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UNIVERSITY OF CALIFORNIA PUBLICATIONS

/
ae IN
c 2 5

GEOLOGY

ANDREW C. LAWSON
JOHN C. MERRIAM

EDITORS

VOLUME VII

WITH 25 PLATES

UNIVERSITY OF CALIFORNIA PRESS
BERKELEY
1912-1914

rT
“ad aian

£S VBR SAY

Inetii, >
7,

‘a,

. 20.

eis

CONTENTS

The Minerals of Tonopah, Nevada, by Arthur 8. Hakle — 2...

Pseudostratification in Santa Barbara County, California, by George
WD avSwlbOUGIeT bac Ke mie, ces eetas see ec cacee soe oa sac cns nny Saeeseo te cours seu ee

Recent Discoveries of Carnivora in the Pleistocene of Rancho La

Brea, by John ©. Mierriann ..222occcccc2c2ccs sa cesca cece stceecs, eeccctectecceseesectenersene
The Neocene Section at Kirker Pass on the North Side of Mount
Dilablomiby Bruce: Uris Clear yee cee cece sae ce ss seen osc eeee en seen eee cee ee eee
Contributions to Avian Palaeontology from the Pacific Coast Region
of North America, by Loye Holmes Miller ...........20.220.20...2022--220----
Physiography and Structure of the Western El Paso Range and
the Southern Sierra Nevada, by Charles Laurence Baker ..........
Fauna from the Type Loeality of the Monterey Series in Cali-
fornia, by Bruce Martin .......... Bere soeeee Seen! 2 at Oe OB See ee
Pleistocene Rodents of California, o Louise Kellogg ............2...22

Tapir Remains from the Late Cenozoic Beds of the Pacifie Coast
Inexeationat, Joye collin (Ol, Wilpewevinis haa) eee ree ee ere eee ee
The Monterey Series in California, by George Davis Louderback ..
Supplementary Notes on Fossil Sharks, by David Starr Jordan and
ROP BEE MOS Bs) Wale eY2 Ue eee sn ee er ere red Ain
Fauna of the Eocene at Marysville Buttes, California, by Roy E.

DCR EES Ocean ee entre sais teas ete re eee OOS Nee CLA n ees oe ee eed y

Notes on Scutella norrisi and Scutaster andersoni, by Robert W.

L2G eee ee orate te EES oh eRe LO y

The Skull and Dentition of a Camel from fhe Pleistocene of Rancho
WGambneas bison (C2 Mierruenm) 22 cesseececcec-csecees eeeec cesses eceecene sees .
The Petrographie Designation of Alluvial Fan Formations, by
PST T Give © sumer, OI eee steak tas awe ee ane os Mears te ore orien nee
A Peculiar Horn or Antler from the Mohave Miocene of Cali-
aeOHeADEN,, |oie Ifoaual (Of MUS yesamles al, erry ere eee es ee ger eens ee

Nothrotherium and Megalonyx from the Pleistocene of Southern

@alhtommiareibweCHeESterm S00 Clay sess cce- oe eccseceeeeeet setcseeee sec -eeeeeesee ee |

Notes on the Canid Genus Tephrocyon, by John C. Merriam .......... ‘

Vertebrate Fauna of the Orindan and Siestan Beds in Middle

C@anliionmnid apm ivare) (0 ines © sme [e ty Tineesneee ce eseeenees tates ceeeeee wees eee ere es eeee ‘

Recent Observations on the Mode of Accumulation of the Pleistocene

Bone Deposits of Rancho La Brea, by Reginald C. Stoner —...... 3

Preliminary Report on the Horses of Rancho La Brea, by John
ree Vile Ter cin eee rte oe ares, Aosta De a el 2a ae ees eee eee

No. 25.

New Anchitheriine Horses from the Tertiary of the Great Basin
Area, by: John ©), Merriam. _......
New Protohippine Horses from Tertiary Beds on the Western
Border of the Mohave Desert, by John C. Merriam ....................
Pleistocene Beds at Manix in the Eastern Mohave Desert Region, —
by John Ps Buwalda. .....2...3 2 ee
The Problem of Aquatic Adaptation in the Carnivora, as Illus-
trated in the Osteology and Evolution of the Sea-Otter, by
Walter P. Taylor 22...

OF CALIFORNIA PUBLICATIONS 2 |
fag LETIN OF THE DEPARTMENT OF oe
Pe GEOLOGY |

a 3 is

0. 1, pp. 1-20, pls. 1-2 Issued May 17, 1912
Ber Ne ee ee ba aise oS

NS Bra "
ARTHUR S. EAKLE

__ UNIVERSITY OF CALIFORNIA PRESS
at es ee BERKELEY — pres:

“ee

‘ i

Sa A okesnk or the: 1S
be ee and Ethnolo ital Nee se
| Education, Modern Phaplogy, eiloeeia
[sy _ Psychology. "a

ances. —Anprew C. Lawson and. Joun C. Apc Baitor

Volumes 1 (pp. 435), II (pp. 450), IIL (pp. 475), IV (p pe
bi completed. Volume VI {in progress).

Cited as Univ. Calif. Eup. Bull. Dept. G

Vol. 1, 1893- 1896, 435 pp., with 18 platen, price $3. 50, Bis, tise.
this volume will be sent on request.

f Nhe yee
- . $

VOLUME 2.

1. The Geology of Point Sal, by Harold W. Fairbanks...
2. On Some Pliocene Ostracoda from near Berkeley, by Fr
3. Note on Two Tertiary Faunas from the Rocks of the So

Island, by J. C. Merriam sae ere re Bae

4. The Distribution of the Neocene Sea-urchins of Middle
a on the Classification of the Neocene Formati
_ 5. The Geology of Point Reyes Peninsula, by
_ 6. Some Aspects of Erosion in Relation to
ai, niearici ers Smiithh, oc. Pees se 0 at ed ene. peer ee NN
_ 7. A Topographie Study of the Islands Ge ar Gest pee nae
| 8. The Geology of the Central Portion of the Isthmus of Panama, b
9. A Contribution to the Geology of the John Day Basin, by John
10. Mineralogical Notes, by Arthur S. Hakle....s.ccccccccccccccecccecesee
‘11. Contributions to the Mineralogy of California, by Walter C. B
12. The Berkeley Hills. A Detail of Coast Range Grploe yy by Andr
__.~ @harles Palache ........ Lee Ae eee Ee iets Aan eee

wen earner ean en nee ween ee nen n ee anew enna:

vi la oe “VOLUME. Chats ;
bane © The Quaternary of Southern California, by Osear Hs Hershey
_ 2. Colemanite from Southern California, by Arthur S. Eak
8. The Eparchaean Interval. A Criticism of the use of Be term 4
- Andrew C. Lawson
. Triassic Ichthyopterygia from California ‘and vada, bys
. The Igneous Rocks near Pajaro, by John A. Rei
. Minerals from Leona Heights, Alameda Co., California, h
peeormnasttes an Oligoclase-Corundum Rock, near oo
pAndrew9G. (lawson (2...) ee 2 re
~ 9. Palacheite, by Arthur S. Eakl
10. Two New Species of Fossil Turtles from Oregon, by 0. -
TA: A New Tortoise from the Auriferous Gravels of Califor:
- . Nos. 10 and 11 in one cover........
12. New Ichthyosauria from the Upper Tring ¢ of Ca.
13. Spodumene from San Diego County, California, by Wal
14. The Pliocene and Quaternary pease et the Great
: Jahn Gy. Merriam’ <).:..: Sees eae S:
15. The Geomorphogeny of the Upp r
16. A Note on the Fauna of the Lowe Miocene
¢ 17. The Orbicular Gabbro at Dehesa,
Se slot yippee oes seater oe eae
‘ 18. A New Geatraciony ‘Spine from 2
eae Fossil Egg from Arizona, b} Wm. Cong
, 20. Euecratherium, a New Ungulate from the
iliam J. Sinclair and ‘E. L, Furlong.......
1, A New Marine Reptile from the Triassic of Californ
2 Bane River ort 0 of the Deleeas Basin, Gaus rn

pS ry RO

ween nw eee ne nnn en nen nnn eee ee, eo wennne

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 1, pp. 1-20, pls. 1-2 ‘ Issued May 17, 1912

THE MINERALS OF TONOPAH, NEVADA

BY
ARTHUR S. EAKLE

CONTENTS

: PAGE
Genesishotethe minerals 2.025 2.22 s sg lessccseeesecectebicsstdccenensotstnseeres ieegectecscszaccunee 1
Onigimwotathen deposits: 222 ..2.cscss.2-<eeesececeeeenctenscoevsencecteneeeeceeeepceeesees ateverscecss 2
Oxidation of the: Veins: ....--.--------2--s-teeesceearoccsestseacccescbcdsecceszecseatssesvaesseetee 2
@rigamyot they silver, hallows! :2-.-- cece eee sestecre cer eecceeccencsecensares 3
The hydrous secondary minerals .............--.-.-:-:e:c:cececceeceeeeeeeeeeeeteeeees 6
Weseniptionsof the: mineral st... 2 2: csc.lescc.sccsetecesessecsceysestesdtsnesceenastoeteeeesseecaences i
Native Elements: Gold and Silver ...........200.2.0200-. 0 ---cesceeeeeceeeeeeeeeeeeeees 7

Sulphides: Argentite, Galena, Cinnabar, Pyrite, Chaleopyrite, and

ESO Se rR eC 7
Sulphantimonites: Polybasite, Stephanite, Pyrargyrite, and Tetra-

WO GG Cy 2 re snes Sete s aassencctey tse ic ave eecteat ew actuescedeqacsiceevseesesiisdsiseestcaaceefase0ess22 8
Haloids: Cerargerite, Embolite, and lodyrite —.........-.-.--------ee ,
Oxides: Quartz, Opal, Cuprite, Hematite, Limonite, Manganite,

iPyrolusite, Psilomelane, and! Wad) -2-2----------------------2o--2oc-eseeetececscetese= 13
Carbonates: Calcite, Manganocalcite, Rhodochrosite, Malachite,

UII ePAUZ TUL Cig re Set ME eee 1 cds baseestereetaes ea everes ast deestavetsscecssodssoutas oiabeetar 14
Silicates: Feldspar, Kaolinite, Sericite, and Rhodonite —............... 15
Phosphates and Arsenates:. Apatite, Pseudomalachite, Wavellite,

Turquois, Pharmacosiderite, and Cacoxenite ............--.-----.----- 16
Sulphates: Gypsum, Jarosite, and Barite -......-....0..20200220--2---eeee ee qi

Tungstate and Molybdate: Hiibnerite, or Wolframite, and Wulfenite... 18

GENESIS OF THE MINERALS

Some of the minerals occurring with the silver deposit at
Tonapah were mentioned by Spurr’ in his paper on the geology
of the district, and by Burgess? in his discussion of the origin of

1 Spurr, J. E., Geology of the Tonopah Mining District, Nevada, U 5S.
Geol. Surv., Prof. paper no. 42, 1903.

2 Burgess, J. A., The Halogen Salts of Silver and Associated Minerals
at Tonopah, Nevada, Econ. Geol., vol. 6, p. 18, 1911.

University of California Publications in Geology. (Vou. 7

the silver haloids. The latter author collected a good suite of the
minerals found in the veins and sent them to the writer for
further study and report, and it is from a study of this material
that the following notes on the minerals have been prepared.
Origin of the deposits —The silver deposits occur in a trachyte
9?

and were
formed by ascending solutions carrying the sulphides and the

which Spurr first designated as ‘‘earlier andesite,

gold and depositing them at a period immediately following the
eruption. The typical ore consists of a gangue of massive white
quartz and white feldspar containing blotches and bands of
finely granular, black silver minerals, small amounts of pyrite,
chalcopyrite, galena, and sphalerite, and occasionally free gold.
The dark silver bands are mainly argentite, with which are
intimately mixed polybasite and perhaps stephanite and tetra-
hedrite. An analysis of the primary sulphide concentrates of
the Montana-Tonopah mine, made by Hillebrand and quoted by
Spurr, indicates that the simple sulphide, argentite, predom-
inates, but has probably mixed with it small amounts of silver
sulphantimonites and sulpharsenites and some selenide of silver,
or of lead and silver. These sulphide minerals are all primary
constituents of the veins, yet most if not all of them also occur
secondary, and some of the crystals in the cavities of the gangue
are doubtless of a later generation.

Oxidation of the veins—The deposits at Tonopah lie in an
arid region and, like most desert deposits of sulphide minerals,
have their oxidized zones characterized by a variety of rare sec-
ondary minerals not found where simple hydration only is pos-
sible. This is due to the fact that surface waters penetrating to
the vein matter below and bringing about its alteration become
charged with salts leached from the overlying and adjacent
strata, and complex oxidation with less usual mineral precipita-
tions result. The descending solutions which brought about the
main oxidation of the silver minerals at Tonopah contained the
alkali bromide and iodide as well as the much more abundant
chloride, and the complexity of the depositing solutions is evi-
denced by the coatings of haloids, phosphates, arsenates, man-
ganates, and sulphates which line the walls of fissures and cavities
in the gangue.

1912] Eakle: The Minerals of Tonopah, Nevada 3

The origin of the silver haloids—The most important second-
ary minerals in the zone of oxidation are the three silver salts,
cerargerite, embolite, and iodyrite. They have undoubtedly
erystallized out of descending solutions which obtained their
chlorides, bromides, and iodides from superficial deposits im-
pregnated with the alkaline salts, and their general arrangement,
as stated by Burgess, is in three zones with cerargerite above,
embolite intermediate, and iodyrite below. Since iodyrite is much
less soluble in water than cerargerite, this order of crystallization
may appear reversed, but in reality it is the natural order of
occurrence when the silver salts have been deposited from mixed
solutions such as undoubtedly obtained at Tonopah.

The formation of good erystals of these difficultly soluble salts
generally indicates a slow growth by gradual evaporation of very
weak solutions, but the degree of solubility and of concentration
before crystallization depends upon the solvent, and erystals may
not form until the excess of certain salts have first been removed.

In the cerargerite zone the crystals are quite perfectly formed
and have evidently grown from solutions dilute enough to pre-
vent the previous precipitation of manganese and iron hydrates.
While the oxides of iron and manganese may be abundant in
this zone, their formation from the solutions was independent of,
and later than, the formation of the cerargerite.

In the embolite zone the erystals are in general imperfectly °
formed and segregated into bunches. They characteristically
rest upon coatings of psilomelane and limonite which have been
previously deposited from the solutions and therefore indicate a
growth from more concentrated solutions.

In the iodyrite zone the imperfectly formed crystals have
grown rather rapidly from solutions concentrated sufficiently to
precipitate previously psilomelane, flaky hematite and flaky
jarosite in abundant coatings and masses. The evidence points
strongly to the conclusion that the crystallization of the iodyrite
depended upon the prior or simultaneous precipitation of these
iron and manganese minerals.

It is manifestly impossible to form more than an approximate
idea of the character of the oxidizing solutions. The waters con-
tained essentially chlorides, bromides, iodides, carbonates, and

4 University of California Publications in Geology. (Vou. 7

sulphates of the alkalies, leached from the surface material and,
acting on the abundant pyrite and manganese minerals of the
rocks, they became charged with iron and manganese salts.
Probably more or less free acid and free gas were formed in the
mixed solutions, and the decomposing and oxidizing effect of
these solutions on the sulphides of the veins and on the gangue
must have been comparatively rapid. The solutions which
percolated downward through the ore body were essentially
sulphated waters of the alkalies, iron, manganese, and silver, with
potassium and sodium chlorides, bromides, and iodides.

The alkali chlorides predominated over the bromides and
iodides in the upper zone of oxidation and it is safe to say that
chlorine was greatly in excess of bromine or iodine in this zone.
The dilute solutions moved slowly downward through main
channels and narrow fissures, thoroughly saturating portions of
the vein, leaching out the potash of the feldspar and converting
the silver sulphides to sulphates. With sufficient silver present
the evaporation in this zone would have caused the precipitation
of the main deposit of the cerargerite even if the bromide and
iodide of silver had also been thrown out previously or with it.
These two haloids, however, would not have existed in the alkali
chloride solution but would have been completely transposed
into cerargerite, while the bromine and iodine would have been
absorbed in the cold solutions and carried down possibly as
sodium and potassium salts.

The solutions passing downward became more concentrated
in bulk, stronger relatively in bromine, iodine, and alkalies, and
at the same time depleted in chlorides, until a stage was reached
where the almost constant associate and natural successor of
cerargerite, the double salt embolite, crystallized. Bromine and
chlorine are alike and usually accompany and replace each other,
so that cerargerite and embolite are typically associated. As the
chlorine diminished in the solutions, bromine replaced it in
cerargerite as shown by tests, and probably a gradation from
cerargerite to embolite occurs in the mines. The embolite zone
represents a proportionate increase of bromine to chlorine in the
solutions, yet sufficient chlorine was still present to prevent the
formation of bromyrite and to form considerable cerargerite in

1912] Eakle: The Minerals of Tonopah, Nevada 5

this zone and some in the lower zone. The embolite is typically
deposited in bunches of imperfect crystals on layers of psilo-
melane, and the occurrence suggests the possibility that the
bromide was soluble in the excess of the alkali-manganese sul-
phates and could not form readily as embolite until some of the
sodium and potash was removed with the manganese by evapora-
tion. No analyses have been made of the manganese oxides, but
doubtless they contain considerable potash and sodium, since
these two alkalies were abundant in the solutions. It is well
known that the silver haloids are soluble in the alkali chlorides,
bromides, and iodides, the alkali carbonates, and probably in the
alkali sulphates, so that the general tendency of alkaline solu-
tions is to dissolve the silver salts. Cerargerite crystallized in
the upper zones because of the prodominance of chlorine in
dilute solutions of the alkalies, although the solubility of the
chloride was raised; but in the embolite zone the solutions had
become more concentrated and at the same time considerably
stronger in the alkalies, especially potash from the leaching of
the orthoclase, and neither the cerargerite, the iodyrite, nor the
embolite of this zone erystallized until the hydrate of manganese
was thrown down, carrying the restraining alkalis.

The solutions percolating downward carried small amounts
of chlorine and bromine and most of the iodine in the form of
alkali salts of these elements. They also contained large amounts
of potassium, iron, and manganese derived from the veins, and
in the final evaporation of the waters, abundant coatings of
psilomelane, flaky precipitated hematite and platy crystals of
jarosite were formed. The wobbly erystals of iodyrite and
smaller bunches of embolite are in general perched upon these
coatings or crystallized with them, and the evidence seems con-
clusive that the iodyrite was soluble in the concentrated solutions
and did not erystallize until after the hydrates of iron and of
manganese had been precipitated or had begun to form. What
kept the iodyrite from forming was probably the strong solu-
tions of potassium and sodium sulphates, and it was not until
the alkalies had been removed in the formation of the jarosite
and psilomelane that the silver iodide could crystallize. Iodyrite
is decomposed by strong solutions of potassium or sodium sul-

6 University of California Publications in Geology. [Vou.7

phate and also slowly by ferric sulphate and presumably by
manganic sulphate, so its solubility may have been due to a
combination of these salts.

The three zones probably represent the action of long stand-
ing solutions on the silver minerals of each zone and what silver
was carried below was in the form of silver sulphate and not as
haloids. The bromine and iodine were presumably carried down
as alkali salts. The oxidation of the deposit may have been long
continuous or at successive intervals, but it seems to the writer
that a basin must have formerly existed above the deposit in
which the salts accumulated, and that a body of water from this
basin penetrated to the ore below carrying these salts.

In the passage of the solutions downward pools were doubtless
formed in the ore body, which gave rise to rich pockets of the
haloids. The occurrence of some of the iodyrite crystals sug-
gests also that they were formed by fumes of free iodine acting
on the silver. Doubtless free iodine was formed by the decom-
position of the iodide or iodate in the concentrated hot solutions,
and it must have formed if free acid was present.

The hydrous secondary minerals —The secondary minerals
derived by the alteration of the metallic and basic constituents
of the deposits are characteristically present in the form of coat-
ings on the walls of cavities and fissures. The coatings are
either in very thin, minutely crystalline, drusy layers or they
form minute botryoidal groupings. Most of them are brilliantly
lustrous but the crystals are generally unmeasurable.

The hydrous manganese oxide is present in soft velvety layers
of impure material and in hard mammillary shells of psilomelane.
Much of it may have been derived from the alteration of man-
ganese tungstate which appears to be one of the older minerals
of the vein. Manganese hydroxides carrying the alkalies un-
doubtedly played an important part in the formation and erystal-
lization of the silver haloids and in its association with these it
was, in general, deposited first and forms the layers upon which
the crystals rest.

The soluble phosphate, arsenate, and sulphate occur in the
lower or iodyrite zone of oxidation. They have necessarily been
erystallized from more concentrated solutions, while at the same
time they antedate the formation of much of the iodyrite.

1912] Eakle: The Minerals of Tonopah, Nevada 7

The few carbonates are of probably more recent formation
than those minerals derived by the general oxidation of the
deposit.

DESCRIPTION OF THE MINERALS

NATIVE ELEMENTS: GOLD AND SILVER

Gold.—Free gold occurs as small flakes and grains in the
narrow black bands of argentite, on the borders of small, irregu-
lar veins and seams of quartz, mostly in the vicinity of the
Valley View vein. Arborescent groupings of deformed octa-
hedrons and rhombic dodecahedrons have occasionally been
found in some of the mines. Gold oceurs in very limited quanti-
ties in rich silver ore, the general ratio of gold to silver being
about 1 to 90. The metal appears to have been deposited
originally with the silver minerals, either as visible particles
or later made visible through the decomposition of the silver
minerals containing it. No tellurides have been found in the dis-
trict and no traces of tellurium in the concentrates, but its near
relation selenium is present in over two per cent, as shown by
Hillebrand’s analysis. It is probably a constituent of polybasite
or tetrahedrite, or forms a silver selenide rather than a gold
selenide.

Silver.—Wires, films, and spongy masses of metallic silver are
frequently found accompanying the various silver minerals,
especially in the vugs where these are better crystallized. The
wires are generally attached to argentite, polybasite, tetrahedrite,
or pyrargyrite, and the metal is evidently a reduction product.
Some of the polybasite crystals have their surfaces honeycombed
and the small cellular cavities filled with minute capillary silver.
Wire silver is prominent in the Belmont mine and one quartz
specimen from the 1000-foot level charged with platy tetra-
hedrite has a fine wire coating.

SULPHIDES: ARGENTITE, GALENA, CINNABAR, PYRITE,
CHALCOPYRITE AND SPHALERITE
Argentite.—The chief mineral of the Tonopah veins is argen-
tite, but the sulphide is intermixed with the sulphosalt, poly-
basite, and possibly stephanite. The mineral is both primary and

8 University of California Publications in Geology. ([Vou.7

secondary and the better crystallized masses in the gangue vugs
are probably largely secondary. The common reticulated and
arborescent shapes occasionally show the octahedron or cubo-
octahedron, very must distorted.

Galena.—Rich sulphide ore containing a high percentage of
gold often has galena disseminated through it accompanied by
pyrite and chalcopyrite. Galena is found at all depths, and in
the lower workings of some of the barren or low-grade veins it
is associated with sphalerite and chalcopyrite.

Cinnabar.—Minute patches and thin streaks of the red mer-
cury sulphide are visible in some of the gangue of the West End
mine. The mineral is very scarce in the veins and has only been
observed in this mine.

Pyrite—The country rock and wall rock of the deposits con-
tain much pyrite, but its scarcity in the vein-matter has been
commented upon by Spurr. It is held to be largely secondary,
but some of that is undoubtedly primary which is so intimately
associated with the fine granular black silver bands. Many of
the crystals of polybasite when broken show small particles of
pyrite and chalcopyrite as inclusions.

Chalcopyrite—Limited amounts of chalcopyrite are seen in
all parts of the veins, usually in very fine grains, and it is a
common inclusion in the polybasite crystals. It is the source of
the few secondary copper salts in the oxide zone.

Sphalerite—Brown sphalerite is very limited in its occur-
rence in the veins. It is found with galena, chalcopyrite, and
traces of silver, below the 900-foot level of the Mizpah shaft.

SULPHANTIMONITES: POLYBASITE, STEPHANITE?, PYRARGYRITE,
AND TETRAHEDRITE

Polybasite-——The brittle black sulphantimonite of silver,
accompanying the argentite as one of the primary minerals of
the veins, is chiefly polybasite. Platy crystals occur in the quartz
cavities and seams, some of them with very brilliant faces. When
broken they show a characteristic cherry-red color like pyrar-
eyrite. The erystals are thin basal plates with their edge-faces
horizontally striated, and they consist mainly of a broad base
with narrow faces of the pyramid p (111), the prism m (110),

1912] Eakle: The Minerals of Tonopah, Nevada )

and the brachypinacoid 6 (010). A few erystals had in addition
the form r (112), and one showed a good face of a new form
o (443). The typical habit of the crystals is seen in figure 1,
plate 1.

Measured Caleulated
(110) : (110) » 60°08’ 60°10’
(110) : (010) 30 00 29 5d
(001) : (111) 61 15 61 14
(001) : (112) 42 14 42 19
(001) : (443) 67 46 67 38

Stephanite——Whether stephanite is mixed with the polybasite
in the black silver bands is practically impossible to determine.
All of the erystals of the brittle black silver occurring in the
cavities of the specimens examined are polybasite, so the pres-
ence of stephanite was not proved.

Pyrargyrite—The dark ruby silver is generally found as a
fissure-filling in the quartz, often intergrown with argentite and
polybasite, and accompanied by wires of native silver. Most of
the mineral appears granular in the quartz, in the characteristic
dark gray bands with reddish cast. Small dark-red crystals have
been formed in some of the cavities, consisting of the simple com-
bination of second order prism a (1120), base ec (0001), and
rhombohedron r (1071).

Measured Calculated
(2110) : (1120) 60°02’ 60°00’
(0001) : (1011) 42 18 42 28

Tetrahedrite—Thick tabular plates of tetrahedrite in the
gangue of quartz and feldspar, with wires of native silver, occur
in a specimen from the Belmont mine.

HaAoips: CERARGERITE, EMBOLITE, AND JODYRITE

Cerargerite—The chloride of silver is the most abundant
member of the haloids in the deposits. It occurs throughout the
zone of oxidation, but is principally found in the upper portion
of the zone. Waxy coatings of the mineral cover several square
feet in area and minute crystals are abundantly disseminated in
the soft kaolinized feldspar, and in the small cavities of the
quartz. The coatings and crystals have a very brilhant adaman-
tine to waxy luster, and most are of a translucent pale gray color.

10 University of California Publications in Geology. [Vou.7

Some coatings incline toward a green color and seem to grade
into embolite. The erystals are very minute in size and form
perfect cubes with generally the octahedron. Some are distorted
into prismatic shapes and others are twisted and curved and
show evidences of having been formed from dripping solutions.

Spurr® cites the occurrence of cerargerite as an inclusion in
primary argentite and advances the possibility of the formation
of the hornsilver by the solvent action of the same solutions which
deposited the original sulphides. It is possible and even probable
that some chlorine was present in the original ascending solutions
and that some cerargerite may have been formed, but it appears
undoubted that surface waters brought in the bulk of the chloride
and accomplished the main oxidation of the deposit.

Embolite-—The chloro-bromide is not so abundant as the
simple chloride or iodide, and it is chiefly found intermediate
between the two. It occurs in bunches and groups of green,
imperfectly formed crystals, often implanted on psilomelane.
The erystals are highly deformed cubes and octahedrons, with
sometimes the rhombic dodecahedron.

In the crystallization of the cerargerite considerable bromine
was taken up, so the amount of embolite present in the mines does
not represent the original quantity of bromine carried in the
solutions.

Todyrite—Bromine so generally accompanies chlorine that
embolite is a characteristic associate of cerargerite in deposits
containing important amounts of the latter. Iodine on the other
hand is very rare, and the Tonopah deposit is quite exceptional
in having iodyrite in a comparatively large quantity. The iodide
is mostly confined to the lower depths of the oxidized zone. It is
present as small loose erystals in the cavities and fissures of the
veins, and as brilliant crystalline crusts and coatings on the walls
of fissures. One of the largest pockets of loose crystals was
found in the Valley View vein, a few feet above the 500-foot
level. It contained a host of deep yellow erystals mixed with
small fragments of stalactitie and conchoidal psilomelane. The
crystals also occur characteristically with flaky brown and yellow

3 Loc. cit.

1912] Eakle: The Minerals of Tonopah, Nevada ali

jarosite. The later crystallization of the iodyrite is evidenced by
its deposition on layers of the iron sulphate and on other second-
ary minerals lining the fissures.

The crystals are mainly of a bright sulphur-yellow color, but
some incline to greenish yellow, and others are tarnished bronze-
brown. The brilliant crystals after exposure to light gradually
become cloudy and opaque. The best crystals for measurement
occur isolated in quartz cavities, generally perched on drusy
quartz.

Todyrite possesses considerable crystallographic importance
because it is one of the few known representatives of the
dihexagonal-pyramidal, or hemimorphoric, class of symmetry,
and many of the Tonopah crystals show this hemimorphic char-
acter quite prominently. With very few exceptions the crystals
are simple combinations of the unit prism (1010), base (0001),
and steep pyramid (2021). The prism is terminated on the
upper or positive end, according to the usual orientation, by
narrow faces of (2021) and a broad base, and on the lower or
negative end by (2021), often without a lower base, as a char-
acteristic habit. The few other forms are very rare and were
observed only once or twice in a lot of several hundred crystals
examined. Leaving out all doubtful forms, which were many
on account of imperfections, the forms determined were :

c (0001) i (2021) u (4041)
m (1010) r (1011) a (2027)
a (1120) f (3031) c (0001)

One crystal showed narrow faces of the second order prism
(1120). Several had the unit pyramid (1011) as very narrow
faces. The steeper pyramids (3031) and (4041) were each
observed on two erystals. The only negative pyramidal termi-
nation was (2021).

The four forms (0001), (1010), (2021), and (2021) make
up the erystals and the habit or type is governed by the size and
predominance of these forms. Few of the crystals are simple
because of the alternating growth of prism and pyramid. Sue-
cessive alternations of these two forms have produced hori-
zontally striated, furrowed, stepped, and tapered crystals
which make measurements very poor. <A fact also observed was

12 University of California Publications in Geology. [Vou.7

that the alternations were not rigidly parallel in many cases,
and that even the interfacial angles were sometimes distorted.
One of the best crystals which gave sharp signals measured
(0001) : (2021) = 58° 43’ and (0001) : (2021) —64° 12”, wath
angles lying between these for the adjacent readings. Similar
variations were noticed on other crystals, and it seems probable
that the oscillations in the growth, combined with a slight sec-
tility of the mineral, have caused a deformation of the angles.
Some of the prisms have their negative ends terminated by good
faces of the steep pyramid and small base, but the lower end
is rather characteristically drawn out into a long, wobbly and
curved, tapering pyramid. Many of the crystals, especially the
larger ones, are mere shells or hollow prisms with irregular
cavities.

The imperfect character of most of the crystals renders good
measurements impossible, and readings were obtained which
correspond to various new and improbable forms. These erystals
have been described by Kraus and Cook,* who give several new
forms. From the nature of the crystals these new forms would
need to be substantiated by further observations of them. As
shown above, considerable variation in the angle between the
base and pyramid may exist and their forms (7074), (7073),
and (15.0.15.8) seem to be striated gradations into, or imperfect
readings of, the form (2021). The angle (0001) : (2021) =
62° 10’, and their angles for these forms show a variation of
—3° 23’ to + 3° 23’, as seen from their measurements :

(0001) : (7074) = 58°47’

(0001) : (7073) = 65 33

(00010) : (15.0.15.8) = 60 32

With good erystals there might be no question about the validity
of these new forms, but on the Tonopah crystals their existence
is very doubtful. Their new form (9092) may be the known
form (4041). The angle (0001): (4041) is 75°12’ and the
writer obtained measurements varying from 74° 55’ to 76° 40’
for a form which is probably (4041), although the latter angle
yields more closely the indices (9092).

4 Kraus and Cook, Iodyrite from Tonopah, Nevada, Amer. Journ. Sci.,
vol. 27, p. 210, 1909.

1912 | Eakle: The Minerals of Tonopah, Nevada aL}

The best readings obtained for the several forms observed
gave as averages:

Measured Caleulated
(0001) : (1011) 43°27! 43°25!
(0001) : (2021) 62 13 62 09
(0001) : (3031) 70 31 70 36
(0001) : (4041) 75 52 75 12
(1010) : (1120) 30 00 30 00

Twinning is on the usual twinning-plane (3034), but not many
of the crystals are twinned, comparatively. The twinned erys-
tals are generally flattened parallel to the prism faces in the
same zone with the twinning-plane.

Some of the characteristic types of the erystals are illustrated
in figures 2 and 3 of plate 1.

OxIDES: QuaRTz, OpaL, CupritE, Hematire, LImMonire, MAN-
GANITE, PYROLUSITE, PSILOMELANE, AND WAD

Quarte.—Massive white quartz constitutes the chief part of
the gangue. The fine granular silver minerals are always in it,
and the best of the crystals occur in its cavities and fissures.
Many of the cavities of the veins have been produced by the
alteration and leaching out of the feldspathic portion of the
gangue, and these pockets are often lined with a secondary
deposit of drusy quartz and quartz crystals, which are sometimes
corroded and stained yellowish brown. Trigonal development
of the quartz terminations are common, but none occur with
trapezohedrons.

Opal.—In the Valley View vein a small amount of clear
colloidal silica has solidified into colorless hyalite and this has
spread as a thin coating over minute crystals of white apatite,
giving them a glassy glaze. The opal has taken up crystals of
yellow iodyrite and other fragments in its flow and it is one of
the latest secondary formations.

Cuprite—A few small masses of the red copper oxide have
been encountered in the oxidized zone, which have their source
originally in the chaleopyrite.

Hematite and Limonite—Naturally the common iron oxides
would be plentiful in the weathered zone as impure earthy

14 University of California Publications in Geology. [Vou.7

masses and stains, from the decomposition of the pyrite and
wolframite and former iron-bearing minerals. Dark-red earthy
masses with seams of brown jarosite are found in association
with the iodyrite. The yellowish stains of limonite color much
of the quartz, especially in those cavities and crevices where the
fibrous cacoxenite occurs.

Manganite, Pyrolusite, Psilomelane, and Wad.—The black
oxides of manganese are very abundant in the zone of oxidation,
and their close association with the several silver haloids is
significant of their influence in the crystallization of the latter.
Manganite is present in some of the pockets as long, slender,
vertically striated rods. Pyrolusite is finely fibrous and forms
coatings along the walls of some of the fissures. <A felty variety
is seen on some of the specimens. Psilomelane is the common
manganese mineral of the mines. It is generally in_botry-
oidal and small mammillary masses, and the embolite and
iodyrite are often deposited on them. Some of the pockets of
the gangue contain broken fragments of psilomelane mixed with
loose erystals of iodyrite. Manganese is present also in soft,
velvety coatings, with quite impure mixtures, and may be
classed as wad. Brown jarosite crystals are generally implanted

on such black coatings.

CARBONATES: CALCITE, MANGANOCALCITE, SIDERITE, RHODOCHRO-

SITE, MALACHITE, AND AZURITE

Calcite-—The carbonates in the mines are all of later second-
ary origin. Some good ealcites line the crevices near the 200-
foot level of the Mizpah vein. They rest upon fibrous malachite
and some are bright green from inclusions of the copper car-
bonate and some have a coating of colorless gypsum. The
crystals show an unusual habit. They are steep rhombohedral
with curved faces, and the rhombohedron is the rare negative
form g (0552). They are somewhat scalenohedral in habit
owing to the curvature of the faces, but without obtuse edges.
A few of the crystals have in addition the unit rhombohedron
; (1011) and the low negative rhombohedron e (0112), both in
very narrow faces, as seen in figure 4, plate 1.

1912] Eakle: The Minerals of Tonopah, Nevada ili

The measurements were fairly good, notwithstanding the
curvature of the main faces.

Measured Calculated
(5502) (0552) 106°30’ 106°44’
(5502) : (0552 73 16 73 13
(1011) : (0111) 74 51 74 (55
(1011) : (0552) 53 39 By}.
(1011) : (0112) 37 26 37 27
(0552) : (0111) 112 15 112 33

Manganocalcite.—Specimens of ore taken from the 1000-foot
level of the Belmont mine contain erystalline granular patches
of a light brown carbonate which turns dark brown when heated
and gives a strong reaction for manganese, but no iron. The
mineral is chiefly calcium carbonate containing manganese, but
the characteristic rose tint is missing. The grains of the mass
show some striated and curved faces and only the low rhombo-
hedron (0112) can be distinguished.

Siderite is given by Spurr as one of the minerals of the veins
but none of the specimens include this carbonate.

Rhodochrosite—The manganese carbonate is of very rare
occurrence in the deposit. In the crevices of some of the quartz
specimens from the Montana-Tonopah mine a few pale rose
crystals of minute size occur singly. They are made up of the
steep scalenohedron y (3251) terminated by the base. The faces
of the scalenohedron are striated parallel to their basal edges
and the base is invariably dull. The erystals are shown in
figure 5, plate 1.

Measured Caleulated
(3251) : (5231) 45°37’ 45°26’
(3251) (521) 70 50 70 47

Malachite and Azurite—Small amounts of both copper car-
bonates occur as stains and erystalline coatings. The malachite
associated with the calcite of the Mizpah vein occurs in delicate
acicular groups. The azurite is with much of the malachite as
light blue earthy material.

SILICATES: FELDSPAR, KAOLINITE, SERICITE, AND RHODONITE

Feldspar and Kaolinite-—The potash feldspar, classed as
adularia, is the prominent silicate of the gangue. It is all more

16 University of California Publications in Geology. [Vou.7

or less altered to pure white, or brownish white, masses and
much of it is completely kaolinized to soft white clay. This
kaolinization has been brought about by the action of acid or
alkali solutions and the soft masses in the upper zone of oxida-
tion are often impregnated with minute erystals of hornsilver.

Sericite —All of the original silicates of the rock were altered
by the original ascending solutions and the seant amount of
soft pearly sericitic muscovite now in the gangue is of secondary
formation.

Rhodonite-—The rich silver ore of some of the veins shows
pinkish bands of rhodonite included in the quartz. Much of
the kaolinized feldspar is stained a pale rose color resembling
impure rhodonite.

PHOSPHATES AND ARSENATES: APATITE, PSEUDOMALACHITE,
WAVELLITE, TURQUOIS, PHARMACOSIDERITE, AND

CACOXENITE

Apatite.—Minute erystals of apatite line the crevices in the
Valley View vein, from the 440-foot to the 640-foot levels. The
erystals are snow-white and measure about two millimeters in
length. They occur as innumerable erystals forming a coating,
and have iodyrite erystals implanted upon them. Some of the
crystals have been later coated with a glaze of hyalite. The
erystals are combinations of the hexagonal prism with upper base
and occasionally very narrow faces of the unit pyramid (fig. 6).
This apatite has been formed as a purely secondary mineral and
gives no test for chlorine or fluorine. It is probably the simple
caleium triphosphate.

Pseudomalachite——This rare copper phosphate occurs in
small globular incrustations on the quartz in association with
rhodonite and hiibnerite. The globular forms are of a bright
emerald-green color and have a finely fibrous structure resem-
bling malachite.

Wavellite.—Little spheres of white wavellite are implanted
on specimens of the vein quartz, but they are few in number.
Internally they have concentric-radiating, delicately fibrous,

structure.

1912] Eakle: The Minerals of Tonopah, Nevada 17

Turquois—Small amounts of pale green turquois, fading
into white opaque masses, occur in the crevices of the Mizpah
vein at the 600-foot level. The mineral is associated with black
manganese oxides and kaolinite, and occurs in the vicinity of
much iodyrite.

Pharmacosiderite.—The rare iron arsenate occurs as a coat-
ing on quartz at the 370-foot level of the Montana-Tonopah
mine. It is light yellowish green and occurs in distinct cubes,
with its tetrahedral symmetry indicated by diagonal striations.
A few erystals show small faces of the tetrahedron and narrow
faces of the rhombic dodecahedron. Deposited on this arsenate
are little botryoidal groups of an undetermined dark-red iron
phosphate with irridescent surfaces and ight brown altered rims.

Cacoxrenite—Radiating tufts of golden yellow and pale yellow
cacoxenite occur in the cellular quartz gangue of the Montana-
Tonopah mine, about the 500-foot level. The structure of the
minerals resembles burrs with short bristles, and the bristles or
needles often radiate from a central small circle like spokes from
the hub of a wheel. These bunches are typically deposited on
drusy quartz which is coated with brownish black velvety layers
of manganese oxide, or is colored brown or black by manganese.

SULPHATES: GYPSUM, JAROSITE, AND BARITE

Gypsum.—Very little calcium sulphate is seen in association
with the specimens examined, and the mines were quite free of
calcium compounds which could form this common secondary
mineral. Some of the fissure walls are coated with thin layers
of colorless selenite, and it occasionally forms a glaze on argentite
and on some of the other secondary minerals. Brilliant crystal
faces are seen on the coatings but there are no well-defined
crystals.

Jarosite—The hydrous sulphate, jarosite, is the most prom-
inent of the secondary minerals precipitated from the solutions.
It is characteristic of the lower zone of oxidation and is in elose
association with the larger part of the iodyrite. It generally
occurs in flaky masses and flaky coatings, varying from leht
ochre-yellow to dark reddish brown. These flakes under the
microscope are seen to be basal plates with rhombohedral edges.

18 University of California Publications in Geology. [Vou.7

Small crystals with bright reflecting faces also occur in the
crevices of earthy masses and as a deposition on the black
manganese coatings. The crystals are rhombohedrons with the
basal planes in about equal development, so their resemblance
to octahedrons and to cubes with the tetrahedron is quite marked
(fig. 7). Some of them have the rhombohedral faces striated
while the base is perfect.

The solutions which precipitated the jarosite contained both
the sodium and the potassium sulphates, and it is probable that
analyses would show the presence of natrojarosite as well as the
normal jarosite and gradations of one into the other. <A quali-
tative analysis made of the yellow flakes shows them to be jarosite
but with considerable sodium.

Barite.—The sulphate of barium does not occur abundantly
in the vein, yet masses of crystals covering several square feet
are found on the walls of some of the fissures. The crystals are
white and have the common basal-plate habit. Some are half an
inch thick and an inch or more wide. The large crystals consist
simply of the base ¢ (001) and prism m (110), while the smaller
ones have also narrow faces of the pyramid z (111), and brachy-
pinacoid 6 (010). Thin layers of hematite or limonite coat many
of them. Some of the stout plates are later parallel enlargements
of smaller plates and the interior crystal had often the brachy-
pinacoid, not present on the outer or enlarged crystal. Figure 8
illustrates the type of crystals.

Measured Calculated
(110) : (1T0) 78°21’ 78°29"
(110) : (010) 50 50 50 49
(001) : (111) 64 24 64 19
(110) : (111) 95 42 25 41

TUNGSTATE AND MOLYBDATE: HUBNERITE OR WOLFRAMITE, AND
WULFENITE

Hiibnerite or Wolframite-—The manganese tungstate occurs
in black platy masses in the compact quartz gangue and in very
thin plates in the cavities and seams of the gangue. All of the
material contains iron and is to be classed as wolframite rather
than as hiibnerite. The crystals are tabular parallel to the

1912] Eakle: The Minerals of Tonopah, Nevada 19

orthopinacoid and some of them are exceedingly thin and almost
transparent, with a deep red color. They are vertically fur-
rowed and striated and the least touch breaks them into slender
rods by the easy clinopinacoidal cleavage. Many of the broad
plates have frayed-out ends, while others are terminated by dull
bases. The predominating habit shows a broad, striated, front-
pinacoid grading into prisms and terminated by a rough base
and two small faces of the rear pyramid (111), as seen in
figure 9. Some of the stouter crystals gave very good readings
with the two-circle goniometer, since the striations did not pre-
vent good polar orientation. The prismatic zone was a multiple
of narrow striated faces and gave a train of wedges from which
only a few could be distinguished as definite forms. Since the
erystals are very thin, the pyramidal faces were all small, but
mostly very bright. One new pyramid (122) occurred on some
of the erystals, in good reflecting faces. The forms observed
on the crystals and the angles measured and calculated are as

follows:
e (001) m (110) d (211)
b (010) q¢ (830) o (111)
a 00) h (310) e (112)
(120) s (121) v (122) new
Measured Caleulated
6 p p
m © 110 49°48’ 90°00’ 50°27’ 90°00’
q $00 830 72 54 90 00 72 48 90 00
h 3.0 310 74 40 90 00 74 37 90 00
? 2 120 31 00 90 00 31 12 90 00
s —12 T21 30 34 63 34 31 00 63 41
d —21 211 67 05 66 21 67 29 66 10
(0) —1l Tl1l 50 00 54 00 50 14 53 42
G —ht T12 50 00 34 19 50 01 33 59
v —t1 22 30 50 45 14 30 48 45 15

Wulfenite—Thin basal plates of wulfenite occur associated
with barite and erystals of iodyrite. Twinned erystals of
iodyrite have been deposited on the wulfenite plates and are
therefore of later generation. The plates are almost colorless and

20 University of California Publications in Geology. (Vou. 7

are very thin compared to their lateral dimensions (fig. 10). The
forms and angles measured and calculated are as follows:

ce (001)
e (101)
w (102)
Measured Calculated
(001) : (101) Diol Dio
(001) : (102) 37 56 38 15

Mineralogical Laboratory,
University of California.

Transmitted March 4, 1912.

BULL. DEPT. GEOL, UNIV. CAL. Wl Tip (en 2

ia.)
oe! |=

ee ee _ el > a — ae

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1- 38, oe 30 6

“BY

GEORGE DAVIS LOUDERBACK

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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 2, pp. 21-38, pls. 3-6 Issued May 25, 1912

PSEUDOSTRATIFICATION IN SANTA
BARBARA COUNTY, CALIFORNIA

BY
GEORGE DAVIS LOUDERBACK

CONTENTS PAGE
Stratification, its meaning and Origin -..........2---.c.-c-cecc-seeece eee eee eee 21
ES mCOs imei CablONe seescc.t7weceseessvvece cco SS et tcee cca ec Seeecereeeecoccs tee seesc estes ee soeeseseent 22
"ANS ETE NTE AS TSE oe ee 23
General nature of the formations involved ...........2.22..22..22::2:02::e00eeeeeeeeereeeeees 28
Occurrence and appearance of expoOSuTes ..............-.----c-:c--cc-eceeeeeeececeeeeeeeeeeeees 24
Determination of original structures -................:eecceccceceeseeeceeeeeeeeggeececeeeeeeeeees 24
Subordinate secondary layers -......-......:.--c-ccscceee-c-cceceeeeeceeceeeetseceeeeeeeeceeeeeseesees 25
TEAS GRECO SECT CES cw te Ee et a ee 25
Cementeot ameunated! Layers ...-22..--2c2:secce--¢2czecteencdecesetece cot eeccetecesederecedece eeezensese 26
SS ENICIMB TD C11 CLINGS emmeeseet as tee eile Re earn ce ee ees ctecat gens ee eee 27
TB app eae Oph AE a ONCE ANDY GAUSS OES eae a Pepe nl nt ee ree aie eee 28
Necessary conditions for production of observed aieagicne a teeae erator 29
Discussion of origin of subordinate layers -...........0...0.222. 22.220. 22c eee eee eee 30

Stratification, its meaning and origin.—Stratification as ap-
plied in structural geology to rock formations may be defined as
an arrangement in layers or ‘‘beds’’ as a result of the processes
of sedimentation or of the extravasation of sheets of lava.

1 There is some difference of usage here, and many geologists do not
include the bedded lavas as stratified formations. Their common oceur-
rence in beds; their formation of series either alone or with their inter-
bedded tuffs, or interstratified in the sedimentary series; the fact that their
bedded form is due to the same fundamental conditions as for sedimentary
strata (surface conditions, gravity and a pre-existing floor) ; the possibility
of using their attitudes and deformations in exactly the same way as
those of sedimentary beds for determining structural relations and earth
movements, mark them fundamentally as stratified in the same sense in
which the sediments are.

The usage common in geological text-books of making a sharp distine-
tion between stratified or sedimentary and massive or igneous rocks with-
out further qualification or comment ignores some very important relation-
ships. Surface igneous rocks are not only commonly stratified, but often
also sedimentary. The volcanic tuffs frequently form stratified sedi-
mentary formations of great thickness and areal extent, as for example in
the Mesozoic and Tertiary areas of many of the western states.

22 University of California Publications in Geology | Vou.7

The production of geologic bodies by these processes is brought
about by the settling, precipitation or spreading out of the com-
ponent materials on some preéxisting basement or floor and the
building up of the mass by the addition of fresh material
normally to the upper surface of the deposit. The basement or
floor may be the basin of a sea or lake, the bed of a stream, the
surface of the ground, more rarely the floor of an underground
space or cavern, ete. The appearance of laver-structure is caused
by the varying nature or intensity of the agents supplying the
material or by the sorting action of the medium or media through
which the material passes before coming to rest. The distinetion
between layers may therefore depend on differences in composi-
tion, size of grain, or perhaps only on color change, or on the
occurrence of thin bounding layers or separation planes between
tabular masses of the same nature. The thicker layers are gen-
erally referred to as strata or beds and the thinner as laminae.

Stratification as above defined is geologically a very important
condition. It indicates an essentially superficial or epigene origin
of the formations exhibiting it, and except for the lava sheets
which are set apart by a special group of characteristics, is a
distinctive structure common to all of those closely related
processes which are grouped under the general name of sedi-
mentation. Furthermore, chiefly as a result of gravity control
in these processes, the separation planes between the layers—the

stratification planes—are in most types of these deposits formed
horizontally or at only a shght inclination to the horizontal.
This is a fundamental datum for structural geology, for with it
as a basis we may judge of the nature and amount of earth
movements that have tilted, folded, and otherwise disturbed the
stratified formations.

Pseudostratification.—In this paper the writer will describe
occurrences in which there is a layer-structure in clastic sedimen-
tary rocks giving the appearance of beds and often laminae, but
not produced by the processes that brought the rock masses into
existence. Furthermore, these structures have been formed both
with horizontal attitude and with considerable inclination to the
horizontal without relation or reference to the amount of tilting
that has been suffered by the formation in which they are found.

1912] Louderback: Pseudostratification 23

If the genetic relationship were not to be insisted upon in the
definition of the term stratification, but simply the arrangement
in layers or beds, such structures might be referred to as second-
ary bedding or secondary stratification. But in the opinion of
the writer, it is desirable to limit the term stratification to the
genetic types outlined above and to consider the genetic relation-
ship as an essential element of the concept stratification. On
this basis the term pseudostratification is proposed and will be
used in the present paper for any structure that closely simulates
stratification as defined above, but which is not the expression
of an original laying down of the rock-mass layer upon layer on
some preéxisting basement or floor. The individual bed-like
masses may then be called pseudostrata, any thin subdivisions,
pseudolaminae.

Territory studied.—The territory within which these phenom-
ena were particularly studied les in the central part of Santa
Barbara County, California, within the Lompoc quadrangle of
the United States Geological Survey, in the hilly country between
Los Alamos Valley and Sisquoe Creek (often called ‘‘river’’),
and especially in the vicinity of Cat Canon (Canada del Gato),
and the country between it and Foxen Canon.

General nature of formations involved.—The rocks in which
these structures are chiefly developed are massive friable Tertiary
sandstones—part of the Fernando formation of the Geological
Survey—which here usually show only a light development of a
cement and which generally crumble down into smooth, rounded
slopes showing no surface exposures and rendering the problem
of determining the detailed structure of the region rather
difficult. The background of plate 5 illustrates the type of
topography involved. Uncemented conglomerate or pebbly
sandstone may also show lke structures.

This territory is in part a petroleum producing district and
has therefore been subject to considerable ‘‘prospecting’’ in
which the determination of the structural details was an import-
ant part of the work, and the common absence of exposures

24 University of California Publications in Geology [Vou.7

showing the real attitude of the strata, and the presence of
exposures of pseudostrata, have produced considerable confusion.?

Occurrence and appearance of exposures.—The usual oceur-
rence of exposures of pseudostrata is on the sides of stream cuts
or small canons, well up towards the top near where the canon
slope intersects the normal hill slope. We may usually dis-
tinguish, below the soil layer, a layer of friable sandstone gener-
ally extending from one to five feet below the surface, sometimes
to ten or more feet. Then follows a more distinctly indurated
layer with parallel or approximately parallel boundaries and
varying in thickness from two to four or five feet in different
localities. Below this follows a more friable layer, partly or
wholly covered with hill wash or talus, which covers the slope
from there down to the stream channel. Sometimes these ex-
posures are produced by small landslides or local washouts on
some slope. They may vary in length from twenty or thirty feet
to a hundred yards or more.

As a rule the attitude of the exposed layers roughly coincides
with the surface slope

most commonly the general hill slope,
occasionally the canon slope. In making a section, therefore,
across a ridge in areas where no other kinds of exposures are
found, it appears as if the ridge were anticlinal in structure.
Such an appearance is illustrated on the hills south of Foxen
Cafon, and is particularly interesting because the real structure
under one of the pseudoanticlinal areas is synclinal.

The appearance of a pseudostratum in exposure is shown in
plate 3. Without careful examination with this particular
problem in mind, it is not always easy to distinguish such ex-
posures from those of the original stratification of sedimentation.

Determination of original structure.—The real attitude of the
formations with reference to their original planes of deposition
is frequently very difficult to determine. Bare fossil layers,
thin streaks of gravel in the sand, or shaly layers, occasionally

2 For the general distribution of formations and for general structures,
reference may be made to the geologic map in Bulletin 322 U. 8. Geol.
Survey, on the Santa Maria Oil District. On this map structure lines are
made to stop before reaching the area where pseudostratification is best
developed, and the interpretation of the general structure is evidently
affected by the occurrence of these exposures and the general lack of
distinet stratification exposures.

1912 | Louderback: Pseudostratification 20

furnish the proof. In a number of cases where the bed in
which the pseudostratification had developed was itself without
original visible structure lines, a recent slide or wash, or an
excavation made for the purpose, showed distinct structure lines
in an under- or overlying layer, especially in shale streaks, or in
layers with arranged micaceous materials. A test area of about
two square miles, where the only exposures appeared to be those
of pseudostratification, was worked over, and it was found that
on the careful examination of the deeper slides and washes, and
particularly of a series of excavations, a consistent group of
observations could be obtained determining the original strati-
fication and the attitude of the original beds. It showed a very
open syncline while the more evident exposures of pseudostrata
gave consistent indications of an anticline (a pseudoanticline),
the axis of the syncline being quite a distance south of the axis
of the pseudoanticline.

Subordinate secondary layers.—All of the pseudostrata do
not show within themselves distinct minor layers, but in some
they are very well developed, and vary from two or three milli-
meters in thickness up to ten or more centimeters. Layers of
this latter thickness down to those of two or three centimeters
are more common than the very thin ones, which may be ealled
pseudolaminae. They are often bounded by separation planes
and samples may be removed from their exposures as thin plates
or approximately parallel bounded blocks. Such a block is shown
in plate 6, figure 3. These features are more common in pseudo-
strata occurring with dips of ten to twenty degrees or more.

Sometimes these minor layers within the pseudostrata are
quite parallel and continue for a number of yards—perhaps
throughout the whole exposure. Sometimes they may be curved
or may cut obliquely across the pseudostratum, or one division
plane may cut obliquely across the others. Such oblique and
curved arrangements may give rise to appearances that may be
called pseudo-current bedding. Typical cases are illustrated in
plate 4 and plate 5.

Pseudofolds—It has already been described how the ex-
posures Over an area may consistently give the impression of
a folded arrangement of the strata. Plate 5 illustrates a some-

26 University of California Publications in Geology {Vou.7

what different case. It shows a structure that a number of
men have taken to be an anticline, although the strata on both
sides have not the same appearance. On the left can be seen
the original stratification, on the right the pseudostratification.
The original stratification does not show itself to the eye in the
right hand part of the exposure even upon careful examination.
The more indurated pseudostratum appears to be cross-bedded.
The vertical parallel columnoid appearance of the layer under
the pseudo-crossbedded stratum is simply a channeling of the
surface of the uncemented sand, in part by dripping water,
chiefly by the action of falling sand particles dislodged by various
agents or blown by the wind.

Cement of indurated layers.—Some of the indurated layers
are grayish white, others yellowish or brownish, and many show
in part a color banding, or irregular color blotches suggesting
concretionary deposition of cement. Small white or yellowish
veinlets of secondary deposition are occasionally found, and the
minor layers (and laminae) are often separated by coatings
which vary from one-half to three millimeters in thickness, and
may be brown or yellow or almost white.

The first material examined was that of the white veinlets, as
they were presumably of the purest and most easily separable
secondary substance. It is dull opaque white and rather porous
and has the appearance often presented by secondary crusts of
calcium carbonate or dull sinter.

This material is insoluble in hydrochloric acid, infusible
before the blowpipe where it sinters and gives up water, easily
soluble in hydrofluoric acid with httle or no residue, and fuses
with soda to a clear glass. Under the microscope it is chiefly
amorphous with a showing here and there of anomalous double
refraction. These properties, combined with the refractive index,
determine it to be amorphous hydrous silica—opal.

The general cement which has indurated pseudostrata and
pseudolaminae is essentially of the same nature in all of the
samples examined. The amount of carbonate material is very |
slight or absent—practically negligible. The ochreous yellow or
brown rocks, the predominant types, owe their color to hydrous

iw)
+]

1912 | Louderback: Pseudostratification

oxides of iron, which occasionally act as a cement of minor im-
portance. The chief rdle is played by opaline silica, as the
following tests indicate.

Boiling or long standing in contact with concentrated hydro-
chlorie acid turns the rock white and yields a ferruginous solu-
tion, accompanied by a slight superficial disintegration, a few
of the surface grains becoming disconnected from the mass and
settling to the bottom of the liquid. This disintegration action
is probably due to physical action, however, more than to the
freeing of grains by the solution of the cement.

Boiling with hydrofluoric acid quickly disintegrates this mass ;
the grains fall apart and we have a clear sand as a residue.

A similar boiling with potassium hydroxide solution com-
pletely disintegrates the rock into a ferruginous sand, if a yellow
or brown specimen be used, or, if it be one previously leached by
hydrochloric acid, a clean white sand results.

A preparation of the sandstone cleared by hydrochloric acid
treatment shows distinctly under the microscope the amorphous
coating on and between many of the grains, and a crushing of
the grains between slide glasses disconnects some of the coating,
which shows the characteristics of opaline silica.

The usually ochreous-colored coatings or separation laminae
that are often found where distinct separable layers or laminae
occur are in like manner determined to consist chiefly of
amorphous hydrous silica, colored with ferric hydroxides, and
including minute crystal fragments much smaller than the
average grain of sandstone, but evidently derived from it
mechanically.

Sand pendants—In a few places where the pseudostrata
were undermined by erosion or caving, small sand pendants and
mammillations were observed. These vary from slight just notice-
able protuberances up to pendants ten or more centimeters in
length. They may be roughly cylindrical, with various irregular
cross-sections, or, in the shorter ones, conical.

These all have a central core of whitish, dull, opaque, porous
opal, similar to that of the white veinlets described above, and
usually showing a distinct concentric structure. The axial por-
tion of the concentric structure may be hollow. The outer

28 University of California Publications in Geology |Vou.7

portion, representing usually from about the same to double the
thickness of the core layers, is of sand cemented by silica, and
more or less colored by iron.

These forms probably originated from plant rootlets which,
during their decay, became loci for the silica deposition which
is rather pure where the rootlets themselves originally were.
The outer sandy coatings are bound to the axial portions by
silica cement deposited upon and in extension of the siliceous
nucleus. They often have the appearance of stalactites. Some
small sand pendants are shown in plate 6; their external forms
in part broken and not terminated, in figure 2, and longitudinal
and transverse sections, showing the silica core and central hole,
in figure 1.

Explanation of phenomena—In seeking for an explanation
of these phenomena the position and attitude of the pseudostrata
with respect to the surface of the ground is of fundamental
importance. As to position, the more indurated layers always
have their tops near the surface, rarely over ten or twelve feet
below it. In attitude they generally agree with the surface
slope, sometimes dipping at a shghtly greater angle than the sur-
face. In the cases observed where they dip at a less angle than
the surface, and then usually outcrop, the surface slope has
been very recently modified by erosion, such as the undermin-
ing action of a stream or land sliding and the consequently
accelerated hill wash in its vicinity.

The general appearance is often that of three layers or more;
when three they are the upper friable below the soil, the
indurated, and the lower friable. The appearance of more than
three is due to pseudolamination of the indurated layer. There
is, however, essentially one layer to account for—the main in-
durated pseudostratum. This appears to be due to a superficial
belt of cementation within the weathering zone, and dependent
on the aridity of the climate, the lower limit of cementation being
the lower limit of migration of the silica under normal conditions.

The action is, therefore, analogous to the formation of hard-
pan in soils* from which it differs chiefly in the fact that it
occurs in the midst of a rock formation below the definite soil

3 See Hilgard, E. W., Soils (New York, 1910), pp. 162 and 183.

1912] Louderback: Pseudostratification 29

layer, and that it produces a structural appearance closely
simulating stratification. It might readily happen that similar
phenomena would arise from the deposition of a calcareous or
ferruginous instead of a siliceous cement.

Necessary conditions for production of observed phenomena.—
An essential condition for the formation of pseudostratification
as exhibited in the localities studied is a porous, moderately even-
grained sediment, massive over the areas exposed. That is, it
must be without definite segregation of the material into layers
of different grain, or alternations of more porous and less porous
layers, or other definite marks or conditions resulting from
original stratification that might influence the percolation or
deposition of cement, and disturb the formation or appearance
of the new and independently oriented lines of structure.
Furthermore, the climatic conditions would have to be such that
while water would be supplied to dissolve, transport and deposit
the cement, it would not be humid enough to wash all such
solutions into a general ground-water system, and so prevent
cementation near the surface.

The rainfall, in other words, should mainly be by short, dis-
connected showers, giving but a moderate water penetration.
This degree of aridity is commonly realized in the western states.
The fact that the dip of the pseudostrata is often greater than
that of the surface is probably due to the greater penetration
of the rain lower down the slope, where the ground may be
supplied not only by the direct dropping of water from the
atmosphere, but also by the surface movement of the rain sheet
from the higher slopes.

The predominance of silica in the cement is probably due to
the composition of the sands here involved. Clay substance is
very slight in amount, calcium and magnesium unimportant
because there is a dearth of decomposable basic feldspar or lime-
magnesium-iron minerals, while silica can be derived from the
plentiful orthoclase and acid plagioclase, and perhaps from the
abundant quartz.

An important auxiliary condition which renders the pseudo-
stratification the more easily mistaken for true stratification is
the disintegrable nature of the original formations which yield

30 University of California Publications in Geology [Vou.7

a regolith which very effectually hides such indications of strata-
fication as are present, the only exposures showing any struc-
tural characters whatever over considerable areas being exposures
of pseudostrata.

Origin of subordinate layers.——A more difficult matter to
explain is the very distinct layers and lamellae into which some
of the pseudostrata are divided, and which are illustrated in
plates 4 and 6. These are frequently parallel-sided, sharply
defined and physically separable, either by simply lifting the
upper from the lower or after a light blow from a hammer, and
often with siliceous coatings separating them.

While not visible as such, it seems possible that the cement is
deposited with a more or less banded structure due to different
penetrations and different levels of depositions in different
seasons. In hardpans, where calcareous or ferruginous cement
is abundantly developed, a roughly horizontal banding may be
distinctly visible. Any agent, then, producing fracture in the
rock,—temperature changes, plant action, even the drying out
and shrinkage of the siliceous cement,—would tend to break it
along the banding surfaces.

In a specimen collected, a distinct silica-coated, roughly
parallel-faced layer about three centimeters thick, is a crack run-
ning somewhat obliquely to the bounding surfaces, and traceable
for about fifteen centimeters on one side and six on the other.
It is very distinctly not due to pressure or to faulting or shear-
ing, and it 1s apparently not a bounding line between two layers
of deposition of cement. It may be due to shrinkage or tempera-
ture changes. The plane determined by it is partly occupied by
a coating of silica. It is shown in plate 6, figure 3.

Some of the silica coatings are peculiarly marked by an
irregular network of minute furrows like numerous small worm
tracks. These are evidently the impression of fine rootlets, as
individuals can be traced and their gradual tapering and branch-
ing distinctly made out. Such thin mats of interlocking rootlets
are quite competent to extend and complete cracks that may have
been started by other agents. They are to be expected only in
an exposure or quite near the surface.

The best separation planes were noted in the pseudostrata

1912 | Louderbach: Pseudostratification ol

with considerable dip. Some of these planes appeared as if they
had been formed by a bodily slipping of the wet, poorly cemented
sand material, and the consequent development of a plane of
more easy water percolation, and therefore silica deposition.
Such shpping surfaces may be plane for several meters, or they
may be short, irregular, or curved and give the appearance of
cross or current-bedding.

Some of the lamellae show a visible banding of the fer-
ruginous cement parallel to the bounding surfaces. This may
in part antedate the formation of the layers, and may have
contributed to their production, but in several cases carefully
examined, the distribution of ferruginous bands was so peculiarly
related to the form of the layer, that it seems necessary to believe
that they were later and dependent on it for their form of

deposition.

Transmitted March 4, 1912.

EXPLANATION OF PLATE 3

+ se

Typical exposure of an approximately horizontal pseudostratum.
veal stratification dip (not visible) is down to the right at. ab

Tinaquaice grant, Santa Barbara County.
‘

7
[32]
e 7
6

PUBL. BULL DEPT... GEOL [LOUDERBACK] VOL. 7, PL. 3

EXPLANATION OF PLATE 4

Minor pseudostrata and pseudolaminae. Tinaquaic grant.

Fig. 1.—Lamination approximately parallel to cafion slope. Narrow
and more prominently weathering separating layers chiefly of silica. True

dip away from observer (north, 8°). Dip of pseudolamination, east 30°.

Fig. 2.—Same locality, showing pseudostratification planes as planes of

separation.

[34]

Si <<

UNIV. CALIF. PUBL. BULL. DEPT, GEOL. [LOUDERBACK] VOL. 7, PL. 4

‘
yea
'
. ‘
’
-
©
‘
‘
'

EXPLANATION OF PLATE 5

Pseudoanticline. Upper Cat Cation, looking east. True stratification
visible on left, dipping north; pseudostratification on right, dipping south.
The main pseudostratum has a cross bedded appearance. The columnar

layer below is sand fluted by dripping water and falling particles.

[36]

EXPLANATION OF PLATE 6

Sand pendants and minor stratum.

Fig. 1—Sections.of sand pendants split longitudinally and broken
transversely. The inner light portion is chiefly hydrous silica, the outer
dark portion, sand cemented by silica. The central hole is seen in the
lower transverse sections and in part in the upper right-hand longitudinal

section. Natural size.

Fig. 2.—Portions of sand pendants to show outer surface and general

form. None show complete length. Natural size.

Fig. 38.—Separated layer from exposure shown in plate 4, figure 2. The
white edges of the secondary silica layers are well shown. The upper
surface is coated with such a layer showing ramifying channels as if
impressions of plant rootlets. Joint planes transverse to layers are also
coated with silica. One newly developing crack is shown on left side, and
its walls are also coated with siliea. The light colored blotches are due
to varying amount of hydrous oxide of iron. It is disposed in bands
parallel to the layer surfaces and also in irregular areas determined by

the concretionary type of deposition. *%4 natural size.

[38]

UNIV CALIF RUBEN BIEL: ) GEOL, [LOUDERBAC}

Figs. 1 and 2

OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

eae GEOLOGY
|. 7, No. Bs pp. 39-46, 10 text-figures Issued September 12, 1912

ECENT DISCOVERIES OF CARNIVORA IN

_ THE PLEISTOCENE OF RANCHO
| LA BREA

JOHN C. MERRIAM

j PN
UNIVERSITY OF CALIFORNIA PRESS
BERKELEY

UNIVERSITY OF CALIFORNIA PUBLICATIONS —

NotE.—The University of California Publications are offered in exchange for th
eations of learned societies and institutions, universities and libraries. / Complet
all the publications of the University will be sent upon request. For sample copies
publications and other information, address the Manager of the University Press, Be
California, U. S. A. All matter sent in exchange should be addressed to The
Department, University Library, Berkeley, California, U. S. A. i se

Orto HaRRASSOWITZ R, FRIEDLAENDER & SOHN
LEIPZIG | ; BERLIN

Agent for the series in American Arch- Agent for the series in American Are
aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany, Geolog
Education, Modern Philology, Philosophy, Mathematics, Pathology, Physio.
Psychology. Zoology, and Memoirs. Se

Geology.—Anprew C. LAwson and JoHN C. Merriam, Hditors. Price per volume,

Volumes 1 (pp. 435), II (pp. 450), IIL (pp. 475), IV (pp. 462), V (pp. 448),
completed. Volume VI (in progress). aE

Cited as Univ. Calif. Publ. Bull. Dept. Geol.

Vol. 1, 1893-1896, 435 pp., with 18 plates, price $3.50. A list of the titles in
this volume will be sent on request. . ¢

VOLUME 2.

i. The Geology of Point Sal, by Harold W. Fairbanks...) 300.0 y
2. On Some Pliocene Ostracoda from near Berkeley, by Frederick Chapman..........._..
3. Note on Two Tertiary Faunas from the Rocks of the Southern Coast of Vancouver
Island, by. J. OC. Merriam. 2.2.2 cee ec ce
4. The Distribution of the Neocene Sea-urchins of Middle California, and Its Bearing
on the Classification of the Neocene Formations, by John C. Merriam....................
5. The Geology of Point Reyes Peninsula, by F. M. Anderson............-.-----csc--escereceeesneens
6. Some Aspects of Erosion’in Relation to the Theory of the Peneplain, by W. S.
Manrrien, Smith.) sk oe eee eee need hag nea co due Scan aaa ea 32, See 20c a8
7. A Topographic Study of the Islands of Southern California, by W. 8S. Tangier/Smith 40¢ ~
8. The Geology of the Central Portion of the Isthmus of Panama, by Oscar H. Hershey 30¢ |
9. A Contribution to the Geology of the John Day Basin, by John C. Merriam =35C. am
10. Mineralogical Notes, by Arthur S. Hakle....u...2..2.2c:--cce-nccceeneceeneceoncnererceoecesneeteas xe Le ae
11. Contributions to the Mineralogy of California, by Walter C. Blasdale...............
12. The Berkeley Hills. A Detail of Coast Range Geology, by Andrew ©, Lawson and
Charles: Palache :.-. 2st sccgis-o kta ce steced <n spte ieee can ene aero tap etter oe So pas ene

VOLUME 3.

The Quaternary of Southern California, by Oscar H. Hershey .......-...22222---2--eseeee noes
Colemanite from Southern California, by Arthur S. HEakle....-.2222.-----:e---ceesetee-e
. The Eparchaean Interval.__A Criticism of the use of the term Algonkian, by
Amdrew O> Lawson oi .sic222-c2-o--neecnsenenctoncne nuescoeietns enag get enes ence ae ces Herat eae tine eae ea
Triassic Ichthyopterygia from California and Nevada, by John C. Merriam............
The Igneous Rocks near Pajaro, by John A. Reid .......-..---2---.-n----n-e-ceeeeeeneereneeeeneeennes
Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller —
Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by
Am Grew ©, TiawSou :.-ccs-cusaccccees oe cess eet awa ON aan oe eee
Palacheite, by Arthur S. Hake... ------------2s--ceceec-cceceecenerccceen cee nerce reer eneneeeesenneenanentannnnaneay =
Two New Species of Fossil Turtles from Oregon, by O. P. Hay. ;
A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair,
Nos. 10 and 11 im On€ COVED. ....-2--..2------0-------0-ennee enn enenere nanan ce cenenensensnnbesaneaetenenenes ee
12. New Ichthyosauria from the Upper Triassie of California, by John C. Merriam..... -
18. Spodumene from San Diego County, California, by Waldemar T. Schaller... zs
14. The Pliocene and Quaternary Canidae of the Great Valley of California, by
Tol Cy. Merriam «2......-----c-e-cceccceeceeceeceennecconeeceecensnenecasenannsnnesnanaeensenecasenecsnneareammecnnronmannns
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson......._. ag
16. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam...
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew C. —

SIS is

PSS wag

wey

William J. Sinclair and BE. L. Furlong... -..------s----eso-te--seensporeerennseceenecears savannas si
21. A New Marine Reptile from the Triassic of California, by John C. Merriam
92. The River Terraces of the Orleans Basin, California, by Osear H. Hershey...

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 3, pp. 39-46 Issued September 12, 1912

RECENT DISCOVERIES OF CARNIVORA IN
THE PLEISTOCENE OF RANCHO
LA BREA

BY;

JOHN C. MERRIAM

INTRODUCTION

Until recently no remains of true bears and none represent-
ing eats of the puma type have been discovered in the collections
of carnivore remains obtained at Rancho La Brea. Absence of
these two groups has therefore been generally considered as one
of the peculiar features of this fauna. Bears of the arctothere
eroup are known from fragmentary remains representing a
large species which has been tentatively designated as Arcto-
therium californicum.t True eats are represented at Rancho La
Brea by the gigantie lon, Felix atroxr bebbi,? and by wild-cats
of the type of Lynx californicus fischeri.’

Included in collections from Rancho La Brea which have
been prepared for study within the past year there are several
fragmentary specimens which evidently represent a bear of the
Ursus type, and a eat closely related to the existing pumas. These
discoveries are of some significance in connection with studies
on the distribution of the fauna of Rancho La Brea with refer-
ence both to time and to space, and it is therefore deemed desir-
able to record the information available.

1 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol. vol. 6, p. 165, 1911.

2 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol. vol. 5, pp. 291-304,

1909.
3 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol. vol. 5, p. 394, 1910.

40) University of California Publications in Geology (Vou.7

Ursus, sp.

The remains referred to Ursus consist of an atlas (no. 12786)
and fragments of other vertebrae. The atlas (figs. 1 and 2) is dis-
tinctly of the ursid type. It resembles Ursus, and differs from

AN ““ \
ie

Figs. 1 and 2. Ursus, sp. Atlas. No. 12786, X 1%. Fig. 1, superior
view; fig. 2, posterior view. Rancho La Brea Beds.

Arctotherium in the character of the posterior opening of the
vertebrarterial canal. The general form of the transverse pro-
cess seems also to resemble Ursus more closely than Arctotherium,
although this cannot be demonstrated as the ends of these pro-
cesses are broken away.

In such material as is available for comparison the atlas of
Ursus differs from that of Arctotherium in the location of the
posterior opening of the vertebrarterial canal. In Ursus this
opening is on the upper side of the posterior face of the trans-
verse process; in Arctotherium (fig. 3) the posterior opening is
on the upper side of the transverse process some distance in
advance of the posterior margin, much as in the Canidae. In

1912] Merriam: Carnivora of Rancho La Brea 4]

Ursus the posterior articular faces of the atlas commonly extend
backward on angular processes which project some distance
behind the proximal region of the posterior border of the trans-

Fig. 3. Arctotherium simum Cope. Atlas, superior view. No. 3035,
1%. Pleistocene of Potter Creek Cave, California.

verse process. In Arctotheriuwm the posterior border of the
transverse process is shghtly notched, but the plates supporting
the posterior articular faces are not as prominent as they may
be in Ursus, and there is a very narrow posterior notch. In
both of the characters just mentioned atlas no. 12786 from
Rancho La Brea is distinetly ursine rather than aretotherine.

The atlas may be referred to the genus Ursus, but specific
determination is hardly possible with the material available. In
form, size, and position of the posterior opening of the verte-
brarterial canal the atlas specimen from Rancho La Brea is
nearer to the black bear than it is to the grizzly. The form of
the transverse processes differs somewhat from both black and
erizzly. Unfortunately in the fossil specimen these processes are
ineomplete on both sides, and no distinctive characters can be
based upon them.

The animal represented by the ursine atlas from Rancho La
Brea was about as large as a grizzly of average size, but was
very considerably smaller than the gigantie Arctotherium cali-
fornicum known from these beds.

MEASUREMENTS OF ATLAS
Least anteroposterior diameter on dorsal side... 25.3 mm.
Greatest transverse diameter across anterior articular faces............ 65.5
Greatest height of neural canal..............2..22..22.2222-ceeeeeeeeeeeeee eee 26.

42 University of California Publications in Geology [Vou.7

FELIS, near HIPPOLESTES Merriam, C. H.

’

The remains referred to the puma group of felines consist
of a portion of a mandible and four perfect metapodials. The
jaw and two of the metapodials were found near together and
may represent the same individual. They agree approximately
in form and dimensions with the corresponding elements of exist-
ing cougars included in Felis hippolestes, but it is hardly safe on
the basis of such fragmentary material to assume that the species
can be definitely determined.

The jaw fragment (fig. 4) is almost identical in dimensions

Fig. 4. Felis, near hippolestes Merriam, C. H. Fragment of mandible.
No. 19525, natural size. Rancho La Brea Beds.

with the average of several specimens of Felis hippolestes, but
differs slightly in the shape of the coronoid process from the
normal form in this species. In most specimens of F. hippo-
lestes a line drawn between the middle of the posterior side of
the condyle and the most posterior part of the upper region of
the coronoid process will lean forward. In the specimen from
Rancho La Brea such a line is tipped strongly backward. This
is generally considered as a characteristic of the tiger, and is a

1912] Merriam: Carnivora of Rancho La Brea

H. Metapodials, nat-

Felis, near hippolestes Merriam, C.
ural size, Rancho La Brea Beds: fig. 5, metacarpal IV, anterior view, no.
19526; fig. 6, metatarsal V, anterior view, no. 12245; fig. 7, right meta-
tarsal III, anterior view, no. 19290; fig. 8, left metatarsal III, proximal

Figs. 5 to 8.

end, no. 19290. Fig. 9. Felis hippolestes Merriam, C. H. Proximal end of
left metatarsal III, natural size, Recent, California. Fig. 10. Felis atror
bebbi Merriam, J. C. Proximal end of left metatarsal III, natural size,

no, 12679, Rancho La Brea Beds.

44 University of California Publications in Geology [Vou.7

feature of all specimens of Felis atror thus far examined. In
the Rancho La Brea specimen the character just mentioned is
coupled with distinctly greater anteroposterior diameter of the
upper portion of the coronoid process. This deviation from the
form of F’. hippolestes is, however, so slight that it may have no
real taxonomic value.

Of the metapodials representing the small Felis form, meta-
carpal four (fig. 5) is very slightly larger than that of an
average specimen of F. hippolestes, but is distinguished by
the character of the antero-medial region of the shaft. In the
specimens of PF. hippolestes available this area of the shaft is
regularly rounded, and almost without tendeney to development
of an antero-medial angle. In the Rancho La Brea specimen
the proximal half of this region is decidedly angular, and is
swollen medially so as to produce a noticeable prominence.
There is reason to doubt that this difference is due solely to
individual variation. .

The specimen representing metatarsal five (fig. 6) is a lttle
larger than that of the individuals of F. hippolestes available.
The Rancho La Brea specimen differs from the Recent ones only
in greater width of the postero-medial face for articulation, with
metatarsal four, and in the more distinetly angular nature of
the proximal portion of the lateral margin.

A right and a left metatarsal three (fig. 7), evidently from
the same individual, are a little larger than the corresponding
elements of an average specimen of F’. hippolestes. The dimen-
sional relations between these elements, and the metatarsal five
referred to F’. hippolestes above are almost exactly similar to
those between metatarsals three and five in the Recent F. hippo-
lestes. The third metatarsals differ distinctly from those of
Felis atrox and Felis leo in certain characters in whieh these
two forms are alike; and in the respects in which they differ
from F’. leo and F. atroxr they are almost identical with F’. hippo-
lestes.

The resemblance of metatarsal three in the Rancho La Brea
specimens to the pumas, and its separation from the lions, is
particularly noticeable in the form of the proximal end, and
in the nature of the facets of this region. (See figs. 8 to 10).

1912] Merriam: Carnivora of Rancho La Brea 45

In the puma the roughly hammer-shaped proximal articular face
shows commonly a very narrow notch on the medial side, and
the posterior end of the facet terminates with a clearly-defined
margin some distance anterior to the posterior tubercle of the
proximal end of this bone. In the F. atroxr and F. leo the
medial notch is very wide and the posterior end of the proximal
articular facet reaches almost to the end of the posterior proxi-
mal tuberele. In the puma the posterior lateral face for articu-
lation with metatarsal four is entirely distinct from the proximal
articular face. In the F. leo and F. atror this face extends
almost if not quite to the latero-proximal angle of the bone. In
the third metatarsals (no. 19290), from Rancho La Brea, the
proximal facets correspond in form to those of the puma.

The third metatarsals in no. 19290 differ in general form
from those of F’. hippolestes very slightly. They appear a little
heavier anteroposteriorly in the proximal region of the shaft,
and the antero-lateral side of the proximal end tends to
develop a small tubercle between the proximal face and the
antero-lateral face for metatarsal four. In the puma the shaft
narrows gradually for some distance down from the proximal
end, and there is no suggestion of a tubercle in the proximo-
lateral region.

The two specimens representing metartarsal three are evi-
dently from a form of the same type as that seen in metatarsal
five and metacarpal four described above. This form is not
separable from the puma group by any characters thus far
known.

Possible relationship of this form to the jaguar, Felis onca,
has been considered, but the jaw sems to differ distinctly from
that species. No material representing the extremities of the
jaguar is available for comparison, but the nature of the mandible
would seem to suggest that the Rancho La Brea form is a puma
rather than a jaguar. Slight differences between the elements
available and the corresponding parts of pumas at hand for
comparison suggest that the Rancho La Brea specimens may
represent a species or a subspecies different from FP’. hippolestes,
and possibly a form as yet undescribed.

46 University of California Publications in Geology [Vou.7

MEASUREMENTS
Mandible.
Height from inferior margin below masseterie fossa to summit
Of (COTONOId! PIOCeSS) <.icee-cteseeee ere 64. mm,
Height of summit of coronoid process above condyle .........-..- 37.
Transverse diameter of condyle 2.8. 30.8

Metacarpal IV
GGA GES Tek OM Ota sce cane pees ee ae eee eee ee
Least transverse diameter of shaft

Metatarsal III

Greatest length along middle of shat ......202:ccccecccee-steee eee 108.5
IWeast transverse diameter Os eShabdit eescseeee seeees eceecese eeueceee eeneneae 13.

Least anteroposterior diameter of shaft -2.2 2S... 10.9
Greatest transverse diameter of proximal end ............0.2------ 19.2
Greatest anteroposterior diameter cf proximal end .......,.........--..- 24.3

Metatarsal V

Greatest dem oth! coarse cases segues teeeaeys ee rses fees eer 95.6
Iueast transverse: diameter of shaft 220.2... 9.1

CONCLUSIONS

The apparent absence of arctotheres, of true bears, and of
cats of the puma group from the Rancho La Brea fauna, has
appeared to give this assemblage a distinetly ancient aspect com-
pared with other Pleistocene faunas in the Pacific Coast region.
There are still many peculiar features in the life of Rancho La
Brea which make it seem quite different from that of the Pleis-
tocene known from other localities of this province. Some of
these peculiarities will be interpreted as due to difference in
time, and some to difference in habitat. The known presence of
true bears, arctotheres, and cats of the puma group brings the
Rancho La Brea fauna into closer relation with the other Pleis-
tocene faunas of this region than had previously seemed possible.

ISITY OF CALIFORNIA PUBLICATIONS
se BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Issued October 10, 1912

NORTH SIDE OF MOUNT
DIABLO

BY es

— BRUCE L. CLARK

UNIVERSITY OF CALIFORNIA PRESS -
BERKELEY _
‘

5 UNIVERSITY OF CALIFORNIA PUBLICATI <

Notre,—The University of California Publications are*offered in exchange
eations of learned societies and institutions, universities and libraries. Comp
all the publications of the University will be sent upon request. For sample co
publications and other information, address the Manager of the University Press,
California, U. S. A. All matter sent in exchange should be addressed to The
Department, University Library, Berkeley, California, U. S. A. :

Orto HAaRRASSOWITZ ‘ R: FRIEDLAENDER & SOHN

LEIPZIG BERLIN i leg

Agent for the series in American Arch- Agent for the series in American A
aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany, Geolo
Edueation, Modern Philology, Philosophy, Mathematics, Pathology, Physiology, —
Psychology. Zoology, and Memoirs. « st = Tete. ela

Geology.—ANpbREW C. LAWSON and JoHN C. MerriAM, Editors. Price per volume, $3

Volumes 1 (pp. 435), IL (pp. 450), III (pp. 475), IV (pp. 462), V (pp. 448),
completed. Volume VI (in progress).

Cited as Univ. Calif. Publ. Bull. Dept. Geol.

Vol. 1, 1893-1896, 435 pp., with 18 plates, price $3.50. A list of the titles in
this volume will be sent on request.

VOLUME 2.

. The Geology. of‘ Point Sal, by. Harold W. Fairbanks... .- =...
- On Some Pliocene Ostracoda from near Berkeley, by Frederick Chapman.................
- Note on Two Tertiary Faunas from the Rocks of the Southern Coast of Vancouver

Island, by J. C. Merriam.................-.- Bon ngetcswnfecececstenBeksangen dase tas Un ieee ee ee arr a:
. The Distribution of the Neocene Sea-urchins of Middle California, and Its Bearing

on the Classification of the Neocene Formations, by John C. Merriam
. The Geology of Point Reyes Peninsula, by F, M. Andersom...........22...2--22-22--ce--eee--eeee
. Some Aspects of Erosion in Relation to the Theory of the Peneplain, by W. S.

Cnr

11. Contributions to the Mineralogy of California, by Walter C. Blasdale...........0.
12. The Berkeley Hills. A Detail of Coast Range Geology, by Andrew C. Lawson and
Charles, Palache~ ...° 22s see.... 23. eee ae a een ae 2 eee

VOLUME 3.

1. The Quaternary of Southern California, by Oscar H. Hershey
2. Colemanite from Southern California, by Arthur S. Hakle
8. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by
Amrdrew ©. sTuawsort 2.0.22. 2cce5 cscs eect enrages aoe ere
4. Triassic Ichthyopterygia from California and Nevada, by John C. Merriam
6. The Igneous Rocks near Pajaro, by John A. Reid. ..........-ccce-ccececccceececteeceeneesoeeeceeneeeees
7. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller
3. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by
“Andrew Cy Tia wson.. ..2:\ceeinc--Bise-2- orci scence cece See ee semesters oe a
9) Palaicheite, by -Arthur.S. Balle: .22:. 202 tc cn nfs 05 aces eee =
10. Two New Species of Fossil Turtles from Oregon, by O. P. Hay.
11. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair.
Nos; 10 amd 17 im ome CO VOM .2eicsi a. re Gene onscreen me aac
12. New Ichthyosauria from the Upper Triassic of California, by John C. Merriam...
13. Spodumene from San Diego County, California, by Waldemar T. Schaller_...._....
14. The Pliocene and Quaternary Canidae of the Great Valley of California, by
ion Os Miererrayrnay 5 a ee ee pee E
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson...”
16. A Note-on the Fauna of the Lower Miocene in California, by John’C. Merriam...
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew ©.
We SOT. Fekete oc Pe ace ccs
18. A New Cestraciont Spine from the Lower Triassie of Idaho, by Herbert M. Eva
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmo
20. Euceratherium. a New Ungulate from the Quaternary Caves of California, b
William J. Sinclair and HB. Li. Furlong.-...---.--------2-:2------2s-e---nre eee 33
21. A New Marine Reptile from the Triassie of California, by John C. Merriam ..
22, The River Terraces of the Orleans Basin, California, by Oscar H. Hershey...

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 4, pp. 47-60, pl. 7 Issued October 10, 1912

THE NEOCENE SECTION AT KIRKER PASS
ON THE NORTH SIDE OF MOUNT
DIABLO

BRUCE L. CLARK

CONTENTS

PAGE

BTA GT. CHILI CT: Mag eres Oe sarees gas tes So anse vu scusee eccuscestatacassenessaseracdssesse:deceeee--2ccs 48
FN SGOT Call SVC VAC Wek osts 22. oc c2hc-ecce- aca: sacebeeevsctocssoeanteece=2-ssteubeciveacescessaieadeaacnesde 48
INIA © epee eee cere ee tes Sno caeeusaveserteeces snescesastacsace oeses :eieedcasecstneacetae=aaa 49
TeyeN beast He) MESO oes eee ee pe PP Pe ere 49
Slhallepe Term by ery eset eres osteo ee ces fe eases 2 sed ete uence cece davon e sesseescoaasee’ 49
Carbonaceous Shales and Sandstones .......2.....-2-.--:-::-0000ceeeeeeeee 50
Tuffaceous Shales and Sandstones .............2-.-2-----:0--2-:e-e0eeeeeeeeeeeeeeetee 50
TDF yUuNEY, (Ope Bf) oy oyemes NU o Sauer) Se ree ee eee 51
Sear, TERN) 0 Ka); <a ae er Soar POD EPO EET 52
Gren eralleel)i SC USS] OTimeeeesee ere ssree tes ener eer eee eee Ne reese hes needs S es seeeeecesete 52
Tape TD a SS ay eta Ne en 53
IMUM a Ot) WO Wer MOUVISION: 2..2.2206-..eccceeeccee coe cectceecacecSeeegucee se -ce--encsscte=eecaeces 54
[Oyo anesie TONSA apa ar eee err 55

TD EDULE, Cope LO eg oxene: IO at SuCoy al eee cee eee eee 56
LEVIES LOR aE se ee Se EO 57
AAT Lay each ge eee costes sae ee useeseecttve ses Ber ee Fa N ae hc aerate see a ets es 58
Ors G Rye a ee re eR 59
Generals SCChlON Gy cesereeterieretttres toa. soee eenseec sass a ee eee 59
Comparison with Section on South Side of Mt. Diablo —.......-..-.-.--.- 60

PS ELIMI Tay se re see eee cee se cn cua en ct ivatdoct se oleceeaeecs ueecesters eee 60

48 University of California Publications in Geology (Vou.7

INTRODUCTION

Mt. Diablo may be described as the core of an anticline which
is overturned and overthrust. The Franciscan series forms the
core of the mountain mass. Stratigraphically above this and
surrounding the mountain is a series of sedimentary formations,
ranging in order through the Knoxville (Jurassic ? to Creta-
ceous), Chico (Cretaceous), Martinez (Lower Eocene), Tejon
(Upper Eocene), Monterey (Lower Neocene), San Pablo (Middle
Neocene), and Pinole Tuff and Orindan (fresh-water formations
belonging to the Upper Neocene).

The beds described in this paper lie to the north of Mount
Diablo. The lowest of the Neocene beds are between six and
seven miles north of the main peak. The width of the section
described is about two miles, the outcrop, mapped, is about six
miles long. The general strike of the beds is about N 70° W; the
dip varies from 40° to 20° N E.

HistroricaL Review

The formations of the Mt. Diablo region were first described
by Whitney in 1865.1. In 1891 and again in 1898 Turner?
described the section more in detail, listing thirty-eight species
of marine invertebrates from the San Pablo on the north side
of the mountain, determined by J. C. Merriam.

In 1898 J. C. Merriam,* in his paper ‘‘The Neocene Sea
Urehins of Middle California,’’ described the San Pablo forma-
tion on San Pablo Bay, and correlated with it marine beds from
the vicinity of Mt. Diablo, deseribed as Phocene by Whitney
and Turner.

In 1909 C. E. Weaver, in his paper on the ‘‘Stratigraphy
and Palaeontology of the San Pablo formation in Middle Cal-
fornia,’’* gave a brief description of the San Pablo in the region

1 Geological Survey of California, vol. 1, pp. 31, 1865.

2 Bull. Geol. Soc. Amer., vol. 2, p. 383, 1898; Jour. Geol., vol. 6, pp.
443-449, 1898.

3 Univ. Calif. Publ., Bull. Dept. Geol. vol. 2, no. 4, pp. 109-118, 1898.
4Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, no. 16, pp. 243-269, 1909.

1912] Clark: Neocene Section at Kirker Pass 49

of Mount Diablo, listing forty-six species of marine invertebrates
from the beds on the north side of the mountain.

Both Whitney and Turner stated that there was apparently
a conformable sequence of formations from the top of the moun-
tain down, including Cretaceous, Eocene, Miocene, and Pliocene.
Since these papers were published, unconformities have been
reported between the Franciscan and the Knoxville, the Chico
and the Martinez, and the Martinez and the Tejon.°

MonrTEREY

Relation to Tejon.—The Monterey series forms the basal
member of the Neocene on the north side of Mount Diablo.
Between unquestionable Monterey and Tejon it has not as yet
been possible to draw a sharp line in this section.

A series of light brown to gray, micaceous, medium-coarse,
massive sandstones about 2000 feet in thickness which underlie
the clearly recognized Monterey is possibly the upward con-
tinuation of the Tejon, but so far no invertebrate fossils have
been found in them. Carbonaceous material, including leaves
and wood, is abundant in the upper part of this formation, and it
may be possible in the future to get good leaf collections that
will throw some light on the question of the age of these beds.
This zone is doubtfully referred to the Tejon but intensive coi-
lecting will be necessary before its age can be certainly deter-
mined.

Shale Member.—Above the micaceous sandstones just de-
scribed, and having the same dip and strike, appears a series
of shales, 150 to 200 feet in thickness, which quite certainly
represents the Monterey. The lowest member of this series is a
layer of white to hight buff, diatomaceous shale, which in some
localities contains considerable lenses of Lmestone. Just what
relation these shales have to the micaceous sandstones below is
not clear.

The Monterey shale of this section is in some localities thin-
bedded and slightly cherty. In other places it appears as a

5 Dickerson, R. E., Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, no. 8.
pp. 174-176, 1911.

50 University of California Publications in Geology |Vou.7

typical soft, light diatomaceous earth, such as is characteristic
of the Monterey in the many parts of the state. The lower part
of this shale band is very diatomaceous, the most common diatom
present is of the genus Coscinodiscus. The upper portion of this
member is more argillaceous and darker in color; diatoms are
absent and leaf impressions are quite common. Fish scales and
vertebrae are very common through the shale. Thus far, only
two species of invertebrates have been found in the shale; these
are Leda cahillensis Arnold, and an ophiuroid. The latter
appears to be a species found commonly in the Monterey near
Pinole Station on San Pablo Bay. These two species, taken with
the lithologic character of the shales, indicate that the beds are
Monterey.

Carbonaceous Shales and Sandstones—The shale just de-
seribed in the Kirker Creek section grades up into a series of
massive sandstones alternating with thin layers of shale and
clay. The sandstones are, for the most part, soft, of a medium-
coarse texture, massive, and vary from a gray to a yellow-
brown color. The shales and clays interbedded with the sand-
stones show considerable variation. Some of the layers of the
shale are black, others are nearly pure white. Carbonaceous
material, and impressions of leaves and wood are abundant in
many parts of this zone, and it appears that the beds were
deposited under estuarine or fresh-water conditions. The com-
bined thickness of this part of the section and the shale below
is roughly estimated as 1000 to 1200 feet.

Tuffaceous Shales and Sandstones.——Above the shales and
massive sandstones just described is a series of white ash-beds,
tuffaceous shales, and fine tuffaceous sandstones. These beds
in the vicinity of Kirker Creek have a thickness of about 400
feet. They were included by Turner and by Weaver in the
San Pablo formation. The results of the writer’s work show
that they belong to the Monterey, and lie unconformably below
the San Pablo.

The following is a section seen in these tuffaceous sandstones
and shales about one mile to the west of Kirker Creek (SW 14,
See. 3, R. 1 E, T. 2 8S). At the base of these beds, imme-
diately above the massive sandstones and shales already de-

1912] Clark: Neocene Section at Kirker Pass 51

scribed, is a thin layer of conglomerate. The conglomerate
grades up into a fine gray standstone, and a few feet above
the base is a thin layer of hard, dark-brown, conglomeratic sand-
stone, in which the following species of marine invertebrates
were found: Dosinia whitneyi, Mactra, n.sp., Nucula (Acila)
dalli, Marcia, cf. oregonensis, Solen rosaceus ?, Yoldia cooperi,
and Lunatia lewisi. Above this fossiliferous layer the sand-
stones grade up into a shaly and sometimes sandy tuff. These
beds are light gray to white in color. They are quite argillaceous
and crumble easily in the hand. Turner determined the tuff beds
of this horizon to be rhyolitie in composition, giving an analysis
of a specimen. The upper part of the series grades into a fine
sandstone which is quite fossiliferous. At several horizons im-
pressions of shells were found, and leaf impressions are com-
mon, especially toward the top. Lying unconformably on these
upper sandstones is the conglomerate of the basal San Pablo.

About one mile to the east of the section described above,
just to the east of the Kirker Creek, the sandstones at the top
of the Monterey are lacking, the upper part of the Monterey
being a white, fairly hard, shaly tuff, which is interbedded with
thin layers of fine to medium coarse, sometimes cross-bedded,
tuffaceous sandstones. As these tuffaceous beds are followed to
the east, they gradually thin out. About two and one-half miles
to the east of Kirker Creek, on the west side of Markley Canon,
only ten to fifteen feet of these shaly tuffs are seen just below
the San Pablo. On the east side of Markley Canon the tuffs
are absent, and here the San Pablo rests on a lower member
of the Monterey.

Fauna of Upper Monterey.—The beds deseribed above contain
the following fauna:

Cryptomya, cf. ovalis Conrad. Yoldia cooperi Gabb.
Dosinia whitneyi Gabb. Amphiura, sp. (?)

Modiolus multiradiatus Gabb. Calyptraea inornata Gabb.
Macoma nasuta Conrad. Caneellaria, sp. (7)

Mactra, n.sp. Cerithium, sp. (?)

Marcia, cf. oregonensis Conrad. Clavella, n.sp.

Nueula (Acila) dalli Arnold. Dentalium conradi (?) Dall.
Panopea generosa Gould. Dentalium petricola Dall.
Siliqua patula var. nuttalli Dixon. Lunatia lewisii Gould.

Solen rosaceus ? Carpenter.

52 University of California Publications in Geology [Vou.7

Of the species listed above, Dosinia whitneyi does not go
higher than the Monterey. Marcia, ef. oregonensis is one of
the most common forms in the Upper Monterey. Nucula (Acila)
dalli was first described from the San Lorenzo formation (Oli-
gocene). It occurs in the Miocene of Oregon and Washington.
Mactra, n.sp., is a form found in the Monterey near the town
of Pinole. Dentalium conradi? has been found only in the Lower
Miocene of this region. Dentalium petricola and Calyptraea in-
ornata are both common forms in the Monterey, and are not
found in the San Pablo. All of the others, excluding the new
species, are common forms in the Monterey.

San Paso

General Discussion.—Lying uneconformably above the Mon-
terey is the San Pablo. Previous writers have referred to these
beds as a formation; further study shows that they may well
be classed as a series. This is true, not only for the section to
be described in this paper, but apparently also for the type sec-
tion on San Pablo Bay, and for that on the south side of Mount
Diablo. Lithologically there are great variations in the beds,
which can be mapped as distinct units. On the south side of
Mount Diablo two distinct brackish water zones are found inter-
calated with marine beds, and at one locality, in Sycamore
Canon to the northeast of the town of Danville, an unconformity
is to be seen near the middle of the series. More work needs
to be done before it can be determined whether this uncon-
formity may be correlated with an unconformity on the north
side of the mountain, described in this paper. Whether either
of these unconformities is of more than local significance is not
yet determined. In the type section at San Pablo Bay a brackish
water zone also appears.

In the description of the San Pablo to the north of Mount
Diablo the writer has used the name ‘‘series’’ for these beds,
dividing them into two divisions, an Upper Division and a
Lower Division. The correlation of these divisions with the
upper and lower parts of the section on San Pablo Bay seems
justified on palaeontological evidence.

1912] Clark: Neocene Section at Kirker Pass 53

Lower Division.—That part of the San Pablo series which
is here designated as the Lower Division has a thickness, as
measured to the west of Kirker Creek, of about 350 feet. The
basal beds of the Lower Division in this vicinity are composed
of a layer of coarse conglomerate which is in places ten to
fifteen feet thick. The conglomerate consists of well-rounded
pebbles, some of which are three to four inches in diameter.
They are mostly made up of quartzites and volcanics, together
with some boulders of sandstone and shale. In the vicinity of
Markley Canon the basal beds consist of a layer of massive to
very much ecross-bedded, coarse to conglomeratic sandstone, that
stands out distinctly from the gray sandstones above, because of
its reddish-yellow color.

That the San Pablo series in this region rests unconformably
on the Monterey is shown by the following facts: (1) There is a
difference in strike and dip, and a slight irregularity in contact
between the two. (2) The basal beds of the series appear to rest
upon different members of the Monterey as one follows the line of
the strike. (3) Borers of the pholadid type were found along
this contact for a distance of over three miles. (4) Well-rounded
boulders lithologieally identical with the tuffaceous sandstones
and the shales of the Monterey below, are found in the basal con-
glomerate. These facts, together with the sharp lithological
break, leave no doubt as to the unconformable relationship of the
San Pablo and the Monterey.

In the vicinity of Kirker Creek the strike and dip of the
Monterey and the lower beds of the San Pablo are practically
the same, but to the east of Markley Canon there is a difference
in strike of from 10° to 15° and at least 5° difference in dip.
As pointed out above, the tuffaceous beds of the Upper Monterey
eradually wedge out in going east from Kirker Creek and disap-
pear at Markley Cafion, the basal beds of the San Pablo resting
on successively lower horizons of the Monterey.

The Lower Division of the San Pablo in general may be
characterized as made up of coarse, massive sandstones, con-
glomerates, and a very minor amount of finer material. Cross-
bedding is very evident at different horizons, and in some locali-
ties, especially to the west of Kirker Creek, considerable tuff

54 University of California Publications in Geology [Vou.7

is found mixed in with a very much eross-bedded sandstone.
The sandstones, especially toward the top, are vivianitic, but
are not so blue as those seen in the division above. The Lower
Division may be considered a shallow. water or strand deposit.

In the section to the west of Kirker Creek, about two hundred
and fifty feet above the base of the Lower Division and above
a medium fine to shaly, fossiliferous sandstone, is about a hun-
dred feet of coarse, angular-grained, tuffaceous, massive sand-
stone, which is quite conglomeratic at the base, and very much
cross-bedded toward the top. There is a strong suggestion that
these cross-bedded sandstones are terrestrial in origin, and are
possibly sand-dune material.

Fauna of Lower Division—The following species of inverte-
brates were obtained from the Lower Division of the San Pablo
series :

Astrodapsis tumidus Rémond. Olivella pedroana Conrad.
Seutella gabbi Rémond. Ostrea lurida Carpenter.
Astyris richthofeni Gabb. Ostrea titan Conrad.
Balanus, sp. Ostrea vespertina var. sequens ?
Calliostoma splendens Carpenter. Arnold,

Calyptraea costellata Conrad. Panopea estrellana Conrad.
Calyptraea filosa Gabb. Panopea generosa Gould.
Cardium corbis Martyn? Paphia staminea Conrad.
Cerithium, sp. ? Pecten pabloensis Conrad.
Chama pellucida Broderip. Pecten crassicardo Conrad.
Chionella neweomboniana Gabb. Pecten diseus Conrad.
Chione, sp. indet. Phacoides tenuisculpta Carpenter.
Corbicula, n.sp. Pholas, sp. ?

Crepidula rugosa Nuttalli. Platydon cancellatus Conrad.
Cryptomya ovalis Conrad. Pleurotoma, n.sp.?

Dosinea, n. s. Saxidomus nuttalli Conrad.
lattorina remondi Gabb. Schizodesma abscissa Gabb.
Littorina, sp. a. Siliqua patula var. nuttalli
Lunatia lewisii Gould. Conrad.

Macoma, n.sp.. Conrad. Solen, n. sp.

Metis alta Conrad. Spisula albaria Conrad.
Modiolus multiradiatus Gabb. Spisula catilliformis Conrad.
Mytilus coalingensis Arnold, n. var. Thais canaleulata Duclos.
Nassa mendica Gould. Tresus nuttalli Conrad.

Ocinebra lurida var. aspera Baird.

The most common species in the Lower Division of the San
Pablo series are: Metis alta, Mytilus coalingensis, n. var., Modiolus

1912] Clark: Neocene Section at Kirker Pass

multiradiatus, Ostrea titan, Saridomus nuttalli, Tresus nuttalli,
and Crepidula rugosa. No evidence of faunal zones was found
within the Lower Division of the San Pablo.

Upper Division.—Above the massive cross-bedded sandstones
in the Kirker Pass section there are several thin layers of hard,
dark-gray sandstones, which weather a rusty brown. These hard
layers cap one of the larger hills about one mile to the west of
Kirker Creek. These layers are lenticular and along the strike
in places grade into coneretionary sandstones. This zone is
very persistent and served as a basis for separation of the
lower division of the series from the upper. Impressions of
leaves and pieces of silicified weod are found in abundanee, both
above and below these hard layers. Turner,® in his paper on
‘The Geology of Mount Diablo,’’ reports the occurrence in this
zone, of fossil leaves of the following species, determined by

Lesquereux :

Diospyros virginiana, var. turneri, Laurus, cf. canariensis Heer (?)
Lx. Viburnum, ef. rugosus Pers. (?)

Magnolia ealifornica Lx. Vitis, sp. und.

Just below the hard layers of sandstone mentioned above
is a very marked irregular contact. This irregularity is seen
between coarse sandstones above and fine shaly sandstones below.
This contact was first called to the attention of the writer by
Mr. Graham Moody. The irregularity was traced for a distance
of nearly a mile. In some places there is as much as three to
four feet of relief. As far as could be determined, there was
no difference in dip and strike between the beds above and
below. That the irregularity is due to erosion, there can be no
doubt. The great abundance of leaves and silicified wood along
this zone has already been mentioned. Also along this horizon
there is a series of silicified trees that stand perpendicular to
the dip of the beds. In some eases indications of roots were
observed. One can hardly doubt that these stumps are in place.

To sum up, it may be said that an unconformity at this
horizon in the San Pablo series is shown: (1) by an irregular
contact; (2) by the great abundance of fossil wood and leaves

6 Bull. Geol. Soe. Amer., vol. 2, p. 497, 1891. Description of Leaves,
U. S. National Museum, vol. I, II, p. 35, 1889.

56 University of California Publications in Geology ([Vou.7

together with tree trunks standing at right angles to the dip;
(3) by the character of the deposits found along this zone; i.e.,
a very tuffaceous, angular-grained, cross-bedded sandstone.

In the section just referred to, immediately above the hard
layers of sandstone, there is a layer of medium-coarse, tuffaceous,
angular-grained, concretionary sandstone between ten and fif-
teen feet thick. This layer is very much cross-bedded, and, like
the cross-bedded sandstones below the hard layers, suggests
that they are sand-dune deposits. The tuffs in these sandstones
and the conglomerates above the basal beds of the Lower Division
were determined by Turner as andesiti¢ in origin.”

The Upper Division of the San Pablo series has a thickness
of about 250 feet ,and consist mainly of coarse to medium-fine,
bright-blue vivianitic sandstones, alternating with irregular
bands of light-buff clays. At a number of horizons these clays
have a thickness of several feet, and are thin-bedded and may be
classed as a shale. The sandstones are the predominating phase
of this division.

One of the noticeable features of this part of the series
is that the contacts between some of the clay layers and the
sandstones are slightly irregular, and the change from a sand-
stone to a clay is often very sharp. Another thing that is to
be noted is that leaf impressions and silicified wood are very
common at different horizons in both the sandstones and the
clays. It was in the upper part of this division that Turner’s
leaf collection of 1897 was obtained.*®

The following flora obtained by Turner from this horizon was
determined by Professor F. H. Knowlton:

Fern, probably Pteris, but very Castanea, sp. leaf.

fragmentary. Vaccinum, sp. single small leaf.
Populus, female catkin. Arbutus, numerous well-preserved
Alnus, fruits and leaves. leaves.

Fauna of Upper Division.—Good fossil localities in the Upper
Division of the San Pablo are very rare. Shells are found at
several horizons, but in nearly all cases they are very poorly

7 Jour. Geol., vol. 6, p. 497, 1898.
8 Idem., vol. 6, p. 498.

1912] Clark: Neocene Section at Kirker Pass 57

preserved. The following species have been collected from the
upper beds:

-Astrodapsis whitneyi Rémond. Mya japonica Gray.
Calliostoma splendens Carpenter, Pecten, n.sp.

n, var? Pecten discus Conrad.
Cardium quadrigenarium Conrad. Pecten pabloensis Conrad.
Corbicula californica Gabb. Platoydon cancellatus Conrad.
Cryptomya californica ? Conrad. Pseudocardium gabbi Rémond.
Cryptomya ovalis Conrad. Saxidomus nuttalli Conrad.
Littorina, n.sp., b. Solen sicarius Gould, n. var.
Littorina, n.sp., c. Calyptraea filosa Gabb.
Macoma, n.sp. Conrad, Trophon ponderosum Gabb.
Macoma secta Conrad. Zirphaea dentata Gabb.

Modiolus multiradiatus Gabb.

Faunal Zones.—Because of the meagerness of the fauna in
the Upper Division it may possibly seem premature to assume
the presence of two faunal zones in the San Pablo series
corresponding to the two divisions as described. It would seem
reasonable to suppose that the absence of certain species from
the upper beds that are found in the lower could be ae-
counted for by the larger representation of individuals in the
latter, but the absence of certain species in the lower beds
that are found in the upper would not indicate that this is the
correct explanation of the difference. Some indication of zonal
difference between the faunas of the upper and lower divisions
is found in the presence in the Upper Division of the follow-
ing species not known in the Lower Division: Astrodapsis whit-
neyi, Pseudocardium gabbi, Littorina, sp. b., Littorina, sp. c¢.,
Corbicula californica, and Trophon ponderosum. In the Upper
Division two new species of Littorina are found which are not
found in the Lower Division, while Littorina rémondi and Lit-
torina, sp. a are not found in the Upper Division. In the
Lower Division a new species of Corbicula is found which is
not found in the Upper, while Corbicula californica, so common
in the upper beds, has not been found in the Lower Division.

Practically the entire fauna of the San Pablo at Kirker Pass
belongs to shallow water. Quite a number of species, such
as Corbicula, Ostrea, and Littorina, are either fresh-water or
brackish-water forms.

58 University of California Publications in Geology {Vou.7

PINOLE TUFF

Lying unconformably above the Upper Division of the San
Pablo is a series of tuff beds. This unconformity is shown by
a marked, irregular contact with as much as ten to fifteen feet
relief, and a shght difference in dip and strike.

The thickness of these tuffs is about one hundred and fifty
feet. The basal bed of this series, as seen west of Kirker Creek,
is a layer of a white, massive tuff, three to four feet thick. The
beds immediately above the basal white layer are made up of
large angular fragments of light-gray to bluish pumice, which
are included in a matrix of rather ashy, reddish-brown material.
This ashy matrix gives a noticeably red color to the beds. Seat-
tered through these tuffs are angular fragments of voleanic rock,
which are undoubtedly voleanic ejectments thrown out with the
ash. These beds are massive and stand out as prominent layers
several feet in thickness.

In the vicinity of Markley Cafion, at the base of the Pinole
Tuff, is a layer of conglomerate, which contains subangular water-
worn boulders of basalt, two to three feet in diameter. These
coarse boulder-beds are overlain by coarse, thick layers of red-
dish tuff, which weathers out in prominent wall-like outcrops.

One mile and a quarter to the west of Kirker Creek a basalt
flow about four feet in thickness was found in these basal beds.
This is situated only a few feet above the contact, with the tuff
above and below. The rock shows a distinct flow structure, and
the upper surface is quite vesicular.

The upper members of the tuff beds lack the reddish color.
In some places they are nearly pure white, and have lenses of
cross-bedded gravels and sands mixed irregularly with them.
Turner determined these tuff beds to be rhyolitic in composi-
tion.

The tuff beds above the San Pablo at Kirker Pass have been
correlated provisionally with the Pinole Tuff seen on San Pablo
Bay, that to the north of Carquinez Straits, and that in the
vicinity of the town of Walnut Creek, first, because of their
stratigraphic position; second, because of their lithologic and

1912] Clark: Neocene Section at Kirker Pass 59

petrographic similarity. No fossils have been found in these
tuffs at Kirker Pass, and it is a question whether they are land
or water deposits.

ORINDAN

Above the Pinole Tuff is a series of light-yellow to gray,
medium-fine sandstones, and clays. In this region it is difficult
to get good outcrops in these beds, and the writer has given very
little attention to them. They are provisionally called Orindan,
chiefly because of their stratigraphic position. These beds have
been folded with all the other formations, and dip gently to
the northeast. They extend out into the valley, where they are
covered with terrace material.

GENERAL SECTION

GENERAL STATEMENT OF SECTION AS SEEN ABOUT ONE MILE TO THE WEST
oF KIRKER CREEK

Orindan Yellow sandstones and clays.

Tuff with gravel and sand.
Pinole Tuff 150 ft. Basalt flow.
Massive tuff beds.

with layers of clay. Estuarine deposits,
200 ft. :

Fossil wood zone, coarse, massive eross-
bedded sandstones 50 ft.

San Pablo

Bright blue vivianitic sandstones alternating
Upper Division 250 ft.

Coarse, massive, very much cross-bedded
sandstones. Eolian (?) deposits, 100 ft.

Medium to coarse grained fossiliferous sand-
stones, thin layers of fine and coarse con-
glomerate, tuffaceous cross-bedded sand-
stones, coarse gray conglomeratic fossil-
iferous sandstones and basal conglomerate,
250 ft.

San Pablo
Lower Division 350 ft.

leaves and thin layers of cross-bedded
sandstones, 400 ft.

Carbonaceous sandstones alternating with
shales and clays, 1000 ft.

Monterey 1600 ft.

= sandstones, shaly ash beds with

Diatomaceous shale, 200 ft.

60 University of California Publications in Geology [Vou.7

COMPARISON WITH SECTION ON SouTH SIDE oF Mr. DIABLO

The comparison of the Neocene beds on the north side of
the mountain with those on the south side is very interesting,
especially as regards the San Pablo series. The San Pablo on
the south side of the mountain has a thickness of about 2500
feet as against 600 feet on the north side. The lower beds on
the south side are more homogeneous than those on the north side
of the mountain. The Monterey on the south side lacks the car-
bonaceous shales and sandstones seen near the middle of the
series on the north side.

As a whole, it may be said that the Neocene on the north
side of the mountain is characterized in a greater degree by
strand conditions than are the deposits on the south side of the
mountain.

SUMMARY

Some of the more important results obtained in a study of
the Kirker Pass section are as follows: (1) The deposits of a
large part of the middle and upper Monterey had either a
fresh-water or an estuarine origin; (2) the fauna above and below
the estuarine beds of the Monterey series is Lower Neocene in
age; (3) a well-marked unconformity exists between the Mon-
terey and the San Pablo; (4) the San Pablo is to be classed as
a series rather than as a formation; (5) the deposits of the San
Pablo at Kirker Pass are distinctly littoral, grading from
marine to brackish-water conditions; (6) in the middle of the
San Pablo series there are evidences of land conditions as shown
by an irregular contact, fossil wood, leaf impressions, and the
character of the deposits; (7) the Pinole Tuff hes unconformably
on the San Pablo.

= Mi Seettic =o
y :
° 1 :
: (6 l) ; x a
N= CS) PA IID) >ar/ (NX NQ)
, Pinole y

irk Tor dan; Tp Tuff; Tsp, San Pa
ffae hale, L, diatomaceou

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VOLUME 2.

1, The Geology of Point Sal, by Harold W. Fairbanks........0 522. = =e
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3. Note on Two Tertiary Faunas from es Rocks of the Southern Coast of Vancouver
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4, The Distribution of the Neocene Bear urchins of Middle California, and Its Bowne
on the Classification of the Neocene Formations. by John C. Merriam
5. The Geology of Point Reyes Peninsula, by F. M. Anderson... 10-22
6. Some Aspects of Erosion in Relation to the Theory of the Peneplain, by W. S.
Tampier Smith” 22.08.20. ccc once, etietes Sonnet ates cnciee sland easee ganar san suet
7. A Topographie Study of the Islands of Southern California, by W. 8. Tangier Smith
8. The Geology of the Central Portion of the Isthmus of Panama, by Oscar H. Hershey 31
9. A Contribution to the Geology of the John Day Basin, by John C. Merriam
10. Mineralogical Notes, by Arthur S, Makle..........22.0 is. Loc eee
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12. The Berkeley Hills. A Detail of Coast Range Geology, by Andrew c. Lawson and —
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1. The Quaternary of Southern California, by Oscar H. Hershey ........2--..20-.22-ess eee
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3. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by

Andrew (@.~ Lev wS0n no .-- 228-225 spec ccgnvar nse seen soa gen sae tee ane veatomne te one
4. Triassic Ichthyopterygia from California and Nevada, by John C. Merriam... 5
6. The Igneous Rocks near Pajaro, by John A. Reid... --.-2--cse--ccececcceneetececeececemeeceeneneceess
7. Minerals from Leona Heights, Alameda Co., California, by Waldemar 7. Schaller
8. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by

Andrew. Cy Lawson 22. see es sco Se aa ree
9. Palacheite, by Arthur S. Hakles._....2.. oie. -ee seep eeeee eee eo
10. Two New Species of Fossil Turtles from Oregon, by O. P. Hay.

11. A New Tortoise from the Auriferous Gravels of California, by W, J- Sinclair,

Nos.-10 and 11. in one Covers... 52.2228 Ree oe oe ee

12. New Ichthyosauria from the Upper Triassie of California, by John C. Merriam

13. Spodumene from San Diego County, California, by Waldemar T. Schaller...

14. The Pliocene and Quaternary Canidae of the Great Valley of Californ a, by
John C. Merriam ay

15, The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson...

16. A Note on the Fauna of the Lower Miocene in California, by John C. Merr

17. The Orbicular Gabbro at Dehesa; San Diego County, California, by Andrew C.

SD WAS(0) « Pee eee Dar se teseeceen one oe, Bea oe Sp rsbere > aaemeeeen she. ceeaeee See were eos

18. A New Cestraciont Spine from the Lower Triassie of Idaho, by Herbe

19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover x

20. Euceratherium. a New Ungulate from the Quaternary Caves of California,

William J. Sinclair and EB. L. Furlong... 2-22. --ce-c-scenee seen eee nace ecnereeeneceneemneneenes e

21. A New Marine Reptile from the Triassic of California, by John G. Merriam

2°. The River Terraces of the Orleans Basin, California, by Oscar H. Be oe ;

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Vol. 7, No. 5, pp. 61-115 Issued October 12, 1912

CONTRIBUTIONS TO AVIAN PALAEONTOL-

OGY FROM THE PACIFIC COAST
OF NORTH AMERICA

LOYE HOLMES MILLER

CONTENTS

TETaU TREO GAY ae a eC
ANGI TAW OA NGO EN 01S eee
Significance of Osteological Characters in Ornithology .....................
Review of the Literature ........ Sa ea eet ee ee eee
AVirayberralpaiyalil aol Chester cence ete las eee ces fee eens pee nabes Son factcayebeadandsovssevseseseeces
OI Cem el Ha UM anc cs ees se tanec ve Sore Souisvnca cncncnedecvieatececcepeistcesseceteieSi oats
Miocene Fauna ................-....... ee ar
HATEISCO CONC eM AUN Ae <2... -.2 cote ccc seeecsenscbce lbs. sfesscceesssesecceracdescoetssedstuceaéessctcnctescete
VEEL CORRES) Se SLOPE
Seana CeO OR Sh a a
HEV AWAV CTC A Vis sofa cre Sesc levis ieee set csacdesstese<tefeee tes g Seee Sate E sates cacgt susteuacstecceuscsestate
EVENING Op Uae STC Ap a tavtsan «ce she ces ceseoce 2020 feces scpdey sees ia esssdacesceseaedsesorstacdessiecesse25=
BELO SSM UC perce e te cee ae tree cae ote ac seca oda rev Sestetssyiaetsvacssaeesiiasas¥escteneeis
TRKOCKSYay DEAE ASS HOLLEN OYE one mE
Present Physiographie and Geographic Relations of the West-American
Regions in which Fossil Avian Remains are known ........................
Relation of Pleistocene Faunas to those of the Present Day ..............
DistributionvobsthesCathartidae ses. acces ee ceen dest tee eee tenceet ee ee
Distribution of the Palconidae <...cc2.-....ccccccesescetecneceseeecceeseevedeesen-s- Soe
PATOMALTES Ime TStId DUGVO Di 2-ceu2 oes: 22sce se ctecesaselase-eeeessetesedsyoceesee -deesdeescusee eee
Possible Influences Conditioning Present Distribution of Certain
(SOUS eee eset cn ccec ec ees tc eee ede ve ten cu cvbeteeviveonsibiecseus iecectsceiecpessenenteteateiececeee?

Bird Remains as Indicators of Climatic Conditions
Time Relations as Suggested by a Study of Bird Remains ............
Wauisesmotmlxtinetion of Binds. .hic.ceccec...ies.2.tscdesendecoceseesoccseusenschanceceancs
Tabular Arrangement of West-American Pleistocene Avifaunas ............

Bibliography of Pacific Coast Fossil Avifaunas —.......-2....----

62 University of California Publications in Geology [Vou.7

INTRODUCTION

When the vertebrate palaeontologist turns his attention to
the group Aves as represented in North America, especially if
he be confronted with the problems represented by a considerable
mass of unassorted material, he cannot but feel that he pushes
out into almost uncharted waters, a wide sea where the few
islands recorded by previous explorers—djislands too often
shrouded in mist—may perhaps never appear upon his horizon.
The scarcity of previous record, the wide separation in place of
the bird-bearing deposits, coupled with the inadequacy of descrip-
tions and the poverty of museums in collections of Recent avian
osteology—all these are factors which conspire to give the student
entering upon such an undertaking the feeling that he stands
or falls unto himself. In full cognizance of these conditions the
present paper is undertaken. Its dual purpose is the recording
of certain facts but recently made known in this interesting field,
and the correlating, insofar as this is possible, of the results thus
far attained.

ACKNOWLEDGMENTS

Study of the University of California collections was taken
up at the invitation of Professor John C. Merriam, head of
the Department of Palaeontology of that institution, and to his
unstinted aid, encouragement, and advice much of what value
this study may possess is here freely ascribed. Grateful acknowl-
edgement is also made to Messrs. Joseph Grinnell and H. 8.
Swarth of the California Museum of Vertebrate Zoology for
information cheerfully furnished on many Recent species and
for the loan of osteological material. Specimens of great interest
and value were loaned or donated by Dr. F. A. Lucas, Dr. A.
Smith-Woodward, Dr. F. C. Clark, Dr. C. O. Esterly, Mr. E. J.
Fischer, and Mr. J. Z. Gilbert. The very generous attitude taken
by Madam Ida Hanecock-Ross and the associated owners of
Rancho La Brea in issuing permits to excavate the asphalt de-
posits made possible the assembling of much valuable material
essential to the work. Through the personal efforts of Dr. J. C.
Hawver, of Auburn, California, as well as by the very cordial

1912] Miller: Pacific Coast Avian Palaeontology 63

assistance extended by him to the author, our knowledge of the
Hawver Cave deposits has been greatly advanced. To each of
these persons the author’s sincere thanks are extended.

SIGNIFICANCE OF OSTEOLOGICAL CHARACTERS IN ORNITHOLOGY

In a zoological group of such narrow delineation and of such
great homogeneity as the class-Aves, where separation into the
various systematic divisions is based upon relatively small varia-
tions and where these variations affect structures not preserved
for study, a considerable degree of care must be exercised when
interpreting discoveries of the palaeontologist in terms of modern
systematic zoology. The difference noticeable to a worker in the
former field should in many eases be multiplied by a very large
factor upon their transposal to the latter. Degrees of diver-
gence which to the palaeontologist seem of no more than specific
rank might, by the worker in systematic ornithology, having
also various intricate details of color-pattern or feather struc-
ture at his disposal, be found correlated with differences of
more than generic importance. The distinction upon osteological
characters of many well-defined species of Recent birds is a
matter requiring complete skeletons of individuals of known sex;
even then conclusions are often in question. It is here con-
ceeded as possible under these conditions, and considering the
fact that most of the fossil specimens are not capable of articula-
tion, that many of the fossil specimens ascribed to living species
might, if all characters were determinable, be separated as dis-
tinct forms. It must be remembered also that within certain
groups the osteological differences between species is greater than
in others. The feather of the bird is an epidermal structure
which reflects with sensitiveness the activities of the animal and
is plastic as a specific character under the influences of environ-
mental changes. It is a proper basis of specific distinction, yet
it is almost never preserved in the fossil state. The tooth of
the mammal, likewise an epidermal structure and highly repre-
sentative of the animal’s activities, is a character used in com-
mon by the palaeontologist and the modern systematist. Zoology
and palaeontology are then much more nearly upon the same

64 University of Califorma Publications in Geology [Vou.7

basis in the determination of mammals than is the ease with
birds. Recognizing this principle, the author of this paper has
proceeded with perhaps more than necessary caution in the an-
nouncement of new species, preferring to err on the part of
conservatism rather than to confuse the literature of the subject
by making assertions which must later be modified; and there are
in the collections studied many specimens regarding which fur-
ther knowledge is considered necessary before problems upon
which they may throw light can be attacked in more than a
speculative way.

REVIEW OF THE LITERATURE

Since the epoch-making discoveries by Marsh which added
so materially to our conception of the ancestry of birds, con-
tributions to knowledge in the field of avian palaeontology have
been few as compared with the rapid enlargement of our under-
standing of the other vertebrate groups. Bird remains on the
?acifie Coast are mainly from Pleistocene strata; thus there is
eliminated the probability of shedding much new heht upon the
ancestry of certain groups in which our interest is so acutely
focused, for example the Stereornithes. Discoveries recently
made have contributed to science chiefly in two ways, first in
giving us an appreciation of the relative antiquity of the main
groups into which birds are divided; and, second, in adding to
our knowledge of the geographical distribution of these groups.
The consideration of geographical distribution is but begun when
we record the range of the Recent species. Determination of
the factors which have led to such distribution, if we aspire to
something better than mere speculation, must look to the record
of previous conditions as brought to light through palaeontol-
ogical inquiry.

The fossil-bearing rocks of the Pacifie Coast of North
America, while rich in the remains of mammals and reptiles,
have until recently yielded but little information concerning the
avian group.

In 1878, Cope! described three new species of birds from
the Equus Beds of Oregon. All three species belong to genera

1 Cope, E. D., Bull. U. S. G. S., Terr., iv, No. 2, May 3, 1878.

1912] Miller: Pacific Coast Avian Palaeontology 65

still inhabiting the region; thus their importance is limited to
the evidence they furnish of the division of a genus into several
coordinate species.

In 1892, Shufeldt? published the results of an extended study
of the Cope and the Condon collections of birds from this same
region. In this very thorough discussion there are fifty species
enumerated, fourteen of which are described as new. The entire
number, with the exception of the gallinaceous Paleotetrix gilli,
are assigned to existing genera. Phoenicopterus is the only
existing genus recorded which is foreign to the region at present.

In 1894, Cope*® deseribed a single species, Cyphornis magnus,
from a formation in Vancouver, British Columbia, which he
placed with some reservation in the Eocene, but which was later
considered by others to be Oligocene. The species is considered
as pelecanid in its affinities but generically distinet from any
form now living.

Lueas, in 1901,* described a new genus and species of diver,
Mancalla californiensis, from a formation at Los Angeles, Cali-
fornia. From the associated invertebrate fauna, this species is
considered by Dall to be of upper Miocene or lower Pliocene age.

As a result of the preliminary study put upon the University
of California collections by the present writer, there have ap-
peared a series of short papers dealing with a number of species
from Fossil Lake, Oregon, and from the caverns and the asphalt
beds of California. While these papers record one unique form,
Teratornis, of unusual interest, the main value of the contribu-
tions, like that of Shufeldt’s, les in the light shed upon the
former distribution of families of birds still living.’

2 Shufeldt, R. W., Journ. Acad. Nat. Sei. Phila., Ser. 2, No. 9, p. 389,
1892.

3 Cope, E. D., Journ. Acad. Nat. Sei. Phila., Ser. 2, No. 9, p. 449, 1894.
4 Lucas, F. A., Proe., U. S. Nat. Mus., vol. 24, p. 133, 1901.

5 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geol., vols. 5-6 passim,
1909-11.

66 University of California Publications in Geology [Vou.7
MAaAtTertAL AVAILABLE

The material upon which studies of the west coast fossil
birds have been based has been collected from nine different
horizons, summarized as follows:

OLIGOCENE
Vancouver, B.C. One species (a single specimen).

MIOCENE
Virgin Valley Beds, Virgin Valley, Nevada. One species.
Los Angeles, California. One species (a single specimen).

PLEISTOCENE
Potter Creck Cave, California. Sixteen species.
Samwel Cave, California. Nineteen species.
Hawver Cave, California. Twelve species.
Rodeo Pleistocene, California. One species (a single specimen).
Rancho La Brea, California. Forty-nine species.
Fossil Lake, Oregon. Fifty-three species.

The avian collections assembled at the University of Cali-
fornia represent seven of these localities. One of the seven is
identical with that studied by Cope and Shufeldt, namely, the
Fossil Lake region of Oregon. The remaining six collections, so
far as known to the writer, have not been studied previous to
the assumption of the task here in part recorded. Three or
four hundred specimens represent the bird remains from the
caves, and three or four thousand have been taken from the
asphalt at Rancho La Brea.

So far as can be learned, the Oligocene horizon yielding
Cyphornis to Cope, and the Miocene, from which Lucas described
Mancalla, have yielded no other avian fossils.

OLIGOCENE FAUNA

Cyphornis magnus Cope is the only species known to the
coast from strata of possibly so great age. The form was de-
seribed by Cope® from a single specimen, the proximal end of
a tarsometatarsus, the property of the Geological Survey of
Canada. The osteological characters displayed by the speci-
men are such as to have led Cope to assign the species
with some reserve to the family Pelecanidae. Interest
centers to some extent in a combination of the two characters,

6 Cope, E. D., Journ. Acad. Nat. Sci., Phila., Ser. 2, No. 9, p. 449, 1894.

Bikes te em

1912] Miller: Pacific Coast Avian Palaeontology 67

large size and high degree of pneumaticity. The latter character
was considered by the author of the species as indicating the
bird’s ability to fly. If such conclusion be true, the species, since
the tarsometatarsus equaled in size that of the rhea, must be
considered as the largest known flying bird.

It may not be out of place here to consider the propriety of
Cope’s position regarding the relation of pneumaticity to the
power of flight. Let it be conceded that Cyphornis belonged to
the Pelecanidae, birds of large size which are possessed of a
high degree of pneumaticity. We may then ask if the char-
acter pneumaticity necessarily became vestigial or disappeared
with the loss of ability to fly resulting from increased size. The
development of such a character as gigantism might be a matter
of comparatively short time, while the persistence of the char-
acter pneumaticity might be very tenaceous. An instructive case
in point is that of Geococcyx, a cuckoo of terrestrial habit whose
powers of flight have been almost entirely sacrificed. The pee-
toral arch in this bird is an absurdly weak structure, while
there is an accompanying accentuated development of the pos-
terior limb region. Despite this inversion of the appendicular
parts, the skeleton remains highly pneumatic. It seems well
within the range of possibility that Cyphornis should have
gained its large size by a rapid specialzation—a tendeney run
riot under certain conditions not adverse to it—and yet this
specialization cost the bird its power of flight without blotting
out the character of pneumaticity.

MioceENE FAUNA

Mancalla californiensis Lueas, from the upper Miocene of
Los Angeles, California, is described by Lucas‘? as being much
like the Recent species of murre (Uria troille) of that region, but:
more highly specialized in that it was probably without the power
of flight. The single specimen known consists of the major part
of the left humerus of a bird about the size of the recently
extinct great auk (Plaurus impennis). Interest in this discoy-
ery lies largely in the strong similarity of the bird to Recent

7 Lueas, F A., Proc. U. 8. Nat. Mus., vol. 24, p. 133, 1901.

68 University of California Publications in Geology (Vou.7

forins, in its flightless character suggesting to the author of the
species an insular breeding-ground free from enemies, and
finally in the fact that the accompanying mollusean fauna in-
dicates a climate cooler than that which characterizes the region

at present. It is regretable that a larger number of species was—

not discovered in the same horizon.

PLEISTOCENE FAUNA

Potter Creek Cave.—-Potter Creek Cave® takes its mame
from its location on Potter Creek, about one mile east of Baird,
a station of the U. S. Bureau of Fisheries on the McCloud River
in Shasta County, California. The locality les at present in
the lower Transition zone at an elevation of 1500 feet above the
sea. The surrounding country is well timbered with conifers,
oaks, and maples in the main, and with lower serub forming
thickets in less favorable exposure. Topographically the region
is rendered rather rough by numerous small tributaries of the

MeCloud River cutting through the Baird Shales, and the '

MeCloud Limestones, to form cafons with abrupt slopes and
much dissected ridges. The cave occupies at present a position
800 feet above the McCloud River, only slightly over a mile away.

According to the observations of Sinelair, the river flowed
during the formation of the cavern deposits at approximately
the level of the cave floor. The lowering of the river bed and
the backward cutting of tributary streams brought about more
rapid drainage of the country to either side of the cave, less
water entered the fissure, and cave-cutting ceased. Openings
were formed later in the roof of the cave by surface erosion,
thus permitting the entrance of clay, rock fragments, broken
bones and possibly of live animals. Subsequent uplift increased
the cutting by streams in the region, and Potter Creek cut
down through one of the galleries, thus forming the present cave
entrance.

There were two or three of these periods of uplift as deter-
mined by Sinclair which changed the character of the country
from one of moderate relief to one of mountainous aspect dis-

8 See Sinclair, W. J., Univ. Calif. Publ. Am. Arch. Ethn., vol. 2, pp.
1-27, 1904.

‘_

1912] Miller: Pacifie Coast Avian Palaeontology 69

sected by river canons. The indications are that the actual
elevation at present is considerably greater than that during the
deposition of the bone-bearing material. Certainly the relation
of the cave to the river level has changed in the neighborhood of
eight hundred feet. There is no evidence of a later subsidence
noted, so we may assume that the conditions during the period
of deposition were more like those at Rancho La Brea than they
are at present, i.e., less abrupt elevation and a smoother top-
ography. The presence of Dendragapus in the cave deposits is
an indication, however, that conditions were not identical in
the two localities.

A very interesting description of the various chambers and
galleries of the cavern is given in Sinelair’s paper. The fossil-
bearing matrix represents the accumulation on the floors of the
chambers and pockets in the form of fans of detritus, admitted
doubtless through old chimney-like chutes now entirely blocked
by limestone accretions and washed debris. These fans of ac-
cumulated material were encrusted, and in some instances
cemented, by stalagmitie deposits so that blasting had to be re-
sorted to in places.

The remains are in most cases entirely dissociated. Sinclair
notes the finding of a few skeletons in their proper anatomical
relations, such as those of a squirrel, a woodrat, a snake, and a
bat. These are all animals which would go into caves of their
own accord and after death fall upon the floors of the caverns.
_ No ease of bird skeletons in any degree associated is to be found.
The bones have entirely lost their organic matter and appear
almost as though ealeined. Perfect bones of the smaller verte-
brates are rare. In most cases fracture has occurred and in
many the articular surfaces have been injured, either on account
of the delicacy of the cancellated bone in that region, or because
the presence of articular cartilages tempted the appetites of
onawing forms. Weathering and cracking due to exposure on
the surface is the only reasonable explanation of the imperfec-
tions of some specimens.

Sinelair suggests three methods of possible introduction of
animal remains into the eave. Washing by rills which carried
bones from the surface down by way of the nearly vertical chim-

70 University of California Publicttions in Geology [Vou.7

neys seems a very probable method. These open chimneys may
have acted as pitfalls into which animals blundered in passing
over the surface. Again, predatory forms may have carried
their prey into the mouths of the caverns whence the accumulated
bones were washed, or carried by woodrats, into the more remote
recesses. This last method seems to the present author the
most probable means of introduction of such forms as the
anserines among birds. Falco peregrinus, whose remains also
occur in the deposits, is a large and powerful hawk which
habitually resorted to such places to nest. About the entrances
to their nesting crevices today one commonly finds the ac-
cumulated bones of a great variety of vertebrates brought as
prey. Their predilection for the anserines has given these birds
their common name of duck hawk.

Sinclair records the following list of vertebrates from the
Potter Creek Cave deposits, marking extinet species with an
asterisk:

SincLairR’s List OF SPECIES FROM POTTER CREEK CAVE

*Arctotherium simum Cope.

*Ursus, n. sp.

*Felis, n. sp.

Felis, near hippolestes Merriam,
OSH,

Lynx fasciatus Rafinesque.

Lynx fasciatus, n. subsp. (?)

Urocyon townsendi Merriam, C. H.

Vulpes cascadensis Merriam, C. H.

*Canis indianensis Leidy.

*Taxidea, n. sp.

Bassariscus raptor Baird.

Mephitis occidentalis Baird.

*Spilogale, n. sp.

Putorius arizonensis Mearns.

Arctomys, sp.

Sciurus hudsonicus albolimbatus

Allen.

Sciuropterus klamathensis Mer-
iabewooy, (O}, lake

Spermophilus douglasi Richard-
son.

Eutamias senex (?) Allen.

* Species marked with the asterisk

longer represented in the region.

Callospermophilus chrysodeirus
Merriam, C. H.

Lepus californicus Gray.

Lepus klamathensis Merriam, C.
H.

Lepus, near auduboni Baird.

Lepus, sp.

*Teonoma, n. sp.

Neotoma fuscipes Baird.

Microtus californicus Peale.

*Thomomys, n. sp.

Thomomys leucodon Merriam, C.
H.

Thomomys monticola Allen

*Aplodontia major, n. subsp.

Scapanus ecalifornicus (?) Ayres.

Antrozous pallidus Merriam, C. H.

*Platygonus (?) sp.

Odocoileus, sp. a.

Odocoileus, sp. b.

Haplocerus montanus Ord.

*Euceratherium collinum Sinclair
and Furlong.

(*) are either extinct or are no

1912] Miller: Pacific Coast Avian Palaeontology 71

*Bison, sp. *Equus occidentalis Leidy.

*Camelid. *Equus pacificus Leidy.

*Megalonyx wheatleyi (?) Cope. Crotalus, sp.

*Megalonyx jeffersonii (?) Har- Mylopharadon conocephalus Baird
lan. and Gerard.

*Megalonyx, n. sp. Ptychocheilus (?) grandis (?)

*Megalonyx, sp. (Ayres).

*Mastodon americanus Kerr. Acipenser medirostris (?) Ayres.

*Elephas primigenius Blumb.

To this list of species published by Sinclair, the studies of the
present author® would add the following birds:

SPECIES OF BIRDS FROM POTTER CREEK CAVE

Branta canadensis (Linnaeus). *Catharista shastensis Miller.
Oreortyx picta (Douglas). Buteo borealis (Gmelin).
Dendragapus obsecurus (Say). Faleo peregrinus Tunstall.
*Bonasa umbellus (Linnaeus). Falco sparverius Linnaeus
Indeterminate odontophorid. Otus asio (Linnaeus).
*Meleagris, sp. *Bubo sinclairi Miller.
*Gymnogyps amplus Miller. Colaptes cafer (Gmelin).
Cathartes aura (Linnaeus). Corvus brachyrhynchos Brehm.

* Species marked with the asterisk (*) are either extinct or are no

longer represented in the region.

Samwel Cave-—Samwel Cave was explored by E. L. Fur-
long, then of the University of California, who published an
account of his work two years after the appearance of Sinclair’s
paper on the Potter Creek Cave. Furlong’s account’ pictures
a cavern not essentially different from that deseribed by Sin-
clair. The conditions of interment seem to have been somewhat
different, however, since there occurred a number of entire skele-
tons of large and small carnivores and one form of ungulate,
Preptoceras, which were preserved without fracture of the bones
and in the proper anatomical relation. Furlong reaches the
conclusion that the cavern was used as a lair by such forms as
the bear and the cougar. To this lair the bodies of larger
ungulates like Huceratherium and Preptoceras were dragged as
prey. Some of the carcasses were left almost entire while others
were torn to pieces and the bones more or less broken by the

9 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 385, 1911.
10 Furlong, E. L., Am. Journ. Sci., vol. 22, pp. 235-247, Sept., 1906.

{2 University of California Publications in Geology [Vou.7

teeth of the captor. The suggestion is also made that the cavern
may have been used as a den for hibernation by various ursines,
even as other caverns in the region are known to be used by
bears of today.

No specimen of bird skeleton was found with bones in proper
place, so the probability is that the remains representing this
class were introduced largely as in the ease of the Potter Creek
Cave specimens. Some essential difference must have existed,
however, since the relation in numbers of the different species is
so different in the two localities. The Cathartiformes appear in
Potter Creek Cave represented by forty-five specimens distri-
buted over three species. In Samwel Cave there appear but six
specimens possibly assignable to the group. alco peregrinus,
represented in the former cave by four specimens, is wanting in
the latter. The owls are represented by five specimens in the
former and eleven in the latter, the grouse by thirty-four in
the former as against one hundred and twenty-four in the
latter.

This difference of faunal proportions is perhaps most readily
explained by the probable difference between the original open-
ines of the caves. Let it be conceded that, as suggested by the
respective authors, Potter Creek Cave opened by a relatively
small chimney or two on the surface of the Pleistocene hillside
and that Samwel Cave opened by a large chamber, the first part
of which ran more nearly horizontally. Vultures, ravens, and the
peregrine faleon nest in small cavities in rocky cliffs out of the
way of small predatory mammals like the raccoons and the
weasels. Their bones and those of their prey would accumulate
in these pockets and eventually find their way into deeper re-
cesses through fissures or chutes as described by Sinclair. The
owls, however, resort to large open-mouthed caves to roost during
much of the year, which fact would account for their greater
abundance in Samwel Cave. Raccoons were found in abundance
by Furlong as entire skeletons on the floor of Samwel Cave, thus
suggesting that these animals frequented the place as a lair.
The ground-dwelling birds, their natural prey, thus come to
form a large proportion of the avian remains in these deposits.
Procyonid forms are not listed by Sinclair from Potter Creek

1912] Miller: Pacific Coast Avian Palaeontology We

Cave. They were either absent from the region or did not fre-
quent the vicinity of the cave mouth. It seems not improbable
that these small carnivores had a distinct relation to the num-
ber of gallinaceous bird remains to become entombed in the
various cave deposits.

The following list of mammals is recorded by Furlong from
the Samwel Cave:

FUuRLONG’S List OF SPECIES FROM SAMWEL CAVE

Ursus americanus Pallas. Lepus, sp.
Ursus, n. sp. Thomomys monticola Allen.
Ursus, sp. Thomomys, sp.
Vulpes, sp. Microtus, sp.
Uroeyon townsendi Merriam, C. H. Neotoma fuscipes, Baird.
Procyon, near lotor Linn. Neotoma, sp.
Putorius arizonensis Mearns. Citellus douglasi Richardson.
Mephitis occidentalis Baird. Sciurus, sp.
Mustela, sp. Euceratherium collinum Sinclair
Felis, near hippolestes Merriam, C. and Furlong.

H. Preptoceras sinclairi Furlong.
Aplodontia, near major Merriam, Haplocerus, sp.

C. H. Odocoileus, sp. a.
Aplodontia rufa Rafinesque. Odocoileus, sp. b.
Erethizon epixanthus Brandt. Equus oceidentalis Leidy.
Aretomys, sp. Elephas, sp.
Lepus auduboni Baird. Megalonyx, sp.

SPECIES OF BIRDS FROM SAMWEL CAVE.

Indeterminate anserine a. Faleo sparverius Linnaeus.
Indeterminate anserine b. Asio wilsonianus (Lesson).
Indeterminate anserine e. Bubo virginianus (Gmelin).
Oreortyx picta (Douglas). *Bubo sinclairi Miller.
Indeterminate odontophorid. Glaucidium gnoma Wagler.
*Gymnogyps amplus Miller. *Micropallas whitneyi (J. G.
Cathartes aura (Linnaeus). Cooper).

*Catharista shastensis Miller. Colaptes eafer (Gmelin).
Accipiter velox (Wilson). Cyanocitta stelleri (Gmelin).

Buteo swainsoni Bonaparte?

* Species of birds marked with the asterisk (*) are extinct or else
foreign to the locality.

Hawver Cave.—Hawver Cave is now located in the same
faunal zone as the caves previously discussed and at about the
same elevation, though some two degrees to the southward. The

74 University of California Publications in Geology (Vou.7

formation of the cave is essentially the same except that the
work of solution is still probably going on to some extent. The
method of entombment of the organic remains appeared to Fur-
long to be the same as that acting in the ease of Potter Creek
Cave, i.e., the washing in of surface material by the action of
streamlets.

The presence of Megalonyx and Equus indicate the Pleisto-
cene age of the bone-bearing deposits in the fissure. There ap-
pear no remains of the large ungulates Huceratheriwm and
Prevtoceras to correspond with the deposits of the Shasta caves,
but this condition may be more apparent than real, since but
a limited amount of work was done in the cave before the level
of the water in some of the passages rose to a point so high that
access to the main bone-bearing chambers was prevented.

But twelve species of birds are represented in the collections
from this eave. Four of these are no longer represented in the
region. The fact that the cave is still open and that changes due
to the action of water are still going on lends a feeling of uncer-
tainty as to the exact age of any specimen. The association in
loose material of remains which are unquestionably Pleistocene
in origin with others representing still existing species -is no
cuaranty of the age of the latter. There is continually going
on a measure of differential motion in some of the debris ac-
cumulated, which would possibly mingle fragments deposited
at quite different times. Solution, shifting and re-cementing
may have recurred several times although the excellent state of
preservation of most of the bones would militate against the idea
that a great deal of such movement had taken place.

The few mammals thus far identified from Hawver Cave are
listed as follows:

Equus occidentalis (?) Leidy. Megalonyx, sp.
Aplodontia, sp. Felis hippolestes Merriam, C. H.

| ined

=]
On

1912] Miller: Pacific Coast Avian Palaeontology

List oF Birrps FROM HAWVER CAVE.

*Nettion carolinense (Gmelin). *Geranoaétus melanoleucus Auct.?
*Oreortyx picta (Douglas). *Colaptes cafer (Gmelin).
*Lophortyx californica (Shaw). *Cyanocitta stelleri (Gmelin).
*Meleagris, sp. *Corvus corax Linnaeus.
*Cathartes aura (Linnaeus). *Euphagus eyanocephalus (Wag-
*Catharista shastensis Miller. ler).
*Archibuteo ferrugineus (Lichten-

stein).

* An asterisk indicates that the species is extinct or no longer found
in this region.

Rancho La Brea.—The Rancho La Brea beds constitute one
of the most unique and at the same time one of the richest of
Pleistocene deposits in the west; unique because in the entomb-
ment of remains the factor of chance has been reduced to a
minimum by the presence of an attractively baited and auto-
matic trap; rich because the trap was insatiable in its demands,
because the material was promptly immersed and preserved in
semi-fluid asphalt, and because of the fact that the trap was
almost continually operative, it would seem, for a considerable
period of time.

According to Merriam,’ who bases his conclusions on per-
sonal observation and upon the opinions of Arnold, Orcutt, and
other geologists, crude asphaltic oil from the underlying Fer-
nando shales, here gently upfolded, has been forced to the sur-
face through cracks or chimneys in these folded strata to ac-
cumulate upon the surface as more or less extensive oil pools.
This heavy oil, under the influence of sun and wind, underwent
a process of natural distillation, becoming more and more viscid
until in the larger accumulations it was sufficiently tenacious
to entrap and hold the largest mammals of the region, Elephas,
Mastodon, and Paramylodon. As pointed out by the same
author, additions to these lenses of asphalt took place at the
center as fresh oil rose through the chimneys from below; at
the same time dust and sand drifted over and obscured the
firmer asphalt of the margins. These two factors combined to
bring about a most deceptive condition in the mass by leaving
the periphery fairly firm and yet permitting a gradually increas-

11 Merriam, J. C., Mem. Univ. Calif., vol. 1, No. 2, pp. 199-213, 1911.

76 University of California Publications in Geology [Vou.7

ing degree of plasticity toward the center without a positive de-
mareation of the danger zone. Upon this treacherous surface
a mammal would be unaware of danger until the dust-covered
surface yielded under his weight. His sudden start or his leap
for safety would make all the more complete his entanglement.

While these exposed traps must have been in many cases pas-
sive, concealed in an open or perhaps but slightly wooded
locality where animals would blunder into them, they must often
also have been actively attractive to animals through the two
important factors of water and food. During a considerable
period of time spent in working these fascinating deposits, the
author has had frequent recourse to the water accumulated in
depressions of the asphalt. This water has proven quite accept-
able for drinking and for bathing. As algae accumulate, frogs,
toads, dragonflies, mosquitoes, and other insect forms invade
it; rushes and marsh-grass border the pools, their roots actually
in contact with asphalt of the highest degree of tenacity. In
a number of cases the asphalt accumulations represent depres-
sions in the general surface of the country where not only the
direct rainfall would be temporarily held empounded but more
lasting pools representing surface drainage or even seepage
would accumulate. The presence of bedded leaf-masses and of
water-worn fragments of wood intermingled with the animal
remains would support the view that there were at times ponds
of a more or less permanent nature. The animals of poorly
watered regions in the southwest are perforce far from fas-
tidious in the matter of drinking water; hence the herbivorous
mammal must certainly have found the vicinity of these water
pools one offering very positive attraction as to water and
perhaps grass as well.

The entanglement of one ungulate would suffice to attract
a multitude of carnivores. The creature probably acted not
infrequently as live bait for a considerable time, so that its
struggles and outecries served to whet the appetites and overcome
the instincts of caution in the hungry carnivore. It appears
from Merriam’s studies that young animals or else old or dis-
eased individuals have very frequently been thus tempted,
though there appear animals of all ages.

1912] Miller: Pacific Coast Avian Palaeontology fer

The prevailing .eonditions also led to a greatly distorted
relation between OM cons and non-predaceous species in point
of numbers. While removing a single femur of Paramylodon
there were found touching it three complete skulls of Canis
indianensis, and even this proportion of three to one is much
too small to represent the facts truthfully. In a collection of
bird remains made by the writer the number of specimens of
Aquila exceeds the number representing all the non-raptorial
species combined, while fifty-six per cent of the species recorded
are predatory.

The cessation of struggling on the part of the entrapped
animal did not end its services as trap bait. Some forms which
normally seek an active prey, e.g., Canis and Aquila, may on
occasion resort to carrion. A decrepit wolf or a hungry eagle
may not infreqently thus supply the demands of necessity. The
odors emanating from these pits where freshly excavated are,
to human nostrils, strongly suggestive of carrion. Gases exhaled
by animal bodies submerged in the plastic mass would accen-
tuate this olfactory effect to such a degree as probably to attract
carrion feeders. Was this influence also felt by birds? Dar-
win’s well-known experiments on Andean condors kept in cap-
tivity have long been accepted as proving that the vultures do
not employ the olfactory sense in the perception of food. How-
ever, the experiences of later naturalists with Cathartes, which
is often caught in wolf-traps with concealed bait, leads us to
emphasize the fact that Darwin was experimenting with birds in
captivity which had been fed perhaps from early youth in more
or less regular fashion. We must at least concede it possible
that the abundant vulture remains in the asphalt are the result
in part of this factor of odor in attracting them to the locality.

78 University of California Publications in Geology [Vou.7

PartTiaAL List or MAMMALS

*Canis indianensis Leidy.

*Canis oreutti Merriam, J. C.

*Canis andersoni Merriam, J. C.

*Canis occidentalis furlongi Mer-
riam, J. C.

*Lynx occidentalis fischeri Mer-
neni Als (Cp

*Felis atrox bebbi Merriam, J. C.

*Smilodon californicus Bovard.

Mephitis, sp.

FROM RANCHO LA BREA.

Putorius, sp.

*Aretotherium californicum Mer-
riam, J.C.

*Hlephas, sp.

*Mastodon, sp.

*Equus, sp.

*Bison antiquus Leidy.

*Capromeryx minor Taylor.

*Camelops (?), sp.

*Paramylodon, sp.

SPECIES OF BirpS KNOWN FROM RaNcHO LA BREA.

Chaulelasmus streperus (Lin-
naeus).

Anser albifrons (Seopoli) ?

Branta canadensis (Linnaeus).

*Ciconia maltha Miller.

Jabiru myeteria (Lichtenstein).

Mycteria americana Linnaeus.

Ardea herodias Linnaeus.

*Grus minor Miller.

Grus canadensis (Linnaeus).

Lophortyx sp.

*Meleagris ?

*Pavo ecalifornicus Miller.

Gymnogyps californianus (Shaw).

*Sarcorhamphus elarki Miller.
*Pleistogyps rex Miller.
*Cathartornis gracilis Miller.
Cathartes aura (Linnaeus).
*Catharista occidentalis Miller.
*Teratornis merriami Miller.
Elanus leucurus (Vieillot).
Cireus hudsonius (Linnaeus).
*Cireus, sp.

Buteo, sp.

Buteo borealis (Gmelin).
Aquila chrysaétos (Linnaeus).

Hahaétus leucocephalus (Lin-
naeus).

*Morphnus woodwardi Miller.

*Geranoaétus grinnelli Miller.

*Geranoaétus fragilis Miller.

Faleo peregrinus Tunstall.

Faleo, sp.

Faleo sparverius Linnaeus.

*Polyborus tharus Auct.

Aluco pratincola (Bonaparte).

Asio flammeus (Pontoppidan).

Otus asio (Linnaeus).

Bubo virginianus (Gmelin).

Speotyto cunicularia hypogaea
(Bonaparte).

*Neomorpha, ? sp.

Colaptes cafer (Gmelin).

Otocoris alpestris (Linnaeus).

Corvus corax Linnaeus.

Corvus brachyrhynchos Brehm.

*Corvus, sp.

Xanthocephalus xanthocephalus
(Bonaparte).

Agelaius gubernator (Wagler).

Sturnella neglecta Audubon.

Pipilo, sp.

Lanius Inudovicianus Linnaeus,

* Specics marked with an asterisk (*) are extinct or foreign to the

loeality.

Fossil Lake.—The horizon designated by Cope as Silver Lake
and classed collectively with several other horizons as the Equus
Beds, was thought for many years to be of Pliocene age and
as such was considered by Cope and by Shufeldt in their studies

fewer oe

1912] Miller: Pacific Coast Avian Palaeontology 79

of the birds from that region. Our knowledge of the various
western horizons has, however, been extended by later investiga-
tors in stratigraphy and in the correlation of faunas, with the
result that these beds are now proven unquestionably to be of
Pleistocene age. Such change of interpretation alters materially
the significance of discoveries announced by Cope and by Shu-
feldt in that it reduces appreciably the extent to which several
existing genera are known to run back in time.

The various descriptions of this region are summarized in a
concise and very lucid paragraph or two by Osborn’? from which
the following may well be quoted:

“One hundred and fifty miles northwest of the old Lahontan shore
lines in the heart of the Oregon Desert of the great basin, and twenty
miles northeast of Silver Lake, there is a slight depression in the desert
perhaps twenty acres in extent marked Christmas Lake on the maps, to
which Cope gave the name ‘Fossil Lake.’ This ‘Silver,’ ‘Christmas,’ or
‘Fossil’ lake region was successively explored by Condon, Cope, Sternberg
(who made the chief collections), and Russel (1882)... . Though actually
twenty miles distant from Silver Lake, the rich fauna of mammals and
birds found has been deseribed by Cope13 and Shufeldt, and referred to by
Gilbert, as the fauna of the Silver Lake Equus beds... .

““Proof that the country was partly fluviatile and partly wooded is
afforded by the presence of the muskrat (Fiber), the otter (Lutra), the
beaver ( Castor fiber), and the giant beaver (Castoroides).

ce |... The bird life was very abundant and not very dissimilar from
what we might observe at any of the alkaline lakes of the West, resorted
to at the present day by wild fowl during their migrations. Great flocks
of swans (Cygnus paloregonus), geese (Anser condoni), and ducks were
there; a cormorant (Phalacrocorax) was among the rarities; among the
species of grebe (Podiceps occidentalis) is one still inhabiting this region.
There were also coots (Fulica minor) and herons (Ardea paloccidentalis).
Other forms of birds include two species of grouse, crows, and eagles. The
strangest figure upon the scenes among the birds was a true flamingo
(Phoenicopterus copei). The northernmost distribution of flamingoes at
the present is southern Florida and the Bahama Islands (lat. 27° N).
Shufeldt concludes that the climate might well be compared with that of
Florida or the lower part of Louisiana, that the vegetation was fully as
luxuriant as it now is in those parts, and that the palms were abundantly
represented. This conclusion as to a Floridan climate and the existence
of palms is, however, very questionable. Brown!4 observes that the South
American flamingoes (Phoenicopterus chilensis) migrate as far south as

12 Osborn, H. F., The Age of Mammals, p. 458.

13 Cope, E. D., The Silver Lake of Oregon and its Region, Am. Nat., vol.
3, pp. 970-982, 1889.
14 Mr. Barnum Brown in a note to the author [Osborn].

80 University of California Publications in Geology [Vou.7

the lakes in central eastern Tierra del Fuego, lat. 53° S, where they are
said to breed, and certainly spend a part of the season. This region cor-
responds in temperature to the climate of central Alberta, Canada, 400
miles north of Silver Lake. Thus it appears that the presence of Phoenicop-
terus copei at Silver Lake has very little weight in the determination of
climate. It is more probable that the northern lakes of that period con-
tained mollusks on which the flamingoes fed.’’

Aside from an extinct genus of grouse, Phoenicopterus is the
only genus recorded fossil that might not reasonably be expected
to occur in the region at the present time.

Shufeldt’s original paper’ gives a detailed description of
most of the species of birds found in the Fossil Lake beds and
a synoptical list of the known species was published in a paper
by the writer’® as follows:

AXchmophorus occidentalis (Lawrence).

Pygopodes: Echmophorus oecidentalis (Lawrence).
Colymbus holboelli (Reinhardt).
Colymbus auritus Linneus.
Colymbus nigricollis californicus (Fleermann).
Podilymbus podiceps (Linneus).
Lougipennes : Larus argentatus Pontoppidan.
Larus robustus Shufeldt.
Larus californicus Lawrence.
Larus oregonus Shufeldt.
Larus philadelphia (Ord).
Xema sabini (J. Sabine).
Sterna elegans Gambel.
Sterna forsteri Nuttall.
Hydrochelidon nigra surinamensis (Gmelin).

Steganopodes: Phalacrocorax macropus (Cope).
Pelecanus erythrorhynchos Gmelin.
Anseres: Lophodytes cucullatus (Linnaeus).

Anas platyrhynchos Linnaeus.
Mareca americana (Gmelin).
Nettion carolinense (Gmelin).
Querquedula discors: (Linnaeus).
Querquedula cyanoptera (Vieillot).
Spatula clypeata (Linnaeus).
Dafila acuta (Linnaeus).

Aix sponsa (Linnaeus).

15 Shufeldt, R. W., Journ. Acad. Nat. Sci. Phila., ser. 2, no. 9, pp. 389-

45, 1892.
16 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geok, vol. 6, pp. 79-87,

1912] Miller: Pacific Coast Avian Palaeontology 81

Marila valisineria (Wilson).
Clangula islandica (Gmelin).
Harelda hyemalis (Linnaeus).
Anser condoni Shufeldt.

Anser albifrons gambeli Hartlaub.
Branta hypsibata Cope.

Branta canadensis (Linnaeus).
Branta propinqua Shufeldt.

Chen hyperboreus (Pallas).

Olor paloregonus (Cope).

Odontoglossae : Phoenicopterus copei Shufeldt.
Herodiones : Ardea paloccidentalis Shufeldt.
Paludicolae: Fulica americana Gmelin.

Fulica minor Shufeldt.
Limicolae: Lobipes lobatus (Linnaeus).
Gallinae: Tympanuchus pallidicinetus (Ridgway).

Pedioecetes phasianellus columbianus (Ord).
Pedioecetes lucasi Shufeldt.
Pedioecetes nanus Shufeldt.
Palaeotetrix gilli Shufeldt.

Accipitres: Aquila pliogryps Shufeldt.
Aquila sodalis Shufeldt.

Striges: Bubo virginianus (Gmelin).

Passeres: Euphagus affinis Shufeldt.

Corvus annectens Shufeldt.

ADDITIONAL SPECIES OF BIRDS IN THE CALIFORNIA COLLECTIONS

Pygopodes: étichmophorus lucasi Miller.
Anseres: Erismatura jamaicensis (Gmelin).
Accipitres: Cireus hudsonius (Linnaeus).

PartTiaAL List oF MAMMALS FROM FossIL LAKE.!7

Ursus, sp. Lepus, sp.

Felis, sp. Mylodon sodalis Cope.
Canis latrans Say. Equus pacificus Leidy.
Canis, ef. occidentalis Richardson. Equus, n. sp.

Vulpes, ef. pennsylvanicus Bodd. Elephas, sp.

Lutra canadensis Schreber. Platygonus, cf. vetus Leidy.
Fiber zibethicus Linnaeus. Platygonus, sp.

Arvicola, sp. Eschatius conidens Cope.
Thomomys, sp. Camelops kansanus Leidy.
Geomys, sp. Camelops vitakerianus Cope.
Castor, sp. Camelops, sp.

Castoroides, sp. Antilocapra, sp.

17 Sinclair, W. J., Univ. Calif. Publ. Am. Arch. Ethn., vol. 2, p. 1, 1904.

82 University of California Publications in Geology [Vou.7

Rodeo Pleistocene—Almost. nothing has been recorded con-
cerning this formation. The region has been repeatedly visited
‘by parties from the University of California and the Pleistocene
age of the beds definitely established.

The single specimen of bird remains from the locality was
picked up at the base of the exposure by Professor J. C. Mer-
riam with parts of the matrix of the Pleistocene beds still adher-
ing to it. The bone is a perfect tarsometarsus of average size.

SINGLE SPECIES FROM RODEO PLEISTOCENE.

AKchmophorus occidentalis (Lawrence).

PRESENT PHYSIOGRAPHIC AND GEOGRAPHIC RELATIONS OF THE
West AMERICAN REGIONS IN WHICH Fossiu AVIAN
REMAINS ARE KNOWN

The nine localities referred to above have yielded several
thousand specimens in all. Only five of these specimens, repre-
senting three species, are from deposits older than the Pleisto-
cene ; hence we may consider our knowledge as practically limited
to that age. Since also the systematic groups larger than the
species display in the case of birds such remarkable longevity,
time relations between the several Pleistocene horizons become
of minor importance except as we learn of variations in climate
during that period.

There is on the other hand an advantage to be derived from
the approximate contemporaneity of the deposits. The entomb-
ment of many specimens at about the same time under a variety
of conditions and in a number of different localities gives us
an unusually accurate conception of the avifauna of that time.
The Fossil Lake deposits yield mainly those species to be found
about open, shallow lakes; the caverns are so located as to have
entombed those species which inhabit lower mountainous coun-
try ; the Rodeo Pleistocene consists of seashore accumulation; the
Rancho La Brea beds are the result of a peculiarly diverse com-
bination of circumstances which led to the trapping of open-
plains birds with a preponderance of raptorial species.

The asphalt beds lie in latitude 34° N, on the coastal side of
the Santa Monica Mountains within a few miles of the sea and

~ oe

1912] Miller: Pacific Coast Avian Palacontology 83

less than two hundred feet above its level. The locality is today
a typical open valley country, protected on the north by the
east-and-west Santa Monica Range, yet tempered by the cool
and moisture-laden breeze from the sea. Faunally, the locality
lies in the Upper Sonoran zone of the San Diego region.

The Shasta caves occupy a position further inland and seven
degrees to the northward of Rancho La Brea. Their elevations
vary between 1300 and 1500 feet above sea-level. The isothermic
zone represented is slightly above that of Rancho La Brea, it
being Upper Sonoran and lower Transition. The isohumic area
is that of the Sacramento-San Joaquin, which is an area of
slightly greater precipitation than is the San Diegan.

The two localities are at present distinguishable in their avi-
fauna by the presence or the absence of several species which
are of interest in the light of palaeontological records. The
entire group of grouse, represented in the Shasta region by
Dendragapus, is wanting at Rancho La Brea. Oreortyx and
Cyanocitta, present in the cave region, are wanting in the im-
mediate vicinity of the asphalt beds. Geococcyx, present in the
latter locality, is wanting in the former.

These, however, are birds of slight volant power. The species
of less restricted activity, such as the Raptores and the water-
birds, are common to the two localities at present.

The Fossil Lake region of Oregon lies in latitude 43° N, full
nine degrees north of Rancho La Brea, and is on the eastern
side of the Cascade Range. This separation from the coastal
slope would influence the smaller species of birds more than the
larger. Winter temperatures would be more severe, with sum-
mer temperatures fully equal to those of southern California.
The rainfall at the present time is such as to give the region
the name of ‘‘Oregon Desert.”’

There appears, then, as distinguishing the five more import-
ant localities today, a difference of nine degrees of latitude, a
range of elevation from 100 to 1500 feet above the sea, and a
faunal difference limited to the Upper Sonoran and lower
Transition zones. There is no evidence of marked change in
elevation since Pleistecene times; hence it seems probable that
a somewhat similar relationship between the localities prevailed

84 University of California Publications in Geology (Vou.7

during the Pleistocene period and that the specimens obtained
from the various horizons represent in the aggregate, with a
considerable degree of accuracy, the avifauna of the Pacific
coast at that time.

RELATION OF PLEISTOCENE FAUNAS TO THOSE OF THE PRESENT
Day

A partial list of the Recent birds of the Transition zone in
the Shasta region is given in the report of a biological survey
of the region by C. H. Merriam.'® The list is appended here
and the more striking differences displayed by the other loeali-
ties are noted. This comparison may prove of interest in con-
sidering the fossil avifauna.

RECENT AVIFAUNA OF THE SHASTA REGION

(Partial list from Upper Sonoran and Transition zones)

Oreortyx picta (Douglas).
Lophortyx californica (Shaw).
Dendragapus obscurus (Say).
Zenaidura macroura (Linnaeus).
Cathartes aura (Linnaeus).
Cireus hudsonius (Linnaeus).
Buteo borealis (Gmelin).
Aquila chrysaétos (Linnaeus).
Faleo mexicanus Schlegel.
Ialeo sparverius Linnaeus.
Bubo virginianus (Gmelin).

Speotyto cunieularia (Molina).
Glaucidium gnoma Wagler.
Colaptes eafer (Gmelin).
Aphelocoma californica (Vigors).
Cyanocitta stelleri (Gmelin).
Sturnella neglecta Audubon.
Euphagus cyanocephalus (Wagler).
Lanius ludovicianus Linnaeus.
Planesticus migratorius (Lin-
naeus).

To this list may be added the following species which possibly
occur in the locality, though not recorded by the collectors of

the survey party:

Accipiter velox (Wilson).

Accipiter cooperi (Bonaparte).

Astur atricapillus (Wilson).

Buteo swainsoni Bonaparte.

Archibuteo ferrugineus (Lichten-
stein).

Haliaétus leucocephalus (Lin-
naeus).

Gymnogyps californianus (Shaw).

Faleo peregrinus Tunstall.

Alueo pratincola (Bonaparte).
Asio wilsonianus (Lesson).

Otus asio (Linnaeus) .
Geococcyx ecalifornianus (Lesson).
Corvus corax Linnaeus.

Corvus brachyrhynchos Brehm.
Cosmopolitan water birds

18 Merriam, CU. H., Results of a Biological Survey of Mt. Shasta, Cali-

fornia, N. Am. Fauna, No. 16, 1899.

1912] Miller: Pacific Coast Avian Palaeontology 85

Some REcENT Birps NOTED IN THE SILverR LAKE REGION.19

Geese, Swans, Pelicans, Cormorants Oreoscoptes montanus (Townsend,
4Echmorphorus occidentalis (Law- J. K.)

rence). Asyndesmus lewisi Riley.
Myadestes townsendi (Audubon). Recurvirostra americana Gmelin.
Ixoreus naevius (Gmelin). Himantopus mexicanus (Miller).

If, as is suggested by the configuration of the country, the
former elevation of the caves was slightly less than at present
and the country less broken, conditions were then more favor-
able than at present for such species as Geococcyx californianus
and Archibuteo ferrugineus. The probability that slow-moving
streams and small lakelets served to attract waders, anserines,
and Haliaétus would be greater in such a condition of the eoun-
try.

In the vicinity of Fossil Lake, Oregon, the present avifauna
would show probably several points of divergence from the cave
region and from Rancho La Brea. Orecortyr, Cyanocitta, Aphe-
locoma, and Geococcyx would probably be lacking, while one
would doubtless meet with Pedioecetes, Centrocercus and Cyano-
cephalus.

At Rancho La Brea, Elanus and Geococcyx would prove more
abundant, Agelaius, Nanthocephalus, and Otocoris would be
plentiful, while Dendragapus, Oreortyx, and Cyanocitta would
not be likely to occur. Elanus and Geococcyx at Rancho La
Brea, Dendragapus in the Shasta region and Centrocercus and
Pedioecetes in the Fossil Lake region are the chief differences
dependent upon latitude to be noticed among the three faunas.
The other discrepancies are such as would be due to slight differ-
erence in altitude, the proximity of water or the topography of
the region.

The long list of smaller passerines, piciforms and machro-
cheirs is here purposely omitted, since they, though very im-
portant in the determination of faunal zones, seem not to have
been preserved in the fossil state to any great extent.

Distribution of the Cathartidae—One of the groups of chief
interest in discussing the subject of distribution in the lght

19 Cope, E. D., The Silver Lake of Oregon and its Region, Am. Nat., vol.
23, p. 970, 1889.

86 University of California Publications in Geology (V0.7

of palaeontological study is the raptorial subdivision embracing
the New World vultures. The exclusive possession by the
Americas of so marked a group of large and strong-flying birds
as the Cathartidae and the total absence there of any form of
the true Vulturidae, which occupy the same bionomic position
in the Old World, is one of the striking phenomena in animal
distribution. Aside from the fact that the group is so well
defined, there being no Recent forms showing transition between
it and the other raptorine subdivisions, we find it not poor in
species and it is widely distributed in the western hemisphere.

There are endemic to the New World no less than five distinet
cathartine genera—a goodly number for a group, the smallest
member of which approaches in size the largest eagles. All are
birds capable of long-sustained flights and they are unsurpassed
in their ability to meet the emergencies of changed elevation
and shifting air currents that would prove disturbing to less
perfect fliers. This very factor may, by insuring them against
being driven astray by storms, bring about a distribution more
in accord with their own needs or inclinations.

As an instructive comparison in the matter of distribution
one might consider the short-eared owl (Asio flammeus). This
bird is almost cosmopolitan, occurring unmodified over both
hemispheres and even in such isolated islands as the Hawaiian
group, though no more maritime and no more eapable a flier
than the cathartid vultures. It might be suggested as a dis-
tinction between these two cases that the vultures are non-
migratory and are confined to the tropics, and would, therefore,
have no tendency to wander, would not be exposed to the danger
of scattering by storms and would always be separated from the
other continents by the widest parts of the ocean basins. An
examination of the ranges and the habits of the existing species
will, however, prove the fallacy of such views. Cathartes awra
is migratory or not as occasion demands. It is resident to 40° N
latitude and thence northward it becomes migratory, being
starved out in winter. Its habitual range extends from 55° N
latitude to Tierra del Fuego and the Falkland Islands on the
south.?°

20 Coues, E., Key to N. Am. Birds (ed. 5; 1903), vol. 2.

1912] Miller: Pacific Coast Avian Palaeontology 87

Other members of the group range as follows: The Andean
eondor (Sarcorhamphus) oceurs along the Cordillera from
equatorial Peru to the extremity of Patagonia and from sea-
level to the highest summits of the Andes; Catharista urubu
inhabits the whole of tropical America, southward to Argentina
and northward as a straggler to the Canadian border; the two
remaining genera, Gyparchus and Gymnogyps, occupy suecces-
sively more circumscribed areas. Not, however, till the latter
was so nearly exterminated by human agency, was either form
of restricted range. Gymnogyps is confined entirely to the
Nearctic realm, Sarcorhamphus is entirely Neogaeic, but the three
remaining forms are distributed without regard to realm and
all are independent of the generally recognized life-zones. That
a group thus distributed, many of whose members are so in-
dependent of climatie and of minor geographic barriers, should
be hmited to the western hemisphere seems indeed strange.

The influence of a virile and aggressive species is not infre-
quently effective as a barrier to the distribution of a less active
one and it may be urged that the slightly more rapacious vul-
turines of the Old World have served as a check upon any ten-
dency of the cathartids to diffuse into Eurasia. Such a view is
controverted by the fact that the latter birds prove themselves
perfectly able to maintain their existence in competition with
the polyborine scavengers which, in a way, represent the Old
World vultures in their habits.

With the geographical limitations of the group before us, the
question of ancestry and the geological record assume a very
important aspect.

Concerning the antiquity of the group there is unfortunately
but little known. Previous to the opening up of the Rancho La
Brea deposits in California, fossil cathartids of unquestionable
identity were unknown to North America. Cope’s Palaeoborus
umbrosus** from the Pliocene of New Mexico, which he orig-
inally placed in the genus Cathartes, he later transfers to the
genus Vultur. The new genus Palaeoborus was established by
... . the description and figures

Coues for its reception since

21 Cope, E. D., U. S. G. Surv. W. of 100th Merid., vol. 4, pt. 2, p. 287,
1876.

88 University of California Publications in Geology (Vou. 7

clearly indicate a bird generically distinct from Cathartes and the
improbability of the occurrence of a true Vultur in North

America is extreme.’’*? With the former point at least there can
be no possible disagreement after a consideration of Cope’s figures
of Palaeoborus. Whether the form may be considered cathartine
at all is open to very serious question. Lueas?* considers it as
more probably of polvborine affinities.

In South America fossil cathartids are less rare. Cathartes
and Gyparchus are reported from the Pleistocene caves of
Brazil.** Moreno and Mercerat?* describe two species from the
Pampean Pleistocene and three from the Pliocene of the Santa
Cruz. The Pleistocene species, Cathartes fossilis and Sarco-
rhamphus fossilis, represent genera still existing in that region.
The three species from the Santa Cruz, Psilopterus communis,
P. australis and P. intermedius, belong to an extinet genus which
is placed by the authors adjacent to Cathartes and is considered
by them to be intermediate or transitional between that genus
and Sarcorhamphus. The three species of Psilopterus are based
on the most fragmentary material. The figures are such as to
indicate specimens in rather poor state of preservation as to sur-
face markings. Trochleae are corroded away and intermuscular
lines are entirely wanting. P. intermedius is based on a single
specimen consisting of two tarsal trochleae. The other two
species are based upon fragmentary tarsi poorly preserved.
While there may be no question in the minds of these authors
as to the relationships of the genus Psilopterus, there appears
nothing in the lithographed figures or in the very meager descrip-
tions that is at all convincing.

Beyond the above instances, the only record of fossil cath-
artids previous to the excavations at Rancho La Brea is the
remarkable specimen made known by Gaillard?* from the phos-
phorites of Querey, an Oligocene horizon in France. This species,

22 Coues, E., Key to N. Am. Birds (ed. 2; 2884), p. 822.

23 Lueas, F. A., in Zittel’s Text-Book of Palaeontology, Eng. trans., vol.
2, p. 277, 1902.

24 Winge, O., Fugle fra Knoglehaler i Brazilien, Museo Lundii, 1887.

25 Palae. Argentina, An. Mus. La Plata, pt. 1, p. 67, 1891.

26 Gaillard, C., Ann. de 1’Univ. de Lyon, n. ser. 1, Se. & Med., fase. 23,
1908.

1912] Miller: Pacific Coast Avian Palaeontology 89

Plesiocarthartes europeus Gaillard, thus becomes at once the
most ancient cathartid, and the only instance known to the
author of the occurrence, fossil or Recent, of the family outside
the American continents. The species, as far as ean be learned,
is represented by a single bone, a fragmentary tarsometatarsus
preserved in the Museum of Lyons. The specimen is, however,
sufficient to establish beyond question the cathartine relation-
ships of the species. Its author considers the case to be one of
an individual’s having straggled from its normal range. In
view of the extensive examination of most of the European
horizons which has failed thus far to furnish evidence of its
further occurrence there, the conclusions reached by Dr. Gail-
lard may be considered as probably correct.

With the progress of work at the University of California
our knowledge of the group under discussion is considerably
advanced. In the collections from Fossil Lake the abundant
avian remains are almost entirely of aquatic forms, although
there appear in the University collections, as well as in the much
larger Cope and the Condon collections, a number of raptorial
species. There are, however, no specimens referable to the Cath-
artidae, a rather conspicuous absence.

There appears no reason deducible from the habits of the
turkey vulture of today why, if vultures were present during
the formation of these beds, their remains should not have been
preserved there. In fact, there is every reason for considering
the vulture a more favorable subject for preservation in such
deposits than are the other raptors. The turkey vulture is one
of the commonest of beach-combers along the shores of both fresh
and salt-water bodies and it comes habitually in great flocks to
spend the warmer parts of the day wading in the shallower
waters or sitting about the sand bars of quiet streams. The
negative evidence very strongly suggests the absence of cath-
artids from the region during the deposition of the Fossil Lake
beds.

Potter Creek and Samwel caves both furnish remains of
these vultures, while the Rancho La Brea asphalt is especially
rich in raptorial species, about equally divided between the eath-
artids and the falconids.

90 University of California Publications in Geology (Vou. 7

At Rancho La Brea there oceur six truly cathartine species
as follows: Gymnogyps californianus, Sarcorhamphus clarki,
Cathartornis gracilis, Pleistogyps rex, Cathartes aura, and Cath-
arista occidentalis. Besides these forms, the aberrant Teratornis
is nearer to the Cathartidae than to any other family at present
recognized. In the cave deposits there appear the two forms,
Catharista shastensis and Gymnogyps amplus, belonging to ex-
isting genera.

The condors and Teratornis represent the extreme of spe-
cialization in point of size, the greatest degree of diversity, and
possibly also the least specific longevity. Gymnogyps californi-
anus alone of the six larger forms has persisted unchanged from
the time of formation of the asphalt beds, where it is the most
abundant of the condors, until the present time, when it seems
on the verge of extinction. Probably its associates of that time
had passed the prime of their specifie existence while the present
form, less specialized toward gigantism, constituted a younger
development reaching its maximum of virility later than its
congeners but becoming decadent by the present time.

As a result of the excavations at Rancho La Brea the genus
Catharista became known to the Pleistocene of North America,
its first discovery in the fossil state. Its range was at the same
time extended from its previous limits—the tropical and lower
Austral zones of both continents—to include the Pacific Coast
region of California, an area at present occupied by an Upper
Sonoran fauna. The fossil species C. occidentalis is found in
ereat abundance in the asphalt. Its relative abundance as com-
pared with the other vultures there is shown by a census of an
unassorted collection of the bird remains, which gave the fol-
lowing results:

Gymnogyps californianus 11 individuals
Cathartes GUNG -..c22-.--.-2ee 20 individuals
Catharista occidentalis ..........------------------ 21 individuals

As indicated in the note descriptive of Catharista occidentalis,
the difference between the fossil and the Recent forms lies in the
ereater body size of the fossil form accompanied by a difference
in proportion of the segments of the posterior limb. The tarsus
Polyborus there appear the following fossil forms whose nearest

1912] Miller: Pacific Coast Avian Palaeontology 91

shows a greater degree of robustness, both absolute and relative.
The humerus.is slightly longer and stouter, but whether the wing
expanse is increased to a degree commensurate with the in-
creased body weight is questionable. We seem, then, to be deal-
ing with a vulture that was of a heavier body and _ shorter
limb than the persistent Catharista urubu. The difference be-
comes more significant when it is noted that the character separ-
ating the extinct from the persistent species of Catharista is
identical with one of those separating the more restricted Cathar-
ista urubu from the wider ranging Cathartes aura. It should
also be noted that the extinet form Catharista shastensis from
the caves is separable from the Rancho La Brea species, C. occi-
dentalis, by a greater robustness of the tarsometatarsus and
by a greater body size as indicated by its stouter coracoid. The
cave form, the asphalt form, and the Recent form of Catharista
thus fall with the Recent Cathartes into a series of progressively
lighter-bodied and possibly more strongly flying vultures, which
display, in the cases of the last three at least, a progressively
ereater ability to cope with their environment.

That the cavern and the asphalt deposits are not of the same
age is evidenced by the occurrence therein of distinct but closely
related species of cathartids belonging to two genera, i.e. Gym-
nogyps and Catharista. The localities are separated by approx-
imately seven degrees of latitude and a difference in elevation
of fourteen hundred feet. Both lie at present in approximately
the same faunal zone. Species possessed of the excellent volant
powers shown by the large vultures when present in the con-
siderable numbers indicated by their remains in the two deposits
would searecely feel the restrictions of such slight barriers as
could have existed at that time.

The existing species of Gymnogyps, before its numbers were
depleted by the influence of man, ranged from Lower California
to British Columbia and from sea-level to the summits of the
Coast Range, while the existing Cathartes is almost ubiquitous.
Furthermore our knowledge of the Recent vultures as a group
would lead us to discard as incongruous the conception of a
vulture so strictly boreal as to come southward in considerable
numbers as far as the Shasta region and not reach the more

92 University of California Publications in Geology (Vou. 7

favorable environment of Southern California. We must, then,
almost of necessity conclude that the separation of the two faunas
is due to difference in time rather than to any other factor.

The two horizons have in common with the Recent North
American fauna three cathartine genera, viz., Cathartes, Cath-
arista, and Gymnogyps. Catharista, at present foreign to the
immediate vicinity, is represented in the two deposits by distinct
species. Gymnogyps californianus is abundant in the asphalt
beds and in the Recent fauna of a region including and extend-
ing far beyond both localities, yet the genus is represented in
the cave deposits only by a distinct species, G. amplus. It is
hard to explain how the cavern deposits could have been inter-
polated between the Rancho La Brea horizon and the Recent
and still possess two distinctive cathartine forms and only one,
Cathartes aura, in common with either of them.

Distribution of Falconidae.—Palaeontology has added mate-
rially to our knowledge of this group in at least two respects,
namely in our concepts of the former distribution of its members
and of the degree of adaptive radiation that has taken place
within its limits. The three genera Geranoaétus, Morphnus, and
Polyborus, limited in Recent time to tropical or to south tem-
perate America, are now known to have ranged in the previous
period well up into California. Geranoaétus went as far north
as Hawver Cave and the other two as far as Los Angeles. The
larger phase of Haliaétus, which is lhmited at present to the
northern parts of North America, had not at the time of deposi-
tion of the asphalt beds withdrawn to the northward as a
distinct geographical race. The remains of Haliaétus lewcoce-
phalus from these beds embrace in their range of variation ex-
tremes of size surpassing at either end of the scale the two
existing races, H. 1. alascanus and H. l. leucocephalus now geo-
graphically distinct.

As illustrative of the number of adaptive radiations of the
eagle group we may point to the six fossil eagles of Marsh,
Shufeldt, and Miller. These are as follows: Aqwila sodalis, A.
pliogryps, A. dananus, Morphnus woodwardi, Geranoaétus grin-
nelli, and G. fragilis. Besides these extinct forms there were
found fossil the three persisting species Aquila chrysaétos,

1912] Miller: Pacific Coast Avian Palaeontology 93

Haliaétus leucocephalus, and Geranoaétus melanoleucus. Aquila
pliogryps Shufeldt is deseribed from a single bone, the basal
phalanx of the right hallux. The species is considered to be
slightly larger but more slender-limbed than Aquila chrysaétos.
The material representing the species is so limited that no clear
impression of its closer relationships can be formed. Morph-
nus woodwardi from Rancho La Brea may well have been such
a bird, though there is no way of obtaining more than the sug-
gestion of similarity from the fact that they were both eagles
of slender build. The statement made by Shufeldt is that Aquila
pliogryps was slender of foot, as indicated by the slightly longer
digits. Morphnus is a genus of long-shanked eagles with rela-
tively weak feet, as indicated by the size of the trochleae. The
digits certainly must have been much smaller in Morphnus wood-
wardi than in Aquila chrysaétos or in A. pliogryps.

Shufeldt’s species, A. sodalis, is founded on the proximal
part of a tarsometatarsus. The specimen is figured from the
anterior aspect drawn to natural seale. Compared with the
Rancho La Brea eagles, A. sedalis corresponds quite closely in
size with Geranoaétus fragilis, the smallest of the group there
represented. A. sodalis seems, however, to be of an entirely dif-
ferent nature if the position of the papilla of the tibialis anticus
may be taken as indicative. In a discussion of the splendid
series of eagle tarsi from the asphalt, it has been pointed out
by the author?’ that the position of this tubercle seemed to bear
a very definite relation to the slenderness of the tarsus, i.e., the
long-shanked forms have the tubercle placed high up on the
shaft of the bone. Applying this principle to Shufeldt’s figure
of A. sodalis, it would seem that the Fossil Lake species was
not of the same group of eagles as the more southern genera
Morphnus and Geranoaétus assembled by Ridgway under the
eaption Morphni. In A. sodalis the papilla of the tibialis anticus
is placed farther down the shaft and the proximal foramina are
separated by a much wider space. Unfortunately the charac-
ter of the hypotarsus is not shown in Shufeldt’s figure of Aquila
sodalis nor is an accurate impression of the region obtainable
from the description. It seems proper to consider the two species

27 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 305, 1911.

94 University of California Publications in Geology (VoL.7

deseribed by Shufeldt as distinct from any of the Rancho La
Brea forms.

Aquila dananus Marsh?® is described as being slightly smaller
than the existing A. chrysaétos. A single specimen of the species
was taken in the Loup Fork of Nebraska. It consists of the
distal part of the tibia only and is not figured by Marsh in the
original description. The assignment of the specimen to the
genus Aquila is proper in the absence of any feature to dis-
tinguish it from that genus. The suggestion of the possible
identity of one of the Fossil Lake forms, A. sodalis, with Marsh’s
A. dananus is made in Shufeldt’s paper but that author con-
siders the case improbable on the score of smaller dimensions in
the former species. Geranoaétus gracilis Miller from the asphalt
is the smallest of the fossil eagles from California and, as indi-
eated above, this species is about the same size as A. sodalis Shu-
feldt. Marsh himself considered the Loup Fork specimen to be
‘nearly as large as the Golden Eagle,’’ in which case A. dananus
may be considered as probably intermediate in size between
Aquila chrysaétos (Linnaeus) and Morphnus woodwardi Miller.

The only other fossil faleonids from American localities out-
side of California are Cope’s Palacoborus wmbrosus,?? which

Lueas'

2
30

very properly ascribes to the Polyborinae, and two species
from South America recorded by the Argentine palaeontologists,
Moreno and Mercerat.*t Lagopterus minutus Mor. and Mer. is
the smaller of these two South American species. It is repre-
sented by an almost perfect humerus which, according to the
authors describing it, is intermediate between Buteo and Poly-
borus, with the preponderance of characters relating it with
Polyborus. The other species, Foetopterus ambiguus, Mor. and
Mer., is considered to be intermediate between Buteo and Cath-
artes, but is assigned by the authors to the Falconidae. The

28 Marsh, O. C., Am. Journ. Scei., vol. 2, p. 125, Aug. 1871.

29 Cope, E. D., U. S. Geol. Surv. W. of 100th Merid., vol. 4, pt. 2, p. 287,
1876.

30 Zittel, Textbook of Palaeontology, trans. by Eastman, vol. 2, p. 277,
1902.

31 Moreno and Mercerat, Palae. Argentina, An. Mus. La Plata, vol. 1,
1891.

1912] Miller: Pacific Coast Avian Palaeontology 95

more intimate relationships of the forms are not discussed by
the authors.

List OF SPECIES ASSIGNED TO THE SUBORDER FALCONES THAT ARE KNOWN
To Occur AS Fossits In NortH AMERICA

Species marked with the asterisk are extinct or are no longer repre-
sented in the region. Species marked with the double asterisk are con-
sidered to show their closest relationship to forms at present more southern
in their distribution.

Elanus leucurus (Vieillot), Rancho La Brea.
Cireus hudsonius (Linnaeus), Rancho La Brea, Fossil Lake.
**Circus sp. (smaller than hudsonius), Rancho La Brea,
Aquila chrysaétos (Linnaeus), Rancho La Brea.
*Aquila sodalis Shufeldt, Fossil Lake.
*Aquila pliogryps Shufeldt, Fossil Lake.
*Aquila dananus Marsh, Loup Fork.
Haliaétus leucocephalus (Linnaeus), Rancho La Brea.
**Morphnus woodwardi Miller, Rancho La Brea.
**Geranoaétus grinnelli Miller, Rancho La Brea.
**Geranoaétus melanoleucus Auct. (?), Hawver Cave.
**Geranoaétus fragilis Miller, Rancho La Brea.
Buteo borealis (Gmelin), Rancho La Brea, Potter Creek Cave.
Buteo swainsoni (?) Bonaparte, Samwel Cave.
*Buteo, sp. (larger than Archibuteo), Rancho La Brea.
Archibuteo ferrugineus (Lichtenstein), Hawver Cave.
Faleo peregrinus Tunstall, Rancho La Brea, Potter Creek Cave.
*Faleo, sp. (smaller than peregrinus), Rancho La Brea.
Falco sparverius Linnaeus, Rancho La Brea, Samwel Cave and Potter
Creek Cave.
**Polyborus tharus Auct., Rancho La Brea,
*Palaeoborus umbrosus (Cope), Loup Fork of New Mexico.
Accipiter velox (Wilson), Samwel Cave.

The species of Circus remaining undetermined is a form
smaller than the North American C. hudsonius. It is not named
in this paper since no opportunity has been presented to com-
pare it with the South American species Circus cinereus and
C. maculosa. The last two species, it seems, are smaller than
C. hudsonius and possibly the asphalt specimens referred to the
indeterminate species are of a form identical with the one or
the other.

The material from Rancho La Brea representing Polyborus
is abundant and embraces most parts of the appendicular skele-
ton and the beak, including the characteristic nareal region.
All this material was compared very carefully with the Recent

96 University of California Publications in Geology (Vou. 7

phase of Polyborus tharus as represented by a single specimen
from Argentina. As no appreciable difference could be noted,
the fossil form is referred to the existing species, P. tharus.

Anomalies in Distribution—According to Ridgway? the
present distributien of Polyborus tharius is from Amazonia south-
ward through South America. The bird thus reaches in the
Argentine and the Patagonian climates a set of conditions as
rigorous as any that it would be liable to experience in the
northern hemisphere in the latitude of Los Angeles. The ex-
tremes of climate due to the presence of the ice sheet is thought
by Allen to have given rise to the periodical movements of birds
which finally merged into the present seasonal migration.**
Would not a plausible explanation be that the polyborine under
discussion was driven southward by the cold of the glacial epoch
but failed to respond to the later amelioration of climate because
of a nature less susceptible to the development of a migratory
instinct and therefore remained in the lower latitudes or’ below
the tropics? No record of the true Polyborinae is yet found
in the deposits of the southern hemisphere to correspond with
the Phocene form, Palaecoborus umbrosus (Cope), from New
Mexico or to extend the occurrence of the group even back to
the Pleistocene, as the Rancho La Brea material does so abund-
antly for the northern hemisphere. If, on this slender thread
of negative evidence, we assume that the group arose in the North
Temperate zone, the explanation suggested above seems a
plausible one.

Geranoaétus and Circus present eases similar to that of Poly-
borus, while Morphnus differs in that the genus is at present
limited to the tropics and probably never reaches a southward
distribution which would correspond climatically with the region
of Hawver Cave or of Los Angeles.

These two cases of Polyborus and Morphinus mentioned above
are typical of as many classes of change in distribution since
the formation of the various Pleistocene deposits. Parallel with
Polyborus there appear the following fossil forms whose nearest

32 Ridgway, R., U.S. Geol. & Geog. Surv. Terr., vol. 1, No. 6, p. 451, 1876.
33 Allen, J. A., The geography and distribution of birds, Auk. vol. 10,
No. 2, April, 1893.

1912] Miller: Pacific Coast Avian Palaeontology om

relatives occur in the southern hemisphere at a latitude corres-
ponding with the region of deposit in the northern hemisphere.

Fossil Species Nearest Living Relative
Phoenicopterus copei Shufeldt.............. Phoenicopterus ruber ? Linnaeus
iconia maltha Miller...............2..2..2.-2--- Euxenura maguari (Temm.)
Mycteria americana Linnaeus Mycteria americana Linnaeus
Jabiru mycteria (Lichtenstein) ............ Jabiru mycteria author
Catharista occidentalis Miller................ Catharista urubu (Vieillot)
Sarcorhamphus clarki Miller... Sarcorhamphus gryphus Auct.
Cin CUS SP ase ceases See tecees fester; aves ccervizcsaste Cireus cenereus or C. maculosus
Geranoaétus melanoleucus Auct............. Geranoaétus melanoleucus Auct.
Geranoaétus fragilis Miller
Polyborus tharus Auct...........................Polyborus tharus Auct.

Cases parallel with Morphnus in having their nearest related
Recent phase limited to more tropical zones are as follows:

Fossil Species Nearest Living Relative
Pavo californieus Miller... Pavo cristatus or Meleagris ocellatus
Morphnus woodwardi Millev.................. Morphnus guianensis Auct.
Geranoaétus grinnelli Miller Morphnus guianensis Auct.
Micropallas whitneyi (Cooper).............. Micropallas whitneyi (Cooper)

(GEOCOCC YR (U2) aSPs ceceece ee tee-ceeeeeeeve ces cess Neomorpha geoffroyi (Temm.)

One of the striking features in the study of so representative
a series of deposits, all of so nearly the same age as are the
bird-bearing deposits of the Pacifie Coast, is the total absence
of certain forms which one would expect to find therein. While
it is conceded that negative evidence in palaeontology is a frail
peg upon which to hang an opinion, yet the negation may be so
pronounced and so uniformly persistant that, in some cases at
least, the only conclusion possible is that species did not occur
in the region during the time of deposition.

The particularly favorable conditions offered at Rancho La
Brea for the trapping of vultures and eagles has been commented
upon in a previous paper on the condors. There was exposed
at that place during an indefinite period a more or less con-
stantly baited trap which was unusually attractive to both vul-
ture and eagle. It was automatic in its operation, effective in
its hold upon the victim, and almost ideal in the preservation of
its catch, the remains of which were sealed from the air in hquid
asphalt while still in the flesh. The entire collection of raptorial
remains includes, however, no specimen of the royal vulture
(Gyparchus papa) or of the harpy eagle (Thrasaétus harpya),

98 University of California Publications in Geology (Vou. 7

both of which occur at present along the Mexican border within
fifteen degrees of the latitude of Los Angeles.

The collection of wading birds from the coast, while not rich
in point of numbers, embraces a goodly variety. Jabiru, Myc-
teria, Ciconia, Grus, Ardea, and Phoenicopterus are represented ;
yet there is no record of the spoonbill (Ajaia) or of the ibis
(Guara), both of which have been taken in the flesh well to
the northward of Rancho La Brea.

Grouse, quail, and meleagrines have been taken in various
of the deposits under discussion; yet we find there none of the
eracid birds such as Ortalis which occurs at present along the
Rio Grande valley of Texas.

The absence of the above-mentioned species, particularly the
Raptores, from all the bird-bearing deposits thus far known to
North America becomes very striking in view of the large num-
ber of instances recorded of the southward retraction of species
and genera since the Pleistocene period. It is possible that the
forms mentioned above were more sensitive to the cold and were
driven southward before the deposition of the Pleistocene strata
thus far explored, or that they were, on the other hand, more
tropical species that have only in Recent time diffused north-
ward to their present range. Gyparchus is reported from the
Pleistocene caves of Brazil by Winge (op. cit.) which fact would
support the latter hypothesis. Polyborus cheriway would fall
in the same category with Gyparchus, being represented in the
asphalt by its close relative Polyborus tharus. The same is per-
haps true of the Recent species of Geococcyx found in the Son-
oran zone of California at the present time but represented in
the asphalt only by a longer-shanked form which can scarcely be
considered as the direct ancestor of the living Geococcyxr cali-
fornianus. The species from the asphalt may be identical with
one of the species of Neomorpha from South America, comparison
between them having been thus far impossible.

Approximately eighty species of true columbine birds inhabit
the Americas today and many of the species are forms which
feed on the ground and which congregate about water holes
to drink; yet there is no specimen in all the material examined
which is referable to this group. The commonest species in the

1912] Miller: Pacific Coast Avian Palaeontology 99

coast region today is the turtle-dove (Zanaidura macroura), a
bird of wide distribution over the Austral region and even to
the tropics. Its habits and its abundance are such that one can
scarcely coneede as possible that it could have been present
during the deposition of the Pleistocene beds of Rancho La Brea
and yet not be preserved as a fossil.

Palamedea and Cariama have in their present home in South
America a distribution and habits not unlike those of the stork,
Eucenura. Both groups are, however, absent from the fossil
collections. The peculiarly isolated positions which these birds
occupy in the scheme of classification, as well as the measure of
uncertainty as to their proper location systematically, makes any
hight that palaeontology might throw upon the subject especially
desirable. Most careful search was made therefore to see if any
part of the skeleton of these birds had been preserved, but
nothing was found that resembled either species in the smallest
degree.

The parrot order, abundant a few degrees to the southward,
is unrepresented in the deposits. This may be due to the fact
that the only forest fauna which we have preserved to us (cavern
deposits) is of Upper Sonoran and lower Transition zones, and
thus local conditions may have been unfavorable for these birds.
On the other hand, as suggested in the case of Ortalis, they may
have been driven southward before the deposition of any of
the beds thus far explored.

All trace of true struthious birds is lacking in the ecollec-
tions also. The northward diffusion of such forms as the eden-
tates and Hydrochoerus among the mammals, the presence since
early Pleistocene time of rheas in South America, the occurrence
of tridactyl struthionids in the Pliocene of northern India, and
of Struthiolithus in the superficial deposits of northern China,
increase the probability that some day the discovery of true
struthious birds in North America will be announced. The most
potent factors that would bring about such distribution are
first, the possible northward diffusion of rheids along with eden-
tate mammals and, second, the passage of Struthiolithus or its
relatives along the line of proboscidean invasion from Asia by
way of the land bridge to Alaska.

100 University of California Publications in Geology [Vou.7

The earliest occurrence of rheids in South America is in
strata now referred to the Pleistocene (the Pampean of Monte
Hermosa). If the group had reached that continent by way
of the Antarctic at an earlier time, their bones would probably
be found with the primitive mammals supposed to have been
derived from Australia and known to us from the Santa Cruz
beds. The rheas with their true struthious characters could
hardly have originated de novo in South America; henee the
conclusion that they entered from the north, as did the true
cats, deer, elephants and other mammals of northern or Old
World origin.

Cope’s discovery of Diatryma** in the Wahsatch Eocene of
New Mexico was at first considered as fixing a very early date
for the group of Struthiones in the New World. Lueas,*? how-
ever, places this unique specimen in the group of Stereornithes
with the great Phororhacos of South America (Miocene of Santa
Cruz). <A wide gulf exists between the ostriches and these
South American phororhacids. The latter are more probably a
Joeal development brought out in response to the peculiar con-
ditions prevailing there in Tertiary time. There existed in South
America no large carnivores among mammals until the northern
incursion of machaerodonts and the true felines in relatively late
eeological time. Edentates were left free to develop to the
tremendous extent noticeable in the South American Tertiary
and Quaternary. In this region of low pressure among mam-
mals there developed unrestrained the predatory bird Phoro-
rhacos, to occupy a bionomie place like that of the mammalian
carnivore. The reference by Lucas of the North American Dia-
tryma to the Stereornithes is tentative. He states the case in
these words in part: ‘‘Still there are sufficient resemblances be-
tween the two to warrant the suggestion that if material comes
to light it will be found that the affinities of Diatryma are with
the Stereornithes and not with the Dromaeognathae.”’

In view of the indeterminate character of the single specimen
of Diatryma where its relationship between two such distinct

34 Cope, E. D., U. 8. Geol. Surv. Terr. W. of 100th Merid., vol. 4, pt. 2,

p. 69, 1876.
35 Lueas, F. A., Proc. U. S. Nat. Mus., vol. 24, p. 545, 1903.

1912 | Miller: Pacific Coast Avian Palaeontology 101

eroups as the Struthiones and the Stereornithes are in question,
it would seem that the chief value of Cope’s discovery is to
show us that a group of gigantic terrestrial birds ean inhabit
a region and leave almost no trace of their occupation of that
part of the globe. The same fact is pointed out by Eastman*®
in his discussion of Struthiolithus and the distribution of the
Dromaeognathae. Before the discovery of this species in the
superficial deposits in the mountainous regions of northern
China no one would have surmiséd that this great area to the
north of India was ever inhabited by struthious birds. Why not
expect, then, with perfect propriety, that some day the path of
immigration of hea into South America may be traced in yet
undiscovered deposits of North America ?

The other principle which encouraged the search for rheaids
in the asphalt, that of a northward migration of southern forms
in the Pleistocene, is applicable whether Rhea be considered a
product of the southern continent or not. Among mammals we
have the northward diffusion of the various edentates and
Hydrochoecrus, which may be considered products of southern
soil, and we have also a re-entrance from the south of certain
forms which are Neogaeic by adoption. For example, we may
look upon Didelphys as having performed such migration. The
objection might be raised that the tropical belt would act as a
barrier preventing the plains-dwelling Rhea from retracing its
steps, but such an objection is reduced to questionable validity
by the presence of true rheids in the cavern deposits of Brazil.

The following is a list of lipotypes which are considered by
the author as of particular interest:

List or LIPOTYPES

Gavia, sp. Palamedeidae—all species
Gyparchus papa Auct. Cariamidae—all forms
Thrasaétus harpya Auct. Phororhacidae—all species
Polyborus cheriway (Jaquin) Gaura, sp.

Cracidae—all species Plegadis, sp.

Columbae—all species Ajaia, sp.

Psittaci—all species Geococeyx californianus (Lesson)

36 Hastman, ©. R., Bull. Mus. Comp. Zool. Harvard Coll., vol. 32, p.
127-144, 1898.

102 University of California Publications in Geology (Vou.7T

Possible Influences Conditioning Present Distribution of Cer-
tain Groups.—In considering the relation of past to present dis-
tribution of American birds, at least two principles present them-
selves in explanation of the apparent southward retraction of
certain forms since Pleistocene time. The first is typified by the
case of Polyborus tharus. May this species not have been driven
southward across the equator after the time of formation of
the asphalt deposits by the advance of a cold period such as sent
the mammals of the Ovibos zone as far south as Big Bone Lick
and Conard Fissure ?

Extremes of climate due to the presence of the ice sheet are
thought by Allen** to have given rise to the periodical move-
ments of birds which finally merged into the present seasonal
migration. The polyborine under discussion may thus have been
driven southward, but lacked the incipient migratory instinet and
furthermore failed to return northward upon the amelioration
of the climate. This failure may have been due to the presence
of more virile species blocking the return path, or it may have
been due to the limiting tendeney of the torrid zone which it
would have had to recross in a return to the north. No record
of the true Polyborinae has yet been found in the deposits of
the southern hemisphere to correspond with the Pliocene Palaeo-
borus of New Mexico or to extend the occurrence of the group
even back to the Pleistocene, as the Rancho La Brea material
does so abundantly for the northern hemisphere. If, on this
slender thread of negative evidence, we assume that the group
arose in the North Temperate Zone, the explanation suggested
above seems a plausible one. The distribution of Circus, Geran- .
oaétus, Sarcorhamphus, and Hurenura would further uphold this
view of the question. These birds are typically of the southern
hemisphere in latitudes to the south of the tropics or at high
elevations and the Tierra Caliente would act as a more or less
effective barrier to their northward dissemination.

The second hypothesis offered is that the returning annual
isotherm has never yet reached the point at which it stood during
the deposition of the fossil remains. Sinclair (Op. cit., p. 19)
links the Potter Creek Cave deposits pretty closely with the

37 Allen, J. A., The Auk, vol. X, No. 2, Apr. 1893.

1912] Miller: Pacific Coast Avian Palacontology 103

Upper San Pedro series of marine deposits and the San Pablo
Bay oyster beds at Rodeo. These shell deposits are considered by
western palaeontologists to represent a time of higher average
annual temperatures than prevail in the region at present. The
eases of Morphnus, Micropallas, Geococcyx (*?) and Pavo make
a strong aggregate in favor of this theory. To harmonize the
eases of Circus, Polyborus, Sarcorhamphus, Geranoaétus and
Ciconia with those of the more tropical species, it would be neces-
sary to assume nothing further than that these forms, since the
partial ameloration of the clmate, had developed powers of
resistance to cold and had extended their ranges to the southward
instead of remaining intertropical species. The extension of
range took place from the tropics southward instead of to the
northward again because of overcrowded conditions in the north.
The advance of arctic cold toward the equator would drive north-
ern animals into narrower and narrower quarters, while the
forms of the southern hemisphere, under like encroachment of
the antarctic, would experience the opposite effect. The conver-
gence of all the Boreal species into the Austral on the continent
of North America would be in effect like crowding the basal con-
tents of a cone into its apex. The result would be an enormous
intensification of the natural attrition of species upon species
with a resultant stimulus to the surviving form. In the southern
hemisphere conditions would be reversed and the advance of
polar cold, whether synchronous with or alternating with the
northern fluctuations, would have much less serious effect. As-
suming the various faunal zones to be fully populated, the driv-
ing of the Patagonian fauna into the wide expanse of Argentina
and southern Brazil would serve to dilute greatly the Boreal
fauna without materially disturbing the Austral. A form that
had been obliged to flee the rigorous conditions resulting from
an advance of the cold in North America might find, upon the
return of milder conditions, that the path of least resistance to
expanding range from the tropics led toward the south.

Bird Remains as Indicators of Climatic Conditions.—Certain
appearances in the deposits at Rancho La Brea might be inter-
preted as evidence that the climate during deposition of the beds
was warmer and more moist than it is at present in the region.

104 University of California Publications in Geology [Vou-7

The fauna is certainly a rich one and embraces a considerable
variety of ungulates of large size which were dependent on a
goodly supply of grass and browse. Purely local conditions of
dainage may, however, have brought about such a condition. In
the fickle streams of the southwest such’ change of bed may occur
in a single season and a deposit laid down under conditions of
abundant moisture amounting almost to a peat formation may
be left high and dry after a severe freshet to suffer a reversion
to almost desert condition. Relatively few of the anserines are
found in the collections from the asphalt. Geese of the Recent
species become almost upland forms during the rainy season
when grass is abundant. Hu.renura is, according to Hudson’s
account in Naturalist in La Plata, a plains-dwelling form of the
open pampa at some times of the year. The sand-hill crane,
Grus canadensis, is notably a plains feeder in the winter and
spring, while the great blue heron, Ardea herodias, has been
seen by the author on the dry hillsides in midsummer seemingly
in pursuit of grasshoppers. The presence of these birds in the
asphalt in the limited numbers found is not then a_ positive
indication of open water or of even marshy ground. The water-
worn fragments of wood and the leaves in bedded deposit are
such as occur in small steams of the region today when the
streams may be more or less intermittant. A rich and varied
mammalhan fauna is taken by some writers as an indication of
mild climatic conditions. Such conclusion seems scarcely war-
ranted, however, in view of the present conditions in the desert
parts of the world. The writer found deer abundant on the
open and thorny desert of Lower California in the region of
Cape San Lueas. On the mainland of Mexico, in the desert of
Sonora, deer, peeccary, and mountain sheep are abundant. The
accounts by Roosevelt of game distribution in Africa indicate
an abundance and a great variety of game in almost desert
regions of that continent. On the Mohave, the Colorado, and
the great Nevada deserts, the most ephemeral pools of water,
even when highly impregnated with alkaline salts, are the resort
of multitudes of waterfowl, while Cope and Shufeldt describe
abundant life in the region near Fossil Lake on the Oregon
Desert.

1912] Miller: Pacific Coast Avian Palaeontology 105

There is some very credible evidence that the mammals en-
trapped in the asphalt pools were in part attracted to the locality
by water. Over the top of the asphalt layer there may accumu-
late after a shower a stratum of fairly pure rain water, so little
does the viscid asphalt mix with the water. Such an accumula-
tion remains in the impervious basins until evaporated by the
heat of the sun, without loss by seepage through the oil-impreg-
nated earth. Pools of water suitable for the use of cattle and
horses thus remain impounded in natural reservoirs after adja-
cent streams have vanished. Natural reservoirs are of such im-
portance in the southwestern deserts as to have received the local

Spanish name of ‘‘tinajas,’? and wild mammals of the desert
come from long distances to drink at them. Such conditions
would tend to concentrate the remains of mammals of a poorly
watered region and furnish the asphalt trap with scores of
victims which otherwise would have escaped.**

Summing up the evidence of a warm, moist climate during
the Pleistocene, we have the following points, all of which are
inconclusive :

1. The presence of species whose nearest relatives are at
present more tropical in distribution. .

2. The presence of an abundant fauna which is suggestive
of favorable conditions of climate. ~

3. The presence of aquatic species and of waterworn chips
laid down in places now dry but showing no great changes in
topography.

4. The suggestion that the mammals of Rancho La Brea were
in some measure led to the region by the presence of water.

Time Relations as Suggested by a Study of Bird Remains.—
Osborn divides the Pleistocene period into three. great time
subdivisions, namely, Pre-Glacial, Glacial and Post-Glacial.**
The Glacial again shows evidence of division into five periods
of fluctuation, during which the ice cap oscillated northward
and southward with the changing isotherms. The period also
represents a time of high elevation of the land surface in general

38 See Darwin, C., Journal of Voyage of H.M.S. Beagle, 1845 (New
ed. 1909), pp. 128-130.

39 Osborn, H. F., The Age of Mammals. New York, 1910.

106 University of California Publications in Geology (Vou. 7

as compared with the Pre-Glacial. The Post-glacial epoch was
characterized by an ameliorated climate and a depression of the
land surface. Great river floods and large lakes were the result
of this amelioration, and extensive fluviatile and lacustrine de-
posits appear, while the previously restricted species of verte-
brates spread out over parts of the country that were formerly
covered by the ice cap.

The faunas of the time are divided by Osborn into three lfe-
zones which are distributed through the Pleistocene, but do not
coincide with the three time divisions as given above. They do
not necessarily represent consecutive faunas, but rather faunas
from different topographic divisions which, in some respects,
overlap each other, though in the main consecutive. Charac-
teristic mammals have given the names to these zones as follows:
Equus Zone, a plains fauna partly earlier than and _ partly
synchronous with the second, the Megalonyx Zone, which was
a forest and meadow fauna mainly of mid-Pleistocene time. The
third, or Ovibos Zone, is an impoverished fauna, perhaps cor-
responding with the Arctic and Tundra period of Europe and
synchronous with the last great glacial advance, the period of
maximum glaciation, which is recorded in the great terminal

moraine.

RELATIONS OF SEVERAL PLEISTOCENE MAMMALIAN Horizons; ADAPTED

FROM OSBORN

Equus Zone Megalonyx Zone

6—Kansas_ Pleistocene, several 9—Big Bone Lick, Ken.

localities. 8—Samwel Cave, Calif.
5—Lake Lahontan, Nev. 7—Potter Creek Cave, Calif.
4—Fossil Lake, Ore. 6—Washtuena Lake, Wash.
3—Rock Creek, Texas. 5—Rancho La Brea, Calif.
2—Hay Springs, Neb. 4—Ashley River, 8. Carolina.
1—Peace Creek, Fla., Late Plio- 3—Frankstown Cave, Penn.

cene or Early Pleistocene. 2—Port Kennedy Cave, Penn.

1—Afton Junction, Iowa.—lst in-
terglacial stage.

Ovibos Zone
4— Alaska Ground Ice.
3—Conard Fissure, Ark.
2—Seattered middle west.
1—Big Bone Lick, Ken.

EE —————

1912] Miller: Pacific Coast Avian Palacontology 107

The exact time-relations between the several faunas is not
determinable, and the overlap of one column upon another is
purposely indefinite. The Equus fauna is considered in part
older than the Megalonyx fauna and this in turn than the
Ovibos.

It must be stated also that the study of mammalian remains
from Rancho La Brea, from the caves of California, and from
Fossil Lake, Oregon, is still being actively pursued and the list
of species revised. Any statement of time-relations must be
considered as purely tentative. Few investigators have had so
wide and so comprehensive an acquaintance with the mammalian
palaeontology of North America as has Professor Osborn; hence
it is considered in this connection that his chronological arrange-
ment of the various mammal-bearing horizons represent the
truth as nearly as we have yet arrived at it.

It will be noted that the Fossil Lake horizon is placed by
him midway in the tabulation of the Equus Zone fauna while
Rancho La Brea and the caves occupy the middle and upper
parts of the Megalonyx Zone. Thus Fossil Lake is to be con-
sidered as the earliest Pleistocene horizon on the coast produc-
tive of avian remains.

If we apply the criterion of percentage of extinct forms,
the evidence furnished by the avian remains would indicate
a different time-relation than that suggested by Professor Os-
born. The various horizons here discussed show the following
sequence when arranged according to the percentage of Recent
species of birds recorded fossil:

Rancho La Brea still living
IBlOSSNMU GK Coarse eee ee ee reee eee 7 still living
still living
Samwel Cave _..0.....20...:1.:esesceeeee still living
Hawver Cave ................ still living

The application of this principle in the case of fossil birds
seems, however, less accurate than in the case of mammals when
we consider the migratory nature of many bird species. The
Fossil Lake fauna according to this basis of estimate would
appear to be younger than that of Rancho La Brea. A glance
at the list of species from Fossil Lake shows, however, the large

108 University of California Publications in Geology [Vou.7

percentage of migratory forms such as the anserines and the
pygopodes. These birds by their migratory habits are rendered
largely immune to the effects of climatic change that might
have brought about extinction in such forms as the raptors and
the secratchers. Ten of the fifteen extinct species recorded from
Fossil Lake belong to genera which are at present non-migratory
in the region.

Whether or not these genera were migratory during Pleisto-
cene time is, of course, a matter of pure conjecture. Allen*®
suggests that it was during the Glacial Epoch that the migratory
instinct was indelibly impressed upon birds by the pronounced
seasonal contrast prevailing at that time. Whether the instinct
was at that time incipient or real, it seems proper to conclude
that those genera which now display it are the ones which would
have profited by its initial operation and have escaped extinction.

There presents itself, then, the very potent suggestion that
the relatively small proportion of extinct forms represented in
the Fossil Lake horizon is due to the fact that many of the
genera there represented possessed or else developed the migra-
tory instinct and were preserved except as influenced by other
factors.

The remaining four horizons may more properly be com-
pared as to age upon the basis of percentage of surviving species,
and such comparison bears out the conclusions reached by Os-
born in his study of the mammals.

Causes of Extinction of Birds—After a consideration of the
varied and in many respects remarkable avifauna of Pleistocene
times, it is natural that the causes of extinction of these forms
should hold an important place in our attention. Why should
we now have but two eagles in southern California where five
once flourished? Why does but one condor remain of the five
species found fossil? The large phase of the variable Pleistocene
Haliaétus has withdrawn toward the north into British Col-
umbia and Alaska, while Phoenicopterus, the ciconids, Polyborus
and the morphnine eagles have withdrawn to the southward.

The gigantic Teratornis disappeared, leaving no near relative

40 Allen, J. A., The geography and distribution of birds, Auk, vol.
10, No. 2, Apr. 1893.

1912] Miller: Pacific Coast Avian Palaeontology 109

to represent the family among the Cathartiformes. How late
did this great bird persist, and did that important factor, man,
have anything to do with his disappearance? According to Dr.
C. Hart Merriam,*! the Me-wah Indians of California have a
legend concerning a gigantie vulture, Yel-lo-kin, so large that
he was able to capture the condor and carry him up through a
hole in the sky. The bird myths of these Indians indicate a close
acquaintance with the California species. It may be that Tera-
tornis persisted until the arrival of man upon the scene, and thus
gave rise to the Mew-wah Indian myth of Yel-lo-kin.

Granting the possible truth of such an assumption as the con-
temporaneity of man and Teratornis, the primitive human animal
could have had but little cause to direct his efforts against the
large raptorial birds. His meagre offensive armament would
probably have availed him but little in any event. Thus the
only influence he would have been likely to exert would be but
the indirect effect through the extermination of large mammals.
The possibility of man’s having exerted any such influence on
the lives of avian species seems remote, in view of the negative
evidence afforded by the absence thus far of human remains
from western horizons of undoubted Pleistocene age.

Direct extermination, or the sharpening of competition, by
incursions of Old World forms, is a theory without the support
of any tangible evidence in the ease of birds. The procyonids
and Didelphys are of long standing in America. Felines would
greatly influence the larger birds by direct attack either upon
the bird or its nest. It seems highly improbable, then, that
birds could have been directly influenced by man or the other
mammals, but that the chief relation of mammals to the large
birds was in the dependence of the latter upon the former for
food-supply.

As has been pointed out in an earlier paper,” the large rap-
torial birds depended in a dual respect upon the large mammals.
First, these birds fed upon the bodies of either carnivores or
herbivores dying of whatever cause; second, the vulture fed upon
the rejected portion of the carnivore’s kill. Thus, any factor

41 Merriam, C. H., The Dawn of the World, p. 163, 1910.
42 Miller, L. H., Univ. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 2, 1910.

110 University of California Publications in Geology (Vou.7

which tended to reduce the numbers of either group of mam-
mals must have reacted also upon the large birds of prey.

It is not at all improbable that the things which brought
about the extinction of Pleistocene mammals were also directly
operative in bringing about the extinction of many species of .
birds. Non-raptorial birds, except where migratory, would re-
spond to chmatic changes very much as did mammals. Osborn
makes suggestions regarding the mammals as follows:

‘‘the Glacial period in North America originated certain new con-
ditions of life which directly or indirectly resulted in extinction,

‘“These conditions include diminished herds, enforced migrations, the

possible overcrowding of certain southerly areas, changed conditions of
feeding, disturbance in the period of mating and reproduction, new rela-
tions with various enemies, aridity, deforestation; in short, a host of

indirect causes.’ 743

Disease, in all probability a factor in the extinetion of some
mammals, may likewise have been the determining influence in
the case of certain birds. During the winter of 1908-9 in south-
ern California, the bodies of thousands of sea-birds were cast
up on the beach within a comparatively short time. Many of
these specimens were examined by Dr. F. C. Clark of Los An-
geles and by the author. The intestines were found filled with
tape-worms. Mildness of the weather coupled with the profound
emaciation of the birds indicated that death was not due to
violence or sudden cause. While the presence of parasites may
not have been the only influence leading to death, it was, in all
probability, an important and possibly the determining factor.

If, as is so variously suggested, the rainfall is now much
less than it was during the Pleistocene, the influence upon bird
life may have been effective over wide areas through the several
factors of food, shelter and nesting sites. Pavo and Meleagris,
although not always confined to wooded country, are both forms
which might have been strongly influenced by deforestation.
The morphnine eagles, with the possible exception of Geranoaé-
tus, are forest-dwelling birds. The local extinction of these birds
in California may have resulted from a thinning-out of the

forests. >

43 Osborn, H. F., The Age of Mammals (New York, Macmillan, 1910).

1912] Miller: Pacific Coast Avian Palaeontology ul

Development of gigantic size in the eathartids is in effect
a case of over-specialization in that it works frequently to the
detriment of the species. The condors of today are of such
unwieldy size that, after a full meal, they experience much diffi-
culty in taking wing from low ground. This fact is reported
to have caused the destruction of many individuals which had
been led to alight in places from which they could not rise again
into the air. Teratornis must have attained a bulk almost thrice
that of the condor if we may judge from coracoid and furcula.
The suggestion conveyed by the sternum is that the pectoral
muscles were not so heavy in proportion, yet the weight of the
bird must have been far greater than that of the condors. The
nature of its food was such that it must have come to the ground
to feed. The effort to rise again, gorged with food, must have
been a severe tax upon its strength, and slowness in taking wing
may have subjected it to frequent danger. The high, compressed
beak of Teratornis resembling the eagle’s in form, though struc-
turally cathartine, indicated the extreme of specialization. The
large body size, likewise a phase of specialization, may have mili-
tated in the end against the life of the species.

The principle of specific decay or senility of species as a
cause of extinction may have suffered somewhat through the too
frequent application of it by the palaeontologist, yet there often
appear cases in which no other factor seems adequate to explain
the loss of a species. Certainly the intersterility of species would
lead to inbreeding with its attendant ill effects. Incipient strains
of intersterility within a species might, where geographically
restricted, lead to the more rapid deterioration of the stock;
generation upon generation of individuals, like the succeeding
generations of somatic cells, become less and less virile until the
species would decline in a manner comparable to the senile decay
of the individual. The rapid decline of certain of the less con-
spicuous species of Hawaiian birds, such as Palmeria and Chae-
toptila, seems almost of necessity the result of such depleting
influence. How effective this factor was in robbing us of many
Pleistocene birds it is of course impossible to estimate; it would
seem proper, however, to look upon it as possibly a contributing
cause.

a University of California Publications in Geology [Vou.7

TABULAR ARRANGEMENT OF West-AMERICAN PLEISTOCENE

AVIFAUNAS
S
Eo
Pe 2
hee is) ©
Ae capone
cana we
ABchmophorusy Wucasie Miner gesese sete see ene eee ee ‘ «
Kchmorphorus occidentalis (Lawrence .............22.---2.---
Colymbus holbelli (Reinhardt)
Colymbus auritus Linnaeus ...............22..--2::0::200--1-- ee
Colybus nigricollis ealifornicus (Heermann) i
Podilymbus podiceps (Linnaeus) ...............-.2.-22----1------ i
Larus argentatus Pontoppidan ................... Caer epee iy
IOP) axe) oyolspnbes TSHoye eNO eee *
Larus californicus Lawrence .................2..2::2--:010e10e0e %
Tarus ores onus HS ut el cites ence eer ener 2
Dams) philadelm nia s(Or dl) eeeeece ses ce cress ce oereee ore eeeeeeseeseee %.
Gaby FeH oro (Al ISP oyhate) se i
Sterna? eleoans! <Gamibel poets peeee eee eee eee *
Sterna forsteri Nuttall -................. Se ee eee ~
Hydrochelidon nigra surinamensis (Gmelin) ................ at
Phalacrocoraxsmacnopusi( Coe) messes seeeree see seerteee eee s
Pelecanus erythrorhynchos Gmelin .... #
Lophodytes cucullatus (Linnaeus) 2
Anas platyrbynchos, Wan ae sie ssessee sense ese eeeenecna sates i
Chaulelasmus streperus (Linnaeus) ..............22--2::-2:-20--++ a
Marecasamericama, (Grn elim) iicecseeseneecesceesteneeeeesseeeeessveaes 4
Nettion carolinense (Gmelin) -.......2222....2222..---220000--2000----- 3 =
Querquedula discors (Linnaeus) ..............22..22:22---0002+ ts
Querquedula cyanoptera (Vieillot) -.........22.22..2..210:--++ *
Spatula clypeata (Linnaeus) .............2..22..22.21:22:02eeeee %
IDENIIEY EyGineh. (Orbis tcyits)) eee eee ee ee ee ee ‘a
PATIIXG SONS (MIMI CUS) ies seca s ecto seca oe eee eee eee seeeeeenerceeeeess *
Mianilam-v allasimerray (Wall Som) esses renee oeeeeeeeeeeseeeeeseeeaenes i
(Ojbnmregviley atelemanalyrey (CE suakel hay) er *
Harelda hyemalis (Linnaeus) ........... #
Erismatura jamaicensis (Gmelin) *
Anser condoni Shufeldt, <3 secs aeecre eee ease %
Anser albifrons gambeli Hartlaub’ -... =... as
Branita’ hiypsibata (Cope) <..-222 cee cee “s
Branta, canadensis, ((iimmaeus))) 222.22 2ce2cc.2eceessceecseeeeeeee tet
Bramtary (ropa nnathel cites cceeeeesseneseeree seen teeceeeeeee tee i
Chen hyperboreus (Ballas), 222 ~
Olor™palorepomus) (Cope) sere ren eeete eee eee ig
Indeterminate amserine 2.20222 oeease octane ceeseene eee a
Imdeterminate: anserine: 22c2ececcesceceeeseseee ree eee #

° ah

1912] Miller: Pacific Coast Avian Palaeontology ak}

S
S f
wn O
A 2
aise fie ©
a5 E Es
Zee eg F 3
Saaam e
Indeterminate anserine ....................-...- x
Phoenicopterus copei Shufeldt be
Ciconia maltha Miller .......2....22..22....-.:.-eeeseeceeceeceeeeeeeeeeeee yi
Jabiru myeteria (Lichtenstein) -.......2....20...2.0.22..22.------ a
Myeteria americana Linnaeus ..................22---2-----1----002--- *
Ardea herodias Linnaeus ..............2.-22.--:-:::::-esseeeeeeeeeseeees ia
Ardea paloccidentalis Shufeldt —.........0....20..22...22...22022---- =
Grusemimor Maller... 22 o2..--.ccccec-eoeeaecevederecnseneeegeceesteseeseeeses *
Grus canadensis (Linnaeus) ........-......2..--.---2----eeeeeeeeeeeoes i
Fulica americana Gmelin ...........22..2..--:-:-e:cceeceeeeeeeeeeeeees =
PHlmacayemimor Shield) 22.2 .222c222cc-ce--2220-22-csecceseeesseecaeseeseeees *
Lobipes lobatus (Linnaeus) -2.......2..2...2.-20..ceec2seeteeeeeeeee x
Oreontyxepictay CD OuUg1aAS) | sos seee ieee ececen c2enessucesaeeseencenesneoes
Lophortyx californica (Shaw) ........2...2::::1::sseeseeeeeeeeeeees
NG OPN OLY 55 SPs esse cies csesceecsoss.ssestssc0egssaiesecsiuessstsevesnvessoesszice ee
Dendragapus obscurus (Say) -.....2.....:::::seeeeseeeeeeeeeeeeeee
Bonasa umbellus (Linnaeus) ...............2...22.:2:0-100200eeeee
Tympanuchus pallidicinectus (Ridgway)
Pedioecetes phasianellus columbianus (Ord) .............. ia
Pedioecetes lucasi Shufeldt -..........20.220.22222202.:0seeseeeeees =
Pedioecetes nanus Shufeldt ..........20.22..22:.2::22::e1eceeeeeeeeeeeee #
Ralaeotetrix gilt, Shutelat 222222 222ece.oe ee scceeeecceeee le *
Indeterminate. odontophorid -................-..:c2s--sssseeceeeseoeeo-= aes
ICES CSE eae TS SY) 0 ane eee ee ee iD ta *
pao) Calatormicus: Maller = 222. y2c..c-sscceansecce-nesenececeecneeneteseree ie
Gymnogyps ecalifornianus (Shaw) .........2....::.:::::1:ee
Gymmopypssamplus Mallen se 222222 ctcc.cecceues-2cscsaeececseca=a ae
Sarcorhamphus clarki Miller -..........2..2..2202:::e::-eseeeeeeeeee ig
Cathartornis gracilis Miller —.....0.2...20220.202222:eseesceeeeeeeee a
leisto gyms: rex: Maller ago. 2c ccss eco ceeewceeeeutcestvssseeeettsess
Cathartes aura (Linnaeus) ...........2...2..2-:2:cssseeeeeeeeeeeeees Pe
Catharista occidentalis Miller -...22...20.202202.20.2:.2.0.e01ee0-e- ia
Catharista shastensis Miller -
Teratornis merriami Miller .
Elanus leucurus (Vieillot) =
Cireus hudsonius (Linnaeus) -......2..22.22-2-:.2:e1eeeeeeeeeeeees ne
OTT C US ria |) seperate ae eve eo oe cnn eee >
PAC CUPULET Velox (IWS OM) beets See eres rere crete zsueseee
IBywHeYo) Joxepeeebicy ((Esenelbia)) ee
Buteo swainsoni Bonaparte (2?) -2......2.22.-.-:21:::-0000----
JMR 0) AS] Oe cee oe Ee as
Archibuteo ferrugineus (Lichtenstein) -...............22......-.
*

Aquila chrysaétos (Linnaeus) .........2..22..-2--2:ceeeeeeeeeeeeeeee

114 University of California Publications in Geology [Vou.7

ee Seen
rit ais) ©
4 oa, w
=
@ ¢ 8 g F 3s
Bea ad eS

TNO|uMUE We jolloyepag oy) PVA Gly Se eps z

Je\Cay ville) (rors buh) PSM Ohh ee eo oe if

Haliaétus leucocephalus (Linnaeus) ~.............-.-..-.-.-.-- ta

Morphnus woodwardi Miller -.0.2..20220.00000200002.-2eee-eee ig

Geranoaétus melanoleucus Auct. (?) -....-2-----

Geranoaétus grinnelli Miller -.......2..2.22220..222:.2s:e-eeeeeoe =

CGeranoadeuus straoilise inl er yaseee:ceeeueese sere ceeeees seer eeeenoee *

Haleo mp ere Sm isa Mam Sa eee eee eee ence

IN ENC OSES gene secterec nee ccs vane coer c aoe eee ean eee *

Faleo sparverius Linnaeus .......-.....----2.:--:c--eeeceeceeceeeeeeeees

IBolybonns tharuS acute peseesce eens eee eres eee rece

Aluco pratincola (Bonaparte)

ACS10n walsomiamuss |(UESSOM)) | ee-ceceecnecee sae so eee ree sere eo neers

Asio flammeus (Pontoppidan) -.....-......----c:--:ccsceeceeeeeeees z

©fusasio™ (Glimnaeus))) Seis cease ee

Bubo yan oumiamnis: iGo en) ease eee eee sees

ABU fo) tepvated len int OY UDC v es oe Bee

Speotyto cunicularia hypogaea (Bonaparte) ................ by

Glaucidium gnoma Wagler ....................- eae ee ae

Micropallas whitneyi (J. G. Cooper) ..........22:.2:::2::000200+

INeomorp hay, 2, SPs, .csze-cceec! eons woos cacetonsessee- codes ccastee acca testes *

@olaptesicaterm (Gmelin) Weseeeees essere: sceraeeseuee se saeeeueesenrennes

Otocoris alpestris (Linnaeus) ........-2......-220-2--e1eeeeeeeeeee =

@yanocitita stellleris (Game lim) jee eee eee esesoees

@oryusncorasx Winn Aeus gescec ven -seececestee cece erence -eesereeeseeees

Corvus brachyrhynchos Brebim j2222.22.22222 cesses eee

Corvus annectens Shufeldt. ............20..22.22.-2ee2eeeeeeeeee eee *

Corvus; SP: <:2----<-:-.- oes ceg cass Sen gee oes Pcne cuca ease ee eure *

Xanthocephalus xanthocephalus (Bonaparte) .............. =

Avelaiussoubernator (WWiaeler)) see ssenese eee eeeee eee *

Sturnella neglecta Audubon .-........... oe a

Euphagus cyanocephalus (Wagler) ...........-.-----.----------00-0-

TD jojo) eye b tsp eewarbawle: pO) aub Re U0 hd epeeeee eee eee eee eee i

PAPO] Ot SPs oe caceuzaccecessttesetees fetes suze con teee gue eeser eee see eeeemeretcnee %

Lanius ludovicianus Linnaeus .................c0.ceceeeeeceecneeseee ees

1912] Miller: Pacific Coast Avian Palaeontology 115

BrBuioGRAPHY OF Paciric Coast Fossm AVIFAUNAS

1878. Cope, E. D., Bull. U. 8. Geol. Surv. Terr. iv no. 2, May 3, 1878.
Describes three species of birds from Fossil Lake, Ore.

1892. Shufeldt, R. W., A Study of the Fossil Avifauna of the Equus
Beds of the Oregon Desert, Journ. Acad. Nat. Sei. Phila. no. 9,
p. 389.

1894. Cope, E. D., On Cyphornis, an Extinct Genus of Birds, Journ. Acad.
Nat. Sci. Phila. no. 9, p. 449.

1901. Lueas, F. A., A. Flightless Auk, Manealla ecaliforniensis, from the
Miocene of California, Proce. U. S. Nat. Mus., vol. 24, p. 133.

1909. Miller, L. H., Pavo californicus, a Fossil Peacock from the Quater-
nary Asphalt Beds of Rancho La Brea, Univ. Calif. Publ., Bull.
Dept. Geol., vol. 5, p. 285.

1909. Miller, L. H., Teratornis, a New Avian Genus from Rancho La
Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 305.

1910. Miller, L. H., Wading Birds from the Quaternary Asphalt of
Rancho La Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p.
437.

1910. Miller, L. H., The Condor-like Vultures of Rancho La Brea, Univ.
Calif. Publ. Bull. Dept. Geol., vol. 6, p. 1.

1911. Miller, L. H., Additions to the Avifauna of the Pleistocene Deposits
at Fossil Lake, Oregon, Univ. Calif. Publ. Bull. Dept. Geol., vol.
6, p. 79.

1911. Miller, L. H., A Series of Eagle Tarsi from the Pleistocene of
Rancho La Brea, Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, p. 305.

1911. Miller, L. H., Avifauna of the Pleistocene Cave Deposits of Cali-
fornia, Uniy. Calif. Publ., Bull. Dept. Geol., vol. 6, p. 385.

NotTe.—Since the text of this paper went to press, bird remains have
been found in the Upper San Pedro Pleistocene at San Pedro, Cal., by
Dr. F. C. Clark of Los Angeles. These remains were very generously
presented to the present writer by Dr. Clark, and by permission of the
latter, were deposited in the Vertebrate Palaeontology Collections at the
University of California. Three of the specimens are almost perfect, the
several others are too fragmentary for determination. One specimen repre-
sents an undescribed species of grebe of the genus Achmophorus but in view
of the fact that the active exploration of these beds now going on will
possibly bring to light cther remains of like nature, a description of the
species is thought unwise at present.

Remains of Bison, Equus, a ecamelid, rodents, seals, small turtles, and
sting rays have also been taken from these beds by Dr. Clark and the

writer.
List OF SPECIES FROM Upper SAN PEDRO
Mammals Birds
Equus Aichmophorus, n. sp.
Bison Nettion carolinense (Gmelin)

Camelid Sturnella neglecta Audubon

<a = = SO a

“gh. scleened December 4, 1912"

SIOGRAPHY AND STRUCTURE OF THE.
ESTERN EL PASO RANGE AND THE
SOUTHERN: SIERRA NEVADA |

CHARLES LAURENCE BAKER

DEC LY sae

Nationa| Muse’

UNIVERSITY OF CALIFORNIA PRESS
BERKELEY

Norre.—The Tae of California Publications are oftiered in n exchangé
cations of learned societies and institutions, universities and libraries. Co
all the publications of the University will be sent upon request. For sample C0]
publications and other information, address the Manager of the University Pre
California, U. S. A. All matter sent in exchange should be addressed to T. I
Department, University Library, Berkeley, California, U. S. A.

Otto HARRASSOWITZ R. FRIEDLAENDER & Sony
LEIPZIG BERLIN

Agent for the series in American Arch- Agent for the series in Anand y:
aeology and Ethnology, Classical Philology, aecology and -Hthnology, Botany, Geole
Education, Modern Philology, Philosophy, Mathematics, Pathology, Physiolo
Psychology. Zoology, and Memoirs. ,

Geology.—Anpbrew C. Lawson and JoHN C. Merriam, Editors. Price per volume, $3,

Volumes 1 (pp. 435), HI (pp. 450), III (pp. 475), IV (pp. 462), V (pp. 448),

completed. Volumes VI and VII'‘(in progress). ee

Cited as Univ. Calif. Publ. Bull. Dept. Geol.

Volume 1, 1893-1896, 435 pp., with 18 plates, Price......--.----.--c--cec-eceeceeeeeeeeeeeees far

. Volume 2, 1896-1902, 450 pp., with 17 plates and J: map, price... .-.-ecce ee
A list of the titles in volumes 1 and 2 will be sent upon request.

VOLUME 3.

1. The Quaternary of Southern California, by Oscar H. Hershey .2....---.2-----cscscsesceceseseceeeseoes
2. Colemanite from Southern California, by Arthur S. Hakle. i... ccceccescerenccneceesenene
3. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by ~

Andrew Cs Lawson <...-22-Siececotessvcecceteccteennectengcneetect pnt canal aes Soreeaae Wes oc\Oees a te
4, Triassic Ichthyopterygia from California and Nevada, by John C. Merriam...
6. The Igneous Rocks near Pajaro, by Johm A. Reid. 2.:ccc- cece cca: -ceeeee ee
7. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller
8. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by

Andrew Cy. Dia wen snc. 5 otic cieeetecckdeadbcscencccer-aeecapeescedb vost es at, eeee Toe
9. Palacheite, by Axthur S.. Wake .:..cc25 20 --aseccectececceas cee me!
10. Two New Species of Fossil Turtles from Oregon, by O. P. Hay. Ms
11. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinelair.
Nos, 10 and 11 in one Cover .....-25.f2---scisccs ech cpeene sere ie en

12. New Ichthyosauria from the Upper Triassic of California, by John C. Merriam........
13. Spodumene from San Diego County, California, by Waldemar T. Schaller................
14. The Pliocene and Quaternary Canidae of the Great Valley of California, by
John’ C,- Merriam (tol ci ss ceccca ceca cca enc gen on ate esac aceteee can tase een 4

15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson..........-........: :
16. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam......
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew C.
Pia WOM: 2.222 2ees. cc. oee ck nnn nn -dencnectenen ob =-anecscndhnesbemas mit eeehanas]nge aes + soa ce eR ete tee ia

18. A New Cestraciont Spine from the Lower Triassie of Idaho, by Herbert M. Evans”
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmon
20. Euceratherium, a New Ungulate from the Quaternary Caves of California, by
William J. Sinclair and E. L. Br] O10 Gs. en hennde wtdevontoncennenttecbs inane

21. A New Marine Reptile from the Triassic of California, by John C. Merriam ..
22. The River Terraces of the Orleans Baa, California, by Oscar H. Hershey......

VOLUME 4,

1. The Geology of the Upper Region of the Main Walker River, Nevada, by Dwigh
T. Smith eee he Se ee a eS eel ig ae
. A Primitive Ichthyosaurian Limb from the Middle Triassie of Nevada, by John
CS Mierrietmn: © 2525 rasaecccs ee a eo
Geological Section of the Coast Ranges North of the Bay of San Franciseo, b;
Vi. CO, OSM «nn eneeneneeneee ee ceeteeeececnenecetneneanannennesscenneenennentanesecntancatensessesesmansearaannersnes t
Areas of the California Neocene, by Vance C. Osmont....-...-------2------0--0-----0-=
Contribution to the Palaeontology of the Martinez Group, by Charles E. We:
New or Imperfectly Known Rodents and Ungulates from the John Day Series
Wralliamn Ji Srmelsaiar 2202s ace eee eee cee
. New/Mammalia from the Quaternary Caves of California, by William in
. Preptoceras, a New Ungulate from the Samwel Cave, California, by Eustace

PB urlong oo... seen eenenneneeeeccseeeceeeeeeneneeencseseceneececncnanenensenssnaenancs soseecessseeeennnsncecnnssensennaes ae

Cuero sot

co™~

— ideing
a “i

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 6, pp. 117-142, pls. 8-10 Issued December 4, 1912

PHYSIOGRAPHY AND STRUCTURE OF THE
WESTERN EL PASO RANGE AND THE
SOUTHERN SIERRA NEVADA

CHARLES LAURENCE BAKER

CONTENTS

PAGE

Mpritrs ON CLO pe reas eee 2 CTs a2 ce vecedescesssscasczecedeieceuccsetseseseituis 118
HhemsWrestern: (Hill Paso) RAM Ge 2... eee eecceceecesceeceececceectessceceeseeceeecesezeneeess ae Ulf)
HATE OU SMMC StUCALLONS -2ec-2ceeeee cece caeeeeeecense-eeeecevereesecreeeeceece'seeencenaaeeeeeo---= 119
(CHOSE OLN cree ee 119
Nequence lof Morma tions ccs. e.5 occ ce cee cocccedecce eco entacectseeeentensubecscecsceseceesese 121
The Basement Complex of Metamorphic and Plutonic Rocks ...... 121
Metamorphic Quartzite-conglomerate and Quartz-schist in

VG CRO Chet@ anomie ee ee ees eee eee cee ee bale tecee se ene 121

Intrusive Hornblende Diorite-porphyry —......2...022002-20eceeee- 121

PATCTUIC MIO TIC OUS VOCS) oes. ceece seeker ee rceceteeeec:tesesecsteccsnesceetecee tt eensce 122

The Superjacent Series of Sedimentary and Voleanic Rocks ...... 123

The Black Mountain Basalt FLOW -20..2..2..222.ce:cecceceeeeceeeeeeeeeeeeneeteeeee 12

PANT Usa 11 gees ce ce caecse hs care eee Oh eh! Bes ao, LN etea seats ees Als, 128
PSIUSAEMOURDER SS oe eee te ete ee en en nS 129
ELSIF OTT CAIN GOO Sivan tere mee ees ta Pe Age Sts cece iene esiae gets. 132
Geologic History of the Consolidated Rock Members .................. 132

Geologic History Posterior to the Time of the Deposition of the
Rosamond Series as Inferred from the Structure and

IE Ay ASG AE: 0) 6 kaa en ec ee ea 134
The Two Epochs of Post-Miocene Uplift with the Interven-
ing First Cycle of Post-Miocene Erosion ........................-..- 134
Origin of Red Rock Cafion and Last Chance Guleh .. 134
IVE COM tpg h VU 1M ae oases csr ecco ees ade et ocasecoceteceeceeceeoscasentesceed 236
MheySouthern’ Sierra Nevada 22c-c2c.cceccceeoseseceeecscceeeccoececedeceerserereeeececdeecetae-ocee 137
Miner RAcaATd OM MGOSION SUNLACE foe. c22. 22. ccccceccceeccecceececceecsecesesaeseneceente-ensten 137
Latest Epoch of Faulting, not Affecting the Entire Southern Sierra
OSHA So 5 Nee eo ae Bete ER 139
Dissection of the Sierra Debris Slopes -.........2..2..2..2:c2-cecceeceececeeeeeeeeee 141
ISTIRIININ GD Lay puree nese ceees =e cue deweuctet tite emacs. Suva eswv=ctieaytives slaves seesvescecdosessazesst-ctee lene 142

118 University of California Publications in Geology (Vou.7

INTRODUCTION

Some observations were made on structural and physiographic
features in a section of the southern Great Basin during a recent
reconnaissance conducted for the Department of Palaeontology
of the University of California, under the general direction of
Professor John C. Merriam. Since the main purpose of the
undertaking was the collection of vertebrate fossils, relatively
little time was available for geologic observations. The follow-
ing notes, therefore, are much scattered and can make no pre-
tence to the completeness and accuracy necessary for a strictly
scientific treatment of the geology. However, certain features
were noted which have not been deseribed by previous investi-
gators of the region.

The area examined embraces that portion of the southern
slope of the Sierra Nevada situated between Jawbone Canon,
northeast of Cinco Station on the California and Nevada Rail-
road, and Indian Wells, southeast of Walker Pass and some
miles south of the Inyo-Kern County line. Most of the field
work was done in the El Paso Range, a few miles south and in
en echelon relation with the above-designated section of the
Sierra Nevada. Only that portion of the El Paso Range west
of the summit of Black Mountain was studied.

The writer is under great obligation to his field associates,
Messrs. 8. H. Gester, George E. Stone, and John Guintyllo, and
for microscopical examinations of rocks to Professor George
D. Louderback, Mr. R. G. Davis, and Mr. John R. Suman.
Acknowledgements are also due to Professor Andrew C. Lawson
for information concerning erosion cycles and periods of de-
formation in the southern Sierra Nevada.

1912] Baker: Western El Paso Range 119

THE WESTERN EL PASO RANGE
PREVIOUS INVESTIGATIONS

The only geologists who have written of the western El Paso
Range are G. K. Gilbert,t H. W. Fairbanks,? and the writer.’
The easternmost portion of the range will be described by F. L.
Hess in the forthcoming Randsburg folio of the United States
Geological Survey.

GEOGRAPHY

The El Paso Mountains form a low, even-crested, and, for the
most part, maturely dissected ridge lying en echelon with the
southern Sierra Nevada along the northern boundary of the
Mohave Desert. They trend east-northeast and west-southwest
for their entire length of twenty miles and are about six times
as wide near their eastern extremity as near their western.
They reach their highest summit in Black Mountain, a short
distance west of the region mapped on the Randsburg topo-
graphic sheet of the United States Geological Survey. Eastward
of Black Mountain the range continues into the region of the
northwestern portion of the Randsburg sheet and comes to an
end about three miles east of the boundary line between Kern
and San Bernardino counties and some six to eight miles north
of the mining camp of Randsburg. The southern base of the
El Paso Range is skirted by the California and Nevada broad-
gauge railroad, a branch of the Southern Pacific System.

The El Paso Mountains are separated on the north from the
Sierra Nevada by a southward-sloping alluvium-mantled plain
ranging in width from six or eight miles east of Walker Pass
to less than two miles at the west, north of Cantil station on the

1 Report on the geology of portions of Nevada, California, and Arizona,
examined in the years 1871 and 1872, Geog. and Geol. Expl. and Surv. west

of the Hundredth Meridian, vol. 3, pp. 142 and 143, 1875.

2 Notes on the geology of eastern California, Am. Geol., vol. 17, pp. 63-
74, 1896.

3 Notes on the later Cenozoic history of the Mohave Desert region in
southeastern California, Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, pp. 333-
383, 1911.

120 University of California Publications in Geology (Vou.7

California and Nevada Railroad. This whole depression, to the
very foot of the El Paso Range, is mantled with debris derived
from the Sierra Nevada, The northward slope of the El Paso
Range is longer and less precipitous than the southward slope,
which rapidly falls off to the south into the depression occupied
by Kane ‘‘dry lake.’’ The southern base of the mountain ridge
forms'a remarkably even and straight line (pl. 8, fig. 1). Above
this base-line the summit peaks rise to altitudes of less than one
thousand feet on the west and to more than three thousand
feet on the east. The western portion of the mountain mass is
separated into two subsidiary ridges by the deeply-incised
tributaries of Red Rock Canon and Last Chance Gulch.

The mountain ridge is cut transverse to its longer axis by
three deep and narrow canons, named in order from west to east,
Red Rock Canon, Last Chance Gulch, and Goler Gulch. These
canons head in the north flank, cross the range, and drain into
the Kane depression to its south. There are springs in the beds
of these cafions which furnish a surface flow for a few hundred
yards in places where the bedrock is close to the surface of the
stream bed, but in none of them is there a permanent stream
with powers of continuous erosion.

The upper tributaries of the canons, situated in the compara-
tively slightly indurated sedimentary beds of the north flank,
follow in general the strike of the strata (pl. 8, fig. 2, and 10,
fig. 1) parallel to the longer axis of the range, and have excavated
rather wide and flat basins both north and south of Ricardo
post-office (pl. 9, fig. 1 and fig. 2) in Red Rock Canon. But upon
entering the more resistant plutonic and metamorphic rocks,
which the canons cut through in directions nearly at right angles
to their former courses, the canons both deepen and steepen very
perceptibly (pl. 9, fig. 2), becoming in places almost vertical,
while their beds narrow until in some places they are scarcely
wide enough for a wagon to pass between the rock walls. The
precipitous walls and the narrow bed are especially character-
istic of Last Chance Gulch. That gulch, too, has an extremely
tortuous course where it cuts through the granite. It heads in
tributaries on the southern and southeastern slopes of Black
Mountain and then extends for several miles in a westerly direc-

VINIV: CALIF: PUBL BULLY: DEPT. GEOL. [BAKER] VOL. 7, PL. 8

Fig. 1.—Southward-facing fault searp of the El] Paso Range. Basin of Kane ‘‘dry lake’’
to the right.

Fig. 2.—Interbedded basalt flows in the Rosamond series, north flank of the El Paso
Range. The northwestward dipping strata of the north flank are shown, and also the strike
valleys excavated between the hogbacks of more resistant rock. On the lower slopes in the
middle distance is a terrace of horizontally bedded alluvium. The high peak on the middle
of the horizon is Black Mountain, separated by a depression from the main granite range
on the right.

1912] Baker: Western El Paso Range 121

tion along the strike of the basal beds of the Rosamond series of
sedimentary rocks. It thus separates the range in this vicinity
into two subsidiary ranges, the basalt-capped Black Mountain
on the north and the main granite ridge on the south.

SEQUENCE OF FORMATIONS

The rocks of the El Paso Range may conveniently be divided
into the basement complex of metamorphic and plutonie rocks,
the superjacent series of sedimentary and voleanic rocks, and
the alluvium. The basement complex comprises the rocks of the
higher divides and, with the exception of two minor localities,
of the whole southern flank. The sedimentaries and voleanies,
with the exceptions just noted, are confined to the northern flank.
The alluvium mantles in places all the older rocks.

THE BASEMENT COMPLEX OF METAMORPHIC AND PLUTONIC ROCKS

Metamorphic Quartzite-conglomerate and Quartz-schist in
Red Rock Caion.—The lower narrows of Red Rock Canon have
been cut through a metamorphic series of quartzite-conglomerate,
quartzite, and quartz-schist of unknown age and thickness. This
series comprises the oldest rocks in the western portion of the
range. The quartzite-conglomerate is formed of well-rounded,
milky quartz pebbles averaging less than an inch in long diam-
eter, embedded in a matrix of impure quartzite with a noticeable
percentage of basic minerals which gives the rock a greenish-gray
to dark gray color. Under the microscope the quartz is seen to
form a holocrystalline fine granular mosaic with schistose struc-
ture. About ten per cent of the rock is made up of a green
hornblende, which is also recrystallized. Another slide shows
about as much epidote as quartz, with an irregular vein of calcite
including anhedral grains of a mixture of limonite and hematite.
The quartz includes acicular crystals, greenish-yellow in color,
which are probably epidote. Good slaty cleavage is developed
in portions of this series. Small masses of secondary pyrite are
to be seen in the quartzite.

Intrusive Hornblende Diorite-porphyry.—The metamorphie
series is cut by a mass of hornblende diorite-porphyry. The
main intrusive rock has medium-sized and fairly abundant

122 University of California Publications in Geology [V0.7

phenocrysts of green hornblende and whitish feldspar. The
groundmass is microcrystalline. The feldspar of the pheno-
erysts, making up about fifty per cent of the rock, is andesine, in
large part altered to muscovite, calcite, and quartz. The feld-
spar of the groundmass has about the same composition as that
of the phenocrysts and is also altered and silicified. _ Thirty
per cent of the rock is made up of the green hornblende of the
phenocrysts and groundmass, in fairly fresh condition. Mag-
netite phenocrysts are also present.

The apophyses from the main mass differ from it both in
texture and color. The dike rock is dark bluish gray in color,
with an aphanitie groundmass and lath-shaped phenocrysts of
hornblende, some of which are a half inch in length. Small
masses of secondary pyrite can be seen in the hand specimen.
Under the microscope the rock is seen to be holocrystalline por-
phyritie with phenocrysts making up forty-five per cent of the
total mass. Green hornblende, in large measure altered to
chlorite, makes up forty per cent. Ten per cent is made of
phenocrysts of a monoclinic pyroxine, probably augite. Labra-
dorite feldspar of the groundmass comprises thirty-five per cent,
while the plagioclase of the phenocrysts makes up fifteen per cent.
The feldspars are largely altered to an aggregate of muscovite
and calcite.

Acidic Igneous Rocks.—East of the intrusion of hornblende
diorite-porphyry the southern or main ridge of the El Paso
Range is made up of coarse-grained granite cut by dikes of
pegmatite and aplite. The relations of this granite to the meta-
morphie series and the hornblende-diorite porphyry was not
ascertained. A dike cutting the metamorphic series about one
half mile east of the lower narrows of Red Rock Canon contained
primary oligoclase feldspar, which had been subjected to crush-
ing, and quartz lenses representing either original quartz pheno-
erysts or amygdules. The original groundmass contained quartz
in large amount, which had been recrystallized. An original
erystal of titanite was crushed. A small amount of chlorite was
present in the quartz, and a vein-like mass of epidote, containing
veinlets of quartz, cut the rock. The rock should probably be
ealled an altered quartz porphyry.

1912] Baker: Western El Paso Range 3

THE SUPERJACENT SERIES OF SEDIMENTARY AND VOLCANIC ROCKS

In a previous paper by the writer the extensive bedded de-
posits of tuffs, tuff-breecias, and lava flows on the northern flank
of the El Paso Range were grouped with the Rosamond series
on the basis of lithologie similarity and similar fossil content to
strata farther south in the Mohave Desert originally given that
name by Hershey.*

West of Red Rock Cafion the metamorphies are overlain un-
conformably by a lava flow called by Gilbert an ‘‘orange, massive,
subspherulitie rhyolite.’’ The writer made no examination of
this rock.

East of Red Rock Cafion the quartzite-conglomerate, quartz-
ite, and hornblende diorite-porphyry are overlain unconformably
by a loosely-cemented breccia containing angular fragments of
the underlying rock. The matrix is mainly silicious sand rang-
ing in size up to coarse grit and fine pebbles.

Farther east, where the Rosamond uneconformably overlies
the granite, there is at the contact a pure white, silicious, compact
rock about twenty feet thick, overlain by several hundred feet
of red breccia, with thin interstratified beds of light gray tuff-
breccia, grading up into light gray tuff-breccia.

On the east wall of Last Chance Gulch the basal Rosamond
les uneconformably upon the granite. The basal beds are coarse
water-worn conglomerate with a matrix of dark red granite
arkose and bowlders and pebbles mainly of granite, some bowlders
being as large as a foot in diameter. The immediate over-
lying beds are coarse and of varied hue, sometimes with inter-
bedded red and grayish-white layers, sometimes with cream-
colored or yellow or pink or dark red layers. A short distance
above the base the rounded conglomerate passes into angular
breccia.

The basal sediments in Red Rock Cafion consist of two hun-
dred and fifty feet? of dark red breccia, with thinner inter-
stratified layers of light gray color. Next in the upward succes-

4Some Tertiary formations of southern California, Am. Geol., vol. 29,
pp. 349-372, 1902:

5 All thicknesses given in the following descriptions are only approximate
estimates.

124 Unversity of California Publications in Geology [Vou.7

sion comes a light pink spotted tuff-breccia forming one massive
bed 100 feet in thickness, and cut by two strike faults of fifteen
and fifty feet displacement. The matrix of this bed is a tuff
of a lighter shade of pink than the angular fragments of reddish
lava which it contains. This is succeeded by beds mainly gray
in color with thin interspersed layers of dark red, 150 to 250 feet
in thickness. Then come 300 feet of light gray, rather fine,
poorly stratified tuff-breecia, capped by a flow of vesicular basalt
about fifty feet thick. A second flow of basalt is separated from
the first, at an interval of about fifty feet, by beds similar to those
just below the lower flow (pl. 8, fig. 2).

In the writer’s first description of this section it was stated
that there was but one basalt flow, the outerop of which had
been repeated by a normal strike fault. This statement is now
definitely known to have been erroneous. In the first examination
these basalt flows were studied only in the vicinity of Ricardo
post-office, where their relations are obscured by alluvium. It
was noted that about three-fourths of a mile to the west the lower
flow came to an abrupt end, and taking into consideration the
proved presence of strike faults a short distance below the basalt,
it was thought that the best explanation for the outcrop of two
layers of basalt in the walls of Red Rock Canon was that a single
flow had been repeated by a strike fault fradually diminishing in
amount of displacement towards the west and finally coming to
an end about three-fourths of a mile west of Red Rock Cajfion.
But in reality a wide stream channel was excavated in the lower
basalt flow before the outflow of the upper one, for still farther
west the lower flow suddenly appears and the space in which the
lower flow is absent is filled with much eross-bedded sediments.
The relations here are very suggestive of conditions similar to
those during which the river-channel sandstones and conglomer-
ates were laid down in drainage courses eroded in finer beds of
White River Oligocene age in the Big Bad-lands region of South
Dakota.

Conclusive evidence that these basalts are interbedded flows
and not intrusive sills is furnished by the fact that their upper
surfaces have been eroded and that fragments of the basalt are
locally found in abundance in the tuff beds in close juxtaposition

UNIVE ‘CALIF. PUBL. “BUILE, DEPT, GEOL. [BAKER] VOL. 7, PL. 9

Fig. 1.—Basin excavated by Red Rock Canon in the Rosamonu series above the outcrop
of the higher interbedded basalt flow, at Ricardo post-office. Typieal badland topography
of the Rosamond as well as the mantle of Sierra alluvium covering the bevelled surface of
the northwestwardly dipping Rosamond illustrated by this view. The dissection of the
alluvium and underlying Rosamond is to be noted. Upper surface of upper basalt flow in
the left foreground.

Fig. 2.—Basin excavated by Red Rock Cafon and its tributaries in the lower Rosamond
below the interbedded basalt flows. In the center of the middle distance is the probable
antecedent canon cut through the metamorphies of the main or south ridge of the El Paso Range.

1912] Baker: Western El Paso Range 51745)

with the upper surface of the basalt. Gilbert’s original inter-
pretation of two interbedded basalt flows, as shown in his ecross-
section,® is the correct one.

These basalts are quite vesicular, the vesicles being partially
or entirely filled with quartz, chaleedony, or natrolite. Three or
four miles to the east of Red Rock Cafion the basalt flows, which
have gradually become thinner, entirely disappear.

Above the upper basalt flow in the Red Rock Canon locality
are found in upward succession: (1) a light bluish gray arkose
of coarse granite and lava breccia, interbedded with fine, green,
velvety tuff; (2) about 40 feet of rather fine, well-cemented
breccia; (3) 50 to 75 feet of ashy tuffaceous beds, quite coarse
and poorly assorted; (4) light brownish tuffs capped by two
layers of darker, reddish-brown, more resistant, fine breccia, com-
posed of the usual angular arkosic material and forming vertical
cliffs some of which are 50 feet in height.

In Last Chance Gulch the basal beds are suceeeded at 150
to 250 feet above their base by a red breccia containing dark
brick-red lava fragments in a matrix of dark pink tuff. The lava
fragments are mostly rather small, varying up to two inches or
more in diameter. They contain moderately abundant small
phenocrysts of fairly fresh oligoclase feldspar and a few pheno-
erysts of what was probably hornblende now altered to an aggre-
gate of iron oxides and chlorite. Some of the feldspar is altered
to kaolin. Magnetite is found in small grains. The feldspar of
the matrix is also oligoclase. The fragments have the same com-
position as their matrix and the rock is an andesitie tuff-breccia.

The andesite tuff-breccia is overlain by 100 feet of fine, whitish
tuff-breecia containing small angular fragments of plutonic and
voleanic rocks and pieces of white fibrous pumice. The pumice
is quite abundant at this locality. Above come bluish-gray tuffs
similar to those already described in the Red Rock Cafion section.

The highest beds of the Rosamond which were examined are
exposed about four’ miles north of Ricardo post-office. These
higher beds are in general finer and not so well indurated as
those lower down in the sertes. In contrast with the badland

6 Geog. and Geol. Expl. and Surv. west of the Hundredth Meridian, vol.
3, p. 142, 1875.

126 University of California Publications in Geology [Vou.7

topography characteristic of the lower beds the upper member
forms low hummocky mounds rising here and there above the
mantle of alluvial debris. .At the locality four miles north of
Ricardo post-office fine buff beds are capped by a dark resistant
layer of subangular to angular bowlders, some of which are as
large as a foot and a half in diameter, of very vesicular basalt,
red porphyritic lava, red lava showing flow structure, chert,
finely-laminated slate, and quartz. This capping is very local
in extent and is probably a stream deposit.

Fossils are probably to be found throughout the entire thick-
ness of the Rosamond series. They have been reported from the
basal beds in the placer diggings in Bonanza Gulch about one-half
mile east of the lower narrows of Red Rock Cafion, but no fossils
were collected from the basal beds by the writer or his associates.
Mr. George E. Stone found the skull and tusks of a mastodon
in place about 400 feet stratigraphically below the lower basalt
flow in Iron Canon, the main gulch tributary to Red Rock Cafion
on the east, about two and one-half miles east of Red Rock
Canon. The mastodon remains are in rather fine greenish-gray
tuff interbedded with coarser conglomerate layers about 200 feet
stratigraphically below the massive pink tuff-breccia of the Red
Rock Canon section. This is the lowest definitely known fos-
siliferous horizon. Fossils were found in the very topmost beds
exposed, but are apparently most abundant in the 300 or 400 feet
of beds lying next above the upper basalt flow. The fossil
remains are fragmentary and were often checked and broken
before burial. The fossil forms found include horses, camels,
merycodonts, mastodons, canids, and felids. They probably place
the age of the Rosamond series as not older than the Upper
Miocene. The definite assignment of age to the fauna cannot be
made until it has been studied in detail.

THE BLACK MOUNTAIN BASALT FLOW

The even surface of bevelled Rosamond strata is overlain on
the summit of Black Mountain by a. flow of olivine basalt. The
basalt is both vesicular and compact in habit. The flow is a
thin one, probably less than 100 feet in thickness at a maximum,

UNIV. CALIF, PUBL. BULL. DEPT. GEOL. [BAKER] VOL. 7, PL 10

Fig. 1.—General view of the outcrop of the Rosamond on the north flank of the El Paso
Range. In the foreground is the metamorphie series and intrusive diorite-porphyry overlain
unconformably by basal Rosamond. The dark capping of the hogback in the middle dis-
tance is the lower interbedded basalt flow. Farther back is the debris slope of Sierra
alluvium, with the peaks of the Sierra on the horizon. Characteristie strike valleys,
excavated in the Rosamond, are seen in the middle distance.

Fig. 2—Recent dissection of the alluvium and underlying Rosamond, three-fourths mile
northwest of Ricardo post-office. The even surface of the alluvial mantle and the northwest-
ward dip of the Rosamond strata are to be noted. This is one of the best of the fossil localities.

1912 | Baker: Western El Paso Range 127

and slopes in all directions from the summit of the mountain in
a domical structure. It forms northwardly sloping mesas on the
north flank of the mountain and southwardly sloping mesas on
the south flank. These mesas have been cut into by deep and
narrow V-shaped gullies. Just southwest of the highest peak of
Black Mountain is a depression in the basalt some thirty or forty
feet deep and approximately three hundred feet in diameter,
which may represent the crater from which the basalt was poured
out. Both Fairbanks and Hess have expressed the opinion that
the basalt had a local origin in Black Mountain, and the present
writer’s observations would induce him to regard it as only a
local flow. The surface slope of the basalt on the northwest side
of the mountain has its even contour interrupted by long narrow
ridges with their steeper slopes on the downhill side. These may
be pressure ridges. Hyalite was present with other and more
common minerals of the amygdules.

Mr. John R. Suman gives the following petrographic desecrip-

tion of this olivine basalt:

This lava under the microscope is seen to be remarkably fresh and
well preserved. It bas the intersertal structure characteristic of basic
igneous rocks.

A feldspar twinned on the albite law and developed in long ree-
tangular idiomorphie crystals makes up by far the greater part of the
rock. This feldspar has a high refraction, a positive sign, and a
maximum extinction angle on the trace of the twinning plane of about
35° showing that it is rather basie labradorite. In one instance twinning
on the Baveno law was observed. A suggestion of the glomero-porphyr-
itic structure of Judd was seen in the development in one place of quite
an aggregation of feldspar crystals in a granular mass. The feldspars
were spotted with a black opaque mineral that may have been either
magnetite or ilmenite, but owing to its indeterminate nature it will be
referred to as ‘‘opazite.’’

Surrounding the feldspar laths and filling in the interstitial spaces
were irregular grains of augite with high refraction, high bi-refringence,
positive sign, and appearing light green in ordinary plane polarized
light. This enclosed the labradorite, in many cases giving the typical
diabasie structure.

Olivine in rounded grains was also abundant in this rock and could
be distinguished by its yellowish-brown color in ordinary light, high
refraction and double refraction, irregular conchoidal fracture, large
optic axial angle when viewed in convergent light, and positive sign.
It was found included in both the augite and labradorite and evidently
was one of the first minerals to form. It showed a slight alteration in

128 University of California Publications in Geology (Vou.7

the production in many of the erystals of a reddish-brown margin called
by Weinschenk ‘‘hyalosiderite.’’ This covered the entire crystals in
some Cases.

Magnetite, in small patches, was also observed.

This rock, before referred to as an andesite,’ is without doubt
a basalt, and the term ‘‘olivine basalt’’ seems to apply best.

The topography of the basalt-covered portion of Black Moun-
tain is still well within the youthful stage, for much of the
original surface of the basalt remains undissected. Canon-cut-
ting has exposed the underlying Rosamond, the upper surface of
which has been burned red by the basalt, so that it 1s possible
by means of these red streaks to trace the original essentially
even surface of the Rosamond at the time of the lava outflow.

ALLUVIUM

Alluvium is found mainly as terraces along the drainage
courses and as a mantle of the strata of the Rosamond. It is
locally partially consolidated and much eroded.

In the east bluff at the mouth of Red Rock Canon the alluvium
is dissected to a depth of forty or fifty feet. It comprises a
heterogeneous mixture of fragments, mainly angular in contour,
of all the rocks of the Red Rock drainage basin capped by a
more resistant layer cemented by calcium carbonate. Bedding
planes are not sharply marked, but their attitude is essentially
horizontal. Some isolated patches of alluvium have been left in
the form of terraces on the walls of the cafon of Last Chance
Gulch above the present drainage channel. Horizontally strati-
fied alluvium, consisting of re-deposited materials of the Rosa-
mond, is exposed with a thickness of from ten to twenty-five feet
along a drainage channel cutting through the basalt flows about
one-half mile east of Ricardo post-office. Unconsolidated water-
worn gravels and bowlders are present in the eastern tributaries
of the lower Red Rock Canon, where they mantle the ridge facets
at the lower ends of divides between the lesser tributaries. These
were probably derived from the basal strata of the Rosamond.

The great development of alluvium is found in the debris
slopes of the Sierra, which cover the underlying rocks as far

7 By H. W. Fairbanks.

“—

1912] Baker: Western El Paso Range 129

south as the north foot of the El Paso Range. The alluvial
material is indistinguishable in texture, structure, and composi-
tion from the granite arkoses of the Rosamond series, and at
places at the foot of the north flank of the El Paso Range it is
difficult to distinguish alluvium from Rosamond. It is the prob-
lem of distinguishing residual soil or mantle rock from trans-
ported alluvium of the same nature in a region where both are
present. The alluvium has been dissected by the shallow valleys
of the upper tributaries of Red Rock Cafion and Last Chance
Gulch, and where the contact between it and the underlying
Rosamond is exposed by such dissection it is seen that the
alluvium mantles an even surface bevelling the edges of the
upturned Rosamond.

STRUCTURE

The main exposures of the Rosamond series are in the north-
ern more gentle flank of the El Paso Range. The strata dip
northwestward at an average angle of 15 degrees. The strike,
which is approximately N 25° E in the middle portion of the
exposure, curves in a southward direction near the west end
of the range. On the south flank of the range were noted two
small exposures of the Rosamond series, one on the east wall of
Red Rock Canon near its mouth and the other in the low-lying
area Just north of Kane ‘‘dry lake,’’ some eight or ten miles east
of Red Rock Canon. These two isolated exposures have the same
general dip and strike as the main exposures on the north flank.

The lower Rosamond (the strata below the basalt flows) is
eut by several normal strike faults with displacements up to
fifty feet in amount.

The south flank has a much steeper profile than the north
flank. The base of the south front of the range is a nearly
straight line and there are no shoulders projecting out from the
main mountain mass into the basin area. The stream courses of
the south flank are steep and narrow and, with the exception
of Red Rock Canon and Last Chance Gulch, exhibit lack of
topographic conformity with the wide broad basin of Kane ‘‘dry
lake’’ (pl. 8, fig. 1). From physiographic evidence alone one
would come to the conclusion that the Kane Lake basin was a

130 University of California Publications in Geology (Vou.7

structural depression and that the south front of the El Paso
Range owes its main characteristics to deformation rather than to
differential erosion. The elevation of the El Paso Range might
conceivably have been produced either by warping or by faulting
or by a combination of these two. We have already concluded
that there has been tilting of the more gently sloping north flank,
where there is only a minor amount of faulting, none of which
exhibits itself in the topography. It is next necessary to deter-
mine whether the deformation along the range’s south flank has
been accomplished by tilting or by faulting. P

In two localities along the south flank, separated from each
other by some eight or ten miles, the Rosamond is found dipping
to the northwestward, while between these two isolated exposures
and the Rosamond of the north flank les the more elevated
portion of the range composed entirely of the older rocks. This
fact in itself would suggest the presence of a fault along the
south base. If we follow the two basalt flows in the Rosamond
series from Red Rock Canon southwestward we find that their
strike swings more and more to the south until we suddenly come
upon the straight escarpment of the range’s southern front,
where both flows, together with the underlying sediments,
abruptly come to an end. We also find in the east wall of Red
Rock Canon just above the canon’s mouth, on the south flank,
that the northward dipping Rosamond, traced along the bedding-
planes, suddenly comes to an end against the metamorphies with
a fault between the two. We therefore conclude that the south
flank of the El Paso Range is a fault scarp and that the range
is a tilted orographie block bounded on the south side by a
‘*‘block’’ fault. .

The deformation which formed the existing El Paso Range
was lhmited to a narrow area between the outcrop of the inter-
bedded basalt flows of the Rosamond and the south base of the
range. Along the course of Red Rock Canon this strip is no
more than three miles in width, extending only from Ricardo
post-office to the mouth of the canon. Westward from Red Rock
Canon the zone gradually becomes more and more narrow and
the range summits lower and lower until the range finally comes
to an end about two miles west of the canon. Viewed along the

1912] Baker: Western El Paso Range 131

major axis the western portion of the range plunges westward
like an anticlinal fold.

The zone of northward tilting is limited to the region south
of the outcrop of the basalt flows because north of the flows the
bevelled surface of the tilted Rosamond beds is mantled by the
alluvial debris derived from the bedrock of the Sierra Nevada.
The surface of this alluvial debris slopes downward and south-
ward close to the base of the outerop of the basalt flows (pl. 9,
fig. 1). We are accordingly able to distinguish two separate
epochs of tilting of the Rosamond, separated the earlier from the
later by a period of erosion long enough to develop a peneplain
of at least local extent.

It is not certain whether the basalt flow of Black Mountain
has been deformed since its outpouring or whether the original
slopes of the surface over which it outflowed are preserved with
the attitudes which they had at the time of the lava outflow.
But the smooth even slope of bevelled Rosamond, covered by the
basalt of domical form, without any traces of the presence of
valleys at the time of the basalt eruption implies either that the
uplift of the El Paso Range came so soon before the basalt out-
flow that there was little time between these two events for
erosion of the surfaces of the newly uplifted range, or else that
the deformation which produced the range has been subsequent
to the basalt eruption. It is the opinion of the writer, based
partly upon his view of the antecedeney of the canons crossing
the entire uplift, that the considerable erosion of the range was
necessarily contemporaneous with its uplift, and that therefore
the deformation was later than the eruption of basalt and caused
the warping of the basalt sheet. This view is in harmony with
the previously presented conclusions of the writer as to warping
and faulting of the late basalt flows in other portions of the
Mohave Desert.

There possibly is a fault near the south base of Black Moun-
tain between the northern or Black Mountain range and the
southern or granite range. The southward-dipping surfaces of
the lava mesas on the south side of Black Mountain dip into the
northern flank of the granite range making a very appreciable
notch in the cross-section of the range as a whole. Unfortunately,

132 University of California Publications in Geology |Vou.7

the structure was not examined in that locality. If this sug-
gested fault is not present this notch must be due to erosion
which would probably have taken place between the time of the
uplift and the outpouring of the Black Mountain basalt. The
fact that the basalt flowed upon an essentially even surface is
not favorable to the latter hypothesis.

The western part of the northern or subsidiary range has
been much reduced by erosion folowing the great orogenic uplift,
whereas the eastern portion owes a part of its greater height and
a form more nearly approaching the original contour of the range,
unaffected by erosion, to the protective covering of basalt which
has greatly inhibited erosion. But there has nevertheless been a
greater amount of uplift in the vicinity of Black Mountain
than farther west, as indicated by the superior height of the
granite ridge south of Black Mountain, which height gradually
becomes less to the westward.

HIstTortIcaAL GEOLOGY

GEOLOGIC HISTORY OF THE CONSOLIDATED ROCK MEMBERS

The rocks, which are probably the oldest in the El Paso Range,
were originally sedimentary sandstones and quartz-conglomerates.
These rocks have undergone great metamorphism, probably of
the dynamo-regional type, which has obscured or destroyed the
original structure of the sediments and caused a recrystallization
of their constituents. The original conglomerate with its matrix
of sand grains and its oval or round pebbles of milky quartz has
now become a hard quartzite-conglomerate, which breaks quite as
often across the original pebbles as through the matrix or between
the matrix and the pebbles. The finer textured sandstones have
been changed to hard dense quartzite, and in some cases have
developed slaty or schistose structures.

Intruded into the metamorphic series is a diorite-porphyry,
which probably consolidated at a considerable depth below the
then-existing surface, and which, like the metamorphics, has been
altered by hydrometamorphism with the formation of the sec-
ondary minerals chlorite, epidote, calcite, muscovite, quartz, and

1912] Baker: Western El Paso Range lor}

pyrite. Intruding the metamorphics is also a dike rock, probably
a quartz porphyry, which has also suffered considerable altera-
tion. The relations of the granite with the other rocks of the
basement complex was not ascertained. But it is coarse-grained
in texture and is evidently a plutonic rock which consolidated
deep beneath the surface and has since been exposed by erosion
of great amount. The granite, after its partial or entire con-
solidation, was intruded by pegmatite and aplite dikes.

The only definite clue to the age of the rocks of the basement
complex is furnished by the unconformably overlying and hence
younger Rosamond series which is not older than Upper Miocene.
There was great erosion after the deposition, metamorphism, and
intrusion of the rocks of the basement complex before the time
of deposition of the overlying Rosamond series, for the deep-
seated rocks of the basement complex were laid bare at the sur-
face and covered by the Rosamond sediments laid down on the
surface of the land. Therefore the rocks of the basement complex
must be of considerably greater age than the Rosamond series.

The materials of the Rosamond have been derived from three
sources: (1) by erosion from the rocks of the basement complex ;
(2) by erosion from lava flows later in age than the rocks of
the basement complex; (3) from pyroclastic materials, compris-
ing ash and pumice, blown out from voleanoes and deposited
either by wind action, by the agency of water, or by settling
during and after volcanic eruptions. The agencies of deposition
were of the continental or terrestrial type and are believed to
have been the same as those forming the desert alluvial deposits
being laid down at the present day. All the fossils found in the
Rosamond series in the El Paso Range represent the remains of
terrestrial mammals and tortoises. There is little or no evidence
of lacustrine sedimentation in the lower half of the Rosamond of
the El Paso Range, and the finer sediments of the upper strata
may well be eolian deposits or deposited by any or all of the
subaerial processes with their materials derived from the erosion
of low-lying areas. Contemporaneous with the deposition of the
middle portion of the Rosamond were two outflows of basaltic
lava.

134 University of California Publications in.Geology [Vou.7

GEOLOGIC HISTORY POSTERIOR TO THE TIME OF DEPOSITION OF THE
ROSAMOND SERIES AS INFERRED FROM THE STRUCTURE

AND PHYSIOGRAPHY

The Two Epochs of Post-Miocene Uplift with the Intervening
First Cycle of Post-Miocene Erosion.—The Rosamond series both
on the north and south flanks of the El Paso mountains was
tilted to the northward at a moderate angle after its deposition.
It was then subjected to long erosion which bevelled off the tilted
beds to an essentially level surface. The peneplain formed by
this eyele of erosion is correlated with the one developed on the
folded Rosamond beds in the vicinity of Barstow, in San Ber-
nardino County. At the end of the first cycle of post-Miocene
erosion or more likely after renewed deformation had caused a
new cycle to begin a thin veneer of alluvial debris was spread
over the bevelled surface of the Rosamond strata northeast,
north, and northwest of Ricardo post-office. This alluvium was
derived from the erosion of the recently uplifted Sierra Nevada
Range. Because of the coarseness of the arkosic material of the
alluvial mantle and the almost total absence from it of the
products of mature chemical decomposition, and because an
erosion surface similar to that produced by the first cycle of
post-Miocene erosion in the El Paso Range was also developed in
the Sierra Nevada it is thought most probable that the deposition
of the alluvium mantle on the evenly eroded surface of the Rosa-
mond was brought about by a mountain-making uplift in the
southern Sierra Nevada. An uplift, to which the present El Paso
Range owes its existence, followed the development of the pene-
plain and caused the development of a great fault along the
southern base of the range at the same time that an uptilting
took place on the northern flank. But probably before this
uplift occurred the basalt flow of Black Mountain was erupted,
covering the substantially flat and even erosion surface developed
on the uptilted Rosamond series.

Origin of Red Rock Canon and Last Chance Gulch.—These
drainage channels cross the main southern ridge of the El Paso
Range in deep, narrow, and precipitous “cafions although in
their upper reaches they have developed broader, shallower, and

1912] Baker: Western El Paso Range 135

subsequent courses in a region of lower altitude and less resistant
rocks. The lower narrows cannot be consequent to the original
slope formed by the uplift. They cannot be superimposed
because the El Paso Range and the adjoining Kane basin are
structural features which do not owe their larger orographic
features to erosion. Hence they must be either antecedent in
their origin or have cut back through the range by headward
erosion and captured and diverted drainages more nearly con-
sequent to the uphft.

There are several facts against the view of the development
of these lower cafions by headward erosion. All the other drain-
age courses on the south side of the range are small and have
eut back but a short distance into the mountain ridge. Their
valleys have steep gradients out of topographic adjustment with
the Kane basin to which they are tributary, but the valleys of
Red Rock Cafion and Last Chance Gulch are in topographic
adjustment with the basin. Red Rock Canon and Last Chance
Gulch have valleys which are no older in their lower courses just
inside the southern searp than where they first enter the more
resistant rocks farther up. No evidence of the former existence
of a consequent drainage down the northern flank of the range
and around its western end into the Kane basin or eastward into
the Salt Wells Valley was found, although these regions were
not fully examined in the field. It is apparently hard to account
for the devious windings of the narrow but deeply incised Last
Chance Gulch, cut in aparently homogeneous granite, if its course
was developed by headward erosion, but these meanders may
very well have been inherited from a previous cycle. Also the
drainage channels of the north flank, developed along the strike
of the Rosamond strata, do not follow the foot of the range, but
have become subsequent. They have shifted their courses until
the broadest, largest, and deepest of them have come to occupy
the contact between the Rosamond series and the more resistant
basement complex in the manner first explained by Gilbert in
his account of the geology of the Henry Mountains of Utah.
The fairly well adjusted drainage of the north flank is in marked
contrast with the canons cutting through the range. Finally,
no evidence is known of lower gaps in the profile of the range’s

136 University of California Publications in Geology [Vou.7

longer axis, produced by a greater amount of differential uplift
on both sides of the localities of Red Rock Cafion and Last Chance
Gulch, which might have given sites to courses of consequent
drainage. The evidence thus points strongly to an antecedent
origin for the lower courses of Red Rock Cafion and Last Chance
Gulch.

Among the most remarkable features noted by the writer in
the southern Great Basin must be included those probable ante-
cedent drainage courses which have been developed athwart the
courses of the lately uplifted ranges in a region where the present
rainfall is so scanty. Even if one assumes that precipitation was
greater in former times than now, these antecedent drainage
courses bear an eloquent testimony to the slowness of the moun-
tain uplifts. And yet these mountains have probably been up-
lifted since the close of the Tertiary.

Recent Faulting.—Hess* has recently described rift features
caused by the faulting along the southern base of the eastern
El Paso Range north of Garlock station, where these features are
so striking as to have been noted by the present author from the
railway train. There are some suggestions of recent faulting
along the south base of the range between the mouths of Red
Rock Cafion and Last Chance Gulch, in the nature of truncated
shoulders separated by shallow depressions from low hummocks
with their courses parallel to the range’s south base. One of
these low hummocks can be seen at the base of the escarpment
in the middle distance in plate 8, figure 1. It is quite possible
that there has been a small uplift of the range recently, which has
been responsible for the recent trenching of the alluvium at the
mouths of Red Rock Cafon and Last Chance Gulch and for the
formation of the alluvial terraces higher up in these drainage
basins. This view must be regarded as a mere suggestion, how-
ever, which is worthy of more extensive investigation.

8 Gold mining in the Randsburg Quadrangle, California, U. S. Geol. Surv.,
Bull. no. 430, pp. 23-47, 1910.

1912] Baker: Western El Paso Range ENT

THE SOUTHERN SIERRA NEVADA

The south front of the Sierra Nevada from Jawbone Canon
northeastward to Indian Wells is in a stage of physiographic
development older than that found in the range to the east and
west. This is due to a deformational history of this section of
the Sierra flank different from that of the greater part of the
range to the east and west.

Tue Ricarpo Erosion SURFACE

From the summits above Walker Pass one looks out to the
east, north, and west over broad-topped summit mountains.
These broad summits have a gently rolling topography mani-
festly the product of an older erosion cycle than that which
formed the valleys which have isolated these peaks one from the
other. This old erosion surface is apparently, although not
certainly, the same as that of the Chagoopa Plateau described
by Lawson in the Upper Kern Basin.? What relation does this
old erosion surface bear to the peneplain of the Mohave Desert?
In order to determine this relation let us consider the region
lying between the crests of the Sierra and the peneplain developed
on the Rosamond series north of the El Paso Range.

Above the piedmont alluvial aprons the peaks of the southern
Sierra rise rather abruptly. The lower slopes are rounded, while
back towards the summits the declivities are rugged and abrupt.
Long narrow shoulders run out into the desert with gradually
diminishing height. Between these shoulders are broad re-
entrants occupied by broad, mature, rather low grade, and open
valleys, in topographic conformity with the lower debris slopes,
and reaching far back into the range. It becomes at once evident
that we have here a topography which has already gotten beyond
the most rugged stage of maturity and is near early old age in
its development. This advanced stage of topography is only
found along the southern slopes; for in rising to the heads of

9 The Geomorphogeny of the Upper Kern River Basin, Univ. Calif. Publ.
Bull. Dept. Geol., vol. 3, pp. 291-376, 1904.

138 University of California Publications in Geology (Vou.7

these drainage channels one finds oneself on a summit upland
which is noticeably broad in places and can be traced to the
north, east, and west in neighboring summits. The presence
of considerable remains of the summit upland between the valleys
indicates that this higher portion of the range has only reached
the stage of early maturity, since the whole surface is by no
means entirely reduced to slopes. We see, therefore, that since
the time of formation of the old erosion surface the surface of
the summit upland of the Sierra has been uplifted and a new
cycle of erosion begun which has reached the stage of late
maturity or early old age in the outer slopes of the range and
a stage of early maturity near the heads of the drainage courses
in the summits.

It was during this last eyele that the debris apron was spread
out beyond the foot of the range by deposition of the materials
removed by erosion from the mountains’ southern slopes. The
erosion folowing the last uplift has dissected the old surface of
the Sierra summits and the alluvium derived from this erosion
has covered the surface of the peneplain developed on the tilted
Rosamond series. So we can conclude that the post-Miocene
peneplain of the Mohave Desert region has its contemporaneous
counterpart in the old erosion surface of the summit uplands of
the Sierra, tentatively correlated with the Chagoopa Plateau
surface of the Upper Kern Basin. And since it has become neces-
sary, in deciphering the later Cenozoic history of the Great Basin,
to refer to these erosion cycles as datum planes in much the same
way as rock formations are used, the writer proposes the name
‘*Ricardo erosion surface’’ for the product of this post-Miocene
eyele of erosion, which antedated the great deformation of the
southern Sierra Nevada that has given to the range the altitude
and major orographie features which we see in it to-day.

The Ricardo erosion surface where it is developed on the less
resistant Rosamond series, and, for that matter, on some of the
granitic bedrock surfaces, of the Mohave Desert is an unques-
tionable peneplain. North of Walker Pass in the southern Sierra,
disregarding the effects of tilting, of possible faulting, and of
later erosion, it has a maximum differential relief of a thousand
feet or more and is an erosion surface in approximately the

1912 | Baker: Western El Paso Range 139

middle of the old age stage. As one goes northward the surface
rises steadily in altitude until west of Mount Whitney it is on
the average 11,000 feet above the sea, whereas in the vicinity of
Walker Pass it has an average altitude of from 6,500 to 7,000
feet. In the Mount Whitney region the peaks of the Great
Western Divide and the main Sierra crest rise 2,000 feet and
more above its general surface, the highest peak of all, Mount
Whitney, rising some 3,500 feet above it. Here the stage of
erosion reached at the culmination of the cycle was not developed
further than early old age. We have good reasons, therefore,
for concluding that at the end of the Ricardo post-Miocene cycle
of erosion there still existed a residual mountain range on the
site of the highest crests of the present Sierra Nevada.

Latest Eprocu oF FAuLTING, NoT AFFECTING THE ENTIRE

SOUTHERN SIERRA FRONT

If one examines the stage of topography of the east flank of
the Sierra west and south of Owens Lake, as represented on the
Olancha topographic sheet of the United States Geological Sur-
vey, and compares it with the stage of topography of the east
flank south of Walker Pass on the Kernville topographic sheet,
one notes a remarkable difference. The eastern scarp of the
Sierra in the neighborhood of Owens Lake is very precipitous,
the base of the range approximates a straight line with no broad
re-entrants along the drainage courses, or shoulders projecting
out into the basin area between the drainage courses. All the
canons cutting into the east front of the range have deep, narrow,
steep-walled, and V-shaped courses. The topography of the east
front of the Sierra from Indian Wells northward into and
beyond Owens Valley is much more youthful than that of the
section of the range from Indian Wells southwestward to Jaw-
bone Canon.

Looking into the Sierra from one of the lower summits in
the vicinity of Jawbone Canon one sees near the horizon line
a broad shallow, high-level valley corresponding in stage of
development with those opening out on the foot of the range
farther east. But as this drainage course is traced down

140 University of California Publications in Geology [Vou 7

towards the desert one notes that it becomes incised in a deep
and narrow canon which is totally unlike anything developed
along the lower courses of the drainage to the eastward.
Recent rejuvenation has evidently taken place in the valleys
of the Jawbone Canon drainage. At the foot of one of
these lower summits there is a rather deep valley coming out of
the Sierra into the Mohave Desert. The lower course of this
valley is a box canon which comes to an abrupt head at the place
where the Los Angeles aqueduct crosses it. In the eastern wall
of this canon is exposed northwestwardly-dipping Rosamond
greenish tuff-breecia, overlain unconformably by unconsolidated
alluvium of light reddish-brown color and derived from the
granitic bedrock of the Sierra. In the opposite canon wall is
exposed the granite. Between the granite and the Rosamond is a
fault along which recent displacement has taken place. The
plane of the fault has been followed by the canon. The fault
traces approximately north and south, swinging to the westward
farther south, and its plane dips from fifty to sixty degrees to
the east. The cutting of the box canon has been accomplished
since the deposition of the unconsohdated debris forming its
upper walls. The topographic expression of the fault is marked
by an abrupt break in the profile. The granite rises above the
general level as abrupt hills and mountains while the lower-lying
Rosamond directly up to the fault contact is eroded into a much
gulhed topography. This zone of recent deformation continues
westward to Tehachapi and Cajon passes.

Between Indian Wells on the east and Jawbone Cajon on the
west there is no evidence of recent faulting such as appears in
the region west of Jawbone Canon. Between Indian Wells and
Jawbone Canon there is a section of the southeastern front of
the southern Sierra Nevada exhibiting older topography than
the regions of the front to the northeast and to the west which
have undergone more recent uplift.'°

10 For a description of the older topography of this section see the
second paragraph under the heading of the Ricardo Erosion Surface.

1912 | Baker: Western El Paso Range 141

DISSECTION OF THE SIERRA DEBRIS SLOPES

The distance from the exposures of bedrock on the southern
slopes of the Sierra to the base of the north flank of the El Paso
Range in the vicinity of Red Rock Canon and Ricardo post-office
is probably not greater than four or five miles. In the entire
interval between the ranges the alluvial surface slopes down-
ward to the south at an angle which averages about two degrees.
There can be absolutely no doubt that the debris of this slope to
within a mile to the north of Ricardo post-office has been derived
from the Sierra, for in its finer parts it is composed of dis-
integrated crystals of the Sierra granite and the larger angular
bowlders are fragments of this same granite. The alluvium has
a characteristic light brown color given it by the feldspars of
the Sierra granite. The alluvium, apparently originally spread
out rather evenly and in quite uniform thickness over the pene-
planed surface of the Rosamond series, has been dissected by
shallow gullies and valleys. Just north of the foot of the El
Paso uplift a rather broad basin has been excavated in this
alluvial mantle and the underlying Rosamond strata (pl. 9, fig. 1,
and pl. 10, fig. 2). Further north the debris mantle and the
lying Rosamond have been rather intricately dissected into a low
hummocky topography. Still farther to the north, near the
lower bedrock slopes of the Sierra, a much greater proportion
of the original debris-mantled upland surface remains, incised
at rather wide distances to only moderate depths by the main
drainage courses leading down from the Sierra Nevada, and
between these main drainage courses by smaller and shallower
gullies. In brief, the impression given the observer stationed on
the lower bedrock slopes of the Sierra is of a plane sloping rather
gently to the southward, the general smooth surface of which is
cut here and there by shallow gullies and valleys.

A general uptilting to the northward of the surface of the
debris aprons or a depression of the Kane basin relative to the
country farther north would cause dissection of slopes formerly
at grade. Any change of climate which would increase erosive
forces could cause the dissection of this alluvium. Or it might
normally become dissected, without the interposition of uplift

142 =: University of California Publications in Geology [VoL 7

or change of climate, a possible explanation which has been
more fully considered by the writer in an earlier paper.** The
depression between the Sierra Nevada and the El Paso Mountains
may have been a higher temporary base level, since drained by
valleys tributary to the lower base level of the Kane basin, in
which case the courses of Red Rock Cafion and Last Chance
Gulch would not be antecedent but have developed their canons
across the El Paso Range by headward erosion. But a piedmont
alluvial fan spread out during or soon after the uplift of the
Sierra, when slopes were steep and debris abundant, would sub-
sequently be dissected when the supply of debris became less,
allowing running water to erode in places which were formerly
the sites of aggradation.

SUMMARY .

1. The oldest known rocks of the El Paso Range are a series
of metamorphies cut by intrusives.

2. Unconformably overlying the basement complex is the
Rosamond series of fossiliferous sedimentary rocks of an age
probably not older than the Upper Miocene.

3. The Rosamond series was tilted at a moderate angle and its
strata bevelled by peneplanation. This peneplain is named the
Ricardo erosion surface and is tentatively correlated with the
Chagoopa plateau of the Upper Kern Basin.

4. Following peneplanation came an eruption of olivine basalt
and the uplift of the present El Paso Range. The range has the
form of a faulted monocline with its south flank a fault searp.
Two drainage courses crossing the entire range are believed to
have been antecedent to the uplift.

5. The south front of the Sierra Nevada directly north of
the El Paso Range has not been affected by an uplift which
affected the rest of the southern Sierra to the east and west.

6. The piedmont alluvial slope of that portion of the Sierra
Nevada situated north of the El Paso Range is at present under-
going dissection.

"11 Notes on the later Cenozoic history of the Mohave Desert region in

southeastern California, Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, pp. 374—
377, 1911.

Issued December 4, 1912

E/ FROM THE TYPE LOCALITY OF
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“BRUCE MARTIN

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DEC 17 1912

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3. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by
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4, Triassic Ichthyopterygia from California and Nevada, by John C. Merriam.
6, The Igneous Rocks near Pajaro, by John A. “Reid... ic. o2..c.fc-2-cncteencencoeesanceeen eden
7. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller 1
8. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by
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15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson.............. :
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17. The Orbicular Gabbro at Dehesa, San Diego County, Caiifornia, by Andrew CO.
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18, A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. ;
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmon
20. Euceratherium, a New Ungulate from the Quaternary Caves of California, by
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21, A New Marine Reptile from the Triassic of California, by John C. Merriam -......
22. The Riwer Terraces of the Orleans Basin, California, by Oscar H. Hershey... %

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CG; Merriam a ec ee ge OM as ce a a eee
Geological Section of the Coast Ranges North of the Bay of San Francisco, by

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Arcas of the California Neocene, by Vance C. Osmont.............-...
Contribution to the Palaeontology of the Martinez Group, by Charles E, W
New or Imperfectly Known Rodents and Ungulates from the John Day ie

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 7, pp. 143-150 Issued December 4, 1912

FAUNA FROM THE TYPE LOCALITY OF

THE MONTEREY SERIES IN
CALIFORNIA

BRUCE MARTIN

CONTENTS

PAGE

TASC RU) (0) Toe oe Ee 143
FETS GON Call SVC MMC We be Fcc ot sso ccs seasveSescceoiuetecves esta cusdoeett etch atenteseuecesseesecvivecces sie 144
Wesermption of the: Type! Locality -.....--.c.s---csccsassscceececseeeesecsteceececeeeeerececese 145
Wocatiom and Topography 2cccc.c-cececcccceceecceetececcseccence-eeneoees areas eee 145

PSI TREE ETT OVO fc eA ae ee SE PERE er SR a 145
TUpH BLN KOK 7 cea ee a a Ee eee 146
Fauna of the Type Locality ......................-- pee ee eee Ire 147
Correlation with the Monterey of Contra Costa County .........---....- 149

INTRODUCTION

In the course of a study of the Monterey series, as it appears
along the east shore of San Pablo Bay and in the vicinity of
Mt. Diablo, the writer found it necessary to compare the fauna
with that of the type section of the Monterey at the town of Mon-
terey. The writer visited the type locality and brought together
what seemed to be a representative collection of the molluscan
fauna. As comparatively little relative to the palaeontology of
the type section has been published it seemed desirable to record
such information as is available.

144 University of California Publications in Geology [Vou.7

HISTORICAL REVIEW

The first reference to the formations known as the Monterey
series in the literature of Pacific Coast geology is by Dr. W.
P. Blake? in describing a series of sedimentary rocks, mostly
diatomaceous shales, which occurs near the town of Monterey.
Dr. Blake’s observations were made during the latter part of
1854 while he was geologist for the Pacifie Railroad Survey. In
his description of the formation he refers to it as a ‘‘formation
teeming with the skeletons of microscopic organisms which
appears to overle and to be conformable to the Tertiary strata
that underlie a part of the town of Monterey and to extend to
and beyond the Mission of San Carlos.’’ The Tertiary strata
underlying the town of Monterey are a part of the formation
containing the skeletons of microscopic organisms to which refer-
ence is made by Blake. This fact was recognized by him as is
indicated in the later part of his report. His separation of the
two is probably due to his finding a few casts of foraminifers in
the lower horizons instead of the diatoms, which were found in
the upper horizon. 5

The stratigraphic relations noted by Blake were as follows:
The Monterey was seen to rest directly upon the granite of Point
Pinos and was not found to be covered by any later formation
other than Recent or terrace accumulations along the bay shore.
Blake’s description of the lithology of the beds is as full and com-
plete as can be desired. The fauna that is listed in his report is,
however, very meagre and is not particularly characteristic of any
division of the Tertiary. The species listed were: Tellina con-
gesta Conrad, a few borings of Petricola cylindracea, casts of
foraminifers, and diatoms. The diatoms were determined by
Professor Baily of West Point as belonging to the genus Coscin-
odiscus.

In 1893 Professor A. C. Lawson published an account of the
geology? of Carmelo Bay in which he distinctly defined the
Monterey series and gave a discussion of its stratigraphy and

1 Blake, W. P., Proc. Acad. Nat. Se. Philad., vol. 7, pp. 328-331, 1855.
Also Pacific Railroad Reports, vol. 5, pp. 180-182, 1855.

2 Univ. Calif. Publ. Bull. Dept. of Geol., vol. 1, pp. 1-59, 1893.

1912] Martin: Type Locality of Monterey Series in California 145

lithology. He also published a list of the fossil marine inverte-
brates upon which the determination of these beds as Miocene
was based. The following species, identified by Dr. W. H. Dall,
were noted by Professor Lawson :

Area, sp. (nov.?).

Saxidomus, sp.

Leda, sp. (nov.?).

Lueina, like L. crenulata.

Clementia?, sp.

Young Cardium or small Venericardia.

Pecten (Pseudamusium) peckhami Gabb.
Macoma, sp. (nov.?).

DESCRIPTION OF THE TYPE LOCALITY

Location and Topography.—The territory over which the ob-
servations on the typical Monterey were extended comprises an
area about four miles square between Monterey Bay and the
valley of the Carmelo River, and lying principally east of the
main coast road leading from Monterey to Carmel-by-the-Sea. A
small area occurs in the higher hills west of this road. Several
short excursions were made beyond the limits of this territory,
but they have no direct bearing upon the results. This locality
lies at the north extremity of the Santa Lucia Range, and while
it may be easily separated physiographically from the region to
the south of the Carmelo River valley, it must, nevertheless, be
considered a part of the range. The physical features show
well-rounded hills and flat-topped ridges whose flanks are dis-
sected by numerous streams and ravines. In no case does the
elevation exceed eleven hundred feet. From Point Pinos the
hills rise abruptly to the southward, attaining an elevation of
approximately eight hundred feet two miles southwest of Mon-
terey, where they swing to the eastward, forming a crescent-
shaped chain around the town.

Stratigraphy.—tThe stratigraphic relations of the Monterey
series are very simple. At several localities along its western
border it may be observed resting almost horizontally upon the
eroded surface of the Santa Lucia Granite. On the northern and
eastern boundaries the shale passes beneath the Recent or terrace
accumulations which flank the hills in the vicinity of Monterey

146 University of California Publications in Geology [Vou.7

and Carmelo bays. The western limit of the series may be
roughly followed by the outcroppings of the granite in the lower
portions of the hills and over the more nearly level territory sur-
rounding the town of Monterey. On the summit of the main
ridge, two miles southwest of Monterey, and on the south side
of this ridge, both the shale and the granite are mantled by a
considerable thickness of brown to yellow sand, which prevented
the accurate mapping of the formations. One of the most favor-
able localities for observing the relations of the shale and the
granite is seen in a small creek near the middle of the town of
Monterey. The east bank of this stream stands perpendicular for
twelve feet or more. At the base of this section the solid granite
is exposed. Coarse-grained sandstone and boulders immediately
overlie the granite. Passing upward the beds grade into finer
sandstone. Near the top of the section the sandstone is replaced
by clay shale or mudstone. Several feet back from the precipitous
banks of the stream the typical whitish-yellow bituminous shale
was found in place, approximately thirty feet stratigraphically
above the granite, showing the rapid transition from sandstone to
shale. A sheht tilting to the eastward is the only movement that
has affected the shale, excepting a few minor dislocations due to
faulting. The inclination of the strata from the horizontal is
seldom greater than fifteen degrees and frequently not over five.
In several localities immediately southeast of Monterey the beds -
were found lying approximately horizontal. A conservative esti-
mate of the thickness of the beds would place it at no less than
two thousand feet.

Lithology.—tThe character of the rocks and the theories as to
their origin have been dealt with at considerable length by Pro-
fessor Lawson in his publication to which reference has been made
above, and it does not seem necessary to do more than review
the general types of rocks that are found in this series. The
series, as exposed at the type locality, consists mainly of white
and light yellow shales, usually well bedded and very resistant to
weathering. The shale can be separated lithologically into three
types: (1) a soft chalk-like rock which appears to be largely of
diatomaceous origin; (2) a cherty shale which is very brittle
and breaks with a smooth, glassy fracture; (3) an arenaceous and
argillaceous shale. In the upper portion of the series the dia-

1912] Martin: Type Locality of Monterey Series in Califorma 147

tomaceous shale greatly predominates. In the lower portions
the cherty and arenaceous phases are quite common. Besides
these there are variations of local importance, as they are
the phases from which the greater number of the fossil marine
invertebrates were obtained. One of these localities occurs along
the Pacific Improvement Club’s driveway approximately one and
one quarter miles northeast of Carmelo Bay. Here a section is
exposed in which the strata are dipping toward the northeast at
an angle of ten or fifteen degrees. The base of the section con-
sists of yellowish-brown limestone and calcareous sandstone which
grades upward into a purple, fine-grained sandstone. <A short
distance above the fine-grained sandstone the typical bituminous
shale was encountered, conforming in strike and dip to the strata
in the lower portion of the section. As this locality occurs along
the western border of the shale area it is believed to be near the
base of the series. The limestone yielded eight species of fossil
invertebrates. Another locality of equal importance was en-
countered in the bed of a deep canon two miles due south of Mon-
terey. Here a friable, fine-grained, gray sandstone outcrops
beneath the well-stratified shale. Since this sandstone is only ¢
short distance, horizontally, from the granite it seems certain
that its stratigraphic position is not far distant from the base of
the series. Like the former locality it yielded a small collection
of marine molluscs.

FAUNA OF THE TYPE LOCALITY

As is usually the case with the shale formations, the Monterey
of the type locality contains relatively few species, though the
number of individuals may be large. Casts of small bivalves and
univalves are of common occurrence throughout the formation,
but the specific and generic characters are not determinable in
most cases. The total number of species so far reported from
the beds at Monterey does not exceed fourteen, of which six are
here reported for the first time. The following species, arranged
according to the horizons from which they were obtained, com-
prise the known molluscan fauna of the type section of the Mon-
terey. Cetacean bones, foraminifers, diatoms, and remains of
small crustaceans are also known from these beds.

148 University of California Publications in Geology {Vou.7

LOWER PorRTION

Pelecypoda.
Area obispoana Conrad.
Glycimerus, sp.
Leda, compare taphira Dall.
Modiolus, sp.
Nueula, sp.
Pecten peckhami Gabb.
Macoma congesta Conrad.
Venericardia montereyana Arnold.
Sharks teeth.

Gasteropoda. ’
Ficus kernianum Cooper.
Trochita, sp.

MIDDLE PORTION
Pelecypoda.
Area obispoana Conrad.
Marcia oregonensis Conrad.
Macoma congesta Conrad.

Upper Portion

Pelecypoda.
Marcia oregonensis Conrad.
Macoma congesta Conrad.

Gasteropoda.
Neverita, sp. indet.

Several of the species listed above are of sufficient importance
to warrant further consideration. Arca obispoana was described
by Conrad from a shale formation in the Salinas Valley in San
Luis Obispo County, California. The exact locality and horizon
are not, at present, definitely known. However, it seems most
probable that it was obtained from the shale which immediately
overhes the Vaqueros sandstone. It has also been reported from
a corresponding horizon in the Santa Cruz Quadrangle. Pecten
peckhami Gabb is most commonly found in the lower Miocene.
It has been reported from the uppermost Eocene in the Coalinga
region, but its occurrence below the lowest Miocene is exceed-
ingly rare. Middle Miocene is considered the upper limit of
its range. Venericardia montereyana Arnold was described
from the lower middle Miocene shales of the Santa Cruz Quad-
rangle; its occurrence has not been noted outside of this horizon.

1912] Martin: Type Locality of Monterey Series in Califorma 149

Marcia oregonensis Conrad has not been found below lower
Miocene in this part of the coast ranges. It is most commonly
found above middle Miocene. Ficus kernianum Cooper was first
obtained from the lower Miocene of Kern River, Kern County,
California. It is believed to be characteristic of middle and
lower Miocene. The number of species comprising the fauna of
the Monterey is very limited; some of them, however, are con-
fined to a small vertical range and serve definitely to place the
beds within middle and lower Miocene.

CORRELATION WITH THE MONTEREY MIOCENE OF
CONTRA COSTA COUNTY

Miocene strata, supposed to be of the same age as the Mon-
terey, occur along the east shore of San Pablo Bay and in the
vicinity of Mount Diablo. One of the largest and most important
of these areas extends from San Pablo Bay southeast toward the
town of Walnut Creek. The strata have been folded into a broad
synecline whose axis strikes approximately N. 50° W. Along the
northern border of the syneline, near Selby Smelter, the beds lie
unconformably upon a dark shale which is considered to be of
lower Eocene age. Along their southern boundary they rest in
part, presumably, upon the Tejon formation, of upper Eocene
age. The San Pablo beds lie upon this series. At Selby the sec-
tion is composed of brownish-gray sandstone and rusty, yellowish
shale. The strata are inclined toward the southwest at a high
angle. In a few localities they are standing almost vertical. The
thickness is between three and four thousand feet. The south
side of the syncline is composed of both sandstone and shale. The
shale in the lower portion is composed of a white, well-stratified
rock which resembles very closely the shale at Monterey. The
shale occurring in the upper part of the section is more argil-
laceous and of a rusty-yellow color. The sandstone is principally
a gray, medium-grained rock. The dip of the strata is toward
the northeast at angles varying between thirty and forty degrees.
The total thickness is very close to five thousand five hundred feet.

The correlation of the Miocene on San Pablo Bay known as
the Miocene of Contra Costa County with the type section of

150 University of California Publications in Geology [Vou 7

Monterey must depend to a large extent upon the faunal evi-
dence, since there are no similar stratigraphic relations existing
at the two localities. On the north side of Carmelo Bay there
are beds which may be of Eocene age, but no localities were
found where the Monterey shale was in contact with them.

Faunally there appears to be sufficient evidence to correlate
the beds at Monterey and the lower portion of the Miocene sec-
tion on San Pablo Bay. All of the species of marine inverte-
brates that have been reported from the type section at Mon-
terey have been obtained from the beds at San Pablo Bay with
the exception of Venericardia montereyana Arnold. Pecten peck-
hami Gabb occurs in the lowest shale at Pinole and in the lower
portion of the formation at Monterey. Marcia oregonensis Con-
rad and Ficus kernianum Cooper occur in both formations, the
former very commonly.

The results obtained in this investigation may be stated as
follows: The evidence furnished by the fauna of the type section
of the Monterey series supports the general assumption that
the deposition of the beds at the type locality was approximately
contemporaneous with that of the middle and lower portion of
the Monterey Miocene appearing on San Pablo Bay.

| IFORNIA PUBLICATIONS — :
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No. 8, pp. 151-168 Issued December 4, 1912

EISTOCENE RODENTS OF CALIFORNIA

LOUISE KELLOGG

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Vol. 7, No. 8, pp. 151-168 Issued December 4, 1912

PLEISTOCENE RODENTS OF CALIFORNIA

LOUISE KELLOGG

CONTENTS

PAGE

Tin bee UO RNA a er 152
List of Rodents arranged according to Life Zones .........-..-.--0-0-----— 154
SSO Cle smmimas © hve ple Ua Steer ceeweteetcee coarse etree See ccce nega nteee car crencceesdcivesresverazae=eres 154
Arctomys flaviventer Aud. and Bach? ..............-------:eseeeeeeeeeeeeets 154
@astortsubauragus Cay lor? ssec.ccccse.csecs--22b-0ccsenccsenedecencnsandecrsedenscentetceveneeees 155
Citellus beecheyi douglasi (Richardson) ~............2--2-------e-eeeeeeeeeee 155
Callospermophilus chrysodeirus (Merriam, C. H.) ......---.------------------ 156
PBC ATW AS STO a eee eeee eo eee c ere c ae oon baee /-eececesstecsezcetsqasvensvacecatcsstzucevaceeaueet@fen-nocze= 156
SCUUUSPOTISCUSHOSSIIUS | Me sSUOS Peet secnerseereereceecceereceneeceeeesereeeceeseeceeze-cecce 156
Sciurus douglasi albolimbatus Allen ...........-.2----------e ee 157
Seiuropterus alpinus klamathensis Merriam, C. H. -........--..---------- 157
Aplodontia major fossilis Sinclair —......-.-.-.--.-.-------ceeeeeeeeeeeeee eee 157
eromiyScuss m= GamMbelia(BSaANd!)| 2..2c-cccccccceeceeceeceseeeceseceneeecsececnseraneeseecerone= 158
Neotoma cinerea occidentalis Baird .................2...2-220220-----eeeeeete 158
Microtuscaltionnicus GReale)) <...----ccc.-c--c-ccececcecceecacaeecuesee-seccsecectsvecect=css 160
MUO TNO MY; Ss WLC O COM 1M CLAM ooo oan canz ce ance omen ce enn caw ne cee ae ee roe eee ce cece eee 160
Mhomomys: leucodon Merriam, ©. TL. ? 2.2.2 nen eennte nen ceetececceee reece ene 161
ret hizon eprxambhum Lan WG je :s2csssscseseccceeceeeeseecceseceseseenenmnaceececeenerenaseeaese 162
Me US m Call uto Tt CUlsgs MANY gree sensenes esese eer srerseecetecceceeestcaadeeescaceasereceeec-fe7a-¢=202 163
Lepus a. klamathensis (Merriam, C. H.) ............-..------:eseeeseceeeeeee 164
Siyvalley ors tec Onis (OS alti lh) case seauseteeces seta sete ectcsterenaceeeerecnzeeeneeaaesteccencnzaze 164
Se Cle smpr omMebvan Chom lan LCA sereeseenseerscsers-cteteecsececeeesneeeeeeeeesencrce-ceeeeeeneeeceoeo 164
Citellus beechey1 captus, n. SUDSD, ......:----..:-------------sccsenensessesereesacteene=s 164
IReTOMySCUSINs CAMMY (BAT yoo. cecescececccscceeneee-screnecceeesnaeaennceceene 166
Marcrotusecalitornicus) (Peale) 22¢-2.cccccec-caceovacsecncctccssececuensonnceccseeceneneeneesee 166
Thomomys bottae pallescens Rhoads ..............-...--.--:::s:c--sceeeeeeeeeeeeeeeeees 167
ero dnpusnagalas (Grab el))! see. 22. sacees-ece-ecaseceeceocenseceecetececeaceceeee-eectcescsceeos 167
Sylvilagcusaudubont (Bard) 2ec.cs-- ee cccc cere -cnseeeenseeseeeee- ... 167
Sylvilagus bachmani cinerascens (Allen) 168

152 University of California Publications in Geology [Vou.7

INTRODUCTION

The Pleistocene rodents described in the following paper were
obtained from Potter Creek Cave and Samwel Cave on the
McCloud River, Shasta County, California, and from the asphalt
deposits at Rancho La Brea, near Los Angeles, California. The
specimens are all from the palaeontological collections of the
University of California.

Potter Creek Cave has already been fully described and a list
of the species found in it given by W. J. Sinelair;? a brief
description of Samwel Cave is furnished by E. L. Furlong ;?
while a discussion of the Rancho La Brea beds has been pub-
lished by J. C. Merriam,’ so that any detailed description of the
three localities seems unnecessary. The caves were formed along
fissures mainly by percolating water removing lmestone in solu-
tion and not by the action of streams. The rodent remains of the
caves are found in strata of clay with gravel lenses, excavated
down to a depth of twenty-five feet, and they are very abund-
ant in places, especially those of Neotoma, a form which prob-
ably lived in the caves soon after they began to form. The bones of
many of the larger animals show evidence of having been gnawed
by rodents, and the tooth marks appear to be those of Neotoma.
Aplodontia, Thomomys, and Citellus, burrowing rodents, come
next in order of abundance. Lepus is quite common, a fact which
might be explained by presence of the lynx, which feeds so largely
on rabbits, and, living in caves, brought in its prey to be devoured.
The remains of other rodents which do not live under the ground
were doubtless washed into the caves by the seasonal rains.

The asphalt deposits were formed from the surface accumu-
lation of tar in which animals were caught, and we find the num-
ber of rodents exceedingly small, in fact a minimum as compared
with the bones of carnivores. This is explained by the fact that
the latter were attracted to these pools by animals entangled in
the tar, and rodents would be caught only by straying acci-
dentally into the pools.

"1 Seience, vol. 17, no. 435, pp. 708-712, 1903.

* Amer. Jour. Sc., Ser. 4, vol. 22, 1906, p. 235-247, 1906.
3 Merriam, J. C., Mem. Univ. Calif., vol. 1, no. 2, 1911.

1912] Kellogg: Pleistocene Rodents of California 153

As to the age of the deposits, those of Potter Creek Cave,
containing the greater number of extinct species, are considered
older than those of Samwel Cave, and the asphalt beds might be
placed between the two, or are perhaps the oldest of the three.
It is a noteworthy fact in the case of all of the deposits that,
while among the carnivores and ungulates there are genera now
extinct, the rodents all belong to living genera, although some
are described as new species. The persistence of rodent forms is
quite remarkable, as they have changed but little through a long
period.

Inasmuch as the rodents are considered especially good indi-
eators of environment and climate as shown in the life zones,
it was hoped that they might furnish some evidence as to changes
in climate during Pleistocene time; but when we find in the caves
forms which belong to the present Canadian Zone mingled with
those of the Transition and even Upper Sonoran, and all found
at the various levels at which rodents occur in the deposits, it is
difficult to draw conclusions, and this wide range of forms would
not necessarily indicate that the climate differed greatly from
the present one of the regions in which the deposits occur.

The rodent fauna of the caves is not one which accords with
the present topography of the region, a fact which is pointed
out very forcibly by Dr. Sinclair in reference to Potter Creek
Cave, when he says that ‘‘the present mountainous character of
the country is entirely out of harmony with the existence of
mastodons, elephants, and tapirs.’’ The rodent forms Castor,
Aplodontia, and Microtus suggest that the cave regions of Shasta
County were more humid at the time of accumulation of these
deposits than they are at the present day. Two forms of ground
squirrel and three of the rabbit group would indicate a fairly
level country with grass and brush, while three forms of tree-
squirrels would show that the country included forest areas.
Presuming that the region was better watered and partly for-
ested, it is possible to account for the number of forms belonging
to the Canadian Zone. These two factors combined might permit
the presence of a fauna of a higher zone, although the climate
would not necessarily be much colder than it is to-day.

The rodents of the Rancho La Brea deposits are close to the

154. University of California Publications in Geology (Vou.7
forms living in this region at the present time, and are definitely
of the Upper Sonoran Zone, and of a plains country. It is there-
fore difficult for us to belheve that any marked changes in climate
or topography have occurred in this region since the period of
accumulation of the remains representing the Rancho La Brea
fauna.

List or RopENTS ARRANGED ACCORDING TO EXISTING LiIFE-ZONES

POTTER CREEK CAVE

UPPER SONORAN

Citellus b. douglasi
Lepus californicus
Sylvilagus auduboni

UPPER SONORAN

Citellus b. douglasi
Peromyscus m. gambeli
Sylvilagus auduboni

UPPER SONORAN

Citellus b. captus, n. subsp.

Peromyscus m. gambeli
Microtus californicus

Thomomys b. pallescens

Perodipus agilis
Sylvilagus auduboni

Sylvilagus b. cinerascens

TRANSITION

Citellus b. douglasi
Hutamias, sp.
Microtus ealifornicus
Thomomys microdon
Thomomys leucodon

SAMWEL CAVE
TRANSITION

Sciurus g. fossilis, n. subsp.
Castor subauratus
Peromyscus m. gambeli
Microtus californicus
Thomomys microdon
Thomomys leucodon

RANCHO LA BREA

BOREAL

Arctomys flaviventer
Callospermophilus chrysodeirus
Seiurus albolimbatus
Sciuropterus a. klamathensis
Aplodontia m, fossilis
Neotoma ec. occidentalis

Lepus a. klamathensis

BOREAL

Callospermophilus chrysodeirus
Seiurus d. albolimbatus
Seiuropterus a. klamathensis
Aplodontia m. fossilis
Neotoma e¢. occidentalis
Erethizon epixanthum

Lepus a. klamathensis

SPECIES IN CAvE FAUNAS

ARCTOMYS FLAVIVENTER Aud. and Bach?

An incisor and the anterior portions of two lower mandibles

from Potter Creek
not to be found in

Cave represent this species. Arctomys is now

the Shasta region.

One incisor is larger and

has a more marked orange color than those of specimens from the
Sierra. In the first character it approaches the Alaska form, but

the color seems to be a variable character.

tively referred to A. flaviventer.

The material is tenta-

1912] Kellogg: Pleistocene Rodents of California 155

CASTOR SUBAURATUS Taylor

Castor occurs in Samwel Cave only, and is represented by
three upper molars, right M’, left M’, and right M?.

A new species, Castor subauratus,* has recently been de-
seribed from the San Joaquin Valley, California, and although

Castor subauratus. Right M', posterior view, no. 19508.
Castor subauratus. Right M"', occlusal view, no. 19508.
Castor subauratus. Right M7’, occlusal view, no. 17318.
Castor subauratus. Left M?, occlusal view, no. 19507.

Sciurus g. fossilis, n. subsp. Right lower mandible, no. 19506.

il.

Fig. 4.
5.

a6:

Lepus a. klamathensis. Left lower mandible, no. 9575.

Figs. 1 to 6 natural size.

the specific differences do not include any points in regard to
the teeth as separating it from C. pacificus, the more northern
form, it is probable that these three molars belong to the Cali-
fornia species. Mr. Taylor considers C. suwbawratus to be a long-
isolated form and one which crossed the mountain barrier from
the north. The Shasta region is the known northern limit of the
species.

CITELLUS BEECHEYI DOUGLASI (Richardson)

A number of specimens of this ground-squirrel were found
in both Potter Creek and Samwel caves at depths of from one
inch to ten feet. All are lower jaws with the exception of frag-
ments of two skulls, found one in each of the caves. No differ-

4 Taylor, W. P., ‘‘The Beaver of West Central California,’’ Univ. Calif.
Publ. Zool., vol. 10, p. 167 (1912).

156 = University of California Publications in Geology [Vou.7

ence can be detected between the fossil forms and those of to-day.
The presence of the ground-squirrel in both caves indicates
that some of the surrounding country during the time of
accumulation of the deposits was rather dry and open, although
not necessarily low zonally. Now, as then, Citellus b. douglasi
can be found associated with Callospermophilus chrysodeirus,
Sciuropterus klamathensis, and Sciurus albolimbatus, forms of
the Canadian Zone, showing that it has a wide range of habitat
as far as temperature is concerned.

CALLOSPERMOPHILUS CHRYSODEIRUS (Merriam, C. H.)

Three specimens of this squirrel, all lower jaws, were found
in each of the caves, but at a greater depth in Potter Creek Cave
than in Samwel Cave. The fragmentary nature of the material
makes a subspecifie differentiation impossible, and yet the teeth
of the specimens from Potter Creek Cave are slightly heavier
than in the living species. The specimens from Samwel Cave
unfortunately lack teeth.

EUTAMIAS, sp.

A portion of a lower mandible without teeth from Potter
Creek Cave represents a form of Eutamias, but from this one
fragment the specific status cannot be determined. Its small size
would place it nearest to Eutamias amoenus.

SCIURUS GRISEUS FOSSILIS, n. subsp.

Type no. 19506, from Samwel Cave. Anterior portion of right
lower mandible with P, and broken incisor.

This type, which is the only specimen of Sciurus griseus
found in either cave, has such width across the anterior portion
of the mandible as to make it strikingly unlike the living forms
of griseus which attain their maximum size here in the west, and
yet do not approach the fossil form in that respect. The incisor
is broken, but the small fragment of it left shows that it is not
of especially large size. The P, is much worn. It is not larger
than that of the living form, but the fact that the mandible is
so extremely wide seems sufficient ground for subspecifie differ-
entiation. It is unfortunate that more material representing

1912] Kellogg: Pleistocene Rodents of California 157

this new form is not available for, judging from the size of the
mandible, the skull might exhibit striking and interesting differ-
ences in other respects. Measurements comparing the fossil form
with the two largest specimens of S. griseus from the collection
of the California Museum of Vertebrate Zoology are given below.

MEASUREMENTS

No. 19506 No. 11362* No. 11359*
Width of mandible at Py -.............22-..-.2-------- 14.3 mm. 11.8 11.
Width of mandible at Mg ................-----...---- 13.7 10.6 10.7

* Calif. Mus. Vert. Zoology.

SCIURUS DOUGLASI ALBOLIMBATUS Allen

This species is scantily represented by two lower mandibles
from Samwel Cave and a portion of the skull with some upper
teeth from Potter Creek Cave, but the material is sufficient to
establish its status under this species.

SCIUROPTERUS ALPINUS KLAMATHENSIS Merriam, C. H.

Four lower mandibles, two from each cave, have been referred
to this form. This species represents a zone of high altitudes
to-day, and seems especially fond of red fir, Abies magnifica, as
a habitat, but it has been found as low as 4500 feet elevation,
where red firs do not exist. As has been mentioned above it occurs
in the same locality with Citellus b. douglasi, so there is no
apparent anomaly in their being found together in the caves.
Their scarcity, however, and that of the two preceding genera,
Arctomys and Callospermophilus, would indicate that these three
animals and others which follow (Aplodontia, Neotoma cinerea,
and Lepus klamathensis), all forms of the Canadian Zone, were
here probably near their lowest limit of distribution.

APLODONTIA MAJOR FOSSILIS Sinclair
This form was described by W. J. Sinelair,? the type being
a right mandibular ramus from Potter Creek Cave, lacking the
coronoid process and part of the angle. The subspecifie char-
acters given are that the dental foramen is wider transversely
than in the living species, that the ridge in front and below the

5 Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, no. 7, p. 147, 1905.

158 University of California Publications in Geology \Vou.7

masseteric fossa is usually continued across the lower side of the
ramus to the inner prominence of the angle, and that the wall
in front of the fossa above the angle, on the inner side of the
ramus, is vertical for a relatively long distance below the open-
ing of the alveolar canal. A large number of mandibular rami
and a few fragments of skulls showing the upper tooth rows and
palate are found in both caves, and a careful study of these,
together with five skulls of Aplodontia major from the collection
of the California Museum of Vertebrate Zoology taken in the
Shasta region, shows that not only is the shape of the dental
foramen not constant, but that the other two characters given
vary according to the age of the individual, the continuation of
the ridge across the ramus and an excessive vertical height gener-
ally indicating age. In taking measurements of the upper and
lower tooth rows in the fossil specimens, a range of variation was
found, from a Samwel Cave specimen with a lower tooth row of
16.7 mm., up to one from Potter Creek Cave measuring 20.5 mm.
The conclusion is that these specimens represent individuals of
all ages from very young to very old. On the whole, the lower
tooth row of the fossil specimens averages slightly longer than
in the living species, the average length of twenty-five specimens
from Potter Creek Cave being 18.6mm.; so that this factor,
taken in conjunction with the fact that the ridge across the
rami of the fossil specimen is, on the whole, slightly more pro-
nounced than in all but one of the five specimens of A. major,
would support the view that the fossil form is a distinct sub-
species.
PEROMYSCUS MANICULATUS GAMBELTI (Baird)

A portion of the skull with left upper tooth row from Samwel
Cave has been referred to this widely distributed species of the
genus, as it presents no characters which might distinguish it
specifically.

NEOTOMA CINEREA OCCIDENTALIS Baird

Of all the rodents the most abundant remains from both caves
are those of Neotoma. They occur at varying depths in abund-
ance, but unfortunately consist chiefly of lower mandibles. A
new species, Z’eonoma spelaea, has been described from Potter

1912] Kellogg: Pleistocene Rodents of California 159

Creek Cave by W. J. Sinelair,® the type being the ‘‘anterior two-
thirds of a skull of an adult individual, in which the teeth are
not much reduced by wear,’’ and the main points of differentia-
tion being that in the fossil form ‘‘the rostrum and _ incisive
foramina are decidedly shorter . .. than in 7. cinerea . . . the
premaxillae extend farther back beyond the nasals, the nasals
taper more posteriorly, and the frontals have a greater inter-
orbital width.’’? Also in the lower mandibles of 7. spelaea ‘‘the
enamel loops of the molars [are] more evenly balanced on the
two sides of the axis of the tooth row.’’ According to E. A.
Goldman’ in his revision of the genus Neotoma, typical N. cinerea
is not considered to range into northern California, but instead
that region is occupied by N. c. occidentalis. The following com-
parisons are made with specimens of that subspecies.

The type of Teonoma spelaea, no. 5362, is the only specimen
available from which all the measurements in support of the
various specific characters can be obtained; moreover the skull
is that of a young adult individual which may not have attained
full size. There are two other portions of skulls from Potter
Creek Cave, nos. 3550 and 6341, but they are broken so that
measurements of all the points cannot be taken. In Samwel
Cave all the specimens found were lower mandibles, so no cor-
roborative measurements can be obtained from that source.
Taking, therefore, the measurements of the type only as given in
the description already cited, and comparing them with those
of three specimens of young adult females of N. c. occidentalis,
from the collection of the California Museum of Vertebrate
Zoology, it is found that in the type of the fossil form the
incisive foramina are longer, and the rostrum, that is the dis-
tance from the base of P* to the anterior face of the incisor, is
longer. The extension of the premaxillae is less than that of one
of the specimens with which it is compared, and greater than
that of the other two, showing that this is a variable character.
The frontal width is less than a millimeter greater. The main
points in which the fossil form differed from N. c. occidentalis
were in a longer upper tooth row and larger teeth, points which,

*Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, no. 7, p. 147, 1905.
7N. Amer. Iauna, no. 31.

160 University of California Publications in Geology [Vou.7

if taken in conjunction with the facet that the rostrum and in-
cisive foramina really were shorter, would further strengthen the
specific differences of 7’. spelaea; but in the light of the fact that
the two latter points have been disproved, the fact that the tooth
row is longer would hardly seem a ground for specifie differen-
tiation. In regard to the enamel loops of the lower molars being
more evenly balanced in the fossils, no difference between them
and those of N. c. occidentalis could be found and the writer has
placed all the specimens from both caves under this living species.

Some of the lower mandibles from both caves have been
referred to another species, N. fuscipes, but there is a well-
marked difference in the shape of the mandibles of the two forms,
and the fossil specimens can all be readily distinguished as
belonging to the N. cinerca group. N. cinerea and N. fuscipes
have been taken in the same localities, but as a rule they do not
occupy the same territory and it is evident that the fossil speci-
mens are those of the former group, which now lives among rocks
and might have lived in the caves, rather than those of the latter
group, which build houses of sticks above ground.

MICROTUS CALIFORNICUS (Peale)

Three specimens only of this genus occur in the caves, two
from Samwel Cave and one from Potter Creek Cave. The species
M. californicus is one which inhabits comparatively dry ground.
It is, therefore, not surprising to find it in the cave deposits, but
the fragile nature of the skull would make its preservation un-
common under any circumstances. A lower mandible from
Samwel Cave has a complete set of teeth, and the one specimen
from Potter Creek Cave is a portion of the skull with dentition,
so that the species can be definitely placed.

THOMOMYS MICRODON Sinclair

This seems to be a well-defined species described by Sinclair®

‘

as differing from Thomomys mazama ‘‘in having a very promi-
nent ridge on the side of the fossa, marking externally the posi-
tion of the alveolus of the superior incisor, and with a deep

fossa above the ridge.’’ Also the rostrum is short and broad.

® Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, p. 146, 1905.

1912] Kellogg: Pleistocene Rodents of Califorma 161

Fig. 7. Thomomys microdon. Anterior portion of skull, left side, no.
5738.

Fig. 8. Thomomys leucodon. Anterior portion of skull, inferior view,
no. 4649.

Fig. 9. LThomomys leucodon. Anterior portion of skull, left side, no.
5622.

Fig. 10. Thomomys leucodon. Anterior portion of skull, inferior view, no.
5622.

Figs. 7 to 10 natural size

The writer has referred a number of lower mandibles—about a
dozen from each cave—to this form on account of their small
size, and one portion of a skull from Potter Creek Cave which
corresponds closely to the type specimen. In Samwel Cave the
specimens were found at depths varying from near the surface
to thirty-six inches, in Potter Creek Cave from four inches to
one hundred and sixty.

THOMOMYS LEUCODON Merriam, C. H.?

There are six specimens, one an anterior portion of a skull
without teeth, no. 4649, from Samwel Cave, another anterior
portion of a skull with incisors, P*, M', and M?, no. 5622, and
four lower mandibles from Potter Creek Cave, which, on account
of their size and shape, have been placed under the lewcodon
group of Thomomys. There are certain characters shown by
these specimens, especially the fragments of skulls, in which they
differ from specimens of 7. leucodon navus from the collection
of the California Museum of Vertebrate Zoology. No typical
specimens of 7. leucodon were available, but the skulls of the
subspecies navus do not differ from those of the typical form in
the points mentioned.

In the fossil specimen, no. 4649, from Samwel Cave the in-

162 University of California Publications in Geology [Vou 7

cisive foramina are wide, and open, and they are two very dis-
tinct parallel ridges running from these foramina to the base of
the premolars. The skulls of Thomomys l. navus show incisive
foramina differing in that some are more open and that the ridges
are sometimes present and sometimes lacking, due probably to
the age of the individual. In no. 5622 the incisors apparently
pass abnormally far back of the anterior roots of the zygomata,
but the specimen is broken so that the incisors are exposed, and
it is possible that the length appears abnormal compared with
unbroken skulls. In this specimen the incisive foramina are
not as wide open, nor are the ridges as apparent. One lower
mandible has very small teeth, and yet it is evidently not that
of a young individual, and the angle of the jaw is much ex-
tended. If these various characters were all combined in one
individual there would seem to be ground for separation of a
subspecies, but in view of the fact that each one presents only a
slight difference, and that the material is so fragmentary, they
have been placed under the ving species. They seem to come
under the 7. lewcodon group rather than under 7. monticola,
because in 7. monticola the root of the incisor curves down ab-
ruptly in front of the anterior root of the zygomata, while in
T. leucodon the root of the incisor slopes off more gradually and
passes almost directly back of the root of the zygomata.

ERETHIZON EPIXANTHUM Brandt

The genus Erethizon is known only from Samwel Cave, but
it is the most fully represented of all the rodents. A nearly
complete skeleton with the skull, no. 11376, was found, and also
a skull with the left ramus of the lower jaw, no. 8901.

A comparison of the fossil specimens with a Recent individual
from the collection of the California Museum of Vertebrate
Zoology, no. 16216, from the Whitney Creek, Tulare County,
California, and with five skulls from the collection of the U.S.
National Museum, nos. 108991, 109142, and 109143 from Tuol-
umne Meadows, and nos. 109276 and 11082 from Mt. Dana,
California, showed no points of difference either in the skeleton
or skull which would separate the fossil form from the living
species. Specimen no. 11276 is a comparatively large skull, and

1912] Kellogg: Pleistocene Rodents of California 163

Fig. 11. Erethizon epixanthum. Inferior view of skull, no. 11276, k 4.

the auditory bullae seemed to be unusually long, anteropos-
teriorly, and inflated, but it is that of a young individual, and it
seems to be a fact that the bullae shrink and contract with age,
so that the general shape of the bullae rather than their size
would constitute a dependable character and, in this case the
form of the bullae of the fossil specimen is similar to that of the
living species. Even such a small series of skulls of the living
species showed so much variation that no comparative measure-
ments are given.

MEASUREMENTS OF SPECIMENS FROM SAMWEL CAVE

; — No.11276 No. 8901
Length of skull from anterior face of incisors to back

OPO COND UG perc w state cae eee eae arene eee reece a Sete o 107.5 mm,
Anteroposterior diameter of bullae ..................22.-2-22:--++ 21.2 19.
Transverse diameter of bullae

LEPUS CALIFORNICUS Gray

There are about two dozen specimens consisting of lower
mandibles and two portions of skulls from Potter Creek Cave
referable to this species. There are some slight points of differ-
ence, however, in the fossil forms, such as proportionately great
length of the lower tooth row and diastema in relation to the
size of the mandible. The upper tooth row is slightly longer,
and the anterior width of the incisive foramina somewhat greater

164 University of California Publications in Geology [ Vou. 7

than in the living species, but there is such variation in the
measurements, dependent upon age and sex, that such slight
differences hardly seem a sufficient ground for even subspecifi¢
separation. It seems rather remarkable that ZL. californicus,
which is so abundant among the Potter Creek Cave rodents,
should not be represented in Samwel Cave.

LEPUS A. KLAMATHENSIS (Merriam, C. H.)

This form of the varying hares is represented by four man-
dibles from Potter Creek Cave. Eleven mandibles and a portion
of a skull with the left upper tooth row, except for P*, and the
anterior root of the zygomata are known from Samwel Cave. In
size these specimens might be confused with Sylvilagus auduboni,
but there are distinctive differences that make their determina-
tion fairly certain. In the mandible of LD. a. klamathensis the
inner point of the posterior columns of the lower molars curves
away from the anterior column, while in S. auwduboni the two
columns are practically parallel, and in addition the angle is
sharper and begins farther back in LZ. a. klamathensis than in
S. audubom. Furthermore, in L. a. klamathensis with age a ridge
develops on the outer side of the anterior root of the zygomata,
which is not so pronounced in S. auduboni.

SYLVILAGUS AUDUBONT (Baird)

Nine specimens from Potter Creek Cave and seven from
Samwel Cave, all mandibles except two, a right and left upper
jaw without teeth, are referred to this species. It is possible that
these are young specimens of L. klamathensis, but they would be
extremely young to be as small as they are, and the teeth in these
Specimens seem to indicate full-grown individuals. It is inter-
esting to note that this species was common at a point so far
north as this region.

SPECIES FROM Rancuo La BrEA
CITELLUS BEECHEYI CAPTUS, n. subsp.

Type no. 11264, a portion of the skull without nasals, pre-
maxillae and incisors, Cotype no. 12404, a left ramus of the
lower jaw with P,, M,, M,. Both specimens from locality no.
1059, Rancho La Brea, Los Angeles County, California.

1912] Kellogg: Pleistocene Rodents of California 165

In the skull the width between the premaxillae and the an-
terior width of palate are less than in Citellus b. fisheri. The
bullae are relatively long and narrow. In the lower jaw, the
tooth row is long and the teeth heavy in proportion to the size
of the ramus; the coronoid process, angle, and condyle are small.

Fig. 12. Citellus b. captus, n. subsp. Inferior view of skull, no. 11264.
Fig. 13. Citellus b. captus, n. subsp. Superior view of skull, no. 11264.
Fig. 14, Citellus b. captus, n. subsp. Right lower mandible, no. 12404.
Fig. 15. Thomomys b. pallescens. Right side of skull, no. 11269.

Fig. 16. Sylvilagus auduboni. Left upper tooth row, no. 1870.

Figs. 12 to 16 natural size.

On the whole, this form seems to be a relatively small one,
although comparisons with Citellus b. fisheri show only slight
differences in measurements of some of the parts. Taken as a
whole the known differences seem sufficient ground for at least
subspecifie differentiation. The comparative measurements are

166 University of California Publications in Geology [Vou.7

with Recent spetimens from the collection of the California
Museum of Vertebrate Zoology, which correspond to the fossil
forms in stage of wear of the teeth, and are therefore considered
to be of comparable age.

MEASUREMENTS
No. 11264 No. 1407*
Weastatemmo oral Mores chy eseceses-ceceseeeseecceeneesescee ree ee senses 13. mm. 15.
Anterior width between premaxillaries -.............2.2...... ik, 13.6
Anterior width of palate at P® -.......2.-------:cc-ccceeeeeeeeeeeee 8.3 Geil
Posterior width of palate back of M® _.......2.....2.-:-- 8.2 9.1
Length of upper tooth row 17 11.9
Anterposterior diameter of auditory bullae -................. 12.3 11.2
Transverse diameter of auditory bullae ...................-.2------ 8.4 11.2

No. 12404 No. 3183*

Weng phy os Lowers G00 tier 0 yy essen ent enn enone 11.8 mm, A,
AMET OPOSLETION (lam ever Ol euetecessewseteeeneeeeaeeceneeecueseaece 2.5 2.
Anteroposterior diameter of My __....--..2-.-----:c-eec-seeeceeee-e= 2.5 2.3
Anteroposterior diameter of My .......2.-::::::eeceeeeeess 2.8 2.5
Transverse diameter of Py -..22..2.0....0ceeeee eee eee eevee eee eee 2.2 2.1
Mramsverse ‘diameter oy Wigs ssscecseessseetee sees eeeneenen eee 3. 2.7
Mramsyersey dlameter 1.0 ty Vs eeeeces eee eer essa ene eee oe 3.2 3.

* Calif. Mus. Vert. Zool.

PEROMYSCUS GAMBELI (Baird) ?
This genus is represented by only one specimen, a right ramus
of the lower jaw, with M,. It is a small form near the size of
P. gambeli, the smallest of the Peromyscus species.

MICROTUS CALIFORNICUS (Peale)

This species is represented by abundant material. One of the
distinguishing skull characters of MW. californicus is the form of
the incisive foramina, which are of uniform width, instead of
narrowing anteriorly or posteriorly as in other species. In one
specimen, no. 18700, a portion of the skull, the incisive foramina
are of this shape. Other specimens referred to this species are
the anterior portions of a right and left ramus of the lower jaw
with P, and incisor; two right rami with incisor and condyle;
the anterior portion of a left ramus with incisor; one with incisor
and M, and M,; and a portion of a skull with palate and M? and
M* on either side.

1912] Kellogg: Pleistocene Rodents of California 167

THOMOMYS BOTTAE PALLESCENS Rhoads

The specimens of Thomomys represented in the Rancho La
Brea fauna show quite a range of variation due to differences in
age, the younger individuals with a short rostrum and slender
jugal and with the rami of the lower jaw small, the older ones
with more elongated rostrum and larger rami. They have all
been placed under the subspecies 7’. b. pallescens because they
present no greater range of variation than is present in this
species. The teeth of two specimens, no. 1212, a left ramus of the
lower jaw with M, and M,, and no. 12418, a right ramus of
the lower jaw with incisor and P,, M,, M,, are slightly different
from those of 7. pallescens, but in the case of no. 1212 the effect
is partially due to a break in M, which gives it a very broad
appearance. However, the teeth of the fossil form are slightly
heavier than those of typical 7. pallescens.

PERODIPUS AGILIS (Gambel)

One specimen, a portion of the skull showing the premaxil-
laries and frontals and three teeth, P*, M’, M’, embedded in a
piece of asphalt, represent this species. The teeth make it refer-
able to Perodipus rather than to the externally closely related
genus of pocket rats, Dipodomys.

SYLVILAGUS AUDUBONI (Baird)

This species is the best represented rodent found in the Rancho
La Brea deposits. There are eleven specimens, mostly mandibles.
There are two fragments of skulls, one of which has a full set of
teeth on the left side. The fossil forms are those of fairly
young animals, thus bearing out the theory already stated by
Dr. J. C. Merriam that the very young animals through lack
of discretion, commonly fell victim to the asphalt. The speci-
mens have been referred to S. auduboni instead of to the sub-
species sanctidiegi, because the latter is based mainly on a
geographic distribution, and although it is supposed to differ
from S. auduboni in having narrower and more slender jugals
and a broader palatal ridge, a comparison of skulls of the two
forms did not bear out the latter distinctions.

168 University of California Publications in Geology [Vou.7

SYLVILAGUS BACHMANT CINERASCENS (Allen)

Of this more uncommon brush rabbit only three specimens
occur, portions of three right mandibles, with dentition. The
teeth of one are so broken that their true shape is indistinguish-
able, and those of the other two show that they belong to very
young individuals. The small size of all three makes them
referable to this form, which is the smallest species of the genus
found in this region. There seem to be some slight differences
in the shape of the teeth between the fossils and Recent speci-
mens of S. b. cinerascens, but this can be accounted for on the
ground that the fossil teeth are unworn.

thee
IFORD

Issued January 8, 1913

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Andrew C. Lawson .....2.:-..-.c-tta2nte-sseececesecassoenesstetessencenedievctnesientaca2er Sapa aa er
4, Triassic Ichthyopterygia from California and Nevada, by John C. Merriam..
6. The Igneous Rocks near Pajaro, by John A. Reidesi..io...--< ceccsscececcctees een
7. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller |
8. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by |
9
0
1

drow. C. Laweon : 22 ae ee os alte aosnise aati ce ee
. Palacheite, by Arthur S. Eakle......... i clatsegnteseesnsasnsepsceediceasaiigavndeeenn2iste See or {
. Two New Species of Fossil Turtles from Oregon, by O. P. Hay.
. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair.

Nos. 10 and 11 “in, one Gover p.. isco, tecceece ne tesetee ec ttec cece ee é
12. New Ichthyosauria from the Upper Triassie of California, by John C. Merriam.....
18. Spodumene from San Diego County, California, by Waldemar T. Schaller..........
14. The Pliocene and Quaternary Canidae of the Great Valley of California, by

John. C, Merriam -....250) cc. t ese ool dihveat Sh bbanesieks cannes eee eee er
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson ‘
16. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam...
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by tage CG.

Tharwson. sch eee cele he se paper eceus seeded nactnae ee rr
18. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. cyan
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmon —
20. Euceratherium, a New Ungulate from the Quaternary Caves of Chi by

William J. Sinclair and E. L. Burlong 2.22 uci cacao eee pee
21. A New Marine Reptile from the Triassie of California, by John C. Macca oeesecaae
22. The River Terraces of the Orleans Basin, California, by Oscar H. Hershey........
VOLUME 4.
1. The Geology of the Upper Region of the Main Walker River, Nevada, by Dwight
LD ss) 1 Oia ae ne eee fas RUNS 5 ss) AON BP OO Pe eres eet
2, A Primitive Ichthyosaurian Limb from the Middle Triassie of Nevada, by John a
Wie reed earn sg Ss ae ea so
3. Geological Section of the Coast Ranges North of the Bay of San Francisco
Vi. GC. OSMONE -..22.22-neeeeesece een eecene ence nenee ee nenenncnesneceeereraesnnne senasersenanaduccenennenaren sanrenenene sansa

4, Arcas of the California Neocene, by Vance C, Osmont.......---------------n---cs0---000
5, Contribution to the Palaeontology of the. Martinez Group, by Charles HE. Wear
6. New or Imperfectly Known Rodents and Ungulates from the John Day Series,
William J. Simelair 2..c.--.2-scccee2-scccccesce nee tenemere ne eee reeenpaedeer cen neses seemnses==nesnannneanenbenraeee

. New Mammalia from the Quaternary Caves of California, by William J. Si
Preptoceras, a New Ungulate from the Samwel Cave, California, by Eusta
Furlong — -....--2---2seccececsceeececncesecenenseeenecesesenenenssnaneeensnencsnessasussessnesusarranerocasncscassacsnansns =

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 9, pp. 169-175 Issued January 8, 1913

TAPIR REMAINS FROM LATE CENOZOIC
BEDS OF THE PACIFIC COAST
REGION

JOHN C. MERRIAM

CONTENTS
PAGE
TATE Ui WO» ee a eee 169
Specimen from Auriferous Gravels of California _............... STEER: 170
Specimen from Marine Beds at Cape Blanco, Oregon ................---.------.---- 172
SS CATT) BA Ty ue eR re nee = Su Beer OI Oe et 175
INTRODUCTION

The only certainly known remains of Tapiridae from the
Pacifie Coast province of North America consists of two speci-
mens. One is a single tooth obtained many years ago from the
Auriferous Gravels of California. The other specimen is a por-
tion of an upper jaw with teeth, recently discovered in marine
deposits near Cape Blanco, Oregon. As this material is of con-
siderable importance in a study of late Cenozoic history of the
Pacific Coast region, it is desirable to place on record such
information relating to it as is available.

For the California specimen, which was presented to the
University some years ago, the writer is indebted to Dr. Wm.
J. Sinclair, through whom it was given to the University by Mr.
Benjamin Pownell.

For the privilege of examining and describing the second
specimen the writer wishes to acknowledge his indebtedness to
Mr. Frank M. Anderson and to Mr. Bruce Martin of the Cali-
fornia Academy of Sciences.

170 University of California Publications in Geology [Vou.7

SPECIMEN FROM AURIFEROUS GRAVELS OF CALIFORNIA

A lower molar tooth presented by Mr. Benjamin Pownell to
the University of California some years ago is the only available
specimen representing the Tapiridae in California. This tooth
was originally in the collection of Dr. Snell, and as suggested
by Dr. Wm. J. Sinelair, who obtained it from Mr. Pownell, it
may be the tooth to which reference is made by Wm. P. Blake and
later by J. D. Whitney. In a note on the occurrence of fossil
remains of the tapir in California published in 1868, Blake’
stated that remains of this animal had been found at a depth of
forty feet below the surface in the auriferous gravels at Wood’s
Creek near Sonora, Tuolumne County, California. The speci-
mens were said to have been presented to Blake by Dr. Snell of
Sonora. The material consisted of a lower molar and possibly an
epiphysis of a cervical vertebra. The tooth was determined by
Professor Owen of the British Museum as the ‘‘crown of the
left lower molar tooth of a tapir.’’ The specimen mentioned
by W. P. Blake is referred to by J. D. Whitney? in 1879 in his
discussion of the Auriferous Gravels.

Figs. la to le. Tapirus haysii californicus, n. subsp. M.(?). No. 8747,
natural size. From the Auriferous Gravels of California. Fig. la, outer
view; fig. 1b, superior view; fig. lc, inner view.

The tooth presented to the University by Mr. Pownell is a
left lower molar. It is apparently M,. It seems to be dis-
tinguished from M, mainly by the relatively greater width of
the posterior half of the tooth. The anterior and posterior
transverse ridges are unworn and show only faint indications of
notches between protoconid and metaconid, and between hypo-
conid and entoconid. There is an anterior and a_ posterior

1 Blake, Wm. P., Amer. Jour. Se., ser. 2, vol. 45, p. 381, 1868.
2 Whitney, J. D., Mus. Comp. Zool., vol. 6, p. 250, 1879.

1913] Merriam: Tapir Remains from Pacific Coast Region 171
I g

cingulum. The posterior cingulum is narrow transversely. On
the anterior side of the crown there are two basal ridges. One
is median and is partly confluent with the anterior ridge of the
protoconid. The other anterior basal ridge lies below and in
front of the one just described, and forms a distinct shelf on the
external side of the anterior end of the tooth. It reaches nearly
to the extreme outer border of the tooth. On both the outer and
inner sides of the tooth small tubercles are developed between
the bases of the anterior and posterior transverse ridges. The
inner tubercle is very faint, but the outer one is a noticeable
feature of the tooth (see figs. la to 1c).

The specimen just described does not differ greatly from M.
and M, of EHlasmognathus bairdu. It is distinguished by the
slightly larger anteroposterior diameter of the anterior basal
ridges, and by the smaller size of the external basal tubercle
between the metalophid and hypolophid. In the only specimen
of EF. bairdii available for comparison the posterior molars are
somewhat worn and the characters of the transverse ridges are
not as clearly shown as in the fossil specimen.

In such figures of the dentition of Tapirus terrestris as are
available, the characters of M, seem very close to those of the
fossil from California, though the details of form are not clearly
discernible on any figures of 7. terrestris at hand.

The type specimen of T'apirus haysw figured by Leidy* seems
to show anterior and posterior cingula, and an external basal
tubercle between the metalophid and hypolophid. The width or
transverse diameter of the tooth is, however, relatively much
greater compared with the length or anteroposterior diameter, the
relation being as 22.3:27 in 7. haysii, and 17.8: 25.3 in the Cali-
fornia specimen. As the teeth compared are both presumed to
represent M, of the left side, it would seem that the considerable
variation in width, amounting to at least twelve per cent, may
represent specific or subspecifie difference. In Hlasmognathus
bairdu the ratio of width to length is intermediate between that
in the California specimen and that in the type of 7. haysv.

3 Leidy, J., in Holmes, Post-Pleiocene Fossils of South Carolina, pl. 17,
figs. 7 and 8, 1860.

172 Umversity of California Publications in Geology [Vou.7

The tooth from California represents a form approaching
Elasmognathus bairdi of the Recent fauna in certain characters.
In some respects it is intermediate between E. bairdw and
Tapirus terrestris. Though the California specimen shows some
resemblance to 7’. haysii, the considerable difference in form of
M, makes it very difficult to believe that the two are specifically
identical. The specimen seems at least as near E. bairdii as to
any described species, but the nature of the cingula and of the
tubercles between metalophid and hypolophid seem to distinguish
it from that form. The writer considers that a tentative recog-
nition of the distinguishing characters of the California specimen,
together with an indication of its geographic location, is more
desirable than a very doubtful reference to one of the described
species. This form is therefore tentatively distinguished as
Tapirus haysw californicus.

MEASUREMENTS

No. 87474 E. bairdii T. haysii
M., anteroposterior diameter.......... sotnaceee cose 25.3 mm. 22 27
M., greatest transverse diameter —............ 17.8 17.8 22.3

+ From the Auriferous Gravels of California.

SPECIMEN FROM MARINE BEDS AT CAPE BLANCO, OREGON

The tapir specimen from Cape Blanco, Oregon, was obtained
in June, 1911, by Mr. Bruce Martin while collecting in the marine
beds of that region for the California Academy of Sciences.
It was found in the bluff about three miles south of Cape Blanco
and one-half mile north of the mouth of Elk River. At this
locality the formations comprise two lithologic phases: (1) an
upper, gray-buff sand, which is loosely cemented and_ breaks
down readily; (2) a lower, blue-gray, argillaceous sandstone,
which is better cemented and forms steeper cliff walls than the
upper zone. There is no evident discordance between the upper
and lower zones.

A considerable marine fauna obtained from the upper sand
by Martin seems quite certainly to represent a phase of the
Pleistocene near that of the San Pedro stages. The marine fauna
of the lower sand is distinctly older than that in the upper zone,
and shows some resemblance to that of the upper Merced series.

1913] Merriam: Tapir Remains from Pacific Coast Region 173
} {

The lower fauna is not yet well enough known to permit definite
reference to a stage of the standard time scale, but seems to be
not older than late Phocene or younger than the earlier portion
of the Pleistocene.

The section from which the tapir tooth was obtained has been
described by Diller,? who refers to an upper horizon as the Elk
River Beds. A collection of marine shells from these beds examined
by Dall was referred to as ‘‘probably Pleistocene, all the
species seeming recent, but they may be of the Merced horizon.
... They are not older than the newer Pliocene.’’? The lower
zone at Elk River as described to the writer by Martin is pos-
sibly referred by Diller to the Cape Blanco Beds, the equiva-
lent of the Empire beds. The fauna from the exposures of
the Blanco is considered by Diller as Miocene. Mr. Martin
believes that the lower horizon of blue-gray argillaceous sand-
stone is later than the Empire formation which occurs lower
down in the section in the eliff farther north. According to
Martin the fauna of this blue-gray argillaceous sandstone is much
more recent in character than that of the Empire Beds farther
north. The tapir specimen is reported from the lower beds.

costing,

“dl Be
Fis Ws, OE
A sina aN Ve

\\ ae ff | ! :
bi y u ee
STAD” Lipp : y
Nit y \ ae
UN i NN 1 \
NAMI

Big. 2. Yapirus, near haysii californicus, n. subsp. Superior molar
series, natural size. From early Pleistocene or late Pliocene marine
deposits three miles south of Cape Blanco, Oregon.

The tapir specimen obtained at Cape Blanco consists of a
portion of a maxillary bone with the three molar teeth well pre-
served and but little worn (fig. 2).

5 Diller, J. S., U. S. Geol. Surv. Bull, 196, p. 30, 1902.

174 University of California Publications in Geology (Vou. 7

In the portion of the maxillary present there is nothing to dis-
tinguish the Cape Blanco form from Elasmognathus batrdia.

The molars do not agree exactly in all characters with those
of any species available for comparison. From Tapirus ter-
restris they differ considerably in the much smaller parastyle
of M*. From 7. roulini they are distinguished by the relatively
smaller size and more nearly quadrate form of M*. From 7.
imdicus, they are separated by the more nearly square cross-
section of M*, and by the tendency to development of an external
cingulum on the outer side of the metacone pillar of M*?. The
Cape Blanco form approaches Elasmognathus bairdw in the
nearly quadrate form of M?, and in the presence of a weak
cingulum on the outer side of the metacone pillar of M*. There
is also a faint suggestion of a tubercle on the inner side of M'
between the protocone and hypocone pillars as in EL. bairdu. It
seems possible to distinguish the Cape Blanco form from FE.
bairdii by the weaker external cingulum on the outer side of M?’,
by the absence of a cingulum on the corresponding region of M°,
and by the absence or imperfect development of the tubercle on
the inner wall of the molars between protocone and hypocone.
There is also a less distinctly noticeable evenness of the molars
in form and size in the Cape Blanco form than in the Recent
E. bairdii.

With Tapirus haysu Leidy from the Pleistocene of southern
and eastern United States it is not possible to make an entirely
satisfactory comparison, as no good figures are available. The
specimen figured by Leidy® from the Brasos River near San
Fillipe, Texas, is somewhat worn and the diagnostic characters
are not clearly shown. The dimensions are very near those of
the Cape Blanco specimen. This specimen is evidently near
Tapirus haystii, and may be referred to tentatively as Tapirus,
near haysu californicus.

6 Leidy, J., in Holmes, Post-Pleiocene Fossils of South Carolina, pl. 17,
fig. 1, 1860.

1913] = Merriam: Tapir Remains from Pacific Coast Region 175

MEASUREMENTS

Cape Blanco

specimen E. bairdii T. haysii
M’, anteroposterior diameter ....................... 21.5 mm. 19.5 21.5
M’, greatest transverse diameter ................ 27.3 24 27.5
M?’, anteroposterior diameter ....................... 24.8 22.5 25.5
M’, greatest transverse diameter 30.5 25.9 32
M°, anteroposterior diameter .............. .. 25.7 21.8
M*, greatest transverse diameter 30 25.5

SUMMARY

The tapir specimens from the Auriferous Gravels of Cali-
fornia and from the marine beds of Cape Blanco, Oregon, both
represent species not distinctly removed from the existing
Tapirus (Elasmognathus) bairdit.

The California specimen seems to be near Tapirus hayst, but
shows differences which appear to be of at least subspecifie value.
This form is tentatively referred to as Tapirus haysw califor-
nicus, n. subsp.

The Cape Blanco specimen is near T'apirus haysi, and shows
indication of relationship to Elasmognathus bairdi. It is prob-
ably near the form from the Auriferous Gravels, and is referred
to as Tamrus, near haysv californicus.

The Auriferous Gravel and Cape Blanco specimens both seem
to represent a stage of evolution quite certainly not earlier than
late Pliocene, and probably not older than early Pleistocene.

ORNIA PUBLICATIONS |
E DEPARTMENT OF

TIN

No. 10, pp. 177-241 Issued February 26, 1913

: BY
GEORGE DAVIS LOUDERBACK

UNIVERSITY OF CALIFORNIA PRESS -
os eee ee BERKELEY

UNIVERSITY OF CALIFORNIA PUBLICATIO

Notzt.—The University of California Publications are offered ine €

all the publications of the University will be sent upon request. For sampl

publications and other information, address the Manager of the University
California, U. S. A. All matter sent in exchange should be addressed to
Department, University Library, Berkeley, California, U. S. A. 5

Otto HARRASSOWITZ - R. FRIEDLAENDER & SonN
LEIPZIG BERLIN | x
Agent for the series in American Arch- Agent for the series in America

aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany,
Education, Modern Philology, Philosophy, Mathematics, Pathology, 2
Psychology. Zoology, and Memoirs. :

Geology —Anprew C. Lawson and Jon C. Merriam, Editors. Price per volume,

Volumes 1 (pp. 485), II (pp. 450), IIL (pp. 475), IV (pp. 462), V (pp. 448),
completed. Volumes VI and VII (in progress). .

Cited as Uniy. Calif. Publ. Bull. Dept. Geol:
Volume 1, 1893-1896, 435 pp., with 18 plates, price

Volume 2, 1896-1902, 450 py., with 17 plates and 1 map, price
A list of the titles in volumes 1 and 2 will be sent upon request.

VOLUME 3.
1. The Quaternary of Southern California, by Oscar H. Hershey
2. Colemanite from Southern California, by Arthur S. Eakle
8. The Eparchaean Interval. A Criticism of the use of the term Algonkian,
AMATO W. C. MUA WOT o2-e22leciedeccccenenee ste ecabendducnccteiedecbcutns cobstanecsn aude ca npma ene See eae eee a
4, Triassic Ichthyopterygia from California and Nevada, by John C. Merria
6. The Igneous Rocks near Pajaro, by John A. Reid..........cc..--n.-ccseoscens:ocsuensersoeenenener
7. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller
8. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by
Am Grew. Cs Lai Wn ©... .-0...-ccecceescecteekt cote sevapecanaiy cena t ant Sap eo Ned vaccine aera aoitticscoreil
DU Palacherte, by. Arthur S. ‘Walkley see tie tccetsre decors eee eee pet ae
10. Two New Species of Fossil Turtles from Oregon, by O. P. Hay.
11. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair.

Nos. 10) and 11 im’ onecowver..... 2225. -c..cses0 Ao io cee cctececoanncea eee pe ae

. New Ichthyosauria from the Upper Triassic of California, by John C. Merriam.
. Spodumene from San Diego County, California, by Waldemar T. Schaller..
. The Pliocene and Quaternary Canidae of the Great Valley of Califor
Mion @), Merriam’ <......-.c-s550- the Coe a ee ee eee

. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson.
. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam..
. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew C.

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. Euceratherium, a New Ungulate from the Quaternary Caves of California, by

William J. Sinclair and H, L. Furlomng.........-.---.---.-:-:2--sec2scececoseeserscenenenerensnenenenenenes
. A New Marine Reptile from the Triassic of California, by John C. Merriam -..
. The River Terraces of the Orleans Basin, California, by Osear H. Hershey.......

bo
So

eo 1
Doe

VOLUME 4.

Ms yc Gr eer es We ee eRe eo Soccer atom og Gomsberrresie so
2, A Primitive Ichthyosaurian Limb from the Middle Triassie of Nevada,

C. Merriam ...-...2ese---c--eecnnceceencceercersntceennentenennecccnccesspeecnnesenenannnasnnansnnensrrnannaneysnnae neat
3. Geological Section of the Coast Ranges North of the Bay of San Francise

Wi C® Ob ont ence cece a ae ee ae
4, Areas of the California Neocene, by Vance C. Osmont..........-.---------------

5. Contribution to the Palaeontology of the Martinez Group, by Charles E. We
6. New or Imperfectly Known Rodents and Ungulates from the John Day Series
William J. Sinclair 2.2... -cececcecececeecsecceeeeneereemeneesceorenaesenenenensnesanessnncsaseaseceanes sting -
New Mammalia from the Quaternary Caves of California, by William J. Si
. Preptoceras, a New Ungulate from the Samwel Cave, California, by Eusta

Furlong -2...22------cenencscscseereecsceesnnareneneneccesenserenenccansaneanameacnccsaracs weeeconssenctunanencte

cere

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY

Vol. 7, No. 10, pp. 177-241 Issued February 26, 1913

THE MONTEREY SERIES IN CALIFORNIA

BY
GEORGE DAVIS LOUDERBACK

CONTENTS
PAGE
Part I.—The Santa Clara Valley Region of Ventura County and its
Relationship to the Coastal Region to the North and West.... 179

Mert UNC G10 Nipeg ss ccf eee oe occa areas See rece cece racine ee net sel nscapesstesseieezsezes eanctezscs 179

Previously Described Section North of Santa Clara Valley ............ 180

Vaqueros-Monterey Series of Monterey-Santa Barbara Coastal
TRACE ee ae eo ep sere ee

Apparent Contrasts between the two Regions ..
Opening of ‘‘ Vaqueros’’ Deposition

MhesSespe WorMation: ...2.-.....-2...--cceccennceeceeneeeenene
Upper part of ‘‘ Vaqueros-Modelo’’ Series ........
Region north of Santa Clara Valley -.............
Pe wMIO dl eLO! SANSOM CS 2 soe. o5 oo esc casa ses co cteecnscesecernnecesceteteececesetece 187
Region south of Santa Clara Valley 188
HOS UGS yes. ates Mee cso sarescareusic-accveseassetescectetes 89)
Lithological Types and Nomenclature in Various Fields .................. 189
Relationships of Different Seetions of the Series —........-.0.0.----- 191
MCU SH OMe Saas eee wee con Face cece eas ash scadedusatevedaseactae-seisicacesctececeecessaceusdecssise 192
Parr II.—Critical Review of our Knowledge of the Monterey Series
in California and History of its Nomenclature ~....................... 193
SEATING ID OS CS pen cece a ee ree aS A cco eee ae Uae SS av ees laa fe ovsaeetbeceestenedeezstes 193
Marly, Notices—Previous to 1898 ............0.2---2--ccscscessssceseeeeeeessesseeeeeenens 193
Decade 1893-1903: Recognition of Series as Stratigraphic Unit and
Extension of Knowledge of its Areal Distribution -............... 195
Wammeloweay——MaiwSOuy) WUSQ3) x.z2..de2eeo cece cee cee cers acces seer ceeedecetecotes-s<c 195
oimbmsal—Mair banks, 1896) ...2.2ccec2ccececceteceeeeeceesecscc qrecevenseeseseseceeste 196
Santa Catalina Island—W. 8. T. Smith, 1897-202... 196
San Clemente Island—W. S. T. Smith, 1898 2200002200200... 196
Southern Coast Ranges—Fairbanks, 1898 .....0......2202.-.22:200020 2 197
Point Reyes Peninsula—F. M. Anderson, 1899 _.......2.0.2.02.:20000-285 197
Coast Range Bituminous Rock Distriets—Eldridge, 1901 .......... 197
HS OUMIGMPA CNA DIS GEUC ic. soc- cos cccereeeececectecceesteeesesose--tesee sue cecuensssoentoorese 198
Berkeley Hills—Lawson and Palache, 1902 .0...0....02.200220:2.c20022-- 199
Middle Coast Ranges—Lawson, 1903 _...02222.-.22..-2.-22..e2eeeeeeeeeeeeee eee 199
ampbeedro——Arn old), 1903. oo cicstcccccececcec cee cnetecceeeene cen pectenasdeeecsapeaateceecet 200
Petroleum Districts—Eldridge, 1903 ....000..22220...20.ceeeeeeeeeeeee eee 200

178 University of California Publications in Geology [Vou.7

General Character of Decade 1893-1903 .... 200
Advantage of Local (Provincial) Name ....00.22....22..222::tese-esceeeeeeeeeeeeee 201
Period of 1904 to. the Present (1912) ..w.......eeseeeeceeeteeeeeeeeeceeeeceeenteeeeeneese 201
Opening: of the Period) ......:..-2.cecceeccest se seseesecaeeescns neeseee ee 201
Salinas Valley—Hamnlin, 1904: 2.2.22... seccceceececcceccecceeeceseceeceeeeeees 202
San Luis Quadrangle—Fairbanks, 1904 0.2... eeeeeeeeeeeee eee 202
San Mateo County—Haehl and Arnold, 1904 20.00... 203
The Formation-Faunal Stage Fallacy ..........2...2-.::::eseceeeeereeeeeeeeeee 204
San Pablo and General—Merriam, 1904: _..0.2220..2..e22seefeeeeeeeeeeeeeeees 205
Depositional and Mauna Wacies: 22.i--cec- ese cescccerecesee tee ee 205
Mauna: ZOOS: 2...2-:-.s0sc5ete-sete-2-3-0ce-cseueteen sheer tates
Southern Coast Ranges—F. M. Anderson, 1904 —..........0.2022.2222------
Coalinga Region—F.. M. Anderson, 1905 -........2....:..-:-eeseeeeeeeceeoee
California Formations and Faunas—Arnold, 1906
Santa Clara Valley Oil Fields—Eldridge and Arnold, 1907 ........ 209
Puente: Hills—“Hildiritdie;, 90 sce. cesee cece cece cececeeeecace erase ee 210
Joos; Ampeles— Arnolds) VO Fierce seccercesececcece rece -seese sate nares ee ae 211
Sumerland District—Amm old) 907 oie cece eeccecs ee eaeeee eee ee 212
Santa Maria District—Arnold and Robert Anderson, 1907 .......... 212
Coalinga-McKittrick Region—F, M. Anderson, 1908 .................. 214
Geological History of Coast Ranges—Lawson, 1908 ...................- 215
Santa Cruz Folio—Branner, Newsom, Arnold, 1909 _...........-....... 216
Environment of Tertiary Faunas—Arnold, 1909 -...0022022.....-.----- 219
Coalinga Oil District—Arnold and R. Anderson, 1910 ~............... 219
Cantua-Panoche Region—R. Anderson, 1910 -..0......2..2.:--:2-:eeeee0-++ 220
McKittrick-Sunset Region—Arnold and Johnson, 1910 .............. 221
Geologie Record of California—J. P. Smith, 1910 —.00...202...022....... 222
Sargent Oil Wield—Jomes; WOM) —e cee cece eee eee eee 223
Kern River Region—F. M. Anderson, 1911 .....2......2-..:ce:sesecceeeeeeees 224
“femblor Basie’? cc. scce0 eee cececs se ceec ce iene ee OO)
South End San Joaquin Valley—-R. Anderson, 1912 .......0........... 228
Miocene Invertebrate Fossils—J. P. Smith, 1912 200000 .. 229
San Jose and Mt. Hamilton Quadrangles—Templeton, 1912 ...... 231
Kirker Pass—Clark,. W902) 2.1.00. 2a en eee 232
Pant Vl.—General Conclusions) 2 ose ce ee cece 232
General Description of Monterey Series ..............---.:--:ceeececereeeeecereseee 232
Monterey Sediments. ....:::.:ces-:cseeeeccessess-seeseeeeestes ee
General Distribution ...2.... ee

Progress of Sedimentation
Effect of Geographical Conditions

Depositional! @scullatvoms sre eeseeeee-ceeeeees sees cee p
Cert. 25:2.
Relation to the Occurrence of Petroleum ~.........022...22.2.:2:ee 236
Voleanic Products in the Monterey Series -..............-0.--.---ceesce- 236
Tullis |... i Oe 236
DiaiValS! . séccc2s0. nic beediteeciee et eee 237
iuimits: of the Series’ ........2:520 3 ee 237
Palaeontologie Characters: 2202222222. cesccscse.-sstese ees 238
FOAMM, access csecceesseececssshseeten eeveees ee eee 238
Faunal’ (Stages: .....c2. Assen see eee 239

Summary Statement of Various Other Conclusions ...........0.....2..2-2.-.- 240

1913] Louderback: The Monterey Series 179

PART I

THE SANTA CLARA VALLEY REGION OF VENTURA
COUNTY AND ITS RELATIONSHIP TO THE
COASTAL REGION TO THE NORTH
AND WEST?

INTRODUCTION

In the southern coastal region of California the Tertiary
formations are extensively developed and present many problems
of geological interest. Furthermore, on account of the remark-
able development of their petroleum contents that has taken
place in recent years, they have assumed a marked economic
interest. An understanding of the general relationships, corre-
spondenees, and correlations of the rocks of the various districts
into which the region may be divided is therefore of importance
to the student of any of the various problems involving these
formations.

As one after another of the West Coast Tertiary formations
has been more carefully studied there has gradually arisen what
may be looked upon as a standard depositional series applicable
to this coastal province, to which the formations in the more
newly studied localities are naturally compared and referred.

During the summer of 1910 the writer had the opportunity
of studying the oil fields of Ventura and Los Angeles counties
and of comparing the formations there associated with the oil
with those of similar associations further north. In the reports
of the Geological Survey on these districts,? one formation name
previously used and originally applied in the central Coast
Ranges is found applied to the local Tertiary, but the associated
formations, both above and below, are all given new names—

1 Presented before the Cordilleran Section, Geological Society of Amer-
ica, at the Berkeley meeting, April 1, 1911.

2 Eldridge and Arnold, Bull. 309, U. S. Geol. Surv., 1907.

180 University of California Publications in Geology [VoL.7

Modelo, Puente, Sespe, Topatopa,—presumably to emphasize
their lack of correspondence with established formation groups,
or the marked dissimilarity of the conditions under which they
were formed. For, besides using one of the ‘‘standard’’ names,
one of the authors of the bulletin presents a ‘‘Standard Cali-
fornia Section’’ (p. 143) and makes comparisons with it. Fur-
thermore, in the descriptions of the formations, special attention
is called to the dissimilarity even between formations as close
together as the two sides of the Santa Clara Valley, and the
difficulty of correlating or even of using the same formation
names for the two areas is pointed out and discussed (e.g., p. 21).

It was therefore with considerable interest that the writer’
entered the southern field to get a better understanding of those
conditions which produced there a different province of depo-
sition from that of the country north of Santa Barbara. It
must be admitted that the descriptions in the bulletin of the
various stratigraphic members gave hints of some striking simi-
larities between the Santa Clara region and the central Coast
Range region, but in several ways the order of events and the
major divisions appeared to show abnormalities that required
explanation.

Infortunately opportunity was not given to make careful
detailed studies of contacts or sections such as are necessary for
an accurate understanding of the details of formational rela-
tionships. However, some of the more general features appeared
to indicate so definitely the general relationships that it is be-
lieved a statement of them will aid in a better understanding
of an important period of sedimentation.

PREVIOUSLY DESCRIBED SECTION NortTH OF SANTA CLARA VALLEY

The most complete Tertiary section of the southern California
region that has been described is that found to the north of the
Santa Clara Valley in Ventura County, commencing with the
Topatopa range anticlinal axis and running southeastward to-
wards the valley. The following section has been prepared from
the descriptions in Bulletin 309, plate 1 of which may be con-
sulted for the areal distribution of the formations:

1913]

Louderback: The Monterey Series 181

GEOLOGIC COLUMN

For Formations NortH or SANTA CLARA VALLEY, VENTURA COUNTY
(ACCORDING TO DESCRIPTIONS IN BuLL. 309, U. S. G. S.)

Fernando
Formation
(Pleistocene
to upper
Miocene)

Modelo
Formation

(middle
Miocene)

Vaqueros
Formation

(lower
Miocene)

Sespe
Formation
(Eocene)

Topatopa
Formation
(Eocene)

Granite

Upper shale,
200-1500 ft.

maximum 900 ft.

Conglomerate, sandstone, and arenac-
eous clay

UNCONFORMITY
Granular, siliceous to earthy, fissile
shale, brown, gray, or yellowish;
| carrying caleareous layers and len-

ticular limestone concretions

slightly yellow by iron; much dark

Upper sandstone, [seh of white subangular quartz,

Lower shale,
400-1600 ft.

Lower sandstone,

200-2000 ft.

500-600 ft.

About 700 ft.

500 ft.

About 500 ft.

Upper Sespe,

500 ft.

Middle Sespe

(Red beds),
1240-1800 ft

Lower Sespe,

chert in fragments also present
Indistinguishable lithologically from
{ upper shale
lesen heavy bedded, white to yel-
lowish gray, locally gritty with
pebbles of dark chert and sand-
stone; scattered yellow weathering
limestone concretions, often stained
dark by petroleum; concretions 1-5
ft. in diameter, very characteristic

eee

Siliceous shale and limestone, gray
but yellow weathering, indistin-

1 guishable lithologically and faunally
from Modelo shale

Deep maroon, brown and gray shale

Gray shale

Chiefly shale with limestone lentils

calcareous sandstone separated by
bands of shale

Sandstone and shale, occasionally con-
glomerate; 400-800 ft.

Heavy sandstone often coarse and
gritty with thin shale beds, occa-
sionally conglomerate; 500 ft.

Massive sandstone, occasionally con-
glomerate; 300-400 ft.

Coarse conglomerate; 40-100 ft.

te cai sandstone and green and pink

pre (ochreous) to greenish gray,

400 ft. elays and shale
Hard submassive sandstone and
quartzite, greenish gray, clear or
5500 ft. exposed mottled with white, and shale;
sandstones usually light gray to
white
UNCON FORMITY

182 University of California Publications in Geology [Vou.7

VaAQUEROS-MONTEREY SERIES OF MONTEREY-SANTA BARBARA

COASTAL REGION

As developed in Santa Barbara County not many miles
directly west of the Santa Clara Valley locality, and in San
Luis Obispo and Monterey counties to the north, the Vaqueros
deposition commences characteristically as a greenish gray to
rusty yellow, or whitish, sandstone, with here and there pebbly
or conglomeratic layers, especially near the base. As we pass
higher into the series terrigenous shales become the dominant
type, and finally siliceous (diatomaceous) shales so characteristic
of the ‘‘Monterey’’. Fairbanks*® places the base of the Monterey
in the San Luis quadrangle at the base of the clay shale above.
the zone of dominant sandstones. Arnold in the Santa Maria‘
and the Summerland’ districts in Santa Barbara County places
the zone of dominant terrigenous shales in the Vaqueros, and
considers that the siliceous, biogenic shales usher in the Monterey.
Both consider that the Vaqueros and the Monterey form a con-
formable series.

APPARENT CONTRASTS BETWEEN THE Two REGIONS

Without discussing at this point the relative merits of the
two systems of criteria, let us compare the general course of
events as shown by the Vaqueros-Monterey period of sedimen-
tation along the coast from Monterey to Summerland, a distance
of about 200 miles, with the series described by Eldridge and
Arnold for the region north of Santa Clara Valley, 20 miles or
less east of Summerland.

We note in the latter that the Vaqueros deposition is inaug-
urated as a shale, passes into siliceous shale and then the Modelo
follows conformably as thick sandstone followed by siliceous
shale, then more sandstone and more siliceous shale. The Modelo
is correlated with the Monterey by Arnold.®

3 10s

5U.

6U.

™M

. Geol. Surv., folio 101, San Luis, California, 1904, p. 4.
. Geol. Surv. Bull. 322, 1907.

. Geol. Surv. Bull. 321, 1907.

. Geol. Surv. Bull. 309, 1907, p. 143.

DMM

1913] Louderback: The Monterey Series 183

The Santa Clara district would then appear to be exceptional
in (1) the opening of Vaqueros sedimentation, (2) its closing
phases, and (3) the opening of the supposed correlative of the
Monterey, the Modelo. As products of deposition are so
abundant here, and as the district is so close to the edge of the
Monterey-SanLuis Obispo-Santa Barbara region, these excep-
tional features naturally call for further explanation.

THE OPENING OF THE ‘‘ VAQUEROS’’ DEPOSITION

In examining the Santa Clara region formations in the field,
the writer was continually met by the fact that at the base of
the shales called Vaqueros there lies everywhere a sandstone,
usually several hundred feet thick, with conformable relation-
ship to the shales, which corresponds closely in general nature
and appearance to that found at the base of the clay shales else-
where, in other words, to the normal opening stage of Vaqueros-
Monterey deposition. It has the lthologic character and strati-
graphic position of the sandstones to which Fairbanks in the
San Luis region would restrict the term Vaqueros. But Eld-
ridge and Arnold have separated it from the Vaqueros and
grouped it with another formation—the Sespe, calling it the
upper Sespe (Eocene or Oligocene).

A careful study of the Santa Clara bulletin has been made
by the writer to learn if possible why these sands were separated
from the Vaqueros and united with the Sespe, but without results.
According to this report,’ under the heading ‘‘ Relation of Upper
Sespe Beds to Vaqueros Shale,’’ ‘‘No sharp lines of distinetion
separate the upper Sespe terrane from the underlying red beds
or the overlying Vaqueros. On the contrary, there is a pereept-
ible tendency for the terranes to shade one into another. Fossils
of value have not yet been collected from this transitional zone.
There is, therefore, some uncertainty as to whether the beds in
question should be referred to the Eocene or the Miocene. .. .
Tentatively, however, the ine between the Sespe (Eocene) and
the Vaqueros (lower Miocene) formations has been drawn at an
indefinite horizon in the rusty beds described, at a point where

7U.S. Geol. Surv. Bull. 309, pp. 11 and 12 (1907).

184 University of California Publications in Geology (Vou. 7

sandstone no longer predominates but is largely replaced by shale,
vet below the lowermost lower Miocene fossils found.’’

With such a lack of a definite division plane between shales
and sandstones, or rather such a gradation between them, the
only logical procedure would seem to be to construct the series
on the plan of its nearby, definitely determined and lithologically
similar correlative.

lurther evidence of this relationship was obtained by an
examination of the ‘‘Upper Sespe’’ for palaeontological data.
At various horizons fossils were found, although mostly in a
broken condition and not distinctly determinable. About fifty
feet above the base of the ‘‘Upper Sespe’’ in the hills to the
south of Tar Creek, where this formation is about 500 feet thick
and is mapped® as a strip one-half to three-quarters of a mile
wide, a layer was found made up practically entirely of one
species, Scutella fairbanksi Merriam,® which is considered a
characteristic fossil of the Vaqueros zone.

There seems, therefore, no reason for hesitating to disconnect
these sands from the Sespe group and unite them definitely with
the Vaqueros-Monterey. The exceptional nature of the opening
of this period of sedimentation in the Santa Clara region there-
fore disappears.

Tue SESPE FORMATION

‘The term Sespe was originally used by Watts’? in the form

‘‘Sespe brownstone formation,’’ which he said ‘‘consists of sand-
stone shales and conglomerate all being more or less brown in
eolov.’? Eldridge and Arnold'! employed this term in the ex-
pression ‘‘Sespe formation,’’ as shown in the columnar section
above given and added to the brownstone formation the yellowish
(ochreous) sandstones above and a white sandstone below.

The exact relationship of the Sespe brownstone formation
to the Vaqueros the writer did not work out. In a general way

8 Bull. 309, Plate I.

9 This determination was kindly checked by Professor J. C. Merriam.

10 Bull. Cal. State Mining Bureau, no. 11, pp. 11 and 12.
11 U. S. Geol. Surv. Bull. 309, pp. 7-12.

1913] Louderback: The Monterey Series 185

in the Sespe region it underlies the latter with the same attitude,
—that is, apparently conformably, but that relationship is subject
to doubt.

At the least, the local representative of the Vaqueros as

redelimited to include the so-called ‘‘upper Sespe’’ shows a
sudden and permanent change in the type of sedimentation from
that of the ‘‘brownstone’’ or ‘‘red beds,’’ so that even with a
conformable relation there is a natural line of demarcation be-
tween them, and a special name will probably always be desirable
for the red beds, even if they are included within the series above
or below them. :

This brownstone series is a rather local phenomenon. It
runs west a few miles into the Santa Barbara region, but as far
as known is not found to the north of the Santa Ynez river.
Its extent east and south is also rather limited. It appears to
be confined to a territory including southern Santa Barbara and
Ventura counties and possibly part of Los Angeles County.
Passing beyond the limits of this region the Vaqueros retains
its yeneral features, but the Sespe has disappeared, and as far
as now known nothing just like it is found elsewhere in Cali-
fornia.”

These relationships would at least suggest that the Sespe
brownstone formation is not a member of the Vaqueros-Monterey
series, and may be separated from it by a time break or uncon-
formity. At the April, 1912, meeting of the Cordilleran Section
of the Geological Society of America, Mr. Robert Moran reported
the unconformable relationship of the Vaqueros and Sespe in
the restricted sense as delimited above, as seen in southern Ven-
tura County, and in the writer’s opinion the mapping of these
groups and the relationships of the Vaqueros-Monterey voleanies
to the Sespe in the Semi region appear to offer good evidence to
support this view.

No special reason has been put forward for attaching the
white sandstones below the brownstone formation to the Sespe

12 The writer has seen beds that suggest the Sespe type of deposition
on the hills to the west of the Carrizo plains, but their stratigraphic rela-
tionships were not determined. The reddish to purplish shales above the

fossiliferous Tejon sandstones in the Mt. Diablo range may be a corre-
sponding facies of deposition.

186 University of California Publications in Geology [VoL 7

in preference to the Topatopa, and it would seem that here, too,
unless a good reason for a different arrangement were forth-
coming, the line should be drawn where the distinct and charac-
teristic change in sedimentation takes place,—that is, at the base
of the red beds.

This idea is strengthened when the present state of our knowl-
edge of the fauna of these formations is taken into account.
Fossils are very rare in the ‘‘red beds,’’—in fact, have not yet
been reported in any of the red or reddish brown colored strata.
Elridge and Arnold report'® that ‘‘In Sespe Canyon fragments
of vrayish-yellow sandstone, coming either from some horizon
unrecognized but well up in the red beds or from a_ horizon
corresponding to that of the rusty beds just deseribed, have
been found bearing well marked Eocene fossils among which
are the forms Venericardia planicosta Lamarck and Turritella
uvasana Conrad. Beds of a similar nature, with an abundance
of Tejon (Eocene) fossils, also occur along the northern edge
of the Silver Thread oil field, west of Santa Paula Cayon, over-
lying certain pink and gray sandstones that are believed, on
lithologie grounds, to belong to the Sespe.’’ The list of fossils
given includes at least nine characteristic Tejon forms found
at the type locality. The available evidence is to the effect,
therefore, that the Sespe is a phase of the Tejon (Eocene). If
this be so, then the Topatopa and Sespe are two local deposi-
tional facies of the Tejon. It seems peculiar that with the type
locality for the Tejon only 20 or 25 miles away, and with a good
supply of characteristic Tejon fossils, the term Tejon was not
used for the rocks of this district.

‘ ’

Upper Part or ‘‘ VAQUEROS-MODELO’’ SERIES

Region North of Santa Clara Valley.—If{ we pass up from
our newly established base of the Vaqueros (‘‘upper Sespe’’)
and compare the depositional types with those of the correspond-
ing series along the Monterey-San Luis Obispo-Santa Barbara
coast region, we find the sandstone, 500 feet, which would cor-
respond to Fairbanks’ Vaqueros, followed by dominant terrig-

13 Bull. 309, p. 11.

1913 ] Louderback: The Monterey Series 187

enous shales which corespond to his lower Monterey shales in
the San Luis area, or Arnold’s upper Vaqueros shales in the
Santa Maria district, then siliceous (diatomaceous) shales corre-
sponding to the siliceous shales generally recognized throughout
the Monterey-San Luis Obispo-Santa Barbara region as Mon-
terey.

These siliceous, biogenic shales are separated in the region
north of Santa Clara Valley by a thick sandstone (Lower Modelo
sandstone), from other siliceous shales above, and these by an-
other sandstone (Upper Modelo sandstone) from a third body
of siliceous shale still higher. Of this last shale, it is said:"*
‘‘This shale is indistinguishable from that separating the two
Modelo sandstones already described. . . . Were the upper sand-
stone to disappear, the shales above and below would become a
single mass, uniform in their general features from top to bot-
tom;1®> were both sandstones to disappear it would be difficult
to distinguish these rocks from the upper portion of the Vaqueros
formation.’’ In other words, were the two sandstones not
present, the upper part of the series would become a uniform
succession of siliceous diatomaceous shales and correspond in
character and stratigraphic position exactly with the siliceous
Monterey shales of the coast region to the west and north.

The Modelo Sandstones—A study of the rield relations'® of
these sandstones leads to suggestive results. In upper Hopper
Canon the lower Modelo sandstone is well developed and _ is
probably over 2000 feet thick. This thickness diminishes rap-
idly towards the south, so that in 5 or 6 miles it is only a few
hundred feet and within 8 or 9 miles it has apparently disap-
peared or is so insignificant as to attract no attention. No for-
mation corresponding to it has been recognized south of the
Santa Clara Valley, nor to the west in the Sulphur Mountain
district.

The upper sandstone has not been recognized over so large
an area, nor is its maximum thickness so great nor its tapering
so rapid, but its relationships seem to be similar. It les in

14 Bull. 309, p. 19.

15 The italics introduced by present writer.

16 These descriptions may be followed on map, plate I, Bull. 309, U. 8.
Geol. Surv.

188 University of California Publications in Geology [Vou.7

the same general territory as the lower sandstone—that is, east
of Sespe Creek, north of Santa Clara Valley, and does not cross
the Piru drainage basin to the east. It appears to die out before
the south side of the Santa Clara Valley is reached.

These sands, then, are strictly local facies which grow thicker
as they approach the mountain mass to the north. from which
they were probably derived; and to the west, south, and southeast
(to the east they pass under later formations and their extent
is unknown) they thin down either to negligibly small layers or
to complete extinction.

Region South of Santa Clara Valley.—To the south of Santa
Clara Valley, the development of the Vaqueros-Monterey series
is simpler and the correspondence with the normal coast type
more readily discernible. Fossils are abundant in the lower
layers, so that the horizon is readily identified. The whole series
is thinner, in particular by loss of the Modelo sandstones and
a considerable decrease in the terrigenous shales. It may be
noted that these shales show variation in thickness on the north
side of Santa Clara Valley similar to that shown by the Modelo
sandstones,—that is, they decrease in thickness towards the south,
west, and southeast, although they do not, as far as observed,
entirely disappear.

There appears to be no reason to doubt that the formations
south of the Santa Clara Valley represent as a whole practically
the same duration of deposition as do those to the north, and
that the particular differences of the latter are due simply to
an original position nearer inshore, during at least a large portion
of the period, and more directly related to a special source of
supply of terrigenous detritus—the mountainous region of north-
ern Ventura County. This relationship was indeed suggested
as a possibility by Eldridge and Arnold:* ‘‘South of the river
this division does not appear to hold, yet one or another of the
characteristics of the Miocene, taken as a whole, north of the
river reappears on the south side, suggesting that the beds on both
sides of the valley from base to summit should be included in a

single formation.”’

17 Bull. 309, p. 21.

1913 ] Louderback: The Monterey Series 189

Results—Krom the above considerations it is evident that
the division of the series at the base of the lower Modelo sand-
stone is an artificial division which holds in only a small part
of the Santa Clara field, and that the line as drawn to the west
of Sespe Creek and south of Santa Clara river is the same as
that used by Arnold in the Santa Maria district,—that is, the
base of the siliceous shales.

LiItHOLOGICAL TYPES AND NOMENCLATURE IN VARIOUS FIELDS

t should be particularly noted that the distinction between
Vaqueros and Monterey or Modelo has been actually made in
the field by Hamlin,'* Fairbanks, Eldridge, and Arnold, in the
Salinas Valley, San Luis quadrangle, Santa Maria district, Sum-
merland district, and Santa Clara Valley districts, on a strictly
lithologic basis,—that is, on a change in the type of sedimen-
tation, and we may represent the correlation of depositional
types in these districts by the following table in order to show
how the application of the nomenclature and the position of
the divisional lines have varied.'®

18U. S. G. 8S. Water Supply and Irrig. Paper no. 89, 1904.

19 It is evident that the questions here considered have nothing to do
with the determinations of horizons as indicated by faunal zones within
the Vaqueros-Monterey Series.

[ VoL. 7

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1913] Louderback: The Monterey Series 191

RELATIONSHIPS OF DIFFERENT SECTIONS OF THE SERIES

The foregoing table is a comparison of the general features
of several sections of the Monterey-Vaqueros series, the division
lines being drawn on a lithological basis—the only basis on
which actual divisional lines have been drawn in the areas repre-
sented. But a careful comparison of different sections of the
Santa Clara Valley region gives very suggestive evidence, as
explained above, that much of the terrigenous shale in the Sespe
district corresponds to diatomaceous shale south of the Santa
Clara Valley, and that much of the Modelo sandstones corre-
sponds to contemporaneous deposition of siliceous shales south
of the valley.

A study of numerous sections along the coast to the north of
Point Conception has led the writer to similar conclusions for
other areas. In the Santa Maria district conglomerate at one
point is seen to take the place of sandstone within a few miles
(as in the region between Suey Creek and Huasna- Creek) ;
sandstone at one point is replaced by terrigenous shales within
a moderate distance (as in the Casmalia Hills). The rapid flue-
tuation in thickness of the terrigenous basal members of the
conformable series which grade into biogenie caleareous and
then siliceous shales, the terrigenous members retaining the same
faunal facies, indicates that the terrigenous material at one local-
ity is strictly contemporaneous with detrital material of a dif-
ferent grain and with biogenic material at others. This rela-
tionship is suggested practically everywhere that the series is
developed.

In particular, it is frequently observable that the terrigenous
material is definitely related to older land masses in many local-
ities, and that the biogenic shale increases in amount in definite
directions—often in directions that point to greater distance
from an old shore line, as was brought out for the Santa Clar:
region and will be indicated for several other localities in a later
part of this paper.

192 University of California Publications in Geology [Vou.7

CONCLUSION

It results from these relationships that in the region observed
the ‘‘Vaqueros’’ is merely a depositional facies, as is also the
‘“Monterey shale,’’? the former type including the lower sand-
stone and conglomerate and intercalated shale, according to the
usage of Fairbanks and Hamlin, the latter the predominant clay
shales, limestone and diatomaceous beds. Eldridge, Arnold, and
R. Anderson throw the usually intermediate strata—predomi-
nately terrigenous shale and limestone—into the Vaqueros type.
In the territory mapped by Fairbanks (San Luis Folio) we
must hold that Vaqueros sandstone of one portion corresponds
to Monterey shale of an adjoining portion, and the same holds
in the Santa Clara district mapped by Eldridge and the Santa
Maria district mapped by Arnold, Anderson, and Johnson.

The use of these terms as ‘‘formations’’ representing definite
time intervals is misleading and gives a wrong picture of this
great depositional series as a whole. The correlations usually
put forward are merely formal and not real. Stratigraphically
the one thing we can generally recognize definitely is the series,
the lower portion of which, from several feet to several thousand
feet, is usually terrigenous and is distinguished from underlying
beds, either by unconformity, distinctive fauna, or marked change
in depositional type. It was brought to a close by an uncon-
formity representing important orogenic movements throughout
the whole California coastal region, or at least throughout the
whole region in which its deposition had taken place. It repre-
sents, in facet, a depositional eyele, and emphasis should be placed
on the series as a whole, and a single name should be- used to
designate it. It represents historically, areally, and economically
one of the important periods of deposition in West Coast geologic
history, and to be appreciated it should be presented as a major
stratigraphic unit—which it is. Its most important relation-
ships and essential characteristics are lost when it is presented
merely as two or more different ‘‘formations.’? The name
‘Monterey Series’’ was proposed some years ago*® by Lawson,

20 Univ. of Calif. Bull. Dept. Geol., vol. I, pp. 1-59 (1898).

1913 | Louderback: The Monterey Series 193

and has been used by him and some others consistently ever
since for the rocks of this depositional cycle. It will be used in
this paper in the further discussion of the subject.

The Vaqueros sandstone, the Monterey shale, the Modelo sand-
stone, are mere depositional facies, and while rocks designated
by any of these names may be analogous in different localities,
they are frequently not correlative. The ‘‘Modelo formation’’
is an artificial and, as far as evidence goes, meaningless group,
not even applicable throughout the region of the Santa Clara
Valley oil fields and it should be abandoned.

PART II

CRITICAL REVIEW OF OUR KNOWLEDGE OF THE
MONTEREY SERIES IN CALIFORNIA AND

HISTORY OF ITS NOMENCLATURE

PURPOSES

In the light of the ideas developed in Part I of this paper,
it is proposed to review critically the literature that has had
most influence on present day conceptions of the California
Middle Tertiary, with the purpose (1) of determining if pos-
sible the extent to which these ideas will apply to other areas;
(2) of eritically examining the evidence presented for various
other interpretations and the bases for the diverse nomenclature ;
(3) of bringing out the main characteristics of the Monterey
series in the different areas in which it has been studied.

EARLY NOTICES—PREVIOUS TO 1893
Probably the first reference that occurs in the hterature to
the most peculiar member of this series is in an article by W. P.
Blake, published*! in 1855 and entitled ‘‘Notice of Remarkable
Strata containing the remains of Infusoria and Polythalamia in
the Tertiary Formation of Monterey, California.
quently referred to as the paper in which the formational name

te)

This is fre-

21 Proce. Acad. Sei., Philadelphia, vol. 7, pp. 328-331 (1855).

194 University of California Publications in Geology |Vou.7

‘*Monterey’’ was first definitely given and defined. It is a his-
torically interesting paper in that it is the first notice of that
type of deposit that is so widespread and important, both geolog-
ically and economically, in California—the siliceous, chiefly dia-
tomaceous, earths and shales. A careful reading, however, shows
no intention to either name or define any stratigraphic unit,—
the whole purpose was to announce the occurrence in thick de-
posit of this remarkable type of strata. A partial section is
given, the lowest member of which was not estimated as ‘‘it
extends downward under the chamisal for a lone distanee.’’

‘“This interesting formation, teemine with the skeletons of
microscopie organisms, appears to overlie and to be conformable
with the tertiary strata that underlie a part of the town of
Monterey and extend to and beyond the Mission of San Carlos.
These strata rest upon a porphyritie granite’’ (p. 330). These
latter strata are said to contain fossil shells, the more abundant
of which Conrad described and named Tellina congesta, which
at San Carlos is associated with Lutraria Traskii, also a new
species.

“A stratum of the Monterey formation similar in texture
to the stone which is used for buildings, but different in color,
also contains casts of Tellina congesta in great numbers’’
(p. 331). This is the only mention Blake makes of ‘‘Monterey
formation,’’ or any similar expression, and it is evident from
the context that he was not naming a stratigraphie unit, but
simply meant the formation or type of material at Monterey—
a mere locality designation—a common practice among the geolo-
gists who explored the west at that period and for 20 or more
years later.

As further evidence of this, it may be noted that Blake pub-
lished two geological descriptions of the territory about Monterey
the iollowing year (1856), without once mentioning these rocks
by such a designation. In the Pacific Railroad Report,*? he
described them as ‘‘the Tertiary formations,’’ and uses the term
Monterey only in the following expressions, ‘‘the base of the
formation at Monterey,’’ ‘‘A stratum of the Monterey rock’’

22 Reports of Explorations and Surveys to ascertain the most practi-

cable and economical route for a railroad from the Mississippi River to the
-acific Ocean. Vol. 5 (1856), Part II, Chapter XIII, esp. pp. 180-182.

1913 | Louderback: The Monterey Series 195

(p. 180). In the Report of the Superintendent of the Coast
Survey,° they are again called ‘‘ Tertiary Strata’’ (p. 391), and
Monterey is only used in the expression ‘‘strata about Monte-
rey.’’ In Map no. 59, the formations in the ‘*‘ Vicinity of Mon-
terey Bay’’ are plotted, and the strata under discussion are
mapped as ‘‘Tertiary,’’ not as ‘‘ Monterey shale’’ or other similar
designation, although in Map no. 58, of San Francisco harbor,
the ‘‘San Francisco Sandstone”’ is so designated and ‘‘Tertiary”’
written after it. This is really not a very important point, and
would not here be discussed were it not that in several publi-
cations of the U. 8. Geological Survey** it is distinctly stated
that the ‘‘Monterey formation’’ (as a stratigraphic unit) was
named and deseribed in the paper above referred to.

These formations were also referred to or deseribed by other
early geologists, such as Trask,?? Whitney,°® and Becker,*’ who
generally referred to their most characteristic type as bituminous
“*slates.’’

DECADE 1893-1903: RECOGNITION OF SERIES AS STRATIGRAPHIC
UNIT AND EXTENSION OF KNOWLEDGE OF ITS
AREAL DISTRIBUTION

Carmelo Bay, Lawson, 1895.—The first definite application of
a local name to the series as a stratigraphic unit was made by
A. © Lawson in ‘‘The Geology of Carmelo Bay,’’ published in
1893.28 ‘‘The Miocene formations are abundantly developed .. .
The series was among the first which attracted the attention of
the earlier writers, Trask and Blake, and it has since become
famous for the ‘infusorial’ remains which it contains, being
known to collectors as the Monterey formation.*? This name,

23 Report of the Superintendent of the Coast Survey showing the pro-
gress of the Survey during the year 1855 (1856), Appendix no. 65, pp.
390-392.

24 Bull. 191 (1902), Prof. Paper 47 (1906), Bull. 321 (1907), Bull. 522
(1907).

25 Report on the Geology of the Coast Mountains, ete. Assembly Jour-
nal, 5th Session, 1854, Legislature, State of California, Appendix, doc. no.
9; 6th Session, 1856, Appendix, doe. 14.

26 California Geological Survey, Geology, vol. I (1865).

27 U. S. Geol. Surv., Bull. no. 19 (1885); Monograph 18, p. 185 (1888).

28 Bull. Dept. Geol. Univ. of Calif., vol. 1, pp. 1-59 (1893).

29 In the meaning given by collectors and prospectors, formation means
any type of deposit or produet—really a rough petrographical term, as
‘“stalactite formation,’’ ‘‘lime formation.’’

196 University of California Publications in Geology (Vou. 7

under the form of the ‘Monterey series’ will be adopted as the
local designation of the series’’ (p. 7).

That by “‘local designation’’ he meant to inelude the whole
depositional province, is shown by the statement: ‘‘The rocks
of the Monterey series, as displayed in the vicinity of Carmelo
Bay, are representative of the Miocene wherever it occurs for
several hundred miles along the coast of California’’ (p. 22).
A rather full description and discussion of the origin and rela-
tionship of the series follows, and it is plotted on the map of
Carmelo Bay, Plate I, as the ‘‘ Monterey Series (Miocene).’’

That it was not intended to so designate merely a lithologie
type is indicated by the following: ‘‘ Near the base of the series
at the town of Monterey there are some sandstones. There are
also occasional lenses of a dense yellowish to mauve-colored fos-
siliferous limestone, and... there are some beds which are
both caleareous and gritty’’ (p. 24). Voleanie ash is also
described in the series.

A list of fossils is given as determined by Dall, in addition
to those reported by Blake, and the conclusion reached that the
series 1s Miocene.

Point Sal, Fairbanks, 1896.—In 1896, Fairbanks®® described
representatives of this series from Point Sal under the desig-
nation ‘‘Miocene.’’ He notes 1000 feet of ‘‘bituminous shales’’
earrying Pecten peckhami Gabb, including limestone, caleareous
sandstone, marly rocks and flints, below which are ‘‘gypsiferous
clays’’ 1800 feet, three strata of ash, and finally 2000 feet of soft
sandstone, shale, and conglomerate.

Santa Catalina Island, W. S. T. Smith, 1897.—In 1897 W.S.
T. Smith deseribed*! diatomaceous Miocene shale, voleanic tuff
and limestone on Santa Catalina Island, associated with Tellina
congesta, Conrad. The diatom remains were discussed by G. J.
Hinde.

San Clemente Island, W. 8S. T. Smith, 1898.—In 1898 he de-
scribed ‘‘Miocene’’ beds on San Clemente Island,*? beginning as
sandstones and passing into yellowish to grayish white shales,

30 Bull. Dept. of Geol. Univ. Calif., vol. 2; see pp. 9-18 (1896).

31 Proe. Calif. Acad. Sci., 8rd Ser. Geology, vol. 1, no. 1 (1897).
32 U. S. Geol. Surv., 18th Annual Rept., 465-496 (1898).

1913] Louderback: The Monterey Series OT

the bulk of which consists of diatoms, associated with radiolaria
and foraminifera, and showing abundant impressions of Pecten
peckhami Gabb.

Southern Coast Ranges, Fairbanks, 1898.—In the same year,
Fairbanks published a general account of the Geology of the
Southern Coast Ranges,** particularly in the vicinity of San
Luis Obispo, in which he describes the ‘‘ Monterey series (Lower
Miocene). With the beginning of the Neocene a subsidence
commenced and continued through, or nearly through the Mio-
cene. Finally, almost the whole Coast Range region was sub-
merged and a thickness of rocks in many places of more than
7000 feet was deposited. The most characteristic feature of
the series is the bituminous shales. They form its upper portion
and reach a thickness of 5000 feet. Below them are limestones,
clays, voleanie ash, sandstones, and conglomerates. .. . The
sandstones and conglomerates at the bottom of the series are
most prominently developed in the region lying east of the Rin-
conada Valley, between it and the main granite range’’ (p. 561).

Point Reyes Peninsula, F. M. Anderson, 1899.—In a paper
on the geology of the Point Reyes** Peninsula, 1899, F. M.
Anderson describes the there developed representative of this
period of deposition under the head of ‘‘ Miocene Sediments,’’
consisting of conglomerates up to 300 feet thick, resting on the _
granite, and occasionally very coarse, followed everywhere by
hight yellowish sandstones and then whitish, thin bedded siliceous
shale. The latter is said to be the ‘‘white Miocene shale of the
Monterey series, well known in the Coast Ranges.’’ On the
Point Reyes peninsula ‘‘The series is entirely conformable, and
doubtless all belongs to the same period of sedimentation. ”’

Coast Range Bituminous Rock Districts, Eldridge, 1901.—In
1901 (or 1902) Eldridge published a general survey of ‘‘the
Asphalt and Bituminous Rock Deposits of the United States’’*? in
which the Monterey rocks of California were given the following
general description.

33 Jour. of Geol., vol. 6 (1898), this series described pp. 561-563.

34 Bull. Dept. Geol. Univ. Calif., vol. 2, pp. 119-153. Miocene, pp.
134-141.

25 U, S. Geol. Surv., 22d Annl. Rept., Part I, pp. 209-452. The main
points of this paper were presented later in Bull, 213, pp. 296-805, 1908.

198 University of California Publications in Geology [Vou.7

‘‘Lower Neocene (Monterey ).—The rocks of this age usually
embrace a heavy body of sandstones, conglomerates, and shales
at the base, in which the form Ostrea titan is often found; over-
lying these in some places is a body of gypsiferous clays that,
in the region of Point Sal, for example, attains a thickness of
nearly 2000 feet; above all is the salient feature of this series,
a great body of more or less siliceous shales, everywhere of con-
siderable thickness and locally embracing at least -2000 or 3000
feet. This suecession is not, however, strictly adhered to at all
points. The formation is distributed the entire length of the
Coast Range from Cape Mendocino to beyond Los Angeles. It
borders the coast and occurs in the interior, forming a conspic
uous terrane along the great valley of California drained by the
San Joaquin and Sacramento rivers.”’

A few of his local descriptions will be referred to. ‘*Mon-
terey shale’’ was described from the Santa Cruz district. ‘‘ For
the Coast Range, in general it has already been stated that the
lower portion of the Monterey frequently consists of sandstones.
The sands here referred to’’ (in local description) ‘‘may be the
equivalent of these; or, on the other hand, it may be that they
are simply a shore deposit of uncertain age laid down prior to
the deposit of the Monterey shale, and derived in large measure
from the adjoining granite or brought into their position by
coastwise currents’? (pp. 383, 384).

Vhe Monterey was also reported and briefly described from
the Salinas Valley region, San Luis Obispo district, the Santa
Maria district, Los Alamos district, the southern coastal strip
of Santa Barbara County, the Chino district (Puente Hills),
and the Asphalto district (MeKittrick). In many of these local-
ities it is said to lie unconformably below the ‘‘San Pablo (Middle

Neocene ) Sandstones are often reported as intercalated in
the shales, or at the base of the shales and either definitely or.
doubtfully referred to the Monterey.

Point Arena District—As Eldridge’s is the only published
account of the Point Arena district, it is presented here in more
detail than the other districts mentioned.

‘‘This district embraces a small area of Monterey shale lying

along the coast about 110 miles north of San Francisco. The

1913 | Louderback: The Monterey Series 199

shales form a low, rolling bench between ocean and Coast Range,
2 or 3 miles wide, and from 100 to 200 feet above the sea at the
shore to 300 or 400 at the base of the range proper. The bench
is cut transversely by streams from the mountains, and along
them the shales are well exposed, displaying several folds with
axes trending N. 50° W.”’

“The shales of the Monterey in this locality are interlami-
nated with sandstones varying in thickness from a foot or two
up to 30 or 40.—The shales are brown on fresh fracture, weath-
ering to a greenish-gray; they are also clearly bituminous, not
only for the locality in question but along the whole of this
portion of the coast’’ (p. 379).

derkeley Hills, Lawson and Palache, 1902.—In 1902, Lawson
and Palache published** the Geology of ‘‘The Berkeley Hills,’
in which is described ‘‘The Monterey Series,’’ resting uncon-
formably on the Chico (upper Cretaceous), and composed chiefly
of siliceous shales and cherts earrying Tellina congesta, Pecten
peckhami, fish scales and foraminifera. The series also is said
to contain sandstones and limestones, the former carrying unrec-
ognizable species of Tapes, Cytherea, Anthomya, Macoma, Lucina,
Tellina, and Neverita. Furthermore, ‘‘it should be observed that
this formation, as exposed on Skyline Ridge, does not represent
the entire Monterey series. The series in Contra Costa County,
only a few miles to the eastward, is made up of an alternation
of four fossiliferous sandstone formations and three formations
of ‘bituminous shale,’ aggregating in all several thousand feet
in thickness’’ (p. 367).

Middle Coast Ranges, Lawson, 1903.—This Contra Costa
County Section had been presented by Professor Lawson before
the Cordilleran Section of the Geological Society of America®’
in December, 1901, as follows:

Upper Stage 7, sandstone, 1800 ft.
Stage 6, bituminous shale, 670 ft.

Stage 5, sandstone, 1200 ft.

Monterey <~ Middle ~ Stage 4, bituminous shale, 1400 ft.
Stage 3, sandstone, 600 ft.

Stage 2, bituminous shale, 250 ft.
Lower Stage 1, sandstone, 400 ft.

86 Univ. Calif. Publ. Bull. Dept. Geol., vol. 2, see pp. 363-371.
37 Geological Section of the Middle Coast Ranges of California, Bull.
Geol. Soc. Am., vol. 18, pp. 544-545 (1903).

200 University of California Publications in Geology (Vou.7

San Pedro, Arnold, 1903.—In 1903, Ralph Arnold,** in ‘‘The
Palaeontology and Stratigraphy of the Marine Pliocene and
Pleistocene of San Pedro, California,’’ stated that ‘‘The oldest
formation exposed in the immediate vicinity of San Pedro is
the Miocene, or Monterey series. The shales of this formation
are exposed along the sea cliff in the eastern end of San Pedro
Hill and also on Deadman Island’’ (p. 12).

Petroleum Districts, Eldridge, 1903.—In Contributions to
Economie Geology for 1902,*° Eldridge gave an outline of the
geology of the various oil districts of California. He described
formations referable to the Monterey series in the following

localities: Coalinga (*‘100 or 200 feet of clays and sandstones

that may prove to be Lower Miocene; 200 feet of siliceous shales
typical of the Monterey (Upper Miocene) ’’) ; MeKittrick (‘‘prin-
cipally of siliceous shales with their chalky, earthy, or more
areillaceous modifications’’); Sunset (‘‘loecal developments of
eritty sands, brown and yellow limestones, and gypsiferous clays,
perhaps a lower division of the Miocene, the upper division con-
sisting of siliceous shales, typical of the Monterey’’) ; Kern River
Kield (ealled Lower Miocene) ; La Graciosa District (Monterey
shale) ; Summerland Field (siliceous shales of the Monterey) ;
Santa Clara Valley (Lower Miocene, and Monterey shales) ;
Los Angeles Field (siliceous shales of Monterey type) ; Puente
Hilts (‘‘ Lower Miocene, and Monterey’’).

It is to be noted that while Eldridge definitely refers certain
formations in these fields to the Monterey (or to the Monterey
shale), yet he suggests that certain underlying sands or shales
may be Lower Miocene and therefore older than the Monterey.
This foreshadows the erection of a separate formation group and
name for these lower beds that is definitely put forward by
others the following year.

General Character of Decade 1893-1903.—We see, then, that
from 1893 to 1903 the unity of the series was accepted by the
various workers in California Tertiary geology, the name Mon-
terey for the whole series was the only local designation used,
and its areal distribution was recognized along the coast from
Point Arena to San Clemente Island.

38 Calif. Acad. Sei. Memoirs, vol. 3 (1903).
39 U.S. Geol. Surv. Bull. 213, pp. 306-321, 1908.

1913] Louderback: The Monterey Series 201

A few of the workers used the term Miocene instead of
Monterey, although all believed that it represented the same
series and displayed everywhere the same peculiar Lthologic
types which up to that time were considered characteristic of
the Monterey period of deposition in the California coastal
province.

Advantage of Local (Provincial) Name.—Even at that time
it was evident that the term Monterey was preferable to Miocene,
beeause the former designated definitely a series of deposits,
representing a depositional period in a certain province of sedi-
mentation, while the latter represents a time interval referred
to a far distant standard and not necessarily coextensive in time
with the period of deposition here under consideration. Its
determination as Miocene is dependent upon the estimated rela-
tion and meaning of faunal characteristics, the interpretation
of which has varied up to the present and will probably continue
to vary. Furthermore, J. C. Merriam had already in 1898 de-
seribed the San Pablo formation,*® which in Contra Costa County
and, as since determined, at many other localities, overlies the
Mouterey. This series, originally referred by Merriam to the

‘‘middle Neocene,’’ has been considered by some to be Plio-
cene, and by others upper Miocene—this latter view being prob-
ably the prevailing one among palaeontologists at the present
time. Throughout the Coast region, wherever it comes in contact
with the Monterey, it is believed to rest upon the latter uncon-
formably, and over considerable areas the unconformity is very
marked and represents a considerable amount of orogenic dis-
turbance. If we accept the Miocene age of the San Pablo, there-
fore, the Monterey, the period of orogenic disturbance, and the
San Pablo would all be included under the designation Miocene.

PERIOD OF 1904 TO THE PRESENT (1912)

Opening of the Period.—The year 1904 was very prolific of
publeation on the California Miocene and marked the beginning
of the dismemberment of the Monterey series and the multi-
pheation of formational names, both within the limits of this
series and throughout all the Tertiary terranes, so that after a

49 Bull. Dept. Geol. Uniy. Calif., vol. 2, no. 4, May, 1898.

202 University of California Publications in Geology [Vou.7

few years the array becomes confusing and rather discouraging
to one who wishes to acquaint himself with the real essentials of
the geological history of that time.

Salinas Valley, Hamlin, 1904.—It was Homer Hamlin who
suggested the term ‘*‘ Vaquero sandstone’’ for the sandy lower
portions of the Monterey series in the Salinas Valley region.
In 1904 in a paper on the Water Resources of the Salinas Valley,
California,*’ he defines it as follows: ‘‘ Vaquero sandstone.—
In the Salinas Valley, the Vaquero sandstone is a well defined
formation. So far as observed in this region it rests uncon-
formably on the Basement complex and on stratified terranes
older than the Neocene, being thus in this locality the oldest
known member of the Neocene; in other localities Neocene for-
mations are found below the Vaquero sandstones, indicating that
it is not the basal member of the Neocene.

“The Vaquero formation is a rather coarse, uniformly gray,
white or light-yellow quartzose sandstone with an occasional
stratum of granitic pebbles. It is of great thickness along the
eastern slope of the Santa Lucia range, especially in Los Vaqueros
Valley; hence the designation proposed by the writer for this
series of sandstones. . . . The following fossils have been found
in the Vaquero sandstone: Balanus, sp.?; Mytilus, sp., probably
mathewsonu Gabb; Ostrea tayloriana Gabb (Young) ?; Ostrea
titan Conrad?; Pecten magnolia Conrad; Turritella hoffmanni
Gabb?; Chione mathewsonit Gabb; Chione n. sp. (large, charac-
teristic of this horizon) ; Mactra aff. catilliformis Conrad; Pecten
estrellanus Conrad; Pecten (Chlamys) n. sp., 8.; Pecten (Pla-
gioclenitum) n. sp. A.”’

San Luis Quadrangle, Fairbanks, 1904.—Fairbanks adopted
Hamlin’s nomenclature for the San Luis Folio, which was pub-
lished (appearing in fact earlier) the same year. He places in
the ‘‘ Vaquero Sandstone’’ that lower portion of the series which
is made up of sandstone and conglomerate ‘‘because of their
extensive occurrence on Los Vaqueros Creek.’’ Beyond the quad-
rangle it reaches a great thickness, especially ‘‘along the southern
side of the granitic area.’’ It may be 5000 to 6000 feet thick.

41U. 8. Geol. Surv., W. S. and Irrig. Paper no. 89.

1913] Louderbach: The Monterey Series 203

Within the quadrangle itself it varies only up to about 500 feet
in thickness. ;

The ‘‘Monterey shale’’ ineludes the clay shales and lime-
stones, and the siliceous shales in all from 5000-7000 feet thick.
He considers that it lies conformably over the Vaquero sandstone,
and states that ‘‘it seems probable that these sandstones and
conglomerates were in origin, partly at least, contemporaneous
with the bituminous Monterey shale, the former representing the
shore deposits, and the latter representing deposits formed at.
a considerable distance from land.’’ The ‘‘Monterey shale’’ is
also shown to contain voleanie ash beds. The conformable series,

Vaquero sandstone—Monterey shale, is separated from both
earlier and later deposits by marked unconformities.

It will be noted that the separation of the series is on a purely
hthologie basis. and the Vaquero sandstones of one part of the
field are believed to be contemporaneous and to have originally
graded laterally into the Monterey shale in another part. They
are, therefore, merely depositional facies of the same series of
deposits, as believed by the present writer. The unfortunate
thing about Fairbanks’ work is that he omitted the outward
sign of the essential unity that he believed in—the name of the
series as a whole, and presented it in his columnar section as
two separate entities, representing two different periods of depo-
sition, which idea his descriptions oppose.

San Mateo County, Hachl and Arnold, 1904.—In this same
vear (1904) Haehl and Arnold in discussing the ‘‘ Miocene Dia-
base of the Santa Cruz Mountains in San Mateo County, Cali-
fornia,’’!? presented these two divisions as representing different
time intervals,—different faunal stages. They described’ ‘the
lower Miocene”’ as ‘‘a series two or three thousand feet thick of
massive, coarse, yellowish sandstone layers, interbedded with a
few layers of varying thickness of dark colored argillaceous shale,
the whole overlain by three or four hundred feet of thin bedded
siliceous shales. The lower part of this series of beds, including
most of the sandstone, appears to have the same fauna and oceupy
the same stratigraphic position as the Vaquero sandstone of the
Salinas Valley. The name ‘Vaquero’ will, therefore, be used

42 Proe. Am. Phil. Soe., vol. 48, pp. 16-53 (1904).

204 University of California Publications in Geology [Vou.7

to designate the lower Miocene sandstone in the area under dis-
cussion’’ (p. 19). <A fossil list, the most complete published up
to that time, is given with those fossils supposed to be charac-
teristic of this horizon indicated by asterisks.

Returning to the overlying shales, they say ‘‘These shales
represent at least a part of the Monterey series,*? which is sup-
posed to be of middle Miocene age’’ (p. 20). <A list of fossils
is given for the Monterey and those characteristic of the horizon
designated. It is said, however, ‘‘The upper part of the Vaquero
sandstone series, at least that part showing alternating beds of
sandstone and shale with a tendeney to grade from sandstone
vertically upward into shale, may be the inshore equivalent of
some of the Monterey shale found at the typical locality in the
region around Monterey.’’ The faunal character of this over-
lapping portion is not explained.

The Formation-Faunal Stage Fallacy.—lrrespective of whether
we aeree or do not agree with Haehl and Arnold’s determination
of the particular beds in San Mateo County as ‘‘lower Miocene”’
and ‘‘middle Miocene’’ respectively, this idea of the ‘* Vaquero
sandstone’’ and the ‘‘ Monterey shale’’ as representing two dif-
ferent time intervals determinable by fossils paved the way for
much confusion which actually followed. The fundamental
trouble lay in this idea: These formations, where studied, could
be divided lithologically into two groups called by two forma-
tional names; palaeontological studies showed that there were
two distinguishable faunas supposed to represent two different
time intervals; therefore these two faunas correspond to the
two ‘‘formations,’’ which latter must then have been deposited
in thése two different periods of time. The far-reaching effects
of this fallacy will be shown in following the later history.**

48 Thus using Monterey series not in accordance with its previously
established usage, but corresponding to the ‘‘ Monterey shale’’ of Hamlin
and Fairbanks.

44As far back as 1895, G. H. Ashley had published in the Proe. Cal.
Acad. Sci., 2d Series, vol. 5, pp. 273-367, and in brief form in Jour. of
Geol., vol. 3, pp. 434-454 (1895), a discussion of the ‘‘ Neocene Stratig-
raphy of the Santa Cruz Mountains of California,’’ in which he attempted
to establish two series—the Pescadero and the Monterey-Merced. He
considered each of these to be a practically conformable series with per-
haps slight local breaks in them. In the former he included stratigraph-

ically the San Francisco sandstone of Telegraph Hill and other parts of
San Francisco, and of San Bruno Mountain (generally accepted as

1913] Louderback: The Monterey Series 205

San Pablo and General, Merriam, 1904.—In the same year,
J.C. Merriam* in ‘‘A Note on the Fauna of the Lower Miocene
in California’’ was eareful to regard the distinction between
hthological types, faunal facies and faunal zones. He said:
““One of the most characteristic phases of the Miocene in Cali-
fornia is the Monterey shale. The fauna of this formation, as we
know it, is hmited to foraminifera, radiolaria, fish, cetaceans, a
crustacean and a few mollusea. Among the last, Pecten peck-
hami, the indefinite Tellina congesta and a Leda are the most
common forms. The fauna belongs to a deep water facies and
must not be confused with the faunas of sandy, shallow water
deposits. At many places where sandstone is interstratified with
the shales, a very sudden change of the fauna is noticed, nearly
all of the typical shale species dropping out, but reappearing
in shaly layers above’’ (p. 377).

Depositional and Faunal Facies.—If we take this statement in
connection with the fact that in western Contra Costa County, as
had been shown by Lawson in the section quoted above, p. 199,
the Monterey series is made up of a succession of sandstones
(Vaquero type) and bituminous shales (Monterey type), and

Mesozoic, possibly Jurassic), the sandstones and shales of Pt. San Pedro
(recently shown to be Eocene), the conglomerates and sandstones exposed
between Pescadero point and Pigeon point, said to be the best developed
part of the series and from which apparently it received its name (classed
in the Santa Cruz Folio, 1909, as Chico Upper Cretaceous), and various
other sandstones, including those called Vaquero by Arnold and Haehl.
From palaeontological evidence he considered the series partly Miocene
and largely Eocene (?). He was inelined to believe that the ‘‘ Meta-
morphic’’ rocks of the San Francisco peninsula were part of the series,
but separated them as a concession to current geological opinion. He
also considered the Monterey (Miocene) and the Merced (Pliocene) as
forming a conformable series.

Such a system which grouped together formations belonging to entirely
ditrerent and differently conditioned periods of sedimentation and so
widely separated in time and by widespread and important uneconform-
ities, and which placed the chief division of all the formations from
Mesozoic to Quaternary in the midst of a conformable series (the Mon-
terey Series) was so evidently out of touch with the facts that it found
no adherents and had practically no direct effect on the development of
the understanding and nomenclature of the Tertiary formations. It may,
however, be looked upon as sowing the seed that led to the use of palaeon-
tological criteria for dividing the Monterey Series into two formations
and that bore its first fruit in the paper above discussed.

45 Bull. Dept. Geol. Univ. Calif., vol. 3, no. 16, pp. 377-881, Mareh,
1904. This paper, treated here in the order convenient for logical dis-
cussion, was in reality the first paper on the California Miocene to appear
in 1904.

206 University of California Publications in Geology [Vou.7

that in a section 4280 feet thick the Monterey shale type occurs
within 400 feet of the bottom, and within 1800 feet of the top,
and also in the middle part of the section, and that when it
recurs its fauna recurs, we have a key to the proper understand-
ing of the Monterey series. The shale with its fauna may oceur
practically at any part of the series, if the conditions of depo-
sition (and therefore of faunal environment) are favorable. It
does not correspond to a faunal time zone, except to the general
zone of the Monterey series deep water fauna. Its relationship
to shallow water faunal zones can only be determined if it con-
tains frequent intercalations of fossiliferous littoral sands. The
faunas generally published as of the ‘‘ Monterey shale’’ strati-

graphic formation are mixtures of the Monterey Series ‘‘shale
fauna’? and that of occasional littoral sands from the upper part
of the series. As example, it may be noted that the faunal list
just referred to as given by Haehl and Arnold for the Monterey
shale contains all the forms given by Merriain for the ‘“‘shale
fauna’? and found apparently in the ‘*‘Vaquero’’ zone as well
as in the upper part of the series. It merely happens that in
the areas studied by Fairbanks, Haehl and Arnold, the lower
part of the series is chiefly sand (or conglomerate), and there-
fore does not carry the ‘‘shale’’? fauna, and that after the shale
appears it shows no more fossiliferous sands to the top of the
series—so that the ‘‘ Vaquero’? fauna is not found interealated
in the supposed later fauna.

Faunal Zones.—That the littoral deposits of the series do show
faunal zones is brought out by Merriam in the paper just referred
to. ‘‘The upper division has its nearest affinities with the San
Pablo, from which it can be distinguished by the presence of
Clypeaster (2?) brewerianus, Trochita costellata, several new
‘“The fauna of the lower

species of Modiola and other forms.’’
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’’ (p. 378). He gives a faunal list and pro-
poses that it be called the zone of Agasoma gravida.

Turning then to a general discussion of the formations in
the southern portion of the State, he concludes that the Agasoma
zone is widely developed and suggests that it may be divisible

1913] Louderback: The Monterey Series 207

into two horizons—the zone of Turritella hoffmanni and that of
T. ocoyana, the former being the older, and as it is not found
to the east of the Great Valley, it may mean that ‘‘the sea had
not reached as far east in the earhest Miocene as it did later,
and that the thick shale beds over the lower sands of the western
region were formed while sandy 7. ocoyana beds were being
deposited in the east’’ (p. 381).

Southern Coast Ranges, F. M. Anderson, 1904.—F. M. An-
derson this same year presented in abstract form*® the ‘‘Stra-
tigraphy of the Southern Coast Ranges of California,’’ with
special reference to the interior ranges. He makes use of the
twofold division, calling the lower the Peseadero sandstones
(after Ashley), which he says reach a thickness of 11,000 feet,
in the Carrisa | Carrizo] Valley of 14,000 feet—alternating sand-
stones and shales, the former predominating; and the upper, the
Monterey shales, 3400 feet, including 200 feet of sandstone, and
some voleanic ash.

Coalinga Region, F. M. Anderson, 1905.—The following year
Anderson published* a ‘‘Stratigraphiec Study in the Mount
Diablo Range of California,’’ dealing especially with the terri-
tory in the vicinity of Coalinga and south. [He recognized the
Monterey shales, which he claimed were 5500 feet thick at Car-
nera [Carneros] Springs, below which are sands and shales.’’
In the light of stratigraphic studies farther north, it is evident
that the entire series of sands and shales below the Monterey
Shales should be regarded as a distinct member of the Miocene,
and the name 7emblor Beds is suggested to embrace this agere-
gate of strata’? (p. 170). Various lists of fossils are given for
different localities, many forms of which correspond to the
‘“Vaquero sandstone’’ list given by Haehl and Arnold, and to
Merriam’s Agasoma zone (Turritella ocoyana stage), while some
appear more like the ‘‘Monterey shale’’ types of Haehl and
Arnold. As Anderson materially revised his stratigraphy in a
later paper, further discussion is postponed until the later report
is taken up. For the present the point to note is the introduction

of the term ‘‘Temblor’’ as a stratigraphic unit, supposed to be

46 Geol. Soe. Am. Bull., vol. 15, pp. 581-582 (1904). ,
47 Calif. Acad. Sei. Proc., 3d series, Geology, vol. 2, pp. 155-248 (1905).

208 University of California Publications in Geology (VoL. 7

characterized by a definite fauna, representing a definite time
interval. Its correlation with formations in other parts of the
State is hinted at, but not definitely stated. Anderson refused
to compare it with the ‘‘ Vaquero sandstones’’ of the Salinas
Valley, because they ‘‘lack thus far any faunal description’’ and
Fairbanks’ correlation of these with ‘‘beds occurring south of
the Santa Lucia Range is not supported by any faunal evidence.’’
He made no reference to the Pescadero series, nor in his later
publications does he ever refer to it again. Nor is it used by
any other writer.

California Formations and Faunas, Arnold, 1906.—In 1906
Arnold published a monograph on the ‘‘Tertiary and Quater-
nary Pectens of California,’’** in Part I of which he presented
the California post-Cretaceous geologic column, defined briefly
the standard formations, listed their faunas and indicated their
supposed characteristic species.

He emphasized the fallacy that was discussed above (p. 204)
by making the ‘‘Vaqueros sandstone’’*® a definite formation

undcrlying the ** Monterey shale’? and equivalent to the ‘‘Aga-

soma zone.’’ From the list of localities given it is evident that
he considered the lower Miocene beds of Contra Costa discussed
by Merriam, the Salinas and Los Vaqueros Valley beds described
by Hamlin, the sandstones of the San Luis region discussed by
Fairbanks, the Temblor beds of Anderson, the Santa Cruz Moun-
tains beds previously described by himself and Haehl, the Poso
Creek beds (Ocoya Creek beds of Blake and others) of the Sierra
Nevada foothills, and various deposits in southern California, as
being Vaqueros or representing the horizon of the Agasoma zone.

THe described the ‘‘ Monterey shale’’ as a ‘‘very characteristic
shale formation ... underlain conformably by the Vaqueros
sandstones at most localities, but at a few it rests directly upon
older rocks.’’ The faunal list is made to include some forms
‘*found both below and above it, or in its included sandstones. ’’
Of the definitely determined species given, it may be noted that

48 U.S. Geol. Surv. Prof. Paper, no. 47 (1906).

49 From this time forward, without any particular explanation, the
form Vaqueros replaces Vaquero in the literature, apparently to conform
to some rule of etymology.

1913 | Louderbach: The Monterey Series 209

‘“shale facies’’ or are found

they are either characteristic of the
in the Vaqueros (or Temblor, which he considers equivalent).
He admitted that ‘‘As suggested by Doctor Lawson, the shale
probably has an inshore equivalent of sandstone, whose fauna is
doubtless entirely different from that of the shale and probably
shows a marked resemblance®® to that of the underlying Vaqueros
and overlying Contra Costa County Miocene.’’ This hypothet-
ical marked resemblance is, however, apparently not considered
to amount to identity, and the two depositional facies are pre-
sented as independent formations representing different time
intervals. The upper faunal zone of the littoral facies described
by Merriam (loc. cit.) is evidently misinterpreted as a formation
“lying between the Monterey shale and the San Pablo,’’ and
called by Arnold (supposedly after Merriam, though I can learn
of no such usage) the ‘‘Contra Costa County Miocene.’’

Santa Clara Valley Oil Fields, Eldridge and Arnold, 1907.—
The year 1907 produced a rich harvest of California Tertiary
literature in the form of bulletins on the oil districts of the
Southern Coast Ranges. The first’! of these was on ‘‘the Santa
Clara Valley, Puente Hills and Los Angeles Oil Districts.’’ The
part on the Santa Clara Valley district has already received
considerable attention in Part I of the present paper and need
not be discussed at leneth here. It is noteworthy in adding to
the Vaqueros sandstone the terrigenous shales and limestones
and a certain fraction of the siliceous shales (all previously
assigned to the Monterey by Fairbanks and others) because in
the iower part there was found within them a ‘‘ Vaqueros fauna,’’
the name being appropriately changed to ‘‘ Vaqueros formation’?’ ;
including the resi-

by)

and in the creation of a ‘‘ Modelo formation
due of siliceous shales and certain intercalated sandstones, the
base of the Modelo being placed at ‘‘the sharp line’’ between
the underlying siliceous shale and the Modelo sandstone. How-
ever, on the south of the valley and in the western part of the
field, the line is drawn between siliceous shale and underlying
terrigenous beds following the usage of others. This field is a

50 Italics not in the original.
51U. S. Geol. Surv. Bull., 309 (1907).

210 University of California Publications in Geology [Vou.7

good example of the impossibility of practically applying the
faunal division idea, and the inconsisteney to which the mixed
notion of faunal and formational unity of the Vaqueros may
lead.

Puente Hills, Eldridge, 1907.—In the section on the Puente
Hills Oil District,*? by Eldridge, a new term is introduced for
what is evidently the local representative of the Monterey series
—the Puente formation. This is said to be ‘‘the equivalent: of
at least a part of the Modelo formation, and possibly ineluding
some of the Vaqueros’’ (p. 103).

The ‘‘Puente formation’’ is said to consist of 2000 feet of
shale, chiefly earthy but with minor siliceous layers and some
thin sandstone layers and limestone lenticles; followed by a
heavy bedded coneretionary sandstone, 300 feet in the western
part of the hills, 1000 feet in the eastern portion; and wanting
in the southern portion; then 300-400 feet of siliceous shale with
a few sandstone beds and quartzo-caleareous concretions. The
relations of this massive coneretionary sandstone to the over-
and underlying shales suggests strongly the relation of the mas-
sive concretionary Modelo sandstone of the Santa Clara District
to its over- and underlying shales. And its rapid thinning out
and perhaps disappearance towards the sea is remarkably sug-
eestive of the Modelo conditions.

Eldridge hesitates to finally accept the equivalence of the
Puente to the ‘‘ Monterey’’ (using this in the sense of ‘‘ Monterey
shaie’’ of Arnold, for example) because of ‘‘the marked litho-
logie similarity of portions of the lower division of the Puente
formation to certain strata in the Santa Clara Valley and else-
where in the Coast Range that have been determined by their
fossils to be lower Miocene and possibly Oligocene—lower than

the Monterey.’’ Here again we have the formation-faunal stage
fallacy. Nevertheless ‘‘from geologic conditions to the south
of the Puente Hills in the Santa Ana Range, however, the writer
is inelined to consider the entire succession of beds described
above as the local equivalent of the Monterey.’’ As in the Santa
Clara Valley, this series underlies the ‘‘Fernando formation’’

unconformably.

52 Loc. cit., pp. 102-137.

1913 ] Louderback: The Monterey Series 211

Los Angeles, Arnold, 1907.—In the part dealing with ‘‘the
Los Angeles Oil District,’? Arnold®* uses the same term Puente,
and divides the Miocene representatives into the ‘‘ Puente sand-
stone’’ and the ‘‘Upper Puente shale.’’ These he believes to
correspond to the deposits of the same name in the Puente Hills.
But his Puente sandstone here is fossiliferous and yields a fauna
that he considers to be characteristic of the ‘‘lower Miocene
throughout the southern San Joaquin Valley and as far south
as the Santa Ana Mountains’’ and ‘‘equivalent®* in general to
the Vaqueros sandstone of central California.’’ It apparently
corresponds to the Agasoma zone and the stage of Turritella
ocoyana and T’. variata.

he lower portion of the ‘‘Puente sandstone’’ is described
as argillaceous, and as possibly equivalent to the ‘‘lower Puente
shale’’ of the Puente Hills.

The ‘‘upper Puente shale’’ is said to consist of alternating
sandstones and shales throughout, the lower 1000 feet being thick
bedded and grading into the Puente sandstone with ‘‘no sharp
line of demareation,’’ the upper thousand feet thin bedded.
Mosi of the shale in the lower part of the ‘‘ Upper Puente shale,’’
and also ‘‘many of the shale beds interstratified with the Puente
sandstone,°® are of the hard white siliceous variety character-
istic of the Monterey shale in the Coast Range.’’ They carry
abundant remains of micro-organisms.

We have here then a continuous series of deposits at least
4000 feet thick, carrying sandstones from top to bottom and
interbedded throughout with clay shales, and siliceous shales of
the Monterey type, the sandstones more abundant in the lower
portion, but a 50-foot stratum at the top, the lower sandstones
more or less fossiliferous and showing a fauna similar to the
Vaqueros of the central ranges. Thus again we get repetitions
of ‘‘Monterey shale’’ and ‘‘ Vaqueros sandstone’’ in a way similar
to the western Contra Costa County area already described.

53 U.S. Geol. Surv. Bull. 309, pp. 188-198 (1907).

54 The correlation table on p. 143 of that bulletin does not agree with
the deseription in the text.

55 Italics not in original,

212 University of California Publications in Geology [Vou.7

Summerland District, Arnold, 1907.—In the ‘‘Geology and
Oil Resources of the Summerland*® District’’ which appeared this
same year, Arnold describes the ‘‘ Vaqueros formation’’ and the

‘*Monterey shale.’? These designations were used and were easy
of application because the territory studied lies within that
coastal belt where the Monterey period of deposition opened
with a sandy facies with subordinate shales (785 feet thick in
the locality described) graded into predominant clay shales with
calcareous shales and eoneretions (1650 feet near Summerland)
and finally into dominant diatomaceous shales and siliceous cherts
with occasional ash beds. The lower sands and terrigenous shales
are said to contain no characteristic fossils, but their ‘‘strati-
eraphic position and lithologie similarity’’ to the fossiliferous
beds already described in the Santa Clara District ‘‘leave no
doubt in the mind of the writer as to its correct correlation”’
with the Vaqueros. The dominant diatomaceous shales in the
upper part of the series are called ‘‘ Monterey shale’’ and contain
besides the microscopic organisms a few species of the shale
fauna of Merriam. Here we return to the distinction based
on lthologie types, but divided as in the Santa Clara District
(and not as originally by Fairbanks farther north) for reasons
already discussed.

Santa Maria District, Arnold and Robert Anderson, 1907.—
In their bulletin’? on the ‘‘Geology and Oil Resources of the
Santa Maria Oil District, Santa Barbara County,’’ Arnold and
Robert Anderson used the same classification that was used in
the Summerland district just described. The Vaqueros for-
mation was placed in the ‘‘Tejon-Sespe-Vaqueros terrane,’’ as
they considered that the purpose of the bulletin did not warrant
the time necessary to trace the lines between the constituent
members. A table of ‘‘Vaqueros (lower Miocene) ’’ fossils and
localities is given (p. 32). The ‘‘Monterey shale (middle Mio-
cene)’’ is said to follow the Vaqueros conformably, the division
being placed on lthologie ground at the end of the calcareous
shales and beginning of the dominantly siliceous shales. The
Monterey shale is said to be 5200 feet thick.

56 U. 8. Geol. Surv. Bull. 321 (1907).

57 U. S. Geol. Surv. Bull. 322 (1907); also earlier briefer account in
Bull. 317 (1907).

1913] Louderback: The Monterey Series 213

““The Vaqueros and Monterey terranes taken as wholes are
distinct units, representing periods of deposition of entirely dif-
ferent character.’ As indicated by the rocks, deposition was
continuous between the Vaqueros and Monterey and the change
in character came suddenly, although less so in some places than
in others. The general nature of the Vaqueros series is detrital ;
that of the Monterey organic. The former contains many well
preserved molluscan forms, the latter few. Close to the line
between the two, beds predominatingly of a gravelly or sandy
nature or those bearing fossil mollusks are considered part of
the Vaqueros; those of a fine texture and of flinty or opaline
or chaleedonic nature, part of the Monterey’’ (p. 34).

‘““A paucity of recognizable mollusean fossils is one of the
prominent characteristics of the Monterey in this region, as in
most others in the Coast Ranges where it outerops. Moreover,
the other fossils that it contains are of little value in indicating
its age. Its position in the geologic column is determined by the
lower Miocene fossils found just below its base in the Vaqueros*®
and by the upper Miocene fossils found at or near the base of the
Fernando formation which lies unconformably above it’’ (p. 47).
Yet it is said ‘‘These shales make up the Monterey formation and
are probably representative of the whole of middle Miocene time”’
(p. 33).

We have here a confession of the flimsy evidence upon which
the *‘ period of deposition’’ of the siliceous shales is determined.
The alternation of organic shales and sandstones (‘‘ Vaqueros’’)
found in the Los Angeles district and the rapid fluctuation in

the relative proportions of ‘‘ Monterey’? and ‘‘ Vaqueros’’ in the
Santa Maria district (see p. 191) apparently did not lead the
writers to see that these two types were merely depositional facies,
and that the line drawn between them in the Santa Maria field
while lithologic, and having an important economie and geologic
bearing, in no sense represents a horizon or division line between
the ‘‘lower Miocene’’ and ‘‘middle Miocene.’’

Whatever period of time referred to the European scale the
rocks of the Monterey series of the Santa Maria district repre-

58 Italies supplied.

59 Ttalies not in original.

214 University of California Publications in Geology [Vou.7

sent, it seems certain that the organic shales at some points
represent part of the earlier half of the period, and the sand-
stones or terrigenous shales represent part of the later half at
other points.

Coalinga-Mchittrick Region, F. M. Anderson, 1908.—In 1908
F. M. Anderson®’ published ‘‘A Further Stratigraphie Study in
the Mount Diablo Range of California,’’ dealing particularly
with that part of the range between Cantua Creek and McKit-
trick. He used the same terms for the rocks under discussion
as he did in his former paper, the ‘‘Temblor beds’’ and the
He considered the Temblor to be the more
persistent of the two and also ‘‘best characterized by fossils, and
is therefore the most easily recognized faunally’’ (p. 18). Their

‘*Monterey shale.’

usual thickness is given as 450-550 feet. The Monterey shale
is said to be 5000 feet thick north of the Temblor ranch house
and to decrease to 250 or 300 feet near Coalinga® (the ‘‘ Big
of the oil men doubtfully referred by Anderson to the
Monterey.

Anderson again criticized very strongly (pp. 38-39) the use

Blue

of the term ‘‘ Vaquero sandstone’’ because the ‘‘type’’ locality
(Los Vaqueros Valley) lacked ‘‘faunal or even stratigraphic
description,’’ nor is it delineated on any published map. He
admits, however, that ‘‘most of the strata that have been de-
scribed under the name ‘Vaquero sandstone,’ as far as known,
represent a well characterized horizon of the Lower Miocene, and
as such are without doubt to be correlated with the Temblor beds
of the Mount Diablo range’’ (p. 39).

As to the siliceous shales, ‘‘the Monterey shales occurring
in the Middle Miocene of California have generally been called
by that name; hence little is to be said regarding their corre-
lation with the same in the Mount Diablo range. In general,
however, there is a tendency to trust too far to lithological char-
acters in their identification, and it is not unlikely that error

60 Calif. Acad. Sci. Proce., 4th Ser., vol. 3, pp. 1-40 (1908).

61 In his earlier publication (see loc. cit., p. 207 of this paper) some of
the beds evidently belonging to the Monterey series were included in his
““Coalinga beds,’’? but in this paper they are removed from that category
and placed with the Temblor, and the term Coalinga is therefore not here

discussed. Diatomaceous shales near Coalinga in the previous paper re-
ferred to the Monterey are in this paper called Eocene or Oligocene.

1913] Louderback: The Monterey Series 215

has thus originated more than once in the application of this
name.’’ Nevertheless it may be pointed out that Anderson no-
where gives a characteristic fauna for his ‘‘Monterey shale’’
and really makes the division on lithologic grounds himself.
In fact the fossils which he reports from the Monterey shale are
the same that are found in the diatomaceous shale which he first
called Monterey but which in his later paper he placed in the
Eocene or Oligocene because he considered that it lay uncon-
formably below sandstones carrying a Temblor fauna.

We find here again an unrealizable ideal system of two for-
mations, two faunas, two periods of deposition—and an actual
condition of the lithological division of a series dependent on
depositional facies varying from place to place in relative thick-
ness.

Geological History of Coast Ranges, Lawson, 1908.—In this
same year in the Report of the State Earthquake Investigation
Commission"? on the California earthquake of April 18, 1906,
Lawson outlined briefly the geological history of the Coast
Ranges. Withcut discussing the ideas of others he showed that
his view of the unity of the Monterey series had been unaffected
by the numerous publications that had dismembered it and given
its parts and different areas various names and interpretations.
He says ‘‘Miocene time in the Coast Range region was charac-
terized by a progressive subsidence with oscillations of the coast.
The Miocene sea gradually transgrest the continental margin
from the southwest, and as it did so spread a formation of arkose
sands and conglomerates over the greater part of the Southern
Coast Ranges. This was followed, as the water deepened with
progressive subsidence, by a remarkable deposit of bituminous
shales’’ (p. 9).

He notes the oscillatory nature of deposition in the Bay of
San Francisco region (giving 9 divisions instead of the 7 he
previously reported—5 sands and 4 bituminous shales). ‘‘ This
series is known as the Monterey series.’’? ‘‘ While the oscillation
of the coast so clearly recorded in the strata near the Bay of
San Francisco is not apparent in the southern Coast Ranges,
it is by no means certain that they were not affected in a similar

62 Carnegie Inst. of Wash., vol. I, Part I (1908).

216 University of California Publications in Geology [Vou.7

way. The vertical movement involved was not great, and such
a movement might have extended over the deeper portions of
the area of deposition in Monterey time without effecting a suffi-
cient change in the depth of the water to alter the character of
the sediments’’ (p. 10).

I have pointed out above that similar oscillations did take
place in the Santa Clara Valley region, Los Angeles district and
Puente Hills.

Santa Cruz Folio, Branner, Newsom, and Arnold, 1909.—
Considerable areas of rocks representing the Monterey series
have been mapped by Branner, Newsom, and Arnold in the Santa
Cruz quadrangle, the folio®* for which appeared in 1909. They
are presented as two formations separated by an unconformity,
and presumably representing different time intervals in the
ceologic seale.

“The Vaqueros sandstone, of lower Miocene age, is one of
the most important formations of the quadrangle. . . . The sand-
stone varies in texture from fine grained beds to conglomerate,
but is usually medium grained. Generally it is brown or buff
in color... . The Vaqueros in general les conformably above
the San Lorenzo formation, and there is often a gradual change
from one formation to the other. . . . Southwest of Ben Lomond
Ridge, Big Basin, and Butano Ridge the thin sandstone at the
base of the supposed Monterey shale, tentatively included with
the Vaqueros, overlaps unconformably the San Lorenzo, the
Butano and the pre-Cretaceous diorite’’ (p. 4).

“The relation of the Vaqueros sandstone to the overlying
beds is not so elear’’ (?) ‘‘as are its relations to the underlying
strata. Around the northwest end of Butano Ridge the diato-
maceous shale (supposed Monterey) rests directly on the Bu-
tano, and the thin sandstone (regarded as possibly Vaqueros)
is absent. Elsewhere in the quadrangle there is commonly a
marked difference in the dips of the Monterey strata and those
of the Vaqueros sandstone, and an unconformity is therefore
believed to exist generally between the two formations. Inas-
much, however. as the line of contact nearly always occurs in
densely wooded or chaparral-covered regions and where the rocks

63 U. S. Geol. Surv., Santa Cruz Folio, California, no. 163 (1909).

1913 ] Louderback: The Monterey Series 217

are much crushed and folded, it is not possible to say with cer-
tainty that there is at all places an unconformity between the
Vaqueros sandstone and the overlying strata.’’

The fact that everywhere else the Monterey series exhibits
a conformable relation throughout and that even within this
area the sandstones.underlying the shale in some places are
distinctly conformable below them, and that where unconform-
able relations are suggested by different dips the contact areas
are not distinctly visible should make one doubt the correctness
of this determination which the authors themselves speak of in
a doubtful way. However, even if the suspected unconformity
does oceur, it must be a very local and minor feature and can
hardly be accepted as marking a time boundary between two dis-
tinct formations, which as has been frequently pointed out, are
‘*determined’’ in general by quite different characteristics which
change at various horizons.

The idea expressed (p. 10, col. 3) that ‘‘after the deposition
of the Vaqueros sandstone at least a portion of the region appears
to have been raised, and was probably folded and faulted; in
parts of the area considerable erosion appears to have taken

place,’’ does not seem diastrophically probable. That within
part of that comparatively small area such activities as uplift,
folding, faulting, considerable erosion and then subsidence,
should take place, while over other parts of the area and in the
neighboring regions quiet deposition was going on is hardly to
be expected and should be backed up by very definite or strong
evidence before it can be accepted.

Again the authors say ‘‘There are few localities where the
Vaqueros sandstone is fossiliferous, but at those places the rocks
yield an abundant fauna of unmistakable lower Miocene age.
As would be expected in a formation composed largely of con-
olomerates and coarse sandstones, the Vaqueros contains a shallow
water or littoral fauna’’ (p. 4, col. 3).

In other words, all of the sandstones and conglomerates not
found above diatomaceous shale were placed in this ‘‘ formation”?
on a lithologic basis, while the fauna found in a few localities

was considered ‘‘characteristic’’ of the horizon supposedly repre-

sented by them all.

218 University of California Publications in Geology [Vou.7

‘““The fauna is characterized by a great abundance of indi-
viduals of several species of the genus Agasoma .. .”’.

Turning now to the ‘‘Monterey shale,’’ ‘‘middle Miocene,’’
it is said that ‘‘In the Santa Cruz quadrangle the Monterey shale
consists chiefly of diatomaceous shale with here and there inter-
calated sandstone beds. . . . The diatomaceous shale composes the
greater part of the formation.’’

‘*Loeally the Monterey shale contains abundant fossils, leav-
ing no doubt as to its age. . . . Some of the areas of diatomaceous
shale supposed to be of Monterey age have thus far yielded no
determinable fossils’’ (p. 3).

‘“Rew species are known in the formation, but this paucity
in the number of species is partly compensated for by the abun-
dance or rather widespread distribution of Pecten peckhami
Gabb, Yoldia impressa Conrad, Arca obispoana Conrad, and
Tellina congesta Conrad. The first two of these are found spar-
ingly also in the San Lorenzo formation (Oligocene) ; neverthe-
less their great abundance in the Monterey make them more or
less useful for purposes of correlation.’’ .

We have the admission here that two of these forms are
found in the ‘‘Oligocene,’’ and therefore cannot be considered
characteristic of the ‘‘age’’ of the shale, and it may be added
that Tellina congesta is one of the shale fauna that is found very
low in the Monterey series in Contra Costa County and it is
doubtfully determined by Anderson" in the shales near Coalinga
considered by Arnold and others to be Eocene or Oligo-
cene; and that Arca obispoana® is reported from the Vaqueros
(Temblor of Anderson) associated with an Agasoma fauna in
the vicinity of Coalinga. One may hardly look upon these as
‘leaving no doubt’’ as to the ‘‘middle Miocene’’ age of the
formation. A fossil list of 15 is also given with those ‘‘sup-
posedly characteristic of formation’’ indicated. For eleven of
these specific determinations are given of which all but two have
been reported from other localities as associated with ‘‘charac-
teristic’? Vaqueros or San Lorenzo fossils. The two not so found

64 Anderson, Proce. Cal. Acad. Sci., 4th Ser., vol. III, p. 16 (1908).
65 Arnold, U. 8. Geol. Surv. Bull. 396, p. 17 (1909), and Bull. 398, p. 86
(1910).

1913] Louderback: The Monterey Series 219

(Mactra montereyana Arnold and Venericardia montereyana
Arnold) have not as far as known to the writer been reported
from any locality but that of original discovery, and their geo-
logic relations are unknown.

The thickness of the ‘‘Monterey shale’’ is given as 5000+
feet, of the Vaqueros sandstone 2700+.

In the Santa Cruz Folio, then, the rocks of the Monterey
series have been presented as two distinct formations apparently
separated lithologically, faunally, and representing two epochs
of deposition (lower Miocene and middle Miocene respectively ),
and separated in part by an unconformity. But a critical esti-
mation of the evidence presented indicates that the divisions
have been made throughout on lithologie difference (depositional
facies), that the unconformity is not evident where exposures
are clear but only suspected in certain areas where contact areas
are hidden and even if present we have no reason to suspect that
it marks the time of supposed depositional or (and) faunal
change. Furthermore, the supposed characteristic fauna of the
Monterey is chiefly a shale facies, whose forms are known to
the base of the Miocene and in large part into strata supposed
to be Oligocene (San Lorenzo) or Eocene (Coalinga Tejon shale)
and containing no element that is even fairly surely known to

characterize a ‘‘Monterey shale’’ or ‘‘middle Miocene’’ time
period. It is evident that this area which seemed at first to offer
especially good grounds for the distinction is on no stronger
basis than others already discussed.

Environment of Tertiary Faunas, Arnold, 1909.—A general
statement of Arnold’s views appeared this same year.®° As the
individual papers in which his evidence is presented have already
been discussed, this general paper (in which no evidence is pre-
sented) may be passed over without discussion.

Coalinga Oil District, Arnold and R. Anderson, 1910.—In
1910 Arnold and Robert Anderson published®* an extensive
report on the ‘‘Geology and Oil Resources of the Coalinga Dis-
trict.’’ The ‘‘Vaqueros sandstone (lower Miocene)’’ is de-

66 Arnold, Environment of the Tertiary Faunas of the Pacific Coast of
fhe United States, Jour. of Geol., vol. 17, pp. 509-533 (1909).

67 U. S. Geol. Survey, Bull. 398 (1910). See also the Preliminary Re-
port, Bull. 357 (1908), and the Palaeontological Report, Bull. 396 (1909).

220 University of California Publications in Geology | Vou.7

scribed, and extensive fossil lists given. These terrigenous beds
are the same as those called ‘‘Temblor’’ by F. M. Anderson.
The Temblor is considered the equivalent of the Vaqueros of the
coast because of ‘‘the large number of species common to the
two’’ (p. 87).

The ‘‘Monterey shale’’ is considered to be probably absent,
although it is stated that the ‘‘ Big Blue’’ referred to the Mon-
terey by F. M. Anderson ‘‘corresponds in stratigraphic position
to the Monterey shale (middle Miocene) of regions near the
coast, but nothing has been discovered to indicate that it may
belong to that formation’’ (p. 76).

Cantua-Panoche District, R. Anderson, 1910—A brief state-
ment of the geology to the north of the Coalinga district, in the
Cantua-Panoche region, was given by Robert Anderson in Con-
tributions to Economie Geology, 1909.°%% Under the caption
‘‘Lower Miocene’’ (pp. 64 et seq.) is deseribed ‘‘the continu-
ation of that described as the Vaqueros sandstone (lower Mio-
cene) in the report of the Coalinga district.’’ The fauna in
the hills surrounding the Vallecitos (30-35 miles north of Coal-
inga) is said to differ in aspect ‘‘from that in the Coalinga dis-
trict or from any other well known fauna of the Coast Ranges.
This fauna, together with the presence in the formation . . . of
considerable masses of siliceous diatomaceous shale, which occurs
only in thin zones in the northern part of the Coalinga district
and is absent in the southern part, suggests a possible equivalence
of the formation to the lower portion of the Monterey shale in
the region nearer the coast and a gradual transition westward
from the sandy and gravelly strata at the eastern edge of the
Coast Range to the purely organic sediments in the coastal belt.’’
The fauna is said to be characterized by such forms as Turritella
ocoyana, Pecten andersoni, P. propatulus, and teeth of Desmo-
stylus, which would seem to place it in the 7. ocoyana zone or F.
M. Anderson’s Temblor. Robert Anderson remarks that ‘‘ Any
correlation of sandy fossiliferous strata with the Monterey shale
is difficult to make, owing to the scant knowledge of the fauna
of Monterey time. Hence the suggestion of the possible equiv-
alence of the formation to the lower part of the Monterey shale

68 U. S. Geol. Survey, Bull. 481—-A, pp. 54-83, 1910.

1913 | Louderback: The Monterey Series 221

is conjectural.’’ The beds are said to be 1700-1800 feet thick
around the Vallecitos and to consist of sandstone and conglom-
erate interbedded with thick lavers of siliceous diatomaceous
shale.

McKittrick-Sunset Region, Arnold and Johnson, 1910.—A
discussion of the territory to the south of the Coalinga district
is contained in the ‘‘Preliminary report on the MceKittrick-
Sunset Oil Region’? (1910) by Arnold and Johnson.*? The

‘*Vaqueros sandstone (lower Miocene) ’’ is described as for the
most part uniformly arenaceous, but near Annette and upon
the southwest side of the Carrizo Plain the sands evidently in
part grade into light colored shales closely resembling the Mon-
terey®® (p. 48). It is given as from 60 to 2400 feet thick. These
are of course F. M. Anderson’s ‘‘Temblor beds.’”’

The ‘‘Monterey shale (lower middle Muiocene)’’ in which
F. M. Anderson and others had included ‘‘the whole of the
prominent series of white shale extending uninterruptedly from
just east of Polonio Pass southeastward along the flank of the
Temblor Range nearly to Temblor ranch, and to the great area
of shale embracing practically all of the range from the head
of Salt Creek southeast to the limits of the region studied,’’ was
separated into two formations, ‘‘one of which is thought to be
the equivalent of the Santa Margarita (?) formation (upper
middle Miocene) in the Coalinga region, while the earlier more
closely resembles the Monterey (lower middle Miocene) as_ it
has been described in other parts of the state. Definite palaeon-
tologic evidence for the separation in the MeKittrick-Sunset
region has been seant. . . . The main consideration involved in
the present separation of the rocks, however, is one of convenience
to the prospector. Since there is a marked difference in the
physical appearance of the rocks, it simplifies an understanding
of the geologic and structural conditions’? . . . (pp. 55-56).

““The lowest portion of the series is usually made up of
calcareous and arenaceous shales which represent a transition
into the sandstones and fossiliferous beds of the Vaqueros. These
grade upward into typical siliceous and argillaceous shales that

69 U.S. Geol. Surv. Bull. 406 (1910).

70 Italics not in original.

ape University of California Publications in Geology [Vou.7

contain evidence of organie origin. Prominent zones of nodular
caleareous shales are characteristic of this middle portion of the
series. The upper third of the formation includes an indefinite
zone of sandstone beds that are irregularly intercalated in limy-
siliceous shales. The succession and character of these sedi-
ments coincides very closely with those of the lower division of
the Monterey in the Santa Maria district. The upper division,
so prominently developed near Lompoe, in the Santa Maria dis-

trict, is absent from the MecKittrick-Sunset region, unless the |

basal organic shales of the formation here described as Santa
Margarita (?) formation are the same as those described as upper
Monterey in the Santa Maria report’’ (pp. 56-57).

The Vaqueros and Monterey together are given as conform-
able, but with supposed uneonformable relations to the over-
and underlying formations. We may be sure that the Monterey
series is represented here, and that it shows many similarities
of depositional progress to that of the Southern Coast Ranges.
Evidence for age and divisions as given does not appear to be
particularly good in the area studied, but the attempted discrim-
inations are made on the basis of ideas developed elsewhere.

Geologic Record of California, J. P. Smith, 1910.—In the
‘“Geologie Reeord of California’? (1910) a summary by J. P.
Smith,? a geologie column is presented exhibiting a standard
marine section for the Coast region of which the Tertiary part
is as follows :*°

71 Jour. Geol., vol. 18, pp. 216-226 (1910).
72 Loc. cit., plate following page 217.

1913] Louderback: The Monterey Series 223

FORMATION

/Sandstones of Lake Merced with
| Merced | Cardium meekanum and Scutella
| interlineata

Pliocene $$ —-
| Sandstones of San Di-
Hes ; ON ot ego and Half Moon
S: r 2 sime ; 4

San Diego Purisima | Bay with Pecten

| healeyi

| |Sandstones of San Pablo Bay and
Upper San Pablo | the Coalinga region, with Pecten
| pabloensis and Peecten oweni

Sata 'Sandstones of Salinas Valley, with

Dae > o ite
Margarita Pecten estrellanus, Ostrea titan,
: ; and Tamiosoma gregaria
Miocene Middle =a | a aaa ee
| 1M rey Shales wi di
leMionteresar | fonterey Shales with Peeten discus
| ~ | and Peeten peckhami
Sandstones of Monterey and San
. is is e les, wit -
Lower Vaqueros Luis Obi po counties, with Tur
ritella inezana and Mytilus ma-
thewsoni
}--——— — =
| |
: . | Sandstone d shales
Oligocene Astoria ISan Lorenzo| "2ndstones and shales

| of Santa Cruz County

ae |Sandstones of Ft. Tejon, Martinez,
Claiborne Tejon and Mereed Falls with Veneri-
cardia planicosta

Kocene

Midway | Martinez

| ai ae
| Sandstones of Martinez with Pho-
| ladomya nasuta

In a later table™* he gives the faunal zones, and their oceur-
rence at various localities. He recognizes a lower ‘‘ Vaqueros’’
zone (‘‘zone of Pecten magnolia and Turritella inezana’’), and
an upper ‘‘ Vaqueros’

zone (‘‘zone of Agasoma and Pecten an-
dersoni’’), including the Turritella ocoyana zone and the Temlor
beds of the interior districts.

Throughout runs the fallacy that the Monterey and Vaqueros
each represent a definite time interval and a life-time zone. The
untenability of some of the division lines here given has already
been discussed, some of the others will be taken up later.

Sargent Oil Field, Jones, 1911.—Early in 1911 W. F. Jones
published a description of ‘‘The Geology of the Sargent Oil
Field’’™* at the southeastern end of the Santa Cruz Mountains

73 Not numbered, but just in front of p. 226.

74 Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, no. 3, pp. 55-78, Feb. 18,
LOI.

224 University of California Publications in Geology | Vou.7

just north of Pajaro River. He recognized a ‘‘ Miocene Series’’
lying uneonformably above the Franciscan and unconformably
below the San Pablo. He divided it ‘‘on lithological grounds”’
into a lower portion chiefly sandstones (1500 feet), which he
said is ‘‘probably of Lower Miocene age,’’ and an upper, chiefly
bituminous shales with occasional limestones (3000 feet), called

‘‘Monterey Shale.’’ The former is deseribed as ‘‘very similar
to the Temblor beds of the Monte Diablo range described by
F. M. Anderson.’’ ‘‘There are several thick beds of siliceous
shale in the terrane which has tentatively been called Lower
Miocene, but the presence of large amounts of sandstone, clay
shale and conglomerate distinguish it from the overlying Mon-

terey.’’ The upper shales (‘‘Monterey shale’’) are said to le
conformably on the lower beds, and at two localities overlap the
latter (as is normal for a conformable series) and he directly
on diorite or Franciscan sandstone. It is evident that the rela-
tions described are typical of the Monterey series throughout
most of the coastal part of the province.

Kern River Region, PF. M. Anderson, 1911.—In November,
1911, F. M. Anderson*® published ‘‘The Neocene Deposits of

Kern River, California, and the Temblor basin. He describes
the representatives of the Monterey Series in the Kern region,
on the east side of the southern San Joaquin Valley, under the
heading ‘‘Temblor*® Group, which he divides into a ‘‘ basal mem-
ber,’’ 350-600 feet thick, and an ‘‘upper member,’’ 1260 feet
thick. He deseribed the basal member as essentially sandy.
‘“Some of the lower beds consist largely of voleanic ash, pumice,
and sand. ... Basal conglomerates are visible in only a few
places, but a stratum of at least 50 feet is exposed at one point
north of the Kern River’’ (pp. 90-91).

‘

The upper member ‘‘contains a smaller percentage of sand

and other detrital matter, and a greater percentage of organic

material than any other portion of the Neocene. And of the

detritus present a great portion is of clay and shaly matter.”’
75 Proc. Cal. Acad. Scei., 4th Ser., vol. III, pp. 78-148 (1911).

76 Anderson renewed his attack on the legitimacy of the term Vaqueros
as explained above, and insists on the use of Temblor. Footnote, p. 106.

1913] Louderback: The Monterey Series 225

‘‘In this member clays and shales probably form in the out-
crop about 50 per cent of its volume, and of this percentage about
one-half is organic. Some layers are chiefly composed of diato-
maceae and other minute organisms’’ (p. 92).

He gives fossil lists as collected from three ‘‘zones,’’ A, B,
and C, and these lists include forms already familar on the west
side. ‘‘As will be seen the faunas of the three prominent zones
already described belong to the lower division of the Neocene,
and are characteristically Lower Miocene. The upper division
as far as known is almost without fossils, and is barren of any
forms that are serviceable for stratigraphic correlation’’ (p. 102).

As for the lowest zone (A), ‘‘It was at first thought that this
horizon might prove to be older than the typical Temblor, on
account of the number of large pecten species it contained, but
there is now quite abundant proof that a horizon older than the
Temblor has not been recognized either here or in any part of
the Temblor basin. . . . It may be supposed that the occupation
of the Temblor basin by the sea was transgressional and pro-
gressive and that there are older beds belonging to the Neocene
in the outer coast ranges; but if this is true it has yet to be
shown’’ (p. 107).

In regard to zone B, he said ‘‘ Any question which may arise
as to its exact stratigraphic position is more likely to involve
only a choice between the Temblor and the Monterey. But thus
far in the study of the West Coast Miocene, the Monterey has
not been regarded as the habitat of such species as Agasoma
gravidum, Turritella ocoyana, Cytherea mathewsoni, Dosinia
whitneyi, Yoldia impressa and a score of other species given in —
the lists... . And furthermore it must be added that while
Zone B is rich in species, some of which have often been found
in the Monterey shales, the species most widely characteristic
of the latter, namely Pecten peckhami, has not been found at all
in any part of the Kern River area’’ (p. 107).

It is hard to see how this is a point against its ‘‘Monterey’’
age, seeing that P. peckhami has been found farther west in
rocks lying below the ‘‘ Vaqueros’’ or ‘‘Temblor’’ and considered
by Arnold, R. Anderson, F. M. Anderson and others, Eocene or

Oligocene, as well as in the latest ‘‘Monterey shales.’’ It can

226 University of California Publications in Geology [Vou.7

only mean a peculiarity of geographical distribution of the
species.

The mixture of faunal elements previously supposed charac-
teristic of Monterey and Vaqueros respectively may be related
to the mixture of depositional types—bands of diatomaceous
shales with intervening sandstones, as in western Contra Costa
County. If there really are life-time zones in the Monterey
series, it may mean a transitional fauna. In either ease it shows
the imaginary character of the supposed time independence of
the two formations ‘‘ Monterey shale’’ and ‘‘ Vaqueros sandstone”’
or ‘‘Temblor beds.’’

But Anderson takes a different view and says ‘“‘It is quite
impossible to recognize in the outcrop in any part of the Kern
River area that member of the Miocene which forms its most
characteristic feature in many parts of the Coast, that is, the
Monterey Shales.’’

‘In the series as described in the preceding pages, . . . there
is one portion that bears some resemblance to the Monterey,
namely, that portion which is most strongly characterized by
shales, some of which are organie to a considerable extent. It
will be noticed that nearly every class of materials commonly
found in the Monterey has been found in the upper part of the
Temblor group’’ (p. 109). This statement is very interesting
when we consider that the actually applied criterion for the
‘‘Monterey’’ has everywhere been the ‘‘materials . . . found in
the upper part of the Temblor group.”’

‘But if this collection of strata really represents the Monte-
rey, it is hardly comparable in thickness or character to known
exposures of Monterey not far away.’’ It may be pointed out
here that the change from McKittrick to the Kern is hardly
quicker or more marked than the change from McKittrick to-
wards Coalinga.

‘*Temblor Basin.’’—Anderson brought out some very import-
ant relationships when he showed that the Kern River deposits
on the edge of the Sierra Nevada and the deposits along the
west side of the San Joaquin Valley about Coalinga and north
are along the borders of what I consider the interior portion of
the basin of deposition during Monterey time and what he calls

1913 ] Louderback: The Monterey Series 224

the Temblor basin. Along this eastern border region the rocks
developed are chiefly terrigenous while the ‘‘Monterey’’ (by
which of course he really means an upper diatomaceous member,
although he evidently has in mind an ideal time interval) ‘‘is
either absent, or is present in a reduced or disguised form’’—
“disguised form’’ is, I believe, a very appropriate expression.

““The explanation of this interesting fact is to be found no
-doubt in the diastrophie record of the times. The subsidence
that inaugurated the occupation of this basin by Temblor sedi-
ments continued without interruption until middle Miocene time.
It then paused, and on the eastern and northern borders of the
basin the shore lines remained stationary throughout the epoch
of the Monterey. In these parts, therefore, sedimentation was
nil, while along the western borders subsidence went on without
cessation, and sedimentation was therefore continuous.’’

‘*Tt is unnecessary to suppose that there was any elevation
and denudation of the older Miocene during the Monterey epoch,
either in the Kern River area or elsewhere, and no such dis-
turbance seems probable. The facts appear to indicate merely
an epoch of stability along the eastern and northern shore lines
of the basin, along which, therefore, the conditions were unfa-
vorable for the continued accumulation of any class of sedi-
ments’’ (pp. 110, 111). He also considered that the climates of
the Temblor and Monterey epochs were different, the diatoma-
ceae, foraminifera, gypsiferous strata and lack of terrigenous
sediments, in the latter, indicating an arid climate (p. 111).

The writer inclines towards a simpler explanation than the
one given by Anderson, which requires the interior edge of the
basin to sink only during lower Miocene and to stop sinking
in middle Miocene while the depression of the coastal portion
continued. It looks very much like the result of simple pro-
gressive subsidence with minor oscillations. In the gradual trans-
gression of the sea, terrigenous sediments (generally sandy or
pebbly) were almost everywhere laid down and only with in-
creasing depth and distance from the shore line do we get organic
deposits. Naturally the edges of the basin when at its period
of greatest areal extent must have been in the littoral zone and
could have received only terrigenous or chiefly terrigenous de-

228 University of California Publications in Geology [Vou.7

posits whatever part or portion of the whole Monterey time they
represented. The arguments for marked change in climate do
not appear to apply particularly, for unless the volume of silt-
laden water discharged from the land had been comparatively
small there could not have been such pure diatomaceous materials
deposited at any portion of the period so close to shore as we
know them to have been throughout the whole province, and
this applies to the lower as well as the upper portions of the
series. The evidence favors an arid climate throughout.

South End San Joaquin Valley, R. Anderson, 1912.—In the
spring of the present year (1912) Robert Anderson published’
a ‘‘Preliminary Report on the Geology and Possible Oil Re-
sources of the South End of the San Joaquin Valley’’—the
region lying along the mountain flanks between the McKittrick-
Sunset area and the Kern River region just discussed. He says
‘Although great differences in thickness and details of litho-
logic character occur, the similarity is sufficient to show that the
major features of the Tertiary geologic history were alike on
the two sides of the valley... .’’ ‘‘In the Temblor Range field
the lower division corresponds to the Vaqueros sandstone (lower
Miocene), the middle one to the Monterey shale, and the similar
shale of the Santa Margarita (?) formation (middle Miocene) ’’
(oad)

A most interesting relationship is brought out in the statement
that ‘‘At the south end of the valley the formations of the
Temblor Range continue into the San Emigdio region, with
changes, however, that alter the section considerably, especially
in the lower and middle divisions. . . . A significant change is
the decrease in the exposed thickness of the organic shale from
several thousand feet in the Temblor Range to about 1000 feet
in the San Emigdio region, and its gradation into a less diato-
maceous and more clayey and sandy type of shale. Whether
this is due to the fact that a smaller volume of the organic
sediment was deposited here, or to its having been partly eroded
in this region, owing to its nearness to the zone of uplift repre-
sented by the granite mountains, or to its being hidden in part

77 U. S. Geol. Surv. Bull., 471-A, pp. 102-132 (April, 1912).

1913 ] Louderback: The Monterey Series 229

by uneonformably overlapping formations has not been deter-
mined. The character of the material composing the Miocene
section gives some weight to the belief that the greater prox-
imity of this area to the mountain belt caused a nearer approach
to shore line conditions and the deposition here of coarser sedi-
ments in place of part of the purely organic deposits of the
Temblor Range’’ (p. 116).

The deposits here described are on the north side of the
mountainous area to the south of which the rocks of the Santa
Clara region were deposited, and the great increase in terri-
genous material on their approach from the south has already
been described.*®

There seems no reason to doubt that much if not all of the
earthy shale and sand of the San Emigdio region is econtempor-
aneous with the biogenic shales to the north and west. Ander-
son’s description supplements well the study on the south side
of the mountains, connects the Sunset and Kern regions, and
indicates the general position of the extreme shore line of the
Monterey epicontinental sea.

Miocene Invertebrate Fossils, J. P. Smith, 1912.—Professor
J. P. Smith has recently published a general statement’? of the
“Geologie Range of Miocene Invertebrate Fossils of California,’’
in which he takes a stand on the Miocene faunas quite at vari-
ance with his former views and those of Anderson, Arnold and
others, but much more in harmony with the stratigraphie conelu-
sions of the present paper.

He says: ‘‘Later writers . . . have introduced a much more
elaborate classification of the Neocene of California, and a large
number of formation names. But these so-called formations,
however useful they may be for areal mapping and for economic
geology, do not always correspond to faunal divisions. Some
of them are merely different facies of the same thing.’’

‘““Tnstead of the numerous subdivisions recognized by most
stratigraphers, there are, in fact, only two major faunal units
in the Miocene of California: a lower, including all the faunas
up through the Monterey ; and an upper, including the San Pablo,

78 Part I of this paper, pp. 187 and 188.
7 Cal. Acad. Sei. Proe., 4th Ser., vol. III, pp. 161-182, April, 1912.

230 University of Califorma Publications in Geology (Vou. 7

Santa Margarita and Etchegoin faunas. The division line be-
tween them corresponds to the period of orogenic activity that
came on at the end of the Monterey Epoch. . . . This brings us
back almost to the standpoint of Lawson and Merriam, who have
proposed to call all the lower Miocene ‘Monterey’ and all the
upper Miocene ‘San Pablo’’’ (pp. 162-163). In his lower
‘““major faunal division’? Smith includes two subdivisions:

( Monterey—Temblor faunas of the Contra Costa hills, Mt.

| Hamilton Range, Black Mountain, Santa Lucia Range,
Coalinga region, Bakersfield region, Santa Ynez and Santa
Monica mountains, and Santa Ana Range

Vaqueros fauna, of the Santa Lucia Range, Black Mountain,

| the Santa Monica and Santa Ynez mountains.

Lower.

These two faunal subdivisions as judged from the faunal
lists given correspond exactly to the faunal stages suggested by
Merriam in 1904:

FAUNAL ZONES
Merriam, 1904 Smith, 1912
Zone of T. ocoyana .
Agasoma zone (and T. variata) , Monterey-Temblor
(Lower Lower faunas

: 5 ; ; : Miocene
Miocene) Zone of T. hoffmanni Vv f
eS T. jnezana ) aqueros aunas

In regard to the Temblor, Smith says: ‘‘In the check-lst
the Temblor and Monterey faunas are entered separately as a
matter of record, although they are certainly synchronous”’
(p. 169). As to the Vaqueros, ‘‘the lowest horizon of the Mio-
cene has been called by Merriam the zone of Turritella hoffmanni
(= Turritella inezana) ; it may eventually be found to be the
inshore equivalent of the deep-water San Lorenzo Oligocene, with
which it has a few species in common’’ (p. 165).

While Smith uses the well known terms Vaqueros and Mon-
terey

and without any particular explanation of a changed
definition—he does not use them in the- sense in which anyone
else has previously used them. It is quite probable that he
is right in his division of the littoral fauna of the Monterey
series into the two zones proposed, but he has applied to them
two formation names—names for formations which do not really

1913] Louderback: The Monterey Series 231

exist as such. It would be impossible in any locality to draw
the actual line in the field between the beds corresponding to
one zone and those corresponding to the other, unless there
were a wholly terrigenous series well supplied with zonally
characteristic fossils. If a diatomaceous shale came in between
two sandstones, one with forms of the lower zone and the other
the forms of the upper zone, it would be impossible to tell to
which zone the shale belonged.

It is a fact that the fossils given by Hamlin for his Vaqueros
formation belong to the Vaqueros fauna of Smith. But in the
““type’’ locality the distinction between ‘‘ Vaqueros sandstone’’
and ‘‘Monterey shale’’ was admittedly on a lithologie basis, and
who can say that the ‘‘Monterey shale’’ in part of that area
does not represent the ‘‘Vaqueros fauna’’ life period, or that
the ‘‘Vaqueros sandstone’’ of other parts of the area does not
represent the ‘‘Monterey-Temblor fauna’’ life period?

As long as the Monterey series cannot be separated into two
(or more) formations of any general validity, but only locally
into lithologic types that vary rapidly in their thickness and
the horizon of their gradation zones, it seems artificial, unnec-
essary and confusing to label the faunal subdivisions or stages
with formational names. The only logical course is to give the
faunas faunal names, as has been done by Merriam.

As soon as the sense in which Smith uses the terms Vaqueros
and Monterey-Temblor is clear it is easy to see that in but few
places where those terms have been applied will the division lnes
or correlations of other geologists agree with his subdivisions.
Furthermore, in most of those fields no one could actually draw
the lines representing his divisions.

The most noteworthy discrepancies are in the San Joaquin
Valley region, where Arnold, F. M. Anderson and their asso-
ciates have correlated the terrigenous sediments of the Monterey
series (Temblor of Anderson) with the Vaqueros. As pointed
out already, the indications are that they are in large part con-
of these authors—

939.

temporaneous with certain ‘‘ Monterey shale
and as no higher fauna is found there than that of the 7. ocoyana
zone, and as the type ‘‘ Vaqueros’’ was originally reported to
contain fossils of the 7. hoffmanni zone, Smith’s reference of

232 University of California Publications in Geology (Vou.7

these beds to the Monterey rather than to the Vaqueros is evident.

San Jose and Mt. Hamilton Quadrangles, Templeton, 1912.—
At the April, 1912, meeting of the Cordilleran Section of the
Geological Society of America E. C. Templeton presented a paper
on ‘‘The General Geology of the San Jose and Mt. Hamilton
Quadrangles,’’’® in an abstract of which he says: ‘‘The lowest
Miocene sandstone belongs to the Temblor phase of the Mon-
terey series and rests unconformably on the Franciscan. . . It
has an abundant fauna, typically Temblor. Its thickness is
about 1000 feet. Overlying it is the Monterey shale, hard, light-
colored, and siliceous, with a thickness of about 1200 feet... .
The Monterey shale is overlaid, apparently conformably, by a
thickness of about 3500 feet of sandstone with a typical Temblor
fauna.’”’

It is evident here that ‘‘Monterey shale’’ is used merely in
the sense of a depositional facies, and ‘‘Temblor’’ is used in a
faunal sense. The relative position of beds is instructive.

Kirker Pass, Clark, 1912——The Monterey section of Kirker
Pass, north of Mount Diablo, has recently been described by
Bruce Clark.8! The fossils found in the upper part of the section
are referred to the upper Monterey.

PART III

GENERAL CONCLUSIONS
GENERAL DESCRIPTION OF MONTEREY SERIES

MONTEREY SEDIMENTS

General Distribution.—The Monterey series (including such
local divisions as have been called Vaqueros, Monterey shale,
Modelo, Puente, Temblor, ete.) is a natural stratigraphic unit.
It represents a eycle of sedimentation in the geologic history of
the Pacifie Coast, which has produced one of the most important
and widespread series of deposits in the California region.*?

so To be published Geol. Soe. Am. Bull., vol. 24. Abstract.

81 Univ. Calif. Pub. Bull. Dept. Geol., vol. 7, no. 4, Oct. 10, 1912.

s? The Monterey province is not limited to California, although it has
been more extensively studied there.

1913 | Louderback: The Monterey Series 233

As reviewed in the preceding part of this paper, it occupies
considerable areas in the territory commencing about Point Arena
(Lat. 39° N.), embracing the Coast Range region from the ocean
_to the San Joaquin Valley southward to the Tehachapi Moun-
tains and beyond in Ventura, Los Angeles, and Orange counties,
and the channel islands (about Lat. 33° N.); and extending
eastward across the Great Valley into the foothills of the Sierra
Nevada from the Tehachapi region north to the vicinity of Deer
Creek, a few miles south of Porterville.**

Progress of Sedimentation—The Monterey series represents
an invasion of the sea from the west or southwest with a
gradual and progressive subsidence, the advaneing shore line
being marked almost everywhere by sands, often gravels, gen-
erally well supplied with a characteristic littoral fauna.** With
the progress of the subsidence and migration of the shore line
inward, the character of sedimentation at any one point grad-
ually changed—naturally in some places more rapidly than
others, depending on the character of the shores and whether
near larger or smaller stream mouths. It first became finer and
assumed the form of terrigenous muds, then showed more and
more admixture of organic material. The organic material was
commonly at first preponderatingly calcareous (limestone and
calcareous shale), but ultimately siliceous, and wherever any
territory became far enough removed from the areas of terrig-
enous sedimentation the material became entirely organic (fre-
quently more or less admixed with pyroclastic material) and in
time produced those pure diatomaceous earths and shales for
which the Monterey series is famous.

In some localities areas are found where the first sediments
deposited on the older rocks were earthy shale or of organic
origin. These may in part be explained as hills, mesas, ridges
or other areas of higher ground, particularly if rather flat sur-
faced, which while the main shore line was migrating past them
were comparatively small islands or peninsulas, and which later

83 See Anderson’s map.—Proc. Cal. Acad. Sei., 4th Ser., vol. IIE (1911),
Plate III, opp. p. 126.

84 Tabulated by Smith in Proe. Cal. Acad. Sci., 4th Ser., vol. III, pp.
161-182 (1912), as ‘‘Lower Miocene Fauna’’—the fauna of Merriam’s
Agasoma zone.

234 University of California Publications in Geology [Vou.7

subsidence quickly immersed in comparatively deep water—or
at least far enough from the main shore to receive no earthy
deposits.*° Or certain elevated tracts might have been protected
in places from direct wave action by lying behind some head-
land or within some embayment. In such inlets there may have
been river-born detritus with deposits largely of very fine grain
(later becoming shale). Or there may have been no main streams
emptying into some of them, and only a meager supply of terrig-
enous detritus. Some areas may represent Dixon’s lagoon type*®
of sedimentation. But whatever their origin, it should be noted
that they are the exceptional type, and even some areas that
have been so reported have proved on more careful examination
to show at least a thin sandy base to the series.

Effect of Geographical Conditions—Many phenomena of dis-
tribution and lithologic character indicate that the series was
deposited over much of the province on an uneven topography,
with many hills and mountainous ridges protruding above the
water level and some of these remained above sea-level during
the period of greatest depression (or greatest extent of water
surface) and gave an archipelagic character to the epicontinental
sea. These land masses did not in general carry large streams
capable of contributing terrigenous sediments to a considerable
area beyond the immediate shore line, and therefore the total
thickness of the series and the relative proportions of terrigenous
and non-terrigenous material varied rapidly in some loealities
from point to point.

The greatest thicknesses of siliceous earths are found near
the central and seaward portion of the depositional areas out-
lined: in the Santa Maria-San Luis-Monterey region along the
coast, where they are said to reach 6000-8000 feet in thickness,
and from here directly toward the interior across the present
ranges into the hills bordering the great valley on the west in
the vicinity of McKittrick and the Temblor range. This forms
an area that projects from the coast into the interior while

85 Some of the areas which at first glance seem to have this relation-
ship have been given this appearance by post-Monterey faulting, the

siliceous shales being so displaced as to outcrop against the pre-Monterey
formation.

86 Quar. Jour. Geol. Soe., vol. 67, p. 511 et seq. (1911).

1913 | Louderback: The Monterey Series 235

eradually narrowing—a gulf-like embayment representing in a
general way the deepest and most detritus-free portions of the
Monterey epicontinental sea during its period of maximum land-
ward extension.**

As we approach the ultimate shore line, in the San Joaquin
Valley environs, and against the projecting mountain masses
along the coast, the terrigenous sediments predominate, some-
times to the complete absence of the siliceous shales.

Depositional Oscillation—The change from coarse to fine
terrigenous sediments and then to non-terrigenous was not every-
where an unbroken progression. It is most simply developed
in the Monterey-San Luis-Santa Barbara region along the present
coastal area and in its immediate interior over towards the
MeKittrick and Temblor range region. Many localities show
oscillations from sands or clays to siliceous ooze and back again
to sands or clays. These areas are particularly those near per-
manent or long enduring land masses of Monterey time. They
may indicate an oscillatory movement of subsidence, by which
small retrogressive stages occurred at intervals during the general
movement of depression—a type of action for which we have
evidence at other times and places; or they may be the result
of climatic changes, greater volumes of sediment being discharged

87 Professor J. C. Branner at the recent meeting of the Cordilleran
Section of the Geological Society of America put forward an ingenious
theory to account for the great thicknesses of aiatomaceous earths in the
Monterey. He considered that the diatoms, naturally thriving in cold
water, were floated along by the ‘‘marine currents that flowed southward
from Alaska.’’—‘‘Onee within the zone of islands’’ (of the Coast Range
archipelago) ‘‘these floating materials were probably driven into the
cul-de-sac at the lower or southern end of the present San Joaquin Valley.
Materials carried at or near the surface of the water could not escape,
if, as is assumed, the embayment was fairly well closed at the extreme
southern end. it is exactly here, and around the southwestern corner of
the San Joaquin Valley, that the deposits of diatom skeletons are thick-
est.’’ (To be published Bull. Geol. Soe. Amer., vol. 24.) It is quite
probable that the marine currents had an influence on the life and dis-
tribution of the diatoms, but the distribution of thickest diatomaceous
deposits as outlined by the writer in describing the California gulf of
Monterey time seems to be entirely accounted for by its relations to the
ultimate shore line and to the border of thick terrigenous sediments to
its northeast, east, and southeast (the limits of Anderson’s Temblor
basin). Furthermore, these thickest diatomaceous deposits extend to the
coast of the open ocean in the San Luis-Santa Maria-Lompoe region, and
even the thinner deposits to the north (and south as well) can likewise
often be brought into definite relationship with recognizable shore
features which determined depth of water and sediment supply.

236 University of Califorma Publications in Geology [Vou.7

during some stages than at others, and therefore spreading over
larger areas ; or both such agencies may have ‘been active.

As examples of such areas may be mentioned the country
to the north of Santa Clara Valley, the Los Angeles district, the
southern end of the San Joaquin valley, the Vallecitos, the Mount
Diablo region of Contra Costa County, and the Point Arena area,
already discussed in parts one and two of this paper.

Chert.—Instead of diatomaceous earths or shales, the siliceous
members of the Monterey often appear as cherts—chiefly opaline
in character. They are generally vellowish, but sometimes brown
to nearly black. The dark color is usually due to bituminous
substances. Sometimes these cherts occur in thin beds one to
several inches thick, interstratified with earthy or siliceous earthy
shales, the alternation being repeated hundreds of times.**

Relation to the Occurrences of Petrolewm.—tThe siliceous and
the earthy shales of the Monterey series are very commonly bitu-
minous, and are looked upon by most of the geologists working
in the California oil fields as the source of most of the commer-
cially utilizable petroleum of the state. Seepages and brea de-
posits are often associated with them. As far as the supplies
of oil for industries is concerned, it is commonly derived from
the sands of the series (the basal sands, or higher sands inter-
calated in the shale series), sometimes from zones of brecciated
chert, sometimes from the sands or other porous rocks of ad-
joining formation groups, stratigraphically either higher or lower
—from Mesozoic to Pliocene.

VOLCANIC PRODUCTS IN THE MONTEREY SERIES

Tufis.—Besides the terrigenous and biogenic deposits men-
tioned above, products of voleanic activity are frequently encoun-
tered within the Monterey Series. Over considerable areas ash
beds are more or less common and at different horizons. Along
the hills stretching from Lion Rock, near San Luis Obispo, to
north of Santa Maria, about 30 miles, a layer of voleanie ash
occurs, in part carrying coarse glass fragments, In part pumi-
ceous, in part coarsely agglomeratic, which according to Fair-
banks is rhyolitic and reaches a maximum thickness of 800 feet.

88 Well shown in halftone, plate 11, opposite p. 365, Bull. Dept. Geol.
Univ. Calif., vol. 2.

1913] Louderback: The Monterey Series Zar

The writer has seen similar tuffs probably of the same horizon
in the vicinity of the Santa Ynez River. Light colored tuffs
(sometimes definitely stated to be rhyolite tuffs) have also been
found along the coast about Point Sal, to the north of San Luis
Obispo, and in the vicinity of Monterey, in Contra Costa County,
the Mount Diablo region and Santa Catalina Island, and have
been reported from the interior at various points as far east as
the flanks of the Sierra Nevada in the Kern River region. Be-
sides its occurrence in definite layers or beds, ashy material
(mineral grains and glass fragments) is frequently found dis-
seminated through the diatomaceous earths and shales.

Lavas.—Rhyolitie lavas have been reported from the San
Luis region. Basie lavas are quite widespread, varied and in
some places abundant. Fairbanks has described pyroxene-ande-
site, quartz-basalt, olivine diabase and augite-teschenite from
the San Luis region. Other localities where basic voleanies, ex-
trusive or intrusive, are known in this series, are about Point
Sal, in the Santa Maria district, the Santa Monica mountains
(a thick series of lavas and breccias and associated intrusives),
Carmelo Bay, and the mountains bordering Carrizo plains (espec-
ially abundant in the southern portion, where large intrusive
masses occur, some of which have produced considerable meta-
morphism in the shales). Mr. G. C. Gester’® has observed abun-
dant andesitic and basaltic volcanics associated with the Monterey
series in the hills about the southwest extremity of the San
Joaquin Valley. The voleanics of San Clemente and Santa
Catalina islands may also belong to this series.

LIMITS OF THE SERIES

The upper limits of the Monterey Series are in all places so
far studied marked by an unconformity—generally angular.
The orogenic movements that took place at the end of the Mon-
terey period of deposition were important and widespread, the
next oldest succeeding formation being the San Pablo (and its
supposed correlatives, the Santa Margarita, ete.), considered by
some to correspond to the upper Miocene and by others to the
Pliocene. The lower limits of the series are generally also dis-

89 Personal communication, Aug., 1912.

238 University of California Publications in Geology [Vou.7

tinetly determined by an unconformity, the underlying forma-
tions ranging from crystalline terranes (Mesozoic or even Paleo-
zoic) up to the Tejon (generally accepted as upper Eocene) and
the Sespe (considered Eocene or Oligocene). In some areas,
where no angular deformation took place, the separation from
the Tejon appears to be difficult if the beds near the border are
not fossiliferous. The general relations, however, and the con-
tributory palaeontologic evidence indicates that there was a dis-
tinct discontinuity of conditions between the Tejon and the
Monterey, and that there were orogenic movements and a general
recession of the sea between those two periods of deposition.

The relation of the Monterey to the San Lorenzo (referred
by Arnold to the Oligocene) is uncertain. These latter beds
have not been definitely recognized outside of the Santa Cruz
Mountains, where they are said®® to lie ‘‘in general conformably
below the Vaqueros sandstone’’ (p. 4, col. 1). And again, ‘‘In
this body of water limestone of the Eocene age, the Butano sand-
stone (supposed Oligocene), the San Lorenzo shale (Oligocene),
and the Vaqueros sandstone (lower Miocene) were deposited, all
(except possibly the Eocene) in conformable*! sequence’’ (p. 10,
col. 3). J. P. Smith has recently suggested®? that this ‘‘lowest
horizon of the Miocene,’’ the Turritella hoffmanni (or inezana)
zone, ‘‘may eventually be found to be the inshore equivalent of
the deep-water San Lorenzo Oligocene, with which it has a few
species in common.’’ In this case the Butano sandstone would
probably be the base of the Monterey series for that region. It
will require further investigation in the field to satisfactorily
settle the question.

PALAEONTOLOGIC CHARACTERS
Fauna.—The fauna of the Monterey series is, at least for the
inshore facies, quite distinctive, and with any reasonable devel-
opment of fossils in the coarser terrigenous beds their proper
assignment to the Monterey period is assured. Professor J. P.

90 U. S. Geol. Surv. Santa Cruz Folio, California, no. 163 (1909).

91 Notwithstanding these definite statements in the text, in the col-
umnar section and in the map legends of the folio cited, an unconformity
is indicated between the San Lorenzo and the Vaqueros.

92 Proc. Cal. Acad. Sci., 4th Ser., vol. 3, p. 165 (1912).

1913] Louderback: The Monterey Series 239

Smith has recently published most convenient lists of the inverte-
brate fauna of the Monterey series in his ‘‘Geologie Range of
Miocene Invertebrate Fossils of California’’ under the desig-
nation of ‘‘lower Miocene’’ faunas.** The reader interested in
the palaeontologie data is referred to this useful paper, and no
attempt will be made to present a faunal list here.

As for the offshore (shale) fauna, it is meager and appar-
ently not so characteristic, and references of shale—especially
siliceous shale—facies to the Monterey series have to be made
with eare, and either with regard to their association with char-
acteristically fossiliferous sandstone, or to their inelusion within
the limits of the sedimentary series of rather characteristic habit,
between the unconformities already described.

Faunal Stages——There appear to be at least two** widely
recognizable faunal stages in the Monterey littoral faunas, the
older of which is found only along the more immediate coast
region of the present time. If we accept these as representing
real stages and not merely distributional facies, they strengthen
materially the idea suggested by stratigraphic considerations and
geographic distribution of depositional types, that the invasion
of the Monterey sea was a gradual process, that during the earlier
part of the period (zone of Turritella hoffmanni or inezana)
deposition was confined to the present coastal region, and that
only during a later stage did it stretch over across the present
coast range country and cover part of what is now the San
Joaquin valley and Sierra Nevada foothills. And while coarse
terrigenous deposits were gathering along the Cantua-Coalinga-
Kern River-San Emigdio border region (the Temblor beds of
F. M. Anderson, Vaqueros formation of Arnold, Robert Ander-
son, Johnson, ete.), very pure diatomaceous shales were forming
over most of the coastal Monterey-San Luis-Santa Barbara
region, and even over some of the interior—the McKittrick-

Temblor region—(Monterey shale or Monterey formation of

various authors).

93 Proce. Cal. Acad. Scei., 4th Ser., vol. 3, pp. 161-182 (1912).

94 Merriam recognizes an upper zone in the Contra Costa County region
(see page 206 of this paper), but it is not discussed here, as it is either
absent or at least has not yet been definitely recognized in the other
Monterey areas.

240 University of California Publications in Geology (VoL. 7

SUMMARY STATEMENT OF VARIOUS OTHER CONCLUSIONS

No natural formations or groups of sediments exist which
correspond to the littoral faunal stages recognized in the Mon-
terey series. Any system of nomenclature which gives both
faunal-temporal and formational significance to its terms (except
for the series as a whole) is fallaceous and pregnant of confusion
and misconceptions.

Faunal zones and stages should have faunal names, as
““Agasoma zone,’’ stage of 7. ocoyana, ete., and not formational
names (Vaqueros fauna, ete., as recently proposed by J. P.
Smith). Names primarily based on lithologie distinctions (depo-
sitional facies) have only very local significance as ‘‘ formations. ’’
The term ‘‘ Vaqueros sandstone’’ has only a facies value and not
a formational one even in the Salinas valley region, where it was
originally applhed; Temblor as applied in the Kern River region
seems quite surely equivalent to at least part of the ‘‘ Monterey
shale’’ on the west side of the valley. For economic purposes,
or purposes of local mapping, and of structural geology it is
often important to map local depositional facies—why not call
them such? In the Salinas valley region in studying the water
resources it may be important to separate the sands from the
shales. Why not call them ‘‘Sandstone facies,’’ ‘‘ bituminous
shale facies’’?

Similarly in the oil fields the distinction is important. In
the Santa Maria fields the petroleum bearing ‘‘ basal sandstones’’
would be more expressive to geologists and oil men alike than
‘Vaqueros formation.’’

Locality names are not objectionable—though not always nec-
essary—such as Modelo sandstone, Puente sandstone, Puente
shale,—to apply to locally developed depositional divisions—
provided they are presented in their true value.

Names like ‘‘ Temblor beds’’ (in the sense of a supposed lower
Miocene formation and faunal stage below the ‘‘ Miocene shale”’
formation and zone), Vaqueros formation or sandstone (mean-
ing the same), Monterey shale (in the sense of a supposed middle
Miocene formation and faunal stage above the Vaqueros), Modelo
formation (for the artificial group of Bull. 309, on the north side

1913] Louderback: The Monterey Series 241

of the Santa Clara Valley, or for the depositional facies south
of the valley), Puente formation (in the sense of a local repre-
sentative of the Monterey series) are either misleading or un-
necessary and should be dropped.

Whether all or part of the faunal stages of the Monterey
series be made equivalent to the Lower Miocene, the Oligocene
or divided between them, in the vicissitudes of the history of
long-distance faunal correlation, the series here studied repre-
sents a natural stratigraphie unit, with characteristic and related
faunal elements, and clearness and simplicity demand _ that
throughout this province of deposition it be designated by a single
provincial name. The term Monterey in the form Monterey
series has been established by priority and consistent usage and
its use is urged as the general designation for deposits of this
province and depositional evele.

Transmitted November 14, 1912.

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13. Spodumene from San Diego County, California, by Waldemar T. Schaller.

14. The Pliocene and Quaternary Canidae of the Great Valley of California, by

John... Merriam 2.209.026 3 re i ae ee oa

15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson...

16. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam

17. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew
Wie WSO a eo ce 2a ee 1 en

18. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. Evan

19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmo

20. Euceratherium, a New Ungulate from the Quaternary Caves of California, b

William J. Sinclair and H. L. Furlong._._.-.-----------22---2-2- ;

21. A New Marine Reptile from the Triassic of California, by John C. Merria

22. The River Terraces of the Orleans Basin, California, by Oscar H. Hershey...

VOLUME 4.
1. The Geology of the Upper Region of the Main Walker River, Nevada, by D
MD, GSraithe sce a ee eee

A Primitive Ichthyosaurian Limb from the Middle Triassic of Nevada, by Jo
CG. Merriam 26225 Se A a ae esas ee

Vow Ce Osmo rit Sees Bee NS Ae a ree ee
Areas of the California Neocene, by Vance C, Osmont
Contribution to the Palaeontology of the Martinez Group, by Charles HE.
New or Imperfectly Known Rodents and Ungulates from the John Day Ser

William J. Simelarir oe... esccecs eee cece cee cence cence pn ecenenee cena
New Mammalia from the Quarternary Cayes of California, by Wilham J.8
Preptoceras, a New Ungulate from the Samwel Cave, California, by Eustac

OCR egnCe UGH ADs DO)

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 11, pp. 243-256 Issued April 25, 1913

SUPPLEMENTARY NOTES ON
FOSSIL SHARKS

DAVID STARR JORDAN anp CARL HUGH BEAL

In the Bulletin of the Department of Geology, University of
California publications for 1907, the senior writer published a
memoir entitled ‘‘The Fossil Fishes of California.’’ In this
paper, with other matters, there is a record of the species of
sharks known from the Miocene deposits of Kern County,
California.

Stanford University has lately received from Mr. Charles
Morrice of Bakersfield another large collection of shark’s teeth.
These were obtained from a hill on the west side of Kern River,
about a mile distant from the stream and four miles from Oil
City. These were preserved in a fine hard silt. The collection
was made by Mr. Morrice at the suggestion or with the aid of
Mr. F. M. Anderson of the California Academy of Sciences,
Professor Harry A. Millis of Stanford University, Professor
W. C. Mitchell of the University of California, and Mr. A. C.
McLaughlin of Palo Alto.

Three other papers have dealt with the Miocene sharks of
California. Two of these, by Louis Agassiz, preceded the paper
of 1907. Professor Agassiz published in the American Journal
of Science and Arts, pp. 272-275, a paper entitled ‘‘Notice of
Fossil Fishes Found in California by W. P. Blake.’’ This
article with a few verbal changes and a page of engravings is
reprinted in the appendix to Lieutenant Williamson’s ‘‘ Report on

244 University of California Publications in Geology (Vou.7

Explorations in California,’’ (U.S. Pace. R. R. Surv. for 1853, pp.
313-316, pl. 1). Since 1907 a review of these papers of Agassiz
and of Jordan has been published by Maurice Leriche of Lille. It
is entitled ‘‘Observations sur les Squales Néogénes de la Cali-
fornie’’ and published in the Annales de la Societe Géologique du
Nord (tome xxxvii, p. 302, December, 1908). This paper is
based chiefly on the descriptions and figures published by the
senior author in 1907. It consists mainly of a comparison of
these California species with those of the same horizon in Europe.
Leriche regards most of the species as identical with the
European species. It may be freely admitted that in several
cases no differences can be made out from the teeth alone. In
several genera of sharks, the dentition is the same in all the
several species. But to unite nominal species from opposite
sides of the globe has also its difficulties. In most cases, the
existing species of shark are largely localized, and it must have
been so in the Miocene period. There are reasons of convenience
for having a different set of specific names in each distinct faunal
area. At the best, the substitution of Leriche’s names for those
of Agassiz in California is the exchange of one doubtful opinion
for another. If we trust to teeth alone certain species will
appear to have not only a cosmopolitan distribution but an
abnormally wide range in geologic time. As the wide-ranging
forms among the existing sharks have been studied more ecare-
fully, these have been split up into distinct species showing
more or less definite localized differences. While no one can be
sure that some of these sharks were not fully identical with
European forms, we know that some of them are not so. We
know also that the Miocene fauna of California is in general
wholly different from that of Europe and also from that of the
eastern portions of the United States. Where a California
species has received a distinctive name we may provisionally
allow that name to stand, even if no known characters separate
the teeth in question from those of their European analogies.
Still later, several authors (Ameghino, Leriche, Woodward,
Gaudry, Tournouer, Priem) have written on the Tertiary fishes
of Patagonia, in which region occur a series of sharks, the teeth
of which show a very strong resemblance to the species known

1913] Jordan—Beal: Supplementary Notes on Fossil Sharks 245

from California. Geographically these are nearer to California
than the fauna of Europe. Many shark teeth of similar types
also occur in the Tertiary of Kansas.

The new material examined in this paper is from the follow-
ing localities:

1. The collection above mentioned from the lower Miocene,
Temblor horizon, near Oil City, Kern County, California, the
work of Mr. Charles Morrice and others.

2. One specimen from the collections of the University of
California, taken from Chico (upper Cretaceous) sandstone.

3. A collection of fragments of broken teeth from the Eocene,
Oligocene, and Miocene of various localities on the coast of
Oregon has been presented by Mr. Harold Hannibal of Stanford
University.

GEOLOGIC RANGE OF WESTERN AMERICAN SHARKS

Cret- Pleisto-
Species Triassic aceous Eocene Miocene Pliocene cene Recent

Acrodus wempliae

Jordan, x =
Myliobatis merriami

Jordan and Beal, re a a 2 x
Carcharhinus antiquus

Agassiz, fe ae ors X
Carcharias clavatus

Agassiz, a Pe = x
Carcharias morricei

Jordan and Beal, - = Es x
Carcharodon arnoldi

Jordan, sd = - = ae x
Carcharodon megalodon

Charl. (branneri

Jordan) = a = x 2 ES -
Carcharodon rectus

Agassiz, = 3 4 x
Carecharodon riversi

Jordan, ae ks = x eS x
Dalatias occidentalis

Agassiz, = 2 = xs Px
Galeocerdo productus

Agassiz, rs a os X
Galeorhinus hannibali

Jordan and Beal, a 2s = x >
Hemipristis chiconis

Jordan, ob x Ee = 2 fe ;
Hemipristis hetero-

pleurus Agassiz, 8 Z Bs x

246 University of California Publications in Geology [Vou.7

GEOLOGICAL RANGE OF WESTERN AMERICAN SHARKS— (Continued)
Cret- Pleisto-
Speciés Triassic aceous Eocene Miocene Pliocene cene Recent
Heptranchias ander-
soni Jordan, - 2 = x

Hybodus shastensis
Wemple, xe

Isurus desori Agassiz, 23 xe

Isurus hastalis Agassiz
(I.smithii Jordan), .. S x x

Lamna appendiculata

Agassiz, zs x x
Rhinoptera smithii

Jordan and Beal, = ae x x
Squatina lerichei

Jordan and Beal, = a3 Bs x

The following is a list of the fossil sharks of California as
now recognized :

Family HYBODONTIDAE
Genus Hyspopus Agassiz

1. Hybodus shastensis Wemple.
Upper Triassic at Bear Cove, Shasta County.

Genus Acropus Agassiz
2. Acrodus wempliae Jordan.
Upper Triassic of Bear Cove and North Fork, Shasta
County.

Family HEXANCHIDAE
Genus HeprraNcuHias Rafinesque

3. Heptranchias anderson Jordan.
Miocene at Barker’s Ranch, Kern County.

This M. Leriche identifies with Notidanus primigenius Agassiz
of Europe. This may be correct, but the living species of
Heptranchias of California, H. maculatus Ayres, is distinct from
the European H. cinereus. (Notidanus is a later synonym of
Hexanchus. )

1913] Jordan—Beal: Supplementary Notes on Fossil Sharks 247

Family GALEORHINIDAE
Family GALEOCERDO Muller and Heule

4. Galeocerdo productus Agassiz.

Leriche identifies this with Galeocerdo aduncus Agassiz of the
Swiss Eocene. The four figures given by Jordan (‘‘ Fossil Fishes
of California’’) in figure 13, page 114, represent this species.
The smaller ones in figure 4 on page 102 referred doubtfully to
Galeocerdo represent something else. Leriche suggests possibly
a species of Aprionodon. Perhaps they are side teeth of Odon-
taspis; e, as well as a, in figure 4, belongs to Galeorhinus.

Genus GALEORHINUS Blainville
(Galeus Cuvier 1817, not of Rafinesque 1810)

Dd. Galeorhinus hannibali Jordan and Beal, new species.

Miocene of Barker’s Ranch; Pliocene of Temescal Canon.

The species indicated by Jordan (1907) under the name of
““Galeus (zyopterus Jordan and Gilbert?)’’ can hardly be
identical with the existing shark thus named.

The tooth from the Phocene of Temescal Canon, Santa
Monica Mountains, is described as similar to the teeth of
Galeorhinus zyopterus, but more nearly erect and less notched
on the outer margin than are most of the teeth of that species.
The tooth is small, narrowly triangular, turned moderately out-
ward, the base with five small cusps on the inner margin, the
cusp nearly entire. Tooth e, figure 4 (figs. a, a’, of the present
paper), from the Miocene of Kern County, must, as indicated by
Leriche, belong to this form. This tooth may be taken as type
of the species.

The species is named for Mr. Harold Hannibal of Stanford
University.

Under the ruling of the International Commission of
Zoological Nomenclature, the name Galeus cannot be used for
this genus, which becomes Galeorhinus.

248 University of California Publications in Geology [Vow.7

Genus HemIpristis Agassiz
(Dirrhizodon Klanzinger)

7. Hemipristis heteropleurus Agassiz.
Miocene, Ocoya Creek, Barker’s Ranch, Oil City.

As indicated by Jordan and by Leriche these teeth are iden-
tical with those of Hemipristis serra of the European Miocene.
The genus Hemipristis is no longer represented among the living
fishes of America or Europe.

8. Hemipristis chiconis Jordan.

Chico deposits (upper Cretaceous) near Martinez.

Genus CARCHARHINUS Blainville

(Carcharias Cuvier 1817, not of Carcharias Rafinesque
1810, which is Odontaspis Agassiz)

9. Carcharhinus antiquus (Agassiz).
Miocene of Ocoya Creek and Oil City.

We have no new material of this species.

The tooth indicated as No. 7 Carcharias sp. by Jordan, page
104 (fig. 5, upper figure) is perhaps a tooth of Carcharodon
rectus from near the angle of the jaw. A better specimen is in
the Morrice collection. We refer this with doubt to Carcharodon,
probably to C. rectus. ;

Under the rules of the International Commission of Zoological
Nomenclature the name Carcharias used originally for a single
species, which later became the type of Odontaspis, must replace
Odontaspis. The great genus of sharks called Carcharias by
Cuvier must take the name Carcharhinus. This is a most incon-
venient but apparently inevitable shifting of names.

1913] Jordan-Beal: Supplementary Notes on Fossil Sharks 249

Family CARCHARIIDAE
(Odontaspididae )
Genus CaRcHARIAS Rafinesque

(Odontaspis Agassiz, not Carcharias Cuvier)

10. Carcharias clavatus (Agassiz).
(Lamna clavata Agassiz: Jordan)
Ocoya Creek, Miocene of Kern County.

This is not evidently different from Odontaspis cuspidatus
(Lamna cuspidata Agassiz) of the Miocene and Oligocene of
Europe as Agassiz has indicated and as Leriche again points out.

The teeth of Zamna and of Carcharias are very similar.
Leriche observes (translated) ‘‘ As I shall show in a later memoir
(‘‘Poissons Oligocénes de la Belgique’’) this species was provided
with symphyseal teeth and should therefore be referred to the
genus Odontaspsis.’’

11. Carcharias morricet Jordan and Beal, new species.
(Text fig. c)

To the genus Carcharias we refer with some doubt, four well
preserved teeth differing in size and form but apparently belong-
ing to the same species. They are from the Miocene of Kern
County. They owe their dissimilarity probably to their being
from different parts of the mouth. Two of the teeth are bent
sharply back at the root and taper from an almost round cross-
section to the point. The root is very thick and broad and is
almost as wide as the tooth is high. On the sharply curved
margin of the tooth, a large basal denticle protrudes from the
root.

Another tooth, probably belonging to the same species, but
from a different part of the mouth, is about one-half again as
high as the preceding ones, the base is sub-triangular and does
not bear as great a relative width to the height of the tooth as
in the preceding case. The crown is rather convex in cross-sec-
tion, is notched anteriorly and bears two sharp, rather large
denticles on the posterior margin. This tooth may be taken as
the type of ‘the species which is named for Mr. Charles Morrice.

250 University of California Publications in Geology (Vou. 7

Family LAMNIDAE
Genus LamNna Cuvier

12. Lamna ornata Agassiz.
Navy Point, Benicia.

We know nothing of this species.

13. Lamna appendiculata Agassiz.

Two teeth, from hard Chico sandstone, are rather long and
flexuous. According to Dr. Jordan, ‘‘These belong to a species
of Lamna apparently related to the one figured by Mr. Stewart
as Lamna appendiculata, from the Cretaceous of Kansas.’’ It
is, however, doubtful whether this can be the same species, as
there was no geographical connection between the California
and Kansas seas during the Cretaceous time.

The large tooth is slender and tapering with sharp, knife-like
edges, the altitude measuring about twice the width at the base
of the root. The other standing next to it in the jaw is much
smaller but similar. This specimen has no basal denticles, which
are so characteristic of the larger tooth.

Mr. Harold Hannibal has collected from the Eocene Arago
formation of Cape Gregory, Oregon, a tooth of this same genus
but perhaps of a new species. It is a little higher compared
to the width than the preceding species, sharper and more
flexuous, and there are minute striations extending from near
the point of the crown to the root of the tooth. This tooth has

a basal denticle.

Genus Isurus Rafinesque
(Oxyrhina Agassiz)
14. Isurus hastalis (Agassiz).
(Oxyrhina plana Agassiz, loc. cit., p. 274. Oxyrhina tumula
Agassiz, loc. cit., p. 275. Isurus smithi Jordan, loc.
Cit. p. 111)
Miocene of Kern County, San Diego County, and Fresno
County.
Teeth of a giant species of Jsurus are excessively common in
Miocene deposits of Kern County, far outnumbering all other

1913] Jordan—Beal: Supplementary Notes on Fossil Sharks 251

shark’s teeth. There is no doubt that Leriche is quite right in
referring all of these to one species, plana being the upper
lateral teeth, twmula the lower, and smithii the long and flexuous
front teeth. Similar differences are shown in the dentition of
the existing species, Zsuwropsis glauca.

In this genus there are never serrations on the edge of the
teeth and never denticles at base.

Some of these teeth are two and one-half inches in height, this
indicating a shark of sixty feet more or less in length.

Leriche further identifies this species with Jswrus hastalis .
(Agassiz) of Europe, which view is very likely correct. Dr.
Priem refers similar teeth from the Miocene of Patagonia to
Tsurus hastalis and Woodward records the same species from
Argentina.

Another tooth referable to Zsurus hastalis was obtained from
the lower Miocene at Stanford University, near the base of the
intruding basalt columns. Another was found by Mr. Harold
Hannibal in the Arago formation (Eocene) near Cape Gregory,
Oregon. Still another was obtained by Mr. Hannibal from the
Miocene of the east shore of Coos Bay, Oregon. This is quite
typical of the lateral upper teeth of Zsurus hastalis.

A large vertebra, nearly two inches in diameter, probably
belonging to Zsurus hastalis was also found by Mr. Hannibal.

15. Isurus desori (Agassiz).
Chico formation, upper Cretaceous.
A single tooth, doubtfully identified with this species of the
European Cretaceous.

Genus CARCHARODON Smith

16. Carcharodon megalodon Charlesworth.
(Carcharodon branneri Jordan )

This giant shark’s tooth named Carharodon branneri is dis-
tinguished from the equally large Carcharodon megalodon of the
Miocene of regions about the Atlantic Ocean, by the smaller
number of serrations on the large teeth. Of these we count 80
to 100 on each side in the specimens from California called

252 University of California Publications in Geology [Vou.7

Carcharodon branneri, while in Carcharodon megalodon Charles-
worth from South Carolina we count 100 to 120. This distine-
tion is of very doubtful value, and most likely Leriche is right
in referring C. branneri to the synonym of Carcharodon megal-
odon, a species recorded from the Tertiary in various parts of
the world, and undoubtedly the largest of all sharks. A large
specimen of C. branneri in Mr. Morrice’s collection agrees fully
with C. megalodon from South Carolina.

17. Carchorodon rectus, Agassiz.
Miocene of Kern County.

This species, if different from Carcharodon megalodon is dis-
tinguished by the presence of a lateral denticle. It may be the
young of one of the other species mentioned here, although none
of these have a lateral denticle. The serrae are about fifty on
each side. Probably the upper figure on page 103 of Jordan’s
memoir represents a lateral tooth of this species. If so, it may
be known also by its very coarse serrae.

18. Carcharodon arnoldi Jordan.
Pliocene, Pescadero; Quaternary, Rustic Cafion, Santa
Monica. |
This species is identified by Leriche with the living species
Carcharodon carcharias (i), (Carcharodon rondeleti Muller
and Kurle). It has larger teeth than any yet found of the living
species, and these are more closely serrated. It is therefore

probably distinct.

19. Carcharodon riversi Jordan.
Santa Monica, Port Los Angeles, Quaternary; Miocene of
Kern and Fresno Counties.

Leriche refers this species also to the living Carcharodon
carcharias. This view seems improbable. It is perhaps not
distinct from C. arnoldi, and Carcharodon rectus may not be
different. In the living species, C. carcharias, the serrations on
the teeth do not exceed 35-on each side, those of the middle of
the side having most. C. riversi has about 40, C. arnoldi about
50, and C. rectus 50 to 60 on each side. C. rectus, as already

1913] Jordan—Beal: Supplementary Notes on Fossil Sharks 253

indicated, may be a lateral tooth and the others may represent
different parts of the jaw. Possibly the name Carcharodon
rectus should include arnoldi and riversi. But Leriche seems to
regard C. rectus as the young of C. megalodon (—=C. brannert).
Any view of the case is at present a guess, one doubtful opinion
being set off against another.

There are at least two fossil and one living species of
Carcharodon represented in the California fauna. These are
C. megalodon, C. arnoldi (ineluding C. riversi?) and C.

carcharias.

Family DALATIDAE

Genus Dauatias Rafinesque

(Scymnus Cuvier )

20. Dalatias occidentalis (Agassiz).
Miocene, Ocoya Creek, Oil City; Plocene, Temescal
Canon.

No new specimens of this species have been noted.

Family ECHINORHINIDAE
Genus Ecutnoruinus Blainville

21. Echinorhinus blaket Agassiz.

This species we have not seen.

Family SQUATINIDAE
Genus Squatina Duméril
22. Squatina lerichei Jordan and Beal, new species.
(Text fig. b)

This species was not named, but was noted and figured (p.
119, fig. 4d) by the senior author as perhaps belonging to the
genus Chiloscyllium. Dr. Leriche suggests correctly that the
tooth in question is that of a species of Squatina. Additional
material is in the collection of Mr. Morrice.

There are five very small teeth, narrow, triangular and nearly
erect, with the root very wide, its width nearly twice the height

254 University of California Publications in Geology [Vou.7

of the tooth, and projecting backward so that the tooth rests
on a triangular base double-notched posteriorly. The tooth will
stand when set erect on the table. The enamel of the crown
extends downward on the root in front to its base. All the
species of Squatina are essentially alike in dentition, but as they
are local in distribution the living Californian species (Squatina
californica), being confined to this Coast we may indicate the
California Miocene species by a separate distinction. It is named
for Maurice Leriche of Lille.

Family MYLIOBATIDAE
Genus RHINoPTERA Kuhl
(Zygobatis Agassiz)

23. Rhinoptera smithvi Jordan and Beal, new species.

(Text fig. e)

Under the name of ‘‘Zygobatis species’? Agassiz* records a
fragment of a tooth of this genus from Ocoya Creek. Several
similar fragments have been obtained at different times from the
Miocene of Kern County. The species seems to be abundant.
Only single teeth more or less broken have been found. Most
likely these belong to the genus Rhinoptera rather than to
Aétobatus (Myliobatis) to whieh Jordan doubtfully refers it
(loc. cit., p. 119). F. Priem (Bull. Soc. Geol. France, 1911, plate
IIT, fig. 77, figures a tooth almost precisely similar from the
Miocene of Argentina as ‘‘Rhinoptera sp.’’

The teeth from Barker’s Ranch and Oil City are laterally
much elongated, with serrated or comb-like edge. The breadth
of the tooth and the size of the serrations vary considerably, but
they must be of the same species. It is not possible to be certain
as to the genus to which these fragments belong, but they may
be recognized from the accompanying drawing.

Some imperfect, smaller specimens of this species were taken
from the Eocene of Big Creek, Oregon, by Harold Hannibal.

The species is named for Dr. James Perrin Smith, palae-
ontologist of Stanford University.

* Agassiz, Am. Jour. Sci. Arts, 1856, p. 275; U. S. Pac. R. R. Surv.,
p. 316, pl. 1, figs. 31-35.

1913] Jordan—Beal: Supplementary Notes on Fossil Sharks 255

Fig. a. Galeorhinus hannibali Jordan and Beal. Pliocene of Temescal
Cafion and Miocene of Kern County, California. :

Fig. b. Squatina lerichei Jordan and Beal. Miocene of Kern County,
California.

Fig. c. Carcharias morricei Jordan and Beal. Miocene of Kern County,
California.

Fig. d. Myliobatis merriami Jordan and Beal. Miocene of Kern
County, California.

Fig. e. Rhinoptera smithii Jordan and Beal. Miocene of Kern County,
California.

256 University of California Publications in Geology |Vou.7

Genus My .iospatis Cuvier

24. Myliobatis merriami Jordan and Beal, new species.
(Text fig. d)

In the collection of the University of California (no. 19714)
is a fine large specimen composed of the three median teeth of
a jaw of a species of this genus. These teeth are convex in
surface, and curved in outline, the surface marked by longi-
tudinal streaks of enamel which do not however roughen the
surface. The teeth are one and one-quarter inches in breadth,
each tooth five times as broad as long. The root surface is
smooth, without the comb-like structures seen in Rhinoptera.
The form of the edge of each tooth shows that it was flanked by
smaller teeth as in living species of Myliobatis. In Stoasodon
(Aetobatis of Miiller and Henle) there are no lateral teeth.

The type is from the Miocene near Oil City. It is named
for Dr. John C. Merriam, palaeontologist of the University of
California. A few other specimens have been since received from
Mr. Morrice.

As the generic name Myliobatis was first used about 1811 by
Geoffroy St. Hilaire, it must have priority over Aetobatus pro-
posed by Blainville in 1817.

As stated elsewhere (American Naturalist) the species de-
scribed in Jordan’s memoir (‘‘Fossil Fishes of California,’’ p.
131) as Merriamella doryssa proves to be a stickleback and
should stand as Gasterosteus doryssus. It was later described
by Dr. O. P. Hay, from the same Miocene deposits on the
Truckee River, as Gasterosteus, williamsoni leptosomus (Proce.
U.N; Mj xxanr, 190%. 27).

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. Two New Species of Fessil Turtles from Oregon, by O. P. Hay.
. A New Tortoise from the Auriferous Gravels of California, by TW. J. siete
Rigs. LO amd 11 in ome COVER. nen enencennnnnaneneneneteeecnensconnsentnnnrenamennecmnnamesnts

CONIA corny

=
S00

13. Sicdnnieht from San Diego County, Catone, - Waldemar T. Schaller...
14. The Pliocene and Quaternary Canidae of the Great Valley of California, by

John, ‘C."'Nienriam (55 tr > 2 a saves ea ens TO, epee ee
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C.
16. A Note on the Fauna of the Lower Midcene in California, by John C. Merriam...
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew

18. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. Eva
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmo
20. Euceratherium, a New Ungulate from the Quaternary Caves of California,

William J. Sinclair and E. L. Murlom grt. ..2:2. sete ote geneiea ss oe eee ee 2
21. A New Marine Reptile from the Triassie of California, by John 0. M
22. The River Terraces of the Orleans Basin, California, by Oscar ‘A. Horsitey, ate

VOLUME 4.

asc A SOS <I et alle ae 2 ER a gee ccs ant aides
A Primitive Ichthyosaurian Limb from the Hides, Triassic of Neva)

C. Merriam | Pi et

V. C. Osmont
Areas of the California Neocene, by Vance 6. Osmont...
Contribution to the Palaeontology of the Martinez Group,
New or Imperfectly Known Rodents and Upevetes from the John Day i

TVW aM tea rae) se SN A Yee ere ae }
. New Mammalia from the Quarternary Caves of Californ
. Preptoceras, a New Ungulate from the Samwel Ca Ca
Barong ------------nneeececeneeseteeeseeetecescnee iotpstecscececpions

ea Sok we po

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 12, pp. 257-298, pls. 11-14 Issued April 29, 1913

FAUNA OF THE EOCENE AT MARYSVILLE
BUTTES, CALIFORNIA

BY
ROY E. DICKERSON

CONTENTS
PAGE
BBiTaraitaysc CU Gita Og eee ost see gO cS eee econ ee naz ees ck sbbesdyhsaeseo oe eiee se 258
TBR Laie Ch eg Disk rea eke Ww 5 oe rrr 258

Stratigraphic Relations and Lithology of Marysville Buttes Eocene.... 261
List of the Fauna from the Uppermost Hocene of Marysville Buttes... 262

Bathymetric Relations of the Fauna ................--.e:seeeceeeeeeee sees 265
Climatic Conditions during Accumulation of Marysville Buttes Eocene... 267
Geoonam bya ote phone) OM SCAN ce scccesccceces: coq cee ceaee seeds cere este e ace cvecsaecesteres==ne ess 268
Zonal Position of the Marysville Buttes Fauna ..............-.--.---------------- 270
Bhvewilen one Mast Ot SOUth DB UbbC tase scsenc ec te nn encee ace e eee cence renee cn seeree cen aeeceeseeeeee 273
FS SEEN A ee Re ee a 274
IDESCTIPtLON® OLsSPCCLOS) <...b.-c22--cee--ceccce=! scsccsccteceeetecevaseceseseseseccuceccececeesuesceeeceis~st 274
SMC CHO GUS AS [0 sy eecee ceca see seeeecocenceeec=cceocsunpasvescecdaescseecceectecezetssscnici-sietesssticlis 274
Murnissmonolitera (COON)! st. cssssesscccecns cece ccere adie st ccn edn gensseeweecceecseee 275
HAs erste a (ep topo oan Tek] 0 ee eae Io ree emer -11 (9)
MumrismoumbuTalis: (COO PCL, eee 2cccccet sec cesses scoteateoeccseecseenteses22eccezzcssn2-2escsecesesses 276
Turris inconstans (Cooper) ...........--.---.----- Babee dco aoe nees coe loctenscesceeittesscast 276
PDT ES app ety Kan STA meu (C.0 0) Gly) ee ceeeeterec esnere=scenessces ne ceees cra meneseneecen coe =ececeaecees 277
1 Dyiertl Dey, willl neceny eesti ey OLY 0) wpe eee ee eee er err eS EE 277
SS UUTC ll alemel eas Ket gr 1) eee oe 2 neem See we ce csceee econ sees oe cevecte. cee severreet tees aes e soa.
Sureula crenatospira Cooper ...........-..-.-- poe rege rete cuescepee ee See cent custctees; a Ssteee 278
SECU al Mo liad, WS Py ecsecescs2ceecs se cesecenecenoncace=cesee=en re ee 279
Suuncullaid diva St amlay (0 OPN) csececscas ste secsecesec-seeesseeecesesege--cecestcsosuensee2oe-tse 2
Wondienalsomercalllumlam© 0 O70 CM eres steencescsscsstsccefeeee=sutseedessveccseevicseeseeencztceceeasece :
Fusinus (Priscofusus) lineatus, n.sp. ........
Terebra wattsiana Cooper ...............-.---------
Cancellaria stantoni, n.sp. ...........-
Cancellaria irelaniana Cooper .......
Siphonalia sutterensis, n.sp. ...........
NIRS ASIS TS) ha “cers nese Sen Ae EERE Se 283

(CUM) SMU, pa WUE a SUES Oy, an Ee er ee eS 283

258 University of California Publications in Geology [Vou.7

Voluta lawsoni, 1.8): .t:-ssese sac en ee 284
Turritella ‘merriami,, WsSP. -..2:-c..sc-ssce--cce-c-csece ness see ts ee ar ss eee eee 284
Olivula marysvillensis, W:SP. -222ccc¢-c.-c0c20-csceece seas techeseetessov eee ee 286
Ancilla (Oliverato) californica Cooper .........--.-2----::::sceecseceeeeeseeeeeeeeeeee 286
ArehitectOnica Weaverl, D.SP. -..---fccce-ccceecececceceeee cec-- pee sate eee eee 287
Caricella Stormsiamay mS p..c.ccc-tecce cece oe een ree 287

Phos(?) martini, ms. 222-2...
CalliiostomiaC?)) armolda,: iS ce-ceeecc2cccceeeeeeseccese es tese eee eee

Bittium longissimum Cooper

Cain dium’ (dalllii) m-Sps se2ccctececeeccceecoceee-e-eeteeeee ee
Glycimeris marysvillensis, n.sp

Nucula. Cooper, iSpy 222. -2cccecceeccceederceccerceceeecenectcee= soeese a2 c25c=keenes inet eee
Mellimarsutterensiss WES yp spc eecsceee ce coe esearch eee 290
Mrochocyathus (?)) PONE WS. ececscceeeceeeee see ten ae ee ne anes es seen 291

INTRODUCTION

The Eocene fauna obtained from outcrops at Marysville
Buttes, California, has been known from the work of W. L.
Watts and J. G. Cooper of the California State Mining Bureau,
and Waldemar Lindgren and H. W. Turner of the U. S. Geo-
logical Survey.

In the course of a study of the Eocene fauna of California,
small collections, the gifts of O. W. Jasper and W. L. Watts,
representing the Eocene fauna from Marysville Buttes attracted
the writer’s attention by their wonderful preservation, and by
the peculiar faunal phase represented. Most of the species in
these collections had not been recognized in other Eocene loeali-
ties. In order to determine the zonal relations of this fauna,
the writer visited the Marysville Buttes in December, 1911, to
collect for the Department of Palaeontology of the University
of California. The writer is particularly indebted for many
valuable suggestions to Professor J. C. Merriam, under whose
supervision this work was undertaken.

REVIEW OF LITERATURE

The Eocene of Marysville Buttes was first described by W. L.
Watts! who referred to it using the name ‘‘Cretaceous B,’’ in
the sense in which it had been used by Gabb.?

1 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.

2Gabb, W. M., Geological Survey of California, Palaeontology, vol. J,
preface, p. 19, 1864.

1913] Dickerson: Fauna of Eocene at Marysville Buttes 259

In this note Watts referred to the sedimentary beds and recog-
nized their geographic relation to the central igneous rocks. ‘‘In
ascending the most southerly peak from the Moody ranch patches
of light colored sand toward the base of the mountain mark the
sedimentary formation and the coal measures. A few fragments
of fossiliferous rock, showing Cretaceous fossils may be found on
a portion of the slope. The best exposure of sedimentary rocks
was seen at the base of the West Butte about a mile from the
village of that name.’’ He recognized an unconformity between
the white sandy formation, dip about 15° 8.W. and the under-
lying ‘‘Cretaceous’’ shales and clayey sandstone, dip 70° 8.W.
A partial list of fossils identified by Cooper was given. Most
of these were recognized as occurring in ‘‘Cretaceous B’’ of
Gabb. Through the courtesy of State Mineralogist Storms, the
writer examined this collection and redetermined some of the
species. The species which were redetermined are given in
parenthesis after Cooper’s determinations.

Leda gabbi Conrad Ostrea idriaensis Gabb
Lunatia hornii Gabb Corbula parilis var(?) Gabb
Olivella mathewsonii Gabb Mysia polita Gabb
Nucula solitaria Gabb Modiola eylindrica Gabb
(Nucula cvoperi, n.sp.) (Modiola eylindrica Gabb is prob-
Nassa cretacea Gabb ably an incorrect determina-
Turritella uvasana Gabb tion.)
Turritella merriami, n.sp.) Cardita planicosta Lam.
Turritella chicoensis Gabb Area hornii Gabb
(Turritella merriami, n.sp.) Cardium translucidum Gabb
Meretrix hornii Gabb (Cardium dalli, n.sp.)
Galerus excentricus Gabb Dentalium, sp.
Cardita veneriformis Gabb (prob- Morio tuberculatus Gabb
ably the young of Cardita Architectonica hornii Gabb
planicosta) (Architectonica weaveri, n.sp.)

Cueullaea, sp.

Dr. J. G. Cooper* deseribed the new species collected by
Watts on the west side of West Butte, discussed the conditions
of deposition and suggested that the strata were Eocene, al-
though he used ‘‘Cretaceous B’’ as a synonym in some of the
descriptions of new species. All of these descriptions are given
at end of this paper and most of the species are refigured. Cooper
wrote at a time when the debate concerning the age of the

3 Cooper, J. G., Catalogue of California Fossils, Bull. No. 4, Cali-
fornia State Mining Bureau, Sept., 1894, pp. 36-45.

260 University of California Publications in Geology [Vou.7

so-called ‘‘Cretaceous B’’ beds of Gabb was still undecided and
on this account many points in his discussion are somewhat con-
fused.

Lindgren and Turner* in the Marysville Folio described the
relations of the sedimentary beds to the central igneous core,
divided the sedimentary beds into two formations, the Ione and
the Tejon, recognized the age of the Tejon as Eocene, and the
Ione as Miocene. This description is as follows:

‘‘Between the exterior mud-flows and the massive core, and
strongly contrasting with them, there often occur a series of
smooth, rounded hills forming a frequently interrupted ring
a mile or less in width. These hills are not voleanie but consist
of a series of sandstones (usually soft), white or dark clays and
eravelly beds. The beds are very much disturbed and dip at
all angles and in all directions. As a rule, however, they dip
away from the central core, and when near it stand at high
angles, sometimes vertical. At the immediate contact with the
massive voleanic rocks these sediments are usually hardened. No
voleanie detritus of the same rocks of which the Buttes are
made up is found in them, and it may be regarded as certain that
they were laid down before the period of voleanie activity. The
oldest of the formations belongs to the Tejon formation (Hocene) ;
it has thus far been identified only in the sedimentary area
northeast of the village of West Butte. It is here composed of
ereenish sandstone and shales, adjoining the voleanic masses
and dipping at high angles east or west. A thickness of several
hundred feet of sediments is exposed. Some of the beds contain
abundant marine fossils, characteristic of the Tejon among which
a small coral (Trochosmilia striata Gabb) is most abundant.
Cardita planicosta, a form eminently characteristic of the Tejon
is also found. Overlying these beds are light-colored, soft sand-
stones and clays, dipping west at an angle of about 20°, which
have been referred to the Ione formation. The other sedimentary
areas consist largely, if not entirely, of these soft light-colored
beds.’’ Lindgren® in a recent publication summarizes the dis-

4 Lindgren, W., and Turner, H. W., Marysville Folio, U. 8. Geol. Surv.
Folio 17, April, 1895.

5 Lindgren, W., The Tertiary Gravels of the Sierra Nevada of Cali-
fornia, Professional Paper, U. S. Geol. Surv., No. 73, pp. 23-25; 1911.

1913] Dickerson: Fauna of Eocene at Marysville Buttes 261

cussion of the Ione and Tejon given in the Marysville Folio, and
in addition gives a list of marine fossils found two miles east
of South Buttes.

STRATIGRAPHIC RELATIONS AND LITHOLOGY OF MARYSVILLE BUTTES

EOcENE

According to the authors of the Marysville Folio, the buttes
consist of a central core of coarse grained andesite which was
foreed up in the valley floor, a ring of sedimentary beds which
were upturned when the lava was foreed out, and a ring of
andesitie muds which were thrown out from secondary craters
on the edge of the sedimentary ring. 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 the South Buttes. 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 deposited on the
Eocene as an alluvial fan. The Ione in turn is overlain by
andesitie mud flows—now firmly cemented—which dip to the
west about 4°—5°.

An east-west section through West Butte largely adapted
from the Marysville Folio shows the following sequence on the
west side:

100 feet of green-gray sandstone and shale with limestone con-
eretions marking the upper limit of the Kocene.

300 feet of green-gray, glauconitie 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.

[ Vou. 7

262 University of California Publications in Geology

Ei
eae? ( Al i t
LSS
4 ; Zr

EY,

BS x7
PRINS OS

Hii.
Ny

4
PSUS VANS POV

Figs. 1 and 2. Map of Marysville Buttes region with section showing sequence of
geologic formations. Al, alluvium; Nat, andesitic tuffs; Ni, Ione; Tj, Tejon; Na, andesite;
Nr, rhyolite. Seale, 1% inch=1 mile. Fig. 1, areal relations of formations; fig. 2, east-
west section along line AB as shown on fig. 1.

Ze 20°)

Alluviurm findesilig tufls Tone Eocene Andesite Rhyolilé
ond breccias

1913] Dickerson: Fauna of Eocene at Marysville Buttes 263

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 con-
eretions, which are sometimes yellow, contain many small, dark
ereen to black, rounded grains. When these are carefully ex-
amined with a hand lens they are found to be foraminiferal casts
composed of glauconite. The green shales as well as the sand-
stone 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
ereen glauconitic sandstone and shale are absolutely indicative
of the Martinez in the middle California region. Glauconitic
sandstone also oceurs in the Tejon of the Mt. Diablo region.

On the east side of South Butte the writer has mapped an-
other Eocene 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.

List oF THE FAUNA FROM THE UPPERMOST EOCENE OF
MaryYSsvILLeE Burres

The writer found most of the following species at the locality
to which reference was made by Watts, and by Lindgren and
Turner. The species starred (*) were reported by Cooper, but
‘were not found by the writer. The single species marked by a
dagger (+) was found at a locality two miles east of South Butte.

The occurrence of each species is marked by an ‘‘x’’ in the

columns representing separate localities.

6 Watts, W. L., The Gas and Petroleum Yielding Formations of the
Central Valley of California. Bull. No. 3, California State Mining Bureau,
p. 9, Aug., 1894.

7 Lindgren, W. and Turner, H. W., Marysville Folio, U. 8. Geol. Surv.
Folio 17, p. 2, April, 1895.

264

Aneilla (Oliverato) californica Cooper ......

Astyris, sp.

Architectonica weaverl, n.Sp. --...-.--t.:-202.

*Bittium longissimum Cooper
*Cancellaria irelaniana Cooper
Canecellaria stantoni, n.sp. -

Caricella stormsiana, 1isp. 222022.22ee sees

Cordiera gracillima Cooper

Clavellleretalbnll ater aS 0 cece ene eee

Cylichna costata Gabb

Calliostoma(?) arnoldi, n.sp. ..............---.

Drillia ullreyana Cooper

bentalium stramineum Gabb ......................--

fusinus (Priscofusus) lineatus, n.sp. -.........

Ficopsis remondii Gabb
Galerus excentricus Gabb
Lunatia hornii Gabb
Lunatia nuciformis Gabb
Morio tubereulatus Gabb
Niso polito Gabb

Olivas marys villenisis; ess. cesses steeeeae ess

Olivella mathewsonii Gabb
Perissolax blakei Gabb

DEA aKoFsh CC i)), aoskeh tis hol kei sha) 0) peaerer en reeece as eee er

Surcula crenatospira Cooper ..

PSU ADUESY, Sao ly es Ryley OWN SY OV ee see ee ee er

Sureula clarki, n.sp.
Sureula davisiana (Cooper)

Sureula (Sureulites) sinuata Gabb —..........

Siphonalia sutterensis, n.sp. ..-....------------------

Tritonium californicum Gabb
Tritonium whitneyi, Gabb
~Lerebra wattsiana Cooper .

AWibrenay ie Ey voal(ei alent, Wakls30y) cere eee ene

Murs han CenS Oma gms y) yyeeees-eeereeeseeeeeennne aces

Turris perkinsiana (Cooper)
Turris inconstans (Cooper)
Turris monolifera (Cooper)
Turris suturalis (Cooper)

Wola, TawSOmis WSs) cece eeceee eae steneceeeeee

Acila, ef. truncata Gabb
Area, ef. hornii Gabb ...
Avicula pellucida Gabb

Camda alla pie Spy eesce ees cesesee recente

Corbula parilis Gabb
Corbula hornii Gabb
Cardita planicosta Lamarck

Mt.
Marysville Diablo
Buttes

MoO

i <i i

A wR

Ce << |

ei i i |

mK KM WK HK

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4

ial

<< << |

University of California Publications in Geology

Near

[ Vou. 7

Region Fort Tejon Other localities

ie i <i a)

4
‘

ial

”“

ial

x Oregon

x Coalinga

x Coalinga
x San Diego

x Oregon

1913] Dickerson: Fauna of Eocene at Marysville Buttes 265

Mt.
Marysville Diablo Near
Buttes Region Fort Tejon Other localities
Dosinia elevata Gabb -........222..-.-2-.0.-220000-----+ Exe x x es

Glyeimeris cor Gabb ...........222...2:.:22:002eeeeeeees x x
Glycimeris marysvillensis, n.sp. .-............-.--- xe E : a
Me Clay Cally tor Coma Cie saree ee eee n ee ceeecereeeeteneens x x x
BaVibysticzagn Olli al Grav 22.22.cscco sca ccsstee-esceeeeeseeeeeseanee x cx x
IMiere brixG 2) Sps> ‘acs cssctsec2ctec-cnecs0> sesc-2eececucases xe
*Meretrix hornii Gabb ...............2..2..-2-:20--0---+ x xe 3 es
INAUC WAN COOPETI, NSs cee ce seececsceceeasteseecuseane aK a
Ostrea idriaensis Gabb .......-,-.2--...2-0..0--- x x x New Idria,
Coalinga
Solen parallelus Gabb ~............2----------.--.------ oe x x
Mamessconradiama Gaby) 22222 .cescceccecesece sees caee x x x
iuvellima,sutteremsis, m.Sp. 2222.22: x > x
- Schizaster lecontei Merriam .... x x x
Trochocyathus striatus Gabb x x
Trochocyathus(?) perrini, n.sp. -.......2.-22----- ae
Cancer, Sp. ........--- x =
INIOVGUGYSEEIIE 25) 0 eae ar ete ee seer eee x é : x Coalinga
FS )y/ARGXOR YoY 6 UUs) oe tear ese ee Neen x

BATHYMETRIC RELATIONS OF THE FAUNA

Dr. Cooper® in discussing two collections of fossils made by
Watts from the San Joaquin Coal Mine near Coalinga, Fresno
County, and Marysville Buttes incidentally states his ideas con-
cerning the bathymetric conditions under which this fauna was
deposited as follows: ‘‘It is certain at least that the two localities
from which Mr. W. L. Watts obtained the specimens described,
furnished no Ammonitidae but this may be explained on the
theory that they represent shallow water deposits close to a
seashore or estuary, in which large quantities of vegetable mat-
ter from the land were accumulated. Both the probable habits
of the species found at the coal mines near Huron, Fresno
County (as compared with nearly related species), and the pres-
ence of coal in the rocks containing them, point to such a con-
clusion, and the occurrence of many of the same species, to-
eether with a thin bed of coal somewhat further away, indicate
that the species from Marysville Buttes inhabited a similar but
somewhat deeper sea.”’

8 Cooper, J. G., Catalogue of California Fossils, Bull. No. 4, California
State Mining Bureau, p. 36. 1594.

266 University of California Publications in Geology [Vou.7

Cooper, in placing the species referred to Potamides(?)
davisiana under this genus, which is confined to brackish water
or estuarine conditions, also leads one to infer that these strata
are estuarine deposits. One of the specimens shows that his gen-
eric classification, due to a superficial resemblance to Potamides
diadema Gabb is incorrect. The form referred to Potamides is
a Surcula. The formation of glauconite by deposition in the
tests of foraminifers, the occurrence of the genus Trochocyathus,
and of certain genera of Gastropoda and Peleeypoda indicate
that these beds are not in-shore deposits.

Thompson and Murray® in discussing the bathymetric distri-
bution of glauconite state that—‘‘it appears to be most abundant
about the lower limits of wave tidal and current action or in
other words in the neighborhood of what we have termed the
mud line surrounding continental shores. In the shallower depths
beyond this line, that is to say, in depths of about 200 and 300
fathoms, the typical glauconitiec grains are more abundant than
in deeper water, but glauconitic casts may be met with in de-
posits in depths of over 2,000 fathoms. No typical glauconitie
sands have, so far as we know, been recorded in process of forma-
tion in the littoral or sub-littoral zones.’’

Mosley’? gives the range of Trochocyathus found at present
in the sea as from 100 fathoms to 750 fathoms.

Vaughan" in his monograph on corals considers them as pecu-
liarly valuable indicators of bathymetric conditions of deposition.

Tryon” gives the following ranges for some of the genera
of Gastropoda and Peleeypoda listed above. ‘‘The Cancellariae
from low water to forty fathoms,’’ Turris, low water to 100
fathoms; Corbula, lower laminarian zone to 80 fathoms; Dosinia,
low water to 80 fathoms ; Cardium, from sea shore to 140 fathoms ;
Nucula, 10-180 fathoms; Leda, 10 to 180 fathoms; Twrritella,
approximate range near 100 fathoms; Tapes, low water to 100
fathoms. The relatively small number of species of the genera

9 Challenger Report, Deep Sea Deposits, p. 378-391. 1891.

10 Challenger Report, Zoology, vol. ii, pt. vil, p. 1382. 1881.

11 Vaughan, T. W., U. 8. Geological Survey, Monograph 43, The Eocene
and Oligocene Corals of the United States, p. 23-33. 1900.

12 Tryon, G. W., Structural and Systematic Conchology, vol. 1, 1882;
vol. 2, 1883; vol. 3, 1884.

1913] Dickerson: Fauna of Eocene at Marysville Buttes 267

which range from low water to 100 fathoms was decidedly
noticeable when the collection lsted above was made. The
lamellibranchs were, except Nucula, Leda and Cardiwm, very
rare.

The evidence taken as a whole leads to the conclusion that
the glauconitie sandstones and shales were laid down in water
about 100 fathoms deep.

CLIMATIC CoNnbITIONS DuRING ACCUMULATION OF MARYSVILLE
Burtres EocENE

Another factor which must be considered in connection with
this unique fauna is the climate at the time of the deposition of
the sediment containing it. Dr. Cooper*® in describing Turris
monolifera makes the following note: ‘‘The occurrence of seven
new pleurotomidae without many other univalve shells, and
especially the absence of many forms of genera allied to Fusus
described by Gabb, is a condition of distribution indicating prob-
ably that a warmer sea existed where they are found than at most

localities of similar age in California.’? Thorough collection does
not sustain his view entirely. The number of Pleurotomidae is
noteworthy, but they are associated with twenty-eight other
univalve shells and seventeen lamellibranchs. Several of these
gastropods are allied to Fusus. He was comparing a fauna which
is not essentially littoral to species which are found in a por-
tion of the Chico, the Martinez, and the Tejon. The writer is
in thorough agreement with this suggestion of a warmer climate
during the deposition of the Eocene of the Marysville Buttes, but
the littoral or shallow water fauna of the typical Tejon also sug-
gests a warmer climate than that of the present day. Several
of the species, Voluta lawsoni, Tapes conradiana, Oliverata cali-
fornica, Surcula crenatospira and Cardium dalli, still retain high
coloring suggesting strongly the tropical forms of today. Sev-
eral of these genera are according to Tryon confined to or char-
acteristic of tropical and sub-tropical waters. Among these are
Voluta, Siphonalia, Turris, Surcula, Drillia, Terebra and Can-
cellaria.

13 Cooper, Dr. J. G., California State Mining Bureau, Bull. No. 4, Cata-
logue of California Fossils, pp. 89-40. 1894.

268 University of California Publications in Geology [Vou.7

It is not probable that the peculiarities of this fauna are due
to climate, as the fauna of the type Tejon is also tropical or sub-
tropical. The great variety of genera, and the great abundance
of forms at most localities of the Tejon indicate life conditions
such as are generally found in tropical or subtropical seas.

The widespread geographic distribution of certain species char-
acteristic of the Tejon is especially noteworthy. Cardita plani-
costa is nearly world-wide, Meretrix hornii, Tapes conradiana,
Dentalium stramineum, Perissolar blakei, and many others
range from Washington to San Diego at least. C. E. Weaver’s
collections from the Eocene of Washington, the California Acad-
emy of Sciences’ collection made by Martin in Oregon, and the
Tejon collections show a great number of species common to all
three localities and the writer infers from this that unusually
uniform conditions of climate prevailed along the coast.

When the fauna from the Eocene of Eastern Oregon listed in
the description of Turritella merriami, n.sp. (p. 287), is compared
with that of the typical Tejon the difference is seen to be very
slight. But few new species are found there, although the
locality is several hundred miles distant. A Tejon fauna from
San Diego collected by Mr. Wm. Kew does not show a great
number of species different from those of Mt. Diablo region.
Several species which were first known only from San Diego
have since been recognized in the Tejon of the Mt. Diablo region.
Geographic separation is thus seen to be insufficient to account
for the great difference between the Tejon of Fort Tejon and the

Marysville Buttes Eocene.

GEOGRAPHY OF THE TEJON SEA

Extensive Eocene deposits occur along the coast of Oregon
and Washington as well as a considerable distance inland. Eocene
deposits are found in Southern Oregon but no Eocene has been
reported from the Klamath Mountains. That most of the Eocene
of Oregon and Washington is Tejon can not be questioned if a
careful study of the fauna is made. Form after form is seen
to be identical beyond a doubt with those of the Tejon, although,
as one might expect, there are many species which are new. Com-

D>
wo

1913] Dickerson: Fauna of Eocene at Marysville Buttes 2

ing down the coast, the next Eocene is reported by Gabb™ from
Round Valley, Mendocino County. This is Tejon.

Tejon is reported from Lake County, which is west of the
Marysville, although none is reported from along the coast of
Sonoma or Marin Counties or the San Francisco Peninsula.
The Tejon Sea probably once extended over the present site of
Lake County, and reached nearly continuously through Napa
County along the west side of the San Joaquin Valley to its
southern end. Extensive lava flows in Napa county prevent a
tracing of Tejon sediments to the Mt. Diablo region. Tejon is
reported on the eastern side of the San Joaquin along the Merced
River. The authors of the Santa Cruz foliot® do not report any
Tejon, although the Butano formation may be of this age.

Fairbanks in the San Luis folio states that during Eocene
times that region was a land area. Extensive Eocene deposits
are found, however, in Santa Barbara County immediately to the
south and at various other places along the coast to San Diego,
and Lower California as far south as 29° 30’, N. latitude.

In the discussion of bathymetric relations it was pointed out
that the probable depth of the Eocene sea during the time of
deposition of the green shales at Marysville Buttes was approxi-
mately 100 fathoms. As this is considerably deeper than the
fauna of most Tejon localities indicates as prevailing during the
deposition of their enclosing sediments, we may conclude that
in the northern portion of the state some deposits were formed
along the coast of an open ocean. This idea is also reénforeed by
the statements of Thompson and Murray?’ in discussing the geo-
graphic distribution of glauconite. They conclude that ‘‘ Where
the detrital matters from rivers are exceedingly abundant, and
where there is apparently a rapid accumulation, glauconite,
though present, is relatively rare; on the other hand, along high
and bold coasts where no rivers enter the sea, and where aceumu-
lation is apparently less rapid, glauconite appears in its typical
form and greatest abundancee.”’

14Gabb, W. M., California Geological Survey, Palaeontology, vol. 2

(preface, p. 13), 1869.

15 Branner, J. C., Newsom, J. F., and Arnold, R., U. 8S. G. S., Folio 163,
p. 3, 1909.

16 Challenger Report, Deep Sea Deposits (p. 382), 1891.

270 University of California Publications in Geology [Vou.7

That these glauconitic sediments were deposited along an open
ocean seems probable. Whether this is a unique condition
in the Tejon is a question that arises immediately. The condi-
tions of deposition during portions of Tejon time were evidently
fairly uniform over California. White to dull red quartzose
sandstones with cavernous weathering are typical of Tejon sec-
tions from San Diego to Lake County. Such a uniformity in
lithology might be explained by deposition along a coast un-
broken by large islands and peninsulas. The evidence indicates
that no extensive or continuous land masses existed along the
California coast west of the Sierras during Tejon time.
Although sediments deposited in fresh or brackish waters are
found, they appear to represent local oscillations of the strand
line or estuarine deposits only. During most of Tejon time, a
great embayment probably stretched from southern California
to the region of Marysville Buttes, curving westward north of
Mendocino County.

ZONAL POSITION OF THE MARYSVILLE ButrTres FAUNA

Of the species listed above from the Eocene at Marysville
3uttes the following oceur both in the Martinez and the Tejon:

Cylichna costata Perissolax blakei
Dentalium stramineum Acila truncata
Galerus excentricus Leda gabbi
Lunatia hornii Schizaster lecontei
Niso polito

There are no distinctive Martinez species in the list, and the
fauna has little or no suggestion of Martinez affinities. The
following species are reported from Tejon localities:

Cancellaria irelaniana Cardita planicosta

Lunatia nuciformiis Dosinia elevata

Morio tuberculatus Glycimeris cor

Olivella mathewsoni Meretrix hornii

Sureula (Sureulites) sinuata Mysia polita

Sureula monolifera Ostraea idriaensis

Tritonium ealifornicum ' Solen parallelus ‘
Tritonium whitneyi Tapes conradiana

Area hornii Trochocyathus striatus
Avicula pellucida Nodosaria, sp.

Corbula_ parilis

~l
ey

1913] Dickerson: Fauna of Eocene at Marysville Buttes 2

In the total list of sixty-five species a total of only thirty-one
are reported from other Tejon localities. Nearly all of these
forms, as the table shows, have a wide geographic range. The
partial list of species culiected by Bruce Martin from the Umpqua
formation, given under the description of Turritella merriami,
(p. 287), shows that many of them are found in the Eocene of
Oregon. Many of these forms have also a great stratigraphic
range. The exact range of some of these species is not known.
Cardium cooperi is probably the progenitor of Cardium dalli.
Trochocyathus striatus occurs in the San Francisco Bay region
above the coal strata north of Mt. Diablo and in uppermost
Tejon, south of Mt. Diablo where it is associated with Cardiwm
coopert. This suggests that the uppermost Eocene of the Marys-
ville Buttes is younger than that of Mt. Diablo Region. Without
doubt the beds at Marysville Buttes are Eocene but their fauna
apparently represents a faunal zone which has not been reecog-
nized elsewhere. This faunal assemblage has over thirty species,
which have not been found at other localities.

It has been shown that the peculiar aspect of the Marysville
Buttes fauna is not due solely to local facies of climate, or of
habitat along an open ocean. Life in relatively deep water no
doubt influenced its development, but this factor does not explain
the great difference between this fauna and that found in the
uppermost Tejon of the Mt. Diablo region. As nearly as ean
be determined, the peculiarities of the Marysville Buttes fauna
are due in some measure to its having lived in a division of
Eocene time from which no adequate representation of the
marine life of the Pacific Coast has been known up to the
present time. Evidence that the Marysville Buttes collections
represent a zone slightly different from the uppermost Tejon of
the Mt. Diablo region is found in the fact that his assemblage
differs much more from the Martinez fauna than does the fauna
of any portion of the typical Tejon. This would indicate
that the Marysville Buttes zone is removed from the Mar-
tinez by a longer period than is the typical Tejon. That the
Marysville Buttes fauna is later than the Martinez and chiefly
later than the typical Tejon is shown (1), by the absence of such
genera as Cucullaea, Anchura, Heteroterma, Urosyca, and TTer-

PH Ps University of California Publications in Geology [Vou.7

coglossa; (2), by the presence of such genera as Bittium, Cor-
diera, Cancellaria, and Drillia; (3), by the occurrence of such
species as Trochocyathus striatus, Tritonium californicum Cor-
bula parilis, Glycimeris cor, Tapes conradiana, Oliverato cali-
formca, and Cardium dalli, n. sp.

Of the first mentioned genera Cucullaea and Anchura are
characteristic of the Cretaceous and of the earliest Eocene on
this coast. Heteroterma and Urosyca are wholly restricted to
the Martinez. Since none of these genera are represented in the
Marysville Buttes Eocene, the fauna is evidently not pre-
Martinez. Bittium, Cordicra, Cancellaria, and Drillia are all
represented in stages ranging from the late Eocene to the Re-
cent. Since they occur in the Eocene strata of the Marysville
Buttes, it is evident that this fauna is a phase of the later Eocene
or Tejon, as they are certainly more characteristic of the later
Eocene than they could be of any horizon inferior to the early
Eocene of the Martinez stage. The species mentioned above all
occur in the uppermost Tejon of the Mt. Diablo region except the
last, whose precursor, C. cooperi, 1s found there. Trochocyathus
striatus is restricted to the upper portion of the Tejon of this
locality. Cardium dalli, n.sp., seems to the writer to have
evolved from C. cooperi and hence to have lived at a later time.
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 and not to depth of water, climate,
or other causes. That it evolved from the typical Tejon there
ean be little doubt. We are led to the conclusion that the
Marysville Buttes fauna is not only further removed from the
Martinez than is the typical Tejon, but that the distance remov-
ing it from the Martinez is measured toward the Recent fauna.
In other words the evidence indicates that the Marysville Buttes
fauna represents a later zone or stage of the Eocene than the
typical Tejon.

1913] Dickerson: Fauna of Eocene at Marysville Buttes 273

Tue TeEJoN East or Soutu Burrs

Two fossiliferous localities in the Ione formation are de-
scribed in the Marysville folio, and these places were recently
mentioned by Lindgren" in the Tertiary Gravels of the Sierra
Nevada of California as follows:

‘*Marine fossils were found about two miles east of South
Butte and two and one-half miles north-northwest of South
Butte. The fossils, while not abundant, point to a Miocene age.
These beds are believed to be the exact equivalent of the Ione
formation exposed along the foothills of the Sierra Nevada.
Their aggregate thickness is very considerable, 1,000 feet being
a fair minimum estimate. The following fossils were identified
by Messrs. Stearns and Dall:’’

Crassatella collina Conrad Macoma, sp.

Venericardia borealis Conrad Tapes (Cuneus), sp.
Verticardia (?), sp. Saxidomus, sp.

Acila castrensis Hinds Cardium modestum Conrad
Liocardium apicinum Carpenter Galerus, sp.

Fusus (Exilia), sp.

In another place Lindgren states: ‘‘These fossils are regarded
by Messrs. Stearns and Dall as Miocene.’’

The writer visited these localities recently and found the fol-
lowing fauna at the first locality, two miles east of South Butte:

UNIVERSITY OF CALIFORNIA LocALity 1856

Ancilla (Oliverata) californica Yritonium whitneyi Gabb
Cooper Tritonium, ef. californicum Gabb

Galerus excentricus Gabb Cordiera gracillima Cooper
Voluta lawsoni, n.sp. Lunatia nuciformis Gabb
Dentalium stramineum Gabb Cardita planicosta Lam.
Trochocyathus striatus (Gabb) Cardium dalli, n.sp.

Turris monolifera (Cooper) Tellina sutterensis, n.sp.

Turris suturalis (Cooper) Meretrix, cf. ovalis Gabb

The fossils were found in limestone fragments which are ex-
actly like those in the Eocene on the west side of the mountain.
Essentially the same stratigraphic sequence is found on the east
side as is seen on the west. The same bright red clay and glau-

17 Lindgren, W., The Tertiary Gravels of the Sierra Nevada of Cali-
fornia, Professional Paper 73, U. 8. Geol. Surv., pp. 57, and 120, 1911.

274 University of California Publications in Geology [Vou.7

conitic shales and limestones occur here. There seems no room
for doubt that these beds represent the same horizon in the Tejon
as those on the west side of the Buttes.

The writer did not find fossils in the locality two and one-half
miles north-northwest of South Butte, but the same bright red
soil with coneretionary limestone occurs here as a narrow strip
bordered on the east and west by Ione conglomerates. It is
lithologieally the same as the Tejon area two miles south. Since
these are the only loealities which were described as furnishing
marine Ione. fossils it would seem that marine Tejon has been
confused with Ione, and that there is no evidence to indicate the
presence of an extension of the sea into this region in Miocene
time.

SUMMARY

1. The Eocene of the Marysville Buttes is evidently of a
relatively late stage.

2. Glauconitie beds, previously known only from the Mar-
tinez in the California Eocene, are present in the uppermost
Eocene of the Marysville Buttes region.

3. There is no evidence of brackish water or of estuarine con-
ditions in the region of Marysville Buttes while the uppermost
elauconitic beds containing Tejon fossils were accumulating.

4. The fossil-bearing beds of the Marysville Buttes Eocene
accumulated in water about 100 fathoms deep.

5. The faunal zone represented by these beds appears to be
younger than the Tejon of the type localities.

6. The climatie conditions obtaining in the Marysville Buttes
region during the deposition of the Eocene beds were tropical
or subtropical.

7. The supposed marine Tone of Marysville Buttes is evi-

dently Eocene.

DESCRIPTION OF SPECIES
SYNECHODUS, sp.,
Plate 14, figure 7
Tooth with sharply tapering cusps. Median cusp nearly
straight, acute, margins sharp, inner side convex, the outer side
is nearly flat with a slight concavity near the root. There are

1913] Dickerson: Fauna of Eocene at Marysville Buttes 275

two much smaller cusps on either side of the median one. They
are both convex on the inner and outer sides.

University of California Loeality 1853.

Dimensions: Greatest length of middle cusp, 9mm; greatest
transverse diameter of base, 11mm.

TURRIS MONOLIFERA (Cooper)
Plate 11, figure 1

Surcula monolifera Cooper.—Cooper, J. G., Catalogue of California
Fossils, Bull. 4, Cal. State Mining Bureau, p. 39, 1894.

‘“‘Fusiform; nuclear whorls three, smooth, conical; the next crossed
by twelve or more strong, oblique riblets, which change on fourth or
fifth into a row of beaded knobs, forming an angle along middle of
whorls, increasing to thirty-five on ninth or body-whorl. Above this angle
are nine or ten fine revolving riblets, and three or four below it, the two
posterior being longest, and imperfectly beaded at the suture. On the
anterior whorls the medial knobs are sometimes doubled, and on the body-
whorl the revolving riblets are alternately large and small. Canal straight,
equaling the sub-oval mouth in length. Sinus deep, situated at the angle.
Length, 0.60 inch; breadth, 0.08; mouth and eanal, 0.34 long.

Five specimens obtained, agreeing well in characters, at Marysville
Buttes, by Mr. Watts. This is quite near to Gabb’s ‘‘Turris claytonensis,’’
from near the Mt. Diablo coal mines, but a comparison with his description
shows marked differences. Figures three times the natural size.

The occurrence of seven new Pleurotomidae without many other univalve
shells, and especially the absence of the many forms of genera allied to
Fusus described by Gabb, is a condition of distribution indicating prob-
ably that a warmer sea existed where they are found, than at most localities
of similar age in California.’’

Abundant at University of California Localities 1853 and

1856.
Dimensions: Length, 9mm; width of body whorl, 4mm.

TURRIS ANDERSONI, n.sp.
Plate 11, figure 2

Shell fusiform with rather short spire and a long body-whorl.
Whorls, about seven (two upper whorls missing), rounded, nodose.
The whorls are marked by eight rounded vertical nodes which
extend from a well marked suture over the entire whorl. The
lines of growth indicate a moderately deep sinus at the angle.
Mouth, oval, narrowing abruptly at a point about two-fifths of
the distance below the suture into a long narrow canal. Inner
lip, smooth.

276 University of California Publications in Geology [Vou.7

University of California Locality 1853. Named in honor of
Mr. F. M. Anderson, Curator, Department of Palaeontology,
California Academy of Sciences.

Dimensions: Length, 10.5mm; width of body whorl, 4.5mm.

TURRIS SUTURALIS (Cooper)
Plate 11, figures 6a, 6b

Mangilia suturalis Cooper.—Cooper, J. G., Catalogue of California Fos-
sils, Bull. 4, Cal. State Mining Bureau, p. 41, 1894.

“*Form lanceolate; nuclear whorls three, fourth with ten strong vertical
riblets, continuing on next five whorls, but decreasing to six on body whorl;
crossing entire whorl, but higher at middle, forming an obtuse angle, marked
by a strong revolving riblet; one strong riblet parallel to this close to the
suture, and one below angle. On the body they increase to over twenty of
uniform size. Strong lines of growth cross these throughout, showing a
deep sinus, mostly posterior to the angle. Canal slightly twisted. Length,
0.08; mouth 0.29 long, 0.06 wide. Two specimens found at Marysville
Buttes by Mr. Watts.’’

The canal of this species is entirely too long for a Mangilia.
The mouth is longer than the spire. The nodes on the body-whorl
do not decrease to six. Most of the whorls have eight or nine
instead of ten, and the body-whorl is no exception.

Dimensions: Height, 40mm; width of Body-whorl, 13mm.

TURRIS INCONSTANS (Cooper)
Plate 11, figure 5

Surcula inconstans Cooper.—Cooper, J. G., Catalogue of California Fos-
sils, Bull. 4, California State Mining Bureau, p. 40. 1894.

“*Shell long, fusiform, whorls about ten, the first two turbinate,
smooth; third to sixth with ten or twelve transverse close-set ribs, which,
on the other four whorls, show only on the posterior half of each, being
replaced by eight or ten revolving riblets, forming a cancellated sculp-
ture near middle, and toward the canal appearing alone. Mouth narrow,
sinus at angle, canal long. Dimensions, length, 1.10 inch; breadth, 0.25

inch, mouth, 0.50 inch.’’

The figure is triple the natural size.
Rare at University of California Locality 1853.
Dimensions: Length, 12mm; width of body-whorl, 4mm.

1)
-l
~l

1913] Dickerson: Fauna of Eocene at Marysville Buttes

TURRIS PERKINSIANA (Cooper)
Plate 11, figures 7a and 7b

Pleurotoma perkinsiana Cooper.—Cooper, J. G., Catalogue of California
Fossils, California State Mining Bureau, p. 40. 1894.

““Very long and slender; whorls about ten, rounded, the first two
turbinate, smooth; third with ten or twelve close-set vertical riblets,
crossed by eight or ten revolving ones, the vertical gradually increasing
to twenty-six on the body-whorl, forming a close beaded seulpture as
far as the middle of body-whorl, while the revolving ribs continue alone
on the body to canal. Varies also in relative strength of the two series
of riblets, at different portions of spire. Sinus close to suture, canal
straight, columella simple. Length, 0.60 inch; breadth, 0.15; mouth, about
0.25 long, 0.09 wide. This and the preceding (Twurris inconstans) have
many characters alike, and are both variable in similar directions, so
that at first they seemed varieties of one species, but the position of the
sinus and differences in size and form distinguish them. Two specimens
were found at Marysville Buttes by Mr. Watts.’’

This species was found at University of California localities
1853 and 1856. It is easily distinguished from Twrris incon-
stans by the absence of nodes and by the rounded form of its
whorls. Its sinus is not near the suture as Cooper states, but
near the middle of each whorl. It resembles Pusus diaboli Gabb
in general form but is slightly more slender, its longitudinal ribs
are curved, and not straight like those of F#. diaboli and its
whorls are rounder.

Dimensions: Length 22mm; width of body-whorl, 5mm.

DRILLIA ULLREYANA Cooper
Plate 11, figure 8

Drilla ullreyana.—Cooper, J. G., Catalogue of California Fossils, Bull.
4, California State Mining Bureau, p. 41. 1894.

““General form oblong-rhombie; first three whorls smooth, conical;
fourth with seven strong knobs crossing it, and continuing on the six
following at regular intervals; crossed by about ten fine revolving rib-
lets above the middle, and four stronger ones below, increasing to about
thirty of uniform size on the body-whorl and canal. Mouth nearly half
of whole length, acute posteriorly, with a slight angle on upper third.
Canal tapering, straight, sinus deep behind angle. Length, about 0.66
inch; breadth, 0.30; mouth and canal, 0.35 long, 0.12 wide. Marysville
Buttes, Mr. Watts; four similar specimens.

The canal is long for a Drillia, but not more so than in D. raricostata
Gabb, which this much resembles, differing in having the knobs more
numerous, shorter, and broader.’’

278 University of California Publications in Geology [Vou.7

Several specimens were found at University of California
Loeality 1853.
Dimensions: Length, 16mm; width of body-whorl, 6.5mm.

SURCULA CLARKI, n.sp.
Plate 11, figure 3

Shell, fusiform with eight (?) whorls, the body-whorl being
almost as long as spire. The whorls are marked by eight elongated
rounded nodes crossed by revolving lines. Four or five revolving
lines occur between the suture and the angle of the whorl. The
angle of the whorl is marked by a strong revolving rib. Another
strong rib oecurs just below the angle and two weaker ribs are
found on the space below. A moderately deep sinus is indicated
by the lines of growth above the angle. Mouth, elongate, oval;
canal, short.

University of California Locality 1853. Named in honor of
Bruce L. Clark, Instructor in Palaeontology, University of
California.

This species resembles Pleurotoma guibersoni Arnold, but it
has more nodes on its whorls, the revolving lines are different and
the nes of growth indicate without a doubt a sinus above the
angle.

Dimensions: Length, 10mm; width, 4.5mm.

SURCULA CRENATOSPIRA Cooper
Plate 11, figure 4

Surcula crenatospira.—Cooper, J. G., Catalogue of California Fossils,
Bull. 4, California State Mining Bureau, p. 39. 1894.

‘*Nuclear whorls three, smooth, large, the apical, immersed; other
spiral whorls five, turreted, gradually enlarging, each with about nine
rounded tubercles horizontally flattened, forming a chain around the
middle, and connected by two strong revolving ribs, making a sharp
angle. Above this are five or six fainter ribs, crossed by strong sinu-
ated lines of growth, and below a similar sculpture, the whole surface
being thus divided by strong reticulations, extending forward on body-
whorl about half its length. Mouth simple, sinus moderate, above angle,
canal long, straight, aperture as long as spire. Length, about 1.75 inch;
breadth, 0.80; mouth and canal, 1 inch long, 0.40 wide.

Not very near any of Gabb’s species of the family, except in the long
canal, which seems to have been more common in the fossil than in living
Pleurotomidae. The character of the sinus and sculpture ally this and

bo
I

1913] Dickerson: Fauna of Eocene at Marysville Buttes 9

some of the following to the sub-genus Clathurella, though according to
those who classify by the soft parts, such divisions are of little value.
They must be taken for all they are worth in fossil species, as necessary
divisions, in the absence of better ones.

Quite common at Marysville Buttes, where Mr. Watts and Mr. Ullrey
obtained 35 specimens. A very similar species inhabits the West Coast
of Mexico at present (S. olivacea Sby.)’’

Dimensions: Length, 37mm; width of body-whorl, 12m.

SURCULA HOLWAYIT, n.sp.
Plate 11, figure 9

Fusiform, with high spire; whorls number about eight (the
three (?) upper whorls are missing). The fourth, fifth, sixth,
seventh, and eighth whorls are marked by about twelve oblique
nodes which extend from the angle to the suture below but do not
appear on the space above the angle. These nodes are crossed by
two prominent revolving lines. The whorls are angular with
vertex of the angle about two-fifths of the distance above a
sharply impressed suture. The space above the angle is marked
by minute revolving lines and by sinuous lines indicating a deep
sinus above the angle.

Only one specimen was found at University of California
Locality 1853. Named in honor of Professor R. 8. Holway,
University of California.

Dimensions: Length of broken specimen, 18mm.

SURCULA DAVISIANA (Cooper)
Plate 12, figures 6a and 6b

Potamides davisiana Cooper.—Cooper, J. G., Catalogue of California
Fossils, Bull. 4, California State Mining Bureau, p. 44. 1894.

‘«FWirst three whorls convex, turbinate, smooth; the next six turreted,
increasing rapidly by wide, flattened expansions of the upper surface
of whorls, with a sharp raised carina half-way between the sutures,
from which the surfaces above and below diverge at a right angle.
Fourth whorl ornamented with about forty fine sharp riblets, strongly
curved to the left, above the carina, and giving it a serrate edge, then
passing down to the next suture. On the sixth whorl they are crossed
by two revolving riblets below the carina, and on the seventh or body-
whorl these increase to fifteen or more, with many intermediate smaller
ones, which finally entirely efface the vertical lines. Mouth triangular,
simple, inner edge of outer lip crenately notched, thin; (columella and
canal lost). Length, 1.16 inch (or more); breadth, 0.70; mouth, 0.50

280 University of California Publications in Geology |Vou.7

long, about 0.35 wide. The backward curve of the growth lines above
the carina suggests a Pleurotomoid shell, which is partly confirmed by
the curve forward of the posterior margin of outer lip remaining, but
the general form is so similar to that of Gabb’s Potamides diadema,
that I have placed it in that genus until better known. (See Pal. of
Cal., 1, p. 130, pl. 20). Resembles Pleurotoma (Perrona) spirata Lamk.
Marysville Buttes, one specimen from Cret. B, Mr. Watts.’’

Dimensions: Length of smaller specimen figured 10mm;
width of body-whorl 4mm.

Cooper’s type specimen is much larger than the small one
figured, but it does not show the canal or inner lip. The canal
is long and straight and the inner lip is smooth. The body-whorl
is marked by three prominent carinae in addition to the finer
revolving lines.

In the type, an older specimen, the space between the first
and second ecarinae on the body-whorl is sharply notched inward,
the vertex of the notch being central. The smaller specimens
vary much in the strength of the vertical ribbing. The small
specimen figured was found at University of California Loeality
1853.

CORDIERA GRACILLIMA Cooper
Plate 12, figure 3

Cordiera gracillima.—Cooper, J. G., Catalogue of California Fossils,
Bull. 4, California State Mining Bureau, p. 41. 1894.

‘Very slender, fusiform; first two whorls smooth, turbinate; third
with about twelve oblique subvertical riblets, which decrease to seven
on sixth whorl, narrow, meeting at sutures, and with four revolving
riblets crossing them, one along suture. A wide interval between this
and the next anterior, forms an obtuse angle on whorls, continuing to
the upper third of body-whorl, below which the vertical ribs disappear.
On body-whorl about eight revolving riblets cross these, with three or
four fine ones between each, and twelve to fifteen others below angle
pass around the canal. (The shells being imbedded in rock the exact
number of vertical ribs cannot be distinctly seen, whether seven or
eight, and the outer lip is too much broken to see the form of the sinus,
but it must be very shallow.) Mouth very narrow, sharp above, widest
at angle of lip, below curving to the left, gradually forming the canal.
Columella with four plaits at middle, the upper one, strongest. Length,
0.48 inch; breadth, 0.09; mouth, 0.14 long, 0.03 wide; canal, 0.10 long.

The figure is twice the natural size of the one specimen found at
Marysville Buttes by Mr. Watts. This is a decidedly different shell
from the two species figured and described by Mr. Gabb, both of which
were also found in Santa Ana Mountains, Orange County, by Dr. Bowers,
but in a very poor condition.’’

1913] Dickerson: Fauna of Eocene at Marysville Buttes 281

Cooper described this species from a single specimen im-
bedded in rock and hence a portion of the specimen was not
visible. The ‘‘wide interval’’ between the revolving rib near the
suture and the rib at angle is marked on the body whorl by five
riblets which alternate in size, and two or three on the penulti-
mate whorl. A persistent minor riblet can be seen between the
other revolving ribs. On the body-whorl 12 or 13 revolving ribs
alternating with minor riblets are found. The vertical ribs on
the body-whorl extend nearly the length of this whorl excepting
on the columella where they extend only a third to a half of the
length. The columella is marked by six plaits which increase
regularly in strength, the uppermost being the strongest. Colum-
ella slightly inerusted. Four or five nearly perfect specimens
were found at University of California Locality 1853.

Dimensions: Length, 10mm; width of body-whorl, 3mm.

FUSINUS (PRISCOFUSUS) LINEATUS, n.sp.
Plate 11, figure 12

Shell, small, spindle shaped, eight whorls. The first three
minute, rounded, smooth; the remaining whorls rounded and
marked by equal, flattened ribs with interspaces half as wide as
the ribs. The number of the ribs on fourth whorl is four, five
on fifth and sixth and about fifteen on the body-whorl. The
body-whorl is somewhat longer than the spire. Mouth, long,
slightly widened posteriorly and narrowed anteriorly into a short
eanal. Inner lip slightly inerusted.

University of California Locality 1853.

Dimensions: Length 6mm; width of body-whorl, 2mm.

TEREBRA WATTSIANA Cooper
Plate 11, figure 10

Terebra wattsiana Cooper.—Cooper, J. G., Catalogue of California
Fossils, Bull. 4, California State Mining Bureau, p. 39. 1894.

‘‘Whorls regularly tapering, about fourteen (upper three or four lost);
flattened, slightly turreted by narrowing in front, the highest with about
twenty-three narrow, close-set riblets crossing their whole width ver-
tically, and increasing to about fifty on body-whorl. Base and columella
smooth, mouth normal, canal much twisted, not deep. Length, about
1.75 inch; breadth, 0.45; mouth, 0.4; width, 0.10. More robust, larger,
and fewer-whorled than T. californica Gabb, also of Div. B, but nearly
allied to that species. A single specimen only was found at Marysville
Buttes by Mr. W. L. Watts.’’

282 University of California Publications in Geology [Vou.7

CANCELLARIA STANTONI, n.sp.

Plate 12, figures 2a and 2b

Shell, small, with five whorls, the first two, turbinate, smooth ;
the third whorl is cancellated by ten or twelve ribs. About
every fourth rib is enlarged. These heavy ribs are well rounded
on the fourth and fifth whorls and are more oblique than those
on the third. They extend from an indistinct, irregular suture
over the entire whorl. Strong revolving ribs with finer riblets
also decorate this beautiful little shell. Mouth, sub-oval; outer
lip thickened, rounded, and crenulated on interior. Columella
marked by three strong plaits, the posterior one being the
strongest. Canal short and very shghtly notched.

Three specimens were found at University of California Local-
ity 1853. Another specimen was found in the University of
California Collection from near Fort Tejon.

Named for Dr. T. W. Stanton, Chief Palaeontologist, United
States Geological Survey. °

Dimensions: Length, 12mm; width of body-whorl, 6mm.

CANCELLARIA ITRELANTANA Cooper
Plate’ 12, figure 8

Cancellaria irelaniana.—Cooper, J. G., Catalogue of California Fossils,
Bull. 4, California State Mining Bureau, p. 42. 1894.

‘*«Shell oblong fusiform; spire of eight whorls, the first three nuclear,
smooth, conical; fourth with nime prominent vertical ribs abruptly trun-
cate at sutures, and continuing thus on next three whorls, but on eighth
whorl becoming conical tubercles at posterior margins, more distinct
on body-whorl, the ribs disappearing. The three anterior whorls show
strong vertical lines of growth, or irregular sculpture, which above the
tubercles is crossed by three or four revolving raised lines. (Outer lip
broken off for about half an inch.) Columella with four very strong
and three fainter oblique folds (or ribs). Length, about 1.75 ineh;
breadth, 0.75; mouth, 0.87; width, (?).

““Only one specimen found at Marysville Buttes by Mr. Watts. This
shell is nearer to the sub-genus Narona than to any of the allied forms,
and in its spire much resembles the species living on our coast, C. (N.)
cooperi Gabb. Though Mr. Gabb described a Tertiary species as C.
vetusta, thus suggesting its absence from the Cretaceous strata, we
have here a proof of its presence in the Eocene or Cret. B. strata.’’

Arnold reports this form from the Eocene of the Coalinga
District.
Dimensions: Length, 43mm; width of body-whorl, 20 mm.

1913] Dickerson: Fauna of Eocene at Marysville Buttes 283

SIPHONALIA SUTTERENSIS, n.sp.
Plate 12, figure 1

Fusiform; whorls, nine or nine and a half. The first three
nuclear whorls are smooth while the rest are marked by ten or
eleven sharply pointed nodes. On the fourth to the ninth whorl
these nodes are crossed below the angle by three revolving ribs,
the one at the obtuse angle of whorl being the strongest. Two
or three riblets occur between the ribs. The portion of the whorl
above the shoulder is marked by riblets which alternate in size
and vary in number from eight or ten on upper whorls to fifteen
to twenty on the body-whorl. This portion is concave and on the
body whorl is channeled as well. The coneavity and channeling
are variable in amount. The canal is decidedly bent laterally.
Inner lp smooth and bent; outer lip crenulated on interior;
umbilicus small, ovate.

University of California Locality 1853. Named for its oc-
currence in Sutter County, California.

Dimensions: Length, 24mm; width of body-whorl, 11mm.

ASTYRIS, sp.
Plate 12, figure 4

Shell spindle-shaped with eight whorls. The first two whorls
turbinate, smooth. The third, fourth, fifth, sixth, and seventh
whorls smooth or marked with microscopic revolving lines; flat
sided ; the body-whorl rounded and marked by fine revolving rib-
lets. Outer lip broken, inner lip smooth. Canal, long for this
genus.

University of California Locality 1853. Only two small
specimens were found.

Dimensions: Length, 7mm; width of body-whorl, 3mm.

CLAVELLA TABULATA, n.sp.
Plate 12, figure 7

Shell robust, fusiform with at least nine whorls. The whorls
are flattened parallel with the axis of the shell, tabulate above
a very marked shoulder, a few rather fine revolving lines occur
on some of the whorls just beneath the angle. Suture impressed.

284 University of California Publications in Geology {Vou.7

The body-whorl with canal is nearly one and a half times as
long as the spire. It is suddenly contracted into, a long, narrow
canal about two-fifths of the distance below the angle.

Only one large specimen was found at University of Califor-
nia Loeality 1853.

Dimensions: Length, 73 mm; width of body-whorl, 28 mm.

VOLUTA LAWSONT, n.sp.

Plate 12, figures 5a, 5b, and 5e

Shell conical with short spire; eight whorls, the first and
second smooth and turbinate; the third, fourth and fifth decor-
ated by about ten vertical ribs, which end at the angle of the
whorl in spiny nodes. The angle of the whorls is nearly 90°.
The space above the shoulder is flattened and on the body-whorl
is channeled. Suture, linear, distinct. Outer lip, straight and
simple. Columella faintly incrusted. Inner lip marked by three
faint plaits. The body-whorl is decorated by fine revolving lnes
which increase in size on the lower part of the whorl.

Named in honor of Professor A. C. Lawson, University of
California.

The type specimen was found at University of California
Loeality 1853. Three other specimens were found at Locality
1856.

Dimensions: Length, 21mm; width of body-whorl, 10mm.

TURRITELLA MERRIAMI, n.sp.
Plate 13, figures 6a, 6b, and 6c

Shell moderate in size, elongate; whorls number about fifteen
or sixteen; the first four whorls are rounded and marked by three
strong revolving ribs with a single riblet between each pair. The
fifth, sixth, seventh and eighth whorls are also convex, but the
center of the convexity is below the middle of the whorl; these
whorls are marked by five nearly equal revolving ribs, equally
spaced. The rest of the whorls are markedly different from the
upper eight whorls. The first revolving rib below the suture
is much larger than the rest, and the space between it and the
impressed suture is flattened horizontally making a tabulate
shoulder. The next three ribs are equal and equally spaced. The

bo
On

1913] Dickerson: Fauna of Eocene at Marysville Buttes 8
fifth rib is stronger than the three above and a persistent riblet
is found between it and the fourth rib; the space between it and
the suture is twice as great as the space between the ribs above.
The lower whorls are flattened between the first rib and the
suture.

University of California Localities 1853 and 1855. Named in
honor of Professor J. C. Merriam, University of California.

The upper whorls resemble 7’. wvasana somewhat in apical
angle and ribbing, but their shape is slightly different. The
lower whorls bear a superficial resemblance to T. chicoensis in
that the suture is impressed and is bordered by a rim on the
whorl below and sometimes by one above. The rib below the
suture is much more developed in 7. merriami than T. chicoensis.
The number of ribs in 7. chicoensis is only three with four or
five minute revolving lines between, while there is only the one
mentioned above between the fourth and fifth rib in 7. merriami.

This species also occurs in the Eocene of Oregon.

Mr. Bruce Martin collected the following ‘‘under bridge at
mouth of Little River, North Fork of Umpqua River, 18 miles
northeast of Roseburg, Umpqua Formation,’’ California Academy
of Sciences Locality :

Oliverato californica Cooper Rimella canalifera Gabb
Cylichna costata Gabb Cerithium carbonicola Cooper
Morio tubereculatus Gabb Tapes conradiana Gabb
Loxetrema turrita Gabb Glycimeris ef. sagittata Gabb
Fusus mathewsonii Gabb Cardita planicosta Lamarck
Turritella uvasana Conrad Cardium breweri Gabb
Amauropsis alveata Conrad Crassatellites grandis Gabb
Turritella merriami, n.sp. Modiolus ornatus (Gabb)
Pseudoliva volutaeformis Gabb Corbula parilis Gabb
Phos(?) martini, n.sp. Lucina eumulata Gabb

Turritella merriami is in a collection made by Mr. Vance
Osmont at the Tesla coal mines.

Dimensions: Length of broken specimen (see figure 6b, plate
13), 30mm.

286 University of California Publications in Geology [Vou.7

OLIVULA MARYSVILLENSIS, n.sp
Plate 13, figures la and 1b

Whorls number six, the body-whorl being four times as long
as the spire. The body-whorl is decorated by distinct, close
longitudinal and revolving striae, and four prominent slightly
oblique revolving ribs on the lowermost third; spire covered by
a longitudinally striate deposit, angulated at suture of body-
whorl forming a raised band just below the suture. Aperture,
channeled posteriorly. Posterior portion of inner lip covered by
a callus which extends to top of spire. The lower portion of
the columella is marked by five small but prominent very oblique
plaits. Outer lip, thin and straight.

Only one small specimen was found at University of Califor-
nia Locality 1853. The only noteworthy difference between this
species and Olivula staminea Conrad of the Alabama Claiborne
is that the revolving ribs on the body-whorl are less oblique than
those of O. staminea.

Dimensions: Length, 10mm; width of body whorl, 4mm.

OLIVERATO CALIFORNICA Cooper
Plate 13, figures 4a and 4b

Oliverato californica.—Cooper, J. G., Catalogue of California Fossils,
Bull. 4, California State Mining Bureau, p. 43. 1894.

‘““About half of spire (the nuclear whorls) invisible in adult; mouth
with lips nearly parallel at middle; narrower at ends in the young, with
about ten faint ridges along columella, not passing inside; no umbilicus.
Dorsal surface marked by ridges from irregular thickness of the callus,
and a deep oblique furrow running from the anterior notch toward the
left, as in Pseudoliva, ete. Parallel to this, about six light ridges, remain
permanent behind it, thickened but not obscured by callus. General
form becoming more ovate with age, but always narrower in front.
Length, about 1.50 inch; breadth, about 0.85; mouth, 1.12 inch long, 0.50
wide. Eight specimens examined.

‘<Pour of the specimens are polished and colored a fine “saan, just
as in the living Erato vitellina. This color is confined to a thin outer
layer of the callus, as shown in the dorsal figures.’’

Dimensions: Length, 38mm; width of body-whorl, 23mm.

This form oceurs at nearly all the Eocene localities in the
Marysville Buttes. It is also found on the Umpqua River in
Oregon and at University of California Locality 195, ‘‘Concord

1913] Dickerson: Fauna of Eocene at Marysville Buttes 287

sheet 244 miles N.W. of Grayson Creek on main road from Mar-
tinez to Walnut Creek, north side of road.’’ It is associated with
Conus hornn, Turritella wvasana, Rimella canalifera, Cylichna
costata, Dentalium cooperi, Cardium breweri, Modiola ornata,
Meretrix horni, Cardita, sp., Tapes conradiana, and Trochocy-
athus striatus (?). Cooper figures a ‘‘young’’ form of Oliverato
which proves to be a new species, Caricella stormsiana.

ARCHITECTONICA WEAVERI, n.sp.
Plate 13, figures 2a and 2b

Whorls five or six, low, conical. The last two whorls are
decidedly concave and are marked by two nodose earinae, one
immediately above a sharp linear suture and the other just below.
The nodes on the upper carina are much closer together than
those on the lower. The upper nodes have a beaded appearance
while the lower nodes are distinctly elongated and extend nearly
to a revolving line in the middle of the smooth coneave portion
of the whorl.

A single specimen was found at University of California
Loeality 1853.

This form is readily distinguished from A. cognata and A.
hornit by its coneave whorls and distinctive decoration. Named
in honor of Professor C. E. Weaver, University of Washington.

Dimensions: Height, 7mm; radius, 10mm.

CARICELLA STORMSIANA, n.sp.
Plate 13, figures 3a and 3b

Shell pyriform, thin, smooth, spire low; whorls number six.
The first three nuclear whorls smooth and more convex than the
fourth and fifth whorls. Body-whorl twice as long as spire;
upper part swollen and smooth while lower part is marked by
eight or nine revolving transverse riblets. Outer lip, simple.
Canal short and shghtly twisted. At least two strong plaits
appear on the lower part of the columella.

Cooper described this as a young form of Ancilla (Oliverato)
californica, but the plaits on the columella throw it entirely out
of this subgenus.

288 University of Califurnia Publications in Geology [Vou.7

University of California Locality 1853. Named in honor of
Mr. Storms, State Mineralogist, California State Mining Bureau,
who very kindly loaned us several of Dr. Cooper’s type speci-
mens. This species resembles Caricella pyruloides Conrad of the
Alabama Claiborne very closely.

Dimensions: Length, 15mm; width of body-whorl, 6mm.

PHOS(?) MARTINI, n.sp.
Plate 18, figure 5

Shell, bucciniform with very sharp spire, whorls seven and a
half; the first three smooth, minute; fourth, fifth, and sixth
marked by vertical ribs crossed by three revolving riblets which
form a beaded structure at intersection. The vertical ribs num-
ber twelve on the fourth, fifteen to sixteen on the fifth, and
eighteen or twenty on the sixth whorl. The revolving and vertical
ribs are the same in strength on the body-whorl. The inner lip,
crenulated ; columella smooth. Canal unknown, but is probably
short and narrow.

University of California Locality 1853. Named in honor of
Mr. Bruce Martin, Assistant Curator, California Academy of
Sciences.

Dimensions: Length, 11mm; width of body whorl, 7mm.

CALLIOSTOMA(?) ARNOLDI, n.sp.

Plate 14, figures 5a, 5b, and 5c

Shell conical, with moderately angulated base. Whorls, num-
ber six the first two, turbinate. The second, third, fourth and
fifth whorls are marked by three nodose revolving lines while the
body-whorl has six, five of which are continuous on the base. A
part of the body-whorl is broken, making an accurate descrip-
tion of its base impossible. The body-whorl is about one and
one-half times the penultimate whorl. Aperture, subquadrate.
The apical angle of this species is very small in comparison with
many species of this genus.

University of California Locality 1853. Named for Dr. Ralph
Arnold.

Dimensions: Length, 6mm; width of body-whorl, 3mm.

1913] Dickerson: Fauna of Eocene at Marysville Buttes 289

BITTIUM LONGISSIMUM Cooper

Bittium longissimum.—Cooper, J. G., Catalogue of California Fossils,
Bull. 4, California State Mining Bureau, p. 45. 1894.

‘“‘Exceedingly long compared to its diameter; first three or four
whorls regularly convex, smooth; the remaining thirteen with ten to
fourteen vertical riblets crossed hy three revolving ones, which caneellate
the surface uniformly; the anterior riblet iargest, thus giving the whorl
a turreted form; mouth quadrilateral, simple (the basal surface cannot
be seen), Length, 0.55 inch; breadth, 0.06; mouth, 0.03. The shell had
at least sixteen whorls, and the smoothness of the upper ones may be
due to erosion. It much resembles the living B. asperum Gabb (stouater
with thirteen whorls), a variety of which is also turreted. (See Pal.
of California, 11, p. 12, pl. 2, f. 20). Marysville Buttes, only found by
Mr. Watts.’’

CARDIUM DALLI, n.sp.
. Plate 14, figures 4a, 4b, and 4c

Shell, thin, broad, cordate, equilateral, beaks central, prom-
inent, approximate; hinge-line, nearly straight. Anterior and
basal margins form a regular curve; the posterior margin is
straight. The surface is marked by minute rounded, radiating
ribs excepting on the posterior face of the shell which is covered
by about 25 larger ribs rounded on their posterior sides and
granulated on their anterior sides. These larger ribs are set off
from the finer ribs by a sharp angle which extends from the
beak to a point on the basal margin a fifth of the distance from
the posterior margin. The posterior face is decidedly concave.
The immature forms are frequently bluish on the beaks. The
concentric lines of growth are as prominent as the ribs. This
vives the shell surface a beautiful reticulated appearance.

University of California Localities 1853 and 1856.

Named in honor of Dr. W. H. Dall, Palaeontologist, Smith-
sonian Institution.

This species differs from Cardium cooper: Gabb in having
larger granular ribs on the posterior face distinctly set off from
the finer ribs on rest of the shell. Its ornamentation is entirely
different from that of Cardium brewert Gabb but the shape is
somewhat similar. The posterior margin is straight in (. dalli,
n.sp., while that of (. coopert is rounded.

Dimensions: Height, 18mm; length 17mm.

290 University of California Publications in Geology [Vou.7

GLYCIMERIS MARYSVILLENSIS, n.sp.
Plate 14, figures la and 1b

Shell, small, subglobose, almost equilateral; beak small, in-
curved and central. Cardinal margin, straight; the anterior and
posterior margins, regularly rounded. Surface marked by prom-
inent concentric ribs. Hinge marked by eleven teeth. Area
trigonal, small.

University of California Locality 1853. Named for the oceur-
rence at Marysville Buttes in which the type specimen was found.

Dimensions: Height, 5mm; length 5mm.

NUCULA COOPERI, n.sp.
Plate 14, figures 2a and 2b

Shell, small, rounded triangular; small rather prominent
beaks located about a third of the length from the anterior end
and inelined forward. Cardinal margin nearly straight, sloping
rapidly to the posterior margin; anterior end truncated, ex-
cavated under the beaks, shghtly concave and united with the
basal margin by a sharp angle; basal margin evenly rounded;
posterior end narrowly rounded. Surface marked by many
minute lines of growth and by small radiating ribs. Hinge
robust, pit, very small. This species resembles Nucula solitaria
Gabb of the Chieo group closely, but the radiating ribs of this
form readily distinguish it.

University of California Locality 1853. Named in honor of
Dr. J. G. Cooper, who first deseribed species from this locality.

Dimensions: Height, 6mm; length, 8mm.

TELLINA SUTTERENSIS, n.sp.
Plate 14, figures 3a and 3b
Shell, oblong, compressed, thin. Beaks prominent, being
located about one-third of distance from the anterior end. An-
terior and posterior extremities rounded; the anterior dorsal
margin slopes from the beaks more steeply than the posterior
dorsal margin. Surface marked by minute lines of growth.
University of California Localities 1853 and 1856. Named for
the occurrence in Sutter County, California.
Dimensions: Height, 6mm; length, 8mm.

1913] = Dickerson: Fauna of Eocene at Marysville Buttes 291

TROCHOCYATHUS(?) PERRINI, n.sp.
Plate 14, figures 6a, 6b, and 6¢

Form short, trochiform. Cross-section, elliptical. Base at-
tached by a small short pedicel which is now broken from the
type. Costae distinet, granular or even nodose, and correspond-
ing to all eyeles of septa. Septa in four eyeles. Pali appeared
to be present, but not clearly shown. Columella, fasicular ( ?)
indistinet. Calice, shallow.

Only one specimen was found at University of California
Loeality 1853.

Named in honor of Professor James Perrin Smith of Stan-
ford University.

Dimensions: Height, 6mm; width, 6mm.

EXPLANATION OF PLATE 11

Eocene of Marysville Buttes
. Turris monolifera (Cooper). 3.

. Turris monolifera (Cooper). 3.
Turris andersoni, n.sp. 4.

Sureula clarki, n.sp. 4.

Sureula crenatospira Cooper. 2.

Turris inconstans (Cooper). 4.

a. Turris suturalis (Cooper). 2.

. Turris suturalis (Cooper). X2.

7a. Turris perkinsiana (Cooper). X2.

. Detail of decoration of figure 7a.
Drillia ullreyana Cooper. X93.
Sureula holwayi, nsp. 4.

. Terebra wattsiana Cooper. X 4%.

. Fusinus lineatus, n.sp. 4.

[292]

[DICKERSON] VOL. 7. PL. 11

UNIV. CALIF. PUBL. BULL. DEPT. GEOL.

pre

*, (OG.

EXPLANATION OF PLATE 12

Eocene of Marysville Buttes

Siphonalia sutterensis, n.sp. 2.

2a. Cancellaria stantoni, n.sp. back view. X23.

. Cancellaria stantoni, n.sp. mouth view of smaller specimen. X 4.

. . . ~ 4
Cordiera gracillima Cooper. 5.

Astyris, sp. 4.

. Voluta lawsoni, n.sp., mouth view. X2.

. Voluta lawsoni, n.sp., back view. X2.

. Voluta lawsoni, n.sp., top view. X2.

. Surecula davisiana (Cooper) type specimen. X2.

. Sureula davisiana (Cooper) smaller specimen showing body

whorl. 4.
Detail of body whorl of Fig. 6b.
Clavella tabulata, n.sp. xX %.

Cancellaria irelaniana Cooper, type specimen, natural size.

[294]

[DICKERSON ] VOL. 7. PL. 12

PUBL BUEE DEPT. GEOL.

UNIV. CALIF

Hf semester ctarareertere

EXPLANATION OF PLATE 13

Eocene of Marysville Buttes

Olivula marysvillensis, n.sp. x4.

Olivula marysvillensis, n.sp. ae
Architectonica weaveri, n.sp., top view. 2%.
Architectonica weaveri, n.sp., side view. 2.
Caricella stormsiana, n.sp., mouth view. X2.
Caricella stormsiana, n.sp., back view. 2.
Oliverato californica Cooper, back view. X3.
Oliverato californica Cooper, mouth view. 3.

Phos(?) martini, nsp. 2.

Turritella merriami, n.sp., spire of young specimen.

Turritella merriami, n.sp., back view of lower whorls.

Turritella merriami, n.sp. 2.

[296]

[DICKERSON J] VOL. 7. PL. 13

WINIVe CALIES PUBE: BULL. DEPT. GEOL.

fpeseenereeerearithnnnrnenenter enema

fone era nnenemenf

ite)

. View showing umbones of Fig. 3a.

EXPLANATION OF PLATE 14

Eocene of Marysville Buttes

. Glycimeris marysvillensis, n.sp. x4.

. Glycimeris marysvillensis, n.sp., looking down upon the um-

bones. 4.

. Nucula cooperi, n.sp., view showing hinge. 4.
. Nucula cooperi, n.sp., back view. X4.

. Tellina sutterensis, n.sp. X93.

. Cardium dalli, n.sp. 2.

. Cardium dalli, n.sp., view showing umbone. X2.

. Detail of Fig. 4a showing the two kinds of decoration.
5a. Calliostoma(?) arnoldi, n.sp. 4.

. Top view of Fig. 5a. x4.

*, Detail of decoration of Fig. 3a.

. Trochocyathus(?) perrini, n.sp., side view. 4.

. Trochocyathus(?) perrini, n.sp., base view. X4.

*. Trochoeyathus(?) perrini, n.sp., top view. 4.

Synechodus, sp. 2.

[293]

[DICKERSON ] VOL. 7. PL. 14.

UNIV. CALIF, PUBL. BULL. DEPT. GEOL.

HE DEPARTMENT oF

GEOLOGY

Issued June 12, 1913

cM
BY

ROBERT W. PACK : ee.

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UNIVERSITY OF CALIFORNIA PRESS <3 : 3

BERKELEY

UNIVERSITY OF CALIFORNIA PUBLICATIONS

Norr.—The University of California Publications are offered in exchange for
eations of learned societies and institutions, universities and libraries. Complete
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Otro HARRASSOWITZ — R. FRIEDLAENDER & SOHN es AGP 8
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aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany, Geology,
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Cited as Univ. Calif. Publ. Bull. Dept. Geol.
Volume 1, 1893-1896, 435 pp., with 18 plates, price......-..-.----c--cesseceeeeseceeceecveceenceessas
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Fs A list of the titles in volumes 1 and 2 will be sent upon request.

VOLUME 3.

. The Quarternary of Southern California, by Oscar H. Hershey -2-(0.....c2--:cecccece-teen see
Colemanite from Southern California, by Arthur S. Hakle.........--.:c:ctcecceeecece-eeeeee ee a
. The Eparchaean Interval. A Criticism of the use of the term. Algonkian, by
Andrew: C, Lawson 2.25. csesc2biot nck. hence tice teins etc ee eae ene gies
. Triassic Ichthyopterygia from California and Nevada, by John C. Merriam..........
A Contribution to the Petrography of the John Day Basin, by Frank C. Callkins...... :
The Igneous Rocks near Pajaro, by. John AY Reid-)-... 2 -0..-5).20 eer eee
. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller
. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by
Andréyw «OC. Lawsolv sthsctiec ne ec ee et es Ramee enero a ah ie Pee 10ers
» Palacheite, by Arthur S. Halkless:.. 1.252. cce.5- occa toca eae 10cm
. Two New Species of Fessil Turtles from Oregon, by O. P. Hay. ;
. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair.
Nos. 10 and 11 in one covet............-.-. ent cLawestac Ges onadetn eee teas ae nee a Soe 10¢
12. New Ichthyosauria from the Upper Triassie of California, by John C. Merriam........ ‘
. Spodumene from San Diego County, California, by Waldemar T. Schaller... é
. The Pliocene and Quaternary Canidae of the Great Valley of California, by

aioe
BoD ONAN whre

He
i OO

Jolin GC, Merriam’ 2. 22caa2:c222ct: -coesncebapee coe cte se Siena a ee oe ee se, ope
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson..................- 69€
16. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam... 05¢
17. The Orbieular Gabbro at Dehesa, San Diego County, California, by Andrew C. ig

TS WOT oo wcche enccta nse nec n dsebe eae oe toro Sone Bene ep etn ace ee Bea oe ae ae é
18. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. Evans
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmon
20. Euceratherium; a New Ungulate from the Quaternary Caves of California, by

William J. Sinclair and H, L. Furlong. .....--------2-----:ceccsense-ne-cnseceneneenenemeeecenenenenennceneaenss
21. A New Marine Reptile from the Triassic of California, by John C. Merriam..........
22. The River Terraces of the Orleans Basin, California, by Oscar H. Hershey...
VOLUME 4. es
. The Geology of the Upper Region of the Main Walker River, Nevada, by Dwight —
PDS rn Bn ean ae ae rece ca a ee soon Rees
A Primitive Ichthyosaurian Limb from the Middle Triassie of Nevada, by John
Co Merriam oon. nen e-ceneecenceeeeceeceececeneneecencencenennscceneeceeeenesnsntensnsenetecensneresscamunnenenanpennnecnaneennens
Geological Section of the Coast Ranges North of the Bay of San Francisco, by
Vi CO, OSMONE «nen eececeececececeececeeeeecnenennncenenseeecnesenernersscensnesnansnnsnensnncnsnsnansesensusnetnaansancnaasseasssses
. Areas of the California Neocene, by Vance C. OSmont........---------------200---eneencoceenssosseneceseee

. Contribution to the Palaeontology of the Martinez Group, by Charles E. Weaver
. New or Imperfectly Known Rodents and Ungulates from the John Day Series, by

William J. Simelair ...-..-----scccsccecceceeeseceecsscsneseceesoeesenerneceerenencnnencenenes eovaeesenerenenneeennneneones
New Mammalia from the Quarternary Caves of California, by William J. Sinclair
. Preptoceras, a New Ungulate from the Samwel Cave, California, by Eustace L

Purlong -....----2c2c-c-cesecececececeeceeccnseeecnenssannennnsnseccestecnensesnenencansanersncncsene pideericerceeneasdstccss sesso

ON ANF WwW pm

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 13, pp. 299-304, pl. 15 Issued June 12, 1913

NOTES ON SCUTELLA NORRISI AND
SCUTASTER ANDERSONI

ROBERT W. PACK}

In 1909 the writer published a few notes on the Tertiary
Echinoids of California, describing several new species and the
new genus Scutaster.2 Since this paper was written more nearly
perfect specimens of Scutella norrisi and Scutaster andersoni
have been obtained. The writer therefore takes pleasure in fur-
nishing more complete figures of these species than it was possible
to give at the time the type descriptions were written, together
with a few notes to supplement the original descriptions.

SCUTELLA NORRISI Pack
Plate 15, figure 1

Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 277, pl. 23, fig. 3, 1909.

The original description is as follows:

Test sub-circular in general outline, with deep, broad, marginal notches
in the edges of the ambulacral areas. The two posterior notches are much
deeper than are the anterior ones, and truncate the posterior interambu-
lacral space on either side of the median line, shaping the posterior end
of the test into a prominent process. The test when viewed from above
has a leaf-like appearance. Test much depressed, edges markedly thin,
abactinal surface very slightly arched, apex central; actinal surface flat
or gently concave. Mouth central, slightly sunken; ambulacral furrows
poorly shown in the specimens examined, but evidently branch but little,

1 Published by permission of the Director of the United States Geolog-
ical Survey.

2 Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, pp. 275-283, 1909.

300 University of California Publications in Geology [Vou.7

if at all. Main ambulacral grooves continue from the mouth to the margin,
entering the marginal notches. Anal pore small, inframarginal. Ambu-
lacral star central. Petals extend about three-fourths the distance to the
margin and not entirely closed at the ends.

Examination of the new material has brought out the fol-
lowing points: The test is sub-cireular to sub-pentagonal in
outline, resembling somewhat a maple leaf. The outline is ren-
dered undulatory both by the deep notches in the extremities of
the ambulacrae and by shallow indentations of the margin near
the junction of the ambulacral and interambulacral areas. The
abactinal surface is very slightly arched, and the slope from the
margin to the apex is regular. The petals extend about two-
thirds the distance from the center to the margin, and show
only a slight tendeney to close. The apical system is central. The
size and peculiar outline of this species are sufficient to differen-
tiate it from other west coast forms. Scutella merriami Anderson
shows shallow marginal notches in the extremities of the posterior
ambulacrae, and in rare eases the notches become deep enough
to shape the test into an outline similar to that of S. norrist.
The greater size of the latter species is, however, sufficient to
differentiate it.

Occurrence: Eastern Monterey County near the Stone Can-
yon mine; San Luis Obispo County, at Panza, on the San Juan
River, and in the mountains between the San Juan River and
the Carrizo Plains; Orange County, in the San Joaquin Hills
south of Santa Ana.

This species is characteristic of the Lower Miocene.

Dimensions: Diameter through the anterior petal about 75
mm. Height 6 to 7 mm.

Genus SCUTASTER Pack

Uniy. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 270, 1909.

The original generic deseription is as follows:

Test circular, depressed, ambulacral star small. Lunules in the pro-
longation of the petals of the trivium; and either lacking in the bivium
and posterior interambulacral space, or not placed in the same relative
positions as on the anterior portion of the test.

1913] Pack: Scutella norrisi and Scutaster andersoni 301

The new material shows that lunules and narrow marginal
notches are lacking in the prolongation of the posterior petals
and in the posterior interambulacral area, as was suggested in
the original description.

SCUTASTER ANDERSONT Pack

Plate 15, figures 2a and 2b

Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, pp. 278-279, pl. 23, 1909.

The original deseription is as follows:

Test sub-eircular in outline, edges markedly thin. Upper surface regu-
larly arched from the margin; apex anterior to the center. Apical system
small and apparently central. Ambulacral star small; petals extending
slightly less than half way to the margin of the test, closed at the ends.
Lateral petals broader than the posterior ones, but of almost the same
length. Poriferous zones broad, and continuing full width almost to the
ends of the petals. In the posterior petals the interporiferous area forms
about one-third the width of the petal. Poriferous zones of the lateral
petals equal in width to those of the posterior petals, but enclosed area
broader. In the extension of the three anterior petals are broad lunules,
over half as long as the petals; shallow grooves extend from the lunules
to the margin. Anterior lunule slightly farther from the apical system
than are the lateral ones. From the ends of the posterior petals the
plates enlarge, and the area broadens rapidly. No lunules were seen here,
nor in the posterior interambulacral space. They may be represented by
marginal notches, as the posterior edge of the specimen is lacking.

The new material shows that the test is sub-cireular to oval
in outline. The apical system is slightly posterior to the middle
of the test, the ratio of the distance from the apical system to
the posterior and anterior margins in the figured specimen is
as 23:30. The middle of the arch of the abactinal suface is
shehtly anterior to the middle of the test, being located approx-
imately in the middle of the anterior petal. In the figured
specimen the distance from the middle of the arch to the anterior
margin is 21 mm., to the posterior margin 32 mm. The posterior
ambulacrae terminate rather abruptly, the edge of the test form-
ing broad, shallow notches which fashion the posterior interam-
bulacral area into a process somewhat similar to that of Scutella

norrist. The test is much compressed. In some eases there is a

302 University of California Publications in Geology [Vou.7

slight tendency for the arch of the abactinal surface to flatten
near the lateral margins, but in most cases the profile of the
upper surface is regular between these margins. The slope of
the abactinal surface from the apex to the anterior margin is
rounded and rather abrupt, to the posterior margin flat and _
gentle. There are neither lunules nor narrow marginal notches in
the posterior half of the test. The petals are almost closed, the
outer row of pores swinging in abruptly toward the inner row.
The posterior petals are slightly shorter as well as_ slightly
narrower than the lateral ones. Isolated pores are visible for
only one or two plates beyond the outer end of the petals. The
greatest width of the test is posterior to the center, and approxi-
mately through the apical system.

Occurrence: Near Muir, Contra Costa County, California;
in Kern County, California, on the north slope of the San Emig-
dio Mountains at the southern end of the San Joaquin Valley.
At the first locality only a single specimen has been found; at
the second the tests occur in great abundance.

Known only in the lower half of the Miocene.

Dimensions: Diameter through the anterior petal 53 mm.;
diameter between the lateral margins 62 mm.; height 5 to 6 mm.

Transmitted January 15, 1913.

EXPLANATION OF PLATE 15
Fig. 1.—Scutella norrisi Pack. View of abactinal surface. Natural size.

Diameter through anterior petal, about 75 mm. Occurrence, near the
mouth of the Alizo Canyon, in the southern end of the San Joaquin Hills,
south of Santa Ana, Orange County, California. University of California
locality 1157.

Figs. 2a and 2b.—Scutaster andersoni Pack. Natural size.

Fig. 2a. View of abactinal surface. Diameter through anterior petal,
53 mm. Occurrence, in the Mount Pinos Quadrangle, California, at the
southern end of the San Joaquin Valley, about three and three-quarters
miles northeast of Antimony Peak.

Fig. 2b. Anteroposterior section.

[304]

UNIV GALLE PUBEY BUELL. DEPT; GEOL: [RACKIVOIN= 7 aemlo

el 2b

TIN OF THE DEPARTMENT OF

GEOLOGY
Issued May 24, 1913

‘ BY
JOHN C. MERRIAM

~ UNIVERSITY OF CALIFORNIA PRESS

BERKELEY :
*
ete haa Ly aera ee 3
<agonian SE Be ¥
aS - sf
(a
i913 %
naire,” Ix

é #2
NotE.—The University of California Publications are offered in exchange for t
cations of learned societies and institutions, universities and libraries. Complete
all the publications of the University will be sent upon request. For sample copies, lists of
publications and other information, address the Manager of the University Press, Berkel
California, U. S. A. All matter sent in exchange should be addressed to The Exch
Department, University Library, Berkeley, California, U. S. A. ¢’

OTTO HARRASSOWITZ R. FRIEDLAENDER & SOHN ~
LEIPZIG BERLIN ;

Agent for the series in American Arch- Agent for the series in American .
aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany, Geo!
Edueation, Modern Philology, Philosophy, Mathematies, Pathology, Physiology
Psychology. j Zoology, and Memoirs. ; es

Volumes 1 (pp. 435), II (pp. 450), III (pp. 475), IV (pp. 462), V (pp. 448),
completed. Volumes VI and VII (in progress).

Cited as Uniy. Calif. Publ. Bull. Dept. Geol>—~
Volume 1, 1893-1896, 435 pp., with 18 plates, price............c1..------.-0-
Volume 2, 1896-1902, 450 pp., with 17 plates and 1 map, price

A list of the titles in volumes 1 and 2 will be sent upon request.

VOLUME 3. _

1. The Quarternary of Southern California, by Oscar H. Hershey ~.....-.2-..2.-2-c:2-c--e-nenee 20

2. Colemanite from Southern California, by Arthur S. Hakle_. ee

3. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by —
Andrew G,. Dawsons si.i.--c-i ie eth on ee :

4, Triassic Ichthyopterygia from California and Nevada, by John C. Merriam... a

5. A Contribution to the Petrography of the John Day Basin, by Frank C. Calkins...

6. The Igneous Rocks near Pajaro, by John A. Reid......-...-------senee ee ie Saeed Sache

7. Minerals from Leona Heights, Alameda Oo., California, by Waldemar T. Schaller 15¢ ~

8. Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, California, by =~
Andrew. C.. Gra Won |. scccn-c2tecencosecceccocen uote mepeen eee ate ene ec nate oa a re societies See :

9. Palacheite, by Arthur’ S; Baklez 2. ous a ee ee Reh estes ee 10¢
0. Two New Species of Fessil Turtles from Oregon, by O. P. Hay. :
1. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair.
Nos. 10 and. 11-in one Coversiz eS eee
12. New Ichthyosauria from the Upper Triassie of California, by John C. Merriam........
13. Spodumene from San Diego County, California, by Waldemar T. Schaller...
14, The Pliocene and Quaternary Canidae of the Great Valley of California, by
MORN’ CyAMOrviAM seca ean nn chet ceases een ee eis a Bee ceva
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson...............
16. A Note on the Fauna of the Lower Miocene in California, by John C. Merriam......
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew C. —
LQ WSOD, eeececesecvennccnsnceenceceeeceeececenencneceascencnansearancesenscanseatdnepeseansseanaesedtmenassnrasdensams====nesZaeeeaeaeee
’ 18. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert :
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmon 1
20. Euceratherium, a New Ungulate from the Quaternary Caves of California, by

William J. Sinclair and E. L. Furlong................------ secveeceeceeeceensecnenneeecteceenceoneeennensetnnaes
21. A New Marine Reptile from the Triassie of California, by John C. Merriam...
92. The River Terraces of the Orleans Basin, California, by Oscar'-H. Hershey...
VOLUME 4. : ae
1. The Geology of the Upper Region of the Main Walker River, Nevada, by Dwight —
TD, Qrithy .n.n-caeoccceneececenese-naceceessaecteendesecuececanecsanenesteneqsansasevasensequtenanenshcecnnansarencmnsnenaZ=reseneeee
_ A Primitive Ichthyosaurian Limb from the Middle Triassic of Nevada, by Jo
Cl. Merriam ....-.---.--.--2---ccecceeceeeccneceemer scence cceeeescneeeescennesnuacnnsreceeresnnesnecceresmesnnansecnnanancsnsea
Geological Section of the Coast Ranges North of the Bay of San Francisco,
Vi. CO. OSMONA ooie.eesnenn-ne-ecceeececeeceecenneeeneece scene cccneeceseaaennens cnaaesecasarsaenccnsnecnnnanracsnacaanes
. Areas of the California Neocene, by Vance C. Osmont......------2+--swees-weseremnnnnns

Contribution to the Palaeontology of the Martinez Group, by Charles E. Wea
New or Imperfectly Known Rodents and Ungulates from the John Day Series, |

William J. Simelair ~....---.---i----ee-c-neseeecnceeen en eneneee sc neececnee erent entnenmene ba
New Mammalia from the Quarternary Caves of California, by Willham
. Preptoceras, a New Ungulate from the Samwel Cave, California, by Eust

Prong © -n-c-------nnecncasecscece see ennsesnneenemnnnecaccerdeaseenecatimnanenndnensec7 cater tnnanceasataaese

SI Auk w& pw

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 14, pp. 305-323 Issued May 24, 1913

THE SKULL AND DENTITION OF A CAMEL
FROM THE PLEISTOCENE OF
RANCHO LA BREA

JOHN C. MERRIAM

CONTENTS

PAGE
TEs xa, a a ma oP 305
SUN a a a ee 308
TOYA ETU OY, » a ee ee 313

Relation of Rancho La Brea Specimens to Previously Described
Pleistocene Forms from North Ameria, .............2....12--:0--0--cc-cceeceeeeeeeeee 317
Comparison with Type Specimen of Camelops .............-..----------- 318

Comparison with Type Specimen of Auchenia hesterna Leidy. 318
Comparison with Texas Forms Referred to by Cope as Holo-
meniscus hesternus, H. suleatus, H. vitikerianus, and H.

IMACT OCC PN AUS. Ae ses aceectee se ctesatceecsecnce socacescuasaceasaiecussteneaeceuteas Seccenceczee 321
BS UREN T NY se te See tea Te ae neo an oe Peas sys cdcneneSeaicetee fectettecco ses Sebccesseccce ee Ook

INTRODUCTION

Although remains of camels are fairly common in the Pleisto-
eene of North America, and are widely distributed over the
continent, up to the present time the material obtained has been
very fragmentary, and the available information correspondingly
unsatisfactory. So far as known to the writer, the best speci-
mens described consist of small parts of the skeleton, the skull
being represented by jaws and very incomplete cranial material.

Owing to the nature of the material available, the North
American Pleistocene Camelidae have almost necessarily been

306 University of Califorma Publications in Geology (Vou.7

described under numerous generic and specific names, as the
fragmentary specimens representing different parts of the skele-
ton cannot be correlated satisfactorily. Not less than six genera
are listed. It is probable that three of the generic groups have
a valid basis in American material.:The others are of doubtful
value. The forms referred to Hschatius and Camelus represent
two of the generic groups. The relationships of the species
referred to Camelops, Megalomeruc, Auchenia and Holomeniscus,
present one of the problems in the study of this group, recent
writers generally considering the four as representing a single
genus,

Wortman' in his revision of the extinct Camelidae of North
America called attention to the very fragmentary nature of
the material upon which all of the North American Pleistocene
species rest, and considered that no evidence had been presented
showing that valid characters separated the genera Megalomeryx
and MHolomeniscus from Camelops, the first genus described.
The North American forms referred to Auchenia he showed to
be distinct from the Recent Auchenia, and not clearly separable
from Camelops. Megalomerya was deseribed from Nebraska later
than Camelops from Kansas, and may be of Tertiary age. It was
based upon two molar teeth, while the tvpe of Camelops consisted
of an anterior end of the rostral region without cheek teeth.
Holomeniscus was characterized by Cope as possessing a single
superior premolar, P*. Wortman stated that, so far as he had
been able to obtain information, in the only specimen in which
‘the superior premolar formula can be determined, both P* and
P* are present. So far as determined by Wortman, no characters
were presented which might reasonably be considered as dis-
tinguishing Holomeniscus from Camelops.

In the excavation work done at Rancho La Brea during the
past six vears camel material has been found occasionally, but
not until recently has it been possible to obtain a complete skull.
In the exeavations of the last few months, the University of
California has been so fortunate as to find several nearly perfect
skulls, and associated with them is a quantity of skeletal material
representing the greater part of the animal. Three skulls now

1 Wortman, J. L., Bull. Am. Mus., vol. 16, p. 128, 1898.

1913 | Merriam: A Camel from Rancho La Brea 307

Fig. 1. Camelops hesternus (Leidy). Skull, superior view. No. 20040,
x ¥%. Rancho La Brea Beds.

Fig. 2. Camelops hesternus (Leidy). Skull, inferior view. No. 20040,
x ¥. Rancho La Brea Beds.

Fig. 3. Camelops hesternus (Ueidy). Superior view of anterior portion
of the mandible with dentition. No. 20040, x 4%. Rancho La Brea Beds.

308 University of California Publications in Geology [Vou.7

available in the palaeontologiec laboratory furnish for the first
time a satisfactory basis for comparative study of the skull and
dentition of our American Pleistocene camels. In advance of an
investigation of the entire representation of the skeleton the
following descriptions are presented. A discussion of the
skeleton will be furnished after completion of the excavation
work, when all materials of this group can be brought together
for more satisfactory study.

SKULL

The skull in specimens 20040, 20028, and 20049 approximates
the size in that of the Bactrian camel. The general outlines
resemble Auchenia more nearly than Camclus. In superior view
(figs. 1 and +), the slender rostral region tapers more gradually
toward the anterior end than in Camelus, and in this respect
resembles Auchenia. The frontal region is quite distinctly convex
transversely, with no median depression, and in this character
differs from the specimens of both Auchenia and Camelus avail-
able for comparison. The orbits are situated relatively far back,
the anterior border being situated above the last superior molar.
The basicranial and basifacial axes are nearly parallel, as in
Camelus.

The nasal elements are long and narrow, the posterior ends
are separated by a wedge of the frontals, but the outer borders
do not spread widely as in Auchenia and Camelus. The anterior
ends of the nasals are in broad contact with the premaxillaries,
as In Auchenia. The nasals ave relatively longer and narrower
than in Auchenia, and the notch for the posterior border of the
anterior nasal opening is not behind the posterior end of the
premaxillaries. In Auchenia the posterior ends of the pre-
maxillaries do not extend as far back as the posterior border of
the anterior nasal opening. The ends of the nasals project
anteriorly beyond the superior border of the premaxillaries.

A characteristic feature of the Rancho La Brea specimens is
the presence of a large, deep fossa near the upper margin of each
maxillary above the fourth premolar (fig. 5). The inferior
region of this fossa is not sharply marked. The upper wall of

1913 | Merriam: A Camel from Rancho La Brea 309

Fig. 4. Camelops near hesternus (Leidy). Skull, superior view. No.
20028, x ¥%. Rancho La Brea Beds.

Figs. 5 and 6, Camelops near hesternus (Leidy). Skull. No. 20028,
x ¥. Raneho La Brea Beds. Fig. 5, cranium, lateral view; fig. 6, man-
dible, lateral view.

310 University of California Publications in Geology [Vou.7

the cavity is abrupt in no. 20040 and is bordered by a sharp
overhanging ridge in nos. 20028 and 20049. This fossa is clearly
shown in Pliauchenia (Megatylopus) gigas described by Matthew
and Cook? and is strongly marked in Alticamelus.* There is no
suggestion of it in Auchenia or in Camelus.

The lachrymal vacuities are very large and have an approxi-
mately triangular outhne. In specimen 20028 the lachrymals
are separated externally from the lachrymal vacuities on one
side by the union of the maxillaries and frontals. In no. 20040
they barely touch the vacuities.

The heavy anterior end of the zygomatic process of the
squamosal extends forward well beneath the posterior border of
the orbit somewhat as in Auchenia, but in contrast to the form
in Camelus. The jugal is much thicker vertically below the
orbit than in Camelus, and exhibits a marked inferior crest or
ridge as described in Megatylopus gigas by Matthew and Cook.*

The palate is narrow (figs. 2 and 9), the long, narrow, V-
shaped posterior nasal opening extending forward to a point
slightly in advance of a line connecting the middle region of the
third upper molars in nos. 20028 and 20049, and to the posterior
end of M? in no, 20040.

The basiphenoid and presphenoid form a deep narrow ridge
quite different from tbe inferior surface of this element in
Camelus and in Auchenia. The inferior processes of the ali-
sphenoid seem smaller, are less divergent, and do not project as
far inferiorly as in Camelus. i

The glenoid fossa is relatively narrower posteriorly than in
Camelus, and as in Auchenia, the outer margin of this fossa is
not bordered by a distinctly elevated wall or process that 1s seen
in Camelus. The postglenoid process is somewhat larger than in
Auchenia. 2

In specimen 20028 the transverse palato-maxillary suture
truncates the anterior ends of the palatines rather broadly, as in
Camelus dromedarius. In no. 20049 the suture is more strongly

2 Matthew, W. D., and Cook, H. H., Bull. Am. Mus. Nat. Hist., vol. 26,
p. 397, 1909.

3 Tbid., p. 403.

4 Ibid., p. 398.

1913 ] Merriam: A Camel from Rancho La Brea aula

convex anteriorly. In no. 20040 it is still more acute anteriorly.
In Auchenia lama the anterior ends of the palatines extend
forward as an acute wedge between the maxillaries.

The paroccipital process is rather slender, and bends forward
with a marked inferior hook. In Auchenia this process is wider
distally. The mastoid region forms a deep and rather narrow
plate anteriorly. The mastoid and _ paroccipital plates are
brought nearer together than in either Auchenia or Camelus. In
nos. 20040 and 20028 the posterior inferior border of the mastoid
plate slopes forward quite sharply in contrast to the form seen
in Auchenia.

The occipital region (fig. 7) shows rather more similarity to
Camelus than to Auchenia. In Auchenia the occiput consists of

Fig. 7. Camelops near hesternus (Leidy). Occipital region of the
skull. No. 20028, x 15. Rancho La Brea Beds.

two lateral planes which meet in a strong median crest. At the
outer borders of these planes are the lateral foramina of the
occiput. In the Rancho La Brea specimens there is a short low
median erest at the upper end of the occiput in nos. 20028 and
20040; in no. 20049 it is searcely visible. On each side of the
crest is a deep fossa for the rectus capitis posticus. At either
side of the occiput the large lateral foramina lie at the bottom
of large, deep fossae, and these foramina deeply notch the
margins of the occipital bone. Between the lateral foramina
and the fossae for the muscles below the inion the occipital bone
rises on each side as a prominent rounded buttress or ridge
extending from near the upper border of the foramen magnum

312 University of California Publications in Geology [Vou.7

to the lamboidal crest. The region of the occiput immediately
above the foramen magnum is moderately convex, approaching
flatness, as in Camelus, instead of strongly convex nearing
angularity, as in Auchenia.

The frontal foramina are a lttle farther apart than in
Camelus. In Auchenia these foramina are relatively larger and
there are distinct channels leading forward from them such as
are not seen in the Rancho La Brea specimens. The infraorbital
foramen and the foramen piercing the root of the zygomatie arch
are situated much as in Auchenia. The infraorbital foramina
consists of a single opening on each side in no. 20028; the open-
ing 1s separated into two parts by a bridge of bone in 20040;
and is divided on one side by a slender bridge in 20049. The
infraorbital foramina are situated approximately over the pos-
terior border of P* in nos, 20028 and 20040, and over the middle
region of M? in no, 20049. The anterior palatine foramina are
long and narrow, and extend back to the canines. The anterior
ends of the maxillaries extending around the borders of these
foramina reach to the anterior side of the openings, as in the
tvpe of Camclops. In Auchenia lama they do not reach as far
forward. The posterior palatine foramina are situated well for-
ward near P* in specimen 20028, and opposite P* in nos. 20040
and 20049.

The postglenoid foramen is very small, in contrast to the large
size of the opening in Camelus. A small foramen present on the
outer base of the postglenoid process is not found in Camelus
and is absent or very minute in Auchenia. The lateral foramina
of the occiput are very large and open externally into the deep
lateral fossae of the occipital region. The anterior mental
foramen of the mandible is immediately below or slightly behind
the canine, as in Auchenia. It is situated farther back on the
horizontal ramus in Camelus.

In the mandible (figs. 3, 6, and 8), the svmphsial region is
relatively short anteroposteriorly, as in Auchema., The sym-
physial union in Camelus is much longer anteroposteriorly
than in Auchenia or in the Rancho La Brea specimens. The
horizontal ramus is somewhat higher than in Camelus, and
slightly higher than in Auchexia. It tapers very gradually

1913 | Merriam: A Camel from Rancho La Brea 313

toward the anterior end. Below the diastema the lower margin
is barely coneave, in contrast with Auchenia, in which it is dis-
tinetly concave. In Camelus the inferior border may show a
distinet concavity between a point below M, and the svmphysis.
The high coronoid process shows a nearly even width or antero-
posterior diameter for the greater part of its height.

MEASUREMENTS OF SKULL

No. 20028 No, 20040

Length, anterior end of premaxillaries to posterior

end of oecipital condyles ................ Sere eee 571. mm. 573.
Length, anterior end of premaxillaries to anterior

end of inferior nasal opening .................2..0.2::22000--- 316.4 318.
Length along median line, anterior end of premaxil-

laries to posterior end of superior molar series.... 341. 362.
Length along median line from anterior border of

premaxillaries to plane connecting anterior bord-

ers of orbits ....02...22222222...... 324.5 329
Greatest width at posterior region of orbits .............. 245. 251
] s
Greatest height of orbits 2.0000. 63.3 61
oS
Least width of brain-case immediately behind orbits — 77. 33.

Least width of rostral region between superior canine

and cheek-tooth Series ........22.22..22:--2-cececeeeeeeeceteceeee 62:9" " ae:
Greatest anteroposterior diameter of right ramus of

Ghepmandible soo: 22 ee eee 452, 469.
Greatest height of mandible below posterior border

(Od OY eg ee ae ele artea ae 109. 103.
Height of mandible below anterior border of P, -...... 60. 61.
Length of diastema between inferior canine and P, 100. 1

DENTITION

Dental formula, I+, C+, P?, M3

The dentition in general shows more resemblance to that of
Auchenia than to any other form.

T* is a little larger than the superior canine. It is a laterally
compressed, recurved, lanceolate tooth quite similar to I? of
Auchenia. The lower incisor dentition was of much the same
type as in Auchenia. I, was at least as large compared with I,
and I, as in Auchenia; it seems distinctly larger than in Holo-
meniscus hesternus from Texas figured by Cope.°

5 Cope, E. D., Geol. Surv. Texas, 3rd, Ann. Rep. for 1891; pl. 21, fig. 4.

314 University of Califorma Publications in Geology (Vor-7

The small superior canines have much the same form as in
Auchenia, but are relatively thicker transversely.

As in Auchema, small papillae which may be present behind
the canines indicate the existence of rudiments of the anterior
premolars.

Fig. 8. Camelops near hesternus (Leidy). Superior view of anterior
portion of the mandible with dentition. No. 20028, * ¥5. Rancho La
Brea Beds.

Fig. 9. Camelops near hesternus (Leidy). Inferior view of anterior
portion of the skull with dentition. No. 20028, « Ys. Rancho La Brea
Beds.

See also for dentition, figs. 2 and 3, p. 307.

P® as shown in no. 20040 (fig. 2) has a narrow, almost blade-
like crown with a very small cusp, or a prominent ridge of the
cingulum high up on the postero-internal wall. It shows approxi-
mately the same size compared with P* that is noted in Auchenia.

Pt has a relatively greater transverse diameter than in
Auchenia and a more distinetly quadrate form. In this respect,
it more closely approaches the form seen in Camelus.

1913 | Merriam: A Camel from Rancho La Brea 315

Lower premolar four has approximately the same relation to
M, in dimensions as in Auchenia. It has a wedge-shaped cross-
section and approximates the form in Auchenia. There is a deep
enamel fold on the posterior side of the crown, as in Auchenia,
but the inner or medial side is an almost even vertical wall
without the folds seen in Auchenia. P, shows some evidence of
division of the root into two parts, and a faint groove on one
side may mark the line of separation.

The upper molars all differ somewhat from those of Auwchenia
in the less marked development of the external styles and of the
median ribs on the outer side of the paraconid and metaconid.
In M? the anterior Jobe has a noticeably greater transverse
diameter than the posterior lobe. On the somewhat worn M* of
no. 20028 the metastyle is drawn out posteriorly as a wing not
shown in Auchenia. This wing does not appear in the unworn
M?* of no. 20040.

_In M, and M, the inner walls of the protoconid and hypo-
conid lobes tend to be a httle more distinetly separated by a
median longitudinal groove than in Camelus. The styles and
inner ribs of the lower molars are less strongly developed than
in Auchenia. M, and M, differ markedly from the correspond-
ing teeth of Auchenia in the absence of the anteroexternal but-
tresses so characteristic of that genus. It is upon this character
that Wortman® separates Camelops from Auchenia. M, is dis-
tinguished from that cf Camelus by the position of the posterior
or third lobe. In the Rancho La Brea specimens this lobe
extends nearly straight back, and its inner wall is nearly even
with that of the anterior lobes of this tooth. In Camelus the
inner wall of the posterior lobe turns sharply out and away from
the nearly even plane formed by the inner walls of the first and
second lobes. In Auchemwa the posterior lobe of M, rises from
approximately the middle of the posterior end of the second lobe,
and is separated from the inner and outer walls of the second
lobe by a deep longitudinal groove on each side.

6 Wortman, J. L., Bull. Am. Mus. Nat. Hist., vol. 10, pp. 129-130, 1898.

316 University of California Publications in Geology (Vou.7

MEASUREMENTS OF DENTITION

. ; __ No. 20028 No. 20040
Length, anterior sde of I’ to posteror side of M’,

measured along outer border of dental series ...... 301. mm. 327.
Length, anterior side of P, to posterior side of M3... 141.9
Length, anterior side of inferior canine to posterior

Sie sO tN i tecdeen, = 28 og, aie ree dear ee eae ne 250. 290.

Greatest width of palate between outer borders of

superior cheek-tooth series (measured between

outer borders of third molars) —............. exer ne 141.9 148.
Least transverse diameter of palate between superior

cheek-tooth series (measured between inner

borders of fourth premolars)... 222... 66. 56.
Length, anterior side of P* to posterior side of M*... 142.7 156.4
Length, anterior side of M' to posterior side of M*.... 124. 132.
I"; anteroposterior diameter 22-222 cess eeeccee ese seese eee ceee ee tee 17.8
I’, greatest transverse diameter ...........-.... ; 9.7
Superior canine, anteroposterior diameter | ................ 13.9 13.2
Pe anteroposterior name te ase ere ne enreereeee ree eee 18.8
Ri yoreavest) vranms verses Clare bets -eceese ers s:seteeeesae eeeees 11.
Pe anteroposterior «diamecer jcccceeesee..ceccereser sees eeeee eee 23.5 228.
Pe, ereatest tramsverse diameter ace: ecstee ce eee senses 25. 22.5
IME) ANIGETOPOSteTIOn iam CUCT eres: s-neeusnesaeterseatee senses veam 24.4 42,
Mi, greatest transverse diameter. .........—-....-----.-0.2------ jl. 33.6
M=, anteroposterior Giam eter eco scessec = cecree sconces 42.1 - 52.
M’, greatest transverse diameter across protocone.... 31.6 32.8
M’, greatest anteroposterior diameter .. 49.5 45.8
Me, greatest tramsverse diameter -..22.2 2 nceeeseeeee 31.4 27.2

Type of | Cope’s
C. hes- Texas No, 20028 No. 20040
ternus specimen§

Length, anterior side of P, to pos-

eeveioye FSEUG ey Kaye IY LA eee eee $164. 142. mm, 7162.2
J,, greatest transverse diameter al3. 17.9 19.
I., greatest transverse diameter ........ OF 20.4 18.8
1,, anteroposterior diameter of alveolus 12. 28.5 25:3
Inferior canine, greatest anteropos-

TCOLLOLe MATE GIy eeeeese sees eens al2. 16.1
P,, greatest anteroposterior diameter 27. Pile 21.9 27.5
P,, greatest transverse diameter ...... 12.9 13.4
M,, anteroposterior diameter -............. 42. 38. 28. 39.
M,, greatest transverse diameter ........ PAA 21.5
M., anteroposterior diameter —............. 52. 44, 38.4 46.
M., greatest transverse diameter ........ 22. 21.2
M,, greatest anteroposterior diameter 58. 56. 58.2 58.
M;, greatest transverse diameter across

Pon Hever(One MWooye! 2 eee eee aro eee 21.6 18.5

a, approximate.

* at base of crown.

+ M, not completely emerged.

+ From Cope’s figure of the specimen.

§ Cope, E. D., Geol. Surv. Tex., 3rd Ann. Rep. for 1891, pl. 21, figs. 3 and 4.

1913] Merriam: A Camel from Rancho La Brea aly

RELATION OF RANCHO LA BREA SPECIMENS TO PREVIOUSLY

DESCRIBED PLEISTOCENE FORMS FROM NORTH AMERICA

It is perhaps undesirable at this stage in the study of the
Rancho La Brea camels to attempt a final determination of their
relationships to all of the known North America forms, bnt the
broader outlines of the problem may be presented.

The Rancho Ja Brea specimens so far as known are clearly
distinguished from the American Pleistocene species referred to
the genera Eschatius and Camelus. They are separated from
both Camelus and Eschatius by their dental formula of 4, 4,7, 4.

In the mandible from Hay Springs referred by Wortman‘ to
the genus Camelus the formula is 3, 7, 3 ,z3; the inferior canine
is more or less incisiform, and is not separated from I, by a
marked diastema; and P, is caniniform.

The genus Hschatius is characterized by the most extreme
reduction known in the cheek-tooth dentition, the formula of

106

Fies. 10a and 10b. Camelops kansanus Leidy. Type specimen, adapted
from Leidy, natural size. Fig. 10a, anterior end of rostral region, lateral
view; fig. 10b, anterior end of rostral region, inferior view.

318 University of California Publications in Geology [Vou.7

the upper series being P1 M®, P®* is not represented, and P* is
reduced to a simple conical form not unlike the small P? of the
Rancho La Brea specimens.

The American Pleistocene forms with which the Rancho La
Brea specimens are most closely related are those included in
the species that have been referred to Camelops, Auchenia, and
Holomeniscus.

Comparison with Type Specimens of Camelops.—Leidy’s type
of Cameolps consisted of the anterior end of a premaxillary bone
with the root of the last upper incisor, and a small piece of the
maxillary, with the alveolus of the canine (figs. 10a and 10D).
Compared with this specimen, the anterior end of the rostral
region of the Rancho La Brea skulls shows httle to distinguish
it. The general proportions of the elements present and the
location of the teeth are nearly the same. The extension of
the maxillary forward around the anterior end of the anterior
palatine foramen noted in the Rancho La Brea specimens is much
as in the type of Camelops.

Comparison with the Type Specimen of Auchenia hesterna
Leidy.—The type specimen of Auchenia hesterna was discovered
by Dr. Lorenzo G. Yates in Livermore Valley, California, in a
eravel deposit which was presumed by Dr. Yates to represent an
old river channel. <A statement by Leidy, based upon the com-
munication of Professor EK. O. Hovey. to the effect that it was
found twenty-five miles inland from San Leandro, California,*
is erroneous, according to Dr. Yates.”

The type consists of a lower molar series and a single upper
molar. There is some uncertainty as to whether these teeth al!
represent the same individual. The fact that the relative stages
of wear are approximately what one might expect to find in the
same series is evidence in favor of the view that the lower teeth
are all from one animal. ; ;

The dentition of the Rancho La Brea specimens resembles
that of the type of Auchenia hesterna in the presence of a single

7 Wortman, J. L., Bull. Am. Mus. Nat. Hist., vol. 10, p. 133, 1898.

8 Leidy, J., Geol. Surv. Terr., vol. 1, Fossil Vertebrates, pp. 228, 229, 256,

1873.
® Yates, L. G., Proce. Acad. Nat. Sci., Philad., vol. 26, p. 18, 1874.

1913 | Merriam: A Camel from Rancho La Brea 319

lla

I1b

Figs. lla and 11b. Camelops hesternus (Leidy). Inferior cheek-tooth
series of type specimen, X 14. Fig. lla, oeclusal view; fig. 11b, lateral
view. (Adapted from Leidy.)

premolar, P,, with a wedge-shaped cross-section. The general
form and relative dimensions of this tooth are much the same
in the type of A. hesterna and in specimen 20040 from Rancho
La Brea. The nature of the posterior enamel fold of the crown
is similar in the two. In the type of A. hesterna (Leidy, pl. 37,
fig. 2) P, is represented with a distinet groove on the outer side
marking the division of the tooth into anterior and posterior
regions, each terminating inferiorly in a distinct root. In
Rancho La Brea specimen 20028 there is an exceedingly faint
separation of the two roots, and the inner face of the crown
may show a faint groove, marking this division; there is, how-
ever, no external groove as represented for A. hesterna. In

320 University of California Publications in Geology |Vou.7

Leidy’s figure 1 of the plate to which reference is made above
the identical P, represented in figure 2 seems to show almost no
external groove.

In the type of Auchenia hesterna, M, and M, are both very
considerably larger than in specimen 20028, and M, seems rela-
tively much larger, especially compared with M,. In specimen
20040 the dimensions of P, and M, are practically identical with
those in the type of A. hesterna. M, is only seven per cent
smaller, and M, eleven per cent smaller. The slight differences
between specimen 20040 and the type of A. hesterna seem to the
writer of less than specific value, and the Rancho La Brea form
may be considered as typifying that species. The differences
between nos. 20040 and 20028 are greater than between 20040
and the type of hesterna, but considering the close similarity in
form and dimensions of the skull, together with the evident
difference in age of the two individuals, the writer is not inclined
to believe the difference in tooth measurement as of specifie rank.
No. 20028 represents a much older animal than no. 20040. During
a considerable period in the life history of each individual P,
and M., increase in anteroposterior diameter of the crushing face
as the crowns wear down; while M, and 4,, with crowns narrow-
ing inferiorly much earlier than the other teeth, shorten the
anteroposterior diameter of the occlusal surface. There seems
also to be some individual variation in tooth dimensions, so that
age, with sex and individual variation, may produce rather large
differences in relative size of the teeth.

The upper molar of Auchenia hesterna figured by Leidy does
not differ greatly from M? of the Rancho La Brea form.

A California species deseribed by Leidy'!® as Auchenia califor-
nica previous to the publication of A. hesterna may be identical
with lesterna, and may therefore include the specimens here
deseribed. This can best be determined by a careful comparative
study of all skeletal material obtained, as A. californica was
based solely upon limb and arch bones of very large size. If we
give full value to the statement on the label accompanying the
type specimen of A. californica, to the effect that it came from
beneath the lavas at Table Mountain, it is probable that this

20 Leidy, J., Proe. Acad. Nat. Sci., Phila., 1870, p. 126.

1913 | Merriam: A Camel from Rancho La Brea a2

species is of Tertiary age, and presumably specifically if not
generically distinet from the Rancho La Brea form.

Comparison with the Forms referred to by Cope as Holo-
meniscus hesternus, H. sulcatus, WT. witikerianus, and H. macro-
cephalus.—A fine mandibular ramus from Bowie Bend, Austin
County, Texas, was considered by Cope'' to represent the same
species as the type of Leidy’s Auchenia hesterna. Cope’s speci-
men is undoubtedly near hesterna, and resembles it more closely
in the dimensions of M, and M, than does specimen no, 20028
from Rancho La Brea. The reference of this specimen to hes-
ferna by Cope on the basis of evidence then available seems
justified.

Compared with Cope’s Texas type of Holomeniscus hesternus
the specimens from Rancho La Brea show a slightly larger
mandible with more widely spreading incisors and a larger I,,.
As nearly as ean be determined, I, of the Rancho La Brea speci-
mens is much larger compared with I, than in the Texas form.
The dimensions of the cheek-teeth are closely similar in Cope’s
specimen and no. 20040 from Rancho La Brea, The Texas speci-
men and those from Rancho La Brea are evidently generically
identical. The characters separating them are doubtfully of
specific rank. The determination of the exact specific relation-
ship of these two forms may well await an examination of all
possible collections from Rancho La Brea, to determine the mits
of variability of the California form.

A specimen from Tequixquiae, Mexico, described by Cope’
is near the form from Texas

Holomeniscus sulcatus Cope from Texas is near the Rancho
La Brea species in many characters. The type of HZ. sulcatus is
an old individual with worn P, and M,, and measurements of the
dentition are very close to those of no. 20028 from Rancho La
3rea, in which the teeth give evidence of a similar stage of wear.
As has been suggested by Wortman, the pecuhar characters of
this species may be shown later to come within the limits of
individual or age variations of one of the previously deseribed
forms, like Camelops kansanus or C. hesterius.

11 Cope, E. D., Geol. Surv. Texas, 3rd Ann. Rep. for 1891, pp. 71 and 85.
12 Cope, E. D., Amer. Phil. Soe. Proc., vol. 22, p. 18, May 16, 1884.

3o2 University of California Publications in Geology |Vou.7

The Pleistocene species described by Cope as Auchenia
vitikeriana'’* and Holomeniscus macrocephalus'* are possibly
generically identical with the Rancho la Brea species, but are
specifically distinct. The form of the posterior lobe of M,
in H. macrocephalus is quite different from that of Camelops
hesternus.

SUMMARY

The Rancho La Brea form seen in specimens nos. 20040 and
20028 closely resembles as much as is known of the type specimen
of Camelops Leidy. Although no satisfactory generic deserip-
tion of Camelops was given by Leidy, it is probable that the
Rancho La Brea specimens represent the same generic group as
the type specimen. Rancho La Brea specimen no. 20040 is evi-
dently generically and spee¢ifically identical with Leidy’s type
of Auchenia hesterna. It is also generically identical with
Cope’s specimen identified as Holomeniscus hesternus, from
Texas. Cope’s type of Holomeniscus sulcatus is evidently in the
same generic group. Holomeniscus vitikerianus presumably
belongs in the same genus with the species just mentioned, and
possibly also H. macrocephalus.

As shown by Wortman the separation of the North American
Pleistocene camels from Auchenia is justified on the basis of
differences in the form of the inferior molars, and the characters
given by Cope to Holomeniscus are not distinctive. For the
present at least the writer adopts the suggestion of Wortman that
the name Camelops should be used for the group of species
represented by C. kansanus and C. hesternus, since it is the
earliest designation applied.

The group of camels referred to Camelops, and represented
by specimens nos. 20040 and 20028 from Rancho La Brea, is
much nearer to Auchenia than to Camelus, but is nevertheless
distinct from the typieal Auchenia. It is separated from
Camelus by the premolar formula of ?, instead of 3, relatively
small size of P*, broad contact of the nasals and premaxillaries,

13 Cope, E. D., Bull. U. 8. Geol. and Geog. Surv. Terr., vol. 4, p. 380,
1878.

14 Cope, E. D., Geol. Sury. Texas, 3rd Ann. Rep. for 1891, p. 85 and pl.
23, figs? 5 and 5a.

1913 | Merriam: A Camel from Rancho La Brea BOB

presence of well-defined maxillary fossae, relatively great anterior
extension of the zygomatic process of the squamosal, absence of
a lateral bordering wall on the glenoid fossa, and the higher
mandible which tapers more gradually anteriorly.

The Camelops group as here comprised resembles Auchenia
in the general form of the skull and especially of the mandible,
the relation of the nasals and premaxillaries, relatively great
anterior extension of the zygomatic process of the squamosal,
form of the glenoid fossa, and in premolar formula. The group
differs from Auchenia in the form of the frontal region. nar-
rower nasals, presence of large maxillary fossae. form of the
mastoid process, more nearly quadrate form of P*, more distinctly
wedge-shaped cross-section of P,, absence of folds on medial side
of P,, less marked development of styles and ribs on outer side
of upper molars and inner side of lower molars, and absence of
strongly marked anteroexterna] styles in M.,, and M,.

Although a definite statement as to the affinities of Camelops
would be premature if presented in advance of a study of the
entire skeleton, it seems desirable to eall attention to the resem-
blance in characters of skull and dentition in the Rancho La Brea
form to those of Pliauchenia (Megatylopus) of Matthew and
Cook."®

15 Matthew, W. D., and Cook, H. J., Bull. Amer. Mus. Nat. Hist., vol.
26, pp. 396-401, 1909.

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Issued June 12, 1913

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. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by

. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. Schaller
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. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. Evan
. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallmon
. Euceratherium, a New Ungulate from the Quaternary Caves of California, by

. A New Marine Reptile from the Triassic of California, by John C. Merriam..........
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. Geological Section of the Coast Ranges North of the Bay of San Francis

. Areas of the California Neocene, by Vance C. Osmont.....--------+---snsen-snnsem
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Psychology. Zoology, and Memoirs.

7”

Volumes 1 (pp. 435), II (pp. 450), III (pp. 475), IV (pp. 462), V- (pp. 448),
completed. Volumes VI and VII (in progress). |

Cited as Univ. Calif. Publ. Bull. Dept. Geol. .
Volume 1, 1893-1896, 435 pp., with 18 plates, price-t....2-----cstceeese-cceregeeeneener
Volume 2, 1896-1902, 450 pp., with 17 plates and 1 map, price..........-...0--

A list of the titles in volumes 1 and 2 will be sent upon request.

VOLUME 2.

. The Quarternary of Southern California, by Oscar H. Hershey -0...-2---cccececccececceceeeoee
. Colemanite from Southern California, by Arthur 8. Hakle.....-.c--.22-cceccceceseeeeopeeeee

Andrew G.- Lawson 2..ccccsscl oi c-dyensdeecp ce esecn acne toecbatnces dave satacs os eaeene ta eae
The Igneous. Rocks near Pajaro, ‘by John A” Reid sc: tes ies otc cece ee

Andrew GC, Lawson --cc.-n-scesbetseciceoe Ses cescetettes ens once se nebn oe pe ease eee a

. Palacheite, by Arthur S: Bakle:....:c22::.. Mack ce
. Two New Species of Fessil Turtles from Oregon, by O. P. Hay.
. A New Tortoise from the Auriferous Gravels of California, by W. J. Sinclair.

Nos, 10 ando il in one? coVer iic.2<--cc)---.2- Sse k Sc eee ae

. New Ichthyosauria from the Upper Triassie of California, by John C. Merriam...
. Spodumene from San Diego County, California, by Waldemar T. Schaller...............-
. The Pliocene and Quaternary Canidae of the Great Valley of California, by

John C. Merriam ......: Boiaenene cnvedboede ce Javed p tbe cate sns ce) Soseateee ten sot ana enna aa) Naess an ner
The Geomorphogeny of the Upper Kern Basin, by Andrew C. Lawson........-....--.-.
A Note on the Fauna of the Lower Miocene in California, by John C. Merriam......
The Orbicular Gabbro at Dehesa, San Diego County, California, by Andrew C.

ASW BOT heen nase ee ee once See nae eon er ee ee RN en Sie TN ce =

William J. Sinclair and EH. L. Furlong ........-------2c----ccec--cesc-ssteeceseeconneceetanennenrensnseneenenerane

VOLUME 4.

CG... “Merriam 222 ee a eee
co,
VAC Osmotic naa ne ce ne a ee

New or Imperfectly Known Rodents and Ungulates from the John Day Series,

William J. Simelair —....-----..-.-e-eeececcececteeeoececeneennenensenacensececenenecenannnes sennseeeenencnnees
New Mammalia from the Quarternary Caves of California, by William J.

IMG dle aes lee BoA ro: ceecerencentee ae secceeeeneesneraneccnenanscennennnscnteteatcansstasenauscanectnasnaasts Sean aaaea

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 15, pp. 325-334 Issued June 12, 1913

THE PETROGRAPHIC DESIGNATION OF
ALLUVIAL FAN FORMATIONS

ANDREW C. LAWSON

CONTENTS

PAGE
Wisemoty the Merm) (Breccia. 2.--:.222cecceceeeecceecteec sees eeeose ee 8 AB BON ON AO 325
Alluvial Fans are Formations of Vast Extent .......220.22.22.2::21::c0000 eee 326
Wiserotethe erm Conglomerate -2.......-2..::ccccecssccresesseccecsectescecoccsecseentensssoeea=se 327
Ancient Alluvial Fan at Battle Mountain, Nevada -220...00..0000.00..0.2.-2.22----- 328
ARGU AL, LIMO HARA VE ah oXo}S{=X6 Leer ee ay eee 329
I batraenry ey nico ash Co Led cNey 1 NES eho eee cp SE 330
Avie tiesnof Ham olOMer at ee. o.-c2ec ce 22d ea cescccsceeceneceeetece cscs ceecececeeeceeeceeeeseceneeeees 33
Geological Significance of the Battle Mountain Fanglomerate ............. 332
Searcity of Fanglomerate among the Rocks of the Past... 333

Use of the Term ‘Breccia.’-—The following quotations refer-
ring to the significance of the word ‘‘breccia’’ are taken from
the current edition of a well-known American text-book of
geology:

‘*Voleanie agglomerate, or breccia, is a mass of angular blocks of lava,
with which may be mingled fragments of sedimentary rocks, which the
volcano has torn from the sides of its chimney. . . . Ordinarily the breccia
is found only near the vent, etc.’’

“‘Breccia is a rock composed of angular fragments cemented hy
deposition of material, commonly CaCO,, in the interstices. The frag-
ments may be any kind of rock. Breccia is also found in zones of
fracturing and shattering of the rocks along fault-planes and is then
called fault-breccia.’’

‘*Coral conglomerate or breccia is a cemented mass of coral pebbles or
angular pieces or is made up of fragments of an older coral rock.’’

326 University of California Publications in Geology [Vou.7

‘*Great masses of angular blocks of all sizes accumulate at the foot

of cliffs and on mountain slopes as talus, which shows an imperfect
division into layers and is slowly but continually creeping downward.
By the deposition of some cementing material (usually CaCO,) in the
interstices of the talus the blocks may be bound into a solid mass, called
breccia, of which the peculiarity is that the fragments composing it are
angular, not rounded.’’

““TIn-a eave it frequently happens that angular fragments fall from
the roof and are cemented into breccia by deposits of stalagmite.’’

The diversity of use to which the word breccia is put by this
author is not peculiar to his text. It is equally well exemplified
in other books, some authors emphasizing one use of the word
and some another, but nearly all using it in more than one sense.
The term is, indeed, applied to other things than are indicated
by the foregoing quotations. For example, the aggregate of
blocks of rock imbedded in lava due to the breaking up of a
lava crust while the flow beneath is still molten, is commonly
ealled a breccia; and certain gangues of ore that have been broken
and recemented, such as the zine ores of the Joplin district, are
similarly designated.

It is evident from this current usage that breccia is a generic
term applicable to a rock of any kind which is composed of an
aggregate of angular fragments, the origin of the fragments and
their mode of aggregation being ignored except by the intro-
duction of a supplementary word or phrase. The usefulness of
the term inheres in that comprehensiveness which is character-
istic of the terminology of an immature science.

Alluvial Fans are Formations of Vast Extent—In arid
regions of bold relief there are vast deposits of ‘‘wash’’ or rock
detritus in the form of confluent or interdigitating alluvial fans,
which are among the most important continental formations now
in process of accumulation. Probably more than half of the area
of the state of Nevada is occupied by such deposits and in large
parts of Utah, New Mexico, Arizona, California, and Mexico, they
are the most extensive formations encountered by the geologist.
These alluvial fans consist of rock detritus which grades in size
from coarse blocks near the mountains to fine silt in the playas
or river bottoms. The assortment of materials is effected by the
diminishing capacity and carrying power of running water in

1913] Lawson: Designation of Alluwal Fan Formations 327

its descent from the mountains to the valley, and the result is
in general a fairly regular gradation; although large blocks are
of common occurrence far down the slopes of the fans, due to
exceptional rushes of water from the mountain canons.

The material in general is but little rounded by attrition,
being prevailingly angular or at best sub-angular. There may,
however, be admixtures of well water-worn pebbles derived from
old conglomerates in the mountains whence all the detritus comes.
Some of the larger blocks may have a rounded or boulder-like
shape, but this is due to exfoliation rather than attrition.

Use of the Term Conglomerate.—Such alluvial fan deposits
when they become cemerited, and so become coherent rocks, may
in accordance with current usage be ealled breccia. But this
word, as I have pointed out, is so overburdened with meanings
that it has no particular connotation suggestive of what kind of
rock we are speaking of, other than that it is composed of
angular fragments; and an aggregate of angular fragments may
originate in several different ways. The insufficiency of the term
breccia as a designation for the kind of rock here considered is
well illustrated in the use of the term Gila Conglomerate for the
Quaternary alluvial fan deposits of Arizona. This term was
first used for this formation by Gilbert? in 1873, and has more
recently been adopted by Ransome.? But Ransome’s descrip-
tion of the formation makes it clear that it is different from the
rocks to which the term conglomerate is usually and properly
applied. Indeed, he says that ‘‘the formation might appropri-
ately be termed a breccia.’’ Geologic usage and formal defini-
tions are fairly consistent in applying the term conglomerate to
an aggregate of well rounded water worn pebbles, and there can
be little doubt of the advantage of adhering to this practice.

It is the purpose of this paper to raise the question from a
general point of view of the advantage or disadvantage of con-
tinuing the use of the term conglomerate for formations having
an origin geologically distinctive from that of ordinary con-
glomerate, and physical characteristics which are those of a
breccia; (2) to call attention to the insufficiency for geological

i Wheeler Survey, vol. IL, 1875, p. 540.
2U.S. G.S. Prof. Paper no. 12, 1903, p. 47. U.S. G.S., folio 111, p. 5.

328 University of California Publications in Geology [Vou.7

purposes of the term breccia as applied to alluvial fan deposits
owing to its comprehensive or generic meaning; and (3) to
suggest a petrographical name for such deposits.

Ancient Alluvial Fan at Battie Mountain, Nevada—My
attention was drawn particularly to the question of a suitable
designation for alluvial fan deposits in the course of a recent
visit to Battle Mountain, Nevada. The rocks of Battle Mountain
consist chiefly of quartzite, shale and limestone of Paleozoic age.*
These are traversed by dykes of igneous rock prevailingly of
rhyolitie type, some of these dykes having an abundance of large
phenocrysts of quartz. The rock of the dvkes is in some eases
quite fresh but in other cases it is decomposed and is then
charged with copper ores to such an extent as to have stimulated
much prospecting. In the northeastern portion of the mountain
with which I beeame particularly familiar the Palaeozoic strata
dip prevailingly to the eastward, but in some localities westerly
dips were also observed. According to the report on the Geology
of the 40th Parallel* the prevailing dip of the mountain, pre-
sumably farther west, is westward, thus indicating that the
general structure is anticlinal.

Resting unconformably on the upturned edges of these strata,
and occurring chiefly as a mesa-like cap on various hilltops, is
a later formation composed of angular fragments of the under-
lving rocks, but so thoroughly silicified and cemented that it is
one of the hardest and most resistant formations of the district.
Ilere and there in the midst of the angular fragments there may
be found well water worn pebbles which have probably been
derived from some earlier conglomerate. The fragments range
in size up to several inches in diameter, and it is evident that
any sorting action to which they may have been subjected in the
process of accumulation has been an inefficient one. There are
many holes or cavernous spaces in the rock which have the same
range of dimension as have the fragments which make up the
rock. These spaces were originally probably occupied by frag-
ments of Hmestone which have been dissolved out by meteoric

’ Hague and Emmons (Geology of the 40th Parallel, vol. II, p. 666, et

seq.) refer the limestone to the upper coal measures and the quartzite to the
Weber quartzite on the basis of fossils found in the limestone.

4 Loc. cit.

:
H
:

1913] Lawson: Designation of Alluvial Fan Formations 329

waters. Except for the fact that it is thoroughly cemented and
indurated, the rock is very similar to the detritus which flanks
the margins of the mountain in the form of alluvial fans. There
ean be little doubt but that the formation is the remnant of
an alluvial fan deposit spread over the region in the remote
past. The antiquity of the deposit can be indicated only in a
general way. The induration itself distinguishes the formation
from any of the Quaternary deposits which the writer has
observed in many parts of Nevada. Its position as a cap on the
residual hills of the degraded mountain mass, perhaps a thousand
feet above the floors of the adjacent valleys, indicates that it
antedates the uplift which inaugurated the present erosional
eyele. It also antedates the invasion of the country by the
igneous rocks, since some of the copper bearing dykes cut the
deposit. Moreover, it is traversed by several of the numerous
faults which have dislocated the formations of Battle Mountain,
since it is found at various sharply contrasted levels. This
faulting probably belongs to an older period of disturbance
which affected the region anterior to the degradation which in
turn preceded the late Tertiary faulting concerned in the up-
tilting of the Basin Ranges. Relying upon this interpretation
of the age of the faulting, which of course requires the con-
firmation of more extended field work, this interesting formation
appears to have been deposited between the close of the Paleozoic
and the period of deformation which occurred at the close of
the Jurassic. Leaving the definite determination of its age,
however, an open question, the formation is of peculiar interest
as revealing a physiographic condition analogous to the present
which prevailed in this part of Nevada in the remote past.’
Term Fanglomerate Proposed.—For the discussion of this
formation a petrographieal designation is necessary. I hesitate
to call the rock a conglomerate because that does violence to
our current definition of this term and suggests an erroneous
conception of the mode of deposit and the climatic conditions
which determined that mode. I am equally loath to refer to it
as a breccia because that term suggests nothing as to its genesis,
nor does it as a purely descriptive term differentiate the rock
from others similarly designated. To fill the gap in our nomen-

330 University of California Publications in Geology |Vou.7

clature I propose that this and similar rocks be known as
fanglomerate. The word is a hybrid and objection will doubtless
be made to it on this score. It is, however, a deseriptive term
with specific connotation as to both the character of the rock and
its mode of formation. My purpose in suggesting the term is
not so much to amplify the terminology of petrography as to
emphasize the geological significance of a class of rocks which
have received but ttle attention.

Limitations of the Term.—In defining the term I must first
make clear that it is not intended to include the finer sediments
on the lower flanks of alluvial fans, but only the coarser deposits
in the upper part of the embankment. In setting limits of
texture or size of grain within which the term fanglomerate shall
apply we encountered the same difficulty as in the case of con-
glomerate. When the constituent units of a conglomerate are
very large the aggregation is often referred to as a ‘‘boulder
bed’’; and when they become small the rock passes insensibly
into a sandstone. Barrell in a recent paper’ places the lower
limit of the diameter of pebbles in a conglomerate at 5mm.,
but states that common usage places it at about 2mm. The
transitional condition may be, and usually is, designated by
various descriptive phrases, there being no hard and fast line
between common ccnglomerate and common sandstone.

As to the coarseness of texture of fanglomerate there appears
to be no convenient upper limit other than that set by nature.
In many alluvial fans the censtituent blocks are of extraordinary
size near the apex, and sporadic blocks several feet in diameter
are by no means uncommon far down the slope where the average
size of the fragments may be less than an inch. Whether the
large blocks be aggregated, or whether they occur more or less
isolated in the midst of finer material, they form an integral
part of the deposit and are of course included in the term
fanglomerate. It is evident from this that some of the most
interesting facies of fanglomerate cannot be illustrated by speci-
mens, and that students will be able to familiarize themselves
with them only by field examination.

5 Bull. G. 8. A., vol. 23, p. 442, 1912.

1913] Lawson: Designation of Alluvial Fan Formations gol

It is to be noted here that cliff talus is to be discriminated
from alluvial fan accumulations. A typical talus or scree,
whether cemented cr not should not be included under the term
used to designate fan deposits. The latter are transported and
laid down by running water and are therefore sedimentary. The
former accumulate under the direct action of gravity and are
not sedimentary in their mode of deposition. Slight admixtures
of talus may enter into the composition of certain fans on their
upper margins, but this fact will not ordinarily affect the dis-
crimination. Should it be found expedient to refer to talus
formations by a specific petrographical designation, as it well
may be in a complete aceount of detrital rocks, it is desirable
that the term should be distinet from that apphed to fan deposits.

Toward its lower limit of coarseness fanglomerate grades into
what is ordinarily termed arkose. This arkose is far from uni-
form in size of grain, however, and if we set arbitrarily 5 mm.
as the maximum diameter of fragments in arkose, pieces of this
and smaller sizes will be found intimately mixed with much finer
material. The same defect in sorting which characterizes the
fanglomerate is also exemplified in the arkose.

On the lower slopes of the alluvial fans the arkose passes into
silt and mud which also oceupy the bottoms of the plavas and
river flood plains.

In these alluvial embankments, which form such notable con-
tinental deposits of sedimentary origin, we have thus three rock
types, viz: fanglomerate, arkose and silt. The first two of these
may be easily discriminated from marine deposits, and it seems
probable that microscopic methods of study will supply the
eriteria for distinguishing the third, in cases where this cannot
be done on the basis of field associations.

Varieties of Fanglomerate.—Fanglomerates may vary greatly
in the character of the materials of which they are composed.
The most typical embankments are composed of fragments of
variously indurated sedimentary rocks of mountain ranges under-
going rapid degradation in an arid climate. Some of these ranges
may, however, be made up chiefly of igneous rocks, either
plutonic or voleanic and the composition of the flanking fan-
glomerate will correspond to the character of the detritus sup-

Baz University of California Publications in Geology |Vou.7

plied. When the range is composed chiefly of voleanic rocks
the fanglomerate may resemble an agglomerate. These distine-
tions are, however, matters for petrographical description rather
than for a special varietal nomenclature.

Other varieties are based upon the degree of induration and
the nature of the cementing material. The fanglomerates now
in process of accumulation in Nevada, Utah, and California are
usually incoherent or but feebly cemented; but in parts of
Arizona, New Mexico and over a large part of Mexico, the
embankments of fanglomerate are to a varving depth strongly
cemented by carbonate of lime. The process of cementation is
now in progress on a vast scale and proceeds as fast as the
detritus accumulates. This cemented detritus forms one of the
numerous kinds of deposits called in Spanish countries caliche.
This variety of fanglomerate has an additional geological interest
in that it constitutes a continental deposit at the local base level
of arid erosion, which is in a large measure resistant to erosion,
when, in the course of time, the base level is lowered. It is little
affected by structural planes, such as joints and bedding, and is
thus not so susceptible to disintegration as the rocks from which
it is derived. Neither is it susceptible to waste by aeolian
ablation. The cementing carbonate of lime though occupying
the spaces between the rock fragments is practically svngenetic
with their accumulation.

A genetically distinct process of cementation is similar to that
which indurates ordinary sedimentary rocks and which is
apparently conditioned by the burial of the strata by later
deposits. In this way sands are converted into hard sandstones
and quartzite. Similarly the incoherent materials of an alluvial
fan may in the course of time be so strongly cemented that
when broken by a blow the fracture will traverse the constituent
fragments rather than pass around them. This is the case with
the fanglomerate of Battle Mountain.

Geological Significance of the Battle Mountain Fanglomerate.
Apart from its interest as a type of sedimentary rock the fan-
elomerate of Battle Mountain is significant of the existence of
conditions in the far past similar to those which prevail in the
Great Basin today. Those conditions are bold relief and aridity.

1913] Lawson: Designation of AUuvial Fan Formations ooo

But bold relief is the immediate result of acute diastrophism
and this fact must be taken into consideration in the attempt to
determine the geological age of the formation. Such disturb-
ances occurred at the close of the Carboniferous. and at the close
of the Jurassic. The correlatives of the formation doubtless
occur in other parts of Nevada where post-Jurassic granite
abounds and if in such localities the formation should be found
to be devoid of granite fragments a presumption weuld be
established in favor of a pre-Jurassic age. Whether it be pre-
Triassic or post-Triassic ean probably be determined by its
relations to the Triassic rocks to the west of Battle Mountain.

The tracing out of the distribution of this fanglomerate will
be an interesting contribution to the geology of Nevada since it
affords a definite datum of a peculiar kind from which the
geological history of the region may be reckoned. It is not only
a positive mark in the geological time scale, but a mark which
may be interpreted in terms of climate, diastrophism and
physiography.

Scarcity of Fanglomerate among the Rocks of the Past—The
abundance of fanglomerate now in process of accumulation in
the arid regions of North America at the present time suggests
that similar rocks should be found among the continental deposits
of the past more commonly than the observations recorded in
geological literature would indicate. It is posible that such rocks
have been described under the name of ‘‘breecia,’’ and that this
term has been inadequate to discriminate them from other types
of fragmental rocks, so that their significance has been over-
looked. This may be the case, for example, with the so-called
‘‘hreecias’’? and ‘‘breeciated conglomerates’’ of the Newark
system. But making due allowance for this possibility it is
remarkable that there are so few, if any, descriptions of conti-
nental formations that correspond with the alluvial fan deposits
of Pleistocene and Recent age so abundant in the western part
of the continent. If such rocks existed they could hardly fail of
recognition and description; and the inference seems warranted
that, in those portions of the continent with which geologists are
particularly familiar, fanglomerate does not occur. If this be so
then one or the other or both of the conditions which determine

334 University of California Publications in Geology [Vou.7

the accumulation of alluvial fans must have been lacking. The
failure to recognize alluvial fan formations as constituent ele-
ments of the stratigraphic column may, therefore, be explained
by the supposition that the combination of bold relief and aridity
was not common in the geological past. Perhaps the inference
may be earried so far as to warrant the belief that this combina-
tion of conditions failed entirely except in those periods in which
fanglomerate is represented in stratigraphy, such as the uncer-
tainly defined divisions of the Mesozoic of Nevada here described,
and possibly the Newark Triassic. It may be urged that alluvial
fan formations may have existed and been swept away either by
peneplaination or by marine transgression. But it may be
pointed out that the increasing recognition of continental for-
mations indicates that they are not particularly prone to destruc-
tion by transgressing seas; and that, while peneplaination would
bring to an end the formation of coarse alluvial fans by doing
away with bold relief, it would only be in extreme cases of perfect
peneplaination, due to continental emergence through a succes-
sion of geological periods, that the earlier formed alluvial material
would be swept away. In those portions of the continent in
which there is an approximately complete stratigraphic record
of any large portion of geological time, and in the stratigraphy
of which there is no representation of fanglomerate, it may be
safely inferred that, for the time in question, bold relief and
aridity were never coexistent conditions. It may further be
concluded that the period of time extending through the Quater-
nary to the present is exceptional in geological history in respect
to the coexistence of these two conditions over a large portion
of the continent.

Transmitted March 19, 1913.

: GEO Loy =

Issued September 19, 1913

MOHAVE ‘MIOCENE OF
| ae _ CALIFORNIA.

BY
JOHN C. MERRIAM

UNIVERSITY OF CALIFORNIA PRESS :
BERKELEY :

Nore.—The Unvenig of California
eations of learned societies and institutions, universities

all the publications of the University will be sent upon "Fequest
publications and other information, address the Manager of the
California, U. S. A. All matter sent in exchange should oe adiirecteds
Department, University Library, Berkeley, cae. U.S. A.

Otto HaRRASSOWITZ R. FRIEDLAENDER &
LEIPZIG : BERLIN

Agent for the series in American Arch- Agent for the series in Ameri
aeology and Ethnology, Classical Philology, aeology and Ethnology, Botany,
Education, Modern Philology, Philosophy, Mathematies, Pathology,
Psychology. ° Zoology, and Memoirs.

Geology. AnprEew C. Lawson-and Joun C. Merriam, Bditors. Price per volu
Volumes 1 (pp. 435), II (pp. 450), III (pp. 475), IV (pp. 462), V (Pp. 448)
completed. Volumes VI and VII (in progress).

Cited as Univ. Calif. Publ. Bull. Dept. Geol.
‘ Volume 1, 1893-1896, 435 pp., with 18 plates, price......
Volume 2, 1896-1902, 450 pp., with 17 plates and 1 map, prlve

A list of the titles in volumes 1 and 2 will be sent upon request.

VOLUME 3.

. The Quarternary of Southern California, by Oscar H. Hershey
- Colemanite from Southern California, by Arthur S. Hakle ar.
. The Eparchaean Interval. A Criticism of the use of the term Algonear i
Andrew. (Cl dawson, io. ecsbecese 20 ocee ce teen at pants goes a ee eee a eee enmes paee ere
. Triassic Ichthyopterygia from California and Nevada, by John C. pee
A Contribution to the Petrography of the John Day Basin, by Frank C. Calkin
The Igneous Rocks near Pajaro, by John Az Reid.......-....-------ceccsseceseeonneeecrnaeeee
. Minerals from Leona Heights, Alameda Co., California, by Waldemar T. ‘Schall
Plumasite, an Oligoclase-Corundum Rock, near Spanish Peak, Caligouiy
Amdreyy -C.; Lrawsom) 32.220 aa a ra cc ces
9. Palacheite, by “ArthusjS, \Malkle seo... ce oo oe nearer anata ee ee
10. Two New Species of Fessil Turtles from Oregon, by O. P. Hay. Be cas
11. A New Tortoise from the Auriferous “Gravels of California, ee Ww. i Sinclair.
INos.40, and) 11m onercover i.e. sce. asec 2. aen ee nase eee tee ee
12. New Ichthyosauria from the Upper ee of California, oa Tei C. Merriam..
18. Spodumene from San Diego County, California, by Waldemar T. Schallerzsececs
14, The Pliocene and Quaternary Canidae of the Great Valley of ee uci
; Solu CeMlorriguyea wesc ae a eae ee ee re
15. The Geomorphogeny of the Upper Kern Basin, by Andrew C. Law:
16. A Note on the Fauna of the Lower Miocene in California, by John C, Merria . 05¢
17. The Orbicular Gabbro at Dehesa, San Diego County, California, by SST Cc.
TU WSOD, | foebadcenRcwcecnessndecnde-seesceeenseden ante neet bial pone <ceneee pos teee EBzE Rc peat oe Se eS ee ee
18. A New Cestraciont Spine from the Lower Triassic of Idaho, by Herbert M. E ns
19. A Fossil Egg from Arizona, by Wm. Conger Morgan and Marion Clover Tallm
20. Euceratherium, a New Ungulate from the Quaternary Caves of California
William J. Sinclair and E. L. Dyed Loy Ye Pilea ae eee ee A ere peat ac ete oe cor
21. A New Marine Reptile from the Triassic of California, by John CG Merriam..
22. The River Terraces of the Orleans Basin, California, by Oscar H. Hershey...

ONAN wry

VOLUME 4.7 is %
The Geology of the Upper Region of the Main Walker River,
Us) 16 see Ee A Pe em Re Prien eae ne enc S-eeecoreacr
A Primitive Ichthyosaurian Limb from the Middle Triassic of Nevada,
Gi. Mierriam 20 ae ee a nee nee pra

. Geological Section of the Coast Ranges North of the Bay of San er

. Arcas of the California Neocene, by Vance C. Osmont...
. Contribution to the Palaeontology of the Martinez Group, | b
. New or Imperfectly Known Rodents and Ungulates from the
William J. Sinclair «...--...-..-.-------:cecccecesseceesseceeecnensnercecoeeneanines
New Mammalia from the Quarternary Caves of California, :
Preptoceras, a New Ungulate from we Pane Cave, California,

COM Ook w pp

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 16, pp. 335-339 Issued September 19, 1913

A PECULIAR HORN OR ANTLER FROM THE
MOHAVE MIOCENE OF
CALIFORNIA

BY
JOHN C. MERRIAM

In a collection of mammalian remains from Miocene beds
in the Mohave Desert recently obtained by H. S. Mourning and
J. P. Buwalda, there is a horn or antler of peculiar type, unlike
any form known to the writer. This specimen is deseribed in
advance of a discussion of the whole fauna, in the hope that
a fuller expression of opinion may be obtained through the
discussion.

The specimen consists of a single fragmentary horn or antler
(no. 20052), which had been considerably weathered. It was
found at the University of California collecting loeality, no. 2057,
in the Mohave Miocene north of Barstow, California. From
earlier studies the fauna in the beds of this region has been con-
sidered as upper Miocene.t| Much larger collections than those
originally available are now at hand for study, and it is possible
that in this material more than one faunal zone may be repre-
sented, but the largest part of the Mohave Beds seems quite
certainly to represent an upper phase of the Miocene.

The portion of the horn or antler represented in specimen
20052 consists of a part of the beam, which divides into tivo
nearly equal branches diverging almost horizontally. Upon the
nearly even superior surface of the branches are a considerable
number of small spikes or papillae. Of the two branches, one

1 Merriain, J. C., Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 169, 1911.

336 Unversity of California Publications in Geology [Vou.7

Figs. 1, 2, and 3. Merycodus coronatus, n.sp. No. 20052, natural size.
Mohave Beds, Mohave Desert, California. Fig. 1, outer side of horn;
fig. 2, superior aspect of horn; fig. 3, medial side of horn.

1913] Merriam: A Peculiar Horn or Antler 337

is projected approximately in the plane of the flattened beam.
The other branch curves rather sharply away from this plane.
(See fig. 2). The branch bending away from the plane of the
beam is the smaller. A number of the superior spikes or papillae
bend out at a low angle from the convex side of the curve formed
by the two branches. It seems probable that the plane of the
beam was anteroposterior rather than transverse to the skull,
and that the papillae on the convex side of the bow are on the
outer or lateral, rather than on the inner side of the horn. If
the smaller of these two horizontal branches is the anterior, this
is the right horn.

The spikes or papillae on the upper side of the horn are in
two rows. There are six on the concave side, and four on the
convex side. The inner six are arranged in three pairs. Of the
outer four there is a single large spike opposite the posterior
inner pair and a similar one opposite the space between the
anterior and middle inner pairs, and a pair of papillae arising
from a common base opposite the middle inner pair. The inner
papillae are nearly erect excepting the most anterior one. The
papillae on the outer side are directed outward at a low angle.

Judging from the single specimen available, the anterior
branches of the right and left horns of this animal curved in
toward each other over the face, the other branch extended back-
ward and slightly inward, making a crown-lke or horseshoe-like
structure above the head. One row of the small spikes or
papillae was directed upward, and the other row was directed
outward around the margin of the crown.

Specimen 20052 most nearly resembles the horn or antler of
Merycodus, which it also approaches in size, and to some extent
in the texture of the horn. It differs from Merycodus in the
form of branching, and in the presence of the double row of
superior spikes. The texture of the surface of specimen 20052
differs somewhat from that of any of the numerous Merycodus
horns available from the Mohave Miocene. In no. 20052 the
surface is marked by numerous wavy reticulating lines or ridges,
which are not matched exactly on any available Merycodus speci-
men. It is possible that the contrast is due in part to condition
of weathering, but it seems partly due to difference in structure.

338 University of California Publications in Geology [Vou.7

The peculiarity of specimen 20052 may be accounted for on
the assumption that it is a ‘‘sport’’ or ‘‘monstrosity’’ of Mery-
codus necatus, a common form in the Mohave region. A large

Fig. 4. Merycodus necatus Leidy. Outer side of horn. No. 19832, x 4.
Mohave Beds, Mohave Desert, California.

number of Merycodus horns have been found in the Mohave Beds,
but on no other specimen has there been noted any suggestion
of the form seen in no. 20052, so that there was no common
tendency to develop this type of horn.

Specimen 20052 represents a type distinet from the other
available specimens of the Mohave fauna and, so far as the writer
is aware, it is the only known specimen. This may possibly be
urged against the view that it is an undescribed form, and not
a variation or a sport of a known Merycodus species. In this
connection it should be noted that the Mohave fauna is as yet
very imperfectly known, and that a considerable number of the
most important elements in the fauna have been represented by
single fragmentary specimens. For a considerable time the
oreodont group was known from the Mohave region only by a
fragment of a lower jaw with two imperfect teeth, this being
the only oreodont found in an area including all of California
and nearly all of Nevada.

1913] Merriam: A Peculiar Horn or Antler 339

If the peculiar horn here described represents a type hereto-
fore unknown, it would appear to be a form nearly related to
Merycodus necatus, the common Mohave species. (See fig. 4).
Merycodus necatus is characterized by the possession of a short
horn with a short, wide, flattened beam, from the broad summit
of which two nearly equal branches arise. The form seen in
no. 20052 would be produced by flaring the branches, bending
them toward the branches of the opposite horn, and developing
the superior spikes or papillae.

While the writer is not inclined to consider the specimen
seen in no. 20052 as certainly representing a new type of horn
or antler, or a previously undescribed animal, it seems desirable
to give a specific designation to this type, which may be known
as Merycodus coronatus. While the form of horn or antler seen
here suggests various kinds of antlers of the modern Cervidae,
there is no evidence to indicate that this Miocene animal repre-
sents anything more than a foreshadowing of a modern type.

Transmitted June 28, 1918.

GEOLOGY
B > Tasted September 19, 1913

THROTHERIUM AND MEGALONYX

é =>.) FROM THE

ISTOCENE OF SOUTHERN CALIFORNIA

a, See ee heh
CHESTER STOCK

~ OCT20 1913

, } wy
National Museu

UNIVERSITY OF CALIFORNIA PRESS
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. The Quarternary of Southern California, by Oscar H. Hershey ...............-.-- :

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. The Eparchaean Interval. A Criticism of the use of the term Algonkian, by
Andrew ©. Suawson ~....-2020> 5.3 ee ee ee mes

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New Mammalia from the Quarternary Caves of California, by William J.
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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 17, pp. 341-358 Issued September 19, 1913

NOTHROTHERIUM AND MEGALONYX

FROM THE

PLEISTOCENE OF SOUTHERN CALIFORNIA

CHESTER STOCK

CONTENTS

PAGE

Mena t.0 DUC G1 ON 2 - eee sSes2ee 232202 i8yseiceteescensscsbeeeyensetaccecce.tsscecescotes-vebescoes-otsatecesseseseceeaeton 341
INothnothenmm sera ciilicepss Wy SP. sescescceccetee een -2ccccseceneeeecceeeceeceane-eneceneee-s-a120 342
MDiaonostic Characters Ol SPCClES! e:cceceecec-escesececeececnnseccceccecceecresdaseenesseee 343

GSU WUUL, eh hea ie ee a ea oe eed 343
TEEN Ae ROY Baer rp et ee 349
Relation to Nothrotherium shastense .................-...2.---------:se-eeeeeeeeeoeoes 350
Nothrotheri uml?) haspia << et ees ee tee ir ee BON ead 350
IMfecallomiyxs(CalnhOrmuCus) We Sp)e.qceccsscccseteeescvesesescscee sce esezececccencee2 oe eencnece evescce- 352
Diagnostic Characters of Species ..........2...22-:-2--2::eccsececeeeseceeneeeeeeeeeeeneeees 352
JANSAY H SBEa OSI DAB rol 0 Se cece 352
POSTE TIO Typ iM gees arene etter eee rey ee eas, ee 20) eee 355

INTRODUCTION

- Remains of Nothrotherium and Megalonyzx have been recorded
from the cave deposits of northern California, but have not been
reported from the southern part of the state. In the Pleistocene
asphalt deposits of Rancho La Brea numerous remains of gravi-
grade edentates include both Nothrotherium and Megalonyzx,
along with representatives of the Mylodontidae. The genera
Nothrotherium and Megalonyx, which are usually thought of as
living in a region of more rugged topography than the habitat
of Mylodon, are but sparsely represented in this fauna, in con-
trast with the abundant remains of the Mylodontidae. In the

342 University of Califorma Publications in Geology [Vou.7

present paper Nothrotherium is doubtfully recorded as occurring
also in the type section of the San Pedro beds at San Pedro,
California.

The material of Nothrotherium available for study consists
of a skull and a tooth from the Rancho La Brea deposits; and
a second phalanx, tentatively assigned to the same genus, from
the San Pedro beds. Megalonyx is thus far represented by a
left humerus, a left caleaneum, a single metapodial of the
posterior foot, and various digital elements of both anterior and
posterior feet, all from Rancho La Brea.

The tooth of Nothrotheriwm was secured by the University
of California in 1906, while the skull of Nothrotherium was
excavated by the Southern California Academy of Sciences in
1909. The metapodial and digital elements of Megalonyx were
found closely associated and presumably belong to the same
individual. They were discovered by the University party at
Rancho La Brea in 1907; the humerus and ecaleaneum were
found in 1912.

The writer’s sincere thanks are due to Professor John C.
Merriam, under whose guidance this study was conducted. The
obligation of the writer is also expressed to Director F. H.
Daggett of the Museum of History, Science and Art of Los
Angeles, who kindly loaned the skull of Nothrotheriwm for study

and description.

NOTHROTHERIUM GRACILICEPS, n. sp.

Type specimen, a skull in the Museum of History, Science and Art,
Los Angeles, California, from the asphalt deposits of Rancho La Brea.

Paratype: A second superior tooth, no. 10485, Univ. Calif. Col. Vert.
Palae., from the asphalt deposits of Rancho La Brea.

Nothrotherium was first described by Lund,’ in 1839, under
the name of Coelodon maquinense from remains found in the
Cavern of Maquiné in Brazil. In 1878, Reinhardt? distinguished
another species, Coelodon escrivanense, also from a Brazilian
~~ 1 Lund, P. W., Recherches sur les mammiféres fossiles du Brésil, Ann.
Sci. Nat., 2. sér. (Zool.), vol. 11, p. 220, 1839.

2 Reinhardt, J., Kaempedovendyr-Slaegten Coelodon, Vidensk. Selsk.

Skr., 5 Raekke, naturvidenskabelig og mathematisk Afd., vol. 12, 3, pp.
253-349, V Tav. Kjobenhavn, 1878.

1913] Stock: Nothrotherium and Megalonyx 343

eave, differing from C. maquinense by the absence of a furrow
from the posterior face of the last superior tooth. The genus
received its present name from Lydekker* in 1889. Nothrother-
aum(?) shastense was described by Sinelair* from Potter Creek
Cave, Shasta County, California, in 1905, the type specimen
being a portion of the right ramus of the mandible without
teeth. Fourteen molariform teeth were also referred to this
species by Sinclair.

Diagnostic Characters of Species.—Skull slender ; larger than
in Nothrotherium escrivanense, and cranial portion more ele-
vated; point of greatest elevation on frontals; superior border of
zygomatic arch distinctly convex; median wall of tympanie bulla
pierced by a large aperture; post-palatine notch acute; post-
palatine foramina large; inner face of last superior tooth wider,
outer face more rounding and narrower than in N. shastense.

Skull—The skull from the asphalt beds is fairly well pre-
served and the sutures clearly defined. No teeth were associated
with this specimen. <A tooth found separate from the skull
corresponds in section to the second alveolus of the right side.
The skull is elongate and more nearly cylindrical than in the
genus Megalonyx. The muzzle tapers gradually forward from
the frontals. The greatest width of the skull occurs at the pos-
terior end of the zygoma. The tympanic bulla is prominent.
The transverse crest of the occiput divides this region into two
subequal areas.

The nasals (fig. 1) are long. Close to the median line each
nasal pushes a small wedge-like projection sharply into the
frontal. The dorsal surface of the nasals is convex in their
anterior half, becoming flattened posteriorly. The anterior
margin has been broken away.

In Nothrotherium graciliceps the point of greatest elevation
is reached at the junction of the middle and posterior thirds of
the frontal (fig. 3), while in N. escrivanense the highest point is
on the parietal. The frontals are widest across the anterior half.

3 Lydekker, R., Nicholson and Lydekker, Manual of Palaeontology,
ed. 3, vol. 2, p. 1299, 1889.

4Sinclair, W. J., New Mammalia from the Quaternary Caves of Cali-
fornia, Univ. Calif. Pub]. Bull. Dept. Geol., vol. 4, pp. 153-155, pl. 23, figs.
1-5a and 8, 1905.

344 University of California Publications in Geology [Vou.7

Skull, superior view, X %.

Fig. 1. Nothrotherium graciliceps, n. sp.
Rancho La Brea Beds.
Fig. 2. Nothrotherium graciliceps, nu. sp.

Rancho La Brea Beds.

Skull, inferior view, X %.

1913 J Stockh: Nothrotherium and Megalonyx 345

They are narrowed by the constriction of the cranium above
the base of the zygoma and indicated by the arch of the coronal
suture. Their surfaces show but a faint indication of the tem-
poral ridges, which swing back from the widest part of the
frontals to the median line, where they approach each other
at the coronal suture, but do not meet. In Megalonyx jeffersoni
these ridges are more pronounced and meet in the median hne
at the coronal suture. This difference may be due in part to
sex or to age. There is no blunt postorbital process as in
N. escrivanense. A shallow depression occurs posterior to the
end of the temporal ridge. On the orbital portion of the
frontal a sharp undulating ridge, which continues posteriorly
over the temporal, curving outward to form the inner border of
its zygomatic process, overhangs the orbitosphenoidal region, as
in WM. jeffersoni.

On the parietals the temporal ridges swing outward to the
widest portion of these bones above the posterior end of the
superior border of the zygoma. The parietals are distinctly
swollen at the posterior end of the temporal ridges. Between
the temporal ridges the parietals are flattened and show only a
suggestion of a sagittal crest, which is restricted to the posterior
half of the parietal region. In Megalonyx jeffersonvi the rugged
sagittal crest extends from the coronal suture posteriorly to the
lambdoidal crest, which in this form is also more sharply
defined than in Nothrotherium graciliceps. This difference is
probably not due to age. On the vault of the parietals below the
temporal ridges are several foramina, comparable to the ‘‘ venous

> of Leidy’s material of M. jeffersonii.

foramina’

The temporal is very long, with a comparatively small vertical
width. It is depressed above the mastoid area and close to the
lambdoidal suture. The trihedral zygomatic process is short,
with the superior border distinctly convex at the middle and a
slight corresponding concavity on the inferior border. In the
Brazilian species these two borders are straight. The zygomatic
arch of Megalonyx differs greatly from that of Nothrotherium
in bending more markedly downward and outward from the
cranial wall. A vascular foramen pierces the middle of the
lateral face of the zygomatic process.

346 University of California-Publications in Geology (Vou. 7

Behind the weak lambdoidal crest the rugose suwpraoccipital
slopes back at an angle of about 40° from the plane of the
parietals. In Nothrotherium the supraoccipital is more promi-
nent in superior view than in Megalonyz.

Fig. 3. Nothrotherium graciliceps, n.sp. Skull, lateral view, X %.
Rancho La Brea Beds.

Fig. 4. Nothrotheriwm graciliceps, n.sp. Skull, posterior view, X %.
Rancho La Brea Beds.

Fig. 5. Nothrotherium graciliceps, u.sp. Skull, anterior view, X %.
Rancho La Brea Beds.

The thickening of the mazillaries inferiorly (fig. 5) and the
pointed anterior margin of their palatal portions (fig. 2) seem
to indicate the original presence of premazillaries. The lateral
wall of the maxillary is convex above, becoming slightly concave

1913 ] Stock: Nothrotherium and Megalonyx 347

in its lower half as in the Brazilian species. A lhne of small
vascular foramina extends from the orbital opening of the infra-
orbital canal to a point posterior to the last alveolus. The
palate is elongate, slightly convex transversely, and appears to.
be more strongly pitted than in MW. jeffersonw. Posterior to the
last alveoli it becomes transversely concave. Anterior to the first
alveolus the palatal and lateral portions of the maxillary meet
almost at right angles. The tooth rows are nearly parallel. The
alveoli, with outer walls somewhat broken, are quadrate in form
with rounded corners, as is typical of the genus Nothrotherium.
With the exception of the last alveolus their lateral walls are
ribbed on the median line. All have the anterior wall concave
inwardly and the posterior wall convex, with the exception of
the first alveolus, which has its posterior wall shghtly concave.
The posterior wall of the last alveolus projects below the level
of the palate and is continued posteriorly as a strong ridge.

The lachrymal narrows ventrally as a bluntly rounded exten-
sion on the zygomatic process of the maxillary. The lachrymal
foramen is just anterior to the middle of the bone. <A deep
furrow extends downward from this foramen. The jugal was
not found with the skull.

The palatines are narrow and the palatal portion is restricted
chiefly to the margin of the postpalatine notch. The _post-
palatine foramina are much larger in Nothrotherium graciliceps
than in the Brazilian species, and the postpalatine notch is more
acute anteriorly than in the latter form. The anterior portion
of the vomer is broken; posteriorly it is sharply keeled in the
median line, as in Megalonyx jeffersoni, and narrows toward
the basisphenoid. In N. escrivanense the keel of the vomer
appears thickened posteriorly.

A portion of the tympanic bulla remains on the right side.
Unfortunately its connection with the palatine is too imperfect
to show clearly its relation to the pterygoid. Reinhardt states®
that in N. escrivanense the expanded backward projections of
the pterygoids form the tympanic bullae. The inner wall of
5 Reinhardt, J., Kaempedovendyr-Slaegten Coelodon, Vidensk. Selsk.

Skr., 5 Raekke, naturvidenskabelig og mathematisk Afd., vol. 12, 3, p.
336, Kjobenhavn, 1878.

348 University of California Publications in Geology [Vou.7

the right bulla is pierced by an elongate opening, which appears
not to have been present in N. escrivanense.

A small projection of the alisphenoid is suturally defined on
the left side, where it lies below the overhanging frontal ridge.
On the left side, where the tympanic bulla has been removed,
the alisphenoid is seen to form the roof of the auditory capsule.
The orbital fissure is large. The large combined opening of the
foramen rotundum and foramen ovale is about as far posterior
to the orbital fissure as the optic foramen is anterior to it.
Since the outer wall of the bulla, formed by the pterygoid, pro-
jects ventrally from the margin of the alisphenoid, the two
foramina open externally through the pterygoid. In Megalonyx
these two foramina open separately.

The concave basisphenoid narrows anteriorly, the apex being
indicated by a foramen opening above the vomer. Leidy states®
that in Megalonysx jeffersonu the sphenoidal surface is plane, and
cites a similar foramen above the vomer. The median portion
of the basioccipital is relatively much more prominent than in
N. escrivanense. The condylar foramen is small.

The glenoid fossa is but slightly coneave. The base of the
zygoma has a much greater anteroposterior diameter than in
M. jefferson. Below the rugose mastoid area is the large
stylohyal process. Anterior to the base of this process is the
large jugular foramen. In Reinhardt’s figure’ of the skull of
Nothrotherium escrivanense a much smaller foramen is indicated
in this region. The anteroexternal face of the stylohyal process
is grooved inferiorly. Superiorly this groove is converted into a
closed canal, the stylohyal canal, which leads to the jugular
foramen. Extending anterior to the process is a vertical plate
which abuts upon the posterior wall of the bulla. The stylohyal
process is continuous dorsally and posteriorly with the trans-
verse crest of the occiput (fig. 4), which is midway between the
lambdoidal suture and the foramen magnum. In Megalonyx
jefferson this erest is one-third the vertical distance from the

lambdoidal suture.

6 Leidy, J., A Memoir on the Extinct Sloth Tribe of North America, .

Smithson. Contrib. Knowl., vol. 7, p. 10, 1855.
7 Reinhardt, J., op. cit., Tab. 1, fig. 2.

1913 | Stock: Nothrotherium and Megalonyx 349

The foramen magnum is moderately large and subcireular in
outline. The superior margin is notched at the middle. In
N. escrivanense this border is entire. The occipital condyles are
similar to those of the Brazilian species, having their larger
articular face directed outward and forward.

Figs. 6, 7, and 8. Nothrotherium graciliceps, n.sp. Right second
superior tooth, no. 10485, XK 44. Rancho La Brea Beds. Fig. 6, view of
triturating surface; fig. 7, posterior view; fig. 8, lateral view.

Dentition.—A single tooth, no. 10485 (figs. 6, 7, and 8) corre-
sponds in section to the second alveolus of the right side. It
differs from a similar tooth (no. 8702) of Nothrotheriwm
shastense from the Potter Creek Cave in lacking the curvature
of the inner face. Its anterior face is longitudinally concave
and broadly convex transversely. The posterior face is slightly
coneave transversely, and the lateral faces are furrowed. The
triturating surface is deeply troughed transversely, especially
toward the inner side.

MEASUREMENTS OF SKULL AND DENTITION
Length of skull, anterior end of palate to posterior end of

COXKO OTIC COONAN ANGIE ee eee cee 300. mm.
Length of palate, anterior end to post-palatine noteh —........... 131.
Width of palate between second alveoli. -.......2.....2.2:-2-:20-0e0eee-o- + 22.9

Greatest width of MUZZ]e ooo... ceeeeeeeeceeececeee ceceeececeeeceeeeeceeeee
Greatest width above orbits .

Least width behind orbits -....0................ 2
Mastoid width above the stylohyal processes .............2..22.--2.--------- 112.6
Vertical height of occiput from plane of basioecipital to lamb-
CBOSS ESAT FAI tC 2) ese a ree re 83.
Length of dental series, from anterior wall of first alveolus to
Postenlormyalll\ ots Vast Al VCO MS eso a ceeccc sc c2e sce csecvencevenectsenoecec eee setee 57.5
M’, no. 10485, anteroposterior diameter at triturating surface... 13.

M?’, no. 10485, transverse diameter at triturating surface ........... 16.

350 University of California Publications in Geology [Vou.7

Relation to Nothrotherium shastense —The mandibular ramus
from Potter Creek Cave, although belonging to an adult indi-
vidual, is shorter than the lower jaw in the Rancho La Brea
species. The well-defined and open sutures in the skull of the
latter species seem to indicate a young adult.

Specimen 8202 from the Shasta cave is a first superior tooth
of the left side, which fits almost perfectly into the first alveolus
of the Rancho La Brea skull. It is a small tooth with posterior.
face slightly convex longitudinally and lateral faces furrowed.
Its anterior half is decidedly smaller transversely than the
posterior half. No. 8702* is a second superior tooth of the right
side. The outline of its triturating surface is very similar to
that of the Rancho La Brea specimen 10485, which is assigned
to the same position. Its inner face is, however, longitudinally
concave. The last superior alveolus of the left side in the Rancho
La Brea skull indicates a tooth wider on the inner or lingual
side and with a more rounding outer face of less width than is
shown in the corresponding tooth of V. shastense.’ Tooth 83377°
probably belongs to the inferior dentition.

Judging from the evidence presented, there is reason to
believe that the Rancho La Brea and Potter Creek Cave speci-
mens represent distinct species. Nothrotherium teeth have been
found also in Samwel Cave, Shasta County, California.

NOTHROTHERIUM(?), sp.

The second phalanx upon which this tentative determination
is based, was obtained by Dr. L. H. Miller and Dr. F. C. Clark
from the Upper San Pedro beds exposed just behind the yard
of the San Pedro Lumber Company at San Pedro, California.
A single dermal ossicle was also found in these deposits. The
marine Pleistocene fauna of these beds was described by Arnold”

8 Sinclair, W. J., New Mammalia from the Quaternary Caves of Cali-
fornia, Univ. Calif. Publ. Bull. Dept. Geol., vol. 4, 1905, pl. 23, figs. 3 and
3a. In fig. 3 the lower margin of the tooth is the anterior margin; in
fig. 3a the anterior face is shown.

9 Sinclair, W. J., op. cit., p. 154, pl. 23, fig. 8.

10 [bid., pl. 23, figs. 5 and 5a. ,

11 Arnold, R., The Palaeontology and Stratigraphy of the marine’
Pliocene and Pleistocene of San Pedro, California, Mem. Cal. Acad. Sci.,
vol. 3, pp. 420, pls. 37, June, 1903.

1913] Stock: Nothrotherium and Megalonyx Bol

in 1903. Miller’? lists the following vertebrates from the Upper
San Pedro Pleistocene :

Mammals— Birds—
Equus Aechmophorus, n. sp.
Bison Nettion carolinense (Gmelin)
Camelid Sturnella neglecta Audubon

The specimen, no. 19720, shown in figures 9, 10, and 11, is
very long and narrow, differing greatly in this respect from the
shorter and stouter second phalanges of Mylodon and Megalonyw.

Figs. 9,10, and 11. Nothrotherium(?), sp. Second phalanx, no. 19720,
x %. Upper San Pedro Beds, San Pedro, California. Fig. 9, superior
view; fig. 10, view of proximal face; fig. 11, lateral view.

The median groove of the distal trochlea is of the broad and
rather shallow type as in Mylodon, differing in this respeet from
Megalonyx. The depression at the end of the groove on both
the dorsal and ventral surfaces is broad, and is deepest on the
ventral surface. The condyles, unequal in size, are more
definitely constricted off from the rest of the shaft than in
Megalonyx, and have their postero-dorsal muscle ridges but little
developed. The two lateral facets of the proximal end are
divided by a thick median ridge, which widens superiorly and
inferiorly. Below this expansion the shaft is grooved for a
short distance on its inferior surface.

12 Miller, L. H., Contributions to Avian Palaeontology from the Pacifie

Coast of North America, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p.
115, 1912.

Bae University of California Publications in Geology |Vou.7

MEASUREMENTS OF PHALANX. No. 19720

Greatest length through middle of shaft -................. 73. mm.
Dey thy ort som oxamailite mC itece:ceereseesecaeeeseesceseeencese te eee 34.6
Width of «distal md) ie ieccccececec-ceecesscceseecevarecaus-sensteesaees 23.2

MEGALONYX CALIFORNICUS, n. sp.

Type specimen, a left humerus, no. 21003, Univ. Calif. Col. Vert. Palae.,
from the asphalt deposits of Rancho La Brea.

Paratypes: A left caleaneum, no. 20095; a third right metatarsal, no.
20001; various digital elements of anterior and posterior feet, nos. 20002—
20004 inclusive, Univ. Calif. Col. Vert. Palae., from the asphalt deposits
of Rancho La Brea.

Diagnostic Characters of Species——The material thus far
available represents a form somewhat smaller in size than
Megalonysx jeffersonii Desmarest. Head of humerus prominent,
two tuberosities farther separated than in M. jefferson; distal
trochlea wider than in M. jeffersonii, ulnar and radial facets of
equal width; dorsal surface of tuberous apex of internal condyle
with short closed canal. Neck of caleaneum with relatively
greater vertical width than in M. jeffersonii; postero-inferior
extremity not decidedly directed to either outer or inner side.
Articulating surface of third metatarsal for cuneiform tri-lobed.

Anterior Limb.—The head of the humerus, no. 21003 (fig. 12)
is more prominent in anterior view than in M. jefferson, due to
a wider separation of the two tuberosities. This separation in
M. californicus resembles that of Nothrotheriwm, but is not as
great as in Hapalops. The short and narrow bicipital groove
is distinet. The pectoral ridge, which is faintly indicated along
the upper half of the shaft, becomes prominent below the middle.
It is more distinct than in M. jeffersonii but less so than in
Mylodon. A slight projection occurs at the middle of the inner
border of the shaft.

The ‘‘musculo-spiral course’’ is well defined laterally, the
dorso-lateral margin differing from M. jefferson in protruding
slightly. A tendeney toward a similar projection is seen in
Mylodon. The distal trochlea is relatively wider than in M.
jefferson, the ulnar and radial facets being of the same width
in VW. californicus, while in the former species the radial facet is

1913] Stockh: Nothrotherium and Megalonyx 353

distinctly the wider. On the dorsal surface of the tuberous apex
of the internal condyle is a short closed canal, which is not
present in M. jeffersonii, Hapalops, or Mylodon.

Fig. 12. Megalonyx californicus, n.sp. Left humerus, no, 21003, ap-
proximately one-fourth natural size (i.e, X .27). Rancho La Brea Beds.

In the third left digit(?), no. 20002 (figs. 13 and 14) the
lateral faces of the proximal end of the first phalanx for meta-
carpal articulation are curved dorso-ventrally, and the coneave
median face narrows below. The outer offset is more abrupt than
the inner one. The outer face has a greater width, but the base

354 University of California Publications in Geology [Vou.7

of the inner face extends farther inferiorly. The groove between
the two distal condyles widens inferiorly.

Figs. 13 and 14. Megalonyx californicus, n.sp. Third digit of left
anterior limb(?), no. 20002, * 34. Rancho La Brea Beds. Fig. 13, lateral
view; fig. 14, superior view.

The second phalanx is heavier than in M. jeffersoni. The
median ridge of the proximal articular face is thick and widens
inferiorly, forming a slight protuberance below the inner facet.
The postero-dorsal ligamental ridges of the distal condyles are
very pronounced.

The osseous sheath on the inner side of the ungual phalanx
has been broken away. The upper portion of the proximal
articular face differs from M. jeffersonii in that the outer side
is produced backward farther than the inner side.

The tentative position of this digit is based upon Leidy’s
statement that in the first phalanges of the front foot ‘‘the
proximal or metacarpal articulation is a deep, vertical concavity,
extending from top to bottom of the bone, with an offset on each
side inferiorly in the median phalanx, but on one side only in

1913] Stock: Nothrotherium and Megalonyx Boe

the annular and index phalanges.’’'* There is an equal possi-
bility that this is a second left digit of the posterior foot.

No. 20003 belongs possibly to either the second or fourth digit
of the front foot. In the first phalanx there is no indication
of dorso-ventral curvature on the lateral faces of the proximal
end nor does the middle articulation narrow ventrally. An
offset occurs only on the inferior half of one side. The side
bordered proximally by the offset is distinctly narrower than
the opposite side. On the distal trochlear face, the condyle of
the shorter side widens inferiorly.

On the proximal articular face of the second phalanx the
surface articulating with the inferiorly broadened condyle of
the first phalanx is very slightly concave. The postero-dorsal
ligamental ridges are not prominent. The dorsal surface of the
smaller condyle is beveled laterally.

Figs. 15 and 16. Megalonyx californicus, n.sp. Left caleaneum, no.
20095, x %4. Rancho La Brea Beds. Fig. 15, view of right side; fig. 16,
view of proximal end.

Posterior Limb.—The left calcaneum, no. 20095 (figs. 15 and
16) agrees essentially with M. jeffersonii in its differences from
the calcaneum of WM. sierrensis as described by Sinclair.
Important differences exist, however, between the Rancho La
Brea calcaneum and the caleaneum of M. jeffersonii.

13 Leidy, J., A Memoir on the Extinet Sloth Tribe of North America,

Smithson. Contrib. Knowl., vol. 7, p. 35, 1855. ‘‘Median phalanx’’ here
means the first phalanx of the median digit.

14 Sinclair, W. J., op. cit., pp. 158-159, pl. 22, figs. 2 and 3.

396 University of California Publications in Geology [Vou.7

Although the caleaneum is of smaller size, the neck has a
relatively greater width than in M. jeffersonii. The superior
border of the fanlike tuber caleis is strongly concave, while the
inferior border is less arched than in the latter species. The
middle region of the inferior border is sharply edged. A depres-
sion occurs on the superior border close to the large astragalar
facet. Viewed from the proximal end (fig. 16), the postero-
inferior extremity is not decidedly directed toward either the
outer or the inner side, differing in this respect from both M.
jeffersonu and M. sierrensis. The lower half of the posterior
border is much thieker than the upper half.

The proximal end is, on the whole, similar to that of MW.
jefiersonu and has the following characteristics: The grooves
separating the three articular facets are well defined and are
broadest between the cuboidal and large astragalar facets.
Externally the large astragalar facet is flat, becoming shghtly
concave internally as it curves down to the inferior border. The
small astragalar facet is coneave in its longest (transverse)
diameter. The cuboidal facet is coneave vertically and curves
toward the external margin. The inner lip is flattened almost
at right angles to the rest of the surface and articulates with
the astragalus.

The facet for articulation of the cuneiform with the third
right metatarsal, no. 20001, is tri-lobed. The ventral lobe is
much the largest. Leidy states!’ that in WM. jeffersonii this sur-
face is quadrate. Of the two dorsal lobes, the lateral is larger
than the medial one. The proximal face is concave both dorso-
ventrally and transversely. The articular facet for the second
metatarsal has its greatest diameter dorso-ventrally, while the
articular facet for the fourth metatarsal is widest transversely.

The median distal convex surface of the metatarsal is oblique,
the lower end being nearest the inner side. At its ventral third
it curves shehtly outward. The broad offsets on each side follow
this course more or less. The median convexity is wide and well
rounded in its dorsal two-thirds but narrows in its ventral third,
the arch becoming pointed.

15 Leidy, J., Remarks on the Structure of the Feet of Megalonyx,
Trans. Amer. Philos. Soc., n.s. vol. 11, p. 107, pl. 6, fig. 1, 1860.

1913] Stock: Nothrotherium and Megalonyx got

In the co-ossified first and second phalanges of the third
right digit, no. 20004 (figs. 17 and 18), the offsets on each side of
the median coneavity of the proximal end are transversely con-
eave. This is especially noticeable on the inner offset, which is

‘

wider than the outer one. In M. jefferson there is ‘‘an oblique

716° The inner condyle of the distal

offset on each side inferiorly.
trochlea is well worn. The groove between the two condyles

widens inferiorly.

Fies. 17 and 18. Megalonyx californicus, n.sp. Third right metatarsal
and digit, nos. 20001 and 20004, * %4. Rancho La Brea Beds. Fig. 17,
lateral view; fig. 18, superior view.

The claw-core is broken away anterior to the ventral tuber-
osity in the ungual phalanx. The median ridge of the proximal
articular face is sharp and widens inferiorly. Just above the
median ridge on the overhanging process of the proximal end
is a small emargination. In M. jeffersonii the overhanging

16 Leidy, J.. A Memoir on the Extinct Sloth Tribe of North America,
Smithson. Contrib. Knowl., vol. 7, p. 44, pl. 18, figs. 17 and 18, 1855,

358 University of California Publications in Geology [Vou.7

process is more strongly notched. Following the margin of the
proximal end on each side is a ridge for ligament attachment.
The margin of the ventral tuberosity is distinctly set off from
its middle convex portion. The osseous sheath is thinnest on
the sides.

The terminal claw was retracted chiefly by a movement of
the entire digit upon the third metatarsal.

MEASUREMENTS C

Humerus— No. 21003
Gredtest: lengthy ...222..4:.4.2 ee 447. mm.
Width -at: tuberosities, -...... 2 ee 128.
Least width of shaft: ...2.22..202c iss oeeeeeso cece 60.5
Greatest width of distal) @xpansiom ’-..-2.2-..etcecesccsee ne essere 221.
Width of distall Grochilea, 22-2. ee 127.5

First Phalanx— No. 20002 No. 20003
Greatest ydepth: tc: eee eee ee 59.5 60.
Length of longer side 28.3 32.7
Greatest. ibrea ith: esses see seamen ee eee 38.2 39.6

Second Phalanx-— No. 20002 No. 20003
Greatest length through middle ......................-- 61.4 57.5
Depth of proximal ender 52.3 53.

TD eh oKelaler cope aC UMS epEWL CoN YG eee eee 34.5 32.1

Third Phalanx— No. 20002
Greatest? lengths (22s coe ee eee 149.4
Greates th depth coos ceeere sete eee 56.6

Caleaneum— No. 20095
Vertical width, of eck 2..:..222--:-...00fesccteeese ee 67.8
Greatest anteroposterior diameter) 2222 22cecccceeeecseees eee 206.
Greatest diameter of fanlike tuber caleis ...........22222.-.0-00--00-++ 202.
Greatest thickness of posterior border —-..2..2-:22..-2-:ecc-coocseeeeesseee= 38.2
least thickness of posterior border S22 16.

Third Metatarsal— No. 20001
Anteroposterior diameter through middle. - 22... 2-3 al2 cess 50.5
Depth of median vertical convexity of distal end .................. 74.9
Depth of proximal articular face 60.5

Greatest width 67.6
Co-ossified First and Second Phalanges— No. 20004
Length along middJe=of outer side: <._.2.eees ee ee 60.8
Greatest. depthvof proximal tace 22s 2c seeereenee seers 69.4
Depth of lateral condyle ‘of distal) end <2 eee 44.
Third Phalanx— No. 20004
Greatest: depth ... 22 3-42..45 9 24 92.7
Width just posterior to ventral tuberosity 52.

Transmitted August 15, 1913.

FORNIA PUBLICATIONS

eh. seis ts he
LLETIN OF THE DEPARTMENT OF — ~

Gee serology ; |
. 7, No. 18, pp. 359-372 Issued September 23, 1913 é
NOTES ON THE CANID GENUS ?
= TEPHROCYON ~ | -
; ~
Hen a ; oe )'6
JOHN C. MERRIAM
: * = 7 Eaunsonian Istije~ : Z
‘ $ “sp \ 3
2 OCT20 1979 | | ys

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UNIVERSITY OF CALIFORNIA PRESS.

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UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 18, pp. 359-372 Issued September 23, 1913

NOTES ON THE CANID GENUS
TEPHROCYON

JOHN C. MERRIAM

The genus Tephrocyon ineludes a group of American canids
with characters in some respects foreshadowing Aelurodon, and
in other points resembling Canis. These forms range from the
middle Miocene to early Pliocene, and are found distributed over
the western portion of the continent.

The material representing the described forms is mostly frag-
mentary and imperfectly known, and the species were in a con-
siderable part originally referred to Canis in the absence of
clearly distinguishing characters. Since the description of the
generic type of Tephrocyon, based upon a good skull and den-
tition from the Middle Miocene of Oregon, it has been noted
that a number of the species from the West-American Miocene
which were previously referred to Canis find a place in this
genus; and it is probable that still other species of uncertain
position belong here. On the other hand, it is probable that
some of the species based on fragmentary material and referred
to Tephrocyon do not represent that genus.

The following notes are presented with a view to bringing
together such information as is available relating to this group,
in the hope that this statement may serve to stimulate further
assembling of information, and more careful revision of the
forms related to T'ephrocyon.

360 University of California Publications in Geology |Vou.7

In preparing the following paper the writer has made a re-
examination of the type specimen of Tephrocyon, and several
figures representing phases of the structure not previously illus-
trated accompany this discussion.

For the loan of the type specimen from the University of
Oregon, the writer is much indebted to Professor A. J. Collier
and Professor J. F. Bovard.

GENUS TEPHROCYON

Type species Tephrocyon rurestris (Condon).

Skull of the type specimen short-muzzled, shortening of the
muzzle accompanied by backward extension of the premaxillaries
beyond the anterior ends of the nasal processes of the frontals,
auditory bullae large. Paroecipital process prominent. Man-
dible* heavy, uncommonly convex below the anterior border of
the masseteri¢ fossa. Crushing region of the molar teeth rela-
tively large. M* and M? with inner lobe relatively wide antero-
posteriorly. M, with well-developed metaconid and large heel.
M, relatively long anteroposteriorly, paraconid ridge or tubercle
distinct, antero-extenal ridge of the cingulum strongly marked.
Premolars usually relatively short. P* with an ineipient proto-
style in the type specimen of the genus. Posterior opening of
the vertebrarterial canal of the atlas situated farther back than
in Canis.

The forms that have been referred to Tephrocyon include the
following:

T. rurestris (Condon). Maseall Beds, Oregon. Middle Mio-
cene. |

T. hippophagus Matthew and Cook. Snake Creek, Nebraska.
Early Pliocene.

T. temerarius (Leidy). Sands of the Niobrara River, Snake
Creek?, and Whistle Creek, Nebraska; Mohave Beds, Mohave
Desert, California. Upper Miocene.

T. kelloggi Merriam. Virgin Valley Beds, Nevada, Middle
Miocene; Cedar Mountain, Nevada, Middle to Upper Miocene.

T., near kelloggi Merriam. Thousand Creek Beds, Nevada,
Early Phocene.

1913] = Merriam: Notes on the Canid Genus Tephrocyon 361

Tephrocyon, sp. (Matthew and Cook). Snake Creek, Ne-
braska, Early Pliocene.

_ Tephrocyon?, sp. (Merriam). High Rock Canyon, Nevada.
Middle Miocene.

T. vafer (Leidy)? Snake Creek, Nebraska. Early Pliocene.

So far as known, the several species may be characterized as
follows:

T. rurestris. Mandible short and massive, relatively convex
below anterior end of the masseteric fossa. Inferior premolar
series short, inferior premolars without anterior cusps, meta-
eonid of M, moderately developed, M, relatively shorter antero-
posteriorly than in 7. kelloggi, but longer than in T. hippophagus
and 7’. temerarius.

T. hippophagus. Characters in general much as in 7. rures-
tris. Inferior premolar series somewhat longer than in 7. rwres-
tris. Inferior premolays larger and thicker than in 7. rurestris,
and with anterior cusps on P,, P;, and P,. M, slightly shorter
and relatively thicker transversely than in 7’. rurestris.

T. kelloggi. Mandible more slender than in 7. rurestris and
T. hippophagus. Inferior premolar series relatively long. In-
ferior premolars small, relatively simple, and without anterior
cusps. Metaconid of M, relatively large. M, relatively long

anteroposteriorly.
T. temerarius. Mandible more slender than in 7. rurestris

and T. hippophagus. Mandible of Mohave Desert specimen
lighter than in 7. kelloggi; other referred specimens not heavier
than T. kelloggi. P, with anterior cusp or tubercle, other pre-
molars imperfectly known. Metaconid of M, of medium size.
M, relatively much shorter than 7. kelloggi, and shghtly shorter
than in the other two species.

362 University of California Publications in Geology [Vou.7

COMPARATIVE MEASUREMENTS

n 5 oe 5 pt 3 , 2 o
Pa Raf mf oso 2
nO BaD oS kx
2o ‘sao =o DERS
tale a & Cre Se rites
aan staal 4a : a
Bo. A -9 Foo
ei a A, 4
ia iat ms
; : ; a a a
Length of mandible from anterior side
of P| to posterior side of condyle ........ a112 mm. 107. 033
Height of mandible below protocone of M, 20. 22.5 21. 16.
Greatest thickness of mandible below
teal Omnia CLO fe, SV es ce wa ssc ves cee ee — 10. 9. 8.4
iP, anteroposterior diameter 2227-2. 7.5 8. 6. eS
P,, anteroposterior diameter ...................-.- 2: 9.3 6.7 7.
Po anteroposterior diameter ...................--- 11.5 12. 8.4 8.5
M anteroposterior diameter ...............-..---- 20. 19.8 15. 17.
M, transverse diameter of heel —................ as.7 8.3 7. 6.5
M., anteroposterior diameter -..................: 11.5 10.1 10.5 9.
M,, greatest transverse diameter -............... 6.8 6.9 Gun 5.7
Length, posterior side inferior canine to
DOStCTIONESIGe Vy lore ee 63.4 65.5@ 61. 228
. or . a . . &
Length, posterior side inferior canine to
posterior side P ..----eee 33 a 35.5 30) 4a

a, approximate.

TEPHROCYON RURESTRIS (Condon)
Canis rurestris Condon. The Two Islands, p. 139, pl. 18, 1902.
Tephrocyon rurestris. Merriam, J. C., Univ. Calif. Publ., Bull. Dept.
Geol., vol. 5, p. 6, 1906.

The type specimen was originally no. 382 in the private col-
lection of Professor Thomas Condon. It is now in the collections
of the University of Oregon. The fragmentary specimen consist-
ing of four upper cheek-teeth shown in the lower right hand
corner of Condon’s figure of Canis rurestris (Two Islands, pl.
18) does not pertain to the type of Tephrocyon rurestris. These
detached teeth represent a species of Temnocyon, near T. alti-
genis Cope from the John Day Series.

The type specimen, consisting of a good skull with the atlas
and a portion of a tibia, was obtained in the Maseall Beds near
Cottonwood, Grant County, Oregon. As nearly as could be
determined in conversation with Professor Condon, this speci-
men was found at the type locality of the Mascall Beds. This
horizon is of Middle Miocene age. Other fragmentary material
from the Mascall may represent this species.

1913] Merriam: Notes on the Canid Genus Tephrocyon 363

The skull and dentition of Tephrocyon rurestris represents
a rather short-headed, heavy-jawed dog with an unusually large
crushing area on the molars.

The accompanying figures present the principal characters
of this species. (See figs. 1 to 5.)

Figs. 1 and 2. Tephrocyon rurestris (Condon). Type specimen, X 1%.
Mascall Beds, John Day Valley, Oregon. Fig. 1, lateral view of skull;
fig. 2, superior view of skull.

364 University of California Publications in Geology (Vou.7

Figs. 3 and 4. Tephrocyon rurestris (Condon). Dentition of type speci-
men, natural size. Mascall Beds, John Day Valley, Oregon. Fig. 3,
superior dentition, occlusal view; fig. 4, inferior dentition, occlusal view.

an
hi

Fig. 5. Tephrocyon rurestris (Condon). Type specimen. Posterior
view of skull with atlas, X 1%4. Mascall Beds, John Day Valley, Oregon.

TEPHROCYON HIPPOPHAGUS Matthew and Cook
Tephrocyon hippophagus Matthew and Cook. Bull. Am. Mus. Nat. Hist.,
vol. 26, p. 374, 1909.

To this species Matthew and Cook referred eight lower jaws,
and a portion of an upper jaw from Snake Creek. The Snake
Creek Beds are considered by Matthew and Cook as representing
an early phase of the Phocene.

After an examination of the type specimen of 7. hippophagus,
and a comparison with the type of 7. rurestris of an excellent
cast, kindly furnished by Dr. Matthew, there seems no doubt

1913] Merriam: Notes on the Canid Genus Tephrocyon 365

that this is a form closely related to Tephrocyon rurestris and
yet is specifically distinet from it.

Fig. 6. Tephrocyon hippophagus Matthew and Cook. Lower jaw of
type specimen, external view, X 34; and occlusal view of teeth natural size.
Am. Mus. N. H., no. 13836. (After Matthew and Cook).

TEPHROCYON TEMERARIUS (Leidy)

Canis temerarius Leidy. Proce. Acad. Nat. Se. Philad., p. 21, 1858.

Canis temerarius Leidy. Jour Acad, Nat. Se. Philad., vol. 7, p. 29, pl.
1, fig. 12, 1869.

? Tephrocyon ef. temerarius. Matthew and Cook, Bull. Am. Mus. Nat.
Hist., vol. 26, p. 376, 1909.

Tephrocyon temerarius. Peterson, O. A., Mem. Carneg. Mus.. vol. 4,
p. 268, 1910.

The typical material of this species consisted of a piece of
a lower jaw containing the ecarnassial tooth, and a portion of
an upper jaw with two teeth both badly preserved. This material
was obtained by Dr. Hayden from the Niobrara Sands. The
horizon is presumably Upper Miocene. The lower jaw and M,
figured by Leidyt show form and dimensions closely similar to
those of a specimen obtained by Peterson? from beds at Whistle

1Leidy, J., Jour. Acad. Nat. Se. Philad., vol. 7, second series, pl. 1
fig. 12, 1869.

2 Peterson, O. A., Mem. Carneg. Mus., vol. 4, p. 268, 1910.

366 University of California Publications in Geology [Vou 7

Creek, Nebraska, possibly belonging to late Miocene or Pliocene
deposits.

A portion of a lower jaw (no. 19402), with P, to M, inclusive,
from the Mohave Beds of the Mohave region, California, very
closely resembles the type of Leidy’s Canis temerarius from the
Nebraska formation and also resembles the specimen from Whistle
Creek, Nebraska, referred to this species by Peterson. M, of the

Fig. 7. Tephrocyon temerarius (Leidy). Occlusal view of teeth and
external view of lower jaw, natural size. (Carneg. Mus. Cat. Vert. Foss.
no. 2404). (After Peterson).

Mohave specimen very nearly approaches in form and dimen-
sions the original figured specimen of Canis temerarius (Leidy),
and the Mohave species is almost identical in form and dimen-
sions with the corresponding parts of the specimen described
by Peterson.

The specimen from Mohave Beds (figs. 84 and 8b) represents
a species of Tephrocyon differing shghtly from those thus far
known in the Great Basin region. The relationship of this form
to the genus Tephrocyon is shown in the large size of the meta-
eonid and of the crushing heel of M,, and in the presence of a
well-developed paraconid with a large antero-external shelf on
the cingulum of M.,.

The Mohave form is distinguished from Tephrocyon rurestris
and T. hippophagus by the smaller, more slender teeth. From
T. kelloggt it differs in the relatively larger M, and smaller M,,
and smaller metaconid of M,. M, in the Mohave specimen
measures 17mm. in anteroposterior diameter as compared with

1913] Merriam: Notes on the Canid Genus Tephrocyon 367

9mm. in anteroposterior diameter in M,. In 7. kelloggi the
anteroposterior diameter of M, is 15 mm.; of M,, 10.5 mm. There
is a small hypoconulid on the heel of M, in the Mohave speci-
men, while in the type of 7. kelloggi this tubercle is not sug-
gested. The heel of M, seems somewhat shorter than in 7. kel-
loggt.

Figs. 8a and 8b. Tephrocyon temerarius (Leidy). A portion of the
mandible with dentition. No. 19402, natural size. Mohave Beds, Mohave
Desert, California. Fig. 8a, superior view; fig. 8b, lateral view.

P, and P,, both possess a posterior cusp and a posterior basal
tubercle. P, shows a small anterior basal tubercle. The anterior
side of P, is not preserved.

Several specimens of mandibles slightly larger than no. 19402
represent a Tephrocyon species from the Mohave Beds very near
T. temerarius. It is possible that they belong to another species,
but age and sex are presumably competent to account for the
differences.

TEPHROCYON KELLOGGI Merriam, J. C.
Tephrocyon kelloggi Merriam. Univ. Calif. Publ., Bull. Dept. Geol.,
vol. 6, p. 235, 1911.
To this species there have been referred several jaws and
detached teeth from the middle Miocene Virgin Valley Beds
of northern Nevada. <A single tooth from the early Pliocene of

368 University of California Publications in Geology |Vou.7

Thousand Creek, Nevada, closely approaches this species, and a
lower carnassial from Cedar Mountain in middle Nevada repre-
sents a closely allied form.

This species differs farther from all of the other three species
than any one of these three differs from the others and further
study may suggest subgeneri¢e separation. The mandible is more
slender than in 7. rurestris or in T. hippophagus; the premolars

9a 9b

Figs. 9a and 9b. Tephrocyou kelloggi Merriam. Type specimen, X 14.
No. 11562. Virgin Valley Beds, Virgin Valley, Nevada. Fig. 9a, M, and

Stewart Valley Beds, Nevada.

are relatively smaller, more simple, and more widely spaced than
in the other forms; M, and the heel of M, are relatively long;
and the metaconid of M, is unusually large and high. The char-
acters of the jaw and dentition are in general those of Tephro-
cyon, and the species is evidently nearer the group of three
ineluding 7. rurestris, T. temerarius, and T. hippophagus than
to any other known dogs.

Llb

lla

Figs. lla and 11b. Tephrocyon kelloggi Merriam.

M,, unworn tooth,
no. 10651, X 1%. Virgin Valley Beds, Virgin Valley, Nevada. Fig. 11a,
outer side; fig. 11b, superior side.

Fig. 12. Tephrocyon kelloggi Merriam. M.,, worn tooth, no. 11474,
x 1%. Virgin Valley Beds, Virgin Valley, Nevada.

Fig. 18. Tephrocyon, near kelloggi Merriam. M_., no. 12542, x 1%.
Thousand Creek Beds, Thousand Creek, Nevada. %

1913] Merriam: Notes on the Canid Genus Tephrocyon 369

The specimen from the Cedar Mountain region of middle
Nevada referred to above consists of the greater portion of a
single lower carnassial (see fig. 10) from Stewart Valley (local-
ity 2027). It is almost identical in form with M, of the type
specimen of Tephrocyon kelloggi from Virgin Valley, Nevada.
The very slight differences between these two specimens are due
in a large part to the fact that the Stewart Valley specimen is
unworn, while the type has been subjected to moderate wear.

In addition to showing closely similar dimensions, the Stew-
art Valley specimen resembles M, of the type of 7. kelloggi in
the very long heel, and the very large metaconid. There is also
close correspondence in a number of minor details, as in the posi-
tion and form of the small inner and outer tubercles intermediate
between trigonid and talonid, the presence of a faint ridge of
the cingulum on the outer side of the heel, and the development
of a faint ridge on the outer portion of the posterior end of
the heel.

COMPARATIVE MEASUREMENTS
No. 19767 ~—‘T. kelloggi

M, anteroposterior diameter of heel on inner side.. 4.3 mm. 4.1
M_,, greatest transverse diameter of heel ................. 6.5 7.

SPECIES OF UNCERTAIN RELATIONSHIPS

Several fragmentary specimens representing forms in or
near Tephrocyon have been deseribed in recent palaeontologic
papers. The exact position of the forms represented by this
material can not be satisfactorily determined until better speci-
mens are obtained.

Fig. 14. Tephrocyon?, sp. Part of lower jaw with ee and M.
External view X 3, oeclusal view ot teeth natural size. (Amer. Mus. Nat.
Hist., no. 13843). (After Matthew and Cook).

370 University of California Publications in Geology (Vou. 7

A jaw fragment with M, and P, (no. 13843) obtained by
Matthew and Cook? at Snake Creek, Nebraska, is doubtfully re-‘
ferred to Tephrocyon. It represents a form one half larger than
T. hippophagus. The heel of M, in this form seems shorter than
in any other specimen referred to Tephrocyon.

15d Lob
Figs. 15a and 15b. Tephrocyon?, compare rurestris (Condon). No.
12503, natural size. Virgin Valley Beds, Little High Rock Canyon, Humboldt
County, Nevada. Fig. 15a, M, and P, inner view; fig. 15b, M, occlusal
view.

Figs. 16a and 16b. Tephrocyon?, sp. No. 12504, natural size. Virgin
Valley Beds, High Rock Canyon, Humboldt County, Nevada. Fig. 16a,
outer side; fig. 16b, occlusal view.

A jaw fragment with M, and P, (no. 12503) from the Middle
Miocene of Little High Rock Canyon, Humboldt County, Nevada,
is compared with Tephrocyon rurestris by Merriam.* The gen-
eral form and measurements are near those of the type specimen
of T. rurestris. The metaconid of M, seems relatively a little
smaller and the protoconid and paraconid more acute. This
difference, especially as represented in the figure, is largely due

3 Matthew, W. D., and Cook, H. J., Bull. Am. Mus. Nat. hist., vol. 26,
p. 376, 1909.

4 Merriam, J. C., Univ: Calif. Publ. Bull. Dept. Geol., vol. 6; p. 239
and 240, text-figs. Sa and 8b, 1911.

1913] Merriam: Notes on the Canid Genus Tephrocyon 371

to difference in wear. It will be necessary to have more material,
and especially to secure a specimen with M,, before the exact
relationship of this form can be determined.

A portion of a mandible with M, and P, (12504) from the
Middle Miocene of High Rock Canyon, Humboldt County, Nev-
ada, represents a species larger than that from Little High Rock

‘anyon. P, differs from that of Tephrocyon rurestris in the
possession of an anterior cusp. The entoconid of the heel of M,
is relatively smaller than in the specimen from Little High Rock
Canyon. In several characters this specimen resembles 7’. hippo-
phagus more nearly than it does 7’. ruwrestris, but it is probably
distinct from both species.

Although the specimens from the High Rock and Little High
Rock beds resemble the typical Tephrocyon, 1 many respects
they are quite different from 7. kelloggi, and future study of
this group of eanids may show that the fragmentary forms last
described are separable at least by subgeneric characters from
the 7. kelloggi type.

Matthew and Cook® have compared fragmentary material
from the Snake Creek Beds to Canis vafer Leidy, and have ten-
tatively referred this form to Tephrocyon. It seems to the writer
doubtful whether Canis vafer can be included in the same generic
eroup with Tephrocyon rurestris and T. hippophagus.

RELATIONSHIPS OF TEPHROCYON

Writers® who have expressed an opinion on the affinities of
Tephrocyon have considered this group as distinguished by char-
acters in some respects like those of Canis, and in some particu-
lars like those of Aelurodon. The further study of the group
bears out these assumptions, and future work may show that
both Canis and Aelurodon are derivatives of the Tephrocyon type.
Later study will probably reveal many varieties of the Tephro-
cyon group as yet unknown, some of which will be more lke

5 Matthew, W. D., and Cook, H. J., Bull. Am. Mus. Nat. Hist., vol. 26,
p- 376, 1909.

6 Merriam, J. C., op. cit., 1906.
Matthew, W. D., and Cook, H. J., op. cit., 1909.

—— * Fae FE

Sey University of California Publications in Geology [Vou.7

Aclurodon than the species now available. Some of the frag-
mentary specimens to which reference has been made above show
characters verging close to Canis.

Bear-like characters, such as are seen especially in M, and
M, of Tephrocyon kelloggi, are not considered as indicating that
this group is ancestral to any division of the Ursidae. T. kelloggi
may, however, lead to a very specialized side branch of the
Caninae. ;

Transmitted June 28, 1913.

JOHN C. MERRIAM

ate bats ax

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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 19, pp. 373-385 Issued September 24, 1913

VERTEBRATE FAUNA OF THE ORINDAN
AND SIESTAN BEDS IN MIDDLE
CALIFORNIA

BY
JOHN C. MERRIAM

PAGE

HNerattans@ GLA Url O Wn oes anaes ence Fe ae Bees Saco tates 2a sees suesae cease see ts enue ache e¥ere etece 373
TED OTN NCS) oe ae 375
INE OUT ATL OMS) Seveecse. cere, tcacctes ec aeel ese eves ceca. 2 Seneaeet se sueetuusecttesendseb Wee ossctes 375

TE Loto ofeviertonal((L)) MCope IONIC a ato} og COS AV ee eee ee een 376
INeohupparion! ory) Mery Chip pus: 222c.c..ce-c2ccc-cccccececctecceecnece--enneeeefeerecseceensaeee 376
Provonuppinie (yr aStragalus <2..222e-.cecc scence cece eoeee uc enteal neseiecesteeeeteseee ett 377
HPTOSUNENMOPS|G2i)iy SP up ..-coc--ceezcee--5--=seceees --ce-tec--sosvesatestiscsseteseoceceacecedsseecedicuseses 377
(CATER EH BU TAYE eS 380
JER ROYOLE GAY =D NOESY ep) tS 9 OF wee Pe Peo 380
YEADON C) AXeTaU TE LEYS 4S) aime ees ts ce ea te ee 381
Metra elOdomiG?\ 5 Spe, cesecccecaccecncezcebencdtestecesccucqqa-ctees sarcscoetocdeeeeststesncocestsieee-tnss OGL
Wipowdesslecomter (Merriam, J. C.)) <2scccs: sets ccteceeseceeteeeseteceaeeeeeeeeneneesseets OOF
TCS ONES Si 9) ecg ae re 383
DE AgaN ee RASS O ON OS ae Pe 383
Age of the Orindan and Siestan Vertebrate Faunas ~...............2............. 384

INTRODUCTION

The Orindan and Siestan formations occurring in the hills
immediately to the east of Berkeley form the larger part of a
thick accumulation of fresh-water and alluvial beds resting
uncomformably upon the marine Miocene. The Orindan forma-
tion is the lower portion of these beds, and comprises a great
thickness of clays, shales, sands, conglomerates, and tuffs, with
occasional beds of limestone. The Orindan is followed by a

374 University of California Publications in Geology [Vou.7
series of igneous rocks consisting mainly of andesite and basalt.
The Siestan rests upon the lavas covering the Orindan, and is
in turn covered by a volcanic series made up largely of basalt.

The section, from the base of the Orindan to the top of the
lavas above the Siestan, contains no marine fossils. It shows
seattered through it a few remains of fresh-water Mollusca and
Crustacea, land Mollusea, land plants, and land or fresh-water
vertebrates. The accumulation as a whole is evidently the result
of deposition in a basin which was at times occupied, at least
in part, by fresh water, and at other times may have received
purely alluvial deposits.

As our knowledge of the land fauna of the California region
west of the Sierras and north of Tehachapi is very meagre, the
writer has made special effort during the past ten years to secure
material which might furnish some information as to this phase
of the palaeontologie record. The great thickness of strata in
the Orindan and Siestan seems to offer some of the most favorable
places to search for vertebrate forms. The beds being so situated
that the relation of the vertebrate fauna to the earlier marine
Tertiary faunas is determinable, any information acquired is
especially valuable for use in connection with work on the corre-
lation of the great marine marginal province and the epicon-
tinental Great Basin province of western North America.

Being easily accessible for investigation, the Orindan and
Siestan formations have probably been examined for vertebrate
remains more earefully than any other non-marine formations in
the California area of the Pacifie Coast marginal province. In
spite of the efforts put forth, only a very scant fauna has been
obtained in the course of the eighteen years since the first sys-
tematie search was conducted in these beds. Although the results
of our investigation of this fauna are very unsatisfactory, it
seems desirable to put the available information on record, as
the known relation of these formations to the marine Tertiary
of middle California gives unusual significance to all data ob-
tained. It is hoped that presentation of the evidence offered
here may serve as a stimulus and a euide to future students
of the Orindan and Siestan, so that a much more satisfactory
representation of the fauna may be secured.

1913 | Merriam: Fauna of Orindan and Siestan 375

EQUIDAE

Remains of early horses have been found at two localities in
the Orindan beds. No specimens representing this group are
certainly known from the Siestan. It is stated that bones of a
horse were found in a shaft sunk in Siestan beds on Frowning
Ridge near the upper end of Telegraph Canon, but the writer
has been unable to obtain any definite information as to this
occurrence. Two teeth representing species near Neohipparion,
and an astragalus that may well represent a horse of Miocene
age have been obtained near Bolinger Canon. <A single tooth
was obtained by Mr. J. P. Buwalda from Mr. Williams, who
discovered it in extensive Orindan exposures about two and one-
half miles from the mouth of Tassajara Canon, on the southwest
side of Mount Diablo. The specimen from Tassajara Canon and

ie;

Figs. la to le. Neohipparion, sp. Upper premolar. No. 19830, natural
size. Orindan beds, southwest of Mount Diablo.

Fig. 2. Neohipparion or Merychippus. Upper premolar. No. 1323,
natural size. Orindan?, west of Bolinger Cafion.

Figs. 38a and 3b. Hipparion(?) or Neohipparion. Upper cheek-tooth.
No. 1324, natural size. Orindan?, near Bolinger Cafion.

376 University of California Publications in Geology [Vou.7

the better preserved tooth from Bolinger Canon (no. 1324) seem
to represent different species. The second specimen (no. 1323)
from near Bolinger Canon is imperfectly preserved, but is pos-
sibly different from the other two teeth.

NEOHIPPARION, sp.

Specimen no. 19830, from Orindan beds two and one-half
miles southwest of Tassajara Post Office.

This form is represented by a single tooth, P? (figs. la to 1c).
The crown is rather large, it has been well cemented, and the
outer styles are strong. The flattened protocone is distinct
almost to the base. The anterior and posterior fossettes are
narrow transversely, and the borders are formed into numerous
deep pleations. The two fossettes are lightly connected. If
this connection is due to lack of wear, it is evident that the crown
was not greatly elongated.

This tooth does not agree closely with any form known to the
writer, but it does not seem desirable with the present material
to give it a special designation other than to recognize it as a
distinct form. <A species of Neohipparion apparently different
from that from near Tassajara is known from late Tertiary beds
near Ricardo Post Office on the northwestern boundary of the
Mohave Desert.

MEASUREMENTS OF CHEEK-TootTH No. 19830

P2, greatest anteroposterior diameter of crown ...........--.---------------- 25.8 mm.
P2, greatest transverse diameter of CrOWD ...............-----0:---cc-s0eceeeeee=0 21.6
2, anteroposterior diameter of protocone ...............-.-------.---c-cce------ 8.2

HIPPARION(?) OR NEOHIPPARION

Specimen no. 1324, from Orindan beds near Bolinger Canon.

A fragmentary tooth (no. 1324, figs. 83a and 3b) differs from
that seen in the form from Tassajara Canon in the round
protocone and more pronounced plication of the walls of the
anterior fossette. This type does not differ greatly from one
of the Neohipparion specimens from near Ricardo on the Mohave
Desert.

1913] Merriam: Fauna of Orindan and Siestan SPerl

MEASUREMENTS OF UPPER CHEEK-TooTH No. 1324

Greatest anteroposterior diameter ..........2...2....:::::c21:cecceceeeeeeeeeeteeeeeeeees 24.2 mm.
Anteroposterior diameter of protocone ..........2....2--..0...--222e eee 6.2

NEOHIPPARION OR MERYCHIPPUS

A specimen (fig. 2, no. 1323) from beds presumably of
Orindan age west of Bolinger Canon is smaller than no, 1324.
The protocone is free to the base, the fossettes seem a little wider
transversely and show less marked plications than in the speci-
mens tentatively referred to Hipparion.

This form may represent a species distinct from the other
two forms of the Hipparion group or may be included in the
genus Merychippus.

MEASUREMENTS OF CHEEK-TooTH No, 1323

Approximate greatest anteroposterior diameter .........-.0-0-...-.-..- 18.3 mm.
Approximate greatest transverse (liameter —..---- ne 17.7
Greatest anteroposterior diameter of protoeone 2.00. 5.7

PROTOHIPPINE(?) ASTRAGALUS
An astragalus (fig. 4, no. 9858) from near Bolinger Canon
represents a stage of development approximating that of certain

Fig. 4. Protohippine(?) astragalus. No. 9858, natural size. Orindan?,
near Bolinger Cajon.

Miocene horses. The deeply-cut groove of the trochlea is rather
narrow, and is markedly oblique.

378 University of California Publications in Geology [Vou.7

PROSTHENNOPS(?), sp.

Some months ago the class in field geology, working under
the direction of Professor Andrew C. Lawson, obtained in fresh-
water shales of the Siestan beds near Bald Peak a specimen
representing a portion of the skull of a dicotyline form not
previously known from California. The specimen consists of a
portion of the cranium showing part of the palate with M? and
M® of the right side, and the left cheek-tooth dentition except-
ing M'. The teeth are much worn, but enough of the characters
are indicated to make possible an approximate determination.
The fragment containing the anterior portion of the upper denti-
tion of the left side was separate from the portion with the molar
teeth when it came into the writer’s hands. It seems to fit

Fig. 5. Prosthennops(?), sp. Upper cheek-teeth. No. 19826, natural
size. Siestan beds, near Bald Peak.
imperfectly against the anterior end of the piece with the molars.
If this diagnosis of the relation of these pieces to each other is
correct, a gap approximately fifteen millimeters long between
P* and M° represents the space occupied by M?.

The most anterior element of the cheek-tooth series, con-
sidered as P?, is double-rooted. The posterior root is wide trans-
versely and suggests incipient division into two. The crown is
relatively wide posteriorly, and shows a large anterior tubercle
with a posterior tubercle or cusp which has an anteroposterior
diameter not more than half that of the anterior tubercle. It is

1913 | Merriam: Fauna of Orindan and Siestan 319

barely possible that other tubercles were present, but in the
present worn condition of the crown no evidence of other features
appears. This tooth is near the stage of advance in Tayassu,
but is perhaps a little less advanced in that the posterior root
ig narrower and not distinctly divided. If the crown were com-
plete it might show the posterior tubercle or cusp divided into
two. This tubercle is, however, smaller than in T'ayassu.

The tooth considered to represent P* is nearly quadrate, the
hypocone region being slightly less developed than the protocone
region. The posterior or hypocone-metacone region is narrower
anteroposteriorly than the protocone-paracone region. The stage
of advance of this tooth is approximately that of T’ayassu.

P* is quadrate in outline, but the hypocone-metacone region
is narrower than the protocone-paracone region. The stage of
advance is near that of Tayassu, with a tendeney to show a
smaller posterior lobe than in the Siestan form.

The proportions of M* and M* are much as in Tayassu or in
Prosthennops.

The material available indicates that the form represented
by specimen 19826 is near the stage of development of Tayassu
with the exception that the premolars are shghtly less advanced.
The character of the upper canines and the length of the diastema
are not known.

So far as represented, the characters in this specimen are those
of the genus Prosthennops known from the Upper Miocene and
Lower Pliocene. A specimen from the Pliocene of Thousand
Creek in northern Nevada referred to Prosthennops' resembles
this specimen in the general proportions of the teeth, but appar-
ently differs somewhat in the character of the crowns. As nearly
as one can judge from the imperfect material, P? is quite differ-
ently constructed in the two forms. From the evidence available,
it does not seem probable that they represent the same species.

Although the material is not at hand for a satisfactory com-
parison of the Siestan specimen with the Prosthennops species
known east of the Rocky Mountains, it is probable that the
Siestan form is distinct from any of the described species.

1 Merriam, J. C., Univ. Calif. Publ, Bull. Dept. Geol., vol. 6, p. 278, 1911.

380 University of California Publications in Geology [Vou.7

MEASUREMENTS
No. 19826
P2, anteroposterior diameter 22.2222. eee cece eee 9.2 mm.

2, transverse, diameter ..2:-222.2.26:-2.ccseeeccce oe ete eee ects
P3, anteroposterior diameter
es OTC ALCS yg WLCUG I ee cc 2. sentae aes cates ae see eee ese sane Fie eens reeeerae aes
P4, anteroposterior diameter
a wor eates tis widoby Sac e-cesces ste essere eee ene eee
M}, anteroposterior diameter

2, anteroposterior diameter
Mies OVCALCS Gi WIC cess. cuca esaeeesa asses seeee sec es eee nn
M*, anteroposterior diameter
Mis, are atest” watly x sc as ta eect) cane eee 14.4

Fig. 6. Procamelus(?), sp. Portion of anterior limb. No. 1560, * ¥.
Orindan, Bolinger Canon. :

Fig. 7. Pliauchenia(?), sp. Portion of cannon bone. No. 1982, x 4.
Siestan, Siesta Valley.

1913 | Merriam: Fauna of Orindan and Siestan 381

PROCAMELUS(?), sp.

A portion of the anterior limb (fig. 6, no. 1560) of a camel
somewhat larger than the existing Hama was found at locality
299 near the middle of the Orindan beds at Bolinger Canon.
This specimen does not show any characters which are recognized
by the writer as certainly indicating its specific or generic
position, but it is evidently near Procamelus, a genus well known
in the Upper Miocene of the Great Plains and Basin regions.
The species represented by this specimen is larger than the forms
found in the Basin region, but the dimensions shown here are
approached by Procamelus robustus of the Great Plains.

MEASUREMENTS

Radius, greatest transverse diameter of distal end —.........0220..2.........- 62.5 mm.
Cannon bone, greatest transverse diameter of proximal end ........ 58.6
Scaphoid, greatest anteroposterior diameter —............-.00-00.02...0----- 38.8

GUM AT MOTCATES uel Ob gemesne st ees 2eesseceec aera eg oes eco eee ese rer ee e 31.
Magnum, greatest anteroposterior diameter — 0.00000. 34.7

PLIAUCHENTA(?), sp.

A fragment of the distal end of a cannon bone (fig. 7, no.
1982) was obtained by J. P. Buwalda at locality 707 in the
Siestan beds of Siesta Valley, in the hills immediately to the
east of Berkeley. This specimen, though very fragmentary, cer-
tainly represents a large camel approximating the dimensions
of the Recent Camelus. It evidently belongs to a form con-
siderably larger than the species from the Orindan of Bolinger
Canon and probably represents a species of the genus Pliauchenia,
a large camel of a more advanced stage of development than
Procamelus. Pliauchenia is a characteristic form of late Miocene
to Phocene time.

MEASUREMENTS
Transverse diameter of cannon bone 60 mm. above the distal end... 64. mm.
Thickness of cannon bone 60mm. above the distal end —............... 26.6
Least width of one of the two distal divisions of the cannon bone
below the: poimt Of AiMsuom 222.2222 eee ces soe seecccecece cnc ceeceensee ees ceeeesensesss 39.

TETRABELODON(?), sp.
Remains of mastodon-like forms have béen found by R. E.
Dickerson in the upper portion of the Orindan section of
Bolinger Canon, and by J. P. Buwalda in the lower portion of

382 University of California Publications in Geology (Vou. 7

the Orindan section near Tassajara Canon on the south side of
Mount Diablo. The material is all very fragmentary and is not
susceptible of even certain generic determination.

The specimen from Bolinger Canon consists of fragments of
cheek-teeth and portions of a lower jaw of an animal of con-
siderable size.

The specimens from near Tassajara Canon include fragments
of teeth. They represent an animal of the mastodon type but
the fragments are too imperfect for certain generic identification.

DIPOIDES LECONTEI (Merriam, J. C.)

From Siestan beds near Bald Peak.

The type specimen (figs. 8a to 8c), consisting of the anterior
part of a skull with three cheek-teeth on each side, was discovered
in the Siestan beds near Bald Peak. A single lower molar has

since been found in the same beds.

ay
S
S

Figs. 8a to 8c. Dipoides lecontei (Merriam, J. C). Type specimen
natural size. Fig. 8a, superior view of skull; fig. 8b, lateral view of skull;
fig. 8c, superior cheek-teeth. Siestan beds, near Bald Peak.

Figs. 9a and 9b. Dipoides, sp. Py, X 2. Fig. 9a, outer side; fig. 9b,
occlusal view. Siestan beds, near Bald Peak.

1913 | Merriam: Fauna of Orindan and Siestan 383

This form was originally described under the generic name of
Sigmogomphius, on the assumption that there were but three
superior cheek-teeth. In the original description, the writer
called attention to the similarity of the dentition to that of
Eucastor Leidy, but separated it from that genus owing to the
difference in pattern of the enamel folds. Comparative material
was not available at that time, and the writer was not aware of
the extent of change possible in the tooth pattern of these forms
with wear. There seems now good reason to beheve that a worn
Sigmogomphius molar would develop a tooth pattern similar to
that of Hucastor, and that both Sigmogomphius and Eucastor are
not to be distinguished from the Old World genus Dipoides
Jager. It is, however, worth noting that the reduction of the
posterior molars in some of these forms suggests a possible reduc-
tion of the cheek-tooth formula to three, as was assumed for the
genus Sigmogomphius. It is not certain that this reduction
occurs in Dipoides lecontei, as the last molars may have been
lost from the type specimen.

A single lower cheek-tooth, P,, (figs. 9a and 9b) from the
Siestan beds resembles the European type of Dipoides, and the
tooth pattern shows close similarity to that of a somewhat larger
form found in the Thousand Creek beds of northern Nevada.

LEPUS, sp.

Fragmentary remains of two rabbits are known from fresh-
water beds in the hills near Berkeley. They consist of a lower
tooth (no. 19827), from the Siestan beds near Bald Peak, and
a portion of a lower jaw from an Orindan exposure in Wildeat
Canon. It is doubtful whether the two specimens represent
the same species, but neither one is certainly specifically deter-

minable.
PLANT REMAINS

At several localities in the Siestan formation, imperfectly pre-
served plant remains have been found in clays and sands con-
taining fresh-water shells, a few land shells, and remains of
land vertebrates. The plant remains consist largely of fragments
of stems and leaves of rushes and grass, but include also a few

384 University of California Publications in Geology |Vou.7

leaves of trees. Professor W. L. Jepson, who has examined
these specimens, considers the leaves as representing Acer’, sp.,
Sterculia or Acer?, and Dirca, sp.

AGE OF THE ORINDAN AND SIESTAN VERTEBRATE FAUNAS

Although the vertebrate remains from the Orindan and
Siestan are probably obtained from horizons comprising quite
a wide range in time, they represent collectively the greater part
of the known land fauna of this region in a period following
the San Pablo Miocene and preceding the Pleistocene. Such
field work as has been done up to this time does not lead us to
expect large collections from these formations, though the dis-
covery of strata rich in determinable remains is always possible.
The Siestan beds seem to offer a possible fruitful field for future
collecting.

The mammalian remains known from both the Orindan and
Siestan up to the present time all represent forms such as might
be expected in the late Miocene or in the earliest Pliocene, but it
will be necessary both to have better material from the Orindan
and Siestan and to have well-known faunas of western Miocene
and Pliocene for comparison before the last word on the age
determination can be pronounced.

The late Tertiary mammalian faunas which are most avail-
able for comparison with the forms from California are those
of the Basin region, including the Tertiary beds of the Mohave
Desert region of California, those of the Cedar Mountain region
of Nevada, and the Thousand Creek beds of northern Nevada.
All of these faunas are as yet imperfectly known, but there
seems reason for considering the Thousand Creek as representing
early Pliocene, and the deposits of the Mohave and Cedar Moun-
tain regions as at least in part near late Miocene.

Compared with these faunas there seems in some respects less
suggestion of similarity with Thousand Creek than with the other
two. On the other hand, there is no indication of identity with
the so-called Mohave fauna of the Barstow region. The beds
referred to the Rosamond series, in the Ricardo region on the
western border of the Mohave Desert, contain a fauna with

1913 | Merriam: Fauna of Orindan and Siestan 385

Neohipparion, suggesting the Orindan fauna. The Ricardo fauna
is possibly somewhat later than that of the best known horizon
containing the Mohave fauna in the Barstow syncline.
Considering the indefiniteness of all the factors concerned,
one would not seem justified in being more definite than to state
that the Orindan and Siestan faunas are near a late Miocene
stage. When the faunas of the two formations are better known,

it may appear that more than one stage is represented.

Transmitted June 28, 1913.

IERSITY OF CALIFORNIA PUBLICATIONS
ei BULLETIN OF THE DEPARTMENT OF
tee ae We Sos GEOLOGY

‘ol. 7, No. 20, pp. 387-396, pls. 16-21 Issued October 31, 1913
: ae

_ RECENT OBSERVATIONS ON THE MODE OF :
~ ACCUMULATION OF THE PLEISTOCENE ‘Oe
BONE DEPOSITS OF RANCHO eo

LA BREA |

BY *
REGINALD C. STONER ae

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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 20, pp. 387-396, pls. 16-21 Issued October 31, 1913

RECENT OBSERVATIONS ON THE MODE OF
ACCUMULATION OF THE PLEISTOCENE
BONE DEPOSITS OF RANCHO
LA BREA

REGINALD C. STONER

CONTENTS

PAGE
PNET HEUER CD CHIU CC U0 Tarn ae oe ee Bee Se ume 28 Se Sa ne Sean 6a dee snedeceastsezece 387
Weseription of Localities Investigated) ....-...------c.-.<2cc--cceecccceeeceeeneceeee eee 388
Mo wallnitiyye 205 Were tne: ccc cteeet cL I cess lete cs cdc cece ces sdectescntececetseccsesccesecenseestcte 388
BNE eal tayaae (fyi Geert ee ee es eee cs a ee ence we eds secatessaenetsteceeesnitiaiesetoee= 389
BOC ality ge 2s) Aamo e cscs eee. ere see a ees ebro S22 ec2e_ coca 2 senesatdedswas-n2dhecoceucceeeens 391

General Conclusions as to the Mode of Accumulation at the Localities
JOSAH NU Pee 392

INTRODUCTION

Beginning in 1906, the University of California has collected
in the Pleistocene mammal beds at Rancho La Brea at irregular
intervals up to 1913. The Los Angeles Normal School, Los
Angeles High School, and the Southern California Academy of
Sciences have also collected a large quantity of bones from these
deposits. During the past winter the University of California
engaged in excavation work at Rancho La Brea on a much more
extensive scale than in previous years. <A careful working over
of the material found before this time indicated that certain of
the rarer animals would be obtained only by examination of a
much larger collection than had been available up to that time.

388 University of California Publications in Geology \Vou.7

These excavations were made possible through the generosity of
the late Madam Ida Hancock Ross and Mr. G. Allan Hancock,
who kindly granted a concession to work the deposits. The
work was carried on between September, 1912, and April, 1913,
under the direction of Dr. John C. Merriam and under the
immediate supervision of the writer. An average of about ten
men were employed. As our knowledge of the accumulation of
the deposits was increased somewhat by the results of these
excavations it seems desirable to record such information as

relates to origin of the bone beds. :

DESCRIPTION OF THE LOCALITIES INVESTIGATED

Locality 2050.—This locality was chosen for the first work
in 1912, as it was known that excellent material had been obtained
here in a pocket opened by Dr. L. H. Miller in excavating for
the State Normal School of Los Angeles some years ago.

The bones exposed at this point covered an area not larger
than four feet square. The larger part of the pocket was cov-
ered with ereen and brown clays. The bones found on the
surface were embedded in a hard asphalt and were very much
decayed from weathering. Two feet under the surface valuable
material in perfect state of preservation was encountered. In
the western half of the pocket the bones were embedded in a
soft, sandy asphalt, which also contained many sticks and a few
large branches of trees. In the other half of the pocket the
asphalt was mixed with green clay, which in places was filled
with coarse quartz grains. The area of bone-bearing asphalt
within two feet of the surface was small, probably about sixteen
square feet. At a depth of ten feet the area covered was about
fifty square feet. The majority of the bones were taken from
soft, sticky asphalt, and in this matrix they were the most
numerous and best preserved. Around the edge of the pocket
where clay tended to overlap the asphalt few bones were found
in the clay. In some cases where the asphalt was soft small
bones had been forced into cracks in the clay, forming veins of
bones which could be followed for two or three feet. Only a
small percentage of the total number of bones obtained came
from the fillings of these fissures. It should be noted that the

1913] Stoner: Pleistocene Bone Deposits of Rancho La Brea 389

edges of the asphalt pool were usually irregular. At some points
the deposit of clay overlapped the asphalt, at other places the
asphalt was forced into the surrounding matrix.

At a depth of from ten to twelve feet this pocket reached its
maximum area. From this depth to seventeen feet it contained
only few bones. From eight to twelve feet the floor of the
pocket was a tangled mass of bones closely pressed together and
interlocked in all possible ways. At this horizon there were
exposed at one time two horse skulls, a sloth skull, a camel skull,
and several tiger and wolf skulls, besides many other bones of
these animals.

Locality 2051'.—The largest part of the material was obtained
at this locahty in 1912. The locality as shown in plate 18
includes three separate pockets, which were completely excavated.
In pocket no. 1 the University had worked before and had taken
bones from a small hole carried to a depth of twelve feet. From
this exposure the work was extended, and two other pockets
immediately to the east were located.

The surface at locality 2051 was covered with a hard, black
asphalt, the tar having flowed out over the surface of the bones
and collected sand and clay, forming a capping for the bone
pockets. This capping contained a few bones and some vege-
table material, and varied in thickness from a few inches to four
feet. It completely covered the three bone-bearing pockets. After
the hard surface was removed, the bones were exposed in patches
as shown in plate 18. As was noted in locality 2050, the bone
pockets were relatively narrow at the top. As deeper horizons
were reached the pockets widened out, and in plate 19 the largest
horizontal section of the pockets is shown. It is interesting to
note here that the bone pockets, even at their greatest extent, are
not at any point connected. In the study of plate 20, which is
a vertical section of this locality, the three distinct bone pockets
are shown separated by the green and brown clays. The per-
sistent separation of these three pockets, which accumulated
within a short space of sixty feet and still remained distinet
from one another, may be explained by slow exudation of the
oil which did not allow the pools to overflow and unite

1 The former number of this locality was 1059.

390 University of California Publications in Geology (Vou. 7

The bones in pocket no. 1 are not so well preserved as those
in pocket no. 2. This difference in preservation is rather difficult
to explain, since they accumulated at the same time and were
only a few feet distant. From the evidence obtained a sug-
gestion may be offered. In pocket no. 1 there are large lumps
of brittle asphaltic clay scattered among the bones, and at a depth
of fourteen feet the floor of the pit was nearly covered with this
clay, veined with asphalt-bearing bones. The fact that this clay
contains globules of asphalt and also‘ has a brown color, which
is probably due to the asphalt, leads us to believe that it was
deposited in juxtaposition to the tar pools. It is safe to say
that this pool was covered with water for a considerable length
of time, allowing the deposition of clay, and so affecting the
preservation of the bones. It is quite possible also that at inter-
vals the exudation of the tar was stopped and allowed these
pools to be capped with clay. Afterward the tar again came to
the surface and another pool was formed in which bones were
deposited. In pocket no. 2 the brown lumps of clay are not
found among the bones, and there is no evidence to indicate that
water once covered this pocket.

Pocket no. 2 was the largest pocket of well-preserved bones
discovered. From within six feet of the surface to twenty-one
feet there was a solid mass of bones, the pocket varying in out-
line and narrowing toward the bottom. After the hard cover
was removed the matrix lying beneath was found to be very soft
and much tar oozed out at two or three points. Where the
tar was most abundant the bones were not so well preserved.
From a depth of ten to twenty feet the bones in this pocket were
of a light brown color and embedded in a fine sandy matrix with ,
a rather small percentage of tar.

Pocket no. 3, as may be seen in plate 20, is much smaller
than either of the others, but contained many bones in a fine
state of preservation. Here bones were found at the surface
and from this down to fourteen feet. Some of the bones obtained
at the surface were poorly preserved, yet on the east side of the
pocket sloth material was found that was of a bright red color
and the bones as hard as Recent specimens. This pocket was
quite small and therefore only parts of skeletons seemed to be

1913] Stoner: Pleistocene Bone Deposits of Rancho La Brea 391

present. Aside from the sloth material bones of large animals
were rare. Along one side of the pocket parts of many rodents,
birds and other small animals were found. These remains were
in a more sticky matrix and had probably been caught and
entombed in the tar chimney at a relatively recent date. Very
near the surface in a soft, sticky mass there were a large number
of these small bones. This pocket reached its maximum size at
eight feet, and from there to thirteen feet it narrowed down to
a small area where bones were rare.

Locality 2052.—When work was begun at this locality there
was a small mass of asphalt exposed, which contained few bones.
After clearing the surface around this exposure another pocket
was located immediately to the south. In the first pocket the
matrix was sandy, dry, and contained many twigs and small
limbs. Here the bird and rodent bones were plentiful. There
were a few horse and coyote remains, and one camel bone was
found. The dire wolf and sabre-tooth tiger were absent. In
the other pocket the bones were those of birds and rodents,
excepting a few antelope and coyote specimens. In this pocket
the bones were embedded in a sticky matrix containing little
sand and having a recent appearance. At a depth of four feet
this pocket narrowed down to a foot in width and the bones dis-
appeared. These two pockets are joined, but are united only
within a foot of the surface. The more recent exudation of oil
which took place in the second pocket flowed toward the first,
and so joined them in rather recent time. Each of the pockets
extended to a depth of four feet and there disappeared. Further
excavation showed no evidence of another pocket below. Judg-
ing from the nature of the matrix and the size of the pockets,
the bones seem to be very young, and the second pocket where
the antelope was found is possibly Recent; but the first pocket,
which has a more sandy matrix and generally a much older
aspect, is probably Pleistocene. This idea is supported by the
the finding of a camel metapodial in this area.

392 University of California Publications in Geology [Vou.7

GENERAL CONCLUSIONS AS TO THE MODE OF ACCUMULATION
AT THE LOCALITIES INVESTIGATED

The most interesting observation on the deposition of material
found in the recent excavations in the asphalt is that bones
accumulated in holes of such small size, and that the deposits
were built up to such a thickness. As seen in the section in
plate 21, the maximum depth of one pocket is at least twenty-
three feet, while the area over which it extends is comparatively
small. These pockets were not at any time depressions, twenty
to twenty-five feet deep in the Pleistocene surface, which later
filled up gradually with sand, clay and bones. From the presence
of green clay dividing pockets no. 1 and no. 2 (plate 20) it may
look as though they were filled up in this manner, but it is
obviously impossible for this wall of clay between the pockets
to have resisted ordinary rain erosion during the time in which
the pockets could receive by any natural process the enormous
mass of bones found in them. It seems quite certain that these
deposits were slowly built up along with the surrounding Pleis-
tocene formation, and that the tar pools were constantly renewing
their surfaces as the tar came out and trapped the life of that
time. Locality 2051 affords the best example of this manner of
deposition, as at this point three distinct pockets were found
in a space of sixty feet. Through all the vears that must have
been required for the building up of these asphalt masses the
exudation of the tar was so slow that the pools never joined to
form a large pool and a single large mass of bones, but remained
distinct. However slow the accumulation of the bones was, the
pools were evidently large enough to catch one or two tigers,
several wolves and an ungulate at the same time, the latter serv-
ing as prey for the carnivores. This association is quite clearly
shown in some places, and at one point in particular there were
eight wolf skulls and many wolf bones mixed with the bones and
skull of a large bison.

In all the localities investigated the quantity of bones ob-
tained was very large compared with the amount of asphalt
removed. Each pocket represented a mass of tangled bones so
closely matted that when one bone was removed there was always
another exposed. Soon after the animals were caught in the

1913] Stoner: Pleistocene Bone Deposits of Rancho La Brea 393

tar the organic tissues decayed, leaving the bones disconnected
and free to move about in the pools. Movement may have been
caused by pressure and movement of the deposits above, or prob-
ably to a greater extent by the struggling of trapped animals
and by the expulsion of the gas coming to the surface. The
continual movement of the tar while it was in a liquid state
scattered the bones of all the animals and formed a heterogeneous
mass in which the parts of many “different individuals were
mixed in all possible ways. In the center of the pocket the bones
were most numerous and so interlocked that much time was
consumed in untangling them. Toward the periphery of the
pocket the bones usually thinned out, and since they were em-
bedded in a more sandy matrix they were much more easily
extracted.

Summary.—lIn the recent excavations it is clear that the bones
occur in rather deep, narrow pits; that during the accumulation
of these deposits the different tar pools commonly remained
distinct, due to the slow exudation of the tar; that the pockets
represent a gradual accumulation built up along with the sur-
rounding Pleistocene deposits. It is further shown that a num-
ber of the pockets contained several tons of bones massed together,
representing thousands of individuals and scores of species. Since
the bones are found only in connection with the tar pools, it is
evident that their accumulation and preservation was due to the
presence of the tar.

Transmitted June 9, 1918.

EXPLANATION OF PLATE 16
General view of Locality 2051. Showing pockets 2 and 3

Photograph by J. C. Merriam “

[394].

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EXPLANATION OF PLATE 17—
Locality 2051, showing mass of bones in pocket. 20

Photograph by J. C. Merriam

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Locality 2051, Rancho La Brea

UNIV, CALIF, PUBL. BULL. DEPT, GEOL. [STONER] VOL. 7, PL. 19

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Locality 2051, Rancho La Brea

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Locality 2051, Rancho La Brea

UINIVIRCALIE: PUBL BUEE DEPT. GEOL. [STONER] VOL. 7, PL

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» 2

inc copahapeeee 3u ET IN OF THE “DEPARTMENT ¢ oF
ON ea) oC SRE OLOGY
, pp. 397-4 18, 14 text figures Issued December 16, 1913

PRELIMINARY REPORT ON THE HORSES $e
QF RANCHO LA BREA |
2 JOHN G. MERRIAM—

UNIVERSITY OF CALIFORNIA PRESS ;
ee BERKELEY k
G Veet baal oF TI ve, 2 y

ts DEC 29 ion

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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 21, pp. 397-418, 14 text figures Issued December 16, 1913

PRELIMINARY REPORT ON THE HORSES
OF RANCHO LA BREA

BY
JOHN C. MERRIAM

CONTENTS

PAGE

TEER OG OK RON aN ee ey oe eR f° (
SUEUR Ende Se 400
VD Sma EOE ee ee oe 404
@ommparison\ with Wquus caballus 22... 2.22.2 cece. ccecccesecbeecny feceeeegeenceteeceseeseesecse 412
Relationship to Pleistocene species of Western North America —........... 413
Relations tos H quus occidentalis: Wey. 2.22222 ocean cana c cent nese cen anna nee 413
Comparison with Equus pacificus Leidy ...... Seer errs ee 414

Comparison with Equus excelsus Leidy
Comparison with Equus scotti Gidley

Comparison with Equus niobrarensis Hay .................----.------------------ 416

Comparison with Equus laurentius Hay ..............----.--.-----------1--eeeeeeeees 418

SSO A EI 9h 418
INTRODUCTION

Remains of horses have been obtained in considerable
numbers from the Pleistocene beds of Rancho La Brea, but not
until within the last year has skull material been found in such
quantity as to make possible a eritical study in which the
important factors of individual and age variation could be con-
sidered with any degree of satisfaction. In the excavations
recently carried on through the kind permission of the late
Madam Hancock Ross, and her son, Mr. G. Allan Hancock, a
number of good skulls have been obtained, with much material
consisting of loose teeth and elements representing all parts of

398 University of California Publications in Geology (Vou. 7

the skeleton. These collections, together with several skulls and
much seattered material already available, offer one of the
fullest opportunities for study of American Pleistocene horses
that has been presented. Satisfactory preparation and exami-
nation of the entire series of specimens will require many months’
work. In advance of this study it is possible to give such a
statement of the most important contributions made by this
collection as will assist in the interpretation of other material.

The collection available contains eleven good skulls, several
imperfect specimens, and much fragmentary material. It repre-
sents animals of both sexes, and of all ages from foals with
unworn milk teeth to old individuals with dentition in advanced
stages of wear. The specimens show considerable variation in
the characteristics upon which our classification of American
Pleistocene horses has of necessity been largely based, and an
estimation of the significance of this variation will presumably
assist to some extent in interpretation of a number of the numer-
ous imperfectly known equine species deseribed from the Amer-
ican Pleistocene.

Up to the present time the only descriptions of satisfactory
skull material representing American Pleistocene horses are
those of Gidley’ on Equus scotti of the Texas Pleistocene, and
Hay? on Equus niobrarensis and Equus laurentius from Nebraska
and Kansas. Of Equus scotti several skulls representing indi-
viduals ranging from youth to maturity are available. Skeletal
material accompanying the skulls gives to this species a full and
satisfactory representation. Of Equus lawrentius the single good
skull known shows this form, with its slender skull and small
teeth, to be distinctly separated from the heavy-headed E. scotti
and EF. niobrarensis. Of Equus niobrarensis an imperfect skull
from Hay Springs, Nebraska, shows most of the characteristics
satisfactorily excepting the frontal and facial regions. Another
specimen from the Pleistocene of Tofty, Alaska, is referred to
a subspecies, Equus niobrarensis alaskae by Hay. The lower
jaws of this form were not found. The cranium lacks only

1 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 13, pp. 111 to 116, 1900.

2 Hay, O. P., Proc. U. S. Nat. Mus., vol. 44, pp. 576 to 591, 1913; and
Smithsonian Mise. Coll., vol. 61, no. 2, 1913.

1913 ] Merriam: Horses of Rancho La Brea 399

Figs. 1 to 3. Equus occidentalis Leidy. Skull, no. 20097, K %.
Rancho La Brea Beds, California. Fig. 1, superior view; fig. 2, lateral
view; fig. 3, inferior view.

400 University of California Publications in Geology [VoL 7

the nasal region. Equus niobrarensis is distinguished from
Equus laurentius by its shorter and wider nose, heavier and
anteriorly much higher mandible. The teeth are larger and
wider than in Equus laurentius. From Equus scotti this species
seems to be distinguished by its smaller teeth.

Before the discovery of specimens at Rancho La Brea no
good skulls and no complete skeletal specimens representing
Pleistocene horses were known from the Pacific Coast region.

SKULL

The eleven practically complete horse crania from Rancho La
Brea naturally show certain variations in form and size, but
they are so near together in the assemblage of their characters,
and present such gradations through the series, that there seems
eood reason for considering them all as one species, and they
are treated by the writer as forms of a single specific type.

The skulls from Rancho La Brea equal or exceed those of
the Recent Equus caballus in size. Compared with EF. caballus
the face is relatively a little wider, and the nose is relatively
short and wide. The notch between the nasals and premaxillaries
is wider or less acute posteriorly than in EF. caballus. In profile
the superior fronto-nasal surface is generally nearly flat, or very
slightly concave above the middle of the nasals. Between the
orbits the frontal region is in most specimens slightly more
convex transversely than in E. caballus. This seems to be true
in stages ranging from young adults to individuals of fairly
advanced age. The nasals are relatively wide, and their anterior
ends reach forward to a point a little behind the superior
canines.

The orbits are near the size of those in EL. caballus, but tend
to be shghtly larger. They are noticeably smaller than in E.
niobrarensis and E. laurentius.

The occiput is higher and narrower than in the domestic
horse, and the overhang of the inion is considerably greater. The
greatest width across the condyles averages relatively smaller
than in E. caballus.

401

1913] Merriam: Horses of Rancho La Brea

The mandible is heavy in contrast with that of the modern
horse, and the horizontal ramus is much higher below the anterior

Fig. 4. Equus occidentalis Leidy. Posterior view of skull. No. 21002,
x ¥. Rancho La Brea Beds, California.

cheek-teeth and below the diastema. The symphysial region is
relatively wide. The mandible of a specimen (no. 21000),
tentatively referred to E. occidentalis, shows unusual width

Figs. 5 and 6. Equus occidentalis Leidy(?). Mandible, no. 21000, x ¥%.
Rancho La Brea Beds, California. Fig. 5, lateral view; fig. 6, superior

view.

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404 University of California Publications in Geology [Vou.7

anteriorly. The inferior border is usually distinctly convex
below the anterior cheek-teeth, and may show a slightly concave
region below the posterior molars.

The anterior palatine foramina are situated much as in E.
caballus. In some specimens they are relatively and absolutely
shorter than in the domestic horse. The posterior palatine fora-
mina are situated near the posterior end of M? in animals of
middle age, and near the middle or anterior end of M® in old
individuals. The palatine notch of the posterior nares is oppo-
site the anterior half of M? in specimens of young adults, and
extends forward approximately to a line joining the middle
region of the second upper molars in individuals of advanced
age. In E. caballus this opening is somewhat shorter and wider,
and does not reach as far forward in the palate.

The infraorbital formamina are commonly situated in ad-
vance of the anterior end of the maxillary ridges and above
P*. In no ease do the maxillary ridges extend forward beyond
the infraorbital foramina as may occur in some forms of Equus.

The mental foramina are approximately opposite the pos-
terior end of the svmphysis.

DENTITION

The dentition is represented by a series of specimens ranging
from unworn milk teeth to those of old individuals in which the
enamel folds of the fossettes and valleys have disappeared
through wear. Variations in size and in enamel pattern of the
cheek-teeth are considerable. There is, however, such a grada-
tion in the teeth that there seems good reason for considering
all of the specimens represented as a single species.

The incisors, where observed, are large. The lower incisors
in no. 21000, an old individual, are especially wide. In none
of the specimens available does the third lower incisor show
evidence of formation of an inner fold or cup. The third upper
incisor always shows a strongly marked cup.

The canines are of moderate size compared with those of
Equus caballus. In young individuals the crown shows distinct
lateral compression.

1913 ] Merriam: Horses of Rancho La Brea 405

In teeth of corresponding position in the upper cheek-tooth
series there is considerable range in size. In general the varia-
tion falls within the limits which Gidley* has shown to hold for
modern Equus caballus. The variation in width of correspond-
ing teeth between M? and P* is commonly not more than two
millimeters in individuals of approximately the same age. In
the lower cheek-teeth there is also considerable variation in size.

As a rule the enamel pattern of the cheek-teeth is relatively
simple compared with that of other described forms (figs. 7 and
8.) In some specimens there are noticeable variations from the

Figs. 7 and 8. Equus occidentalis Leidy. Rancho La Brea Beds, Cali-
fornia. Fig. 7, superior dentition, no. 21001, X 14; fig. 8, superior denti-
tion, no. 12269, K %.

normal type of this species, but in no case is the enamel sur-
rounding the fossettes as strongly folded as in Equus pacificus.
Some of the principal variations in the pattern of the cheek-
teeth are the following: (1) form of protocone; (2) form of
post-protoconal valley; (3) position of the post-protoconal val-
ley; (4) pheation of the anterior border of prefossette and
posterior border of postfossette.

Form and size of protocone vary considerably in the Rancho
La Brea specimens. The anteroposterior diameter in M? runs
from about 11mm. in an old individual to 16mm. in a young

3 Gidley, J. W., Bull. Amer. Mus. Nat. Hist., vol. 14, p. 102, 1901.

406 University of California Publications in Geology [Vou.7

specimen. In general the protocone seems absolutely longer
anteroposteriorly and narrower transversely in young indi-
viduals. It is shortest anteroposteriorly and thickest trans-
versely in quite old individuals. Variation in stage of wear is
probably in part responsible for the location of the longest
protocone in one tooth rather than in another of the same series.
The writer does not consider that variation in size or form of
the protocone in the Rancho La Brea horses indicates the pres-
ence of more than one species.

In most specimens from Rancho La Brea the post-protoconal
valley ends anteriorly with an oblique truncation, the truncated
face beine directed forward and outward. In a number of
cases, particularly in young individuals, the enamel bordering
the anterior end of the valley shows a single indentation. The
fold is usually near the middle of the anterior end of the valley
in P*® and P?#, but is commonly situated near the outer side of
the anterior end in M' and M?*. In individuals of fairly ad-
vanced age the fold is commonly absent. In aged individuals
there is rarely a suggestion of the fold.

The position of the post-protoconal valley varies considerably
with respect to the region of the tooth margin toward which
the long axis of the valley points. In the molars the axis com-
monly points toward the inner or lngual half of the anterior
border of the tooth, in P* and P* the anterior end is usually
directed toward the outer half of the anterior side of the tooth.
The position in P* and P* is referred to as erect, that in the
molars as depressed. The difference in position is frequently
related in part to difference in form of the protocone.

The anterior and posterior fossettes of the molars and pre-
molars have in general relatively simple enamel borders com-
pared with most Pleistocene horses of North America. There
is quite uniformly a single clearly defined fold in the middle of
the anterior side of the postfossette and one on the posterior
inner region of the prefossette. A few minor wrinkles may also
be present near the major folds just mentioned. On the an-
terior side of the prefossette there is often a single weak fold
or indentation. This fold is usually strongest on the premolars
and on M?, though it may be present on the other molars. The

1913] Merriam: Horses of Rancho La Brea 407

anterior fold is generally absent in advanced stages of wear.
On an individual with M* just coming into function it is absent
or barely indicated on M'! and M?, but is distinctly shown on

Figs. 9 and 10. Equus occidentalis Leidy. Mandible with dentition,
no. 12269, X ¥%. Rancho La Brea Beds, California. Fig. 9, lateral view;
fig. 10, superior view.

Fig. 11. Equus occidentalis Leidy. Mandible with dentition, no.
21002, X ¥%. Rancho La Brea Beds, California.

the last two premolars. On the posterior fossette a posterior
indentation or fold is commonly present in young animals, but

408 University of California Publications in Geology [Vou.7

may be poorly developed. It is often most distinct on the pre-
molars. Both the anterior fold of the prefossette and the pos-
terior fold of the postfossette may, in rare cases, be accompanied
by a few minor wrinkles.

In the upper cheek-teeth the external ribs formed by para-
style, mesostyle, and metastyle are very strong, but even in old
individuals the mesostyle of the molars shows somewhat less
flattening externally than in E. caballus.

The lower cheek-teeth (figs. 5, 6, 9, 10, 11) do not differ
ereatly from those of EF. caballus. Compared with specimens
of the domestic horse available, the Rancho La Brea form seems
to have relatively narrower lower premolars, but measurements
of other specimens of modern horses seem to indicate that this
character may not show a constant difference. In the pre-
molars the outer enamel fold between the protoconid and hypo-
conid is not produced between the anteroposterior folds
separating the metaconid and metastylid from the protoconid
and hypoconid. In the molars the inner end of the outer fold
may .extend between the two anteroposterior folds. Particularly
in young specimens there may be a tendency to form a small
secondary fold on the posterior side of the outer fold between
protoconid and hypoconid. In some eases the anterior end
of the anteroposterior fold between metastylid and hypoconid
may show an indentation (fig. 6), and the enamel wall on the
inner side of the hypoconid may show a slight erinkling. The
groove between the metaconid and metastylid columns is well
marked but wide. In general the characters of the lower teeth
seem close to those of FH. niobrarensis.

The milk dentition is well shown in several specimens. In
the upper milk molars (fig. 13), the post-protoconal valley
shows a light terminal indentation in specimen 20099, in which
M?' is just pushing through the jaw. In no. 19834, a slightly
older specimen, the terminal indentation of the post-protoconal
valley has almost disappeared. There is a single indentation
at the anterior end of the anterior fossette, and one at the pos-
terior end of the posterior fossette, in each of the cheek-teeth
in both no. 20099 and no. 19834.

1913] Merriam: Horses of Rancho La Brea 409

In the lower milk molars (fig. 14), the outer fold between
the protoconid and hypoconid pushes farther in toward the
middle of the tooth than in the permanent premolars. The
small fold or jog on the posterior side of this outer fold is well
marked. The small fold on the antero-external angle of Dm, is
well shown.

Figs. 12 and 13. Equus occidentalis Leidy. Superior milk dentition,
no. 20099, X 4%. Rancho La Brea Beds, California. Fig. 12, temporary
incisors; fig. 18, temporary molars.

Fig. 14. Equus occidentalis Leidy. Inferior temporary molars, no.
21072, K %. Rancho La Brea Beds, California.

MEASUREMENTS OF DENTITION

Measurements of all cheek-teeth are made exclusive of the cement.

In the upper dentition, excepting in P? and M3, the anteroposterior
diameter is measured along the middle of each tooth, between the principal
anterior and posterior faces of contact with the adjoining teeth. In P2
and M3 the anteroposterior diameter is measured from the middle of the
face of contact with the adjoining tooth to the extreme opposite limit of
the tooth. In P3 to M2 the anteroposterior diameter does not include the
anterior projection of the parastyle in advanee of the principal anterior
contact plane of the tooth. Transverse diameters are measured across
from mesostyle to the innermost extent of the protocone.

In the lower cheek-teeth the anteroposterior diameter is measured as in
the superior series, and includes the limits measured along the middle of
the tooth. The transverse diameter of the lower cheek-teeth is the greatest
diameter measured across the protoconid and metaconid excepting in P,.
In P, the transverse measurement is across hypoconid and entoconid.

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412 University of California Publications in Geology [Vou.7

MEASUREMENTS* OF MILK DENTITION

No. No. No. No.

20099a@ 19834b 21072c 19835d
Dm’, anteroposterior diameter .............. (OTM, acces, ceases eee
Dm’, anteroposterior diameter: . 50 48 9
Dm’, transverse diameter ...............------- 24.6 248 cancsset, Nees
Dm’, anteroposterior diameter .............. 34 33), . Sebcis Pee
Dm*, transverse diameter ..........0000.-.--- 2 26:00 =) eee
Dm‘, anteroposterior diameter .............. 38 36:2 as eee
Dm‘, transverse diameter ...................... 24.5 2612 48 ee
Di’, greatest transverse diameter ........ 2290 ote are eee
Di’, greatest transverse diameter ........ 228; ciedessoll 9) teas ees
Di’, greatest transverse diameter ........ Q's: eel ene eee
Dm,, anteroposterior diameter -......00-.00 cence cee 40 39.8
Dm., transverse diameter ...... ee | ae aeey 14.2 14.8
Dm, anteroposterior diameter -.......0.22.0 cece eee 34. 34.9
Wm... tramsyverse) dvameter wesc eee eens eeeeaees 14.5 16.2
Dm,, anteroposterior diameter .......0:-- 0 cece cence 37.2 34.6
my, tmamsverse diamiet ery cece. esses nesses esses 12.9 15.9
Di,, greatest transverse diameter 2... ec, cece neta 17.8
Di,, greatest transverse diameter 00. 0-22. 0 ceceeoee 18.3
Di;, greatest transverse diameter 00... 0 2-2 000 eeeeeoee 14.5

* Measurements taken in manner indicated in discussion on page 409.
a, M* just emerging through jaw.

b, M* erupting.

c, M, showing first traces of wear.

d, M,in function, M, erupting.

COMPARISON WITH EQUUS CABALLUS

The skulls of Rancho La Brea horses have approximately
the size seen in the modern domesticated horse, but range up-
ward to dimensions greater than those of the average domesti-
cated horse. They differ from Equus caballus in the shorter
and wider nose, more convex forehead, narrower occiput, and
more massive lower jaw. The mandible is very noticably higher
below the premolars and the diastema.

The dentition of the Rancho La Brea species differs from
that of Equus caballus in the more simple pattern of the enamel
of the cheek-teeth. The dimensions do not differ markedly.

1913] Merriam: Horses of Rancho La Brea 413

RELATIONSHIP TO PLEISTOCENE SPECIES OF WESTERN
NORTH AMERICA

In comparing the Rancho La Brea horses with the known
Pleistocene species of America considerable difficulty is en-
countered, as the larger number of described forms are based
upon very scanty material, usually cheek-teeth alone. Only
three North American Pleistocene horses are known by skulls,
and of these only Equus scotti is represented by more than one
specimen. Of Equus laurentius there is one good skull, of typical
Equus niobrarensis one specimen with imperfect facial and
frontal region. It is probable that several of the American
species of Hquus which are considered distinct run near each
other in skull characters, and until the approximate limits of
variation are known in each, it will be difficult to make certain
of specific distinctions.

Until the appearance of the important papers by Gidley*
on Equus scotti, and Hay® on Equus lawrentius and Equus nio-
brarensis, specific separation of American Pleistocene horses was
based almost entirely upon characters of the cheek-teeth, and in
a considerable number of species but little material was known.
As has been shown by Gidley, horse teeth of the same stage of
growth may vary markedly in size and pattern, and where
various stages of wear are compared the range of difference is
wide. As first noted by Gidley, the character of size, particu-
larly as seen in the transverse diameter, of the cheek-teeth seems
the most reliable.

While it is doubtless true that good specifie differences appear
in the enamel pattern of the cheek-teeth, it is certain that such
characters must be used with caution. The final determination
of the value of these characters must depend upon examination
of considerable series of individuals of nearly the same age.

Relation to Equus occidentalis Leidy—Typieal horses of the
genus Equus have been known fossil from California in two
species represented by very fragmentary remains. The first
form described, Equus occidentalis Leidy,’ was based upon a

4 Gidley, J. W., Bull. Amer. Mus. Nat. Hist., vol. 13, art. 13, 1900.

5 Hay, O. P., Proc. U. 8. Nat. Mus., vol. 44 (no. 1969), 1913.
6 Leidy, J., Proc. Acad. Nat. Se. Philad., 1865, p. 94.

414 University of California Publications in Geology [Vou.7

specimen found in Pleistocene auriferous gravels at a depth of
thirty feet below the surface in Tuolumne County, California.
Better material from an asphalt bed near Buena Vista Lake in
the southern end of the Great Valley of California was after-
ward referred to this species by Leidy’. The second species,
Equus pacificus Leidy®, was based upon an upper premolar tooth
from Martinez, California. Gidley® recognizes this species as
the common horse of the Pleistocene at Fossil Lake, Oregon.
These two species have come to be well known in palaeontologic
literature as representing the Pacific Coast horses, though rela-
tively meagre information has been available coneerning both
forms.

The cheek-teeth from Tuolumne County, California, consti-
tuting Leidy’s type of Equus occidentalis agree very closely in
dimension and in enamel pattern with average specimens from
Rancho La Brea. Considering that the typical. Equus occi-
dentalis occurs in approximately the same geographic region as
the asphalt forms, there seems every reason to believe that the
common horses from Rancho La Brea represent Equus occi-
dentalis. The material from near Buena Vista Lake in the
southern end of the Great Valley of California, which Leidy
referred to Equus occidentalis, seems quite certainly to repre-
sent the same species as the specimens from Rancho La Brea.

In the table of measurements on p. 410, the dimension of
Rancho La Brea specimens are shown in comparison with those
of the type of Equus occidentalis.

Comparison with Equus pacificus Leidy.—The relation of the
Rancho La Brea horses to the type described from Martinez,
California under the name of Equus pacificus is not so easily
determined as is their affinity to E. occidentalis. The type of E.
pacificus as described by Leidy consisted of a single upper pre-
molar three, which was not figured. The enamel is described as
less simple than in the horses of the group referred to E. occi-
dentalis of California, and there was stated to be an inflection

7Leidy, J., Extinct Mammalia of Dakota and Nebraska, p. 267, 1869.
Also Geol. Surv. Terrs., vol. 1, p. 242, pl. 33, fig. 1, 1873.

8 Leidy, J., Proc. Acad. Nat. Se. Philad., 1868, p. 195.
9 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 14, p. 116, 1901.

1913] Merriam: Horses of Rancho La Brea 415

of the enamel at the anterior end of the post-protoconal valley.
The tooth was characterized especially by its large size. The
dimensions are compared with those of E. occidentalis in the
table on p. 410. As is seen in the table of measurements, the
largest specimens from Rancho La Brea approach the type of
E. pacificus in dimensions. They are, however, quite different
in average pattern of the enamel. Even the largest speci-
mens from Rancho La Brea fall below the dimensions of Leidy’s
type of EF. pacificus, and below Gidley’s typical material from
Fossil Lake. It is very doubtful whether any of the Rancho
La Brea specimens thus far examined ean be referred to E.
pacificus. It is evident that the typical horses of Rancho La
Brea are EF. occidentalis.

Comparison with Equus excelsus Leidy—The Great Plains
species described as Equus excelsus by Leidy in 1858, from ma-
terial obtained in Nebraska, approaches the California EF. occiden-
talis very closely. In reviewing the species in 1869 Leidy'® stated
that there was little doubt that EH. excelsus and E. occidentalis
were the same, and he united the two. In 1873 Leidy"! referred
to the two under the name of E. occidentalis. As pointed out
by Gidley!” the name E. excelsus really preceedes E. occidentalis.
Gidley suggests that the Nebraska form shows a tendency to
more complicated enamel pattern of the cheek-teeth, and that it
may be a relatively simple variation of a form normally with a
much more complicated pattern than the typically simple teeth
of the California EH. occidentalis. Gidley also calls attention to
the fact that H. excelsus and E. occidentalis were described from
geographic stations widely separated, on opposite sides of the
Rocky Mountain system. After weighing the evidence available,
Gidley held it wisest to consider the two species as distinct.

Recently Hay'® has referred to E. excelsus additional mate-
rial, and has discussed the relation of the species to EF. niobra-
rensis.

10 Leidy, J., Extinct Mammalian Fauna of Dakota and Nebraska, p.
267, 1869.

11 Leidy, J., Geol. Surv. Terrs., vol. 1, p. 248, 1873.
12 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 14, p. 115, 1901.
13 Hay, O. P., Proce. U. S. Nat. Mus., vol. 44 (no. 1969), p. 592, 1913.

416 University of California Publications in Geology [Vou.7

With only meagre material representing the cheek-tooth
dentition at hand, it seems futile to attempt to establish definitely
the relationship of HF. excelsus to the California E. occidentalis.
It is certainly necessary to have a larger series of teeth, and it
will probably be necessary to have good skull material before a
satisfactory comparison can be made.

A character of the type of E. ercelsus to which both Gidley
and Hay have called attention is the position of the postpalatine
foramina, which are unusually far forward, opposite the anterior
half of M*. In the Rancho La Brea skulls the postpalatine fora-
mina range from a position opposite the middle of M® in individ-
uals of advanced age to a position opposite the posterior half of
M? in individuals of middle age with all of the molars in function.
The type of E. exrcelsus represents a young adult with M?
sufficiently worn to show the enamel pattern clearly. It is pos-
sible that the somewhat advanced position in the California form
may be indicative of relationship to EF. excelsus.

Comparison with Equus scottt Gidley—Of the American
Pleistocene horses known up to the present time Equus scott,
described by Gidley™, is the only form represented by more
than a single skull. Unfortunately only one of several skulls
obtained up to the time of Gidley’s revision of the Pleistocene
horses in 1901 was that of an adult in which all of the teeth had
come into full use. The Rancho La Brea horses resemble E.
scotti in being a large-headed form. They differ from E. scotti
in the somewhat smaller cheek-teeth, less pronounced enamel
folds around the fossettes and at the anterior end of the post-
protoconal valley of the cheek-teeth, and possibly also in possess-
ing a shorter and wider nose. Other differences will doubtless
appear when the two species can be more fully compared.

Comparison with Equus niobrarensis Hay.—Hay’s recently
deseribed species, Hquus niobrarensis”, from Hay Springs,
Nebraska, approaches the Rancho La Brea form closely in char-
acters of skull and dentition. Both types have a heavy, short
head, a heavy mandible, and a short, wide nose. The Rancho
La Brea species differs slightly from F. niobrarensis in the

14 Gidley, J. W., Bull. Am. Mus. Nat. Hist., vol. 13, p. 111, 1900.
15 Hay, O. P., Proce. U. 8. Nat. Mus., vol. 44 (no. 1969),.p. 576, 1913.

1913 | Merriam: Horses of Rancho La Brea 417

shortness and width of nose, relative narrowness across the skull
through the anterior region of the maxillary ridges, relative
narrowness in superior view immediately in front of the inion,
and smaller size of the orbits. The postpalatine foramina and
the anterior end of the inferior nasal opening are somewhat
farther forward in some specimens than in FE. niobrarensis.

The cheek-teeth of the Rancho La Brea form are slightly
larger than in FE. niobrarensis, and the tooth row is in most
specimens relatively longer. The relation of the tooth row to
the basilar length in the type of EF. mobrarensis is 33.8%. In
no. 21002, a much older specimen, from Rancho La Brea, the
proportion is 34.9%. In no. 20098 it is 36%.

As shown in the table of measurements on page 410, the
average width of the cheek-teeth of the Great Plains form is
somewhat less than in the average of the Rancho La Brea speci-
mens. Unless the difference can be shown to hold for a large
number of individuals it would hardly be considered of specific
value. Between E. niobrarensis and the Rancho La Brea form
there are certain small differences in the pattern of the enamel.
In E. niobrarensis the folding of the enamel at the anterior and
posterior borders of the fossettes, and at the anterior end of
the post-protoconal valley is more pronounced, and in that
species the anterior end of the post-protoconal valley is wider.

The relation of E. niobrarensis to the Rancho La Brea horses
suggests a resemblance of the former species to E. e.xrcelsus.
E. excelsus 18 apparently somewhat nearer to E. niobrarensis
than is the California E. occidentalis. In a recent paper Hay'
has discussed the relationships of FE. niobrarensis and E. excelsus,
and considers them distinct. In Hay’s paper a series of cheek-
teeth referred to E. exrcelsus seems partly to bridge the gap
between these two species, but other characters may still separate
them.

The California E. occidentalis appears to be separable from
E. niobrarensis by more simple pattern of the enamel of the
cheek-teeth, and by several skull characters, no one of which
seems, however, entirely reliable with the material available.
The presumption is that these species are distinet, but it is

16 Hay, O. P., Proc. U. S. Nat. Mus., vol. 44 (no. 1969), p. 592, 1913.

418 University of Califorma Publications in Geology [Vou

very desirable to have more material of H. niobrarensis for a
fully: satisfactory comparison.

Comparison with Equus laurentius Hay.—A fine skull from
supposed Pleistocene near Lawrence, Kansas, recently described
by Hay,’ and designated as the type of a new species, Equus
lawrentius, represents a form quite different from the California
E. occidentalis. The skull and teeth in EZ. laurentius are much
smaller; the nose is relatively longer and narrower; the width
behind the orbits is relatively greater; the mandible is much
more slender, being narrower or lower below the premolars; the
inferior border of the mandible is straight instead of sinuous
as in E. occidentalis; the orbits seem to be relatively larger.

SUMMARY

The species of horse commonly represented in the Pleistocene
beds of Rancho La Brea is not separable from Equus occidentalis
first described by Leidy from Tuolumne County, California.

As represented by the excellent series of specimens from
Rancho La Brea, Equus occidentalis is characterized by its large,
heavy head, short and broad nose, high and heavy mandible,
and relatively simple enamel pattern of the cheek-teeth.

17 Hay, O. P., Proc. U. 8S. Nat. Mus., vol. 44 (no. 1969), p. 584, 1913.

Transmitted September 18, 1913.

E seen it oF

ae, Issued December 16, 1913

JOHN C. MERRIAM

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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 22, pp. 419-434, 5 text figures Issued December 16, 1913

NEW ANCHITHERIINE HORSES
FROM THE TERTIARY
OF THE GREAT BASIN AREA

BY
JOHN C. MERRIAM

CONTENTS

PAGE

TE ales COX AUCH 0 ee ee 419
Hypohippus (Drymohippus) nevadensis, n. sub-gen. and n. sp. ...........-.. 420
Soul em GD STG GY OME ee coec ctw es oot cs cactacs cee secee ace seed cdueueetecesecec cases soeceueceuivecoets 420

J EAU TN OS el eee Oe en es eae 425

A RKCUET RO HOES OUT 0} ee ey er ec re ee eee 426
Parahippus(?) mourningi, n. sp. -......./ See ee et 427
Wippery@heek Veet Wee. set eyst acre eee hase scseevegen de secescccesedeecucestees:seneses use Seeescces 428

TU Coy Sher (ON AVEYED ETE 4a lng er Er 430
TSH OWS) GT OFS) gener rere rr OF Soe et cea ee ere 432

INTRODUCTION

Within the past two years, four expeditions from the Univer-
sity of California have visited the southern portion of the Great
Basin region to search for vertebrate remains in Tertiary
deposits. One party investigated the region southeast of Walker
Lake, Nevada, in 1912, and three parties have worked in the
Mohave Desert area in 1911, 1912, and 1913.

Of numerous palaeontologic contributions made by these
expeditions, among the most interesting is the discovery of two
anchitheriine horses presenting phases of structure or stages of
development not previously known in the groups with which
they are most nearly allied.

420 Umversity of Califorma Publications in Geology (Vou.7

The first specimen found was obtained by Lawrence C.
Baker in the Mohave Miocene of California in April, 1911. It
represents the lower jaw of a form showing characters near
those of both Parahippus and Archaeohippus. A fragmentary
upper jaw, evidently belonging to an animal of the same species
as that found by Mr. Baker, was discovered in the Mohave Beds
by J. P. Buwalda and H. C. Mourning in January, 1913.

The second type of anchitheriine horse discovered is repre-
sented by a slab containing scattered parts of a skeleton obtained
in the region southeast of Walker Lake, Nevada, by Baker
and Buwalda in May, 1912. This specimen had previously been
seen by Mr. T. H. Buck of Mina, Nevada. It was through the
kindness of Mr. Buck that the slab was pointed out to Baker
and Buwalda. The writer wishes to express his thanks for the
kind assistance given by Mr. Buck in bringing the specimen to
the railway station for shipment.

HYPOHIPPUS (DRYMOHIPPUS!1) NEVADENSIS, n. sub-gen. and n. sp.

Type specimen no, 21056, University of California Collections in Verte-
brate Palaeontology. From the Stewart Valley Miocene, twenty-four
miles northeast of Mina, Nevada.

Characters much as in Hypohippus, but metaloph of milk molars not
connected with ectoloph.

The type specimen consists of 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. The elements of
the limbs were in part connected.

Skull and Dentition—The greater portion of the skull had
been weathered away before the specimen was discovered. All
that remains consists of a portion of the lower region of the
cranium. Fortunately it was embedded in such a manner that it
faced into the rock, and only the roots of the teeth were damaged.
The portions of the cranium present show little of significance.

The dentition (figs. la and 1b) shows three well-preserved
cheek-teeth. The incisors are not present. The cheek-teeth rep-
resent the milk dentition with Dm* just coming into function.
They are referred to the milk dentition as they are relatively
narrower than P? to P* of nearly related forms.

1 Spuuds, wooded dell or glade; ‘ir7os, horse.

1913] Merriam: New Anchitheriine Horses 421

The teeth of no. 21056 represent an animal larger than any
of the known forms of Hypohippus, but approaching in size
Hypohippus affinis, the largest described species. They are
absolutely larger than the permanent premolars of H. osborni,
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.

COMPARATIVE MEASUREMENTS OF DENTITION

Milk dentition Permanent dentition
a
H. nevad- H. affinis
ensis Type H. lal
. No. 21056 specimen osborni equinus
Dm’, anteroposterior diameter along
OUbeT ORG CL eeesecerseese sees ceeeeaese Bye) | dba eee P22 fea" 25
Dm’, greatest transverse diameter. 29 —........ PP? 26 25
Dm‘, anteroposterior diameter along
Ouberab On deri eesseeee coerce Bilge? ga e952 5:4 25
Dm‘, anteroposterior diameter meas-
ured through protoconule and
1A 7 0X0) (C2) eee ee 20 aie P? 24 22 b
Dm’, greatest transverse diameter. 30.5 — ....... P? 30 27
Dm‘, anteroposterior diameter along
OULET Onder geccecesrsee eeececsseeeeeeseses 31.9 ap. 28.5 ap. P* 30 25

Dm‘, anteroposterior diameter meas-

ured through protoconule and

InyPOstyley ses eieess ceectessees cece ‘ere 26.7 a Pt 25 22 b
Dim‘, greatest transverse diameter. 31.4 29 Pt 30 26

a, measurements from J. Leidy’s figure of type specimen.
b, from W. B. Scott’s figures of type specimen.
ap, approximate.

In form and pattern of the milk molars the Nevada specimen
resembles in general the permanent dentition of Hypohippus
osborm. The protoconule portion of the protoloph seems a little
more distinctly marked off from the protoecone in Dm? than in
P? of H. osborni. In Dm*, however, the protoconule region of
no. 21056 seems less distinct than in P* of H. osborni. In Dm?
of no. 21056 the longitudinal ridge or rib on the outer side of
the paracone is much less distinct and the parastyle is more
prominent than in P? of H. osborni. A small but distinet hypo-
style is seen on Dm? and Dm*. The size of the hypostyle is near
that in the premolars of H. osborm. On Dm? there is a strong

422 University of Califorma Publications in Geology [Vou 7

shelf of the cingulum extending around the anterior and inner
sides and into the hypostyle region posteriorly. On Dm* the
cingulum is faintly interrupted on the inner side opposite the
middle of the protocone, and fully interrupted on the inner side
of the hypocone.

‘a
y, a} mu
Veit ee Bea

pO eZ Zi) NS U7 SiG, ~ >.
fae) sso Ib 2)

Figs. la and 1b. Hypohippus (Drymohippus) nevadensis, n. sub-gen.

and n.sp. Upper milk molars. No. 21056, natural size. Fig. la, lateral
view; fig. 1b, occlusal view. Stewart Valley Beds, southwestern Nevada.

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 ectoloph. 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 metaloph barely reaches the base of the
ectoloph. In Dm+‘ the base of the metaloph scarcely reaches the
base of the ectoloph. 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

1913 | Merriam: New Anchitheriine Horses 423

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 con-
sists of two small tooth-like projections. On the longer or lower
of these points the diameter, parallel with the 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 projec-
tion does not reach the bottom of the valley between metaloph
and metacone crescent. On Dm* the inner transverse prominence
of the ectoloph is very small, and is situated near the crest of
the ectoloph. On Dm? the prominence is higher, but is reduced
rapidly at the proximal end and does not connect with the
metaloph.

A certain significance may attach to the situation of the inner
transverse ridge of the ectoloph. In the milk teeth of the
Nevada form, this transverse crest or ridge rests upon the pos-
terior end of the paracone crescent. In a permanent upper
molar (no. 11570) of Hypohippus from the Middle Miocene of
Virgin Valley, Nevada, the connection between metaloph and
ectoloph is established at the posterior end of the paracone
crescent. In the cheek-teeth from P? to M* in H. osborni the
inner transverse ridge of the ectoloph arises almost exactly at
the junction of the paracone and metacone crescents. In no.
12564, a very narrow Hypohippus tooth from the Virgin Valley
Miocene of northern Nevada, the union of metaloph and ectoloph
seems to be as in AH. osbornmi. In the original reference to tooth
no. 12564 the writer suggested? that this form might represent
a species distinet from no. 11570, which is much wider antero-
posteriorly and shows the more anterior position of the inner
transverse ridge of the ectoloph.

2 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, pp. 259 and
260, 1911.

424 University of California Publications in Geology [Vou.7

The separation of metaloph and ectoloph as noted in the milk
teeth of specimen no. 21056 is a matter of considerable interest
in the classification of the Equidae. In Mesohippus the metaloph
and ectoloph are separate, and a small transverse ridge ‘or
wrinkle may arise from the inner side of the ectoloph in the same
situation as that in the milk teeth of the Nevada specimen, no.
21056. In Miohippus, as represented by specimens from the John
Day series, the metaloph is usually separated from the ectoloph.
In Anchitherium, Hypohippus, and Archaeohippus the metaloph
is completely united with the ectoloph. The stage of advance
of the cheek-teeth in the Nevada specimen, no. 21056, is near
that of Miohippus so far as the relation of the metaloph to the
ectoloph is concerned, and in this character it differs from the
known forms of Anchitherium, Archaeohippus, and Hypohippus.
In general form of the cheek-teeth and in the relation of pro-
tocone to protoconule, specimen no. 21056 is of the Hypohippus
type. In Mesohippus, Miohippus, Archaeohippus, and Anchi-
therium, the protocone and protoconule are distinctly separated,
in Hypohippus and in the Nevada specimen the protoconule is
small, and is almost completely merged with the protocone.

As the teeth in specimen no. 21056 correspond so closely to
the general type of cheek-teeth in Hypohippus, the hypothesis
that the milk molars of typical Hypohippus might show the
primitive character of the Nevada specimen naturally suggested
itself. Leidy’s type of Hypohippus affinis, the typical species
of that genus, is a milk tooth, but the specimen shows no sug-
gestion of separation of metaloph and ectoloph. It is shghtly
worn, but a corresponding degree of wear in Dm* of the Nevada
form would not tend in any way to connect metaloph and
ectoloph. Dr. W. D. Matthew, who has very kindly examined
such milk teeth of Hypohippus as are present in the ‘collections
of the American Museum of Natural History, finds that in all of
the specimens the metaloph and ectoloph are connected.

The Nevada form represented by specimen 21056 seems,
therefore, to represent 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.

1913 | Merriam: New Anchithertine Horses 425

Limbs.—Portions of both the anterior and posterior limbs
(figs. 2a and 2b) exhibit some of the essential characters, but
parts of each of the feet had been carried away before burial,
or had been destroyed by weathering before the specimen was
found. The general character and proportions of the parts of
the extremities preserved are near those of Hypohippus. The

Figs. 2a, 2b, and other fragments. Hypohippus (Drymohippus) nevad-
ensis, n. Sub-gen, and n.sp. Portions of limbs. No. 21056, K ¥%. Fig. 2a,
anterior limb; fig. 2b, posterior limb. Stewart Valley Beds, southwestern
Nevada.

426 University of California Publications in Geology [Vou.7

lateral digits and their ungual phalanges are relatively large,
and were evidently functional. The first and second phlanges of
the median digit are relatively shorter 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. Metacarpal
three shows a distinetly oblique lateral facet for articulation
with the unciform. In metatarsal three there seems to be a very
small and quite oblique facet for the cuboid. In general the
limb structure resembles that of Hypohippus.

MEASUREMENTS OF LIMB ELEMENTS

Radius, oreatest leneth ot \shavtt, Seeteescesccee ees seeeweeseeesaeeeseenteeeeeeeneas 241 mm.
MAIGbNey, ICN RH ayalcliddy Ge Sel ane A ee eee 25
Metacarpall Mil woreatest. Lem eth. sccesescereter. ore ceteet ee eeeesese ase eee 190
Metacarpall Til; soreatest: lem pithy 222. sscecccecescetessezscsceeescesceesesesseeaqes 192
Metacarpal III, width of distal end, approximate ....................-- 28.5
Phalanx J, digit III of anterior extremity, greatest length........ 4¢
Phalanx 1, digit IIT of anterior extremity, greatest width.......... 30
Phalanx II, digit IIT of anterior extremity, greatest length...... 30
Phalanx II, digit LIT of anterior extremity, greatest width........ 31
Mictanarsall 1b woneabestel riot leseems esses seesveers se oeeeee eee eee 2038.
Metatarsal IV, greatest width at proximal end —.....000222....--- aT
Phalanx I, lateral digit (hind foot?) greatest length along

SUP CRN O Pes 2s ee asa a serve eee cere cee ee ee 23.5
Phalanx IIT, lateral digit (hind foot?) length along superior

SCLC ccs s aS ee RR area SO 35

Relationships.—The form represented by the Nevada speci-
men, no. 21056, resembles Hypohippus in the characters’ of the
limbs and in the general form of the cheek-teeth. It differs from
Hypohippus in the separation of metaloph and ectoloph in the
milk dentition. It is uncertain whether the permanent dentition
of this species is represented in any of the collections from the
Great Basin region. <A difference in tooth characters comparable
to that separating this species from typical Hypohippus is
ordinarily considered as of generic value. In this particular
case, 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 is not

1913 | Merriam: New Anchithertine Horses 427

clearly distinguished from that genus. Viewed from the most.
unfavorable angle, the gap between this form and typical Hypo-
hippus seems less than the spaces between other anechitheriine
genera. The writer has therefore tentatively included this species
in the Hypohippus group, with the suggestion of incipient
separation indicated in the subgeneric distinction. The new sub-
genus, Drymohippus, proposed to inelude 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.

PARAHIPPUS(?) MOURNINGI,3 n. sp.

Type specimen no. 19840, a portion of a maxillary with milk dentition
and Mt. Paratype, a portion of a mandible, no. 19764, with dentition
representing , to M.. Both specimens from the Mohave Miocene, Mohave
Desert, California.

A portion of a lower jaw with dentition (figs. 5a and 5b)
obtained by Mr. Baker in 1911 was recognized by the writer as
representing a horse with characters near Parahippus and Hypo-
hippus, but with size and stage of evolution suggesting Archaeo-
hippus. The specimen differed, however, from the only lower
jaw material referred to Archaeohippus in several characters,
and especially in the absence of the strong internal cingulum
shown on teeth referred to Archaeohippus by Gidley.t. In
January, 1913, a second specimen, a maxillary (fig. 3) with Dm®*
Dm?, and M’, representing a very small brachyodont horse, was
obtained in the Mohave region by Buwalda and Mourning, and
again the resemblance to the genera Parahippus, Hypohippus,
and Archacohippus appeared. An approximation of the dimen-
sions of the cheek-tooth series, as well as a comparison of
individual teeth, shows that the upper and lower jaw specimens
represent animals of very nearly the same size. The simi-
larity of dimensions, considered with similarity of relationship
to other forms and similarity of occurrence, leaves little room

3 This species is named in honor of Mr. H. 8S. Mourning, through whom
the first specimens from the Mohave region came into the writer’s hands.

1 Gidley, J. W., Bull. Amer. Mus. Nat. Hist., vol. 22, p. 385, 1906.

428 University of California Publications in Geology |Vou.7

for doubt that the two jaws represent the same species.

The species represented by specimens 19840 and 19764 seems
distinct from any form thus far described. In spite of its frag-
mentary nature, the upper jaw specimen is selected as the type,
as the characters of the superior cheek-tooth series seem more
significant in discussion of the relationships. ;

Upper Cheek-teeth—In the specimen representing the upper
jaw (fig. 3), the well-preserved, unworn, inner portion of M?*
offers good opportunity for examination of certain’ distinctive
characters of this form. In this tooth the metaloph is fully
united with the ectoloph. The protoconule is distinctly separate
from the protocone, it is considerably elongated and flattened,

Fig. 3. Parahippus(?) mourningi, n. sp. Dm*, Dm*, and M*. No. 19840,
x 1%. Mohave Miocene, Barstow Syncline, Mohave Desert, California.

Fig. 4. Archaeohippus ultimus (Cope). Upper molar. No. 1689, & 114.
Middle Miocene, Maseall Beds, Eastern Oregon.

and its inner end slightly overlaps the protocone. The hypostyle
is larger than in Hypohippus and Archaeohippus, and there is
a more distinet cup-like depression behind it. There is no sug-
gestion of a crochet, though several plate-like projections arise
from the anterior side of the outer emgl of the metaloph. The
cingulum is well developed on the posterior side, and less dis-
tinctly on the anterior side between protocone and protoconule.
There is no shelf of the cingulum on the inner or lingual side
of the tooth. The cusps or ridges of the crown are somewhat
higher than in Archaeohippus or in Hypohippus. The surface
shows a degree of rugosity more pronounced than seems char-
acteristic of Hypohippus or of Archaeohippus. No trace of

cement is evident upon the crown.

1913] Merriam: New Anchitheriine Horses 429

The crowns of the milk molars of the Mohave specimen were
apparently somewhat shorter and slightly rougher than those
of the permanent molars. As in the permanent dentition, the
milk molars show the metaloph connected with the ectoloph,
there is no internal or lingual shelf of the cingulum, and the
hypostyle is large. On one of the milk molars there is a faint
suggestion of erinkling of the anterior side of the outer end of
the metaloph. A P?* from the Mascall Miocene considered by
Gidley to represent Archaeohippus differs from the milk molars
of the Mohave specimen in showing much greater development
of the longitudinal ribs on the outer side of the paracone and
metacone. There is a very faint longitudinal rib on the outer
face of the paracone in Dm* of the Mohave specimen. <A longi-
tudinal rib is barely perceptible on the outer side of the metacone
of this tooth.

MEASUREMENTS Archaeo- Archaeo-
hippus hippus
ultimus ultimus

. , No. 19840 Type specimen No. 1689
Dm*, greatest anteroposterior diameter... 13 mm. Pee eee
Dm*, transverse diameter -......2--2.--2.-.-0c.----- 13.8 PEO ee
Dm‘, greatest anteroposterior diameter...... 13.7 Bae log ese
Wms, branS Verse. Va CUCM eecereccccsncecesceeeeesae=- a 14.5 Bei -
M', anteroposterior diameter measured

along middle of crown. .....2.....---.1..---...- 13.7 EVIE So ese eee
M’', approximate transverse diameter meas-

ured along anterior border ...................- al6 Mt 15...
M*, anteroposterior diameter measured

along middie of Crown. ......--..--2-:e---0-2e00- cere 11] il
M*, transverse diameter alone anterior

POU C rr eee eed ae ree eee eet Sy onde res 14 14.8

a, approximate.

The form of the cheek-teeth shown in the upper jaw of no.
19840 differs from Hypohippus in the greater height of the
crown, larger protoconule and metaconule, larger hypostyle, and
more abrupt inner wall of protocone and hypocone. From
Archacohippus no. 19840 differs in its somewhat higher, more
rugose crown; larger, more compressed protoconule ; much larger
hypostyle with posterior cup; and absence of internal cingulum.
From typical Parahippus the Mohave specimen differs in absence

430 University of California Publications in Geology [Vou.7

of the crochet, and in its small size. The Mohave form seems to
be distinguished from Anchitherium by relatively smaller size of
the protocone and absence of internal cingulum.

Lower Cheek-teeth—The lower jaw specimen, no. 19764, (figs.
da and 5b) represents a form which in size is near Miohippus.
The cheek-teeth are brachyodont, without evidence of cement
covering. The crowns of the molars and premolars are slightly
rugose, and tend to be somewhat higher than in the average
Hypohippus.

Figs. 5a and 5b. Parahippus(?) mourningi, n. sp. P; to M,. No. 19764,
natural size. Fig. 5a, occlusal view; fig. 5b, outer side. Mohave Miocene,
Barstow Syncline, Mohave Desert, California.

P, is considerably larger than M, in both anteroposterior and
transverse diameter. The metaconid and metastylid show a
distinct tendency to separate at the summit, the separation being
more marked than in typical Hypohippus, and less advanced
than in typical Parahippus. The entostylid is well developed.
The cingulum is well shown on the anterior and posterior sides
of the crown, but shows no distinct shelf on the outer and inner
sides.

This specimen represents an anchitheriine horse smaller than
any known to the writer from post-Oligocene horizons, excepting
Archaeohippus. It is in some respects intermediate between
Hypohippus and Parahippus. As Archaeohippus also represents
a small form more advanced than Hypohippus and less advanced

1913 ] Merriam: New Anchithertine Horses 431

than Parahippus, it might be suspected that the Mohave species is
allied to it.

The only known material representing the lower jaw of
Archaeohippus available for comparison consists of two frag-
mentary specimens from the Maseall Miocene, the typical horizon
of that genus. This material was referred to Archaeohippus
by Gidley.® The principal specimen is a piece of a lower Jaw with
P? and P*, and the roots of Pt and P*’. The teeth present are
unfortunately much worn, and the nature of the cusps cannot
be determined. The important characters shown are the dimen-
sions of the premolars, and the well-developed internal basal
cingulum on the molariform teeth. It seems probable that
Gidley’s reference of the lower teeth from the Mascall to the
genus Archaeohippus is correct, as these teeth resemble the
typical upper teeth in the presence of a basal cingulum, just as
the lower teeth from the Mohave Beds resemble the upper teeth
from that region in the absence of cingula excepting at the
anterior and posterior ends.

The dentition of specimen 19764 differs from the lower teeth
referred to Archacohippus by Gidley in the absence of external
and internal cingula, and apparently also in the proportions of
the premolars.

The form represented by the lower jaw, no. 19764, shows a
general resemblance to Hypohippus, but differs in its shghtly
higher and more rugose crowns, more clearly marked incipient
separation of metaconid and metastylid columns, and absence of
external basal cingulum.

The lower jaw differs from typical Parahippus in the very
weak separation of the metaconid and metastylhd columns, and
in the absence of cement from the crowns. The separation of
metaconid and metastylid in no. 19764 shows but little advance
beyond the stage seen in the dentition of a Hypohippus speci-
men from Virgin Valley.° In none of the cheek-teeth of no.
19764 are metaconid and metastylid pillars separated on the inner
side by more than a faint groove at the summit.

5 Gidley, J. W., Bull. Amer. Mus. Nat. Hist., vol. 22, p. 385, 1906.

6 See Gidley, J. W., Univ. Calif. Publ. Bull. Dept. Geol., vol. 5, p. 236,
fig. 1, 1908.

432 University of California Publications in Geology (Vou. 7

The character of the dentition in the lower jaw specimen, no.
19764, does not agree fully with any of the described genera.
It is intermediate between Hypohippus and Parahippus, and
evidently approximates Archacohippus in many respects. So
far as the stage of evolution is concerned, the Mohave form would
seem to come fairly near Parahippus. It shows elongation of the
crown, the lateral cingulum is reduced, and there is clearly
defined incipient division of the metaconid and metastylid pillars.

MEASUREMENTS Archaeo-
hippus
ultimus

. : : E No. 19764 No. 1700

Length, anterior side of P, to posterior side of M,.... 60 mm. © ........
P., approximate anteroposterior diameter -...............-..- 16 11.5
P,, approximate anteroposterior diameter 15.8 12

P*, transverse diameter across hypoconid 10.5 9.8
Pi ambenOposverior™ (WamM Ct Cl yec..csc-seeesceseseeresesseeescceresee= 15° - 9 {fees
P,, transverse diameter across hypoconid TO%5) esac
M,, greatest anteroposterior diameter .-.......... 1 3iGia Wee
M,, transverse diameter across protoconid QWs Os
M., greatest anteroposterior diameter ...............-.-.------- 13:6. estates
M., transverse diameter across protoconid .................- S20) eee

Relationships—The upper and lower jaw specimens (nos.
19840 and 19764) from the Mohave region resemble each other
in a number of important particulars. Their similarity in strue-
ture, and their occurrence in the same region give a reasonable
assurance that they represent the same type. The two speci-
mens show similarity in the following characters: (1) height of
tooth crowns; (2) rugosity of enamel; (3) absence of cingulum
on the protocone side; (4) stage of development, as seen in sep-
aration of metaconid and metastylid, in increase of size and
compression of the protoconule, in complication of the metaloph,
and in increase of size in hypostyle. The stage of evolution in
the two specimens shows about equal advance beyond the
dentition of Hypohippus.

As has been suggested for the two specimens considered
separately, the form represented by them shows resemblance to
Hypohippus, Archaeohippus, Parahippus, and Anchitherium. It
is in general more advanced than Hypohippus. Its habit and

1913] Merriam: New Anchitheriine Horses 433

stage of evolution are near Archaeohippus, from which it is dis-
tinguished in the upper molariform teeth by absence of cingula
on the protocone side, by higher cusps, and by a slightly more
advanced stage of development of the protocone and hypostyle,
though the metaloph is not more advanced in the Mohave form.
From the imperfectly known lower teeth of Archaeohippus it is
distinguished by the absence of external cingula, and evidently
also by proportions of the premolars. The absence of cingula
on the protocone side of both upper and lower molars may have
some significance in considering the stage of evolution, or may
concern only the matter of immediate relationship.

The Mohave type represented by specimens no. 19840 and
19764 is evidently related to Parahippus in most characters,
though distant from the typical form. The absence of a crochet
in the upper teeth, and the very slight separation of metaconid
and metastylid columns in the lower teeth, indicate a relatively
undeveloped stage. Whether this form is too primitive to be
included in Parahippus will be determined most clearly when
better material is available for study.

Some significance may attach to the fact that this form,
having a certain resemblance to Parahippus, but being relatively
primitive, occurs in strata which were presumably deposited in
a later period than the time of maximum development of the
genus Parahippus. On the other hand, the Mohave form, being
somewhat more advanced than Archaecohippus in most respects,
and occurring in strata presumably younger, might be considered
a product of modification from Archaeohippus. It is interesting
to note that in the development of the crochet, in which one
would expect advance, the Mohave form is more primitive than
the Middle Miocene Archaeohippus.

The Mohave type strongly suggests Anchitherium, from
which it seems to be separated by its shghtly larger protoconule,
separation of metaconid and metastyld columns of the lower
teeth, and reduction of the cingulum on the outer side of the
lower cheek-teeth and inner side of the upper cheek-teeth.
Anchitherium is, moreover, doubtfully represented in America.
Anchitherium( ?) zitteli of China approaches the Mohave form in
certain characters, but seems clearly separable.

434 University of California Publications in Geology [Vou.7

The relationships of the interesting form from Mohave seem
almost to require the establishment of a distinct group to give
to this species such a position in the classification as will clearly
indicate its true affinities. It could be assigned tentatively to a
place with Archaeohippus, as an advanced stage with protoconule
and hypostyle more progressive, cingulum of the protocone side
absent, and complication of the metaloph not more advanced.
It could be referred to Parahippus, as a primitive stage with
crochet undeveloped, though the metaloph shows secondary fold-
ing, and with metaconid and metastylid in beginning separation.
The reference of this form to one of the deseribed genera depends
somewhat upon the extent to which the lmits of these groups
may be expanded by later studies. A reference to Parahippus
is apparently open to fewer definite objections than a reference to
Archacohippus.

Transmitted October 13, 19138.

E er Sine ie ORO, ey

‘BORDER ¢ OF pes MOHAVE DESERT

‘
to { iS

JOHN C. MERRIAM

areonian Insti
as ae

UNIVERSITY OF CALIFORNIA PRESS |

BERKELEY JAN 20 1914

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1, The Quarternary of Southern California, by Oscar H. Hershey
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VOLUME 4. pele
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Contribution to the Palaeontology of the Martinez Group, by Charles E. W

New or Imperfectly Known Rodents and Ungulates from the John Day Se
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New Mammalia from the Quarternary Caves of California, by William J Sinclat

. Preptoceras, a New Ungulate from the Samwel Cave, California, by Eusta

Seen,

ancisco,
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PI ANP w

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF

GEOLOGY
Vol. 7, No. 23, pp. 435-441, 4 text-figures Issued December 22, 1913

NEW PROTOHIPPINE HORSES FROM
TERTIARY BEDS ON THE WESTERN
BORDER OF THE MOHAVE DESERT

BY;

JOHN C. MERRIAM

CONTENTS
PAGE
VISGYERTEROE UNCLE NOS 18 2 ere eee ee oe Benen 435
LerCrlyoyapelpeato wan §/)) Pala) uel (eu oNs{e yy a 0k ts4 0) eee ee eee ee reer eee eee ee pes 436
VEU oy ee aA aa 2) eS) 0 ay ee ee ees 440
TETOYECO ol oy oNELSH(CI)) eeVoaT HW AGNS) SANS AY Oy eee ee ene eee 440
INTRODUCTION

Investigation of the Tertiary mammal-bearing beds in the
Mohave Desert, carried on by the Department of Palaeontology
of the University of California within the past three years, has
brought to hght collections of unusual interest in two loealities.
One station is in the Barstow Syneline, north of Barstow, Cali-
fornia, and near the middle of the desert. The other locality
is in the El Paso Range on the extreme western border of the
desert.

The greater part of the Tertiary mammal collection obtained
in the Mohave region has come from exposures in the Barstow
Syncline. The fauna obtained in these exposures has been

reported by the writer’ as evidently representing a stage near

1 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol., vol. 6, p. 169, 1911.

<—eonian Inst;

\ JAN2O 1914

SAL al Muse
LL tal hiuste

436 University of California Publications in Geology [Vou.7

Upper Miocene. The representatives of the horse group known
from the Barstow Syncline include at least three forms: a Meryc-
hippus of advanced type, near M. calamarius; a large form near
Hypohippus; and a recently described species near Parahippus.?
The association of Equidae, now known from the typical Mohave
Beds north of Barstow, seems to bear out the original suggestion
that these strata are near Upper Miocene in age.

The fauna from the beds at El Paso Range contains some
elements which are quite distinct from those of the Barstow
region. Remains of horses are only fairly represented, but such
forms as are present seem to represent a different fauna from
that found in the Mohave Beds of the Barstow Syneline.

At least two types of horses are known from the beds in the
El Paso Range. One group closely aproaches the characters of
the Old World Hipparion, and may include two species. _The
other type approximates Protohippus, and possibly includes two
species. It is doubtful whether typical Merychippus is repre-
sented, and remains of Hypohippus and Parahippus have not
been certainly recognized.

The general aspect of the representatives of the Equidae
found in El Paso Range is that of a fauna distinctly later
than that of the Barstow Synecline, and approximating very late

Miocene or early Phocene.

HIPPARION(?) MOHAVENSE, n. sp.

Type specimen no. 19787, an upper premolar three with two associated
upper cheek-teeth, and several lower teeth presumably from the same
individual. From the Ricardo Beds, in the El] Paso Range, north of
Mohave, California.

Crowns of upper molars nearly straight; protocone small, separate from
protoconule and nearly circular in cross-section; enamel of the fossettes
very strongly crinkled; mesostyle of nearly uniform width.

The crowns of the upper molars are nearly straight, or but
shghtly curved, and not greatly elongated. In the type material
(figs. la to 3b), in which the enamel pheations are very strong,
the length of the crown measures about one and one-half times the
transverse diameter. In other specimens, evidently but little worn,

2 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 427, 1913.

1913 | Merriam: New Protohippine Horses 437

the height of upper cheek-tooth crowns may equal about twice
the transverse diameter. The transverse diameter of the anterior
molars and posterior premolars about equals or slightly exceeds
the anteroposterior diameter. The cement layer is well developed
on the outer and inner sides. The parastyle and mesostyle are
prominent. The external rib formed by the mesostyle is especi-

Figs. la to 3b. Hipparion(?) mohavense, n. sp. Upper cheek-teeth. No.
19787, natural size. Late Tertiary near Ricardo, California. Figs. la and
1b, M’; fig. la, occlusal view; fig. 1b, outer view. Figs. 2a and 2b, M';
fig. 2a, occlusal view; fig. 2b, outer view. Figs. 3a and 3b, P*; fig. 3a,
occlusal view; fig. 3b, outer view.

ally strong on the premolars. It narrows very gradually from
the base. The middle region of the outer sides of the paracone
and metacone crescents is flat, but may show a slight tendency to
formation of a median rib.

The small protocone is free almost to the base in most
specimens. In cross-section it is nearly circular or is slightly
elongated anteroposteriorly. The walls of the anterior and
posterior fossettes show unusually numerous plications. The
posterior wall of the prefossette and the anterior wall of the

438 University of California Publications in Geology (VoL. 7

postfossette are each thrown into six or more short folds. The
anterior wall of the prefossette also exhibits very marked
plications. The posterior wall of the postfossette shows at least
one strong fold.

The upper cheek-teeth do not closely resemble those of any
West-American species known to the writer. In some respects
they show more similarity to Neohipparion plicatile of the
Florida Phocene than to most of the western species. The general
form of the teeth, the small, round protocone, the very complexly
folded enamel of the fossettes, and to some extent the detailed
pattern of the enamel folds in the Mohave form are striking!y
similar to the expression of corresponding characters of the Old
World Hipparion species. It may be noted in this connection
that the American form N. plicatile, with which the Mohave
form has been compared, is considered by Gidley* as represent-
ing a group differing in some respects from other American
species and possibly belonging to an American branch of the
Old World Hipparion.

In dimensions and in general form the Mohave species is very
near to Hipparion richthofent of China and to the typical H.
gracile of Europe. The Mohave form seems distinguishable from
H. gracile by somewhat larger size, a more distinct tendency to
lateral compression of the protocone, shghtly wider mesostyle
ribs, and possibly by very small differences in the folding of the
enamel walls of the fossettes.

The resemblance of H. mohavense to H. richthofeni, as that
species is figured by Schlosser,* is very close. In the California
form the dimensions, cross-section of protocone, and most details
in the enamel pattern match closely the corresponding char-
acters of the Chinese species. There are small differences sug-
gesting separation; as in the tendency of the small fold of the
inner enamel wall opposite the protocone to show two or more
subdivisions in most specimens of H. richthofeni, while in the
Mohave specimens the fold is commonly simple; and according

3 Gidley, J. W., Bull. Amer. Mus. Nat. Hist., vol. 23, p. 905, 1907.

4+Schlosser, M., Siugethiere Chinas, Abh. Munich Akad., Math-Ph.
Classe, Bd. 22, Taf. 4, 1903-6.

1913 | Merriam: New Protohippine Horses 439

to the measurements given by Schlosser there is a suggestion that
the upper molars of H. richthofeni are slightly longer than in
the Mohave species.

The Mohave form differs from Hippodactylus antilopinum
of India in the more clearly rounded enamel folds, and the longer
enamel fold on the inner wall opposite the protocone. It differs
from Hipparion theoboldi in its smaller size.

Several lower cheek-teeth associated with the upper teeth
constituting the type specimen of Hipparion mohavense are pre-
sumably a part of the type specimen. The lower teeth are long-
crowned, but do not appear to have been unusually long previous
to wear. The antero-internal column formed by the metaconid
and metastylid is long anteroposteriorly, and is divided on the
medial side by a deep, wide longitudinal furrow. The enamel
folds show a tendency to form secondary plications, especially
on the inner side of the parastylid ridge, and on the anterior
side of the hypoconid pillar. The small, sharp fold common on
the antero-external angle of the protoconid is seen in several
specimens.

The form of the lower teeth is near that of certain of the
specimens of Hipparion richthofeni figured by Schlosser® and by
Koken. The enamel folds in H. richthofeni are possibly a
little more pronounced, and the crowns a little longer, but the
discernible difference appears small.

An upper cheek-tooth closely resembling the Mohave species
is known from the Coast Range region of California. This
specimen was recently referred to Hipparion or Neohipparion
by the writer.‘ It is interesting to note that a suggestion of
relationship of this tooth to Hipparion richthofeni was made by
Gidley in correspondence in 1904. The tooth had, however, been
labeled Neohipparion, and the recent reference to Hipparion by
the writer was presumed at the time the determination was made
to be at variance with that expressed by Gidley.

5 Op. cit., Taf. 4.

6 Koken, E., Palae. Abh., Bd. 3, Taf. 4, 1885.

7 Merriam, J. C., Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, p. 376,
and figs. 8a and 3b, p. 375, 1913.

440 University of California Publications in Geology (Vou 7

MEASUREMENTS OF No. 19787

128 M' M?
Anteroposterior diameter ..........2...2:c::c:sceeeeeeeeeeeeeeeees 22mm, 21.4 21.6
Transverse diameter ...........2222.00cccccceeeeeeeeceeeeeeeeeeeeeeeeee 23 22 20
WET OG MO CO, yi eee ese seneee es ae ee eeee 32-+- 32+ 37

HIPPARION(?), sp.

Two moderately worn premolars (no. 19770) representing a
Hipparion form somewhat larger than the type of H. mohavense
show enamel folds bordering the fossettes in general like those of
H. mohavense, but less pronounced and more simple. The
difference does not appear to be due entirely to age, and this
form may represent a species of Hipparion distinct from H.
mohavense.

A P? (no. 19438) may be the same as H. mohavense or may
be a distinct species. The enamel plications seem less complex
than in H. mohavense and are more acute.

MEASUREMENTS

No. 19770

ps Amber OPOSt@LIOT, Game ber cicssseecccesceecccceeccecescacescesecceereneeeoeae = 25.5 mm.
| daar (rattan aon ia oa qo{stao Nie CK S) ee er ee re ee ree eee 24
Pt) hevglit Of; CRO win: ce. soc cece eee ees se eee 30

No. 19438

P?, anteroposterior diameter —22ccccccccecce ccc cree eee eee 26
2, transverse? Guam eter oc-.etsececeeesc--ee-ccceescsecteessecestasssewer=seaeaes ate 20.7
Pe beige ht Of Cr OW a ace ease ence cece once cae cece ee eee neeee a ae as eames eee 30

PROTOHIPPUS(?) TANTALUS, n. sp.

Two large upper cheek-teeth (nos. 19434 and 21221) from
the El Paso Range differ from the Hipparion forms in the united
protocone and protoconule, curved crown, and large wide fos-
settes with crinkling of the enamel limited to their adjacent
borders. The outer styles are heavy and narrow noticeably above
the base (figs. 4a and 4b).

These specimens seem certainly different from any referred
to Hipparion mohavense or allied species. They possibly repre-

1913] Merriam: New Protohippine Horses 44]

sent a type related to Neohipparion, but are probably to be
included in Protohippus or Pliohippus. Several much worn
upper molars from the Ricardo region seem clearly of an ad-
vanced Protohippus or Pliohippus type, and may represent the
same species as the type of P. tantalus.

Figs. 4a and 4b. Protohippus(?) tantalus, n.sp.. P*(?). No. 19434,
natural size. Late Tertiary near Rieardo, California. Fig. 4a, occlusal
view; fig. 4b, outer view.

MEASUREMENTS OF No. 19434

eats aNbOTOMOSHELION VAMC tC Tye ceo-2ceeces see - esse ce ecee ees -eeee ace eeecezeecesceeecetes.c- 24.8 mm.
P*?, transverse diameter ..............22-.c:2:ccccceeccceeeeceecenececceececesceccesesceeceeoee 24
Uy ye Jae Hd vA reo} (COCO) Ae ee 48

Transmitted December 15, 1918.

» x

IVERS

poe 7a St

ITY OF CALIFORNIA PUBLICATIONS

rat BULLETIN OF THE DEPARTMENT OF
an GEOLOGY
Vol. 7, No. 24, pp. 443-464, pls. 22-25 ‘Issued January 22, 1914

PLEISTOCENE BEDS AT MANIX IN THE
_ EASTERN MOHAVE DESERT oe
© « REGION ;
BY f
‘. JOHN P. BUWALDA
5
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VOLUME 4.

1 pee ae of the Upper Region of the Main Walker River, Nevada, by Dwight —
TG wis. co.cc cescvenensndsnesantauensovencsnectaede.seessttonsscatweasescaes 1 sag) 2s sa aaa
2. A Primitive Ichthyosaurian Limb from the Middle Triassic of Nevada,-by John
Gye Merriam 22 sc-----. iii sesctece cate ntstecctaenetinde onto ccbunegendinciont ogee atta aus tee Ocean
3.- Geological Section of the Coast Ranges North of the Bay of San Francisco, by
WiC. OSM ONG 0nd. 5-222 cticeaesete nee tene nun dea tone stonenen dnnteeat ste sventy a beat bnoce nana eae on eee ee
4, Arcas of the California Neocene, by Vance C. Osmont...........21.-.2+--s-2-sesenecusererennenesesenaes
5. Contribution to the Palaeontology of the Martinez Group, by Charles E. Weaver
6. New or Imperfectly Known Rodents and Ungulates from the John Day Series, by 3
William, Sie Simelair ..- eu. sectescteweccs scsescoeseotemantbentstansescsndgnepensncsbeceeet aap eee
7. New Mammalia from the Quarternary Caves of California, by William J. Sinclair g
8. Preptoceras, a New Ungulate from the Samwel Cave, California, by Eustace L.
Br) Ore es peo a eee eet = ee rem eee ee Zieh a
9. A New Sabre-tooth from California, by John C, Merriam ..................-... a
10. The Structure and Genesis of the Comstock Lode, by John A. Reid........ asd
11. The Differential Thermal Conductivities of Certain Schists, by Paul Thelen.......... Ba,
12. Sketch of the Geology of Mineral King, California, by A. Knopf and P. Thelen......
13. Cold Water Belt Along the West Coast of the United States, by Ruliff S. Holway
14, The Copper Deposits of the Robinson Mining District, Nevada, by Andrew C.
TG ANVSOD H.5-5o cod snnxacke ok ose eo oemsecnnnersese seepage Nee seas nae ace Ree ae ae ea oan ee eee &
15. I. Contribution to the Classification of the Amphiboles. 2
II. On Some Glaucophane Schists, Syenites, ete., by G. Murgoct............---scescneccesnes a
16. The Geomorphie Features of the Middle Kern, by Andrew ©. Lawson.............:.
17. Notes on the Foothill Copper Belt of the Sierra Nevada, by A. Knopf.
18. An Alteration of Coast Range Serpentine, by A. Knopf.

Nios. 27 amd 18) in One, COVE I ea oc te ce ae nsec eme ee ee eae ee oe
19. The Geomorphogeny of the Tehachapi Valley System, by Andrew C. LaWs0D...---2nee-
VOLUME 5
1. Carnivora from the Tertiary Formations of the John Day Region, by John
SAL D7=) me 1c mena RO eR BO Uae er in a oem oarcee ee oce one iets
2. Some Edentate-like Remains from the Maseall Beds of Oregon, by William Jy
Sinclair.
8. Fossil Mollusca from the John Day and Mascall Beds of Oregon, by Robert BE. C
Stearns.
Nos. 2 and): 11 Ome COV sce se cece cee eee eee oe

4. New Cestraciont Teeth from the West American Triassic, by Edna M. Wemple.
5. Preliminary Note on a New Marine Reptile from the Middle Triassic of Neva
by John C. Merriam .........-esec-csccececeececeseccseseneeenensecnecssssnenenensnssnensnsnenensenensasesnsenecenensans

UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 24, pp. 443-464, pls. 22-25 Issued January 22, 1914

PLEISTOCENE BEDS AT MANIX IN THE
EASTERN MOHAVE DESERT
REGION

JOHN P. BUWALDA

CONTENTS

PAGE
NESGUUTT RONG WORE Sa es ae ee 443
General Geographic and Geologie Features of the Region —................. dt
re -lerstocenen Golo pty, s.2:..sccescsees-n ace ccan 28s, ceeeec cceacseceteeedeehioeteeeeccsneepeeecenaeecees 445
IPANEMA LEN AUGH 1 Fe aed Kaye SS eee 446
deistocene Wacustrall Beds. .2222cc2-22...ccccc2- ese cceeecceces eaeceecceecceeseeceesceseceeeseaeeeeen=n 448
JESSEN MO SCS Se aap ar 448
Heh sical @ hava Glens exten ste enn Hoes See ee Ae ee ere cac se ces te Secs 449
RSIEIEe MEIC ayo ANIC 1 RAPT EMCO AM Sf ee er ee 450
ERD eA AR re oes reece enero t ste cece creat eae ete c1 enters Ne 22 NAS ere cosccsbencases 451
Deformation of the Fanglomerates and Lacustral Beds —....-2W.. 451
Mode of Origin and Cause of Disappearance of Manix Lake —.......... 454
SVE ler fi@) wei Oy se tena cess cso eae eco oe oon Pee decse scot ecu. <2edceacsae/nasetstsatens 454
WDrSappearancemoue tlie Male) 2. 2rccec.sxseeee segs eee ee ese seee oer ree oe see eco eee cece ee 455

Evidence of Climatic Change in the Manix Lake Region in Pleistocene
ACTIN) ee kp a ER eee RRO 456
SOUDINI AT Vg cone Sees cess 2 Sete eco chee a steeeetssn sett Ee eres oe a ea eer eset Pak Nee 456

INTRODUCTION

While engaged in the collection of fossil vertebrate material
in the eastern Mohave Desert region for the Department of
Palaeontology of the University of California, the writer exam-
ined a series of Pleistocene mammal-bearing lake beds, which
appear to have been deposited in the latest period of deforma-
tion in that region. Excellent exposures of the beds occur along

444 University of California Publications in Geology [Vou.7

the Mohave River two miles southeast of Manix; the name Maniz
Beds is therefore proposed for them. The Pleistocene lake in
which they were deposited will be referred to as Manix Lake.

The Manix Beds were brought to the attention of the writer
by Mr. H. 8S. Mourning of Los Angeles, who had learned of the
occurrence of vertebrate fossils in this formation from Mr. John
T. Reed of San Bernardino. The writer is indebted to Professor
John C. Merriam for the opportunity of engaging in the exam-
ination and for subsequent advice and eriticism.

No reference to Pleistocene lake-beds in this region has been
found in the lterature. Some of the ranges surrounding the
basin containing the Manix beds have, ‘however, received some
attention from geologists. Lindgren,! Storms,? Campbell,°
Keyes,! Baker,’ and others have studied the geology of the
Calico Mountains to the west, and Storms® has published a brief
account of the gold-bearing rocks of the Alvord Mountains to
the north.

The geologic results offered in this paper are to be considered
as of no more than reconnaissance value, inasmuch as a large
part of the time spent in the region was occupied in searching for
vertebrate fossils in the lacustral beds.

GENERAL GEOGRAPHIC AND GEOLOGIC FEATURES OF THE REGION

The Manix Lake basin les about 120 miles northeast of Los
Angeles, and twenty to forty miles east of Barstow, California.
It is traversed by the lower course of the Mohave River, an inter-
mittent stream which rises on the higher, less arid north slopes
of the San Bernardino Mountains. After leaving the mountains

1 Lindgren, Waldemar, The silver mines of Calico, California, Trans.
Am. Inst. Min. Engineers, vol. 15, pp. 717-7384, 1887.

2 Storms, W. H., Report on San Bernardino County, in 11th Ann. (1st
Biennial) Report of the State Mineralogist, Calif. State Min. Bureau., pp.
337-869, 1893.

3 Campbell, M. R., Reconnaissance of the Borax Deposits of Death
Valley and Mohave Desert, U. 8. Geol. Surv., Bull. no, 200, pp. 12-13, 1902.

+ Keyes, C. R., Borax deposits of the United States, Trans. Am. Inst.
Min. Engineers, no. 34, pp. 867-9038, 1909.

> Baker, C. L., Notes on the later Cenozoic History of the Mohave
Desert Region in Southeastern California, Univ. Calif. Publ. Bull. Dept.
Geol., vol. 6, no. 15, p. 849-853, 1911.

6 Storms, W. H., loc. cit.

1914] Buwalda: Pleistocene Beds in the Mohave Desert 445

the river runs northward along the eastern side of the relatively
flat Mohave Desert for about forty miles to Barstow, and there
turns eastward, entering a region of higher ranges. Its usually
dry lower course reaches a point north of Scott on the Salt
Lake railroad, fifty miles east of Barstow, where a playa lake
receives and evaporates such of its flood waters as are not lost
by evaporation en route in the extremely dry desert climate.
This region of the lower Mohave River is an area of broad valleys
and of rather bold ranges, which rise above the valleys one to
three thousand feet. In its relief, climate, vegetation, and gen-
eral physical aspect the region has the characteristics of the
Great Basin, of which in reality it forms a part.

In the discussion of the rocks three divisions will for conveni-
ence be recognized: (1) the pre-Pleistocene rocks which form the
floor and walls of the basin occupied by Manix Lake in Pleisto-
eene time, (2) the Pleistocene fanglomerates underlying the
Manix Beds, and (3) the Manix Beds of lacustral origin.

PRE-PLEISTOCENE GEOLOGY

The pre-Pleistocene formations are of diverse ages and char-
acters.

West of the Manix Lake basin lie the Calico Mountains (pl.
22), formed in part of the Rosamond Series, which consists of
upper Miocene tuff-breecias, tuffs, coarse land-laid granitie de-
posits, sandstones, limestones, and clays resting on rhyolite and
overlaid uneonformably by a later lava flow. The rhyolite is
said to rest on granitic rocks.

To the north he the Alvord Mountains, Dunn Mountain, and
Cave Mountain. The core of the Alvord Mountains consists of
coarse granitic rock, presumably Mesozoie or older, in which he
patches of limestone, marble, and schist; the mass is cut by
numerous pegmatitie, aplitic, and basie dikes. On the eroded sur-
face of the granite lies a series of basic lavas, presumably of
middle Tertiary age. These are overlaid in turn, apparently con-
formably, by at least several hundred feet of very coarse, granitic
detritus. The structure of the eastern end of the Alvord Moun-
tains is anticlinal with an east-west axis, but farther west it is

446 University of California Publications in Geology (Vou.7

possible that the south front represents a degraded fault scarp.
East of the Alvord Mountains lies the well-rounded dome of
Dunn Mountain, the mass of which appears to consist largely of
schist. East of Dunn Mountain rises Cave Mountain. Through
the south flank of this imposing granitic massif the Mohave River
leaves the Manix Lake basin by a gorge cut in part in voleanies
which overlie the granite. South of the Mohave River and east
of the Manix Lake basin stand the Cady Mountains, of the
geology of which little more was learned than that basic voleanics
occur in the higher parts and that rhyolites with well-developed
east-west slaty structure, probably of early Tertiary age, are
present along the western flanks near Camp Cady. <A patch of
the older granite also is exposed in this vicinity. South of the
Pleistocene basin the Kane Mountains rise abruptly. Lavas occur
on their flanks and Campbell’ describes beds which are probably
Rosamond extending eastward toward this locality from a point
south of Daggett.

PLEISTOCENE FANGLOMERATES

The initial stage in the history of accumulation in the Manix
Lake basin was the transportation of large quantities of coarse,
more or less angular rock-waste from the surrounding ranges,
to be deposited at lower levels. The character of these waste
deposits indicates their alluvial-fan origin and therefore the
term ‘‘fanglomerates’’ has been apphed to them in accordance
with the meaning of that term as defined by Professor Andrew
C. Lawson.*

A fault near Field, and downeutting by the Mohave River,
with consequent backeutting by side gulches, have been the prin-
cipal means of exposing to view both the fanglomerates and the
Manix Beds.

The fanglomerates were deposited on the lower range slopes -
as well as on the valley areas, and are of greater areal extent
thar the overlying horizontally deposited lacustral beds of Manix

7 Campbell, M. R., Reconnaissance of the Borax Deposits of Death
Valley and Mohave Desert, U. S. Geol. Surv., Bull. no. 200, p. 12, 1902.

8 Lawson, A. C., The Petrographic Designation of Alluvial Fan Forma-
tions, Univ. Calif. Publ. Bull. Dept. Geol., vol. 7, no. 15, pp. 325-334, 1913.

1914] Buwalda: Pleistocene Beds in the Mohave Desert 447

Lake. East of Afton the Mohave River has cut into what was
the east rim of the Manix Lake basin to a depth of perhaps two
hundred feet; the fanglomerates are there seen to arch over the
core of older rocks of this anticlinal barrier and to dip down the
east slope and disappear under the later fan deposits of the desert
to the east.

The maximum thickness of the fanglomerates was not deter-
mined. From the sections exposed it is known to aggregate at
least several hundred feet.

The fanglomerates are in general characterized by coarseness
and variety of constituent materials and by lack of distinet bed-
ding. The upper one or two hundred feet lying immediately
below the lacustral beds is commonly of somewhat finer texture
than the lowest visible strata. There is abundant and sudden
variation in texture both horizontally and vertically throughout
the section, as would be expected in an accumulation of waste-
slope origin.

Along the north bank of the Mohave River, south of Field,
the lowest visible fanglomerates are made up of coarse angular
and subangular masses, commonly one to three feet in diameter,
consisting of granite, basic lava, rhyolite, schist, hmestone, and
quartz, with little semblance of bedding. <A part of the section
at this point consists entirely of black lava fragments of large
size.

In the upper part of the exposed section the fanglomerate
consists of an abundance of angular and subangular fragments
enclosed in a yellow matrix. The fragments are basie and acidic
lavas and granite, ranging up to two or three inches in diameter.
The matrix is made up largely of quartz and feldspar grains
derived from the disintegration of granitic rocks. The whole
deposit exhibits the indistinct and irregular bedding commonly
seen in alluvial deposits. Some of the uppermost fine fanglom-
erate beds two miles south of Field can be traced laterally into
the coarser materials of the alluvial fans which extend up the
west slopes of the Cady Mountains. Some strata are composed
almost entirely of pink feldspar and quartz; other thin layers are
unevenly bedded sands, probably of wind-blown origin. Well-
rounded river gravel is apparently absent from the fanglomerate

448 University of California Publications in Geology [Vou.7

section, as are also fine materials similar to playa lake deposits.
The very coarse fanglomerates lack matrix and are but little
cemented. The more finely textured upper members are com-
monly sufficiently indurated to permit erosion into a gullied
topography with steep fluted walls.

Where the fanglomerates can be observed lying on the older
rocks—plutonies and pyroclastics—as east of Afton, the surface
upon which they rest is one of erosion and often has considerable
relief. It is not known what relation in time this erosion interval
has to the development of the Ricardo erosion surface, which
truneates the folded late Miocene strata of the Mohave Desert
fifty to one hundred miles to the west, as described by Baker.°®

PLEISTOCENE LAcUSTRAL BEDS

Areal Extent—The Manix Beds cover an area of irregular
outline, measuring twenty to twenty-five miles in length, and of
not less than two hundred, perhaps more than three hundred,
square miles extent. (See pl. 22.)

The southeastern limits of the lake-beds are not definitely
known. To the south they extend nearly to the flanks. of the
Kane Mountains. To the west the deposits reach almost to Kouns.
To the northwest their limits are not certainly determinable, but
beds of similar aspect and containing similar mollusean shells are
reported by Mr. 8S. H. Gester to occur along the west flanks of
the Alvord Mountains. To the north the Manix Beds are known
to extend to the foot of the waste slopes stretching southward
from the base of the Alvord Mountains; farther east the northern
border of the beds bends around the south end of the ridge on
which Field is located, and passes along the south front of Dunn
Mountain and the west face of Cave Mountain.

The limits of the beds to the northeast are significant. The
underlying fanglomerates, because of deformation, arch over the
older rocks just east of Afton, but the lacustral beds are limited
to the west side of the arch. The eastern edge of the deposits

9 Baker, C. L., Physiography and Structure of the Western El Paso

Range and the Southern Sierra Nevada, Univ. Calif. Publ. Bull. Dept.
Geol., vol. 7, no. 6, pp. 137-1389, 1910.

1914] Buwalda: Pleistocene Beds in the Mohave Desert 449

rests for the most part on the gently sloping alluvial fans of the
Cady Mountains. Near Camp Cady the Manix Beds rest against
steep rhyolite slopes. It is improbable that the original area and
thickness of the Manix Beds have been materially reduced by
erosion.

Physical Characters —Arenaceous clays and fine argillaceous
sands constitute the bulk of the Manix Beds. Both are of hght
grayish green color. Quartz, feldspar and mica particles are the
abundant coarser constituents; the particles are imperfectly
rounded. In a part of the clays and sands there occur occasional
grains of feldspar and quartz one-eighth to one-quarter inch in
diameter, representing the little modified disintegration products
of granitic rocks. Of equal persistence with the sand and clay
strata are a few thin members which consist entirely of similar
partially rounded grains. Such strata are decidedly cross-bedded.
Excepting a little gypsum occurring locally as veins in the clays
and sands, there is no trace of caleareous or other precipitates
so commonly interstratified with Cenozoic lacustral deposits in
the Great Basin region.

The most notable characteristic of the Manix Beds is the strik-
ing evenness, persistence, and parallelism of the individual strata.
In such areas as that several miles southeast of Manix no irreg-
ularity of stratification is apparent in a view showing two to
three miles of practically horizontal beds. The individual strata
commonly show little lamination. The differences which dis-
tinguish different layers are principally those of shght variation
in coarseness of materials or in shades of color. (See pl. 23.)

The upper part of the lake-beds is usually separated from the
lower by several feet of relatively coarse material, presumably
indicating a short period of contraction or dessication of the
lake and fluviatile deposition of coarser, more highly oxidized
yellowish material. Except for this interruption the beds appar-
ently record a period of continuous deposition.

Besides the evidence afforded by the remarkably even and
persistent bedding, the fine texture, and the green deoxidized con-
dition of the sediments, further proof of the lacustral origin of
the Manix Beds lies in the abundance at more than one horizon
of fresh-water organisms. Fish vertebrae and four species of

450 University of California Publications in Geology [Vou.7

fresh-water mollusks occur at several
horizons in the beds. Shallowness and
the gradual lowering of the lake
level probably explain the searcity of

t
[we

‘daivos

marked features such as beaches, wave-
eut terraces and sea cliffs. A well-
defined pebbly beach is, however, re-
ported by Mr. W. L. Moody to occur

"44099 0} IOATY

west of Cave Mountain.
The Manix Beds are but shghtly

"$0] BIOWLOT SURF oSIBO

consolidated, and the back-cutting
from the Mohave River develops on
them a subdued type of bad-land to-
pography with smooth slopes. As ex-
posed along the Mohave River between
Kouns and Afton, they nowhere ex-
ceed about seventy-five feet in thick-

*‘So}BIOWOT[HUBF OULT “E
‘pasteael JO pvojsut [euasou sdeysed ypney

ness. Their greatest thickness is
between Field and Afton. The beds
thin out gradually toward the west.
(See fig. 1.)

Stratigraphic Relations.—The bed-

ding planes of the uppermost fanglom-
erates and those of the Manix Beds
are very nearly parallel. Since the

‘spog XIUv]y [Baysnoey “F

former are alluvial deposits and the
latter lacustral sediments, exact paral-

‘UISUG XIU] JO WI Sutsso1d IayFR “GJOog yw TAATY aavyoy Aq yIMq UBT “9

lelism of bedding planes would hardly
be expected. The approximate paral-
lelism of the two sets of beds and the
apparent evenness of the waste-slope
surface on which the first lake de-
posits were laid down indicates that
alluviation, and not erosion, was the
dominant process on the fan surfaces
at the beginning of deposition of the
lake-beds, and therefore that the

OABYOJT oY} Suope sunoyyp FO yYos sopra oary yurod wv woiz Surpuo}xe ‘Uorjoas 4soM-jsva pozi[Riduss yeYMoWOG—'T “SLT

‘OUIPPIJUB UOJFY AV[USoIIL UL SoMBd[OA JUDdOISTo[G-alq ‘T

J[NVF WIT OSV OPVIOUIOTSUBT aSIVOH °G

1914] Buwalda: Pleistocene Beds in the Mohave Desert 451

youngest fanglomerates belong to a time immediately preceding
that of lacustral deposition.

About seventy-five feet of coarse fanglomerate is reported
by Messrs. Moody and W. F. Jones to overhe the Manix Beds
on the flanks of the Cady Mountains south of Afton. Where the
unflexed beds abut against the steep slopes of the Cady Moun-
tains one to two miles east of Camp Cady, perhaps twenty-five
feet of later fanglomerate overlies the beds. As Manix Lake was
at few points bordered by steep slopes and the downcutting of
the Mohave River in this region has influenced the tributaries
to cut rather than to deposit, the accumulation of fan materials
upon the Manix Beds has not been extensive.

Fauna.—The fossil material collected from the Manix Beds
represents six species of mammals, one or more species of birds,
four species of freshwater molluses, and one or more species of
fish. Of this fauna the mammals, because of their short range
in geologic time, are the most important in age determinations.
The six forms comprise a large horse quite certainly Hquus., a
somewhat smaller horse, a large camel, a smaller camel, a mas-
todon or an elephant, and an antelope, the latter two each known
by a single digital element. The fauna is considered by Pro-
fessor J. C. Merriam to be of Pleistocene age. The stage of the
Pleistocene represented by the fauna is, however, difficult to
determine because of the paucity of species, and lack of knowl-
edge regarding the dates of extinction of the forms represented.
Because of the supposition that camels became extinct in North
America before Glacial time, the fauna may represent an early
stage of the Pleistocene.

DEFORMATION OF THE FANGLOMERATES AND LACUSTRAL BEDS

Deformative movements of considerable magnitude occurred
in the Manix Lake region just before the appearance of Manix
Lake, and again shortly after the deposition of the lake-beds.

The evidence of pre-lacustral folding is seen in the somewhat
irregular anticlinal arching of the fanglomerates on a north-
south axis passing through Cave Mountain and the Cady Moun-

452 University of California Publications in Geology [VoL.7

tains. The fanglomerates are believed to be but slightly older ©
than the Manix Beds. That this deformation was pre-lacustral in
date is shown by the limitation of the lake-beds to the west side
of this anticlinal divide. Further, the presence of beds of
extremely coarse, unworn, undecomposed material, with little ad-
mixture of fine fragments, at some horizons in the fanglomerate
series indicates that the slopes bordering the basin were steep-
ened during the deposition of the fanglomerates. These coarse
deposits are in sharp contrast with the deposits of gentle slopes,
which are finer and contain only occasional large rock masses.
The Manix Beds near Afton are tilted gently to the west and
north, due apparently to continued arching along the north-south
anticlinal axis mentioned above. The absence of embankments
composed of well-rounded fluviatile material within the narrow
valley cut in the lake-beds by Mohave River above the point where
it crosses the arched rim of the basin at Afton, probably indicates
that no sudden uplift has occurred along this axis since the
Mohave commenced cutting into the lake beds. Such an uplift
across its path would suddenly lower the river gradient and
cause the stream to deposit embankment materials in its valley
for a certain distance above the barrier.

A bold east-west scarp which is traceable for about two miles
rises along the north bank of the Mohave south of Field (pl. 24,
fig. 2). While the most striking part of the scarp has been cut
back and emboldened by the undercutting of the Mohave, its
general extent marks a fault of perhaps one to two hundred feet
displacement in the fanglomerates and Manix Beds. Near the
west end of the escarpment the lake-beds and the fine fanglom-
erates immediately underlying them may be seen dipping north-
ward at a low angle into the coarse older fanglomerates, which
have been upthrown and likewise dip to the north (fig. 1). The
lake-beds and underlying fanglomerates are gently contorted
where they dip into the fault. Three-fourths of a mile eastward
down the Mohave River there is exposed a nearly vertical plane
of contact between the coarse older fanglomerate and the finer
material; it is perhaps not the main fault-plane (pl. 24, fig. 1).
Where the Mohave crosses the escarpment still farther down
stream the coarse fanglomerates dip gently northward, with the

1914] Buwalda: Pleistocene Beds in the Mohave Desert 453

overlying finer fanglomerates on the north flanks dipping in the
same direction and disappearing under the nearly horizontal lake-
beds. The absence of remnants of the lake-beds on the upper
back slopes of the upthrown block may indicate that some of the
displacement occurred in pre-lacustral time, and that much of
the upthrown block was not covered by the lake waters. The
areal relations, dip, and folding of the lacustral beds at the west
end of the scarp plainly indicate post-lacustral movement (pl. 25,
fig. 1).

Whether the fault is of the normal or of the reversed type
cannot be stated with certainty. The gentle contortion of the
lake-beds and younger fanglomerates, where they dip into the
fault at the west end of the scarp, suggests compression and
faulting of the reversed type. The contact plane referred to
above dips seventy-five degrees northward under the older fan-
glomerates, but whether its attitude is evidence as to the type
of faulting is uncertain.

The degradation of the scarp and the wide breach cut across
it by Mohave River indicate the lapse of considerable time since
the faulting. While it is not possible to estimate accurately the
_ length of time, the faulting perhaps occurred not long after the
extinction of the lake. It may be that the faulting and the pre-
lacustral folding represent a single deformative period beginning
in pre-lacustral, and extending into post-lacustral, time.

The flat surface of the lake-beds about Manix is believed to
represent nearly the top of the lacustral deposits except where
slightly modified by one or two washes and by wind-blown sand.
That this is not a flood plain developed by Mohave River below
the upper surface of the lake beds is indicated by the absence of
well-rounded fluviatile material on the present surface, and the
absence of terrace remnants of a higher surface about the sides
of the basin. Railroad levels indicate that this plane surface
has been tilted ten or twelve feet per mile to the east in the
vicinity of Manix; in a north-south direction the surface is
practically level. A thin accumulation of quartz and feldspar
grains, left behind when the upper few inches of the soft con-
taining lake-beds were blown or washed away, invariably covers
this undissected surface.

454 University of California Publications in Geology [Vou.7

No evidence of movement in Recent time was noted in the
region. Three river terraces cut on the fanglomerates and ex-
tending along the Mohave near the fault south of Field are, to
the eye, parallel with the present river bed. No accumulations
of rounded gravels are found on these terraces. It is believed
that their formation was due to inequalities in the rate of low-
ering of the- local base level, controlled by the downcutting
through the barrier below Afton. Terraces formed by accumu-
lation of rounded gravels, which might indicate slackening of
stream gradient through deformation, are apparently absent.

Mope oF ORIGIN AND CAUSE OF DISAPPEARANCE OF MaAntrx LAKE

Mode of Origin—Manix Lake came into existence as the
result of the ponding of waters furnished principally by Mohave
River. Unless the climate of the region was much less arid in
Manix Lake time than it is today, it required a stream of consid-
erable size to support this lake during the entire year against
the drain of two hundred or more square miles of evaporating
surface and sufficient overflow to keep the lake water fresh. This
stream must have headed in an area of much greater precipitation
than occurs in this desert region. The attitude of the lake-beds
indicates that, in this immediate region, topographie conditions
have not changed so greatly since Manix time as to suggest the
possibility that some stream other than the Mohave was the source
of the water. Other than the Mohave there exists, moreover, no
notable stream in the region.

If the absence of rounded gravel in the twenty-five-mile section
of fanglomerates exposed by Mohave River in the Manix Lake
basin indicates that this stream did not pass through the region
in pre-lacustral time, it is quite possible that its entrance into the
basin was effected simply by the lengthening of its lower course
in a direction determined by the rehef. The Mohave is a stream
which derives its waters from the higher parts of the San Ber-
nardino Mountains and wastes away in the dry desert. Such
extension of this stream might be the result either of increased
water supply due to uplift of the San Bernardino Mountains,
or the extension may have been the result of the greater general

1914] Buwalda: Pleistocene Beds in the Mohave Desert 455

precipitation, which is supposed to have characterized the climate
of glacial time. Regarding the latter possibility, it is of interest
also that the Manix Lake deposits apparently record two periods
of lake expansion with an intervening period of lake contraction
or dessication. This is presumably caused by two periods of
relatively abundant water supply separated by a period of rela-
tively slight precipitation. These conditions are a parallel to
the two periods of expansion and the intervening period of
contraction or dessication believed by Russell to have obtained
in Lake Lahontan; this lake is considered to have existed during
the glacial period. Another possibility is that Manix Lake was
formed by the turning of the Mohave River into this basin as a
result of the deformation which the land surface underwent just
previous to the Manix Lake time. The possibilities above consid-
ered, so far as they relate to Manix Lake, cannot in our lack of
more detailed knowledge, be considered more than conjectures.

If the course of the Mohave River lay across this territory in
pre-lacustral time, it seems probable that the initiation of lacustral
conditions came about through the uplift across its path of such
barriers as the irregular anticline east of Afton, through which
the river has since cut a cafion.

Disappearance of the Lake-—At the point of outflow over
the rim of the basin east of Afton the Mohave undoubtedly low-
ered its channel with comparative ease through the fanglomerates
arching over the older rocks. Its downeutting in the underlying,
more resistant rocks undoubtedly proceeded more slowly, how-
ever, and it is a notable fact that the lake-beds were deposited
approximately up to the level of the top of the older rocks where
these underlying formations are exposed in the section along the
Mohave just east of Afton. In this locality the river has cut its
channel downward at least seventy-five feet in these more resist-
ant rocks (pl. 25, fig. 2).

During the existence of the lake its level gradually fell as
its outlet was lowered by downeutting. Simultaneously the level
of the accumulating sediments gradually rose. When the falling
level of the lake and the rising level of the sediments met, the
lake became extinct. Further downeutting has slowly lowered
the local base level of the Mohave and enabled it to trench the

456 University of California Publications in Geology [Vou.7

lake deposits for twenty-five to thirty miles above the resistant
rim. The stream is undoubtedly still cutting in its narrow
vertical-walled gorge through the hard rocks, and meanwhile it
has locally widened its trench in the unresistant lacustral beds
and fanglomerates above the gorge to a width of a half mile or
more, as at Camp Cady.

EVIDENCE OF CLIMATIC CHANGE IN THE MANrx REGION IN
PLEISTOCENE TIME

The quantity of water brought to the Manix region by the
Mohave River of today is in striking contrast to the supply fur-
nished by that stream during Manix Lake time. The present-day
Mohave River is dry throughout much of its lower course during
most of the year, and its spasmodie floods yield only sufficient
water to fill temporarily a playa lake of small area compared to
that occupied by Manix Lake deposits. The playa lake is reported
to be dry all but a few days or weeks of each year. The Mohave
River of Manix Lake time afforded water for the two hundred
or more square miles of continually evaporating surface of Manix
Lake, with sufficient overflow for the lake to retain its freshness.
The mean annual flow of the Mohave River has apparently greatly
decreased.

It is improbable that such causes as diversion of headwater
tributaries of the Mohave or decrease of altitude influencing pre-
cipitation of the San Bernardino Mountains watershed brought
about the lessened flow. The decreased flow apparently indicates
a decrease in the general precipitation of this and adjoining
regions since Manix Lake time. What relation such change of
climate may have had to possible Pleistocene uplift in the San
Bernardino and other high mountain ranges to the west, or to
post-glacial changes of climate, cannot be stated in the absence
of more complete knowledge.

SUMMARY

In Pleistocene time the waters of the Mohave River were
ponded in a basin in the eastern Mohave Desert region. In the
lake thus formed there was deposited a series of clays and

1914] Buwalda: Pleistocene Beds in the Mohave Desert 457

sands. The writer has termed these deposits the Manix Beds, and
has referred to the lake as Manix Lake. Fossil remains of six
species of mammals, of several birds, molluses, and fish were
obtained from the lake-beds. The mammals indicate a Pleisto-
cene age for the formation, but with out present knowledge it
is not possible to determine definitely the particular stage of
Pleistocene time. Deformation of the region occurred not long
before the origin of the lake, and to a less extent after the lake’s
extinction. No evidence was noted indicating disturbance in
very recent times. It is evident that the lake owed its origin to
changes of climate in the direction of greater precipitation over
large areas and to deformation in this or adjoining regions. The
disappearance of the lake was the joint result of the partial
filling of its basin with sediments and the downcutting of its
outlet. The evidence obtained indicates that the climate in this
region and in that to the west has become more arid since the
deposition of the Manix Lake Beds in Pleistocene time.

Transmitted June 9, 1918.

EXPLANATION OF PLATE 22

Sketch map showing approximate limits of Manix Beds.

COLDUIYSOSA L044 fS2m apnybuoz

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a sires’

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agai

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"Mlbung ssiiutoaN\\

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Bernardino Meridian

Quy WW “zg

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Seay

"10439 ‘1d30 ‘11NG ‘18Nd ‘SINVD ‘AINA

2 Id ‘4 0A [vatvmMng]

Pome

EXPLANATION OF PLATE 23

Fig. 1. Manix beds two miles south of Field, dissected by the back-
cutting of gulches tributary to the Mohave River. View shows evenness
and persistence of bedding, the type of topography developed by erosion,
and the original lake-bed surface at the skyline.

Fig. 2. Manix beds three miles south of Field. Course of Mohave
River is cut down forty to fifty feet. On left are Cady Mountains.

[460]

UNIV SCARE (PUBL SUILES DERIK GEOL [BUWALDA] VOL 7, PL. 23

ensearameagen areas toe

eee ae

>
as
7 P
:
i
ste
.
’
5
= a :
be ; ; a
a
¥
‘

EXPLANATION OF PLATE 24

Fig. 1. North bank of Mohave River one mile southeast of Field.
Coarse older fanglomerates on the left are brought up by post-lacustral
fault. Finer fanglomerates on the right are horizontal. The contact is a
plane movement, but perhaps not the main fault-plane. Note lack of
bedding in coarse materials. Mohave River in foreground (February,
1913).

Fig. 2. Looking west and up Mohave River, one mile southeast of
Field. Scarp of post-lacustral fault as emboldened by backeutting of the
Mohave into the coarse older fanglomerates. In foreground recent waste
from coarse fanglomerates above overlies the fine fanglomerates.

[462]

[BUWALDA] VOL. 7, PL. 24

BUEE DEPT. GEOL.

UNIV. CALIF. PUBL,

ivy

EXPLANATION OF PLATE 25

Fig. 1. One mile south of Field. Fine younger downthrown fanglom-
erates in right middle distance dip northward into coarse older fanglomerates
composing upthrown hill to the left. Downthrown strata uneonformably
overlain by dark-colored southward-dipping Recent fanglomerates derived
from hill above.

Fig. 2. Three or four miles east of Afton. Showing depth of cafon
cut across the anticlinal rim of Manix Lake basin by Mohave River in
Pleistocene and Recent time. Irregularly arched older fanglomerates in
middle distance, lying on older rocks of Cave Mountain exposed in fore-
ground, Cady Mountains in far distance.

[464]

UNIV SCABIES PUBES BU DERI, GEOL [BUWALDA] VOL. 7, PL. 25

UNIVERSITY OF CALIFORNIA PUBLICATIONS
BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 25, pp. 465-495, 15 text figures Issued January 22, 1914

THE PROBLEM OF AQUATIC ADAPTATION
IN THE CARNIVORA, AS ILLUSTRATED
IN THE OSTEOLOGY AND EVOLUTION
OF THE SEA-OTTER

BY
WALTER P. TAYLOR

UNIVERSITY OF CALIFORNIA PRESS
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. The Geology of the Upper Region of the Main Walker River, Nevada, by Dwight
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Contribution to the Palaeontology of the Martinez Group, by Charles E. Weaver
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TE) si Ves VeogR ee sree BARR Renner RRS ean enn A ree rceE Nr Sacha rH an Ea om sccec ese nn
A New Sabre-tooth from California, by John C. Merriam

. The Structure and Genesis of the Comstock Lode, by John A. Reid..........---.----r--ss----
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LET 0 ee eRe ey ee ROR SE Spee BBE eB eer reece oor pen tie meecntegtosassteece etc at
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UNIVERSITY OF CALIFORNIA PUBLICATIONS

BULLETIN OF THE DEPARTMENT OF
GEOLOGY
Vol. 7, No. 25, pp. 465-495, 15 text figures Issued January 22, 1914

THE PROBLEM OF AQUATIC ADAPTATION
IN THE CARNIVORA, AS ILLUSTRATED
IN THE OSTEOLOGY AND EVOLUTION
OF THE SEA-OTTER

WALTER P. TAYLOR

CONTENTS

; PAGE
BIRT TO CLT CO Tape nn seers secre ke ee INS cscs theteie estes ef ne ens vetueceiedcbcsscceSecesteeoes 466
Miatentallvandl Atckmiowled ements) <2... icf. acess nec ce ceeceneee cecceeeeee 467
He SP OTe Otsu MO mG IG CLA UUT C)2:2.82-ces-cc12c2<22-= send oeee-sateceesevccde=cévesssedescSeeesesaeditsseneets 469
Distribution and Classification of Latax -2.......20.221...22..222.ceecceeeeeeeeeeeeeeeeees 470
VDSS een] oyu aC ae a ee 470
Classification and Relationships ...................-....------ssseecesseececeeeeeceeeeeeeeeee 470
Nature of the Characters Separating Latax and Lutra ...................... 473

Differential Characters, Osteological and Dental, Apparently Related
COMA UaAtICE- Adaptations 2 ents. at ee ee 473
Characters Apparently not Related to Aquatie Adaptation -................... 475
Osteologyaamal embitvone Ot (ata xs <ce2ec-sccececcs-ce--2cteneteesencaceensccoseasecceseseecsce 476
PS a ay eC 476
HD) rainbow weeet ns, ene eee ate eS Nao ose caves. Seac seve aseec Goes seuecusce ceneecceestscessttes 478
Gromer cM @ Wamact OMS me ssteecee ces es cce dees aa2ctes 20s 5e2 252 cccesceccacseses=ceescecceseeeseeee 478
Warrmnassiails errs feet otis OS Be OR enseccies pal eee ee re ee 479
Tentative Suggestions as to Evolution of Dentition ................... 480
TANI exo Ee, Feral RAW aT) ast ee ee aa ea eR aoe 481
AMET cates ee eee ES ee ee ee 482
NACHRS OEE I a 483
Generali Chana cb ers: ccc: sac oecs sfc secee chee a cabsenscncctenceecece-teeecueaeteeesdeuesnce ses AHets}
ES ASV ODEN Sa ee 484
CCN NCR, ee ce re ee 484
Relation of Vertebral Characters to Aquatie Adaptation —....... 485
SLO OCU a ee ee eee 485

466 University of California Publications in Geology (Vou.7

Stage! of Hiviolution o£ Waitax: ese. se sess cee: sees ee 491
Palaeontologic Evidence Bearing on Problem of Origin of Sea-otter.... 492
‘Viaria tion: in Liattax 2, ooo ecco eeeee ee eee ee 493
SUNN 11 Typ esac cos coe cee ace ees ene rece et we age eee 495

INTRODUCTION

Adaptation to life in the water presents many possibilities
in connection with studies of variation of form, since the influ-
ence of the factor of environment is so nearly a constant, and
the nature and direction of the variation may be clearly seen.
This is especially true of animals which have been adapted to life
on land, and have later entered upon an aquatic existence. In
such eases one should be able, from a consideration of their
present form and palaeontologice history, to follow the course of
evolution with more than usual certainty. Under these cir-
cumstances, when the nature and significance of the changes
are so clearly shown, there should also appear to be a greater
probability of gaining some insight into the process by which
these changes are effected. Unfortunately, this ideal is in few
if any cases attainable, partly because ancestry often can not be
traced, owing to lack of the necessary palaeontologic material.

The aquatic Mammalia, the Cetacea, Sirenia and Pinnipedia,
are groups already far advanced in adaptation. Since they are at
present almost exclusively marine, they offer an especially wide
field for investigation of this kind. Work upon these highly special-
ized groups, however, does not to any extent reveal data on the
beginning stages of adaptation to aquatic life, and the early
structural changes are, in many respects, the most significant,
especially from the point of view of an enquirer into the nature
of the processes involved.

A study of the sea-otter (Latar lutris) might presumably
be of value in this connection, since the animal is one exhibit-
ing variations which are probably, in some degree, analogous to
those shown by the ancestors of the groups above mentioned not

1914] Taylor: Aquatic Adaptation in the Carnivora 467

long after they took to the water. The ancestry of this species
is at least roughly traceable, as its structure shows it to be
closely related to the river otter (Lutra canadensis). At the
same time, Lata possesses characters which are certainly to be
interpreted as incipient adaptations to an exclusively aquatic life.

The present paper is the result of a study carried forward in
continuation of work done by Professor John C. Merriam!" on
the problem of aquatic adaptation as illustrated in the history
of certain of the marine reptiles of the Mesozoic, especially the
Thalattosauria and Ichthyosauria.

Fig. 1. Latax lutris nereis (no. 6956. Univ. Calif. Mus. Vert. Zool).
Drawn from the skin.

It is intended in this paper (a) to present a detailed discussion
of the osteological and dental peculiarities of Latar; (b) to
submit conclusions from a study of the palaeontologie history of
the group; (c) to analyze the characters of Latax, so far as
possible, and to consider them in the light of aquatic adaptation ;
and (d) to discuss the bearing of the material presented on cur-
rent theories of species formation.

MATERIAL AND ACKNOWLEDGMENTS

Through the interest and generosity of Miss Annie M. Alex-
ander a complete specimen of the southern sea-otter, Latax lutris
nereis Merriam, C. H., (no. 6956, Univ. Calif. Mus. Vert. Zool.,

1 Merriam, J. C., ‘‘ Triassic Ichthyosauria, with special reference to
the American forms,’’ Mem. Univ. Calif., vol. 1 (1908), no. 1; and ‘‘The

Thalattosauria, a group of marine reptiles from the Triassic of California, ’’
Mem. Calif. Acad. Sci., vol. 5 (1905), no. 1.

468 University of California Publications in Geology [Vou.7

data: 9 adult; Point Sur, Monterey County, California; March
10, 1908; collected by J. Rowley) now a very rare animal off the
coast of California, has been added to the collection of the
Museum of Vertebrate Zoology of the University of California,
and makes possible the present study. Additional material
at hand consists of a skull of Latax lutris lutris (Linnaeus) (no.
8124) from the collection of the Department of Palaeontology of
the University of California, as well as a number of skulls and
skeletons of Lutra canadensis (Schreber), Taxidea tarus (Sehre-
ber) and Phoca vitulina Linnaeus, contained in the collection of
the Museum of Vertebrate Zoology and in that of the Depart-
ment of Palaeontology of the University of California.

Fig. 2. Camera lucida drawing of skeleton of Latax lutris nereis (no.
6956. Univ. Calif. Mus. Vert. Zool.).

The sex of the specimen of Latar lutris lutris is unknown,
hut the size of the skull and the degree of development of the
processes for muscle attachment, together with the degree of

wear of the teeth and ankylosis of the bones, might indicate
that it is an old male.

Through the kindness of Professor Edwin Chapin Starks of
Stanford University, the writer has been enabled to examine a
mounted skeleton of an adult Latax lutris nereis in the museum
of that institution.

Grateful acknowledgment is made to Professor John C.
Merriam, head of the Department of Palaeontology of the
University of California, for generous criticism and suggestion.

1914] Taylor: Aquatic Adaptation in the Carnivora 469

The writer was assisted in many ways by Dr. Joseph Grinnell,
director, and by Dr. H. C. Bryant and Mr. F. H. Holden, mem-
bers of the staff, of the Museum of Vertebrate Zoology of the
same institution, and desires to express to them his appreciation.

The drawings were made by Mrs. Louise Nash.

HISTORY OF THE LITERATURE

The osteology of the sea-otter has been discussed by Home,?
who notes several points with regard to skull (two plates of the
skull and lower jaw are given), skeleton, and external characters,
but considers internal anatomy at greater length; Lichtenstein,
who is said to have figured the skull; Martin,* who described the
skeleton of the sea-otter in some detail; Baird? who, in character-
izing the sea-otter, incidentally mentions skull characters; Ger-
vais,” who worked out the osteology and discussed the systematic
position of Latar, and by Coues,® who discusses quite compre-
hensively the habits, characters and systematic status of the
animal, and gives the leading references to the sea-otter.

Many naturalists, explorers, and traders, as well as a number
of both the earlier and later historians, refer, at least casually,
to the sea-otter. The fact of its former great abundance on
the shores of the North Pacific is recorded in many places.*. The
progress of civilization has witnessed the steady increase in the
efficiency of man as a hunter, and a corresponding diminution
in numbers of this intrinsically interesting and economically
important animal, until now, from all accounts, it has become so
rare an animal as to be approaching extinction everywhere.

2 Home, E., ‘‘A description of the anatomy of the sea-otter.’’ Phil.
Trans. R. Soe., London, 1796, p. 385.

3 Martin, W. C. L., ‘On the Osteology of the Sea Otter Enhydra marina
Flem.’’ Proce. Zool. Soe., London, pt. 4 (1836), pp. 59-62.

4 Baird, 8. F., ‘‘General report upon the mammals of the several
Pacific railroad routes,’’ pt. 1 (1857), p. 189, in Mammals of North
America, (Philadelphia, J. B. Lippincott and Company, 1859),

5 Gérvais, Journ. de Zool., vol. 4 (1875), pp. 200-206.

6 Coues, E., ‘‘ Fur-bearing animals.’’ U.S. Geol. and Geog. Surv. Terr.
Mise. Pub. 8 (Washington, Government Printing Office, 1877), p. 325.

7 For example, see Smythe, W. E., History of San Diego (San Diego,
The History Company, 1907), pp. 68, 88, 107.

470 University of California Publications in Geology [Vou.7

DISTRIBUTION AND CLASSIFICATION OF LATAX

DISTRIBUTION

The northern sea-otter, Latar lutris lutris (Linnaeus), in-
habits the coast and islands of the North Pacifie Ocean. In
1904 C. H. Merriam*® described a southern subspecies from the
Santa Barbara Islands (Latar lutris nereis, type from San
Miguel Island). Coues® gives the range of the sea-otter as south
to Lower California. The limits of the range of the two sub-
species are not determined.

CLASSIFICATION AND RELATIONSHIPS

Many early writers observed the resemblance of the sea-otter
to the seal. Pennant!’ noted the resemblance of the two in tooth
formula. He also called attention to their likeness in habits.
Referring to sea-otter, he states: ‘‘These animals partake very
much of the nature of seals in their almost constant residence
in the water, their manner of swimming, finlike legs, and number
of fore teeth.’’ In the same account he says: ‘‘They are seen
very remote from land, sometimes even at the distanee of a
hundred leagues.’’ Pallas,’t as noted above, referred the animal
to the genus Phoca. Martin, with reference to the close resem-
blanece between the two, states’? that between the seals and the
otters the Enhydra forms a palpable link of union, approxi-
mating, in some portion of its osseous structure, even more to the
former than to the latter. Baird (1857) practically repeats this
statement. ‘‘The sea-otter, the sole representative of the genus
so far as known, is an exceedingly remarkable animal, with per-
haps more resemblance to a seal than to the common otters.’’!*
Scammon™ includes the sea otter in the Pinnipedia. Coues is

8 Merriam, C. H., ‘‘A new sea-otter from southern Catifornia,’’ Proe.
Biol. Soc., Wash., vol. 17 (1904), p. 159.

9 Coues, E., op. cit., p. 327.
10 Pennant, T., Arctic Zoology (London, Henry Hughs, 1784), p. 91.

11 Pallas, P., Zoographia rosso-asiatica (Petropoli ex officina Caes.
Academiae Scientiarum MDCCCXT), p. 100.

12 Martin, W. C. L., op. cit., p. 59.
13 Baird, S. F., op. cit., p. 189.

14 Seammon, C. M., Marine mammals (San Francisco, John H. Carmany
& Co.; New York, G. P. Putnam’s Sons; 1874), pp. 168-174.

1914] Taylor: Aquatic Adaptation in the Carnivora 471

much more conservative, remarking’ that the hind limbs are de-
veloped into flipper-like organs, similar to those of some seals.
He notes the general likeness of the skulls of the seal and sea-
otter, and says: ‘‘In general superficial aspects, the Sea Otter
is not unlike a Seal, a resemblance increased by the flipper-like
hind feet.’’ Coues is apparently the first author who clearly
discriminates between superficial resemblances to the seal and
the real and close affinities with the rest of the otters.

Gill'® divides the subfamilies of the Mustelidae into two
groups, the first including the Mustelinae, Mellivorinae, Melinae,
Helectidinae, Zorillinae, and Mephitinae, and the second includ-
ing the Lutrinae and Enhydrinae.

His characterization of the two groups follows:

“(7 —Skull with the cerebral portion comparatively compressed back-
wards; and with the rostral portion comparatively produced, attenuated
and transversally convex above; anteorbital foramen small, and opening
forwards. Feet with little-developed or no interdigital membrane.

«¢?.—Skull with the cerebral portion swollen backwards and _ out-
wards; and with the rostral portion abbreviated, high and truncated
forwards, and widened and depressed above; anteorbital foramen en-
larged, and produced downwards and backwards. Feet with well-
developed interdigital membrane, and adapted for swimming.’’

It will be noted that the fundamental resemblances of the
sea and river otters are presented in the characters of group 2.

According to Gill’s classification, the Enhydrinae are separ-
ated from the Lutrinae on the basis of the tooth formula and the
elongation of the digits of the posterior feet.

The characters mentioned above under the second group serve
to hold Gill’s two subfamilies (Lutrinae and Enhydrinae) to-
gether in a broad way. Other common characters are (and these,
of course, are more intangible) the general similarity in shape of
body, length of tail, and habits.

With the possible exception of the digits of the hind feet,
every part of the skeleton of Latar clearly resembles in general
form and shape the corresponding part of Dutra. The differ-
ences elaborated below rest on close serutiny and comparison.

15 Coues, E., op. cit., pp. 325, 327.

16 Gill, T., ‘‘Synoptical tables of characters of the sub-divisions of

mammals, with a catalogue of the genera.’’? Smithsonian Inst., Mise.
Collect., vol. 11 (1871), pp. 64, 65.

472 University of California Publications in Geology [Vou.7

Although the divergencies are expressed in nearly every part
of the skeletal structure, they are, in most instances, small in
amount.

With regard to the tooth formula, Coues states: ‘‘It is said

that the young Sea Otter has I = like all other Mustelidae.

.’ Unfortunately, he omits the authority for this asser-
tion. If the young Lataxr does possess three incisors below on
each side, the different incisor formula of the genus would be
clearly shown to be not in any way a profound or fundamental
distinction. It may be questioned further whether the loss by
the sea-otter of P* is a difference any more deep-seated than the
loss of the middle pair of lower incisors. The loss of certain
anterior premolars is well known to be comparatively frequent
in fissipedian carnivores, while incisor loss is comparatively rare.

The modification of the digits of the hind foot, though strik-
ing, would not seem to the writer to be of sufficient importance
to warrant the reference of the sea-otter to a subfamily distinct
from the Lutrinae.

If Latax is left in the subfamily Lutrinae, the classification
in a measure fails to show the differences existing between the
two genera. If, on the other hand, the sea-otter is referred to a
distinct subfamily, the classification certainly does not indicate
the fundamental resemblances of the two genera. Apparently the
question is one of whether the differences or the resemblances
seem to the individual author of most significance. Baird,* Os-
born,’® Trouessart,?° Ellot,°? and Stephens”? refer the sea-otter
to the subfamily Lutrinae, while Gill?* and Coues** make it the
sole genus in the subfamily Enhydrinae.

17 Coues, E., op. cit., p. 326.

18 Baird, 8. F., op. cit., p. 189.

19 Osborn, H. F., The age of mammals (New York, the Macmillan Co.,
1910), p. 531.

20 Trouessart, E. L., Catalogus mammalium (Berolini, R. Friedlander
& Sohn, 1898, 1899), vol. 1, p. 281.

21 Elliot, D. G., ‘‘Synopsis of the mammals of North America,’’ Pub.
Field Columb. Mus., Zool. Ser., vol. 2 (1901), p. 351; and ‘‘Cheeck list of
North American mammals,’’ same series, vol. 6 (1905), p. 433.

22 Stephens, F., California mammals (San Diego, West Coast Pub. Co.
9 929
1906), p. 232.

23 Gill, T., op. cit., p. 65.
24 Coues, E., op. cit., p. 325.

1914] Taylor: Aquatic Adaptation in the Carnivora 473

The facts of relationship seem to the writer to be somewhat
more adequately shown by the former course, and consequently
the sea-otter is here referred to the Lutrinae.

NATURE OF THE CHARACTERS SEPARATING LATAX AND LUTRA

Although, as previously suggested, a superficial examination
of the skeleton of Latar reveals no very emphatic modifications
in the form of the bones, except in the hind foot, such as might
be expected to occur in response to an aquatic environment, a
closer scrutiny brings to light the fact that adaptations of this
nature affect almost every bone in the body, and indicates that,
outside the Pinnipedia, Latar is the most highly specialized for
life in the water of all the carnivores.

Reference to the following table shows further that many of
the characters distinguishing Latar lutris nereis from Lutra
canadensis may be ascribed to the effect of natatory modification.

DIFFERENTIAL CHARACTERS, OSTEOLOGICAL AND DENTAL,
APPARENTLY RELATED TO AQUATIC ADAPTATION

Lutra canadensis Latax lutris nereis

1 Skull relatively not enlarged 1 Skull heavy, massive, rela-
in proportion to length of tively much enlarged in
trunk. proportion to length of

trunk.

2 Brain-case relatively not in- 2 Brain-case inflated.
flated.

3. Orbit small relative to length 3 Orbit large relative to length
of skull. of skull.

4 Lambdoidal ridge and sagittal 4 Lambdoidal ridge and sagit-
crest little developed. tal crest highly developed.

5 Anterior ends of nasals a short 5 Anterior ends of nasals al-
distance posterior of an- most directly above anter-
terior ends of premaxil- ior ends of premaxillaries.
laries.

6 Interorbital constriction nar- 6. Interorbital constriction broad.
row. ,

7 Tooth formula 7 Tooth formula
oT i208 Se aay

8 Cheek-teeth with a _ cutting 8 Cheek-teeth with a crushing
function. function.

9 Lower carnassial with para- 9 Lower carnassial with para-

conid large. conid much reduced.

474

Lutra canadensis
Foramen lacerum posterius
small.
Neck long, nearly 3/10 length
of trunk.
Tail with about 24 vertebrae.

Intervertebral foramina small.
Zygapophyses comparatively
highly developed,
Anapophyses present on all
the lumbar vertebrae but
the fifth and sixth.
Vertebral centra long antero-
posteriorly, dorso-vent ra 1
measurement relatively small.

Epiphyses less developed.

Vertebrarterial foramen of
atlas small, round; trans-
verse process plate-like,
thin, expanded; dorsal arch
broad antero-posteriorly.

Spine of axis antero-
posteriorly.

Vertebrarterial canal of sixth
cervical vertebra small;
transverse process divided
into three parts, one lateral
peghke, and two ventro-
lateral platelike processes.

Transverse process of third
lumbar vertebra platelike;
metapophyses wide; ana-
pophyses highly developed.

long

Sacrum with zygapophyses in-
dicated; transverse process
on posterior sacral.

Chevron present on fourth
caudal vertebra.

Ribs light.

Pelvis comparatively light;

obturator foramen bounded
by light bars.

Pelvis forming shght angle
with vertebral column.
Ilia not markedly flaring

anteriorly.
Fore limb
large.
Olecranon of ulna slightly
larger than in Lataa.

comparatively

University of California Publications in Geology

dul

ily
18

[ VoL. 7

Latax lutris nereis

Foramen lacerum posterius
large.

Neck short, less than 2/10
length of trunk.

Tail with number of verte-
brae reduced, varying
from 18 to 21.

Intervertebral foramina large.

Zygapophyses not so highly
developed.

Anapophyses present on first
three lumbar vertebrae
only.

Vertebral centra short antero-
posteriorly, dorso-vent ral
measurement relatively large.

Epiphyses greatly developed.

Vertebrarterial foramen of
atlas large, round; trans-
verse process heavy; dor-
sal arch narrow antero-
posteriorly.

Spine of axis short antero-
posteriorly.

Vertebrarterial canal of sixth
cervical vertebra large;
transverse process divided
into three peglike pro-
cesses.

Transverse process of third
lumbar vertebra short and
peglike; metapophyses nar-
row; anapophyses indicated
merely.

Sacrum with no zygapophyses
indicated; small transverse
process on posterior sacral.

Chevron absent from fourth
caudal vertebra.

Ribs heavy.

Pelvis comparatively heavy;
obturator foramen bounded
by heavy bars.

Pelvis more nearly parallel to
vertebral column.
Ilia markedly flaring

teriorly.

Fore limb comparatively small.

an-

Olecranon of ulna slightly
smaller than in Lutra.

1914]

acters, or 30.4 per cent, are apparently not so related.

Lutra canadensis
Hind limb not specialized for
use as a paddle.

Head of femur with pit for
ligamentum teres,

Tibia and fibula long and
light.
Pes not expanded.
Metatarsals and _ phalanges
not noticeably elongated
or flattened.
5 Fifth digit not the longest.

Hind limb not markedly back-
ward extending.

Taylor: Aquatic Adaptation in the Carnivora 47

ea |

Latax lutris nereis
Hind limb specialized for use
as a paddle.
Head of femur without pit for
ligamentum teres.
Tibia and fibula comparative-
ly heavy

Pes expanded.

Metatarsals and phalanges
noticeably elongated and
flattened.

Fifth digit the longest.

Hind limb markedly baeckward-
extending.

CHARACTERS APPARENTLY NOT RELATED TO AQUATIC
ADAPTATION

Lutra canadensis

Infraorbital foramen large but
not so elongate as in
Latax.

Zygomatie process of frontal
prominent.

Angular process represented
by a hook and internal shelf.

Zygomatic arches fairly wide-
spreading,

Coronoid process rounded and
bent forward.

Incisive foramen oval.

A large condylar vacuity pres-
ent 3.17 mm. from foramen
lacerum posterius.

Spine of fifth thoracie verte-
bra platelike, rounded pos-
teriorly; ending in knob.

Suprascapular border of sca-
pula having a dip in the
curve.

Deltoid ridge of
somewhat
definite.

Entepicondylar foramen bound-
ed by light bar; elongate.

humerus
expanded, in-

Latax lutris nereis

Infraorbital foramen large
and elongate.

Zygomatic process of frontal
less prominent.

Angular process indicated by
tubercle.

Zygomatic arches not so wide-
spreading.

Coronoid process rounded and
bent backward.

Incisive foramen more nearly
round.

A minute foramen present
near condyle 7.3 mm. from
foramen lacerum posterius.

Spine of fifth thoracic verte-
bra thicker, straight, not
rounded posteriorly; not
ending in knob.

Supraseapular border of scap-
ula having an even curve,
no dip.

Deltoid ridge of humerus a
definite single ridge.

Entepicondylar foramen bound-
ed by heavy bar; small.

From these tables it develops that 36 characters, or 69.6 per
cent, are apparently related to aquatic adaptation, while 11 char-

Although

476 University of California Publications in Geology [Vou.7

this classification of the characters is subject to modification, and
the statistical statement not all that could be desired, since
account cannot well be taken of the relative importance of the
characters, still it is believed that in the main what seems to be
shown is very near the truth.

OSTEOLOGY AND DENTITION OF LATAX
SKULL
The comparative size of three skulls examined is shown by
the following measurements, all in millimeters:

Lutra canadensis Latax lutris Latax lutris
nereis (no. 6956) __lutris (no. 8124)

Greatest length of skull—most

posterior surface occipital con-

dyle to most anterior surface

Of premaxillariys 2 ee :ctenctees- pees 106.8 114.1 132.9
Height of skull at auditory

bulla—taken perpendicularly

to basicranial axis of skull...... 36.9 60.2 63.7
Greatest breadth of skull at

mastoid process, measured ex-

WG CTO Tel ys Re eo ies ere hee eee 63.2 83.1 Oe

These dimensions indicate the heavy and massive character
of the cranium of the sea-otter, and clearly show that as com-
pared with the skull of Lutra canadensis that of Latax lutris
nereis is larger relatively to length of trunk.

The brain-case is more bulky in the southern sea-otter (no.
6956) than it is in the river otter, the skull of Latar l. lutris (no.
8124) having this bulkiness still more emphasized.

The latter skull (no. 8124) evidently belonged to an old
animal (possibly a male), as the sutures are discernible in only a
few places, and the sagittal crest and lambdoidal ridge, as well
as other processes for muscle attachment, are very highly devel-
oped.

The lateral boundary of the anterior nares, formed by the
premaxillaries, is in the sea-otter more nearly perpendicular than
in the river otter. Consequently, the skull may be described as
being high anteriorly, the nasals being more above the incisors.

1914] Taylor: Aquatic Adaptation in the Carnivora 477

The orbit in the two skulls of the sea-otter is relatively (to the
leneth of the skull) larger than in the Lutra canadensis. This
enlargement may be due to an increase in size of the visual organ
to adapt the animal for sight under water, paralleling the con-
ditions in this respect observed by J. C. Merriam?’ and others in
ichthyosaurs, in which group the orbits of the later Jurassic
forms are larger than in the earlier Triassic reptiles. The relative
enlargement of the skull of Latax lutris may also be definitely

Fig. 3. Skull of Lutra canadensis (Univ. Calif. Col. Palae.) x14.
Fig. 4. Skull of Latax lutris (no. 8124, Univ. Calif. Col. Palae.) «1%.

related to aquatic adaptation. The later ichthyosaurs, those
which had lived longest in the water, had larger skulls relatively
to the length of the trunk than those of earlier periods. As an
extreme example of this kind of skull modification, the whales,
in which the proportionate size of the skull is tremendous, may
be cited.

25 Merriam, J. C., ‘‘Triassie ichthyosauria, with special reference to
the American forms,’’? Mem. Univ. Calif., vol. 1 (1908 A.
, ’

478 University of California Publications in Geology \Vou.7

The general rounding of the profile of the sea-otter skull and
the increased width of the interorbital constriction result re-
spectively from the increased mass of the brain-case and the
enlargement of the skull as a whole. The lesser prominence of
the zygomatic process of the frontal and the reduction of the
angular process of the mandible may be related to aquatic adapta-
tion in that they signify a general reduction in the angular tuber-
osities for muscle attachment, which has been found by Raymond
Osburn”* to be indicative of natatory modification. There might
theoretically be a reduction in certain angular tuberosities for
muscle attachment (those to which the supporting muscles are at-
tached) as an animal became adapted to life in water. The
medium does not require the development of such heavy muscles
as are required on land for support and locomotion, and so would
not necessitate the production of large processes for their attach-
ment.

DENTITION

General Characters.—Upon comparing the teeth of Lutra and
Latax one is impressed immediately by the broader and more
rounded character of the cheek-teeth of the latter. Coues ex-
presses it well in saying: ‘‘If the teeth of ordinary carnivorous

Figs. 5-6. Teeth of Latax and Lutra (natural size).

Fies. 5a and 5b. Milk ecarnassial, true lower carnassial and second
lower molar of Latax lutris nereis. Fig. 5a, superior view;
5b, lateral view.

Figs. 6a and 6b. Lower carnassial and second lower molar of Lutra
canadensis; Fig. 6a, superior view; 6b, lateral view.

26 Osburn, R. C., ‘‘Adaptive modifications of the limb skeleton in
aquatic reptiles and mammals,’’ Ann. Acad. Sci. New York, vol. 16
(1906), p. 449.

1914] Taylor: Aquatic Adaptation in the Carnivora 479

quadrupeds be likened to fresh-chipped, sharp and angular bits
of rock, those of the Enhydrinae are comparable te water-worn
pebbles.’’** Evidently the cheek-teeth have entirely lost their
sectorial and prehensile functions.
3.13

The tooth formula of Latax pee

tol —
‘

< 2—= 82 ) is somewhat

reduced as compared with that of Lutra Gr3'2 x 2= 36) ;
The loss of a pair of lower incisors is a modification analogous to
the case in seals, which, as is well known, have only two pairs of
these teeth. This is one of the points which seemingly indicates
that, from an evolutionary standpoint, the sea-otter is traveling
in the general direction of the pinnipedian carnivores.

Carnassials—One specimen (no. 6956) retains the milk ear-
nassial in the lower jaw. This tooth was evidently about to
be shed. Immediately behind it is the permanent carnassial.
The tuberculation of the milk carnassial resembles that in
the lower carnassial of Lutra canadensis, which has well-
developed protoconid, paraconid and metaconid, with a heel made
up of hypoconid and entoconid. These facts probably indicate
that the ancestral form from which Lataxr is descended possessed
a carnassial in form resembling that of Lutra canadensis. An-
other item confirming this view is that the milk carnassial is not
so flattened and rounded in appearance as the true lower car-
nassial, but the ridges and tubercles are more acute. Of course
if the food of the young sea-otter after the animal is weaned is
different from that of the adult there might be adequate reason
for the differences in the form of the carnassial here noted, which
differences would then have no phylogenetic significance. There
is no evidence, however, that there is any difference in food
between adult and weaned juvenal.

The permanent carnassial exhibits a very great reduction of
the paraconid. Reduction and ultimate loss of the paraconid are
generally correlated with the assumption of a crushing function.
In the case of the sea-otter, the acquisition of a more purely
crushing function seems to be associated with aquatic adapta-
tion.

27 Coues, E., op. cit., p. 325.

480 University of California Publications in Geology (Vou.7

Tentative Suggestions as to Evolution of Dentition—Accord-
ing to H. W. Elhott,?* C. M. Scammon”® and others, the sea-otter
feeds to some extent on fish, but for the most part on sea-urchins,
crabs, mussels, and clams. This would seem to account for its
highly specialized crushing dentition. It is of interest to note in
this connection that a primitive ichthyosaur from the middle
Triassic (Phalarodon fraasi)*° has a crushing dentition, the teeth
being of a thick, low-crowned type. This is in marked contrast
with the dentition of later Jurassic ichthyosaurs*! which have
teeth of a simple subconical type. It would seem possible that in
ichthyosaurs the crushing dentition was one of the early steps in
aquatic adaptation.

In the course of the evolution of any pelagic mammal which
is descended from a land-living species, there may be three
habitat stages, namely, (1) one in which the animal is terrestrial
only (and would ordinarily possess molars with conical or with
compressed tubereles for securing and killing active land ani-
mals); (2) one in which the animal preys upon organisms of
the littoral zone (and might have a crushing dentition) ; (3) one
in which the animal depends upon pelagic forms and fishes which
it does not crush or masticate (and might have slender teeth).

It might be expected that when a terrestrial species takes to
aquatic life it would first become gradually accustomed to feed-
ing on animals of the lttoral zone, probably using a few land
or river forms at the same time. As it progressed in adaptation
to life in the water and became more specialized, it would depend
to a continually greater degree on littoral animals for food. At
this stage of evolution such a species would best be served by a

28 Elliott, H. W., ‘‘ Report upon the condition of affairs in the Terri-
tory of Alaska.’’ House Exec. Doc. 83, 44th Congress, Ist Session (Wash-
ington, Government Printing Office, 1875), pp. 54-62.

29 Seammon, C. M., Marine mammals (1874), pp. 168-174. Snow (In
forbidden seas, London, Edward Arnold), 1910, pp. 279-280, asserts that
remains of clams, limpets or mussels were not found in a single one of
hundreds of stomachs examined by him, the food consisting principally
of crabs, sea-urchins, sea-squirts, and what looked like fish-spawn (see
p. 481).

30 Merriam, J. C., ‘The skull and dentition of a primitive ichthyosaurian
from the middle Triassic,’’ Univ. Calif. Publ. bull. Dept. Geol., vol. 5
(1910), p. 383.

31 Merriam, J. C., ‘‘Triassie ichthyosauria,’’ ete., Mem. Univ. Calif.,
vol. 1 (1908), p- 74.

1914] =» Taylor: Aquatic Adaptation in the Carnivora 481

crushing dentition, for its food would consist of crustaceans,
echinoderms and similar animals. Recent Lataxr represents a
genus presumably specialized to this extent, although the exact
status of the animal in this respect is not now certainly deter-
mined. <A recent writer (Snow) ,°? whose twenty years of experi-
ence hunting the sea-otter lend authority to his statement, asserts
that the animal dives to get its food, ordinarily in water of from
10 to 25 fathoms depth. As to the nature of the food, Snow states
that the examination of hundreds of sea-otter stomachs reveals
the fact that crabs, sea-urchins, sea-squirts, and a substance that
looked like fish-spawn, are chiefly fed upon. He found no trace
of seaweed, clams, limpets or mussels, and very seldom of fish.
The crabs and similar animals were chewed up and swallowed
shell and all. He says further that the sea-otter is very shy and
sensitive, and nowadays rarely comes on shore, though according
to accounts given by Steller and others it was formerly in the
habit of ‘‘hauling out’’ on the rocks and beaches in large num-
bers.

Further adaptation of our hypothetical species might imply
independence of shore animals, and the ability to make use of
pelagic forms for food. <A simple, subconical type of den-
tition to serve a prehensile function would be the most advan-
tageous at this stage, for the food would consist of such animals
as cephalopods and fish. The later Jurassic ichthyosaurs and
the modern Phoca approximate this degree of adaptation, al-
though this does not imply that phylogenetically the teeth of
these forms have passed through a thick, low-crowned stage.

NECK AND TRUNK

The neck of the animal is very much shorter relatively to
leneth of trunk than in Lutra canadensis. In this it resembles
the seal, which has a proportionately very short neck. In the
porpoise (Phocaena) the shortening has advanced to such a de-
eree that the anterior cervical vertebrae are completely fused,
and the posterior ones are indicated by thin spines only. In the
sea-otter the centra and dorsal arches of the cervical vertebrae

32 Snow, H. J., In forbidden seas (London, Edward Arnold, 1910),
pp. 278-280.

482 University of California Publications in Geology {Vou.7

are much shortened anteroposteriorly. Actual numerical pro-
portions in the sea and river forms follow:
Latax Lutra

lutris nereis canadensis
Length of trunk measured around curve, from

posterior side neural arch of 7th cervical to

anterior edge of sacrum, near the median

Li Ge ee fos euceses guoe cu sageteatccenc epee one ee 412 mm. 390
Length of neck measured around curve, from

anterior side neural arch of atlas to posterior

edge neural arch 7th cervical vertebra (near

MMe Citar Miner Gi) esses ee ens See eee, Sanne eee ne Beene 69 110
Ratio length of neck to length of trunk............ 16.74 28.20

This very materially reduced ratio is even less than that of
the seal (Phoca vitulina) which, in a specimen at hand, is nearer
that of the river otter. There is in the sea-otter no evident
elongation of the trunk as is sometimes noted in aquatic animals.

TAIL

The tail shows a tendency toward reduction in the number
of elements, having in our specimen twenty-one vertebrae instead
of the twenty-four which are present in Lutra. Coues asserts**
that Gerrard gives the number of caudal vertebrae as eighteen,
which indicates a still further reduction in the specimen or
specimens examined by him. The Stanford University example
studied by the writer has nineteen caudal vertebrae. The re-
duction in the number of tail elements would not be unexpected,
as the sea-otter uses its hind feet largely for propulsion. In
this respect progression in aquatic adaptation in the sea-otter
tends to parallel. that of the seal, which possesses only twelve
caudal elements. Martin notes*t the fact that in swimming the
hinder extremities are placed far back, exceeding the tail when
stretched out in the act of swimming. The tail is said to appear
placed between them almost as much as it is in the seals.

The flatness of the tail of Latax when viewed from above
suggests that the organ is used as a means of elevation and de-
pression of the head while swimming, and as a directive organ.
Probably it assists also in diving. Snow (loc. cit.) says that

33 Coues, E., op. cit., p. 831.
34 Martin, W. C. L., op. cit., p. 59.

1914] Taylor: Aquatic Adaptation in the Carnivora 483

the tail is used as a rudder. The shape of the tail and the
presence of the so-called flanges upon it laterally have led to
the suggestion by Lull*®® that they are homologous to the ex-
panded flukes on the tails of certain of the Cetacea and Sirenia.
the posterior position of the flukes in these groups being a mech-
anical adaptation which has been accelerated in its appearance
so as to be embryonic.

VERTEBRAE
General Characters.—The form of the vertebrae in the sea-
otter is different from that in the river otter, in that the inter-
vertebral foramina are larger, especially posteriorly, the zyga-

: Y 8
vee
AU eB

Figs. 7-9. Lateral views of selected vertebrae of river otter, sea- otter,
and seal. x.

Figs. 7a, 7b and 7c. Vertebrae of river otter (Lutra canadensis). Fig.
Ta, fifth cervical; 7b, third lumbar; 7c, fourth caudal.

Figs. 8a, 8b and 8c. Vertebrae of sea-otter (Latax lutris nereis). Fig.
8a, fifth cervical; 8b, third lumbar; 8c, fourth caudal.

Figs. 9a, 9b and 9c. Vertebrae of seal (Phoca vitulina). Fig. 9a, fifth
cervical; 9b, third lumbar; 9c, fourth caudal.

35 Lull, R. 8., ‘‘Relation of embryology and vertebrate paleontology,’’
Popular Science Monthly, vol. 77 (1910), p. 153.

484 University of California Publications in Geology [Vou.7

pophyses are nowhere developed to the extent that they are in
the river otter, and the anapophyses are much reduced. The
anapophyses are present on the first lumbar vertebra, indicated
in the second, but practically obsolete in the third. The same
elements are indicated as rudiments even on the third, fourth
and fifth lumbar vertebrae in the mounted skeleton at Stanford
University.

In Lutra the anapophyses are well developed on every lumbar
vertebra but the fifth and sixth. Posteriorly in the sea-otter the
metapophyses are reduced. The bodies or centra of all the verte-
brae are, as compared with those of the river otter, shorter antero-
posteriorly relatively to length of trunk, and relatively higher.
The zygapophysial facets are much reduced, and the epiphyses
are developed much more highly; to such a degree, in fact, that
the heads of the anterior eleven pairs of ribs articulate, not on
the bodies of the vertebrae proper, but on the epiphyses between
them.

There is apparently much greater flexibility in the vertebral
column of the sea-otter, the vertebrae being not nearly so firmly
locked together. The vertebrae show considerable resemblance to
those of the seal, in which the zygapophyses are much redueed, the
intervertebral foramina are large, there are no anapophyses, the
bodies of the vertebrae are short anteroposteriorly, the spinous
processes are very much reduced, and the epiphyses are prominent
(a similar though lesser tendency to have the anterior pairs of
ribs articulating on the epiphyses alone being apparent).

Sacrum.

Zygapophyses are not noticeable upon the sacrum
of the sea-otter, while on the river otter they are indicated. The
transverse process on the posterior sacral is much reduced in
Latacr.

Chevron.—There is no chevron in the sea-otter. Its position is
indicated by two knobs diminishing gradually in size distally, first
appearing ventrally on the seventh caudal vertebra and disappear-
ine as such about the eighteenth. In the river otter the chevron
first appears on the fourth caudal, where it forms a complete or
nearly complete ring. It is definitely arched upon the next two
or three vertebrae, and then gives place to two knobs, gradually
diminishing in relative size toward the distal end of the tail.

1914] Taylor: Aquatic Adaptation in the Carnivora 485

Relation of Vertebral Characters to Aquatic Adaptation.—Re-
duction of interlocking processes, shortening and heightening of
the centra, enlargement of the intervertebral foramina, and
thickening of the epiphyses seem all to be correlated with an
increased flexibility of the vertebral column, which is an adapta-
tion to life in water. Other aquatic animals, as the pinnipeds
and ichthyosaurs, exhibit modifications of the same kind.

Reduction of vertebral processes for muscle attachment may
also be an adaptation to aquatie life, in that an animal living in
water depends largely on flotation for support, as elsewhere ex-
pressed. This would lead to a weakening of muscles otherwise
needed for support and of the processes for their attachment.

The absence of the chevron in the sea-otter may be related
to the shape of its tail, which is flattish dorsoventrally, and to
the reduction in importance of the tail. The tail of the seal
presents no haemal elements. The evolution of the tail of the
sea-otter apparently is following the same direction as_ that
already taken by the seal.

The porpoise (Phocaena) shows tail development in another
direction. In this genus the tail is short, but there are lateral
flukes. There are prominent chevrons on the caudal vertebrae,
which doubtless have a supporting function through their serving
as places of muscle attachment.

In the sea-otter the loss of the chevron seems to be related to
aquatic adaptation through its correlation with the shape of the
tail and its reduction in length. In the porpoise the retention
of the chevron and even its further development is apparently
an adaptation to aquatic hfe, through its correlation with the
probable continued increase in importance of the tail as a pro-
pelling organ.

SCAPULA

The scapula in Latar lutris nereis (no. 6956) is relatively
smaller than in the river otter, and not so long anteroposteriorly.
The distal narrowing is more marked. The spine is not so
prominent, and the acromion is less expanded. The Stanford
University specimen has the acromion and spine more developed
than in no. 6956. The spine of the scapula in the seal is reduced,
and the acromion is still less developed than in the sea-otter.

486 University of California Publications in Geology (Vou. 7

These modifications are indicative of adaptation to life in
the water, in that an animal living in the water does not depend
so much upon its fore limbs as upon flotation for support. This
lack of need of a supporting function allows a weakening to take
place first in the muscles of the fore limbs, and then in the pro-
cesses for their attachment. J. C. Merriam*® found the scapula
in the later Jurassic ichthyosaurs to be narrowed distally, and
suggests that this character may be ascribed to the effect of
aquatic adaptation.

Riss
The ribs are heavy as compared with those of Dutra. This
may be an adaptation to life in the water, since it may be desir-
able for the ribs to have increased weight so as better to resist
the pressure of the denser medium.

PELVIS

The pelvis is elevated somewhat so as to lie more nearly
parallel to the vertebral column than in the river otter. The ilia
are very markedly turned outward anteriorly. Their superior
borders or crests serve as places of attachment, at least partially,
for the following muscles of the hind limb: the gluteus medius,
gluteus minimus, and sartorius. The sartorius is the largest
and probably the most important of these muscles. Its action
is the adduction and rotation of the femur and the extension
of the tibia. It is noteworthy that the proximal portion of
the crest of the tibia, to which the sartorius is fastened, is more
roughened in the sea-otter than in the river otter. The pubic
bones are not (in no. 6956) joined along the symphyseal line,
except by cartilage, but they would possibly become somewhat
more intimately united as the age of the animal increased. The
Stanford University specimen, although a middle-aged adult, still
shows the pubie bones not ankylosed. This fact would indicate
that this is the normal condition in Lataz.

In the seal the pelvis is approximately parallel to the ver-
tebral column, the ilia flare outward anteriorly, so as to be nearly

36 Merriam, J. C., ‘‘Triassic ichthyosauria, ete.,’? Mem. Univ. Calif.,
vol. 1 (1908), p. 75.

1914] Taylor: Aquatic Adaptation in the Carnivora 487

at right angles to the rest of the innominate, the pelvis is rather
loosely connected to the sacrum, and the pubic bones (in the
adult animal) are not united except by cartilage, the symphyseal
line being extremely short.

Figs. 10-12. Pelves of river otter, sea-otter, and seal. XM.
Fig. 10. Lateral view pelvis of Lutra canadensis.
Fig. 11. Lateral view pelvis of Latax lutris nereis.
Fig. 12. Lateral view pelvis of Phoca vitulina.

Relation of Characters of Pelwis to Aquatic Adaptation.—
With the increase in importance of the hind limb as a paddle,
the muscles for the adduction and rotation of the femur and
extension of the tibia would augment in size. Several of the
muscles, as above indicated, are attached to the superior border
of the ilium; so the flare of this part of the bone may be readily
accounted for as being a natatory modification.

488 University of California Publications in Geology (Vou. 7

In aquatic animals inereased flexibility of the vertebral
column is associated with a pelvis having a position more nearly
parallel to the vertebral column than in land forms. The pelvis
is also more extended posteriorly, and has a looser connection
with the sacrum and weaker pubic symphysis. The sea-otter
shows all these characters to a small extent.

The characters of the pelvis which serve to differentiate it
from that of the river otter are thus clearly related to aquatic
adaptation.

Fore LIMBS

The fore limbs in Lataxr are proportionately smaller than in
the fluviatile form of otter. The humerus is not so compressed
laterally. The space between the radius and ulna is slightly
ereater than in the river form. The metacarpals and phalanges
are reduced. The tuberosities for muscle attachment, while not
prominent, would probably become more so as the animal grew
older, and so are probably not significant from the standpoint
of aquatic adaptation. The head of the humerus is pushed back
with reference to the shaft of the bone, so that the fore limb has
a slightly more posterior position than in the river otter. In the
seal the humerus, radius and ulna are much shortened, and the
head of the humerus is pushed still farther back, the articular
surface, instead of being at right angles approximately to
the shaft of the bone, being more nearly parallel to it, giving the
limb a still more posterior position. The olecranon of the ulna
is, in the sea-otter, slightly less prominent than in the river
animal, which modification is associated with the general reduc-
tion in the size of the limb. The metacarpals resemble the
phalanges. In Latar as in Lutra, the fifth digit of the forefoot
is longer than the first.

In the seal the forefeet serve mainly as paddles, while in the
sea-otter the almost unanimous testimony of observers is that they
serve as organs of prehension as, for example, holding food or
the young.

The principal organs used by aquatic groups for locomotion
through the water are (1) posterior paddles, as in the seals, or
(2) a seulling tail, as in whales. The sea-otter evidently makes

1914] Taylor: Aquatic Adaptation in the Carnivora 489

use of the former. Apparently the uses to which the sea-otter
puts its forefeet do not require a large hand. If, as the available
evidence seems to indicate, the fore limbs are little used in pro-
pulsion, a certain reduction in size would be beneficial to the
species, and this reduction would be in the nature of an aquatic
adaptation.

Hinp Limes

The hind limbs present more evident adaptations than any
other part of the skeleton. These adaptations may be set down
as follows: (1) Proportional abbreviation of the propodial and
epipodial portions of the limb; (2) curvature or backward ex-
tension of the limb; (3) distal dilation of the limb; and (4)
elongation of digits. Under the first head it should be noted that
the femur, tibia and fibula are relatively short. The anterior
surface of the femur is longer than in Lutra, causing the distal
articular surface to face more posteriorly. This imples a greater
backward extension of the hmb. As an evidence of distal dila-
tion, it may be noted that the feet are lengthened and widened
to form oars, or paddles. This dilation is brought about largely
by the elongation and spreading of the digits. The abbreviation
and backward extension of the limb shows a tendency in the
development of the hind limb to parallel that of the fore limb,
though the disposition toward a distal dilation opposes this
tendency.

There is no ligamentum teres in the sea-otter, and consequently
no pit in the head of the femur for its reception. This is another
evidence in the parallelism of the development between the sea-
otter and the seal, in which there is likewise no ligamentum teres
or pit in the femur for its attachment. The environmental
medium is of such a nature that apparently it does not require
so strong a connection between pelvis and femur as does the
medium of the atmosphere. Increased freedom of movement
may be subserved by this looser connection, and it is probable
that this would be an advantage. Flexibility of the vertebral
column, as has already been mentioned, is an aquatic adaptation.

In the hind limb of the seal modifications analogous to those
in the sea-otter are apparent. Two opposing tendencies seem to

490 University of California Publications in Geology [Vou.7

Figs. 18-15. Posterior limbs of river otter, sea-otter and seal. x4.
Fig. 13. Posterior limb of Lutra canadensis.
Fig. 14. Posterior limb of Latax lutris nereis.
Fig. 15. Posterior limb of Phoca vitulina.

1914] Taylor: Aquatic Adaptation in the Carnivora 491

have existed in its evolution, namely, that toward shortening of
the limb, and that toward backward extension of the limb. The
first tendency has brought about the shortening of the femur, but
the second has resulted in the epipodials remaining rather long.
Distal dilation has resulted from an elongation and lateral spread-
ing of the digits.

Elongation and distal dilation of the hind foot is differently
brought about in the sea-otter and seal. In the former the fifth
digit is the longest, the first being the shortest, and those between
grading regularly from one to the other. In the latter the first
digit is the longest, the fifth being next, followed by the second,
third and fourth. The region in which expansion would be ex-
pected to occur is the outside of the foot, that is, on its posterior
margin, the region of the fifth digit. In those aquatic animals
which exhibit hyperdactyly, it is often the fifth digit which is
spht. The extension of the swimming membrane calls for the
extra support on the posterior margin.**

The foot of the sea-otter is of such a form that this extra
support is furnished through the fifth digit being longest. In
this connection the following facts might be regarded as indi-
eating that Latax is derived from a form near the existing river
otter. Lutra canadensis has the first digit shortest, second and
fifth about equal, the fifth a little the longer, and the third and
fourth about equal. A considerable elongation of the fifth, and
a slight lengthening of the fourth, would bring about the relations
existent in the hind foot of the sea-otter.

STAGE OF EVOLUTION OF LATAX

Latax has probably already attained to as great a degree of
structural adaptation to hfe in the water as is possible without
some modification in function of some of the various parts. This
change in function would be conditioned by a change in habits.
Following out the suggestions already presented it is conceivable
that, by coming to feed on fish and pelagic cephalopods, thus
attaining greater independence of shore animals, the sea-otter
might, in time, become entirely pelagic in habitat. In such an

37 Osburn, R. C., ‘‘ Adaptive modifications,’’ Ann. N. Y. Acad. Sei.,
vol. 16 (1906), p. 456.

492 University of California Publications in Geology [Vou.7

event its teeth might attain a form more like those of a seal (i.e.,
approach the conical type), its cranium might increase still
further in size, its neck become shorter, the tail be reduced, and
other changes in the skeleton take place.

Phoca evidently represents a considerably more advanced
stage of adaptation to aquatic life than Latar, for it has devel-
oped the habits and corresponding adaptive characters whereby
it may live at times in the open seas independent of shore forms.
As has been suggested, there is some evidence that Lataxr also
has the ability to live far from land.

The following characters are illustrative of the sort of modi-
fication which is shown particularly well by the seal, adaptation
of its teeth to a piscivorous diet, modification of its fore and hind
feet to serve as paddles, abbreviation of the tail, and flexibility
of the vertebral column. Modification in form of almost every
bone in the skeleton has taken place so as to carry on with greater
efficiency some new function in the new environmental medium.
The same statement is true of the sea-otter, though, of course,
the modification is less in amount.

PALAEONTOLOGIC EVIDENCE BEARING ON PROBLEM OF
ORIGIN OF SEA-OTTER

Our knowledge of the history of the Mustelidae in general and
the Lutrinae in particular is so limited that it is impossible to
point out at this time where the sea-otter first appeared.

Lydekker has remarked** that the distribution of fossil Mus-
telinae accords well with present-day distribution of the living
species. So far as is known to the writer, this may be said of
the lutrine division of the Mustelidae also. It is therefore not
improbable that Latar is descended from some primitive form
that lived in North Ameriea or Asia, since Latar is found at
present in the waters of the Pacifie Ocean only.

The evident agreement in skeleton between Latax and Lutra
suggests that the sea-otter is an offshoot from the lutrine stock
after it had become differentiated as such. The fundamental
consonance of characters, as illustrated especially in the denti-

38 Lydekker, R., ‘‘Siwalik and wWarbada carnivora.’’ Palae. Ind., Cal-
cutta, series 10, vol. 2 (1884), p. 179.

1914] Taylor: Aquatic Adaptation in the Carnivora 493

tion, militates against the idea that Lataz is of independent origin.
If the sea-otter is derived from some form of otter immediately
ancestral to the Recent Lutra, it would presumably not date back
earlier than Pliocene or late Miocene time. As the genus Lutra
is known to have occurred in North America as early as the
Miocene, it may easily be the parent stock.

Enhydridon® or Enhydriodon from the Lower Pliocene of
Asia (Siwalik beds, India) possesses teeth which are interme-
diate in their crowns between Lutra and Latar. The superior-
tooth formula is the same as in Latar. Enhydriodon may lhe
somewhere near the line of ancestry of this genus, although its
geographic location might argue against its actually being ances-
tral to the sea-otter. It may represent a form which, in another
part of the world, had started to specialize in the same direction
as that followed by the sea-otter.

VARIATION IN LATAX

Under this head two conclusions seem obvious: (1) The
variation in the sea-otter has been away from Lutra; (2) The
variation in the sea-otter is intimately related to aquatic
adaptation.

It will be remembered that 69.6 per cent of the most im-
portant differences between Latax and Lutra are shown to be
related to aquatic adaptation. Doubtless, if our knowledge were
greater, other characters would be seen to be so related also.

In general a slow change through continuous variations is seem-
ingly indicated both by the nature of the characters separating
the sea-otter from the terrestrial form, and by probable analogies
with the development of other species of mammals as appre-
hended through a contemplation of certain palaeontologie phyla.
The differently shaped skull in Latar, such that the anterior ends
of the nasals are almost directly above the anterior ends of the
premaxillaries, the different degree of development of the para-
conid of the lower carnassial, the modification in the form of
the zygapophyses, and the slightly different size of the olecranon,
are some of the characters which would seem to indicate this

39 Beddard, F. E., ‘‘Mammalia,’’ in Cambridge Natural History (New
York and London, The Maemillan Company, 1902), vol. 10, p. 489.

494 University of California Publications in Geology [Vou.7

slow change through continuous variations. On the other -hand,
the differences in tooth formula and in the number of caudal
vertebrae may indicate meristie variation, integral, and so dis-
continuous.

According to Darwin: ‘‘A strictly terrestrial animal, by occa-
sionally hunting for food in shallow water, then in_ streams or
lakes, might at last be converted into an animal so thoroughly
aquatic as to brave the open ocean.’’*? We look at the highly
specialized sirenian and cetacean, and it is difficult to realize
how its present form could have been reached through gradual
transition from a primitive land-living to a highly specialized
aquatic form. Darwin" realized, of course, the difficulties for
his own natural selection hypothesis involved. Nevertheless he
believed that, although the end product of the evolutionary pro-
cess might be widely different from its parent land form, still
each stage in the transition of the organs involved might be useful
to its possessor. This study of the sea-otter surely does not con-
flict with at least this much of Darwin’s view.

It may further be stated that many of the facts as brought
out in this study might indicate that the evolution has resulted
from a combination of methods, and that Whitman’s suggestion*?
as to the probabilities of the reconciliation of natural selection,
orthogenesis and mutation may be as near the truth as it is
possible to come at this time.

The imperfection of the geological record will probably always.
be an obstacle to the tracing through of all stages of aquatic
adaptation in a single mammalian phylum. We may consider
ourselves fortunate if we are able to approximate these stages in
different groups. This we seem to be able, in a measure, to do.
Within the Mustelidae we have examples of animals entirely ter-
restrial (as Gulo, Martes, and Mephitis) ; one genus which lives a
terrestrial and river life (Lutra); and one which is almost ex-
clusively marine (Lataxr). In the reptilian order Ichthyosauria,

40 Darwin, C., Origin of species (ed. 6 reprint; New York, Peter
Eckler, 1859), p. 200.

41 Darwin, C., ibid., p. 155.

42 Whitman, C. O., ‘‘The problem of the origin of species. Congress of

Arts and Science, Universal Exposition, St. Louis (Boston and New
York, Houghton, Mifflin & Co.), vol. 5 (1904), p. 44.

ys)

1914] Taylor: Aquatic Adaptation in the Carnivora 495

there are illustrated several stages in the adaptive process, rang-
ing from the less specialized genera Phalaradon and Mixosaurus
to the more specialized Cymbospondylus and the most specialized
Baptanodon. Thus we are able to contemplate a series of begin-
ning stages of aquatic adaptation, in a terrestrial to littoral-
marine group, on the one hand, and a series of advanced stages
in a group exclusively marine, on the other. Although the gap
which intervenes is considerable, the pinnipedian carnivore Phoca
exemplifies a stage of adaptation probably somewhere between the
two series, and as palaeontological exploration is carried forward
it is not unlikely that more intermediate stages will be discovered.

SUMMARY

The following points covered in this paper may be broadly re-
capitulated :

1. The detailed consideration of the osteology of Latax and
Lutra emphasizes, first, the close relationship of the two, in that
both are fundamentally alike, having probably descended from
a common ancestral form; and second, the fact of the divergence
of the former from the latter, the bulk of the modifications in
skeletal structure being clearly and intimately related to adapta-
tion to life in the water.

2. The facts pertinent to the palaeontologic history of Latax
indicate its descent from a lutrine ancestor, probably near the
genus Lutra.

3. The consideration of this conerete case of a species appar-
ently in a stage of evolution transitional between a form of ter-
restrial and one of marine habit cannot be shown to favor one of
the proposed methods of evolution to the exclusion of others.

4. This study suggests a most significant possibility, namely
that in mammals, during the transition between a land and water
habitat, a crushing type of dentition is likely to be found. <A
broad dentition, fitted only for crushing, may, in other words,
be intermediate between the more compressed and acutely tuber-
culated cheek-teeth of land-dwelling forms in which a dental
armature fitted for cutting and tearing is a necessity, and the
more nearly isodont cheek-teeth of marine-dwelling forms in
which the dentition serves no other function than that of catch-
ing and holding.

INDEX*

Aelurodon, origin of, 371.

Aeolian ablation, 332.

Agglomerate, 325.

Alexander, Miss Annie M., acknowl-
edgment to, 467.

Allen, J. A., cited, 96.

Alluvial Fan Formations, Petro-
graphic Designation of, 325.
Alluvial fans, 326; dissection of, 141;
at Battle Mountain, Nevada, 328;
term ‘‘fanglomerate’’ proposed

for, 330.

Anchitheriine Horses, New, from the
Tertiary of the Great Basin
Area, 419.

Anchitherium (?) zitteli, 433.

Anderson, Frank M., cited, 169, 197,
207, 224, 243.

Anderson, Robert, cited, 192, 212,
219, 220, 228.

Antler, a Peculiar Horn or, from the
Mohave Miocene of California,
Son:

Apatite, 16.

Aplodontia major fossilis, 157.

Aquatic Adaptation, The Problem of,
in the Carnivora, as Illustrated
in the Osteology and Evolution
of the Sea-Otter, 465.

Archaeohippus ultimus, 428.

Architectonica weaveri, 287; figures
of, opp. 296.

Arctomys daviventer, 154.

Arctotherium ecalifornicum, 41, 78.

simum, 40, 41, 70.

Argentite, 7.

Arkose, 331.

Arnold, Ralph, cited, 182, 183, 186,
188, 189, 192, 200, 2038, 208, 212,
216, 219, 350.

Arsenates, 16.

Ashley, G. H., cited, 204.

Astyris, 283; figure of, opp. 294.

Auchenia hesterna, 318.

vitikeriana, 322.

Avian Palaeontology, Contributions
to, from the Pacific Coast of
North America, 61.

Azurite, 15.

Baker, C. L., 117; cited, 420, 444.

Baptanodon, 495.

Barite, forms and measurements, 18.

Barrell, J., cited, 330.

Basin Ranges, Nevada, 329.

Battle Mountain, Nevada, 328; fan-
glomerate, 332; Triassic rocks,
333.

Beal, C. H., 243.

Becker, G. F., cited, 195.

Belmont mine, Tonopah, Nevada, 7,
9.

Berkeley Hills, California, 199.

Bittium longissimum, 289.

Black Mountain, California, 119; oli-
vine basalt on, 126.

Blake, W. P., 144; cited, 170, 193.

Branner, J. C., cited, 216, 269.

Breccia, 325, 326; fault-breceia, 325.

Brown, Barnum, cited, 79.

Bryant, H. C., acknowledgment of
assistance, 469.

Buek, T. H., 420.

Buena Vista Lake, California, 414.

Burgess, J. A., cited, 1.

Buwalda, J. P., 335, 375, 381, 420,
443.

Cacoxenite, 17.

Calcite, 14; forms and measurements,
15.

Caliche, 332.

California Academy of Sciences, 169,
268.

California Museum of Vertebrate Zo-
ology, 158, 468.

Calliostoma (?) arnoldi, 288.

Callospermophilus ehrysodeirus, 156.

Camelops hesternus, figures of skulls,
307, 318.
kansanus, figures of, 317.
near hesternus, figures of skull, 309,
311, 314.
Camels, in Pleistocene, 305.
Campbell, M. R., cited, 444.
Caneellaria irelaniana, 282; figure of,
opp. 294.
stantoni, 282; figures of, opp. 294.
Canid Genus Tephrocyon, Notes on,
359,

* Univ. Calif. Publ. Bull. Dept. Geol., vol. 7.

Canis, origin, 371.

Cantua-Panoche district, California,
220.

Carbonates, 14.

Carearhinus antiquus, 248.

Carcharias clavatus, 249.

morricei, 249; figure of tooth, 255.

Carcharodon arnoldi, 252.

megalodon, 251.
riversi, 252.

Care@horodon rectus, 252.

Cardium dalli, 289.

Caricella stormsiana, 287, figures of,
opp. 296.

Carmelo Bay, California, 185.

Carnivora, The Problem of Aquatic
Adaptation in, as Illustrated in
the Osteology and Evolution of
the Sea-Otter, 465.

Carnivora, Recent Discoveries of, in
the Pleistocene of Rancho La
Brea, 39.

Castor subauratus, 155.

Cat Cafion, California (Cafada del
Gato), 23.

Cathartidae, distribution, 85.

Cedar Monntain beds, Nevada, 384.

Cerargerite, 3, 9.

Cetacea, 466, 483.

Chagoopa Plateau, possible correlation
with Ricardo erosion surface, 137.

Chaleopyrite, 8.

Chert in the Monterey series, 236.

Cinnabar, 8.

Citellus beecheyi captus, 164; figure
of skni, 165.

douglasi, 155.

Clark, B. l., 47; cited, 232.

Clark, F. C., 350; acknowledgment of
assistance, 62, 110, 115.

Clavella tabulata, 283; figure of, opp.

294,
Cliff talus. See Talus.
Climatie conditions, in Pleistocene

times, 108; change in, 456; dur-
ing accumulation of Marysville
3uttes Eocene, 267.

Coalinga oil district, California, 207,
219.

Coalinga-MeKittrick region, Califor-
nia, 214.

Coast Ranges, middle, 199; southern,
197, 207.

Condon, Thomas, palaeontological col-
lection of, 362.

Conglomerate, 327; Gila Conglomer-
ate, 327.

Cook, cited, 12.

Cook, H. J., cited, 310, 328, 364, 370,
871.

Index

[498 ]

Cooper, J. G., 258; cited, 259, 265,

267.

Cope, E. D., cited, 64, 65, 87, 94, 313,
321, 322.

Cordiera gracillima, 280; figure of,
opp. 294.

Crystals from Tonopah, Nevada, fig-
ures of, following p. 20.

Cuprite, 13.

Cymbospondylus, 495.

Cyphornis magnus, 66.

Dall, W. H., cited, 173, 272.

Darwin, C., cited.

Debris slopes, dissection of, 141.

Dentition, typical measurements, 409.

Dermal ossicle, 350.

Dickerson, R. E., 257; cited, 49, 381.

Diller, J. 8., cited, 173.

Dipoides, figures of, 382.

lecontei, 382; figures of, 382.

Dixon, cited, 234.

Drillia ullreyana, 277; figure of, opp.
292.

Drymohippus, 420.

Eakle, A. 8., 1.

Eastman, C. R., cited, 101.

El Paso Range, California, 119, 436,
440; rocks of, 121, 142; lava
flows, 123; flank of a fault scarp,
130; hydrometaphorism in, 132;
recent faulting, 136; uplift, 142.

Eldridge, G. H., cited, 182, 1838, 184,
186, 192, 197, 200.

Embolite, 3, 10.

Emmons, cited, 328.

Enhydridon, 493.

Enhydrinae, 471.

Enhydriodon, 493.

Equus caballus, 412.

excelsus, 415.

laurentius, 418.

occidentalis, figures of skull, 399,
401; of mandible, 401; of denti
tion, 405, 409; of mandible with
dentition, 407.

pacificus, 414.

scotti, 416.

Equus zone, 106.

Erethizon epixanthum, 162; figure of
skull, 163.

Eueastor, 583.

Eutamias sp., 156.

Extinction of birds, causes of, 108.

Fairbanks, H. W., cited, 119, 127, 182,
183, 192, 196, 202.

Faleonidae, distribution of, 92.

Fanglomerate, proposed as term for
alluvial fan formations, 329; limi-

tations, 330; coarseness of tex-
ture, 330; facies, 330; varieties,
331; feebly cemented, 332; ce-
mented by carbonate of lime, 332;
searcity among rocks of the past,
333; abundance in arid regions
of North Ameriea, 333; at Battle
Mountain, 332.

Fauna of the Eocene at Marysville
Buttes, California, 257.

Fauna from the Type Locality of the
Monterey Series in California,
148.

Faunal zones, 206, 230.

Feldspar, 15.

Felis atrox bebbi, 48, 44, 45, 78.

Felis, near hippolestes, 42, 43, 70, 73;
figure of mandible, 42.

Fernando formation, California, 23,
181.

Fischer, E. J., acknowledgment of
assistance, 62.

Fossil Lake, Oregon, 78, 414.

Fossil Sharks, Supplementary Notes
on, 243.

Fossils of Rosamond series, Califor-
nia, 126.

Foxen Cafion, California, 23, 24.

Furlong, E. L., cited, 71, 152.

Fusinus (Priscofusus) lineatus, 281;
figure of, opp. 292.

Gabb, W. M., cited, 269.

Gaillard, C., cited, 88.

Galena, 8.

Galeocerdo productus, 247.

Galeorhinus hannibali, 247; figure of
tooth, 255.

Gester, S. II., cited, 448.

Gidley, J. W., cited, 398, 405, 413,
414, 415, 416, 427, 438, 431.

Gilbert, G. K., cited, 119, 327.

Gilbert, J. Z., acknowledgment of as-
sistance, 62.

Glycimeris marysvillensis, 290.

Gold, 7.

Goldman, 4. C., cited, 159.

Grinnell, J., acknowledgment of as-
sistance, 62, 468.

Gulo, 494.

Gypsum, 17.

Haehl, H. L., cited, 203.

Hague, cited, 328.

Haloids, 9; silver, 3-6.

Hamlin, Homer, cited, 189, 192.

Hancock, G. A., acknowledgment of
assistance, 388, 397.

Haneock Ross, Madam, acknowledg-
ment of assistance, 388, 397.

Hannibal, H., cited, 263.

Index

Hawver, J. C., acknowledgment of
assistance, 62.
Hawver Cave, 73.
Hay, O. P., cited, 398, 413, 415, 416,
417.
Hematite, 13.
Hemipristis heteropleurus, 248.
Heptranchias andersoni, 246.
Hershey, O. H., cited, 123.
Hess, cited, 127, 136.
Hinde, G. J., cited, 196.
Hipparion, 376, 440; figures of, 375.
mohavense, n. sp., 436; figures of
upper cheek-teeth, 437.
riehtofeni, 438.
Holden, Ff. H., acknowledgment of
assistance, 469.
Holomeniseus macrocephalus, 322.
suleatus, 321.
Hopper Cafion, California, 187.
Horn, or Antler, A Peculiar, from
the Mohave Miocene of Califor-
nia, 335.
Horses of Rancho La Brea, Prelimi-
nary Report on, 397.
Horses, New Anchitheriine, from the
Tertiary of the Great Basin, 419.

Horses, New Protohippine, from Ter-
tiary Beds on the Western Bor-
der of the Mohave Desert, 435.

Hovey, E. O., cited, 318.

Hiibnerite, 18; forms and measure-
ments, 19.

Hypohippus, 420, 423.

Hypohippus (Drymohippus) nevaden-
sis, 420; figures of molars, 422;
of portions of limbs, 425.

TIehthyosauvia, 467, 494.

Iodyrite, 3, 10; forms and measure-
ments, 11.

Tone formation, 261, 274.

Isurus desori, 251.

hastalis, 250.

Jarosite, 17.

Jasper, O. W., gifts of, 258.

Jones, W. F., cited, 223, 451.

Joplin district, 326.

Jordan, D. 8., 243.

Kane ‘‘dry lake,’
129,

Kaolinite, 15.

Kellogg, Louise, 151.

Kern River region, California, 224.

Kew, William, 268.

Keyes, C. R., cited, 444.

Kirker Pass, 47.

Koken, E., cited, 439.

Kraus, cited, 12.

La Brea. See Rancho La Brea.

California, 120,

Index

Lamna appendiculata, 250.

Latax, 494; distribution, 470; classi-
fication and relationships, 470;
nature of characters separating
it from Lutra, 473; osteology of
skull, 476; dentition, 478; figures
of teeth, 478; carnassials, 479;
evolution of dentition, 480; neck
and trunk, 481; tail, 482; verte-
brae, 483; sacrum, 484; chevron,
484; relation of vertebral char-
acters to aquatic adaptation,
485; scapula, 485; ribs, 486;
pelvis, 486; relation of charac-
ters of pelvis to aquatic adapta-
tion, 487; fore limbs, 488; hind

limbs, 489; ligamentum teres,
489; stage of evolution, 491;
variation, 493.

Latax lutris, 466; figure of skull,
477.

lutris, 468, 470.

nereis, 467, 470; figures, 467, 478;
osteological and dental charac-
ters apparently related to aquatic
adaptation, 473; characters ap-
parently not related to aquatic
adaptation, 475; figures of verte-
brae, 4838; figures of pelvis, 487;
figure of posterior limb, 490.

Lavas of Monterey series, 237.

Lawson, A. C., 325, 378; cited, 138,
144, 195, 199, 215.

Leidy, J., cited, 171, 174, 318, 320,
348, 356, 365, 413, 414, 415.

Lepus, 383.

Lepus klamathensis, 155, 164.

ealifornicus, 163.

Leriche, Maurice, 244.

Limonite, 13.

Lindgren, W., 258; cited, 260, 263,
444,

Lompoe quadrangle, California, 23.

Los Alamos Valley, California, 23.

Los Angeles, California, 211.

Louderback, G. D., 21, 177.

Lucas, F. A., acknowledgment of as-
sistance, 62; cited, 65.

Lutra, 494; nature of characters sep-
arating it from Latax, 473.

canadensis, 467, 468; osteological

and dental characters apparently
related to aquatic adaptation,
473; characters apparently not
related to aquatic adaptation,
475; figures of skull, 477; of
teeth, 478; of vertebrae, 483; of
pelvis, 487; of posterior limb,
490,

Lutrinae, 471.

[500]

McKittrick-Sunset region, California,
221.

McLaughlin, A. C., 248.

“Malachite, 15.

Manealla californiensis, 67.
Manganite, 14.
Manganocalcite, 15.
Manix, California, 444.
Manix beds, map of, opp. 458; plate
illustrations, opp. 460, 462.
Manix Lake, California, origin, 454;
disappearance, 455,
Marsh, O. C., cited, 94.
Martes, 49+.
Martin, Bruce, 148, 169, 172, 268.
Martinez, California, 414.
Marysville Buttes, fauna of Eocene,
257; map of, 262; Cretaceous of,
263; climatic conditions, during
accumulation of Eocene of, 267.
Matthew, W. D., cited, 310, 323, 364,
370, 371, 424.
Megalonyx, 341.
Megalonyx californicus, 352; figures
of, 353, 354, 355, 557.
Megalonyx zone, 106.
Mephitis, 494.
Mereerat, A., cited, 94.
Merriam, C. H., cited, 84, 109.
Merriam, J. C., 39, 82, 258, 305, 335,
359, 373, 388, 397, 419, 435, 468,
cited, 48, 75; note, 152, 167, 169,
201, 205, 423, 435, 436, 439, 451,
467.
Merychippus, 377; figures of, 375.
Meryeodus, 337.
coronatus, figures of, 336.
necatus, 338; figures of, 338.
Mesozoic of Nevada, 334.
Microtus californicus, 160, 166.
Miller, L. H., 61, 350, 388.
Millis, H. A., acknowledgment of as-
sistance, 248.
Mina, Nevada, 420.
Minerals of Tonopah, Nevada, The, 1.

Mitchell, W. C., acknowledgment of
assistanee, 243.

Mixosaurus, 495.

Mizpah shaft, Tonopah, Nevada, 8;
vein, 14.

Modelo formation, 181; sandstones,
186.

Mohave Desert, California, 119, 435,
443; faulting, 131; peneplain,
137; post-Miocene peneplain, 138.

Mohave fauna, 384.

Mohave Miocene, 335, 427.

Molybdate, 18.

Montana-Tonopah mine, 15, 17.

Monterey Series, The, in California,
Wf

Monterey series, 49, 50, 59; stratig-
raphy of type locality, 145;
nomenclature of depositional fa-
cies, 190; eritical review of
knowledge of, and history of
nomenclature, 193; general de-
scription, 232; sediments, 232;
progress of sedimentation, 233;

effect of geographical conditions

on sediment, 234; depositional

oscillation, 235; chert of, 236;

relation to occurrences of petro-

leum, 226; voleanie products in,
236-237; limits, 237; fauna, 238.

Moody, W., 451.

Moran, Robert, cited, 185.

Moreno, F. P., cited, 94.

Morrice, Charles, gift, 243, 245.
Mosley, H. N., cited, 266.

Mourning, H. §., 335, 420, 427, 444.
Muir, California, 302.

Mustelidae, 471, 472, 494.
Myliobatis merriami, 256; figure of
tooth, 255.

Native eleinents of minerals of Tono-
pah, Nevada, 7.

Natrojarosite, 18.

Neocene Section, The, at Kirker Pass
on the North Side of Mount
Diablo, 47.

Neohipparion, 376, 377; figures of,
375.

plicatile, 438.

Neotoma cinerea occidentalis, 158.

Newark system, 333.

Newark Triassic, 334.

Newsom, J. F., cited, 216.

Nothrotherium and Megalonyx from
the Pleistocene of Southern Cali-
fornia, 341.

Nothrotherium (?), 350; figures, 351.

graciliceps, 342; figures of skull,
344, 346, 349.
shastense, 343:
Nucula cooperi, 290.

Oliverato californica, 286; figures,
opp. 296.

Olivula marysvillensis, 286; figures,
opp. 296.

Opal, 13, 26.

Opal cement in sandstone, 26.

Orindan series, north of Mt. Diablo,
California, 59, 373; plant remains,
383.

Osborn, H. F., cited, 79, 110.

Osmont, Vance, collection of Turri-
tella merriami, 285.

Index

[501 ]

Otter, river, 467.
sea, 466; problem of aquatie adapt-

ation illustrated in osteology and
evolution of, 465.

Ovibos zone, 106.

Oxides, 13.

Pack, R. W., 299.

Palache, Charles, cited, 199.

Panza, California, 300.

Parahippus (?) mourningi, n. sp., 427;
figures, 428, 430.

Peneplain between earlier and later

Rosamond series, 131; of the
Mohave Desert, California, "137,
138.

Perodipus agilis, 167.
Peromyscus gambeli, 166.
maniculatus gambeli, 158.

Peterson, O. A., cited, 365.

Petrographic Designations of Allu-
vial Fan Formations, 325.

Petroleum in the Monterey series,
236.

Phalaradon, 495.

Pharmacosiderite, 17.

Phoea, 495,

vitulina, 468, 482; figures of verte-
brae, 483; figure of pelvis, 487;
figure of posterior limb, 490.

Phos (?) martini, 288; figure opp.
296.

Phosphates, 16.

Physiography and Structure of the
Western El Paso Range and the
Southern Sierra Nevada, 117.

Pinnipedia, 466.

Pinole tuff north of Mt. Diablo, 58.

Plant remains from Orindan, 383.

Playas, 331.

Pleistocene Beds at Manix in the
Eastern Mohave Desert Region,
443.

Pleistocene Bone Deposits of Rancho
La Brea, Recent Observations of
the Mode of Accumulation of,

387.

Pleistocene mammal-bearing lake beds,
443.

Pleistocene Rodents of California,
151.

Pliauchenia (?), 381; figure, 380.

Point Arena district, California, 198.

Point Sal, California, 196.

Polybasite, 8; forms and
ments, 9.

Post-Jurassie granite, 333.

Post-Miocene uplift, two epochs of,

measure-

134.
Potter Creek Cave, 68, 152; rodents
of, 154.

Inder

Pownell, Benjamin, gift, 169.

Procamelus (?), 381; figure, 380.

Prosthennops (?), 378; figures, 378.

Protohippine Horses, New, from
Tertiary Beds on the Western
Border of the Mohave Desert,
435.

Protohippine (?) astragalus, 377; fig-
ure, 377. :

Protohippus (?) tantalus, n. sp., 440;
figure, 441.

Pseudoanticline, 25.

Pseudo-current bedding, 25.

Pseudofolds, 25.

Pseudolaminae, 23.

Pseudomalachite, 16.

Pseudostrata, 23.
Pseudostratification, 22.
Pseudostratification in Santa Bar-

bara County, California, 21.

Psilomelane, 14.

Puente Hills, California.

Pyrargyrite, 9; forms and
ments, 9.

Pyrite, 8.

Pyrolusite, 14.

Quartz, 13.

Quaternary deposits of Nevada,

Rancho La Brea, 39, 75, 152, 305, 387,
397; rodents of, 154, 397; six
plates in illustration of, opp. pp.
394, 396, 398, 400, 402, 404.

Ransome, F. L., cited, 327.

Recent Discoveries of Carnivora in
the Pleistocene of Rancho La
Brea, 39.

Recent displacement in the valley of
the Jawbone Cafion drainage,
140.

Recent Observations on the Mode of

Accumulation of the Pleistocene

Bone Deposits of Rancho La

Brea, 387.

Rock Canon, California, 120;
basalt in walls, 124; origin, 134.
Reed, John T., 444.

Reinhardt, J., cited, 347, 348.

Rhinoptera smithii, 254; figure
tooth, 255.

Rhodochrosite, 15; forms and meas-
urements, 15.

Rhodonite, 16.

Ricardo, Mohave Desert, California,
376; erosion surface, 138; fauna,
385; beds, 436.

Ridgway, R., cited, 96.

River otter, 467.

Rodeo Pleistocene, 82.

measure-

329.

Red

[502]

Rosamond series, California, 121, 123,
384; fossils, 126, 133; materials,
133; age, 142; peneplanation, 142.

Ross, Madam Ida Hancock, acknowl-
edgment of assistance, 388, 397.

Salinas Valley, California, 202.

Samwel Cave, California, 71, 152; ro-

dents, 154, 350.

Clemente Island, California, 196.

Joaquin Hills, 300.

Joaquin Valley, California, south

end, 228.

Luis quadrangle, California, 202.

Mateo County, California, 203.

Pablo, California, 205; series, 48,

50, 52; Lower Division, 58, 59;

fauna, 54; Upper Division, 55

59; faunal zones, 57.

Pablo group north of Mt. Diablo,

52.

San Pedro, California, 200, 350; up-
per San Pedro beds, 350.

Sand pendants, 27.

Santa Barbara County, California, 23.

Santa Catalina Island, California, 196.

Santa Clara Valley, California, 209;
in Ventura County, 180; develop-
ment of region south of, 188;
relationship of Santa Clara Val-
ley region of Ventura County to
the coastal region to the north
and west, 179.

San
San
San

San

Santa Cruz folio, California, 216.
Santa Maria district, California, 212.
Sargent oil field, California, 223.
Schlosser, M., cited, 488, 489.
Sciuropterus alpinus’ klamathensis,
157.
Sciurus douglasi albolimbatus, 157.
griseus fossilis, 155, 156.
Scutaster, 299, 300.
andersoni, 299, 301; figure, opp. 304.
Scutella fairbanksi Merriam, 184.
merriami, 300.
norrisi, 299; figure, opp, 304.
Scutella norrisi and Scutaster ander-
soni, Notes on, 299.
Sea-otter, 466; osteology and evolu-
tion of, 465; history of literature,
469; origin, palaeontologie evi-

dence bearing on problem of,
492; summary of points on
aquatic adaptation of, 495.

Selenium, 7.

Sericite, 16.

Sespe formation, 181, 184; upper

Sespe, 183; phase of the Tejon,
86

Sharks, 243.

Shufeldt, R. W., cited, 65.

Siderite, 15.

Sierra Nevada, southern, 137; eastern
searp, 139.

Siestan beds, 373.

Sigmogomphius, 383.

Silieates, 15.

Silver, 7.

Sinclair, W. J., cited, 102, 152, 157,
159, 169, 170, 348.

Siphonalia sutterensis, 283; figure,
opp. 294.

Sirenia, 466, 483.

Sisquoe Creek, California, 23.

Skull, The, and Dentition of a Camel
from the Pleistocene of Rancho
La Brea, 305.

Smith, J. P., cited, 222, 229, 238.

Smith, W. 8. T., cited, 196.

Smith-Woodward, A., acknowledg-
ment of assistance, 62.

Sphalerite, 8.

Spurr, J. E., cited, 1, 10.

Squatina lerichei, 253; figure of tooth,
255.

Stearns, R. E. C., cited, 273.

Starks, E. C., 468.

Stephanite, 9.

Stewart Valley Miocene, 420.

Stock, Chester, 341.

Stone Cafion Mine, California, 300.

Stoner, R. C., 387.

Storms, W. H., acknowledgment of
assistance, 259; cited, 444.

Stratification, meaning and origin, 21.

Sulphantimonites, 8.

Sulphates, 17.

Sulphides, 7.

Suman, J. R., petrographic descrip-
tion of olivine basalt, 127.
Summerland district, California, 212.
Sureula clarki, 278; figure, opp. 292.
crenatospira, 278; figure, opp. 292.
davisiana, 279; figures, opp. 294.

holwayi, 279; figure, opp. 292.

Swarth, H. S., acknowledgment of
assistance, 62.

Sylvilagus auduboni, 164, 167; figure
of tooth, 165.

bachmani cinerascens, 168.

Synechodus, 274; figure.

Talus, 326; cliff, discrimination of,
from alluvial fan accumulations,
331.

Tapir Remains from the Late Ceno-

zoic Beds of the Pacific Coast
Region, 169.

Index

Tapir specimen from Cape Blanco,
Oregon, 172.
Tapirus haysii californieus, 170.
near haysii californicus, un. subsp.,
173.
Tar Creek, California, 184.
Taxidea taxus, 468.
Taylor, W. P., 155, 465.
Tellina sutterensis, 290.
Temblor basin, California, 226.
Tephrocyon, Notes on the Canid
Genus, 359.
Tephrocyon, 360; figures, 369, 370.
hippophagus, description, 364; fig-
ures, 365.
kelloggi, description, 367; figures,
368.
near kelloggi, figures, 368.
rurestris, 362; figures, 363, 364.
temerarius, description, 365; fig-
ures, 366, 367.
Terebra wattsiana, 281; figure, opp.
292.
Tertiary faulting, 329.
Tetrabelodon (?), 381.
Tetrahedrite, 9.
Thalattosauria, 467.
Thomomys bottae pallescens, 165,
167.
leucodon, 161; figures of portion
of skull, 161.
microdon, 160; figures of portion
of skull, 161.
Thousand Creek beds, Nevada, 384.
Tonopah, Nevada, minerals, 1; gene-
sis of, 1; description, 7.
Topatopa formation, 181.
Topatopa Range, California, 180.
Trask, J. B., eited, 195.
Triassic rocks, Battle Mountain, 333.
Trochoecyathus (?) perrini, 291.
Tyron, G. W., cited, 266.
Tuffs of Monterey series, 236.
Tungstate, 18.
Tuolumne County, California, 414.
Turner, H. W., 258; cited, 260, 263.
Turquois, 17; Turquoise.
Turris andersoni, 275; figure, opp.
292.
inconstans, 276; figure, 292.
monolifera, 275; figures, opp. 292.
perkinsiana, 277; figure, opp. 292
suturalis, 276; figures, opp. 292.
Turritella merriami, 285; figures, opp.
296.
Type locality of Monterey series, stra-
tigraphy, 145; correlation, 149.
Upper San Pedro beds, 350.
Ursus, sp., 40, 41, 170, 178; figures
of atlas, 40, 41.

Index

Valley View vein, Tonopah, Nevada,
GolO SG:

Vaqueros deposition, opening of, 183;
formation, 181.

Vaqueros-Modelo series, upper part,
181, 186.

Vaqueros-Monterey series of Monte-
rey-Santa Barbara coastal region,
182; development of, 188.

Vaughan, T. W., cited, 266.

Vertebrate Fauna of the Orindan
and Siestan Beds in Middle Cali-
fornia, 373.

Virgin Valley, Nevada, 423.

Voluta lawsoni, 284; figures, opp. 294.

Wad, 14.

Walker Lake, Nevada, 419.

Watts, W. L., 258, 265; cited, 184,
258, 263.

Wavellite, 16.

Weaver, C. E., 48; collections of
Eocene of Washington, 268.
West End mine, Tonopah, Nevada, 8.

Whitman, C. O., cited, 494.

Whitney, J. D., cited, 170, 195.

Winge, O., cited, 88.

Wolframite, 18.

Wortman, J. L., cited, 315, 318.

Wulfenite, 18, 19; forms and meas-
ments, 20.

Yates, L. G., cited, 318.

ERRATA

For Carehorodon read Carcharodon.
For H. H. Cook read H. J. Cook.

Page 39. For Felix read Felis.

Page 54. For Platydon read Platyodon.
Page 252, line 9.

Page 310, footnote.

Page 420, line 1.

[504]

For Lawrence C. Baker read Charles Laurence Baker.

eee en enaemennennesens

{ ral, by George Davis Een a
al is iby. alter Cy Blasdale. sat oi.) ee

mary Felidae from California, by John F. Bovar
Vv na8 of the ee Daye Region, by John, C. Merriam and William

Myriopods ‘and aes of California, by Fordyce Grinnell, Jr...
Osteology of the Thalattosaurian ‘Genus Nectosaurus, by John C.

nerals, by Arthur S. Eakle..
of Fossil Mammals from Virgin ee Nevada, by Jam

(NC se cd a OIRO aaa ME gh OO RRO aN ML kad hc
aphy Faeae Palsaont ogy of the San Pablo Formation = Middle CEM ee

arles_ 15, SHIGI& = Sok aS MRIS ER Be aed ean ae NG
ehinoids from the Tertiary of California, by Charles E. Weaver ..
chinoids from the Tertiary of California, by RB. W. Pack. .cceccccccccsecse----.
ornicus, a Fossil Peacock from wie eee Asphalt Beds of Ranch
by Loye Holmes Miller . Spee cosecnsecnsenceancnennensecnenssnnsenseonreetneenessnssnssnseneenecnenseanenets

an Genus, from Rancho La Breas by Loye Holmes Miller eh
currence of. - Strepsicerine Antelopes in the Tertiary of Northwestern
a, by. John ©. IIS ME Ts ease SE oe eh eee mare oR eek asec
, Its Paragenesis and Mode of Gapiarccs = George Davia Louderback,
peers nee by Nae: C. Blasdale ee eee pa ee te as

1é i the tate “Wertiaty Beds at Virgin Valley «
ygaouisen Kellogg en cacy eg Se

<rh lemennensen

Po SN.” gt MORIN 6:

imitates of Batelib La Brea, by Loye Fal Willor Feet ss ae
mal Beds of Virgin Valley and Thouse? © ¢04 io ovthwestern
John C. Merriam. Part IL—Geologic H « ‘ EA ae
f the eget oil Field, by William F Be SE MEAS

ny: of the Sierra cease Wovtheast € Lake AOx John A. Reid
Gigantic Bear from the Pleistocene of Kaxche Le Greay by, John C.

n of | Mammalian Pena from Tertiary” Beds on the Mohave Desert,

Merriam.
}and 7 in one cover 20 Re aM NOU oe EY RS es a

lifornia, yp Arbhiar 19h Wa 6 cect lee pnncc tevin ah geoa Bn on ean

Tarsi from the Pleistocene of Rancho La Brea, by Loye Holmes

ionships of the Marine Saurian Fauna Deseribed from the Triassic
n by Sane, by John ©. Merriam.
ntitio of f Omphalosaurus, by J ge C. Merriam ae Harold Cc, Bryant,

east

| from the oui: a Asphalt Beds of Ranebo Ga Brea bv Loye |

aphic and Faunal Relations of the Martinez Formation to the Chico i
ion North of Mount Diablo, by Roy E. Dickerson -.....-..sss-csessssssse-scessecessones Ee
te, a Variety of Colemanite, and Howlite from Lang, Eas Angeles

from the Pleistocene of Rancho La Brea, i Walter P. Taylor::

y am al Beds of Virgin Valley and Thousand Creek in Northwestern —
, by John C. Merriam. Part I1.—Vertebrate Whunad iil. tke ]

nd A * in. “one OVER oan cobrn acre Netto sige epee Nene ched seep tine Ea ae

15.

“16.
1 l-
18.

be
am

ee
moO pO

', Nothrotherium and Megalonyx irom the Pleistocene of Southern Ca

. The Monterey Series in California, by George Davis Louderback .....
. Supplementary Notes on Fossil Sharks, by David Starr Jordan and Car _

. Fauna of the Eocene at Marysville Buttes, California, by Roy HE. Diel

. Notes on Seutella norrisi and Scutaster andersoni, by Robert w. Pae
. The Skull and Dentition of a Camel from the Pleistocene of Rancho |

. The Petrographie Designation of Alluvial Fan Formations, .
. A Peculiar Horn or Antler from the Mohave Miocene of California, by.

. Notes on the Canid Genus Tephrocyon, by John C. Merriam ..
. Vertebrate Fauna of the Orindan and Siestan Beds in Middle Calif

. Recent Observations on the Mode of Accumulation of the Pleistocen :

. Preliminary Report on the Horses of Rancho La Brea, by John C.
. New Anchitheriine Horses from the Tertiary of the Great Basin

. New Protohippine Horses from Tertiary Beds on the Western Border

. The Problem of Aquatic Adaptation in the Carnivora, as Tween

. Is the Boulder ‘‘Batholith’’ a Laccolith? A Problem in Oreeempee ¢

VOLUME 6—( Continued).

Notes on the Later Cenozoie History of the Mohave Desert Regio

California, by Charles Laurence Baker ..........---2-----c--scesteces-eneeree--n
Avifauna of the Pleistocene Cave Deposits of California, by Loye Ho
A*Fossil Beaver from the Kettleman Hills, California, by Louise K
Notes on the Genus Desmostylus of Marsh, by John C. Merriam ....

19. The Elastic-Rebound Theory of Earthquakes, by Harry Fielding Re
VOLUME 7. E,
1. The Minerals of Tonopah, Nevada, by Arthur S. Hakle ....-.- :
2. Pseudostratification in Santa Barbara Couaty, California, by George
back
3. Recent Discoveries of Carnivora in the Pleistocene ofsRancho La Bre
Merriam
4, The Neocene Section at Kirker Pass on the North Side “Of Mount Di
Me ON ATC oan hcg pen ov cme -senem seu cnapacan> dinae /omcethcne <n saat n a Sasa nee eee
-5. Contributions to Avian Palaeontology from the Pacific ‘Coast of North 4
Mie ELolmigs. Miler ts. <n. —-< ocg- sence steer ech ennggee se eae Penna eee
6. Physiography and Structure of the Western El Paso Range and the So
Nevada, by Charles Laurence Baker. «......0---2-c:e-nss-csupeoss-a-coevueemeus
' 7. Fauna from the Type Locality of the Monterey Series in California, by
8. Pleistocene Rodents of California, by Louise Kellogg .............
9. Tapir Remains from Late Cenozoic Beds of the Pacific Coast Regio
IMPS TIL AIN o.<.n-- Fosse eondes due benetneeyieeqeepndetaet Uaseefechststeat any cbnavaiiyl ass ee ea
10

Jobm- C.=. Merriam: ooo ts as eb cat a ea eee ee

bo (:) 5: eae eam OR IIS eee ie Renn ae ee Uke alee

Ber Guo Oi ee ee oes eS ie ak eles eee

Merriam 93s) ce Bc sie endl.

BVMertie mis a ye

Desert, by John C. ‘Merriam <1... Seek eee Pie
Pleistocene Beds at Manix in the Eastern Mohave Deseri Region,
15516) (0 Ae ee Basan Se meee nM Maruca Nr Kae

ology and Evolution of the Sea-Otter, by Walter P. Taylor ....

VOLUME 8.

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