bull. Dept. Geol., vol. 8, pp. 257-298, 1913.

1916] Dickerson: Tejon Eocene of California 389

Bidwell Bar Folio, just east of this area. Oroville South Table
Mountain is about thirty miles northeast of the Marysville Buttes,
which are located in the center of the Sacramento Valley.

HISTORICAL

The region north of Oroville has been described in several of the
reports of the California State Mining Bureau** in connection with
the extensive hydraulic mines of that locality. Diller** and
Turner* have described portions of it and Lindgren,*® in a recent
paper summarizing all the previous work, has given detailed
descriptions of several mines of this area and published a geological
map of a portion of the Chico Quadrangle. In this paper, the strata
beneath the Older Basalt of South Table Mountain are mapped as
Tone.

The first determinative fossils found in the sedimentary beds
beneath the Older Basalt were obtained by Mr. O. W. Jasper, a
mining engineer, who sent a collection of marine fossils to the Uni-
versity of California from Oroville about fifteen years ago. He
described the locality as follows: ‘‘The collection of fossils referred
to were taken from a mine, . . . located at the south end
of South Table Mountain about two miles northeasterly from
Oroville. The tunnel from which the collection came was in about

ri |

2000 feet under the mountain. This collection contained Veneri-
cardia planicosta merrianu, Barbatia morsei, and two new species
which have since been found in the Eocene at the Marysville Buttes
and described as Turritella merriani and Siphonalia sutterensis.
Mr. Harold Hannibal collected fossils from the strata beneath the
Older Basalt in the spring of 1913. Mr. J. H. Ruckman and the
writer visited Oroville South Table Mountain in November, 1913,
made a brief study of the stratigraphy and collected fossils from
several localities. Professor J. P. Smith in 1909 in a short paper,
‘Salient Events in the Geological History of California’’, published

43 Preston, E. B., Eleventh Annual Report, California State Mining Bu-
reau, p. 155, 1895.

44 Diller, J. S., Tertiary Revolution in the topography of the Pacific
Coast, Fourteenth Annual Report, U. S. Geological Survey, pt. 2, p. 418, 1894.

45 Turner, H. W., The Rocks of the Sierra Nevada, Fourteenth Annual
Report, U. S. Geological Survey, pt. 2, p. 463, 1894; Further contribution to
the geology of the Sierra Nevada, Seventeenth Annual Report, U. S. Geo-
logical Survey, pt. 1, p. 541, 1896.

46 Lindgren, W., Tertiary Gravels of the Sierra Nevada of California,
Professional Paper 73, U. S. Geol. Survey, pp. 86-90, 1911.

390 University of California Publications in Geology [Vor, 9

in Science, suggested an Eocene age for the Ione and associated for-
mations.

STRATIGRAPHY

The base of the Eocene strata of South Table Mountain is exposed
in the old Miocene Hydraulic Mine, one mile north of Oroville. The
basal conglomerate, about twenty feet in thickness, rests upon Chico
rocks from which Mr. Ruckman obtained specimens of Trigonia
evansana, and Cucullaea, sp. Twenty feet of clay strata rest upon
this conglomerate. These two lithologic members were recognized
in the Rumble Mine, one-half mile northwest of this locality, at
County Hospital Hill, one mile west, and in the Dyer mining shaft,
two and one-half miles north of Oroville. <A study of the sediments
as exposed in the Dyer shaft and the south face of South Table
Mountain gives in descending order the following approximate

sequence :

Feet
(9) Older “basalt ye ete ew aaa 100 to 150
(Ess) PNovalefsauies ebb” Joreeyee yy ee ee 10 to 20

(7) Alternating sandstone, clay and carbonaceous shales.............. z 100

(6): Conglomerates 22. ek ee eee 50

(G5)) el MI Giese =(0} DESI amar c) Fta'se cee rede nee IA re SOS on ee 20

(4)" Yellow, tan’ “sandstonei 3.2. ee ee ee 100
(3) Dark gray shales interbedded with lignite containing fos-

siliferous strata, and thin-bedded fossiliferous sandstone 40

(OY MOUE nies aialay qypbue ts peeaneysi ounce ee es 20

Conglomerate resting upon Chico sandstone. 20

The remaining sedimentary series on the west side of Oroville
Table Mountain and South Table Mountain are composed of similar
sediments and are beyond doubt the same as those south of South
Table Mountain. Turner** reports finding Corbicula, sp. in these
strata at a point about one and one-half miles south of Pentz (form-
erly called Pence’s Ranch), where they rest upon Chico rocks which
contain a very abundant upper Cretaceous fauna.

The conditions of sedimentation in Morris Ravine and at the
Cherokee mine have been described admirably by Lindgren*® as

follows:
The well-known Cherokee hydraulic mine . . . is situated at the
north end of Table Mountain. . . . The bedrock of the channel mined

47 Turner, H. W., The Rocks of the Sierra Nevada, Fourteenth Ann. Rept.,
U. S. Geol. Survey, pt. 2, p. 463, 1894.

48 Lindgren, W., Tertiary Gravels of the Sierra Nevada of California,
pt. 2, p: 90) L901;

1916] Dickerson: Tejon Eocene of California 39]

is exposed for about 4400 feet, and in this distance the descent is 250
feet in a west-southwest direction. The form is that of a flat trough, the
bedrock rising on the south side 150 feet and on the north side 200 feet
and being laid bare throughout. . . . The bottom of the channel is on
the whole flat and 700 feet wide. The bedrock is very irregular in detail
and covered by large greenstone boulders. The elevation at the upper or
east end is about 1250 feet; at the lower end, at the hydraulic bank, about
1000 feet. This channel is not the bed of a main river but rather that of
a broad and steep gulch.

At the present bank the channel appears to turn southward and its
downward course is in doubt. The gravels at Morris Ravine are of a dif-
ferent character. The upper continuation of this channel is likewise in
doubt. It is believed that its source was somewhere near Yankee Hill,
where there are rich pocket mines, but there are many such deposits in the
immediate vicinity, especially near Oregon City, which could supply the
gold for concentration in the Cherokee channel. . . . Along the east
front of Table Mountain the basalt generally rests on bedrock at an eleva-
tion of about 1000 feet. A sharp Neocene slope of 500 feet in a mile
carries the bedrock down from Monte de Oro to Morris and Chambers
ravines, where several hydraulic and drift mines are located on bodies of
gravel once overlain by the basalt of Table Mountain. The elevation of the
bedrock at the diggings above the roadhouse on the point of South Table
Mountain is 750 feet. On this point an area of about 900 by 150 feet along
the rim has been washed. The rim rises 50 feet on each side, forming
a distinct shallow trough. The bedrock is greenstone. The bank is 100
feet high, showing 50 feet cf white sand with extremely well-washed
pebbles, mainly of quartz. The sand shows fine fluviatile stratification.
This is covered by 50 feet of yellowish clay in horizontal beds and this
in turn by basalt. From this point the bedrock remains near an eleva-
tion of 620 feet almost to the Yuba mine, where it sharply drops to 580
feet. Here there is a considerable hydraulic pit, showing a bank of fine
quartz sand with pebbles, underlain by yellowish material containing
many pebbles of diabase. . . . Just below this pit, at an elevation of
565 feet, the Yuba tunnel extends a few hundred feet in a _ westerly
direction. A slight incline carries it down to bedrock 20 feet below the
portal; at this point the bedrock still pitches into the hill.

A short distance north of the Yuba mine, on the road toward the
Goodall and Perkins mine, the Old Glory shaft is sunk 160 feet deep to
the greenstone bedrock, which lies at an elevation of about 510 feet and
slopes gently west. Coarse, partly angular greenstone gravel was found,
apparently containing little gold. The shaft is dry.

A large hydraulic cut has been made at the Goodall and Perkins
mine in the clays and fine gravels of the Ione formation, showing a lowest
bedrock elevation of about 560 feet. An incline sunk on the rim between
the Old Glory shaft and the Goodall and Perkins mine is said to have found
bedrock 100 feet lower than in the Old Glory.

No bedrock has been found east of these exposures. Heavy masses of
clay, with fossil wood, prevail in the south branch of Chambers Ravine.

There seems to be no large, well-defined channel in Morris Ravine,
but an even, rather sharp westward slope, which contained several gullies
in which coarser and finer gravel accumulated. They certainly do not
represent the continuation of the Cherokee channel.

392 University of California Publications in Geology [VoL. 9

As shown by Lindgren’s descriptions given above, the eastern
extent of the sediments mapped as Ione rest upon a very irregular
surface cut in the bedrock series. Several different stream channels
were recognized by him and he has clearly shown that the sediments
of Morris Ravine and the Cherokee mine are principally of
fluviatile origin. These sediments are the stream-laid deposits which
were being deposited at the same time as the marine strata along
the shore line a short distance further west.

The conditions in the eastern half and in the western half of
the sedimentary beds beneath the Older Basalt differ very decidedly.
No stream deposits were observed upon the western side, but the
strata appear to be continuous, whereas on the eastern side the
sediments were deposited in definite stream-channels. During Eocene
times there were several short, consequent, high-grade southward and
westward flowing streams which plunged quickly into the Tejon
sea, whose shore line must have been located about half-way be-
tween the south slope of South Table Mountain and Morris Ravine.
The approximate position of this strand line is indicated upon the
map (see fig. 4), which is after Lindgren.

FAUNAL RELATIONSHIPS

Mr. Ruckman and the writer obtained the following species
from two localities which were located about a mile north of the
Butte County Hospital.

List oF THE FAUNA FROM THE EOCENE OF OROVILLE SouTH TABLE MouUNTAIN

Turritella merriami Dickerson
Chrysodomus martini Dickerson

Acmaea ruckmani, n. sp.
Spisula tejonensis, n. sp. Packard

Turris perkinsiana (Cooper)
Turris inconstans (Cooper)
Drillia ullreyana Cooper
Drillia orovillensis, n. sp.
Murex (Ocinebra) nashi, n. sp.
Nyctilochus thunani, n. sp.
Cerithiopsis orovillensis, n. sp.
Turris monolifera (Cooper)
Surcula clarki Dickerson
Siphonalia sutterensis Dickerson
Neverita secta Gabb

Neverita globosa Gabb

Lunatia nuciformis Gabb
Nyctilochus diegoensis (Gabb)
Cancellaria stantoni Dickerson
Cordiera gracillima Cooper
Spiroglyphus, sp.
Architectonica, cf. cognata Gabb

Acila gabbiana, n. sp.

Area hornii Gabb

Barbatia, sp. a.

Barbatia morsei Gabb

Ostrea, sp. a.

Ostrea, cf. appressa Gabb

Venericardia planicosta merriami
Dickerson

Modiolus ornatus (Gabb)

Meretrix hornii Gabb

Placunanomia inornata Gabb

Phacoides cretacea (Gabb)

Leda gabbi Conrad

Tellina, sp.

Tellina longa Gabb

Teredo, sp.

Solen parallelus Gabb

Ea
Wy >) ©

Fig. 4. Geological Map of Oroville and Table Mountain, a portion of the
Chico Quadrangle. Adapted from Lindgren. Scale, 4% ineh—1 mile.

In a recent paper*® the writer discussed the faunal relationships
as follows (p. 24):

With the exception of the new species noted in this list, practically
all the forms occur in the fauna of the Marysville Buttes, and the most
characteristic of these species, Siphonalia sutterensis, Chrysodomus mar-
tini, and Drillia ullreyana are found at both localities. Another char-
acteristic feature of this fauna is the peculiar association of the Pleuro-
tomidae and Tritonidae. The striking difference . . . is the absence

49 Dickerson, Roy E., Note on the Faunal Zones of the Tejon Group, Univ.
Calif. Publ. Bull. Dept. Geol. vol. 8, p. 17-25, 1914.

394 University of California Publications in Geology [ Vou. 9

of such forms as Trochocyathus striatus . . . and Schizaster lecontei

. and of glauconite. In both of these faunas two of the commonest
Tejon species, Turritella uvasana and Amauropsis alveata, are missing.
The fauna of South Table Mountain Eocene is merely a different facies
than that of the Marysville Buttes and the absence of the coral, echino-
derm, and glauconite mentioned above is due to differences in bathy-
metric conditions. The South Table Mountain Eocene was deposited under
littoral conditions, while that of the Marysville Buttes was deposited in
considerably deeper water. The differences in lithology confirm this con-
clusion. These faunas are approximately the same age, but deposited under
quite different conditions.

The evidence stated above demonstrates the Eocene age of the
sediments beneath the Older Basalt, correlates these beds with the
Siphonalia sutterensis zone of the Marysville Buttes region and
shows their direct connection with the stream-laid deposits of the
Sierra Nevada. That the strata beneath the Older Basalt are iden-
tical with the Ione at its type locality in Amador County will be evi-

dent after its description.

THE IONE AT ITS TYPE LOCALITY.

LocaTION

The Ione formation from Oroville southward along the eastern
edge of the Great Valley exhibits many of the same characteristics
as were described at Oroville. A low westerly dip and an intimate
association with the Bench Gravels and the Deep Gravels of Lind-
gren and rhyolitie tuff of the Sierra Nevada are common to the
Ione from Oroville south to the vicinity of Fresno. The type
locality of the Ione is in the vicinity of the town of that name in
Amador County, California. The description of the type locality
is given below.

TurNeER’S DEescriprioN OF THE TYPE SECTION

Turner®’ recognized three lithologie members in this formation:
(1) the lower portion, a white clay; resting upon this (2) white or
red sandstone; and then (3) a light-gray clay rock. (See plate 44,
figs. 1 and 2.) He described it as follows:

Along the western border of the metamorphic rocks is a series of nearly
horizontally stratified, light-colored sediments, which were deposited in the
waters that covered the Great Valley at the time the older auiferous gravels
with interbedded pipe-clays accumulated in the river beds of the Sierra

slope. This formation attains its maximum development in the area of
the Jackson Sheet. The lower portion of the series, composed largely of

50 Turner, H. W., Jackson Folio No. 11, California, U. S. Geol. Surv., p. 2,
1894.

1916] Dickerson: Tejon Eocene of California 395

white clay, is well exposed around Ione, whence the formation takes its
name. Farther south the white clays are overlain by sandstone, above
which is a fine-grained clay rock. The lower, white clay is in places
quite free from grit and is used in making pottery. Other portions are
sandy. The formation contains iron-ore and coal seams. The sandstone
is used for building purposes. It is usually white, but at one quarry
a brick-red variety, colored by finely disseminated hematite, is obtained.
At other localities it is rusty and contains pebbles of white quartz, passing
into a conglomerate. A peculiar hydrous silicate of alumina occurs
abundantly in the sandstone in the form of cream-colored, pearly scales.

The clay rock occurring above the sandstone is light-gray—but usually
more or less discolored. The fracture is, as a rule, irregular, and the rock
frequently contains minute, tubular passages. Under the microscope it is
seen to be composed of fine particles of feldspar and fine discolored sedi-
ment, with occasional quartz grains. Analyses of two specimens gave 59
and 72 per cent silica and 4.8 and 1.6 per cent of alkali.

The succession of white clay, sandstone and clay rock may not be con-
stant throughout the entire area mapped as belonging to the Ione forma-
tion. It has been suggested that the white clay of the lower beds was
formed from rhyolitic tuffs, in which case eruptions of rhyolite must have
occurred at the beginning of the Ione epoch.

The thickness of the Ione formation is known partly by natural ex-
posures, partly by boring. In Jones Butte the strata, protected from ero-
sion by a lava cap, are 200 feet thick above Coal Mine No. 3. A boring
at the mine is said to have penetrated sandy clay to a depth of 800 feet
below the coal seam, which is 60 to 70 feet below the surface. Thus the
Ione beds appear to be more than 1000 feet thick at this point (see fig. 5).

To the east of Buena Vista Peak the series has a visible thickness of
600 feet. The table-land south and southwest of Buena Vista is chiefly
composed of the Ione formation, overlain by rhyolitic and andesitic tuff
and Neocene shore gravels. The lower clay occurs at the east base of
the table-land, and a patch of Ione sandstone caps Waters Peak, a little
farther east, which has an elevation of about 900 feet.

The relation of the sandstone to the clay rock is finely exposed on the
south side of the Mokelumne River, by the bridge north of Camanche.
Here the sandstone forms the lower part of the bank of the river. The
upper surface of the sandstone has a gentle westerly dip, and a little
west of the bridge reaches the Jevel of the river, which at this point is
about 175 feet above sea-level. East of the bridge it rises at an angle of
about 1°, reaching an altitude of 1000 feet on the flat ridge just north
of Valley Springs Peak. Along the banks of the Mokelumne west of
Lancha Plana this sandstone attains a thickness of more than 100 feet.

Turner, in describing the Neocene shore gravels, states their re-
lationship to the Ione as follows:

The most striking evidence of nonconformity, however, may be seen at
the red sandstone quarry three miles southeast of Buena Vista. Here the
Neocene shore gravels rest unconformably on the smooth waterworn sur-
face of the sandstone, which is red where quarried, but white at the
northern end of the exposure. Waterworn bowlders of the white sand-
stone may be seen in the gravel. Southwest of the quarry the ridge is

396 University of California Publications in Geology (Vou. 9

es

» SEER
Rar A
--\:-\----
ss
—
Sr ,
ey
=a
=
=
=
=
=,
a
a
ae
ae
eae,

\
IN
HET

_— Buena Vista

—o Peak
Say ie

S,

=)

Fig 5. Geological Map of a portion of the Jackson Quadrangle. Adapted from
the Jackson Folio. Scale, 4% inch—1 mile.

BC, Basement Complex; ng. Auriferous Gravels; ni, Ione Formation; nsg,
Neocene shore gravels; na, andesitic tuffs; grv, Pleistocene shore gravels; al,
alluvium.

1916] Dickerson: Tejon Eocene of California 397

capped-for a distance of more than a mile with the same gravel, which
half a mile from the quarry contains a layer of andesitic detritus. At the
extreme southwestern end of the ridge is a body of similar gravel, which
also rests plainly on sandstone of the Ione formation.

OCCURRENCE OF EOCENE FOSSILS IN THE IONE

All the localities described by Turner have been visited. At the
last-mentioned locality, ‘‘the red sandstone quarry three miles south-
east of Buena Vista,’’ the writer obtained Venericardia planicosta
merriamt, Meretrix hornii Gabb, Psammobia, ef. hornii Gabb, Crassa-
tellites, sp., Turritella merrianu Dickerson, Natica, sp., and Clavella,
sp. The Venericardia planicosta found here is the variety with the
obsolete ribs. All of these forms were collected from the sandstone
five to ten feet beneath the Neocene shore gravels. While the fauna
is a small one, it is typical of the uppermost, the Siphonalia sutter-
ensis zone of the Tejon. The sandstone member in this vicinity with
a dip of only one degree toward the west attains a thickness of 250
feet. It rests upon the clay, an altered rhyolitic tuff which is only
fifty to one hundred feet in thickness. This in turn rests upon the
steeply tilted eastward-dipping Mariposa slates of the bedrock series.
The same sandstone occurs on the hill east of Buena Vista Peak,
and with about the same thickness. A half mile east of the hill the
lower clay member becomes appreciably thinner and is only twenty-
five to fifty feet thick. On Waters Peak, one-half mile farther east,
the clay member and a good part of the sandstone member are miss-
ing and only the massive upper fifty feet of the sandstone member
is found resting upon the eroded surface of the Mariposa slates.

The third member, the clay rock recognized by Turner, appears
to the writer to be merely a decomposition product of a rhyolitic
tuff. This rhyolitic tuff rests directly upon the sandstone member
in the vicinity of Buena Vista Peak. This is confirmed by an ex-
amination of the strata as exposed in Jones’ Butte. A clay rock
was found resting upon the sandstone member. In certain places
this rock was found to be an unaltered rhyoltie tuff.

From the above description it is seen that this formation appears
to have been deposited by a sea which transgressed from the west.
Two or more of the three members of the Ione are very persistent
over the Jackson Quadrangle, the Lodi Quadrangle, the Sacramento
Quadrangle, and the Sonora Quadrangle and they can be readily
recognized by their lithologic characters, low westerly dip, and
stratigraphic position beneath the andesitic tuffs and upon the Mari-
posa slates or other members of the bedrock series.

398 University of California Publications in Geology [VoL. 9

RELATION OF THE AURIFEROUS GRAVELS TO THE IoNE ForMATION

Essentially the same relations as were found at Oroville® exist be-
tween the Auriferous Gravels in the vicinity of Ione and the Ione
formation. Along the Calaveras River three miles east of Stone
Corral the intimate relationship of the Auriferous Gravels to the
Ione is shown by the mapping in the Jackson Folio. Both rest di-
rectly upon the diabase of the basement complex and they are only
a quarter of a mile apart in one locality. The mapping in the vicin-
ity of Campo Seco shows a direct relation between the marine Ione
and the gravels. The Ione area at Mule Town two miles north of
Tone has all the characteristics of the Auriferous Gravels and might
have been mapped as such but for its evident close association with
the Ione a short distance further west. A direct connection seems
to exist between the marine lone and the stream deposits of the
Sierra Nevada. Probably short consequent high-grade streams
emptied into the Hocene embayment now represented by the lower
member of the Ione. Apparently the shore line passed through the
present sites of the towns of Ione, Buena Vista, and Valley Springs.

These facts show that the Ione is the marine or estuarine equiv-
alent of the Auriferous Gravels, stream-laid deposits of the Sierra
Nevada.

THE IONE FORMATION NEAR MERCED FALLS

Until these three members were studied at the type locality, the
relationship of the small area south of Merced Falls, which was
mapped by Ransome and Turner as Tejon, to the adjoining Ione tuffs
and clays was obscure. The clays, sands and tuffs exposed one mile
west of Merced are lithologically identical with those of the lower-
most member, and the red sandstone mapped as Tejon found here
is identical with that of the second or sandstone member of the Ione
of the type locality. The same condition evidently prevailed here
as in the area between Waters Peak and Buena Vista Peak, that is,
a deposition along the shore line of a rapidly transgressing western
sea. In this sandstone, casts of the Venericardia planicosta merriami
were found near the top. The authors of the Sonora Folio, Messrs.
Turner and Ransome,*” described this as follows:

51 Dickerson, R. E., Note on the Faunal Zones of the Tejon Group, Univ.

Calif. Publ. Bull. Dept. Geol., vol. 8, p. 23, 1914.
52 Turner, H. W., and Ransome, F. L. Sonora Folio, U. S. Geological

Survey, p. 2, 1897.

1916] Dickerson: Tejon Eocene of California 399

Tejon formation.—The only rocks referable to this period are a few
isolated patches of light-colored sandstone which occur capping some low
hills in the southwest corner of the quadrangle. South and southeast
of Merced Falls are two level-topped buttes capped by this sandstone,
which rests almost horizontally upon the nearly vertical edges of the
Mariposa slates. The basal bed is crowded with angular fragments of the
slate and with abundant pebbles of white vein quartz, while the upper
beds are composed of a light-colored quartzose sandstone with frequent
bands of small quartz pebbles. Marine fossils (Venericardia planicosta)
are fairly abundant in the upper bed at tne west end of the butte that
lies one mile south of Merced Falls. These sandstones are overlain to the
west by the light-colored sandstones of the Ione formation. The two series
are probably not absolutely conformable, as the Ione beds transgress onto
the rocks of the bedrock series farther north.

The above-mentioned sandstones, instead of ‘‘being overlain to
the west by the light-colored sandstones of the Ione formation,’’ are
in reality stratigraphically higher. These sandstones have been worn
away from most of this area and only a few residuals remain.

After this great erosion, andesitic tuffs and tuff breccias covered
all. During the Pleistocene and Recent time much of the andesitic
material has been removed, re-exposing the older rocks beneath.

THE IONE FORMATION IN THE VICINITY OF BEAR CREEK,
MERCED COUNTY

The region south of Merced Falls was first described by Blake®*
in the Pacific Railroad Reports. The exploration route was along
the old Fort Miller road from Merced Falls to Fort Miller. Blake
recognized the unconformity between the sandstone and the under-
lying slates and he figured two hills showing the characteristic
topography yielded by the middle member of the Ione.

His description of the country south of the Merced is as follows:

Merced river to Bear Creek, July 22, 18.3 miles.—After leaving the
Merced our route lay among numerous isolated hills with flat summits;
a group of which is represented in outline in the figure. These hills
were estimated to be about one hundred feet in height. They are formed
of horizontal strata, and are the remnants of a former plain, the inter-
mediate portions having been removed by denudation. The “cap rock” on
one of the hills was found to consist of a bed of conglomerate, chiefly
of quartz pebbles, underlaid by a bed of light-colored sandstone, and a
second stratum of conglomerate. A cylindrical object, like a log of
wood, was protruding two feet beyond this layer of sandstone, and it
proved to be a part of a fossil tree, with a cross-section like the figure.

It was somewhat flattened as if by pressure. Its outer portions had
evidently been bored into by worms, as cavities similar to those formed

53 Blake, W. P., Explorations and Surveys for a Railroad Route from the
Mississippi River to the Pacific Ocean, vol. 5, part 2, pp. 12-15, 1853.

400 University of California Publications in Geology (Vou. 9

by the Teredo were found filled in with sandstone. The whole mass was
highly charged with Peroxide of iron, which, indeed seemed to be the
chief constitutent.

We had now progressed so far toward the mountains that we were
no longer upon the broad plains of the great valley of the San Joaquin,
but were traveling along the foot-hills of the Sierra Nevada. Our route
from this point, southward to Fort Miller, lay nearly on the border of the
lower granitic ranges, which presented occasional opportunities for ex-
amining them, in connexion with the sedimentary foot-hills.

The first outcrop of any of the rocks of the granitic and metamorphic
series met on the survey was near Howard’s ferry on the Merced. At
that place extended outcrops of dark-colored clay slate were observed,
having a trend N 55° W, and an inclination of 70° toward the east.
In some places they appeared chloritic; and in others had the general
character of roofing slate. They were traversed in the direction of the
bedding, by quartz veins of great thickness, the white quartz contrasting
finely with the black slate. This place is only nine miles west from
Quartzburg, where several mining companies have erected crushers and
stamps for pulverizing the quartz and extracting the gold it bears. The
unconformability of the sedimentary sandstone formation with these roof-
ing and chlorite slates is strikingly shown in this vicinity, where streams
have cut so deeply as to expose both formations. The horizontal strata
rest upon the upturned edges of the slates, as is shown in the section.

The outcropping layers of hard sandstone were visible in the hills
on each side, the intermediate portion (between the hills) having been
removed by denudation. At the highest part of the outcrop of slates, a
quartz vein, five feet thick, stands out above the general surface, and forms
a wall-like mass of fragments. These being milk-white, contrast strongly
with the black slate on each side. This quartz has preserved the sur-
rounding slate from abrasion by currents of water, and thus it stands at
the summit of a little eminence.

Burns’ Creek.—A remnant of the former elevated plain of sandstone
formed a picturesque object near our route, and was sketched by Mr.
Koppel. It consists of a nearly circular disk of compact sandstone, ten
or fifteen feet thick, capping the summit of a round mound. Hills of this
character, of greater extent and elevation, are numerous for several miles
south of this point.

Bear Creek.--At Bear Creek twelve miles north of the Mariposa
river, a good natural section or vertical exposure of the strata composing
one of these flat-topped hills was presented. It consisted of a series of
beds of coarse and fine sandstone and strata of gravel and conglomerate,
which are represented in section, Chapter XIII. The whole elevation of
the hill was estimated to be about 150 feet. The following is the suc-
cession of the strata as observed from the top downwards to the level
of the creek. The thicknesses are given as they were estimated, and are
therefore, merely approximate. The letters refer to the section.

Section of the Strata at Bear Creek

Conglomerate
Sandstone seer ceee eee onesies esereeees
Conglomerate
Sandstone, fine

ars ory

1916] Dickerson: Tejon Eocene of California 401

g. Conglomerate of gravel, white and black quartz, and nodules

CORE Coke bred oYonavenisy eye VN Aas eee eee ee eee eee aoe eae ee 10 feet
f. Sandstone, showing diagonal stratification and one or two layers

Ea ST UV CL ec re re ery a PP ee ree Be sn Seek aE | ie
e. Sandstone, with a layer of pebbles. eee 3.”
d. Hard sandstone, thinly bedded; layers of pebbles towards the base..20 ”
c. Compact sandstone, with some small pebbles. ee. vied
b. Sandstone, with coarse grains and pebbles... i
EMO ANG SUOMC ge ase oe eo eae ee yeeeaeeee ey Pa ee a

The upper stratum is perfectly level on the top and free from soil;
a dwarfed bush or tree, here and there, is the only vegetation. The whole
surface appears fissured, or as if cracked by drying in the sun—precisely
as the soil is cracked during the dry season. This must have taken
place at the time of the deposition of the rock or soon after. On closely
inspecting the slight accumulations of fine gravel in some of the hollows
of the rocks, numerous very small but beautiful crystals of andalusite were
found. These did not exceed three-sixteenths of an inch in diameter, and
were seldom over one-eighth. They are translucent, but appear to be
worn and rounded by attrition.

Turner®* described these as a continuation of the same formations
found one mile south of Merced Falls. He described the igneous

rocks of this neighborhood as follows:

Along the east side of the valley to the south of the Merced River
is a plateau, the upper layers of which, where examined, are composed
of andesitic detritus mixed with ordinary sand. Some of the white under-
lying’ material may be of rhyolitic origin. At any rate the white material
at the edge of the plains just west of Daultons in Madera County is
rhyolite.

The region in the vicinity of Bear Creek was recently visited
by Mr. Chester Stock and the writer for the Department of Palae-
ontology of the University of California to search for remains of
Auchenia californica’? Leidy and other Tertiary mammals which

54 Turner, H. W., Geology of Sierra Nevada, Seventeenth Annual Report,
U. S. Geological Survey, part I, p. 683, 1896.

55 The various beds described above were searched thoroughly for marine
and land remains, but none were found. A point six miles southwest of
Indian Gulch on the Mariposa line would be at Burns Creek. How Whitney
could describe Burns Creek as a nameless tributary of Bear Creek is hard
to understand, because this creek is distinctly mentioned in the Pacific Railway
Report and was early known by that name. Leidy’s statement concerning
the label which accompanied A. californica is that the specimen was found
beneath the basalts at Table Mountain near Shaw’s Flat, Tuclumne County,
California. C. D. Voy who collected the specimen of A. californica may have
collected Venericardia planicosta merriami Dickerson at the locality six
miles southwest of Indian Gulch.

In the Geology of the Sierra Nevada (17th Annual Report, p. 683) Turner
states:

“In a paper on the auriferous gravels attention was called to an inter-
esting locality of vertebrate remains described by Professor Whitney as
being on a dry creek tributary to Bear Creek near the line of Mariposa
and Merced Counties. A search was made for this locality but no evidence
of such remains was found. Professor Whitney later informed the writer
that he himself had investigated the locality and had been unable to find it.”

402 University of Califorma Publications in Geology Vow. 9

were supposed to occur in this vicinity, according to Whitney. The
following notes were made incidentally.

The rocks recognized in the area are: (1) The Basement Com-
plex, the bedrock series; (2) The Ione Eocene of the superjacent
series; (3) Pleistocene (?) shore gravels (of Turner).

The basement complex consists of slates of probable Mariposa
age, amphibolite schists and associated granitoid rocks. The latter
rocks are well exposed in Burns Creek at the county line. Schists
and slates are in general found in the area northeast of the old
Fort Miller road, along which Blake and the other geologists of the
Pacific Railroad expedition journeyed. Several points in their
description were easily recognized, particularly a small butte capped
by Ione sandstone in the vicinity of Burns Creek, and figured in the
Pacific Railroad report. The slates and schists form an extensive
belt.

The middle or sandstone member of the Ione rests unconformably
on the slates and schists. It varies in thickness from 25 to 75 feet
in various portions of the field. Evidences of deposition along the
immediate shoreline were found. Distinct mud-cracks were seen
in the sandstone blocks on top of the butte northwest of the mouth
of Bear Creek Canon. The relations between the middle sandstone
member and the lower rhyolitie tuff member were well shown in an-
east-west section along Burns Creek near the county line. (See

figure 6. An eighth-mile south of the county line the middle

She

Teh 4K
Xa

Basement Complex £ocene Lone Pleistocene
VAm: 7
2S aa
Granitoid Rocks Tone Sondstone Ple/stocene
rH on Shore
eh Grave/s
Schist Ione rhyolite
Mill
Li

Fig. 6. Generalized section in vicinity of Burns Creek, showing relations between
Tone members and the bedrock series. (Drawn by Chester Stock.)

1916] Dickerson: Tejon Eocene of California 403

member rests directly upon the basement complex. An eighth of a
mile west of the county line the middle member rests upon the lower
member which consists of rhyolitie tuff. The accompanying seec-
tion shows this relation graphically.

The lower member is characteristically tuffaceous, although dis-
tinet beds of gravel occur within it. There are several lthologic
facies exhibited in this member, as follows:

(1) A fine-grained kaolinized ash.

(2) Red-brown tuff-breecia weathering to a red, which ocea-
sionally contains partially altered fragments of rhyolite.

(3) A conglomerate which consists of quartzose pebbles, schist
and slate fragments, along with a few rhyolitie pebbles, the whole
being in a rhyolitie ash matrix. This member has a low westward
dip throughout the field of three to four degrees, and apparently
underlies most of the valley border for a distance of six miles from
the old Fort Miller Road. This member is exposed in the lower
course of Burns Creek.

DEEP-WATER EQUIVALENT OF THE IONE AT MARYSVILLE BUTTES
STRATIGRAPHY

After a study of the Ione along the foothills of the Sierra Nevada
the writer recently made another brief visit to the Marysville Buttes
to study the Ione as mapped in the Marysville Folio.***

The occurrence of Eocene strata in the vicinity of the Marys-
ville Buttes®® has been described at length in a previous paper.

The stratigraphic relations were described as follows (p. 261) :

In general, the sedimentary beds dip away from the central core.
The only Eocene area which is mapped in the Marysville folio is a strip
about a mile and a quarter long by a quarter mile wide on the west
side of the buttes two miles east of South Butte. The Eocene in this
area is overlain by the Ione formation which has a dip of 15° W, while
the Eocene has in most places a dip of 35° to 40° W, strike N
90° W, although the dip is nearly vertical near West Butte Peak. The
Ione consists of gravels and sands, for the most part unconsolidated. Cross-
bedding is very common and intricate. These sediments were probably de-
posited on the EKocene as an alluvial fan. The Ione in turn is overlain
by andesitic mud flows—now firmly cemented—which dip to the west
about 4° to 5°.

An east-west section through West Butte largely adapted from the
Marysville Folio shows the following sequence on the west side:

55a Lindgren, W., and Turner, H, W., Marysville Folio, U. S. Geological
Survey, Folio 17, 1895.

56 Dickerson, R. E., Fauna of the Hocene at Marysville Buttes, California,
Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, pp. 257-298, 1913.

404 University of California Publications in Geology | Vou. 9

100 feet of green-gray sandstone and shale with limestone concretions
marking the upper limit of the Eocene.

300 feet of green-gray, glauconitic shale.

200 feet of massive, thin-bedded, buff sandstone.

100 feet of impure, gray limestone with thin strata of hard gray, medium-
grained sandstone.

600 feet of massive, medium-grained, yellow, non-fossiliferous sand-
stone in contact with the andesitic core.

Resting upon the Eocene are 500-600 feet of Ione gravels and sands.
The two uppermost Eocene members, which are very fossiliferous, can be
easily recognized in the field by the bright red, clay soil formed through
their decay. The limestone concretions which are sometimes yellow,
contain many small, dark green to black, rounded grains. When these
are carefully examined with a hand lens they are found to be foraminiferal
casts composed of glauconite. The green shales as well as the sandstone
also contain glauconite and foraminifers. The strata are lithologically
similar to certain horizons in the Martinez, but the character of the fauna
here compels us to abandon the notion that green glauconitic sandstone
and shale are absolutely indicative of the Martinez in the middle Cali-
fornia region. Glauconitic sandstone also occurs in the Tejon of the
Mount Diablo region.

On the east side of the South Butte the writer has mapped another
Hocene area which has about the same sequence as the above. Thin strata
of coal are reported by Watts and later by Lindgren and Turner, from the
lower portion of this section.

According to H. Hannibal some of the area south of South Butte
mapped as Ione is Cretaceous.

In the section given above the ‘‘100 feet of impure gray lime- -
stone with thin strata of hard gray, medium-grained sandstone’’ is
probably the upper member of the Chico Cretaceous, as fossils
Spisula ashburnerit (Gabb), Trigonia evansana Meek and Gyrodes
expansa Gabb were found in a stratum of sandstone at its base. The
‘*600 feet of massive . . . sandstone’’ is also Chico Cretaceous.

DESCRIPTION OF THE SUTTER FORMATION

Resting with marked unconformity upon the Chico and the
Tejon are 500-600 feet of strata which are composed chiefly of
rhyolitic ash, rhyolitice tuff-breccia, thin flows of rhyolite and con-
glomerate containing rhyolitic and quartz pebbles. This formation
is overlain by lava flows and mud flows which consist of andesitic
material. Evidence of a time-interval between these two volcanic
formations is given by a marked difference of dip between them
throughout the field. The materials in the Sutter formation were
derived chiefly from the rhyolitic voleanic rocks (mapped by
Lindgren as Nr), as the lava composing the thin flow noted above

1916] Dickerson: Tejon Eocene of California 405

is identical with this rhyolite and some of the boulders in the
conglomerate are likewise composed of this rock. The rhyolite areas
mapped are in close association with the Sutter formation as a rule.

One of the best exposures for study is seen on a ridge one mile
southwest of West Butte. The beds at this place cap the underly-
ing Cretaceous. The overlying beds dip 10° W, while the underlying
Chico strata dip 40° W. The strata are composed chiefly of what
appears to be a much altered rhyolitie tuff-breeccia which looks at
first sight to be a sandstone. This rock is light gray when
weathered and a dark gray on unweathered surfaces. It is com-
posed of very angular quartz grains, altered biotite and feldspar.
Gypsum commonly fills the joint planes and in places occurs be-
tween the bedding planes. Lenses of conglomerate occur interbedded
with this rock and two thin flows of igneous rock four to eight
inches in thickness were also noted.

Farther west on this same ridge, this formation is found in fault
contact with the Tejon at the top of a small divide crossed by the
county road. This divide is located one and a half miles § 50° W
of West Butte. The Sutter formation at this point has a dip of 22° W
and a strike of N 20° W. The beds vary locally, cross-bedding being
common. Besides the rocks described above, a light-gray tuff com-
posed of fine ash particles occurs here. The andesite is sharply
separated from the Sutter formation at this locality and it has a
dip of only 6° W. This same relation is seen in the 547-foot hill one
mile north. Similar relations between the Sutter and the underlying
and overlying formations were found south of South Butte. This
formation is named for its occurrence in Sutter County, California,
in what is now known as the Marysville Buttes (formerly Sutter
Buttes).

HISTORICAL GEOLOGY

The sequence of events which gave us the Marysville Buttes in
their present form appears to be as follows:

(1) The lowering of the continental margin and the deposition
of Chico Cretaceous strata by a transgressing sea from the west;
(2) a great time-interval during which this site was land; (3) sub-
mergence at the end of Tejon time which resulted in the deposition
upon the outer edge of the continental shelf of Eocene strata com-
posed of foraminiferal shales, the deep-water equivalents of the in-
shore Ione of the Sierran foothills; (4) uplift; (5) an intrusion of

406 University of California Publications in Geology Vou. 9

rhyolite and consequent upturning and faulting of Cretaceous and
Kocene strata and outpouring of rhyolitic flows and ash deposits
(the Sutter formation) upon these faulted and folded sedimentaries ;
(6) a period of erosion during which a large portion of the Sutter
formation was removed; (7) an intrusion into these older formations
mentioned above and outpouring of andesitiec materials from a great
central voleano; (8) a long erosion interval during which short
streams consequent upon the lava slope cut through the andesitic
lava into the softer underlying deposits. Of these deposits the soft-
est is the Sutter. The pass between the towns of West Butte and
Sutter City was cut in this material. The ‘‘secondary craters’’
deseribed in the Marysville Buttes Folio appear to be erosion valleys
formed in the Sutter formation by subsequent tributaries of con-
sequent streams.

In conclusion, there does not appear to be any formation in the
Marysville Buttes except the Tejon Eocene strata which could pos-
sibly be the equivalent of the Ione of the Sierran foothills. It has
been shown above that these Eocene strata are the off-shore
equivalents of the inshore Ione.

SUMMARY OF FAUNA OF THE SIPHONALIA SUTTERENSIS ZONE

The discovery of several new areas in which the Siphonalia sut-—
terensis zone was represented and large additions to the faunas
modify the previous conclusions of the writer concerning this zone.
Many of the forms which were thought to be characteristic have
been found at lower horizons and several! more species characteristic
of the middle and lower portions of the Tejon group are now re-
ported from this zone. The list of species obtained from this zone
is given below.

List oF SPECIES From LOCALITIES IN THE SIPHONALIA SUTTERENSIS ZONE

1853 1856 692 2225 2365
INOGOSAT 1s, SP a eces cca sc ee ee ee ee eee ate eee

Balanophyllia variabilis Nomland —..................... x x
Ta RS Ye ce reece eee ere eee eee ee ee ee ead 8
OL ae UL SD or core sore aeee case cece ae eee eee ee ne
Stephanophyllia californica Nomland_............... a ao x

Trochocyathus (?) perrini Dickerson..................
Schizaster lecontei Merriam ...................--.----------- = = ae
NCI aS a DLAs pile SP yy ecseren. casesesseeseeeseeeceecesseecen se eeaae x Pes x x
ENTE CAs LO ET TEM Gea DO pe eee eee x a ae x
Avicwla, pellucida, Gaby 22oc2sccce 2 2-ceceeecceeee-ceutcesesee x

x

1916] Dickerson: Tejon Eocene of California

407

List oF SPECIES From LOCALITIES IN THE SIPHONALIA SUTTERENSIS ZONE—

(Continued)

Barbatia morsei Gabb oo.....0.020. cece ccececeeeeeeeeeeeee eee

BaD AULA ASD etal ep ceet cc cect ce. ee eee mene ers Be NYS

Cardium marysvillensis Dickerson...._................... M4 x x
(QLopeopvuiey jaye Went bese (ks) 0} oy eee eee x ae K
(OfopelahwUkey PaYoy esol KC Ei) 0) on eee eee nee ieee iee eee <
(@raSSaAtellitesi SD ig eee cere at eee eres ences

Crassatellites grandis (Gabb) —...00.....0222222.2200-------- x on X
Diplodonta polita (Gabb) —..0000000002 eee

Dosiniayelevata (Gabbe 2.2.2 -c2..ccscc_2sscceces cav-ceeseoeeeee eee 7 x

GyiclMeEris (COM GaP: cece cocee cawcccnacscecacsceenceneeceeanseccoase-s

Glycimeris marysvillensis Dickerson...................

Isocardium tejonensis Waring .................-.-

JG(Cley, Fegan! (Olopmbes Kell Aeees aa ee eee

Macrocallista conradiana (Gabb) ~.....---............

MCT GET C PERS D i cccceccees 2-cotescccececcceccveeeucx<tesesescces-cnesewens

Meretrix ovalis Gabb 200002200 <—

Meretrix hornii Gabb ~..00...00002002002220 eee ”

Modiolus ornatus (Gabb) ....
Nucula cooperi Dickerson .........0..000.000......---2--0-------
Ostrea aviculaformis Anderson ....-.....0.-..2000220.-..
Ostrea cf. appressa GabbD .........2..2---20eeeeeeeeeeeeeeee ees
Placunanomia inornata Gabb —...0....00...00000.02000..---
Phacoides cretacea (Gabb) —...000200002 eee

JEXSY Gy HSV OLS) 0 Sire 2e eee aoc RSS ec ER en Be es x

Psammobia hornii (Gabb) —....00222200 22 ’ = x
Spopishbley saaveserertenaahl JEPVe eh Col ee ere eee

Solen parallelus Gabb
Tellina sutterensis Dickerson
Tellinga longa Gabb 20.00.22... ceteee ec eeeeeeeeeeeeeeeeeeeeeeeee

HOT COO SD eerscccceee oe eee hc heans ee venetian eae 2 ae
Venericardia planicosta merriami Dickerson.... x x
WiGTICTU CAT OUAs: SDrg ssseesencee eee sees — “pn x
Cadulus pusillus (Gabb) .00...0022...22.oeeeeceeeeeceeeee eee

Dentalium stramineum Gabb —..W0002.00002.2200202....-

Ancilla (Oliverato) californica Cooper................

PASS UV ATE Se sae cee cess weer es ee ee
Architectonica weaveri Dickerson ......0.2002000.....

Architectonica ullreyana, n. Sp. 200202222 eee eee x

‘Alcmaea sruckmanis, Me SPs cee see-ccsece-c-coee ess ecee-saees eee

Bittium featherensis, n. sp. 002220. c ieee eee

Bittium longissimum Cooper ............0022.0000000.......-. : a Sue
Bullaria Worm (Ga DW) cc ccceese cesses cee bees ae x
Cancellaria irelaniana Cooper ..--.....02200022200.2..2--00---

Cancellaria stantoni Dickerson —...W..0000000000000.0.0.-.-. g

Calyptraea excentrica (Gabb) 000.2... x

Caricella stormsiana Dickerson
Calliostoma arnoldi Dickerson ~.........00000000.0000.....-
Cerithiopsis orovillensis, n. sp. -...-...--...00---.---------
Chrysodomus martini Dickerson .................... x

408 University of California Publications in Geology (Vou. 9

List or SPEcIES From LOCALITIES IN THE SIPHONALIA SUTTERENSIS ZONE—

(Continued)

1853 1856 692 2225 2365
Clavella tabulata Dickerson x ee aie nie aa
Cordiera gracillima Cooper .... x x 3 x Sees
(Opralilanaieh (tofsureyieh (Creo) 0) eee ree x zae x
Drillaay wllrey.ania (COO Cry parse aes eee x x
Drie sGOOPETIG Ws sS We eeca cress sect -cece ee ee eececeeeeereeeoeeeeees x - a E
DrilliasorovallemSiS ss mes paeeesscesas erence eens cree ae eae ane a x
Exilia perkinsiana (Cooper) x x
Exilia dickersoni (Weaver) x
Fusinus lineatus Dickerson ..._..00.02222.22222..222...------ x
LD DISbabis; seoleh eee egWl, tol, yo), pee x : : ? ae
Ficopsis remondii Gabb —..-..0.0-222.222.2--2-----2----2--+-- x = pee re ee
Galeodea tuberculata (Gabb) .......22222220202....-------- x rae sete esa as
Lunatia nuciformis Gabb .................000.222.22-..----00---+ x x x
WU ayeKexeKopoueeyey yen iusik, aol, Cjol, -ee ee x 2 ° x :
Murex (Ocinebra) nashi, n. sp. ... x
IN GCA SGD yes ccc rrre are oe cae t eae ay acer a a ea Ser ne anna eon ee aes _— ee x
Nyctilochus diegoensis (Gabb) -..........00202002020022.... nee fee anh x i.
Nyctilochus thitmamiy ne (Sp) cccece eee eeeseuse ee ees ae — ane x Pes
Nyctilochus californicus Gabb x x Boke ie ee
INy.ctilocliusy wiliitimeyas Galo i seeeeeece soeeeeeeeeereee we x x ae,
INGSO} Ont ay Gia) 2oe aoe cesses eee one eect ea seeaeess x ra
ING Vera sS1 OOS an Gab ee case ee ae cree ee x x —
INN Lea ey tXete titel (CEN 0 0) a ere eel rere eer x x
Olivula marysvillensis Dickerson ..........00000......... x
Olivella mathewsonii Gabb ........0002..222---.0----0-0------ x x
Périssolax iblaker sGConradh) se x
Surcula crenatospira Cooper ...........002..2....22222-------- x
Surcula holwayi Dickerson .... x
Sureula clarki Dickerson .0..0.02.000.20002000c0e2--- ante x x
Surcula davisiana (Cooper) ..........00.0002222222.2222-20-- x
Surcula (Surculites) sinuata Gabb.........0000......... x ues pa
Siphonalia sutterensis Dickerson —........0000.00002...... x = x i
Terebra wattsiana Cooper .... x a
PUT TUS A ay GSP seesaw ee eee eee Meee ae = x
Turritella merriami Dickerson......... eee x x x x
Turris andersoni Dickerson ....-0....20.....0.00022.0202----- x
MunriSs1MCOnStamss COOP Cie tee scseeses anes nee ee x x a
Turris monolifera Cooper..........0022.....2..ccceeeeeeeee eee x x x
Murris Suburalis (COOPER) 2 se crc eeeeeeee eee eee x x
Volutay lawsona) Dickerson ce: se ee ener x x 3
COPEW al CLS) GES) OS spy eee es en Pe x fie es;
DVATVECHIOGIUIS SDs ee tetereee eee et e oee x =

List oF LOCALITIES

1853. Marysville Quadrangle. Tejon Group. About two and one-half
miles west, ten degrees north of South Butte in small cafon east of
county road. Coll., R. E. Dickerson.

1856. Marysville Quadrangle. Tejon Group. Two miles east of South
Butte. Coll., R. E. Dickerson.

1916] Dickerson: Tejon Eocene of California 409

692. Marysville Quadrangle. Tejon Group. Two and one-eighth miles
east, ten degrees south of South Butte. Coll., C. K. Studley.

2225. Chico Quadrangle. Tejon Group. Two miles north of Oroville
in the Dyer mining shaft. Colls., J. Ruckman and R. E. Dickerson.

2365. Jackson Quadrangle. Tejon Group. Red sandstone quarry three
miles southeast of Buena Vista. Coll., R. E. Dickerson.

2067. Sonora Quadrangle. Tejon Group. One mile south of Merced
Falls on top of a low hill, “Planicosta Butte’. Coll, R. E. Dickerson.

Of the species listed the following have not been reported at lower
horizons in California:

Trochocyathus(?) perrini, Barbatia, sp. a., Cardium marysvil-
lensis(?), Glycimeris marysvillensis, Venericardia planicosta mer-
riami, Architectonica weaveri, Bittium longissimum, Caricella storm-
siana, Cordiera gracillima, Calliostoma(?) arnoldi, Galeodea
sutterensis, n. sp., Fusinus lineatus, Olivula marysvillensis, Chryso-
domus martin, Surcula crenatospira, Surcula holwayi, Surcula
davisiana, Siphonalia sutterensis, Terebra wattsiana, Voluta lawson,
Bittium featherensis, n. sp., Cerithiopsis orovillensis, n. sp., Drillia
coopert, Drillia orovillensis, Nyctilochus thunant, n. sp., Murex nashi,
Hesp:

A study of a littoral facies of the Siphonalia sutterensis fauna at
Oroville, at locality 692, and at the mouth of Little River, North
Fork of the Umpqua River in beds near the top of the Tejon group
(Umpqua Formation), confirms and reinforces the writer’s previous
conclusion that ‘‘The unique character of the Marysville Buttes
fauna appears to be due to its representing a period from which no
adequate fauna had previously been obtained... . That it evolved
from the typical Tejon there can be little doubt. . . . In other words,
the evidence indicates that the Marysville Buttes fauna represents
a later zone or stage of the Eocene than the typical Tejon.’’ The
faunal list given above demonstrates conclusively that the Siphonalia
sutterensis fauna was evolved from the typical Tejon and that the
fauna is in reality much closer to the Tejon than the writer sus-
pected three years ago. On this account the fauna is placed as the
uppermost zone of the Tejon group in California.

CORRELATION OF THE IONE AND THE AURIFEROUS GRAVELS
Various workers in Sierran geology, including Whitney, Tur-
ner, Diller, and Lindgren, have recognized a genetic relationship
between the auriferous gravels and the lone formation. Diller?’ says

57 Diller, J. S., Topographic Revolution on the Pacific Coast, Fourteenth
Annual Report, U. S. Geological Survey, Part If, p. 420, 1894.

410 University of California Publications in Geology (Vor. 9

that ‘‘On stratigraphic grounds the auriferous gravels are regarded
as contemporaneous with the Ione formation of the Sacramento Valley,
but here too as in the earler auriferous gravels, the fossil plants and
shells appear to indicate that they belong to the Miocene.’’

Lindgren®* in his description of the Ione formation summarized
conditions succinctly as follows:

During the Miocene period and contemporaneously with the accumula-
tion of the later pre-voleanic gravels on the slopes of the Sierra Nevada,
there was deposited in the gulf then occupying the Great Valley a sedi-
mentary series of clays and sands to which the name Ione formation has
been given. The water in this gulf was probably brackish; no marine fossils
have been found in the Ione formation along the foot of the range, but
fossil leaves, vegetable material, and in places, coal are abundant. At the
mouth of the rivers which descended from the Tertiary Sierra Nevada
extensive delta deposits were accumulated, and it is thus difficult in many
places to draw any exact line between the Ione formation and the river
gravels proper. The gravels in the formation are locally auriferous, though
generally poor, because spread over large areas.

The lowest and oldest Tertiary auriferous gravels lie in troughs over
which the Ione formation has transgressed, in places a depth of more than
500 feet. At many localities the sandstones and clays of the formation
merge directly into the upper river gravels of the so-called benches. On
the other hand, the thick gravels of the rhyolitic are distinctly later than
the Ione formation. Turner has shown that in the Jackson Quadrangle
extensive short or delta gravels of interrhyolitic [these gravels are not
interrhyolitic but are andesitic, R. E. D.] age rest on the eroded surface of
the Ione (see Pl. 11, B, p. 72).* The Ione formation belongs to the Tertiary

The greatest thickness of the formation measured is in Calaveras County
in the Jackson Quadrangle, where Turner has determined it to be about 1000
feet. Post-Ione erosion has removed the formation entirely over large areas.

The most northerly exposures of the Ione north of the Sierra Nevada,
have been observed by Diller on Little Cow Creek and Pit River in the
northwest corner of the Lassen Peak Quadrangle, Shasta County. The clays
and sands are here directly overlain by andesitic tuffs and rest on meta-
morphosed slates of Jurassic or Triassic age at an elevation of about 2000
feet. South of this locality few exposures are seen until the Oroville Table
Mountain is reached, a distance of nearly 100 miles. At this place, a capping
of basalt, somewhat earlier than the andesitic flows, has preserved the Ione
intact. The formation here consists of fine gravels, white clays and sands,
and reaches to elevations of about 1200 feet. (See Pl. IV, B; fig. 4, p. 86;
and fig. 5, p. 90.)* With insignificant exceptions, no further exposures occur
between this point and Lincoln in Placer County, where some white ¢Glays
are preserved underneath a capping of andesitic tuff in the midst of Quater-
nary gravels and a few miles west of the first outcrops of the pre-Cretaceous
rocks, usually referred to by the collective name ‘Bedrock series”.

About 40 miles northwest of Lincoln, in the late Tertiary andesitic

58 Lindgren, W., Tertiary Gravels of the Sierra Nevada of California,
Professional Paper, No. 73, U. S. Geological Survey, pp. 24 and 25, 1911.
*Lindgren’s Plates.

1916] Dickerson: Tejon Eocene of California 411

volcano of Marysville Buttes, clays, sands and gravels of Miocene age have
been brought up by the intrusion of igneous bodies and, although they are
so much disturbed that the stratigraphic sequence can not be made out,
there is strong probability that these strata should be identified with the
Ione. They contain marine fossils associated with impressions of deciduous
leaves, and the gravels contain some gold.

South of Lincoln the Ione formation is better exposed because it has
been protected by andesitic tuff, but it does not reach a higher elevation
than about 200 feet. South of American River the outcrops are more exten-
sive, and the formation attains its greatest development in the foothills of
Calaveras County. The lower part, consisting of white clay and sand, reaches
a thickness of 860 feet or more and contains beds of lignite of poor quality.
Above this rests a white sandstone which attains a thickness of 100 feet or
more. A clay bed also of light color, 100 feet thick, overlies this sand-
stone. Near Valley Springs the Ione attains elevations of 1000 feet, and
its highest members are probably several hundred feet above the deepest
gravels of the Tertiary Calaveras River, which here debouches into the plains
but which is not visible in this vicinity.

From all this it appears that during the later part of the prevolcanic
gravel period the Ione formation transgressed along the whole front of the
Sierra to a present elevation of somewhat more than 1000 feet. So far as
can be judged from the present exposures, there has been little differential
elevation along the front of the range since the time of the deposition of
the formation. In other words, the fluctuations of the shore line are now
indicated by horizontal lines at least between the Oroville Table Mountain
and the foothills of Calaveras County.

The extent of the erosion which followed immediately after the deposition
of the Ione formation along the foothills was greater than would be sup-
posed from a study of the deposits in the rivers higher up in the range.
The sequence is particularly well shown around the Oroville Table Mountain
and in the foothills of Calaveras County. At the former place the andesitic
tuffs (Tuscan tuff of Diller), which in Placer County appear to overlie the
Ione formation conformably, are at least 500 feet below its top members.
At the mouth of the old Yuba River there is a conspicuous absence of
the Ione formation and the andesitic tuffs rest immediately on the bedrock,
at elevations as low as 200 feet, and in the old river channel lie immediately
above the heavy gravels which are presumably of Eocene age. At this
locality no extensive mud flows of rhyolitic character appear to have reached
the valley, although they are abundantly present in the longitudinal basin
which begins at North Columbia, Nevada County, 15 miles east. At the
mouth of the Tertiary Calaveras River, on the other hand, shore gravels
or delta gravels spread out up to a present level of 500 feet, and these
gravels rest on the gently eroded surface of the Ione formation.

These interrhyolitic gravels were again subjected to some erosion; imme-
diately after this followed the prolonged epoch of andesitic flows. The tuffs
which were spread over a large part of the Sierra Nevada were worked
over by the rivers and spread as thick masses of voleanic gravels and sands
over the eroded surface of the Ione formation and the interrhyolitic gravels.

The ‘‘gravels of interrhyolitic age’’ resting upon ‘‘the eroded sur-
face of Ione’’, described by Lindgren are in reality of andesitic or

412 University of California Publications in Geology [Vou. 9

imterandesitic age. In the locality figured in Pl. 11 B, p. 72, of his
“Tertiary Gravels of the Sierra Nevada,’’ the gravels contain abund-
ant boulders of andesite as well as rhyolitic fragments. Turner®®
describes this locality as follows: ‘‘This conglomerate consists of a
variety of pebbles—quartzite, mica schist, quartz-porphyrite, grani-
toid rocks, andesite, and rhyolite being represented.’’

From Lindgren’s excellent statement and the conditions described
above at Oroville Table Mountain it is evident that a correlation
between the Tertiary gravels and the Ione is made possible. Lind-
geren recognizes the following divisions in the Tertiary gravels and
the voleanic formations associated with them: a, Deep gravels of
Eocene age; b, bench gravels; c, rhyolitic tuffs and interrhyolitic
channel; andesitic tuffs and intervoleanic channel. The accompany-
ing figure copied from Lindgren’s paper shows the relations of these
deposits graphically (see figure 7). A fourfold division of the

79 Ean cA et AV Lh Oe ay dee Nurse Wests hy aD AZ. FAV da a mT
ae Fog iaae eg eee se Perea E77
Tau Rhealep sos on BV~9 Jr B25 25 v \
se SEO Ly
ourt SAN QE
WS

Fig. 7. Schematic representation of the four principal epochs of Tertiary
gravels in the Sierra Navada. a, Deep gravels (Hocene); b, bench gravels
(Eocene); c, rhyolitic tuffs and interrhyolitic channel; d, andesitic tuffs and
intervoleanic channel. (Adapted from Lindgren.)

Ione is better for the purpose of correlation than Turner’s threefold
division. The lowermost division in the type locality of the Ione is
(1) the sand and gravel member in the bottom of the deep basin near
Ione, 500 to 600 feet; (2) clays derived from rhyolite with inter-
bedded lignite, 100 to 200 feet; (3) white and red coarse-grained
sandstone with scales of alunite, 25 to 75 feet; (4) rhyolite and its
clay derivatives (‘‘clay rock’’ of Turner), 0 to 50 feet. Andesitic
tuffs or their equivalents, the Neocene shore gravels, are sometimes
found resting upon the third or the fourth member of the Ione. The
probable relationship between the lowermost member of this sequence
and the deep gravels was indicated by Lindgren: ‘‘Near Valley
Springs the Ione attains elevations of 1000 feet, and its highest mem-
bers are probably several hundred feet above the deepest gravels of

59 Turner, H. W., Rocks of the Sierra Nevada, Fourteenth Annual Report,
U. S. Geological Survey, p. 468, 1894.

1916] Dickerson: Tejon Eocene of California 413

the Tertiary Calaveras River, which here debouches into the plains
but which is not visible in this vicinity’’. Evidently the deep gravels
should be correlated with the basal sands and gravels of the Ione;
the rhyolite and interrhyolitic channel has an equivalent in the last
three members of the Ione; the andesite of the Sierras is coextensive
with the andesitic tuffs and Neocene shore gravels of the valley border.

The third member of the Ione, the red sandstone, contains casts
of Venericardia planicosta merriami and other Eocene shells which
are characteristic of the Siphonalia sutterensis zone of the Tejon
group; hence the lower portion of the rhyolitic beds and the inter-
rhyolitic channel, the correlatives of second and third members of
the Ione formation, are Eocene in age. No fossils have yet been found
in the fourth member of the Ione, the ‘‘clay rock’’ of Turner. This
correlative of the uppermost portion of the rhyolite of the Sierra
Nevada is apparently conformable with the third, the red sandstone
member. On the basis of stratigraphy, the fourth member is prob-
ably Eocene in age, in part at least. If there is any genetic connec-
tion between the white shale of the Coalinga District and the rhyolite
of the Sierra Nevada, then an Oligocene age is suggested for the
uppermost part and Eocene age for the lower portion. However, as
interesting as this possibility may be, it is a difficult one to verify
and its consideration is merely a suggestion for future investigation.

Wide-spread unconformity between the andesite and the rhyolite
is shown in many places in the Sierra Nevada, and the same relations
exist between their correlatives of the valley border, the Neocene
shore gravels and the uppermost rhyolitic member of the Ione. In
places the andesite is coextensive with the andesitic tuffs which over-
lie the rhyolite of the uppermost Ione; hence the stratigraphic rela-
tions between the andesite of the mountains and the andesitic tuffs
of the valley border are entirely clear. The andesitic tuffs have
yielded several floras, but no fauna which is properly authenticated
has been reported from them.

The floras listed by Knowlton® from Corral Hollow and south of
Mount Diablo are both from the San Pablo, an upper Miocene for-
mation as determined by Clark.®' The age determination of the
andesitic tuffs will probably be made when larger floras from the

60 Knowlton, F. H., Flora of the Auriferous Gravels of California in
Tertiary Gravels of the Sierra Nevada of California, Professional Paper No.
73, U. S. Geological Survey, pp. 57 to 64, 1911.

61 Clark, Bruce L., The Fauna of the San Pablo Group, Univ. Calif. Publ.
Bull. Dept. Geol., vol. 8, pp. 442-448, 1915.

414 University of California Publications in Geology [Vor. 9

marine Miocene formations of the Coast Ranges are carefully com-
pared with those of the Sierran andesitic tuffs.

The determination of the age of the rhyolitic and interrhyolitic
channels as Kocene differs from previous age determinations. The
previous evidences of age were vertebrate remains and floras from the
bench gravels and rhyolitic tuffs. Unfortunately the vertebrate local-
ities are uncertain. Lindgren says:

The number of species of clearly prevoleanic occurrence is not large.
The most important localities are Douglas Flat and Chili Gulch, in Cala-
veras County, and the Tuolumne Table Mountain not far to the south,
in Tuolumne County. In the Calaveras County localities bones and teeth
of a species of rhinoceros, described by Leidy under the name of R. hes-
perius, have been discovered. At Douglas Flat was also found a tooth of
the pachyderm Llotherium, which belongs to the Eocene or Oligocene
(White River Group of the Rocky Mountain region) . . . These few
occurrences complete the list of fossils which Whitney considered authentic
and beyond doubt derived from the Tertiary gravels.

The forms might represent either Oligocene or Eocene species.

Knowlton®? who has studied all of the floras of the West Coast
described the life conditions of the flora of the auriferous gravels
in a note to Diller as follows:

Lesquereux, as you have already stated, argued that the presence of
a large number of lauraceous plants indicated a region analogous in at-
mospheric conditions to Florida. From my own studies which embrace
a much larger amount of material than Lesquereux had, I am not only
prepared to accept this statement, but to show that it now has stronger
support than he could have given it. Lesquereux knew only about 50
species of plants in the auriferous gravels, whereas the present known
flora embraces nearer twice that number. Of this number the following
genera are distinctly tropical or subtropical in their distribution: Laurus
(4 species), Persea (3 species), Cinnamomum (2 species), and Oreodaphne
(2 species), all belonging to the Lauraceae. In addition to these there
is Artocarpus and Zizyphus, each with 2 species, Ficus with 6 species,
and Sabalites with 1 species, or 22 species in all, representing at least
20 of the entire present flora. The present flora of Florida has only 5
genera and 8 species belonging to the Lauraceae, which represent less
than one per cent of the whole flora, while, as stated above, there are 4
genera and 10 species in the auriferous gravels, representing fully ten
per cent of that flora.

Following is a list of genera, with the number of species in each
having living representatives confined in the main to temperate regions,
some of them growing at elevations at or but little above sea level: Aralia
(4), Platanus (2), Cornus (4), Juglans (5), Liquidambar (1), Magnolia
(4), Quercus (15), Viburnum (8), Rhus (6), Alnus (8). Of course it is
quite impossible to say that these species actually grew at the above alti-

62 Knowlton, F. H., in Topographic Revolution on the Pacific Coast, Four-
teenth Annual Report, U. S. Geological Survey, Part II, p. 421, 1894.

1916] Dickerson: Tejon Eocene of California 415

tude, but simply that from what we know of the living species, some or
perhaps all of them may have done so. That is, there are none of these
genera confined to high elevations. On the other hand there are a number
of genera as Alnus, Betula, Populus, Salix, ete., that we would hardly ex-
pect to find in great abundance at a very low altitude, but like the last
mentioned genera, they are not exclusively confined to high altitudes. They
might well have grown on land in close proximity to a body of water
connected with the sea, such as the area under discussion appears to have
been during their deposition. There are also several genera of conifers,
as Pinus, Araucarioxrylon, Cupressinoxylon, Pityorylon, which alone would
appear to argue a greater elevation than appears to have prevailed. If
these genera were in great abundance, it would still further strengthen
that view, but on the contrary they are very rare, the genus Pinus being
represented by a single somewhat doubtful example. From their lightness
and well-known power of long resisting the processes of decay, they might
well have been transported from long distances, for with the exception of
the pine-needles there is no evidence to show that any of them grew where
they were fossilized.

From these facts Diller®* concluded ‘‘that during the Miocene
the country was a series of plains and peneplains with low mountain
ranges; or in other words, the country was but little above its base
level of erosion”’

Lindgren’s®* very careful work on the Tertiary topography of
the Sierra Nevada alters this conception considerably and_ places
before us an indisputable body of facts.

The evidence available shows conclusively that at the time when the
oldest gravels, probably of Hocene age, began to accumulate the Sierra
Nevada was a mountain range as distinct if not as high, as at present. The
rivers headed near the points where the corresponding modern rivers
begin now, in a region of lofty peaks and ridges. In geologic literature
it has been repeatedly stated that the Tertiary surface of the Sierra Nevada
is that of a peneplain, a conclusion absolutely at variance with the opinions
of those who have actively studied the range. :

The Tertiary topography of the western slope consieted of four units.
Along the valley line extended a number of greenstone ridges attaining
elevations of 1,500 to 4,000 feet. They are shown perfectly plainly in
Yuba and Butte counties, for instance, by Brown’s Valley Ridge and the
Oregon Hills, through which the Yuba river of Tertiary time broke through
in a deep canyon. In Placer County an area of softer granodiorite reached
the valley and in this vicinity—for instance, near Rocklin—the idea of a
peneplain is more nearly realized than elsewhere. In Calaveras County,
the Tertiary Calaveras River broke through this barrier in a deep valley
similar to that of the lower Yuba but much more abrupt; near San An-
dreas, for instance, these greenstone ridges rose 2,000 feet above the river
in a deep canyon. In Placer County an area of softer granodiorite reached
prominently emphasized in the Pefion Blanco Ridge and Bullion Mountains.

63 [dem, p. 422
64 Lindgren, Waldemar, The Tertiary Gravels of the Sierra Nevada of
California, Professional Paper 73, U. 8. Geol. Surv., p. 37.

416 University of California Publications in Geology [Vou. 9

A study of Knowlton’s list as given in Lindgren’s ‘‘ Tertiary Gravels
of the Sierra Nevada’’ shows that most of the forms mentioned by
him above as showing a subtropical climate were found in the bench
gravels or the rhyolitic tuffs.

The mixture of plants of the lowlands and plants of the high-
lands to which Knowlton refers is explained in part by the facts
that his fauna is a mixture of forms obtained from the andesites and
from the bench gravels and rhyolite, and in part by Lindgren’s clear
picture of a mountainous region of fairly great relief bordering a
coastline. The fact that many of the species are subtropical is not
contrary to the conclusions concerning Eocene climate which the
writer derived from the study of the marine invertebrates of the
Tejon Eocene. In fact a subtropical climate is inferred from both
studies and hence there is nothing in the floras which would reject
an Kocene age determination for the bench gravels and the rhyolite.

In addition to this, some direct evidence concerning Eocene floras
was obtained by Diller. Several of the species listed by Knowlton®
have also been reported from a known Tejon locality in Oregon.
Among these were Magnolia lanceolata and Aralia whitney. Con-
cerning this flora Knowlton remarks that ‘‘they have both been
reported from the Fort Union formation as well as from the Jone
formation of Shasta County, California, and other localities ...a
fact which undoubtedly robs them of the significance they might
otherwise have as tending to prove the Eocene age of all the aurifer-
ous gravels’’. Knowlton assumed a proven Miocene age for the Ione.
This assumption may be due to the determination of some poorly
preserved marine fossils from the supposed Ione of the Marysville
Buttes as Miocene. Better material obtained, from this locality
demonstrates the Eocene age of these beds. It has been shown
above that the age of the Ione is Eocene and hence this evidence
supports an Eocene age for the auriferous gravels most decidedly.
Thus far there is no evidence which can not be legitimately inter-
preted as indicating an Hocene age for the deep gravels and most
of the rhyolite of the superjacent series of the Sierra Nevada.

SUMMARY OF GEOLOGICAL EVENTS ALONG THE WESTERN
FOOTHILLS OF THE SIERRA NEVADA

The historical geology of the east side of the Great Valley border
from Chico time to the Recent is in summary:

65 Knowlton, F. H., in Professional Paper No. 73, p. 64, 1911.

1916] Dickerson: Tejon Eocene of California 417

(1) Pre-Chico erosion.

(2) Chico transgression. Shore line moves eastward to present ele-
vations of 800 feet.

(3) Post-Chico erosion. Shore line moves west of the eastern valley
border.

(4) Ione (Eocene) transgression. Shore line moves eastward at least
to present elevations of 1000 to 1200 feet.

(5) Post-Ione erosion. Shore line moves permanently west of valley
border.

(6) Deposition of interandesitic shore gravels.

) Pliocene and Pleistocene erosion—Sierran period.

(a) Deposition of ‘‘Pleistocene shore gravels’? up to eleva-
tion of 450 feet.

(b) Deepening of stream beds along valley border by 100 to
300 feet.

(c) Deposition of lower bench gravels.

(d) Deposition of present alluvium.

Such in brief outline is the series of events as interpreted in accord-
ance with the results given above. This sequence does not apply to
the southern end of the valley border, as a different series of events
seems to have taken place in that region.

SUMMARY

(1) The sedimentary strata beneath the Older Basalt of Oroville
Table Mountain and Oroville South Table Mountain represents the
uppermost Tejon of California, the Siphonalia sutterensis zone.

(2) The beds beneath the Older Basalt are strand-line deposits.

(3) The auriferous gravels as represented by the channels ex-
posed at the Cherokee Mine and in Morris Ravine are stream-laid
deposits, the correlatives of the marine sediments exposed at Oroville
South Table Mountain and hence their age is Tejon EKocene.

(4) The correlative of the so-called Ione formation is represented
in the Marysville Buttes region by deep-water sediments of Tejon
age. These strata have yielded an abundant fauna which has a close
relationship to the littoral fauna of Oroville and other Ione localities.

(5) The Ione formation is of Eocene age and is merely a facies
of the Tejon group. If the name is retained, it should be interpreted
as the uppermost or Siphonalia sutterensis zone of the Tejon group.

(6) The Ione has been repeatedly correlated with the auriferous

418 University of California Publications in Geology [Vou. 9

gravels of the Sierras and the upper portion with the rhyolitic tufts.
It can no longer be doubted that the Ione is of the same age as the
rhyoltiec tuff and the bench and deep gravels, and since the Ione is
clearly Tejon-EKocene, the correlatives must be upper Eocene, at least
in part, and the land equivalent of the marine Tejon.

TEJON GROUP IN THE VICINITY OF Fort TEJON
STRATIGRAPHY

The Tejon group at the type locality is a portion of an east-west
strip which extends from Tunis Creek on the north flanks of the
Tehachapi Mountains to a point about three miles southeast of Patti-
way where it is cut off by the San Andreas Fault. The map (see
figure 8) which is adapted from the ‘‘Preliminary Report on the
Geology and Possible Oil Resources of the South End of the San
Joaquin Valley, Cal.,’’ by Robert Anderson shows the general distri-
bution of the Tejon very satisfactorily.

The Tejon strata in the vicinity of Grapevine Creek rest upon a
Basement Complex consisting of granite rocks and associated schists.
The beds in general have a steep north dip of 75° to 85° but are dis-
turbed in places so that the dip is reversed. The basal member
about 250 to 300 feet in thickness consists of a very coarse conglomer-
ate derived from the granitic rocks of the Basement Complex. This
member is overlain by about 1000 to 1200 feet of thin-bedded brown
sandstone with subordinate strata of dark gray, clay shale containing
limestone nodules. The sandstone is, in places, conglomeritic and in
one locality the dark gray pebbles of shale yielded a small pecten.
The occurrence of this pecten suggests the deposition of Cretaceous
deposits which were completely removed during upper Eocene time.
The uppermost strata, about 1200 feet in thickness, consist chiefly of
light tan sandstone with subordinate strata of shale and brown sand-
stone. The total thickness of the Tejon group along Grapvine Creek
(Cafiada de las Uvas) is about 2500 feet. The Tejon is overlain by
voleanic ash of Oligocene or Miocene age on the west side of Grapevine
Creek. Martin states that the uppermost Tejon beds in Live Oak

Creek are covered by a lava flow.
FAUNA
The middle portion of the Tejon group in the vicinity of Grape-
vine Creek is particularly rich in upper Eocene species. The basal
beds yielded but a small fauna (Cal. Acad. Sci. locality 246) which

TN \N. Butto

Dickerson: Tejon Eocene of California

1916]

Ses
(SUNSET BRANCH)

< Si SS SS
SSS |

Se
MT

De Gas

NV biog MIGD'D a
dio Mtn

eo,
S52%5

Map showing type locality of Tejon group.

Pesce /

RAO

LLY,

x aw

Y
Ux)
4

OH

I7W /“_ARI6W

NAR 20W 1 ;
REE <
SNK .
| Tejo
TSA

RXR

RD, /
P77

tifa 7,

“on
Re
ee.
ALL
ntimony Peak ON
UG Si

a
LA

Gy

(After R. Anderson.)

Seale 1:500,000.

LEGEND

Quaternary
Ceposits

Later Tertiary
formations

Tejop formation
(Eocene)

Y

ZA,

Crystalline
rocks

Chiefly granite

(pre-Cretaceous/

ae

420 University of California Publications in Geology [Vou. 9

consists of Spondylus carlosensis, Barbatia, sp., Meretrixz, sp. and
Ostrea, sp.

Beds about 300 feet above the base (Univ. of Cal. locality 458)
ylelded an excellent fauna. This fauna, however, does not differ
essentially from that of the beds higher in the section. The faunas
from several other localities which are listed below do not differ mate-
rially from one another but all appear to represent one phase. This
faunal unity is in consonance with the sedimentary record as Ander-
son®® described it: ‘‘The beds throughout possess a marked similarity
and give every appearance of representing a period of continuous
deposition in one basin. They are therefore to be regarded as making
up a formation, and not a larger division of the geologic column.”’
The writer is in complete agreement with Anderson’s views as ex-
pressed here in relation to the type Tejon. However, beds both higher
and lower than the Eocene of Canada de las Uvas occur in other parts
of the state, notably in the vicinity of Mount Diablo, along Cantua
Creek, Coalinga Quadrangle and at the Marysville Buttes. Owing to
these facts the expression ‘‘Tejon group’’ is fully warranted upon
both stratigraphic and faunal grounds.

The fauna of the type Tejon corresponds to the Rimella simplex
zone of the Mount Diablo region.

List oF Species From Type Locauiry or TEJON

Turbinolia, sp. Dosinia elevata Gabb
Dendrophyllia tejonensis Glycimeris sagittatus (Gabb)
Nomland Glycimeris fresnoensis, n. sp.
Schizaster lecontei Merriam Glycimeris eocenicus (Weaver)
Acila gabbiana, n. sp. Glycimeris ruckmani, n. sp.
Arca hornii Gabb Leda gabbi Conrad
Avicula pellucida Gabb Leda uvasana Dickerson
Barbatia morsei Gabb Lucina cumulata Gabb
Crassatellites uvasana Gabb Lucina, cf. cretacea
Crassatellites grandis Gabb Lucina (Myrtaea) taffana, n. sp.
Crassatellites mathewsonii Lucina gyrata (Gabb)
(Gabb) Lucina nasuta Gabb
Cardium brewerii Gabb Macrocallista andersoni Dickerson
Cardium cooperii Gabb Macrocallista conradiana (Gabb)
Cardium, cf. olequahensis Weaver Marcia quadrata (Gabb)
Corbula hornii Gabb Meretrix hornii Gabb
Corbula parilis Gabb Meretrix ovalis Gabb
Corbula harrisi, n. sp. Meretrix tejonensis Dickerson
Corbula uvasana, n. sp. Meretrix uvasana Conrad

66 Anderson, Robert. Preliminary Report on the Geology and Possible
Oil Resources of the South End of the San Joaquin Valley, Cal., Bull.
471, U. S. Geol. Surv., p. 118, 1912.

1916]

LIstT OF

Meretrix, cf. olequahensis
Weaver

Modiolus ornatus (Gabb)
Macoma, sp.
Nucula cooperi Dickerson
Ostrea, sp.
Psammobia hornii (Gabb)
Psammobia, sp.
Pinna barrowsi Dickerson
Spisula merriami Packard
Solen parallelus Gabb
Septifer dichotomus Gabb
Spondylus carlosensis Anderson
Tellina remondii Gabb
Tellina howardi Dickerson
Tellina californica Gabb
Tellina joaquinensis Arnold
Teredo, sp.
Venericardia planicosta hornii

(Gabb)
Cadulus pusillus Gabb
Dentalium stramineum Gabb
Actaeon moodyi, n. sp.
Amauropsis alveata (Conrad)
Amauropsis andersoni Dickerson
Architectonica hornii Gabb
Architectonica cognata Gabb
Ancillaria elongata Gabb
Bullaria hornii (Gabb)
Cancellaria stantoni Dickerson
Calyptraea excentrica (Gabb)
Conus remondii Gabb
Conus weaveri, nN. sp.
Conus cowlitzensis Weaver
Conus hornii Gabb
Conus californiana (Conrad)
Crepidula pileum Gabb
Cylichna costata Gabb
Cypraea mathewsonii Gabb
Cypraea bayerquei Gabb
Cerithiopsis alternata Gabb
Chrysodomus ruckmani, n. sp.
Drillia raricostata Gabb
Drillia ullreyana Cooper
Exilia harrisi Dickerson
Exilia dickersoni (Weaver)
Epitonium tejonensis, n. sp.
Fasciolaria sinuata Gabb
Ficopsis remondii Gabb
Ficopsis hornii Gabb
Ficopsis cowlitzensis (Weaver )

Dickerson: Tejon Eocene of California

Species From Type LocaArity or

42]

TEJoN— (Continued)

Fusinus tumidus Gabb

Galeodea tuberculata (Gabb)

Hemifusus lewisiana Weaver

Lunatia hornii Gabb

Lunatia nuciformis Gabb

Murex sopenahensis Weaver

Mitra simplicissima Cooper

Mitra uvasana Dickerson

Naticina obliqua Gabb

Natica uvasana Gabb

Natica hannibali Dickerson

Neverita secta Gabb

Nyctilochus kewi Dickerson

Nyctilochus, sp. a.

Nyctilochus hornii (Gabb)

Nyctilochus washingtoniana (Weaver )

Nyctilochus sopenahensis (Weaver )

Nyctilochus cowlitzensis (Weaver )

Nyctilochus fusiformis (Gabb)

Nyctilochus californicus (Gabb)

Olivella mathewsonii Gabb

Odostomia, sp. a.

Odostomia packi Dickerson

Perissolax blakei (Conrad)

Potamides, sp.

Pseudoliva tejonensis Dickerson

Pseudoliva volutaeformis Gabb

Rimella simplex Gabb

Surcula io (Gabb)

Surcula (Surculites) sinuata Gabb

Surcula cowlitzensis Weaver

Surcula washingtoniana (Weaver)

Siphonalia bicarinata Dickerson

Spiroglyphus(?) tejonensis Arnold

Terebra californica Gabb

Turritella uvasana Conrad

Turritella uvasana bicarinata Dicker-
son

Turritella uvasana tricarinata Dicker-
son

Turritella buwaldana Dickerson

Turritella kewi Dickerson

Turris uvasana, n. sp.

Turris monolifera Cooper

Turris stocki, n. sp.

Turris, sp.

Voluta martini Dickerson

Voluta slevini Dickerson

Voluta, sp.

Whitneya ficus Gabb

422 University of California Publications in Geology (Vou. 9

TEJON GrRouP, Canrua District, CoALINGA QUADRANGLE

The great development of Eocene strata in the vicinity of Cantua
Creek in the northern portion of the Coalinga Quadrangle and their
complicated relationship to the underlying beds have interested several
investigators during the last ten years. The age of a portion of these
beds has been questioned by some investigators and a portion of these
Eocene strata has been assigned to the Martinez group. It is the
purpose of this discussion to show that the fauna of the lowermost
beds represent a lower zone of the Tejon group and that it is equivalent
to the Turbinolia zone of the Tejon group of Mount Diablo. A great
difficulty in the investigation of the Tejon group is found in the in-
complete description of its fauna. It has been the writer’s experi-
ence in collecting in the Tejon group that new forms will be found
at practically all places where the preservation is shghtly better
than usual.

HISTORICAL

F. M. Anderson*’ was the first writer to describe the beds in
the vicinity of Cantua Creek. He says:

The preceding list of fossils contains representative Hocene species
such as indicate that the beds are to be correlated rather with the Tejon
than with the Martinez division of the Eocene, and this accords with the
fact that the latter horizon has been considered local in its occurrence,
or extending only northward from the latitude of Mount Diablo, and also
with the fact that the Tejon Beds are found at New Idria and other points
only a few miles north of the limits of our own observations.

In a later paper®® he suggested a Martinez age for the lowermost
beds.

This area is also referred to by Arnold and Anderson.*?

J. A. Taff"? described the stratigraphy of this region and sug-
gested that the lowermost Eocene beds might be of Martinez age. He
deseribed an unconformity between these beds and the Domengine
sands.

Professor E. T. Dumble eave further notes upon the strati-

67 Anderson, F. M., A Stratigraphic Study in the Mount Diablo Range of
California, Proc. Cal. Acad. Sci. Third Series, vol. 2, pp. 162-168.

68 A Further Stratigraphic Study in the Mount Diablo Range of Cali-
fornia, Proc. Cal. Acad. Sci. Fourth Series, vol. 3, pp. 13-14, 1908.

69 Arnold, Ralph and Anderson, Robert, Geology and Oil Resources of
the Coalinga District, California, Bull. 398, U. S. Geol. Surv., pp. 62-71, 1910.

70 Taff, J. A., Proc. Palaeontological Society, 1912.

71 Dumble, E. T., Notes on Tertiary Deposits near Coalinga Oil Field
and their Stratigraphic Relations with the Upper Cretaceous, Jour. Geol.,
vol. 20, pp. 28-37, 1912.

1916] Dickerson: Tejon Eocene of California 423

graphy and referred a portion of the Eocene strata to the Martinez.

His description of the stratigraphic sequence is as follows:

To Messrs. Stanton, Merriam, Weaver and Dickerson is due the credit
of demonstrating in the Mount Diablo region the existence below the
Tejon of a series of beds of Eocene age, which is clearly distinguishable
from that terrane by its characteristic fauna and unconformable relation-
ship. This has been named the Martinez, but only meager accounts of
its stratigraphy are available and its existence was recognized at only a
few localities.

Our work now proves that this lower member of the Eocene is of
very considerable extent southward on the west side of San Joaquin
Valley; that it consists of three or more clearly defined members, and
that, in addition to the unconformity already described between it and
the Cretaceous, there also exists a decided unconformity between it and
the overlying Tejon.

The Martinez is well developed in Townships 17 and 18 South, Ranges
138 and 14 Hast, in the Salt Creek-Cantua region, and comprises a basal
bed of chocolate sands with glauconitic sands overlain by yellow sands
and conglomerates and these overlain in turn by other chocolate shales.
The generalized section of the Martinez in this particular area may be
stated as follows:

3. Upper chocolate shales comprising bluish shales at top, grad-

ing down into chocolate or brown shales which weather

to clays.

These rest upon other chocolate shales which become

sandier toward bottom. These shales vary in thickness.

600-900 ft.

2. Yellow sand and conglomerate.

Bluish sandy shales and thin sandstone, variable in thick-

ness. 200 ft.

Massive yellow sandstone with large dark brown segrega-

tions and concretions and some layers of bluish sandy shale.

Fine sand with local beds of conglomerate interbedded with

blue and brown shales; a considerable amount of glauconitic

material at base. 300 ft.
1. Lower chocolate shales.

Beds of chocolate and brown shale with small ferruginous

and limy concretions and layers of glauconitic sands. 1000 ft.

2,700 ft.

Dumble lists species collected “from the top of the lower chocolate
shales at a locality on Salt Creek in the SW % of NW ¥%, Section 25,
Twp. 18 S, R. 14 KE.”

The greatest surface exposure of these beds in this area is found in
Twp. 17 S., R. 13 E., where except for a band of Cretaceous along the
south line they form the surface rocks for the entire southern half of the
township. The exposure of the lower shale is only a half to three-
quarters of a mile in width and the upper shale occupies a similar belt,
but the yellow sandstone member has an average breadth of exposure
of nearly two miles. On the eastern line of this township this is narrowed

424 University of California Publications in Geology Vou. 9

to half a mile and the three members cross the north line of Twp. 18 S.,
R. 14 E., with a total width of less than two miles. This is again nar-
rowed toward the southeast until in Sec. 23 of this township the upper
brown shale and the greater part of the yellow sand has been removed
by pre-Tejon erosion, and, south of that point, so far as it occurs, the
Martinez is represented beneath the Tejon only by the basal shale with a
thin band of yellow sand overlying it through a part of the area.

Tejon Formation

The series of sediments here assigned to the Tejon admit of separation
into two distinct members; the lower of white sand and conglomerate
carrying a fauna in all respects identical with that of the original Tejon
locality, and an upper member of white shale which is not so fossiliferous
and which, as has been suggested by different investigators in this area,
may in part or as a whole represent the Oligocene.

The general section of the Salt Creek-Cantua region is as follows:

5. White shale. Feet.
White fissile organie shales, containing fish scales, teeth,
FOTAMINILETA» CLC eisai vuccaseneuoneteswra eveacn cane tele: choxeus ett cme seston 500

Lenses of fine brown sand.
White shale with local thin sandy strata................. 1000
Toca * friable: sands. crac: acsuere, sce susasvacetn oage.e asus det ee enous taed meee 0-30
Pink. to, “whiter Shale@viecce sis. sie.8 0 oisieyere os re.eherue ecke event tons 200
Bluish sandy shales grading up into pink shales........ 40
1,770

4. White sandstone and conglomerate.

Yellowish to white, usually fine sand................. 100-160

White massive sandstone and conglomerate with whitish

shale “inclusions: at’ the DaSCi ccc cree costs a evens vee cucnemeretens 20-40
200

In this portion of the field the base of the Tejon is a fossiliferous
conglomerate and sandstone which shows distinct unconformity with the
underlying Martinez. Thus, on the east line of Section 17, Twp. 19 S., R.
15 E., the base of the conglomerate is upon an oxidized zone and the
massive sandy shale immediately below the conglomerate is cut by num-
erous burrows that appear to have been made by crustaceans, in some
cases extending down to a depth of three feet. These burrow holes have
been filled with ferruginous sand and gravel congiomerates that are con-
nected directly with the overlying conglomerate. To the northeast, in
Twp. 17 S, R. 13 E, where the conglomerate rests upon the upper shale
of the Martinez, it contains shale inclusions at the base.

STRATIGRAPHY

The stratigraphy in the vicinity of Cantua and Salt Creek
is in a broad way simple; but in detail it is highly complicated (see
figure 9). Beds ranging in age from Jurassic-Franciscan to the
Pleistocene form a great eastward dipping monocline. The Shasta-

1916] Dickerson: Tejon Eocene of California 425

Chico series are overlain by Tejon Eocene which in turn is overlain
by white shales of probably Oligocene age. Middle Miocene strata, the
Temblor of Anderson, the Santa Margarita, the Etchegoin formation,
and the Tulare occur in succession, as one travels toward the San
of Dumble are divis-

?

Joaquin Valley. The ‘‘lower chocolate shales’
ible into two portions, the lower portion of which is characterized by
the abundance of nodules of barite, while the upper portion, which
yielded an Hocene fauna, is characterized by a sandy clay shale slightly
different in color and texture from the underlying chocolate shale of
probably Cretaceous age. This upper shale is decidedly glauconitic
and a two-foot bed of glauconitic sandstone charged with Turritella
andersont, n. sp., and many other Eocene fossils is another minor but
characteristic stratum. The unconformity described by Dumble is at
the base of Anderson’s Domengine sands, the beds beneath the white
shale. The evaluation of this unconformity will be discussed after
the faunas from the Domengine sands, and the underlying shales are
presented.

Kek

Fig. 9. Section showing Tejon group and associated strata in the vicinity of Domen-
gine Ranch, Coalinga Quadrangle. (After Ruckman.)

FAUNA FROM LOWERMOST BEDS

Turritella andersoni, n. sp. is found in great abundance in the
fauna from the glauconitic sandstone stratum mentioned above. This
new species gives a peculiar cast to this Eocene fauna and, taken
together with several new species in it made at first a very perplexing
problem. Large collections from Canada de las Uvas, the type local-
ity of the Tejon group, vicinity of Mount Diablo, San Diego, and
State of Washington have furnished such excellent comparative mate-
rial that the solution has been greatly simplified.

The species obtained from the lowermost horizon are as follows:

List or Species From UNIVERSITY OF CALIFORNIA LocaLity 1817

Type Turbinolia
Tejon Zone

ING UT OTd, eS IINCIGT. cece seecesec cence seco ce ce eee eneesee es
Trochocyathus imperialis Nomland .....................-.-..-.-
Miabellumi(?) merriami: Nonilamgl:..- 2.22.22... eee

426 University of Califorma Publications in Geology [Vor. 9

List OF SPECIES FrRoM UNIVERSITY OF CALIFORNIA Locality 1817—(Continued)
, Type Turbinolia

Tejon Zone
Turbinolia dickersoni Nomland es x
Turbinolia pusillanima Nomland x
COT a Se te Coy eres eens eee eee eee ee
Cidade G2) Spies a eee ee eee ecco ocean ee ae
INCU), Farol HME: Tah; 0, ee ee x x
HXa of ot emg) 1,6) 018 Way @ 21] 0) 0 aes ent i ec aa cesar eS ee x x
Cardium brewerii Gabb W222. ......c cece eeeeeeeeeee eee x
(@fzhi cob haba efayo) axeneatie (C200) 0): ese ee ee eee ee K x
Crassatellites lillisi, n. sp. —.....202022.....-. of LIE eee eres oe = =a
Cor bulamp arise Gail i gesecesceaecee eee ee eee eer x x
PO SUVA SS Ds C7) ie eee cere ees oe eens en eee = = a
GULYCIMETIS COT CG ab) eres cee cee eae ee enero x x
Glycimeris fresnoensis, Win Spy c22c-ce--c-ceeeecceecneeecaneceeeeee-- 2 ~
Giycimeris"sasittatus: C2) Gaby sccccceeeeceeeerseeessseoneceee x x
Isocardium tejonensis Warin ...........-.-22...:-----::---2eeeeee
OF best 0 hot Gad) amet 0 Vy ee Pca Scie ee rer arc NE reac ee
Meda freESMOenisis) Ws SDs josccccccccccccceccevecscecesnssecceecneneceecesee _ aaa
Meda sab Die © Om reat Chesser ccs eee tere cence aie ere x x
WE Habe Conazib ts) (Cys) a]a) See x x
MancialG?) COMMA Gite We tSI) 2 seeessre ce cece tener eer nee nee
Meretrix hornii GabD -20....... eee cette eneeeeee eee x x
Modiolus ormatus: (Gabi) ccccccecicc ce ececccececccee cece sceeseesesees * x
INUCUla COODERI WiCkersOm sei eee cc cece ccceree eres seeeereeeeee x
OStTEal SDs Aevvseccti ee ee Sree ee ee cn
Pecten, cf. interradiatus Gabb .....22-.2 2.0.00. eeeeeeeeeeeee
SOG TIS Dees oes ceatees carat een oeaer es eran
SUS ULE (23) mS JD eyecare ree see ene eee a
MOT GGOs SIO sscczec coerce eee wo, et eae oe ee a en sa
Venericardia planicosta hornii (Gabb)........0000.0000....... x x
Cadulus pirsilhis) Gab) ees ene ene ee x x
ATV AEE OD SUS aS tere eee eee eee ee ee ee a ae
Architectonica, cf. hornii Gabb x x
Ancillaria elongata Gabb _ x x
Bulilaiae Worm GG ai) ae seeen cece cece eae erence x =
Calyptraea excentrica (GabD) -22...0.022..2222222--cceeeeeeeeeeeeeeee x x
Cancellaria stantoni Dickerson..........00000.000020000222000.----- x x
(Olona ORsy Tavop anh LEGy oof ke eee eee ae ee x ae
Cydrehmamcostartam Ga D0 esse ecce eee x x
Chrysodomus supraplicata (Gabb) —......0..2..2.00-220-2------- x ‘x
Exilia perkinsiana (Cooper) x
Hicopsis) cle dorm ii (Grav eee ee x
A SEADESD WaTOUSH C209 leases) 0 ue sete Se MeN oe a As eee eR cee en ene
Guba wey. way berhCopcaawise (CF clo) See
MiltraaSimplicissimva COOp er eceseccetecesseteeeccceeeee eee eee
Metula shanrisivs mi 5SD icc sccersecceteseescnee eens eee
INabicase SeSterih a uS Dyce crescent ee
INViGtTLO CUS A 1SD i. (ais arccececeretreceec ce eee
INyctilochus; Spe (bi 222seccccteeceece sete me
Nyctilochus, cf. californicus (Gabb) x x

1916] Dickerson: Tejon Eocene of California 427

List oF SPECIES From UNIVERSIVY OF CALIFORNIA LocALiry 1817—(Continued)
Type Turbinolia
Tejon Zone

Nyctilochus, ef. whitneyi (Gabb) _....00.2...---2----.- x
INaticinamobliatiay Galli: meee es ee eee : ;
(OxokaysnmoyacwEy, yofenel ely vals fpoy, Ro ee ae Meee eee

Rimella simplex Gabb 00.0 ...222. 22222222 eee eee eee

UMC Uae LOG ab i. sercesse ct oc cee corte te reee Seer tee Ses cstes couse caeees ee

Terebra californica Gabb .....-......--.-2.--------c--c-e-e-eeceecnenoe

Turris guibersoni Arnold .........
Turris monolifera (Cooper)
TMUMTIS GSC ATS. (CC OOD CI) rea orc coca een ene ee
Turris fresnoensis Arnold ......-.2-..2--22--..2-2-.0--2eeeeeeeeeeeeee
HRA b eles speeds) 0 ya: 1 es Ace a ee a ps SP 1 ee eat
Turritella andersoni, n. sp. _..2-.-2------ee eee
WANCOT Gy CSD aah aces ore cee oe eee Secrest ere renee nee te eee
CORE W al eXen {C2 WARE Sy Ot ee eee

Trochocyathus imperialis Nom. oceurs at University of California
locality 1412 in the middle of the Tejon section south of Diablo.
Turbinolia dickersoni Nom., Turbinolia pusillanima Nom., Arca
hornn, Cardium cooperii, Cardium brewerti, Corbula parilis, Leda
gabbt, Meretrix ovalis, Meretrix hornii, Modiolus ornatus, Acila
gabbiana, n. sp., Venericardia planicosta horni, Ancillaria elongata,
Cylichna costata, Calyptraea excentrica, are forms which are found in
the Turbinolia zone south of Mount Diablo. Glycimeris cor, Glycim-
erts fresnoensis, n. sp., Architectonica hornii, Cancellaria stantoni, Co-
nus hornu, Odostomia packi, n. sp., Surcula vo, Ficopsis horni, Ficopsis
remondu, Cadulus pusillus, Lwnatia nuctformis, Mitra simplicissima,
Chrysodomus supraplicata, Nyctilochus californicus, Nyctilochus whit-
neyt, Naticina obliqua, Rimella simplex, Terebra californica, are all
characteristic forms at the type locality of the Tejon. Zsocardium tejo-
nensis Waring, Nucula coopert, Turris monolifera, Turris suturalis,
Turris perkinsiana, are all present in the uppermost or Siphonalia sut-
terensis zone, of the Tejon group. Twurritella andersoni, n. sp., is
found in the middle of the Tejon section south of Mount Diablo. Fla-
bellum merrianu, n. sp., Crassatellites lillisi, n. sp., Marcia (?) con-
radi, n. sp., Leda fresnoensis, n. sp. Metula harrist, and Natica, n. sp.,
are the only forms which have not been reported from the Tejon at
other localities or from the Martinez group. Nota single species which
is restricted to the Martinez group occurs in this fauna, and its rela-
tionship is undoubtedly close to the fauna of the typical Tejon which
is equivalent to the Rimella simplex zone.

Turbinolia pusillanima Nom., Cancer(?), sp. a are characteristic *
of the Turbinolia zone of the Diablo section (see fig. 1). This

428 University of California Publications in Geology (Vou. 9

fauna is tentatively placed as the equivalent of this zone. The writer
is inclined to regard it as slightly higher than the typical locality ot
the Turbinolia zone owing to the large percentage of species which
are present in the type Tejon.

FAUNA OF WHITE SANDSTONE MEMBER

Just below the white shales of Eocene-Oligocene age there is a
richly fossiliferous sandstone stratum. This stratum is ordinarily
firmly cemented, but at one small cropping, surface waters had in
some way removed the cement and left the shells in a perfect state of
preservation. Sixty-seven species were obtained from this locality
alone. They are listed below under Univ. of Cal. locality 672. This
fauna is evidently related to the fauna of the type Tejon, although
it contains about fifteen new species. The large number of new spe-
cies would be very puzzling if it were not for the presence of Turri-
tella wvasana and other species typical of the Tejon group. Turritella
uvasana is a good guide fossil for the middle portion of the Tejon
group, but it is not known to occur in the Siphonalia sutterensis zone
of California, and, if present in the Turbinolia zone, is rare.

A faunal list for the vicinity between Cantua and Domengine
creeks is given on pages 430-434.

The fauna found at locality 672 when compared with that of re
lowermost strata in this region (locality 1817) illustrates the marvel-
ous unity of the entire Tejon fauna. The number of species in common
is quite remarkable when one remembers that stratigraphic distance
between them is at least 2000 feet. Does this unity mean that only a
short geologic time is represented by the intervening strata? The
writer does not regard shortness of time as a plausible explanation,
but is inclined to believe that uniformity in climatic conditions in
upper Eocene time retarded the development of new forms.

Several workers in this field report the existence of a well marked
unconformity in the middle of the section. The time represented by
this unconformity is difficult to evaluate. The only method at present
available is the faunal one, and as has been previously shown the
faunas from above and below the unconformity are as a whole quite
similar. There is no well marked difference in dip and strike reported
along the unconformable contact, but the evidence consists of a sharp
change in lithology and the penetration of the underlying strata by
crustacean bore-holes which are filled with sand of the overlying

1916] Dickerson: Tejon Eocene of California 429

stratum. The unconformity reported is at least not of the same order
as the unconformity between the Tejon and Martinez, as the structural
and faunal break between these two groups is a great one. A very
large number of Martinez species failed to bridge the gap. Such is
not the case in the vicinity of Domengine Creek. The writer believes
that the time break represented by this unconformity is at most of
secondary order, ie., such as might separate two formations within a

group.
UNIVERSITY OF CALIFORNIA TEJON LOCALITIES IN COALINGA QUADRANGLE

All the following localities are in the Tejon group, Coalinga Quad-
rangle, Fresno County, California.
Twe. 18 SourH, Rancr 14 East, Mr. DiABLto Base LINE AND MERIDIAN.

670. Near W line of Sect. 15, on branch of Salt Creek 4% mile from Salt
Creek, in brown clay shale, 10 to 15 feet above the chocolate
Chico (?) shale, Turritella andersoni, n. sp. horizon. R. E. D. 592.
Colls. G. C. Gester and R. E. Dickerson,

671. NW corner, Sect. 24, 100 to 200 feet (stratigraphic) below white shale
—white Tejon sandstone contact. R. E. D. 591. Colls. B. Parsons
and R. E. Dickerson.

672. SH % of NW % of Sect. 24, Parson’s Peak, in Tejon white sandstone
0-10 feet below white shale. R. E. D. 590. Collis. J. A. Taff, G. C.
Gester, B. Parsons and R. E. Dickerson.

1817. SE 4% of NW % of Sect. 15, on branch of Salt Creek, near base of
Tejon, 75 to 100 feet above the chocolate shale of probable Chico
age, in a glauconitic sandstone stratum in clay shale. R. E. D. 586.
Colls. Miss Lillis, F. M. Anderson, G. C. Gester and R. E. Dickerson.

Twe. 18 SourH, Rance 15 Hast.
2266. SW % of SE % of Sect. 29, elevation 1150 feet. Coll. J. Ruckman.

Twre. 19 SoutH, RANGE 15 East.
2286. NE corner of SW 4 of NE \% of Sect. 9, in last inside-cafon north,
elevation 1300 feet. Coll. J. Ruckman.

Twe. 18 Souru, RANGE 15 East.

2287. SW corner of SW % of SE % of Sect. 29, in western side of Domen-
gine Canon. Coll. J. Ruckman.

2290. On crest of ridge overlooking Domengine Creek above apparent un-
conformity. Coll. J. Ruckman.

2291. NE corner of SE 4% of SW % of Sect. 29, elevation 1200 feet. Coll.
J. Ruckman.

2292. NW corner of NE % of SE &% of Sect. 32. Coll. J. Ruckman.

2293. Coll. Wm. Forker.

2294. Coll. Wm. Forker.

2295. Coll. Wm. Forker.

2296. Coll. Wm. Forker.

2297. Coll. Wm. Forker.

[VoL. 9

University of California Publications in Geology

430

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California 431

Tejon Eocene of

Dickerson

1916]

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University of California Publications in Geology [Vou. 9

432

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Tejon Eocene of California 433

Dickerson

1916]

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1916 | Dickerson: Tejon Hocene of California 435

WHITE SHALES

Mr. John Ruckman studied the white shales overlying the white
sandstone member and he found in the shales two faunas, one in their
lower portion which is apparently Tejon and another in the upper-
most stratum which is apparently Oligocene. The Tejon fauna was a
meager one consisting of Z'rochocyathus, ef. striatus, Crassatellites
mathewsonw and some indeterminate forms. <A portion of the white
shale may represent the Siphonalia sutterensis zone in this region.
Indirect evidence supports this view. The fauna from locality 672
contains several species which are common in the Siphonalia sutter-
ensis zone and their presence suggests that the fauna in the upper
portion of the white sandstone member is transitional between that of
the Rimella simplex zone and the Siphonalia sutterensis zone, i. e., it
may nearly correspond to the Balanophyllia zone of the section south
of Mount Diablo. (See figure 10.)

SUMMARY

1 The Eocene strata between Domengine and Cantua creeks,
Coalinga Quadrangle, belong to the Tejon group.

2 These strata appear to be equivalent to the Eocene strata in
the vicinity of Mount Diablo. They apparently represent a longer
portion of Tejon time than the Tejon of the type locality.

3 The fauna of the lowermost beds which is older than the
Rimella simplex zone, the fauna of the type Tejon, is tentatively cor-
related as the equivalent of the Turbinolia zone of the Mount Diablo
region.

4 The fauna of the white sandstone member is as a whole the
equivalent of typical Tejon, although the fauna from the uppermost
beds may be transitional between the Rimella simplex zone and the
Siphonalia sutterensis zone.

TEJON GROUP IN SAN Dizco County

The fauna of the Tejon group of San Diego County is a par-
ticularly interesting one, as it occurs in sediments which have
undergone but little folding or faulting. Diastrophism was not so
marked in southern California in post-Tejon time as in the central
and northern parts of the state. On this account, a correlation be-
tween the Tejon of San Diego County and the upper Eocene in the

436 University of California Publications in Geology Vou. 9

other parts of the state is important. The writer’s conclusions from
this faunal study are, in brief, that the Tejon of San Diego County
is the equivalent of the Tejon of the type locality, the Rimella Sim-
plex zone. (See figure 12.) No other zones of the Tejon group
were recognized in this region and no Martinez-Kocene strata were
discovered. This study shows that the diastrophic record in Southern
California has been quite a different one from that of the southern
San Joaquin in the vicinity of Canada de las Uvas, where Hocene
beds have been folded and faulted in an intricate fashion.

The occurrence of the Tejon group near San Diego was recognized
early by Gabb*? and Cooper.** Both Gabb and Cooper described
several species from the Tejon of Rose Canon. Fairbanks’! re-
ported both Tejon and Chico-Cretaceous from Point Loma, the con-
tact between the two being nearly at sea level. Arnold*® reported an
angular unconformity between the Tejon group and the Chico near
La Jolla:

It is a noteworthy fact that with one exception, wherever the line
between the marine Eocene formations (Martinez, Arago, Tejon, etc.) and
the Cretaceous beds are either of lower Cretaceous (Knoxville) or middle
Cretaceous (Horsetown) age, and that wherever the Eocene rests on the
Chico, or upper Cretaceous, excluding the case at San Diego, the un-
conformity is not angular, and as far as the stratigraphic evidence goes,
the two formations represent an apparently uninterrupted period of sedi-
mentation.

The one exception mentioned by Arnold is the Tejon-Chico rela-
tion at San Diego. It has been shown elsewhere that angular un-
conformities occur between the Eocene and Cretaceous in California
at several localities. Arnold’s discovery of the unconformity at
San Diego shows that the same condition prevails here as the writer”
has shown to exist in the vicinity of San Francisco Bay.

STRATIGRAPHIC NOTES

The Tejon in the vicinity of San Diego County is associated with
underlying Chico-Cretaceous, and with the overlying San Diego Plio-

72 Gabb, W. M., Geol. Surv. Calif. Palaeontology, vol. I, p. 95, 1864.

73 Cooper, J. G., Catalogue of California Fossils, Bull. No. 4, California
State Mining Bureau, p. 36, 1894.

74 Fairbanks, H. W., The Geology of San Diego, San Bernardino and
Orange counties, 11th Ann. Report Cal. State Mining Bureau, pp. 76-120,
1894.

75 Arnold, Ralph, Environment of the Tertiary Faunas of the Pacific
Coast of the United States, Jour. Geol., vol. 17, p. 513, 1909.

76 Dickerson, R. E., Fauna of the Martinez Eocene of California, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 8, pp. 61-180, 1914.

1916] Dickerson: Tejon Eocene of California 437

cene and Pleistocene terrace deposits. San Diego city is built upon two
or three marine terraces and the upper terrace, about 400 feet above
the sea, extends northward for many miles. Soledad Mountain,
which is five or six miles northwest of San Diego, rises above this
terrace, or rather the terrace encircles the mountain. The Tejon is
best exposed in the stream canons east of Soledad Mountain which
have trenched the marine terraces. Rose Canon and Tecolote Creek
yield particularly good sections.

The Tejon group in the vicinity of San Diego and La Jolla con-
sists of about 600-700 feet of nearly horizontal strata which underlie
most of the ‘‘
strata consist of beds of clay shale containing nodular limestone and

mesa’’ land around San Diego and La Jolla. These

dull red quartzose sandstone typical of the Tejon group throughout
the state. One prominent fossiliferous horizon is found about 200
feet above the base. This horizon occurs in Rose Cafon, Tecolote
Valley and in other valleys of the vicinity.

FAUNA

The fauna upon which this discussion is based was obtained
principally by W. 8S. W. Kew. The writer spent three or four days
in the field with Mr. Kew in the summer of 1913. Chester Stock
and Earl L. Packard also contributed to the collections from this
vicinity. Most of the specimens were obtained from the fossiliferous
horizon which is estimated as 200 feet above the base of the formation.
The collection obtained by Mr. Kew from Point Loma, University of
California locality 695, was near the base of the Tejon.

List or TEJON Fossits From LOCALITIES IN AND ArouND SAN DrEco

Type
694 695 696 697 2226 Tejon.
Aubdeaytihies koe - ee x — Pee = x
Astarte semidentata Cooper _.................... x eee ene tans x6 453
Acilarcabbianas is (SDigesssstee ceeeeen eee seeeeee x ae ac sere Ne x
Avicula pellucida Gabb ........000..0.202222------- xe x
Barbatia morsei Gabb ......002...0000.02200-2---e-e- ee ees aap eX
Corbula parilis Gabb —..00.0222222 eee < x a — xX
Cardium cooperii Gabb ........-00200..-2-22..- x a x pee x ~
Cardium brewerii Gabb ~........0000020220-2...-. Xe es x x ea ss
Crassatellites grandis Gabb _........-.-0....... > as ee a ee
CB EZ e(0 5 8 5 0 lpeaet =| 0 pee Reet Ose Rare CR =P nent we a oe = — oe 5 ae
Glycimeris sagittatus Gabb -.....00000000002000.... x aan _— Por x s<
Isocardium tejonensis Waring ................ x i ras: Bee —_
Lucina gyrata (Gabb) -0.00.2......200.2221222e eee oee oe2 x x

Lucina diegoensis, nN. SP. 2. eee oe x

438

University of Califorma Publications in Geology

List or TEJoN Fosstts From LOCALITIES IN

(Continued)

694
TDfeXe ke veckegey a ants (Cray ow ets le eee ee
Modiolus ornatus (Gabb) .......0........----...-.-
Meretrix hornii Gabb ..........2.002222 0...
Meretrix ovalis Gabb ............2..22.2.-2-000-------- x
Meretrix tejonensis Dickerson ...............
OSTA yy 3S Dryer meee x
Placunanomia inornata Gabb —.................. -..-
Papi: | Sip eextcrras: Sores se ton eer eee Dene eee
Spisula merriami Packard
SOIR gS Die erceetece sense ee ene a eee es ;
Solen parallelus Gabb ........0002..0002..2.---------2-2 eee
Macrocallista (Tapes) conradiana
(Ga) eee ee ee ae eee x
Psammobia hornii (Gabb) —............-.......- x
Tellina remondii Gabb ~..........000022-02-..-.....-- x
Tellina, cf. aequalis Gabb.......................--... x
FOU MTNa SS Din tea 2 nee oe eee een eee ee
MewWina, JOMACW SIS wt SD hesssceecesceeescseseese- ee eaes
Venericardia planicosta hornii (Gabb)..
Venus aequilateralis Gabb .....0.....000--.-000-. -.-
Dentaliumy sp.) Smooth =. ss
Dentalium stramineum Gabb ~................. *
Dentalium cooperii Gabb........0.00..0202020000002. -..-
Amphissa(?), sp.
Architectonica, sp.
Amauropsis alveata (Conrad)
Ancillaria elongata Gabb ..............--....----....
PNreolalyy evo oy aN ers lp ty Oey ey en pee ope
Cancellaria stantoni Dickerson -.........-.. -...
Chrysodomus supraplicata (Gabb) .......... x
Cylichna costata Gabb .......00222222222222--.------ x
Comms, Orman Ga cesses eee eseernce= scee scene ‘
Conus remondii Gabb ........02. eee x
Crepidula (Spirocrypta) pileum Gabb.... x
Cerithiopsis alternata Gabb —.........0-.... -..
Cypraea mathewsonii Gabb ~......2...2000......-.--
Calyptraea excentrica (Gabb) . .................
1025 18 Nes Hes 0 esse te ei et a mR RR a ae nS eerste ;
Galeodea tuberculata (Gabb) —....000.--0000-. -..-
Fasciolaria sinuata Gabb...................--.----- X
Fasciolaria bilineata, n. sp. -.............----....-- X
RT CODSIS SD. ecco cea cases econ cac eae
Ficopsis remondii Gabb ~.....0.....0.0-...---------
Hicopsis Cooperii ‘Gabbe eee
Fusinus, cf. martinez (Gabb) —....000000. -...
unatia, cf. Hormil\ Gabby eee x
Lunatia nuciformis Gabb ........020020..222--2-. ++

AND AROUND SAN

[Vou. 9

DiEGo—

Type

695 696 697 2226 Tejon.

x
x
y,
x oe
x x
x ae
Xx
x
x
x =
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x x x
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x

x

x XxX X

x

x?

x

SK XK SCE Ie x Gt

1916] Dickerson: Tejon Eocene of California 439

List or TrJon Fosstts From Locaniries IN AND AROUND SAN DrEco—

(Continued)
Type
694 695 696 697 2226 Tejon.
ioxotrema: turrita Gabb: .-.22-2c.ccceccecce-------t- =.= oe Ps x x
Mitra simplicissima Cooper —_.............-......
Mitra uvasana Dickerson ...............-.-....---. ----
Mitramorpha parsonsi, n. Sp. -...--..-...---22--. ----
Megistostoma striata Gabb...............-2.2........ ---- es — x
Mietula ech. WarriSiey We SD ctc-ceceeeseste- 222 coerce ee
Naticina obliqua Gabb ....................--.-...----- x
Natica uvasana Gabb ...............--..--sc-ee--<--- » a oe x
Natica hannibali Dickerson ......... + tS = a a x x
Nyctilochus diegoensis (Gabb) cae ee ee es x
Nyctilochus pulcher (Weaver) ...........-.... "Gouna vice See
Nyctilochus hornii (Gabb).....-.-.0--2000.-.-..... --.- “ X6 gee gee OX
Nyctilochus, ef. whitneyi (Gabb) —...... —.. “
INGViC GIO CINUIS HES Dy meeecsnceasceaee casas ctereees ee eee .
Olivella mathewsonii Gabb —..........-.000000.. -..- eee x ex
Pseudoliva volutaeformis Gabb —.............. XO ce ae Eg ee XK
Perissolax blakei (Conrad) ............--.-0.-. -..- fee x ae ren
Potamides carbonicola Cooper -
Pseudoliva inornata Dickerson ee a x
Rimella simplex Gabb —.............-....-...-...--- ae) Ae a x
Solariella crenulata (Gabb) ............-.------.. -..-
Seraphs erraticus (Cooper)...........-.-.....--.- x ee ee ues
Sureula (Surculites) sinuata Gabb ....... x ae a meee —_ x
Surcula cowlitzensis Weaver .................... > See ree,
Surcula supraplanis (Cooper) ............-... -..- Sie = heres aie x
Spiroglyphus(?) tejonensis Arnold......... —..
Turris fresnoensis (Arnold) .......... me pee ae — oe x
Turris, cf. andersoni Dickerson
DTT LO TUNIS) ee ee een eee
Turritella uvasana Conrad .................----.- x x Xs Ges x x
Turritella buwaldana, n. sp. ........2-..-...-----. x om ae ae x
Xenophora stocki, n. Sp. -....2.22--. eee eee
PASC ULTAT Ee SO boy tr escem etre eer erate Ce et Eee x a8 bt en eae
IN OU H UGS Shope et a ee ee — sie oo x

The fauna from locality 695 near the base of the Tejon is not
particularly different from the faunas at the other localities studied
and it is apparent from an examination of the list that but one zone
is represented in this vicinity.

COMPARISON OF FAUNA WITH THAT OF THE TYPE TEJON

The species which occur at the type Tejon are indicated in the last
column in the list given. Of the 79 forms specifically determined, 62
are reported from the Tejon of Canada de las Uvas. Astarte semi-

440 University of California Publications in Geology [Vou. 9

dentata Cooper, Ficopsis cooperu Gabb, are reported from the upper
part of the Umpqua formation in Oregon, Nyctilochus diegoensis
(Gabb) from the Siphonalia sutterensis zone at Oroville, Megisto-
stoma striata Gabb, Mitramorpha parsonsi Dickerson, from the top of
the white sandstone member of the Tejon north of Coalinga, Nycti-
lochus pulcher (Weaver), from the lowermost green shales of the
Tejon in the Pacheco syneline, Metula harrisi Dickerson from lower
Tejon strata north of Coalinga. Seraphs erraticus (Cooper) occurs
in the middle section of the Tejon south of Mount Diablo. Of all the
forms listed, Metula harrisi and Nyctilochus pulcher are reported
only from the lowermost zone of the Tejon group, the Turbinolia
zone. The great number of characteristic species common to the San
Diego Eocene and the type Tejon leaves no doubt as to their equival-
ence, and it is evident that the faunal stage represented at San Diego
is that of the Rimella simplex zone. (See figure 12.)

DESCRIPTIONS OF TEJON-EOCENE LOCALITIES IN SAN DIEGO
COUNTY

694. La Jolla Quadrangle, San Diego County, California. Tejon group.
Lat. 32° 47” 307; Long. 117° 11’ just east of Morena in Tecolote Canon.
Coll., Wm. Kew and R. E. Dickerson.

695. San Diego Quadrangle, San Diego County, California. Tejon
group. Point Loma. Coll., Wm. Kew.

696. La Jolla Quadrangle, San Diego County, California. Tejon group.
Lat. 32° 48’; Long. 117° 11”. N. E. of Morena in Tecolote Valley. Coll.,
Wm. Kew.

697. San Diego Quadrangle, San Diego County, California. Tejon group.
San Elijo Valley, McKinnon’s Ranch. Coll., Wm. Kew.

2226. La Jolla Quadrangle, San Diego County, California. Tejon
group. Lat. 33° 50’; Long. 117° 14’. Rose Cafon, S. E. of Soledad
Mountain and N. of Ladrillo Station on Southern Pacific R. R. Colls.,
Wm. Kew and R. E. Dickerson.

CONCLUSIONS

(1) The Tejon Eocene strata of San Diego County have yielded
a fauna of over 90 forms, many of which are common species in the
Tejon of Canada de las Uvas.

(2) The same faunal stage is present in both localities i. e., the
Rimella simplex zone.

(3) Orogenic movements in post-Eocene time have been far less
vigorous in the vicinity of San Diego than in central California,
although equivalent strata occur in both places.

1916] Dickerson: Tejon Eocene of California 441

TEJON OF THE SANTA ANA Mountains

The Tejon of the Santa Ana Mountains is intimately connected
with that of San Diego and it represents the Rimella simplex zone.
The stratigraphic relations of the Tejon was discussed in a recent
paper.”’ The fauna listed from University of California locality 2243
is as follows:

Cardium, cf. brewerii Gabb Cerithiopsis, sp.

Solen parallelus Gabb Cylichna costata Gabb
Tellina, cf. longa Gabb Ficopsis remondii Gabb
Cadulus pusillus (Gabb) Natica, sp.

Ancillaria, sp. Turritella, sp.

Bullaria hornii (Gabb) Turritella uvasana Conrad

This fauna appears to represent the Rimella simplex zone, as one
of its most characteristic species, Z'urritella wvasana, was fairly
abundant.

TrJon NEAR Lower Lake, LAkE County, CALIFORNIA

Rocks of Tejon age occupying an elliptical area two and one-half
miles long on the eastern portion of the Lower Lake syncline rest upon
the Martinez. Coarse gray to white, conglomeritic concretionary
sandstone which upon weathering gives rise to bluffs makes up prac-
tically its entire thickness, 1100 to 1200 feet. It is lithologically dis-
tinct from the uppermost Martinez, which consists of thin-bedded,
fine-grained, green-gray sandstone with green shales. No sharp con-
tacts between the Martinez and Tejon were found and hence their
relations to one another are not entirely clear. The dips in the Tejon
vary from 30° to 35°, while those of the Martinez are, on the whole
much higher. This, taken together with a distinct faunal break and
abrupt lithological change, leads us to believe that a considerable
time-interval elapsed between the deposition of these two groups of the
Eocene. Only two fossil localities were found in the Tejon. The
fauna found at University of California locality 785, which is about
900 feet above the base of the Tejon group, is as follows:

Crassatellites, cf. uvasana (Gabb) Meretrix hornii Gabb
Dosinia elevata Gabb Psammobia hornii (Gabb)
Spisula tejonensis Packard Solen parallelus Gabb
Meretrix ovalis Gabb Paphia, cf. cretacea Gabb
Meretrix, sp. Tellina longa Gabb

77 Dickerson, R. E., The Martinez and Tejon Eocene and Associated
Formations of the Santa Ana Mountains, Univ. Calif. Publ.. Bull. Dept.
Geol., vol. 8, pp. 257-274a, 1914.

442 University of California Publications in Geology [Vor. 9

Bullaria hornii (Gabb) Naticina obliqua Gabb
Cancellaria marysvillensis Neverita globosa Gabb
Dickerson Nyctilochus whitneyi (Gabb)
Drillia cooperi, n. sp. Surcula (Surculites), cf. sinuata Gabb
Fusinus californicus (Gabb) Whitneya ficus Gabb
Fusinus, sp. Serpula, sp.
Lunatia hornii Gabb Shark(?) tooth

Of the forms listed above, Dosinia elevata Gabb, Meretriz ovalis
Gabb, Solen parallelus Gabb, Tellina longa Gabb, Bullaria horn Gabb,
Cancellara marysvillensis Dickerson, Fusinus californicus (Gabb),
Naticina obliqua Gabb, Neverita globosa Gabb, Nyctilochus whitney
(Gabb), and Whitneya ficus Gabb are as far as known entirely typical
of the Tejon.

This fauna is too meagre for an accurate zonal determination.
Drillia cooperi, n. sp., is the only form which has not as yet been
reported from the type Tejon of Grapevine Creek. This form occurs
at University of California Locality 1853 in the Marysville Buttes.
Practically all the rest are long-range forms except Whitneya ficus,
which has not as yet been reported from the Siphonalia sutterensis
zone. The fauna does not contain many of the typical species in the
Rimella simplex zone, and but one characteristic species of the
Siphonalia sutterensis zone. This horizon on this account is tenta-
tively placed in the Balanophyllia variabilis zone.

SUMMARY OF TEJON FAUNA OF CALIFORNIA

The tables given below indicate the occurrence and distribution
of the forms which occur in the Tejon group of California. The local
occurrence of each species is given in the first major column and the
range of the species is indicated in the second. Four faunal zones
are recognized in the Tejon, a lowermost, the Turbinolia zone, then
the Rimella simplex zone, Balanophyllia variabilis zone and the
Siphonalia sutterensis zone, in order. These four zones do not occur
in any one locality unless all are represented in the Tejon north of
Coalinga, vicinity of Cantua Creek. In this locality the first three
appear to be present but the fauna which may represent the fourth
is too poor to lead to positive conclusions. The first three zones were
originally recognized in the area south of Mount Diablo and the
Siphonalia sutterensis zone in the vicinity of the Marysville Buttes
and at Oroville. The Rimella simplex zone is, however, more satis-
factorily shown at the type locality of the Tejon on Grapevine Creek.

x x KX xX

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1916]

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[Vou. 9

University of California Publications in Geology

446

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447

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1916]

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[Vou. 9

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Dickerson: Tejon Eocene of California 449

1916]

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453

Tejon Eocene of California

.

Dickerson

1916]

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454 University of California Publications in Geology

[Vou. 9

RELATION OF TEJON FAUNA TO MARTINEZ FAUNA

The relation of the Tejon to the lower Eocene (the Martinez) is

shown in the above table. The following species appear to be com-

mon to these two groups:

Schizaster lecontei Merriam
Cardium cooperii Gabb
Crassatellites grandis (Gabb)
Leda gabbi Conrad
Modiolus merriami (Weaver)
Modiolus ornatus (Gabb)
Acila gabbiana, n. sp.
Pecten interradiatus Gabb
Pinna barrowsi Dickerson
Psammobia hornii (Gabb)
Solen parallelus Gabb

Dentalium stramineum Gabb
Cypraea bayerquei Gabb
Cylichna costata Gabb
Calyptraea excentrica (Gabb)
Cerithiopsis alternata Gabb
Fusinus martinez (Gabb)
Fusinus mathewsonii (Gabb)
Lunatia hornii Gabb

Niso polita Gabb

Perissolax tricarnatus Weaver
Turritella conica Weaver

Marcia quadrata (Gabb)
Dentalium cooperii Gabb

Aturia mathewsonii Gabb

The following are questionable, as some are reported by Gabb only
from his ‘‘Cretaceous B’’ which sometimes included a portion of the
Martinez.

Cuspidaria dolbraeformis Gabb

Ostrea appressa Gabb
Flabellum remondianum Gabb

Avicula pellucida Gabb
Lunatia nuciformis Gabb

Collections made during the past two years emphasize the faunal
differences between the Martinez and Tejon rather than increase their
similarities. Many of the forms common to the two groups are general-
ized types and on this account survived through a long period of time.
Thus it is apparent that the Tejon fauna was evolved in part from
the Martinez and in part from other regions, particularly the Atlantic
via the Panama Portal, as there are a few species common to the Gulf
and Pacific Provinces. The general faunal development in the two
regions during upper Eocene time is very similar. The great develop-
ment of the genera Hvilia, Turbinolia, Thamnasteria, Turris, Conus,
Natica, Pseudoliva, Cypraea, Rimella, Tellina, Macrocallista, Meretriz,
and the abundance of species representing these genera are general
features which are far more characteristic of the Tejon than of the
Martinez.

RELATION OF TEJON FAUNA TO THAT OF THE SAN
LORENZO OLIGOCENE

As was stated above, the faunal relationship between the Tejon
and Oligocene of California is not very close. Cardiwm lorenzanum

1916] Dickerson: Tejon Eocene of California 455

(Arnold) may be a derivative of Cardiwm cooperii, as Arnold sug-
gested by its original name Cardiwm cooperw variety lorenzanum.
Aturia ziczac Sowerby which is reported from the San Lorenzo of
Santa Cruz County may be the same as Aturia mathewsonwu Gabb.
Calyptraea excentrica (Gabb) appears to be common to both the Tejon
and San Lorenzo. <A species of Solen which occurs in the Agasoma
gravidum zone at Walnut Creek closely resembles Solen parallelus
Gabb if it is not identical with it. The cast of the San Lorenzo fauna
of California is eocenic but any very direct connection between this
Oligocene fauna and the Tejon Kocene has not been discovered. This
lack of close faunal relationship seems to indicate that a time-interval
of considerable duration may have occurred between the periods, or
that a fauna which developed elsewhere may have entered suddenly
upon the opening of a portal which had been closed during Tejon
time or that both conditions as stated above may have taken place.
The writer is inclined to believe that a time-interval represented by
unconformity will be found although the invasion of a foreign fauna
may be an element as well.

SUMMARY OF STRATIGRAPHY

Typical Tejon sections are given below and a series of columnar
sections in figure 10 accompany them. The zonal divisions indicated
are only approximate, as fossiliferous Tejon horizons are not present
with sufficient frequency to warrant great accuracy. The broken
connecting lines indicate in a diagrammatic fashion the writer’s cor-
relations between the different sections in the state. The descriptions
of the sections are generalized in many eases.

Of these sections, the one north of Coalinga is probably most com-
plete stratigraphically, but the one south of Mount Diablo exhibits the
best faunal succession on the whole, and hence zonal divisions are more
accurately placed. In no one place is there a section complete in all
respects. Thus at Ione, Oroville and Marysville Buttes only the upper-
most phase, the Siphonalia sutterensis zone, is represented. At San
Diego and at Grapevine Creek, the type locality of the Tejon, only
the Rimella simplex zone is present. The upper Eocene in the Santa
Ana Mountains is probably but a residual of the same zone. Another
residual oceurs in northern California near Lower Lake and it prob-
ably represents portions of the Rimella simplex and Balanophyllia
variabilis zones.

-o eS Fic

AT a

|
ion |

1916] Dickerson: Tejon Eocene of California 457

I. Section Av MARYSVILLE BUTTES, CALIFORNIA

feet
(3) Green-gray sandstones and shales with limestone
concretions marking the upper limit of the
Tejon e LOX CSIING a ierreielied ta fete Econo sooner 100
Eocene (2) Green-gray, glauconitic shale 300
(1) Massive thin-bedded buff sandstone resting upon
Chico sandstone and limestone............................... 200
FL Orb alluzse-ceszsseeseee 600
Il. Srcrron NEAR OROVILLE, CALIFORNIA
Fae OLGEH gD aS allitrws- cece: eetesxcctac site ces Steve rens Pos: 20, ee esses see 100-150
[ (8) Andesitie tuff-breccia —...0222. een 10-20
(7) Alternating sandstone, clay and carbonaceous
S Tigi CS meme see ee ste as cece cee eins nee Saree ae ee es eee ae 100
GO): {@omnlelorm erate ace ae cose See wtees o e e 50
Tejon J D (G5 PTA CO OMS C) ay. eeste terre sees aces Sere eee eer ee er 200
Eocene 4 (4) Yellow tan sandstone 100
(3) Dark gray shales interbedded with lignite con-
taining fossiliferous strata and thin-bedded fos-
Siliferous Sandstone —....020.. 22.2.2... eee teen eeeeee eee enone 40
(2) Clay with tuff fragments —....2022222022222 22. 20
rf (1) Conglomerate resting upon Chico sandstone........ 20
PROG see ccocseeeeeze 530
III. Secrion ar IONE, CALIFORNIA
(5) Am desitie® tuttebnec Clacess.se seer ee ee
(4) Light gray clay rock, an altered rhyolitie tuff... 90
Tejon D (3) White or red sandstone.__._.......222222222t2--1eee eee eee eee 30
Eocene (2) Rhyolitic tuff altered to a clay containing a seam
OTE CO ei) eas erences Seo ae seas egrets See oe geese ees ee 180
(1) Conglomerate and sandstone......02-200002222.-- 800
Moai eee, 1100
IV. Secrion at Lower LAKE, CALIFORNIA
Tejon CG (QQ) Coarse gray to white conglomeritic concretionary
Eocene B a ESEEB GTO HSH C0) a1 en BP ee SPS ENT GE 1200
Martinez : : :
mMocatie of Thin-bedded, fine-grained, green-gray sandstone

458 University of California Publications in Geology [VoL. 9

V. *SECTION OF TEJON EOCENE, LILLIS RANCH, COALINGA DISTRICT

feet
(10) White shale
Olie White fossil organic shales, containing fish
deocene 4 scales, teeth, foraminifera, ete. —.......2.02.......... 500
Lenses of fine brown sand
Tejon . : F
Hoeene?: (9) White shales with local thin sandy strata.............. 1000
1 €8)' Local friable: Sava esessc srs eases ces eecsece tes cess ee 300
9
D?) (7) Pink to white shal@cccccccsccccccccocccssceccccscgsoecscesmseeseect 200
(6) Bluish sandy shales grading up into pink shales... 400
C J (5) White sandstone and conglomerate.........--....--.----- 100-160
{ (4) White massive sandstone and conglomerate with
whitish shale inclusions at the base...................... 20-40
(3) Upper chocolate shales, comprising bluish shales
at top, grading down into chocolate or brown
Tejon J shales which weather to clays. These rest upon
Eocene 2 B other chocolate shales which become sandier to-
ward bottom. These shales vary in thickness..600-900
(2) Yellow sand and conglomerate
Bluish sandy shales and thin sandstone, vari-
able ans GT CK CS Si eee eee rere eee ee 200
i Massive yellow sandstone with large dark brown
A segregations and concretions and some layers of
bluish sandy shale.
Fine sand with local beds of conglomerate inter-
bedded with blue and brown shales, a consider-
able amount of glauconitic material at base........ 300
Lower chocolate shales
Chico Beds of chocolate and brown shales with small
Cretaceous ferruginous and limy concretions and layers of
FEEHUUCLON aU IEC SED ON 0 eee 1000
Totalictn 22 3120

* Modified from Dumble’s section.

1916] Dickerson: Tejon Eocene of California 459
VI. SECTION OF THE TEJON GRouP SouTH or Mount DIABLo

Chico sandstone and limestone feet
(22) Massive tan sandstone. elec cece eee 225
2d) BT Wem Shall Gaetan eos 288 GR danas Ne noe ee 25
Ore (20) Massive tan sandstone................. 85
(19) Carbonaceous shales and lignite... 25
(18) Massive tan sandstone, third bluff..............02.. 554
((17) Carbonaceous shale and thin-bedded sandstone... 45
(16) Light gray sandstone 22002... tee eee eeeeeeee eee 8
(GS 3) Bis Taal] i een messi core ee tee a eee cog eae esas as 100
(14) Massive tan sandstone, second bloff........2..0..0000..... 390

(18) Massive soft sandstone with Turritella uvasana
execs (KeeKopalel ToVkonee ees ee eee 100

. (12) Thin-bedded sandstone with Turritella uvasana

Tejon 2

mosene < B DCU SHOMGCO Dimer c scence me aes tata eee ee eee peace 100
(11) Shale with thin-bedded sandstone........000000000000202.... 5
(10) Thin-bedded sandstone —20.00...0.00000200000022222eeeeeeeeeeee eee 50
(9) Sandstones with interbedded shales........00-000.... 307

(8) Alternating soft sandstones and carbonaceous
SEV Cs ie cea eR nee arene ene ase RNG SE oe Ue 200

| (7) Light tan coarse sandstone with cavernous
: weathering, first bluff 0. 125
(6) Gray-green foraminiferal shale —...222 0. 25
(5) Massive tan sandstone ~-..022..220202.2... einen eee 20
A 4 (4) Eland eray SanvdStome: serves cece core cece ve ececceeseses 40
(3) Gray foraminiferal shale —..... eee 75
. (2,1) Conglomerate and thin-bedded sandstone............ 25
SMO eH ee eee 2587

VII. Secrion or Tryon avr Types LOocaLiry

(3) Light tan sandstone and shale... eee 1200
Tejon (2) Thin-bedded brown sandstone with shale.......... 1000-1200

Eocene B (1) Coarse conglomerate composed of granitic rocks
resting on granite, basal member........................ 250-300
ADCo ez eee 2450

VIII. Secrion IN THE SANTA ANA MOUNTAINS

a (8) Fine-grained light tan sandstone containing an
abundance of fish scaleS.....0.....22222.20..ecceeeeeceeeeeee eee 250
(7) mCoarse Come om erea te seas scse cee eee eee 170
(6G) Wassivie white sandstone ce 400

Tejon B (5) Massive white and gray, medium-grained to fine
EHocene soft-weathering sandstone —...0002..000222 2022 300
) Shale and thin-bedded sandstone...........0......000-000---- 105
Medium-grained gray sandstone ~..............200-0--2..------ 85
2) Fossiliferous limestone -................ 2
L L ) Lignite and carbonaceous shale Le,

460 University of California Publications in Geology (Vou. 9

IX. SrEcTION IN RosE CANoN, SAN Dieco County feet

Tejon B Alternating beds of shale, white sandstone rest-
Eocene Ing: ON, CHICO -s:c2cciceerecnea 600

AREAL DISTRIBUTION OF TEJON GROUP

The Tejon has a much greater distribution than the Martinez,
which as far as known is confined to the San Francisco and Los An-
geles basins, small negative areas in the vicinity of these two California
cities. (See figures 11, 12, 13, 14.) No Martinez has been reported
from Oregon, Washington, or British Columbia, but the Tejon group
is represented by immensely thick beds in Oregon and Washington and
it is also found on Vancouver Island, as good specimens of J'wrritella
uvasana were collected by Professor Lawson from tuffs interbedded
with lava flows. The southernmost occurrence of the Tejon is at San
Diego. Tejon has been reported from Lower California at 29° 30’ N.
latitude but the few fossils reported from there are Martinez forms.
Tejon is reported from Round Valley, Mendocino County by Gabb.*®

Just what stage is represented is unknown, but the writer is in-
clined to think that it may be the Rimella simplex zone, as Gabb, who
knew the fauna of the type Tejon, said that there were several typical
Tejon forms present. The Tejon near Lower Lake is but a residual
and it has thus far yielded but a small fauna which has been placed
doubtfully as belonging to the third zone of the Tejon, the Balano-
phyllia variabilis zone.

The Ione facies of the Tejon group is found at several places in
the Redding quadrangle and it appears to underlie most of the coun-
try covered by later tuffs and lavas. This uppermost phase of the
Tejon Eocene, the Ione, has yielded the Siphonalia sutterensis fauna.
In the upper Sacramento Valley on both the west and east sides
as well as the north end, the Jone is but gently inclined. Dips of but
1° or 2° are usual in the littoral deposits beneath the basalt of Oroville
South Table Mountain. <A similar condition is found along the eastern
border of the Great Valley. At Marysville Buttes the off-shore phase
of the Siphonalia sutterensis zone is found in deposits which dip in
all directions from the andesitic stump of this ancient voleano. The
Tejon of Lower Lake, which is about west of the Marysville Buttes,
is gently folded in the syncline near Lower Lake in marked contrast

78 Gabb, W. M., Geol. Surv. Cal. Palaeontology, vol. 2 (preface, p. 13), 1869.

1916] Dickerson: Tejon Eocene of California 461

to low dips of the Ione of the north Sacramento Valley. Evidently
folding and faulting in post-Ione time in the Coast Ranges has been
quite vigorous in contrast to the slight changes in the Klamath
Province.

As will be shown later, the physiographic provinees of California
were inaugurated in Eocene time and a part of the diastrophic move-
ments which have determined these provinces actually took place dur-
ing the Eocene.

Diller’? recognized the Ione formation on the west side of the
Sacramento Valley in the vicinity of the Cold Fork of Cottonwood
Creek, Tehama County.

On Cold Fork, however, only a few miles further north, the exposures
are good and thirty feet of the Ione formation was seen. It is composed
chiefly of yellow gravel, but is separated from the overlying tuff by a
stratum of clay about a foot in thickness. Here the Ione formation ends
abruptly against a steep slope of the Cretaceous strata upon the edge of
the base level of erosion, but the overlying tuff and Red Bluff formation
lap over upon the base level, showing that they are of later origin.

On Salt Creek, about six miles north of Cold Fork, the Ione forma-
tion has the largest exposure seen on the western side of the Sacramento
Valley. Immediately beneath the tuff there is sixteen feet of clay, which
is underlain by forty-eight feet of sand and gravel beds, making a total
thickness of sixty-four feet exposed. The gravel predominates and the
pebbles increase in size toward the base. Similar sections are seen in
Dry Creek, Roaring River, and the North Fork of Cottonwood Creek.
In every case the bed lying immediately beneath the tuff is a layer of clay.
This top bed of clay extends further westward upon the edge of the
base level than any of the other beds, and the whole formation rapidly in-
creases in thickness toward the Sacramento Valley. In some cases the
tuff and graveis of the Red Bluff formation lap over upon the base level
plain for several miles, but the Ione formation stops at its edge.

Judging from Diller’s description, the shore line of the Eocene
sea was marked by these deposits along the edge of the Klamath
peneplain. The occurrence of marine Ione at Oroville and at Marys-
ville Buttes has been described in detail above. It seems probable
that there was not an extensive land-mass west of the Marysville
Buttes, as the Hocene deposits in this vicinity were laid down in
water about one hundred fathoms in depth along the edge of the
continental shelf, as is evidenced by the abundance of glauconite and
by certain deep-water facies exhibited by the fauna.

South from Oroville unmistakable strand-line conditions have
been recognized at Ione, Merced Falis and Bear Creek, Merced

79 Diller, J. S., Topographic Revolution on the Pacific Coast, Fourteenth
Annual Report U. S. Geological Survey, p. 455, 1894.

462 University of Californa Publications in Geology — |Vou. 9

County, as were described above. Whitney®® describes the region
further south as follows:

From Kern River to Kings River, the metamorphic and granitic rocks
continue into the valley until covered by the recent detritus; but north
cf Kings River, as far as the Stanislaus, there is a belt of low flat-topped
and dome-shaped hills of sandstone, rising one hundred to one hundred
and fifty feet above the level of the plain. A little north of the Merced
River, to the west of the road from Bear Valley to Stockton, a very hand-
some variety of sandstone was observed, forming low cliffs near the sum-
mit of a hill about one hundred and fifty feet high. This rock was a
fine-grained free-stone, elegantly ornamented with fine, waving and con-
centric lines and bands of a light rose-red color. For some kinds of archi-
tectural purposes, this stone would be a very desirable material.

Such is the basis for the strand line to Kings River on the east-
ern side of San Joaquin Valley.

Large collections from the type locality of the Tejon group made
by Mr. Bruce Martin of the California Academy of Sciences and by
the writer, do not contain the Siphonalia sutterensis fauna. Mr.
Clark Gester reports much thicker beds of Tejon north of the
Canada de las Uvas in the vicinity of San Emigdio Creek and certain
white shales in this vicinity may represent the equivalent of the
Siphonala sutterensis zone.

Mr. John Ruckman found Trochocyathus, ef. striatus (Gabb) and
Crassatellites (Astarte) mathewsonu (Gabb) in white shale beds imme-
diately overlying the white Tejon sandstone in the Coalinga district
near Domengine Creek. The coral is not definitely determinable, but
it resembles Trochocyathus striatus, a characteristic form of the
Tejon. The shales are somewhat ashy and they may represent
reworked rhyolitic ash of the Sierra Nevada. The upper portion of
these beds yielded Mr. Ruckman a small but characteristic fauna of
Oligocene age, San Lorenzo stage. The Tejon fauna below the white
shale is about the equivalent of the Balanophyllia zone, Mount Diablo
region, which is between that of the type Tejon and the Siphonalha
sutterensis fauna. No other lecalities in which the uppermost zone of
the Tejon is found are known in the Coast Ranges of California. Some
residuals may yet be found, but apparently the uppermost strata of
the Tejon were removed at least in large part during the great inter-
vals of erosion between the Eocene and Oligocene, and Oligocene and
Miocene. According to Fairbanks,*! no Tejon was deposited within

80 Whitney, J. D., Geological Survey of California, Geology, vol. 1, p. 202,

1865.
81 Fairbanks, H. W., San Luis Folio, No. 101, U.S. Geological Survey, p. 3,

1904.

1916] Dickerson: Tejon KHocene of California 463

the area of the San Luis Quadrangle and he states that the area was
probably an insular mass during Eocene time. No Eocene is reported
from the San Juan district in southeastern San Luis Obispo County.

The coal of the Stone Cafion area in the southeastern corner of
Monterey County is Miocene in age and not Hocene. Eocene deposits
are lacking in this area and in the rest of the Priest Valley Quadrangle
to the north. So far as known, Monterey County does not contain
deposits of this age within its borders.

South of the San Luis Quadrangle, great thicknesses of Eocene
strata which are at least in part Tejon were reported by Eldridge.**

Lawson** mapped no Tejon in the Mount Tamalpais Quadrangle.
No Tejon has been reported from Sonoma County.

The Tejon occupies quite extensive areas in Napa and Solano
counties and the three lower zones are probably all represented. Just
south, in the Concord Quadrangle, the Tejon has a thickness of about
2000 feet. The lowermost zone, the Turbinolia zone, and the second,
the Rimella simplex zone, are present. The third zone, the Balano-
phyllia variabilis zone, may be represented by the non-fossiliferous
beds at the top of the Tejon in this vicinity. The Turbinolia, the
Rimella simplex, and the Balanophyllia variabilis zones have their
type localities in the area south of Mount Diablo. The uppermost, or
Siphonalia sutterensis zone, appears to be entirely absent in the
San Francisco Bay region. The reason for this will be discussed later.

The Ione phase of the upper Eocene is found along the eastern
side of the Great Valley from Oroville to Fresno River but the other
zones are missing here. On the western side of the Great Valley,
Tejon is found at frequent intervals from Mount Diablo to the
Tehachapi Mountains. At least three zones of the Tejon are present in
the Temblor Mountains in the Coalinga District and possibly the
uppermost may be represented by a portion of the white shales in the
oil fields of Coalinga. At the type locality of the Tejon in the
Tehachapi Mountains only the Rimella simplex zone is present.

Along the coast from Mendocino County to southern San Luis
Obispo County, no Tejon has been reported, but the non-fossiliferous
Butano formation of the Santa Cruz Quadrangle may belong to this
group. West and south of the type locality of the Tejon, however,

82 Eldridge, G. H., and Arnold, R., The Santa Clara Valley, Puente Hill,
and Los Angeles Oil District, Southern California, Bull. No. 308, U. S. Geo-
logical Survey, pp. 5-7, 1907.

83 Lawson, A. C., San Francisco Folio, No. 193, U. S. Geological Survey,
1914.

464 University of California Publications in Geology [Vou. 9

extensive deposits of Tejon strata are found in the Santa Maria and
Santa Clara Valley oil districts. Tejon is reported from the Calabasas
Quadrangle a few miles northwest of Los Angeles. The faunal
stages represented here are somewhat doubtful but intensive study
in this field will probably show the presence of a very complete faunal
sequence. From a cursory examination of faunas from this region,
the Turbinolia and Rimella simplex zones appear to be represented.

Tejon Eocene appears to be present on Tully’s Ranch on Bitter-
water Creek, San Benito County, according to the work of the geolog-
ical staff of the Union Oil Company. This locality is only a few miles
north of Stone Canon and is probably a residual.

The reconnaissance work thus far done in the Santa Lucia Range
in western Monterey County has not resulted in the discovery of any
rocks of Eocene age. Lawson reported the Carmelo series as ques-
tionably Eocene, but he is not inclined to this opinion now.

The small outliers of the Tejon in the Santa Ana Mountains and
the gently dipping sandstones of the San Diego Eocene represent the
Rimella simplex zone. Such in brief is the known distribution of the
beds of the Tejon group in California.

The absence of the Tejon group from the outer Coast ranges of
California from Cape Mendocino to the Santa Maria River in Ventura
County is very remarkable. Two explanations are possible: (1) the
Tejon was never deposited over the site of the outer ranges such as the
Santa Cruz Mountains and the Santa Lucia Range, but the upper
Eocene sediments were deposits in a great sound which opened widely
to the south, (2) the Tejon was deposited by a transgressing sea and
its sediments were removed in post-Tejon time. Lawson** has discussed
these two hypotheses for the San Francisco Bay region in connection
with the deposition of the Miocene as follows:

In the Bear Creek anticline, in the northwestern part of the Concord
Quadrangle, the lower Monterey strata rest upon the Tejon, but here the
structure of the Tejon is so obscure that it is not possible to discover
whether or not there is structural discordance, and no conglomerate has
been observed at the base of the Monterey. The consideration of these
three sections thus affords evidence of no very profound degradation of
the Tejon in the pre-Monterey interval of uplift.

In the section exposed in the Berkeley Hills, however, about five miles
southwest of the Bear Creek anticline, the Monterey rock rests directly
upon the Chico. Both Tejon and Martinez are absent. The Claremont
shale, the second formation of the Monterey group, lies almost in direct

84 Lawson, A. C., The San Francisco Folio, U. S. Geol. Surv. Folio 193,
p. 10, 1914.

1916] Dickerson: Tejon Eocene of California 465

contact with the Chico, the Sobrante or basal sandstone of the Monterey
group being represented by only a thin layer of yellow incoherent sand-
stone, mapped with the Claremont. There are no conglomerate beds at
the base of the Monterey in this section, for here the Hocene rocks,
which are more than 4000 feet thick 9 or 10 miles farther northeast, either
were not deposited or, as seems more probable, had been completely
removed in pre-Monterey time. One justification for the view that the
Eocene rocks once extended over the region of the Berkeley Hills and
were removed in the Eocene-Miocene interval is that this part of the Coast
Ranges contains no representative of the San Lorenzo formation (Oligo-
cene), which occurs to the thickness of 2500 feet in the Santa Cruz Quad-
rangle. In San Lorenzo time the Berkeley Hills region was probably a
zone of erosion.

The fifth section in which the Monterey is exposed in superposition
upon older rocks is at Selby, on San Pablo Bay, in the Napa Quadrangle
a few miles north of the San Francisco Quadrangle, where a well-defined
unconformity is revealed in a cliff. The surface upon which the Mon-
terey rocks rest is a wave-cut terrace, perforated by many holes made
by boring molluses. The strata in which this terrace is cut are soft
black shales, which are probably Martinez in age, for Martinez fossils
have been found in the sandstones that adjoin them on the north. These
shales have a southerly dip of about 70°, and the surface of the per-
forated terrace and the superimposed sandstones of the Monterey dip
in the same direction at about 60°. It is evident that the shales were
elevated above sea-level and inclined at about 10° to the horizon when
they were truncated to form the terrace. The sandstone of the Monterey
contains a fossil fauna which, in the opinion of Professor J. C. Merriam,
is that of the middle Monterey. The Tejon is apparently absent here,
although it is abundantly represented only a few miles to the southeast,
along the strike of the rocks. The Monterey sea evidently did not extend
over this part of the region until middle Monterey time, and therefore
part of the erosion is referable to early Monterey time. In general, how-
ever, the historical facts that are so clearly manifest at Selby are con-
sistent with and support the interpretation of the section in the Berkeley
Hills, where the Monterey rests directly upon the Chico.

The middle Miocene, Turritella ocoyana zone, in the vicinity of
Stone Cation in Monterey County rests directly upon the Franciscan
and upon remnants of Chico without any intervening Kocene strata.
This region is west of the Coalinga District where the Tejon is fairly
well exposed. Fairbanks** reported no Eocene in the San Luis Quad-
rangle, but the Miocene rests upon granite, Franciscan, Knoxville or
Chico indifferently. He described conditions as follows:

With the close of the Cretaceous and the advent of the Tertiary a
marked change took place. The region of the Coast Ranges began to
rise and the ocean was excluded from the greater portion of it. The
water continued, however, to occupy Sacramento and San Joaquin Val-
leys, maintaining an outlet to the south across Ventura and eastern

85 Fairbanks, H. W., San Luis Folio, U. S. Geol. Surv. Folio No. 101,
p. 9, 1904.

466 University of California Publications in Geology (Vou. 9

Santa Barbara Counties. This view is based upon the fact that within
the San Luis Quadrangle, as well as northwestward through the heart
of the Coast Ranges, the Eocene, or Tejon formation, is entirely absent,
while on the borders of the Great Valley and southward across the Coast
Ranges the formation is extensively developed. The Eocene, then, in the
region under discussion was an epoch of erosion, and it was during this
time that large portions of the earlier formations were removed. The
region was probably reduced to one of low relief, and the waste material
was deposited beyond the present shore line.

Decisive direct evidence upon this question can be obtaimed only
by careful mapping of large areas. In the vicinity of Stone Cafion,
Monterey County, the areal and structural relations of the Miocene
to the Franciscan and Cretaceous indicate a very great period of
erosion between the deposition of the Chico-Cretaceous and the Miocene
sediments. This is shown by the residual nature of the Chico ex-
posures in many places and by pre-Miocene folding.

The fauna of the Tejon in the Coalinga District which is east of
the San Luis Quadrangle contains such genera as Spatangus,
Trochocyathus, Balanophyllia, Turbinolia, Spisula, Turris, Fusus
and Surcula, in abundance. These genera are more characteristic of
an archipelago or open-ocean habitat than that of a sound. Such
gvenera as Barbatia, Potamides and Corbicula do occur, but in most
cases strata containing such an assemblage are limited in extent and
probably represent estuarine deposits near the mouths of the Eocene
rivers.

Rocks derived from the Franciscan, Chico, and Martinez groups
form the conglomerate boulders in the basal Tejon member north of
Mount Diablo. Their occurrence suggests the existence of a con-
tinental land-mass a short distance east of the present site of Mount
Diablo or of islands in this vicinity. The absence in this region of
uppermost Tejon sediments, their presence forty miles eastward, and
the direct field evidence in the Ione facies of the Tejon Eocene which
demonstrates deposition along a shore line by a transgressing sea can
be easily explained by a great interval of erosion in post-Hocene time
during which all the Tejon sediments were removed from the outer
ranges and the uppermost sediments from the inner of the Coast
Range. An unconformity between the Oligocene and the Tejon at
Walnut Creek indicates that this condition existed, for the upper-
most Tejon strata contributed coal and sandstone to the basal conglo-
merates of the Oligocene. The Tejon was possibly exposed to subaerial
erosion during another long period of time which in certain places is

1916] Dickerson: Tejon Eocene of California 467

represented by unconformity between the Miocene and Cretaceous.
Both time-intervals were apparently very long ones. They were so
long that but few Tejon species persisted into the Oligocene, and
none into the Miocene. When one remembers that the Tejon fauna
contains at least 300 to 400 mollusea, the length of time represented
by these two unconformities is quite sufficient to account for the re-
moval of the Tejon by erosion from the present sites of the moun-
tains bordering the Pacific. The distribution of Tejon sediments, the
absence of the Siphonalia sutterensis zone in the Mount Diablo region,
the presence of a typical marine fauna in most horizons of the Tejon
and the existence of two periods of erosion between the Tejon and
Miocene, lead to the conclusions that the Tejon was deposited by a
transgressing sea and that Tejon sediments were largely removed from
the outer Coast Ranges during post-Tejon and pre-Miocene time. The
existence of islands upon a wide continental shelf is possible, but if
they existed they were not sufficient in number or extent to prevent
the free access of the Eocene ocean.

GEOGRAPHY OF THE TEJON SEA

During the whole of Eocene time in California the San Fran-
cisco Basin*® was a negative area, and for this reason the Eocene
record of deposition is most complete in this portion of California.
This basin was small during Martinez time, being merely an open
bight extending from the vicinity of Lower Lake in Lake County
to about the southern boundary of San Mateo County. The most
easterly point in the basin in Martinez time was probably a few
miles east of Benicia. After the recession of the sea at the close of
Martinez time, mountain-making movements were moderately active
and the Martinez strata were folded and eroded. Again, the San
Francisco Basin was an area of sedimentation at the beginning of
Tejon time. Apparently the Eocene sea during early Tejon time
transgressed upon the land in the San Francisco Basin to a far
ereater extent than during Martinez time. The Tejon sea probably
extended from the vicinity of Round Valley, Mendocino County, to
the vicinity of Coalinga. The data upon which this is based was given
above. During Tejon time, numerous local oscillations occurred.
The sedimentary record on the north and south sides of Mount

86 Dickerson, R. E., Fauna of the Martinez Eocene of California, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 8, No. 6, pp. 69-71, 1914.

468 University of California Publications in Geology [Vou. 9

Diablo and in the vicinity of Coalinga register these oscillations by
local unconformities, which indicate a fluctuating condition of the
strand line, the major movements being those of subsidence. Ap-
parently this subsidence continued and the consequent transgression
ot the sea caused the sediments which contain the Siphonalia sut-
terensis fauna to be laid down upon the western foothills of the
Sierra Nevada.

The Los Angeles Basin during Eocene time appears to have
undergone movements quite different from those in the San Fran-
cisco Basin. So far as known, the Tejon sea did not extend as far
eastward as the Martinez sea and only the middle portion of the
Tejon was deposited along a strand line which extended only five to
ten miles east of the present coast. The Tejon fauna of San Diego
County represents only the middle zone, both the lowermost and
uppermost zones being lacking. It seems very doubtful if either was
ever present. Orogenic movements have not been as vigorous in
Southern California since the deposition of the Tejon as in Northern
California, since the beds at San Diego and in the Santa Ana
Mountains are but slightly inclined. In brief, the movements in the
two basins were just opposite, the Martinez exhibiting the greater
subsidence in the Los Angeles Basin, the Tejon in the San Francisco
Basin.

The presence of islands is suggested by Fairbank’s work. A wide
channel probably connected the Tejon Eocene of the San Joaquin Val-
ley with that of the Santa Clara Valley of the south. These islands
were probably somewhat similar to the Channel Islands of southern
California. No large land-locked bays appear to have been present in
the southern portion of the San Francisco Basin during Tejon time,
as the marine faunas are not, broadly speaking, estuarine but those of
a more open coast. Coal seams, however, do occur locally at several
horizons in the Tejon with an associated estuarine fauna. They prob-
ably represent sedimentation at the mouths of large rivers which
flowed westward from the Eocene Sierra Nevada.

The earliest sediments of the Tejon Eocene were deposited in an
enlarged, elongated San Francisco Basin (see figure 11). The
northern extent of this area of deposition is doubtful, but it probably
extended as far north as Mendocino County. The Turbinolia zone is
typically represented south of Mount Diablo and it also occurs in the
vicinity of Coalinga. It is probably represented in Santa Barbara
County at the base of the so-called Topatopa formation.

1916] Dickerson: Tejon Eocene of California 469

%

yore, &

pear} FR bie Blo
— th

oat é % WAG

Vay
Aa chs =
acramento , pA ig
wns)
’

a ne

a>
aN. et
IR
Weer

Fig. 11. Map of California showing probable extent of the Tejon Sea during the
deposition of the rocks containing the Turbinolia fauna.

470 University of Califorma Publications in Geology [VoL. 9

~ 4_¥.
eee rb-s
acramento poy Y2>..
iy ltrs We
Ye “Berkeley
a. fe

NN? Oakland

a
poss

4 ae aie ae =
js SAN GABRIEL rg, Sy ee
oo ht SAN ea
WExted my BE

o

aagas A

hy yt

2

.
2

“Be
(

aa (
S

Fig. 12.

Map of California showing probable extent of the Tejon Sea during the
deposition of the rocks containing the Rimella simplex fauna.

1916] Dickerson: Tejon Eocene of California 471

Without any marked change in deposition and without any appar-
ent unconformity between the Turbinolia Zone and the Rimella
simplex Zone, the sediments containing the Rimella simplex fauna
were laid down on top of the earlier sediments in the San Francisco
Basin. By gradual enlargement of the San Francisco Basin through
sinking and the consequent transgression of the Tejon sea, the shore
line was extended in this basin further east, further north and further
south across the present site of Canada de las Uvas, the type locality
of the Tejon. At this time the Los Angeles Basin again became an
area of deposition as is shown by the Tejon sandstones of the Santa
Ana Mountains and of San Diego County (see figure 12). The
deposition during this period was probably interrupted by slight up-
lifts followed by shght depressions and the shore line was a decidedly
shifting one as is indicated by slight, local uneconformities south of
Mount Diablo and by the alternations of estuarine and marine faunas.

Apparently the Los Angeles Basin did not remain beneath the sea
during the deposition of the rocks containing the two succeeding
faunas, as the Rimella simplex fauna is the only one represented there.
The Balanophylha zone is typically represented in the Mount Diablo
region, and probably occurs in the vicinity of Lower Lake as well.
The fauna from the top of the white sandstone member of the Tejon
north of Coalinga represents this zone. Apparently the present site
of the Tehachapi Mountains was a land-mass at this time. Land con-
ditions probably extended for fifty miles further north, shutting out
the Tejon sea from the vicinity of the type Tejon.

The San Francisco Basin was still further lowered to receive the
sediments containing the Siphonalia sutterensis fauna and the ad-
vancing shore line of the transgressing Tejon sea moved farther and
farther to the eastward and the golden sands of the earlier gravel
period and the rhyolitic tuffs were deposited across the truncate
edges of the Mariposa slates and associated intrusives of the Bedrock
series. Far to the north between the Klamath and the Sierra Nevada
a great bay extended and estuarine deposits were laid down across the
present site of the town of Redding. Into this bay and the Tejon-
Pacific Ocean the rivers of the Klamath Mountains and Sierra Nevada
plunged rapidly, bringing with their waters the sands and gravels.
According to Diller, the Klamath Province was a peneplain at this
time and according to Lindgren the Sierra Nevada region had ad-
vanced in topographic development to middle or late maturity with

472 University of California Publications in Geology

[Vov. 9

308 \ \-

yi

LL’

a
S

\ Ye. : Ptr, a
i ARS he
BATS ear} f AeA

‘

; d Tahoe

r
—~ x
\ “pe ear
2 Soy
acramento , p= ww ft
\ \ Geka TO geo
= \ ray g Sib pe
y aii 4s 3 rice
i \ ID ¥

Sie ©
Ni, EEN
\ Sass "°S

San Francisco Pye

Oakland

Hiss, 13:

Map of California showing probable extent of the Tejon Sea during the
deposition of the rocks containing the Balanophyllia fauna.

1916] Dickerson: Tejon Eocene of California 473

ing :
a hal Kamath ;

[ese

Fig. 14. Map of California showing probable extent of the Ione-Eocene Sea.

1. Tejon of Round Valley, Mendocino County; 2. Ione-Hocene, Cold Fork of Cotton-
wood Creek, Tehama County; 3. Ione-Hocene, near Oroville; 4. Ione-Eocene of Marys-
ville Buttes; 5. Ione-Eocene at Ione, Amador County; 6. Ione-Hocene near Merced
Falls; 7. Ione-Eocene near Kings River; 8. Tejon group at Lower Lake, Lake County;
9. Tejon group, vicinity of Mount Diablo; 10. Tejon group, Coalinga District; 11. Stone
Cafion, Monterey County, Cal.; Hocene, absent; 12. San Luis Obispo County; Eocene,
absent; 13. San Juan District, San Luis Obispo County; 14. Tejon group, San Emigdio
Creek; 15. Tejon group near Lompoc, Cal.

474 University of Califorma Publications in Geology (Vor. 9

crest line mountains of 3000 to 5000 feet. These mountains and the
numerous moderately wide valleys of short, consequent westward-
flowing streams were covered by great forests of subtropical plants in
the lowlands and coniferous forests along the crest of the Eocene
Sierra Nevada. Remains of these plants have accumulated in sufficient
quantity to form a 12-foot seam of Ione coal. During this period great
rhyolitic ash and mud flows changed the whole appearance of the
western Sierra Nevada, filling the valleys to their brims and vastly
altering the drainage.

This great rhyolitic period was interrupted long enough for the
development of new drainage systems as represented by the inter-
rhyolitie channels and their correlative marine lone sandstones. After
this, a period of erosion ensued and then the andesitic tuffs, lavas
and mud flows covered all, extending even beyond the border of the
eastern edge of the Great Valley as is shown at Lincoln, Sacramento
County. Basalt of approximately the same age as the andesite capped
the Eocene deposits in places. This great thickness of lavas formed a
protective coating and preserved the latest Tejon, the Ione, from
erosion along the eastern border of the Great Valley. In the Coast
Ranges farther to the west, the sediments containing the Siphonalia
sutterensis fauna were probably not so thick, for they were laid down
in deeper water and in general lacked a protective lava capping.
Hence their rapid disappearance over most of this area.

CORRELATION
HUIstToRICcAL

The correlation of the Tejon with the Claiborne Eocene of the
Gulf States was suggested by Conrad upon his first examination of
the fossiliferous boulder from Canada de las Uvas which was sent by
Blake. Dall, Heilprin, Clark, Harris, and Arnold have all made ten-
tative correlations. Most of these have been based upon the identity
of a few species and the recognition of equivalent faunal development.

Conrad*’ reported Natica aetites, Natica gibbosa, V enericardva
planicosta, Crassatella alta, of the Claiborne Eocene as being present
in the Tejon of the type locality. None of these is strictly identical
with the corresponding Tejon form.

s7 Conrad, T. A., Pacific Railroad Reports, App. to Prelim. Geol. Rept.
of W. P. Blake, Palaeontology, pp. 5-20, 1855.

1916] Dickerson: Tejon Hocene of California 475

Heilprin*® was the next writer to point out faunal similarities. He
compared Cardita planicosta Gabb with the typical V. planicosta and
agreed with Gabb that there was a difference in the shape of the ribs.
““Dosinia elevata Gabb appears to be very closely allied to the Dosv-
niopsis meeki of Conrad of the lower Eocene of Maryland and Vir-
ginia.’’ ‘‘Meretrix hornu, a form allied to, but not as produced
posteriorly as the Cytherea suberycinoides of the Paris basins.’’
Tritonium paucivaricatum is, according to Heilprin, a Cancellaria
which is ‘‘a form so closely related to C. evulsa of Brander from the
British Bartonian (upper Eocene), that it may well be doubted that
it is at all specifically distinect’’. Megistostoma striata, according to
Heilprin, exhibits no characters which will distinguish it from Bul-
laea expansa Dixon of the Eocene of Brackelsham, England, and the

Paris Basin.

Harris®® was the next investigator to compare representative spe-
cies of the West Coast and the East Coast Eocene. He says:

While comparing the Texas Eocene fossils with type specimens and
others in the collection of the U. S. National Museum and in the Phila-
delphia Academy of Natural Sciences, I have been impressed with the
remarkable sameness in the faunal characters throughout the vast extent
of the lower Claiborne or Lisbon horizon; many of the species from South
Carolina are identical with those from the banks of the Rio Grande, and
the rocks from Fort Tejon, California, furnish a very similar fauna
with several identical and many analogous species. Gabb’s Cardita hornii
is Venericardia planicosta Lam., as held by Conrad; the type specimen is
slightly malformed and imperfect but others from the same locality are
quite typical V. planicosta. Gabb’s Architectonica cognata is Conrad’s
Solarium alveatum; Gabb’s Architectonica hornii, Conrad’s Solarium
amoenium; Gabb’s Neverita secta, Conrad’s Natica aetites, and so on.
Gabb’s peculiar and characteristic little Whitneya ficus is known from
Alum Creek Bluff, Colorado River, Bastrop County, Texas and is in itself
a strong argument for the synchrony of the Texas and California beds
from which it is derived. Moreover in deposits of this horizon on both
sides of the Rockies there are similar developments in the genera Cras-
satella, Cytherea, Pyrula, Levifusus, Rimella, and others.

With the above facts in mind I can not help suggesting that those
who have: an opportunity to study the Hocene series of California (Tejon
deposits) would do well to look for the Midway stage which ranks
second in persistency among the subdivisions of the Eocene along the
Gulf Slope. In other words, search should be made along the Chico-
Tejon contact for such species as Hnclimatoceras ulricii, Cucullaea macro-
donta, Ostrea pulaskensis, together with varieties of Venericardia plani-
costa, Turritella mortoni, T. humerosa and other Midway forms.

88 Heilprin, A., Proc. Acad. Nat. Sci. Philadelphia, vol. 34, pp. 196-214,
1882.

89 Harris, Correlation of the Tejon with Eocene Stages of the Gulf
Slope, Science, vol. 22, p. 97, Aug. 18, 1893.

476 University of California Publications in Geology (Vou. 9]
From all evidence it seems likely that the Tejon series is the cor-
relative of the Claiborne at least in part.
All of these writers examined material which was principally
derived from the Tejon of Canada de las Uvas and hence their com-
parisons are chiefly valuable as respects the position of the Rimella

simplex Zone of California.

SPECIES COMMON TO THE GULF AND Paciric Provinces

The number of identical species between the Tejon Eocene and
the Hocene of the Gulf is much smaller than the writer first supposed.
Many of the forms which at first sight appear to be identical reveal
shght differences when directly compared. These differences are in
The general faunal
development in the Tejon is so similar to that of the Gulf Province

general of specific or subspecific value at least.

that one is easily deceived into thinking that the specific characters
are also alike.

A tabular comparison between identical or congeneric species of
the Gulf Province and the Tejon is given below.

Midway
Exilia pergracilis Conrad
Natica eminula Conrad

Protocardia nicolletti Conrad ef. Cardium marysvillensis
Natica perspecta Whitfield ef. Natica nuciformis

Lignitic

(Wilcox formation)

Philene alabamensis Aldrich = Megistostoma striata Gabb
Modiolus alabamensis Aldrich = Modiolus ornatus (Gabb)
Pleurotoma mediavia equiseta

Harris = Turris inconstans (Cooper)
Pleurotoma denticula Harris = Turris stocki, n.sp.
Cypraea smithi Aldrich = OC. mathewsonii Gabb
Natica eminula Conrad = Neverita secta Gabb
Calyptraea aperta Sol. — C. excentrica (Gabb)
Venericardia planicosta regia

Rogers = V. planicosta hornii Gabb
Venericardia planicosta var.

Harris = V. planicosta merriami Dick.
Ancillaria staminea Conrad ef. Olivula marysvillensis Dick.
Metula sylvaerupis Harris ef. M. harrisi, n.sp.
Ficopsis penita Conrad ef. EF. remondii (Gabb)
Pleurotoma roscoei Harris cf. Drillia cooperi, n.sp.

Cadulus abruptus Ald. and Meyer

Claiborne

Dentalium mississippiensis Con.

Oliva mississippiensis Conrad
Whitneya ficus Gabb

I

Tejon
Exilia dickersoni (Weaver)
Neverita secta Gabb

Cadulus pusillus (Gabb)
D. Stramineum Gabb
Olivella mathewsonii Gabb
Whitneya ficus Gabb

“]

1916] Dickerson: Tejon Eocene of California 47

Solarium alveatum Conrad ef. Architectonica cognata Gabb
Solarium amoenium Conrad Architectonica hornii Gabb
Trigonoarca decisa Conrad Arca hornii Gabb

Actaeon idoneus Conrad ef. A. moodyi, n. sp.

I

Dumble®’ found an interesting Eocene locality at Topila, Mexico,
Gulf Coast. At a depth of 1800 feet several shells were brought up in
the oil-drilling operations. Among them were the following Tejon
species: Orbitoides, sp., Neverita ef. secta Gabb, Dentalium strami-
neum Gabb, Conus remondw Gabb, Conus californiana (Conrad),
Turris monolifera (Cooper), Drillia, cf. ullreyana Cooper, and Turri-
tella ef. kewt, n. sp.

Unfortunately most of these similar or identical species are forms
with very great stratigraphic range in both the Tejon and the Gulf
Eocene. Natica, Modiolus, Cadulus, Calyptraea, Olivella, Olivula are
particularly poor genera for correlation purposes, as specific and
individual differences are not sharply marked and individual varia-
tion is great.

The occurrence of Whitneya ficus Gabb in lower Claiborne strata
of Texas, Solarium alveatum Conrad and Solarium amoenium Conrad
and a subspecies of Venericardia planicosta which is the equivalent of
V. planicosta hornw (Gabb) in the Claiborne of Alabama suggests that
the Rimella simplex zone, the fauna of the type Tejon, is the equiva-
lent of the Claiborne or lower Claiborne.

STAGES OF EVOLUTION OF THE SPECIES VENERICARDIA PLANICOSTA LAMARCK

The mutations of Venericardia planicosta Lamarck are very sug-
gestive. The important changes in this species, both on the Pacific
and Gulf Coasts, is a progressive alteration in the strength of radial
ribs and their interspaces and a similar acceleration of development.

V. planicosta venturaensis (Waring) is a higher form than
V. planicosta smithi (Aldrich) of the Midway stage but the inter-
spaces and ribs have the same relative width and development.

V. planicosta hornii Gabb which oceurs in the Turbinolia, Rim-
ella simplex and Balanophyllia zones of the Tejon group corre-
sponds in the lessening width of interspace with V. planicosta,
form a Harris’! of the lower Lignitic. V. planicosta merrianu
Dickerson of the Siphonalia sutterensis zone corresponds to V.

90 Dumble, E. T., Science, new series, vol. 35, pp. 906-908, 1912.
91 Harris, G. D., The Lignitic Stage, Bull. Amer. Pal., vol. 2, No. 9,

pp. 246-247, 1897.

478 University of California Publications in Geology (Vow. 9

planicosta, form y Harris of the upper Lignitie or lower Claiborne
stage both as regards growth stages and the mature forms.

GENERIC COMPARISON OF Mipway AND Trson FAuNAS

Harris lists the following genera from the Midway stage of the
Gulf Eocene :°?

Mipway GENERA Mar. Tej. Mipway GENERA Mar. Tej.
x Canicellaw= a Bn x
Scaphella 2.02... Ace an
x Volutay =... ae x
x Volutilithes 00000022... x
yo ae API x
x A of haeeieeer ee eer coe x
2 LUSUS) ie ee x x
x Strepsidura 20. X x
Gc ll ae aise eee eeeeeeee ee x x x a) oe ee ee x
Glycimeris x Ke IPYTODSIS) <ceccscceceecaessecceeeeeee
INGULG@ ay eeseeeeeccecseeeesncssseseeee= ore x Leucozonia —...00000000002 0222...
PA Gill a apse ener oa cesar rzeee x x IWIEW ANNU Soe coca
15,20 Ie eee eee RP eee x x Levifusus ........\00000004.2---- ee
Venericardia .........-.....--.-- x x Fulgur-Perissolax -........... x x
PN SUATLG moesvsseerccecemaeres ere x x Pseudoliva _..000222.2. 2... x
Crassatellites ~...2...::---..--- x Trop HON eee ee x x
ProtoCa nd aie seceence tee x Ms Murex cae x
CO) a1 9 0: eee peer ees erences — eats Triton x x
- x Pyrula (=Ficopsis) ...... x x
x x Calyptraphorus ............... aus ae
Mea aes tee x x Aporrhais 22222222. x
GOnD Ula ee eee x x Cerithiumi x? x
JEADK CHU 0 hy eee eee Pee x x GADD hex tec Le eo x x
Gastrochaema. 222-2... ee a3 Mesaliia 7.22... 5-seo tees a us
IME EIST a eer _ x Koel boas) eee x x
Wierticondital ses =-.ssee ee re ne DROS STO NOG ee ee mee a
Pholadomya ..........------------ x = Keilostoma .....................-. ates
Dentalium x x Calyptraea -...0.222.2. ..--- xX x
AGUS oe eco ee eec eee eececes ae x NEMO DNOMA ee ec. eeees se eeeeee x x
MTornatellaea wo -cece.ceeeceeee ene ae DONT cf: ae ee er pe x x
UAGY Shee eee eee ase = Amauropsis ...........---2-..--- me x
iy Lich ree eee x x SS Calla jieseeeeeeeee cores eee ee en x
Pleurotomella .........-........ 28 ae SOlarielila Meee ae eee x
SU CUI cyemeeneneeeneaeere ca eno eee me x Pleurotomaria(?) _........
Plewurotomiay es 2 eec-sessee x x Missumelilay See esess eeeeeeeeee ees x
Oliviellav 22. x x Enclimatoceras ........ Lae x< a.

Of these genera listed, Enclimatoceras is the one which disap-
peared at the end of Midway and also at the end of Martinez time.

92 Harris, G. D., Bulletin of American Palaeontology, vol. I, pp. 118-270,
1895-6.

1916] Dickerson: Tejon Eocene of California 479

Isocardia, Martesia, Cadulus, Caricella, Voluta, Volutilithes, Lyria,
Mitra, Exilia, Pseudoliva (?), and Scala (Epitonium) are Midway
genera which are represented in the Tejon but not present in the
Martinez. Most of these important genera are represented in the
Recent fauna of the tropics and hence the stage of evolution of the
Midway fauna is apparently nearer to the Recent than the Martinez
and, on the whole, is more closely related to the Tejon.

PROPOSED CORRELATION

Identical species, similar stages of generic evolution and the
mutations of Venericardia planicosta, all show a much stronger
relationship of the Tejon group to the three lower formations of the
Gulf Province, the Midway, Wilcox, and Claiborne, than was sus-
pected. Tejon time was long and was probably equivalent to
Midway (in part, at least), Wilcox, and Claiborne eons. The Jack-
son may be represented by the upper portion of the rhyolitic tufts,
the clay rock of Turner.

This study confirms and modifies somewhat the writer’s conclu-
sion ‘‘that the Martinez is not only equivalent to a portion of the
Midway, but represents a still earlier stage of the Eocene as well’’.
The generic relations between the Tejon and Midway are so close
that it seems probable that they are correlative at least in part.
Possibly the Martinez is the marine equivalent of the Puerco and
Torrejon of New Mexico, that is, Paleocene.

Pacific Province Gulf Province

Siphonalia sutterensis zone ) :
Ee ee eee ae vee ee eee eat Claiborne

Balanophyllia variabilis zone if

Tejon ‘Jai
Rimella simplex zone \Pawer ae

Sag Ow pared Fite gs ee Scene | Wilcox
Turbinolia zone...........- Se eee tee ete ay eRe ene ee: Midway
Solen stantoni zone ]
Martinez? Trochocyathus zitteli zone ecto seaeatncn Puerco and Torrejon(?)
Meretrix dalli zone 5

GENERAL CONCLUSIONS

(1) The Tejon group is both a stratigraphie and faunal unit
which is very distinct from the groups above and below.

(2) The Tejon group is unconformable upon the Martinez
Eocene and Chico-Cretaceous in the vicinity of Mount Diablo.
Unconformities are inferred in other areas as well.

480 University of California Publications in Geology (Vou. 9

(3) The Oligocene in the vicinity of Walnut Creek rests with
apparent unconformity upon the Tejon.

(4) The Ione formation of the Sierra Nevada is the uppermost
phase of the Tejon group.

(5) The deep gravels, bench gravels, the lower rhyolitic tuffs
and interrhyolitic stream gravels of the Sierra Nevada are the land
and stream-laid equivalents of the marine Ione Eocene, the upper-
most member of the Tejon group.

(6) Four faunal zones are recognized in the Tejon group, a
lowermost, the Turbinolia zone, then the Rimella simplex zone,
Balonophyllia zone and the Siphonalia sutterensis zone.

(7) The fauna of the Tejon group contains about 300 species.

(8) Only 25 species range downward into the underlying
Martinez Eocene and but 3 or 4 into the overlying Oligocene.

(9) The Tejon group is apparently the correlative of the Mid-
way (in part, at least), Wilcox (Lignitic) and Claiborne, Eocene
formations of the Gulf Coast Province.

1916] Dickerson: Tejon Eocene of California 481

DESCRIPTIONS OF NEW SPECIES

PELECYPODA

ACILA GABBIANA, n. sp.
Plate 36, figure 1

Shell small, oval with straight anterior dorsal margin which
slopes steeply to a sharp angle, the junction of broadly rounded
ventral margin; posterior dorsal margin gently convex; posterior
end, narrowly rounded; decoration consisting of delicate divaricate
sculpture crossed by incremental lines; lunule fairly definite;
escutcheon long and narrow.

This species differs from Nucula truncata, with which it has fre-
quently been confused, in the following repects: it is smaller, its
divaricate sculpture is more delicate, its escutcheon is more definite
and concentric sculpture is more regular.

Named in honor of Wilham Gabb, pioneer palacontologist of the
Pacifie Coast.

Dimensions.—Height, 6 mm.; length, 9 mm.

Occurrence.—The type was found at University of California
Locality 1817, lower Tejon beds, north of Coalinga. It has been
reported from many other Tejon localities, from the lowermost zone
of the Tejon to the uppermost. It may also occur in the Martinez
group as the form listed as Nucula ef. truncata Gabb may be this
species.

ARCA CLARKYI, n. sp.
Plate 37, figure 12

Shell small, subquadrate, with height almost equal to length;
beak inconspicuous, rounded, central; anterior margin nearly
straight, extending from a bluntly pointed end to a broadly rounded
ventral margin; posterior end broadly areuate; dorsal margin
straight; decoration consisting of acute ribs with interspaces about
twice their width.

The more quadrate shape of this species distinguishes it from
A. horniw Gabb.

Named for Dr. B. L. Clark.

Dimensions.—Length, 4 mm.; height, 3.5 mm.;

; convexity, 1.5 mm.

Occurrence.—University of California Locality 733.

482 University of California Publications in Geology Vou. 9

CRASSATELLITES LILLISI, n. sp.
Plate 36, figure 10

Shell solid, small, trigonal, with prominent, central beaks; the
anterior dorsal margin concave, sloping gently to a rounded anterior
end; the posterior dorsal margin straight and sloping to a narrowly
pointed posterior; ventral margin, broadly rounded; lunule large, but
obscure in type specimen; fine concentric, incremental lines decorat-
ing the shell.

Only the type specimen is known. It is easily distinguished
from C. grandis Gabb by its greater length and by the gentler
slopes of its dorsal margins.

Named in honor of Miss Helen Lillis, who donated much material
obtained from the type locality of this species.

Dimensions.—Height, 19 mm.; length, 26 mm.

Occurrence.—University of California Locality 1817, Fresno
County California, near base of the Tejon group.

CARDIUM MARYSVILLENSIS Dickerson
Cardium dalli Dickerson, Fauna of the Eocene at Marysville Buttes, Cali-
fornia, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 269, 1913.
A new name is necessary for this species, as Heilprin had pre-
viously named a Cardiwm in honor of W. H. Dall. Renamed for
its occurrence at Marysville Buttes, California.

GLYCIMERIS PERRINI, n. sp.
Plate 36, figures 6a, 6b, 6¢

Shell medium in size, nearly equilateral, cordate; beak small,
prominent, shghtly incurved, area very small; base broadly rounded ;
anterior end straight and slightly shorter than the posterior end.
The base is denticulated on interior. Shell is decorated by numerous
fine rounded radiating ribs which vary greatly in strength over
various portions of the shell. Some of the ribs are dichotomous.
Interspaces are very narrow. Concentric lines of growth cross
these ribs and on weathered specimens are very prominent.

This species resembles Glycimeris cor (Gabb) in outline but the
ribs are more numerous and the interspaces are not flat and wide as
in G. cor. Its more trigonal form is sufficient to distinguish it from
G. sagittatus (Gabb).

Named in honor of Professor James Perrin Smith of Stanford

University.

1916] Dickerson: Tejon Eocene of California 483

Dimensions.—Height, 12 mm.; length, 12 mm.
Occurrence.—University of California Locality 672.

GLYCIMERIS FRESNOENSIS, n. sp.
Plate 36, figure 7
Shell small, cordate, with beak decidedly twisted; anterior and
posterior dorsal margins nearly straight with steep slope to arcuate
ventral margin; decoration consisting of sharp dichotomous ribs.
This species is also found at the type locality of the Tejon.
7

Dimensions —Leneth, 7 mm.; height, 7 mm.

Occurrence.—University of California locality 1817.

GLYCIMERIS HANNIBALIT, n. sp.
Plate 36, figures 8a, 8b

Shell of moderate size, inflated, with broadly rounded ventral
margin and prominent beak. The anterior and posterior dorsal
margins are practically straight and parallel to the axis of the shell.
The anterior end is nearly straight except for a very slight central
concavity at the end of a broad umbonal groove. The posterior end
is broadly rounded with greatest areuity near the dorsal margin.
The decoration consists of about thirty flat radial ridges equal in
width to their interspaces. The interspaces are decorated by arrow-
like marks as in G. sagittata Gabb. Area long, narrow; interior of
ventral margin dentate.

This species is not orbicular like G. sagittatus Gabb but is more
quadrate than this form. It resembles @. veatchi var. major Stanton
but its height is less and it is more quadrate, its area is smaller
and narrower and the interspaces between ribs are wider. This
species grew considerably larger than the type, which is of medium
size.

Named for Harold Hannibal, whose collections of Tertiary fos-
sils have greatly aided the study of Tertiary palaeontology.

Dimensions.—Height, 20 mm.; length, 22 mm.

Occurrence.—University of California Locality 672 at the top of
the white sandstone member of the Tejon group north of Coalinga.

LEDA FRESNOENSIS, n. sp.
Plate 36, figures 2a, 2b

Shell long, rather robust for this genus; beak prominent and
situated two-fifths of the length from the anterior end. Anterior

484 University of Califorma Publications in Geology —{Vor. 9

dorsal margin straight with moderate slope; the posterior dorsal
margin slightly concave with a gentle slope to a narrowly rounded
rostrum; posterior end, narrowly rounded; ventral margin, broadly
convex. Very fine growth lines decorate the shell.

This species is larger, its rostrum is less pointed and its ribbing
much finer than L. gabbi Conrad.

Dimensions.—Height of broken specimen, the type, 13 mm.;
length, 22 mm.

Occurrence.—University of California Locality 1817.

LUCINA PACKI, n. sp.
Plate 36, figure 12

Shell small, subcircular in outline; posterior dorsal margin
straight with moderate slope to a subtruncate posterior; beak sub-
central, rounded, prominent; decoration consisting of very fine sharp
concentric lines of growth.

Named for Robert Pack, Palaeontologist, U. 8S. Geological Survey.

Dimensions.—Leneth, 8.5 mm.; height, 8 mm.

Occurrence.—Type is from University of California Locality 672.

LUCINA DIEGOENSIS, a. sp.
Plate 37, figures la, 1b

Shell medium in size, orbicular, thick, with central prominent
beaks. Lunule wide, short, and very prominent; escutcheon long, nar-
row; anterior dorsal margin markedly concave under the beaks; the
shghtly convex posterior dorsal margin slopes with moderate angle
to a truncated posterior end; ventral margin nearly semi-circular ;
right and left valves equal. The surface is marked by strong, sharp
concentric incremental lines and by a _ feebly developed umbonal
groove which extends to the middle of the posterior extremity.

This species is thicker than L. annulatus or L. acutilineatus and it
differs from both in the greater slope of its posterior dorsal margin.

Dimensions.—Height, 29 mm.; length, 32 mm.; thickness of two
valves, 16 mm.

Occurrence.—University of California Locality 2226, Tejon of
Rose Cafion, San Diego County, California.

MARCIA(?) CONRADI, n. sp.
Plate 38, figure 3
Shell small, ovate, thick, with thin shell substance; beak located
one-third the distance from anterior end, rounded and prominent;

1916] Dickerson: Tejon Eocene of California 485

ventral margin broadly arcuate; posterior end subtruncate, resembling
that of Marcia quadrata (Gabb) ; anterior end moderately convex ;
posterior dorsal margin slightly convex with gentle slope; anterior
dorsal margin slightly convex with moderate slope to the rounded
anterior end.

This species somewhat resembles Marcia quadrata (Gabb) but is
less elongate, its anterior end is more rounded and its posterior dorsal
slope is greater.

Named in honor of T. A. Conrad, the eminent palaeontologist who
first recognized Eocene strata on the Pacific Coast.

Dimensions.—Length, 18 mm.; height, 15 mm.; thickness, 5 mm.

Occurrence.—The type was found at University of California
Locality 1817, lower Tejon, northwest of Coalinga, California.

PHACOIDES (MYRTEA) TAFFANA, n. sp.
Plate 36, figure 11

Shell small, compact, trigonal ; beak small, prominent, opisthodetiec ;
concentric growth lines prominent, lamelliform. A marked posterior
fold extends from the beak to the posterior end; posterior dorsal
margin slightly convex; anterior dorsal margin slightly concave ;
base rounded. Area small and not distinetly set off. Pallial line
simple, entire; two cardinal teeth in right valve, the posterior one
being bifid; two cardinal teeth in left valve; a posterior lateral and
an anterior lateral tooth are found in the right valve with correspond-
ing sockets in the left valve.

Named in honor of Mr. J. A. Taff, Geologist, Southern Pacific
Company.

This species is easily distinguished from Diplodonta polita
(Gabb) by its lamelliform concentric ribs.
Dimensions —Height of a right valve, 5 mm.; length, 5.5 mm.
Occurrence.—University of California Locality 672.

SPISULA MERRIAMI Packard
Plate 39, figures 2a, 2b, 2¢
Shell small, trigonal, equivalve, nearly equilateral, slightly ven-
tricose, ornamented by numerous fine concentric ridges which are more
pronounced and less numerous on the anterior and posterior dorsal
areas than upon the other portions of the shell; beaks moderately
prominent, anterior dorsal area limited by a distinct ridge extending
from the umbo to the anterior extremity; the margin of this area is

486 University of California Publications in Geology [ Vor. 9

nearly straight; posterior dorsal slope slightly convex, lmited by an
indistinet ridge which extends from the beak to the base of the shell;
anterior extremity more sharply pointed than the posterior; base
very broadly rounded, hinge plate relatively broad, chondophore
oblique, shallow, apically roofed by a broad flat spur; left cardinal
prominent, high, arms broad, extending from the dorsal to the ventral
margin of the plate; ventral sinus narrow, flat; right cardinal with a
prominent anterior arm, and a well-developed, although relatively
thin posterior arm; laminae long, distant from the beaks; anterior
lateral formed from the margin of the plate, with top rounded, distant
from the anterior arm of the cardinal; posterior lateral also with
rounding top, dorsal and ventral slopes nearly equal; anterior ventral
lamina formed from the upturned edge of the hinge plate, and not
confluent with the anterior cardinal arm; anterior dorsals scarcely
developed, considerably smaller than the corresponding posterior one.
The general shape is quite uniform.

This trigonal species might be mistaken for S. ashburnert (Gabb).
It differs from that Cretaceous species in being less ventricose; in
having more pronounced concentric sculpture ; and in the possession of
a well-developed posterior cardinal arm.

Type described from Parson’s Peak, Fresno County, California,
University of California Locality No. 672.

Occurrence.—Kocene, Tejon group, Parson’s Peak, south side of
Mount Diablo, and Salt Creek, Fresno County, California (Dickerson).

Dimensions.—Lenegth, 18.6 mm.; height, 14.2 mm.; convexity, 4mm.

TIVELA PACKARDI, n. sp.
Plate 38, figures 2a, 2b

Shell small, trigonal in outline; base broadly rounded; beak small,
prominent; lunule inconspicuous and not definitely set off. The
slightly convex posterior dorsal margin is gentler than the anterior
dorsal margin. A rounded umbonal slope extends from the beak to a
point where the rounded base meets the slightly convex posterior end ;
anterior end sharply rounded. The shell is decorated by sharply
rounded lines of growth. These growth lines are few and larger upon
the posterior dorsal slope. The dentition is characteristic of the genus.

Named in honor of Dr. Earl Packard.

Dimensions.—Height, 10 mm.; length, 12 mm.

Occurrence.—University of California Locality 672.

1916] Dickerson: Tejon Eocene of California 487

TELLINA JOLLAENSIS, n. sp.
Plate 37, figure 3

Shell small, thin, with subcentral rounded beak; posterior dorsal
margin with moderate slope to a pointed posterior; anterior dorsal
margin with but a slight slope to a rounded anterior; ventral margin
very broadly rounded; decoration consisting of fine lines of growth
only.

Named for the occurrence of this species in the La Jolla Quad-
rangle, San Diego County, California.

Dimensions.—Length, 24 mm.; height, 14 mm.; thickness of two
valves, 5 mm.

Occurrence.—University of California Locality 2226.

GASTROPODA

ARCHITECTONICA ULLREYANA, n. sp.
Plate 40, figures 5a, 5b

Shell small, with five whorls coiled in a nearly flat spire. The
decoration on the upper surface of the whorls consists of eight to
twelve beaded threads. The upper surface of the body whorl is
slightly coneave and is decorated by about twelve beaded spiral
threads. The two threads near the suture are larger than all the rest
except the one on the periphery of the body-whorl forms a well-
marked keel. The base is decorated by about fifteen nodose spiral
threads similar to those upon the upper surface; a specially strong
one marks an angulation upon the body-whorl. Mouth, quadrangular.

The low spire of this species readily distinguishes it from A. hornw
Gabb and A. cognata Gabb. Its decoration resembles that of A.
tuberculata Weaver closely but it has a greater number of threads
upon the upper surface of the body whorl. They may be the same
species but only the cast of the upper surface of A. tuberculata ex-
ists. Their relations will remain indeterminate until better material
is found at the type locality of A. tuberculata, University of California
Locality 541.

Named in honor of Mr. Bert Ullrey of West Butte, California,
who assisted Mr. Watts in collecting at this locality.

Dimensions —Altitude, 2 mm.; maximum diameter, 5 mm.

Occurrence —University of California Loeality 1853.

488 University of Califorma Publications in Geology Vou. 9

ACTAEON MOODYI, n. sp.
Plate 38, figures 10a, 10b

Shell ovate; spire low, conical; whorls five and a half, the first
two being smooth nuclear. The shell is decorated by strong, evenly
spaced, equal spiral lines, four of which mark the third whorl, five
the fourth, and about eighteen the body-whorl. Whorls convex,
rounded; suture linear; mouth suboval; outer lp simple; columella
marked by the faint single plait of this genus.

Named in honor of Mr. Wilbur Moody, Field Geologist, Southern
Pacific Company.

This species is higher and less globose than A. lawsoni of the
Martinez group and its spire is less acute.

Dimensions.—Length, 9 mm.; width of body-whorl, 5 mm.

Occurrence.—University of California Locality 672.

ACMAEA RUCKMANI, n, sp.
Plate 39, figure 3

Shell small, low, nearly circular in outline; apex subcentral,
slightly eurving forward; surface decorated by about 25 thread-like
radiating ribs, with flat interspaces three times as wide as ribs. Three
or four concentric growth lines cross the radial ribs.

This species differs from A. teyonensis Gabb in its pronounced
radial decoration and in its nearly circular shape.

Named in honor of Mr. John Ruekman, who aided the writer in
collecting at the above locality.

Dimensions.—Length, 8 mm.; width, 7 mm.; height, 4 mm.

Occurrence.—University of California Locality 2225, south side
of Oroville South Table Mountain.

CHRYSODOMUS MARTINI Dickerson
Plate 39, figure 8

Phos(?) martini Dickerson, Fauna of the Eocene at Marysville Buttes,
California, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 288. 1913.

The type of the species described under the above name was defec-
tive. Better specimens of this same species were found at University
of California Locality 2225, south side of Oroville South Table Moun-
tain. They have moderately long, curved, slender canals and other
characters of the genus Chrysodomus.

1916] Dickerson: Tejon Eocene of California 489

CREPIDULA INORNATA, n. sp.
Plate 38, figures 5a, 5b

Shell subovate, smooth, number of whorls about two and a half;
spire twisted, suture obscure; deck about a third the length of shell;
margin of deck convex on outside and concave near inner edge.

This species has been figured as a ‘‘high’’ form of Galerus ex-
centricus Gabb but its deck is distinctive of the genus Crepidula.
G. excentricus Gabb occurs with it but interior is quite different.

This species differs from Crepidula (Spirocrypta) pileum Gabb in
that its spire is not immersed and the margin of its deck is not convex
in the center.

Dimensions.—Height above base, 4 mm.; length, 8 mm.

Occurrence.—University of California Locality 672.

CERITHIOPSIS DUMBLEI, n. sp.
Plate 38, figure 12

Shell elongate conical with nine whorls; the first two nuclear
whorls are smooth. The last seven are decorated by four spiral lines
of equal strength and equally spaced. Suture linear, impressed, the
space between two whorls being of the same width as that between
two of the spiral lines. Axial ribs, twelve to fourteen in number.
Occasionally these ribs are swollen to form slight varices. Base of
body-whorl is decorated by fine spiral threads only.

This species differs from C. alternata Gabb in that it lacks the
minor spiral threads. It differs from C. orovillensis Dickerson in its
greater length, in the regular spacing of its four spiral lines and its
lack of pronounced varices.

Named in honor of Professor E. T. Dumble, consulting geologist,
Southern Pacifie Company.

Dimensions.—Length, 9.5 mm.; width of body-whorl, 4 mm.

Occurrence.—University of California Locality 672.

CERITHIOPSIS OROVILLENSIS, n. sp.
Plate 39, figure 7

Shell medium in size for this genus, light-colored, conical. Nuclear
whorls decollated. A strongly channeled suture separates the post-
nuclear whorls. The fourth whorl is marked by three equidistant
spiral cords with interspaces equal in width to the cords. About
fourteen vertical axial ribs equal in strength to the cords also mark

490 University of Califorma Publications in Geology [ Vou. 9

this whorl. The junctions of the spiral cords form rounder tubercles
and spaces between appear to be round. The fifth, sixth, seventh and
eighth whorls are decorated by four spiral cords, the first of which is
slightly anterior to the summit; the second equal in size to first, and
separated from it by an interspace equal in width to the first cord.
These two cords occupy about the upper two-fifths of the whorl, while
the two lower and much stronger cords cover the rest of the whorl.
Vertical axial ribs slightly weaker than the spiral cords also mark
these whorls. The nodes made by the crossing of the two sets of
lines are elongated from left to right. This is most marked in the
two posterior ribs. In addition to these decorations swollen varices
occur upon the whorls at irregular intervals. These varices are very
strongly marked by the spiral cords, the axial ribs being very weak.
Of the axial ribs fifteen occur upon the fifth, sixteen upon the sixth,
twenty upon the seventh and eighth. The ninth, or body-whorl, is
similarly decorated. Its base is marked by two strong spiral keels,
the first of which is nodose, and by six or seven spiral lines. Aperture
roughly oval; columella twisted and covered by a thin eallus.

This species is much smaller than either C. excelsa Dall or C. alter-
nata Gabb. Its well-marked varices and the lesser number of spiral
cords distinguish it at once from C. excelsa. It is broadly conic while
C. alternata is elongate conic. C. orovillensis n. sp. has two sets of
spiral cords, an upper and weaker and a lower and stronger, while the
weaker and stronger cords of C. alternata, as the name suggests,
alternate.

Dimensions —Length, 6 mm.; diameter, 2 mm.

Occurrence.—University of California Locality 2225, south side of
Oroville South Table Mountain.

DRILLIA OROVILLENSIS, n. sp.
Plate 41, figure 4

Shell slender, fusiform, with spire acutely pointed; whorls eight,
of which two nuclear are smooth; last whorl three-fifths of the length
of the shell. The transverse sculpture consists of twelve sharply
elevated flexuous ribs with interspaces twice their width and fine
threads parallel to ribs in the interspaces. These ribs are largest at the
shoulder, which is located at the middle of a spire-whorl. Five spiral
lines cross the ribs and one larger than the rest is found at the angle.
The flexuous transverse ribs on the body-whorl extend from the linear

1916] Dickerson: Tejon Eocene of California 491

suture over three-fourths of its length. The sinus is shallow and
slightly above the shoulder. Aperture elongate-oval; canal long,
slender, straight.

This species differs from D. ullreyana Cooper in its greater
length, in its more elongate and less nodose, transverse ribs which are
more numerous than those of D. ullreyana.

Dimensions.—Lenegth, 7.5 mm.; diameter, 2.5 mm.

Occurrence.—University of California Locality 2225, south side of
Oroville South Table Mountain, Butte County, California.

DRILLIA COOPERI, n. sp.
Plate 40, figures 6a, 6b

Shell spindle-shaped with ten slightly convex whorls; the first two
nuclear whorls are smooth and slightly more convex than the rest.
The third and fourth whorls have a slight angulation just above a
linear impressed suture. The last eight whorls are decorated by five
spiral threads or bands crossed by growth lines characteristic of this
genus. The band just below the suture is flat and slightly wider than
the next three. The three or four threads below the suture on
the last five whorls are stronger than the rest. The body-whorl and
canal are together nearly twice as long as the spire. The mouth is
oval and narrows gradually into a long nearly straight canal; outer
lp smooth; inner lip with a very slight callus.

This species can be readily distinguished from the other west coast
Eocene forms of the genus Drillia by its nearly smooth whorls.

Named in honor of Dr. J. G. Cooper, who first described species
from this vicinity.

Dimensions —Length of broken specimen, 20 mm.; length of spire,
9 mm.; width of body-whorl, 8 mm.

Occurrence.—University of California Localities 785, 1853; type
specimen from latter locality.

EPITONIUM TEJONENSIS, n. sp.
Plate 38, figure 4

Shell elongate, only moderately slender, whorls nine, the first
two being smooth; mouth round; whorls convex and decorated by
spiral lines and by varices, the latter being the more pronounced. The
body-whorl has about twenty-five varices which run almost to the
linear suture. These varices are slightly swollen in the middle of

492 University of Califorma Publications in Geology [Vor. 9

each whorl. About ten faint spiral threads cross the varices, forming
slight nodes at their intersection. A strong spiral cord ridges the
base of the body-whorl. The body-whorl is much expanded in com-
parison with the spire whorls. The spire whorls are decorated in a
similar fashion to the body-whorl. The varices, however, are less
numerous on the upper whorls.

This is the first time that this genus has been reported from the
Eocene of the Pacific Slope. <A cast of what appears to be this same
species was found in the Eocene of the Marysville Buttes.

Dimensions.—Length, 13 mm.; width of body-whorl, 5.5 mm.

Occurrence.—University of California Locality 672.

GALEODEA SUTTERENSIS, n. sp.
Plate 40, figures 1 and 2

Shell large, solid with great body-whorl and short spire; whorls
seven, tabulate; spire whorls exhibiting a well-marked nearly square
shoulder which is nodose at the crossing of the fine, sinuous growth
lines and the strong spiral line marking the shoulder; fine spiral lines
subequal in strength decorationg whorls; body-whorl at shoulder
marked by about fourteen sharp, elongate spinous nodes; one or two
rows of nodes decorating body-whorl in addition to shoulder nodes;
mouth oval; outer lip thickened; inner lip heavily incrusted; canal
long and twisted.

This species differs from G. tuberculata (Gabb) in its more spinous
nodes and in its much longer canal.

Dimensions.—Length, 35 mm.; width of body-whorl, 27 mm.

Occurrence.—University of California Locality 1853.

FICOPSIS COOPERII Gabb
Plate 37, figure 7

Gabb’s type was a much eroded specimen obtained from the Tejon
of Rose Cafion, San Diego County, California. The specimen figured
in this paper shows three rows of sharply pointed nodes instead of
rounded ones on the body-whorl. The shoulder is markedly square
in contrast to Gabb’s figure, in which there is a marked slope from
suture to second row of nodes on the body-whorl. As Gabb predicted,
the shell is ornamented by very fine spiral lines. Mouth has three
marked angulations on outer lip. This species is easily distinguished
from Ficopsis cowlitzensis Weaver by its larger nodes and by the

1916] Dickerson: Tejon Eocene of Califorma 493

irregular distribution of the nodes and by the smaller number of
of nodes.

The figured specimen was obtained from the type locality in Rose
Cafion, University of California Locality 2226.

FASCIOLARIA BILINEATA, n. sp.
Plate 37, figures 6a, 6b

Shell fusiform with moderately long, narrow canal; seven or eight
whorls. The first three nuclear whorls, smooth. The last four or
five whorls are decorated by two very strong spiral lines, the upper
one of which marks a very prominent shoulder on the whorls of
mature specimens. These spiral lines are crossed by eight to ten axial
ribs which extend from suture to suture. The space between the wavy
suture and the shoulder is covered by fine spiral threads; outer lip
erenulate ; inner lip with three oblique plaits.

The younger specimens do not show the shouldering on the whorls
but have rounded whorls instead. The number of whorls was ob-
tained from a study of a young specimen.

Dimensions —Height of broken type, 15 mm.; width of body-
whorl, 9 mm.

Occurrence.—The type specimen was obtained from the Tejon of
Rose Cafion, San Diego County, California, University of California
Locality 2226.

FUSINUS MERRIAMI, n. sp.
Plate 40, figures 2a, 2b

Shell with long, acuminate spire and with long, straight, narrow
canal; whorls, eleven in number; the first two rounded; the other
whorls are angulated at a point about two-thirds of a whorl-length
below the suture. The last nine whorls have the angle marked by
ten flat pointed nodes which are decidedly upturned on the body-
whorl. The space above the angle of a whorl is decorated by seven
to ten spiral lines and by five growth lines of about the same strength.
Below the angle are found three or four spiral lines which alternate in
size. The decoration on the body-whorl is similar to that of the spire-
whorls. The spiral lines below the angle on the body-whorl are eight
in number.

Named in honor of Professor J. C. Merriam, whose kindly criticism
has been of great service in the preparation of this paper.

494 University of California Publications in Geology [Vou. 9

Dimensions.—Length of nearly perfect specimen, 24 mm.; width of
body-whorl, 7 mm.; length of spire, 10 mm.
Occurrence.—University of California Locality 1853.

MONODONTA WATTSI, n. sp.
Plate 40, figures 3a, 3b

Turbinate, with five convex whorls; the first two are smooth; the
remaining whorls are decorated by slightly nodose spiral lines. A
fairly well developed collar with spiral threads upon it is found on
the body-whorl just below the linear suture. The threads upon this
collar and upon the base are finer than those of the central portion
of the whorls. Outer lip simple; inner lip thinly callused; a single
tooth characteristic of the genus is found upon the columella.

This species is also found in the Tejon at California Academy of
Sciences Locality 240, near Vader, Washington.

Named in honor of Mr. W. L. Watts who first collected at this
locality.

Dimensions.—Leneth, 6 mm.; width of body whorl, 7 mm.

Occurrence.—University of California Locality 1853.

METULA HARRISI, n. sp.
Plate 42, figure 1

Shell elongate fusiform, with spire about as long as the body-
whorl. Whorls are seven or eight in number, the two upper ones
being lost. The last three whorls are cancellated by one or two long,
rounded varices. The body-whorl and the two preceding whorls are
decorated by axial ribs and spiral lines of equal strength, giving the
shell a reticulated appearance. Outer lip thickened ; inner lip covered
by a thin, lone callus; canal short, shehtly twisted.

This form is very similar to M. sylvaerupis Harris of the Lignitic
Stage of the Gulf Coast Eocene. It appears to differ from WM.
sylvaerupis in its lack of ‘‘one or two comparatively large spiral lines
on the humeral slope.’’

Named in honor of Professor G. D. Harris of Cornell University,
whose standard works on the Hocene of the Gulf Coast have been of
ereat service to the writer.

Dimensions.—Length of broken specimen, 17 mm.; width of body-
whorl, 6 mm.

Occurrence —University of California Locality 1817.

1916] Dickerson: Tejon Eocene of California ; 495

MITRAMORPHA PARSONSI, n. sp.
Plate 38, figure 11

Shell fusiform, with spire almost as long as body-whorl; whorls
eight, the first three being smooth; the other whorls strongly
eancellated by rounded elongated varices. Eight varices are found
on fourth whorl, seven on the fifth, six on the sixth and seventh, and
four on the body-whorl. The spire-whorls except the first three are
distinctly shouldered about a third of the distance below the sinuous,
linear suture. The space between the apex and shoulder of these
whorls is covered by two or three small spiral threads, while the space
below the shoulder is decorated by two to four spiral lines with
interealary threads. These spiral lines number about twenty on the
body-whorl. Mouth elongate-oval; outer lip thickened; inner lip
marked by six plaits, the uppermost being the strongest.

Named in honor of Mr. Benjamin Parsons, some time field geolo-
gist, Southern Pacific Company.

Dimensions.—Length, 12 mm.; width of body-whorl, 4.5 mm.

Occurrence.—University of California Locality 672.

MUREX (OCINEBRA) NASHI, n. sp.
Plate 41, figures 7a, 7b

Shell short, with small spire and large body-whorl; nucleus small,
smooth, of three whorls; remaining four whorls decorated by very
prominent sculpture, consisting of twelve to fourteen equally spaced,
thick lamelliform varices, which are thick, sharp and spinose at the
intersection of the spiral ribs, especially prominent at the shoulder;
spiral sculpture of spire consists of four rounded cords between suture
and shoulder; shoulder is marked by a larger spiral cord, below which
are two or three more spiral cords similar to the ones above the
shoulder ; interspaces linear. Al! the cords tend to form spines upon
crossing the varices. The body-whorl is similarly decorated except
that there are four major spiral cords below the shoulder, the upper
two being most prominent. Two minor cords are found between the
major. Aperture ovate; canal short, wide and recurved; outer lip
with five or six coarse lirae within; inner lip covered by a thin colu-
mellar fold.

Named in honor of Mrs. Louise Nash, whose excellent drawings
have aided work in palaeontology.

Dimensions.—Leneth, 12 mm.; diameter, 8 mm.

496 University of California Publications in Geology [Vor. 9

Occurrence.—University of California Locality 2225, Oroville
South Table Mountain, Butte County, California.

NATICA GESTERI, n. sp.
Plate 38, figure 6

Shell small, high, with five whorls. The spire, one-fourth the shell-
length, has slightly convex, smooth whorls. The body-whorl which is
unusually elongate for this genus is gently convex. Aperture
semilunar; outer lp simple; inner lip incrusted; umbilicus small,
narrow, resembling that of Lunatia hornia Gabb.

The greater length of this species distinguishes it from other
naticoid forms of the Tejon.

Named for Mr. Clarke Gester who discovered this species.

Dimensions—Length, 15 mm.; width of body-whorl, 9 mm.

Occurrence.—University of California Locality 1817.

NYCTILOCHUS THUNANI, n. sp.
Plate 41, figures 8a, 8b

Shell fusiform, with moderately high spire; whorls seven, the first
two whorls being smooth; third whorl decorated with ten swollen
nodes which extend from suture to suture; fourth, fifth, sixth and
seventh whorls are decorated by similar elongate nodes which become
decidedly sinuous upon the body-whorl; suture sinuous, distinct ;
body-whorl has a wide mouth which is narrowed in advance; canal
recurved, twisted; outer lip thickened and denticulated on interior ;
inner lip covered by a slight callus. Numerous well-marked revolving
lines which alternate regularly in size, cover all the last five whorls;
these lines are crossed by finer axial lines which vary but slightly.

This species resembled Nyctilochus whitney: (Gabb), but its spire
is shorter, mouth wider, body-whorl stouter and the spiral lines al-
ternate regularly in size. There are occasionally as many as four
minor spiral lines between major spiral lines on N. whitneyi and the
major ones are more strongly set off than in N. thunane.

Named in honor of Mrs. Fred Thunan of Oroville, who presented
the type to the University of California. :

Dimensions.—Height, 19 mm.; width of body-whorl, 12 mm.

Occurrence.—University of California Locality 2225, about one
mile north and three degrees west of Butte County Hospital, Tejon of
Oroville South Table Mountain.

1916] Dickerson: Tejon Eocene of California 497

NYCTILOCHUS DIEGOENSIS (Gabb)
Plate 41, figures 6a, 6b

Tritonium diegoensis Gabb, Geological Survey of California, Palaeon-
tology, vol. 1, p. 95, 1864.

This species oceurs in the Tejon of Oroville South Table Mountain.
Several specimens exhibit the aperture and the canal far better that
Gabb’s type. The canal is very short and narrow and the outer lip
is thickened and denticulated. In the type the canal and aperture
are obscured by the rock matrix.

PERISSOLAX GABBI, n. sp.
Plate 37, figure 14

Shell thick, spire moderately high (?), body-whorl prodoundly
angulated at a point one-third of its length from the posterior ; suture
distinct ; portion of whorl above shoulder slightly convex and nearly
at right angles to the axis; body-whorl decorated by very prominent
axial ribs which extend from the suture over the entire whorl. These
ribs have flat-pointed nodes at the shoulder and are nearly obsolete at
either end. Revolving lines of moderate size with minute interlacing
riblets cover the entire shell. These lines are crossed by fine growth lines
which give portions of the surface a reticulated appearance. Four or
five of these revolving lines are found above the shoulder of the body-
whorl. Mouth quadrate; outer lip simple and divided in thirds by
two angulations; inner lip shehtly inerusted; canal long and nearly
straight.

It appears to be a descendant of Parissolax brevirostris Gabb of
the Chico (Cretaceous), to which it bears a striking resemblance.
P. brevirostris has three distinct angulations on outer lp and a
rounded body-whorl, while P. gabbi has only two angulations on outer
lip and a decidedly angular body-whorl. P. gabbi is also less robust.
The genus Perissolax resembles Tudicla of the eastern Eocene in gen-
eral appearance. They both appear to belong to the Fulguridae
rather than to the Fusidae as Gabb suggested.

Named in honor of W. M. Gabb, who laid the foundation of
palaeontology on the Pacifie Coast.

Dimensions.—Lenegth of broken specimen, 25 mm.; width of body-
whorl, 14 mm.

Occurrence.—The specimen figured was found at University of
California Locality 532, Solen Stantoni Zone, where it was asso-
ciated with Solen stantont Weaver and Thracia karquinesensis Weaver.

498 University of Califorma Publications in Geology _—‘[Vou. 9

ODOSTOMIA PACKI, n. sp.
Plate 37, figure 11

Shell small, elongate, slender, with at least twelve whorls; spire
high with acute apex; whorls flat-sided, smooth or ornamented by
very fine spiral threads, suture distinct, linear, channeled; aperture
round; outer lip marked by an internal spiral rib; inner lip by two
plaits, which are characteristic of this genus.

Named in honor of Robert W. Pack, Palaeontologist, U. S. Geolog-
ical Survey.

Dimensions—Lenegeth of broken type, 10 mm.; width of body-
whorl, 3.5 mm.

Occurrence.—The type is from University of California Locality
2226, Rose Canon, San Diego County, California. This species also
occurs at University of California Locality 1817, lower Tejon beds
north of Coalinga, California and at California Academy of Sciences
Locality 183, Vader, Lewis County, Washington, in the west bank of
the Cowlitz River about one and three-fourths miles southeast of
Vader or about one-half mile south of Locality 182.

STREPSIDURA HOWARDI, n. sp.
Plate 37, figure 13

Shell robust, medium in size, with twelve prominent, rounded
nodes ; number of whorls unknown; suture wavy ; body-whorl swollen ;
strong spiral lines about twenty in number decorating the body-
whorl; mouth semi-oval; outer lip thin; inner lip but slightly in-
erusted.

Dimensions —Leneth of broken type, 27 mm.; width of body-
whorl, 23 mm.

Occurrence.—University of California Locality 476.

SIPHONALIA SUTTERENSIS Dickerson
Plate 41, figures 5a, 5b, 5c, 5d, 5e

Siphonalia sutterensis Dickerson, “Fauna of Eocene at Marysville Buttes,
California,’ Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 2838, 1918.

A large series of specimens of this species were collected at Uni-
versity of California Locality 2225. The younger specimens are
slenderer than the mature forms, the canal is less bent, the spiral
ribbing on the body whorl is more conspicuous, and nodes of the body
whorl are less marked. A young specimen resembles a form belonging

to the genus Nyctilochus.

1916] Dickerson: Tejon Eocene of California 499

SURCULA CLARKI Dickerson
Plate 41, figures la, 1b

Surcula clarki Dickerson, “Fauna of the Eocene at Marysville Buttes,
California,” Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 278, 19138.

A series of specimens found in the Tejon of Oroville South Table
Mountain shows a variation in form as the above-mentioned species
grows in size. The shouldering of the large specimens is far more
prominent than in the type and the surface between the shoulder and
suture of the larger whorls is distinctly concave.

SURCULA GESTERI, n. sp.
Plate 42, figure 4

Shell spindle-shaped with eight whorls; the three nuclear whorls
the smooth; the other whorls of the spire are decorated by two
rows of rounded nodes made by the crossing of about sixteen axial
ribs and two strong spiral lines. The upper row of nodes is slightly
larger and they mark the shoulder of the whorl. The space between
the shoulder and the appressed suture is concave and marked only
by spiral lines. The body-whorl has a similar set of axial ribs
crossed by six subequal spiral lines in its upper half and by about
six spiral threads which alternate in size on its lower half. Sinuous
erowth lines characteristic of this genus mark the space above the
shoulder. The sinus is also found on the thin outer lip of some
specimens. Mouth elongate-oval; inner lip shghtly incrusted.

Its double row of rounded nodes will serve to distinguish it at
once from other members of this genus which have thus far been
described from the Tejon group. The older specimens are some-
what more elongate than younger ones and body whorl is not so
wide.

Named in honor of Mr. Clarke Gester.

Dimensions—Length, 9 mm.; width of body-whorl, 3 mm.

Occurrence.—This species was found at University of California
Locality 672.

TURRIS STOCKI, n. sp.
Plate 42, figure 5

Shell spindle-shaped with nine or ten whorls; the first two or
three whorls of the type specimen are missing. The spire-whorls
are decorated by a nodose spiral line in the center of each whorl.
Separated from this central line by a wide space are two closely

500 Unversity of California Publications in Geology [VoL. 9
set spiral lines, both above and below, adjacent to the linear im-
pressed suture. The decoration of the body-whorl consists of a
nodose spiral line at the shoulder; twelve to fifteen spiral lines are
found below the shoulder, minor threads occurring between these
lines.

This species is distinguished from 7. monolifera (Cooper) by
its greater number of nodes and by greater spire length.

Named in honor of Mr. Chester Stock, graduate student, Uni-
versity of California.

Dimensions.—Length, 14 mm.; width of body-whorl, 4.5 mm.

Occurrence.—University of California Locality 672.

TURRITELLA BUWALDANA, n. sp.
Plate 42, figures 7a, 7b

Shell slender, elongate; whorls fourteen or fifteen; each flat-sided
whorl carinated near base, diminishing in diameter toward the apex.
Sculpture consists of two small spiral threads just above a linear
suture, then four strong spiral lines with an intercalary thread
and two threads close together on apex. The differences in these
lines are more emphasized in the younger specimens and in the
lower whorls of older specimens. The two small threads just above
and the two just below the suture of the last whorls of a large speci-
men are absent, the intercalary threads are much stronger than in
the upper whorls and the four principal ribs are practically equal
in strength. Spiral lines alternating in size decorate the base of
the body-whorl. Sinuous lines of growth cross the spiral lines.

This species has a flat-sided whorl while 7. wvasana Conrad has
a convex whorl. The major spiral ribs of 7. weasana Conrad are
equally accentuated and evenly spaced while on 7. buwaldana, n.
sp. they vary in strength.

The younger whorls of this species resemble those of 7. mer-
riami Dickerson closely but the development of the later whorls in
the two cases is opposite. The principal carina on 7’. merriami be-
comes more and more pronounced while the reverse is true with the
species described above. This species has also been found at the
type locality of the Tejon group on the Canada de las Uvas. It is
very close to a Turritella described by Arnold as Turritella mar-
tinezensis (?) var. lompocensis. This form is really a species and
not a variety. The principal differences appear to be as follows:
T. lompocensis has a slightly concave whorl while 7. bwwaldana is

1916] Dickerson: Tejon Eocene of California 501

flat; the lower carina becomes more prominent on 7. lompocensis on
the later whorls whereas the reverse is true on the other; the two
sets of spiral threads on either side of the suture appear to be
absent on 7’. lompocensts.

Named in honor of Dr. John P. Buwalda.

Dimensions :—Length of medium-sized specimen, 20 mm.; di-
ameter, 6 mm.

Occurrence :—University of California Locality 672 in white sand-
stone of the Tejon group just beneath the overlying diatomaceous
shale.

TURRITELLA KEWI, n. sp.
Plate 42, figure 8

Shell long, slender; whorls probably about thirteen or fourteen
in number; each flat-sided whorl is decorated by five spiral lines
with a single fine thread in the interspace. The spiral lines consist
of two sets, an upper one near the suture of three closely set lines
and a lower of two lines which are relatively widely separated. The
suture linear, impressed, slightly below the surface of the flat-sided
whorls. Mouth, quadrate.

This species is distinguished from 7. buwaldana, n. sp. by a dif-
ferent suture, by a great apical angle and by its decoration. — It
oceurs with 7. wvasana and with 7. buwaldana at University of
California Locality 672.

Named in honor of Mr. Wiliam Kew.

Occurrence:—University of California Locality 672, Tejon of
Fresno County, California.

Dimensions:—Length of broken type, 22 mm.; width of body-
whorl, 8 mm.

TURRITELLA ANDERSONI, n. sp.
Plate 42, figures 9a, 9b

Shell very elongate with about sixteen whorls which increase
but slightly in size. The sides of the whorls are flat and in the
type are decorated by minute obscure spiral threads crossed by
small sinous growth lines. Suture impressed, linear.

This species differs from 7. wvasana Conrad in shape of whorls,
in lack of strongly marked ribbing and in having a smaller apical
angle.

It differs from 7. pachecoensis Stanton with which it has been

502 University of California Publications in Geology (VoL. 9

confused in the following respects: its apical angle is smaller; its
whorls are flat and not angulated distinctly near the suture and
it is smaller.

It may be identical with 7. conica Weaver but the type of this
last species is such a poor one that this point can not be decided.

A spirally ribbed form which is apparently an individual varia-
tion is found associated with the typical form described above. This
form is also figured. (See figure 9b.)

Named in honor of Mr. F. M. Anderson, curator of the Depart-
ment of Palaeontology, California Academy of Sciences, who first
studied the fauna from the type locality of this species.

Dimensions:—Length of broken type, 28 mm.; width of last
whorl on type, 8 mm.

Occurrence:—The type specimen was obtained from University
of California Locality 1817, lower Tejon of Fresno County, where
it is very abundant. Collectors, Clarke Gester and R. HE. Dickerson.
It is also found at University of California Locality 1428, which
is about fifteen hundred feet above the base of the Tejon south of
Mount Diablo.

TURRITELLA LAWSONI, n. sp.
Plate 42, figure 10

Shell elongate conic; number of whorls unknown; suture linear,
impressed; whorl slightly concave with center of coneavity below
middle; lower fourth of whorl flat with surface parallel to axis;
base of whorl, nearly flat, overhanging succeeding whorl, making an
acute angle with axis of shell; decoration consisting of numerous
fine threads of variable strength.

Dimensions :—Height, 36 mm.

Occurrence:—Tejon group. Section 24, Domengine Ranch. Coll.
F. M. Anderson, University of California Locality 2295.

XENOPHORA STOCKI, n. sp.
Plate 37, figures 4a, 4b

Shell, low trochiform with six whorls; shell substance thin.
Whorls are medially shouldered, with steep slope from a wavy, linear
suture to the shoulder. The space between the shoulder and the next
whorl is parallel to the axis of the shell. This space is further dec-
orated by about seven roughened nodes whose apices are at the
shoulder. The shell surface is pitted in several places. These round

1916] Dickerson: Tejon Eocene of California 503

pits were once occupied by pebbles which the animal had agelutinized
to its shell. Only the type specimen and a fragment are known.

Named for Mr. Chester Stock who has assisted the writer on
numerous occasions and who collected the type from the Tejon of
Rose Canon.

Dimensions:—Height of broken type, 18 mm.; width of body
whorl, 30 mm.

Occurrence:—University of California Locality 2226, Tejon
group, Rose Canon, San Diego County, California.

EXPLANATION OF PLATE 36

Fig. 1. Acila gabbiana, n. sp., * 3.

Fig. 2a. Leda fresnoensis, n. sp. * 1. Left valve of type.

Fig. 2b. Leda fresnoensis, n. sp., *X 1. View showing anterior end of
right valve of a cotype.

Fig. 3. Leda gabbi Conrad, « 2. U. C. Locality 672.

Fig. 4. Arca hornii Gabb, * 2. U. C. Locality 672.

Fig. 5a. Glycimeris sagittatus Gabb, &« 2. U. C. Locality 672.

Fig. 5b. Glycimeris sagittatus Gabb, « 2. View showing hinge.

Fig. 6a. Glycimeris perrini, n. sp., * 2. Type.

Fig. 6b. Glycimeris perrini, n. sp., * 2. Hinge view of type.

Fig. 6c. Glycimeris perrini, n. sp., * 2. Young specimen, a cotype.

Fig. 7. Glycimeris fresnoensis, n. sp., * 3. Type.

Fig. 8a. Glycimeris hannibali, n. sp., * 2. Type.

Fig 8b. Glycimeris hannibali, n. sp., * 2. Hinge view of type.

Fig. 9a. Crassatellites mathewsonii (Gabb), * 2. U. C. Locality 672.

Fig. 9b. Crassatellites mathewsonii (Gabb), * 2. 3

Fig. 10. Crassatellites lillisi, n. sp., * 1.

Fig. 11. Lucina (Myrtea) taffana, n. sp., * 3.

Fig. 12. Lucina packi, n. sp., * 2.

[504]

UNIVE <CAEIF, (PUBL, BULL. DEPT. GEOL. [DICKERSON] VOL. 9, PL. 36

EXPLANATION OF PLATE 37

Fig. la. Lucina diegoensis, n. sp., « 1.

Fig. 1b. Lucina diegoensis, n. sp., * 1. Umbone view.

Fig. 2a. Venus aequilateralis Gabb, « 2,

Fig. 2b. Venus aequilateralis Gabb, * 2. Umbone view.

Fig. 3. Tellina jollaénsis, n, sp., * 1.

Fig. 4a. Xenophora stocki, n. sp., *« 1. Top view of type.

Fig. 4b. Xenophora stocki, n. sp., * 1. Side view.

Fig. 5a. Spiroglyphus(?) tejonensis Arnold, * 38. Bottom view.

Fig. 5b. Spiroglyphus(?) tejonensis Arnold, « 2. Top view.

Vig. 6a. Fasciolaria bilineata, n. sp., * 8. Back view of type specimen.

Fig. 6b. Fasciolaria bilineata, n. sp., * 38. Aperture view of cotype.

Fig 7. Ficopsis cooperii Gabb, * 2. Aperture view of a cotype, a much
better preserved specimen than Gabb’s type.

Fig. 8. Turris fresnoensis Arnold, « 3. This specimen shows the form
of canal better than Arnold’s type.

Fig. 9. Sureula supraplanis (Cooper), * 1. Back view of a cotype.
This species was placed in the genus Fusus by Cooper. Better preserved spe-
cimens show the sinus of the genus Surcula.

Fig. 10. Architectonica, sp.,< 3. The figured specimen was found at
University of California Locality 694.

Fig. 11. Odostomia packi, n. sp., * 3. Type specimen,

Fig, 12. Arca clarki, n. sp., < 3.

Fig. 13. Strepsidura howardi, n. sp., * 1.

Fig. 14. Perissolax gabbi, n. sp., * 1.

[506]

UINIVGRGALIF. PUBL, BUEE, DEPT. (GEOL. [DICKERSON VOEn So, Pi. or

EXPLANATION OF PLATE 38

Fig. la. Meretrix hornii Gabb, * 2.

Fig. 1b. Meretrix hornii Gabb, * 2. Showing hinge. U. C. Locality 672.

Fig. 2a. Tivela packardi, n. sp., * 2.

Fig. 2b. Tivela packardi, n. sp., * 2. View showing hinge. Cotype from
U. C. Locality 672.

Fig. 3. Marcia (?) conradi, n. sp., * 2. Type specimen.

Fig. 4. Mpitonium tejonensis, n. sp., * 2. Type.

Fig. 5a. Crepidula inornata, n. sp., * 3.

Fig. 5b. Crepidula inornata, n. sp., * 3. View showing deck.

Fig. 6. Natica gesteri, n. sp., « 2.

Fig. 7. Amauropsis alveata (Conrad), & 2. The young individual
figured shows the fine spiral threads plainly. The umbilical chink is not
so prominent in older individuals. U. C. Locality 672.

Fig. 8. Natica uwvasana Gabb, *« 1.

Fig. 9a. Natica hannibali Dickerson, * 1. This large specimen shows
the peculiar callus on the inner lip better than the type. Specimen is from
the Tejon group near Domengine Creek, Fresno County, Cal.

Fig. 9b. Natica hannibali Dickerson, * 1. Back view of same specimen.

Fig. 10a. Actaeon moodyi, n. sp., * 2. Aperture view of type. U. C.
Locality 672. This form is also found at the type locality of the Tejon group.

Fig. 10b. Actaeon moodyi, n. sp., * 2. Back view of type.

Fig. 11. Mitramorpha parsoni, n. sp., X 2. Type specimen from U. C.
Locality 672.

Fig. 12. Cerithiopsis dumblei, n. sp., * 3.

[508]

UNIV. CALIF, PUBL. BULL. DEPT. GEOL. [DICKERSON] VOL. 9, PL. 38

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EXPLANATION OF PLATE 39

Fig. 1. Ostrea cf. appressa Gabb, X 2. From Tejon of Oroville South Table
Mountain, U. C. Locality 2225,

Fig. 2a, 2b, 2c. Spisula merriami Packard, * 2. Type and co-type
from Tejon of Salt Creek ‘about twenty miles north of Coalinga, U. C.
Locality 672.

This is a very common species in the Tejon which ranges from the lower-
most Tejon of the Mount Diablo region through the Upper or Siphonalia
sutterensis zone. It was formerly identified as Mactra ashburneri Gabb of
the Chico Cretaceous.

Fig. 2d. Spisula merriami Packard X 2.

This specimen was found at U. C. Locality 2225, Oroville South Table
Mountain.

Fig. 3. Acmaea ruckmani, n. sp., *X 3. Type specimen from U. C.
Locality 2225,

Fig. 4. Lunatia nuciformis Gabb, * 3. This species occurs abundantly
in both Marysville Buttes and Oroville Eocene strata. The specimen figured
is from U. C. Locality 2225.

Fig 5a. Neverita globosa Gabb, & 3. Aperture view, U. C. Locality
2225. A common species in the Siphonalia sutlterensis zone,

Fig 5b. Neverita globosa Gabb, * 1. Back view.

Fig. 6. Neverita secta Gabb, * 8. This species ranges from the lower-
most Tejon of the Mount Diablo region through the Siphonalia sutterensis
zone.

Fig. 7. Cerithiopsis orovillensis, n. sp., * 3. Type specimen U. C.
Locality 2225.

Fig. 8. Chrysodomus martini Dickerson, * 2. This was originally
described as Phos (?) martini Dickerson. It is common at U. C. Locality
2225, South side Oroville South Table Mountain.

Fig. 9. Cancellaria stantoni Dickerson, & 3. U. C. Locality 2225. <A
common species throughout the Tejon.

Fig. 10. Turritella merriami Dickerson, * 1. U.C. Locality 2225. Range,
throughout Tejon group.

[510]

UNIVE CALIF, (PUBL. BULLE; DEPT: 2GEOL, [DICKERSON VOLE. 9, (Pir 39

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EXPLANATION OF PLATE 40

Fig. la. Galeodea sutterensis, n. sp., * 1. Back view.

Fig. 1b. Galeodea sutterensis, n. sp., * 1. Mouth view. :

Fig. 2a. Fusinus merriami, n. sp., * 2. Back view. University of
California Locality 1853.

Fig. 2b. Fusinus merriami, n. sp., * 2. Mouth view. University of
California Locality 1853,

Fig. 8a. Monodonta wattsi, n. sp., * 2. Back view of type specimen.
U. C. Locality 1853. This species is also found in the Tejon of Washington.

Fig. 3b. Monodonta wattsi, n. sp., * 2. Mouth view of type specimen.
U. C. Locality 1858.

Fig. 4a. Drillia ullreyana Cooper, « 2. Mouth view. U. C. Locality
1853. This species is generally found somewhat eroded, The specimen figured
shows less rounded nodes than Cooper’s type and the threads below the
whorl are much stronger owing to better preservation.

Fig. 4b. Drillia ullreyana Cooper, * 2. Back view of specimen figured
as 4a. U.C. Locality 1853.

Fig. 5a. Architectonica ullreyana, n. sp., * 8. View of base. U. C.
Locality 18538.

Fig. 5b. Architectonica ullreyana, n. sp., * 8. Top view.

Fig. 6a. Drillia cooperi, 0. sp., * 1. Back view of type specimen.

Fig. 6b. Drillia cooperi, n. sp., * 1. Mouth view of a small specimen.
U. C. Locality 1858. This species also occurs in the Tejon near Lower Lake,
Lake County, California.

Fig. 7. Ostrea, ef. aviculaformis Anderson, « 3. U. C. Locality 1853.

Fig. 8. Nyctilochus californicus (Gabb), « 8. U.C. Locality 1853. The
specimen figured is a young individual. Formerly known as Tritonium
californicum.

Fig. 9a. Glycimeris marysvillensis Dickerson, * 3. U. C. Locality 1853.

Fig. 9b. Glycimeris marysvillensis Dickerson, « 38. This specimen is
higher than the type, which was a young specimen.

Fig. 10. Corbula parilis Gabb, * 2. U. C. Locality 1858. This is a very
common Tejon form.

Fig, 11. Bittiwm longissimum Cooper, * 3. This beautiful species is the
only one known besides the type, both of which came from U. C. Locality
1858.

[512]

VINING “GALIE. RUBE, BULL. DEPT. GEOL. [DICKERSON] VOL. 9, PL. 40

EXPLANATION OF PLATE 41

Fig. la. Surcula clarki Dickerson, « 3. U. C. Locality 2225, south side
Oroville South Table Mountain. This specimen is a mature form.

Fig. 1b. Surcula clarki Dickerson «* 3. U. C. Locality 2225. Young
specimen.

Fig. 2. Turris inconstans (Cooper), * 2. U.C. Locality 2225. An upper
Tejon species.

Fig. 3a. Turris monolifera (Cooper), * 3. Young specimen from U. C.
Locality 2225.

Fig. 3b. Turris monolifera (Cooper), a mature form from U. C. Locality
2225.

Fig. 4. Drillia orovillensis, n. sp., * 8. Type from U. C. Locality 2225.
Aperture view.

Figs. 5a, 5b, 5c, 5d, 5e. Siphonalia sutterensis Dickerson, U. C. Locality
2225. This is an abundant and characteristic species of the uppermost zone
thus far recognized in the Tejon group of California. The series illustrates
the variation in form with increase in age. 5a, * 2; 5b, & 2; 5c, K 1; 5e X 1.

Fig. 6a. Nyctilochus diegoensis (Gabb), * 2. U.C, Locality 2225. Back
view.

Fig 6b. Nyctilochus diegoensis (Gabb), * 2. U. C. Locality 2225.
Aperture view.

Fig. 6c. Nyctilochus diegoensis (Gabb), «K 2. Back view. This species
was described from the Tejon of Rose Canon, San Diego Quadrangle, from a
horizon which is probably 300 or 400 feet above the base of the Tejon at
this point. It is not a common species. Range, Lower or Middle Tejon
through Siphonalia sutterensis zone.

Fig 7a. Ocinebra nashi, n. sp., * 2. Type from U. C. Locality 2225.
Aperture view.

Fig. 7b. Ocinebra nashi, n. sp. * 2. Back view.

Fig. 8a. Nyctilochus thunani, n. sp., * 2. Type from U. C. Locality
2225. Back view.

Fig 8b. Nyctilochus thunani, n. sp., * 38. Co-type from U. C. Locality
2225. Aperture view.

Fig. 9. Nyctilochus whitneyi Gabb, « 2. U. C. Locality 1853. Tejon
Eocene of Marysville Buttes. This is introduced for comparison with N.
thunani, n. sp. Aperture view.

[514]

UINIVG ‘CALIF. IPUBEY BULLE. (DEPT: ‘GEOL, [DICKERSON] VOL, 9, PL. 41

Migs
Fig.

EXPLANATION OF PLATE 42

1. Metula harrisi, n. sp., * 2.
2. Galeodea tuberculata (Gabb), * 1. This species sometimes has

only two rows of tubercules. The third is feebly developed in this specimen.

Fig.
Fig.

3. Nyctilochus hornii (Gabb), « 2. U. C. Locality 672.
4. Surcula gesteri, n. sp., * 38. Type specimen from Univ. of Cal.

Locality 672. This species also occurs at the type locality of the Tejon group

and in
Fig.
Fig.

672.
Fig.
Hiss
Fig.
Fig.

Bes,

ribbed.
Fig.
Fig.

the Cowlitz phase of the Washington Tejon,
5. Turris stocki, n. sp., K 2.
6. Turritella uvasana Conrad, * 2. Specimen from U. C. Locality

Ta. Turritella buwaldana, n. sp., * 2. Back view of type specimen.
7b. Turritella buwaldana, n. sp., * 2. Aperture view of type.

8. Turritella kewi, n. sp., * 2.

9a. Turritella andersoni, n. sp., X 3. Type specimen.

9b. Turritella andersoni, n. sp., * 3. Variety which is spirally

10a. Turritella lawsoni, n. sp., * 2. U. C. Locality 2295.
10b. Turritella lawsoni, n. sp., K 2. Specimen which shows deco-

ration of medial whorls well.

Fig.
Fig.

11. Cancer(?), sp. a. U. C. Locality 1817.
12. Cancer(?), sp., b. A common but poorly preserved form from

U. C. Locality 1817.

[516]

WINIV CAE, PUBL BUIEE DERT., GEOL. [LICKERSON]) VOLy 9) RE, 42

EXPLANATION OF PLATE 43

Fig. 1. East end of South Table Mountain on right, Table Mountain in
distance and Morris Ravine between the two buttes.

Fig. 2. Looking west along south side of South Table Mountain. Bench
gravels in foreground. Tejon Eocene capped by Older Basalt in center.

[518]

UNIVE SCALIF] IPUBIEY BULE DEPT. GEOL, [DICK ERSONIE VOLES 2, Rew s

EXPLANATION OF PLATE 44

Fig. 1. Looking north at Planicosta Butte, a plateau remnant a mile
south of Merced Falls. Steeply inclined Mariposa slates are seen in the
foreground. The hill is capped by coarse sandstone which yielded an
abundance of Venericardia planicosta merriami,

Fig. 2. Clays of the Ione formation along the Merced River one mile
southwest of Merced Falls capped by a stratum of andesitic tuff breccia.
These clay beds are stratigraphically below the sandstones of Planicosta
Butte shown in the figure above.

[520]

UNIVieCALIB: (PUBL, BUEL, DEP GEOL, [DIGKERISONIE VOLS Re aa:

Fic. 2

EXPLANATION OF PLATE 45

Fig. 1. A view of the Marysville Buttes from Sutter City looking north-
west. This picture shows the buttes rising above the level floor of the Sacra-
mento Valley. South Butte is the highest peak on the extreme left.

Fig. 2. A near view of South Butte taken from the divide on the road
between Sutter City and the town of West Butte. The rounded hills in the
foreground have been formed from the soft tuffs of the Sutter formation.

[522]

UNM CALIEs PUBE. BUEE. DEPT. GEOL, [DICKERSON] VOL. 9, PL. 45

Fig. 1

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EXPLANATION OF PLATE 46

Fig. 1. Looking west from the divide in the ‘Pass’ on road between
Sutter City and West Butte. The ‘Pass’ is cut in the soft tuffs of the
Sutter formation. The hills in the middle ground are composed of the
Sutter formation and possibly Tejon and Chico strata also occur here. The
hill on the right is a rhyolitic neck. The slope of the outer rim of the
andesitic lava flow is seen in the hill on the left.

Fig. 2. A view showing the geological relations of the Sutter formation
to the overlying andesitic lava flow and the underlying Chico. West Butte
is the high peak on the right. The peak in the center is a rhyolitic neck
surrounded on all sides by the Sutter formation. The even sky-line on the
left is due to the gently dipping andesitic lava flow, the outer rim of the
old volcano. The steeply dipping westward strata on the left are Chico
rocks and their mantling cover is the tuffs of the Sutter formation which in
the hill just west of West Butte dip ten degrees west. The Tejon shales
outcrop at a point to the left of the picture,

[524]

UNIV CABIESPUBE: BULLE. DEPT."GEOL, [DICKERSON] VOL. 9, PL. 46

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DUer We a's < ol aiw Cie ae Heels ele ci eha sails eel d=) arena igo a mani: a6 ca a gi
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. A Study of the Skull) and Dentition of Bison aaa with Special
. Faunal Studies in the Cretaceous of the Santa Ana Mountains of §

. Fauna from the Lower Pliocene of Jacalitos Creek and Walthem cite _

tae
. Mesozoic and Genozbi Mactrinae of the Pacifie Coast of North America, )

New Series of the Hip yaTion Group from
Provinces of North A erica, by John Cc.
The Oceurrence of Oligocene in the Contra Cost
Bruce TAM@lark .. Meelis os Pitti so Sie As le PIP een
. Lawson. obs ge
New Horses from the Miocene and Pliocene of California, by John
Corals from the Cretadeous and Tertiary of California and Oregon,
UN Oman. . . swe sla bic oie ao sfiipie oleh gaze. (stata or aisha aa
Relations of the Invertebrate to the Vertebrate Faunal Zones of the J
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Momilamdiere.) 410 ook . Caen) . ee ee eee ol 9B pia oarahe aisle eames

The Owl Remains from Rancho La Brea, by Loye Holmes Miller.,..,....
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Ce Chamimlery ....). s (Witisie afb jn vale’ luk aie RMAAEY bo Mae 2s « catate Sane
the Material from the Pacific Coast, by Asa C. Chandler......... “te 4
fornia, Py War! Leroy Packard.i.). 2... 4. . Josh eee vas a done
Tertiary Vertebrate Fauna of the Cedar Mountain Region in We
iby: Dohme GeweM er riage: .'.) 2). etain ee ely eledeysiole's a ienedene @ elaein wikia) a aa
0, Nomland Ba! sre bies oto Wim 5 /oU6b efdolsL aM aiaN ea al « + /Mieanciny air mann Few eee eee

Leroy | Packard ...-.-).. Pielelinfe ors ieualia eG lleNo te te os ane ee a re a i
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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Vol. 9, No. 18, pp. 525-534, 18 text-figures Issued March 20, 1916

RELATIONSHIP OF EQUUS TO PLIOHIPPUS
SUGGESTED BY CHARACTERS OF A NEW
SPECIES FROM THE PLIOCENE
OF CALIFORNIA

BY
JOHN C. MERRIAM

CONTENTS
PAGE
TEV YGPEXON ROU OS ee SP ee nl eee eT
MEMO Swe ROVETSUSs oD. S)s ececceccs eee ceces eee cece ce ecea-cecetereotee-ceteacee-aeeeesae-easderestes=a-00 526
FENG AUTO TIS DiI) S areeeee tenses eRe ee este mop Mne Iie reer 2S sve Mee eee LAs 2 Do 530
VIG AIS UMC TNC TGS seer ctee se see seta va cece eM re MOC e nce eee eat Perea sees ree tee ee fads canes te es Pec DOF
INTRODUCTION

Recent studies of late Cenozoic Equidaet from the Pacifie Coast
province of the United States have shown the existence of a California
Pliocene horse exhibiting advanced characters in some respects inter-
mediate between those of typical Equus and typical Pliohippus. As
considerable uncertainty has existed concerning the immediate an-
cestry of Equus, any evidence furnished by the new California form
is of special significance, and should therefore be presented in detail
for use in studies on the evolution of this group. It seems particularly
desirable to make available significant new materials received since
the last published reference to this peculiar form.

The studies on West Coast Equidae leading to the statement in the
following article have been greatly facilitated by cordial co-operation
of Professor Henry F. Osborn and Doctor Wiliam D. Matthew of the
American Museum of Natural History. Through courtesies extended
in the use of collections and of organized studies made by the Museum,

1 Merriam, J. C., Trans. Amer. Phil. Soc., n. s., vol. 22, part 3, p. 33, 1915;
also Univ. Calif. Publ. Bull. Dept. Geol., vol. 9, p. 56, 1915.

526 University of California Publications in Geology [ Vou. 9

it has been possible to reach interpretations of new Pacific Coast col-
leetions which would otherwise have been attained with difficulty.
Material assistance in study of the Plhiohippus group was also given
by Professor Richard S. Lull of Yale University through preparation
of excellent casts representing the dentition and feet of the type speci-
men of Pliohippus pernix. It is with pleasure that the writer acknowl-
edges the co-operation of those who have contributed to the furtherance
of this and of other related investigations. It is presumably not an
exaggeration to state that, at this stage in the advance of science, there
can be little hope of material progress in new work without such co-
operation as tends to make the individual investigator merely one
among many assisting in the advance movement in a given direction.

PLIOHIPPUS PROVERSUS, n. sp.
Equus or Pliohippus, sp. Merriam, J. C., Trans. Amer. Phil. Soe., n.s.,
vol. 22, part 3, p. 33, 1915.
Equus or Pliohippus, probably new. Merriam, J. C., Univ. Calif. Publ.
Bull. Dept. Geol. vol. 9, p. 56, 1915.

Type specimen an upper cheek-tooth, M* or M’, no. 21330, from the upper
portion of the Etchegoin formation, locality 2079, North Coalinga region, western
border of the San Joaquin Valley, California.

Cheek-teeth large, long-crowned, heavily cemented. Upper cheek-teeth
slightly curved; mesostyle heavy; fossettes wide to narrow, with moderately
erinkled enamel borders; protocone large, strongly compressed laterally in the
molars, inner border convex or nearly flat. Lower cheek-teeth with short or
long parastylid; metaconid-metastylid column commonly long anteroposteriorly
and narrow transversely, inner groove wide, flat as in Hquus, or somewhat nar-
rowed tending toward the angular form seen in Pliohippus; outer faces of
protoconid and hypoconid either convex or somewhat flattened.

Limb elements, so far as known, much like those of Equus. Unciform facet
of metacarpal II sloping away from the plane of.the magnum at approximately
the angle shown in Hquus. Lateral digits apparently much reduced distally and
feet presumably monodactyle.

As indicated in earlier publications,’ the advanced equid of the
upper Etchegoin finds its nearest American relatives in Equus (Plio-
hippus) simplicidens® and Equus (Pliohippus) cumminsi of the
Blanco Pliocene in Texas. Like the California species the two Texas
forms are known by very imperfect material in which the lower denti-
tion furnishes the better representation. The Blanco species were con-
sidered by Copet to represent ancient types of the Equus group with

2 Merriam, J. C., op. cit., 1915.

3 Referred to Equus by E. D. Cope (Geol. Surv. Texas, 4th Ann. Rep. for
1893, p. 66); but considered as Pliohippus by J. W. Gidley (Bull. Amer. Mus.
Nat. Hist., vol. 14, p. 123, 1901).

4 Cope, E. D., Proc. Amer. Phil. Soc., vol. 30, p. 125, 1892.

1916] Merriam: Relationship of Equus to Pliohippus D271

relatively simple characters. It is interesting to note in this connec-
tion that the peculiar characters of Cope’s Equus simplicidens fur-
nished some of the most important evidence used in determining the
age of the Blanco beds.

The upper cheek-teeth of P. proversus (figs la to 4), as well as of
the P. simplicidens and P. cumminsi types, are distinguished from
those of Pliohippus as represented in the typical form, P. pernix, by
straighter crowns, with heavier mesostyle; tendency to narrowing of

Figs. la to 4. Pliohippus proversus, n.sp. From the upper Etchegoin Plio-
cene of the North Coalinga region, California Figures approximately natural size.

Figs. la, 1b, and le. P*?, no. 22328; fig. la, occlusal view; fig. 1b, outer view;
fig. 1c, posterior view.

Fig. 2. M* or M’, no. 21330, type specimen, occlusal view.

Fig. 3. P*?, no. 21331, occlusal view.

Fig. 4. Portion of an upper cheek-tooth, no. 22329, occlusal view; p, proto-
cone; f, prefossette.

528 University of California Publications in Geology [ Vou. 9

the fossettes ; and especially by the form of the protocone. In typical
Pliohippus the protocone is nearly circular in cross-section in the pre-
molars, but tends to flatten toward the posterior end of the molar
series. In the P. proversus type the protocone is relatively wide trans-
versely in the premolar region, but is flatter or narrower transversely
in all of the cheek-teeth than in P. perniz.

The upper cheek-teeth in P. proversus and in the other members of
this group are distinguished from those of Hquus especially by the
form of protocone (see figs. 13 to 16). In typieal Hquwus this pillar
is normally longer anteroposteriorly, flatter transversely, reaches
farther forward in advance of the isthmus connecting it with the pro-
toconule, and is concave rather than convex on the inner side. There
is also in Hquus a stronger tendency to flattening of the outer faces of
the paracone and metacone, the mesostyle inclines to be thicker, and
the fossettes are usually narrower and have more strongly folded
walls. In EL. stenonis of the Old World and in E. occidentalis of Cali-
fornia, the distinctive characters separating Equus from the P. pro-
versus group are largely reduced in value. The form of protocone in
E. stenonis may approach that of typical Pliohippus in nearly all
characters, as it often tends to do in the milk dentition of modern
Equus. In E. occidentalis the protocone is commonly short antero-
posteriorly and may be nearly as Pliohippus-like as in the known P.
proversus specimens. Both in E. stenonis and E. occidentalis the com-
bination of all characters present in any given tooth is, however, com-
monly such as to indicate closer relation to modern Equus forms than
to the P. proversus group.

The lower cheek-teeth of the upper Etchegoin P. proversus re-
semble those of a series described by Cope from the Blanco Phocene of
Texas, and referred to P. simplicidens. The Blanco teeth (fig. 17)
are characterized by their considerable size, heavy cementation, and
by the anteroposterior length of the metaconid-metastyhd column.
The metaconid-metastylid column commonly shows a rather sharply
angular internal groove. Cope’ considered the character of this
column distinetive of P. simplicidens, in contrast with the Equus
forms of the Pleistocene. In P. simplicidens the outer walls of the
protoconid and hypoconid are convex to flattened.

Tn the lower teeth of the P. proversus type from the upper Etche-
goin the crowns are large, long, and heavily cemented. The metaconid-
metastylid column in a number of specimens (figs. 5, 6, and 7) is wide

5 Cope, E. D., Geol. Surv. Texas, 4th Ann. Rep. for 1893, p. 66.

529

-clationship of Equus to Pliohippus

‘ream

Mei

1916]

=a Re 4
See
Figs. 5 to 10. Pliohippus proversus, vn. sp. Upper Etchegoin Pliocene, North Coalinga, California. Figures natural size.
g PI g g
Fig. 5. Inferior cheek-tooth, no. 22316, outer and occlusal views. Fig 8. M,?, no. 22312, outer and ocelusal views.
Fig. 6. P,?, no. 21332, occlusal view. Fig. 9. M,, no. 22314, outer and occlusal views.
Fig. 7. Inferior molar, no, 22330, outer and occlusal views. Fig. 10. My, no. 21333, occlusal view.

530 University of California Publications in Geology [ Vou. 9

anteroposteriorly and the internal groove is broad and flat. The
width and flatness of the groove sometimes considerably exceed that
in the simpler variations of Equus. In other lower cheek-teeth from
the upper Etchegoin (figs. 8, 9, and 10) the inner groove of the
metaconid-metastylid column is sharper than in Hquuws and more
nearly resembles that in typical Pliohippus.

The form of the lower cheek-teeth in P. proversus is close to that of
the Blanco material referred by Cope to P. simplicidens. The two
types may be specifically different, but they apparently represent a
group, which, as is shown in the upper cheek-teeth, appears separable
from Equus, and does not correspond closely to typical Pliohippus.

Figs. 11 and 12. Pliohippus proversus, n. sp. From the upper Etchegoin Plio-
cene of the North Coalinga region, California. Both figures one-half natural
size.

Fig. 11. Left metacarpal III, no. 22318, anterior and proximal views.

Fig. 12. Astragalus, no. 22334.

RELATIONSHIPS

The horses referred to the Pliohippus proversus type from the
upper Etchegoin Pliocene of California are distinct from all of the
most advanced horses of the lower Etchegoin and Ricardo Pliocene
stages of the Pacifie Coast province. There is, however, in certain
characters sufficiently close resemblance to some of the Ricardo species
to suggest that the upper Etchegoin form may be derived by modifica-
tion from one of the early Pliocene Pacific Coast species near Plio-
hippus tantalus or P. fairbanksv.

1916] Merriam: Relationship of Equus to Pliohippus 53]

Fig. 13. Pliohippus proversus, n. sp. M' or M’, type specimen, no. 21330,
natural size. Upper Etchegoin, North Coalinga region, California.

Fig. 14. Pliohippus simplicidens (Cope). Superior premolar?, natural size,
Blanco Pliocene, Texas. (After Cope.) The inner single dotted line in recon-
struction of the protocone represents the writer’s interpretation of this pillar.

Fig. 15, Pliohippus cumminsii (Cope). Superior molar, natural size. Blanco
Pliocene, Texas. (After Cope.)

Fig. 16. Equus occidentalis Leidy. P* to M’, no. 21001, natural size. Pleisto-
cene, Rancho La Brea, California.

Fig. 17. Pliohippus referred to simplicidens (Cope). Lower cheek-tooth
series, one-half natural size. Blanco Pliocene, Texas. (After Cope.)

Fig. 18. Hquus occidentalis Leidy. Lower cheek-tooth series, no. 12269, one-
half natural size. Pleistocene, Rancho La Brea, California.

Doe University of California Publications in Geology [ VoL. 9

In considering the relation of P. proversus to forms of American
faunas later than the upper Etchegoin, it is interesting to note that
Equus occidentalis of the California Pleistocene represents the North
American species of Equus in which the characters of the cheek-teeth
show greatest simphcity. The gap between P. proversus and EF. occi-
dentalis is too wide to permit the conclusion that the later of the two
is derived immediately from the earlier (see figs la to 10, 13, 16, and
18). In this connection it should be noted that the upper Etchegoin
stage, in which P. proversus occurs, 18 separated from the Pleistocene
horizon containing FE. occidentalis by the Tulare formation, represent-
ing a thickness estimated by Arnold and Anderson® to include at least
three thousand feet of strata.

Of the Old World forms later than the upper Etchegoin stage of
the Pliocene, the type most nearly approaching P. proversus is Equus
stenonis,” described from the Pliocene and Pleistocene, and repre-
senting the least progressive Old World type of the genus Equus. In
some respects EH. stenonis approaches the P. proversus type more
closely than does the American EF. occidentalis. This may be due to
the origin of H. stenonis either in America or in Eurasia at a time
earlier than the Pleistocene stage of H. occidentalis. The Tulare
formation of California represents such a time in the geologic sequence.
The fauna of the Tulare is as yet very imperfectly known, and no
horse remains have been reported from these beds. It is probable that
a stage less advanced than FH. occidentalis and more progressive than
P. proversus will yet be obtained from the Tulare section.

The similarity in general characters of Pliohippus proversus of
the upper Etchegoin to the two Pliohippus species of the Blanco Plio-
cene, considered with similarity of the vertebrate faunas of the Blanco
and upper Etchegoin leaves little rcom for doubt that P. proversus. P.
simplicidens, and P. cumminsii represent closely allied forms of nearly
the same epoch. In the characters of both upper and lower cheek-
teeth the forms of this group are intermediate between typical Plio-
hippus and typical Equus, and represent the nearest approach to the
Equus type found among American Tertiary horses. The geologic
occurrence of these species represents a stage following the time of
maximum development of Pliohippus and apparently preceding the
earliest known occurrence of true Equus. The evidence presented in
this sequence of horse types in America indicates that some, at least,

6 Arnold, Ralph & Anderson, Robert, U. 8. Geol. Surv. Bull. 398, p. 147, 1910.

7See Major, Forsyth, C. J., Abhl. Schw. Palae. Ges., vol. 4, Taf. 1 and 2,
1877; also ibid., vol. 7, Taf. 7, 1880.

1916] Merriam: Relationship of Equus to Pliohippus 533

of the Equus forms of this continent were derived from Pliohippus
along a line of evolution passing through or near the P. proversus
group. Whether, as has been held by several writers, certain Old
World forms included in Equus had an independent origin by way of
Hipparion, may still be a field for discussion. Hqwus sivalensis and
E. namadicus reported from the uppermost Siwalik beds of India,?
are held to represent true Equus, and have been considered as possible
derivatives from Hipparion. Much remains to be known concerning
the characters of these forms, as also concerning their exact occur-
rence in the geologic scale. Should the uppermost Siwalik fauna con-
taining species referred to Equus prove to be late Pliocene there would
seem to be abundant opportunity for origin of the Indian forms from
an American type of the geologic stage represented by P. proversus, as
the upper Etchegoin beds lie below the great Tulare section, which has
been presumed to be mainly, if not entirely, Pliocene.

8 The line of evolution from Pliohippus to Equus has been recognized by
many writers, although the stages of transition have not been fully indicated.

9See Lydekker, Richard, Palaeontologia Indica, ser. 10, vol. 2, part 3,
pp. 21 to 380, pls. 14 and 15, 1882; also Pilgrim, Guy E., Records Geol. Surv.
India, vol. 43, part 4, p. 324, 1913.

534 University of California Publications in Geology [ Vou. 9

MEASUREMENTS
P. pro-
versus E. occi-
P. simpli- P. cum- No. dentalis
cidens minsii 22328 No. 21001
P?, anteroposterior diameter -......00..--ccce. cece eee 33. mm. 30.4
PEN EGAN VErSen cient ely sere cereete eee see se see 28.5 28.2
P*, anteroposterior diameter of protocone.. 0.200 oe al0.7 11.9
No.
21331
P*, anteroposterior diameter —....................... aQ3if mm) ee 30.2
P* transverse diameter - 2.22222 seeceecceecceccceccce G2 eee 29 28.4
P*, anteroposterior diameter of protocone.. al2 0000 on. a10.2 12
No.
1021330
M’, anteroposterior diameter -......22..0.-2::002 00 see 22 30 26.3
IME GLANS VerSe Game ere cesses estes seer wees eee a25.5 27 27.1
M', anteroposterior diameter of protocone.. ...... 9.5 13.8 11.1
Me AMLCKOWOSUCLION CA mMetOr. eer: ceeeresceree. cee) eeeasc geese essa 27.5
INE, amneehaichendeiey ebichan\ereye ete ee ee 26.8
M, anteroposterior diameter of protocone.. 22. 00 eee ee 12.8
No.
12269
P., anteroposterior diameter -............-......--- 39) 0322" ee 34
Pe GLAMIS Verse ClamMet Gis 2-csceesercseees-eeacee eae 16:55) eee ees 17.8
P., anteroposterior diameter of metaconid-
mietastylid) Col wim) 2: c22ecereeesseeeee-= N65ue | <a) ee 15.9
P,, anteroposterior diameter -....---.--2.-... SBE | aes 8 Sas 29.8
P,, transverse diameter ........-......-2-...----+----- ef = eee | ee ieee 17
P,, anteroposterior diameter of metaconid-
ana orfalsienyAbK Gl (Ko bNAAN ON eens eee ee 20° Se ese pees 18.3
No.
21332
P,, anteroposterior diameter -...............-.----- B30 34.1 29.5
P,, transverse diameter -.........- : iG feet | 18.2
P,, anteroposterior diameter of metaconid-
MebASt YU tCo uM ee sets erence eens 20° & See 17.7 Weft
No.
21333
M,, anteroposterior diameter -..........-.--.....---- 32000” 27.5 26
M,, transverse diameter 00.2... Heeeies 15:5)" ee RE 17
M,, anteroposterior diameter of metaconid-
me tastry lndis com ean eerce renee 16:5 = Pe = 13.9
No.
22314
M., anteroposterior diameter ~............-.------- Si 27 27
Mai tramsverse GlamMetet ce. .c--cssteecreer eee 1553; ) ee 12.8 17.3
M., anteroposterior diameter of metaconid-
MN HAS ys Cl eC OM UMN te eeeceeececemeneesceeecere Wi ee 13.6 14.8
No.
21333
M,, anteroposterior diameter -..........----.---- BY abezses 36.2 31.5
M,, transverse diameter .........-.-2-2------------- da es 13.8 16
M,, anteroposterior diameter of metaconid-
mietast yaluderc OUI tere eeecen-eeetec etna 16:5) ee 14.7 13.4

a, approximate.
10 M' or M’.
Transmitted March 14, 1916.

INDEX*

Titles of papers in this volume, and names of new species,
are printed in a bold-faced type.

Acila gabbiana, 481; figure of, opp.
504.

Acmaea ruckmani, 488; figure of, opp.
510.

Actaeon moodyi, 488; figures of, opp.
508.

Actaeonella oviformis zone, 142, 144,
150, 154.

Aelurodon, figure of, 174.

Agasoma gravidum beds, in the vicin-
ity of Walnut Creek, California,
12; uneonformity between the
Area montereyana beds, 13, 21.

Agasoma gravidum zone, 9; correla-
tion of fauna of with part of
Astoria series, 10; faunal re-
lationship of, to Area mon-
tereyana zone, 14; relation of,
to Lower Miocene of Southern
California, 15; correlation of
fauna of, with fauna of Oligocene
of Oregon and Washington, 17;
species common to both, 19; age
of fauna of, 20.

Agriocharis, new genus proposed for
American ocellated turkey, 96.

Alaska, Stepovak series, mactrine
species from, 274.

Aliso eafion, California, section of
Cretaceous along, 142.

Alluvial embankments, encroachment
of, 28; growth of, 30, 38; incor-
poration of sand dunes in, 32;
stripping of the fans, 34; twinned
embankments, 39, ideal cross-sec-
tion of, 40, formational, and de-
positional, stratification in, 41,
false bedding, 41; transverse flut-
ing of, 41.

Alnus, 414, 415.

Aluco pratincola, 99.

Amauropsis alveata, 368; figure of,
opp. 508.

American Museum of Natural History,
525.

Anderson, F. M., cited, 16, 54 note 1,
78, 138, 139, 149 note 15, 157,
200, 370, 422.

Anderson, R., cited, 78, 200, 369, 370,
532 note 6; views on type Tejon,
420.

Anticline Ridge, California, 82.

Antelopes, ‘‘roman-nose’’ dorsal con-
tour a characteristic of, 120.

Antiloeapra, compared with Capro-

meryx, 112.
Americana, 117.
Aphelops?, sp. A, 181; figure of, 180;
Sp. B, 181; figure of, 180.
Aplodontia?, 177; figures of, 178.
Aralia, 144.
whitneyi, 416.

Arauearioxylon, 415,

Area Clarki, 481; figure of, opp. 506.
hornii, figure of, opp. 504.

Avea montereyana beds, in vicinity
of town of Walnut Creek, 13.
Arca montereyana zone, 9, 10, 14, 21;
faunal relationship of to Aga-

soma gravidum zone, 14.

Architectonica, ullreyana, 487; figure
of, opp. 506; figures of, opp. 512.

Arid regions, epigene forms in, 25,

Arkose, 39.

Arnold, Ralph, cited, 10, 11, 17, 19, 54
note 1, 64, 78, 200, 370, 371, 436,
532 note 6.

Arrialon group of Southern India,
157.

Arroyo Trabueo, California, 139.

Artocarpus, 414.

Asio, 102.

flammeus, 102, 103.
wilsonianus, 103.

Astoria series, correlation of part of,
with fauna of Agasoma gravidum
zone, 10; three formations of, 11;
correlation of shale with Oligo-
cene, 10,

Astralium arnoldi, 204; figures of,
opp. 212.

Astrangia insignifica, 65; figures of,
opp. 70.

Aueella, 151.

Baker, C. L., 162.

Balanophyllia, variabilis, 66, 379;
figures of, opp. 72; zone of, in
the California Tejon, 366, 375;
species in, 378; specimens from,
385,

Barstow Miocene, 50.

Bassariscus nevadensis, 175, figures
of, 176.

Bear River, upper Miocene of, 240;

fauna of, 240, 251-258; eorrelation
of, 259.

Beeker, G. F., cited on the age of
the Tejon, 369.

* Univ. Calif. Publ. Bull. Dept. Geol., vol. 9.

Index

Betula, 415.

Bison, individual and sexual varia-
tion in, 122-124; measurements:
of skulls, opp. 126; of teeth of
upper jaw, 132; of teeth of lower
jaw, opp. 134.

Bison antiquus, 122, 124, 135; era-
nium, 126; figures of, 127, 128,
129; dentition, 131; figures of,
1S

bison, 122; figures of, 129.
bonasus, 124.

californicus, 124.
latifrons, 131.

regius, 131.

Bison Antiquus Leidy, A Study of
the Skull and Dentition of, with
Special Reference to Material
from the Pacific Coast, 121.

3ittium longissimum, figure of, opp.
pyle

Black Star Cafion, California, 140.

Blake, Eocene fossils sent to Conrad
by, 368.

Blake, W. P., cited on region south
of Merced Falls, 399.

Blakeley formation of Weaver, 11,
19.

Blanco Plocene
from, 528.

30owers, S., cited, 149 note 13.

Brandt, J. F., cited, 121.

Bubo virginianus, 100.

Buek, T. H., acknowledgement
assistance, 162.

Busycom? blakei, 368.

Butano formation, Santa Cruz Quad-
rangle, possibly a member of
coast group, 463.

Butte County, California, 153.

Butterworth, E. M., 54.

Buwalda, J. P., 162; cited, 163 note
[eGo mlloommotense ol 0:

Calabasas Quadrangle, Tejon strata
reported in, 469.

Californian Academy of Sciences, col-
lections of fauna from Oligocene
of Oregon and Washington, 17.

California, University of, collection
of mactrinae, 263.

Calliostoma etchegoinensis,
ure of, 88.

Callista voyi, 264, 283, 284.

Cancer? sp. a, sp. b, figures of, opp.

of Texas, Equidae

of

85; fie-

516.
Cancellaria stantoni, figure of, opp.
510)

Canid, sp., 174.
Aelurodon? sp., 174.
Cape Blanco, Oregon, Later Neocene
and Quartenary deposits of, 245.
Capromeryx Material from the
Pleistocene of Rancho La Brea,
Notes on, 111.

[536]

Capromeryx minor, 111.

Capromeryx, skull and horn-core, 112,
figures of, 113; jaws and den-
tition, 114, figures of, 115; ver-
tebrae and ribs, 117, 118; arches,
118; limb bones, 118, 119.

Cardium gabbi, type of Pseudo-
cardium, 264, 305; description
of, 304.

linteum, 368.
marysvillensis, 482.
Carmelo series, Lawson’s opinion on,
464,
Carpenter, P. P., cited, 265 note 9.
Cedar Mountain, Nevada, vertebrate
fauna, composition of, 168; re-
lation to its environment, 168;
stage of evolution and relation-
ships of, 169; relative age of,
171; deseription of collecting lo-
ealities, 197.
Cenomanian, 157.
Cerithiopsis dumblei, 489; figure of,
opp. 508.
orovillensis, 489; figures of, opp.
510.
Chandler, A. C., 111, 121.
Chapman, R. IT., cited, 164.
Chico Creek, California, 139,
159; fauna, 150, 154, 155.
Chico group of California Cretaceous,
138, 273, 405; section of, along
Santiago-Aliso divide, 142.
Chione elsmerensis, figures of, opp.
210, 212.
Chysodomus coalingensis, 205; figure
of, opp. 212.
martini, 488; figure of, opp. 510.
Cima, California, mountain ridge
buried in alluvial waste, 26.
Cinnamomum, 414.
Clark, W., cited, 369.
Clavatula(?) californica, 368.
Coal Mine Cafion, Coal Mine Hill,
California, 140.
Coalinga, California, 274; north, 526.
Coalinga Quadrangle, Tejon localities
in, 429. See also Tejon.
Colorado group, 157.
Condon, Thomas, Hipparion
mens in collection of, 7.
Conrad, T. A., cited, 269 note 5, 300
note first recognition of
Eocene on Pacific Coast, 368.
Cooper, J. G., cited, 149 note 14, 369,
370, 436.
Cope, E. D., cited, 3 footnote 1, 189
notes 8, 9, 195 note 11, 526 note 3.
Corals from the Cretaceous and Ter-
tiary of California and Oregon,
59.
Corals, Pacific Coast, table showing
stratigraphic position of, 60.
Corbula parilis, figure of, opp. 512.

153,

speci-

25;

Index

Cornus, 414.
Correlation of Pliocene of Middle

and Northern California, 247;
table of, 259.
Crassatella alta, 368.

uvasana, 368.
Crassatellites lillisi, 482; figure of,
opp. 504.
mathewsoni, figures of, opp. 504.
Crepidula inornata, 489; figures of,
opp. 508.

Cretaceous, Upper, 139; along the
Santiago-Aliso divide, 142;
fauna from the Santa Ana

Mountains, 142, 155; Indian, 143.

Cupressinoxylon, 415.

Cymbophora, typical species of, 276;
descriptions of, 298.

ashburnerii, description of, 298.

Daggett, F. 5., acknowledgment of
assistance, 112.

Dall, W. H., cited, 10, 11, 17, 19, 264,
265, 266, 271, 272, 277, 370; tax-
onomie system of, 263.

Dendryophyllia hannibali, 67; figures
of, opp. 76.

tejonesis, 67; figures of, opp. 72.

Dentition of Bison antiquus Leidy,
121.

Desert cycle, concept of, 34; panpan
a stage of degradation of, 34,
44; rock terraces explained by
diastrophic of climatie inter-
ruption of normal course of, 34.

Desert mountains, chronological
classification of, 26; steepness of
rock slopes, 30; explanation of
rock terraces on, in California,
Nevada, Arizona, New Mexico,
Mexico, 34.

Diablo, Mount, California, 274.

Dickerson, R. E., 363; acknowledg-
ment of assistance, 61; cited,
139, 274, 292, 295, 296, 304, 312
note 26, 370, 371.

Diller, J. S., cited, 10, 152, 156, 369,
409, 415, 461.

Dipoides, near tortus, 177; figures of,
177.

Dosinia alta, 368.

Drillia cooperi, 491; figure of, opp.
512.

orovillensis, 490; figure of, opp.
514,
ullreyana, figures of, opp. 512.

Dumble, E. T., cited, 370; on Eocene
Shasta, 422; Tejon species listed
by, from Topila, Mexico, 477.

Elder Creek beds, California, 151.

Eldridge, G. H., cited, 370, 463.

Ellensburg formation, 6.

Elotherium, 414. :

English, W., cited, 201.

[537]

Eocene, Lower, Upper, in the Santa
Ana Mountains, 139; Martinez,
mactrine species from, 274; Clai-
borne, some species of, 368; of
Oroville South Table Mountain,
location, 388; historical, 389,
stratigraphy, 390, faunal rela-
tionships, 392. See also Tejon
Eocene.

Epigene Profiles of the Desert, The,
23.

Epigene profiles, elements of, in arid
regions, 26; playa, 26; acelivity
of, 27; climatie control rela-
tively slight under certain con-
ditions, 27; wind an inefficient
agent, 27; effect on, of difference
of altitude of playas, 33. See
also Alluvial embankments, Rock
slopes, Arid regions, Panpan,
Talus, Rainless regions, Desert
eyele.

Epitonum tejonensis, 491; figure of,
opp. 508.

Equidae, 525; from the Blanco Plio-
cene of Texas, 528.

Equus or Pliohippus, 56; figures of,
57; transition between, 58; re-
lationship between, 525.

Equus (Pliohippus) eumminsii, 526.

eurystylus, 4.

oceidentalis, 528; figure of, 531;
measurements of, 534.

simplicidens, 527.

stenonis, 528.

Esmeralda formation, 163; plans of,
166.

Etchegoin formation, 200, 275, 526;

relation of invertebrate faunal
zones, 77; invertebrate faunal

zone, 81; of the Lower Middle
Zone, 82; ot Sargent oil field,

244, fauna of, 244, 245, 251-
258; correlation of, 259.
Etchegoin ranch, California, 78.
Ezo, Island of, 157.
Fairbanks, H. W., 56; cited, 436, 462.

Fanglomerate, 38.
Fasciolaria bilineata, 493; fieures of,

opp. 506.
Fauna, from the Lower Pliocene at
Jacalitos Creek and Waltham

Canyon, Fresno County, Califor-

nia, 199; of Sargent oil field,
244, 245, 251-258; San Pablo,
mactrine species in, 274, 276;

Recent, mactrine species in, 275;
San Pedro, mactrine species in,
275; of the four Tejon zones,
366, 373-379. See also San
Diego, Shasta County, Tehama
County, Tejon fauna, Tejon
Eocene, Tejon in California.

Index

Fauna, of Merced series; type sec-
tion, 226; of Bolinas Bay, 230;
of Ano Nuevo Bay, 231; of Pil-
lar Point, 232; of Sargent oil
field, 233; of Wildcat series, 237,
238, 239; of Pliocene of Middle
and Northern California, 251-—
258.

Faunal Studies in the Cretaceous of
the Santa Ana Mountains of
Southern California, 137.

Felid, sp. A, sp. B, 175; figures of,
175.

Ficopsis cooperii, 492; figure of, opp.
506.

Ficus, 414.

Fissuridea subelliptica, 205; figures
of, opp. 212.

Flabellum californicum, figures of,
opp. 72.

merriami, 62; figures of, opp. 70.

Fusinus ecalifornicus, 368.

merriami, 493; figures of, opp. 512.

Gabb, W. M., eited, 138, 153, 368,
436.

Galeodea sutterensis, 492; figures of,
opp. 512.

tuberculata, figure of, opp. 516.

Gas Point, California, Chico beds at,
Ip}

Gastrochaena, 143.

Gault types found in Chico forma-
tion, 157.

Gester, G. C., acknowledgment of
assistance, 367.

Gidley, J. W., cited, 3 note 2, 4 note
3, 526 note 3.

Hilbert, cited, 28.

Glycimeris zone, list of invertebrate
fauna of, 81.

Glycimeris fresnoensis, 483; figures
of, opp. 504.

hannibali, 483; figures of, opp. 504.
marysvillensis, figures of, opp. 512.
perrini, 482; figures of, opp. 504.
sagittatus, figures of, opp. 504.

Goniopora vaughani, 68; figures of,
opp. 70.

Gorgonia, figures of, opp. 72.

Gorgonidae, 69.

Graben, 41.

Gravels of interrhyolitic age, 411.
See also Tertiary gravels in the
Sierra Nevada.

Grinnell, J. cited, 98.

Hannibal, Harold, cited, 10, 11, 17,
19.

Harding Cafion, California, 140.
Harris, G. D., cited, 869; on corre-
lation of Tejon Eocene, 475.
Heilprin, A., cited, 369; on correla-
tion of Tejon Eocene, 475.
Hemimactra, 276; descriptions of,

283.

lenticularis, 264; descriptions of, 302.
occidentalis, 264, 288.

Henley, California, typical Lower
Chico locality, 139; equivalent
to certain other beds, 157.

Hipparion condoni, 6; figures of, 6.

mohavense callodonte, 54; figure
of, 53.
platystyle, 5.

Hipparion Group, New Species of,
from the Pacific Coast and Great
Basin Provinces of North Amer-
icasele

Horsetown beds of Shasta group of
California Cretaceous, 138, 151,
152, 158, 159, 273.

Hulen Creek, California, fauna of,
closely related to fauna of
Horsetown, 152, 153.

Hypohippus (Drymohippus) nevaden-
sis, 182; figures of, 182, 184.

Hypohippus, near osborni Gridley,
186; figure of, 180.

Tlingoceros, 118.

Inoceramus, 141.

Tone formation of California, 387; at
type locality, 394; Turner’s de-
seription of, 394; occurrence of
Eocene fossils in, 397; relation
of auriferous gravels to, 398;
near Merced Falls, 398; in the
vicinity of Bear Creek, Merced
County, 399; deep-water equiva-
lent of, at Marysville Buttes,
403, stratigraphy, 403, Sutter
formation, 404, historical geol-
ogy, 405; summary of fauna of
Siphonalia sutterensis zone, 406;
correlation of, and the aurif-
erous gravels, 409; summary of
conclusions regarding, 417.

Ione Valley, Nevada, 163.

Tone Eocene Sea, map showing prob-
able extent, 473.

Jacalitos Creek, California, evidence
helping to fix position of beds
on, 200.

Jacalitos formation, invertebrate
faunal zone of, 81; thickness of,
201; palaeontologie age, 204;
species ranging through to Etch-
egoin, 275.

Pliocene, figure of type specimen
form, 2.

Jackson Quadrangle, geological map
of portion of, 396.

Jasper Creek, California, Jacalitos
beds on, 201.

John Day, Oregon, fauna, 152.

Johnson, H., cited, 370.

Juglans, 414.

Kern River, Kern County, California,
mactrine species reported from,
274.

Index

Kew, W. 8. W., acknowledgment to,
437.

Klamath province in Eocene time in
California, 471.

Knowlton, F. H., cited, 166 note 5,
167; floras listed by, determined
as from San Pablo formation,
413, localities where found, 416;
on life conditions of flora of
auriferous gravels, 414.

Knoxville beds of Shasta group of
California Cretaceous, 138, 151;

Paskenta horizon, 138; — sub-
Knoxville ‘horizon, 138.
La Jolla, Point, California, 139.
Later Neocene deposits of Cape

Blaneo, Oregon, 245.
Laurus, 415.
Lawson, A. C.,

463.

92.

eis

cited, 9, 12, 370,

Leda fresnoensis, 483; figures of,
opp. 504.
gabbi, figure of, opp. 504.
Lepus, near vetus Kellogg, 179; fig-

ure of, 180.

Leuciscus, 166.

turneri, 167.

Lillis, Helen,
482.

Lilljeborg, cited, 121.

Lincoln formation of Weaver, 11, 20.

Lindgren, W., cited, 369, 390, 409; on
uneertainty of vertebrate locali-
ties, 414; on Tertiary topography
of the Sierra Nevada, 415.

Liopistha, 143.

Liquidambar, 414.

Los Angeles Basin in Eocene time,
468, 471.

Lueas, F. A., cited 121, 166 note 6.

Lull, R. 8., acknowledgment of as-
sistance, 526.

acknowledgment to,

Lucina diegoensis, 484; figures of,
opp. 506.
taffena (Myrtea), figure of,
opp. 504.

packi, 484; figure of, opp. 504.
Lunatia nuciformis, figure of, opp.
510.
Lutraria truncata, 264; deseription
of, 300; ventricosa, 281.
Lydekker, R., cited, 533 note 9.
McGee, cited, 34 note 6.
McLaughlin, cited, 370.
Mactra (Spisula) alaskana, 283.
alata, 281.
albaria, 264; deseription of, 290.
ashburnerii, typical species of
Cymbophora, 264; deseription of,
298.
augusta Deshayes, 280.
californica, 264, 268, 275, 278, 279,
280; graph of, 269; figures of,
322.

[539]

satilliformis, 264.

coalingensis, 265;
301.

deshayesii, 278.

diegoana, 264; deseription of, 290.

dolabriformis, 275, 279; figures of,
314.

exoleta, 264, 275,
of, 314, 316.

faleata, 264; deseription of, 297.

fragilis, deseription of, 278.

gabbiana, 265; description of, 299;
differentiation from Spisula ash-

description of,

281, 283; figures

burnerii, 299.
eabiotensis, 264; description «%
Silos

gibbsana, deseription of, 310.
hemphillii, 265, 287.
montereyana, 265; description of,
Bull
nasuta, 264, 275,
of, 314.
ovalis, 283.
planulata, 264; description
polynyma, 264; description
solida, deseription of, 283.
solidissima, deseription of, 283.
stantoni, 265; deseription of, 311.
stultora, description of, 278; fig-
ures of, 314.
tenuissima, 264,
of, 312.
trampasensis, description of,

278, 280; figures

)

of, 293.
of, 293.

274; deseription

9Q09.

SOL,
figures of, 322.
typiea, description of, 304.
warrenana, 264.
Mactracea, deseription of, 277.
Mactrella, widely separated from
Mactratoma, 276; description of,
281.

exoleta, 281.
Mactridae, description of, 277; hinge
of, a basis for eclassifieation, 265.

Mactrinae, Mesozoie and Cenozoie,
263.
Macetrinae, history of, 273; table

showing geologic and geographic
range, opp. 274; phylogeny, 276—
7; deseription, 278. See also
Mactrine hinge, Maetrine shell.

Mactrine (mactroid) hinge, detailed
deseription of, 266; hinge plates,
271; cardinal tooth, 272, 273;
least variable within limits of
single species, 277.

Mactrine shell, variations of, 267;
eraphs illustrating, 269; pallial
sinus, 271.

Mactromeris, descriptions of,

Mactrotoma, widely separated from

9Q9

=00.

Mactrella, 276; deseription of,
278.

Madripora_ solida, 64; figures of,
opp. 74.

Index

Magnolia, 414.
lanceolata, 416.

Marcia (?) conradi, 484; figure of,
opp. 508.

Marcon, J., cited, 369.

Martin, Bruce, 17, 215; cited, 296.

Martinez Kocene, mactrine species

from, 274.

Martinez formation, 139; relation of

fauna to Tejon fauna, 455.

Marysville Buttes, historical geology

of, 405.

Matthew, W. D., acknowledgment of

assistance, 525,

Merced series, 222; of the type local-
ity, 223; fauna of, 226, 251-258,
275; list of fossils from, 229;
correlation of, 259; of Bolinas
Bay, 230; fauna of, 231, 251-
258; of Afio Nuevo Bay, 230,
fauna of, 231, 251-258; of Pil-
lar Point, 231, fauna of, 232,
251-258; of Sargent oil field,
232, fauna of, 233; of the Santa
Rosa Valley, 233.

Meretrix californiana, 368.

hornii, figure of, opp. 508.
uvasana, 368.

Merriam, J. C., 1, 49, 161, 525; cited,

5 note 4, 9, 11, 12, 16, 77, 84

note 6, 152, 164, 167 note 7,
204, 525 note 1, 284, 293;
acknowledgment of assistance,
61, 112, 263, 367.

Merychippus, sp., 186; figures of,
187.

Merychippus? or Hipparion?, figures
of, ST.

intermontanus, 50; figures of, 51.
sumani, 49; figure of, 51.
Merycodontidae, 194.
Merycodus sp., 117; figures of, 196.
fureatus, 194; figures of, 196.
near necatus, 197; figure of, 196.
Mesozoie and Cenozoic Mactrinae of
the Pacific Coast of North Amer-
ica, 261.

Metula harrisi, 494; figure of, opp.
516.

Micromactra, 279.

Miller, L. H., 89, 97, 105; cited, 173.

Miocene, Barstow, 50; Upper, or

Bear River, 240, fauna, 240, 251—
258; period of differentiation of
mactrinae, 277.

Mitramorpha parsonsi, 495; figure of,

opp. 508.
Mohave Desert, California, 49, 50,
54.

Monodonta wattsi, 494; figures of,
opp. 512.

Monterey formation, 9; shale, 16.

Morris Ravine, California, conditions
of sedimentation in, 390.

[540]

Mulinia, descriptions of, 304.
Mulinia alta, differentiation
from M. densata, 306; descrip-
tion of, 307; differentiation from
M. densata, M. pabloensis, M.
undilifera, 308.
densata, 264, 268, 275, 310; graph
of, 269; deseription of, 304;
hinge plate of, 306; differentia-
tion from M. pabloensis, M. alta,
M. undilifera, 306, from M. alta,
308; figures of, 348, 350, 352,
354, 356.
var. minor, 265; occurrence of,
in Coalinga district, 274;
described bv Arnold from
the Vaqueros, 305; deserip-
tion of, 307.

275;

landesi, 274, 275; description of,
309.

oregonensis, 265; description of,
304; within the range of M.
densata, 305.

pabloensis, 275; description of,
309; resemblance to M. densata,
310.

trampasensis, 275.

undilifera, 275; differentiation
from M. densata, 306, 309, from
M. alta, 308, 309; description

of, 308; figures of, opp. 358.
ventricosa, 281.
Murex (Ocinebra) nashi, 495,
perangulatus, 206; figures of, opp.
214,
Mustelid, 175; ngures of, 174.
Myazone, 83.
Mylagaulus?, sp., 177.
Mytilus humerus, 368.
kewi, 206; figure of, opp. 210.
Nash, Mrs. L., acknowledgement to,
163.
Natica aetites(?), 368.
alveata, 368.
convexa, 86; figures of, opp.
88.
gesteri, 496; figures of, opp. 508.
eibbosa, 368.
hannibal, figures of, opp. 508.

orbicularis, 207; figures of, opp.
212.
uvasana, figure of, opp. 508.
Neocene, Later, deposits, at Cape

Blanco, Oregon, 295,

Neogyps errans, 108.

Neohipparion gidleyi, 1; figure of, 2.
leptode, 3; figure of, 4.
montezumae, 3.
molle, 3, 83, 85; figure of,
sinclairii, 3.

Neophrontops americanus, 106; tar-
sometatarsus, 106; tibiotarsus,
108, humerus, 108; figures of,
107.

9

Index

Neverita globosa, figures of, opp.

510.
secta, figure of, opp. 510.

New Horses from the Miocene and
Pliocene of California, 49.

Newberry, J. 8., cited, 369.

Niagara escarpment, 27.

Nomland, J. O., 59, 77, 199; cited,
204.

Notes on Capromeryx Material from
the Pleistocene of Rancho La
Brea, 111.

Nubbins, 38.

Nyetilochus californicus, figure of,
opp. 512.

diegoensis, 497; figures of, opp.
514.

hornii, figure of, opp. 516.

thunani, 496; figures of, opp. 514.

whitneyi, figure of, opp. 514.

Ocinebra nashi, figures of, opp. 514.

Odostomia packi, 498; figure of, opp.
506.

Oligocene, The Occurrence of, in the
Contra Costa Hills of Middle
California, 9.

Oligocene of Oregon, separation of
faunas of from Lower Miocene,
10; species in common with
Agasoma gravidum zone, 19.

Ono, California, fauna at, 152.

Octatoor group of Southern India,
157.

Oregon, University of, collection of
Hipparion specimens, 6.

Oreodaphne, 414.

Oroville, California, geological map
of. 398.

Oroville South Table Mountain, list
of fauna from the Eocene of,
392.

Osborn, Il. F., acknowledgement of
assistance, 525.

Ostrea ef. appresso, figure of, opp.
510.

aviculaformis, figure of, opp. 512.

Otus asio, 100.

Owl Remains, The, from Rancho a
Brea, 97.

Pack, R. W., cited. 201, 371.

Packard, E. L., 137, 261.

Paige, Sidney, cited, 33 note 5, 34
note 7, 38.

Panpan stage of geomorvhie cycle of
the desert, 33; rarely observed
in ideal completion, 33: a phe-
nomenon to be elassified. 33.

Paskenta horizon of Knoxville beds,
138.

Pavo californicus, tarsometatarsus
90; tibiotarsus, 91; femur, 93;
humerus, 94; coracoid, 94; earpo-
metacarpus, 94.

Pavo Californicus, A Review of the
Species, 89.

Peeten coalingensis zone, 82.

Pence’s Ranch, California, 139.

Peneplain, end stage of degradation
in humid climate, 33.

Pentz (Pence’s Ranch) California,
390.

Perissolax blakei, 368.

gabbi, 497; figure of, opp. 506.

Persea, 414.

Peterson, C. G., Joh., cited, 143, note
Tale

Phacoides (myrtea) taffana, 485.

Phoenix, Oregon, type locality for
Lower Chico, 139.

Pinus, 415,

Pityoxylon, 415.

Platanus, 414.

Pliauchenia ? sp., 194; figures of,
195.

Pliocene, The, of Middle and North-
ern California, 215.

Puocene, of Middle and Northern
California, correlation of, 247;
259; fauna of, 251-258; Blanco,
of Texas, 528.

Pliohippus or Equus, 56, 79; figures
of, 57; transition between, 58;
relationship between, 525. See
also Equus.

Pliohippus coalingensis, 85.

cumminsii, figure of, 531; measure-
ments of, 534.

fairbans*i, 55; figures of, 55.

proversus, 526; figures of, 527, 529,
530. 531; measurements of, 534.

simplicidens, 56; figure of, 531;
measurements of, 534.

ef. simplicidens, figure of, 53

Point La Jolla, California, fauna of,
392

Point Loma, California, fauna of, 139.

Populus, 415.

Porter beds, 20.

Procamelus, near gracilis, 189; fig-
ures of, 191, 192, 195.

Protohippus sp., 188; figure of, 187.

tehonensis, 52; figures of, 52.
Pseudoeardium gabbi, description of,
304.

var. altum, 267; description
Oi Oils

var. elongatum, 265; deserip-
tion of, 307.

var. robustum, 265; descrip-
tion of, 307.

var. unduliferum, 265; de-
seription of, 308.

landesi, 265; description of, 309.

Purisima formation, 241; fauna of,
242, 243, 251-258.

Purpura turris, 86; figure of, opp. 88.

Index

Quarternary deposits of
Blanco, Oregon, 245,

Quercus, 414.

Rainless regions, degradation of me-
chanical disintegration, gravita-
tional transportation, wind-trans-
portation, corrasive action, 23;
slope of talus the limiting slope
of mountain facets, 24, figure of,
25; talus profile a permanent
feature of mountain fronts, 25.

Rancho La Brea, Pavo ealifornicus
of, 89; owl remains of, 97; vul-
turid raptors of, 105; eapro-
meryx material from, 111; bison
material, 124.

Reagan, A. B., cited, 282.

Recent fauna, mactroid species, in 275.

Relation of the Invertebrate to the
Vertebrate Faunal Zones of the
Jacalitos and Etchegoin Forma-
tions in the North Coalinga
Region, 7

Cape

fale

Relationship of Equus to Pliohippus
Suggested by Characters of New
Species from the Pliocene of
California, 525.

Rhinoceros hesperius, 414.

Rhinocerotidae, 180.

Rhus, 414.

Ricardo, Mohave Desert, California,
figures of type specimens from,
54, 55; Pliocene, 3, 55.

timella simplez zone, of the Cali-
fornia Tejon, 366, 374; specie in,

376.

Rocks, chemical decay (decomposi-
tion of), under humid condi-
tions, 27, due to bacterial action,
28.

Rock slopes, relation to alluvial
slopes, 26; size of fragments
from, 29; steepness, 30; over-
steeping, 30; alluviation, 30;

truncation, 31; minimum angle
for transportation, 32; panpan
and peneplain, 33, 44; subaerial
front, 31, 34, 42, rate of reces-
sion of, 35, 42, contour, 42; sub-

alluvial bench, 34, revealed as
element in visible profile by
stripping of alluvial fans, 34,

45; curved surface of, 35; con-
eave or convex, 36, determined
by acceleration of rate of rise
of the fan surface, 37, 44; nub-
bins, 38.

Rock terraces, explanation of, on
desert mountains in California,
Nevada, Arizona, New Mexico,
Mexico, 34.

Ruekman, J. H., cited, 79; acknowl-
edement of assistance, 367; cited
on white shales, 435.

[542]

Rumble Mine, near Oroville, Cali-
fornia, 390.

Sabalites, 414.

Salix, 415.

San Andreas fault, California, 201.

San Diego, California, type locality
of Lower Chico, 139; Tejon
fauna in, 437, 439.

San Francisco Basin, a negative
area in Eocene time in Califor-
nia, 467, 468, 471.

San Joaquin Valley, California, fig-
ures of type specimens from, 52.

San Lorenzo formation, 10, 11, 20;
of the Santa Cruz Quadrangle,
19; relation of Oligocene of, to
Tejon fauna, 454.

San Pablo formation, 9; mactrine
fauna of, 274, 276.

San Pedro fauna, mactroid species
in, 275.

Santa Ana Mountains, California,
Jretaceous localities in, 137;

mactrine species in, 274.
Santa Clara Valley oil district, Te-
jon strata found in, 464.
Santa Margarita formation, 201.

Santa Maria oil district, Tejon
strata found in, 464.
Santiago Cafon, California, Creta-

ceous section in, 142.

Sargent oil field, Etchegoin of, 244;
fauna of, 244, 245, 251-258; cor-
relation of, 259.

Schizodesma abscissa, 264, 289.

Schizothaerus nuttallii, 270; graph
of, 269; figures of, 360.

Scutella breweriana zone, 9.

Seattle formation, 11, 20.

Shasta County, California, relation-
ship of Chico fauna of, to Horse-
town fauna, 150; type locality
of Chieo formation, 153.

Shasta group of the California Cre-
taceous, 138.

Siderastrea clarki, 65; figures of,
opp. 74.
Sierra Nevada, geological events

alone western foothills, 416.

Silver Peak region, succession of
lavas from, 166.

Silverado Cafion, California, type
locality of Lower Chico, 139;
Chico affinities of fauna of, 150.

Simomactra, 279.

Siphonalia sutterensis, 498; figure of,
opp. 514.

Siphonalia sutterensis zone, of the
California Tejon, 366; list of
species from, 406; list of local-
ities, 408.

Snyder, J. O., cited, 172.

Speetyto ecunicularia, 104.

Index

Spiroglyphus(?) tejonensis, figure of,
opp. 506.

Spisula, first genus of Mactrinae to
appear in Pacific Coast region,
276; descriptions of, 283.

abscissa, 274; descriptions of, 289;
figures of, 336, 338.
acutirostrata, 274; description of,
295; figures of, 295; differentia-
tion from 8. merriami, 296.
alaskana, 265, 284.
alaskensis, 283.
albaria, 274, 275, 292; description
of, 290; confused with 8. planu-
lata, 291; differentiation from 8S.
selbyensis, 293; figures of, 338,
340.
ramonensis, 274, 291; description
of, 291; figures of, 336, 340.
ashburnerii, 268, 273; graph of,
269; differentiation from 8. mer-
riami, 294; description of, 298;
confused with 8. gabbiana, 299;
figures of, 342, 344.
brevirostrata, 275; description of,
296; figures of, 346.

ealistaeformis, 265, 274; deserip-
tion of, 301.
eatilliformis, 268, 274, 275, 284;

graph of, 269; descriptions of,
285; figures of, 324, 326, 328;
confused with Mactra califor-

niea, 280; with S. hemphillii,

288, with S. occidentalis, 289;

differentiation from 8S. merce-

densis, 287.

aleatrazensis, 265, 285.

chicoensis, 273; description of,

300; figures of, 344.
coalingensis, 275; description of,

301; comparison with S. breviro-
strata, S. faleata, and 8. alba-
ria, 302; figures of, 344.

dolabriformis, 264.

faleata, 275; confused with Mae-
tra dolabriformis, 279; resem-
blance to Maetra, californica
280; hinges of, compared with
those of S. planulata, 294; de-
seription of, 297; differentiation
from §S. planulata, 298; figures
of, 342.

gabbiana, 273, 298 note 24; con-
fused with S. ashburnerii, 299;
description of, 299; figures of,

344.
hemphilli, 275; descriptions of,
287; contused with S. eatilli-

formis, 288; figures of, 332, 334.

lenticularis, 274; description of,
302.

mercedensis, 275; description of,
286; differentiation from S&S.

[543]

catilliformis,
330.

merriami, 268, 274, 485; descrip-
tion of, 294; differentiation from
8. tejonensis, 303; figures of,
344, opp. 510.

montereyana, 274.

occidentalis, 274; description of,
288; confused with §S. ecatilli-
formis, 289; tigures of, 336.

planulata, 275; confused with S.
albaria, 291; deseription of, 293;
hinges of, compared with those
of S. faleata, 294; figures of,

polynyma, 283.

var. alaskana, 283.

precursor, 265, 290, 291.

selbyensis, 268, 270, 274; graph of,
269; description of, 292; differ-
entiation from S. albaria, 293;
figures of, 342.

sisquocensis, 265; description of,
302; associated with S. eatilli-
formis var. alcatrazensis, 303.

solidissima, figures of, 316.

287; figures of,

tejonensis, 274; description of,
303; figure of, 344.

truneata, description of, 300.

voyl, 275; descriptions of, 283;
figures of, 316, 318, 320.

weaveri, 274; description of, 313;
figure of, 344.

Standella california, 285.
falcata, 296; deseription of, 297.

planulata, deseription of, 290.
Stanton, T. W., acknowledement to,
138; cited, 151, 152, 156, 157,
369, 384.

Stephanophyllia californica, 66; fie-
ures of, opp. 70.
Stepovak series, Alaska,
species from, 274.

Stewart, R., 164.

Stewart Valley, Nevada, 163.

Stratigraphy and Fauna of the
Tejon Hocene of California, 363.

Strepsidura howardii, 498; figure of,
opp. 506.

Studley, C. K., cited, 153.

Suman, John R., 50.

Sumner, T. B., et al., cited, 143 note
12.

Sureula clarki, 499; figures of, opp.
514.

gesteri, 499; figure of, opp. 516.
supraplanis, figure of, opp. 506.

Sutter formation at Marysville
Buttes, deseription of, 404.

Symmorphomactra, descriptions
297.

Table Mountain, near Oroville, Cali-
fornia, geological map of, 393.

mactrine

of,

Index

Taft, J. A., acknowledgment of as-
sistance, 367; cited on Tejon
group, Cantua District, 422.

Talus, formation of, in rainless
regions, 24; profile of, a perma-
nent feature of mountain fronts,
25.

Tehachapi Mountains, Rimella_ sim-
plex zone, present in, 463.

Tehama County, California, relation-
ship of tauna of, with Horse-
town fauna, 150.

Tejon areas, columnar sections of,

456; deseription: Marysville
Buttes, Oroville, Tone, Lower
Lake, 457; Coalinga district,

459; Mount Diablo, type loecal-
ity, Santa Ana mountains, 459;
Rose Canon, 460.

Tejon Eocene of California, contact
with Agasoma gravidum beds,
12; literature cited, 368, 369,
370, footnotes; correlation, his-
torical, 475; species common to
Gulf and Pacific provinces, 476;
species Venericardia planicosta
Lamarck, stages of evolution of,
477; generic comparison of Mid-
way and Tejon faunas, 478; pro-
posed correlation, 479; new
species, description of, 481-503.

Tejon Hocene of California, Strati-
graphy and Fauna of, 363.

Tejon fauna of California, summary,
442, list of species reported,
443-453; relation of Tejon to
Martinez fauna, 455, to San
Lorenzo Oligocene, 454; sum-
mary of stratigraphy, 455.

Tejon Jills, California, figure
type specimen from, 52.

Tejon Sea, geography of, 467; maps
showing probable extent of dur-
ing certain depositional periods,
469, 470, 472.

Tejon strata between Domengine
and Cantua ereeks, list of
species collected from, 430-434.

Tejon, The, in California, four faunal

of

zones of, 366; map showing
Tejon and associated groups
south of Mount Diablo, 370;

localities of, in Coalinga quad-
rangle, 429; near Lower Lake,

441; in Santa Ana Mountains,
441.
Group south of Mount Diablo,

stratigraphy of, 371; figure of
section showing strata and asso-
ciated rocks, 372; list of species
collected from, 372 insert; fauna
of, Turbinolia zone, 373; Rimella
simplex zone, 374, 376; Balano-
phyllia variabilis zone, 375, 378.

[544]

Group north of Mount Diablo,
stratigraphy, 382; fauna, 384.

Group near Fort Tejon, strati-
graphy, 418; fauna, 418; map
showing type locality, 419; list
of species, 420.

Group, Cantua district, Coalinga
quadrangle, 422; historical, 422;
stratigraphy, 424; list of svecies
from, 425; summary of conclu-
sions, 435; white sandstone mem-
ber, fauna of, 428; white shales,
435,

Group in San Diego County, 435;
stratigraphie notes, 436; fauna,
437, 439; list of fossils in, 437;
description of Tejon Eocene lo-
cation in, 440; conclusions, 440.

Group near Domengine Ranch,
Coalinga Quadrangle, figures of
section showing strata of, 425;
fauna of white sandstone mem-
ber, 428; white shales, 435.

Tellina jollaénsis, 487; figure of, opp.
506.

Tellina, ooides zone, 142, 145, 150,
154, 159.

Tertiary provinces in the United
States west of the Wasatch
Range, outline map of, opp. 162.

Tephrocyon, figure of, 174.

kelloggi, figures of, 174.

Tertiary gravels in the Sierra Ne-
vada, schematic representation
of four principal epochs of, 412.

Tertiary Vertebrate Fauna from the
Cedar Mountain Range of West-
erm Nevada, 161.

Tebrabelodon, sp., 189;
189.

Texas Flat, California, type locality
of Lower Chico, 139.
Texas Springs, California,
fauna locality, 152.
Thamnasteria sinuata, 68; figures of,

opp. 74.

Tivela packardi, 486;
opp. 508.

trigonalis, 207; figure of, opp. 210.

Topila, Mexico, Gulf Coast, Tejon
Species from listed by Dumble,
477.

Trabuco Cafion, California, 140.

Trabuco formation, 140; conglomer-
ate character of, 155.

Transitional Oligocene-Miocene, 10.

Triassic, basement complex in Santa
Ana Mountains of Triassic age,
139.

Trichinopoli group of Southern India,
157.

Trigonoarea, 143.

Trochocyathus imperialis, 63; figures
of, opp. 72.

figures of,

Chico

figures of,

Index

oregonensis, 63; figures of, opp. 70.

pergranulatus, 64; figures of, opp.
70.
striatus, 379.
zitteli, 69.
Trophon coalingense, figures of, opp.
214.
magister, 207; figures of, opp. 214.
Truckee beds, Fossil Hill, Nevada,
164.
Tulare formation, California, 85, 532.
Tully’s Ranch, Bitterwater Creek,

San Benito County, Tejon
Eocene reported in, 464.
Turbinolia zone of the California

Tejon, 366, 373.
Turbinolia dickersoni, 61; figures of,
opp. 70.
pusillanima, 62; figures of, opp. 70.
Turner, H. W., cited, 153, 164, 369,

390, 409; description of Ione
type locality, 394.
Turonian, affinity of, with Chico

formation, 157.

Turris fresnoensis, figure of, opp. 506.
inconstans, figure of, opp. 514.
monolifera, figures of, opp. 514.
stocki, 499; figure of, opp. 516.

Turritella andersoni, 501; figures of,

opp. 516.
buwaldana, 500;
516.
kewi, 501; figure of, opp. 516.
inezana, zone, 16.
lawsoni, 502; figures of, opp. 516.
merriami, figure of, opp. 510.
nova, 208; figure of, opp. 214.
ocoyana, zone, 16.
pescaderoensis, zone, 142, 145, 150,
159.
Tusean Springs, California, type lo-
eality of Upper Chico, 139,
Twin River formation, 11, 20.
University of California, Department
of Palaeontology, work of, 162.

figures of, opp.

545]

Vader, Washington, Tejon species at,
274.

Vaqueros formation, 16, 139.

Vaughan, T. W., acknowledgment of
assistance, 61; cited, 64.

Venericardia planicosta, 368.

Venus aequilateralis, figures of, opp.
506.

Verdi, Nevada, Tertiary plants of,
167.

Vermilion Cliffs, not influenced by
climatie control, 27.

Viburnum, 414.

Volutilithes ealifornica, 368.

Vulturid Raptors, Two, from the
Pleistocene of Rancho La Brea,

105.

Wallala group of the California Cre-
taceous, 138.

Waltham Creek, California, evidence
fixing position of beds on, 200.

Waring, C. A., cited, 370, 371.

Washburne, C. W., 11.

Washington, University of, collec-
tion of mactrinae, 263.

Watts, W. L., cited, 369.

Weaver, C. E., cited, 11, 17, 19;
acknowledgment of assistance,
263.

White, C. A., cited, 138, 151, 369.

Whitney, J. D., cited, 368, 409, 462.

Wildeat series, Humboldt County,
California, 275; type locality,
234; fauna of, 237, 238, 239, 251—
258; correlation of, 259; mae-
trine species in, 275.

Woods Hole, Massachusetts, faunal
studies at, 143.

Xenophora stoeki,
opp. 506,

Young, G. J., acknowledement of as-
sistance, 162.

Zizyphus, 414.

502; figures of,

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jons on tie Mode of aeration of the Ble stocas one Deposit
fea) iy Reginald) OmstOmert. ...n. eee ge ae ace panna :
on the Horses of Rancho La Brea, by J ohn ©. Merriam ............
‘Horses from the ey of the Great ae oe by John C.

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Pleistocene Beds at Manix in the Bastern Mohave Desert Region, by 5 ohn P.
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5. he Problem of J ‘Aquatic GEES sas in the Carnivora, as Illustrated in the ae
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“a VOLUME 8.
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straciont Shark from ge Upper Triassic of Northern anion ee

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a-like Gastropods of the California Tertiary, by Walter A. English......
artinez and Tejon Eocene and Associated Formations of the Santa Ana
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Wersiam vette eee RR Bei ee iS MR. Sate act Ok i eae 2 Ye

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Dentition of the Mylodont Sloths of Rancho La Brea, by Chester Stock. 15¢
Mammal Beds of Stewart eae Tone Valleys in West-Central Nevada, by |
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1, New Species « ‘the H pparion Gr tA fr m th

inces of North America, by J John C. Merri
2, The Occurrence of Oligocene in the Contra

Bruce L. (lark ..... bh eae ne
3. The Epigene Profiles | sert, by | ew C. Lawson .........-.
4, New Horses from the Miocene and Pliocene of California, by a oh
5. Corals from the eh and Tertiary of California and Oreg<

Nomlamd? .Sytst0 0.3... ae oto IE UR ae ae nay a
' 6. Relations of the Invertebrate nf the Vertebrate Daan Zones of th
Etchegoin }'ormations in the North Coalinga Region, California
i) Nomland
iY \\iae A Review of the Species Pavo aaforiions, by Loye Holmes Miller |
'8. The Owl Remains from Rancho La Brea, by Loye Holmes Miller ...
9. Two Vulturid Raptors he bi Pleistocene ot baaltcck La Brea,
MMT r: 2. Me Be UE I de a oa ae

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(CRam der: eee eee a ee eee ee ae dub 9 EURO ea Pe See oe ea.
il, A Study of the Skull and Dentition of Bison antiquus Leidy, with Sp
to Material fromthe Pacific Coast, by Asa C. Chandler
12, Faunal Studies in the Cretaceous of the Santa Ana Mountains of eels
forma, by Marl Deroy Baciard 327.0012)... Sees See sees
13, Tertiary Vertebrate Fauna from the Cedar Mountain Region of Western 1 Teva
Pe dObn \O, WMerrkamay ye ae eee cots ede RNR a i ee ae aa
14, Fauna from the Lower Pliocene at Jacalitos Creek and Waltham ET dite
County, California, by Jorgen O. Nomland qn... -----ncpeeeesenenesnennenee-taneen seetonns
, (15, 16, and 17 in press.) }
18: Relationship of Equus to Pliohippus Suggested by Characters of a sor
from the Pliocene of California, by John C, Merriam

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