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California Academy of Sciences 



Vol. II 





Plates I-XXXV. 


Title-page / i 

Contents iii 

No. 1. Cretaceous Deposits of the Pacific Coast. By Frank M. 

Anderson. ( Plates I-XII ) v-lS4 

(Published December 24, 1902) 

No. 2. A Stratigraphic Study in the Mount Diablo Range of Cali- 
fornia. By Frank M. Anderson. (Plates XIII- 
XXXV) 155-248 

(Published December 4, 1905) 

December 30, 1914. 





Third Series 
Geology Vol. II, No. i 

Cretaceous Deposits 


Pacific Coast 


Frank M. Anderson 

With Twelve Plates 

Issued December 24, igo2 


Published by the Academy 



Charles H. Gilbkrt, Chairman 
Joseph W. Hobson William A. Setchell 




Third Series 
Geology Vol. II, No. i 

Cretaceous Deposits 


Pacific Coast 


Frank M. Anderson 

With Twelve Plates 

Issued December 24, 1902 


Published by the Academy 


JAN 14 1203 


This paper is the result of a study begun in 1894 ^pon 
an interesting collection of Upper Cretaceous fossils from 
a new locality in Southern Oregon, locally known as the 
" Forty-Nine Mine," but referred to here as the Phoenix 

The special feature of interest in this collection is the 
large percentage of individuals and species of the genera 
Schloenbachia, Scaf kites, and the aberrant forms of cepha- 
lopods, types for the most part that were unfamiliar upon 
this Coast. The contents of this collection was referred to 
in the May-June number of the Journal of Geology, 1895. 

Since the first visit to this locality almost every year has 
added new and important species from the same place, and 
from a quite similar locality on the opposite and southern 
slope of the Siskiyou Range, near the village of Henley, 
Siskij^ou County, California. These two localities evi- 
dently belong to the same coastal basin of the Cretaceous, 
and are here included in what is called the Oregon Basin. 

From this fauna the study was naturally led to the Chico 
deposits of the Sacramento Valley, and from these to the 
Horsetown and the whole of the Cretaceous. 

In offering this paper for publication the author wishes 
to acknowledge the kindly interest and assistance of his 
instructors and co-workers, Drs. J. P. Smith, T. W. Stan- 
ton, J. C. Merriam, and others, who have shown not only 
professional courtesies, but have aided the work by a 
friendly appreciation and a cooperative spirit. 

The conclusions that have been reached by this study, 
while they may not be final, are nevertheless believed to be 
important in the development of our knowledge of West 
Coast geology, and in the stud}' of the Great Past and its 
biological and physical geography. F. M. A. 

December 17, 1900. 

( I ) Li] December 24, 1903. 




Plates I-XII. 

Part I. page. 

I. Introduction 4 

II. Historical Review 6 

III. Purpose of the Paper 10 

IV. Stratigraphy of the Cretaceous. . 12 

1. Basement Complex 12 

2. The Sacramento Valley 14 

3. The Oregon Basin 17 

4. British Columbia 18 

5. Southern Occurrences 20 

6. Correlation 21 

V. Faunal Changes of the Cretaceous 22 

1. Recognized Diversity 22 

2. Horizons Distinguished 24 

The Chico Epoch 24 

The Horsetozvn Epoch 40 

The Paskenta Horizon 43 

The Sub-Knoxville Horizon 47 

VI. Disturbances of the Period 48 

1. Distribution of the Horsetown Beds 48 

2. The Chico-Knoxville Unconformity 50 

3. The Peridotite Intrusions 53 

4. The Chico Overlap 54 

VII. Correlation of Deposits 55 

1. The Sacramento Sections 56 

2. Equivalents of the Chico 56 

3. Equivalents of the Horsetown 63 

4. Equivalents of the Knoxville 65 

5. Cordilleran Oscillations 67 

VIII. Summary and Conclusions 68 

Part II. 

Descriptions of Species 71 

Literature Cited 127 

Index 130 

Explanation of Plates 132 



Part I. 

I. Introduction. 

The Cretaceous deposits of the Pacific Coast of North 
America, as already known to geologists, lie within a narrow 
continental border mainly to the west of the Great Basin 
and the northern Cordillera. In their north and south 
range the scattered and disconnected occurrences extend 
from Mexico to Alaska and the Arctic Ocean, although they 
do not territorially cover a large region. Represented upon 
a map with other formations, they might hardly be noticed 
except by one looking for them. They are but remnants, 
or even mere traces, of what was once a more extensive 
system of deposits, which in some places have been entirely 
removed, and in others covered by later sediments, and in 
some cases by volcanic flows. One of the largest and most 
noteworthy of these remnants occupies the Sacramento 
Valley in central-northern California, where it occurs in 
unconnected dashes along its borders, in low hills flanking 
the valley upon the east and west. 

Southward in California, the Cretaceous rocks are spar- 
ingly distributed, occurring only at intervals in the Coast 
Ranges, where they either form some of the lesser ridges or 
protrude from beneath ridges of later sediments. In the 
extreme southern portion of the State, and in Lower Cali- 
fornia, they are confined to a narrow belt in the immediate 
neighborhood of the coast, buttressed against the older 
crystalline rocks of the interior. 

Northward in California, and in Southern Oregon, the 
Cretaceous beds are restricted to the larger valleys lying 
among the Klamath Mountains or upon their eastern out- 
skirts; and here, also, they rest upon the older crystalline 
or metamorphic rocks, and are overlaid by Tertiary or 
Neocene deposits largely of fresh-water origin, or by 
Neocene lavas. 

Within the boundaries of the Great Basin, the only 
Cretaceous rocks that have been reported rest in a similar 
manner upon a complex of early Mesozoic and older rocks. 


in part crystalline, and in part metamorphic sediments, that 
make up the mass of the Blue Mountains in northeastern 
Oregon. Their limits have not been ascertained, but they 
appear to flank these mountains upon the west much as they 
do the Sierra Nevada in California; and here, also, they are 
in turn overlaid by fresh-water Tertiary deposits and Neo- 
cene lavas. 

It would appear from what is known of the distribution 
of the Cretaceous sediments south of the Columbia River, 
and of the older basement series that in Cretaceous 
time formed the floor and margin of the sea, that the 
western coast-line of the Cordilleran continent in early 
Cretaceous time was roughly determined by the three older 
mountain groups, — the Sierra Nevada, the Klamath Moun- 
tains, and the Blue Mountain system in northeastern 

It is not yet proved that in later Cretaceous time the sea 
extended along the whole eastern base of the Klamath 
group, thus severing them wholly from the mainland, with 
which they had previously been connected. 

Cretaceous rocks are not definitely known in the coast 
mountains of northwestern Oregon nor of Washington; yet 
certain beds are known along the Columbia River opposite 
Astoria, and in the Coast Ranges southward, that not im- 
probably belong to this period. In the vicinity of Puget 
Sound, in British Columbia, and on the adjacent islands, 
the Cretaceous rocks have a distribution not less important 
than they have in California. They rest here upon a base- 
ment of earlier Mesozoic and older rocks, and extend east- 
ward upon the flanks of the Cordilleran platform. As in 
Oregon and northern California, these beds are found 
occupying the chief valleys among a system of mountains 
composed essentially of pre-Cretaceous rocks. Farther 
north, on the southern coast of Alaska, Cretaceous beds 
are reported in the vicinity of Cook's Inlet, Kodiak Island, 
and on the Alaskan peninsula (Dall, 1895-96). They 
occur also at Rink Rapids, upon the Arctic border of the 

(2) October 23, 1902. 


The fossil remains found in most of the Cretaceous 
deposits throughout this vast stretch of continental border 
show them to be for the most part of marine, and of littoral, 
rather than of deep-sea origin. 

II. Historical Review. 

No other series of rocks upon the Pacific Coast has 
received so much attention as those of the Cretaceous 
period. It is perhaps due to their easy accessibility, and 
to the extremely interesting character of their fauna, that so 
many able contributions have been made to the literature of 
West Coast Cretaceous. Yet we are far from knowing all 
that is desirable concerning the stratigraphy and fauna of 
this interesting period. 

A brief review of the more important papers that have 
appeared from time to time, and accordingly a summary 
sketch of the development of our present knowledge of the 
subject, is here included for the benefit of readers who may 
not be familiar with what has already been done. 

The first announcement of Cretaceous deposits in Cali- 
fornia was by Dr. Trask (1856), in which he reported the 
discovery of ammonites and baculites in " Tertiary strata." 

Eight years later, in 1864, the first volume of the Paleon- 
tology of California appeared, in which Mr. Gabb pub- 
lished a large number of species from strata which he 
designated as Divisions yl. and ^. of the Cretaceous series. 
These are now known as distinct formations of Cretaceous 
and Tertiary age. Afterwards, in the second volume of the 
Paleontology of California, which appeared in 1869, Gabb 
distinguished four horizons of the Cretaceous, which he 
called respectively Shasta, Chico, Martinez and Tejon, the 
last two of which are now known to be Eocene, or only in 
part Cretaceous, as shown later. 

The beds exposed at Horsetown, and along the North 
Fork of the Cottonwood Creek, Shasta County, constituted 
what was termed the Shasta Group. It was stated that it 
contained fossils representing the ages from the Gault to 
the Neocomian, inclusive, of the European Cretaceous. 


The Chico Group was made to embrace all of the occur- 
rences of Cretaceous on the eastern side of the Sacramento 
Valley, some important beds in the vicinity of Mount Diablo 
and Martinez, in Southern Oregon, and the coal-bearing 
deposits of Vancouver Island. It was correlated with the 
Chalk of England, though not definitely with either division. 

The Martinez was believed to be distinct from the Chico, 
and was represented by beds at Mount Diablo, and near 
Martinez, Contra Costa County. 

In 1887, in connection with the work of the United 
States Geological Survey upon the quicksilver deposits 
of the Pacific Coast, Becker (1888) and White (1888 and 
1889) revised the classification of the California Cretaceous, 
recognizing essentially two divisions, the Lower and the 
Upper, separated by an unconformity. 

The Upper Cretaceous was called the Chico-Tejon, to 
which were annexed, as probably conformable with it, the 
Wallala Beds discovered by Becker on the coast of Sonoma 
and Mendocino counties, at San Diego, and in Lower 

The Lower, or Shasta Group, was made to include not 
only what is now recognized as properly belonging to that 
division, but they placed in it also a great series of meta- 
morphic rocks occurring in the Coast Ranges, as well as 
the Mariposa formation of the western Sierra Nevada, both 
of which are now known to be distinct from it. The lower 
portion of the Shasta Group was called the Knoxville, from 
its occurrence, with its typical fauna, at Knoxville in Napa 
County. The upper portion of the Shasta, or the Horse- 
town stage, was thought to be perhaps a portion of the 
same series, and involved with the Knoxville in the "pre- 
Wallala upheaval." 

It was afterwards shown by A. Hyatt (1894), J. S. Dil- 
ler (1894) ^"d J- P- Smith (1894) that the former view 
held by Professor Whitney regarding an unconformity 
between the Mariposa and Cretaceous strata was correct; 
that after the folding and metamorphism of the Mariposa 
slates the Cretaceous subsidence of the region had been 


inaugurated. An unconformity was also established by 
paleontological evidence, and the confusion that existed in 
regard to the various species of Aucella was finally settled. 

Paralleling in the Coast Ranges this separation of the 
Mariposa formation from the Cretaceous, the rocks that 
were thought to belong to the Shasta Group have been 
shown to consist of two unconformable series. It is due 
largely to the work of H. W. Fairbanks (1892, 1893, 1895, 
1896), Diller and Stanton (1894) and J. S. Diller(i893) that 
certain metamorphic and semi-metamorphic rocks of the 
Coast Ranges and the Klamath Mountains are recognized 
as lying unconformably below the Aticella-hQ^irmg shales, 
which have been called Knoxville. 

The Cretaceous series has been found to contain few, if 
any, rocks that have suffered a high degree of metamor- 
phism. The older complex is composed of both igneous 
and stratified rocks that may eventually prove to include 
members of Paleozoic, as well as of Mesozoic age, embrac- 
ing the Santa Lucia series of Willis (1900) and at least a 
portion of the Franciscan (Lawson, 1895), or Golden 
Gate (Fairbanks, 1895) series. The latter series was 
named from its important development in the vicinity of 
San Francisco Bay; it extends southward from the Klam- 
ath Mountains along- the coast of California, and in the 
Coast Ranges forms the basement of many later deposits. 
The Franciscan series is generally believed to be in part 
Cretaceous ; but much of it, including the Radiolarian 
cherts and some of the limestones and slates, is known to 
antedate the Cretaceous. 

In the paper by Diller and Stanton (1894), referred 
to above, it is shown that in the upper Sacramento Valley, 
on the flanks of the Klamath Mountains, beds that have 
been called Knoxville overlie unconformably an older 
metamorphic series, partly sedimentary, and partly igneous 
and cr3'stalline. The Cretaceous series was carefully 
studied in two more or less complete sections on the 
western side of the Sacramento Valley, ranging eastward 
from the Yallo Bally and Bally Choop mountains. The 


result has been a revision and reclassification of the Creta- 
ceous deposits, and the publication of some surprising facts 
connected with their occurrence and deposition. The 
astonishing thickness of these sediments in their deep- 
est section seems almost incredible, especiall}' when one 
considers the limited dimensions of their basin, and the enor- 
mous movements necessary for their formation and subse- 
quent folding. According to the estimates of these writers, 
about thirty thousand feet of sediments accumulated in the 
basin of the Sacramento without the intervention of any 
great disturbances, and during a period of continuous and 
prolonged subsidence. They have accordingly included 
in a continuous series all the strata of wKat is called the 
Shasta-Chico series, embracing the Chico, Horsetown, and 
Knoxville, and including rocks below the lowest Aitcella- 
bearing horizon. They recognize faunal changes in the 
series, but no decided breaks. 

Dr. T. W. Stanton (1895) published an extended list 
of Knoxville species, obtained from beds in the Shasta- 
Chico series below the upper limit of the range of the genus 
Aticella. More than fifty species are added by this con- 
tribution to the fauna previously known as belonging to this 
division. These species occur mainly in the upper portion 
of the Knoxville, within three thousand feet, stratigraph- 
ically, of what is believed to be the upper limit of the 
range of Aucelhi. 

From a more recent paper by the same author (Stanton, 
1897), it would appear that the Knoxville strata are to be 
correlated with the Comanche series of Hill, including the 
Trinity and Washita divisions. The Cretaceous series of 
California, south of Tehama County, has been less studied, 
but seems to be less simple than it is at the north. 

Fairbanks has reported in the neighborhood of San Luis 
Obispo a distinct unconformity between Atice/Za-hearing 
and Chico strata. 

It has also been shown by both Stanton (1895, 1895-96) 
and J. C. Merriam (1897) that the Martinez Group of Gabb 
consists of two parts, one indistinguishable from the Chico, 


and the other more nearly related to the Eocene. The 
upper division was designated the Martinez by Merriam. 
Between the typical Chico and the Martinez, as thus 
restricted, there is found to be neither a faunal nor a 
stratigraphic continuity, and the Martinez is provisionally 
classed with the Eocene. 

A similar series of Cretaceous deposits has been found in 
British Columbia and the adjacent islands by the geologists 
of the Canadian Geological Survey (Whiteaves, 1893). 
On Queen Charlotte Islands and the Island of Vancouver a 
succession of strata has been shown to range from the 
Lower Cretaceous or even Jurassic, upward to horizons 
equivalent to the Chico of California, There is not, how- 
ever, the apparent continuity in these beds that is claimed 
for the California series. But the fuller statement of their 
relations will be continued later. 

In central Mexico, near Catorce (Nikitin, 1890), fos- 
siliferous beds occur which have been referred to the 
Jurassic, but which Dr. Stanton thinks are probably to be 
correlated in part with the Knoxville of California (Stanton, 
1895, p. 26, etc.). The Aticellce and some of the ammon- 
ites are said to be very similar if not identical with Califor- 
nia species. 

Many important contributions to West Coast Cretaceous 
geology that are not here mentioned will be referred to 

III. Purpose of the Paper. 

The objects of the following discussion are primarily 
threefold. First, it is desirable to place in a more connected 
account the essential facts in regard to the Cretaceous 
deposits of the Pacific Coast, and particularly of California, 
with reference to their distribution, the physical conditions of 
their deposition, their disturbances, subsequent erosion, and 
other features of importance; and to add something as to the 
relations they bear to other formations with which they are 
territorially connected. Second, it is thought that a more 


complete classification of the series can be made, in which 
there shall appear its diversit}^ and complexity, as well as 
its unity. It is accordingly the aim to give here what are 
thought to be the most natural divisions of the series, which 
shall recognize both its physical and faunal changes in their 
more important phases, and call attention also to the devel- 
opment of its fauna in geological time. Third, it is possible 
to correlate with more precision than has yet been done the 
various members of the California section with those of 
neighboring basins, neighboring American provinces, and 
other countries bordering the Pacific, if not also with the 
Atlantic and Indian oceans. Furthermore, many new and 
interesting fossil forms occur in the Cretaceous of California 
and Oregon, and many types whose close affinities with east 
Asiatic and Atlantic species have not yet been sufficiently 

Probably no other formation is so favorable as the 
Cretaceous for the study of the distribution and historical 
development of the faunas embraced within its limits. The 
study of these problems may easily lead to the recognition 
of important changes that have taken place in the physical 
geography of North America and of the Pacific basin. In 
this connection it may be said that the limitations that are 
at present accepted for the different divisions of the Creta- 
ceous series of California may be subject to some important 
alterations, and that the closer discrimination of horizons 
is both desirable and possible. 

The physiography of California and Oregon, and perhaps 
of other West Coast regions during the Cretaceous, which 
ought to be connected with a study of this period, is not 
yet sufficient!}^ recognized, although of more than ordinary 
interest. Not only is the general shore-fine of the Creta- 
ceous ocean approximate!}^ known, but the principal inlets 
that indented the shore of that time may be clearly shown. 
Something also of the drainage and configuration of the 
surface may be inferred. 


IV. Stratigraphy of the Cretaceous. 
I. Basement Complex. 

In the foregoing review it was stated that the Cretaceous 
deposits of the West Coast are found, for the most part, 
occupying the present valleys, which are the results of a 
pre-Cretaceous folding, not yet obliterated. This fact is 
worthy of being further emphasized, since it is not yet suf- 
ficiently recognized. It can be shown in many ways that 
this distribution of the Cretaceous rocks is not to be attrib- 
uted to erosion, but it represents the original conditions of 
Cretaceous and pre-Cretaceous physiography. 

It has already been shown by Diller and Stanton (1894), 
by J. P. Smith (1894), ^"^ others, that the unconformity 
between the Knoxville beds and those of the older Mesozoic 
and pre-Mesozoic ages represents an uplift and period of 
land erosion prior to the Cretaceous deposition. 

Dr. Smith places this period of folding, metamorphism, 
and erosion at the close of the Mariposa epoch, or in late 
Jurassic time. Indeed, it is now the opinion of most geol- 
ogists that the prime movement (perhaps the intrusion) of 
the granitic core of the Sierra Nevada occurred at this 
period and was unquestionably the principal agent of both 
the folding and metamorphism of the pre-Cretaceous sedi- 
mentary rocks. Undoubtedly the diversification of the 
surface was considerable before the inauguration of the 
Cretaceous period, notwithstanding the subaerial reduction 
during the long land interval following the Mariposa epoch. 

It is interesting to remember in this connection the two 
parallel granitic axes of the Pacific border, most noticeable 
in the central portion of California, between which most of 
the Cretaceous and later deposits lie. It might be better to 
refer them only to borders of the Great Valley region of 
CaHfornia, were it not for the suggestiveness of well known 
facts outside of this latitude. 

Nearly parallel to the granitic core of the Sierra Nevada, 
a similar granite massif follows the coast from Santa 


Barbara County northward toward Sonoma. It is involved 
in a number of lesser ranges along the coast, among which 
are the Santa Lucia, Santa Cruz, and Montara ranges, and 
others on the coast north of San Francisco. The age of 
these granites is a matter of uncertainty, and it is conjec- 
tural to suppose that their movements have been contempo- 
raneous with those of the Sierra Nevada; but this is 
immaterial so far as the Cretaceous deposits are concerned, 
which, as has been said, occupy a position for the most 
part intermediate between the two, and only occasionally 
touch the granites of either mass. 

The components of the basement series upon which they 
rest are of various ages, and have roughly a concentric 
arrangement with reference to the Great Valley, forming a 
succession, inward, of Paleozoic and earlier Mesozoic 
rocks. The latest of these whose age is definitely known 
are the Mariposa slates of the Sierra foot-hills. In the 
Coast Ranges the unconformity of the Knoxville strata upon 
those of the Franciscan series, as at Mount Diablo, Santa 
Margarita, and other places, makes it apparent that this 
formation, which is probably also of Mesozoic age, forms 
a part of the basement of the Shasta-Chico series. Beyond 
the Mariposa slates on the east are the still older rocks of 
the Calaveras formation, while in the Coast Ranges, between 
the strata of the Franciscan series and the coastal granites, 
is found a series of ancient crystalline marbles and quartz- 
ites that can hardly be thought younger than the Paleozoic. 
Concentrically with these, tnough often overlapping them, 
are the later Mesozoic rocks of the Cretaceous, ranged 
along the borders of the Great Valley. 

Northward, in the Klamath Mountains, the underlying 
rocks range down in age even to the Devonian and older. 
Near Yreka, in Siskiyou County, Cretaceous deposits are 
found resting upon a series of micaceous and quartz-schists 
of either Devonian or earlier age. Throughout the region 
these schists are mantled over by a series of slates, gener- 
ally either silicious or calcareous, that remind one strongly 


of the slates and jaspers of the Franciscan series. The 
true relations of these slates to the Devonian rocks in the 
vicinity of Gazelle, in the same county, are not definitely 
known, though probably they include the strata of the 
Scott River Valley, referred to by Diller and Schuchert 
(1894) as probably Triassic. 

In Southern Oregon the basement rocks are largely simi- 
lar. Occasionally granitic rocks form the floor for Creta- 
ceous sediments, as at Ashland, Oregon, in the vicinity of 
Horsetown, and on some of the tributaries of the Cotton- 
wood Creek, Shasta County, and a stream of the same 
name in Siskiyou County, — California. But generally 
upon either margin of the Cretaceous basin there are found 
the folded and eroded older sediments. Thus both the 
situation and the distribution of the Cretaceous deposits 
are suggestive as to their period of folding; but the 
evidence is far from resting here. There are facts of 
erosion in the Klamath Mountains that furnish confirmatory 

2. The Sacramento Valley. 

The Shasta-Chico series, as represented in the upper 
Sacramento Valley, where it has been described by Diller, 
and afterward by Diller and Stanton, is said to consist of 
about thirty thousand feet of strata in which the sediments 
vary from conglomerates to sandstones and clay shales. 
The lower nineteen thousand nine hundred feet of the 
section along Elder Creek, Tehama County, is composed 
chiefly of shales with a subordinate amount of sandstone 
and of conglomerates, often of only local occurrence. 
Higher in the section, sandstones become more abundant, 
until at twenty-six thousand feet they give place to massive 
conglomerates and sandstones. The whole series has a 
varying dip to the eastward or southeastward, being near 
the base often nearly vertical, but generally not exceeding 
an inclination of thirty degrees. Toward the top it is 
sometimes but little disturbed. 


The fossiliferous portion of this series has been divided 
into three divisions, mainly upon faunal characteristics. 
The lower nineteen thousand nine hundred feet contain an 
abundance oiAucellce, of not more than two or three species, 
several species of Cephalopoda and other mollusks, also 
plant remains. This is the portion of the Cretaceous series 
to which the name Knoxville has been appHed. 

Stanton placed the upper Hmit of the Knoxville at the 
upper limit of the range oi Aiicella. Mr. Diller (1893, p. 
211) at one time stated that in the lower nineteen thousand 
nine hundred feet of the Elder Creek section the only fossil 
found was Aucella; and in another paper Stanton says that 
they are often so abundant in the strata that it would seem 
they must have monopolized the bottom of the sea. Later, 
however, Stanton (1895, pp. 11-85) pubHshed a large 
number of species as belonging to the Knoxville, many of 
which have come from the strata of this section or near it. 
But it is to be noted that the entire list of molluscan and 
cephalopod species added to the fauna of the Knoxville 
from this section has been found almost if not entirely within 
three thousand feet of the upper limit of the Knoxville, or 
in other words, within this distance stratigraphically of the 
upper limit of the range of Aucella. 

With the appearance of this new fauna at the top of the 
Knoxville, as then defined, the number of AucellcB gradually 
diminishes. This fact will be referred to further on. 

Above the upper limit of Aucella the shales continue 
uninterrupted, though becoming more sandy, for about six 
thousand feet, when they give place to conglomerates. It 
is the sandy and conglomeratic portion, confined to the 
uppermost four thousand feet of the series, that has been 
referred to the Chico division; while between this horizon 
and the Knoxville are the Horsetown strata. 

The section along Cottonwood Creek, Shasta County, 
some fifteen or twenty miles north of Elder Creek, corre- 
sponds closely with that already described in so far as the 
series is represented. On the Cold Fork of the Cottonwood 


it consists of the Knoxville with the overlying Horsetown 
and Chico strata; while on the North Fork the base of 
the Horsetown rests directly upon the older metamorphic 
and granitic rocks. 

Along the eastern side of the Sacramento Valley, in the 
foot-hills of the Sierra Nevada, only the upper portion of 
the series has been found, resting upon the metamorphic 
rocks of the "Gold Belt." Here the horizon, which 
perhaps should be considered as most typical Chico, is to 
be seen, though Gabb evidently included under that name 
more than is there represented. Diller states that the beds 
along the eastern side of the valley are much less disturbed 
than those on the west, being often nearly horizontal. The 
entire Cretaceous series, as has been shown by former 
writers, forms in the northern half of the Great Valley a 
geosyncline, which in its central portion passes below and 
is hidden by the accumulation of Tertiary and later strata, 
but which reaches the surface along both borders of the 
valley in the foot-hills of the Coast Ranges and Sierra 

In the papers already cited, Mr. Diller has shown that 
the Cretaceous series of the West Coast, as is illustrated by 
the deposits of the Sacramento Valley, was laid down 
under conditions of prolonged subsidence. A continuous 
though unequal settling of the sea-bottom from first to last 
is apparently demonstrated not only by the continuous and 
unbroken order of the series above described, all of which 
seems to indicate shallow water, but also by the successive 
overlapping and transgression outward of the younger por- 
tions of the series upon the border of older rocks that 
circumscribed the Cretaceous waters at each -epoch. The 
differential action of this movement in the coast regions 
cannot be better stated than in Mr. Diller's words (Diller and 
Stanton, 1894, p. 456). He says : "The large extent of this 
subsidence, from Alaska on the north to Lower California 
on the south, makes it an epeirogenic movement. There is 
evidence, however, that the movement, although epeirogenic, 


was not uniform throughout the whole area. * * * 
and it appears that the subsidence was greater in the 
Sacramento Valley than in the region of the Coast Range 
and Sierra Nevada." And continuing the same topic he 
adds: "If the subsidence was uniform throughout the 
whole region it follows that what is now the western foot of 
the Sierra Nevada, as well as the corresponding portion 
of the Coast Range, where in both cases the Chico rests 
directly upon the folded pre-Cretaceous rocks, must have 
been at an elevation of twenty-five thousand feet above the 
sea when the basal portion of the Knoxville was deposited 
in the Sacramento Valley. This hardly seems possible, for 
we know of no such mountains in the country to-day. It 
seems much more probable that the subsidence was not 

It is probable that at no time during the subsidence was 
the whole of either the Sierra Nevada or Klamath Mount- 
ains below the sea. Scattered areas of Cretaceous deposits 
occur among the Klamath Mountains west of the Sacra- 
mento Valley; but it is not necessary to suppose that the 
sea reached these localities across mountain summits. 
More likely it found its way into earlier basins through inlets 
from the open ocean at the west. This was undoubtedly 
the case in Southern Oregon, where portions of the same 
series are represented in different places. 

3. The Oregon Basin. 

In Rogue River Valley, beds of Upper Cretaceous age 
occur, following generally the western side of the valley, 
and resting tipon the older metamorphic slates and crystal- 
line rocks, with a fairly uniform dip toward the east. The 
strata consist for the most part of sandstones and conglom- 
erates, with a subordinate amount of shales. The con- 
glomerates predominate in the upper part of the section, 
while shales are common at and near the bottom. These 
beds are apparently equivalent to those of the Upper 


Cretaceous of the Sacramento Valley, to which they will be 
compared in more detail in another section. Similar beds 
are found in northern California. 

In Douglas County, near Riddles, is a syncline of Creta- 
ceous strata folded between areas of older metamorphic and 
intrusive rocks. Lithologically it is a repetition of the 
equivalent portion of the Shasta-Chico series at the south, 
consisting of shales, sandstones, and conglomerates. The 
conglomerates are said by G. F. Becker (1891), who first 
described the section, to predominate in the upper part of 
the series, and to be very extensive. Only the middle por- 
tion of the Sacramento section is represented in these beds, 
which are in part Knoxville and in part belong to the 
Horsetown. Chico strata have not been reported for this 
immediate locality, but they occur at some distance to the 
southeast on tributaries of Rogue River. 

These Oregon deposits, especially the lower strata, 
appear to belong to an embayment distinct from that of the 
Sacramento Valley; but they show a similar transgression 
of the later members of the series, only in this case the 
expansions were toward the southeast. 

4. British Columbia. 

Upon the mainland and islands of British Columbia the 
Cretaceous deposits form a series of considerable impor- 
tance, which, while not so connected as that of California, 
is almost as complete, and is, perhaps, entirely comparable 
to it. Aucella-hQ.'A.x'wi^ strata which perhaps form the bottom 
of the series are found both upon the mainland and upon 
the Queen Charlotte Islands. The following tabular view 
after Dawson (1889, P- ^27) represents the Cretaceous 
series of these islands, to which are annexed a few of 
the fossil species characteristic of each division. 





strata. Thickness. 


Important Species. 




Upper shales 
and sandstones 


Lower shales 
and sandstones 
(with coal ) 





Inoceramus labiatus. 

Belemnites sp. 

iLytoceras sacya, L. timotheum, 
1 Desmoceras breweri, 
D. dawsoni, and D. plattulatum. 
\Aucella, Perisphinctes, etc. 





.... Pleuroniya lavigata, Neniodon, 

The lower portion of "Division C" perhaps ought not to 
be included in this part of the section, and may eventually 
prove to be equivalent to the ^wce//«-bearing beds of 
Tatlahcoh Lake, and to represent also a horizon consider- 
ably below the upper portion of C . Farther south, upon 
the northern end of Vancouver Island, in the vicinity of 
Quatsino Sound, the three upper members of this series 
are found. Here also Aucella and other species are 
reported which appear to belong to the Knoxville. 

At the southern end of Vancouver's Island, near Comox 
and Nanaimo, strata occur that have been correlated with 
the Chico of California ; they consist of shales and conglom- 
erates, amounting in thickness to about five thousand feet. 
These deposits contain the coal-bearing beds of Vancouver's 
and the neighboring islands. Still further southward, on 
the borders of Puget Sound, is the coal-bearing Puget 
Group of White (1889), which has been compared to the 
Laramie, a series that is thought to be of Tertiary age, or 
at least later than the Chico. 

The relative position of these deposits, all of which rest 
directly upon earlier Mesozoic or older rocks, suggests a 
Cretaceous basin extending southward, in which there was 
a continued subsidence and transgression of the sea similar 


to that already described for Oregon and California. This 
was the view held by Dawson (1890) prior to the recogni- 
tion of the fact in Californian deposits. Similarly the 
Cretaceous deposits upon the mainland of British Columbia 
are said to occupy basins in older metamorphic rock. 

South of Puget Sound massive beds of conglomerate 
occur along the Columbia River, which may belong with 
those of the upper portion of the Nanaimo Group. They 
contain few fossils ; yet such as they are they may well be 
taken to support this view. 

yl?^d:^//«-b earing deposits are reported from different 
points along the Alaskan coast (Dall, 1895-96), as at Cook's 
Inlet, Kodiak Island, the Alaskan peninsula, etc. Whether 
they belong to the Cretaceous or Jurassic age has not been 
settled; yet undoubtedly some of the species are of Creta- 
ceous type. Chico deposits are now known to occur near 
the mouth of the Yukon River, Alaska. Much of the 
rock is a shale, either clay or calcareous, but limestones, 
sandstones, and even conglomerates occur with Mesozoic 
fossils. ylwc^//rt-b earing rocks are also reported from 
Porcupine, Lewis, and Yukon rivers. 

5. Southern Occurrences. 

Southward from California there are but few deposits 
known that can be classed as belonging to the Pacific 
province, which will be mentioned here. 

Near Catorce, in the state of San Luis Potosi, Mexico, 
an Attce//a-hed.rmg formation has been described (Felix 
and Lenk, 1890), which Dr. Stanton (1895, pp. 25-27) 
thinks is equivalent in part to the Knoxville. Also in 
southern Mexico are beds that have been referred to the 
Lower Cretaceous, and are thought to represent a portion 
of the Knoxville ; but too little is known of these deposits 
for exact correlation. 

Upon the island of Quiriquina, off the west coast of Chili, 
Upper Cretaceous deposits occur resting upon schists of un- 
certain age, and in turn overlaid by Tertiary beds. The 
Cretaceous deposits consist of calcareous and glauconitic 


sandstone, with basal conglomerates, all of marine origin, 
and containing several fossil species common in the Upper 
Cretaceous of California. Besides the molluscan remains, 
these deposits contain several species of saurians and certain 
plants, some of which have been described by Steinmann 
(1895) and his associates. 

6. Correlation. 

But little can be done at correlating these widely separated 
deposits upon purely stratigraphical resemblances. In no 
one section is there a series that can find its exact parallel 
in any other, much less in all the others. It is to be 
noticed throughout, however, that the cycle of sedimentation 
in these deposits is the reverse of the normal order. Shales 
invariably are more abundant in the lower part of the sec- 
tions, sandstones increase as one ascends the series, and 
conglomerates are more common in the upper portions. 
This is sometimes so, even where there is only a part of the 
entire series present, as in the vicinity of Medford and 
Ashland, in Rogue River Valley, Oregon. Yet this is not 
always so; at Horsetown and at Ono, Shasta County, the 
local base of the Cretaceous contains heavy beds of con- 
glomerate. But little reliance can be placed in these con- 
glomerates, however; for as Diller has stated, they are 
often of only local extent, and may merely show the position 
of some stream in mid-Cretaceous time. Their irregularity 
nevertheless affords some interesting suggestions. 

The regional subsidence and the deposition of these beds 
could not have been quite so continuous as has been imag- 
ined, thouofh the disturbances have been more or less local; 
still, there are some broad uniformities- noticeable in the 
widely distributed deposits. Tawny or grayish sandstones 
and pebbly conglomerates characterize the Chico and Upper 
Horsetown ; while dark or yellowish clay shales are more 
common in the Knoxville portion of the series. If the 

(3) October 28, 1902. 


heavy beds of conglomerate in the vicinity of Riddles, 
Oregon, really belong, as Becker believed, at the top of 
the section, their apparent extensiveness would justify their 
being compared to the conglomerates of "Division i?" of 
the Queen Charlotte Islands section ; and they might also 
find their equivalents in the sections of California. 

V. Faunal Changes of the Cretaceous. 

I. Recognized Diversity. 

The work of Diller and Stanton has demonstrated how 
little was previously known concerning the Cretaceous 
series of California. From their study of the Cretaceous 
deposits in the Sacramento Valley, they have felt compelled 
to abandon the views of earlier writers regarding the com- 
plexity of the series; while on the other hand, they have 
emphasized the evidence of unbroken stratigraphic succes- 
sion from bottom to top. Less effort has been made to 
represent its actual diversification, either physical or faunal, 
whatever this may be; and accordingly it remains to be 
seen how far from simple were the conditions of deposition 
in the Pacific border province during Cretaceous time ; yet 
it appears that sufficient has been known for arriving safely 
at conclusions somewhat different from those reached in 
the accepted summary of our knowledge. 

It is entirely natural that the historical development of 
the subject should be as it has been. Early collectors 
working less thoroughly over the scattered deposits have 
noticed the more striking dissimilarities without being able 
to recognize connecting elements that a more detailed 
study has discovered. Attention has been called to the 
physical peculiarities of the Sacramento section of the Cre- 
taceous, which shows on the whole a cycle of sedimenta- 
tion somewhat the reverse of the normal. There is a certain 
evidence in this fact that leads one to suspect that the 


series as a whole is not altogether simple, and that in the 
closing epochs disturbances were both more numerous and 
more general. Similarly, when the series is made the sub- 
ject of faunal study, a diversity that is still more significant 
is soon recognized. The faunal differences that are ordi- 
narily seen have led to the distinctions hitherto made, and 
to the divisions of the series settled upon by the earlier 
writers; but these differences are real and not merely 
apparent. It is evident to one coming from the fossiliferous 
beds upon the eastern border of the valley, where gastro- 
pods and bivalves largely predominate, to the beds of the 
Cottonwood, where cephalopods are so common, that one 
has reached an entirely different faunal horizon. So, also, 
when one proceeds to the more basal portions of the series 
in the foot-hills of the Coast Ranges, one finds again a 
complete faunal change. The cephalopods of the last hori- 
zon gave place to a fauna composed almost entirely of one 
or two species of Aiicella. These facts led to the recogni- 
tion of the three horizons commonly known as the Chico, 
Horsetown, and Knoxville, which, in spite of the connect- 
ing elements uniting them, have not yet been, and ought 
not to be, abandoned. Indeed, it is not improbable that 
upon further study additional reasons will be found for still 
further enforcing the distinctions, and even, as it now 
appears, of subdividing some of the principal divisions that 
are at present accepted as paleontological units. 

Both Diller and Stanton have been convinced of the 
transitional character of the fauna from one level to another 
in different parts of the series. New forms appear succes- 
sively and continue for unequal periods and disappear at 
different stages of the overlying series. Some forms are 
of short duration and some are very much more persistent. 
Many lists of species taken from different localities and 
representing different horizons have been published, which 
apparently show this; and undoubtedly within certain limits 
there is a more or less gradual change, and for some pur- 
poses these facts may well deserve attention. Yet the 


changes in the total faunas, as well as they can be known 
from the fragmentary collections that have been made and 
studied, do not seem to warrant the assertion of a uniformly 
transitional series, and perhaps this has not been claimed 
Yet the breaks that had previously been conceived to exist 
between the main divisions of the series were bridged over 
or minimized by the passage across them of many impor- 
tant forms. Thus it was left to be inferred that the transi- 
tion from the Horsetown to the Lower Chico might not be 
different from that between different parts of the Horse- 
town itself, except perhaps locally. But our knowledge of 
the fauna as a whole, of each of the different horizons 
above named, has gradually become more complete by the 
continual contributions that have from time to time been 
made; and while it can not be called quite satisfactory, yet 
on the whole it may be regarded as sufficient for at least 
some general observations. It must be borne in mind, 
however, that the Cretaceous species of California need a 
revision before any final conclusions can be established or 
an entirely reliable correlation made, based upon paleonto- 
logical evidence. Much confusion has undoubtedly existed 
in regard to the limits and range of certain species, that has 
often resulted from laxness in the identification of species. 
In the subjoined portion of this paper attention is called 
to a few of the many corrections that are needed for a 
more satisfactory treatment of the subject, and which a 
successful treatment will demand. However, for the pres- 
ent there are some general facts that may be clearly 

2. Horizons Distinguished. 

The Chico Efoch. 

Regarding each division of the Cretaceous separately, 
the fossil lists contributed by a number of its recognized 
localities may be massed together, and by this means a 
more complete idea of its general fauna can be gained than 


if but a few of its localities are taken independently. It is 
found in this way that there are recognizable elements 
apparent in each fauna, which may be safely depended 
upon, and that while there is more or less of a transitional 
character in the fauna of a given level, yet it does not 
depart from the main type to any considerable extent until 
the time arrives for an almost complete change. The 
Horsetown fauna, for example, consists of a large number 
of cephalopod forms, which is as great if not greater than 
the whole number of other mollusks combined. This can 
not be claimed for the Chico upon the eastern side of the 
valley, where the whole number of cephalopods known is 
not greater than one-eighth of the number of other mol- 
lusks, and even in the strata immediately overlying the 
Horsetown upon the west, which have been hitherto re- 
ferred to the Chico, the proportion of cephalopods known 
is not more than one-third that of the others. The rapid 
increase in the number of gastropod and bivalve species 
in the Chico is, however, the noteworthy fact; while at the 
same time, the number of cephalopods as rapidly dimin- 
ishes, except, perhaps, in more favored localities. 

In the Great Valley basin of California the transition of 
faunas is more gradual than it has been in any other basin 
of the Pacific border; and for that reason the faunas repre- 
sentative of the different horizons are not so easily distin- 
guished. For purposes of correlation, therefore, it is safer 
to select for study, if possible, localities lying outside of the 
boundaries of the Great Valley, in which these distinctions 
can be more readily made. And for the Chico epoch this 
is both possible and especially desirable. The faunas of 
the Chico are therefore represented in the following lists, 
massed from a number of the more significant localities, as 
will be shown later. Each division of the Chico, the Upper 
and the Lower, is represented by four^ such localities, 
the lists being for the most part compiled, in a somewhat 
revised form, from others already published. For the 
Upper Chico the localities selected are in the Sacramento 


Valley, and have been well described by Gabb, White, and 
others; while for the older division of the same epoch the 
localities are mostly new or have not yet become perfectly 
known. It seems to be especially important that the Lower 
Chico should be studied in such a manner. 

Of the Lower Chico localities selected for study, two lie 
to the north and two to the south of the Great Valley basin, 
and are as follows: {a) near Phoenix, Jackson County, Or- 
egon; (<5) Henlev, Siskiyou County, California; (c) Silver- 
ado Canyon (Bowers, 1890), Orange County, California; 
(<^/) near San Diego, San Diego County, California, including 
localities at Point Loma and La Jolla. 

Locality (c), Silverado Canyon, is intended to represent 
the Lower Chico beds of the Santa Ana Mountains, 
Orange County. The fauna of this horizon has recently 
been reinforced by collections sent to the State University 
by Dr. Stephen Bowers of Los Angeles. Some of the 
localities from which his collections were made are very 
near the Silverado Canyon, and hence are included with it. 
Bowers' Canyon is thirty miles northwest of Los Angeles, 
and from the fossils furnished by this locality it belongs to 
the same horizon. 

Species occur in the following lists that are referred 
to locality (c) by use of the letter '* R," as explained 
in the foot-note. 


List of Fossil Species from Chico Localities.^ 





w - 




s 1 

ft ' 







Acanthoceras cotnpressmn, sp. nov | 


Acatithoceras navicular e ^L\NT 


Acanthoceras rotoniagense Stol 


Anrvlnrpra's lineatutn Gabb 


Ancyloceras ( ? ) quadratum Gabb 


Finrulifp'i rhicopn'iis Trask =t 



Baculites fairbanksi, sp. nov 



fiarulitp'i sn 



Desnioceras ashlandicum, sp. nov 



Desmoceras hoffmanni Gabb 




Desnioceras siigatum Forbes 





Hamites armatus, sp. nov 


Hamites cylindraceus De France 




Hamites ellipticus, sp. nov 


Hamites phcenixensis, sp. nov 


Hamites vancouverensis 


J-fp]inrpv(i'\ lireweri Gabb 

Helioceras declive Gabb 


1-fp]inrpvn ^ ^n 

Heteroceras cooperi Gabb 


Heteroceras r^\^ H. reussianum d'Orb... 


f-fnhJitpK yp77tOfttii Garr. 


/ vfnrprn'i hafp'si Garb 


Lytoceras jacksonense, sp. nov 



T vtnrpvn^ iukp'si f ■'1 Sharpe 


r vfnrprn'i larva Forbes 




Mortoniceras crefiulatuin, sp. nov 


Nautilus danicus ( ? ) Schloth 




Mniitilii^ sn 



Pachydiscus newberryanus Meek 



Pftrhvdi^rw! sd 

Phvllnrprn'i ra)HOSUin Meek 


Placenticeras cali/ornicum, sp. nov 





1 In the following lists, K = reported, S = substituted from neighboring and equiva- 
lent deposits, ? = identity doubtful. 


[PROC. 3D Ser. 





n n 

50 ►« 






Pl/yr/'iifir/'vnt: -hn ri /iruin Smith 




J^irin^jnf'i^nhi ^ hi^fl'il'ilPVI mi flOV 


Ptychoceras sp 



'\rnhhHt"\ rnndoni sn nov 


'srn'hhUpK cilliKi sn nov 


'\rnhhifp'\ inertni'! sn nov 


'\rnhhitp<i klninn{hpn'\i% sn nov 


Scai)hites ■bewini SD. nov 


^rnhhitp^ vcip'upn'si's. sn nov 


Srhl(Enbachia bakeri SD. nov 


Schloenbachia blanfordiana ( ? ) Stol 


'srhlrpnhnrhia. hufffn'ii'; sn nov 


Schloenbachia chicoensis Trask 




Schlcenbachia (rcibbi. sd. nov 


Schlcenbachia knie'hteni, sd. nov 



Schlcenbachia miilticosla, sp. nov 


Schloenbachia oregonejtsis, sp. nov 




SrlihrnheirhicL ■hvot>inaucL Stol 


Schloenb'chia siskiyoueiisis, sp. nov 



Schloenbachia sp. undt 


Schlcetibachia sp. undt 


Aciceon inornatus Gabb 


ArffT'on ifup'ili'; Stol 


Actcconella oviforniis Gabb 


AftcEonina califoynica Gabb 

Aclceonina pupoidcs Gabb 



Actfxonina sp 


Actceonina sp 

AinauYopsis alveata Gabb 


Aniauropsis ovi/omiis Gabb 

Anchura calif ornica Gabb 



Anchura condoniana^ sp. nov 

Anchnra falciforniis Gabb 

Ancillaria elongala Gabb 


Angaria ornatissima Gabb 







Architedonica mornata Gabb 
Architedonica veatdii Gabb . 

Bulla sp 

Calliostoma sp 

Calliostoina radiata Gabb 

Cerithiutn pilingi White 

Cheinnitzia sp 

Chentnitzia planulata Gabb . . . 

Cinulia obliqua Gabb , 

Cotninella lecontei White 

Cylic/iJia costata Gabb , 

Deiitaliuin cooperi Gabb 

Dentalimn siraniineuin Gabb, 

Discohelix leana Gabb 

Eniarginula radiata Gabb. . . , 

Erato veraghooretisis ( ? ) 

Eripachya ponderosa Gabb . . 
Faunus mariciduliis White. . 

Fulgur hilgardi White 

Fulguraria gabbi White 

Fhsus averilla Gabb 

Globiconcha renwndi Gabb. - . 
Gyrodes co7iradiana Gabb . . . . 

Gyrodes expansa Gabb 

Gyrodes pansa Stol 

Haliotis loniaensis, sp. nov.. . , 

Haydenia iuipressa Gabb 

Helcyun dichotoma Gabb. 

Littorina compada Gabb 

Lunatia pagoda Forbes 

Lysis duplicosta Gabb 

Lysis oppansa White 

Margaritella globosa Gabb . . . 

Mesalia obtusa Gabb 

Nerita cuneata Gabb 


(Kl 5 


n ^■ 
n n 

53 O 

" 2 

• 93 












Op a 

Patella traski Gabb 

Perissolax brevirostris Gabb j ^ 

Phasionella sp 

Potarnides tenuis Gabb 

Ringicula varia Gabb 

Scobinella dilleri White r 

Stomatia sucicensis White 

Straparolliis lens Gabb 

Straparolbis paucivolvus Gabb 

Trito7iiuin sp 

Trochiis goni/erus White 

Trophon condoni White j 

Turritella chicoensis Gabb | » 

Turritella robiista Gabb « 

Turritella seriatini-granulata Gabb. . . . 

Turritella veatchi Gabb 

Vasculum obliquum White 

Anatina inequalateralis Gabb 

Anomia sp 

Anomia sp 

Asaphis undulata Gabb 

Astarte conradiana Gabb 

Astarte rnatthewsoni Gabb 

Astarte tuscana Gabb 

Avicula fiitida Forbes 

Avicula pellucida Gabb 

Cardiuin reniondianuin Gabb 

Chione varians Gabb 

Clisocolus dubius Gabb 

Coral liochama orcutti White 

Corbula cultriformis Gabb 

Corbula traski Gabb 

Crassatella loinana Cooper 

Ciicullcea bower siana Cooper 

Cticullcea decurtata Gabb 

■ . n 

" 2 

■ m 





















* * 











rr> n 











Cuctdlcea trjincata Gabb 













Cyprimeria lens Gabb . . 

Dosinia injiata Gabb 

Dosinia pertennis Gabb 

Dosinia sp 


Eriphyla nnibonata Gabb 






Exosryra parasitica Gabb 


Exozyra sp 

Exosyra sp 

Goniomya borealis Meek 

Gryphcsa vesicularis Lamark 


Inocerainus adunca, sp. nov 

Inoceramus labiatus Schloth 

Inoceramiis multiplicaius ( ? ) Stol 

Inoceramus Vancouver ensis Meek 

Inoceramus whitneyi Gabb 


Lima appressa Gabb 

Lima jnicrotis Gabb 

Lima shasf ensis Gabb 

Limopsis transversa 

Lithophagus oviformis Gabb 

Lticina postice-radiata Gabb 

Lucina subcircularis Gabb 

Lutraria truncata Gabb 

Mactra ashburneri Gabb 



Mactra gabbiana, sp. nov 

Martesia clausa Gabb 

Meekia navis Gabb 

Meekia radiata Gabb 

Rleekia sella Gabb 

Meretrix arata Gabb 

Meretrix longa Gabb 

Meretrix nitida Gabb 

* \ * 

Modiola cylindrica Gabb 

Modiola siskiyouensis Gabb 

Mytilus pauper cuius Gabb 





Mytiliis quadratus Gabb 

Nemodon vavcouver'ensis Mkek. . 

Niicula solilaria Gabb 

Nucula trnncata Gabb 

Ostrea sp 

Patiopaa concentrica Gabb 

Pecten appressa 

Pecten californica Gabb 

Pecten operculiformis Gabb 

Pecten traski Gabb 

Pectnnculus pacificus, sp. nov. . . . 

Pectiinculus veatchi Gabb 

Pholadontya breweri Gabb 

P/ioIadoinya anadna, sp. nov 

Pinna breweri Gabb 

Placosniilia sp 

Pleuromya Icevigata Whiteaves. 
Protocardium placerensis Gabb . 
Protocardimn scitiduin Meek... 

Tellina ashburneri Gabb 

Tellina decurtata Gabb 

Tellina hoffnianni Gabb 

Tellina monilifera Gabb 

Tellina o'dides Gabb 

Tellina paralis Gabb 

Terebratella sp 

Terebratella obesa Gabb 

Thetis annulata Gabb 

Trigonia evansaTUi Meek 

Trigonia rel. T. evatisafia 

Trigonia leana Gabb 

Trigonia tryotiiana Gabb 

Trapezium carhiatuni 

Venus veatchi 






Waldheimia inibricata Cooper. 






rt B 





Summary of Facts Appearing in the Lists. 


Number of Species 

common to 

Upper and Lower Chico. 

Number of 
Species common 

to the Chico, 
North and South. 

to the 

to the 


Cephalopods . 

4— (2 doubtful). 

12 species. 




Gastropods . . 

I Some donbtful 
1 determinations. 

^ Hardy forms 

16 species. 





17 < or not 
( characteristic. 

19 species. 





32 species. 

47 species. 




An examination of the preceding tabulated lists makes it 
apparent that there are two distinct horizons in the Chico 
of California and Oregon, each having a fauna to a consid- 
erable extent peculiar to itself. A summary of the facts to 
be gathered from this list is presented. It will be observed 
also that the species belonging to the two divisions are 
supplementary rather than similar. In the Lower Chico 
there is shown a large number of cephalopods, several of 
which are common to both the northern and southern 
localities; only two of them, however, are certainly com- 
mon to the upper and lower divisions. Similar facts will 
be noticed for the other classes. Also, as will be seen 
later, very few of the Chico forms are those of the Horse- 
town portion of West Coast Cretaceous. Some of the 
forms more characteristic for criteria of correlation are 
those of the following lists: — 

Characteristic Forms of the Chico. 
Lower Chico Forms. Upper Chico Forms. 

Acanthoceras sp. 
Desmoceras hoffnianni 
Desnioceras sugatum 
Desmoceras ashlandicurn 

Baculites chico'ensis 
Ancyloceras lineatum 
Helicoceras breweri 
Helicoceras declive 



Upper Chico Forms. 

Pachydiscus 7iewberryanus 
Schloenbachia chico'insis 
Schlcenbachia gahbi 
Aiichura fakifonnis 
Eripachya pofiderosa 
Fulgur hilgardi 
Fiilguraria gabbi 
Gyrodes expansa 
Perissolax brevirostris 
Tnrritella chicoensis 
Turritella robusta 
Tellina sp. 
Meekia sp. 
Anoviia sp. 
Lntraria iritncata 
Lucina sp. 
Trigonia evansana 
Pecfuncuhis veatchi 
Venus veatchi 

Lower Chico Forms. 

Lytoceras sacya 
Ly toe eras j acksonense 
Lytoceras jukesi 
Placenticeras pacifictiin 
Placenticeras caltforn icu m 
Phylloceras rarnosum 
Nautilus sp. 
Prionotropis sp. 
Scaphites sp. 

Schl(£7ibachia oregonensis 
Schlcenbachia in nit i cost a 
Schloenbachia propinqua 
Schloenbachia siskiyouensis 
ActcEon pugilis 
Actcsonella oviformis 
Actceonina californica 
ActcBonina pupoides 
Antanropsis alveata 
Anchura californica 
Anchura condoniana 
Inoceramus labiatus 
Inocerainus xvhitneyi 
Lima appressa 
Lima microtis 
Nemodon vancotiverense 
Pecten operculiformis 
Pinna breweri 
Pleuromya Icsvigata 
Protocardium scitulnni 
Trigonia rel. T. evansana 
Trigonia leana 
Thetis aimnlata 

Considering, then, the Lower and the Upper Chico, it 
will be seen not only that there is a quite noticeable devel- 
opment of gastropod and bivalve species in passing from 
Lower to Upper, but there is also a large omission of former 
species and genera and their replacement by others of 
usually different groups. For example, of the many species 
of cephalopods found in the Lower division, only four have 
been thus far reported from the Upper; and only two with 
certainty of identification. Among the gastropods only 
eleven have been reported as common to the two horizons 
and some of them are likewise doubtful. Others, as Gyrodes 
expansa and Cinulia obltqua, are forms that might easily be 


mistaken, or at best are not characteristic. One or two 
species of Turrttella are found in the Lower Chico, and 
four in the Upper, only one of which is common to both. 

Among bivalves a greater number of forms is found, 
continuing from the earlier to the later deposits; but this is 
perhaps to be expected, partly from their more simple habits, 
and partly from their greater numbers. But with these also 
a critical examination will result in lessening their apparent 
importance. Not more than twenty species are shown to 
have survived from the earlier to the later Chico, and among 
them are Chione varians, Uomomya concentrica, Exogyra 
parasitica, Afeekia sella, and perhaps Inoceramus whitneyi, 
none of which are of very decisive character. Of the 
others, Pecttinculus veatchi, CucuUcea triincata, and T^i- 
gonia evansana, while they are more distinctive forms, have 
each near allies in the Cretaceous of the West Coast, among 
which there has not yet been a close discrimination. Tti- 
gonia dawsoni, from the Queen Charlotte Islands, is related 
to Trioronia evansana of the Comox beds. There are at 
least two varieties of Pectunciilus veatchi, besides a new and 
nearly related species, while Cncullcea truncata from the 
Chico resembles superficially a Trigonarca from the Queen 
Charlotte Islands. One needs to be reassured by careful 
comparisons before yielding to first impressions. Nuciila 
truncata, if not some of the others, has caused a similar 
confusion elsewhere by crossing a well established break 
from the Chico to the Tejon, and even into the Miocene, 
and ought not to be regarded seriously here. 

But the distinction between Upper and Lower Chico 
does not appear to need this sort of defense. It could be 
properly made even if a much larger number of species 
was found to have crossed the interval. It may be true 
that a larger number will be found when the localities are 
more carefully searched; but even so, future explorations 
will probably also increase proportionally the number that 
have not crossed the line ; so that it is safe to say the ratio 
of species that have survived from the earlier epoch will 
not be materially increased. 


If the faunal dissimilarity that is apparent in the Lower 
and Upper Chico is to be taken as evidence of a disconti- 
nuity in the deposition of this member, it ought also to 
appear in deposits outside of the basin of the Sacramento, if 
the disturbance extended so far. And when the lists of 
Chico species from the different localities are examined 
with a view to discovering such evidence, it can only be 
said that the fragmentary collections that have been made 
at distant points thoughout the Coast Ranges toward the 
south are, as a rule, either prevailingly Upper or prevail- 
ingly Lower Chico for any given locality. The various 
papers by H. W. Fairbanks furnish a number of such lists 
that will be found interesting. 

Upon the Eagle Ranch in northern San Luis Obispo 
County, the Chico beds that immediately overlie the 
Aticella-\i^-Ar\x\^ shales have furnished the following spe- 
cies: Baculites chico'cnsis, Trigonia evansana {'^),Pectun- 
culus veatcht, CticullcBa sp., and Pentacrimts. None of 
these species belong exclusively to the Lower Chico, while 
some of them have never been found there. Baculites chi- 
co'cnsis is, perhaps, peculiar to the Upper division alone. 
The Pecluncidus and Pentacrinus are probably undescribed 
species. Farther southward, in Santa Barbara County, 
a collection from the Sisquoc Canyon consists of the 
following: — 

Inoceramus sp. Pectunculus veatchi 

Baculites chicoensis Meekia sella 

Dentaliuin stramineum Cinulia obliqua 

Cylichna costata Tellina ashburneri 

The same evidence appears in this list as in the preced- 
ing, except that more of the species are those of the Upper 
Chico alone. Such evidence is, of course, only corroborative, 
and does not of itself establish the fact of different epochs 
for the Lower and Upper Chico. It shows, however, that 
the subsidence that attended or introduced the later portion 
of the Chico was not entirely local. Other occurrences of 
the Chico are represented in the following lists. 



It is not claimed that the Upper and Lower divisions of 
the Chico are entirely distinct, but only that there is a 
sufficient difference between them to warrant their dis- 

In widely separated localities both portions of the Chico 
seem to be represented together, though perhaps with more 
careful study the deposits might be found separable. In 
the vicinity of the Bay of San Francisco, four localities 
may be mentioned which will be found interesting. The 
connections between them are not known, except that they 
are not distant from each other geographically. It will be 
noticed that in two of these lists, Martinez and Pacheco 
Pass, the species are prevailingly those of the Upper Chico, 
though at Martinez a species of Trigonia occurs which has 
been supposed peculiar to the Lower Chico. In the list 
from Curry's, south of Mount Diablo, the species of the 
Upper and Lower horizons appear to be about equally 
mingled. A little farther south, in the Livermore Valley, 
Alameda County, fossils occur that are certainly below the 
Upper Chico, if not below the Lower; but this will be dis- 
cussed later on. 

Pacheco Pass. 

Baculjtes chico'ensis Trask 
Gyrodes conradiana Gabb 
Lhna appressa Gabb 
Lutraria truncata Gabb 

Meekia sella Gabb 
Perissolax brevirostris Gabb 
Pharella alta Gabb 
Tellina matthewsoni Gabb 


ActcBoniyia californica Gabb 
Chione varians Gabb 
Cucullcea truncata Gabb 
Desmoceras jugalis Gabb 
Eriphyla tunbo?iata Gabb 
Fulgiiraria gabbi White 
Globiconcha rei)iondi Gabb 
Inoceranius whitneyi Gabb 
Lytoceras batesi Trask 
Mactra ashburneri Gabb 


Margaritella globosa Gabb 

Meekia sella Gabb 

PachydiscHS newberryantis Meek 

{Ammonites fraternus Gabb) 
Pectuncidus veatchi Gabb 
Pharella alta Gabb 
Trigonia evansana Meek 
Trigonia leana Gabb 
Turrit ella sp. 

November 12, 1902. 



South of Mount Diablo. 

Acanthoceras tiirtieri White 
A7ichiira californica Gabb 
Baculites chicoensis Trask 
Chio7te varians Gabb 
Cucullcea trimcata Garb 
Dentalium cooperi Gabb 
De?italiuin straniineutn Gabb 
Eriphyla timbonata Gabb 
Lilt r aria alveata Gabb 
Lytoceras baiesi Trask 
Mactra tenuisshna Gabb 
Meretrix nitida Gabr 
Nautilus sp. 

Pachydiscus suciaensis Meek 
Pec ten operculiforntis Gabb 
Pijuia breweri Gabb 
Schlutheria diabloetisis, sp. nov. 
Scobinella dilleri White 
Trigonia cequicostata Gabb 
Trigonia evansana Meek 

Southwest of Martinez. 

Chi one varians Gabb 
Cifiulia obliqua Gabb 
Corbula cultriforntis Gabb 
Cylindrites brevis Gabb 
Dentalium cooperi Gabb 
Gyrodes expansa Gabb 
Gyrodes conradiana Gabb 
? Helicoceras verviictdare Gabb 
Meekia sella Gabb 
Meckia navis Gabb 
Meretrix arata Gabb 
Mytilus pauperculus Gabb 
Nucula truncata Gabb 
Pachydtsctis sp. 
Pecten tnartinezensis Gabb 
Perissolax brevirostris Gabb 
Pectunculus veatchi Gabb 
Pugnellus hamulus Gabb 
Solarium inortiatum Gabb 
Tellina crqualis (? ) Gabb 
Tellina hoffmajini Gabb 

List of Fossil Species from Todos Santos Bay, Lower California. 

Act(Zonina pupoides Gabb 
Ancyloceras lineatum Gabb 
Astarte matthewsoni Gabb 
Bactilites chicoensis (?) Trask 
Cerithiu)n pilingi White 

Ledo translucida Gabb 
Lunatia avellana Gabb 
Mactra ashburneri Gabb 
Nerita sp. 
Nucula truncata Gabb 

Cerithiuin totium-saiictorum White Ostrea sp. 

Chione varians Gabb Pectunculus veatchi Gabb 

Cinulia obliqua Gabb Pugnellus sp. 

Coralliochama orcutti White Tellitia cequalis Gabb 

Fulguraria gabbi'SSYWX'E. Tellina doides Gabb 

Fusus sp. Trochus eurystomus White 

Gyrodes expansa Gabb Turritella chicoensis Gabb 

The horizon of Todos Santos Bay in Lower California is 
evidently that of the Lower Chico, and is supplementary to 
those of Orange and Los Angeles counties already given. 
Special weight has been attached by White, Stanton, and 
others to the occurrence of Coralliocha7na orcutti, and these 
beds have been generally correlated with those of Wallala, 
on the coast of Mendocino Count}'-, and with the lowermost 
Chico of the Sacramento Valley. At Wallala, Coi'alliockama 
occurs with Solarium ivallala'ense White, Ostrea, Inocer- 
amtis, Pecten, Cylichna, and Turritella. 


It appears that the disturbances of the West Coast have 
been to some extent local, though probably synchronous 
during the Chico epoch. Further evidence of this is also 
found in the deposits of Southern Oregon and Siskiyou 
County, California, where the fauna seems to indicate for 
these localities a different basin. The Oregon Basin was 
probably not directly connected with that of the Sacra- 
mento, at least until during the later Chico. Species that 
belong characteristically to the upper horizon are found 
plentifully common in the two basins, while in the lower 
horizon they are essentially different. There is a closer 
relationship between the deposits of Southern Oregon and 
Vancouver Island than between those of the latter and of 
the Sacramento Valley. There is also a representation of 
Upper Missouri — Colorado — forms in the fauna of Southern 
Oregon, as will be seen in the species of Inoceramus and 
Scaphites, and in some of the ammonites. 

The cephalopods of these lists form one of the most 
striking features. The numerous species of Schloenhachia^ 
alone, almost distinguish this basin from others of the 
Pacific Coast; while to these may be added six species of 
Scaf kites, two species of Acanthoceras, two of Lytoceras, 
besides the aberrant forms, including Hamites, Helicoceras, 
and Heteroceras. 

The Phoenix locality is regarded as representing strati- 
graphically the Lower Chico horizon of the Sacramento, 
yet the differences of the faunas are considerable. 

Attention is also called to the occurrence in the Oregon 
Basin of such forms as Desmoco'as siigaUim, Scaphites 
gillisi, Scaphitcs klamathensis, Goniomya borealis, and P}'o- 
tocardmrn scituluni. Many others will also be noticed that 
seem to have special importance; these will be mentioned 
under the heading of correlation. 

While there are fewer species of cephalopods that con- 
nect these beds directly with those of the Lower Chico in 
the Sacramento Valley, the large number of cephalopods, 

' In the sumrner of iSgg, Dr. J. P. Smith discovered in the Lower Chico of Silverado 
Canyon, Orange County, California, Schlaenbachia oresorunsis and others of this genus like 
those of the Oregon Basin. 


and especially the two species of Acanthoceras, the Lytoc- 
eras species, and others may be taken as evidence of 
a rather low position in the Chico. Moreover, beds of the 
same or of a little later age at Jacksonville, only a few 
miles to the west, contain Lower Chico forms, such as 
Trigonia cequicostata, T. leana, Pecten operctilifortms,'e\.c., 
which have not been found above the Lower Chico. Nor 
is there a single species among this collection that is char- 
acteristic of even the uppermost Horsetown beds. 

The horizon of the Phoenix beds is almost identical with 
that of Cottonwood Creek and Shasta Valley, in Siskiyou 
County. Near the town of Hornbrook (Henley) the Cre- 
taceous beds have a thickness approaching 2,500 feet, the 
lower two-thirds of which is fossiliferous. There are two 
well marked horizons, the lower one containing an abund- 
ance of trigonias and other bivalves and gasteropods, and the 
upper one containing a comparatively large number of ceph- 
alopods, among which are two species of Placenticeras, two of 
Desmoceras, a Pachydiscns, and two species of PhyUocei'as. 
On Willow Creek, a few miles south of the Klamath River, 
and in the strike of the Henley beds, the same horizons occur 
in the same relation. Here the upper zone contains also 
Pachydiscns newberryanus, Desmoceras hoffmanni, Prionotro- 
pts crenulatuni, Scaphites condoni, Hainites artnattini, Des- 
moceras sp., and many others of a Lower Chico aspect. 

The Horsetown Epoch. 

An examination of the Horsetown fauna shows it to con- 
sist in large part of abundant species of cephalopods, espec- 
ially of the genera Desmoceras and Lytoceras ; their relatives, 
Hoflites and Acanthoceras are also common; and there 
are, perhaps, three or four species of Phylloceras, one or 
two of Olcostephamis, at least two species of Nautilus, and 
two of Belemnites. One-half of the entire fauna of the 
Horsetown belongs to the class of cephalopods, and this pro- 
portion seems to be fairly constant throughout. Probably 
when the fauna of the Horsetown strata becomes more per- 
fectly known, the proportion of cephalopods among the 



whole will be increased still more. In the basin of the 
Great Valley they are especially abundant and varied, some 
of them reaching very large dimensions. Among the very 
large forms are Lytoceras argonaiitarmn and Ancyloceras 
^ercostatum. The following is a partial list of those already 
known from the Horsetown beds of the upper Sacramento 
Valley: — 

List of Fossil Species from Horsetown Beds. 

Acanthoceras dispar (?) (d'Orb.) Stol. 
AdcBon impressus Gabb 
Anchiira sp. 

Ancyloceras lineatum Gabb 
Ancyloceras remondi Gabb 
Anisoniyon meeki Gabb 
Archoinya undidata Gabb 
Avicula mucronata Meek 
Avicula whiteavesi Stanton 
Belemtiites impressus Gabb 
Beleimntes sp. 
Chiotie varians Gabb 
Crioceras latum Gabb 
Crioceras percostatum, Gabb 
Cucullcza truncata Gabb 
Cumlia sp. 

Desmoceras betcdanti Brong. 
Desmoceras breweri Gabb 
Desmoceras colusaense, sp. nov. 
Desmoceras dilleri, sp. nov. 
Desmoceras haydeni Gabb 
Desmoceras hoffmanni Gabb 
Desmoceras lecontei, sp. nov. 
Desmoceras merriami, sp. nov. 
Desmoceras subquadratum, sp. nov. 
Desmoceras voyi, sp. nov. 
Diptychoceras Iceve Gabb 
Douz'illiceras mamillare Schloth. 
Eriphyla sp. 

Eripachya hoffmanni Gabb 
Eripachya perforata Gabb 
Exogyra parasitica Gabb 
Fusus aratus Gabb 
Hehcancylus cequicostatus Gabb 
Helicaidax bicaritiata Gabb 
Holcodiscus re\.H. theobaldianus Sioi. 
Hoplites remofidi Gabb 
Inoceramus sp. 
Lima microtis Gabb 
Lima shastensis Gabb 

Liocium punctatum Gabb 
Lunatia avellajta Gabb 
Lytoceras angtilatum, sp. nov. 
Lytoceras argonautaru)n, sp. nov. 
Lytoceras batesi Trask. 
Lytoceras sacya Forbes 
Lytoceras x^. L. sacya 
Lytoceras timotheanum May. 
Meekia sella Gabb 
Nautilus gabbi, sp. nov. 
Nautilus suciaensis, sp. nov. 
Neithea grandicosta Gabb 
Nemodon vancouverense Meek 
Nerinea dispar Gabb 
Nerinea maudensis Whiteaves 
Nerita deformis Gabb 
Olcostephattus traski Gabb 
Olcostephanus sp. 
Ostrea sp. 

Oxytoma mucronata Whiteaves 
Pachydiscus sacramenticus, sp. nov. 
Pecten opercidiforjnis Gabb 
Pinna sp. 

Pleuromya IcBvigata Whiteaves 
Pleuromya papyracea Gabb 
Plicatula varia Gabb 
Phylloceras onoense Stanton 
Phylloceras shastalense, sp. nov. 
Potamides diadema Gabb 
Ptiloteuthis foliatus Gabb 
Ringinella polita Gabb 
Scalaria albensis (?) d'Orb. 
Schlcenbachia inflata Sowerbv. 
Sonnertia stantoni, sp. nov. 
Thetis elofigata Gabb 
, Trigonia czqicicostata Gabb 
Trigofda evansana Meek 
Trigonia rel. T. evansana Stanton 
Trigonia leana Gabb 
Turnus plenus Gabb 


Among the gasteropods of the Horsetown which may be 
mentioned are species of Nerinea, RingincUa, Actaon, 
Anchu?'a, and Helicaulax. Bivalves are represented by 
such forms as Avicula, Plciiromya and Lima, two species 
each, along with others, as Plicatula varia and Thelis clon- 
gata. The following also are typical Horsetown spe- 
cies: Crioceras latum, C . percostatiim, Diftychoceras Icbvc, 
Schlocnhachia injlata, Liociiim ^unctatiim, Potamidcs dia- 
denia (?), Oxytoina imicronata, Ai'chomya undtdata and 
Mithea grandicosta. More than eighty species in all are at 
present known, though it is quite probable that this is not a 
large part of what will be known when the beds are more 
carefully searched. 

The Horsetown fauna in its most typical development is 
of a tropical character, as has already been noticed by sev- 
eral writers. Many of its congeners are numerous in the 
fauna of Southern India. Both have evidently come essen- 
tially from the same source. The southern aspect of the 
Horsetown is seen in the numerous species of Lytoceras, 
Phylloceras, and many of the crioceran and nautilian 
forms. In this respect it contrasts strongly with the 
northern aspect of the fauna preceding it, in the upper 
portion of the Knoxville. 

Comparatively few of the gasteropods and bivalve species 
occurring in this list continue above the Horsetown, though 
some have allies even in the Upper Chico. Probably when 
the Horsetown fauna becomes more completely known the 
transitional forms will appear even less significant, since the 
cephalopods form its ruling class. Perhaps, also, it will be 
possible to separate it into subdivisions, better characterized 
than those of the Chico. Diller and Stanton (1894, P- 445) 
mention as belonging to its upper portion only, Lytoceras 
sacya, Desmoceras beiidanti, Schlcenhachia injlata, Acanthoc- 
eras mamillarc and a few other forms. Likewise there are 
a few that belong especially to the lower portion of the 
Horsetown, among which are Belemnites impresses, Crioc- 
eras percostatiim, Olcostephaniis traski, and perhaps Heli- 
caulax hicarinata and Potamidcs diadema. On the other 


hand, many important species run through the whole of the 
Horsetown, forming connecting Hnks from bottom to top. 

In the basin of the Sacramento the base of the -Horse- 
town division of the Cretaceous has perhaps been well 
placed at the upper limit of the range of Aucella. Few if 
any of the species characteristic of the Horsetown appear 
to extend below this limit, and until this supposition shall be 
proved erroneous the boundary seems to be a practical one. 
It is stated by Diller and Stanton (1894, p. 446) that many 
well known and typical Horsetown species occur within a 
few hundred feet, stratigraphically, of the upper range of 
Aucella, near the Elder Creek section. Below this point, 
however, as one descends the series, they entirely disappear 
or have not been found. Or, with the exception of Belem- 
nites impressus, Lytoceras batesi, Crioceras latum, and two 
or three others, there are perhaps no species connecting the 
Horsetown faunally with the strata containing Aucella, 
while on the other hand, the associates of this genus form a 
separate and distinct fauna. 

The Pa sk cut a Hoi'izon. 

The strata containing Aucella, that is, Knoxville, as 
originally understood, have been made the subject of a 
special faunal study by Dr. Stanton (1895) who has pub- 
lished a somewhat complete list, containing in all about 
seventy-seven species, fifty of which are described as 
new. He remarks that the majority of this number are 
rare; yet even so, this is an unexpectedly large number 
when contrasted with the few species that had formerly 
been known from the Knoxville. Yet had this assemblage 
of species been found distributed throughout the twenty 
thousand feet of strata that have been referred to the 
Knoxville, it would not have seemed surprising, for this 
thickness of strata is twice as great as the entire sum of the 
Horsetown and Chico strata combined. But the most inter- 
esting part of this discovery is not the large number of 
Knoxville species brought to light, but the fact that they 
were nearly all obtained, not from the entire range of twenty 


thousand feet of what was termed Knoxville strata, but from 
the uppermost four thousand feet of them. The seventy- 
seven species enumerated, all of which, with the exception 
of two or three species of Aucella, are apparently confined 
to this relatively small stratigraphical range, are almost 
equal in number to the eighty or more species that are thus 
far known from the six thousand feet of Horsetown strata, 
where the individuals are far more abundant. In fact, the 
actual thickness of strata through which this new and distinct 
fauna ranges is not yet definitely known, though from the 
statements made in regard to the locality and position of the 
different species, we learn that the great majority of them 
have been found in or near the sections studied in the 
Sacramento Valley, and that the stratigraphical range is 
rarely if ever given as greater than three thousand feet 
below the upper limit of the Aucella range. With the 
introduction of this new fauna at that horizon the Atccellcs 
gradually diminish, until at the next immigration of species 
they entirely disappear. Stanton says of this fauna: ''All 
but seven of the species are mollusca, including thirty-three 
species of Pelecypoda, one species of Scaphopoda, eighteen 
species of Gasteropoda, and eighteen species of Cephalo- 
poda, of which fifteen are Ammonoids, and three are 
Belemnites. The other seven species include five Brachio- 
pods and two Echinoderms." So far as known, the cephalo- 
pods contain a single species each of Dcsmoceras, Lytoceras, 
and Phylloccras, forms which are so numerous in the Horse- 
town, while Hoplites is represented by five species and 
Perisphmctes by one. 

The two species of Olcostephanus are both new and have 
not been found in the Horsetown. An important feature of 
the Gasteropoda is the large number of Turbo species, six 
species of this shell being described. Two species of 
Hypstpleu7-a, and three of Cerithium are known. Nothing 
particularly characteristic is to be noticed with reference to 
the bivalves, most of which, with the exception of Aucella, 
have allies among the fauna of the Horsetown. The 
Brachiopoda, however, deserve mention, the five species 
being, perhaps, peculiar to this fauna alone. 


The fauna here described is especially well represented 
in the vicinity of Paskenta, Tehama County, where a few 
localities have yielded most of the described species. Other 
localities that have furnished a number of the species which 
have been included in this list appear to belong to the same 
horizon. One is a locality of white limestone along Sulphur 
Creek, Colusa County, from which the following species 
have been obtained : RhynchoneUa whitneyi, Modiola major, 
Pecten coniplextcosta, Lucina coliisa'ensis, Atresius Ih-attis, 
and Turbo cohisaensis. Other species from evidently the 
same horizon in the near neighborhood may be added, as 
Astarte trapezoidalis, Turbo morganensis, and Turbo 

The exact position of this limestone in the series of 
AuceUa-\)^2iXm^ strata has not been determined, but it 
appears to be interstratified with shales containing Aucella; 
and since many of the same species have been found near 
Paskenta, in thin layers and lenses of limestone, it seems 
pretty evident that the same horizon is represented in both 
localities, and that the strata of both belong near the top of 
the upward range of Aucella. 

Southward of the Sacramento Valley scattered occur- 
rences of yl?^c^//rt-bearing rocks are found of which but 
little is yet known. One mile north of Berkeley, Alameda 
County, Aucella and Belemnites have been found in dark, 
sandy shales, and near by is a bed of light colored lime- 
stone having a fetid odor, from which Dr. J. C. Merriam 
and Charles Palache obtained Modiola major, Lucina cohi- 
saensis, Pcctcn complexicosta, Cardinia (?), Myoconcha (?), 
Turbo, Atresius liralus, and other forms resembling Pas- 
kenta species. At the eastern edge of the town, almost in 
the strike of these rocks, are sandy beds that will be 
referred to again, and which Dr. Merriam regards as 
undoubtedly of Chico age. 

Farther south, in the vicinity of Haywards, fossiliferous 
shales occur from which was obtained a specimen of Crioc- 
eras -percostatum, which is now in the collection of the 
California Academy of Sciences. This locality is classed 
as probably of the Knoxville (Paskenta) epoch. 


In the Alum Rock canyon, a few miles east of San Jose, 
Dr. J. P. Smith has found Ancella fiochi associated with 
Beleinnites; and in the canyon of Stephens Creek, a few 
miles west of the same town, he has reported a similar bed 
of dark, siliceous shale containing Ancella fiochi. 

Still farther south, near Gilroy, on the road from San 
Jose to Santa Cruz, Ancella crassicollis has been found by 
Dr. Smith and others, along with an Olcostepkanus, and 
other undetermined species. 

The most southern locality in which Ancella has yet 
been discovered in California is a few miles north of San 
Luis Obispo. Dark, Ancella-heanng shales occur in the 
hills to the west of Santa Margarita, where in one exposure 
of them on the Eagle Ranch the slender form of Ancella 
piochi is very abundant. An ammonite, probably an Hop- 
lites, was also obtained at this locality. 

While not exactly demonstrable from our present knowl- 
edge, it yet seems evident that a more or less connected 
line of deposits of Knoxville (Paskenta) age can be traced 
along the eastern border of the basin of San Francisco Bay 
from beyond San Jose northward. This line of deposits 
will be be seen to include Gilroy, Alum Rock, Haywards, 
and the exposures near Berkeley. The topography of the 
country suggests also that it might even be extended by a 
little exploration to connect with deposits of the same age in 
Napa Valley, at Sulphur Creek, and even to Knoxville itself. 

One other isolated locality deserves to be mentioned; 
that upon the northern flank of Mount Diablo. Mr. Turner 
discovered here Ancella-hearmg shales in contact with 
metamorphic rocks of a still older series. The fauna of 
these shales consists of Ancella which he refers to the type, 
A. mosqnensis, Bclcmnites, Inoccramns, and a few species 
of gasteropods. 

It has already been noticed that in the strata referred to the 
Paskenta horizon beds and lenses of limestone are common ; 
and as usual, according to Turner, here, too, all the fossils 
with the exception of Ancella are found in layers of lime- 
stone. It seems most probable, therefore, from the foregoing 


statements, that all of these scattered localities contain 
strata entirely equivalent to that of Paskenta, since below 
this horizon in the sections of the Sacramento Valley no 
ammonites have thus far been discovered. This horizon, 
moreover, represents exactly and completely all that should 
be included in the Knoxville as it w^as first described by 
White (18S5). 

Three things should be noticed regarding the Knoxville 
horizon as thus understood, showing its faunal relations to 
that of the Horsetown, First, it is characterized by an 
almost distinct fauna, very few species of which appear to 
have been found in the Horsetown portion of the series, 
while in each the total number of species is rather large. 
Second, the typical and varied Horsetown fauna occurs 
very near, though above, the upward limit of the Knoxville, 
and appears there in a somewhat striking contrast with it. 
The transition is sudden. Third, the Horsetown fauna, 
with the exception of three or four species already men- 
tioned, does not seem to have been, and hardly could have 
been derived from that of the Knoxville. The types are 
entirely different. Dr. White believed the Knoxville fauna 
to be decidedly boreal in character, and referred particu- 
larly to the genus Aticella in support of this view. The 
same opinion has been held by others, and Dr. J. P. Smith 
states that some of the ammonites have their nearest alHes 
in the north of Europe. Reference has already been made 
to the equally manifest tropical aspect of the fauna of the 

Another circumstance that appears to coincide with this 
faunal demarcation, and which forms a strong corrobora- 
tive testimony in support of the conclusions to be drawn 
therefrom, will be discussed later in connection with the 
distribution of the Horsetown beds and the general occur- 
rences of intrusive peridotites. 

The Sub-Knoxville Horizon. 

One of the most important contributions made by Diller 
and Stanton to our knowledge of West Coast geology was 
in the discovery of an immense thickness of strata below the 


horizon of the true Knoxville, which for lack of a better 
name is here designated as the sub-Knoxville. Below the 
Knoxville (Paskenta) horizon in the Tehama and Shasta 
sections there are at least 15,000 feet of conformable strata 
from which but few organic remains other \}i\2Ln Aucella have 
been obtained. It is not yet possible to say where the exact 
limits between this and the Knoxville horizon may be drawn, 
and indeed it may not be possible to establish one more than 
theoretically in these sections. Still there appears to be 
quite sufficient evidence thatthe Knoxville, as here restricted, 
was inaugurated by some profound movements, felt else- 
where, if not in this basin itself. 

The sub-Knoxville horizon, that here forms at least one- 
half of the entire conformable series, has not yet been 
clearly recognized outside of the Sacramento Valley, either 
in California or Oregon. Nearly, if not quite all the occur- 
rences of Aucel/a-hQaring rocks in the Coast Ranges have 
shown themselves by their fossil remains, other than 
Auce//a, to belong wholly to the Knoxville (Paskenta) 
horizon, and have not been shown to exceed it either in 
thickness of strata or in faunal contents. If the sub-Knox- 
ville horizon has really any equivalent in other portions of 
the State, they ought to be found outside of the borders of 
the Great Valley, beyond the margins of recognized Cre- 
taceous deposits; and it is not unlikely that some of the 
stratified rocks of the Klamath Mountains will prove to be 
their complete contemporaries. 

VI. Disturbances of the Period. 
I. Distribution of the Horsetown Beds. 

In dealing with the two horizons of the Chico an attempt 
was made to show the wide-spread disturbance that had 
intervened and which was locally accentuated. The evi- 
dence for this was first a considerable faunal change in 
passing from Lower to Upper Chico, and second a general 
lack of coincidence in the distribution of Upper and Lower 


Chico deposits. It might also be said that the Lower Chico 
has a wider transgressional expansion than the other. 

Quite similar relations exist also between strata of the 
Lower Chico and Horsetown epochs, with the difference, 
however, that in California the Horsetown is but little known 
outside of the Sacramento Valley, or to express it more 
accurately, outside of the immediate borders of the Great 
Valley. Its distribution is apparently restricted, just as are 
the deposits of the sub-Knoxville, almost entirely to this 
basin, where it builds with the strata of the lower and upper 
horizons of the Cretaceous a more or less continuous series. 
The fact is a remarkable one, that throughout the Coast 
Ranges west and south of the Great Valley, few if any 
deposits of Horsetown age are found. Those that have 
been satisfactorily shown to belong to this epoch lie upon 
the immediate borders of the Great Valley, and they have 
yet to be found south of the latitude of Benicia and the 
junction of the two great rivers of this basin. 

There is no assignable reason why deposits of the Horse- 
town should not be found within the boundaries of the San 
Joaquin Valley, but as yet the nearest approach to this fauna 
that has been discovered south of the latitude named is from 
a locality lying about eight miles east of the town of Liver- 
more, at Arroyo del Valle, some miles southeast of Mount 
Diablo. This is a locality discovered many years ago by 
Dr. Lorenzo G. Yates of Santa Barbara, who obtained 
from this place a large number of ammonites now in the 
collections of Stanford University. Among them are the 
following species as determined by Dr. J. P. Smith: — 

Baculites chico'ensts Lytoceras cf. L. tinwtheaniim 

Belemnites sp. Pachydiscus cf. P. newberryayius 

Cinulia obliqua Pachydiscus cf. P. suciaensis 

Desmoceras hoffmanni Phylloceras onoense 

Desmoceras cf. D. selwynanimi Phylloceras raniosiini 

Hoplites remoiidi Placenticeras californicuni, sp. nov. 

Lytoceras alamedense Placenticeras pacificmn 
Lytoceras batesi 

It can not be denied that the fauna of this locality shows 
a strong intermingling of Horsetown and Lower Chico 


species. In this respect it resembles other locaHties within 
the borders of the Great Valley. The succession of disturb- 
ances inaugurating the Chico was here so little felt as to 
allow pre-existing species to survive locally. The Chico 
faceies of this locality, is, however, represented by such 
forms as Pachydiscus newberryanus., P. suciaensis, Baculites 
chico'ensis, Cinulia obliqtia, and also Placenticeras califor- 
niaini and P. facijicwn have been found elsewhere in 
undoubted Chico deposits, and they have been found in no 
other deposits. The former occurs in the Lower Chico 
beds of the Forty-nine Mine, Jackson County, Oregon, and 
in exactly the same horizon at Henley, Siskiyou County, 
California, along with P. pacificum; while Dr. J. P. Smith 
states that P. californicum has been found in the Lower 
Chico of the San Fernando Mountains, Los Angeles 
County, California, and that Mr. F. Rolfe has found in 
the Lower Chico of Silverado Canyon, Orange County, 
California, P. pacijiacni associated with typical fossils of 
this epoch. 

2. The Chico-Knoxville Unconformity. 

This occurrence of Lower Chico strata seems the more 
important because upon the northern flanks of Mount 
Diablo, only a few miles away, Chico beds are found 
apparently conformable upon AucclIa-hediYmg shales form- 
ing a series of several thousand feet in thickness. These 
Mount Diablo deposits were first described by H. W. Tur- 
ner (1891) and afterward discussed by Stanton (1895, 
p. 21, etc.). Mr. Turner believed that a portion of this 
conformable series represented the Horsetown, but was 
unable to prove it to his own satisfaction. The upper por- 
tion of the series has yielded Baculites chicoensis and a few 
other Chico forms, and the lower portion is the horizon of 
the Knoxville discussed a few pages back. Stanton esti- 
mated that the intervening strata had a thickness of about 
five thousand feet, in regard to which he says: "If the 
horizons are all represented, then sedimentation was here 
very much less rapid during a part of the Cretaceous 


than it was one hundred and fifty miles north, in 
Tehama County; while if the Horsetown and a part of 
the Knoxville beds are really lacking, there must have been 
a local uplift in the Mount Diablo region which did not 
involve the Coast Ranges farther north." The Chico beds 
are here the Upper Chico and much of the five thousand 
feet of strata intervening between this and the Aucel/a beds 
must evidently belong to the Chico group, since on the 
south side of the mountain the Lower Chico occurs. One 
is forced, then, to accept Mr. Stanton's second alternative, 
with the amendment, however, that the uplift, while local, 
was only a local accentuation of a disturbing influence much 
more general throughout the Coast region. 

It will be interesting to remember here the cases of un- 
conformity discovered by Fairbanks (1895, p. 426, etc.) 
between Chico and Knoxville beds in San Luis Obispo 
County, in reference to which he says: "The Knoxville 
(Paskenta) is bordered on the west by a great dike of ser- 
pentine, while on the east a nearly hidden axis belonging to 
the Golden Gate (Franciscan) series projects through it in 
numerous places. The Knoxville presents a very much 
disturbed condition, partly due to the dikes of serpentine. 
The Chico, consisting almost wholly of heavy bedded sand- 
stone, rises on the eastern slope, overlapping the Knoxville 
shales and capping portions of the first line of hills." 
Points at which this unconformity is particularly clear he 
has discussed more in detail. One was found upon the 
Eagle Ranch, west of Santa Margarita, and another a 
few miles to the northwest, where almost undisturbed 
Chico sandstones rest upon highly tilted Knoxville shales 
with Aticella fiochi. Concerning this region Dr. Fair- 
banks (1898, p. 560) says in a later paper, speaking of the 
Chico: " Fossils are not abundant but they were found 
in sufficient numbers in the Santa Lucia Mountains to 
demonstrate the age of the formation. In the latter locality 
the sandstone terminates downward in a conglomerate which 
is in places one hundred feet thick, resting either upon the 
Knoxville shales or the Golden Gate series. The relation 


to the Knoxville shales was carefully examined at many 
points along the northern slope of the Santa Lucia Moun- 
tains and a conclusion was reached which is in accord with 
one already published, namel}^ that the Lower and Upper 
Cretaceous are, in this region at least, separated by an 
unconformity. This is shown by a marked discordance in 
the dip between the two and the extension of the upper 
across the strike of the lower, etc," The Chico here 
described is that of the upper horizon as previously shown. 
And what has been so clearly demonstrated in the region 
south of the Great Valley is exactly paralleled beyond its 
boundaries northward in California. 

In a former paragraph mention was made of AuccIIa beds 
occurring at the base of the Cretaceous section in the Sis- 
kiyou Mountains, In the collections of the State Mining 
Bureau in San Francisco is a specimen of calcareous rock 
about two pounds in weight, consisting of a compacted mass 
of AiLceUa fiochi shells, and bearing upon its label, " from 
Siskiyou County, California." Miss M. Hearn of Yreka, 
from whom this specimen was obtained, states that it came 
from the south side of the Siskiyou Mountains, and from a 
locality from which many Chico fossils have often been 
collected, and one which is included in the preceding lists 
of Chico fossils from that region. Much of the Cretaceous 
series along Cottonwood Creek, Siskiyou County, has the 
appearance of the soft clay shales of the Knoxville beds on 
Cottonwood Creek, Shasta County; and to one familiar 
with these shales, and with the unconformity between Chico 
and Knoxville found far southward, it is not surprising that 
Aucella beds should be found here also unconformably 
related to the Chico. How extensive this unconformable 
relation may be throughout the coast region is not yet 
known; but from the observations of Dr. J. C. Merriam 
(1901) in the basin of the John Da}'^ River, it appears to 
have a wide range in the Oregon Cretaceous basin. He 
says: " In the valley of Bridge Creek a great thickness of 
conglomerates, sandstones and shales is exposed at Mitchell, 
eighteen miles northwest of Spanish Gulch. The upper 


portion of this section much resembles the Cretaceous at 
Spanish Gulch, while the lower part, consisting of soft dark 
shales with an occasional thin, hard stratum, is an exact 
duplicate of the Knoxville, as it is usually developed in 
California and Southern Oregon. The total thickness of 
the section is hardly less than 3,500 to 4,000 feet, of which 
the shales probably make up more than one-half. At the 
lower end of the Mitchell Knoxville section the shales dip 
westerly for a short distance, but the west side of the anti- 
cline is covered by Tertiary formations." The fossils of 
the upper portion of the section show it to be of Lower 
Chico age. 

3. The Peridotite Intrusions. 

The relations of the serpentines of the Coast Ranges to 
both the Knoxville (Paskenta) and the Chico strata form 
another convincing proof of the unconformity of the Chico 
upon the former. It is well known that the peridotites 
from which the serpentines have been derived have been 
intruded into the Knoxville beds at many places in the 
Coast Ranges, and that this has happened especially, also, 
throughout the very region from which the Horsetown 
strata are entirely missing. A few of these cases may be 
given, though an extended and complete list of them, that 
have from time to time been noticed, would be superfluous 
for the purpose of this paper. 

On the map of the Great Western Quicksilver Mine, 
Napa County, published by Becker (1888, p. 358), tongues 
of serpentine are shown penetrating the " Neocomian" 
shales. Such occurrences are said to be abundant, and so 
closely and generally are serpentine and Knoxville shales 
associated in that region as to suggest to Becker the deri- 
vation of the serpentine from sedimentary rocks. He 
(Becker, 1888, p. 121) says: "Highly inclined strata 
strike into serpentine areas in such a manner as to wholly 
preclude the supposition that the serpentine represents an 
earlier mass." At Mount Diablo, also, Mr. Turner (1891) 
has shown similar dikes of serpentine cutting the Knoxville 

(5) November 24, 1902 


shales. In Tehama County, the shales are said to dip 
steeply away from a mass of serpentine at their base, which 
has evidently been a disturbing agent. H. W. Fairbanks 
has repeatedly spoken of serpentine cutting the Knoxville 
shales in the southern Coast Ranges, as near San Luis 
Obispo and other neighboring points. Dr. J. P. Smith 
states that he has observed serpentine intrusive in the 
Aucc/Za-heanng shales on the Whitney ranch, some miles 
southwest of Gilro}^ Santa Clara County. 

Exactly similar relations are found in connection with 
strata of the same age at Riddles, Oregon, where a belt of 
Cretaceous rocks five miles in length is bordered on the 
west by serpentine and peridotite. It is thus seen that 
from San Luis Obispo County northward far into Oregon 
the Knoxville is everywhere penetrated and disturbed by 
dikes and masses of serpentine and accompanying perido- 
tites; and it is exactly from this Coast Range region in 
which serpentine is common that the Horsetown strata are 
entirely absent. (Turner, 1891, map opposite p. 383.) 

At many places in this same region Chico beds are also 
found in contact with the serpentine; but it has not been 
stated that they have ever shown evidences of having 
been even slightly altered or disturbed by the peridotites. 
Indeed, quite the contrary is usually the case, as Fairbanks 
has already stated. 

4. The Chico Overlap. 

This serpentine intruded country does not form a narrow 
strip bordering the basin of the Great Valley, but it extends 
from that basin westward, frequently to the ocean. It is 
many miles in width, and extends from the southern portion 
of California northward far into Oregon. In the latitude 
of southern Mendocino County this intrusion has thrown 
the Horsetown entirely out of the series in the Coast 
Ranges west of the Great Valley, while Chico strata are 
found upon both sides of the peridotite belt, at Wallala, 
upon the seaboard and in the Sacramento Valley. The 
position of these Wallala beds, which have been classed as 


Lower Chico, lying as they do near the low coastal border 
of a large area of Knoxville which has been uplifted by this 
intrusion, accords well with the unconformity which else- 
where exists between them. 

On the other hand, the Chico beds, representing the 
great overlap succeeding these intrusions, are known in 
many cases to rest directly upon masses of serpentine in 
an undisturbed position. This is particularly true in north- 
ern California. Near Yreka, Siskiyou County, a belt of 
serpentine and peridotite crosses the country in a south- 
westerly direction, passing beneath the town. At a dis- 
tance of one to three miles on either side of the town are 
to be seen the fossiliferous and unaltered beds of the 
Lower Chico, resting in nearly a horizontal position upon 
the serpentine. Other similar occurrences have also been 
noticed. South of Weaverville, in Trinity County, the 
Lower Chico occurs, and appears to have some similar 
relation to the serpentines lying to the north. Similar facts 
have also been noticed in the southern Coast Ranges. 

Thus every class of evidence required to fully demonstrate 
the post-Knoxville disturbance seems to have been satisfac- 
torily shown to exist. Not only have the Chico deposits 
been found resting unconformably upon the Knoxville, but 
the Horsetown is evidently absent from wide regions in 
which both of the other members occur; and at the same 
time copious masses of eruptive rocks are found exactly in 
the position to coincide with the intervening disturbance and 
accordingly with the unconformity between them ; and it 
has also been shown that beds of the Lower Chico rest in 
an undisturbed position directly upon areas of the same 

Vn. Correlation of Deposits. 

Without attempting to settle the difficult problems of 
correlation, there are a few observations that may be made 
relative to results that are not beyond the range of data 
already known. For distant and unrelated provinces pos- 
sibly no correlation will ever be attained that is entirely 
satisfactory; and that is not the aim of this paper. 


1. The Sacramento Sections. 

The Sacramento sections, on account of their complete- 
ness and simple stratigraphic succession may well become 
standards of great value for the correlation of other Creta- 
ceous deposits of the greater Pacific province ; but only 
when they themselves become very much better known. 
For the present, criteria must be sought by means of which 
these sections may be studied. It is evident, too, that the 
greater stratigraphic range of species in this basin will 
always be a perplexing element in using any of these 
sections as a standard for comparison. For that reason, 
the plan of selecting deposits beyond the limits of this 
basin, in which there are clear evidences of disturbance, 
has here been attempted. 

For the Chico epoch this method is reasonably satisfac- 
tory, and with our increasing knowledge of the Cretaceous 
deposits of the Pacific Coast, it will become more so. Pos- 
sibly when the Horsetown faunas of California and Oregon 
become better known the same method will be found 
equally applicable. 

In correlating widely separated deposits by purely 
paleontological means, the safest conclusions are reached 
by considering whole faunas, or the ruling classes, and 
supplementing such evidence by the more direct comparison 
of species, some of which have a wide geographical range. 

It is a surprising fact that the cephalopod faunas of the 
Pacific Coast basins of America are not more closely 
related, while some of them have comparatively strong 
affinities with those upon the opposite side of the Pacific, 
namely, of eastern and southern Asia. Already there are 
many species known, either identically or representatively 
common to the Cretaceous of Southern India, and to one or 
more of the basins of the Pacific Coast of America; and 
the same is true of the Cretaceous deposits of Japan. 

2. Equivalents of the Chico. 

It has been the custom of most writers upon the subject 
to regard the Upper Cretaceous rocks of Vancouver and 
the neighboring islands as homotaxial equivalents of the 


Chico of California. Mr. J. F. Whiteaves (1876-84, p. 179) 
has published an extended list of species from the fossilifer- 
ous beds of the Nanaimo and Comox sections, in which he 
indicates the horizon of each, and its occurrence, when 
known, in the Chico beds of the Sacramento Valley. 

Of the fifteen species of cephalopods occurring in these 
lists, only three are known to occur also in the Chico. 
Nearly one-half of the gasteropods and almost the same 
proportion of the lamelHbranchs are abundant or common 
in the Chico of California. The occurrence of the inter- 
esting species, Inoceramus labiatiis, in the Lower Chico of 
California, and in "Division ^" of the Queen Charlotte 
Islands section, perhaps shows the equivalence not only 
of these horizons, but also indirectly the equivalence of the 
Nanaimo beds, and the uppermost beds of Queen Charlotte 
Islands. It is an unusually interesting point, and one that 
can furthermore be considerably strengthened by evidence 
that is not quite so direct but entirely conclusive. It serves 
also to correlate more satisfactorily the deposits of the 
Pacific border with those of the interior basin. 

Inoceramus labiatus is abundant in the upper portion of 
the Colorado group, but is rare outside of that horizon. In 
the deposits of the Pacific border it is apparently confined 
to the Lower Chico and to beds homotaxially equivalent. 

The upper beds of the Oregon Basin, including those that 
have been referred to as the Phoenix and Henley beds, hav- 
ing a stratigraphic position equivalent to that of the Chico, 
contain not only Inoceramus labiatus, but also other forms 
still more trustworthy for purposes of correlation. 

In the three basins, therefore, of the West Coast, the 
Chico, the Nanaimo, and the Phoenix and Henley beds may 
be shown to be homotaxially equivalent, and equivalent also 
to the beds of the Colorado group in the interior basin. 

The faunal elements that appear to connect these hori- 
zons in the Pacific border basins contain not only a general 
paralleHsm of the broad classes of mollusks, but also repre- 
sentative genera, and not a few species in common. The 


proportion of cephalopods is essentially the same in each. 
Although in the case of the Phoenix beds it seems somewhat 
large, this is due rather to the neglect of the lower orders 
than to their absence. It is not far from the truth to say 
that the ratio of the cephalopods to the others is, in general, 
one to five. The genera most commonly present in this 
class are Pachydisciis, JBaculites, Hamites, and others of the 
aberrant types. A few species of Desmoccras, Lytoceras^ 
and at least one species of Phylloccras are known to occur. 
Phylloceras ramosum (Meek) is common to the three basins, 
occurring at Mount Diablo, the " Forty-nine Mine," and in 
the Nanaimo beds. Baciilites chicoensis is reported from the 
Chico and Nanaimo groups along with Pachydiscus nciv- 
berryaiius, and possibly P. sucta'ensis ; while the Nanaimo 
and the Phoenix beds are further connected by Lytoceras 
jukesi, and by representative species of Hamites and Bacu- 
lites. Similarly the connection between the Chico and the 
Phoenix beds is reinforced by the occurrence in each of 
Schlanhachia chico'ensis{^x'A.^\C), and an Acanthoceras related 
to A. rotomagense. Undoubtedly, however, the strongest 
connections between the three basins are shown by the 
large proportions of gasteropods and bivalves, very many of 
which are specifically common to all of them. In addition 
to Inoceramtis lahiatus, which is common to all the basins, 
there is also /. crippsi, which is probably identical with 
/. whitneyi. Two species of Trigonia, — T. tryoniana and 
T. evansana, — are found alike in each of the three basins. 
But the true relations can only be fully presented by com- 
parative lists of species, such as the one published by Whit- 
eaves, which cannot here be reproduced. Of the thirty or 
more species there listed as common to the Nanaimo and 
the Chico beds, more than half are found in the Phoenix 
(and later) beds of the Oregon Basin. Others, common 
only to the Phoenix and Nanaimo beds, and others, occur- 
ring only in the Phoenix and Chico beds, still further 
augment this number; and this is exactly what would be 
expected in beds synchronously deposited in different 


It has been pointed out by Whiteaves and others that the 
overhip of the Nanaimo strata in the Vancouver basin 
accompanied a subsidence of the Cordilleran region which 
resulted in the final connection of the Pacific and interior 
waters. This has been conclusively established not only 
by the presence of Inoceramiis labiatus, a form very abun- 
dant in the upper portion of the Colorado group, occurring 
also in the upper beds of the Queen Charlotte Islands, but 
by others, 

Whiteaves (1876-84, p. 188) has published a list of related 
species, occurring in the upper beds of Vancouver and in the 
Cretaceous of upper Missouri, which are intended to show 
the commingling of faunas of this period. To these lists 
may now be added other important forms from the later Cre- 
taceous beds of Southern Oregon. No less than six species 
of Scafhites, eight species of Schlocnbachia, two species of 
PIacentice?'as, five species of Inoceramus, and many other 
forms, have been found here that strongly recall the fauna 
of the Colorado group. Nor is the resemblance one of 
only general groups and genera. Many of the species 
are either very closely related or are identical. Besides 
Inoceramus labiatus, the list includes a species resembling 
/. mytiloides Con., Prionocyclits branneri (very close to 
P. zuoolgari (Mant.) Meek), Scaphites gillisi (still more 
closely related to S. warreni M. & H.), and S. klamath- 
ensis, which may be an equivalent of S. larvceformis 
M. & H. from the lower portion of the Colorado. Other 
members of the genus Schlocnbachia resemble Prionocychis 
ivyomingensis. These species have been given other spe- 
cific names; yet the very close affinities with those of the 
Colorado group can hardly be doubted. 

The close resemblances in the faunas of the more north- 
ern Pacific border basins and those of eastern Asia are 
shown in the following parallel lists from the Upper Creta- 
ceous of the Oregon Basin and that from the Island of 
Ezo (Jokoyama, 1889) : — 


Island of Ezo. Oregon Basin. 

Desmoceras gaudama (pars), rel. Desmoceras hoffmanni Gabb 
Desinoceras siigatiiui = Desmoceras sugatmn Forbes 

Lyioccras sacya (pars) = Lytoceras sacya Forres 

Lyioceras sacya (pars) cf. Lytoceras jukesi Sharpe 

PachydiscHS arrialoorensis cf. Pachydiscus henleyensis, sp. nov. 

Phylloceras villcdce, near rel. Phylloceras ramosuvi Meek 

Inoceranius naiiinaniii rel. Iiwceraniiis klatnathcnsis, sp. nov. 

Inocerainics sp., rel. Liioccrainiis ivhitneyi Gabb 
Ciicullcea sachalinense {!), cf. CuciUUca truncata Gabb 

Nucula picttiraia, cf. Nucula truncata Gabb 

The Turonian aspect of at least the upper portion of the 
Chico is very clear, as has already been pointed out by 
different writers. It is further emphasized by some of the 
above forms, which are known for the first time from the 
Pacific border province in the Phrenix beds of Southern 
Oregon. And to these may be added the great develop- 
ment of the gasteropod and bivalve classes and many 
aberrant forms of Helicoceras and Hamitcs, among which 
is to be noticed an Jlclicoceras related to //. retisianwm 
d'Orb., while the Turonian species, Inoceranuis lahiatus^ 
and many others ally these beds to the Turonian of Euro- 
pean Cretaceous. But there are also contained in them 
many forms that belong to a higher, as well as a lower, 
horizon. BaciiUtes chico'cnsis and B . fairbanksi are both 
closely akin to B. vagina Forbes, which is thought to be a 
Senonian species. Numerous forms of Pachydiscus are 
found in the Chico and its equivalents which would be 
expected in Senonian equivalents; while the large develop- 
ment of gasteropods and lamellibranchs shows a late period 
of the Cretaceous. On the other hand, there are not a few 
undoubted Cenomanian forms in the Lower Chico beds 
which incline one to refer them to a lower position than the 
Turonian. Among such forms are certain species of 
Acanthoceras and some of the forms of Schlocnhachia. 

In this connection also it ought to be said that the closest 
relationship seems to exist between some of the forms of the 
Lower Chico and some from the Ootatoor beds of Southern 
India. Inoccrainus labiatiis is associated with Acanthoceras 


navicular e Mant., both in the Phcenix beds and in the 
Ootatoor; but the Ootatoor beds have been correlated 
with the Cenomanian, and both these forms are hkewise 
found in rocks of that period in Europe. On the whole, 
however, the strongest affinities are undoubtedly with the 
Turonian; and if one remembers the great stratigraphical 
range of some of the species of the Sacramento Valley, it 
does not seem remarkable that Cenomanian or even Gault 
types are found occasionally in the Chico. 

Mention might be made here of the Upper Cretaceous 
beds occurring on the west coast of Chile. Whether these 
beds are to be correlated more closely with the Upper or 
Lower Chico has not been very satisfactorily ascertained, 
but a few of the species found there indicate a rather low 
horizon. Phylloceras ramosiim occurs in the lower part of 
the Chico in all of the more northern localities ; Desmocei'as 
(Piizosia) darwini has a close ally in D. ashlandicutn of the 
Phoenix beds; Lytoceras varuna is found in the Ootatoor 
beds of India; and the Hamites, resembhng //. cylindraccus 
de France, is also in accord with the lower horizon. 

The exact position of Lytoceras kayei in the Californian 
beds has unfortunately not been learned. It is only known 
to come from the Chico of Mount Diablo. It appears, 
therefore, that along the Pacific Coast of America from 
British Columbia southward to Chile the overlap of the 
later Cretaceous, including the Lower Chico and its equiv- 
alents, is satisfactorily seen in most, if not all, of the widely 
separated locahties of southern Vancouver, Rogue River 
and Sacramento valleys, Southern California, Todos 
Santos Bay, and Quiriquina Island, on the coast of Chile. 
It seems hardly probable that a movement of so great 
north and south range should be unaccompanied by parallel 
disturbances in regions lying so nearly contiguous as that 
of the interior basin ; and there appears to be both faunal 
and stratigraphical evidence that contemporaneous move- 
ments occurred in the two regions on opposite sides of the 















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Phoenix and 
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3. Equivalents of the Horsetown. 

There are fewer known deposits of the Horsetown epoch 
upon the borders of the Pacific, and they have thus far been 
less studied than either the lower or upper horizons; yet 
its equivalents are recognized in each of the Pacific border 
basins, although in the Oregon Basin the typical cephalopod 
fauna of the Upper Horsetown has not been shown to exist. 
The close relationship, however, of the Horsetown and at 
least a portion of the Queen Charlotte Islands section is 
very much more clearly seen. Several species of the Upper 
Horsetown fauna occur in a portion of "Division C " of 
this section, and leave us accordingly but little room to 
doubt their equivalence. 

Among the connecting elements may be noticed the gen- 
eral abundance of cephalopods, and especially those of the 
genera Lytoceras and Desuioceras. Both these deposits have 
many of the species and general cephalopod fauna of the 
Ootatoor, as has been more especially emphasized by 
Kossmat (1895), though previously recognized by others. 
Among the forms common to the three regions, California, 
British Columbia, and India, are Lytoceras ttmotheanuvi, 
L. sacya, Desmoceras betidanti, D. planulattim, Sckhrn- 
bachia injiata, and others apparently identical. As in the 
Chico, so here additional species are found still more 
closely connecting either two of these basins. Lytoceras 
batesi, Desmoceras breweri, Nautilus sticiaensis, Ancyloceras 
reniondi, species of Belemnites, and many other molluscan 
forms are common to both the Sacramento and the Queen 
Charlotte Islands sections. Schloenbachia propivgua is re- 
ported from the Queen Charlotte Islands and occurs in the 
Ootatoor beds. Forms connecting the Ootatoor and the 
Horsetown are still more numerous. Among them are 
probably the following: Phylloceras velledce (?=/'. ono'cnse 
Stanton), Stoliczkaia di'spar, Lytoceras cala, Holcodiscns, 
aff. H. theobaldiamis StoL, Desmoceras voyt, aff. D. hiti- 
dorsatiis, and perhaps others. 

Kossmat correlates the Ootatoor horizon and its equiva- 
lents on the West Coast of America with the Cenomanian, 


and there can be no doubt that many of the species do favor 
that determination. At the same time, however, it must be 
admitted that many of them are also more closely allied to 
forms of the Gault. 

It has been stated by R. T. Hill (1893), that in the Cre- 
taceous deposits on the eastern border of the Cordilleras 
a distinct unconformity exists between the strata of the 
Comanche series and those of the Upper Cretaceous. 
Rocks of the Dakota epoch are absent from large areas, 
indeed, from the whole region extending from eastern 
Texas to Wyoming and westward; while, at the same time, 
there is evidence of a land-mass covering this belt from 
which have been derived the littoral conglomerates of the 
Dakota lying to the eastward. Furthermore, there is a 
marked difference, both lithological and faunal, between 
the deposits of the Comanche and those of the Colorado 
and later groups, which extend far beyond the boundaries 
of the Lower Cretaceous, reaching northward beyond the 
region of the Upper Missouri. The rocks of the Comanche 
series, consisting largely of marls and limestones, indicating 
deep water conditions, are followed by clays and shales 
and coarser detrital material, such as could only have been 
deposited in shallow water. 

The faunal differences are very great, although they 
cannot be more than referred to here; yet it is worth while 
recalling the comparisons that have been made between 
these faunas and their contemporaries upon the Pacific 
border. Stanton has especially emphasized the contrast 
which is apparent betw^een the faunas of the Comanche 
and the Shasta groups. It is not certain to what extent his 
epitomized diagnosis is applicable for this purpose, since 
he has included in the Shasta formation the whole of the 
Horsetown, which evidently has, in large part, no marine 
representatives upon the eastern border of the Cordilleran 
continent. The Dakota group, which is the equivalent to 
at least a portion of the Horsetown, is either absent or is a 
non-marine, plant-bearing series, but which, moreover, in 
any case is omitted from any part of the comparison. 


Accordingly, almost the whole class of cephalopods listed 
in his scheme have neither complementary elements nor 
even contemporaries in the Comanche series. The con- 
trast is therefore evidently less than it would appear to 
be; but in so far as it is strictly applicable, it is quite 

On the other hand, as has been already shown, when 
the fauna of the Colorado group is compared to that of the 
Chico, particularly as represented in the basin of Southern 
Oregon, a strong resemblance is apparent, and there is 
promise of a still closer relationship being recognized when 
the fauna has become better known. In the paper by Hill 
already referred to, the Dakota beds are given a position 
equivalent to the Cenomanian, and the facts made use of in 
the present paper are entirely in accord with that correla- 
tion. It appears, therefore, that the hiatus which has been 
here described as existing between the Knoxville (Pas- 
kenta) and the Chico beds over so large a part of the 
Coast Range region of the West, has its parallel and con- 
temporary phenomenon in the deposits of the interior; and 
the subsidence that followed the lateral extension of land 
conditions on both sides of the Cordilleran continent, was, 
therefore, epeirogenic; that is, it was synchronous on both 
borders of that continent. 

4. Equivalents of the Knoxville. 

The earlier Cretaceous deposits of the Pacific border and 
of Texas are more or less indirectly correlated, since there 
is little or no faunal resemblance between them, and they 
are too remote from each other to warrant a lithological 
comparison. Still, it is not amiss to recall the facts that 
the most calcareous portions of the California Cretaceous 
are those of the true Knoxville (or Paskenta) strata, which 
are often not unlike the Hmestones of the Comanche. It 
is these horizons between which Mr. Stanton (1897, p. 608) 
has pointed out such striking faunal contrasts, but of which 
he says: "The two faunas are complements of each 


Other, and both must be taken together to make up a really- 
representative Lower Cretaceous fauna." Of their syn- 
chrony he apparently has no doubt. 

In his summary of the deposits of San Luis Potosi, 
Mexico (Stanton, 1895, p. 26), he recognizes therein 
equivalents not only of the Knoxville, but apparently also 
of the Upper Cretaceous, possibly of the Horsetown ; 
while below these is the lower division of group No. 2, 
which he refers to the Jurassic. It shows a general resem- 
blance to the fauna of the Mariposa beds in the large num- 
ber of species of Perisphinctes, and in the presence of 
Olcostephanus, Belemnttes, and Aucella. 

The equivalents of the lowest portion of the Sacramento 
section have not yet been clearly recognized. As to 
whether the group which has been termed the Sub-Knox- 
ville should really be classed with the Cretaceous or with 
the Jurassic, there has been a difference of opinion. C. A. 
White was convinced that but a single species of Aucella 
was known from the Knoxville and from the Mariposa 
beds; and the separation of these groups was not deter- 
mined by a distinction of the species of this doubtful genus. 
J. P. Smith (1895, p. 381) has expressed views strongly 
favoring the Jurassic determination not only of the Sub- 
Knoxville fauna with Aucella fiochi, but he also points 
out the very close relationship between certain members of 
the Knoxville fauna and the Volga stage of Russia. Quite 
similarly, the lowest beds of the Queen Charlotte Islands 
section, a portion of "Division C" of J. F. Whiteaves 
(1876-84), has been compared to the same horizon of Russia. 
The Knoxville horizon, as here restricted, has not been 
shown to occur either upon the Queen Charlotte Islands 
or upon the mainland of British Columbia. The relation- 
ship between these beds and the Russian deposits appears 
most strongly in some of the ammonites, which have not 
been found-in any of the Californian beds. If this obser- 
vation proves to be trustworthy, then the Sub-Knoxville of 
the Sacramento basin is perhaps the equivalent of the low- 
est member of the Queen Charlotte Islands group, or of 


"Division C," and both may be compared to the Volga 
stage and similar deposits. 

Among the authors whose opinions are of more than 
ordinary weight upon this topic may be mentioned the name 
of Emil Haug (1898, p. 226). While conceding the Neoco- 
mian equivalency of the upper portion of the Knoxville 
(evidently the Paskenta), he plainly states that the lower por- 
tion of the "Knoxville beds" undoubtedly corresponds to 
the upper Portlandian of the Mediterranean region, which 
he correlates with the upper Volgian, the Tithonian and 
the Purbeck beds, and to the same horizon he refers the 
Jurassic portion of the series found at Catorce in the State 
of San Luis Potosi, Mexico. This seems to be on the 
whole the most satisfactory correlation of these beds yet 


The subsidence recognized independently for the regions 
of Texas and California was synchronous throughout the 
Cordilleras. It culminated with the close of the Comanche- 
Knoxville epoch, attaining, probably, as great a depression 
in these regions during the Cretaceous period as has since 
been reached. The sea extended over western Texas and 
eastern Mexico nearly, if not quite, to meet the waters of 
the Pacific, which covered western Mexico. 

Following this period of depression was an epeirogenic 
uplift of the Cordilleran continent, which threw the 
shore-lines seaward upon both of its borders and thus cor- 
respondingly expanded the terrestrial areas, and excluded 
accordingly from the territory thus added to the continental 
margins the contemporaneous deposits of the Dakota and 
the Horsetown groups. 

Following the upHft of the Cordilleras were the disturb- 
ances that resulted in the contemporaneous overlaps of the 
Chico and of the Colorado, and the continued subsidence 
of the remon until marine communications were estabHshed 
between the interior basin and the Pacific Ocean, which 
enabled species to pass from one to the other unobstructed. 


The return of the sea upon the continental borders resulted 
in the deposition of Cenomanian equivalents upon the older 
Cretaceous deposits unconformably, as is seen on the one 
hand, between the Knoxville and the Chico, and on the 
other, between the Comanche and the Colorado. 

How widely spread this unconformable relation may 
appear to be remains to be discovered, but judging from 
the almost continuous series of the Cretaceous deposits in 
favorable localities, it can hardly be expected that uncon- 
formities will always be found where Comanche and Colo- 
rado rocks are present. The double character of the 
Chico group reminds one alike of the Trichinopoly and 
Arrialoor of the Indian Cretaceous, of the later subdivi- 
sions of the Rock}^ Mountain section, and of the Turonian 
and Senonian overlap upon the European continent. It 
therefore appears that disturbances of a similar character 
occurred in very remote regions during the closing epochs 
of the Cretaceous period. 

VIII. Summary and Conxlusions. 

The foregoing discussion of the Cretaceous deposits of 
the Pacific border is designed to contain a statement of our 
present knowledge of the subject, and particularly of the 
Cretaceous deposits of California and Oregon. An at- 
tempt has been made to revive the earlier views regarding 
the complexity of the series, which have been to a con- 
siderable extent suppressed. The view more recently 
maintained, that the series is one of comparative simplicity, 
even in its most complete developments, has proved to be 
misleading when applied to districts outside of a rather 
restricted basin. The series at its best cannot be called 
simple, its continuity having been frequently disturbed 
even when deposition was most uniform in the basin of 
the Great Valley. While the disturbances have not always 
been sufficiently great to destroy all existing marine species, 
and thus obliterate faunal connections between deposits of 
succeeding epochs, yet it is evident that only the most 


persistent forms have survived from one epoch to the next. 
The faunal evidence of such disturbances is reinforced by 
the abundance of conglomerates which are interstratified 
with sandy and shaly beds, especially in the upper portion 
of the series. Coincident with the evidence of these facts 
is that of the territorial distribution of different members 
of the series in California and Oregon. 

The Cretaceous series of the Sacramento basin and of 
the whole Pacific border (excluding the Sub-Knoxville, 
which is probably of pre-Cretaceous age), is divisible into 
the following well defined members: (i) The Knoxville 
horizon, including several thousand feet of strata extending 
upward to the upper limit of the present known species of 
Aucella, embracing what has been shown to be essentially 
a boreal fauna; (2) the Horsetown horizon, beginning 
with the close of the Knoxville and the substitution of a 
typical subtropical fauna for one of boreal character, and 
continuing to the horizon representing the great Chico 
overlap; (3) the Chico, or uppermost member of the 
series, as represented in the Phoenix beds and the beds of 
Wallala, Silverado Canon, Point Loma, and Todos Santos 
Bay, Lower California. 

The fauna of the Chico is characterized in its later por- 
tions by a large development of gasteropods and lamelli- 
branchs. It is divisible into two horizons, at least in the 
Sacramento basin, and perhaps elsewhere. The move- 
ments that have affected the region are to be inferred from 
the relations thus recognized. Their general order, par- 
ticularly in the basin of the Great Valley, has been down- 
ward from the first, but not continuously so. With the 
close of the Knoxville epoch, an interval of epeirogenic 
uplift prevailed, which withdrew a large amount of terri- 
tory from oceanic submergence, but which in favored 
places may have caused only a cessation of deposition, as 
in the Great Valley basin. The extent of this disturbance, 
and the duration of the interval, may be inferred from the 
great faunal change which was introduced with the Horse- 
town epoch. This was the most important disturbance of 

(6) December 3, 1902. 


the period, and was accompanied by extensive intrusions 
of peridotite in the Coast Range region of California and 

Succeeding the post-Knoxville elevation, the next great 
movement was that inaugurating the Dakota and later 
Horsetown disturbances, which later were followed by the 
great overlaps, extending along the Pacific border of both 
North and South America, from the coast of Chile to 
British Columbia, and in the interior basin, carrying the 
Upper Cretaceous far northward along the flanks of the 
Cordilleras. It was therefore of an epeirogenic nature, 
extending in longitude as well as latitude over great inland 

The close of the Chico epoch is not yet sufficiently well 
understood for any final statements; but the faunal differ- 
ence between this epoch and that of the Martinez, as 
restricted by J. C. Merriam, shows a hiatus, probably be- 
tween the Chico and the Eocene deposits of the Pacific 

The different members of the Cretaceous series of Cali- 
fornia find their counterparts in other portions of the Pacific 
border, in British Columbia, Mexico and Chile, and are to 
be closely correlated with the recognized members of the 
interior basin deposits, with those of Asia and of Europe. 
This is shown not only by the parallelism of their develop- 
ments, but also by their faunal resemblances, amounting 
often to close specific affinities, and even specific identity. 

The crustal movements that have affected the Pacific 
border of America have been much more general than has 
been commonly believed. Simultaneous disturbances of 
the same tendency may be traced in many of the great 
Cretaceous series of the world. 


Part II. 

Description of Species. 

In the following descriptions of fossil species, it has been 
the endeavor, whenever possible, to recognize from previ- 
ously published figures and descriptions the forms that have 
been found by others and listed as authentic species. 
There are among the collections of the University of Cali- 
fornia many type-specimens from which Gabb's original 
descriptions were made, and considerable other material 
which was labeled by Mr. Gabb and turned over by the 
State Survey to the State University. Such material has 
proved to be of great service in the identification of species 
described in the publications of the State Geological Sur- 
vey. Much kindly interest has been shown, and great 
assistance given in the preparation of this paper, by those 
chiefly interested in extending our knowledge of West 
Coast geology, and especially of Pacific Coast Cretaceous 

It is not improbable that when the Cretaceous fauna of 
California becomes better known many of the species that 
have been described as new will prove to be either identical 
with, or very closely allied to, Atlantic or to other Pacific 
forms. It is with this feeling that man}^ of the names are 
proposed in the present descriptions; but an identification 
of this kind will not be retarded by the attachment of mere 
names, while the published descriptions of these forms will, 
it is hoped, stimulate closer comparison. 

It is evident to any one familiar with the different types 
of the genera Lytoceras and Desmoceras that too much lax- 
ness has been allowed in the determination of species. 
Forms that have barely more than a general resemblance 
have been included under a common name. Note, for 
example, Desmoce?'as jtigalis, Desmoceras hoj'nianni, Lytoc- 
eras batesi, and many others. 



1. Rhynchonella densleonis, sp. no v. 

Plate VII, Figs. 157 and 158. 

Shell of medium size, attaining a diameter of 11-12 mm.; trigonal; gib- 
bous; when full grown, the greatest convexity being near the middle; poste- 
rior lateral margins straight, sloping from the beak at an angle of about 
90 degrees; anterior margin somewhat broadly rounded; dorsal valve more 
convex than the ventral, nearly globose; ventral valve flattened, though 
bearing a deep sinus; anterior half of each valve bearing strong, rounded or 
angular plications which disappear on the posterior portion of the shell; sur- 
face of both valves bearing fine striations most plainly seen on the posterior 
half of the shell. The sinus of the ventral valve bears three or four plica- 
tions, while the corresponding prominence on the dorsal valve bears four or 
more; beak not very prominent and only slightly curved; deltidium small; 
width of shell greater than length. 

This species seems to be very closely related to Rhyn- 
chonella gnathofhora Meek.^ Whiteaves states that R. 
matidensis Whiteaves^ also resembles Meek's species, and 
it is therefore not unlikely that the two Cretaceous species 
are identical. 

Occurrence. — This species is not uncommon at Horse- 
town, Shasta County, California, in the uppermost beds of 
this division. In this respect it may also agree with 
R. matidensts. 

2. Rhynchonella whiteana, sp. nov. 

Plate VII, Figs. 160 and 161. 

Associated with the former species is another somewhat related form, with 
a finer and more subdued sculpture. The ventral sinus bears about nine or 
ten plications of uniform size and none of the strong folds of the other. The 
shell is rather circular in outline. The dorsal valve is crossed by two diverg- 
ing ridges meeting on the anterior margin the borders of the ventral sinus. 

» Pal. Cat., Vol. I, p. 39, PI. VIII. 
* Mes. Foss., Vol. I, p. 252. 



3. Inoceramus adunca, sp. nov. 

Plate IX, Figs. 188 and 189. 

Shell equivalve or nearly so, narrowly oval; margin elliptical; anterior side 
short, rounded, sloping rapidly from the beaks; base forming a broad curve; 
posterior side longer than high, meeting the basal margin in a rounded point; 
beaks high, very prominent and full, forming a strongly curved hook; surface 
having moderately strong concentric ridges, not regularly disposed. 

Length of shell 5.8 cm.; height 3.15 cm.; thickness of each valve 2.25 cm. 

This shell recalls by its strongly curved beaks some of 
the species of the Colorado group of the Upper Missouri 

Occurrence. — A single specimen of this shell was found 
at the Forty-nine Mine, near Phoenix, Oregon, associated 
with species of Schlcenhachia, Scaphttes, Lytoceras, and 
Desmoceras. It apparently belongs to the horizon of the 
Lower Chico. 

4. Inoceramus klamathensis, sp. nov. 
Plate IX, Figs. 185 and 186. 

Shell small, not attaining a size much above that shown in the figures, in- 
equivalve, the left valve being much more strongly arched, the right being 
somewhat flattened, or compressed; left valve showing a tendency to form 
an umbonal angle and depression at mature age; hinge line short, and form- 
ing an angle of 60 degrees with the anterior margin. 

In the largest specimen found the length of the shell from the point of the 
long, narrow beak to the extreme border is about 40 nim., width 25 mm.; 
curvature of the left valve about 15 mm. 

Occurrence. — This species was found in the Lower Chico 
beds of Willow Creek, Siskiyou County, California, and 
at the Forty-nine Mine in Southern Oregon. 

5. Pholadomya anaana, sp. nov. 

Plate VII, Fig. 151. 

Shell gibbous, oval, rounded on the anterior and lower margins, narrowing 
rapidly behind; beaks subcentral, but a little in advance of the middle, high 


and incurved; surface marked with fine, regular, concentric lines; radiating 
ridges, usually six in number, crossing the posterior surface, the last and 
heaviest one followed by a groove extending from the beak to the margin; 
hinge not distinct. 

Length of shell, 2.5 cm. or more; height, 2 cm.; thickness, 1.6 cm. 

Occurrence. — The species is known from five or six 
specimens obtained by Dr. Fairbanks from the Santiago 
and the Silverado canyons of the Santa Ana range in 
Orange County, CaHfornia. It was associated with Pcc- 
ttmctilus -pacijictis, Schlanbachia gahhi, and other species 
known only in the Lower Chico. The same, or a very 
similar species, is reported by Dr. Smith from the Lower 
Chico of the San Fernando Mountains, Los Angeles 
County, California. 

6. Pectunculus pacificus, sp. nov. 
Plate VII, Fig. 159. 

cf. Pectunculus subplanatus Stol., Pal. Ind., Vol. Ill, p. 347, Pis. XVII 
and XLIX. 
Shell subcircular, compressed; beaks central, low, sometimes a little prom- 
inent; surface nearly smooth, yet marked with fine radiating strite and a few 
faint lines of growth; thickness of shell two-thirds the vertical diameter; 
hinge-margin angularly truncated in some specimens, both anteriorly and 
posteriorly; diameter generally 1.5 to 3 cm. 

Occurrence. — The type of this species was obtained by 
H. W. Fairbanks from the Santiago Canyon of Orange 
County, California, where it is associated with Schlccnbachia 
gabbi, Baculites, fairbanksi, and other species that are 
known only from the lower portion of the Chico. It occurs 
also in the lower Chico beds of Southern Oregon, at the 
Forty-nine Mine, and the Smith ranch. 

The type of this species is the property of Dr. H. W. 
Fairbanks, Berkeley, California. 

7. Mactra gabbiana, sp. nov. 
Plate VII, Fig. 156. 

Shell moderate in size, somewhat resembling M. ashburneri Gabb, but 
generally with a heavier shell, and more strongly grooved concentrically; 
umbonal angle strongly marked, especially near the base; anterior surface 
flattened but not excavated. 


Gabb appears to have seen this species in the Chico beds 
of California, but did not distinguish it from M. ashburneri 

Occurrence. — This species occurs in the Lower Chico 
beds of Henley and Willow Creek, in Siskiyou County, 
and in the Santa Ana and Temescal mountains of Los 
Angeles and Riverside counties, in California. 


8. Haliotis lomaensis, sp. nov. 

Pl.\te IX, Fig. 183. 

Shell small, length 1.3 cm., oval, the two lateral margins nearly equally 
curved; convex, the back angled at the row of perforations; spire low, indis- 
tinct, not terminal; lips continuous around the spire end, expanded along 
both sides, forming a thin margin; muscle-impression central, oval, slightly 
roughened; perforations four, preceded by a slight marginal notch, and pro- 
duced ridge behind; surface marked by concentric lines extending around 
the entire body-whorl near the margin; radial lines also seen; convexity of 
shell about one-fourth the length ; width five-sixths the length. 

This shell appears to resemble in many respects Tryon's 
group of H. iris. 

Occurrence, — The type of this interesting species, which 
is in the collections of the State Mining Bureau, San Fran- 
cisco, was obtained by H. W. Fairbanks from the Lower 
Chico of San Diego County, California. A single speci- 
men was found in the beds at Point Loma, associated with 
Pecten californicus, Actceonina pic^oides, and Upper Chico 
forms; but below the beds contain Coralliochama orcutti, 
according to the statements of Dr. Fairbanks. It is doubt- 
less the oldest Haliotis known, being somewhat lower in 
position than the //. antiqua Bink. of the Maestricht beds. 

9. Erato veraghoorensis (?) Stol. 
Plate IX, Figs. iSi and 182. 

Erato (?) veraghoorensis Stol., Paleont. Ind., Vol. II, p. 59, PI. IV, fig. 
14, etc. 
Shell ovate, more inflated posteriorly; spire low though distinct, about 
one-eighth of the entire length of the shell; outer lips thickened and reflexed, 


broadly rounded, denticulate with fine ridges on the inner margin; aperture 
narrow, somewhat S-shaped, a little wider at anterior end; shell notched both 
before and behind; inner lip rounded, not known to be toothed; surface 
smooth and polished. The outer lip is slightly expanded posteriorly in an 
ear-like elevation that rises to a level with the low spire. The anterior end 
of the inner lip is bent a little downward just before reaching the forward 
notch. Both notches are somewhat shallow, the posterior one showing an 
upward curve or groove between the spire and the ear-like expansion of the 
outer lip. 

Occurrence. — One good specimen of this shell was found 

at the Smith ranch, Oregon. 

10. Gyrodes siskiyouensis, sp. nov. 
Plate VIII, Figs. 167 and 168. 

Shell moderate in size, subglobose, though a little compressed, spire low; 
upper surface a little flattened near the suture, forming a narrow ledge and 
angle; the whole surface plainly marked by revolving lines, most developed 
near the angle above; umbilicus open and slightly angled; no lines of growth 
visible, except on perfectly preserved shells. 

Occurrence. — This shell is common on the north slope of 
the Siskiyou Mountains, in the Chico beds. It occurs 
with Dcsmoceras ashlandicum, and CuciiUcea truncata, and 
many other gasteropods and bivalves that belong to the 

II. Anchura condoniana, sp. nov. 

Pl.\te \III, Fig. 179. 

Shell large, robust, with high spire; whorls about eight in number, moder- 
ately rounded; surface of spire ornamented by twenty or more longitudinal 
ridges; body-whorl entirely covered by longitudinal and revolving ridges 
equally developed; lip long and falcate, extending laterally, but bearing a 
spur-like process near the spire; lip strongly angled along the back, with 
angle extending upon the body-whorl; lip also bearing an angle on its outer 

Occurrence. — This species was found in the Lower Chico 
beds of the Forty-nine Mine, near Phoenix, Oregon, asso- 
ciated with many species of Schlcenbackia and Scaf kites. 



12. Nautilus gabbi, sp. no v. 

Nautilus texanus (?) (Shum.) Gabb, Pal. Cal., Vol. I, p. 59, PI. IX. 

There is in N. gabbi about the same number of septa that Stoliczka states 
commonly occurs with A^. kayeaniis; the umbilicus is similarly small, though 
not closed, the position of the siphuncle is subcentral, a little nearer the base 
of the septa, and the ornamentation of the shell is the same in so far as the 
flexuous radial markings are concerned. There is the same backward curve 
upon the ventral surface. Small specimens of the Shasta species show in 
addition to this some fine revolving striae that give a beautiful cross-hatched 
sculpture that is not seen in any of the older specimens. 

This species of A^autilus,\Y\nch. Gabb doubtfully referred 
to the Texan species, has recently been collected upon Cot- 
tonwood Creek, by Dr. J. P. Smith. It agrees in all respects 
with Gabb's figures, and it seems probable that it was from 
one of the specimens obtained from Shasta County that the 
figures were made. Gabb reports the species also from 
Mount Diablo, but the identity of the two species ought to 
be accepted with hesitation. It resembles in some respects 
JV. campbellt Meek from Comox, Vancouver Island, and 
might be mistaken for this species. 

Nautilus gabbi \% closely related to N. kayeaniis Stol. from 
the Ootatoor beds of Southern India. Stoliczka considers 
his species a representative of a group of associated forms, 
one of which he identifies with N. fscudo-clegans d'Orbigny. 

Occurrence. — Nautilus gabbi is found in the Upper 
Horsetown beds of Shasta Count}', California, though its 
range has not yet been ascertained. 

Two specimens of a Nautilus labeled " Claytons, Contra 
Costa County" are among the Pioche collection at the 
University of California. They apparently belong to a 
distinct species, in which the umbilicus is entirely covered 
by a thick callous, and which has a characteristic ornamen- 
tation of surface. The dark coloration is preserved upon 


the portion covered by the body-whorl in one of the speci- 
mens, and the outermost layer is marked by minute granu- 
lations that have a systematic arrangement in rows parallel 
to the median plane. 

13. Nautilus charlottensis Whitcaves. 

Nautiltts sttciaensisyNH\TK\\'Ti.s, Mes. Foss., Vol. I, 1876-84, p. 197, PI. XXI. 
Nautilus charlottensis Whitcaves, Mes. Foss., Vol. I, p. 269. 

A fine example of this species was found at Horsetown, 
Shasta County, California; it is in the museum of Stanford 
University. Whiteaves reports it from the Upper Creta- 
ceous of the Queen Charlotte Islands. In the Horsetown 
examples the siphonal tube is perhaps a little lower in its 
position than in the northern specimens. It appears to be 
very similar to JV. pseudo-clegans d'Orbigny,' although the 
position of the siphonal tube is a little higher than in 
d'Orbigny's figure. There is a relationship between N. 
gabhi and ^V. charlottensis, similar Indian species mentioned 
in the preceding description. 

14. Nautilus sp. 

Among the collections obtained by Dr. Bowers from the 
Santa Ana Mountains are two imperfect specimens of 
NaiitiliLS that appear to be related to N. gabhi and N. char- 
lottensis, though not identical with either. It forms, perhaps, 
a third member of this group belonging to the Pacific border 

15. Placenticeras californicum, sp. nov. 

Plate VIII, Figs. 173-177. 

The shell is discoidal, compressed, narrowing regularly from the umbilical 
region outward; inclined to be rough or with coarse ribs; costee flexuous, 
extending to the umbilicus, and terminating outward in tubercles upon the 

1 Pal. Franc. Terr. Cret., Vol. I, Pis. IX and XIX. 


peripheral angle; tubercles elongated and narrow, standing in single rows on 
either side of the ventral surface, and opposite one another. The ribs are 
low and rounded, and about equal in width to the intervening furrows. On 
old shells they reach the number of about forty on an entire whorl, while on 
younger shells the number is generally less. The ribs incline strongly for- 
ward on leaving the umbilicus, but about the middle of the shell describe a 
sharp curve backward, followed by a more gentle forward curve on approach- 
ing the marginal tubercles. Upon the periphery the space between the rows 
of tubercles is flattened and band-like, being equal in width to one-third the 
thickness of the shell. The early stages of this shell have been described by 
Dr. J. P. Smith, ^ and its relations to the next species stated. 

Hitherto the genus Placcnticeras has been but little known 
in the Cretaceous of the Pacific border. Two allied species 
have recently been recognized in the Lower Chico beds in 
widely separated districts in California and Oregon. In 
the above named species the shell is of moderate size, the 
largest specimen having the following dimensions: — 

Diameter 120 mm. 

Height of last coil 58 mm. 

Width of last coil 30 . 5 mm. 

Width of umbilicus 23 mm. 

Involution 13 mm. 

Occurrence. — This shell is known from the Lower Chico 
of Phoenix, Henley, Arroyo del Valle, and the San Fernando 

The type is in the collections of the University of 

16. Placcnticeras pacificum Smith. 

Plate VIII, Figs. 162-164 and 171-172; Plate IX, Fig. 180. 

Placeiiticer as pacific iivi Smith, Proc. Cal. Acad. Sci., 3d Ser., Geol., Vol. I, 
pp. 207-210, Pis. XXV-XXVIII. 

Shell discoidal, involute, compressed, and moderately smooth; size of 
largest shell about 16.5 cm. in greatest diameter. The species is related to 
the preceding and superficially differs from it chiefly in being smoother and 
more graceful in its ornamentation. As shown in the figures and description 
(1. c), in its younger stages it is characterized by its smooth form, without 
ribs or tubercles. The development of the two species is entirely different. 

1 Proc. Cal. Acad. Sci., 3d Set. Geol., Vol. I, p. 181. 


Occurrence. — The species occurs with the preceding at 
Phoenix, Henley, and Arroyo del Valle, and Dr. Smith 
states that he has found it in the Lower Chico beds of the 
Silverado Canyon, Orange County, California. 

17. Phylloceras shastalense, sp. nov. 

Plate IV, Figs. 112-115. 

Shell small, inflated, not globose, rapidly increasing in width; section of 
body-whorl nearly circular, but in younger stages elliptical; umbilicus closed, 
or not showing any of the earlier whorls, except in minute specimens; surface 
crossed by transverse ribs that are tolerably coarse compared with those of 
other species lower in the series. The ribs begin at the umbilical depression 
and run transversely over the ventral surface, making only slight curves. 
The diameter of the largest specimen found is 3 cm., from which most of the 
body-chamber is missing. The suture is clearly that of a Phylloceras. It 
does not appear to be closely related to either of the previously known forms 
of this genus from the Pacific Coast. It is more nearly allied to Ammonites 
rouyanus d'Orbigny'^ though less flattened ventrally than this species, as 
represented in the figure. 

Occurrence. — This species is quite common at Ilorsetown, 
Shasta County, California, where four or five good speci- 
rhens were recently collected. 

The type is in the collection of the University of 

18. Schliiteria diabloensis, sp. nov. 
Plate III, Figs. 105-106. 

Among the ammonites labeled by Gabb ^^Am. jugalis'' 
is an undescribed species of Schliiteria for which the name 
S . diabloensis is here proposed. 

The greatest diameter of the largest specimen is 2.5 cm., with a thickness 
near the umbilicus of 1.2 cm. The umbilicus is small, with sides that become 
very abrupt at this diameter, though the younger portion of the shell shows 
more gentle slopes. The sides are apparently smooth or marked with a few 
faint transverse grooves, and are flattened and gently converge outward. 
The fine lines of growth curve a little backward after crossing the umbilical 
shoulder. The suture is that of a Desmoceras, though in shape and gen- 
eral appearance the species might be considered a Phylloceras. 

spal. Franc. Terr. Cret., Vol. I, PI. CX, figs. 3-5. 


Occurrence. — The specimen from which the figures have 
been drawn is labeled " Mt. Diablo," and being in a collec- 
tion with several others of the same species from Curry's 
is probably also from that locality. Other species from this 
locality, as stated elsewhere, show a low horizon of the 

The type is in the collection of the University of California. 

19. Lytoceras rel. duvalianum d'Orh. 

Plate VI, Figs. 140-143. 

Ammonites duvalianus d'Orb., Pal. Franc. Terr., Vol. I, PI. L. 

Among the close allies to European forms found in the 
Cretaceous of the Pacific Coast, there are few that seem 
more truly identical than this one. If d'Orbigny's figure 
represents the suture of this species correctly, both lobes 
and saddles are relatively narrower in the California types, 
otherwise there is but little difference, unless it is in the 
less equal division of the lobes. The form of the shell 
and its surface markings are too nearly like d'Orbigny's 
species to justify any other name being applied at present. 
There are certainly greater ranges of variation recognized 
in nearly all Cahfornian types than there appear to be 
between the specimens from California and the European 
form as figured by d'Orbigny. 

In the young shell from the Shasta beds the constrictions are scarcely 
noticeable but begin to appear upon the sides, without crossing the ventral 
surface, at a diameter of 3 cm. They reach their clearest development at 4 
or 5 cm., and then again diminish. At first they form upon the sides only 
broad, undulatory ridges, between which the constrictions become more 
sharply defined with growth, becoming deeper upon their posterior margin 
and diminishing in depth forward. Between the constrictions, which are 
about twenty in number, the surface is covered by fine transverse lines, yet 
the shell has an almost polished appearance. The section of the whorl is 
quadrate in the adult but is more rounded upon the ventral side in youth. 
The walls of the umbilicus are abrupt, and the involution covers about one- 
half of the width of the whorl. 

Occurrence. — Two good specimens of this species, one 
of which is the type, were found near the mouth of Hulen 


Creek, and three were obtained at Horsetown, Shasta 
County, California. L.ytoceras duvaliamun d'Orbigny is 
found in the Neocomian of Europe. 

The types of this species are among the collections of 
the University of California. 

20. Lytoceras (Tetragonites) jacksonense, sp. nov. 

Plate V, Figs. 124-125. 

Shell moderately compressed, rounded, smooth; size of type 6.33 cm. in 
diameter; umbilicus rather narrow, walls steep, rounded on the shoulders; 
involution covering the larger part of the preceding coil; section subcircular, 
somewhat quadrate, slightly thicker near the umbilical shoulder, from whic^i 
zone the sides slope gently toward the periphery. Faint grooves are to be 
seen obliquely crossing the sides and inclining forward, and forming upon 
the ventral surface a wide, backward curve, very much as is seen in the next 
species, to which this one is somewhat related. Faint lines of growth are 
barely perceptible upon the portions of test yet remaining, which are parallel 
to the grooves. The suture consists of four or five very much divided sad- 
dles, narrow, and unequally bifid, the outer branch of which is the smaller. 
The lobes are relatively wider, with branches terminating in pointed denti- 
cles. The division of the lobes is more equally bifid than that of the sad- 
dles. Both lobes and saddles diminish uniformly in size from the e.xternal 
side inward to the umbilicus. The small siphonal saddle is narrow and 

Occurrence. — A single specimen of this shell was ob- 
tained from the Forty-nine Mine, near Phoenix, Oregon. 
The locality has been referred to the Lower Chico beds in 
the body of this paper. 

The type of the species is in the California Academy of 

21. Lytoceras (Gaudryceras) sacya Forbes. 

Ammonites sacya Forbes, Trans. Geol. Soc. Lond., Ser. II, Vol. VII, 

1845-56, p. 113. 
Ammonites sacya (Forbes) Stol., Pal. Ind., Vol. I, p. 154, PI. LXXV. 
Ammo7iites whitfieyi 0\v.^, Pal. Cal., Vol. II, p. 134, PI. XXII, 1869. 
Lytoceras sacya Whiteaves, Mes. Foss., Vol. I, 1876-84, Pt. I, p. 43, etc. 
Lytoceras (Gaudryceras) sacya Whiteaves, Mes. Foss., Vol. I, 1876-84, 

Pt. IV, p. 270. 

In the upper portion of the Horse*town beds this species 
is fairly abundant and generally takes the place of 


Lytoceras baiesi, occurring lower in the series. Aiinjwnitcs 
whitneyi has not yet been clearly recognized as a distinct 
species, and to any one familiar with the fauna of this hori- 
zon there can hardly be a doubt that Gabb's species and 
Lytoceras sacya are the same. Gabb's figure is apparently 
defective, showing too deep and too early constrictions on 
the shell. On older specimens of Lytoceras sacya these 
appear to be constant, but are lacking on shells below a 
diameter of 6.33 centimeters. 

Occurrence. — Lytoceras sacya occurs in the Upper Horse- 
town beds of California, and the Lower Chico beds of 
California and Oregon, and in beds equivalent to the 
Upper Horsetown on Queen Charlotte Islands. 

22. Lytoceras (Gaudryceras) kayei Forbes. 

Ammonites kayei Forbes, Trans. Geol. Soc. Lond., Ser. II, Vol. VII, 

1845-56, p. lOI. 
Ammonites tiayei (?) (Forbes) Stol., Pal. Ind., Vol. I, p. 156, PI. LXXVII, 

fig. I. 
Lytoceras tiayei Forbes, Stein., Jahrb. f. Min., etc., Bell.-Bd. X, 1895-96, 

p. 86. 

Shell discoidal, thin, increasing very slowly in diameter; section of the 
whorls transversely elliptical; umbilicus wide and shallow, coils small, orna- 
mentation simple, surface crossed by oblique lines and a few moderately 
deep grooves. Septation well represented by Steinman's figure (1. c, p. 87). 

There are few more interesting discoveries here noted 
than the identification of this characteristic Upper Creta- 
ceous species from the Chico beds of California. The 
shell in all of its details of ornamentation and sutures is 
almost the exact facsimile of the species from the west 
coast of Chile and from the Pondicherri District of Southern 
India, as well as can be judged from the figures. 

Occurrence. — A single well preserved specimen from 
Mount Diablo is in the collections of the University of 


23. Lytoceras (Tetragonites) cala (?) (Forbes) StoUczka. 

cf. Ammonites cala Forbes, Trans. Geol. Soc. Lond., Ser. II, Vol. VII, 

1845-56, p. 204. 
Ammonites cala (?) (Forbes) Stol., Pal. Ind., Vol. I, p. 153, PI. LXXV. 

In the collections of Lorenzo G. Yates, temporarily^ 
deposited at Stanford University, are several specimens of 
a Lytoceras of the genus Tetragonites, which appear to be 
referable to L. cala, as described by Stoliczka. They 
have been compared with both Forbes' and Stoliczka's 
figures, but so far as can be ascertained by this means they 
agree more nearly with the latter. They are from the 
Arroyo del Valle, eight miles southeast of Livermore, Ala- 
meda County, California. 

In all respects they agree perfectly with Stoliczka's 
description. The shell is evidently a close relative of 
Forbes' species, which could be distinguished from it onl}^ 
by a comparison of types. 

Shell discoidal, flattened on the sides, and of a diameter not exceeding 
7.6 cm.; umbilicus wide and shallow, with abrupt walls; involution very little, 
clasping little more than the flattened ventral surface; shell increasing slowly 
in size with growth; section of whorls tetragonal; suture consists of three 
lobes on each side, with auxiliary lobes much reduced, upon the umbilical 
surface. The siphonal lobe is broad, divided by a denticulated tongue- 
shaped siphonal saddle. 

Occurrence. — There are in the Yates collection four or 
five specimens of this shell, all of which have been obtained 
from the Jordan ranch on the Arroyo del Valle, eight miles 
southeast of Livermore, Alameda County, California. The 
horizon is that of the Lower Chico. Stoliczka says L. cala 
is from the Ootatoor beds of India. 

24. Lytoceras bates! (Trask) Gahh. 

Under the specific title of Ammonites hatesi Gabb included 
three quite clearly marked species which he recognized as 
only varieties. In all the larger collections of Cretaceous 
fossils in California there are numerous specimens of 
related forms bearing this name. The confusion is the 


result of Gabb's failure to recognize the true differences 
in these forms. The various representatives of the species, 
as understood by Gabb, for the most part may be easily 
separated into this and the two following types : Lytoceras 
batesi Trask (s. s.), Proc. Cal. Acad. Sci., Vol. I (2d Ed.) 
1855, p. 39; Pal. Cal., Vol. I, p. 67, pars., PI. XIII. 

The most striking difference between this species and the 
next one is in the rate at which they increase in diameter 
with growth. In Trask's original type this increase was 
relatively slow. According to his description, at a diameter 
of 14 cm. the width of the aperture measured 3 cm. Gabb's 
figure^ was probably drawn from Trask's type specimen. 
According to Trask, the section of the whorl is about cir- 
cular ("convolutions nearly round "). Both these charac- 
teristics were overlooked by Gabb, who included with it two 
species very different in both these respects. 

Occurrence. — It is not easy to decide the exact range of 
this species from the statements of Gabb. Evidently, 
though, it is found well toward the bottom of the Horse- 
town, and seems to have a wide stratigraphical range. 

25. Lytoceras argonautarum, sp. nov. 

Plate VII, Figs. 154-155. 

Ammonites batesi (pars.) Gabb, Pal. Cal., Vols. I and II, 1863. 

Shell discoidal, somewhat inflated, increasing rapidly in size; section of 
whorls not quite circular, flattened slightly on sides and ventrum; umbilicus 
deep, walls rapidly becoming steeper outwardly; involution slight, like that 
of the preceding species; suture similar to that of Lytoceras batesi, but cor- 
respondingly heavier and less regular; lateral lobes not equally bipartite, 
small siphonal saddle lanceolate, with minute denticulations; surface orna- 
mented with rounded, evenly spaced ridges, separated by wide, smooth, and 
shallow grooves, and in this respect unlike L. batesi. 

The type from which the figure was drawn was obtained 
by Dr. J. P. Smith, one and one-half miles east of Ono, 
Shasta County, California. Its greatest diameter is 17.1 cm., 

iPal. CaL, Vol. I, PL XIII. 

(7) December 10, 1902. 


while the corresponding width of the umbilicus is 5.7 cm. 
The specimen is the inner coil of a much larger shell, 
30 cm. in diameter. The aperture is not circular, but has 
a width of 8.4 cm,, and a depth of 7 cm. In this specimen 
the removal of one complete volution would reduce the 
diameter to 3.3 cm. Another specimen of the same spe- 
cies in the collections of the University of California, meas- 
uring a little over 40 cm. in diameter, would, by the removal 
of two complete volutions, be reduced to almost the same 
dimensions, 3.3 cm. The aperture of this gigantic speci- 
men measures 15 cm. in diameter. It does not contain the 
whole of the body-chamber, which would have consider- 
ably increased its diameter. This is evidently the species 
represented by the specimen to which Gabb has alluded^ 
as the "largest known species of California." It is not 
very difficult to recognize even the young shells of this 
species when compared with typical specimens of L. hatesi 
of the same diameter, or of the same number of coils. A 
specimen of this shell in the collections of the University of 
California measures sixteen inches in greatest diameter. 

Occu7'rence. — This species is found in the upper portion 
of the Horsetown, though its downward range is not known. 
Dr. Smith states that he has found what is probably the 
young of this species associated with Phylloceras ramostcm 
Meek and P. ono'ense Stanton in the Lower Chico beds of 
Arroyo del Valle, Alameda County, California. 

Lytoccras argonatitaj-tim, as Gabb has stated, is the 
largest ammonite known from the Cretaceous of California. 
The name is proposed in honor of the " argonauts " and 
gold-seekers of the pioneer days of California and the 
Pacific Coast. This gigantic cephalopod appropriately 
commemorates the motive and heroic spirit of these sturdy 
and brave adventurers who so often struggled with hard- 
ships even greater than those described in traditionary 

iPal. Cal., Vol. I, p. 67; Vol. II, p. 132. 


26. Lytoceras (Gabbioceras) angulatum, sp. nov. 

Plate VI, Fig. 139. 

Ammo7iites batesi (pars.) Gabb, Pal. Cal., Vol. II, p. 132, Pis. XX and XXI, 

figs. 9 and 10, 1863. 
Gabbioceras batesi Hyatt, Phylogeny of an Acquired Characteristic. 

One of the species which was believed by Gabb to be 
only a variety of Ammonites batesi has below the diameter 
of 3.8 cm. a strongly angular section. There are few who 
will maintain the identity of these species even upon an 
inspection of Gabb's figures. 

In the collections of the Universit}'' of California are three 
well preserved examples of this shell, from which the draw- 
ing (fig. 139) was made. One of the specimens has the 
aperture complete, though crushed. It has been restored 
in the figure. The shell does not apparently attain a large 
size. Two of the specimens seem to be mature and are 
less than three inches in diameter. 

The involution of the shell is considerably greater than 
either of the preceding species which Gabb included under 
the name Ammonites batesi. The body-chamber, which in 
these specimens occupies almost a complete whorl, is crossed 
superficially by a few moderately strong, transverse, sinuous 
grooves not evenly distributed. The shell between these is 
polished, though marked with a few fine lines which bend 
gently backward within the umbilicus. 

The shell increases rapidly in size after losing its angular 
character at a diameter of one inch or less. 

Occurrence. — The stratigraphical position of this species 
can not be given with certaint}'. The specimens are all 
labeled " Cottonwood Creek, Shasta County." They are 
probabl}" from the Horsetown beds of that region. 

27. Hamites ellipticus, sp. nov. 

Plate III, Figs. 102-103; Plate X, Fig. 191. 

Shell compressed, elliptical in section, more narrowly rounded upon the 
ventral or siphonal side than upon the dorsal; surface ornamented with sim- 
ple and narrow transverse ribs separated by wider, rounded grooves; no 


nodes or tubercles shown; suture line complex, consisting of six lobes and 
six saddles, each bifid, and showing the same tendency in all of the smaller 
divisions; both lobes and saddles widely branching, the former terminating 
in sharp denticular points, while the latter become more rounded in their 
terminations. The siphonal lobe is bipartite, with diverging branches, each 
of which is further divided, and above which is a smaller, secondary spur or 
branch. The antisiphonal lobe is more simple, consisting of an elongated 
and irregularly toothed neck, tripartite in its termination. The first lateral 
lobe is wider, though not quite so long as the second, and more regularly 
divided. The second lateral saddle is both broader and higher than the first 
one, and in its location occupies the middle of the rounded side. A single 
constriction is to be seen upon the fragment found, though it is not clear that 
this is not accidental. It consists of a broad and flattened depression (7.5 
mm. in width) upon the sides and ventral edge, which is not altogether regu- 
lar in its form. In front it is bordered by an oblique, rounded constriction 
one millimeter wide, against the posterior side of which terminate four or five 
of the preceding ribs. The succeeding ribs are thus set at an angle which 
places them not quite parallel with those preceding this broad depression of 
the sides. 

Occurrence. — Forty-nine Mine, near Phoenix, Oregon. 
The type is in the California Academy of Sciences. 

28. Hamites phoenixensis, sp. nov. 

Plate III, Fig. 104. 

Shell small, cylindrical in section, bent in one plane into a hook-like curve; 
surface ornamented with slightly oblique, transverse ribs inclining a little 
forward in passing from the inner to the ventral side of the whorl; ribs a 
little stronger on the ventral than upon the dorsal side, some rising consider- 
ably above the rest in approaching the ventral surface; whorls crossed at 
intervals by small rounded constrictions, not distinctly shown in the figure. 
The ribbing is not (juite regular in the vicinity of the reflex curve, and there 
seems to be a slight deviation from a true plane in this portion; and this seems 
to be still further indicated by the ribbing, which is not quite symmetrical at 
this point. 

The septation of this species is not known. In its form 
and sculpture, except for its lack of tubercular ornamenta- 
tion, it resembles Hamites royerianus d'Orbigny, which is 
said to come from the Neocomian of Europe; and in all 
respects except size it resembles H. cylindraceus, as figured 
by Whiteaves, from the Sucia Islands. It may be a small 
representative of this western species. 

Occurrence. — This species is from the Lower Chico beds 
of the Forty-nine Mine, near Phoenix, Oregon. 

The type is in the California Academy of Sciences. 


29. Hamites cylindraceus de France. 

Hamites cj/hidraceus {d'Orb.) de France, Pal. Franc, Vol. I, PI. CXXXVI. 
ScHLUTER, Paleontographica, Vol. XXI, p. 103, PI. XXXI. ? not //. cyl- 
indraceus (de France) Whiteaves, Canada Geol. Sur., Mes. Foss., 
Vol. I, 1876-S4, p. 113, PI. XIV. 

Among the fossil cephalopods collected in Southern 
Oregon is one that closely resembles //. cylindraceus, as 
figured by Schlliter (1. c), belonging to the Upper Creta- 
ceous of Europe. The suture line is not visible on any of 
the specimens collected, but in their superficial features 
they agree too nearly with the European species to justify 
any other determination. 

Shell not large, nearly cylindrical in section; elongated in the later portion, 
straightened and recurved into a hook-like bend with two parallel arms; sur- 
face crossed by simple annular ribs which are usually oblique to the axis, 
without nodes or noticeable irregularities, except in direction. Some of the 
ribs show a tendency to arrange themselves in planes perpendicular to the 
axis of the shell, but the inclination is generally forward on the siphonal side. 
The ribs are narrow and ridge-like, and separated by furrows which are 
rounded on the bottom and at least twice as wide as the ribs themselves. 
The diameter of the body-chamber in the largest specimen obtained is about 
1.7 centimeters. All the specimens lack the band-like constrictions seen on 
the species described by Whiteaves from the Sucia Islands. 

30. Hamites armatus, sp. nov. 

Plate V, Figs. 130-132. 

Shell of medium size, attaining a greater diameter of about 20 mm.; ellip- 
tical in cross-section; surface ornamented with regular rounded ribs inclining 
obliquely forward; body- whorl crossed by strong constrictions about 30 mm. 
apart, between which there are about twelve or thirteen parallel ribs; every 
fifth or sixth rib armed near the siphonal line with two widely diverging 
spines, attaining a length of 6 or 7 mm. ; the intervening ribs also armed but 
with shorter spines. The area between each pair of longer spines is some- 
what flattened, and marked by a narrow oval, especially when two of the 
ribs coalesce to form the spine-like tubercles. The septum of this extra- 
ordinary species is not yet known, but it is probably sufficiently well 

Occurrence. — This shell was found in the Lower Chico 
beds near Henley, Siskiyou County, California. It was 
found associated with Pachydiscus henleyensis, Desmoceras 


siigatiim^ Placenticeras californicitm, P. pacijicicm, and 
other Lower Chico forms. 

31. Hamites (Ptychoceras) aequicostatum Gabb. 

Ptychoceras cBquicostaticm Gabb, Pal. Cal., Vol. I, p. 74, PI. XIII, fig. 20; 
Vol. II, PI. XXV, figs. 20, e and /. '^o\. Helicancylus cequicostatus Gabb, 
Pal. Cal., Vol. II, p. 141, PI. XXV, figs. 20, a-d. 

Ptychoceras ceqtiicostatuni , as originally described by 
Gabb, is a true representative of this genus, and usually 
not difficult to recognize as such; it is not uncommon in 
the Upper Cretaceous beds of Shasta County. 

On the larger branch of the shell the transverse ribbing is rather heavy, 
and without ornamentation; the ribs themselves are high and narrow, the 
intervening spaces rather broad and concave. On the smaller branch the 
ribs are much less prominent, and the intervening spaces correspondingly 
shallow; many of the ribs, at least, are ornamented with lateral, mammillary 
tuf)ercles. Between tlie ribs which are so ornamented there are subordinate 
ridges that appear to be simple; and with these there are also subordinate 

These markings can be detected on Gabb's types and on 
other examples which are among the collections of the 
University of California. 

In Gabb's revised description of this species ' quite another 
genus (which Zittel refers to L.indigia, with some doubt) 
has been confused with this species, and both are placed in 
the genus Hclicancylus. 

32. Hamites (Ptychoceras) solanoense, sp. nov. 

Plate IX, Fig. 184. 

Shell of moderate size; smaller branch of the type 15.5 cm. in length, with 
an average diameter of 14 mm. ; tapering very gradually from small end to 
the recurved portion; surface marked by regular, simple, and rounded trans- 
verse ribs which are almost without ornamentation. There are seventy-five 
of these ribs on the whole length of the small branch, evenly distributed 
throughout. The only ornamentation noticed on these ribs are rows of very 
faint tubercules on the ventral surface, on either side of the median plane, 
most noticeable near the curve. On the dorsal side, which is somewhat 
flattened, the ribs are nearly suppressed. On the recurved portion they are 
also apparently less prominent. 

li'al. Cal., Vol. II, 1863, p. 141. See also Lindigia ? nodosum, this paper, page 92. 


Occurrence. — The type of this species is in the collection 
of the University of California. It was obtained from the 
Cretaceous beds near Vacaville, Solano County, California, 
by Mr. F. A. Steiger. 

33. Helicoceras indicum (?) Slol. 

Plate III, Figs. 96-97. 

cf. Helicoceras indicum Stol., Pal. Ind., Vol. I, p. 184, PI. LXXXVI. 

Shell small, coiled in a spiral, first to the right to a diameter of .7 cm. and 
then reversed; section of whorls at first nearly circular, but afterward ellipti- 
cal; surface marked by oblique transverse ridges not quite evenly spaced, 
also by three or four constrictions. Diameter of spiral, 2 cm. ; septation 

Occurrence. — A single specimen was obtained from the 
Smith ranch, two and one-half miles southwest of Phcenix, 
Oregon, and belongs to the horizon of the Lower Chico. 

The type here described is in the collection of the Cali- 
fornia Academy of Sciences. 

34. Heteroceras ceratopse, sp. nov. 

Plate III, Figs, ioo-ioi. 

Shell elliptical, or subcircular in section, very helicoid, forming widely open 
coils in mature age; coiled sometimes toward the right and sometimes toward 
the left, and therefore neither in one plane nor in a regular spiral; surface 
ornamented with numerous transverse striations intervening between much 
larger and elevated ridges that rise abruptly from the surface of the shell at 
intervals of a few millimeters. These ridge-like ribs begin upon the dorsal 
side in elevations hardly distinguishable from the intervening striations, and 
as they pass downward on the sides they become more and more elevated, 
until on the siphonal side they are often i mm. in height. They are rarely 
well enough preserved to show their exact character, but appear to be pointed 
or tuberculated along their thin blade-like summits. 

The average diameter of the specimens collected ranges from .5 cm. to 
I cm. The largest fragment has a length of 7 cm. All the fragments show 
a tendency to curve irregularly and to depart from a simple spiral. Tiie 
suture line is complex, consisting of bifid lobes and saddles; the lateral 
saddles show a tendency to tripartite division in their main branches, while 
the lobes retain their bipartite character throughout. In general form and 
ornamentation this species resembles very closely Heteroceras reussianuin 
d'Orbigny, as figured by Schliiter in " Paleontographia " (Vol. XXI, PI. 
XXXII), to which it may be related. 


Occurrence. — Found at the Smith ranch, east of Phoenix, 

Type in the CaHfornia Academy of Sciences. 

35. Lindigia ? nodosum, sp. nov. 

Helicancylus ccquicoslatiis Gabb, Pal, Cal., Vol. II, p. 141, PI. XXV, figs. 
20, a-g. 

Zittle refers this species doubtfully to the genus above 
given, which he has placed as a subgenus under Turrilites. 
Gabb figured the type of this species under the name Heli- 
cancylus. His description needs no special revision, except 
that the tuberculation is not sufficiently pronounced either 
in his figures or his description. On the larger coils of the 
spiral portion these tubercles are large and circular in 
section, or slightly elongated, and abruptly truncated at 
the top. 

Occurrence. — The type in the collection of the University 
of California is labeled, " Cottonwood Creek, Shasta 
County, California." 

36. Baculites fairbanksi, sp. nov. 

Plate VII, Figs. 152-153; Plate X, Fig. 194. 

cf. Baculites vagina Forbes, Trans. Geol. Soc. Lond., 2d Ser., Vol. VII, 

1845-56, p. 114. 
cf. Baculites vagina Forbes, in Stein., Neu. Jahrb. f. Min., etc., Beil.-Bd. X, 

1895-96, p. 89. 

The largest specimen is a fragment about 11. 5 cm. in length, and in largest 
diameter 1.5 cm. It is coarsely ribbed with strongly bent costa;, and shows 
distinct lines of growth. The section is ovate but does not show the narrow 
ridge along the siphonal edge as the figures of B. vagina appear to require. 
There is a depression a little below the middle of the side which may repre- 
sent it, however. There is a much closer resemblance found in the suture, 
which is composed of broad, bifid saddles and narrow lobes, also somewhat 
equally divided. The bifid or bipartite character is noticeable even in the 
smaller divisions of both lobes and saddles. 

This species is only distantly related to B. chico'cnsis 
Trask, but shows more affinity with the form described by 


Meek under that name; yet Meek's species is smooth while 
this one is costate, and there are some differences to be 
seen in the septation. Neither does it agree with the cos- 
tate variety of Gabb, which is that usually found near 

It appears remarkable that the widely distributed species 
of cephalopod, Baculites vagina, has not been recognized 
in the California Cretaceous deposits. It occurs both in 
Southern India and on the west coast of Chile, and ought 
to be found in the rich deposits of California, Oregon, and 
British Columbia. Perhaps the nearest approach to it is 
the above named species, brought from Orange County, 
California, by Dr. H. W. Fairbanks. There is certainly a 
very near relationship between the forms from Quiriquina 
Island and the Santa Ana Mountains of Orange County. 

Occurrence. — This species is found associated with many 
Lower Chico fossils near Silverado Canyon, in the Santa 
Ana Mountains of Orange County, California. It occurs 
along with Anchura calif ornica, Actmonella oviformis, 
Pholadomya anadna, and Chione varians. 


In the middle Cretaceous of California, forms of Desmoc- 
eras belonging to the group D. plamilatiini are numerous. 
Four or five types have been recognized that are capable of 
specific discrimination, some of them having ver}'^ strong 
resemblances to Atlantic forms, such as D. mayorianum 

Among the members of this group is Desmoceras hoff- 
manni Gabb.^ Gabb seems not to have recognized evident 
differences among them and accordingly classed all under 
one species, which does not appear to be justified. More 
than twenty fairly well preserved specimens of this group 
in the collections of Stanford University and the University 
of California may easily be divided into three subgroups. 
There can hardly be a doubt as to the distinctness of two 

1 Pal. Cal., Vol. I, PI. XI, not Vol. II, PI. XX. 


of these types, and probably the other is as deserving of 
recognition. All of them range in diameter below 12.7 cm., 
while some of them are considerably smaller, ranging down 
to the diameter of 2.5 cm. Some of the specimens in the 
collections of the University of California still retain the 
original labels attached to them by Gabb or other members 
of the State Geological Survey. 

The four succeeding types belong to the group 
D. -planu latu ni . 

37. Desmoceras hoffmanni Gabb} 

Plate V, Figs. 120-123; Plate X, Figure 203. 

It is not easy to determine which of the several forms of 
this group should bear the name proposed by Gabb. The 
species described in Vol. II of the Paleontology of Cali- 
fornia, and figured on Plate XX, which seems to belong to 
another type, has not been thus far identified. 

In the collections of the University of California are 
several specimens of a comparatively compressed shell, 
some of which bear the name D. hoffmanni, and appear to 
be referable to this species, except that the umbilicus is 
somewhat narrower. Gabb states that in D. hoffmanni the 
umbilicus has a diameter nearly equal to half that of the 
coil. The six specimens here referred to this species have 
a quite constant ratio between these measurements of 3.1:1, 
the umbilicus being measured just inside the angles, or 
shoulders. In the cross-section of the whorl they agree in 
the main with Gabb's figure," though some of them are 
relatively thicker. The number of constrictions does not 
exceed seven or eight, though they are not regularly 
disposed. The suture agrees in only a general way with 
Gabb's figure, which is evidently defective. His descrip- 
tion of the suture seems better, though it also is unsatisfac- 
tory. The suture line consists of a siphonal and several 

iNoTE. — This species has been selected by Alpheus Hyatt for the type of a new 
genus, Pleuropachydiscus of the family Silestidce (Eastman's Translation of Zittel's Paleon- 
tology), but there is no apparent reason for such a classification, and paleontologists 
who are most familiar with this species will probably accept it with hesitation. 

-'Pal. Cal., Vol. I, PI. II, figs. I3-I3a. 


lateral lobes, diminishing quite regularly in size from with- 
out inward. On whorls of a diameter of 10.2 cm. there are 
five of these lateral lobes which are unequally tripartite, so 
much so, in fact, that they might almost as appropriately be 
called unequally bipartite. The saddles are bifid, though 
they have not the terminations shown in Gabb's figure. 
Both lobes and saddles are moderately broad in their trunk 
portions, the lobes regularly so; the terminations of the 
lobes are digitiform, those of the saddles more or less 
broadly scolloped. The involution of the whorls is more 
than one-half and is, in one specimen, nearly two-thirds. 

Ocatrrence. — This species is found in abundance along 
Cottonwood Creek, Shasta County, California, in the upper 
portion of the Ilorsetown. It occurs also at Horsetown 

38. Desmoceras lecontei, sp. nov. 

Plate III, Figs. 94 and 95; Plate X, Fig. 190. 

Shell moderate in size, discoidal, flat, and rather involute; diameter of the 
largest specimen found, 8.5 cm.; greatest thickness, 2.75 cm.; ratio of the 
diameter of umbilicus to height of coil, 1:4; section of the whorl quadrate, 
narrowing slightly toward the periphery; umbilicus narrow, but not deep, the 
walls abrupt on each whorl, the inner coil forming a flattened ledge; ventral 
surface rounded or slightly flattened; sides and surface of shell ornamented 
with radiating, flexuous ribs which bifurcate a little above the middle of the 
side on some specimens, and branch into three or more divisions on others; 
ribs at first inclining forward, then backward, and finally forward upon 
approaching the ventral region. In the more finely sculptured specimens of 
this species the ribs are rather closely crowded together, while in others they 
are as much as 2 mm. apart. Both ribs and interspaces are rounded. The 
ribs do not continue across the ventral surface as a rule, but there are occa- 
sional thickened ridges, probably of the nature of varices, upon this surface, 
occupying the position of about each eighth or tenth rib. 

In Gabb's species, as figured in Pal. Cal., Vol. II, PI. XX, 
the ratio of the width of umbilicus to height of coil is i : 3, 
the umbilicus being relatively wider than in D. lecontei. 
The figure shown in Pal. Cal., Vol. I, PI. X, has even a 
wider umbilicus, and truthfully represents the specimen 
from which it was drawn. In Gabb's species, furthermore, 
the ribs are coarser, and the specimens do not show the 
varices on the ventral surface, clearly seen in D. lecontei. 


Some specimens collected at Horsetown that are possibly 
referable to this species have a diameter of 15 centimeters 
or more. 

Occurrence. — The type of this species was found in the 
Horsetown beds a little to the east of Hulen Creek, Shasta 
County, California. It is in the collections of the University 
of California. 

39. Desmoceras subquadratum, sp. nov. 
Plate IV, Fk;s. 118-119; Plate X, Fig. 193. 

Shell only moderately compressed; width of whorl nearly ecjual to depth; 
umbilicus not so wide as in last species, ratio of whole diameter to umbilicus, 
3.5:1; section of whorl subciuadrate; umbilical wall abrupt, broadly rounded 
on the back; surface of the cast nearly smooth, showing none or only faint 
constrictions; surface of shell marked by fine lines of growth and occasional 
varex-like ridges that form the flexures commonly seen on the shells of this 
group, bending more strongly forward in crossing the periphery; suture 
characterized by stout lobes and saddles, lateral lobes four or five in number 
on shells 7.5 cm. in diameter, decreasing uniformly in size toward the interior; 
first lateral lobe nearly equally tripartite, the others less so; saddles nearly 
equally bifid, with rounded terminations; width of shell increases with growth 
more rapidly than the depth. 

This species is possibly one figured by Gabb in the Pale- 
ontology of California (Vol. II, PI. XX) as Desmoceras 
hoffmanni (Pal. Cal.,Vol. II, PI. XX). 

Occurrence. — This shell is not uncommon in the upper 
portion of the Horsetown of Cottonwood Creek, Shasta 
County, California, near the mouth of Hulen Creek. Four 
of five good specimens were obtained at this place, some 
of which are in the collections of the University of 

The types of this and the preceding species, as here 
described, are in the collections of the University of 

40. Desmoceras colusaense, sp. nov. 

Plate V, Figs. 128-129; Plate X, Fig. 10a. 

In the collections of the State Mining Bureau in San 
Francisco is a magnificent example of a Desmoceras of the 
group D, flanulatiim^ nearly one foot in diameter. It is in 


perfect state of preservation though broken so that it can 
be taken apart, revealing the inner coils. 

The shell is discoidal and somewhat compressed when small, but increases 
in thickness very rapidly with growth; width of full grown whorl somewhat 
less than the depth; ratio of diameter to width of umbilicus, 3.3:1; walls of 
umbilicus rounded and sloping; section of whorl oval, sloping on the sides 
toward the periphery; surface ornamented by transverse, rounded ridges 
with the customary flexure, bending sharply backward within the umbilicus, 
and forward in crossing the ventral surface. On the younger coils about ten 
or eleven grooves are to be seen extending parallel to the lines of growth, 
and are plainest upon the ventral surface. The involution covers nearly 
two-thirds of the inner coils. The distinguishing features of this species are: 
(i) the oval section of the whorl; (2) the rapidly increasing thickness of the 
sliell after attaining a diameter of three or four inches; (3) the absence ot 
constrictions which appear on most of the species of this group; and (4) 
sutural characters. The suture of this species resembles in most points that 
of Desmoceras hoffmaimi, yet there is at least a specific difference which 
only a comparison will make clear. These dififerences are to be seen in the 
siphonal saddle, the divisions of the lateral lobes, and in the regularity of the 
small digitations on the lobes. There is less uniformity in the forward 
terminal limits of the saddles than appears in the figures. 

Occurrence. — This species evidently belongs to the 
Horsetown horizon. It was obtained from the Peterson 
ranch, in the vicinity of Sites, Colusa County, Cahfornia, a 
locality not yet very well known, and was found associated 
with Lytoceras batesi and other Horsetown species. 

41. Desmoceras dilleri, sp. nov. 

Plate IV, Figs. 116-117; Plate X, Fig. 192. 

Shell discoidal, but not compressed; umbilicus wide and shallow, walls 
rounded but abrupt, broadly rounded on ventral surface; ratio of greater 
diameter to width of umbilicus 2.5:1; width of whorls equal to depth; invo- 
lution a little less than one-half, that is covering less than one-half of the 
inner coils; surface marked by slightly flexuous lines of growth and about 
six shallow, transverse grooves which bend but little forward in crossing the 
ventral surface; sides of whorl slope somewhat rapidly toward the periphery. 
Suture line not minutely divided; both lobes and saddles rather broad; lobes 
not equally tripartite, saddles bifid. 

Occurrence. — Specimens of this species were obtained 
from near the mouth of Hulen Creek, Shasta County, 
Cahfornia. It belongs, therefore, in the upper part of the 
Horsetown horizon. 

The type is in the collections of the University of 


42. Desmoceras sugatum Forbes. 

Plate III, Figs. 98-99. 

Ammonites sugata Forbes, Trans. Geol. Soc. Lond., 2nd Ser., Vol. VII, 
1S45-56, p. 113, PI. X. Stoliczka, Paleont. Ind., Vol. I, p. 60, 

Desmoceras sugata Yokoyama, Paleontographica 34, p. 185, PI. XX. 

Among the interesting species comprising a small collec- 
tion of fossils from Shasta Valley is an undoubted repre- 
sentative of Amviomtes sugata, as described and figured by 
Stoliczka. The author had not access to the original de- 
scription of Forbes, and can only judge of its identity with 
the Indian species, trusting to the accuracy of Stoliczka's 
determination. The well preserved specimens from Siski- 
you County show clearly all the characteristics of the 
Indian type, and leave no room to doubt the essential 

The shell is discoidal, very involute, smooth, flattened upon the sides, 
keeled, and with narrow and deep uml)ilicus ; the keel is less noticeable 
upon the younger portion of the coil ; one or two faint flexuous grooves are 
seen near the aperture, bending considerably forward upon the ventral side. 
The suture line consists of many lobes and saddles, six of each being visible 
upon one side of the whorl and showing well their peculiarities ; saddles 
bifid, with ultimate divisions rounded ; lobes trifid, with numerous pointed 
denticles. The greatest diameter of the type specimen, which is probably 
not an old one, is 2.7 cm. On a portion of the outer whorl, in which the test 
is preserved, are faint lines of growth which curve strongly forward in cross- 
ing the keel, indicating that the aperture had upon its ventral margin a long 
projection or rostrum. These lines show also upon the cast of the shell, but 
more faintly. 

Ocair7'encc. — According to Stoliczka, Ammonites stigata 
occurs in both the Arrialoor and Trichinopoly groups of 
Southern India; Yokoyama reports it from a similar hori- 
zon of Japan; and in California it occurs in the Lower 
Chico beds of Siski3^ou County, from which the present 
specimens were obtained. At Henley, four specimens of 
this species were obtained along with Placenticeras calif or- 
nicum, P. facificiim, and very many others of the Lower 

The type is in the collections of the California Academy 
of Sciences. 


43. Desmoceras jugalis Gabh. 

Ammcmites jugalis Gabb (in part), Pal. Cal., Vol. II, p. 133, PI. XXII, figs. 
12, 12a and lib; not figs. 13 and 13a, same plate. 

Perhaps no other CaHfornia species has caused so much 
perplexity as Ammonites jugalis Gabb. In the Paleon- 
tology of California, three species are figured and referred 
to Ammonites jugalis. In the collections of the University 
of California were found eight small specimens in one tray 
labeled ^^ Am. jugalis Gabb," each with a label indicating 
its locality. One, the type of fig. 5, Plate X, Vol. I, is a 
typical Phylloceras ramosum Meek from the north side of 
Mount Diablo. Another, labeled "Pioche's Coal Mine," 
perhaps near Mount Diablo, is clearly a crushed specimen 
of sea-urchin, and has been recognized by Dr. J. C. 
Merriam as an example of a species recently discovered 
in the Martinez Group, and to which he has given the 
name Schizaster lecontei. This is apparently the speci- 
men from which Gabb' claimed to have drawn figs. 5 and 
6h^ which doubtless represent two distinct species of 
Ammonites. Of the other specimens, five are perhaps 
from Curry's, on the south side of Mount Diablo, and 
belong to a distinct genus, Schluteria, mentioned in 
another part of this paper, and the remaining one is a 
small crushed specimen of perhaps the same genus from 
Martinez. The species figured in the Paleontology of Cal- 
ifornia (Vol. II, PL XXII, figs. 12, 12(7, lib), should be 
selected as representing the type of Ammonites jugalis, and 
this is apparently the conclusion arrived at by Stanton 
(1895-96, p. 1031), who has studied the species carefully. 
There can be little doubt that figs. 13 and 13^^ are from 
a species not yet recognized, which is distinct from Am- 
monites jugalis. This is plainly seen in the sections and 
surface markings, as shown in the figures. 

1 Pal. Cal., Vol. II, p. 134. 

2 Pal. Cal., Vol. I, PI. X. 

^ Pal. Cal., Vol. II, PI. XXII. 


44. Desmoceras voyi, sp. nov. 
Plate III, Figs. 89-90. 

In the collections of the University of California are 
three specimens of a Desmoceras, each of a diameter of 
about 5 cm., two of which belong to the " Voy collection," 
and are labeled "Cottonwood"; the third is from the 
North Fork of Cottonwood, near Ono, Shasta County, 
California, where it was obtained by the writer. 

The general form is discoidal, though somewhat inflated; thickness of the 
specimens, about 2.5 cm., umbilicus narrow and deep, rounded on the 
ventral surface, toward which the sides gently converge; surface marked by 
many fine lines of growth which are flexuous and parallel to the six trans- 
verse grooves. These grooves are bordered behind by a ridge upon the 
shell, while they themselves are to be seen only, or ordinarily, upon the 
cast. The ridges become more prominent upon the periphery, where they 
bend strongly forward, forming a projection at the border of the aperture. 
The section of the whorl is elliptical in specimens of this diameter, though in 
the younger shells it is more nearly circular. The involution is deep, em- 
bracing more than tliree-fourths of the preceding whorl. The suture is a 
true Desmoceras suture, similar to that represented by d'Orbigny ' for Am- 
viofiites lalidorsatus, to which this species seems to be related. The sec- 
tional aspect, however, of Z>. voyi is much narrower than that of d'Orbigny's 
figures. There are also some resemblances between this species and 
D.jugalis Gabb;^ yet the differences will be seen to be greater than could 
be admissible for an identity without unusual evidence. 

Occurrence. — Desmoceras voyi belongs to the lower or 
central portion of the Horsetown beds of the Cottonwood 
section. Ammonites latidorsaUis Mich, is a species be- 
longing to the Gault, though it has also been found in the 
Ootatoor beds of Southern India, which are thought to be 
of Cenomanian age. 

45. Desmoceras ashlandicum, sp. nov. 

Plate IV, Figs. 107-109; Plate X, Fig. 196. 

Shell discoidal, compressed, not small, moderately involute, and coarsely 
ribbed; section of the whorl elliptical, narrowing gradually toward the 
periphery; umbilicus moderately large, and increasing more rapidly with 

iPal. Franc, VoL I, PL LXXX. 

s PaL CaL, VoL II, PL XXII, figs. 12, 12a and \ib. 


age; in young adult shells the walls of the umbilicus are abrupt, but are 
more sloping in younger, and more rounded in older shells ; the involution 
is moderate, one-half of each earlier whorl being covered. The ribs are 
mostly simple, only a few showing a disposition to bifurcate near the 
umbilical shoulders. Two-thirds or more of the ribs do not extend to the 
umbilicus, but arise from the middle of the side, or near the periphery, and 
cross the ventral surface, curving forward so as to produce an angle on the 
median plane. In age the ribs mainly disappear, or are reduced to about 
ten or twelve rounded ridges that are confined to the umbilical side of 
the whorl. The external side is then rounded and smooth. The diameter 
of the two largest shells found was about 25 cm. 

This species seems to be somewhat related to Puzosia 
darwini, as figured by Steinmann, from the Island of 
Quinquina, The constrictions that are shown upon Chile- 
an species, however, do not appear upon the casts of the 
one from Oregon. 

Occurrence. — Several specimens of this shell, one of 
which is the type, were found four miles southeast of Ash- 
land, Oregon. A similar shell that may belong to the 
same species was found at the Forty-nine Mine in Southern 

The type of this species is in the collections of the Cali- 
fornia Academy of Sciences. 

46. Holcodiscus, cf. H. theoboldianus Stol. 
Plate V, Figs. 126-127; Plate X, Fig. 197. 

In the Voy Collection at the University of California is a 
beautiful, well preserved specimen of an Holcodtsctis that 
very closely resembles the above species from the Tri- 
chinopoly group of Southern India. It belongs to the type 
of Ammonites incertus d'Orbigny, which comes from the 
Lower Cretaceous of Europe. Its sculpture exactly agrees 
with Haploccras cumshewaense Whiteaves, though its form 
is rather thicker. In this specimen the ratio of width of 
the whorl to height is about nine to one; in H. cumshewaense 
the ratio is said to be little more than five to one. 

The shell in the Voy Collection has a diameter of about 6 cm., which is a 
little more than three times the width of the umbilicus. The umbilicus has 
abrupt though not vertical walls, the involution exposes about one-half the 
(8) December 12, 1902 


side of the earlier whorls, the surface is ornamented with numerous fine trans- 
verse ribs which bifurcate about the middle of the side, or more often one-third 
of the distance from the umbilicus to the periphery. The ribs extend down- 
ward on the walls of the umbilicus, are only slightly inclined forward, and 
but little flexuous. The last whorl is crossed by five rather deep and 
rounded grooves, marking former positions of the mouth. These grooves 
follow the direction of the ribs, yet from their posterior margin three or four 
ribs arise at intervals and cross the periphery. This gives the constrictions 
an oblique appearance, yet on their anterior side they are exactly parallel to 
the next succeeding ribs. The grooves are bordered by ridges a very little 
stronger than the ribs ordinarily, and the anterior one forms a sharp promi- 
nence where it crosses the umbilical shoulder. The suture line is quite 
complex, consisting of four or more bifid saddles, very finely divided, ter- 
minating in rounded denticles, and diminishing regularly in size toward the 
umbilicus. The trunk and branches of the trifid lobes are relatively wider 
than the corresponding parts of the saddles, and terminate in pointed, finger- 
like teeth. The auxiliary lobes have an oblique direction, and are relatively 
wider than the main, or first lateral lobe. The suture line agrees very well 
with Stoliczka's figure in the main, but the dissection of the saddle is more 

Occurrence. — It is unfortunate that this interesting spe- 
cies cannot be more definitely located than a general refer- 
ence to Cottonwood Creek, Shasta County, California. 
The sandy character of the matrix, however, suggests that 
it probably comes from an upper horizon of the Cretaceous 
section of that place. 

47. Pachydiscus newberryanus Meek (not Gahh). 

Ammonites newberryanus Meek. Trans. Albany Inst., Vol. IV, 1857, 
p. 47; Bull. Geol. Sur. Terr., Vol. II, 1876, p. 367, PI. IV, figs. 3, 3a, 
3<5. VVhiteaves, Mes. Foss., Vol. I, 1879, p. 109, PI. XIV. 

Afnmonites fraterniis GhBH, Pal. Cal., Vol. II, PI. XXIII. 

In the collections of the University of California are two 
or three specimens of this species from Pence's ranch, 
Butte County, California. These were carefully compared 
with a typical specimen from the Sucia Islands, in the 
Straits of Georgia, British Columbia, borrowed from the 
collections at Stanford University. 

The normal development of this shell is characteristic. In youth, at a 
diameter of three to four centimeters, the section of the shell is almost circu- 
lar, though involute to the extent of covering nearly one-half the earlier 
whorl. The ribs are simple or obscurely bifurcated in part; half of them 


arise from within the umbilicus and pass outward to the ventral side, while 
some of them arise from tubercles upon the umbilical shoulders. About six 
constrictions cross the outer whorl transversely, bordered by ridge-like ribs 
behind. As the shell increases in diameter it becomes rapidly more dis- 
cpidal, narrowing toward the ventral edge. The ribs curve more strongly 
forward in approaching the siphonal margin, the tubercles upon the umbil- 
ical shoulder become obsolete or indistinct, and the height of the whorl 
increases considerably. The more inflated form of the young shell of this 
species is probably represented by Gabb's species, Ammonites fraternus} 

Occurrence. — The species belongs to the upper portion 
of the Chico beds, having a wide distribution in this 

48. Pachydiscus merriami, sp. no v. 
Plate VI, Figs. 135-138, 
cf. Ammonites suciaensis Gabb (not Meek), Pal. Cal., Vol. I, PI. XXVII. 

Shell robust, but little compressed, rounded on the abdomen, and with 
small umbilicus; walls of umbilicus abrupt within, rounded upon the 
shoulders, deep and somewhat funnel form; width of umbilicus less than 
one-fifth the whole diameter of the shell; somewhat flattened upon the sides, 
rounded broadly over the ventral surface, and very thick; surface marked 
with about eight transverse, shallow grooves, which are seen only upon the 
casts, while upon the shell itself there are as many rounded ridges that 
border these grooves in front; ridges more prominent upon the ventral 
surface and almost disappearing upon the sides; lines of growth distinct 
between the ridges. 

The measurements of the largest specimen found are: diameter, 9.7 cm.; 
greatest thickness, 4.7 cm.; width of umbilicus, 1.7 cm.; depth of involution, 
1.7 cm.; height of last whorl from umbilicus, 4.8 cm. The suture consists of 
two principal and three smaller auxiliary lobes, diminishing rapidly in size. 
Both lobes and saddles are much divided, the saddles consisting in their 
final divisions of broadly denticulated digitations that are somewhat spatulate 
in form. The terminal branches of the lobes are narrowly acuminate. 
Shells of this species are nearly spherical at a diameter of i cm., with a 
reniform section; the depth of whorl becoming proportionately greater with 
age. In crossing the sides of the whorl the grooves curve at first gently 
backward and then forward, and approach the median plane obliquely. 

This species is probably the one which Gabb found 
upon the Cottonwood, in Shasta County, California, and 
referred to as ^. sticia'cnsis Meek. The figure in the Pale- 
ontology of California,^ however, was drawn from a speci- 

1 Pal. Cal., Vol. 11, p. 137, PI. XXIII. 

2 Vol. I, PI. XXVII. 


men brought from Vancouver Island, and represents 
neither A. siiciaensis nor A. tnerriami ; yet perhaps they are 

The type represented by Gabb's figure, however, has 
actually been found in the Lower Chico beds of the 
Oregon basin, at Henley, Siskiyou County, and is de- 
scribed in the following pages as Pachydiscus henleyensis. 

Occurrence. — Pachydiscus merriami belongs near the top 
of the Horsetown horizon. Three samples, representing 
successive stages in its growth, were obtained from the 
Upper Horsetown beds of Hulen Creek, Shasta County, 

The types are in the collection of the University of Cali- 

49. Pachydiscus henleyensis, sp. nov. 
Plate VIII, Figs. 165-166. 

Ammonites sucia'ensis Gabb (in part). Pal. Cal., Vol. I, Pis. XXVII and 

Shell robust, inflated, section of whorl broader than high, being reniform, 
the ratio approximately nine to five; the umbilicus narrow, with rounded 
shoulders; surface crossed by low, rounded ridges flattening and growing 
in number toward the ventral side; sides of young shell moderately even, 
and rounded in section, but flattening with age and breaking up into broad 
undulations which appear to arise with growth from heavier ribs placed at 
intervals, hardly noticeable on shells below a diameter of 15 centimeters. 
The suture line is well represented by Gabb's figure, the lobes being narrow 
and exceedingly divided. 

Gabb's figure of this species is from a specimen about 
five and one-half inches in diameter, a size intermediate 
between the two that are represented in the sections given 
for P. henleyensis. The section published by Gabb is evi- 
dently not accurately drawn, showing too great an involu- 
tion. A correction of this error shows the section of 
Gabb's specimen to be intermediate to those given here, 
which were both drawn from one specimen at different 

Occurrence. — Two specimens of this shell were found 
at Henley, Siskiyou County, California, in the Lower 


Chico beds of that place, the larger one being about thirty- 
two centimeters in diameter, but not altogether perfect. 

The types of this species are in the collections of the 
California Academy of Sciences. 

50. Pachydiscus sacramenticus, sp. nov. 

Plate VI, Figs. 133-134; Plate X, Fig. 195. 

Shell discoidal, not compressed, of moderate size; section of whorl sub- 
elliptical, truncated at umbilicus, rounded sides sloping very gently to meet 
rounded ventrum; umbilicus wide, walls sloping steeply, involution covering 
one-half of inner whorls; surface marked by narrow, sinuous ribs curving 
gracefully forward in crossing ventral surface, most prominent at two-thirds 
distance from umbilicus to siphonal plane; ribs separated by wide grooves, 
which do not extend to umbilicus, and diminish on ventral surface; minor 
lines abundant between larger ribs; body chamber occupying two-thirds of 
entire outer whorl, increases but gradually in size with age; ratio of umbilical 
dimension to diameter thirty-three one hundredths; width of whorl eighty- 
four one hundredths of depth; suture of large whorl not seen. 

This shell Dr. Stanton thinks is a Pachydiscus, and 
the suture, so far as it can be seen, agrees with that 

Occurrence. — The species belongs apparently to the 
upper portion of the Horsetown. The type was obtained 
upon an east branch of Hulen Creek, Shasta County, Cal- 
ifornia. Another smaller specimen, thought to be identical 
with this one, was found at Horsetown. 

The type of the species is in the collections of the Uni- 
versity of California. 

51, Sonneratia stantoni, sp. nov. 

Plate III, Figs. 91-93. Plate X, Fig. 198. 

Shell small, not often above a diameter ot 3.5 cm., discoidal, laterally com- 
pressed and flattened; sides converging gently toward the periphery; ventral 
surface rounded or subquadrate; umbilicus not large, less than one-third the 
total diameter, generally funnel-form, owing to its sloping sides and the 
increasing thickness of the shell; surface ornamented with about thirty 
transverse flexuous ribs which usually cross the ventral surface and ter- 
minate in about half as many distinct tubercules upon the shoulder of the 
umbilicus. The ribs show a tendency to bifurcate from these ridge-like 


tubercules, become considerably depressed upon the sides of the shell, 
curve gently backward, and become more prominent and wider near the 
outer margin, where the curve is again decidedly forward. The surface of 
the shell, both on the ribs and in the intervening rounded hollows, shows fine 
striations which are parallel always to the ribs. The suture line is simple, 
consisting of a few broadly-rounded saddles and wide lobes having very 
short branches. The saddles are but little indented, and are bifid with 
rounded denticles and incisions. Lobes unequally tripartite. 

There appears to be considerable variation in the shells 
of this species, some of them being much more compressed 
and nearly without ribs, while others simply lack the ribs 
and retain their normal thickness. One specimen in 
which this variation is extreme, in addition to being almost 
without ribs or tubercules, has its septa so crowded 
together as to render them nearly indistinguishable, which 
does not seem to be true of the great majority of speci- 
mens. Dr. T. W. Stanton, to whom some specimens of 
this species were submitted, thinks it probably belongs to 
the genus Sonneratia Bailey; and in recognition of the 
valuable contributions he has made to the study of West 
Coast Cretaceous, the above name for this abundant and 
interesting species is proposed. 

Occurrence. — This shell is common in the vicinity of 
Horsetown, Shasta County, California, though it has not 
been reported from corresponding horizons elsewhere. It 
belongs, therefore, to the upper portion of the Horsetown 
division of the Cretaceous. 

The type of the species is in the collections of the Uni- 
versity of California. 

52. Stoliczkia dispar (d'Orb.) Stoliczka. 

cf. Ammonites dispar d'Orb., Pal. Franc. Terr. Cret., I, PI. XLV. 
Ammonites dispar (d'Orb.) Stol., Pal. Ind., Vol. I, p. 85, PI. XLV. 

The many descriptions of d'Orbigny's species referred 
to by Stoliczka have not been accessible for comparison, 
but the identity of the Indian species with one in the col- 
lections of the University of California from the Shasta 
beds cannot be doubted. There is so close an agreement 


in every particular that little hesitation is felt in stating the 
identification. A quotation from Stoliczka's description is 
applicable to the California species exactly. He says: 
"The small tubercles on the edge of the back of the young 
shell, the unequally longer and shorter ribs, the nodular 
ribs on the back of the body chamber, the irregular evolu- 
tion of this last chamber, the division of the septa," — all 
these characters which have been recognized in the Indian 
examples are clearly seen also in those from California. 

Occurrence. — This species comes from the Horsetown 
beds of Cottonwood Creek, Shasta County, California. 

53. Acanthoceras compressum, sp. nov. 

Plate IX, Fig. 1S7. 

Shell small, compressed or discoidal; average diameter of adult shell about 
4.5 cm., greatest thickness 1.5 cm.; height of whorl about twice the width of 
umbilicus, which is about one-fourth the diameter of the coil; surface marked 
by flattened and rather flexuous ribs, of which there are about thirty-two in a 
complete adult whorl; ribs often considerably reduced in strength, especially 
on the sides of the shell, and ornamented at each extremity with rows of 
prominent nodes. Along the margin of the umbilicus these tubercles are 
rather high and narrow, inclining forward, while at the ventral termination of 
the ribs the prominent linear nodes are often parallel to the median plane 
in their arrangement. A secondary row of tubercles, less pronounced in 
appearance, occupies a position inside the marginal row, each one forming a 
point from which the rib bends rather sharply forward. The ventral surface 
is flattened or only slightly convex between the marginal nodes, and is gen- 
erally crossed by faint undulations which are the continuations of the ribs. 
The median row of nodes sometimes noticed in species of this genus does 
not appear on any of the specimens of this shell. 

A. compressum is no doubt very closely related to 
Am. rhotomagensis (var. compressus) Stoliczka, and per- 
haps might be included in that species with no greater 
stretch of Stoliczka's definition; but there does not seem 
to be sufficient reason to include all of his four varieties in 
a single species, while at the same time other forms are 
excluded. A. compressum has a near ally in a species 
from the Lower Chico beds of Southern Oregon, referred 
to Acanthoceras rhotomagense, which very probably belongs 


to the variety showing a median row of nodes upon the 
abdominal surface, as shown in d'Orbigny's figures^ and 
in some of Stoliczka's.^ 

Occurrence. — Acanthoccras corner essum is found in the 
Lower Chico beds of the Santa Ana Mountains, Silverado 
Canon, and at Bowers Canon, in Los Angeles County, 

The type was obtained from the latter locality by Dr. 
Stephen Bowers of Los Angeles. It is at present in the 
collections of the University of California. 

54. Douvilliceras mamillare Schloth. 

Acanthoccras mamillare Schloth, Pal. Franc. Terr. Cretac, T. I, PI. 

Acanthoccras mamillare (?) (Schloth) Stanton, Bui. Geol. Soc. Am., 

Vol. V, 1894, p. 445. 
cf. Atnmonites mantelli (Sow.) Stoliczka, Pal. Ind., Vol. I, p. 81, PI. 

XLII, figs. I and la. 
Ammonites stoliczkamis (?) Gabb, Pal. Cal., Vol. II, p. 135, PI. XXIII. 

In the upper Cretaceous beds of Clear Creek and the 
Cottonwood Creek, Shasta County, California, this spe- 
cies is somewhat common. It occurs here in beds evidently 
quite similar to the Cenomanian, being found both in the 
Lower Chico and the uppermost Horsetown. 

Among the collections at the University of California are 
a number of specimens of AiJimonites mamillare from 
France, and a comparison of these with several well pre- 
served types from Shasta County shows few differences, 
and the very strongest resemblances, between them. 
There is the same general form and ornamentation ; the 
same width and depth of umbilicus, and involution of 
whorls; the tuberculation on both is identical, and goes 
through a cycle of development the same in both cases. 

At a diameter of 2-3 centimeters (in the Shasta specimens) the ornamenta- 
tion of the ribs consists of spinose tubercles in three rows. One of these 
rows is upon tlie umbilical shoulder, one upon the ventral surface upon each 
side of the median plane, and a third upon the middle of the side, where it 

1 Pal. Franc. Terr. Cret., I, PL CV. 

2 PaL Ind., VoL I, PL XXXIV. 


forms a sort of angle. These tubercles are not generally found upon all the 
ribs, but are often upon only alternate ones. As the growth of the shell pro- 
ceeds, these rows become series by the development of other secondary 
tubercules that cause a doubling or trebling of the rows. This is more par- 
ticularly so with the external row. At the diameter of 5 or 6 centimeters, 
these tubercules appear to reach their maximum development and form 
almost a continuous series from the umbilicus outward, which has its greatest 
height upon the ventral side. Above this diameter they gradually decline in 
prominence and at the diameter of 12 centimeters they become obsolete. 
The form of the shell also changes with age and becomes less angular and 
more rounded in section. The suture line consists of three saddles and two 
lateral lobes with one or two auxiliary lobes and saddles within the umbilical 
angle. The first lateral saddle is very prominent. The saddles are broad 
and are not deeply incised, the lobes are unequally bifid, the longer division 
terminating in a long, narrow digit with short branches and denticles. 
D'Orbigny's figure represents this form quite perfectly. 

The figures and description of Acanthoceras s^miferiLin'^ 
Whiteaves agree with this species perfectly as it occurs in 
the California beds, and the differences between the 
Queen Charlotte Island specimen sent to Kossmat and the 
European species seem to be unimportant. In fact, the 
features upon which the distinction is founded do not seem 
to be constant for either the European samples, or those 
obtained from California. 

This shell is not uncommon at Horsetown and at Hulen 
Creek, a few miles to the west. 


Until now the genus Scaphites has been all but unknown 
in the Pacific border province of America, though it is well 
represented both in the Cretaceous of Southern India and 
in that of the upper Missouri, from either or from both of 
which sources it may have been derived. It is therefore of 
some interest to find at last within the limits of the West 
Coast Cretaceous no less that six species of this shell so 
characteristic of many marine Upper Cretaceous deposits. 

In the rich fossil beds of Southern India this genus is 
most abundant in the lower horizon, the Ootatoor, which 
has been correlated with the Cenomanian of Europe. In 

1 Mes. Foss., Vol. I, Pt. IV, p. 273, PI. XXXV. 


the upper Missouri beds it belongs to beds that are 
regarded as Turonian in age. The members of the genus 
that have been found in the Oregon basin are, at least in 
two or three cases, closely allied to those of the upper 
Missouri, with which they may have probably genetic rela- 

55. Scaphites gillisi, sp. nov. 

Plate III, Figs. 85-88. 

It is only after considerable study and comparison that 
this fine little Scaphite has appeared to be entitled to a 
distinct specific name. There are in the collections of 
the University of California five perfect examples of S. 
warreni M. & H. from the Upper Cretaceous of Dakota. 

In form and ornamentation the above species agrees so closely with 
that from the upper Missouri that at first it seemed indistinguishable from 
it except by its smaller size and generally smoother shell. The transverse 
costae of S. warreni are not only sharper and stronger, but the lateral ridge- 
like nodes are also more numerous and more prominent. In form S. gillisi 
is more quadrate in outline, being at the same time proportionately longer 
and narrower than the species of M. & H. As to the sutures in S. gillisi, 
the lateral lobes are relatively wider and more developed; the first lateral 
saddle is more deev)ly divided, and the siphonal lobe and its subdivisions 
are both deeper and more strotigly incised. While in general the form of 
the suture is very similar to that of .S". warreni, it is at the same time more 
complex in detail. 

There will hardly be a doubt as to the near relation of 
the species S. gillisi and S . -warreni, and whether identical 
or not it serves to strengthen the connection between the 
deposits of the Oregon basin and those of the Colorado 
group, in which the latter is found, and to ally them both 
to the Cenomanian. S. gillisi is more distantly related to 
S. csqualis Sowerby, and agrees fairly well with some of 
the types figured by StoHczka,^ except that the shell is 
thicker in transverse section, is more quadrate in outline, 
and has simpler sutures. It lacks the peculiar ventricose 
development of the body-chamber seen in d'Orbigny's 
figures, though in other respects there is considerable 

1 Pal. Ind., Vol. I, PI. I^XXXI, figs. 4 and 6. 


agreement. Meek also states a similar relationship for 
S . luarreni. 

The type is in the collections of the CaHfornia Academy 
of Sciences. 

Occurrence. — This species, with its associates, is from 
the Upper Cretaceous beds of Shasta Valley, which in their 
stratigraphic position correspond very nearly to the fossilif- 
erous beds of the Forty-nine Mine, near Phoenix, in Roo-ue 
River Valley, Oregon, and to the Lower Chico beds of 
Shasta County and the upper Sacramento Valley, Califor- 
nia. The name is proposed in recognition of the general 
and intelligent interest taken in geological science by the 
donor, Mrs. H. B. Gillis of Yreka, who has contributed 
materially to the present study. 

56. Scaphites condoni, sp. nov, 

Plate II, Figs. 58-63. 

Shell small, type specimen 2.5 cm. in length, r.6 cm. in width, moderately 
inflated, especially at the recurved portion, where the section of the body- 
chamber is almost circular; outline of shell subquadrate, inclining to oval; 
surface ornamented by both ribs and nodes. The body-chamber is crossed 
just behind the deflected portion by thick transverse ridges with intervening 
constrictions, which are, however, confined to the sides of the shell and are 
most prominent upon the middle zone, though extending to the umbilicus 
and to the row of small tubercules bordering the ventral area. The posterior 
part of the body-chamber is flattened upon the sides and forms a dorsal 
expansion which almost covers the otherwise open umbilicus. The coiled 
portion of the shell is crossed by numerous transverse, slightly curved ribs 
extending from the umbilical border and branching a little below into two or 
more divisions. Each of these branches terminates in a node upon the ven- 
tral margin of the side, from which arise two or more finer ribs crossing the 
ventral area. Upon the sides of the body-chamber these ribs do not appear, 
except in the most posterior portion. The nodes upon the ventral shoulder 
of the whorl first appear at a diameter of near i cm., becoming most promi- 
nent upon the body-chamber. Along the ventral margin of its sides these 
nodes show a tendency to become pointed or spinose tubercules which incline 
outwards, forming a flattened ventral surface. From these tubercules, which 
are triangular in form, originate small ridges, scarcely noticeable, which cross 
the ventral portion of the body-chamber. Neither nodes nor ridges, how- 
ever, are found upon the recurved portion of the shell. Back of the aperture, 
which is partly closed by a strong constriction, is a conspicuous expansion or 
thickening of the shell, forming a lip-like ridge surrounding the mouth. The 


umbilicus in the younger coils is wide, the whorls being little involute and 
almost circular in section. With increasing age the whorls become more 
clasping, until at maturity the umbilicus is almost, though never entirely, 
closed. The ribs form at a diameter of about .8 cm. 

The suture line is simple, consisting of but few bifid lobes and saddles, the 
latter of which are rounded in their smaller divisions, and in general outline, 
while the former are narrow and pointed. 

Occurrence. — This species was collected with the follow- 
ing at the Forty-nine Mine, near Phoenix, Oregon. Its 
horizon is equivalent to that of the Lower Chico of the 
Sacramento basin. 

The type is in the collections of the California Academy 
of Sciences. 

The species is named in honor of Professor Thomas 
Condon of the University of Oregon. It is with pleas- 
ure that a tribute of recognition is thus offered for the 
deep interest and devotion to geological study which 
has so often been a source of inspiration alike to students 
and acquaintances. 

57. Scaphites condoni var. appressus, sp. et var. nov. 

Plate II, Figs. 64-66. 

This shell is quite evidently a variety of the preceding, 
and it will be only necessary to mention here its points of 

In general it has a thinner and more compressed form. The transverse 
ridges and constrictions upon the body-chamber are farther forward than 
those upon the type of the species, and have, moreover, a decidedly obHque 
tendency. The transverse ribs upon the coiled portion of the shell are 
scarcely to be seen. The suture line seems to be a little more developed, or 
complex, in its details, but otherwise is identical with that of the type. 

Occurrence. — The position and occurrence of this shell 
is the same as that of the preceding. 

The type is in the collections of the California Academy 
of Sciences. 

58. Scaphites roguensis, sp. nov. 

Plate II, Figs. 67-70. 

Shell small, discoidal, flattened on sides, quadrate in section; umbilicus 
small in adult shell, relatively wider when young; surface of shell nearly 


smooth on body-chamber, coiled portion crossed by many transverse costae; 
ventral shoulders of body-whorl ornamented by small, oblique tubercules; 
dorsal edge of body-chamber expanded over the umbilicus. 

Length of shell, 2 cm.; width, 1.5 cm.; greatest thickness, .6 cm. Septation 

This shell is apparently related to the preceding, 
though it has not the characteristic constrictions of that 
species, and is more flattened on the sides. 

Occurrence. — Found with the preceding in the Lower 
Chico beds of the Forty-nine Mine, near Phoenix, Oregon. 

The type of this species is in the collections of the 
California Academy of Sciences. 

59. Scaphites inermis, sp. nov. 

Plate III, Figs. 74-77. 

Shell small, compressed, elliptical in outline, smooth, and almost without 
ornamentation. Umbilicus open and wholly uncovered; whorls litde invo- 
lute, ne\^er clasping one-half the preceding whorl, and subcircular in section 
throughout; body-chamber, however, a little deeper than wide though 
quadrate; squared or truncated on the dorsal side. The sides of the body- 
chamber are obliquely crossed by faint transverse, and apparently bifurcating 
ribs, which continue uninterrupted across the ventral surface. On both the 
umbilical and ventral shoulders of the body-whorl there are small linear 
nodes that are almost obsolete on some specimens and hardly appear at all 
upon the coiled portion of the shell; aperture having a ridge-like rim, hardly 
a lip, surrounding it, behind which is a shallow constriction, both of which 
curve backwards at the inner angle of the whorl. On each side of the aperture 
a small auricular expansion extends forward from near the dorsal edge of the 
mouth, forming a small triangular surface showing faint concentric strise. 

It is thought worth while to note that upon one specimen, 
which was accidentally broken, the "impressed zone" of 
the body-chamber was well exposed. Although the body- 
volution was entirely free from the earlier coil, this dorsal 
zone, which had appeared to be squared or truncated, yet 
contained, as far as the margin of the aperture, a shallow, 
though distinct groove. 

Occiirrencc. — This species is abundant at the Smith 
ranch, and has been found also at the Forty-nine Mine, 
near Phoenix, Oregon. 


60. Scaphites perrini, sp. nov. 

Plate II, Figs. ti~T2>- 

The most remarkable species of Sca^phites that has been 
discovered at localities in Southern Oregon was collected 
recently by Dr. James Perrin Smith, in whose honor the 
above name is proposed. 

Unlike other known types of this genus, most of which are inclined to be 
discoidal, at least in some stages, S. perrini seems to be at no stage either 
discoidal or merely gibbous or inflated. 

The shell is small, being little over 1.2. cm. in length, .9 cm. in greatest 
width, and .65 cm. in greatest thickness. 

The section of the whorls, though not entirely visible, seems to be trans- 
versely elliptical, or "digonal" with each " lateral angle " forming the margin 
of a funnel-form umbilicus. The ventral surface is broad, extending to the 
umbilical angle, rounded, and nearly smooth. The aperture is reduced by a 
strong, rounded constriction which extends a little beyond the umbilical 
angles, and is bordered in front by a sharp elevation or ridge. From each 
side of the aperture large lateral ears extend forward, almost touching the 
lateral angles of the preceding whorl, and reducing the form of tlie aperture 
to subquadrate. The surface ornamentation of this species consists of small, 
simple ribs, which do not appear to cross the wide ventral surface, or else 
cross it only as fine lines, not visible upon the cast. These ribs are most 
conspicuous upon the lateral angles of the whorl, which they cross, forming 
small nodes, from which they incline obliquely backward on both the um- 
bilical and the external surfaces. 

The suture line, which can be traced only across the rounded ventral 
surface, is simple, consisting of broad saddles and narrow lobes, both of 
which are bifid in their subdivisions. The siphonal lobe is simple, being 
almost as wide as long, having one lateral and one terminal branch. The 
first lateral saddle is quadrate in outline, and subdivided into two unequal 
portions, which are again indented or divided in a similar manner. 

Occurrence. — S. perrini is known only from a single, 
though nearly perfect, specimen, obtained recently from 
the Smith ranch, near Phoenix, Oregon, by Dr. J. P. 
Smith, through whose courtesy the author has been per- 
mitted to describe it. It is from beds that are equivalent 
in their horizon to those of the Lower Chico of the Sacra- 
mento basin. 

The type is in the collections of the Leland Stanford Jr. 


61. Scaphites klamathensis, sp. nov. 

Plate III, Figs. 78-81. 

Shell small, compressed, ovate in outline, measuring only 1.3 cm. in length, 
.9 cm. in width, and .35 cm. in greatest thickness. Umbilicus not wide; 
whorls clasping generally about one-half of the preceding volution in youth 
and apparently suppressing the umbilicus in age; section of whorls sub- 
circular or subquadrate, flattened on the dorsal side of the body- whorl, 
which is somewhat inflated in the region of the bend. The surface is orna- 
mented with fine ribs or striations, which cross the ventral surface and con- 
verge toward small nodes near the umbilical margin of the whorl. These 
ribs are seen only upon the body-chamber, and the nodes appear only upon 
the last two-thirds of the same. The suture is simple, consisting of a large 
siphonal lobe and a very much smaller lateral one, with one or two sec- 
ondary lobes. There is one lateral saddle upon the inner side of which is an 
indentation that might pass for an auxiliary saddle. 

The aperture of this species deserves special notice. It is bordered by a 
distinct lip which is immediately preceded by a rather wide and shallow con- 
striction which extends upward toward tUe dorsum without apparently 
reaching it; from each side of the aperture a wing-like expansion extends to 
the preceding coil, against which it rests, thus reducing the aperture to an 
oval opening upon the ventral side of the shell. The surface of these expan- 
sions are ornamented with concentric undulations that begin at the middle of 
the mouth-border, i. e., at the middle of the side of the aperture. 

In all respects except as to size and form of aperture, 
S. klamathensis exactly agrees with S. larv<^formis M. & H. 
from the lower portion of the Colorado group of the upper 
Missouri. Meek and Hayden's figures do not show the 
buccal border, and apparently it was not known. There 
is reason to believe that S. klamathensis is only a small 
form of S . larvcBforniis, but until this can be more satisfac- 
torily shown, it seems preferable to designate the Shasta 
Valley species by a separate name. It is also related to 
S. I tier mis. 

Occurrence. — This species is one from the small collec- 
tion presented to the author by Mrs. H. B. Gillis of Yreka, 
and comes from the northern border of Shasta Valley, to 
the south of the Klamath River. 

The type is in the collections of the California Academy 
of Sciences. 


An important addition to the number of species of 
SchlcBiibachta^ hitherto known from the West Coast will be 
recognized in this paper. No less than ten distinct forms 
have been found in the Chico beds of Northern California 
and Southern Oregon. It is possible that with further 
searching still others will be discovered, since each new 
collection of them contains some new species not met with 

In the Lower Horsetown beds representatives of this 
genus have not been found, but in the Upper Horse- 
town is the Cenomanian species, S. injlata. In the Upper 
Chico are S. chicoensis Trask, S. gahbi, sp. nov. and 
S. buttensis, sp. nov. By far the larger number, however, 
are found in the Lower Chico beds, and principally in the 
Oregon basin. With the exception of a single species, 
S. chicoensis, there is but little resemblance between those 
of the two adjoining basins. 

Most of the species described in this paper fall without 
much question into the genera recognized by Zittel in his 
later work.^ Four of the genera are represented by two 
or more species each. There are other forms, however, 
that admit of such grouping with more difficulty. In some 
of them the keel entirely disappears in old age, or even 
before mature age is reached. 

62. Schlcenbachia chicoensis Trask. 

Plate I, Figs. 21-22; Plate II, Figs. 23-25. 

Ammonites chicoensis Trask, Proc. Cal. Acad. Sci., Vol. I, 1856, p. ^, 
PI. II. 

From a careful study of this species with others nearly 
related, it is evident that there has been a confusion enter- 
tained by some of the earlier writers upon the paleontology 
of California. The figures and description of this species 

^Schlcenbachia is used in this paper in the broad sense originally defined by Zittel in 
his "Traits de Paleontologie," 18S7. 

""Grundziige der Palreontologie," 1895. 


b}' Gabb can hardly be made to agree with those of Trask 
(1. c). The description of neither species can be consid- 
ered satisfactory; yet enough is shown and told to make it 
evident that two species, and not one, have been described 
under this name. 

In Trask's species there are about twenty-four distinct 
and simple ribs, bearing a double row of tubercules near 
the outer margin of the coil. The ribs do not bifurcate 
upon the sides, but seem to consist of two kinds, primar}- 
and auxiliary. The latter do not extend to the umbilicus, 
but disappear a little above the middle of the sides, and 
extend to the outer margin. No statement is made as to 
the relative size of the umbilicus, but in Trask's figure it 
appears to be more than one-third the diameter of the 
entire coil. The section of the whorl is oval rather than 
flattened, as in Gabb's species. 

The specimen figured by Trask was probably an imma- 
ture one, and there is room for a considerable change in 
these features during a more complete growth; yet the 
changes would hardly be of the nature which Gabb's 
figures indicate. There is in the collections at Berkeley a 
small specimen, labeled as coming from Trask's original 
locality, which agrees tolerably well with his description 
except in the number of ribs, which is slightly greater. 
Trask's species also seems to be much less common than 
Gabb's, or it has not been definitely recognized. 

Occurrence. — Trask's specimens came from the Upper 
Chico, on the eastern side of the Sacramento Valley, and 
from the locality of Chico Creek, and Pence's ranch, 

63. Schloenbachia gabbi, sp. nov. 

Ammonites chico'ensis Gabb (not Trask). Paleontology' Cal., Vol. I. p. 68, 

In the collections of the University of California are 

several well-preserved casts of Gabb's species of this shell 

from the original localities of both Trask and Gabb. They 

are identifiable without great difficulty from Gabb's figures 

and description, with which they agree fairly well in most 


(9) December 22, 1902. 


The larger shells are almost squarely truncated at tlie ventral margin, the 
keel often being very slight, though always visible. The sides are flat- 
tened or gently convex, and ornamented with about forty-five to fifty ribs 
counted along the ventral margin, where they terminate in flat, transverse 
tubercules. On the umbilical margin of the whorl there is a prominent row 
of tubercules not shown in Gabb's figure, though mentioned in the text, from 
which the umbilical wall makes a perpendicular descent. The costal nodes 
are not always very conspicuous upon the casts, though three or four rows 
can be distinctly made out. 

The young shells of this species, unlike those of Trask's species, are 
almost perfectly smooth, showing neither ribs nor costal nodes until they 
attain a diameter of more than 2 cm. Gabb seemed lo have noticed this 
fact, though without attaching to it the importance which it deserves. The 
specimen figured by Trask had a diameter of 1.5 cm., yet distinctly showed 
twenty-four strong ribs. In the young shell of Gabb's species the umbilicus 
has a diameter of less than one-fourth that of the entire coil, and the section 
of the whorl is narrow and elongated, and rather squarely truncated on both 
dorsal an<l xenlral margins. 

The largest specimens of S. gabbi in the collections of the University of 
California have a diameter of 10 cm., and at that size the ribs have almost 
disappeared, together with the nodes upon the sides of the sliell. 

The above name is proposed to distinguish this species 
from that for which it has evidently been mistaken. There 
are some varieties of the species that deserve mention, one, 
especially, in which the sides are more than ordinarily 
convex, and in which the ventral truncation is somewhat 

64. Schlcenbachia buttensis, sp. nov. 

Plate IV, Figs, no, in. 

This species is related to S. gabbi, though it is evidently a distinct form. 
The ribs, about fourteen in number, counted along the umbilical shoulders, 
.are nodose and bifurcating. The nodes are in five rows upon the sides of 
the shell, and in this respect it resembles its congener, .S. gabbi, but the 
umbilical row is much more elevated and narrow, and the ribs are more 
disposed to bifurcate. This takes place from either of the three inner rows 
of nodes. The nodes of the outer row are sharp and ridge-like, forming 
upon the periphery a flattened, ventral surface, as shown upon the cast. The 
keel is low and apparently entire; septation not well known. 5". buttensis 
is also related to S. varians Sowerby. 

The figure was drawn from an imperfect specimen, 
immature in size, 3'^et sufficiently large to show the specific 


Occurrence. — The species is an associate of the preceding 
one, S. gabbi, and belongs to the Upper Chico of Pence's 
ranch, Butte Count}^ California. 

The type is in the collections of the University of 

65. Schloenbachia siskiyouensis, sp. nov. 
Plate I, Figs. 19-20. 

Shell discoidal and compressed; umbilicus of young coils about one- 
third the whole diameter, becoming relatively narrower v\ith increasing age; 
keel at first simple, but at a diameter of i cm. begins to break up into nodes, 
which at 3 cm. become entirely separated by moderately wide intervals. On 
the older shells the segments of the keel form high and narrow tubercules 
which have a definite and regular position with reference to the ribs. The 
ribs are simple, about twenty-five in number, and are of two orders. The 
first originate in the prominent tubercules along the umbilical margin of the 
whorl, and, bifurcating from that point, terminate in the outer row of 
tubercles along the ventral margin. The ribs of the second order make their 
appearance between the pairs of the first. Thus, about every third rib 
arises from a little above the middle of the side, without extending to the 
umbilicus, and terminates as do the others, in the external row of tubercules. 
This outer row of tubercules forms a series of distinct and pointed prom- 
inences that diverge slightly from the plane of the keel. A little abo\e these, 
upon each rib, is developed a distinct prominence which forms the thickest 
portion of the rib, and which is separated from the outer, or marginal node, 
by a shallow though visible depression. The ribs are inclined to be straight, 
except where on approaching the outer margin they curve slightly forward. 
The tubercules of the keel stand a little forward of the marginal nodes in a 
position to meet exactly the forward curving of the ribs. 

This, together with the following species, appears to be 
referable to the genus Barroisiceras Gross. It seems to 
have no close ally either in the deposits of Southern India 
or in the Interior Basin of the United States. 

66. Schloenbachia knighteni, sp. nov. 

Plate I, Figs. 1-4; Plate II, Figs. 39-40. 

Shell discoidal, compressed; sides flattened in young adult smaller coils, 
but becoming more inflated in old age, attaining a diameter of 10 cm. ; surface 
characterized by the possession of about thirty simple and almost straight ribs, 
most of which originate at the umbilical margin of tlie whorl; one-third of the 
whole number beginning there in prominent tubercules, the others arising 


below this line upon the sides of the whorl, but all extending to ventral mar- 
gin, where they terminate in equally prominent tubercules. This outer row 
of tubercules shows a tendency to doubling, which can be detected upon all 
shells above a diameter of 1.5 cm., though shown most clearly upon coils 
above a diameter of 4 cm. and below 7 cm. The ribs bend more obliquely 
forward at the inner node of this double row, which is considerably less con- 
spicuous than the outer one. 

The ventral and dorsal margins have an abrupt truncation at maturity, and 
above a diameter of 2 cm., but lose this character and become rounded in 
old age, as they are in the very young stages. 

The keel and ribs seem to appear together just below the diarneter of 
3 mm., the ribs appearing first in the ventral region. The keel,. which is at 
first simple, begins to show crenulations at a diameter of 1.5 cm.,, which 
gradually increase in prominence until maturity. In the older portions of the 
shell these again decline. ■ ;,• 

The umbilicus of this shell is wide and shallow, occupying about one-third 
of the entire diameter of the coil. Within the umbiHcus the thin, sharp ribs 
and dorsal tubercules of the younger whorls are noticeable. 

The sutures consist of a ventral and one lateral lobe, supplemented by two 
auxiliary lobes near and within the umbilicus. The saddles show a tendency 
to become bifid, though this division has actually been seen on only the first 
lateral saddle. Tlie lateral lobe is simple and elongated, with relatively small 
subdivisions, amounting merely to short teeth. 

The name, S. knighteni, is proposed in recognition of 
the kindly interest taken in this study by Mr. E, Knighten 
Anderson, from whose property the larger part of this inter- 
esting collection was obtained, and to whom the author is 
indebted for first calling his attention to this important 

The type is in the collections of the California Academy 
of Sciences. 

67. Schlcenbachia multicosta, sp. nov. 

Plate II, Figs. 41-47. 

Shell discoidal and compressed, umbilicus wide and shallow; moderately 
involute, the outer whorl embracing about one-third, or less, of the inner 
one; sides of whorl flattened, giving a narrow quadrangular outline to the 
shell when viewed from behind; the sides ornamented with about fifty 
oblique, flexuous ribs, which tend to bifurcate from tubercules occurring along 
the inner margin of the whorl. The ribs curve forward in approaching the 
outer margin of the whorl, and like the preceding species this one has a 
double row of inconspicuous tubercules upon the ventral shoulders. The 
ribs are generally rounded; the keel, which is simple and entire, lacks the 


grooves noticed in the preceding species. In development this species is 
very similar to the preceding, but differs from it considerably in the adult 
shells. The essential differences are: (i) the narrower umbilicus of S. inulti- 
costa; (2) the fle.KUous ribs, which have a greater tendency to form tuber- 
cules upon the umbilical shoulders from which bifurcate the ribs; and 
(3) the absence of the grooves along the sides of the keel. The whorls are, 
furthermore, usually inflated in the younger forms. 

Occurrence. — This species occurs abundantly at the 
Smith Ranch, about two miles west of Phoenix, Oregon. 
The horizon is that of the Forty-nine Mine, and is 
the equivalent of the Lower Chico of the Sacramento 

The types are in the collections of the California 
Academy of Sciences. 

68. Schloenbachia bakeri, sp. nov. 

Plate II, Figs. 26-33. 

Shell discoidal, compressed, quadrilateral in section; umbilicus wide and 
shallow, with rounded sides; keel prominent and entire, with slight grooves 
along the sides; involution covering about one-third the inner whorl; sides 
ornamented by about thirty-eight to forty-four simple, oblique ribs, which 
are narrow and sharply angular, each extending from the inner margin of the 
whorl to the keel. 

The ribs form only small tubercules upon the umbilical margin of the 
whorl, though a few of them become a little more prominent here, while 
near the periphery a double row of inconspicuous nodes occurs. The ribs 
bend sharply forward as they approach the keel, while seen from the side 
they appear straight for the greater part of their length. They begin to 
form uniformly at 3>^ whorls at a diameter of 3 mm. 

Keel high and thin, with only faint undulations along its summit, some- 
times not to be seen at all. The smallest coils of the shell are smooth, 
without keel, and almost circular in section except for the impressed zone. 
The keel begins to appear upon the third whorl at a diamet«r of between 
2 and 3 mm. 

The diameter of the largest specimen found is a little more than 3 cm., 
and this is probably the average diameter of adult shells. The body- 
chamber occupies about two-thirds of the last whorl. 

Although a number of otherwise perfect specimens of 
this species were found, the suture of an adult shell was 
not seen. As far as could be ascertained, it is similar to 
that of the following species, S. oregonensis, to which it is 


The name proposed for this species is borrowed from 
the frontier history of Southern Oregon, old Fort Baker 
having stood within a short distance of the locahty from 
which the type was collected. 

Occurrence. — This shell is tolerably abundant at the 
locality of the Forty-nine Mine, near Phoenix, Oregon, on 
the horizon of the Lower Chico beds. 

The type is in the collections of the CaHfornia Academy 
of Sciences. 

69. Schloenbachia oregonensis, sp. nov. 

Plate II, Figs. 48-57; Plate VI, Fig. 144; Plate VII, Fig. 149. 

Sehloenbachia oregonensis Anderson (M. S.), J. P. Smith, Jour. Morph., 
Vol. XVI, 1899, p. 10, Pis. A-E. 

Shell discoidal and compressed, increasing in thickness with age; involu- 
tion embracing about tvvo-liflhs of the depth of the whorl; umbilicus wide 
and shallow, with walls not always abrupt; keel reduced, but distinct, gener- 
ally consisting of an obtuse angle surmounted by a low, thin keel, not 
serrated; surface ornamented with about forty-eight to iifty-two simple 
flexuous ribs, usually arising in pairs from the small, rounded, umbilical 
tubercules, and crossing the sides of the whorl obliquely forward. There 
are also a few subordinate ribs that do not extend above the middle of the 
sides. There is a single row of inconspicuous tubercules along the ventral 
margin of the whorl that forms an angle between the flattened sides and 
the beveled ventral surface. On the older shells these tubercules become 
almost obsolete, as they are also upon young shells. Upon approaching 
these tubercules the ribs bend more obliquely forward, and in tlie old shell 
appear to cross the ventral surface, forming on the keel a faint crenulation. 
On coils with a diameter of less than .8 cm. the ribs are not often seen, the 
shell being almost smooth. The keel first makes its appearance, at a 
diameter of.3cm.,as a faint line upon the ventral margin of the whorl. 
The section of the whorl at this diameter is almost circular. The ribbing 
begins with the development of the tubercules upon the outer margin, 
which is followed by the extension of the ribs upward, and later, by the 
appearance of the umbilical row of tubercules and a downward extension of 
the ribs from them. 

The largest example of this species collected has a diameter of 4.3 cm., 
though fragments of still larger coils were found which may belong to it. 

S. oregonensis is related to S. propinqiia Stoliczka, 
though easily separable from it. 

A variety of S. oregonensis, of which a few small speci- 
mens were collected, has considerably finer ribs, the 


number being about seventy-two, most of which belong 
to the secondary class, not passing above the middle of 
the sides. 

Occurrence. — This species was found abundant at both 
the Forty-nine Mine and at Smith's ranch, two miles to 
the northwest, near Phoenix, Oregon. It belongs to a 
horizon equivalent to the Lower Chico of the Sacramento 

The types are in the collections of the California 
Academy of Sciences. 

70. Schlcenbachia propinqua Stol. 

Plate II, Figs. 34-38. 

Ammonites propinqmis Stol., Pal. Ind., Vol. i, p. 53, PI. XXXI. 

The species of Schlcenbachia which is believed to be 
identical with the Indian form agrees so well in its meas- 
urements and surface markings with Stoliczka's figures 
and description, that were it found in the same region there 
would be no hesitation as to its specific determination. In 
sutural features, however, there seems to be a slight dif- 
ference, though not sufficient to warrant a specific dis- 
tinction. The suture represented in the figure is from a 
younger whorl than that of Stoliczka's figure, having a 
diameter of only 3.5 cm. 

The shell is discoidal and flattened at a diameter of 2 or 3 cm., but becomes 
thicker with increasing growth. At the diameter of 4 cm. the section of the 
whorl is elliptical. The ribs of a single whorl number from forty to forty- 
four, showing a tendency to bifurcate a little below the dorsal, or umbilical 
margin. The keel, at first simple, becomes at a diameter of about 2 cm. 
broken up in slight undulations. 

This species is distinguished from 5". oregonensis not only by the smaller 
number of ribs, but by a number of important and minor differences. 
S. oreg07iensis lacks the prominent umbilical tubercules of the former; its 
sides are also more flattened, the keel less conspicuous in older and in 
young shells, and the abdominal area is more angular. Moreover, in 
S. oregoncfisis this abdominal area is distinctly crossed by the ribs at the 
diameter of a little over 3 cm., which does not appear to be the case either 
in Stoliczka's figures or in the specimens from Southern Oregon. The 
sutures show still more important differences, which only a comparison of 
the types or the figures will make apparent. 


In S. oregotiensis the ventral lobe has only slight subdivisions or none; the 
lateral saddles are simple and rounded, the smaller divisions amounting to 
only shallow scallops. The lateral lobe also shows a corresponding sim- 
plicity of detail. This contrasts considerably with the more deeply cut lobes 
and saddles of S. propinqua. 

In S. propinqua the ventral lobe is divided by a siphonal indentation of 
noticeable depth. 

Both of these species appear to belong to Neumayer's 
genus Schloeiibachiu, which probably includes the following 

71. Schloenbachia blanfordiana Stol. (?) 
Plate I, Figs. 5-10. 
Ammomies blanfordianus Stol., Pal. Ind., Vol. I, p. 46, PI. XXVI. 

Among the collections made at the Forty-nine Mine, in 
Southern Oregon, are several specimens of a shell plainly 
of the type of Stoliczka's species, and at least very closely 
related to it, if not identical. 

The shell is fiat and discoidal, with moderately wide umbilicus surrounded 
by about fourteen or more elevated tubercules; sides ornamented with about 
forty ribs, which are clearly distinguishable on shells below a diameter of 
3 cm., but becoming obsolete with age. The sides of the older whorls are 
smooth, with the exception of the tubercules bordering the umbilicus and 
the ventral margin. The ribs when they appear are flexuous, and show on 
one specimen a tendency to form nodes considerably below the umbilical 
row. The shell becomes a little more involute with age and finally clasps 
about one-half of the preceding whorl. The keel is never prominent and 
with increasing growth becomes, at a diameter of 3 cm., undulating and 
apparently obtuse at 4.5 cm., or reduced to an obtuse ventral angle. The 
suture, as far as it can be seen, agrees reasonably well with that of Sto- 
liczka's figure, showing the same general character of lobes and saddles. 

The ribs of the Oregon species seem to become lost at an earlier age than 
in the Indian form, and the number of umbilical tubercules is not so great. 
On the 3'oung shells the ribs first make their appearance at a diameter of 
I cm., beginning at the ventral margin in small tubercules. 

Occurrence. — This shell was found at the Forty-nine 
Mine, near Phoenix, Oregon. It belongs to a horizon 
equivalent to that of the Lower Chico beds of California. 



72. Mortoniceras crenulatum, sp. nov. 
Plate I, Figs. 17-18. 

Shell small, not above a diameter of 5 or 6 cm.; umbilicu.s wide and 
shallow, with rounded and sloping shoulders; section of whorl quadrate, a 
little higher than broad; surface ornamented by strong ribs, inclined forward 
and nearly straight, with broad, round interspaces extending from within 
the umbilicus to the keel; ribs bearing tubercules at the umbilical shoulder 
and at the ventral shoulder, the latter extending laterally into thorn-like 
spines. The keel is not apparently developed on the youngest whorls, 
which are elliptical in section, but becomes visible at a diameter of about 
4 or 5 mm. The keel, at first simple, becomes very soon finely crenulated, 
but apparently not deeply serrate at a diameter of 5 cm. The ahell is 
smooth up to a diameter of 2 or 3 mm. Septa not well shown. 

This shell evidently belongs to Meek's genus Mortoni- 
ceras, but is not closely related to any other found on the 
Pacific Coast. 

Occurrence. — Found in the lowest horizon of the Chico, 
at Willow Creek, Siskiyou County, California. It was 
associated with Trigonia Icana and other forms of the 
Lower Chico below the horizon of Pachydiscus neza- 
b err y anus. 

73. Prionotropis branneri, sp. nov. 
Plate I, Figs. 11-16. 

cf. Prionocyclus woolgari Meek. Geol. Sur. Terr., Vol. IX, p. 455, PI. \'I1. 

Among the species that should be regarded as "repre- 
sentative" from the Interior Basin and the Pacific Border 
none are more worthy of prominence than the above. 

In form and ornamentation P. branneri strongly recalls Meek's species 
from the Upper Missouri, but it is more inflated. 

Shell more or less discoidal, but not compressed; greatest diameter of 
largest specimen found 12 cm., though fragments of larger specimens were 
collected; thickness at this diameter, 3.5 cm. Keel simple at first, appear- 
ing at a diameter of 2 mm., showing faint undulations at i cm., and in old 
age breaking up into a median row of nodes with rounded outline and with 
rounded intervening depressions; umbilicus relatively wide, equal to about 
three-eighths of entire diameter of coil, having abrupt walls, especially at the 
diameter of 3 or 4 cm. Ribs twenty-five in number, simple at first, appearing 
at a diameter of 2 mm. or earlier. At 5 cm. tubercules begin to develop upon 


the external or ventral shoulder of the whorl in a double row; those of the 
inner row have a greater lateral prominence, while the outer incline more 
toward the plane of the keel. In shells of 3 or 4 cm. diameter these tuber- 
cules have often a triangular appearance that is lost in older whorls. The 
umbilical tubercules are more prominent upon alternate ribs, and are thin 
and ridge-like in form. Above a diameter of 3 or 4 cm. the ribs become 
depressed in their middle portion, forming only a bare connection of external 
and umbilical tubercules in old age. 

The suture line is simple; siphonal lobe long and relatively narrow, with 
short, narrow teeth upon the side, parallel and equal; terminal teeth longer 
and divided; first lateral saddle broad, bifid, and having either sharp or 
rounded, small digitations; lateral lobe broad and tapering evenly in general 
outline, indistinctly trifid, having sharp and narrow digitations; second lateral 
saddle liigh and little cleft, scalloped at margin; second lobe and succeeding 
saddle small and narrow. The digitations of the suture are not always 
regular, different septa of the same specimen showing considerable varia- 
tion. On the whole, however, they agree with the septa figured by Meek 
for his species. Meek seems to have noticed in the Dakota types the same 
irregularity. The furrows along the keel of the Oregon type are compara- 
tively shallow, as seen upon the casts. Aside from this there is no other 
difference in the two types, unless it be a little greater thickness for those 
from Oregon. 

Occurrence. — This species was found on the Smith 
ranch, near Phcenix, Oregon, at whi(;h place several good 
specimens were obtained, though from its abundance tiiere 
it should be expected at the other localities. It belongs to 
a horizon equivalent to that of the Lower Chico beds of 
the Sacramento Valley. 

The types are in the collections of the California 
Academy of Sciences. 



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New species in heavy face, synonyms in italics. 

ACANTHOCERAS 39, 40, 58, 60 

cotnpressum 107 

iiianiillare 42. 108 

naviculare 60 

rhotoniagense 58, 107 

spiniferum 109 

ActEEon 42 

Actreonella oviformis 93 

Actpeonina pupoides 75 

Ammonites . . 99 

batesi 84, 85, 87 

hlanfordianus 124 

cnln 84 

chicoensis 116, 117 

dispar 106 

duvalianus 81 

fraternus 102, 103 

incertus 101 

jugalis 80, 99 

kayci 83 

lalidorsatus lOO 

viantelli 108 

ncivberryanus 102 

proftinqUHS 123 

rliotomagensis var. conipressus . 107 

rouyanus 80 

sacya 82 

stoliczkanus 108 

S7iciae>isis 103, 104 

sugata 98 

whitneyi 82, 83 

Auchura 42 

californica 93 

condouiana 76 

Ancyloceras percostatum 41 

reniondi 63 

Archomya undulata 42 

Astarte trapezoidalis 45 

Atresias liratus 45 

Aucella crassicollis 46 

mosquensis 45 

Piochi 46, 51, 52, 66 

Avicula 42 

Baculites chicoensis . . 36, 50, 58, 60, 92 

fairbauksi 60, 74, 92 

vagina 60, 92 

Barroisiceras 119 

Belemnites 40, 45, 46, 63, 66 

impressus 42, 43 

Cardinia 45 

Cerithium 44 

Chione varians 35, 93 

CinuHa obliqua 34, 50 

Coralliochama orcutti 38, 75 

Crioceras latum 42, 43 

percostatum 42, 45 

CucullEca sp 35 

Cucullsea truncata 35, 76 

Cylichna 33 

Desmoceras . . .40, 44, 58, 63, 73, 80, 93 

sp 40 

ashlandicum 61,76,100 

beudanti 42, 63 

breweri 53 

colusaense ... 96 

darwini 51 

dilleri 97 

hoffnianni . . . .40,71,93.94,96, 97 

j'lgalis 71, 99, 100 

latidorsatiis 53 

lecontei 95 

mayorianum 93 

plauulatum 63, 93, 96 

subquadratum 95 

sugatuni 39, 89, 98 

voyi 63, 100 

Diptychoceras Iseve 42 

Douvilliceras maniillare 108 

Rrato veraghoijrensis 75 

I'lxogyra parasitica 35 

Gabbioceras batesi 87 

Goniomya borealis 39 

Gyrodcs expansa 34 

siskiyouensis 75 

Hamotis antiqua 75 

ir'S ■ ;. 75 

lomaensis 75 

Hamites 39,58, 60, 61 

a;quicostatum 90 

artnatutti 40, 89 

cylindraceus 61, 88, 89 

ellipticus 87 

royerianus 88 

phoenixeusis 88 

solanoense 90 

ilaploceras cumshewaense lOl 

Helicancylus oequicostatus . . . . 90, 92 

Ilelicaulax 42 

bicarinata 42 

Helicoceras 39, 60 

indicum 91 

reussianum 60 

Ileteroceras 39 

ceratopse 91 

reussianum 91 

Holcodiscus theoboldianus .... 63, 101 

Homomya concentrica 35 

Hoplites 40, 44, 46 

Hypsipleura 44 

INOCERAMUS 38, 39, 46, 59 

adutica 73 

crippsi 58 

klataatheusis 73 




Inoceramus labiatus 57,58,59,60 

luytiloides 59 

whitneyi 35, 58 

Lima 42 

Liiidigia nodosum 90, 92 

Liocium punctatum 42 

I.ucina colusaensis 45 

Lytoceras 39, 40, 42, 44, 58, 63, 73 

angulatutn 87 

argonautarum 41, 85 

batesi . . . 43, 63, 71, 83, 84, 85, 86, 97 

cala 63, 84 

duvalianuni 81, 82 

jacksonense 82 

iukesi 58 

kayei 61, 83 

sacya 42, 63. 82 

timotheanum 63 

varuna 61 

Mactra ashburueri 74 

gabbiana 74 

Meekia sella 35 

Mitliea grandicosta 42 

Modiola major 45 

Mortoniceras crenulatum 125 

Myoconcha 45 

Nautilus 40, 77, 78 

campbelli 77 

charlottensis 78 

gabbi 77, 78 

kayeanus 77 

pseudo-elegans 77, 78 

suciatinsis 63, 78 

texanus 77 

Nerinea 42 

Nucula truncata 35 


Olcostephanus 40, 44, 46, 66 

traski 42 

Oxytoma mucronata .42 

Pachvdiscus 40, 58, 60 

henleyensis 89, 104 

merriami 103 

newberryanus ... 40, 50, 58, 102, 125 

sacramenticus 105 

suciaensis 50, 58 

Pecten 38 

californicus 75 

complexicosta 45 

operculiformis 40 

Pectuiiculus pacificus 74 

subplanatus 74 

veatchi 35, 36 

Pentacriiius 36 

Perisphinctes 44. 66 

Pholadomya anaana 73, 93 

Phylloceras 40,42,44, 80 

onoense 63, 86 

ramosum 58,61,86, 99 

shastalense 80 

velledse 63 

Placenticeras 40, 59 

californicum 50, 78, 90, 98 

Placenticeras pacificum . -50,79,90, 98 

Pleuromya 42 

Pleuropachydiscus 94 

Plicatula varia 42 

Potamides diadema 42 

Prionocyclus branneri 59 

woolgari 59, 125 

wyomingensis ... 59 

Prionotropis branneri 125 

crenulatum 40 

Protocardium scitulum 39 

Ptychoccras iFqukostatum 90 

Puzosia darvvini loi 


Rhynchonella densleonis 72 

gnathophora 72 

maudensis 72 

whiteana 72 

whitneyi 45 

SCAPHITES 39, 59, 73, 76, 109 

tequalis no 

condoni 40, 111 

var. appressus 112 

gilHsi 39, 59, 110 

inermis 113,115 

klatnathensis 39, 59, 115 

larv;eformis 59, 115 

perrini 114 

roguensis 112 

warren i 59, 110 

Schlcenbachia . . . .39,59,60,73,76,116 

bakeri 121 

blanfordiana 124 

buttensis 116, II8 

chicoensis 58, 116 

gabbi 74,116,117,118,119 

inflata 42, 63, 116 

knighteni 119 

multicosta 120 

oregonensis . . 39, 121, 122, 123, 125 

propinqua 63, 122, 123 

siskiyouensis 119 

varians 118 

Schliiteria 99 

diabloensis 80 

Schizaster lecontei 99 

Solarium wallalaense 38 

Sonneratia stantoni 105 

Stoliczkaia dispar 63, 106 

Tetragonites 84 

Thetis elongata 42 

Trigonarca 35 

Trigonia 37 

Eequicostata 40 

dawsoni 35 

evansana 35, 35, 58 

leana 40, 125 

tryoniaua 58 

Turbo colusaensis 45 

raorganensis 45 

wilburensis 45 

Turnlites 92 

Turritella 35, 38 



Schloenbachia knighteni, sp. nov. 119 

Fig. I. Adult specimen. 

Figs. 2-3. Young shells. 

Fig. 4. Enlarged suture of young shell. 
Schloenbachia blanfordiana ? Stol. 124 

Figs. 5-6. Adult shells. 

Figs. 7-9- Young shells. 

Fig. 10. Very young shell; X2. 
Prionotropis branneri, sp. nov. 125 

Figs. 11-12. Adult shells. 

Figs. 13, 14, 15, 16. Young shells. 
Mortoniccras ctrniilatum, sp. nov. 125 

Figs. 17-18. Ventral and side views of adult shell with spines. 
Schloenbachia siskiyouensis, sp. nov. 119 

Figs. 19-20. Side and front views of adult shells; natural size. 
Schloenbachia chicoensis Trask. 116 

Figs. 21-22. Side and front views of young shells. 

PhdcCalAcad SclS'^ 5eh Bedl.VdlII. 

[Andersdn] Rate I. 


a y 





Schloetibachia chico'ensis Trask. 116 

Figs. 23-24. Mature shells. 

Fig. 25. Suture line of same. 

Schlceiibachia bakeri, sp. nov. 121 

Figs. 26-30. Mature shells. 

Fig. 31. Enlarged view of ventral surface. 

Fig. 32. Young shell. 

Fig. 33. Enlarged suture of young shell. 

Schlcenbachia propinqua Stol. 123 

Figs. 34-35. Mature shells. 

Fig. 36. Suture line of same. 

Figs. 37-38. Young shells. 
Schlcenbachia knighteni, sp. nov. 119 

Figs. 39-40. Young shells. 
Schlcenbachia multicosta, sp. nov. 120 

Figs. 41-43. Young shells. 

Fig. 44. Very young stage. 

Fig. 45. Very young shell; X2. 

Figs. 46-47. Mature shells. 
Schlcenbachia oregojiensis, sp. nov. 122 

Figs. 48-49. Adult shells. 

Figs. 50-54. Young shells. 

Figs. 55-56. Very young shells; X2. 

Fig- 57- Suture of young shell. 

Scaphites condotii, sp. nov. 11 r 

Figs. 58-59. Mature shells. 

Figs. 60-62. Young shells. 

Fig. 63. Suture line. 

Scaphites condoni var. appressus, var. nov. 112 

Figs. 64-65. Mature shells. 

Fig. 66. Young of same. 

Scaphites roguensis, sp. nov. 112 

Fig. 67. Mature shell. 

Figs. 68-70. Young shells of same. 
Scaphites perrini, sp. nov. 114 

Figs. 71-72. Mature shells; X2. 

Fig. 73. Suture of same. 

Phdc.CalAcaD-Sci.3^ 5EH GEOL VULll 

[ANUERSQniPivoi: II 














Scaphites inermis, sp. nov. 113 

Fig. 74. Mature shell. 

Figs. 75-77. Young shells. 
Scaphites klaniathensis, sp. nov. 115 

Figs. 78-79. Mature shells. 

Figs. 80-81. Young of same. 
Hoplites parva, sp. nov. 

Figs. 82-83. Natural size. 

Fig. 84. Suture of same. 

Scaphites gillisi, sp. nov. no 

Fig. 85. Mature shell. 

Figs. 86-87. Young coils. 

Fig. 88. Suture line. 

Desmoceras voyi, sp. nov. 100 

Figs. 89-90. Shell natural size. 
Sonneratia statitoni, sp. nov. 105 

Figs. 91-93. Mature and young shells. 
Desmoceras lecontei, sp. nov. 95 

Figs. 94-95. Adult, but not full grown shell. 
Helicoceras indicitin ? Stol. 9^ 

Figs. 96-97. Coiled portion; X4. 
Desmoceras sugatum Forbes. 98 

Figs. 98-99. Mature shells. 
Heteroceras ceratopse, sp. nov. 91 

Fig. 100. Portion of coil; natural size. 

Fig. loi. Section of same. 
HcH>nites ellipticits, sp. nov. 87 

Fig. 102. Side view; natural size. 

Fig. 103. Section of whorl. 
Hamites phcenixetisis, sp. nov. 88 

Fig. 104. Body chamber; natural size. 
Schl'uteria diabloensis, sp. nov. 80 

Figs. 105-106. Shell natural size. 

Hac.CALAcAn.Sci.3" 5er BeolVdlIL 

[Ai^idehsdn] Plate 111 






^" 9^A -^ 








lilH BBirmK K HTT. ST. 





Desmoceras ashlandicum, sp. nov. 100 

Figs. 107-109. Young adult shells. 
Schloenbachia buitcnsis, sp. nov. 118 

Fig. no. Full grown shell. 

Fig. III. Section of whorl. 

Phylloceras shastalense, sp. nov. 80 

Figs. 1 1 2-1 13. Mature shells. 

Figs. 114-115. Younger shells. 
Desmoceras dilleri, sp. nov. 97 

Figs. 116-117. Mature shells. 
Desmoceras subquadratuin, sp. nov. 96 

Figs. 118-119. Young adult shells. 

Prdc.CalAcad Sci.3? 5ER.GEaL.VaLn. 

[Anderson] Fute IV 




V _ 100 ^- 


-*T tt "m 

W i ^\'f 

■mt iwnnm * wrf. (U; 



Desmoceras hoffmanni Gabb, 97 

Figs. 120-121. Young adult shells. 

Figs. 122-123. Younger shells. 
Lytoceras ( Tctraffonites) jacksoncnse, sp. nov 82 

Figs. 124-125. Adult shells, without body-chamber. 
Holcodiscus, cf. H. theobaldiatitis Stol. ioi 

Figs. 126-127. Young adult shells; natural size. 
Desmoceras colusaense, sp. nov. 96 

Figs. 12S-129. Adult shell; one-half natural size. 
Hamites arinalmn, sp. nov. 89 

Fig. 130. Side view, body-whorl . 

Fig. 131. Ventral surface, showing spines. 

Fig. 132. Cross-section of same. 

Fi=uc.CALAEAD Bci.S? 5eh Beql.VdlIL 

[Andersqm] Rate V 




Pachydiscus sacramenticus, sp. nov. 105 

Fig- 133- Full grown shell. 

Fig. 134. Young shell. 
Pachydiscus merriauii, sp. nov. 103 

Figs. 135-136. Full grown shells. 

Figs. 137-138. Younger coils. 
Lytoceras (Gabbioceras) aiigulatiini (Gaisb's var.), sp. nov. 87 

Fig- 139- Partial restoration of an adult shell. 
Lytoceras rel. duvalianum d'Orb. 81 

Figs. 140-143. Partly grown shells. 
Schlcenbachia oregonefisis, sp. nov. 122 

Fig. 144. Cross-section of whorls; 22.25 mm. diameter. 
After J. P. Smith. 

FRDC CALAnAE. Bci 3^ 5eh Geol VdlII. 

^Andekuun] PlkteVI 





Lytoceras iimotheaniun IMayor. 63 

Figs. 145-148. Young adult shells. 
Schlcenbachia oregoncnsts, sp. nov. 122 

Fig. 149. Very young shell; diameter 5.6 mm. 

Fig. 150. Very young shell; diameter 1.65 mm. 
After J. P. Smith. 
( For cross-section see Fig. 144, Plate VI.) 
Pholadomya anadna, sp. nov. 73 

Fig. 151. Shell; natural size. 
Baculiles fairbanksi, sp. nov. 92 

Fig. 152. Adult; natural size. 

Fig. 153. Cross-section of same. 
Lytoceras argonautaruin, sp. nov. 85 

Figs. 154-155. Young shells; two-thirds natural size. 
Mactra gabbiana, sp. nov. 74 

Fig. 156. Shell; natural size. 
Rhynchonella densleonis, sp. nov. 72 

Figs. 157-158. Top and front views. 
Pedunculus pacificus, sp. nov. 74 

Fig- 159- Shell; natural size. 
Rhyfichonclla whifeana, sp. nov. 72 

Figs. 160-161. Top and front views; natural size. 

v\LAn bCI.J" ^t: 





Placenticeras pacificum Smith. 79 

(After J. P. Smith, Proc. Cal. Acad. Sci., 3d Ser., Geol., 
Vol. I, Plate XXV.) 
Figs. 162-163. Four coils; diameter 20.5 mm.; X2.7. Ar- 
royo del Vall(5, Alameda County, California. 
Fig. 164. Four and five-sixths coils; diameter 47 mm.; 

natural size. Henley, California. 
Pachydiscus hetileyetisis, sp. nov. 104 

Fig. 165. Section of whorl reduced, at fourteen inches. 
Fig. 166. Section of whorl at a diameter of three and one-half 
Gyrodes siskiyouensis, sp. nov. 76 

Fig. 167. Front view; natural size. 
Fig. 168. Top view of same. 
Belemnites, sp. Texas Flat, Shasta County, California. 40 

Fig. 169. Shell partly restored; natural size. 
Fig. 170. Enlarged view, showing protoconch. 
Placenticeras pacificum Smith. 79 

Figs. 171-172. Adolescent stage; two and five-sixteenths coil; 
diameter 2.32 mm. ; Xio. Henley, California. 
Placejiticeras cali/ortiicum, sp. nov. 78 

(After J. P. Smith, Proc. Cal. Acad. Sci., 3d Ser. Geol., 
Vol. I, Plate XXV.) 
Fig. 173. Three coils; diameter 8 mm.; X2.7. Henley, 

Figs. 174-175. Adolescent stage; three and five-eighths coils; 
diameter 14 mm. ; X2. Henley, California. 
Figs. 176-177. Adolescent stage; four coils; diameter 22 mm.; 
X2. Arroyo del Vall6, Alameda County, 
Fig. 178. Four and one-half coils; diameter 34.5 mm.; 

X2. Henley, California. 
Anchura cotidojiiana , sp. nov. 76 

Fig- 179- Full grown shell; natural size. 




-/■'»'■'■ ■■'■ 

r- A 




n > 



Placenticeras pacificnm Smith. 79 

(After J. P. Smith, Proc. Cal. Acad. Sci., 3d Ser., Geol., 
Vol. I, Plate XXVI; figure redrawn.) 
Fig. 180. Adult shell, diameter 172 mm., six and one-sixth 
coils; natural size. Henley, California. 
Erato veraghoorensis (?) Stol. 75 

Figs. i8r-i82. Shell, natural size. 
Haliods lomacttsis, sp. nov. 75 

Fig. 183. Shell; natural size. 
Hamites ( Ptyclioceras) sola7to'ensc, sp. nov. 90 

Fig. 184. Rear view of body-chamber; natural size. 
Inoceramus klamaihensis, sp. nov. 73 

Fig. 185. View of left valve. 
Fig. 186. Left valve with hinge; natural size. 
Acanthoceras compresstim, sp. nov. 107 

Fig. 187. Shell; natural size. 
Inoceravms adimca, sp. nov. 73 

Figs. 188-189. Front and rear views of adult shell. 

■ K UtUL V2_U. 





































Suture lines of new species. 


Desmoceras lecontei. 95 

Hamiles cUipticus. ^7 

Desmoceras dilleri. 97 

Desmoceras subquadratum. 96 

Bacidites fairbanksi. 92 

Pachydiscus sacramcnticus. 105 

Desmoceras ashlatidiciim. 100 

Holcodiscus, cf. H. theobaldia^ius. loi 

Sonneratia stantoni. 105 

SchliUeria diablocnsis. 80 

Desmoceras colusacnse. 96 

Hcteroceras ceratopse. 9' 

Prionotropis bramieri. 125 

Desmoceras hoffmanni. 94 

FHDC CalAcad Sci 3^ SehGedlVdlII 

IAnhehsdm] Piate X. 




Schlosnbachia oregonensis, sp. nov. 122 

After J. P. Smith, Journ. Morph. Vol. XVL 1899, Plates A and B. 

Figs. 204-206. Protoconch, phylembryonic to ananepionic. Y- 

Figs. 207-208. Phylembryonic to paranepionic; diameter 0.58 mm.; 
one-half whorl, first eight septa, glyphioceran stage 
at the sixth. V. 

Fig. 209. Paranepionic, glyphioceran substage; diameter 0.64 

mm.; third to tenth septa, five -eighths of a 
whorl. Y- 

Figs. 210-211. Phylembryonic to paranepionic, glyphioceran sub- 
stage; diameter 0.68 mm.; three-quarters of a 
whorl, nine septa, 'j . 

Figs. 212-213. Paranepionic, paralegoceran substage; diameter 2.25 
mm.; two and three-eighths whorls, --f. 

Figs. 214-215. Ananeanic, Parastyrites stage; diameter 3.70 mm.; 
three and one-fourth whorls, j'. 

Fig. 216. Paranepionic, glyphioceran substage; diameter 0.74 

mm.; seven-eighths of a whorl. \". 

Figs. 217-218. Paranepionic, transition from glyphioceran to gastrio- 
ceran substages; diameter 1.20 mm.; one and 
three-eighths whorls, y. 

Figs. 219-220. Paranepionic, transition from glyphioceran to gastrio- 
ceran substage; diameter 1.33 mm.; one and five- 
eighths whorls. Y- 
Paranepionic, gastrioceran substage; diameter T.65 

mm.; one and seven-eighths whorls. Y- 
Ananeanic, Styrites stage; diameter 3. 10 mm. ; two and 

seven-eighths whorls. Y^- 
Metaneanic, advanced adolescent stage; diameter 
5.60 mm.; three and three-quarters whorls, show- 
beginning of ribs at a diameter of 4.70 mm. Y- 







Fig. : 


Fedc.QalAcad, Bci.3^ See, Gedl VdlII. 





The Development of B acuities chicoensis Trask.' 

Upper cretaceous, Chico beds, Jordan ranch, Arroyo del 
Vall6, eight miles southeast of Livermore, Alameda County, 

Fig. 226. Protoconch, front view, diameter 0.48 mm. ; enlarged 

15 times. 
First septum, showing siphonal caecum. 
Second septum, at diameter 0.58 mm. 
Larval shell, at one-fourth of a revolution, diameter 

0.58 mm.; 15 times enlarged. 
Sixth septum, at one-half revolution. 
Larval shell, showing the embryonic constriction, and 

the first larval body-chamber; 15 times enlarged. 
Larval shell at three-quarters of a revolution, diameter 

0.83 mm.; enlarged 15 times. 
Larval shell, showing the ornamentation of the embry- 
onic and early larval stage, and the ananepionic 

body-chamber; enlarged 15 times. 
Shell at end of the second larval stage, diameter 1.6 

mm.; 15 times enlarged. 
Larval shell, showing the periodic swelling of the 

siphuncle. Diameter i.oomm.; enlarged 15 times. 
Figs. 239-240. Early adolescent stage, showing the unsynimetric 

shape of the larval coil, and the contraction of the 

shell at the beginning of this stage; enlarged 15 

Fig. 241. Composite drawing from several specimens, showing 

the development of the septa from the embryonic 

into the adolescent stage; enlarged 5 times. 

' These drawings are copied from a paper by J. P. Smith, "The Larval Coil of 
Baculites," American Naturalist , Vol. XXXV, p. 39, Jan., 1901. The numbers on this 
plate do not correspond to the originals of Smith's plates, since not all his figures are 
reproduced here. 




















■ L_l *J X J., 

:j x'lAT^ 







/'' o 








iiEH-BHirraK K hey, bt. 


Third Series. 

Vol. I. 

No. I— The Geology of Santa Catalina Island. By William Sidney 

Tangier Smith j .50 

No. 2— The Submerged Valleys of the Coast of California, U. S. A. , 

and of Lower California, Mexico. By George Davidson . . .50 
No. 3— The Development of Glypliioceras and the Phylogeny of the 

Glyphioceratidse. By James Perrin Smith 35 

No. 4— The Development of Lytoceras and Phylloceras. By James 

Perrin Smith 35 

No. 5— The Tertiary Sea-Urchins of Middle California. By John ^ 

C. Merriam \ 

No. 6— The Fauna of the Sooke Beds of Vancouver Island. By ( ^ 

John C. Merriam ' 

No. 7— The Development and Phylogeny of Placenticeras. By James 

Perrin Smith 50 

No. 8 — Foraminifera from the Tertiary of California. By Frederick 

Chapman 2,5 

No. 9— The Pleistocene Geology of the South Central Sierra Nevada 

with Especial Reference to the Origin of Yosemite Valley. 

By Henry Ward Turner 50 

Vol. II 

No. I— Cretaceous Deposits of the Pacific Coast. By Frank M. 

Anderson 5i • 75 

All subscriptions, applications for exchanges, and inquiries concerning the 
publications should be addressed to 

The Corresponding Secretary, 

California Academy of Sciences, 

San Francisco, California 




Third Series 

Geology Vol. II, No. 2 

A Stratigraphic Study 

in the 

Mount Diablo Range of California 


Frank M. Anderson 

Curator of the Department of Invertebrate Paleontology 

» With Twenty-three Plates 

Issued December 4, igo^ 


Published by the Academy 



Leverett Mills Loomis, Chairman 
Alphkus Bull Joseph W. Hobson 





Third Series 
Geology Vol. II, No. 2 

Issued December 4, igo^ 


Curator of the Department of Invertebrate Paleontology 


Plates'XIII-XXXV p^^^ 

Preface 156 

Introduction 157 

Divisions of the Mount Diablo Range 158 

Stratigraphic Series 159 

Franciscan and Associated Rocks 159 

Cretaceous Strata 160 

Eocene Formations 162 

Miocene Formations 168 

Later Neocene Beds 173 

Coalinga Beds 174 

Etch egom Beds 178 

Etchegoin Sands 178 

San foaquin Clays 181 

Tulare Formation 181 

Stratigraphic Relations 182 

Other Occurrences of Lower Miocene within the Interior 

Basin 186 

San Emidio Section 186 

Beds of the Carisa Ranch 186 

Kern River Beds 187 

Correlations 188 

Conclusions 190 

Descriptions of Species 191 

[i] November 2S, 1905 



The systematic study of the field covered by this paper, 
and its stratigraphy, was begun for purely economic and 
private purposes and not for publication; nevertheless, so 
much data and material of a scientific interest have been 
gathered, and so much information has been acquired, part 
of which, though of a practical nature, it is permissible to 
make public, that some of the more general facts are here 
offered as a contribution to the geological literature of Cali- 

The matter and conclusions set forth are the result of a 
field-study extending over a period of more than two years, 
made partly alone, and partly with the cooperation and aid 
of Mr. Josiah Owen, whose knowledge of the field is both 
extensive and practical to a high degree, and to whom are 
due many of the stratigraphic observations here presented. 

The advantages for a statigraphic and faunal study offered 
by this field are in most respects unsurpassed anywhere. 
The aridity of the climate, and the soft and crumbling 
nature of the younger sediments, together with the action of 
the wind, combine to give excellent and accessible exposures 
of rock, while in many cases the almost perfect preservation 
of the shells and other fossils renders the task of identifica- 
tion satisfactory. The structure of the rocks, moreover, is 
generally simple, and strata are readily followed to almost 
any extent, particularly along the eastern flanks of the range, 
to which most of the field-work was naturally confined. 

In this connection it is proper to mention the generous 
interest taken in this work by Professor E. T. Dumble and 
the many facilities afforded through his kind cooperation. 

The fossils collected during the field explorations, aggre- 
gating several thousand in number, were donated to, and 
have become the property of the California Academy of 



In order that one of the main purposes of this paper may 
be understood, it is necessary, at the outset, to make the 
following statement. It is believed that during the Neocene 
periods, if not throughout the Tertiary, there were a number 
of more or less separated basins, or minor faunal provinces, 
along the Pacific border, two of which are represented 
within the confines of California. 

The California interior basin was bounded approximately 
by the outer Coast Range, the Tehachapi Range, and the 
Sierra Nevada. At the south the barrier described a broad 
curve, following the axis of the Santa Cruz and Santa Lucia 
ranges along the present coast, thence turning eastward to 
Pine Mountain and the Tehachapi Range, which united it to 
the Sierra Nevada. The interior basin thus occupied the 
region of the Great Valley of California and the inter- 
montane valleys between that and the coast. 

The basin thus bounded and outlined is clearly distin- 
guished from that of the open ocean of the time, the littoral 
deposits of which form a narrow fringe at intervals along the 
present coast, or fill the narrow coastal valleys, especially 
at the south. 

The present paper is concerned especially with the deposits 
of the interior basin of California, which are believed to be 
typically represented in the Mount Diablo Range and in a 
few other localities within the Great Valley. 

The Mount Diablo Range, as defined by Whitney,' 
extends along the southwestern border of the Great Valley 
of California, from Mount Diablo, near the Straits of Car- 
quinez, southeasterly to Pine Mountain, where it unites with 
the Tehachapi Range, which links it with the Sierras. Thus 
the valley of the San Joaquin is surrounded by a continuous 
barrier of ranges on the east, south, and west, while it is 
separated by the Mount Diablo Range from the rest of the 
interior basin occupied by the Salinas and the Carisa valleys. 
In other words the Mount Diablo Range divides the basin of 

1 Geo!. Surv. Calif. Geol. v. i, pp. 8-60. 


the California interior somewhat centrally, presenting at the 
same time magnificent stratigraphic sections that are unsur- 
passed anywhere in the West in their exposures. 

Divisions of the Mount Diablo Range. 

Whitney divided the Mount Diablo Range into six more or 
less distinct sections separated by certain low passes, some 
of which at least are notable breaks in the range, and 
though the region was not so well known then as now, it is 
still useful to observe some of these divisions. 

The San Carlos Division of Whitney embraced that 
portion of the range between the Panoche Pass on the 
north and the Estrella (or Cottonwood) Pass on the south, 
thus including most of the western border of Kings and 
Fresno counties, or the territory adjacent to the Devil's Den, 
Coalinga, and "Oil City" petroleum districts. It is this 
division of the range which is chiefly the subject of the 
present paper, the various features of which will serve to 
illustrate the facts and conditions prevailing throughout the 

Rocks of various kinds are found among the formations of 
this section ranging in age from Paleozoic to Recent, and 
embracing both sedimentary and igneous elements, though 
the latter are of only minor importance. For the most part 
the formations are arranged in roughly concentric fashion 
about the two principal centers of this division, one of which 
lies to the south and the other to the northwest of the 
Coalinga district. On the eastern slope of the range the 
structure is usually monoclinal, the strata dipping at varying 
angles toward the Great Valley, generally toward the east or 
north. The Cretaceous and early Tertiary beds stand at a 
high angle, while the younger strata often have a much 
ijentler inclination. 

The general topographic features of the Mount Carlos 
Division of the range are similar to those of other portions, 
and vary according to the underlying formations. The con- 
centric arrangement of the rocks above referred to gives rise 
to similarlv concentric series of hills and dales that have 


developed in accordance with the character and hardness of 
the rocks affected. The higher portions of the range are 
rocky and i-ugged, while the lower eastern slopes are often 
formed of gently undulating hills extending in parallel ranks 
and gradually sinking below the plain to the eastward. 

The principal streams of this section, flowing toward the 
Great Valley, are the Panoche, San Carlos, Cantua, Los 
Gatos, and Alcalde creeks, each of which cuts deep can- 
yons into the softer formations near the valley, but heads 
high up on the rocky ridges in the central parts of the 
range. Farther south are the Sunflower and Antelope 
valleys with converging streams. 

Stratigraphic Series. 
Franciscan and Associated Rocks. 

The oldest rocks met with in the San Carlos Division of 
the range are those generally referred to the Franciscan 
series, including not only the well known sedimentary fac- 
tors, but also certain basaltic and other igneous rocks closely 
connected or involved with them. It is perhaps sufficient to 
say that the entire series, including the eruptives, are in point of 
age pre-Cretaceous, though they have been variously assigned 
by different authors, wholly or in part, to the Paleozoic, 
Jurassic, or Cretaceous periods. 

The sedimentary members of the Franciscan series repre- 
sented in this field include the rocks ordinarily found asso- 
ciated in this formation, such as radiolarian jaspers, sand- 
stones, slates, and schists, and perhaps certain conglomerates. 

Closely connected with the Franciscan rocks territorially 
are the serpentines of the range. While it is not likely that 
the connection is anything more than territorial, as in point 
of age the serpentines are of more recent origin and there- 
fore more closely connected with the succeeding series, still, 
as their association with the Franciscan rocks is habitual 
even outside this district, they may be better classed with 
these than with any other formations. 


The geologic and topographic features of the series are 
the same as everywhere in the coast ranges both north and 
south of the Bay of San Francisco. In this field the series 
is confined in its occurrence to the axis of the chief range 
extending west of the Coalinga district, or, more accurately, 
to a few prominent areas within that range. 

There are two or three principal areas of Franciscan and 
serpentine rocks, separated to a considerable extent by an 
area of Cretaceous strata. One of these lies to the south of 
the upper tributaries of Alcalde Creek (or Warthan Canyon), 
and extends from there southeasterly to Cottonwood Pass ; 
another extends from the upper branches of Los Gatos Creek 
northward toward the Panoche Valley and the tributaries of 
the San Benito River, and therefore includes the New Idria 
quicksilver district and the San Carlos and San Benito peaks. 

The most extensive formation in this area is undoubtedly 
serpentine. To the south and west of New Idria, serpentine 
is almost the only rock to be seen for many miles. The 
sedimentar}' rocks of the Franciscan series are mostly con- 
fined to the southern and western borders of the area. 

Cretaceous Strata. 

Lying along the eastern margins of the Franciscan areas 
and filling wide spaces between, are Cretaceous rocks, form- 
ing a stratified series of great thickness and dipping steeply 
toward the Great Valley. An important area of Cretaceous 
rocks is that between the Alcalde and Los Gatos creeks near 

The Cretaceous strata include both the Knoxville and 
Chico divisions, with the intervening Horsetown Beds appar- 
ently omitted. The usual nonconformity between these mem- 
bers has not been proved in this field directly, though there 
are abundant grounds for believing that it exists. 

The Knoxville consists of a thick series of dark clay shales 
and thin-bedded sandstones, lying next to the Franciscan 
rocks. They have been particularly noted along the head 
waters of Alcalde Creek, near the Fresno Hot Springs, on 


the head of the Jacalitos Creek, and at the Devil's Den, 
south of the Sunflower Valley. The Cretaceous rocks in 
the vicinity of the New Idria quicksilver mines have long 
been known. From there they extend southeasterly to Coa- 
linga. In the Knoxville portion the only fossils so far dis- 
covered are species of A7ninonites, (^Hoplites), Beleniuites, and 
imperfect plant remains. 

The Chico rocks, which are chiefly in evidence north of 
Alcalde Creek, and still more so north of Los Gatos Creek, 
form a thick series of yellow clay shales and tawny colored 
sandstones. To the north of Los Gatos Creek they extend 
high up on the range and constitute the most conspicuous 
formation of the mountain as seen from the south and east. 
The sandstones predominate, and make up two quite distinct 
members of the upper part of the Chico, with thick beds of 
yellow clay shales between. The upper sands of the Chico 
are characterized by large sandy concretions of a brown 
color, which have a tendency to split horizontally or to fall 
apart in concentric shells or laminae. 

Thus far species of Inoceramus are the only fossils found 
in these concretionary rocks, but Baculites have been found 
in close connection with them near the coal mine west of 
Coalinfja. The concretionarv sandstone has a maximum 
thickness of some four hundred feet where it is exposed nine 
miles north of Coalinga. The yellow shales below the con- 
cretionary sandstones contain masses of nodular limestone 
from which were obtained at different points the following 

Baculites chicoensis Gabb Inoceravius zchitneyi Gabb 

Baculites sp. Perissolax brevirosiHs Gabb 

Lytoceras sacya Forbes Architectonica sp. 

Desmoceras (rel. D. hoffmanfii Gahh) Gyrodcs sp. 

Pectunculus veatchi Gabb Cimilia obliqua Gabb, etc., etc. 

The Chico rocks stand at a high angle all along the range, 
and vary in strike to conform to the underlying Franciscan 
and other rocks. For the most part all the Cretaceous rocks 
strike northwesterly or a little north of west. Perhaps the 
averajje strike of the Cretaceous rocks is N. 60° W. How- 


ever, there are two structural ox-bow curves, one on either 
side of Coalinga at a distance of some ten or more miles, in 
which the Cretaceous rocks are carried well toward the val- 
ley, forming the foundation upon which the Tertiary oil 
yielding strata are deposited. 

Attention should be directed to these curves as structural 
features of the range as a whole, but too little is yet known 
of them to warrant more than a suggestion. It appears that 
their repetition along the eastern part of the range forms the 
axes of local anticlines in the later strata which plunge 
respectively below the level of the valley bottom. No less 
than six such folds are known between the Sunset district 
and the Big Panoche Creek north of Coalinga, but their 
fuller discussion must be left for another time. 

Eocene Formations. 

The Eocene strata of the Coalinga district and vicinity lie 
in detached belts alongr the eastern and northeastern flanks 
of the range. One of the more extensive belts of Eocene 
rocks extends from the northern border of the Sunflower 
Valley westerly to the head of Alcalde Creek. Another 
begins in the hills west of Coalinga and extends northerly 
for two miles or more and includes the coal mines of that 
district. A third belt begins north of Los Gatos Creek, 
extends northeasterly along the foothills, and can be traced 
north and northwesterly in a fairly well marked band for 
twelve or fifteen miles to Salt Creek, and thence westerly 
to Silver Creek and the Panoche Valley. Northward from 
Los Gatos Creek the Eocene forms a fairly uniform and 
continuous series as far as it has been followed. 

Still another area occurs on the northern border of the 
Antelope Valley near the Devil's Den, and includes the 
massive sandstones at the place locally termed the Point of 
Rocks. A fifth and more southerly area of Eocene occurs 
in the near vicinity of Temblor and at Canara Springs and 
northward toward the Antelope Valley. At Canara Springs 
the massive sandstones of the Eocene form conspicuous and 
picturesque cliffs, over which lie the more regular beds of 


the Lower Miocene. These massive sandstones present 
many curious and striking examples of atmospheric erosion, 
among which are the natural cisterns often developed on 
the summits of the most conspicuous pyramids of rock. 

Along the Eocene belt extending westerly from Tar 
Springs the rocks stand at a high angle dipping to the north 
at an angle of 75° to 80°. In the Coalinga belt they likewise 
stand at a high angle dipping toward the east, while farther 
north the inclination is less and the strike carries them in a 
broad curve around the outer flanks of San Benito Mountain. 
The dip naturally varies in its direction with the strike, but 
in its inclination it is commonly between 25° and 35°. 

While the stratigraphic divisions of the Eocene do not 
continue regularly throughout, there is at least one member 
that is fairly well characterized along the whole extent of 
the series as far as followed. This member is the middle 
one, and consists of brown bituminous or carbonaceous 
shale, more or less sandy in the lower portion, and with 
a maximum thickness of six hundred feet as exposed on 
the hills a few miles north of Coalinga. Farther to the 
south and southeast it varies considerably, attaining at the 
Kreyenhagen wells a thickness of about nine hundred feet, 
while on the head of the Jacalitos and on the Zapata Chino 
there are not more than two hundred fifty or three hundred 
feet of strata. On account of its development at the Krey- 
enhagen wells this member of the Eocene has been termed 
the Kreyenhagen Shales. The lithological character of these 
shales is not constant, as the proportions of the chief elements 
vary from point to point. Sands, clay, and organic matter, 
both calcareous and carbonaceous, make up the mass of the 
beds, which at some points become sandy and at others argil- 
laceous, while the percentage of lime or carbonaceous matter 
also varies. 

Nodular masses of calcareous rock and nodules of barites 
( Ba SO4 ) are common in many places, and these form a 
characteristic feature of the shales. 

The calcareous masses occurring in the shales often con- 
tain foraminifera in great numbers, not unlike certain rocks 


of the Miocene. The brown color of these shales is proba- 
bly due in large part to bituminous matter contained therein ; 
but this will be referred to later. 

Both above and below the Kreyenhagen Shales are sands, 
which at some points are sufficiently consolidated to form 
hard rock. 

South of the Kreyenhagen wells there is a great thickness 
of sandstone exposed along the canyon of Canoes Creek with 
a thin basal bed of conglomerate resting upon the Lower 
Cretaceous shales. The strata stand almost vertical with a 
dip of 75° or 80'^ toward the north and an east-west strike. 

At least the upper four hundred feet of this sandstone, 
and possibly all of it, is to be referred to the Eocene. A 
few miles to the east, at Tar Springs, the lower portion of 
the Eocene consists of about four hundred feet of concre- 
tionary sandstones which are very fossiliferous. The con- 
cretions occupy a place immediately below the Kreyenhagen 
Shales, while lower down are thin beds of sandstone, and at 
the base a bed of pebbly conglomerate six to ten feet in 
thickness, resting upon strata of Cretaceous age. The Avenal 
wells at Tar Springs are drilled to penetrate these sands. 
These basal and concretionary sandstones can be followed 
for several miles both east and west from Kreyenhagen's, 
being exposed at Tar Springs on the east and at the Sulphur 
Springs on the Zapata Chino Creek to the west. On account 
of their development at the Avenal wells (Tar Springs) they 
may be conveniently termed the Avenal Sandstones. 

The species of invertebrate fossils obtained from these 
sandstones include the following: 

Cardita horni Gabb ( C. planicosta Architectonica horni Gabb 

Conrad) Ancellaria elongata Gabb 

Cardiiitn cooperi Gabb Dentalium cooperi Gabb 

Cardita sp. Fusus martinez Gabb 

Corbula paratis Gabb Fusus diaboli Gabb 

Solen paratellus Gabb Turritetta uvasana Gabb 

Meretrix horni Gabb Turritetta pacheco'ensis Stanton 

Amauropsis atveata Gabb Neverita gtobosa Gabb 

A stratigraphic section of the rocks at Tar Springs is 
shown in the accompanying sketch (PI. xxxiv, fig. i). 


At the sulphur spring in one of the canyons of Zapata 

Chino Creek the Eocene is represented by the following 

members : 


Kreyenhagen Shales 250 

Avenal Sandstones 500 

Basal conglomerate 15 

It will be seen that the Kreyenhagen Shales are consider- 
ably reduced in thickness while the Avenal Sandstones are 
somewhat thickened, but the latter was proved by the con- 
cretionary masses, by the basal conglomerate, and by fossils. 
The entire series stands at a high angle with a westerly 
strike and a dip to the north. 

The Eocene could not be traced westerly beyond the 
Sulphur Springs on the Jacalitos Creek. 

At the Point of Rocks on the northern border of the Ante- 
lope Valley there are about twenty-four hundred feet of 
Eocene strata exposed, the lowest beds of which contain the 
following species : 

Neverita globosa Spondylus carlo sensis n. sp. 

Turritella uvasana Cardita 

Discoheli.v Terebratella 

Meretrix uvasana Sea urchins 
Ostrea idriaeusis 

These beds dip northeaster^ at an angle of near 30°, and 
to the eastward are overlain by the sandy beds of the Lower 
Miocene. The upper one-third of the Eocene consists of 
sands which include exposures like that shown on Plate xxvii. 
Between the fossiliferous concretionary sandstones forming 
the lowest beds exposed and the massive sand beds above, 
there are softer and less resistant beds that perhaps represent 
the shales which form elsewhere the intermediate member. 

At Temblor and Canara Springs the massive sands are 
exposed, but the shales and fossiliferous beds below were 
not identified. The unconformity of the Lower Miocene 
beds upon these massive sands of the Eocene is well shown 
on Plate xxv. 

In the areas extending northward from Coalinga the 
Avenal Sandstones have been only indirectly proved. At 



the coal mines the basal portion of the Eocene is occupied 

by thin beds of conglomerate, sand, and coal-bearing sandy 

shale. The following stratigraphic section fairly represents 

the Eocene at the coal mines: 


Kreyenhagen Shales 400 

Echinoderm conglomerate 8 

Carbonaceous sands 140 

Two fossil horizons are to be noted in this section: (a) 

that of the pebbly conglomerate containing species of 

Echinoderms; (b) that of the carbonaceous sands. The 

thin bed of conglomerate has afforded the following species : 

Cassidiilus californiciis n. sp. Spondylus carlosetisis n. sp. 

SciUella sp. A. Tellina sp. 

Echinoderms (genus not det.) Galenis excentricus Gabb 

Ostrea aviculiforniis n. sp. Turritella tivasaiia Gabb 

Cardiuni cooperi Gabb Terebratella sp. 

Mactra sp. Crustaceans (Cancer, etc.) 

Meretrix honii Gabb Nodules of barites 

Ostrea (2 sp.) 

From the sandy beds more closely connected with the 

coal and carbonaceous strata were obtained : 

Modiola ornata Gabb Ostrea idriaensis Gabb 

Meretrix uvasana Gabb Limatia horni Gabb 

Meretrix horni Gabb Nerita triangulata Gabb 

Cardium cooperi Gabb Neverita globosa Gabb 

Mactra sp. Galerus excentricus Gabb 

Area ( Barbatia ) inorsei Gabb Fusus niartinez Gabb 

Cardita sp. Turritelta pacheco'ensis Stanton 
Placiianoniia inornata Gabb 

North of Los Gatos Creek a pebbly conglomerate, si.x to 

ten feet thick, near the top of the Kreyenhagen Shales, has 

been followed almost continuously for a distance of four 

miles. It has yielded the following species : 

Ostrea aviculiformis n. sp. Morio tiiberculatiis Gabb 

Cardita horni Gabb Turritella uvasana Gabb 

Dositiia sp. Turritelta pacheco'ensis Stanton 

Gari texta (?) Gabb Trochosmitia striata Gabb 

Cardiuni cooperi Gabb Ellipsosuiilia granulifera Gabb 

Pecten sp. Terebratella sp. 

Meretrix horni Gabb Echinoderms (2 sp. undet.) 

Ostrea (2 sp.) Sharks' teeth 

Spondylus carlosensis n. sp. Teleost. vertebrae 

Amauropsis alveata Gabb Nodules of barites 


On the N. E. ^4^ of Sec. 17, north of Coalinga, similar 
pebbly beds just above the top of the Kreyenhagen Shales 
contain a few of the foregoing species along with species of 
Foraminifera and nodules of barites. 

This horizon of the Eocene begins its greater development 
at this point and increases in thickness as it is followed to the 
northwest. On the east side of Section 17 it has a thickness 
of not more than three hundred fifty feet, while eight miles 
to the northwest it has a thickness of something like twelve 
hundred feet, where it is exposed in the vicinit}' of the Kim- 
ball wells. 

It consists chiefly of yellow sands, which, as far as they 
have been followed, are but little consolidated, and under 
the meager rainfall of the region readily disintegrate, forming 
loose sandy slopes. Its great development in the vicinity of 
the Domijean ranch affords grounds for its designation as 
the Domijean Sands. 

On the west side of Section 17 the sandy beds at the base 
of the Eocene aggregate somewhat more than at the coal 
mine, but they are also more distributed stratigraphically, 
with shales intei"vening between their several layers. 

They are partially represented on Plate xxxiv, figure 3. 
Their correlation with the Avenal Sands is based chiefly 
upon tlieir stratigraphic position, as they are undoubtedly 
basal and rest directlv upon the concretionary Chico sand- 

In the vicinity of New Idria and along the southern side of 
the Big Panoche Valley the Eocene rocks present the stratig- 
raphy characteristic of the series north of Coalinga. Three 
members are clearl}- distinguishable, though their aggregate 
thickness can hardly exceed twelve hundred feet. The beds 
may be divided as follows : 


Loose ash-colored sandstones 300 

Carbonaceous clay shales 300 

Sandstones (ash-colored) 600 

Total 1200 

The Eocene age of these beds appears to have been at 


least suspected by Gabb, as shown in Whitney's' discussion 
of the region. 

The stratigraphic members of the Eocene, then, are the 
following : 

Domijean Sands 

Kreyenhagen Shales 

Avenal Sandstone 

The lack of continuity of these members along the entire 
range is to be attributed partly to their nature and manner of 
origin, and partly to their degradation previous to the laying 
down of the succeeding Miocene or Pliocene strata ; naturally, 
therefore, this lack affects chiefly the lower and upper mem- 
bers, while the intermediate member is more uniform in its 
character and at the same time more persistent in its occur- 

The preceding lists of fossils contain representative Eocene 
species such as indicate that the beds are to be correlated 
rather with the Tejon than with the Martinez division of the 
Eocene, and this accords with the fact that the latter horizon 
has been considered local in its occurrence, or extending 
only northward from the latitude of Mount Diablo, and also 
with the fact that the Tejon Beds are found at New Idria and 
other points only a few miles north of the limits of our own 

Miocene Formations. 

Rocks of the Miocene period do not enter extensively into 
the stratigraphy of the San Carlos Division of the range 
north of Alcalde Creek, but south and east of this stream 
they are more in evidence. Miocene strata occur in some- 
what disconnected belts running parallel with the Eocene, 
and to some extent parallel with the Cretaceous. The 
greatest thickness of Miocene rocks found in any part of the 
range is near McKittrick and Temblor, although thicker 
aggregations of strata are found elsewhere, as on the western 
border of the Carisa Valley. 

1 Geo!. Surv. Calif. Geol. v. i, p. 57. 


The most representative section of the Miocene that has 
been observed anywhere in the range south of the Cantua 
Creek is to be seen at Temblor and Canara Springs in west- 
ern Kern County. Though no detailed study of these strata 
was undertaken, a general statement will be found interesting 
and instructive. The most conspicuous member of the 
Miocene in this section is the Monterey Shales, which have 
here an aggregate thickness of more than five thousand feet. 
For the most part this member consists of light colored 
shaly strata, the material of which is evidently largely 
organic, but in which three or more elements are easily 
recognizable; viz., foraminiferal limestone, siliceous organic 
beds, clay shales, and supposedly volcanic dust and ash. 

The limestone occurs in thin lenticular bands, gray or 
yellowish in color, in which Foraminifera are readily seen 
through a good lens. These yellow or light gray bands 
occur in groups or singly, scattered through the entire 
thickness. The siliceous portion of the Monterey Shales 
predominates, and generally shows remains of Diatomaceae 
and other siliceous organisms, with bones and scales of fishes. 

Near the top of the series the strata become more chalky 
and softer. Pecten peckhami has been found at both the top 
and bottom of this member at Canara Springs and eastward. 
The Monterey Shales, apparently, in undiminished thickness, 
make up the mass of the main range west of McKittrick, 
but they have not been traced easterly much beyond the 
Sunset district. 

Underlying the Monterey Shales at Canara Springs and 
Temblor are sandstones and sandy shales which make up 
an additional thickness of fifteen hundred feet. The entire 
series., of Miocene rocks at this point is about as follows : 


Monterey Shales 5500 

Sandstones with Astrodapsis 100 

Siliceous and clay shales with interstratified sandstone 600 

Sandstones with numerous fossil species 800 

Total thickness 7000 

The sandstone with Astrodapsis contains in addition Pecten 
nevadensis, Pecten discus, and a few fragments of oysters and 


barnacles. The lower fossiliferous sandstones yielded the 
following species of invertebrates : 

Lucina borealis Linn. Pecten sp. 

Lucina richthofeni Gabb Solen sp. 

Yoldia cooperi Gabb Tapes sp. 

Mytilus tnathewsoni Gabb Maconia sp. 

Chione niatheiusoni Gabb Ballauus sp. 

Dosinia mathewsojii (?) Gabb Neverita callosa Gabb 

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 Temblor Beds is suggested to 
embrace this aggregate of strata, while for the first sandy 
beds below the Monterey at Temblor the name " Button 
beds" has been used on account of the great numbers of 
small discoidal sea urchins (^Astrodapsis) which characterize 
them here and elsewhere. 

The Temblor Beds are often characterized by sands, 
more or less distinctly stratified, which are usually rendered 
highly calcareous by great numbers of fossil invertebrates. 
Echinoderms are sometimes so abundant that certain beds 
become almost a limestone. Occasionally pebbly layers are 
encountered, and at other points the sandstones become 
noticeably shaly. 

As will be noticed further on, it is not rarely that the 
Monterey Shales are found resting on older rocks without 
any appearance of the Temblor Beds intervening. In some 
places there is a distinct overlapping of the Monterey Shales 
beyond the borders of the Temblor Beds. 

North of the Canara Springs there is no similar thickness 
of Miocene strata anywhere in the Mount Diablo Range as 
far as known to the writer. In the vicinity of the Devil's 
Den and northward the section is materially reduced, chiefly 
by the reduction of the Monterey Shales. 

Nowhere north of the Antelope Valley have these shales 
been found to exceed one thousand feet in thickness, though 
otherwise they are identical and appear to represent the 
basal portion of the shales occurring in the Canara Springs 


Miocene strata describe a broad curve around the eastern 

side of the Sunflower Valley, but at most points only the 

Monterey Shales are visible. On the northern border of the 

Sunflower Valley, at Tar Springs, the Miocene section is 

about as follows : 


Monterey Shales 900 

Temblor Sandstones with fossils 800 

White sandy shales 400 

Total 2100 

This section is representative of the Miocene occurrences 
at most points between the Antelope Valley and Alcalde 
Creek. The Miocene rocks rest indiscriminately upon the 
Eocene, the Cretaceous, or older rocks as the case may be, 
though not always with an appearance of unconformity. 
The dip is always toward the Great Valley at some angle 
between 20° and 90°. At Tar Springs the dip is above 75°. 
At the Devil's Den on the south side of the Sunflower 
Valley the dip is in some places anticlinal, and to the west of 
the valley the Monterey Shales rise upon the flanks of the 
main range, overlying the Cretaceous without any appear- 
ance of the Temblor Beds. 

The topographic aspect of the Temblor Beds is striking. 
They stand out in bold relief along the whole range from 
McKittrick northwestward to near Coalinga, and form a 
species of serrated wall along the front of the hills through 
which the canyons emerging into the Great Valley have cut 
their ways. This is particularly noticeable along the north- 
ern border of the hills extending west from Tar Springs, and 
in many other parts of the country. This feature is shown 
in some degree on plates xxviii and xxix. 

The following fossil species have been collected from the 
Temblor Beds at different points : 

Tar Springs. 

Sciitella sp. Neverita callosa Gabb 

Astrodapsis nierriami n. sp. Dosinia ^natheivsoni (?) Gabb 

Pecten discus Conrad Crepidiila praerupta Conrad 

Pec ten crassicardo Conrad Ballanus sp. 

Turritella ocoyana Conrad 

[2] November 28, 1905 



Kreyenhagen Wells. 

Astrodapsis nierrianii n. sp. 
Pecten discus Conrad 
Pecten estrellanus Conrad 
Turritella ocoyana Conrad 
Agasoma graviduni Gabb 
Neverita callosa Gabb 
Mactra densata Conrad 
Venus {Chione) tanblorensis n. sp. 
(rel. C. guidia.) 

Zirphaea sp. 

Natica sp. 

Mactra {Spisula) sp. 

Ostrea sp. 

Hemifiisus wilkesana n. sp. 

Lticina acutilmeaia Conrad 

Area moiitereyana Osmont 

Balla?ius sp. 

Sulphur Springs, Zapata Chino Creek. 

Mactra densata Conrad 
Mactra sp. 

Area montereyana Osmont 
Tapes sp. 

Lucina sp. 

Venus ( Chione) temblorensisn. sp. 

Astrodapsis merriami n. sp. 

The species given in the preceding lists are characteristic 
of the Lower. Miocene as it occurs in the Great Valley of 
California, and perhaps that of all the interior valleys of the 

The more northerl}^ belt of Miocene rocks in the Coalinga 
district begins a few miles to the northwest of Coalinga, on 
the north side of Sec. 2, T. 20 S., R. 14 E., and extends in 
a broad curve northeasterly, northerly, and northwesterly for 
many miles, or quite beyond the Cantua Creek. 

It is fairly well shown on the Coalinga geologic map pre- 
pared for this paper (PL xxxv). The dip of the strata is 
always toward the Great Valley at angles varying from 20° 
to 35°, and in directions normal to the strike. In a few cases 
only, and notably in one or two cases, is the structure com- 
plicated. In the main the structure of all the Tertiar}^ rocks 
is monoclinal. But on the S. E. % of Sec. 20, T. 19 S., 
R. 15 E,, the Miocene rocks are exceedingly crushed and 
distorted by compression, and to some extent this distortion 
extends also to the Eocene and the Pliocene rocks. 

Two members of the Miocene have been detected in the 
Coalinga district proper, but possibly others occur a few 
miles to the northwest. For the most part the Temblor Beds 
are not present, and the following members only are in 


evidence, as in the vicinity of the Kimball wells, where the 
following members occur: 


(?) Contra Costa Beds 

Monterey Shales 800 

Domijean Sands (Eocene) 1200 

Ashy beds near the top of the jNIiocene resemble both litho- 
logicall}' and faunally beds on the baj^-shore north of Pinole 
Station, Contra Costa County. The following species were 
collected from these Miocene beds on the west side of Sec. 19, 
T. 18 S., R. 14 E.: 

Ashy beds. ]Monterey Shales. 

Leda oregona (?) Pecten peckhaini Gabb 

Tellina congesta ( ?) Callista ( ?) sp. 

The Miocene rocks show little evidence of beincf bitu- 
minous as they are followed northward toward the Cantua 
Creek, and in fact there is but slight direct evidence that 
they are bituminous at any point between Coalinga and the 

The noteworth}- facts about the Miocene series north of 
Coalinga as far as followed are the absence of the Temblor 
Beds and the greatly reduced thickness of the Monterey 
Shales. Strata of apparently the horizon of the Temblor 
Beds occur in the Walnut Creek Valle}' west of Mount 
Diablo, as described by Dr. Merriam.^ 

Later Neocene Beds. 

By far the most important series of strata in the Mount 
Diablo Range from the view-point of economic geology are 
the late Tertiary strata, including the probable equivalents of 
the San Pablo Beds and others with which they are uncon- 
form.ably related. In this collection of strata the following 
members are distinguishable, either stratigraphically or fau- 
nally : 

1 Bull. Dept. Geol. Univ. Calif, v. 3, pp. 377-381. 


Etchegoin Beds j San Joaquin Clays 

(San Pablo Beds ?) I Etchegoin Sands 

Coalinga Beds \ Oyster Sands, etc. 

( Reef Beds, etc. 

Each of these divisions could be again subdivided with 
greater or less success w^ithin specified limits, but it would be 
difficult to discover features characteristic enough for such 
purposes that would have a wide application. In other words, 
the materials of the strata change more or less from point to 
point along their strike, passing from coarser to finer, etc., 
according to local conditions during the period of their depo- 
sition, such as the presence of streams, currents, etc. 

The most constant feature of the lower two-thirds of the 
combined series is its sandy character, while the upper por- 
tion is clay or fine sand and clay, in which the clays are 
variegated in color, being alternately white, red, gray, or 

Co a Ibiga Beds . 

An interesting stratigraphic unit is that here described 
as the Coalinga Beds. So far they have been found only 
locally, and throughout a stretch of more than fifty miles 
along the Mount Diablo Range they were not recognized 
at all. They occur, however, in both the Coalinga and 
McKittrick districts, and in each case sufficiently individual- 
ized to be regarded as distinct from both the Monterey and 
the Etchegoin Beds. 

In the Coalinga district, as shown on the map (PL xxxv), 
the formation occurs in two separate areas, the more north- 
ern of which can be followed far beyond the limits of the 
map, or at least to the Cantua Creek if not to Mount Diablo. 

West of Coalinga these beds are sandy with a minor part 
of shale, which at one place north of the coal mine appears 
to be soft and marly if not diatomaceous. At the artesian 
water well on Section 35 these marly beds do not appear, 
but the basal beds are composed of sands which are locally 
bituminous. Six miles north, on the E. J^ of Sec. 36 marly 
beds crop out very near the base and present also a strongly 



bituminous appearance in their yellow red, and brown dis- 
colorations. The stratigraphic position of these white marly 
beds can be well observed at many points, as on the south 
side of Sec. 20, T. 19 S., R. 15 E., where a conspicuous 
reef of sandstone crosses the ravine, with marly beds both 
above and below. This sandy stratum, on account of its dis- 
position to protrude here into a sort of wall, and from the 
fact of its being fossiliferous, was during our field-study 
termed the J^eef Bed, and it proved a useful name in further 
exploration. The accompanying sections show the principal 
stratigraphic features of the Coalinga Beds at two or more 



Yellow sands, etc 1300 

Tamiosoma Bed with oysters, pectens, etc... 20 

Yellow sands 550 

White shale (marly) 20 

Dark sands 50 

Reef Bed 40 

White shale with oysters 20 

Basal sands, etc 180 

Coalinga Beds ten miles 
north of Coalinara 

Coalinga Beds twenty 
miles northwest of - 

Coalinga Beds three 
miles west of Coal- 

Yellow sands 1000 

Sands with oysters 6 

Sandy white shales 80 

Tamiosoma Bed with oysters, pectens, etc... 15 

Yellowish sands, gravels, etc 320 

Reef Bed (sandy) 15 

Basal sands and conglomerate 120 

Blue sands, gravels, etc 2400 

Pecten beds 40 

Sands, gravels, etc 700 

Sands and yellow gravels 1000 

Dark sands with Diplodonta harfordi. 50 

Reef Bed (sand stone) 50 

Gray sands, unconsolidated 200 

1 Basal gravels 50 

It will be seen by an inspection of these sections that there 
is throughout the field but little continuity to any of the litho- 
logic features that seem locally to be significant, as gravels 
give place to sands, and both become locally calcareous, or 
the reverse. 

A somewhat more satisfactory means of correlating or 
identifying strata is found in the faunal contents as illustrated 


in the case of the Reef Bed, from which the following species 
have been obtained where the bed can be traced continuously 
for two or three miles through Sec. 16, 21, and 20; T. 19 S., 
R. 15 E. 

Reef Bed, Sec. 20 and Sec. 21 : 

'^ Astrodapsis iumidus Reniond * Tapes tenerrima Cpr. 
*Arca montereyana (?) Osmont Lucina borealis Linn. 

* Dosinia ponderosa Gabb *Pseudocardium sp. 
*Mactra {Spisula)/a/cata (?) Gould *Neverita recluziana Desh. 

Macoma inquinafa (?) Desh. Hemifusus sp. 

Mvtilus californianus Conrad * Trophon gabbiana n. sp. 
*Pecten discus Conrad Trochita sp. 

Pec ten estrellanus Conrad Sharks' teeth 

The more characteristic of these species were found in the 
Reef Bed of Sec. 20, T. 18 S., R. 14 E., including: 

*Pectefi discus Conrad * Dosinia po?iderosa Gabb 

* Astrodapsis Iumidus Remond 

A Stratum in the last section immediately above the white 
shales, four hundred feet above the Reef Bed, contained the 
following species and genera : 

Cytherea ( Callista) sp. Soleti sp. 

Chione (rel. C. guidia) Ostrea sp. 

Macoma nasuta Cpr. Agasoma kernianum Cooper 

Pecten estrellanus Conrad Turritella sp. 

Zirphaea dentata Gabb Cancellaria sp. 

Lucina borealis Linn. Trophon sp. 

Diplodonta harfordi n. sp. 

It is apparent that not onl}^ are the characteristic Reef Bed 
fossils absent from this list, but there are some forms intro- 
duced, as for instance the first two and nearly all of the 
gasteropod species. 

The Oyster sands, with their associated gigantic Tamiosomay 
Pecten, etc. are well developed on the N. E. Yx of Sec. 19, T. 
18 S. , R. 14 E. , and can be easily followed toward the south- 
east to the vicinity of the wells of the California Limited Oil 

Another feature of the basal portion of the Coalinga Beds 
between Salt Creek on the north and the wells of the Cali- 

NoTE. In the above and following lists important or characteristic species are marked 
with an asterisk. 


fornia Limited Oil Company is the rather local development 
of heavy beds of conglomerate. These are best seen in the 
" Rainbow beds" on Sec. 4 and 10 ; T. 19 S., R. 15 E. and 
in the conglomerates crossing Salt Creek, Sec. 10, 11, and 
14; T. 18 S., R. 13 E. 

These conglomerates vary considerably in thickness, having 
their maximum development on Salt Creek, where there are 
above the Reef Beds about twelve hundred feet of heavy 
serpentine conglomerate. The conglomerates, including the 
" Rainbow beds," lie between the Reef Bed below and the 
Tamiosoma bed above, and as far as they have been followed 
they hold this relation, but at intervals give place to sandy 
beds, as in the case south and west of the California Limited 
Oil Company's wells. 

West of Coalinga the Reef Bed is not a prominent topo- 
graphic feature, but it can be recognized by its faunal con- 
tents, which contains the following species: 

*Dosinia ponderosa Gabb Pecten estrellanus Conrad 

"^Cyrefta calif ornica Gabb Zirphaea dentata Gabb 

Crepidiila excavata (?) *Mactra {Spisula) catilliformis 

*Cytherea {CalHsta) sp. (rel. C. Dall 

callosa) *Mactra {Spisula) falcata Gould 

Mytilus californianiis Conrad *Neverita recluziana Desh. 

Lucina borealis Linn. *Chrysodomus recunia Gabb 

*Metis {Lutricola) alia Conrad Purpura sp. 

Maconia nasuta Cpr. Galerus sp. 

Cytherea ( CalHsta) diabloensis Cancellaria vesper Una n. sp. 

n. sp. Nassa sp. 

* Tapes tenerriina Cpr. *Trophott sp. 
Diplodonta harfordi n. sp. *Astrodapsis sp. 

* Pecten discus Conrad 

i Oxyrhina tumula Agz. 

Vertebrates ^ Lantna clavata Agz. 
r Zyg abates sp. Agz. 

It is not unlikely, and is perhaps even probable, that the 
Coalinga Beds as here described will be found to be the 
equivalent of the Contra Costa Beds described by Merriam^ 
as belonging to the uppermost Miocene. Their noncon- 
formity' with both the Monterey Shales below and the char- 
acteristic Etchegoin Beds above is clearly shown, as pointed 

Bull. Dept. Geol. Univ. Calif, v. 3, no. 16. 


out by Mr. Owen, in the foothills directly north of Coalinga. 
It is also a significant fact that for more than sixty miles 
along the eastern side of the range, between Coalinga and 
McKittrick, they do not appear, though the Monterey Shales 
and the Etchegoin Beds are continually in evidence. 
Throughout the Salinas and other intermontane valleys to 
the west, the Coalinga Beds appear to be present in con- 
siderable thickness. 

Etchegoin Beds. 

No other formation in the Mount Diablo Rangfe has so 
great an areal extent and so great a thickness and continuity 
as the Etchegoin Beds, which overlie in turn all of the 
older formations of the region, resting upon each respec- 
tively with a distinct nonconformity. The relations of this 
formation to the others in the Coalinga field are shown in 
the accompanying map (PI. xxxv) and sections (PL xxiv). 

The maximum stratigraphic thickness of the Etchegoin 
Beds in their greatest development is certainly not less than 
seventy-five hundred feet, while at other points they do not 
exceed five thousand feet. In some sections they have the 
appearance of aggregating the incredible thickness of nine 
thousand feet, but such a development is probably local. 

Sands, usually but little consolidated, form the predomin- 
ating element and make up locally three-fourths of the 
entire series, occurring chiefly at the bottom or in the lower 

The name of this formation has been derived from its 
characteristic development in the vicinity of the Etchegoin 
ranch, some twenty miles northeast of Coalinga. 

A detailed description of the divisions of the Etchegoin 
Beds is hardly possible from our present knowledge of them, 
but a general statement will perhaps be useful in identifying 
them in the field and in correlating them with similar forma- 
tions elsewhere. 

Etchegoin Sands. — Occupying a stratigraphic position 
at the base of the Etchegoin and forming almost two- 
thirds of its mass, are unconsolidated sands or gravels in 


which a characteristic blue or bluish gray color predomi- 
nates, at least in certain localities. In the vicinity of the 
Etchegoin ranch, some twenty miles northeast of Coalinga, 
these blue sands are distributed in three prominent horizons 
including about twelve hundred feet of strata. They can be 
traced with more or less continuity throughout the field from 
the Cantua southward to the Sunflower V'alley. 

The blue color has been generally found to be a safe 
index to the identit}^ of the beds and has been recognized in 
the vicinity of Mount Diablo and on San Pablo Bay. It is 
not claimed, however, that it is constant or characterizes any 
particular strata within this division. In thickness the 
Etchegoin Sands vary considerably. Near the Cantua 
the thickness appears to be less than on the Etchegoin 
ranch, while south of Alcalde the thickness is considerably 

In the vicinity of Kreyenhagen's where the Etchegoin has 
its greatest development, the strata included within the limits 
of the blue sands are twenty-five hundred feet, of which 
ordinary gray sand and gravels form the larger portion. Many 
of the pebbles are jet black in color. 

The Etchegoin Sands are commonly coarse in texture and 
often pebbly, forming beds of conglomerate. There is an 
appearance of volcanic ash or Kaolin-like matter throughout 
the colored zones, and their characteristic color may be 
partly due to this material, but the exact nature of the color- 
ing matter has not been determined. 

One or two fossil horizons are to be recognized in the 
Etchegoin Sands, one near their bottom and another some 
distance above, but whether persistent or not cannot be 
stated. The more characteristic horizon is that near the 
bottom of this division and includes the following species: 

Pseudocardiurn gabbi Remond Scute lla sp. 

Area trilitieata Conrad Mytilus (large sp. ) 

My a arenaria Linn. Ostrea attwoodi Gabb 

Pectunculus sepientrionalis Midd. Cardium meekiatimn Gabb 

The second fossil horizon occurs higher up in the beds, 
nearer their top, and contains the following: 



Area trilineata Conrad 
Saxidomus aratus Gould 
Pecten coalinga'ensis Arnold 
Pecten wattsi Arnold 
Pecten etchegoini n. sp. 
Chania sp. 
Ostrea sp. 
Tellina sp. 
Ballanus sp. 

Neverita recluziana Desh. 
Nassa californica Conrad 
Terebratella sp. 
Clype aster {Scut ell a) brcweriana 

Scutella gibbsi Remond 
Astrodapsis tumidus Remond 
Sharks' teeth, etc. 

Southward on the Jacalitos Creek similar beds near the 
base of the Etchegoin series contains the following species : 

*Mactra {Mulinia) densata Conrad Pecten crassicardo Conrad 

*Mactra {Spisuta) falcata Gould 
* Metis {Lutricola) alia Conrad 

Macoma nasuta Cpr. 

Pectunculus septenti-ionalis Midd. 

Saxidomus aratus Gould 

*Hinnites sp. 

* Trophon ponder o sum Gabb 

* Chrysodomis sp. 
Nassa sp. 
Natica sp. 

West of Coalinga where the Etchegoin Beds are well 
exposed and fossiliferous, they contain: 

Mactra {Spisuta) falcata Gould 
Metis {Lutricola) alta Conrad 
Saxidomus aratus Gould 
Tapes staleyi Gabb 
Pecten oweni Arnold 
Area trilineata Conrad 
Pectunculus septentrionalis Midd. 
Cardimn meekianunt Gabb 

Diplodonta harfordi n. sp. 
Macoma secta Conrad 
Pseudocardium sp. 
Nassa californica Conrad 
Neverita recluziana Desh. 
Pleurotoma {Surcula) sp. 
Scutella gibbsi Remond, etc. 

A comparison of these lists with the lists published by 
Whitney^ and others for the Pliocene occurring at Kirker's 
Pass, Contra Costa County, makes it evident that faunally 
they are of the same group of strata. Furthermore a few 
days spent by the writer in studying and collecting from the 
beds occurring on the east shore of San Pablo Bay, Contra 
Costa County, led to the conclusion that the two thousand or 
more feet of Pliocene strata occurring there on the southern 
side of the syncline is the equivalent of the Etchegoin Sands 
and represents only the basal portion of the Etchegoin Beds 
in their full development. The same fauna can be recog- 
nized also a little to the north of Walnut Creek Station on 
the railroad running to San Ramon. The lowest faunal 

Geol. Surv. Calif. Geol. v. i, p. 32. 


horizon on San Pablo Bay is equivalent to that of the lowest 
horizon described in the Etchegoin Sands. Among the more 
characteristic species are the following, from the bay-shore 
north of Pinole : 

Astrodopsis turnidus Remond Mactra falcata Gould 

Pecten pablo'cnsis Conrad Pectunculiis seplentrionalis Midd. 

Pecten crassicardo Conrad Saxidomus aratiis Gould 

San Joaquin Clays. — The clays at the upper part of the 
Etchegoin, from Coalinga northward, occupy at least a third 
of the entire series, or about fifteen hundred feet in strati- 
graphic thickness. At a distance these clays present a 
banded appearance from the zones of color seen in the dif- 
ferent strata, some of which have a width of two hundred or 
three hundred feet. These clays are overlain by fresh water 
deposits in the vicinity of Tulare Lake and the Kettleman 
Hills to the depth of one thousand feet or more. 

No fossils have been found in them north of Coalinga, 
but north of Tar Springs, Kings County, specimens of Scu~ 
tella o-ibbsi and teeth of sharks have been found. 


Tulare Formation. 

Overlying the San Joaquin Clays of the Etchegoin series 
there are thick strata of gypsiferous sands and clays exposed 
at intervals along the western border of the Great Valley. 
In the Kettleman Hills, ten to fifteen miles southeast of Coa- 
linga and near the western shore of Tulare Lake, these beds 
aggregate fully one thousand feet in thickness, though no 
attempt was made to measure them accurately. They lie 
conformably upon the San Joaquin Clays and in some 
respects resemble them, so that it is not always possible to 
discriminate accurately betw^een them. Where the Tulare 
beds are exposed in the Kettleman Hills they have been 
noted by W. L. Watts S who gives a sectional view of the 
Pliocene beds with which he classes these. Some of the 
beds contain an abundance of fresh -water mollusks, and 

1 Bull. no. 3, Calif. State Min. Bur. 1894, p. 55. 


among those collected by Watts the following species were 
identified by Dr. J. G. Cooper: 

Anodonta decurtata Conrad Margaritana subangulata Cooper 

Anodonta nuttaliana Lea Physa costata Newcomb 

Amnicola turbiniformis Tryon Planorbis tutnens Carpenter 

Carmifex newberryi Lea Sphaeriuni dentaiutn Hold. 
Goniobasis occata Hinds 

Their classification as Pliocene is perhaps supported only 
by their conformable position on the Etchegoin claj'S, but in 
view of the fact of their fresh-water origin, the determination 
is not conclusive. 

Similar beds are also described by Watts ^ from the vicinity 
of McKittrick (Sec. 34, T. 30 S., R. 22 E.) where the 
following species were obtained : 

Anodonta nuttaliana Lea 
Carinifex newberryi Lea 
Poinatiopsis intei'media Tryon 

It has been suggested that these beds might be correlated 
in part or whole with the Orindan beds described by Dr. 
Lawson^ from the Berkeley Hills and other points in Contra 
Costa County. If such be the case their occurrence is prob- 
ably continuous along the whole western border of the 
Great Valley, and probably also to the north of the Straits 
of Carquinez. 

Stratigraphic Relations. 

With few exceptions, notably that of the later sedimentary 
beds desiffnated as the Tulare Formation, the entire collec- 
tion of stratified rocks described in the foregoing pages is 
essentially marine. While the coal beds of the Eocene may 
represent a condition somewhat different, it is evident that 
these beds are local and have not a great stratigraphic range. 

In the case of all the later series, beginning with the Creta- 
ceous, there is a considerable uniformity of strike and dip in 
many parts of the range. From stratigraphic evidence alone 

1 Bull. no. 3, Calif. State Min. Bur. 1894, p. 49. 

2 Bull. Dept. Geol. Univ. Calif, v. 2, pp. 371 et seq. 


it is often impossible to discriminate between the rocks of the 
several periods. In most places there is an apparent strati- 
graphic conformity between Cretaceous and Eocene, and 
between the latter and Miocene strata. And in most sec- 
tions, likewise, the Pliocene (Etchegoin) rocks rest conform- 
ably upon the older series. Dr. Becker and C. A. White ^ 
believed that the entire collection of Cretaceous, Eocene, 
and Miocene strata formed a continuous and conformable 
series, and this opinion was held after observations had 
extended over a considerable portion of the Mount Diablo 
Range. • 

The lithological variation of the rocks is considerably 
greater, and characteristic types are the rule in all of the 
principal epochs. It is often possible to recognize without 
the aid of fossils many of the typical members of the strati- 
graphic groups. Probably the most trustworthy guide for 
the identification of strata in all cases is that afforded by 
paleontology, but in the later formations the persistence of 
some of the fossil forms from the earliest Miocene to the 
Present makes it necessary to use them with caution. With- 
out the aid of other stratigraphic data and the recognition of 
lithologic peculiarities it would often be difficult to distin- 
guish between the Lower Miocene and the Coalinga Beds, 
while both of these series contain forms that are still living 
alonjj the west coast. However, there are a few forms that 
have been found to be sufficiently trustworthy within provin- 
cial limits, but it is doubtful if many of them would support 
extensive generalizations. 

Dr. Merriam has pointed out" that Agasoma gravidum, 
Tjirritella ocoyana, and T. hoffjnanni are characteristic of the 
lower Miocene, and all of these have been found in the Tem- 
blor Beds of the Mount Diablo Range, along with man\- other 
forms occurring in the typical Lower Miocene beds of Kern 

Similarly certain forms of Pecteii, Mactra, Scutella, and 
Astrodopsis are believed to belong only to the Etchegoin 
Beds, but it will require at least a reasonable degree of 

1 Bull. no. 15, U. S. Geol. Surv. pp. 14, 15 et seq. 

2 Bull. Dept. Geol. Univ. Calif, v. 3, pp. 377-38i- 


specific discrimination to maintain this generally, as several 
forms of each occur at intervals from the early Miocene to 
the Present. Pseudocardimn gabbi of the Pliocene resembles 
Midiiiia densata, occurring in both the Upper and Lower 
Miocene, and in like manner closely allied species of Saitella 
and Astrodopsis occur in both the earl}- Miocene and the 
San Pablo. 

There is evidence of nonconformity between the rocks of 
all of the successive periodic series, and in some cases 
between the different members of the same series. The 
nonconformity between the Chico and Eocene is well shown 
by a detailed study of the field north of Alcalde Creek. 
The nonconformity is both stratigraphic and faunal, but the 
evidence of either class becomes more convincing only as it 
becomes better known. In the case of the Eocene and Mio- 
cene nonconformity the evidence is also both faunal and 
stratigraphic, the latter appearing more satisfactory from the 
fact that the Lower Miocene rests in turn upon the Eocene, 
the Cretaceous, and the Franciscan rocks. 

The relations of the Pliocene (Etchegoin) formation to 
the earlier ones has been shown in the preceding pages and 
on the map of the Coalinga district (PI. xxxv), but the evi- 
dence shown there is only partial. 

What evidence the field might afford as to the relation of 
the Etchegoin to later rocks has not been ascertained, beyond 
the fact of a transition from marine to fresh-water conditions. 
It is conceivable that such a transition might be effected so 
gradually by normal causes that no stratigraphic noncon- 
formity would exist, but such a transition in this case requires 
to be shown. In the Berkeley Hills the Orindan Formation 
rests unconformably upon the Monterey Shales, and their 
basal portion is pebbly conglomerate. If the Tulare Beds 
are to be correlated with the Orindan, the individuality in 
each case would be the same. 

There is, however, a stratigraphic member still to be con- 
sidered, whose exact relationship is less evident, though 
probably not so difficult as it might appear. This remark 
concerns the Coalinga Beds. They have been followed 


throughout a distance of twenty miles along their outcrop, 
where they are almost entirely uncovered, regularly stratified, 
and quite fossiliferous. Where they rest upon the Monterey 
Shales, which for the greater part of the distance they do, 
there is but little appearance of stratigraphic divergence, 
except an abrupt transition from fine to coarse sediment. In 
their dip and strike there is considerable uniformity, at most 
points at least, though there is at some points a sudden 
change from the hard shales of the Monterey to the soft 
coarse sands and conglomerates of the Coalinga Beds. As 
they are followed along their contact, however, as they can 
be easily for many miles, the Coalinga Beds are not only 
found resting upon different portions of the Monterey at dif- 
ferent points, but toward the south they rest in turn upon 
Monterey Shales, the Eocene, and the Chico. 

The nonconformity therefore of the CoaHnga Beds with 
all of these older series may be considered equally clear. 

The stratigraphic nonconformity of the Coalinga Beds, 
on the other hand, with the Etchegoin Beds is also equally 

This is best shown near the northeast corner of the map of 
the Coalinga field, or about seven miles north of Coalinga. 
As the basal beds of the Etchegoin are followed westward 
through the field, they rest upon, and then close out succes- 
sively lower and lower strata of the CoaHnga Beds until 
finally the latter disappear from the stratigraphic section 
entirely, and the Etchegoin Beds are found resting upon the 
Monterey Shales. A similar occurrence may perhaps also 
be seen west of CoaHnga, where the Etchegoin Beds are 
found passing from the CoaHnga Beds to the underlying 

A faunal study of the CoaHnga Beds shows them more 
closely related to the Temblor than to any later or living 
faunas. Notice for example in the basal CoaHnga — that is 
in the Reef Beds — the occurrence of Agasoma kernianum. 
Area montereyana, and Pecten discus, besides many other 
forms closely alHed to those of the Temblor Beds. 


Other Occurrences of Lower Miocene within the 

Interior Basin. 

For purposes of comparison and for a more complete 
understanding of the Lower Miocene fauna within the inte- 
rior basin of California, brief descriptions of other occurrences 
are here given. In a short paper recently published by Dr. 
Merriam^ the Lower Miocene beds of Contra Costa County 
are described, including a partial list of fossils. The beds are 
said to rest directly upon the Tejon, and to be overlain by 
beds of Monterey Shale. The most characteristic species 
are : 

Aj^asoma gravidum Gabb Chione mathewsoni Gabb 

Dosinia matheivsoni Gabb Mytilus mathewsoni Gabb 


The stratigraphic thickness of these beds was not given, 
but it is probably commensurate with that of the Temblor 

San Emidio Sf.ction. 

An instructive section of the rocks of the San Emidio 
Canyon is to be found in Whitney's^ description. In refer- 
ring to this illustration, however, it is necessary to remember 
that Eocene rocks were classed by him as Cretaceous. 

Overlying the Eocene beds are beds of Lower Miocene 
age with a fauna similar to that already described for the 
Temblor Beds. 

The dip is toward the north at a high angle, and the strike 
is conformable to that of the Eocene and later rocks. The 
Monterey Shales are missing from this section, or if present 
were not recognized. The beds may be traced westerly and 
northwesterly toward the Carisa, toward McKittrick and 
Temblor, and perhaps easterly toward the Tejon ranch. 

Beds of the Carisa Ranch. 

Near the Carisa ranch house, along the San Juan River, 
San Luis Obispo County, an enormous thickness of Miocene 

1 Bull. Dept. Geol. Univ. Calif, v. 3, pp. 377-381. 

2 Geol. Surv. Calif. Geol. v. i, p. 189. 


rocks is exposed with a dip of 40° to 60*^ to the northeast. 
The series consists of alternatincr horizons of sandstone and 
siliceous shales, the former of which greatly preponderate. 

The lowest fossil horizon near the base of the series, and 
the second one some thirteen hundred feet above the base 
contained ver}' nearly the same fauna, from the latter of 
which the following species were collected : 

Turritella ocoyaiia Conrad Cytherea {Callisia) mathewsoni 

Trochita filosa Gabb Gabb 

Agasoma gravidiim Gabb Dositiia mathewsoni Gabb 

Crcpidula grandis Conrad Mytilns mathewsoni Gabb 

Crepidida p7-aert(pta Conrad Lucina richthofeni Gabb 

Neverita callosa Gabb Pec ten estrellatms Conrad 

Fusus {Hemifusus) icilkesana n. sp. Pecten sp. 

Scaphander jugulai-is Conrad Glycimeris estrettanus Conrad 

A third fossiliferous horizon within twenty-five hundred 
feet of the top of the Miocene series yielded essentiall}' the 
same fauna with one or two additional forms, as Pecten 
nevadensis, Oliva calif ornica n. sp., and an undescribed 
species of Dosinia, etc. This horizon is well exposed about 
four miles southeast of La Panza Springs on the east side of 
the San Juan River. It is overlain by shaly beds with a 
fauna resembling that of the Monterey Shales. 

Kern River Beds. 

Although this locality' was not specially studied, and lies 
without the Mount Diablo Range, still it has long been 
known, and lies within the interior basin of California. 
The locality is on Kern River, two to six miles east of Oil 
City, Kern County. The strata are mainly sands and sand}' 
clan's, dipping gently toward the west. The entire thickness 
of the strata exposed along the river aggregates about three 
thousand feet, of which the lower two-thirds belongs to the 
Miocene. Toward the base they become very fossiliferous, 
containing numerous species of invertebrates, teeth of sharks, 
and bones of fishes and other marine vertebrates. 

The following species were collected in the vicinity of 
Barber's ranch, chiefly north of the river: 

[3] October 25, 1905 



Agasoma gravidtini Gabb 
Agasoma kernianum Cooper 
Agasoma sinuahmi (?) Gabb 
Conus otveniana n. sp. 
Neverila callosa Gabb 
Turritella ocoyana Conrad 
Ctinia biplicosta Gabb 
Oliva californicus n. sp. 
Scaphander jugularis Conrad 
Trophon kernensis n. sp. 
Dentalium subsiriafiwi Conrad 
Dentaliiiin sp. 
Pleurotoma ( ClathureUa) dumbleana 

n. sp. 
Nassa arnoldi n. sp. 
Trochita filosa Gabb 
Crcpidula pracrupta Conrad 
Purpura lima Martyn 
Sigarctus scopulostis Conrad 
Terebra cooperi n. sp. 
Bullia {Molopophorus) anglona^ia 

n. sp. 
Cancellaria pacificus n. sp. 
Cancellaria joaquinensis n. sp. 
Cancellaria condoni n. sp. 

Cancellaria simplex n. sp. 
Cancellaria dalliana n. sp. 
Cy there a ( Callista) niathezvsoni 

Vemis {JMercenaria) pertemiis 

Venus ( Chione) teniblorensis n. sp. 
Dosinia ^nalhewsoyii Gabb 
Dosinia sp. 

Mactra {Spisula) /alcata Gould 
Mactra sp. 

Pachydesma inezana Conrad 
Pecten discus Conrad 
Solen sicarius Gould 
Solen sp. 

Tcl/ina ocoyana Conrad 
Tellina sp. 

Yoldia impressa Gabb 
Lucina richthofeni Gabb 
Area montcreyana Osinont 
Corbicula dumbleana n. sp. 
Leda oregona Shumard 
Cytherea sp. 
Hotnomya sp. 
Pectunculus sp. 

Many yet undescribed species occur in this collection, and 
the locality is well worth a more exhaustive stud3\ On the 
whole it probably better represents the Lower Miocene 
fauna of the California interior than an}^ other locality 
that has been described. 


It is not at present possible to correlate with much accuracy 
the Tertiary beds of the Mount Diablo Range with others 
occurring in distant parts of the Coast or of the State. 
For the Pliocene, and perhaps also the Miocene periods, a 
number of minor provinces must be recognized along the 
Pacific border, corresponding to the physical geography of 
the time. North of the Klamath Mountains the Miocene 
and Pliocene faunas are in a measure specifically different 
from those of Central California, while these are in turn 
somewhat unlike those of the southern coast of California. 


The exact line of separation between the Cahfornian prov- 
inces of the later Neocene appears to follow very nearly the 
line of the outer Coast Ranges as far south as the head 
waters of the Salinas Valley drainage, and follows in turn 
the axis of the Santa Cruz and the Santa Lucia ranges, 
turning eastward to Pine Mountain and the Tehachapi 
Range at the latitude of Moro Bay. The Pliocene beds of 
the coastal valleys south of the Santa Lucia Range are 
faunally more closely related than any of them are with the 
Pliocene of the interior valleys. The interior basin of the 
Pliocene includes not only the Great Valley, but the Salinas 
and Carisa valleys and other small valle3's of the Coast 
Ranges, probably extending as far north as Lake and 
Tehama counties. 

Within these provincial limits a faunal and stratigraphic 
correlation of Pliocene deposits, at least, is likely to be more 
successful than are present attempts at a detailed correlation 
of deposits within two or more provincial basins. 

In the Salinas Valley occur late Tertiary beds that can be 
satisfactorily compared and correlated with those of the 
Mount Diablo Range. At Santa Margarita and on the 
Nacimiento River, at La Panza Springs, and on the Estrella 
and San Lorenzo rivers, are beds that are entirelv similar. 
At Santa Margarita these beds have been mapped and 
described by H. W. Fairbanks' as the Santa Margarita For- 

It is quite likely that a correlation of the INIiocene beds, 
or at least of some of them, will have to be restricted within 
the same territorial limits. The Vaquero sandstones described 
by Dr. H. W. Fairbanks as occurring within the drainage of 
the Salinas River lack thus far any faunal description, and 
his correlation of these with beds occurring south of the 
Santa Lucia Range is not supported by any faunal evidence. 
On the other hand the fauna occurring at the base of the 
Miocene near San Luis Obispo is characteristic over the 
whole extent of the coast border, especially south of that 

1 San Luis Folio, U. S. Geol. Surv. no. 101. 



The conclusions to be arrived at from the stratigraphic 
study of this field are not at variance with, but are mainly 
confirmatory of much that has been written during the last 
decade. The Tertiary^ formations of California have thus far 
been too little studied and analyzed, though for general scien- 
tific as well as for economic reasons they richly deserve 
attention. In the present contribution to the literature it is 
believed that the following points are either made clear or are 
at least clearly indicated : 

1. Stratigraphic nonconformities exist in the Mount Dia- 
blo Range between all of the chief periodic series, and in 
some instances between different members of the same 

2. The Eocene strata are capable of being divided into 
several distinct members, of which the Tejon portion contains, 
at least locally, two sandy members separated by one of 

3. The Neocene deposits of California can be separated 
into two or more basins or minor provinces, those of the 
Mount Diablo Range belonging to the California interior 
basin and being characteristic of the same. 

4. In the Mount Diablo Range two clear stratigraphic 
nonconformities exist within the Neocene, dividing these 
deposits into three groups, lower, middle, and upper. The 
lower and older of these groups contains the well recognized 
Miocene strata of Central California ; the later and younger 
group, the strata which have been described as Etchegoin or 
San Pablo, and which are believed to be of Pliocene age: 
while the interv^ening or middle group, on account of its 
faunal resemblance to the older Miocene, is more logically 
classed in this period than in the period following. 

5. In the older Miocene two distinct members are to be 
recognized; viz., the Monterey Shale and the Temblor 

6. The most complete and therefore the most typical 
fauna of the Lower Miocene of the California interior is that 


of the Kern River Beds on the southeastern border of the 
San Joaquin Valley. 

7. The most complete and typical development of the 
San Pablo strata is not found in the locality from which it 
takes its name, but along the northeastern flanks of the Mount 
Diablo Range, as in western Fresno County, where the series 
attains more than four times the thickness stated in its original 

8. The Etchegoin series is capable of being subdivided, 
at least locally, into two or more separate members, each of 
which has a greater stratigraphic thickness than was origin- 
ally given for the entire body of similar beds occurring on 
San Pablo Bay, which are altogether embraced in the lower 
division, the Etchegoin Sands. 

9. The uppermost stratigraphic unit of the Mount Diablo 
Range is one of fresh-water origin, and is perhaps equivalent 
to the Orindan Formation of the Berkeley Hills, as described 
bv Dr. Lawson. 

10. The Neocene faunas of California are far from being 
completely known ; thev offer a rich field for study, and it is 
believed that such study would yield results of great value to 
students of stratigraphic geology. 

Descriptions of Species. 

Amons: the manv fossils collected in the Mount Diablo 
Range and the California interior during the field-study 
represented in the foregoing paper, many new species have 
been discovered, some of which are here described. 

While undescribed forms have been obtained from both 
Cretaceous and Tertiary strata, the latter only are illustrated 
in the following pages. The list of new forms from each of 
the Tertiarv horizons might be considerably extended b}^ the 
use of fragmentary and imperfect materials, but the descrip- 
tion of such material is not only unsatisfactory but results in 
much harm to paleontologic science. 

]Many of the California Tertiary invertebrates were origin- 
ally described in literature that has become inaccessible, and 


some of the accessible literature contains only unsatisfactory 
figures and descriptions; therefore it is highly desirable to 
have re-descriptions and better drawings made when authen- 
tic material can be obtained and properly identified. The 
species figured and described by Conrad in the Pacific Rail- 
road Reports can rarely be identified except from the type 
localities, and then only by the utmost care and reservation ; 
the same is often true of the species described by Gabb in 
the Paleontology of California. Much of the confusion and 
uncertainty in stratigraphic determination in the Pacific Coast 
Tertiary originates in such faulty descriptions. Correct 
specific determinations cannot be made from much of the 
literature upon California paleontology that is accessible to 
students of the subject, and until these can be made, trust- 
worthy determinations of faunal horizons are likewise impos- 

Where any departure has been made from the current 
paleontological nomenclature it has been with deference to 
the classification proposed by Zittel in his Handbuch der 
Palceontologie, and it must be confessed that such a standard 
should have been adopted throughout. An attempt to do 
this would, however, involve a considerable amount of work 
in revising the Pacific Coast nomenclature, and that is beyond 
the purpose of this paper. 

The paleontological materials that form the basis of this 
study have been largely collected by the writer ; they have 
become the property of the California Academy of Sciences, 
and are a part of its permanent collections. 



Plate XIII, Figs. 9-29. 

For the purpose of calling attention to the many well pre- 
served forms of Foraminifera in the Eocene rocks of the 
Mount Diablo Range, and to illustrate some of the more 
common genera, a few have been figured without any attempt 


at specific identification, along with other Eocene species 
occurring in very nearly the same horizon. These Foramin- 
ifera are as follows: 

Nodosaria Cyclammina 

Lagena (?) Pulvulina 

Sagrina Polymorphina (?) 

Some of the species of Foraminifera are very large, and 
can be easily seen with the unaided eye. Some species of 
Nodosaria attain a length of three-fourths of an inch, and all 
of them are easily distinguished with a good lens. Most of 
the forms are found in calcareous concretionary masses, 
occurring as lenses in the argillaceous beds described in 
this paper as the Kreyenhagen Shales. 


Eocene and Miocene. 
Scutella sp. A. n. sp. 

Plate XIII, Fig. 8. 

Test small, thin, disk-like, oval or sub-pentagonal; anal pore supermar- 
ginal; apical star symmetrical, but not central; calyx open. 

The numerous specimens of this species which were found, 
are immature and cannot yet be satisfactorily described. 
Most of them are laterally convex and small. 

Occurrence. — The species is not rare in the Avenal Sands 
west of Coalmga. 

Astrodapsis merriami n. sp. 

Plate XIV, Figs. 33 and 34. 

Disk small, circular, depressed; margin only slightly notched at the 
ambulacral extremities; apex central, only slightly elevated, star symmet- 
rical, petals equal but not reaching the margin of the disk, and slightly 
elevated; anal pore marginal; ambulacral furrows of inferior surface straigiit 
and simple. The largest specimens have a diameter of i)^ inches, though 


the usual size is }^ of an incli. The disk is thin and flattened but shows a 
decided tendency to form elevated stars on the upper surface. 

Occurrence. — This form is extremely abundant locally in 
the Temblor Beds of the Mount Diablo Range, at Tar 
Springs, Kreyenhagen's, and Temblor. 

Cassidulus californicus n. sp. 
Plate XIII, Figs. 6 and 7. 

Test small, elliptical, robust and often somewhat globular; lower surface 
flattened, or concave, upper surface convex; mouth not central, round, and 
occupying a position ^-^ of the distance from the anal margin; anal pore ter- 
minal; apical star nearly symmetrical, central on dorsal surface; tubercula- 
tion distinct, the tubercules lying within rounded pits. There is a tendency 
to form shoulder-like expansions on the periphery behind the position of the 

Ocairrence. — This species is not rare in the Avenal Sands 
west of Coalinga. 



Spondylus carlosensis n. sp. 

Plate XIII, Fig. i. 

Shell of medium size, sub-circular or obliquely ovate, radially ribbed, 
convex; costae granulated or obscurely spinose; ears and hinge rather 
broad. The costae radiate in graceful, sinuous lines from the beak to the 
margins, and occur in pairs or triplets, every second or third rib being inore 
elevated than the others. 

Occurrence. — This species occurs only rarely in the Avenal 
Sands west and north of Coalintja. 


Ostrea aviculiformis n. sp. 

Plate XIII, Figs. 3-5. 

Shell small, very inequivalve, quadrate, oblique, laminated; inferior 
valve convex and strongly arched; superior valve thin, often concave, and 
sharply laminated in thin concentric folds; hinge broad and somewhat 


straight. The surface of the convex valve is marked only by concentric 
lines of growth. The margin is more or less ragged or irregular. 

This species bears some resemblance to Ostrea sellaeforniis 
Conrad, from the Eocene of Alabama. 

Occurrence. — This species is found only occasionally in the 
Avenal Sands west and north of Coalinga. 

Cyrena (Corbicula) dumblei n. sp. 

Plate XIV, Figs. 30-32. 

Shell moderate in size, or large, 3 inches in greater diameter; sub-circular 
in outline; beaks central, not greatly elevated, incurved; surface marked by 
heavy and irregular concentric ridges, or smooth in young shells; teeth sharp 
and prominent; lateral tooth long and slightly curved and finely crenulated. 

This species differs from C. californica Gabb in being 
larger and more circular in outline and in having generally a 
more robust form. 

Ocairrence. — This species is not rare in the lower Miocene 
beds of Kern River. 

Venus (Chione) pertenuis Gabb. 

Venus pertenuis Gabb, Pal. Calif, v. 2, pp. 22 and 55, pi. v, fig. 37. 

In Gabb's description of this species there is some doubt 
expressed as to its proper sub-generic determination, though 
he says it very probably may prove to be a Chione. Several 
specimens have been obtained from the Lower Miocene beds 
of Kern River, some of them showing the hinge from which 
Gabb's judgment is readily confirmed. 

Venus (Chione) conradiana n. sp. 

Plate XIV, Fig. 35. 

Shell large, rather thick, cordate, broadly rounded below, and much 
produced behind; beak prominent, anterior, incurved; lunule large; surface 
marked by concentric ridges, strongest in the umbonal region; margin thin 
and not crenulated. 


This shell is related to Chiofie pertemtis Gabb, but has not 
the triangular outline of that species, is more produced pos- 
teriorily, and less produced before. The hinge is fairly well 
exposed showing its generic features unmistakably. 

Occurrence. — This species occurs with C. per tennis in the 
Lower Miocene beds three miles east of La Panza Springs, 
San Luis Obispo County. 

Venus (Chione) temblorensis n. sp. 

Plate XIV, Figs. 36-38. 

Shell moderate in size, 2% inches in larger diameter, i>^ inches thick; 
sub-triangular in outline; beaks slightly anterior; incurved; lower margin 
rounded, crenulated within, produced to an angle posteriorly; hinge margin 
straight; surface ornamented with concentric ridges and radiating ribs. The 
concentric ridges rise in gently fluted and ruffled folds. The radiating ribs 
occur singly from beak to margin. 

This species is undoubtedly related to C. guidia Brod. & 
Sow. but is ornamented with single instead of double ribs or 
riblets, less prominent concentric folds, and generally differ- 
ent outline. It is perhaps ancestral to the latter species. 

Occurrence. — Lower Miocene beds of Kern River and 

Cylherea (Callista) diabloensis n. sp. 
Plate XVII, Figs. 83-85. 

Shell large, thick, obliquely cordate in outline; beaks prominent, anterior, 
incurved; margin broadly rounded below, produced in front; cardinal 
region widely excavated; lunule large, impressed; surface ornamented by 
smooth concentric ridges, more or less interrupted as in C. callosa Conrad; 
inner margins not crenulated. 

This species resembles specimens of C. callosa from the 
California coast, but is shorter and has a greater lateral 
thickness. Moreover it does not show the internal thicken- 
ing of the valves as in C. callosa. 

Occurrence. — This species is not uncommon in the Coalinga 
Beds west of Coalinga, Fresno County. 


Pectunculus septentrionalis Middendorf. 

Plate XVII, Figs. S6 and 87. 

Pcciunculus septentrionalis (Midd.) Carpenter, Brit. Assn. Rept. 1856, 

p. 219. 
Glycymeris septentrionalis (Midd.) Arnold, Mem. Calif. Acad. Sci. v. 3, 

p. loi, pi. XVIII, fig. 10. 

This species is well described by Arnold, though the 
sculpture of the shell is not shown in his figure. It will be 
noticed upon a comparison of the figures that the form from 
San Pedro has a smaller ligamental area and a somewhat 
higher beak than the form here represented. 

Occurrence. — This species is abundant in the Etchegoin 
Beds both north and south of Coalinga, and is identical with 
or closely related to a similar species occurring in the San 
Pablo Beds on San Pablo Bay, Contra Costa County. 

Diplodonta harfordi n. sp. 

Plate XVII, Figs. 88 and 89. 

Shell not large, rotund, sub-quadrate in outline; beaks nearly central, low, 
closely approaching each other; cardinal margin straight, excavated; anterior 
margin sometimes a little produced, but generally rounded; surface marked 
only by concentric lines. 

This shell is allied to D. orbella Gould, but has a less 
prominent beak and a straight hinge margin. 

Occurrence. — This shell occurs abundantly in the Coalinga 
Beds west of Coalinjra. 

Pecten coalingaensis Arnold. 

Plate XVIII, Figs. 94-98. 

Pecten {Pecten) coalingaensis Arnold. 

Shell moderate in size, the largest having a diameter of ^}i inches; 
inequivalve, radially ribbed; lower valve convex, upper concave. 

Arnold's description of this species is not yet published, 
but as the specimens here figured are from his type locality 
and have been identified by Dr. Arnold, there is no doubt 


about the correctness of the determination. They have 
been referred by Arnold to the Miocene of the Kreyenhagen 
ranch, but the true horizon is that of the Etchegoin Beds, 
which are probabh' Pliocene. 

Ocairreuce. — This species is common in the Etchegoin 
Beds of the Mount Diablo Range, at the Kreyenhagen 
ranch on Zapata Chino Creek. 

Pecten wattsi Arnold. 

Pecten ivattsi Arnold, Tert. and Recent Pectens of Calif., Profess. Paper 
no. — , U. S. Geol. Siirv. . 

Ocairreuce, — This species occurs with the preceding. 

Pecten etchegoini n. sp. 

Plate XVIII, Figs. 92 and 93. 

.Shell rather large, thick, and ovate in outline; ears nearly equal, costate; 
ribs strong and grouj^ed in sets of 3 or 4, forming radial undulations in the 
shell, seen both within and without; margin of valve fluted within. The 
grouping of the ribs is a variable feature of the shell. In some specimens 
the depressions are wider, in others narrower than in the one figured. Con- 
centric lines are usually visible on the shell. 

Occurrence. — The species occurs with the two preceding 
in the Etchegoin Beds of the Kreyenhagen ranch on Zapata 
Chino Creek. 



Cypraea fresnoensis n. sp. 

Plate XIII, Fig. 2. 

Shell of medium size, i>^ inches long, i inch in diameter, robust or sub- 
globose; spire covered; canal produced a little in front. The epidermis 
covers the spire in adult age, though in the figured specimen it has been 
removed. The aperture is narrow and curved. The dentition is not shown. 

Occurrence. — This species is rare in the Avenal Sands 
northwest of Coalinga, western Fresno County. 


Cancellaria dalliana n. sp. 

Pl.\te XV, Figs. 39-42. 

Shell of moderate size, fusiform; spire high and angular; whorls angular 
and spinose; columella thickly crusted within in old specimens; surface 
marked with strong varical ridges and lines, the ridges rising in thin edges 
on the upper surface of the body whorl. The lower part of the body 
whorl is ornamented with strong revolving lines with wide interspaces in 
which there are usually 1-3 secondary lines. The canal notch is not shown. 

Occurrence. — This species occurs with the succeeding in 
the Lower Miocene beds of Barker's ranch, on Kern River. 

Cancellaria pacifica n. sp. 

Plate XV, Figs. 43-45. 

Shell moderate in size, %-\yz inches in length, width Yz as great; spire 
moderately elevated; mouth oval in outline; whorls angulated, bearing 
small nodes on the upper angles; surface ornamented with revolving lines, 
heavier and lighter lines occurring alternately on the body whorl, crossed by 
vertical ridges. 

This shell seems to be somewhat closely related to 
C. granosa Sowerby, described from Van Dieman's Land. 

Occ2irreiice, — This shell occurs with the preceding species 
in the Lower Miocene beds of Kern River. 

Cancellaria joaquinensis n. sp. 

Plate X\^ Figs. 46-48. 

Shell of moderate size, stout, and ovate; i inch or more in length and 
nearly as broad; spire medium or low, sloping evenly without conspicuous 
angles; shell thick; inner lip crusted; surface ornamented chiefly by revolv- 
ing lines and interspaces, with finer secondary lines within; varical ridges 
weak, but forming on the upper angle of the body whorl a single circle of 

This species is related only distantly to any other described 
form occurring on the Pacitic Coast. 

Occurrence. — Lower Miocene beds of Kern River, where 
four or more well preserved specimens were obtained. 


Cancellaria condoni n. sp. 

Plate XV, Figs. 49 and 50. 

Shell of moderate size, i-i>4 inches in length, }4-}^ inch wide; spire 
high; whorls angular, slightly sloping above; surface ornamented with strong 
revolving lines, with wide interspaces, crossed by strong varical ridges form- 
ing tubercular nodes on the upper angle of the whorls; inner lip crusted, 
bearing 2 spiral folds on the columella. 

This species is apparently related to the C. oregoiie?tsis 
Conrad described from the Astoria beds of Oregon. 

Ocairrence. — This species is represented by four speci- 
mens from the Lower Miocene beds of Kern River. 

Cancellaria simplex n. sp. 

Plate XV, Figs. 51 and 52. 

Shell moderate in size, simple and inconspicuously marked, resembling 
C. pacifica, but having a less elevated spire, and generally shorter whorls. 
The spiral lines and longitudinal ridges are both more reduced and the 
width of the shell is greater. The inner lip is well crusted. The length of 
the largest shell found is nearly 2 inches. 

Ocairrence. — Lower Miocene beds of Kern River, with 

the precedin 

Cancellaria vespertina n. sp. 

Pl-^vte XVI, Figs. 77 and 78. 

Shell not large, fusiform, angulated, bearing tubercules, longitudinally 
ribbed; spire elevated, but not high; whorls slightly sloping above; aperture 
ovate, inner lip crusted; canal short; surface ornamented more conspicuously 
with vertical ridges, crossed by faint spiral lines, seen more plainly on the 
lower portion of last whorl. 

The species resembles somewhat C. iirceolata Hds. but is 
less robust, with a higher spire and less prominent spiral 
ridges on the columella, besides having strong tubercules on 
the angles of the whorls. 

Occurrence. — The species is not abundant, but occurs in the 
Coalinga Beds west of Coalinga, Mount Diablo Range. 


Scaphander jugularis Conrad, 

Pl.^te XV, Figs. 56 and 57. 

Bu/la jugularis Conrad, Pac. R. R. Rept. v. 5, p. 328, pi. vii, figs. 62 
a and b. 

Shell not large, i-i>^ inches in length, width i^ as great; contracted 
toward the posterior end; aperture wide, ovate; inner lip crusted; whorl 
loosely convolute, narrowing behind; surface ornamented by revolving lines 
crossed by oblique lines of growth. The revolving lines consist of flattened 
ridges and rounded grooves of equal width. 

Conrad's figure lacks sufficient description to make abso- 
lute identification possible, but as the localities are contiguous 
and the horizon practically the same, there can be little doubt 
as to identity. 

Occurrence. — Lower Miocene beds on Kern River, a few 
miles south of Ocoya Creek. 

Oliva calif ornica n. sp. 

Plate XV, Figs. 54 and 55. 

Shell moderate in size, i-i>^ inches long, width more than half as great, 
ovate, narrowing below; spire low and rounded; aperture narrow, inner lip 
somewhat crusted; columella bearing 2 principal spiral plications, with finer 
lines both above and below; suture impressed and sharply defined on 
adolescent and mature shells; surface marked only by lines of growth. 

Occurrence. — Lower Miocene beds of Kern River, Barker's 
ranch, etc, 

Oliva futheyana n. sp. 

Plate XV, Fig. 53. 

Shell similar in many respects to the preceding, but narrower, and having 
a more elevated spire, and more graceful outline. 

Occurrence. — This shell occurs with the preceding. 

Conus oweniana n. sp. 

Plate XV, Figs. 58 and 59. 

Shell small, conical; spire moderate, conical; whorls flattened, or concave 
above; suture impressed on young shells; aperture narrow, and straight; 
surface marked by distant, fine revolving lines. 


This species is unlike C. califoruica Gabb in having a 
lower and less rounded spire, a less ovate outline, and a 
narrow straight aperture. 

Occurrence. — This shell occurs in the Lower Miocene beds 
of Kern River. 

Purpura lima Martyn. 

Plate XV, Figs. 62 and 63. 

Purptira lima Martyn, Conch, fig. 47. 

Purpura lima (Mart.) Tryon, Man. Conch, v. 2, p. 175, pi. liii, figs. 156, 
158, 159, and 161. 

Among the many moUuscan species originally described 
in obscure or inaccessible literature is the above. Authentic 
samples of this shell are in the collections of the California 
Academy of Sciences, and the identitication of the fossil 
species is from a comparison with these. The fossil speci- 
mens are a little shorter, with a less elevated spire, but the 
difference seems to be insignificant. 

Ocairrence. — The four or five samples of this species that 
have been found fossil are from the Lower Miocene beds of 
Kern River. 

Trophon kernensis n, sp. 

Plate XVI, Figs. 64 and 65. 

Shell rather large, length from 2-3 inches, width ij4 inches; graceful in 
outline, narrowing rapidly before; spire rather short, conical, and angular, 
but sloping above, bearing tubercules, or very short spines on the angles, 
more prominent on very young shells; surface ornamented chiefly by lines 
of growth, but bearing faint spiral lines on the lower part of the whorl, 
noticeable especially in young shells; aperture pear-shaped, and narrowing 
to a long canal; inner lip crusted; canal long and narrow. 

This species is only distantly related to T. ponderosum 
Gabb, but more nearly related forms are found in the Pliocene 
of California. 

Occurrence. — This shell is from the Lower Miocene beds 
of Kern River. 


Trophon gabbiana n. sp. 

Plate XVI, Figs. 79 and So. 

Shell not large, laminate, spinose on the angles; canal short, recurved; 
spire high, sloping above; body whorl tapering below. The mouth narrows 
regularly toward the canal. The spines are often considerably suppressed 
on the angles, and on the lower part of the last whorl there are numerous 
spiral lines. 

The shell differs from T. ponderoswn Gabb in having a 
recui-\^ed columella, spiral lines below, and less prominent 

Ocaun^ence. — This shell occurs in the Coalinga Beds of the 
Mount Diablo Range, nine miles north of Coalinga. 

Terebra cooperi n. sp. 

Plate XVI, Figs. 66 and 67. 

Shell of moderate size, tapering regularly; length i>^-2 inches, width of 
body whorl >^ inch or less; aperture narrow and elongated, with simple 
outer lip; surface ornamented with slightly sinuous vertical ribs or lines 
closely set on the whorls; inner lip only slightly crusted; columella with a 
narrow oblique fold on the outer side; the upper Y^ of the whorls bearing a 
constricted band, not clearly shown in the figures. 

This species is undoubtedly related to Terebra wattsiana 
Cooper,^ but is characterized by two or more distinguishing 
marks, the depressed zone on the upper part of the whorls 
and the narrow fold on the columella. A similar species 
is found in the late Pliocene beds of San Diego, California. 

Occurrence. — This species is found in the Lower Miocene 
beds of Kern River, but it is not abundant. 

Sigaretus scopulosus Conrad. 
Plate XVI, Figs. 72 and 73. 

Sigaretus scopulosus Conrad, U. S. E.xpl. Exped. (Wilkes) pi. xix, figs. 6 

and 6a/ text p. 727. 
Sinuni scopulosuui Conrad (Gabb), Pal. Calif, v. 2, p. 114, etc. 

Shell moderate in size, obliquely oval, slightly flattened above, hollowed 
below; surface marked with revolving lines, equal in width with the inter- 

1 Bull. no. 4, Calif. State Min. Bur. 1894, p. 39. 

[4] October 25, 1905 


spaces, and flattened above; spire very small, but with distinct suture; spiral 
lines not showing within. 

Three specimens in the collections of the California Acad- 
emy of Sciences are apparently referable to this northern 
species, and this determination is supported by other evi- 
dence and faunal resemblances. 

The species has a near relative in the Pliocene of San 
Fernando as seen in 6". planicostnni Gabb, but the form of 
the shell is evidently different. 

Occurrence. — Lower Miocene beds of Kern River. 

Nassa arnoldi n. sp. 

Plate XVI, Figs. 70 and 71. 

Shell small, acutely ovate; spire moderately elevated, bearing 5 whorls; 
aperture circular, outer lip always bordered by a thickened varex; columella 
short, bearing only a slight, or no sulcus; surface ornamented by spiral and 
longitudinal ridges forming a reticulation as in the young of N. perpengtiis 

This species differs from N . perpengnis in its smaller size, 
more regular and symmetrical form, shorter columella, the 
absent, or much reduced sulcus, and the bucal border which 
appears on all of the specimens that have been found. 

Occurrence. — This species occurs with the preceding in 
the Lower Miocene beds of Kern River. 

Crepidula praerupta Conrad. 

Plate XVI, Figs. 68 and 69. 

C. praerupta Conrad, U. S. Expl. Exped. (Wilkes) pi. xix, figs. 9, 9a, loa, 
\ob; text p. 727. 

Shell of medium size, i-i>^ inches long; strongly curved; aperture 
elliptical, or ovate; surface marked by irregular lines of growth. 

Occurrence. — The species is found abundantly in the Lower 

Miocene beds of Kern River. 

Pleurotoma (Clathurella) dumblei n. sp. 

Plate XV, Figs. 60 and 61. 

Shell small or medium in size, i-ij^ inches long; spire high; whorls 6 or 
more, convex; aperture simple, ovate, inner lip uncalloused; canal very 


short; surface ornamented by strong spiral and longitudinal lines, giving a 
cancellated sculpture. 

Occurrence. — This species occurs abundantly in the Lower 
Miocene beds of Kern River, 

Bullia (Molopophorus) anglonana n. sp. 

Plate XVI, Figs. 74-76. 

Shell moderate in size, i inch in length, % inch in width; spire moderately 
elevated; aperture broad, lip simple, notched above; columella crusted, 
whorls angulated, bearing tubercular, or spinose nodes above, and on lower 
part of body whorl; surface ornamented with lines of growth, and with 
revolving lines, strongest on the lower portion of the body whorl. The 
anterior notch is deep, and bordered by 2 strong folds which extend upward, 
revolving obliquely around the columella, forming a wide canal, shown 
only in figure 74. 

This species is somewhat related to B. striata Gabb, from 
the Tejon Beds, but more nearly related to undescribed 
species occurring in the so-called Oligocene Beds of Oregon. 

Occurrence. — This species occurs not rarely in the Lower 
Miocene beds of Kern River. 

Fusus (Hemifusus) wilkesana n. sp. 

Plate XVI, Figs. 81 anu 82. 

Shell moderate in size, robust, tapering rapidly below; spire moderately 
elevated, angulated, with tubercular nodes on the angles of the whorls; sur- 
face strongly marked by spiral lines and longitudinal ridges, especially 
prominent at and below the angles of the whorls; canal only moderately 
prolonged; open; columella somewhat curved. 

This species seems to be related to, and is possibly iden- 
tical with Fiisus corpiilentus Conrad, from the Miocene beds 
of Astoria, Oregon; but as Conrad's figure was drawn from 
a cast, it is not possible to establish its identity with the 
species described here. 

Occurrence. — The Lower Miocene beds (Temblor Beds) 
at the Kreyenhagen oil wells. Kings County. 


Chorus carisa'ensis n. sp. 

Plate XVII, Figs. 90 and 91. 

Shell rather large and thick, strongly spinose, and oblique; spire moder- 
ately high, sloping above; body whorl narrowing rapidly below; aperture 
large, triangular, bearing a stout tooth on the outer lip near the upper end 
of the canal; canal narrow, short, and strongly recurved; columella crusted 
and strongly recurved; surface marked only by strong lines of growth. 
There are about 8 strong spines on the angles of each whorl, excavated in 
front and conve-x behind. 

Occurrence. — This shell is common, though not plentiful in 
the lower Etchegoin Beds of the Mount Diablo Range, near 
La Panza Springs, San Luis Obispo County. 

California Academy of Sciences, 
July 31, 1905. 





nodosaria 193 

Figs. 9-15. 

Lagena (?) 193 

Fig. 16. 

Sagrina i^:^ 

Figs. 17-18. ,♦ . 

Vaginulina 193 

Fig. 19- 


Figs. 20-22. 


Fig. 23. 


Figs. 24-29. 


Cassidulus californicus n. sp. I94 

Figs. 6-7. 
Scutella sp. A. n. sp. i93 

Fig. 8. 


Spondylus carlosensis n. sp. I94 

Fig. I. 
Ostrea avicidijormis n. sp. I94 

Figs. 3-5- 
Cypraea fres7ioensis n. sp. 198 

Fie. 2. 

FHDC.CAUACAD.SCI.a^ Seh. Gedl Vdl.II. 

[Aniiersdn] Vlkte nil. 


20 21 



29 28 






Bmmi.-iziH.HHrrTaN s sey. bt; 



Cyrena {Corbiaila) duinblein. sp. 195 

Figs. 30-32. 
Astrodapsis nierriami n. sp. 193 

Figs- 33-34. 
Venus {Chiofie) couradiatia n. sp. 195 

Fig- 35. 
Venus {C/iione) temblorensis n. sp. 196 

Figs. 36-38. 

FHnc.CAL.AcAi]^ Sci 3° See. GedlVdl.1I. 

AnderbqnI Plate XIV 



™CTn .-IjrH. ±W 11 1 OK SHEY. GT. 



Cancellaria dalliana n. sp. 199 

Figs. 39-42. 
Cancellaria pacifica n. sp. 199 

Figs. 43-45- 
Cancellaria joaqiiinensis n. sp. 199 

Figs. 46-48. 
Cancellaria condoni n. sp. 200 

Figs. 49-50- 
Cancellaria simplex n. sp. 200 

Figs. 51-52. 
Oliva fiUheyana n. sp. 201 

Fig. 53- 
Oliva calif ornica n. sp. 201 

Figs. 54-55- 
Scaphander jttgularis Conrad 201 

Figs. 56-57. 
Conns oweniana n. sp. 201 

Figs. 58-59- 
Pleurotoma {Clalhurella) dumbleiw. sp. 204 

Figs. 60-61. 
Purpura lima Martyn. 202 

Figs. 62-63. 


[Anders dn] Viate XV. 

u \ * V\vA 




.•ji.'-ji r W^ 

^^ =m 





' 61 

50 {y^ 

63 W^C^j' 






Trophon kernensis n. sp. 202 

Figs. 64-65. 
Trophon gabbiana n. sp. 203 

Figs. 79-80. 
Terebra cooper i n. sp. 203 

Figs. 66-67. 
Sigareius scopulosus Conrad. 203 

Figs. 72-73. 
Nassa arnoldi n. sp. 204 

Figs. 70-71. 
Crepidiila praeriipta Conrad. 204 

F"igs. 68-69. 
Bullia {Molopophoriis) anglonana n. sp. 205 

Figs. 74-76- 
Cancellaria vespertina n. sp. 200 

Figs- 77-78- 
Fusus {Heniifusus) wilkesana n. sp. 205 

Figs. S1-S2. 

FRnc.CAL.ACAD.Bci. 3^ 5er.GedlVdl.II. 

[Anders dn] Plate XVI. 



■pHaio.-iim.BHrrraK * hey. b.t 



Cytherea {Callisia) diablo'ensis n. sp. 196 

Figs. 83-85. 
Pectuiicuhis septcntrionalis Miudknuorf. 197 

Figs. 86-S7. 
Diplodoiita harfordi 11. sp. 197 

Figs. 88-89. 
Chorus carisaensis n. sp. 206 

Figs. 90-91. 


[Anderbdn] PIATE XVll. 



XfJSr wmjMAH. DEL 

. H oHlil U N «r HEY. BT 



Pec ten etchegoini n. sp. 198 

Figs. 92-93- 
Pecten coalingaensis Arnold. i97 

Figs. 94-98. 

FHnc.CAL.ACAD 5ci.3^ Ser. GedlVql.IL 

[ANnERSDN] Plate J^flll 

^. \ 


iv«r wellman.hel. 

fflDio.-iim.BHrrToii »hey. et. 



View near Stone Canyon, showing Franciscan rocks and topography; 
radiolarian jaspers in the foreground. 



View showing hard siliceous Franciscan rocks in an area of serpentine; 
Mount Carlos. 



View showing eruptive rocks (basalt ?) within an area of Franciscan; Lewis 
Creek, Monterey County. 

^— wir^p-ip-^^^jpii 



View showing stratigraphic series near New Idria; Cretaceous strata on 
left and right, Eocene in middle distance, Neocene in the distance. 



V'lQw on Warthan Creek; Franciscan rocks in the foreground, Cretaceous in 
the distance, Monterey Shales on the left. 


View on Los Gatos Creek, showing upturned Cretaceous strata. 



'• • T 





;* * 

^ w.» 



View five miles north of Temblor, showing massive Eocene rocks in fore- 
ground, overlain unconformably by Temblor Beds. 







R ■ 

I — r 





View four miles north of Temblor, showing unconformity between Temblor 
Beds and the underlying Eocene, dipping in opposite directions. 







R ■ 


I — I 






View on north side of Antelope Valley, showing weathering of Eocene 



View south of Warthan Creek, at summit of range, showing Temblor Beds 
dipping northerly; F"ranciscan rocks on extreme left. 



View on summit of range south of Warthan Creek, showing Temblor Beds 
dipping south, overlain by Monterey Shales, seen on the left. 



View on south side of Warthan Creek, showing Monterey Shales dipping 
northerly; PVanciscan rocks in the foreground and to the left. 



View eight miles north of Coalinga, showing Monterey Sliales, Coalinga 
Beds, and Etchegoin Beds successively, from right to left. 







) — I 






View eight miles north of Coalin'ga, showing Etchegoin Beds dipping 



View eight miles north of Coalinga, showing disturbance of Coalinga Beds 
overlying Monterey Shales; Reef Bed seen at center, extreme right, 
and extreme left, above. 








n ■ 

( — I 






1 . Frof//e Sect /'on a/ /I /en a I 











^^— -^ 



'l./'rofiU Section at Coal Mine wes. 



.•J. frofile Section S Mi/es /lortA of 

[Anderson] Rate XXXIV 




.\\\\A\ \ > \\\\\\\\v\ v.V.v.\\\\\w.\ A \ ■ 


P/ioce/>e (£tc/!e^oi/?J 

7s , /^///gs County, Ca///or/)/s. 


P/(OCe/ie (^£te/>esoini 

of Co^/iaga , fresno County , Cdtifor/ji'g. 


F/iocene (£tchegocn) 

•a/ins& , /y-es/70 County, Ca/ifor/fia . 


Third Series 

Vol. I 

No. I — The Geology of Santa Catalina Island. By William Sidney 

Tangier Smith .-. % .50 

No. 2 — The Submerged Valleys of the Coast of California, U. S. A., 

and of Lower California, Mexico. By George Davidson... .50 
No. 3 — The Development of Glyphioceras and the Phylogeny of the 

Glyphioceratidje. By James Perrin Smith 35 

No. 4 — The Development of Lytoceras and Phylloceras. By James 

Perrin Smith 35 

No. 5 — The Tertiary Sea-Urchins of Middle California. By John \ 

C. Merriam f 

No. 6 — The Fauna of tlie Sooke Beds of Vancouver Island. By i 

John C. Merriam ' 

No. 7 — The Development and Phylogeny of Placenticeras. By James 

Perrin Smith 50 

No. 8 — Foraminifera from the Tertiary of California. By Frederick 

Chapman 25 

No. 9 — The Pleistocene Geology of the South Central Sierra Nevada 

v.,'ith Especial Reference to the Origin of Yosemite Valley. 

By Henry Ward Turner 50 

No. 10 — The Comparative Stratigraphy of the Marine Trias of West- 
ern America. By James Perrin Smith i.oo 

Vol. II 

No. I — Cretaceous Deposits of the Pacific Coast. By Frank I\I. 

Anderson fi-75 

No. 2 — A Stratigraphic Study in the Mount Diablo Range of Cali- 
fornia. By Frank M. Anderson 1.25 

See page 130 for index to the Cretaceous Deposits of the Pacific Coast. 

New names in heavy-faced type; Synonyms in italics. 

Agasoma gravidum, 172, 183, 186, 187, 

kemianum, 176, 185, 188 

sinuatum, 188 
Amauropsis alveata, 164, 166 
Ammonites (Hoplites), 161 
Amnicola turbiniformis, 182 
Ancellaria elongata, 164 
Anodonta decurtata, 182 

nuttaliana, 182 
Area (Barbatia) morsei, 166 

montereyana, 172, 176, 185, 188 

trilineata, 179, ISO 
Architectonica horni, 164 

specie?, 161 

merriami, 171, 172, 193 

tumidus, 176, ISO, 181 

species, 177, 183 
Baculites chicoensis, 161 

species, 161 
Ballanus, species, 170, 171, 172, 180 
Belemnites, 161 
Bulla jugularis, 201 
Bullia (Molopophorus) anglonana, 188, 

Bullia striata, 205 
Callista, species, 173 
Cancellaria condoni, 188, 200 

dalliana, 188, 199 

granosa, 199 

joaquinensis, ISS, 199 

oregonensis, 200 

pacifica, 199 

simplex, 188, 200 

urceolata, 200 

vespertina, 177, 200 

species, 176 
Cardita, 165 
Cardita horni, 164, 166 

species, 164, 166 
Cardium cooperi, 164, 166 

meekianum, 179, 180 
Carinifex newberrvi, 182 
Cassidulus califomicus, 166, 193 
Chama, species, 180 
Chione, 176 

guidia, 196 

mathewsoni. 170, 186 
Chorus carisaensis, 206 
Chrysodomus recurva, 177 

species, 180 

Cinulia obliqua, 161 

Clypeaster (Scutella) breweriana, 180 

Conus californica, 202 

oweniana, 187, 201 
Corbula paralis, 164 
Crepidula excavata, 177 

grandis, 187 

praerupta, 171, 187, 188 
Cuma biplicosta, 188 
Cyclammina, 193 
Cypraca fresnoensis, 198 
Cyrena (Corbicuba) dumblei, 188, 195 

californica, 177 
Oytherea (Callista), species, 176, 177 
Cytherea callosa, 196 

diabloensis, 177, 196 

mathewsoni, 187, 188 

species, 188 
Dentalium cooperi, 164 

substriatum, 188 

species, 188 
Desmoceras, 161 

hoffmanni, 161 
Diplodonta harfordi, 175, 176, 177, 180 

orbella, 197 
Discohelix, 165 

Dosinia mathewsoni, 170, 171, 186, 187, 

ponderosa, 176, 177 

species, 166, 187, 188 
Echinodermata, 193-4 
Ellipsosmilia granulifera, 166 
Foraminifera, 192-3 

Fusus (Hemifusus) wilkesana, 1S7, 205 
Fusus corpulentus, 205 

diaboli, 164 

martinez, 164, 166 
Galcms excentricus, 166 

species, 177 
Gari texta, 166 
Gasteropoda, 198-206 
Glycimeris estrellanus, 187 

septentrionalis, 197 
Goniobasis occata, 182 
Gyrodes, species, 161 
Hemifusus wilkesana, 172, 205 

species, 176 
Hinnites, species, 180 
Homomya, species, 188 
Inoceramus, 161 

whitneyi, 161 




Lagena (?), 193 
Lamellibranchiata, 194-8 
Lamna clavata, 177 
Leda oregona, 173, 188 
Lucina acutilineata, 172 

borealis, 170, 176, 17"^ 

richthofeni, 170, 187 88 

species, 172 
Lunatia horni, 166 
Lytoceras sacya, 161 
Macoma nasuta, 176, I'l ) 

secta, ISO 

species, 170 
Mactra (Spisula), species, 172 
Mactra catilliformis, 177 

falcata, 176, 177, 180, 181, 188 

densata, 172, 180 

species, 166, 183, 188 
Margaritana subangulata, 182 
Meretrix horni, 164, 166 

uvasana, 165, 166 
Metis (Lutricola) alta, 177, 180 
Modiola ornata, 166 
Morio tuberculatus, 166 
Mulinia densata, 184 
Mya arenaria, 179 
Mytilus californianus, 176, 177 

mathewsoni, 170, 186, 187 

species, 179 
Nassa arnoldi, 188, 204 

californica, 180 

perpenguis, 204 

species, 177, 180 
Natica, species, 172, 180 
Nerita triangulata, 166 
Neverita callosa, 170, 171, 172, 187, 188 

globosa, 164, 165, 166 

recluziana, 176, 177, 180 
Nodosaria, 193 
Oliva californica, 1S7, 188, 201 

futheyana, 201 
Ostrea attwoodi, 179 

aviculiformis, 166, 194 

idriaensis, 165, 166 

sellaefonnis, 195 

species, 176 
Oxyrhina tumula, 177 
Pachydesma inezana, 188 
Pesten coalingaensis, 179, 180, 197 

crassicardo, 171, 180, 181 

discus, 169, 171, 172, 176, 177, 
185, 188 

estrellanus, 172, 176, 177, 187 

etchegoini, 180, 198 

nevadensis, 169, 187 

oweni, 180 

pabloensis, 181 

peckhami, 169, 173 

wattsi, 180, 198 

species, 166, 170, 183, 187 
Pectunculus scptentrionalis, 179, 180, 

181, 197 

veatchi, 161 

species, 188 
Perissolax brevirostris, 161 
Physa costata, 182 
Placuanomia inornata, 166 
Planorbis tumens, 182 
Pleurotoma (Clathurella) dumblei, 188, 

Pleurotoma (Surcula), species, 180 
Polymorphina (?), 193 
Pomatiopsis intermedia, 182 
Pseudocardium gabbi, 179, 184 

species, 176, 180 
Pulvulina, 193 
Purpura, species, 177 
Sagrina, 193 

Saxidomus aratus, 180, 181 
Scaphander jugularis, 187, 188, 201 
Scutella gibbsi, 180, 181 

species, 166, 171, 179, 183, 193 
Sigaretus planicostum, 204 

scopulosus, 188, 203 
Sinum scopulosum, 203 
Solen paralellus, 164 

sicarius, 188 

species, 170, 176, 188 
Sphaerium dentatum, 182 
Spondylus carloaensis, 165, 166, 194 
Tamiosoma, 176 
Tapes staleyi, 180 

tenerrima, 176, 177 

species, 170, 172 
Tellina congesta, 173 

ocoyana, 188 

species, 106. 180, 188 
Terebra cooperi, 188, 203 

wattsiana, 203 
Terebratella, 165 

species, 166, 180 
Trochita filosa, 187, 188 

species, 176 
Trochosmilia striata. 166 
Trophon gabbiana, 176, 203 

kernensis, 18.8, 202 

ponderosum, 180, 202, 203 

species, 176, 177 
Turritella hofFmanni, IRS 

ocoyana, 171, 172, 183, 187, 188 

pachecoensis, 164, 166 

uvasana, 164, 165, 166 

species, 176 
Vaginulina, 193 
Venus (Chione) conradiana, 195 

pertenuis, 195 

temblorensis, 172, 188, 196 
Venus (Mercenaria) pertenuis, 188 
Yoldia cooperi, 170 

impressa, 188 
Zirphaea dentata, 176, 177 

species, 172 
Zygobates, species, 177 

3 2044 103 22 

Date Due