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MEMOIRS

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SAN DIEGO SOCIETY OF NATURAL HISTORY

Volume II

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THE GEOLOGY AND PALEONTOLOGY
OF THE MARINE PLIOCENE OF
SAN DIEGO, CALIFORNIA

PART 1, GEOLOGY

BY

LEO GEORGE HERTLEIN

California Academy of Sciences
AND

U. S. GRANT, IV
University of California at Los Angeles

PUBLISHED WITH AID OF A GRANT
FROM THE
ELLEN BROWNING Scripps FOUNDATION

SAN DIEGO, CALIFORNIA
PRINTED FOR THE SOCIETY
Aucust 30, 1944

MEMOIRS

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SAN DIEGO SOCIETY OF NATURAL HISTORY

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MEMOIRS

OF THE

SAN DIEGO SOCIETY OF NATURAL HISTORY

Volume II

THE GEOLOGY AND PALEONTOLOGY
OF THE MARINE PLIOCENE OF
SAN DIEGO, CALIFORNIA

PART 1, GEOLOGY

BY

LEO GEORGE HERTLEIN

California Academy of Sciences
AND

U. S. GRANT, IV
University of California at Los Angeles

PUBLISHED WITH AID OF A GRANT
FROM THE

ELLEN BROWNING Scripps FOUNDATION

SAN DIEGO, CALIFORNIA
PRINTED FOR THE SOCIETY
Aucust 30, 1944

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Introduction

CONTENTS

~ Historical Review of the Literature of the San Diego Formation

Rhy stOera pny: anc 2 otc eng there

General Description .....
Climate and Rainfall .
The Coastal Mesa Region
The Terraces . !
San Diego Mesa
Younger Terraces
Older Terraces
Shoreline Features...
The Peninsular Mountains
Stream Valleys and Drainage
Coastal Mesa Region
Peninsular Mountains
Physiographic History
General Relationships to Other Regions

Pre-Tertiary Igneous and Metamorphic Rocks

Cretaceous

Eocene

Absence of Oligocene and Miocene Rocks in the San Diego Region

Pliocene -

Distribution .

Lithology and Sedimentation

Pacific Beach and Soledad Mountain
San Diego Mesa

Structure

Age and Correlation

The Sweitzer Formation

Origin of the Sweitzer Formation

Pleistocene .

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THE GEOLOGY AND PALEONTOLOGY
OF THE MARINE PLIOCENE OF
SAN DIEGO, CALIFORNIA

BY
LEO GEORGE HERTLEIN AND U. S. GRANT, IV

PART 1, GEOLOGY
INTRODUCTION

The chief object of this memoir is to describe and illustrate the marine Pliocene invertebrate fauna
of the environs of San Diego,’ California. The present paper contains a geological introduction
consisting of a review of the literature and a brief account, largely descriptive, of the general geological
and physiographic features present in the region from which the fossils were obtained, including also
some of the contiguous area north and east. No attempt has been made to prepare an exhaustive report
on the geology and physiography of the region, but it is hoped enough has been given to form a geologic
setting for the stratigraphic study and for a comprehension of some of the conditions which effected
the deposition of the Pliocene sediments and the distribution and occurrence of the species enumerated
later on.

The field work upon which the geologic and stratigraphic portions are based, and which has
resulted in the accumulation of large collections of fossils, was begun in 1926 when the region was
visited by Eric Knight Jordan and Hertlein. Some collections were made and notes taken but the
work had hardly begun when it was interrupted by the lamentable death of Mr. Jordan. The present
authors resumed field work in 1927 and 1928, and both of them, or one or the other, have made
several later trips, particularly in 1937, to supplement the collections or obtain new information on
the geology and stratigraphy. The laboratory work was done largely at the University of California
at Los Angeles and at the California Academy of Sciences, although occasionally certain investigations
were carried out at Stanford University, the University of California at Berkeley, and at the Museum
of the San Diego Society of Natural History. The somewhat belated appearance of this paper is due
in large part to the preoccupation of both authors with their other duties, the work having been done
during such spare time as only occasionally became available.

It was originally planned to have the complete memoir issued at one time, but the limited and
somewhat indefinite periods during which both the authors could devote their entire attention to
bringing the manuscript up to date, and later reading the proofs, made its separation into parts
necessary. The present part containing only the geological and general introductory matter will be
followed by the several parts containing the systematic paleontology and it is proposed, in a final part,
to include a discussion of the age and significance of the fauna as a whole and its correlation
with that of other marine Pliocene formations in western North America.

Without the assistance of a number of persons this report could not have been prepared in its
present form, and this occasion is taken to offer grateful acknowledgment of assistance received from
them. Later special acknowledgment will be made of assistance received while working on the
paleontologic parts. The late Mr. Frank Stephens, veteran naturalist of San Diego and former
Curator Emeritus of the Museum of the San Diego Society of Natural History, was of great assistance
to us during the field work. He accompanied us during the beginning of the field work and saved
us much time in pointing out important fossil localities, some of which would have been difficult to
discover or might have been overlooked entirely. Mrs. Kate Stephens of the same institution, now
retired, assisted in a similar manner by calling attention to the occurrence of important species in
certain parts of the region, and also prepared for us a large list of Pleistocene fossils from Spanish
Bight. Mr. Eric Knight Jordan assisted during the initial stage of the field work, as related above.

' For an excellent compilation of the general facts concerning the history and features of San Diego, Calif., see, “San Diego,
A California City”, Amer. Guide Series (sponsored and publ. by The San Diego Historical Society, San Diego, Calif.), x + 138
pp., frontispiece, 25 illustrations, 6 maps, 1937.

10 San Dreco Society oF Naturat History [Memotrs

Messrs. Frank B. Tolman and Ernest H. Quayle assisted us materially by collecting large faunas
and pointing out some interesting geological features. Mr. Tolman gave helpful advice in regard to
the Eocene stratigraphy, and Mr. Quayle has spent much time in assisting us with the illustrations.
Dr. John E. Wolff, Professor of Geology Emeritus at Harvard University, prepared a short description
of several crystalline rocks, and Dr. Gordon A. Macdonald, now of the U. S. Geological Survey,
made some interesting petrographic and sedimentary studies for us. The Associated Oil Company
permitted the use of well logs of this area which Mr. C. C. Church, paleontologist of that company,
kindly examined for us. We here wish to acknowledge the cooperation of Mr. J. E. Pettijohn who
kindly permitted us to examine the geologic reports of Mr. George H. Doane on the San Diego Gas
and Petroleum Corporation’s Holderness No. 1 Well, which was drilled near the mouth of the Tia
Juana River. Mr. Clinton G. Abbott, Director of the Museum of the San Diego Society of Natural
History, permitted us to use all the facilities of that institution and cooperated in an important manner
during the publication of the paper. Dr. G. Dallas Hanna of the Department of Paleontology,
California Academy of Sciences, aided us many times with his valuable advice and cooperation. Both
authors began this work while students of the late Dr. James Perrin Smith, Professor of Paleontology
at Leland Stanford Jr. University, and they both remember his kind encouragement at that time. We
wish to express our appreciation to Dr. Olaf P. Jenkins, Chief Geologist of the Division of Mines of
the State of California, and to Mr. A. L. Ransome and Mr. E. Drew of the same department, for
advice and assistance in the preparation of the geologic map and sections. Mr. F. P. Farquhar kindly
furnished information regarding the construction of the first dike at San Diego by Derby. Secretarial
work on the manuscript by Miss Winifred O’Neill is the result of work accomplished during a
government Works Progress Administration Project No. 8569. The authors are grateful for the
research grants from the University of California at Los Angeles received during the progress of
this work.

HISTORICAL REVIEW OF THE LITERATURE

The sedimentary beds in the vicinity of San Diego have been mentioned or briefly described by
many authors. Most of the early reports were brief notes based upon limited field observations or
were mere descriptions of or references to some of the fossils that occur there. Tyson,” who made a
short trip to San Diego about 1850, mentioned “that sedimentary rocks prevailed on the hills near
the sea, and that there was an extensive diffusion of diluvial drift.” T. A. Conrad’s description’ of
Ostrea vespertina from “near San Diego, California,” seems to have been the first paleontologic notice
of the fossiliferous sedimentary beds in that region. In this paper, he referred the beds containing this
Pliocene oyster questionably to the Miocene and in three later papers* he also considered these beds
to belong to the Miocene. In 1856, William P. Blake,’ a pioneer geologist of the West, referred briefly
to the general features of the region about San Diego and included with his report a small scale
geologic map of southern California. He also mentioned certain fossils which he believed to be of
Miocene age but which are now known to be of Eocene age. In two subsequent papers he likewise
mentioned Tertiary fossils, probably the Eocene fossils which occur plentifully near the older part of
the City of San Diego, near the San Diego Mission, and at various other localities. The Tertiary beds
in the vicinity of San Diego were also mentioned by Antisell.°

In connection with the survey of the United States-Mexican Boundary made about the middle of
the last century, Emory’ made a limited study of the geology in the vicinity of San Diego and briefly
described the seaward dipping sedimentary beds of “coarse sand, clay, or marl, with occasional beds

2 Tyson, P. T., “Geology and Industrial Resources of California,” Senate Executive Document 47, 31st Congress, Ist Session,

1850 (reprinted with an introduction, published by Wm. Minifie and Co., Baltimore, 1851), p. 20. See also Lieut. E.O.C. Ord, p. 123.

> Conrad, T. A., Journ. Acad, Nat. Sci. Philadelphia, Ser. 2, Vol. 2, p. 300, 1854.

4 Conrad, T. A., House Document 129, Projected Vol. 3, 33rd Congress, Ist Session, 1855, pp. 11-18. U. S. Pac. R. R
Repts., Vol. 5, pp. 322-327, 1856-1857. — Rept. U. S. Boundary Surv., Vol. 1, pt. 2, p. 160, 1857.

5 Blake, W. P., Senate Ex. Doc. 22, 34th Congress, Ist Session, Rept. Supt. Coast Surv., pp. 395-396, Map 60, 1855
(issued 1856). Proc. Amer. Assoc. Adv. Sci., Vol. 9, p. 224, 1856. U. S. Pac. R. R. Repts., Vol. 5, pp. 176-177, 1857.

6 Antisell, T., U. S. Pac. R. R. Repts., Vol. 7, p. 119, 1856.
7 Emory, W. H., Rept. of U. S, Boundary Surv., Vol. 1, pt. 2, p. 85, 1857.

VotumE IT] MarINE PLIOCENE OF SAN DrkEGO, CALIFORNIA 11

of interstratified pebbles” and noted particularly a thirty foot fossiliferous layer exposed in the steep
bluffs which bound the lower part of the river valley at San Diego. This layer may have been the
fossiliferous Eocene exposed on the sides of San Diego River Valley though on the south side the
overlying Pliocene is likewise fossiliferous. This may be said to have ended the period of pioneer
geological work during which much important information of a reconnaissance nature of various parts
of California was obtained, largely in connection with the expeditions sent out by the War Department
to make surveys for proposed railroad routes in what was then referred to as the “far West.”

Years later, after the business district of San Diego had moved from its former position (now
called “Old Town”), near the mouth of San Diego River Valley,* to a position several miles south on
the shore of San Diego Bay, a well was dug in the bottom of a small canyon back of the City in
order to obtain water to supplement the meager supply for the small but rapidly growing settlement.
This well, which was in City Park (now Balboa Park), penetrated a fossiliferous fine-grained sandstone
from which Henry Hemphill, an early local conchologist, obtained a considerable collection of fossil
shells. Part of this collection was sent to the late W. H. Dall who published a paper? in 1874 in which
he discussed the “San Diego beds” and listed 51 definitely identified species and eighteen additional not
specifically identified forms. He made the following comment as to the geologic age:

“The age of the deposit, in general terms, may be taken as Pliocene; though it is evident that the
different epochs of the Tertiary are not as sharply separated on this coast as in some other parts of
the world.”

A few years later Dall’® again listed the fauna from the San Diego well and added the descriptions
of six new species. He noted Hemphill’s suggestion of the equivalence of the beds in the well from
which the fossils were obtained, to the fossiliferous beds at Pacific Beach several miles to the northwest.
Dall again gave the age as Pliocene.

In 1886 a note in the West American Scientist,'' presumably by its editor, C. R. Orcutt, stated :

“The peninsula in front of San Diego city is being improved by a company who propose making
it a popular resort and to which the name Coronado Beach has been applied. In boring for Artesian
water, a strata [stratum] of sand was found containing numerous fossil shells of the later tertiaries.
The most prevalent species were Phasianella compta, Ostrea lurida and Anomia lampe in the order
named. The strata was found at a depth of nearly seventy feet.” This occurrence was mentioned by
Ellis,'* who stated that W. A. English regarded the three species as belonging to the lower Pliocene.
However Tricolia compta Gould is not definitely known below the Pleistocene and the other two species
are much more common in the Pleistocene than in the Pliocene, hence it is almost certain that the
beds encountered in this well are of Pleistocene age.

In a catalogue of California fossils, published in 1888, ]. G. Cooper'’ listed numerous species
from the Pliocene of San Diego, some of them being reported for the first time in those beds. In the
same year Goodyear’ discussed the geology of San Diego County in which paper the following
statement occurs :

“Commencing at the Mexican boundary line, the Mesa formation, of pleiocene age, is some ten
or twelve miles wide, and from thence it forms an uninterrupted belt of varying width for a distance
of more than fifty miles along the coast towards the northwest, or as far as the Santa Margarita River.”
It is apparent that Goodyear included beds other than the Pliocene, for most of the mesa north of

‘i 8 Often known as Mission Valley but not to be confused with a Mission Valley further north in the San Luis Rey River
Valley.

9 Dall, W. H., Proc. Calif. Acad. Sci., Vol. 5, pp. 296-299, 1874. According to Henry Hemphill, the collector, the
fossils were obtained from the well at a depth between 140 and 160 feet. The matrix was said to be hardly consolidated in some

parts and quite hard in others. The occurrence of these fossils was first mentioned by R. E. C. Stearns (Proc. Calif. Acad. Sci.,
Vol. 5, no. 10, pp. 153-55, Oct., 1873).

10 Dall, W. H., Proc. U. S. Nat. Mus., Vol. 1, pp. 10-16, 26-30, 1878.
11 Orcutt, C. R., West Amer. Scientist, Vol. 2, no. 15, p. 32, 1886.
12 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, p. 64, 1919.

'3 Cooper, J. G., Calif. State Mining Bureau, 7th Ann. Rept. State Mineralogist, pp. 223-308, 1888. Parts 2, 3, 4 and 5
of this catalogue appeared as Bulletin 4, Calif. State Mining Bureau, 65 pp., 6 pls., 1894.

14 Goodyear, W. A., Calif. State Mining Bureau, 8th Ann, Rept. State Mineralogist, p. 522, 1888.

12 San Disco Socrety oF Naturat History (Memoirs

San Diego River Valley is of Eocene age.

In 1889 Orcutt!’ published a list of Tertiary fossils from localities such as Pacific Beach, False
Bay (now called Mission Bay), Ocean Beach and Roseville, but he added nothing new on correlations.
Some of the localities are probably Pleistocene. At Pacific Beach Orcutt noted three imperfectly defined
members. The oldest he stated was.a sandstone with moulds of various bivalves and imperfect valves
slightly resembling oysters; the second, distinctly softer beds, containing Opalia, Janira, Pecten,
Terebratula?; the third, younger beds more recent in character, containing most of the other species.
Probably his oldest bed was Eocene, the second Pliocene, and the third either Pliocene or Pleistocene.

A number of the West American Scientist for 1900 (Vol. 10, no. 4, whole no. 86, pp. 17-19),
contains a discussion of the geology of the San Diego region by H. W. Fairbanks. Some of the
structural features are mentioned and particular mention is made of the changes in elevation which
took place in the late Tertiary and Quaternary. Fairbanks mentioned a “Mesa formation” which no
doubt included the Pliocene beds. This discussion in the West American Scientist appears to be a
quotation from the San Diego Sun of April 16, 1891.

A paper on correlation by Dall and Harris'® was published in 1892, in which they gave a brief
review of the existing literature concerning the San Diego region and quoted Dall’s original
determination of the Pliocene age of the fossils from the San Diego well.

At this time some of Fairbanks’ geological work for the California State Mining Bureau was
being published. In one paper’” he discussed the geology in the vicinity of San Diego and referred to
strata of Quaternary, Pliocene and questionably Miocene age. He gave a good outline description
of the basin in which the San Diego beds were deposited and stated that apparently Point Loma and
the Soledad Hills formed the western and the northern margins of the basin. He also pointed out that
a recent uplift had taken place along the ocean side of the mesa. In a second paper'® he stated:

“The Miocene is not positively recognized near San Diego, but the mesas along the eastern side
of the bay on which the city is situated are filled with Pliocene fossils; the strata being separated from
the Chico-Tejon by a small non-conformity.”

In 1893 an important paper’? on the post-Pliocene diastrophism of the coast of southern California
by A. C. Lawson was published. This paper contains an excellent description and discussion of the
marine terraces in the San Diego region. Lawson believed the San Diego beds to be in part a portion
of a delta of Pliocene age, the age determination being based upon a comparison with Miocene strata
elsewhere and upon Dall’s paleontologic evidence. .

A number of later papers have contained indirect references to the San Diego beds in connection
with correlations of other deposits on the Pacific coast. Among these may be mentioned papers by
Dall,?° Arnold,”' Rivers,” J. P. Smith,’* Louderback,** Merrill”? Clark and Twitchell,*° Moody,””

15 Orcutt, C. R., West Amer. Scientist, Vol. 6, whole no. 45, pp. 70-71, 1889.

16 Dall, W. Hi, and Harris, G. D., U. S. Geol. Surv., Bull. 84, p. 216, 1892.

17 Fairbanks, H. W., Calif. State Mining Bureau, 11th Ann. Rept. State Mineralogist, 1891-1892, pp. 96-97, 1 map, 1893.

18 Fairbanks, H. W., Amer. Journ. Sci., Ser. 3, Vol. 45, p. 477, 1893. A year later Cooper stated that the fossils found
by Fairbanks indicated that the whole mesa was of Pliocene age. See Calif. State Mining Bureau, Bull. 4, p. 52, 1894.

19 Lawson, A. C., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 1, pp. 115-160, pls. 8, 9, Dec., 1893. See page 119

20 Dall, W. H., U. S. Geol. Sury., 17th Ann. Rept., pt. 1, p. 476, 1895. In this paper Dall reported fossils collected by
Diller in northwestern Oregon, stating that some of them belonged to “‘the Pliocene (horizon of Pacific Beach, San Diego, Cal.).”

21 Arnold, R., Mem. Calif. Acad. Sci., Vol. 3, pp. 13, 57-64, 1903. — U. S. Geol. Surv., Prof. Paper 47, p. 28, 1906.

22 Rivers, J. J., Bull. Southern Calif. Acad. Sci., Vol. 3, no. 5, p. 69, 1904. Rivers mentioned sandstones in the Santa
Monica Mountains which he believed represented the San Diego Pliocene in that area.

23 Smith, J. P., Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, no. 4, pp. 149, 151, 1919.

24 Louderback, G. D., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 7, no. 10, p. 223, 1913. This paper contains a correlation
table of west coast Tertiary formations, in which the San Diego formation is considered equivalent to the Purisima formation of
central California, since reference is made to “Sandstones of San Diego and Half Moon Bay with Pecten healeyi.” Trans. San
Diego Soc. Nat. Hist., Vol. 2, no. 3, pp. 87-97, 1916.

25 Merrill, G. P., Calif. State Mining Bureau, 14th Ann. Rept., pt. 5, pp. 639-644, 1916. Issued as a separate, Dec., 1914.
Contains a correlation table and discussion of the geology of the San Diego region.

26 Clark, W. B., and Twitchell, M. W., U. S. Geol. Surv., Monograph 54, p. 102, 1915. In a correlation table the San
Diego formation is placed below the Merced and given as equivalent to the Caloosahatchee and Nashua of the eastern Gulf area,
and the Waccamaw of the south and middle Atlantic border.

27 Moody, C. L., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 10, no. 4, p. 50, 1916

VotuME II] MarINE PLIOCENE OF SAN D1EGo, CALIFORNIA 13

B. L. Clark,?* Kew,2’ Carson,’ Hertlein,’’ E. K. Jordan and Hertlein,*? Waterfall,’* Pressler,*
Woodring,” Soper and Grant,*° Reed,” and others.”®

In an important correlation paper Dall” stated that the Pliocene marls in the San Diego well also
occur below the Pleistocene beds at Pacific Beach, along the shores of False Bay and on the Coronado
Peninsula. He stated that the horizon could be recognized at various other localities to the north,
including Deadman Island, Harbor Hill, San Pedro, and also at Todos Santos Bay, Lower California.
In the correlation table Dall placed the San Diego beds below the Merced group and indicated them
to be equivalent to the Caloosahatchee beds of the Gulf States and to the Waccamaw beds of the
Atlantic coast. The latter he considered in general correlative with the Crag beds of England. A few
years later*® he remarked that the only known strictly defined Pliocene marine fauna of California was
that at San Diego. He called attention to the difference between the Pliocene and Recent faunas of San
Diego, and the Pliocene and Recent faunas of northern California and Oregon, many of the San Diego
Pliocene species being known in the living fauna only in the Gulf of California.

Ralph Arnold‘! appears to have been the first to use the name “San Diego Formation” for the
Pliocene strata at San Diego. In his important memoir** on the paleontology and stratigraphy of the
San Pedro region he included the results of his collecting and geological field work in the San Diego
district, including faunal lists of species obtained from several Pliocene and Pleistocene localities—
lists which have been used with little additions or alterations by later writers almost up to the present
time. In a series of important later papers® incorporating the results of his work for the U. S.
Geological Survey he republished the faunal lists of species occurring at San Diego, described new
species from there, or made correlations which mentioned equivalents of the San Diego formation
in other parts of California. Some of his opinions on correlations will be briefly summarized here.
In 1906 he considered the lower part of the San Diego formation to be equivalent to the middle and
upper part of the Purisima formation, and the upper part of the San Diego formation equivalent to
the Merced. In 1907 he considered the Third Street Tunnel (Los Angeles) and Temescal Canyon
(near Santa Monica) faunas to be of “San Diego” age. In. several papers he referred to the middle

28 Clark, B. L., Journ. Geol., Vol. 29, p. 610, 1921. — Proc. First Sci. Confer. Pan-Pacific Union, pt. 3, Bernice P. Bishop
Mus., Special Publ. 7, pt. 3, p. 817, 1921.

29 Kew, W. S. W., Bull. Amer. Assoc. Petrol. Geol., Vol. 7, pp. 419-420, 1923. The Saugus formation of the Ventura
basin believed to be equivalent to the San Diego formation. U. S. Geol. Surv., Bull. 753, p. 89, 1924. Saugus and San Diego
formations believed to be equivalent.

30 Carson, C. M., Pan-Amer. Geologist, Vol. 43, no. 4, pp. 265, 268, 1925. Contains a list of San Diego Pliocene fossils

31 Hertlein, L. G., Proc. Calif. Acad. Sci., Ser. 4, Vol. 14, no. 1, p. 6, 1925. Pliocene of Cedros Island, Lower California,
Mexico, stated to be in general equivalent to the San Diego Pliocene of Pacific Beach.

32 Jordan, E. K., and Hertlein, L. G., Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, no. 14, pp. 422-423, 1926. Relationship
between the Pliocene and Eocene at Pacific Beach clarified and Pliocene of San Diego, Turtle Bay and Cedros Island stated to
represent approximately middle Pliocene or the lower part of the upper Pliocene.

33 Waterfall, L. M., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 18, no. 3, pp. 80-81, April 6, 1929. Upper Pico fauna of
Ventura County correlated with Pliocene of San Diego.

34 Pressler, E. D., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 18, no. 13, p. 334, Sept. 30, 1929.

35 Woodring, W. P., Proc. Calif. Acad. Sci., Ser. 4, Vol. 19, no. 6, pp. 57-64, July 15, 1930. San Diego Pliocene
equivalent noted north of Simi Valley.

36 Soper, E. K., and Grant, 1v, U. S., Bull. Geol. Soc. Amer., Vol. 43, p. 1041-1068, Dec., 1932. See pp. 1066-1067
San Diego Pliocene considered in part equivalent to the Third Street Tunnel beds of Los Angeles, and also in part equivalent <o
the Pliocene of Elsmere Canyon.

37 Reed, R. D., “Geology of California.” Published by Amer. Assoc. Petrol. Geol., Tulsa, Oklahoma, May, 1933. See
pp. 227-228. This important work on the geology of California contains a brief discussion of the San Diego formation.

38 A number of very brief references to the Pliocene of San Diego occur in the literature but need not be included here, since
little new information is contained in them.

39 Dall, W. H., U. S. Geol. Surv., 18th Ann. Rept., pt. 2, opp. p. 334, p. 337, 1898

40 Dall, W. H., in Diller, J. S., U. S. Geol. Sury., Bull. 196, pp. 37-39, 1902.

41 Arnold, R., Journ. Geol., Vol. 10, p. 130, 1902.

42'Arnold, R., Mem. Calif. Acad. Sci., Vol. 3, pp. 13, 57-59, 1903.

43 Arnold, R., U. S. Geol. Surv., Prof. Paper 47, p. 28, 1906. — Proc. U. S. Nat. Mus., Vol. 32, pp. 527, 544, June, 1907

~ In Eldridge, G. H., and Arnold, R., U. S. Geol. Surv., Bull. 309, pp. 23-24, Oct. 23, 1907. — Smithson. Miscell. Coll., Vol
50, pp. 431, 445, Dec. 13, 1907. — In Arnold, R., and Anderson, R. V., U. S. Geol. Surv., Bull. 322, pp. 148, 152, 154, Jan. 4,
1908. — Proc. U. S. Nat. Mus., Vol. 34, pp. 384-385, Aug. 8, 1908. — Journ. Geol., Vol. 17, no. 6, opp. p. 532, 1909. -
U.S. Geol. Surv., Bull. 396, pp. 9, 48, 1909. — In Arnold, R., and Anderson, R. V., U. S. Geol. Surv., Bull. 398, p. 48.
1910. — The correlation table in this paper was also cited by B. Willis in U. S. Geol. Surv., Prof. Paper 71, p. 818, 1912.

14 San Disco Society OF Naturat History {Memoirs

Fernando fauna of the Ventura basin as probably equivalent to the lower part of the San Diego
formation and recognized Pliocene beds of San Diego age, or approximately San Diego age, or
containing species occurring in the San Diego Pliocene and suggestive of similar age, in the Santa
Monica region and in other basins. In 1908 Arnold listed “A gasoma stanfordensis” questionably from
the San Diego formation on Mission Grade, near the head of Sixth Street, San Diego. The Agasoma-
like species which occurs at that locality is a Trophosycon™ in the lower part of the Pliocene beds. In
general, Arnold’s correlations have been but little changed by subsequent work.

Aguilera’ in 1906 mentioned a formation at Tijuana, Lower California, Mexico, which he stated
was the equivalent of the Purisima of California and which he considered to belong at the base of
the Pliocene. This no doubt referred to the southern extension of the San Diego formation on the
south side of the International Boundary.

In 1910 J. P. Smith*® placed the San Diego formation in the lower Pliocene and correlated it
with the middle Fernando of Los Angeles, Ventura, and Santa Barbara Counties, lower and middle
part of the Tulare formation of the San Joaquin Valley, lower and middle part of the Paso Robles
formation at the type section in Salinas Valley, upper part of the Purisima at Half Moon Bay, and
middle part of the Berkeleyan of the Mount Diablo region.

In his later classic paper on the climatic relations of the Tertiary and Quaternary faunas of the
California region, Smith” gave a list of fossil mollusks from the San Diego formation and discussed
the climatic and stratigraphic relations of the fauna to other marine Pliocene faunas of California. He
correlated the San Diego Pliocene with the Merced of Seven Mile Beach (just south of San Francisco)
and considered it to be the southern equivalent of that series. He also stated, following Dall, that
this zone is found in the region of Todos Santos Bay, Lower California. However, beds of that age
have not been reported from near Todos Santos Bay by later workers. It is not known what the original
basis of this age determination may have been. Smith considered the fauna from the City of Los
Angeles described by Moody** to be of the same age as that of the San Diego Pliocene, but it is now
believed that Moody’s fauna is later in age than that of the San Diego formation.” According to Smith
the European equivalents of the San Diego and Merced are the Red Crag of England, Scaldisian of
Belgium, and Astian of Italy.

In a paper’ on the geology and ground waters of the western part of San Diego County, Ellis
included considerable information on the physiography and stratigraphy of the San Diego Tertiary
basin. The geological map is of considerable interest but the boundary of the Pliocene formation is
inaccurate as it includes considerable Eocene north of San Diego River Valley and probably some
Pleistocene elsewhere.

Marcus A. Hanna’s report”' on the geology of the La Jolla Quadrangle, an area consisting largely
of Eocene strata, contains a short but significant discussion of the Pliocene beds occurring in small
areas in the southern part of that Quadrangle. Hanna mapped the Pliocene-Eocene contact with
considerable accuracy and thus removed much Eocene from the area now known to be occupied by the
San Diego formation, which had been incorrectly placed there by others due to scarcity of fossils and
lack of sufficient field work.

Hertlein”’ in 1929 completed a thesis which was submitted to the Leland Stanford Jr. University,

44 The lower part of the Pliocene as exposed at Elsmere Canyon contains a fossiliferous zone which includes Trophosycon.
This fossil zone is within 100 feet stratigraphically above the Pliocene-Eocene contact. This affords a striking similarity to the
Pliocene beds at San Diego.

45 Aguilera, J. G., Cong. Geol. International, 10th Session, Mexico, 1906, Vol. 10, fasc. 1, pt. 6, p. 244, 1907.

46 Smith, J. P., Journ. Geol., Vol. 18, no. 3, opp. pp. 217 and 226, 1910.

47 Smith, J. P., Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, no. 4, pp. 150-152, 1919, See also, Calif. State Mining Bureau, Bull.
72, table opp. p. 16, p. 38, 1916.

48 Moody, C. L., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 10, no. 4, pp. 39-62, pls. 1, 2, 1916.

49 This correlation was recently discussed by Soper, E, K., and Grant, 1v, U. S., Bull. Geol. Soc. Amer., Vol. 43, pp.
1041-1068, 1932.

50 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, pp. 56-68, 1919
5) Hanna, M. A., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 16, no. 7, pp. 216-218, 1926.

52 Hertlein, L. G., “The Geology and Paleontology of the Pliocene of San Diego, California,” a thesis presented to the
Department of Geology of Leland Stanford Junior University in partial fulfillment of the requirements for the degree of Doctor of
Philosophy, 1929. — Stanford Univ. Bull., 5th Ser., Vol. 4, no. 78, pp. 81-85, July 31, 1929.

VotumE IT} MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 15

entitled “The Geology and Paleontology of the Pliocene of San Diego, California,” and an abstract
of this was published the same year. He concluded that the San Diego Pliocene could be correlated
with the Pliocene of Elsmere, Holser, and Pico Canyons, which he considered to be lower Pliocene
in age. The Pliocene fauna at Cedros Island and Turtle Bay in Lower California was said to be
the closest equivalent to the south.

Grant and Gale, in their memoir on the Pliocene and Pleistocene Mollusca of California, reported
many species from the San Diego formation, and Gale” gave a discussion of the stratigraphy of the
San Diego basin based mostly on field data furnished by Grant. A geologic map”* of California
prepared under the direction of Dr. Olaf P. Jenkins was published in 1938. The geology of the San
Diego region on this map is essentially as it appears in the unpublished thesis of Hertlein. A brief
summary of some of the salient features of the geology of the area included in the present paper, with
numerous well records, was published by the present authors” in a recent number of the California
Journal of Mines and Geology.

A number of papers* not mentioned above contain brief references to the San Diego Pliocene,
but generally they merely restate the conclusions or opinions of others. A few contain descriptions
of new or supposedly new San Diego Pliocene fossils, but these latter will be included in the references
under the particular species in the systematic part of the present work.

The name San Diego formation has been used by Meyerhoff’® for upper Cretaceous beds in the
West Indies. That formational name has had many years prior use in California, and it would appear
to be advisable to rename Meyerhoff’s formation in order to avoid possible confusion.

PHYSIOGRAPHY
GENERAL DESCRIPTION

The area considered in this report can be divided physiographically into two parts, the coastal
mesa region on the west and the mountainous region on the east. These two parts are very distinct,
both in their topography and their geology, the boundary between them being both a topographic and
a geologic unconformity (see physiographic block diagram). Each part has had a somewhat different
history and each is comprised of different rocks. They will be considered separately, although a
complete physiographic picture of the whole area can be obtained only by an understanding of the
genetic connection which exists between them. Some of the features of the coastal mesa region have
been derived from the region to the east, and both, to some extent, have been influenced by the same
forces and geologic processes. The climate, particularly the rainfall, has been of importance in
determining the present relief features of both regions, hence it seems well to present a brief and general
description of the climate at the beginning of this discussion.

CLIMATE AND RAINFALL

The climate of the San Diegan region varies considerably with elevation above sea level and
distance from the coast. Statistics may be obtained from official government weather reports, so that
here it will be necessary only to give such general facts as might have a bearing upon weathering

53 Gale, H. R., in Grant, 1v, U. S., and Gale, H. R., Mem. San Diego Soc. Nat. Hist., Vol. 1, pp. 45-49, 1931.

4 54 State of Calif., Dept. Nat. Resources, Division of Mines. Geologic Map of Calif., prepared by Olaf P. Jenkins.
_ 1, 1938.

> Hertlein, L. G., and Grant, 1v, U. S., “Geology and Oil Possibilities of Southwestern San Diego County,” Calif.
Journ. Mines and Geol., Vol. 35, no. 1, 35th Rept. Calif. State Mineralogist, pp. 57-78, 8 figs. in text, Jan., 1939 [received at library
of the California Academy of Sciences Aug. 23, 1939].

* After the present paper was submitted for publication, a paper by W. P. Woodring, R. B. Stewart, and R. W. Richards
appeared, entitled “Geology of the Kettleman Hills Oil Field, California,’ Prof. Paper 195, U. S. Geol. Survey, 1940 [issued June 7,
1941]. A brief discussion of the fauna of the Pliocene of San Diego is given on pp. 112-113. See also correlation table opp. p. 112.
See also correlation chart by U. S. Grant, 1v, and L. G. Hertlein, State of Calif. Dept. Nat. Resources, Div. Mines, Bull. 118,
preprint of pt. 2, p. 202, Aug. 1941 (issued Sept. 11, 1941); also preprint of pt. 3, pp. 367-369, 1 text fig., March, 1943 (issued
July 1, 1943).

56 Meyerhoff, H. A., Science, New Ser., Vol. 71, no. 1838, p. 323, 1930. Also, New York Acad. Sci., Sci. Sury. Porto
Rico and the Virgin Islands, Vol. 2, pt. 3, pp. 289-290, 1931. The type locality of the San Diego formation is at Punta San Diego,
Porto Rico, Upper Cretaceous.

16 San Dieco Society oF NaturaL History [Memoirs

and the other processes of erosion.” The coastal region has an equable temperate dry climate with
moderate precipitation occurring chiefly between the months of October and April.”* At San Diego the
average annual rainfall is about ten inches. All of the mesa region described in this report is within
this coastal belt of semi-aridity. The higher mountains of central and eastern San Diego County
have a heavier rainfall and a much less equable climate, with a noticeably greater diurnal and seasonal
range of temperature. The coastal belt rarely experiences freezing temperatures in winter nor
oppressively hot days in summer, but the higher mountains to the east frequently receive a few inches
of snowfall during winter, and during summer the temperature, in some of the valleys, occasionally
reaches 100°F. The higher ridges and peaks act as a trap for the eastward drifting rainstorms and a
precipitation of over 40 inches per year occurs on the western slopes of such mountains as the Cuyamacas
and Palomar.”? A rainfall of over twenty inches per year occurs throughout a north-south belt within
the heart of the higher elevations. Lee® has assembled considerable data on precipitation in San Diego
County®' to which the reader is referred for more information than seems justifiable to be included
here.

THE COASTAL MESA REGION

The coastal mesa region extends north and south, parallel and adjacent to the coast line throughout
the San Diego area and continues many miles beyond its northern and southern limit. On the west
this mesa region is truncated by shoreline processes where it extends to the beach, or breaks off more
gradually in a series of marine terraces where separated by bay or coastal plain from the present sea.
The coastal plain is of such limited extent that it is considered a minor subdivision of the mesa
region. In width this region varies from about 6 to 14 miles and in height from over 800 feet (the
summit of Soledad Mountain) to near sea level; but the nearly flat-topped, slightly dissected mesa
that forms the most conspicuous feature has an elevation ranging from about 300 to 550 feet.

The coast line within the area considered here is modified by two promontories, the broad northern

57 The climate has not only directly influenced the more important erosive processes but has determined the type of vegetation.
This has had, in turn, a bearing on the physiographic processes. Lichens, ordinarily such inconspicuous plants, here form an al-
most continuous protective mat over parts of the mesa region, and appear to greatly retard rain wash and sheet-flood erosion, prevent
the rapid development of gullies, and thereby facilitate the accumulation of soil and déeply weathered mantle rock. For example,
on the mesa east of Paradise Valley and north of the Sweetwater River Valley a lichen-moss cover is very prominent. Specimens
collected early in 1938 were submitted to Professor Carl Epling of the Department of Botany, University of California at Los
Angeles, who identified the flora as follows: “The vegetative part of a moss thus far undeterminable; a fern, Selaginella cinerascens;
and two lichens, Parmelia conspera variety stenophylla and Urceolaria scruposa.’’ This vegetative mat holds the surface of the soil
firmly in place, delays sheet-flood run-off, and by lessening the turbidity of run-off, facilitates percolation of rain water into the soil.
A decrease in mud content has been shown to have an important bearing on infiltration of water into the soil. See: Loudermilk,
W. C., “Further studies of factors affecting surficial run-off and erosion,’ Proc. Internat. Congr. Forestry Exper. Stations, 1929,
pp. 606-628, 14 figures. Reviewed by Kirk Bryan in Zeitschrift fiir Geomorphologie, Vol. 6, 1931.

58 From 1908 to 1933 about 95% of the annual rainfall at San Diego occurred between October and April inclusive and
almost 74% between December and March inclusive. (See State of California, Dept. Public Works, Publ. Division of Water
Resources, Bull. 48, table 3, 1935. This paper contains considerable information on rainfall, run-off, and water resources in general
of San Diego County). R. J. Russell, in his studies of climate, using the system of W. Képpen (Grundriss der Klimakunde, Berlin
and Leipzig, 1931) and the Képpen-Geiger Klimakarte der Erde (Gotha, Justus Perthes, 1928), classified the climate in the
San Diego coastal region as BWhn and the foothills as BSh. The BWhn climate is essentially an arid, foggy, coastal desert, and
the BSh its an arid steppe type. (See Russell, R. J., “Dry Climates of the United States. 1. Climatic Map,” Univ. Calif. Publ.
Geography, Vol. 5, no. 1, pp. 1-41, pl. 1, 8 text figs. Jan. 13, 1931. See especially p. 39, and pl. 1). These two climates continue
along the west coast of Lower California, Mexico, with variable width, to below 31° North Latitude. (See Meigs, 3rd, Peveril,
“The Dominican Mission Frontier of Lower California,” Univ. California Publ. Geography, Vol. 7, pp. 1-232, Nov. 30, 1935.
See especially fig. 3 and p, 15). Both these climates occur in Nelson’s Upper Sonoran Life-zone in Lower California. (See Mem.
Nat. Acad. Sci., Vol. 16, Mem. 1, pl. 32, 1922 [separate dated 1921}).

>9Hor Springs Mt., northeast of Warner’s Hot Springs, has the two highest peaks in San Diego County, namely Black Rabbit
Peak, 6,633 feet, and Hot Springs Peak, 6,535 feet, which are separated by a short saddle. The only other point over 6,500 feet high
is Cuyamaca South Peak, 6,527 feet. There are probably a dozen additional peaks in the County with an elevation of 6,000 feet or
more. Some of the better known are Laguna Peak, 6,375; Monument Peak, 6,321; San Ysidro Mt., 6,147; Palomar Mt., 6,138; and
Cuyamaca North Peak, 6,030. (Information received from Mr. B. B. Moore in the office of E. R. Childs, San Diego County
Surveyor; Mr. George Buxton, acting for N. J. Farrell, Forest Supervisor, Cleveland National Forest, United States Department of
Agriculture; and Mr, L. W. Deewall, San Diego County Planning Engineer. February and March, 1943).

60 Lee, C. H., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, pp. 76-99, with several tables and
plates, 1919. See also, Calif. Div. Water Resources Publ., Bull. 48, 1935.

61 Instrumental records of annual precipitation at San Diego began with the season 1850-1851. An interesting study of earlier
rainfall fluctuations in southern California has been published by the Metropolitan Water District of Southern California. See
Lynch, H. B., “Rainfall and Stream Run-off in Southern California since 1769,” Los Angeles, Calif., Aug., 1931.

VotumE II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 17

one formed by the mass of Soledad Mountain near La Jolla, the southern one formed by the isolated
north and south trending Point Loma, and two bays, shallow Mission Bay (formerly called False
Bay) between Soledad Mountain and Point Loma, and the larger and deeper San Diego Bay, which
is protected by Point Loma and a long sand spit called the Silver Strand, Coronado and North
Island. The details of coastline contour can be readily seen on the map (page 50) or on the
physiographic block diagram. The latter also shows the San Diego Mesa and other relief features
in the region.

The eastern boundary of the mesa region is determined by the contact of the overlapping edge
of the Tertiary (Eocene or Pliocene) sediments upon the older crystalline rocks that form the foothills
of the mountainous region to the east. This boundary line becomes somewhat indefinite in detail
where the feather edge of the eastward thinning Tertiaries becomes a mere veneer of soil resting upon

the older rocks beneath.

THE TERRACES
San Diego Mesa

The most conspicuous topographic feature of the coastal portion of the San Diego region is the
broad, relatively flat mesa which occupies most of the area included in the San Diego and La Jolla
Quadrangles. This mesa, here referred to as the San Diego Mesa, is but one of several marine terraces
or plains of marine denudation and deposition, the higher ones, of greater age, being considerably
dissected and less noticeable, the lower ones, developed on the western margin of the mesa, being of
relatively slight area though readily seen where not removed by later erosion.

The San Diego Mesa, the principal terrace, is physiographically a unit, though its separation
by the larger stream valleys has resulted in different names being applied to different parts (see Plate
3). Thus the mesa south of Otay Valley is known as the Otay Mesa and the one north of San Diego
River as the Linda Vista Mesa or Linda Vista Terrace.** Both of these mesas were at one time
continuous before stream erosion began the work of dissection. In the south this mesa has been
elevated higher and apparently more rapidly than in the north, for near the Mexican Boundary
(Otay Mesa) the surface is over 550 feet above sea level, whereas the western portion of the mesa
just south of San Diego River Valley attains an elevation but little over 300 feet; and the greater
vertical interval between the lower terraces in the south indicates a more rapid uplift there.

The surface of the San Diego Mesa, where unmodified by erosion subsequent to emergence and
uplift, slopes gently toward the west except in the southern part, where Otay Mesa has either been
tilted slightly eastward or its eastern surface lowered by erosion more than its western.” This mesa,
when viewed from a point on its surface, appears almost like a featureless plain, the river valleys and
canyons being below the line of vision. However, close inspection reveals some slight irregularities
in detail, such as gentle undulations, long low ridges, some of which are believed to be beach ridges,
and occasional areas of small hillocks or prairie mounds (Plate 6). The gentle undulations may be
due in part to differences in rate of weathering and erosion or to irregularities of uplift, but generally
the exposures of the underlying beds are inadequate to determine the cause. The hillocks, which are
well developed on parts of the Linda Vista Terrace and the mesa west of Sweetwater Reservoir and
the Otay Mesa, often attain a height of 3 or more feet and a basal diameter of 10 to 20 feet. Small
ephemeral pools of water collect between them during spring rains. These prairie mounds or hillocks
are not confined to the tops of the mesa but are sometimes distributed over its gentle marginal slopes
into shallow broad swales which, in some cases, may represent stream valleys of an older cycle than
the present one. It seems likely that their origin is connected with wind action and former vegetation,
possibly the accumulation of aeolian sand around bushes, or irregular deflation between them. The

62 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, pp. 27-28, pl. 7, 1919. This
paper contains an interesting description of the physiography of western San Diego County. See pp. 20-50.

63 We did not observe any eastward dip of the strata underlying the Otay Mesa which could be relied upon as significant.
A one degree eastward dip on the north side of Sweetwater Valley near its mouth is probably local. The eastward slope of the
surface appears to be due to erosion.

18 San Dieco Society oF Naturat History [Memoirs

abundance of these mounds suggests a rather widespread condition different from the present,”
possibly a superabundance of loose sand or finer-grained material exposed to wind transportation soon
after the sea regressed from the present mesa top and while it was actively cutting rapidly widening
benches at slightly lower levels, which are now represented by the terrace 50 feet below the top of
the Otay Terrace and the lower ones mentioned by Ellis. The rather uniform distribution of these
mounds would suggest the even distribution of former vegetation as a controlling factor. An
examination of the soil map of this area” might lead one to suspect that the prairie mounds were
connected in some way with the type and degree of weathering of the soil series on which they are
formed. For example, they are common on strongly or maturely developed secondary soils such as
the Olivenhain series, the Las Flores loamy fine sand and the Redding series, which have been mapped
in the mesa lands of western San Diego County. These soils have an acidic uppermost layer, a clay or
hardpan subsoil, and occur on elevated terraces both north and south of the City of San Diego where
prairie mounds also occur. Such soils promote the growth of widely spaced bushes or clumps of
vegetation and in that indirect way control the spacing of mounds of aeolian material around plants.°°
The fact that lag-gravel does not show notable concentration in the intermound areas may not be
especially significant, as mounds of sand gathered by the wind around clumps of bushes on the
Antelope Valley east of Palmdale have numerous pebbles on them where they were exposed by
burrowing animals now living in holes under the bunches of shrubbery. (See Dalquest and Scheffer,
Journ. Geology, Vol. 50, no. 1, p. 68, Jan.-Feb., 1942).

The beach ridges, described by A. J. Ellis in the paper already referred to (1919, p. 30), are
quite conspicuous in the region north of the San Diego River (well shown on the topographic map
of the La Jolla Quadrangle) where they have controlled the plan of subsequent canyon development,
forcing Tecolote Canyon and smaller canyons east of La Jolla to assume a partial trellis drainage

64 Kirk Bryan has expressed the opinion that the ‘work of the wind is effective only where the rainfall is less than 10 inches
per year (Amer. Journ. Sci., Ser. 5, Vol. 6, p. 306, 1923). The San Diego prairie mounds probably originated during a drier epoch
preceding the Recent epoch.

65 Storie, R. E., and Carpenter, E. J., “Soil Survey of the El Cajon Area, California,’ U. S. Dept. Agric., Ser. 1930, no. 15,
1930. For a soil map of the northwestern part of San Diego County see the pamphlet and map by the same authors in “Soil
Survey of the Oceanside Area, California,” U.S. Dept. Agric., Ser. 1929, no. 11, 1929.

66 A letter dated October 29, 1937, from Professor Chas. F. Shaw, Division of Soil Technology, College of Agriculture,

University of California, Berkeley, contains the following remarks on prairie mounds:

“TI have long been interested in these mounds and have studied them from time to time incidental to studies of other soil
features. It is my opinion that they are in most locations due to the wind drifting of soil and its accumulation around scattered
plants. In the deserts where creosote bush is the dominant vegetative form the plants are usually spaced many feet apart. Each
plant has an accumulation of soil about its base forming a more or less definite mound. This accumulation about the plants
usually goes on until the intervening area has been stripped to the point where a desert pavement has accumulated that retards or
prevents further wind drifting of the soil. The removal of the vegetation usually results in the dissipation of the mounds by further
wind erosion but when such areas are first cleared the location of the mounds is very striking. Such mounds are builded not only
where the drifted material is sand but also where it is as heavy as clay. It appears that this is the probable cause of such mound
formation and I believe that it explains the occurrence of the mounds on most of the soils. On some of the soils, however, there is
evidence that such wide-spaced vegtation may have served to prevent water erosion and the mounds may be remnants of an older
surface. This is the case on some of the soils of the Redding series in the northern part of the state.

“In regions such as the San Diego coastal plain, the deep soils without heavy accumulations of clay in the subsoil or the
presence of hardpan horizons will usually bear a rather complete vegetative cover. Where, however, we have soils with the heavy
clay subsoils comparable to the Olivenhain or Las Flores, or the hardpans of the Redding, the moisture supply is insufficient for a
complete perennial cover and the native vegetation is frequently rather widely-spaced stunted bushes or brush. It is quite probable
that through this effect of soil profile development in rendering the subsoils less pervious and promoting a widely-spaced vegetation,
there may be definite relations between the degree of soil development and the occurrence of the natural mounds. In regions of
still lower rainfall it usually is associated with the competition for moisture.”

Many years ago Dr. G. W. Barnes, first president of the San Diego Society of Natural History, wrote a paper on “The
Hillocks or Mound Formations of San Diego, California” (Amer. Naturalist, Vol. 13, pp. 565-571, 3 figs., 1879). Barnes explained
their formation as due to accumulation of wind-blown material around shrubs or clusters of shrubbery and rain wash of the surface
between. However, some of the spaces between mounds are small enclosed basins which would not permit the escape of rain-washed
material. The present authors believe that rain wash may have modified the mounds but that wind work has been the effective
agent. A brief and still earlier account of prairie mounds occurring on the Pacific slope was given by Joseph LeConte (Proc. Calif.
Acad. Sci., Vol. 5, pp. 219-220, Jan., 1874).

In a Rape: on the mounds of the Columbia Plateau, Waters and Flagler listed thirteen hypotheses to explain the origin of
various types of prairie mounds and stated that, as a physiographic feature, they are polygenetic. See Waters, A. C., and Flagler,
C. W., “Origin of the small mounds on the Columbia River Plateau,” Amer. Journ. Sci., Ser. 5, Vol. 18, no. 105, pp. 209-224,
8 figs. in text, Sepr., 1929.

The results of the work of C. C. Nikiforoff on the microrelief of the “hog wallow” areas of the Central Valley of California
have recently been published by the U. S. Department of Agriculture. See “Hardpan and Microrelief in Certain Soil Complexes
of California,” U. S. Dept. Agric., Tech. Bull. 745, pp. 1-46, 18 figs., April, 1941.

VotumE II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 19

pattern, so different from the almost perfect dendritic drainage pattern of the greater portion of the
mesa. These ridges are generally composed of poorly stratified or unstratified sand of a reddish or
brownish color, the color being due to weathering. The long ridge extending south from Torrey Pines
Park appears to be an ancient beach ridge.” All of these ridges may be due to the accumulation
of beach material just beyond the reach of the waves during a temporary halt of the regressing sea,
or some of them may have been formed in the same manner as offshore bars.*° They are interesting

physiographic details of the San Diego region and are worthy of careful study.

The San Diego Mesa is but youthfully dissected by stream erosion, there being considerable
interfluve area as yet uncut by running water. The northern portion, especially the mesa immediately
adjacent to the south rim of Mission Valley and the Linda Vista Terrace north of it, is less dissected
and hence more youthful than the southern portion, probably due partly to the harder rock in the
Mission Valley region and partly to the closer spacing of the major stream valleys south of Las
Choyas Valley. These valleys were cut by rivers with sources in the mountains far to the east and
have histories which began before the initial stage of subaerial erosion on the relatively recently uplifted
mesa. The Linda Vista Terrace is a fine example of the youthful stage of the normal cycle of stream
erosion. It represents early youth, whereas the southern portions of the San Diego Mesa represent
late youth. Throughout the San Diego Mesa region, with the exception of those portions modified
by the beach ridges already mentioned, the streams have developed a dendritic drainage pattern due either
to the uniform resistance or the horizontal attitude of the sedimentary strata of which the terrain is
composed. Little tributary canyons have cut their way back into the mesa with little choice of
direction, the many side-gullies pointing here and there like the smaller branches and twigs of a tree.
In the eastern part of the mesa-lands some broad shallow valleys and low subdued hills occur which
are strikingly different from the modern steep-sided V-shaped canyons cut by the present intermittent
streams. These can be conveniently seen in the eastern part of the Otay Mesa but they occur elsewhere
to the north. It is on the upper gentle slopes of these old valleys that the prairie mounds already
described occur. While the authors did not have time to study these little subdued swales and valleys
in detail, it seems possible that they were formed while the sea was cutting the terrace next below the
Otay Terrace.® If such is the true explanation, then the short distance these early streams had to
cut down to reach their base level accounts for their having widened their valleys to produce the low
relief features usually associated with old age. In time the modern streams will dissect new V-shaped
valleys within these old ones as headward erosion extends their courses farther and farther into
the mesa.

Many of the canyons and valleys that cut the mesa have relatively steep sides with a sharp-angled
shoulder at the top where valley side and mesa top meet (Plate 4, figure 2). This angular shoulder
occurs where the mesa is capped by a thin but relatively hard and resistant conglomeratic sandstone
discussed on another page as the Sweitzer formation. Wherever this formation occurs on the mesa
it tends to produce steep-walled valleys, with angular shoulders. A peculiar feature of this hard
sandstone layer, connected with its origin, is its unbroken extension from the top of the principal
terrace, the San Diego Mesa, over the intervening slope to the next lower terrace. This can be seen
at but few places (for example, in the Chula Vista region) but it must be considered as having an
important bearing on its origin.

At several places on the mesa the surface layers of soil contain numerous concretionary pebbles
averaging about the size of a pea, though some are a half-inch or more in diameter. These are
brown in color and appear to be due to a concentration of a ferruginous cement. They are less well-

67 This ridge has been partially sectioned by the new Torrey Pines Highway Grade. Another less conspicuous beach ridge
pies Balboa Park from the Natural History Museum north. See the physiographic block diagram for occurrence of these and
other features.

68 The origin and development of offshore bars has been described by D. W. Johnson in “Shore Processes and Shoreline
Development” (John Wiley and Sons), 1919, p. 365 et seq.

69 This terrace is well-developed northeast of San Ysidro (which is 1.6 miles N.W. of Tijuana) at an elevation about 50
to 75 feet below the Otay Terrace. It was included in the Otay Terrace by Ellis (1919, pl. 6).

20 San Dreco Society of Naturat History {[Memorrs

developed beneath the surface and Fairbanks” has noted that they decrease in size to a depth of
about 2 feet below the surface where they cease entirely. These little nodules are quite abundant at
some places, such as on the upper surface of parts of Point Loma and on the Linda Vista Ter-
race, sometimes forming a layer of loose spherules on the surface of the soil. They seem to be
present only where Eocene rocks occur beneath the surface, for the authors failed to note any of them
on the Pliocene mesa south of San Diego River.

The principal terrace, here called the San Diego Mesa, is probably represented by parts of the
upper surface of Point Loma, though faulting has tilted some of the remnants. It is also represented
by a less obvious surface about half-way up the southern and western slopes of Soledad Mountain,
where it has likewise been been tilted by diastrophism.

The surface of San Diego Mesa has been developed almost entirely on Eocene and Pliocene
rocks, the older rocks to the east probably having been too resistant to wave erosion to have been
much reduced during the time the sea was at the proper elevation to truncate the Tertiaries. In the
vicinity of La Mesa it is probable some terrace cutting (marine denudation) has truncated the pre-
Eocene crystalline rocks, but the exposures are not good. Marcus Hanna mentioned remnants of
wave-cut cliffs at the eastern margin of Linda Vista Mesa, but these were not studied by the present
authors.

Younger Terraces

The western margin of the San Diego Mesa and the sides of some of the larger valleys contain
well-preserved remnants of lower, younger terraces. In the San Diego Quadrangle, Ellis’’ has
described and mapped five terraces including the Otay Terrace (= San Diego Mesa) but not including
the coastal flats.’* Beginning with the one next younger and just below the Otay Terrace, there are:
the Avondale Terrace, with an elevation of from about 200 to 250 feet (Plate 5, figure 2); the Chula
Vista Terrace,’* 100 to 130 feet in elevation; the Nestor Terrace, 25 to 100 feet in elevation; and the
Tia Juana Terrace, 20 to 50 feet in elevation. Aside from these named terraces and the Sub-Otay
Terrace included in the Otay Terrace by Ellis, there are still other but smaller, poorly developed and
imperfectly preserved intermediate terraces.. Progressing south from Otay Valley these terraces occur
at higher elevations and are separated by greater vertical intervals. As all the terraces, including the
San Diego Mesa, are remnants of plains of marine denudation (and possibly to a very small extent,
of marine deposition) and hence must each have been formed at approximately the same elevation
during successive still-stands of the sea with respect to the land, it is apparent that uplift has been
greater and more rapid as the Mexican Boundary is approached from the north. As it seems probable
that most if not all of the terraces are probably not younger than middle Pleistocene, they testify to
the lack of orogenic diastrophism in this region during a time when a large part of southern California
north of the San Diegan district was undergoing diastrophism of considerable intensity.

These terraces warrant more intensive field work than the authors were able to devote to them.
Some of them extend a considerable distance up the major river valleys. This latter fact has an inter-
esting bearing on the ages of the valleys, and of course the older terraces in the mountains to the east
also present evidence bearing upon the physiographic history of the region as a whole.

Older Terraces

In the foothills and mountains of crystalline rocks east of the coastal mesa region an older higher

70 Fairbanks, H. W., Calif. State Mining Bureau, llth Ann. Rept. State Mineralogist, p. 98, 1893. Marcus Hanna
likewise notes these concretionary nodules and gives two figures of them. See Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 16, no. 7,
pp. 218-219, pl. 23, figs. 1, 2, 1926.

71 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, pp. 25-28, pl. 6, 1919.

72 Ellis did not recognize the terrace 50 to 75 feet below the Otay Terrace which is quite distinct in the region just northeast
of San Ysidro. This terrace, which we here call the Sub-Otay Terrace, may have a genetic connection with the prairie mounds and
earlier cycle stream valleys briefly discussed in this paper.

73 Marcus Hanna calls the prominent terrace extending from La Jolla south to Pacific Beach at an elevation of from about
25 feet in the south to nearly 200 feet in the north, the La Jolla Terrace, but he believes it probably corresponds to the Chula Vista
Terrace of Ellis. (M. Hanna, 1926, p. 194).

VotumeE II] MariINE PLIOCENE OF SAN D1EGO, CALIFORNIA 21

terrace can be readily seen. This was described by Ellis, and later by M. Hanna, as the Poway Terrace,
due to its conspicuous development on the hilltops south of Poway Valley (in the northeastern part
of La Jolla Quadrangle). The western part of this terrace is better developed in the northeastern
portion of the La Jolla Quadrangle, north of the San Diego River, than it is farther south. East
of the Linda Vista Mesa it can be seen at the tops of the hills, beginning at the west with an
elevation of between 800 and 900 feet but sloping upward toward the east at the rate of about 50
feet per mile, so that elevations of 1,100 to 2,100 feet are attained in the El Cajon Quadrangle 5 to
20 miles to the east. It is probable that this higher older surface should be referred to as an old-land
surface which had reached the old age stage in the cycle of subaerial erosion before the general
post-Pliocene elevation”* of the entire coast. This old-land surface is preserved on parts of the upper
drainage basin of the San Diego River where recently cut canyons with V-shaped cross sections have
only partly dissected the rolling upland.”? This surface probably had many monadnock hills and peaks
and thus was not a true peneplain although some of its present vertical irregularities may have been
caused by later faulting.”° In the paper on the water resources of western San Diego County referred
to above, Ellis included a preliminary map of the County (1919, pl. 3) on which numerous faults
and lines of topographic expression which suggest the presence of faults are delineated. Although the
present authors were prevented by limitations of time from making a careful field study of the
mountainous region, they believe that some faults will eventually be clearly established and that the
northwestward trending fault bounding Warner’s Ranch Valley (San Jose del Valle and Valle de
San Jose land grants) and the Palomar Mountain mass on the southwest is quite definite. The
fault on the southwest margin of this valley has been considered by Sauer to be an extension of the
Elsinore fault which borders the northeastern front of the Santa Ana Mountains farther northwest.”

In parts of the region around Potrero and extending with interruptions far to the east of Campo
and also for an unknown distance south into Lower California, Mexico, there is an old-land surface
which is probably equivalent to the surface developed farther north. Sauer (1929, pp. 222, 248) has
considered this “rude general level of the western flank of the highland, extending far into Lower
California,” a much dissected and warped Eocene marine terrace (p. 248). In arriving at this
conclusion he may have been influenced by the possible genetic connection between the Poway
conglomerate in the La Jolla Quadrangle, now considered to be of upper Eocene age, and the hilltop
gravels which extend in an interrupted belt from near Witch Creek in a southwesterly direction
towards the hills of Poway conglomerate east of Miramar. These hilltop gravels may or may not
be the fluviatile phase of the Poway conglomerate; but if they are, they represent fragments of a
formation which has, through the vagaries of long periods of erosion, escaped complete destruction.
We do not believe they can be used to fix the date of the development of the old-land surface, since
it seems more probable that subaerial erosion during Pliocene times is responsible for that feature of
the topography. We know of no marine Eocene fossils occurring on this old-land surface and are
disinclined to believe a marine transgression of the sea so far to the east occurred during Tertiary
time.

That parts of this old-land surface were exposed to subaerial agents for a considerable period
seems to be corroborated by very deep weathering. Water supply and reservoir site investigations

74 In his paper on “The Post-Pliocene Diastrophism of the Coast of Southern California” (Univ. Calif. Bull. Dept. Geol.,
Vol. 1, no. 4, pp. 115-160, pls. 8, 9, 1893), Lawson first clearly called attention to the importance of Quaternary uplift along this
portion of the Pacific coast.

75 Merrill (Calif. State Mining Bureau, Biennial Rept., 1913-14, p. 8, 1914. Quoted by Ellis.) believed that faulting and
folding was largely responsible for the irregularities of the topography of this upland area.

76 Ellis (in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, p. 48, 1919) called attention to the
plain-like slope of the highland area, and indicated a number of faults.

77 Carl Sauer, in an important and interesting paper on “Land Forms in the Peninsular Range of California as Developed
about Warner’s Hot Springs and Mesa Grande” (Univ. Calif. Publ. Geography, Vol. 3, no. 4, pp. 199-290, pls. 21-41, 5 text figs.,
Dec., 1929), has described the physiography and explained the topographic development of a portion of northeastern San Diego
County. A carefully prepared map is included which explains the author’s interpretation of the kind of land surfaces represented
and also the major faults. Sauer emphasizes the effect of denudation, sensu stricto, in producing concave land slopes, and stream
erosion in producing convex surfaces. His analysis is based upon the somewhat deductive methods of Walther Penck (in that
author’s “Die Morphologische Analyse”), some of whose interpretations of land forms have been challenged by W. M. Davis (see
“Piedmont Benchlands and Primarriimpfe,” Bull. Geol. Soc. Amer., Vol. 43, pp. 399-440, 10 figs., June 30, 1932).

22 San Dreco Society oF NaturaL History {Memorrs

have shown that the granitic rock in some cases is weathered at least partially and is somewhat porous
to a depth of 100 feet.”*

SHORELINE FEATURES

The configuration of the shoreline of southern San Diego County is irregular due to differences
in geologic structure and rock hardness. Wave erosion has etched out the resistant rock masses and
the prograding or constructional work of the shoreline processes has tended to close up the
embayments, resulting in rocky forelands between which are bays and sandy beaches. North of
La Jolla the Tertiary Mesa composed of rocks of almost equal hardness has been evenly truncated
by wave erosion, resulting in a long series of sea cliffs at the foot of which is a narrow beach. The
land seems to be sinking slowly with respect to sea level, which permits the larger waves during storms
to attack the base of the cliffs, oversteepening them and reducing them by landslides and other
processes of cliff destruction. Observations of the lower southern portion of the cliffs at the Scripps
Institution of Oceanography of the University of California, just north of La Jolla, show a rapid
rate of retreat.”? Along this part of the coast the marine cycle of shoreline development has reached
a mature stage. No promontories remain and the coastline is a long gentle curve. About a mile
south of the Scripps Institution the coast line projects out about a mile due to the resistant nature
of the hard Cretaceous sandstones which outcrop there at sea level. Here the waves have sculptured
the rock in a variable manner due partly to differences in induration of the successive beds of
sedimentary rock, but probably more largely due to the jointing and concretionary nature of the
sandstone. Caves, small arches and irregular stacks have been etched out by wave erosion. What
appears to be a recently uplifted wave-cut terrace, a few feet above high tide, may be a small bench
cut by exceptionally high waves during occasional storms. Southward from La Jolla the shoreline
continues irregular for about three miles until Pacific Beach is reached. There the less resistant Eocene
and Pliocene sediments have yielded more readily to wave attack and this feature, probably in
combination with a local structural low, has produced a mature shoreline.

The material eroded from the shore south of La Jolla and more particularly from the embankment
cut into the terrace upon which the community of Pacific Beach has been built, as well as the sediment
brought to the shore by the small intermittent streams draining the western slope of Soledad Mountain,
has been shifted southward by the coastwise currents, assisted by the waves, and deposited almost
completely across the mouth of Mission Bay (formerly known as False Bay, and by the early Spaniards
as Puerto Falso), resulting in a long sand spit with a narrow tidal opening at the south. This is now
known as Mission Beach. Underlying the sandy surface of this sand spit, at about mean sea level,
and below, numerous cobbles occur which have been encountered in test pits dug by the City Engineer
of San Diego.

Mission Bay seems to have had a structural origin. It may be the submerged southern downwarped
part of the Soledad Mountain block. If this is the true explanation, hidden faults probably exist
near its eastern and southern margins. A fault bordering the east shore of Mission Bay is suggested
by the difference in altitude of Eocene beds on opposite sides of Rose Canyon, the presence of a small
spring”’ near the bay shore between Atwood and Morena, 2.55 miles north of the San Diego River
dike on U. S. Highway 101 (Pacific Boulevard),*' and a tilted block of Eocene strata which formerly

78 Professor C. F. Tolman, verbal communication, 1935.

79T. W. Vaughan (Science, New Ser., Vol. 75, no. 1939, p. 250, Feb. 26, 1932) has recorded a 20 foot recession of a
cliff 21 feet high in 12 years, and lesser recessions of higher cliffs.

Lakes discussed details of erosion of the cliffs along the seaside at La Jolla. (Lakes, Arthur, “Geologizing by the Seaside.
Illustrations of Geologic Phenomena related to Mining as shown in the Sea Cliffs and Caves at La Jolla, near San Diego, California,”
Mines and Minerals, Vol. 23, no. 12, pp. 543-545, 6 figs., July, 1903. — “The Sea and Mining. Illustrations Shown at Sea Coast
of Manner of Making and Destruction of Rocks by Action of Shellfish and Erosion,” Mines and Minerals, Vol. 24, no. 1, pp. 12-14,
6 figs., Aug., 1903).

80H. W. Fairbanks mentioned a large tufa deposit on the “southern” shore of False Bay. See 11th Ann. Rept. Calif.
State Mineralogist, p. 97, 1893. A letter from the late Frank Stephens, dated Aug. 27, 1937, states that in his opinion the spring
mentioned by Fairbanks is the one on the east shore of Mission Bay.

51! This spring, which is now a mere seep, is 2,376 feet north along U. S. Highway 101 from a point where joined by Jellert
Street. This is a little north of where Edison Street, if projected, would intersect the highway. Tufaceous material is exposed in
the road embankment for about 100 yards near the spring.

Vo.umeE II] MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 23

existed north of San Diego River north of Old Town.** A possible southern (east-west) fault is
entirely hypothetical but appears to be strongly suggested by the structural relations in this region.
The chief characteristics of Mission Bay at the present time are its very shallow depth of water, and
the large delta of the San Diego River which threatens to encroach farther and farther upon the
remainder of the Bay.** It seems possible that Salicornia sp. and Spartina leiantha Bentham and other
salt and brackish marsh plants may play some part in reducing the area of occasionally submerged
portions of tidal flats in this region. The Spartina, particularly, may be effective in accelerating
deposition since it grows largely below mean high water** and tends by its presence to reduce the
velocity of currents transporting sediment during times of flood or storm. The Salicornia, on the other
hand, grows mostly above mean high water, and is only partly inundated by extreme high tide. It tends
to prevent erosion, however, and gradually adds to the sedimentary layer by the accumulation of a
“peaty” material composed of its dead stalks and roots.

The small intermittent streams which occasionally flow from Tecolote Valley and Rose Canyon
have built small deltas which likewise reduce the volume and area of the bay. Projecting south into
the bay from Pacific Beach is a broad point which is an extension of the La Jolla Terrace. This is
known as Bay Point or Crown Point. Its surface is largely covered with windblown sand which is
now weathered a light yellowish brown. It may have been built in somewhat the same manner
as the Mission Beach sand spit. Below the covering of aeolian sand, Crown Point is composed of
late Pleistocene fossiliferous cross-bedded sands and silts, and is either an ancient sand spit or the
wave-built portion of the La Jolla Terrace (Plate 14). When the sea submerged Crown Point, the
coastal currents must have swept over what is now the low ground between Mission Bay and San
Diego Bay, isolating Point Loma as an island.

All of the low flat land between Old Town and the northeast margin of Point Loma is a delta
deposit of the San Diego River.*’ This river and its distributaries occupied many different positions
on the growing delta. In 1849 it was flowing into San Diego Bay, according to the manuscript map
of Lieutenant Cave J. Couts of the First Dragoons, U. S. Army.*® The San Diego River is also
depicted as flowing into San Diego Bay in the “Official Map of the Pueblo Lands of San Diego”
compiled by Charles H. Poole, U. S. Deputy Surveyor, in 1856, and in the U. S. Coast Survey Map

82 This tilted block had an east-west strike and dips 45° south. This little hill has been completely removed by grading
operations.

83 A relatively short time ago this bay must have had a considerably greater depth of water, for Sebastian Vizcaino referred
to it as a good harbor, and Derby in 1853 (Senate Exec. Doc. 1, 33rd Congress, Ist Session, pt. 3, p. 111, 1853) stated: “Before
1810 the False bay was sufficiently deep to admit of the ingress of vessels of very considerable size; at present it is filled with shoals
and sand bars, and has hardly sufficient water at low tide for an ordinary sail-boat.”

84 According to the investigations of Dr. Ira L. Wiggins of Stanford University, at the Mission Bay Causeway Spartina
ranges from 1.43 feet to 3.92 feet above Mean Lower Low Water in Mission Bay. The lower limit of Salicornia here is 3.64 feet
above Mean Lower Low Water. Mean High Tide in Mission Bay is 3.70 feet above Mean Lower Low Water. The latter datum
in Mission Bay is 1.21 feet above that of La Playa in San Diego Bay. The lower limit of both Distichlis and Frankenia, when
present, is always just above mean high water. According to Dr. Wiggins, these salt marsh plants have a slightly different vertical
range at other localities. For example, at National City on San Diego Bay, where Mean High Water is 5.20 feet above Mean Lower
Low Water at La Playa, Spartina ranges from 3.46 to 5.93 feet, Salicornia has its lower limit at 4.65 feet, Distichlis lives as low as
5.56 feet and Frankenia has a lower limit at 5.66 feet.

85 G. H. Derby, Lieutenant of Topographical Engineers (Senate Exec. Doc. 1, 33rd Congress, Ist Session, pt. 3, 1853,
p. 111) in 1853 made the following statement in regard to this delta plain: “Judging from the topography, it may be supposed that
the False Bay and San Diego harbor were originally one sheet of water, the sandy plain now separating them having been formed
by the deposits of sand from the river; if this was the case, it was before the settlement of this part of the country, as none of the
old Spanish residents remember, or have any tradition of such a thing. I have, however, been told of the existence in San Francisco
of an old Spanish chart on which the bays are thus represented.” See also J. Kearney, pp. 257-262, in same document.

86 Now in possession of Mr. Cave Johnson Couts of the Guajome Rancho, near Oceanside, San Diego County. This map,
dated April 28th and 29th, 1849, is one of several showing the route traversed by Lieutenant Couts’ Command during this period.

See also report of G. H. Derby (Senate Exec. Doc. 1, 33rd Congress, Ist Session, pt. 3, 1853, p. 110) in which he made
the following statement regarding the former positions of the mouth of the San Diego River: “At the time of the first establishment
of the Mission of San Diego, and the ‘Presidio,’ or military post, this plain, and in fact the whole valley for six miles above, was
covered with a dense forest of sycamore, willow, and cotton-wood, with an undergrowth of various kinds of shrubbery, among which
the wild grape was most abundant. At this time the river ran through the most northerly part of the plain, skirting the hills
represented on the plan, and emptied into False bay. This course it continued until 1811, when, by the continued deposit of sand,
its bed was so much elevated that it altered its channel to the southwest, still however emptying into False bay, until 1825, when
a great freshet occurring it overflowed its banks, destroying many gardens and much property, and formed a new channel discharging
into the harbor of San Diego. From the continued accumulation of sand its course has somewhat fluctuated but has never been
essentially altered since that period.”

24 San Dreco Society oF Natura History (Memorrs

of this region dated 1859. A portion of this latter map has been reproduced in our Plate 1. It shows
an older channel of the San Diego River leading into False Bay. The high rate of deposition from
the river threatened to destroy San Diego Bay as a harbor and the Federal Government diverted
San Diego River into False Bay (now called Mission Bay) in 1853 by the construction of a dike.

A levee or embankment of earth was built from a point near Old Town to a point on the opposite
highland on the north end of Point Loma, a distance of about 3,570 feet. This was built under the
direction of Lieutenant George H. Derby,’ U.S. Topographical Engineers. Work began*® on
September 19, 1853, and apparently was completed®? on November 20, 1853. Later on that same
year heavy rains caused the river waters to wash out a part of the levee and the river resumed its
course into San Diego Bay.”° It continued in this course until 1876’ when an adequate earthen
embankment was constructed which has permanently forced the river into False Bay (see Plate 15,
figure 1).

Since the completion of the levee of 1876 a considerable volume of sediment has been added to
the San Diego River delta in Mission Bay. In 1937 the State of California employed a civil engineer,
Norman O. Glover, to resurvey the profiles surveyed in the delta region by Lieutenant John H. Weeden,
U.S. Army Engineers, in 1875. Weeden’s base line was reestablished and his elevations adjusted to
coincidence with the new levels at the summits of two low knolls of Quaternary non-marine reddish
sandstone in the delta flat north of the west end of the present levee. A comparison of these profiles
indicates no significant change in elevation of the flats south of the levee, but north of the levee much
of the surface is now from 2 to 4 feet above that of 1875.” A brief field study of a portion of the
delta of the San Diego River north of the levee has shown that a deposit of light gray medium-grained
sand, containing abundant brown and yellow weathered biotite mica, about 2 to 4 feet thick, overlies
a brown sandy or silty clay. The upper layer of gray sand may represent the material deposited by

87 For an account of Derby’s work in California see “The Topographical Reports of Lieutenant George H. Derby,”
Introduction, by Francis P. Farquhar, Quarterly of the Calif. Hist. Soc., Vol. 11, no. 2, pp. 99-102, June, 1932. Reprints of Derby’s
reports occur in no. 2, pp. 102-123, 2 maps, June, 1932; no. 3, pp. 247-265, 1 map, Sept., 1932; no. 4, pp. 365-382, 1 map, 6
sketches, Dec., 1932. The separates containing these reports issued by the Calif. Hist. Soc., Spec. Publ. 6, 1933, contain additional
information not included in the complete volume. See especially pp. 65-71 for information regarding Derby’s work at San Diego.

88 See The San Diego Herald, Vol. 3, no. 33, p. 3, col. 5, Sept. 24, 1853. “This work was commenced by Lieut. Derby,
U. S. Corps of Topographical Engineers on Monday last [Sept. 19, 1853]. His orders are to excavate the former channel of the
river discharging into False Bay and to build a levee or embankment of earth from a point near the Old Town to a point on the
opposite high land (distance 1,190 yards) intersected by the Playa road to counteract the action of subsequent freshets. Sixty laborers
with carts, wheelbarrows, etc., are to be put on the work at once”...

89 Letter from Lieut. George H. Derby to Col. J. J. Abert, Chief Topgl. Engineers, San Diego, Nov. 20, 1853. “I have
the honor to inform you that the work on the San Diego River was this day completed, in the manner described in my report of
the 15th Oct. ult.” (Letter on file in the archives of the U. S. Army Engineers, War Department, Washington, D. C.).

90 See the San Diego Herald, Vol. 5, no. 1, p. 2, col. 4, April 21, 1855. “We mentioned some time ago that a part of the
dam which Lt. Derby, U. S. Top. Eng., erected, for the improvement of San Diego harbor had given away under the pressure of
water caused by the first heavy rains, and that the river, which had been turned into False Bay, was running in its original channel.
In four years we have never known the water to be so high as this season. The rain which fell during the early part of the week has
had the effect to considerably widen the breach in the dam and if something is not done before the next rainy season to repair the
damage the amount of the outlay which has already been made, will be worse than thrown away.”

91 On June 5, 1876, ground was broken for the new levee which was completed on Nov. 6 of the same year. Ann. Rept. Chief
of Engineers [U. S. Army] for 1876, pt. 1 (44th Congress, 2nd Session, House of Representatives Ex. Doc. 1, Vol. 2. pt. 2,
1876), p. 114; Ann. Rept. Chief of Engineers for 1877, pt. 2 (45th Congress, 2nd Session, House of Representatives Ex. Doc. 1,
Vol. 2, pt. 2, 1877), Ap. II, p. 998.

Additional information regarding the dike can be found in the Ann. Rept. Chief of Engineers for 1874, pt. 1, p. 119, pt. 2, Ap.
AA3, pp. 372-375; 1875, pt. 2, Ap. FF2, pp. 723-724; 1878, pt. 1, p. 136, pt. 2, Ap. II1, pp. 1301-1302. According to accounts
the north side of the levee was faced with a heavy stone wall which rested on a stone foundation five feet deep. The levee was over
7,000 feet long, 15 feet wide at the top, 40 feet wide at the base, and 5 feet high. See also the San Diego Union, Sept. 11, 1876.

The earth used in the construction of the dike came in part from the cliff at the northeastern end of Point Loma near the
Present intersection of Mission Bay Causeway and West Point Loma Boulevard and in part from the site of the fort on the point
of the hill below the old Presidio at Old Town. According to a local historian: “Nothing whatever of the site [of the old fort]
now remains, the earth forming the point of the hill having been hauled away and used by the government engineers in making
the embankment for turning the San Diego river, in 1877. Some of this earth was also used for grading the county road across the
valley from the end of the Old Town bridge, in later years. These excavations also took large quantities of earth from the north side
of the hill, the extent being measured by the widening of the road from a narrow track to its present width.” (See Black, Samuel F.,
“San Diego County, California. A Record of Settlement, Organization, Progress and Achievement,” The S. J. Clarke Publishing
Co., Chicago, p. 82, 1913).

92 See testimony, and plaintiff's exhibits Nos. 3 and 9, People of the State of California vs. Charles E. Arnold et al. No.
84864 Superior Court San Diego County, Hon. Chas. C. Haines, Judge, 1938.

VotumeE II] MarINE PLIOCENE OF SAN DrgEGO, CALIFORNIA 25

the San Diego River during the flood discharges since 1875. At one locality this sand contained a
specimen of Physa, a fresh water shell, and at another, a piece of broken Indian pottery.

Like most streams in this region the San Diego River is characterized by infrequent floods”
during which a large amount of sediment is carried to its delta. These occasional floods have been
the effective agent in building the delta because the river is generally dry during late summer and
autumn and may be dry for an entire year or more. The construction of the El Capitan Dam** on
the San Diego River about seven miles above Lakeside in 1935 may reduce the frequency and violence
of future floods and delay the growth of the delta in Mission Bay from now on.

In addition to the growth of the delta of the San Diego River in Mission Bay, some shoals and
small islands have been formed in that shallow body of water by the action of tidal currents and waves.
The light areas shown on Plate 17 at the western extremity of the deltaic region (extreme right middle
part of view) are small dune ridges, two of which reach an elevation of about 10 feet above Mean
Lower Low Water. The sweep of the currents in and out of the narrow entrance channel of Mission
Bay tends to deposit a submarine bar off the ocean end of the entrance and tidal inlet delta shoals
within. Wherever the incoming currents spread over a greater cross-sectional area their velocity diminishes
and consequently their power to transport sediment decreases. The first rapid decrease in velocity occurs
just within the entrance to the bay and there a prominent shoal occurs which is exposed at low tide. It is
an incipient tidal inlet delta island which has nearly reached the plane of Mean High Water. As the
incoming currents flow northward east of the Mission Beach spit they fan out over a larger area and
deposit some of their load of sediment across the bay floor west of the causeway and southwest of the
south end of Crown Point. The shoaling here has been sufficient to permit a luxuriant growth of
Spartina. Some of the Spartina-covered shoal areas are shown to the right of Crown Point on Plate 17.
Other Spartina-covered shoals east of the causeway seem to indicate further spreading out of the currents.
The reduction of the tidal prism in Mission Bay has undoubtedly slowed up this island-forming process.
At a previous time, when the river delta was smaller and the volume of tidal water was larger, the
currents were more effective and tidal current island formation took place on a larger scale. It seems
highly probable that a portion of the deltaic area west of the causeway was originally formed as a tidal
inlet delta island. Field studies by Grant and the mechanical analysis of sediment samples tend to
confirm this theory. The formation of such islands has been recently described by Lucke.”

Point Loma is a long promontory extending from the tidal flats of Mission Bay for a distance
of over six miles to the south. It land-locks the western portion of San Diego Bay. Its northern part
is nearly three miles wide but it narrows toward the south to a little over one-half mile near the extreme
point. Its truncated top averages just over 300 feet in elevation except in the northern broader part which
is somewhat lower. The terraced top may have originated at the same time as the San Diego Mesa,
and its isolation may be due to relatively recent (possibly late Pleistocene) foundering of the formerly
continuous land on one or more sides.*® Parts of its eastern and western shoreline are bordered by a
narrow terrace with an elevation up to 25 or more feet. Stephens considered this terrace as well as the
La Jolla Terrace (the Nestor Terrace of Ellis) the result of a submergence following the great Pleis-
tocene emergence. Point Loma does not exhibit the well-defined intermediate terraces which characterize
the western margin of parts of the San Diego Mesa. The western shoreline of Point Loma is irregular

93 According to Mr. H. B. Lynch, consulting hydraulic engineer of Los Angeles, floods occurred in the San Diego River in
the following years: 1811; 1825 (San Diego River broke into San Diego Bay); 1839-40; 1855; 1857; 1862; 1873-74; February,
1884; December, 1889; January, 1916; February, 1927.

Mr. Fred D. Pyle, Hydraulic engineer for the City of San Diego, states in a letter dated November 24, 1939:

“Two years ago in studying the preliminary flood control problems of the San Diego River, the Army Engineers reported floods of
maximum intensity in the following order: 1862, 1916, 1825, 1927. The 1883-84 season produced by far the most water of any
year of historical times but did not produce maximum intensity of floods comparable to those mentioned above.”

Early floods in the San Diego River are mentioned by several historians. See Gunn, Douglas, “Picturesque San Diego, with
Historical and Descriptive Notes” (Knight and Leonard Co., Chicago), 1887, p. 25.

94 This dam, which began to impound water Jan. 8, 1935, has a capacity of 38,000,000 gallons.

95 Lucke, J. B., “A Study of Barnegat Inlet, New Jersey, and Related Shoreline Phenomena,” Shore and Beach, Vol. 2,
no. 2, pp. 5-54, 1934. — “A Theory of Evolution of Lagoon Deposits on Shorelines of Emergence,” Journ. Geol., Vol. 42, no. 6,
pp- 561-584, 11 text figs., Aug.-Sept., 1934.

_ 96 Fairbanks mentions a “strong sulphur spring exposed at low tide” at the end of Point Loma. We did not locate this spring
during our field work. It may have some bearing on faulting. See 11th Ann. Rept. Calif. State Mineralogist, p. 97, 1893.

26 San Dieco Soctety oF Natura. History [Memorrs

in detail due to the hard Cretaceous rocks exposed at sea level.

San Diego Bay is an elongate, irregular crescentic, land-locked body of water connected with the
ocean by a narrow tidal channel on the east side of Point Loma. The entire southern and southwestern
shore of the bay consists of North Island and Coronado Island and the sand spit which connects them
with each other and both of them to the mainland at the south. North Island and Coronado Island
may be remnants of the Nestor Terrace, as supposed by Ellis,”” but their connection to the mainland is
due to a long crescentic sand spit which appears to have been constructed by the northward shifting
of material brought to the shore by the Tia Juana River which reaches the sea near the Mexican
Boundary. Spanish Bight is a small, shallow re-entrant of San Diego Bay between North Island
and Coronado.”

Except where occasional dredging has maintained a deep-water navigable channel, San Diego
Bay is relatively shallow. Tidal scour at the entrance has been assisted by a jetty. This jetty, known
as the Zuninga or San Diego Jetty, may have had some important effect upon the currents and wave
action along the ocean shore of Coronado and North Island. Shortly after it was built, large waves
during a storm in the spring of 1905 eroded away a large part of Ocean Boulevard west of Hotel del
Coronado. In regard to the construction of this jetty, Lieut. Col. R. A. Wheeler, Corps of Engineers,
U.S. Army, states in a letter to us dated Washington, D. C., July 29, 1938: “The river and harbor
act approved September 19, 1890, authorized the construction of a jetty 7,500 feet long on Zuninga
Shoal with a view to securing a depth of 26 feet on the outer bar. The jetty, of rubble stone construction,
was built to the height of extreme high water and was completed in 1904. The annual report of the
Chief of Engineers for 1937 states that the jetty has deteriorated to the extent of about 75,000 tons
of stone displaced.” According to a report by Colonel Chas. T. Leeds to Mr. M. W. Reed, City
Manager of the City of Coronado, the Zuninga Jetty was begun in October, 1893, and its construction
continued intermittently until its completion in July, 1904. In a report by Mr. D. E. Hughes, Assis-
tant Engineer, to Lieut. C. T. Leeds, dated April 26, 1910, it is stated that following the extension
of the Zuninga Jetty in 1900, erosion occurred just west of Spanish Bight, so that the railroad tracks
supplying material to build Battery Meed (just northwest of the root of the jetty) had to be moved
in 1901. Erosion began again during the next extension of the jetty in 1903 to 1904, this time farther
east along Spanish Bight and eastward. ;

A small stone jetty or breakwater was built just southeast of the Hotel del Coronado in 1897
and 1898 to protect the hotel from wave erosion. It was repaired and extended at a later date.”
Although the prevailing direction of drifting of beach material along the Silver Strand southeast of
the hotel property appears to be toward the northwest,'°° the beach adjacent to the hotel property
came under the influence of the Zuninga Jetty when it was extended to its full length. According to
a report dated January 8, 1909, by Mr. Andrew Ervast, then Engineer of the Coronado Beach Com-

97 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, pl. 6, 1919.
98 Neither of these is now a true island because they form a part of the Coronado peninsula.

99 Data from report by Col. Chas. T. Leeds to Mr. M. W. Reed, City Manager of Coronado. In addition to this break-
water, “About 1900 there was constructed, a short distance east of the ‘hotel breakwater,’ and close to the bath house, a small
rock groin.” By 1931 the rocks of this structure were almost completely buried in beach sand. (From rept. of Col. C. T. Leeds).
In Sept., 1940, some of these rocks barely protruded above the sand.

100 Foreshore beach samples collected on Aug. 23 and 24, 1940, from the Zuninga Jetty to the Mexican Boundary showed,
in general, a gradual increase in median grain size of sand particles from North Island to the mouth of the Tia Juana River. The
partly decomposed golden-brown biotite flakes so abundant on the foreshore of North Island and Coronado Beach are much less
common further southeast. The foreshore slope of the beach is also much steeper in the south than on North Island or Coronado
Beach. The slope of the foreshore appears to be at least in part a function of grain size, and the latter is controlled by the violence
of wave action. Back of the beach on North Island and back of the beach along the Silver Strand and southward to the Mexican
Boundary there are small sand dunes which testify to the action of on-shore winds in removing sand from the beach. No notable
accumulation of pebbles or cobbles was seen in this sand dune area except south of the mouth of the Tia Juana River, where a large
number of flattish pebbles 1 to 4 inches long lie mostly buried in the sand of the eastern part of the small dunes, (see Plate 5,
figure 1). Dr. Cordell Durrell, who examined these pebbles for us, determined them as dominantly hard metamorphosed andesitic
and rhyolitic porphyries with occasional specimens of lime silicate hornfels. They are probably of pre-Cretaceous origin. They
probably represent a local accumulation of material eroded from the bluffs of the Pliocene rocks back of the beach just south of
the International Boundary. That they do not represent a concentration of gravel from the Tia Juana Valley alluvium is apparent
from the fact that specimens of hornblende-rich andesite, basalt, and other non-metamorphics are absent in the beach deposits, but
are common in gravel lenses in the valley fill encountered in well cores a mile or two east of the beach. The pebbles in the valley
fill are, in general, less well rounded than those near the beach.

VotumE IT] Marine PLIOCENE OF SAN DIEGO, CALIFORNIA 27

pany and City Engineer of Coronado, local news items in the San Diego Union,’ and data assembled
by Col. Chas. T. Leeds, storms in January, 1905, (during flood tide on about the 4th and 20th of
the month), on February 5th, 1905, and again during the middle of March, 1905, caused serious wave
erosion along the Hotel del Coronado grounds and Ocean Boulevard just west thereof. Mr. Ervast’s
report mentions that along Ocean Boulevard a total width of 110 feet of land was removed by the
waves, leaving a vertical bank 6 to 18 feet high. To prevent further erosion such as was caused by
these storms, a seawall of quarry-run stone 5,200 feet long was built from the hotel westward along
Ocean Boulevard between August, 1906, and October, 1907. It was repaired in 1912 and 1928.

The mainland shore of San Diego Bay is mostly salt marshes and tidal flats, except where the
presence of the Nestor Terrace produces a small bluff just above high tide line. The small inter-
mittent streams from Las Choyas, Sweetwater and Otay Valleys have constructed small marshy deltas.

Tia Juana’ River, which flows into the ocean south of San Diego Bay, has not produced a delta
because the waves and currents have been effective in removing the sediment as fast as it is brought
within their reach.' However, the river-transported silt has caused a gentle projection of the coast,
but present day sinking of the land has resulted in salt marshes and small tidal lagoons behind the
spit-like sandy beaches which are witnesses of the greater strength of the waves and long-shore currents.
The northward shift of the sediments is due to either an eddy on the lee or southeast side of Point
Loma or to the occasional southwest storm winds whose effect, though of short duration, is greater
than the prevailing but gentle west and northwest breezes.

The Nestor Terrace is continuous from the foot of the San Diego Mesa (called Otay Mesa on
the topographic map) westward to the beach north of the mouth of the Tia Juana River, except for
a little swale extending from the Tia Juana Valley northwesterly to the southern end of San Diego
Bay. This small drainage depression crosses the road just west of Nestor and Palm City. It appears to
represent a channel eroded by occasional overflow waters from former great floods in the Tia Juana
Valley, but it does not indicate a former course of the Tia Juana River into San Diego Bay. The Otay
River and the Sweetwater River, which enter the bay, may have had some part in eroding a valley
which is now submerged and represented by the southern part of San Diego Bay.

THE PENINSULAR MOUNTAINS

The mountains of San Diego County appear, in general, to be a series of irregularly disposed
peaks and ridges transected by numerous stream valleys. If one could imagine all the valleys filled
up to their margins, then one would see an old-land surface bearing numerous projecting hills and
peaks but all with a gradual ascent from the foothills on the west to the highest summits on the east.
This hypothetical picture, however, would not be an ideal example of the old age stage in the normal
cycle of stream erosion, for faulting has entered the scene and broken up the terrain so that some blocks
have been elevated more than others. Thus the general elevation is not uniform throughout a
gradually eastward ascending surface. The Palomar Mountain mass, Volcan Mountain, the Laguna
Mountains, and others, appear to have derived their topographic prominence at least partly by faults.
These faults are in most cases hard to locate in this region of crystalline rocks except by their topo-
graphic expression or zones of brecciation. It appears that the supposed presence of some faults which

101 See, for example, San Diego Union, Feb. 4, 1905, pp. 1, 3; Feb. 5, 1905, p. 5; Feb. 7, 1905, p. 6.

102 Tt should be mentioned that the spelling “Tia Juana” is that of American usage as shown on the topographic map of
the San Diego Quadrangle, whereas the official Mexican spelling is “Tijuana.”

103 The discharge of sediment by the Tia Juana River will no doubt be decreased in the future, due to the construction of
the Rodriquez Dam on this river about 11 miles (17 kilometers) east of the municipality of Tijuana. This dam, which has a
capacity of 137,000,000 cubic meters and was completed in February, 1937, was constructed for the storage and diversion of water
for irrigating about 5,000 acres in Tijuana Valley in Mexico and for domestic use of the 10,000 inhabitants of Tijuana. See
Williams, C. P., “Foundation Treatment at Rodriquez Dam,” Proc. Amer. Soc. Civil Eng., Vol. 58, no. 8, pp. 1375-1385, Oct.,
1932 — Trans. Amer. Soc. Civil Eng., Vol. 99, paper no. 1863, (Proc. Vol. 60, no. 8, pt. 2) pp. 295-313, 9 figs., 1934. The total
drainage area of the Tia Juana River is about 1,668 square miles, of which 939 square miles are above Rodriquez Dam. Since there
are about 250 square miles of drainage above Barrett Dam on Cottonwood Creek, a tributary in the United States, the lower Tia
Juana River now has a total of only 479 square miles of uncontrolled drainage area below the dams. See 71st Congress, 2nd Session,
House Doc. 359, “Report of American Section of International Water Commission, United States and Mexico,” April 21, 1930,
Ap. 1, p. 79, and map facing p. 84.

28 San Disco Socrety oF Naturat History [Memorrs

have been reported in this region is based upon slight evidence. The trend of most of the important
faults is roughly northwest and southeast, thus partaking of the general directional pattern of well-
known faults farther north, such as the Elsinore fault, the San Jacinto fault, and others.

It can hardly be said yet with absolute certainty from our limited knowledge of this country
that the gently rolling surface on the higher parts of the Palomar Mountains, the upland meadows and
subdued hills on the summit area of the Laguna Mountains, and other similar features, are upfaulted
correlatives of the less elevated but more extensive general old-land surface of the region as a whole.
The existence of these subdued topographic forms so far from the coast, so high in elevation and not
yet maturely dissected by the narrow, deep canyoned streams which are actively eroding their courses,
suggests a recent rejuvenation of the entire region with the initiation of a new erosion cycle which
has now reached only the stage of late youth.

This mountainous area is terminated on the east by a steep descent to the low depressed area of
the Colorado Desert. It seems highly probable that this eastern margin of the Peninsular Range is
defined by faults, but the irregular margin of the mountains, with numerous projecting ridges extending
far eastward into the desert, suggests a complex series of faults rather than one fault or one fault zone,
which would tend to produce a scarp of a more nearly linear character.

STREAM VALLEYS AND DRAINAGE
Coastal Mesa Region

The larger valleys which have been cut through the San Diego Mesa, such as Mission Valley,
Sweetwater Valley, Otay Valley and Tia Juana Valley, are characterized by flat sandy or silty bottoms
and abrupt side slopes, the river channels being three hundred feet or more below the upper surface of
the mesa. All these major valleys have been eroded into the relatively soft Tertiary sediments of the
mesa by rivers whose headwaters are far to the east in the mountainous region where the annual rainfall
is much greater than that of the coastal area. Otay Valley, unlike the others mentioned, has a broadly
rounded bottom which may be due to its being a younger valley, as explained by Ellis. All these valleys
owe their flat floors to aggradation, the valley fill being possibly as much as two hundred feet deep
in some cases.'°* The depth of the river alluvium in the Tia Juana Valley has been determined by
a geophysical survey made in connection with underground water problems. About 3,200 feet north
of Monument School (which is just east of the mouth of Smallcomb’s or Smugglers’ Canyon) the
bottom of the valley fill is at approximately 110 feet below mean sea level. As the surface there is just
over 20 feet above mean sea level, the vatley fill is over 130 feet thick. Along a north-south geophysical
traverse about 6,200 feet west of the Monument School the maximum depth of the bottom of the
valley fill is at approximately 120 feet below mean sea level. This is about 500 feet north of the location
of the Holderness Well mentioned in another part of this paper. It is of interest to note here that
the ground water table in the Tia Juana Valley (except within the temporary depression cones sur-
rounding actively pumping wells) is sufficiently above sea level to prohibit the influx of sea water
beneath the fresh water under the principle of Ghyben and Herzberg.'””

During the time of greatest emergence in the Pleistocene the major streams cut deeply into the
Tertiary strata but have since aggraded their lower courses. The minor valleys and the tributaries
of the larger ones just mentioned are characterized by steep-sided V-shaped cross-sections. Except
where the ancient beach ridges north of Mission Valley have controlled the initial post-emergent run-off

104 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, p. 33, 1919.

105 Badon Ghyben, W., “Nota in verband met de Voorgenomen Put boring Nabij Amsterdam,” Tijdschr. Kon. Inst. Ing.,
1888-89, p. 21, The Hague, 1889; Herzberg, Baurat, “Die Wasserversorgung einiger Nordseebader,” Jour. Gasbeleuchtung und
Wasserversorgung, Jahrg. 44, Munich, 1901. Well explained by John S. Brown, “A study of coastal ground water,” U. S. Geol.
Surv., Water Supply Paper 537, pp. 16-18, 1925. See also, Tolman, C. F., “Ground Water,” (McGraw-Hill Book Co., New York,
1937), pp. 246-247; Stearns, H. T., and Vaksvik, K. N., “Geology and Ground-Water Resources of the Island of Oahu, Hawaii,”
Territory of Hawaii, Dept. Public Lands, Division of Hydrography, Bull. 1, pp. 237-238, May, 1935.

The Ghyben-Herzberg principle is strictly true only in cases of hydrostatic equilibrium, that is, when the fresh water is at a
constant potential. For low potential gradients the formula expressed in the Ghyben-Herzberg theory is approximately correct,
but where ground water near a pumping well or near the sea has considerable motion the dynamic equations developed by Professor
M. King Hubbert should be used. In the latter case the fresh water-sea water contact under the land surface is lower than the value
given by the static equilibrium formula. See Hubbert, M. King, “The Theory of Ground-Water Motion,” Journ. Geol., Vol. 48,
no. 8, part 1, Nov.-Dec., 1940, especially pp. 870-873, 924-926.

VoLuME II] MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 29

and thus deflected the streams, the drainage pattern is distinctly dendritic. The steep valley sides, often
with little talus accumulation at the base, are more or less characteristic of regions of small annual rain-
fall, with occasional sporadic floods.

Peninsular Mountains

East of the San Diego Mesa the streams have cut steep-walled valleys into the crystalline rocks
of the mountainous region which characterizes the central and eastern parts of San Diego County.
The San Diego River and Sweetwater River flow for many miles through deep, steep-sided valleys,
with the river beds often 500 or more feet below the old-land surface described on a preceding page.
This is well shown in the view of a canyon, cut by a tributary of the San Diego River, illustrated in
Plate 4, figure 1. These valleys give the appearance of being entrenched through a recent revival of
erosion. San Diego River, the largest river in southern San Diego County, has a flat floor or flood
plain for some miles above Lakeside, but the steep valley sides with the more or less angular shoulder
at the rim of the old-land surface, and the V-shaped tributary valleys, are characteristics of youth in
the present cycle of erosion. Occasional broad valleys exist in parts of the drainage basins of these
rivers, such as Potrero Valley, Morena Valley, Pine Valley, Descanso Valley, and others. They are
probably due to variation in rock resistance or to structural causes not determined by us. Some of the
upper tributaries of San Diego and Sweetwater Rivers have their sources in swampy or damp near-
summit meadows.

The drainage of the mountains is nearly all westward, the divide between streams flowing to the
Pacific and those flowing to the desert being very close to the eastern margin of the mountains. The
drainage pattern is very irregular, which appears to be due to structural causes, in some instances
possibly due to faulting; but this problem requires much study. Ellis has indicated the probable ex-
istence of a number of faults which have influenced the drainage, and Sauer has described some valleys
in the Mesa Grande region which are probably genetically connected with faults.

PHYSIOGRAPHIC HISTORY

An adequate treatment of the geomorphogeny of that portion of San Diego which is briefly
described, for the most part in an empirical manner, in the present paper, would require a long and
intensive field study which the present authors have not been able to pursue. It is hoped that the brief
outline of a probable series of more important events given here will be taken as a stimulus to an
intensive study by others and not as a final interpretation or explanation of this very interesting and
physiographically complex region. Gale'°® has presented some ideas on the origin of the San Diego
Mesa, based largely on field data furnished by Grant.

The San Diego Mesa, composed of gently inclined Eocene and Pliocene sediments, is a plain of
marine denudation, the Tertiary strata being distinctly truncated. During the deposition of the Pliocene
sediments the sea must have had a position far above the present mesa surface, possibly an elevation
of 800 feet or more above present sea level, or 300 or 400 feet above the present mesa level. Thus the
San Diego formation of Pliocene age must have once extended far north of Mission Valley and possibly
considerably east of its present limits. It is possible that a long still-stand of the sea during approxi-
mately middle Pliocene time represents the period when the Poway Terrace was developed by subaerial
erosion; and possibly the old-land surfaces farther east can be correlated with it. If this explanation
is correct, then the fine grain size of the silts and sands of the San Diego formation (containing rela-
tively little gravel and cobbles) is explained by the subdued topography from which the somewhat
sluggish Pliocene rivers derived their clastic loads. This mid-Pliocene time of low relief on the land
(and high stand of the sea) appears to be represented in mountains east of the mesa lands by the
subdued relief and old-land features described above.

Sometime after this approximately middle Pliocene period of submergence during which the San
Diego formation was laid down, there began a slow uplift and tilting westward of the entire region

( hig Gale, H. R., in Grant, 1v, U. S., and Gale, H. R., Mem. San Diego Soc. Nat. Hist., Vol. 1, pp. 45-49, diagram C
p- LOSI.

30 San Dieco Society of Naturat History [Memoirs

back as far as the escarpment on the east side of the present Peninsular Range in southern San Diego
County. The early phases of the faulting which have left an impress on the present physiography of
the mountainous region may have begun at this period. Possibly these newly inaugurated faults resulted
in the formation of enclosed or partly enclosed basins within which some of the continental sediments
were deposited by the revived streams.’ The effect on the San Diego Mesa of this gradual uplift
and tilt toward the west was to truncate and lower the surface of the recently deposited Pliocene sedi-
ments by wave scour at the profile of equilibrium. Also, the revived streams on the land to the east
began bringing to the sea coarse material which was shifted alongshore and over the sea floor by
the waves. The increased erosive power of the streams, alone, might account for the bringing to the
sea of the gravel and cobbles which were later to be left on the truncated mesa as the Sweitzer forma-
tion, or faulting might have added heavy material to stream loads where fault scarps or shattered
zones were athwart stream channels. The effect of this gradual uplift and westward tilt on the area
east of the coast was to rejuvenate the region and inaugurate a new cycle of erosion. This new cycle
was impressed upon the previous cycle which had not yet reached the peneplain stage but had probably
attained early old age. During this period the Sweitzer formation, which lies nonconformably on the
truncated mesa deposits, was formed as a stream supplied, but probably wave and current shifted,
residual veneer on the shallowing sea floor.

This uplift and tilting continued, but probably at varying rates and with occasional periods of
quiescence. During a time of rapid elevation the sea was unable to maintain its position over the
submarine terrace of Pliocene sediments,'°* but was forced to retreat to the outer edge of the deposit
where it began to cut a new terrace in them at a lower level. During the retreat of the sea off the mesa,
it left behind beach ridges which still remain on the Linda Vista Mesa north of Mission Valley.
At about this time or a little later it is probable that many of the prairie mounds were formed on the
mesa by wind transportation of super-abundant loose clastic material not protected by an adequate
cover of vegetation. Successive lower positions of the sea during the intermittent uplift resulted in
the series of minor terraces which are still partly preserved on the outer marginal slope of the San Diego
Mesa. The development of each lower terrace tended to areally reduce the next one above and it thus
follows that the San Diego Mesa as a whole, and each lower terrace, may now be but a remnant of
its former extent. Thus the continued but intermittent elevation of the land, possibly accompanied
by a continuation of the westward tilt of the entire eastern orogenic block, resulted in the emergence
of the San Diego Mesa and the cutting of a series of lower terraces on its seaward margin. The rivers
on the land area to the east continued to be revived and were thus able to entrench themselves in steep-
walled canyons below the general level of the old-land surface inherited from the previous (incomplete)
erosion cycle. As soon as the San Diego Mesa emerged above the sea the larger streams, already well
established in their valleys to the east, cut steep valleys through the relatively soft Tertiary sediments
in their courses to the new more western shoreline of the sea.

The presence of what have been interpreted as submarine valleys off the coast of southern Cali-
fornia, the great thickness of alluvium filling the bottoms of the major valleys in the San Diego Mesa,
and the very incomplete known marine Pleistocene fossil record in San Diego County, all suggest
an emergence of the coastal region to an elevation considerably above its present position during post-
San Diego time. It was during this great emergence of the land that the larger rivers cut their beds
so far below the present valley bottoms in the mesa region. Due to the much more resistant nature of
the crystalline rocks east of the Tertiary sediments, none of the rivers were able to cut their channels
below their present levels except in limited parts of their courses where local warping or the crushed
nature of the rock near faults favored rapid erosion. Thus San Diego River and Sweetwater River
at present flow over alluvial-filled valley floors in only limited parts of their courses in the foothills of
crystalline rocks. It is possible that this great emergence occurred at the same time as the mid-Pleistocene

107 Reed, R. D., “Geology of California,” p. 22, footnote 2, 1933, Reed states: “Vertebrate fossils of probable upper
Pliocene age have recently been found in extensive sedimentary deposits a few miles west of Warner’s Hot Springs.”

108 The truncation of the mesa was sufficient to remove all of the Pliocene sediments north of the San Diego River, and
also an unknown thickness of the Eocene below. Of course, it is possible that the mesa was truncated by wave erosion entirely on a
landward retreating sea cliff which began as a notch on the outer edge of the emerged terrace.

VotumeE II] MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 31

orogenic disturbance (termed the Pasadenan Orogeny by Hans Stille) that folded and faulted so
much of the Tertiary and lower Pleistocene strata in the Los Angeles-Ventura region, but there are no
direct means of testing this possibility at the present time. The faults in the Peninsular Range of San
Diego County may have been active at this time.

As stated by Stephens and others, the period of uplift appears to have been followed by a later
submergence of the coastal region by the transgressing sea which reached a position approximately 100
feet above present sea level. It was probably during this late Pleistocene transgression that upper Pleis-
tocene fossiliferous sands were deposited along parts of the shore of San Diego County. Too few facts
have been obtained as yet to attempt a correlation of the steps in the Pleistocene history of this region
with that of other regions, such as the Palos Verdes Hills near San Pedro or the terraces along the
Malibu coast so interestingly discussed by Davis.

The latest physiographic events appear to be the slow reduction of sea cliffs and beach embank-
ments, the construction of spits and bars and the growth of small deltas in bays and lagoons. As a
whole, the coast now appears to be sinking slowly. This might be local or it might represent an eustatic
rise of sea level.

This sequence of events in the post-Pliocene history of the San Diegan region must be considered
largely hypothetical and unproved. Until much detailed field work can be accomplished little more
can be said that is not largely speculative or at least based upon inadequate facts.

GENERAL RELATIONSHIPS TO OTHER REGIONS

The San Diegan region, whose physiography has just been briefly discussed, is a small part of
what Fenneman!” has referred to as the Lower California Province, and what Reed'’® has included in the
Peninsular Ranges Province. The westward tilted and rejuvenated mountainous part of San Diego
County has some similarity to the tilted fault block of the southern Sierra Nevada in east central
California, but the eastern margin of the mountains in San Diego County is a more complex and ir-
regular escarpment than that defining the eastern precipitous slopes of the southern Sierra Nevada
and the rocks represented and their structures are only similar in part. However, in both regions old
sedimentary rocks have been intruded by acidic plutonic rocks which may be of approximately the
same age. The similarity of the Peninsular Range in San Diego County to the Santa Ana Mountains
in Orange County is probably closer, although here again there are many important dissimilarities.
Fairbanks, Hudson and others have mentioned the similarity and probable equivalence of some of the
schists of the Cuyamaca Mountains of San Diego County with certain schists in the Santa Ana
Mountains. The latter range is believed to be a fault block tilted westward by a fault zone along its
eastern base. The San Pedro Martir Mountains, which form the mountainous backbone of the
northern part of Lower California, Mexico, have been but little studied geologically but they appear
to be an extension of the same general physiographic complex.'"'

The San Diego Mesa extends for some distance into Lower California, Mexico. Farther south
extensive flows of vesicular lava have produced mesas which continue with interruptions as far as
Ensenada, but only their general relationship to the San Diego Mesa was investigated by the authors.
Other coastal terraces further south may be similar or actual physiographic equivalents.

The Tertiary strata of San Diego County are much thinner and less folded and faulted than
those of the Los Angeles and Ventura Basins. The less disturbed structure of the Tertiary strata in
the San Diego region may be due to their thinness and to the resistant nature of the crystalline rocks
upon which they were deposited. The total absence of marine Oligocene and Miocene sediments is a
striking feature. Correlations of the Pleistocene terraces of San Diego County with other California
coastal regions may be possible in the future, but the basis of such correlations can only be obtained

109 Fenneman, Nevin M., “Physiography of Western United States,” (New York, 1931), pp. 508-510, and map of
Physiographic Provinces.

110 Reed, Ralph D., “Geology of California,” (Tulsa, Oklahoma, 1933), pp. 20-22, map fig. 1.

111 See Woodford, A. O., and Harris, T. F., “Geological Reconnaissance Across Sierra San Pedro Martir, Baja California,”
Bull. Geol. Soc. Amer., Vol. 49, no. 9, pp. 1297-1336, 5 figs., 7 pls., Sept. 1, 1938.

32 San Disco Society of Naturat History [Memorrs

by much more field work than has been accomplished up to this time. Various fault blocks may have
had a somewhat independent and individual history, so that long distance correlations may be, in most
cases, very difficult if not entirely impossible.'’”

PRE-TERTIARY IGNEOUS AND METAMORPHIC ROCKS

The Tertiary sedimentary formations of the San Diego region are bordered on the east by a
series of volcanic breccias and agglomerates which are believed to be of Triassic age. While there is
no local paleontologic evidence upon which an age determination can be based, the northern extension
of this foothill belt of ancient rocks was thought by M. A. Hanna'!’ to be very similar in general
characters to the dark gray or black slates and associated dikes and effusives which form the axis of
the Santa Ana Mountains some miles to the north. These latter rocks were studied by Mendenhall’
who collected from them specimens of Rhynchonella, Spiriferina, Terebratula, and fragments of crinoid
stems determined by Stanton as of Triassic age.

The breccias and agglomerates of the San Diego region have not been observed in contact with
the Cretaceous beds by the present authors, nor by Hanna in the area immediately adjacent to the north.
As stated by Hanna, however, the Eocene can be observed to rest upon the eroded surface of the ag-
glomerates, and because of this relation it is reasonable to assume that the Cretaceous likewise rests
upon an erosion surface of these pyroclastics. Further evidence of the considerable age of these
agglomerates is their relationship to a quartz diorite batholith which has been intruded into them.
In the Grossmont-Mount Helix region just east of La Mesa the diorite mass contains numerous xeno-
liths of the dark, dense agglomerate or pyroclastic rocks which determine their age as pre-batholithic.
A few miles north of La Mesa, Hanna (i526, p. 200) has observed roof pendents of these older rocks
surrounded by the quartz diorite.

In the region covered by the present report the agglomerates appear to occur in a band of varying
width along the western margin of the quartz diorite batholith. This band extends from the north-
eastern portion of the area mapped, in a south-southeasterly direction to and probably beyond the
Mexican Boundary.

East of this band of old agglomerates and volcanics a quartz diorite batholith is the most im-
portant country rock. This plutonic rock has intruded a considerable number of other rocks, some of
which are schists which may have been ancient Paleozoic sediments. Fairbanks''’ gave an interesting
account of the geology of the mountains of San Diego County in a report published by the California
State Mineralogist in 1893. In his report, which includes a large number of field observations and
determinations of igneous and crystalline metamorphic rocks, it appears that the region is a complex
one petrographically. Fairbanks (1893, p. 116) mentioned the discovery in the Santa Ana Mountains
of a gray limestone containing “fine specimens of a bivalve shell, and faint traces of corals and univalve
shells” which were determined at the U. S. National Museum as of Carboniferous age. As pointed
out by Hudson,''® these fossils probably came from Ladd Canyon and were the ones which J. P.
Smith'”” once considered probably lower Triassic in age. Later Smith''® named the bivalve Daonella

112 In a recent paper, W. M. Davis (Proc. Nat. Acad. Sci., Vol. 18, no. 11, pp. 659-665, 8 text figs., Nov., 1932; Bull.
Geol. Soc. Amer., Vol. 44, no. 5, pp. 1041-1133, 26 text figs., 16 pls., Oct., 1933) has given an interesting description of the marine
terraces along the Malibu coast of Los Angeles and Ventura Counties, with a suggestion of a correspondence with the glacial
chronology of the Sierra Nevada. Even if these terraces were due entirely to periodic eustatic changes in the level of the sea, which
is not proved, their correspondence to terraces on other land blocks some distance away may be confused or entirely obscured by
diastrophism in the second region. Lack of abundant fossils on these Quaternary terraces generally makes paleontologic correlations
impossible. All the terraces in the Malibu region discussed by Davis are, in all probability, late Pleistocene and therefore they do
not represent the major glacial sub-epochs of Pleistocene times.

113 Hanna, Marcus A., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 16, no. 7, p. 203, 1926.

114 Mendenhall, W. C., U. S. Geol. Surv., Prof. Paper 71, p. 505, 1912.

115 Fairbanks, H. W., Calif. State Mining Bureau, 11th Ann. Rept. State Mineralogist, pp. 76-119, 1 map, 1893.

116 Hudson, F. S., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 13, no 6, pp. 188-189, 1922.

117 Smith, J. P., Proc. Calif. Acad. Sci., Ser. 3, Vol. 1, p. 352, 1904.

118 Smith, J. P., U. S. Geol. Surv., Prof. Paper 83, p. 145, 1914. Daonella sanctae-anae Smith is figured on pl. 1, figs.
12-14. In regard to horizon and locality of this species, Smith stated (p. 145): “Rare in the Middle Triassic, near the head of
Silverado Canyon (probably Bedford Canyon), Santa Ana Mountains, Orange County, Cal., associated with Rhynchonella sp.
undt., and a rough-shelled ammonite not definitely determinable. Collected by H. W. Fairbanks.”

VotuME II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 33

sanctae-anae and, presumably due to the apparent close relationship of this new species to Daonella
béckhi Mojsisovics of the middle Trias of the Alpine Province, he referred the beds from which
this species was collected to the middle Triassic. In the meantime Stanton had concluded that the
Ladd Canyon fossils could be taken to “clearly indicate the Triassic age of the fauna,” which he
believed was “probably upper Triassic rather than older.” The importance of the age determination
of these Santa Ana Mountains schists and associated limestone’? is that they appear to be equivalent
to some of the metasedimentary rocks of the mountains further south in San Diego County, as early
suspected by Fairbanks.

Hudson’”’ has contributed an important paper on the crystalline rocks of the Cuyamaca region in
San Diego County. This paper was a result of his study of the gold deposits which had been mined there.
He states (p. 181) : “The rocks exposed at the surface over a large part of the mountainous region of
San Diego County are quartz-bearing plutonic rocks, varying from quartz diorite to true granite in
composition. The relation of these rocks to the older rocks which they have intruded shows that the
intrusion was of batholithic nature. Most of the cover has been stripped from this batholith, the
older rocks being found as remnants, surrounded by granite. These older rocks are schists, the result
of metamorphism of shales and sandstones, with subordinate layers of lava.” In the Cuyamaca region
Hudson reports the occurrence of basic plutonic rocks, such as basic diorite, gabbro and norite, as well
as pegmatites which, in parts of San Diego County, are important sources of gem minerals such as
Tourmaline, Kunzite, Beryl, etc. In regard to the date of intrusion of the quartz diorite Hudson
states: “The quartz-diorite batholith was developed in post-Triassic time and is probably equivalent
to the post-Mariposa intrusions of the Sierra Nevada.”

A number of short papers have appeared from time to time bearing on minerals or special rock
types occurring in San Diego County. Among them may be mentioned papers by Lawson, Schaller
and others. References to these papers may be readily found in the various bibliographies by Nickles'*!
and Shedd.'** An excellent brief summary of the crystalline rocks of San Diego County appears in
an important work by Reed'” on the geology of California. More recently Miller'’* briefly described
the geology of a section across a portion of San Diego County. In this paper he described principally
the igneous and metamorphic rocks observed in an area contiguous to the highway through La Mesa,
Descanso, Jacumba to just beyond Mountain Springs in Imperial County.

Igneous rocks are rare in the coastal region of San Diego County. However, it is of interest to
note that Blake'” reported the presence of a dike of greenstone along the southeast side near the
southern end of Point Loma. Although we have not seen this dike we believe the sedimentary beds
cut by the intrusion are of Cretaceous age. A basaltic dike said to be from two to thirty feet thick
occurs about a quarter of a mile north of the pier of the Scripps Institution of Oceanography and
about 214 miles north of La Jolla. It cuts the Rose Canyon shale and is exposed along the beach but
does not extend to the top of the high bluff. It is the only igneous intrusion in the Eocene of which we
are aware in this region. It has been described by Fairbanks'*® and by M. A. Hanna.'”” The only

119 H. W. Hoots (U. S. Geol. Surv., Prof. Paper 165-c, pp. 88-89, 1931) referred the Santa Monica slate of the eastern
part of the Santa Monica Mountains (Los Angeles County) questionably to the Triassic, “in view of its similarity to the fossiliferous
Triassic slate of the Santa Ana Mountains, both in lithologic character and in its relations to fossiliferous Cretaceous rocks and an
earlier granitic intrusion.” It might be mentioned that the Santa Monica slate, which is a formation characterized chiefly by its
total lack of recognizable fossils and its rock cleavage parallel to the original bedding planes, bears considerable resemblance to
some phases of the Franciscan formation of the coast ranges of middle and northern California (probably of Jurassic age in part)
and likewise to some statically metamorphosed argillites and phyllites, with cleavage parallel to the bedding planes, occurring in
parts of the Mojave Desert and, by their geologic relations, believed to be of pre-Cambrian age. The similarity of these latter
mentioned rocks was called to our attention by Professor A. R. Whitman.

120 Hudson, F. S., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 13, no. 6, pp. 175-252, 7 text figs., 1 map, pls. 9-14,
June 29, 1922.

121 Nickles, J. M., U. S. Geol. Surv., Bull. 746, 1923; Bull. 747, 1924; Bull. 823, 1931.

oe Hi Shedd, S., State of California, Dept. Nat. Resources, Division of Mines, Geologic Branch, Bull. 104, 1933; Bull.
GEE Reed, R. D., “Geology of California,” published by the Amer. Assoc. Petrol. Geol., Tulsa, Oklahoma, May, 1933.

124 Miller, W. J., “A Geologic Section Across the Southern Peninsular Range of California,” Calif. Journ. Mines and
Geology, Vol. 31, no. 2, (31st Rept. State Mineralogist), pp. 115-142, 8 text figs., 1 plate (geologic map and sections), 1935.

125 Blake, W. P., U.S. Pacific R. R. Repts., Vol. 5, p. 176, 1856.
126 Fairbanks, H. W., 11th Ann. Rept. Calif. State Mineralogist, pp. 96-97, 1893.
127 Hanna, M. A., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 16, no. 7, p. 224, 1926.

34 San Dreco Society OF NatTuraL History {Memoirs

indication in this region of igneous activity during Eocene time is the rare occurrence of ash beds
in the Poway conglomerate. The occurrence of bentonite in this region is mentioned in the discussion
of the Pliocene sediments in the present paper.

During the course of the field work in this area, the authors collected a number of hand specimens
of rock from the granitic batholith and from the volcanics and agglomerates to the east of the Pliocene
beds. Thin sections of twelve of these specimens were made by Hochgesang and Vogel in Goettingen,
Germany. The hand specimens were studied by the late Dr. John E. Wolff of Pasadena, California,
and the thin sections were studied by Dr. Wolff and by Dr. Gordon A. Macdonald whose reports

are included here. Their names accompany the descriptions which each has furnished.

No. 1. From south side of Sweetwater Dam, close to the upper part of the dam:

Hanp Specimen. Dark gray, dense, breccia, the rock fragments even smaller than in No. 2.

Section. The rock fragments are the same as those of Nos. 2 and 3, i.e., fine-grained feldspar or quartz
feldspar lavas, often graphic, but one is a fine-grained granite porphyry, with phenocrysts of quartz and feldspar
in a microgranitic groundmass, and another is perhaps a silicified tuff from the same rocks. The cement has
broken fragments of the same rocks, quartz feldspar, occasional fragments of ferromagnesian minerals now re-
placed by epidote, calcite and iron ore; large areas of calcite and epidote, the base of the cement, as before, fine
silica grains and sericite. (J. E.Wolff).

No. 2. From foundation rock of Sweetwater Dam, taken from north side, 6 to 9 feet from the
top of the concrete work. This rock weathers light buff gray or becomes stained brownish red from
iron oxide.

Hanp Specimen. A dense dark gray breccia, with small fragments of rock, biotite or chlorite, and frequent
small masses of pyrite.

Section. Finer-grained than No. 3. The rock fragments are smaller, but essentially the same, of fine-
grained quartz feldspar graphic inter-growths, with occasional phenocrysts of orthoclase and plagioclase. The
cement again essentially a fine-grained quartz aggregate and plates of sericite, with broken feldspar (orthoclase
and acid plagioclase fragments), pyrite and magnetite areas, much epidote, sericite, etc., in the altered feldspars;
chlorite, clastic augite, sometimes replaced by uralite, calcite, quartz fragments. (J. E. Wolff).

No. 3. Breccia from south side of upper Las Choyas Valley, just south of the V in valley:

Hanp Specimen. Small fragments of feldspar, etc., in a dark gray, quartzitic groundmass.

Section. A number of large and small rock fragments in a cement. The rock fragments are largely of fine-
grained igneous rocks, having fine feldspar laths in flow structure, with or without quartz between. Some seem
identical with the alaskite-porphyry, below, others are pure feldspar, a plagioclase too fine to determine, one of
fine-grained biotite granite, and others composed of fine interlocking quartz grains, a quartzite or chert, others
contain larger angular grains of quartz and feldspar in the same fine quartz aggregate—a silicified arkose or tuff.
Also a limonitized limestone. The cement of the tuff has small similar rock fragments, fragments of quartz and
feldspar, much epidote, chlorite, limonite and so forth, the ultimate cementing material minute grains of quartz

and sericite. (J. E. Wolff).

No. 4. Rock samples from west side of Lower Otay Dam:

Hanp Specimen. A dense dark gray flinty rock, through which ill-defined and evidently altered feldspar
phenocrysts are scattered.

Section. The feldspar phenocrysts are orthoclase and a plagioclase probably albite, much decomposed, with
epidote, quartz, calcite as products. One or two bunches of secondary green hornblende may represent original
augite. The groundmass has small slender feldspars, largely albite-oligoclase, probably orthoclase, with quartz
filling, and decomposition products. The rock is probably identical with No. 8, but much changed, i.e., an
alaskite-porphyry. (J. E. Wolff).

No. 5. Sample from hillside about 1 mile west of Sweetwater Dam:

Hanp Specimen. Dense dark gray with little pyrite areas common and small phenocrysts of feldspar.

Section. Large phenocrysts of colorless augite, largely replaced by epidote aggregates, and of basic oligoclase,
also epidotized. The groundmass is composed of small laths of oligoclase, scattered in what was once a glass,
now a mass of granular decomposition products. The rock is probably an augite-andesite? (J. E. Wolff).

No. 6. One-half mile southwest of Grossmont High School, on north slope of Grossmont, just
above foot of the mountain:
Hanp Specimen. A coarse-grained, feldspar-rich and hornblende-poor rock, containing patches of a finer-

grained more basic feldspar-hornblende rock, in which a rough ratio is two hornblende to three feldspar. (J. E.
Wolff).

Votume II) MariINE PLIOCENE OF SAN DIEGO, CALIFORNIA 35

Section. Coarse-grained facies: Hypidiomorphic texture. Plagioclase is the most abundant constituent, and
shows well-developed zoning, from acid labradorite in the center to oligoclase on the outside. Intersticial quartz
is abundant. The ferromagnesian minerals are green hornblende and less abundant brown biotite. Minor accessory
minerals include abundant magnetite, less abundant apatite and titanite, and a few crystals of zircon.

Fine-grained facies: A basic inclusion, composed of the same minerals as the coarse-grained rock, but with
a greater percentage of dark minerals, and a smaller amount of biotite in relation to hornblende. A little orthoclase
is also present, as large crystals carrying poikilitic inclusions of andesine and hornblende.

The rock is a hornblende-biotite quartz diorite, containing basic inclusions of schlieren. In the San Luis Rey
quadrangle just to the north, Hurlbut (Amer. Mineralogist, Vol 20, pp. 609-630, 1935) considers the dark
schlieren to have been derived by reaction of the quartz diorite with xenoliths of the older San Marcos gabbro.
(G. A. Macdonald).

No. 7. West slope of Grossmont, about one-half way up, just east of La Mesa:

Hanp Specimen. Fine-grained pinkish biotite-granite. Scattered feldspars are decomposed to limonite.
(J. E. Wolff).

Section. The texture is hypidiomorphic. Essential minerals are orthoclase and quartz, with a little micro-
cline, and a subordinate amount of oligoclase. The ferromagnesian mineral is brown biotite. Accessory minerals
include magnetite, apatite, titanite, and zircon, the latter enclosed in the biotite and surrounded by pleochroic halos.
The biotite is in subhedral plates, and the oligoclase varies from subhedral to nearly euhedral in outline. Orthoclase
varies from subhedral to anhedral. The quartz was clearly the last mineral to crystallize, occurring as anhedral
grains intersticial to the other components. The rock is slightly altered; the orthoclase shows traces of kaolinization,
and a few of the biotite flakes are partly changed to chlorite.

The rock is a biotite granite. (G. A. Macdonald).

No.8. First hard rock outcrop on hillside, east margin of Otay Mesa, at east end of main east-
west road:

Hanp Specimen. A lighter gray and coarser rock than No. 9; numerous small phenocrysts of feldspar.
Limonitized pyrite grains. (J. E. Wolff).

Section. Porphyritic, with phenocrysts of albite in a groundmass composed of small laths of albite and
intersticial quartz. Small, irregular areas of epidote, chlorite, and calcite are scattered through the slide. A little
magnetite is present.

The larger phenocrysts, which Wolff identified as orthoclase, show a positive sign, with 2V about 75° and
an index lower than balsam, and are certainly albite.

The rock is an albitite. (G. A. Macdonald).

No. 9. From north slope of 667 foot hill, north side of Otay Valley about 314 miles west from
lower Otay Dam:

Hanp Specimen. A dark gray, fine-grained rock, showing small crystals of feldspar, small specks of pyrite
common, and large vein-like or concretionary masses of pyrite, quartz and a white granular mineral. (J. E. Wolff).

Section. The rock is very much altered, but I believe it represents a propylitized andesite. Phenocrysts of
some femic mineral, probably augite, have been changed to epidote and chlorite. The feldspars have been saus-
suritized, and are now represented by mixtures of albite, epidote, chlorite and calcite. There are also present
abundant fine, irregular grains of iron ore, some of them no doubt original, but many being separated out during
the change of the femic minerals to chlorite, with which they are closely associated. (G. A. Macdonald).

No. 10. About 300 yards east of Isham Springs, Sweetwater Reservoir :

Hanp Specimen. A dark flinty rock with irregular pinkish-white areas evenly distributed in a dark gray
groundmass.

Section. The rock is mainly composed of a fine, interlocking aggregate of quartz grains, in which are
scattered fragmentary crystals of larger size feldspars, mostly andesine, also patches of muscovite or chlorite plates,
little grains of ore, often with associated rutile crystals, much epidote. The feldspars are clastic, the rest meta-
morphic, an altered sediment, perhaps a tuff. (J. E. Wolff).

No. 11. About 34 mile north of Aloha, edge of mesa, north of Sweetwater Valley:

Hanp Specimen. Dark gray, fine-grained basaltic rock, small phenocrysts of feldspar.

Secrion. Small phenocrysts of a very basic labradorite (bytownite) are common, and a few of augite. The
groundmass is composed of similar feldspars in flow structure, and small grains of augite and magnetite, with
perhaps a very little interstitial glass here and there. Epidote, chlorite and other alteration products. The rock
is a feldspar basalt. (J. E. Wolff).

No. 12. In road pass about 114 miles east of summit of Mount Helix:

a Tia Specimen. A fine-grained, biotite-rich, granitic rock; the feldspars have a slight lilac color. (J. E.
olf).

36 San Disco Society oF Natura History [Memotrs

Secon. Hypidiomorphic texture. Essential minerals are andesine, orthoclase, and quartz. The andesine
shows distinct zoning, varying from intermediate andesine (An,,) in the center to acid andesine (An,,) on the
outside. The andesine is much more abundant than the orthoclase. Ferromagnesian minerals include green
hornblende and brown biotite, in part intergrown. Many of the hornblendes contain a central core of diopsidic
augite, the c crystallographic axis in the augite being parallel to that in the enclosing hornblende. The properties
of the augite are: (+-)2V = 60°, very weak, Z c = 40°. Minor accessories are magnetite, apatite, zircon, and
titanite. Some of the biotite is slightly chloritized.

The rock is a hornblende-biotite quartz diorite. Wolff’s designation of the rock as a granodiorite seems to
me undesirable, since a granodiorite should contain about half as much orthoclase as it does plagioclase, while
this rock carries very much more abundant plagioclase than it does orthoclase. (G. A. Macdonald).

No. 13. Igneous rock outcropping 14 mile north of Aloha and 5 mile W-NW of Sweetwater

Hanp Specimen. The rock is a fine-grained, dense, greenish-gray basalt.

Section. Microscopically, it consists of phenocrysts of labradorite and diopside in a pilotaxitic groundmass
of labradorite laths and grains of serpentinized diopside, with abundant small grains of magnetite. The feldspar
phenocrysts are slightly zoned, varying from medium labradorite in the center to acid labradorite on the edges.
Some oscillatory zoning is present. The feldspar microlites in the groundmass are acid labradorite. Diopside
is very largely altered to serpentine, usually showing a net structure; but a few grains of diopside remain un-
altered. (G. A. Macdonald).

Of these rock specimens Nos. 6, 7 and 12 are from the granitic batholith, while the others are
from the volcanics and agglomerates. Nos. 1, 2 and 3 appear to be much altered tuffs, probably
originally of andesitic nature. Nos. 4 and 8 are albitite, Nos. 5 and 9 altered augite andesites, No. 6 a
quartz diorite, No. 7 a biotite granite, No. 10 probably a tuff, Nos. 11 and 13 are basalts, and No. 12
a diorite.

CRETACEOUS

Marine beds of Cretaceous age which underlie the Eocene in the area under discussion are exposed
at only a few places. They are found principally near the coast, due to the fact that the Eocene strata
over most of the area have not been elevated sufficiently to permit recent erosion to cut through to the
lower beds. In the La Jolla Quadrangle, M. A. Hanna’’® discussed the Cretaceous deposits which are
exposed along the coast from about one-half mile north of False Point to north of the City of La Jolla,
and also on the north slope of Mount Soledad. These beds, which were referred to the Chico, upper
Cretaceous age, are about 500 feet thick and consist of shales and sandstones of varying hardness.
The Cretaceous sandstones forming the terrace upon which La Jolla has been built are resistant to
erosion, but joints, faults and irregular induration have permitted wave action to produce numerous
caves and small coves due to the more rapid removal of the softer material. Eocene rocks unconformably
overlie the Cretaceous beds in that area.

Farther south, on the west side of Point Loma from west of the Theosophical Institute up to and
including the southern point of the peninsula, Cretaceous shales and sandstones are well exposed close
to the water’s edge. Fairbanks’’’ briefly discussed the geology of Point Loma and referred briefly to
these Cretaceous beds. He assigned the beds at the southern end of Point Loma to the Chico, upper
Cretaceous, but supposed the heavy overlying conglomerates to be of late Tertiary age,'*® whereas it
seems more probable that they belong to the upper Eocene. They apparently unconformably overlie
the Cretaceous strata.

At the extreme south end of Point Loma, a thin-bedded bluish gray shale occurs at the base of
the cliff. ‘These strata are well exposed for over a hundred yards east of the small cave near the
lighthouse. The dip of these beds is about 11° toward the east, and they soon disappear beneath the
rocky beach. In these shales the authors collected a few specimens of Baculites and fossils of a plant
identified by Dr. L. M. Waitzinger as a conifer of ancient type. From this locality (Loc. 1173 C.A.S.)

128 Hanna, M. A., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 16, no. 7, pp. 205-207, 1926. — See also, Hertlein,
L. G., and Grant, tv, U. S., Calif. Journ. Mines and Geol., Vol. 35, no. 1. 35th Rept. Calif. State Mineralogist, pp. 62-65, Jan.,
1939 [received at library of the California Academy of Sciences, Aug. 23, 1939].

129 Fairbanks, H. W., Calif. State Mining Bureau, 11th Ann. Rept. Calif. State Mineralogist, pp. 94-96, 1893.

130 Fairbanks (1893, p. 96), however, did report the occurrence of Eocene fossils in the low bluffs at the northeast end of
Point Loma.

VotumE IT] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 37

Mr. C. C. Church, paleontologist with the Tidewater Associated Oil Company, has identified fora-
minifera in a sample of dark gray shale. He has submitted to us the following report on these
foraminifera :

The foraminifera listed here were concentrated from gray shale collected by Dr. L. G. Hertlein in September,
1928. The preservation is good but the total number of specimens recovered is small. For the number of specimens
the list of genera is relatively short. The species are as follows:

Anomalina sp.

Allomorphina cf. minuta Cushman

Bulimina obtusa d’Orbigny

Globotruncana arca Cushman

Gyroidina sp.

Gaudryina (Pseudogaudryina) pyramidata Cushman
Gaudryina oxycona Reuss

Marginulina humilis Reuss

Robulus sp.

Spiroplectammina anceps Reuss

These foraminifera are commonly found near the middle of the upper Cretaceous, that is, below the Moreno
and probably in the upper half of the Panoche group of F. M. Anderson.

The Eocene beds overlying the Cretaceous at Point Loma are composed of sandstones and con-
glomerate. These Eocene beds at one place near the point dip about 30° to the east-southeast.
Boulders made up of sandstone are present, and near the top huge boulders occur which apparently
came from the crystalline rocks many miles to the east. Both the Cretaceous and Eocene are cut by faults.

A number of species have been listed from the Cretaceous of Point Loma by Cooper’*! and
Anderson.” The published lists of the species from that locality are in need of revision, as some
of the species cited are now known to occur in the Eocene or at other localities in the Cretaceous
and not at Point Loma.

The list here given has been compiled from published lists and from collections in the California
Academy of Sciences.

BRACHIOPODA
“Waldheimia” imbricata Cooper

PELECYPODA
Acila demessa Finlay
Coralliochama orcutti White
Crassatellites lomana Cooper (type locality)
Cymbophora ashburnerii Gabb
Glycymeris veatchii Gabb
Inoceramus sp.
Lima appressa Gabb
Nemodon vancouverensis Meek
Opis triangulata Cooper (type locality)
Pholadomya brewerii Gabb
Protocardium placerensis Gabb
Tellina decurtata Gabb
Tellina whitneyi Gabb
Trapezium carinatum Gabb
Trigonocallista varians Gabb

GASTROPODA
Acteonina pupoides Gabb
Cerithium pillingi White
Gyrodes conradiana Gabb
Haliotis lomaénsis Anderson (type locality)
Oligoptycha obliqua Gabb
Patella cf. traskii Gabb

131 Cooper, J. G., Calif. State Mining Bureau, Bull. 4, pt. 5, pp. 60-63, 1894. See also, Cooper, A. S., Calif. State Min.
Bur., Cat. State Mus. Calif., (Sacramento), Vol. 5, pp. 118-122, 1899.
132 Anderson, F. M., Proc. Calif. Acad. Sci., Ser. 3, Geology, Vol. 2, no. 1, pp. 27-32, 1902.

38 San Dreco Society oF NaTuraL History {[Memorrs

CEPHALOPODA
Baculites fairbanksi Anderson
Hamites vancouverensis Meek
Heteroceras cooperii Gabb (type locality)

Parapachydiscus catarinae Hanna and Anderson

This assemblage indicates an upper Cretaceous age, probably Campanian, upper Senonian.

Mr. Frank Stephens and Mr. Cecil V. Robinson discovered a new Cretaceous fossil locality near
the southern end of Point Loma which has yielded specimens of Parapachydiscus catarinae Hanna and
Anderson,'**? Coralliochama orcutti White,'** Volutoderma gabbi White, Inoceramus sp. and other
mollusks. The Parapachydiscus and the Coralliochama also occur in the northern district of Lower
California, the Parapachydiscus in the Santa Catarina region and the Coralliochama at Punta Banda,
Lower California, Mexico. The Parapachydiscus also occurs in the upper Cretaceous north of Coalinga,
Fresno County, California. These occurrences indicate that this Parapachydiscus zone is of considerable
importance for purposes of correlation.

A well drilled by the Borderland Exploration Company on Point Loma gives some definite data
on the thickness of the Cretaceous beds at that locality. This well, which was known as Point Loma
No. 1, was located on Pueblo Lot No. 211, section 30, Township 16 South, Range 3 West, San
Bernardino Base and Meridian, and was drilled to a depth of 5,101 feet. The log furnished through
the courtesy of G. D. Hanna and C. C. Church is as follows:

1,560 feet. Core. Hard gray sandy shale; plant fragments.

1,580 feet. Core. Hard gray sandy shale; plant fragments, foraminifera, fragments of Inoceramus and
ammonites.

1,680 feet. Core. Hard gray sandy shale; plant fragments and ammonite fragments.

1,787 feet. Core. Hard gray sandy shale; plant fragments.

1,885 feet. Core. Hard gray sandy shale; plant fragments.

1,945 feet. Core. Hard gray sandy shale; fragments of Baculites chicoensis Trask.

2,000 feet. Core. Hard gray silty clay shale; foraminifera rare and small, Textularia, Silicosigmolina, Mar-
ginulina. Foraminifera in core appear to be Cretaceous, but determination not certain.

2,010 feet. Core. Hard gray sandy shale; plant fragments.

2,100 feet. Core. Coarse greenish pebbly sandstone.

2,250 feet. Bit. Gray fine to coarse sand and shale; no fossils.

2,500 feet. Core. Hard gray sandy shale; plant fragments, foraminifera and a large piece of an ammonite.

2,771 feet. Core. Hard reddish brown sandstone with pebbles; marked “top of red beds.”

3,110 feet. Core. Hard red sandstone.

3,670 feet. Core. Hard red conglomerate; pebbles up to 3 inches. All samples with fossils are Cretaceous.
The red beds are of uncertain age; nothing similar to this in West Coast Cretaceous,
so may be older.

3,735 feet. Core. Hard greenish-gray altered rock, probably metamorphosed rhyolite or similar form. In
thin flakes under the microscope the substance is seen to be translucent. It contains
no sand or quartz and does not belong to the granite series. Pyrite and calcite are
found in seams and the rock itself contains some mineral which reacts like dolomite
in hot acid, although the proportion is small.

3,828 feet. Core. Greenish-gray, partially crystalline, limy, altered rock with veinlets.

3,857-58 feet. Core. Brown loose fine sand; no fossils. The brown sand of the last sample is so loose as to
seem out of place with the dense limy rock a few feet above it. No fossils were noted
to indicate the possible age of the material.

133 Hanna, G. D., and Anderson, F. M., Pan-American Geologist, Vol. 50, no. 4, p. 283, pl. 9 (larger shells in the
illustration), Nov., 1928. Name and figure only. “. .. from a few miles southwest of Santa Catarina, and from the uppermost
beds of the Cretacic section exposed there.” Lower California. — Anderson and Hanna, Proc. Calif. Acad. Sci., Ser. 4, Vol. 23,
no. 1, p. 19, pl. 1, fig. 1, pl. 2, fig. 1, pl. 3, figs. 1-3, Dec. 23, 1935. “Near Santa Catarina Landing, Lower California.” Upper
Senonian, upper Cretaceous. — Johnson, M. E., “West Coast Shells,” (Edwards Brothers, Inc., Ann Arbor, Michigan), 1937, p. 38,
fig. 114 (figure at right). Near Catarina, Lower California.

134 For references to Coralliochama orcutti White see Anderson, F. M., and Hanna, G. D., Proc. Calif. Acad. Sci., Ser. 4,
Vol. 23, no. 1, p. 31, 1935. Definitely recorded from Point Loma and La Jolla, Calif. H. W. Fairbanks (1893, pp. 95, 96) recorded
the species from the same localities, and Stearns (Science, New Ser., Vol. 12, no. 294, p. 248, Aug. 17, 1900), also recorded the
species from La Jolla.

Rudistids are comparatively rare in the Cretaceous of western North America. Packard and Lupher have described two
rudistids, one from the Jurassic, and one from the Cretaceous of Oregon (Univ. Oregon Publ. Geol. Ser., Vol. 1, no. 3, pp. 203-212,
6 pls., issued Dec. 30, 1929), Orcutt stated (Jamaica Nat., Vol. 1, no. 1, 1927, p. 3), that the genus Coralliochama had been
reported from Washington.

VotumE II] MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 39

4,290 feet. Core. Light gray, hard, fine-grained crystalline rock with seams of calcite. This confirms the

determination made higher in the well that the formation is non-sedimentary.

This well was drilled to 5,101 feet, where brownish gray shale and sandstone were logged.

From this log it appears that the marine Cretaceous beds (“Chico”) at this locality are not more
than 1,211 feet thick. If the red beds (964 feet) are non-marine Cretaceous, as seems likely, then the
total thickness of the Cretaceous here is not more than 2,175 feet.

The log of the Holderness well, near the mouth of the Tia Juana River, given in a later part of
the present paper (page 59) shows that the marine Cretaceous is not more than 1,360 feet thick in
that area. The underlying red beds,'”” 269 feet thick, may be non-marine Cretaceous, in which case
the total thickness of Cretaceous beds in that area would be 1,629 feet. The dip of the beds penetrated
by the wells is unknown to us and therefore their exact maximum stratigraphic thickness is unknown.

Information from Mr. Donuil Hillis, geologist with the Capital Company, San Francisco, and
Dr. A. L. Tull, San Diego, on Capital No. 1 Well was recently made available to us. This well is
stated to be “150 feet east and 547 feet north of the southwest corner of Pueblo Lot 1237, which
would be in the Projected Section 32, of Township 15 South, Range 3 West” (Hillis). According
to Mr. Hillis (letter to U. S. Grant, 1v, dated at San Francisco, September 11, 1942), Dr. Tull
believed the Cretaceous was encountered at a depth of 4,400 feet and the well was still in rocks of
that age at 6,130 feet. The data supplied by Mr. Hillis and Dr. Tull indicate a considerably greater
thickness of both Eocene and Cretaceous than that known from the outcrop sections. Due to the fact
that the Cretaceous lies upon an uneven erosion surface it is likely that thicknesses will vary considerably.
This well is near Rose Canyon, where folding along the Soledad anticline might give a somewhat
exaggerated stratigraphic section in a well.

The following additional information on Capital No. 1 Well was provided by Mr. Charles H.
Reed, Secretary-Engineer, Bureau of Mines of San Diego County, in oral statements to Mr, Clinton
G. Abbott on March 3, 1943, and a letter to him on April 30, 1943. The formations encountered in
drilling were entirely sedimentary. The ultimate depth of 6,130 feet is deeper than any other well
ever drilled in San Diego County except one at Imperial Beach, which struck salt water at 6,400 feet.
On March 3, 1943, there were 850 feet of fluid in the bottom of Capital No. 1 Well, of which 30%
was water and 70% was oil of 24.8 gravity. The temperature of the water was 168°F. Mr. Reed
believed that strata producing oil and gas were penetrated by the well between the depths of 5,904
and 6,130 feet. He further stated that drilling was suspended about the latter part of August, 1942,
and that, due to mechanical difficulties, it was impossible to drill the well deeper.

Many years ago a vertical shaft was sunk to a depth of about 125 feet on the terrace on the
west side of Point Loma, approximately one and three-fourths miles north of the present lighthouse,
in search of coal.!2° It is said that several strata of coal were penetrated, one of them being five feet
thick and having a dip toward the east.'? Although we visited the entrance to this shaft we were

135 These red beds may be a southern extension of the Trabuco formation in the Santa Ana Mountains, Orange County,
Calif. This formation was named by E. L. Packard, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 9, no. 12, p. 140, Feb. 8,
1916. See also, Popenoe, W. P., Journ. Geol., Vol. 49, no. 7, pp. 738-752, 1941.

The red conglomerate resting on the diorite at Punta Banda, on the south shore of Todos Santos Bay, about seventy-five
miles south of the United States-Mexico Boundary, may likewise represent the Trabuco formation. At that locality the fossiliferous
Cretaceous is in fault contact with the red beds.

136 The San Diego Herald (Vol. 5, Nov. 24, 1855, p. 2, col. 1), stated that coal was discovered by Ladd, Green, Tanner
and Serrine on the shore of the Pacific about two miles north of Point Loma. It was tested and found to burn with a clear
flame, and gave off intense heat. The following year the same paper (Vol. 5, Feb. 2, 1856, p. 2, col. 2), stated that the company
had bored 45 feet and passed through 10 or 12 different strata of coal, which varied from three inches to one foot in thickness.

Smythe wrote regarding this mine as follows:

“One of the most interesting episodes of the early days was the work of some Mormons, bent upon the enterprise of mining
coal on the north [west] shore of Point Loma, late in 1855, in response to a ‘revelation.’ Obtaining a lease of land from the city
trustees they proceeded to make borings which penetrated several strata of coal, ranging from three inches to a foot in thickness.
In April, 1856, they announced that they had discovered a vein of good coal four and a half feet thick near the old lighthouse on
Point Loma, and began to sink a shaft. Considerable machinery was installed and a few experienced miners, as well as engineers,
employed, but nothing came of the enterprise.” See Smythe, William E., “History of San Diego,” (The History Co., San Diego,
Calif., 1907), pp. 259-260.

A modern account of the history of this mine by Winifred Davidson (Mrs. John Davidson), occurs in the San Diego Union,
second section, Sunday Morning, Jan. 31, 1932, p. 2, col. 4, 1 illustration.

137 San Diego Herald, June 28, 1856, p. 2, col. 1.

40 San Disco Society oF Natura History [Memorrs

unable to determine whether the coal was of Eocene or Cretaceous age. That this shaft penetrated
beds of Cretaceous age, however, is certain since Gabb described “Ammonites” cooperii, an upper
Cretaceous form, “from a shaft sunk in search of coal on the west side of Point Loma, opposite La
Playa, San Diego.”'*® A map’”’ by C. B. Wadleigh published in 1888 bears the words “Coal measures”
in the ocean off this part of Point Loma.

A few miles farther north, coal was encountered in a boring at La Jolla which Fairbanks (1893,
p. 96) said must be Cretaceous in age. Cretaceous rocks are exposed there, but we have no later infor-
mation on the occurrence of this coal.

Blake reported the presence of a dike of greenstone along the southeast side of Point Loma.
We did not investigate this dike, but we believe that it cuts Cretaceous sediments. Another dike occurs
near the Scripps Institution of Oceanography north of La Jolla and cuts the Eocene rocks there.

EOCENE
In his report on the geology of the La Jolla Quadrangle Marcus Hanna’ briefly reviewed the

literature on that area and gave a complete list of references. Hanna’s paper is the most complete
report yet published on the Eocene in the area immediately north of the San Diego Pliocene basin
and the reader is referred to it for details which need not be repeated here. The following table, taken
without change from Hanna’s report on the paleontology of the La Jolla Quadrangle, is an excellent
summary of his treatment of the stratigraphy:

Thickness
Pliocene, San Diego formation in feet
Unconformity
§ Massive conglomerate, boulders well rounded, largely porphyritic vol-
c- ;
3 & | Poway con- canics; coarse; cross-bedded yellow and brown sands; some fine
& £ ] glomerate shaly sands with partings well developed due to mica; upper part
ie contains considerable soft white caliche.....0.0.0.0.000.0200.cceeeseeeeeeee 1000

Unconformity, at least in part.

g Light gray mudstone, slightly laminated in places; gray and yellow

3 & | Rose Cafion sandy shale; yellow and brown sands; in upper part lenses of con-
‘& shale glomerate, boulders well rounded, largely porphyritic volcanics,
E but some of the underlying mudstones and sands..............-.--...-.---- 300
3
A + d Massive, white, coarse-grained, cross-bedded sand, arkosic and some-
aia times carrying much muscovite and biotite.................0:sscesessseseeeeeees 20-200
Sires sand Greenish, gray, purple, red sands and sandy shale; some thin beds

composed almost wholly of Ostrea idriaensis Gabb.............2....000.- 100

Unconformity
Cretaceous, Chico formation

Neither the Delmar sand nor the Torrey sand appear to be exposed in the San Diego Pliocene
basin southeast of Mission or False Bay, but they are well exposed in parts of the La Jolla Quadrangle
to the north. The base of the Delmar sand is nowhere exposed in the area studied by Hanna though
it is possible it may be exposed farther north and its equivalent may outcrop along the shore just north

138°2A[mmonites]. Cooperii, n.s.” Gabb, Geol. Surv. Calif., Palaeo., Vol. 1, p. 69, pl. 14, figs. 23, 23a, 1864. This
species is referable to some genus with ornamentation similar to that of Anisoceras Pictet.

139 Wadleigh’s Map of the City of San Diego, San Diego County, Calif. C. B. Wadleigh, Publisher, 913 Fifth Street.
Scale 4 inches to the mile. Copyrighted 1888. Lith. by Los Angeles Lith. Co., 48 and 52 Banning Street, Los Angeles, Calif.
This map was called to our attention by Mr. John Davidson, Curator of the Junipero Serra Museum, San Diego Historical Society.

140 Hanna, M. A., “Geology of the La Jolla Quadrangle, California,” Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 16, no. 7,
pp. 187-246, pls. 17-23, 1 map, Nov. 20, 1926. See especially pp. 189-191. The paleontology of the Eocene of this quadrangle
by the same author is entitled “An Eocene Invertebrate Fauna from the La Jolla Quadrangle, California,” and is no. 8 in the same
bulletin, pp. 247-398, pls. 24-57, March 25, 1927. — See also, Cushman, J. A., and Hanna, M., “Foraminifera from the Eocene
near San Diego, California,” Trans. San Diego Soc. Nat. Hist., Vol. 5, no. 4, pp. 45-64, pls. 4-6, March 15, 1927. — See also,
Hertlein, L. G., and Grant, tv, U. S., Calif. Journ. Mines and Geol., Vol. 35, no. 1, 35th Rept. Calif. State Mineralogist, pp. 65-68,
Jan., 1939 [received at library of the California Academy of Sciences, Aug. 23, 1939].

VotuMmE IT] MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 41

of the Pacific Beach Pliocene section where it overlies the Cretaceous. As pointed out by Hanna,'*!
this lowest member of the La Jolla formation was apparently deposited in a shallow brackish water
embayment. The most common species, Ostrea idriaensis Gabb, Potamides carbonicola Cooper and
Unio (?) torreyensis M. A. Hanna, together with mud-flat sediments alternating with cross-bedded
and rapidly lensing layers, are features confirming Hanna’s opinion. The peculiar greenish hue of
much of the Delmar is also similar to certain other known brackish water deposits. This brackish
water facies is most prominent towards the top of the Delmar where layers of fossil leaves are occasion-
ally found. In the lower part of the formation as exposed, particularly along the beach at the foot
of Torrey Pines Grade, the sediments have a more normal marine facies. It is in these more normal
marine lower beds that most of the 32 species listed by Hanna occur. According to Hanna, “With
the exception of four species, all of the 32 species determined from the Delmar sand were present in
the Rose Cafion shale. These four species were not found to be abundant in the Delmar sand.
Because of these data it is believed the Delmar sand and the Rose Cafion shale constitute a unit
faunally, although a difference in salinity of the water and possibly a period of elevation separated the
deposition of the two, as is shown by the Torrey sand.” The preservation of the Delmar fossils is on the
whole very poor and the total fauna is no doubt much larger than the 32 species determined by Hanna.
Recent detailed studies of the Eocene, chiefly by Mr. Frank B. Tolman and by Professor B. L. Clark and
his students, have shown that it is possible to recognize a larger number of faunal horizons than was
known at the time Hanna’s paper was published, and on the basis of these recent data, the Delmar
would be differentiated faunally from the Rose Canyon shale faunas.

When in superposition the Torrey sand is in gradational contact with the underlying Delmar.
However, in at least one place, the Torrey sand is seen to rest with marked unconformity on the Black
Mountain volcanics, indicating an overlap of the Delmar by the Torrey to the east. It is well exposed
sometimes in castellated erosional'*? remnants high up on the hillsides in the general vicinity of the
mouth of Soledad Canyon south of Del Mar.

While not explicitly stated by Marcus Hanna, the Torrey sand, from its coarse-grained, cross-
bedded, and sometimes reddish colored character, together with the almost total absence of marine
fossils, has generally been considered non-marine. That this is at least in part not the case is shown
by the presence of limonitized outlines of marine pelecypod casts in exposures back of the beach at
the foot of Torrey Pines Grade. Also, a marine shale stratum in the middle of the Torrey sand has
been exposed by recent excavating along the new Torrey Pines Grade. It is probable that the Torrey
sand indicates a succession of geomorphic events in the crystalline area to the east somewhat similar
to that indicated by the quartz sand zone of the Ione formation in the foothills of the Sierra Nevada
in eastern central California. In the latter case an uplift of the peneplained Sierras was responsible
for the deposition in the coastal lowlands of glass sand, coal and pottery clay with anauxite between
Capay and Domengine times. This was pointed out in a paper presented by Mr. F. B. Tolman.'®
From Mr. Tolman’s interpretations it follows that the Delmar may correspond in age to some part
of the Capay formation and the Torrey sand to Ione or early Domengine time.

In much of the La Jolla Quadrangle the Rose Canyon shale lies conformably on the Torrey sand.
Where the Torrey sand is absent the Rose Canyon rests unconformably on the Black Mountain
volcanics or on the Cretaceous. Southward the Rose Canyon shale also appears to overlap the Torrey
sand. While there is an undoubted unconformity between the La Jolla formation and the Cretaceous,
the evidence seems to be indirect except where the Rose Canyon shale member rests nonconformably
on the Cretaceous.

The Rose Canyon shale occurs under much of the Kearny or Linda Vista Mesa and also farther
south where it underlies the San Diego Pliocene along the south side of Mission Valley. Most of
the peninsula of Point Loma consists of Eocene overlying the Cretaceous, but the beds are not very
fossiliferous in that area. A few fossils have been collected at the northeastern end of the peninsula,

141 Hanna, M. A., Univ. Calif. Publ. Bull., Dept. Geol. Sci., Vol. 16, no. 8, p. 257, 1927.

142 Holder, C. F., “Pyramids of Del Mar—Erosion of the Pacific Coast,’ Sci. American, Vol. 85, p. 8, 3 figs., 1901.
[Discusses badland effect of erosion at several localities along the Pacific coast}.

143 Amer. Assoc. Petrol. Geol., 22nd Ann. Meeting, Los Angeles, Calif., March 17-19, 1937. Program, pp. 61-62.

42 San Dieco Society oF Natura History [Memotrs

which suggests the presence there of the Rose Canyon member of the La Jolla formation. As mentioned
later in this paper the Rose Canyon fauna has been recognized in well samples from the region south
of San Diego Bay, suggesting that the Rose Canyon shale may be widespread underlying the San
Diego formation.

For a more complete list of the species occurring in the Rose Canyon shale the reader is referred
to the paleontologic report of Marcus Hanna already mentioned. The following is a very abbreviated
list of species reported by Hanna or discovered later by Tolman in the Rose Canyon member of the
La Jolla Quadrangle: Acila decisa Conrad, “Crassatellites” semidentata Cooper, Glycymeris rosecan-
yonensis M. Hanna, Macoma rosea M. Hanna, Nuculana parkei Anderson and Hanna, Calyptraea
diegoana Conrad, Ectinochilus problematica M. Hanna, Ectinochilus canalifer supraplicatus Gabb,
Pelecyora aequilateralis Gabb, “Surcula’” lindavistaensis M. Hanna, “Surcula” praeattenuata Gabb,
Turritella applini M. Hanna, Turritella scrippsensis M. Hanna, Turritella soledadensis M. Hanna,
Aturia myrli M. Hanna, Eutrephoceras hannai Vokes, “Flabellum” sandiegoensis M. Hanna. In
addition to these megafossils Mr. F. B. Tolman has collected Discocyclina cloptoni Vaughan, and
Dr. H. G. Schenck has reported Discocyclina clarki Cushman in the Rose Canyon shale.'**

The Poway conglomerate, which overlies the La Jolla formation, consists chiefly of conglomerates
with occasional lenses of cross-bedded sand. Gray shale lenses containing fossils occur in the lower
three hundred feet and considerable soft white chalky caliche is present in the upper part. According
to Hanna the Poway is in places conformable with the Rose Canyon shale but in other places an
erosional unconformity can be seen. Eastward it rests with marked unconformity on the Black Mountain
volcanics. Well records indicate that the Poway reaches a thickness of at least 875 feet.

A few fossils have been found in interbedded marine sediments in the Poway conglomerate.
Marcus Hanna reported the following species: Acila lajollaensis M. A. Hanna, Brachidontes ornatus
Gabb, Crassatellites mulates M. A. Hanna, Nuculana parkei Anderson and Hanna, Pholadomya
murrayensis M. A. Hanna, Pteria cf. pellucida Gabb, Tellina tehachapi Anderson and Hanna, Calyp-
traea excentrica Gabb, Discohelix murrayensis M. A. Hanna, Ficopsis remondii Gabb, Ficus mammillatus
Gabb, Turritella applini M. A. Hanna, Pseudoliva volutaeformis Gabb. In addition to those given
by M. A. Hanna, Dusenbury’” has cited the following six species from the Poway: Cardium brewerii
Gabb, Ostrea idriaensis Gabb, Pitar uvasanus Conrad, Solen novacularis Anderson and Hanna, Conus
remondii Gabb, Ectinochilus canalifer Gabb. Dusenbury (p. 91), also gave a short list of foraminifera
obtained from these beds.

Many years ago Fairbanks called what is now considered a part of the Poway conglomerate
an ancient river gravel and traced high elevation gravels which he believed were extensions of it far
to the east in the mountains of San Diego County. Much later Ellis and Lee included the Poway in
the lower part of the San Diego formation. Hanna, however, found diagnostic Eocene fossils in
shaly parts of the Poway, and during the winter of 1931 Mr. L. M. Huey of the staff of the San Diego
Society of Natural History collected a small fauna from a freshly opened cut of the Fenton Materials
Company’s quarry in Murray Canyon on the north side of Mission Valley. Huey’s locality, which
has been visited by many collectors since, is near one of Marcus Hanna’s original localities and in
about the same part of the section stratigraphically. The Eocene age of at least the lower part of
the Poway is now well established.

Within the last few years a number of specimens of fossil vertebrates have been collected from
the Poway conglomerate north of La Mesa. These appear to indicate an upper Eocene age for this
part of the Poway. Professor Chester Stock of the California Institute of Technology has studied
these specimens and has prepared for us the following statement in regard to them:

“The small collection of specimens obtained by the San Diego Society of Natural History in an excavation
for a cesspool north of La Mesa included several jaws and teeth of mammals definitely older than those known
from the Tertiary of California. Among the forms recognized are a carnivore, presumably a creodont, an agrio-

144 Another orbitoidal foraminifer resembling (if not identical with) Discocyclina psila Woodring occurs in the Rose Canyon
shale above D. clarki and ranges up into the D. cloptoni zone.

145 Dusenbury, Jr., A. N., “A Faunule from the Poway Conglomerate, upper Middle Eocene of San Diego County
California,” Micropaleontology Bull., Vol. 3, no. 3, pp. 84-95, 2 figs. [No. 2 unnumbered], June 15, 1932. (Published by
advanced students of Micropaleontology at Stanford University, Calif. Printed by Edwards Bros., Inc., Ann Arbor, Michigan).

VotumE II] Marine PLIOCENE OF SAN DIEGO, CALIFORNIA 43

choerid, and a tiny insectivore. Unfortunately the carnivore specimen is too imperfectly preserved to permit
definite identification as to genus and species. The agriochoerid and the insectivore resemble comparable types in
the Sespe upper Eocene of Ventura County. Since this collection was made, a few additional specimens have been
obtained from the Poway in the vicinity of San Diego, the most important of which is a titanothere. The latter,
determined on the basis of a skull fragment with teeth, is tentatively referred to the upper Eocene genus Metarhinus.
A survey of the fossil mammals from the Poway suggests an upper Eocene age and a faunal stage earlier in time
than that recorded from the upper Eocene of the Sespe.”

Much of the Poway contains no fossils and appears to be of continental rather than marine origin
and in this respect recalls the Sespe formation of the Ventura basin and other regions to the north.

The Ballena placer workings'*® for the recovery of gold east of Ramona in parts of sections 17,
18, 19, 20 and 21 of T. 13 S., R. 2 E.,, S. B. B. and M., are operated in gravels referred to the
Poway conglomerate by Donnelly.'*7 Although Donnelly stated that these gravels were marine, we
agree with Fairbanks’ conclusion that they represent a fluviatile deposit.

Although the Eocene is not known in surface exposures in the San Diego Quadrangle south and
southeast of Balboa Park, some of the wells drilled in the south bay region have penetrated Eocene
strata. Through the kind cooperation of Mr. J. E. Pettijohn, we have had access to the geological
reports of George H. Doane on the San Diego Gas and Petroleum Corporation’s Holderness No. 1
Well in the southeast quarter of section 32, Township 18 S., Range 2 West, San Bernardino Base
and Meridian, near the mouth of the Tia Juana River. This well penetrated over a thousand feet of
Eocene shales, sandstones and conglomerates, some of which contained diagnostic Eocene fossils.'**
According to Mr. Doane, Discocyclina clarki Cushman was found in the cores from 2,946-2,959 feet
and 3,286-3,289 feet. In cores from 3,195-3,289 feet Eosolen novacularis Anderson and Hanna was
obtained and Cyclinella bunkeri M. Hanna occurred between 3,286 and 3,289 feet. Between 3,289
and 3,324 feet the following were identified: “Flabellum” sandiegoensis M. Hanna, “Tellina”’ cf.
scrippsensis M. Hanna (young), “Cardium” sorrentoensis M. Hanna, Corbula cliffensis M. Hanna,
Turritella applini M. Hanna, Acila decisa Conrad and “Cardita” sandiegoensis M. Hanna. These
fossils indicate the presence of the Rose Canyon member of the La Jolla formation. In three horizons
between 4,498 and 4,795 feet Baculites chicoensis Trask was identified. This species is characteristic
of the Cretaceous. Dr. G. D. Hanna and C. C. Church have furnished us a report on a core of this
well from a depth of 3,706 feet as follows: “Gray, sandy, micaceous shale with abundant carbonized
plant remains, shell impressions and foraminifera: Cibicides sp., Eponides mexicana Cushman, Robulus
inornatus d’Orbigny, Robulus mexicanus var. nudicostatus Cushman & Hanna, Siphonina cf. jackson-
ensis Cushman & Applin. Eocene. Domengine.” It is likely that the Eocene is widespread below the
San Diego formation in the region south of the San Diego River Valley but is overlapped by the
Pliocene eastward.

From time to time attempts have been made to obtain coal in the San Diego region. It is now
impossible to locate accurately these reported carbonaceous deposits, but some of the coal beds have
been reported in localities where Eocene strata are exposed at the surface. Tyson,’ in 1850, stated:
“Tt had been reiterated over and over again in letters, newspapers, and in other ways, that there was,
a few miles north of this port, near the seashore, a coal formation capable of furnishing ample supplies
of the ‘best of coal for steamers’ and other purposes. These beds prove to be layers of bitumen an
inch or two thick, alternating with thin strata of small gravel and sand.” Many years ago the San
Diego Herald,!” published in San Diego, stated (1856) that coal was found on Lewis Rose’s ranch

about five miles from town. According to this paper, prospectors on Rose’s ranch dug to a depth of

146 Fairbanks, H. W., Calif. State Mining Bureau, 11th Ann. Rept. State Mineralogist, Vol. 11, p. 91, 1893. — Merrill,
F. J. H., Calif. State Min. Bureau, 14th Ann. Rept. State Mineralogist, p. 652, 1916. Issued as a separate Dec., 1914.

147 Donnelly, M., Calif. Journ. Mines and Geol., Calif. State Mining Bureau, 30th Rept. State Mineralogist, Vol. 30,
no. 4, p. 369, Oct., 1934.

148 The column, as constructed by George H. Doane from a study of the cores and ditch samples, is included in the present
report under the treatment of the San Diego formation.

149 Tyson, P. T., “Geology and Industrial Resources of California,” Senate Ex. Doc. 47, 31st Congress, Ist Session, 1850
(reprinted with an introduction, published by Wm. Minifie and Co., Baltimore, 1851), p. 20.

150 The San Diego Herald, Vol. 6, June 28, 1856, p. 2, col. 1.

44 San Dreco Society oF Naturat History {[Memotrs

120 feet. Later The Daily World,'’’ also published at San Diego, contained a notice (1872) of a
meeting of the owners of the “Soledad Coal Mines.” These mines are said to have been located in
Rose Canyon. The type locality of the Rose Canyon shale of Eocene age is at the bend of Rose
Canyon. Old records indicate that a coal mine once existed a few miles farther north somewhere
near the present location of the town of Del Mar. This is shown on a manuscript map'” drawn in
1850 by Lieutenant Cave Johnson Couts of the First Dragoons, U. S. Army.

The lignitic Delmar member of the La Jolla formation exposed at the base of the beach bluff
at Torrey Pines on the south side of the mouth of Soledad Canyon was briefly described in 1857 by
William H. Emory, then Major, First Cavalry, and United States Boundary Commissioner.'”? Probably
the Del Mar coal mine was an attempt to obtain coal of commercial value from this Delmar member
of the La Jolla formation although we did not attempt to locate the exact position of this mine.'”*
Merrill’”’ discussed the occurrence of coal near Del Mar in his report on the mineral resources of
San Diego County. Eocene rocks are exposed in this area, as shown on the map by Marcus Hanna.
The coal reported in a boring at La Jolla occurred in Cretaceous rocks, according to Fairbanks.'*°

Inasmuch as some of the Eocene sandstones are similar in general field appearance to some facies
of the Pliocene sands, we include here a sedimentary analysis of an Eocene sample for comparison.

This analysis has been made for us by Dr. Gordon A. Macdonald.

No. 14. Eocene lithologic sample: north side of gully just north of Mercy Hospital on 6th
Avenue Grade to Mission Valley. Ten feet below conglomerate. L. G. Hertlein and U. S. Grant, rv,
collectors. August 12, 1937.

LIGHT MINERALS:

(ORT of ee arr reser try Seba eet a ern eee 54.9%
Orthoclase ............--.-. Forth ee aN Sn aR EEE 25.0%
Oligoclases zi ee S ae Pen acttsccctesinesetw lan 15.0%
Al Bite ee ite ore ee See SE a A 4.0%
FETFIA VY gu ROADS ne eotere tee ere ce rg eee shee aon occa Ss IGG

Magnetite—very rare
Ilmenite—moderately abundant
Epidote—abundant
Zoisite—abundant

Pink garnet—rather rare
Titanite—rather rare
Andalusite—rare

Zircon—rare
Piedmontite—rather rare

“The grains vary from .05 to ca. .4 mm. in diameter, and average ca. .2 mm. They are largely angular,
but some are subangular. The sorting is rather good. The orthoclase feldspar is considerably kaolinized.
“This Eocene sample is very unusual, in that the heavy fraction is made up very largely of epidote and

151The Daily World, Vol. 1, no. 73, Oct. 16, 1872 [on unnumbered p. 3]. This reference was called to our attention by
Mr. John Davidson, Curator of the Junipero Serra Museum of the San Diego Historical Society.

152 This map was shown to us by Mr. Cave J. Couts of the Guajome Rancho, near Oceanside, San Diego County, son of
the author of the map. A reproduction of this map was included by Fr. Zephyrin Engelhardt in his work “The Missions and
Missionaries of California,’ New Series, Local history, San Luis Rey Mission, (San Francisco, California, 1921), p. 257.

153 Rept. United States and Mexican Boundary Surv., Vol. 1, pt. 2, p. 90, and text figure on p. 85, 1857. Emory stated
that the lignite was not of economic importance.

154 Most if not all of the reports of the occurrence of “coal” in the San Diego region are based upon the existence of
bituminous beds in the Eocene or the Cretaceous. Many years ago Goodyear reported “‘coal’ ’and “slate rock with some coal” at,
respectively, 177 feet and 245 feet depths in a well which had been sunk for the purpose of securing artesian water “‘on the east side
of the bay, at a point where the mouth of the well was ninety-four and one-half feet above high water.” From the text Goodyear
appears to refer to San Diego Bay. If this is correct the well must have been in the Pliocene or in a deposit of later age. If he had
been referring to Mission Bay instead of San Diego Bay the well could have been in the Eocene. See Goodyear, W. A., Calif.
State Mining Bureau, 8th Ann. Rept. State Mineralogist, p. 518, 1888.

155 Merrill, F. J. H., Calif. State Mining Bureau, 14th Rept. State Mineralogist, p. 713, July, 1915 (1916). Also issued as a
separate, “Geology and Mineral Resources of San Diego and Imperial Counties,” Dec., 1914, p. 83. “Lignite seams of limited
thickness and extent have been reported from borings in the vicinity of San Diego, and tradition says that some thirty years ago
a bed of coal exposed at low-water mark, in the beach near Del Mar, was worked as a source of fuel for blacksmith forges.”

156 Fairbanks, H. W., Calif. Stare Mining Bureau, 11th Ann. Rept. State Mineralogist, Vol. 11, p. 96, 1893.

VotumE II) MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA 45

zoisite, with a little of the rare mineral piedmontite. The fact that the only minerals left in the heavy fraction
are of types which are resistant to chemical decomposition suggests that the Eocene may have been a time of
pronounced chemical weathering. This of course corresponds well with the known character of the Ione and
Capay sands. However, it is risky to attempt any conclusions on the basis of a single sample. The fact that the
feldspar is still recognizable in this sample, although somewhat kaolinized, suggests that conditions were less
severe than in the case of the Ione, or, which would bring about the same result, that erosion was more rapid
in the San Diego region than in the source areas of the Ione.” (G. A. Macdonald).

At several localities in the coastal region between Rose Canyon and Carlsbad, Eocene shales and
clays are of suitable quality for the manufacture of brick, tile and pottery. For many years brick has
been manufactured in Rose Canyon. At the present time the Union Brick Company operates on about
100 acres in this canyon. The Vitrified Products Corporation of Old Town controls clay properties
five miles northeast of Cardiff and also two miles north of Linda Vista. The Pacific Clay Products
Company of Los Angeles controls about thirty-five acres on the Agua Hedionda Land Grant near
Carlsbad. All of these properties are benefited by good transportation facilities afforded by the Santa Fe
Railroad and the paved highways.

ABSENCE OF OLIGOCENE AND MIOCENE ROCKS
IN THE SAN DIEGO REGION

Oligocene sediments are absent in the San Diego region so far as now known. There are no
sediments present between the Eocene and Pliocene at any of the known localities in that area and
no Oligocene fauna has been reported in the extreme southern part of the State.

Miocene sediments are likewise absent in the area under discussion. In 1909 Tempére and Pera-
gallo!” listed 75 species of diatoms from “San Diego-Californie (Etats-Unis) Dépét fossile marin.”
A careful examination of this list shows that the material undoubtedly came from some California
locality of upper Miocene (Monterey) age. It was probably transmitted to Paris by some microscopist
to whom the beauty of the fossils was appealing and the need of exact locality data was not apparent.
The material may have come from any one of a great many known exposures, but probably was
obtained somewhere in the vicinity of Capistrano where beds of the same age do outcrop. Many years
ago C. R. Orcutt'”® reported “a specimen of diatomaceous earth from the ocean beach near San Diego.”
It was stated that this specimen was “very like some samples of the Redondo Beach deposit, and may
have been washed from there.” Orcutt’s specimen undoubtedly came from a source nearer than
Redondo, perhaps from the vicinity of Capistrano. North of Capistrano, beds of Vaqueros age con-
taining the Turritella inezana fauna have been reported by Woodford.’ Beds of Temblor age also
occur in the north but they are likewise lacking in the area under discussion.

Blake and Conrad appear to be responsible for an early report of the presence of Miocene strata
in the San Diego region. In Volume 5 of the U. S. Pacific Railway Reports, Blake stated:'®° “Before
leaving the Mission of San Diego, a block of sandstone, filled with fossils, was handed to me, but
the locality was not seen. It is a compact sandstone, not unlike that of the Bay of San Francisco
and Oregon. Mr. Conrad finds it to contain the following species: Cardium modestum, Nucula decisa,
Corbula Diegoana, Mactra Diegoana, Natica Diegoana, Trochita Diegoana, Tellina Diegoana, and
T. congesta. He also remarks a palaeontological relation between these fossils and those of Monterey,
Carmello, and those found in boulders in Oregon by Mr. Townsend and Professor Dana.” These
species were described by Conrad in an Appendix of the same volume’®' under the heading: “Fossils

157 Tempére, J., and Peragallo, H., “Diatomées du Monde Entier,” Ed. 2, pp. 160-161, 1907-1915. [These pages issued in
1909]. See also edition 1 (Paris), 1889-1895, pp. 271-272. Dr. G. D. Hanna kindly called these references to the attention of
the authors. See Hanna, G. D., Bull. de la Soc. Franc. de Microscopie, Vol. 5, no. 3, p. 110, 1936.

158 Orcutt, C. R., West Amer. Sci., Vol. 7, whole no. 57, p. 136, Feb., 1891.
159 Woodford, A. O., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 15, no. 7, pp. 178-180, 1925.

160 Blake, W. P., U. S. Senate Ex. Doc. 78, and House of Representatives, Ex. Doc. 91, 33rd Congress, 2nd Session,
“Reports of Explorations and Surveys to Ascertain the Most Practicable and Economical Route for a Railroad from the Mississippi
River to the Pacific Ocean,” etc., Vol. 5, pt. 2, Geological Rept., chap. 13, p. 176, 1857.

161 See pages 322-327. These species were actually first described without figures in House Doc. 129, Projected Vol. 3,
33rd Congress, Ist Session, 1855, Ap. to Report of W. P. Blake, pp. 11-18.

46 San Disco Society oF Naturat History [Memorrs

of the Miocene and Recent Formations of California.” These species are now known to be Eocene
fossils with the exception of “Tellina” congesta, the type of which is said to have come from the
Miocene Monterey shale near Monterey, California.'®

Ellis? mentioned some fossils collected in south Las Choyas Valley which Dall determined as
“upper Miocene or probably Pliocene.” Other fossils collected about 31/, miles east of Chula Vista
in a canyon locally known as Fossil Canyon, were determined by Dall to be of upper Miocene age,
according to Ellis (p. 63). This latter locality is a well known Pliocene fossil bed from which the
present authors have collected a small but distinctly Pliocene fauna.

Merrill'®* in 1914 pointed out that beds of middle Miocene age, which are the chief source rocks
of oil in the San Joaquin Valley and Orange County, California, are lacking in San Diego County
and that the deepest wells drilled have passed through the Tertiary and Cretaceous strata and penetrated
a black shale, sometimes calcareous, which he suggested was probably of Jurassic age, although no
faunal evidence for that age is known. Asphalt reported along the coast was considered to have come
from long distances and not from the region about San Diego. Merrill’s report indicated that there
is but little chance for petroleum to be found in San Diego County and pointed out that drilling, while
laudable as evincing a cordial public spirit, should only be undertaken by people or companies able
to stand a loss, due to the fact that the possibility of finding oil in commercial quantities is slight.
The present authors are inclined to agree with Merrill’s conclusion.

The logs of a number of wells which have been dug or drilled in the San Diego region have
been given by Ellis'®’ in his report on the water resources of western San Diego County, and by the
present authors in a recent paper.’*° Some of these well logs are mentioned briefly in the present
paper in the discussion of the Cretaceous and of the Pliocene.

PLIOCENE
In 1874 W. H. Dall’® listed and discussed the fossil mollusks collected by Henry Hemphill

from the material removed in digging a well for water in San Diego. The well was located near the
mouth of what is now known as Cabrillo Canyon in Balboa Park. Although this well has long since
been filled in, the brick lining of the mouth of the well can still be seen at the date of this writing
(October, 1939) in a grassy swale near two eucalyptus trees. It is located “on the northerly prolongation
of the east line of Eleventh Avenue, 85 feet north from the easterly production of the north line of
Beech Street.”’®* The elevation of the ground at the well-head is approximately 96 feet above mean
sea level and as the well was stated to have attained a depth of 160 feet, the bottom was considerably
below sea level. The mouth of the well is brick-lined and has a diameter of about 102 feet. The location
of the well is shown on the contour map (text figure la) and the sequence of some of the fossil beds
penetrated by the well are shown in the accompanying cross section (text figure 1b). Although the
strata encountered in the well were said to be fossiliferous throughout, the lower beds, from which
Dall stated most of his specimens came, were not discovered by us outcropping in the immediate environs
of the well. The large scale one-foot contour interval map of Balboa Park in the City Engineer’s Office
and a recent Transit survey determine the dip of the beds in the vicinity of the well to be 4°, in a
direction south 33° 30’ west. If the dip and strike of the beds remain constant, the fossiliferous strata
at the bottom of the well might be expected to outcrop in the bottom of Cabrillo Canyon between Juniper
and Laurel Streets projected.

Dall concluded that the age of the fossils obtained from the well was Pliocene. This was the

162 Schuchert, Charles, assisted by Dall, W. H., Stanton, T. W., and Bassler, R. S., U. S. Nat. Mus., Bull. 53, Pr. 1,
p. 643, 1905. According to Dall (U. S. Geol. Surv., Prof. Paper 59, p. 126, 1909) this species appears to be a Macoma. The
San Diego Eocene species to which the name congesta was erroneously applied by Conrad, is not known to the present authors.

163 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, p. 62, 1919.

164 Merrill, F. J. H., Calif. State Mining Bureau, Bull. 69, pp. 467-468, 1916. Issued as a separate Dec., 1914.

165 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv. Water Supply Paper 446, pp. 55-68, 1919.

166 Hertlein, L. G., and Grant, 1v, U. S., Calif. Journ. Mines and Geol., Vol. 35, no. 1, 35th Rept. Calif. State Mineralogist,
pp. 74-77, Jan., 1939, [received at library of the California Academy of Sciences Aug. 23, 1939).

167 Dall, W. H., Proc. Calif. Acad. Sci., Vol. 5, pp. 296-299, 1874.

168 Data from H. W. Jorgensen, City Engineer of San Diego, letter of April 7, 1939.

47

MarINE PLIOCENE OF SAN D1kGO, CALIFORNIA

VoLuME II]

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48

San Dieco Society oF Naturat History [Memoirs

first faunal assemblage of any size in California to be definitely placed in the Pliocene, and hence
that locality is one of the early well-defined Pliocene localities of the State. As Dall’s early paper is
now becoming quite rare, we reproduce below the list of fossils exactly as given by Dall together with
what we consider are the proper names of the species represented, in modern nomenclature, in the
column at the right.

P. 296
ao!
ped
os
“ 4.
5,
“6

“Ee

Exact Copy or OriGinat List

Glottidia albida, Dall ex Hinds.”
Xylotrya, sp. indet. Tube only.”
Cryptomya Californica, Contr.”
Solen rosaceus, Cpr.”

Solecurtus Californianus, Conr.”
Macoma (var.?) expansa, Cpr.”

. Callista, sp. indet. Smooth, inflated, thin; much

like Callista Newcombiana, erroneously de-

scribed as Lioconcha by Gabb.”

. Cardium centifilosum, Cpr.”
. Venericardia borealis, Conr.”
. Lucina nuttallii, Conr.”

. Lucina borealis, Linn.”

. Lucina tenuisculpta, Cpr.”

. Cryptodon flexuosus, Mont.”
. Modiola recta, Conr.”

. Arca microdonta, Conr.”

. Nucula, sp. n. according to Dr. Cooper; named

in MSS. by Carpenter. Looks much like N.

tenuis.”

. Acila Lyallii, Baird. This species has been fre-

quently reported as castrensis, Hds.”

. Leda coelata, Hinds.”

. Pecten hastatus, Sby.”

. Amusium caurinum, Gld.”

. Janira florida, Hds.”

. Ostrea conchaphila, Cpr.”

. Placunanomia macroschisma, Desh.”

. Tornatina eximia, Baird.”

. Cylichna cylindracea, Linn.”

. Dentalium hexagonum, Sby.”

. Dentalium semipolitum, B. and S.”

. Siphonodentalium pusillum(?), Gabb.”
. Calliostoma annulatum, Mart.”

. Galerus filosus, Gabb, as Trochita.”

. Crepidula navicelloides, Nutt.”

. Crepidula princeps, Conr. This is not grandis

of Midd.”

. Turritella Jewettii, Cpr.”
. Bittium asperum, Cpr.”

Myurella simplex, Cpr.”

“36-39. Drillia, sp. indet. This and three other

“41.

forms of Drillia so closely resemble Gulf
forms, that it is inadvisable to describe them
without a comparison of specimens.”

Surcula Carpenteriana, Gabb, and variety Try-
oniana, can hardly be separated as species. The
transition is very gradual and complete.”
Mangelia variegata, Cpr.”

“42-45. Mangelia, spp. indet. The same remark ap-

plies here as to No. 36.”

PROBABLE EQUIVALENT IN MODERN
NoMENCLATURE

Glottidia albida Hinds

Xylotrya sp.

Cryptomya californica Conrad

Solen rosaceus Carpenter

Tagelus californianus Conrad

Tellina expansa Carpenter or Tellina (Oudaria)
buttoni Dall

?Compsomyax subdiaphana Carpenter

Nemocardium centifilosum Carpenter
Cardita (Cyclocardia) ventricosa Gould
Lucina (Lucinisca) nuttalli Conrad

Lucina (Lucinoma) annulata Reeve
Lucina (Parvilucina) tenuisculpta Carpenter
Thyasira gouldii Philippi

Volsella { = Modiolus} recta Conrad

Arca trilineata Conrad

Nucula exigua Sowerby

Acila castrensis Hinds

Nuculana taphria Dall

Pecten (Chlamys) hastatus Sowerby

Pecten (Patinopecten) healeyi Arnold
Pecten (Pecten) stearnsti Dall

Ostrea conchaphila Carpenter

Pododesmus macrochismus Deshayes
Acteocina eximia Baird

Cylichnella alba Brown

Dentalium neohexagonum Sharp and Pilsbry
Dentalium semipolitum Broderip and Sowerby
Cadulus fusiformis Pilsbry and Sharp
Calliostoma annulatum M

Calyptraea (Trochita) filosa Gabb
Crepidula nummaria Gould

Crepidula princeps Conrad

Turritella jewettii Carpenter

Bittium (Lirobittium) asperum Gabb
Terebra martini English

? Possibly Clathrodrillia, four new species

Megasurcula carpenteriana Gabb

Mangelia barbarensis I. S. Oldroyd
? Possibly Mangelia n. sp., and others

VoLuME II]

Exact Copy or Oricinat List

“46. Clathurella Conradiana, Gabb. The specimens
are slightly stouter than Gabb’s figure, but vary
among themselves in this respect, and in other
characters are similar to his species.”

“47. Odostomia straminea, Cpr. var.”

“48. Odostomia, sp. indet. Very imperfect.”

“49. Chemnitzia torquata, Cpr.”

“50. Eulima rutila, Cpr.”

“51. Scalaria subcoronata, Cpr.”

“52-55. Cancellaria, 4 spp. indet. Most of them, as
far as memory serves, resemble southern forms
not at hand for comparison.”

“56. Neverita Recluziana, Petit.”

P. 298

“57. Sigaretus debilis, Gld.”
“58. Ranella Mathewsonii, Gabb.”

MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 49

PRoBaBLE EQUIVALENT IN MopERN
NoMENCLATURB

Glyphostoma conradiana Gabb

?Odostomia (Evalea) tenuisculpta Carpenter

Odostomia sp.

?Turbonilla (Strioturbonilla) torquata Carpenter

Melanella (Eulima) rutila Carpenter
or Strombiformis riversi Bartsch

Probably Epitonium (Nitidiscala) tinctum
Carpenter

Probably Cancellaria arnoldi Dall, C. hemphilli Dall,
C. crawfordiana Dall, and Cancellaria, n. sp.

Polinices (Neverita) reclusianus Deshayes

Sinum debile Gould

Gyrineum lewisii Carson

“59. Olivella boetica, Cpr.”

“60. Nassa fossata, Gld.”

“61. Nassa mendica, Gld.”

“62. Astyris tuberosa, Cpr.”

“63. Astyris, sp. indet. jun.”

“64. Ocinebra lurida, Cpr.”

“65. Pteronotus festivus, Hinds.”

“66. Trophon orpheus, Gld.”

“67. Fusus (Colus) Dupetit-Thouarsi ? Kien.”

“68. Chrysodomus, n. s. Too imperfect for descrip-
tion, but very distinct; perhaps a Volutopsis,
as the nucleus would indicate.”

“69. Chrysodomus Diegoénsis, n. s.”

Olivella pedroana Conrad

Nassarius (Schizopyga) fossatus Gould
Nassarius (Schizopyga) mendicus Gould
Mitrella tuberosa Carpenter

Mitrella sp. or Cosmioconcha n. sp.
Ocenebra lurida Middendorff

Triremis festiva Hinds

Trophon (Boreotrophon) stuarti E. A. Smith

Fusinus (Barbarofusus) ?barbarensis Trask

Searlesia diegoénsis Dall

Dall'® later referred to the sediments from which the San Diego well fossils were obtained as
the “San Diego Beds” and Arnold'”® referred to these fossiliferous sands as the “San Diego formation.”
Although Arnold'’! described in much greater detail the Pliocene sandstones of Pacific Beach and
listed a considerable fauna from them, the San Diego well must be considered the type locality of the
San Diego formation. This is unfortunate, since the historic well has long since been filled in and
an outcrop of beds with an identical fauna has not yet been definitely located in the immediate
environs. Due to the fact that the San Diego formation cannot readily be divided into members
which can be recognized at different localities, it is entirely reasonable to include in the San Diego
formation all the marine Pliocene sedimentary beds of the region, with the exception of the overlying
reddish-brown conglomeratic sandstone which caps most of the mesas and which may be of late
Pliocene or Pleistocene age.

The Pliocene exposed in the beach bluffs at Pacific Beach, however, may represent a higher part
of the Pliocene than the Trophosycon beds exposed in the road cut below the Mercy Hospital and
the Pliocene fine sands exposed along India Street. The Pacific Beach beds are not continuous in
surface exposures with the Pliocene in the San Diego Mesa and with just what part of the latter
the Pacific Beach beds correlate cannot be stated definitely now. Some of the older forms found in
the mesa Pliocene, such as Trophosycon, have not yet been discovered at Pacific Beach.

DISTRIBUTION

Pliocene beds here referred to the San Diego formation compose the greater part of the mesa-

169 Dall, W. H., U. S. Geol. Surv., 18th Ann. Rept., Pt. 2, 1898, opp. p. 334, p. 337.
170 Arnold, R., Journ. Geol., Vol. 10, p. 130, 1902. According to Arnold the San Diego well was 149 feet deep.
71 Arnold, R., Mem. Calif. Acad. Sci., Vol. 3, pp. 57-58, 1903. — U. S. Geol. Surv., Prof. Paper 47, p. 28, 1906.

50 San Dreco Society oF Naturat History [Memors

lands of the San Diego region, and cover a large area from the south slope of the San Diego River
Valley to some distance beyond the Mexican Boundary. They also outcrop on the lower southern
slopes of Mount Soledad and in the bluff behind the beach at Pacific Beach. No Pliocene is known
to occur in the Linda Vista Mesa north of the San Diego River Valley nor on Point Loma.

The contact between the known Pliocene sediments and the Eocene and older rocks is indicated
on the map (text figure 2). Over much of the region the Pliocene sandstones are covered by a mantle

Section AAU
Pawt

> Baacs\|

Yoo, TI6S.
Y V4}

Or MOUNT HELIX
ta} LG tty py

VAL

SXANN

Se
Cretaceous over/ain by \
Eocene with marrow .

Pleistocene terrace \We \
along shore \ a) y+
PT. poe Hs

Cretaceous exposed along shore

NNNAS

LEGEND

—___ Detinite Fault
— ~~ Probable Fau/t
on" Aypothetical Fault

Quaternary marine and non-marine tara S x27 At n S Z 4 ities
race deposits, valley Fill, efc. WHE SSS . L, Nx

FRAY “erine San Diege Pliocene. Generally : QI WAeescan NSS)

overlain by Sweitzer conglomerate Soult \ we
of Sun Diego River valley }

(TEA) Marine Eocene including Poway conglem- | i} COTAY MESA |

erate

t
Pre-Tartiary igneous and metamor- i Ste
Aten rocks prasimcaty Mesoxole “me? Serer SS SSAA Sb
. See c
+ —- —- — Boundary of Tawnship \ pokey Ds FAGALIESE RIE
—: —: — Boundary of Land Grant. R Ss = P= M
SCALE
lho 1 2 3 4 S Miles
| ess es ees |

Geology ty £6 Hertlain and US Grant, @ Base from San Diego County Map.

Text Fic. 2. Map of areal geology of the San Diego region, Quaternary sediments on the mesas and
on some of the higher terraces have been omitted. To have included them all would obscure the true
distribution of the older deposits. The small scale of this map has made it impracticable to attempt to
delineate the distribution of the upper Cretaceous rocks exposed in the sea-cliffs along the southern half
of Point Loma. Due to the scale, certain narrow Pleistocene terrace deposits which occur along the west
shore of Point Loma have also been omitted. The intermittent streams have been emphasized to bring out
the drainage direction and pattern. The mine symbol on the west side of Point Loma indicates the position
of the “Coal Mine” which is about 134 miles north of the lighthouse at the end of Point Loma. The topo-
graphy of this region is shown on U. S, Geological Survey Maps of the San Diego, La Jolla, Cuyamaca, and
E] Cajon quadrangles.

of later terrace material and soil which has not been indicated on the map. A great part of the mesa
south of the San Diego River Valley is capped by a characteristic reddish-brown conglomerate, which has
been named the Sweitzer formation. Due to the limited time which could be devoted to field work
and the small scale of the map, it has not been possible to plot the contact between the San Diego
formation and the overlying Sweitzer formation. All of the Coronado peninsula, including North
Island, the terrace upon which the business section of the City of San Diego has been built, the
Pacific Beach-Crown Point Terrace, and the lower terraces east of the southern part of the San Diego
Bay are of Pleistocene age as shown by numerous deposits of Pleistocene fossils.

VotumE II} Marine PLIOCENE OF SAN D1kGO, CALIFORNIA 51
LITHOLOGY AND SEDIMENTATION

Lithologically the San Diego formation consists of generally fine-grained sands of a bluish-grey to
yellowish-brown color, with occasional layers and lenses of gravel. Where the sand is very fine-grained
and of a light bluish-gray color, it is difficult to distinguish from some of the Eocene sandstones
exposed just to the north of the Pliocene basin. Fine-grained sands, often micaceous, compose the
bulk of the observed thickness of the San Diego formation, but locally it grades into coarser sand
and occasionally gravel and lenses or layers of conglomerates. In the mesa on the south side of Tia
Juana Valley, about one mile west of the Boundary School, a considerable thickness of conglomerates

EOCENE-PLIOCENE CONTACT PLIOCENE-PLEISTOCENE CONTACT
SECTION A-A‘

PLEISTOCENE SANOS

SWEITZER CONGLOMERATE

ke i) SANDSTONE SHOWING

OCCASIONAL INDURATED LAYERS 94 =

Sey N VALLEY ALLUVIUM PLEISTOCENE SEA ae
EOCENE SANDY SHALE

SECTION 8-8’

Text Fic, 3. Section A-A’. Generalized section of Pacific Beach Pliocene deposits as exposed in the
bluff facing the beach. Total distance north to south about 3,850 feet. Vertical scale greatly exaggerated
Pecten healeyi occurs most abundantly in the lower half of the beds exposed in this section. Beds in the
upper half of the section contain abundant specimens of Pecten bellus.

Section B-B’. Diagrammatic sketch showing the relationships of the Pliocene San Diego formation to
the Eocene, to the Sweitzer formation on Sixth Avenue, and to the Pleistocene. Section approximately
north and south from Mission Grade to foot of 26th Street. Distance about 5 miles. Vertical scale greatly
exaggerated.

The locations of the cross-sections are shown on the map in text figure 2.

and coarse indurated sands is exposed in a small steep canyon on the United States side of the Mexican
Boundary. This conglomerate stratum is fully 100 feet thick, and the larger boulders range up to
three feet in maximum diameter. The discovery of a Pliocene fossil locality not far to the west suggests
that this conglomerate is also Pliocene in age and the equivalent of the San Diego formation of Otay
Mesa and other Pliocene mesas farther north. The boulders are moderately well rounded and consist
of hard dense crystalline rocks of varying colors. The source of the boulders may have been
some of the nearby mountains just south of the Border in Lower California. Coarse-grained sand-
stones are uncommon in general in the San Diego formation but a prominent outcrop of very coarse-
grained gravelly sandstone occurs in a spur between the two northeastern extensions of Paradise Valley,
about three and a quarter miles west of Sweetwater Reservoir (Plate 10, figure 2).

The other lithologic extreme met with in the San Diego formation is represented by marly
material which occurs in pockets or seams, and rarely in beds of nearly pure white marl. Due to
the fact that much of the mesa region is mantled by soil which is effectively held in place, even on

52

San Dreco Society oF Naturat History

pecen

BAY POINT
FORMATION

QUATERNARY

SWEITZER
FORMATION

SAN DIEGO
FORMATION

POWAY
CONGLOMERATE

TERTIARY

ALLUVIUM Ri

ROSE CANYON
SHALE

TORREY SAND

MARINE
UPPER CRETACEOUS
AT
ILA JOLLA, PT. LOMA
ANDIN
VARIOUS WELLS

NON=MARINE
RETACEOUS PENE—
TRATED IN WELLS
PROBABLY
EQUIVALENT TO T
TRABUCO FORM.
OF THE
SANTA ANA MTS.

Ww
z
Ww
.)
°
Fe
2
@
w
4
i
vo
Q
WwW
a
ri
ro)
o
uw
”
3
Ww
18)
<
¥
VO

MESOZOIC

TRIASSIC OR JURASSIC

BLACK
MOUNTAIN
VOLCANICS

0-300’ Beach deposits, valley fill and terrace
deposits, gravel, sand and silt

1-30" Marine fossiliferous terrace deposits and
non-marine valley fill, gravel, sand and silt

5-30’ Conglomerate and conglomeratic sand-
stone, generally brown or reddish brown

1250’ Soft yellowish and gray sands, sometimes
micaceous or marly, often fossiliferous, with
minor amounts of conglomerate

875° Massive conglomerates with sand or clay
matrix With occasional coarse or fine brown
sand or gray sandy rarely fossiliferous shale

300’ Blue to gray sandy shale with thin
limey fossiliferous beds.

Coarse and fine-grained sandstones grad
into penacecde shales with occasional carbon—

1000-2000" Hard well stratified sandstones
sometimes concretionary and gray or black
shales. Fossiliferous.

250-1000" Hard reddish sandstones and con-
glomerates

2000” Basalt flows, agglomerates, sitered shale
and sandstone cut by later dikes and intruded
by acidic plutonic rock.

Text Fic, 4. Columnar section of the rocks exposed in the
southwestern part of San Diego County. This section, except
the Cretaceous part, is compiled from observations of surface

exposures of the rocks.

from well logs.

The Cretaceous section is compiled

[Memoirs

VotumE II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 53

the slopes, by brush and lichens, moss and small ferns, no estimate of the Proportion, nor idea of the
regularity in distribution of these chalky deposits could be obtained; but they appear to be more
common in the eastern parts of the mesas. These marly deposits are exposed at several places in the
eastern Otay region and on the edge of the mesa north of the upper reaches of Las Choyas Valley. It is
possible that the thicker beds represent quieter and slower deposition on the leeward sides of projecting
promontories of pre-Tertiary hard rock, some of which now form foothills in that district. The seams
and pockets may be due to a concentration of limy material by percolating waters.

A dark colored bentonite bed eight inches to one foot thick occurs in the Pliocene yellowish-brown
and gray sands exposed in a road cut on Federal Avenue about 400 feet east of 35th Street. During
the construction of an elevator shaft at the east end of the Natural History Museum Building in
Balboa Park in the spring of 1943, a stratum of volcanic ash was encountered which appears to be a
water-laid bentonite and is the most northerly known occurrence of volcanic ash in the San Diego
Pliocene. A sample was examined from the bottom of the shaft at a depth of 56 feet below the ground
floor of the building. This would be at an elevation of approximately 232 feet above mean sea level.
The general decrease in dip of the San Diego formation southeasterly from Balboa Park suggests
that this bentonite may be at about the same stratigraphic position as the bentonite mentioned above
which is exposed on Federal Avenue, several miles southeasterly from Balboa Park. The only other
bentonite known to us in the Pliocene of this region is that which occurs on the north and south sides
of Otay Valley. These bentonite beds are an exceptional phase of the lithology of the San Diego
formation, which is characteristically fine sand.

The sediments of the San Diego formation, taken as a whole, represent deposits which have
accumulated in relatively shallow water. The occasional cross-bedding, lenses and layers of conglomer-
ate, and the lack of shale, all point to a depth of water from low tide to possibly fifty fathoms. This is
borne out to a great extent by the fossils, including the Mollusca, Echini and Foraminifera. In this
ecologic aspect the San Diego Pliocene is unlike equivalent horizons in the Los Angeles basin, other
than the rare marginal shallow water facies.

Dr. Gordon A. Macdonald has made a petrographic study of samples of Pliocene sediments
collected by us at several localities. His report on these sediments is included here.

No. 15. Pliocene. Road-cut S-SE of Mercy Hospital on 6th Avenue Grade to Mission Valley.
This is above the Trophosycon beds. L. G. Hertlein and U. S. Grant, rv, collectors. August 12, 1937.

LIGHT MINERALS:

Quartz Seon esate Sse aol teva schy ates ALB
Orthoclaseyes tone eee, Fe a .. 29.9%
Oligoclases = eee hee coed Mya ere 19.9%
Al bite os fe fer ce oe IE csc ie HLS 5.0%
HEAVY MINERALS: .........0-2000000000-0+ Pein Sees, LY ETO

Magnetite—rare
Ilmenite—moderately abundant
Green hornblende—abundant
Actinolite—abundant
Epidote—moderately abundant
Zoisite—moderately abundant
Titanite—moderately abundant
Zircon—moderately abundant
Colorless garnet—moderately abundant
Glaucophane—rather rare
Brown biotite—rather rare
Brown hornblende—rather rare
Rutile—rare

“The grains are angular, with a few subangular. They vary from about .01 to .05 mm. in diameter, the
average being about .02 mm. The sorting is good. The feldspar is largely unaltered.” (G. A. Macdonald).

No. 16. Pliocene. Southeast corner of India and Upas Streets. One foot below fossil zone.
L. G. Hertlein and U. S. Grant, rv, collectors. August 13, 1937.

54 San Dreco Soctety oF Naturat History [Memorrs

LIGHT MINERALS:

Albite

AHAVY: MINERALS * (oUt PN. CeMeME E Ye
Magnetite—rare
Ilmenite—moderately abundant
Green hornblende—abundant
Actinolite—moderately abundant
Titanite—moderately abundant
Zircon—moderately abundant
Epidote—rather rare
Zoisite—rather rare
Brown biotite—rather rare
Glaucophane—rare
Colorless garnet—rare
Rutile—rather rare
Brown hornblende—rare

“The grains range from about .005 to .03 mm. in diameter, averaging about .01 mm. The sorting is good.
The grains are angular, and the feldspar is fresh.” (G. A. Macdonald).

No. 17. Pliocene. Paradise Valley, San Diego County, California. Just E-NE on hill on road
to Aloha. L. G. Hertlein and U. S. Grant, 1v, collectors. August 13, 1937.

“Pebbly arkosic sandstone. Microscopically, it consists largely of quartz, with abundant orthoclase, and
acid plagioclase (some grains partly sericitized). Smaller amounts of biotite, magnetite, microcline and muscovite
included in some of the quartz grains. The cement is silica. The grains are surrounded by a narrow rim of opal,
and the interspaces are filled with fibrous chalcedony.” (G. A. Macdonald).

No. 18. Pliocene. Loc. 417 (S.D.S.N.H.). Eight feet below fossiliferous conglomerate. Near
International Boundary. L. G. Hertlein and U. S. Grant, 1Vv, collectors. August 14, 1937.

LIGHT MINERALS:

Quarta yen nearer re rene ee ER a cle

Orthoclase

Oligoclase

AXcidiandesitie seen steer Ea tel tf 4.9%

AL bike pect oid eee on ee eee ere ee 2.0%
FIRAVY MINERALS ¢2) oe ete eee tens Mune tN 11.1%

Magnetite—rare

Ilmenite—moderately abundant
Brown biotite—abundant
Green hornblende—abundant
Titanite—moderately abundant
Zircon—moderately abundant
Actinolite—moderately abundant
Epidote—rather rare
Zoisite—rather rare
Rutile—rather rare

Brown hornblende—rare
Colorless garnet—rare

“The grains range in size from that of silt up to about .07 mm. in diameter, most of them lying between
005 and .07 mm. They average about .04 mm. This sorting is moderately good. The grains are largely angular,
with some subangular. The orthoclase is partially kaolinized.

“Epidote and zoisite are present in the Pliocene samples, and may have been derived from the older Eocene
sediments. However, the presence of abundant hornblende and actinolite, and less abundant glaucophane, biotite,
and other minerals not present in the Eocene sand examined indicate an additional source for much of the
Pliocene sediment. Glaucophane, of course, indicates a Franciscan derivation; but whether the mineral was
derived directly from its Franciscan source, or from older sandstone, is impossible to state.” (G. A. Macdonald).

A number of years ago brick was manufactured on a small scale in the canyon now traversed
by Reynard Way. This location is definitely in the Pliocene sediments which are fossiliferous nearby.

VotumeE II] MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Zocer7e-P/iocere

on
p
J

IN|
g

8
G
G
5
g
&
NK
E

DIAMOND

South of this point
Pliocene covered hy
beach sand except
for a small expos-
ure here

GARNET SPFIEAL. GARNET $ ST
August /928 =

Text Fic. 5. Sketch map of a part of Pacific Beach showing the location of the Pliocene
exposures in the beach bluffs.

Dp)

56 San Dieco Society oF Natura History [Memorrs

The National Brick Company of National City operates on about 13 acres in a Pliocene area. However,
most of the brick and tile plants utilize Eocene sediments, as related under our discussion of the Eocene.

PACIFIC BEACH AND SOLEDAD MOUNTAIN

Probably the best known section of the San Diego formation is that exposed at Pacific Beach.
There the yellowish and bluish-gray Pliocene sands rest upon an erosion surface of the fine shaly gray
and grayish-brown Eocene sandstones. The Eocene beds appear to strike N. 40° E. and dip about 12°
SW. The Pliocene beds strike N. 50° E. and dip 11° SW. There appears to be almost no difference in
dip between the two formations. The contact between the Pliocene and Eocene occurs in the beach
bluff several feet north of the mouth of a small arroyo which has been cut through the Pacific Beach
Terrace (Plate 8, figure 2, and Plate 9, figure 2). This contact dips below the beach about 1,740 feet
north of the west end of Law Street. The exposed thickness of the Pliocene section at Pacific Beach
is about 380 feet.

The underlying Eocene is a gray to yellowish-brown, very fine-grained shaly sandstone, well bedded
and stained by limonite along the bedding planes. These beds contain concretions, some of which contain
distinctive Eocene fossils. Deeper in the Eocene the strata are. somewhat faulted and crumpled. The
crumpling probably occurred in less competent members before consolidation took place. No typical
clay shale was observed in any of the strata. Lower in the Eocene section thick layers of conglomerate
appear. These outcrop in the higher cliffs at the northern end of Pacific Beach near Bird Rock.

The Pliocene and Eocene beds at Pacific Beach can be distinguished on both lithologic and
palaeontologic evidence. The Eocene beds are harder, finer-grained, more grayish-brown in color, contain
hard concretions and are less fossiliferous than the Pliocene. The very base of the San Diego formation
is a conglomerate about 3 or 4 feet thick, which consists of large well-rounded cobbles (Plate 9,
figure 2). This basal conglomerate rests upon an erosion surface of the Eocene, but due to lack of
clear bedding planes in the Pliocene and slight irregularities in the Eocene, the difference in dip is
difficult to detect with certainty, even instrumentally.

Overlying the conglomerate is a thick bed of rather massive yellowish and bluish-gray sandstone
which contains numerous valves of Pecten healeyi Arnold; these occur abundantly thirty or forty feet
above the base of the section. Above this loosely consolidated sand, are alternate layers of fossiliferous
grayish and yellowish sands and harder cemented layers containing molds and casts of fossils. Arnold
has already pointed out that Pecten stearnsii Dall and Pecten bellus Conrad are more numerous in the
upper beds in the section at Pacific Beach. Cementation has progressed in a very irregular manner
throughout much of the section exposed in the cliffs along the beach. This has resulted in hard,
ragged, projecting layers separated by loose sand (Plate 8, figure 2, Plate 10, figure 1; also Plate 11).
Some layers, however, have been uniformly cemented and their superior hardness has caused them to
weather out as shelves dipping south-east about 8°. One such layer appears near the top of the bluft
south of the west end of Law Street (projected) and continues visible for about 750 feet toward the
south before it dips below the sands of the beach. This particular bed contains numerous molds of a
Glycymeris and other mollusks.

About 1,200 feet south of the west end of Law Street the Pliocene dips below the beach sand but
the southern portion of the Pliocene is largely obscured by talus from the overlying Pleistocene. Just
south of Diamond Street the Pliocene strata apparently flatten out, for, although they are hidden
beneath beach sand, the cobble layer at the base of the Pleistocene continues and is visible just above
the beach at the foot of the bank south for some distance. Between Emerald and Feldspar Avenues,
at the foot of the embankment and beneath the Pleistocene conglomerate, a small ledge of Pliocene
is exposed. This might be due to a slight local upwarp in the strata or an irregularity in the surface
upon which the Pleistocene was deposited. No Pliocene is exposed south of Feldspar Avenue and the
embankment back of the beach gradually becomes lower until it disappears beneath the sand a short
distance south of Garnet Avenue pier.

The Pliocene strata at Pacific Beach contain a number of characteristic Pliocene fossils. Among
these are Pecten healeyi Arnold, Pecten bellus Conrad, Pecten stearnsii Dall, Pecten (Swiftopecten)

Votume II) Marine PLIOCENE OF SAN DIEGO, CALIFORNIA 57

parmeleei Dall (rare), Pecten (Lyropecten) cerrosensis Gabb, Pecten subdolus Hertlein, Arca (Ana-
dara) trilineata Conrad, Opalia anomala Stearns, Opalia varicostata Stearns, and Lovenia hemphilli
Israelsky.

ah yellowish-brown sandstones of Pliocene age are exposed on the south sloping spurs of Mount
Soledad, where they overlie the Eocene sediments. These beds are generally weathered or covered
with soil and brush, but they are well exposed in the sides of a small canyon about 3 of a mile west
of the mouth of Rose Canyon. The beds here are generally quite soft and contain well preserved
specimens of Pecten healeyi, Pecten stearnsii and Pecten (Swiftopecten) parmeleei.

SAN DIEGO MESA

South of Pacific Beach and Mount Soledad, no Pliocene rocks are exposed until the south bank of
the San Diego River Valley is reached. Here the Pliocene strata overlie the Eocene, beginning at a point
about one and a half miles up the valley from the Old Town Highway bridge. As the embankment
becomes higher toward the east, the Pliocene section thickens until the upper fifty feet or more are
Pliocene. The beds here are a light gray fine-grained sand with some nearly white beds. In the canyon
at the north end of Sixth Avenue and just east of Mercy Hospital, a thin stratum which is hardened
by cementation contains casts of mollusks, including the rather rare Trophosycon. The Pliocene-
Eocene contact is a short distance below this indurated fossiliferous layer, but the lithology of both
formations is so similar that it is difficult to detect the line of contact.

One of the striking features of the sedimentary rocks in the San Diego region is the similarity
between the Pliocene and the Eocene. It is possible that the Pliocene beds are reworked Eocene sediment
or came from the same or a similar source. This similarity, combined with the nearly horizontal
attitude of both formations over a large area, and the obscure unconformity between them, as well as
the scarcity of fossils at critical points, sometimes make the accurate determination of the contact a
matter of difficulty. In general, the hard concretions and the better bedding of the Eocene sandstones
distinguish them from the softer and less distinctly bedded Pliocene beds. Furthermore, no shale of any
consequence is found interbedded with the Pliocene sediments, as is the case in the Eocene beds in
that area. The small, hard, concretionary pebbles found on parts of the Eocene mesas are not present
on the Pliocene mesas.

With the exception of small areas in the northwest and northeast corners, the entire San Diego
mesa-lands, from the upper part of the south bank of the San Diego River Valley to the Mexican
boundary, are formed of Pliocene sediments of the San Diego formation.

In a road cut about two-tenths of a mile southwest of Alamo Drive and Center Street in East
San Diego, Dendraster sp. and Acanthina spirata were found at Loc. 1405 (C.A.S.). This indicates
a Pliocene age, while about one-fifth mile northeast a massive whitish-gray conglomerate outcrops, which
is apparently Poway, Eocene. Thus the Pliocene contact is in the immediate vicinity of that locality.

Terrace material caps much of the mesas, and Pleistocene deposits occur on some of the terraces,
but these do not comprise an important element in the thickness of the mesas. The Pleistocene sedi-
ments form, in general, a fringe along the western foot of the mesas.

Yellowish-brown and gray, fine to medium-grained sandstones are by far the most important sedi-
ments, in point of volume, of the Pliocene formation; but thin beds of gravel and lenses of conglomerate
are locally exposed. Some of the sands are noticeably micaceous, but this is not common.

Clay and shale are of rare occurrence in the San Diego Pliocene. No very large body of either
material was detected in any of the exposures visited during the field work. A peculiar colloidal clay
(bentonite), with a soft soapy feel when wet, occurs in a thin layer a little more than half way up
the mesa on the north and south sides of Otay Valley, a little over a mile west of the Otay Land

172

Tan, “Geological Features of Some Deposits of Bleaching Clay,” Amer. Inst. Min. Metall. Eng., Tech. Publ. 1139-H. 82, I. 89, p. 6,
figs. 7, 8, Jan., 1940.

58 San Drieco Society oF Natura History [Memorrs

lite.” This clay layer is but three to seven feet thick and lies interbedded with gray fine-grained Pliocene
sands. At two localities on the south side of the valley it was formerly mined for use in purifying
petroleum. More recently a smaller quarry on S. H. Perlmutter’s ranch on the north side of Otay
Valley, almost due north of the older quarries, has been intermittently worked by Standard Oil
interests. This stratum may be more widespread than present development would indicate, but it is
difficult to detect unless favorably exposed and it was not helpful as a definite horizon marker during
our field work. Where exposed in the sides of Otay Valley it can be seen forming a white line around
the mesa. At some places the beds may have a slight eastward dip. These occurrences, together with
the nine-inch bed of bentonite exposed on Federal Avenue just east of 35th Street in San Diego, and
the bentonitic bed penetrated by a shaft at the east end of the Natural History Museum Building in
Balboa Park, are the only clay material observed by us in the San Diego formation.

The well, Otay Mesa No. 1, drilled by the Itasco Petroleum Company in Section 33, Township
18 South, Range 2 West, San Bernardino Base and Meridian, showed, at a depth of 1,150 feet, a
core described as of soft gray sand, silt and shale, which is probably Pliocene in age. At a depth of 1,560
feet, a gray hard amorphous rock without bedded structure, apparently metamorphic, was reported. The
San Diego Oil and Gas Company’s Tia Juana River Well appears to have drilled through the base of the
Pliocene at a depth of 1,680 feet and penetrated Sespe or Poway Eocene to 3,040 feet, where Eocene
shale was encountered. At 3,400 feet the lithology suggests that Cretaceous may have been encountered
but these age determinations have not been checked by us.

Ellis'”* has furnished a series of logs of wells located in the San Diegan coastal region, some of
which indicate a great thickness of sedimentary rocks.'’* The data from these logs are mostly lithologic
in nature and there is no paleontologic evidence to permit a recognition of the Pliocene-Eocene contact.
The log of the Lo Tengo Oil Company’s well, which was located on the Otay Mesa a little less than
two miles north of the Mexican Boundary at Tia Juana, showed a thickness of sedimentary beds
of about 3,400 feet. Part of this may have been Eocene, possibly even Cretaceous in age. Ellis re-
produced logs of two other wells in the southern part of the Pliocene basin, one with a depth of 1,405
feet, the other 1,812 feet, both of which were in sedimentary beds at the maximum depths. It is un-
fortunate that these logs contain no fossil evidence by which the depth of the Pliocene sediments can
be determined. From the general structural relations of the Pliocene series in this basin as a whole
the writers are of the opinion that the San Diego formation in the vicinity of Otay Mesa attains a
thickness of about 1,275 feet.

Through the generous cooperation of Mr. J. E. Pettijohn we have been permitted to include here
portions of the geologic report of Mr. George H. Doane on the San Diego Gas and Petroleum Corpo-
ration’s Holderness No. 1 Well, located in the southeast quarter of Section 32, Township 18 south,
Range 2 west (San Bernardino Base and Meridian), about 16 miles south of the City of San Diego

173 Ellis, A. J., in Ellis, A. J., and Lee, C. H., U. S. Geol. Surv., Water Supply Paper 446, pp. 66-67, 1919.

174 Over fifty dry holes have been drilled in San Diego County in search of oil. We have looked over the logs of many
of these where they were available, but as most of the subsurface data consists of drillers’ descriptions of lithology without any
significant paleontologic facts little of value was obtained. The following are of some interest in presenting evidence in regard to
the depth of sedimentary rocks:

Community Oil Well Co., Scott Well No. 5. Lot 1194, T. 16 S., R. 3 W., S. B. B. and M., 1919. At 1,274 feet depth
shale and sandstone were logged.

Choate and Overbaugh, Encanto Well.. Tract 11, San Diego, 1925. Driller’s log from surface to 1,235 feet, where it was
reported to end in sandstone and limestone.

Paradise Oil Co., Well No. 1, Rancho de la Nacion. Elevation 290 feet, April 1, 1927. Penetrated 2,130 feet of sediments,
and at that depth hard limestone and sandstone were logged.

Borderland Exploration Co., Point Loma Well No. 1. Pueblo Lot 211. Abandoned 1932. Drilled to 5,101 feet where
brownish gray shale and sandstone were logged.

Borderland Exploration Co., Point Loma Well No. 2. Pueblo Lot 258. Three hundred feet northerly, 175 feet easterly
from the southwesterly corner on the northeasterly quarter of Pueblo Lot 258. Started Nov. 13, 1931, abandoned March, 1933.
Drilled to 2,610 feet, “gray shale” at bottom.

National City Oil Co., Well No. 1. Sect. 22, T. 18 S., R. 2 W., S. B. B. and M., 1933. Driller’s log from surface to
2,625 feet. Last hundred feet reported as “Red rock, cave. Shale-brown. Sand-fine. Lime, showing oil.”

The Petroleum World, Annual Review, 1936, p. 162, gives a brief list of dry holes in San Diego County with their total
depth but no logs.

See also, Hertlein, L. G., and Grant, iv, U. S., Calif. Journ. Mines and Geol., Vol. 35, no. 1, 35th Repr. Calif. State
Mineralogist, pp. 74-77, Jan., 1939, [received at library of the California Academy of Sciences Aug. 23, 1939}.

VotumE II] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 59

and one and one-half miles north of the International Boundary, elevation 20 feet. This is near the
mouth of the Tia Juana River. Mr. Doane began his examination when the well was drilling below
3,900 feet, but he also examined the higher cores and samples. From his examination of these cores

and samples he compiled the following geologic column:
Depth in feet Thickness in feet

PN URL Tes eget ee tle pe ee ee an i Se ee hee sy eee ae 0- 300 ? 300
Sania eggs Moris ya tifa ce rere rerers re ncaa be apriestnente hen 300-2,900 ? 2,600

La Jolla Formation

|pdatetay’ (Cray gay rly 15) nF hee eee Bee ee eed nr rearories +e eateries ernie ae 2,900-3,800 900

| YASS ET? Ment Soe ae eo en eee eee eee Bete See eee 3,800-3,900 100

LG sites? | Erefeene (a(oyay eeeate asi ase aie te ea eee BA ae ee ne Hee: 3,900-5,260 1,360

PICEA ICOM ESOPEN ATION eso eerste ete ee Son Ss ge scale cccenessnceeeeead 5,260-5,529 269

Pl ackalVlouantcinin bOtiiatio ne ser nee pecan tore emcee ec ce 5,529-6,332 803 plus

“Geophysical survey proves beds rising in southwesterly direction from Holderness No. 1 Well, the dip being
12-15 degrees which is the same as that seen in the cores of the well and definitely showing a structurally high area
to lie southwest of the well. No definite proof of closure is seen in the evidence.” (From report by G. H. Doane,
April 27, 1936).

According to a subsequent geophysical survey made by International Geophysical Company in
connection with underground water problems in the Tia Juana River Valley, the bottom of the valley
alluvium at the Holderness Well should be at about 115 feet below mean sea level. If this determina-
tion is correct, then the San Diego formation at this locality is a little thicker than the estimate given
in the table above or there are some post-San Diego beds present beneath the valley alluvium.

According to Mr. Doane’s report non-marine reddish colored beds were encountered below a depth
of 2,485 feet which he suggests might represent a thin “finger” of the “Sespe” formation. If the section
between 2,485 and 2,900 feet belongs to the “Sespe” formation or the Poway formation then the
San Diego formation may be only 2,185 feet thick or possibly much less. According to Mr. F. B.
Tolman, the greatest depth at which Pliocene fossils were encountered was 1,680 feet. If this latter
depth represents the base of the Pliocene sediments, then the San Diego formation would have a
thickness in this well of about 1,380 feet.

The report by Mr. Doane mentions the occurrence of slickensides and minor fracturing in cores
between depths of 5,018 and 5,042 feet, but we do not know whether or not this is significant of any
important faulting.

Distinctive Pliocene’ fossils occur at a number of localities in the mesas and canyons in the environs
of San Diego, southeast to the Chula Vista district and in the mesa along the Mexican Boundary.
These localities and the fossils will be described in detail in the systematic part of this paper, which is
planned for later publication. In some of the excavations along India Street, particularly at the corner
of Upas Street, Pecten healeyi and Pecten stearnsii are common, with occasional specimens of Ostrea
erici, Sinum scopulosum, Glottidia albida and others. In Balboa Park a large Dosinia is exceedingly
abundant just south of the west end of Cabrillo Bridge, and Merriamaster pacificus Kew has been
obtained in Cabrillo Canyon. Farther east and south numerous Pliocene species have been collected
by the authors, Messrs. Frank Stephens, Frank B. Tolman, E. H. Quayle and others. Pecten subdolus
Hertlein is common on Market Street one-tenth mile east of Euclid Avenue and Ostrea vespertina
Conrad is exceedingly common near the intersection of Thirty-fourth and Tompkins Streets. Farther
south the authors have obtained Dendraster ashleyi Arnold just west of Cockatoo Grove, Pecten healeyi
and Dendraster ashleyi ynezensis Kew in the Chula Vista District; and near the Mexican Boundary
about three-quarters of a mile from the sea, where the dip is about 9° to the west, Messrs. Tolman
and Quayle and the authors have collected Pecten bellus, P. healeyi, Pecten (Swiftopecten) parmeleei,
Arca trilineata calcarea and many other species.

Some geologists have suspected that a part or all of the mesa along the Mexican Boundary south
of the Tia Juana River is composed of Eocene strata. That this is not correct is proved by the Pliocene
fossils occurring just back of the beach (Locs. 294, 310 and 312, U.C.L.A.) and also the occurrence
of numerous specimens of Pecten (Patinopecten) healeyi from the bottom (60 feet) of David Small-
comb’s well just north of the Mexican Boundary, in the bottom of Matadero Canyon four-tenths of a
mile west of the United States-Mexico Boundary Monument No. 256 (see U. S. Geol. Surv., Topo-

60 San Dieco Society oF Naturat History [MeEmorrs

graphic Map of San Diego Quadrangle, Edition of June, 1904). The discovery by Mr. Quayle of
the occurrence of this characteristic Pliocene pecten in Smallcomb’s well definitely proves that all of
the mesa north of the International Boundary in this vicinity is of Pliocene age. These beds extend a
few miles south of the International Boundary, where they are overlain by Pliocene volcanic rocks.
A brief reconnaissance in the coastal region south of Tijuana indicates that the Pliocene beds extend
several miles south of the International Boundary where they rapidly become ashy. In the vicinity
of Rosarito, about 27 kilometers (17 miles) by road south of Tijuana, vesicular basic lava flows alter-
nating with ashy sands and silts form most of the terrain. Three miles south-southwest of Table
Mountain, a prominent peak 2,402 feet high, appears to be a volcanic neck from which lava flows
and tuffaceous deposits in that vicinity originated. These beds are inclined outward from this center,
dipping gently for the most part but steeply inclined near the old vent. Although recognizable fossils
were not found in these ashy deposits, their relationship to the marine Pliocene near the Boundary
suggests that they may be of late San Diego age. In the environs of La Mision (old San Miguel
Mission) about 64 kilometers (40 miles) by road south of Tijuana, a thick basic lava flow forms a
conspicuous surface surrounding occasional monadnocks of plutonic rock. This lava may also be
of Pliocene age.

In addition to the marine Pliocene invertebrates, Professor Loye Holmes Miller of the University
of California at Los Angeles has reported two extinct Pliocene birds from the San Diego formation.
These are Mancalla californiensis Lucas,'”’ of which the fragment of a humerus was collected at the
Euclid Avenue quarry, and Pliolunda diegense L. Miller,'’° described from a femur discovered in the
marine beds on Market Street near Euclid Avenue. The Mancalla, an extinct Auk, was originally
described from a humerus found well down in the Pliocene in the Third Street tunnel in metropolitan
Los Angeles. The Pliolunda diegense represents an extinct genus of Puffin. Both of these birds of
extinct genera seem to be unquestionably Pliocene in age.

The widespread though rather sporadic occurrence of Pliocene fossils is evidence of the extensive
distribution of the San Diego formation in this region.

STRUCTURE

The structure of the San Diego formation is comparatively simple. None of the Cretaceous or
Cenozoic sedimentary rocks in the San Diego basin have been greatly deformed since their deposition.
Possibly the lack of the effects of orogenic diastrophism is partly a reflection of the relatively thin
cover of incompetent sediments overlying the hard brittle crystalline rocks which make up the basement
complex. The total known thickness of all the unmetamorphosed sedimentary rocks resting on the
Black Mountain volcanics is less than six thousand feet in the San Diego region. In this respect
the San Diego basin is very different from some of the other California Tertiary basins, such as the
Ventura basin, where twenty to thirty thousand feet or more of sedimentary rocks accumulated before
they were folded and overthrust during the mid-Pleistocene Pasadenan orogeny.

At the northern end of the Pliocene basin, at Pacific Beach and on the south slopes of Mount Sole-
dad, the yellowish-brown Pliocene sands dip about 8° south-southeast. These Pliocene sands on the south
slope of Soledad Mountain are obscured by Pleistocene sands and terrace material before reaching
the shore of Mission Bay. This inclination represents a part of the gently dipping south limb of
the Soledad Mountain anticline, which has an axis trending northwest-southeast and which passes
just north of the summit of Soledad Mountain. The axis of this anticline plunges in both directions
from near the summit of Mount Soledad. The north limb has much steeper dips than the south limb,
particularly between the summit of the mountain and Rose Canyon, and general field relations suggest
that the force which produced the fold was ultimately dissipated by movement along the Rose Canyon
fault. This fault originated as a result of the same force which produced the fold. On the east side

175 Manealla californiensis Lucas, Proc. U. S. Nat. Mus., Vol. 24, p. 133, 1901. L. Miller, Condor, Vol. 35, no. 1,
pp. 34-35, Jan., 1933. — Woodring, U. S. Geol. Surv., Prof. Paper 190, pp. 6, 7, 1938.

176 Pliolunda diegense L. Miller, Trans. San Diego Soc. Nat. Hist., Vol. 8, no. 29, pp. 375-378, text figs. 1, 2, Dec. 15, 1937

Votume II] MarINE PLIOCENE OF SAN D1gGO, CALIFORNIA 61

°

QUATERNARY

Text Fic. 6. Areal geologic map and cross-section of Soledad Mountain. The areal distribution of the
Cretaceous, Eocene, Pliocene and Quaternary sedimentary rocks is shown on this map without attempt
to include all the terrace deposits. The Pleistocene and Recent deposits have been combined under
Quaternary and indicated where the areal extent is sufficient to be clearly shown on this small-scale map.
Horizontal distance of cross-section about four miles. Vertical and horizontal scales are the same.

of Rose Canyon, just above the first bend in the canyon, some of the beds of Rose Canyon shale dip
about 20° northeastward, reflecting the presence of the north limb of the subdued anticline east of the
Rose Canyon fault. The movement on the Rose Canyon fault was partly horizontal, the west side
moving northward, but the west side in the Mission Bay area also dropped down with respect to the
beds on the east. In Rose Canyon this fault can be detected by the difference in attitude of the beds
on opposite sides of the canyon. Farther south, along the east shore of Mission Bay, a continuation of
the fault is suggested by the former presence of a small spring near Morena and the steep (45°) south-
ward dip of a small tilted block which once formed a little knoll (now removed by grading) just north of
Old Town. The fault movement apparently accompanied the later stages of the folding or was
subsequent to it. Although the folding of the Eocene beds in Soledad Mountain may have begun at
a time preceding the last wave-truncation of the Kearny or Linda Vista Mesa, it must have continued
after the regression of the sea because the Pliocene beds on the southern lower slopes of Soledad
Mountain are dipping southward at an angle probably greater than their original inclination during

62 San Dreco Sociery of Natura History [Memoirs

deposition, and the terraces on Soledad Mountain are higher than those which may be their correlatives
in the mesa-lands to the east.

No Pliocene beds were detected on the north end of Point Loma which lies south of Mission Bay
(False Bay), and since the older beds on Point Loma have a prevailing eastward dip there is no con-
clusive surface structural evidence of a syncline in the Mission Bay region. At least the south limb of
such a syncline, if present, is not visible and the absence of Pliocene beds on the north end of Point
Loma can be readily explained by an east-west fault with the down throw on the north side. This
fault, if it exists, probably extends from the neighborhood of the present entrance to Mission Bay
eastward across the delta flats and an unknown distance up Mission Valley. If present, it is entirely
concealed beneath the Quaternary alluvium of the delta flats and valley bottom. Point Loma possibly
may be the remnant of an eastward tilted block bounded by faults on both east and west sides with
general north-south trends. The position of such faults would be beneath the bay and ocean, and, in
the northeast, beneath the Quaternary alluvium.

The Pliocene strata of the San Diego Mesa dip gently toward the south and southwest, amounting
to about 4° to 6 in Cabrillo Canyon, Balboa Park. At many outcrops the sands are not sufficiently
well bedded to permit careful measurements, but it is safe to say that the average of all outcrops
indicates a gentle inclination to the south or southwest. In general, the angle of dip decreases from
north to south in this embayment, and there is some evidence to suggest a decrease in angle of dip as
the eastern margin of the basin is approached. From Las Choyas south to the Mexican Boundary the
dip is generally less than it is in the northern areas, which indicates some flattening out of the beds
at certain places in the southern part of the basin. In this southern part, slight dips toward the east
and west were occasionally detected, but the inclinations were so low that little importance is attached
to them from a structural standpoint, except as indications of local irregularities or unevenness in the
beds. Steep dips in the beds at places along the south margin of Otay Mesa, such as occur near San
Ysidro, appear to be due to land-slides and not to orogeny.

Cross-bedding occurs locally in medium fine-grained gray sands and occasional lenses of pebbles
and cobbles. This is rare in the fine-grained yellowish-brown sands, and throughout the formation
it is not a common feature.

The Pliocene beds near the Mexican Boundary and about three-quarters of a mile east of the
beach have a dip of about 9° toward the west. The considerable thickness of conglomerates to the
east suggests that this dip may be due at least in part to the dip of foreset beds of the delta of the
ancient Tia Juana River. Likewise the conglomerates in the Pliocene west and southwest of La Mesa
may be part of the delta of the precursor of the San Diego River.

No faults of major importance were detected in the San Diego Pliocene Mesas. A small fault
with perhaps 15 feet displacement occurs in one of the clay pits on the south side of Otay Valley,
about a mile and a quarter west of the Otay Land Grant boundary line. Other such faults exist, but
they are small and of a local nature. There is some slight physiographic evidence of a fault obliquely
crossing the International Boundary in the mesa between Boundary Monuments Nos. 256 and 257,
but we were unable to detect corroborative geologic evidence of its existence in our brief field work
west of Tijuana. In the eastern margin of the basin the Pliocene sands rest on the eroded surface of
the older crystalline rocks with no indication of faulting. Between the Pliocene and Pleistocene there
is likewise no indication of faulting.

AGE AND CORRELATION

In the concluding part of this memoir the authors propose to present an analysis of the fauna
of the San Diego formation and a discussion of its age and correlation with some other important
Pliocene localities. As the present part of this work does not include a treatment of the fauna of the
San Diego formation it would be premature to attempt a thorough discussion of age relations at
this time. From what has been accomplished so far, the authors are convinced that the San Diego
formation is of Pliocene age and that it is probably equivalent, in part, to the Pliocene of Cedros
Island, Lower California, Mexico, the Pliocene of Elsmere Canyon near Newhall, Los Angeles

Vo.umeE II] Marine PLIOCENE OF SAN DIEGO, CALIFORNIA 63

County, the Pliocene near the mouth of Temescal Canyon, north of Santa Monica, and the Pliocene
north of Simi Valley in Ventura County. Although the upper and lower limits of the Pliocene series
in California may be subject to revision, the San Diego formation may be tentatively considered
middle Pliocene.

THE SWEITZER FORMATION

Most of the mesas in the San Diego region are overlain and capped by a formation of brownish-
red resistant sandstone and conglomerate, which, due to its superior hardness, often weathers out
as a prominent layer at the top of the mesas. The widespread distribution of this hard brownish-red
layer is a striking feature of the geology of the region. For this formation the name Sweitzer for-
mation’”’ was proposed by the senior author.

This formation is génerally readily distinguished from the finer-grained, softer, better sorted,
yellowish to bluish-gray sands of the San Diego formation, and a close inspection of favorable exposures
reveals an unconformity between the two. Such exposures occur near the heads of some of the lateral
canyons leading off Sweitzer Canyon and Cabrillo Canyon in Balboa Park, San Diego. As the lithology
is characteristically represented in natural outcrops and road cuts in and adjacent to Sweitzer Canyon,'”®
this area has been designated as the type locality for the formation.

The Sweitzer formation is constant in its position overlying the Pliocene sands of the San Diego
formation and is therefore clearly later in age. It also caps the Eocene on some of the mesas north of
the San Diego River. At a number of places it not only caps the higher mesas but extends down over
their margins onto the next lower terrace and apparently in some instances continues even lower.
In parts of Balboa Park in the City of San Diego the marine Pliocene beds have a dip of 6 to 8°
south-southwest and since the Sweitzer overlies them in a nearly horizontal attitude, the relationship
between these two formations is that of an angular unconformity'”’ (Plates 12, 13 and 16). Due to
lack of clear bedding planes this irregularity cannot always be readily observed, but where the contact
is well exposed in a fresh cut a definite line can be detected between the brownish-red sands and
gravels of the Sweitzer above and the yellowish to bluish-gray sands of the San Diego formation
below. In old cuts and weathered natural exposures the contact is often obscured by a ferruginous
mud which washes down from the Sweitzer and soil above onto the San Diego beds below. While
the lithology of these two formations is characteristically very different, sometimes the lower, less
conglomeratic part of the Sweitzer is well bedded and resembles the alternating sand and gravel layers
of the San Diego formation. In such cases a close inspection generally permits recognition of the
Sweitzer by its less well sorted and generally coarser sand, not to mention again the color differences.

The Sweitzer formation varies from a thin stratum to beds over 20 feet thick. The conglomerate
occurs as layers, lenses, or pockets in the sand, but is more commonly concentrated in the uppermost
part. The proportion of gravel and cobbles to sand varies greatly. The cobbles of the conglomerate
are generally well rounded and vary in size from a few centimeters in diameter up to boulders three
feet or more in maximum diameter. Their average size is perhaps less than one foot. They represent
a variety of rocks, including agglomerates, porphyry, and dense fine-grained igneous rocks. They are
all very hard, generally not strongly foliated, and cobbles of quartz diorite are exceedingly rare.

As already mentioned, the reddish-brown conglomeratic sandstone of the Sweitzer formation
occurs in some instances below the tops of the mesas, but except for the conglomeratic sands occurring
on the Sub-Otay Terrace and parts of the Avondale Terrace, the material on the lower terraces may
not belong to the Sweitzer formation. Apparently the lower level conglomerates and gravels are later
Pleistocene Terrace deposits, although they may have been derived in part from reworking of the
Sweitzer. In some localities what appear to be beach deposits on the mesas are associated with the

177 Hertlein, L. G., Stanford Univ. Bull., 5th Ser., Vol. 4, no. 78, p. 82, 1929.
178 Sweitzer Canyon is the large canyon east of Cabrillo Canyon in the northeast corner of Balboa Park. An excellent
exposure of the Sweitzer formation is present in a branch of Sweitzer Canyon locally known as Powder House Canyon.

179 This was noticed a number of years ago by Professor George D. Louderback (Trans. San Diego Soc. Nat. Hist., Vol. 2.
no. 3, p. 88, 1916).

64 San Dreco Sociery oF Naturat History {Memotrrs

Sweitzer formation. These deposits, which are younger in age, occasionally form definite beach ridges.
They are discussed briefly in the account of the physiography.

The gravels and sands of the Sweitzer formation are not continuous throughout the mesa regions.
On some of the eastern parts of the Otay Mesa the Sweitzer is apparently absent, but in all these
cases the elevations are below the general mesa level. This suggests that erosion has removed some
of the top of the terrace there. Moreover, those areas from which the Sweitzer is absent are, at least
in some cases, areas which were subjected to erosion by streams of an earlier interrupted cycle of
erosion described earlier in this paper.

The Sweitzer formation resembles somewhat the Eocene Poway conglomerate but the Sweitzer
is much thinner, the boulders and cobbles are not so well sorted, and the color is generally a brownish-
red, although in some localities the formation is a light gray. Furthermore, the resistant nature of the
Sweitzer appears to be due in many observed instances to a ferruginous mud cement. The Poway
conglomerate is better sorted and occurs in more massive, thicker beds. The latter, of course, is of
Eocene age and more comparable to the Sespe formation which is so well known to the north.

The soils developed from the Sweitzer formation are characterized by what soil experts refer to
as maturely weathered profiles with a clay or hardpan subsoil beneath the surface. Soils of the Redding
series and the Olivenhain series'*® are characteristically developed on the Sweitzer formation. Prairie
mounds frequently occur on these soils.

Origin of the Sweitzer Formation

From the standpoint of lithology it can be inferred that the Sweitzer formation represents a
decided difference in conditions of sedimentation from those which prevailed during the deposition
of the underlying finer-grained sediments. The coarser sandstone and the characteristic conglomerate
of the Sweitzer formation must have required strong currents to distribute the sediments over such
an area. This rather wide distribution could scarcely have been accomplished entirely or even largely
by rivers, since the strong currents required would presuppose a steep gradient which, in turn, would
have resulted in deeply entrenching the soft underlying sandstones. Although some entrenching of
the underlying San Diego beds has occurred in certain localities, such as northeast of Balboa Park,
it took place on a small scale and is not common. While any interpretation'*’ of past conditions based
on incomplete data must of necessity be an assumption, one might be inclined to accept the simplest
theory which will explain all the observed facts. In the present case, therefore, one may assume that
the Sweitzer formation represents distribution by ocean waves and near shore currents of coarse
material derived by wave erosion on the Poway conglomerate or by stream erosion on older rocks in
the mountainous region to the east. After the deposition of the uppermost San Diego beds, the region
was elevated sufficiently for wave erosion or sea floor scour to truncate the marine Pliocene and Eocene
beds. It is possible that this elevation was of a differential nature and that the mountainous region
far east of the area under immediate consideration was uplifted to a much greater extent than that
along the coast. At any rate the uplift may have been sufficient to greatly rejuvenate the streams and
enable them to transport coarser material such as medium to coarse-grained sand, gravel, and boulders.
This material would in that case have been deposited in relatively shallow water at the mouths of the
streams and from there distributed by the waves over a large area of the shallow bottom. Such an uplift,
rejuvenating the streams, would elevate the San Diego and the Eocene beds so that their upper surface
would be at or near sea level. It is probable that the northern part of the San Diego Mesas'** may have
been elevated more than the southern part, since the strata in the northern part, as in Balboa Park, have

180 See Storie, R. E., and Carpenter, E. J., “Soil Survey of the El Cajon Area, California,” U. S. Dept. Agric. Ser. 1930,
no. 15, 42 pp., map, | text fig.

181 For an excellent paper on this subject see “Marine and Terrestrial Conglomerates,” by J. Barrell, Bull. Geol. Soc. Amer.,
Vol. 36, no. 2, pp. 279-341, 6 text figs., 1925. (Ed. by C. Schuchert).

; 182 The term San Diego Mesas refers to all the mesa lands from the San Diego River Valley south to the Mexican Boundary
The mesa north of San Diego River Valley is generally referred to as the Linda Vista Mesa or Camp Kearny Mesa

VotumE II] MarINE PLIOCENE OF SAN D1kEGO, CALIFORNIA, 65

been more distinctly truncated. The present upper surface of the San Diego formation, then, probably
represents a plain of marine denudation although it may not have been exposed as dry land until
after deposition of the Sweitzer formation.

It is possible that parts of the San Diego formation were elevated slightly above sea level at the
close of the diastrophic movements which inaugurated Sweitzer time. If such did occur, the soft nature
of the San Diego beds resulted in their quick destruction by the waves and their reduction to a shallow
submarine platform. It is on this platform, possibly partly produced by wave reduction of loose sandy
cliffs and partly by wave scour on a very shallow soft bottom, that the Sweitzer formation was deposited.
Unfortunately no fossils were found in the Sweitzer formation. Considering the rarity of fossils in
general, their absence in this case is inconclusive. The water may have been decidedly brackish near
the mouths of the rivers, but it appears to the authors that the formation is at least partly marine in
origin. Its age can only be positively stated as later than San Diego and earlier than the uplifts which
are now represented by the Pleistocene terraces fringing the margins of the mesas.

At our request Dr. Gordon A. Macdonald kindly made a sedimentary analysis of a typical specimen
of the finer-grained part of the Sweitzer formation of Balboa Park. His report follows.

No. 19. Balboa Park, San Diego, California. Sweitzer formation on east side of street railway
cut, 75 yards south of trestle, about 200 yards south of north boundary of Balboa Park, 100 yards
east of Park Boulevard. U. S. Grant, tv, collector. Dec. 5, 1937.

LIGHT MINERALS:

Oa eerste Sh aoe ceca stages barb acen ence spasesrms 50:2 %
@rthoclaset cai ttt certs net ee 35.2%
Plagioclase (oligoclase to andesine) ... 10.1%
Microdline 22.c.c.0:06.edleess eee: pA et Saad ht Me 1.0%
Rock fragments ............ A Ter ae ee eo . 3.0%
LBA VIVGRWITINEIRATIG su Seferctecctne es ee ones ato acsncecarmucf-aracte cons 5 0.5%

Magnetite—abundant
Ilmenite—abundant

Green hornblende—abundant
Actinolite—abundant

Brown. biotite—abundant
Augite—moderately abundant
Epidote—abundant
Zoisite—rather rare
Glaucophane—moderately abundant
Zircon—moderately abundant
Pale pink garnet—rather rare
Titanite—rare

Brown tourmaline—rare

“Sorting is moderately good. The grains range in size from about .05 mm. to about .3 mm., and the
average size is close to 0.15 mm. The sample contains one sub-rounded pebble 2.5 cm. across. The grains are
largely angular in outline, but a few are subangular. They are weakly cemented together with brownish-yellow
clay material. In general, the grains appear quite fresh, although some of the orthoclase has been slightly kaolinized,
and the biotite is universally bleached to a pale golden-brown color.

“Lithologically, the Sweitzer sand is quite similar to the sands of the San Diego Pliocene which I examined
for you last semester. The heavy minerals include many of the same types. Like the San Diego Pliocene sands,
the original source of many of the minerals, such as glaucophane, was a metamorphic terrane of Franciscan type.
Other minerals, such as the biotite, and zircon, may have been derived from granitic source rocks. All, of course,
may have gone through an intervening sedimentary cycle, and in their present locus may have been derived from
older sedimentary rocks — possibly the Pliocene sands. The angularity and freshness of many of the grains,
especially of the feldspar, however, makes it seem improbable that they have suffered any very great degree of
re-handling. There is no evidence of wind action on the surfaces of the grains, and the degree of sorting suggests
water transportation. The angularity of the grains would appear to indicate that this transportation was not over
very great distances. The freshness of the minerals, particularly the feldspar, indicates that the rate of erosion
was rapid in comparison to the rate of weathering in the source area. All together, the Sweitzer sand is quite
similar to those of the Pliocene, and quite different from the sample of Eocene sand which I examined.” (G. A.

Macdonald).

66 San Dieco Society oF Naturat History (Memoirs

At a later date Dr. Macdonald made some supplementary remarks about the sample of Sweitzer
sediment he examined.

“Regarding the Sweitzer sand — I seem to have neglected to mention the color differences between the
Sweitzer and the Pliocene sands. As you say, they appear quite different. The Sweitzer is pale reddish-brown
in color, while the Pliocene sands are gray. Also, the one sample of the Sweitzer is less well sorted than the
majority of the Pliocene samples. The color indicates deposition under oxidizing conditions, and both this and
the fact that it is only moderately well sorted suggest that it is of non-marine origin, while the Pliocene is

marine.” (G. A. Macdonald).

PLEISTOCENE

The marine fossiliferous Pleistocene deposits of the San Diego region have been mentioned, briefly
discussed, or their fauna partially published by a number of authors, beginning with Dall'*’ in 1878.
From the “San Diego Peninsula,” now known as the Coronado peninsula, Dall listed over 40 species
which are of Pleistocene age, including in the lowest part of the beds the recent warm water species
Dosinia ponderosa Gray. In the same paper Dall also listed some upper Pleistocene fossils from the
mainland in the City of San Diego and from the upper beds at Pacific Beach. Later he definitely
referred these to the Pleistocene and correlated the horizon with the “San Pedro beds” in Los Angeles
County.'**

In his monograph on “The Paleontology and Stratigraphy of the Marine Pliocene and Pleistocene
of San Pedro, California,”"*’ Ralph Arnold described the Pliocene and Pleistocene of various other
localities in California, including those in the vicinity of San Diego. In describing the fossiliferous
Pleistocene sands and gravels overlying the San Diego formation at Pacific Beach, Arnold pointed
out their similarity to the “Upper San Pedro deposits,” now known as the Palos Verdes formation,'*°
but remarked'*’ that “the break between the faunas of the Pacific Beach Pliocene and the overlying
Pleistocene is much greater than that between the Deadman Island [Timms Point formation }'** and
its overlying Pleistocene (lower San Pedro series) layer.” This observation on the relative magnitude
of the faunal breaks in the two regions is amply borne out by all later paleontologic work. The
Arca (Anadara) trilineata, Pecten healeyi, Pecten (Swiftopecten) parmeleei, and other species
in the Pacific Beach Pliocene, so far as now known do not range sufhciently high in the Pliocene
to occur in the Deadman Island Pliocene [==Timms Point formation]. Furthermore, the Pacific
Beach Pleistocene is probably much younger than the lower San Pedro series of the Los An-
geles basin.

Arnold listed 59 species from the Pacific Beach Pleistocene to which Stephens'*® has added eight.
This fauna lacks some of the species so abundant at or diagnostic of other late Pleistocene localities
in the environs of San Diego, such as Chione gnidia, Amiantis callosa, Dosinia ponderosa and others.

183 Dall, W. H., “Distribution of California Tertiary Fossils,” Proc. U. S. Nat. Mus., Vol. 1, pp. 26-30, 1878. In this
paper, lists of both Pliocene and some Pleistocene fossils were included. Many years earlier Wm. P. Blake had called attention to a
“thick layer of large and small shells near the top of one of the banks bordering the beach, and about twenty feet above the water,”

at some undefined locality in the environs of San Diego, but he mentioned no species by name. (U. S. Pacific R. R. Repts., Vol 5,
pt. 2, pp. 128-129, 1857).

184 Dall, W. H., U. S. Geol. Surv., 18th Ann. Rept., Part 2, p. 335, 1898.

185 Arnold, R., Mem. Calif. Acad. Sci., Vol. 3, 420 pp., 37 pls., 1903. Reprinted as “Contributions to Biology from the
Hopkins Seaside Laboratory of the Leland Stanford Jr. University, No. 31,” 1903. See especially pp. 57-64.

186 Tieje, A. J., Bull. Amer. Assoc. Petrol. Geol., Vol. 10, no. 5, pp. 502-512, 1926. — Woodring, W. P., “Fossils from
the marine Pleistocene Terraces of the San Pedro Hills, California,” Amer. Journ. Sci., Ser. 5, Vol. 29, no. 171, pp. 292-305, 1 fig.,
March, 1935. — Willett, G., “An upper Pleistocene Fauna from the Baldwin Hills, Los Angeles County, California,” Trans. San
Diego Soc. Nat. Hist., Vol. 8, no. 30, pp. 379-406, pls. 25, 26, Dec. 15, 1937. — Delong, Jr., J. H., “The Paleontology and
Stratigraphy of the Pleistocene at Signal Hill, Long Beach, California,” Trans. San Diego Soc. Nat. Hist., Vol. 9, no. 25, pp. 229-252,
figs. 1-4, chart, April 30, 1941.

187 Arnold, R., Mem. Calif. Acad. Sci., Vol. 3, p. 58, 1903.

188 For a study of the fauna of these beds see: Clark, Alex, Trans. San Diego Soc. Nat. Hist., Vol. 7, no. 4, pp. 25-42,
1 map, | chart, Dec. 19, 1931.— Willett, G., “Additions to Knowledge of the Fossil Invertebrate Fauna of California,” Bull.
Southern Calif. Acad. Sci., Vol. 36, pt. 2, May-Aug. (issued Sept. 30), 1937, pp. 61-64, pls. 24, 25.

189 Stephens, Frank, “Notes on the Marine Pleistocene Deposits of San Diego County, California,” Trans. San Diego Soc.
Nar. Hist., Vol. 5, no. 16, pp. 245-256, text fig. 1, Aug. 5, 1929. See p. 254.

VotumE II] MarINE PLIOCENE OF SAN D1kEGO, CALIFORNIA 67

The ecologic conditions were probably quite different.

Very fossiliferous Pleistocene beds were formerly exposed at the foot of Twenty-sixth Street in
the southeastern part of the City of San Diego, but within the last few years this outcrop has been
completely covered with dredgings from San Diego Bay and it is not likely again to be exposed,
though it might be encountered in any wells or deep excavations if located nearby.'”°

Arnold (1903, p. 59) described this locality as follows:

“A bluff about eighteen feet high rises from the edge of the bay at the foot of Twenty-sixth street, San Diego,
and extends for two or three blocks both toward the east and toward the west from Twenty-sixth street, forming
the shore line along this part of the bay. At the base of this bluff, and covered by the water at high tide is a
stratum six inches thick made up almost entirely of the upper valves of Anomia limatula. No right valves were
found in this deposit, and this species seemed to be restricted to this layer. A stratum of fine, yellow fossiliferous
sand, four or five feet thick, rests upon the Anomia beds; and above the fossiliferous bed is about twelve feet
of fine brown sand, overlain by sandy soil. Dosinia ponderosa, Callista newcombiana, Mactra californica, and
Cardium procerum are the predominating species in the yellow sand stratum. The fauna of this locality is
equivalent to that of the upper San Pedro series at San Pedro.”

The most diagnostic species in these beds are Dosinia ponderosa, Cardium procerum, and Anomia
limatula. Stephens has described this old locality in his paper on the Pleistocene deposits of San Diego
County to which reference has already been made.

Stephens briefly described a number of other Pleistocene fossil localities in San Diego County,
from the Mexican Border to as far north as the San Dieguito Valley. One on the shore of Mission Bay
(formerly False Bay) is of particular interest because the shells form what is almost a coquina.

Stephens (1929, p. 253) described this locality as follows:

“Crown Point, formerly known as Bay Point, projects into Mission Bay from the north. Along the west
side of its southern extremity is a deposit of Pleistocene age. This is a cemented mass composed principally of
Donax laevigata, with a few Amiantis callosa, Chione succincta, Macoma secta, Paphia staminea and Tivela
stultorum scattered through the mass. In the lower part, at about high tide line, Dendraster excentricus is
common. The shell-bearing strata extend from the water ten or fifteen feet up the bank.”

The name Bay Point formation was recently proposed for these beds by the authors.'?!

From this deposit the late Professor Junius Henderson collected a specimen of Mellita longifissa
Michelin. The Dendraster reported by Stephens as excentricus is apparently diegoensis Kew. The abun-
dance of Donax gouldii (laevigata) suggests a correlation with the Spanish Bight Pleistocene, and the
fossils at both localities appear to indicate an open clean sandy beach.

All of these localities mentioned above, together with the Spanish Bight locality described below,
are probably essentially of the same age, although their faunas differ somewhat, due in all likelihood
to differences of ecology. A unique bed consisting almost entirely of a compact mass of Ostrea lurida
Carpenter, investigated by Stephens and the present authors a few years ago, occurs on the eastern
(bay) side of Point Loma along Rosecrans Street near Dumas Street. This oyster bed is also exposed
at the southwest corner of Rosecrans and Curtis Streets and it may have been more extensively exposed
before the construction of residences in this neighborhood. This is mentioned by Stephens in his
Pleistocene paper. It may represent a very shallow or brackish water facies of the upper Pleistocene.
Some distance north of this bed, (Loc. No. 70, S.D.S.N.H.). at the northeast end of Point Loma,
there formerly existed a little shelf upon which rested a few Pleistocene shells, including among them
the distinctive warm water Mexican gastropod, Turritella gonostoma broderipiana d’Orbigny. This
latter bed is perhaps somewhat different in age from the veneer of Pleistocene shells occurring on a
low terrace on the west side of Point Loma from the “Coal Mine” locality, briefly described by Berry!”
and by Stephens (1929, pp. 252-253) and which formed the basis of a longer faunal report by Webb.!”

190 C. R. Orcutt mentioned a number of species encountered in excavations in what are now business sections of San Diego.

See West Amer. Scientist, Vol. 11, Whole No. 84, pp. 15-16, Jan., 1900; Vol. 11, no. 4, Whole No. 89, pp. 36-38, May, 1900.

191 Hertlein, L. G., and Grant, 1v, U. S., Calif. Journ. Mines and Geol., Vol. 35, no. 1, 35th Rept. Calif. State Mineralogist,
p. 71, Jan., 1939, {received at the library of the California Academy of Sciences Aug. 23, 1939].

192 Berry, S .S., Proc. Calif. Acad. Sci., Ser. 4, Vol. 11, no. 18, pp. 412-414, May 16, 1922.

193 Webb, R. W., “Paleontology of the Pleistocene of Point Loma, San Diego County, California,’ Trans. San Diego Soc.
Nat. Hist., Vol. 8, no. 24, pp. 337-348, 1937.

68 San Drieco Society oF Naturat History [Memorrs

The species in the latter locality are not very different from those of the Recent fauna in this same
region and do not definitely suggest any significant climatic change.

The Pleistocene beds which have yielded the largest number of species occur on the west side
of Spanish Bight. This exposure is now partly obscured by slumping of the beds and by discarded

materials thrown over the cliff.
Arnold (1903, p. 59) described this locality as follows :

“The western shore-line of this inlet is a bluff varying in height from twelve to eighteen feet, while the
stratum at the base of the bluff forms the beach, and is covered by the water at high tide. This lowest layer is
composed of a firm, fine brown sand in which are imbedded numerous large Amiantis callosa, which have the
appearance of living shells, so naturally do they lie on the sand. An attempt to remove them, however, dispels
the delusion, for in most cases they are quite firmly imbedded in the sand layer.

“There are three feet of fine, soft unfossiliferous gray sand above the Amiantis layer, and this is overlain
by a deposit, varying in thickness from three to five feet, of soft gray sand, which is very fossiliferous near its
base and gradually grades into the almost unfossiliferous gray sand a few feet above. About twelve feet from the
base of the bluff is a layer from three to six inches thick containing numerous Donax laevigata cemented together.
This Donax layer is the uppermost fossiliferous stratum, the bluff above this being composed of unfossiliferous
sands. The fauna of the Spanish Bight deposits is similar to that of the upper San Pedro series at Los Cerritos,
and the deposits are probably of contemporaneous origin.”

Mrs. Kate Stephens, Curator Emeritus of Marine Invertebrates, San Diego Society of Natural
History, has collected and identified a large number of species from the Spanish Bight Pleistocene
deposits. We include here a list of species from this locality identified by Mrs. Stephens:

PELECYPODA

Aligena cerritensis Arnold
Amiantis callosa Conrad
Amiantis callosa Conrad var.
Anomia limatula Dall

Anomia peruviana d’Orbigny
Apolymetis biangulata Carpenter

Arca possibly gradata Broderip & Sowerby ;

Callithaca tenerrima Carpenter
Cardium procerum Sowerby
Cardium quadragenarium Conrad
Cardium substriatum Conrad
Chione gnidia Broderip & Sowerby
Cooperella subdiaphana Carpenter
Corbula luteola Carpenter
Crassinella branneri Arnold
Crassinella varians Dall
Cryptomya californica Conrad
Cumingia lamellosa Sowerby
Diplodonta sericata Reeve
Diplodonta subquadrata Carpenter
Donax californica Conrad

Donax gouldii Dall

Donax punctatostriata Hanley
Glans carpenteri Lamy

Glycymeris sp. (very small)
Kellia laperousit Deshayes

Lucina approximata Dall

Lucina nuttalli Conrad

Lucina tenuisculpta Carpenter
Macoma indentata tenuirostris Dall
Macoma nasuta Conrad

Macoma secta Conrad

Macoma yoldiformis Carpenter
Mactra californica Conrad

Mactra exoleta Gray

Mactra nasuta Gould
Modiolus rectus Conrad
Nucula suprastriata Carpenter
Nuculana taphria Dall

Ostrea sp. (rare)

Pandora punctata Conrad
Panope generosa Gould (one hinge only)
Pecten delosi Arnold

Pecten latiauratus Conrad
Pecten latiauratus monotimeris Conrad
Periploma planiuscula Sowerby
Petricola carditoides Conrad
Petricola cognata C. B. Adams
Pholadidea rostrata Valenciennes
Protothaca staminea Conrad
Psephidia lordi Baird
Rochefortia tumida Carpenter
Schizothaerus nuttallii Conrad
Semele decisa Conrad

Semele pulchra Sowerby
Septifer bifurcatus Conrad
Siliqua lucida Conrad

Solen rosaceus Carpenter
Spisula catilliformis Conrad
Spisula falcata Gould

Spisula planulata Conrad
Tagelus californianus Conrad
Tagelus dombeyi Lamarck
Tagelus subteres Conrad
Tellina bodegensis Hinds
Tellina buttoni Dall

Tellina meropsis Dall
Transennella tantilla Gould

Yoldia cooperii Gabb

VotumE II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA

SCAPHOPODA

Cadulus californicus ? Pilsbry & Sharp
Dentalium neohexagonum Sharp & Pilsbry

Dentalium pretiosum Sowerby
Dentalium semipolitum Broderip & Sowerby

GASTROPODA

Acanthina spirata Blainville

Acmaea depicta Hinds

Acmaea incessa Hinds

Acmaea scabra Gould

Acteocina carinata Carpenter
Acteocina culcitella Gould

Acteocina eximia Baird

Acteocina inculta Gould

Acteon punctocaelata Carpenter
Acteon punctocaelata coronadoensis Stearns
Acteon traskti Stearns

Aesopus chrysalloideus Carpenter
Aesopus oldroydi Arnold

Aesopus sanctus Dall

Aesopus sp.

Alvania compacta Carpenter
Amphissa columbiana Dall
Amphissa versicolor Dall

Barleeia californica Bartsch

Bivonia compacta Carpenter

Bursa californica Hinds

Bulla gouldiana Pilsbry

Caecum californicum Dall
Calliostoma gemmulatum Carpenter
Calliostoma supragranosum Carpenter
Calliostoma tricolor Gabb

Cerithidea californica Haldemann
Cerithiopsis arnoldi Bartsch
Cerithiopsis williamsoni Arnold
Clathrodrillia incisa ophioderma Dall
Clathrodrillia rhines Dall

Conus californicus Hinds

Conus californicus fossilis T. S. Oldroyd
Crepidula aculeata Gmelin
Crepidula adunca Sowerby
Crepidula excavata Broderip
Crepidula lessoni Broderip
Crepidula lingulata Gould

Crepidula onyx Sowerby
Crucibulum spinosum Sowerby
Cylichnella alba Brown
Cymatosyrinx empyrosia Dall
Cymatosyrinx halocydne Dall
Cymatosyrinx hemphilli Stearns
Cytharella densilineata Dall
Delphinula coronadoensis Arnold
Diodora murina (Carpenter MS.) Dall
Epitonium indianorum Carpenter
Erato columbella Menke

Eupleura muriciformis Broderip
Fartulum occidentale Bartsch
Forreria belcheri Hinds (one young shell)
Haliotis fulgens Philippi

Aalistylus subpupoideus Tryon

Hipponix antiquatus cranioides Carpenter

Homalopoma carpenteri Pilsbry
Homalopoma lurida Dall

Lacuna compacta Carpenter
Lacuna marmorata olla Dall
Liotia acuticostata Carpenter
Littorina scutulata Gould

Lottia gigantea Gray

Mangelia barbarensis I. S. Oldroyd
Mangelia interlirata Stearns
Mangelia striosa C. B. Adams
Margarites acuticostatus Carpenter
Marginella californica Tomlin
Marginella subtrigona Carpenter
Megasurcula carpenteriana Gabb
Melampus olivaceus Carpenter
Melanella hastata Sowerby
Melanella micans Carpenter
Melanella oldroydi Bartsch
Melanella rutila Carpenter
Metaxia diadema Bartsch
Micranellum crebricinctum Carpenter
Mitrella carinata Hinds

Mitrella gausapata Gould
Nassarius cerritensis Arnold
Nassarius cooperi Forbes
Nassarius fossatus Gould
Nassarius mendicus Gould
Nassarius perpinguis Hinds
Nassarius tegulus Reeve

Natica russa Gould

Norrisia norristi Sowerby
Odostomia fetella Dal! & Bartsch
Odostomia gravida Gould
Odostomia pedroana Dall & Bartsch
Odostomia sevilla Dall & Bartsch
Odostomia tersa T. S. Oldroyd
Odostomia (Odostomia) sp.

Olivella baetica diegoensis T. S. Oldroyd
Olivella biplicata angelena T. S. Oldroyd

Olivella biplicata parva T. S. Oldroyd
Olivella pedroana Conrad

Olivella porteri Dall

Phasianella pulloides Carpenter
Phasianella typica Dall

Polinices reclusianus Deshayes
Purpura festiva Hinds

Rissoina pleistocena Bartsch

Seila montereyensis Bartsch

Syncera translucens Carpenter
Tegula ligulata Menke

Tritonalia interfossa clathrata Stearns
Tritonalia interfossa minor Dall
Tritonalia lurida Middendorft
Tritonalia michaeli Ford

Trophon stuart: praecursor Arnold

70 San Dreco Soctety oF Naturat History [Memorrs

Truncatella californica Pfeiffer Turbonilla carpenteri Broderip & Sowerby
Truncatella stimpsoni Stearns Turbonilla laminata Carpenter
Turbonilla acra? Dall & Bartsch Turbonilla pecora T. S. Oldroyd
Turbonilla ambusta Dall & Bartsch Turbonilla stearnsii Dall & Bartsch
Turbonilla arnoldi Dall & Bartsch Turbonilla tenuicula Gould
Turbonilla asser Dall & Bartsch Volvulella californica Dall
Turbonilla attrita Dall & Bartsch Volvulella cooperi Dall
Turbonilla auricoma Dall & Bartsch Volvulella cylindrica Carpenter
Turbonilla buttoni Dall & Bartsch

AMPHINEURA
Ischnochiton conspicuus Carpenter Ischnochiton pectinulatus Carpenter

In addition to the fossils reported from the Pleistocene of Spanish Bight by Mrs. Stephens, Mr.
S. A. Glassell of Beverley Hills, California, has compiled for us the following list of fossil crabs

from this locality :

CRUSTACEA
Callianassa longimana Stimpson Heterocrypta occidentalis Dana
Callianassa stephensi Rathbun Libinia setosa Lockington
Cancer anthonyi Rathbun Portunus (Portunus) xantusii Stimpson
Cancer gracilis Dana Pugettia richiti Dana
Cancer jordani Rathbun Pyromaia tuberculata Lockington
Hemigrapsus nudus Dana Randallia ornata Randall

Hepatus lineatus Rathbun

Mr. Glassell informs us that of this assemblage of 13 species one, Callianassa stephensi Rathbun,'”*
is extinct. It has also been recorded from Nob Hill (lumber yard) northeast of San Pedro, in the
lower San Pedro formation, and at Signal Hill (or Los Cerritos), northeast of Long Beach, California,
in the upper San Pedro formation, upper Pleistocene. Two of the species, Hepatus lineatus Rathbun
(which also occurs in the Pleistocene of Signal Hill), and Libinia setosa Lockington (also known in
the Pleistocene of Santa Monica), now live in more southern latitudes. Apparently they are unknown
north of Cedros Island, Lower California, Mexico, and they are more common farther south. The
other species live in the waters off San Diego, California. In general this assemblage of crabs indicates
a depth of water of from low tide to 10 fathoms.

The evidence in regard to the temperature and depth of water offered by the crabs is in harmony
with that offered by the mollusks at Spanish Bight.

A specimen of a Camelops was discovered by Mr. Frank B. Tolman on the west side of Point Loma
in beds of Pleistocene age. It was found about 80 feet above tide and 100 yards back of the beach in
somewhat indurated clay. This is Locality 126, S.D.S.N.H., and was described by Frank Stephens
as occurring about two miles north of the Point Loma Lighthouse, at the mouth of a ravine that heads
in the hills, and nearly opposite Fort Rosecrans. The ravine has cut into the Cretaceous or Eocene
a few feet and then ends at the sea cliff. The Pleistocene fossiliferous strata are exposed on both sides
of the ravine, the lower beds being unusually thick and containing an abundance of small shells. As usual
the littoral front is solid rock with no beach. The contact is at an altitude of about 50 feet, and 40
feet below the surface of the mesa.

Regarding the specimen of Camelops Dr. Chester Stock has supplied the following statement:

“The specimen you refer to is a small jaw fragment of the right ramus containing two deciduous teeth,
representing a young animal. The material is not well preserved, but shows some resemblance to the comparable
parts in Camelops hesternus from Rancho La Brea.”

Many years ago a fossil horse tooth was obtained at a depth of 110 feet in a well at Coronado.
This was mentioned by C. R. Orcutt in the West American Scientist.'””

194 Callianassa stephensi Rathbun, U. S. Nat. Mus., Bull. 138, p. 122, pl. 18, figs. 5-8, 1926. “Spanish Bight, San Diego
Bay; upper San Pedro formation, Pleistocene series.” Also cited from other localities.

195 Orcutt, C. R., West. Amer. Sci., Vol. 7, Whole No. 51, p. 24, July, 1890. “When the Coronado Beach Co. were boring an
irtesian well on Coronado Beach, San Diego, in 1886, a fossil tooth was found at a depth of 110 feet which was presented by
H. L. Story to Mrs. R. S. Eigenmann. This has been examined by Prof. E. D. Cope, editor of the American Naturalist, who
identifies it as a left upper molar of an extinct species of horse, Equus excelsus.”’ (See also, Ellis, 1919, p. 64).

VotumeE II] Marine PLIOCENE OF SAN Dr&GO, CALIFORNIA 71

In summary, it can be said that so far as known the marine Pleistocene in the vicinity of San Diego
is of late Pleistocene age or at least represents a part of the upper half of that epoch. All the faunas
indicate relatively shallow water, probably from tide level to a hundred feet or thereabouts. Such
species as Donax gouldii Dall (cited as Donax laevigata Deshayes by earlier authors) are rather
sharply restricted in their habitat to sandy beaches between tides, and Amiantis callosa Conrad, Conus
californicus Hinds, and several others are now commonly found in very shallow water, from low tide
to possibly fifty fathoms. There are no species which indicate with certainty a greater depth. This
shallow water aspect is in harmony with the conditions of deposition reflected in the sediments, nearly
all of which are sands or gravels and broken shell fragments, often lenticular or cross-bedded.

All of the marine fossiliferous Pleistocene deposits which we have examined in this region lie
unconformably upon older rocks and have a horizontal attitude or only very low dips. They vary
in thickness from a thin veneer, such as at the “Old Coal Mine” locality on Point Loma, to twenty or
more feet, such as at Indian Point (foot of Twenty-sixth Street). Most of the deposits are but rela-
tively few feet above sea level although the Pleistocene localities at Torrey Pines and near Del Mar
are about 60 feet above tide level according to Stephens.

The climatic significance of the Pleistocene faunas of the San Diego region taken as a whole,
and exclusive of the “Coal Mine” Pleistocene veneer, can be interpreted in part by a correlation of
the Recent geographic ranges of the species occurring in the Pleistocene with the shallow water sea
temperatures prevailing within those ranges. Species which are confined in their bathymetric range to
relatively shallow water and are intolerant to a wide range of temperature are the best for this purpose.
For example, Chione gnidia,'*® which is a shallow water venerid, ranges in the Recent faunas only as
far north as Cedros Island (so far as known) where the mean annual sea surface temperature is about
63° F., but it ranges far south, apparently to Paita, Peru; so that its metropolis is no doubt within a
zone of water over 65° F., possibly 70° F., at the surface. Thus the presence of this species in the
Pleistocene of Spanish Bight, in the embankment on the east shore of Mission Bay,'”’ and in the
Pleistocene of Clark’s Well, Encinitas, is indicative of warmer marine waters in the San Diegan region
during a part of the Pleistocene. Dosinia ponderosa was reported to range north to San Diego by
Dall, but it is apparently unknown living north of Scammon’s Lagoon, approximately where the mean
annual sea surface temperature along the shore of Lower California is about 65°. This species is
present in the Pleistocene of Indian Point (foot of Twenty-sixth Street). A smooth form of Turritella
gonostoma Valenciennes was collected from the Pleistocene at the north end of Point Loma’”® by Mr.
Stephens and the authors. This is another warm water west Mexican mollusk unknown living north
of Scammon’s Lagoon, and the smooth variety (broderipiana d’Orbigny) occurring fossil at Point Loma
may be restricted to still more southern waters.

A consideration of the best available data'?? on marine sea-surface temperatures and the approxi-
mate near shore positions of the mean annual sea-surface isotherms along the west American coast
indicates how much shifting geographically of these temperature conditions might have taken place
since the deposition of the San Diego marine Pleistocene deposits. For example, the mean annual sea-
surface temperatures near shore along the west American coast appear to be as follows:

(Clamage ale WEL aN teg 2a) ee ti tee ernie ences en pen eee Serene eee 49° to 53° F.
Gapew Blanco m © reg oni s seas te scr rea ec nce evige ton fesecees cca nscecsesccscenswetoéer> DOs
California coast north of Cape Mendocino...........2---..-.-.---2----sseee eee pelle Js
ivstea fan (Capea? eas, SS ere UL dee aeasicesee RRs acer tire on rte eee Eee NE

196 This warm water species has been identified by Dall from three localities in the Pleistocene some distance north of San
Diego, Calif. These localities are as follows: NE 1/4 sec. 36, T. 11 S., R. 5 W., at an elevation of about 70 feet above sea level;
old beach ridge at the top of the cliffs 2 miles north of Del Mar; half a mile west of El Salto in a small deposit of dark loam. (See
Ellis, 1919, p. 69). Chione gnidia is definitely known to occur in the upper Pleistocene Palos Verdes (Upper San Pedro) formation,
in the San Pedro region and in the Palisades north of Santa Monica, Calif.

197 Loc. 64, S. D. S. N. H., See Stephens, F., Trans. San Diego Soc. Nat. Hist., Vol. 5, no. 16, p. 253, 1929
198 Locality 70, S. D. S. N. H.

199 We are grateful to Professor George F. McEwen of the Scripps Institution of Oceanography, to the late Dr. R. S.
Patton of the U. S. Coast and Geodetic Survey, and to Mr. W. L. Scofield, Supervisor of the California Fisheries Laboratory at

Terminal Island, California, for many marine temperature records.

72 San Disco Society oF Naturat History [Memoirs

wan Mateo) County: 2.2. cscsccstest scars teccnard peepee Sow k ee ene 2 Be le tie ale 54° F.
Justisontniofs Pointy Pinos! co c..ti rcs wee ntoaer tae ate eee ee Be hes ele arcane Sp helsh
|Byev ta Ve (loys (oo xls Wea cree Orr eer Peano oretter eM Sa eso teen Pepe PS net Eco Dias
Santa Barbara

CS) Phare Lea) tte se Re Dl Neate Pie EY elo 2 5 2 AN A ee Be

SanmDDie poy neat rskecn cece set iects ee ee rer ba :
Cedros Island, Lower California, Mexico.............-.-.::c1ecseceeseseeeeeeeeeneeeeees yeas 63° F.
Sanialonactowla goon. .e spec teasers sees ig RV ee oe San ALS Ct As 65° F.
Justinorto von Miagdal ental Bayan eects ane eee remeron: Ea aoe eed 68° F.
fuse south) ofalViagdalena sBay ss. ee vcee ces eceetettercaenc dscns ciasas teres cbcasccsncosereas concen age NE
just northvor Cape Sat lucasten eee tee Pk ae P75 Ee

It appears from this that the San Diego Pleistocene faunas containing Chione gnidia, Cardium
procerum, Dosinia ponderosa and Turritella gonostoma broderipiana represent a shift northward of
250 or 300 miles, or perhaps more.

The authors do not wish to give the impression that they consider the mean annual sea water
temperatures to be the only controlling factor in the distribution of these mollusks. It is quite probable
that the monthly distribution of temperatures, the times and magnitudes of sudden or slow fluctua-
tions, the temperatures during the spawning season, etc., are effective in limiting the geographical
distribution of these species, not to mention the host of other non-thermal factors which determine
their ranges. With very limited facts available on the many obscure phases of ecology, the mean
annual temperature is merely the most convenient set of conditions to use at the present time.

E. K. Jordan,”° Hertlein*”’ and Palmer and Hertlein*®? have described marine Pleistocene mol-
luscan faunas from several localities along the coast of Lower California, including San Quintin, San
Ignacio Lagoon, Magdalena Bay, and Maria Madre Island and Maria Magdalena Island of the Tres
Marias Group, and from Oaxaca, Mexico. The beds containing these faunas were considered to be
approximately equivalent at least in part to the warm water upper Pleistocene of San Diego, California.

200 Jordan, E. K., “Molluscan Fauna of the Pleistocene of San Quintin Bay, Lower California,” Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 15, no. 7, pp. 241-255, 1 text fig., 1 pl., April 26, 1926. See also, “The Geology of San Quintin Bay,” by G. E.
Manger, Johns Hopkins Univ. Studies in Geol., no. 11, pp. 273-303, 1 pl., 1934. — Jordan, E. K., “The Pleistocene Fauna of
Magdalena Bay, Lower California,” Contrib. Dept. Geol. Stanford Univ., Vol. 1, no. 4, 72 pp., 3 pls., 1936.

201 Hertlein, L. G., “Pleistocene Mollusks from the Tres Marias Islands, Cedros Island, and San Ignacio Lagoon, Mexico,”
Bull. Southern Calif. Acad. Sci., Vol. 33, pt. 2, May-Aug. [issued Aug. 31], 1934, pp. 59-73, 1 pl.

202 Palmer, R. H., and Hertlein, L. G., “Marine Pleistocene Mollusks from Oaxaca, Mexico,” Bull. Southern Calif
Acad. Sci., Vol. 35, pt. 2, May-Aug. [issued Sept. 10], 1936, pp. 65-81, 2 pls

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(Drawn sy E. H. Quayze)

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MarINE PLIOCENE OF SAN D1eGo, CALIFORNIA PLATE 4

Fic. 1. View looking north up canyon tributary to San Di
and about one-half mile east of S Thi

Fic. 2. View in Balboa Park, San Diego, showing the flat surface of the San Diego Mesa. The sharp edge
of the mesa at the top of the canyon side is due to the hard capping of the Sweitzer formation. (Photo by

L. M. Huey)

MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA PLATE 9

oundary
ght hand

Fic. 1. Terraces south of the flood plain of'the Tia Juana River
Monument 258 and just east of sandy beach. Pliocene fossils o
center of picture. (Photo, 1937)

Fic. 2. The Avondale Terrace on south side of Otay Valley. View south from about one mile east of Otay

(Photo, 1937).

MarINE PLIOCENE OF SAN D1gEGO, CALIFORNIA PLaTE 6

Fic. 1. Prairie mounds on mesa top about 1!4 miles west of Swee

water Reservoir. This view shows the
mounds extending over the edge of the mesa into the upper part of a

all canyon

Fic. 2. Prairie mounds on terrace about one-eighth mile north of Paradise Valley, east of National City
(Photo, 1937).

Marine PLIOCENE OF SAN D1EGO, CALIFORNIA PLATE 7

Fic. 1. Igneous and metamorphic rocks exposed at Sweetwater Dam. View east from nea
Pliocene sediment. The conical peak in the background is San Miguel Mountain. (Photo, 1

Fic. 2. Characteristic outcrop of pre-Tertiary igneous rocks exposed as a small island surrounded by
Pliocene sediment. View near Aloha, west of Sweetwater Dam

Marine PLIOCENE OF SAN DrEGO, CALIFORNIA PLATE 8

Fic. 1. Characteristic exposure of Rose Canyon shale member of the La Jolla formation on the east side of
Rose Canyon about one mile above its mouth. These Eocene beds are approximately horizontal, except those
at extreme right near Santa Fe Railway bridge, which have a steep northerly dip. (Photo, 1939).

epee
a Sr Es

Fic. 2. The Eocene-Pliocene-Pleistocene contacts in the bluff at the north end of Pacific Beach. The
Pliocene sandstone of the San Diego formation is coarser grained, more pebbly and thicker bedded than the
underlying Eocene. Contacts emphasized by black lines. (Photo, 1939).

MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA PLATE 9

Fig. 1. View looking north at Pacific Beach, showing the well bedded Eocene sediments overlain by
Pliocene basal conglomerate in upper right corner. (Photo, 1928)

Fic. 2. Pliocene basal conglomerate overlying Eocene beds at Pacific Beach. At this locality, the dip and
strike of the Eocene and the Pliocene beds are nearly the same. (Photo, 1928)

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MarINE PLIOCENE OF SAN D1gGO, CALIFORNIA PraTE 10

Fic. 1. View looking south at Pacific Beach, showing typical exposure of Pliocene fossiliferous sandstones
The Pliocene is here unconformably overlain by fossiliferous Pleistocene sands and gravel. (Photo, 1928)

Fic. 2. Outcrop of hard stratum of coarse sandstone on low spur of mesa between northeast tributaries of
Paradise Valley. This is an uncommon lithologic facies of the San Diego Pliocene. (Photo, 1938)

MarINE PLIOCENE OF SAN Deco, CALIFORNIA PiaTE 11

Fic, 1. Fossiliferous Pliocene sandstone on north side of Market Street Extension one-tenth mile east
of Euclid Avenue, San Diego. Pecten subdolus and other Pliocene mollusks occur here. (Photo, 1938)

Fic, 2. Conglomeratic yellowish and grayish micaceous Pliocene sandstone and two light colored limy
beds exposed on north side of Euclid Avenue about one mile south of University Avenue. Large barnacles
occur just above the bush near the base of the cliff. The uppermost five or six feet can be referred to the
Sweitzer formation. (Photo, 1938).

Marine PiioceNne OF SAN D1EGo, CALIFORNIA PraTE 12

Embankment in side of canyon in Balboa Park, San Diego showing reddish-brown
conglomerate and sandstone of the Sweitzer formation disconformably overlying the light

gray sandstone of the San Diego formation. Point of hammer indicates the contact. (Photo
by L. M. Huey).

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a *

Sa i a) qeeNwier« Yiur
Manus oft oats. e

MarINE PLIOCENE OF SAN D1kgGO, CALIFORNIA PraTe 13

Fic. 1. Reddish-brown coarse sand and conglomerate of the Sweitzer formation overlying the finer lighter
colored sands of the San Diego formation. Point of hammer is on contact. View in excavation near top of
at

Otay Mesa on West Park Avenue, 1.55 miles northeast from highway at San Ysidro. (Photo, 1937)

o
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Fic. 2. Pebbly sandy conglomerate of the Sweitzer formation overlying fine light gray sands of the
San Diego Pliocene formation on Richmond Street Extension in a tributary of Cabrillo Canyon, Balboa Park
The contact is clearly shown by the contrast in colors. (Photo, 1937)

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MarINE PLIOCENE OF SAN DIEGO, CALIFORNIA PiaTE 14

Fic. 1. Fossiliferous light gray coarse-grained cross bedded Pleistocene sands on the west side of Bay
Point (Crown Point), southeast of Pacific Beach. This is the type locality of the Bay Point formation. The
aeolian fine-grained sand which forms the subdued dune-like surface of Bay Point overlies these marine
Pleistocene beds. (Photo, 1937)

Fic. 2. Nearer view of beds of the Bay Point formation shown in figure |
Dendraster and Donax are very abundant in these beds. (Photo, 1937).

cross bedding

MarRINE PLIOCENE OF SAN D1IgGO, CALIFORNIA PraTE 15

Fic, 1. View eastward from northeastern low spur of Point Lom ss Ingraham Street (Mission Bay
Causeway) at intersection with Point Loma Boulevard. The } 1 : elta
flat between San Diego Bay and Mission Bay is shown in t
in the right background. (Photo, 1938)

Fic. 2. Bentonite quarry on north side of Otay Valley about two mile
interbedded with the Pliocene white sands of the San Diego formation.

“a

east of Otay. The clay layers are

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81 dLVId VINYOAT TV") we}aist(@| NV§ dO ANSOOITd ANIYV/

Additional copies of this publication may be obtained
at $1.50 each, postpaid,
from
The Director, Natural History Museum,
Balboa Park,
San Diego, California, U. S. A.

MEMOIRS
OF THE

SAN DIEGO SOCIETY OF NATURAL HISTORY

Volume II

THE GEOLOGY AND PALEONTOLOGY
OP THE MARINE PLIOCENE OF
SAN DIEGO, CALIFORNIA

PART 2a, PALEONTOLOGY

(CoELENTERATA, Bryozoa, BracHiopopa, ECHINODERMATA)

BY

LEO GEORGE HERTLEIN
California Academy of Sciences

AND

U. S. GRANT, IV
University of California at Los Angeles

SAN DIEGO, CALIFORNIA
PRINTED FOR THE SOCIETY
JuLy 7, 1960

AUG - 3 1960

\

HARYARD |
wv |

PUBLISHED WITH THE AID OF GRANTS
FROM THE

ELLEN BrowNninc Scripps FOUNDATION
AND THE

RICHFIELD Ort CoRPORATION

CONTENTS

PAGE

| EVSIRENOTNE Leeroy PE Oe MO ea ae ee Ee A ence 27/5)
Excl Wied omen ist, ee. Ob Me. weer 1) soo: Se la eh ae ane tenn 1 on 73
lascincationiand, Nomenclature... 74
AN 6) BYE gen fa eae ee eae Re ge a OO Woe 76
Systematic Descriptions... so en ae
Phylum Coelenterata ee aa eee <p Ere eT TS IAA ine eI ee 0)
Class Anthozoa Ehrenberg......... nar

Oroem Oclerdchinigibouenes 62 J oaiven 3 oa ee See De TT

Suborder Favitna Vaughan and Wells... cece 77

Ramil Oculinin ae kata. ie site aca en 77

Family Rhizangiidae d’Orbigny... 78

Suborder Caryophylliina Vaughan and Wells... - 80

Family Caryophylliidae Gray... oe ee oats SG

Suborder Dendrophylliina Vaughan and Wells. 81

Family Dendrophylliidae Gray... a4 81

PhiylumuBiryezod, Ehrenberg. nt Bee ee ee 85
Phylum: Brachiopoda Dumenl ORETETE RACE Ae vere 88
Glass narheulatatlusley 2 . 88

Order Atremata peechetini te 25s ee ee ce a Eao6

Superfamily Lingulacea Waagen... Bie een a ss
BatmilyaleineuddetGtayn see ee Oe 88

Glass Avirmlatasligleye tte wri 2 nie ee ee ee ee

Order elotrenmata Beecher 5 ee ee eee 0

Superfamily Terebratulacea Waagen..

amily iiereonate idacshangn eee ee 91

Phylum Echinodermata Bruguiere 0: 99
Glass steroideavburmelster. 2, a) Bek eee ees ee 99
OrdersPhanerozonia Sladen: -22.-8 et 98
RamilyActropectinidae Gray. 2 ke ee 99
GlassvEchinodedlbeskes.|.2. ne 0 SS LAP a 101

Order Gra arowdas Claus coe sae we eee ee | ae eee 102

Batnilya Grd aiid de tay ee i Ae oer nae A 102

iene anpacioida (aregOry < fee 107
amily Anbacidde. Gay 20.27 Se ee ee 107
(Dinka a EN OM G) C0 Reese a Pera ree 109
Suborder: Camarodonta Jackson. OD
amily chide Gray tne tie ee Se ee ee 109

Family Strongylocentrotidae Gregory .aexecnnneerneneeenrenennnnennnn 110

emily chinometnade Gray.o 20 113

@clerm Oly peasteroida Agassiz 2. os he 115
amily Wendrastentdde: Wambert =< ee eee lp)
Bamuly Mellidae Stetantnh 22 ee, ee 123
Order Spatangoida Claus................ FR ea, NE arc en eee 32198
Bamily: Spatenpidae Grays 2 ee ee 128
Family Loveniidae Lambert, emended Mortensen... 129
annily Scizustend ae: amet 2 arse ee 131

PD atess Oto Omen er ee ee eee bone 5 lena eer Senet ee bo ees following 135

FOREWORD

Part 1 of this memoir, issued August 30, 1944, contains a description of the general geology of
the San Diego region. The present part begins the systematic account of the Pliocene fossils of this
region, treating four phyla. Further experience in the field and laboratory has added to our
knowledge much that can be used to advantage in the portions of this work dealing with paleontologic
collections, their relationships, and their significance. We therefore hope that an improvement in presen-
tation will compensate for the delay in publication.

Since the appearance of Part 1, geological field work in the San Diego region, chiefly accomplished
or instigated by Professor E. Dean Milow, San Diego State College, has brought to light some further
details of structure. These details will be discussed more fully in a concluding portion of the memoir,
but three of them should be mentioned now. (1) The Soledad anticline is faulted and structurally more
complex than originally assumed. (2) The Mission Valley fault, indicated in our text figure (page 50 in
Part 1) as a hypothetical one, seems to have received some confirmation in the discovery of a down-
faulted wedge of Pliocene strata just north of the mouth of the valley. (3) Some windows of Eocene
sediments, identified from studies of microfossils, occur in the bottoms of some of the canyons in, north
of, and northeast of Balboa Park where our map indicated Pliocene. These small Eocene windows are
difficult to detect because of the lithologic similarity and the slight difference in dip between the Eocene
and Pliocene sediments.

A recent treatise on the archaeology of the San Diego region by Professor George F. Carter",
containing a discussion of the many terraces, may be of interest to the student of physiography or of the
Pleistocene and Recent history of that area. Professor Carter believed that the terraces record eustatic
changes of sea level rather than intermittent diastrophic uplifts.

ACKNOWLEDGMENTS

Many individuals have aided us during the preparation of this paper. Acknowledgment is made to
some of them in the text. Special acknowledgment is due Dr. G, Dallas Hanna, Curator, Department of
Geology, California Academy of Sciences, and Mr. Allyn G. Smith, Research Malacologist in the same
institution, who have aided and advised the authors on many occasions. Likewise, Miss Veronica Sexton
and Mr. Ignatius M’Guire of the library staff of the California Academy of Sciences have aided the
authors on many occasions with reference work and in securing needed literature. Mr. Alan E. Leviton,
Department of Herpetology, contributed valuable criticism concerning the section dealing with classifica-
tion and nomenclature. Dr. J. Wyatt Durham, Associate Professor of Paleontology, University of
California at Berkeley, identified specimens of corals for us, and Dr. John W. Wells, Cornell University,
and Dr. Donald F. Squires, American Museum of Natural History, furnished information concerning
certain species of this class. Some of the Bryozoa mentioned in the present paper were identified by Dr.
R. S. Bassler of the United States National Museum. Later, the same specimens and additional ones
were identified by Dr. John D. Soule, Allan Hancock Foundation, University of Southern California.
Mr. Fred C. Ziesenhenne of the same institution aided in the identification of some of the fossil echino-
derms and furnished important information after comparing them with Recent specimens.

We especially wish to acknowledge the courtesy of Mr. George P. Kanakoff, Curator of the Depart-
ment of Invertebrate Paleontology, Los Angeles County Museum, who lent us a fine series of excep-
tionally well-prepared corals, bryozoa, brachiopods, and echinoids, which were collected from the San
Diego formation. Dr. Hildegarde Howard of the same institution approved and facilitated the loan.

Fossils from the San Diego formation in the collections of the San Diego Society of Natural
History were lent us by Kate Stephens, late Curator of Marine Invertebrates; and Mr. Emery P. Chace,
present Curator, lent additional specimens and aided in other ways. Dr. William K. Emerson, formerly

(1) Carter, G. F., “Pleistocene Man at San Diego,” (Johns Hopkins Press, Baltimore), pp. 1-400, 6 tables, 96 figs., 1957.

74 San Dieco SocteTy OF NaTurAL History | Memoirs

Museum Paleontologist in the Department of Paleontology at the University of California, Berkeley,
California, (now with the American Museum of Natural History in New York), made available col-
lections in that institution, checked certain references for us, and aided us in various ways. Mr. Edwin C.
Allison and Mr. Joseph H. Peck, Jr., Museum Paleontologists in the same department, likewise aided
us whenever called upon for information. Dr. Hubert G. Schenck and Dr. A. M. Keen have given us free
access to the collections in the Department of Geology at Stanford University, and Dr. Willis P.
Popenoe and Mr. Takeo Susuki, Department of Geology at the University of California at Los Angeles,
made available the collections of that institution. Professor E. Dean Milow, San Diego State College,
furnished specimens of fossils from the San Diego formation as well as information concerning certain
localities in that area. Some specimens in the United States National Museum which were collected by
Henry Hemphill from the San Diego well, were lent us by Dr. Paul Bartsch, Curator of the Division
of Mollusks in the National Museum. Later, Dr. G. A. Cooper in the same institution lent specimens of
fossil brachiopods from Cedros Island, Lower California, Mexico, and from southern California.

The following individuals aided us in furnishing information concerning type specimens in their
respective institutions: Dr. Ruth Turner and Dr. Elizabeth Deichmann, Museum of Comparative
Zoology, Harvard University; Mr. Percy A. Morris, Peabody Museum of Natural History, Yale
University; Dr. Leslie R. Cox and Dr. Helen M. Muir-Wood, British Museum (Natural History),
London; Dr. André Franc, Museum National d’Histoire Naturelle in Paris. Dr. M. H. deLaubenfels,
Oregon State College, examined several specimens to ascertain whether these were bored by sponges. Mr.
Robert Lando, formerly a resident of San Diego, made available a manuscript containing the results of
his study of Recent and fossil mollusks at San Diego. The illustrations used in the plates are from
photographs made by Mr. Charles E. Crompton, Photographer, California Academy of Sciences.

CLASSIFICATION AND NOMENCLATURE

The ideal natural classification of all organisms would group together closely related forms and
separate those that are distantly or not related. Phylogeny, therefore, should be the fundamental basis
of a natural system of classification of all organisms. All modern systematists no doubt agree on this
point. They do not agree, however, concerning the. significance and interpretation of the various taxo-
nomic categories. Disagreements arise because the use of different characters leads to differences in
classification. Furthermore, the use of a few large inclusive groups by one systematist conflicts with the
use of more numerous finely divided, narrowly restricted groups by another systematist. Added to these
disagreements, the application of the International Rules of Zoological Nomenclature frequently leads to
complex legal questions which are variously interpreted by different authors or disregarded entirely
by others: even decisions of the Commission may be reversed by the Commission at a subsequent meeting.
This unfortunate state of affairs has led to much confusion, much argumentative literature, and an
altogether lamentable expenditure of time and effort without actually adding much that is fundamental
to our knowledge of nature. Consequently, in view of the present-day unsatisfactory condition of paleon-
tologic systematics, it seems desirable at the beginning of this portion of the memoir that its authors
express their viewpoints concerning nomenclature.

The authors subscribe to the general application of the International Rules of Zoological Nomen-
clature and most particularly to the rule of priority, which they are convinced is the cornerstone of these
rules. They have deviated from this rule only rarely and only where a long-established and well-known
name cannot be employed through strict adherence to this rule. Some of these well-known names later
may be validated either by a suspension of the rules (as in the case of the recent validation of Modiolus
Lamarck, 1799, replacing the earlier Volsella Scopoli, 1777) or through application of the “Principle of
Conservation” (Internat. Rules Zool. Nomencl., 1953, pp. 119-122). Suspension of the rules, however,
does not always stabilize nomenclature. Nicol’ pointed out that in one case such action resulted in the

(2) Nicol, D., Jour. Washington Acad. Sci., Vol. 40, No. 3, p. 82, March 15, 1950. See also McKerrow, W. S., “Fossil
Species and the Rules of Nomenclature” [in] “The Species Concept in Palaeontology” (P. C. Sylvester-Bradley, editor), Syste-
matics Association, Publ. No. 2, p. 122, 1956.

Votume II] MarINE PLIOCENE OF SAN D1EGo, CALIFORNIA 75

necessity for a change of the name of a well known genus (the replacement of Corbis Cuvier by Fimbria

Megerle von Miuhlfeld).

In the differentiation of genera and species, dependence has been placed upon a totality of charac-
ters, where possible, rather than upon one character. Characters of the shells and of other hard parts
that are preserved as fossils are given more emphasis than those of soft parts that can be studied only in
living material — and sometimes are given exclusive mention. Although the anatomy of soft parts is
very important in systematic zoology, traces of these are rarely preserved in rocks; and the paleon-
tologist must rely on what is usually preserved.

In the treatment of species, a more definite and objective concept than that of the genus, it is hoped
that an intermediate logical course has been followed, characterized neither by excessive “splitting” nor
by excessive “lumping.” The authors do not believe in naming new forms unless these are distinguished
by characters that appear relatively constant, but they are fully aware of the need of fine stratigraphic
delimitation of species based upon objective characters, no matter how small the differences may be.

Recognition of these species, whose stratigraphic ranges are often narrowly limited, is very useful
in determining chronological sequence of strata. Also important in deciphering the earth’s history are
some closely similar forms separated by great stratigraphic range, which may represent a long time
interval.

The paleobiologist emphasizes continuity within phylogenetic lineages of biologic forms by which
their evolution may be understood. The paleontologist, on the other hand, while recognizing the im-
portance of the phylogenetic sequence, looks especially for the breaks in the sequence which permit the
recognition of distinct morphological units whose geologic ranges are frequently short. On the basis of
such units, paleontologists are able to assign an age to and to correlate strata deposited approximately
contemporaneously. The viewpoint of the paleontologist has been ably presented by Weller'”?.

One of the most important aims of all paleontological work is the interpretation of the fossil record.
Precise correlation of strata, interpretation of the conditions under which these strata were deposited, and
elaboration of the geological history of local basins and provinces, should result in a knowledge of
the history of continents and oceanic basins.

For the ultimate aim to be more quickly realized, it is important to compare species and genera that
are now far separated geographically and to seek possible relationships. For this reason the authors have
here and there called attention to foreign species or to larger groups which are similar in morphology to
the local forms and which may later be discovered to have had a common origin. Such discoveries may
have an important bearing on inter-regional migration and geologic history. The excessive splitting of
genera and species and the resulting multiplication of names are often based either on characteristics
whose stability and importance are unknown or on the mere assumption that geographically distant forms
cannot be closely related. This practice may obscure natural relationships and indefinitely delay the
recognition of inter-regional relationships. It appears that the provincial attitude of some systematists has,
to an extent, concealed intercontinental faunal relationships‘) and thus made more difficult the work of
students of world history as a whole.

The authors have given considerable thought to the general arrangement of the information accom-
panying each species in this monograph. The type locality, the depository of the type specimen, the
geologic and geographic range of the species, and its occurrence in the Pliocene strata of southwestern
San Diego County, should certainly be included. The original descriptions are included for the con-
venience of the reader because many of the publications in which they appeared are rare and, to many
workers, not readily accessible.

Specific names printed in boldface type are for species which we have identified in the fauna of the
San Diego formation in or near San Diego and which we consider to be valid members of that fauna.
Specific names printed in standard type and enclosed in brackets | J are for species which have been

(3) Weller, J. M., “Paleontologist-Biologist and Geologist,” Jour. Paleo., Vol. 22, No. 2, pp. 268-269, March, 1948.

(4) See remarks by C. A. Fleming (Trans. Roy. Soc. New Zealand, Vol. 79, Pt. 1, p. 128, 1951) concerning subgenera of
Pecten. Also, “The Genus Pecten in New Zealand,” New Zealand Geol. Surv., Paleo. Bull. 26, pp. 7-10, 1957.

76 San Dtieco Socrety oF Naturat History [ Memoirs

reported from the San Diego formation in or near San Diego but of which we have not seen specimens.
These we consider to be doubtful or invalid members of the fauna.

Species whose records of occurrence in the San Diego formation are equivocal, such as “San Diego-
Purisima,”"”’ are not included in the present paper unless substantiated by specimens or by published
records definitely referable to the San Diego beds.

The references in the synonymy of the species, in general, have been restricted to the one containing
the original description, to those containing illustrations of the type specimen (or of typical specimens),
and to those in which the species is cited as occurring in Pliocene strata in the San Diego area. We also
have included some references which, although not citing the species from the San Diego formation,
contain information especially useful to others interested in the present faunal study. Additional
references pertinent to the general discussion of the species are placed as footnotes. This system of

citation of references is in general similar to that in the work of Anderson and Hanna’,

Descriptions of families, genera, and subgenera are followed by the name of the author and the
date when taken from works cited in the synonymy. Otherwise, the author and reference are cited.
Where the author is not cited, the descriptions have been drawn up by the present authors. Some of the
descriptions of the families and genera of Echinoidea in this work are taken verbatim from the excellent
catalogue by H. L. Clark”.

The systematic treatment of phyla of which we have made no special study is restricted to a brief
summary based upon the literature, or upon information furnished us by others where so indicated in
the text. A study of the Foraminifera has been entrusted to others and, if completed in time, it will be
included in this memoir.

ABBREVIATIONS
Abbreviations following locality numbers or specimen numbers refer to the following institutions:
(ANSP) — Academy of Natural Sciences of Philadelphia.

(CAS) — California Academy of Sciences.
(LAM) —Los Angeles County Museum Invertebrate Paleontology.

(SD) — San Diego Society of Natural History.
(SU) — Stanford University.
(UC) — University of California (Berkeley).

(UCLA) — University of California at Los Angeles.
(USGS) — United States Geological Survey.
(USNM) — United States National Museum.

(5) See Smith, J. P., “Geologic Range of Miocene Invertebrate Fossils of California,” Proc. Calif. Acad. Sci., Ser. 4, Vol.
3, pp. 161-182, April 5, 1912.

(6) Anderson, F. M., and Hanna, G. D., “Fauna and Stratigraphic Relations of the Tejon Eocene at the Type Locality in
Kern County, California,’ Occ. Papers Calif. Acad. Sci., No. 11, pp. 1-249, pls. 1-16, figs 1-10 in text, March 18, 1925.

(7) Clark, H. L., “A Catalogue of the Recent Sea-Urchins (Echinoidea) in the Collection of the British Museum (Natural
History)”, (London), pp. i-xxviii, 1-250, pls. I-XII, 1925.

Vovume IT] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 77

SYSTEMATIC DESCRIPTIONS
Phylum COELENTERATA Frey and Leuckart
Class ANTHOZOA Ehrenberg

Corals occur only rarely in Pliocene strata of California except in Imperial County, from which
region seven species and five varieties were described by Vaughan®. In 1903, Vaughan described
Caryophyllia californica®) from supposedly Pliocene beds at San Pedro, California, which are now
generally considered Pleistocene. Astrangia coalingensis Vaughan"’’’ was cited and illustrated in 1910
from strata now known to be of Pliocene age in San Joaquin Valley.

Nomland“” in 1916 recorded seven species from the Pliocene of California and Oregon. Durham
recorded one species"'”’ from the Pliocene of San Joaquin County, California, another ‘'*) from probable
late Pliocene in Humboldt County, and a third'’*) from the Pliocene of Carmen Island in the Gulf of
California. Durham”) summarized the ranges of genera of fossil corals occurring in that region. More
recently Durham and Barnard"’® dealt with the Recent species of stony corals of west American waters.
The Order Scleractinia was treated by Vaughan and Wells” in 1943 and by Wells"'® in 1956.

The papers mentioned above contain additional references to literature dealing with corals which
need not be mentioned here. Five genera, each represented by a single species, are known to occur in
Pliocene beds in southwestern San Diego County.

Order SCLERACTINIA Bourne
Suborder FAVIINA Vaughan and Wells
Family OCULINIDAE Gray

Colonial; colony formation by extratentacular (or rarely intratentacular) budding. Corallites
externally thickened by extensive, noncostate, granulated or smooth, dense (rarely vesicular) coenos-
teum. Septa exsert, formed by one fan system of simple trabeculae, margins minutely dentate, laterally
granulose or spinose. Pali generally developed. Columella papillose, trabecular, or absent. Endothecal
dissepiments, when developed, subtabular, thin, or replaced by stereome. (Wells, 1956.) Cretaceous to
Recent.

(8) Vaughan, T. W., “The Reef-Coral Fauna of Carrizo Creek, Imperial County, California, and its Significance,’ U.S.
Geol. Surv., Prof. Paper 98-T, pp. 355-376, figs. 43-46, pls. 92-102, March 3, 1917.

(9) Caryophyllia californica Vaughan in Arnold, Mem. Calif. Acad. Sci., Vol. 3, p. 87, pl. 3, figs. 2, 2a, June 27, 1903.
‘Deadman Island, off San Pedro, California.” “Geologic Horizon.—Pliocene.”

(10) Astrangia coalingensis Vaughan in Arnold, U.S. Geol. Survy., Bull. 396, pp. 30, 34, 152, pl. 23, fig. 3, 1909 (issued
January 15, 1910.

(11) Nomland, J. O., “Corals from the Cretaceous and Tertiary of California and Oregon,” Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 9, No. 5, pp. 59-76, pls. 3-6, January 20, 1916. es

(12) Durham, J. W., “A New Coral from the Pliocene of California,’ Jour. Paleo., Vol. 15, No. 3, pp. 278-279, figs. 1,
la, 2, May, 1941.

(13) Durham, J.W., “Pacific Coast Tertiary and Cretaceous Corals,” Jour. Paleo., Vol. 17, No. 2, pp. 196-202, figs. 1, 2,
pl. 32, March, 1943.

(14) Durham, J. W., “1940 E. W. Scripps Cruise to the Gulf of California. Megascopic Paleontology and Marine Stra-
tigraphy,” Geol. Soc. America, Mem. 43, Pt. 2, pp. i-viii, 1-216, figs. 1-3, pls. 1-48, tables 1-10, August 10, 1950.

(15) Durham, J. W., “Corals from the Gulf of California and the North Pacific Coast of America,” Geol. Soc. America,
Mem. 20, pp. i-v, 1-68, figs. 1, 2, pls. 1-14, March 26, 1947. [A paper by D. F. Squires dealing with corals from the Gulf of Cali-
fornia appeared recently (Bull. Amer. Mus. Nat. Hist., Vol. 118, Art. 7, pp. 367-432, text figs. 1-20, pls. 28-34, October 26, 1959).}

(16) Durham, J. W., and Barnard, J. L., “Stony Corals of the Eastern Pacific Collected by the Velero III and Velero IV,”
Allan Hancock Pac. Exped., Vol. 16, No. 1, pp. 1-110, pls. 1-16, August 18, 1952.

(17) Vaughan, T. W., and Wells, J. W., “Revision of the Suborders Families, and Genera of the Scleractinia,’ Geol. Soc.
America, Spec. Paper No. 44, pp. i-xv, 1-363, figs. 1-39, pls. 1-51, tables 1-3, March 12, 1943.

(18) Wells, J. W., “Scleractinia,’ Treatise on Invertebrate Paleontology (Geol. Soc. America and the Univ. Kansas), Part
F, Coelenterata, pp. F328-444, figs. 222-339, 1956.

78 San Dieco Society oF Naturat History [Memorrs

Genus ARCHOHELIA Vaughan

Archohelia Vaughan, U.S. Nat. Mus., Bull. 103, Pr. 9, p. 352, July 11, 1919. “Type-species. —Archohelia limonensis Vaughan.”
—Vaughan and Wells, Geol. Soc. America, Spec. Paper No. 44, p. 181, March 12, 1943. “Genotype (original designation) :
A. limonensis Vaughan 1919.”—Wells, Treatise Invert. Paleo. (Geol. Soc. America and Univ. Kansas), Pt. F, Coelenterata
p. F411, 1956. Type indicated as A. limonensis Vaughan.

Type species (by original designation) : Archohelia limonensis Vaughan, 1919, p. 353, pl. 80,
figs. 1, la, lb, 2, 3. Cotypes from “Niveau d, Moin Hill, Port Limon,” Costa Rica. “The geologic horizon
seems to be Pliocene.”

Rance: Middle Cretaceous to late Pliocene. Atlantic and eastern Pacific.

ORIGINAL DESCRIPTION: Archohelia differs from Oculina solely by having a persistent axial
corallite, whereas in Oculina there is no axial corallite. Pali or paliform teeth are present on all but
the last cycle of septa. Columella trabecular, with some papillae on its upper surface. (Vaughan.)

Remarks: Vaughan remarked that several Tertiary species of the eastern United States, which
were referred to “Astrohelia”’?) Milne Edwards and Haime and to Oculina Lamarck, should be
placed in Archohelia. About ten species of this genus are known.

Durham (1947, p. 7) indicated that the genus Archohelia occurs from Eocene to Miocene in the
western United States. The present record from the San Diego formation extends the range of the genus
into late Pliocene time in southern California.

2

Archohelia species

One well-preserved specimen of a coral and some imperfect ones were collected from Pliocene
strata at Pacific Beach by Frank B. Tolman and the late Ernest H. Quayle. These were found in a
light buff fossiliferous pebbly sandstone layer, 4 to 6 inches thick, 10 feet stratigraphically above the
Eocene-Pliocene contact, just north of the mouth of the ravine cutting the terrace two hundred feet
south of the lowest exposure of the contact. The beds also contained specimens of Opalia, echinoid
spines, and Bryozoa. ,

A manuscript in our possession contains a description by Quayle of this coral. We have searched in
vain for the specimens and illustrations of the Pliocene species described by Quayle. Lacking these we
have reluctantly decided not to publish the description which he prepared. It is our conclusion that
there can only be uncertainty concerning the identity of a species based upon a description but lacking
specimens and illustrations.

Quayle considered this coral to be a new species of Oculina Lamarck, closely resembling O.
peruviana Vaughan”), an Eocene species from Peru.

He also compared it with O. panzana Loel and Corey"), from early Miocene strata in San Luis
Obispo County, California. After discussing Quayle’s description with Dr. J. W. Durham, we agree
with him that Quayle’s coral probably is referable to Archohelia rather than to Oculina.

Family RHIZANGIIDAE d’Orbigny
(—Astrangiidae Verrill)

Colonial, ahermatypic. Colony formation by extratentacular budding from edge zone or stolon-like
expansions of edge zone, polyps remaining organically connected or not, colonies commonly consisting
of scattered corallites with no apparent connection, or united basally by coenosteum, or they form
compact masses. Corallites small and low. Septa composed of one fan system of simple or compound
trabeculae; irregular divergence of sclerodermites producing scattered lateral granulations and more or
less irregular marginal dentations. Columella trabecular, rarely solid or absent. Endothecal dissepiments
thin. (Wells, 1956.) Early Cretaceous to Recent.

(19) The original spelling of this genus name is Astrhelia.

(20) Oculina peruviana Vaughan, in Bosworth, T.O., “Geology of the Tertiary and Quaternary Periods in the North-West
Part of Peru,” (Macmillan & Co., London), p. 127, pl. 21, figs. 2-5, 1922. “Near Negritos; Clavilithes Series,” Eocene.

(21) Oculina panzana Loel and Corey, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 22, No. 3, p. 275, pl. 65, figs. 1-3,
December 31, 1932. “Vaqueros horizon, Lower Miocene only. Known only from the type locality, Carrizo Creek, west of the
Carrizo ranch house, south end La Panza Mountains.”

Votume IT] MariINE PLIOCENE OF SAN DreGo, CALIFORNIA 79

Genus ASTRANGIA Milne Edwards and Haime

Astrangia Milne Edwards and Haime, Comptes-Rendu Acad. Sci. Paris, Vol. 27, p. 496, November, 1848. No species cited.
— Vaughan and Wells, Geol Soc. America, Spec. Paper No. 44, p. 177, 1943. “Genotype (Genolectotype, Milne Edwards
and Haime, 1850): A. michelini Milne Edwards and Haime 1848.”—Durham, Geol. Soc. America, Mem. 20, p. 25, 1947.
“Genotype: Astrangia michelinii Milne Edwards and Haime.”—Durham and Barnard, Allan Hancock Pac. Exped., Vol.
16, No. 1, p. 60, 1952. “Genotype: Astrangia michelinii Milne Edwards and Haime.”—Wells, Treatise Invert. Paleo. (Geol.
Soc. America and Univ. Kansas), Part F, Coelenterata, p. F408, 1956. Type indicated as A. michelin Milne Edwards and
Haime.

Tyee spectes (designated by Milne Edwards and Haime, Palaeontogr. Soc. London, Vol. 3,
Monogr. British Fossil Corals, Introduction, p. xliv, 1850): Astrangia michelini Milne Edwards
and Haime. [Ann. Sci. Nat. Zool., Ser. 3, Vol. 12, p. 181, September, 1849. “Patria inconnue.—Coll.
Michelin.” For this species the authors cited Vol. 10, pl. 7, figs. 4, 4a, August, 1848. In the explanation
to plate 7, however, these figures are referred to “Oulangia Stokesiana’; and in volume 12, Oulangia
stokesiana is cited on page 183, also with reference to Vol. 10, pl. 7, figs. 4, 4a. “Habite les Philippines
(H. Cuming). —Coll. Stokes.” }

RANGE: Middle Cretaceous to Recent. In the western United States, Oligocene to Recent. Recent in
North, Central, and South America and the West Indies.

ORIGINAL DESCRIPTION: G. Astrangia. Différe du genre précédent [Rhizangia} en ce que les
polypiérites sont toujours unis entre eux par le base que est etalée, et que leur muraille est nue. (Milne
Edwards and Haime.)

SUPPLEMENTARY DESCRIPTION: Encrusting, subplocoid, corallites united basally by thin peritheca,
rarely solitary. All septa dentate. Columella papillary. Epitheca rarely developed. (Vaughan and
Wells, 1943.)

Remarks: The genus Astrangia is known to occur from Oligocene to Recent in western North
America. Twenty-one species of this genus have been recorded from marine waters between San Luis
Obispo Bay, California, and Zorritos, Peru, from the littoral zone to 91.5 meters (50 fathoms). Only
one of these species occurs off southern California; the remainder occur in tropical and subtropical
waters.

Astrangia coalingensis Vaughan was described from beds of late Pliocene age in the southern
portion of the San Joaquin Valley, and A. insignifica Nomland was described from beds of late Pliocene
age in Los Angeles. Several specimens questionably identified as the latter species were collected in the
San Diego formation.

Astrangia cf. A. insignifica Nomland
Plate 19, Figures 1-4, 7

The following is a reference to typical A. insignifica.
Astrangia insignifica Nomland, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 9, No. 5, p. 65, pl. 3, figs. 14, 15, January 20, 1916.

Tyee spECIMEN: No. 12010, Invertebrate Paleontology Collection, University of California.
Type Locauity: “in upper Fernando formation, Pliocene, at corner of Fourth and Broadway
streets, Los Angeles, California.”

Rance: Middle Pliocene in southern California.

OccuRRENCE IN THE SAN Disco FORMATION: Los ANGELES County Museum: Loc. 305, 2400 feet east and 1350
feet south of the northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topo-
graphic map, San Ysidro quadrangle, ed. 1943).

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

ReMarKS: Six specimens belonging to the genus Astrangia were collected by G. P. Kanakoff at
Loc. 305 (LAM), in the San Diego formation near the Mexican boundary. These specimens were
examined by Dr. J. W. Durham, who identified them tentatively with Astrangia insignifica Nomland.

80 San Dreco Society oF Naturat History [Memoirs

One specimen is 3 mm. high and its calice is 3.2 mm. in diameter. Another is 2.5 mm. high and the
diameter of its calice approximately 4.3 mm. The type specimen of that species is not perfectly pre-
served, but according to Durham (1947, p. 29), there appear to be about 48 septa. The present

specimens appear to have about the same number.

In addition to the original occurrence, Astrangia insignifica has been recorded by Soper and
Grant”) from late Pliocene strata at 5th and Hope streets in Los Angeles, California.

The imperfect state of preservation of the type specimen of Astrangia insignifica and the conse-
quent uncertainty concerning some of its specific characters led Durham to describe somewhat similar
specimens of a Recent coral from Ensenada, Lower California, under the name of Astrangia lajolla-
ensis), It is known to occur from San Luis Obispo Bay, California, to Santa Margarita Island,
Lower California, Mexico, from shore to a depth of 53 meters (29 fathoms).

Suborder CARYOPHYLLIINA Vaughan and Wells
Family CARYOPHYLLIIDAE Gray

Solitary and colonial. Colony formation by extratentacular (rarely intratentacular) budding,
forming phaceloid or dendroid colonies. Costae commonly covered by stereome or epitheca. Septa
exsert. Columella formed by curled trabecular laths, solid, spongy or absent. Pali or paliform lobes
common. Endothecal dissepiments developed in some groups. (Wells, 1956.) Jurassic to Recent.

Genus PARACYATHUS Milne Edwards and Haime

Paracyathus Milne Edwards and Haime, Ann. Sci. Nat., Ser. 3, Vol. 9, p. 318, May, 1848. Species cited: Paracyathus stokesii
Milne Edwards and Haime, P. desnoyersii Milne Edwards and Haime, P. procumbens Milne Edwards and Haime, P.
aequilamellosus Milne Edwards and Haime, P. pedemontanus Michelin, P. turonensis Milne Edwards and Haime, P. cary-
ophyllus Lamarck, P. brevis Milne Edwards and Haime.—Vaughan and Wells, Geol. Soc. America, Spec. Paper No. 44,
p. 206, 1943. “Genotype (genolectotype, Milne Edwards and Haime 1850): P. procumbens Milne Edwards and Haime,
1848. Eocene (Parisian). Hauteville (la Manche).”—Wells, Treatise Invert. Paleo. (Geol. Soc. America and Univ.
Kansas), Part F, Coelenterata, p. F424, 1956. Type indicated as Paracyathus procumbens Milne Edwards and Haime.

Type spectes (designated by Milne Edwards and Haime, Palaeontogr. Soc. London, Vol. 3,
Monograph of British Corals, Introduction, p. xv): “Typ. sp., Paracyathus procumbens, Milne Edw.
and J. Haime, loc. cit., tab. x, fig. 6” [Ann. Sci. Nat., Ser. 3, Vol. 9, p. 320, pl. 10, figs. 6, 6a, 6b,
May, 1848. “Fossile d’Hauteville.” Eocene. }

RANGE: Eocene to Recent. Cosmopolitan. Bathymetric range, 13 to 1472 meters (7 to 805
fathoms). (Vaughan and Wells.)

Description: Solitary, turbinate, fixed. Pali opposite all but last cycle, merging with columellar
papillae. (Wells.)

Remarks: Corals of this genus are attached whereas Heterocyathus Milne Edwards and Haime
and Deltocyathus Milne Edwards and Haime, also solitary, are free forms.

According to Vaughan and Wells about 40 species of Paracyathus are known. Three species
have been described as fossils from west American Tertiary strata, and six species have been described
as occurring in west American waters at the present time.

Paracyathus stearnsii Verrill

Plate 19, Figures 8-13

Paracyathus stearnsii Verrill, Proc. Boston Soc, Nat. Hist., Vol. 12, p. 393, May, 1869.—Durham, Geol. Soc. America, Mem.
20, p. 35, pl. 2, figs. 1, 2, 5, 6, March 26, 1947. Skidegate Inlet, Queen Charlotte Islands, British Columbia, to San
Pedro, California, Recent—Durham and Barnard, Allan Hancock Pac. Exped., Vol. 16, No. 1, p. 92, pl. 13, figs. 55a-e,
August 18, 1952. Numerous records cited, British Columbia to Dewey Channel, Lower California, Recent.

TYPE SPECIMEN: Location unknown to the present authors.
Type Locautty: “Monterey, California; Robert E. C. Stearns.”

(22) Soper, E. K., and Grant, U. S., IV, “Geology and Paleontology of a Portion of Los Angeles, California,” Bull. Geol.
Soc. America, Vol. 43, No. 4, p. 1064, December 30, 1932.

(23) Astrangia (Astrangia) lajollaensis Durham, Geol. Soc. America, Mem. 20, p. 28, pl. 2, figs. 14, 15, 18, 20, 21, March
26, 1947. “Loc. A-3982 (Ensenada, Lower California, Mexico).” “Collected along beach” (p. 44).

Votume II] Marine PLIOCENE OF SAN DreGo, CALIFORNIA 81

Rance: Middle Pliocene to Recent. Recent from Skidegate Inlet, Queen Charlotte Islands,
British Columbia, to 81 miles south of Dewey Channel, Lower California (between Natividad Island
and Point San Eugenio), in 22 to 894 meters (12 to 489 fathoms) ; mostly occurring between 27 and
110 meters (15 and 60 fathoms).

OccurRENCE IN THE SAN DreGo FORMATION: Los ANGELES County Museum: Loc. 305, 2400 feet east and 1350
feet south of the northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topo-
graphic map, San Ysidro quadrangle, ed. 1943).

ORIGINAL DESCRIPTION: Corallum with an expanded base, above which it is somewhat con-
stricted, and then expands rapidly to the edge of the broad, shallow cup, which is broad oval in form,
the edge bent into slight lobes or undulations. Exterior with very numerous, prominent, subequal,
scabrous costae, which extend from the summit to the outer edge of the base; on the basal portion
three or five smaller ones often alternate with one more prominent; toward the summit some of them
have a tendency to rise into crests; all are covered with several series of small, sharp granulations,
similar to those on the sides of the septa. Five complete cycles of septa, with some small ones in some
of the systems belonging to the sixth cycle, so that the whole number is about one hundred and twenty.
The primary and secondary septa are considerably broader than the others, broadly rounded and some-
what exsert at summit, narrowed toward the base and divided into two or three unequal, broad, stout,
paliform lobes, which are rough and lacerately spinulose at summit, and covered on the sides with
coarse rough granulations. The septa of the succeeding cycles are successively narrower, thinner, and
less exsert, with similar but smaller, rough, paliform teeth. Columella small, papillose, the papillae
slender, prominent, lacerately spinulose at summit.

Height .60; diameter of narrowest part .38 by .50; diameter of cup .50 by .72; depth of cup .25.
(Verrill.) [Dimensions in inches. }

Remarks: A number of specimens, most of them imperfectly preserved, were collected by G. P.
Kanakoff at Loc. 305 (LAM), near the Mexican boundary, associated with Balanophyllia elegans and
Dendrophyllia cf. D. oldroydi. The specimens were identified by J. W. Durham and appear to be
inseparable from the Recent Paracyathus stearnsii, which occurs in adjacent waters often at depths of
27 to 110 meters (15 to 60 fathoms). The calice of the largest specimen is 14.8 mm. in greater diameter
and 11 mm. in lesser diameter.

Paracyathus stearnsii differs from the Recent P. tiburonensis'** in possessing narrower costae,
with fewer and coarser granules on top of the ridge.

The late Pleistocene Paracyathus pedroénsis Vaughan’) was relegated to the synonymy of P.
stearnsii by Durham and Barnard (1952).

Suborder DENDROPHYLLIINA Vaughan and Wells
Family DENDROPHYLLIIDAE Gray

Solitary and colonial, mostly ahermatypic. Colony formation by intra- and extratentacular budding.
Wall formed by trabecular outer ends of septa and simple but very irregular synapticulae, irregularly
porous, usually thick, irregularly costate or covered by reduced costal granulations. Porous, layered
coenosteum in some colonial forms. Septa composed of one fan system of simple trabeculae, but
trabeculae tend to be very irregular, commonly not united closely in plane of septum and vertically
discontinuous with sclerodermites bending outward from septal plane, especially at periphery and near
columella. Septa strongly granulated laterally, mostly smooth marginally except peripherally and cen-
trally where irregular dentations occur, or wholly weakly dentate. Septa inserted following Pourtalés
plan (Fig. 239), at least in early stages. Columella trabecular and spongy, or absent. Endothecal
dissepiments thin and poorly developed. (Wells, 1956.) Late Cretaceous to Recent.

(24) Paracyathus tiburonensis Durham, Geol. Soc. America, Mem. 20, p. 35, pl. 3, figs. 5, 6, March 26, 1947. “Loc. A 3664,
depth 73 meters, southwest of Tiburén Island, Gulf of California.”

(25) Paracyathus pedroénsis Vaughan, in Arnold, Mem Calif. Acad. Sci., Vol. 3, p. 88, pl. 3, figs 1, la, June 27, 1903.
“San Pedro, California.” “Pleistocene.” (P. 46, species indicated as occurring at “Lumber Yard,” Upper San Pedro, Pleistocene. )

82 San Drieco Society oF Naturat History | Memoirs

KEY (26) TO THE GENERA OF DENDROPHYLLIIDAE
A. Solitary; corallum trochoid or subcylindrical (curved or straight) .........-2-..:csssosssessse- eeceseneeseeeeeeeees Balanophyllia
B. Colonial; corallum dendroid; extratentacular budding. ............2...1s-0e-sssscseescseecoeeeneecoeeeeseneseneeseeeeee Dendrophyllia

Genus DENDROPHYLLIA de Bilainville

Dendrophyllia de Blainville, Dict. Sci. Nat., Vol. 60, p. 319, 1830. Species cited (p. 320): D[endrophyllia}. ramea Linnaeus,
D. semiramea de Haan, D. cornigera Lamarck, D. rubeola Quoy and Gaimard, D. digitalis [Blainville}], D. irregularis
{Blainville], D. variabilis {Blainville]. [The latter three species, fossil forms, were attributed to Guettard but since he had
cited the species in the French language they are not acceptable in biological nomenclature. Blainville is considered to be the
author of these species]—WVaughan and Wells, Geol. Soc. America, Spec. Paper 44, p. 237, March 12, 1943. “Genotype
(genolectotype, Milne Edwards and Haime, 1850): Madrepora ramea Linnaeus 1758. Recent. Mediterranean and eastern
North Atlantic.”—Wells, Treatise Invert. Paleo. (Geol. Soc. America and Univ. Kansas), Part F, Coelenterata, p. F435,
1956. Type indicated as Madrepora ramea Linnaeus.

Type spectes (designated by Milne Edwards and Haime, Palaeontogr. Soc. London, Vol. 3,
Monogr. British Fossil Corals, Introduction, p. liii, 1850) : “Typ. sp., Dendrophyllia ramea, Blainville,
loc. cit.; Milne, Edw., Atlas du Régne Animal de Cuvier, Zooph., pl. LXXXIII, fig. 1” [—=-Madrepora
ramea Linnaeus, Syst. Nat., ed. 10, p. 797, 1758. “Habitat in O. Americano & Asiatico.” Ref. to
Pet. Gaz., t.76, fig. 7. — Also illustrated by Schmidt in Brehms Thierleben, ed. 2, Abt. 4, Bd. 2, p. 486,
figs. A, B, 1884. — Doderlein, Mitteil. Zool. Station zu Neapel, Bd. 21, No. 5, p. 147, Taf. 9, figs.
90-92, September 6, 1913 (as Dendrophyllia ramea). Mediterranean, in 180 to 270 meters (98 to
148 fathoms), Atlantic at Madeira. }

RANGE: Eocene to Recent. Cosmopolitan. Bathymetric range, littoral zone to 1372 meters (0 to
750 fathoms). Temperature range, 11.2-27.3° C. (52-81° F.). (Vaughan and Wells.)

Description: Structures like Balanophyllia, but forming dendroid colonies by extratentacular
budding from the edge-zone, the polyps remaining organically connected. Columella small. (Vaughan
and Wells, 1943.)

Remarks: About 25 species of this cosmopolitan genus have been described. Three species are
known to occur at the present time in west American waters between southern California and the Gulf
of California. One of these occurs in beds of Pliocene age in California. Woodring recorded an
unidentified species of Dendrophyllia in beds of Pliocene age in the Santa Maria district, Santa Barbara
County, California.

Dendrophyllia cf. D. oldroydi Faustino
Plate 19, Figures 5, 6, 15

The following are references to typical D. oldroydi.

Dendrophyllia oldroydi Faustino MS [misspelled Faustina} in I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1,
No. 1, pl. 49, fig. 7, 1924. [No description. ]—Faustino, Philippine Jour. Sci., Vol. 44, No. 3, p. 286, pl. 1, fig. 2, March,
1931. “Sunken Valley, between San Pedro and Redonda [Redondo], California, 200 fathoms; deep water off San Diego,
California.”—Durham, Geol. Soc. America, Mem. 20, p. 38, pl. 10, figs. 1, 9, March 26, 1947. “200 fms. off San Pedro,
Calif. (holotype); numerous records by fishermen from ‘deep water’ off the Southern California coast; 100 fms. off Hunt-
ington Beach, California.”

TYPE SPECIMEN: Holotype missing from Stanford University collection. Paratype, No. 5905,
Department of Paleontology Type Collection, Stanford University; specimen illustrated by Faustino,
1931 (according to A. M. Keen, oral communication, 1957).

Type Ltocatity: “200 fathoms off San Pedro.” California.

Rance: Middle Pliocene to Recent. Recent, off San Pedro to San Diego, California, in 183 to
366 meters (100 to 200 fathoms).

OccuRRENCE IN THE SAN D1eGo FORMATION: Los ANGELES County Museum: Loc. 305, 2400 feet east and 1350
feet south of the northwest corner of Sec. 8, T.19S., R. 2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topo-
graphic map, San Ysidro quadrangle, ed. 1943).

Description: Colony high and arborescently branched. Two specimens are in the Stanford
University collection; one is 30 centimeters high and 38 centimeters across in one direction, the other
is 24 centimeters high with branches not so numerous and with a thick base. The branching is irregular
and apparently takes place wherever there is opportunity. Budding takes place at the base of the branches
and at the sides. The main stem of the first specimen, which is regarded as the type, is 1 centimeter, and

(26) Adapted from Vaughan and Wells, 1943.

VotumeE II] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 83

the branches are about the same size. The base of the second specimen is 3 centimeters and the main
branches 2 centimeters.

The corallites are subcircular, the largest are 1 centimeter in diameter, and project as much as
7 millimeters above the base. Wall perforate, covered externally with fine subequal costal striations,
somewhat scabrous, corresponding to all septa. Corallites not very deep, with a jagged edge.

Septa in four complete cycles, often with narrow rudimentary septa corresponding to the fifth
cycle. The form and arrangement of the septa are clearly shown in the figure.

Columella well developed, rather prominent, sometimes occupying about a third of the breadth
of the corallite, composed of convoluted and contorted porous plates. (Faustino, 1931.)

Remarks: Two imperfect branching specimens, tentatively assigned to this species, the larger
specimen about 19 mm. long, and the larger calice about 10.5 mm. wide, were collected with specimens
of Balanophyllia elegans Verrill at Loc. 305 (LAM) in southwestern San Diego County. Dr. J. W.
Durham, University of California, considered these specimens to be comparable to Dendrophyllia
oldroydi. The only other record of this species as a fossil is from beds of late Pliocene or early Pleisto-
cene age in Humboldt County, California”.

The solid character of the corallum, the varyingly exsert septa, the three sizes of costae, and the
more rounded calices serve to separate D. oldroydi from D. californica Durham®), which was described
from off the west coast of Lower California. Dendrophyllia cortezi Durham and Barnard‘°?’ was
described from “South of Isla Partida, 70 fms.” in the Gulf of California, and, according to its authors,
“is separated from D. oldroydi Faustino by the dentate third cycle septa, by the longer and more slender
calices, and by the upper margins of the calices being much less serrate in appearance.”

Genus BALANOPHYLLIA Searles Wood

Balanophyllia Searles Wood, Ann. and Mag. Nat. Hist., Vol. 13, No. 81, p. 11, January, 1844. Sole species, Balanophyllia caly-
culus Searles Wood.—Vaughan and Wells, Geol. Soc. America, Spec. Paper No. 44, p. 236, March 12, 1943. “Genotype
(monotypy): B. calyculus Wood 1844.”—Durham, Geol. Soc. America, Mem. 20, p. 40, March 26, 1947. “Genotype:
Balanophyllia calyculus Searles Wood.” —Wells, Treatise Invert. Paleo. (Geol. Soc. America and Univ. Kansas), Part F,
Coelenterata, p. F433, 1956. Type indicated as B. calyculus Wood.

Type species: (by monotypy): Balanophyllia calyculus Searles Wood, Ann. and Mag. Nat.
Hist., Vol. 13, No. 81, p. 11, January, 1844. (Ref. to Mag. Nat. Hist., Vol. 3, p. 272, fig. 60d, 1830).
“Sutton.” “Red Crag.” England. [Late Pliocene or Pleistocene}. [Illustrated by Milne Edwards and
Haime, Palaeontogr. Soc. London, Vol. 3, Fossil Corals of Great Britain, Corals of the Crag, p. 9, pl. 1,
figs. 3, 3a, 3b, 3c, 3d, 1850. Red Crag of Sutton, late Pliocene or early Pleistocene. — Neaverson, Strat.
Paleo. (Macmillan and Co.: London), p. 28, fig. 4 (upper right), 1928. ]

RANGE: Eocene to Recent. Recent world-wide, at depths of 0-1100 meters (0-601 fathoms) and
in temperatures of 6.7-27.7° C. (44-82° F.), according to Vaughan and Wells (1943). In the western
Americas from British Columbia to La Plata Island, Ecuador, and the Galapagos Islands, intertidal
zone to 605 meters (331 fathoms), usually in about 91 meters (50 fathoms).

Description: Simple, solitary, conical corals, curved or straight, attached by base; septa very
numerous, closely crowded and partly fused together; columella spongy; epitheca often present, structure
porous; costae on exterior corresponding to the septa. (Adapted from Vaughan and Wells.)

Remarks: About 50 species of this genus are known according to Vaughan and Wells. Two
species have been described from Eocene strata and two from Oligocene strata in western North
America. To this record of fossil forms we add the occurrence of a species from beds of Pliocene
age in San Diego. Five species of Balanophyllia are known to occur at the present time in west
American marine waters between British Columbia and Ecuador.

(27) Dendrophyllia oldroydi Faustino?, Durham, Jour. Paleo., Vol. 17, No. 2, p. 201, pl. 32, fig. 1, March, 1943. “Loc.
A3770, late Pliocene or Pleistocene of Humboldt County, California. Exposed in road cut along U. S. Highway 101, 1.5 miles
north of bridge across Little River at Little River Beach State Park, from a highly fossiliferous gravel lense in loose sand.”

(28) Dendrophyllia californica Durham, Geol. Soc. America, Mem. 20, p. 37, pl. 10, figs. 2, 6, March 26, 1947. “27°52' N.
Lat., 114°54'45” W. Long. Taken on a rock cod line in 23 fms.”

(29) Dendrophyllia cortezi Durham and Barnard, Allan Hancock Pac. Exped., Vol. 16, No. 1, p. 102, pl. 16, figs. 66a,
66b, August 18, 1952.

84 San Dreco Sociery oF Naturat History [Memoirs

Balanophyllia elegans Verrill
Plate 19, Figures 14, 19-21; Plate 24, Figures 4, 5, 8, 13, 15-17

Balanophyllia elegans Verrill, Bull. Mus. Comp. Zool., Vol. 1, No. 3, p. 44, January, 1864.—Verrill, Trans. Connecticut Acad.
Arts and Sci., Vol. 1, pp. 511-512, pl. 10, fig. 3, 1870. Puget Sound to Monterey, California, Recent—Durham, Geol.
Soc. America, Mem. 20, p. 41, pl. 1, figs. 7, 8, 11, 12; pl. 10, figs. 3, 4, text fig. 2A, 1947. British Columbia to Point Con-
ception and the Channel Islands, California, low tide to 160 fathoms, Recent—Durham and Barnard, Allan Hancock Pac.
Exped., Vol. 16, No. 1, p. 99, pl. 14, figs. 62a-c, 1952. British Columbia to northwest of Cortes Bank, west of San Diego,
California, in 36-321 fathoms, Recent.

TYPE SPECIMEN: Location unknown to the present authors.
Type Locatity: “Crescent City and Mendocino, California; A. Agassiz.”

RaNnGE: Middle Pliocene to Recent. Recent from British Columbia, Canada, to Punta Santo
Tomas”, Lower California, Mexico, intertidal zone to 587 meters (321 fathoms), but usually
abundant in less than 91 meters (50 fathoms).

OccuRRENCE IN THE SAN DrEGO FORMATION: Los ANGELES County Museum: Loc. 305, 2400 feet east and 1350
feet south of the northwest corner of Sec. 8, T.19S., R. 2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topo-
graphic map, San Ysidro quadrangle, ed. 1943). UNiversity oF CattForniA: Loc. A-8333, same locality as the preceding.

ORIGINAL DESCRIPTION: Corallum attached by a broad base, low, subturbinate. Calyx broad,
oval, deep. Epitheca well developed, covering more than half the height of the wall, which is thin and
very porous. Septa thin, forming five complete cycles, the principle ones a little exsert, strongly toothed
at the summit, finely dentate below; those of the last order unite together near the columella, and are
joined near their middle by those of the preceding order; columella porous, little developed. Height,

.4 of an inch; greatest diameter of the calyx .48, shortest .4. Color of the living polyp, bright orange.
(Verrill.)

Remarks: Several hundred specimens referable to this species were collected by G. P. Kanakoff
at Loc. 305 (LAM), near the Mexican boundary in southwestern San Diego County. The largest
is about 20.8 mm. high with a calice 7 mm. in greatest diameter. These are all referable to the Recent
species, Balanophyllia elegans. Five specimens, the largest 16 mm. in altitude and approximately 7 mm.
in diameter, were collected by W. K. Emerson at the same locality (UC A-8333).

Durham (1947, p. 41) mentioned that northern littoral specimens of this species have nearly
smooth septa but that the more southern forms in the same habitat have the septa ornamented with
coarse granules. He further stated that specimens from deep water are thinner and more fragile, with
the epitheca usually not well developed. Durham expressed the opinion (oral communication) that the
elongate form of the present specimens might suggest that they lived at depths possibly between 46 and
366 meters (25 and 200 fathoms). Other fossils accompanying these corals suggest that the assemblage
lived in comparatively shallow water.

Balanophyllia cedrosensis Durham (1947, p. 40, pl. 11, figs. 3, 5; text fig. 2B), described from near
Cedros Island, was said to differ “from B. elegans by the greater constriction above the base, by its
greater size, larger raised columella, and by the inner edges of all except the first two cycles of septa
on B, elegans being markedly dentate. On B. elegans the septa slope to the floor of the calice, and
the columella is not raised.”

Vaughan and Wells (1943, p. 86) pointed out the close relationship between Balanophyllia elegans

in the western Americas and B. regia Gosse in British waters, B. verrucaria Linnaeus") in the Mediter-
ranean, and B. capensis Verrill°”) in South Africa.

(30) Recorded by W. K. Emerson, Jour. Paleo., Vol. 30, No. 2, p. 394, March, 1956.

(31) Madrepora verrucaria Linnaeus, Syst. Nat., ed. 10, p. 793, 1758. “Habitat in M. Mediterraneo.”—Milne Edwards
and Haime, Ann. Sci. Nat., Ser. 3, Vol. 10, p. 85, pl. 1, figs. 6, 6a, August, 1848 (as Balanophyllia verrucaria). “Habite la
Corse.” —Milne Edwards and Haime, Hist. Nat. Corall., Vol. 3, p. 100, 1860 (as Balanophyllia verrucaria). “Habite la Corse.”
{The name of this species was erroneously cited as “verrucosa” by Vaughan and Wells}.

(32) Balanophyllia capensis Verrill, Commun. Essex Inst., Vol. 5, p. 28, pl. 1, fig. 1; pl. 2, figs. 1, la, 1866. From Simon’s
Bay, Cape of Good Hope, 15 to 20 fathoms.

VotumeE II] Marine PLioceNE OF SAN D1kGo, CALIFORNIA 85

Phylum BRYOZOA Ehrenberg
A modern classification of this phylum by Bassler'’’) appeared recently. Earlier, Canu and
Bassler*) published a report on late Tertiary and Quaternary Bryozoa of North America.

A number of specimens of Bryozoa were mounted on glass slides by W. D. Rankin during the
segregation of foraminifera found in Pliocene strata at Pacific Beach, San Diego. These specimens
were submitted to Dr. R. C. Bassler, Head Curator of the Department of Geology, United States
National Museum, who kindly identified nine species. Dr. Bassler also identified, as to genus only,
Hippodiplosia and Membranipora collected by the late E. H. Quayle.

Specimens of Bryozoa collected recently by George P. Kanakoff of the Los Angeles County
Museum, from Pliocene strata in and near San Diego, were identified by Dr. John D. Soule, Allan
Hancock Foundation, University of Southern California. He also studied the material which formed
the basis of Bassler’s list, finding one additional species, Parasmittina trispinosa (Johnston).

Table 1 lists the Pliocene species of Bryozoa from San Diego, as identified by Bassler and by
Soule, the nomenclature according to Soule.

Dr. Soule’s comments on this assemblage are summarized as follows.

Of the 31 species thus far definitely identified from the San Diego Pliocene, only three are not
known in Recent waters. These are Cheilopora grandis Canu and Bassler, previously reported from the
Eocene, and Smittina discoidea Canu and Bassler and Stathmepora flabellata Canu and Bassler, both
previously listed only from the Pleistocene’). Of the remaining 28 species, so far as I know, only
the following nine have previously been listed from the Pliocene:

Adeona violacea (Johnston) Microporella ciliata (Pallas)

Chapperia patula (Hincks) Parasmittina trispinosa (Johnston)
Colletosia radiata (Moll) Porella porifera (Hincks)

Hippoporella gorgonensis Hastings Schizoporella cornuta (Gabb and Horn)

Hippothoa hyalina (Linnaeus)

Of these nine only Adeona violacea (Johnston), found in present-day tropical waters, is not listed
from the Pleistocene — unless the listing of Adeona heckelii Reuss refers to this species. (Canu and
Bassler considered A. violacea a junior synonym of A. heckelii; but both Osborne and I disagree with
this conclusion. )

The bathymetric ranges of the 28 Recent species are between low water and 490 meters (268
fathoms), most species occurring in less than 275 meters (150 fathoms).

The Pacific coast of North America south of the polar regions may be divided into three zoo-
geographical zones: (1) a cool temperate zone from Alaska to Point Conception, California, (2) a
warm temperate zone from Point Conception to Magdalena Bay, Lower California, and (3) a tropic
zone from Magdalena Bay to about 6° South Latitude. The 28 species of Bryozoa reported from the
San Diego Pliocene and still extant have the following zonal distribution:

Hippothoa hyalina and Parasmittina trispinosa are truly cosmopolitan: they are found in abundance
from the polar regions to tropical waters in both the Atlantic and the Pacific. Three species are exclu-
sively tropical. Nine are tropical, warm temperate, and cool temperate. Ten are only warm and cool
temperate. None are only cool temperate or polar. Thus the Pliocene Bryozoan fauna of San Diego
appears to have been predominately warm temperate to tropical.

(33) Bassler, R. S., “Bryozoa,” [in] Treatise on Invertebrate Paleontology, (Geol. Soc. America and Univ. Kansas Press),
Part G, pp. G1-G253, figs. 1-175, 1953.

G4) Canu, F., and Bassler, R. S., “North American Later Tertiary and Quaternary Bryozoa,” U. S. Nat. Mus., Bull.
125, pp. ivii, 1-302, figs. 1-38, pls. 1-47, July 16, 1923.

(35) See Soule, J. D., and Duff, M. M., “Fossil Bryozoa from the Pleistocene of Southern California,’ Proc. Calif. Acad.
Sci., Ser. 4, Vol. 29, No. 4, pp. 87-146, November 5, 1957.

86 San Dreco Socrery oF NaturaL History

TABLE 1. PLIOCENE SPECIES OF BRYOZOA FROM SAN D1EGO

[ Memorrs

eee ee ese eee

Adeona violacea (Johnston), 1847

Callopora corniculifera (Hincks), 1882
Cellaria diffusa Robertson, 1905 .

Cellaria mandibulata Hincks, 1882

Chapperia patula (Hincks), 1881

Cheilopora grandis Canu and Bassler, 1920 .
Coleopora gigantea (Canu and Bassler) , 1923
Colletosia radiata (Moll) , 1803 :
Conopeum commensale Kirkpatrick and Metzelaar, 1922
Crisia serrulata Osburn, 1953

Diaperoecia californica (d’Orbigny) , 1852
Disporella californica (d’Orbigny), 1852
Eurystomella bilabiata (Hincks), 1882
Heteropora pacifica Borg, 1933

Hippodiplosia sp.

Hippopodinella ee (Busk), 1854
Hippoporella gorgonensis Hastings, 1930
Hippothoa hyalina (Linnaeus) , 1767
Lagenipora punctulata (Gabb and Horn), 1862
Membranipora sp.

Microporella californica (Buck), 1856 .
Microporella ciliata (Pallas), 1766
Microporella umbonata (Hincks) , 1884
Mucronella major (Hincks) , 1884
Parasmittina trispinosa (Johnston), 1825
Penetrantia sp.) :

Porella porifera (Hincks) , 1884

Reginella mucronata (Canu and Bassler), 1923
Rhynchozoon rostratum (Busk), 1856 .
Schizoporella cornuta (Gabb and Horn), 1862
Smittina discoidea Canu and Bassler, 1923 .
Stathmepora flabellata Canu and Bassler, 1923
Thalamoporella californica (Levinsen) , 1909
Tubulipora tuba Se and ae): 1862

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(36) This ery of a ctenostome Bapcacail is based upon galleries riddling fragments of shells to which Bryozoa are

attached.

Votume II] Marine PLIocENE OF SAN Dreco, CALIFORNIA 87

The Bryozoa recorded in the present paper are from the following localities.
CALIFORNIA ACADEMY OF SCIENCES: Pacific Beach; W. D. Rankin, collector.
Los ANGELES County Museum:

Locatity 107.— 100-foot bluff with scattered concretions, in the clay quarry at the end of
Arroyo Drive, San Diego; G. P. Kanakoff, collector.

Locatity 122.— 20 to 30 feet below the end of Loring Street, Pacific Beach.

Locatity 305. — 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T.19S,
R. 2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topographic map, San Ysidro
quadrangle, ed. 1943); G. P. Kanakoff, collector.

San Disco Society oF Natura History:

Locatity 414.— Coarse conglomerate layer with a limy matrix, barnacle reef in the first road
cut on Euclid Avenue south of University Avenue, where the road curves to the left as it enters Las
Chollas Valley, San Diego; E. H. Quayle, collector. [== Loc. 308 (UCLA). }

Locatity 415.— Oyster layer in a building excavation at the southeast corner of India and Upas
streets, San Diego; E. H. Quayle, collector. [=-Loc. 309 (UCLA). ]

Locauity 417.— The second ravine north of Loc. 331 (SD) and the fifth ravine north (about
V4 mile north) of the Mexican boundary, at west face of terrace 34 mile east of coast, the ravine
debouching near the north end of a willow patch. Lower conglomerate well consolidated and richly

fossiliferous; E. H. Quayle, collector. [== Loc. 312 (UCLA).}

88 San Dreco Society oF Natura History [Memorrs

Phylum BRACHIOPODA Dumeéril

Brachiopoda are known to occur from early Cambrian to Recent. They are primarily shallow-
water dwellers, becoming less abundant in deeper water, but they have been recorded from a depth of
5,477 meters (2,995 fathoms). The largest number of species live in the warmer seas.

The west American Cenozoic Brachiopoda have been discussed and illustrated in a monograph
by the present authors”), where references may be found (p. 10) to many of the important works
dealing with their classification, morphology, and distribution. The west American Pliocene forms
were classified in 3 orders, 5 families, 7 genera, and 20 species and subspecies. Five species and sub-
species are represented in the Pliocene strata at San Diego. Many of the late Cenozoic species in
western North America are represented by closely related forms in beds of approximately the same
age in Japan®®).

Mattox? recently discussed the ecologic occurrences of brachiopod communities in the waters
about Santa Catalina Island off southern California.

Class INARTICULATA Huxley
Order ATREMATA Beecher
Superfamily LINGULACEA Waagen"”

Family LINGULIDAE Gray

Attenuate, sub-quadrate or spatulate, almost equivalved Lingulacea, with a more or less long,
tubular, flexible pedicle. Muscles highly differentiated and consisting of six pairs, two adductors, and
four of sliders or adjustors. (Schuchert in Eastman’s ed. of Zittel’s text-book of Paleo., 1913.)
Ordovician to Recent.

Genus GLOTTIDIA Dall

Glottidia Dall, Amer. Jour. Conch., Vol. 6, Pt. 2, p. 157, October 6, 1870. “Type. Glottidia albida, Dall. Pl. 8, fig. 1-6.”—
Thomson, New Zealand Board Sci. and Art, Manual No. 7, p. 128, 1927. “Genotype.—Lingula albida Hinds,” fig. 36
(a, b).—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 10, November 4, 1944. “Type
of the genus (by original designation).—Glottidia albida Hinds.”

Tyee species (by original designation) : Glottidia albida Hinds.
RANGE: Late Eocene to Recent. Recent in western America from Monterey Bay, California, to
Peru. Also Caribbean.

ORIGINAL DESCRIPTION: Shell linguiform, elongate, pedunculated; general characters as in
Lingula. Neural valve provided internally with two sharp narrow incurved laminae, diverging from
the beak and extending about one-third the length of the shell; anterior extremities of the laminae about

(37) Hertlein, L. G., and Grant, U. S., IV, “The Cenozoic Brachiopoda of Western North America,” Publ. Univ. Calif.
Los Angeles Math. Phys. Sci., Vol. 3, pp. i-vi, 1-236, figs. 1-34, pls. 1-21, November 4, 1944.

Two later American works dealing with the Brachiopoda as a whole but with emphasis on classification, morphology, and
distribution are: Cooper, G. A., [in] “Index Fossils of North America” by Shimer, H. W., and Shrock, R. R., (John Wiley &
Sons, Inc., New York), Brachiopoda, pp. 277-365, pls. 105-143, 1944; Moore, R. C., Lalicker, C. G., and Fischer, A. G.,
“Invertebrate Fossils,’ (McGraw-Hill Book Co., Inc., New York), Brachiopoda, pp. 197-267, fig. 6(1-40), 1952.

(38) See Hatai, K. M., “The Cenozoic Brachiopoda of Japan,” Sci. Repts. Tohoku Imper. Univ., Sendai, Japan, Ser. 2
(Geol.), Vol. 20, pp. 1-413, pls. 1-12, figs. 1-25, in text, 1940.

(39) Mattox, N., “Observations on the Brachiopod Communities near Santa Catalina Island,” Essays in the Natural Sciences
in Honor of Captain Allan Hancock on the Occasion of his Birthday July 26, 1955 (Univ. South. Calif. Press, Los Angeles),
pp. 73-86, figs. 1-5, November 8, 1955.

(40) Cited as “Superfamily 2. Lingulacea. Waagen” by Schuchert in Eastman’s edit. of Zittel’s Text-Book of Palaeo., Vol. 1,
p. 306, 1896. Waagen (Palaeo. Indica, Ser. 13, Vol. 1, Pt. 4, Fasc. 5, 1885) stated (p. 751), “a suborder for which I shall
introduce the name of ‘Lingulacea’ or ‘Mesokaulia’.” P. 754, “Sub-Order: Mesokaulia sive Lingulacea.” There is also a
“Division” Lingulaceae of Bowditch, 1822, and “Fam. 1. Lingulacea” of Menke, 1830.

VotumeE II] Marine PLIOCENE OF SAN DiEco, CALIFORNIA 89

midway between the mesial line and the margin. Haemal valve with a mesial septum of about the same
length extending forward from the beak. Anterior adductor impression rounded, separated by a faint
mesial ridge, faintly impressed. Scar of the post adductor close in the cavity of the beak, rounded. No
other evident scars. Shell smooth, perforate or imperforate. (Dall.)

RemarKs: We can add nothing to Morse’s*") remarks concerning the distinction between Glot-
tidia and Lingula which follow:

“Aside from the internal structure of the dorsal and ventral shell, the form of the protegulum, the presence
of gill ampullae, the arrangement of the oblique muscles, and the more anterior position of the coelomic cavity,
I found that in Glottidia the setal tubes were not formed, though the lateral setae assume a vertical position when
partially buried in the sand, as in L. lepidula; the sand tube is much more complete and symmetrical and in
alcohol is retained on the peduncle, while in L. lepidula the sand tube becomes detached. In general behavior,
however, the two forms are almost precisely alike. Charles Schuchert (’97), in considering the enormous period
in geological history occupied by the Lingulidae, says the only change observable is that in the ancient forms the
viscera occupy a little more and the brachia a somewhat less space than in the later forms. Glottidia by these
characters is a more ancient type.”

Glottidia, so far as known, is confined to the two sides of the Americas. It is known to occur
from late Eocene to Recent in the eastern Pacific and from Miocene to Recent in the western Atlantic.
Four species have been described living in west American waters and one in the Caribbean. Only one

species has been recorded from beds of Pliocene age in western North America.

Schuchert mentioned that inarticulate Brachiopoda of shallow and littoral zones are found in
comparatively warm water. The maximum depth at which Glottidia has been reported is 110 meters
(60 fathoms); but as stated by Schuchert, “the immediate shoreline, and often the estuarine bays and
deltas, will be indicated especially by the large lingulids embedded in muds and sands with an otherwise
sparse fauna.” They are therefore generally considered indicators of shorelines. Morse pointed out
that the empty shells of Glottidia are delicate and light and unless covered by sediment are likely to be
carried away by even a slight current.

Glottidia albida Hinds
Plate 19, Figures 17, 18, 23-25

Lingula albida Hinds, Voy. Sulphur, Zool., Moll., Pt. 3, p. 71, pl. 19, fig. 4, 1844 (date cited as January, 1845 on cover of
No. 8, Moll., Pt. 3).—Cooper, Calif. State Mining Bureau, 7th Ann. Rept. State Mineralogist, p. 246, 1888. “San Diego
well,” Pliocene.

Glottidia albida Hinds, Dall, Proc. Calif. Acad. Sci., Vol. 5, p. 296, 1874. “Well at San Diego.” “Pliocene.”—Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 94, 1903. “San Diego well (Hemphill) ,” Pliocene-—Hertlein and Grant, Mem. San Diego
Soc. Nat. Hist., Vol. 2, p. 48, Dall’s record of well at San Diego; p. 59, “excavations along India Street, particularly at
the corner of Upas Street,” 1944.—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 12,
pl. 1, fig. 5 (San Diego, Recent), 6 (reproduction of original figure), 7 (Redondo Beach, Calif., Recent), text figs. la-lc
(Recent), 1944. Page 14, “San Diego well”; “India and Upas streets”; “Soledad Mountain,” Pliocene. Also cited from

other localities in and near San Diego.

Type specimen”): [?} No. ZB.1, Department of Paleontology, British Museum (Natural
History).

Type tocauity: “Bay of Magdalena, [Lower] California. In seven fathoms, among sandy
mud.”

Rance: ?Late Eocene to Recent. Recent from Monterey Bay, California, to Acapulco Bay,

Mexico, from the intertidal zone to 110 meters (60 fathoms) or perhaps to 146 meters (80 fathoms).

OccuRRENCE IN THE SAN DrEGO FORMATION: San Diego well, Balboa Park (Dall; Cooper; Arnold; Hertlein and
Grant). CaLiForNIA ACADEMY OF ScIENCES: Loc. 957, upper beds of Pliocene section, 5 to 15 feet beneath overlying Pleisto-
cene at Pacific Beach; Loc. 1181, gulch on south slope of Soledad Mountain about V3, mile west of Rose Canyon; Loc. 1399, in

(41) Morse, E. S., “Observations on Living Brachiopods,’” Mem. Boston Soc. Nat. Hist., Vol. 5, No. 8, pp. 313-386, pls.
39-61, 1902 (see especially p. 317).

(42) Dr. Helen M. Muir-Wood of the British Museum (Natural History), Department of Paleontology, furnished us the
following information pertaining to the type specimen of this species. “The type specimen of Glottidia albida (Hinds) is more
difficult since there is nothing in the ‘Voyage of the Sulphur’ Report to indicate where the figured specimen is located. Hinds
mentioned that he had used the Cuming collection specimens in preparing his report and it seems probable that the Cuming speci-
men which was figured by Reeve, Conch. Icon. vol. 13, Mon. Lingula, 1862, plate 1, fig. 4, may be the same as Hinds’ speci-
men. The pedicle in this specimen is no longer preserved and the two valves have been separated at some earlier date and attached
in a rather broken condition to cardboard. Cuming’s specimen corresponds quite well in size with Hinds’ figure. There is no label
with this specimen to show whether it was used by Hinds or not. The number of this specimen preserved in the Department of
Paleontology is ZB.1.”

90 San Dieco Society oF Natrurat History [Memoirs

bluff 100 to 200 yards south of Eocene-Pliocene contact at Pacific Beach; Loc. 1401, first canyon west of Rose Canyon on south
slope of Soledad Mountain; Loc. 28880, road cut 0.1 mile east of Euclid Avenue on north side of Market Street, in Las Chollas
Valley, San Diego; Loc. 28893, corner of India and Upas streets, San Diego. Los ANGELES County Museum: About 50
feet northeast from north end of quarry at Loc. 107 [=clay quarry at end of Arroyo Drive]; Loc. 305, 2400 feet east and
1350 feet south of northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topo-
graphic map, San Ysidro quadrangle, ed. 1943). San Dieco Society or Natura History: Loc. 5, south slope of Soledad
Mountain, same locality as Loc. 1181 (CAS); Loc. 34, northeast corner of India and Thorn streets, San Diego; Loc. 80, south
slope of Soledad Mountain, same locality as Loc. 1181 (CAS); Loc. 417, fifth ravine north of Mexican boundary, about 1/4 mile
north of boundary, at west face of terrace about 34 mile east of coast. UNIVERSITY OF CALIFORNIA AT Los ANGELES: Loc. 296,
street cut on northwest side of Fairmount Avenue, 0.4 mile north of intersection with Broadway, San Diego [—Loc. 400 (SD) };
Loc. 302 [=Loc. 28880 (CAS); Loc. 408 (SD)]; Loc. 309, oyster bed in building excavation at southeast corner of India
and Upas streets, San Diego [=Loc. 415 (SD) ]}; Loc. 312, second ravine north of Loc. 294 (UCLA), and fifth ravine north of
Mexican boundary, about 34 mile east of coast, ravine debouching near north end of willow patch [—Loc. 417 (SD) ]; Loc.
2359, south slope of Soledad Mountain, in soft fine-grained sandstone outcropping in small canyon parallel to and about 0.2 mile

west of mouth of Rose Canyon and 0.4 mile north of Garnet Avenue. This locality is 2.6 miles S.40°E. of triangulation station
on Soledad Mountain.

ORIGINAL DESCRIPTION: Testa oblonga, laevi, complanata, anticé truncata, ubique albida; pedi-
culo brevi, cylindraceo. (Hinds.)

Remarks: Glottidia albida is easily recognized by its elongate boat-shaped form and thin, smooth,
shiny, yellowish or cream-colored shell. Recent specimens are sometimes ornamented with brown
streaks along the sides of the shell.

Specimens of this small brachiopod, often about 15 to 20 mm. in length, occur at many localities
in the San Diego formation. Perfect specimens, however, are not easily recovered because of the
fragile nature of the shell. Excellent specimens, the largest approximately 20 mm. in length and
9.5 mm. in width, were collected by J. F. Arndt about 50 feet northeast of Loc. 107 (LAM).

The shell is less pointed posteriorly and the internal laminae are more divergent in this species
than in Glottidia palmeri Dall), which occurs in the Gulf of California. The shell of Glottidia
audebarti Broderip" also is more pointed posteriorly than that of G. albida, and in Recent specimens
the distal half is colored bright green. Juvenile specimens of Glottidia albida are somewhat similar to
those of Glottidia semen Broderip’. Judging front the description and illustrations, it appears that
the shell of G. semen is smaller and thicker and the anterior end is straighter in outline.

Specimens from well cores from Pliocene strata in San Joaquin County, California, have been
referred by us to the present species. Some of these have the posterior end somewhat more pointed than
that of typical Glottidia albida, but this may be due to imperfect preservation. An imperfect specimen
from a well core from the lower portion of the Kreyenhagen formation of late Eocene age in Fresno
County, California, was questionably referred to G. albida by the present authors, but perfect speci-
mens from beds of that age may show differences from Recent specimens.

Woodring‘ mentioned the rare occurrence of “Glottidia cf. G. albida (Hinds)” in the Cebada
member of the Careaga sandstone in the Santa Maria district in southern California. Many species
in the associated fauna also occur with Glottidia albida in the Pliocene beds at San Diego.

Glottidia albida is an inhabitant of fine sand and mud bottoms, where it affixes itself by its pedicle.
It appears to be somewhat tolerant of salinity, and it usually does not occur in coarse sand or in the
densest muds. It has been recorded as occurring from intertidal flats to a depth of 110 meters (60
fathoms) and perhaps 146 meters (80 fathoms). Mattox (1955) recorded it from depths of 15, 27,
and 82 meters (8, 15, and 45 fathoms) on sandy bottoms around Santa Catalina Island, California.

(43) Glottidia (?albida var.) palmeri Dall, Amer. Jour. Conch., Vol. 7, Pt. 2, p. 77, November 2, 1871. “Habitat at
the head of the Gulf of California on the Lower California side, opposite the mouth of the Colorado River; in sandy shelly mud
at low water mark.’—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 17, pl. 1, fig. 10, text
fig. 2, 1944. Earlier records cited. Gulf of California.

(44) Lingula audebardii Broderip, Proc. Zool. Soc. London for 1833, p. 125, March 12, 1834. “Hab. ad Insulam Punam.
(Bay of Guayaquil).” “Mr. Cuming found this species, at about half-tide, in an extensive bottom of hard coarse sand, from four
to six inches below its surface.”—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 16, pl. 1,
figs. 2-4, 1944. Earlier records cited. Lower California to Peru (as Glottidia audebarti).

(45) Lingula semen Broderip, Proc. Zool. Soc. London for 1833, p. 125, March 12, 1834. “Hab. ad Insulam Platam
Columbiae Occidentalis.” “Dredged by Mr. Cuming in fine coral sand from a depth of seventeen fathoms.”—Hertlein and Grant,
Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 20, pl. 1, fig. 1, 1944 (as Glottidia semen). Earlier records cited.

(46) Woodring, W. P., in Woodring, W.P., and Bramlette, M. N., “Geology and Paleontology of the Santa Maria
District California,’ U.S. Geol. Surv., Prof. Paper 222, pp. 48 (insert), 62, 1951.

VotumeE II] MariINE PLIOCENE OF SAN D1EGO, CALIFORNIA 91

He mentioned that it did not occur commonly, but he suggested that it may occur in colonies because
one bottom sample from 82 meters (45 fathoms) contained 43 individuals in an area of two square feet.

Class ARTICULATA Huxley
Order TELOTREMATA Beecher
Superfamily TEREBRATULACEA Waagen“”’

Family TEREBRATELLIDAE King

Terebratulacea in which the lophophore up to the schizolophus stage has the cirri directed inwardly.
The primary invagination of the lophophore in the schizolophus stage is occupied by a median septum.
The loop in the higher genera develops both from the cardinalia and the median septum, but may
ultimately free itself from the latter, and the septum may be partly or wholly resorbed. (Thompson,
1927.) Jurassic to Recent.

Elliott) recently discussed the geological distribution and the origin of the Terebratelloid
Brachiopoda.

KEY TO THE GENERA OF TEREBRATELLIDAE

A. Generally wider than long; sulcate; generally multiplicate or smooth; foramen large....................-. Terebratalia
B. Generally longer than wide; anterior margin straight or with a slight sulcus;
STOLL COALSE LY DUNICta Ces tO LALIT SC a eee ates eee enna en re eee ee Laqueus

Genus TEREBRATALIA Beecher

Terebratalia Beecher, Trans. Connecticut Acad. Arts and Sci., Vol. 9, Pt. 2, p. 377, 1893. “Type. Terebratula transversa
G. B. Sowerby.” —Thomson, New Zealand Board Sci. and Art, Manual No. 7, p. 245, 1927. “Genotype. —Terebratula
transversa Sowerby.” —Hatai, Sci. Repts. Tohoku Imper. Univ., Sendai, Japan, Ser. 2 (Geol.), Vol. 20, p. 275, 1940.
“Genotype: —Terebratula transyersa Sowerby.” —Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci.,
Vol. 3, p. 117, 1944. “Type of the genus (by original designation). —Terebratula transversa Sowerby.”

Type SPECIES (by original designation) : Terebratula transversa G. B. Sowerby [Proc. Zool. Soc.
London for 1846, p. 94. No locality cited. —Hertlein and Grant, Publ. Univ. Calif. Los Angeles
Math. Phys. Sci., Vol. 3, p. 135, pl. 8, figs. 10, 15, 16; pl. 9, figs. 1, 2, 5-7; pl. 21, figs. 8, 9, 1944 (as
Terebratalia transversa). Earlier records cited, Miocene to Recent. Recent from the Shumagin Islands,

Alaska, to Ensenada, Lower California, Mexico. }

Rance: Oligocene to Recent from Japan to Lower California, Mexico. Recent in splash pools
above high tide and at depths of 1463 meters (800 fathoms), but most of the species live at depths less
than 183 meters (100 fathoms).

DescripTIon: Shell large, generally wider than long, sulcate, test smooth or more generally multi-
plicate. Beak short, suberect, beak-ridges sharp, with planareas on each side, foramen large, mesothyrid,
attrite and generally much worn, incomplete or occasionally complete. Hinge-teeth supported by dental
plates, which are small, recessive ventrally, and sometimes almost obsolete, pedicle-collar short, sessile.
Cardinalia strong, somewhat variable, characterized by a callous deposit between the socket-ridges in
the umbonal region, with which the septum unites; the crural bases are closely applied to the socket-
ridges in the type species, and run back to join the callous deposit, but in other species are separated
from the socket-ridges by partially excavate external hinge-plates, or may be much swollen. Cardinal
process variable in size, fused with the callous deposit. Septum generally stout, but very low posteriorly.
Loop generally with a narrow ribbon, long, reflected, and united to the septum by a narrow connecting

(47) Cited as “Superfamily 2. Terebratulacea Waagen” by Schuchert in Eastman’s edit. of Zittel’s Text-Book of Palaeo., Vol.
1, p. 325, 1896. Waagen (Palaeo. Indica, Ser. 13, Vol. 1, Pt. 4, Fasc. 2, p. 447, 1883) proposed the “Sub-Order: Kampylo-
pegmata, sive Terebratulacea, comprising the families: Terebratulidae, Thecideidae, Rynchonellidae, and Stringocephalidae.” There
is also “Fam. 2. Terebratulacea” of Menke, 1830.

(48) Elliott, G. F., “On the Geographical Distribution of Terebratelloid Brachiopods,” Ann. and Mag. Nat. Hist., Ser. 12,
Vol. 4, No. 40, pp. 305-334, figs. 1-5, 1951; “The origin of the Terebratellacea (Brachiopoda),”’ Ann. and Mag. Nat. Hist.,
Ser. 12, Vol. 10, No. 112, pp. 259-264, April, 1957.

92 San Dreco Society oF Natura History [Memoirs

band from the descending branches. The pedicle is short, and the foraminal edges and sometimes the
dorsal umbo are generally much abraded. (Thomson, 1927.)

Remarks: Thirteen species and subspecies of this genus were cited in our earlier paper (1944)
as occurring in the Cenozoic of the northeast Pacific. Hatai (1940) cited ten species from the Cenozoic
of Japan.

KEY TO THE SPECIES OF TEREBRATALIA
A. Mesial flexure on the pedicle valve concave, on the brachial valve convex
a. Mesial flexure usually pronounced; ribs about 9 on typical form

(occasionally ‘asimatiy.asi24)) 28ers occidentalis
aa. Mesial flexure usually very weak; ribs about 40 on typical form.............--2--:scessescocceseeeeeeeeeeeeeeeeeee arnoldi
B. Méesial flexure on the pedicle valve convex, on the brachial valve concave...........--..-:.--s+--+-s0ssoeeceesoeeeo-s hemphilli

Terebratalia arnoldi Hertlein and Grant

Plate 19, Figure 30

Terebratalia smithi Arnold, J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 3, p. 170, 1912. “San Diego-Purisima.” —J. P.
Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, pp. 150, 151, 1919. “San Diego,” Pliocene. —Hertlein and Grant,
Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 133, 1944. “Pacific Beach, San Diego, between 100 and 200
meters south of the Eocene-Pliocene contact.” Record by J. P. Smith also cited.

Not Terebratalia smithi Arnold, 1903.

Terebratalia arnoldi Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 119, pl. 11, figs. 1-3, 10-15,
November 4, 1944.

TYPE SPECIMEN: No. 7313, Type Collection, Department of Geology, California Academy of
Sciences.

Type Locatity: “From Loc. 27185 (Calif. Acad. Sci.), center of SW. 14 of Sec. 23, T.3N.,
R.18W., S.B.B. & M., Ventura County, California (C. Leach, collector, December, 1931). Middle
Pliocene.”

Rance: Middle Pliocene in California.

OccurRENCE IN THE SAN DigGo FORMATION: CALIFORNIA ACADEMY OF ScrENCES: Loc. 1399, in bluffs 100 to 200
yards south of Eocene-Pliocene contact at Pacific Beach. Los ANGELES County Museum: Loc. 308, 0.2 mile north of intersec-
tion of Harbor Boulevard and Tourmaline Street, Pacific Beach.

ORIGINAL DESCRIPTION: Shell resembling Terebratalia occidentalis Dall in general shape and
ornamentation, but differing in having only a very slight development of a medial sulcus on the pedicle
valve and fold on the brachial valve. The ribs increase by bifurcation and intercalation. Along the
ventral margin of the pedicle valve of the type there are about forty ribs, but these are less in number
on small specimens. Dimensions (of holotype): length, 41 mm.; width, approximately 42.3 mm.;
convexity (of both valves), 22.4 mm. (Hertlein and Grant.)

Remarks: A pedicle valve from the lower portion of the series of strata at Pacific Beach, com-
parable to Terebratalia arnoldi, measures 41 mm. in length, 39.3 mm. in width. The mesial basal portion
of the valve is lacking, but on the remaining portion no trace of a mesial fold or sulcus is visible. The
ratio of width to length is a little less than in typical specimens of T. arnoldi, but this specimen is quite
similar to some of those of T. arnoldi from Pliocene beds in Tapo Canyon, Ventura County, California.
Radial ribbing is present although imperfectly preserved on the present specimen. The lack of a mesial
fold in this pedicle valve leads us to refer it to T. arnoldi rather than to T. smithi as was done in our
earlier paper, 1944. Two eroded valves, the larger one 23.5 mm. in height, from Loc. 308 (LAM),
are questionably referable to T. arnoldi.

Terebratalia smithi Arnold was described from strata on Deadman Island, San Pedro, California,
originally believed to be of Pliocene age but now considered by some as Pleistocene. That species has
a well-deveolped medial fold on the pedicle valve and sulcus on the brachial valve. It apparently is
closely related to Terebratalia hemphilli and T. transversa. It has been recorded from several localities
.in beds of Pliocene age, but some of these occurrences may be referable to other species.

J. P. Smith reported Terebratalia smithi from the Pliocene beds at San Diego, but in collections
from San Diego we have not seen any specimens certainly referable to that species. We are therefore

inclined to refer Smith’s record to T. arnoldi, although there is a possibility that it could refer to
T. hemphilli.

Votume II] MarINE PLIOCENE OF SAN D1EGo, CALIFORNIA 93

Terebratalia arnoldi etchegoini Hertlein and Grant'*’’, described from the Etchegoin formation,
of late Pliocene age, in the Coalinga district in the San Joaquin Valley, California, differs from the
typical form in its smaller size, its often finer ribs, and its extremely variable and often distorted shape.
This subspecies was reported recently ‘°°’ from Sonoma County, California, in beds of late Pliocene age
probably equivalent to those of the lower portion of the Merced formation at its type locality.

An incomplete valve (UCLA coll.), collected by E. H. Quayle near the corner of India and Upas
streets, San Diego, bears a faint medial sulcus similar to that of the Terebratalia arnoldi group. The
Preservation does not warrant a definite record, but, as mentioned in our earlier paper, the general
appearance is suggestive of the subspecies etchegoini.

Terebratalia arnoldi quaylei Hertlein and Grant'’’’, described from the Santa Margarita forma-
mation, late Miocene, of San Luis Obispo County, California, differs from typical T. arnoldi in the

decided development of a medial sulcus on the pedicle valve.

Some species described from beds of late Miocene and of Pliocene age in Japan'**) bear a strong
resemblance to Terebratalia arnoldi, but their identity with the California form is not certain.

Terebratalia hemphilli Dall
Plate 19, Figures 26, 27

Terebratalia hemphilli Dall, Proc. U.S. Nat. Mus., Vol. 24, No. 1264, p. 561, pl. 40, figs. 8, 10, March 31, 1902.—J. P. Smith,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, pp. 150, 151, 1919. “San Diego,” Pliocene-—Hertlein and Grant, Publ. Univ.
Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 123, pl. 9, figs. 3, 4 (copies of original figures); pl. 10, figs. 1, 2 (from
Tape Canyon, Ventura County, Pliocene), 1944. P. 124 “Market and Euclid streets, San Diego” and “Pacific Beach,”

iocene.

Terebratalia hemphillii Dall, Carson, Pan-Amer. Geol., Vol. 43, No. 4, p. 268, May, 1925. “San Diego fauna,” Pliocene.
TYPE SPECIMEN: No. 108,495, United States National Museum.

Type Locatity: “Pliocene of Santa Barbara, between one-half and 1 mile inland from the sea, in
Arroyo Buero on the Hope ranch; collected by J. Howard Wilson. U.S.N.M., 108,495.”

Rance: Middle Pliocene to late Pliocene or early Pleistocene in southern California.

OccurRENCE IN THE SAN DieGo FORMATION: San Diego, unlocalized (J. P. Smith; Carson). CaLrForNIA ACADEMY OF
Sciences: Loc. 547, Pacific Beach; Loc. 28880, road cut 0.1 mile east of Euclid Avenue on Market Street, in Las Chollas
Valley, San Diego. Los ANGELES County Museum: Loc. 122, 20 to 30 feet below end of Loring Street, Pacific Beach; Loc.
308, 0.2 mile north of intersection of Harbor Boulevard and Tourmaline Street, Pacific Beach (juvenile specimens); Loc. 311,
embankment on Windsor Drive where Tourmaline Street would intersect if projected, Pacific Beach district [—=Loc. 28884 (CAS) ].

ORIGINAL DESCRIPTION: Shell substantially as figured, thin, rather compressed or not very convex;
transverse, valves with low, flattish, ill-defined radial riblets, which, except near the beaks, become
obsolete toward the middle of the valves. Mesial flexure shallow, broad mesially concave. Area narrow,
ill-defined; foramen narrow, high, incomplete below; punctation fine and profuse. Alt. 30.0, lat. 33.0,
diam. 12.0 mm. (Dall.)

Remarks: Terebratalia hemphilli resembles T. smithi Arnold'°?) in general characters but differs
in that the mesial portions of the valves are usually smooth, only the lateral areas being radially sculp-
tured; also the shell is usually broader and the foramen smaller. The present species also is similar
to large smooth forms of Terebratalia transversa Sowerby, but it is generally larger and broader in

(49) Terebratalia arnoldi etchegoini Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 122,
pl. 10, figs. 5, 9-11, November 4, 1944. “From Loc. 189 (Southern Pacific Coll., Calif. Acad. Sci.) , 600 feet southeast of north-
west corner of Sec. 26, T.22S., R.16E., M.D.B. & M., in base of conglomerate above blue sandstone, Coalinga district, California;
Etchegoin, Pliocene.”

(50) Peck, J. H., Jr., Program of Geol. Soc. America Cordilleran Sec. Fifty-third meeting at Univ. Calif. at Los Angeles,
April 19-20, 1957, p. 31; Bull. Geol. Soc. America, Vol. 68, No. 12, Pt. 2, p. 1841, 1957.

(1) Terebratalia arnoldi quaylei Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 122,
pl. 17, figs. 1, 4, 7, November 4, 1944. “Loc. 1106 (Univ. Calif. at Los Angeles), three miles southwesterly on the south side
and up the Nacimiento River from the Nacimiento Ranch house, well towards the head of a ravine northwest of 1,108-foot hill,
in the NW 1% of the SE 1/4 of Sec. 13, T.25S., R.10E., M.D.B. & M., Bradley Quadrangle, San Luis Obispo County, California
(Mr. and Mrs. E. H. Quayle, collectors, March, 1938). Santa Margarita formation, upper Miocene. Associated with Pecten (Lyro-
pecten) estrellanus Conrad.”

(52) See Dallinella smithi Arnold, Hatai, Sci. Repts. Tohoku Imper. Univ., Sendai, Japan, Ser. 2 (Geol.), Vol. 20, p. 299,
pl. 8, figs. 39, 40, 1940. Earlier records cited, “Miocene to Pliocene.”

(53) Terebratalia smithi Arnold, Mem. Calif. Acad. Sci., Vol. 3, p. 93, pl. 17, fig. 9, 1903. “Pliocene of Deadman Island,”
San Pedro, California—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 133, pl. 10, figs. 4,
6-8, 1944. Earlier records cited. Pliocene of central and southern California.

94 San Dreco Society oF NatTuraL History [Memoirs

outline. An unusually large specimen in the collection at Stanford University measures 64 mm. in
length, 58 mm. in width, and approximately 40 mm. in convexity. There is considerable variation in
the degree of convexity or concavity as well as in the sculpture of the valves of this species.

A specimen from Loc. 28880 (CAS), on Market Street east of Euclid Avenue, San Diego, is
referable to Terebratalia hemphilli. A single incomplete, almost smooth brachial valve (pl. 19, fig. 27),
collected by Henry Hemphill from Pliocene beds at Pacific Beach appears to be referable to this
species, but it could equally well be referable to Terebratalia transversa Sowerby. A well-preserved and
only slightly imperfect pedicle valve (pl. 19, fig. 26), from Loc. 122 (LAM), Pacific Beach, bears
fine radial riblets over the entire outer surface. It is 38.9 mm. in length, 38 mm. in width, and approxi-
mately 13.4 mm. in convexity (one valve). Two juvenile specimens, apparently referable to T. hemphilli,
were collected by G. P. Kanakoff at Loc. 308 (LAM), 0.2 mile north of the intersection of Harbor
Boulevard and Tourmaline Street, Pacific Beach.

Specimens typical of this species in the collections of the University of California at Los Angeles
from Browns Canyon in the Newhall Quadrangle, Los Angeles County, are associated with typical
Pliocene mollusks that also occur in the Pliocene beds at San Diego, including Ostrea vespertina Conrad,

Pecten bellus Conrad, Pecten healeyi Arnold, and Pecten opuntia Dall.

Terebratalia occidentalis Dall
Plate 19, Figures 16, 22, 31

Terebratella occidentalis Dall, Proc. Calif. Acad. Sci., Vol. 4, Pt. 4, p. 182, pl. 1, fig. 7, January, 1872.

Terebratalia occidentalis Dall, J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 3, pp. 170, 181, 1912. “San Diego-Purisima,”
Pliocene——Gale in Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 46, 1931 [on pp. 30, 40 as Terebratalia
(or Dallinella) occidentalis}. “San Diego formation.”—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys.
Sci., Vol. 3, p. 127, pl. 10, fig. 3 (“Pacific Beach, San Diego, California, Pliocene”); pl. 17, figs. 2, 5, 8, 11, 12, and text
fig. 27 (all Recent), 1944. “Rare in lower 100-200 meters, and in the middle beds of the Pliocene at Pacific Beach, San
Diego, California; northeast corner of India and Thorn streets, San Diego, California.”

TYPE SPECIMEN: Originally No. 6 in the collection of the California State Survey. A specimen,
No. 32180 in the type collection of the University of California, Invertebrate Paleontology, is said
possibly to be the type specimen of this species. It is from Loc. 2390, ?Santa Barbara, California, a
locality not cited by Dall at the time the species was described.

Type tocauity: “Habitat, coast of California. Monterey, Cooper and Dall. Catalina Island,
Cooper. Cab. Cala. Geol. Survey No. 6.”

RANGE: Oligocene to Recent. Recent from Anacapa Island**’, California (Dall), to Cape San
Lucas, Lower California, Mexico, in 55 to 137 meters (30 to 75 fathoms).

OccurRENCE IN THE SAN DrgGO FORMATION: CALIFORNIA ACADEMY OF SCIENCES: Loc. 1399, rare in bluffs 100 to
200 yards south of Eocene-Pliocene contact at Pacific Beach; Loc. 1414, beds in middle portion of Pliocene section at Pacific
Beach; Loc. 1419, northeast corner of India and Thorn streets, San Diego; Loc. 12007, Pacific Beach; Loc. 28158, Pacific Beach
(L. M. Wright, coll.). Los ANcetes County Museum: “Old Town,” north of Five Points, San Diego (J. F. Arndt, coll.).

ORIGINAL DESCRIPTION: Shell, variable in size and shade of color, usually of a flesh tint, deeper
on some of the lines of growth. Sculptured by radiating ribs variable in number (9 in the typical
specimen), with rather smooth interspaces, only crossed by more or less prominent lines of growth.
Hinge line long, somewhat arched in the middle; area wide, sharply carinated, flat, crossed by transverse
lines of growth. Apex not prominent, usually eroded. Foramen large, incomplete, deltidia widely
separated and differentiated from the area by deep grooves. Typical specimen .75 in. long, .6 in. wide
and .2 thick. (Dall.)

Remarks: Most of the specimens of this species that we have seen from Pliocene beds at San
Diego are single valves about 28 to 30 mm. in width. They are similar to Recent specimens of Tere-
bratalia occidentalis.

The shell of this species varies considerably in sculpture; but it and members of its group are
readily distinguished from other west American species of Terebratalia by the character of the mesial

(54) This species was recorded as occurring at San Francisco, California, by Cooper and at Monterey by Cooper and Dall.
We have not seen specimens of this species from San Francisco. Concerning records of its occurrence at Monterey, California,
Smith and Gordon (Proc. Calif. Acad. Sci., Ser. 4, Vol. 26, No. 8, p. 210, 1948) stated, “These are old records that have not

been confirmed by recent collecting.”

VotumeE II] Marine PLIOCENE OF SAN Deco, CALIFORNIA 95

flexure, which is concave on the pedicle valve and convex on the brachial valve. Typical forms of this
species are sculptured with about 9 radial ribs, but occasional specimens may have as many as 24 ribs.
Some specimens are almost or entirely smooth, the smooth form being the subspecies obsoleta Dall”?.
There is complete intergradation between this form and typical T. occidentalis; but, although it may
not have great taxonomic significance, it can be retained for convenience. Fossil specimens of T. occi-
dentalis and its subspecies obsoleta attain a width of 45 mm. So far as known, Recent specimens are
smaller.

The mesial flexure on specimens of Terebratalia occidentalis from the Oligocene and early Miocene
is often rather subdued, and since this same tendency is noticeable on early members of T. transversa
Sowerby, it appears possible that the two groups, T. occidentalis and T. transversa, may have diverged
from a common stock at about this time.

Several related forms belong to the Terebratalia occidentalis group. These include T. occidentalis,
Oligocene to Recent, T. occidentalis obsoleta Dall, Miocene to Recent, T. arnoldi Hertlein and Grant,
early and middle Pliocene, T. arnoldi quaylei Hertlein and Grant, late Miocene, T. arnoldi etchegoini
Hertlein and Grant, late Pliocene, and T. jordani, Pliocene (in the Gulf of California region). All
these have been discussed and illustrated in our earlier paper, 1944. Woodring'’®) and Mattox have
questioned the distinctness of T. arnoldi from T. occidentalis, but an examination of a series of fossil
and Recent specimens leads us, at least for the present, to retain T. arnoldi as a separate species.

Most of the records of the Recent occurrences of Terebratalia occidentalis are from depths not
exceeding 91 meters (50 fathoms). According to Mattox it is the second most abundant brachiopod
in the waters about Santa Catalina Island, southern California, where it occurs singly or in small
clusters, in the ratio of about one to 100 specimens of Laqueus californianus Koch.

Genus LAQUEUS Dall

Laqueus Dall, Amer. Jour. Conch., Vol. 6, Pt. 2, p: 123, pl. 7, fig. f; pl. 8, figs. 9, 10, October 6, 1870. “Type. Laqueus califor-
nicus, Koch sp.’—Thomson, New Zealand Board Sci. and Art, Manual No. 7, p. 258, fig. 85 (a, b, c), 1927. “Genotype.
Terebratula californica Koch.”—Hatai, Sci. Repts. Tohoku Imper. Univ., Sendai, Japan, Ser. 2, (Geol.), Vol. 20, p. 343,
1940. “Genotype.—Terebratula californica Koch.”—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci.,
ae p. 143, 1944. “Type of the genus (by original designation) —Laqueus californicus Koch [=Terebratula californiana
Koch].”

Type spEctes (by original designation) : Laqueus californicus Koch [—Terebratula californiana

Koch }.

RaNnGE: Miocene to Recent, from Japan to Lower California, Mexico. Recent off western North
America in from 4 to 252 meters (2 to 138 fathoms), usually in less than 182 meters (100 fathoms).
Fragment reported by Dall from a depth of 1575 meters (861 fathoms).

Description: Shell large, ovate, hinge-line curved, biconvex rectimarginate to ligate or strangu-
late, test smooth, rather coarsely punctate, colour yellow-brown to red, sometimes with bright-red rays.
Beak fairly prominent, beak-ridges sharp, foramen small to moderate, permesothyrid, slightly remigrant,
telate, deltidial plates conjunct, concave. Hinge-teeth supported by dental plates, which are ventrally
recessive; area between dental plates slightly calloused, pedicle-collar (or a striated area) sessile, long,
but not reaching as far forward as the dental plates. Cardinalia characterized by inner and outer hinge-
plates separated by the crural bases, as in Dallina, the inner hinge-plates resting on the median septum;
no cardinal process, but a small striated area or pit over the umbo. Septum extending forward more
than one-third the length of the valve. Loop long, reflected, attached to the septum by connecting bands
as in Terebratalia, the ascending branches united to the descending branches by the interconnecting
bands on each side in the neighborhood of the connecting bands. Muscular impressions not strong.
Small spicules present over the pallial sinuses, but not extending to the body-wall or lophophore.
(Thomson, 1927.)

(55) Terebratalia occidentalis var. obsoleta Dall, Proc. U.S. Nat. Mus., Vol. 14, No. 849, p. 186, July 24, 1891. “Albatross,
station 2984, in 113 fathoms, off Cerros Island, Lower California .”—Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math.
Phys. Sci., Vol. 3, p. 131, fig. 28, pl. 12, figs. 5, 9-11, 1944 (as Terebratalia occidentalis obsoleta). Earlier records cited, Miocene
to Recent.

(56) Woodring, W. P., in Woodring, W. P., and Bramlette, M. N., “Geology and Paleontology of the Santa Maria
District,” U.S. Geol. Surv., Prof. Paper 222, p. 68, 1950.

96 San Dreco Society oF Natura History [Memoirs

Remarks: Laqueus is confined to the margins of the north and northeastern Pacific. It is known
to occur from Pliocene to Recent in California and from Miocene to Recent in Oregon, Washington,
Alaska, and Japan. Species of this genus usually occur at moderate depths on clear sea bottoms free
of mud, and a greater number occur in warm rather than cold waters.

Fourteen species were cited by Hatai as occurring in the late Cenozoic of Japan. Two species
occur at the present time in waters of the northeastern Pacific region.

KEY TO THE SPECIES OF LAQUEUS
A. Shell thin; pedicle opening small; length usually exceeding 40 mmm.........2..-..:.--s1eeeesseeceeeeeceeeeeeee californianus

B. Shell thick; pedicle opening large; length usually not exceeding 35-40 mm............... vancouveriensis diegensis

Laqueus californianus Koch
Plate 20, Figures 1-3, 5-7

Terebratula californiana Koch in Kiister, Martini-Chemnitz Conchyl_—Cab. (ed. by Kiister and Kobelr), Bd. 7, Abt. 1, Tere-
bratula, p. 38, 1848, pl. 2b, figs. 21-23, 1844.

Laqueus californianus Koch, Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 144, pl. 13, figs. 5,
8, 14; pl. 21, figs. 1-7; text fig. 31, 1944. Earlier records cited. ?Pliocene, California. Recent, British Columbia to Point
Loma, California——Mattox, Essays in Nat. Sci. in Honor of Captain Allan Hancock on the Occasion of his Birthday July
26, 1955 (Univ. South. Calif. Press), p. 75, fig. 2, November 8, 1955. Catalina Island, California, in 30 to 120 fathoms,

Recent.

TYPE SPECIMEN: Location unknown to the present authors.

Type Locatity: “Aufenthalt: in Californien.”

RanGE: Middle Pliocene, in southern California, to Recent. Recent from British Columbia to
Point Loma, California, in 46 to 549 meters (25-300 fathoms); [?} (fragment) 1575 meters (861
fathoms) (Dall.)

OccuRRENCE IN THE SAN DiEGO FORMATION: Los ANGELES County Museum: Loc. 107, 100-foot bluff with fos-
siliferous concretions in clay quarry at end of Arroyo Drive, San Diego.

ORIGINAL DESCRIPTION: T. testa maxima, ovata, ventricoso-convexa, robusta, cornea, opaca,
concentrice striata et sulcata, marginibus integris, sinuatis; rostro obtuso, incurvo; area late trigono;
foramine integro, parvo.

Muschel sehr gross, eiformig, bauchig gewolbt, starkwandig und von kraftigem Bau, horngrau,
fast glanzlos, mit feinen concentrischen Anwuchsstreifen und starkeren Furchen, kleiner Schale fast
flacher, gegen die Rander etwas gedriickt, der Oberrand schief, gegen den Wirbel ansteigend, der
Wirbel nagelformig, fast anschliessend. Auf der Flache beider Schalen zeigen sich mehrere grossere
und kleinere Eindriicke, welche sich meist als Furchen bis an den Rand fortsetzen und dort mit denen
der andern Schale zusammentreffen. Grdssere Schale starker gestreift, vorztiglich gegen den Unterrand,
der Wirbel ist wenig erhoht, stark iibergebogen, Schild breit, beiderseits durch eine fast kielformige
Erhohung abgegrianzt; Oeffnung sehr klein, rund. Hohe 27’’’, Lange 21°, Breite 15’. (Koch.)

Remarks: Several specimens collected by G. P. Kanakoff at Loc. 107 (LAM), end of Arroyo
Drive, San Diego, are referable to Laqueus californianus. Some of these are somewhat deformed by
compaction of the enclosing sediment, but the observable features are all characteristic of this species :
the shell is thin and elongate, with a small pedicle opening. They are uniformly dark brown, probably
in part because of iron stain. The largest specimen measures 41.8 mm. in length, 30 mm. in width, and
19.1 mm. in convexity (both valves together). A more rounded specimen measures 38 mm. in length,
33.5 mm. in width, and 18 mm. in convexity (both valves together).

Large specimens of the Recent form attain a length of at least 51.5 mm. Those occurring in
shallow water are red, while those in deeper water, from 55 to 110 meters (30 to 60 fathoms), tend
to be white. They often occur in colonies, some individuals attached to others. Mattox found one
cluster of 31 individuals. Also he found occasional individuals attached to Bursa californica Hinds.
He reported that in 55 to 219 meters (30 to 120 fathoms) off Catalina Island, Laqueus californianus
is about 100 times as abundant as Terebratalia occidentalis Dall, with which it often occurs.

Votume II] Marine PLIOCENE OF SAN DiEGo, CALIFORNIA 97

Records of this species in Pliocene strata are very few. Arnold”) recorded “Laqueus californicus
(or jeffreysi)” from Pliocene beds in Temescal Canyon in Los Angeles County, and Thomson (1927,
p. 259) recorded it from “Pliocene, California.”

Laqueus japonicus Yabe and Hatai'”®) bears a resemblance to L. californianus; but it is said to
differ in the thicker shell, the larger foramen, the more incurved beak, and the brownish coloration.

Under the name “Laqueus californicus convexus”, Konjukova’’™) recently described a brachiopod

with very convex valves and with a very large foramen, from Tatar Strait and the northern part of the
Sea of Japan, in 57 to 215 meters. We have not seen specimens.

Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies

Plate 20, Figures 4, 8-21

Laqueus jeffreysi Dall, Arnold, Mem. Calif. Acad. Sci., Vol. 3, p. 94, 1903. “Pliocene of Pacific Beach.”—Arnold, U.S. Geol.
Surv., Prof. Paper 47, p. 28, 1906. “San Diego formation as developed in the type section at Pacific Beach.”

Not Laqueus jeffreysi Dall, 1895.

Laqueus californicus vancouveriensis Davidson, E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, pp.
416, 426, pl. 27, fig. 7 (Cedros Island, Pliocene), 1926. “Santa Barbara and San Diego Pliocene formations of southern
California.”—Hertlein, Stanford Univ. Bull., Ser. 5, No. 78, p. 82, 1929. “San Diego Pliocene.”

Not Laqueus californicus var. vancouveriensis Davidson, 1887.

Laqueus vancouveriensis Davidson, Hertlein and Grant, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 3, p. 147, pl. 13,
figs. 6, 7, 9, 10, 1944. “Pacific Beach, San Diego, California. Pliocene.” (Not pl. 17, figs. 15-17; pl. 18, figs. 15-17, 19-21;
text fig. 32 —L. vancouveriensis Davidson).

Not Laqueus californicus var. vancouveriensis Davidson, 1887.

TYPE SPECIMEN: No. 7355 (and Paratype No. 7354), Type Collection, Department of Geology,
California Academy of Sciences. Paratypes, San Diego Society of Natural History and Los Angeles
County Museum.

TyPE Locauity: Pacific Beach, San Diego, California; Pliocene; H. Hemphill, collector. Para-
types also from Pacific Beach.

Rance: Middle Pliocene in southern California and at Cedros Island, Lower California, Mexico.

OccuRRENCE IN THE SAN DrgGO FORMATION: San Diego (Arnold; E. K. Jordan and Hertlein; Hertlein; Hertlein and
Grant). CALIFORNIA ACADEMY OF ScIENCES: Locs. 104, 537, 12005, 12006, 31356, Pacific Beach; Loc. 28884, embankment on
Windsor Drive where Tourmaline Street would intersect if projected. Los ANGELES County Museum: Loc. 122, 20 to 30
feet below end of Loring Street, Pacific Beach; Loc. 308, 0.2 mile north of intersection of Harbor Boulevard and Tourmaline
Street, Pacific Beach; Loc. 311 [—Loc. 28884 (CAS) ]; Loc. 311A, at base of recent road cut on Windsor Drive about 20 feet
toward embankment from Loc. 311 (LAM); Loc. $8439, north end of Diamond Street (Charles Sternberg, Coll.). SAN Dreco
Society oF Natrurat History: Loc. 81, south slope of Soledad Mountain; Loc. 726, Pacific Beach; Loc. 5007 {—Loc. 28884
(CAS) ]. University oF Carirornia aT Los ANGELES: Loc. 593 [=Loc. 28884 (CAS) and Loc. 726 (SD) }; Loc. 2420,
soft yellow Pliocene sands exposed in bluffs along Pacific Beach about 1/; mile southeast of False Point at foot of Law Street.

Description: Shell with general characters of Laqueus vancouveriensis Davidson but differing
in that the umbo of the pedicle valve is broader and has a larger pedicle opening, the posterior margin
of the brachial valve is more broadly rounded, and the shell is larger and thicker. Dimensions: length

34.5 mm.; width 29.5 mm.; convexity (both valves together) 21.6 mm.

Remarks: This form has been recorded from Pliocene beds in Lower California and in southern
California), at least in some instances under the name of Laqueus vancouveriensis Davidson. That
species now occurs from the Aleutian Islands, Alaska, to off Lopez Island, Puget Sound, Washington.
Comparison of many fossil specimens from San Diego with Recent specimens shows differences which
appear sufficient to justify the separation of the fossils as a subspecies.

(57) Arnold, R., “The Tertiary and Quaternary Pectens of California,’ U.S. Geol. Surv., Prof. Paper 47, p. 77, 1906. See
also U.S. Geol. Surv., Bull. 309, p. 153, 1907 (as Laqueus californicus? Koch).

(58) Laqueus japonicus Yabe and Hatai, Proc. Imper. Acad. Japan, Vol. 10, No. 10, p. 663, figs. 19-21, 26, December, 1934.
“Type loc.: Sagami Bay?.”—Hatai, Sci. Repts. Tohoku Imper. Univ., Sendai, Japan, Ser. 2 (Geol.), Vol. 20, p. 365, pl. 5,
figs. 10-19, 23-25, 1940. Miocene or Pliocene to Recent, Japan.

(58a) Konjukova, E.D., Akad. nauk SSSR, Zool Inst., Issledovaniia Dal’nevostochnikh Morei SSSR (Moskva; Leningrad),
Vol. 4, p. 53, figs. 37, 38, pl. 7, figs. 1-12, 1957.

(59) George Willett (Bull. South. Calif. Acad. Sci., Vol. 45, Pt. 1, January-April, p. 32, June 10, 1946) mentioned the

occurrence of Lagueus “vancouverensis” Davidson in strata of Pliocene age at Fourth and Broadway streets in Los Angeles,
California.

98 San Dreco Society oF Naturat History [Memoirs

This fossil form differs from the species described by Davidson” in the gross shell characters
mentioned above. The shell is decidedly thicker and attains a larger size. Dimensions of five of the
largest specimens are as follows:

Length Width Convexity
Holotype (CAS) from PacificBeach . . . . - . 34.5 mm. 29.5 mm. 21.6 mm.
Paratype (CAS) from Pacific Beach . . . . . . 33.8 mm. 31.0 mm. 20.5 mm.
Paratype (SD) from Pacific Beach. . . . . - + 30.6 mm. 24.0 mm. 20.8 mm.
Paratype (LAM) from PacificBeach . . . . . . 36.4 mm. 28.0 mm. 23.0 mm.
Hypotype (CAS) from Cedros Island. . . . - . 37.9 mm. 33.8 mm. 23.0 mm.

The largest Recent specimen of Laqueus vancouveriensis which has come to our attention is
34.5 mm. in length. This is unusual: the average length is about 25.3 mm.

Both Laqueus vancouveriensis and the new subspecies described here differ from Laqueus califor-
nianus Koch in the smaller size, thicker shell, and larger pedicle opening. Recent specimens of L. van-
couveriensis are drab or yellowish rather than pink or white as in L. californianus; and they usually
occur singly or in small groups rather than in huge colonies.

This new subspecies occurs rather abundantly in the Pacific Beach district at Loc. 28884 (CAS),
in the embankment on Windsor Drive where Tourmaline Street would intersect if projected, and at
Loc. 308 (LAM), 0.2 mile north of the intersection of Harbor Boulevard and Tourmaline Street.

(60) Laqueus californicus var. vancouveriensis Davidson, Trans. Linn. Soc. London, Ser. 2, Zool., Vol. 4, Pt. 2, p. 113, pl.
18, figs. 10-13, 13a, 13b, July, 1887. “Off Vancouver Island.” Also other localities cited. See Hertlein and Grant, 1944, p. 147,
pl. 17, figs. 15-17; pl. 18, figs. 15-17, 19-21; text fig. 32.

Dr. Helen M. Muir-Wood informed us that syntypes of this form in the Department of Paleontology, British Museum
(Natural History), illustrated by Davidson, bear the following numbers: plate 18, fig. 10 = ZB. 1611; fig. 11 = ZB.'1610; fig.
12 = ZB.1 2459; fig. 13 = ZB. 1609.

Votume II] Marine PLIOCENE OF SAN Deco, CALIFORNIA 99

Phylum ECHINODERMATA Bruguiere
Class ASTEROIDEA Burmeister .
Order PHANEROZONIA Sladen

Family ASTROPECTINIDAE Gray

Back flattish, netted with numerous tubercles, crowned with radiating spines at the tip, called
Paxilli. (Gray, 1840). Jurassic to Recent.

Genus ASTROPECTEN Linck in Gray

Astropecten Linck in Gray, Ann. and Mag. Nat. Hist., Vol. 6, No. 36, p. 180, November, 1840. Several species cited including
“Astropecten aurantiacus. Asterias aurantiaca, Linn.” —Fisher, Smithson. Miscell. Coll., Vol. 52, No. 1799, p. 93, May 27,
1908. Type: Astropecten aurantiacus Linnaeus.—Fisher, U. S. Nat. Mus., Bull. 76, Pt. 1, p. 55, June 30, 1911. Type as
indicated in 1908.

Type species (designated by Fisher, 1908, p. 93): “No type was designated by Gray; as it
is desirable to have one, A. aurantiacus‘*') (Linn.) may be so considered.” {== Asterias aranciaca
Linnaeus, Syst. Nat., ed. 10, p. 662, 1758. “Habitat in M. Mediterraneo.” Ref. to “Link. Stell.
t.4.f.14; ¢.5.£.6; t.8.f.12; t.23.£.38; t.27..44; t.36.f.63”; also others. Also illustrated by Ludwig, Fauna
und Flora des Golfes von Neapel (Berlin), Monogr. 24, pp. 3-16, pl. 2, figs. 1, 2,; pl. 6, figs. 1-5;
text fig. on p. 3, 1897 (as Astropecten aurantiacus). Mediterranean; Madeira; Bay of Setubal,
Portugal; Canary Islands. Depth, 1-183 meters. —H. L. Clark in Eastman’s ed. 2 of Zittel’s Text-Book
of Paleo., Vol. 1, p. 247, fig. 349, 1913. Recent, Mediterranean }.

RANGE: Miocene to Recent (Hess). Cosmopolitan. Species assigned to this genus by Sladen,
1889, occur at depths of 4 to 823 meters (2 to 450 fathoms), but most of them occur at depths less
than 91 meters (50 fathoms).

Description: Rays normally five in number; abactinal surface flat, not arched; actinal surface
slightly beveled on sides; disk variable in size, usually medium to small; rays usually long and tapered;
marginal plates large, the inferomarginals always broader than superomarginals and sometimes extending
laterally beyond them; inferomarginals armed with spinelets and a variable number of spines which
increase in size toward the edge of ray; superomarginals, in addition to small granules or spinelets,
may also bear tubercles or enlarged spines extending in one or two complete or interrupted rows along
ray; or enlarged spines may be entirely absent; exposed surface of consecutive marginal plates separated
by deep fasciolar grooves lined by minute capillary spinelets, these grooves acting as percolators or
filters; abactinal area covered with true paxillae; papulae single, usually absent from a narower or wider
midradial line, and from center of disk; usually six about each paxilla; actinal interradial areas typically
very small, with few paxilliform intermediate plates which do not extend far along ray, the infero-
marginals and adambulacrals being in contact on the ray proper; intermediate plates never extend
beyond middle of ray and rarely beyond proximal fourth; ambulacral plates with an angular furrow
margin, bearing typically three spines, of which the middle is slightly the longer; two or three rows of
spines on actinal surface of plates; first adambulacral plate compressed, much wider than the rest;
mouth plates narrow, the inner spines enlarged; tube feet conical, without a true sucking disk; no true
pedicillariae; anus typically absent; gonads interradial, not extending along ray; superambulacral plates
well developed. (Fisher, 1911.)

Remarks: Astropecten differs from Tritonaster Fisher in the character of the superomarginal
plates, which are not conspicuously smaller beyond the middle of the ray, and in the presence of well-
developed marginal fascioles.

Fisher (1908) discussed the problems concerning the nomenclature of this genus. He pointed
out that Astropecten of Linck, 1733, is pre-Linnaean, that Astropecten of Schultz, 1760, is non-binomial,

(61) The specific name aranciaca Linnaeus was emended to aurantiaca by Tiedemann, 1816. See H. L. Clark, Carnegie Inst.
Washington, Publ. 566, p. 72, 1946.

100 San Dreco Society oF Natura History [Memorrs
and hence that neither is available. He did not mention the usage of the genus name by Blainville‘®’,
who accepted Linck’s genus. For the present we accept Gray’s usage of the genus name and leave any
further nomenclatural questions concerning it to specialists in the Asteroidea.

Durham and Roberts‘*’’ summarized the known occurrences of fossil asteroids in North America.
They described Astropecten matilijaensis from beds of late Cretaceous age in Ventura County, Cali-
fornia; but this species appears to belong in Archastropecten, where it was placed by Hess (1955, p. 44).
Therefore, Astropecten armatus, from Pliocene beds in San Diego, is the only known fossil Astropecten
in western North America.

Hess‘** reviewing the species of fossil Astropectinidae, transferred most of the previously described
Mesozoic fossils from Astropecten to Archastropecten Hess. The type of this genus is Astropecten
huxleyi Wright, 1862, from strata of late Jurassic age in England. According to Hess, the most
important distinction between the two genera is the character of the flattened surfaces of the joints of
the marginal plates. In Archastropecten these surfaces are large and simple and differ proximally and
distally; consequently, they fit together very closely. In Astropecten these surfaces are smaller, more
deeply excavated, and more differentiated.

Asterias rémondii Gabb‘®’’ was described long ago from beds now referred to the San Pablo
formation of late Miocene age in the San Francisco Bay district in California.

Astropecten armatus Gray
Plate 23, Figures 8, 9

Astropecten armatus Gray, Ann. and Mag. Nat. Hist., Vol. 6, No. 36, p. 181, November, 1840.—Fisher, U. S. Nat. Mus., Bull.
76, Pt. 1, p. 56, pl. 5, figs. 1-2; pl. 7, figs. 3,6; pl. 50, fig. 4; pl. 51, fig. 3, June 30, 1911. San Pedro, California, to Punta
Santa Elena, Ecuador, Recent.—Ziesenhenne, Zoologica, New York Zool. Soc., Vol. 22, Pt. 3, p. 211, October 7, 1937. San
Pedro, California, to Punta Santa Elena, Ecuador; Clarion Island; Recent.

Type SPECIMEN: No. 1938.5.12.27., British Museum (Natural History).

Type Locatity: “Inhab. Puerto Portrero, South America, on sandy bottoms, 9 fathoms. H.
Cuming, Esq. Var. 2.” [Costa Rica. }

Rance: Middle Pliocene to Recent. Recent from San Pedro, California, to Punta Santa Elena,
Ecuador; Clarion Island, Revillagigedo Islands, Mexico. Shore to 146 meters (80 fathoms), on muddy,
sandy, and rocky bottoms. (Ziesenhenne.)

OccuRRENCE IN THE SAN D1EGO FORMATION: UNIVERSITY OF CALIFORNIA AT Los ANGELES: Corner of Market Street
and Euclid Avenue, San Diego.

ORIGINAL DESCRIPTION: Rays elongate, regularly tapering; upper marginal tubercles narrow,
with a continued series of erect, elongated, subulate spines. Var. 2. Pulcher, the under series of marginal
tubercles not produced, and the spines more slender. (Gray).

Diagnostic features of this species given by Fisher (1911, p. 60) follow:

“Armatus may be distinguished from the other two Californian astropectens by the presence of at least a
few superomarginal spines or tubercles, by the broader and more tumid superomarginal plates, by the enlarged
central granules of the paxillae, by the heavier and more bristling inferomarginal armature, and especially by the
chisel-shaped enlarged adambulacral spine, which is broader at tip than at base, and usually more or less
hollowed at the end, on the upper (or outer) side, like a gouge. Even young specimens of armatus have a few
superomarginal tubercles, although these are usually inconspicuous. In lieu of the superomarginal spines the
enlarged central granules of paxillae and the specialized adambulacral spine may be used to determine doubtful
specimens.” (Fisher, 1911.)

(62) Blainville (Dict. Sci. Nat., Vol. 60, p. 220, 1830) cited “(G. Astropecten, Link; Crenaster, Luid.)”, with 30 species,
of which A. aranciaca is the first one.

(63) Durham, J. W., and Roberts, W. A., “Cretaceous Asteroids from California,’ Jour. Paleo., Vol. 22, No. 4, pp. 432-
439, pls. 65, 66, July, 1948. Two new species were described by Durham and Roberts. These are Astropecten matilijaensis (p. 435,
pl. 65, figs. 1-5; pl. 66, figs. 2, 4, 5) and Henricia(?) venturana (p. 437, pl. 66, figs. 1, 3), from “6.3 miles northeast along
the road from Wheeler Springs, on the highway from Ojai to the Cuyama Valley. Referring to the 1942 reprint of the 1903
edition of the Mr. Pinos, Calif. Quadrangle . . . the locality appears to be in the SEl%4 of the SEl4 of Sec. 2, TSN, R23W,
Ventura County, California.”

(64) Hess, H., “Die Fossilen Astropectiniden (Asteroidea). Neue Beobachtungen und Ubersicht iiber die bekannten Arten,”
Schweiz. Palaeo. Abhandl., Bd. 71, No. 3, pp. 1-113, figs. 1-62, pls. 1-4, 1955.

(65) Asterias remondii Gabb, Geol. Surv. Calif., Palaeo., Vol. 2, p. 37, pl. 13, fig. 69, February, 1866. “Found abundantly
at ‘Star Fish Point,’ on the Pinole Ranch, south of the Straits of Carquinez, about five miles from Martifiez; Miocene.”

VotumE II] Marine PLIOCENE OF SAN DieGO, CALIFORNIA 101

Remarks: A portion of a single ray, 13.8 mm. in length and 12 mm. in maximum width, with
8 plates in one series and 6 in the other, is in the collection of the University of California at Los
Angeles. It was collected by B. H. Brattstrom at the corner of Market Street and Euclid Avenue,
San Diego. This fragment is similar in observable characters to the corresponding portion of Astro-
pecten armatus Gray, which at the present time occurs in the waters off San Diego. This conclusion
was afhirmed by Mr. Fred C. Ziesenhenne, who compared the fossil with a series of Recent specimens
of A. armatus in the Allan Hancock Foundation. The fossil is therefore referred to the Recent species.

Class ECHINOIDEA Leske

A paper by the present authors published in 1938°°) contains many references to and discussions
of west American Cenozoic Echinoidea. Since the submission of our monograph on west American
Cenozoic Echinoidea, several important papers have appeared, including those of Ziesenhenne‘®”’, A. H.
Clark“), H. L. Clark’, Caso, and Durham'”!’, as well as the later portions of the great mono-
graph by Mortensen'””?.

Mayr’”®) published an interesting paper dealing with speciation in tropical American echinoids.
C. W. Cooke‘ is the author of two very useful papers dealing with the Cenozoic echinoids of the
eastern United States. A recent paper by Durham and Melville'”’’ deals with the classification of

echinoids.

(66) Grant, U. S., IV, and Hertlein, L. G., “The West American Cenozoic Echinoidea,”’ Publ. Univ. Calif. Los Angeles
Math. Phys. Sci., Vol. 2, pp. i-vi, 1-225, figs. 1-17, pls. 1-30, April 19, 1938.

(67) Ziesenhenne, F. C., “The Templeton Crocker Expedition. X. Echinoderms from the West Coast of Lower California,
the Gulf of California and Clarion Island,” Zoologica, New York Zool. Soc., Vol. 22, Pt. 3, pp. 209-239, figs. 1, 2, October
Fa 937,

(68) Clark, A. H., “Echinoderms from the Pearl Islands, Bay of Panama, with a Revision of the Pacific Species of the
Genus Encope,” Smithson. Miscell. Coll., Vol. 106, No. 5, (Publ. 3849), pp. 1-11, pls. 1-4, July 18, 1946.

(69) Clark, H. L., “A Report on the Echini of the Warmer Eastern Pacific, Based on the Collections of the Velero III,”
Allan Hancock Pac. Exped., Vol. 8, No. 5, pp. 225-352, figs. 1-3, pls. 35-71, December 29, 1948. (“Hubert Lyman Clark:
Teacher and Friend”, by F. A. Chase, Jr., pp. ii-iv and portrait; “Bibliography of Dr. H. L. Clark’s Echinoderm Papers,” by
Marjorie Pattee, pp. v-ix; “Preface”, by Th. Mortensen, pp. xi-xii).

(70) Caso, M. E., “Contribucion al Conocimiento de los Equinoideos de Mexico,” An. Inst. Biol. Mexico, Vol. 17, Nos. 1 &
2, pp. 247-259, figs. 1-10, 1946; also Vol. 19, No. 1, pp. 183-231, figs. 1-24, 1948; Vol. 20, Nos. 1 & 2, pp. 342-355, figs. 1-6,
1949. See also: “Los Equinoides Fésiles del Cenozoico de Mexico,” Bol. Assoc. Mex. Geol. Petrol., Vol. 3, Nos. 1-2, pp. 37-96,
1951; “El Genero Clypeaster Lamarck 1801, en el Terciario de Mexico,” An. Inst. Biol. Univ. Mexico, Tom. 27, No. 2, pp. 487-
528, figs. 1-23, 1 table, 1957.

(71) Durham, J. W., “Classification of Clypeasteroid Echinoids,” Univ. Calif. Publ. Geol. Sci., Vol. 31, No. 4, pp. i-v,
73-198, figs. 1-38, frontispiece and pls. 3-4, November 21, 1955.

(72) Mortensen, Th., “A Monograph of the Echinoidea.”

I. Cidaroidea, text (pp. 1-551, 173 figs.), atlas (pp. 1-24, pls. 1-88), December 7, 1928.

II. Bothriocidaroida, Melonechinoida, Lepidocentroida, and Stirodonta, text (pp. 1-647, 377 figs.), atlas (pp. 1-16,

pls. 1-89), February 22, 1935.

III.1. Aulodonta, text (pp. 1-370, 197 figs.), atlas (pp. 1-22, pls. 1-77), April 25, 1940.
III.2. Camarodonta. I, text (pp. 1-553, 321 figs.), atlas (pp. 1-23, pls. 1-56), February 22, 1943.
III.3. Camarodonta. II, text (pp. 1-446, 215 figs.), atlas (pp. 1-23, pls. 1-66), October 1, 1943.
IV.1. Holectypoida and Cassiduloida, pp. 1-371, pls. 1-14, 326 figs. in text, February 7, 1948.
IV.2. Clypeastroida, text (pp. 1-471, 258 figs.), atlas (pp. 1-20, pls. 1-72), December 30, 1948.
V.1. Spatangoida. I, pp. 1-432, pls. 1-25, 315 figs. in text, December 21, 1950.
V.2. Spatangoida. II, text (pp. 1-593, 286 figs.), atlas (pp. 1-30, pls. 1-64), December 20, 1951.
Index to Vols. I-V, pp. 1-62. Additional note, p. 63, December 20, 1951.

(73) Mayr, E., “Geographic Speciation in Tropical Echinoids,” Evolution, Vol. 8, No. 1, pp. 1-18, figs. 1-7 (maps), March
31, 1954.

(74) Cooke, C. W., “Cenozoic Regular Echinoids of Eastern United States,” Jour. Paleo., Vol. 15, No. 1, pp. 1-20, pls.
1-4, January, 1941; “Cenozoic Irregular Echinoids of Eastern United States,” Jour. Paleo., Vol. 16, No. 1, pp. 1-62, pls. 1-8,
January, 1942.

While the present paper was in press, there appeared another publication of C. W. Cooke: “Cenozoic Echinoids of Eastern
United States”, U. S. Geol. Surv., Prof. Paper 321, pp. i-iii, 1-106, pls. 1-43, 1959.

(75) Durham, J. W., and Melville, R. V., “A Classification of Echinoids,” Jour. Paleo., Vol. 31, No. 1, pp. 242-272, figs.
1-9, January, 1957.

102 San Dieco Soctety oF NaturaL History [ Memorrs

Order CIDAROIDA Claus
Family CIDARIDAE Gray

Test stout, with relatively few plates in each interambulacral column; each plate with one primary
spine or none. Primary spines very large. Primary tubercles perforate. (H. L. Clark, 1925.) Jurassic
to Recent.

KEY (76) TO THE GENERA OF CIDARIDAE

A. Primary spines coarse, ending in a small crown with a central prominence (more rarely tapering

to a fine point) ; pores on peristome partly in double series (not in E. metularia) —..-----....---00------- Eucidaris
B. Primary spines slender, sometimes widened and flattened towards the end; pores on peristome
UR SSIO les Series cece teense acest caste es tecnica state ecu saseeccasts Hesperocidaris

Genus EUCIDARIS Pomel

Eucidaris Pomel, Meéth. et. Gén. Echin. Viv. Foss. [Paléo. Descript. Anim. Foss. de L’Algérie, Zooph. (Alger), Fasc. 2}, p. 109,
1883.—Mortensen, Monogr. Echin. I. Cidaroidea, p. 384, 1928. “Genotype: Cidarites metularia Lamarck.”—Grant and
Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 7, 1938. “Type of the genus (designated by H. L.
Clark, . . . . 1909): Cidaris metularia Lamarck.”

Type species (designated by H. L. Clark, Ann. and Mag. Nat. Hist., Ser. 8, Vol. 3, p. 88,
January, 1909) : Cidaris metularia Lamarck [— Cidarites metularia Lamarck, Anim. s. Vert., Vol. 3,
p. 56, 1816. “Hlabitate l’océan des Grandes-Indes, les Cétes de I’Ile-de-France, celles de Saint-
Domingue.” Illustrated by A. Agassiz, Illustr. Cat. Mus. Comp. Zool., No. 7 (Mem. Mus. Comp.
Zool., Vol. 3), pt. 1, p. 98, 1872; Pt. 3, p. 385, pl. Ic, figs. 23, 23a, 23b, 24, 24a, 24b; pl. 1g, fig. 1;
pl. 35, fig. 3, 1873 (as Cidaris metularia). “Red Sea; Mauritius; East India Islands; Sandwich Islands;
Feejee Islands.” — Mortensen, Monogr. Echin. I. Cidaroidea, p. 386, pl. 41, figs. 1-8; pl. 73, fig. 6;
pl. 86, figs. 11-14, text figs. 113a, 113b, 114, 115 (1), 116, 1928. All over Indo Pacific. }

Rance: Miocene to Recent in West Indies, Panama, and North America. Also Recent on the

west coast of Africa and in the Indopacific region. Bathymetric range, from littoral zone to 570 meters
(311 fathoms).

ORIGINAL DESCRIPTION: Eucidaris. Tubercles a col lisse; trois espéces vivantes; presque toutes
les espéces tertiaries; toutes les espéces crétacées moins une (20); quelques jurassiques seulement
(C. Moieri Honorinae, propinqua, marginata, monilifera, multipunctata) ; la plupart des triasiques (7).
(Pomel. )

SUPPLEMENTARY DESCRIPTION: Pores not conjugate, wall rising into a rounded prominence;
pores on peristome in larger specimens more or less distinctly biseriate (not in metularia). Madreporite
slightly enlarged. Primary spines typically cylindric, terminating in a small crown with a central
prominence; the shaft with low, rounded warts arranged in rather distinct longitudinal series. General
surface of shaft usually covered with a thick, spongy coat of anastomosing hairs. Sometimes the primaries
may be fusiform, tapering to a simple point, sometimes they are very thick, clubshaped. Secondary
spines rather appressed. Large globiferous pedicellariae without an end tooth, with or without a limb
on the stalk. Small globiferous pedicellariae with a small, but distinct end tooth. Tridentate pedicellariae
may occur in two distinct forms, both with long, slender valves. (Mortensen, 1928.)

REMARKS: Pomel mentioned “trois espéces vivantes” in his original description of this genus.
Déderlein, 1887, used the genus Eucidaris in a modern sense and mentioned E. metularia as the first
species. This species was considered to be the type of the genus by H. L. Clark, 1909, by Mortensen,
and by others. Bather (Ann. and Mag. Nat. Hist., Ser. 8, Vol. 3, p. 88, 1909) stated, “We may
well suppose that the ‘trois espéces vivantes’ of Pomel’s list were Cidaris metularia, C. tribuloides, and
C. thouarsi.”

This procedure is not in strict conformity with the International Rules of Zoological Nomenclature.
However, in view of the fact that nearly all workers on Echinoidea accept Cidarites metularia Lamarck
as the type of the genus Eucidaris, we continue this practice.

(76) Adapted from Mortensen, 1928, p. 321.

VotumE II] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 103

Five living species and subspecies of Eucidaris were recognized by Mortensen. Two of these
occur in the warmer waters of western North America.

Eucidaris cf. E. thouarsii Valenciennes
Plate 24, Figures 19-22

The following are references to typical E. thouarsii.

Cidaris thouarsii Valenciennes in L. Agassiz and Desor, Ann. Sci. Nat. (Zool), Ser. 3, Vol. 6, p. 326 [typ. err. 324], 1846.

Eucidaris thouarsti Valenciennes, Mortensen, Monogr. Echin. I. Cidaroidea, p. 393, pl. 42, figs. 5-12; pl. 57, figs. 1 and 2; pl. 73,
figs. 3-5; pl. 86, figs. 1-7; text figs. 115 (2), 117, 118 (1, 3), 1928. Lower California to Panama and the Galapagos Islands,
shore to 45 meters.—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 7, pl. 2, figs. 1, 2,
1938. Earlier records cited. ?Miocene, Pliocene to Recent.—H. L. Clark, Allan Hancock Pac. Exped., Vol. 8, No. 5, p.
229, pl. 35, fig. 1, 1948. Gulf of California to La Plata Island, Ecuador. Also the islands off the coast.

TYPE SPECIMEN: Muséum National d’Histoire Naturelle de Paris‘””?.

Type Locaity: “Californie. (Neboux.) Gallopagos.”

Rance: ?Middle Miocene in California and Lower California, and ?late Miocene, (Tuxpan
formation, Vera Cruz), eastern Mexico. Pliocene to Recent. Recent, common in the western Americas
from San Felipe Bay near the north end of the Gulf of California to La Plata Island, Ecuador; also
Guadalupe Island‘) (C. Limbaugh, coll.), Alijos Rocks and Revillagigedo Islands, Mexico, Cocos
Island and Galapagos Islands, from shore to 139 meters (76 fathoms).

OccurRRENCE IN THE SAN DigGO FORMATION: CALIFORNIA ACADEMY OF SCIENCES: Loc. 12163, Pacific Beach, (spines).
Los ANGELES County Museum: Loc. 122, 20 to 30 feet below end of Loring Street, Pacific Beach, (spines); Loc. 305, 2400
feet east and 1350 feet south of the northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian (see U.S. Geol.
Surv. topographic map, San Ysidro quadrangle, ed. 1943), (spines); Loc. 308, 0.2 mile north of intersection of Harbor Boule-
vard and Tourmaline Street, Pacific Beach, (spines).

ORIGINAL DESCRIPTION: Aires ambulacraires étroites, composées de quatre rangées de granules,
dont les deux internes sont a peine développées. Base des tubercles large. Espace granuleux inter-
médiaire entre les rangées, étroit. Granules assez apparents, peu serrés. Piquants subcylindriques,
enflés, tres granuleux, rappelant ceux du C. Blumenbachii. (Valenciennes. )

Remarks: The fossils recorded here from the San Diego formation are spines. Many were
collected by G. P. Kanakoff at Loc. 305 (LAM), near the Mexican boundary. One of the largest
spines measures 5 mm. in diameter. Similar spines were collected by Kanakoff at Loc. 308 (LAM),
0.2 mile north of the intersection of Harbor Boulevard and Tourmaline Street, and at Loc. 122
(LAM), Pacific Beach. Spines collected by Henry Hemphill from Pliocene strata at Pacific Beach
are in the collections of the California Academy of Sciences.

These spines have been compared with those of a series of Recent specimens of Eucidaris thouarsii
in the collections of the California Academy of Sciences. Mr. Fred C. Ziesenhenne likewise compared
these specimens with Recent ones in the collections of the Allan Hancock Foundation, and he could
detect no essential differences other than those due to weathering. Only spines of the fossil form
are known from the Pliocene beds at San Diego; therefore, we adopt the conservative course and record
only a provisional identification of the species.

The collections of the Los Angeles Museum include a single incomplete but moderately well
preserved plate of a cidarid from Loc. 305 (LAM). Comparing this with plates of Recent species of
Cidaridae, Mr. Ziesenhenne concluded that it resembles plates of Cidaris, Histocidaris, and even
Stereocidaris, more closely than it resembles Eucidaris.

Specimens apparently referable to E. thouarsii occur in beds of Pliocene age in the Galapagos
Islands and in Imperial County, California, and in beds of late Pliocene and Pleistocene age in the

Gulf of California.

(77) Dr. André Franc, Muséum National d’Histoire Naturelle de Paris, informed us (written communication) that Mr. G.
Cherbonnier in that institution made a search for the type specimen of Cidaris thouarsti Valenciennes. Mr. Cherbonnier’s opinion
is that the type may be one of two specimens in the museum which were collected by M. Neboux, but he cannot determine with
certainty whether either of these unnumbered and poorly preserved specimens is the type.

(78) Recent discovery of the occurrence of this species at Guadalupe Island and at Alijos Rocks by members of an expedition
of the Scripps Institution of Oceanography was called to our attention by Edwin C. Allison.

104 San Drieco Society oF NaTurat History [Memoirs

Many years ago a spine from the Monterey formation of late Miocene age in San Mateo County,
California, was submitted by Ralph Arnold to H. L. Clark for identification. The latter stated'”’’,
“I do not think it shows a single feature by which it can be distinguished from thouarsii. If it is not
thouarsii, it is certainly from the ancestor of that species.” Eucidaris thouarsii was cited by Jackson‘*”
as occurring in the Miocene Tuxpan formation, Vera Cruz, Mexico. Toula‘*”’ mentioned that a species
occurring in the Gatun formation of middle or late Miocene age in Panama shows a relationship with
Eucidaris tribuloides Lamarck and with E. thouarsit.

Loel and Corey'*”? cited “Cidaris thouarsii(?) Valenciennes (Kew) ” from beds of middle Miocene
age in the Santa Ana and Santa Monica mountains. We have not studied specimens from those areas.

Eucidaris thouarsii galapagensis Déderlein from the Galapagos Islands has thick club-shaped
spines with the collar of the primaries somewhat longer than that of typical thouarsii. H. L. Clark did
not consider this form worthy of recognition, but Mortensen (1928, p. 399, pl. 42, fig. 13; pl. 86, figs.
8-10) believed it to be at least a valid variety and perhaps a distinct species. Both E. thouarsii and the
form galapagensis occur at the Galapagos Islands.

Genus HESPEROCIDARIS Mortensen

Hesperocidaris Mortensen, Vid. Medd. Dansk. Nat. For. Kgbenhavn, Bd. 85, p. 73, 1928. “Genotype: Dorocidaris panamensis
A. Agassiz.’—Mortensen, Monogr. Echin. I. Cidaroidea, p. 415, 1928. “Genotype: “Dorocidaris’ panamensis A. Agassiz.”
—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 9, 1938. “Type (by original designa-
tion): Dorocidaris panamensis A. Agassiz.”

Type species (by original designation) : Dorocidaris panamensis A. Agassiz”) [Bull. Mus.
Comp. Zool., Vol. 32, No. 5, p. 73, pl. 1; pl. 2, fig. 1, 1898. Off Cocos Island, in 66 and in 100
fathoms. Off Galera Point, in 85 and in 112 fathoms. Also illustrated by A. Agassiz, Mem. Mus.
Comp. Zool., Vol. 31, pp. 20-23, pls. 1-4; text figs. 3, 12, 22-24, 26-29, 43-45, 1904. Original locality
cited. Bathymetric range, 66-112 fathoms. —Mortensen, 1928, pp. 416-419, pl. 18, fig. 8; pl. 73, fig. 8;
pl. 82, figs. 23-29; text figs. 124-127, 1928. —H. L. Clark, Allan Hancock Pac. Exped., Vol. 8, No. 5,
p. 230, pl. 35, fig. 2, 1948. ] ;

RANGE: Paleocene to Recent, western America. Recent from the Gulf of California to Galera
Point, Ecuador; also Clarion Island, Cocos Island, and Galapagos Islands; in from 55 to 274 meters
(30 to 150 fathoms).

DescriPTION: Pores not conjugate, wall nearly flat; pores on peristome in single series. Madre-
porite not enlarged. Primary spines slender, with low granules arranged in longitudinal series; cylindrical,
not tapering, but sometimes conspicuously widened and flattened towards the end, the surface covered
with a thick, spongy coat of anastomosing hairs. Secondary spines not strongly appressed. Large
globiferous pedicellariae without an end tooth and without a limb on the stalk. Small globiferous
with a small end tooth. Tridentate pedicellariae of one form only, with slender valves. (Mortensen,
1928, p. 415.)

Remarks: Hesperocidaris resembles Stylocidaris (see Mortensen, 1928, p. 334; type, Cidaris
affinis Philippi) in general characters. The two genera differ, however, in the character of the primary
spines. Those of Stylocidaris usually taper to a fine point, the hairs on the surface of the shaft are
usually simple, sometimes lacking, and the large globiferous pedicellariae possess a well developed
limb on the stalk. Stylocidaris is essentially an Indo-Pacific genus represented in those waters by about
16 species. Two species occur in the Caribbean and one of them also in the mid-Atlantic and
Mediterranean.

So far as known, fossil and Recent species of Hesperocidaris occur only in the western Americas.

(79) Clark, H. L., in Arnold, R., Proc. U. S. Nat. Mus., Vol. 34, No. 1617, p. 359, August 8, 1908.
(80) Jackson, R. T., Proc. U. S. Nat. Mus., Vol. 84, No. 3015, p. 229, 1937.
(81) Cidaris sp., Toula, Jahrb. Kais.-Kgl. Geol. Reichsanst., Bd. 58, Heft 4, p. 735, 1909.

(82) Loel, W., and Corey, W. H., “The Vaqueros Formation, Lower Miocene of California. I. Paleontology,” Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 22, No. 3, p. 167, December 31, 1932. Also p. 141.

(83) Fred C. Ziesenhenne (verbal communication) pointed out to us that Stylocidaris houstonia A. H. Clark (Smithson.
Miscell. Coll., Vol. 98, No. 11 (Publ. 3536), p. 12, pl. 4, figs. 10, 11; pl. 5, figs. 12-14, June 2, 1939, “Galapagos Islands:
Tagus Cove, Albemarle Island; from the anchor chain in 50 fathoms (91 m.) of water.”) is identical with Hesperocidaris
panamensis A. Agassiz.

Votume II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 105

Hesperocidaris perplexa H. L. Clark
Plate 24, Figures 6, 7,9, 10, 12, 14
Tretocidaris perplexa H. L. Clark, Bull. Mus. Comp. Zool., Vol. 51, No. 7, p. 205, pl. 6, figs. 1, 2; pl. 7, figs. 1-4, December,

1907.

Hesperocidaris perplexa H. L. Clark, Mortensen, Monogr. Echin. I. Cidaroidea, p. 421, pl. 42, fig. 14; pl. 73, fig. 7; pl. 82,
figs. 30-31, 1928. Gulf of California in 65-70 meters. Clarion Island (locality perhaps not reliable) —H. L. Clark, Allan
Hancock Pac. Exped., Vol. 8, No. 5, p. 231, pl. 36, fig. 3, December 29, 1948. South of San Benito Islands and the Gulf
of California. Bahia Honda, Panama, north of Gorgona Island, Colombia, and La Plata Island, Ecuador, Recent.

Cidaris sp., Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 7, April 19, 1938. “Pacific Beach,”
Pliocene.

Type SPECIMEN: No. 188, Museum of Comparative Zoology, Harvard University.

Tyr Locatity: “Two of the five known specimens of this species were collected by the ‘Alba-
tross’ in the Gulf of California on a bottom of coarse sand, in 36-39 fathoms. The other three are
said to have been picked up on the shore of Clarion Island, the westernmost of the Revilla Gigedo
Islands.” According to H. L. Clark (1948) the type locality is “Gulf of California.”

Rance: Middle Pliocene to Recent. Recent from south of the San Benito Islands to Lat. 29°39'N.
in the Gulf of California, and from Bahia Honda, Panama, to La Plata Island, Ecuador, in 13 to 110
meters (7 to 60 fathoms).

OccurRENCE IN THE SAN Dreco FORMATION: CALIFORNIA ACADEMY OF Sciences: Loc. 1183, Eagle Street, just north
of Quince Street, just east of Reynard Way, (spines); Loc. 1401, south slope of Soledad Mountain, first canyon west of Rose
Canyon, (spines); Loc. 28892, near Mexican boundary, (spine); Loc. 28893, corner of India and Upas streets, San Diego,
(spines). Los ANGELES County Museum: Loc. 122, 20 to 30 feet below end of Loring Street, Pacific Beach, (fragment and
spines); Loc. 180, 2220 block on east side of La Jolla Boulevard at intersection with Trias Street, back of excavation, (spine) .
San Dreco Society or Naturat History: Pacific Beach, (plate); Loc. 80, south slope of Soledad Mountain, first canyon
west of Rose Canyon, (spines); Loc. 150, Pacific Beach, (spines). UNrversrty OF CALIFORNIA: Loc. A-8333, 2400 feet east and
1350 feet south of the northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian (see U. S. Geol. Surv.
topographic map, San Ysidro quadrangle, ed. 1943), (spines).

ORIGINAL DESCRIPTION: Test somewhat flattened; vertical diameter, about .55 h. d.; coronal
plates 7 or 8; areolae small, only .60-.65 of horizontal length of plate, distinct and not very deeply
sunken; median interambulacral area very fully covered with tubercles, smallest next to vertical suture,
which is quite distinct; ambulacra about one-third of interambulacra in width; poriferous zones, broad
and little sunken; median ambulacral area with a double series of tubercles on each margin, inner much
smaller, and between these, 3-6 irregular series of small tubercles which sometimes, but not always,
conceal vertical suture; pores nearly horizontal, large, their horizontal diameter much exceeding vertical.
Abactinal system about .40 h. d., nearly circular and clearly defined, flat and quite thickly covered
with small secondary spines; genital plates rather large, nearly square or somewhat pentagonal, with
pores near outer edge; ocular plates more or less triangular, with apex truncated, when in contact with
anal system, either wholly excluded, or some, or all except right anterior one, in contact with a large
anal plate; anal system about one-half of abactinal, with an external series of 10-12 large plates and
12-15 smaller ones at centre; except along margins all plates of abactinal system covered with rather
coarse tubercles of nearly uniform size; each genital plate has 50-80+ such tubercles and each ocular
20-35-£. Actinostome small, only about .35 h.d., not at all sunken, closely covered with stout plates,
4 in each interambulacrum and about 10 pairs in each ambulacrum. Primary spines short, about equal
to h. d., nearly cylindrical, seldom tapering, but often flattened and widened at tip, covered with 14-24
longitudinal series of coarse, sharp granules; actinal primaries much as in Cidaris and nearly smooth;
secondaries, long and narrow, but rather thick and often with a deep longitudinal furrow on outer
surface at tip, which is thus crescent-shaped in cross-section. Pedicellariae not peculiar; no large
globiferous ones were found, but small globiferous and tridentate, like those of dubia, are frequent.
General color of test decidedly greenish, especially abactinally; miliary spines greenish; secondary spines
greenish with a broad longitudinal stripe of deep reddish-purple; primary spines dull grayish with a
bright olive-green base and collar. Largest specimen, 50 mm. h. d.; vertical diameter, 27 mm.; abactinal
system, 20 mm.; actinostome, 18 mm.; longest spine, 40 mm., 3 mm. thick at base, 5 mm. wide at tip.

(H. L. Clark.)

106 San Dieco Society oF Naturat History [Memorrs

Remarks: This species, cited as Cidaris sp. by the present authors in 1938, is represented by a
fairly well-preserved plate from Pacific Beach in the collections of the San Diego Society of Natural
History and by numerous spines in this and other collections available to us. Mr. Fred C. Ziesenhenne
carefully compared these with a series of specimens in the Allan Hancock Foundation. According to
him, if we allow for changes due to weathering and fossilization, these agree in all particulars with
specimens of the Recent Hesperocidaris perplexa H. L. Clark. Comparison with specimens of the Recent
species leads the authors to the same conclusion. A number of spines similar to those mentioned above
are present in the collections of the California Academy of Sciences from various localities in San Diego
and also in the collection of the Los Angeles County Museum.

H. L. Clark (1948) mentioned that the tests of large adult specimens attain a diameter of about
43 mm. and a height of 25 mm., with primary spines 35 to 43 mm. in length. He pointed out that the
spines of this species do not show the characteristic flattening and widening at the distal end until they
attain a length of about 30 mm. Some of the fossil spines in the present collections are similarly
flattened.

This species differs from the related Recent west American species H. dubia H. L. Clark and
H. panamensis A. Agassiz‘**) in the smaller peristome and apical system, in the close tuberculation of
the interporiferous zone, and in the distally widened and flattened primary spines. H. L. Clark pointed
out (1948) that “the striking and very constant feature of the coloration in perplexa is the conspicuous
broad, brown longitudinal stripe which occurs on all the spinelets.” Mortensen considered “the character
of the large globiferous pedicellariae lacking the limb on the stalk” to be important in the classification
of this species.

Among the spines of Eucidaris cf. E. thouarsii collected by H. Hemphill from Pliocene beds at
Pacific Beach, there are several which in general characters resemble those of Hesperocidaris panamensis
A. Agassiz. The largest of these (incomplete) measures 34 mm. in length and 3.6 mm. in diameter.
These spines were compared by Mr. Fred C. Ziesenhenne with those of Recent specimens of H.
panamensis in the collections of the Allan Hancock Foundation. He stated that the fossil spines differ
only in size from those of the Recent form. The difference in size, and the fact that no test referable
to H. panamensis has been found, have led us merely to mention their occurrence here rather than to
discuss them under a separate caption.

Hesperocidaris merriami Arnold”) is represented by spines in the Martinez formation, Paleocene,
in San Mateo County, California. These are quite similar to the spines of H. perplexa, but they bear
only 13 or 14 longitudinal rows of spinules. H. L. Clark considered this Paleocene species to be the
precursor of H. perplexa.

Hesperocidaris lorenzanus Kew‘*®), described from beds referred by Arnold to the San Lorenzo
formation, Oligocene, was based upon spines. The spines are smaller than those of H. merriami,
smooth toward the base, and ornamented above with fewer (about 10) but much more prominently
nodose longitudinal ribs. According to H. L. Clark (quoted by Arnold), this species probably is
referable to the same genus as H. perplexa.

A characteristic feature of Hesperocidaris asteriscus H. L. Clark (1948), from Panama, is said
to be the star-like figure formed by the genital plates.

A portion of a spine from Loc. 1400 (CAS), Pacific Beach, differs from spines of H. perplexa

in possessing more rows of closely compacted spinules. Mr. Ziesenhenne suggested that this might
represent a rapidly developing juvenile spine but that it could hardly be referred to H. perplexa.

(84) For reference to this species see p. 104.

(85) Cidaris merriami Arnold, Proc. U. S. Nat. Mus., Vol. 34, No. 1617, p. 359, pl. 32, fig. 8, August 8, 1908. “Santa
Cruz quadrangle, San Mateo County, locality No. 25, ridge between headwaters of San Lorenzo River and Pescadero Creek.”
“Martinez formation, lower Eocene.”

(86) Cidaris branneri Arnold, Proc. U. S. Nat. Mus., Vol. 34, No. 1617, p. 363, pl. 33, fig. 5, August 8, 1908. “Santa
Cruz quadrangle, Santa Cruz County, locality No. 109, on Bear Creek, 4 miles above its confluence with the San Lorenzo River.”
“San Lorenzo formation, Oligocene, upper portion transitional toward Vaqueros formation, lower Miocene.” (Not Cidaris bran-
neri White, 1888. Brazil, Cretaceous.) Renamed Cidaris lorenzanus Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12, No.
2, p. 52, pl. 3, fig. 4, 1920.

Votume IJ] Marine PLIOCENE OF SAN D1EGo, CALIFORNIA 107

Order ARBACIOIDA Gregory
Family ARBACIIDAE Gray

Teeth keeled; ambulacral plates compound, with 3-5 elements in each plate; primordial inter-
ambulacral plates present; periproct with (normally) 4 or 5 equal plates; primary tubercles imperforate.

(H. L. Clark, 1925.) Late Jurassic to Recent.

Genus ARBACIA Gray

Arbacia Gray, Proc. Zool. Soc. London for 1835, p. 58, June 1, 1835. Original list includes “Arbacia pustulosa (Echinus pustu-
losus, Lam.), Arb. punctulata (Ech. punctulatus, Lam.), &c.’”—Lambert and Thiéry, Essai Nomencl. Raison. Echinoid.,
Fasc. 4, p. 270, March, 1914. “Type: A. pustulosa Klein (Cidaris).”—H. L. Clark, Cat. Rec. Sea-Urchins Brit. Mus.,
p. 69, 1925. “Type, Cidaris pustulosa Leske, 1778 = Echinus lixula Linné, 1758. Syst. Nat., ed. 10, p. 664.”—Mortensen,
Monogr. Echin. II. Bothriocidaroida, Melonechinoida, Lepidocentroida, and Stirodonta, p. 562, 1935. “Genotype: Cidaris
pustulosa Leske = Echinus lixula Linnaeus.”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol.
2, P. 18, April 19, 1938. Earlier records cited. “Type of the genus (according to H. L. Clark, 1908): Cidaris pustulosa

eske.”

Synonyms of this genus cited by Mortensen are: Echinocidaris Desmoulins, 1835; Agarites L.
Agassiz, 1841; Anapesus Holmes, 1860; Pygomma Troschel, 1872.

Type spectes (designated by H. L. Clark, Mem. Mus. Comp. Zool., Vol. 34, No. 2, p. 67, 1908) :
“Type-species, Cidaris pustulosa Leske, 1778.” [Cidaris pustulosa Leske, Add. ad Klein, p. 150, pl. 11,
figs. A-D, 1778. Also illustrated by A. Agassiz, Illustr. Cat. Mus. Comp. Zool., No. 7, (Mem. Mus.
Comp. Zool., Vol. 3), Pt. 1, p. 92; Pt. 2, p. 263, pl. 2, fig. 4; pl. 5, figs. 1-18, 1872. Atlantic
Ocean. “Littoral—125 fathoms.” Pt. 3, p. 402, pl. 1g, fig. 5; pl. 2a, figs. 15-33; pl. 5, figs. 19-21; pl. 28,
fig. 6; pl. 38, figs. 10a-c, 1873. “Mediterranean; Liberia; Brazil.” —Mortensen, Monogr. Echin. II,
p. 566, pl. 70, fig. 13; pl. 87, figs. 11, 12, 1935 (placed under Arbacia lixula Linnaeus). |

Rance: Late Miocene'*”) to Recent. Pliocene to Recent in the western Americas. Recent on
the west and east coasts of the Americas, Angola, Africa, to the Mediterranean, and Tristan da Cunha
Island in the south Atlantic. Bathymetric range, intertidal zone to 315 meters (172 fathoms) (according
to Mortensen). Most species occur in less than 182 meters (100 fathoms).

DescriPTION: Test solid, of medium size, up to c. 70 mm. diameter, low hemispherical or sub-
conical, flattened on the oral side. Ambulacra with compound, 3-geminate plates; pore-zone straight,
narrow above the ambitus, conspicuously widened on the oral side. Primary ambulacral tubercles in
a regular series throughout. Interambulacra with numerous primary tubercles, arranged in horizontal
and vertical series; on the upper side there is mostly a conspicuous naked, but not sunken inter-
ambulacral space, only the outer series of tubercles reaching to the apical system, the other series
generally disappearing at the ambitus or at some distance from the apical system. No secondary
tubercles. Generally the epistroma is conspicuously developed and may be of a characteristic design.
Apical system dicyclic or with one to three of the oculars insert. Ocular pores double. Peristome very
large, the ambulacra protruding so as to form “ambulacral lips.” Gill-slits rather deep and wide.
Peristomial membrane naked, with numerous small plates imbedded. Primary spines moderately long,
scarcely exceeding diameter of test, straight, cylindrical, stout, often flattened at the end, but not
pointed; on the oral spines the cortex-layer is present as a small terminal “shoe” or “cap”; the ambital
and upper spines without any cortex-layer. Pedicellariae tridentate, triphyllous and ophicephalous.
Sphaeridia single, only one in each ambulacrum, placed in a small pit in the median line, close to
the peristomial edge. Spicules usually smooth rods, widened and with some holes in the middle.
Colour mostly dark, the denuded test as a rule beautifully coloured, reddish, purplish or greenish.
(Mortensen, 1935.)

Remarks: Six species and one subspecies of this genus were cited by Mortensen as occurring in
the seas at the present time. Three species occur in west American waters between Newport Bay,
California, and Cape Horn. One of these is well known in the Magellanic region; the other two occur
in warm temperate and tropical waters, rarely below 91 meters (50 fathoms).

(87) Cooke (Jour. Paleo., Vol. 15, No. 1, p. 11, 1941) cited Arbacia aldrichi Clark from beds of late Oligocene age, but
later he placed this species in the genus Arbia Cooke (see Cooke, C. W., U. S. Geol. Surv., Prof. Paper 321, p. 21, 1959).

108 San Drieco Society oF Natura History [Memoirs

Arbacia incisa A. Agassiz
Plate 26, Figures 6, 8, 10

Echinocidaris incisa A. Agassiz, Bull. Mus. Comp. Zool., Vol. 1, No. 2, p. 20, August 15, 1863. Guaymas and Panama.

Arbacia incisa A. Agassiz, H. L. Clark, Bull. Amer. Mus. Nat. Hist., Vol. 32, p. 220, 1913. “San Josef” [San Jose] Island, San
Esteban Island, and Agua Verde Bay, Gulf of California—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math.
Phys. Sci., Vol. 2, p. 19, pl. 4, fig. 1; pl. 30, fig. 13, April 19, 1938. Pliocene to Recent.—H. L. Clark, Allan Hancock
Pac. Exped., Vol. 8, No. 5, p. 244, pl. 40, fig. 11, December 29, 1948. Numerous records from Newport Harbor, California,
to the Middle Chincha Island, Peru, Recent.

Arbacia stellata (Blainville; ?Gmelin), Mortensen, Monogr. Echin. II, Bothriocidaroida, Melonechinoida, Lepidocentroida, and
Stirodonta, p. 575, pl. 68, figs. 8-10; pl. 70, figs. 6-9; pl. 71, fig. 7; pl. 87, figs. 13, 14, February 22, 1935. Lower California
to Peru and the Galapagos Islands, Recent.

TyPE SPECIMEN: “Cotype” (according to H. L. Clark), No. 467, Museum of Comparative
Zoology, Harvard University.

Type tocauity: “Guayamas, Panama.” According to H. L. Clark (1948, p. 246) the type
locality is “Guaymas,” Sonora, Mexico.

RANGE: Pliocene to Recent. Recent from Newport, California, (Ziesenhenne“**)), to the Middle
Chincha Island, Peru, Lat. 13°39'15’'S., from the littoral zone to 91 meters (50 fathoms).

OccurRRENCE IN THE SAN DrEGO FORMATION: CALIFORNIA ACADEMY OF SCIENCES: Pacific Beach.

ORIGINAL DESCRIPTION: Abactinal system very prominent, sutures between the plates well marked;
tubercles large, spines short, stout, color yellowish-brown. (A. Agassiz.)

Remarks: A single small test of an echinoid, 7.6 mm. in diameter and 3.8 mm. high, was collected
at Pacific Beach by Professor E. Dean Milow, San Diego State College, who generously presented it
to us. Mr. Fred C. Ziesenhenne compared this with young specimens of Arbacia incisa in the Allan
Hancock Foundation. He stated that the ocular plates, pore pairs, tubercles, and other visible characters

of the test, were similar to corresponding structures of the specimens of A. incisa. We therefore refer
the test to that species.

This species is also known to occur as a fossil in Pliocene beds in Ecuador and probably in the
Pliocene strata on Cedros Island, Mexico, and in Pleistocene beds at Magdalena Bay, Lower California,
Mexico, and in Ecuador.

Mortensen (1935) presented arguments for placing Arbacia incisa in the synonymy of Echinus
stellatus Blainville ‘°°’ and perhaps in the earlier Echinus stellatus Gmelin®®. H. L. Clark (1948)
stated, “Nobody knows to what sea-urchin the name stellatus was first given.” In an earlier paper,
however, H. L. Clark‘) also used the name Arbacia stellata for the present species. In view of the
doubtful application of the name Echinus stellatus as used by Agassiz and by Blainville, we use the
name Arbacia incisa, which is well known to west American authors.

The largest recorded size for this species, cited by H. L. Clark, is a diameter of 60 mm. It is the
only species of Arbacia in west American waters north of Ecuador. The tests of Recent specimens are
readily identified by the reddish patches on the bare interambulacral areas on the aboral surface.

The test of Recent Arbacia dufresnii Blainville is greenish on the interambulacral areas. The ocular
plates are wide and concave distally, and there are but few spines and tubercles on the aboral inter-
ambulacral areas. This species occurs from La Plata, Ecuador, to Puerto Mont on the coast of Chile
and at the antarctic island of Booth Wandel and at the Falkland Islands.

The test of Arbacia spatuligera Valenciennes lacks red or green coloration, and it has club-shaped
spines on the aboral surface. It ranges from Guayaquil, Ecuador, to southern Chile.

(88) Ziesenhenne, F. C., Bull. South. Calif. Acad. Sci., Vol. 40, Pt. 3, pp. 118-120, September-December, 1941, issued
January 31, 1942.

(89) Echinus stellatus Blainville, Dict. Sci. Nat., Vol. 37, p. 76, 1825. “J'ai établi cette espece d’aprés un individu de la
collection du Muséum, confondu & tort avec 10. piquete de M. de Lamarck.”

(90) Echinus stellatus Gmelin, Syst. Nat., ed. 13, Tom. 1, Pars VI, p. 3174, 1788. “Habitat in mari americano.” Ref. to
“Seb. mus. 3.t.13, £.7.”

(91) See Bull. Mus. Comp. Zool., Vol. 52, No. 17, p. 345, October, 1910.

Votume II] Marine PLIOCENE OF SAN D1IEGO, CALIFORNIA 109

Order ECHINOIDA Claus

Suborder CAMARODONTA Jackson
Family ECHINIDAE Gray

Ambulacral plates compound, typically of 3 elements; ambitus circular; test without sculpturing
or pits (H. L. Clark, 1925.) Late Paleogene to Recent. (Durham and Melville.)

Genus LYTECHINUS A. Agassiz

Lytechinus A. Agassiz, Bull. Mus. Comp. Zool., Vol. 1, p. 24, August 15, 1863. Three species cited under the genus. “Lytechinus
carolinus Ag.” “South Carolina, Georgia, and Florida”; “Lytechinus variegatus A. Ag.” “Cienfuegos, Hayti”; “Lytechinus
atlanticus A. Ag.” “Bermudas.”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 23,
1938, “Type of genus (designated by Verrill, 1867): Echinus variegatus Leske.”—Mortensen, Monogr. Echin. II.2. Cama-
rodonta. I., p. 434, February 22, 1943. “Genotype: Lytechinus variegatus (Lamarck).”

Type species (designated by Verrill, Trans. Connecticut Acad. Arts and Sci., Vol. 1, Pt. 2,
p. 302, 1867): “The Echinus variegatus may be regarded as the type.” [Leske, Add. ad Klein, pp. xviii,
149, pl. 10, figs. B, C, 1778. Illustrated by Mortensen, 1943, p. 437, pl. 24, figs. 3-5; pl. 25, figs. 1-12;
pl. 53, figs. 1, 6, 7, 11-13 (as Lytechinus variegatus). Common over all the West Indian region; north
to North Carolina and Bermuda and south to Santos, Brazil. }

RANGE: Early Miocene to Recent. Recent, eastern Pacific, West Indies, west Atlantic, and Cape
Verde Islands, in warm temperate and tropical waters, from the intertidal zone to 540 meters (295
fathoms).

DescriPTIon: Buccal membrane usually heavily plated; a primary tubercle on each ambulacral
plate; gill cuts deep; ocular I, and sometimes V, insert, as a rule. (H. L. Clark, 1925.)

Remarks: Lytechinus was included in the family Echinidae by H. L. Clark, who discussed the
problems of its classification (1925, pp. 104-105); but Mortensen (1943) placed it in the family
Toxopneustidae Troschel. Tests range from small to quite large. The tests usually are low and
rounded, and the ambulacra contain trigeminate plates, each with a primary tubercle. There is usually
a bare median space in the aboral portion of each interambulacral area.

A specimen from early Miocene strata on Santa Rosa Island, California, was identified by H. L.
Clark as very near to Lytechinus pictus Verrill, differing only slightly in details of tuberculation. Lack
of details on fossil specimens led Mortensen to question whether some should be referred to Lytechinus.
He mentioned, however, (1943, p. 435) that L. coreyi Grant and Hertlein, described from early
Miocene beds in California, is probably the forerunner of the Recent west American species.

Mortensen cited ten species and subspecies in his key to the Recent species of Lytechinus. These are
restricted to warm temperate and tropical waters. The four eastern Pacific species range from Santa
Barbara, California, to Ecuador and the Galapagos Islands. The Atlantic species range from North
Carolina and Bermuda Island to Santos, Brazil, and one species reaches the Cape Verde Islands.

Lytechinus species

OccuRRENCE IN THE SAN D1gGO FORMATION: Los ANGELES County Museum: Loc. 122, 20 to 30 feet below end of
Loring Street, Pacific Beach.

Remarks: A fragment of an echinoid test, 40 mm. in diameter, and a piece of a spine, were
collected by J. F. Arndt at Loc. 122 (LAM), Pacific Beach. Both bear a general resemblance to
Lytechinus pictus Verrill®”. These were examined by Mr. Fred C. Ziesenhenne, who stated that the
observable plates, bearing three pore pairs in each arc, and the spine, resemble comparable portions
of L. pictus. He added, however, that the fossil is larger than any Recent specimen of that species in the
collections of the Allan Hancock Foundation.

The fossil specimen is so incomplete and so imperfectly preserved that no illustration is given. It
seems desirable, however, to record the presence of the genus Lytechinus in the San Diego formation.

(92) Psammechinus pictus Verrill, Trans. Connecticut Acad. Arts and Sci., Vol. 1, Pt. 2, p. 301, June, 1867. “Cape St.
Lucas, Cal.—J. Xantus, (Smithsonian Institution) .”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol.
2, p. 25, pl. 5, figs. 4-6; pl. 15, figs. 6, 7, 1938. Miocene to Recent.—Mortensen, Monogr. Echin. III. 2. Camaradonta.I., p. 450,
pl. 53, figs. 2, 8, 1943—H. L. Clark, Allan Hancock Pac. Exped., Vol. 8, No. 5, p. 249, pl. 41, fig. 15, 1948. Newport, Cali-
fornia, to the Gulf of California and perhaps south to Gorgona Island, Colombia, and La Plata, Ecuador, (although the records
of occurrences at the two latter localities may represent L. panamensis Mortensen) in 0 to 95 fathoms.

110 San Dieco Socrery or Natrurat History | Memotrs

Lytechinus pictus has been recorded as occurring in Pliocene strata on Cedros Island, Lower
California, Mexico.

Family STRONGYLOCENTROTIDAE Gregory

Ambitus circular; no pits or sculpturing on the coronal plates; ambulacral plates compound, usually
with 4 or more elements (rarely 3). (H. L. Clark, 1925). Miocene to Recent.

Genus STRONGYLOCENTROTUS Brandt

Strongylocentrotus Brandt, Rec. Actes Séance Publ. Acad. Impér. Sci. St. Petersbourg for 1834, p. 263 (in separate p. 63), issued
1835. Species in original list: Echinus chlorocentrotus Brandt (p. 264) and ?Echinus tuberculatus Blain. (p. 264).—H. L.
Clark, Mem. Mus. Comp. Zool., Vol. 34, p. 352, 1912. “Type-species, Strongylocentrotus chlorocentrotus Brandt, l.c., p.
264 (or 64) = Echinus drobachiensis O. F. Miller, 1776.”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math.
Phys. Sci., Vol. 2, p. 31, 1938. Type (by virtual monotypy): Strongylocentrotus chlorocentrotus Brandt (= Echinus dré-
bachiensis O. F. Miller) —Mortensen, Monogr. Echin. III. 3. Camarodonta. II., p. 193, October 1, 1943. “Genotype: Stron-
gylocentrotus chlorocentrotus Brandt = drgbachiensis (O. Fr. Miiller).”

Euryechinus Verrill, Proc. Boston Soc. Nat. Hist., Vol. 10, pp. 340, 341, 1866. “A new name must be adopted for the present
group, having E. drobachiensis as its type.”

Type species [by virtual monotypy, Strongylocentrotus chlorocentrotus Brandt, 1835, p. 264
(= Echinus drébachiensis O. F. Miiller, Prod. Zool. Dan., p. 235, 1776) } (designated by the Inter-
national Commission on Zoological Nomenclature in Opinion 208, March 8, 1954): Echinus
drobachiensis O. F. Miller. {Illustrated by A. Agassiz, Illustr. Cat. Mus. Comp. Zool., No. 7
(Mem. Mus. Comp. Zool., Vol. 3), Pt. 1, p. 162; Pt. 2, p. 277, 1872; Pt. 3, p. 441, pl. 4a, figs. 2, 3, 6,
1873 . North Europe; North Pacific; northeast America. (Contains extensive synonymy.) —NMorten-
sen, Danish Ingolf-Exped., Vol. 4, Pt. 1, Echin. (1), pp. 162, 165, pl. 1, figs. 5, 6; pl. 2, figs. 3-5;
pl. 16, figs. 4, 9, 11, 13, 17, 21, 23; pl. 20, figs. 3-6, 12, 13, 16, 18, 20, 25, 26, 29, 1903. Wide distribu-
tion in the North Atlantic and North Pacific Oceans. —Grant and Hertlein, Publ. Univ. Calif. Los
Angeles Math. Phys. Sci., Vol. 2, p. 33, pl. 4, fig. 6; pl. 6, fig. 1, 1938. North Europe; North Pacific;
northeast coast of North America. —Mortensen, Monogr. Echin. III.3. Camarodonta. II., p. 198,
figs. 92a, b, 93a, 95; pl. 23, figs. 1-11; pl. 69, figs. 1-3, 10, October 1, 1943. (With synonymy.) Cir-
cumpolar; to Puget Sound in western North America and to northern Scotland in the Atlantic. }

Rance: Miocene of Oregon (Arnold). Pliocene to Recent in California and Lower California.
Recent, North Pacific, and one species circumboreal and ranging to northern Scotland and to Chesapeake
Bay, from the littoral zone to 1600 meters (875 fathoms) ; off California, littoral zone to 125 meters
(68 fathoms).

ORIGINAL DESCRIPTION: Aculei teretes, subulati, conformes et magnitudine tantum inaequales.

(Brandt. )

SUPPLEMENTARY DESCRIPTION: Pore pairs 4 to 10, but usually not more than 7; valve of
globiferous pedicellariae with a powerful end tooth but no lateral teeth. (H. L. Clark, 1925.)

REMARKS: Strongylocentrotus is widespread in the northern seas at the present time. This genus
is characteristic of cold and temperate waters, but in west American waters ranging south to San
Bartolomé Bay (Turtle Bay), Lower California. Mortensen included ten living species in the genus,
only one, the type of the genus, ranging through the Arctic seas and into the North Atlantic as far
as Scotland. This distribution, states Mortensen, strongly points toward a North Pacific origin of
Strongylocentrotus.

Species attributed to Strongylocentrotus have been cited from Miocene strata in France, but
according to Mortensen these probably are referable to Paracentrotus Mortensen. Cooke (1941, p. 19)
indicated that the record (Clark and Twitchell, 1915) of the occurrence of Strongylocentrotus dro-
bachiensis in the Caloosahatchie beds of Pliocene age in Florida needs confirmation.

Two species of Strongylocentrotus occur off California in shallow depths, generally among rocks
up to the intertidal zone but sometimes to depths of 161 meters (88 fathoms). Swan’? recently dis-
cussed the species of this genus occurring in the waters of the northeast Pacific.

(93) Swan, E. F., “The Strongylocentrotidae (Echinoidea) of the Northeast Pacific,’ Evolution, Vol. 7, No. 3, pp. 269-
273, September 30, 1953. See also “Regeneration of Spines by Sea Urchins of the Genus Strongylocentrotus,” Growth, Vol. 16,
pp. 27-35, 1952.

Votume II] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 111

The species from southern California described as Strongylocentrotus fragilis Jackson’*’ has been
referred by some later workers to Allocentrotus Mortensen; this occurs in deeper water, often 73 to
110 meters (40 to 60 fathoms) but sometimes as deep as 1170 meters (640 fathoms) (H. L. Clark,
1948.)

The diagnostic characters of this genus cited in Mortensen’s key to the family Strongylocentrotidae
are as follows: ambulacra gradually constricted on the oral side, at the peristomial edge distinctly nar-
rower than the interambulacra; spicules of the globiferous pedicellariae simply bihamate; test very fragile.

KEY TO THE SPECIES OF STRONGYLOCENTROTUS

A. Primary spines very long (50-60 mm.) ; test usually exceeding 75 mm. in diameter; 2 rows of

primary tubercles in each interambulacrum decidedly larger than adjacent ones; arcs of

Ohl Olpore’ pats steep yas oping sete rats tre ee eves et: Seen meen fe ee ee franciscanus
B. Primary spines short. usually not exceeding 15-20 mm.; test usually not exceeding 75 mm. in

diameter; 2 rows of primary tubercles in each interambulacrum not exceptionally larger

than adjacent ones; arcs of usually 8 pore pairs, approaching horizontal arrangement................ purpuratus

Strongylocentrotus franciscanus A. Agassiz
Plate 19, Figure 28

Toxocidaris franciscanus A. Agassiz, Bull. Mus. Comp. Zool., Vol. 1, p. 22, August 15, 1863. San Francisco, California. Recent.

Strongylocentrotus franciscanus A. Agassiz, A. Agassiz, Illustr. Cat. Mus. Comp. Zool., No. 7 (Mem. Mus. Comp. Zool., Vol. 3),
Pr. 1, p. 163 (in part), 1872; Pt. 3, p. 442 (in part); pl. 5b, figs. 1, 2; pl. 7, figs. 10, 10a, 1873. Localities cited from
Puget Sound to San Diego, California, Recent.—Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12, No. 2, table opp. p.
52, 1920. “San Diego,” “Pliocene.” (Not pl. 4, figs. la-c = ?Echinometra van-brunti A, Agassiz)—Grant and Hertlein,
Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 34, fig. 14; pl. 2, fig. 6; pl. 6, fig. 3, 1938. “San Diego
(Kew)”.—Mortensen, Monogr. Echin. III.3. Camarodonta.II., p. 242, figs. 106-110; pl. 28, figs. 1-7; pl. 29, figs. 1-4;
pl. 30, figs. 2-3; pl. 31, figs. 1-2; pl. 32, figs. 1-3; pl. 61, figs. 10, 15-19, 23, October 1, 1943. Kodiak Island, Alaska, to
Cedros Island, Lower California, and northern Japan, Recent.

TYPE SPECIMEN: “Cotype” (according to H. L. Clark, 1948) No. 1686, Museum of Com-
parative Zoology, Harvard University.

Type Locatity: “San Francisco,” California. Recent.

Rance: Middle Pliocene to Recent. Recent from Kodiak Island, Alaska, to Cedros Island and
Thurloe Point, Lower California, Mexico. (?) Hakodate, Japan (see Mortensen, 1943, p. 246). From

the littoral zone to 125 meters (68 fathoms) (Mortensen).

OccuRRENCE IN THE SAN DiEGO FORMATION: San Diego (Kew; Grant and Hertlein). CarirorNiA ACADEMY OF ScI-
ENCES: Loc. 12163, Pacific Beach. Los ANGELES County Museum: Loc. 305, 2400 feet east and 1350 feet south of the north-
west corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian (see U. S. Geol. Surv. topographic map, San Ysidro
quadrangle, ed. 1943). UNiversiry oF CALIFORNIA: Loc. A-8333, locality same as Loc. 305 (LAM). University oF CALI-
FORNIA AT Los ANGELES: corner of Market Street and Euclid Avenue, San Diego (fragment) (B. Brattstrom coll.).

ORIGINAL DESCRIPTION: This species grows to a very large size. High coronal plates, large open-
ings for suckers. Pores arranged in arcs of nine pairs. Two very prominent rows of large tubercles
in interambulacral space. The large tubercles of ambulacra of same size as secondary of interambulacra.
Spines long, tapering gradually, equalling in length two thirds the diameter of test. (A. Agassiz.)

Remarks: Portions of two small tests, the larger about 21.5 mm. in diameter, were collected by
Henry Hemphill at Loc. 12163 (CAS), Pacific Beach. A comparison of these with specimens of
Strongylocentrotus franciscanus of similar size reveals no appreciable differences.

A fragment of a test, (UCLA coll.), 25.5 mm. in altitude and 15 mm. in diameter, from Market
Street and Euclid Avenue in San Diego, appears to represent a portion of a basal ambulacrum of the
present species. In the size and arrangement of the pore pairs and in the slope of the arcs, this fragment
is very similar to corresponding parts of Recent specimens of Strongylocentrotus franciscanus.

A fragment of a spine 14.8 mm. in length from Loc. A-8333 (UC), from southwestern San Diego
County, appears to be referable to this species. It occurs with a fragment of a spine of Hesperocidaris.

(94) Strongylocentrotus fragilis Jackson, Mem. Boston Soc. Nat. Hist., Vol. 7, p. 128, January, 1912. “. . . at Catalina
Island, off the southern California coast. . .” Also “dredged off the coast of southern California and Oregon in depths of 124 to
339 fathoms.”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 34, pl. 29, fig. 1, 1938. Van-
couver Island, British Columbia, to Point Santa Eugenia, west coast of Lower California in deep water.—Mortensen, Monogr.
Echin. III.3, Camarodonta. II., p. 255, pl. 30, figs. 10-17; pl. 61, figs. 4, 5, 7, 11, 12, 14, text figs. 117-119, October 1, 1943
(as Allocentrotus fragilis). Ca. 50-1150 meters.

112 San Dieco Society oF Naturat History [Memoirs

Spines of S. franciscanus also are present in collections of the Los Angeles County Museum from this
locality, Loc. 305 (LAM).

The tests of large specimens of Strongylocentrotus franciscanus attain a diameter of 160 mm., and
some have been recorded which, with the spines, measured a foot in diameter. The spines of this
species are light reddish, brownish, or occasionally purple; on young specimens the tips are white but
not banded.

Strongylocentrotus franciscanus differs from S. purpuratus, with which it sometimes occurs at the
present time, in that the test is much larger, the primary spines are much longer (50 to 60 mm.), and
the arcs of pore pairs are more nearly vertical and consist of 9 or 10 rather than about 8 pore pairs.
Furthermore, in the midzone of each interambulacrum are two rows of very large tubercles, each row
flanked on each side by a row of smaller tubercles: thus each coronal plate has three prominent tubercles,
the middle one largest. The corresponding tubercles on S. purpuratus are much more nearly uniform
in size. Also, S. franciscanus has fewer coronal plates: at a diameter of 60 mm. it has 16 or 17, whereas
S. purpuratus of the same size has about 28 to 30. Mortensen considered S. franciscanus to be closely
related to S. nudus A. Agassiz, of Japan.

Mortensen (1943, p. 242-247) gave a full discussion of the morphology and distribution of this
species. He pointed out that individuals living in surf have spines shorter and thicker than are those of
individuals living in calm water.

Swan”) mentioned that this species, in the Puget Sound region, often occurs abundantly a few
feet below tide level on vertical faces of rock. He stated that it occurs on intertidal rocky areas on
San Juan Island and Lopez Island, Washington, often with S. purpuratus and S. drobachiensis as well
as with what are probably hybrids of these species. S. franciscanus occurs abundantly in rocky places
along the coast of northern and central California, generally in deeper tide pools than does S. purpuratus.

It is said to have been used for food at times by the Indians and Greeks along the coast of British
Columbia.

Strongylocentrotus purpuratus Stimpson
Plate 19, Figure 29

Echinus purpuratus Stimpson, Boston Jour. Nat. Hist., Vol. 6, p. 526, April, 1857. “Near San Francisco.”

Strongylocentrotus purpuratus Stimpson, Arnold, U. S. Geol. Sury., Prof. Paper 47, p. 28, 1906. “Pacific Beach,” “San Diego
formation,” Pliocene—W. B. Clark and Twitchell, U. S. Geol. Surv., Monogr. 54, p. 223, 1915. “San Diego formation
(upper part), Pliocene.”—Kew, Univ. Calif., Publ. Bull. Dept. Geol., Vol. 12, No. 2, opp. p. 52, p. 58, 1920. “Pacific Beach,
San Diego County,” Pliocene—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 37, pl. 4,
figs. 4 and 5; pl. 6, fig. 2; text figs. 13 and 15, 1938. “Pliocene-—San Diego, California.” Also earlier records cited.—
Mortensen, Monogr. Echin. III.3. Camarodonta.II., p. 236, figs. 102b, 103b, 105; pl. 26, figs. 1-8; pl. 27, figs. 5, 7-9; pl.
32, fig. 4; pl. 61, figs. 6, 20-22, 24, October 1, 1943. Vancouver Island, and perhaps Sitka, Alaska, to Cedros Island, Lower
California, from littoral zone to about 20 meters.

TYPE SPECIMEN: No. 2495, United States National Muesum.
Type Locatity: “Found at low-water mark on rocky ocean shores near San Francisco.” California.

RANGE: Questionably in the middle Miocene of Oregon (“cf.” Arnold, 1906) ; Pliocene to Recent
in California. Recent from Sitka, Alaska (Rathbun; see Mortensen, 1943, p. 241), and Puget Sound,
Washington, to Cedros Island, Lower California, Mexico, from the littoral zone to about 20 meters
(11 fathoms).

OccuRRENCE IN THE SAN D1EGO FORMATION: San Diego formation (Arnold; Clark and Twitchell); Pacific Beach (Kew);
San Diego, earlier records (Grant and Hertlein). Los ANGELES County Museum: Loc. 153, cliff 50 feet above sea level, south
of the end of Loring Street, Pacific Beach; Loc. 305, 2400 feet east and 1350 feet south of the northwest corner of Sec. 8,
Tei R.2W., San Bernardino Base and Meridian, (spines) (see U. S. Geol. Surv. topographic map, San Ysidro quadrangle,
ed. 1943).

ORIGINAL DESCRIPTION: Form depressed. Outline somewhat pentangular. Ambulacral areas of
the same width as the interambulacrals; (sometimes even wider;) with eight pairs of pores in each of
the very oblique rows, which are separated from each other by rows of small tubercles. Interambulacral
area with six rows of larger tubercles, between which smaller ones are interspersed; the tubercles of
the two rows next within the exterior ones are largest. Auricles slender. Spines of moderate length,
rather stout and blunt. Color, deep purple. Diameter, 21/ inches; height, 1 1/3 inch. (Stimpson.)

(95) Swan, E. F., Evolution, Vol. 7, pp. 270, 271, 1953.

Votume II] Marine PLIOCENE OF SAN DrgEGO, CALIFORNIA 113

Remarks: A portion of a single somewhat crushed test, 79.5 mm. in diameter and approximately
38 mm. in altitude, in the collections of the Los Angeles County Museum, is referable to this species.
The character of the tubercles as well as the nearly horizontal arrangement of the pore pairs agrees with
the corresponding portions of tests of Recent specimens of Strongylocentrotus purpuratus.

This specimen came from Loc. 153 (LAM), in a cliff 50 feet above sea level at Pacific Beach.
According to the information concerning the locality, there was an element of doubt in the mind
of the collector, W. C. Woynar, as to whether the specimen came from beds of Pliocene or of Pleisto-
cene age. However, the brown indurated matrix in which the specimen was embedded is exactly similar
to that of the Pliocene strata in that area, and accordingly we consider the specimen to be of Pliocene age.

Spines referable to Strongylocentrotus purpuratus also are in a collection of the Los Angeles
County Museum from Loc. 305 (LAM), near the Mexican boundary.

This is a common purple sea urchin along the west coast of the United States. Occasionally adult,
and especially young, specimens may be green, or the spines may be banded reddish and white. The
test is often about 50 to 60 mm. in diameter but occasionally is larger. Swan mentioned specimens
from San Juan Island, Washington, which measured from 89 to 99 mm. in diameter. The spines are
much shorter than those of S. franciscanus, usually not exceeding about 20 mm. in length. The test is
smaller than that of S. franciscanus, and there are usually about 8 pore pairs in each arc rather than 9
to 10, and these arcs are more nearly horizontal. Furthermore, the primary tubercles on the inter-
ambulacral areas of S. purpuratus are more nearly the same size as the adjacent ones than are those of
S. franciscanus, and there are also more numerous coronal plates.

Swan® discussed the occurrence of this species in the Puget Sound region and mentioned that
specimens occur there which appear to be hybrids between S. purpuratus and S. drébachiensis and
between S. purpuratus and S. franciscanus. The same author'’”’ pointed out that the regenerated
spines of S. purpuratus are purple instead of the green color which juvenile specimens may have. Also,
this species has a great preference for areas of rough water, and the test is tougher and heavier than
those of S. drébachiensis and S. franciscanus; consequently, it is best fitted for survival if torn loose
and washed over rocks in the surf. According to Swan the spines regenerated by Strongylocentrotus do
not have the same number of wedges or cycles as do the original spines.

Mortensen (i1943, p. 236-242) gave a comprehensive discussion of the morphology and charac-
teristics of this species. He stated that he had never seen hybrids between S. purpuratus and S.
drobachiensis and that he considered S. purpuratus to be quite a distinct species.

Mortensen (1943, p. 240) doubted the statement that S. purpuratus has the ability to bore cavities
in rocks. Irwin'°*) has shown that this species as well as S. franciscanus does form such cavities. She
reported that on a pier near Santa Barbara, California, these urchins occupied circular depressions in
steel piling and that the surface of the steel was rust-free and shiny beneath them and thus constantly
exposed to the corrosive action of the sea water. Branner'°®) long ago pointed out that even the hardest
rocks are bored by sea urchins in Brazil.

The food of this species consists of algae and other organic material which it finds on the rocks.
Some early accounts mention that this species was at one time sold in the markets of San Francisco,
where it was purchased for food by Italian residents.

Family ECHINOMETRIDAE Gray

Ambitus more or less elliptical; no pits or sculpturing of coronal plates; ambulacral plates com-
ound, with 3-19 elements, but usually more than 4; oculars exsert or becoming insert in sequence
P > y g

V, I, IV (not I, V, IV as usual). (H. L. Clark, 1925.) Middle Eocene to Recent.

(96) Swan, E. F., Evolution, Vol. 7, p. 270, 1953.

(97) Swan, E. F., Growth, Vol. 16, pp. 32-34, 1952.

(98) Irwin, M., “Steel-Boring Sea Urchins,” Pac. Discovery (Publ. Calif. Acad. Sci.), Vol. 6, No. 2, pp. 26, 27, 3 illustr.,
March-April, 1953.

(99) Branner, J. C., “Syllabus of a Course of Lectures on Elementary Geology,” (Stanford University, California) ed. 4,
p. 246, fig. 57, also pl. 18, 1912.

114 San Dieco Society oF Natrurat History [Memorrs

Genus ECHINOMETRA Gray

Echinometra Gray, Ann. Phil., Vol. 26 (n.s. 10), p. 426, 1825 (as of Bryerius [Breynius, 1732]). Species in original list: E.
lucunter Linnaeus, E. atratus Klein, and E. mammillatus Klein—H. L. Clark, Cat. Rec. Sea-Urchins Brit. Mus., p. 142,
1925. “Type, Echinus lucunter Linné.”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p.
39, April 19, 1938. Type as indicated by Lambert and H. L. Clark.—Mortensen. Monogr. Echin. III.3. Camarodontra. II.,
p. 352, 1943. “Genotype: Echinometra lucunter (Linnaeus ).”

Synonyms of this genus cited by Mortensen are: Ellipsechinus Liitken, 1864; Plagiechinus Pomel,
1883; Mortensenia Déderlein, 1906. There is an Echinometra of Meuschen, 1778, but this name has
not been generally used.

Tyee species (designated by Lambert, Mém. Soc. Paléo. Suisse, Vol. 37, p. 48, 1911, and by H. L.
Clark, Mem. Mus. Comp. Zool., Vol. 34, p. 370, 1912): Echinus lucunter Linnaeus. {Syst. Nat.,
ed. 10, p. 665, 1758. “Habitat in O. Indico.” Ref. to Gualtieri, Index Test. Conchyl., pl. 107, fig. C
(as Echinus ovalis, etc.), 1752. Also illustrated by Mortensen, 1943, p. 357, figs. 172-175, 177; pl.
41, figs. 1-5; pl. 42, figs. 12-14; pl. 43, figs. 1-13; pl. 44, fig. 9; pl. 64, figs. 17, 20-24. Florida to Desterra,
Brazil; West Indies; Bermuda; St. Helena; Dakar to Angola, Africa. }

RANGE: Eocene!) (Nummulitique de l’Inde) to Recent. Recent, in very warm temperate and
tropical waters in the Pacific, Atlantic, and Indo-Pacific, from the intertidal zone to about 53 meters
(29 fathoms).

Description: Test usually elongately oval, rather strong, moderately large to large, white or
with tinge of purple or greenish; ambulacral plates of 4 to 8 elements; periproct with numerous plates;
ambulacra with 3 pore pairs to each arc at the peristomial edge, the number increasing to 4 to 10 pore
pairs above; auricles usually large; the primary spines moderately long, pointed, sometimes clavate,
varying from brown to black, purple, or white. (Adapted from Mortensen and H. L. Clark.)

Remarks: Adult members of this genus can usually be separated from those of Strongylocentrotus
by the elongately oval test and by the large auricles, Juvenile forms may be but slightly elongated.

About six species and two or three varieties of this genus occur in the seas at the present time.
Three species, Echinometra insularis H. L. Clark, E. oblonga Blainville, and E, van-brunti A. Agassiz

occur in eastern Pacific waters.

The present authors (1938) pointed out that the genus Echinometra is represented in the Pliocene
of Ventura County, California, by a specimen illustrated by Kew''°”) under the name of Strongylo-
centrotus franciscanus. This specimen appears to be referable to Echinometra van-brunti A. Agassiz.
The latter species also has been recorded as occurring in beds of late Pliocene age at Santa Barbara,
California. The species described under the name of Heliocidaris stenopora H. L. Clark, from Acapulco,
Mexico, is now believed to be identical with Echinometra van-brunti.

Echinometra species

Plate 26, Figures 4, 5

Echinometra sp., Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 41, April 19, 1938. “Lower
beds of the San Diego Pliocene at Pacific Beach.”

OccuRRENCE IN THE SAN Disco FORMATION: CALIFORNIA ACADEMY OF ScrENCcES: Loc. 1413, lower beds of the Plio-
cene section at Pacific Beach.

Remarks: A small, slightly crushed test 19.2 mm. in maximum diameter and 8.3 mm. in height,
is in the collections of the California Academy of Sciences from Loc. 1413 (CAS), from Pliocene
beds in the lower portion of the section exposed at Pacific Beach. The late H. L. Clark stated that
the species was undeterminable but that the test appeared to be referable to the genus Echinometra. This
generic assignment was recently confirmed by Mr. Fred C. Ziesenhenne at the Allan Hancock Founda-
tion in Los Angeles.

(100) See remarks by Mortensen, 1943, p. 355.

(101) Strongylocentrotus franciscanus A, Agassiz, Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12, No. 2, pl. 4, figs.
la-c, 1920,

Votume II] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 115

Order CLYPEASTEROIDA L. Agassiz
Family DENDRASTERIDAE Lambert

Medium-sized to large, flattened, usually well-developed internal supports; petals well formed, a
few isolated pores outside petals; paired petals more or less closed, anterior petal more widely open;
outer member of pore-pair elongated; interambulacrum 5 discontinuous on oral surface; interambulacra
nearly as wide as ambulacra at ambitus; basicoronal interambulacral plates larger than ambulacral
plates; 4 genital pores; periproct inframarginal to supramarginal; ambulacral food grooves bifurcating
or trifurcating just outside basicoronal plates. (Durham, 1955.) Pliocene to Recent, Pacific Coast of
North America and Japan.

KEY TO THE GENERA OF DENDRASTERIDAE
A. Apical system usually decidedly eccentric posteriorly; paired petals usually partially closed;

Pilar pits OLE test so Ore Cel ys RENN eae eseee cee cencer eee ae aecee a ceene danse e arene eset eae cata eeeeseccees ccee Dendraster
B. Apical system only slightly eccentric posteriorly; paired petals usually open; margins of test
Eka cheer ence rectal cl is ese eae ae eer a Se ee eee ene Merriamaster

Genus DENDRASTER L. Agassiz

Dendraster L. Agassiz, in Agassiz and Desor, Ann. Sci. Nat. (Zool.), Ser. 3, Vol. 7, p. 135, 1847. Only species “exeentricus
Agass.—Echinarachnius excentricus Val., Zool. Venus, pl. 10, Californie (Neboux).—Mus. Paris.” —H. L. Clark, Mem. Mus.
Comp. Zool., Vol. 46, p. 69, 1914. “Type, Scutella excentrica Eschscholtz.”—Lambert and Thiéry, Essai Nomencl. Raison.
Echinid., Fasc. 4, p. 319, 1914. “Type: D. excentricus Eschscholtz (Scutella).” See also Fasc. 9, p. 584, 1925.—Grant and
Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 78, 1938. “Type of the genus (by monotypy) :
‘exeentricus Agass.—Echinarachnius excentricus Val., Zool. Venus. pl. 10, Californie’.”,—Durham, Univ. Calif. Publ. Geol.
Sci., Vol. 31, No. 4, pp. 100, 158, 1955. “Type species: Dendraster excentricus L. Agassiz = Scutella excentrica Esch-
scholtz = Echinarachnius excentricus Valenciennes, monotypic.”

Echinarachnius A. Agassiz. (in part), Illustr. Cat. Mus. Comp. Zool., No. 7, (Mem. Mus. Comp. Zool., Vol. 3), Pt. 1, p. 107;
Pr. 2, p. 315, 1872; Pr. 3, p. 524, 1873.

Not Echinarachnius Gray, 1825.

Type SPECIES (by monotypy): “exeentricus Agass. —Echinarachnius excentricus Val., Zool.
Venus. pl. 10, Californie.” [—= Scutella excentrica Eschscholtz, Zool. Atlas, Heft 4, p. 19, pl. 20,
figs. 2a-c, 1831. “An der Kuiste der Insel Unalaschka, am Kamtschatischen Meere.” —Grant and
Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 84, figs. 16, 17, 1938 (with
synonymy). —Mortensen, Monogr. Echin., IV.2. Clypeastroida. II, p. 382, fig. 222, pl. 60, figs.
1-5; pl. 61, figs. 1, 6; pl. 63, fig. 3, December 30, 1948. —Durham, Univ. Calif. Publ. Geol. Sci.,
Vol. 31, No. 4, figs. 1d, 4c, 5b, 11, 20, 21a, 21b, 26), 33, 1955. }

RANGE: Early Pliocene to Recent. Most abundant in late Pliocene: known to occur from central
California to the Gulf of California. Recent from the island of Unalaska, Alaska, to near Cape San
Lucas, Lower California, Mexico. (Latter locality cited by H. L. Clark, 1948.) From the intertidal
zone to about 91 meters (50 fathoms), perhaps occasionally deeper.

Description: Medium-sized to large, flattened; apical system often posteriorly excentric, raised;
margins of test moderately thin; paired petals moderately closed, anterior petal elongated, more open
than paired petals; a few isolated primary pores outside petals; periproct inframarginal, close to margin,
between second and third pair of post-basicoronal plates; peristome central; ambulacral food grooves
complexly developed, usually extending onto aboral surface, usually strongly developed posteriorly;
basicoronal plates relatively small, interambulacral plates about twice as large as ambulacral plates;
interambulacra all discontinuous on oral surface, separated by a pair of ambulacral plates; 3 or 4
post-basicoronal interambulacral plates to column on oral surface; posteriorly 5 or 6 and anteriorly 7 or
8 pairs of post-basicoronal ambulacral plates on oral surface. (Durham, 1955.)

Remarks: The test of this genus is quite distinct from that of any other genus: it is characterized
by the eccentric apical system with elongated anterior petal, by the thin margins, and by the infra-
marginal periproct. It is easily separated from Scutellaster Cragin by the eccentric apical system and
the inframarginal rather than supramarginal periproct. Scutellaster Cragin is an earlier name for
Anorthoscutum Lambert and Thiéry and for Calaster Kew. The synonymy of this genus has been

discussed by Durham””?,

(102) Durham, J. W., “Scutellaster and Anorthoscutum,” Jour. Paleo., Vol. 27, No. 1, pp. 147-149, 1 fig., January, 1953.

116 San Dreco Society oF Naturat History [Memoirs

Eighteen species and subspecies of this genus have been recorded from the Pliocene and Pleisto-
cene of California and Lower California. Fossil forms described since our paper on Echinoidea in 1938
are Dendraster granti Durham, from Pliocene strata on the east coast of Lower California, and D.
elsmerensis Durham, from southern California.

Four species and one subspecies occur in west American waters. In addition to Dendraster
excentricus Valenciennes and its variety elongata H. L. Clark, which were mentioned in our earlier
paper, H. L. Clark (1948) has described three others. These are Dendraster laevis from north of
Santa Barbara Island, California, in 27 to 37 meters (15 to 20 fathoms), D. mexicanus from Rosario
Bay, Lower California, in 27 meters (15 fathoms), and D. rugosus from the Bay of San Sebastian
Vizcaino, Lower California, in 31 meters (17 fathoms). The latter species appears to be identical with
D. vizcainoensis Grant and Hertlein, which originally was described from Quaternary beach deposits
at the same bay.

Durham (1955, p. 159), suggested that in Dendraster the eccentricity of the apical system and
the degree of greater posterior development of the food grooves of a particular species may be correlated
with the position assumed by individuals of the species, whether on edge, slightly tilted, or lying flat.

He suggested that noneccentric species are probably those which lie flat upon the sea bottom.

On the basis of a statistical analysis of variation, especially in degree of eccentricity, Raup''°”

concluded that two ecological races of Dendraster excentricus were recognizable. Individuals occurring
in sheltered bays were less eccentric than those occurring on open coasts. However, he found no syste-
matic geographic variation based upon this character.

There is certainly much variation in many of the species in this genus, but the characters relied
upon for specific differentiation by Kew, by Woodring, and by Stewart, taken together with the strati-
graphic occurrence of the specimens, appear to justify such specific discrimination.

H. L. Clark (1948) reported specimens of Dendraster excentricus from the coast of Oregon that
measured 75 mm. in length, 80 mm. in width, and 12 to 14 mm. in height. A large specimen of
Dendraster venturaensis Kew, collected by Margaret Bennett and C. M. Carson from strata of late
Pliocene age on the ridge west of Coles Canyon, Ventura County, California, measures 100 mm. in
length (anteroposterior), 112 mm. in width.

Individuals of Dendraster often live on fine sandy bottoms over which tidal currents flow, crowded
together, more or less steeply inclined, and with the anterior fourth of the test buried in the sand.
They occur abundantly from intertidal sands to a depth of about 37 meters (20 fathoms) and then
become less abundant to a depth of about 91 meters (50 fathoms) or perhaps occasionally deeper.

Observations on pigments of Dendraster excentricus and D. laevis have been recorded by Goodwin
and Fox‘),

KEY TO THE SPECIES OF DENDRASTER
A. Apical system only slightly eccentric posteriorly; petals slightly raised .................--..-.eessescseeceeeseeseeeseeeeeeeneees casseli
B. Apical system decidedly eccentric posteriorly; petals not raised
a. Margin thin; petals usually narrowly open at end; anterior odd petal very broad; test
usually wider than long
b. Apical system very eccentric; posterior petals diverging and forming nearly a straight line............ ..ashleyi
bb. Apical system less eccentric; posterior petals diverging and forming a decidedly obtuse
EN (d [ae 8 el a ISI ek cA “ine ne ee Oe ROIS RR SRG AORN ates SCT ashleyi ynezensis
aa. Margin moderately thick; posterior petals widely open at end; anterior odd petal not excep-
tionally broader than the others; test often as long as wide or longer and usually not
exceeding 45 mm. in length... Fitsetcc nesta eee eA MEAS SE Pa Reh SS gibbsii humilis

(103) Raup, D. M., “Dendraster: A Problem in Echinoid Taxonomy,” Jour. Paleo., Vol. 30, No. 3, pp. 685-694, figs. 1-
4, May, 1956.

(104) Goodwin, T. W., and Fox, D. L., “Some Observations on Pigments of the Pacific Sand Dollars, Dendraster excen-
tricus and Dentraster [Dendraster} laevis,” Experimentia, Vol. 11, No. 7, pp. 270-276, 1955. See also Univ. Calif. Scripps Inst.
Oceanogr., Contrib. for 1955, New Ser., No. 773, pp. 353-359, figs. 1-4, July, 1957.

VotumeE II] MarINnE PLIOCENE OF SAN DiEGO, CALIFORNIA 117

Dendraster ashleyi Arnold
Plate 21, Figures 1-3, 6; Plate 22, Figures 1, 3; Plate 26, Figure 9

Echinarachnius ashleyi Merriam, Arnold, U. S. Geol. Surv., Bull. 322, p. 58, pl. 24, figs. 6, 7, 1907.

Scutella ashleyi Arnold, J. P. Smith, Calif. State Mining Bureau, Bull. No. 72, p. 38, 1916. “San Diego and lower Fernando
formations of the coastal region of southern California.”

Dendraster ashleyi Arnold, Hertlein, Stanford Univ. Bull., Ser. 5, No. 78, pp. 84, 85, 1929. “San Diego Pliocene.”—Grant and
Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p- 80, pl. 11, fig. 1; pl. 22, fig. 5 (reproduction of
original figure); pl. 30, fig. 4, 1938. “11/4 kilometers west of Cockatoo Grove, and about 7 kilometers east of Chula Vista”;
“north and also west side of Chollas Valley’; “east of Balboa Park, San Diego.”—Hertlein and Grant, Mem. San Diego
Soc. Nat. Hist., Vol. 2, Pt. 1, p. 59, 1944. “Just west of Cockatoo Grove,” Pliocene.—Woodring, U.S. Geol. Surv., Prof.
Paper No. 222, pp. 104, 106, 1950. “San Diego district. Inland localities.” “San Diego formation.”—Hertlein and Grant,
Calif. State Div. Mines, Bull. 170, chapter 2, p. 60, 1954 (1955). “San Diego formation.”

TYPE SPECIMEN: No. 165,259, United States National Museum,

Type Locatity: “Graciosa Ridge, near Orcutt,” California, “Fernando (Pliocene).” [“Graciosa
member of the Careaga on Graciosa Ridge” (Woodring, 1950, p. 68).]

Rance: Middle Pliocene in central and southern California and northern Lower California.

OccurrENCE IN THE SAN Dro FORMATION: San Diego (J. P. Smith; Hertlein and Grant; Woodring); north and
west sides of Las Chollas Valley, San Diego; and east of Balboa Park, San Diego (Grant and Hertlein). CatirorNIA ACADEMY
OF Sciences: Loc. 1175, 11/4, kilometers west of Cockatoo Grove and about 7 kilometers east of Chula Vista; (cf.) Loc. 1405,
street cut 0.2 mile southwest of Alamo Drive and Center Street, east San Diego; Loc. 28883, 0.4 mile north of Broadway exten-
sion (Federal Avenue) on Fairmount (47th Street) (form approaching ynezensis); Loc. 28884, embankment on Windsor Drive
where Tourmaline Street would intersect if projected; Loc. 28890, 0.4 mile north of Broadway on Fairmount Avenue. Los
ANGELES County Museum: Loc. 106, back of house 3030 on west side of Reynard Way, San Diego; Loc. 296, street cut
on northwest side of Fairmount extension, 0.4 mile north of intersection with Broadway, on west side of Las Chollas Valley, San
Diego [approximately same as Loc. 28883 (CAS) }; Loc. 306, on east side of Euclid Avenue, between Federal Boulevard and
intersection of Euclid and Home avenues, San Diego; Loc. 311B, about 15 feet above base of bluff on recent road cut at Loc.
311A, on Windsor Drive; east gate of Navy Hospital, San Diego; above barnacle bed, at southwest corner of intersection of
Home and Fairmount avenues, San Diego; east side of 2400 block on Euclid Avenue, San Diego.

This species was first illustrated and named, without description, by Arnold. The first formal
description of a typical specimen was given by Kew (Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12,
No. 2, pp. 115-116, September 28, 1920) as follows:

DescriPTION: Test of medium size. Measurements of specimen No. 11043 {Univ. Calif. Coll. }:
anteroposterior diameter 62.5 mm., transverse diameter 74 mm., greatest height 6 mm. Markedly thin.
Marginal outline subquadrate, the posterior margin being broadly truncated; transverse diameter the
greater, with its greatest width in the posterior portion of the test. Upper surface rises gently to the
summit, which is posterior to the center of the test and in front of the apical system; greatest elevation
within the radius of the length of the petals. Apical system situated far back near the posterior margin.
Madreporite pentagonal in outline, with four genital pores opposite the four anterior corners. Lateral
petals not symmetrical, the anterior rows of pores in each petal being curved to a greater degree than
those of the posterior rows. Petals of the bivium relatively short, and diverging so as to form with
their axes an angle of nearly 180 degrees. Poriferous areas comparatively wide, each being about
one-half the width of the interporiferous area. Petals of the trivium of the same length; lateral ones
somewhat narrower than the odd anterior one. Poriferous areas of the anterior lateral petals equal
to about one-half to one-third the width of the interporiferous area; poriferous areas of the odd petal
exceedingly narrow, each being about one-eighth the width of the interporiferous area. Inferior surface
very slightly concave to the peristome. The latter is small and round. Dichotomously branching
ambulacral furrows extend in well marked lines from the peristome to the margin, but become less
distinct toward their extremities, especially those of the odd anterior set. Periproct small, subcircular,
inframarginal, and placed about twice its own diameter from the edge of the test. Fine tubercles entirely
cover the test. The test of this species is relatively more elevated in the younger than the older
specimens. (Kew.)

Remarks: Typical specimens of Dendraster ashleyi differ from D. gibbsii and other species of
the genus Dendraster, by their very thin margins, the very broad curvature of the posterior margin,
the very eccentric apical system, and the divergence of the petals of the bivium to form nearly a straight
line. This latter feature is not so pronounced on Arnold’s figure of the type specimen as in most
specimens. The odd anterior petal (III) is usually wider than the others, and all the petals are usually
only narrowly open at the ends.

118 San Dreco Society oF Natura History [Memoirs

This species occurs in the San Diego formation at several localities in the San Diego area. A
specimen from Loc. 1175 (CAS), 114 kilometers west of Cockatoo Grove and about 7 kilometers
east of Chula Vista, is definitely referable to Dendraster ashleyi, as are a number of specimens collected
by G. P. Kanakoff and J. F. Arndt at various localities in the San Diego area. One such specimen
collected by Arndt on Euclid Avenue measures 66 mm. in anteroposterior diameter, 72.8 mm. in
transverse diameter.

Kew suggested that Dendraster ashleyi probably is a descendent of D. gibbsii; but Woodring
(1950, p. 103) stated that, despite the very eccentric apical system, the thin test suggests closer relation-
ship to D. coalingaensis Twitchell”.

Durham (1955, p. 157) pointed out that two separate lineages appear at about the same time
at the base of the Pliocene. These are represented by Dendraster gibbsii, with thick margins and an

inframarginal periproct, and D. elsmerensis Durham“ with thin margins and a marginal periproct.

Some specimens of Dendraster ashleyi bear a general resemblance to D. pentagonalis Israelsky""”?,

which was described from beds of Pliocene age on Cedros Island, Lower California; but they differ
from that species in the thinner margins, the generally more eccentric apical system, the large size of
the odd anterior ambulacral petal, and the usually less decidedly pentagonal outline of the test.

According to Woodring, Dendraster ashleyi is abundant in the Graciosa member of the Careaga
sandstone in the Santa Maria district of southern California. Dibblee°*’ reported finding it more
abundant in the lower Careaga sandstone in Santa Barbara County in the district where he studied

the geology.

In addition to its occurrence in western San Diego County and in Santa Barbara County,
Dendraster ashleyi has been recorded from Pliocene strata in California in the Sargent oil field in
Santa Clara County and also in San Benito County; it also is reported at Turtle Bay and on terraces
east of San Quintin, Lower California, Mexico.

Dendraster ashleyi ynezensis Kew
Plate 21, Figures 4, 5; Plate 22, Figures 2, 4, 6, 8; Plate 26, Figure 7

Dendraster ashleyi var. inezanus Kew (Ms), Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12, No. 1, p. 15, November 20,
1919. From a soft tan and gray sandstone on the north side of the Santa Ynez River, Fernando formation, Pliocene. [No
description or figure. } 3

Dendraster ashleyi ynezensis Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12, No. 2, p. 116, pl. 36, figs. 2a, 2b, September
28, 1920. Santa Ynez River district, Santa Barbara County, California. Upper Fernando formation, upper Pliocene—Grant
and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 81, pl. 9, fig. 7, 1938. Various localities in San
Diego region—Hertlein and Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2, Pt. 1, p. 59, 1944. “Chula Vista district,”
Pliocene—Hertlein and Grant, Calif. State Div. Mines Bull. 170, chapter 2, p. 60, 1954 (1955). “San Diego formation.”

Type specIMEN: No. 11334, Invertebrate Paleontology Collection, University of California.

Type tocatity: “Santa Ynez River district, Santa Barbara County, California, Univ. Calif.
Loc. 3128.” “Upper Fernando formation, Upper Pliocene.” [According to Woodring (1950, p. 68),
the type apparently came from the “upper Santa Ynez Valley in strata presumably of Careaga age.” ]

Rance: Middle Pliocene in southern California.

OccuRRENCE IN THE SAN D1eGO FORMATION: Soledad Mountain; Swift Canyon near Boundary Street; Las Chollas Val-
ley above Market Street Bridge; “cf.” from road cuts on Alamo Drive and Center Street, north side of upper Las Chollas Valley;
off Cherokee Street, on the right side of canyon in old railway embankment; near corner of Thirty-fifth Street and Market Street
extension, San Diego (all cited by Grant and Hertlein). CartrorntA ACADEMY OF ScrENCEs: Loc. 1177, road cut on west side
of hill just east of corner of Haines Street and Tourmaline Street, Pacific Beach district; Loc. 1543, 1/4 mile east of Fairmount
Avenue, in bottom of canyon just south of Laurel Street; Loc. 28884, embankment on Windsor Drive, where Tourmaline Street
would intersect if projected, Pacific Beach; Loc. 33218, near Maple and Haller streets, San Diego; Loc. 36384, about two feet

(105) Dendraster coalingaensis Twitchell in Clark and Twitchell, U.S. Geol. Surv., Monogr. 54, p. 196, pl. 90, figs. 2a-c,
1915. Upper portion of Etchegoin formation, Pliocene. See also Stewart, R. B., in Woodring, Stewart, and Richards, U.S. Geol.
Sury., Prof. Paper 195, p. 81, pl. 10, figs. 6-9, 10, 11, 12; pl. 39, fig. 7 (“cf.”); pl. 45, figs. 1, 2, 3, 4 (var.), 1941.

(106) Dendraster elsmerensis Durham, Amer. Jour. Sci., Vol. 247, p. 50, fig. 2F, pl. 1, figs. 2, 3, 4, 6, January, 1949. From
“Loc. A4457—apparently in SW/1/, of NE! of Sec. 8, T 3N, R 15W, San Bernardino Base and Meridian. From hillside on
northwest side of stream, about 200 yards upstream from point where contact of Pico formation and basement cross the stream.
Collected from 0’ to 25’ above base of Pico formation. In association with numerous molluscs and Astrodapsis fernandoensis
Pack.”

(107) Dendraster pentagonalis Israelsky, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 11, p. 380, pl. 69, figs.
3, 4a, 4b, November 7, 1923. “Cedros Island, Baja California.” “Pliocene.”

(108) Dibblee, T., Calif. State Div. Mines, Bull. 150, p. 46, 1950.

Votume II] Marine PLIOcENE OF SAN D1EGO, CALIFORNIA 119

above conglomerate at base of San Diego formation in road cut on east side of Cabrillo Freeway nearly opposite Mercy Hospital;
not localized (No. 181, Chas. Sternberg coll.). Los ANGELEs County Museum: Loc. 106, behind house 3030, west side
of Reynard Way, San Diego; Loc. 107, 100-foot bluff with scattered fossiliferous concretions in clay quarry at end of Arroyo
Drive, San Diego; Loc. 123, bluff 100 yards east of Market Street at level of 34th Street (which does not go through at this
point); Loc. 127, shell stratum 5 feet thick, Market Street extension in Encanto, 11/4 miles south of Euclid Avenue, San Diego;
Loc. 176, at south end of Juniper Street, at crossing of 31st Street, turn right on dirt road leading to Wabash Canyon, on both
sides of canyon; Loc. 294, silt back of house No. 3550 Dove Street, San Diego; Loc. 301, exposure of San Diego formation silt,
50 feet long and 10 to 15 feet high, inside east gate of Naval Hospital 4 feet above road (which is parallel to fence), 200
yards west from lowest part of Florida Street, below Balboa Park, San Diego; Loc. 307, near west end of Hayes Avenue if pro-
jected to near road under bridge; Loc. 311B, about 15 feet above base of bluff on recent road cut at Loc. 311A, on Windsor
Drive, Pacific Beach district; Loc. A-2862, “Near San Diego”; east side of 2400 block on Euclid Avenue, San Diego (J. F.
Arndt, coll.); southwest corner of Fairmount and Home avenues, above barnacle bed, also one specimen from barnacle bed, San
Diego. SAN Dieco Society oF Naturat History: Loc. 23, road cut on west side of hill just east of corner of Haines Street
and Tourmaline Street, Pacific Beach district; Loc. 80, south slope of Soledad Mountain, first arroyo west of Rose Canyon high-
way; Loc. 80A, just west of Loc. 80. Also numerous other localities in and near San Diego.

ORIGINAL DESCRIPTION: This is very closely allied to Dendraster ashleyi (Arnold) because of its
wide odd anterior ambulacral petal and great angular divergence of the petals of bivium, but differs
in that the apical system is less eccentric, and in that the test has a more nearly elliptical outline,
the transverse diameter being the greater. Its size is usually larger than that of D. ashleyi. (Kew.)
[The illustration of the type is indicated as approximately natural size and measures approximately

71 mm. in length, 85 mm. in width, 6.5 mm. in height. }

Remarks: The less eccentric apical system and less divergent angle of the bivium can usually
be relied upon to separate this subspecies from typical D. ashleyi. This subspecies often attains a very
large size; one specimen from Las Chollas Valley above Market Street bridge, San Diego, measures
100 mm. in length, 115 mm. in width, and about 9.5 mm, in height.

This subspecies occurs abundantly in the San Diego formation at various localities and is the
echinoid most commonly found in Pliocene beds in the San Diego area.

Through the courtesy of Mr. George P. Kanakoff of the Los Angeles County Museum, we have
had the privilege of examining about 75 specimens of this subspecies collected from Pliocene beds in
and near San Diego. These reveal that there is considerable variation in size of test, in degree of
eccentricity of the apical system, and in size of angle of the bivium. Some of these specimens closely
resemble the form illustrated as D. ashleyi by Woodring (1950, pl. 20, fig. 1), who remarked that they
closely approached the subspecies ynezensis.

A series of 17 specimens of Dendraster was collected by Kanakoff at Loc. 106 (LAM), on the
west side of Reynard Way in San Diego. Seven of these are referable to D. ashleyi and 10 to the
subspecies ynezensis. The average measurements of these were as follows: for D. ashleyi, length
54.5 mm., width 68.2 mm., distance of apical system from posterior end 12.8 mm.; for D. ashleyi
ynezensis, length 58 mm., width 63.1 mm., distance of apical system from posterior end 16.4 mm.

One specimen, 77.5 mm. in length and 86.5 mm. in width, from Loc. 107 (LAM), still retains
many of the spines, especially on the oral side. These spines are about 2.6 to 3 mm. in length. They
are somewhat greater in diameter and a little longer than those of the Recent D. excentricus.

Four specimens from Loc. 294 (LAM) have very thin margins. The apical system is similar to
that of the present subspecies. One small specimen (pl. 22, fig. 2) from this locality has a rounded
outline (length 20.5 mm., width 20.6 mm.) and an eccentric apical system as in large forms of
D. ashleyi ynezensis.

A large specimen, typical of this subspecies, collected by Kanakoff from a bluff east of Market
Street (at level of 34th Street), measures 81 mm. in length, 92 mm. in width, approximately 10 mm.
in height (convexity), with the apical system approximately 22.4 mm. from the posterior margin.

Several specimens of this subspecies, furnished us by E. Dean Milow, were collected about two
feet above the conglomerate at the base of the San Diego formation in a road cut on the east side

of the Cabrillo Freeway nearly opposite Mercy Hospital.

Some specimens from the San Diego area are intermediate between Dendraster ashleyi and the
subspecies ynezensis and could perhaps be referred to either of these forms. However, most specimens
fall into one category or the other.

120 San Dieco Sociery oF Naturat History [Memorrs

Dendraster casseli Grant and Hertlein
Plate 22, Figure 7
Dendraster casseli Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 81, pl. 1, figs. 1-3; pl. 30,

fig. 3, April 19, 1938.

TYPE SPECIMEN: No. 6193, Type Collection, Department of Paleontology, University of Cali-
fornia at Los Angeles.

Type Locauity: “from Loc. 356 (U.C.L.A.), at head of ravine in SE. corner of Sec. 10,
T.4N., R.17W., S.B.B. & M., about 0.2 mi. N. of corner, in the Dendraster bed, elevation 1300 feet
by contour (U. S. Geol. Surv. topog. map of Santa Susana quadrangle).” Los Angeles County,
California. “Upper half of the Pliocene.”

Rance: Middle Pliocene in southern California and San José Island, Gulf of California, Lower
California, Mexico.

OccuRRENCE IN THE SAN DrEGO FORMATION: Los ANGELES CounTy Museum: Loc. 107, 100-foot bluff with scat-
tered concretions in clay quarry at end of Arroyo Drive, San Diego.

ORIGINAL DESCRIPTION: Test of medium size; outline subcircular, the posterior margin more
broadly curved, also slightly more broadly curved at distal ends of the anterior paired ambulacra;
margin thin but dorsal (abactinal) surface inflated, ventral (actinal) surface slightly concave; apical
system slightly excentric posteriorly, and slightly posterior to the highest portion of test, genital pores
4; ambulacra subpetaloid, narrow, long, the poriferous zones gradually becoming obsolete distally,
the nonporiferous zones raised, sometimes conspicuously, sometimes the entire ambulacra raised,
especially the proximal portion; bivial angle but slightly larger than angles between ambulacra of
the trivium; pore-pairs conjugate; primary tubercles imperforate, in depressed scrobicules; ambulacral
furrows but slightly depressed but variable, bifurcating close to the peristome; periproct small, nearly
circular, on actinal surface close to margin. Length of holotype, 50.7 mm.; width, 51.1 mm.; height,
approximately 8.4 mm. (Grant and Hertlein.)

Remarks: The test of Dendraster casseli is characterized by its slightly eccentric apical system
and by its long, narrow, open, and raised ambulacral petals.

Two specimens of this species, their actinal surfaces cemented together by matrix, were collected
by G. P. Kanakoff at Loc. 107 (LAM), at the end of Arroyo Drive in San Diego. The larger of
these measures 56.9 mm. in length, 60.8 mm. in width. The specimens compare favorably with the
type specimen of D. casseli, differing chiefly in that petals I, II, IV, and V are somewhat more con-
tracted at their distal ends. The difference, however, is believed to be individual variation or perhaps
a feature concomitant with the larger size of the specimen.

This is the first record of the occurrence of this species in the San Diego formation. It also is
known to occur in the upper half of the Pliocene section in northern Los Angeles County and in
Pliocene strata on San José Island in the Gulf of California.

Dendraster gibbsii humilis Kew

Plate 22, Figures 5, 9

Dendraster gibbsii humilis Kew, Univ. Calif. Publ. Dept. Geol., Vol. 12, No. 2, p. 124, pl. 25, figs. 3a, 3b, September 28, 1920.
“Coalinga district, Fresno County, California . . . and Santa Maria district, California.”—Grant and Hertlein, Publ.
Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 88, pl. 1, fig. 4, 1938. Also “Pacific Beach, San Diego, California.”

Type specIMEN: No. 11379, Invertebrate Paleontology Collection, University of California.
Type Locauity: “Coalinga district, Fresno County, California, Univ. Calif. Loc. 2100.” [From
“a locality in the Jacalitos Hills west of the Kettleman Hills” according to Stewart, 1941, p. 80. }

Rance: Middle Pliocene in southern California and northern Lower California.

OccuRRENCE IN THE SAN DreGO FORMATION: CALIFORNIA ACADEMY OF SCIENCES: Loc. 12164, Pacific Beach (Grant
and Hertlein).

ORIGINAL DESCRIPTION: This seems to be an intermediate form between Dendraster gibbsii
(Rémond) and D. ashleyi (Arnold), differing from the former in having a thinner test with angulated
margins; from the latter it differs in that the odd anterior petal is narrower, about the same width
as the anterior lateral pair, and in that the apical system is less eccentric. (Kew.)

Votume II] Marine PLIOCENE OF SAN D1EGo, CALIFORNIA 121

Remarks: There is little to be added to the above description. Typical specimens differ from

Dendraster gibbsi"”? in particulars which justify a subspecific name for this form.

This subspecies is known from Pliocene strata at Pacific Beach, San Diego, by two specimens
collected by Henry Hemphill. The apical system of these is not so eccentric as that of the type illustrated
by Kew; but the general outline of the test, the petals that are widely open at the end, and the similarity
in size of the odd anterior petal to the others, all are characters that lead us to refer these specimens
to D. gibbsii humilis.

In addition to its occurrence in Pliocene beds at San Diego, this subspecies has been recorded
as occurring in Pliocene strata in the Coalinga district, the Santa Maria district, and the Purisima
formation in California, and at Cedros Island, at Turtle Bay, and near Scammon Lagoon, Lower
California, Mexico.

Genus MERRIAMASTER Lambert

Merriamaster Lambert, Rev. Crit. Paléozool., Quinzieme année [Vol. 15}, No. 1, p. 64, January, 1911. “Type” of the genus:
“Scutella Perrint Weawer {Weaver].”—Lambert and Thiéry, Essai Nomencl. Raison. Echinid., Fasc. 4, p. 312, 1914,
and Fasc. 9, p. 581, 1925.—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 64, 1938.
“Type of the genus (by original designation and by monotypy): Scutella perrini Weaver.”—Mortensen, Monogr. Echin.
IV.2. Clypeastroida, p. 396, December 30, 1948. “Genotype: Merriamaster Perrini (Weaver).”—Durham, Univ. Calif.
Publ. Geol. Sci., Vol. 31, No. 4, p. 161, 1955. “Type species: of Merriamaster, Scutella perrini Weaver, orig. desig.”

Orchoporus Lambert and Thiéry, Essai Nomencl. Raison, Echinid., Fasc. 4, p. 293, March, 1914. Type by monotypy, sole
species, Orchoporus koehleri Lambert and Thiéry. (New name for Astrodapsis sp. indet., Arnold, U.S. Geol. Surv., Bull.
396, p. 162, pl. 28, figs. 5, 5a, 1909. “Upper Etchegoin formation.” (P. 37) From Loc. 4708 “On 1,245-foot hill
. 4 miles southeast of northwest end of Kettleman Hills, east side of sec. 32, T. 21S., R.17E. Arca bed in upper Mya zone,
or uppermost beds.”) (See also Stewart, in Woodring, Stewart, and Richards, 1941, p. 82.)

?T witchellia Lambert, Rev. Crit. de Paléozool., Vol. 20, No. 4, p. 171, 1916. “. .. . avec deux espéces, T. Merriami Anderson
(Astrodapsis), type du genre (fig. 7) et T. Packi, a pétales courts, l’impair plus ouvert que les autres (fig. 8).” The figures
referred to are by W. B. Clark and Twitchell, U.S. Geol. Surv., Monogr. 54, pl. 85, 1915. Type of the genus (by original
designation, as above): Scutella (?) merriami (Anderson) of W. B. Clark and Twitchell, fig. 7 only. Not Astrodapsis
merriami Anderson, Proc. Calif. Acad. Sci., Ser. 3, Geol., Vol. 2, pp. 193-194, pl. 14, figs. 33, 34, December 4, 1905.

Type species (by original designation) : Scutella perrini Weaver. Reference given to Arnold
and R. Anderson, U. S. Geol. Surv., Bull. 398, pl. 50, figs. 1 and 2, 1910. From Loc. 4712 “east of
Zapato Creek, one-half mile south of Adolph Kreyenhagen’s house, SW. 14 SE. 14 sec. 8, T.22S.,
R.16E. Variable pebbly sand, with many fossils. Pecten coalingaensis zone, or upper middle beds.”
Upper Miocene or lower Pliocene. [Pliocene]. [Scutella perrini Weaver, Univ. Calif. Publ., Bull.
Dept. Geol., Vol. 5, No. 17, p. 273, pl. 12, fig. 2, December 28, 1908. Type locality, “In beds
presumably of Miocene age near Coalinga, California.” [Late Pliocene.} —Grant and Hertlein,
Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 68, pl. 15, fig. 11; pl. 30, fig. 9, 1938.
—Stewart in Woodring, Stewart, and Richards, U. S. Geol. Surv., Prof. Paper 195, p. 81, pl. 46,
figs. 1, 2, 4, 7, 10, 12, 1941. Pecten and Trachycardium zone in Kettleman Hills, San Joaquin County,
California. San Joaquin formation, late Pliocene. —Durham, Univ. Calif. Publ. Geol. Sci., Vol. 31,
No. 4, p. 161, figs. 4f (p. 79), 35¢ (p. 161), 1955. ]

Rance: Middle Pliocene of California and northern Lower California.

DescriPTION: Test ovate, moderately flattened, moderately thick, the margins rounded; genital
pores 4 (none between petals I and V); apical system slightly eccentric posteriorly; ambulacral petals
open and extending to the margin, usually slightly raised; test with large, well-developed tubercles;
ambulacral food grooves on adults bifurcate about one-third the distance from the peristome to the
margin; periproct just inframarginal, often on a slight rostrum; internal radial supports simple, mod-
erately developed; internal concentric supports only slightly developed.

Remarks: A discussion of this genus was given by the present authors in 1938, and recently
Durham gave an extensive discussion of its morphology. Stewart pointed out that the type of Orchoporus

(109) Scutella gibbsii Rémond, Proc. Calif. Acad. Nat. Sci., Vol. 3, p. 13, April, 1863. “Kern Lake, Buena Vista County.”
Gabb cited as considering the species to be of Miocene age. See also Grant and Hertlein, 1938, p. 88, pl. 14, fig. 6, 1938.
Earlier records cited. Also Stewart, in Woodring, Stewart, and Richards, U.S. Geol. Surv., Prof. Paper 195, p. 80, pl. 40, figs.
2-4; pl. 42, figs. 1-5; pl. 43, figs. 1, 2, 4, 5; pl. 44, fig. 6, 1941.

The recorded occurrence of this species at Lituya Bay, Alaska, by Dall (in Mertie, U.S. Geol. Surv., Bull. 836, p. 130,
1931) is referable to a different species, as indicated by Stewart, 1941, p. 109, footnote 32. It has recently been named Echinarach-
nius alaskense by Durham (Jour. Paleo., Vol. 31, No. 3, p. 628, pl. 72, figs. 6, 8, May, 1957.)

122 San Disco Socrery oF Natura History [Memoirs

is a young specimen of Merriamaster perrini, and although the original figure is said to be deceiving,
it appears probable that Twitchellia likewise can be referred to Merriamaster.

Durham (1955) placed Merriamaster in the Dendrasteridae and Astrodapsis in the Echina-
rachniidae. However, Merriamaster appears to be more closely related to Astrodapsis than to Dendraster.
Mortensen (1948, p. 397) mentioned that Merriamaster may probably represent a transition between
Astrodapsis and Dendraster, but he also added that “in some cases of the very numerous species of
this group from the American west coast it may be questionable to which of the three said genera they

should be referred.”

The test of Merriamaster differs from that of Astrodapsis in the slightly eccentric apical
system, in the somewhat shorter and generally less elevated petals, and in the bifurcation of the food
grooves about one-third the distance from the peristome to the margin. In Astrodapsis the apical system
is central, the petals are decidedly raised above the surface, and the central food grooves extend
unbranched to the margin.

(110)

Merriamaster differs from Dendraster in the less eccentric apical system, the more open and usually
raised petals, the thicker and more rounded margins, the fewer interior concentric supports, the greater
number of plates on the oral surface, and the usually larger spine bases.

Only five or possibly six species in California and Lower California appear to be referable to
the genus Merriamaster. Two of these occur in Pliocene beds in the San Diego area. In the San
Joaquin Valley this genus is known to occur only in the San Joaquin formation of late Pliocene age.
The genus Merriamaster is not definitely known to occur in western North America north of Half-
moon Bay, California.

KEY TO THE SPECIES OF MERRIAMASTER
A. Outline subpentagonal; petals rather narrow and decidedly elevated at and near apex; shallow

interambulacral depressions present on abactinal surface; tubercles rather small _...........--...-------- pacificus
B. Outline broadly oval; petals moderately broad and only slightly elevated; interambulacral
depressions on abactinal surface only slightly developed; tubercles large.........-----.-.----1--+s+1ssseeeeesen israelskyi

Merriamaster cf. M. israelskyi E. K. Jordan and Hertlein
Plate 23, Figures 10, 12, 14

The original reference to typical M. israelskyi is Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14,
p. 424, pl. 27, figs. 4, 6, July 22, 1926.

Astrodapsis israelskyi E. K. Jordan and Hertlein, Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol.
2, p. 73, 1938. “lower beds in the Pliocene at Pacific Beach, San Diego”; “Cabrillo Canyon, Balboa Park, San Diego.”

Type speciMEN: No. 2086, Type Collection, Department of Geology, California Academy of
Sciences.
Type tocauity: “Bernstein’s abalone camp, Cedros Island, Lower California; upper Pliocene.”

Rance: Middle Pliocene in southern California, and Cedros Island and Turtle Bay, Lower

California, Mexico.

OccurRENCE IN THE SAN D1EGo FORMATION: Los ANGELES County Museum: (cf.) Loc. 107, 100-foot bluff with
scattered fossiliferous concretions in clay quarry at end of Arroyo Drive, San Diego; Loc. 122, 20 to 30 feet below end of
Loring Street, Pacific Beach; Loc. 124, 15 feet below floor level of Snyder Continuation school, San Diego. SAN DrEGo So-
crery or Natura History: Cabrillo Canyon, Balboa Park, San Diego.

ORIGINAL DESCRIPTION of A. israelskyi: Test small; subcircular to oval in outline, not greatly
elevated, the upper surface rather flat; margin thick, evenly rounded and entire; apical system central,
or slightly posterior, the apex of the test slightly anterior to the center of the madreporic area; madreporic
area pentagonal, with four genital pores; petals narrow, slightly elevated, widely open, and extending
nearly to the margin; rows of pores at first diverge, then at about half the distance to the margin they

(110) Astrodapsis Conrad, Proc. Acad. Nat. Sci. Philadelphia, Vol. 8, No. 6, p. 315, apparently issued approximately
April 25, 1957. Only species cited, Astrodapsis antiselli Conrad. “Monterey Co., Cal.” Middle Tertiary. Illustrated by Conrad,
U.S. Pac. R.R. Repts., Vol. 7, Palaeo., p. 196, pl. 10, figs. 1, 2, 1857. “Estrella” [Monterey County}, California.—Richards,
Trans. San Diego Soc. Nat. Hist., Vol. 8, No. 9, pl. 7, figs. la, 1b, 1935. (Type specimen illustrated ).—Grant and Hertlein,
Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 70, pl. 16, figs. 3, 4, 1938.—Durham, Univ. Calif. Publ. Geol.
Sci., Vol. 31, No. 4, pp. 104, 167, fig. 3d (p. 78), fig. 22a (p. 105), 1955.

Vo.umeE II] Marine PLIOCENE OF SAN D1EGO, CALIFORNIA 123

converge slightly, after which they continue toward the margin parallel or very slightly divergent;
outer row of pores more pronouncedly sinuous than inner; interambulacral areas relatively broad, little
depressed, flat, sloping gently from the apex toward the margin; inferior surface concave toward the
center; mouth central, large, subpentagonal in outline; ambulacral furrows not distinct, but branching
close to their origin at the peristome and extending nearly to the margin; periproct fairly large, situated
on ventral surface and a little less than its own diameter from the margin; tuberculation prominent,
the tubercles rather large and distantly spaced, those on the inferior surface perhaps even more prominent
than those above. Anteroposterior diameter 37.5 mm.; transverse diameter 35.3 mm.; greatest elevation
7.9 mm. (E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 424, pl. 27,
figs. 4, 6, July 22, 1926.)

Remarks: The authors of this species recognized its general relationship to “Dendraster” perrini,
the type species of Merriamaster. Study of a series of specimens of “Astrodapsis” israelskyi leads the
present authors to place it in the genus Merriamaster. This assignment is based upon the slight eccen-
tricity of the apical system and especially on the fact that the central food grooves on the oral surface
of the test do not extend to the margin but branch about a third the distance from the peristome to
the margin. Assuming that bifurcation of the food grooves is a generic character of Merriamaster,
Astrodapsis kewi E. K. Jordan and Hertlein'’’ also belongs in Merriamaster.

The specimens from San Diego referred to Merriamaster cf. M. israelskyi range in length from
about 25 mm. to 43.3 mm. None of these are perfectly preserved; but in observable characters these
specimens agree in general with the type of this species, and they closely resemble specimens from San
Bartolomé Bay (Turtle Bay), Lower California.

In two specimens from Balboa Park in the collection of the San Diego Society of Natural History,
the larger one 43.3 mm. long and 43.4 mm. wide, the actinal surface is moderately well exposed. In
outline of test, character of tubercles, and thickness of margin, these specimens are similar to M. israelskyi.

Four imperfect and about a dozen smaller and quite imperfect specimens of Merriamaster were
collected by George Kanakoff at Loc. 124 (LAM), with specimens of M. cf. M. israelskyi. The greatest
diameter measurable among these is 71.8 mm. The outline, the moderately thick margins, and the
tuberculation on the oral surface, where observable, do not differ greatly from those of M. israelskyi.
The incompleteness and poor preservation of these specimens prevent positive identification. It is
possible that some of these might be referable to M. pacificus. Specimens from other localities in San
Diego, none of them well preserved, appear to be referable to M. cf. M. israelskyi.

Merriamaster israelskyi differs from M. pacificus in the ovate rather than subpentagonal outline of
the test, the broader less elevated petals, the coarser tuberculation, the slightly thicker margins, and
the very slight development of the interambulacral depressions on the aboral surface.

In an earlier paper we mentioned the possibility that Smith’s record of Astrodapsis fernandoensis
in the “San Diego” region might be referable to M. israelskyi or to M. pacificus" He

In Merriamaster israelskyi the apical system is almost central in the type specimen and in most
others and the margin is moderately thick, whereas in M. perrini the apical system is moderately
eccentric and the margin is very thick. The ovate outline and much less eccentric apical system separate

M. israelskyi from M. arnoldi Twitchell),

(111) Astrodapsis kewi E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 425, pl. 27, figs. 2,
3, July 22, 1926. “Bernstein’s abalone camp, Cedros Island, Lower California; upper Pliocene.”

(112) “Smith (1916, p. 38) recorded the geologic occurrence of A. fernandoensis as ‘San Diego and Lower Fernando for-
mations of the coastal regions of Southern California’ but we have not seen any specimens of this species in any of the collec-
tions from the San Diego Pliocene available to us. Possibly Smith’s record was based upon imperfect specimens of Astrodapsis
israelskyi or Merriamaster pacificus which have been discovered there since Smith’s paper was issued.”’ (Grant and Hertlein, 1938,
p. 73, footnote. )

(113) Dendraster arnoldi Twitchell, U.S. Geol. Surv., Monogr. 54, pp. 192-193, pl. 88, figs. 4a-d, 1915. “Near A. Kreyen-
hagen’s place and south of Lucille well, 2 miles southwest of Coalinga in Coalinga district, California.” “Etchegoin formation,”
Pliocene.—Stewart in Woodring, Stewart, and Richards, U.S. Geol. Surv., Prof. Paper 195, p. 81, pl. 39, fig. 5; pl. 41, fig. 3;
pl. 46, figs. 3, 5, 6, 8, (cf.) 9, 11, (cf.) 13, 1941 (as Dendraster (Merriamaster) arnoldi). According to Stewart, “Kew’s D.
coalingaensis Twitchell is D. (Merriamaster) arnoldi Twitchell.”

124 San Disco Soctery oF Natura History [Memorrs

Merriamaster pacificus Kew

Plate 23, Figures 1-6, 11; Plate 25, Figure 6; Plate 26, Figure 11

Dendraster pacificus Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 12, No. 2, list opp. p. 52, p. 128, pl. 33, figs. la-c, Septem-
ber 28, 1920. “Cedros Island, Lower California; Pacific Beach, San Diego County, California.” “San Diego formation,
Upper Pliocene.” —E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 420, 1926. “Pliocene of
Pacific Beach” (Kew’s record.)

Merriamaster pacificus Kew, Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 67, pl. 20, fig. 9,
1938. “Pacific Beach, San Diego”; and “Cabrillo Canyon, San Diego.”—Hertlein and Grant, Calif. Jour. Mines and
Geol., Rept. 35 of State Mineralogist, p. 70, 1939. “Cabrillo Canyon,” “San Diego formation,” Pliocene—Hertlein and
Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2, p. 59, 1944. “Cabrillo Canyon,” San Diego, Pliocene——Woodring, U.S.
Geol. Surv., Prof. Paper 222, p. 104, “Pacific Beach and inland,” p. 106, “San Diego district,’ “San Diego formation,”
1950.—Hertlein and Grant, Calif. State Div. Mines, Bull. 170, chapter 2, p. 60, 1954. “San Diego formation.”

Dendraster eens) pacificus Kew, Woodring, Stewart, and Richards, U.S. Geol. Surv., Prof. Paper 195, p. 113, 1941.
“Pacific Beach.”

TYPE SPECIMEN: Holotype‘''*) No. 448, Type Collection, Department of Geology, California
Academy of Sciences.

Type Locauity: “Pacific Beach, San Diego County, California.” “San Diego formation, Upper
Pliocene.”

Rance: Middle Pliocene in southern California and northern Lower California.

OccurRRENCE IN THE SAN DrEGO FORMATION: Pacific Beach (Kew; E. K. Jordan and Hertlein; Grant and Hertlein);
Cabrillo Canyon, Balboa Park, San Diego; Pacific Beach and inland (Woodring). Los ANGELES County Museum: Loc.
122, 20 to 30 feet below end of Loring Street, Pacific Beach; Loc. 308, 0.2 mile north of intersection of Harbor Drive and
Tourmaline Street, Pacific Beach; Loc. 309, northwest of Chalcedony Street, gully in second canyon east of Kate Sessions School,
Pacific Beach. UNiverstry OF CALIFORNIA: Loc. 3069, 14 mile north of Crystal Road, near top of cliff just below heavy con-
glomerate bed, Pacific Beach (L. Phillips coll.).

ORIGINAL DESCRIPTION: Test small. Average measurements of holotype: anteroposterior diameter
36 mm., transverse diameter 35 mm., greatest height 8.3 mm. Outline subpentagonal. Upper surface
depressed, and rising gently from a moderately thickened and rounded margin to a low apex situated
slightly anterior to the center of the test. Very indistinct depressions are present in the interambulacral
areas. Apical system slightly eccentric to the posterior. Petals of the trivium of the same length and
longer than those of the bivium, extending a little over half the distance from the apical system to the
margin. Rows of pores diverge for about one-half the length of the petal and then continue in parallel
lines to the end, the outer rows converging but little in the distal portion of the petal; a few sporadic
pores extend beyond nearly to the edge of the test. Odd anterior petal is slightly narrower than the
lateral petals. Petals are more or less elevated, this being a distinctive character. Four large genital
pores and five perforated radial plates are present in the apical system. Lower surface concave to the
peristome; the latter is subcircular in outline and posterior to the center of the test, being opposite
the apical system. Distinct, broad ambulacral furrows present, branching dichotomously a short
distance from the mouth and continuing to the margin. Tuberculation prominent; consists of a few
large scrobicular tubercles on the petals; smaller secondary tubercles are present over the remainder
of the upper surface, interspaced with numerous milliaries; the under side is covered by a few large
tubercles of the same size as on the petals, and interspaced with numerous smaller ones. Periproct
round, inframarginal, and situated a distance about equal to its own diameter from the edge of the

test. (Kew.)

Remarks: Diagnostic features of this species are the pentagonal outline, the slightly eccentric
apical system, the narrow petals, decidedly raised near the apex, and the shallow interambulacral
depressions on the aboral surface.

A series of 14 specimens collected by J. F. Arndt at Loc. 122 (LAM), Pacific Beach, range from
20 to 33.8 mm. in maximum diameter. Most of these are slightly crushed or imperfect; but all have
the outline, shape and height of petals, and other characters of Merriamaster pacificus. A series of 25
specimens collected by Mr. G. P. Kanakoff at Loc. 308 (LAM), 0.2 mile north of the intersection
of Harbor Boulevard and Tourmaline Street, Pacific Beach, range from 18 to 38.6 mm. in maximum
diameter. Some of these are quite well preserved and are typical of this species.

(114) Two “Cotypes” were originally cited: No. 448, Department of Geology Type Collection, California Academy of
Sciences, and No. 11340, Invertebrate Paleontology Collection, University of California. Measurements of the “holotype” also
were given. These measurements agree with those of the specimen illustrated as ““Cotype” No. 448, and therefore it is here selected
as the holotype.

Vovume IT] Marine PLIocENE OF SAN D1EGo, CALIFORNIA 125

Most of the other specimens of this species that we have seen from San Diego, except the holotype,
are poorly preserved and furnish no additional information concerning this species.

A specimen in the collections of the San Diego Society of Natural History collected at Pacific
Beach by Frank Stephens measures 25.5 mm. in length, 27.4 mm. in width, 7.8 mm. in height. The
oral surface is encrusted with sediment, but the position of the apical system and shape of the petals
are those of M. pacificus. Two specimens from Cabrillo Canyon in San Diego, in the collections of
the same institution, are tentatively referred to M. pacificus on the basis of their subpentagonal outline
and somewhat flattened margins.

A specimen from Loc. 124 (LAM), 15 feet below the floor level of Snyder Continuation School
in San Diego, is 35 mm. in diameter. It is imperfectly preserved, but the general outline of the apical
system is that of the present species. However, it may be referable to M. cf. M. israelskyi which occurs
at that locality.

So far as is known, Merriamaster pacificus is restricted to the San Diego horizon or to beds of
approximately that age in southern California and at Cedros Island, Lower California. The record
cited by Argamakova'"!”) of the present species in the Nutovo series, late Pliocene, on Sakhalin Island,
Russia, needs confirmation.

Family MELLITIDAE Stefanini

Medium-sized to large, flattened; well-developed internal supports; posterior interambulacral and
paired ambulacral lunules or indentations; petals well defined, moderately closed; pores conjugate, outer
member of pore-pair elongated, a few primary pore-pairs outside petals; paired interambulacra not in
contact with basicoronal plates on oral surface; interambulacra on oral surface widening toward ambitus,
about as wide as ambulacra at ambitus; basicoronal plates fairly small, interambulacral plates slightly
larger than ambulacral plates; periproct on oral surface between posterior interambulacral lunule and
peristome; ambulacral food grooves bifurcating just outside basicoronal plates. (Durham, 1955.) Early
Miocene to Recent. Recent along tropical and warm temperate coasts of the Americas.

REMARKS: Two genera, Encope L. Agassiz and Mellita L. Agassiz, in this family, with 5 marginal
lunules or notches, are known from the late Tertiary of California. Scutaster Pack, with 3 lunules,
formerly included in this family, was recently placed in the family Scutasteridae by Durham, 1955.

Genus ENCOPE L. Agassiz

Encope L. Agassiz, Cat. Ectyp. Echin., pp. 6, 17, 1840. Sole species: “grandis Ag. . . . (Species viva.) Martinique.” —L. Agassiz,
Monogr. Echin. Viv. Foss., Seconde Monogr. Scutel., p. 45, 1841—C. W. Cooke, Jour. Paleo., Vol. 16, No. 1, p. 19,
1942. “Genotype, Encope grandis Agassiz.”—Mortensen, Monogr. Echin., IV.2. Clypeastroida, p. 433, 1948. “Genotype:
Encope grandis L. Agassiz.” —Durham, Geol. Soc. Amer., Mem. 43, Pt. 2, p. 42, 1950.” Genotype: Encope grandis
Agassiz (monotypic)”—Durham, Univ. Calif. Publ. Geol. Sci., Vol. 31, No. 4, p. 174, November 21, 1955. “Type
species: of Encope, E. grandis L. Agassiz, monotypic.”

Moulinia L. Agassiz, Monogr. Echin., Seconde Monogr. Scutel., pp. 3, 139, 1841. Sole species: “Moulinia cassidulina Ag.”,
pl. 22, figs. 1-6, 1841. From “cotes de la Martinique.” [According to A. Agassiz, Mem. Mus. Comp. Zool., Vol. 3, pp.
326-328, 1872, and Mortensen, 1948, p. 435, this is “only a developmental stage of Encope (emarginata)”’}.

Moulinsia L. Agassiz in L. Agassiz and Desor, Ann. Sci. Nat. (Zool.), Ser. 3, Vol. 7, p. 139, 1847. For Moulinia L. Agassiz,
1841.

Echinoglyphus Van Phelsum, Gray, Proc. Zool. Soc. London for 1851, p. 37, October 28, 1852. “The Encope of Agassiz.”

Echinoglycus Van Phelsum, Gray, Cat. Rec. Echin. Brit. Mus., Pt. 1, p. 24, 1855. Several species cited, including Encope
grandis L. Agassiz.

Not Echinoglycus Van Phelsum, L. Agassiz, 1841. Type (designated by Durham, 1955, p. 175): Echinoglycus irregularis Leske
{=Echinodiscus bisperforatus Leske.}

Ravenellia Liitken, Vidensk. Meddel. Nat. For. Kjébenhavn for 1863, p. 168 (100), 1863. Type by monotypy: Scutella macro-
phora Ravenel.

Not Ravenelia McCrady, 1859.

Macrophora Conrad, Proc. Acad. Nat. Sci. Philadelphia, Vol. 17, No. 2, p. 74, 1865. Species cited: “M. macrophora, (Scutella),
Ravenel” and “M. raveneli, C.” [Scutella macrophora Ravenel, type by tautonymy. Described in Proc. Acad. Nat. Sci.
Philadelphia, Vol. 1, p. 81, 1841. “found in calcareous deposite upon my plantation on Cooper River, in St. Thomas’s
Parish, about 17 miles from Charleston.” South Carolina. Pliocene. ]

Desmoulinaster Lambert and Thiéry, Essai Nomencl. raisonnée Echin., Fasc. 4, p. 294, March, 1914. New name for Moulinia
L. Agassiz, 1841 “(barbarisme)” and Moulinsia L. Agassiz, 1847, (not Moulinsia Grateloup, 1840). “Type unique: D.
cassidulinus Desmoulins (Scutella)” ...

(115) Argamakova, V. F., Trans. Oil Geol. Inst., Ser. A, Fasc. 41, pp. 27, 41, pl. 1, fig. 6, 1934. On the right side of
Great-Uini River, Sakhalin Island, Russia. Nutovo series, late Pliocene.

126 San Dreco Society or Naturat History [Memoirs

Tyee species (by monotypy) : “grandis Ag. . . . (Species viva.) Martinique.” [Described by L.
Agassiz, Monogr. Echin., Seconde Monogr. Scutel., p. 57, pl. 6, figs. 1-9, 1841. “. . . provient
probablement des Antilles.” —A. Agassiz, Illustr. Cat. Mus. Comp. Zool., No. 7 (Mem. Mus. Comp.
Zool., Vol 3), Pt. 1, p. 127, 1872; Pt. 3, p. 545, pl. 13d, figs. 5, 6, 1873. Gulf of California. —Morten-
sen, Monogr. Echin. IV.2. Clypeastroida, p. 437, pl. 63, figs. 1, 2, 1948. ]

Rance: Early Miocene to Recent. Recent in tropical and subtropical waters on the east and
west coasts of the Americas, from the intertidal zone to about 130 meters (71 fathoms), but usually in
less than 50 meters (27 fathoms).

DEscrIPTION: Test stout, with a posterior interambulacral lunule, and with marginal notches or
slits or lunules in two or more of the ambulacra; genital pores 5. (H. L. Clark, 1925.)

Remarks: This genus is known to occur both living and fossil on the east and west coasts of the
Americas. Durham (1950) recorded 13 species and subspecies from Pliocene and Pleistocene strata
in the Gulf of California region. It is known to occur in Pleistocene beds at Magdalena Bay, Lower
California. The present record of Encope in beds of Pliocene age at San Diego is the first record
of its occurrence in late Tertiary strata of the coastal region of California. The occurrence of Encope
has been known for years in the Pliocene beds in Imperial County, California, near the head of the

Gulf of California.

Several species and subspecies have been described by A. H. Clark (1946) and H. L. Clark
(1948) as occurring in tropical and subtropical waters of the western Americas, abundantly in the Gulf
of California and south to northern Peru; but Mortensen (1948) recognized only 8 of these as valid.

Dimensions of a large specimen of the genus Encope taken at the Galapagos Islands are given by H. L.
Clark (1948) as 150 and 155 mm.

Mellita L. Agassiz, which has 4 rather than 5 genital pores, has already been recorded by the
present authors (1938, pp. 101-103) from the Temblor beds of middle Miocene age in California and
from Pleistocene sediment at San Diego and Newport Beach. J. P. Smith (1919, p. 131) also cited the
occurrence of this genus in the Quaternary of southern California, as have several authors subsequently.

Encope tenuis Kew
Plate 23, Figures 7, 13; Plate 24, Figure 11; Plate 25, Figure 4

Encope tenuis Kew, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 8, No. 5, p. 47, pl. 1, fig. 1; pl. 2, fig. 1, April 16, 1914.—
Kew, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 12, No. 2, p. 136, pl. 36, fig. 1; pl. 37, figs. 1a, 1b, September 28,
1920. “Coyote Mountain, Imperial County, California.” “Lower Division of the Carrizo Creek beds, Pliocene.”

Type SPECIMEN: “Cotypes” Numbers 10050 and 10051, Invertebrate Paleontology Collection,
University of California.

Type Locauity: “Lower Division of the Carrizo formation at Coyote Mountain and Carrizo
Valley,” California. “Pliocene.” {Coyote Mountain, only, cited by Kew, 1920. |

Rance: Middle Pliocene in southern California and in Lower California, Mexico.

OccuURRENCE IN THE SAN DreGo FORMATION: Los ANGELES County Museum: Loc. 107, 100-foot bluff with scat-
tered fossiliferous concretions in clay quarry at end of Arroyo Drive, San Diego. SAN D1eco Society or Naturat History:
31st Street and Logan Avenue in San Diego.

ORIGINAL DESCRIPTION: Test broad, transverse diameter sometimes greater than the antero-
posterior diameter. Greatest width posterior to the center. Test thin, with sharply angular margin.
Summit posterior to apical sysem and immediately anterior to interambulacral lunule or foramen.
Area immediately surrounding the lunule somewhat tumid. Ambulacral notches broad, deep, con-
tracting slightly near the margin of the test and tending to close. Both interambulacral lunule and
ambulacral notches varying somewhat in size. Apical system central. Petals nearly closed, and reaching
about two-thirds the distance to the margin. Petals rather narrow. The two lateral petals of the
trivium broader and averaging nine per cent shorter than the others. Interporiferous areas slightly
lenticular, and at widest part about same dimensions as the poriferous area. Actinal side flat, and
marked by deep ambulacral furrows which branch immediately from the peristome and a second time
a short distance from the outer margin. The main furrows are broad, shallow and straight, deepening

VotumeE IT] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 127

as the ambulacral notches are approached. Mouth small and not sunken. Anus situated on the inferior
surface slightly anterior to the interambulacral lunule. (Kew.)

Measurements of figured specimens: of No. 10050, anteroposterior diameter, 92.7 mm., transverse
diameter, 96.0 mm., greatest thickness, 10.3 mm.; of No. 10051, anteroposterior diameter, 110.9 mm.,
transverse diameter, 105.8 mm. (Kew.)

Remarks: Two specimens of this species are represented in collections from the San Diego
formation. The larger and more nearly complete specimen was collected by George Kanakoff at
Loc. 107 (LAM), at the end of Arroyo Drive, San Diego. It measures 104.5 mm. in anteroposterior
diameter, 97 mm. in transverse diameter (incomplete), and 12 mm. in height. One specimen in the
collection of the San Diego Society of Natural History was collected by Mrs. L. D. Bonnet, San
Diego, at 31st Street and Logan Avenue in that city. This specimen is fairly well preserved, but
the margins are mostly incomplete. It is approximately 74 mm. in anteroposterior diameter.

The specimen in the collections of the San Diego Society of Natural History has adhering to it
some gray micaceous silty sandstone, typical of the San Diego formation. Adhering to the specimen
collected by Kanakoff is a slight amount of yellowish-gray sediment similar to that at the end of
Arroyo Drive. It appears, then, that there is no reason to doubt the occurrence of this species in the
San Diego formation. This record is in harmony with that of Lovenia hemphilli, which also occurs in
the San Diego formation and in Pliocene strata in the Gulf of California region.

We compared specimens from San Diego with several specimens from Pliocene beds at Loc. 680
(CAS), Alverson Canyon, Coyote Mountain, Imperial County, California, identified as Encope tenuis
by Merle C. Israelsky: no essential differences are evident. The test of this species is known to be
somewhat variable. The specimens from Imperial County vary in the shape of the interambulacral
lunule and in the distance it extends anteriorly beyond the posterior ends of the bivium.

Characteristic of Encope tenuis are the very thin margins, the shape of the test, highest posteriorly,
and the posterior position of the interambulacral lunule relative to the bivium. The very thin margins
and the open ambulacral notches distinguish Encope tenuis from the Recent E. californica Verrill'®,
in which the openings are usually in the form of closed lunules.

Smith"'”) mentioned the occurrence of E. tenuis in the fauna of “Carrizo (Imperial Co., Calif.,
and Cerros Island, Lower California, lat. 33° N. —28°N.).” However, this record probably refers
only to the occurrence of E. tenuis in Imperial County, which he indicated on another page (page 150).
Beal''®) mentioned “Encope sp. aff. E. tenuis” from the Pliocene Salada formation, 1 kilometer north
of Rancho Conejo in the La Paz Quadrangle in south central Lower California.

Encope loretoensis Durham'''®), described from Pliocene beds at Arroyo de Gua on the east
coast of Lower California, was said to differ from E. tenuis in that about two-thirds of the inter-
ambulacral lunule extends anterior to a line connecting the ends of the bivium. In E. tenuis, as men-
tioned above, the anterior extent of the lunule is quite variable. In view of the variation it appears
doubtful whether E. loretoensis should be assigned more than subspecific status.

Encope tenuis, E. loretoensis, and E. californica are members of a group which apparently is
represented in the Caribbean by such forms as E. michelini L. Agassiz and E. emarginata Leske.

(116) Encope californica Verrill, Amer. Jour. Sci., Ser. 2, Vol. 49, p. 97, January, 1870. “La Paz” and “Cape St. Lucas”
in the “Gulf of California.” Recent—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 96, pl.
11, fig. 4; pl. 30, fig. 2, 1938. Pleistocene and Recent.

(117) Smith, J. P., Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, pp. 149, 154, 1919.

(118) Beal, C. H., “Reconnaissance of the Geology and Oil Possibilities of Baja California, Mexico,” Geol. Soc. Amer.,
Mem. 31, p. 81, 1948.

(119) Encope loretoensis Durham, Geol. Soc. Amer., Mem. 43, Prt. 2, p. 46, pl. 37, fig. 4; pl. 41, figs. 1, 4, 5, August 10,
1950. Loc. A-3552 (UC), an echinoid-pecten bed just above Loc. A 3551, which is, “Lower Pliocene, Arroyo de Gua, north of

Loreto, Lower California. On north side of arroyo, about a quarter of a mile below point where road passes over divide into
Arroyo de Arce. A 2-foot zone of echinoids interbedded in sandstones and conglomerates.”

128 San Dieco Society oF NaTurAL History [Memotrs

Order SPATANGOIDA Claus
Family SPATANGIDAE Gray

Peristome transversely elongated; some or all of the ambulacra more or less petaloid, or more or
less sunken, or both; subanal fasciole present. (H. L. Clark, 1925.) Paleogene to Recent. (Durham
and Melville.)

Genus SPATANGUS Gray

Spatagus O. F. Miiller, Prod. Zool. Danicae, p. 236, 1776. Species listed: S. purpureus [Miiller] and S. pusillus {Miiler].

Spatangus Klein, Gray, Ann. Philos., Vol. 26, p. 430, 1825. Sole species: “S. purpureus, Leske, t.43, £.3,5; t.45,f.5.’—Morten-
sen, Monogr. Echin. V.2. Spatangoida, II, p. 6, December 20, 1951. “Genotype: Spatangus purpureus O. Fr. Miller.”

Not Spatangus Klein, Nat. Dispositio Echin. p. 33, 1734 (pre-Linnaean).

Prospatangus Lambert, Mem. Soc. Géol. France, Paléon., Vol. 9, Fasc. 3, Mém. 24, p. 55, 1902.—Lambert and Thiéry, Essai
Nomencl. Raison. Echinid., Fasc. 6, 7, p. 459, December, 1924. “Type: P. purpureus Miller (Spatangus), vivant des
mers d’Europe.”

Spatangus O. F. Miiller, H. L. Clark, Mem. Mus. Comp. Zool., Vol. 46, No. 2, p. 233, 1917. “Type, Spatangus purpureus
O. F. Miiller, 1776.”—Grant and Hertlein, Publ. Uniy. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 131, 1938. “Type
of the genus (designated by H. L. Clark, . . . 1917): Spatangus purpureus O. F. Miller.”

Type species (designated by H. L. Clark, Mem. Mus. Comp. Zool., Vol. 46, p. 233, 1917,
“Type, Spatangus purpureus O. F. Miiller, 1776”; and Spatangus Gray with the type species, Spatagus
purpureus O. F. Miller, placed on the Official List of Generic Names in Zoology in Opinion 209 of
the International Commission on Zoological Nomenclature, March 8, 1954) : Spatagus purpureus O. F.
Miller [Prod. Zool. Dan., p. 236, 1776. Denmark and adjacent regions. Figured by A. Agassiz,
Illustr. Cat. Mus. Comp. Zool. No. 7 (Mem. Mus. Comp. Zool., Vol. 3), Pt. 3, p. 565, pl. 11f,
figs. 19-22; pl. 14a, fig. 1; pl. 19c, figs. 5, 6; pl. 26, figs. 24-27; pl. 32, figs. 17, 18; pl. 34, figs. 3, 4;
pl. 37, fig. 16; pl. 38, figs. 34, 35, 1873. “Norway; Mediterranean.” —Mortensen, Danish Ingolf-
Exped., Vol. 4, Pt. 2, Echin. (2), pp. 123-129, pl. 2, figs. 8, 12, 14, 16; pl. 16, figs. 1-2, 5-10, 22, 24-25,
27, 29, 31-32, 34, 1907. North Sea, Faroe Island, etc. See also Mortensen, 1951, pp. 10-14, for
synonymy and discussion of this species. } ;

Rance: Eocene to Recent. Bathymetric range of Recent species usually from 50 to 1000 meters
(27 to 547 fathoms), one species (S. raschi Lovén) to a depth of 1472 meters (805 fathoms).

Description: Peripetalous fasciole wanting; sternum well developed, much longer than wide,
fully covered with tubercles; at least ten distal pore-pairs developed in anterior series of Petals II and IV;
genital pores four. (H. L. Clark, 1925.)

Remarks: In the eastern Pacific this genus, with heart-shaped test, occurs chiefly in shallow
waters of the northern hemisphere; but in the eastern Atlantic it ranges south to the Cape of Good
Hope and in the south Pacific to New Zealand, occasionally to a depth of 1472 meters (805 fathoms).
Ten Recent species were included in this genus by Mortensen. The only Recent species of western
North America, Spatangus californicus H. L. Clark, occurs from Cordell Bank, California, to San
Francisquito Bay in the Gulf of California at depths ranging from 64 to 412 meters (35 to 225 fathoms).
Three species of this genus have been described from the Tertiary of California, Spatangus pachecoensis
Pack and S. tapinus Schenck from strata of Eocene age and S. rarus Israelsky from strata of Pliocene age.

Spatangus rarus Israelsky
Plate 25, Figures 1-3

Spatangus rarus Israelsky, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 11, p. 383, pl. 73, figs. la-lc, November 7,
1923,—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 132, pl. 10, fig. 6, 1938. “Pliocene.
—Pacific Beach, San Diego, California (Israelsky).”

Type sPECIMEN: Holotype No. 917, Department of Geology, California Academy of Sciences.
Type Locauity: “Pacific Beach, San Diego, California.” “Pliocene.”

RANGE: Known only from the type locality.

OccurRENCE IN THE SAN Deco FORMATION: CALIFORNIA ACADEMY OF Scrences: Loc. 547, Pacific Beach (Israelsky;
Grant and Hertlein). Los ANGELES County Museum: Loc. 122, 20-30 feet below the end of Loring Street, Pacific Beach.

ORIGINAL DESCRIPTION: Marginal outline of the test nearly circular, notched anteriorly, shallowly
truncated posteriorly. Abactinal surface somewhat elevated, gently arched, greatest height of test

VotumeE II] MarInE PLIOCENE OF SAN D1EGO, CALIFORNIA 129

anterior to the apical system which is subcentral. Petals paired, slightly sunken below general surface
of test; pores paired, about 1 mm. apart and zygose. Odd anterior ambulacrum non-petaloid, lying
wholly in groove which extends from ambitus to the apical system. Antero-lateral ambulacra petaloid,
with petal outlines somewhat convex to the anterior and being nearly straight lines posteriorly; petals
terminated about two-thirds the distance from the apex to the ambitus; ambulacra widen rapidly below
petals. Posterior ambulacra petaloid, somewhat longer than the anterior, both poriferous areas concave
toward a medial line; petals reach three-fifths of distance to ambitus from apex. Peristome anterior.
Periproct with major diameter transverse (width 12 mm., height 6 mm.), elliptical in outline and lying
close to upper edge of posterior truncation. Large tubercles scrobiculate, occurring only in interambu-
lacral areas; most numerous in anterior interambulacral areas in the anterior portions; five primary
tubercles in the anterior row of plates of the posterior paired interambulacrals; only one in the posterior
plate row of the same areas; several also occur along the crest of the ridge in the posterior inter-
ambulacrum. Granules found over the whole of test. Measurements: Length, 72.5 mm.; width,
77.0 mm.; height, 29.3 mm. (Israelsky.)

RemarKS: In addition to the type specimen of Spatangus rarus, we have examined two imperfect
specimens, the larger 82 mm. in length, from Loc. 122 (LAM), Pacific Beach, San Diego; but these

add no new information concerning this species.

Israelsky mentioned that this species more closely resembles some of the species from the late
Tertiary of Europe, especially Spatangus corsicus Desor''*”) than it does the Recent west American
aby (9) Bey Sspeeialy, §
S. californicus H. L. Clark?"

A form from the Miocene of western Ukraine described by Szérényi''”?) has wide ambulacral
petals reminiscent of Spatangus rarus; but it differs somewhat in shape, and the apical system appears
to be more anteriorly placed.

Family LOVENIIDAE Lambert, emended Mortensen

Differs from all other Spatangoids by the presence of an “inner” or “internal” fasciole, surrounding
only the frontal ambulacrum and the apical system. (Mortensen, 1951.) Paleogene to Recent.
(Durham and Melville.)

Genus LOVENIA Desor

Lovenia Desor in L. Agassiz and Desor, Ann. Sci. Nat. (Zool.), Ser. 3, Vol. 6, pl. 16, fig. 16; Vol. 8, pp. 10, 11, July, 1847.
—H. L. Clark, Mem. Mus. Comp. Zool., Vol. 46, No. 2, p. 251, 1917. “Type, Lovenia hystrix Agassiz and Desor, 1847
=Spatangus elongatus Gray, 1845, Eyre, Voy. 1, p. 436.”—Lambert and Thiéry, Essai Nomencl. Raison. Echinid., Fasc.
6 & 7, p. 466, 1924. “Type: L. elongata Gray (Spatangus) vivant de l’Océan Indien, dont L. hystrix Desor est un simple
synonyme.”—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 135, 1938. “Type of the
genus (by monotypy): Lovenia “Hystrix Desor’ . . . =Spatangus elongatus Gray.” —Mortensen, Monogr. Echin. V.2.
Spatangoida.II, p. 89, December 20, 1951. “Genotype: Lovenia elongata (Gray).”

Type spectes (by monotypy): “Hystrix Desor. —Descript. Egypt. Zool., Pl. 7, fig. 4,” in

L. Agassiz and Desor, Ann. Sci. Nat. (Zool.), Ser. 3, Vol. 8, p. 11, pl. 16 (Vol. 6), fig. 16, 1847.

“Mer Rouge (Botta). —Mus. Paris.” [== Spatangus elongatus Gray in E. J. Eyre, Jour. Centr.

Austral., Vol. 1, p. 436, pl. 6, fig. 2, 1845. Australia. Illustrated by A. Agassiz, Illustr. Cat. Mus.

Comp. Zool., No. 7 (Mem. Mus. Comp. Zool., Vol. 3), Pt. 1, p. 139, 1872; Pt. 3, p. 575, pl. 19c,

figs. 1-4; pl. 25, fig. 31; pl. 26, figs. 35, 36; pl. 37, figs. 17, 18; pl. 38, figs. 27, 28, 1873. “Red Sea;

Australia; Philippine Islands.” Also Zanzibar. —Mortensen, 1951, p. 97, figs. 48a, 49, 50, 51, 52a;

(120) Spatangus corsicus Desor in L. Agassiz and Desor, Ann. Sci. Nat. (Zool.), Ser. 3, Vol. 8, p. 7, July, 1847. “Tert.
de Balestro (Corse), Saint-Paul-Trois-Chateaux (Dréme).” Figured by Loriol, Direction des Travaux Géologiques du Portugal.
Description des Echinodermes Tertiaires du Portugal, pp. 47-48, pl. 13, figs. 3, 3a, 3b, 1896. “Bassin du Tage.” Also “Santa
Manza, Balistro, (Corse). (Helvétien).—Sardaigne. (Langhien ).”

(121) Spatangus californicus H. L. Clark, Mem. Mus. Comp. Zool., Vol. 46, No. 2, p. 235, pl. 146, fig. 20; pl. 149, fig. 4;
pl. 156, figs. 1-3; pl. 157, fig. 10, March, 1917. “Off southern California.” “68 fms.” Bathymetric range, 45-73 fathoms. Extremes
of temperature, 56.5°-42.4°F.—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 132, pl. 10,
fig. 5; pl. 30, fig. 5, 1938. Off southern California to Cedros Island, Lower California. It also occurs at least as far north as
Cordell Bank in central California. See also Mortensen (1951, p. 16, pl. 2, figs. 1, 2).

This species was cited erroneously as Spatangus pacificus by Israelsky (1923, p. 383).

(122) Prospatangus n. sp., Szérényi, Geol. Hungarica, Ser. Palaeo., Fasc. 23, p. 91, pl. 7, fig. 6, 1953. “Grabnik,” western
Ukraine. Miocene.

130 San Dreco Socrery oF Naturat History [ Memorrs

pl. 7, figs. 1-10; pl. 8, fig. 1; pl. 12, fig. 5; pl. 47, figs. 10-23. Indo-Pacific. See also H. L. Clark,
Carnegie Inst. Washington, Publ. 566, p. 381, 1946. North Australia, South Africa, and Aden to
Misaki, Japan. }

RANGE: Miocene to Recent. Cosmopolitan. Bathymetric range, in west American waters (L.
cordiformis), usually from ebb tide to 137 meters (75 fathoms); one species in the Indo-Pacific
(L. gregalis Alcock) occurs to a depth of 930 meters (509 fathoms) according to Mortensen (1951,
p. 123).

Description: An internal fasciole present but no peripetalous; large, deeply sunken primary
tubercles present in interambulacra on both upper and lower surfaces; sternum with tubercles confined

to posterior part; petals I and V well formed. (H. L. Clark, 1925. )

Remarks: Pseudolovenia A. Agassiz and H. L. Clark’) is believed to be closely related to
Lovenia, but it differs in that petals I and V are not at all petaloid and that the anterior petals are
longer and narrower.

Only two species of Lovenia have been described from western North America: L. hemphilli
Israelsky from Pliocene strata at San Diego, and L. cordiformis A. Agassiz, a Recent species described
from Guaymas and the Gulf of California, ranging from Point Conception, California, to Panama, from
the intertidal zone to a depth of 137 meters (75 fathoms). Mortensen recognized nine species and one
variety of Lovenia as now living. The genus has not been reported from the Atlantic Ocean, but it
is represented by fossil forms in late Tertiary strata in that region.

Lovenia hemphilli Israelsky
Plate 24, Figures 1-3, 18

Lovenia hemphilli Israelsky, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 11, p. 384, pl. 74, figs. la-lc, 2, November
7, 1923. “Pacific Beach, San Diego Co., California,” Pliocene—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math.
Phys. Sci., Vol. 2, p. 137, pl. 13, figs. 3, 4, 1938. “Pacific Beach, San Diego”; “near Market Street and Euclid Avenue,
San Diego.”—Hertlein and Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2, p. 57, 1944. “Pacific Beach.”—Durham,
Geol. Soc. Amer., Mem. 43, Pt. 2, p. 51, pl. 44, figs. 2, 6 (Monserrate Island, Pliocene), 3, 4 (San Diego Pliocene),
1950. “San Diego Pliocene.”—Hertlein and Grant, Calif. State Div. Mines, Bull. 170, chapter 2, p. 60, 1954 (1955).

“San Diego formation.”
TyPE SPECIMEN: “Cotypes” [Syntypes} Nos. 918 and 919, Type Collection, Department of
Geology, California Academy of Sciences.

TYPE LOCALITY: “Pacific Beach San Die fo) Co: California.” “Pliocene San Diego formation.”
5) g ? ? g
In “Micaceous sandstone.”

Rance: Middle Pliocene in southern California and at Monserrate Island, Gulf of California.

OccuRRENCE IN THE SAN DrEGO FORMATION: CALIFORNIA ACADEMY OF SCIENCES: Loc. 547, Pacific Beach (Israelsky;
Grant and Hertlein); Loc. 1399, road cut 0.1 mile east of Euclid Avenue on Market Street; Loc. 1413, lower beds in Pliocene sec-
tion at Pacific Beach; Loc. 1414, middle beds in Pliocene section at Pacific Beach. Los ANGELES County Museum: (?)Loc.
107, 100-foot bluff, with scattered fossiliferous concretions in clay quarry at end of Arroyo Drive, San Diego; Loc. 122, 20 to
30 feet below end of Loring Street, Pacific Beach.

ORIGINAL DESCRIPTION: Outline of test from above slightly cordiform, notched anteriorly,
narrowed, and shallowly truncated posteriorly, greatest width slightly anterior to the apical system;
greatest height posterior to apical system about two-thirds of distance from that system to the posterior
truncation in the odd interambulacral area which is somewhat ridged. Apical system forward of center
of test. Anterior odd ambulacrum in groove which reaches from the ambitus nearly to the apex.
Antero-lateral petals sub-triangular, pointed anteriorly, slightly depressed, aborted by internal fasciole
near the apical system, with anterior pore rows approximating a straight line transverse to the major
diameter of the test; petals reach two-thirds of distance to ambitus. Postero-lateral petals nearly twice
as long as the anterior, more lanceolate in outline, posterior pore rows forming an angle of about 80°
one with the other. Pores in petals large, zygose. Primary tubercles present in all interambulacra
excepting the odd posterior, the number varying with the individual (age factor) ; deeply scrobiculate,
reflected internally by overlapping rings; primaries not found on ambital area. Miliaries found over

(123) Pseudolovenia A. Agassiz and H. L. Clark, Bull. Mus. Comp. Zool., Vol. 50, No. 8, p. 255, March, 1907. Type (by
monotypy): Pseudolovenia hirsuta A. Agassiz and H. L. Clark. Several localities off the Hawaiian Islands in 192-692 fathoms.
Figured by H. L. Clark, Mem. Mus. Comp. Zool., Vol. 46, No. 2, pp. 258-261, pl. 146, figs. 32, 33; pl. 160, figs. 8-12, 1917.

Hawaiian Islands and Japan.

Votume II] MarINE PLIOCENE OF SAN D1EGO, CALIFORNIA 131

entire test. Peristome anterior to center of actinal side. Periproct posterior, lying in upper portion of
deeply sunken depression which obliquely truncates the test at rear. (Israelsky.

Measurements { Israelsky }: Cotype No. 918, CAS Cotype No. 919, CAS
WEES 000 0 oer renee eee 79.5 mm.

Remarks: Eight specimens of this species in various states of preservation were collected by
George P. Kanakoff and J. F. Arndt at Loc. 122 (LAM), Pacific Beach. These vary in length from
74.6 mm. to 82 mm. and in width from 56 mm. to 62 mm. In addition to these and the syntypes,
we have studied a few other specimens, mostly incomplete ones, from Pacific Beach and from other
localities. The exposed portions of all the specimens available to us from the San Diego area reveal
the characteristic features of the syntypes.

Lovenia hemphilli differs from the Recent west American L. cordiformis A. Agassiz in that
the test is lower in proportion to the length and that the posterior truncation is sloping rather than
nearly vertical. Lovenia cordiformis ranges''*”) from Point Concepcion, California, to Panama and the
Galapagos Islands, from shore to a depth of 137 meters (75 fathoms). Mortensen (1951, p. 108)
thought that either L. hemphilli or L. dumblei Dickerson and Kew''*®) might be the ancestor of
L. cordiformis.

Israelsky pointed out the resemblance of L. hemphilli to L. elongata Gray (= L. hystrix, type
species of Lovenia), but it differs in the character of the petals. He also called attention to the striking
resemblance of L. hemphilli to Sarsella duncani Gregory''’’’, described from Oligocene Globigerina
limestone of Malta.

(124)

L. hemphilli resembles members of the L. elongata group, which includes L. camarota H. L.
Clark'?®), L. elongata Gray, L. cordiformis A. Agassiz, and L. hawaiiensis Mortensen. Lovenia similis
H. L. Clark’, from Miocene strata in Fiji, may be another member of this group; but Mortensen
expressed doubt that it is referable to the genus Lovenia. He suggested that it might belong to the
genus Breynia Desor.

Family SCHIZASTERIDAE Lambert

The main character of this family is the presence (excepting Amphipneustes) of both a peripetalous
and a latero-anal fasciole. (Mortensen, 1951.) Late Cretaceous to Recent.

Genus BRISASTER Gray

Brisaster Gray, Cat. Rec. Echin. Brit. Mus., p. 61, 1855. Species cited: Schizaster fragilis Diiben and Koren (Brissus fragilis Diben
and Koren), “Hab. Shores of Finmark”; Schizaster gibberulus Agassiz and Desor, “Hab. Red Sea”; Schizaster cubensis
d’Orbigny, “Hab. Cuba, D’Orbigny”.—H. L. Clark, Cat. Rec. Sea-Urchins Brit. Mus., p. 206, 1925. “Type, Brissus
fragilis Duben and Koren”.—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 122, April 19,
1938. Type as in preceding reference——Mortensen, Monogr. Echin., V.2. Spatangoida. II, p. 280, December 20, 1951.
“Genotype: Brisaster fragilis (Diiben & Koren).”

Lymanaster Lambert in Castex and Lambert, Actes Soc. Linn. Bordeaux, Vol. 71, p. 52, 1920. Type: Brisaster townsendi A.
Agassiz.

(124) Lovenia cordiformis A. Agassiz, Bull. Mus. Comp. Zool., Vol. 3, No. 4, p. 57, 1872. “Mus. Comp. Zool. Guayamas;
Smith. Coll. Gulf of California.” Footnote states “Liitken MS. in litt.’—Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math.
Phys. Sci., Vol. 2, p. 136, pl. 11, figs. 2, 3; pl. 13, figs. 1, 2, 1938. Pleistocene and Recent. {Mortensen (1951, V.2, p. 107)
considered Liitken to be the author of this species and Guayaquil, Ecuador, to be the type locality. }

(125) Lovenia cordiformis was recorded from the Hawaiian Islands by Ziesenhenne (1937, p. 236) and by H. L. Clark.
Mortensen doubted the Hawaiian occurrences, believing that those records may be referable to L. hawaiiensis Mortensen (see
Mortensen 1951, p. 107, pl. 13, figs. 24-30; pl. 48, figs. 2, 6, 7).

(126) Lovenia dumblei Dickerson and Kew, Proc. Calif. Acad. Sci., Ser. 4, Vol. 7, p. 136, pl. 17, figs. 2a-2c, July 30, 1917.
Type locality, “Nuevo Rancho, 35 kilometers northwest of Tuxpan, near Cerro Azul,” Mexico. “Upper Oligocene or Miocene.”

(127) Sarsella duncani Gregory, Trans. Roy. Soc. Edinburgh, Vol. 36, Pt. 3, p. 624, 1890-1891 (May 10, 1892). Ref. to
Spatangus ocellatus Defrance of T. Wright (non Defrance, 1827), Quart. Jour. Geol. Soc. London, Vol. 20, pp. 487-488, pl. 21,
figs. la, 1b, 1864.

(128) Lovenia camarota H. L. Clark, Mem. Mus. Comp. Zool., Vol. 46, No. 2, p. 253, pl. 161, figs. 1-4, March, 1917

. . “west of Torres Strait, 28 fms., mud.”

(129) Loyvenia similis H. L. Clark, Bernice P. Bishop Mus., Bull. 181, p. 327, pl. 43, fig. G, January, 1945. “Oneata,’” Island

of Lau group, Fiji, probably late Miocene.

132 San Dieco Society oF NaturaL History [Memorrs

Type spectes (designated by Lambert, Mém. Soc. Geol. France, Paléo., Tom. 14, Fasc. 2-3
(Mém. No. 24) p. 112, 1906): Brisaster fragilis Duben and Koren [= Brissus fragilis Diben and
Koren, Kgl. Vetensk. Akad. Handl., p. 280, Tab. 10, figs. 47-49, 1844. Illustrated by Mortensen,
1951, pl. 23, figs. 1, 16-19. (Synon. pp. 283-284). Barents Sea, Murman coast and North Atlantic
to Bergen, Norway, and Iceland and from Lat. 66°N. to Florida in west Atlantic, in 40 to 1300 meters. |

RANGE: Eocene to Recent (Lambert and Thiéry, 1925). [According to Mortensen, many of
the species referred to Brisaster by Lambert and Thiéry are not referable to that genus.} Recent in
North Atlantic, South Atlantic, eastern Pacific, and Japan, in 35 to 1900 meters (19 to 1039 fathoms).

Description: Test low, apex posterior; genital pores 3; posterior petals relatively short; petals
II and IV at first little divergent, then becoming more so, and at tip markedly curved outward.
(H. L. Clark, 1925.)

Remarks: Brisaster is represented in the Oligocene of Oregon by B. maximus H. L. Clark, and
in the Pliocene of California by Brisaster cf. B. townsendi A. Agassiz, by a subspecies described here as
B. townsendi woynari, and perhaps by “Schizaster (?)” stalderi Weaver.

Seven species of this genus are recorded by Mortensen as occurring in the seas at the present
time.

The test of Faorina Gray, which also possesses 3 genital pores, has the apical system nearly central,
and the peripetalous fasciole is double anteriorly.

Brisaster townsendi woynari Hertlein and Grant, new subspecies

Plate 25, Figure 5; Plate 26, Figures 1-3

Description: Test is similar to that of Brisaster townsendi A. Agassiz in general features. The
apex is about two-fifths of the distance from the posterior end, and the petals of the bivium, angle about
100°, are a little more than one-half the length of petals II and IV. The subspecies differs from typical
B. townsendi in the greater size and more nearly quadrate outline of the test and in the more nearly
central position of the apical system. Spines on the plastron are about 8 mm. in length. The test may
be slightly crushed as a result of the compaction of the sediment, but the specimens available are
comparatively uniform in outline. Dimensions are as follows: holotype, length 91.5 mm., width 90 mm.,
height 34.5 mm.; paratype, length 90 mm., width 92 mm., height 35.5 mm.; paratype, length 92 mm.,
width 91.8 mm., height 35.5 mm.

Two large specimens, slightly crushed and partly covered with concretionary material, have the
following measurements: the larger one, length 97 mm., width 101 mm., height 33 mm.; the other
one, length 94 mm., width 91 mm., height 32.5 mm.

Type SPECIMENS: Holotype and Paratypes, Invertebrate Paleontology Collection, Los Angeles
County Museum.

Type Locatity: Loc. 107 (LAM), 100-foot bluff with scattered fossiliferous concretions in clay
quarry at end of Arroyo Drive, San Diego; C. W. Woynar, coll.; San Diego formation, Pliocene.

RANGE: Known only from the type locality.

Remarks: Portions of the specimens of this new subspecies are covered with a very hard matrix
of sandstone, but most of the shell characters are revealed. The angle of the bivium is about 100°,
whereas in the Recent Brisaster townsendi A. Agassiz”) the angle is about 105 to 110°. This apparent
difference may not be significant, for Mortensen has pointed out that anomalies in the form of the
bivium occur in Recent specimens of B. townsendi. However, taken as a whole, the characters enumerated
in the description of the present fossil form appear to differ from those of the Recent species sufficiently
to justify its status as a distinct subspecies.

(130) Schizaster townsendi A. Agassiz, Bull. Mus. Comp. Zool., Vol. 32, No. 5, p. 82, June, 1898. Gulf of Panama, 146-
995 fathoms and 50 miles south of Guaymas, Mexico, in 628 fathoms.

Brisaster townsendi A. Agassiz, Grant and Hertlein, Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 123,
pl. 1, fig. 6; pl. 14, figs. 1-3, 1938. Earlier records cited; also various records from western North America. Pliocene to Recent.
—H. L. Clark, Allan Hancock Pac. Exped., Vol. 8, No. 5, p. 340, pl. 64, fig. 64, 1948. Southeastern Alaska to the Galapagos
Islands in 20 to 995 fathoms.—Mortensen, Monogr. Echin., V.2. Spatangoida. II, p. 288, pl. 24, figs. 1, 2, 9-19; pl. 53, figs.
21-27, 1951. Southeastern Alaska to Panama, 35-1900 meters.

Votume II] Marine PLIOCENE OF SAN Deco, CALIFORNIA 133

An imperfectly preserved specimen of a Brisaster approximately 55.5 mm. long and 52.6 mm. wide,
in the collections of the San Diego Society of Natural History, was collected by W. E. Pennington
at Pacific Beach. The anterior portion of the aboral surface of the specimen, bearing a peripetalous
fasciole, agrees with that of the present subspecies and likewise is similar to that of Recent specimens
of Brisaster townsendi of comparable size except that ambulacrum III is narrower. This latter feature
might be due to compaction of the sediment.

A fragment of a sea-biscuit, 46 mm. long, from Loc. 122 (LAM), Pacific Beach, appears to be
referable to the genus Brisaster. It may, perhaps, represent a young specimen of the new subspecies
described above.

The largest specimen of Recent Brisaster townsendi A. Agassiz that we have seen is one measuring
70 mm. in length from Loc. 24834 (CAS), off Bainbridge Island, Washington, in 219 meters (120
fathoms). Mortensen (1951, p. 289) mentioned a specimen 77 mm. in length. According to the
same author, the type species of the genus, B. fragilis, attains a length of 90 mm. A series of specimens
of B. townsendi shows considerable variation in the degree of flatness of the abactinal surface.

The present authors (1938, p. 123) recorded a specimen under the name of “Brisaster cf. townsendi”
from strata of Pliocene age from a well in Orange County, California. Mortensen (1951, p. 282)
suggested that the species described as Schizaster (?) stalderi by Weaver“'*’) from Pliocene beds in
northern California is probably referable to the genus Brisaster. The only other species of this genus
recorded as a fossil from western North America is Brisaster maximus H. L. Clark‘’?”) (length about
84 mm., width approximately 76 mm.) from beds of Oligocene age in western Oregon.

Brisaster townsendi ranges from the Bering Sea to the Gulf of California and south to Panama,
in 20 to 1900 meters (11 to 1039 fathoms). It is abundant off the coast of California in 91 to 146
meters (50 to 80 fathoms).

This new subspecies is named for Mr. William C. Woynar, San Diego, California, who collected
the type specimens.

(131) Schizaster (?) stalderi Weaver, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 5, No. 17, p. 274, pl. 21, fig. 3, December
28, 1908. “Humboldt County, California, in beds presumed to represent the Wild Cat series of Lawson.”—Grant and Hertlein,
Publ. Univ. Calif. Los Angeles Math. Phys. Sci., Vol. 2, p. 121, pl. 25, fig. 6, 1938. Earlier records cited. Pliocene.

(132) Brisaster maximus H. L. Clark, Trans. San Diego Soc. Nat. Hist., Vol. 8, No. 28, p. 368, pl. 24, fig. 9, December
15, 1937.—Weaver, Univ. Washington Publ. Geol., Vol. 5, p. 11, pl. 4, fig. 5, issued December 31, 1943.

PLATES 19 TO 26

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EXPLANATION OF PLATE 19

Astrangia cf. A. insignifica Nomland. Hypotype (Los Angeles County Museum), from Loc. 305 (LAM), 2400 feet
east and 1350 feet south of northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian, southwestern
San Diego County, California (see U.S. Geol. Surv. topographic map, San Ysidro quadrangle, ed. 1943). Diameter
of calice 4.3 mm. P. 79

Astrangia cf. A. insignifica Nomland. Hypotype (Los Angeles County Museum), from same locality as specimen shown
in fig. 1. Diameter of calice 3.2 mm. P. 79

Astrangia cf. A. insignifica Nomland. Side view of specimen shown in fig. 2.
Astrangia cf. A. insignifica Nomland. Base of specimen shown in figs. 2 and 3.

Dendrophyllia cf. D. oldroydi Faustino. Hypotype (Los Angeles County Museum), from same locality as specimen
shown in fig. 1, showing interior of calice. Length of specimen 19 mm. See also figs. 6 and 15 . P. 82

Dendrophyllia cf. D. oldroydi Faustino. Hypotype (Los Angeles County Museum); same specimen as shown in figs.
5 and 15, showing branching character. P. 82

Astrangia cf. A. insignifica Nomland. Base of specimen shown in fig. 1.

Paracyathus stearnsii Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.
Side view. Height 16.2 mm. P. 80

Paracyathus stearnsii Verrill. Corallum of specimen shown in fig. 8. Greater diameter of calice 15 mm.; lesser diameter

11 mm. P. 80

. Paracyathus stearnsii Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in

fig. 1. Height of specimen 9 mm.; greater diameter of calice 9 mm. P. 80

. Paracyathus stearnsii Verrill. Same specimen shown in fig. 10, showing character of budding.
. Paracyathus stearnsii Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig.

1. Exterior of portion of corallum. Height of specimen 7.8 mm. P. 80

. Paracyathus stearnsii Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.

Greater diameter of calice approximately 11.3 mm.; lesser diameter 9.4 mm. P. 80

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1,

showing one individual attached to another. Height of specimen 10 mm. P. 84

. Dendrophyllia cf. D. oldroydi Faustino. Hypotype (Los Angeles County Museum); same specimen shown in figs. 5 and

6. Calice diameter 9.5 mm. P. 82

. Terebratalia occidentalis Dall. Hypotype (California Academy of Sciences), from Loc. 1419 (CAS), northeast corner

of India and Thorn streets, San Diego, California. View of exterior of pedicle valve. Length 14.9 mm.; width 19.3 mm.
P. 94

. Glottidia albida Hinds. Hypotype (University of California at Los Angeles), from Loc. L-309 (UCLA), southeast

corner of India and Upas streets, San Diego, California. Length 12.5 mm.; width 8 mm. Interior of apical portion of
pedicle valve, showing diverging laminae. P. 89

. Glottidia albida Hinds. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.

Length 12 mm.; width 5.5 mm. Exterior of dorsal valve. P. 89

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.

Height 21 mm.; maximum diameter 7 mm. P. 84

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.

Height 13.8 mm.; maximum diameter 7.3 mm. P. 84

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.

Height 15 mm.; maximum diameter approximately 7.5 mm. P. 84

_ Terebratalia occidentalis Dall. Hypotype (California Academy of Sciences), from Loc. 28159 (CAS), Pacific Beach,

San Diego, California. Length 16 mm.; width, incomplete, 20.4 mm. Exterior of dorsal valve. P. 94

. Glottidia albida Hinds. Hypotype (California Academy of Sciences), from Loc. 1401 (CAS), south slope of Soledad

Mountain, San Diego, California. Length 9.3 mm.; width 5 mm, Exterior of dorsal valve. P. 89

. Glottidia albida Hinds. Hypotype (Los Angeles County Museum), 50 feet northeast of Loc. 107 (LAM), clay quarry

at end of Arroyo Drive, San Diego, California. Length 19.9 mm.; width (one valve) approximately 7.8 mm. Exterior
of dorsal valve. P. 89

- Glottidia albida Hinds. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 24.

Length 21 mm.; width 10 mm. Exterior of pedicle valve. P. 89

. Terebratalia hemphilli Dall. Hypotype (Los Angeles County Museum), from Loc. 122 (LAM), Pacific Beach, San

Diego, California. Length 38.9 mm.; width (incomplete) 38 mm. Exterior of pedicle valve. P. 93

. Terebratalia hemphilli Dall. Hypotype (California Academy of Sciences), from Loc. 547 (CAS), Pacific Beach, San

Diego, California. Length 40.6 mm.; width (incomplete) 38 mm. Exterior of brachial valve. P. 93

. Strongylocentrotus franciscanus A. Agassiz. Hypotype (California Academy of Sciences), from Loc. 12163 (CAS),

Pacific Beach, San Diego, California. Portion of a small test. Diameter 21.5 mm. P. 111

. Strongylocentrotus purpuratus Stimpson. Hypotype (Los Angeles County Museum), from Loc. 153 (LAM), Pacific

Beach, San Diego, California. Portion of somewhat crushed test. Diameter 79.6 mm. P. 112

- Terebratalia arnoldi Hertlein and Grant. Hypotype (California Academy of Sciences), from Loc. 1399 (CAS), Pacific

Beach, San Diego, California. Length 41 mm.; width 39.3 mm. Exterior of pedicle valve. P. 92

. Terebratalia occidentalis Dall. Hypotype (No. 7324, California Academy of Sciences), from Loc. 12007 (CAS), Pacific

Beach, San Diego, California. Length 21 mm.; width 27.2 mm.; convexity of brachial valve 5.7mm. Exterior of brachial
valve. P. 94

PLaTE 19

MarINnE PLIOCENE OF SAN Dieco, CALIFORNIA

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EXPLANATION OF PLATE 20

Laqueus californianus Koch. Hypotype (Los Angeles County Museum), from Loc. 107 (LAM), clay quarry at end
of Arroyo Drive, San Diego, California. Length 38 mm.; width 33.3 mm.; convexity (both valves together) 18 mm.
Pedicle valve. P. 96

Laqueus californianus Koch. Dorsal view of specimen shown in fig. 1.
Laqueus californianus Koch. Side view of specimen shown in figs. 1 and 2.

Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Paratype (Los Angeles County Museum), from
Loc. 122 (LAM), 20 to 30 feet below end of Loring Street, Pacific Beach, San Diego, California. Length 36.4 mm.;
width 28 mm.; convexity (both valves together) 22.5 mm. Pedicle valve. P. 97

Laqueus californianus Koch. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 1.
Length 38.2 mm.; width 29 mm.; convexity (both valves together) 18.2 mm. Dorsal view. P. 96

Laqueus californianus Koch. Dorsal view of specimen shown in fig. 5.
Laqueus californianus Koch. Side view of specimen shown in figs. 5 and 6.
Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Dorsal view of specimen shown in fig. 4.

Laqueus vancouyeriensis diegensis Hertlein and Grant new subspecies, Holotype (No. 7355, California Academy of
Sciences), from Loc. 12005 (CAS), Pacific Beach, San Diego, California. Length 34.5 mm.; width 29.5 mm.; convexity
(both valves together) 21.6 mm. Pedicle valve. P. 97

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Holotype. Dorsal view of specimen shown in fig. 9.

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Holotype. Side view of specimen shown in figs. 9

and 10.

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Side view of specimen shown in figs. 4 and 8.

. Laqueus vancouveriensis diegensis Hertlein and Grant, new,-subspecies. Paratype (No. 7354, California Academy of

Sciences), from Loc. 537 (CAS), Pacific Beach, San Diego, California. Length 33.8 mm.; width 31 mm.; convexity
(both valves together) 20.5 mm. Pedicle valve. P. 97

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Dorsal view of specimen shown in fig. 13.
. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Side view of specimen shown in figs. 13 and 14.

. Laqueus vancouyeriensis diegensis Hertlein and Grant, new subspecies. Paratype (San Diego Society of Natural History),

from Loc. 726 (SD), Pacific Beach, San Diego, California. Length 30.6 mm.; width 24 mm.; convexity (both valves
together) 20.3 mm. Pedicle valve. P. 97

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Dorsal view of specimen shown in fig. 16.

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Paratype (Cat. No. 2420, University of California

at Los Angeles), bluffs along Pacific Beach, about 1/, mile southeast of False Point, La Jolla quadrangle, San Diego,
California. Length 35.9 mm.; width 32.5 mm.; convexity (pedicle valve) 11.2 mm. Exterior of pedicle valve. P. 97

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Interior of valve shown in fig. 18.

. Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Paratype (University of California at Los Angeles),

from same locality as specimen shown in figs. 18 and 19. Length 35 mm.; width 33 mm.; convexity (both valves together )
16.4 mm. Specimen slightly crushed. Pedicle valve. P. 97

Laqueus vancouveriensis diegensis Hertlein and Grant, new subspecies. Dorsal view of specimen shown in fig. 20.

MarInE PLIOCENE OF SAN DieGo, CALIFORNIA Piate 20

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EXPLANATION OF PLATE 21

Dendraster ashleyi Arnold. Hypotype (No. 6325, University of California at Los Angeles), from Quayle’s Loc. 8, Las
Chollas Valley, San Diego, California. Length 66 mm.; width 75 mm.; height approximately 11 mm. Aboral surface.
Pgll7

Dendraster ashleyi Arnold. Hypotype (Los Angeles County Museum), from Loc. 306 (LAM), east side of Euclid
Avenue between Federal Boulevard and intersection of Euclid and Home avenues, San Diego, California. Length 52.3
mm.; width 57 mm.; height approximately 8.5 mm. Oral surface. P. 117

Dendraster ashleyi Arnold. Hypotype Cat. No. 3374, (University of California at Los Angeles) , from Loc. 296 (UCLA),
street cut on northwest side of Fairmount extension, 0.4 mile north of intersection with Broadway, on west side of Las
Chollas Valley, San Diego, California. Length 58.9 mm.; width 66.7 mm.; height approximately 9.2 mm. Aboral surface.
P. 117

Dendraster ashleyi ynezensis Kew. Hypotype (Los Angeles County Museum), from Loc. 107 (LAM), clay quarry at end
of Arroyo Drive, San Diego, California. Length 77.6 mm.; width 86 mm.; height approximately 10.5 mm. Oral surface,
with spines. G. P. Kanakoff, collector. P. 118

Dendraster ashleyi ynezensis Kew. Hypotype (Los Angeles County Museum), from Loc. 127 (LAM), at Encanto,
Wabash Freeway, Market Street continuation, 1/4 mile south of Euclid Avenue, San Diego, California. Length 76 mm.;
width 85.3 mm.; height approximately 9.0 mm. Aboral surface. P. 118

Dendraster ashleyi Arnold. Hypotype (Los Angeles Gounty -Museum), from 2400 block, east side of Euclid Avenue,
San Diego, California. Length 58.5 mm.; width 66.2 mm.; height 9.0 mm. P. 117

Marine PLIOCENE OF SAN D1eEGo, CALIFORNIA

PLATE

21

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EXPLANATION OF PLATE 22

Dendraster ashleyi Arnold. Hypotype (Los Angeles County Museum), from Loc. 306 (LAM), on east side of Euclid
Avenue, between Federal Boulevard and intersection of Euclid and Home avenues, San Diego, California. Length 58.7
mm.; width 66.8 mm.; height approximately 6.3 mm. Aboral surface. P. 117

Dendraster ashleyi ynezensis Kew. Hypotype (Los Angeles County Museum), from Loc. 294 (LAM), back of house
No. 3550 on Dove Street, San Diego, California. Length 20.5 mm.; width 20.6 mm.; height approximately 2.6 mm.
Aboral surface of small specimen. P. 118

Dendraster ashleyi Arnold. Hypotype (Cat. No. 3374, University of California at Los Angeles), from Loc. 296 (UCLA),
street cut on northwest side of Fairmount extension, 0.4 mile north of intersection with Broadway, on west side of Las
Chollas Valley, San Diego, California. Length 59 mm.; width 66.6 mm.; height 8.5 mm. Aboral surface. P. 117

Dendraster ashleyi ynezensis Kew. Hypotype (University of California at Los Angeles), from same locality as specimen
shown in fig. 3. Length 61.4 mm.; width 67 mm.; height 9.8 mm. Oral surface of specimen intermediate between
Dendraster ashleyi and D. a. ynezensts. P. 118

Dendraster gibbsti humilis Kew. Hypotype (California Academy of Sciences), from Loc. 12164 (CAS), Pacific Beach,
San Diego, California. Length 44.2 mm.; width 48.2 mm.; height 9.5 mm. P. 120

Dendraster ashleyi ynezensis Kew. Hypotype (University of California at Los Angeles), from same locality as specimen
shown in fig. 3. Length 28.6 mm.; width 29.9 mm.; height approximately 3 mm. Aboral surface of small specimen.
P. 118

Dendraster casseli Grant and Hertlein. Hypotype (Los Angeles County Museum), from Loc. 107 (LAM), clay quarry
at end of Arroyo Drive, San Diego, California. Length 56.9 mm.; width 60.8 mm.; height approximately 6.3 mm.
Aboral surface. P. 120

Dendraster ashleyi ynezensis Kew. Hypotype (No. 4018, University of California at Los Angeles), from Las Chollas
Valley, above Market Street bridge, San Diego, California; collected by E. H. Quayle. Length 88.3 mm.; width 98 mm.;
height approximately 9.2 mm. Aboral surface.

This form is larger and rounder than typical D. ashleyi, and the angle of the bivium is smaller. P. 118

Dendraster gibbsii humilis Kew. Oral surface of specimen shown in fig. 5.

PLaTE 22

Marine PLiIoceNE OF SAN D1kEGo, CALIFORNIA

EXPLANATION OF PLATE 23

Fic. 1. Merriamaster pacificus Kew. Holotype (No. 448, California Academy of Sciences), from Loc. 537 (CAS), Pacific
Beach, San Diego, California. Length 36 mm.; width 35 mm.; height 8.3 mm. Aboral surface. P. 124

Fic. 2. Merriamaster pacificus Kew. Hypotype (Los Angeles County Museum), from Loc. 308 (LAM), 0.2 mile north of
intersection of Harbor Boulevard and Tourmaline Street, Pacific Beach, San Diego, California. Length 28.5 mm.; width
27 mm.; height 7.3 mm. Aboral surface. P. 124

Fic. 3. Merriamaster pacificus Kew. Oral surface of specimen shown in fig. 2.

Fic. 4. Merriamaster pacificus Kew. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 2.
Length 23 mm.; width 21 mm.; height 4.8 mm. Aboral surface of small specimen. P. 124

Fic. 5. Merriamaster pacificus Kew. Oral surface of specimen shown in fig. 1.

Fic. 6. Merriamaster pacificus Kew. Hypotype (Los Angeles County Museum), from Loc. 122 (LAM), 20 to 30 feet below
end of Loring Street, Pacific Beach, San Diego, California. Length 28.3 mm.; width 26.7 mm.; height 6.4 mm. Oral
surface. P. 124

Fic. 7. Encope tenuis Kew. Hypotype (Los Angeles County Museum), from Loc. 107 (LAM), clay quarry at end of Arroyo
Drive, San Diego, California; G. P. Kanakoff, collector. Length 104 mm.; transverse diameter (incomplete) 97 mm.;
height 12 mm. Aboral surface. P. 126

Fic. 8. Astropecten armatus Gray. Hypotype (University of California at Los Angeles), from corner of Market Street and
Euclid Avenue, San Diego, California. Length 13.8 mm.; maximum width 12 mm. Aboral surface of fragment of ray.
P. 100

Fic. 9. Astropecten armatus Gray. Oral surface of specimen shown in fig. 8.

Fic. 10. Merriamaster cf. M. israelskyi E. K. Jordan and Hertlein. Hypotype (San Diego Society of Natural History), from
Balboa Park, San Diego, California. Length 43.4 mm.; width 43.4 mm, Oral surface. P. 122

Fic. 11. Merriamaster pacificus Kew. Side view of specimen shown in figs. 2 and 3.

Fic. 12. Merriamaster cf. M. israelskyi E. K. Jordan and Hertlein. Hypotype (Los Angeles County Museum), from Loc. 124
(LAM), 15 feet below floor of Snyder Continuation Schéol, San Diego, California. Length (incomplete) 71.8 mm.;
width (incomplete) 41 mm. Oral surface of portion of large specimen. P. 122

Fic. 13.* Encope tenuis Kew. Oral surface of specimen shown in fig. 7.

Fic. 14. Merriamaster cf. M. israelskyi E. K. Jordan and Hertlein. Hypotype (Los Angeles County Museum), from same
locality as specimen shown in fig. 12. Length 32.5 mm.; width (incomplete) 29.5 mm. Aboral surface of portion of
specimen. P. 122

*Two details in figures 7 and 13 are inexact because of tooling out by the engraver. The small fissure at the central top
margin, an imperfection in the fossil, is actually 4mm. long; and the closed posterior lunule is oval in shape and 4 by 3 mm.

PLATE 23

Marine PLiIocENE OF SAN D1EGO, CALIFORNIA

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EXPLANATION OF PLATE 24

Lovenia hemphilli Israelsky. Syntype (No. 918, California Academy of Sciences), from Loc. 12165 (CAS), Pacific
Beach, San Diego, California. Length 75 mm.; width 63.1 mm.; height 19.9 mm. Aboral surface. P. 130

Lovenia hemphilli Israelsky. Oral surface of specimen shown in fig. 1.
Lovenia hemphilli Israelsky. Side view of specimen shown in figs. 1 and 2. Anterior end toward the right.

Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from Loc. 305 (LAM), 2400 feet east and
1350 feet south of northwest corner of Sec. 8, T.19S., R.2W., San Bernardino Base and Meridian, southwestern San
Diego County, California (see U.S. Geol. Surv. topographic map, San Ysidro quadrangle, ed. 1943). Height 16.6 mm.;
maximum diameter of corallum 6.4 mm. P. 84

Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 4.
Height 15 mm.; maximum diameter of corallum 7 mm. P. 84

Hesperocidaris perplexa H. L. Clark. Hypotype (California Academy of Sciences), from Loc. 1183 (CAS), Eagle
Street just north of Quince Street and just east of Reynard Way, San Diego, California. Length 18.3 mm.; maximum
diameter 2.9 mm. Portion of spine flattened at distal end, as is characteristic of this species. P. 105

Hesperocidaris perplexa H. L. Clark. Hypotype (California Academy of Sciences), from same location as specimen
shown in fig. 6. Length 21.1 mm.; maximum diameter 2.8 mm. Spine, lacking distal end. P. 105

Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 4.
Height 19.5 mm.; maximum diameter of corallum 9.3 mm. P. 84

Hesperocidaris perplexa H. L. Clark. Hypotype (California Academy of Sciences), from Loc. 12163 (CAS), Pacific
Beach, San Diego, California. Spine. Length 31 mm.; maximum diameter 3 mm. P. 105

. Hesperocidaris perplexa H. L. Clark. Hypotype (California Academy of Sciences), from same locality as specimen

shown in fig. 6. Spine (incomplete). Length 26.6 mm.; maximum diameter 2.5 mm. P. 105

. Encope tenuis Kew. Side view of specimen shown on plate 23, figs. 7, 13. Anterior end toward the right. P. 126
. Hesperocidaris perplexa H. L. Clark. Hypotype (San Diego Society of Natural History), from Pacific Beach, San

Diego, California. Maximum length of specimen 32.4 mm. Plates with primary and secondary tubercles. P. 105

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from the same locality as specimen shown

in fig. 4. Height 16.4 mm.; maximum diameter of calice 5.6 mm. P. 84

. Hesperocidaris perplexa H. L. Clark. Hypotype (California Academy of Sciences), from same locality as specimen

shown in fig. 6. Spine (incomplete). Length 18.3 mm.; maximum diameter 2.7 mm. P. 105

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in

fig. 4. Height 14.2 mm.; maximum diameter of calice 6.8 mm. P. 84

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 4.

Height 12 mm.; maximum diameter of calice 7.3 mm. P. 84

. Balanophyllia elegans Verrill. Hypotype (Los Angeles County Museum), from same locality as specimen shown in fig. 4.

Height 17 mm.; maximum diameter of calice 6 mm. P. 84

. Lovenia hempkilli Israelsky. Hypotype (Los Angeles County Museum), from Loc. 122 (LAM), 20 to 30 feet

below end of Loring Street, Pacific Beach, San Diego, California. Length 82 mm.; width 62 mm.; height 22 mm.
Aboral surface. P. 130

. Eucidaris cf. E. thouarsii Valenciennes. Hypotype (Los Angeles County Museum), from same locality as specimen

shown in fig. 4. Spine (incomplete). Length 27 mm.; maximum diameter 5.2 mm. P. 103

. Eucidaris cf. E. thouarsii Valenciennes. Hypotype (Los Angeles County Museum), from same locality as specimen

shown in fig. 4. Spine. Length 30 mm.; maximum diameter 3.4 mm. P. 103

. Eucidaris cf. E. thouarsii Valenciennes. Hypotype (Los Angeles County Museum), from same locality as specimen

shown in fig. 4. Spine (incomplete). Length 25 mm.; maximum diameter 3.7 mm. P. 103

. Eucidaris cf. E. thouarsii Valenciennes. Hypotype (Los Angeles County Museum), from same locality as specimen

shown in fig. 4. Spine (incomplete). Length 21 mm.; maximum diameter 3.6 mm. P. 103

PLaTEe 24

Marine PLIOCENE OF SAN Dirco, CALIFORNIA

Fic.

Fic.
Fic.
Fic.

Fic.

Fic.

EXPLANATION OF PLATE 25

Spatangus rarus Israelsky. Holotype (No. 917, California Academy of Sciences), from Loc. 547 (CAS), Pacific Beach,
San Diego, California. Length 72.5 mm.; width 77.0 mm.; height 29.3 mm. Aboral surface. P. 128

Spatangus rarus Israelsky. Oral surface of specimen shown in fig. 1.
Spatangus rarus Israelsky. Side view of specimen shown in figs. 1 and 2. Anterior end toward the right.

Encope tenuis Kew. Hypotype (San Diego Society of Natural History), from 31st Street and Logan Avenue, San
Diego, California. Length approximately 74 mm. Aboral surface. P. 126

Brisaster townsendi woynari Hertlein and Grant, new subspecies. Paratype (Los Angeles County Museum), from Loc.
107 (LAM), clay quarry at end of Arroyo Drive, San Diego, California. Length 92 mm.; width 91.8 mm.; height
35.5 mm. Aboral surface. P. 132

Merriamaster pacificus Kew. Aboral surface of specimen (slightly crushed) shown on plate 26, fig. 11.

Marine PLIOCENE OF SAN DrEGO, CALIFORNIA PLaTE 25

Fic.

Fic.
Fic.
Fic.

Fic.
Fic.

Fic.

Fic.

Fic. 9

Fic.
Fic.

EXPLANATION OF PLATE 26

Brisaster townsendi woynari Hertlein and Grant, new subspecies. Holotype (Los Angeles County Museum), from Loc.
107 (LAM), clay quarry at end of Arroyo Drive, San Diego, California. Length 91.5 mm.; width 90 mm.; height
34.5 mm. Aboral surface. A portion of the right side of this specimen is covered with hard concretionary sandstone. P. 132

Brisaster townsendi woynari Hertlein and Grant, new subspecies. Posterior end of specimen shown in fig. 1.
Brisaster townsendi woynari Hertlein and Grant, new subspecies. Oral surface of specimen shown in figs. | and 2.

Echinometra sp. Hypotype (California Academy of Sciences), from Loc. 1413 (CAS), Pacific Beach, San Diego, Cali-
fornia. Maximum diameter 19.2 mm.; height 8.3 mm. Side view. P. 114

Echinometra sp. Oral surface of the specimen shown in fig. 4.

Arbacia incisa A. Agassiz. Hypotype (California Academy of Sciences), from Pacific Beach, San Diego, California.
Diameter 7.6 mm.; height 3.8 mm. Side view. P. 108

Dendraster ashleyi ynezensis Kew. Hypotype (Los Angeles County Museum), side view of specimen shown on plate
21, fig. 5. Anterior end toward the right. P. 118

Arbacia incisa A. Agassiz. Aboral surface of specimen shown in figs. 6 and 10.

Dendraster ashleyi Arnold. Side view of specimen shown in plate 21, fig. 6.

. Arbacia incisa A. Agassiz. Oral surface of specimen shown in figs. 6 and 8.
Mle

Merriamaster pacificus Kew. Hypotype (Los Angeles County Museum), from Loc. 122 (LAM), 20 to 30 feet below
end of Loring Street, Pacific Beach, San Diego, California. Length 24.3 mm.; width 22.8 mm.; height 6.4 mm. Oral
surface of a slightly crushed specimen. See also plate 25, fig. 6. P. 124

Marine PLIOCENE OF SAN D1EGO, CALIFORNIA

PLATE

26

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HARVARD
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1898 — 1972

ThE GEOLOGY

AND PALEONTOLOGY

OF THE MARINE PLIOCENE

OF SAN DIEGO, CALIFORNIA
(PALEONTOLOGY: PELECYPODA)

LEO GEORGE HERTLEIN
CALIFORNIA ACADEMY OF SCIENCES

AND

U.S. GRANT, IV
UNIVERSITY OF CALIFORNIA AT LOS ANGELES

SAN DIEGO
SOCIETY OF NATURAL HISTORY

MEMOIR 2 (PART 2B)

1972

SAN DIEGO SOCIETY OF NATURAL HISTORY MEMOIRS

Memoir 2 (Part 2B), pages 135-411, frontispiece
text-figures 7-13, plates 27-57
Issued July 21, 1972

LEO GEORGE HERTLEIN

1898-1972

Leo George Hertlein died on 15 January 1972. Dr. Hertlein
was Emeritus Curator of Geology at the California Academy of Sciences,
where he had worked from 1925 until his retirement in 1970. The
October 1970 issue of The Nautilus honors Dr. Hertlein on the occasion
of his retirement, and contains a biographical sketch, a list of his publi-
cations, a list of the taxa he proposed and those taxa proposed in his
honor.

PUBLISHED WITH FINANCIAL AID

FROM THE

W. W. WHITNEY PUBLICATIONS ENDOWMENT

AND BY DONATIONS FROM

Century City Scientific Corporation
Edwin W. Pauley Foundation
Standard Oil Company Of California
Trade Printing Company, Inc.

Dr. R. Tucker Abbott Dr. Hans G. Kugler

Dr. Warren O. Addicott Dr. Harry S. Ladd

Dr. Richard C. Allison Dr. George E. Lindsay
Dr. William A. Burns Mr. Frederic F. Mellen
Dr. Ian Campbell Dr. and Mrs. George W. Moore
Dr. C. C. Church Dr. Norman D. Newell
Mr. Bernard D. Cirlin Dr. David Nicol

Dr. Eugene V. Coan Dr. Katherine V. W. Palmer
Dr. James E. Crouch Dr. Willis P. Popenoe

Dr. J. Wyatt Durham Dr. Horace G. Richards
Dr. William K. Emerson Dr. Robert R. Robertson
Dr. Louis R. Fletcher Dr. Peter U. Rodda

Dr. A. Eugene Fritsche Dr. Joseph Rosewater
Mrs. Margaret M. Hanna Mrs. Cecelia D. Ross

Dr. William G. Heaslip Mrs. LouElla Saul

Dr. Carole S. Hickman Dr. Donald R. Shasky
Dr. Alan Horowitz Mr. Allyn G. Smith

Dr. and Mrs. Carl L. Hubbs Dr. Robert J. Stanton
Mr. Morris K. Jacobson Dr. Henryk B. Stenzel
Mr. Richard I. Johnson Dr. James W. Valentine
Dr. Peter Jung Dr. Thomas R. Waller
Dr. Saburo Kanno Mr. Druid Wilson

Mr. H. E. Karges Dr. Edward C. Wilson
Dr. A. Myra Keen Mr. Wendell P. Woodring

Mr. George L. Kennedy

a

CONTENTS

Foreword :
New Generic and Subgeneric Names
New Specific and Subspecific Names
Abbreviations . 5
References and Supplementary Data
Phylum Mollusca Linnaeus ‘
Class Pelecypoda Goldfuss .
Subclass Prionodesmata Neumayr
Order Palaeotaxodontida Korobkov.
Superfamily Nuculacea Gray .
Family Nuculidae Gray. . :
Family Nuculanidae H. and A. Adams :
Subclass Pteriomorphia Beurlen . of te
Order Eutaxodontida Grobben
Superfamily Arcacea Oken
Family Arcidae Oken . . :
Family Glycymerididae Newton :
Order Dysodontida Neumayr (Fischer).
Superfamily Mytilacea Rafinesque .
Family Mytilidae Rafinesque .
Order Isodontida Dall :
Superfamily Pectinacea Rafinesque .
Family Pectinidae Rafinesque.
Superfamily Limacea Rafinesque
Family Limidae Rafinesque
Superfamily Ostreacea Rafinesque .
Family Ostreidae Rafinesque .
Superfamily Anomiacea Rafinesque.
Family Anomiidae Rafinesque
Subclass Teleodesmata Dall
Order Pachyodontida Steinmann
Superfamily Chamacea Blainville.
Family Chamidae Blainville
Order Heterodontida Neumayr
Superfamily Crassatellacea Menke
Family Crassatellidae Menke .
Superfamily Carditacea Fleming .
Family Carditidae Fleming .
Superfamily Leptonacea Gray. .
Family Kelliidae Forbes and Hanley
Family Montacutidae W. Clark
Family Sportellidae Dall
Superfamily Lucinacea Fleming .-
Family Lucinidae Fleming .
Family Diplodontidae Dall.
Family Thyasiridae Dall
Superfamily Cardiacea Oken .
Family Cardiidae Oken . :
Superfamily Veneracea Rafinesque .
Family Veneridae Rafinesque -
Family Petricolidae D’Orbigny
Superfamily Tellinacea Oken .
Family Tellinidae Oken .
Family Semelidae Stoliczka
Family Donacidae Fleming
Family Garidae Stoliczka . P
Family Solecurtidae D’Orbigny .

143
143
143
143
143
144
144
144
144
144
144
198
152
152
152
152
158
161
161
161
171
171
uefa
214
214
215
215
222
222
226
226
226
226
228
228
228
229
229
234
235
239
241
242
242
251
254
258
258
264
264
282
284
284
299
302
303
305

Superfamily Solenacea Gray .
Family Solenidae Gray . :
Superfamily Mactracea Bowdich .
Family Mactridae Bowdich
Order Asthenodontida Dall :
Superfamily Myacea Goldfuss.
Family Myidae Goldfuss
Superfamily Corbulacea Bowdich
Family Corbulidae Bowdich
Superfamily Hiatellacea Gray .
Family Hiatellidae Gray

Superfamily Pholadacea Rafinesque.

Family Pholadidae Rafinesque

Family Teredinidae Rafinesque .

Subclass Anomalodesmata Dall
Order Eudesmodontida Cox

Superfamily Pandoracea Rafinesque

Family Pandoridae Rafinesque
Family Periplomatidae Dall
Family Thraciidae Stoliczka
Order Poromyoida Pelseneer .
Superfamily Poromyacea Dall
Family Poromyidae Dall .
Family Cuspidariidae Dall .

Family Verticordiidae Stoliczka .

References and Supplementary Data
List of Localities aes
Index...

Plates 27 to 57

FOREWORD

This portion of this monograph deals with the
Pelecypoda of the San Diego Formation. The major
collections upon which the present paper is based are
chiefly those in the California Academy of Sciences, the
Los Angeles County Museum, San Diego Society of
Natural History, and the University of California at Los
Angeles. These were supplemented by additional material
from the collections at Stanford University and San Diego
State College.

Special acknowledgment is due Mr. George P.
Kanakoff, Los Angeles County Museum, who generously
lent an extensive collection which he and his associates as-
sembled in the San Diego area. This collection furnished
the basis for records of many species not previously re-
ported from the San Diego formation. A collection earlier
loaned by Mrs. Kate Stephens, former Curator of Marine
Invertebrates at the San Diego Society of Natural History,
was supplemented by additional specimens sent by Dr.
Edward C. Wilson, former Curator of Invertebrates (now
with Los Angeles County Museum of Natural History),
and Mr. Emery P. Chace, former Curator of Mollusks, in
that institution.

Collections in greater part assembled by the late
Ernest H. Quayle, which are the property of the San Diego
Society of Natural History and of the University of
California at Los Angeles, were lent by Mr. Takeo Susuki
and Dr. Willis P. Popenoe of the latter institution.

The present paper could not have appeared in its
present form without the aid and cooperation of many
individuals. We are especially grateful to Dr. G D. Hanna,
Curator of the Department of Geology, to Barry Roth,
Curatorial Assistant in the same Department, and to Allyn
G. Smith, Associate Curator of the Department of In-
vertebrate Zoology, California Academy of Sciences, who
aided with advice and constructive criticism on many oc-
casions. Ray Brian, librarian in the same institution aided
us by making available certain of the literature pertinent
to this study, and Dr. Anatole Loukashkin, Research
Associate in the Department of Ornithology and Mam-
malogy, kindly furnished translations of some articles
published in the Russian language. Others who aided in
various ways include: Dr. A. Myra Keen and Dr. Eugene
Coan, Stanford University; Dr. J. Wyatt Durham, and Mr.
Joseph H. Peck, Jr., University of California, Berkeley;
Dr. Joshua L. Bailey, Jr., San Diego Society of Natural
History; the late Dr. Edwin C. Allison, and Professor E.
Dean Milow, San Diego State College; Dr. Harald A.
Rehder, Dr. G. Arthur Cooper, and Dr. Joseph Rosewater,
United States National Museum; Dr. William K. Emerson,
American Museum of Natural History; Dr. R. Tucker
Abbott and Dr. Robert R. Robertson, Academy of Natural
Sciences of Philadelphia; Dr. Ruth Turner, Museum of
Comparative Zoology, Harvard University; Mr. F. Stearns
MacNeil, Fort Myers, Florida; Mrs. Ellen Moore, United
States Geological Survey, San Diego, California; Dr.
Hendryk B. Stenzel, Shell Development Company, Houston,
Texas; Dr. André Franc, Laboratoire de Malacologie,
Museum National d’Histoire Naturelle, Paris. The aid of
the other individuals will be acknowledged in the ap-
propriate places in the text.

Most of the photographs used for illustrations on the
plates were made by Mr. Maurice C. Giles, Photographer,

California Academy of Sciences, but photographs of some
of the small specimens were furnished by the late Dr. G D.
Hanna and Allyn G. Smith of the same institution.

The line drawings from which text figures 7, 8, 9,
10, and 13 were made, were drawn by the late Ernest H.
Quayle. Text figures 11 and 12 are from drawings by
Mrs. Dorothy Ludlow. The typescript was prepared by
Mrs. Ludlow and Mrs. Enid Cook. Mrs. Margaret Hanna
kindly retouched many of the photographs.

The cost of photography was provided by a grant,
No. G17939, National Science Foundation. The authors
are grateful to the individuals whose efforts facilitated
this grant, and especially to Dr. David D. Keck, former
Program Director, Dr. Walter H. Hodge, present Program
Director, and Miss J. Frances Allen, Associate Program
Director for Systematic Biology.

NEW GENERIC AND SUBGENERIC NAMES

Axinola, new subgenus
Trusella, new genus

NEW SPECIFIC AND SUBSPECIFIC NAMES

Nucula (Ennucula) balboana, new species

Mytilus (Crenomytilus) coalingensis sternbergi, new sub-
species

Chlamys (Chlamys) hastata ellisi, new subspecies

Chlamys (Argopecten) abietis abbotti, new subspecies

Lima (Limaria) orcutti, new species

Aligena diegoana, new species

Bornia frankiana, new species

Dosinia ponderosa diegoana, new subspecies

Chione allisoni, new species

Chione kanakoffi, new species

Psephidia stephensae, new species

Semele ashleyi, new species

Thracia kanakoffi, new species

ABBREVIATIONS

Abbreviations following locality numbers cr speci-
men numbers refer to the following institutions:

(ANSP) — Academy of Natural Sciences of Philadelphia

(CAS) — California Academy of Sciences

(LAM) — Los Angeles County Museum Invertebrate
Paleontology

(SD) — San Diego Society of Natural History

(SDSC) — San Diego State College

(SU) — Stanford University

(UC) — University of California (Berkeley)

(UCLA) — University of California at Los Angeles

(USGS) — United States Geological Survey

(USNM) — United States National Museum

REFERENCES AND SUPPLEMENTARY DATA
All references and supplementary data are numbered

consecutively within the text (in parentheses); these fol-
low the main body of the text, starting on page 345.

144

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

PHYLUM MOLLUSCA LINNAEUS

CLASS PELECYPODA GOLDFUSS

The Pelecypoda from the San Diego formation
identified in the present study, are here arranged in 4
subclasses, 8 orders, 22 superfamilies, 39 families, 82
genera and 144 species and subspecies of which 10 are
not positively identified but are compared [cf. or aff.]
with known species and 2 additional ones are cited as to
genus only. One genus, one subgenus, 9 species and 4 sub-
species are described as new. The occurrence of 11 species,
one cited only as to genus, reported by other authors as
occurring in the San Diego Formation, was not confirmed
during the present faunal study.

The systematic arrangement in general is a combina-
tion derived from that of Dall (1)* and that of Thiele (2)
with minor modifications from Cox and Newell. Families
and superfamilies both are attributed to the first author
who mentioned an acceptable latinized suprageneric
category applicable to the group. Da Costa (3) was one of
the earliest authors to apply latinized family categories
to suprageneric groups of pelecypods. For example,
“Family 9, is the Tellinae of Tellens.”” These denomina-
tions appear to be as acceptable nomenclatorially for
suprageneric categories as are names used in the vernacular
plural by Blainville and by Lamarck, such as “Les
Tellinacées” which was latinized by later authors to
Tellinidae and Tellinacea. A volume by Haas (4) contains
a wealth of information concerning the classification and
biology, including an extensive bibliography dealing with
peleecypods. A work by France (5) also deals with a general
treatment of this class. Publications by Habe (6),
Korobkov (7), Cox (8), Newell (9) and Vokes (10) also
are useful in ascertaining modern systematic arrangements
of Cenozoic bivalves.

A recent publication, part of “Treatise on Inverte-
brate Paleontology,” (11) contains an important discussion
of the general features, and a comprehensive, systematic
treatment of the supraspecific categories of the Pelecypoda.
A paper by Boggild (12) deals with the shell structure of
mollusks and a paper by Oberling (13) contains a dis-
cussion of the structural features of pelecypod shells.

The maximum depth ranges cited for the genera and
species in this paper are based upon published records (14).
These, however, can only be considered as representing
approximate depths to which members of the genera may
be found. Many of these records, where taken from the
earlier literature, undoubtedly refer to the genera in a
broad sense.

SUBCLASS PRIONODESMATA NEUMAYR
ORDER PALAEOTAXODONTIDA KOROBKOV
SUPERFAMILY NUCULACEA GRAY (15)
FAMILY NUCULIDAE GRAY (16)

Shell equivalve, up to 50 mm in length; roughly
trigonal or oval in outline; inequilateral; posterior side
short, often truncate; anterior side longer than posterior,
with anterior extremity rounded. Beaks posterior,
*All references and supplementary data are numbered
consecutively within the text (in parenthesis); these
follow the main body of the text, starting on page 345.

opisthogyrate. A true lunule (behind the umbones)
wanting; the pseudo-lunule, though sometimes lanceolate,
is seldom well-defined. Below the beaks the escutcheon
(occupying the position of the lunule of many pelecypods)
is often heart-shaped. Prodissoconchs smooth. Sculpture,
when present, consists of concentric ribs only, concentric
ribs and radial ribs; bifurcating radial ribs, or modifications
and combinations of these. Inner ventral margins smooth
or denticulate (crenulate or pectinate). Dentition taxodont,
with the longer row of teeth generally extending over the
chondrophore (ligament-support). No external ligament,
but an internal resilium. Pallial line entire. Shells with
nacreous interiors (at least when the animal was alive);
in many, if not all, species there is a differentiation of shell
material, but no prismatic layer. Shells not gaping, and
commonly each exhibits two subequal adductor muscle
sears and additional muscle scars. The type genus is
Nucula Lamarck, 1799. (Schenck, 1934.) Ordovician to
Recent.

Remarks. — Members of this large family first
appeared early in the Paleozoic era. The pearly inner
layer of the shell and the presence and arrangement of the
small, numerous, curved, taxodont teeth on the hinge sug-
gest an early origin for this group. The gill structure of
Recent forms is protobranch.

Schenck (17) discussed the classification of this
family, as did Cox (18) who dealt especially with the
derivation of the Mesozoic and Paleozoic representatives.
The structure of the shell and the classification of this
group was discussed recently by Van de Poel (19).

Key to Genera and Subgenera of Nuculidae

A. Shell with divaricate sculpture . Acila
a. Valves with a groove parallel to
posterior margin . (subgenus) Acila s. s. (20)
aa. Valves lacking groove parallel to
posterior margin . (subgenus) Truncacila

B. Shell smooth or with radial or
cancellate sculpture . Nucula
a. Inner margin of shell with denticles

b. Concentric sculpture coarse,
lamellate (subgenus) Lamellinucula
bb. Concentric sculpture fine, not
lamellate (subgenus) Nucula s. s. (20)

aa. Inner margin of shell smooth . (subgenus) Ennucula
GENUS NUCULA LAMARCK

Nucula Lamarck, Mém. Soe. d’Hist. Nat. Paris, p. 87,
1899. Sole species: Arca nucleus Linnaeus. — Grant
and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p.
110, 1931. ‘Type (by monotypy), Arca nucleus
Linnaeus.” — Schenck, Bull. Mus. Roy. d’Hist. Nat.
Belgique, Vol. 10, No. 20, p. 18, 1934. “(Type by
monotypy: Arca nucleus Linné).” — Hertlein and

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Strong, Zoologica, Vol. 25, Pt. 4, p. 379, 1940. “Type
(by monotypy): Arca nucleus Linnaeus.”

Type species (by monotypy). — Arca nucleus
Linnaeus [Syst. Nat., ed. 10, p. 695, 1758. “Habitat in
Europa.” Illustrated by Schenck, 1934, pl. 1, fig. 8;
pl. 3, fig. 2; pl. 4, figs. 4, 4a, 4b; pl. 5, figs. 1, la. —
Schenck, Proc. Malacol. Soc. London, Vol. 21, Pt. 4,
fig. 1 (p. 260), March, 1935].

Range. — Jurassic to Recent. Recent in all seas;
greatest number in temperate and boreal regions, from a
few meters to a depth of over 3658 meters (2000 fathoms).

Description. — Shell closed, not gaping; profile
ovate-trigonal; a “pouting” of the escutcheonal area,
which the radial ribs do not cross; beaks opisthogyrate,
appressed; prodissoconch unornamented; radial ribs faint,
low, wide and flat, often difficult to see on the middle
part of the shell, but they are more distinct near the
ventral margin where they form the ‘‘pectinate margin’’;
interspaces narrow, about one-tenth the width of the ribs;
interior nacreous; pallial line simple; two subequal adductor
muscle sears and additional muscle scars; longer (anterior)
row of teeth arched, with 16+ to 24+ teeth; the shorter
(posterior) row straight with 7+ to 11+; axis of chondro-
phore forms an arc of a circle of which the arcuate dorsal
margin is a part. (Schenck, 1934).

Remarks. — Species of this genus are generally small,
many of them do not exceed 10 mm in length. Nucula
mirifica Dall (21) living in the waters of Japan was said by
its author to be probably the largest living smooth Nucula
known. It attains a length of 36 mm. Large specimens
of Nucula compressa Philippi from the Chattian (late
Oligocene) of Belgium were reported by Schenck to be
29.3 mm long.

Trueman (22) published the results of a study of the
ligament of Nucula. Ford (23) pointed out that the con-
centric rings of the shell of Nucula nitida do not lend
themselves to a simple interpretation of the rate of growth.
The habits of two species of this genus living in north
European waters were described by Allen (24).

Schenck in 1934 stated that over one thousand
specific names have been associated with the genus Nucula.
A few species have been described from Tertiary strata of
western North America but only two of those have been
reported from beds of Pliocene age. About 20 to 22
species are known from west American waters between
Bering Sea and Cape Horn.

SUBGENUS ENNUCULA IREDALE

Ennucula Iredale, Rec. Australian Mus., Vol. 18, No. 4,
pp. 202, 231, June 29, 1931. ‘Type Nucula obliqua
Lamarck.”’ — Schenck, Bull. Mus. Roy. d’Hist. Nat.
Belgique, Vol. 10, No. 20, p. 37, June, 1934. ‘‘(Type:
Nucula obliqua Lamarck.)” — Hertlein and Strong,
Zoologica, Vol. 25, Pt. 4, p. 382, December 31, 1940.
“Type (by original designation): Nucula obliqua
Lamarck.”

Type species (by original designation). — Nucula
obliqua Lamarck [Hist. Nat. Anim. s. Vert., Vol. 6, p. 59,
1819. “Habite les mers australes, au Cap aux Huitres.”’
Illustrated by Schenck, 1934, pl. 3, figs. 4, 4a, 4b; pl. 4,
figs, 3, 3a, 3b. Australia, Recent].

Range. — Miocene (and probably earlier) to Recent.

Original descriptions. — The type species of Nucula is

145

nucleus Linné, a European species which differs ap-
preciably from antipodean shells so classed, the latter
having a notably oblique chondrophore, above which the
teeth become much smaller, and the angle of opposition
of the two rows of teeth is scarcely marked; further, the
edge of the European shell is strongly denticulate,
whereas ours is practically smooth. (Iredale, 1931.)

Remarks. — The similarity of Ennucula to Leionu-
(25), which latter genus was described by Quenstedt one
year earlier, was mentioned by Schenck (1934, p. 35)
and later by Ichikawa and Maeda (26).

Schenck assigned subgeneric status to Ennucula
which he placed under the genus Nucula. Van de Poel,
more recently, considered the species of Nuculidae with
non-radial structure to be referable to the genus Nuculoma
Cossman (see Schenck, 1934, p. 26, pl. 4, figs. 5, 5a, 5b,
5c) whose type is Nucula castor d’Orbigny, a Jurassic
species. On this basis he assigned Ennucula subgeneric
status under Nuculoma. We have not studied specimens
of N. castor and for the present at least, we leave En-
nucula in the category assigned to it by Schenck.

About 20 species were placed in Ennucula by
Schenck and he listed thirteen additional species which
may be referable to this subgenus. Six species from the
Cenozoic of western North America have been referred to
Ennucula. One new species from the Pliocene of San
Diego is added in the present paper.

Nucula (Ennucula) balboana n. sp.
Plate 27, Figures 1, 2, 3, 4

“Nucula, sp. n. according to Dr. Cooper,” Dall, Proc.
Calif. Acad. Sci., Vol. 5, p. 297, December, 1874.
“Well at San Diego.” — Orcutt, West Amer. Sci., Vol. 6,
whole No. 46, p. 85, August, 1889. Dall’s (1874)
record cited. — Orcutt, cited by Ellis in Ellis and Lee,
U. S. G. S., Water Supply Paper 446, p. 59, 1919.
Orcutt’s citation of Dall’s record (1874) cited. —
Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, p. 48, 1944. Dall’s record cited. (Not
Nucula exigua Sowerby).

Holotype and paratypes in the California Academy
of Sciences Department of Geology Type Collection, from
the San Diego well in Balboa Park, San Diego, California;
H. Hemphill, collector; Pliocene.

Range. — Known only from the type locality.

Descriptions. — Shell ovately triangular, smooth,
beaks opisthogyrate, placed near posterior end, a lanceolate
depressed area beneath them; the posterior margins of the
valves slightly projecting; a narrow area along the anterior
dorsal margin slightly depressed; anterior margin broadly
rounded, the anterior end elliptically rounded, the poster-
ior end slightly rounded and abruptly truncated; surface of
valves with fine concentric lines of growth, toward the
anterior margin with occasional minute constrictions;
inner margin of shell smooth and devoid of denticles.
Portions of two paratypes reveal the presence of about 18
teeth in the anterior series and about 8 or 9 in the posterior
series. The chondrophore projects obliquely anteriorly.
Dimensions of holotype: length, 13.4 mm; height,
10.7 mm; convexity (both valves together slightly gaping
due to enclosed sediment), 7.2 mm.

Remarks. — The species here described as new
closely resembles Nucula quirica Dall (27) but differs in

146

that the shell is more elongate in proportion to the height,
the anterior margin is correspondingly less broadly
rounded, and so far as known there is no trace of fine
radial striae on the interior of the valves.

Schenck (28) considered N. quirica to be a probable
synonym of Nucula bellotii A. Adams (29) but judging
from his illustrations (30) of that species the shell is less
abruptly truncated posteriorly and the anterior dorsal
margins of the valves are more inflated than that of Dall’s
species.

The present specimens, collected by Henry Hemphill
from the San Diego well, are probably from the original
lot which Dall identified as a new species of Nucula which
“Looks much like N. tenuis.”

SUBGENUS LAMELLINUCULA SCHENCK

Lamellinucula Schenck, Jour. Paleo., Vol. 18, No. 1,
p. 97, January, 1944.

Type species (by original designation). — “‘Nucula
tamatavica Odhner (1943, p. 206), new name for Nucula
rugosa Odhner (1919, pp. 23-24, pl. 2, figs. 15-18); Recent,
Madagascar.” [See Odhner, K. Svensk Vetenskaps Arkiv
for Zool., Bd. 12, No. 6, p. 23, pl. 2, figs. 15-18, 1919.
Also illustrated by Schenck, 1944, p. 98, fig. 1.]

Range. — Eocene (31) to Recent. Recent, world-
wide, in 5 to 219 meters (3 to 120 fathoms), questionable
below 1829 meters (1000 fathoms) according to Schenck.

Original description. — The subgenus is proposed for
nuculid pelecypods ranging in length up to about 25.0 mm;
shell closed, not gaping; dorsal margin straight to gently
arched; anterior extremity bluntly rounded (see fig. 1);
ventral margin convex; posterior margin straight to con-
vex; lunule and escutcheon indistinct to moderately well
defined; beaks inturned, opisthogyrate; interior nacreous;
taxodont dentition consisting of about 12 to 26 teeth in
the anterior (long) series, 4 to 12 in the posterior (short)
row; chondrophore distinct, sometimes heavy; two sub-
equal adductor muscle sears and accessory sears as in other
members of the family; pallial line entire; inner ventral
margin denticulate (crenulate, crenate); incised, lamellate
concentric sculpture more conspicuous than radial ribs or
striae; from two to eight concentric ribs per millimeter.
(Schenck.)

Remarks. — Twenty species and subspecies, described
under the genus Nucula, were referred to Lamellinucula
by Schenck and he mentioned thirteen others which may
be referable to this category.

Glibert and Van de Poel (Mém. Inst. Roy. Sci. Nat.
Belgique, Deuxieme Sér., Fase. 77, p. 15, 1965) suggested
the possibility that the type of ornamentation on
Lamellinucula may be polyphyletic.

Nucula (Lamellinucula) exigua Sowerby
Plate 27, Figures 5, 6

Nucula exigua Sowerby, Proc. Zool. Soe. London for
1832, p. 198 (issued March 13, 1833). — Sowerby,
Conch, Illustr., Nuculae, Catalogue, Pt. 16, p. 6, pl. 16,
figs. 24, 24*, issued January 18, 1833. (Reprinted
Cat., p. 6, 1841.) ‘Bay of Caraccas.” — Hanley, Thes.
Conch., Vol. 3, p. 154, pl. 229, (Nuculidae, pl. IV), fig.
136, 1860. “Bay of Caracas, W. Columbia.” — Dall,
Proc. U. S. Nat. Mus., Vol. 1, p. 28, 1878. “‘well-

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

digging in stratum B2.” Pliocene. Other localities
(pp. 11, 27), probably Pleistocene. — Cooper, Calif.
State Mining Bureau, Seventh Ann. Rept. State
Mineralogist, Vol. 7, p. 254, 1888. “Pl. — San Diego
well.” — Orcutt, West Amer. Sci., Vol. 6, whole No.
46, p. 86, August, 1889. Dall’s record (1874) cited.
— Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p.
577, 1898. “San Diego, California, well.” “Pliocene.”
— Orcutt, quoted by Ellis in Ellis and Lee, U.S. G.S.,
Water Supply Paper 446, p. 60, 1919. Dall’s record
(1874) cited — I. S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 13, 1924. “In the
Pliocene of San Pedro and San Diego, California.”
Also Recent.

Nucula (Nucula) exigua Sowerby, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 111, 1931. “San
Diego well’ (Dall’s record, 1898, cited), Pliocene.
Also cited from Merced and Wildcat Formations and
Pleistocene and Recent. — Schenck, Jour. Paleo.,
Vol. 13, No. 1, p. 36, pl. 6, figs. 1-8, 11, 1939. Recent.
—Hertlein and Strong, Zoologica, Vol. 25, Pt. 4, p. 381,
pl. 1, figs. 4, 5, 1940. Corinto, Nicaragua, Recent.
Also earlier records.

Nucula exiqua Sowerby, Palmer, Geol. Soc. Amer., Mem.
76, p. 61, pl. 1, figs. 6, 7, 1958. Syntype of “N.
suprastriata Cpr.”’, from ‘“ ‘Catalina 30 fms. Cooper’.”
Not Nucula suprastriata Carpenter in Arnold, 1903.

Nucula (Nucula) exiqua Sowerby, Olsson, Mollusks of
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New
York), p. 56, pl. 1, figs. 2, 2a, 2b, 10, 10a, 1961.
Lower California to Peru.

Type specimen. — British Museum (Natural History).

Type locality. — “Hab. ad Columbiam Occidentalem
(Bay of Caraceas).”” [Ecuador, Lat. 00° 35’ S.] “A single
specimen found in sandy mud at nine fathoms depth.”

_ Range. — Middle Pliocene to Recent. Recent from
Bahia Tortolo (Turtle Bay), Lower California, to the Gulf
of California, and south to Ecuador, in 16 to 24 meters
(9 to 13 fathoms); 1207 to 1895 meters (660 to 1036
fathoms) (Dall).

Occurrence in San Diego Fm. — U.C.L.A. 312.

Original description. — Nuc. testa parva, oblique
ovata, albicante, pellucida, concentrice sulcata; latere
postico longiore, subacuminato, antico brevissimo: long.
0.2, lat. 0.1, alt. 0.15 poll. (Sowerby.)

Remarks. — This species was reported by Dall from
diggings of the San Diego well and that record was cited
by several authors.

One left valve and two imperfect right valves, one of
which is about 5 mm in altitude, are present in the col-
lections from near the United States-Mexico boundary.
These retain traces of radial striae, crossing the stronger
concentric ribbing, over most of the surface of the valves.
This feature, however, varies in a series of Recent speci-
mens of this species as does the amount of escutcheonal
projection.

Nucula suprastriata Carpenter in Arnold (32), a
similar species or subspecies, is said to differ from N.
exigua in the greater size (up to 7 mm in length), the more
impressed lunule and escutcheon, and in that the radial
sculpture usually is present only toward the base of the
valves. These differences, as mentioned by Schenck, are
found to be less constant when a large series of specimens
is examined. Schenck concluded that greater size is the

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

most reliable criterion for separating N. suprastriata from
N. exigua.

A consideration of the foregoing in connection with
study of the present fossils from the San Diego formation
leads us to refer them to N. exigua.

Adequate discussion and illustration of Recent
specimens of Nucula exigua have been given by Schenck
and by Hertlein and Strong.

Nucula paytensis A. Adams (33) as pointed out by
Hertlein and Strong, apparently is more rounded in out-
line and the escutcheon area is more projecting than that
of N. exigua. Schenck (1944, p. 98) considered it to be a
synonym of N. exigua and Olsson (1961, p. 56) suggested
that intergradation between the two may occur.

Nucula vieta Guppy described from strata of late
Miocene age in Trinidad is a very similar species (see Jung,
Bull. Amer. Paleo., Vol. 55, No. 247, p. 316, pl. 13, figs.
4-7, 1969).

Nucula cahuitensis Olsson (34) described from strata
of Miocene age in Costa Rica, was compared by its author
with N. exigua.

Nucula venezuelana Weisbord (35) described from
beds of Pliocene age in Venezuela is another similar species.

GENUS ACILA H. AND A. ADAMS

Acila H. and A. Adams, Gen. Rec. Foss. Moll., Vol. 2,
p. 545, January, 1858. Species cited: ‘‘castrensis,
Hinds,” ‘“‘divaricata, Hinds,’ ‘mirabilis, Adams and
Reeve.” — Kobelt, Illustr. Conchylienbuch, Bd. 2,
Lief. 10-11, p. 371, 1881. “‘Typus Nucula divaricata
Hinds (Taf. 109 Fig. 18).’”’ — Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 112, November 3,
1931. Type as designated by Stoliczka, 1871. —
Schenck, Geol. Soc. Amer., Spec. Papers No. 4, p. 23,
1936. Type as designated by Stoliczka, 1871.

Type species (designated by Stoliczka, Mem. Geol.
Surv. India, Palaeo. Indica, Ser. 6, Cret. Fauna South.
India, Vol. 3, pp. XXI, 325, 1871). — ‘“‘N. divaricata,
Hinds, is the type.”’ | Proc. Zool. Soc. London for 1843,
p. 97, issued December, 1843. ‘Hab. China Sea; from
eighty-four fathoms.” ‘Cab. Belcher.’ Illustrated by
Hinds, Zool. Voy. Sulphur, Moll., Pt. 3, p. 62, pl. 18, fig.
4, 1844 (January, 1845, on cover of Pt. 3). — Schenck,
1936, pl. 15, figs. 1-10, text fig. 8 (1, 2).]

Range. — Early Cretaceous (Aptian) to Recent.
Recent in Indo-Pacific waters at depths of about 9 to
1500 meters (5 to 820 fathoms) but usually in less than
914 meters (500 fathoms), in fine-grained sediment, and
bottom temperatures between 4.4° to 21.1° C. (40° to
70° F.) but species have been taken in 1.11° ©. (34.0° F.)
and 23.9° C. (75° F.).

Description. — Like Nucula but often larger (max.
length about 50 mm), the surface sculptured with a
characteristic pattern of parallel divaricating and more or
less radial riblets which appear as if stacked or packed close
together the main line of divarication extending from the
umbo across the middle of the shell disk to the ventral
margin, the peaks of their inverted V’s forming a line of
sharp, acute angles pointing toward the beak. A secondary
line of reversed divarication may be developed along the
posterior rostral side which forms a shallow sinus ending
in a slight bulge or pout at the margin. (Olsson, A. A.,
Mollusks of the Tropical eastern Pacific (Paleo. Res. Inst.:

147

Ithaca, New York), p. 57, 1961.)

Remarks: ‘The shells of this genus are closed,
equivalve, inequilateral and trigonal or ovate to quadrang-
ular in outline similar to Nucula. They attain a length of
about 50 mm and a height of often about 75 per cent of
the length. The beaks are opisthogyrate; interior nacreous;
dentition taxodont.

A thorough monographic study of Acila and its
species by Schenck (36) in 1936 has been the source of
most of our information concerning the ecology of this
group. According to Schenck Acila s. s. is known to range
from ‘‘Oligocene (?) to Recent.”

Key to Subgenera of Acila

A. Well defined rostral sinus present Acila s. s.

B. Well defined rostral sinus lacking Truncacila
SUBGENUS TRUNCACILA SCHENCK IN
GRANT AND GALE

Truncacila Schenck MS., in Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 115, November 3,
1931. — Schenck, Geol. Soc. Amer., Spec. Papers No. 4,
p. 23, 1936. “Genotype: Nucula castrensis Hinds, by
original designation.”

Type species (by original designation). — ““Type:
Nucula castrensis Hinds.”

Range. — Cretaceous to Recent.

Description. — Adult shell seldom exceeds 30
millimeters in length; trigonal; quadrangular or ovate in
outline; lacking the well-defined rostral sinus that
characterizes Acila, sensu stricto; one or more bifurcations
(divarications) of the radial ribs. (Schenck, 1936.)

Remarks. — Schenck listed 17 species and sub-
species definitely referable to Truncacila and several others
doubtfully belonging to this subgenus.

One species, the type of this subgenus, occurs in the
San Diego formation.

Acila (Truncacila) castrensis Hinds
Plate 27, Figures 7, 8,9, 10

Nucula castrensis Hinds, Proc. Zool. Soe. London for
1843, p. 98, issued December, 1843. — Hinds, Zool.
Voy. Sulphur, Moll., Pt. 3, p. 63, pl. 18, fig. 5, 1844
(January 1845 on cover of Pt. 3). — Reagan, Trans.
Kansas Acad. Sci., Vol. 22, p. 204, 1909. Quillayute
Formation, western Washington, Pliocene. Also
“Purisima-San Diego” formation in California. — J. P.
Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 3, p. 182,
1912. “San Diego-Purisima.” — I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, No. 1, p. 14,
pl. 5, fig. 11; pl. 37, figs. 1, 2, 1924. Recent. Also
“Pliocene” at “San Diego.’’ — Hertlein, Stanford Univ.
Bull., Ser. 5, No. 78, p. 84,1929. ‘San Diego Pliocene.”

Acila lyallii Baird, Dall, Proc. Calif. Acad. Sci., Vol. 5, p.
297, 1874. “Well at San Diego.” — Dall, Proc. U. S.
Nat. Mus., Vol. 1, No. 2, p. 28, 1878. ‘“‘well-digging in
stratum B2,” San Diego. — Orcutt, West Amer. Sci.,
Vol. 6, Whole No. 46, p. 85, August, 1889 (as Acila
lyalli). Dall’s record (1874) cited. — Orcutt, cited by
Ellis in Ellis and Lee, U. S. G. S., Water Supply Paper

148

446, p. 59, 1919 (as Acila lyalli). Dall’s record (1874)
cited. — Hertlein and Grant, Mem. San Diego Soc. Nat.
Hist., Vol. 2, Pt. 1, p. 48, 1944. Dall’s record (1874)
cited.

Acila castrensis Hinds, Cooper, Calif. State Min. Bur.,
Seventh Ann. Report of State Mineral. Vol. 7, p. 227,
1888. “San Diego well, “Pliocene.” — Hertiein and
Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2, Pt. 1,
p. 48, 1944. Quotation of Dall’s record (1874). — Wood-
ring, Stewart, and Richards, U. S. G. S., Prof. Paper
195, table opp. p. 112, 1941. ““? Strata penetrated by
well in San Diego.”

Nucula (Acila) castrensis Hinds, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 95, 1903. Cooper’s record (1888)
cited from San Diego well. — Reagan, Trans. Kansas
Acad. Sci., Vol. 22, p. 174, 1909. The record ‘San
Diego (Cooper). — Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 116, pl. 1, figs. 6a, 6b
(Recent), 1931. ‘?Miocene; Pliocene to Recent. Also
“San Diego well, San Diego (Cooper).”

Acila (Truncacila) castrensis Hinds, Schenck, Geol. Soc.
Amer., Spec. Papers No. 4, p. 96, pl. 10, figs. 1-5
(Recent), text fig. 7 (2-5), 1936. Pliocene to Recent.
From San Diego Pliocene at “loc. 331 [SD], ravine
200 feet north of Mexican boundary, 3/4 mile east of
coast,’ Pliocene.

Type specimen.
(according to Schenck).

Type locality. — “Hab. Sitka, North-west America.
A single specimen was dredged in the harbour, from seven
fathoms, sand.”’ (Hinds.)

Range. — Pliocene to Recent. Recent, Sitka, Alaska,
to Cedros Island, Lower California, Mexico, in 9 to 1280
meters ( 5 to 700 fathoms).

Occurrence in San Diego Fm. — Well at San Diego
(Dall). C.A.S. 12099, 28889, 28892. L.A.M. 104, 107,
305. S.D. 331. U.C. A-8333. U.C.L.A. 294, 295, 809,
312, 2359.

Original description. — Nuc. testa elliptica, antice
rotundata, epidermide olivacea induta; lineis divaricatis;
marginibus ventralibus crenulatis; cardine antice dentibus
5, postice 11. Long. 3; lat. 1 1/2; alt. 2 lin. (Hinds.)

Remarks. — Three specimens of this posteriorly
truncate species, one with both valves, and two single
valves, are present in the Henry Hemphill collection of the
California Academy of Sciences from the San Diego well.
The largest specimen, a single valve, is approximately 9 mm
long, 7.3 mm high, convexity, 2.4 mm. The shape and
sculpture of these specimens are similar to that of speci-
mens of comparable size now living in west American
waters.

Over a hundred specimens of this species were
collected by Kanakoff at Loc. 305 (LAM), near the
United States-Mexico boundary. The largest valve is 11 mm
long and 8.8 mm high. A cast from Loc. 104 (LAM), is
12.8 mm in length.

Schenck’s careful study (1936) of Acila castrensis
indicated that specimens occurring in the waters of
southern California attain maximum lengths of about
12 mm, but that those occurring in the waters of Washing-
ton and Alaska may attain a length of 20 mm, and a
height of 16 mm. He also mentioned that the anterior
series of teeth may range to 24 in number and the posterior
series to 12. The height in some specimens may range

— Present disposition unknown

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

from 74 to 90 per cent of the length. Frizzell (37)
published the results of a study of the variation in the
sculpture of 358 specimens from Puget Sound. The soft
parts of A. castrensis were studied by Heath (38).

Acila castrensis has been recorded from various
localities in California in beds of Pliocene and of Pleisto-
cene age. The records of its occurrence by Khomenko
(39) in strata of late Tertiary age on the Schmidt Penin-
sula, Kamtschatka, and that of Simonova (40) from east
Sakhalin, need confirmation.

FAMILY NUCULANIDAE H. AND A, ADAMS (41)

Shell similar to the Nuculidae but elongated, the
posterior side longer, narrower, often rostrate, and partly
gaping at the end; the anterior end shorter, more rounded
and convex; hinge and ligament as in the Nuculidae, the
resilium sometimes external or lacking; internal shell layer
subnacreous in the early forms but mostly porcelaneous
in more Recent forms; mantle lobes more or less united;
with siphons; pallial line usually sinuated. Devonian to
Recent.

Remarks. — Stenzel et al., 1957, placed this family
under a Superfamily ‘‘Nuculanicae”. McAllister, 1964,
also favors assigning a superfamily (“‘Nuculanicea”’) to this
group of mollusks.

Dell (42) cited about 90 names (some homonyms,
synonyms, or unacceptable for various reasons) which have
been proposed for supraspecific units of this family.
Verrill and Bush (43) published a revision of the Nucu-
lanidae of the Atlantic Coast of the United States.

Most of the Recent species of this family live on
muddy bottoms.

Key to Genera of Nuculanidae

A. Shell closed ( or nearly so) posteriorly;

pallial sinus usually shallow .Nuculana
B. Shell gaping posteriorly; se
sinus usually deep : . Yoldia

GENUS NUCULANA LINK

Nuculana Link, Beschreib. Nat. — Samml. Univ. Rostock,
Abt. 3, p. 155, May 17, 1807. Sole species: ‘‘N.
rostrata.”’ Ref. to Gmelin, p. 3308, and to Chemnitz,
Vol. 7, pl. 55, figs, 550, 551. — Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 118, 1931. “Type
(by monotypy) Arca rostrata Chemnitz.” — Hertlein
and Strong, Zoologica, Vol. 25, Pt. 4, p. 390, 1940.
“Type (by monotypy): Arca rostrata Chemnitz.” —
Cox, Mem. Geol. Surv. India, Palaeo. Indica, Ser. 9,
Vol. 3, Pt. 3, p. 26, 1940. “Genotype: Arca rostrata
Chemnitz.”

Leda Schumacher, Essai Nouv. Syst. Test., pp. 55, 172,
173, 1817. Type indicated as Arca rostrata Chemnitz,
illustrated by Schumacher on pl. 19, fig. 4.

Type species (by monotypy). — Arca rostrata
Chemnitz [= Mya pernula Miller]. [“Arca Martini
rostrata’”’ Chemnitz, Neues Syst. Conchyl. — Cab., Bd. 7,
p. 206, pl. 55, figs. 550, 551, 1784. “Sie werde schon
ohnweit Helsingburg in einen Meerbusen bey Kullen, und
noch haufiger bey Norwegischen Stranden gefunden.” —

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Schenck, Bull. Mus. Roy. d’Hist. Nat. Belgique, Vol. 10,
No. 20, pl. 1, fig. 2, 1934 (hinge of Nuculana pernula
Miller). — Habe, Gen. Jap. Shells, Pelecypoda, No. 1, p.
24,1951. Type species: Arca rostrata Bruguiere. (Figs.
20, 21, Nuculana pernula Miller). |

Range. — Jurassic (perhaps Triassic) to Recent.
Recent, world-wide, abundant in cool marine waters, 5
to 3658 meters (3 to 2000 fathoms).

Description. — Shell elongate, often somewhat
crescent-shaped, usually rostrate and somewhat carinate
posteriorly bounding an escutcheon; valves closed or
gaping slightly at the posterior end; beaks small,
opisthogyrate; sculpture consisting chiefly of concentric
threads, more closely spaced toward the ventral margin;
resilium on a small, triangular chondrophore, inclined
posteriorly under the beaks and separating two series of
teeth, the posterior series about twice as numerous as the
anterior series; this arrangement of the resilium is present
in Cenozoic forms but in some earlier groups it is nearly
lacking and the ligament is entirely posterior to the beaks;
pallial line sinuous in Recent forms but in some early
forms it is only slightly or not sinuated.

Remarks. — About 20 species of this genus have been
described from Tertiary strata in California and about 60
species have been recorded occurring in the marine waters
of the western Americas between Bering Sea and Cape
Horn. Only about four species have been recorded from
beds of Pliocene age in western United States, one of which
occurs in the San Diego formation.

Cox, 1940, discussed some of the Mesozoic Nuculana-
like forms. He pointed out that many Jurassic species are
referable to the genus Nuculana but that it is doubtful
whether they are referable to Recent subgenera. Some of
the Jurassic species possess nacreous shells and some
species have an entire, not sinuated pallial line.

SUBGENUS NUCULANA S. S.
Nuculana (Nuculana) aff. N. (N.) leonina Dall
Plate 57, Figures 17, 20

The following references refer to typical N. leonina.
Leda leonina Dall, Nautilus, Vol. 10, No. 1, p. 2, May,
1896. “Off Sea Lion Rock, Coast of Washington in
477-559 fathoms, mud, U. S. Fish Commission.” —
Dall, Bull. Nat. Hist. Soc. Brit. Columbia, No. 2, p. 7,
pl. 2, fig. 12, January, 1897. ‘dredged by the U. S.
Fish Commission in the Straits of Fuca and off Sea
Lion Rock on the coast of Washington, in 477-559
fathoms.” — I. S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 21, pl. 13, fig. 18, 1924. Type
locality cited. “Range. Strait of Juan de Fuca to
latitude 36 north.”
Occurrence in San Diego Fm. — L.A.M. 305A.
Remarks. — A right valve of a Nuculana, 8.6 mm
long and 4.8 mm high, is present in the collections from
near the Mexican boundary. The exterior sculpture is
comprised of ten narrow, elevated ridges between which
in some areas there are traces of minute concentric striae.
A narrow shallow depression just below the dorsal
posterior margin extends from near the beak to the
posterior end of the valve.
The present specimen bears a general resemblance to
Nuculana leonina Dall but is less rostrate, higher in

149

proportion to the length, has much wider interspaces
between the concentric ridges and fewer hinge teeth.

There is variation in the sculpture in a series of
specimens of N. leonina but none that we have seen have
nearly such wide interspaces between the concentric
ridges and all have many more teeth on the hinge.

The present fossil probably represents an undescribed
species, but because only one small valve which has under-
gone some erosion is available, we merely report its oc-
currence and call attention to its general similarity to
N. leonina.

SUBGENUS SACCELLA WOODRING

Ledina Sacco, Moll. Terr. Terz. Piemonte e Liguria, Pt. 26,
p.53, December, 1898. “‘(Tipo L. fragilis (Chemnitz))”.

Not Ledina Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 4, p. 580, April, 1898. “Type L. eborea Conr.,
1860, not 1846, = L. smirna Dall, Eocene.”

Saccella Woodring, Carnegie Inst. Washington, Publ. 366,
p. 15, May 20, 1925. “Type (by original designation).
— Arca fragilis Chemnitz (= Leda commutata Philippi).”
— Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ. 3,
p.53,1930. Type as indicated by Woodring. — Hertlein
and Strong, Zoologica, Vol. 25, Pt. 4, p. 392, 1940.
“Type (by original designation): Arca fragilis Chemnitz.”

Type species (by original designation). — Arca
fragilis Chemnitz [Neues Syst. Conchyl. -Cab., Bd. 7,
p. 199, pl. 55, fig. 546, 1784. “Mittellandischen Meeres.”
— Buequoy, Dautzenberg, and Dollfus, Moll. Mar.
Roussillon, Vol. 2, Fase. 5 (Pelecypoda, Fasc. 18), p. 215,
pl. 37, figs. 26-31, 1891 (= Nucula commutata Philippi).
Mediterranean and east Atlantic. Miocene to Recent].

Range. — Paleocene (Midway) to Recent (Gardner,
Bull. Amer. Assoc. Petrol. Geol., Vol. 25, No. 4, p. 647,
1941).

Description. — Shell small, high, slightly inequilateral,
posterior end rostrate, rostrum sharply pointed and
unicarinate; a shallow groove extends from the umbo to
the ventral margin at both ends of the valve; sculpture
consisting of strong concentric rugae; hinge like Leda s. s.,
but the anterior and posterior series of teeth are approxi-
mately equal in length; apex of pallial sinus broadly U-
shaped. (Woodring, 1925.)

Remarks. — The shell of Saccella differs from that of
Lembulus Risso (44) in that it has concentric instead of
diagonal sculpture and also it has a narrower and shallower
posterior groove.

Another genus, Jupiteria Bellardi (45), type Nucula
concava Bronn, has a hinge similar to that of Saccella but
the shape of the shell is more like that of Corbula and
the exterior bears very fine, regular, concentric sculpture.

Praesaccella Cox (46) described from beds of
Jurassic age in India is said to differ from Saccella in that
the pallial line lacks a sinus and the hinge teeth are larger
and less numerous.

Mesosaccella Chavan (47), described from strata of
late Cretaceous age in Europe, has an external ligament
situated just posterior to the beaks. The series of teeth
continue beneath the beaks where they are elevated. There
is no well defined ligamental pit, the fossette is merely a
vague triangular depression formed by an enlargement of
the cardinal margin.

Nuculana (Saccella) taphria Dall
Plate 27, Figures 11-13, 16-18

Nucula caelata Hinds, Proc. Zool. Soc. London, p. 99,
December, 1843. — Hinds, Zool. Voy. Sulphur, Moll.,
Pt. 3, p. 64, pl. 18, fig. 13, 1844 (January 1845 on
cover of Pt. 3).

Not Nucula coelata Conrad, Amer. Jour. Sci., Vol. 23,
No. 2, p. 343, January, 1833. Claiborne, Alabama.
London clay [Eocene].

Leda coelata Hinds, Dall, Proc. Calif. Acad. Sci., Vol. 5,
p. 297, December, 1874. ‘“‘well at San Diego.”
“Pliocene.” — Dall, Proc. U.S. Nat. Mus., Vol. 1, p. 11
(well at San Diego), p. 28 (‘‘well-digging in stratum
B2.”), 1878. — Hertlein and Grant, Mem. San Diego
Soe. Nat. Hist., Vol. 1, p. 48, 1944. Dall’s record
(1874) cited.

Leda caelata Hinds, Cooper, Calif. State Min. Bur., Seventh
Ann. Rept. State Mineral., Vol. 7, p. 245, 1888. “San
Diego well.” Pliocene. — Orcutt, West Amer. Sci.,
Vol. 6, Whole No. 46, p. 85, August, 1889. Dall’s
record (1874) cited. — Oreutt, cited by Ellis in Ellis and
Lee, U. S. G. S., Water Supply Paper 446, p. 59, 1919.
Orcutt’s citation of Dall’s record (1874).

Leda taphria Dall, Nautilus, Vol. 10, No. 6, p. 70,
October, 1896. New name for Nucula ‘“‘coelata” Hinds,
1843, not Nucula coelata Conrad, 1833. — Arnold,
Mem. Calif. Acad. Sci., Vol. 3, p. 98, pl. 17, fig. 5
(lower San Pedro Series), 1903. ‘‘San Diego well
(Cooper)” and “Pliocene of Pacific Beach”. — Arnold,
U. S. G. S., Prof. Paper 47, p. 28, 1906. “San Diego
formation.’’ — J. P. Smith, Proc. Calif. Acad. Sci., Ser.
4, Vol. 3, p. 172, 1912. “San Diego-Purisima.” —
Waterfall, Univ. Calif. Publ. Bull. Dept. Geol. Sci.,
Sci., Vol. 18, No. 3, table opp. p. 78, 1929. “San
Diego Pliocene’. Also other formations.

Nuculana taphria Dall, Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 121, pl. 1, fig. 8 (Holser
Canyon, Pliocene), fig. 9 (near Goleta, California,
Pleistocene), 1931. “San Diego formation of Reynard
Way, San Diego,” also record of Arnold (1906) and
Cooper (1888) cited.

Saccella taphria Dall, Moore, San Diego Soc. Nat. Hist.,
Occ. Paper 15, p. 50, pl. 23, figs. e, f, g, 1968. Balboa
Park; Pacific Beach, Pliocene. Also other localities.
Also Miocene to Recent.

Type specimen. — Location unknown to the present
authors. Originally in “‘Cab. Belcher.” Not found in
British Museum by Keen (Veliger, Vol. 8, No. 4, p. 267,
1966).

Type locality (of Nucula caelata). —“‘Hab. California,
between 38° 18’ and 34° 24' north latitude; namely, at
Russian Bodegas, San Francisco, and Santa Barbara, in
from six to ten fathoms.”

Range. — Late Miocene (Briones): Pliocene to
Recent. Recent from Bodega Bay, California, to Punta
Arena, Lower California, in 5 to 93 meters (3 to 51
fathoms).

Occurrence in San Diego Fm. — Well at San Diego
(Dall). C.A.S. 1400, 1401, 1402, 1404, 28889. L.A.M.
104, 107, 305, 305A, 305C, A1323. S.D. 29, 75, 80.
U.C. A-8333. U.C.L.A. 294, 1386, 2359.

Original description of Nucula caelata Hinds. — Nuc.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

testa luteo-virente, oblonga, argute sulcata; anticé arcuate
rostrata, sulcis paululim obliteratis; umbonibus prominulis.
Long. 7; lat. 3; alt. 4 lin. (Hinds.)

Remarks. — The description attributed to Dall by
I. S. Oldroyd, 1924, is from Arnold, 1903.

The umbos of Nuculana taphria are nearly centrally
situated, the rostrum is bluntly pointed and the exterior is
sculptured with well developed, uniform, sharp, raised,
concentric ribbing. A narrow lunular area is present and
there is a long, narrow escutcheon concentrically striated.
A narrow, shallow, depressed area extending from the
umbos to the ventral margin is usually present just
anterior to the dorsal margin. There are two gently
curved rows (the anterior slightly the longer) of chevron-
shaped teeth, about 20 in each series. A shallow pallial
sinus is present. A typical specimen from off San Martin
Island, Lower California, is 18 mm long, 11.2 mm high,
convexity (both valves together), 8.9 mm.

Heath (48) described the soft parts of this species.

We have examined over two hundred specimens,
ranging from 3 to 22.6 mm in length, collected by George
Kanakoff at Loc. 305 (LAM), near the Mexican boundary,
and find variation fully as great as in a similar series of
Recent shells. Larger shells tend to be more globose with
the posterior end more pointed and upturned. Some of
these have been bored on the umbo by a gastropod.

When Dall, 1896, proposed the new name, Leda
taphria for Nucula caelata Hinds (non Conrad), he gave no
description nor did he cite any type specimen.

Mrs. Ellen J. Moore, United States Geological
Survey, examined specimens in the United States National
Museum which were labelled Nuculana taphria by Dall,
and furnished us information concerning them which we
include here.

She stated (49) that a specimen, No. 122579
(USNM), 18 mm long, entered in the catalogue on July 25,
1891, was labelled by Dall “Leda taphria Dall, (Fig’d.),
Sta. 3147, 56 fms., mud, 49.2°, off Pt. Ano Nuevo, Cala.”
Another specimen, No. 107432 (USNM), 17.2 mm long,
entered in the catalogue April 13, 1896, was labelled
“Leda caelata Hinds, Fig’d., 56 fms., off Pt. Ano Nuevo,
Cala. USFC.” In the vial with the specimen there is a
printed slip by Dall, stating ‘‘Fig’d. type.” This specimen
compares favorably with the specimen illustrated by Dall
in 1897 which he stated was 17 mm long. Furthermore,
Mrs. Moore stated that neither of the specimens mentioned
above were entered as types in the catalogue and both
were in the general collection of mollusks.

It appears to us that Dall originally made a simple
substitution of the name taphria for caelata Hinds and
Dr. H. A. Rehder (50), United States National Museum,
concurs in this opinion. We, therefore, consider the
specimen illustrated as Nucula caelata by Hinds to be the
type of Nuculana taphria.

The original figure by Hinds is 13 mm long. Com-
pared with this the specimen illustrated by Dall, 1897, is
more globose, slightly higher in proportion to the length
and it is posteriorly slightly more concave and pointed.
Through the courtesy of Dr. Harald Rehder, we were able
to examine this specimen illustrated by Dall. The
dimensions are approximately, length, 17.2 mm, height,
11.4 mm, convexity (both valves together), 9.2 mm. In
view of the variation in this species, we are inclined to
consider both illustrations as representing the same species.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

The shell of this species is less elongate, more in-
flated, and the surface is less polished than that of
Nuculana callimene Dall (51) from Panama and _ it
has much coarser sculpture than that of N. pontonia Dall
(52), originally described from the Galapagos Islands.
The presence of an anterior lunular area on N. taphria
serves to separate it from the similar N. balboae Brown
and Pilsbry (53) from mid-Miocene strata of Panama.
Furthermore, the Panamanian species has a much greater
number of teeth, 28 in the anterior and 18 in the posterior
series.

A species recently described as Saccella calkinsi by
Moore (54) from the Astoria formation of middle
Miocene age in Oregon, is said to differ from N. (S.)
taphria in the less strongly recurved rostrum, narrower,
longer escutcheon and narrower and less ovate lunule.

Nuculana taphria has been reported by some
authors (55) as definitely identified from strata of late
Miocene age but others (56) have cited it with doubt as
“Leda cf. taphria Dall” from beds of similar age.
Records of its occurrence in the later Tertiary of
Kamtschatka (57) and in Sakhalin (58) may be open to
question.

GENUS YOLDIA MOLLER

Yoldia Moller, Naturhist. Tidsskrift, Bd. 4, No. 1, p. 91
(also separately, Index Moll. Groenlandiae, p. 18),
1842. Species cited: “‘Y. arctica, Nucula arctica Gray”
and ‘“Y. angularis nob., Nuc. myalis Couth.?” —
Verrill and Bush, Proc. U. S. Nat. Mus., Vol. 20, No.
1139, p. 858, June, 1898. “Type. — Yoldia hyperborea
Torrell = Yoldia arctica Moller (not Gray).”’ — Stewart,
Acad. Nat. Sci. Philadelphia, Spec. Publ. No. 3, p. 59,
1930. Type designation of Verrill and Bush accepted.
— Kanno, Jap. Soc. Promotion of Sci., Neno, Tokyo,
p. 198, 1960. Type: Nucula arctica Moller.

Type species (designated by Verrill and Bush, 1898.
Also by the Internatl. Comm. Zool. Nomencl., Opinion
769, Bull. Zool. Nomencl., Vol. 23, Pt. 1, p. 33, April 29,
1966). — “the nominal species Yoldia hyperborea Torell,
1859, is hereby designated to be the type-species of that
genus.” [Yoldia hyperborea Torell, Bidrag till Spitz-
bergens molluskfauna (Stockholm), pp. 149-150, tab. 2,
figs, 6a, 6b, 1859. — Ockelmann, Medd. om Grénland,
Bd. 107, No. 7, pl. 1, fig. 1; pl. 2, fig. 3, 1954. — Cowan,
Veliger, Vol. 11, No. 1, p. 58, pl. 5, figs. 6 (Point Barrow,
Alaska), 7 (Disco, Greenland), 1968. |

Range. — Late Cretaceous to Recent. Recent
chiefly in boreal and temperate waters, 0 to 5303 meters
(0 to 2900 fathoms).

Description. — Somewhat similar to Nuculana but
with thinner, subovate shell, slightly rostrate, usually
gaping posteriorly; exteriorly sculptured by growth lines on
concentric striae; hinge consisting of two subequal series of
small chevron-shaped teeth; resilium-pit large, sym-
metrically underlapping both rows of teeth; pallial sinus
deep and wide, the apex broadly U-shaped. (Hertlein and
Strong.)

Remarks. — The species of Yoldia are most abundant
in boreal waters. In western North America 21 species
have been reported living in waters between Bering Sea
and San Diego, California, and about a dozen species have
been reported in the region between Cedros Island, Lower

151

California, Mexico, to southern Chile. Fourteen species
have been reported from strata of Tertiary age in California,
five of them in strata of Pliocene age in California and two
in Oregon. The genus is here reported from the San Diego
Formation for the first time.

Uozumi (59) discussed many of the Japanese fossil
forms of Yoldia and Ocklemann (60) remarked on the
relationships of various North Atlantic species of this
genus.

SUBGENUS KALA YOLDIA GRANT AND GALE

Kalayoldia Grant and Gale, new section, Mem. San Diego

Soc. Nat. Hist., Vol. 1, p. 128, November 3, 1931.

Type species (by original designation). — Yoldia
cooperii Gabb.

Range. — Oligocene (Eugene formation), to Recent.

Original Description. — Like Yoldia, s. s., but poster-
ior dorsal margin of shell curved, concave upward, typically
much shorter than anterior dorsal margin; posterior portion
of valves rostrate, typically somewhat narrowed vertically;
sculpture consisting of definite concentric riblets; hinge
with a long, gently curved anterior row of teeth, separated
by a relatively large, shallow, ovate ligamental pit from
the very short, nearly straight posterior row of teeth;
pallial sinus large and deep. (Grant and Gale.)

Remarks. — Six or seven species described from the
late Cenozoic of western North America are referable to
this subgenus. The single Recent species, the type species
of this group, ranges from central California to northern
Lower California, Mexico.

Yoldia (Kalayoldia) cf. Y. (K.) cooperii Gabb

The following references, type specimen, type
locality, range and description, refer to typical Y. cooperii.
Yoldia cooperii Gabb, Proc. Calif. Acad. Nat. Sci., Vol. 3,

p. 189, January, 1865. — Gabb, Geol. Surv. Calif.,
Palaeo., Vol. 2, p. 31 (in part), pl. 9, fig. 54 (as Y.
cooperi), 1866. “picked up by Dr. Cooper on the
beach at Santa Cruz.’’ — Schenck and Keen, California
Fossils for the Field Geologist (Stanford Univ.: Calif.),
1940, pp. 65, 69, 80 (pp. 67, 71, 82, ed. 1950), pl.
1, fig. 3; pl. 4, fig. 12. Halfmoon Bay, California,
Recent.

Yoldia cooperi Gabb, Packard, Univ. Publ. Zool., Vol. 14,
No. 2, p. 248, pl. 14, fig. 9, 1918. ‘“‘dredged alive out-
side the Golden Gate, in 68 fathoms and on a bottom
composed of dark green sand.” — I. S. Oldroyd, Stand-
ford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 30, pl.
1, fig. 1; pl. 37, fig. 9, 1924. San Francisco Bay to
San Diego, California. — Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 128, pl. 1, fig. 13;
pl. 14, fig. 3, 1931. Halfmoon Bay, California, Recent.
Also cited from late Miocene to Recent. — Moore,
San Diego Soc. Nat. Hist., Occas. Paper 15, p. 68, pl.
32, figs. d,e, 1968. San Diego area, Pleistocene.

Not Yoldia cooperii Gabb, Geol. Surv. Calif., Palaeo., Vol.
2, p. 31 (in part), 1866. “Miocene, south of Martinez,
and north of Walnut Creek, Contra Costa County.”
Referred to Yoldia cooperii supramontereyensis Arnold,
by Stewart, Acad. Nat. Sci. Philadelphia, Spec. Paper No.
3, p. 63, pl. 15, fig. 2, 1930.

Type specimen. — No. 30, 613, Univ. of California

152

Department of Paleontology, Invertebrate Type Collection.

Type locality. — ‘‘A single left valve was found on
the beach at Santa Cruz, Cal., by Dr. Cooper.”

Range. — Middle Miocene (“‘cf.””) to Recent. Recent
from off Point Reyes, California, to Todos Santos Bay,
Lower California, Mexico, in 9 to 124 meters (5 to 68
fathoms), usually in sand.

Occurrence in San Diego Fm. — L.A.M. 323.

Original description: Shell thin, somewhat com-
pressed, very inequilateral, beaks placed about a third of
the length from the anterior end, minute; anterior end
narrow, sub-acuminate, posterior end broadly rounded;
base most prominent just posterior to the middle of the
shell; surface sculptured by numerous small concentric
ribs, rarely dichotomous or anastomosing on the widest
part of the shell; these ribs are flat and abruptly truncated
on the side nearest the beak, giving the surface, under a
glass, the appearance of an overlapping. Epidermis
shining, olivaceous; internally a bluish white; muscular
scars large, the anterior triangular, posterior a third the
largest, broadly suboval. Long. 1.25, lat. 2.6, alt. .25
[inches]. (Gabb.) [A description also was given in the
Latin language. ]

Remarks. — Fragments of two fossil valves retaining
the umbonal area, ligamental pit and several teeth, are
present in the collection. The largest fragment is 4.8
mm long. These fragments agree well with the cor-
responding portions of the shell of Yoldia cooperi .

The large ligamental pit and hinge teeth evidently
are part of large valves. The largest Recent specimen, a
right valve, in the collections of the California Academy
of Sciences, collected by Henry Hemphill at San Diego,
is 52.6 mm long and 25.5 mm high. A large left valve
from Loc. 92 (CAS), collected by Bruce Martin from beds
of late Pleistocene age on Deadman Island, San Pedro,
California, is 55 mm long and 28 mm high.

Compared to Yoldia oregonensis Conrad (62),
described from strata believed to be of Oligocene age, the
beaks of Y. cooperii are more posteriorly situated and the
rostrum is shorter.

Yoldia supramontereyensis Arnold (63), described
from beds of late Miocene age in California, is less at-
tenuated posteriorly than typical Y. cooperii.

Yoldia cooperii tenuissima Clark (64), described
from beds of late Oligocene or early Miocene age in
central California, has the beak more anteriorly situated
and a longer rostrum than Y. cooperii.

A fossil form described as Yoldia cooperi ochotensis
Khomenko (65), from beds of Pliocene age on Sakhalin
Island in the North Pacific, is referable to the subgenus
Cnestrium Dall. Illustrations of it reveal the presence of
oblique lines crossing the concentric sculpture. It
obviously is not related to Y. cooperii. Kamada (66)
pointed out that this also was true of specimens referred
to Y. c. ochotensis by Otuka (67).

Another fossil form, “Yoldia cooperi Gabb var.
kovatschensis” Slodkewitsch (68), was described from
beds questionably of Oligocene age on Kamtschatka. The
concentric sculpture was described as consisting only of
fine concentric lines but lacking concentric ridges such as
are present on Y. cooperii.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

SUBCLASS PTERIOMOPHIA BEURLEN

ORDER EUTAXODONTIDA GROBBEN

SUPERFAMILY ARCACEA OKEN (69)
FAMILY ARCIDAE OKEN (70)

Shell equivalve, or nearly so, trapezoidal, sub-
quadrate, or rounded, with the posterior side equal or
longer; ligament exterior, attached to an area beneath and
often on both sides of the beak; hinge with taxodont
teeth in two similar series meeting below the beaks, the
long dimension of the individual comb-like teeth approxi-
mately at right angles to the dorsal margin of the valves;
pallial line generally distinct, without a sinus; muscle im-
pressions nearly equal. (Grant and Gale, 1931). Middle
Jurassic (71) to Recent. Recent, world-wide.

Abundant in shallow, tropic, subtropic and warm
temperate marine waters, but two genera, Senila Gray and
Scaphula Benson, occur in brackish water, the latter also
occurs in fresh water. Bathyarca occurs at depths of
3658 meters (2000 fathoms).

Remarks. — Reinhart (72) published a very useful
monograph of the fossil west American species of this
family. The Recent species have been discussed by Maury
(73) and by Hertlein and Strong (74), and a publication
by Olsson (75) contains a discussion of the members of
the Arcidae living in the tropical waters of Peru and
Ecuador. A recent paper by Noda deals with the Cenozoic
Arcidae of Japan (Sci. Repts. Tohoku Univ., Sendai,
Second Ser. (Geol.), Vol. 38, No. 1, pp. 1-130, pls. 1-14,
figs. 1-16 in text, October 10, 1966). The anatomy of
the Arcidae is discussed in a paper by Heath (76).

Eleven species and subspecies of the Arcidae were
recorded by Reinhart from strata of Pliocene age in
California. Four species and subspecies occur in the San
Diego Formation.

Key to Genera and Subgenera of Arcidae

A. Ligamental area extremely wide and
almost flat . Arca
B. Ligamental area narrow and V-shaped

a. Inner margin strongly crenulated;
ribs narrow, strap-like
aa. Inner margin not crenulated or
only faintly so; ribs thread-like,
usually alternating in size

. Anadara

b. Ligamental grooves all extending
anterior to the beak; hinge with a
continuous series of teeth .

bb. Ligamental grooves confined
chiefly posterior to the beak;
hinge of adult with an edentulous
gape centrally .

. Barbatia

. Fugleria
GENUS ARCA LINNAEUS

Arca Linnaeus, Syst. Nat., ed. 10, p. 693, 1758. Fifteen
species cited including Arca noae. — Reinhart, Bull.
Mus. Roy. d’Hist. Nat. Belgique, Tome 11, No. 13, p.
14, 1935. “Type species; Arca noae Linne.... . H

Navicula Blainville, Dict. Sci. Nat., Vol. 34, p. 319, 1825.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Type (by monotypy): Arca noae Linnaeus. — Iredale,
Brit. Mus. (Nat. Hist.), Great Barrier Reef Exped.
1928-29. Sci. Repts., Vol. 5, No. 6, Moll. Pt. 1, p.
291, 1939. “Haplotype: Arca noae Linné.”’

Not Navicula Bory de Saint-Vincent, Dict. Class. Hist. Nat.
Paris, Vol. 2, p. 128, 1822. [Diatomacea.]

Byssoarca Swainson, Zool. Mlustr., Ser. 2, Vol. 3, expl. to
pl. 118, 1832-1833, issued March, 1833. Species cited:
“Byssoarca zebra” from the “West Indies’ and

“Jamaica’’, and “‘B. noae.’’— Sowerby, Proc. Zool. Soc.

London for 1833, p. 16, issued May 17, 1833. —
Herrmannsen, Ind. Gen. Malacozoor, Vol. 1, p. 149,
1846. “‘Typus: Arca Noae Linn.”

Type species (by designation of Internatl. Comm.
Zool. Nomencl., Opinion 189, signed October 5, 1944,
published July 26, 1945). — Arca noae Linnaeus, 1758
[Syst. Nat., ed. 10, p. 693, 1758. ‘‘Habitat in M. rubro,
Mediterraneo, Indico.”’ Ref. to “List. conch. 3. B.s.6.c.1.
t.5.”; “Rumph. mus. t. 44.f.P.”; “Gault. test. t.87.f.H.1.”,
and others. Illustrated by Bucquoy, Dautzenberg, and
Dollfus, Moll. Mar. Roussillon, Tome 2, Fase. 5 (Pele-
cypoda, Fasc. 18), p. 174, pl. 30, figs. 1-5, (6, var.), 1891.
Mediterranean region, Atlantic to Senegal and the Canary
Islands. For a discussion of this species see Dodge, Bull.
Amer. Mus. Nat. Hist., Vol. 100, Art. 1, pp. 143-144
1952].

Range. — Middle Jurassic to Recent. Reported from
Eocene to Recent in western North America. Recent,
worldwide in tropical and subtropical marine waters, but
some species ranging into the boreal zone. Mostly in
intertidal zone to shallow neritic zone, occasionally to a
depth of 146 meters (80 fathoms) or deeper. Arca
tetragona Poli reported from a depth of 2655 meters
(1457 fathoms).

Description. — The Arcas typified by A. noae are
equivalve, inequilateral transversely elongate, rudely quad-
rate, or oval, commonly irregular in outline, and gaping
anteriorly. The beaks are prominent, placed well forward
and separated by a wide cardinal area scarred with oblique
discontinuous cartilage grooves. The radials that adorn
the outer surface differ in prominence and spacing on
different parts of the shell. The hinge is straight; the teeth
are numerous, short, subequal, and transverse. The
adductor impressions are distinct, the pallial line is simple,
and the inner margins are smooth or feebly crenate at the
extreme edge in harmony with the radial ornamentation
of the exterior. (Gardner, U. S. G. S., Prof. Paper 199,
p. 22, 1948.)

Remarks: Arca s. s. is here recorded for the first
time from the San Diego formation.

Reinhart cited seven species from the Cenozoic of
western North America. Three species now live in
tropical and subtropical waters of the western Americas.
One of these, A. fernandezensis Hertlein and Strong, was
originally described from Juan Fernandez Island off Chile
in 34° South Latitude. Arca pacifica Sowerby ranges
north to the head of the Gulf of California and to Scam-
mon Lagoon, 27° 54' North Latitude, on the Pacific
Coast of Lower California. In the Japan Sea, one species
of Arca s. s. ranges to 45° North Latitude.

>

SUBGENUS ARCA S. S.

153

Arca (Arca) sisquocensis Reinhart
Plate 27, Figures 26, 27, 31-33

Arca (Arca) sisquocensis Reinhart, Jour. Paleo., Vol. 11,
No. 3, p. 182, pl. 28, figs. 1-3, April, 1937. — Reinhart,
Geol. Soc. Amer., Spec. Papers No. 47, p. 25, pl. 2,
figs. (holotype), 10, 11, 12, 1943. ‘From the Care-
aga formation, Pliocene, of Fugler Point, near Santa
Maria, Calif.” — Hall, Jour. Paleo., Vol. 38, No. 1, p.
88 (in text), pl. 22, figs. 1 and 2, 1964. “Santa
Barbara Formation, Packards Hill, Santa Barbara,
California. _ Plio-Pleistocene.”

Arca sisquocensis Reinhart, Vedder, in Vedder and Norris,
U.S. G. S., Prof. Paper 369, p. 46, 1963. Terrace on
San Nicolas Island, “Pleistocene. — Valentine and
Lipps, Jour. Paleo., Vol. 37, No. 6, pp. 1294, 1299,
1963. 250-foot terrace on central Anacapa Island,
“Early Pleistocene (or late Pliocene) age”’.

Type specimen. — No. 1382, California Institute of
Technology.

Type locality. — “Pliocene asphalt beds of Fugler
Point, 7 1/2 miles southeast of Santa Maria, Santa Barbara
County, California (type).’”” [Cebada member of the
Careaga Formation (Woodring, 1950). |

Range. — Middle Pliocene to early Pleistocene.

Occurrence in San Diego Fm. — L.A.M. 305, 305A.

Original description (of holotype). — Small, well-
preserved right valve, elongate in outline, moderately in-
flated, slightly inequilateral.

Profile. — Anterior margin evenly rounded; ventral
margin straight, nearly parallel to hinge margin; posterior
margin straight, forming acute angle where it intersects
ventral margin, and meeting hinge margin at angle of 45°.
Umbo located just anterior to center of shell, projecting
slightly. An unusually sharp ridge extends from umbo to
posterior ventral corner; above this ridge, shell is con-
cave. A faint medial sulcus extends from byssal gape,
upward a short distance toward umbo.

Sculpture. — About 40 radial ribs, with occasional
small inter-ribs. On posterior slope, ribs are large and
dichotomizing; elsewhere, simple and ornamented with
closely-spaced nodes. The five anterior-most ribs are as
large as the posterior ones, but do not dichotomize. Con-
centric growth-lines are not prominent, but two distinct
concentric bands may be distinguished, and several less
distinct ones. Ligamental area narrow in front of umbo,
wide behind, these becoming noticeably excavated. About
two right-angled, chevron-shaped grooves directly beneath
umbo. Hinge straight, narrow, only slightly wider at ex-
tremities than at center; thirty-two teeth, small and
granular at center, increasing regularly in size toward ex-
tremities of hinge; teeth converge ventrally, the anterior
more sharply than the posterior. Muscle scars distinct,
notable because of a raised flange bordering inner side
of each scar, the posterior flange being the larger. (Such
raised flanges are ordinarily not present on Arca s. s., al-
though they are present in Striarca, and in Noetia and
Trigonarca a flange is developed on the inner side of the
posterior muscle scar; these flanges are therefore of
interest, and have been previously mentioned) (5)
[footnote]. Inner margin of shell crenulated, especially
at extremities. Narrow byssal gape near center. Pallial
line simple; within this line, inner side of shell faintly
striated by radial lines.

154

Dimensions of holotype (in mm): Length 15.4;
height 7.6; convexity (right valve) 4. (Reinhart.)

Remarks. — 20 specimens of this species vary in
preservation, and in size from 5 to 24 mm long. The
notable difference observed in this series, which varies
from Reinhart’s description of the type specimen, is the
presence of about seven ligamental grooves on the cardinal
area of the largest specimen (a fragment which represents
an individual probably 30 mm long). This larger number
of grooves is, no doubt, a result of the greater size of
this shell in comparison to the holotype which is 15.4
mm long.

Woodring (77) pointed out that ‘“‘Adult shells of A.
sisquocensis have a wider posterior slope than that of A.
kobeltiana, the posterior ridge being more strongly
curved.” An earlier name for Arca kobeltiana Pilsbry
(78) is A. boucardi Jousseaume (79), a species reported to
range from early Miocene to Recent in Japan.

Arca (Arca) leptogrammica Hall (80), described
from strata of late Miocene age in the Nipomo quadrangle,
San Luis Obispo Co., California, was compared by its
author with A. sisquocensis and A. boucardi. The type of
A. leptogrammica is 56 mm long. It was described as
much larger than A. sisquocensis and with finer radial
ribs which are not beaded.

GENUS ANADARA GRAY

Anadara Gray, Proc. Zool. Soc. London for 1847, p. 198
(issued November, 1847). “‘Arca antiquata” indicated
as type. — Cox, Rept. Palaeo. Zanzibar Protectorate,
p. 34, September, 1927. “Type: —A. antiquata
(Linne); original designation.”

Diluvarca Woodring, Carnegie Inst. Washington, Publ.
366, p. 40, May 20, 1925. “Type. — Arca diluvii
Lamarck.’ — Woodring, Carnegie Inst. Washington,
Publ. 385, p. 18, footnote, 1928. “‘Diluvarca is su-
pressed as a synonym of Anadara.”

Type species (by original designation): Arca
antiquata Linnaeus [Syst. Nat., ed. 10, p. 694, 1758.
“Habitat in O. Americano.” Illustrated by Hanley, Ipsa
Linnaei Conchylia, pl. 4, fig. 3, 1855, and by Woodring,
Carnegie Inst. Washington, Publ. 366, pl. 4, figs. 1, 2, 1925.
See discussion by Dodge (Bull. Amer. Mus. Nat. Hist.,
Vol. 100, Art, 1, p. 149, 1952) who considers Reeve’s
figure of Arca maculosa (Conch. Icon., Vol. 2, Arca, sp.
24, pl. 4, fig. 24, 1844) to represent the true A. antiquata
of Linnaeus |.

Range. — ?Late Oligocene (81) to Recent. Recent
in western North America from Cedros Island, Lower
California, Mexico, to the Gulf of California and south to
Paita, Peru, littoral zone to 128 meters (70 fathoms), but
usually in less than 75 meters (41 fathoms).

Description. — Shell thick, equivalve, ovate or
trapezoidal, gibbous, more or less inequilateral; valves
closed along ventral margin; cardinal area of moderate
width, with the greater part of its surface covered by the
ligament, and usually, although not invariably, ornamented
with a few chevron-shaped grooves; sculpture consisting
of strong, narrow, flattened ribs separated by squarely-
channelled interspaces; internal margins crenulated ac-
cording to the external ribbing; hinge-teeth obscurely dis-
continuous just behind the umbones, those belonging to
the anterior series being slightly longer than those of the

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

posterior series where the two series meet; central teeth
small, perpendicular to the hinge-margin, the teeth in-
creasing in length laterally and becoming slightly oblique
at each extremity. (Cox, 1927.)

Remarks. — Anadara has been confused with Arca
by some workers, but definite designation of Arca noae
Linnaeus as the type species of Arca clearly places
Anadara in a different group.

Diluvarca described by Woodring was later sup-
pressed by its author and considered to be referable to
Anadara. Olsson (1961, p. 87), more recently, doubted
that Anadara s. s. is represented in west American waters.
He assigned six species living in the eastern Pacific to
Diluvarca which he placed as a subgenus of Anadara.

Nineteen species and subspecies originally described
from the late Cenozoic of western North America were
referred to Anadara by Reinhart. A huge specimen 90 mm
long was reported by Mandra (82) from strata of late
Cenozoic age in Salinas Valley, California.

Four species of Anadara are known from strata of
Pliocene age in California. One species and a subspecies
occur in the San Diego Formation.

Iwasaki (83) recently discussed the species of
Anadara of Tertiary age in Japan.

Key to Species of Anadara (84)

A. Viewed from above (both valves together),

anterior end broadly rounded . . calcarea
B. Viewed from above (both valves together),
anterior end sharply pointed . trilineata

Anadara trilineata Conrad
Plate 28, Figures 1, 2, 3, 4, 6

Arca trilineata Conrad, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 8, No. 6, p. 314, dated December, 1856, but ap-
parently issued subsequent to April 25, 1857. — Con-
rad, U. S. Pac. Railroad Expl., Vol. 6, Pt. 2, No. 2,
p. 70, pl. 2, fig. 9, 1857. [Original reference and
locality cited.] “Tertiary.” Mlustration reproduced by
Slodkewitsch, Paleo. of USSR, Vol. 10, Pt. 3, Fase. 19,
Tertiary Pelecypoda from the Far East, Pt. 2, Acad.
Sci. USSR Press (Moscow; Leningrad), pl. 11, fig. 5,
see pp. 105, 214, 1938. — Arnold, U. S. G. S., Prof.
Paper 47, p. 100, 1906. ‘‘Pacific Beach, near San
Diego.” — J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4,
Vol. 3, p. 170, 1912. ‘San Diego-Purisima.” — J. P.
Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, p.
150, 1919. ‘San Diego.” — “ef.” Dall, cited by Ellis
in Ellis and Lee, U. S. G. S., Water Supply Paper 446,
p. 62, 1919. “lower member of . . . section” in well
in “South Las Choyas Valley.”> — Carson, Pan-Amer.
Geol., Vol. 43, No. 4, p. 268, 1925. “San Diego
fauna.’’ — Hertlein and Grant, Calif. State Jour. Mines
Geol., Rept. State Mineral., 35, p. 69, 1939. “higher
beds” in section of Pliocene strata at Pacific Beach. —
Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, p. 48, 1944. Refers to Dall’s record
(1874) of Arca microdonta from well at San Diego. —
Hertlein and Grant, Calif. State Div. Mines, Bull. 170,
chapter 2, p. 60, 1955. “San Diego formation.”

Arca microdonta Conrad, Dall, Proc. Calif. Acad. Sci.,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Vol. 5, p. 297, 1874. “well at San Diego.” “Pliocene.”
— Dall, Proc. U.S. Nat. Mus., Vol. 1, pp. 11, 28, 1878.
“Well” at San Diego and “‘well-digging in stratum B2.” —
Cooper, California State Min. Bur. Seventh Ann. Rept.
State Mineral., Vol. 7, p. 229, 1888. “San Diego
well.”” — Orcutt, West Amer. Sci., Vol. 6, whole No.
46, p. 85, 1889. Dall’s record (1874) cited. — Orcutt,
cited by Ellis in Ellis and Lee, U. S. G. S., Water Sup-
ply Paper 446, p. 59, 1919. Dall’s record (1874)
cited. — Hertlein and Grant, Mem. San Diego Soc. Nat.
Hist., Vol. 2, Pt. 1, p. 48, 1944. Dall’s record (1874)
referred to Arca trilineata.

Not Arca microdonta Conrad, House Doc. 129, Pro-
jected Vol. 3, 33rd Congress, 1st session, p. 13, 1855.
“Locality. — Tulare Valley ? Miocene.”

Arca sulcicosta Gabb, Geol. Surv. Calif., Palaeo., Vol. 2,
p. 31, pl. 9, figs. 53, 53a, 1866. ‘Found with
Dosinia Staleyi, on Mark West Creek, Sonoma County,
by Mr. V.S. Staley.” [ Pliocene. ]

Not Arca sulcicosta Nyst, 1836.

Arca schizotoma Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 4, p. 659, April, 1898. New name for Arca
sulcicosta Gabb, 1866. Not Arca sulcicosta Nyst,
1836. — Dall, U.S. G. S., Prof. Paper 59, p. 111, 1909.
“San Diego well.” — J. P. Smith, Proc. Calif. Acad.
Sei., Ser. 4, Vol. 3, p. 170, 1912. “San Diego-Purisima.”

Arca (Scapharca) trilineata Conrad, Dall, U. S. G. S., Prof.
Paper No. 59, pp. 110-111, 1909. “Pliocene of San
Diego well (city park), H. Hemphill, U. S. Nat. Mus.
7934; also Homer Hamlin.”

Arca (Arca) trilineata Conrad, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 139, pl. 2, fig. 1
(Shuman’s Cut), fig. 4 (Elsmere Canyon), 1931. P. 140,
“Pliocene of San Diego well (Hemphill and Hamlin,
fide Dall, 1909).”

Arca (Anadara) trilineata Conrad, Hertlein and Grant,
Calif. State Div. Mines, Calif. Jour. Min. Geol., Rept. 35
Calif. State Mineral., p. 70, 1939. “San Diego well.” —
Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, p. 57, 1944. ‘Pliocene strata at Pacific
Beach.”” — Glibert and Van de Poel, Mém. Inst. Roy.
Sci. Nat. Belgique, Deuxieme Sér., Fase. 77, p. 55, 1965.
Reynard Way, San Diego, Pliocene (as Anadara (s. s.)
trilineata).

Anadara trilineata Conrad, Woodring, Stewart, and
Richards, U.S. G.S., Prof. Paper 195, table opp. p. 112,
1941. “Strata at Pacific Beach.” — Vedder, U.S. G. S.,
Prof. Paper 400-B, p. B327, 1960. San Diego Forma-
tion at Pacific Beach. Also Niguel Formation and
others.— Milow and Ennis, 57th Ann. Mtg. Cordilleran
Sec., Geol. Soc. Amer., Field Trip Guidebook, San
Diego Co., p. 28, 1961. ‘San Diego formation”’.

Anadara (Anadara) trilineata subsp. trilineata Conrad,
Reinhart, Geol. Soc. Amer., Spec. Papers No. 47,
P= Ov pl: oy tig 9s" pl. 65 figs: 3; 5, 7 pl. 7, fig: 1,
1943. P.59, “Pliocene, San Diego well, Balboa Park,
San Diego.”

Anadara (Anadara) trilineata Conrad, Moore, San Diego
Soc. Nat. Hist., Occas. Paper 15, p. 36, pl. 16, figs. a,
b, 1968. Reynard Way, San Diego, Pliocene. Also
Pliocene of California, Oregon, and Washington.

Type specimen. — Location unknown to the present
authors. No record of the holotype at the U. S. National

Museum (see Reinhart, p. 58).

155

Type locality. — “Occurs with the preceding”
{which refers to Arca canalis Conrad with the locality
“Santa Barbara, Cal.” “Middle Tertiary.’ |.

Range: Late Miocene (Cierbo sandstone); early
and middle Pliocene in California, Oregon and Washington.

Occurrence in San Diego Fm. — C.A.S. 1129, 1401,
1404, 1415, 1418, 12107, 28885, 28889, 28892, 28893,
36384. L.A.M. 104, 107, 302, 305, 305A, 305B. S.D.
29, 34, 38, 79, 80, 81, 331, 365, 416, 417, 2954. U.C.
A-8333. U.C.L.A. 294, 295, 302, 310, 312, 2359.

Original description. — Trapezoidal, somewhat pro-
duced, inequilateral, ventricose; ribs 22-24, scarcely
prominent, square, wider than the intervening spaces,
ornamented with three impressed or four raised lines;
disks concentrically wrinkled; summits prominent; beaks
approximate. Length 3 inches. (Conrad.)

Remarks. — There is uncertainty concerning the
locality from which the type of Arca trilineata Conrad
originally came, and the whereabouts of the type specimen
is unknown. It is generally accepted that this is the well
known elongately subtrapezoidal species which occurs
as a fossil in strata of Pliocene age in California. Wood-
ring (85) gave an adequate discussion of the problem of
the type locality and the identification of this species.

We have had a large number of specimens available
for study including several hundred valves varying in length
from 5 mm to 68 mm, which were collected by G. P.
Kanakoff at Locs. 305 and 305A (LAM) near the Mexican
Boundary. The umbos of many of the valves have been
bored by a gastropod. A valve from Loc. 305B (LAM) is
79 mm long.

These specimens vary somewhat in proportion of
length to height but all are decidedly longer than high.
The number of ribs varies, usually from 25 to 28. This is
in agreement with Addicott’s observations on specimens
of this species from the Merced formation in northern
Santa Clara County, California. He stated (86) that most
of those have 26, some with 24, and some with 28 ribs.
The ribs on the anterior half of the shell are often deeply
suleated or almost bifid, those on the posterior half
usually bear two, three, or occasionally four shallow
grooves. The ribs usually begin to develop a medial
suleation after the shell attains a height of about 8 to
10 mm, occasionally earlier. The ribs are usually at least
partially beaded.

An impression of the anterior end of a large
Anadara, 73 mm long, collected by G. P. Kanakoff at Loc.
107 (LAM), end of Arroyo Drive in San Diego, is probably
referable to A. trilineata. The end view from above is not
broadly rounded as is that of A. ¢t. calcarea.

Specimens from the San Diego well in the collections
of the California Academy of Sciences labelled ‘Arca
microdonta Conrad” by Henry Hemphill, are definitely
referable to A. trilineata and A. trilineata calcarea.
Possibly the unfigured fossils recorded by Whiteaves
(87) under the name of Arca microdonta from beds of
late Tertiary age on Graham Island, Queen Charlotte
Islands, Canada, is referable to A. trilineata. Woodring
(88) and Reinhart (1943, pp. 46-47, p. 6, figs. 9, 10)
have given good discussions of Arca microdonta Conrad
(89), a species originally reported to have been found in
“Tulare Valley?.”” Blake who sent the fossil to Conrad
cited the locality as ‘“‘the hills of the Coast Mountains near
the Tulares.”” Woodring (1938, p. 31; 1941, p. 89) sug-

156

gested that this description might be applied to Kettleman
Hills but he believed it possible that the specimens were
collected by Blake on the Atlantic coast of Panama. The
type specimen, of which we have seen a cast, bears a close
resemblance to A. nobilis Roding in Bolten (A. deshayesii
Hanley), a Recent Floridan and West Indian species. More
recently, Weaver (90) cited “Anadara? microdonta (Con-
rad)” from the Temblor Formation, middle Miocene,
Santa Monica, California. The illustrations closely
resemble those of Anadara topangensis Reinhart (1943,
p. 10, figs. 13, 14) from the Topanga Formation, Miocene,
Santa Monica Mountains, Los Angeles Co., California.

Reinhart (1943, p. 58) doubted the record of the
occurrence of Anadara trilineata in the Empire Formation
which is of Pliocene age at Coos Bay, Oregon. Specimens
from those strata which we have seen appear to be identical
with A. trillineata except that they have about 29 radial
ribs. Reinhart did not recognize specimens referable to
A. trilineata in beds of Miocene age, but Hall (91) identi-
fied one specimen with this species from the Cierbo
Sandstone in the La Costa Valley quadrangle in west
central California and Stanton (Jour. Paleo., Vol. 40,
No. 1, p. 23, 1966) reported this species from the
Castaic Formation.

The fewer ribs as well as their beaded ornamenta-
tion and the slender umbos are features which serve to
separate Anadara trilineata from two somewhat similar
Miocene species, A. devincta Conrad (92) and A. monter-
eyana Osmont (93). The less convex valves and more
sharply projecting umbos as well as the usually beaded
character of the ribs are shell characters differing from
those of A. devincta montesanoana Etherington (94).

Species from the Miocene and Pliocene of Japan
have been recorded under the name of Arca trilineaia but
as pointed out by Reinhart (1943, pp. 59-60) those
fossils possess more numerous radial ribs (32-33), and
later they were referred to other species by Hatai and
Nisiyama (95).

Anadara amicula Yokoyama (96) from the late
Tertiary of Japan is a similar species. Kanno (97) in-
cluded eight species from Japan in the A. trilineata group,
occurring in strata from late Oligocene to Pliocene age.

Slodkewitsch (98) cited a species from the Pliocene
Kavrana series in Kamtschatka under the name of A.
trilineata but those records cannot be referred with
certainty to that species. Krishtofovich (99) mentioned a
fossil form which he cited as a subspecies of A. trilineata
with 29 to 34 ribs occurring in strata of early Pliocene
age in Sakhalin Island.

Anadara trilineata calcarea Grant and Gale
Plate 28, Figures 5, 7-10

Arca (Arca) trilineata Conrad variety calcarea Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 140,
pl. 2, figs, 6a, 6b, November 3, 1931. — Keen and
Bentson, Geol. Soc. Amer., Spec. Papers, No. 56, p. 26,
1944. Records of Grant and Gale cited.

Arca (Anadara) trilineata subsp. calcarea Grant and Gale,
Reinhart, Geol. Soc. Amer., Spec. Papers No. 47, p. 61,
pl. 9, figs. 6, 7, 8, 1943. “Pliocene of San Diego,
Calif.”’ Type locality also cited.

Arca trilineata calcarea Grant and Gale, Hertlein and
Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2, Pt. 1,

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

p. 59, 1944. “Near the Mexican Boundary about
three-quarters of a mile from the sea.”

Anadara trilineata Grant and Gale, Korobkov, Meto-
dicheskoe Rukovodstvo po Tretichnym Molluskam
Plastinchatozhabernye [Lamellibranchiata], (Leningrad),
pl. 55, fig. 4, 1954. Copy of pl. 2, fig. 6a of Grant and
Gale, 1931.

Anadara trilineata calcarea Grant and Gale, Vedder,
U. S. G. S., Prof. Paper 400-B, p. B327, 1960. San
Diego Formation. Also Niguel Formation.

Type specimen. — Holotype No. 436, Department
of Geology, Stanford University.

Type locality. — “‘San Diego well; Pliocene.”

Range. — Middle Pliocene (100) of southern Cali-
fornia.

Occurrence in San Diego Fm. — Well at San Diego
(Arca trilineata Conrad in part, of Dall). C.A.S. 1401,
1418, 12107.

Original description. — Shell like that of typical
Arca trilineata Conrad, but larger, much thicker, and
with more numerous cardinal grooves. (Grant and Gale.)

Remarks. — Reinhart (1943, p. 61) has added the
following pertinent remarks concerning this form: “In
addition, when viewed from above, the anterior end of
the shell of A. trilineata calcarea is bluntly pointed, dif-
fering from typical A. trilineata, which is sharply pointed.
This blunt point was acquired at a late stage in the growth
of the shell of A. trilineata calcarea as shown by the
growth lines.”

The differences between this subspecies and typical
Anadara trilineata are mostly the result of the large size,
thick shell and corresponding convexity of the valves.
Reinhart pointed out that several normal but rather large
specimens of A. trilineata s. s. were found at the type
locality of the subspecies A. ¢. calcarea.

About a dozen large specimens, mostly single
valves, are present in the collections at hand. They are
characteristic of the subspecies and possess about 26-27
radial, sulcated ribs and about 6 or 7 chevron-shaped
ligamental grooves. The largest valve, the anterior end
incomplete, from Loc. 1401 (CAS), south slope of Mount
Soledad, is 86.8 mm long, 70.8 mm high, convexity (one
valve), 30.8 mm. One from the San Diego well measures,
length 78 mm, height 66.5 mm, convexity (one valve),
24 mm.

Three valves, the largest one 83 mm long, from Loc.
2359 (UCLA), south slope of Mount Soledad, cited
among the locality records of Anadara trilineata, clearly
show the first stages of the rounding of the anterior end
which characterizes A. t calcarea. However, these valves
have not developed the extreme rounded anterior end
typical of A. t. calcarea. A specimen 59 mm long, typical
of A. trilineata, was collected at the same locality.

Grant and Gale recorded the subspecies Anadara
trilineata calcarea from strata of mid-Pliocene age in the
Santa Clara Valley in southern California. Richmond (101)
later reported its occurrence on Burruel Point, north-
western Santa Ana Mountains, Orange County, California,
about 50 feet above the base of the “Repetto (?)”
Formation.

[Anadara trilineata canalis Conrad]

Arca canalis Conrad, Proc. Acad. Nat. Sei. Philadelphia,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Vol. 8, No. 6, p. 314, dated December, 1856, but ap-
parently issued subsequent to April 25, 1857. “Santa
Barbara, Cal.” ‘Middle Tertiary.”” — Conrad, Pac.
Rail Road Expl., Vol. 6, Geol. Rept. 2, p. 70, pl. 2,
fig. 8, 1857. Same locality as originally cited. — J. P.
Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 3, p. 170,
1912. “San Diego-Purisima.” — J. P. Smith, Proc.
Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, p. 150, 1919.
“San Diego.” “Pliocene.”

Anadara (Anadara) trilineata subsp. canalis Conrad, Rein-
hart, Geol. Soc. Amer. Spec. Papers No. 47, p. 60,
pl. 7, figs. 3, 4, 1943. ‘“Purisima formation. Pliocene
of Capitola, Santa Cruz Co., Calif.”’ ““Known definitely
only from the Pliocene of California.”

Remarks. — The only records of the occurrence of
this subspecies in the San Diego Formation are those of
J. P. Smith. No specimens of this form were recognized
by us in any of the collections from the San Diego
Formation.

The subspecies Anadara trilineata canalis differs
from typical A. trilineata in that the length and height are
nearly equal. Reinhart (1943, p. 60) has given a good dis-
cussion of this form. According to him, A. &. canalis
occurs with typical A. trilineata at some localities but
that at Capitola and in Kettleman Hills, California, typical
A. trilineata apparently ranges somewhat higher strati-
graphically than does the form canalis.

GENUS BARBATIA GRAY

Barbatia Gray, Synopsis of the Contents of the British
Museum, ed. 42, p. 151, 1840; ed. 44, p. 81, 1842.
[No species cited. See Iredale, Proc. Malacol. Soc.
London, Vol. 10, Pt. 4, pp. 299, 303, 1913.] —
Gray, Proc. Zool. Soc. London for 1847, p. 197. Type
indicated as “‘A. barbata.’’ — Reinhart, Bull. Mus. Roy.
d’Hist. Nat. Belgique, Vol. 11, No. 13, p. 20, August,
1935. Type designated by Gray.

Type species (by subsequent designation, Gray,
1847). — Arca barbata Linnaeus [Syst. Nat., ed. 10, p.
693, 1758. “Habitat in M. Mediterraneo.” Illustrated by
Reeve, Conch. Icon., Vol. 2, Arca, sp. 83, pl. 13, fig. 83,
1844. “Hab. Mediterranean and other seas of Europe.”
— Bucquoy, Dautzenberg, and Dollfus, Moll. Mar. Rous-
sillon, Tome 2, Fase. 5 (Pelecypoda, Fase. 18), p. 182,
pl. 32, figs. 1-5 (typical), 6, 7, 8 (var.), 1891. Mediter-
ranean Sea to Cape Verde Islands. For a discussion of this
species see Dodge, Bull. Amer. Mus. Nat. Hist., Vol. 100,
Art. 1, pp. 144-145, 1952.]

Range. — Late Jurassic (Kimmeridgian (102) to
Recent. Recent world-wide in tropical and subtropical
waters, some members ranging into the warm temperate
zone. From the littoral zone to 183 meters (100 fathoms).
Occasionally deeper.

Description. — Shell of moderate size, not very
thick, inequilateral, elongately elliptical to subquadrate in
outline, a slight byssal gape at the ventral margin, beaks
anterior to center or subcentral; cardinal margin narrow;
ligament multivincular; sculpture consisting of radial
(often somewhat irregular) threads crossed by concentric
striae; exterior with a hairy (bearded) periostracum; teeth
increase in obliquity from the center to the ends of the
hinge; inner margin crenated or smooth.

Remarks. — Barbata differs from Arca s. s., type

157

Arca noae Linnaeus, in the usually rounded umbonal
angle, in the prosogyral beaks, the narrower ligamental
area, the more oblique teeth, and the slighter byssal gape.

Cucullaearca Conrad, according to Reinhart (103)
is “characterized by a large byssal gape, a wide, grooved
ligamental area which usually separates the anterior teeth
widely from the posterior ones, a widened posterior end,
and a fairly heavy shell.”

Abarbatia Dall, Bartsch and Rehder (104), based on
a Recent Hawaiian species, was described as “Like
Barbatia in ligamental and hinge characters, but differing
from it in not having the periostracum cut into fringes but
smooth.”

SUBGENUS FUGLERIA REINHART

Fugleria Reinhart, Jour. Paleo., Vol. 11, No. 3, p. 184,
April, 1937.

Type species (by original designation). — “Barbatia
(Fugleria) pseudoillota Reinhart, n. sp., from the Pliocene
of Fugler Point.” Pl. 28, figs. 6,9, 10.

Range. — Middle Pliocene to Recent.
tropical and subtropical waters.

Description. — The ligament of Fugleria is similar
to that of Acar, being confined chiefly to the posterior of
the beaks, but the hinge is different, the posterior teeth
of Fugleria being only feebly developed or even totally
absent, as in the type species. Fugleria, in addition, lacks
the elevated scars and reticulate sculpture of Acar.
(Reinhart, 1937).

Remarks. — This subgenus is here recorded from the
San Diego Formation for the first time.

The ligamental grooves on Barbarca Dall, Bartsch,
and Rehder (105), based upon a Hawaiian species, are
somewhat similar to those on Fugleria and the hinge has a
subumbonal edentulous area. Whether this Hawaiian
group is closely related to Fugleria is unknown.

Didimacar Iredale (106) also bears a general
resemblance to Fugleria in outline, ribbing, and ligamen-
tary grooves. It differs in that the hinge does not have an
edentulous area under the beaks, the muscle impressions
lack flanges and the periostracum is described as thin and
dark.

Recent in

Barbatia (Fugleria) illota Sowerby
Plate 27, Figures 35, 36, 38, 39, 40

Byssoarca illota Sowerby, Proc. Zool. Soc. London for
1833, p. 18, issued May 17, 1833.

Arca illota Sowerby, Reeve, Conch. Icon., Vol. 2, Arca,
sp. 78, pl. 12, fig. 78, 1844. ‘Hab. Gulf of Nicoiya,
Central America (found under stones); Cuming.”

Arca (Byssoarca) tabogensis C. B. Adams, Ann. Lyceum
Nat. Hist. New York, Vol. 5, pp. 486, 545 (separate,
pp. 263, 321), July, 1852. ‘Habitat. — Taboga and
Panama; C.B.A.!” ‘Under stones at low water.” —
Turner, Occas. Papers on Moll., Dept. Moll., Harvard
Univ., Vol. 2, No. 20, p. 90, pl. 19, figs. 7, 8, 1956.
Original record cited.

Barbatia (Acar) illota Sowerby, Maury, Palaeontogr.
Americana, Vol. 1, No. 4, p. 182 (20), pl. 30 (2), figs.
8, 14, 1922. ‘Panama (Newcomb coll.); Bucarn
| Bucaru], Los Santos Province; and the northeast point
of Viveros Island, Islas de las Perlas (Olsson coll.)”. —

158

Durham, Geol. Soc. Amer., Mem. 43, Pt. 2, p. 54, pl. 1,
fig. 6 1950. Cited from San Marcos Island, and Santa
Inez Bay, Lower California, Pleistocene.

Barbatia (Fugleria) illota Sowerby, Rost, Allan Hancock
Pac. Exped., Vol. 20, No. 2, p. 187, pl. 11, figs. 6-8,
text figs. 83a-c, 1955. “Isla Angel de la Guarda, Gulf
of California, to Lobitos, Peru”; intertidal zone at-
tached to rocks, to a depth of 40 fathoms.

Fugleria illota Sowerby, Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 83, pl. 6, figs. 1-1b, 1961. Gulf of California to
northern Peru.

Type specimen. — British Museum (Natural History)?

Type locality. —“‘Hab in America Centrali.” ‘“‘Found
under stones in the Gulf of Nocoiyo.” [Costa Rica. ]

Range. — Middle Pliocene to Recent. Recent from
Punta Penasco, Sonora, Mexico, to Lobitos, Peru, and the
Galapagos Islands, from intertidal zone, attached to rocks,
to a depth of 73 meters (40 fathoms).

Occurrence in San Diego Fm. — C.A.S. 28893.
L.A.M. 305, 305A.

Original description. — Byss. testa ovata, alba,
radiatim costata, costis numerosis, decussatis; epidermide
fusca, foliacea induta; latere antico breviore, rotundato,
postico declivi; area ligamenti angusta, brevi: long. 1.5,
lat. 0.75, alt. 1, poll. (Sowerby.)

Remarks. — More than 100 specimens of a small
arcid collected by Kanakoff at Loc. 305 (LAM) are here
assigned to Barbatia (Fugleria) illota, These vary in length
from 3 to 20 mm. The shape is somewhat variable. On
small specimens teeth are present along the entire hinge
but on large specimens the posterior portion of the hinge
is devoid of teeth except for four or five at the end. As
mentioned by Rost the teeth are striated. The ligamental
grooves on small specimens are posterior to the beak, but
larger specimens (35 mm long) have as many as seven
ligamental grooves, the upper ones not extending beyond
the beak but the three lower ones forming asymmetric
angles extending anterior to the umbo. The largest Recent
specimen which we have seen is from Loc. 31389 (CAS).
It was collected by W. D. Clark at Venado Island, Panama,
and is 39 mm long, 25 mm high, the convexity (both
valves together), 18.6 mm.

The present species has been recorded from beds of
Pleistocene age in the Gulf of California region as well as
in Panama and in Ecuador. The present record is the
first of its occurrence in beds of Pliocene age.

The records of Melvill and Standen (107) of the
doubtful occurrence of this species in the Persian Gulf are
referable to some other species.

Barbatia (Fugleria) pseudoillota Reinhart (108)
described from Pliocene strata near Santa Maria in Santa
Barbara County, California, is a very similar species. The
type specimen, a right valve, is 33.5 mm long, 31 mm
high, and the convexity is 9 mm. It was described as less
elongate than B. (F.) illota with about seven granular
teeth anteriorly but completely lacking teeth on the
hinge posteriorly. Our observations on the hinge of adult
Recent specimens of B. (F.) illota agree with those of
Reinhart, Woodring, and Rost, namely: that although
there is a long edentulous area in the subumbonal area
there are a few teeth at the posterior end.

Perhaps a large series of Barbatia (Fugleria)
pseudoillota may reveal specimens with teeth on the

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

posterior end of the hinge but none of such have been
reported.

Barbatia (Fugleria) tenera C. B. Adams (109), of
which B. balesi Pilsbry and McLean (110) is a synonym,
from the Floridan and Caribbean region is similar to
B. (F.) illota. The fossils described as Arca (Acar)
millifilia Dall (111) from ‘Pliocene of Shell Creek,
Florida,” and a varietal form B. (A.) m. latrinidadis
Maury (112), from the “‘Pliocene” of ““Matura”’, Trinidad,
were compared by their authors with B. (F.) illota.

FAMILY GLYCYMERIDIDAE NEWTON (113)

Shell orbicular, subtrigonal or subquadrate, equi-
lateral, valves closed; isomyarian, integripalliate; beaks
usually orthogyrate, located nearly centrally or slightly to
the posterior; ligament external, made up of chevron-
shaped parts; hinge plate arched; teeth taxodont, absent or
small and transverse at center, side teeth oblique or
parallel to hinge, the larger ones chevron-shaped, internal
ventral margin usually crenulated; exterior smooth or
with radial ornamentation; shell material porcelaneous.
(Adapted from Nicol, Jour. Paleo., Vol. 19, p. 616, 1945.)
Cretaceous to Recent.

Remarks. — Bowden and Heppell (114) recently
discussed the usage of the family names “Glycymeridae”
and “Glycimeridae.” The earliest valid usage of
“Glycymeridae” for the present family is by Newton,
1916. Stenzel, Krause, and Twining (115), pointed out
that the correct spelling for this name is Glycymerididae.
The family name Glycimeridae attributed to Deshayes
(116) (“Les Glycimerides.”, vernacular) by Chenu and
others is now synonymous with Hiatellidae Gray, 1824.

Nicol has contributed several papers dealing with
this family. These include one dealing with the
phylogeny (117) of the Glyeymerididae, one summarizing
the genera (118) and subgenera, and one dealing with
distribution of living glycymerids. (119)

A paper by Baldi (120) deals with the species of
Glycymeris s. str. of Oligocene and Miocene age in Europe.

GENUS GLYCYMERIS DA COSTA

Glycymeris Da Costa, Hist. Nat. Test. Brit., p. 168, 1778.
Species cited: ‘‘G. orbicularis,” pl. 11, figs. 2, 2. In
synonymy, “Chama glycymeris Bellon,” reference to
Lister, Hist. Conch., tab. 247, fig. 82. Also other
references including Pennant, Brit. Zool., No. 58, tab.
58, fig. 58. “Arca. Glycymeris. Orbicular.”

Not Glycymeris Lamarck, 1799 (= Panope Ménard, 1807).

Axinaea Poli, Test. Utrius. Sicil., Vol. 1, p. 32,1791. Sole
species: Arca pilosa [Linnaeus]. Type (designated by
Gray, Proc. Zool. Soc. London for 1847, p. 198):
“Arca pilosa.” { Linnaeus. |

Axinaeoderma Poli, Test. Utrius. Sicil., Vol. 2, pp. 254,
260, 1795. ‘‘Arca pilosa Linn.”

Pectunculus Lamarck, Mém. Soc. Hist. Nat. Paris, Vol. 1,
p. 87, 1799. Sole species: ‘‘Arca pectunculus. Lin.”
See remarks by Dall, Proc. Malacol. Soe. London,
Vol. 10, Pt. 3, pp. 255-256, 1912.

Not Pectunculus Da Costa, 1778.
Veneracea).

Type species (by tautonomy). — Chama glycymeris

Bellon [= Arca glycymeris Linnaeus, Syst. Nat., ed. 10,

(In superfamily

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

p. 695, 1758. “Habitat ad insulam Garnsey.” Illustrated
by Reeve, Conch. Icon., Vol. 1, Pectunculus, pl. 3, figs.
12a-b, 1843. Coasts of Britain. For a discussion of this
species, see Dodge, H., Bull. Amer. Mus. Nat, Hist., Vol.
100, Art. 1, p. 157, 1952.]

Range. — Cretaceous to Recent. Recent, world-wide
in warm and temperate marine waters (but not in Arctic
and Antarctic), in 0-640 meters (0-350 fathoms), but
usually in less than 110 meters (60 fathoms). One
species reported from a depth of 1846 meters (1010
fathoms).

Description. — Shell suborbicular to subtrigonal in
outline, slightly truncated posteriorly; cardinal area with
chevron-shaped ligamental grooves; hinge curved, set with
transverse teeth which are larger and more horizontal
toward the outer margins; gradual subsidence of ligamental
area during growth results in progressive obliteration of
teeth along dorsal margin; posterior adductor impression
with a slight flange.

Remarks. — The usage by various authors of the
names Glycymeris and Pectunculus was discussed by
Chavan (121). He also discussed (122) the muscular im-
pressions of Glycymeris.

The genus Glycymeris apparently reached its
greatest development in number and distribution of
species during Miocene time. A number of species have
been described from Tertiary strata of California but only
two are known to occur in the San Diego Formation.

About 100 species of Glycymeris (sensu lato) live
in tropical, subtropical and temperate waters, frequently
on sand or on a sandy, muddy bottom. Fifteen species
and subspecies have been described from west American
waters.

SUBGENUS AXINOLA N. SUBGEN.

Type species. — Axinaea (?septentrionalis, var.)
subobsoleta Carpenter, Rept. Brit. Assoc. Adv. Sci. for
1863, pp. 627, 644, August, 1864. (Reprint in Smith-
sonian Misc. Coll., No. 252, pp. 113, 130, 1872). Cited
from Oregon; region between San Diego and San Pedro,
California; islands off the coast of California; Vancouver,
British Columbia. — Carpenter, Ann. Mag. Nat. Hist.,
Ser. 3, Vol. 14 (Nos. 5-37), p. 425, December, 1864.
Reprint in Smithsonian Misc. Coll., No. 252, p. 237,
1852. “Hab. Neeah Bay (Swan); Shoalwater Bay
(Cooper).”’ For a discussion and illustration of this
species see K. V. W. Palmer, Geol. Soc. Amer., Mem. 76,
p. 63, pl. 1, figs. 8-10, 1958. “Recent. Neah Bay,
Washington (type).”

Range. — Late Eocene to Recent.
Lower California, Mexico, to Japan.

Description. — Shell small to moderate size (5 to
50 mm long), subtrigonal to suborbicular in outline,
often produced posteriorly, convexity of valves slight,
thin, sometimes chalky, the Recent species covered with
a velvety periostracum; the exterior is smooth or with
faint rather narrow, flat-topped radial ribs which become
strongly accentuated by erosion; beaks usually opistho-
gyrate but in some species orthogyrate; cardinal area short,
high, with ligamentary grooves forming asymetrical
triangles, the anterior side the longer; hinge arcuate, the
central teeth much finer than those at either end or some-
times nearly obsolete; interior ventral margin of valves

Recent from

159

crenulated, the crenulations with blunt ends.

Remarks. — At the time that the senior author and
A. M. Strong studied the tropical west American species
of Glycymeris it became evident to us that a group of
species typified by G. subobsoleta, differed in shell
characters from any described supraspecific unit. Later
Dr. David Nicol came to the same conclusion during his
study of the family Glycymerididae. The group of species,
both Recent and fossil, here included in Axinola, appear
to be confined to the borders of the northeastern Pacific
region.

The combination of shell characters including the
outline and the narrow, high cardinal area with decidedly
asymmetrical ligamental grooves, and fine sculpture of the
exterior differentiate Axinola from such groups as
Veletuceta Iredale (123) and Glycymerula Finlay and
Marwick (124).

The identification of the species in this group is
fraught with difficulty. Willett (1944, p. 108) pointed
out that this is caused by “the great amount of individual
variation within the species. This applies not only to the
shape, color and sculpture, but to the number of teeth,
width of hinge-plate, width of ligamental area, and size and
prominence of the umbos. Also there may be considerable
morphological change between juvenility and maturity.
There is often more similarity between the young of dif-
ferent species than there is between the adults; therefore,
many young specimens are very difficult, if not im-
possible to identify.”

Key to Species of Axinola

A. Umbos high, prominent;

apical angle 83° to 88° . profunda
B. Umbos low, often flattened;
apical angle 93° to 106° grewinghi

Glycymeris (Axinola) grewingki Dall
Plate 27, Figures 14, 19, 22, 24

Glycymeris grewingki Dall, U. S. G. S., Prof. Paper 59,
p. 107, pl. 2, fig. 13, April 2, 1909. — Stewart, in
Woodring, Stewart, and Richards, U. S. G. S., Prof.
Paper 195, p. 90, pl. 29, figs. 10, 11; pl. 33, figs. 7, 8,
issued June 7, 1941. “Etchegoin formation of North
Dome,” Kettleman Hills. — Weaver, Univ. Washington
Publ. Geol., Vol. 5, Pt. 1, p. 62, pl. 10, fig. 19, 1942
(issued December 31, 1943). (Holotype.)

Glycymeris coalingensis Arnold, U. S. G. S., Bull. 396,
p. 80, pl. 19, fig. 3, 1909 (issued January 10, 1910).
Loc. 4806 (U.S. G. S.), “Glycymeris bed on north side
Alcalde Canyon, 2 miles northeast of Alcalde, center
of SW. 1/4 sec. 7, T. 21 S.,R.15 E.” [M.D.B.M.]
Coalinga district, California.’ ‘“‘Etchegoin formation,
upper Miocene.” [Pliocene.] — Arnold, in Eldridge
and Arnold, U.S. G.S., Bull. 398, p. 131, pl. 41, fig. 3,
1910. (Holotype.) — Clark, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 8, No. 22, checklist opposite p. 400,
pl. 48, figs. 9, 10, 1914. Upper and Lower San Pablo,
late Miocene. — Slodkewitsch, Acad. Sci. USSR, Paleo.
Inst., Paleo. USSR, Vol. 10, Pt. 3, Fasc. 18, p. 137;
Fasc. 19, pp. 104, 212, pl. 9, fig. 4, 1938. (Copy of
Arnold’s pl. 41, fig. 3.) — Hall, Univ. Calif. Publ. Geol.

160

Sci., Vol. 34, No. 1, p. 50, pl. 1, figs. 1, 2, 3, 4, 1958.
Oursan Formation, Pleasanton area, California, middle
Miocene.

Type specimen. — No. 107784, United States
National Museum.

Type Locality. — ““Miocene of Coos Bay, Oregon.”
[ Pliocene. ]

Range. — Middle Miocene (Oursan Formation) to
middle Pliocene.

Occurrence in San Diego Fm. — C.A.S. 1400.
L.A.M. 305. S.D. 4, 150. U.C.L.A. 1386. S.D.S.C. 32,
223.

Original description. — Shell solid, suborbicular,
subequilateral, equivalve; beaks prominent, moderately
convex, slightly separated by the area, which is narrow, in
each valve forming a wide, very obtuse triangle with
deeply incised angular sulci, radiating from the vertical of
the beak; anterior slope slightly shorter and more rounded
than the posterior, which is somewhat produced toward
the lower portion; there is no distinct lunule or escutcheon;
but a feebly differentiated anterior dorsal area is
characterized by radial threads much finer than those on
the anterior half of the disk; on the latter are about a
dozen flat, little-elevated, radial ribs, separated by much
narrower, channeled sulci, the whole with more or less
obsolete fine radial striation; these radial ribs are distinct
when the surface of the shell is intact; the anterior half of
the disk, except when decorticated, nearly smooth except
for close-set uniform numerous radial threads which cover
the entire surface; when decorticated the internal struc-
ture shows ribs much like those normally exposed on the
anterior half of the disk. Altitude of figured specimen,
38 mm; longitude, 38 mm; diameter 20 mm. (Dall.)

Remarks. — A few specimens from the San Diego
Formation are flatter and more rounded than those of
typical G. profunda. The umbos do not curve over the
cardinal area which bears finer ligamental grooves and the
apical angle is about 100°. These resemble G. grewinghki
Dall, especially those specimens illustrated by Stewart
from late Pliocene strata on North Dome, Kettleman Hills,
California. Some of the larger, more rounded specimens
of G. grewingki illustrated by Stewart (pl. 33, figs. 7, 8)
have an apical angle of about 120°. Glycymeris coaling-
ensis Arnold is a synonym. Stewart stated (1941, p. 90)
“.. . the differences between G. coalingensis and G.
grewingki cited by Arnold being due to differences in the
state of preservation of the type specimens.” Large
specimens from the coalinga area are 41 mm high.

Stewart suggested the possibility that some of the
specimens from Kettleman Hills which he identified as
G. grewingki might be a flat variety of G. profunda. The
relationship of G. grewingki with the Recent forms
described by Dall from southern California is not known.

The present specimens differ from G. subobsoleta
Carpenter (125), a Recent species, in the higher umbos
and correspondingly wider (dorsal-ventral) ligamental area
and less prolongation posteriorly.

Willett pointed out that representatives of Glycymeris
subobsoleta Carpenter in southern California often lack
or nearly lack posterior elongation and the apical angle is
about 90°. Presumably those southern shells would be
referable to G. corteziana Dall (126) as interpreted by
Woodring, Bramlette, and Kew, who gave the range of G.
subobsoleta as Alaska to Oregon and that of G. corteziana

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(considered to be a southern race of G. subobsoleta) as
Forrester Island, Alaska, to Magdalena Bay, Lower
California. They considered G. migueliana Dall (127)
to be a synonym of G. corteziana.

The present flattish specimens bear considerable
resemblance to G. migueliana Dall and its probable
synonym G. corteziana Dall, the types of which were
illustrated by Willett. The name G. migueliana has line
priority over the name G. corteziana on the page con-
taining the original description. Whatever the relation-
ship may be the names Glycymeris subobsoleta, G.
profunda, G. grewingki and G. coalingensis all have
priority over G. migueliana and G. corteziana.

Glycymeris vancouverensis Clark and Arnold (128),
another member of this group described from the Sooke
Formation on Vancouver Island, British Columbia, of late
Oligocene or early Miocene age, was said to be closely
related to G. migueliana but higher in proportion to the
length and with a smaller apical angle.

Slodkewitsch (1938, pp. 104, 212, pl. 9, figs. 5, 5a)
cited a species under the name of Glycymeris coalingensis
from beds of Pliocene age in Kamtschatka but we have
not seen specimens from that region.

Glycymeris (Axinola) profunda Dall
Plate 27, Figures 15, 20, 21, 23, 25, 28, 29, 30, 34, 37

Axinea profunda Dall, Proc. U. S. Nat. Mus., Vol. 1, p. 13,
July 1, 1878. — Schuchert et alii, U. S. Nat. Mus., Bull.
53, Pt. 1, p. 86, 1905. ‘Pliocene, San Diego, Califor-
nia.”” [Pleistocene.] — Keen and Bentson, Geol. Soc.
Amer., Spec. Papers No. 56, p. 31, 1944. Earlier
records cited.

Glycymeris septentrionalis {Middendorff], Hertlein, Stan-
ford Univ. Bull., Ser. 5, No. 78, p. 82, 1929. “San
Diego Pliocene.”

Not Pectunculus septentrionalis Middendorff, 1849 [=
Glycymeris multicostata Sowerby, 1833 (see Hertlein
and Strong, Zoologica, Vol. 28, Pt. 3, No. 19, p. 151,
1943) ].

Glycimeris profunda Dall, Willett, Bull. South. Calif.
Acad. Sci., Vol. 42, Pt. 3, p. 111, pl. 11, figs. 3, 3a,
September-December, 1943 (issued January 15, 1944).
“taken in 200 fathoms off Santa Catalina Island,” and
“in 25 fathoms off Redondo, Los Angeles County.”
“Common in some Lower Pleistocene deposits,
particularly so at Hill Top Quarry, San Pedro.”

Glycymeris profunda Dall, Woodring, Bramlette, and
Kew, U. S. G. S., Prof. Paper 207, p. 79, pl. 30, figs.
5-8, 1946. ‘Lomita Marl” at “Hilltop Quarry,” also
in “‘San Pedro sand,” early Pleistocene.

Type specimen. — Lectotype from type lot No.

7935, United States National Museum.

Type locality. — Indicated as from ‘San Diego”

(p. 11). On p. 29, cited from “recent alluvial soil, eight or

ten feet above tide-water, is another stratum (D), in which

the specimens are in a poor state of preservation.”’ [ Ac-

cording to Woodring, Bramlette, and Kew (1946, p. 79),

“The type material was collected evidently from the

Pleistocene strata overlying the Pliocene San Diego forma-

tion at Pacific Beach.’’ |

Range. — Middle Pliocene to Recent. Recent from

off Redondo and off Catalina Island, California, in 46

to 366 meters (25 to 200 fathoms).

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Occurrence in San Diego Fm. — C.A.S. 28886.
L.A.M. 124, 302, 305, 305A. S.D.S.C. 223.

Original description. — Shell subtriangular, ventral
margin rounded, umbos erect, rather small. Area narrow,
deep; marked by five or six lines meeting at an angle in
the verticle of the umbo, one above another; anterior
lines somewhat the shortest; exterior marked by twenty-
five or thirty flattened ribs, separated by deep channels
one-fourth as wide as the ribs, and by which the interior
margin is crenulated. The ribs are crossed by thread-like
close lines of growth, which may be elevated or obsolete
on the ribs, but are sharply defined in the channels, which
they partially fill up in some specimens. Toward the
anterior and posterior margins, the sculpture is nearly
obsolete. In eroded examples, this sculpture may be en-
tirely altered, and such are hardly recognizable as the same
thing. Interior smooth or lightly radiately striate, with a
tendency to an elevated narrow ridge behind the anterior
scar; hinge with teeth placed as if radiating from the centre
of the valve, six to nine anteriorly, and ten to fourteen
posteriorly, with some ten or twelve small, crowded teeth
between the two radiating sets, and placed perpendicularly
and parallel with one another. Height, 32 mm;length,
30 mm; thickness, 20 mm; the last proportionally
greater in the young. (Dall.)

Remarks. — Glycymeris profunda is represented in
collections from the San Diego formation from several
localities, the largest number from Loc. 305 (LAM) near
the Mexican boundary. There are over two hundred
specimens from that locality varying in size from about
4 to 28 mm in height.

These specimens are high, thick, rounded trigonal,
convex valves with high prominent umbos, the beaks
curving over the rather wide (dorsal-ventral) cardinal area.
The ligamental grooves are asymmetrical and on the more
globose specimens rather coarse. The exterior of the shell
is smooth when the preservation is perfect. Usually, how-
ever, removal of the outer layer by erosion exposes radial
ribbing. Some of the globose valves agree almost
exactly with specimens from the Pleistocene at Pacific
Beach, part of the original lot of Glycymeris profunda
which bear numbers 696 and 696a (see plate 27, figs. 15,
23, 28, 29) in the type collection of the Department of
Paleontology of the California Academy of Sciences. One
of the larger specimens in that lot is 23 mm long, 23.4 mm
high, convexity (one valve), 9.3 mm, apical angle about
100°. The arcuate hinge bears about 22 teeth. Many of
the specimens in the present collections agree with the
illustrations of G. profunda from beds of Pleistocene age
in the San Pedro region, published by Woodring, Bramlette,
and Kew.

Arnold (129) illustrated two specimens from the
Pleistocene of San Pedro, one cited as G. barbarensis
Conrad (fig. 9) and one as G. septentrionalis Middendorff
(fig. 10). Willett considered both of these to be referable
to G. profunda. Woodring, Bramlette, and Kew stated
that Arnold’s figure nine was similar to but of less height
than typical G. profunda. Most of the specimens in the
present collections from San Diego bear a similarity to
Arnold’s figure nine, but some, especially the flatter,
higher ones, are similar to his figure 10. Judging from the
variation in the globosity, height, and character of the
ligamental grooves revealed in the series of specimens at
hand, support is given to Willett’s suggestion that both of

161

Arnold’s figures may be referable to G. profunda.

The identification of Glycymeris barbarensis Con-
rad (130) described over a century ago is involved in
nomenclatorial problems because two different species
were described under that name. No locality was cited
by Conrad for the species illustrated in volume 6 of the
Pacific Railroad Reports except that the title refers to
“Tertiary Fossils” and in the text “California fossils’’,
which Conrad believed “‘appear to represent the Miocene
period” (131). The specific name would imply that it was
believed to have been found in the Santa Barbara region.
Woodring, Bramlette, and Kew ventured the opinion that
the fossil, presumably of Pleistocene age, illustrated by
Conrad is a possible synonym of the Recent G. subobsoleta
Carpenter. Whatever the identification of G. barbarensis,
it definitely appears to be distinct from typical G. pro-
funda. According to Woodring, Bramlette, and Kew, the
species cited under the name of Axinaea barbarensis in
volume 7 of the Pacific Railroad Reports is probably
referable to Glycymeris veatchii Gabb.

Glycymeris subobsoleta Carpenter (see K. V. W.
Palmer, 1958, p. 63, pl. 1, figs. 8-10) has a thin shell
which is elongated posteriorly and has a narrow cardinal
area. The shell characters of some young specimens of
G. profunda approach those of G. subobsoleta and G.
grewinghki.

Glycymeris tenuimbricata Clark (132), a species
with high slender umbos, from the San Ramon beds of
late Oligocene or early Miocene age, has an apical angle of
about 90° and bears a general resemblance to some
specimens of G. profunda, but it has a much narrower
cardinal area.

Glycymeris keenae Willett (133) from Alaska was
described as a small (13.5 mm long) white shell with con-
centric sculpture and an angular hinge plate. Its general
features are similar to those of G. profunda and allied
species.

In addition to the occurrences at San Diego and
San Pedro, California, G. profunda has been reported (the
identifications mostly doubtful) from beds of Pleistocene
age from Cayucos, California, to northern Lower California.

ORDER DYSODONTIDA NEUMAYR (FISCHER)
SUPERFAMILY MYTILACEA RAFINESQUE (134)
FAMILY MYTILIDAE RAFINESQUE (135)

Shell elongately ovate, bullet to wedge-shaped, often
with an oblique axis, the valves equal. Beaks small,
prosogyrate, placed usually near the anterior end, the
umbonal slope posteriorly, often prominent and vaulted.
Hinge line posterior of the beaks usually straight, plain
or with a crenulated margin in harmony with a ribbed
external sculpture, edentulous, or with small dysodont
teeth on the anterior lunular margin below the beaks.
Ligament subinternal, attached to an elongated calcified
resilifer, usually white in color, compact or with pitted or
cellular basal foundation. Typically dimyarian, the
anterior adductor scar is always much smaller than the
other and sometimes wholly eliminated in the adult,
hence the posterior adductor scar is large and sometimes
confluent with that of the posterior retractor. Surface
smooth or with radial riblets; the sculpture is usually
much stronger on the posterior-dorsal side, finer on the
ventral side of the umbonal slope. Inner layer of the shell

162

is ordinarily nacreous, the outer layer thinner, darker,
and covered by a thin or heavy, yellow, brown, green or
black periostracum, hairy or bristly, often peeling off from
dead valves. Marine, brackish to freshwater. (Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York, pp. 110-111, 1961.) Devonian to
Recent.

Remarks. — The members of this family are often
attached by a byssus or, as mentioned by Tryon, they
frequently conceal themselves by spinning a byssal nest
of sand and shell fragments, or they live in the burrows of
other mollusks, or they burrow into soft substances.

Newell (136) discussed members of this family oc-
curring in the late Paleozoic and Cox (137) remarked on
the derivation of some of the genera in the Mesozoic Era.

A monograph by Soot-Ryen (138) dealing with the
Recent west American species of this family appeared in
1955. He recognized 56 species which he distributed in
23 genera and 6 subgenera.

This family is represented in the San Diego formation
by seven genera.

Key to Genera of Mytilidae

A. Sculpture divided into three
distinct areas Gregariella
B. Sculpture not divided into
three areas; or smooth

a. Beaks terminal or nearly so;
teeth on anterior portion of
hinge

b. Interior with a small,
triangular septum under
the beaks SES ots

bb. Interior lacking septum
under the beaks

. Septifer

c. Shell usually not exceeding
3.5 mm in length; ovate
with fine, even, radial
sculpture we NSE

ce. Shell exceeding 3.5 mm in
length; often elongated or
cuneiform

. Crenella

d. Margin strongly crenellated
posterior to the ligament;
radial sculpture coarse on
dorsal, fine on ventral area.

dd. Margin posterior to the liga-
ment smooth; exterior smooth
or occasionally with radial
sculpture

Aeidimytilus

Mytilus

aa. Beaks not terminal; teeth lacking
on anterior portion of hinge

. Modiolus

ec. Shell obliquely oblong . ;
. Lithophaga

ec. Shell subeylindrical .

GENUS MYTILUS LINNAEUS

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Mytilus Linnaeus, Syst. Nat., ed. 10, p. 704, 1758.
Seventeen species cited including Mytilus edulis. —
Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ. No. 3,
p. 95, 1930. Anton’s designation of Mytilus edulis as
type accepted. — Cox, Mem. Geol. Surv. India, Palaeo.
Indica, Ser. 9, Vol. 3, Pt. 3, p. 74, 1940. “Genotype.
— Mytilus edulis Linné (1758, p. 705), Recent, Euro-
pean Seas.”

Type species (designated by Anton, Verzeich.
Conchyl., p. 17, 1839). — Mytilus edulis Linnaeus.
Mytilus with M. edulis designated as type by Anton was
placed on the Official List of Genera by the Internatl.
Comm. Zool. Nomencl., Opinion 94, in 1926. [Mytilus
edulis Linnaeus, Syst. Nat., ed. 10, p. 705, 1758. ‘‘Habitat
in O. Europaeo, Indico & M. Balthico”. Ref. to Lister,
Conch., 3, t. 362, fig. 20; Gualtieri, Test., t. 91, fig. E;
also others. — Bucquoy, Dautzenberg, and Dollfus,
Moll. Mar. Roussillon, Vol. 2, Fase. 4, p. 136, pl. 26, figs.
1-4, 1890. Mediterranean region, Black Sea, and England. ]

Range. — Jurassic to Recent. Recent, world wide,
from the intertidal zone to about 91 meters (50 fathoms).

Description. — Shell elongated and with terminal
or subterminal pointed beaks; a thin nacreous layer
present; valves with ventral margin nearly straight but
wider and rounded posteriorly, gaping slightly for a
byssus; smooth or radially sculptured; periostracum con-
spicuous; a few small teeth on a very small plate beneath
the beaks or edentulous (lacking in some Mesozoic
forms); anterior adductor impression small or lacking,
high in umbonal cavity; posterior adductor impression
larger, bilobed; pallial line not parallel to margin of valves.

Remarks. — Most species of the Mytilidae in the
Cenozoic are readily referable to Mytilus or Modiolus.
Among the Mesozoic forms, as pointed out by Cox
(1940, p. 75), the differences in shell characters between
the two are less distinct and there are fossil as well as
Recent forms whose shell characters are intermediate be-
tween the two genera. The same author mentioned that
from present knowledge of fossil forms of this group it
appears that Mytilus descended from Modiolus.

Three species of Mytilus have been recorded as oc-
curring in strata of Pliocene age in California, two of
which have been reported from the San Diego formation.

Key to Subgenera of Mytilus

A. Anterior adductor impression
small and shallow: anterior

ventral margin smooth . . Mytilus s. s.
B. Anterior adductor impression

large and deep; anterior ventral

margin minutely crenulated Crenomytilus

[SUBGENUS MYTILUS S. S.]
[Mytilus edulis Linnaeus]

Mytilus edulis Linnaeus, Syst. Nat., ed. 10, p. 705,
1758. [Mytilus edulis was placed on the Official List
of specific names in Zoology by the Internatl. Comm.
Zool. Nomencl. in Opinion 333, signed July 8, 1954,
published February 23, 1955.] — I. S. Oldroyd, Stan-
ford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 66,
pl. 27, fig. 4, 1924. “In the Pliocene, Benicia,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Solano County, and San Diego, California.” — Dodge,
Bull. Amer. Mus. Nat. Hist., Vol. 100, Art. 1, p. 213,
1952. Cosmopolitan. — Soot-Ryen, Alan Hancock Pac.
Exped., Vol. 20, No. 1, p. 19, pl. 1, figs. 1, 2, text
figs. 1, 2, 10, 11, 1955. Cosmopolitan.

Type locality. — “Habitat in O Europaeo, Indico &
M. Balthico.””

Remarks. — The only record of the occurrence of
Mytilus edulis in the Pliocene at San Diego is that of I. S.
Oldroyd. We have not observed any specimens in the
collections from the San Diego Formation which are
referable to this species and we are therefore unable to
validate the record of Oldroyd.

This species has been recorded from several other
localities in California in strata of Pliocene age including
the Falor Formation, Merced Formation, San Joaquin
Formation (cf.), and in the Fourth Street Tunnel in Los
Angeles. It also has been recorded as occurring from
middle Miocene (139) to Recent in this region.

Mytilus edulis, or subspecies of it, occur in most of
the seas of the world except in extreme tropical waters.
Field (140) gave an extensive discussion of its biology and
economic value and Seed (141) recently discussed the
variation in the shape of the shell of this species.

SUBGENUS CRENOMYTILUS SOOT-RYEN

Crenomytilus Soot-Ryen, Allan Haneock Pac. Exped.,
Vol. 20, No. 1, p. 23 November 10, 1955. “Type of
genus: Mytilus grayanus Dunker, 1853.”

Mytiloconcha of west American authors, not Mytiloconcha
Conrad, 1862.

Type species (by original designation). — Mytilus
grayanus Dunker [Zeitschr. f. Malakozool., Jahrg. 10,
No. 6, p. 84, July, 1853. ‘Habitat ad insulam Javam.”
Illustrated by Soot-Ryen, 1955, p. 24, pl. 2, figs. 9, 10,
text fig. 7. Japan. — Habe and Ito, Shells of the world in
colour, Vol. 1, The northern Pacific (Hoikusha: Osaka,
Japan), p. 112, pl. 36, fig. 5, 1965].

Range. — Late Oligocene or early Miocene to Recent.

Original description. — Shell mytiliform with
terminal umbones, lunule grooved and incurved, forming
two to three large teeth usually obsolete in old specimens,
as there is a pronounced tendency to a growth in thickness
by depositing new shell material on the inside of the
valves. Margins, especially the anteroventral one, finely
crenulated, the crenulations apparently formed as a
result of the building up of the crystals in the valves; shell
obliquely striated, especially distinct on the ventral sur-
face. Resilial ridge compact; anterior adductor strong,
showing a distinct thickened scar; anterior retractor scar
elongate behind umbo; posterior adductor and retractor
scars continuous. The soft parts have not been studied.
(Soot-Ryen, 1955.)

This group of mytiliform species is distinguished
from similar forms by the compact resilial ridge, the
strong anterior adductor and the fine crenulation of the
margins. (Soot-Ryen.)

Remarks. — West American Tertiary species referred
to Crenomytilus by Soot-Ryen are: Mytilus mathewsonii
Gabb, M. trampasensis Clark, M. kewi Nomland, and M.
coalingensis Arnold. The new subspecies, M. coalingensis
sternbergi, obviously belongs with this group of species.
Mytilus schencki Hanna and Hertlein, described from

163

strata of late Miocene age, is probably referable to the
subgenus Crenomytilus but we have not seen specimens
in which uneroded margins could be observed. The only
Recent species referred to this subgenus by Soot-Ryen
was the type species, M. grayanus Dunker (M. dunkeri
Reeve), from Japan and neighboring regions.

Mytilus (Crenomytilus) coalingensis sternbergi
n. subsp.
Plate 41, Figures 10, 14

Mytilus coalingensis Arnold, Hertlein, Stanford Univ. Bull.,
Ser. 5, No. 78, p. 85, 1929. “San Diego fauna’’.
“Pliocene.”” — Vedder, U. S. G. S., Prof. Paper 400-B,
p. B327, 1960. “San Diego formation.” Also Niguel
Formation and Careaga Sandstone and upper part of
Foxen Mudstone.

Not Mytilus (Mytiloconcha) coalingensis Arnold, U.S. G. S.,
Bull. 396, p. 73, pl. 19, fig. 5; pl. 22, fig. 6, 1909
[issued January 10, 1910]. Type locality 4656, (see
p. 33), “at northwest end of Anticline Ridge, 6 miles
north-northeast of Coalinga, SW. 1/4 sec. 34, T. 19 S.,
R. 15 E.” [Mount Diablo Base and Meridian].
“Lowest Etchegoin bed or Glycymeris zone, just below
bed of 4657.” “Etchegoin (upper Miocene).”’ [ Pliocene. ]

Mytilus sp. (large), Hertlein and Allison, Bull. South.
Calif. Acad. Sci., Vol. 58, Pt. 1, January-April, p. 21,
issued May 11, 1959. Three localities between
kilometer marker 258, Ensenada-San Quintin highway,
to terrace east of San Simon and Agua Chiquita, north-
western Lower California, late Pliocene.

Type specimen. — Holotype, Los Angeles County
Museum, from Loc. 107 (LAM), 100-foot bluff with
fossiliferous concretions in clay quarry at end of Arroyo
Drive, San Diego; San Diego Formation, middle Pliocene.

Additional Occurrences in San Diego Fm. — C.A.S.
1402. L.A.M. 302. S.D. 3209.

Description. — Shell large, resembling Mytilus
coalingensis in general shape and trace of the lines of
growth. It differs from that species in that the valves are
less convex. Dimensions: length, 238 mm, width, 134 mm,
convexity near the unbonal area, 59 mm.

Remarks. — The presence of a large anterior
adductor impression on some of the present specimens is
similar to that on the type species of Crenomytilus.
Minute crenulations on the anterior ventral margin,
characteristic of Crenomytilus are not visible on our
specimens. Fine transverse rows of pustules on the ex-
terior of the anterior ventral end of M. coalingensis from
Pliocene strata in the San Joaquin Valley suggest that the
inner margin of the valves of that species is crenulated.

One specimen, referred to the new subspecies in
the collections of the California Academy of Sciences
and one in the Los Angeles County Museum, consist of
the beak and a portion of the umbonal area. A specimen
in the latter institution from Loc. 302 (LAM) is 48.5 mm
long and 33.6 mm in maximum width. A large anterior
muscle impression similar to that of M. coalingensis is
observable on these specimens.

One internal cast (““Steinkern”) from Kensington
Park in San Diego in the collections of the San Diego
Society of Natural History is 130 mm long and 73 mm
wide.

Woodring (142) mentioned the occurrence of casts

164

of a Mytilus in the Careaga beds and Foxen mudstone of
Pliocene age in the Santa Maria district, which he com-
pared with M. coalingensis but which he stated were
flatter than the valves of that species. His description of
these casts is reminiscent of the specimen from Loc.
3209 (SD).

The shell of Mytilus coalingensis sternbergi is
broader posteriorly and it is more curved toward the
beaks than is that of M. mathewsonii Gabb (143). The
anterior ventral margin of the new subspecies is more
curved than that of M. mathewsonii expansus Arnold
(144) and Mytilus kewi Nomland (145). Mytilus
schencki Hanna and Hertlein (146) is very much more
broadly expanded posteriorly.

The new subspecies, at the present time, is known
only from strata of middle Pliocene age in southern
California and northwestern Lower California. Mytilus
coalingensis is often encountered in beds of late Pliocene
age in San Joaquin Valley. It has been recorded from as
far north as the Sargent Oil Field (147) in Santa Clara
Co., and specimens referred doubtfully to Arnold’s species
have been reported (148) from the lower Merced Forma-
tion in San Mateo Co., California.

Specimens cited as “Mytilus coalingensis Arnold,
n. var.?” were reported by B. L. Clark (149) from beds
presumably of late Miocene age in Contra Costa Co.,
California.

GENUS AEIDIMYTILUS Olsson

Aeidimytilus Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 120,
March 10, 1961. 4

Type species (by original designation). — “Type
species Mytilus adamsiana Dunker.”

Range. — Middle Pliocene (and perhaps earlier) to
Recent. Recent in Temperate and tropical waters,
chiefly intertidal, reported to a depth of 55 to 91 meters
(30 to 50 fathoms).

Original description. — Shell small, mytiliform with
ribbed sculpture, usually divided, the ribs on the posterior-
dorsal side of the umbonal ridge much coarser. Ventral
side usually strongly impressed resulting in a_ high,
angular umbonal ridge and often a distorted appearance
to the whole shell. Adductor and pallial impressions
united, but smaller and narrower than in Scolimytilus.
(Olsson.)

Remarks. — Some of the west American Mytilidae
with small shells, especially those described as Mytilus
multiformis Carpenter and Mytilus adamsianus Dunker,
have been variously placed in the generic or subgeneric
categories of Brachidontes Swainson (150) and Hormomya
Morch (151). Recently Olsson, believing that these small
species combine some of the characters of both of the
foregoing categories, proposed a genus Scolimytilus (152)
and subgenus Aeidimytilus to include this group of species.
We assign generic status to Aeidimytilus with the type
species Mytilus adamsianus Dunker, at least until there
is more general agreement concerning the systematics of
these small mytilids.

The shells of this group usually develop a strongly
arched umbonal ridge, coarse sculpture on the dorsal area
and fine sculpture on the ventral area.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Aeidimytilus adamsianus Dunker
Plate 42, Figures 4, 5

Mytilus adamsianus Dunker, Proc. Zool. Soc. London for
1856, p. 360, issued May 8, 1857. — Reeve, Conch.
Icon., Vol. 10, Mytilus, sp. 55, pl. 11, fig. 55, 1858.
Panama. — I. S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 66, pl. 29, fig. 4, 1924. Santa
Barbara, California, to Panama and the Galapagos
Islands.

Mytilus stearnsi Pilsbry and Raymond, Nautilus, Vol. 12,
No. 6, p. 70, “plate 4, figs. 1, 2, 3,” October, 1898.
“San Diego,” California. [So far as we know the plate
here referred to was not published.] — Gardner, Jour.
Entom. Zool., Vol. 9, No. 3, p. 107, pl. 1, fig. 3, 1917.
Laguna Beach, California. — M. Smith, Panamic Marine
Shells (Trop. Photogr. Labor.: Winter Park, Florida),
p. 53, fig. 694, 1944. San Diego, California, to Chile.

Mytilus (Hormomya) adamsianus Dunker, J. Q. Burch,
Min. Conch. Club South. Calif., No. 36, p. 10, June,
1944. Cape San Lucas, Lower California, to Panama.

Mytilus (Hormomya) stearnsi Pilsbry and Raymond, T.
Burch, Min. Conch. Club South. Calif., No. 36, p. 16a,
fig., June, 1944. Punta Banda, Lower California,
Mexico.

Brachidontes (Hormomya) adamsianus Dunker, Hertlein
and Strong, Zoologica, Vol. 31, Pt. 2, p. 70, 1946.
Santa Barbara, California to Panama, and the Galapagos
Islands.

Hormomya adamsiana Dunker, Soot-Ryen, Allan Hancock
Pac. Exped., Vol. 20, No. 1, p. 37, pl. 3, fig. 11; text-
figs. 22, 25, 31, 1955. Santa Barbara, California, to
Ecuador. — Keen, Sea Shells of Tropical West America
(Stanford Univ. Press: Stanford, Calif.), p. 48, fig. 83,
1958. California to the Gulf of California and south to
the Galapagos Islands.

Scolimytilus (Aeidimytilus) adamsianus Dunker, Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 121, pl. 12, fig. 5; pl. 13,
figs. 4, 4a, 6, 1961. Lower California to Puerto Callo
(Jipijapa), Ecuador.

Type specimen. — Type lot in British Museum
(Natural History) (according to A. M. Keen, written
communication, April 22, 1965).

Type Locality. — ‘Hab. Ad Isthmum Panamense
(Cuming).”

Range. — Middle Pliocene to Recent. Recent from
Santa Barbara, California, to Puerto Callo (Jipijapa),
Ecuador, and the Galapagos Islands. Intertidal, usually
under rocks and stones. Reported to a depth of 55 to 91
meters (30 to 50 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305C.

Original description. — M. testa ovato-trigona,
utrinque obtuse carinata, solidula, costis mature bifidis
eleganter granosis sculpta, fusco-purpurascente et albida;
epidermide cornea vestita; umbonibus terminalibus;margine
crenato.

Testa parva 101lin. longa, 5 1/2 lin. alta, 4 1/2 lin. lata.
(Dunker.)

Remarks. — Three valves of this species, somewhat
eroded, are present in the collection from Loe. 305c
(LAM), from near the Mexican boundary. The largest one
is 18.9 mm long and 7.2 mm high (incomplete).

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Other workers have remarked upon the variability
in size and shape of a series of specimens of this species.
This is probably, in part, a result of the habitat under stones
and in crevices in rocks.

The beaks are small and nearly terminal and the
umbonal ridge is high. The ribbing and general shell
characters of the present valves agree exactly with speci-
mens from west Mexico and Central America. The ribs
on typical specimens of Aeidimytilus adamsianus are
coarse on the dorsal area, they increase posteriorly by
divarication or by addition. They are granulated as a result
of successive step-like resting stages. The ribs on the
ventral area are much finer. The dorsal area is brownish
purple, the ventral area yellowish white. Interiorly the
dorsal margin above the ligamental groove is strongly
crenulated. The external appearance of this shell is
remarkably similar to that of Septifer bifurcatus. Some
specimens are sculptured with fine ribs but such forms
agree in all other shell characters with the coarsely ribbed
ones.

It appears that this species reaches a greater size in
the northern part of its range. The largest specimens in
the collections of the California Academy of Sciences,
from three widely separated localities respectively are:
from San Diego, 22.5 mm long and 12.3 mm high; from
San Luis Gonzaga Bay, east coast of Lower California,
20.5 mm long; from Piedra Blanca, Costa Rica, 15 mm long.
We are uncertain of the identification of the species from
Costa Rica cited by Miller (153) under the name of
Mytilus adamsianus which was 53 mm long and 34 mm
wide.

We have not found any constant differences, other
than size, in shells from southern California and those
from Central America and the Galapagos Islands. This
leads us to include Mytilus stearnsi Pilsbry and Raymond
in the synonymy of A. adamsianus Olsson (1961) pub-
lished excellent illustrations of this species.

Some authors have believed that the nomenclature
of this species is involved with that of Mytilus multiformis
Carpenter. An illustration of a drawing of M. multiformis
by Carpenter, in the United States National Museum was
published by Olsson (1961, pl. 17, fig. 11). According to
Olsson, Carpenter’s manuscript sketches indicate ‘“‘a small,
short, fan-shaped shell with a large, smooth, nepionic area
followed by two or more sculptured areas set off sharply
from each other and the nepionic disk by resting lines; . .”
The shell characters of the species mentioned by Olsson
are distinct from those of typical A. adamsianus. Another
illustration of Carpenter’s species was published recently
by Brann (154.)

GENUS SEPTIFER RECLUZ

Septifer Récluz, Rev. Zool., Soc. Cuvierienne, Vol. 11,
p. 275, 1848. — Davies, Tertiary Faunas (Thomas
Murby and Co.: London), Vol. 1, p. 191, 1935. —
Lamy, Jour. de Conchyl., Vol. 80, No. 3, p. 239,
1936. — Iredale, Brit. Mus. (Nat. Hist.), Great Barrier
Reef. Exped., 1928-29, Sci. Repts., Vol. 5, No. 6,
Moll., Pt. 1, p. 424, 1939. Type as designated by
Stoliezka.

Type species (designated by Stoliczka, Mem. Geol.

Surv. India, Palaeont. Indica, Ser. 6, Cret. Fauna South

India, Vol. 3, pp. xxi, 366, 1871). — ‘“‘type, S. bilocularis,

165

Linn.” [= Mytilus bilocularis Linnaeus, Syst. Nat., ed. 10,
p. 705, 1758. “Habitat in O. Indico.” For synonymy
and a discussion see Brachidontes (Septifer) bilocularis
Linnaeus, Prashad, Siboga Exped., Monogr. 53, p. 69,
p. 2, figs. 21-24, 1932. East Indies. Widespread in the
Indopacific. |

Range. — Triassic (155) to Recent. Recent from
the intertidal zone to about 55 meters (30 fathoms).

Description. — Shell generally short, modioliform,
with a high umbonal angle, the external surface sculptured
with small radial riblets, often with bristles. Hinge and
posterior margins strongly crenulated, the short anterior
side with small dysodont teeth as in Brachidontes and
with a small deck or platform placed like a shelf in the
umbonal cavity below the beaks. (Olsson, A. A., Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), p. 122, 1961.)

Remarks. — The presence of an umbonal deck
interiorly readily serves to separate the shells of Septifer
from other members of the Mytilidae.

Five species of this genus have been reported from
strata of Tertiary age in California. One species is re-
ported here for the first time from the San Diego forma-
tion. Two, possibly three species, live in eastern Pacific
waters.

Lamy (1936) discussed Recent species of this genus
represented in the collections of the Museum of Natural
History in Paris.

Septifer bifurcatus Conrad
Plate 42, Figures 6, 12

M[ytilus]. bifurcatus Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 241, pl. 18, fig. 14,
1837. — Reeve, Conch. Icon., Vol. 10, Mytilus, sp. 41,
pl. 9, fig. 41, 1857.

Septifer bifurcatus Conrad, Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 119, 1903. Pleistocene and Recent. —
Gardner, Jour. Entomol. Zool., Vol. 9, No. 3, p. 107,
pl. 1, fig. 4, 1917. Laguna Beach, California, Recent.
— Grant and Gale, Mem. San Diego Soc. Nat. Hist.,
Vol. 1, p. 247, 1931. Pleistocene and Recent. —
Johnson and Snook, Seashore Animals of the Pacific
Coast (Macmillan Co.: New York), ed. 1935, p. 429,
fig. 389 (p. 430), 1935. ‘‘Northern California to the
Gulf of California.” — Nomura, Venus, Vol. 6, No. 4
p. 206 (in text), figs. 6a-d, 1936. California. —
Ricketts and Calvin, Between Pacific Tides (Stanford
Univ. Press: Stanford, Calif.), p. 99, pl. 22, fig. 3,
1939. Recent. — Soot-Ryen, Allan Hancock Pac.
Exped., Vol. 20, No. 1, p. 41, pl. 4, figs, 19, 20; text
fig. 33, 1955. Crescent City, California, to Cabo San
Lucas, Baja California, Recent.

Type specimen. — No. 57920, Academy of Natural
Sciences of Philadelphia (see A. M. Keen, Veliger, Vol. 8,
No. 3, p. 169, 1966).

Type locality. — “Inhabits, attached to rocks bare
at low water, in the Sandwich Islands, (Ouau, &).”
[Locality erroneous. This species is now believed to be a
member of the molluscan fauna of California. See note by
Henderson (Nautilus, Vol. 40, No. 3, p. 81, 1927) dealing
with Californian species erroneously described from
Hawaii by Conrad; also Keen, A. M., Min. Conch. Club
South. Calif., No. 36, p. 11, June, 1944.]

166

Range. — Middle Pliocene to Recent. Recent from
Crescent City, California, to Asuncion Island, and perhaps
to Cape San Lucas, Lower California, Mexico. Often at-
tached by byssus to underside of rocks; to 22 meters
(12 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305C.
S.D.S.C. 47.

Original description. — Shell narrowed, slightly
arcuate; anterior margin much flattened; ribs narrow,
prominent, bifurcated towards the base; colour dark
purple. Height, one and a half inches. (Conrad.)

Remarks. — Septifer bifurcatus is here reported for
the first time from strata of Pliocene age. One valve,
somewhat eroded, 18.2 mm long and 10.8 mm wide, is
present in the collection from Loc. 47 (San Diego State
Coll. Dept. Geol. Coll.) from Tijuana River Valley. One
valve, 10 mm long from near the Mexican boundary, is
present in the collections of the Los Angeles County
Museum. The largest Recent specimen in the collections
of the California Academy of Sciences collected by Henry
Hemphill at Loc. 5889 (CAS), San Diego, California, is
41.5 mm long and 18 mm high. Some large valves become
partially or almost entirely smooth after attaining a length
of about 25 mm. Shells similar to these with obsolete
radial sculpture were described as Septifer bifurcatus var.
obsoletus Dall. (156)

The species living in tropical and subtropical west
American waters formerly referred to Septifer cumingii
Récluz is now known as S. zeteki Hertlein and Strong
(157).

Records by Melvill and Standen (158) of S.
bifurcatus from the vicinity of the Falkland Islands are
undoubtedly referable to some other species. f

A species in Japan, formerly cited under the name
of Septifer bifurcatus Conrad, later described as S.
keeni by Nomura (159), is now referred to S. grayanus
Dunker (160) by Habe (161).

Seplifer margaritana Nomland (162), a species of
late Miocene age from about ten miles northeast of
Coalinga, California, was described as larger (52 mm long,
22 mm high) than S. bifurcatus, with more numerous
radiating riblets and with a more acute umbonal angula-
tion. We have examined a cast of the holotype which
reveals the shell characters mentioned by Nonland.

GENUS MODIOLUS LAMARCK

Volsella Scopoli, Introd. Hist. Nat., p. 397, 1777. Species
cited, ‘Mytilus Modiolus Linn. dente unico”; “Gula
Soricis Lister. dentibus 1-2).”; “Mytilus. L. Aber.
Adans. dentibus pluribus.”’ [According to E. Fischer-
Piette et al. (Jour. de Conchyl., Vol. 85, No. 4, p.
298, pl. 13, fig. 2, 1942) Gula soricis Lister is referable
to Brachidontes puniceus Gmelin. ] — Gray, Proc. Zool.
Soc. London for 1847, p. 198, 1847. Type, Mytilus
modiolus Linnaeus. — Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 248, 1931. Type as indicated
by Gray.

Modiolus Lamarck, Mem. Soc. Hist. Nat. Paris, p. 87,
1799. Sole species, “Mytilus modiolus.”’— Soot-Ryen,
Allan Hancock Pac. Exped., Vol. 20 No. 1, p. 56, 1955.
Type (according to Gray, 1847): Mytilus modiolus
Linnaeus. [Modiolus ruled a nomen conservadum and
placed on the official list of generic names in Zoology

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

with the type species, Mytilus modiolus Linnaeus, by
Internatl. Comm. Zool. Nomencel., Opinion 325,
signed May 8, 1954, published January 7, 1955.]

Modiola Lamarck, Syst. Anim. S. Vert., p. 113, 1801. Sole
species ““Modiola papuana, n. Argenv. t. 22, fig. C.
Encycl. t. 219, fig. 1. Chemn. 8, t. 85, f. 757. Vulg.
la moule des Papous.”” — Bucquoy, Dautzenberg, and
Dollfus, Moll. Mar. Roussillon, Vol. 2, Fase. 4, p. 150,
April, 1890. — Jukes-Brown, Proc. Malacol. Soc.
London, Vol. 6, No. 4, p. 221, March, 1905.

Eumodiola von Ihering, Proc. Malacol. Soc. London,
Vol. 4, p. 87, August, 1900. “Type, M. modiolus,
Linn.”

Type species (by monotypy and by absolute
tautonomy, and by ruling of the Internatl. Comm. Zool.
Nomencl., Opinion 325) — Mytilus modiolus Linnaeus
[Syst. Nat., ed. 10, p. 706, 1758. “Habitat in M.
Mediterraneo.” Ref. to Rumphius, Mus., t. 46, fig. B;
Argenville, Conch., t. 25, fig. C.; Bradl. Nat., t. 3, fig. 1.
Illustrated by Reeve, Conch. Icon., Vol. 10, Modiola,
pl. 1, fig. 2, 1858. ‘‘North Atlantic shores of Europe and
America.” — Clessin in Martini and Chemnitz, Conchyl.
Cab., Bd. 8, Abt. 3, Mytilidae, p. 92, pl. 5, fig. 3, 1889.
— Soot-Ryen, Allan Hancock Pac. Exped., Vol. 20, No. 1,
p. 66, text figs. 47, 48, 52, 1955].

Range. — Devonian to Recent, world wide, marine.
Recent from the intertidal zone to a depth of at least
183 meters (100 fathoms).

Description. Shell obliquely oblong, expanded
posteriorly and inflated along an oblique medial line
from the unbonal end to the posterior ventral margin;
dorsal margin curved or angulated; anterior end usually
produced beyond the umbones; exterior with a hairy
periostracum; hinge edentulous or often with a tooth-like
projection on anterior margin just below the anterior end
of the ligament.

Remarks. — A number of species of Modiolus have
been described from strata of Tertiary age in western
North America of which five have been recorded as oc-
curring in beds of Pliocene age. Eight Recent species
living in west American waters were assigned to this genus
by Soot-Ryen. These range from the intertidal zone toa
depth of 183 meters (100 fathoms) but most of them oc-
cur most abundantly in waters less than 92 meters (50
fathoms) in depth. Many of the species build “nests” of
sand and byssus threads.

Modiolus rectus Conrad
Plate 42, Figure 7

M [odiola]. recta Conrad, Jour. Acad. Nat. Sci. Philadel-
phia, Vol. ‘7, Pt. 2; p: 243; pl. 19) fig. 1) 183i
Dall, Proc. Calif. Acad. Sci., Vol. 5, p. 297, December,
1874. Also printed in advance, March 26, 1874. “Well
at San Diego,” Pliocene. — Dall, Proc. U. S. Nat. Mus.,
Vol. 1, p. 28, 1878. Well at San Diego. — Cooper,
Calif. State Min. Bur., Seventh Ann. Rept. California
State Mineral. for 1888, p. 251, 1888. “San Diego
well.” Also other localities. — Orcutt, cited by Ellis
in Ellis and Lee, U. S. G. S., Water Supply Paper 446,
p. 59,1919. Oreutt’s citation of Dall’s (1874) record.

Not Modiola recta Collignon, Ann. Géol. Serv. Mines de
Madagascar, Vol. 16, p. 16, pl. 2, figs. 5, 6, 1949.
Albian, Cretaceous, Madagascar.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Modiolus rectus Conrad, Arnold, Mem. Calif. Acad. Sci.,
Vol. 3, p. 120, 1903. “San Diego well (Cooper):
San Diego (Arnold).”’ “Pliocene.” — Arnold, U. S. G. S.,
Prof. Paper 47, p. 28, 1906. “San Diego formation”
at Pacific Beach, Pliocene. — J. P. Smith, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 3, p. 181, 1912. “San Diego-
Purisima”’. — J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4,
Vol. 9, No. 4, p. 151, 1919. “‘San Diego”, Pliocene. —
I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol.
Sci., Vol. 1., p. 68, 1924. “San Diego well; San
Diego well; San Diego”. — Waterfall, Univ. Calif.
Publ., Bull. Dept. Geol. Sci., Vol. 18, No. 3, opp. p.
78, 1929. “San Diego Pliocene.”

Volsella recta Conrad, Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 250, 1931. Cooper’s record
(1888), and Arnold’s records (1903), cited.

Type specimen. — Location of type specimen un-
known to the present authors.

Type locality. — “Inhabits sandy shores near Sta.
Barbara; rare.”

Range. — Late Miocene to Recent. Recent from
Vancouver Island, British Columbia, to Concepcion Bay,
east coast of Lower California; intertidal zone to about
46 meters (25 fathoms).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 957, 1178, 1186, 1400, 28880, 28886,
28889, 31320. L.A.M. 103, 305, 305A. S.D. 25, 29,
408. U.C.L.A. 302.

Original description. — Shell produced, smooth,
thin; anterior margin elevated; posterior side cuneiform;
colour brown, with a broad pale stripe extending from
the beak towards the posterior margin; within very
glossy and irridescent. Length, two inches. (Conrad.)

Remarks. — Most of the specimens representing
this species in collections from the San Diego Formation
are imperfectly preserved. The largest specimen, a right
valve from Loc. 305A (LAM), is 94 mm long and 42 mm
high. The extreme anterior end is lacking but the remainder
of the shell is comparable to Recent specimens of
Modiolus rectus which lives in adjacent waters at the
present time. A specimen collected by R. E. Lando, from
Loc. 31320 (CAS), 68.8 mm long, also lacks the anterior
portion of the shell.

Modiolus flabellatus Gould (163), considered by
some authors to be a more alate form of M. rectus was
placed in the synonymy of the latter species by Soot-Ryen.

Modiolus directus Dall (164), described from the
Empire Formation of Pliocene age in Oregon, was said to
differ from M. rectus in that “the anterior end of M.
directus is proportionally much shorter than in rectus, and
the posterior end still more so; the fossil is not alate
above like the variety flabellatus Gould, and it is also
more arcuate than rectus.’’ Considerable variation exists
in a series of specimens of M. rectus, Recent as well as
fossil. Authors vary in their opinions concerning the
taxonomic status of M. directus. Arnold and Hannibal
(165), Howe (166) (questionably), and Grant and Gale,
all placed it in the synonymy of M. rectus; but Etherington
(167), Weaver (168), and more recently Moore, (169)
treated it as a distinct species of Miocene age.

Modiolus rectus occurs rather commonly at various
localities in California in beds of Pliocene age. At the
present time this mollusk lives on a muddy bottom with
the anterior portion embedded in a nest in the mud but

167

with the posterior portion of the shell exposed above the
surface of the bottom. Specimens are often found which
are 120 mm to 130 mm in length but huge forms are
reported to attain a length of 230 mm.

Modiolus sacculifer Berry
Plate 41, Figures 2-4

Vosella sacculifer S. S. Berry, Trans. San Diego Soc. Nat.
Hist., Vol. 11, No. 16, p. 407, pl. 28, figs. 1, 2, text
fig. 1, September 1, 1953.

Modiolus sacculifer Berry, Soot-Ryen, Allen Hancock Pac.
Exped., Vol. 20, No. 1, p. 65, text-figs. 57a-b, 58,
November 10, 1958. Type locality cited. Range,
“Bechers Bay, California, south to San Clemente Island,
California.”’ Recent.

Type specimen. — No. 7853, Stanford University,
Department of Geology.

Type locality. — “San Pedro harbor, California.”

Range. — Middle Pliocene to Recent. Recent from
Monterey to Long Beach, also Bechers Bay, Santa Rosa
Island, and San Clemente Island, California, from low
tidal zone to 102 meters (56 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A.

Original description. — Shell of but moderate size
for the genus, in outline broadly almond-shaped; highest
at about the mid-point, thin, smooth, moderately in-
flated; hinge-line nearly straight to very slightly arcuate.
Valves well rounded behind, more or less distinctly
swollen ventrally in the byssal region and produced
abruptly into a small obtuse lobe-like flare or pocket just
under the umbones, the rounded angle of this pocket
forming the anterior end of the shell; postero-dorsal area
subalate, its angle obtuse. Hinge toothless except for a
short, sharply conical, posteriorly directed process set
off by a notch at the anterior insertion of the ligament.
Periostracum light to deep brown (near Buckthorn Brown
to Mummy Brown), smooth, polished, under the more or
less dehiscent traces of some fairly considerable posterior
shagginess. (Berry.)

Measurements. — holotype, maximum length, 38.0
mm, maximum altitude, 20.0 mm, diameter, 15.8 mm.
(Berry.)

Remarks. — Several single valves, the largest 52.2 mm
long, in the collections of the Los Angeles County Museum
are identical with Recent specimens of Modiolus sacculifer.
Many fragments consisting of the anterior ends of valves
also are probably referable to this species.

A large Recent specimen of this species from San
Pedro, California, is 57.5 mm long (beak to base),
height 34 mm, convexity (both valves together), 26.4mm.

The shell of M. sacculifer is readily separable from
that of Modiolus carpenteri Soot-Ryen (170), a new
name for Modiola fornicata Carpenter (171), in that the
lobe-like anterior end extends beyond the beaks whereas
in Soot-Ryen’s species it does not.

Modiolus inflatus Dall (172), described from beds of
Pliocene age at Coos Bay, Oregon, was later named M.
trinominatus by Hanna (173). Dall compared his species
with M. fornicatus [= M. carpenteri|. Recent specimens
of M. sacculifer agree with Dall’s illustration of M.
inflatus except that the anterior end of the fossil is
broader and the lobe-like character of the anterior ex-
tremity is not clearly observable. Dall mentioned that the

168

anterior end of M. inflatus is narrow and rounded.

Through the courtesy of Dr. G. A. Cooper, United
States National Museum, we have had the opportunity to
examine the type specimens of that species. It appears
obvious that the preservation of the holotype is not per-
fect. The general outline of a virtual paratype ac-
companying the holotype agrees well with M. sacculifer
but the anterior end of this specimen also is imperfect. If
perfect specimens of the Oregon fossils are found showing
a lobe-like, pouting anterior end, it is not unlikely that the
earliest name available for the Recent species named M.
sacculifer may be M. trinominatus.

GENUS GREGARIELLA MONTEROSATO

Gregariella Monterosato, Nomenclatura Generica e Speci-
fica di alcune Conchiglie Mediterranee, p. 11, 1884.
Species Cited: “‘G. sulcata, Risso (Modiolus sulcatus) —
1826, p. 324 (Alpi Marit.)’’ with synonyms, and “G.
gibberula, Caillaud (Modiola) — Catal. ecc. Nantes
1865, p. 109, t. 4, 9-12 (Loire Inférieure)” with
synonyms. — Soot-Ryen, Allan Hancock Pac. Exped.,
Vol. 20, No. 1, p. 76,1955. Type of genus: Modiolus
sulcatus Risso 1826 (non Lamarck 1805, 1819). —
Olsson, Mollusks of the Tropical eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), p. 128, 1961.
Type species as designated by Crosse.

Botulina Dall, U.S. Nat. Mus., Bull. 37, p. 38, 1889.
Sole species, “M. opifex Say.” “Hatteras.”

Trichomusculus Iredale, Proc. Linn. Soc. New South
Wales, Vol. 49, Pt. 3, p. 196, October 24, 1924. “I
propose the new genus Trichomusculus, with barbatus
as type.” P. 181, “for Lithodomus barbatus Reeve.”

Tibialectus Iredale, Brit. Mus. (Nat. Hist.) Great Barrier
Reef Exped. 1928-29, Sci. Repts., Vol. 5, No. 6,
Moll., Pt. 1, p. 424, February 25, 1939. “Type: T.
otteri, sp. nov.”’, p. 424, pl. 6, fig. 24.

Type species (designated by Cross, Jour. de Conchyl.,
Vol. 33 (Ser. 3, Vol. 25), No. 2, p. 140, 1885). — “type:
Modiolus sulcatus, Risso).’”’ [Modiolus sulcatus Risso,
Hist. Nat. Europe Mérid., Vol. 4, p. 324, 1826 (not
Modiolus sulcatus Lamarck, 1805). ‘“Sej. Régions
profundes. App. Printemps.” [Illustrated by Clessin,
Conchyl. — Cab. von Martini und Chemnitz, ed. 2, Bd. 8,
No. 3, p. 138, pl. 36, fig. 5 (as Modiola sulcata). —
Bucquoy, Dautzenberg, and Dollfus, Moll. Mar. Roussillon,
Vol. 2, Fasc. 4 (Pelecypoda, Fasc. 17), p. 170, pl. 29, figs.
29, 30, 31, 32, 1890 (as Modiolaria sulcata). See also
Reeve, Conch. Icon., Vol. 10, Modiola, sp. 46, pl. 8,
fig. 46, 1857 (as Modiola petagnae Scacchi). |

Range. — Miocene to Recent. Recent in from 4 to
91 meters (2 to 50 fathoms).

Description. — Shell modioliform, valves convex
often angulated from the umbo to the posterior margin,
beaks nearly terminal, hinge line short, posterior end
attenuated; sculpture similar to that of Musculus, radial
riblets divaricating along the medial umbonal slope, but an
anterior median ventral area smooth, decussated sculpture
sometimes formed when the radial riblets are crossed by
thickened concentric lines of growth; posterior area
covered with a brown periostracum bearing hair-like
filaments and these may continue anteriorly along the
central angulation; inner margin finely crenulated cor-
responding to the ends of the radial riblets; resilifer

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

narrow, often with dysodont teeth; anterior adductor
large, oval. Usually burrowing forms. (Adapted chiefly
from Olsson, 1961.)

Remarks. — This is the first record of Gregariella
from the Pliocene of California. Three species now live
in west American waters. Others live in the Caribbean,
Mediterranean, and Indo-Pacific regions.

Gregariella chenui Récluz
Plate 41, Figures 1, 5; Plate 42, Figures 1, 8

Mytilus (modiola) chenui Récluz, Rev.
Cuvierienne, Vol. 5, p. 306, 1842.

Mytilus chenuanus d’orbigny, Voy. Amér. Mérid., Vol. 5,
Moll., p. 649, pl. 85, figs. 14-16, 1846. “Elle a été
recueillie au Brésil par M. Fontaine; elle se tient entre
les rochers.”’ [On explanation to plates, figs. 14-16 on
plate 85 are referred to as Mytilus fontaineanus. |

Mytilus fontaineanus d’Orbigny, Voy. Amér. Meérid., Vol.
5, Moll., p. 710, pl. 85, figs. 14-16, 1846.

Mod. (Gregariella) chenui Recluz, Lamy, Jour. de
Conchyl., Vol. 81, No. 1, p. 40, 1937. “Bahia.”

Gregariella chenui Récluz, Soot-Ryen, Allan Hancock
Pac. Exped., Vol. 20, No. 1, p. 78, pl. 8, fig. 40;
text-fig. 65, 1955. Monterey, California, south to
Bahia de la Independencia, Peru.

ee opifex of west American authors, not of Say,
1825.

Type specimen. — Location unknown to the present
authors.

Type locality. — ‘Hab. les cdtes du Brésil, province
de Bahia.”

Range. — Middle Pliocene to Recent. Recent from
Monterey Bay, California to Bahia de la Independencia,
Peru. (Soot-Ryen.) Also Brasil and Caribbean region, in
from 2 to 91 meters (4 to 50 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305C.

Original description. — Coquille transverse, ovale,
renflée, mince, marquée d’un angle obtus des sommets au
bord posteriéur et plane en dessus, arrondie, étroite et
plus courte antérieurement qu’au coté posterieur, lequel
est plus retréci et presque anguleux. Sommets petits,
saillants, obtusément arrondis, placés tres-pres du bord
antérieur et décortiques; l’extérieur est sculpté de trés
petits sillons longitudinaux, partant des crochets et
rayonnant vers la base des valves: les sillons sont finement
striés en dedans et ont un aspect presque onduleux; les
antérieurs sont arqués et obliquent fortement en avant;
les postérieurs ont une direction antérieure plus droit dans
leur cours. Ces sillons et ces stries sont effacés sur le
tiers antérieur des valves ou a peine apparents, et a cette
place regne une dépression qui part des crochets, ou elle
est peu sensible et se continue en augmentant graduelle-
ment d’intensité jusqu’A la base des valves, qu’elle
rétrécit légerement dans leur longeur. La couleur de
cette coquille est roussatre, peinte longitudinalement
d’une large fascie marron sur la partie deprimee et lisse.
Toute la portion postérieure est couverte de poils
jaunatres, comme agglutinés entre eux, et dont les
postérieurs sont disposés en trois ou quatre filaments
roides, velus et saillants d’un a deux millimetres. Intérieur
nacré et légerement irisé. Charniere formée d’une série
de denticules ou crenélures qui, tres-saillantes antérieure-
ment, se continuent sur toute la région supérieure des

Zool., Soc.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

valves, et viennent finir sur le milieu du cOté postérieur,
en s’affaiblissant graduellement dans leur cours. — Larg.
16, diam. 10, convex. 10 mill. (Récluz.) [A description
in the Latin language also is given by Récluz. ]

Remarks. — One right valve here referred to
Gregariella chenui, 4.6 mm long and 2.5 mm high, is
present in the collections of the Los Angeles County
Museum from near the Mexican boundary. This is the
first record of this species in the San Diego Formation.

This valve agrees in all particulars with specimens
dredged off Catalina Island, California, in 55-90 meters
(30-50 fathoms). The radial sculpture on both the fossil
and on the Recent shells is well developed and beaded
posteriorly where crossed by coarse concentric lines of
growth. The largest valve in the lot from off Catalina
Island is 9.4 mm long and 4.6 mm high.

This species has been cited under the names of
Botulina or Gregariella opifex Say and B. denticulata
Dall. Soot-Ryen discussed the problems connected with
the correct name for this species. He accepted Gregariella
chenui as the earliest name applicable to both the east
and west American species of Gregariella.

The species described as Modiolus opifex Say (174)
originally came “Amongst a number of marine shells
from the island of Minorca,” on “a single valve of the
Pecten nodosus, Linn.’’, “attached by a broad base to the
surface of the Pecten.” The dimensions were given as
“Breadth nearly half an inch; length more than one-fifth
of an inch.” The illustrations depict a weakly sculptured
shell similar in shape to a Gregariella.

There appears to be no reason to doubt the locality
given for this species by Say. Until evidence can be pre-
sented which definitely places Say’s species as living in
east American waters, it seems best to follow Soot-Ryen’s
decision to recognize Mytilus chenui Recluz as the
earliest name available applicable to the east American
species of Gregariella formerly cited as G. opifex. We have
not had specimens of G. chenui from Brazil available for
comparison but we have no good reason to question Soot-
Ryen’s identification of west American forms with that
species. The reported range, however, is very great, from
Brazil to Monterey, California. Olsson (1961, p. 129)
mentioned that he did not find it in the Panamic region.
Confirmation of the identity of the Brazilian species with

the one from California is desirable.
Gregariella denticulata Dall (175) has been con-

fused with G. chenui but Keen (176) recently clarified
this matter and illustrated the type specimen. She
described it as a pearly white shell covered with a brown
to black, bearded periostracum.

The sculpture on the shell of G. chenui is much
coarser, the posterior end more rounded and the umbonal
slope is less angulated than that of G. coaretata Dunker in
Carpenter (177). Specimens of G. coarctata which we
have seen are larger than those of G. chenui.

Odhner (178) reported a species under the name of
“Modiolaria (Gregariella) opifex Philippi” from Mas
Atierra, west of Chile, in 35 to 40 meters. The maximum
length of the specimens was 10 mm. We have not seen
specimens from that area.

GENUS LITHOPHAGA RODING IN BOLTEN

Lithophaga Roding in Bolten, Mus. Boltenianum, p. 156,

169

1798. Species cited, “L. Mytuloides. Der Muschelartige
Steinbohrer. Gmel. Mytilus lithophagus. sp. 6.
Chemn. 8. t. 82. f. 729. 730.” — Iredale, Brit. Mus.
(Nat. Hist.), Great Barrier Reef Exped. 1928-29, Sci.
Repts., Vol. 5, No. 6, Moll., Pt. 1, p. 416, February 25,
1939. “Haplotype: L. mytuloides = M. lithophagus
Gmelin.” — Cox, Mem. Geol. Surv. India, Palaeont.
Indica, Ser. 9, Vol. 3, Pt. 3, p. 73, 1940. “Genotype.
— Mytilus lithophagus Linné (1758, p. 705)”. —
Gardner, Geol. Soc. Amer., Mem. 11, p. 57, 1945.
“Type, by monotypy: Mytilus lithophagus Linnaeus
= Lithodomus dactylus Sowerby.” — Soot-Ryen, Allan
Hancock Pac. Exped., Vol. 20, No. 1, p. 91, 1955.
“Type of genus: Lithophaga mytuloides Réding
1798 = Mytilus lithopagus Linné 1780.”

Lithophagus Megerle von Mihlfeld, Gesell. Naturfor.
Freunde zu Berlin, Vol. 6, Abt. 1, p. 69, 1811.
Species cited, “Lithophagus communis.”

Lithodomus Cuvier, Le Regne Anim., Vol. 2, p. 471,
1817 [December, 1816, according to Iredale, 1939].
Type designated by Sowerby (Gen. Rec. Foss. Shells,
Vol. 2, No. 23, Lithophaga, 1824): “The type of this
genus is the Mytilus Lithophagus of authors, which is
very common in the Mediterranean, West Indies, and
in all Coral rocks.’ Also by Herrmannsen, Indic.
Malacozoor., Vol. 1, p. 611, 1847): “Typus: Mytilus
lithophagus Linn.”

Lithotornus Cuv., Schweigger, Handbuch Naturgesch, p.
712, 1820. Error for Lithodomus Cuvier, corrected
on p. 776.

Type species (by virtual monotypy and by sub-
sequent designation, Dall, Jour. Conch., Vol. 11, No. 10,
p. 296, April, 1906). — Mytilus lithophagus Gmelin [=
Mytilus lithophagus Linnaeus, Syst. Nat., ed. 10, p. 705,
1758. “Habitat in O. Indico, Europaeo, Mediterraneo,
penetrans. & exedens Marmora, Corallia &.” Ref. to
“List. angl. 235. t. 8. f. 37”, “Rumph. mus. t. 46. f. F.
Pholas”’; “‘Gault. test. t. 90. f. D.”’, and others. Illustrated
by Chemnitz, Syst. Conch. -Cab., Vol. 8, 1785, p. 147,
pl. 82, figs, 729, 730. Also by Reeve, Conch. Icon., Vol.
10, Lithodomus, species 9, pl. 2, fig. 9, 1857, and by
Bucquoy, Dautzenberg, and Dollfus, Moll. Mar. Roussillon,
Tome 2, p. 160, Fasc. 4 (Pelecypoda, Fase. 17), p. 160,
pl. 28, figs. 12-15, 1890. Fora discussion of this species,
see Dodge, H., Bull. Amer. Mus. Hat. Hist., Vol. 100,
Art. 1, p. 208, 1952].

Range. — ? Late Paleozoic. Late Triassic (Frech)
to Recent. Recent world-wide in warm temperate and
especially in tropical and subtropical waters, from inter-
tidal zone to 91 meters (50 fathoms), rarely deeper.
Lithophaga aristata reported from a depth of 302 meters
(165 fathoms) by Soot-Ryen (1955, p. 98).

Description. — Shell sub-cylindrical, strongly in-
flated, elongate, not very oblique; umbones obtusely
rounded, placed near or at the anterior end. Anterior end
evenly rounded and inflated, posterior end rounded or
tapering. Valve margins closed, without a byssal gape.
Dysodont teeth absent. Ligament elongate, narrow, sub-
external, supported, as in Modiolus and Mytilus, by an
internal ridge which continues the antero-dorsal margin.
Anterior adductor rather ventrally placed, nearly as large
as the posterior one. Surface either smooth, or with fine
transverse striations, or with coarse transverse ridges con-
fined to the posterior end, or with radial ribs at the post-

170

erior end; or, in some species, partly coated with a
calcareous incrustation. Habitat rock-boring. (Cox, 1940.)

Remarks. — Lithophaga is represented by but few
species in beds of Tertiary age in California. Two species
have been described from the Eocene, one unidentified
form in the early Miocene and one species in the Pliocene.
Fragments and imperfectly preserved specimens are here
reported for the first time from the San Diego Formation.
Nine species and subspecies, arranged in six subgenera, are
recognized by Soot-Ryen as occurring in waters between
southern California and Chile. Only one reaches Cali-
fornian waters.

This genus is believed to be derived from Modiolus.
The various species bore into rocks as well as into corals
and thick mollusean shells. They accomplish this process
by means of a specially secreted acid. This boring process
has been discussed by Kuhnelt (179) and by Hodgkin (180).
The boring activities of Lithophaga and other animals in
coral reefs were described by Otter (181). Verrill (182)
mentioned that the shells of nearly all mollusks that bore
into rocks are luminous or phosphorescent.

Lithophaga sp.

Occurrence in San Diego Fm. — L.A.M. 107, P.87.

Remarks. — Two casts from India and Upas streets,
San Diego, the larger one 24.6 mm long, are present in
the collections of the Los Angeles County Museum.
Unornamented fragments of the interior layers of the shell
also are present. The general shape of the casts cor-
responds fairly well with Recent specimens of Lithophaga
plumula kelseyi Hertlein and Strong (183), of comparable
size, living in adjacent waters. This form was referred by
Soot-Ryen (184) to L. subula Reeve (185), a species
described without information concerning the locality
from which it came. The imperfect preservation of the
fossils makes positive identification of them with L. p.
kelseyi a matter of uncertainty. Willett (186) reported
what may be this form from beds of late Pliocene age at
Fifth and Hope streets in Los Angeles.

Two fragments, casts retaining occasional patches
of the internal portion of the shell material, are present
from Loc. 107 (LAM). The larger one, an anterior
portion of the specimen is 29.6 mm long and the maxi-
mum convexity (both valves together), is 18.6 mm. The
size and general shape of the two fragments bear a
resemblance to Lithophaga attenuata Deshayes (187)
but because of the incomplete state and lack of shell
material we hesitate to refer these casts to any named
species.

Four casts and impressions of a Lithophaga, re-
taining some of the shell material, are present in the col-
lections of the Los Angeles County Museum but without
information as to the locality from which they came.
The matrix is not unlike that from Loe. 107 (LAM).
The largest impression of a valve is about 55 mm long
and 15 mm high. The shape is similar to that of L.
attenuata but the preservation is too imperfect to permit
identification of the species with certainty.

Berry proposed the name Lithophaga (Labis) at-
tenuata rogersi (188) for a form living in the Gulf of
California.

GENUS CRENELLA BROWN

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Crenella T. Brown, Illustr. Conch. Great. Brit. and Ireland
(189), p. 1, pl. 31, figs. 12-14, 1827. Species cited,
“Crenella elliptica Brown” in the synonymy of which
was “Mytilus decussatus, Laskey in Wern. Mem. 1, p.
394, pl. 8, fig. 17. — Mont. Test. Brit. Sup. p. 69.” —
Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p.
801, 1898. “Type Mytilus decussatus Montagu,
1808.’ — Eames, Philos. Trans. Roy. Soc. London,
Ser. B, Biol. Sci., No. 627, Vol. 235, p. 370, June 26,
1951. “Type species. Crenella elliptica (Leach MS.)
Brown, Recent = Mytilus decussatus Montagu, in
Macegillivray; monotypy, and Stoliczka, 1871.” —
Olsson and Harbison, Acad. Nat. Sci. Philadelphia,
Monogr. No. 8, p. 63, 1953. “Type by monotypy;
Mytilus decussatus Montagu.”

Type species (by subsequent designation, Stoliczka,
Mem. Geol. Surv. India, Palaeont. Indica, Ser. 6, Vol. 3,
p. XXI, 1871). — “Typical species. Cr. decussata, Montg.”
[= Mytilus decussatus Montagu, Test. Brit., Suppl., Vol. 3,
p. 69, 1808. “in sand on the Scottish coast.” Ref. to
“Chem. Conch. VIII. t. 85. f. 761?” Also illustrated by
Clessin, Martini-Chemnitz Conchyl. — Cab., ed. 2, Bd. 8,
Abt. 3, Mytilacea, p. 149, pl. 34, figs., 13-14, 1889. —
Tebble, British Bivalve Seashells [British Museum (Nat.
Hist.)], p. 48, text fig. 19a, 1966. }

Range. — Late Cretaceous to Recent.
from 2 to 4188 meters (2290 fathoms).

Description. — Shell small or medium sized, some-
times minute, obliquely-ovate, convex, with small, in-
curved, prosogyrate beaks. Prodissoconch usually well
preserved, smooth. Interior often thickened, pearly, the
outer surface covered by a thin, closely adhering epider-
mis. Hinge mytiloid, with small tooth-like knobs on the
anterior margin bordered on the posterior side by a deep,
furrow-like pit for the attachment of the ligament which
is wholly internal. External sculpture composed of fine
radials crossed or decussated by concentrics, often divari-
cated along the middle line of the umbonal slope. Inner
margin crenulated by the ends of the external riblets all
around, sometimes extending into the hinge itself, pro-
ducing a pseudotaxodont pattern. (Olsson and Harbison.)

Remarks. — Some authors have placed in the
synonymy of Crenella the genera Stalagmium Conrad,
Hippagus Lea, and Myoparo Lea, but Eames presented
reasons for excluding these from Brown’s genus. Nucu-
locardia d’Orbigny however, is generally relegated to the
synonymy of Crenella.

The shells of Crenella are small and it is often dif-
ficult to separate the species. Most of the Recent species
of this genus live in cool waters but a few occur in tropical
waters.

Gray , 1840, placed this genus in a family Crenellidae.

Some of the species of Cretaceous and Tertiary age
described under the genus Crenella are referable to
Arcoperna Conrad (190). According to van de Poel (191)
a shell character of Arcoperna which may be relied upon
to separate it from Crenella is the presence of a narrow,
smooth band which extends from the beak to the anterior
ventral margin.

The shells of species assigned to the genus Arvella
Bartsch (192) resemble Musculus Roding in Bolten in
outline and have much broader, coarser, radial ribs than
those of Crenella. Botulopsis Reis (Geogn. Jahreshefte,
Bd. 39, p. 124, 1926), described from strata of Triassic

Recent in

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

age, is believed to be a member of the Crenella group.

Crenella inflata Carpenter
Plate 41, Figure 11

2Crenella inflata Carpenter, Ann. Mag. Nat. Hist., Ser. 3,
Vol. 13, p. 313, April, 1864. Reprint in Smithsonian
Mise. Coll., No. 252, p. 211, 1872. — K.V.W. Palmer,
Bull. Amer. Paleo., Vol. 46, No. 211, p. 302, 1963.
Cape St. Lucas (Xantus). ‘The type of C. inflata has
not been found nor has it been illustrated.”

Not Crenella inflata Miiller, Holzapfel, Palaeontographica,
Bd. 35 (Moll. Aachener Kreide, Abt. 2), p. 220, pl. 25,
figs. 17, 18, 1889. [This species was originally
described as Mytilus inflatus Miller, Monogr. der
Petrefacten der Aachener Kreideformation (Bonn),
p. 35, pl. 2, figs. 9, 9a, 1847. ‘im Griinsand bei Vaels,
als steinkern auch am Schindanger.” |

Crenella divaricata d’Orbigny, Hertlein and Strong, Zoo-
logica, Vol. 31, Pt. 2, p. 75, pl. 1, figs. 12, 13, 1946.
“Guadalupe Island, Off Lower California, Mexico, and
the Gulf of California to Ecuador.’’ — Soot-Ryen,
Allan Hancock Pac. Exped., Vol. 20, No. 1, p. 80, pl. 8,
figs. 42, 44, 1955. Huntington Beach and San Miguel
Island, California, to Callao, Peru. — Keen, Sea Shells
of Tropical West America (Stanford Univ. Press:
Stanford, California), p. 50, fig. 88, 1958. Southern
California to the Gulf of California and south to Peru.

Not Nuculocardia divaricata d’Orbigny, 1842. [Referred
to the genus Crenella by later authors. |

Type specimen. — A specimen ‘‘marked as Carpen-
ter’s type, bearing USNM Catalog Number 3998” is in the
collection of the United States National Museum (J.
Rosewater, written communication, November 4, 1964).
Keen (written communication, October 20, 1964) men-
tioned that ‘‘One slide is at the B. M. labelled by Carpenter,
from Cape San Lucas. The specimen is missing, ap-
parently broken.”

Type locality. — ‘Cape St. Lucas,” Lower Cali-
fornia, Mexico.

Range. — Middle Pliocene to Recent. Recent from
Huntington Beach and San Miguel Island, California (Soot-
Ryen) to the Gulf of California and south to Callao, Peru,
in 4 to 91 meters (2 to 50 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A,
305C.

Original description. — ?C. testa valde inflata,
minuta, albida, subrhomboideo-orbiculari; diagonaliter
parum producta; marginibus subquadrangulatim rotun-
datis; umbonibus prominentibus, valde antice intortis;
tota superficie ut in C. decussata sculpta, costulis crebris
radiantibus aequidistantibus, hic et illic aliis intercalatis;
lirulis concentricis decussantibus: intus margine dorsali
brevissimo, arcuato, dentato; ligamento curtissimo, in
fossa omnino interna, celata, lamina definiente, sito;
lamina cardinali sub umbonibus intus porrecta, dentibus
validis instructa; marginibus internis omnino crenatis;
cicatr. adduct. subaequalibus, ventraliter sitis. Long. .1,
lat. .12, alt. .09 poll. (Carpenter.)

Remarks. — Three specimens in the collections of
the Los Angeles Museum, the largest 3 mm long and
2.3 mm wide, are here referred to the form described by
Carpenter as “‘?Crenella inflata.” This identification is
based upon identity with specimens identified by A. M.

171

Strong as C. inflata from Cape San Lucas, the type locality
of that form.

Some authors have considered C. inflata to be a
synonym of C. divaricata d’Orbigny (193), originally
described from Cuba, which they believed also lives in
tropical west American waters.

We have not seen specimens from Cuba but we have
based our conception of that species upon d’Orbigny’s
original description and figures, as well as upon those of
other authors, which agree favorably with d’Orbigny’s
delineations.

Some Recent specimens from west American waters
which have generally been considered to represent
d’Orbigny’s species, possess finer radial ribbing, less
prominent concentric sculpture, and the umbos are less
projecting and inflated than that of the fossil forms here
referred to as C. inflata. Keen (1958, p. 50) considered
C. inflata Carpenter and C. ecuadoriana Pilsbry and
Olsson to be synonyms of C. divaricata,

Olsson (194), however, recently stated that ‘the
Caribbean shell is thinner, less symmetrical in shape,
usually with a larger, more conspicuous prodissoconch
and with weaker sculpture.” He assigned the tropical
west American species referred to C. divaricata by
Hertlein and Strong, to C. ecuadoriana Pilsbry and Olsson
(195), a species described from strata of Pliocene age in
Ecuador. Olsson recently described a subspecies, C.
ecuadoriana santiaga (196) from strata of Miocene age in
Ecuador. He also described C. caudiva (197), a Recent
species from Ecuador, which he stated is ‘‘Distinguished
easily from C. ecuadoriana by its unsymmetrical valves
and subrhombic shape.”

The fossils from the San Diego Formation bear a
great similarity to some forms of C. decussata. Some
authors have considered the west American C. “‘divaricata”
to be a southern race of C. decussata as mentioned by
Burch (198) who discussed the two species. The fossil
specimens differ from typical C. decussata from England
in the more elongately ovate shape, greater inflation, more
projecting umbos and in the narrower interspaces between
the radial ribs. The comparatively coarse ribbing on the
fossil specimens resembles that of C. decussata more than it
does the “‘Crenella divaricata” of west American authors.
However, the relationship of the various west American
species of Crenella is unknown and provisionally we leave
Carpenter’s C. inflata the rank of species.

ORDER ISODONTIDA DALL
SUPERFAMILY PECTINACEA RAFINESQUE (199)

Newell (200) gave a detailed discussion of the
American Paleozoic groups of this superfamily.

FAMILY PECTINIDAE RAFINESQUE (201)

Shell usually of medium to large size, equivalve or
inequivalve, orbicular to subtriangular, equilateral or
nearly so; the valves may be alike in convexity and
sculpture or they may be quite different, often slightly
inflated or with one valve more inflated than the other,
and may be thick or thin; monomyarian, with a single
adductor muscle impression slightly posterior of the mid-
dle; beaks and umbones placed medially, usually with two
triangular wings (auricles or ears), one on either side of the

172

umbo, the anterior one in the right valve usually with a
distinct byssal sinus but this is almost lacking in some
groups; surface smooth or with radial ribs or folds which
corrugate the shell, sometimes with concentric lamellae;
interior may be smooth or may bear radial riblets, hinge
line straight, edentulous, taxodont in the very young but
obsolete later, vertically striated in some groups; ligament
in a central, triangular pit below the beaks, often with
one or more oblique ridges of varying size diverging from
it on either side; surface of upper (left) valve or both,
often colored. (Adapted from Dall, Bartsch, and Rehder,
Bernice P. Bishop Mus., Bull. 153, 1938, and Olsson,
Mollusks of the tropical eastern Pacific, Paleo. Res. Inst.:
Ithaca, New York, 1961.) Triassic to Recent, world-wide.

Remarks. — The members of this family have a wide
distribution both geographically and geologically. Some
swim about freely, others are attached by a byssus and
rarely (as in Hinnites) they become sessile and irregular
in form. Most of the large, coarse, thick shelled forms live
in shallow temperate and tropical waters, but thin shelled
usually small deep-sea forms occur in depths of at least
4504 meters (2463 fathoms).

Several thousand species of pectens have been
described as fossils. About 350 to 400 species are now
living in the seas, the greater number in Indo-Pacific
waters. The largest forms, with the exception of species
of Patinopecten, live in tropical marine waters. The
valves of many species inhabiting temperate waters tend
to be less convex and the ribs more rounded in the
northern part of their range.

In some areas pectens live in great numbers. Verco
(202) mentioned that off Point Marsden, Australia, at a
depth of 33 meters (18 fathoms), for miles the bottom of
the sea was covered with scallop shells.

The shape and sculpture of the shells of pectens,
usually differing in detail on the two valves, are often
quite constant, and, as mentioned by Kautsky (203),
species may often be recognized from fragments.
Jaworski (204) reported the observation that when riblets
arise in the interspaces between the ribs of “Vola”
[Pecten s. s.] they always appear first on the left valve.
Dall (1898, pp. 692, 693) pointed out that when ribbing
tends to become obsolete, the radial sculpture is retained
on the left valve after the right valve has become nearly
smooth, Furthermore, that the right anterior ear usually,
is the last to lose its radial sculpture.

An interesting characteristic of the sculpture of
these bivalves is that rarely, if ever, do they possess con-
centric ribbing although some species such as Chlamys
(Swiftopecten) swiftii Bernardi and C. condylomatus Dall
have concentric thickening and undulations or “‘ledging”
(205) of the shell and others have coarse annular growth
lamellae such as are present in the subgenus Camptochlamys
Arkell. The effect of environment or other causes on the
shell was well expressed by Arkell (206) who stated, “‘The
Pectens are forms with definite and rather delicate
ornament, by which small evolutionary changes may be
sensitively registered.’ The geologic range of supraspecific
units as well as of species is frequently short. Further-
more, apparently because of the composition and micro-
structure of the shell (which is made up of irregular
foliated layers of calcite with a thin median prismatic layer
of aragonite), pectens often occur abundantly as fossils
where other mollusks (except some other genera such as

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Ostrea) are represented only by casts and moulds. From
a consideration of the features here enumerated in con-
nection with pectens, it is obvious why this group has
furnished some of the most reliable index fossils used in
deciphering the age and correlation of strata.

A striking feature of the Tertiary Pectinidae, as
pointed out by Davies (207), is the great increase in size
during Miocene time. Most specimens from strata of
Eocene or Oligocene age do not exceed 50 mm in
diameter. Very large species described from the late
Tertiary are: Mizuhopecten kamagai Nagasawa, probably
of Pliocene age, in Japan, 280 mm long; Pecten dregeri
von Teppner of Miocene age in Austria, 240 mm long;
Pecten healeyi Arnold in the San Diego Formation,
Pliocene, 222 mm long; and Chlamys (Nodipecten) arnoldi
Aguerrevere, of late Miocene or Pliocene age in Venezuela,
218 mm long. The greatest size reported for a living
species is that of Pecten (Patinopecten) caurinus Gould,
288 mm long and 198 mm high.

The shells of scallops were known to the ancient
inhabitants of Europe. Pecten shells, found in caves in
Europe, were used as receptacles for mixing pigments by
artists of the late Paleolithic age. Pectens were known to
the ancient Greeks and Aristotle studied the sense organs
of some Aegean species. They were also known to early
Amerindians as evidenced by Toltec carvings in the temple
of Quetzalcoatl in Teotihuacan near Mexico City. The
role of pecten shells in art has been mentioned by Bearl
(208). A book (209) published by the Shell Oil Company
contains an extensive account of the history of pecten
shells in the fields of history, literature, art, anthropology
and industry. A scallop (Pecten purpuratus) reported in
that work, an artifact from Chile, was dated at about
3000 B. C.

Some living species of this family especially valuable
as food, have received intensive study. An interesting
feature of the shell is the presence of concentric rings
formed by offsets, or by color changes, during growth,
and best observed on the upper valve. These rings ac-
cording to Risser (210) and Gutsell (211) are a result of a
quiescent period of growth during the spawning season.
It is generally believed that these rings are formed annually,
but this is not always the case because, as pointed out by
Gutsell, rings sometimes are present on young shells which
have not reached maturity. Davenport (212) discussed
the significance of growth lines in fossil pectens as
indicators of past climates.

Bazikalova (213) concluded from a study of Pecten
yessoensis Jay that the rings on the valves are not reliable
indicators of age. He stated that the dark rings on the
whitish-yellow ground of the ligamental pit were formed
annually. These he believed to be reliable indicators of
the age of scallop shells as borne out by application of
this method to Chlamys laeta [C. nipponensis Kuroda]
and C. swifti as well as to P. yessoensis.

About 145 supraspecific units have been proposed
for members of this family. Many of these have little or
no taxonomic value and in some cases their use obscures
interregional relationships, as shown by Fleming (214) in
his studies of Pecten in the western Pacific region.

Many publications, only a few of which will be
mentioned here, deal with scallops because of their im-
portance and their use as guide fossils in correlation of
strata and because of the commercial value of some species

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

for food.

Jackson (215) discussed the phylogeny of the
Pectinidae and pointed out that they originated from a
Pteria-like form. Philippi (216) also discussed their
phylogeny and emphasized “Iteration,” the similarity of
shell characters which appear again and again at different
times and places in species which may not be closely
related. Verrill (217) in 1897 discussed the characters
and classification of the Pectinidae and the same year
Sacco (218) presented a classification of the Tertiary
genera and subgenera of the Mediterranean region. This
was followed in 1898 by Dall (219) who reviewed the
genera and subgenera of Tertiary pectens and included a
review of west American Tertiary species.

A catalogue of Tertiary species and genera was
published by von Teppner (220) in 1922. A number of
genera and subgenera were proposed later for the New

173

Zealand groups by Marwick (221) in 1928, for the Recent
Hawaiian species by Dall, Bartsch and Rehder (222) in
1938, and for the Recent Australian species by Iredale
(223) in 1939. A number of genera proposed by Iredale
have been applied to Japanese species by Habe (224).

A catalogue by Rowland (225) containing supra-
specific nomenclatural units of Tertiary Pectinidae ap-
peared in 1938.

The Cenozoic species of Pectinidae of western
United States were described and illustrated in an ex-
cellent monograph by Ralph Arnold (226). A number
of species from late Tertiary strata in Lower California,
Mexico, were described by Hertlein (227), E. K. Jordan
and Hertlein (228), and by Durham (229). Tertiary
species from the eastern United States have been well
illustrated and described by Tucker-Rowland (230) and
by Mansfield (231).

Key to Genera and Subgenera of Pectinidae

A. Right valve with very slight
or no byssal sinus

a. Right valve highly convex,
beak curved over hinge
line bee Ce
aa. Right valve moderately or
only slightly convex, beak
not decidedly curved over
hinge line.

Oppenheimopecten

b. Right valve moderately
convex, ribs often coarse
and wide; left valve flat or
concave, often with a de-
pressed area beneath beak .

bb. Right valve gently convex,
ribs usually low, numerous;
left valve flat or plano-
convex, no depressed area
beneath apex .

. Pectens. s.

. Flabellipecten

B. Right valve with well-developed
byssal sinus

a. Shell usually not exceeding
10 mm in height; no external
ribs but with very fine threads
or radial rows of spines or
pustulesmans S502). 4. oa.

aa. Shell exceeding 10 mm in
height; external ribs present.

Cyclopecten

b. Valves with about five
coarse major ribs .
bb. Valves with more than
five major ribs.

Swiftopecten

c. Hinge line as long as
valves or nearly so, often
oblique, shell small, thin

ce. Hinge line shorter than
valves; often large, thick.

Leptopecten

d. Both valves rather flattened;
very large, subcircular.

e. Ribs on left valve narrow,
rounded . . Patinopecten
ee. Ribs on left valve narrow
to wide, high with frill-
like flanges .
dd. Both valves moderately
or highly convex.

. Lituyapecten

f. Valves covered with
well-developed, even,
radial striae; hinge
with prominent
cardinal crura or
teeth . es

ff. Valves with spinose or
imbricating sculpture;
hinge with fine (or
no) crura.

. Lyropecten

g. Adult right valve
attached to sub-
strate Se en ee ee

gg. Adult right valve
not attached to
substrate.

. Hinnites

h. Left valve deeper
than right; usually
with spinose or
imbricating sculp-
ture; anterior ear
usually longer than
posterior one . Chlamyss. s.
hh. Right valve deeper
than left; often with
imbricating but no
spinose sculpture;
anterior and posterior
ears nearly equal in
length . Argopecten

174

A classic monograph of Neogene pectens of Europe
begun by Deperet and Roman (232) was completed by
Roger (233). A recent paper by Eames and Cox (234)
deals with Tertiary pectens of Persia and the Mediterranean
region and a paper by Csepreghy-Meznerics (235) dis-
cusses the Neogene Pectinidae of Hungary.

The work of Grant and Gale, 1931, concerning west
American species, and some of the papers of Masuda
containing discussions and illustrations of Tertiary species
of Japan will be mentioned in the present paper in the
discussions of the species. Masuda (236) recorded and
discussed 136 species and subspecies from the Tertiary
of Japan, divided into twenty genera and six subgenera.
A recent paper by MacNeil (237) deals with northern
Cenozoic pectinids.

Recent west American Pectinidae have been dis-
cussed by Hertlein (238) and by Grau (239). Recently
Olsson (240) described a new species from Peru.

Through the courtesy of Dr. F. K. North (241), a
copy of a manuscript by him containing an excellent
discussion of the supraspecific units of the Pectinidae
was available for consultation.

A systematic arrangement of the supraspecific
groups of the Pectinidae by the senior author appeared
recently in “Treatise on Invertebrate Paleontology” (Part
N, Vol. 1, pp. N348-N373, figs. C72-C94, 1969).

GENUS PECTEN MULLER

Pecten Miiller, Zool. Danicae Prod., p. 248, 1776. Nine
species cited including Pecten maximus Linnaeus. —
Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p.
689, 1898. “Type Ostrea maxima Linné.” — Depéret
and Roman, Mém. Soc. Géol. France, Paléo., Mém.
26, (Tom, 10, Fase. 1), pp. 9, 10,1902. “Type Pecten
jacobaeus Linne.”

Janira Schumacher, Essai Nouv. Syst. Hab. Vers Test.
pp. 40, 117, 1817. “pour type de ce genre j’ai donne
la figure de la Janira intermedia P|. Ill. Fig. 4.”

Type species (designated by Schmidt, Versuch
Conch.-Samml., p. 67, 1818). — Ostrea maxima Linnaeus
[Syst. Nat., ed. 10, p. 696, 1758. “Habitat in Oceano
Europaeo.” (References include Lister, Conch., pl. 161,
fig. 1; Gaultieri, Test., pl. 98, figs. A. B.; and others).
Also illustrated by Reeve, Conch. Icon., Vol. 8, Pecten,
sp. 38, pl. 9, fig. 38, 1852. — Dakin, Liverpool Mar. Biol.
Comm., Mem. 17, Pecten, pl. 1, figs. C, D, E, F, 1909.
See also discussion of this species by Dodge, Bull. Amer.
Mus. Nat. Hist., Vol. 100, Art, 1, pp. 163-164, 1952].

Range. — Late Eocene to Recent, worldwide in
warm temperate and tropical marine water. Late Oligocene
or early Miocene to Recent in western North America and
in the Tethyian region; Pliocene to Recent in New Zealand,
Australia, East Indies, Philippine Islands and Japan (242).
Recent in from 9 to 1846 meters (5 to 919 fathoms).

Description. — Shell suborbicular, often large,
inequivalve; right valve convex, the left flat, concave or
slightly convex; auricles moderately large, nearly equal,
delimited from body of shell, a slight byssal sinus, usually
only slightly developed, under the anterior auricle;
ctenolium lacking; sculptured with rather broad, square or
rounded radial ribs which may bear longitudinal threads
or may be nearly smooth, and the whole crossed by fine
concentric imbricating lamellae; in some subgenera (such

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

as Euvola) the radial sculpture consists of grooves; 2 to 4
pairs of cardinal crura radiate from the top of the liga-
mental pit; inner margin of ventral portion of valves
usually scalloped corresponding to the exterior ribbing.

Remarks. — Deshayes (243) discussed the early
usage of the name ‘‘Pecten” and Lovell (244), Stearns
(245), and others have discussed the historic and heraldric
significance of certain species of this group of bivalves,
especially in Europe.

The usage of the generic name Pecten by Osbeck,
1765, accepted by Grant and Gale, 1931, is considered to
be a nomen nudum by most authors. Reasons for that
conclusion are clearly expressed by Stiles (246).

Pectens with convex right and flat or concave left
valves occur early in the Jurassic of North and South
America, and somewhat similar forms occur in the Mediter-
ranean region. Cox (247) recently reviewed the opinions
of some of the earlier authors concerning the classification
of Mesozoic pectens. The early Jurassic forms are
referable to genera such as Weyla J. Bohm (type, Pecten
alatus von Buch) which possess hinge characters different
from modern forms. We are inclined to restrict the use of
the genus name Pecten to Cenozoic species.

Twenty-four species and subspecies of pectens with
concave-convex valves have been described from the late
Cenozoic in the region between California and Peru, three
of which occur in the San Diego Formation. The earliest
representative in this region is Pecten sanctaecruzensis
Arnold (248) from strata of early Miocene age. This
species bears a general resemblance to P. valentinensis
Fontannes (249), from the Burdigalian, early Miocene of
Europe.

Most recent species of Pecten can swim freely by
clapping their valves together. By expelling the water
rapidly from the body cavity, they are capable of exe-
cuting a series of zig-zag movements, the ventral margin
foremost. However, when frightened by an enemy or for
any other reason, they can swim backward with the hinge
foremost. When at rest they lie upon the right valve on
the floor of the ocean. A row of bright eyes occurs along
the edge of the mantle and with these organs the scallop
can detect light and shadow.

The rate of growth varies with different species.
Dakin (250) made an extensive study of Pecten maximus
and found that shells 86 mm in anterior-posterior dia-
meter were 3 1/2 years old. Fleming (251) mentioned
that growth of Recent scallops declines rapidly after
three years but that some may attain an age of 22 years.
The same author gave an excellent discussion (252) of
the western Pacific species of the genus Pecten and their
interregional relationships.

SUBGENUS PECTEN S. S.
Pecten (Pecten) bellus Conrad
Plate 30, Figures 1, 2, 3, 4, 9;

Plate 32, Figure 14; Text figure 7

Janira bella Conrad, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 8, p. 312, December, 1856. Reprint by Dall,
U. S. G. S., Prof. Paper 59, p. 173, 1909. — Conrad,
U. S. Pac. Rail Road Expl., Vol. 6, Pt. 2, No. 2, p. 71,
pl. 3, fig. 16, 1857. ‘‘Locality. — Santa Barbara, Cal. —
Doctor Newberry.”’ — Orcutt, West Amer. Sci., Vol. 6,
whole No. 45, p. 70, July, 1889. ‘‘Pacifie Beach,”

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

“Tertiary.” — Keen and Bentson, Geol. Soc. Amer.,
Spec. Papers No. 56, p. 55, 1944. Earlier records cited.

Pecten Hemphillii Dall, Proc. U. S. Nat. Mus., Vol. 1, p.
15, 1878. ‘San Diego.” “‘Later Tertiaries.”” — Dall,
Proc. U. S. Nat. Mus., Vol. 1, p. 29, 1878. ‘“‘About ten
miles northward from San Diego, on the seacoast of
California.” — Carson, Pan-Amer. Geol., Vol. 43, No. 4,
p. 268, 1925. “‘San Diego fauna.” Pliocene.

Pecten hemphilli Dall, Cooper, Calif. State Min. Bur.,
Seventh Ann. Rept. State Mineral., Vol. 7, p. 257,
1888. “Pl. — San Diego.” — J. P. Smith, Calif. State
Min. Bur., Bull. No. 72, p. 38, 1916. “San Diego and
lower Fernando formations of the coastal region of
southern California.” — J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 9, No. 4, pp. 146, 150, 151, 155,
1919. ‘San Diego,” Pliocene. Also ‘“‘Fernando” and
“Santa Maria faunal zone,’ Pliocene. — Keen and
Bentson, Geol. Soc. Amer., Spec. Papers No. 56,
p. 87, 1944. Dall’s original record cited. Also others.
— Woodring, in Woodring and Bramlette, U. S. G. S.,
Prof. Paper 222, pp. 64, 82, pl. 16, figs. 15, 16; pl.
21, fig. 8, 1950. Cebada and Graciosa members of the
Careaga Sandstone, Santa Maria district; p. 104,
Pacific Beach and inland, San Diego district; p. 106,
“San Diego formation.’”’ — Vedder, U. S. G. S., Prof.
Paper 400-B, p. B327, 1960. ‘San Diego formation at
Pacific Beach.” Also Niguel Formation and localities
in southern California and Lower California.

Pecten (Pecten) hemphillii Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 4, p. 706, 1898. “Found with P.
expansus” [= P. healeyi Arnold]. — Schuchert, Dall et
al. U. S. Nat. Mus., Bull. 53, Pt. 1, p. 488, 1905.
“Pliocene. San Diego, California.”

Pecten (Pecten) hemphilli Dall, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 105, 1903 (as Pecten hemphilli,
p. 63). “Pliocene. — Pacific Beach and Russ School,
San Diego (Hemphill; Dall; Arnold).”” — Arnold, U. S.
G. S., Prof. Paper 47, pp. 28 (as P. hemphilli), 97,
pl. 33, figs. 3, 3a, 3b, 1906. ‘“‘Pacific Beach, Russ
School, and ‘San Diego well’, San Diego,” Pliocene.
Also in Temescal Canyon north of Santa Monica,
California. — Arnold and Anderson, U. S. G. S., Bull.
322, pp. 59, 152 (as Pecten hemphilli), pl. 25, fig. 5,
1907. “One mile north of Schumann station’’, also
from ‘‘Fernando” of Santa Maria district, Pliocene. —
Keen and Bentson, Geol. Soc. Amer., Spec. Papers No.
56, p. 87, 1944. Arnold’s records cited, also others. —
Glibert and Van de Poel, Mém. Inst. Roy. Sci. Nat.
Belgique, Deuxiéme Ser., Fasc. 78, p. 19, 1965.
Pacific Beach, San Diego, Pliocene.

Pecten (Pecten) bellus Conrad, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 103, pl. 21, figs. 1, 2, 1903.
“Pliocene at Santa Barbara, California.” — Arnold,
U.S. G. S., Prof. Paper 47, p. 95, pl. 31, figs. 1, 1a,
1906. Various localities in late Pliocene of southern
California. — Arnold, in Arnold and Eldridge, U.S. G. S.,
Bull. 309, p. 24, pl. 35, fig. 3, 1907. ‘Pliocene, Santa
Barbara. Also found in Pliocene of Ventura, Santa
Barbara, and adjacent Counties.” — Arnold, U.S. G. S.,
Bull. 321, p. 32, pl. 15, figs. 1a, 1b, 1907. ‘‘Bath-
house Beach, Santa Barbara.” “Packards Hill” (p. 32).
— E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci.,
Sci., Ser. 4, Vol. 15, No. 14 pp. 417, 430, pl. 32, fig.
2; pl. 33, figs. 1 and 2; pl. 34, figs. 2, 3, 4, 1926.

175

“Pacific Beach near San Diego, California”, Pliocene.
Also other localities in southern California and Lower
California.

Pecten bellus Conrad, McLaughlin and Waring, Calif.
State Min. Bur., Bull. No. 69, map folio (inside back
cover), sp. No. 46, pl. 1, fig. No. 46, 1914. ‘Fernando
of the Santa Clara River Valley, Ventura Co., California.”
— J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 9,
No. 4, pp. 150, 152, 1919. “San Diego,”
Pliocene. Also ‘“‘Fernando” and “Santa Barbara,”
Pliocene. — Clark, Stratigraphy and Faunal Horizons of
the Coast Ranges of California (Privately Publ.), p. 28,
pl. 40, figs. 1, 2, 1929. Middle and Upper Pico,
Pliocene (cited as ““Pecten (Pecten) bellus Conrad” on
expl. to plate 40). — Hertlein and Grant, Jour. Mines
Geol., Rept. 35 of Calif. State Mineral., p. 69, 1939.
Sandstone overlying basal conglomerate, Pacific Beach,
Pliocene. — Hanna and Hertlein, Calif. State Div.
Mines, Bull. 118, p. 176, fig. 14 (p. 177), 1941. ‘“‘Base
of Santa Barbara sands and marls on trail on northeast
slope of Packard’s Hill, Santa Barbara, California.”
“Upper Pliocene”. — Hertlein and Grant, Mem. San
Diego Soc. Nat. Hist., Vol. 2, Pt. 1, pp. 56, 59,
1944. Upper beds exposed in Pliocene section at
Pacific Beach; also near Mexican Boundary 3/4 mile
from the sea. — Hertlein and Grant, Calif. State Div.
Mines, Bull. 70, Chapt. 2, p. 60, 1954. San Diego
Formation, Pliocene. — Milow and Ennis, 57th Ann.
Mtg. Cordilleran Sec., Geol. Soc. Amer., Field Trip
Guidebook — 1961, San Diego Co.,1961, p. 28. “San
Diego formation.”

Pecten (Janira) bellus (Conrad) variety hemphilli Dall,
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.
1, p. 226 [not all the synonymy], pl. 3, figs. 1a, 1b,
1931. “Middle Pliocene at Pacific Beach, San Diego.”
Also other localities.

Pecten bellus hemphilli Dall, Woodring, Stewart, and
Richards, U. S. G. S. Prof. Paper 195 (table opposite
p. 112), 1941. “Strata at Pacific Beach.’’ Also men-
tioned, p. 111.

Pecten (Pecten) bellus hemphilli Dall, Moore, San Diego
Soc. Nat. Hist., Occas. Paper 15, p. 50, pl. 23, figs.
c,d, 1968. San Diego Pliocene. Also other localities.

Type specimen. — Originally in Academy of Natural
Sciences of Philadelphia. Specimen now missing.

Neotype specimen (designated by Stewart, Acad.
Nat. Sci. Philadelphia, Spec. Paper No. 3, p. 117, 1930.
“The specimen described and figured by Arnold (1906, p.
95, pl. 31) is taken for the neotype of this species.”
“Pliocene, Santa Barbara, Cal.’’). — No. 960, Academy of
Natural Sciences of Philadelphia.

Type locality. — “‘Locality. — Santa Barbara, Cal.
Doctor Newberry.”

Range. — Middle and late Pliocene; southern Cali-
fornia and northern Lower California. Santa Cruz Island,
California; Cedros Island, Lower California.

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 104, 105, 547, 957, 1130, 1138, 1178,
1199, 1400, 1402, 2020, 28453, 28644, 28884, 28886,
28889, 28892, 31356, 1141, 1155, 1176, 1177, 36599.
L.A.M. 107, 122, 124, 127, 180, 302, 205, 305A, 308,

309, A-2081. S.D. 20, 23, 29, 37, 150, 413, 417.
S.D.S.C. 31, 32, 47. U.C.L.A. 296, 307, 1382, 1386,
2420.

176

Original description. — Subtriangular; inferior valve
convex, ribs 14 or 15, square, about as wide as the inter-
vening spaces, very prominent, some of them with one or
two longitudinal obsolete lines; disk finely wrinkled
concentrically; upper valve flattened, deeply depressed
toward the apex; ribs rather narrower than those of the
opposite valve, obscurely bicarinated above, disk orna-
mented with close, fine, squamose, concentric wrinkles.
Length 4 inches; height 3 3/4 inches. (Conrad.)

Description of neotype. — Shell large, thin, in-
equivalve, elegantly, radiately ribbed. Left (upper) valve
slightly convex, the point of greatest convexity being
generally about one-fourth the distance from the apex
toward the ventral margin; between this point of greatest
convexity and the apex there is a deeply depressed area,
the depression generally not affecting the two outer ribs
on each side, which inclose the depression on the sides;
surface of left valve ornamented with 13 or 14 prominent,
flat-topped, sometimes faintly bicarinated, radiating ribs,
which have flat, sloping sides; these ribs become broader,
less elevated, and less sharply angulated near the periphery
in the adult; interspaces slightly wider than the tops of the
ribs, with slightly rounded bottoms; whole surface of left
disk covered with fine, sharp, concentric, regular lamellae;
ears rather small, subequal, slightly concave, finely con-
centrically lamellated, separated from the disk by an im-
pressed line. Right (lower) valve prominently convex, the
point of greatest convexity being about one-third the
distance from the apex to the ventral margin of the disk;
the umbo in this valve curves sharply and meets the plane
of the ears at an angle of about 90 degrees; surface of
right valve ornamented by 14 or 15 prominent, nearly
flat-topped, square, radiating ribs, some of them with one
or two longitudinal obsolete lines; the ribs become some-
what less elevated and the sides more sloping as the
periphery is approached in the adult; surface of right disk
ornamented with close, fine, squamose, concentric
wrinkles; ears subequal, arched, covered with crowded,
elevated lamellae; byssal notch small. Alt. 80 mm.; lat.
108 mm.; diam. 32 mm.; length of hingeline, 45 mm.
(Arnold.)

Remarks. — Fossils here referred to Pecten bellus
occur at nearly every locality where Pliocene fossils are
found in the San Diego area.

We have examined over 600 specimens, the greater
number single valves, varying in size from 8 mm to 78.8
mm high. The number of ribs vary from 12 to 18 but the
average is about 15. The ribs on the ventral portion of
large forms tend to become broad, flat-topped, the sides
slope rather steeply to the interspaces. The ribs on smaller
specimens are higher, narrower and more rounded. The
tops of ribs on large specimens sometimes bear one or more
faint longitudinal grooves. The ribbing on the interior of
valves, which is well defined on the right valve, extends to
the umbonal area, on the left valve to the muscle im-
pression. Low flanges are present on the ribs near the
ventral margin of large valves. There are usually two pairs
of rather weakly developed cardinal crura but these are
not prominent. Auricular crura are well developed on the
left valve but less pronounced on the right valve.

Pecten hemphillii Dall was described from beds of
Pliocene age at San Diego and compared with Pecten
stearnsii rather than with Janira bella Conrad. Several
authors have considered P. hemphillii and P. bellus to

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Text Fig. 7. Pecten (Pecten) bellus Conrad. Hypotype
(Cat. No. 2408, University of California at Los Angeles),
from Pacific Beach, San Diego; Pliocene. Length 63 mm.
A. Right valve. B. Left valve. (Drawn by E. H. Quayle.)

represent the same species. E. K. Jordan and L. G.
Hertlein accepted this viewpoint. Grant and Gale cited
P. hemphillii as a variety of P. bellus and stated (p. 886,
pl. 3, fig. 1a), “This variety is practically indistinguishable
from the typical variety.” Woodring, in a recent paper
(1950), considered the two forms to be closely related but
separable, with P. hemphillii being smaller and not
exceeding 60 mm in height. We have had available for
study five specimens collected by Henry Hemphill and
labelled by him ‘“‘Pecten hemphillii Dall. Original lot.
Pacific Beach, Cal. San Diego.” The largest of these,
No. 526a (Calif. Acad. Sci. Dept. Geol. Type Coll.),
is 88 mm long, 78.8 mm high, convexity (both valves to-
gether), 24 mm. The ribs at the ventral margin are 7.5
mm wide (see plate 30, figures 4 and 9). This specimen, in
all shell characters, is similar to specimens of P. bellus
collected by Tom Dibble at Packard’s Hill, Santa Barbara,
California, and by others in that area.

The other four specimens from the original lot of
P. hemphillii vary as to the width of the ribs. Two show a
decided widening toward the ventral margin, the ribs of
the other two remain quite narrow and with vertical sides
for their entire length. A large right valve collected by
G. P. Kanakoff at Loc. 107 (LAM) at the end of Arroyo

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Drive, San Diego, is 86 mm long and 77.5 mm high. This
specimen in ribbing and other shell characters resembles
P. bellus. It is true that very large specimens from strata
of late Pliocene age at Santa Barbara and other localities
attain a greater size. Conrad’s type specimen was described
as 4 inches (approximately 101 mm) long, and Gabb’s
specimen illustrated by Arnold and designated as a neotype
by Stewart is 108 mm long and 80 mm high. The largest
specimen from the San Diego Formation observed by us
is 88 mm long and 78.8 mm high. Arnold stated that
specimens to a height of 20 mm are hardly separable into
two species. A study of the specimens before us seems
to indicate that the chief difference between P. bellus and
P. hemphillii is that the former may attain a greater size.
However, large specimens from the San Diego Formation
apparently do not differ in any constant shell characters
from P. bellus. We therefore agree with the conclusion of
E. K. Jordan and Hertlein who considered P. bellus and P.
hemphillii specifically identical, and stated concerning the
latter, ““The type of P. hemphillii, as indicated by the
illustration furnished by Arnold, is an intermediate form
not exactly similar to either extreme of the series, al-
though it inclines toward the narrow-ribbed variants.”

This opinion is supported by the observations of
Druckerman (253) who examined more than 80 specimens
of the P. bellus-hemphillii series. These varied from 19 to
130 mm in length, average 57 mm; 17 to 99 mm in height,
average 51 mm; umbonal angle 89° to 107°, average 97°;
right valve with 12 to 17 ribs, average 15; left valve with
11 to 16 ribs, average 14. He concluded that ‘as the
relations of the two forms remain moot, they are
arbitrarily placed in synonymy.”

Two specimens from Pliocene strata on the east
coast of Lower California were illustrated by Durham
(254) under the name of P. bellus var. hemphilli. The
right valve, 77.5 mm long (incomplete), differs from P.
bellus in the proportionately larger and only slightly con-
vex ears and in the general character of the radial ribs.
The left valve, 126.5 mm long, with traces of a midrib in
the interspaces and finely radially sculptured ears is not
typical of P. bellus but somewhat resembles the cor-
responding valve of one of the P. bakeri group, perhaps
P. bakeri diazi (255). Vokes (256) mentioned the oc-
currence of a fossil form which he considered to be an
undescribed subspecies of P. bellus bearing 22 ribs from
the Infierno Formation of late Pliocene age in the Santa
Rosalia area, Lower California.

The species described as Pecten (Pecten) auburyi
Arnold (257) appears to be only a variant of P. bellus.
We have examined a paratype, a right valve, slightly dis-
torted (No. 78, Calif. Acad. Sci. Dept. Geol. Type Coll.),
from the type locality in Puente Hills in Los Angeles Co.
It is 47.6 mm long and 41.8 mm high. It has rather nar-
row ribs similar to those on the earlier stages of P. bellus
and is inseparable from some forms labelled P. hemphillii.

Pecten (Pecten) lecontei Arnold (258) described
from Cedros Island, Lower California, is quite distinct
from P. bellus and its variants. The ribs, about 18 on the
right valve and 17 on the left, are round-topped. Those on
the right valve usually quite smooth, separated by flat-
bottomed interspaces which are narrower than the ribs.
The left valve is usually slightly concave and the rounded
ribs are quite different from the high usually flat-topped
ribs of P. bellus.

177

Pecten (Pecten) slevini Dall and Ochsner (259)
described from strata of Pliocene age on the Galapagos
Islands differs from P. bellus and its variants by the nar-
rower, rounded ribs on the right valve which are separated
by wider interspaces, and by the wider apical angle.
The specimen which Grant and Gale (260) illustrated as P.
bellus var. slevini from beds of Pliocene age in Los Angeles
Co. appears to be quite different from the type of P.
slevini, the chief feature of similarity being the wide
apical angle. It is probably a distorted specimen of P.
bellus. [Illustrations of P. archon Maury (261) bear a
resemblance to P. slevini but that Miocene Caribbean
species has fewer ribs, which on the right valve are shal-
lowly bifid toward the ventral margin.

The shell of Pecten bellus bears a general resemb-
lance to that of P. albicans Schroter (262) and to P.
excavatus Anton (263), which have fewer ribs, but close
relationship with these Japanese species has not been
demonstrated.

Some authors have suggested that Pecten bellus
could be placed in the supraspecific group named Notovola
by Finlay. Fleming (264), however, stated that Notovola
“has no phylogenetic unity,” that relationship exists be-
tween relatives of the type species, P. novaezelandiae
Reeve, and the Mediterranean species P. jacobaeus which is
referable to Pecten s. s. and that Finlay’s genus is an un-
warranted supraspecific unit.

SUBGENUS FLABELLIPECTEN SACCO

Flabellipecten Sacco, Bol. Mus. Zool. e Anat. Comp.
(Torino), Vol. 12, No. 298, p. 102, June 11, 1897. —
Saeco, Moll. Terr. Terz. Piemonte e Liguria, Pt. 24,
p. 55, December, 1897. “tipo F. flabelliformis (Br.).”
— Deperet and Roman, Mém. Soc. Géol. France,
Paléo., Tom. 18, Fase. 2 (Mém. No. 26 (suite), p. 105,
1910. — Cossman and Peyrot, Act. Soc. Linn. de
Bordeaux, Vol. 68 (Conch. Néogéne |’ Aquitaine, Tom.
2, Livr. 2), p. 272, 1914. “(G. -T. Pecten flabelliformis
Brocchi, Plioc.).”” — Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 159, 1961. ‘“‘type species by original designation
and tautonomy, F. flabelliformis Brocchi.”

Type species (by original designation). — ‘‘Flabel-
lipecten flabelliformis (Br.) (tipo del nuovo sottog.).”
[= Ostrea flabelliformis Brocchi, Conch. Foss. Subapennina,
Vol. 2, p. 580, 1814. “Fosile nel Piacentino e in Valle di
Andona.” Pliocene. Illustrated by Depéret and Roman.
Mém. Soc. Géol. France, Paléo., Tome 1, Fase. 1, (Mém.
No. 26 (suite)), p. 139, pl. 19 (Mem. 26, pl. 18), figs. 1,
la, 2, 1912. ‘‘Topotype de l’Astien du Val d’Andona
pres Asti (Italie).”” — Ronchetti, Riv. Ital. Paleo. e Strat.,
Mém. 5, Pt. 1, p. 30, fig. 10a, b, c, 1952. [Illustration of
type specimen. |

Range. — Early Miocene (Aquitanian) to late
Pliocene in the Mediterranean region; (265) Miocene (late
and perhaps middle) and Pliocene in the Caribbean region;
Middle Miocene to Recent in North and Central America.

Description. — Shell large or of medium size and
thickness, apical angle wide. Right valve only moderately
convex, the umbo slightly incurved; sculpture commonly
consisting of numerous, low, often rounded (but oc-
casionally squarish) radial ribs which are smooth on top or
occasionally shallowly longitudinally grooved, the ribs

178

separated by narrower interspaces; ears subequal, a slight
byssal notch at the base of the right ear. Left valve flat
or plano-convex; the ribs narrower and the interspaces
wider than those on the right valve and often bearing an
interstitial thread. Exterior of both valves crossed by fine
imbricating lines of growth. Hinge with two to four
cardinal crura. The radial flutings on the interior extend
inward from the ventral margin about one third the length
of the valves. (Adapted from Depéret and Roman, and
from Olsson.)

Remarks. — Flabellipecten differs from Pecten s. s.
in the less highly arched right valve which is only slightly
incurved at the apex, greater apical angle, smaller ears,
more numerous and usually lower radial ribs and in that
the left valve is flat or slightly convex and lacks a de-
pression in the umbonal region.

Some American species from time to time have
been referred to Flabellipecten. Toula (266) in 1908
placed P. gatunensis, described from beds of Miocene age
in Panama, in Flabellipecten, and Depéret and Roman in
1912 mentioned that “Fil. floridus” [= P. diegensis Dall]
was a member of the Flabellipecten group. Hertlein
(1935, p. 303) mentioned the similarity of P. diegensis to
the European Miocene species, P. fraterculus Sowerby,
and to the P. besseri group, and also called attention to
several similar east American species. Recently Olsson
(1961, p. 159) placed in this category, P. gatunensis and
P. macdonaldi Olsson, both species of Miocene age in
Central America, and P. sericeus and P. diegensis, Recent
west American species. Roger (1939, p. 264) mentioned
the great number of species of Flabellipecten in the
Atlantic region and intimated the possible origin of this
group in the Americas.

Species such as P. gatunensis, P. macdonaldi, P.
bosei, P. sericeus, and P. diegensis bear a close resemblance
to species assigned to Flabellipecten by European authors.
Pecten hawleyi Hertlein (267), from the early Miocene
(Vaqueros Formation) of California, may be a member of
this subgenus. Other species such as P. stearnsii Dall,
P. carrizoensis Arnold and P. beali Hertlein, described
from strata of Pliocene age in southern California and
Lower California, differ from the type species of Flabel-
lipecten in the fairly high, medially sulcated ribs but they
are believed to be allied to P. diegensis and should be in-
cluded in the same supraspecific taxonomic category.
Several east American species of late Cenozoic age are
members of this same group, including P. soror Gabb,
from the Miocene of Santo Domingo, P. soror codercola
Harris, from the late Tertiary of Venezuela, P. ochlock-
oneensis Mansfield and P. ochlockoneensis violae Tucker,
from strata of Miocene age in Florida and P. hemicyclus
Ravenel from beds of Pliocene age in South Carolina.

Some of the American species here referred to
Flabellipecten differ considerably from the type species
of Flabellipecten in the character of the ribbing and
especially in the fewer cardinal crura. These shell
characters, however, vary in the numerous fossil forms
described from the Mediterranean region which have been
assigned to Flabellipecten.

This American group could be placed in a new
subgeneric category but we hesitate to add another
supraspecific unit for these species whose shell characters
so closely resemble species of the Flabellipecten group.
Furthermore, the taxonomic value of such a new subgeneric

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

unit would be questionable, especially if the statement of
Deperet and Roman (1910, p. 107) (268) is taken into
consideration, that shell characters of some species reveal
gradation of Flabellipecten into Pecten s. s.

Pecten (Flabellipecten) stearnsii Dall
Plate 29, Figures 2, 4; Plate 35, Figure 10; Text Figure 8

Janira florida Hinds, Dall, Proc. Calif. Acad. Sci., Vol. 5,
p. 297, December, 1874. (Printed separately March
26, 1874). “well at San Diego,” “Pliocene.” — Dall,
Proc. U. S. Nat. Mus., Vol. 1, p. 28, 1878. Well at
San Diego. — Cooper, Calif. State Min. Bur., Seventh
Ann. Rept. State Mineral., Vol. 7, p. 244, 1888.
“P]. — San Diego well.”

Not Pecten floridus Hinds, 1844 = Pecten diegensis Dall,
1898.

Not Ostrea florida Gmelin, 1791, a Pecten.

Pecten stearnsii Dall, Proc. U. S. Nat. Mus., Vol. 1, pp. 11,
14, March 27, 1878. ‘“‘Later Tertiary of San Diego.” —
Dall, Proc. U.S. Nat. Mus., Vol. 1, p. 29, 1878. “About
10 miles northward from San Diego, on the seacoast of
California,’ ‘(stratum C)”. — Cooper, Calif. State
Min. Bur., Seventh Ann. Rept. State Mineral., p. 258,
1888. “Pl. — San Diego.” — J. P. Smith, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 9, No. 4, pp. 150, 151, 1919.
“San Diego,” Pliocene. — Woodring, in Woodring and
Bramlette, U. S. G. S., Prof. Paper 222, p. 104, 1950.
Pacific Beach and inland, San Diego, Pliocene. —
Hertlein and Grant, Calif. State Div. Mines, Calif.
Jour. Mines Geol., Rept. 35 of State Mineral., pp. 69,
70, 1939. “In the massive yellowish and gray sand-
stone overlying the basal conglomerate” “‘at Pacific
Beach;” south slope of Mount Soledad, and “Along
India Street,” San Diego. — Hertlein and Grant, Mem.
San Diego Soc. Nat. Hist., Vol. 2, Pt. 1, p. 56, 1944.
“Pacific Beach,” p. 57, “south sloping spurs of Mount
Soledad,” p. 59, “excavations along India Street,
particularly at the corner of Upas Street.”” — Keen and
Bentson, Geol. Soc. Amer. Spec. Papers No. 56, p. 94,
1944. Earlier records cited. — Hertlein and Grant,
Calif. State Div. Mines, Bull. 170, chapter 2, p. 60,
1954. ‘San Diego formation.” Pliocene.

Janira dentata Sowerby, Cooper, Calif. State Min. Bur.,
Seventh Ann. Rept. State Mineral., Vol. 7, p. 244,
1888 (in part). “Pl. — San Diego well.”

Not Pecten dentatus J. Sowerby, 1829, nor Pecten
dentatus G. B. Sowerby, 1835.

Pecten (Pecten) stearnsii Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 4, p. 706, pl. 26, fig. 5, 1898. “With
P. expansus” [i.e. “Pliocene of Pacific Beach (lower
horizon), near San Diego, California.” — Arnold, Mem.
Calif. Acad. Sci., Vol. 3, pp. 63 (as Pecten stearnsii),
106, pl. 12, fig. 3, 1903. “San Diego (Pacific Beach,
lower horizon).’’ — Schuchert, Dall, et al., U. S. Nat.
Mus., Bull. 53, Pt. 1, p. 490, 1905. ‘Pliocene. San
Diego, California.” — Arnold, U. S. G. S., Prof. Paper
47, pp. 28 (as Pecten stearnsii), 100, pl. 32, figs, 1, 1a,
1906. ‘Pacific Beach, near San Diego.” — Arnold in
Eldridge, U. S. G. S., Bull. 309, pp. 242, 244, pi. 35,
fig. 2; pl. 36, fig. 4, 1907. “San Diego formation
(Pliocene), Pacific Beach, San Diego County.” —
Arnold and Anderson, U. S. G. S., Bull. 322, pp. 59,
152, pl. 25, figs. la, 1b, 1907. “San Diego formation

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

(Pliocene), Pacific Beach, San Diego County, Cal.” —
Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, p. 48, 1944. San Diego well [Dall’s
record of “Janira florida, Hds.”]|; p. 56 (as Pecten
stearnsii, ‘‘Pacific Beach.”, p. 57 (as Pecten stearnsii),
“south sloping spurs of Mount Soledad,’ p. 59
(as Pecten stearnsii), ‘““excavations along India Street,
particularly at the corner of Upas Street,” San Diego.
— Milow and Ennis, 57th Ann. Mtg. Cordilleran Sec.,
Geol. Soc. Amer., Field Trip Guidebook San Diego Co.
1961, p. 28, 1961. “San Diego formation.” Pliocene.
— Glibert and Van de Poel, Mem. Inst. Roy. Sci. Nat.
Belgique, Deuxieme Sér., Fasc. 78, p. 21, 1965. Pacific
Beach, San Diego, Pliocene (as Pecten (s. s.) stearnsi).
— Moore, San Diego Soc. Nat. Hist., Occas. Paper 15,
p. 48, pl. 22, figs. a, b, 1968 (as Pecten (Pecten)
stearnsi). Pacific Beach, Pliocene.

Pecten cf. P. diegensis Dall, Dall cited by Ellis, in Ellis
and Lee, U. S. G. S., Water Supply Paper 446, p. 63,
1919. Fossil Canyon, about 3 1/4 miles east of Chula
Vista and 1 1/4 miles southeast of Bonita. “Upper
Miocene.” |[ Pliocene. |

Pecten (Janira) stearnsii variety stearnsii Dall, Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 223,
pl. 3, figs. 1a, 1b (Holser Canyon), 1931. ‘Pliocene:
Pacific Beach, San Diego.” Earlier records cited.

Type specimen. — No. 7942, United States National
Museum.

Type locality. — ‘“‘well at San Diego,” California.
“Pliocene.”

Range. — Middle to late Pliocene (possibly to early
Pleistocene).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 104, 105, 547, 1132, 1138, 1181, 1182,
1183, 1186, 1199, 1399, 1401, 1404, 1413, 1414, 1415,
2015, 28644, 28885, 28889, 28893, 33334, 35025.
L.A.M. 107, 121, 122, 180, 305, 309, 1178, A-1323.
S.D. 2, 4, 5, 75, 80, 88, 331, 404, 417. U.C.L.A. 294,
295, 299, 300, 312, 2359, 2407, 2420.

Original description. — Shell moderately large, thin,
regular; elegantly radiately ribbed. Upper valve flattened
or even a little concave, with about twenty-four regularly
rounded, vaulted, even ribs, separated by slightly wider
channelled interspaces; the whole surface covered with
fine, sharp, concentric, regular lamellae, a little looped
backward over the top of the ribs, but showing no ap-
pearance of reticulation anywhere; ears small, nearly
symmetrical, covered with more elevated, crowded, con-
centric lamellae, especially near the margins; hinge-
margin straight, or even a little concave toward the umbo;
peripheral margins of the valves strongly and regularly
crenulated and interlocking; interior regularly deeply
grooved, to correspond with the external ribs; lower valve
slightly convex, with about twenty-six regular even ribs,
separated by channelled interspaces somewhat narrower
than the ribs; the top surface of each rib is flattened with
a broad, shallow groove in the middle. with one or two
faint riblets on each side of the groove; the whole surface
is covered with concentric lamellae, like those of the
upper valve, but less sharp, and about twice as crowded.
Ears subequal, arched, covered with crowded, elevated
lamellae; byssal notch very small. Height of shell, 90 mm;
breadth, 100 mm; breadth of hinge-line, 34 mm; thickness,
15 mm. (Dall.)

179

i
=
=

duet

Text Fig. 8. Pecten (Flabellipecten) stearnsii Dall. Hypo-
type (Cat. No. 2407, University of California at Los
Angeles), from Pacific Beach, San Diego; Pliocene. Length
105.6 mm. A. Right valve. B. Left valve. (Drawn by
E. H. Quayle.)

Remarks. — This species occurs rather abundantly
at various localities including the beds in the upper portion
of the Pliocene section at Pacific Beach, also on the south
slope of Mount Soledad and on the San Diego Mesa.

Three specimens of the type lot collected by Henry
Hemphill bear the numbers 525, 525a, 525b in the series
of type specimens in the California Academy of Sciences.
The largest of these is 97.6 mm long, 83 mm high, con-
vexity (both valves together), 18.3 mm. A large left
valve from Loc. 1401 (CAS), south slope of Mount
Soledad is 100 mm long and 85 mm high.

Pecten stearnsii is an extinct species and, as
mentioned by Dall and by Arnold, it is the precursor of
P. diegensis Dall (269), a Recent species which occurs at

180

the present time in waters off San Diego.

Pecten stearnsii differs from the Recent species in
the greater number of ribs, 23 to 26 on the right valve
and about 24 on the left valve in comparison to 19-21 on
the right valve of P. diegensis and 20-21 on the left one.
Furthermore, the hinge line of P. stearnsii is shorter, the
ribs are usually more deeply medially suleated and the
interspaces between the ribs are narrower than those of
P. diegensis. Woodring, Bramlette, and Kew (1946, p. 80)
called attention to the fact that near the margin of the
interior of the right valve of Pecten diegensis a flange
occurs along each edge of the projection corresponding
to the interspace on the exterior. Similar flanges appear
to be lacking or but slightly developed near the anterior
and posterior ends of the right valve of P. stearnsil.

The two forms are very similar but in our opinion
the differences are sufficient to justify recognition of each
as a separate species. Grant and Gale (1931, p. 223) and
Woodring, Bramlette, and Kew (1946, p. 80) considered
Pecten diegensis to be a subspecies of P. stearnsii.
Pecten lunaris Berry (270), a Recent species described
from the Gulf of California, is a member of this group.

Pecten sericeus Hinds (271), a Recent species
originally described from Panama, differs from P. stearnsii
and P. diegensis in that the ribs, especially toward the
ventral margin on adult right valves, often develop a low,
median, tricarinate ridge.

Three fossil forms of Pliocene age in the Gulf of
California region are closely allied to P. stearnsii.

Pecten carrizoensis Arnold (272) described from
strata of Pliocene age in eastern San Diego County, has
fewer (18 or 19 on right, 17 on the left valve) and less
prominent ribs, which are separated by narrower inter-
spaces than those on P. stearnsii.

Pecten beali Hertlein (273) described from strata of
Pliocene age on the east coast of Lower California, differs
from P. stearnsii in that the ears of the right valve bear
radial riblets and in that a fine radial riblet occurs in each
interspace between the radial ribs on the left valve.
Pecten ochlockoneensis violae Tucker (274) from beds of
Miocene age in Florida is an allied species.

Pecten bosei Hanna and Hertlein (275), described
from beds of Pliocene age on the east coast of Lower
California, differs from P. stearnsii in possessing lower,
nonsulcated, often almost smooth ribs. Specimens from
Pliocene beds in the Gulf of California region referred to
P. stearnsii by Hanna and Hertlein (1927) are not typical
of that species, but are more nearly allied to P. bosei.
Vokes (276) cited a species under the name of ‘‘Patino-
pecten cf. stearnsii’’ from the Gloria Formation of
Pliocene age on the east coast of Lower California.

Pecten soror Gabb (277), described from beds of
Miocene age in Santo Domingo and Pecten soror
codercola Harris (278), described from late Tertiary
strata in Venezuela, apparently are members of the P.
stearnsii group.

Pecten stearnsii occurs rather commonly in beds of
middle and late Pliocene age along the coastal region
of southern California from Ventura County to San
Diego and along the west coast of northern Lower Califor-
nia, at Cedros Island, Turtle Bay, and elsewhere on the
peninsula and at Maria Madre Island, Tres Maris Islands.
We have not seen typical specimens of P. stearnsii from
strata other than of Pliocene age. However, the specimens

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

illustrated by Woodring, Bramlette, and Kew (1946, pl. 32,
figs. 14, 15), from unit 1 of the Timms Point silt at San
Pedro, appear to be referable to this species. Those
authors considered this silt to be of Pleistocene age but
many authors earlier considered it to be of late Pliocene
age.

Pecten stearnsii is allied to P. diegensis. The former
species may have occupied habitats similar to P. diegensis,
which lives in west American waters from Cordell Bank,
off central California, to Gorda Bank, off Cape San Lucas,
Lower California, Mexico. The bathymetric range of P.
diegensis given by Grau is 9 to 366 meters (5 to 200
fathoms). According to Fitch (279) “This scallop
usually swims a few feet off the bottom in rocky areas
from five to seventy-five fathoms beneath the surface.”
It occurs in beds of Pleistocene age in southern California.

SUBGENUS OPPENHEIMOPECTEN VON TEPPNER

Oppenheimopecten von Teppner, Fossilium Catalogus 1:
Animalia Pars 15, Anisomyaria II, p. 254, 1922. — von
Teppner, quoted in Roger, Mém. Soc. Geol. France,
Nouv. Ser., Tome 17, Fasc. 2-4, Feuilles 7-43, Mem.
No. 40 (suite et fin du Mém. de Paléo., No. 26 et du
Mém. N. S., No. 10), p. 242, 1939. Type P. sub-
benedictus Fontannes. — Grau, Allan Hancock Pac.
Exped., Vol. 23, p. 148, 1959. Type Pecten sub-
benedictus Fontannes.

Convexopecten Tucker-Rowland, Jour. Conch., Vol. 21,
No. 3, p. 82, September 22, 1938. “with genotype
Pecten (Convexopecten) josslingi (Smith), Quart. Jour.
London Geol. Soc., 3:419, pl. XVI, figs. 10-12, 1847.”

Type species (by original designation, von Teppner,
1922, p. 254). — “Typus: Pecten (Oppenheimopecten)
subbenedictus Fontannes.” [Pecten subbenedictus Fon-
tannes, Etudes stratigraphiques et paléontologiques pour
servir a Vhistoire de la période tertiare dans le Bassin du
oe III, le Bassin de Visan (Vaucluse), (Lyon), p. 83,

2, fig. i 1878. — Deperet and Roman, Mem. Soc.

Baa France, Paléo., Tome 10, Fasc. 1, Mem. No. 26,

p. 39, pl. 5, figs. i Lakes 1902. Southern France,

Burdigalian, Miocene. |

Range. — Early Miocene (Burdigalian) to Recent.
Recent in Indo-Pacific, Australia, Japan, Hawaii, and in
the eastern Pacific, in shallow tropical and subtropical
waters.

Original description (translation). — Inequivalve,
right valve strongly convex (umbo strongly incurved) with
rounded ribs, broader than the interspaces. Ears large,
unequal. Ribs of left valve flat and broad, narrower than
the interspaces. Concentric sculpture of right valve very
weak, the left distinct. (Translation by Grau of von
Teppner’s original description in Roger.)

Remarks. — The most characteristic feature of this
subgenus is the very highly convex right valve with in-
curved umbo overhanging the left valve. The left valve
may be nearly flat or shallowly to moderately concave.

In the Mediterranean region, Oppenheimopecten is
represented by perhaps fifteen or more species aid sub-
species described from strata of Miocene and Pliocene
age. In the eastern Pacific this subgenus is represented by
eight species, P. juanensis Grant and Eaton in the late
Miocene, P. coalingaénsis Arnold in Anderson, P. hartmanni
Hertlein, and P. heimi Hertlein in the Pliocene, and the

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Recent species, P. galapagensis Grau, P. hancocki Grau,
P. perulus Olsson and P. vogdesi Arnold. In the Indo-
Pacific region, Oppenheimopecten is represented from
Pliocene to Recent, including Recent species such as P.
erythraeensis Sowerby, P. fumatus Reeve, P. albus Tate
and P. excavatus Anton.

Fleming (280) gave an excellent discussion of the
members of the Pecten benedictus group (referable to
Oppenheimopecten), in New Zealand and Australia.

Pecten (Oppenheimopecten) vogdesi Arnold
Plate 29, Figures 1, 3, 5, 6

Pecten dentatus Sowerby, Proc. Zool. Soc. London for
1835, p. 109, October 9, 1835. “Hab ad Sanctam
Elenam.” “Found among sand and stones in twelve
fathoms.”” — Sowerby, Thes. Conch., Vol. 1, p. 49, pl.
15, figs. 105, 106, 1842.

Not Pecten dentatus J. Sowerby, 1829. Fossil in Great
Britain.

Pecten excavatus Valenciennes, Zool. Voy. Venus, pl. 19,
figs. 1, la, 1b, 1c, 1846. [No description or locality. |

Not Pecten excavatus Anton, 1839. China.

Janira dentata Sowerby, Dall, Proc. U. S. Nat. Mus.,
Vol. 1, pp. 11, 28, 1878. “Well” at San Diego. —
Cooper, Calif. State Min. Bur., Seventh Ann. Rept.
State Mineral., p. 244, 1888. [Quaternary records
only according to Arnold, 1906.] — Orcutt, West Amer.
Sci., Vol. 6, Whole No. 46, p. 86, August, 1889. Dall’s
record (1878) cited. — Orcutt, quoted by Ellis in
Ellis and Lee, U. S. G. S., Water Supply Paper 446,
p. 60, 1919. Dall’s record (1878) cited.

Pecten (Pecten) dentatus Sowerby, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 104, pl. 12, figs. 1, 1a, 1903.
Pleistocene and Recent. P. 105, “Pliocene. — San
Diego well (Cooper) — (Probably P. hemphilli).””

Pecten (Pecten) vodgesi Arnold, U. S. G. S., Prof. Paper
47, p. 100, pl. 33, figs. 1, 1a, pl. 34, fig. 1, 1906.
“The type of this species (a right valve) is from the
upper San Pedro formation at San Pedro,” California,
Pleistocene. Also cited from “Pliocene (?). San Diego
(Hemphill); Cholas Valley near San Diego (Stearns).”
— Arnold in Eldridge, U. S. G. S., Bull. 309, p. 242,
pl. 35, fig. 5 (Pleistocene, Ventura County), 1907.
“Also occurs in supposed Pliocene near San Diego.”
— Olsson, Mollusks of the Tropical Eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), p. 158, pl. 20,
figs. 4, 4a, 4b, 1961. Range: Magdalena Bay, Lower
California, Gulf of California to Panama.

Pecten (Euvola) cataractes Dall, Nautilus, Vol. 27, no. 11,
p. 121, March, 1914. “For this common species of
the Gulf of California I propose the name of Pecten
(Euvola) cataractes.”’

Pecten (Janira) vogdesi Arnold, Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 228, pl. 3, figs. 3a and
3b (Recent, Gulf of California), 1931. ‘Pliocene:
31st Street and Logan Avenue, San Diego (Sternberg
Collection, 1924, specimen at Stanford University).”
Karlier records cited.

Pecten (Oppenheimopecten) vogdesi Arnold, Grau, Allan
Hancock Pac. Exped., Vol. 23, p. 149, pl. 55, 1959.
Pliocene to Recent. Recent, Punta Eugenia, Lower
California, to the Gulf of California and South to
Paita, Peru.

181

Type specimen. — No. 4 Stanford University, De-
partment of Geology. Type Collection.

Type locality. — “from the upper San Pedro forma-
tion at San Pedro”, Los Angeles County, California;
Pleistocene.

Range. — Middle Pliocene to Recent. Recent from
Punta Eugenia, western Lower California, Mexico, to the
head of the Gulf of California and south to Panama, in 4
to 219 meters (2 to 120 fathoms) (Grau). “Usually found
in sand, sandy mud, or mud bottom, associated with coral,
coralline or sponge.”’ (Grau.)

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 1137. L.A.M. 320, 320A, P.87: No. 8325.
S.U. Same locality as C.A.S. 1137.

Original description. — Shell similar to P. excavatus,
except averaging larger and with the following differences:
Right valve, somewhat less convex, has 19 or 20 broader,
flatter ribs, which are separated by relatively broader
interspaces that occasionally show faint intercalary rib-
lets or faint longitudinal striations. Left valve with fewer
ribs than P. excavatus, and having no intercalary riblets, or
faint ones, which become obsolete near the periphery of
the disk; ears slightly less concave than in P. excavatus.
(Arnold.)

Dimensions. — Alt. 69 mm; hinge line to ventral
margin (right valve) 67 mm; long. 73 mm; hinge line
35 mm; diameter 24 mm; umbonal angle (left valve) 98°.
(Arnold.)

Remarks. — This species was recorded from the San
Diego well by Dall and by Cooper. Arnold (1906) did not
refer to Dall’s record (1878) of this species from the San
Diego well, but he did mention that Cooper’s record (pre-
sumably based upon that of Dall) of “Janira dentata” was
in part referable to P. stearnsii. Whether or not Dall’s
record should be referred to P. stearnsii is unknown to us.
Arnold mentioned that specimens of this species were
collected by Stearns from beds of Pliocene age in Las
Chollas Valley and that others were collected by Hemphill
in San Diego in strata of probable Pliocene age.

One right valve and three left valves in the collections
of the California Academy of Sciences, were collected by
Charles Sternberg from 31st Street near 32nd Street and
Logan Avenue, San Diego. One right and one left valve
from the same locality are in the collections of Stanford
University. One right and two left valves from 32nd and
Woolman streets, San Diego, are in the collections of the
Los Angeles County Museum. One of the left valves is
110 mm long and 90.5 mm high. Additional specimens
were collected by Kanakoff at Locs. 320 and 320A, and
at 835, 32nd Street, San Diego.

These specimens occur in fine, hard, gray, cemented
sandstone. Some of them are of a reddish-brown color.
The largest, a left valve from Loc. 320A, is 111.5 mm long
and 86.9 mm high. According to Kanakoff, these speci-
mens, along with specimens of Pecten circularis and other
species embedded in hard matrix, occur in beds definitely
referable to the San Diego Formation. Above this bed is
a layer about a foot thick containing abundant Chione
californiensis and Lucina nuttalli. The preservation of the
Chione and the lithology of the reddish-brown bed are
clearly not referable to the San Diego Formation.

The observable shell characters of the Pliocene P.
vogdesi do not differ from Recent specimens. On some
left valves the interspaces lack a radial riblet but on others it

182
is present. This feature varies in both fossil and Recent
specimens. The hinge of juvenile specimens has but one

pair of crura but adults have two pairs.

Pecten (Pecten) heimi Hertlein (281) described from
strata of Pliocene age in Lower California is a similar
species but that it is identical with P. vogdesi, as believed
by Grant and Gale, is open to question. The ears of the
type specimen are weakly sculptured and the ears of the
left valve are smooth, whereas the ears of Recent P.
vogdesi are ornamented with well defined riblets.

Pecten (Pecten) juanensis Grant and Stephenson
(282), described from beds of late Miocene age in San
Luis Obispo County, California, has smooth ears and the
apical angle is about 90° rather than 95° to 100° in P.
vogdesi. Grant and Stephenson suggested that P. juanensis
might be the precursor of P. coalingaénsis Arnold in
Anderson (283), and P. vogdesi.

Pecten (Oppenheimopecten) hancocki Grau (284),
a Recent species from Cocos Island, has only 16 to 17
ribs and the right valve is much less convex than that of
P. vogdesi and it differs in other details.

In general appearance P. vogdesi bears a general
resemblance to some members of the P. benedictus group
and especially the P. aduncus group (285) in the Miocene
of the Mediterranean region but there are differences in the
shape of the ribs and in other details.

Except for its occurrence in the San Diego Forma-
tion, Pecten vogdesi has been reported from southern
California only in beds of Pleistocene age. It is known to
occur in beds of Pliocene and of Pleistocene age in the
Gulf of California region as well as in Pliocene strata at
Maria Cleofa Island, Tres Maris Islands, and in beds of
Pleistocene age at Magdalena Bay, Lower California. It
also has been reported from beds of Pleistocene age along
the coast of Panama and Ecuador. This interesting species
has been taken at many localities in the Gulf of California.

The range of Recent P. (O.) vogdesi usually cited in
the literature, is from the Gulf of California to Paita, Peru.
Olsson recently mentioned that this species does not occur
south of Panama and that he observed no specimens from
south of Mexico. He described a species from Santa
Elena, Ecuador, under the name of Pecten (Pecten)
perulus (286), the range of which is given as Panama to
Lobitos, Peru. This Peruvian species was described as
differing from P. (O.) vogdesi in its smaller size and thinner
texture as well as “by its lower convexity of the right
valve, its lower umbone which does not rise above the
hinge margin and by its sulcated or mesially grooved ribs.
The left valve differs by its wider, more flaring sub-
margins and especially by its narrower ribs, and much
wider interspaces, each carrying an intercalary riblet.”
Specimens of P. perulus in the collections of the California
Academy of Sciences collected by Dr. Robert Hoffstetter
(287) (who called attention to differences in the shell
characters of this southern species and those of P. vogdesi)
from Santa Elena, Ecuador, are purplish in color and
smaller than P. (O.) vogdesi. The largest, a left valve, is
39.5 mm long. Other similar specimens were collected
in Peru by Dr. Don L. Frizzell. The ribs on the right
valves are shallowly sulcated near the ventral margin.

SUBGENUS PATINOPECTEN DALL

Patinopecten Dall, Trans. Wagner Free Inst. Sci., Vol. 3,

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Pt. 4, p. 695, April, 1898. “Type P. caurinus Gld.” —
Arnold, U. S. G. S., Prof. Paper 47, p. 48, 1906.
“Type P. caurinus Gould.” — Grau, Allan Hancock Pac.
Exped., Vol. 23, p. 145, 1959. Type species Pecten
caurinus Gould. — MacNeil, U. S. G. S., Prof. Paper
354-J, p. 225, 1961. “Type: Pecten caurinus Gould.”
— MaeNeil, U.S. G.S., Prof. Paper 553, p. 40, 1967.

Type species (by original designation). — Pecten
caurinus Gould [Proc. Boston Soc. Nat. Hist., Vol. 3,
p. 345, December, 1850. “Hab. Port Townsend, Admiralty
Inlet, Oregon.” [Washington.] — Gould, U. S. Explor.
Exped. (Wilkes), Vol. 12, p. 458, 1852; atlas pl. 42, figs.
569, 569a, 569b, 1856. Original locality cited. — Arnold,
1906, p. 101, pl. 38, figs. 1, 1a, 1b; pl. 39, figs. 1, 2.
Pliocene to Recent. — Grau, 1959, p. 145, pl. 54, 1959.
Range: Channel Inlet, Orca Inlet, Cordova, Alaska, to
Point Reyes, California].

Range. —?Late Oligocene; early Miocene to Recent.
Recent from central California to Japan. In about 18 to
91 meters (10 to 50 fathoms).

Description. — Shell large, nearly equilateral, rather
flat, right valve slightly more convex than the left; ribs
on the right valve flat and sometimes dichotomous, those
on the left valve smaller and rounded; radial striae absent
or inconspicuous; ears subequal, the right anterior one
with a byssal notch; hinge nearly smooth, auricular den-
ticles often present. (Adapted in part from Dall.)

Remarks. — Two specimens of a fossil Pecten from
beds considered to be of middle Oligocene age in western
Oregon were referred to Patinopecten by Schenck (288).
These specimens are incomplete and poorly preserved and
we are not certain whether or not they are referable to
that taxonomic unit. MacNeil stated that the earliest
American species of Patinopecten is known from beds of
late Oligocene or early Miocene age in Alaska. This sub-
genus is represented in beds of middle Miocene age in
Washington, Oregon, and California by Pecten (Patino-
pecten) propatulus Conrad and two varieties of that species
have been described from central California. Pecten
caurinus Gould and P. oregonensis Howe occur in beds of
Pliocene age and the former also occurs in the Pleistocene
and Recent. Several west American species formerly
placed in Patinopecten were later referred to Lituyapecten
MacNeil.

In Japan, Akiyama (289) referred 33 species to
Patinopecten which he considered to be a genus ranging
from late Oligocene to Recent, and _ he placed five others
in a new subgenus Masudapecten (290). The latter was
described as “‘allied to Patinopecten (s. str.), but can be
distinguished from the right valve with less elevated
radials and with conspicuous ctenolium and the left valve
with less conspicuous threads.”

Most of the Cenozoic pectens of Japan, formerly
assigned to Patinopecten, were recently placed by Masuda
(291) in four genera included in a new subfamily Forti-
pectininae. The species were distributed among Masuda-
pecten Akiyama (type, Masudapecten masudai Akiyama),
Kotorapecten Masuda (type, Pecten kagamianus Yoko-
yama), Mizuhopecten Masuda (type, Pecten yessoensis
Jay) and Nipponopecten Masuda (type, Pecten akihoensis
Matsumoto).

The taxonomic value of some of these genera may
be open to question, but we withhold judgment of them
because we have not studied large collections of Cenozoic

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

pectens from Japan.

Most workers have considered Pecten yessoensis
Jay, the type of Mizuhopecten (Masuda, 1963, p. 151), to
be closely allied to Pecten caurinus the type of Patino-
pecten. However, Mizuhopecten was differentiated from
Patinopecten chiefly “by its having no auricular crurae
with distal denticle, rounded, broad radial ribs and large
auricles with wide and shallow byssal notch”. A con-
sideration of these shell characters led Masuda to place
Mizuhopecten in the subfamily Fortipectininae.

Blanckenhornia von Teppner (292) has as type
species Pecten oweni Arnold (not of De Gregorio, 1884),
now known as Pecten lohri Hertlein, an early Pliocene
species in California, with dichotomous ribs. This species
and its descendant, Pecten healeyi, were apparently in-
habitants of comparatively warm water. These two later
Tertiary species with deeply medially sulcated ribs could
be segregated under the separate subgenus Blanckenhornia.
However, the degree of development of the medial
sulcation of the ribs varies with species and may be of
specific rather than of generic value. For this reason we
have placed Pecten healeyi, which occurs in the San Diego
Formation, in Patinopecten.

Jaworski (293) suggested a possible relationship of
Pecten oweni Arnold (P. lohri Hertlein) with the early
Jurassic Pecten bodenbenderi Behrendsen stock. Beh-
rendsen’s species is now assigned to the genus Weyla J.
Bohm (type, P. alatus von Buch) and the suggested relation-
ship with P. lohri is not evident from our research. The
cardinal laminae on the hinge of W. alata are well developed
and transversely grooved (see Jaworski, fig. 7).

Fortipecten Yabe and Hatai (294) includes a group
of Pliocene species occurring in the north Pacific from
Japan to Alaska. Typical forms of this group have thick
shells and decidedly convex right valves with the beak
overhanging that of the left valve.

Vertipecten Grant and Gale, was based upon Pecten
nevadanus Conrad (P. bowersi Arnold), a Miocene species.
This group of large chlamyds is quite distinct from
Patinopecten, differing especially in that the left valve is
more convex than the right one and is ornamented with
large, rounded, scaly, irregular ribs of which every third
or fourth usually is higher than the others.

Pecten (Patinopecten) healeyi Arnold
Plate 31, Figures 1, 4, 6, 7; Plate 33, Figure 9;
Plate 36, Figures 8, 9; Text Figure 9

Pecten expansus Dall, Proc. U. S. Nat. Mus., Vol. 1, pp.
11, 14, 1878. Later Tertiary of San Diego. — Dall,
Proc. U. S. Nat. Mus., Vol. 1, p. 28, 1878. ‘‘well-
digging in stratum B2”, San Diego; p. 29, ‘‘(stratum C)”
“about ten miles northward from San Diego, on the
seacoast of California”. — Orcutt, West Amer. Sci.,
Vol. 6, Whole No. 46, p. 87, 1889. Dall’s record (1878)
cited. — Cooper, Calif. State Min. Bur., Bull. No. 4,
p. 31, 1894. “Pl. — San Diego.” — Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 63, 1903. ‘‘Pacific Beach.”
Pliocene. — Orcutt, quoted by Ellis in Ellis and Lee,
U. S. G. S., Water Supply Paper 446, p. 60, 1919.
Dall’s record (1878) cited.

Not Pecten expansus Smith, Quart. Jour. Geol. Soc.
London, Vol. 3, pp. 413, 419, pl. 18, fig. 21, 1847.

Pecten (Patinopecten) expansus Dall, Dall, Trans. Wagner

183

Free Inst. Sci., Vol. 3, Pt. 4, p. 706, pl. 26, fig. 1,
April, 1898. ‘“‘Pliocene of Pacific Beach (lower
horizon), near San Diego, California.”” — Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 108, 1903. “Pliocene. —
Pacific Beach, San Diego (Hemphill; Dall; Hamlin;
Arnold).”” — Schuchert, Dall, et al., U. S. Nat. Mus.,
Bull. 53, Pt. 1, p. 487, 1905. ‘Pliocene. Near San
Diego, California.”

Pecten (Patinopecten) healeyi Arnold, U. S. G. S., Prof.
Paper 47, pp. 28 (as Pecten healeyi), 103, pl. 36,
figs, 1, la; pl. 37, figs. 1, la, 2, 1906. “San Diego
formation (Pliocene), Pacific Beach, San Diego County,
Cal.”; “Tiajuana, Mexico (A. W. Greeley)”; also
“Purisima formation (lower Pliocene), near San
Gregorio, San Mateo County, Cal.”” — Arnold, in
Eldridge, U. S. G. S., Bull. 309, p. 240, pl. 34, fig. 1,
1907. Type. “San Diego formation (Pliocene), San
Diego County.” — Arnold and Anderson, U. S. G. S.,
Bull. 322, p. 154, pl. 26, figs. 1, 2, 1907. “San Diego
formation (Pliocene), Pacific Beach, San Diego County,
Cal.”” — Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 196, pl. 6, figs. 2a, 2b, 1931. Pacific
Beach. “Middle Pliocene.’ Earlier records cited of
Dall and others from San Diego. — Hanna and Hertlein,
Calif. State Div. Mines, Bull. 118, Pt. 2, p. 176, fig. 3,
1941. ‘Pacific Beach, San Diego, California. San
Diego formation, middle Pliocene.” — Hertlein and
Grant, Calif. Jour. Mines Geol., Rept. 35 State
Mineral., p. 69, 1939. Gray sandstone overlying the
basal conglomerate “about 1,200 feet south of the west
end of Law Street.” Pacific Beach, Pliocene. — Hert-
lein and Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2,
Pt. 1, p. 59, 1944. “bottom (60 feet) of David
Smalleomb’s well just north of the Mexican Boundary,
in the bottom of Matadero Canyon, four-tenths of a
mile west of the United States-Mexico Boundary monu-
ment No. 256,” Pliocene. — Keen and Bentson, Geol.
Soc. Amer., Spec. Papers No. 56, p. 87, 1944. Earlier
records cited. — Hertlein and Grant, Calif. State Divis.
Mines, Bull. 170, Chap. 2, p. 60, 1954. “San Diego
formation,” Pliocene. — Moore, San Diego Soc. Nat.
Hist., Occas. Paper 15, p. 46, pl. 21, figs. a, b, 1968.
Pacific Beach, Pliocene.

P[ecten]. californicus Cossmann and Peyrot, Actes Soc.
Linn. de Bordeaux, Tom. 68 (Conch. Néog. de Il’ Aqui-
taine, Tom. 2, Livre. 2 et Suppl.), p. 292, August 1,
1914. New name for Pecten expansus Dall, 1878.
“fossile du Pliocene de Californie.”

Not Pecten californicus Gabb, 1864. California, Cretaceous.

Pecten healeyi Arnold, McLaughlin and Waring, Map
Folio accompanying Bull. 69, inside of back cover,
species 42, pl. 1, fig. 42, 1914 (1915). “Etchegoin (San
Diego) formation of Pacific Beach, San Diego Co.,
California.” — J. P. Smith, Calif. State Min. Bureau,
Bull. No. 72, p. 38, 1916. ‘San Diego and lower
Fernando formations of the coastal region of southern
California.” — J. P. Smith, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 9, No. 4, pp. 150, 151, 1919. ‘“‘San Diego.”
Pliocene. — Hertlein, Stanford Univ. Bull., Ser. 5,
No. 78, pp. 83, 84, 85, 1929. “San Diego Pliocene.”
— Hertlein and Grant, Calif. State Div., Mines, Calif.
Journ. Min. Geol., Rept. 35 of State Mineral., pp.
69, 70, 71, 1939. Dall’s record (1874) cited. Also
“South slope of Soledad Mountain’; “David Small-

184

comb’s well just north of the Mexican boundary and
west of Tijuana, Mexico.” — Hertlein and Grant, Mem.-
San Diego Soc. Nat. Hist., Vol. 2, Pt. 1, pp. 56, 57, 59,
1944. “India Street, particularly at the corner of Upas
Street:” “thirty to forty feet above the base of the
section” at Pacific Beach; also “south sloping spurs of
Mount Soledad”; “near the Mexican Boundary about
three-quarters of a mile from the sea,” Pliocene. —
Milow and Ennis, 57th Ann. Mtg. Cordilleran Sec.
Geol. Soc. Amer., Field Trip Guidebook San Diego
Co. — 1961, p. 28, 1961. “San Diego Formation.”

Patinopecten healeyi Arnold, Woodring, Stewart, and
Richards, U. S. G. S., Prof. Paper 195, table opp. p.
112, 1941. “Strata at Pacific Beach,” “San Diego,”
Pliocene. Also see Stewart, p. 92, “Pliocene at San
Diego.”” — Woodring, U. S. G. S., Prof. Paper 222, p.
104, 1950. “Pacific Beach and inland,” Pliocene. —
Vedder, U. S. G. S., Prof. Paper 400-B, p. B327, 1960.
“San Diego formation.” Also Niguel Formation and
others. — Masuda, Trans. Proc. Palaeont. Soc. Japan,
New Ser., No. 52, pp. 147 (in text), 152, pl. 23, figs.
2a, 2b, 2c, 1963. “Loc. Rose Canyon, La Jolla
Quadrl., San Diego, California, U. S. A. Pliocene.”
— Glibert and Van de Poel, Mém. Inst. Roy. Sci. Nat.
Belgique, Deuxiéme Ser., Fase. 78, p. 22, 1965 (as
Patinopecten (s. s.) healeyi). Pacific Beach, San Diego,
California, Pliocene.

Type specimen. — No. 148012, United States
National Museum.

Type locality. — “San Diego formation (Pliocene),
San Diego County, Cal.”

Range. — Middle Pliocene, from Ferndale quad.,
California (Ogle), to Cedros Island and Bahia Tortolo
(Turtle Bay), Lower California, Mexico.

Occurrence in San Diego Fm. — C.A.S. 104, 105,
547, 957, 1130, 1135, 1138, 1177, 1178, 1179, 1181,
1182, 1183, 1186, 1199, 1399, 1400, 1401, 1404, 1413,
1414, 1418, 1419, 28158, 28453, 28454. L.A.M. 107,
122, 127, 305, 305A, 309, 318, 1132, A1323. S.D. 5,
10, 17, 21, 24, 27, 36, 37, 80, 88, 150, 331, 365, 402,
403, 404, 408, 417, 6304. U.C. A-8333. U.C.L.A. 294,
295, 298, 299, 300, 302, 309, 310, 312, 1384, 1385,
2359, 2420.

Original description. — Shell averaging about 130
millimeters in altitude, length about equal to height,
inequivalve (the right slightly more ventricose than the
left), equilateral, and with smooth margins; base evenly
rounded; sides only slightly concave above. Right valve
somewhat ventricose, and ornamented by 18 to 21 strong,
squarish, sub-equal primary ribs, which become more or
less dichotomous, and sometimes trichotomous, after 30
or 40 millimeters in length; medial sulcus of rib more or
less deep, in some cases being as deep as the interspaces
near the ends, thus completely dividing the primary rib;
interspaces subequal, much narrower than the ribs, quite
deeply channeled, and often ornamented by a small,
rounded intercalary riblet; whole surface crossed by
numerous fine lines of growth; hinge line less than one-
half length of disk; anterior ear only slightly longer than
left, arcuate in front, and ornamented by several obsolete
radial ridges and numerous sharp incremental lines; byssal
notch quite prominent; posterior ear slightly obliquely
truncated, and ornamented by sharp incremental lines
and sometimes by obsolete radiating ridges. Left valve

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Text Fig. 9.
Hypotype (Cat. No. 1950, University of California at Los
Angeles), from Pacific Beach, San Diego; Pliocene. Length

Pecten (Patinopecten) healeyi Arnold.

130.8 mm. A. Right valve. B. Left valve.

E. H. Quayle.)

(Drawn by

much compressed; ribs narrow and rounded, more or less
sharply toward the top (there being in some cases a nar-
row, slightly raised line along the top); interspaces wide,
and each ornamented by a more or less prominent,
rounded, intercalary riblet; whole surface striated con-
centrically by fine, sharp, wavy lines; ears obliquely
truncated and sculptured similarly to those of the right
valve. (Arnold.)

Dimensions. — Alt. 112 mm; long. 112 mm; hinge
line, 50 mm; diameter 18 mm. (Arnold.)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Remarks. — This large, rather flat pecten is easily
recognized by its flat-topped, medially sulcated radial ribs
on the right valve and the rounded ribs with an inter-
calary in each interspace on the left valve. Pecten healeyi
occurs at nearly every locality where fossils are found in
the San Diego Formation in and near San Diego, California.

Juvenile specimens are smooth in the early stage
but usually radial undulations of the anterior margin begin
to form after the shell has attained a height of 3 to 5 mm.
Occasionally specimens remain smooth up to a height of
23 mm. The ribs on the right valve, especially those
toward the anterior and posterior margins, begin to develop
a slight medical sulcus after the shell has attained a height
of 10 mm, but such sulcations on the medial ribs are well
developed only after a height of 30 to 40 mm has been
attained. Occasionally the ribs on large specimens may
bear two sulcations which thus divide the major ribs into
three small riblets, but such forms, so far as known, have
no taxonomic significance. One such right valve with a
strong intercalary in each interspace from Pacific Beach
in the collections of the San Diego Society of Natural
History, is 165 mm high. The largest specimen of Pecten
healeyi seen by us is one collected by G. P. Kanakoff from
Loc. 107 (LAM), end of Arroyo Drive, San Diego, which
is 222 mm long and 195 mm high. The hinge (incom-
plete) of a portion of a left valve in the same institution
collected by Roy L. Moodie at Pacific Beach, is 99 mm
long. The shell on lateral areas of the umbonal portion is
6 mm thick.

A low, narrow ridge is present on each side of the
ligamental pit. The umbonal portion of the interior of
many valves is covered with a layer of calcareous
material, the weathered surface of which reveals a net-
work of many fine, irregularly arranged plates or cells.

Pecten healeyi appears to be a descendent of Pecten
lohri Hertlein (295) as mentioned by Arnold. He pointed
out that some forms occurring in the Purisima Formation
in San Mateo Co. (296), California, appear to be inter-
mediate between Pecten healeyi and Pecten lohri in their
respective lowest and highest stratigraphic ranges.

The stratigraphic ranges of these two species have
been well defined by Woodring in the Santa Maria district,
Santa Barbara Co., California. In that district Pecten
lohri occurs questionably in diatomaceous strata of un-
certain age and in the overlying Todos Santos Claystone
and in the Tinaquaic Sandstone, the latter two of early
Pliocene age. Overlying these are the Foxen Mudstone
and Careaga Sandstone in which Pecten healeyi occurs.
These are of approximately middle Pliocene age.

Compared to Pecten healeyi, the shell of Pecten
lohri is smaller, more convex, has fewer (14 to 16) and
coarser ribs on the right valve and it has a longer hinge
line. The medial sulcations on the ribs begin nearer the
dorsal margin than they doon P. healeyi, and the inter-
calary ribs are coarser.

Pecten healeyi and P. lohriare Pliocene members of a
group which includes Pecten propatulus Conrad (297),
described from mid-Miocene strata at Astoria, Oregon, and
the only slightly different varieties described as P. hay-
wardensis Lutz (298) and P. haywardensis calaverasensis
Hall (299) from mid-Miocene strata in central California.

Pecten healeyi is quite distinct from P. propatulus
and differs in the more numerous and more deeply
sulcated ribs on the right valve, finer ribs on the left valve

185

and smaller byssal fasciole beneath the right anterior ear.
Pecten oregonensis Howe (300), described from Pliocene
beds at Coos Bay, Oregon, is said to differ from P. pro-
patulus in the higher ribs, wider umbonal angle, and in
other details.

Pecten tryblium Yokoyama (301) from the late
Miocene and Pliocene of Japan bears a resemblance to P.
healeyi but is longer in proportion to the height, the ribs
on the right valve appear to be proportionally narrower
and the hinge line is longer.

Pecten yamasakii Yokoyama (302) was placed
questionably in the synonymy of Pecten healeyi by Grant
and Gale, and Kuroda (303) placed it as a subspecies of
P. healeyi. The Japanese species is said to possess 19 to 22
tripartite ribs on the medial portion and bipartite ribs
on the anterior and posterior portions of the right valve.
A subspecies, Pecten yamasakii ninohensis Masuda (304)
is another member of the Japanese group. These oriental
forms differ sufficiently from the west American fossils
to constitute distinct species. They were placed in the
genus Kotorapecten by Masuda in 1963.

Pecten duplex Cooke (305) described from beds of
mid-Tertiary age on the island of Antigua in the Caribbean
Sea, was compared by its author with Pecten healeyi.
The Caribbean form has medially sulcated ribs on the right
valve but it is said to be smaller and the ribs on the left
valve are square-topped and bear a shallow medial groove.
This latter feature is reminiscent of Pecten yakatagensis
Clark (306) which was described from strata of Pliocene
age in southeastern Alaska but the two are not closely
related. Olsson and Richards assigned the Antiguan
fossil to Flabellipecten. The form illustrated by Manning
and Ogle under the name of “Pecten oregonensis Howe
var.”” (307) from Boulder Creek near Ferndale, California,
also has square-topped medially grooved ribs on the left
valve. It was described later by MacNeil as Patinopecten
(Lituyapecten) falorensis (308).

Pecten healeyi is an index fossil of the San Diego
horizon, middle Pliocene, of California and northern
Lower California. It has been reported from many
localities from Ferndale, northern California, to Cedros
Island and Bahia Tortolo (Turtle Bay), Lower California,
Mexico. Also from Santa Cruz Island, California.

This species lived in warm water unlike its northern
relative Pecten caurinus Gould which followed it in
stratigraphically later Pliocene and Pleistocene beds in
California.

[Pecten (?Patinopecten) merriami Arnold]

Pecten (Pecten) merriami Arnold, U. S. G. S., Prof.
Paper 47, p. 99, pl. 30, figs. 1, 1a, 2, 1906.

P[ecten]. merriami Arnold, J. P. Smith, Calif. State Min.
Bureau, Bull. No. 72, p. 38, 1916. “San Diego and
lower Fernando formations of the coastal region of
southern California.”’ Pliocene.

Type specimen. — Number 12086, University of
California, Museum of Paleontology.

Type locality. — “from light-colored shale under-
lying the conglomerate on San Felician Creek, near Piru,
Ventura County,” California. ‘‘Pliocene (lower).”

Range. — Probably middle or late Pliocene.

Remarks. — The only record of occurrence of Pecten
merriami in the San Diego Formation is the equivocal one

186

of J. P. Smith. We have not seen any specimens from the
Pliocene beds at San Diego which could be referred to this
species.

We have examined a cast of the holotype, No.
6100 (Calif. Acad. Sci. Dept. Geol. Type Coll.), and we
can add but little to Arnold’s discussion of this species.
The hinge on the type specimen is lacking as is the shell
on most of the umbonal area. A few ribs on the lateral
areas are slightly but definitely medially sulcated. The
taxonomic status of this species is uncertain.

SUBGENUS LITUYAPECTEN MACNEIL
Lituyapecten MacNeil, U. S. G. S., Prof. Paper 354-J,

p. 227, 1961.

Type species (by original designation). — Patino-
pecten (Lituyapecten) lituyaensis MacNeil [1961, p. 231,
pl. 39, figs. 1, 3; pl. 40, figs. 1-5; pl. 41, fig. 1; pl. 42,
figs. 1, 2, 4; pl. 43, figs. 1-4. “Type locality. — Upper
mudstone unit of unnamed upper Tertiary formation,
about 300 to 340 feet above the base of the upper mud-
stone unit, southwest of Cenotaph Island, Lituya Bay,
Alaska, USGS M270”. Pliocene].

Range. — Late Oligocene (Poul Creek Formation)
or early Miocene, to middle Pliocene, Alaska; Pliocene of
Washington, Oregon, California, and northern Lower
California, Mexico.

Description. — “‘The new subgeneric name, Lituya-
pecten, is here proposed to include the species of Patino-
pecten having one to several rows of frill-like flanges on
the ribs of the left valve” (MacNeil, 1961, p. 228).

Remarks. — This group of scallops is generally
referred to Patinopecten in earlier works. In support of
possible relationship with Patinopecten, MacNeil reported
the presence of small frill-like flanges close to the beak
the ribs of some left valves of Pecten (Patinopecten)
propatulus. The same author pointed out the difficulty of
identification based only on right valves which may be
similar in some members of Lituyapecten though the left
valves may be quite dissimilar.

The ribs on the left valves of several species in this
group are high, narrow and flat-topped, those on the right
valve, flat-topped or rounded and often undercut on the
sides. In addition to the frill-like flanges on the ribs,
concentric microsculpture is present on the valves.
MacNeil mentioned that the fine imbricating microstructure
present on many specimens of Patinopecten and Swifto-
pecten was not observed by him on any specimens of
Lituyapecten.

Seven species from the medial Tertiary of western
North America were assigned to Lituyapecten by MacNeil.
One of these is present in the San Diego Formation.

Pecten (Lituyapecten) dilleri Dall
Plate 35, Figures 4, 7

Pecten (Lyropecten) dilleri Dall, Nautilus, Vol. 14, No.
10, p. 117, February, 1901.

Pecten (Patinopecten) dilleri Dall, Arnold, U. S. G. S.,
Prof. Paper 47, p. 62, pl. 5, fig. 2, 1906. Rio Dell,
Eel River, Humboldt Co., California. ‘““Upper Miocene
or lower Pliocene”. — E. K. Jordan and Hertlein,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 431,
pl. 30, fig. 1, 1926. Near Elephant Mesa, Lower

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

California, Pliocene. Also earlier records.

Patinopecten dilleri Dall, Woodring, in Woodring and
Bramlette, U. S. G. S., Prof. Paper 222, pp. 65, 83,
84, 106, 107, pl. 11, figs. 1, 9, 1950. Santa Maria
district, California, Pliocene. Also p. 104, “India and
Upas streets, San Diego.’ — Vedder, U. S. G. S., Prof.
Paper 400-B, p. B327, 1960. “San Diego formation.”
Also Niguel Formation and others.

Type specimen. — “Cotype” No. 164846, United
States National Museum. (Arnold.)

Type locality. — “horizon of Rio Dell on the Eel
River, California.” (Dall.) According to Keen and
Bentson (Geol. Soc. Amer., Spec. Papers No. 56, p. 85,
1944), syntypes of this species are from the “[W 1/2 5,
T 1N, R 1E, H], Humboldt Co.”’ A study of the strata in
the area from which the type of Pecten dilleri came led
Ogle (309) to the opinion that “it suggests that the type
must have been found in the lower part of the Rio Dell
formation.”

Range. — Middle Pliocene, California, and northern
Lower California, Mexico. “ef.” Lituya Bay, Alaska, late
Tertiary (MacNeil, 1961).

Occurrence in San Diego Fm. — U.C.L.A. 307.

Original description. — Shell large, rather compressed,
nearly orbicular with a relatively short, straight hinge-line,
dorsally rectangular, nearly smooth, subequal ears, the
posterior with three small riblets; a well marked though
shallow byssal fold; and moderately thick valves. The
right valve is somewhat more convex and strongly sculp-
tured, bearing 29-30 high, narrow, T-rail-shaped ribs,
flattened above, overhanging narrower, deep, nearly
smooth channels; and with marked concentric imbrication,
feeble on top of the ribs but articularly scaly at their
sides. The sculpture of the left valve is less pronounced,
hidden in the matrix, but apparently similar. Alt. 192,
lat. 175, diam. about 35 mm. The lateral edges are
slightly defective, the submargins very narrow. (Dall.)

Remarks. — One well preserved specimen found in
the San Diego Formation is present in the collections of
the University of California at Los Angeles. The record
of Pecten dilleri from San Diego by Woodring was based
upon this specimen. It is 88.6 mm long, 88.6 mm high
(anterior margin slightly defective), convexity (both
valves together), 17 mm. There are 27 radial ribs of which
two nearest the anterior margin on the right valve are
medially grooved. The riblets on the anterior ears are fine
but well defined, those on the posterior ears only faintly
indicated. Scaly concentric lamellae are only faintly
noticeable on the right valve but on the left valve these
are well developed. A portion of a right valve, 61 mm
long, is present in the collection from Loc. 307 (UCLA).

On some specimens of this species from other
formations, concentric lamellae may cross the ribs or only
flanges may be present along the margins of the ribs on
the right valve. On well preserved left valves, strong,
elevated, concentric lamellae cross the ribs, or are
occasionally interrupted and alternating, as shown on the
illustrations of a left valve from northern Lower California
by E. K. Jordan and Hertlein (1926, pl. 30, fig. 1).

A study of the species of Lituyapecten led MacNeil
(1961, pp. 233, 235) to conclude that P. (L.) dilleri
probably stems from P. (L.) poulcreekensis MacNeil
(310), which was described from the upper portion of the
Poul Creek Formation in Alaska of early Miocene age. He

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

discussed and illustrated specimens (see MacNeil, 1961,
p. 235, pl. 41, figs. 4, 5; pl. 45, fig. 1) under the name of
“Patinopecten (Lituyapecten) cf P. (L.) dilleri (Dall),”
“from the upper mudstone unit of an unnamed Tertiary
formation, Lituya district, Alaska, USGS 7931,” of
Pliocene age.

Akiyama suggested possible relationship between
P. (L.) dilleri and P. kurosawaensis Yokoyama (311)
which was described from beds of late Pliocene age in
Japan. That species is said to bear 36 to 40 round-topped
ribs. No mention is made in the description of any frill-
like flanges on the ribs, a shell character well developed
on P. (L.) dilleri. Evidence of close relationship between
the Japanese species and P. (L.) dilleri needs confirmation.

Pecten (Lituyapecten) purisimaensis Arnold (312),
another member of the P. (L.) poulcreekensis group, is
characterized by fewer (22 to 24), usually broader ribs on
the right valve and narrower, sharper ribs with cor-
respondingly wider interspaces on the left valve.

Fossils cited as “P. dilleri variety” by Woodring
(1950, pl. 9, figs. 6-8), from the Sisquoe Formation in the
Santa Maria district are characterized by the presence of
riblets in the interspaces on the left valve and by minute
riblets crossed by very fine lamellae in the interspaces on
the right valve.

Pecten dilleri Dall was recorded by Arnold and
Hannibal (313) as occurring in strata of Pliocene age in
western Washington but Weaver (1943) later cited P.
coosensis from beds of that age in both western Washing-
ton and Oregon.

Pecten (Lituyapecten) coosensis Shumard (314),
bears a resemblance to P. (L.) dilleri in the slightly
developed flanges on the ribs and in that the ribs bear one
or more medial grooves toward the ventral margin, a
feature well shown in the illustrations by Weaver and by
Trumbull. Also a fold is present on the anterior ear of the
left valve. MacNeil (1961, p. 233) suggested that P. (L.)
coosensis is a member of the P. (L.) yakatagensis group.

Akiyama suggested that P. (L.) coosensis is closely
allied with P. nakatombetsuensis (315) a species said to
be sculptured with 29 elevated, flat-topped, squarish ribs
on the right valve and 24 round topped ribs on the left
valve, from the early Pliocene of Japan. Judging from the
description and illustrations only, the Japanese species is
quite distinct from P. (L.) coosensis.

Pecten dilleri has been recorded from California in
Humboldt Co., Santa Barbara Co., and San Diego Co., and
in Lower California northwest of Elephant Mesa. So
far as known, typical specimens of this species occur only
in beds of approximately middle Pliocene age.

GENUS CHLAMYS RODING IN BOLTEN

Chlamys Roding in Bolten, Mus. Boltenianum, Pt. 2, p.
161, 1798. Numerous species cited, the first two are,
“C. Cinnabarina. Dei zinoberrothe Mantel. Gmel.
Ostrea islandica. sp. 55. Chemn. 7.t.65. fig. 615, 616.
9 St.” and “C. islandica. Der islandische Mantel. eod.
4 St.” — Meek, Rept. U. S. Geol. Surv. Terr., Vol. 9,

p. 23, 1876. ‘‘P. Islandica, Linn . . . . this shell was
Bolten’s first species of Chlamys .... it has been cited
by Herrmannsen and others as its type.” — Woodring,

Carnegie Inst. Washington, Publ. 366, p. 64, 1925.
“Type (by subsequent designation, Dall, 1898). —

187

Pecten islandicus Miller.” — Arkell, Palaeontogr. Soc.
(London), Vol. 82, for 1928, Brit. Corall. Lamellibr.,
Pt. 2, p. 102, issued December, 1930. [No type cited. ]
— Cox, Mem. Geol. Surv. India, Palaeo. Indica, Ser. 9,
Vol. 3, Pt. 4, p. 3, 1952. “Genotype. — Pecten
islandicus Miller (1776, p. 248), Recent circumboreal;
designated by A. N. Herrmannsen, 1846.”

Not Chlamys Koch, 1801. Coleoptera. Renamed
Arthrochlamys by von Ihering, Rev. Mus. Paulista,
Vol. 6, p. 642, 1905.

Myochlamys von Ihering, An. Mus. Nac. Buenos Aires,
Vol. 14 (Ser. 3°, Vol. 7), p. 251, 1907. “Maintenant
cependant ayant verifié que les noms de Bolten ne
peuvent pas étre admis, je ne peux pas trouver un autre
nom generique pour Chlamys auct., et je propose par
cette raison le nom générique de Myochlamys n. n.,
pour substituer Chlamys Bolten.”

Chlamydina Cossmann, Rev. Crit. de Paleozool., Vol. 13,
Livr. 1, p. 67, January, 1909. New Name for
Myochlamys von Ihering, 1907, not Myochlamys Fair-
man, 1876. Coleoptera.

Type species (by subsequent designation, Herrmann-
sen, Indic. Gener. Malacozoor., Vol. 1, p. 231, 1846). —
“Typus: Pecten Islandicus Linn.’ [Miiller, Zool.
Danicae Prod., p. 248, 1776. “I. Horpudiskur. Isl. R. 901.
t. 10.f.5. edulis.” Illustrated by Chemnitz, Syst. Conchyl.-
Cab., Bd. 7, p. 314, pl. 65, figs. 615, 616, 1784. —
Arnold, U. S. G. S., Prof. Paper No. 47, p. 113, pl. 45,
figs. 1, la, 1906. These figures reproduced by I. S.
Oldroyd, “The Marine Shells of the West Coast of North
America,” Stanford Univ. Publ. Univ. Series Geol. Sci.,
Vol. 1, pl. 8, figs. 1, 2, 1924, and by Korobkov, Meto-
dicheskoe Rukovodstvo Po Tretichnym Molluskam.
Plastinchatozhabernye [Lamellibranchiata], Gostoptehiz-
dat [Publishing house], Leningrad, pl. 63, figs. 1a, 1b,
1954. See also discussion of this species by Jensen,
Danish Ingolf-Exped., Vol. 2, Pt. 5, p. 15, pl. 1, figs.
4a-d, 1912. Greenland, Iceland, and the Faroes; and
MacNeil, U. S. G. S., Prof. Paper 553, pp. 33-34, pl. 18,
fig. 8; pl. 19, figs. 2, 5; pl. 24, figs. 12, 13, 1967. ]

Range. — Early Triassic to Recent, worldwide.
Recent from low tide to about 2013 meters (1100
fathoms).

Description. — Shell suborbicular to subtrigonal and
higher than long, frequently slightly oblique, equivalve or
one valve slightly more convex. Auricles clearly delimited
from the body of the shell, unequal, the anterior ones
longer than the posterior. Byssal sinus present beneath
the anterior auricle; ctenolium usually developed. Cardinal
crura variable in number and strength; auricular crura
sometimes present, but seldom prominent. Ornamenta-
tion similar or dissimilar on the two valves, normally con-
sisting of radial threads or ribs and thin, concentric
lamellae which often form rough, scale-like projections,
especially on the left valve; ornamentation on some
species is almost obsolete or lacking; margin usually
scalloped. (Adapted from Arkell, 1930, and Cox, 1952.)

Remarks. — Chlamys, on the basis of shell charac-
ters, is here used as a genus name. It is recognized, how-
ever, that on the basis of similarity of anatomy, Chlamys
could be retained as a subgenus (316) of Pecten.

The genus Chlamys, in a broad sense, includes the
majority of known species of Pectinidae. These species
all possess a well developed byssal sinus but the ornamen-

188

tation varies from fine to coarse ribs or to mere undula-
tions of the shell to nearly smooth unsculptured valves.
Valves of some species of Chlamys which are nearly
smooth usually retain at least some ribbing on the auricles.
Some species attach themselves by a byssus to some object
and move about comparatively little. Others break the
attached threads and swim about freely. Some large forms
lie upon the sea-bottom and in the adult stage, apparently
move about but little if any. Many of the Recent species
are brilliantly colored.

There is great variation in the ribbing of the
Chlamys group as shown by Fedotov’s (317) study of
Recent and fossil forms of Chlamys islandica.

SUBGENUS CHLAMYS S.S.

Range. — Early Triassic to Recent.

Description. — Shell usually with the dorsal margins
of the body steeply sloping and the height greater than
the length; not strongly inflated. Byssal notch deep,
ctenolium well developed. Ornamentation similar or
slightly dissimilar in the two valves, consisting of close-set
radial threads or narrow ribs, which are frequently
squamose. About two pairs of not very prominent
cardinal crura are present. (Cox, 1952.)

Remarks. — Ribbing on the two valves in this group
is usually dissimilar, those on the right valve usually in-
crease by dichotomization, those on the left valve by
intercalation. The two valves are gently convex, some-
times the left one more so than the right one. Arkell
called attention to the fact that the “internal ribs near the
margin are rounded, grooved and not very prominent.”

As pointed out by others, the fine, spiny ribbed
forms resemble, in many features, the late Paleozoic
Aviculopectinidae. They are well represented both as
fossils and Recent in western North America.

Some of the characters of the shell of Chlamys s. s.
which differ from those of the subgenus Aequipecten
Fischer are the greater height than length, smaller apical
angle, more numerous often bifurcating radial ribs and
the unequal auricles. Arkell (1930, p. 102) mentioned
that in Aequipecten “‘the ribs are usually fewer and far
more regular, not bifurcating, while the internal ribs near
the margin are prominent, flattened and marginally

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

pointed.” Furthermore, the inner surface of the valves of
Chlamys, except near the margin, is rippled, whereas that
of Aequipecten has clearly defined ribs.

It is difficult, however, to determine whether some
species should be assigned to the subgenus Chlamys s. s.
or to Aequipecten. Staesche (1926, p. 26) believed that
various groups of species referable to Aequipecten arose
independently from time to time from Chlamys. He (318)
assigned 25 forms from the Schwabian Jurassic to
Chlamys and eight to Aequipecten. From the Jurassic
of France, Dechaseaux (319) assigned 25 forms to
Chlamys and 32 to Aequipecten. Some of these are now
placed in different subgenera.

From a study of Recent species Dechaseaux (1936,
p. 126) inferred that the presence of Chlamys in a fauna
indicated proximity to a rocky bottom.

Chlamys (Chlamys) hastata Sowerby
Plate 33, Figures 4, 5, 6

P[ecten]. hastatus Sowerby, Thes. Conch., Vol. 1, p. LA
pl. 20, fig. 236, 1842. — Dall, Proc. Calif. Acad. Sci.,
Vol. 5, p. 297, 1874. “Pliocene.” ‘‘well at San Diego.”
— Dall, Proc. U. S. Nat. Mus., Vol. 1, p. 28, 1878.
“Well-digging in stratum B?” San Diego. — Cooper,
Calif. State Min. Bur. Seventh Ann. Rept. State Mineral,
p. 257, 1888.‘‘PI. — San Diego well.” — Orcutt, West
Amer. Sci., Vol. 6, Whole No. 46, p. 85, August, 1898.
Dall’s record (1874) cited. — Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 63, 1903. “Pacific Beach,”
Pliocene. — Arnold., U. S. G. S., Prof. Paper 47, p. 28,
1906. “San Diego formation” at “Pacific Beach.” —
J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 3,
pp. 173, 182, 1912. “San Diego-Purisima.” — J. P.
Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4,
p. 151, 1919. “San Diego,” Pliocene. — Orcutt,
quoted by Ellis in Ellis and Lee, U. S. G. S., Water
Supply Paper 446, p. 59, 1919. Dall’s record (1874)
cited. — Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 53, pl. 29, figs. 1, 3, 1924.
“Range. Monterey to San Pedro, California.”

Pecten (Chlamys) hastatus Sowerby, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 109, pl. 11, figs. 4, 4a (Pliocene,
.Deadman Island’’), 1903. ‘“‘Pliocene . . . San Diego

Key to Species and Subspecies of Chlamys s. s.

A. Interspace with minute radial
or oblique groovings

a. Interspaces with fine radial
grooves; ribs even, fine, low
aa. Interspaces with minute
oblique groovings; major ribs
consisting of a fascicule
of three riblets

opuntia

b. Each fascicule with central
riblet higher and with very
long spines ee

bb. Each fascicule with three
riblets of nearly equal
height with spines of
moderate height .

hastata

herictus

B. Interspaces with minute reticulate,
honeycomb-like sculpture

a. Major ribs on right valve com-
posed of 3 fascicules of nearly
equal riblets mney

aa. Major ribs on right valve simple,
flattened on top

ellisi

b. Ribs on left valve simple, not
fasciculated or imbricated;
ribs with honeycomb-like
SCUlpture geen. une ee

bb. Ribs on left valve often
fasciculated and imbricated;
top of ribs usually lacking
honeycomb-like sculpture .

jordani

rubida

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

(Arnold). — Arnold, U. S. G. S., Prof. Paper 47, p.
108, pl. 41, fig. 4 (““Pliocene, San Raphael Hills, Santa
Barbara County, Cal.”’); pl. 42, figs. 1, 1a, 2, 2a (Recent
Monterey Bay, California, 1906. “Pliocene. . . Pacific
Beach, San Diego (Arnold, — Waterfall, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 18, No. 3, table opp.
p. 78, 1929. “San Diego Pliocene.”

Pecten (Pecten) hastatus Sowerby, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 166, pl. 11, figs.
6a, 6b, 1931. Page 167. “San Diego (Dall, 1874)’,
“Pliocene.”

Chlamys hastata Sowerby, Grau, Allan Hancock Pac.
Exped., Vol. 23, p. 84, pls. 27, 28. 1959. Monterey to
San Diego, California, Recent. Also Pliocene and
Pleistocene.

Mimachlamys hastata Sowerby, Glibert and Van de Poel,
Inst. Roy. Sci. Nat. Belgique, Mém., Deuxieme Ser.,
Fase. 78, p. 31, 1965. Spanish Bight (North Island),
California; Pleistocene.

Type specimen. — “‘The only specimen we have seen
is in the collection of the Rev. F. J. Stainforth.”
(Sowerby.) Location of type specimen unknown to the
present authors.

Type locality. — No locality originally cited.
Subsequently designated by Grau (1959, p. 85) as “San
Diego, California.”

Range. — Late Miocene (Nomland; Stanton (cf.);
Addicott and Vedder); Pliocene to Recent. Recent from
Monterey to San Diego, California, in 18 to 91 meters
(10 to 50 fathoms).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 105, 1132, 1400, 2028, 28892. L.A.M.
107, 122, 305. S.D. 34, 2915. U.C.L.A. 294, 2420.

Original description. — T. ovali subtrigona, sub-
elongata, scabra; auriculis inaequalibus, posticis minimis,
anticis magnis, scabroso-sulcatis: valva sinistra, costis 8,
inaequalibus, valde elevatis, angulatis; spinas numerosas,
erectas, subcrispatas ferentibus. Costis interstitialibus
numerosis, inaequalibus, serratis: valva dextra, costis 22,
angulatis, spinosis; colore rubro, intus albo. Long. 0.95;
lat. 0.30; alt. 1.15; poll. (Sowerby.)

Oval, inclining to triangular, rather elongated, rough;
with very unequal ears, the posterior ones being very
small; the upper valve has eight unequal, elevated, angular
ribs, with numerous erect, slightly curved sharp spines, and
several smaller spinose ribs in the interstices. The lower
valve has 22 more nearly equal ribs with more numerous
and smaller spines on the angles. (Sowerby.)

Remarks. — This spiny scallop occurs in strata of
Pliocene age at Pacific Beach as well as on the San Diego
mesa. The largest specimen from that area which we have
seen is a right valve from Loc. 2028 (CAS), Pacific Beach.
It is 43.2 mm long and 48.5 mm high. Some of these
specimens retain details of sculpture typical of Chlamys
hastata with the prominent central riblet bearing long,
projecting spines.

Eroded specimens of this species are often difficult
to separate from similar specimens of the subspecies C.
hastata hericius. In general, the major ribs on C. hastata
are rather sharply defined whereas on C. h. hericius
these are composed of a fascicule of riblets the whole with
a convex outline. The right valve of C. hastata is sculptured
with 9 or 10 paired, high, steeply sloping ribs, each bearing
a row of long spines. There are 1 to 3 thread-like spiny

189

riblets in the interspaces. Very fine, incised groovings are
present on the surface in the interspaces between the
ribs. On the right valve of C. h. hericius, a generally more
northern, larger form, there are three riblets of nearly equal
size (although the central one is slightly larger) on each
major rib which lend a rounded appearance to the ribs.
The ribs on the left valve of C. hastata, 9 or 10 in number,
are narrower and more steeply sloping than are those of
C. h. hericius.

A large Recent specimen of Chlamys hastata in the
collections of the California Academy of Sciences is
60 mm long, 63.5 mm high (dorsal-ventral), the convexity
(both valves together), about 16.5 mm. The shells of this
species are beautifully tinted with pink or pinkish-white
or orange coloration. This scallop can either swim about
or may remain attached.

The species described as Pecten (Chlamys) lawsoni
(320) by Arnold was based upon a poorly preserved
specimen from “the Pliocene at the Waldorf asphalt mine,
4 miles south of Guadaloupe, Santa Barbara County”’, is
generally relegated to the synonymy of C. (C.) hastata.

Adegoke (321) recently mentioned that most of the
records of occurrences of C. hastata from the Santa
Margarita Formation, of late Miocene age, are probably
referable to species of Hinnites.

The fossil described under the name of Pecten
(Chlamys) hastatus var. ingeniosa Yokoyama (322) from
late Tertiary beds in Japan is a species distinct from the
west American shell. Likewise, the form indicated by
Slodkewitsch (323) as a questionable variety of C. hastata
from the upper horizon of the Kavran series of Pliocene
age in Kamtschatka is apparently not referable to Sowerby’s
species. Vaillant’s record of Pecten hastatus from Suez
later was referred by Lamy (324) to Chlamys squamosa
decoriata Jousseaume.

The species described as Pecten denticulatus by
Adams and Reeve (325), with the locality “Hab. Shores of
Borneo,” was believed by Bavay (326) to be a juvenile
form of Chlamys hastata and Grau (1959 , pp. 86-87) ac-
cepted this view. This assignment may be correct,
especially when considering the fact that some other
species described by Adams and Reeve as coming from the
East Indian region are now known to be west American
species. Cox (327), however, considered Bavay’s assign-
ment of Pecten denticulatus Adams and Reeve to Chlamys
hastata to be very improbable and proposed a substitute
name for the former, Chlamys odontata, because of a
prior Pecten denticulatus von Hagenow, 1842.

MacNeil (1967, pp. 14-15) recently discussed the
Chlamys (Chlamys) hastata group.

Chlamys (Chlamys) hastata hericius Gould
Plate 33, Figure 2

Pecten hericius Gould, Proc. Boston Soc. Nat. Hist., Vol.
3, p. 345, December 1850. — Gould, U. S. Explor.
Exped. (Wilkes), Vol. 12, p. 457, 1852. Atlas, Moll.,
pl. 42, figs. 570, 570a, 570b, 570c, 1856. “‘Inhabits
the Straits of De Fuca Oregon.” — Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 63, 1903. ‘“‘Pacific Beach’’,
“Pliocene”. — I. S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 52, pl. 7, figs. 1, 2, 1924.
(Copy of illustrations from Arnold, 1906, pl. 43, figs.
3, 3a). “Range. Port Althorp, Alaska, to San Diego,

190

California.”

Pecten hericeus Gould, Dall, Proc. U. S. Nat. Mus., Vol. 1,
pp. 11, 29, 1878. “San Diego,” “Later Tertiary.”
Page 29, “‘about ten miles northward from San Diego,
on the seacoast”’, “(Stratum C).”

Pecten hastatus Sowerby, Cooper, Calif. State Bur. Min.,
Seventh Ann. Rept. State Mineral., p. 257, 1888, (in
part, according to Arnold, 1906). “San Diego well,”
Pliocene. — Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 166, 1931 (in part, Pecten hericeus in
synon.).

Pecten (Chlamys) hericeus Gould, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 110, pl. 11, fig. 2 (‘“Pliocene,
Deadman Island”), 1903. “San Diego well (Cooper):
San Diego (Arnold).” — I. S. Oldroyd, Publ. Puget
Sound Biol. Sta., Vol. 4, p. 16, pl. 23, figs. 1, 2, 1924.
(Copy of Illustrations by Arnold, 1906, pl. 43, figs. 3,
3a). Port Althorp, Alaska, to San Diego, California. —
Waterfall, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol.
18, No. 3, table opp. p. 78, 1929. “San Diego
Pliocene.”

Pecten (Chlamys) hastatus Sowerby var. hericius Gould,
Arnold, U. S. Geol. Surv., Prof. Paper 47, p. 110, pl.
43, figs. 3, 3a (Recent, Puget Sound), 1906. “Pacific
Beach, San Diego (Hemphill, Arnold)”, “Pliocene.”

Chlamys hastata hericia Gould, Grau, Allan Hancock Pac.
Exped., Vol. 23, p. 87, pl. 29, 1959. Gulf of Alaska to
Santa Barbara, California, Recent. Also Pliocene and
Pleistocene.

Chlamys (““Chlamys”) hastata hericius (Gould), MacNeil,
U. S. Geol. Surv., Prof. Paper 553, p. 14, pl. hy figs.
Ue UES Puget Sound, Recent.

Type specimen. — No. 5955, United States National
Museum.

Type locality. — “Hab. Straits of De Fuca, Oregon.”

Range. — Late Miocene (Arnold); Pliocene to Recent.
Recent from Port Althorp, Alaska, to Santa Barbara,
California, from minus tide to 146 meters (80 fathoms).

Occurrence in San Diego Fm. — C.A.S. 2028.

Original description. — T. rotundato-triangularis,
equilateralis, equivalvis; valvis convexis, sub-tumidus: valva
superior rosea, lineis exilibus concentricis exasperata, et
costis ad 24 angulatis, alternis majoribus et spinis
erectis fornicatis insculpta: valva inferior pallidior colore
saturatiori zonata, costis sub-equalibus spiniferis armata;
natibus acutis, prominentibus; auribus obliquis valdé
inequalibus radiatim squamoso-striatis; intus porcellana;
marginibus crenulatis, rosaceis. Long. 4 1/2; alt. 1 1/4;
lat. 4 3/4 poll. (Gould.)

Remarks.— This subspecies is found only occasionally
in Pliocene strata at San Diego. This paucity was noticed
by Arnold and it is true of the collections which we have
seen from that area.

One excellent right valve collected by F. M.
Anderson at Loc. 2028 (CAS), Pacific Beach, along with
typical C. hastata, is 53.6 mm long, and 58 mm high.
This bears out Arnold’s observation that fossil forms of
this subspecies are generally smaller than Recent speci-
mens. A huge Recent specimen taken by Walter Eyerdam
in the Straits of Juan de Fuca, Puget Sound, Washington,
was reported to be 93 mm high and 73 mm wide (see Min.
Conch. Club South. Calif., No. 190, p. 18, 1959).

Chlamys hastata hericius (328) differs from typical
C. hastata in the generally larger size, less spinose ribs and

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

in that the ribs of the right valve are composed of a
fascicule consisting of three nearly equal, spiny riblets,
the middle one slightly more prominent, the whole more
convex in outline than the corresponding fascicule on C,
hastata. There is usually a riblet in the middle of each
interspace and between this and the major fascicule there
are usually two smaller threads and occasionally also a
finer pair of intercalaries. The ribs on the left valve also
consist of a fascicule of riblets which is more convex than
that of C. hastata. The surface in the interspaces between
the ribs of C. h. hericius is usually sculptured with very
fine oblique grooves or scratches similar to those on C.
hastata. Grau pointed out that the shell of C. hastata
often is oblique, whereas that of C. h. hericius seldom is.

Chlamys hastata hericius is a generally more northern
form, at the present time occurring abundantly in Puget
Sound often embedded in sponges. It has been recorded
as occurring from Port Althorp, Alaska, south to Newport
Bay, California, but we have not seen specimens from
southern California.

The form originally described as Pecten islandicus
pugetensis I. S. Oldroyd is similar to C. h. hericius but it
is generally smaller, the interspaces and sometimes the
entire valve bears fine honeycomb-like sculpture.

Masuda _ suggested that Chlamys miyatokoensis
Nomura and Hatai (329), which occurs in beds of early
Miocene age in Japan, may be an ancestral form of C.
hastata hericius. The riblets forming the major ribs of the
Japanese form are said to be divided into three subequal
parts by radial grooves and there are but two or three
riblets in the interspaces. Judging from the illustrations
given by Masuda, the radial fasciculi appear to be less
elevated into raised ribs lending an appearance of nearly
equal, spiny, radial riblets over all the right valve. The
anterior ears also are smaller than those on the west
American form. The medial sulcation giving rise to the
paired character of the ribs mentioned by Masuda also is
noticeable on some west American specimens (see our
plate 33, figure 2). Some of the illustrations given by
Masuda bear a decided resemblance to some forms of C. h.
hericius (see especially his plate 35, figure 9a) and his
suggestion that C. miyatokoensis may be an ancestral
form of C. h. hericius is plausible. The two, however, are
apparently distinct forms.

Masuda (330) also mentioned similarities and dif-
ferences between Chlamys hastata hericius and the Japa-
nese species C. kaneharai Yokoyama (331). The similarities
are very much less pronounced than are those with C.
miyatokoensis.

Chlamys (Chlamys) hastata ellisi n. subsp.
Plate 31, Figures 2, 3; Plate 34, Figure 6

Description. — Shell characters similar to those of
Chlamys hastata but differing in the presence of fine
honeycomb-like tesselations covering the interspaces and
sides of the ribs, but obscured on the tops of the ribs
where covered by strong imbricating spinose sculpture.
Length, 66 mm; height, 68.5 mm.

Type specimen. — Holotype, a right valve, Inverte-
brate Paleontology Collection, Los Angeles County
Museum.

Type locality. — Loc. 305 (LAM), 2400 feet east
and 1350 feet south of the northwest corner of Sec. 8,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

T. 19 S., R. 2 W., San Bernardino Base and Meridian
(see U. S. G. S. topog. map, San Ysidro quad., ed. 1943).

Range. — Known with certainty only from strata of
middle Pliocene age at the type locality.

Remarks. — In addition to the holotype a right
valve, 31 mm high, and two small left valves, the larger
one 20.8 mm high are referable to this new subspecies.
The entire surface of left valves is covered with minute
tesselations. This sculpture, composed of a layer of
minute scaly imbrications, is usually preserved in the
interspaces but sometimes covers the ribs as well. Often
the scaly honeycomb-like material is mostly gone and the
interspaces retain only a pattern of minute reticulation.
This type of sculpture (““Gittersculptur” of Philippi (332)
is present on C. islandica and allied forms. It also occurs
on many species in other groups of scallops, including
Manupecten, Patinopecten and Swiftopecten. It may be a
primitive character. This minute sculpture may easily
disappear with erosion and it is quite possible that some
fossil specimens lacking perfect preservation in the present
as well as in other collections, and referred to Chlamys
hastata or C. h. hericius, may represent C. h. ellisi n.
subsp. The only reliable basis for separating the present
new subspecies form C. hastata rests entirely on the
presence and recognition of the surficial tesselated sculp-
ture.

The minute sculpture of the present subspecies is
similar to that of the form described as Pecten islandicus
pugetensis (333). As mentioned by Gregg (334), the
presence of minute tesselation was not mentioned in the
original description by Oldroyd. The ribs of C. hastata
Pugetensis are more rounded than those of C. hastata,
those on each valve are nearly equal in size, and the fasci-
culi are minutely spinose. The interior of Recent shells is
often ornamented, especially around the ventral margin,
with dark red or red-orange color.

Chlamys hastata pugetensis is generally reported to
be smaller than C. hastata, C. h. ellisi n. subsp., and C. h.
hericius. Henderson (335), however, reported a specimen
77 mm high and long from deposits of Pleistocene age on
Big Hope Island in Puget Sound.

We have examined six specimens from the type lot
of C. h. pugetensis, the largest of which is 43 mm high.
The minute tesselated sculpture on some of these occurs
over nearly the entire valve but disappears near the ventral
margin. Four other Recent specimens from Puget Sound,
in the collections of the California Academy of Sciences,
likewise bear this characteristic minute sculpture. We also
have seen specimens from Duxbury Reef, Marin Co., and
from Monterey Bay, California, which retain traces of this
tesselated sculpture. One Recent specimen from Braca
Point, Washington, 51 mm high, possesses typical sculp-
ture of C. h. pugetensis until it is 26 mm high and then
follows sculpture of minute oblique groovings such as that
on C. h. hericius, which it resembles in general features.

Chlamys hastata pugetensis is reported living from
Sitkalidak Island, off eastern Kodiak Island, Alaska, to
Newport Bay, Califronia, from low tide to 91 meters (50
fathoms). It has been reported as a fossil by Gregg
(1938) from strata of “presumably Pliocene” age, Dead-
man Island, San Pedro, California, and questionably by
Grant and Gale (1931, p. 168) from strata of middle
Pliocene age southeast of Pico Canyon, Los Angeles Co.,
California.

191

It appears that since Pliocene time the members of
the Chlamys hastata group bearing honeycomb-like
tesselations have been reduced to one subspecies, which is
smaller, less numerous, and in general has become restricted
to cooler waters.

Chlamys (Chlamys) jordani Arnold
Plate 30, Figure 10; Plate 32,
Figure 3 (cf.), 5, 6, 10, 12,13

Pecten islandicus Muller, Dall, Proc. U. S. Nat. Mus., Vol.
1, pp. 11, 29, 1878. Later Tertiary of San Diego.
P. 29, on seacoast about 10 miles north of San Diego
“(stratum c).” — Cooper, Calif. State Min. Bur.,
Seventh Ann. Rept. Calif. State Mineral., p. 257, 1888.
“Pl. — San Diego.”

Not Pecten islandicus Muller, 1778.

Pecten (Chlamys) jordani Arnold, Mem. Calif. Acad. Sci.,
Vol. 3, p. 111, pl. 12, fig. 6, 7, June 27, 1903. —
Arnold, U. S. G. S., Prof. Paper 47, p. 114, pl. 44,
figs. 1, la, 1b (“Pliocene, Deadman Island, near San
Pedro, Los Angeles County, Cal.”), 1906. Also
“Pacific Beach, San Diego (Arnold), “Pliocene.” —
Arnold, U. S. G. S., Bull. 321, p. 32, pl. 14, figs. 5a,
5b, 1907. “Packards Hill’. Also “Pliocene, Deadman
Island, near San Pedro, Cal.; also found in the Fernando
formation at Santa Barbara and elsewhere.” ‘‘Pliocene.”
— B. L. Clark, Stratigraphy and Faunal Horizons of the
Coast Ranges of California (Publ. privately), p. 28
(as ““Pecten jordani Hertlein’’), pl. 47, figs. 3, 4, (as
“Pecten (Chlamys) jordani Hertlein”’), 1929. (Copies of
Arnold’s illustrations, 1906). ““Upper Pico formation of
Ventura County,” Pliocene.

Pecten jordani Arnold, McLaughlin and Waring, Calif.
State Min. Bur., Map folio accompanying Bull. 69,
inside of back cover, species 49, pl. 1, fig. 49, 1914.
“lower San Pedro formation at Timm’s Point, San
Pedro, California,” Pleistocene. — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1,
p. 55 (in part), 1924. ‘Pliocene of Santa Barbara, San
Pedro, and San Diego.” [Based upon Arnold’s records.
Not the record “Puget Sound,” Recent. |

Type specimen. — No. 162, 522, United States Na-
tional Museum.

Type locality. — “from the Pliocene of Deadman
Island,’ San Pedro, California.

Range. — Middle to late Pliocene or early Pleistocene.

Occurrence in San Diego Fm. — C.A.S. 105, 1132,
1183, 12149, 28893. L.A.M. 107, 305.

Original description. — Shell of medium size, shape
of P. hericeus, inequivalve, rather thin; right valve with
twenty-five to thirty angular, smooth-topped, imbricated
ribs, which become dichotomous after reaching a length of
about 30 mm; interspaces deeply channeled and narrower
than ribs; anterior ear imperfectly radially ribbed with six
ridges, and showing elevated, concentric, incremental
lines; posterior ear nearly obsolete, showing four ribs;
byssal notch not deep; left valve shows twenty-five to
thirty narrow, convex ribs, showing imbrications only
slightly; interspaces as large as ribs; after a diameter of
about 30 mm has been reached by the shell, small riblets
appear in the widening interspaces; anterior ear shows five
narrow, imbricated ridges, with wide interspaces; both
valves show a tendency to contract suddenly at the basal

192

margin upon nearing completion of growth; surface of
both valves covered with a minute, lattice-like sculpture,
which is generally worn off on exposed portions of the
shell. (Arnold.)

Dimensions. — Long. 42 mm; alt. 45 mm; diam. 15
mm; hinge 18 mm. (Arnold.)

Remarks. — Several earlier records of the occurrence
of this species in Pliocene beds at San Diego appear to be
based upon those of Dall, Cooper, and Arnold. Dall in
1878 cited Pecten islandicus from beds of Pliocene age at
Pacific Beach and apparently this formed the basis of
Cooper’s record (1888) of that species in the Pliocene at
San Diego. Arnold, 1906, indicated that Cooper’s record
was referable to Chlamys jordani Arnold.

Typical specimens of Chlamys jordani are quite rare.
The type specimen from beds of late Pliocene or early
Pleistocene age at San Pedro, California, was described as
45 mm high (336), 42 mm long; the umbonal angle
approximately 95°. The valves are sculptured with 25-30
ribs which become dichotomous after reaching a length of
about 30 mm. The ribs on the left valve are rather coarse
and a short midrib appears in the interspaces after the
valve has reached an altitude of about 30 mm. Both
valves tend to contract toward the base.

Typical specimens of this species are higher than
long and the general appearance is of a more slender shell
than that of Chlamys rubida. As mentioned by Arnold,
the right valve of C. jordani is similar to that of C. rubida
but the ribs on the left valve are quite different. These
reach to a height of about 20 to 30 mm, consist of simple,
nonfasciculated, moderately coarse ribs covered with fine
lattice-like sculpture but with only slight concentric
imbrication.

One right and one left valve, the larger one 27.3
mm high, from Pacific Beach are smaller than the type
of C. jordani and the ribs become dichotomous following
a constriction of the shell when 20 mm high. One right
and two small left valves, the largest one 17.5 mm high,
from India and Upas streets in San Diego, develop a con-
striction when 16 mm high. The ribs and interspaces of
all these valves are covered with very fine honeycomb-
like reticulate sculpture.

One right and two left valves from Loc. 107 (LAM)
are typical of C. jordani except for their larger size. The
right valve is 47 mm high and has two constrictions in
shell growth, one at 30 mm, and one at 42 mm. One left
valve 34 mm high has a constriction at 20 mm, the other
is 42 mm high (incomplete) and is gentiy contracted at a
height of 29 mm. The ribbing on these left valves is
dichotomous after the first constriction and, following
this, the splitting of the ribs and the development of strong
riblets in the interspaces result in more numerous finer
ribs. Another feature on these left valves is a decided
depression on the anterior ear where it joins the disk.

The only recent record of this species in beds of
Pliocene age which we have noticed is that of Kundert
(337) who cited it, provisionally, from the Los Angeles
region. The specimens were not illustrated.

The specimen from beds at Timm’s Point, San
Pedro, California, which was illustrated by McLaughlin
and Waring, is referable to Chlamys jordani. The specimen
from the same locality illustrated by Woodring (338) dif-
fers in several important details from the type of
Chlamys jordani. Woodring’s specimen, a right valve, is

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

almost as long as high and the umbonal angle is about
105° rather than 95°. The left valve was not illustrated.

Recent specimens identified by I. S. Oldroyd (339)
with Chlamys jordani are not typical of that species and
appear to be referable to the form described as Pecten
(Chlamys) hindsii kincaidi 1. S. Oldroyd (340). The same
is true of the specimen illustrated by Grau (341) which he
cited as Chlamys rubida jordani in the synonymy of which
he placed Pecten hindsii kincaidi 1. S. Oldroyd.

The smaller apical angle and consequently less
elongate, less discoidal shape as well as the constriction
followed by splitting of the ribs are characteristic features
of C. jordani as shown on Arnold’s illustrations of the
type specimen. These shell characters, in our opinion,
differ sufficiently from those of the form described as
kincaidi to justify separation of the two.

Chlamys jordani has been cited as occurring in beds
of Pleistocene age at various localities in southern Cali-
fornia from San Pedro to Santa Barbara and as far north
as British Columbia (342). Most of these records are not
accompanied by illustrations, consequently no opinion is
here advanced concerning the probable identification of
the species but it is almost certain that most of them are
not typical C. jordani.

Chlamys durhami Adegoke (343), described from the
Santa Margarita Formation of late Miocene age in the
Coalinga region, based upon a specimen 14.9 mm long
and 17.9 mm high, sculptured with 20 to 22 dichotomous
ribs, was compared by its author with C. jordani.

Several species occurring in beds of late Tertiary age
in the northwest Pacific and Japan are members of the
Chlamys rubida group, to which C. jordani belongs.
Masuda (344) pointed out the differences separating
Chlamys jordani from Chlamys akitana Yokoyama and
C. nisataiensis Otuka, which occur in the late Tertiary of
Japan.

Chlamys (Chlamys) opuntia Dall
Plate 30, Figure 5, 6

Pecten (Chlamys) opuntia Dall, Trans. Wagner Free
Institute Sci., Vol. 3, Pt. 4, p. 707, pl. 29, fig. 6,
April, 1898. — Arnold, Mem. Calif. Acad. Sci., Vol. 3,
p. 113, 1903. ‘‘Found in the Pliocene at Pacific Beach,
near San Diego.” Also Pliocene at Packard’s Hill,
Santa Barbara, California. — Schuchert, Dall, et, al.,
U.S. Nat. Mus., Bull. 53, Pt. 1, p. 490, 1905. ‘Pliocene.
San Diego County, California.”” — Arnold, U. S. G.S.,
Prof. Paper 47, p. 118, pl. 41, fig. 2, 1906. ‘Pliocene.
Pacific Beach, San Diego (Hemphill; Hamlin; Arnold.).”
— Arnold, in Eldridge and Arnold, U. S. G. S., Bull.
309, pp. 152, 244, pl. 36, fig. 8, 1907. ‘Pliocene,
Pacific Beach, San Diego County.”’ Also Santa Barbara;
Third Street Tunnel, Los Angeles. — Arnold, U.S. G. S.
Bull. 321, p. 32, pl. 14, figs. 3, 4, 1907. ‘Fernando
formation, Arroyo Burro, Santa Barbara,” Pliocene. —
Waterfall, Univ. Calif. Publ. Bull. Dept. Geol. Sci.,
Vol. 18, No. 3, opp. p. 78, 1929. “San Diego
Pliocene.’ — Keen and Bentson, Geol. Soc. Amer., Spec.
Papers No. 56, p. 91, 1944. Earlier records cited.

Pecten opuntia Dall, J. P. Smith, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 9, No. 4, pp. 150, 151, 1919. “San Diego.”
Also Fernando and Santa Barbara, Pliocene. — Carson,
Pan-Amer. Geol., Vol. 43, No. 4, pp. 268, 269, 270,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

1925. “San Diego fauna.” Also Ventura Formation
and Santa Barbara Formation, Pliocene.

Pecten (Pecten) opuntia Dall, Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 165, pl. 11, fig. 3
(Calabasas quad., Ventura or Los Angeles Co.), 1931.
“Type locality: Middle Pliocene of Pacific Beach,
San Diego.” Also other records.

Chlamys opuntia Dall, Woodring, Stewart, and Richards,
U.S. G. S., Prof. Paper 195, table opp. p. 112, 1940
(1941). “Strata at Pacific Beach.” San Diego. Upper
Pliocene. — Woodring, Bramlette, and Kew, U.S. G.S.,
Prof. Paper 207, p. 80,1946. “Based on material from
the upper Pliocene part of San Diego formation at
Pacific Beach... .”” Also Lomita marl.

Type specimen. — No. 107752, United States
National Museum.

Type locality. — “Pliocene of San Diego, California;
Hemphill and Hamlin.” Pacific Beach according to Arnold,
1906.

Range.
California and northern Lower California.
tocene in southern California (Woodring).

Occurrence in San Diego Fm. — C.A.S. 957, 1177,
11838, 1186. L.A.M. 107. S.D. 2931. Corner of Union
and State streets, San Diego. S.U. Pacific Beach.

Original description: Allied to P. hericeus var.
navarchus Dall, from which it differs by its smaller and
not fasciculated radial ribs, more elongated anterior ear,
more densely radially costate posterior ear, small size when
adult, and by a tendency to be suddenly contracted at the
basal margin on the completion of growth, somewhat as in
P. pesfelis. Alt. 35 mm, lat. 32.5 mm. (Dall.)

A supplementary description by Arnold follows:
Shell averaging about 35 millimeters in altitude, slightly
shorter than high, subequivalve, equilateral (except for
ears), both valves nearly flat until altitude of about 20 to
25 millimeters is reached, when they grow more convex;
contracted at basal margin when adult; sides only slightly
concave above. Right valve with 40 to 60 subequal, nar-
row, imbricated, more or less dichotomous ribs, which
are separated by channeled interspaces about equal in
width to the ribs; hinge line about two-fifths as long as
disk; anterior ear much produced, sculptured by about six
prominent, sharply imbricated radials, and imbricating in-
cremental lines; byssal notch quite prominent; posterior
ear nearly obsolete, radially and concentrically sculptured;

_ whole surface of disk and ears sometimes microscopically
checkered or tessellated. Left valve similar to right.

Dimensions. — Alt. 43 mm; long. 40 mm; hinge
line 16 mm; diameter 12 mm; umbonal angle 78”.
(Arnold, 1906.)

Remarks. — Several specimens, mostly single valves,
typical of this species, are represented in collections from
the San Diego Formation which we studied. A left valve
from Loc. 107 (LAM), is 38.4 mm long and 43.6 mm

| high. Some specimens are more rounded than others. A
left valve illustrated by Grant and Gale is 67 mm long
and 69 mm high. The fine, uniform, non-fasciculated
radial ribs are quite different from any other west
American Pliocene species.

Some authors have considered this species to be a
| member of the Chlamys islandica group. It somewhat
| resembles some fine-ribbed variants of that group but the
San Diego fossil is easily separable by its finer, even

— Middle and late Pliocene in southern
(Early Plies-

193

ribbing, slightly smaller umbonal angle, generally smaller
size and tendency to constriction toward the ventral
margin of adult forms. These features serve to separate it
from forms of C. rubida and its close relatives.

The ribbing and the umbonal angle of C. opuntia are
similar to those features on C. hertleini Loel and Corey
(345), which was described from beds of early Miocene
age. One decided difference in the two species is in the
outline of the posterior ears. The posterior ears on C.
opuntia slope obliquely downward from the hinge line
whereas those on C. hertleini are squarely truncated.

Chlamys tamurae Masuda and Sawada (346), com-
pared by its authors with C. opuntia, differs in that the
surface of the left valve (and to a less degree the right
valve) is folded forming low, broad corrugations. Further-
more, the illustration (see their fig. 12a) shows that the
major ribs are divided toward the ventral margin of the
right valve, a feature only occasionally present on C.
opuntia.

In addition to the San Diego Formation in which
the type specimen was found, Chlamys opuntia also has
been recorded from beds of late Pliocene age north of
Simi Valley, in upper Pico beds in Ventura Co., in
Temescal Canyon near Santa Monica, in beds encountered
in the Third Street Tunnel and elsewhere in Los Angeles,
and in the Tijuana-Rosarito Beach area in northwestern
Lower California. It also has been recorded from strata at
Santa Barbara and in the Lomita Formation near San
Pedro. These latter beds have been considered to be of
late Pliocene age by some writers and early Pleistocene age
by others. Grant (347) considered the Lomita Formation
to be of late Pliocene age and he suggested that the
sediment was deposited perhaps at depths of 30 to 90
meters (100 to 300 feet) and that the temperature was
about 15° to 17° C. (60° to 62° F.)

Chlamys (Chlamys) rubida Hinds
Plate 35, Figures 6, 8

Pecten rubidus Hinds, Zool. Voy. Sulphur, Moll., Pt. 3,
p. 61, pl. 17, fig. 5, 1844 (January, 1845, on cover).

Not Pecten rubidus Martyn, Univ. Conch., 1784. [Nomen-
clatorially unavailable. See Opinion 456 Internatl.
Comm. Zool. Nomencl., 1957. ]

Pecten hindsii Carpenter, Rept. Brit. Assoc. Adv. Sci. for
1863, p. 606, August, 1864. Page 645, as Pecten
hastatus ? var. Hindsii. Reprint in Smithsonian Misc.
Coll., No. 252, pp. 92, 131, 1872. New Name for
Pecten rubidus Hinds, not Pecten rubidus Martyn,
1784. Cited as occurring at Puget Sound; Vancouver
Island; Straits of San Juan de Fuca, and adjoining
shores. — I. S. Oldroyd, Stanford Univ. Pub. Univ.
Ser. Geol. Sci., Vol. 1, p. 53, pl. 7, figs. 3, 4, 1924.
(Copy of figures by Arnold, 1906). ‘Bering Sea to
San Diego, California.”

Pecten (2var.) Hindsii Carpenter, Proc. Acad. Nat. Sci.
Philadelphia, Vol. 17, p. 58, April, 1865. “Hab. — In
sinu Pugetiano juniorem legit U. S. E. E., adultum
Kennerley: in insula Vancouver legit Lord.”

Pecten hericeus var. navarchus Dall, Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 4, p. 708, April, 1898. (New
name for Pecten rubidus Hinds, 1844, not Pecten
rubidus Martyn, 1784). “San Diego, California, at Paci-
fic Beach, Hamlin,” “Pleistocene” [ Pliocene, according

194

to Arnold].

Pecten hastatus Sowerby var. navarchus Dall, Arnold,
U. S. G. S., Prof. Paper 47, p. 112, pl. 43, figs. 1, 1a,
1b (Recent, Puget Sound), 1906. “Pliocene. . .
Pacific Beach, San Diego. (Hamlin).” Also earlier
records.

Pecten (Chlamys) hastatus Sowerby var. hindsii Carpenter,
Arnold, U. S. G. S., Prof. Paper 47, p. 111, pl. 32, figs.
2, 2a (Recent, southeast Alaska), 1906. Pliocene to
Recent.

Pecten (Chlamys) hindsii Carpenter, I. S. Oldroyd, Publ.
Puget Sound Biol. Sta. (Univ. Washington), Vol. 4,
p. 17, pl. 23, figs. 3, 4, 1924. (Copies of figures by
Arnold, 1906). “Bering Sea to Cape San Lucas, Lower
California” [Not the record “Cape San Lucas, Lower
California.” |

Pecten (Chlamys) hindsii navarchus Dall, I. S. Oldroyd,
Puget Sound Biol. Sta. (Univ. Washington), Vol. 4,
p. 17, pl. 26, figs. 2, 3, 1924. (Copies of figures by
Arnold, 1906). ‘‘Bering Sea to San Diego, Calif.”

Pecten hindsii navarchus Dall, I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 54, pl. 4,
figs. 2, 3, 1924. (Copies of figures by Arnold, 1906).
“Bering Sea to San Diego, California.” Also Pleisto-
cene.

Pecten (Pecten) islandicus Miller variety hindsii Carpenter,
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1,
p. 163, 1931. “Middle Pliocene; Pacific Beach, San
Diego (Hamlin in Arnold).”

Pecten (Chlamys) rubidus Hinds, K. V. W. Palmer, Geol.
Soc. Amer., Mem. 76, p. 69, pl. 3, figs. 4-6, 1958.
[Carpenter’s species discussed. ] i

Chlamys rubida Hinds, Grau, Allan Hancock Pac. Exped.,
Vol. 23, p. 76, pl. 24, 1959. “Bering Sea to Monterey,
California. Also Pacific coast of Japan, as far south as
42° N.” “Just below low tide to 100 fathoms.” Also
Pliocene and Pleistocene. ;

Chlamys (Chlamys) rubida Hinds, MacNeil, U. S. G. S.,
Prof. Paper 553, p. 21, pl. 20, figs. 7, 9; pl. 22, figs. 7,
8.1967. Earlier records cited.

Type specimen. — Location unknown (Palmer,
1958). Originally in British Museum (Natural History).
Type locality. — ‘“Inhab. Alashka, North-west

America. At a depth of thirty-three fathoms.”

Range. — Middle Pliocene to Recent. Recent from
Bering Sea to Monterey (Grau), to Santa Rosa Island
(Yates (348), California. Recent from just below tide to
183 meters (100 fathoms).

Occurrence in San Diego Fm. — C.A.S. 105, 957,
1132, 28893. L.A.M. 107. S.D. 54.

Original description. — Testa subtrigono-orbiculari,
inaequaliter duplo-convexa, inaequiauriculata subtenui;
valva sinistra convexa, costis parvis numerosissimis, serratis,
in fasciculos duarum triumve alternate aggregatis, rufis,
interstitiis pallescentibus; valva dextra subconvexa, albida,
costis majusculis, aggregatis; auriculis sulcatis, postica
parva, obliqua; intus alba.(Hinds.)

Remarks. — The right valve of C. rubida is sculptured
with about 26 radial ribs which are wider than the inter-
spaces, flattish-topped, smooth, and usually dichotomous.
The interspaces are narrow, channeled, and sculptured with
fine reticulate honeycomb-like tesselations. The left valve is
sculptured with narrow, fasciculated ribs which are
crossed by fine concentric imbrications, the interspaces

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

are sculptured similar to those on the right valve.
The ribs on the right valve increase by bifurcation, those
on the left, at later stages of growth, by intercalation.
The sculpture of this species is quite variable.

Recent specimens of C. rubida are often about
60 mm high but we have seen fossil specimens 70 mm high.

One large right and one left valve, and several smaller
ones, of C. rubida are present in the collections from the
San Diego Formation. The largest is a left valve, 59.9 mm
long and 64.3 mm high, Cat. No. 4736 (SD), from India
Street near Spruce Street, San Diego.

The radial sculpture on some valves in the present
collection from Loc. 107 (LAM) is similar to that of the
species of late Pliocene age described by Waterfall as
Pecten (Chlamys) islandicus picoensis (349), and Pecten
(Chlamys) venturaensis (350). Grant and Gale believed
that the variation in sculpture in a series of C. “‘hindsii”’
is such as to embrace the forms named by Waterfall.
MacNeil (1967, p. 28), however, considers C. (C.)
picoensis to be a valid species, with two subspecies which
were originally described in Japan.

Typical specimens of C. rubida differ from C.
islandica in the generally smaller size, often less numerous
primary ribs, and especially in the smaller posterior ears.

The shell of C. rubida differs from that of C.
jordani in the fasciculate rather than simple ribs on the
left valve, usually the lack of honeycomb-like tesselation
on the tops of the ribs, and usually greater size.

Chlamys rubida usually has been cited in west
American literature under the name of Pecten or Chlamys
hindsii. Carpenter proposed a new name for the species
described by Hinds and stated (1864, p. 606), “ “Pecten
rubidus, Hds.’ Vane. Is., Lyall. [Hind’s type in Br. Mus.
appears the ordinary form, of which P. hastatus =hericeus
is the highly sculptured var. This shell, which is more
allied to Islandicus, may stand as P. Hindsii.] (351) In
the same publication (p. 645) he stated, ““Pecten (?var.)
Hindsii. Broader; ribs close, small, smooth, bifurcating.
Passes from hastatus toward Islandicus.” The following
year Carpenter (1865, p. 58) gave the dimensions as “Long.
1.6, lat. 1.7, alt. .57”, presumably referring to “Poll”
(Pollex) as used on page 54. This indicates a height (beak
to base) of approximately 40.51 mm.

The original illustration of Pecten rubidus is that of
the exterior of a left valve, the ribs of which are fascicu-
lated and crossed by fine concentric imbrications. The
color is pink with concentric zones of lighter color. This
illustration bears a resemblance to Arnold’s illustration
(1906, pl. 43, fig. la) of “Pecten hastatus Sowerby var.
navarchus Dall.” Carpenter (1864, p. 645) in a com-
parison with P. hastatus mentioned “In var. rubidus, Hds.
(non Mart.), the ribs are equal, not serrated.”

Palmer (1958, p. 70) called attention to the fact that
the name Pecten hindsii Carpenter was based upon a
specimen collected by Dr. Lyall at Vancouver and that
Carpenter thought that this specimen was not identical with
Pecten rubidus Hinds. She illustrated three right valves in
the collection of the Redpath Museum which Carpenter
identified as ‘‘Pecten Hindsii Cpr. = rubidus, H. C. Sitka.”
Unfortunately, the lack of left valves in the Redpath
collection makes impossible comparison with the original
illustration of the left valve of P. rubidus shown by Hinds.

Through the courtesy of F. Stearns MacNeil we have
had the opportunity to examine the valves from the Red-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

path Museum. The major ribs on these right valves are
flattish and rather smooth on top and dichotomous toward
the ventral margin. A right valve (see our pl. 35, fig. 8)
from Loc. 107 (LAM) from the San Diego Formation is
quite similar to the specimen illustrated by Palmer on her
plate 3, figure 6. A similar development of ribbing is
present on the form described as Pecten (Chlamys)
hindsii kincaidi 1. S. Oldroyd (352) from Puget Sound.
The type of that species is a suborbicular shell which has
flattish smooth topped ribs on the right valve and round
topped ribs with only faint intercalaries on the left valve.

According to Palmer the type specimens of both P.
rubidus and P. hindsii cannot be found. Considerable
variation in sculpture is revealed in a series of specimens
of this species complex and the relationship of the two
is not definitely known at the present time. The speci-
mens identified by Carpenter as ‘Pecten hindsii,”
illustrated by Palmer, furnish some justification for
retaining this form as a subspecies of C. rubida and this
interpretation of Carpenter’s species was proposed by
MacNeil (U.S. G. S., Prof. Paper 553, p. 22, pl. 18, figs. 4,
6; pl. 19, figs. 1, 3, 4, 6; pl. 20, figs. 5, 6; pl. 21, fig. 4;
pl. 22, figs. 1, 2; pl. 24, figs. 1, 8,9, 1967). The two forms
apparently represent extreme variants in the fine and
coarse character of the ribs. The variation in sculpture of
the fossils from the San Diego Formation is such that
we assign to them the earliest name proposed for this
group, at least until the relationship of the variants of this
species complex is better known.

A right valve from the Gubik Formation, of
Quaternary age in northern Alaska, which MacNeil (353)
illustrated under the name of “Chlamys hindsii” was
later described as Chlamys (Chlamys) beringiana colvillensis
MacNeil (1967, p. 26, pl. 18, figs. 5, 7).

Pecten clemensae and Pecten newcombi of I. S.
Oldroyd (354), nomina nuda, may be referable to C.
rubida or to C. rubida hindsii or to the form described as
C. kincaidi.

In the Japanese region, specimens referred to
“Chlamys islandica hindsi’’ have been illustrated by Kira
(355), and by Oyama and Takemura (356). According to
Kuroda and Habe (357), this species occurs on the Pacific
Ocean side of Japan from 42° to 55° North Latitude. We
have not studied a series of specimens of the Japanese
form but illustrations of specimens referred to C. hindsii
from that region do not agree in detail with west American
forms identified under that name. The record of
Dautzenberg and Bavay (358) of C. “hindsii” in the Sulu
Archipelago in the East Indies is referable to some other

- species (see Grau, 1959, p. 77).

re

The larger shell and flattish radial ribs on the right
valve which are broader than their interspaces are features
separating C. rubida from C. imanishii Masuda and
Sawada (339) which was described from beds of Pliocene
age in Japan.

Chlamys ingeniosa tanakai Akiyama (360) bears a
resemblance to some forms of C. rubida as mentioned by
Akiyama but we have not had specimens for careful
comparison.

In addition to the occurrence of Chlamys rubida in
strata of Pliocene age at San Diego, it was reported from
Fourth and Broadway in Los Angeles by Willett (3861), from
the Ventura region by Waterfall (as Pecten (Chlamys)
islandicus picoensis and P. (C.) islandicus venturaensis),

195

and from the Ohlson Ranch Group in Sonoma Co. by
Peck (362). Nomland (363) reported it as Pecten
hastatus hindsii from the Pecten coalingaénsis zone of the
Etchegoin Formation. Stewart (364) later reported frag-
ments of “C. cf. C. islandicus (Muller)” from the Acila
zone in the San Joaquin Formation in Kettleman Hills,
but he did not record C. rubida from that area.

SUBGENUS ARGOPECTEN MONTEROSATO

Argopecten Monterosato, Jour. de Conchyl., Vol. 37
(Ser. 3, Vol. 29), No. 1, p. 20, 1889. Several species
cited including “Argopecten solidulus, Reeve (Pecten,
1853). — Pl. 33, fig. 155. (Hab. ?) = P. Philippii, (non
Michelotti, 1839, espece fossile) Récluz, 1854 = P.
commutatus, Monterosato, 1875. C’est aussi le P.
gibbus, Philippi (non Lamarck). — Espeéce Méditer-
ranéenne et des Canaries.” — Grau, Allan Hancock Pac.
Exped., Vol. 23, p. 93, 1959. [Not “Type-species:
Pecten commutatus Monterosato, 1875, p. 6.” Con-
cerning Grau’s citation of type species see Keen,
Veliger, Vol. 2, No. 4, p. 101, 1960.] — Waller, Jour.
Paleo., Vol. 43, Suppl. to No. 5 (Paleo. Soc., Mem. 3),
p. 32,1969. Type, Pecten solidulus Reeve.

Plagioctenium Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 4, p. 696, April, 1898. “Type P. ventricosus Sby.”
— Tucker-Rowland, Mem. Mus. Roy. d’Hist. Nat.
Belgique, Deuxiéme Sér., Fasc. 13, p. 32, 1938. “Type.
—‘Pecten’ ventricosus Sowerby =C. gibbus circularis
Sowerby, by original designation, Dall, 1898.”

Type species (by subsequent designation, Mon-
terosato, Journ. de Conchyl., Vol. 47, No. 3, p. 193,
1899). — “Type: P. solidulus, Reeve = P. Philippii,
Recluz (non Michelotti) = P. commutatus, Monts.”
Illustrated by Reeve, Conch. Icon., Vol. 8, Pecten,
sp. 155, pl. 33, fig. 155, August, 1853. ‘‘Hab.-?)” —
Kobelt, Syst. Conchyl. -Cab. von Martini und Chemnitz,
Bd. 7, Abt. 2, Spondylus und Pecten p. 219, Taf. 58,
fig. 8, 1888. [Copy of Reeve’s illustration.] — Waller,
1969, p. 33, pl. 1, figs. 11, 12, 14, 15 (illustrations of
holotype).

Range. — Early Miocene to Recent, worldwide in
shallow, warm temperate and tropical marine waters.

Description. — Suborbicular, thick, sometimes large,
equiconvex (right valve usually deeper) and with a
tendency to oblique growth in adult; auricles large and
nearly equal in length; ribs numerous, usually undivided,
rounded or often squarish, crossed by concentric imbrica-
tions which are concave dorsally, or the ribs are frequently
smooth; upper valve of Recent shells often richly colored
with red or purple blotches.

Remarks. — Many American species of Argopecten
have appeared in the literature under Aequipecten and
Plagioctenium. This subgenus differs from Aequipecten in
that the valves are nearly equally convex, the ribs and
interspaces usually lack well developed radial lirae and
there is a tendency toward obliquity in adult shells.
Waller (365) published an extensive report dealing
especially with the east American members of Argopecten.

The type species of Argopecten, Pecten solidulus
Reeve, was based upon a juvenile shell. This species has
been confused with Pecten commutatus Montersato, a
name proposed for Pecten philippii Reécluz, 1853 (not
Pecten philippii Michelotti, 1839), a Mediterranean species.

196

More recently, Dr. F. K. North examined the type
specimen of P. solidulus and found it to be quite distinct
from P. commutatus. Dollfus (386) placed Reeve’s
species in the synonymy of ‘‘Pecten (Chlamys) flabellum”
Gmelin, a west African species. Waller (1969, p. 33)
believes that P. solidulus is probably referable to P.
circularis Sowerby.

The shape, ribbing and coloration shown by Reeve’s
illustration of P. solidulus are similar to juvenile forms of
Pecten gibbus as mentioned by Reeve.

It is unfortunate that the type species of Argo-
pecten is based upon a juvenile shell, and information
concerning the locality from which it came is lacking.
However, the type specimen is preserved in the British
Museum and its shell characters appear to be referable to
one of the members of the well known C. gibba-
circularis group. For that reason we have referred several
west American species to Argopecten in the synonymy of
which we include Plagioctenium which is better known for
this group but which was published later than Argopecten.

Argopecten includes, among others, the well known
late Cenozoic American C. circularis-gibba-irradians group.
It is well represented in the Caribbean region where F. and
H. Hodson recorded subspecies of C. circularis from the
Miocene and the Pliocene of Venezuela. Other species
occur in the late Cenozoic of the Atlantic and Gulf coasts
of eastern United States as well as in the Antilles and
northwest Africa. Probably some species in other regions
may be referable to this subgenus. Speciation in this
group progressed rapidly during the Pliocene period.

The earliest representative of Argopecten recorded
from western North America is Chlamys (Argopecten)
neahensis Arnold (367) from beds of middle Miocene age
in Washington. We have examined a cast of the type
specimen and we agree with Arnold’s conclusions con-
cerning its similarity to C. circularis. We find no reason
to place it doubtfully in the synonymy of a species of
Lyropecten as was done by Grant and Gale (1931, p. 184).
Other than inspection of this cast we have not seen
specimens of this species. Weaver (1943), however,
reported it from the general area from which the type came.
This is the only species reported up to the present time
from the Miocene of western North America which is
definitely referable to Argopecten but this subgenus was
represented by a number of species during Pliocene time
in southern California and Lower California and in more

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

southern regions. At the present time two species (C.
purpurata and C. circularis) and one subspecies (C.
circularis aequisulcata) live in tropical and subtropical
west American waters. Other species live in the western
Atlantic, west Africa, and elsewhere.

From the known occurrences of species, one may
infer that Argopecten had its origin in tropical or temperate
waters in early Miocene time.

Chlamys (Argopecten) abietis abbotti n. subsp.
Plate 34, Figure 5; Plate 36, Figures 1, 6

Type specimen. — Holotype in the type collection
of the San Diego Society of Natural History.

Type locality. — From cut in exposure at Frontier
Housing Project, Loma Portal, San Diego, California;
Patrick Hanratty collector, April, 1945.

Additional localities in San Diego Fm. — C.A.S.
L.A.M. 302A, P.87: No. 8325. S.D. 409.

Description. — Shell large, thick, both valves highly
convex, somewhat elongated posteriorly; hinge line long,
a little over two thirds the length of the valves. Right
valve with 21 radial ribs which are high, narrowly flat-
topped and steeply sloping until the valve is about
70 mm high, then becoming lower and broadly rounded;
the sides of the ribs and the interspaces are ornamented
with close-set fringing lamellae; anterior ear sculptured
with 4 or 5 fine radial riblets, a well developed byssal
notch present; posterior ear faintly radially striated and
with lines of growth which reveal a shallow sinuation.
Left valve with ribbing similar to that of the right except
that the ribs are narrower and more triangular, the
anterior ear with a shallower notch and with faint traces of
fine riblets. Inner margin of valves scalloped by the cor-
responding ribs and interspaces on the exterior. Dimen-
sions: length 129.0 mm, height 118.0 mm, convexity
(both valves together), 64.0 mm, length of hinge line
88.0 mm.

Remarks. — The shell characters of this new sub-
species appear to be intermediate between those of
Chlamys (Argopecten) abietis E. K. Jordan and Hertlein
(368) and those of C. (A.) circularis aequisulcata
Carpenter (369). This new subspecies differs from
C. (A.) abietis in the deeper notch under the right
anterior ear, in the more widely spaced ribs and by the
more flattened character of the ribs toward the ventral

Key to Species and Subspecies of Argopecten

A. Valves highly and nearly equally convex

a. Major ribs of right valve (22)
with small riblet at base on

Cachysides-5. 6 Gate ones ee . ericellus
aa. Major ribs of right valve (18
to 21) lacking riblet at base

b. Ribs on left valve rounded . circularis

bb. Ribs on left valve triangular . abbotti

B. Valves moderately convex, the
left decidedly more so

a. Ribs 18 to 22; shell of
moderate size

b. Ribs 18 to 21; ribs decidedly
widened toward ventral
reed Go oo oo 6

bb. Ribs 21 to 22; ribs not
decidedly widened toward
ventral margin

invalida

c. Ribs low, rounded, subobsolete
toward ventral margin .

ec. Ribs squarish, high, retaining
this character to ventral
margin

subdola

callida

aa. Ribs 24 to 27; shell large, coarse,

thick . hakei

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

margin of the left valve. It differs from C. (A.) cir-
cularis aequisulcata in the larger, thicker shell, longer
hinge line, more triangular shape of the ribs in the early
stages of growth but which become rounded and flattened
toward the ventral margin on the right valve, and also in
the more highly convex left valve with narrower inter-
spaces between the ribs.

The rotund appearance of large specimens of this
new subspecies lends a general resemblance to C. (A.)
hakei Hertlein but it may be separated from that species
by the fewer ribs (21 or 22 rather than 24 to 27) which
are triangular until the shell is about 70 mm high and then
become broader and flatter toward the ventral margin.

A large, thick, left valve in the collections of the Los
Angeles County Museum, collected by Charles Sternberg
at 32nd Avenue and Woolman Street, San Diego, is 105
mm long, 96 mm high, the convexity about 27 mm. It is
sculptured with 21 ribs. The interior is reddish-brown in
color especially the ventral half of the valve. The shell is
partially covered with hard, gray, fine grained sandstone.
Small oysters are attached to the exterior of the valve as
might occur if the empty shell lay upon the sea bottom for
a time before it was covered with sediment. The very
large size of this valve and the traces of coloration on the
interior are similar to those of C. (A.) c. aequisulcata
Carpenter but the size and thickness correspond more with
those of C. (A.) abietis abbotti and we refer it provi-
sionally to this subspecies.

Two specimens from Loc. 595 (UCLA), about two
miles north of Somis, Ventura Co., California, in a
Pecten reef apparently near the base of the Long Canyon
Member of the Las Posas Formation, of late Pliocene age,
are quite similar to the type specimen of C. (A.) abietis
abbotti but the ribs are slightly broader. The larger
specimen is 141.5 mm long, 132.6 mm high, the convexity
(both valves together), 61 mm. A smaller specimen col-
lected with the two large fossils from Ventura County, is
74 mm long, 69.6 mm high, the convexity (both valves
together), 34 mm. The ribs on this specimen, especially
on the left valve, are triangular with fringing lamellae,
corresponding in every way with typical C. (A.) abietis of
the same size from Lower California.

This subspecies is named for Clinton G. Abbott,
former Director of the Museum of the San Diego Society
of Natural History, whose encouragement to the authors
during the preparation of the early portion of this memoir
is greatly appreciated.

Chlamys (Argopecten) circularis Sowerby
Plate 32, Figures 4, 15, 16

Pecten tumidus Sowerby, Proc. Zool. Soc. London for
1835, p. 109, October 9, 1835. “Hab. ad Sanctam
Elenam et ad Salango, Columbiae occidentalis. Found
in sandy mud at from six to ten fathoms.”

Not Pecten tumidus Turton, 1822.

Not Pecten tumidus Hartmann in von Zieten, 1833.

Pecten circularis Sowerby, Proc. Zool. Soc. London for
1835, p. 110, issued October 9, 1835. ‘Hab. ad
Sinum Californiae. (Guaymas).” ‘Found in sandy
mud at a depth of seven fathoms.” — Sowerby, Thes.
Conch., Vol. 1, Pecten, p. 51, pl. 12, fig. 23, 1842.

Pecten ventricosus Sowerby, Thes. Conch., Vol. 1, p. 51
pl. 12, figs. 18, 19, 26, 1842. A new name for Pecten

197

tumidus Sowerby, 1935. Not Pecten tumidus Turton,
1822, nor Pecten tumidus Hartmann in Zieten, 1833.
— Reeve, Conch. Icon., Vol. 8, Pecten, species 31, pl. 7
figs, 31a, 31b, 1852. Not the locality “Philippine
Islands.”

Pecten (Plagioctenium) circularis Sowerby, Arnold, U. S.
G. S., Prof. Paper 47, p. 125, pl. 42, figs. 3-6; pl. 44,
figs. 6, 6a, 6b, 7, 1906. “Pliocene (?). Cholas Valley,
near San Diego (Stearns).” Also Pleistocene. Recent
from the Gulf of California to Santa Elena, Ecuador. —
E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci., Ser.
4, Vol. 15, No. 14, p. 439, 1926. “The San Diego
Pliocene at Pacific Beach, near San Diego, California.”

Aequipecten (Plagioctenium) circularis Sowerby, Keen,
Sea Shells of Tropical West America (Stanford Univ.
Press: Stanford, California), p. 72, fig. 132, 1958. Gulf
of California to Paita, Peru. — Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), p. 163, pl. 19, figs. 2, 2a, 2b, 1961. Recent,
Lower California to northern Peru.

Chlamys (Argopecten) circularis Sowerby, Grau, Allan
Hancock Pacific Exped., Vol. 23, p. 97, pl. 32, 1959.
Cedros Island, Lower California, Mexico, to Paita, Peru,
and the Galapagos Islands, at depths from 4 feet to 75
fathoms. Also, ?Pliocene and Pleistocene.

Type specimen. — No. 1950-11-14.18.19., British
Museum (Natural History).

Type locality. — “Hab. ad Sinum Californiae.
(Guaymas).” “Found in sandy mud at a depth of seven
fathoms”.

Range. — Middle Pliocene to Recent. Recent from
Cedros Island, Lower California, Mexico, to Bayovar,
Peru, and the Galapagos Islands, in 1 to 137 meters (1 to
75 fathoms). “Found on rock, gravel, sand, sandy
mud bottoms; associated with kelp, corallines or gorgon-
ians.” (Grau.)

Occurrence in the San Diego Fm. — C.A.S. 1132,
1137. L.A.M. 305, 305A, 320, 320A. S.D. 412. U.C.L.A.
306.

Original description. — Pect. testa suborbiculari,
tumida, subaequivalvi, aequilaterali, fusco alboque varia,
auriculis magnis, subaequalibus; costis radiantibus octo-
decim interstitiis latioribus, arcuatim striatis; valva altera
sulcis profundioribus: long. 1.5, lat. 0.8, alt. 1.4 poll.
(Sowerby.)

Remarks. — About 45 specimens, mostly single
valves, are here referred to Chlamys circularis. A right
valve from Loc. 320 (LAM), near the Mexican boundary, is
84 mm long, 83.5 mm high, the convexity (one valve)
about 28 mm. Another right valve from Loc. 1137 (CAS),
corner of Logan Avenue and 31st Street, San Diego, is
49.5 mm long. Many smaller, well preserved valves also
occur with these larger specimens. An interesting feature
of many of these fossils is that they retain traces of
coloration.

The larger valves are definitely referable to Chlamys
circularis. In the smaller valves, there is much variation
in the convexity, the width of the interspaces between the
ribs and in the height and degree of rounding or flattening
of the tops of the ribs. Many of the valves to a height of
about 35 mm are very convex, the ribs are high and flat-
topped and rather closely spaced. These closely resemble
Arnold’s illustration (1906, pl. 44, fig. 7) of the type of
Pecten compactus Dall which is now generally placed in

198

the synonymy of C. circularis. Other larger ones resemble
Arnold’s illustration of C. circularis (on his plate 42, fig.
3). Large specimens of C. circularis from the Gulf of
California are about 66 mm long.

Some of the small specimens resemble C. (A.)
circularis aequisulcata Carpenter (370), but the shells are
somewhat thicker, the ribs are wider and the coloration
appears to have been more pronounced than on the
subspecies. A comparison of these small fossils with a
series of specimens of Recent C. (A.) circularis from
tropical west American waters reveals similar convexity
and ribbing in the early stages of the Recent species.

Recent adult specimens of C. (A.) circularis aequi-
sulcata differ from typical C. (A.) circularis in the larger,
flatter, and thinner shell as well as in the narrower ribs
and less brightly colored shell.

Chlamys circularis is very similar to the Recent east
American species, C. gibba Linnaeus (371), but differs in
details, especially in the decided angulation delimiting the
posterior ear from the disk on the right valve. Davenport
(372) made a comparative study of a large number of
specimens of these two species from the east and west
coasts of North America and found some difference in the
convexity and in the less obliquity of the west coast form.
The two species are undoubtedly members of a closely
related group but we do not consider them to be identical.

Several species and subspecies allied to the C. gibba-
circularis group have been described from strata of late
Miocene and Pliocene age in southeastern United States.
These have been discussed by Tucker-Rowland, by Mans-
field, and by Waller. Weisbord (373) recently discussed
thirteen species and subspecies of this group. %

Some of the fossils from the San Diego formation
closely resemble some specimens of the form described as
Pecten (Plagioctenium) calli Hertlein (374) from beds of
Pliocene age at Bahia Tortolo (Turtle Bay), Lower Cali-
fornia. The record of this form from the San Diego
Pliocene, mentioned by E. K. Jordan and Hertlein, is
referred by us to juvenile C. circularis. Typical specimens
of the form C. c. calli possess very highly arched umbos,
squarish ribs on the right valve and fine, high ribs on the
left valve. There is also a tendency for the valves to
develop a length greater in proportion to the height.
Durham (375) mentioned this tendency in C. circularis
occurring in Pliocene beds in the Gulf of California region.
The valves of C. circularis calli are more elongated and the
ribs are more numerous and narrower than those of C.
circularis bramkampi Durham (376) described from the
Carrizo Creek region in Imperial County, which has about
19 ribs.

In general appearance and in degree of globosity,
some of the smaller specimens from San Diego resemble C.
eldridgei Arnold (377) which was described from beds of
late Pliocene age in San Joaquin Valley, California. The
fossils from San Diego have thinner shells, which lack
constrictions, the ribs are more numerous, often a little
more widely spaced and the crenellations along the ventral
margin of the interior are less consistently and deeply
grooved than those of C. eldridgei. The ribs on some of
the left valves of C. eldridgei are shallowly medially
grooved toward the ventral margin but this feature is
lacking on the valves from San Diego.

Some of the present specimens bear a resemblance
to Chlamys deserti Conrad (378) but differ from typical

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

specimens of Conrad’s species. The original description
of Chlamys deserti was based upon a left valve with 23
ribs. Arnold (379) illustrated specimens from Carrizo
Creek, the type locality of C. deserti, and mentioned
the correct number of ribs.

Grant and Gale (1931, p. 212) cited the number of
ribs on the deserti group “usually 18 or 19”’, and on typical
deserti 15 to 19. Woodring and Stewart (1941, p. 91)
stated that C. deserti,had fewer ribs than P. impostor
which originally was described as possessing 21 to 24. It
appears obvious that some of the specimens attributed to
C. deserti are not referable to it. Judging from the
original description given by Conrad, the left valve
illustrated by Arnold (1906, pl. 26, fig. 3), the illustra-
tions of Nomland (1917, pl. 6, figs. 1, 1a, 1b), those of
Hanna (1926, pl. 25, figs. 1, 2, 3), and of Durham (1950,
pl. 11, figs. 5, 6) correctly delineate typical specimens of
Conrad’s species.

The present fossils from San Diego are more elon-
gate than typical C. deserti, they have fewer ribs, the
submargins are wider and not sculptured with riblets and
the ears are more concave. They are referable to the
variable species,C. circularis.

Several members of the C. circularis group have been
described from strata of Miocene age. The species
described as Pecten (Plagioctenium) neahensis by Arnold
(1906, p. 87, pl. 15, fig. 2, 2a, 2b) from beds of
Miocene age at Neah Bay, Washington, has narrower ribs
and a longer hinge line than C. circularis. The type
specimen is definitely referable to Argopecten as men-
tioned in our discussion of that subgenus.

Three subspecies of C. circularis were described by
F. and H. Hodson, from beds of Miocene and Pliocene
age in the Caribbean region. These were described as
Pecten circularis cornellanus (380), Miocene; Pecten
circularis venezuelanus (381), Miocene and Pliocene; and
Pecten circularis caucanus (382) of Pliocene age. These
were said to generally differ from typical Chlamys
circularis in details of sculpture but that intergradation
exists with that species. Another member of this group
described as Pecten (Plagioctenium) demiurgus by Dall
(383) (to which species Grant and Gale referred some west
American records of C. circularis) from strata of late
Miocene age in Trinidad, has higher, narrower umbones
and the ribs are said to be wider and more closely spaced
than those of the Recent west American species.

Chlamys (Argopecten) callida Hertlein
Plate 32, Figures 9, 11

Pecten (Plagioctenium) callidus Hertlein, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 14, No. 1, p. 22, pl. 5, figs. 1,
3, 5, 6, July 21, 1925. — E. K. Jordan and Hertlein,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 437,
1926. ‘San Diego Pliocene of Pacific Beach near San
Diego, California.’’ Also Cedros Island and Turtle Bay,
Lower California, Pliocene.

Pecten (Aequipecten) purpuratus Lamarck variety callidus
Hertlein, Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 211, pl. 5, fig. 4 (Fernando Pass, Los
Angeles Co., 1931. “San Diego (Stanford collection).”
Pliocene.

Type specimen. — No. 53, Stanford University,

Department of Geology, Type Collection.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Type locality. — ‘‘Cedros Island, Lower California.”
“Salada, Pliocene.”

Range. — Middle Pliocene of southern California
and northern Lower California.

Occurrence in San Diego Fm. — C.A.S. 105, 1138,
1413, 1414, 12145. L.A.M. 122, 127, 305.

Original description. — Shell of medium size, the
valves moderately arched. Right valve ornamented by
about 21 or 22 rather high, flat-topped, radiating ribs
separated by narrower interspaces, tops of ribs smooth,
but sides and interspaces sculptured by fine, sharp
lamellae; anterior and posterior margins sculptured by con-
centric lines of growth only; ventral margin rounded; ears
unequal, the anterior with a large byssal notch and
ornamented by about five or six radiating riblets crossed
by concentric lines of growth; the posterior sculptured by
several radiating riblets. Left valve more convex than
right and somewhat one-sided in appearance, with sculp-
ture quite similar to that of right valve except that the
interspaces are slightly wider; anterior ear carrying a
small, rounded notch and ornamentation consisting of
small, radiating riblets and concentric lines of growth;
posterior ear sculptured much as the anterior. Altitude
55 mm; longitude 55 mm; diameter 19 mm; apical angle
of valves approximately 105°. (Hertlein.)

Remarks. — Several specimens of Chlamys callida
are present in collections from Pliocene beds at Pacific
Beach. One of the largest of these is 55.5 mm long;
53.5 mm high; convexity (both valves together) 19.6 mm;
length of hinge line 30.5 mm; umbonal angle 105°.

The shell of this species is characterized by the
gently convex right valve and sculpture consisting of 21
to 22 well developed flat-topped ribs which are separated
by narrower interspaces. The left valve is more convex than
the right, but is similarly sculptured except that the ribs
are narrower and separated by wider interspaces.

The outline and general sculpture of this species is
similar to that of Chlamys subdola, but it differs from that
species in the much higher flat-topped ribs which retain
this character to the ventral margin.

The greater size, greater number of flat-topped ribs
which retain this character to the margin, the lack of
interrupted concentric zones of growth and the greater
umbonal angle, are features which serve to separate C.
callida from C. invalida.

To the north of San Diego, Chlamys callida has been
reported by Grant and Gale as occurring in beds of
Pliocene age in the Los Angeles region. To the south it is
known to occur at Cedros Island and at Bahia Tortolo
(Turtle Bay) on the west coast of Lower California. It
has been recorded by Vokes (384) as occurring in the
Gloria Formation of middle Pliocene age and in the
Infierno Formation of late Pliocene age in the Santa
Rosalia district on the east coast of Lower California. The
specimen cited by Hanna and Hertlein under the name of
this species from San José Island in the Gulf of California is
not typical of C. callida.

Chlamys (Argopecten) ericellus Hertlein
Plate 32, Figure 7

Pecten (Plagioctenium) ericellus Hertlein, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 18, No. 5, p. 215, pl. 24, figs. 10, 11
(in No. 8), April 5, 1929. — Keen and Bentson, Geol.

199

Soc. Amer., Spec. Papers No. 56, p. 85, 1944. Original
record cited.

Type specimen. — No. 2998, California Academy of
Sciences, Department of Geology, Type Collection.

Type locality. — “Pacific Beach, San Diego, Cali-
fornia.”’ “San Diego Pliocene.”

Range. — Known only from the type locality.

Occurrence in the San Diego Formation. — Cali-
fornia Academy of Sciences: Loc. 1132, Pacific Beach
(Sternberg Loc. 34).

Original description. — Shell small, moderately con-
vex; hinge line straight. Right valve ornamented by about
22 subrounded, fairly low radiating ribs which are
separated by narrower interspaces; two tiny midribs are
present along the base of the sides of the major ribs; ribs
and interspaces crossed by concentric lines of growth;
anterior and posterior margins ornamented by concentric
lines of growth; ventral margin rounded; ears unequal, the
anterior with a well-defined byssal notch, and sculpture of
about five or six radiating riblets crossed by incremental
lines; the posterior ear sculptured by about four or five
radiating riblets crossed by lines of growth, no notch
present. Altitude 28 mm; longitude, 29.1 mm; diameter
of right valve approximately 7.5 mm; apical angle in right
valve approximately 94°. (Hertlein.)

Remarks. — The shell of this species is characterized
by its narrow, subrounded ribs, narrow interspaces, and by
the presence of two tiny riblets, one at the base of each
side of most of the major ribs. In some of the interspaces
toward the lateral margins only one riblet, or in some
cases, none is present.

This form appears to be a member of the Chlamys
circularis group. It differs from C. circularis in the smaller
posterior ear, more numerous, narrower ribs and inter-
spaces, and in the presence of the riblets in the interspaces
toward the ventral margin.

Grant and Gale (1931, p. 219) stated that this form
could be matched by juvenile specimens of Chlamys
circularis aequisulcata Carpenter. However, they cited it
with question in the synonymy of “‘Pecten (Aequipecten)
gibbus variety circularis Sowerby.” Comparison of the
type specimen of C. (A.) ericellus with a series of specimens
of C. circularis and its subspecies C. circularis aequisulcata
of comparable size, reveals differences sufficient in our
opinion to justify assignment of specific status to C. (A.)
ericellus.

Chlamys (Argopecten) hakei Hertlein
Plate 33, Figure 10

Pecten (Plagioctenium) hakei Hertlein, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 14, No. 1, p. 18, pl. 4, figs. 1, 3, July
21, 1925. — E. K. Jordan and Hertlein, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 440, pl. 31, figs.
1, 2 (“Cedros Island” and “Turtle Bay”, Lower Cali-
fornia; Pliocene), 1926.

Pecten (Aequipecten) purpuratus Lamarck variety hakei
Hertlein, Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 209, pl. 8, fig. 3, 1931. Type speci-
men illustrated. Earlier records cited. Cited from “San
Diego formation (Hertlein and Grant),’ also from
Pliocene of Lower California and Ventura Co., Cali-
fornia.

Type specimen. — A right valve, No. 40, Stanford

200

University, Department of Geology, Type Collection.

Type locality. — “Turtle Bay, Lower California,”
Salada, Pliocene.

Range. — Middle Pliocene of southern California
and northern Lower California.

Occurrence in San Diego Fm. — L.A.M. 124. S.D.
4413.

Original description. — Shell moderately arched,
coarse and thick, slightly longer than high. Right valve
ornamented by about 23 or 24 rounded to slightly flat-
topped ribs, separated by narrower, round-bottomed inter-
spaces, both the interspaces and ribs crossed by concentric
incremental lines, and, in some cases, by rather strong
lines of growth; anterior ear with a large byssal notch, and
sculpture consisting of about five or six radiating riblets,
crossed by concentric incremental lines; anterior and
posterior margins of valves smooth except for concentric
incremental lines; ventral margin rounded; posterior ear
ornamented by about eight radiating riblets and by lines
of growth, the posterior edge of the ear forming nearly a
right angle with the hinge line. Left valve convex, higher
at the umbo than the right valve, and ornamented by
about 24 or 25 squarish, flat-topped, rounded ribs,
separated by narrower, round-bottomed interspaces, the
whole valve sculptured by concentric lines of growth; ears
slightly concave, ornamented by about six or seven
radiating riblets. Altitude 90 mm, longitude 95 mm,
diameter of right valve approximately 15 mm; apical angle
of right valve, approximately 114°. (Hertlein.)

Remarks. — A large, well preserved specimen of
Chlamys hakei was collected at Pacific Beach by Dr. E. C.
Wilson, San Diego Society of Natural History. It is 152 mm
long, 135 mm high, the convexity (both valves together)
55 mm. It is sculptured with about 27 radial ribs and it
agrees in all shell characters with specimens from beds of
Pliocene age on Cedros Island. A large left valve in the
collections of the San Diego Society of Natural History,
from Juniper and Boundary streets, San Diego,is 160 mm
long, 142 mm high, convexity approximately 35 mm.
A fragment of an imperfectly preserved left valve in the
collections of the Los Angeles County Museum, which
came from strata 15 feet below Snyder’s Continuation
school in San Diego, is provisionally referred to C. hakei.

This species is characterized by its large, thick,
coarse valves which are sculptured with 24 to 27
subrounded radial ribs.

The shell of this species can be separated from other
somewhat similar west American species of Argopecten
by its large size when adult and by the more numerous
subrounded radial ribs. In the number of ribs it is ex-
ceeded by Chlamys (Argopecten) evermanni E. K. Jordan
and Hertlein (1926, p. 439, pl. 27, fig. 1) which has 30
to 31 flattish topped ribs separated by very narrow inter-
spaces. Chlamys hakei differs from C. cristobalensis
Hertlein (385) in the much wider and less elevated ribs.
Chlamys hakei differs from C. purpurata Lamarck (386)
now living from Paita, Peru, to Valparaiso, Chile, in the
generally larger size, larger ears, generally more numerous,
rounded ribs which are separated by narrower interspaces.
The ribs on the right valve of C. purpurata are flat-topped
and on both valves the ribs are separated by rather deeply
grooved interspaces, those on large left valves often with
an interstitial riblet.

Chlamys hakei can be easily separated from Chlamys

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

(Lyropecten) cerrosensis by the more numerous ribs, lack
of coarse hinge teeth, lack of midrib in interspaces and
also by the fact that the ears on the left valve slope down-
ward from the margin rather than forming a right angle.

In addition to the present record of Chlamys hakei
in beds of Pliocene age at San Diego, it occurs at Cedros
Island and at Bahia Tortolo (Turtle Bay), Lower California.
Grant and Gale recorded this species as occurring in beds
of Pliocene age one and one half miles west of Somis in
Ventura Co. but that record needs substantiation.

We are uncertain what species is represented by the
record of “Pecten purpuratus var.” cited by Woodring
(387) from beds of Pliocene age in Temescal Canyon, Los
Angeles Co., California, or by records of that species from
the same county which were listed by Oakshott (388),
and by Winterer and Durham (389). Vokes (390) re-
ported “‘Aequipecten purpuratus” from strata of late
Pliocene age and ‘‘Aequipecten cf. purpuratus” from beds
of Pleistocene age in the Santa Rosalia region in Lower
California. However, Durham, 1950, did not record that
species in collections from the Gulf of California region
studied by him nor, more recently, did Emerson and
Hertlein (Trans. San Diego Soc. Nat. Hist., Vol. 13, No.
17, pp. 333-338, 1964). It appears certain that records
of C. purpurata from western North America are
referable to some other species.

Chlamys (Argopecten) invalida Hanna
Plate 33, Figures 1, 3, 8

Pecten (Plagioctenium) cooperi Arnold, U. S. G. S., Prof.
Paper 47, p. 124, pl. 49, figs. 2, 3,4, 1906. San Diego
Formation, Pacific Beach, San Diego, Pliocene. —
Keen and Bentson, Geol. Soc. Amer., Spec. Papers No.
56, p. 83, 1944. Arnold’s record cited.

Pecten cooperi Arnold, J. P. Smith, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 9, No. 4, p. 151, 1919. “San Diego.”
Pliocene.

Not Pecten cooperi E. A. Smith, Fauna and Geography of
Maldive and Laccadive Archipelago, Vol. 2, Pt. 2, Moll.,
p. 621, pl. 36, figs. 15-18, 1903. Felidu Atoll,
Maldive Islands, in 1 to 35 fathoms.

Pecten invalidus Hanna, Proce. Calif. Acad. Sci., Ser. 4,
Vol. 13, No. 10, p. 177, March 18, 1924. New name
for Pecten cooperi Arnold, 1906, not P. cooperi E. A.
Smith, 1903. — Keen and Bentson, Geol. Soc. Amer.,
Spec. Papers No. 56, p. 88, 1944. “[San Diego,]
Pliocene. Pacific Beach, San Diego Co.”

Pecten (Plagioctenium) invalidus Hanna, E. K. Jordan and
Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No.
14, p. 441, 1926. ‘San Diego upper Pliocene of
southern California.” Also records from Lower Cali-
fornia.

Pecten (Aequipecten) deserti Conrad variety invalidus
Hanna, Grant and Gale, Mem. San Diego Soc. Nat. Hist.,
Vol. 1, p. 213, 1931. “Pacific Beach, San Diego (Arnold;
Hertlein and Grant).”’ Pliocene.

Aequipecten circularis invalidus Hanna, Woodring, Stewart,
and Richards, U. S. G. S., Prof. Paper 195, table opp.
p. 112, 1940 (1941). Pacific Beach, San Diego, Cali-
fornia, Pliocene.

Aequipecten invalidus Hanna, Vedder, U. S. G. S., Prof.
Paper B-400, p. B327, 1960. “San Diego formation.”
Also Niguel Formation and others.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Type specimen. — No. 8, Stanford University,
Department of Geology, Type Collection.

Type locality. — “San Diego formation (Pliocene),
Pacific Beach, San Diego County, Cal.”

Range. — Middle Pliocene of San Diego, California,
and northwestern Lower California.

Occurrence in San Diego Fm. — C.A.S. 104, 105,
1130, 1132, 1138, 1179, 1199, 1399, 1413, 12145,
34025. L.A.M. 122. U.C.L.A. 302, 2420.
three miles south of La Jolla, Pacific Beach; Locs. 105;
1130, 1138, [Sternberg’s Loc. 3]; 1199; 12145; 35025
Pacific Beach; Loc. 1132, above Loc. 1130; Loc. 1179,
upper portion of lower beds exposed in Pliocene section

Original description of Pecten (Plagioctenium)
cooperi Arnold. — Shell averaging about 30 millimeters in
altitude, slightly longer than high, both valves moderately
convex, disks slightly obliquely produced posteriorly,
moderately thick; disk generally characterized by several
more or less prominent concentric zones of interrupted
growth, which show as color bands even on the fossil
Shells; sides nearly straight; margins serrate. Right valve
with 18 to 20 flat-topped, squarish ribs, which tend to
flatten out and become more convex topped in the later
stages of growth; interspaces narrower than the ribs,
and crossed on the bottom by numerous, fine, sharp, in-
cremental lirulae, which become obsolete on the ribs ex-
cepting in the later stages of growth; hinge line somewhat
more than one-half length of disk; anterior ear slightly
produced and ornamented by 4 or 5 prominent radials
and numerous incremental lines; byssal notch deep and
sharply defined; posterior ear slightly truncated, and
sculptured by obsolete radials and fine incremental lines.
Left valve similar to right, except that the ribs are
narrower and the interspaces correspondingly broader.
Dimensions: Alt. 30 mm; long. 31 mm; hinge line 17 mm;
diameter 12 mm; umbonal angle 95°. (Arnold.)

Remarks. — A number of specimens all from Pacific
Beach, the type locality of Chlamys invalida, agree in all
shell characters with the type specimen.

Valves of this species are characterized by their low
convexity and by the character of the ribs, 18 to 20,
which are square in the early stages but which widen
out and become more convex toward the ventral margin.
The interspaces often are ornamented with well developed
concentric imbrications.

A typical right valve from Loc. 1179 (CAS),
Pacific Beach, is 35.2 mm long, 33.5 mm high, con-
vexity (one valve) 9 mm, umbonal angle 95°. Two large
right valves, from Loc. 105 (CAS), the larger 47.9 mm
long and 46.8 mm high, agree with valves of Chlamys
invalida except that they are larger and have a greater
number of ribs, 21 to 22. These valves appear to be
referable to large gerontic forms of C. invalida.

The smaller shell, more rounded outline, fewer ribs
which become broader and more rounded toward the
ventral margin, occasional concentric zones of interrupted
growth, and smaller umbonal angle are features which
serve to separate this species from Chlamys callida.

The generally smaller more orbicular shell and fewer

ribs which become decidedly broader and more convex
but not obsolete near the margin are characteristics which
serve to separate C. invalida from ‘‘Aequipecten”
antonitaensis Durham (391) which was described from
beds of middle Pliocene age at Punta Santa Antonita on

201

the east coast of Lower California.

Chlamys invalida has also been reported from Cedros
Island and the west coast of Lower California. Records of
it in the Gulf of California region are, in most cases, open
to doubt. Specimens from beds of Pliocene age in the
Los Angeles region which were attributed to this species
by Grant and Gale (1931, pl. 5, figs. 5a, 5b, 5c, 6a, 6b,
6c) are not typical of C. invalida but bear a greater
resemblance to some forms of C. deserti Conrad or of C.
circularis

Chlamys (Argopecten) coopericellus Ferreira (392),
described from strata of early Miocene age in Brazil, was
compared by its author with “C. (A.) cooperi (Arnold,
1906)” [= Pecten invalidus Hanna]. A small riblet is
present in the interspaces between the ribs of the Brazilian
species and in this and in other details it is quite distinct
from C. invalida.

Kryshtofovich (393) reported “Pecten cooperi” as
occurring in the “Upper oil bearing series” of Pliocene
age on Sakhalin Island, but that record doubtless is
referable to some oriental species.

Chlamys (Argopecten) subdola Hertlein
Plate 30, Figures 7, 8; Plate 35, Figures 2, 5, 9

Pecten (Plagioctenium) subdolus Hertlein, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 14, No. 1, p. 20, pl. 5, figs. 2,
4, 7, July 31, 1925. — E. K. Jordan and Hertlein,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 443,
1926. “San Diego upper Pliocene of Pacific Beach,
Calif.”” — Keen and Bentson, Geol. Soc. Amer., Spec.
Papers No. 56, p. 94, 1944. Earlier records cited. —
Hertlein and Grant, State Calif. Div. Mines, Bull. 170,
Chapt. 2, p. 60, 1954. ‘“‘San Diego formation.”

Pecten (Aequipecten) purpuratus Lamarck variety subdolus
Hertlein, Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 211, pl. 5, fig. 1 (west of San Fernando
Pass, Los Angeles Co.), 1931. “San Diego (Hertlein;
Jordan and Hertlein; Hertlein and Grant).”

Pecten subdolus Hertlein, Hertlein and Grant, Calif. Jour.
Min. Geol., Rept. State Mineral. 35, p. 69, 1939.
Upper beds in Pliocene section at Pacific Beach. —
Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, pp. 57, 59. Pacific Beach; Market Street
one-tenth mile east of Euclid Avenue, San Diego,
Pliocene.

Pecten (Argopecten) subdolus Hertlein, Moore, San Diego
Soc. Nat. Hist., Occas. Paper 15, p. 50, pl. 23, figs. a,
b, 1968. Pacific Beach, Pliocene.

Type specimen. — No. 51, Stanford University,
Department of Geology, Type Collection.

Type locality. — “Pacific Beach, San Diego, Cali-
fornia.” “San Diego, Pliocene.”

Range. — Middle Pliocene of southern California
and northern Lower California.

Occurrence in San Diego Fm. — C.A.S. 104, 105,
1132, 1182, 1183, 1401, 1413, 12145, 28880, 33334.
L.A.M. 107, 122, 127, P.87: No. 58339. S.D. 5, 80,
365, 408. U.C.L.A. 300, 302, 2359.

Original description. — Shell of medium size, the
valves moderately convex. Right valve ornamented by
about 21 rounded, radiating ribs which become broader
toward the ventral margin, the ribs separated by round-
bottomed, narrower interspaces, the whole surface

202

ornamented by very fine radial striations and by con-
centric lines of growth; anterior and posterior margins
sculptured only by concentric incremental lines; ventral
margin rounded; ears unequal, the anterior with a well
defined byssal notch, and sculpture of about six radiating
riblets crossed by incremental lines; the posterior also
sculptured by about six or seven slight radiating riblets
crossed by lines of growth, a very slight notch present.
Left valve more arched than right and somewhat one-
sided in appearance, ornamented by about 21 rounded,
radiating ribs separated by round-bottomed interspaces
about as wide as the ribs, the whole surface finely
longitudinally striate and crossed by concentric lines of
growth; ears slightly concave, the posterior sculptured by
very slight radiating riblets and concentric lines of
growth, the anterior with a rounded notch, the surface
sculptured by a few slight radiating riblets and by con-
centric growth lines, the ornamentation indistinct on
weathered specimens. Altitude 50 mm, longitude 50 mm,
diameter approximately 17 mm, apical angle in each valve
approximately 105°. (Hertlein.)

Remarks. — This species occurs rather abundantly
in the San Diego Formation, especially at Pacific Beach.
One of the largest specimens from Loc. 1401 (CAS),
south slope of Mount Soledad, is 64.2 mm long, 61 mm
high, convexity (both valves together), 23 mm, length of
hinge, approximately 32 mm, umbonal angle 105°.

The shell of Chlamys subdola resembles that of C.
callida, with which it occurs, in outline and in general
pattern of sculpture. It differs from the latter species in
possessing a thinner shell, in the low rounded ribs, the
presence of radial striae on the disk, and weaker sculpture
on the ears.

Specimens of Chlamys subdola closely resemble
some individuals of Chlamys impostor Hanna (394). We
have examined a large series of C. impostor and it is
evident that there is considerable variation in that species
with respect to number of ribs (20 to 24), the elevation
and degree of roundness of the ribs and in the umbonal
angle. The largest specimens usually do not exceed 46 mm
in altitude.

In comparison to Chlamys impostor, the shell of
Chlamys subdola is thinner, it attains a greater size
(altitude 50 to 61 mm), the ribs, of which there are
usually fewer, are flatter and become broader toward the
ventral margin, the ears are a little larger, and the ribs on
the left valve are finer.

Grant and Gale (1931, p. 214) considered Chlamys
impostor to be a variety of Chlamys deserti Conrad (395),
whereas Woodring and Stewart (396) considered it to be a
subspecies of Chlamys circularis Sowerby. Whatever the
true relationship may be, there is a striking resemblance
between some specimens of Chlamys impostor and those
of C. subdola. However, the differences observed in
series of the two lead us, at least for the present, to retain
C. subdola as a species rather than a subspecies of C.
impostor. Grant and Gale considered Chlamys subdola
to be a variety of C. purpurata Lamarck. The differences
between the two are obvious.

“Aequipecten”’ revellei Durham (Geol. Soc. Amer.,
Mem. 43, Pt. 2, p. 63, pl. 9, figs. 6, 9, 1950) described
from strata of Pliocene age on Monserrate Island, in the
Gulf of California, bears a resemblance to C. subdola,
but differs in the more rounded outline and proportionally

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

longer hinge line.

There is a general similarity in the outline and
sculpture between Chlamys subdola and C. eborea
senescens Dall (397) and the form walkerensis Tucker
(398), which Tucker-Rowland later placed in the syn-
onymy of C. eboreus senescens Dall. There are differences
between the east and west coast species, such as in the
shape of the posterior ear, and the relationship, if any, is
unknown. Another species bearing a resemblance to C.
subdola is C. imitata Weisbord (399) which was described
from strata of Pliocene age in Venezuela.

In addition to its occurrence in the San Diego
Formation, Chlamys subdola has been recorded by Grant
and Gale (1931, p. 211) from “middle Pico” beds west
of Fernando Pass in Los Angeles County, California. To
the south it occurs abundantly at Cedros Island and it also
occurs in Pliocene beds on the adjacent mainland of
Lower California. Vokes (400) recorded it as occurring in
beds of Pliocene age in the Santa Rosalia area on the east
coast of Lower California but later authors have not
reported it from the Gulf of California region.

SUBGENUS LEPTOPECTEN VERRILL

Leptopecten Verrill, Trans. Connecticut Acad. Arts Sci.,
Vol. 10, Pt. 1, p. 69, June, 1890. — Grau, Allan
Hancock Pac. Exped., Vol. 23, p. 105, 1959. Type
designation by monotypy.

Type species (by original designation). — “Type,
C. monotimeris (Conrad)” [= Pecten monotimeris Conrad,
Jour. Acad. Nat. Sci Philadelphia, Vol. 7, p. 238, pl. 18,
fig. 10, 1837. ‘‘Inhabits with the preceding”’] [which is,
“Inhabits below the efflux of the tide near Sta. Diego and
Sta. Barbara.”’] “The young occasionally found attached
to Fuci by a slender byssus.”’ Illustrated by I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 57,
pl. 40, figs. 1 and 2, 1924. [These are not copies of
Conrad’s illustrations although stated to be so by Oldroyd. |
See also Grau, 1959, p. 110, pl. 35, fig. 2.

Range. — Early Miocene to Recent. Recent from
the intertidal zone to 219 meters (120 fathoms).

Description. — Shell thin, translucent, oblique,
broadly rounded, with strong, rounded radial ridges or
folds, like corrugations, which appear in reverse on the
interior surface. The internal ribs are not angulated by a
deposit of the shell, nor distinctly thickened. Margin with
broad scallops. The exterior surface is covered with fine
divergent camptonectes sculpture, both on the ribs and
intervals. The ribs do not increase in number with age,
but become broader and more flattened. Auricles large
and broad, thin, corrugated. Byssal notch large and deep.
Pectinidial teeth prominent. Hinge-plate thin and but little
differentiated. Cardinal ridge thin and small, close to the
ligament, crossed by fine incisions. The resilal pit is
small, close to the ligament, crossed by fine incisions.
The risilial pit is small, but projects beyond the thin hinge-
plate in the left valve. (Verrill.)

This is a peculiar group, remarkable for its thin
but strongly corrugated oblique shells, with fine camp-
tonectes sculpture. (Verrill.)

Remarks. — About a dozen west American late
Cenozoic species and subspecies are referable to Lepto-
pecten. These small, thin, oblique shells differ sufficiently
from those of Aequipecten and Argopecten to justify the

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

recognition of Leptopecten as a distinct subgenus.

The Pecten andersoni group which occurs in beds of
Miocene age in western North America can be assigned to
Leptopecten. Several species in the late Cenozoic of
northern South America and in the Caribbean region also
are referable to this subgenus. Among these are Pecten
atlanticola Anderson and P. macloskeyi Anderson from
Miocene beds in Colombia, and P. bavayi Dautzenberg and
Pecten linki Dall living in the Caribbean.

Some of the species assigned to Leptopecten attain
considerable size. Grau (written comm., March 1, 1965)
mentioned that a large specimen of C. (L.) monotimeris
from off an oil well platform off Summerland, California,
is 49 mm long and 43 mm high.

Pecten (Leptopecten) praevalidus E. K. Jordan and
Hertlein (401) described from beds of Pliocene age near
Bahia Tortolo (Turtle Bay), Lower California, attains a
length of 50 mm, height 48 mm, and length of hinge line,
48 mm. In general appearance this species is remarkably
similar to Chlamys sacyi Cossmann and Peyrot (402)
described from beds of Burdigalian, Miocene age in
France. The latter species is the type species of Antipecten
Cossmann in Cossmann and Peyrot (403), which appears to
differ from Aequipecten in the obliquity of the hinge line,
larger ears, and in the unequal size of the ribs on the left
valve.

Key to Species of Leptopecten

A. Ribs narrow, sharply topped;

interspaces wider than the ribs bellilamellata
B. Ribs squarish, flat topped;

interspaces about as wide as the

ribs - latiaurata

Chlamys (Leptopecten) bellilamellata Arnold
Plate 32, Figures 1, 2, 8

Pecten (Chlamys) bellilamellatus Arnold, U. S. G. S., Prof.
Paper 47, p. 108, pl. 41, figs. 6, 6a, 7, 7a, 1906. —
Arnold, in Eldridge and Arnold, U. S. G. S., Bull. 309,
p. 252. pl. 40, fig. 14, April, 1907. ‘Pliocene, Pacific
Beach, San Diego.” — Arnold, Proc. U. S. Nat.
Mus., Vol. 32, No. 1545, p. 546, pl. 50, fig. 14, June
15, 1907. “Pliocene, Pacific Beach, San Diego.” —
Keen and Bentson, Geol. Soc. Amer., Spec. Papers No.
56, p. 81,1944. Records by Armold cited.

Pecten (Aequipecten) bellilamellatus Arnold, Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 205,
1931. “Pliocene: Pacific Beach, San Diego (Arnold).”

Type specimen. — No. 35, Stanford University,
Department of Geology, Type Collection.

Type locality. — “Pliocene at Pacific Beach, San
Diego, California.

Range. — Middle Pliocene at Pacific Beach, San
Diego, California; Cedros Island, Bahia Tortola (Turtle
Bay) and Elephant Mesa, Lower California.

Occurrence in San Diego Fm. — C.A.S. 1400. S.D.
331.

Original Description. — Shell averaging about 18
millimeters in altitude, about as long as high, equivalve,
both valves moderately convex, inequilateral; sides nearly

203

straight; margins not serrate. Right valve with 15 or 16
prominent narrow, sharply convex-topped ribs with
sloping sides; interspaces much wider than ribs, with
narrow, flat bottoms; surface sculptured by numerous,
regular, equidistant, thin, concentric, imbricating lamellae,
which cut squarely across the bottoms of the interspaces,
curve convexly toward the umbo on the sides of the ribs,
and loop gracefully downward away from the umbo on
the tops; hinge line equal to the length of the disk; ears
equal in length; anterior ear convexly truncated, separated
from the disk by a deep, sharply defined, byssal notch,
and sculptured by fine, regular, incremental lamellae and
five or six subequal radials; posterior ear acutely pointed,
radially striate, and with incremental sculpture similar to
but not quite as prominent as that of the anterior. Left
valve similar to the right; anterior ear more prominently
sculptured, both radially and concentrically, than the
posterior. Dimensions. Alt. 18 mm, long. 18 mm, hinge
line 18 mm, diameter 8 mm, umbonal angle 100°.
(Arnold.)

“This species is characterized by its small size when
adult, long hinge line, narrow, sharply topped ribs and
beautifully curved incremental lamellae”. (Arnold.)

Remarks. — The characters enumerated by Arnold
easily serve to separate this species from Chlamys (Lepto-
pecten) latiaurata Conrad and its subspecies C. (L.)latiaurata
delosi Arnold. (404).

Two left valves from strata of Pliocene age at Pacific
Beach in the collections of the California Academy of
Sciences are referable to Chlamys bellilamellata. The
larger one is 16.6 mm long, possesses 14 high, sharp-
topped radial ribs which show traces of concentric im-
brications. The other is a small valve 12.8 mm long
which has but 13 narrow, sharp-topped, widely separated
ribs which likewise show traces of concentric imbrications.

A small right valve from Loc. 331 (SD), from near
the Mexican boundary is 14.6 mm long and 13.7 mm high,
appears to be referable to the present species. There are
about 13 sharply rounded ribs which are wider than the
interspaces. The posterior ear is imperfect but the growth
lines indicate an auricle similar to that of C. (L.)
bellilamellata.

Three small valves and one large right valve 16.3 mm
high and 16.5 mm long were collected in the upper portion
of the Pliocene strata exposed at Pacific Beach.

Webb (405) reported the occurrence of this species
in beds of Pleistocene age at Point Loma Peninsula,
California, but we have not seen specimens.

Chlamys (Leptopecten) desultoria Weisbord (406),
described from beds of Pliocene age in Venezuela, was
compared by its author with C. (L.) bellilamellata from
which it differs in possessing a radial thread in the inter-
spaces.

Chlamys (Leptopecten) latiaurata Conrad
Plate 35, Figures 1, 3

Pecten latiauratus Conrad, Jour. Acad. Nat. Sci. Philadel-
phia, Vol. 7, Pt. 2, p. 238, pl. 18, fig. 9, 1837.

Pecten tunica Philippi, Abbild. u. Beschreib. Conchyl., Bd.
1, Heft 4, Pecten, p. 100 (2), pl. 1, fig. 3, January,
1844. “Habitat ad Insulas Sandwich.” [Locality
erroneous. |

Pecten latiauritus Conrad, Kobelt, Conchyl. -Cab. von

204

Martini und Chemnitz, Bd. 7, Abt. 2, p. 203, pl. 54,
figs. 7, 8, 1888. ‘“‘an der Westkuste von Nordamerika,
besonders an Californien.” — I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 57
(under section Leptopecten), pl. 22, fig. 2, 1924.
“Monterey, California, to the Gulf of California,”
Recent. [Reproduction of Conrad’s original figure of
P. latiauratus. |

Pecten (Chlamys) latiauritus Conrad, Arnold, U. S. G.S.,
Prof. Paper 47, p. 115, pl. 46, figs. 2, 2a, 3, 3a, 1906.
Pliocene to Recent.

Chlamys (Leptopecten) latiaurata Conrad, Grau, Allan
Hancock Pac. Exped., Vol. 23, p. 107, pl. 35, fig. 1,
1959. Earlier records cited.

Type specimen. — Two syntypes in British Museum
(Natural History), Nos. 55.3.14.53 and 61.5.20.89 (A. M.
Keen, Veliger, Vol. 8, No. 3, p. 169, 1966).

Type locality. — “Inhabits below the efflux of the
tide near Sta. Diego and Sta. Barbara.” [California.]
“Type locality: San Diego, California” (Grau).

Range. — Middle Pliocene to Recent. Recent from
Point Reyes, California, to Cape San Lucas, Lower Cali-
fornia, Mexico. Also Guadalupe Island. Reported from 1
foot (minus tide) to 229 meters (125 fathoms). Found
attached to rocks or pilings in shallow water; in deeper
water on rock, shale, gravel, or sand bottoms, often
attached to calcareous algae. (Grau.)

Occurrence in San Diego Fm. — S.D. 331. U.C.L.A.
312.

Original description. — Shell inequilateral, thin,
compressed; ribs fourteen, flattened on the back, slightly
suleated; interstices transversely striated; ears very wide,
unequal, both acutely angulated at the extremity; colour
reddish brown and white, variegated or spotted. (Conrad.)

A series of specimens reveals that the number of ribs
may vary from 12 to 16. Some of these may be faintly
medially sulcated. A faint intercalary riblet may be
present in the interspaces especially on large specimens.

Remarks. — Three right and one very small left valve
of this species are present in the collection from Loc.
312 (UCLA). The largest specimen, a right valve, is 16.9
mm long and 17.5 mm high. One small right valve 14.6
mm long was collected at Loc. 331 (SD). A large Recent
specimen of this species in the collections of the
California Academy of Sciences collected by H. N. Lowe
at Long Beach, California, is 33.8 mm long, 31 mm high,
convexity (both valves together), 11.9 mm, length of
hinge, 28 mm.

This is the first record of the occurrence of Chlamys
(Leptopecten) latiaurata in the San Diego Formation.
Woodring (407) questioned Arnold’s record of the occur-
rence of this species in the Third Street tunnel in Los
Angeles. However, it has been recorded from beds of
Pliocene age elsewhere. Arnold (408) reported it from
the “lowest Merced horizon developed in the Santa Cruz
quadrangle” and E. K. Jordan and Hertlein (409) recorded
it from beds of Pliocene age at Cedros Island and at Bahia
Tortolo (Turtle Bay), Lower California.

Chlamys (Leptopecten) latiaurata differs from C.
(L.) monotimeris Conrad in the squarish ribs rather
than rounded undulations of the shell.

A species described from the Gulf of California,
Aequipecten (Leptopecten) camerella Berry (410), is said
to resemble C. (L.) latiauratas but “differing chiefly in its

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

smaller size, plumper more rounded form, smooth intervals
between the radii of the disk, and lighter coloring.”

Ferreira (411) reported a species under the name of
“Chlamys (Leptopecten) cf. latiaurata” from beds of
early Miocene age in Brazil. Judging solely from the
illustrations, the Brazilian form resembles some species of
Leptopecten described from the late Cenozoic of the
Caribbean region more closely than it does the west
American species.

Aequipecten (Leptopecten) cracens Olsson (412),
described from strata of Miocene age in Ecuador, is
sculptured with 17 coarsely noded radial ribs.

The present species, C. (L.) latiaurata, commonly
known as “kelp-pecten”, occurs at many places along the
coast of southern California attached by its byssus to
vegetable growths, pilings, or rocks. It occurs in shallow
water but it has been taken at a depth of 229 meters
(125 fathoms). Coe (413) discussed the growth and
reproduction of this species. It reaches maturity in
about 9 to 12 months and in that period of time attains
a length of about 32 mm.

Formerly it flourished in the still, warm waters of
Mission Bay (414), San Diego Co., where it lived attached
to Zostera.

SUBGENUS SWIFTOPECTEN HERTLEIN

Swiftopecten Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol.
21, No. 25, p. 319, September 26, 1935. “the type of
which is P. swiftii Bernardi.”” — Hertlein, Nautilus,
Vol. 50, No. 1, p. 24, July 14, 1936. “Type: Pecten
swiftii Bernardi.”

Type species (by original designation.) — Pecten
swiftii Bernardi [Journ. de Conchyl., Vol. 7, p. 90, pl. 1,
fig. 1; pl. 2, fig. 1, July, 1858. “Hab. la baie Nicolas, dans
la Manche de Tartarie.” — Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, pl. 10, figs. 1a, 1b, 1931.
(Reproduction of original figures of Bernardi.) — Masuda,
Trans. Proc. Palaeo. Soc. Japan, N. S., No. 34, pp. 86-96,
pl. 9, 1959.]

Range. — Late Miocene (Stanton) to middle
Pliocene in California; mid-Miocene to Pleistocene in
Alaska; early Miocene to Recent in Japan. Recent in
from 1 to 143 meters (1 to 78 fathoms).

Description. — Shell of medium size, higher than
long, nearly equivalve, ears well developed, the right the
larger and with a deep byssal sinus and a ctenolium; right
valve sculptured with 4 or 5, or occasionally more, large,
coarse, rounded radial ribs (paired in some species),
formed by corrugations of the shell, the left valve similar
but with smaller ribs; valves usually with concentric
undulations which form node-like areas on the ribs of the
left valve; entire surface of valves and ears ornamented with
rather coarse radial riblets, and the exterior surface super-
ficially microscopically tessellated; hinge of right valve
with an elevated ridge on each side of the ligamentary pit
and fitting into two corresponding grooves in the hinge of
the left valve; margin reflects the major exterior sculpture.

Remarks. — The members of Swiftopecten all have
valves of nearly equal convexity, the left more so, and are
chlamydoid in shape. The few coarse ribs where crossed
by concentric undulations are thickened and give rise
to node-like ornamentation. The character of the hinge
with the two ridges, one on each side of the ligamentary

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

pit on the right valve and corresponding depressions on
the left, bring to mind the observations of Beyrich and
Futterer concerning correlation of the ribbing and the
hinge of Neithea. Futterer (415) stated that “Hand in
Hand mit dem Vorhandsein dieser 2 Zahne geht die
ausbildung eines 6-strahligen Baues in der Schalensculptur.”

Concentric undulations somewhat similar to those
on Swiftopecten occasionally occur on some species of
Lyropecten such as those on Chlamys (Lyropecten)
crassicardo and on C. (L.) estrellana and those on the
Floridan C. condylomata Dall, an east American Miocene
species. Node-like sculpture somewhat similar to that on
Swiftopecten also is present on species of Nodipecten such
as on C. (N.) nodosa Linnaeus, C. (N.) subnodosa Sowerby
and C. (N.) nodulifera Sowerby.

Typical members of Swiftopecten made their first
appearance in Japan in early Miocene and in western North
America in strata of middle Miocene age in southeastern
Alaska. In California this group of scallops first appear in
beds of late Miocene age (Castaic Formation). Individuals
occur abundantly in beds of middle Pliocene age in
Lituya Bay in southeastern Alaska, in California from
Crescent City to San Diego, and in Lower California on
Pliocene terraces east of San Quintin, and at Bahia Tortolo
(Turtle Bay). A species of Pleistocene age, C. (S.) kindlei
Dall, occurs in terrace deposits east of Nome, Alaska.

A species known to occur in beds of Miocene age in
California, believed by some authors to bear relationship
to members of the Swiftopecten group is the form
described by Arnold as Pecten (Chlamys) hamlini (416).
The type, a right valve, is, as mentioned by Arnold, a
distorted specimen. We have examined a cast of the type
specimen. It possesses 4 broad ribs each of which are
radially grooved forming 5 radiating ridges. This rare
species may be related to the Swiftopecten group or it may
be referable to some other group with radially grooved
ribs. Species such as Pecten praevasseli de Bockh and
Richardson (417) in Douglas, a Persian species, have
somewhat similar ribbing though no real relationship to
such species is here suggested. The relationship, if any,
of P. hamlini with other Californian species is not known
at the present time.

The specimen of late Miocene age from California
illustrated by Adegoke (Veliger, Vol. 9, No. 3, pp. 337-
339, pl. 47, figs. 1 and 2, 1967) under the name of
“Swiftopecten spec.” , appears to be a juvenile Lyropecten.

Several species and subspecies of Swiftopecten have
been described from Japan, Kamtschatka, and western
North America. This group had its origin in the northern
Pacific where the greatest number of extinct forms have
been described and where the single Recent species,
C. (S.) swiftii, has been recorded as occurring from late
early Miocene to Recent in Japan.

Matsumoto suggested that the Miocene species
described by him as Pecten natoriensis (418) is an ancestral
form of C. (S.) cosibensis Yokoyama. Hatai and Nisiyama
(419) in 1935 discussed the relationship of C. (S.)
cosibensis Yokoyama, C. (S.) heteroglypta Yokoyama
and C. (S.) swiftii. They believed, correctly we think, that
the two former forms are distinct from C. swiftii and its
American relatives with whose synonymy they were in-
volved by Grant and Gale. Later Hatai and Nisiyama (420)
called attention to the similarity of C. natoriensis and the
form described by Arnold as Pecten (Chlamys) nutteri.

205

The shells of C. (S.) cosibensis and C. (S.) heteroglypta,
especially during their earlier geological occurrences, are
smaller than C. (S.) swiftii. Furthermore they have more
ribs which are more nearly equal in size than those of
C. (S.) swiftii. These facts together with the observation
of Hatai and Nisiyama that in their early stages these
species reveal a tendency to be more circular in outline,
all point toward a specialized development from a chlamyd
form. More recently Masuda (1962) referred C. cosibensis
and C. heteroglypta to Chlamys s. s., an assignment not
convincing to us.

Hatai and Masuda described a genus, Nanaochlamys
(421), based upon Pecten notoensis Yokoyama. In the
synonymy of this species they placed the forms named by
Matsumoto as Pecten natoriensis, P. n. subovalis, and
P. n. inequilateralis. The shell characters of their new
new genus were compared with those of Mesopeplum
Iredale and Scaeochlamys Iredale. Later Masuda (1962,
p. 196) stated that Nanaochlamys is closely related to
Swiftopecten but differing in “its orbicular symmetrical
shell, surface sculpture, shape of auricles and indistinct
ctenolium.” He gave the range of Nanaochlamysas late
Oligocene to Miocene.

Some authors have considered the type species of
Nanaochlamys to be an ancestral member of the Swifto-
pecten group. If subsequent studies confirm this relation-
ship, then Nanaochlamys would have little significance as a
supraspecific taxonomic unit. According to MacNeil
(U. S. G. S., Prof. Paper 553, p. 11, 1967), the left valve
of N. notoensis is flat or slightly concave in the juvenile
stage and this he believes is evidence opposed to close
relationship to Swiftopecten.

The line of development indicated by members of
Swiftopecten is quite distinct from that of Decatopecten,
Manupecten and Semipallium, with which, at times, mem-
bers of Swiftopecten have been placed. These subgenera
include shells which are sculptured with a few coarse
radially striated ribs.

Decatopecten Ruppel in Sowerby (422), type
Pecten plica Linnaeus, includes shells of medium small
size of which the right valve is a little more convex than
the left, the hinge is short, byssal sinus very slight, and the
hinge armature consists of perpendicular tooth-like plaits.

This subgenus occurs from Pliocene to Recent in
the north Pacific, East Indies, and Red Sea region, in the
post-Pliocene of east Africa and Recent from Japan to the
Red Sea.

Anguipecten Dall, Bartsch, and Rehder (423), has
hinge characters similar to those of Decatopecten, but
the hinge line is shorter and the external sculpture con-
sists of many nearly equal, rounded, radial ribs. It is
represented in the Miocene of New Caledonia and Recent
in Hawaii, Japan and the western Pacific.

Manupecten Monterosato (424), type Pecten pesfelis
Linnaeus, occurs from mid-Miocene to Recent in the
Mediterranean region and in Miocene and Pliocene strata
in the Red Sea region. It lacks concentric undulations of
the shell as well as a low ridge on each side of the liga-
mental pit of the right valve such as occur on Swiftopecten.
In the character of the hinge and in some details of the
sculpture Manupecten bears a closer resemblance to
Chlamys than it does to Swiftopecten. Felipes Locard in
Carus (425), is a synonym of Manupecten as it has the
same type species.

206

Semipallium Jousseaume (426), type Pecten tigris
Lamarck, bears a close resemblance to Manupecten, but in
the former group the left valve is generally consistently
flatter than the right one. This character as well as the
lack of concentric undulations on the left valve and the
smaller size, easily serve to separate the members of this
group from those of Swiftopecten. Semipallium occurs in
the northern and western Pacific and Indian Ocean region.
It is known to range from Miocene to Recent.

It is obvious that Swiftopecten is not closely allied
to these groups nor to others which resemble it only in
that they possess a few coarse radial ribs, such as
Mesopeplum Iredale (427), Notochlamys Cotton (428),
Anatipopecten Hertlein (429), and Stralopecten Rowland
(430).

Chlamys (Swiftopecten) parmeleei Dall
Plate 31, Figure 5; Plate 37, Figures 1-10
Text Figure 10

Pecten (Chlamys) parmeleei Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 4, p. 708, pl. 37, figs. 14, 14a, April,
1898. ‘Pliocene of San Diego, California; Parmelee.”
— Schuchert, Dall, et al., U. S. Nat. Mus., Bull. 53,
Pt. 1, p. 490, 1905. Original locality cited. — Arnold,
U. S. G. S., Prof. Paper 47, pp. 28, 100, 119, pl. 41,
figs. 1, la (copies of original figures), “San Diego
formation (Pliocene, Pacific Beach, San Diego County,
Cal.)”’, figs. 5, 5a (“‘Pliocene, Crescent City, Del Norte
County, Cal.’’), 1906. — Arnold, in Eldridge, U.S. G. S.,
Bull. 309, p. 244, pl. 36, fig. 7, 1907. Type specimen
illustrated and type locality cited. Also Pliocene of
Puente Hills, southern California. — Keen and Bentson,
Geol. Soc. Amer., Spec. Papers No. 56, p. 92, 1944.
Earlier records cited.

Pecten parmeleei Dall, Dall in Diller, U. S. G. S., Bull.
196, 1902. P. 32, wharf at Crescent City, -p. 39,
“same age as that at San Diego.” Pliocene. — J. P.
Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4,
pp. 150, 151, 1919 (as Pecten parmaleei). ‘“‘San Diego,”
Pliocene. — Hertlein, Stanford Univ. Bull., Ser. 5, No.
78, p. 85, 1929. “Pliocene” ‘‘San Diego fauna.” —
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.
1, p. 172. ‘Pliocene of San Diego.”

Pecten (Pallium) swiftii Bernardi form parmeleei Dall,
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.
1, p. 900, pl. 10, figs. 2, 5 (Holser Canyon, Los Angeles
Co., Calif., Pliocene), 1931.

Pecten (Swiftopecten) parmeleei Dall, Hertlein and Grant,
Calif. Jour. Min. Geol., Rept. 35, Calif. State Mineral.,
p. 69, 1939. ‘‘south slope of Soledad Mountain the
San Diego formation.” — Hertlein and Grant, Mem.
San Diego Soc. Nat. Hist., Vol. 2, p. 56, “Pliocene
strata at Pacific Beach,” p. 57, “south sloping spurs of
Mount Soledad,” p. 59, “near the Mexican Boundary
about three-quarters of a mile from the sea,” 1944. —
Hertlein and Grant, Calif. State Div. Min., Bull. 170,
Chapter II, p. 60, 1954. “San Diego formation.”
“middle Pliocene or early upper Pliocene age.”

Chlamys parmeleei Dall, Stewart, in Woodring, Stewart,
and Richards, U.S. G.S., Prof. Paper 195, p. 91, 1941.
Pliocene at San Diego. — Woodring in Woodring and
Bramlette, U. S. G. S., Prof. Paper 222, pp. 65, 83,

103 (Jacalitos and upper part of San Joaquin), 104

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

(Pacific Beach and inland, San Diego, Calif., Pliocene),
106, pl. 16, fig. 20 (Fugler Point, Santa Maria district,
Calif., Pliocene), 1950. — Vedder, U. S. G. S., Prof.
Paper 400-B, p. B3827, 1960. ‘San Diego formation.”
Also Niguel Formation and others.

Chlamys etchegoini parmeleei Dall, Woodring, Stewart,
and Richards, U. S. G. S., Prof. Paper 195, table opp.
p. 112, 1941. Pacific Beach, San Diego.

Type specimen. —Holotype, No. 154,479 United
States National Museum.

Type locality. — ‘Pliocene of San Diego, California.”

Range. — Late Miocene (Stanton); middle Pliocene,
from southeastern Alaska to Bahia Tortolo (Turtle Bay),
Lower California.

Occurrence in San Diego Fm. — C.A.S. 957, 1401,
1413, 12147. L.A.M. 107, 116, 305, 305A, 318. Strata
exposed in 1600 block, Larwood drive and Veya Court,
Encanto. S.D. 38, 80, 408, 2916, 4735. Redwood Street
and Swift Canyon. U.C. A-8333. U.C.L.A. 294.

Original description. — This species is close to P.
Swiftii Bernhardi of Japan (J. de Conchyl., vii., plates 1
and 2, 1858) but smaller, and differs by the smooth top
surface of the ribs, which in P. Swiftii are more or less
striated or coarsely threaded, and by the not alternated
radial riblets on the right posterior ear; also, especially, by
the profuse coalescent microscopically checkered squama-
tion, which makes a complete external coating to the
valve. Alt. 45, lat. 38 mm. (Dall.)

Text Fig. 10. Chlamys (Swiftopecten) parmeleei Dall.
Hypotype (Cat. No. 4735, San Diego Society of Natural
History), right valve, from India and Spruce streets, San
Diego; Pliocene. Length 64.8 mm. (Drawn by E. H.
Quayle.)

Remarks. — About 150 specimens of Chlamys
(Swiftopecten) parmeleei are present in collections ob-
served by us from the San Diego Formation from the south
slope of Mount Soledad, Pacific Beach, in San Diego, and
near the Mexican boundary. Most of these are single

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

valves, the left more convex than the right, many in ex-
cellent state of preservation. The largest specimen in the
collections of the San Diego Society of Natural History is
a right valve, Cat. No. 2916 (SD), from Reynard Way (the
anterior dorsal portion imperfect), 73.5 mm long, 75 mm
high, convexity 18 mm. Another well preserved right
valve, Cat. No. 4735 (SD), from India Street near Spruce
Street in San Diego, is 65 mm long, 71.6 mm high,
convexity 13 mm.

A fine series comprising most of the specimens of
C. parmeleei studied by us was collected by G. P. Kanakoff
at Locs. 305 and 305A (LAM) near the Mexican boundary.
Individuals of various sizes, from 4 to 79 mm high, were
present. Some attain a height of 32 mm with only a trace
‘of undulation of the shell. Some have three, others as
many as five, constrictions in the shell. These undulations,
where they cross the ribs, lend a nodose appearance to the
ribs.

The ribs are large, convex and consist of folds in the
shell, those of the right valve corresponding to the inter-
spaces of the left. There are four broad ribs on the right
valve and often in addition a narrow, minor one near the
anterior and posterior margins. The ribs on this valve are
separated by narrower interspaces than those on the left.
There are five ribs on the left valve which is more convex
than the right. The ribs and interspaces of both valves are
sculptured with nearly equal, coarse, radial threads. The
anterior ears are much larger than the posterior ones and are
sculptured with 5 to 9 riblets, those on the left posterior
ear are fine and nearly equal in size.

Chlamys parmeleei described by Dall in 1898 was
the first representative of the Swiftopecten group to’ be
described from western North America. West American
species which generally have been considered to be relatives
of C. (S.) parmeleei were originally described in the fol-
lowing chronological order: Pecten etchegoini Anderson
(431), Pecten (Chlamys) hamlini Arnold (432), Pecten
(Chlamys) nutteri Arnold (433), Pecten (Chlamys) wattsi
Arnold (434), Pecten (Chlamys) wattsi var. morani Arnold
(435), and Pecten (Chlamys) kindlei Dall (436). Chlamys
(Swiftopecten) donmilleri MacNeil (437) was described
recently from the Yakataga Formation of probable
middle Miocene age in southeastern Alaska. The illustra-
tions closely resemble some specimens of C. (S.) parmeleei
but the Alaskan species was said to be comparable to the
species described as Pecten (Swiftopecten) otutumiensis
Nomura and Hatai from the Otsutsumi Formation of
middle Miocene age in Japan.

There is considerable variation in the size and
sculpture of the various forms of Swiftopecten of Pliocene
age in California. Arnold (438) later recognized the
identity of the form described as “Pecten (Chlamys)
wattsi var. morani” with Pecten etchegoini. He pointed
out that C. (S.) etchegoini is characterized by a lack of
concentric constrictions whereas such constrictions were
described as common on typical C. (S.) wattsi. We have
examined fragments of the type specimen of C. (S.)
etchegoini which were recovered by F. M. Anderson from
among the ashes caused by fire resulting from the earth-
quake in 1906. These fragments are the remains of a right
valve which is No. 55 in the type series in the department
of Geology, California Academy of Sciences. The largest
fragment is 59 mm high and 42 mm long. It agrees
exactly with the corresponding portion of the original

207

illustration of that species. The specimen shows no con-
centric undulations and it is quite deeply radially grooved.
The latter character, however, may be accentuated due to
erosion and fire.

Nomland (439) illustrated a number of specimens
from the Etchegoin Pliocene of the San Joaquin Valley
and concluded that the species described as Pecten wattsi
and P. nutteri both intergrade with C. etchegoini.

Grant and Gale, 1931, placed C. (S.) parmeleei in
the synonymy of C. (S.) swiftii and C. (S.) etchegoini,
nutteri and kindlei as varieties of C. (S.) swiftii. They
believed that C. (S.) etchegoini was a stunted form bearing
very coarse striations on the ribs.

Stewart in 1941 studied fossil specimens from San
Joaquin Valley and concluded (correctly, we believe) that
west American forms of this group are probably more
closely related to C. (S.) parmeleei than to C. (S.) swiftii
although he recognized their similarity to the Recent
Japanese species. He believed that C. (S.) parmeleei with
prominent undulations is probably the same species as
C. (S.) wattsi Arnold, differing in this character from
C. (S.) etchegoini.

Woodring (in Woodring and Bramlette, 1950), re-
cently inferred from a study of specimens from Pliocene
beds in the Santa Maria district, that there were two recog-
nizable forms in that area, C. (S.) parmeleei in the Cebada
Member of the Careaga Sandstone and C. (S.) parmeleei
elchegoini in the Foxen Mudstone.

Stewart mentioned that the ears of C. (S.) etchegoini,
especially on the left valve, are set off by furrows from the
disk, differing in this respect from C. (S.) swiftii. Wood-
ring (1950) also recognized this difference and mentioned
that the dorsal umbonal portion of large specimens of
C. (S.) parmeleei is more inflated than the corresponding
portion on C. (S.) swiftii. However, these characters vary
in a series of specimens.

Pecten etchegoini Anderson was reported by B. L.
Clark (440) from Pliocene terraces east of San Quintin
Bay, Lower California. Recently Edwin C. Allison (441)
collected a few right valves, the largest, 80 mm in altitude,
from a terrace at the top of the mesa east of San Quintin
Bay. The southernmost occurrence of Swiftopecten
reported from the west coast of North America, is at
Bahia Tortolo (Turtle Bay), Lower California, where
Allison collected a left valve at Loc. B-3019 (UC). The
right valves from east of San Quintin almost lack con-
centric undulations and are deeply grooved. Based upon
this character, these fossils could well be identified with
C. (S.) etchegoini. A portion of a valve similar to these
was collected by Henry Hemphill at Pacific Beach, dif-
fering only in that it is gently undulated. Traces of
microscopic squamation, believed by Dall to be character-
istic of C. (S.) parmeleei, also are present on the valves
from Lower California. Such ornamentation, however,
also is present on specimens of C. (S.) swiftii. The speci-
mens illustrated by Slodkewitsch (442) as representing
C. (S.) etchegoini from strata of Pliocene age in
Kamtschatka, all show concentric undulations and are
probably referable to some other species.

We have not made an intensive study of the mem-
bers of this group described from the San Joaquin Valley,
but C. (S.) parmeleei is the earliest name applied to a
member of this group in North America and any sub-
species or variety of later date must assume a subspecific

208

or varietal status of C. (S.) parmeleei, a fact not recognized
by some of the earlier authors. We consider C. (S.)
parmeleei to be a valid species (including C. wattsi as a
synonym) with C. (S.) etchegoini (including C. morani as
a synonym) as a subspecies and C. (S.) nutteri a separate
species.

The Alaskan form C. (S.) kindlei, said to be character-
ized by its large size and low convexity, resembles C. (S.)
swiftii in general characters and especially in the shape
and size of the posterior ears. We have examined single
valves from Loc. 483 (CAS), from a depth of seventy feet
on a terrace near Nome, Alaska.

A comparison of large specimens of Chlamys (Swifto-
pecten) parmeleei with C. (S.) swiftii from Japan reveals
that on C. (S.) parmeleei and its subspecies the left poster-
ior ear is generally sculptured with finer more nearly
equal riblets. The radial threads on both valves of the
Japanese shell tend to bifurcate toward the ventral margin
whereas those on C. (S.) parmeleei only rarely show this
feature. Furthermore the west American forms do not
reach the size of C. (S.) swiftii which attains a height of at
least 108 mm.

There is variation in the development of undulations
of the valves in a series of C. (S.) swiftii but apparently all
show in some degree undulations or constrictions in the
growth of the shell. Masuda (1959), in discussing the
variation of the shells of C. (S.) swiftii, mentioned that the
valves are less convex and the constrictions less developed
on individuals from northern Asiatic waters. He suggested
that these features may be influenced by the smaller range
in the annual water temperature in northern waters because
greater variation occurs in shells which occur in -more
southern waters where there is greater range in the annual
water temperature.

In addition to the occurrence of Chlamys parmeleei
in the San Diego Formation, it has been reported from the
Yakataga beds in southeastern Alaska; Crescent. City,
northern California; Purisima Formation (443); Jacalitos
Formation and San Joaquin Formation in San Joaquin
Valley; Cebada Member of the Careaga Sandstone, Santa
Maria district; eastern Ventura basin; Simi Valley; in
Elsmere, Holser and Temescal canyons and in the Puente
Hills, southern California. Stanton (Jour. Paleo., Vol. 40,
No. 1, pp. 23, 27, 1966) reported this species from the
Castaic Formation of late Miocene age. We have not seen
specimens from that area.

Chlamys (Swiftopecten) swiftii, a relative of C. (S.)
parmeleei, lives in the waters about Japan, on the Pacific
Ocean side from 38° to 51°north Latitude and on the
Japan Sea side as far south as 35°, at depths of 1 to 143
meters (1 to 78 fathoms).

SUBGENUS LYROPECTEN CONRAD

Lyropecten Conrad, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 14, p. 291, August 1, 1862. Species cited:
“Lyropectin (Pallium) estrellanus, C., Pacific R. R.
Rept., 1855, vi. pl. 3, f. 15.”; “Pallium estrellanum,
in Pacific Railroad Reports, vol. vii. 191,.... I propose
to name it Volaeformis’’; and “‘L. crassicardo.”’ — Dall,
Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, pp. 695,
701, 1898. “Type P. estrellanus Conr.”’ — Arnold,
U. S. G. S., Prof. Paper 47, p. 49, 1906. “Type P.
estrellanus Conrad.” — Woodring, U. S. G. S., Prof.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Paper 190, p. 34, 1938. Type as designated by Dall,
1898.

Lyropectin Conrad (err.), Proc. Acad. Nat. Sci. Philadel-
phia, Vol. 14, p. 291, 1862.

Liropecten Conrad (emend. or err.), Gabb, Geol. Surv.
Calif., Palaeo., Vol. 2, p. 105, 1869.

Not Lyriopecten Hall in A. S. Miller, 1877. Type:
Avicula orbiculata Hall. Middle Devonian.
Type species (designated by Dall, Trans. Wagner

Free Inst. Sci., Vol. 3, Pt. 4, pp. 695, 701, 1898). — “Type
P. estrellanus Conrad.” [Described as Pallium estrellanum
Conrad, Proc. Acad. Nat. Sci. Philadelphia, Vol. 8, No. 6,
p. 313, December, 1856 [apparently issued early in
1857]. “Locality. Estrella valley, Cal.” — Conrad, Pac.
Railroad Expl., Vol. 6, Pt. 2, p. 71, pl. 3, fig. 15, 1856
(1857). “Estrella Valley, Cal.” Lectotype designated by
Woodring (1938, p. 33) as the specimen illustrated by
Arnold (U. S. G. S., Prof. Paper 47, pl. 20, fig. 1, 1906)
which was from “Santa Margarita formation (upper
Miocene), Estrella valley, San Luis Obispo County, Cal.”
This same specimen was designated as neoholotype by
Tucker-Rowland (Mem. Mus. Roy. Hist. Nat. Belgique,
Deuxieme Ser., Fase. 13, p. 4, July 31, 1938).]

Range. — Early Miocene (Vaqueros Formation) to
middle Pliocene.

Description. — Shell large, thick, valves usually
nearly equally inflated, sometimes undulated in the
vicinity of the umbos, sometimes strongly constricted at
various stages of growth; ears nearly equal in size, a byssal
notch present under right anterior ear; ribs large and
undivided; entire shell covered with radial striae and fine
concentric imbrications; hinge with large coarse cardinal
crura or teeth.

Remarks. — Lyropecten was represented during late
Tertiary time in western North America by about a dozen
species and subspecies. Various authors have speculated
on the origin of this group with varying conclusions.
J. P. Smith (444) suggested a Caribbean origin for the
group. Woodring (1938, p. 35) stated that this subgenus
may occur in beds correlated with the Chipola Formation
in Florida of early Miocene age and that it is definitely
represented in the Calvert Formation in Maryland, in beds
of approximately middle Miocene age, but that no species
of Lyropecten are known in the Tertiary strata in the
Caribbean region or in Central America. Olsson (445)
described one species referred to Lyropecten from beds of
late Miocene age in Peru, but we have not seen specimens.
An interesting occurrence is that of a large broad-ribbed
species cited as Pecten (Lyropecten) magnolia Conrad by
Haas (446), but probably referable to the Pecten jeffer-
sonius group, from beds of Miocene age at Carballo, Costa
Rica.

The assignment of large east American late Tertiary
species to Lyropecten has been an accepted practice by
Dall, Gardner, Mansfield, Tucker-Rowland, Woodring,
Grant and Gale, and others. Certainly some of the
species from the east and west American Tertiary beds are
remarkably similar. However, most of the east American
species lack the coarse hinge teeth which are so prominent
on Lyropecten. Dollfus (447) long ago pointed out the
similarity between some of the west American and
Tertiary European species. Later Grant and Gale, and
Clark and Durham (448), mentioned some of the same
“analogous”’ species.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

It is an interesting fact that Conrad who was familiar
with east American species stated concerning Lyropecten,
“This genus is peculiar to the Miocene of the Pacific
slope...”

Most of the European authors while recognizing the
similarity of some of the large European species with
some of the American Tertiary fossils have hesitated to
assign their species to Lyropecten. Roger (1939, p. 246),
who made a careful study of the European Cenozoic
Pectinidae, considered Pecten madisonius Conrad to be a
Chlamys distinct from Lyropecten. North (449) who
studied the supraspecific units of the Pectinidae also
stated that in his opinion the large east American species
are large chlamyds unrelated to Lyropecten. These two
authors, who are familiar with European species, restrict
the usage of Lyropecten solely to west American late
Tertiary species.

The only east American species which we have seen
whose sculpture and hinge bear a resemblance to those of
Lyropecten was described as Pecten (Nodipecten) condy-
lomatus Dall from the early Miocene of Florida. Some
slightly nodose specimens of this species are very similar
to the species described as Pecten (Lyropecten) pretiosus
Hertlein from strata of early Miocene age in Baja Cali-
fornia. A series of specimens of C. condylomatus was
collected by T. F. Stipp from the type San Fernando
Formation (of Dumble, 1915) in Tamaulipas, Mexico.
Some of these, 70 mm high (considerably larger than the
type specimen) and nearly devoid of nodes, closely
resemble some specimens of C. (L.) miguelensis submigue-
lensis Loel and Corey of comparable size from the early
Miocene of California.

The similarity of Pecten magnolia Conrad and P.
Jeffersonianus Conrad to European species of Macro-
chlamis Sacco (450) (Gigantopecten Rovereto, 1898;
Grandipecten Cossmann and Peyrot, 1914), type, Pecten
latissimus Brocchi, has been mentioned by several authors.
It seems possible that they may be of related stock because
there is reason to believe that conditions existed which
were favorable to migration of marine organisms between
the Mediterranean and the western Atlantic. This hypo-
thesis is strengthened by the presence of another Tethyian
subgenus, Amussiopecten, which occurs in mid-Tertiary
beds in the Caribbean (451) region and which is repre-
sented in the west American early Miocene strata by
Pecten vanvlecki Arnold. Amussiopecten also is present
in strata of Miocene age in the East Indies and in beds of
Miocene and of Pliocene age in Japan, but there is no
evidence to indicate that this subgenus reached western
North America by way of the North Pacific. Lyropecten
is not known to occur in that region.

Nodipecten Dall (452) with the type Pecten nodosus
Linnaeus, includes a group of species somewhat similar in
general characters to those of Lyropecten. They have
broad, usually undivided ribs, rather few in number,
ornamented with hollow nodes, and the entire valves are
sculptured with fine or rather coarse radial threads. The
posterior ear is often smaller than the anterior one;
hinge characters similar to those of Lyropecten.

Some species of Pectinidae belonging to quite
different groups bear nodes on their valves, especially on
the ribs where valves are constricted or undulated. Two
such species in the later Tertiary beds of Europe, P.
melii Ugolini and P. sardoa Ugolini, were referred to the

209

“Groupe de Chlamys nodosa” by Roger (453). He placed
(1939, p. 37) Pecten nodosiformis de Serres in the
Chlamys tournali group which he indicated was referable
to ‘“‘Macrochlamys” of Sacco. Eames and Cox (454)
placed that species in the subgenus Gigantopecten under
the genus Pecten. Roger considered Nodipecten to differ
from Gigantopecten [= Macrochlamis Sacco] in the
smaller apical angle, the more unequal ears and better
developed byssal sinus. He stated that only the presence
of nodes creates a similar appearance between the two
groups. The Nodipecten group is known to range from
Miocene to Recent in the Caribbean region and from
Pliocene to Recent in the west American Cenozoic.

Some of the shell characters mentioned by authors
upon which Lyropecten, Macrochlamis, and Nodipecten
have been separated are the difference in the convexity of
the two valves, the presence or lack of a ctenolium
(pectinidial teeth), the apical angle, and presence or
absence of nodes. All these shell characters are variable
and occur in various species assigned to these different
groups.

The type species of Lyropecten is a west American
Miocene species and this group is well developed in that
region from early Miocene to middle Pliocene. Lyro-
pecten, throughout its history, appears to have been
restricted to the eastern Pacific. The latest species, C. (L.)
cerrosensis, occurs in strata of Pliocene age in southern
California and in Lower California. Grant and Gale (455)
assigned Pecten magnificus Sowerby, a Recent tropical
west American species, to Lyropecten, but it is more
properly placed in Nodipecten.

The recent species of Nodipecten are inhabitants of
tropical and subtropical waters. Chlamys (Nodipecten)
subnodosus var. intermedius Conrad, ranges north at least
to Los Angeles Bay in the Gulf of California (perhaps
farther) and to Scammon Lagoon on the west coast of
Lower California (456). Lyropecten also appears to have
been an inhabitant of waters, perhaps subtropical rather
than tropical.

Athlopecten Marwick (457), type Pecten athleta
Zittel, from beds of early Miocene or late Oligocene age
in New Zealand, includes species with large coarse shells
with undivided ribs. There is some resemblance to
Lyropecten but any direct relationship has not been
demonstrated. Pecten athleta bears a resemblance to
Pecten simpsoni Philippi (458), from the middle Tertiary
of Chile, but there is no evidence that either species is
referable to Lyropecten.

Vertipecten Grant and Gale (1931, p. 188), type,
Pecten nevadanus Conrad, has a large thick shell with
irregular, often spiny ribs, and the hinge lacks teeth such
as are present on Lyropecten. They compared Vertipec-
ten to Phialopecten Marwick. We have examined speci-
mens of the type species of Phialopecten, P. triphooki
Zittel, which we received from Dr. C. A. Fleming, and any
postulated relationship with Vertipecten appears purely
speculative.

Sectipecten Marwick with broad ribs, late Miocene
to middle Pliocene in New Zealand, is believed by Boreham
(459) to have been derived from the Mesopeplum group.

Chlamys (Lyropecten) cerrosensis Gabb
Plate 34, Figures 1-4; Plate 36, Figure 7

210

Pecten cerrosensis Gabb, Geol. Surv. Calif., Palaeo., Vol.
2, p. 32, pl. 9, figs. 55, 55a, 1869. — J. P. Smith, Proc.
Calif. Acad. Sci., Ser. 4, Vol. 3, p. 173, 1912. “‘San
Diego-Purisima.” “Pliocene.” — J. P. Smith, Proc.
Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, pp. 150, 151,
1919. “San Diego.” Pliocene. — Hertlein, Stanford
Univ. Bull., Ser. 5, No. 78, pp. 84, 85, 1929. “San
Diego Pliocene.”” — Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 40, 1939. “San Diego hori-
zon.” — Hertlein and Grant, Calif. Jour. Min. Geol.,
Rept. 35 State Mineral., p. 69, 1939. ‘Pacific Beach”
(p. 68), “Pliocene.”

Pecten (Lyropecten) ashleyi Arnold, U. S. G. S., Prof.
Paper 47, p. 122, pl. 47, figs. 1, 1a; pl. 48, fig. 1, 1906.
“The type is from Cerros Island.” Also, “in the low
hills across the mesa three-fourths of a mile northeast
of Pacific Beach, near San Diego.” ‘‘Pliocene.”

Pecten ashleyi [Arnold], J. P. Smith, Calif. State Min.
Bur., Bull. No. 72, p. 38, November, 1916. “‘San Diego
and Lower Fernando formations of the coastal region
of southern California.”

Pecten (Plagioctenium) cerrosensis Gabb, Hertlein, Proc.
Calif. Acad. Sci., Ser. 4, Vol. 14, No. 1, p. 15, pl. 6, fig. 1,
1925. (Illustration of Gabb’s type specimen).

Pecten (Lyropecten) cerrosensis Gabb, E. K. Jordan and
Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No.
14, p. 432, pl. 32, fig. 4 (Cedros Island), 1926. Also,
“San Diego formation of southern California,” Pliocene.
— Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, p. 57, 1944. “Pliocene strata at Pacific
Beach” (p. 56). — Hertlein and Grant, Calif. State Div.
Mines, Bull. No. 170, chapter 2, p. 60, 1954. “San
Diego formation.” Pliocene. — Moore, San Diego Soc.
Nat. Hist., Occas. Paper 15, p. 44, pl. 20, figs. a, b,
1968. Chula Vista, Pliocene.

Pecten (Lyropecten) estrellanus (Conrad) variety cerro-
sensis Gabb, Grant and Gale, Mem. San Diego Soc..Nat.
Hist., Vol. 1, p. 187, pl. 8, figs. 1a, 1b, 2a, 2b; pl. 9,
fig. 2 (specimens illustrated from southern California),
1931. “San Diego (Dall and Stearns in Arnold).”

Lyropecten cerrosensis Gabb, Woodring, U.S. G.S., Prof.
Paper 190, p. 32, pl. 7, figs. 1, 2 (specimens illustrated
from Los Angeles), 1938. Arnold’s record of P.
ashleyi from northeast of Pacific Beach cited (p. 33).
— Woodring, Stewart, and Richards, U. S. G. S., Prof.
Paper 195, table opp. p. 112, p. 113, 1940 (issued
June 7, 1941). ‘Sea cliff at Pacific Beach.” Pliocene.
— Woodring, in Woodring and Bramlette, U.S. G. S.,
Prof. Paper 207, p. 85, pl. 21, fig. 1 (from Santa Maria
district), 1950. P. 104, Pacific Beach; ‘(second bench
back on mesa, 3/4 mile northeast of Pacific Beach)’;
p. 106, “San Diego formation,” “Pliocene.” — Vedder,
U.S. G. S., Prof. Paper 400-B, p. B3827, 1960. ‘San
Diego formation,” also Niguel Formation and others.

Lyropecten (s. s.) estrellatus cerrosensis Gabb, Glibert and
Van de Poel, Mem. Inst. Roy. Sci. Nat. Belgique,
Deuxieme Ser., Fase. 78, p. 24, 1965. Pacific Beach,
San Diego Co., California, Pliocene.

Type specimen. — No. 1091, University of California,

Department of Paleontology.

Type locality. — “‘Cerros Island, off the coast of
Lower California: probably Miocene.”
Range. — Middle Pliocene of southern California

(460) and northwestern Lower California and Cedros

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Island.

Occurrence in San Diego Fm. — C.A.S. 547, 1179,
1413, 1414, 12142, 28159, 28894. L.A.M. 122, 305,
305C.

Original description. — Shell equivalve, subcircular,
broader than long, convex; beaks small; sides sloping con-
cavely above, rounded below; ears small, subequal,
roughened and irregular, sinus very small. Surface marked
by eighteen or twenty flat ribs, with flat or slightly con-
cave interspaces; margins undulated, the ends of the ribs
being deeply emarginated, and the interspaces being pro-
longed into tongue-like processes. (Gabb.)

Remarks. — The type specimen of this species was
discussed and illustrated by the senior author, 1925. The
dimensions of the type are, height, 210 mm, length,
220 mm, convexity (both valves together), 90 mm,
umbonal angle, approximately 110°. The entire shell is
radially striated with fine threads as are other species of
Lyropecten. The interspaces bear four or five striations
or threads of which the central one is stronger than the
others and forms a midrib. As pointed out in earlier dis-
cussions, the specimen referred by Arnold (1906, pl. 49,
figs. 1, la, 1b) to Pecten cerrosensis is referable to other
species and the species which he described under the name
of Pecten (Lyropecten) ashleyi is now believed to be
identical with Gabb’s species.

A large, well preserved specimen in the collections
of the San Diego Society of Natural History, from Tele-
graph Canyon, near Chula Vista, is 193 mm long, 179 mm
high, the convexity (both valves together) 88 mm. Most
of the specimens of C. (L.) cerrosensis in collections from
San Diego which we have examined are single valves and
all except two from near the Mexican boundary are from
or near Pacific Beach. A well preserved right valve, 146 mm
long and 138 mm high, agrees in all details with
specimens from southern California referred to C. (L.)
cerrosensis (or Pecten ashleyi). It has 17 well developed
and radially striated ribs. One of the threads in the center
of the interspaces is coarser than the others and forms a
midrib. Another right valve, from Loc. 1413 (CAS), has
18 radial ribs. Another specimen, the umbonal portion
lacking, but apparently a right valve, has 19 radial ribs
with the midrib in the interspaces only weakly developed.
A right valve, 146 mm long and 138 mm high, from Loe.
305C (LAM), near the Mexican boundary, with 18 radial
ribs and somewhat subdued radial striation, agrees in all
particulars with specimens of C. (L.) cerrosensis from
strata of Pliocene age on Cedros Island.

The general characters of the shell of the present
species closely resemble those of C. (L.) estrellanus (461),
a species of late Miocene age. A midrib is present in the
interspaces between the ribs of C. (L.) cerrosensis as it is
in C. (L.) estrellanus and its subspecies. However, the
midrib is usually decidedly finer than it is on the shells of
of the C. (L.) estrellanus group. Some young specimens
of C. (L.) cerrosensis have a well developed midrib and in
this respect closely resemble some specimens of C. (L.)
estrellanus. Compared to typical C. (L.) estrellanus Con-
rad (see Arnold, plate 20, fig. 1) the valves of C. (L.)
cerrosensis are less inflated, generally larger, more elongated
posteriorly, the midrib in the interspaces is usually
smaller and not split at the margin, there are more
numerous riblets on the ears and often there are more
and coarser radial threads and riblets on the posterior

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

submargin. Chlamys (L.) cerrosensis has more numerous
ribs which are usually more rounded than those on C.
(L.) estrellanus terminus Arnold (462) which has but 15
flat-topped ribs. The valves of C. (L.) cerrosensis are more
convex and the midribs are usually finer than are those of
C. (L.) estrellanus catalinae Arnold (463). Chlamys (L.)
gallegosi E. K. Jordan and Hertlein (464) bears a close
resemblance to C. (L.) cerrosensis but the former species
has flatter, squarer, and much more closely spaced ribs,
the riblet in the interspaces is much coarser and the radial
threads on the shell are generally coarser.

In general outline and sculpture C. cerrosensis
bears a similarity to C. (L.) crassicardo Conrad (465) but
differs in possessing a midrib in the interspaces between
the major ribs, in the usually greater number of ribs, 17
to 19 or 20 in comparison to 14 to 17, also in lacking
constrictions which often are present on the shell of
Conrad’s species.

GENUS HINNITES DEFRANCE

Hinnites Defrance, Dict. Sci. Nat., Vol. 21, p. 169, 1821.
Species cited, Hinnites cortesyi Defrance and Hinnites
dubuissoni Defrance. — Cossmann and Peyrot, Act.
Soe. Linn. de Bordeaux, Vol. 68, p. 141 (Conch. Néog.
de l’Aquitaine, Vol. 2, livr. 2, p. 341), 1914. “G. -T.:
Ostrea crispa Broc.; = Hinnites cortesii Defr. Miocene
et Pliocene.” — Grau, Allan Hancock Pac. Exped., Vol.
23, p. 133, 1959. Type, Ostrea crispa Brocchi, 1814
= Hinnites cortesyi Defrance, 1821.

Hinnita Feérussac and Deshayes, Tabl. Syst. Anim. Moll.,
Tabl. Syst. Géneraux, p. XL, 1822. [No species men-
tioned.] Type designated by Gray (Ann. Philos., New
Ser., Vol. 12, Art. 4, p. 103, August, 1826): Lima
gigantea Gray.

Hinnita Gray, Ann. Philos., Vol. 10, New Ser., p. 104,
August, 1826. Emendation of Hinnites Defrance.
“It [H. gigantea] may be considered as the recent type
of that genus.” On p. 362, November, 1826, “The
name of this genus must be changed to Hinnus.”’

Type species (designated by Gray, Proc. Zool. Soc.
London for 1847, p. 201). — “‘H. Corteysii” [= Hinnites
cortesyi Defrance, Dict. Sci. Nat., Vol. 21, p. 169, Atlas,
pl. 86, figs. 1, la, 1821 = Ostrea crispa Brocchi, Conch.
Subappen., Vol. 2, p. 567, 1814. ‘‘Fossile nel Piacentino,”
Italy. Illustrated by Roger, Mém. Soc. Géol. France,
Nouv. Sér., Vol. 17, Fase. 2-4, Feuilles 7-43, Mém. No.
40 (completion of Mem. de Paléo., No. 26), p. 172, pl. 23,
figs. 11, 12; pl. 25, figs. 1-3 (figs. 1 and 3 “type de H.
cortesyi’); pl. 28, figs 2, 1939 (as Chlamys crispa).
“Pliocene inferieur du Plaisantin”. ]

Range. — Oligocene to Recent.
tide to 110 meters (60 fathoms).

Description. — Shell to an altitude of about 20 or
30 mm resembling Chlamys, then becoming sessile, the
shell becomes irregular, thickened, and the resilial pit
elongated.

Remarks. — The relationships of many members of
this group of mollusks are not known with certainty. It is
believed that some species of Chlamys become attached
and assume a Hinnites form. Fisher (466) studied the
anatomy of Hinnites sinuosus Gmelin (= Pecten pusio
Linnaeus) and stated that no essential differences exist
between the soft parts of that and other species of

Recent from low

211

Hinnites and those of Pecten. This lends credence to the
view of various authors that the genus Hinnites is poly-
phyletic, including species of similar form but genetically
not closely related. This view has been accepted by Dall
(467) and others.

Prohinnites was proposed by Gillet (468) for
Cretaceous species which she considered to bear no
relationship with similar Tertiary forms. Species from
Jurassic strata which Rollier (469) referred to Hinnites are
now placed in different genera.

Despite the obvious differences in the genetic
relationships of the species referred to Hinnites, the shell
characters are so similar that for convenience it seems
best to apply this generic name to the various Cenozoic
species.

One species of Hinnites has been reported to range
from early Miocene to Recent in California. Some authors
consider the Miocene form to be separable as a subspecies.
Finlay and Marwick mentioned that in New Zealand,
Hinnites first appeared in beds of Awamoan, middle
Miocene age.

Hinnites giganteus Gray
Plate 41, Figure 16

Lima gigantea Gray, Ann. Philos., New Ser., Vol. 9, p.
139, 1825. [No locality cited. ]

Not Plagiostoma gigantea J. Sowerby, Miner. Conch., Vol.
1, p. 176, pl. 177 (two figs.), 1814. “This species is
found in great variety in the Bath Lyas or Foetid
Limestone.” England, Jurassic. [Family Limidae. |

Ostrea gigantea [Gray] Wood, Index Test., Suppl., p. 7,
pl. 2, Ostrea, fig. 7, 1828. Habitat unknown.

Hinnita poulsoni Conrad, Jour. Acad. Nat. Sci. Philadel-
phia, Vol. 7, Pt. 1, p. 182, pl. 14, October, 1834. ‘The
habitat is unknown to me” (Conrad.)

Not Pecten poulsoni Morton, Synopsis of the Organic
Remains of the Cretaceous Group of the United States,
p. 59, pl. 19, fig. 2, early in 1834.

Hinnites giganteus Gray, Sowerby, Thes. Conch., Vol. 1,
p. 80, pl. 20, figs. 5-7, November 2, 1842. [No locality
cited. |] — I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 63, pl. 25, figs. 1a, 1b, 1924.
Aleutian Islands to Magdalena Bay, Lower California,
Recent. Also cited from Pliocene and Pleistocene of
California. — Adam, Bull. Inst. Roy. Sci. Nat. Belgique,
Tom 36, No. 20, p. 1, footnote, pl. 2, figs. 3a, 3b,
1960. Balboa, California, Recent.

Pecten rubidus Hinds, varietas (?), Middendorff, Beitrage
zu einer Malacozoologia Rossica, Mem. Sci. Nat. de
l’Acad. Impér. des Sci. de St.-Pétersbourg, Vol. 6, Pt.
3, p. 528 (separate Vol., p. 12) (in part), pl. 13, figs. 4,
5, 6, 1849. “‘die Insel Sitcha (Wosness).”

Not Pecten rubidus Hinds, 1845.

Pecten (Hinnites) giganteus Gray, Kobelt, Syst. Conchyl.-
Cab. von Martini und Chemnitz, Bd. 7, Abt. 2, p. 252,
Taf. 66, figs. 1-3, 1888. West coast of United States
from California to Straits of Juan de Fuca, Recent. —
Arnold, U.S. G.S., Prof. Paper 47, p. 93, pl. 29, figs. 1
(type of H. crassa Conrad), 2 (San Diego, Recent),
1906. P. 94, “Pliocene. Pacific Beach, San Diego
(Arnold).”’

Pecten (Chlamys) multirugosus Gale, Trans. San Diego
Soc. Nat. Hist., Vol. 5, No. 9, p. 92, February 29, 1928.

212

Pecten (Pecten) multirugosus Gale, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 159, pl. 11, figs.
5a, 5b (San Pedro, Calif., Recent), 1931. P. 160,
“Pacific Beach, San Diego (Arnold).”

Hinnites multirugosus Gale, Fitch, State Calif. Dept. Fish
Game, Mar. Fish. Branch, Fish Bull., No. 90, p. 41,
fig. 7, 1953. “Queen Charlotte Islands, British Colum-
bia, to Abreojos Point, Baja, California.” — Grau, Allan
Hancock Pac. Exped., Vol. 23, p. 134, pls. 45-49,
1959. Earlier records cited.

Type specimen. — In British Museum (Natural
History) (A. M. Keen, written comm., February 8, 1967);
of Pecten (Chlamys) multirugosus Gale, No. 5, San Diego
Society of Natural History.

Type locality. — No locality originally cited. Of
Pecten (Chlamys) multirugosus Gale, “The type is a
Recent specimen from San Diego,” California.

Range. — Early Miocene (Fritsche); middle Miocene
(Temblor, “cf.” [Loel and Corey]); late Miocene to
Recent. Recent from the Aleutian Islands, Alaska, to
Magdalena Bay, Lower California, Mexico, in sheltered
waters from high tide to a depth of 55 meters (30
fathoms). In northern waters it lives close to shore and in
shallower water (Fitch).

Occurrence in San Diego Fm. — L.A.M. 305, 309,
Pacific Beach, at letter “‘h” in Pacific “‘Beach” Junior
High School shown on U. S. G. S. topog. map, La Jolla
quad.

Original description of Lima gigantea Gray, 1826. —
“T. oblonga, extus pallide brunnea confertim radiato-
suleata, extus alba, margine cardinali purpurea: Long. 4,
alt. 5 poll.” J

“Trregularly oval, thick, radiately striated, with the
ears small, narrow, hinge thick; colour pale brown, with
reddish radiating streaks, inside white, hinge purple.”
(Gray.) (Ann. Philos., New Ser., Vol. 12, p. 103, 1826.)

“The young of this species is a typical Chlamys up
to the size of 20 or 30 mm. The left valve resembles
closely the left valve of Pecten hastatus Sowerby, or the
young of some specimens of Pecten squamatus Gmelin
from Japan, being sculptured with small radiating ribs,
every fourth or fifth raised above the others and covered
with spines. It is about the shape of P. squamatus but is
slightly more circular than P. hastatus. The right valve
does not have the high paired ribs of P. hastatus, but has
low ribs, flattened on top, nearly all the same size with
only occasionally a slight accentuation of every third. As
soon as the young Chlamys assumes a sessile position,
the growth becomes very irregular, influenced considerably
by the shape of the object to which it is attached, the ribs
become coarser and spinose, and the shell thickens rapidly,
oyster-like, especially the right (the lower) valve which
may in the process develop a greatly elongated resilial
pit.” (For Pecten (Chlamys) multirugosus Gale, 1928.)

Remarks. — A left valve of this species, about 74.3
mm long and 84 mm high and 35.5 mm in convexity, was
collected by G. P. Kanakoff at Loc. 305 (LAM) near the
Mexican boundary. It is more convex than is usual for
this species but otherwise it is similar to Recent
specimens. A right valve, 73 mm long and 76 mm high
was collected by J. F. Arndt near Pacific Beach Junior
High School. A fragment, probably this species, was col-
lected by Kanakoff at Loc. 309 (LAM).

The taxon “Pecten (Chlamys) multirugosus” was

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

proposed by Gale, 1928, to replace Lima gigantea Gray,
1825, because of the earlier Plagiostoma gigantea J.
Sowerby, 1814. Gale considered Plagiostoma to be a sub-
genus of Lima, in which case Gray’s species became a
secondary homonym. Plagiostoma J. Sowerby (1814,
p. 175) was originally described as a genus and it is so used
by many modern authors. Under this usage the
combination Lima gigantea Gray is not a homonym and
the specific name “giganteus”’ is nomenclaturally valid in
combination with the genus Hinnites. We favor retention
of this well known combination of names believing that
this lends stability to the nomenclature of this species.
Adam (1960) recently maintained the validity of this
taxon.

If the name Hinnites giganteus be abandoned the
next available name is “‘Hinnita” poulsoni Conrad. This
name is not a homonym of the earlier Pecten poulsoni
Morton, as believed by Grant and Gale. The type locality
of H. poulsoni Conrad is unknown but nearly all authors
who have considered the taxonomic status of this species
have placed it in the synonymy of H. giganteus.

Hinnites crassa Conrad (470), described from beds
of late Miocene age in California was renamed crassipli-
catus by Gale (471) as a variety of the Recent form
multirugosus. However, the name of Conrad’s species is
not preoccupied by Pecten crassus Risso, 1826, and no
replacement is necessary. Gale believed the Miocene form
to be smaller, usually with the Chlamys stage lasting
longer, with less irregular growth and with fewer more
highly differentiated coarse, rugose radial ridges. The
taxonomic value of the name applied to this form is open
to question. It may be a subspecies of the Recent form
but Arnold (472) considered it to be identical with the
Recent species and we are inclined to that view. Woodring
and Stewart (473) reported ‘“‘Hinnites cf. H. crassa Con-
rad” from the Etchegoin Formation, late Pliocene, in the
San Joaquin Valley. Hinnites benedicti Adegoke (474),
from the Santa Margarita Formation of late Miocene age,
was described from the same region.

Dollfus and Dautzenberg (475) mentioned that a
series of specimens of Hinnites crispa from late Tertiary
beds in Europe reveals variations analogous to those of
H. giganteus.

A paper by Yonge (476) contains the results of a
study of the habits of Recent H. “multirugosus’. He
stated that attachment to the substratum takes place when
the shell is between 2.2 and 4.2 cm high.

This species attains a large size in northern waters.
Eyerdam (477) mentioned a specimen from the San Juan
Islands in Puget Sound which was 222 mm (8 3/4 inches)
long, 168 mm (6 1/2 inches) wide, and near the byssal
plug the valve was 64 mm (2 5/8 inches) thick. The lower
valve weighed 3 pounds and 1 ounce. This species is
gathered for food, only the large adductor muscle is eaten.
A huge specimen 230 mm long, was reported by T.
Meagher from Santa Cruz Island, California. (The
Echo: Western Soc. Malacol., p. 38, 1968).

Henderson (478) pointed out that Bryan’s (479)
record of H. giganteus in Hawaii is referable to a species
of Spondylus. Records of H. giganteus from the Coralline
and the Red Crag in England were referred by Woods (480)
to H. cortesyi Defrance.

:

Oo

————

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

GENUS CYCLOPECTEN VERRILL

Cyclopecten Verrill, Trans. Connecticut Acad. Arts and
Sci., Vol. 10, Pt. 1, p. 70, 1899 [issued June, 1897].
“Types, Pecten pustulosus Verrill; P. imbrifer Loven.”
— Marwick, Trans. New Zealand Inst., Vol. 59, Pt. 4,
p. 909, 1929. “Type: Cyclopecten postulosus Verrill.”
— Grau, Allan Hancock Pac. Exped., Vol. 23, p. 21,
1959. “Type species: Pecten pustulosus Verrill, 1873.”

Cycopecten (err.) de Gregorio, Ann. de Géol. et Paléo.,
Livr., 23, p. 43, 1928.

Cyclochlamys Finlay, Trans. New Zealand Inst., Vol. 57,
p. 452, issued separately, December 23, 1926. “I sup-
ply for it [Pecten transenna Suter, Man. New Zealand
Moll., p. 881, pl. 52, fig. 3, 1913. “Near the snares, in
50 fathoms (type), New Zealand, Recent] the new
generic name Cyclochlamys.’’ — Marwick, Trans.
New Zealand Inst., Vol. 58, Pt. 4, p. 453, 1927, pub-
lished separately February 28, 1928. [Use of Cyclo-
chlamys discussed. |

Not Ciclopecten Seguenza, Boll. Comit. Geol. Ital., Vol.
8, Nos. 9-10, p. 362, 1877. Sole species: Ciclopecten
peloritanus Seguenza, p. 362, 1877. Messina, Pliocene.

Type species (designated by Sykes, Smith, and Crick,
Zool. Rec., Vol. 34, Moll., p. 75, 1898). — “type: C.
pustulosus, Verrill” [= Pecten pustulosus Verrill, Amer.
Jour. Sci., Ser. 3, Vol. 5, p. 14, January, 1873. “Near
St. George’s Bank (s), in 150 fathoms, mud (living); east
of St. George’s (g) in 430 fathoms, sand and gravel (dead,
but fresh valves.)’? off Newfoundland. — Verrill, 1897,
p. 70, fig. 1 (as Cyclopecten pustulosus). — Verrill and
Bush, Proc. U. S. Nat. Mus., Vol. 20, No. 1139, p. 839,
pl. 85, figs. 5,6, 10, 11, 1898 (as Cyclopecten pustulosus) }.

Range. — Late Miocene to Recent. Recent, Atlantic;
eastern Pacific; New Zealand region; in 5 to 2323 meters
(3 to 1270 fathoms).

Original description: Shells thin, rounded, scarcely
oblique, with symmetrical auricles and simple margins. The
two valves are quite unlike in sculpture. The right valve
is a little flattened and upturned at the flexible margin, so
as to fit tightly against the upper valve. The thin lower
valve has, in the typical species, regular, thin, elevated con-
centric lamellae, which aid in the adaptation of the edge to
that of the upper valve; the margin is usually flattened or
bevelled. The upper (left) valve is radially sculptured,
rarely smooth; it usually has radial rows of arched scales,
pustules, or points, and also concentric raised lines; it is
sometimes cancellated. No radial ribs, nor interlocking
points at the margin. Auricles well developed, subequal,
angulated and well-defined at both ends; byssal notch well
defined; few or no pectinidial teeth. Cardinal folds single,
rather feebly developed, often cross-lined. Eyes few.
Byssus small, and of few threads. (Verrill.)

Remarks. — Grau (1959, p. 22) mentioned that
“Some species do not have the ventral margin of the right
valve flexed, and one, Cyclopecten acutus sp. nov., does
not have concentric lamellae or ridges on that valve. Most
species are translucent but a few are opaque”. He included
twelve west American species in Cyclopecten.

The shells of species of Cyclopecten are prismatic in
structure. Some of the species with flexed ventral margin
of the right valve resemble some species of Propeamussium
(481) but differ in lacking internal radial rays.

Chlamydella Iredale (482) differs from Cyclopecten

213

in the elongated (anterior-posterior) form and in that the
right valve is sculptured with fine radial riblets separated
by raised scales, the left with fine concentric raised
threads.

Barnard (483) described Cyclopecten incubans from
South Africa which contained juvenile forms. He pointed
out that this apparently is the first reported occurrence of
incubation in the Pectinidae.

Cyclopecten pernomus Hertlein
Plate 33, Figures 7, 11

Pecten (Cyclopecten) rotundus Dall, Bull. Mus. Comp.
Zool. Harvard Coll., Vol. 43, No. 6, p. 404. “U.S.S.
‘Albatross’, station 2799, in Panama Bay, in 29 1/2
fathoms; also at station 2784, in 194 fathoms, mud,
bottom temperature 51.9° F. U.S. N. Mus. 110, 708.”

Not Pecten rotundus von Hagenow, 1842, p. 554. Chalk
on Rigen Island in Baltic Sea, Cretaceous.

Pecten (Cyclopecten) pernomus Hertlein, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 21, No. 25, p. 320, pl. 18, figs.
11-13, September 26, 1935. Dall’s localities cited, also
others. A new name for Pecten (Cyclopecten) rotundus
Dall, 1908, not Pecten rotundus von Hagenow, 1842.

Cyclopecten pernomus Hertlein, Grau, Allan Hancock Pac.
Exped., Vol. 23, p. 32, pl. 11, September, 25, 1959.
Numerous localities cited from western Lower Cali-
fornia to Ecuador. — Keen, Sea Shells of Tropical West
America (Stanford Univ. Press: Stanford, California),
p. 72, fig. 135, 1958. Cedros Island, Lower California
to Panama.

Amusium (Cyclopecten) pernomus Hertlein, Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 168, pl. 21, fig. 6, 1961.
Cedros Island, Lower California, to Panama, Recent.

Type specimen. — No. 110, 708, United States Na-
tional Museum.

Type locality [of Pecten (Cyclopecten) rotundus
Dall]. — “U. S. S. ‘Albatross’, station 2799, in Panama
Bay in 29 1/2 fathoms.”

Range. — Middle Pliocene to Recent. Recent from
Cedros Island, west coast of Lower California, Mexico, and
Angel de la Guardia Island in the Gulf of California, to
La Libertad, Ecuador. Also Guadalupe Island and Gala-
pagos Islands (Grau). In 2 to 1,720 meters (1 to 940
fathoms) (484). “Usually found in mud bottoms, oc-
casionally sandy mud or sand; sometimes associated with
eel grass or weed” (Grau).

Occurrence in San Diego Fm. — L.A.M. 305A, 305C.

Original description (of Pecten (Cyclopecten) rotun-
dus Dall). — Shell very small, thin, white, suborbicular,
with subequal ears, both valves nearly equally convex; right
valve polished, minutely regularly concentrically striated,
which sculpture is barely visible under a hand lens;
posterior ear smooth, anterior finely radially threaded,
with a narrow but clean-cut byssal sulcus and fasciole; left
valve finely sharply radially striated, the anterior ear
finely reticulated, the posterior apparently nearly smooth;
hinge line short, straight; interior smooth, a pair of small
auricular crura present; the hinge line with a minute central
pit and two relatively large transversely sharply striated,
elongate areas representing a permanent provinculum.
Height and length, 3; hinge line 2.5; diameter, 1.0 mm.
A single valve from near the Straits of Magellan, apparently

214

the same species, measures 7 mm in height. (Dall.)

Supplementary description. — The right valve is
slightly smaller than the left. Its anterior auricle has con-
centric as well as radial striae; its posterior auricle is not
“smooth”, having 7 to 11 fairly prominent radial threads
and finer concentric threads. The posterior auricle of the
left valve is not “nearly smooth,” having both fine radial
and finer concentric threads. On about half of the
hundreds of left valves examined there were gray-brown,
yellow-brown, red-brown or deep brown areas, irregular
and varying in size; the right valves were all white. Speci-
mens measuring 10 mm in altitude were taken at Hancock
station BS 2130, Pond Island, northern Gulf of California,
in 62-85 fathoms; the largest specimens previously re-
corded were 7 mm in altitude. (Grau.)

Remarks. — Ten single valves varying in degree of
preservation, are present in the collection of Los Angeles
County Museum from Locs. 305A and 305C (LAM) from
near the Mexican boundary. The largest is about 5.5 mm
long. Some of them retain traces of the brownish color
markings on the ventral portion of the shell.

These specimens agree in all shell characters with
Recent specimens of Cyclopecten pernomus dredged in
tropical west American waters. Gilbert Grau agrees with
this assignment. This is the first record of the occurrence
of this species in the fossil state.

Cyclopecten pernomus lacks the distinct posterior
flexure which is present on the right valve of C. cocosensis
Dall (485). The auricles of C. pernomus are much less
acutely pointed than those of C. acutus Grau (486) from
West Colombia and the left valve is sculptured with con-
centric ridges rather than with fine radial threads.

Grau (1959, p. 33) pointed out that the single valve
from the Strait of Magellan which Dall believed to be
probably referable to ‘‘Pecten (Cyclopecten) rotundus”
[= C. pernomus] is not conclusive evidence that this
species lives in those southern waters.

SUPERFAMILY LIMACEA RAFINESQUE
FAMILY LIMIDAE RAFINESQUE (487)

Shell monomyarian or with a single adductor scar,
obliquely subpectiniform with small, narrow ears and
median beaks, equivalved, inequilateral, the shorter side
being posterior, usually white, externally sculptured with
fine or coarse, generally scabrous radial riblets. Lateral
margins generally thickened, the anterior one with an open
gap. Hinge line straight, edentulous, or with obscure
denticulations on the side, the cardinal area high, sub-
triangular with a central resilial pit under the beak in each
valve. A thin brown deciduous periostracum is often
present. (Olsson, Mollusks of the Tropical Eastern Pacific
(Paleo. Res. Inst.: Ithaca New York), p. 169, 1961.)
Late Paleozoic (Carboniferous) to Recent.

Remarks. — The triangular ligamental pit in this
family is external, rather than internal, and the position
of the adductor impression is higher and more posteriorly
situated than it is in the Pectinidae. A byssus may be
present or lacking, but if present it extends through a
slight gape in the valves. Some members lacking a byssus
are active swimmers.

Early members of this family, so abundant and large
in the Mesozoic Era, were discussed by Cox (488).

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

GENUS LIMA BRUGUIERE

Lima Bruguiere, Encyl. Méth. (Tabl. Vers.), pl. 206, 1797.
[ Name and figure only. ] — Cuvier, Tabl. Elém. Hist. Nat.
Anim., p. 421, AN 6 [1797 (489).] Sole species, Lima
alba Cuvier with Ostrea lima Linnaeus in synonymy.
— Gardner, U.S.G.S., Prof. Paper 142-A, p. 52, 1926.
“Type: Ostrea lima Linnaeus.” — Vokes, Tulane
Studies in Geol., Vol. 1, No. 2, p. 75, 1963. “Type
species by subsequent tautonomy (Lamarck, 1801)
Ostrea lima Linnaeus, 1758 = Lima squamosa Lamarck,
1801, Recent, apparently world wide in warmer waters.”

Type species (by tautonomy, Cuvier, 1797). — Ostrea
lima Linnaeus (in the synonymy of Lima alba Cuvier).
[Ostrea lima Linnaeus, Syst. Nat., ed. 10, p. 699, 1758.
“Habitat in O. meridionali.”” Ref. to ‘““Argenv. Conch. t.
27, f. E.” This was illustrated without specific name by
Bruguiere, 1797, pl. 206, fig. 4 and it was described under
the name of Lima squamosa by Lamarck, 1801, and by
Deshayes, Encyl. Méth., Vol. 3, p. 345, 1832. Also
illustrated by Sowerby, Reeve’s Conch. Icon., Vol. 18,
Lima, sp. 10, pl. 2, fig. 10, 1872 (as Lima squamosa
Lamarck). For a discussion of Ostrea lima Linnaeus see
Dodge, Bull. Amer. Mus. Nat. Hist., Vol. 100, Art. 1, pp.
186-187, 1952; also Vokes, 1963, pp. 75-76. |

Range. — Triassic to Recent. Shallow to deep water.

Description. — Shell equivalve, inequilateral, bicon-
vex, oblique, auriculate, edentulous, usually gaping an-
teriorly; the anterior region larger than the posterior, in
which the umbones are situated. Posterior auricle larger
than or equal to the anterior. Hinge-line straight, short.
Area triangular, with a central ligament pit. Adductor im-
pression large. Two small pedal impressions. (Arkell,
W. J., Palaeongraphical Society London, Vol. 83, Corall.
Lamell., Pt. 3, p. 128, 1931.)

Remarks. — Most members of this group are
ornamented with radial ribs which may be nearly smooth
or scaly. The exterior of others may be nearly smooth.

Lima is represented by abundant species in beds of
Mesozoic age but their number declined during the
Cenozoic. Only three species are known to occur in beds
of Pliocene age in California, and these are rarely found.
The genus is here recorded from the San Diego Formation
for the first time. Species of Lima are widely distributed
in the seas at the present time; eleven species have been
reported living in west American waters.

Species of this genus can swim by clapping the valves
together and expelling currents of water from the mantle
cavity. Some species spin “nests” in which they are
enclosed.

SUBGENUS LIMARIA LINK

Limaria Link, Beschreib. Nat. -Sammlung Univ. Rostock,
Abt. 3, p. 157, May 17, 1807. Species cited include
“L. inflata.”” — Winekworth, Proc. Malacol. Soc.
London, Vol. 19, Pt. 3, p. 116, November, 1930. “I
here choose inflata as type.” — Hertlein and Strong,
Zoologica, Vol. 31, Pt. 2, No. 5, p. 66, 1946. Type as
designated by Winckworth.

Mantellum Bolten, Morch, Cat. Conch. Comtes de Yoldi,
Fase. 2, p. 57, 1853.

Not Mantellum Roding in Bolton, Mus. Bolt., p. 160,
1798.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Winckworthia Glibert and Van De Poel, Mém. Inst. Roy.
Sci. Belgique, Deuxieme Sér., Fase. 78, p. 49, 1965.
“Type. —(Ice désigné), Ostrea tuberculata Olivi, 1972.”
[Zool. Adriatica, p. 120. “Abita nei fondi arenosi
misti del mar dirimpetto alla spiaggia occidentale.”
Ref. to Gualtieri, Test., Tab. 88, fig. FF. ]

Type species (by subsequent designation, Winck-
worth, 1930). — Limaria inflata Link founded on Chem-
nitz (490), Conchyl. -Cab. Bd. 7, pl. 68, fig. 649, lit. a
[cited as ““641.a” by Link], 1784. “Kuste von Guinea und
an den Stranden der westindischen Zuckerinsuln.” [=
Ostrea tuberculata Olivi, 1792.]

Range. — Early Cretaceous (Neocomian) to Recent.

Description. — Shell of medium size (larger ones
about 40 mm high), moderately thin, oblique, posterior
margin bulging; submargins not impressed; usually some-
what inflated, gaping anteriorly and often more so
posteriorly; sculptured with rather fine ribs of variable
size, often scaly; ligament pit broadly triangular; a small
but well developed pit beneath the posterior ear and
usually a weaker one under the anterior ear; foot without
byssus or retractor.

Remarks. — Limaria is here recorded from the San
Diego Formation for the first time.

Species of this subgenus, at the present time, live in
temperate and tropical waters. One species lives in
Californian waters.

Promantellum Iredale (491) differs but little from
Limaria except that the valves of the type species may
be more widely gaping.

Submantellum Olsson and Harbison (492), with the
type Lima orbignyi Lamy, differs from Limaria in the
greater inflation of the valves, which gape but slightly
anteriorly and lack any gape posteriorly.

A paper by Studnitz (493) deals with the anatomy
of two of the small Atlantic species of Limaria.

Lima (Limaria) orcutti n. sp.
Plate 35, Figure 11; Plate 36, Figures 2-5;
Plate 57, Figure 10

Description. — Right valve, shell obliquely elliptical
in outline, inequilateral, moderately convex; greatest
length (anterior-posterior) about halfway between beak
and ventral margin, gaping along the posterior dorsal mar-
gin; hinge short, oblique, the posterior ear pointed,
a shallow sinus immediately below it; the anterior margin
nearly straight above, but below it is gently rounded
into the ventral margin, the outline of the posterior
and ventral margin forms a braod arc; anterior umbonal
slope rather steep, the posterior slope rather gentle;
the valves are sculptured with about 35 to 40 fine,
radial riblets, some vaguely paired, all separated by wider
interspaces, ribs and interspaces widest on medial portion
of the valve, the whole crossed by fine imbricating lines
of growth; hinge elongately triangular, with a broad
shallow, triangular ligamental pit, a triangular pit under
the posterior ear, a shallow depression under the anterior
one; the interior smooth, in some places the external
ribbing is visible. Dimensions of holotype: Height (beak
to ventral margin) 43 mm, length approximately 35.5 mm
(posterior side imperfect), convexity (left valve) approxi-
mately 9.6 mm.

Type specimen. — Holotype and paratype in Los

215

Angeles County Museum.

Type locality. — Loc. 305C (LAM), exposure at base
of hill, 100 feet west and 440 feet south of the northeast
corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base
and Meridian (see U. S. G. S., topog. map, San Ysidro
quad., rev. 1953.)

Range. — Middle Pliocene (San Diego formation).

Occurrence in San Diego Fm. — L.A.M. 305, 305C,
319.

Remarks. — This species is represented in the
present collection by five valves, fairly well preserved, and
by a number of fragments. The largest of the valves, a
right valve, is selected as holotype.

This new species bears a general resemblance to
Lima hemphilli Hertlein and Strong (494) which now
lives in adjacent waters but the new species has fewer,
coarser, more widely spaced ribs, the greatest length of the
valves (anterior-posterior) is at a point about midway be-
tween the beak and the ventral margin rather than above
the middle, the hinge plate is relatively broader and the
posterior ear is much less acutely pointed.

The general features of the hinge are more like that
of Lima orbignyi Lamy (495), but the shell of the new
species is much more elongated, less inflated and the valves
gape posteriorly.

The general outline of this new species is somewhat
like that of Lima auaua Dall, Bartsch, and Rehder (496),
from Hawaii, but the character of the ribbing appears
to be quite different.

SUPERFAMILY OSTREACEA RAFINESQUE (497)
FAMILY OSTREIDAE RAFINESQUE (498)

Shell porcelaneous, inequivalve, dimyarian when
young, monomyarian when adult, with posterior ad-
ductor impression in each valve; edentulous (or obscurely
so); attached by cementation by the umbo or by the
whole outer surface of the left valve to rocks, roots of
trees or other objects; valves often much distorted due to
fixation; valves usually close fitting, the left one usually
larger and deeper, the right one often flat; sculpture alike
on the two valves or different. Marine or brackish water.
[Adapted from Dall in Eastman’s edit. of Zittel’s text
book of Paleo., Vol. 1, pp. 451-452, 1913, and Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York) p. 171, 1961.] Triassic to
Recent.

Remarks. — Newell (499) recently suggested that
the pseudomonotids may have been ancestral forms giving
rise to oysters. He mentioned that “true oysters are dis-
tinguished by loss of the foot and byssus during the
prodissoconch stage, cementation by the left valve, and
possession of a calcite shell. The last two characteristics
apparently were not acquired before early or middle
triassic time ... .”

An excellent summation of the various supraspecific
group names in this family and their type species was
published by Stenzel (500), and Baughman (501) published
an annotated bibliography of oysters.

GENUS OSTREA LINNAEUS

Ostrea Linnaeus, Syst. Nat. ed. 10, p. 696, 1758. Many
species cited including Ostrea edulis Linnaeus. — Dall,

216

Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p. 671,
1898. ‘Type Ostrea edulis Linné.” — Lamy, Jour. de
Conchyl., Vol. 73, No. 1, p. 12, 1929. “Type O.
edulis L.”

Ostreum DaCosta, Hist. Nat. Test. Brit., p. 154, 1778.
Type designated by Winckworth (Proc. Malacol. Soc.
London, Vol. 17, Pts. 2 and 3, p. 106, December
1926): ‘‘T. vulgare, da C. (here chosen) = Ostrea, L.”

Ostracites Gmelin, Linn. Syst. Nat., ed. 13, p. 404,
1793. Type designated by Stenzel (Jour. Paleo., Vol.
21, No. 2, p. 178, March, 1947): “GT: Ostrea edulis
Linneé”.

Ostraea G. B. Sowerby, Jr., Conch. Man., ed. 1, p. 75, and
on table, 1839. Emendation of Ostrea Linnaeus.
Suppressed as a synonym of Ostrea Linnaeus, see
opinion 148, Internatl. Comm. Zool. Nomencl.

Monoeciostrea Orton, Nature (London), Vol. 121, p. 321,
March 3, 1928. Type designated by Iredale (Great
Barrier Reef Exped., 1928-29. Sci. Repts., Vol. 5,
No. 6, Moll., Pt. 1, p. 394, 1939): “Logotype:
Ostrea edulis Linné.”

Type species (by Linnaean tautonymy; also desig-
nated by Schmidt, Versuch. Conch. Samml., pp. 69, 177,
1818). — Ostrea edulis Linnaeus. Ostrea with the type
species, Ostrea edulis Linnaeus, was placed on the official
list of generic names in Zoology by the Internat!. Comm.
Zool. Nomencl. (Opinion 94, published October 8, 1926).
[Ostrea edulis Linnaeus, Syst. Nat., ed. 10, p. 699, 1758.
“Habitat in Oceano Europaeo.” References include
Gaultieri, Test., pl. 102, fig. B; Klein, Ostr., pl. 8, fig. 21;
Bonaninni, Recr., t. 70. Also illustrated by Sowerby in
Reeve’s Conch. Icon., Vol. 18, Ostraea, sp. 8, pl. 5, figs.
8a-f, 1870. See also discussion of this species by Dodge
(Bull. Amer. Mus. Nat. Hist., Vol. 100, Art. 1, p. 192,
1952). The chalky deposits in the shell of this species
were discussed by Korringa (Proc. Calif. Acad. Sci., Ser. 4,
Vol. 27, No. 5, pp. 133-158, 2 figs. in text, 1951). ]

Range. — Triassic to Recent. Recent, world-wide
in temperate and tropical marine and brackish waters,
from the intertidal zone to about 91 meters (50 fathoms)
but usually abundant in less than 18 meters (10 fathoms).
Ostrea cochlear is reported (502) from 2174 meters
(1,189 fathoms).

Description. — Shell ovate, elongate or irregular in
outline, attached by the left valve; upper valve flat or con-
cave or sometimes convex, often unsculptured; lower
valve convex, often plicated or foliaceous or with a
prominent beak, dimyarian in juvenile state, monomyarian
in adult (the anterior adductor lacking); ligamental cavity
triangular or elongated; hinge toothless (except in very
early stage of growth); margins smooth or with denticles;
structure subnacreous, laminated, with prismatic cellular
substance between the margins of the laminae. (Adapted
from Tryon, Struct. and Syst. Conch., Vol. 3, 1884, p.
297, and Dall in Eastman’s edit. of Zittel’s Text-book of
Paleo., Vol. 1, p. 450, 1913.)

Remarks. — The species of Ostrea have been the
subject of a vast amount of literature. Much of this is a
result of their economic importance because many of the
species are highly valued as food. Many of the fossil forms
are valuable aids as indicators of the geologic age of the
strata in which they occur.

The majority of oysters including all the large, thick
shelled forms live in shallow water or on bottoms exposed

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

between tides. The shape and sculpture of the shells of
various species varies greatly because of the influence of
the character of the bottom, the currents, or the chemical
content of the waters in which they live.

A number of species of Ostrea have been described
from strata of Tertiary age in California (503). One of
these Ostrea titan Conrad, a huge species of Miocene age,
has been reported to attain a length of 457 mm (18
inches). One species and two or possibly three varieties,
live in the waters between the Bering Sea and San Diego,
California (504). Along with these in some bays is
a Japanese species Ostrea gigas Thunberg (or the variety
laperousei Schrenck) and Ostrea virginica Gmelin (505)
and others, introduced for commercial purposes. About a
dozen species and subspecies of this genus live in tropical
and subtropical waters of the western Americas (506).
The Recent species in the Museum of Natural History in
Paris were discussed by Lamy (507), those of Japan by
Hirase (508) and those of Australia by Thomson (509).

Five species occur in the San Diego Formation.

Key to Species of Ostrea

A. Valves smooth . erici

B. Valves with radial plications
a. Dorsal margins with denticles
b. Valves falcate in outline megodon

bb. Valves roundly trigonal to ovate
in outline

c. Upper valve flat fitting into
plicate margins of the lower one .
cc. Upper valve slightly arched,
margins interlocking with the
lower one

vespertina

. angelica

aa. Dorsal margins lacking denticles . . veatchii
Ostrea angelica Rochebrune
Plate 38, Figures 2, 3

Ostrea cumingiana Dunker of west American authors. —
Durham, Geol. Soc. Amer., Mem. 43, Pt. 2, p. 58, pl. 5,
fig. 6, 1950. Late Pliocene to Recent in the Gulf of
California region.

Not Ostrea cumingiana Dunker, Zeitschr. f. Malakozool.,
Jahrg. 3, p. 48, March, 1846. ‘Patria ignota.” —
Philippi, Abbild. u. Beschreib. Neuer oder wenig
gekannte Conchyl., Bd. 2, Heft 3, Ostrea, p. 81, Taf. 1,
figs. 1, 2, 3, 4, October, 1846. ‘Patria ignota.” —
Hirase, Jap. Jour. Zool., Vol. 4, No. 2, p. 213, fig. 1,
1932 [as Ostrea (Lopha) cumingiana]. Omami,
Oshima, Japan. — Adam and Leloup, Mem. Mus. Roy.
Hist. Nat. Belgique, Hors Sér., Rés. Sci. Voy. Ind.
Orient. Neerland, Vol. 2, Fase. 20, p. 66, 1939.
Manokwari.

Ostrea angelica Rochebrune, Bull. Mus. d’Hist. Nat.
(Paris), Vol. 1, p. 241, 1895. “Baie de Los Angeles,”
east coast of Lower California. — Contreras An. Inst.
Biol. (Mexico), Vol. 3, No. 3, p. 207, figs. 18 and 19,
1932. ‘Bahia de Los Angeles, Golfo de California.” —

Eo

?
|

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Keen, Sea shells of Tropical West America (Stanford
Univ. Press), p. 65, fig. 117, 1958. “The Gulf of
California to Ecuador.’”’” — Emerson and Hertlein,
Trans. San Diego Soc. Nat. Hist., Vol. 13, No. 17,
p. 353, figs. 3a-c, 1964. Isla Angel de la Guardia, ?Plio-
cene; Isla Carmen, Pliocene.

Type specimen. — Muséum Nationale d’Histoire
Naturelle de Paris.

Type locality. — ‘“‘Hab. Baie de Los Angeles, ou elle
forme des bancs d’une étendue considérable.”’ [East coast
of Lower California. ]

Range. — Middle Pliocene to Recent. Recent from
San Ignacio Lagoon to San Felipe, Lower California, and
south to Mazatlan, Mexico. To Ecuador (Keen). [Not
reported from the Panamic region by Olsson, 1961.] At
the mouths of estuaries and bays, on stones, etc., where
there is a current, but sheltered from breakers.

Occurrence in San Diego Fm. — C.A.S. 28888. S.D.
409. U.C.L.A. 303.

Original description. — O. Testa aggregata, plerumque
irregulariter ovoideo rotundata, apice plus minusve
attenuata, ad marginem undulato dentata; umbonis arcuatis,
ligamento obliquo; valvis inaequalibus; valva inferiore
subprofunda, intense adherens, circulariter radiatim
costata; costis crassis subangulosis; valva superiore plana,
centraliter corrugata, circulariter radiatim costata, costis
irregularibus, obtusis plicatis, plicis imbricatis latis; extus
albo viridula, intus albo nitida virescente; impressione
subcentrali albo, trapezoideo; marginibus lateralibus
prope umbonibus, minutissime denticulatis.

Long. 0,080 mm. — Latit. 0,055 mm. — Crass.
0,023 mm. (Rochebrune.)

Remarks. — The fossils here referred to Ostrea
angelica agree closely in all observable shell characters with
Recent specimens of that species from the Gulf of Cali-
fornia.

Recent specimens of O. angelica are usually oblong
or rounded and the shell is rather thick. The lower valve
is decidedly convex, the upper one only gently so. Both
valves are sharply plicated over the distal half or one third
of their surfaces which interlock along the margin, but the
plications usually do not extend much beyond the pallial
line on the interior of the valves. Exteriorly the color is
light green with purplish radial streaks, the interior olive-
green or shining whitish-green, occasionally entirely white.
Denticles or transverse vermiculations are present on the
margins from the ligamental pit usually to about a
third the distance to the ventral margin. The muscle im-
pression is posterior to the center, trapezoidal in shape,
white. Large specimens in the collections of the California
Academy of Sciences from Mejia Island, Gulf of California,
are 122 mm high (beak to base), 95 mm long, convexity
(both valves together), 41 mm.

Small specimens of O. angelica differ from O. lurida
laticaudata Carpenter (510) in the greater thickness of
the shell, the more convex upper valve which is more
deeply plicated and along the margin interlocks down-
ward with the lower valve rather than turning upward
along the margin and fitting into the scalloped margin of
the lower valve. Adult shells of O. angelica attain a much
greater size and thickness than forms of O. lurida.

These same shell characters serve to separate O.
angelica from O. palmula Carpenter, with which it occurs
in the Gulf of California. The interior margins of Recent

217

O. palmula are blue or purplish blue, rather than tinted
with green. Furthermore denticles often are present for a
greater distance distally along the margins of O. palmula
than on O. angelica.

The valves of O. angelica are generally larger, thicker,
and more deeply plicated than those of O. vespertina.
The plications on the exterior of the valves usually are
present only on the distal half or third of the valves of
O. angelica. On the lower valve these plicae extend from
the margin to the broad unplicated area of attachment.
The corresponding area of attachment on O. vespertina is
usually much smaller. Furthermore the upper valve of
O. angelica is more convex, the plications interlock
downward along the margin, whereas on O. vespertina the
upper valve is almost flat and fits into the scalloped edges
of the lower valve similar to that of O. lurida laticaudata
and O. palmula.

Ostrea caboblancoensis Weisbord (511) described
from strata of Pliocene age in Venezuela, bears a
resemblance to O. angelica.

Ostrea angelica is reported here for the first time
from the San Diego Formation. It is known to occur on
terraces near San Antonio del Mar (512), in beds of
Pliocene age, at Cedros Island and at Bahia Tortolo
(Turtle Bay), Lower California, and in strata of Pliocene
and Pleistocene age in the Gulf of California region (513).

Ostrea erici Hertlein
Plate 38, Figures 4, 6, 8, 9

Ostrea erici Hertlein, Jour. Paleo., Vol. 3, No. 3, p. 295,
September, 1929. A new name for Ostrea tayloriana
Gabb, E. K. Jordan and Hertlein, Proc. Calif. Acad.
Sci., 4th Ser., Vol. 15, No. 14, p. 428, pl. 33, fig. 3,
1926. [Not Ostrea tayloriana Gabb, Geol. Surv. Calif.,
Palaeo., Vol. 2, p. 34, pl. 12, figs. 60, 60a, 1866.
“Miocene, from San Marcos Pass, near Santa Barbara”’,
California. (Eocene.) ] — Hertlein and Grant, Mem. San
Diego Soc. Nat. Hist., Vol. 2, p. 59, 1944. India Street
at corner of Upas Street, San Diego. — Woodring, in
Woodring and Bramlette, U. S. G. S., Prof. Paper No.
222, pp. 65, 85, 104, 106, pl. 8, figs. 17, 18; pl. 9,
figs. 1, 3, 4, 1950. [All figures represent specimens
from Pliocene of Santa Maria district.] P. 104, India
and Upas streets; p. 106, San Diego Formation,
Pliocene. — Hertlein and Grant, Calif. State Div. Min.,
Bull. 170, Chap. 2, p. 60, 1954. San Diego Formation,
Pliocene. — Vedder, U. S. G. S., Prof. Paper 400-B,
p. B327, 1960. San Diego Formation. Also Niguel
Formation and others.

Type specimen. — No. 2094, California Academy of
Sciences, Department of Geology, Type Collection.

Type locality. — From “mouth of big arroyo
northwest of Elephant Mesa, Scammon Lagoon Quadrangle,
Lower California. Pliocene’’.

Range. — Middle Pliocene, southern California, and
Lower California.

Occurrence in San Diego Fm. — C.A.S. 1135, 1183,
28892, 28893, 33334. L.A.M. 107, 124, 180, 309. S.D.
415, 2912, 2951. U.C.L.A. 309.

Description. — Shell moderately large, elongately to
roundly trigonal, sometimes slightly expanded poster-
iorly; lower valve arched, right (upper) valve flat, both
valves composed of rather coarse overlapping shell

218

laminae; ligamental pit on both valves elongately trigonal,
rather small for the size of the shell; hinge plate at end of
pit rounded and very slightly overhanging a shallow cavity;
a small flat-topped indentation, corresponding to the lines
of growth, occurs on each side of the ligamental pit;
interior of shell smooth, large adductor impression
rounded to semi-lunar, situated on the posterior side
dorsally a little over one half the distance from the ventral
margin to the beak; body cavity often bounded on each
side by smooth, steep walls beyond which the shell tapers
to a thin edge; margins smooth, no denticles present.
Dimensions of the holotype: maximum length (beak to
base), 100.5 mm, transverse length, 78 mm, convexity
(both valves together), 36 mm.

Remarks. — This interesting oyster was collected
chiefly in the strata exposed on and near Reynard Way
and at the end of Arroyo Drive in San Diego. A represen-
tative specimen from Loc. 28893 (CAS), is 108 mm high
(beak to base), transverse length, 94 mm, convexity (both
valves together), 46.9 mm. It was first recorded from beds
in northern Lower California by E. K. Jordan and Hertlein.
Since then it has been recorded at a number of localities
in beds presumably of about the same age as that of the
San Diego Formation, namely, at Fourth and Broadway
streets in Los Angeles (514), in theSisquoc Formation and
in the Cebada Member of the Careaga Formation in the
Santa Maria district, in the Niguel Formation near San
Juan Capistrano, in beds of middle Pliocene age on Car-
men Island (515) in the Gulf of California, and question-
ably in the Gloria Formation in the Santa Rosalia area
(516), east coast of Lower California. A portion of an
upper valve from beds of Pliocene age on Maria Madre
Island, Mexico, may be referable to the present species.

Ostrea erici is not similar to any Recent west Amer-
ican species.

Ostrea vespertina Conrad
Plate 39, Figures 1-3, 5-9

Ostrea vespertina Conrad, Jour. Acad. Nat. Sci. Philadel-
phia, 2nd Ser., Vol. 2, Pt. 4, p. 300, 1854. [February,
1854, in table of contents. Also stated to have been
presented at Academy meeting March 7, 1854 (see An
Index to Sci. contents of the Journal and Proceedings
of the Acad. Nat. Sci. Philadelphia, 1812-1912, p. IX,
1913).] — Conrad, House Doe. 129, Projected Vol. 3,
33rd Congress, 1st Session, pp. 7, 15, July, 1855. P. 7,
“Colorado desert,” p. 15, “Locality. — Carrizo Creek,
Miocene.” Reprint by Dall, U. S. G. S., Prof. Paper
59, p. 168, 1909. — Conrad, in Blake, U. S. Pac.
Railroad Expl., Vol. 5, Pt. 2, p. 325, pl. 5, figs. 36, 37,
38, 1857. “Carrizo creek, Colorado desert. Miocene.”
— Conrad, in Emory, Rept. U. S. Boundary Surv., Vol.
1 Pie e25 sp. 60; pl. 17; figs. La-d, 1857. “Carrizo
Creek, and near San Diego, California (Miocene). —
Heilprin, U. S. G. S., 4th Ann. Rept., p. 315, pl. 71,
figs. 2, 3, 4, 1884. ‘Carrizo Creek, Colorado Desert.”
(Conrad). Pliocene (Gabb). — Schuchert, Dall, et al.,
U.S. Nat. Mus., Bull. 53, Pt. 1, p. 475, 1905. “‘Miocene.
Carriso Creek, and near San Diego, California.”” —
Arnold and Anderson, U. S. G. S., Bull. 322, pp. 59,
148, pl. 23, fig. 10, 1907. “One mile north of
Schumann.” “Fernando (Pliocene).’’ — Arnold, U. S.
G. S., Bull. 396, p. 77, pl. 24, figs. 4,5, 1909. “Upper

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Etchegoin formation; locality 4715.” “Upper Miocene.”
[Pliocene.] P. 79, ‘‘Pacific Beach, Russ School, San
Diego well, San Diego County (Henry Hemphill; W. H.
Dall; Homer Hamlin; Delos and Ralph Arnold, and
others). “San Diego formation, lower Pliocene.” —
Arnold and Anderson, U. S. G. S., Bull. 398, pp. 129,
138, pl. 46, figs. 4, 5, 1910. [Same figures as in pre-
ceding reference.] — Hanna, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 14, No. 18, p. 468, pl. 26, figs. 1, 2, 3,
1926. Coyote Mountain, Imperial Co., California, Plio-
cene. Also ‘“‘San Diego,” Pliocene. — E. K. Jordan and
Hertlein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No.
14, p. 428, 1926. “San Diego,” Pliocene. — Hertlein,
Stanford Univ. Bull., Ser. 5, No. 78, pp. 84, 85, 1929.
“San Diego Pliocene.’ — Woodring, U. S. G. S., Prof.
Paper 190, p. 42, pl. 8, figs. 1, 2, 3, 4, 8, 9; pl. 9, fig. 5,
1938. [Lectotype, figs. 3and 8. Figs. 1, 2, 4, 9, from
Barrett’s oil well, south side of Imperial Co., California,
Pliocene. Plate 9 fig. 5, from Third Street tunnel, Los
Angeles, California.]_ P. 44, localities near San Diego
“Pliocene San Diego formation.” — Woodring, Stewart,
and Richards, U. S. G. S., Prof. Paper 195, table opp. p.
112, p. 113, 1941. ‘San Diego.” ‘Pacific Beach.” —
Hertlein and Grant, Mem. San Diego Soc. Nat. Hist.,
Vol. 2, Pt. 1, p. 59, 1944. “Near the intersection
of Thirty-fourth and Tomkins Streets,” San Diego,
Pliocene. — Hertlein and Grant, Calif. State Div. Mines,
Bull. 70, Chapt. 2, p. 60, 1954. San Diego Formation,
Pliocene. — Emerson and Hertlein, Trans. San Diego
Soc. Nat. Hist., Vol. 13, No. 17, p. 3538, fig. 3 d-h
(p. 356), 1964. Coyote Mountain, Imperial Co.,
California, Pliocene.

Type specimen. — Lectotype No. 4502, Academy
of Natural Sciences of Philadelphia.

Type locality. — “Locality. Near San Diego, Cali-
fornia. Dr. LeConte.’”’ ‘“‘Miocene Species?”

Range. — Late Miocene (Nomland; Stanton); Plio-
cene.

Occurrence in San Diego Fm. — C.A.S. 1136, 1176,
1402, 1413, 28882, 28887, 28889, 28890, 28892, 34221,
36599. L.A.M. 107, 122, 124, 180, 302, 305, 305A,
309, 323, 208. S.D. 20, 37, 80, 331, 365, 408, 413,
446, 1142. U.C.L.A. 294, 296, 302, 310, 1382, 1383,
1385, 2420.

Original description. — Ovato-subfalcate, lower valve
plicated or ribbed; hinge long and wide, sharp and some-
what pointed; ligament cavity wide, profound, minutely
wrinkled; margins abrupt, cavity not very deep; muscular
impressions large, impressed; upper valve flat, irregular;
pallial impression crenulated throughout its whole extent,
profoundly crenulated on the upper half of the shell.
From beak to base 1 7/8; transversely 1 1/2. (Conrad.)

This species has a remarkable resemblance, ex-
ternally, to a variety of O. borealis. The upper margin of
the muscular impression is generally of a sigmoidal out-
line. (Conrad.)

Remarks. — Specimens of an oyster found in
Pliocene strata at several localities in and near San Diego
agree in all particulars with Conrad’s original description
of Ostrea vespertina. The lower valve is usually convex,
bearing 5 to 10 plications, and the upper valve is flattish
and fits down into the fluting around the margin. The
margin below the ligamental area bears denticulations
which sometimes occur along the margin for half the

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

length of the valve. Some of these specimens agree with
illustrations of the upper valve selected by Woodring for
the lectotype of this species.

Woodring, 1938, gave an extensive discussion of the
problems concerned with the identification of Ostrea
vespertina. Conrad originally gave the locality as “near
San Diego,” but some authorities consider it doubtful that
Conrad’s specimens came from this locality. Three years
later (1857) he gave another description and illustrations
and cited the species from “Carrizo Creek. Miocene.” In
another report the same year he described and illustrated
specimens and gave the locality “Carrizo Creek, and near
San Diego, California. (Miocene).”

Through the courtesy of Dr. Horace G. Richards, we
were able to study the type lot of nine specimens of this
species which are preserved in the Academy of Natural
Sciences of Philadelphia. As mentioned by Woodring, the
label does not bear the locality nor the name of the col-
lector but the preservation is such as to indicate to him
that they came from “evidently Carrizo Creek.” This
appears a reasonable conclusion. He illustrated only upper
(right) valves but four lower (left) valves also are in the
type lot. The lectotype selected by Woodring is a nearly
flat upper valve, 37.7 mm long (slightly incomplete) and
48.6 mm high.

We also have studied a series of specimens from
Loc. 33277A (CAS), collected by G D. Hanna from an
oyster reef in Painted Gorge on the north side of
Coyote Mountain, Imperial Co., California. These speci-
mens agree exactly with Conrad’s illustrations of 1857
(plate 5, figs. 36-38) and possess similar denticulations
along the upper margins. This feature was not mentioned
by Woodring as being present on the lectotype but such
denticulations are visible in shell layers along the anterior
edge of the dorsal margin of that specimen and they are
present on others in the type lot. Denticles are present on
some valves from San Diego only 2 mm high (beak to
base). The muscle impressions are often somewhat ex-
tended upward along the posterior end. Some of these
specimens are virtually indistinguishable from Recent
specimens of Ostrea palmula Carpenter (517), described
one year later from the Gulf of California. Perhaps the
average Recent specimen has the upper margins a little
more fluted and the excavation under the beak of the
lower (left) valve a little deeper but these features are
variable in a large series. In any case, the specific name
vespertina is the earlier of the two.

The chief difference between specimens from the
San Diego Formation and those from the Carrizo Creek
region appears to be size. Some specimens from San Diego
are 75 mm high and 55 mm long (more circular forms may
be 65 mm long). We have used the name Ostrea vespertina
for our specimens because many left valves agree in all
conchological characters with the lectotype which bears
the earliest name proposed for a fluted oyster with a
flattish upper valve and denticulate margins from strata
of Pliocene age in southern California.

Woodring (1938, p. 44; 1940, p. 92), pointed out
_that some weakly plicated or nearly smooth valves of
_ O. vespertina sequens Arnold (518), described from beds
of late Pliocene age in San Joaquin Valley, California, are
not separable from elongate specimens of O. lurida
Carpenter (519) which, he suggested, may be a modern
) representative of that subspecies. The group of species

i
)

219

including O. vespertina and its subspecies O. v. sequens,
O. palmula, O. conchaphila Carpenter (520) and O. lurida
and its forms (521), have many shell characters in common
and it appears reasonable to conclude that they represent
a closely related group of species.

The large oyster from Imperial Co., California,
named Ostrea heermanni by Conrad (522) has an ovate,
flattish, very thick shell. The body cavity is fairly deep
on the anterior side and the exterior flutings are reflected
interiorly along the margins of rather thin valves, but not
on thick valves. The growth lines are decidedly looped
upward on each side of the ligamental area, distinctly
different from those of O. vespertina which are but
slightly or not at all looped upward.

Some authors have considered a close relationship
to exist between O. vespertina, O. haitensis Sowerby, O.
heermanni Conrad, and O. wiedeyi Hertlein. The latter
three species bear a greater resemblance to O. veatchii
Gabb and their similarities will be discussed in connection
with that species. Studies of the type lot of O. vespertina
and other specimens from the type locality, also the
selection of a lectotype by Woodring, have furnished a
basis for separating this species from typical O. veatchii
with which it has been united by some authors.

Arnold (1909, p. 78) pointed out that “‘O. vespertina
is smaller, relatively narrower, and usually more falcate in
outline and carries plaits more regular in size and generally
fewer in number than O. haitensis.’’ Both Dall and Arnold
pointed out that the west coast species closely resembles
O. sculpturata Conrad (523) from the late Miocene and
Pliocene of eastern United States. The illustrations of that
species from Florida by Mansfield (524) are remarkably
similar to some specimens of O. vespertina from the San
Diego Formation. A subspecies, Ostrea vespertina vene-
zuelana Weisbord (525), described from strata of Pliocene
age in Venezuela, is very similar to some forms of O.
vespertina from southern California.

The record of Ostrea vespertina cited as occurring
in the Miocene of Ceylon by Deraniyagala (526) obviously
is referable to O. virleti or one of that group. The species
cited by Masson and Alencaster Ibarra (527) as “‘Ostrea
sp. ef. O. vespertina Conrad”’ from Miocene beds of San
Andres Tuxtela in the State of Vera Cruz, Mexico, is
referable to one of the east American species. The record
of “Ostrea cfr. vespertina Conr.” cited by Khomenko
(528) from beds of Miocene age in Kamtschatka, evidently
is referable to some other species. Conrad’s species was
not cited by Slodkewitsch, 1938, in his comprehensive
work on the late Tertiary fauna of that region.

Ostrea vespertina has been cited as occurring in
beds of late Miocene age in central California and in the
San Joaquin valley (529), but we have not seen specimens
certainly referable to this species from strata of that age.

This species has been recorded as occurring in strata
of Pliocene age as far north as the San Benito and San Juan
Bautista quadrangles in California. It has been reported
from beds of that age in southern California, Lower
California, and south to Maria Madre Island, Mexico.

Ostrea veatchii Gabb
Plate 39, Figure 4;
Plate 40, Figures 1, 4, 5, 6

O[strea]. veatchii Gabb, Geol. Surv. Calif., Palaeo., Vol.

220

2, p. 34, pl. 11, fig. 59, 1866. — Dall, Proc. U.S. Nat.
Mus., Vol. 1, p. 11, “San Diego,” p. 29, “about ten
miles northward from San Diego,”’ 1878. — Heilprin, in
White, U. S. G. S., Fourth Ann. Rept., p. 316, pl. 72,
fig. 1, 1884. (Copy of Gabb’s illustration). — [?]
Arnold, Mem. Calif. Acad. Sci., Vol. 3, p. 63, 1903 (as
“Ostrea veatchi2”’). “Pacific Beach” and “Russ School’,
San Diego, Pliocene. — Arnold, U. S. G. S., Prof.
Paper 47, p. 28, 1906. “San Diego Formation”.—
Arnold, in Eldridge and Arnold, U. S. G. S., Bull. 309,
p. 250, pl. 39, fig. 1, 1907. “Lower Pliocene, San
Diego.”

Ostrea vespertina Conrad, E. K. Jordan and Hertlein,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, pp. 417,
428-429, 1926 (in part). “San Diego’, also Cedros
Island, Bahia Tortolo (Turtle Bay), and near Elephant
Mesa, Lower California, Pliocene.

Not Ostrea vespertina Conrad, 1874.

Ostrea haitensis Sowerby subsp. vespertina Conrad, Stew-
art, Acad. Nat. Sci. Philadelphia, Spec. Publ. No. 3, p.
128, pl. 14, fig. 4, 1930. “The holotype of O. veatchii
is figured.”

Type specimen. — No. 4502, Academy of Natural
Sciences of Philadelphia.

Type locality. — ‘“‘Cerros Island, associated with
Pecten Veatchii, P. cerrosensis, and the following species
[O. cerrosensis Gabb]. Dr. J. A. Veatch.”

Range. — Middle Pliocene, from San Diego, Cali-
fornia, to Bahia Tortolo (Turtle Bay) and Cedros Island,
Lower California.

Occurrence in San Diego Fm. — S.D. 6307.

Original description. — Shell large, subequivalve,
varying from nearly equilateral to very oblique, the
obliquity being always to the left side. Surface marked by
ten or a dozen large, angular, radiating ribs, some of which
arise at or near the beaks, the others branching from the
first, or interpolated between them; the interspaces are
angular, and the ribs are marked by more or less squamose
plates, and occasionally these plates assume almost the
character of spines; internally the ribs show only towards
the margins. Hinge short, very broad and shallow; no
crenulations or denticulations near the margin. Muscular
scar large, suboval to subquadrate. (Gabb.)

Remarks. — Two valves from Pacific Beach agree
with the form described as Ostrea veatchii Gabb. The
largest of these is 125 mm long. The valves are deeply and
sharply fluted and some of the flutings develop extensions
into spines. Specimens such as these have been considered
by several authors to be variants of O. vespertina.

Through the courtesy of Dr. Horace G. Richards,
Academy of Natural Sciences of Philadelphia, we have
been able to examine the type lot of Ostrea veatchii. The
type is a comparatively thin (about 4 mm) lower valve,
75 mm high and 68 mm long, the upper anterior margin
incomplete. The exterior is sculptured with about 10
angular, radiating ribs which at intervals develop into
spines. Interiorly there is no recessed area under the
hinge, the muscle impression is fairly large and rounded,
and as mentioned by Gabb, there are no denticles along
the margin of the valve. An upper valve, about the same
size, gently convex, sculptured similar to the type, is in the
type lot.

The gently arched upper valve, more numerous,
spinose ribs which deeply interlock along the ventral

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

margin and the smooth margins totally lacking denticles
are shell characters quite different from those of O.
vespertina from its type locality. Some of the tubular
spines on a specimen from Cedros Island in the col-
lections of the Los Angeles County Museum (A. 6573.54-2)
are 28 mm long (see pl. 40, fig. 5). The shell of typical
specimens is lamellar with irregular open spaces between
the lamellae. Dr. Hendryk B. Stenzel mentioned to us
that this kind of shell structure is similar to that of some
members of the Ostrea hyotis group. We restrict the usage
of the name O. veatchii to specimens agreeing in general
shell characters with the type specimen. Among Recent
west American oysters, the presence or lack of denticles
along the margin below the hinge is a rather constant
character.

Examination of about 50 specimens from Pliocene
strata on Cedros Island, the type locality of O. veatchii,
and of additional specimens from Bahia Tortolo (Turtle
Bay), Lower California, reveals considerable variation.
Some of these agree exactly with Gabb’s type and lack
denticles on the margin. Others, usually smaller, more
trigonal or faleate forms have very fine denticulation only
along the upper portion of the margin, others have denticu-
lation similar to that on O. vespertina. Also occurring at
Cedros Island are specimens agreeing in every way with O.
angelica. The variation in this series from Cedros Island is
such as might lead one to question whether perhaps some
of these are hybrids between O. veatchii and O. angelica.
For the present we believe it desirable to retain O. veatchii
as a separate taxon at least until the relationships of west
American oysters are better known.

Exteriorly some specimens of O. angelica bear a
close resemblance to O. veatchii and that probably ex-
plains Dall’s (530) citation of the latter as occurring
Recent in the Gulf of California. The shell of O. angelica
is usually thicker, the flutings usually do not extend to the
dorsal third of the valves and do not develop into spines,
interiorly the margins below the ligamental pit are finely
denticulate, and the muscular impression is semicircular
in outline.

A large rounded, thick (40 mm at thickest), flattish
valve illustrated by Gabb (1869, pl. 17, figs. 21, 21a;
Heilprin, 1884, pl. 72, fig. 1) under the name of Ostrea
veatchii, which accompanied the type lot of O. veatchii,
is 123 mm long, 131 mm high, maximum thickness about
42 mm. It closely resembles specimens of O. heermanni.
In the text (pp. 60, 61) following the caption to the
figures of this specimen, Gabb mentioned the occurrence
of thick, flat oysters from the east coast of Lower Cali-
fornia. It seems probable that the valve discussed here
came from that region.

Ostrea wiedeyi Hertlein (531) described from early
Miocene strata on Santa Rosa Island, California, bears
a strong resemblance exteriorly to O. veatchii. The shell
of this Miocene species is much thicker and on some
specimens the growth lines loop upward to some extent
on each side of the ligamental area. Another feature
noticed on the interior of these fossils is the presence of
a depression just below the hinge on the posterior side of
the body cavity.

Loel and Corey (532) considered O. wiedeyi to be
identical with O. loeli Hertlein which they placed as a
variety of O. vespertina. The thick shell, shape of body
cavity, and muscle impression, as well as the shape of the

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

hinge line of O. wiedeyi bear a greater resemblance to O.
heermanni than to typical O. vespertina. Ostrea wiedeyi
bears a close resemblance to Ostrea haitensis Sowerby as
illustrated by Maury (533) from the late Miocene of
Trinidad but the west coast species differs in lacking the
transverse vermiculate threads on the margin below the
hinge.

Ostrea veatchii, at times, has been placed in the
synonymy of O. haitensis Sowerby (534), a species oc-
curring in strata of Miocene age in the Caribbean region.
The west American shell represents a similar but distinct
species with a thinner shell and without denticles or
transverse threads on the margin. The Ostrea haitensis
group includes species such as O. gatunensis Brown and
Pilsbry described from beds of Miocene age in the Panama
Canal Zone and perhaps in a general way includes west
American fossil forms such as O. wiedeyi Hertlein, O.
loeli Hertlein and O. howelli Wiedey. Ostrea haitensis
closely resembles O. virleti Deshayes, a large plicated
oyster which occurs in strata of late Tertiary age in
the Mediterranean and Indian Ocean regions. The
distribution of O. virleti was discussed by Davies (535)
and its relationships by Cox (536).

We are uncertain what species is represented by
Dall’s record (537) of Ostrea veatchii from late Tertiary
beds on Atka Island and Unga Island, Alaska. The same
can be said for the records of O. veatchii from Miocene
strata in western Washington cited by Weaver (538).
Ostrea fisheri Dall (539), a large round form, living in
the Gulf of California and known from Pliocene to Recent
in that region, is believed to be closely related to O.
hyotis Linneaus, an Indo-Pacific species and to O. thomasi
McLean which lives in Floridan waters.

SUBGENUS AGEROSTREA VIALOV

Agerostrea Vialov, Acad. Sci. URSS, Compt. Rend.
(Doklady), Nouv. Ser., Vol. 4 (13), No. 1 (105), p. 20,
1936. — Stenzel, Jour. Paleo., Vol. 21, No. 2, p. 168,
1947.

Type species (by original designation). — “‘type:

A. ungulata Schloth.” [= Ostracites ungulatus Schlottheim

Taschenbuch f. Mineralogie herausgegeben von C. C.

Leonhard, Jahrg. 7, Abt. 1, p. 112, 1813. Ref. to “Knorr

P. Il. T. D. Vii. F. 3. und 6. Petersberg.”’ Illustrated by

Coquand, Monographie du genre Ostrea. Terrain Cretace

(Marseille), p. 58, Atlas, pl. 31, figs. 4-15, 1869. — Carter,

Palaeontology, Vol. 11, Pt. 3, p. 463, pl. 85, figs. 2,3 ;

pl. 86, fig. 6; pl. 87, fig. 8, 1968. ]

Range. — Late Cretaceous to Recent.

Original description. — Coquille longue, étroite,
incurvée, avec une surface médiane lisse. (Vialov.)

Remarks. — Many supraspecific group names have
been proposed in the Ostreidae. Some authors have
placed Ostrea megodon in the subgenus Lopha Roding in

Bolten (540) which has as type O. crista-galli Linnaeus, a

Recent species. Recently, Dr. H. B. Stenzel suggested

(pers. comm.) that O. megodon could be placed in

Agerostrea Vialov which was based upon a species origi-

nally described from beds of Maestrichtian, late Cretaceous

age. We have not seen specimens of the type species of

Agerostrea but some of the illustrations referred to O.

ungulata by Coquand (see especially his pl. 31, figs. 6, 7, 8)

closely resemble O. megodon in general shape and shell

221

characters.

Many species, especially of Jurassic and Cretaceous
age, have been assigned to Lopha, as have others in the
Cenozoic. Recent species of that genus occur in shallow
tropical and subtropical marine waters.

There is no agreement among authors as to which,
if any, Mesozoic species should be assigned to Lopha.
Gillet (541), following Douvillé, considered typical
“Alectryonia” Fischer de Waldheim (type, Ostrea crista-
galli Linnaeus) [= Lopha] to predominate from late
Cretaceous to Recent.

Beginning in middle Jurassic a group of oysters
developed which were predominant during late Jurassic
and early and middle Cretaceous. These are arcuate in
outline with long, narrow beaks and numerous extremely
angular plicated margins and they are less equilateral in
form than Lopha. The genus Arctostrea Perivinquiére
(542) was proposed for these with the type species
Ostrea carinata Lamarck. Some authors have placed
Arctostrea in the synonymy of Lopha but these taxa
represent quite distinct supraspecific units.

The name Rastellum Schroter, 1782, was discussed
and rejected by Stenzel (1947, pp. 181-182). The history
of Rastellum as a genus name is rather involved but usage
of it by authors subsequent to Schroter is much later than
the name Lopha.

Ostrea (Agerostrea) megodon Hanley
Plate 38, Figures 1, 5, 7

Ostrea megodon Hanley, Proc. Zool. Soc. London, Pt. 13,
for 1845, p. 106 (issued February, 1846). — Sowerby,
Conch. Icon., Vol. 18, Ostraea, species 24, pl. 12, figs.
24a, 24b, 1871. “Peru.” — E. K. Jordan and Hertlein,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 427,
pl. 28, fig. 1, 1926. ‘‘Pliocene beds at Bernstein’s
abalone camp on southeast side of Cedros Island.
Pliocene.” Also other localities.

Ostraea gallus Valenciennes, Zool. Voy. Venus, pl. 21, figs.
1, a-d, 1846. [No description. }

Ostrea cerrosensis Gabb, Geol. Surv. Calif., Palaeo., Vol.
2, p. 35, pl. 11, fig. 61, 1866. “with the preceding
species”. [That is, Ostrea veatchii Gabb from “‘Cerros
Island, associated with Pecten Veatchii; P. cerrosensis,
and the following species.” |

Ostrea megadon Hanley subsp. cerrosensis Gabb, Stewart,
Acad. Nat. Sci. Philadelphia, Spec. Publ. No. 3, p. 130,
pl. 14, fig. 1, 1930. [One of Gabb’s type specimens
illustrated as a lectotype. ]

Ostrea (Lopha) megodon Hanley, Keen, Sea Shells of
Tropical West America (Stanford Univ. Press: Stan-
ford, California), p. 66, fig. 123 (Scammon’s Lagoon),
1958. Scammon’s Lagoon, Lower California, to
Paita, Peru, Recent.

Ostrea (Alectryonia) megodon Hanley, Olsson, Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 172, pl. 23, figs. 3, 3a (“‘Bay-
ovar, Peru’), 1961. Gulf of California to northern
Peru, Recent. — Olsson, Neogene Mollusks from North-
western Ecuador (Paleo. Res. Inst.: Ithaca, New York),
p. 39, pl. 1, figs. 1-1b (Punta Gorda, Ecuador, Plio-
cene), 1c (Quebrada Mellisa, Burica Peninsula, Panama,
Pliocene), 1964.

Type specimen: British Museum (Natural History).

222

Type locality. — ‘Hab.
Cuming.”

Range. — Pliocene to Recent. Recent from Scam-
mon’s Lagoon, west coast of Lower California, Mexico, to
San Felipe and Puerto Penasco in the Gulf of California
and south to Paita, Peru, in 15 meters (8 fathoms) to 112
meters (61 fathoms).

Occurrence in San Diego Fm.—S.D. 6307. U.C.L.A.
2420.

Original description. — Ost. Testa falcata, glabra,
solida, subaequivalvi, pallidé livido-purpurascente, mar-
gines versus plicata; plicis anticis 5 aut 6, maximis,
subangulatis; posticis minimis, angulatis, paucis, sub-
obsoletis; margine valde plicato, intusque magis minusve
scabro; natibus incurvatis; superficie interna albo-vires-
cente, nunquam margaritacea; cicatrice satis magna, reni-
formi. Long. 5 poll. (Hanley.)

Remarks. — Two small specimens of Ostrea megodon
are present in the collections from Pacific Beach. One
from Loc. 6307 (SD) is 42.3 mm long and 29.3 mm wide.
The other specimen, from Loc. 2420 (UCLA), is 39.6 mm
long (beak to base), 21 mm wide, convexity (not including
flutings), 12 mm. These specimens, except in size, agree
in all observable shell characters with Recent specimens of
O. megodon from tropical west American waters, in shape,
muscle impressions, and denticulated dorsal margins.
There is variation in the development of denticulation on
Recent specimens of this species. On some, denticles
occur along the margin for about one half the distance
from the beak to the vental margin, on others these are
well developed below the beak but soon become weaker
ventrally. ,

The measurement of the type specimen of Ostrea
megodon given as “‘5 poll” is equivalent to approximately
126.6 mm. The largest Recent specimen in the Academy’s
collection is a left valve collected by Don Frizzell at
Brazo Ramon estuary, south of Sechura, Peru. It is
107 mm long (beak to base). A Recent specimen from
Bahia Tortolo (Turtle Bay), Lower California, is 78 mm
long (beak to base), 40 mm wide, the convexity (not in-
cluding flutings), 19.5 mm. Galtsoff (543) mentioned
that specimens of this species in Panama attain a length of
15-16 cm, but this appears to be an exceptional size.
Olsson (1961; 1964) has discussed Recent and fossil
specimens of this species from northwestern South
America and Panama.

The name Ostrea gallus Valenciennes, 1846, ac-
companied illustrations of a fluted oyster but was not
accompanied by a description. The illustrations obviously
appear to be referable to O. megodon and this interpre-
tation has been accepted by most authors.

Gabb in 1869 described Ostrea cerrosensis from
strata of Pliocene age on Cedros Island, Lower Cali-
fornia. Stewart later discussed and illustrated one of
Gabb’s type specimens and placed it as a subspecies of O.
megodon. The reason for retaining O. cerrosensis as a
subspecies was based upon the difference in size between
the type specimens of O. megodon and O. cerrosensis.
The illustration given by Gabb, said to be natural size, is
approximately 59 mm long. The dimensions of the
specimen illustrated by Stewart as lectotype of O. mego-
don cerrosensis were given as 53 mm long, 66 mm high,
convexity (not including flutings), 15 mm.

A specimen of Ostrea megodon collected by E. K.

Peru (Cuming). Mus.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Jordan from strata of Pliocene age on Cedros Island is
79 mm long (beak to base) and a larger specimen collected
from the same general area by Mrs. Joyce Roderick is
101 mm long (beak to base). Specimens from beds of Plio-
cene age in Ventura County, Loc. 90 (CAS), are 99 mm
long. All these specimens, although not so large as the
type specimen of O. megodon, agree with that species in
all observable shell characters. We therefore place O.
cerrosensis Gabb in the synonymy of Hanley’s species, as
did Dall.

Woodring, Bramlette, and Kew (544), assigned the
subspecific name Ostrea megodon cerrosensis to an oyster
with broad shallow plications from late Pleistocene beds
in the Palos Verdes Hills in Los Angeles Co. The degree of
width and depth of fluting varies in a series of Recent
specimens from tropical west American waters and there-
fore we are inclined to consider as referable to O. mego-
don those fossil specimens which differ from Recent ones
only in the degree of fluting. Large Recent specimens
have 5 to 6 rounded well developed flutings along the
anterior margin. The exterior is colored greenish and
purple, and the interior whitish and green.

Ostrea megodon has been recorded from beds of
late Tertiary age in the Caribbean region but most of
those records are now referred to closely related forms
which have been described as separate species.

Ostrea paramegodon Woodring (545) from the
Bowden beds of late Miocene age in Jamaica, was described
as smaller, less curved and with shallower folds than O.
megodon. Woodring stated that except for size, the
fossil from the Gurabo Formation, Miocene, in the
Dominican Republic, illustrated by Maury (546), greatly
resembles the west American O. megodon.

The species cited by Olsson (547) under the name
of O. megodon from Miocene strata in Costa Rica, was
later placed in the synonymy of O. messor Maury (548)
which was described from strata of late Miocene age in
Trinidad. Maury also described O. messor var. caimita and
O. messor var. tabiquita. A subspecies from the Miocene
of Columbia was described by Weisbord in 1929 as O.
messor colombiensis. We have examined specimens from
Miocene beds in Columbia identified by Anderson (549)
as O. “‘megadon”. These are smaller and less curved in
outline than most Recent shells of this species which we
have observed.

Undoubtedly a number of forms from strata of late
Tertiary age in the Caribbean region and the west American
O. megodon form a closely related group. The fossil
forms vary somewhat in size, curvature and magnitude of
flutings. Just how many of these should retain separate
specific or subspecific designation is open to question.
Weisbord (550) recently discussed several members of this
group.

SUPERFAMILY ANOMIACEA RAFINESQUE (551)
FAMILY ANOMIIDAE RAFINESQUE (552)

Shell large or small, generally irregular and distorted,
attached by close contact to various objects by means of
a calcified byssal plug passing through a round hole or
foramen in the umbone of the right valve, remaining
attached throughout life or only in the early stages.
Valves rounded or subcircular, variously inflated, but
generally more or less irregular because of fixation, nac-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

reous, and often with a platy or micaceous texture, thin
or heavy. Hinge edentulous but sometimes provided with
large, divergent resilial processes or crura simulating hinge
teeth. Ligament internal, attached to resilial processes
along the hinge margin or to deep scars. Interior of the
left valve has two or three rounded or elongated scars
which represent the attachment impressions of the byssal
and retractor muscles. (Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 175, 1961). Jurassic to Recent.

The members of the Anomiidae live between tides
or in comparatively shallow water attached to other shells
or to rocks.

This family is represented in the San Diego Forma-
tion by two genera.

Key to Genera of Anomiidae

A. Upper valve with one large and one small

muscle impression . . Pododesmus
B. Upper valve with one large and two small
muscle impressions. Anomia

GENUS ANOMIA LINNAEUS

Anomia Linnaeus, Syst. Nat., ed. 10, p. 700, 1758.
Numerous species cited including Anomia ephippium.
— Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4,
pp. 774, 781, April, 1898. “Type A. ephippium
Linne.”” — Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 240, 1931. Type (as indicated by
Children, 1823): Anomia ephippium Linnaeus.

Type species (designated by Schmidt, Versuch der
Conchylien-Sammlung, pp. 71, 177, 1818). — “Typ.
Anomia ephippium” [Linnaeus]. [Anomia ephippium
Linnaeus, Syst. Nat., ed. 10, p. 701, 1758. ‘‘Habitat in
M. Mediterraneo & America.” Illustrated by Chemnitz,
Syst. Conchyl. Cab., Bd. 8, p. 81, pl. 76, figs. 692, 693,
1785. Cited from ‘‘Mittellandischen See”, also ““Ostund
Westindischen Meeren.” See discussion of this species
by Dodge, Bull. Amer. Mus. Nat. Hist., Vol. 100, Art. 1,
pp. 198-199, 1952. “The form to which Linnaeus gave
the name ephippium is that common on the west coast
of France.’’]

Range. — Jurassic to Recent. Recent cosmopolitan,
except in Arctic and Antarctic. From the intertidal zone
to 3001 meters (1094 fathoms). Usually in intertidal or
shallow water.

Description. — Shell subrounded or irregular in
outline, rather thin, attached with a calcified byssal plug
which passes through a sinus in the right valve; left (upper)
valve with one large and two smaller muscle impressions;
hinge edentulous.

Remarks. — Five species of Anomia have been
reported from Cenozoic strata of California, one of which
occurs in the San Diego Formation. One Recent species
lives in west American waters between San Pedro, Cali-
fornia, and Paita, Peru. In tropical and subtropical waters
it is accompanied by one or possibly two species of
Anomia, whose systematic status is doubtful.

The exterior of valves of Anomia may be smooth or

223

with radial ribs which on the upper valve sometimes are
spinose. Merrill (553) discussed the variation in sculpture
of Anomia aculeata Gmelin, an east American species.

The species of this genus are attached to rocks, shells,
or other objects and often acquire sculpture corresponding
to that of the object to which they are attached. Often
only upper valves are found on the beach, or as fossils,
because those become loose and are washed away, whereas
the lower valve remains attached.

Boulenger (554) mentioned that the byssal plug of
members of this genus apparently corrodes surfaces to
which it is attached and as a result the shell often lies sunk
into a pit of its own making.

The Recent species of Anomia in Great Britain have
received special study by Winckworth (555). Loosanoff
(556) discussed the metamorphosis of the east American
A. simplex d’Orbigny.

Anomia peruviana d’Orbigny
Plate 40, Figure 2; Plate 41, Figure 8

Anomia peruviana d’Orbigny, Voy. dans l’Amér. Mérid.,
Vol. 5, Pt. 3, p. 673, 1846. — Phillippi, Abbild. u.
Beschreib. Conchyl., Bd. 3, No. 8, p. 131 (1),
Anomia, pl. 1, figs. 2, 3, 1850. ‘‘Patria: Peru,”
Recent. — Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 240, pl. 12, figs. 2, 5, 1931. Various
localities cited, Pliocene to Recent. — Hertlein and
Strong, Bull. Amer. Mus. Nat. Hist., Vol. 107, Art. 2,
p. 177, 1955. “Pinas Bay, Panama.’ Recent. Also
earlier records. — Keen, Sea Shells of Tropical West
America (Stanford Univ. Press: Stanford, California),
p. 80, fig. 152, 1958. Monterey, California, to Paita,
Peru. — Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 177,
pl. 24, figs. 2-2f, 1961. Lower California to northern
Peru.

Type specimen. — British Museum (Natural History).

Type locality. — ‘taux environs de Payta (Perou).”

Range. — Late Miocene or early Pliocene (in
Ecuador, Olsson) to Recent. Recent from San Pedro
California, to Punta Penasco in the Gulf of California and
south to Paita, Peru, and the Galapagos Islands, from low
tide to 110 meters (60 fathoms) on rocks or on shells.

Occurrence in San Diego Fm. — C.A.S. 1137,
1400, 1413. L.A.M. 305, 305A, 305C.

Original description. — Coquille presque arrondie,
un peu carrée, plus longue que large, trés-déprimée,
marquee en dessus de quelques indices de cotes rayon-
mantes peu prononcées, nombreuses. Sa couleur est
verdatre trés-pale ou rosee; son intérieur est verdatre, le
ligament entierement vert. La valve inférieure a ses bords
desunis sur une grande largeur. Diameéetre, 33 milli-
metres. (d’Orbigny.)

Remarks. — Three upper valves of an Anomia are
present in the Academy’s collections from Pliocene strata
at San Diego. The largest one, 36.6 mm from beak to base,
is smooth but the other two bear radial ribs. These shells
are so similar to Recent specimens of Anomia peruviana
that there appears to be no reason to doubt their identity.
A few small valves referable to this species are in the col-
lections of the Los Angeles County Museum from Locs.
305, 305A and 305C (LAM).

Seven left (upper) valves in the collections of the

224

Los Angeles County Museum, the largest one 59 mm high,
were collected by Charles Sternberg at Pacific Beach.
According to the label these were from beds of Pliocene
age. The excellent preservation of the specimens as well
as the softness of the matrix leads us to question whether
these valves may have been collected from beds of Pleisto-
cene age which overlie the Pliocene strata at Pacific Beach.

Recent specimens of Anomia peruviana vary in
shape and in sculpture. They may be smooth exteriorly
or they may bear well developed radial ribs occasionally
bearing very short spines. Exterior sculpture of the shell
of Anomia may simulate that of the object to which it is
attached. Partly because of the multiplicity of forms re-
sulting from such situs this species has received a number
of names in the literature. The following are generally
considered to be synonyms: Anomia hamillus Gray, A.
larbas Gray, A. alectus Gray, A. lampe Gray, A. pacilus
Gray, ‘““Anomya” simplex Mabille.

Anomia fidenas Gray has been considered to be a
synonym of A. peruviana by many authors but Olsson
(557) recently accorded it specific status.

Anomia adamas Gray (558), originally described
from the Galapagos Islands and Lord Hood’s Island, was
said by E. K. Jordan (559) to differ from A. peruviana in
that the two distal muscle impressions of the upper valve
are equidistant from the umbo rather than nearly in a
straight line. It might be questionable whether or not this
criterion can be relied upon consistently to separate the
two species. Keen (1958, p. 80) considered A. adamas to
be a valid species, a distinction based chiefly on a radial
ribbing pattern on some specimens. A problem in con-
nection with A. adamas is the locality record “Lord
Hood’s Island.”’ There is a “Hood Island” in the Galapagos
group and “Lord Hood Island” in the Gambier Island
group. Several authors (560 have cited this species as
occurring in the southwestern Pacific. Whether it occurs
in both west American and western Pacific Islands is-open
to question.

Anomia limatula Dall was based upon large smooth
valves presumably from beds of Pleistocene age at Pacific
Beach. It is probably not more than subspecifically dif-
ferent from A. peruviana and some authors consider them
to be identical.

Anomia subcostata Conrad was originally described
from beds now believed to be of Pliocene age, in Imperial
Co., California. Hanna (561) mentioned the great variation
in a series of specimens and suggested that it is quite
possible that Conrad’s species may not be separable from
some of the Recent west American species.

Anomia peruviana has been reported from strata of
middle Pliocene age at Bahia Tortola (Turtle Bay), Lower
California and from deposits of Pleistocene age from
southern California to Peru. At the present time it lives
in quiet bays where it is attached to rocks or to empty
shells by a byssus which extends through a notch in the
lower valve. The pearly upper valves, which may be
white, green or yellow, are often found upon the beaches
where the species occurs. The lower valves often are not
found, or occur but sparsely among empty shells. This is
probably a result of the method of attachment.

Anomia limatula Dall

Anomia limatula Dall, Proc. U. S. Nat. Mus., Vol. 1, p.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

15, July 1, 1878. — Dall, Proc. U. S. Nat. Mus., Vol. 1,
pp. 27, 28, 1878. — Dall, Trans. Wagner Free Inst. Sci.,
Vol. 3, Pt. 4, p. 785, pl. 35, fig. 19, April, 1898.
“Pacific Beach near San Diego, Stearns.” “Pliocene.”
Also other localities, Pliocene and Pleistocene. —
Schuchert, Dall, et al., U. S. Nat. Mus., Bull. 53, Pt. 1,
p. 50, 1905. ‘“‘Pliocene. San Diego, California.”

Type specimen. — “Holotype” No. 7949, United
States National Museum. [“‘Plesiotypes” No. 154341
United States National Museum (Schuchert, Dall, et al.).
Specimens labeled “Original lot”? by Henry Hemphill are
Nos. 695, 695a, b, ec, California Academy of Sciences
Department of Geology type collection. |

Type locality. — “late Tertiary deposits of the
Californian coast,” San Diego. [Cited later (1878, p. 27)
from “Strata of the San Diego Peninsula,” also “strata on
the mainland” ‘“‘To the eastward of the town, or what is
known locally as the ‘railroad land’.’’]

Range. — Pleistocene.

Remarks. — Four upper (left) valves of Anomia
limatula labeled by Henry Hemphill “Original lot” from
“Foot of 30th street” in San Diego are in the collections
of the California Academy of Sciences. These evidently
came from beds of Pleistocene age. Schuchert, Dall, et al.,
cited the age of the ““Holotype”’ as “Pliocene” but there is
no evidence that it came from beds of that age. Dall
(1898) illustrated a specimen collected by Stearns at
Pacific Beach and cited the age as Pliocene. The valve
illustrated by Dall appears to be identical with those
collected by Hemphill.

The species which Dall (1878, pp. 27, 28) listed
with Anomia limatula indicate Pleistocene age for that
assemblage and Arnold (562) later cited it as occurring
only in deposits of that age. We know of no evidence
indicating that Anomia limatula occurs in the San Diego
Formation.

GENUS PODODESMUS PHILIPPI

Pododesmus Philippi, Wiegmann’s Archiv f. Naturgesch.
for 1837, Jahrg. 3, Bd. 1, p. 385. Sole species:
Pododesmus decipiens Philippi. — Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 4, pp. 770, 774, 1898.
Type: P. rudis Broderip. — Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1 p. 241, 1931. Type (by

monotypy): P. decipiens Philippi = Placunanomia
rudis Broderip, Cuba.
Type species (by monotypy). — Pododesmus

decipiens Philippi, 1837, p. 386, pl. 9, figs. 1a, 1b, le, 1d.
“Havana.” [= Placunanomia rudis Broderip, 1834,
illustrated by Reeve, Conch. Icon., Vol. 11, Placunanomia,
sp. 2, pl. 1, figs. 2a, 2b, August, 1859. “‘Hab. West Indies;
Broderip. Havana; Philippi.” Also, Abbott, American
Seashells (Van Nostrand Co., Inc.: New York), p. 372,
pl. 38, fig. b, 1954. — Olsson and Petit, Bull. Amer. Paleo.,
Vol. 47, No. 217, p. 529, pl. 77, fig. 1, 1964. Key West,
Florida, Recent. }

Range. — ?Eocene; late Oligocene, or early Miocene
to Recent. Recent from the intertidal zone to about 73
meters (46 fathoms), occasionally deeper.

Description. — Valves rounded, radiately grooved or
wrinkle-ribbed (but not plicated); lower (right) valve with
an open or sometimes nearly closed byssal foramen;

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

upper (left) valve with one striated byssal impression and
one muscle impression.

The crurum on the lower valve of the type species
of Pododesmus (described by Olsson and Petit) has “‘a
single crural process which arises as a ridge along the
posterior side of the central chalky area and at the dorsal
margin becomes enlarged into a prominent knob, its
dorsal face folded or bilobate in shape and carrying the
attachment scar of the ligament”’.

Remarks. — This genus differs from Placunanomia in
possessing an open byssal foramen in the lower valve,
although small or sealed over in the type species (563),
and in lacking large, well developed cardinal crura. It,
differs from Anomia in possessing only one muscle im-
pression (in addition to the byssal impression), rather than
two.

Knowledge of the generic and subgeneric assignment
of fossil specimens is often doubtful where the preserva-
tion is imperfect.

Beu (Trans. Roy. Soc. New Zealand, Zool., Vol. 9,
No. 18, p. 228, 1967) recently placed Placunanomia,
Pododesmus and Monia in a new subfamily Placunano-
miinae.

Species referred to Pododesmus were described by
von Ihering (564) from the lower Patagonian beds, be-
lieved to be of Eocene age, in Patagonia. The muscle im-
pressions on those fossils were imperfectly preserved and
confirmation of the generic assignment is desirable.
Soot-Ryen described Pododesmus puntarenensis (565)
from beds of Tertiary age at Punta Arenas, Chile.

Key to Subgenera of Pododesmus

A. Lower valve with a small
(sometimes nearly closed)
foramen . Pododesmus s. s.

B. Lower valve with a large

open foramen . . Monia

SUBGENUS MONIA GRAY

Monia Gray, Proc. Zool. Soc. London for 1849, p. 121,
issued between January and June, 1850. Several species
cited including Placunanomia macrochisma Broderip,
P. cepio Broderip, P. alope Broderip, P. patelliformis
Linnaeus, P. zealandica Gray, P. ione Gray, P. colon
Gray. — Beu, Trans. Roy. Soc. New Zealand, Zool.,
Vol. 9, No. 18, p. 229, November 2, 1967. Type as
designated by Kobelt.

Type species (designated by Kobelt, Illustr. Con-
chylienbuch, Bd. 2, p. 376, 1881). — “Typus ist Pla-
cunanomia zealandica. Quoy (Taf. 112 fig. 4) von
Neuseeland.”” [Anomia zealandica Gray in Dieffenbach’s
Travels in New Zealand, Vol. 2, p. 261, 1843. New
Zealand. Illustrated by Reeve, Conch. Icon., Vol. 11,
Placunanomia, sp. 4, pl. 1, fig. 4, 1859. New Zealand. —
Suter, Man. New Zealand Moll., p. 845, pl. 56, figs. 1,
la, 1913. — Beu, 1967, fig. 2e, f.]

Range. — Late Oligocene or early Miocene to
Recent.

Description. — The shell of this subgenus differs
from Pododesmus s. s. in possessing a large byssal opening

225

and in that the large perforation of the lower valve only
slightly embraces the large thin plug.

Beu (1967, p. 229) pointed out that the resilial
crurum on the type species of Monia is single and with
only a dorsal resilial surface. The interior in many of the
Recent species is usually greenish or brownish in colora-
tion.

Remarks. — Monia is reported to occur in western
North America and Japan from late Oligocene or early
Miocene to Recent, in Europe from Miocene to Recent,
in England, Pliocene to Recent. It is living in New Zealand
and Australia and probably occurs in strata of late
Tertiary age in that region.

According to Keen (566) the species described as
Placunanomia inornata by Gabb from beds of Eocene age
in California, and later assigned to Monia by Vokes (567),
is an Anomia.

Hayami (568) recently referred two species of early
Cretaceous age in Japan to Monia. The muscle impres-
sions of the species were not seen and therefore this record
of Monia in the Cretaceous needs confirmation.

Pododesmus (Monia) macrochisma Deshayes
Plate 40, Figure 3; Plate 41, Figures 9, 12, 13

Anomia macrochisma Deshayes, Rev. Zool., Soc. Cuvier-
ienne, December, 1839, p. 359. — Deshayes, Guerin’s
Mag. de Zool., 1841, pl. 34. — Philippi, Abbild. u.
Beschreib. Conchyl., Bd. 3, Heft 8, Anomia, p. 132
(2), pl. 1, fig. 4, November, 1850 (as Anomia
macroschisma). “‘Patria: Mare glaciale ad Kamtschatka,
Insulas Aleutas, et sinus Ochotensis.”

Placunanomia macroschisma Deshayes, Dall, Proc. Calif.
Acad. Sci., Vol. 5, p. 297, 1874. “well at San Diego.”

“Pliocene.”” — Dall, Proc. U. S. Nat. Mus., Vol. 1,
p. 28, 1878. “‘well-digging in stratum B“,” San Diego
well. — Cooper, Seventh Ann. Rept. Calif. State

Mineral., p. 260, 1888. ‘Pl. — San Diego well.’’ —
Orcutt, West Amer. Sci., Vol. 6, Whole No. 46, p. 85,
August, 1889. Dall’s record (1874) cited. — Orcutt,
quoted by Ellis in Ellis and Lee, U. S. G. S., Water
Supply Paper 446, p. 59, 1919. Dall’s record (1874)
cited. — Hertlein and Grant, Mem. San Diego Soc. Nat.
Hist., Vol. 2, Pt. 1, p. 48, 1944. Dall’s record (1874)
cited.

Pododesmus (Monia) macroschisma Deshayes, Dall, Trans.
Wagner Free Inst. Sci., Vol. 3, Pt. 4, p. 780, April,
1898. “Pliocene of San Diego, California, Hemphill.”
“Pliocene of the San Diego well.”” — Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 117, 1903. ‘Pliocene. —
San Diego well (Dall).”” — Waterfall, Univ. Calif. Publ.,
Bull. Dept. Geol. Sci., Vol. 18, No. 3, table opp. p. 78,
1928. “San Diego Pliocene.”

Pododesmus macroschisma Deshayes, Arnold, U. S. G. S.,
Prof. Paper 47, p. 28, 1906. ‘“‘San Diego formation ...
at Pacific Beach, north of San Diego.” — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
65, pl. 26, figs. la, 1b, (Recent), 1924. ‘Pliocene of
San Diego.”’ — Carson, Pan-Amer. Geol., Vol. 43, No.
4, p. 268, 1925. “San Diego fauna.” Pliocene. —
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.
1, p. 242, 1931. “San Diego well, Balboa Park, San
Diego (Dall, 1874).”

Monia macroschisma Deshayes, J. P. Smith, Proc. Calif.

226

Acad. Sci., Ser. 4, Vol. 3, p. 181, 1912. “San Diego-
Purisima.”” — J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4,
Vol. 9, No. 4, p. 151, 1919. “San Diego”’ Pliocene.

Pododesmus macroschismus Deshayes, Hertlein and Grant,
Mem. San Diego Soc. Nat. Hist., Vol. 2, Pt. 1, p. 48,
1944. Dall’s record (1874) cited.

Type specimen. — Location unknown to the present
authors.

Type locality. — ““Kamtschatka.” Recent.

Range. — Miocene to Recent. Recent from the
Bering Sea to Cape San Lucas, Lower Caliofrnia, and
Santa Inez Bay in the Gulf of Caliofrnia. From intertidal
zone to 73 meters (40 fathoms). Also Miocene to Recent
in Japan (569); Recent from Lat. 38° to 46°N., in Japan
Sea, and 39° to 47° N. in Pacific. Kamtschatka (570),
Pliocene to Recent.

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 1176, 1178, 1179, 1183, 1402, 1413,
1414. L.A.M. 122, 124, 302, 305, 305A. U.C. A-8333.
U.C.L.A. 301, 305, 2420.

Original description. — Testa irregulariter ovata,
inaequivalvi, albo-viridula, irregulariter plicata; valvaii
superiore convexa, inferiore plana, suprene late perforata,
foramine integro, marginibus acutis plicatis, valvis intus
submargaritaceis, superiore maculamagna satirate viridi
ornata. (Deshayes, 1839).

Remarks. — Numerous specimens, all single valves,
in the collections from the San Diego formation are
referable to this species. The largest specimen, a well pre-
served left (upper) valve, from Loc. 305 (LAM) is 77 mm
high, from dorsal to ventral margin, and 94 mm wide; the
smallest one is about 5 mm high. A large Recent specimen
102 mm high and 105 mm wide was reported from
Morrow Bay, California (see Min. Conch. Club South.
Calif., No. 190, p. 21, 1959). The fossil specimens vary in
thickness. Some are rather coarsely sculptured with radial
ribs, others bear fine sculpture as shown in Reeve’s
Illustrations of ‘‘Placunanomia’”’ cepio Gray and P. alope
Gray.

Fitch (571) stated that specimens of Pododesmus
occurring on abalone shells in southern California are
referable to the species described by Gray as Placunanomia
cepio (572), a species generally placed in synonymy of
Pododesmus macrochisma. Gray described P. cepio as
follows: “Scars 2, far apart; upper very large, ovate,
longitudinal, central; lower smaller, oblong, oblique,
rather behind the upper,” “Plug large, flat, broad. Notch
large wide.” Reeve illustrated a specimen under this name
and stated: “Shell orbicular, radiately minutely striated,
everywhere wrinkle-indented; transparent white; orifice
rather large.”

Placunanomia alope Gray (573), also described from
California, has well defined radial sculpture as stated by
Reeve, “‘In this species the ribs have an irregular character,
disposed in waved radiating wrinkles.”

The separation of P. cepio and P. alope from forms
of P. macrochisma is based chiefly upon the thinner shell
and finer sculpture. However, valves similar to P. alope
from San Miguel Island, California, in the collections of
the California Academy of Sciences, are accompanied by
large, thick, rather coarsely sculptured valves. The thick-
ness of the shell and the development of coarse or fine
radial sculpture (occasionally obsolete) varies greatly de-
pending upon the situs. Frizzell (574) mentioned a

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

specimen which grew in an empty tube of a Teredo.

F. S. MacNeil mentioned (pers. comm.) that speci-
mens referred to Pododesmus macrochisma from California
generally have a larger byssal foramen than those from
Alaska. We have examined this feature in a series of shells
from Bering Sea to Lower California, Mexico. We have
observed two rather thick Recent shells from Kodiak
Island, Alaska, in which the foramens are comparatively
small. However, somewhat thinner shells with larger
foramens also are present in the collection from the same
locality. Illustrations representing this species by Russian
(575) and by Japanese authors (576) reveal rather large
foramens. Size of the foramen does not appear to be
consistently different in northern and southern forms.

It is true that some specimens from west American
waters are similar to P. cepio and others to P. alope but
the variation in a large series is so great that there appear
to be no criteria to rely upon for separating the shells into
two or three species unless certain forms are arbitrarily
selected to represent various species. An examination of
a large series of specimens of P. macrochisma in the
Smithsonian Institution, and the type specimen of P.
alope, led Carpenter (577) to conclude that it “proves that
these forms are among the many varieties of P. macro-
chisma”’ (578). More recently Burch (579), after studying
a large series of specimens of Pododesmus from Puget
Sound and from Monterey, California, stated that he could
find no basis for the recognition of more than one species.

We have observed large coarsely ribbed specimens
referable to P. macrochisma which occur in beds of late
Pliocene age in Ventura Co., California.

A variety (580) of P. macrochisma was cescribed by
Kanehara from Hokkaido, Japan, from beds now believed
to be of Pliocene age.

Pododesmus newcombei Clark and Arnold (581)
was based upon a fossil from Vancouver Island, British
Columbia, in beds referred to late Oligocene age. The
type measures approximately, length 35 mm, height,
29 mm. It was described as differing from P. macrochisma
in the smaller size and fewer, coarser, radial ribs separated
by wider interspaces.

Pododesmus foliata Broderip (582), a Recent tropical
west American species, is sculptured with fine ribbing and
the color of the interior is brown.

SUBCLASS TELEODESMATA DALL
ORDER PACHYODONTIDA STEINMANN
SUPERFAMILY CHAMACEA BLAINVILLE (583)
FAMILY CHAMIDAE BLAINVILLE (584)

Shell substance three-fold, the inner layer porcel-
lanous and tubular, the middle obscurely prismatic, the
external cellulo-erystalline with reticulated tubules and an
inconspicuous epidermis; valves unequal, irregular, one of
them sessile; closed, usually rounded in form with con-
spicuous sculpture, often differing in the opposite valves;
adductor scars subequal, elongate, pedal scars minute,
distant; ligament and resilium external in a deep groove,
parivicular, opisthodetic; area distinct, prosodetic; beaks
more or less spiral, prosogyrous; pallial line simple; hinge-
plate heavy, arcuate; hinge frequently with a minute or
obsolete posterior lamina, chiefly in the fixed valve;

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

cardinals one or two in the free valve, two with an inter-
mediate socket in the fixed valve; the anterior cardinal
broad, usually deeply grooved or multifid, the posterior
simple, long, and curved parallel with the dorsal border.
(Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 3, pp.
541-542, 1895). Late Cretaceous to Recent.

Remarks. — The supraspecific units of this family
have been reviewed by Nicol (585). Many of the Recent
west American species of Chamidae were reviewed by
Pilsbry and Lowe (586) and others. Yonge recently dis-
cussed the “Form, Habit and Evolution in the Chamidae
(Bivalvia) with reference to conditions in the rudistids
(Hippuritacea)” (Phil. Trans. Roy. Soc. London, Ser. B.
Biol. Sci., No. B. 775, Vol. 252, pp. 49-105, figs. 1-31,
February 16, 1967).

GENUS CHAMA LINNAEUS (587)

Chama Linnaeus, Syst. Nat., ed. 10, p. 691, 1758. Several
species cited including Chama lazarus Linnaeus. —
Odhner, Kon. Svenska Vetensk. Akad. Handl., Bd. 59,
No. 3, p. 75, 1919.

Type species (designated by Schmidt, Versuch
Conchyl. Samml., pp. 63, 177, 194, 1818). — “Typ.
Chama Lazarus. No. 11. v. Born. tab. 5, fig. 12-14”.
[Chama lazarus Linnaeus, 1758, p. 691. “Habitat in
Mediterraneo, Americano.” Ref. to ““Rumph. mus. t. 48,
f. 3”, “Argenv. Conch, t. 23, f. F. I.”, “Brown, jam. t.
40, f. 9.’ Illustrated by Reeve, Conch. Icon., Vol. 4,
Chama, sp. 4, pl. 2, figs. 4a-b, 1846. For a discussion of
Chama lazarus see Dodge, Bull. Amer. Mus. Nat. Hist.,
Vol. 100, Art. 1, p. 138, 1952. ]

Range. — Late Cretaceous to Recent. Recent, shore
to about 160 meters (86 fathoms). One species cited from
a depth of 1250 meters.

Description. — Shell thick, attached at umbo of left
valve which is often cornucopia-shaped; very inequivalve,
the upper one the smaller; beaks prosogyrous, turned to
the right; ornamentation concentrically foliaceous and
irregularly lamellate or spinose; hinge tooth of upper valve
thick, curved, received between two teeth in the opposite
valve; ligament external but more or less sunken in a
groove; adductor impressions large; margin usually finely
crenellated.

Remarks. — Chama is separated from Pseudochama
Odhner, type Chama cristatella Lamarck, which is attached
by the right valve and has the beaks twisted to the left.
Yonge mentioned (1967, p. 56) that some species in the
Chamidae may be attached by either the right valve or the
left valve and that genera cannot be erected on this basis.
However, he stated that “It is also convenient, regardless
of species, to refer to ‘Chama’ and ‘Pseudochama’ thereby
denoted individuals attached by these valves.”

Douvillé (588) suggested that Chama may have been
derived from Corbis Cuvier [Fimbria Megerle von Muhl-
feld] by attaching one valve for support.

Only three species of Chama have been reported
from the Tertiary of western United States, one in the
Oligocene of western Washington, and one each in the
early Miocene and in the middle Pliocene of California.
Four species have been recorded from beds of late Pliocene
age in the Gulf of California region. This genus is here
recorded from the San Diego Formation for the first time.

The species of Chama live chiefly in warm marine

227

waters. Ten species live in west American waters, only
one of which ranges north to California.

Chama pellucida Broderip
Plate 43, Figure 12, 15

Chama pellucida Broderip, Proc. Zool. Soc. London for
1834, p. 149, issued April 3, 1835. — Broderip, Trans.
Zool. Soc. London, Vol. 1, p. 302, pl. 38, fig. 3, 1835.
Original locality cited. — Reeve, Conch. Icon., Vol. 4,
Chama, species 32, pl. 6, fig. 32, 1847. Original
locality cited. — Woodring and Stewart, in Woodring,
Stewart, and Richards, U. S. G. S., Prof. Paper 195,
p. 38, and list opposite p. 78, pl. 14, figs. 1-4, 10,
1941. Pecten zone, San Joaquin Formation, Kettleman
Hills, California, late Pliocene. — Abbott, American
Seashells (D. Van Nostrand Co., Inc.: New York),
p. 393, pl. 37, fig. a, 1954. Oregon to Chile. — Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 225, pl. 33, figs. 2, 2a;
pl. 34, fig. 5, 1961. Oregon to Chile, Recent.

Type specimen. — Syntypes Nos. 1950-11.1.63-65,
British Museum (Natural History).

Type locality. — “Hab. ad Peruviam. (Iquiqui).”
“Dredged up attached to stones, Mytili, and turbinated
shells, at a depth varying from nine to eleven fathoms,
from a bottom of coarse sand; and also found under stones
at low water mark.”

Range. — Late Miocene (Castaic Formation; Stanton,
1966); middle Pliocene to Recent. Recent, western
Oregon (Lat. 44° N.) to Cedros Island, Lower California,
Mexico. Santa Elena, Ecuador, to Tocopilla, and Juan
Fernandez Island, Chile. Intertidal zone to 46 meters (25
fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A,
318, 319.

Original description. — Chama testa alba roseo seu
rubro frucata vel strigata, lamellis frequentibus, frondibus
elongatis pellucidis; intus alba, limbo crenulata. (Broderip.)

Remarks. — This species is represented in the San
Diego Formation by numerous small specimens, the largest
is a left valve 17 mm high. A fragment 25 mm long bears
spines similar to those on Chama frondosa. A number of
small, eroded specimens are probably referable to this
species.

Chama frondosa is here reported from the San Diego
Formation for the first time. It has been reported from
California in beds of Pliocene age at Los Angeles, in the
San Joaquin Formation in Kettleman Hills, (and what is
probably this species) from the Santa Maria district. It has
been reported in beds of late Pliocene age in the Gulf of
California region but we have not seen specimens.

The reported distribution of this species from
Oregon to Chile, at the present time is an unusual one.
Specimens from California agree closely with illustrations
of this species by Broderip and by Reeve. We have not seen
specimens from south of Cedros Island, Mexico, in North
American waters. The species was not included by Keen
in her volume on tropical west American shells. Con-
firmation of the identity of the form from California and
Oregon with specimens from Peru is desirable.

The hinge teeth of this species in an early stage of
development, have been illustrated by Dall (589). Grieser
(590) published a paper dealing with the animal of Chama

228

pellucida and a recent paper by Yonge (1967) contains a
detailed discussion of various features of this species.

Chama chilensis Philippi (591), described from beds
of Quaternary age in Chile, was said to differ from C.
pellucida in possessing less projecting concentric lamellae,
which lack frondose extensions, as well as in differences
in details of the hinge.

ORDER HETERODONTIDA NEUMAYR
SUPERFAMILY CRASSATELLACEA MENKE (592)
FAMILY CRASSATELLIDAE MENKE

Shell porcellaneous, solid, subtriangular to oblong,
with convex or compressed umbones, the anterior side
shorter, higher and rounded, the posterior contracted,
flattened, pointed, or subtruncate. Hinge strong with
large cardinal teeth and laterals. Ligament internal, at-
tached to a resilifer groove between the cardinal teeth.
Surface smooth or with growth line sculpture, sometimes
concentrically undulate especially over the umbones.
Pallial line simple, the adductor scars usually impressed.
Ventral margin smooth or crenate. [Olsson, Mollusks of
the Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New
York), p. 179, 1961.] Cretaceous to Recent.

The members of this group live chiefly in warm
temperate and tropical waters. This family is well repre-
sented in the Eocene of western North America, but only
a few species have been reported from the later Tertiary
and Quaternary in this region.

GENUS CRASSINELLA GUPPY

Crassinella Guppy, Geol. Mag., Dec. 2, Vol. 1, p. 442,
October 1874. Sole species, Crassinella martinicensis
d’Orbigny. — Keen, Proc. Malacol. Soc. London, Vol.
23, Pt. 1, p. 30, 1938. ‘Genotype (by monotypy):
Crassinella martinicensis (D’Orbigny 1853) (= Crassa-
tella martinicensis D’Orbigny, 1853.” — Olsson and
Harbison, Acad. Nat. Sci. Philadelphia, Monogr. No. 8,
p. 72, 1953. ““Type by monotypy: Crassinella martin-
icensis_ d’Orbigny.”. — Korobkov, Metodicheskoe
Rukovodstvo Po Tretichnym Molluskam Plantincha-
tozhabernye [Lamellibranchiata] (Leningrad), p. 137,
1954. Type, Crassatella martinicensis d’Orbigny.

Not Crassinella Bayle, Explic. Carte France, Vol. 4,
Fasc. 1, Explic. t. 105, 1878.

Pseuderiphyla Fischer, Man. de Conchyl., p. 1022, June
15, 1887. Sole species, Crassatella martinicensis
d’Orbigny.

Type species (by monotypy). — Crassinella martin-
icensis d’Orbigny in Sagra, Hist . . . . Cubana, Vol. 7
(Moll., Vol. 2), p. 288,[?1845], Atlas, pl. 27, figs. 21,
22, 23, 1842. — Maury, Bull. Amer. Paleo., Vol. 10, No.
42, p. 330 (178), pl. 42 (31), fig. 2, 1925. ‘“Matura,”
Trinidad, “Upper Pliocene.” — Jung, Bull. Amer. Paleo.,
Vol. 55, No. 247, p. 352, pl. 22, figs. 1, 2, 1969.
Trinidad, early Pliocene.

Range. — Eocene (593) in Europe and Argentina,
late Oligocene (594) in the Americas, to Recent. Recent
in warm temperate and tropical waters, from 1 to 73 meters
(40 fathoms), and reported to a depth of 712 meters
(390 fathoms).

Description. — Shell small, solid, subtrigonal with

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

the lateral sides straight and subequal, the umbones
flattened with the small beaks pointing backwards or
opisthogyrate. Anterior side rounded, the posterior more
excavated, concave, its end obtuse or pointed. Ligament
is largely internal, the pit for the resilium forming a deep
socket in the hinge plate; it is bordered in each valve by
two strong cardinal teeth on the anterior side. Left valve
with a strong posterior lateral tooth bordered above by a
long linear socket. External surface smooth or with strong,
concentric lamellations. Pallial line simple, the ventral
margins plain. (Olsson and Harbison, 1953.)

Remarks. — This genus with small, trigonal, flattish,
concentrically sculptured valves, is here reported from
beds of Pliocene age in California for the first time.
However, it is known to occur in beds of that age in
Costa Rica and Ecuador.

The earliest geologic record of occurrence of
Crassinella in California is that of “‘Crassinella cf. C.
mexicana Pilsbry and Lowe”’ from strata of approximately
middle Miocene (595) age.

Six species have been reported from beds of
Pleistocene age in southern California and Lower Cali-
fornia. Four species have been reported living in tropical
and subtropical west American waters. The number of
valid forms will probably be reduced when the relation-
ship of the various west American species is known.

Crassinella branneri Arnold
Plate 43, Figures 24, 25, 28, 29

Astarte (Crassinella) branneri Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 127, pl. 18, fig. 12, June 27, 1903.

Crassinella branneri Arnold, Woodring, Bramlette, and
Kew, U. S. G. S., Prof. Paper 207, p. 82, pl. 36, figs.
1-6, 1946, “‘characteristic of the Palos Verdes sand.”

Type specimen. — No. 162527, United States
National Museum.

Type locality. — “from the upper San Pedro series
at Los Cerritos,” California. ‘‘Pleistocene.”

Range. — Middle Pliocene to late Pleistocene.

Occurrence in San Diego Fm. — L.A.M. 305.

Original description. — Shell small, subtrigonal,
equivalve, inequilateral, convex, thick; umbo small, sharp;
anterior dorsal margin straight to anterior extremity,
where it meets the arcuate ventral margin in an angle;
posterior dorsal margin evenly arcuate, sloping down to
rounded, posterior extremity; surface sculptured with
numerous angular, concentric undulations or ridges; lunule
long, narrow, extending to anterior extremity, and cir-
cumscribed by a narrow, angular ridge; ligament external,
not prominent; two prominent cardinal teeth in right
valve; one in left; no laterals; pallial line entire, running
from the middle of adductor scars; adductor scars sub-
equal, small. Dimensions. — Long. 10 mm; alt. 8.9 mm;
diam. 5 mm. (Arnold.)

Remarks. — Several valves of this Crassinella were
collected by G. P. Kanakoff near the Mexican boundary.
These agree well with the original description and appear
to be the species identified with Crassinella branneri by
Woodring, Bramlette, and Kew.

The original illustration depicts a left valve, ap-
parently rather thick and with a rather wide apical angle.
There is a discrepancy in the dimensions given in the
text and those on the explanation to the plate. Dr. W. P.

ere

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Woodring kindly informed us (written comm.,October 16,
1968) that the type specimen is 9.7 mm long. This
corresponds rather well with the dimension given as 10 mm
by Arnold on page 127 (text). Dr. Woodring also in-
formed us concerning the hinge and lateral armature both
of which agree well with the present specimens.

The anterior margin of the left valve of this species
is grooved toward the ventral margin and a posterior
lateral socket is parallel to the posterior margin through-
out its length and into which the margin of the right valve
fits. Some authors refer to the inner lamina (more strongly
developed ventrally) as a posterior lateral. A similar
anterior socket is present on the right valve.

There is considerable variation in the valves in the
present collection. The larger ones are less concave
posteriorly and are less strongly sculptured. The apical
angle varies from about 78° to 82°.

Crassinella branneri bears a close resemblance to C.
pacifica C. B. Adams (596), differing chiefly in the
narrower posterior ventral end of the shell. Crassinella
mexicana Pilsbry and Lowe (597) is nearly equilateral and
the posterior dorsal margin is but slightly concave in
outline.

Crassinella quintinensis Manger (598), described
from beds of Pleistocene age at San Quintin, Lower Cali-
fornia, appears to be referable to C. branneri. Specimens
from the type locality were identified as C. branneri by
EK. K. Jordan and they reveal no noticeable differences in
shell characters from Arnold’s species.

Woodring, Bramlette, and Kew, mention that a
“small race’ of C. branneri lives in Seammon’s Lagoon,
Lower California. We have observed specimens of C.
mexicana from that locality and further south at San
Hipolito Point, some of which in profile approach C.
pacifica. They may be but a subspecies of C. pacifica to
which nomenclatorial status such forms were referred by
Hertlein and Strong (599) and by Hoffstetter (600).

SUPERFAMILY CARDITACEA FLEMING (601)
FAMILY CARDITIDAE FLEMING

Shell suborbicular to subquadrangular, often cordate,
usually heavy, with large, prominent umbones, anteriorly
directed and varying in position from submedian to nearly
terminal, the anterior side commonly the shorter. Sculp-
ture consists typically of strong, radial ribs, usually noded,
the surface covered by a brown, hairy periostracum.
Ligament external. Hinge plate curved, usually with two
cardinal teeth in each valve, the posterior one elongate
and with the lateral teeth absent or more or less de-
generated. Pallial line simple, the ventral margin more or
less fluted or crenated by the ends of the radial ribs.
Byssus usually present. [Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York), p.
184, 1961.] Triassic to Recent.

This family is represented by numerous species in
the Paleogene of western North America, but the number
was reduced in the Neogene. Four genera are present in
the San Diego Formation. At the present time, carditids
with large, thick shells live in tropical and subtropical
waters, but small forms, which also occur in warm waters,
are abundant in temperate and even Arctic waters. Fre-
quently viviparous.

229

Freneix (602) discussed the development of the
ligament and the hinge characters of the Carditidae and
Yonge (603) discussed the functional morphology and
evolution within the Carditacea.

Key to Genera of Carditidae

A. — Shell high and subtrigonal
a. Hinge of left valve with an

anterior lateral tooth. Miodontiscus
aa. Hinge of left valve lacking
an anterior lateral tooth . . Cyclocardia

B. Shell oblong or elongately trapezoidal
a. Ventral margin of valves folded inward . Milneria
aa. Ventral margin of valves not folded

inward . Glans

GENUS CYCLOCARDIA CONRAD

Cyclocardia Conrad, Amer. Jour. Conch., Vol. 3, No. 2,
p. 191, September 5, 1868. Cardita borealis Conrad
and Cardita ventricosa Gould cited. — Lamy, Jour. de
Conchyl., Vol. 66, No. 4, p. 293, 1922. “Type V.
borealis Conrad.”’ — Stewart, Acad. Nat. Sci. Philadel-
phia, Spec. Paper No. 3, p. 150, 1930.

Arcturus Sowerby, Zool. Beechey’s Voy., Moll., p. 152,
1839. Arcturus rudis Humphrey MS in synon. of
Cardita borealis Conrad.

Not Arcturus Berthold in Latreille, 1827. Crustacea. Not
Arcturus Curtis. Lepidoptera.

Scalaricardita Sacco, Moll. Terr. Terz. Piemonte e Liguria,
Pt. 27, p. 22, September, 1899. Species cited, ‘““Miodon
(an Scalaricardita) scalaris (Sow.)’’, and in the synony-
my, Cardita producta Michelotti, 1847.

Type species (designated by Stoliczka, Mem. Geol.
Surv. India, Palaeont. Indica, Ser. 6, Cret. Fauna South.
India, Vol. 3, Pelecypoda, pp. XX, 281, 1871). — “Type,
C. borealis, Con.” [Amer. Mar. Conch., p. 39, pl. 8, fig. 1,
1831. Illustrated by Stearns, Proc. U. S. Nat. Mus., Vol.
13, No. 813, p. 215, pl. 16, fig. 8, 1890. (Fig. of type). —
Abbott, Amer. Seashells, p. 379, pl. 28, fig. t, 1954.]

Range. — Middle Oligocene (604) to Recent. Recent
from 18 to 2195 meters (10 to 1200 fathoms).

Original description. — Rounded, equivalve, radiately
costate, covered with a rough epidermis; hinge with two
robust teeth in the left valve, directed obliquely backward,
the posterior one elongated and slightly curved; anterior
tooth of the right valve rudimentary; pallial impression
entire. (Conrad, 1868.)

Remarks. — Cyclocardia Conrad is here retained in a
generic category because of the unsettled state of nomen-
clature concerning the type species of Cardita Bruguiére
(605) and Venericardia Lamarck. The species assigned to
Cyclocardia are usually rounded trigonal and covered with
a rough periostracum. The cardinal tooth on the right
valve of some species is bifid or grooved, but on others
this feature is only faintly developed.

Cyclocardia has been cited from widely separated
regions. It occurs in the Arctic, temperate, sub Antarctic,
and Antarctic (606) regions. Finlay and Marwick (607)
stated that in New Zealand, Cyclocardia first appeared in
the Duntroonian, late Oligocene, and last appeared in the

230

Awamoan, middle Miocene. Sieber (608) cited it from
late Tertiary beds in the Vienna basin. Hirayama (609)
listed 32 species, Recent and fossil, of small ‘‘Venericardia”
from Japan and stated that probably half of these are
referable to Cyclocardia. It has been reported from strata
of middle Oligocene age in Germany, and in western
North America Cyclocardia first appeared in late Oligocene
or early Miocene time. Recent species in this region occur
from the Arctic to slightly south of San Diego, California.
One species living in tropical west American waters was
recently assigned to Cyclocardia by Keen (Sea Shells of
Tropical West America, p. 109, 1971). Chavan (610)
briefly discussed the occurrence of Cyclocardia and
pointed out that it is essentially an American group.

Woods (611) long ago called attention to the similar-

ity existing between the late Tertiary species of Europe,
Cardita scalaris Sowerby, the type species of Scalaricardita,
and C. ventricosa Gould. The similarity is so great that it
leads to the placement of Scalaricardita Sacco in the
synonymy of Cyclocardia as was recently done by Sieber.

Key to Species of Cyclocardia

A. Radial ribs 14 to 17; dorsal-

ventral elongation occidentalis
B. Radial ribs 18 to 20; anterior-
posterior elongation ventricosa

Cyclocardia occidentalis Conrad
Plate 43, Figures 4-6, 9-11

C[ardita]. occidentalis Conrad, Proc. Acad. Nat. Sci.
Philadelphia, Vol. 7, p. 267, February, 1855. — Conrad,
U. S. Pac. Railroad Expl., Vol. 6, Pt. 2, No. 2, p. 73,
pl. 5, fig. 24, 1857. “Locality. — Santa Barbara,
California.”

Cardita monilicosta Gabb, Proc. Acad. Nat. Sci. Philadel-
phia, Vol. 13, p. 371, November, 1861. “From the
Tertiary (probably Miocene) of Santa Barbara, Cal.”

Venericardia borealis Conrad, Dall, Proc. Calif. Acad. Sci.,
Vol. 5, p. 297, 1874. “well at San Diego.” “Pliocene.”
— Cooper, Calif. State Min. Bur., Seventh Ann. Rept.
State Mineral., p. 269, 1888. “Pl. — San Fernando,
Los Angeles County; Santa Barbara to San Diego.” —
Orcutt, West Amer. Sci., Vol. 6, Whole No. 46, p. 85,
1889. Dall’s record (1874) cited. — Orcutt, cited by
Ellis in Ellis and Lee, U. S. G. S., Water Supply Paper
446, p. 59,1919. Dall’s record (1874) cited. — Hertlein
and Grant, Mem. San Diego Soc. Nat. Hist., Vol. 2,
pt. 1, p. 48, 1944. Dall’s record (1874) cited.

Not Venericardia borealis Conrad, 1831.

Venericardia monilicosta Gabb, Dall, Proc. U. S. Nat. Mus.,
Vol. 1, pp. 11, 28, 1878. P. 28 “well-digging in stratum
B2, “San Diego, California.” — Orcutt, West Amer.
Sci., Vol. 6, Whole No. 46, p. 86, 1889. Dall’s record
(1878) cited. — Orcutt, cited by Ellis in Ellis and Lee,
U. S. G. S. Water Supply Paper 446, p. 60, 1919.
Dall’s record (1878) cited. — Arnold, U.S. G. S., Bull.
321, p. 32, pl. 14, fig. 2, 1907. “Fernando formation,
Bath-house Beach, Santa Barbara.” ‘Fernando (Plio-
cene).” [ Pleistocene. |

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Venericardia ventricosa Gould, Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 129, 1903. “Pliocene. — San Fernando;
Santa Barbara to San Diego (Cooper): San Pedro;
Santa Barbara (Arnold).” Also other records.

Not Venericardia ventricosa Gould, Proc. Boston Soc. Nat.
Hist., Vol. 3, p. 276, July 1850. “Hab. Puget Sound.”

Type specimen. — “not known to be extant”
(Woodring, 1946).

Type locality. — “Occurs with the preceding” [that
is] “Locality. — California.” In 1857 cited from “Santa
Barbara, California.”

Range. — Middle and late Pliocene and Pleistocene
of southern California.

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 12096. L.A.M. 305A, 318, 323. S.D.
75, 124, 2359.

Original description (of Cardita occidentalis). —
Subtriangular, equilateral; ventricose; ribs 15, rounded,
wider than the interstices, and regularly granulated by
transverse lines. (Conrad, 1855.)

“Allied to C. , of the San Pedro recent
formation, but proportionally more elevated and having
more prominent granules.”’ (Conrad, 1855.)

Original description of Cardita monilicosta. — Shell
nearly circular; beaks small, submedian, cardinal border
straight or faintly arcuate. Surface marked by from four-
teen to seventeen large rounded ribs, strongly moniliform;
interspaces narrow, acute. Posterior muscular impres-
sions largest. Pallial line broad and distinct but not im-
pressed. Internal margin coarsely crenulate, one large
square tooth, corresponding with each interspace between
the ribs; extreme edge undulated. Hinge robust. Length,
0.19 in.; width, 0.2 in.; depth of single valve, 0.05 in.
(Gabb, 1861.)

Remarks. — Three specimens with both valves and
four single valves of a Cyclocardia collected by Henry
Hemphill from the San Diego well are in the collections
of the California Academy of Sciences. The largest
specimen is 12.6 mm long, 11.4 mm high, convexity (both
valves together), 9 mm. These have about 15 nodulose
ribs. The original label cites “‘Venericardia ventricosa Gld.
= monilicosta Gabb.” A left valve in the collection of the
University of California at Los Angeles from North Snyder
School, Cabrillo Freeway, in San Diego, is 13.7 mm long,
14 mm high, convexity, 5.1 mm. Four very small single
valves from Loc. 323 (LAM) are referable to this species.

The correct identification of these specimens is
fraught with certain difficulties. For this reason the
original descriptions of both Cardita occidentalis and C.
monilicosta Gabb are included in the present work.

The specific name occidentalis appears to be the
earliest name applicable to the present specimens. The
description is applicable and the original illustration, al-
though not satisfactory, has in general the outline and the
sculpture similar to that of the present specimens.

The later name Cardita monilicosta Gabb, also based
on specimens from Santa Barbara, has been relegated to
the synonymy of C. occidentalis by various authors. Judg-
ing from the description, this appears to be the logical
course.

The present specimens agree almost exactly with
the illustration given by Arnold of a specimen from beds
of Pleistocene age at Santa Barbara, California, under the
name Venericardia monilicosta Gabb. This is certainly

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

referable to the same species illustrated by Woodring,
Bramlette, and Kew (612) under the name of Cardita aff.
C. occidentalis Conrad from Pleistocene beds at San
Pedro, California, shown on their plate 33, figure 4. The
specimens illustrated under the same name on their plate
31, figures 9 and 10, are more elongately rounded in out-
line and with flatter, less nodose ribs, and bear a resemb-
lance to the C. ventricosa series discussed by Smith and
Gordon (613). Quayle (614) believed that C. occidentalis
and C. monilicosta are separable, basing his conclusions
upon measurements of specimens.

Willett (615) mentioned the probable identity of C.
occidentalis with C. monilicosta and he also mentioned a
resemblance to C. stearnsii Dall (616), which, however, isa
distinct species living in Puget Sound. Woodring, Bram-
lette, and Kew, (1946, p. 85) pointed out that the nodulose
specimen illustrated on their plate 33, figure 4 bears a
resemblance to C. californica Dall (617). The latter species
does bear a general resemblance to C. occidentalis but is
more narrowly trigonal in outline and the ribs, about
14-16 in number, are very coarsely nodulose and the shell
is larger and quite thick.

A study of the small specimen, upon which the
senior author based the record (618) of Venericardia
californica Dall from the San Diego formation, reveals that
it can be referred to C. occidentalis.

Fossils described under the name of Cardila monili-
costa Gabb var. ochotica Slodkewitsch (619) from the
Kavran Series of Pliocene age in western Kamtschatka,
resemble Gabb’s species in general characters but are said
to possess 21-23 radial ribs and the outline of the shell
was said to be more rounded. Perhaps this is the form
cited by Tikonovich (620) from beds of Pliocene age on
the Schmidt Peninsula, Sakhalin Island. According to
Slodkewitsch, typical C. monilicosta Gabb was not found
by him among the collections from Sakhalin or
Kamtschatka.

Cyclocardia ventricosa Gould
Plate 43, Figures 3, 8

Cardita ventricosa Gould, Proc. Boston Soc. Nat. Hist.,
Vol. 3, p. 276, July, 1850. — Gould, U. S. Explor.
Exped., Vol. 12, p. 417, 1852, Atlas, p. 14, pl. 36,
figs. 532, 532a, 1856. — Gould, Otia Conch., pp. 83,
246, 1862. “Hab. Puget Sound.” — A. G. Smith and
Gordon, Proc. Calif. Acad. Scil, Ser. 4, Vol. 26, No. 8,
pp. 214, 215, figs. 4A, B, 1948. “Puget Sound.”’ Recent.

Venericardia ventricosa Gould, J. P. Smith, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 3, pp. 174, 182, 1912. “San
Diego-Purisima.”” — I. S. Oldroyd, Publ. Puget Sound
Biol. Sta., Vol. 4, p. 36, pl. 3, fig. 8, 1924. Puget
Sound. — I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 114, 1924. ‘‘Range. Belkoffski
Bay, Alaska, to the Coronado Islands and Cortez Bank.”

Type specimen. — Syntypes No. 3373, United States
National Museum; also Syntype No. 216813, Museum of
Comparative Zoology, Harvard University (Johnson, U. S.
Nat. Mus., Bull. 239, p. 165, 1964).

Type locality. — “Hab. Puget Sound.”

Range. — Middle Pliocene to Recent. Recent from
Belkoffski Bay, Alaska, to the Coronado Islands and
Cortez Bank, Mexico, in 37 to 272 meters (20 to 149
fathoms).

231

Occurrence in San Diego Fm. — L.A.M. 305, 305A.

Original description. — Testa solida, ventricosa,
ovato-trigona vix obliqua, radiatim 18-20 costata, costis
concentrice subnodosis, interstitiis angustis, epidermide
fuliginoso, villoso induta; umbonibus submedianis, obtusis;
intus alba; margine profundeé crenulato; dente cardinali
valvae dextrae, elevato, crasso, triangulari. Lat. 3/4; alt.
5/8; lat. 1/2 poll. (Gould).

Compared with C. borealis, Conr., it is thicker, less
transverse, more tumid at the beaks, which are less
recurved; the ribs are barred; the cardinal tooth is short,
triangular (not long falcate) and detached from the margin;
the crenulations of the margin deeper. (Gould.)

Remarks. — The largest of four single valves from
Loc. 305 (LAM) is a left valve 16.2 mm long and 15 mm
high. There are 18 radial ribs of which the posterior 5 or
6 are smaller than the others. This valve as well as the
smaller ones, compares favorably with Recent specimens
of Cyclocardia ventricosa from Puget Sound and California.

So far as we can ascertain, most of the earlier
records of this species from the San Diego Formation were
based upon Dall’s record (1874) which is referable to
Cyclocardia occidentalis Conrad. The shell of C. ventricosa
is more elongately (anterior-posterior) rounded and is
sculptured with 18 to 20 rather than 14 to 17 radial ribs.

A Recent form from Monterey, California, more
elongate (anterior-posterior) than usual for this species
was named C. ventricosa montereyensis (621) by A. G.
Smith and Gordon. Inspection of a large series of speci-
mens of this subspecies reveals that there are forms which
imperceptibly grade into typical C. ventricosa.

A small southern form, more rounded in outline
and more inflated, with more sharply defined ribs, was
described as C. ventricosa redondoensis by J. Q. Burch
(622).

Wood (623) mentioned a close resemblance of
Cardita scalaris in the Coralline and Red Crag of England
to C. ventricosa. However, his description of the Crag
fossil calls for 20 to 22 radial ribs and his figure suggests
a more trigonal shell.

Cyclocardia inflata Hayasaka and Uozumi (624),
described from beds of late Oligocene or early Miocene
age in Japan, was said to be more rounded in outline and
the umbo lower than that of C. ventricosa.

Barnard and Ziesenhenne (625) mentioned the
occurrence of 132 specimens of Cyclocardia ventricosa
per square meter on an “Amphiodia-Cardita”’ bottom off
southern California.

Viviparity in this and other species of the Carditidae
was discussed by Jones (626). A detailed discussion of
C. ventricosa was published recently by Yonge (Proc.
Malacol. Soc. London, Vol. 38, Pt. 6, pp. 494-505,
figs. 1-9, 19, 24a, December, 1969).

GENUS GLANS MERGERLE VON MUHLFELD

Glans Megerle von Muhlfeld, Mag. Gesell. Naturfor.
Freunde zu Berlin, year 5, p. 68, 1811. Sole species,
Glans trapezia Linnaeus. — Lamy, Jour. de. Conchyl.,
Vol. 66, No. 3, p. 222, 1922. “‘Type: C. trapezia
Linne.”’ — Palmer, Geol. Soc. Amer., Mem. 76, p. 82,
1958. “Type species by monotypy Glans trapezia
(Linnaeus).”

232

Type species (by monotypy). — Glans trapezia
Linnaeus [= Chama trapezia Linnaeus, Syst. Nat., ed. 12,
p. 1138, 1767. “Habitat in Oceano Norvegico.”’ Illustrated
by Bucquoy, Dautzenberg, and Dollfus, Moll. Mar.
Roussillon, Vol. 2, Fase. 6, p. 231, pl. 38, figs. 21-25,
1892. — Dollfus and Dautzenberg, Mém. Soc. Géol. France,
Paléo., Vol. 16, Fasc. 2, Mém. No. 27, p. 292, pl. 12
(Mém. pl. 20), figs. 16-23, 1909 [as Cardita (Glans)
trapezia|. Aquitanian, Miocene to Recent. Does not
occur in Norway (p. 294). — Cossmann and Peyrot, Act.
Soc. Linn. Bordeaux, Vol. 66 (Conch. Néog. de l’ Aquitaine,
Vol. 2, Livr. 1), p. 31, figure of hinge, 1912.]

Range. — Paleocene to Recent. Recent from the
intertidal zone to 91 meters (50 fathoms).

Description. — Shell bearing a general resemblance
to carditids such as Carditamera but small, subquadrate in
outline; hinge with well developed anterior and posterior
laterals.

Remarks. — This genus is represented by one species,
occurring both as a fossil and Recent, in western United
States. Cardita naviformis Reeve (627), which lives in
waters off the coast of Chile, also has been assigned to this
genus.

Paraglans Chavan (628) was proposed as a subgenus
to include a number of Eocene species formerly placed in
the genus Glans.

Glans subquadrata Carpenter
Plate 43, Figures 16, 18, 19, 22, 30

Lazaria subquadrata Carpenter, Rept. Brit. Assoc. Adv.
Sci. for 1863, pp. 536, 627, 642, issued August; 1864.
Reprint in Smithsonian Misc. Coll., No. 252, pp. 22,
113, 128, 1872. — Carpenter, Ann. Mag. Nat. Hist.,
Ser. 3, Vol. 15, p. 178, 1865. Reprint, 1872, p. 280.
“Hab. Sta. Barbara (Jewett); Monterey, and along the
coast to S. Pedro (State Coll. no. 403) (Cooper).”

Cardita (Carditamera) subquadrata Carpenter, Dall, Proc.
Acad. Nat. Sci. Philadelphia, Vol. 54, Pt. 4, p. 707,
1902. Queen Charlotte Islands, Canada, to Todos
Santos Bay, Lower California.

Not Cardita subquadrata Conrad, Proc. Acad. Nat. Sci.
Philadelphia, Vol. 3, p. 298, 1847. “Eocene rocks in
St. Matthew’s Parish, Orangeburg District, S. D.”

Not Cardita subquadrata Gabb, Jour. Acad. Nat. Sci.
Philadelphia, Ser. 2, Vol. 4, p. 303, pl. 48, figs. 22a,
22b [indicated as 21a, 21b on plate], March, 1860.
New Jersey, Cretaceous.

C[ardita]. (Carditamera) carpenteri Lamy, Jour. de
Conchyl., Vol. 66, No. 3, p. 264, June 20, 1922. New
name for Lazaria subquadrata Carpenter.

Glans minuscula Grant and Gale, Mem. San Diego Soc.
Nat. Hist., Vol. 1, p. 277, pl. 13, figs. 10a, 10b,
November 3, 1931. Pleistocene and Recent. New
name for Lazaria subquadrata Carpenter.

Glans subquadrata Carpenter, K. V. W. Palmer, Geol. Soc.
Amer., Mem. 76, p. 82, pl. 7, figs. 1-4 (syntypes),
1958. Earlier records cited.

Type specimen. — Syntypes in United States

National Museum, No. 15681 (Palmer, 1958).

Type locality. — “Recent. Monterey, California

(type)” (Palmer, 1958). Several localities originally indi-

cated by Carpenter, including ““Neighbourhood of Mont-

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

erey.” “Neighbourhood of Sta. Barbara.” “‘Vancouver
Island, Straits of S. Juan de Fuca, and adjoining shore of
Washington Territory...”

Range. — Middle Pliocene to Recent. Recent from
Queen Charlotte Islands, British Columbia, to Todos
Santos Bay, Lower California, from intertidal zone to 91
meters (50 fathoms). Usually in shallow marine waters,
attached to the underside of stones or other objects.

Occurrence in San Diego Fm. — L.A.M. 305, 305A.

Original description. — “Hinge of Lazaria: outside
like Cardita variegata, jun.” (Carpenter, 1864).

L. testa extus Carditae variegatae jun. simili; pallida,
castaneo tincta; subquadrata, antice truncata, subregulariter
ventricosa, dorsaliter tumida; costis radiantibus cire. xiv-
xvi., tumidis, nodosis, diagonalibus majoribus; interstitiis
plus minusve insculptis: intus, valva dextra dente cardinali
triangulari, inter duas fossas sito, haud elongato; dent. lat.
a cardine separatis, ant. extante, post. obsoleto, calloso:
v. sinistrali dent. card. ii. angustis, subaequalibus, radiant-
ibus; lat. ant. et post. extantibus: cicatr. adduct. sub-
rotundatis. Long. .37, lat. .25, alt. .34. (Carpenter, 1865.)

The outside of this remarkable little species is
typically carditoid; the hinge is intermediate between
Lazaria and Cypricardia. (Carpenter, 1865.)

Remarks. — A number of single valves of this species,
the largest one 5.8 mm long, was collected by G. P.
Kanakoff near the Mexican boundary. The shell characters
of these are identical with those of Recent specimens from
adjacent waters.

Lamy, and later Grant and Gale, placed Lazaria
subquadrata Carpenter in the genus Cardita. They there-
fore proposed a new specific name for Carpenter’s species
because of the prior Cardita subquadrata Conrad, 1847,
and of Gabb, 1860. Woodring, Bramlette, and Kew (629),
and later Palmer, pointed out that if Carpenter’s species
is not referable to the genus Cardita or if the species de-
scribed by Conrad and by Gabb are not assigned to the
genus Glans then a new name is not necessary for Lazaria
subquadrata. According to Woodring, Bramlette, and
Kew, “it is improbable that either Conrad’s or Gabb’s
Cardita subquadrata is to be assigned to Glans.”

The only other reported occurrence of Glans sub-
quadrata in beds of undoubted Pliocene age is in the
Cebada Member of the Careaga Sandstone in the Santa
Maria district.

Orcutt (630) reported Cardita subquadrata from
strata of “Tertiary” age at Pacific Beach but his query
“?Pleist.”” leads us to omit assignment of his record to the
San Diego Formation.

A detailed discussion of this species was published
recently by Yonge (Proc. Malacol. Soc. London, Vol. 38,
Pt. 6, pp. 505-509, figs. 10-13, 20-22, 1969).

GENUS MIODONTISCUS DALL

Miodon Carpenter, Rept. Brit. Assoc. Adv. Sci. for 1863,
pp. 611, 627, 642, 682, August, 1864. Reprint in
Smithsonian Mise. Coll., No. 252, pp. 97, 113, 128,
168, 1872. Species originally cited: “Miodon pro-
longatus”’; “‘Astarte orbicularis, J. Sby.”; ‘‘Cardita
corbis.”’ — Dall, Proc. Acad. Nat. Sci. Philadelphia, Vol.
54, Pt. 4, p. 700, January 20, 1903. ‘Type M. pro-
longatus Carpenter.”

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Not Miodon Duméril, 1859; not Miodon Sandberger, 1870.
Miodontiscus Dall, Nautilus, Vol. 16, No. 12, p. 143, April,
1903. A new name for Miodon Carpenter, 1864, not

Miodon Dumeéril, 1859, nor Miodon Sandberger, 1870.

— Lamy, Jour. De Conchyl., Vol. 66, No. 4, p. 293,
1922. “type: V. prolongata Cpr.” — K. V. W. Palmer,
Geol. Soc. Amer., Mem. 76, p. 83, 1958. ““Type species
by original designation M. prolongatus Carpenter.”

Type species (by subsequent designation, Dall,
1903): “Type M. prolongatus Carpenter.” [The use of
“n. subg. n. s.” by Carpenter (1864, p. 627), is considered
by K. V. W. Palmer, 1958, to be an original designation
of M. prolongatus as type species. |

Range. — Miocene to Recent. Recent in from 9 to
128 meters (5 to 70 fathoms).

Description (of Miodon Carpenter). — Shell ovately
subtrigonal, small, solid, ventrally much produced, with the
umbones situated anteriorly, radiately ribbed, the ribs
being partially intersected by concentric sulcations; hinge
in the right valve with one posterior cardinal and one ant-
erior lateral tooth, left valve with one triangular anterior
and one elongated posterior cardinal, and a very small
anterior lateral tooth. Closely allied to Pleuromeris.
(Tryon, G. W., Jr., Structural and Systematic Conchology,
Vol. 3, p. 233, 1884.)

Remarks. — Dall, 1903, mentioned that this genus
is similar to Pteromeris Conrad (631) “but not compressed,
and with the posterior (instead of the anterior) right
cardinal absent and a posterior right and anterior left
lateral developed feebly.”

Iredale (632) believed Miodontiscus to be a synonym
of Coripia De Gregorio (633) but Dall and most later
authors consider Coripia to be a synonym of Pteromeris.

Miodontiscus has been reported from beds of
Miocene age in Japan but up to the present time it has not
been recorded earlier than middle Pliocene in western
North America.

Miodontiscus prolongatus Carpenter
Plate 56, Figures 1-5

Miodon prolongatus Carpenter, Rept. Brit. Assoc. Adv.
Sci. for 1863, pp. 611, 627, 642, issued August, 1864.
Reprint in Smithsonian Mise. Coll., No. 252, pp. 97,
113, 128, 1872. P. 97 ‘“(Neeah Bay, Swan)“, p. 128,
indicated as from ‘“‘Vancouver Island, Straits of S. Juan
de Fuca, and adjoining shores of Washington Ter-
itory ...” — Carpenter, Ann. Mag. Nat. Hist., Ser. 3,
Vol. 14, p. 424, December, 1864. Reprint in
Smithsonian Misc. Coll., No. 272, p. 236, 1872. “from
Vancouver District.’”” — Stearns, Proc. U. S. Nat. Mus.,
Vol. 13, No. 813, p. 217, pl. 16, figs. 7, 9, 1890.
“from Neeah Bay, and Mr. Dall obtained several
examples in the Alaskan region at Middleton Island.”
[Figured specimen from Middleton Island. ]

Venericardia (Miodontiscus) prolongata Carpenter, I. S.
Oldroyd, Publ. Puget Sound Biol. Sta., Vol. 4, p. 36,
pl. 16, figs. 5, 6, March, 1924. Middleton Island,
Alaska, to San Diego, California. — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
115, pl. 2, figs. 5, 6, 1924 (as Venericardia prolongata).
[Same illustrations and range as in preceding reference. ]

Cardita (Miodontiscus) prolongata Carpenter, Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 276,

1931. Pleistocene to Recent.

Miodontiscus prolongatus Carpenter, Chavan, Compt.
Rend. Sci. Soc. Géol. France, No. 10, p. 122, 1937. —
K. V. W. Palmer, Geol. Soc. Amer., Mem. 76,
p. 83, pl. 8, figs. 1-7, 1958. Earlier records cited.
Syntype illustrated.

Type specimens. — “‘Syntypes. — U. S. National
Museum, no. 15472; Redpath Museum, no. 2377”
(K. V. W. Palmer, 1958).

Type locality. — “‘Neah Bay, Washington (type)”
(Palmer).

Range. — Middle Pliocene to Recent. Recent from
Middleton Island, Alaska, to San Diego, California, in 9 to
55 meters (5 to 30 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 309,
323.

Original description. — “Outside Lucinoid; hinge
and scars nearer to Venericardia. Congeneric with Astarte
orbicularis, J. Sby. Min. Conch. pl. 444, f. 2, 3 (non
ejusdem, pl. 520, f. 2). G. Oolite; and with the Crag
Cardita corbis.”’ (Carpenter, August, 1864.)

Supplementary description: M. testa parva, solida,
tumida, compacta, albida; ventraliter antice valde prolong-
ata, excurvata; lunula longa, rectiore, haud impressa;
umbonibus antice inflectis, obtusis, valde prominentibus;
margine dorsali postico parum excurvato; costis radiant-
ibus, x.-xii. latis, obtusis, marginem attingentibus, parum
expressis, dorsaliter obsoletis, a liris incrementi concen-
tricis, plus minusve distantibus, expressis, hic et illic
interruptis: intus, margine a costis plus minusve obsoletim
crenulato; cardine dentibus v. dextr., uno postico, inter
duas fossas elongato, et. lat. ant. lunulari; v. sinistr., dent.
ant. triangulari, post. valde elongato, lat. ant. minimo,
obsoleto; cicatr. add. subrotundatis, ventraliter sitis.
Long. .23, lat. .24, alt. .16. (Carpenter, December, 1864,
p. 424.)

Remarks. — Typical specimens of Miodontiscus
prolongatus are about 5 mm in length and in height.
They are trigonally subcircular in outline with rather
prominent, erect beaks which are slightly curved anter-
iorly. The external sculpture consists of broad, low,
radiating ribs and widely spaced concentric, incised lines.

About 20 single valves in the present collection are
referable to Miodontiscus prolongatus. The largest one, a
left valve (ventral margin imperfect), is 7.9 mm high and
6.8 mm wide. Some of the valves are considerably eroded
but the observable shell characters agree well with Recent
specimens of Carpenter’s species.

Woodring (634) reported comparable specimens
from the Cebada and Graciosa members of the Careaga
Formation in Santa Barbara Co. He considered Veneri-
cardia yatesi Arnold (635) to be a synonym of M. pro-
longatus.

Carpenter’s description of M. prolongatus calls for
10 to 12 radiating ribs and the illustrations by Palmer
show about this number. Arnold’s description of Veneri-
cardia yatesi calls for 8 to 9 radial ribs. We have not
studied a series of Arnold’s species and can offer no
opinion as to its identity with M. prolongatus, but it seems
likely that variation in the species may be sufficient to
justify placing it in the synonymy of Carpenter’s species.

Slodkewitsch (636) reported M. prolongatus from
beds of late Tertiary age in western Kamtschatka as did
Pleshakov (637). However, according to Slodkewitsch,

234

his specimens are sculptured with 18 to 21 radial ribs.
Those specimens, no doubt, are referable to some other
species.

Cardita (Miodontiscus) nakamurai annakensis Oino-
mikado (638) described from the late Tertiary of Japan
was compared by its author with M. prolongatus.

GENUS MILNERIA DALL

Ceropsis Dall, Amer. Jour. Conch., Vol. 7, Pt. 2, p. 152,
November 2, 1871.

Not Ceropsis Gay and Solier, 1839. Coleoptera.

Milneria Dall, Amer. Nat., Vol. 15, No. 9, p. 718, Septem-
ber, 1881. A new name for Ceropsis Dall, 1871, not
Ceropsis Gay and Solier, 1839. — Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 6, p. 1411, October, 1903.
“Type Ceropsis minima Dall, 1871.” — Lamy, Jour. de
Conchyl.,Vol. 81, No. 4, p. 299, 1937.

Type species (by original designation). — “Type
Ceropsis minima, n. s.”

Range. — Middle Pliocene to Recent. Recent from
Monterey, California, to Punta Abreojos, Lower Cali-
fornia, and Guadalupe Island, from the intertidal zone to
27 meters (15 fathoms).

Description. — Shell with two left and three right
cardinals, the posterior left lateral, posterior and anterior
right cardinals minute and hardly recognizable except in
very well-developed specimens, in which the formula is

L. 1.01010.
R. 0.10101.

The female has a dome-like indentation rising from the
ventral margin of the valves, which is closed only by an
extension of the mantle edge and therefore not included
within the shut valves. The animal is minute, byssiferous,
and a nestler on flat surfaces, like the backs of the.shells
of Haliotis. (Dall, 1903).

Remarks. — This genus is dioecious. The young are
incubated in a fold in the mantle until they pass the
prodissoconch stage.

This is the first record of the occurrence of Milneria
in the San Deigo Formation. The genus was reported by
Vedder (639) from strata of late Pliocene age in the Los
Angeles basin. It also was reported by Woodring from
beds of Pleistocene age in the Palos Verdes Hills, San
Pedro, California.

Milneria minima Dall
Plate 43, Figures 1, 2, 14

Ceropsis minima Dall, Amer. Jour. Conch., Vol. 7, Pt. 2,
p. 152, pl. 16, figs. 5, 6, November 2, 1871.

Milneria minima Dall, Lamy, Jour. de Conchyl., Vol. 66,
No. 4, p. 353, fig. (p. 352), 1922. San Diego, Cali-
fornia. — I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 117, pl. 54, figs. 29, 30, 31, 1924.
“Monterey, California, to Rosario Bay, Lower Cali-
fornia.”” — Lamy, Jour. de Conchyl., Vol. 81, No. 4,
p. 299, fig. 9 (1, 2), 1937. — Franc, Traité de Zool.,
Tom. 5, Fasc. 2, p. 2095, fig. 1774, 1960. “de
California.”

Type specimen. —

National Museum.

No. 63349, United States

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Type locality. — “Habitat, nestling or burrowing in
Haliotis rufescens, at Monterey, also dead on beach, Dall;
nestling under stones at low water, Canfield, Stearns,
and Cooper.”

Range. — Middle Pliocene to Recent. Recent from
Monterey, California, to San Geronimo Island, near
Rosario Bay, Lower California, Mexico, from the inter-
tidal zone to a depth of 27 meters (15 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305.

Original description. — Shell minute, trapeziform,
white, with a thin brownish epidermis. Umbones prom-
inent, nearly terminal. Anterior margin rather strongly
angulated; basal margin straight, or a little concave; lower
posterior extremity angulated; upper posterior angle
rounded off; posterior margin rather oblique. Hinge line
smooth, rather broad. Ligament conspicuous, moderately
long. A rounded carina passes from the umbo to the
lower posterior angle, above which are from two to five
radiating ribs. General sculpture of sharp elevated lines of
growth, which become vaulted scales on the ribs. Margin
lightly crenulated. Interior polished; muscular and
pallial impressions indistinct. Long. 14, lat. .08, alt.
.175 in. (Dall.)

Remarks. — Three valves of this species are present in
the collection from Loc. 305 (LAM). One of these, a well
preserved right valve, is 5 mm long.

This is the first record of Milneria minima in beds
of Pliocene age but it was reported by Vedder (640) from
a terrace of Pleistocene age on San Nicolas Island, Cali-
fornia.

Woodring reported the occurrence of Milneria
kelseyi Dall (641) from beds of Pleistocene age in the
Palos Verdes Hills, San Pedro, as did Chace, 1966, and
Vedder (1960) reported ‘“‘Milneria cf. M. kelseyi” from
strata of Pliocene age in the Los Angeles basin, California.
That species in some cases has been confused with M.
minima. The major radial ribs on M. minima are rather
coarse and are about equal in size, whereas those on M.
kelseyi are finer and less coarsely scaled. The umbonal
and one or more of the other ribs, are higher than the rest.
Furthermore the lunule of M. kelseyi is smaller and the
escutcheon larger than that of M. minima. Milneria
kelseyi attains a greater size than M. minima, up to 8 mm
long, and is said to be the one more commonly found
under rocks along the seashore.

SUPERFAMILY LEPTONACEA GRAY (642)

Remarks. — Most of the members of this superfamily
possess small, thin shells, and often nestle in crevices, in
holes in rocks, or in empty shells, Such habitat often
results in distortion and variability in shape of the shells.
Some forms live symbiotic with other invertebrates such
as echinoderms, sponges, and crustacea. The exact
relationships of the members of this superfamily are
unknown.

Dall (643) published a synopsis of the Recent and
Tertiary Leptonacea of North America and Laseron (644)
recently presented a revision of the Leptonidae of New
South Wales, Australia.

Some authors have included this group of mollusks
under the Erycinacea and Erycinidae (645). However,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Swainson (646) in 1832-1833 used the family name
Erycinidae in the phylum Insecta. Later Wood (647)
included many of the genera of these small mollusks in
the Fragillidae. Until the higher categories of molluscan
nomenclature are more stabilized, it seems best to include
this group under the well known superfamily name Lep-
tonacea.

Chavan (648) recently discussed the hinge characters
of the superfamily “‘Erycinacea.”” He placed the following
six families under this category: Erycinidae, Kelliidae,
Leptonidae, Montacutidae, Galeommatidae, Kelleyellidae.

A paper by Popham (649) contains the results of a
study of the mantle cavities of some members of this
superfamily, and a publication by Oldfield (650) deals
with their reproduction and development. Boss (651)
recently discussed the symbiotic habits of this group of
small bivalves.

In the present paper we have assigned as members
of the Leptonacea, the families Kelliidae and Monta-
cutidae. Clark, the author of those families considered
the well known genus Lepton Turton (652) to be quite
distinct from the genera included in those groups.

FAMILY KELLIIDAE FORBES AND HANLEY (653)

Shell small, ovate or obicular, thin, convex, white
or subtranslucent, the umbones and beaks submedian or
anterior. Surface smooth and often glossy, occasionally
punctate or partially radially ribbed; external ligament
small, the internal resilium attached to a_ posteriorly
directed oblique groove; hinge with one or two cardinal
teeth and, usually one or two posterior lateral teeth in
each valve, but lacking in some genera; pallial line simple;
surface of exterior sometimes covered by the mantle.
(Adapted in greater part from Olsson, Mollusks of the
Tropical Eastern Pacific, Paleo. Res. Inst.: Ithaca, New
York, p. 231, 1961.) Paleocene to Recent.

GENUS ALIGENA LEA

Aligena H. C. Lea, Proc. Amer. Philos. Soe., Vol. 3, p. 163
September, 1843. Aligena striata and A. laevis men-
tioned but without description or illustration. — H. C.
Lea, Trans. Amer. Philos. Soc., New Ser., Vol. 9, p.
238, December, 1846. Aligena striata and A. laevis
described and illustrated. — Dall, Trans. Wagner Free
InstaSceit, Vola.35 Pt: 5, ps 11175, 1900. “Type; A.

235

striata Lea.”’ — Gardner, U.S. G. S., Prof. Paper 199A,
p. 87, 1943. Type as designated by Dall. — Harry,
Veliger, Vol. 11, No. 3, p. 164, 1969. Earlier designa-
tions cited.

Type species (by subsequent designation, Dall, Trans.
Wagner Free Inst. Sci., Vol. 3, Pt. 5, p. 1175, 1900). —
Aligena striata H. C. Lea, Trans. Amer. Philos. Soc., Ser. 2,
Vol. 9, p. 238, pl. 34, fig. 13, December, 1846. “From
the Tertiary of Petersburg, Virginia.’ Dall (Proc. U. S.
Nat. Mus., Vol. 21, No. 1177, p. 877, 1899) cited Abra
aequata Conrad as the “‘typical species” of Aligena but
that species was not included with the taxa originally
referred to Aligena by Lea. Later, Dall placed Aligena
striata Lea in the synonymy of Aligena aequata (= Amphi-
desma aequata Conrad, 1843). See Dall, 1900, p. 1175,
pl. 24, figs. 8, 8a, 8b. Miocene of southeast Atlantic
states, also Caloosahatchie Pliocene of Florida.

Range. — Miocene to Recent. Recent in temperate
and tropical waters, usually from low tidal zone to 112
meters (61 fathoms). One species was reported by Dall
from 3680 meters (2012 fathoms).

Description. — The characteristic of this group is the
possession of a rounded triangular inflated shell with only
a single small anterior tooth under the beaks, separated
by a gap from the surface of attachment, under the
posterior dorsal margin, of an elongate internal resilium
carrying a lithodesma. The pallial line is simple, and the
cardinal of the left valve more feeble than the other.
(Dall, 1900.)

Remarks. — Aligena is here recorded for the first
time from beds of Pliocene age in the west American
states. This genus is well known in beds of Miocene age in
the Atlantic states and has been reported from the Vienna
and Paris basins.

Four Recent species referable to Aligena have been
described from west American waters two of which have
been reported from beds of Pleistocene age.

Dall (1900, p. 1175) believed that a close relation-
ship existed between Aligena and Spaniodon Reuss (654),
but Cossmann and Peyrot (655) believed it to be close to
Spaniorinus Dall (656).

Harry (657) recently reviewed the living species of
Aligena. He mentioned that some species of this genus
are probably polychaete associates.

Aligena diegoana n. sp.
Plate 44, Figures 1, 6;
Plate 45, Figures 6, 7, 10, 11, 13

Description. — Shell roundly quadrangular, rather
large for the genus, convex, the anterior is longer and

Key to Genera and Subgenera of Kelliidae

A. Left valve with 1 cardinal tooth;

lateral teeth lacking . Aligena
B. Left valve with 2 cardinal teeth;
lateral teeth present
a. Valves smooth; periostracum
present Kellia

aa. Valves radiately striated or
punctate; periostracum lacking

b. Ventral margin of hinge plate
bisected by the resilum . . Bornia
bb.Ventral margin of hinge plate
not bisected by the resilium. . Temblornia

236

narrower than the posterior end; beaks small, prosogyrate,
situated a little posterior to the middle of the valves;
lunular area gently depressed; anterior dorsal margin
sloping moderately steeply to the anterior and which is
rounded and slightly attenuated, posterior dorsal margin
sloping gently downward and merging imperceptibly into
the broadly rounded posterior end, ventral margin very
slightly rounded; exterior of valves sculptured only with
lines of growth; hinge of right valve with a large, slightly
twisted tooth beneath the beak, behind this a subtriangu-
lar, elongated ligamental pit; in front of the tooth there
is an elongated depression which receives a projection of
the opposite valve and fades out as a slight groove along
the margin; hinge of left valve (paratype) with a large,
tooth-like projection of the lunular margin, behind this
a very small cardinal lamella (lacking on some specimens)
below the beak, and back of this the ligamental pit. Di-
mensions of holotype, a right valve, length 7.9 mm, height
6.1 mm, convexity (one valve), (approximately) 2 mm.

Type Specimen. — Holotype and paratypes in Los
Angeles County Museum. From Loc. 305 (LAM), 2400
feet east and 1350 feet south of the northwest corner of
Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridi-
an (see U. S. G. S. topog. map, San Ysidro quad., ed.
1943).

Occurrence in San Diego Fm. — L.A.M. 305A, 318,

319.
Remarks. — This species is represented in the present

collections by more than 30 single valves. These vary in
outline, some are more rounded in outline than others, and
in some specimens the ventral margin is nearly straight. A
broad, low, medial sulcus is present on some valves.

The cardinal tooth in the left valve of A. diegoana,
n. sp., is reduced to a thin lamella, or is absent on some
specimens. The development of a tooth-like projection of
the lunular margin which fits into a groove on the opposite
valve appears to be compensatory for the reduction of
the cardinal and augments the interlocking of the hinge
area.

The general outline of Aligena diegoana, n. sp., is
somewhat similar to that shown in an illustration of a
Recent specimen from off the west coast of Lower Cali-
fornia which Harry (1969, fig. 16) referred to Aligena
cerritensis Arnold. The type specimen of A. cerritensis is
obliquely ovoid in outline.

The general shape of some valves of the new species
is similar to that of Aligena aequata var. nuda Dall from
Miocene strata in Maryland, as illustrated by Glen (658).
The new species also bears a resemblance to the east
American Aligena laevis H. C. Lea (659) which occurs in
strata of Miocene and Pliocene age. The west American
species is more quadrate in outline and the hinge of the
right valve apparently has a deeper, more trigonal liga-
mental pit.

The species described as Aligena redondoensis by T.
Burch (660) was placed by Harry (1969, p. 179, figs. 34-
37) in a new genus Tomburchus and assigned to the
family Thyasiridae.

A species from British Columbia was described as
Aligena (Odontogena) borealis by Cowan (661). This
boreal species is the type of Odontogena to which Harry
(1969, p. 179) assigned generic rank.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

GENUS KELLIA TURTON

Kellia Turton, Conchylia Insularum Britannicarum, pp.
XIX, XXV, 56, 1822. Species cited, Kellia suborbicu-
laris Montagu, Cardium rubrum Montagu and Cardium
laeve Walker (in synon.) — Jeffreys, Brit. Conch., Vol.
2, p. 222, 1863. — Kobelt, Ilustr. Conchylienbuch, Bd.
2, Lief, 10-11, p. 351, 1881. “‘Typus is Kellia subor-
bicularis Montagu (Taf. 103, Fig. 3) aus den europaischen
Meeren.” — K. V. W. Palmer, Geol. Soc. Amer., Mem.
76, p. 87, 1958. “‘Type species by subsequent designa-
tion, Recliz’’. . ., 1844. — Olsson, Mollusks of the
Tropical Eastern Pacific, (Paleo. Res. Inst., Ithaca, New
York), p. 231, 1961. Type species as designated by
Recliz.

Chironia Deshayes, Rev. Zool. par la Soc. Cuvierienne,
Ann. 1839, p. 357. Sole species, ““Chironia Laperousii.”

Kellyia Turton (emend.), Bucquoy, Dautzenberg, and
Dollfus, Moll. Mar. du Roussillon, Tome 2, Fase. 6
(Pelecypoda, Fasc. 19), p. 235, 1892. “Il faut done que
le Mya suborbicularis soit conserve comme type du
genre Kellyia.”

Kellya Turton, Thiele, Handbuch Syst. Weichtierkunde,
Bd. 2, p. 870, 1934. [Not all the synonymy. ]

Type species (by subsequent designation, Recluz,
Rev. Zool., Soc. Cuvierienne, Vol. 7, p. 295, 1844). — “Le
type de son Kellia, celui seul qui correspond au caractere
de son genre, le Kellia suborbicularis . . .” [ = Mya
suborbicularis Montagu, Test. Britannica, Pt. 1, p. 39,
1803. ‘‘We first discovered this species in hard limestone
at Plymouth.” “It is sometimes dredged up in Saleomb-
bay.” Illustrated in Suppl., pl. 26, fig. 6, 1808. — Turton,
Conch. Ins. Brit., p. 57, p. 11, figs. 5, 6, 1822 (as Kellia
suborbicularis). ‘In limestone and old _ bivalves.” —
Forbes and Hanley, Hist. Brit. Moll., Vol. 1, pl. 0, fig. 4
(animal), 1853; Vol. 2, p. 87, pl. 18, figs. 9, 9a, 9b, 1853
(as Kellia suborbicularis). Loire basin, France, middle
Miocene. — Tebble, British Bivalve Seashells [British
Museum (Nat. Hist.)]. p. 83, text fig. 37a, b, c, 1966 (as
Kellia suborbicularis. )

Range. — Eocene to Recent. Recent, widespread in
all seas from intertidal zone to 2772 meters (1515
fathoms).

Description. — Shell small or of medium size, thin,
glassy, white, suborbicular and strongly convex, surface
usually smooth, polished or with fine or strong, concentric
lines of growth. The umbones are prominent, submedian,
the small beaks incurved and prosogyrous. Hinge plate
narrow, with a wide notch in the middle bordered on each
side by a small tooth, the anterior one shaped like a car-
dinal tooth, the posterior one placed more distantly; the
left valve has two small divergent cardinal teeth with a
socket or pit between them, the right valve has a single
cardinal only; both valves have a flattened tooth at the
posterior end of the median pit. Ligament is wholly in-
ternal, the tensilium small, narrow, lying below the margin
and above a narrow nymphal lamina which distantly ends
in a tooth, the resilium also elongated in form and at-
tached to a linear groove in the roof of the subumbonal
cavity. In some species, the surface is covered by a glossy,
yellowish periostracum. (Olsson, Mollusks of the Tropical
Eastern Pacific. Paleo. Res. Inst.: Ithaca, New York,
p. 231, 1961.)

Remarks. — There have been differences of opinion

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

by various authors (662) concerning the spelling of this
generic name but most authors adhere to the original
orthography, Kellia.

The members of Kellia often nestle in holes in rock
or in pilings. Some species attain a length of 33 mm (663)
but most of them are shorter. Oldfield (664) discussed
the functional morphology of K. suborbicularis.

In western North America, three species referred to
Kellia have been described from beds of Eocene age, one
in the Oligocene, and two range from Pliocene to Recent.
The genus is here reported from the San Diego Formation
for the first time.

Kellia laperousii Deshayes
Plate 44, Figures 11, 19

Chironia laperousii Deshayes, Rev. Zool., Soc.Cuvierienne,
Annee 1839, p. 357, issued December, 1839. —
Deshayes, Mag. de Zool., Ann. 1840, Livr. 5, Moll., pl.
12, 4 figs. — Chenu, Man. de Conchyl., Vol. 2, p. 126,
figs. 600, 601, 1862.

Bornia luticola Valenciennes, Voy. Venus, Atlas,Moll., pl.
24, figs. 7, 7a, 7b, 1846. [No description nor locality. }

Kellia laperousii Deshayes, Carpenter, Rept. Brit. Assoc.
Adv. Sci. for 1863, p. 643, issued August, 1864. Cited
from several localities from Vancouver Island, British
Columbia, to California. Reprint in Smithsonian Misc.
Coll., No. 252, p. 129, 1872. — Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 137, pl. 18, figs. 1, la, 1903.
Pliocene to Recent. San Pedro and San Diego, Cali-
fornia, Pleistocene. — I. S. Oldroyd, Publ. Puget Sound
Biol. Sta., Vol. 4, p. 39, pl. 6, fig. 2; pl. 37, fig. 4, 1924.
“Bering and Pribilof Islands, Bering Sea, to San Diego,
Calif.” — Yonge, Univ. Calif. Publ. Zool., Vol. 55,
No. 11, pp. 451-453, fig. 1 (in text), 1951. — Morris,
A Field Guide to Shells of the Pacific Coast and
Hawaii. (Houghton Mifflin Co., Boston) p. 38, pl. 10,
fig. 7, 1952. — Howard, Wasmann Jour. Biol., Vol. 11,
No. 2, p. 238, fig. 3 (p. 237), 1953.

Kellya laperousei Deshayes, Fischer, Man. de Conchyl.,
Fasc. 11, p. 1026, pl. 19, fig. 11 (“Californie”), 1887.

Kellia laperousei Deshayes, I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 131, pl. 10, fig. 2;
pl.33, fig. 4, 1924. “Bering Sea and Pribiloff Islands to
San Diego, California.” Also San Pedro, Pliocene; and
San Pedro and San Diego, California, Pleistocene.

Chironia suborbicularis (Montagu) variety laperousii
Deshayes, Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 300, pl. 14, figs. 19a, 19b, 1931.
[Not all the synonymy.] Pleistocene and Recent.

Type specimen. — Dr. André Franc informed us
(written communication, October 22, 1964) that two
valves labeled “‘Type”’ are in the collection of the La-
boratoire de Malacologie, Museum National d’Histoire
Naturelle (Paris) but that it is uncertain whether or not
these represent the type specimen.

Type locality. — No locality cited originally.

Range. — Middle Pliocene to Recent. Recent from
Bering Sea and Pribilof Islands to Tiburon Island in the
Gulf of California, from intertidal zone to 393 meters
(215 fathoms).

Occurrence in San Diego Fm. — L.A.M. 107, 305,
305A.

237

Original description. — Testa ovato transversa, sub-
equilaterali, inflato turgida, laevigata; alba sub-epidermide
viridi lutescente, umbonibus minimis, acutis, oppositis.
(Deshayes.)

Remarks. — Several valves here referred to Kellia
laperousii are present in the collections of the Los Angeles
County Museum from near the Mexican boundary. One of
the largest of these is 8.5 mm long and 6.9 mm high.
One very convex right valve from Loc. 107 (LAM), re-
taining most of the shell material, apparently the same
species, is 17 mm long, 13.5 mm high, convexity, ap-
proximately 5 mm. These valves closely resemble Recent
specimens, in various collections, identified with K.
laperousii. A large Recent specimen in the collections of
the California Academy of Sciences, collected by W. W.
Schneeble in Monterey Bay, California, at a depth of 40
feet, is 31 mm long, 25 mm high, the convexity (both
valves together) 29 mm.

This is the first record of the occurrence of this
species in the San Diego Formation. It has been reported
from beds of similar age, the Cebada Member of the
Careaga Formation, in the Santa Maria district in Santa
Barbara Co.

Some of the small valves, about 3 mm long, from
near the Mexican boundary, bear a close resemblance to
K. suborbicularis Montagu, originally described from
England. However, there is so much variation in shape in
a series of Recent specimens of K. laperousii, some
elongated, some subcircular, that we assign all the fossil
valves in the present collections to that species. Howard
(1953) discussed the early stages of development of this
species.

Kellia suborbicularis Montagu (665), reported to
range from middle Miocene to Recent in Europe, has been
reported from beds of Pliocene age in Los Angeles by
Soper and Grant (666), by others from beds of Pleistocene
age in southern California and in the Galapagos Islands.
It was cited by Laws (667) as occurring in beds of Pleis-
tocene age in New Zealand, and from beds of Pleistocene
age from widespread areas such as Morocco, Patagonia and
New Zealand. It has been reported living in nearly all
temperate and tropical seas. Some authors have con-
sidered it to be a bipolar species. Marie Lebour discussed
the life history of this species (see Jour. Mar. Biol. Assoc.
U. K., Vol. 22, No. 2, pp. 447-451, text-fig. 1 (a-h, j-m),
1938).

The question as to whether this species is cosmo-
politan or whether several closely related forms are
involved has been discussed -by several authors. E. A.
Smith (668) stated that shells of this species could not be
separated with certainty from allied forms. More
recently Soot-Ryen (669), in a discussion of Antarctic
shells similar to K. suborbicularis, stated that the relation-
ship of such forms is still unsettled but he suggested that
probably a number of nearly related species are con-
cerned in this problem.

None of the fossils from the San Diego Formation
is as circular in outline as the syntypes of the Recent west
American K. laperousii chironii Carpenter illustrated by
Palmer (670).

Kellia rotunda Carpenter was described as much
larger than K. suborbicularis and nearly round in outline.
The type of this species was not found by Palmer (671) and
it generally has not been cited in recent years.

238

GENUS BORNIA PHILIPPI

Bornia Philippi, Enumeratio Molluscorum Siciliae, Vol. 1,
p. 13, 1836. — Gardner, U.S. G. S., Prof. Paper 199-A,
p. 82, 1943 [January, 1944]. Type as designated by
Stoliczka. — Olsson and Harbison, Acad. Nat. Sci.
Philadelphia, Monogr. No. 8, p. 92, 1953. Type as
designated by Stoliczka.

Type species (designated by Stoliczka, Mem. Geol.
Surv. India, Paleo. Indica, Ser. 6, Vol. 3, Cretaceous
Fauna of South India, Vol. 3, pp. XIX, 266, 1870).—
“type, B. corbuloides, Phil.’ [Bornia corbuloides Philippi,
1836, p. 14, pl. 1, fig. 15. ‘Habitat Cataniae, Panormi,
non rara.’”’ — Bucquoy, Dautzenberg, and Dollfus, Moll.
Mar. Roussillon, Vol. 2, Fase. 6 (Pelecypoda, Fase. 19),
p. 235, pl. 39, figs. 1, 2, 1892 (as Kellyia sebetia Costa;
as of Cantraine on expl. to plate). Mediterranean and
Adriatic; Portugal. Miocene to Recent. — Cossmann and
Peyrot, Conch. Néogéne |’Aquitaine, Vol. 1, Livr. 3 (extr.
from Act. Soc. Linn. Bordeaux, Vol. 65), p. 569, fig. 109
(hinge of Bornia sebetia), 1911.]

Range. — Early Eocene to Recent.

Description. — Shell usually small, subtrigonal to
subelliptical, compressed or weakly convex. Surface usually
smooth, polished or faintly ribbed and striated. Ligament
comprising a feeble external portion, more or less
amphidetic and a subumbonal, internal resilium without a
lithodesma. Hinge: left valve with a long, strong, post-
erior lateral tooth and a smaller, less distant anterior
lateral, together with a small cardinal closely adjacent to
it;in the right valve with strong lateral sockets and a small,
anterior cardinal socket. (Olsson and Harbison.) —_,

Remarks. — The shell of this genus differs from
that of Kellia in that the surface is radially striate or
punctate, at least in part, in lacking a periostracum, and in
the narrower hinge in which the posterior cardinal of the
left valve is greatly reduced in size.

Five Recent species assigned to Bornia have been
described from the Panamic region and one from southern
California.

SUBGENUS TEMBLORNIA KEEN

Temblornia Keen, Trans. San Diego Soc. Nat. Hist., Vol.
10, No. 2, p. 38, December 30, 1943.

Type species. — “Type: Donax triangulata Ander-
son and Martin, 1914.” [Proc. Calif. Acad. Sci., Ser. 4,
Vol. 4, p. 63, pl. 3, fig. 9, December 30,1914 “...on
west bank of a small canyon 1 1/4 miles northeast of
Barker’s ranch house, Kern County, California.” Miocene.
— Keen, 1943, p. 39, pl. 3, figs. 6, 7 (as Bornia (Tem-
blornia) triangulata).

Range. — Middle Miocene to middle Pliocene.

Description. — Resembling Bornia in outline, with
radial sculpture on anterior and posterior slopes; differing
from Bornia, sensu stricto, in the structure of the hinge;
resilifer small and shallow, ventral margin of hinge plate
entire, not bisected as in Bornia, s. s., by the insertion of
the resilium; hinge teeth well developed, consisting of
two cardinals and a posterior lateral in the left valve, two
cardinals in the right. (Keen.)

Remarks. — Keen called attention to the similarity
of this subgenus to Semeloidea Bartram and Powell, which
has as type S. donaciformis Bartram and Powell (Trans.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

New Zealand Inst., Vol. 59, Pt. 1, p. 158, pl. 29, figs.
49, 50, 1928) from “Kaawa Creek, New Zealand, late
Tertiary.”

Compared to Semeloidea, the lower margin of the
hinge plate of Temblornia is more arched, the posterior
cardinal is less curved and the radial riblets, externally,
are more numerous and finer.

Three species of this subgenus have been reported,
the type species from strata of middle Miocene age in
California, one of Miocene age in Ecuador (672) and one
as yet undescribed species in the Gatun Formation of
Miocene age in the Panama Canal Zone. To these we add
a new species from the San Diego Pliocene.

Bornia (Temblornia) frankiana n. sp.
Text Figure 11

Description. — Shell, a right valve, small, elongately
trigonal, moderately inflated, nearly equilateral, slightly
longer posteriorly; anterior and posterior margins nearly
straight, near the ends rounding into the ventral margin;
10 rounded radial ribs on the anterior end just posterior
to the margin and 7 similar ones, somewhat flattened, on
the posterior end, the ribs are faint dorsally but become
gradually more strongly developed toward the ventral
margin; ribs separated by interspaces which are a little
wider than the ribs and in these, toward the ventral mar-
gin, lines of growth are accentuated (perhaps a result of
erosion); remainder of the valve smooth except for some-
what irregular lines of growth; hinge with 2 well developed
cardinal teeth; interior of anterior and posterior ends of
valve crenulated and slightly denticulated corresponding
to the exterior sculpture. Length 6.5 mm, height 4.1 mm.

Text Fig. 11. Bornia (Temblornia) frankiana Hertlein and
Grant, new species. Holotype (Los Angeles County
Museum), right valve from Loc. 305C (LAM), near the
Mexican boundary, southwestern San Diego County;
Pliocene. Length 6.5 mm. A. View of exterior. B. View
of interior. (Drawn by Dorothy Ludlow.)

Type specimen. — Holotype, a right valve, Inverte-
brate Paleontology Collection, Los Angeles County
Museum.

Type locality.—Loc. 305C (LAM), exposure at base
of hill, 100 feet west and 440 feet south of the northeast
corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

and Meridian (see U. S. G. S. topog. Map, San Ysidro
quad., rev. 1953.) San Diego Formation, middle Pliocene.

Range. — Known only from the type locality.

Remarks. — Bornia (Temblornia) frankiana, new
species, differs from the two other described species of
Temblornia in its more elongately trigonal outline and in
the nearly straight anterior and posterior margins.

This species is named for the late Frank Stephens,
Curator Emeritus, San Diego Society of Natural History,
who aided us on many occasions during field collecting in
the San Diego area.

FAMILY MONTACUTIDAE CLARK (673)

Shell generally small, ovate to oblong, thin or heavy,
depressed or convex, the anterior side the longer. Liga-
ment mostly internal, subumbonal or lodged in an elong-
ated, oblique resilifer in the hinge margin behind the beaks.
Surface smooth or with concentric growth lines and some-
times radial undulations. Habit of most species appears to
be commensal. (Olsson, Mollusks of the Tropical Eastern
Pacific, Paleo. Res. Inst.: Ithaca, New York; p. 233)
1961.) Eocene to Recent.

Key to Genera of Montacutidae

A. Right valve with 2 cardinal teeth. . Pristes

B. Right valve lacking cardinal teeth . .Mysella

GENUS MYSELLA ANGAS

Mysella Angas, Proc. Zool. Soc. London for 1877, p. 176,
issued August, 1877. Sole species: Mysella anomala
Angas. — Cotton and Godfrey, The Molluses of South
Australia (issued by the South Australian Branch of the
British Science Guild: Adelaide), p. 224, 1938.
“Genotype — M. anomala Angas.” — Olsson, Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 233, 1961. “Type species by
monotypy, M. anomala Angas. Australian waters.”

Rochefortia Velain, Compt. Rend. Acad. Sci. (Paris), Vol.
83, p. 285, July 24, 1876. Rochefortia australis, a
nomen nudum. — Velain, Arch. Zool. Exper. Gen.
(Paris), Vol. 6, p. 132, no earlier than November 12,
1877. — J. Q. Burch, (ed.), Min. Conch. Club South.
California, No. 110 p. 1, June, 1951. — see K. V. W.
Palmer, Geol. Soc. Amer., Mem. 76, p. 88, footnote
36, 1958. — Keen, Treatise on Invertebrate Paleon-
tology (Geol. Soc. Amer. and Univ. Kansas Press),
Pt. N. Moll. 6, p. N531, 1969. Type: R. australis
Velain, figs. 3a, 3b. Saint Paul Island, Recent.

Type species (by monotypy). — Mysella anomala

Angas [Proc. Zool. Soc. London for 1877, p: 176;

August, 1877. ‘Hab. Shark Island, Port Jackson, in black

mud, in 12 fathoms.” — Laseron, Rec. Australian Mus.,

Vol. 24, No. 2, p. 18, figs. 23, 23a, 23b, 1956. New

South Wales, Australia. — Keen, 1969, figs. 9a, 9b.]

Range. — Middle Miocene to Recent. Widely dis-
tributed in present seas, from 11 to 320 meters (to

175 fathoms).

Description. — Shell triangularly ovate, anterior end
longer, sculpture concentric; left valve with a large,
diverging, flattened tooth posterior to the triangular

239

resilifer; the anterior margin of the resilifer is thickened
and margined to simulate a transverse tooth; in front of
this is a small socket; right valve with the hinge margin on
each side of the umbo produced, which is overlapped by
the hinge line of the opposite valve; the posterior tooth-
like edge interlocks above the cardinal tooth of the left
valve, and the anterior which is shorter, is received in the
socket in front of the ridge-like edge of the resilifer.
These tooth-like margins of the right valve represent cardi-
nal rather than lateral teeth. (Cotton and Godfrey.)

Remarks. — Laseron (1956, p. 18) pointed out that
a feature common to all species of Mysella “‘is that the
horizontal lateral processes in the right valve are caused by
a peculiar infolding of the dorsal margin on either side of
the umbos, and are in no sense lateral teeth as generally
understood.”

Fossil and Recent species attributed to this genus
have been recorded from various regions. The genus has
been reported from Pliocene to Recent in western United
States. About 12 species referred to ‘“Rochefortia” or
Mysella have been reported living in west American waters
between the Aleutian Islands, Alaska, and the Gulf of
California, and others have been described from more
southern waters.

Some authors treat Mysella and Rochefortia (674) as
separate genera. Others place Rochefortia either as a
subgenus of Mysella or in the synonymy of that genus.

The species of small bivalves belonging to Mysella
and related genera, will remain difficult to identify speci-
fically until careful comparative studies are made and
adequate illustrations are available.

Dell (675) discussed some of the Antarctic and
subantarctie species of Mysella.

Mysella tumida Carpenter
Plate 44, Figures 2, 3, 4, 5, 7, 8, 12;
Plate 45, Figures 5, 8, 9, 12

Tellimya tumida Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, pp. 602, 611, 643, August, 1864. Reprint
in Smithsonian Mise. Coll., No. 252, pp. 88, 97, 129,
1872.

Mysella tumida Carpenter, Dall, Proc. U. S. Nat. Mus.,
Vol. 21, No. 1177, pp. 881, 892, pl. 87, fig. 7 (“type
specimen.” ‘‘California.”), 1899. ‘‘Alaska Peninsula
and south to San Diego, California,” Recent. — Abbott,
Amer. Seashells (D. Van Nostrand Co.), p. 397, fig.
80b, 1954. “Alaska to Lower California.”” — K. V. W.
Palmer, Geol. Soc. Amer., Mem. 76, p: 88; pll 7:
figs. 8-12, 1958. LEarlier records cited.

Rochefortia tumida Carpenter, Dall, U. S. Nat. Mus.,
Bull. 112, p. 37, 1921. “Shumagin Islands, Alaska, to
San Diego, California.” — I. S. Oldroyd, Publ. Puget
Sound Biol. Sta., Vol. 4, p. 40, 1924. “Orcas and Turn
Islands, Wash., along shore.” Shumagin Islands,
Alaska, to San Diego, California. — I. S. Oldroyd, Stan-
ford Univ. Publ. Univ. Ser. Geol. Sell, Vol: 15 p: 132)
pl. 54, figs. 11-14, 1924. Same range as in preceding
reference.

Type specimen. — No. 5242, United States National

Museum.

Type locality. — Indicated as from Puget Sound and
the neighborhood; Vancouver Island, Straits of San Juan
de Fuca, and adjoining shores of Washington territory;

240

also the region between San Diego and San Pedro, Cali-
fornia. “The holotype bears the label ‘Puget Sound, Ken-
nerley’ ” (Palmer, 1958.)

Range. — Middle Pliocene to Recent. Recent from
the Shumagin Islands, Alaska, to Scammon Lagoon, Lower
California, Mexico, shore to 88 meters (48 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A,
318.

Original description. — “Between bidentata and
substriata: ossicle minute.” (Carpenter, 1864.)

Supplementary description. — T. t. subtriangulari,
subovata, laevi, solidiore, tumidiore, valde inaequilaterali;
cinerea, epidermide pallide olivacea, concentrice striata
induta; marginibus dorsalibus subrectis, ventrali excurvato:
intus, dentibus cardinalibus valva sinistra validissimis,
curtis, extantibus, postico longiore, valva dextra callositat-
ibus marginalibus, dentibus nullis; cartilagine validiore,
ossiculum parvum in medio gerente; cicatricibus adductor-
ibus a cardine valde remotis. Long. .115, lat. .125, alt. .06.
(Carpenter, Proc. Acad. Nat. Sci. Philadelphia, Vol. 17,
p. 58, 1865.)

Remarks. — Many valves here referred to Mysella
tumida are present in the collections from near the
Mexican boundary. These are small, the largest about 3mm
long, rounded trigonal to trigonally ovate and gently con-
vex. The left valve, as mentioned by Palmer, has two
cardinal teeth which are quite large for the size of the
shell.

This is the first record of the occurrence of this
species in the San Diego Formation. Woodring (676) re-
ported it from the Graciosa Member of the Careaga Sand-
stone in the Santa Maria district in beds of late Pliocene
age.

The fossils from San. Diego are quite similar to
specimens from Puget Sound in the collections of the
California Academy of Sciences which were identified by
T. S. Oldroyd as ‘“Rochefortia” tumida. Some of the
specimens in the present collection are more elongate than
others. Similar forms were illustrated by Addicott (U. S.
G. S., Prof. Paper 523-C, p. C4, pl. 4, figs. 12, 13, 1966)
under the name of ‘‘Mysella cf. M. tumens” from beds of
Pleistocene age at Point Ano Nuevo, San Mateo Co.,
California.

The species described by Dall as Mysella pedroana
(677) is elongate in outline but the hinge was described
as “feeble.” The illustration of the type shows the hinge
to be quite different from that of M. tumida. Another
elongate species, was described but not illustrated, under
the name of Rochefortia golischi Dall (678). MacGinitie
(679) discussed the shell characters of M. pedrona and M.
golischi and stated that the two are distinct species. She
mentioned that on M. pedroana the umbones are nearer
the anterior end and that the posterior end (more elong-
ated than the anterior end) slopes more abruptly down-
ward than that of M. golischi.

GENUS PRISTES CARPENTER

Pristes Carpenter, Rept. Brit. Assoc. Adv. Sci. for 1863,
pp. 611, 643, issued August, 1864. Reprint in Smith-
sonian Misc. Coll., No. 252, pp. 97, 129, 1872. Sole
species Pristes oblongus Carpenter. — Vokes, Jour.
Paleo., Vol. 30, No. 3, p. 768, May, 1956. — K. V. W.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Palmer, Geol. Soc. Amer., Mem. 76, p. 89, 1958. “Type
species by monotypy Pristes oblongus Carpenter.”

Not Pristis Linck, 1790. Not Pristis Muller and Henle,
1837.

Pristiphora Carpenter, Proc. Calif. Acad. Nat. Sci., Vol. 3,
p. 210, February, 1866.

Not Pristiphora Latreille, 1810. Hymenoptera.

Serridens Dall, Proc. U. S. Nat. Mus., Vol. 21, No. 1177,
p. 880, June, 1899. A new name for Pristiphora
Carpenter, 1866. Not Pristiphora Blanchard, 1835.
Type species (by monotypy). — Pristes oblongus

Carpenter.

Range. — Middle Pliocene to Recent. Recent, inter-
tidal, commensal with [schnochiton.

Description. — Shell oval, with two diverging teeth
in each valve, the anterior being conspicuously shorter
than the posterior, suleated near the beaks, ligament
situated in a groove between them. (Tryon, G. W., Jr.,
Structural and Systematic Conchology, Vol. 3, p. 220,
1884.)

Remarks. — This genus of small leptonids is repre-
sented solely by the type species which lives only in
eastern Pacific waters. Vokes (1956), and K. V. W.
Palmer (1958), discussed the nomenclatorial problems
concerning the genus name Pristes. This genus is reported
here for the first time from beds of Pliocene age.

Pristes oblongus Carpenter
Plate 44, Figures 9, 10, 13, 14

Pristes oblongus Carpenter, Rept. Brit Assoc. Adv. Sci.
for 1863, pp. 611, 643, issued August, 1864. Reprint
in Smithsonian Misc. Coll., No. 252, pp. 97, 129, 1872.
P. 611 (97). “S. Diego.” P. 643 (129), “D” [=] “The
region between S. Diego and S. Pedro.” — K. V. W.
Palmer, Geol. Soc. Amer., Mem. 76, p. 89, pl. 9, figs.
11-13, 1958. “San Pedro to San Diego, California
[San Pedro] (type); Monterey, California to San
Hipolito Point, Lower California (Burch).”

Pristiphora oblonga Carpenter, Proc. Calif. Acad. Sci.,
Vol. 3, p. 210, February, 1866. ‘Hab. San Diego; 1
worn valve among shell washings. Cooper.”

Serridens oblonga Carpenter, Dall, Proc. U. S. Nat. Mus.,
Vol. 21, No. 1177, p. 880, 1889. ‘San Pedro, Cali-
fornia” — I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 135, pl. 54, figs. 5, 6, 7, 8,
1924. “Type locality, San Diego, California.” “Range:
Puget Sound to Coronado Islands, Lower California.”
— J. Q. Burch, Min. Conch. Club South. California,
No. 40, p. 16, October, 1944. Monterey, California,
to San Hipolito Point, Lower California. Commensal
with Ischnochiton conspicuus Carpenter, and I. mag-
dalenensis Hinds.

Type specimen. — Lectotype No. 15592, United
States National Museum (Palmer, 1958).

Type locality. — ‘“S. Diego” and “The region be-
tween San Diego and San Pedro,” Carpenter, 1864. San
Pedro, California, selected as type locality by Palmer
(1958).

Range. — Middle Pliocene to Recent. Recent from
Monterey, California, to San Hipolito Point, Lower Cali-
fomia, commensal with Jschnochiton conspicuus Carpenter,
I. heathiana Berry and I. magdalenensis Hinds.

Occurrence in San Diego Fm. — L.A.M. 305, 305A.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Original description. — “Like Tellimya, with long
marginal teeth, serrated near hinge.” (Carpenter, 1864.)

Supplementary description. — P. t. oblonga, parva,
subquadrata, valde inaequilaterali; parte antica fere nulla,
marginibus, dorsalibus subrectis, fere rectangulatis, ventrali
parum excurvato, postico rotundato; umbonibus antie
flectis; lunula parva, concava: intus, v. sinistr., dent. lat.
post. per totam longitudinem dorsalem decurrente, parte
cardinali acuta, alte transversim sulecata, ant. secundum
lenulam incurvato curto, serrato; cicatr. adduct. sub fines
dentium sitis. Long. 0.14, lat. 0.10, alt. 20.06. (Carpenter,
1866.)

Remarks. — Nine single valves of Pristes oblongus
are present in the collections from near the Mexican
boundary. This is the first record of its occurrence in the
San Diego Formation. Previously it was reported as a
fossil by Valentine (680) from beds of Pleistocene age at
Crown Point, San Diego, California.

This small, elongate leptonid was reported from
Puget Sound by I. S. Oldroyd, 1924, but later authors
have cited it as ranging northward only to Monterey, Cali-
fornia. It lives commensal with chitons.

FAMILY SPORTELLIDAE DALL (681)

Shells are generally small, ovate to narrowly
elongate, thin and usually white in color. The umbones
are usually prominent, sometimes near the middle,or much
closer to the anterior end. Hinge generally with one or two
large teeth in each valve. Ligament largely external,
occasionally showing a small, internal resilium. Surface
smooth or roughtened with growth threads, sometimes
heavily pustulated. (Olsson, Mollusks of the Tropical
Eastern Pacific, (Paleo. Res. Inst.: Ithaca, New York),
p. 241, 1961.) Late Jurassic (682) (Sequanian); Paleocene
to Recent.

GENUS BASTEROTIA MAYR IN HORNES

Harlea Gray, Synop. Brit. Mus., 1842, p. 78 [no species
cited]. See E. A. Smith, Proc. Zool. Soe. London,
April 1, 1890, p. 303.

Eucharis Recliz, Jour. de Conchyl., Vol. 1, p. 164, 1850.
Type, Corbula quadrata Hinds.

Not Eucharis Latreille, 1804.

Basterotia Mayr in Hornes, Verhandl. K. K. Zool.-Bot.
Gesell. Wien, Bd. 9, Abh. p. 71, 1859. Basterotia
corbuloides Hornes cited and illustrated. — Woodring,
Carnegie Inst. Washington, Publ. No. 366, p. 190,
1925. “Type (by monotypy). — Basterotia corbuloides
Mayer.” [The genus placed in the family Basterotidae. |
— Hertlein and Strong, Zoologica, Vol. 31, Pt. 4, p.
137, 1947. “Type (by monotypy): Basterotia corbu-
loides Hornes.’’ — Olsson Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 242, 1961. ‘“‘Type species by monotypy, Basterotia
corbuloides Hornes.”’

Not Basterotia Bayle in Jousseaume, 1884. Gastropoda.

Type species (by virtual monotypy.) — Basterotia
corbuloides Hornes, 1859, p. 71, three figs., ‘‘Wiener

Becken.”’ Miocene. See also Hérnes, Abhandl. K. K. Geol.

Reichsanst., Bd. 4, p. 40, pl. 3, figs. 1la-g, 1870. Various

localities cited in Vienna Basin, Austria. Miocene.

Range. — Miocene to Recent. Recent in the eastern

241

Pacific from the Gulf of California to Ecuador and the
Galapagos Islands. Also Caribbean and Indopacific; from
11 to 1170 meters (6 to 640 fathoms).

Description. — Shell small, subquadrate corbuliform,
with a sharp angle or carination running from the beak
posteriorly. Valves convex and usually solid, white, the
beaks prosogryate. Surface marked with fine concentric
lines of growth and a sprinkling of fine or coarse granules.
Ligament external, attached to a short,stout, plate-like
nymph. Hinge with a large, hook-shaped cardinal tooth
in each valve, bordered behind or in front by a deep
socket; in the right valve, the socket lies in front of the
tooth and in the left valve behind. There is no pallial
sinus. (Olsson, 1961, p. 242.)

Remarks. — Four species referred to this genus have
been reported from the late Cenozoic of the tropical
eastern Pacific, one of which is Recent.

Lamy (683) listed 13 Recent species which he
referred to Basterotia. Some of these were placed in
other genera by later workers.

SUBGENUS BASTEROTELLA
OLSSON AND HARBISON

Basterotella Olsson and Harbison, Acad. Nat. Sci. Phila-
delphia, Monogr. No. 8, p. 97, November 6, 1953.
Type species (by original designation and by mono-
typy). — Pleurodesma floridana Dall [Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 6, p. 1630, pl. 57, fig. 30, October,
1903. ‘Pliocene marls of Shell Creek, Florida; long. 14.5
mm.” See also Olsson and Harbison, 1953, p. 98, pl. 8,
fig. 2; pl. 9, figs. 1, la (as Basterotia (Basterotella)
floridana.) Florida, Pliocene].

Range. — Miocene to Recent. Recent in the
eastern Pacific from the Gulf of California to Ecuador and
the Galapagos Islands.

Description. — Like Basterotia in form, angled or
carinate umbo, surface granulation and large, hook-shaped,
subumbonal cardinal tooth, but differs in having both an
internal and external ligament. Nymphal plate small and
narrow, the resilial pit a small scar on its inner and lower
face. (Olsson and Harbison, 1953.)

Remarks. — The shell of the type species of Bastero-
tella bears scattered granules which are strongest near the
anterior-ventral side. These granules are said to be present
on the right valve of Caribbean members of this group,
but may be lacking on the left valve. No such granules
have been described as occurring on the valves of west
American species assigned to this subgenus.

Four species described from the tropical and sub-
tropical eastern Pacific have been assigned to Basterotella.
Three species described from the Gulf of California region,
have been reported as follows: one from strata of late
Pliocene age, two from the Pleistocene and one of these
Recent. An additional species living in Ecuador and the
Galapagos Islands was described by Olsson.

This is the first record of Basterotia, subgenus
Basterotella, from California.

Basterotia (Basterotella) hertleini Durham
Plate 57, Figures 6, 11

Basterotia hertleini Durham, Geol. Soc. Amer., Mem. 43,
Pt. 2, p. 94, pl. 25, figs. 4, 11, August 10, 1950.

242

Basterotia (Basterotella) hertleini Durham, Emerson and
Hertlein, Trans. San Diego Soc. Nat. Hist., Vol. 13,
No. 17, p. 355, figs. 4g-j, 1964. Marquer Formation,
Puerto Ballandra, Carmen Island, Gulf of California,
Pliocene.

Type specimen. — Holotype No. 32274, University
of California (Berkeley), Department of Paleontology,
Type Collection.

Type Locality. — Loc. A 3670 (U. C.), “Upper
Pliocene, Puerto Balandra, Carmen Island. From sands at
left end of outcrop and below base of coral reef (loc.
A3534).”

Range. — Middle and late Pliocene.

Occurrence in San Diego Fm. — L.A.M. 305C.

Original description. — Shell in general resembling
B. peninsulare (Jordan) but more elongate and normally
less inflated; subquadrate, moderately thin, ornamented
by irregular concentric growth lines only; beaks not very
prominent; an angulation running from umbo to posterior
ventral margin; umbos situated about a fourth the length
from the anterior end; a prominent projecting cardinal
tooth in each valve, with adjacent deep ‘“‘socket” anterior
to it in right valve. Length 13.2 mm, height 7.8 mm,
thickness 3.6 mm (one valve). (Durham.)

“This species may be distinguished from B. penin-
sulare (Jordan) by its greater length, greater width between
the angulation and the posterior ventral margin, normally
lesser inflation, and usually less sharp angulation.”
(Durham.}

Remarks. — One right valve of this species, 11 mm
long and 7.3 mm high, is present in the collection from
Loc. 305C (LAM) from near the Mexican boundary. It is
similar to specimens of Basterotia hertleini from the type
locality on Carmen Island in the Gulf of California.

The shell of B. hertleini is very similar to that of
B. ecuadoriana Olsson (684), a Recent species described
from Ecuador. In comparison to the Recent species the
shell of B. hertleini is longer in proportion to the height,
more convex, with a less expanded posterior dorsal area
and a narrower anterior end.

The valve of B. hertleini from the San Diego Forma-
tion differs from B. peninsularis Jordan (685) in the
particulars mentioned by Durham.

Olsson mentioned that the Recent species cited by
Hertlein and Strong (686) under the name of Basterotia
peninsularis from West Mexico, Nicaragua, and the Gala-
pagos Islands, is probably referable to B. ecuadoriana.
We have examined those specimens, and also some others
(787) from the Gulf of California upon which records of
B. peninsularis Jordan were based. The beaks of these
are less elevated and more anteriorly placed than those
on the species described by Jordan. This bears out
Olsson’s suggestion that B. ecuadoriana lives in the Gulf
of California. The range of this species is from San Luis
Gonzaga Bay, east coast of Lower California (and probably
from the head of the Gulf), to Manta, Ecuador, and the
Galapagos Islands.

The only other species of Basterotia described from
the eastern Pacific is B. californica Durham (688) from
strata of Pleistocene age in Lower California. Compared
to the three other species, it is much longer in proportion
to the height. Keen (1971, p. 145) placed both B. cali-
fornica Durham and B. ecuadoriana Olsson in the synony-
my of B. hertleini.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

SUPERFAMILY LUCINACEA FLEMING (689)

Allen (690) discussed the form and adaptation to
habitat of this superfamily, and Boss (Nautilus, vol. 82,
No. 4, pp. 128-130, 1969) recently discussed the relation-
ships of this group of mollusks.

FAMILY LUCINIDAE FLEMING (691)

Shells small or large, subcircular to suborbicular,
generally equivalve, but occasionally somewhat inequivalve
(Miltha), thin or heavy, in the latter case, the interior may
be coarsely pustulose. Hinge when typical has two strong
cardinal teeth and an anterior and posterior lateral tooth
or its socket in each valve, the posterior lateral element
placed distantly at the end of the ligamental scar, in other
forms, the hinge may be degenerate to a greater or lesser
degree, the cardinal teeth and sometimes the laterals be-
come obsolete and often wholly lacking in the adult. The
ligament is external, attached to a deeply immersed scar
lying below the margin of the valve. Adductor scars of
unequal size, the anterior scar typically much larger,
divided, the lower segment narrow and elongated and free
from the pallial line. The pallial line itself entire and
placed near the margin. Ventral margin smooth or
crenulated. Surface sculpture, formed by radial or con-
centric elements or a combination of both. Often with a
scaly periostracum. (Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 206, 1961). Silurian to Recent.

Remarks. — Dall stated that the shell material of
the members of this family is usually porcelaneous or chalky
and the periostracum may be hardly discernible or
may be scaly in character.

The largest member of the family Lucinidae, as
mentioned by Cox (692), is the species described as
Lucina megameris Dall from the late Eocene of Jamaica.
A specimen studied by Cox is 280 mm long and 290 mm
high, the inflation of the valves about 85 mm.

Chaven (693) discussed the classification of this
family in several papers.

GENUS LUCINA BRUGUIERE

Lucina Bruguiere, Encycl. Méth., Tabl. Vers, pls. 284, 285,
286, 1797. [Name and figures only. The illustrations
identified later include Lucina pensylvanica Linnaeus,
L. jamaicensis Lamarck and L. edentula Linnaeus. ]
— Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ.
No. 3, p. 175, 1931. Type as designated by Schumacher.

Type species (designated by Schumacher, Essai

Nouv. Syst. Habit. Vers Test., p. 165, 1817). — Venus

pensylvanica as illustrated by Chemnitz, Syst. Conchyl. —

Cab., Bd. 7, p. 12, pl. 37, fig. 394, 1784. “‘an den Stranden

der westindischen Meere” and ‘von den Ufern der

Danischen westindischen Eylande.”’ [Venus pensylvanica

Linnaeus, Syst. Nat., ed. 10, p. 688, 1758. “Habitat in

America septentrionali.” Ref. to Argenville, Conch., pl.

24, fig. N. Also illustrated by Reeve, Conch. Icon., Vol. 6,

Lucina, species 29, pl. 6, fig. 29, 1850. — Lamy, Jour. de

Conchyl., Vol. 65, No. 2, p. 172, 1920. (Fig. of hinge.) —

M. Smith, East Coast Mar. Shells (Edwards Bros.: Inc.),

p. 46, pl. 15, figs. la, 1b, 1945.]

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Range. — Jurassic to Recent. Recent in from 15
to 7,224 meters (8 to 3950 fathoms).

Description. — Shell orbicular in outline, moderately
inflated, occasionally subglobose, valves closed, lunule
usually well developed, no escutcheon, an oblique
depressed area present along the posterior dorsal margin;
sculpture of concentric lamellae or lines of growth, some-
times also with radial elements; hinge with cardinal teeth
and sometimes with laterals or these may be obsolete;
ligament semi-internal; anterior muscle impression elong-
ated within pallial line, posterior impression oblong;
pallial line entire.

Remarks. — Many of the west American species of
Lucina have appeared, at times, in the literature associated
with the generic name Phacoides. The name Phacoides
was first used by Blainville in a vernacular sense in 1824
(see Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ. 3,
p. 180, 1930). Apparently, the first usage of it as a valid
generic name was by Gray (Proc. Zool. Soc. London for
1847, p. 195) who placed it in the synonymy of Lucina
with the type species ‘‘Ven. jamaicensis.’’ Some authors
retain Phacoides as a subgenus of Lucina (Olsson, 1961,
p. 208), others recommend its abandonment (see Chavan,
1937, p. 141; Keen, 1958, p. 93).

Lucina is widely distributed both geographically
and geologically. It is well represented in the Cenozoic of
western North America. Six species occur in the San Diego
Formation.

At the present time there are numerous species
living in the seas. Lamy (694) published a catalogue of the
Recent species in the collections of the Museum National
dHistorie Naturelle in Paris and the tropical west
American species have been discussed by several authors
(695).

SUBGENUS HERE GABB

Here Gabb, Geol. Surv. Calif., Palaeo., Vol. 2, p. 28,
February, 1866. Lucina (Here) richthofeni Gabb in-
cluded in original list of species. — Stewart, Acad. Nat.
Sci. Philadelphia, Spec. Publ. No. 3, p. 180, 1930.
Type as indicated by Stoliczka. — Chavan, Jour. de

243

Conchyl., Vol. 81, No. 3, p. 202, 1937.
Here richthofeni Gabb.

Type species (designated by Stoliczka, Geol. Surv.
India, Palaeo. Indica, Ser. 6, Cret. Fauna South. India,
Vol. 3, pp. XIX, 251, 1871). — Lucina (Here) richthofeni
Gabb [Geol. Surv. Calif., Palaeo., Vol. 2, p. 29, pl. 8,
figs. 49, 49a, 49b, 1866. ‘“‘Locality: San Fernando Val-
ley, north of Los Angeles; Pliocene.’ — Stewart, 1930,
p. 181, pl. 15, fig. 3; pl. 17, fig. 5, 1930. See also
Chavan, 1937, p. 203, fig. 3].

Range. — Eocene to Recent. Recent from the inter-
tidal zone to 132 meters (72 fathoms).

Original description. — Shell having all of the usual
characters of Lucina, except that the lunule is very
deeply excavated, penetrating the hinge-plate, and almost
perforating it; bounded anteriorly by the anterior lateral
tooth, and posteriorly by the cardinal teeth. (Gabb,
1866.)

Remarks. — This subgenus appears in the Eocene
of Europe, South America, Florida, western North
America, and probably in other regions. It is represented
from Eocene (697) to Recent in the Cenozoic of western
North America. One species occurs in the San Diego
Formation.

The species of this group are characterized by their
rounded subglobular form, very deep lunule, and well
developed concentric sculpture.

Chavan (698) pointed out that Here differs from
Linga de Gregorio (699) in possessing a very deep lunule
which results in the dwarfing of the left anterior cardinal
tooth and complete lack of a right anterior cardinal, and
in possessing more elongated posterior lamellae. The two
groups are quite similar, but for the present at least we
have followed traditional classification in leaving Here as
a subgenus of Lucina.

Illesca Olsson (700) described as a subgenus of Here
differs in that the lunule is “entirely immersed into the
hinge-plate and in both valves seems to have completely
effaced the anterior cardinal.”

In west American waters, Here is represented at the
present time by a single species which ranges from San
Pedro, California, to Mazatlan, Mexico.

Genotype,

Key to Genera and Subgenera of Lucina

A. Hinge with cardinal teeth but
lacking laterals

a. Valves equally convex; strong

concentric lamellae . Lucinoma
aa. Valves unequally convex; con-

centric sculpture of growth

lines only . x Miltha

B. Hinge with both cardinal

and lateral teeth
a. Surface with concentric sculpture only

b. Shell globose; lunule very

deeply impressed. . . . Here

bb. Shell moderately inflated;
lunule not deeply

impressed

c. Lunule nearly equally

divided between the

two valves . . Lucina s. s. (696)
ec. Lunule in greater part

or almost entirely in

the right valve. Epilucina

aa. Surface with radial and
concentric sculpture

d. Radial and concen-
tric sculpture strong,
spiny; margin
denticulate

Radial and concen-
tric sculpture feeble,
unequal, margin
smooth .

Lucinisca
dd.

. Parvilucina

244

Lucina (Here) excavata Carpenter
Plate 46, Figures 1, 2, 3

Lucina excavata Carpenter, Cat. Mazatlan Shells Brit.
Mus., p. 98, November 1855. Mazatlan, Mexico. —
Brann, Illustrations to “Catalogue of the Collection of
Mazatlan Shells” by Philip P. Carpenter (Paleo. Res.
Inst.: Ithaca, New York), pp. 13, 37, pl. 12, fig. 140,
1966. — Keen, Veliger, Vol. 10, No. 4, p. 396, pl. 56,
fig. 23, 1968.

Lucina (Here) richthofeni Gabb, Geol. Surv. Calif., Palaeo.,
Vol. 2, p. 29, pl. 8, figs. 49, 49a, 49b, February, 1866.
“Locality: San Fernando Valley, north of Los Angeles;
Pliocene. Collected by Baron Richthofen.”

Phacoides (Here) richthofeni Gabb, Dall, Proc. U. S. Nat.
Mus., Vol. 23, No. 1237, pp. 810, 827, pl. 40, figs. 7,
9, 1901. ‘Catalina Island to Gulf of California, in 15
to 66 fathoms.”

Phacoides richthofeni Gabb, Keep, West Coast Shells
(The Whitaker & Ray Wiggin Co.: San Francisco), p
69, fig. 45, 1911. “Catalina Island, Long Beach, and
southward.” — J. P. Smith, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 3, pp. 174, 182, 1912. “San Diego -
Purisima.”’

Lucina (Here) excavata Carpenter, Stewart, Acad. Nat.
Sci. Philadelphia, Spec. Publ. No. 3, p. 181, pl. 15, fig.
3; pl. 17, fig. 5, 1930. Earlier records cited, Miocene
to Recent. — Grant and Gale, Mem. San Diego Soc. Nat.
Histes Vole lips 2905 plo 145 figs. 2275) 105 1931:
Also cited from Oligocene to Recent.— _Hertlein and
Strong, Zoologica, Vol. 31, Pt. 3, p. 113, 1946. Gulf
of California, Recent. — Keen, Sea Shells of Tropical
West America (Stanford Univ. Press), p. 94, fig. 188,
1958. Catalina Island, California, to Mazatlan, Mexico,
in 16 to 66 fathoms. — Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 208, pl. 29, figs. 7, 7a, 1961.

Type specimen. — British Museum (Natural History)
(Keen, 1968).

Type locality. — “‘Mazatlan.” [ Mexico. }

Range. — Late Oligocene (Wagner and Schilling)
(701) to Recent. Recent from San Pedro, California, to
Mazatlan, Mexico, in 27 to 121 meters (15 to 66 fathoms).

Occurrence in San Diego Fm. — L.A.M. 107, 305,
305A, 319. S.D. 70.

Original description. — L. t. alba, tenui, complanata;
suborbiculari; striis concentricis exillimis; postice angulata,
umbonibus incurvatis; lunula parva, alte excavata, dent.
card et. lat. haud magnis; impressionibus muscularibus
postica ovali, antica valde elongata; margine integro.
(Carpenter.)

Distinguished by the very small, most deeply cut
lunule, bounded on one side by the cardinal, on the other
by the anterior lateral tooth. A larger lunular portion is
marked out by a line, and the posterior margin is slightly
bi-angulated. Smallest valve 0.03 across. Largest, long.
0.38, lat. 0.41, alt. .12. (Carpenter.)

Remarks. — About 75 valves of this species from the
San Diego Formation, varying in size from 6.4 to 19.3 mm
in length, have been available for study. Most of these are
in the collections of the Los Angeles County Museum from
near the Mexican boundary but a few are from San Diego.
A right valve, 12.4 mm long, in the collections of the San
Diego Society of Natural History, was collected by Samuel

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Harter in Balboa Park.

The globosity of the various valves varies as does
the spacing of the ribbing which may be closely or widely
separated.

Through the courtesy of Dr. Horace G. Richards,
Academy of Natural Sciences of Philadelphia, we have
been able to examine casts of Gabb’s type of Lucina
richthofeni. We have not observed any essential dif-
ferences between these and Recent specimens of L.
excavata from the Gulf of California. We have, albeit
regretfully, placed Gabb’s species from the Pliocene in
the synonymy of the Recent form.

Lamy (702) first stated that Lucina excavata repre-
sented the young form of L. richthofeni Gabb and later,
Stewart, who studied Gabb’s type specimens, placed L.
richthofeni in the synonymy of Carpenter’s species. Both
Lamy and Stewart, pointed out that Lucina ‘“‘excavata?”
cited by d’Orbigny (703) in 1850 was based upon Cytherea
excavata Morton (704) from the Cretaceous of New
Jersey, which species is the type of Cyprimeria Conrad. It
is not referable to the genus Lucina and does not affect
the nomenclature of L. excavata Carpenter.

A subspecies, Lucina (Here) excavata temblorensis
Adegoke (705), of middle Miocene age, was described
from the Coalinga district. It is said to differ from the
typical subspecies in the more prominent beaks, less
circular outline and in other features.

SUBGENUS LUCINISCA DALL

Lucinisca Dall, Proc. U. S. Nat. Mus., Vol. 23, No. 1237,
p. 805, August 22, 1901. “Type, Lucina nassula
Conrad.’ — Chavan, Jour. de Conchyl., Vol. 81, No. 4,
p. 238, 1937. Genotype: L. nassula Conrad.

Type species (by original designation). — Lucina
nassula Conrad [ Proc. Acad. Nat. Sci. Philadelphia, Vol. 3,
p. 24, 1846. “Tampa Bay, Florida.’’ Recent. Illustrated
by Conrad, Amer. Jour. Conch., Vol. 2, Pt. 3, p. 281, pl.
15, fig. 7, 1866 (as Lucina lintea). “‘Inhabits Tampa Bay,
Florida.”” — Perry and Schwengel, Marine Shells of the
western coast of Florida (Paleo. Res. Inst.: Ithaca, New
York), p. 64, pl. 11, fig. 65, 1955.]

Range. — Early Miocene to Recent. Recent in warm
temperate and tropical marine waters, from the intertidal
zone to 183 meters (100 fathoms).

Original description. — Shell lentiform, white, with
well-marked dorsal areas, the sculpture reticulate and
muricate, the right anterior cardinal obsolete. ( Dall.)

Remarks. — The shells of the subgenus Lucinisca are
characterized by their scaly reticulate sculpture, only
slightly asymmetric lunule and by their denticulate inner
margins. Chavan (706) published illustrations of the hinge
of Lucina cribraria Say, a member of this subgenus.

The members of this subgenus are almost entirely
confined to the eastern and western coasts of the Americas
where they are known to occur from early Miocene to
Recent. Three species referred to Lucinisca have been
reported from strata of Miocene age in Japan.

Three species and one subspecies of Lucinisca occur
in west American marine waters between Santa Barbara,
California (Lat. 34°23'N.), and Tumbez, Peru. During
late Pleistocene time one of these ranged north to Tomales

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA
Bay, California (Lat. 38°18 N.).

Key to Species and Subspecies of Lucinisca

A. Concentric ribs closely spaced . nuttalli
B. Concentric ribs widely
spaced .(subspecies) antecedens

Lucina (Lucinisca) nuttalli Conrad
Plate 45, Figures 1-4; Plate 46, Figure 21

L[ucina]. nuttalli Conrad, Jour. Acad. Nat. Sci. Philadel-
PhiasVOloninwbts 2.epe zoo, pl 20) fig. 2) 1837. —
Arnold, Mem. Calif. Acad. Sci., Vol. 3, p. 62, “Pacific
Beach;” p. 133, “Pliocene. — San Diego (Arnold),”
1903. — Arnold, U. S. G. S., Prof. Paper 47, p. 28,
1906. “Pacific Beach, north of San Diego, San Diego
County.” — Hertlein and Grant, Mem. San Diego Soc.
Nat. Hist., Vol. 2, Pt. 1, p. 48, 1944. Dall’s record
(1874) cited.

Lucina nuttallii Dall, Proc. Calif. Acad. Sci., Vol. 5, p.
297, 1874. ‘‘well at San Diego,” “‘Pliocene.”” — Dall,
Proc. U. S. Nat. Mus., Vol. 1, pp. 11, 27, 28, 1878. P.
11, Later Tertiary of San Diego; p. 27, lower bed (A),
San Diego Peninsula; p. 28, San Diego well. — Orcutt,
West. Amer. Sci., Vol. 6, Whole No. 45, p. 70,
Pacific Beach, Tertiary; Whole No. 46, p. 85, Dall’s
record (1874) cited. — Orcutt, cited by Ellis in Ellis
and Lee, U. S. G. S., Water Supply Paper 446, p. 59,
1919. Dall’s record (1874) cited.

Phacoides nuttallii Conrad, Gardner, Jour. Entom. Zool.,
Vol. 9, No. 3, p. 107, pl. 1, fig. 16, 1917. Laguna
Beach, California, Recent. — Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 126, 1924.
“Pliocene at San Diego.” Also other localities. —
Hertlein, Stanford Univ. Bull., Ser. 5, No. 78, p. 84,
1929 (as Phacoides nuttalli). ‘‘San Diego Pliocene.”
— Johnson and Snook, Seashore Animals of the Pacific
Coast (Macmillan Co.: New York), ed. 1935, p. 438,
fig. 414.

Lucina (Myrtea) nuttallii Conrad, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 288, pl. 14, figs.
4a, and 4b (Recent), fig. 18 (Pliocene east of Fernando
Pass, Los Angeles Co., 1931. ‘‘Pliocene of Pacific
Beach, San Diego (Arnold, 1903).”

Lucina (Lucinisca) nuttalli Conrad, Hertlein and Strong,
Zoologica, Vol. 31, Pt. 3, p. 114, 1946. Santa Barbara
California, to Manzanillo and the Tres Marias Islands,
Mexico. Also late Miocene to Recent. — Durham, Geol.
Soc. Amer., Mem. 43, Pt. 2, p. 76, pl. 18, figs. 4, 5,
1950. Upper Pliocene to Recent. — Keen, Sea Shells
of Tropical West America (Stanford Univ. Press:
Stanford, California), p. 96, fig. 191, 1958. Southern
California to the Tres Marias Islands, Mexico.

Lucinisca nuttalli Conrad, Moore, San Diego Soc. Nat.
Hist., Occas. Paper 15, p. 40, pl. 18, fig. d, 1968.
Balboa Park, San Diego, Pliocene.

Type specimen. — Two syntypes, 61.5.20.87,

British Museum (Natural History) (A. M. Keen, Veliger,

245

Vol. 8, No. 3, p. 169, 1966).

Type locality: ‘“‘Inhabits California with the above”
[that is, Lucina californica and L. bella which “Inhabits
muddy marshes near Sta. Diego; common.’’]

Range. — “‘ef.”” Early Miocene (Vaqueros; Temblor).
Late Miocene to Recent. Recent from Santa Barbara,
California, to Punta Penasco and San Felipe in the Gulf
of California and south to Manzanillo, and the Tres
Marias Islands, Mexico; littoral zone to 46 meters (25
fathoms).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 957, 1129, 1178, 1400, 1401, 1402, 1415,
28880, 28885, 28886, 28892. L.A.M. 104, 107, 302,
305, 305A, 318, 319, 323. S.D. 21, 29, 38, 79, 80,
331, 365, 408. U.C.L.A. 294, 302, 312, 331, 1386,
2359.

Original description. — Shell lenticular, slightly com-
pressed; disks cancellated; concentric lines very regular,
lamelliform, prominent; anterior fold small, marginal;
extremity emarginate above; cardinal and lateral teeth
distinct; inner margin minutely crenulated. (Conrad.)

Remarks. — Over 100 valves of this species from
the San Diego Formation have been available for study.
Most of these are in the collections of the Los Angeles
County Museum from near the Mexican boundary and
others from San Diego. One of the largest valves from
Loc. 305 (LAM), is 25.9 mm. long, 25 mm high and the
convexity 7.7 mm.

This species occurs fairly commonly in the San
Diego Formation. The scaly, reticulate sculpture and
denticulate inner margins are features which serve to
separate this species and its subspecies from others of
Lucina which occur in strata of Pliocene age in San
Diego.

Variation in the degree of rounding of the outline
and in the convexity was observed in a series of specimens
of L. nuttalli. Durham (707) mentioned specimens from
beds of late Pliocene age in the Gulf of California region
which were more tumid than usual for this species, but
he acknowledged that occasional Recent specimens are
nearly as convex.

Specimens cited as ‘Phacoides (Lucinisca) cf.
nuttallii’’ (708) have been recorded from beds of early
Miocene age in southern California and the species is well
known in Pliocene and Pleistocene beds in southern
California and in Lower California.

A subspecies, Lucina nuttallii antecedens Arnold,
was described from strata of Pliocene age in Santa
Barbara Co., California. Lucina nuttalli centrifuga Dall
(709), described as a variety from the Gulf of California,
has the concentric lamellae near the beaks widely spaced,
more elevated and fringed with flat spinules. Some
specimens identified as this subspecies from the Gulf of
California which we have observed are very similar to
young specimens of the species later described as Lucina
liana Pilsbry (710).

Fossils from Miocene strata in Japan have been
recorded in the literature by Nomura (711) under the name
of Lucina nuttalli and another species Lucina yokoyamai
Otuka (712), also from Miocene beds, is said to bear some
resemblance to Conrad’s species. We have not seen speci-
mens but evidently L. nuttalli or a very similar form was
present in Japan during Miocene time.

At the present time, Lucina nuttalli has been recorded

246

as ranging north to Santa Barbara, California, but during
late Pleistocene it ranged north to Tomales Bay, California.
We have examined specimens from the Tres Marias Islands,
Mexico, which are typical L. nuttalli.

Lucina (Lucinisca) nuttalli antecedens Arnold
Plate 46, Figures 8, 9, 13, 14

Phacoides nuttalli Conrad, var. antecedens Arnold, Smith-
sonian Misc. Coll. (Quarterly Issue), Vol. 50, Pt. 4, p.
436 (separate p. 18), pl. 55, fig. 6, December 13, 1907.

Lucinisca nuttallii antecedens Arnold, Woodring, in Wood-
ring and Bramlette, U. S. G. S., Prof. Paper 207, pl. 86,
pl. 20, fig. 3; pl. 21, fig. 6, 1950. Diatomaceous strata
of Sisquoc Formation; Foxen Mudstone; Careaga Sand-
stone, late Pliocene.

Type specimen.

National Museum.

Type locality. — “Alcatraz asphalt mine, near
Sisquoc, Santa Barbara County, California; locality No.
4471.” “Fernando formation, lower Pliocene portion.”

Range. — Middle and late Pliocene.

Occurrence in San Diego Fm. — L.A.M. 107, 124,

— No. 165290, United States

305.
Original description. — Shell averaging about 25

millimeters in longitude, very broadly elliptical in outline,
longer than high, ventricose, and equivalve; beaks only
moderately prominent, placed slightly anterior to middle
of shell; base arcuate; anterior margin sloping more rapidly
from beaks than posterior, the latter being nearly straight
for about 6 or 8 millimeters from the beaks; both extrem-
ities quite regularly rounded, the posterior being possibly
slightly more attenuate, sculpture consisting of numerous
close-set subequal rounded radiating ridges and concentric
ribs which are narrower than the radials, and spaced about
twice the distance between two of the latter; the concen-
tric ribs tend to become obsolete toward the periphery in
adult specimens; the general appearance of the surface is
decidedly cancellate. Lunule deep, small, and inconspicu-
ous. Interior and hinge as in P. nuttallii. (Arnold.)

Dimensions. — Longitude, 23 mm; altitude 19 mm;
diameter, 12 mm. (Arnold).

Remarks. — A few valves in the collection from Loc.
305 (LAM), are here referred to Lucina nuttalli antecedens.
The largest one is 18 mm long, 17.3 mm high and 4.5 mm
in convexity. These specimens are rather rounded and
the concentric lamellae on the major portion of the shell
below the umbonal area, are widely spaced. These fossils
are similar to others from the type locality of L. n.
antecedens.

Arnold mentioned the diagnostic characters of this
form as follows: ‘‘This variety is more ventricose, less
angulated posteriorly, and its concentric ribs much wider
spaced than the typical nuttallii.”” Woodring (1950) men-
tioned that the lamellae in the early stages on this sub-
species are closely spaced but are succeeded by more
widely spaced lamellae, which in later stages may be ir-
regularly spaced.

The specimens here illustrated were selected from
among an assemblage of a large number of individuals of
L. nuttalli and it appears to us that the present sub-
species is of doubtful value as a taxonomic unit. However,
the presence of these specimens in the San Diego Forma-
tion, which reveal a tendency to develop the characters

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

mentioned by Arnold has led us to identify them with
L. n. antecedens.

A cast, highly convex, from Reynard Way in San
Diego and perhaps a few valves from Loc. 124 (LAM)
are doubtfully referred to the form named by Arnold.

Woodring, 1950, recognized only L. n. antecedens
in Pliocene strata at its type locality and in adjacent areas
in Santa Barbara Co.

SUBGENUS LUCINOMA DALL

Lucinoma Dall, Proc. U. S. Nat. Mus., Vol. 23, No. 1237,
p. 806, August 22, 1901. “Type, Lucina filosa
Stimpson.” — Dall, Trans. Wagner Free Inst. Sci., Vol.
3, Pt. 6, p. 1362, October, 1903. Type, Lucina filosa
Stimpson. — Chavan, Jour. de Conchyl., Vol. 82, No. 1,
p. 80, 1938. Genotype, Lucina filosa Stimpson.

Type species (by original designation). — Lucina
filosa Stimpson. [Lucina filosa Stimpson, Shells of New
England, p. 17, 1851. Illustrated by Stearns, Proc. U. S.
Nat. Mus., Vol. 13, No. 813, p. 220 (in text), pl. 17, figs.
5, 6, 1890. — Dall, Proc. U. S. Nat. Mus., Vol. 23, No.
1237, pp. 809, 824, pl. 40, fig. 11, 1901 (as Phacoides
(Lucinoma) filosus). See also illustrations of hinge of L.
borealis Linnaeus by Lamy, Jour. de Conchyl., Vol. 65,
No. 2, p. 171, 1920.]

Range. — Late Oligocene to Recent, widespread.
Recent species in western North America live in marine
waters between Afognak Island, Alaska, and the Gulf of
California, at depths of 15 to 1838 meters (8 to 1005
fathoms).

Original description. — Shell usually large, lentiform,
white, with a conspicuous periostracum, concentrically
lamellose or striated; the cardinal teeth developed, the
inner pair usually bifid; the laterals obsolete or absent,
the inner margins entire. (Dall.)

Remarks. — This group of lucinids with well devel-
oped concentric lamellar sculpture and weak lateral teeth
is widely distributed geographically and geologically. Five
and perhaps six species referable to Lucinoma have been
described from late Oligocene to Recent, in western North
America, and one of these, a Recent species, occurs in the
San Diego Formation. Three Recent species live in west
American waters.

Lucinoma also is represented in the late Cenozoic
of eastern North America, South America, Europe, Japan,
and New Zealand. It is well represented in the north
Pacific. Hirayama (713) discussed several species of
Miocene age occurring in Japan. Far to the southwest,
Powell described Myrtea (Lucinoma) taylori (714) from
beds of Awamoan, early Miocene age, in New Zealand.
Dell (715) described a Recent species, Lucinoma marwicki,
from a depth of 361 meters in the same region, and more
recently Lemche added Lucinoma galatheae (716) to the
known molluscan fauna of New Zealand.

In general, as pointed out by Dall, the members of
Lucinoma prefer cool water. However, species also are
known to occur in tropical waters. Lucina (Lucinoma)
chiripanica Olsson (717) was described from beds of
Pliocene age in Panama. Melville and Standen (718)
recorded a tropical variety of Lucina borealis in the
Persian Gulf and Thiele and Jaeckel (719) cited the same
species from the East Indies, and there are other examples.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Alucinoma Habe (720) differs from Lucinoma in
lacking cardinal teeth.

Lucina (Lucinoma) annulata Reeve
Plate 46, Figures 12, 19

Lucina annulata Reeve, Conch. Icon., Vol. 6, Lucina, sp.
17, pl. 4, fig. 17, May, 1850.

Lucina borealis Linnaeus, Dall, Proc. Calif. Acad. Sci.,
Vol. 5, p. 297, 1874. “Well at San Diego,” “Pliocene.”
— Cooper, Calif. State Min. Bur. Seventh Ann. Rept.
State Mineral., p. 246, 1888. “San Diego Well.” —
Orcutt, West Amer. Sci., Vol. 6, Whole No. 46, p. 85,
1889. Dall’s record (1874) cited. — Hertlein and Grant,
Mem. San Diego Soc. Nat. Hist., Vol. 2, Pt. 1, p. 48,
1944. Dall’s record (1874) cited and referred to
Lucina (Lucinoma) annulata.

Not Lucina borealis Linnaeus,
Europaeo.”

Lucina acutilineata Conrad, Dall, Proc. U. S. Nat. Mus.,
Vol. 1, pp. 11, 28, 1878. P. 11, Later Tertiary of San
Diego; p. 28, San Diego well. — Orcutt, West Amer.
Sci., Vol. 6, Whole No. 46, p. 86, 1889. Dall’s record
(1878) cited. — Arnold, Mem. Calif. Acad. Sci., Vol. 3,
p. 132, 1903. ‘San Diego well (Cooper).” — Orcutt,
quoted by Ellis in Ellis and Lee, U. S. G. S., Water
Supply Paper 446, p. 59, 1919. Dall’s record (1878)
cited.

Not Lucina acutilineata Conrad, 1848.

Phacoides acutilineatus Conrad, Reagan, Trans. Kansas
Acad. Sci., Vol. 22, p. 179, 1909. ‘San Diego well
(Cooper).”

Phacoides annulatus Reeve, J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 3, pp. 174, 182, 1912. “San Diego-
Purisima,” Pliocene. — Packard, Univ. Calif. Publ. Zool.,
Vol. 14, No. 2, p. 263, pl. 19, figs. 5a, 5b, 1918.
“Range. — Alaska to Coronado Island, California
(Dall).”

Phacoides (Lucinoma) annulatus Reeve, I. S. Oldroyd,
Publ. Puget Sound Biol. Sta., Vol. 4, p. 38, pl. 37,
figs. 5a, 5b, 1924. “Port Althorp, Alaska, to Coronado
Islands, Lower California.” Recent. — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. ieps
126, pl. 33, figs. 5a, 5b, 1924. Same range as in pre-
ceding reference. Also, late Miocene, Pliocene, Pleisto-
cene. — Abbott, American Seashells (D. Van Nostrand
Co., Inc.: New York), p. 389, fig. 28f (p. 83), 1954.
Alaska to southern California, in 8 to 75 fathoms.

Lucina (Myrtea) acutilineata Conrad, Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 287, pl. 14,
figs. 22a, 22b (Pleistocene of San Pedro), 1931. “San
Diego well, middle Pliocene, San Diego (Cooper).”

Not Lucina acutilineata Conrad, 1849.

Lucinoma annulata Reeve, Keen, Sea Shells of Tropical
West America (Stanford Univ. Press: Stanford, Cali-
fornia), p. 97, fig. 197, 1958. Gulf of California. —
Moore, San Diego Soc. Nat. Hist., Occas. Paper 15,
p. 40, pl. 18, figs. a, b, c, 1968. Balboa Park, San
Diego, Pliocene.

Type specimen. — Syntypes Nos. 1963 121/1-2,

British Museum (Natural History).

Type locality. — “Hab. California?”
Range. — Late Miocene to Recent. Recent from

Afognak Island (Kodiak group), and Macleod Bay,

1767. ‘In Oceano

247

Montague Island, Alaska, to Santa Inez Bay, Lower Cali-
fornia; in 18 to 757 meters (10 to 414 fathoms) (Wood-
ring, U. S. G. S., Prof. Paper 190, p. 53, 1938). Japan.

SUBGENUS EPILUCINA DALL

Epilucina Dall, Proc. U. S. Nat. Mus., Vol. 23, No. 1237,
p. 806, August 22, 1901. “Type, Lucina californica
Conrad.” — Chavan, Jour. de Conchyl., Vol. 81, No. 4,
pp. 249, 272, 1937. Genotype, Lucina californica
Conrad.

Type species (by original designation). — Lucina
californica Conrad, Jour. Acad. Nat. Sci. Philadelphia,
Vol. 7, p. 255, pl. 20, fig. 1, 1837. Near San Diego, Cali-
fornia. Hinge illustrated by Chavan, 1937, p. 274, fig. 10.

Range. — Bathonian, late Jurassic, to Recent
(Chavan). Recent from the intertidal zone to 143 meters
(78 fathoms).

Original description. — Shell veneriform, convex, all
the hinge teeth developed, inner margins entire; otherwise
like Callucina. (Dall.)

Remarks. — The shell of Epilucina, as pointed out
by Chavan, differs in several important details from that
of Callucina Dall (729) which has as its type Lucina
radians Conrad. Among those differences are, the position
of the lunule which is situated entirely in the right valve
instead of partly in the left one, smooth inner margins
and strongly projecting laterals (which on Callucina are
very slightly developed).

We have not studied species upon which Chavan
based the early range of this subgenus. Claibornites
Stewart, 1930, was relegated to the synonymy of Epilucina
by Chavan.

Lucina (Epilucina) californica Conrad
Plate 46, Figures 11, 16

L[ucina]. californica Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 255, pl. 20, fig. 1, 1837.

Phacoides californicus Conrad, Keep, West Coast Shells
(The Whitaker & Ray-Wiggin Co.: San Francisco,
Calif.), p. 67, fig. 43, 1911. ‘“‘coast of central Cali-
fornia”. Also ed. by Baily, 1935, p. 82, fice 55s
Johnson and Snook, Seashore Animals Pacific Coast
(Macmillan Co.: New York), p. 438, fig. 415, 1935.

Lucina (Myrtea) californica Conrad, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 285, pl. 14, figs.
15a, 15b, 21a, 1931. Pliocene to Recent.

Codakia californica Conrad, Abbott, American Seashells
(D. Van Nostrand Co., Inc.: New York, London;
Toronto), p. 390, pl. 31, fig. c, 1954. “Crescent City,
California, to Lower California.”

Type specimen. — Location unknown to the pre-
sent authors.

Type locality. — “‘Inhabits the coast of California
with the above, but rare.” [Preceding species is Lucina
bella from “Inhabits muddy marshes near Sta. Diego;
common.”’ |

Range. —?Late Miocene; middle Pliocene to Recent.
Recent from Crescent City, California, to San Ignacio
Lagoon, Lower California, from the intertidal zone to
143 meters (0 to 78 fathoms). Reported from Alkai
Point, Seattle, Washington, by Eyerdam (730).

248

Occurrence in San Diego Fm. — L.A.M. 305, 305A,
318. S.D.5. U.C.L.A. 294, 295.

Original description. — Shell lenticular, with coarse
concentric striae; posterior extremity direct; lunule small,
elliptical, impressed, transversely striated, prominent in
the right valve, and fitting into a corresponding depres-
sion in the left; cardinal and lateral teeth prominent.
(Conrad.)

The lunule in the shell is remarkable for forming a
distinct tooth, and the shell is destitute of a fold.
(Conrad.)

Remarks. — Several valves of this species are in the
collections from near the Mexican boundary. Small valves
up to 9 mm in length are very elongated. The largest
valve from Loc. 305 (LAM) is 19.5 mm long. Two small
right valves from the south slope of Mount Soledad, are in
the collection of the San Diego Society of Natural History.
The larger one is 13.6 mm long, 13.7 mm high, convexity,
4.2 mm. A large Recent specimen collected at San Diego
by Henry Hemphill is 35.9 mm long, 34 mm high, the
convexity (both valves together), 19 mm. The hinge of
this species has been illustrated by Chavan (731).

The shell of this species is easily separable from that
of other species of Lucina occurring in Pliocene beds in
California by the complete lack of any depressed area
either posteriorly or anteriorly, concentric sculpture only,
and in the character of the lunule which lies entirely in
the right valve.

The species described as Lucina (Myrtea) nipponica
Nomura and Hatai (732) from beds of middle Miocene age
in Japan was compared with L. californica. The Japanese
species was said to differ in the smaller size, finer sculpture,
and in the somewhat different outline.

Lucina californica is known to occur in beds of late
Pliocene age on Cedros Island, Lower California, from
Fourth and Broadway streets in Los Angeles, and the pre-
sent record adds its occurrence in the San Diego Forma-
tion. Gale (733) recorded it with question in the lower
zone in the Frutivale district in the San Joaquin Valley in
strata of late Miocene age. However, Grant and Gale in
their later work (1931) made no mention of this record.
It occurs commonly in Pleistocene deposits in southern
California and northern Lower California as well as Recent.

SUBGENUS PARVILUCINA DALL

Parvilucina Dall, Proc. U. S. Nat. Mus., Vol. 23, No. 1237,
p. 906, August 22, 1901. “‘Type, Lucina tenuisculpta
Carpenter.’’ — Dall, Trans. Wagner Free Inst. Sci., Vol.
3, Pt. 6, p. 1362, 1903. Type, Lucina tenuisculpta
Carpenter. — Woodring, Carnegie Inst. Washington,
Publ. 366, p. 125, 1925. Type as designated by Dall. —
Chavan, Jour. de Conchyl., Vol. 81, No. 3, p. 208,
1937. Genotype, Lucina tenuisculpta Carpenter.

Type species (by original designation). — Lucina
tenuisculpta Carpenter [Rept. Brit. Assoc. Adv. Sci., for

1863, p. 642, August, 1864. Reprint in Smithsonian

Mise. Coll., No. 252, p. 128, 1872. Cited from ‘“‘Puget’s

Sound and the neighbourhood” and the region between

San Diego and San Pedro, also the Santa Barbara Islands.

“4 fm. living, Cp.”” The island variety, 120 fms. Illustrated

by Dall, 1901, p. 828, pl. 40, fig. 5, 1901. — Chavan,

1937, p. 209, fig. 4. — K. V. W. Palmer, Geol. Soc. Amer.

Mem. 76, p. 86, pl. 8, figs. 8-12, 1958. (Holotype).]

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Range. — Late Cretaceous (Senonian) (Chavan,
Treatise on Invert. Paleo., Pt. N, Moll. 6, Bivalvia, Vol. 2,
p. N498, 1969); mid-Eocene to Recent, North America
(Woodring). Recent from the intertidal zone to 525
meters (287 fathoms).

Original description. — Shell small, plump, often
inequilateral; sculpture more or less reticulate but not
muricate, teeth small, but all usually present. For
Parvilucina s. s.: Dorsal areas obscure or obsolete, sculp-
ture feeble. (Dall.)

Remarks. ~— This subgenus is represented in the late
Cenozoic of western North America by two species and a
subspecies, the latter occurs in the San Diego Formation.

A subgenus Callucinella Chavan (734) was described
as differing from Parvilucina in the larger size, irregular
concentric sculpture, very fine crenulations on the margin,
and longer lunule. The hinge also differs from Parvilucina,
among other features, in the presence of a lateral lamella
and in the elongated cardinal teeth, especially the posterior
ones.

Lucina (Parvilucina) tenuisculpta intensa Dall
Plate 46, Figures 6, 7,17, 22

Lucina tenuisculpta Carpenter, Dall, Proc. Calif. Acad.
Sci., Vol. 5, p. 297, 1874. Well at San Diego, Cali-
fornia, Pliocene. — Dall, Proc. U. S. Nat. Mus., Vol. 1,
p. 28, 1878. From “‘well-digging in stratum B2”, San
Diego, Pliocene. — Orcutt, cited by Ellis in Ellis and
Lee, U. S. G. S., Water Supply Paper 446, p. 59,
1919. Dall’s record (1874) cited. — Hertlein and Grant,
Mem. San Diego Soc. Nat. Hist., Vol. 2, p. 48, 1944.
Dall’s record (1874) cited.

Not Lucina tenuisculpta Carpenter.

Phacoides (Parvilucina) intensus Dall, Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 6, p. 1385, pl. 50, fig. 8, October,
1903. — Schuchert, Dall, et al., U. S. Nat. Mus., Bull.
No. 53, Pt. 1, p. 497, 1905. Original locality cited. —
Keen and Bentson, Geol. Soc. Amer., Spec. Papers No.
56, p. 98, 1944. Original locality record cited.

Phacoides intensus Dall, Arnold, Smithsonian Mise. Coll.
(Quart. issue), Vol. 50, Pt. 4, pp. 423, 445, pl. 56, figs.
9a, 9b, 1907. One mile north of Schumann; “Waldorf
asphalt mine”. “Found in lower Pliocene as far south
as San Diego.” — Arnold, U. S. G. S., Bull, 322, pp. 59,
148, pl. 23, figs. 9a, 9b, 1907. [Same locality informa-
tion as in preceding reference.]| — Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 288, 1931.
[In synon. of Lucina (Myrtea) tenuisculpta Carpenter].
Dall’s record (1874) cited. — Woodring, in Woodring
and Bramlette, U. S. G. S., Prof. Paper 222, p. 86,
1950. ‘Pliocene strata encountered in a well at San
Diego.”

Type specimen. — No. 135041, United States Nat-
tional Museum.

Type locality. — ‘‘Pliocene of San Diego, California,
from a depth of one hundred and sixty feet below the
surface in the city park well; Hemphill.”

Range. — Middle and late Pliocene in southern
California.

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 305, 305A, 318, 319. U.C.L.A. 294.

Original description. — Shell small, resembling P.
tenuisculptus Cpr., but with the concentric sculpture

;

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

much sharper though very fine, the radials feeble, the
lunule large, lanceolate, and impressed, the beaks small
and prominent, the hinge very delicate, the posterior
dorsal area with a wide, shallow sulcus, and the inner
margins rather coarsely crenulate. Alt. 4.5 mm, long. 5.0
mm, diam. 3.0 mm. (Dall, 1903.)

Remarks. — Five valves from the original lot col-
lected by Henry Hemphill from which the type of this
species was described are in the type collection in the
Department of Geology of the California Academy of
Sciences. The largest, a left valve, is approximately 8 mm
long, 6.4 mm high, convexity, 3.4 mm. The other valves
in the collection are much smaller.

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 957, 1135, 1178, 1181, 1182, 1183, 1186,
1399, 1400, 1401, 1402, 1413, 1415, 1418, 1419, 12053.
L.A.M. 104, 107, 122, 305, 305A, 319, A-1323. S.D.
34, 38, 79, 150, 331, 365, 2930. U.C.L.A. 294, 295,

2359. ae s
Original description. — Shell orbicular, rather

flattened, inequilateral, concentrically laminately ridged,
ridges sharp, erect, interstices concentrically striated,
lunule lanceolately ovate, rather deeply excavated; semi-
transparent white. (Reeve.)

Remarks. — This species is encountered rather com-
monly in the San Diego Formation. It is easily recognized
by its rounded form, nearly straight posterior dorsal mar-
gin and well developed and well spaced (about 2.5 to
3 mm apart) concentric lamellar sculpture.

We have observed about 30 valves and a number of
casts of this species from the San Diego Formation. The
largest valve, from Loc. 305 (LAM), is 61.6 mm long
and 57 mm high. Young specimens have a weak anterior
lateral tooth.

Some writers have considered this species to be
identical with Lucina acutilineata Conrad (721) which was
originally described from beds of Miocene age at Astoria,
Oregon. The length was given as 1 1/2 inches, the height
slightly less than the length and the “‘thickness 45/100
L.” Stewart (722) examined Conrad’s type specimen and
stated that it has a shorter posterior dorsal margin than
that of Recent L. annulata. Woodring (723) also recog-
nized this difference between the two, mentioned that
Miocene specimens are usually smaller than Recent shells
and designated a specimen as lectotype of L. acutilineata.
A Recent specimen of L. annulata from Loc. 34051
(CAS), dredged in 165 meters (90 fathoms) off Gaviota,
California, is 73 mm long and 66 mm high.

Dall’s (724) diagnosis of “‘Phacoides acutilineatus”
was based upon a somewhat worn specimen of Pliocene
age from Coos Bay, Oregon, and may not be referable to
Conrad’s species.

The generally longer posterior dorsal margin, much
greater size, and hinge characters of the Pliocene and Recent
shells, justify assigning them to Lucina annulata with the
status of a distinct species.

Lucina annulata desilirata Dall (725) was described
as differing from the typical form in the more steeply
sloping posterior dorsal margin and in that the primary
concentric lamellae are more irregularly spaced.

The species described as Phacoides columbianum
Clark and Arnold (726), closely resembles L. acutilineata
but it was said to differ in lacking a posterior depressed
area and in possessing an anterior lateral tooth on the

249

hinge of the left valve.

Lucina hannibali Clark (727), which occurs com-
monly in the Blakely Formation of Washington and in
beds of equivalent age in Alaska and Japan, is characterized
by the attenuated anterior portion of the shell.

Two Recent species occurring in west American
waters, Lucina aequizonata Stearns and L. heroicus Dall,
have more steeply sloping dorsal margins and thus differ
in outline from L. annulata.

Lucina annulata has been recorded (728) occurring
in Japanese waters from 31° to 41°North latitude and
several similar species occur as fossils in strata of late
Tertiary age in the same region.

Over a hundred and fifty valves are in the collections
of the Los Angeles County Museum from near the Mexican
boundary. The largest one, from Loc. 319 (LAM), is
8 mm long.

These valves differ from Recent specimens of
Lucina (Parvilucina) tenuisculpta Carpenter (735) chiefly
in their smaller size, stronger concentric sculpture and in
the larger lunule. Large specimens of L. tenuisculpta
from Port Orchard, Puget Sound, are 11 mm long and
10 mm high; and Woodring mentioned specimens of this
species which are 14 mm long.

Woodring believed that the apparent stronger con-
centric sculpture of Lucina intensa mentioned by Dall in
comparison with Carpenter’s species may be due to
erosion of the early portions of Recent shells of L.
tenuisculpta. The consistently smaller size of the Pliocene
fossils together with the larger lunule, and at least in the
type series, stronger concentric sculpture leads us, at least
for the present, to assign subspecific status to the form
described by Dall.

Lucina (Parvilucina) approximata Dall (736) des-
cribed from the Gulf of California bears some similarity
to L. tenuisculpta intensa, but it has much stronger radial
sculpture.

GENUS MILTHA H. AND A. ADAMS

Miltha H. and A. Adams, Gen Rec. Moll., Vol. 2, p. 468,
April 1857. Sole species, Lucina (Miltha) childreni
Gray. — Olsson and Harbison, Acad. Nat. Sci. Philadel-
phia, Monogr. No. 8, p. 88, November, 1953. Type by
monotypy. — Vokes, Tulane Studies Geol. Paleo., Vol.
7, No. 3, p. 95, December 29, 1969. Type by mono-
typy.

Type species (by monotypy). — Lucina (Miltha)
childreni Gray [=Lucina childrinae Gray, Zool. Jour., Vol.
1, No. 2, p. 221, footnote, June, 1824. No locality cited.
(In errata, “for childrinae, read childreni.”) — Gray, Ann.
Philos., New Ser., Vol. 9, p. 136, February, 1825 (as
Lucina childrenae). ‘‘Brazile’’. — Reeve, Conch. Icon.,
Vol. 6, Lucina, sp. 12, pl. 3, fig. 12, 1850 (as Lucina
childreni). ‘‘Brazile.”” — Wilkins, Bull. Brit. Mus, (Nat.
Hist.), Historical Ser., Vol. 1, No. 4, p. 159, pl. 23, fig. 6,
March, 1957. ‘‘From Brazil.’ “Lectotype.” — Vokes,
1969, p. 116, pl. 1, fig. 1; pl. 2, figs. 1a, b; pl. 4, figs.
1-4 (as Miltha (Miltha) childrenae).

Range. — Eocene to Recent. East and west coasts
of the Americas (Miltha, s. s.). Recent from 33 to 101
meters (18 to 55 fathoms). Also reported from the late

250

Tertiary of Australia and New Zealand.

Description. — Shell subovate to subelliptical with
a fine to coarse concentric sculpture. Lunule asym-
metrical, larger in the left valve and generally trans-
gressing across the valve margin into the interior. Liga-
ment large, external, immersed. Anterior adductor scar
very long and narrow, near or quite widely separated from
the pallial line which is parallels. (Olsson and Harbison.)

The hinge of Miltha has two teeth in each valve but
laterals are lacking.

Remarks. — The large suborbicular, depressed in-
equivalve lucinids referred to Miltha s. s. appear to be
limited to the American region during both past and pre-
sent time.

Several groups of species formerly cited under
Miltha have been placed under separate subgenera.
Pseudomiltha Fischer (737), an Eocene-Oligocene group
has a virtually edentulous hinge. Eomiltha Cossman (738),
Eocene to Recent, differs from Miltha in that it is more
produced anteriorly, the pallial line is close to the margin,
the anterior adductor impression is narrower, longer, and
farther from the pallial line and the hinge lacks anterior
lateral-like ridges. Plastomiltha Stewart (739) is said to
differ from Miltha in the deeper lunule, smaller cardinal
teeth, and in that the anterior adductor impression is
narrower. Olsson and Harbison (1953, pp. 83-84) con-
sider that subgenus to be confined to beds of Eocene
age and they consider it to be more closely related to
“Phacoides” than to Miltha. Armimiltha Olsson and
Harbison (740) based upon Lucina disciformis Heilprin, a
Pliocene species, is said to differ from Miltha in the much
stronger sculpture and from ‘Plastomiltha by the larger
lunule which with growth partially effaces the cardinal
teeth, the larger of which is double.

Species of Miltha s. s. inhabit tropical or subtropical
waters at the present time and apparently this also was
true of the fossil forms of this group. Species referred
to this and related subgenera (or genera) lived in widely
separated regions of the world during later Tertiary time,
Species have been described from California and Lower
California, Peru, Argentina, Florida, and New Zealand.
The distribution of Miltha in the later Tertiary of south-
eastern Australia was discussed by Wilkins (741). A
recent paper by Vokes (742) contains a comprehensive
account of the genus Miltha and of the Neogene species in
Florida.

During early Miocene time in western North America
Miltha s. s. ranged as far north as Santa Cruz Co., Cali-
fornia. During Pliocene time it occurred as far north as
San Benito Co., whereas during succeeding Pleistocene
time it is known with certainty to occur only as far north
as Magdalena Bay on the west coast of Lower California.

Khomenko (743) recorded a species assigned to this
genus from beds of the Matchgar section, middle Miocene,
in the Schmidt Peninsula, Kamtschatka, but we have not
seen specimens from that region.

Recent species of Miltha s. s. now live only in
waters of Brazil and the Gulf of California.

SUBGENUS MILTHA S. S.

Miltha (Miltha) xantusi Dall
Plate 45, Figures 14-17

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Phacoides (Miltha) childreni Gray, Dall, Proc. U. S. Nat.
Mus., Vol. 23, No. 1237, p. 812, 1901. “Gulf of
California, Cape St. Lucas, Mazatlan.”

Not Lucina childrinae Gray, 1824. (Lucina childrenae
Gray, 1824).

Phacoides (Miltha) xantusi Dall, Nautilus, Vol. 18, No. 10,
p. 111, February 1905. “Cape St. Lucas.”

Phacoides sanctaecrucis Arnold, J. P. Smith, Proce. Calif.
Acad. Sci., Ser. 4, Vol. 3, pp. 167, 174, 1912. “San
Diego-Purisima.” Pliocene.

Not Phacoides (Miltha) sanctaecrucis Arnold, 1909 (1910).
Phacoides xantusi Dall, Hertlein, Stanford Univ. Bull., Ser.
5, No. 78, pp. 84, 85, 1929. ‘“‘San Diego Pliocene.”
Lucina (Miltha) xantusi Dall, Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 291, pl. 14, figs. 20a,
20b (middle Pliocene of Holser Canyon, Los Angeles
Co.), 1931. [Not all the synonymy.] — Hertlein and
Strong, Zoologica, Vol. 31, Pt. 3, p. 115, pl. 1, fig. 13,
1946. Cape San Lucas, Lower California, Arena Bank,

Gulf of California, Recent.

Miltha xantusi Dall, Durham, Geol. Soc. Amer., Mem. 43,
Pt. 2, p. 77, pl. 19, figs. 3, 8, 1950. Coronado Island,
Gulf of California, Pleistocene. — Olsson, Mollusks of
the Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), p. 215, pl. 30, fig. 4, 1961. Lower Cali-
fornia. — Moore, San Diego Soc. Nat. Hist., Occas.
Paper 15, p. 40, pl. 18, figs. e, f, 1968. Balboa Park,
San Diego, Pliocene.

Miltha (Miltha) xantusi Dall, Keen, Sea Shells of Tropical
West America (Stanford Univ. Press: Stanford, Cali-
fornia), p. 98, fig. 198, 1958. Taken mostly off Cape
San Lucas, Lower California, in 30 or more fathoms.

Type specimen. — No. 5383, United States National
Museum.

Type locality.—‘‘Cape St. Lucas,” Lower California,
Mexico.

Range. — Late Miocene (Castaic Formation) (744),
to Recent. Recent, Cabo Haro, west of Guyamas Bay,
Sonora, to Mazatlan, Sinaloa, and La Paz to Cape San
Lucas, Lower California, Mexico, in 33 to 101 meters (18
to 55 fathoms).

Occurrence in San Diego Fm. — C.A.S. 1401, 1402.
L.A.M. 302, 305, 305A, P.87. S.D. 29, 61, 80, 5251.
U.C.L.A. 2359.

Original description. — “The P. xantusi seems to be
a smaller species when adult, more rounded, more equl-
valved and with a shorter ligament. It has a more or less
bifurcate and vermiculate radial sculpture, that of P.
childreni being finer, more regular and more distinctly
divided into fine continuous radial grooves and a micro-
scopic minor sculpture between them.

“As in many other Lucinacea, directly under the
beaks there is a small impressed area. In P. xantusi this
in the right valve projects so as to fill an excavation in the
other valve and is so much impressed as to make the beak
appear sharper and more produced and to distinctly
arcuate the two cardinal teeth. .. . . In the California
species the lunule is very small and bent vertically down-
ward so that in the closed valves it is excavated and not
projecting and has a length of about 6 mm. It is almost
wholly confined to the right valve.” Measurements:
height, 71 mm, width 65 mm. (Dall, 1905.)

Remarks. — A large series of specimens referable to
the present species is represented in the collections from

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Balboa Park and Mount Soledad. These agree in all
observable details with a Recent specimen from the Gulf
of California illustrated by Hertlein and Strong as well as
with fossil specimens from Pleistocene beds in the Gulf of
California region such as illustrated by Durham. One of
the largest specimens is 72 mm high, 67 mm long, the
convexity (both valves together), 26.4 mm. A more
rounded specimen is 68.5 mm high, 69.6 mm long, con-
vexity, 22.4 mm (both valves together). A specimen from
Loc. P. 87 (LAM), Reynard Way, San Diego, is 63 mm
long, 63 mm high, convexity, 21.5 mm.

There is considerable variation in shape and in the
degree of convexity. Young shells are generally more
rounded in outline. Many shells, especially large ones, are
elongated from beak to base. The left valve is usually
flatter than the right, but in some specimens the valves
are of nearly equal convexity, and occasionally the left
valve may be the more convex of the two. The lunule as
described by Dall is mostly in the right valve, is impressed,
and is about 6 mm in length. On some specimens a sub-
median slight depression or faint broad groove extends
from the umbo to the base, but on others it is lacking.
The right valve has two cardinal teeth, slightly grooved in
large specimens, the left valve with a shorter anterior
cardinal and a posterior cardinal (sometimes faintly
grooved) and a long posterior nymph. The interior of the
valves sometimes bears fine pits, in others the interior
may be thickened in part with shell material. The margins
are smooth. Externally the surface is sculptured with con-
centric lines of growth, occasionally with deeper grooves
and often with faint radial lines visible, especially on the
medial portion of the valves. Recent shells are pure white.

This species was cited in the earlier literature under
the name of Lucina or Miltha childreni Gray, the type of
the genus Miltha, which occurs in Brazil. Dall, in 1901,
cited it from the Gulf of California under the name of
Phacoides (Miltha) childreni Gray. In 1903 he cited it as
occurring in beds of Pliocene age at San Juan in the Gulf
of California. Two years later he described the Recent
species in the Gulf of California as Phacoides (Miltha)
xantusi, and the fossil form from San Juan was described
as Phacoides joannis (745). According to Dall, this
Pliocene form “‘resembles the Recent P. xantusi in having
the folded lunule, only, in this case, the margin is more
deeply infolded and the shell heavier, more elongate-oval,
and about one-fourth smaller. It measures 55 mm in
height by 51 mm in width; P. xantusi, 71 x 65 mm, and
P. childreni, 86 x 77 mm.”

We have examined a cast of the type of Phacoides
jJoannis, a left valve. The impressed lunular area on this
specimen may be slightly deeper than that on M. xantusi,
and the interior of the shell appears to be nearly filled
with shell material. However, in all other particulars it
agrees with specimens of M. xantusi of the same size. We
are inclined to consider M. joannis to be referable to the
Recent species, M. xantusi.

Phacoides (Miltha) sanctaecrucis Arnold (746) was
described from strata of early Miocene age in the “reef
bed” in the Devil’s Den district, Kern Co., California.
Arnold mentioned that his species” “‘is characterized by its
large size, circular outline, slight angulation dorsally,
compressed disk, prominent lunule and dorsal areas, and
finely concentrically striate but otherwise unsculptured
surface.”’ He stated that it is closely allied to the Recent

251

species in the Gulf of California “but may be distinguished
by its shorter lunule and relatively greater breadth.”

We have examined a cast of the type specimen of
Arnold’s species. The valves are thick, nearly equal in
convexity and decidedly circular in outline. There is
variation in the series of specimens of this species from
beds of Miocene age, but in general the valves appear to be
thicker, more nearly equal in convexity and more circular
in outline in comparison with Recent and fossil speci-
mens of Miltha xantusi. We are inclined, at least for the
present, therefore, to retain M. sanctaecrucis as a distinct
species.

Stoliczka (747) mentioned that the Cretaceous spe-
cies described by Pictet and Campiche as Lucina sanctae-
crucis (748) ‘may belong to Mysia rather than to Lucina.”
Fortunately, the original assignment of Arnold’s species
to the genus Phacoides avoids invalidation as a homonym
of the European species.

The resemblance of Miltha pacifica Olsson (749),
described from strata of Miocene age in Peru, to M.
sanctaecrucis Arnold was pointed out by Olsson. Miltha
s. s. is also represented in Argentina by M. inheringiana
Doello-Jurado (750) described from beds of the En-
trerrienne Formation of probable Miocene age.

Miltha neozealanica Marshall and Murdoch (751),
described from late Tertiary beds in New Zealand, was
said to resemble closely M. sanctaecrucis Arnold. This
New Zealand species was made the type of Milthoidea
Marwick (752), but according to Chavan, and Ludbrook
(753), Marwick’s genus can be placed in the synonymy of
Miltha s. s.

Probably most of the records of Miltha sanctae-
crucis from beds of Pliocene age in southern California are
referable to M. xantusi. However, some specimens (754)
from Pliocene beds in Imperial Co. do resemble Arnold’s
species.

Miltha xantusi is known to occur in Pliocene and
Pleistocene beds in the Gulf of California region and in
Pleistocene beds at Magdalena Bay, Lower California,
where it was recorded by E. K. Jordan (755). This species,
under the name of Miltha childreni, was reported by
J. P. Smith (756) as occurring in strata of late Pleistocene
age at San Pedro, California, but later workers have not
mentioned it from those beds.

FAMILY DIPLODONTIDAE DALL (757)

Shells of this family are generally small (length up
to about 40 mm), suborbicular to subtrigonal, convex or
depressed, thin, white. Surface smooth or sculptured with
fine growth lines, often minutely punctate or coarsely
granulose. Ligament external but sometimes becoming
partly immersed below the margin and attached to a
flattened nymphal plate. Hinge with two cardinal teeth
in each valve, of which the left anterior and the right
posterior tooth are typically double or bifid. Adductor
scars subequal in size and connected by an entire pallial
line which is often wide and ribbon-like. [ Olsson, Mol-
lusks of the Tropical Eastern Pacific (Paleo. Res. Inst.,
Ithaca, New York), p. 199, 1961).] Cretaceous to Recent.

Remarks. — As mentioned by Olsson, the subequal
muscle impressions (the anterior one longer and narrower)

252

and double cardinal teeth of the hinge, as well as anatomical
characters, are features in which the Diplodontidae differ
from the Lucinidae.

Chavan (758) recently discussed the classification
of this family. The subgenera Diplodonta s. s. and
Felaniella are each represented by one species in the San
Diego Formation.

GENUS DIPLODONTA BRONN

Diplodonta Bronn, Italiens Tertiar-Gebilde und deren
organische Einschltisse (Heidelberg), pp. IX, 96, p. XII
(as “Diglodonta”’ (typ. err.), 1831. [Concerning the
date of issue of this work see Bowden and Heppel,
Jour. Conch., Vol. 26, No. 2, p. 109, Note 4, 1966.]
Species cited: “D. lupinus nob. (Venus lupinus
Brocchi l.c.II.p. 553. Taff. XIV. fig. 8.) and “D
trigonula n. sp.”’ — Gardner, U. S. G. S., Prof. Paper
199-A, p. 79, 1943. Type as designated by Herr-
mannsen. — Eames, Phil. Trans. Roy. Soc. London,
Ser. B, No. 627, Vol. 235, p. 378, 1951. (With Synon.).
“Type species: Venus lupinus Brocchi, (non Linné). . .”
—Chavan, Bull. Inst. Roy. Sci. Nat. Belgique, Tome
38, No. 23, p. 8, 1962. Type as indicated by Herr-
mannsen, ‘‘ Venus lupinus Brocchi, 1814, (p. 553) non
Linné = Tellina rotundata Montague, 1803 (p. 77,
pl. Il, Fig. 3) = var. aequilateralis Ceruelli, 1909.”

Type species (designated by Herrmannsen, Indic.

Gen. Malacozoorum, Bd. 1, p. 392, 1846). — “Typus:

Venus lupinus Broce.” [Venus lupinus Brocchi, Conch.

Foss. Subapennina, Vol. 2, p. 553, pl. 14, fig. 8, 1814.

‘Abita nell’ Adriatico (Ren.). Fossile in Valle di Andonae

nel Piacentino.” Italy, Pliocene. Illustrated by Bronn,

Lethaea Geognostica, Bd. 3, p. 391, atlas, pl. 37, figs. 18a,

b, c, 1853-1856. — Woodward, Man. Moll., ed. 4 (reprint),

p. 458, pl. 19, fig. 9, 1910. “Miocene, Turin.”’ — Chavan,

1962, p. 8, fig. 3.]

Range. — Cretaceous to Recent. Recent, from the
intertidal zone to 1360 meters (744 fathoms).

Description. — Shell equivalve, not gaping, sub-
circular, the beaks subcentral and not prominent. Lunule
and escutcheon not defined. External surface smooth or
incrementally sculptured. Ligament chiefly external,
supported on marginal nymphs. Hinge of right valve armed
with a simple anterior and a bifid posterior cardinal; hinge
of left valve armed with a bifid anterior and a simple
posterior cardinal, so that in the closed valves the two
outer cardinals are simple, the two inner ones bifid.

Laterals absent. Adductor impressions oval, the anterior

longer and narrower than the posterior. Pallial line entire.

Inner margins of valves smooth. (Gardner, 1943.)

Remarks. — Nine species of Diplodonta have been
reported from strata of Tertiary age in California. Five
species have been recorded living in marine waters between

Bering Sea and San Diego, California, and eleven species

have been reported from tropical and subtropical west

American waters.

The genus is widespread and is represented by about

50 species in the seas at the present time. The greater

number of species occur in warm waters. Most of these

occur in quite shallow waters but at least one species,

Diplodonta (Felania) rosea Recluz, in the South Atlantic,

was reported by Thiele and Jaeckel to occur at a depth

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

of 155 meters. Lamy (759) published a paper dealing
with the Recent species of Diplodonta in the collections
of the Natural History Museum in Paris.

The genus name Taras Risso has been used by some
authors instead of Diplodonta Bronn. Prashad (760)
doubted that the type species of Taras, T. antiquata Risso,
is even a member of the family Ungulinidae [=Diplodon-
tidae] and Chavan (761) later discussed this question and
gave good reasons for abandoning usage of Taras in favor
of Diplodonta.

Key to Subgenera of Diplodonta (762)

A. Subglobose, nearly equilateral;
white. ; . Diplodonta s. s.
B. Compressed, inequilateral; usually

covered by a dark periostracum. Felaniella

SUBGENUS DIPLODONTA S. S.

Diplodonta (Diplodonta) orbella Gould
Plate 55, Figure 11; Plate 57, Figures 9, 18

Lucina orbella Gould, Proc. Boston Soc. Nat. Hist., Vol.
4, p. 90, November, 1851. — Gould, Boston Jour. Nat.
Hist., Vol. 6, p. 395, pl. 15, fig. 3 [two figs.], 1853.

Diplodonta orbella Gould, Cooper, Calif. State Min. Bur.,
Seventh Ann. Rept. State Mineral., p. 238, 1888. ‘“‘Pl.
—San Diego well.” — Arnold, Mem. Calif. Acad. Sci.,
Vol. 3, p. 134, pl. 18, figs. 8, 8a, 1903. (Lower San
Pedro series, Deadman Island), 1903. “‘Pliocene. — San
Diego well (Dall).” — I. S. Oldroyd, Publ. Puget Sound
Biol. Sta., Vol. 4, p. 38, pl. 3, fig. 4; pl. 25, figs. 5 and
6 (copy of Gould, 1853, pl. 16, fig. 3), 1924. Puget
Sound to the Gulf of California. [Not the record from
Bering Sea.] — I. S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 124, pl. 6, figs. 5, 6, 1924.
(Reproduction of figures by Gould, 1853). “Type
locality, San Diego, California.” “Range. Pribiloff
Islands to the Gulf of California.” [Not the record
‘*Pribiloff Islands.”’ ] — Haas,Field Mus. Nat. Hist., Zool.
Ser., Vol. 29, No. 1, pp. 8-12, figs. 3-7, 1943. La Jolla
and Terminal Island, San Pedro, California. Recent.

Taras orbellus Gould, Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 293, pl. 14, figs. 14a, 14b
(Recent), 1931. ‘‘San Diego well, Balboa Park, San
Diego (Dall).’’ Pliocene.

Type specimen. — No. 169271, Museum of Com-
parative Zoology, Harvard University (Johnson, U. S. Nat.

Mus., Bull. 239, p. 119, 1964).

Type locality. — “San Diego, Lieut. Green.”
[ California. ]
Range. — “cf.” Early Miocene; Pliocene to Recent.

Recent from Monterey, California, to Punta Penasco,
Sonora, Mexico, in the Gulf of California, from low tide
to 110 meters (60 fathoms), commonly nestling in holes
in rocks, sometimes embedded in a “‘nest”’ which it builds.

Occurrence in San Diego Fm. — San Diego well
(Cooper). L.A.M. 107, 305.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Original description. — T. parva, subglobosa, tenui-
cula, albida, concentrice inequiliter striata; apicibus medi-
anis, haud eminentibus, absque lunula antica; lateribus
fere symmetricis; intus alba. Cardo valvae dextrae dentibus
duobus quorum antico minore — valvae sinistrae dentibus
duobus quorum antico bifido, postico perobliquo, in-
structus; dentibus lateralibus nullis; cicatricibus leviter im-
pressis, palleali serie punctorum composito. Long. 4/5;
alt. 6/8; lat. 1/2-5/8 poll. (Gould.)

Remarks. — Chavan (763) suggested that the present
species might be referable to the subgenus Timothynus
Harris and Palmer (764), the type of which is a species of
late Eocene age.

Diplodonta orbella was cited by Cooper as occurring
in the collection from the San Diego well and this record
is apparently the basis upon which records from that
locality (referred to Dall) were cited by later authors.

Two casts retaining traces of shell are present in the
collection from Loc. 107 (LAM), the clay quarry at the
end of Arroyo Drive. The larger one is 19.8 mm long, the
convexity (one valve), 7.5 mm. The smaller one is 14.8
mm long. These agree so exactly in outline and convexity
with Recent and fossil specimens of Diplodonta orbella
that we identify them with that species.

Two right and one left valve, all incomplete, are
present in the collection from Loc. 305 (LAM). The
largest, a fragment of a highly convex right valve is 18.5
mm high.

A very large Recent specimen in the collections of
the California Academy of Sciences, collected by Henry
Hemphill at San Diego, California, is 34.5 mm long, 31.2
mm high, convexity (both valves together) 26 mm. They
are more often about 25 to 30 mm in length.

Haas (765) discussed the “nest” building habit of
this species by which it forms a protective covering of
sand and mucus.

Diplodonta orbella has been recorded as occurring
in beds of Pliocene age at other localitites than San Diego,
such as in the Pico and Merced formations. Diplodonta
griesensis Effinger (766) described from beds of middle
Oligocene age in western Washington was compared with
D. orbella and may be a precursor of Gould’s species.
“Diplodonta cf. orbella Gould” was cited by Loel and
Corey (767) from Vaqueros beds, early Miocene, and
Temblor strata, middle Miocene in age, and Bremner (768)
recorded it under the same heading (identification by
Corey), from Temblor beds on Santa Cruz Island,
California. Judging from the literature, there is an
element of doubt connected with many of the records of
D. orbella from pre-Pliocene strata. Khomenko (769)
cited the occurrence of D. orbella in Matchgar beds of
lower Miocene age on the Schmidt Peninsula on Kamtschat-
ka, but this identification appears doubtful. Records of
this species from Japan are referable to other species.

The exact northern range of Recent Diplodonta
orbella is not known with certainty. We have not
observed Recent specimens from north of Monterey,
California. Some of the Alaskan shells formerly referred
to this species are referable to Diplodonta impolita Berry
(770). We have observed specimens of this species from
as far south as Cordell Bank (Lat. 38° N.), west of Point
Reyes, California, in 40 meters (22 fathoms). Diplodonta
impolita differs from D. orbella in the narrower, less in-
flated and more pointed umbos, more steeply sloping

253

anterior dorsal margin, earthy texture and coarser in-
ecremental striae. Also the right anterior cardinal is
vertically elongated in comparison to the analogous some-
what node-like tooth on Gould’s species. Another
northern form was described as Diplodonta (Torelli
Jeffreys, var.?) aleutica by Dall (Proc. U.S. Nat. Mus.,
Vol. 23, p. 820, pl. 42, fig. 3, August 22, 1901) from
Kyska Harbor, Aleutian Islands, in 8 fathoms.

SUBGENUS FELANIELLA DALL

Felaniella Dall, Jour. Conch., Vol. 9, No. 8, p. 244, Octo-
ber 1, 1899. “Type Felania usta Gld.” — Lamy, Jour.
de Conchyl., Vol. 65, No. 4, p. 338, 1921. “Type:
D. usta Gould.’”’ — Habe, Gen. Jap. Shells, Pelecypoda,
No. 2, p. 124, 1951. ‘“‘Type species: Felania usta
Gould (original designation)’, figs. 256, 257.

Type species (by original designation). — Felania
usta Gould [=Mysia (Felania) usta Gould, Proc. Boston
Soc. Nat. Hist., Vol. 8, p. 31, March, 1861. ‘“Inhabits
Hakodadi Bay, in sandy mud, 8 fath.’’ — Taki and Oyama,
Paleo. Soc. Japan, Spec. Paper No. 2, p. 57, pl. 10, figs.
14-16; pl. 33, fig. 2, 1954 (as Diplodonta (Felaniella)
usta). Japan. Pleistocene. — Kira, Col. Illus. Shells of
Japan, p. 132, pl. 52, fig. 31, 1959 (as Felaniella usta.)
Japan, Recent. — Chavan, Bull. Inst. Roy. Sci. Nat.
Belgique, Vol. 38, No. 23, p. 10, 1962. Type: Felania
usta Gould. Illustrated by Chavan, fig. 8. — Johnson,
U. S. Nat. Mus., Bull. 239, p. 164, pl. 26, fig. 6, 1964 (as
Mysia (Felania) usta.) Holotype].

Range. — Late Cretaceous to Recent (Chavan).
Recent from the intertidal zone to 218 meters (119
fathoms).

Description. — Shell small, very inequilateral,

slightly inflated; sculpture consisting of incrementals;
ligament external; hinge of right valve consisting of a
narrow anterior cardinal (3a) and a heavy, deeply bifid
middle cardinal (3b); hinge of left valve consisting of a
heavy, deeply bifid anterior cardinal (2) and a narrow
posterior cardinal (4b). (Woodring, Carnegie Inst. Wash-
ington, Publ. No. 366, p. 130, p. 130, 1925.)

Remarks. — The shells of this subgenus differ from
those of Diplodonta s. s. in that they are more com-
pressed, less equilateral and in the Recent state they are
covered with a dark periostracum.

Felaniella has been reported to range from Paleocene
to Recent but in the western Americas it has not been
reported earlier than in strata of Oligocene age (Tumey
Sandstone). Most of the Recent species live in the Carib-
bean region and in the warmer waters of the eastern
Pacific, but species also live in Japanese waters and one
has been reported from South Africa.

Diplodonta (Felaniella) cornea Reeve
Plate 43, Figures 7, 13, 20

Lucina cornea Reeve, Conch. Icon., Vol. 6, Lucina,
species 25, pl. 9, fig. 25, June, 1850.
Lucina nitens Reeve, Conch. Icon., Vol. 6, Lucina, species

50, pl. 9, fig. 50, June, 1850. ‘‘Hab. Isle of Muerte,

254

Bay of Guayaquil (in sandy mud at a depth of about
eleven fathoms); Cuming.”

Lucina sericata Reeve, Conch. Icon., Vol. 6, Lucina,
species 55, pl. 9, fig. 55, June 1850. “Hab. — ?” —
Adams and Reeve, Zool. Voy. Samarang, Moll., p. 80
p. 24, fig. 6, August, 1850. ‘Hab. Philippine Archi-
pelago.”’ [Locality believed to be erroneous. ]

Diplodonta sericata Reeve, Woodring, Bramlette, and Kew,
U. S. G. S., Prof. Paper 207, p. 83, pl. 36, figs. 11-14,
1946. Palos Verdes sand, San Pedro, California,
Pleistocene.

Taras (Felaniella) sericatus Reeve, Hertlein and Strong,
Zoologica, Vol. 31, Pt. 4, p. 131, pl. 1, fig. 10, 1947.
“San Ignacio Lagoon, Lower California, to Guayaquil,
Ecuador,” Recent. [With synonymy. |

Diplodonta (Felaniella) sericata Reeve, Keen, Sea Shells of
Tropical West America (Stanford Univ. Press: Stanford,
California), p. 103, fig. 212, 1958. San Ignacio Lagoon,
Lower California, to Ecuador.

Diplodonta (Felaniella) cornea Reeve, Olsson, Mollusks of
the Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), p. 203, pl. 32, figs. 1, la, 1b, 1961. Gulf
of California to Tumbez, Peru.

Type specimen. — Syntypes No. 1963 130/1-2,
British Museum (Natural History).

Type locality. — ““Hab. Gulf of Nicoiya (in coarse
sand at a depth of from ten to thirteen fathoms);
Cuming.’ Costa Rica.

Range. — Middle Pliocene to Recent. Recent from
San Ignacio Lagoon, Lower California, to Punta Penasco
in the Gulf of California, Mexico, and south to Tumbez,
Peru, in 7 to 73 meters (4 to 40 fathoms). ,

Occurrence in San Diego Fm. — L.A.M. P. 87:
$8443, 305.

Original description. — Shell Cardium-shaped, a little
higher than long, rather depressed, no lunule, concentric-
ally impressly striated, hinge with two central teeth in
each valve, one of which is bifid; whitish, covered with a
light olive shinning horny epidermis. (Reeve.)

Remarks. — Four small, right valves and one left
one, are present from Loc. 305 (LAM), near the Mexican
boundary. The left valve is 10.5 mm long and 10.8 mm
high. None of these valves is perfectly preserved but they
agree in all observable details with Recent specimens of
D. cornea of the same size. A fragment of a valve from
the same locality, 17 mm long may be referable to this
species.

One small right valve, slightly imperfect along the
anterior margin, collected by Charles Sternberg in Balboa
Park, is 11.5 mm long and 10.5 mm high.

A large Recent left valve from Loc. 27230 (CAS).
Petatlan Bay, Mexico, is 22.6 mm long and 22.3 mm high.
A specimen with paired valves from Loc. 23796 (CAS)
Tepoca Bay, Gulf of California, is 20.5 mm long 20.2
mm high, convexity (both valves together 9.6 mm.
Another more convex specimen from the same locality is
19.2 mm long, 19.4 mm high, convexity (both valves to-
gether) 10.3 mm.

Diplodonta cornea is here reported for the first time
from the San Diego Formation. It was reported (as
Diplondonta sericata) by Emerson and Hertlein (Trans. San
Diego Soc. Nat. Hist., Vol. 13, No. 17, pp. 342, 349,
1964) from strata of Pliocene age on Carmen Island in the
Gulf of California. It is well known from beds of

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Pleistocene age in southern California and in Lower Cali-
fornia and it has been reported (771) as a fossil from an
elevated beach in Peru.

This species is generally recorded under the name
Diplodonta sericata Reeve. Hertlein and Strong pointed
out that D. cornea has page priority and this nomen-
clature was also adopted by Olsson. Furthermore D.
sericata was originally described without information as to
the locality from which it came. Later Adams and Reeve
cited it from the Philippine Islands. Finally Carpenter
and Dall, considered it to be a west American species.
After consideration of the history of this species we con-
clude that it is best to use the earliest name applicable to
this form.

The present species is very similar to Diplodonta
parilis Conrad (772), described from Oregon in beds of
middle Miocene age. Some authors have recorded D.
cornea (as D. sericata) as a subspecies of D. parilis.

A series of specimens of D. parilis trom Miocene
strata at Loc. 166 (CAS), Clatskanie, Oregon, and casts of
the specimens from the Astoria Formation in western
Washington which were illustrated by Etherington (773),
are all slightly more elongated anteriorly-posteriorly and
the ends are a little more flattened that are those of D.
cornea. Some specimens from beds of late Pliocene age in
San Joaquin Valley appear to be inseparable from D.
cornea, others are hardly separable from D. tellinoides
Reeve (774).

Diplodonta harfordi Anderson (775) described
from beds of probable middle Miocene age in San Joaquin
Valley has a straighter anterior dorsal margin than either
D. parilis or D. cornea.

Diplodonta stephensoni Clark (776), described from
the San Ramon Formation of late Oligocene or early
Miocene age, near Walnut Creek, California, was said to
differ from D. “‘serricata” [= D. cornea] in details of the
hinge.

Diplodonta candeana d’ Orbigny, originally described
from Cuba, also is similar to D. cornea. Chavan (1962, p.
12) mentioned a resemblance between D. ‘“‘sericata”
[=D. cornea] and species in the subgenus Zemysia Finlay,
1927, with the type Z. zelandica Gray, 1835.

FAMILY THYASIRIDAE DALL (777)

Shell roundly trigonal, earthy, thin; posterior side
with one or more radial depressions; ligament in a groove,
partly external, hinge edentulous or in the right valve with
a subobsolete pseudo-tooth; muscle impressions elongated;
pallial line simple; margin smooth. Triassic (Chavan).
Cretaceous to Recent.

Remarks. — This family is represented in the eastern
Pacific by Thyasira and Axinopsida. One species of each
is present in the San Diego Formation.

The greater number of species in this family live in
boreal waters but a number of species are found in tropical
waters.

The genus Adontorhina Berry (778) was placed
tentatively, in the family Thyasiridae. However, the lack
of a posterior radial depression, the hinge with ridged
plates, and the granular or plated posterior dorsal margin,
are shell characters differing from other members of this
family.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Key to Genera of Thyasiridae

A. Shell with one or more furrows

on posterior portion . Thyasira
B. Shell discoidal, lacking furrows
on posterior portion j . Axinopsida

GENUS THYASIRA LEACH IN LAMARCK

Thyasira Leach in Lamarck, Hist. Nat. Anim. s. Vert., Vol.
5, p. 492, July, 1818. Sole species cited, ““Thyasira
flexuosa. Leach.” Ref. to “‘Tellina flexuosa. Maton
Act. Soc. Linn. 8. p. 56, n. o. 16.” — Dall, Trans. Wag-
ner Free Inst. Sci., Vol. 3, Pt. 4, Pt. 6, p. 1335, October,
1903. Sole species originally cited, Tellina flexuosa
Montagu. — Lamy, Jour. de Conchyl., Vol. 65, No. 3,
p. 290, 1921. Type, Tellina flexuosa Montagu. Fig.
(p. 291).

Conchocele Gabb, Geol. Surv. Calif., Palaeo., Vol. 2, p.
27, February, 1866. Type (by virtual monotypy):
Conchocele disjuncta Gabb, p. 28, pl. 7, figs. 48, 48a,
48b. “From Dead Man’s Island, near San Pedro Bay;
from a hard sandstone associated with two or three
previously known Tertiary Fossils. Probably Miocene.”
[Late Pliocene or early Pleistocene.] [Venus bisecta
Conrad mentioned in the text was considered as
“probably belonging to this genus.’’ This equivocal
statement leaves C. disjuncta as the sole species
available as type of the genus according to the present
rules of nomenclature. For a discussion of this species,
see Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ.
No. 3, p. 194, pl. 15, fig. 1, 1930. — Woodring,
Bramlette, and Kew, U.S. G. S., Prof. Paper 207, p. 83,
pl. 33, fig. 5, 1946. “T. disjuncta is the type of
Conchocele.”’ |

Type species (by monotypy). — Thyasira flexuosa

Montagu [=Tellina flexuosa Montagu, Test. Brit., p. 72,

1803, “It is plentiful in the sand of Falmouth harbour,

and not uncommon on the south coast of Devonshire.”

Also, ‘‘Cornwall”’. Illustrated by Forbes and Hanley,

Hist. Brit. Moll., Vol. 2, p. 54, pl. 35, fig. 4, 1852. —

Jeffreys, Brit. Conch., Vol. 2, p. 247, pl. 5, fig. 6, 1863;

Vol. 5, pl 179, p. 33, figs. 1, 1a, 1869. — Thiele, Hand-

buch Syst. Weichtierkunde, Bd. 2, p. 864, 1935. See also

Lamy, 1921, p. 292, fig. p. 291; Tebble, British Bivalve

Shells [ Brit. Mus. (Nat. Hist.)]. pp. 16, 79, text-fig. 5a,

5b, 1966. |

Range. — Cretaceous to Recent. Recent world wide
from low tide to 10,004 meters (5470 fathoms) (779.)

Description. — Shell subcircular to subquadrate,
moderately inflated, beaks strongly curved anteriorly;
lunule consists of an impressed area below the beaks
sometimes indistinct, escutcheon long and narrow;posterior
side furrowed or sharply angulated; ligament usually
partly external; sculpture of growth lines only; hinge
lacking teeth but sometimes below the umbo of the left

valve there is a fold in the hinge plate and behind this a

slight projecting pseudo-tooth; muscle impressions luci-

noid; pallial line simple; margins smooth.
Remarks. — The genus Thyasira occurs in western

North America in strata of Cretaceous age and from

259

Oligocene to Recent, but no species have been described
from beds of Eocene age in this region. One species has
been recorded as occurring in the San Diego Formation.
Popenoe (780) cited the occurrence of casts of ‘‘Thyasira”
in brown, calcareous, silty sandstone dredged apparently
on “Coronado Bank”. Nothing further is known con-
cerning the species represented by the casts or the age of
the strata containing them.

This genus is represented by a number of Recent
species and is widespread in the seas at the present time,
mostly in cool waters. Many of the species are small or
of moderate size, but a specimen of T. disjuncta collected
by G. D. Hanna on the shore of Macleod Bay, Montague
Island, Alaska, is 85 mm long, 69.5 mm high, and the
convexity (both valves together) 55.4 mm. Hagg (781)
cited a fossil form identified as Thyasira bisecta from
beds of late Tertiary age in Spitzbergen, the largest of
which was 85 mm long. Judging from the known records
of size, Hagg concluded that this species attained a larger
size in warmer rather than in very cold waters.

Most of the known living species of Thyasira were
discussed or listed by Lamy (1921, pp. 289-318). Dall
(782) mentioned nine species living in the eastern Pacific.
A monographic study of this group would probably result
in a reduction of this number. The Recent species living
in New Zealand were given special attention by Fleming
(783) who place Prothyasira Iredale, 1930, in the syn-
onymy of Thyasira. Antarctic species of this genus were
discussed by Soot-Ryen (784). The Cenozoic species of
Thyasira occurring in Japan were discussed by Yabe and
Nomura (785) and species from the beds of Tertiary age
in Sakhalinand Kamtschatka were described and illustrated
by Slodkewitsch (786). Species of Thyasira of Cretaceous
age from the western interior of North America were des-
cribed and illustrated recently by Kauffman (787). In
this paper he included a general discussion of this genus
and its occurrence both Recent and as a fossil.

Thyasira gouldii Philippi
Plate 43, Figures 17, 21

Lucina flexuosa Montagu, Gould, Rept. Invert. Massa-
chusetts (Cambridge), p. 71, fig. 52, 1841.

Not Tellina flexuosa Montagu, Test. Britannica; or Nat.
Hist. British Shells, Pt. 1, p. 72, 1803. ‘Cornwall’;
also “‘in the sand of Falmouth harbour” and “south
coast of Devonshire.”

L[ucina]. Gouldii Philippi, Zeitschr. f. Malakozool.,
Jahrg. 2, p. 75, May, 1845. [Description pp. 74-75.
In a review of Gould’s Report on the Invertebrata of
Massachusetts. |

Cryptodon Gouldii Philippi, Binney’s edit. of Gould’s
Rept. Invert. Massachusetts (Wright and Potter: Bos-
ton), p. 100, fig. 52, 1870. Massachusetts Bay and
neighboring region.

Cryptodon flexuosus Montagu, Dall, Proc. Calif. Acad.
Sci., Vol. 5, p. 297, 1874. ‘well at San Diego,”
“Pliocene.” — Dall, Proc. U. S. Nat. Mus., Vol. 1, p.
28, 1878. San Diego well. — Cooper, Calif. State Min.
Bur., Seventh Ann. Rept. Calif. State Mineral., p. 237,
1888. “San Diego well.’’ — Orcutt, West Amer. Sci.,
Vol. 6, whole No. 46, p. 85, 1889. Dall’s record

256

(1874) cited. — Orcutt, quoted by Ellis in Ellis and Lee,
U. S. G. S., Water Supply Paper 446, p. 59, 1919.
Dall’s record (1874) cited.

Not Cryptodon flexuosus Montagu
Montagu, 1803].

Axinus gouldii Philippi, Sars, Bid. Kundsk. Norges
Arktiske Fauna I, Moll. Reg. Arct. Norvegiae (Christ-
iana) p. 60, pl. 19, figs. 6a, 6b, 1878. Various localities
in northern Atlantic.

Thyasira gouldii Philippi, Dall, Proc. U. S. Nat. Mus., Vol.
23, No. 1237, pp. 786, 790, 1901. Greenland to
Stonington, Connecticut, in 5 to 400 fathoms; on west
coast from Metchigme Bay, Bering Strait, south to
Puget Sound, in 8 to 11 fathoms. Also Pliocene of San
Pedro, California. — I. S. Oldroyd Publ. Puget Sound
Biol. Sta., Vol. 4, p. 37, pl. 42, fig. 5, 1924. “Bering
Sea to San Diego, Calif.; Atlantic.” [Reproduction of
figure from Packard, 1918.] —I.S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 120, pl. 34,
fig. 5 (Recent), 1924. ‘Pliocene at San Diego well.”
Also other localitites. — Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 282, 1931. “San
Diego formation of the San Diego well in Balboa Park.
San Diego (Dall, 1874). — Hertlein and Grant, Mem.
San Diego Soc. Nat. Hist., Vol. 2, Pt. 1, p. 48, 1944.
Dall’s record (1874) of Cryptodon flexuosus Montagu.
— Morris, Field Guide to Shells (Houghton Mifflin Co.:
Boston) p. 36, pl. 8, fig. 15, 1952. ‘“‘from the Bering
Sea to San Diego, California.” — Ockelmann, Mar.
Lamell., in Zool. East Greenland, Medd. om Grd@nland
Vol. 122, No. 4, p. 100, pl. 2, figs. 4, 5,1958. East
Greenland and other localities in 2-3 to 385 meters
Panarctic.

Thyasira gouldi Philippi, Arnold, Mem. Calif. Acad. Sci.,
Vol. 3, p. 1386, 1903. ‘San Diego well (Cooper).” —
Packard, Univ. Calif. Publ. Zool., Vol. 14, No. 2, p.
264, pl. 20 fig. 5, 1918. ‘‘Bering Strait to San Diego
(Dall).”

Type specimen. — Reported to be in the State
Museum, Albany, New York, by I. S. Oldroyd, 1924, but
according to R. I. Johnson (written comm., October 27,
1964), no specimens of this species were found in any of
Gould’s collections examined by him.

Type locality. — “It inhabits deep water, and is very
frequently taken from codfish, caught in Massachusetts
Bay.” (For “Lucina flexuosa” Montagu of Gould, 1841,
not Tellina flexuosa Montagu, 1803.)

Range. — Pliocene to Recent. Recent from Bering
Strait to San Diego, California, in 15 to 203 meters (8 to
111 fathoms). Atlantic from Greenland to Connecticut,
in 9 to 732 meters (5 to 400 fathoms) Dall (1901); to
North Carolina (Richards). According to Ockelmann
(1961), this species “is uncommon at depth exceeding
100 m and even depths of about 50 m often only smaller
specimens are found.”

Occurrence in San Diego Fm. — San Diego well
(Dall). L.A.M. 107, 305, 805A. U.C.L.A. 294.

Original description. — “Von Lucina flexuosa sagt
Gould, p. 72: ‘there can be no doubt, that this is identical
with the British shell, though the specimens I have seen are
much smaller, than the foreign specimens usually are’.
Bei einer aufmerksamen Betrachtung findet man idessen,
ausser dem sehr auffallenden Unterschied in der Grosse —
die amerikanische Art ist 1 1/2” , die englische 4’”’ gross

[=Tellina flexuosa

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

— folgende Verschiedenheiten: 1) die amerikanische Art
ist schiefer, die hintere Seite, welche die beiden Falten
tragt, kuirzer; 2) dieselbe hat keine vertiefte Lunula, und
ist namentlich der Schlossrand vorn nicht gerade oder
selbst concav, sondern von Anbeginn an convex; dagegen
geht 3) eine breite seichte Furche nach dem vordern
Winkel hin, von der die englische Art keine Spur zeigt. Ich
schlage vor, die amerikanische Art L. Gouldii zu nennen.
Sie gehort tbrigens in das Sowerby’sche Genus Axinus,
welches mit dem Turton’schen Genus Cryptodon identisch
ist, so wie mit dem von mir aufgestellten Genus Ptychina”’.
(Philippi.)

Remarks. — This species was reported from the San
Diego well by Dall in 1874. Subsequent records citing it
from that locality apparently were based upon Dall’s
record. Seven fairly well preserved specimens in the col-
lections of the University of California at Los Angeles,
and a few others, mostly fragmental, in the collections of
the Los Angeles County Museum, are from the San Diego
Formation from near the Mexican boundary. The largest
specimen from Loc. 294 (UCLA) is 9.4 mm long and
8 mm high. A Recent large left valve from Winter
Harbor, British Columbia, in the collections of the
California Academy of Sciences, is 9.6 mm long and 10.1
mm high.

These fossils appear to be identical with specimens
of Thyasira gouldii from the Atlantic coast. Dr. A. M.
Keen compared the fossils with Recent shells in the col-
lection at Stanford University and concluded that T.
gouldii could be considered to be a subspecies of the
north European T. flexuosa Montagu. This was virtually
the same opinion as that of Odhner (788) who noticed
minor differences between the European species and
specimens of T. gouldii from Alaska. The shell of the
European species was said to be more fragile and white in
comparison to Alaskan specimens of T. gouldii which
were rougher, thicker and of a dirty white color.

The name Lucina gouldii was proposed by Philippi
in 1845 (for “Lucina flexuosa” Montagu, described and
illustrated by Gould) in a review of Gould’s paper dealing
with the Invertebrata of Massachusetts, 1841.

Binney (1870) stated that Philippi’s criteria for
separating T. gouldii from the European T. flexuosa are
valid, namely, ‘“‘ours is much smaller, more oblique, the
hinder end on which the folds are situated is shorter, the
lunule is less deep, and the anterior margin is not concave,
but rather convex. Indeed the disparity in size is so great
as scarcely to suggest a comparison.”

A study of north Atlantic and Arctic species of
Thyasira led Ockelmann (789) to believe that the east
American forms described a Cryptodon plana Verrill and
Bush (791) “‘must be regarded as junior synonyms of T.
gouldii (Philippi). Eyerdam’s record of T. gouldii from
Dryer Bay, Alaska, was later corrected to T. cygna Dall
(792). The species from Japan cited under the name of
Thyasira gouldii was named Thyasira tokunagai by Kuroda
and Habe (793). According to Habe (794) the Japanese
shell is smaller and has a narrower posterior flexure.

The group of Thyasira flexuosa (to which T.
gouldii belongs) has been reported from Miocene to
Recent in Europe. This group is widely distributed in the
seas at the present time. Cryptodon marionensis E. A.
Smith (795) from the Antarctic region was said by its
author to be a southern form of T. flexuosa and T.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

gouldii. Fleming (1950, p. 251) in his discussion of the
Austral species, T. peroniana, stated: “‘It is indeed pos-
sible to consider peroniana and its races as subspecies of
the wide-ranging flexuosa Mont.”

Thyasira gouldii has been cited as occurring at
several localities in beds of Pliocene age in southern
California. Some of these occurrences are as follows:
Potrero Canyon, 1/4 mile south of the Palisades post
office, by Woodring (796); at Fourth and Broadway in
Los Angeles by Soper and Grant (797); questionably at
the Waldorf Asphalt Mine in the Foxen Mudstone in the
Santa Maria district by Woodring (798). Woodring men-
tioned that the anterior end of specimens from that dis-
trict is longer than on Recent specimens from California.
Thyasira gouldii also has been recorded occurring in
Pleistocene beds in California and Richards (799) has
recorded it from beds of Pleistocene age in Maine, in
Vermont,in Montreal, in Quebec, and in Newfoundland.

Valentine (800) considered T. gouldii to be a member
of a “Lucinoma annulata-Turcica caffea community” in
beds of Pleistocene age in southern California, deposited
probably at a depth of 27 to 46 meters (15 to 25
fathoms). A “Thyasira gouldii-Neptunea tabulata” com-
munity is said to live in the “shallow outer sublittoral,
20-25 fathoms, silt and clay bottom.”

Thyasira barbarensis Dall (801) appears to be quite
distinct from T. gouldii. At the time of description of T.
barbarensis Dall stated, ‘“‘This fine species is nearer C.
sarsii [802] than any other, but has decidedly more
elevated and narrower beaks.’’ He also included a descrip-
tion of the soft parts of his new species. Burch mentioned
that T. barbarensis usually lives in colonies and Valentine
(1961, p. 323) stated that it was found rather commonly
on a mud bottom in 38-40 meters (21-22 fathoms) in
Santa Monica Bay in southern California.

GENUS AXINOPSIDA KEEN AND CHAVAN

Axinopsis Sars, Bid. Kunds. Norges Fauna. I. Moll.Reg.
Arcticae Norvegiae (Christiana), p. 63, 1878. Sole
species, Axinopsis orbiculata Sars.

Not Axinopsis Tate, 1868, a new name for Schizodus
King, 1844.

Axinopsida Keen and Chavan, in Chavan, Compt. Rend.
Somm., Soc. Geol. Franc, No. 12, p. 210, June 18,
1951. “Type: A. orbiculatus Sars.” — Keen, Min.
Conch. Club South. California, No. 116, p.4, December
1951. “Type (by original designation): A. orbiculatus
(Sars).””

Type species (by original designation). — ‘‘Type:

A, orbiculatus Sars” [=Axinopsis orbiculata Sars, 1878,

p. 63, pl. 19, figs. lla-d, ‘“‘Vadsé paa 600-100 F. D.”

Also, from Vard@ and Bod¢, Norway. — Soot-Ryen, Norges

Svalbard — og Ishavs — Unders@kelser, Medd. No. 43, p.

14, pl. 1, fig. 7, 1939. “Off East glacier, Cape Flora, 4

fathoms,” and ‘Gunther Sound (Bay), 10 fathoms,”

Franz Josef Land. — Ockelmann, Medd. om Grégnland,

Bd. 122, No. 4, p. 111, pl. 2, figs. 7, 8, 1958. East Green-

land and other localities. — MacGinitie, Proc. U. S. Nat.

Mus., Vol. 109, No. 3412, p. 172, pl. 20, fig. 2, 1959.

Pt. Barrow, Alaska, in 36 meters (120 feet). ]

Range. — Middle Pliocene to Recent. Recent,

257

Arctic to Todos Santos Bay, Lower California, Mexico,
and to Japan; Norway and Greenland to Cape Hatteras,
North Carolina, in Atlantic; Antarctic, in 7 to 594 meters
(4 to 325 fathoms). Cited from depths of 10,607 meters
(5850 fathoms).

Description. — Shell discoidal, tumid in the middle,
compressed towards the margins; umbones slightly promi-
nent; no external ligament; valves thin, pellucid, white,
concentrically striate; cardinal tooth in the right valve
obtusely elevated, recurved, in the left valve elongated,
subhorizontal; cartilage narrow. (For Axinopsis. Tryon,
G. W., Jr., Structural and Systematic Conchology, Vol. 3,
p. 216, 1884.)

Remarks. — The members of this genus live chiefly
in Arctic and boreal waters but in the eastern Pacific this
genus occurs south to Todos Santos Bay, Lower California,
Mexico.

The shells of Axinopsida are small. The number of
described species and subspecies is not large but the
separation of the various forms has not been entirely
satisfactory.

Genaxinus Iredale, type Thyasira albigena Hedley, is
a similar genus but the hinge of species of this austral
group is virtually edentulous (803).

Axinopsida serricata Carpenter
Plate 44, Figures 17, 18

Cryptodon serricatus Carpenter, Rept. Brit. Assoc. Adv.
Sci. for 1863, pp. 602, 643, issued August, 1864. Re-
print in Smithsonian Mise. Coll., No. 252, pp. 88,
129, 1872. Indicated as from ‘‘Puget’s Sound and the
neighbourhood”’; ‘Vancouver Island, Straits of S. Juan
de Fuca, and adjoining shores of Washington Territory,
formerly known as ‘Oregon’.’’ Also ‘“?Cat. Is. Cp. 120
fm.’’ — Carpenter, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 17, p. 57, 1865. “Hab. — In sinu Pugetiano legit
Kennerly: in insula Vancouver, Swannii Indianuli.”

Axinopsis sericatus Carpenter, Dall, Proc. U. S. Nat. Mus.,
Vol. 23, No. 1237, pp. 791, 819, pl. 40, fig. 2 (Puget
Sound), 1901. ‘‘Kyska Island, Aleutians, south to
Puget Sound and Catalina Island, California, in 2 to
120 fathoms.” — I. S. Oldroyd, Publ. Puget Sound
Biol. Sta., Vol. 4, p. 38, pl. 26, fig. 4, 1924. Puget
Sound; Departure Bay, British Columbia. Range:
Aleutian Islands, Alaska, to Catalina Island, California.
— I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol.
Sci., Vol. 1, p. 123, pl. 4, fig. 4, 1924. Range same as
in preceding reference.

Axinopsida serricata Carpenter, K. V. W. Palmer, Geol.
Soc. Amer., Mem. 76, p. 84, pl. 7, figs. 16-18, 1958.
“Puget Sound, Washington (type).” Range same as given
by Dall.

Type specimen. — “‘Lectotype. — U. S. National
Museum, No. 5249” (Palmer, 1958.)

Type locality. — ‘“‘Puget Sound, Washington (type).”
(Palmer, 1958.)

Range. — Middle Pliocene to Recent. Recent from
the Aleutian Islands, Alaska, to Todos Santos Bay, Lower
California, in 4 to 219 meters (2 to 120 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A.

Original description. — Small, circular, flat; epider-

258

mis silken. (Carpenter.)

Supplementary description: C. t. parva, subplanata,
subcirculari tenui, alba, haud flexuosa; epidermide
tenuissima, vix straminea, serricata, induta; laevi, seu
lineis incrementi vix ornata, nitente; suborbiculari, seu
ventraliter producta; marginibus undique valde et regular-
iter rotundatis, regione lunulari incurvata; umbonibus
attice hamatis; lunula planata, haud exacte difinita; intus,
ligamento tenui, omnino celato; dentibus cardinalibus in
utraque valvé uno, extante, lateralibus nullis; cicatricibus
adductoribus subovalibus, haud prolongatis; linea palii a
margine ahud crenato satis remota: Long. .16, lat. .18,
alt. .1 (Carpenter, 1865.)

Remarks. — Three left and one small right valve of
this species are present in the collection from Loc. 305
(LAM) from near the Mexican boundary. The largest of
these, a left valve, is about 3.4 mm long and 3.1 mm high.
The small right valve is higher than long. One right and
two fragmental left valves are present in the collection
from Loc. 305A (LAM).

The lectotype was described by Palmer as slightly
higher than long, about 4.5 to 4 mm. Burch (804)
questioned whether Axinopsis viridis Dall (805) could
be separated from A. serricata. Dall illustrated two shells
under these names and described A. serricata as “ovate”
and A. viridis as “‘orbicular.” Willett (806), and Woodring
evidently believed that they could separate the two species
on the basis of shape. Palmer (1958) however, pointed
out that Carpenter originally described A. serricata as
“circular.” Furthermore in various collections she found
specimens, some of which were round, others elongate,
which were identified in some cases as Axinopsis viridis
Dall and in others A. serricata. Z

We have examined Recent specimens from Alaska,
Puget Sound, Monterey, and Redondo Beach, California.
Most of these are circular in outline. A large one from
Loc 18545 (CAS), Unalaska, is 3.9 mm long and high.
Dall and others have indicated that the geographic ranges
of A. serricata and A ovata are nearly the same. We are
inclined to share the doubts of Burch and Palmer that
more than one species of Axinopsida lives in the north-
eastern Pacific.

Axinopsida serricata was reported by Willett (807)
from strata of late Pliocene age at Fourth and Broadway
streets in Los Angeles; in the Lomita Marl, Hilltop Quarry,
Los Angeles Co. (Valentine and Mead), and it also has been
reported from beds of Pleistocene in age in British
Columbia (808). Axinopsida viridis Dall was reported by
Woodring (809) from the Waldorf asphalt mine in Santa
Barbara Co. That species also has been reported from beds
of late Pliocene age in Los Angeles Co. as well as in beds
of Pleistocene age in Alaska, and at San Pedro, California.

SUPERFAMILY CARDIACEA OKEN (810)
FAMILY CARDIIDAE OKEN (811)

Shell substance cellulo-crystalline, with the external
layer more or less tubular; with a variable epidermis; valves
equal free, gaping slightly behind, the beaks prosocoelous,
the margins usually serrate or radially straited; adductor
scars subequal, the pedal distinct and usually distant;
ligament and_ resilium parivincular, external, set in a
groove, short; area obscure; the complete armature of the
hinge includes an anterior and posterior lateral in the left,

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

and two anterior and one posterior lateral in the right

valve (any or all of which may be absent), the cardinal

formula is L 1010, the teeth simple, smooth never bifid,
R 0101

one cardinal in each valve usually persistent, the others

inconstant. (Dall, Trans. Wagner Free Inst. Sci., Vol. 3,

Pt. 3, p. 549, 1895.). Late Triassic to Recent.

Remarks. — The members of this family are world-
wide in distribution from the Arctic to the tropics in
marine and in brackish water. A number of supraspecific
units have been proposed for the members of the Cardiidae.
These together with their type designations have been
assembled in a paper by A. M. Keen (812)

Various papers concerning Cenozoic species of this
family have been published. Among the more recent ones
may be mentioned one by Marwick (813) dealing with
the species of New Zealand, one by Tremlett (814) dealing
with English Eocene and Oligocene species, and one by
Sieber (815) dealing with Miocene species in the Vienna
basin.

A synopsis of Recent west American species was
published by Dall (816), and Hertlein and Strong (817),
Keen (818), and Olsson (819) discussed many of the
Recent tropical west American species. Notes by Burch
(820) and others on the species occurring in the region
between the Bering Sea and San Diego, California, occur
in the Minutes of the Conchological Club of Southern
California. A useful paper dealing with the species of
Cardiidae living in the west Atlantic region was published
by McLean (821).

Key to Genera and Subgenera of Cardiidae

A. Shell large, with coarse radial ribs with
roughly uniform secondary sculpture.
a. Beaks strongly prosogyrate Clinocardium
aa. Beaks not prosogyrate or only
slightly so.

b. Ribs lacking
nodes (subgenus) Cardium s. s. (822)
bb. Ribs in central portion bear
elongated nodes on posterior and
sometimes to a lesser degree on
anterior side (subgenus) Dallocardium

B. Shell small to moderate size, with
rather fine radial ribs of which those on
posterior fourth of valves differ in
secondary sculpture . . Nemocardium

a. Posterior ribs decidedly wider than
the others . . (subgenus) Nemocardium s. s. (822)
aa. Posterior ribs not decidedly
wider than the others and
crossed by concentric

lamellae (subgenus) Keenaea

GENUS CARDIUM LINNAEUS

Cardium Linnaeus, Syst. Nat., ed. 10, p. 678, 1758.
Cardium costatum Linnaeus, first of a number of

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

species described by Linnaeus. — Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 5, p. 1069, December, 1900.
Earlier authors cited. — Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 302, 1931. Type
(designated by Children): Cardium costatum Linnaeus.

Type species (designated by Children, Quart. Jour.
Sci. Lit. Arts, Vol. 14, p. 315, pl. 6, fig. 59, 1823). —
Cardium costatum Linnaeus [Syst. Nat., ed. 10, p. 678,
1758. “Habitat.... Ref. to Rumphius, Mus., pl. 48, fig.
6; Gaultieri, Test., pl. 72, fig. D; Argenville, Conch., pl. 26,
fig. A, and “Column. purp. 26, t. 27.” Illustrated by
Reeve, Conch. Icon., Vol. 2, Cardium, sp. 11, pl. 2, fig.
11, 1844. ‘‘ Hab. East Coast of Africa.’’ See discussion
of this species by Dodge, Bull. Amer. Must. Nat. Hist., Vol.
100, art. 1, p. 54, 1952.]

Range. — Cardium s. s., Miocene to Recent.
Cosmopolitan. Recent from the intertidal zone to 200
meters (109 fathoms), occasionally deeper. Subfamily
Cardiinae, Late Triassic to Recent (Keen).

Description. — Shell ventricose, close or gaping
posteriorly; umbones prominent, subcentral; radiately
ribbed; margins crenulated; pallial line more or less
sinuated.

Animal with the mantle-margins plaited; siphons
clothed with tentacular filaments, anal orifice with a
tubular valve; branchial fringed; foot long, cylindrical,
sickle-shaped, heeled. (Tryon, G. W., Jr., Structural and
Systematic Conchology, Vol. 3, p. 192, 1884.)

Remarks. — This genus, construed in a broad sense,
is represented by about 200 species in all oceans. Some
species are quite tolerant of brackish water, where the
shell becomes smaller and thinner (823). Most of the
species occur in shallow to moderate depths, but some of
them occur down to depths of 183 meters (100 fathoms)
or more.

When submerged, the species of Cardium lie covered
with sand or sandy mud with only the edges of their shells
or only their siphons reaching the water. However, they
can move about by means of a strong muscular foot and
have been reported to be able to leap several meters at a
bound.

Sculpture of the shells is predominately radial al-
though the valves of certain groups are nearly smooth or
may have partial concentric ornamentation.

About a dozen anda half species have been described
occurring in Tertiary strata in western North America
and over a dozen are recorded living in marine waters be-
tween the Bering Sea and San Diego, California. About
two dozen species and subspecies have been reported as
living in tropical and subtropical west American waters.

Only three species, one referable to Cardium (Dallo-
cardia), one to Clinocardium, and one to Nemocardium,
are known with certainty to occur in the San Diego
Formation.

SUBGENUS DALLOCARDIA STEWART

Dallocardia Stewart, Acad. Nat. Sci. Philadelphia, Spec.
Publ. No. 3, pp. 37, 264, August 9, 1930.
Type species (by original designation). — “type
species, Cardium quadrigenerium Conrad’ [= Cardium
quadragenarium Conrad, Jour. Acad. Nat. Sci. Philadel-

259

phia, Vol. 7, Pt. 2, p. 230, pl. 17, fig. 5, 1837. “‘Inhabits
near Sta. Barbara; rare.’’ |
Range. — Late Oligocene (San Ramon Formation)

to Recent. Recent from the intertidal zone to 137
meters (75 fathoms).
Description. — Differs from Trachycardium in the

broader (longer) outline and in that the elongated nodes
on the central ribs are placed diagonally on the posterior
(and on some specimens also, to a lesser degree, on the
anterior) sides.

Remarks. — Trachycardium Morch (824) differs
from Dallocardia in that the shell is narrower in compari-
son to the height, the hinge is relatively coarser and
especially in that the scales on the central ribs loop over
the entire top of the ribs.

Stewart mentioned that Dallocardia and Trachy-
cardium are not known to occur earlier than Neogene time.
More recently Eames (825) questioned whether or not
certain species in the Eocene strata of Pakistan might be
referable to Trachycardium. Gardner (826) gave the range
as Cretaceous to Recent, and Stephenson (827) referred
a species from the Cenomanian, Cretaceous, of Texas, to
Morch’s unit. Finlay and Marwick (828) indicated that in
New Zealand, Trachycardium is restricted to the Waito-
taran Stage, early Pliocene.

Cardium (Dallocardia) quadragenarium Conrad
Plate 46, Figures 18, 20, 23

C[ardium]. quadragenarium Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 230, pl. 17, fig. 5,
1837.— Weymouth, State Calif. Fish Game Comm., Fish
Bull. No. 4, p. 28, pl. 5, fig. 1, 1924. “off shore from
Santa Barbara southward.”

Laevicardium (Trachycardium) quadragenarium Conrad,
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1,
p. 306, pl. 19, fig. 15, 1931. Various localities, early
Miocene to Recent.

Trachycardium quadragenarium Conrad, Fitch, State
Calif. Dept. Fish Game, Mar. Fish. Branch, Fish
Bull. No. 90, p. 55, fig. 21, 1953. “Monterey Bay,
California, to Cape San Lucas, Baja California,”
Recent. — Abbott, American Seashells (D. Van Nos-
trand Co., Inc.), p. 398, pl. 31, fig. A, 1954. ‘Santa
Barbara to Lower California.”

Type specimen. — Location unknown to the present
authors.

Type locality. — “Inhabits near Sta. Barbara; rare.”

Range. — Late Miocene to Recent. Recent from
Monterey Bay, California (A. G. Smith and Gordon,
1948), to Todos Santos Bay, Lower California, from the
intertidal zone to 137 meters (75 fathoms). In sandy mud
with the edges of the valves projecting above the surface,
in sloughs and sheltered waters of the open coast.

Occurrence in San Diego Fm. — C.A.S. 1402.
L.A.M. 305, 305A.

Original description. — Shell cordate, subequilateral,
ventricose, thick; ribs forty to forty-two, prominent, sub-
angular, flattened at the sides with a series of small
tubercles, which, on the anterior side, are largest, and
placed in the middle of the ribs, but elsewhere on the
posterior angular margin of the ribs; umbo_ broad,

260

prominent; beaks not oblique; tubercles elevated on the
posterior slope; colour pale yellow, with fulvous spots and

zones; posterior margin direct, deeply serrate. Height,
three inches. (Conrad.)
Remarks. — Two specimens of this species are

present in the Academy’s collection from Balboa Park. A
left valve, the better preserved of the two, is 51 mm high
and 49.8 mm long. Although the preservation is im-
perfect, the shape, number of ribs (41 visible) and the
spiny sculpture all correspond well with Recent specimens
of Cardium quadragenarium of the same size. The umbonal
portion of two valves, the large one about 50 mm high,
and some other fragments, were collected at Loc. 305
(LAM) near the Mexican boundary. These valves also are
similar to Recent specimens. A large Recent specimen
from San Pedro, California, in the Hemphill collection in
the California Academy of Sciences, is 124 mm long and
112 mm wide.

A fossil from Pliocene beds in Elsmere Canyon was
described by Arnold as “‘Cardium quadrigenarium Conrad
var. fernandoensis.”’ (829). It was said to differ from the
typical species as follows: ‘‘This variety is more oblique,
has narrower umbones, is relatively less in diameter, and
has fewer and less prominently spinose ribs than the
typical form.” We have examined a cast of Arnold’s type
specimen. It possesses 36 ribs and agrees with Arnold’s
description of this form.

The species described as Trachycardium sagaseri
(830) by Adegoke, from the Etchegoin Formation, is
said to possess about 28 radial ribs.

The early Miocene species described as Cardium
(Trachycardium) vaquerosensis Arnold (831) was said to
differ from the form fernandoensis as follows: ‘“‘It differs
from C. quadrigenarium Conrad, var. fernandoensis
Arnold, from the lower Pliocene, by being much larger,
more convex, having more prominent umbones, and
having fewer, wider, deeper, steeper-sided interspaces.”
The type specimen has 34 radial ribs. As mentioned by
Arnold, C. vaquerosensis is almost certainly the pre-
cursor of C. quadragenarium.

The species described as Cardium (Trachycardium)
gorokuense Nomura (832) was compared by its author
with C. quadragenarium. The Japanese fossil is a very
small shell 3.7 mm in length and in general features
resembles small specimens of Conrad’s species. However,
the ornamentation of the ribs appears to be different as it
is said to bear closely set concentrically arranged scales,
those on the posterior area somewhat spinose.

[Cardium (Mexicardia) procerum Sowerby]

Cardium procerum Sowerby, Proc. Zool. Soc., London
for 1833, p. 83, September 8, 1833. — Reeve, Conch.
Icon., Vol. 2, Cardium, sp. 51, pl. 10. fig. 51, 1844.
Original locality cited. — Dall, Proc. U. S. Nat. Mus.,
Vol. 1, p. 11, 1878. Later Tertiary of San Diego. Also
Recent. — Cooper, Calif. State Min. Bur., Seventh Ann.
Rept. State Mineral., p. 232, 1888. “Pl. — San Diego
well.”” — Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 5, p. 1091, 1900. “From the Pliocene of the well
in the City Park at San Diego, California.”

Type specimen. — Syntypes in British Museum

(Natural History).

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Type locality. — “Hab. in America Centrali. (Real

Llejos).”’ ‘‘Found in coarse sand in from four to six
fathoms water.”
Range. — Pliocene to Recent, Costa Rica, and

Ecuador; late Pleistocene to Recent in Lower California;
late Pleistocene in southern California. Recent from
Lagoon Head, Lower California. (Lat. 28° 15' N., Long.
114° 07' W.), and the Gulf of California, to Bahia de la
Independencia (Lat. 14° 15'S.), Peru (Olsson).

Occurrence in the San Diego Formation. — San
Diego well (Cooper; Dall).

Remarks. — This species was not cited by Dall in his
original list (1874) of the species found in the San Diego
well. The first record of Cardium procerum in beds which
might be presumed to be of Pliocene age at San Diego is
that of Dall in 1878 in which he referred to its occurrence
in “‘later Tertiary deposits.” Cooper, 1888, cited it as oc-
curring in the Pliocene strata of the San Diego well as did
Dall in 1900. We do not know what specimens formed
the basis of these records nor have we seen any specimens
from beds of Pliocene age in that region.

Most authors consider the range of Cardium proce-
rum to be from the southern portion of the outer coast of
Lower California, and the Gulf of California, to Peru.
Keen (1958, p. 116) recognized a northern form, said to
be characterized by its triangular ribs (often with fine
nodes along the crest) separated by linear interspaces,
under the name of Trachycardium (Mexicardia) panamense
Sowerby. The generally more southern form said to be
characterized by its smooth, rounded ribs separated by
rather wide, flat interspaces, was referred to Trachycardium
(Mexicardia) procerum Sowerby. However, many authors
consider these forms to be referable to a single species (see
Olsson, 1961, p. 247).

GENUS CLINOCARDIUM KEEN

Clinocardium Keen, Trans. San Diego Soc. Nat. Hist., Vol.
8, No. 17, p. 119, March 12, 1936. — Habe, Gen. Jap.
Shells, Pelecypoda No. 2, p. 150, 1951. ‘“‘Type species:
Cardium nuttalii Conrad, 1837.”

Type species (by original designation). —“Genotype:
Cardium nuttallii Conrad, 1837.”

Range. — Late Oligocene or early Miocene (Japan),
middle Miocene (western North America), to Recent.
Recent from southern California to Japan, one species
ranging through Arctic waters to the north Atlantic.
Recent from the intertidal zone to 119 meters (65
fathoms). Occasionally reported deeper.

Original description. — Shell medium to large,
trigonal, oblique, usually ventricose; beaks recurved, proso-
gyrate; position of the umbones varying with age but
usually at two-thirds the distance between posterior and
anterior ends of the shell; dorsal margin very broadly
arched, sloping downward at an angle of about 25°, ventral
and anterior margins broadly rounded; epidermis closely
adherent, brownish; sculpture of 28 to 55 rounded radial
ribs and concentric growth lines which may cross the ribs
as conspicuous loops, never as spines; lunule when present
circumscribed, never impressed; escutcheon inconspicuous;
ligament in dorsal view long, narrow, and oval. Interior
porcellaneous, ventral and anterior margins crenulate;

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

hinge arched; cardinals in each valve slightly nearer
anterior margins crenulate; hinge arched; cardinals in each
valve slightly nearer anterior than posterior laterals;
anterior, also recurved; ligament not elevated on a short,
shelly platform; beaks originating at a point slightly an-
terior to the anterior cardinals; muscle scars large; pallial
line simple. Specimens range in length up to about
120 mm. (Keen.)

Remarks. — This genus includes thirteen species and
subspecies from the late Cenozoic of western North
America and about fifteen species from Japan and
Sakhalin Island. One species is here recorded from the
San Diego Formation for the first time. This is essentially
a northern group of cockles. The type species has been
recorded from beds of Pleistocene age as far south as San
Quintin, Lower California, Mexico. Beal (833) mentioned
“Cardium aff. C. meekianum Gabb” from much farther
south, from beds of late Miocene age near Bahia de
Magdalena.

Clinocardium differs from Cerastoderma Poli in
Morch (834), from the eastern Atlantic, in the strongly
prosogyrate beaks, more numerous ribs, long, low ligament
and arched hinge line. The prosogyrate beaks, coarse
ribbing as well as the longer and lower ligament are
features separating Clinocardium from Laevicardium
Swainson (835).

The west American species of Clinocardium were
discussed by Keen (836) and those of Japan by Hirayama
(837).

Clinocardium nuttallii Conrad
Plate 46, Figure 21

Cochlea corbis Martyn (of west American authors), Univ.
Conch., Vol. 2, fig. 80, 1788 [ Martyn’s work was ruled
unacceptable for nomenclature by the Internatl.
Comm. Zool. Nomencl.,Opinion 456, March 15, 1957.]
— Chenu, Bibl. Conchyl., Premiere Sér., Vol. 2, p. 25,
pl. 28, fig. 2, 1845. ‘“‘Pulo-Condore.”

Cfardium]. nuttalli Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 229, pl. 17, fig. 3, 1837.

Cardium corbis Martyn, Weymouth, Calif. State Fish
Game Comm., Fish Bull. No. 4, p. 28, pl. 5, fig. 2,
1920. Gulf of Georgia, British Columbia, to San Diego,
California, Recent. — I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 142, pl. 34, figs.
la, 1b, 1924 (under subgenus Cerastoderma). Various
localities cited.

Laevicardium (Cerastoderma) corbis Martyn, Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 307,
pl. 19, figs. 14, 17, 1931. Various localities; late
Miocene to Recent.

Clinocardium nuttalii Conrad, Fitch, State Calif. Dept.
Fish Game, Mar. Fish Branch, Fish Bull. No. 90, p. 57
fig. 23, 1953. Bering Sea to San Diego, California.
Recent. — Addicott, U. S. G. S., Prof. Paper 523-C,
p. C-4, pl. 3, fig. 1, 1966. Half a mile east-northeast of
Ano Nuevo, San Mateo Co., California. Pleistocene.

Type specimen. — One pair, No. 54036, Academy of

Natural Sciences of Philadelphia (A. M. Keen, Veliger, Vol.

8, No. 3, p. 169, 1966).

Type locality. — “‘Inhabits muddy salt marshes, a few

261

miles from the estuary of the Columbia River.”

Range. — “‘aff.’’ Middle Miocene (838); late Miocene
(C. E. Weaver); Pliocene to Recent. Recent from Kamts-
chatka to San Diego, California, from low tide to 55
meters (30 fathoms). Reported from Miocene to Recent
in Japan.

Occurrence in San Diego Fm. — L.A.M. 107, 305,
A-1323.

Original description. — Shell ovate-triangular, ventri-
cose, thick; ribs thirty-four, regularly rounded, with
prominent arched striae; umbo narrowed; summit very
prominent; posterior slope much depressed; posterior
margin straight, oblique, simply undulate; ligament margin
declining; basal margin regularly arcuate; colour white;
epidermis yellowish brown; lateral teeth thick and prom-
inent; margin profoundly serrate. Height, three and a half
inches. (Conrad.)

Remarks. — One specimen from Loc. 107 (LAM)
partly decorticated, is 70.5 mm long and 84 mm high
(beaks lacking) and has about 34 to 35 radial ribs. The
shape and shell characters are those of Clinocardium
nuttallii Conrad. This identification was confirmed by
Dr. A. M. Keen who has made a special study of the
Cardiidae. Two other casts and one incomplete specimen
with portions of the shell, referable to this species, were
collected at the same locality.

Two casts of valves in the collection of the Los
Angeles County Museum were collected in Fossil Canyon
near Chula Vista, the large one is approximately 80 mm
long and 86 mm high. The shape and such traces of shell
as remain agree with C. nuttallii. A right valve from Loc.
305 (LAM), about 43 mm long, the ribs nearly eroded,
appears to be referable to this species.

Fraser (839) discussed the ecology of C. nuttallii.
He found that most of the specimens were about four
years old but that it may attain an age of seven years.
He also pointed out that in the early stages of growth the
length is greater than the height but after the first winter
the height exceeds the length and this difference increases
with age. This ratio of length to height may vary because
a huge specimen from Atka Island, Alaska, mentioned by
Keen (840) was 145 mm long, 138 mm high and the
convexity 102 mm.

Mitchell (841) made a study of the microscopic
structure of the shell and ligament and Taylor (842) dis-
cussed the effect of temperature on the growth of this
species.

Clinocardium nuttallii differs from the well known
Pliocene species, C. meekianum Gabb (843), in the less
oblique outline, less abrupt posterior truncation and in the
more numerous, narrower radial ribs (about 34 rather than
about 28) which continue on over the posterior truncation.

Asubspecies, Clinocardium meekianum myrae (844),
from the Etchegoin Formation, with 28 to 30 ribs, was
described recently by Adegoke.

This is the first record of Clinocardium nuttallii in
the San Diego Formation, but it has been recorded from
beds of similar age along the Pacific coast from Cali-
fornia to Alaska. It has been reported from beds of
Pleistocene age as far south as San Quintin, Lower Cali-
fornia.

Slodkewitsch (845) reported this species from beds
of late Tertiary age in Kamchatka and on Sakhalin Island
and it also has been reported ranging from Miocene to

262

Recent in Japan (846).

Clinocardium nomurai Hayasaka (847) bears a
general resemblance to C. nuttallii but it has only about
20 radial ribs and a smaller apical angle.

Clinocardium shinjiense Yokoyama (848) described
from strata of late Tertiary age in Japan, with about the
same number of ribs, has been confused with C. nuttallii
but the sharp angular ribs are quite different and more
closely resemble those of C. ciliatum Fabricius.

Fraser mentioned that C. nuttallii prefers a some-
what uniform sandy bottom or, if gravelly, confined to
patches where the gravel is fairly uniform in size.

GENUS NEMOCARDIUM MEEK

Nemocardium Meek, Rept. U. S. Geol. Surv. Terr., Vol.

9, p. 167, 1876. Cardium semiasperum Deshayes
cited. — Stewart, Acad. Nat. Sci. Philadelphia, Spec.
Publ. No. 3, p. 273, 1931. Type (monotypy): Car-
dium semi-asperum Deshayes. — Tremlett, Proc. Mala-
col. Soc. London, Vol. 28, Pts. 4 & 5, p. 115, 1950
“Type-species. — Cardium semiasperum Deshayes.”
— Keen, Bull. Amer. Paleo., Vol. 35, No. 153, p. 9,
1954. Type as designated by Sacco.

Type species (by monotypy.) Also designated by
Sacco, Moll. Terr. Terz. Piemonte e Liguria, Pt. 27, p. 56,
1899). — “tipo N. semiasperum (Desh.)” [Cardium semi-
asperum Deshayes, Anim. s. Vert. Bassin Paris, Vol. 1,
De Wilosmplebos igssale, 2.01860! “Localities: Aizy,
Vregny, Laon.” “Gisement: Sables inférieurs.” France,
Eocene. — Tremlett, Proc. Malacol. Soc. London, Vol. 28,
Pts. 4 & 5, p. 121, pl. 16, figs. 9a, 9b, 1950. Hampshire
Basin. London Clay, Eocene. |

Range. — Late Cretaceous to Recent. Recent from
18 to 200 meters (10 to 109 fathoms). d

Original description. — Shell closely resembling the
typical forms of Protocardia, but thinner, with two-thirds
to three-fourths of surface in front of the stronger post-
erior, usually echinate, radiating costae, occupied by fine,
crowded, radiating striae, and the free margins crenate
within all around; cardinal and lateral teeth generally
rather slender; pallial line faintly sinuous, irregularly
serrated, or nearly simple behind. (Meek, 1876.)

The cardinal teeth in the hinge of this genus are
very unequal in size.

Remarks. — Nemocardium is represented by a num-
ber of species throughout its geologic range, the greatest
number of which occur in strata of Eocene age as indicated
by Keen (849) in a discussion of this genus. In Europe
Nemocardium s. s. is reported to range from Cretaceous
to Miocene. In England it ranges from Cretaceous to
Oligocene (Headon beds (see Tremlett)). According to
Finlay and Marwick (850), large forms of Nemocardium
appeared in New Zealand first in the Kaiatan Stage, early
Oligocene, and made their last appearance in the Awamoan
Stage, middle Miocene. Later, Keen (1950, p. 25) re-
ported the occurrence of one species of this genus in the
Eocene of Australasia. In western North America
Nemocardium s. s. ranges from late Cretaceous to middle
Oligocene. The last representative in this region, so far as
known, is Cardium weaveri Anderson and Martin (851)
described from the Oligocene of Oregon. Recently,

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Hickman (852) described Nemocardium (Nemocardium)
formosum from strata in western Oregon assigned Oligocene
age. Five Cenozoic species from the North American-
northeast Asia region were referred by Keen [1954, p.
316 (10)] to Nemocardium s. s. In Japan this genus
ranges from late Cretaceous to Recent, being represented
in Oriental waters at the present time by Cardium bechei
A. Adams and Reeve (853).

Stewart (854) gave a discussion of the genus Proto-
cardia Beyrich, the type of which is Cardium hillanum
Sowerby, and he pointed out the differences between that
genus and Nemocardium. The posterior portion of the
valves of the genus Protocardia is sculptured with radial
ribs and the remainder of the valves is sculptured with
concentric ribs.

Four rather similar subgenera of Nemocardium are
separated in the following key which is adapted from
Keen, 1954.

Key to Subgenera of Nemocardium

A. Posterior ribs decidedly wider
and heavier than the others,
usually with spines
or crests . Nemocardium s. s.

B. Posterior ribs not decidedly
wider than the others.

a. Outline ovate-trigonal;

hinge relatively short . . Arctopratulum
aa. Outline ovate-trigonal; hinge
relatively long and arched
b. Concentric lamellae on
posterior area only . . Keenaea

bb. Concentric lamellae present

over entire valve Pratulum

SUBGENUS KEENAEA HABE

Keenaea Habe, Gen. Jap. Shells. Pelecypoda, No. 2, p.
152, September, 1951. — Keen, Bull. Amer. Paleo.,
Vol. 35, No. 153, p. 317 (11), 1954. Original designa-
tion of type cited.

Type species (by original designation). — ‘“Type
species: Cardium samarangae Makiyama.” [= Nemocar-
dium samarangae Makiyama, Mem. Coll. Sci., Kyoto Imper.
Univ., Ser. B, Vol. 10, No. 2, art. 6, p. 143, 1934. A new
name for Cardium modestum A. Adams and Reeve, Zool.
Voy. Samarang, Moll., Pt. 3, p. 77, pl. 22, fig. 6, 1848
(issued 1850). ‘Hab. Eastern Seas.” (Not Cardium
modestum Philippi, 1849; not Cardium modestum Conrad,
1855). Also illustrated by Habe, 1951, fig. 326 (p. 147).]

Range. — Late Oligocene to Recent. Japan to Lower

California. Recent from 18 to 476 meters (10 to 260
fathoms).
Description. — Smaller than Nemocardium s. s.,

with secondary concentric lamellae on posterior ribs; the
latter not sharply differentiated. Differs from N.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

(Pratulum) by the presence of the concentric lamellae on
ribs and a tendency toward fine beading on ribs of the
central part of the disk. (Keen, 1954.)

Remarks. — Several Cenozoic species of the Cardiidae
in the north Pacific region have at times been placed in
various genera or subgenera such as Protocardia Beyrich,
Nemocardium Meek, and Pratulum Iredale. Establish-
ment of Keenaea as a subgenus for these species appears
justified because of differences in the sculpture and hinges
of these forms in comparison with the type species of
other supraspecific units of the Cardiidae. Five Cenozoic
species in the north and northeastern Pacific regions have
been assigned (one tentatively) by Keen to the present
subgenus.

Nemocardium (Keenaea) centifilosum Carpenter
Plate 46, Figures 4, 5, 10, 15

Cardium (?modestum, var.) centifilosum Carpenter, Rept.
Brit. Assoc. Adv. Sci. for 1863, p. 611, issued August,
1864. Reprint in Smithsonian Misc. Coll., No. 252,
p. 97, 1872. — Carpenter, Proc. Calif. Acad. Nat. Sci.,
Vol. 3, p. 209, February, 1866. ‘Monterey, 20
fms. alive; Santa Barbara I, Catalina Island, 40 fms.
Cooper.”

Cardium var. centifilosum Carpenter, Rept. Brit. Assoc.
Adv. Sci. for 1863, p. 642, issued August, 1864. Re-
print in Smithsonian Mise. Coll., No. 252, p. 128, 1872.

Cardium centifilosum Carpenter, Dall, Proc. Calif. Acad.
Sci., Vol. 5, p. 297, 1874. “Well at San Diego.” “‘Plio-
cene.”” — Dall, Proc. U. S. Nat. Mus., Vol. 1, p. 28,
1878. San Diego well. — Cooper, Calif. State Min.
Bur., Seventh Ann. Rept. Calif. State Mineral. p. 232,
1888. ‘Pl. — San Diego well.” — Orcutt, West Amer.
Sci., Vol. 6, Whole No. 46, p. 85, August, 1889.
Dall’s record (1874) cited. — Orcutt, cited by Ellis in
Ellis and Lee, U. S. G. S., Water Supply Paper 446,
p. 59, 1919. Dall’s record (1874) cited from San Diego
well. — Hertlein and Grant, Mem. San Diego Soc. Nat.
Hist., Vol. 2, Pt. 1, p. 48, 1944. Dall’s record
(1874) cited. Referred to Nemocardium centifilosum
Carpenter.

Protocardia centifilosa Carpenter, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 142, 1903. ‘San Diego well
(Dall).” “‘Pliocene.”” — I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 146, pl. 34, figs.
2a, 2b, 2c, 2d, 1924. Recent. Also cited from ‘‘San
Diego.” ‘‘Pliocene.’’ — Hertlein, Stanford Univ. Bull.,
Ser. 5, No. 78, p. 84, 1929. ‘“‘San Diego Pliocene.”

Cardium (Protocardia) centifilosum Carpenter, Packard,
Univ. Calif. Publ. Zool., Vol. 14, No. 2, p. 267, pl. 20,
figs. 2a, 2b, 2c, 2d, 1918. ‘Vicinity of the Farallon
Islands in 40 to 46 fathoms.”

Nemocardium (Keenaea) centifilosum Carpenter, K. V. W.
Palmer, Geol. Soc. America, Mem. 76, pl. 91, pl. 10
figs. 7-11, 1958. (Holotype illustrated.)

Type specimen. — No. 15262, United States Na-
tional Museum.

Type locality. — ‘Cat. Is., 30 — 40 fm.’ Carpenter,
(1864, p. 611.) [Catalina Island, California. See K. V. W.
Palmer, 1958, p. 92. ]

Range. — Late Miocene (856) to Recent.

>

Recent

263

from the Farallon Islands, California, to Point Abreojos,
Lower California, Mexico, in 18 to 137 meters (10 to 75
fathoms).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 1404, 12078, 28893. L.A.M. 107, 305A.
S.D. 75, 294.

Original description. — ‘‘Probably = modestum, Ad.
& Rve.; but rounder, ribs sharper and more distant.”

Supplementary description. — C. T. parva, tenuis-
sima, inflata, subquadratim rotundata; umbonis angustis,
tumidioribus; marginibus, dorsalibus subalatis, antico et
ventrali aequaliter rotundatis, postico vix truncato, tota
superficie, (nisi umbonibus et dorsum versus utroque
latere laevigus,) tenue lirata; liris cire. centum, quoad
magnitudinem extantibus, angustis; interstitiis sub-equal-
ibus, subquadratis, interdum punctato-decussatis; parte
postica a linea definita, lirulis minus conspicuis, laminis
concentricis extantibus, crebrioribus eleganter exasperata;
intus, dent. card. validioribus, lat. subdistantibus; cic.
adduct. ovalibus, haud impressis.

Long. 0.51, lat. 0.48, alt. 0.34. (Carpenter, 1866.)

Remarks. — The radial ribs on the posterior third of
the shell of this species separated from the anterior series
by a slight carina, are crossed by raised concentric
lamellae.

A considerable number of specimens of Nemocar-
dium centifilosum in various stages of preservation, are
present in the collections from the San Diego Formation.
These vary in size, many of those from Loc. 1404(CAS),
corner of India and Upas streets, are about 16 mm high;
one of the largest ones is 18.8 mm high. A single left
valve in the Hemphill collection from the San Diego well
is approximately 16.4 mm long and 16.1 mm high.
The largest specimen from Loc. 107 (LAM), end of
Arroyo Drive, is a cast 19.8 mm long and 19 mm high.
An impression of a right valve collected by Charles
Sternberg on Reynard Way off State Street, is 22 mm long.
One of the largest Recent specimens of N. centifilosum in
the collections of the California Academy of Sciences
from Cortez Bank off southern California, in 73 to 110
meters (40 to 60 fathoms), is 16.8 mm long and 16 mm
high, convexity (both valves together), 11 mm. The
fossil specimens agree in all observable characters with
those of the Recent species.

A cast of both valves of a specimen from Loc. 107
(LAM), has the general shape of Nemocardium but it is
much larger than any specimens of N. centifilosum which
we have observed. It is 33.8 mm long, 33 mm high, the
convexity (both valves together), approximately 27.3 mm.
The shell material is lacking and no opinion is here ven-
tured concerning the species represented by this cast.

A form described as Cardium richardsoni by
Whiteaves (857) is now generally considered to be only a
northern variety of Nemocardium centifilosum, ranging
from Forrester Island, Alaska, to San Francisco, California.
Dall (858) stated concerning this form, ‘‘The northern
specimens forming the variety are a little stronger and
coarser than those from California, with which they seem
to be united by intermediate gradations, though the ex-
tremes have apparently good distinctions.’”’ However, as
mentioned by Willett (859), and by Woodring, Bramlette,
and Kew (860), the only difference between the northern
and southern forms is in size. We have examined speci-
mens collected by George Willett at Forrester Island,

264

Alaska, the largest of which is 21.6 mm long, 19.6 mm
high, convexity (both valves together), 15.1 mm. Wood-
ring, Bramlette, and Kew, reported large shells from
Alaska which are 26.2 mm long and mentioned that the
largest one from off Cortez Bank in the United States
National Museum, is 19.6 mm long. A fossil valve which
they illustrated from beds of Pleistocene age from San
Pedro, California, is 24.9 mm long and 22.8 mm high
and thus comparable in size to the northern form N.
centifilosum richardsoni.

SUPERFAMILY VENERACEA RAFINESQUE (861)
FAMILY VENERIDAE RAFINESQUE (862)

Shell equivalve, porcelaneous, beaks prosogyrous,
smooth or variously sculptured (predominantly concen-
tric), lunule and escutcheon usually well defined, resilium
external, margins crenulated or smooth; pallial sinus
varying in different genera, often deeply sinuated; hinge
with teeth radially arranged, one or more of the cardinals
often bifid or grooved, right middle and left posterior ones
usually thicker than right and left anterior teeth, a left
anterior lateral may be well developed or lacking, poster-
ior laterals usually small or lacking. Often burrowing just
beneath surface of sea bottom. Jurassic to Recent.

Remarks. — This family, which has reached its
greatest development and diversification at the present

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

time, contains many genera for which scores of names (see
Frizzell, 1930) have been proposed.

Several authors have given special attention to this
family among which are Dall (863), Jukes-Browne (864),
Marwick (865), Palmer (866), Frizzell (867), Casey (868),
and Keen (869). References to earlier works on this
family can be found in those papers. A study of the
Veneracean group led Casey to conclude (p. 158), “the
author is convinced that the genera at present grouped
in the family Veneridae (the superfamily Veneracea of
Frizzell, 1936) are a polyphyletic assemblage of forms
derived from various cyprinid and noncyprinid sources.”
However, he believed it best to leave undisturbed the
systematic homogeneity of this well known family until
evidence of a phylogenetic classification had been pre-
sented.

Recent tropical and subtropical west American
species of the Veneridae were discussed by Hertlein and
Strong (870), by Keen (871), and by Olsson (872).

Ansell (873) discussed the functional morphology
of the British species of Veneracea.

GENUS DOSINIA SCOPOLI

Dosinia Scopoli, Introductio ad historiam naturalem, p.
399, 1777. Reference to: ‘“‘Cricompholos Klein.
Chama Dosin. Adans.” — Hertlein and Strong, Bull.

Key To Genera Of Veneridae (874)

A. Left valve with an anterior
lateral tooth or denticle.

a. Shell orbicular, large,

polished: bss Ss Bierg > Dosinia
aa. Shell trigonal or elongated.
b. Shell trigonal, beaks
subcentral . . . . . Tivela

bb. Shell longer than high;
beaks anterior to midline.

c. Inner ventral margin obliquely
grooved; not exceeding
35 mm in length .
cc. Inner ventral margin not
grooved

Transennella

d. Exterior of valves with coarse
concentric sculpture
dd. Exterior of valves smooth
or with fine concentric
sculpture

Saxidomus

e. Pedal retractor impression
deeply excavated; shell
larger rather
thickimectecoy eae ios

ee. Pedal retractor impression
not deeply excavated;
shell rather thin .

. Megapitaria

Pitar

B. Left valve lacking an anterior
lateral tooth or denticle

a. Exterior of valves smooth
or with fine concentric
sculpture

b. Shell obliquely elliptical,
medium-sized to large;
pallial sinus narrow

bb. Shell trigonal, not
exceeding 8 mm in length;
pallial sinus wide .

Compsomyax

- Psephidia

aa. Exterior of valves with concen-
tric and radial (always on
beaks) sculpture
c. Escutcheon present on one
or both valves

d. Left posterior cardinal
elongated; middle cardinal
thick; hinge plate triangular;
pallial sinus short :

dd. Left posterior cardinal
short; middle cardinal not
thickened, bifid; hinge
plate narrow and long;
pallial sinus long -

Chione

Protothaca

ee. Escutcheon lacking Trusella

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Amer. Mus. Nat. Hist., Vol. 107, Art. 2, p. 188, 1956.
Type (by monotypy): Chama Dosin Adanson.

Dosinidia Dall., Proc. U. S. Nat. Mus., Vol. 26, No. 1312,
p. 437, December 29, 1902. “Type, Venus concentrica
Born.” [Rer. Nat. Mus. Caesarei Vindobonensis, Pars 1,
Testacea, p. 58, 1778. (No locality cited. Ref. to “List
Hist. Conch. 1, 3, f. 99, 102, 104.”’; “‘Petiv. Gaz. t. 16,
f. 1, t. 93, f. 15, 18.”); Test. Mus. Caesar. Vindobonen-
sis, p. 71, pl. 5, 1780. ‘Habitat ad insulam Maurittii&
Jamaicam, Lister.’’]

Type of genus (by monotypy): Chama Dosin Adan-
son, Hist. Nat. du Sénegal, p. 225, pl. 16, fig. 5, 1757. “On
la voit assez abondamment sur la cote de Portudal.” See
Fischer-Piette et al., Jour. de Conchyl., Vol. 85, No. 4,
p. 308, pl. 14, fig. 4, 1942 [A Dosinia (Dosinia) concen-
trica|. Also illustrated by Palmer, Palaeontogr. Ameri-
cana, Vol. 1, No. 5, p. 278, pl. 49, figs. 2, 5, 10; pl.-51,
fig. 4, 1927-1929. Pleistocene and Recent.

Range. — Eocene to Recent in New Zealand (Mar-
wick); Oligocene (876) to Recent in western North
America. Recent mostly in shallow tropical and subtropi-
cal waters to a depth of 120 meters (66 fathoms).

Description. — Shell orbicular, rather thick, valves
moderately inflated, posterior dorsal margin usually very
gently rounded and lending a flattened appearance; lunule
well defined, escutcheon, if present, narrow, lacking in
Dosinia s.s.; sculpture of fine, incised concentric grooves;
hinge of left valve with 3 cardinals, ligament rather long,
more or less sunken; pallial sinus usually ascending, pointed
at the end; margins of valves smooth.

Remarks. — A discussion concerning the identifica-
tion of the type species of this genus has been given
by Fischer-Piette et al. and reviewed by Hertlein and
Strong. It appears that Adanson’s species “Chama Dosin”
is identical with Venus concentrica Born. The subgenus
Dosinidia Dall is thus a synonym of Dosinia s. s.

The tropical and subtropical genus Dosinia is repre-
sented in Neogene strata of western North America by
several species. It ranged north to western Washington
during middle Miocene time, but only north to Santa
Clara Co. (877), California, in the Pliocene, and to Newport
Bay, California, in late Pleistocene time.

One species, or perhaps two, and a subspecies de-
scribed in the present paper, occur in strata of Pliocene age
in southern California but only one occurs in beds of
Pleistocene age in that region. Three species occur in the
tropical and subtropical waters between Scammon’s La-
goon, Lower California, to Punta Penasco, Mexico, and
south to Ecuador and two of them to Paita, Peru. Re-
cords of the occurrence of Dosinia ponderosa living in the
waters of San Diego Bay are believed to have been based
upon Pleistocene fossils.

SUBGENUS DOSINIA S. S.

Dosinia ponderosa diegoana n. subsp.
Plate 47, Figures 2, 3, 6, 8, 10; Plate 49,
Figure 8; Plate 51, Figure 14

Dosinia ponderosa (Gray) variety jacalitosana Arnold,
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.
1, pp. 353, 912, pl. 15, figs. 2a, 2b, 1931. ‘“Dosinia
beds of Balboa Park, San Diego (Hertlein and Grant).”

265

Not Dosinia jacalitosana Arnold, 1910.

Dosinia ponderosa (Gray), var., Woodring, in Woodring
and Bramlette, U. S. G. S., Prof. Paper 222, pp. 89,
104, pl. 16, fig. 6; pl. 19, fig. 1; pl. 20, fig. 7, 1950.
Careaga Sandstone, Santa Maria district. Also cited
from “U. S. Geol. Survey localities 2459, 2662
(Balboa Park)’’, San Diego.

Dosinia ponderosa Gray, Moore, San Diego Soc. Nat. Hist.,
Occas. Paper 15, p. 38, pl. 17, figs. a, b, 1968. “near the
Mexican-United States boundary and one-half a mile
from the ocean”. Pliocene.

Not Arthemis ponderosa Gray, 1838.

Description. — Shell large, elongately orbicular,
equivalve, moderately inflated, beaks situated decidedly
anterior; lunule large and impressed; anterior margin and
ventral margin broadly rounded, posterior dorsal margin
gently rounded and merging into the posterior margin
which is very broadly rounded and lending a subtruncated
appearance; surface sculptured with concentric incremental
lines; hinge similar to that of Dosinia ponderosa but the
ventral margin of the hinge plate is more arcuate and the
anterior lateral tooth of the left valve is separated by a
greater distance from the anterior cardinal. Length, 121
mm, height, 130 mm, convexity (both valves together,
gaping 13 mm along ventral margin), 63 mm.

Type specimen. — Holotype (and paratypes) in the
California Academy of Sciences, Department of Geology,
Type Collection; paratypes in the San Diego Society of
Natural History and in the Los Angeles County Musuem,
Invertebrate Paleontology Collection.

Type locality. — Dosinia beds in Balboa Park, on
point between Cabrillo Canyon and a gulch, about 100
meters south of the west end of Laurel Street Bridge over
Cabrillo Canyon, San Diego.

Range. — Middle Pliocene, San Diego Formation at
San Diego, and in the Careaga Formation in the Santa
Maria district, California.

Occurrence in San Diego Fm. — C.A.S. 1181, 1401,
1402, 1415, 36384. L.A.M. P.87, 104, 107, 127, 180,
305, 305A, 319. S.D. 29, 80, 408, 417, 05252. U.C.
A-8333. U.C.L.A. 312, 1386, 2359.

Remarks. — Dosinia ponderosa diegoana, new sub-
species, differs from Dosinia ponderosa in that the outline
is more elongated (dorsal to ventral), the beaks are more
anteriorly situated, the lunule is shallower, the posterior
dorsal margin is less projecting, lending a subtruncated
appearance to the posterior portion of the shell, the ventral
margin of the hinge plate is more arcuate, and the anterior
lateral of the left valve is separated from the anterior car-
dinal by a correspondingly greater space.

This subspecies appears to be intermediate in shell
characters between Dosinia ponderosa (878) and Dosinia
Jacalitosana Arnold (879). Some specimens from Balboa
Park are nearly as elongate in outline as D. jacalitosana but
on most specimens the posterior dorsal margin is more
acutely rounded than that of D. jacalitosana. The hinge
of the type of the latter has not been described, but Nom-
land (880) illustrated the hinge of a right valve attributed
to Arnold’s species. The results of a study of a series of
specimens from the San Diego Formation lead us to de-
scribe this form as a subspecies of D. ponderosa rather
than to identify it with D. jacalitosana or with either of
the forms of late Miocene age placed in the synonymy
of that species by Grant and Gale.

266

Woodring pointed out that the form which he
illustrated from the Careaga Sandstone in the Santa Maria
district is identical with the Dosinia occurring in Balboa
Park in San Diego.

The elongated form, very anteriorly placed beaks
and subtruncated posterior end are features easily separ-
ating this new subspecies from Dosinia arnoldi Clark and
D. merriami Clark from beds of late Miocene age in
California.

GENUS TIVELA LINK

Tivela Link, Beschreib. Naturalien-Sammlung Rostock,
Pt. 2, p. 152, 1807. Species cited: ‘‘Tivela vulgaris.”
“Venus corbicula. L. G. p. 3278” in synon.: and
“Tivela tripla.” “‘V. tripla. L. G. p. 3276” in synon. —
Nickles Moll. Test. Marins Cote Occid. d’Afrique, Man.
Ouest-Africain, Vol. 2, p. 199, 1950.

Type species (designated by Kobelt, Illustr. Con-
chylienbuch, Bd. 2, Lief, 10-11, p. 334, 1881). — “Typus
ist Cytherea tripla Linné (Taf. 97 Fig. 12) von der Westa-
frikanischen Ktiste.”’ [Also illustrated by Romer, Monogr.
Molluskengattung Venus, Linné (Cassel), Bd. 1, p. 20, pl.
7 figs. 2, 2a-c, 1861. West Africa. — Nicklés, 1950, p.
199, fig. 378. For a discussion of this species see Dodge,
H., Bull. Amer. Mus. Nat. Hist., Vol. 100, Art. 1, pp.
122-123, 1952.]

Range. — Eocene to Recent (Tivela s. s., Miocene to
Recent). Recent from the intertidal zone to 73 meters
(40 fathoms).

Description. — Shell trigonal, smooth, medium size;
external ligament short in the typical species; hinge with
three cardinal teeth in each valve and an anterior lateral
in the left valve; inner margins smooth; pallial sinus deep,
rounded at the end.

Remarks. — The type species is a highly trigonal
shell about 20-35 mm in altitude. The anterior and pos-
terior areas are flattened and a lunular area is delimited
by a fine thread. The external ligamental area is compara-
tively small. The pallial sinus extends anteriorly to about
two-thirds the distance from the posterior margin.

The general characters of the type species differ so
much from those of the huge coarse shells of west
American species usually referred to Tivela that it seems
desirable to place the California species in the subgenus
Pachydesma Conrad.

Dodge considered Herrmannsen’s designation of the
type of Tivela to be equivocal. There may be an element
of doubt concerning the validity of that designation but
there is no question concerning the validity of the desig-
nation of the same species by Kobelt.

SUBGENUS PACHYDESMA CONRAD

Trigonella Conrad, Jour. Acad. Nat. Sci. Philadelphia,
Vol. 7, Pt. 2, p. 253, 1837.
Sole species, Cytherea crassatelloides Conrad. Not
Trigonella Da Costa, 1778, nor Trigonella Hehl, 1842.
Pachydesma Conrad, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 7, p. 31, March 1854. New name for Trigonella
Conrad, 1837, not of Da Costa, 1778, nor of Hehl,

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

1842. “This name being superseded, I propose to sub-
stitute that of Pachydesma’’. — Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New
York), p. 266, 1961. Type species, Donax stultorum
Mawe.

Type species (by monotypy). — Cytherea crassatel-
loides Conrad.

Range. — Eocene to Recent. Recent from the inter-
tidal zone to about 24 meters (13 fathoms).

Description. — Shell large, thick, trigonally elongate,
porcelaneous, beaks prominent, lunule not defined; distinct
setting off of the left cardinal from the nymph; three cardi-
nal teeth in each valve (sometimes with accessories), a
large anterior lateral tooth in the left valve and two
lateral lamellae in the right valve.

Remarks. — The recorded occurrence of species of
Pachydesma in California in beds as early as those of
Eocene age suggests the possibility that this subgenus
originated in west American waters.

Tivela (Pachydesma) stultorum Mawe
Plate 50, Figures 4, 5, 6

Donax stultorum Mawe, Linn. Syst. Conch., pp. 37, 40,
pl. 9, fig. 7,1823. [No description. ]

C[ytherea]. crassatelloides Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 253, pl. 19, fig. 17, 1837
(under subgenus Trigonella).

Cytherea (Tivela) crassatelloides Conrad, Stearns, Proc.
U. S. Nat. Mus., Vol. 21, No. 1149, pp. 371-378, pls.
23-25, 1898. Santa Cruz, California, to Ballenas Bay,
Lower California.

Tivela stultorum Mawe, Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 340, pl. 19, fig. 8, 1931.
(Reproduction of Mawe’s original figure.) [Not figs.
3a, 3b? = Tivela scarificata Berry.] Pliocene to Recent.

Type specimen. — Location unknown to the present
authors. Type specimen of Cytherea crassatelloides
Conrad, one pair No. 53900, Academy of Natural Sciences
of Philadelphia (A. M. Keen, Veliger, Vol. 8, No. 3, p. 169,
1966).

Type locality. — “Indian Seas.” [Original locality
believed to be erroneous. The type locality of Cytherea
(Trigonella) crassatelloides Conrad, generally considered
to be identical with Donax stultorum Mawe, is, “‘Inhabits
the coast of California about a foot deep in the sand —
abundant round Sta. Diego as well as near Sta. Barbara.”’]

Range. — Middle Pliocene to Recent. Recent from
Stinson Beach, Marin Co., California (881), to Magdalena
Bay, Lower California, Mexico, from the intertidal zone
to a depth of 24 meters (80 feet), living at a depth of about
150 mm (6 inches), on a clean sandy beach where there
is a heavy surf.

Occurrence in San Diego Fm. — L.A.M. 305, 305C,
319, A-1323. U.C.L.A. 294, 305, 312, 1383.

Original description of Cytherea crassatelloides. —
Shell equilateral, triangular, thick; convex-depressed; lun-
ule undefined; posterior extremity truncated; ligament
short, very broad and elevated; apex very prominent; beaks
not oblique; colour whitish, frequently rayed with brown;
cardinal teeth very thick and prominent; anterior tooth
elongated, thick; sinus of palleal impression angular.
Length, seven inches. (Conrad.)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Remarks. — Several single valves of this species are
present in the collections of the University of California
at Los Angeles. The largest specimen, a right valve, is
78.8 mm long, 62.2 mm high, the convexity, 15.4 mm.
This is small in comparison to a Recent specimen collected
by Mr. John Strohbeen which is 162 mm long, 131 mm
high, the convexity (both valves together), 77.5 mm.
Fitch (882) mentioned a specimen which was 187 mm
long.

Two single valves and some fragments of this species
are present in the collections of the Los Angeles County
Museum. A fragment of a left valve from Loc. 305
(LAM), from near the Mexican boundary, is 10 mm thick.

The present record of this species in the San Diego
Formation is the first unless the equivocal record of Orcutt
(883) refers to specimens of Pliocene age. He cited it
from Tertiary beds at Pacific Beach. This species has
been recorded from other localities in California in
strata of Pliocene age in the San Benito quad., in the
Santa Maria district, in Los Angeles, and in the Merced
Formation in northern California.

There have been differences of opinion as to the
correct name for this species. Certainly Conrad’s Cytherea
crassatelloides from southern California is referable to this
species. However, most authors in modern times have
accepted Donax stultorum Mawe as representing this
species. The locality “Indian Seas” given by Mawe for
this species is generally believed to be an error. The only
modern record we have noticed of the identification of
Tivela stultorum in oriental waters is that in a list of shells
from Hongkong, mentioned by Campbell (884) who
attributed the identification to H. A. Pilsbry. That list
contains such American species as Pecten circularis Sower-
by, Olivella biplicata Sowerby, Busycon perversa Linnaeus,
and Olivella sayana Ravenel, and cannot be considered as
an authoritative locality record for Mawe’s species.

Woodring (885) considered the assignment of Donax
stultorum to west American waters a very doubtful pro-
cedure and preferred retention of the name Tivela crass-
atelloides for the west American species.

Cytherea virginea A. Adams and Reeve was described
with the locality ‘Eastern Seas.” Tomlin examined the
type specimen and concluded that it is identical with the
California species which he cited as Tivela stultorum. This
conclusion was affirmed by the French authors Fischer
and Fischer-Piette. Evidence supporting the opinions of
those authors is that several species recorded from oriental
waters by A. Adams and Reeve are now known to be
west American species. Among these are “Artemis”
dunkeri Philippi, “Mactra” thracioides A. Adams and
Reeve, ‘““Lucina” sericata Reeve, and Conus borneensis A.
Adams and Reeve (now believed to be identical with
Conus arcuatus Broderip).

The present authors feel that the use of Tivela stul-
torum for a west American species is justified unless
definite proof is forthcoming that the name is applicable
to an oriental species.

Tivela scarificata Berry (886) which occurs in beds
of Pleistocene age in southern California differs from
T. stultorum in the more elongate shape and in the pre-
sence of scar-like markings on the interior.

An interesting form generally considered to be
referable to Tivela stultorum has been discussed by Fitch
(887). He pointed out that individuals of this species

267

living in sand along with numerous specimens of Donax
gouldii develop an elongate shape and often reveal the
presence of an area of irregular zone of growth just an-
terior to the posterior umbonal margin. This irregular
growth is believed to be the result of injury to the corre-
sponding portion of the mantle caused by pinching by
the valves of Donax gouldii. One of the fossils in the
present collection shows a similar zone of irregular growth.

Two excellent papers dealing with Tivela stultorum
in present day waters are by Weymouth (888) and Fitch
(889). Young shells are said to possess a byssus which
later becomes obsolete.

[GENUS PITAR ROMER]

Pitar Romer, Kritische Untersuchung der Arten des
Molluskengeschlechts Venus bei Linne und Gmelin mit
Berticksichtigung der spater beschriebeben Arten (Cas-
sel), p. 15, 1857. Sole species, ““C. tumens Gmel.” —
Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ. No.
3, p. 232, 1930. Monotype species Venus tumens
Gmelin.

Caryatis Romer, Malakozool. Blatter, Bd. 9, pp. 58, 60,
March, 1862. Species cited: Cytherea tumens Gmelin,
Cytherea striata Sowerby, and others. — Stoliczka,
Mem. Geol. Surv. India, Palaeo. Indica, Ser. 6, Vol. 3
pp. XVIII, 151, 1871. ‘‘Venus tumens, Gmelin, is the
type of this very well marked form of Cytherea.”

Not Caryatis Hubner, 1816. Lepidoptera.

Pitaria Romer (emended), Dall, Proc. U. S. Nat. Mus.,
Vol. 26, No. 1312, p. 353, December 29, 1902. “‘Type
Venus tumens Gmelin.”

Type species (by monotypy): ‘“‘C. tumens Gmel.
(le Pitar Adans.)” [= Cytherea tumens Gmelin, Linn.
Syst. Nat., ed. 13, p. 3292, 1791. “Habitat ad Africa
littus occidentale.” Ref. to Adanson, Hist. Nat. du
Sénégal, pl. 16, fig. 7, 1857. Locality, p. 226, “Elle est
également répandue sur toute la cOte sablonneuse depuis
le cap Verd jusqu’au fleuve Gambie.’’ See also P. -H.
Fischer et al., Jour. de Conchyl., Vol. 85, No. 4, p. 316,
pl. 14, fig. 6, 1942. Also illustrated by Romer, Monogr.
Molluskengattung Venus, Linné, Bd. 1, p. 81, pl. 22,
figs. 1, la, 1b, 1c, 1869. “‘Mare Senegalense et Guineense;
(Bathhurst in ins. Stae Mariae).’’ Also illustrated by
Tegland, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol.
18, No. 10, p. 277, pl. 21, figs. 1-3, 1929 (as Pitaria
(Pitaria) tumens].

Range. — Eocene to Recent. Recent chiefly in
tropical and subtropical waters, a few species in warm
waters, from the intertidal zone to 540 meters (295
fathoms).

Description. — Shell medium-sized, trigonal-ovate,
strongly inflated; lunule wide, limited by a slightly de-
pressed groove; escutcheon indistinct; sculpture consisting
of incrementals; hinge of right valve consisting of 2 in-
distinct anterior lateral lamellae flanking a deep socket,
and 3 cardinals, the anterior (3a) and middle (1) ones
almost perpendicular to hinge-margin, the middle one
heavy, the posterior one (3b) bifid; hinge of left valve
consisting of a heavy anterior lateral and 3 cardinals, the
anterior one (2a) resembling the right anterior cardinal
(3a), the middle one (2b) very heavy and obscurely bifid,
the posterior one (4b) slender and partly joined to the
nymph; pallial sinus deep, its apex acutely angular.

268

(Woodring, W. P., Carnegie Inst. Washington, Publ. 366, p.
152, 1925.)

Remarks. — This genus is represented in the Cenozoic
of western North America by a number of species. About
18 or 20 species and subspecies have been recorded as
occurring in the Cenozoic of California and additional
species occur in the Tertiary strata of Oregon, Washington,
Alaska, and elsewhere.

Some authors have used Dall’s emendation of the
genus name, Pitaria, but as mentioned by Iredale, 1924,
and Stewart, 1930, there appears to be no justification
for this. Pitar, according to authorities on the classical
languages is correct as it stands. In the Sanscrit language
Pitar means father, according to Baugh (890). It is inter-
esting to note that the word “‘Pitar” also was used by
natives in the western Pacific (891).

Katherinella Tegland, (892), described as a sub-
genus of Pitar, with the type Pitaria arnoldi Weaver, differs
from typical Pitar in that the anterior lateral of the left
valve is small and extends from near the lower margin of
the hinge plate upward nearly to the junction of the
cardinals. The shell is thin and the valves are only moder-
ately inflated. This subgenus is known to occur only in
beds assigned to late Oligocene age, and to middle Mio-
cene age, in Oregon, Washington, and Alaska.

Pitar is represented in the late Pliocene and Quater-
nary in southern California by two species. Fourteen
species and subspecies were cited by Hertlein and Strong
as occurring in tropical and subtropical west American
waters and Olsson has added three more from northern
South America.

[Pitar newcombianus Gabb }

C[irce]. L[ioconcha]. newcombiana Gabb, Proc. Calif.
Acad. Nat. Sci., Vol. 3, p. 189, January, 1865.

(?]‘‘Callista sp. indet.’’ Dall, Proc. Calif. Acad. Sci., Vol.
5, p. 296, 1874. Well at San Diego. — Orcutt, West
Amer. Sci., Vol. 6, whole No. 46, p. 85, August, 1889.
Dall’s record cited. — Orcutt, cited by Ellis in Ellis and
Lee, U. S. G. S., Water Supply Paper 446, p. 59, 1919.

Callista newcombiana Gabb, Cooper, Calif. State Min.
Bur., Seventh Ann. Rept. State Mineral., p. 231, 1888.
“Pl. — San Diego well.” — Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 144, 1903. ‘Pliocene. — San Diego
well (Cooper).”

Pitaria newcombiana Gabb, I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 151, pl. 57,
fig. 2, 1924. ‘‘Pliocene at San Diego Well, California.”

Pitar newcombianus Gabb, Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 345, 1931. ‘Pliocene;
San Diego well, Balboa Park, San Diego (Cooper).”

Type specimen. — Location of type specimen un-
known to the present authors.

Type locality. —‘‘Hab. two valves, Catalina Island,
120 fms. Dr. Cooper.”

Range. — ? Late Pliocene, southern California, to
Recent. Recent from Monterey, California, to Punta

Penasco in the Gulf of California and south to Port
Guatulco, and Clarion Island, Mexico.

Occurrence in the San Diego Formation. — Based
upon records of Dall and Cooper.

Remarks. — Dall in 1874 mentioned a fossil bivalve

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

occurring in the San Diego well as “Callista sp. indet.
Smooth, inflated, thin; much like Callista newcombiana,
erroneously described as Lioconcha by Gabb” (893).
Cooper in 1888 cited ‘‘Callista newcombiana Gabb” from
the San Diego well, and most subsequent records in the
literature appear to be based upon his record. We have
not seen specimens of this species from the San Diego
Formation, and it has not been reported from strata of
Pliocene age in southern California. It may perhaps occur
in beds of that age, but for the present we are unable to
validate its occurrence at San Diego.

Records of the occurrence of this species in beds of
late Miocene age cited by Clark, 1914, and Weaver, 1950,
may be based upon some other species.

GENUS MEGAPITARIA GRANT AND GALE

Megapitaria Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 346, November 3, 1931. — Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 272, 1961. Type, by
original designation.

Type species (by original designation). — “Type,
Cytherea aurantiaca Sowerby” [Gen. Rec. and Foss. Shells,
Vol. 2, Pt. 33, pl. 196, fig. 3, 1831. (No locality cited.)
— Reeve, Conch. Icon., Vol. 14, Dione, species 12, pl. 3,
fig. 12, 1863 (as Dione aurantia). “Hab. Acapulco,
South America.” — Olsson, 1961, p. 273, pl. 46, figs.
1, la, le (as Macrocallista (Megapitaria) aurantiaca).
Lower California to northern Peru].

Range. — Pliocene to Recent. Recent from the inter-
tidal zone to 161 meters (88 fathoms).

Description. — Shells usually large or of moderate
size, thick, ovate-subtrigonal, ventricose, smooth, sculp-
tured only with fine lines of growth. Differing from
Pitar s. s. in the larger, thicker shell and in the deep pedal
retractor impression.

Remarks. — Shells of typical Megapitaria were
referred to Macrocallista Meek (894) in the earlier litera-
ture. They resemble that genus in general shell characters
but the valves are more ovate or circular in shape and
are less depressed. They resemble the genus Pitar Romer
which was described much earlier than Macrocallista but
they are much larger and thicker. Grant and Gale gave
an adequate discussion of Megapitaria which they compared
with other genera. This genus is based upon a west
American species and until the relations of the various
supra-specific groups of the Veneridae are more clearly
delimited, it seems best to apply Megapitaria to shells
similar to the type species.

Megapitaria squalida Sowerby
Plate 50, Figures 1-3

Cytherea squalida Sowerby, Proc. Zool. Soc. London for
1835, p. 23, issued April 16, 1835. — Sowerby, Thes.
Conch., Vol. 2, Cytherea, p. 629, pl. 131, figs. 87,
88, 89, 1851. “California.” [Not the record ‘‘from
the Philippine Islands.” ]

Dione squalida Sowerby, Reeve, Conch. Icon., Vol. 14,
Dione, species 10, pl. 3 fig. 10, 1863. “Hab. Cali-
fornia”. [Not the record “Philippine Islands.” ]

Pitar (Megapitaria) squalidus Sowerby, Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 347, 1931.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Various localities cited, Pliocene to Recent.

Megapitaria squalida Sowerby, Hertlein and Strong, Zoo-
logica, Vol. 33, Pt. 4, p. 168, 1948. “Range: Scam-
mon Lagoon, Lower California, to the Gulf of California
and south to Mancora, Peru.” — Keen, Sea Shells of
Tropical West America (Stanford Univ. Press: Stanford,
California), p. 134, fig. 303, 1958. [Same range as in
preceding reference. ]

Macrocallista (Megapitaria) squalida Sowerby, Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 273, pl. 46, figs. 2, 2 a-c,
1961. Lower California to northern Peru.

Type specimen. — British Museum (Natural History).

Type locality. — “Hab. ad Sanctam Elenam.”
“Found in sandy mud at a depth of six fathoms.”

Range. — Middle Pliocene to Recent. Recent from
Cedros Island, Lower California, Mexico, to the Gulf of
California, and south to Mancora, Peru; on sandy mud
flats to a depth of 161 meters (88 fathoms).

Occurrence in San Diego Fm. — L.A.M. 302.

Original description. — Cyth. testa ovato-subcordata,
crassiuscula, laevi, pallidé fusca, nonnunquam maculis
irregularibus saturatioribus; epiderme fusca; latere postico
longiore, prope partem bentralem subacuminato: long.
2.7, lat. 1.3, Alt. 2. poll. (Sowerby.)

Remarks. — Three valves of this species, the largest,
a right valve about 61 mm long, are present in the col-
lections of the Los Angeles County Museum from Loc.
302 (LAM). These fossils agree in all details with Recent
specimens of this species. A fragment from Loc. 122,
Pacific Beach, may have come from beds of Pleistocene
age.

This is the first record of Megapitaria squalida from
the San Diego Formation. It has been reported with ques-
tion from Strata of Pliocene age and definitely from beds
of Pleistocene age in southern California. It also has been
recorded from Pliocene to Recent in Lower California
and in Ecuador. Recent specimens 116 mm long have
been reported from the Gulf of California.

Megapitaria squalida differs from the similar M.
aurantiaca Sowerby which lives in the same region, in
that the shell is more produced both anteriorly and pos-
teriorly and in that it possesses a shiny purplish-brown
or spotted or striped periostracum rather than dull orange
brown.

GENUS COMPSOMYAX STEWART

Compsomyax Stewart, Acad. Nat. Sci. Philadelphia, Spec.
Publ. No. 3, p. 224, August 9, 1930. — Grand and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, Pp: O00;
1931. Type as indicated by Stewart.

Type species (by original designation). — “Type
species, Saxidomus gibbosus Gabb (= V. subdiaphana
(Carpenter).” [Geol. Surv. Calif., Palaeo., Vol. 2, p. 58
pl. 16, figs. 18, 18a, 18b, 1869. ‘““Common in the Pliocene
of Eagle Prairie, Humboldt County.” Also illustrated by
Stewart, 1930, pl. 14, fig. 6 (lectotype). |

Range. — Early (895) or middle Miocene (Temblor)
to Recent, western North America. Japan, Miocene.
Recent from 2 to 548 meters (1 to 300 fathoms).

Original description. — “This species differs from
typical Venerella in having a strongly bifid posterior right
cardinal.”

269

Remarks. — The type species of Compsomyax was
originally described under the genus Saxidomus, later
placed in Marcia H. and A. Adams, in Venerella Cossmann,
and finally Compsomyax was proposed for it by Stewart.
This in turn has been cited as a subgenus of Venerella
and Katherinella and in some cases has received the rank
of genus.

The hinge of Compsomyax lacks an anterior lateral
tooth in the left valve which separates it from Pitar Romer
and Katherinella Tegland (896). Both Compsomyax and
Katherinella occur in strata of middle Miocene age in
Washington. It has been suggested by some authors that
Compsomyax originated from Katherinella by the disap-
pearance of the anterior lateral tooth on the left valve.
The hinge bears a resemblance to that of Clementia
Gray but the posterior cardinal tooth of Compsomyax is
much more deeply bifid. Furthermore the shells referable
to Gray’s genus are undulated and possess a deeper pallial
sinus. Marcia H. and A. Adams, type designated by
Kobelt (897), Venus pinguis Chemnitz from East Indian
seas, belongs to a different group from Compsomyax.

Venerella Cossmann (898) has been discussed by
Stewart (1930, pp. 223-224), who placed Compsomyax
as a subgenus of it. We have examined a specimen of the
type species of Venerella from Hervelon near Hermonville,
France, of middle Eocene age, sent to us_ by Mr. J. L.
Staid. Stewart remarked on the small size of European
species of this group, and this observation is borne out
by the present specimen which is 14.2 mm long and 11.3
mm high, convexity (both valves together), approximately
7.5 mm. A comparison of the hinge of this specimen with
that of Compsomyax subdiaphana reveals that the poster-
ior cardinal of the right valve is not bifid and the middle
cardinal is more broadly trigonal in shape in comparison
to those of the corresponding ones on Carpenter’s species.

A consideration of these facts leads us to assign
Compsomyax generic status.

Compsomyax subdiaphana Carpenter
Plate 47, Figures 4, 7; Plate 57, Figure 15

Clementia subdiaphana Carpenter, Rept. Brit. Assoc. Adv.
Sci. for 1863, pp. 602, 607, 640, issued August, 1864.
Reprint in Smithsonian Mise. Coll., No. 252, pp. 88,
93, 126, 1872. — Carpenter, Proc. Acad. Nat. Sci.
Philadelphia, Vol. 17, p. 56, 1865. [Full description. ]
“In sinu Pugetiano. . .” — Dall, Proc. U. S. Nat. Mus.,
Vol. 1, p. 28, 1878. San Diego well. — Cooper, Calif.
State Min. Bur., 7th Ann. Rept. State Mineral, Vol.
7, p. 235, 1888. “Pl. — San Diego well.” — Orcutt,
West Amer. Sci., Vol. 6, Whole No. 46, p. 86, 1889.
Dall’s record (1878) cited. — Dall, Proc. U.S. Nat. Mus.,
Vol. 14, No. 849, p. 185, pl. 7, figs. 5, 6, 1891. Various
localities, from Port Etches, Alaska, to near entrance
of San Francisco Bay, California, in 14-16 fathoms,
Recent. — Orcutt, cited by Ellis in Ellis and Lee,
U. S. G. S., Water Supply Paper 446, p. 60, 1919.
Dall’s record (1878) cited.

Callista subdiaphana Carpenter, Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 144, pl. 13, fig. 4 (“‘Pliocene, Deadman
Island.”’), 1903. “Pliocene. — San Diego well (Cooper).”
Also Pleistocene and Recent.

Marcia subdiaphana Carpenter, Dall, Trans. Wagner Free

270

Inst. Sci., Vol. 3, Pt. 6, p. 1321, October, 1903. Refers
to Cooper’s record from “Pliocene of San Diego,
California.” — I. S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 155, pl. 33, fig. 1; pl. 38, fig.
1, 1924. Range, Sannakh Islands, Alaska, to Santa
Barbara Islands and San Pedro, California, Recent. —
Hertlein, Stanford Univ. Bull., Ser. 5, No. 79, p. 84,
1929. “San Diego Pliocene.” Also in Elsmere, Pico,
and Holser canyons, Pliocene.

Clementia (Compsomyax) subdiaphana Carpenter, Grant
and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p.
334, pl. 17, figs. 10a, 10b, 715, 1931. “San Diego
well (Cooper).” Also earlier records.

Compsomyax subdiaphana Carpenter, K. V. W. Palmer,
Geol. Soc. Amer., Mem. 76, p. 93, pl. 10, figs. 1-6,
1958. (Type specimen illustrated.)

Type specimen. — No. 4541, United States National

Museum.

Type locality. — “Recent. Puget Sound, Washington

(type).” (Palmer, 1958.)

Range. — Late Miocene; Pliocene to Recent. Recent
from Sannakh Islands, Alaska, to Cedros Island, Lower

California, Mexico, in 2 to 548 meters (1 to 300
fathoms).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 1404, 28889. L.A.M. 104, 107, 305,

305A. S.D. 75, 294, 295, 302, 2359.

Original description. — “‘Intermediate between Cle-
mentia proper and the prora group of thin Callistae”’
(1864, p. 602). ‘Hinge normal, very thin, ashy” (1864,
p. 640).

Supplementary description. — ?C. t. ovali, quoad
genus valde transversa, tumida, tenuissima; pallide cinerea,
epidermide pallide straminea; subdiaphana, sed subcal-
carea, haud porcellana; laevi, nisi striis incrementi; haud
lunulata, umbonibus satis prominentibus: intus, valva
dextra, dentibus anticis cuobus acutis, contiguis, elevalis,
postico elongato, acuto, bifido, ligamento parallelo; valva
sinistra dentibus anticis duobus, umbonem versus junctis,
acutis, divergentibus, postico elongato, acuto, simplici;
sinu palii, ut in Dosinia, angusto, angulato, per dimidium
interstitii umbones versus porrecto. Long. .72, lat. .58,
alt. .34. (Carpenter, 1865.)

Remarks. — The largest and best preserved specimen
of this species in the collections at hand is one from Loc.
1404 (CAS), embankment at the corner of India and Upas
streets in San Diego. It is 41.4 mm long, 36 mm high,
the convexity (both valves together), 24.6 mm.

A number of specimens are in the collections of the
Los Angeles County Museum, one of the largest is about
35 mm long. A left valve from Loc. 305 (LAM), although
not perfectly preserved, retains much of the hinge which
is identical with that of Recent C. subdiaphana of compa-
rable size.

There is considerable variation in convexity and in
the proportion of length to height in a series of Recent
shells of this species. A large specimen in the collections
of the California Academy of Sciences from Loc. 5084
(CAS), Port Ludlow, Puget Sound, Washington, is 68.8
mm long, 58 mm high, convexity (both valves together),
40.5 mm. A more elongate specimen from Loc. 19689
(CAS), San Juan Islands, Puget Sound, is 65 mm long,
48.6 mm high, convexity (both valves together), 36.4 mm.
The shape and the general characters of the thin-shelled

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

fossils from the San Diego Formation are similar to those
of Recent C. subdiaphana of comparable size.

Compsomyax subdiaphana is not certainly known
to occur in beds earlier than of Pliocene age. Records of
this species in beds of Miocene age in some cases are
doubtful because some of these occurrences involve the
species described as Cytherea oregonensis Conrad, a mid-
Miocene species which Etherington (889) believed to be
referable to the genus Pitar. Moore (900), who examined
Conrad’s type specimen of that species considered it to
be a “nomen dubium.’’ The species illustrated by Dall,
1909, under the name of Marcia oregonensis Conrad from
strata of Pliocene age at Coos Bay, Oregon, is referable
to C. subdiaphana. The species described by Conrad from
Miocene beds at Astoria, Oregon, under the names of
Venus angustifrons (901) and Venus brevilineata (902)
(the latter considered by Etherington to be a variety of the
former), are Miocene relatives of C. subdiaphana. Ethering-
ton believed these differed from the Recent species in
shape, and “‘in the absence of the sunken area just anterior
to the beak.” A fossil cited as ‘Marcia augustifrons
(Conrad)”’, the identification attributed to Durham and
Kirk, was cited by Travis (903) as occurring in the Merced
beds of Pliocene age in the southwestern portion of the
Sebastopol quad. in north central California. Some
specimens of Compsomyax from strata of Miocene age in
Oregon and Washington are very similar to the Recent
form. In general, the Recent shells appear to possess a
wider ligamental area between the two valves noticeable
when viewed from above.

Woodring (904) mentioned that two species, Lutra-
ria? traskei and Dosinia longula, from the late Tertiary of
California described by Conrad in 1856, may be closely
comparable to C. subdiaphana but that the types of the
two fossils ‘‘are so inadequate that the names may be
considered nomina dubia.” Grant and Gale (1931, pl.
22, fig. 1) published an illustration of the holotype of
Dosinia longula which, unless deformed, does not closely
resemble typical C. subdiaphana.

The species described as Saxidomus gibbosus by
Gabb (905) from the Pliocene of Humboldt Co., Calif., was
based on a large, globose form of Carpenter’s species.
Most authors do not consider it to be of taxonomic
significance.

The form described as Callista subdiaphana var.
pedroana by Arnold (1903, p. 144, pl. 13, fig. 2) from
the Lower San Pedro beds at San Pedro, California,
of Pleistocene age, is generally considered to be only a
small valve of Compsomyax subdiaphana.

Clementia obliqua Jukes-Browne (906), described
from ‘Porto Rico” (mistaken locality), is identical with
Carpenter’s species.

Species very similar to Compsomyax subdiaphana
occur in the Miocene of Japan. The species described
as Meretrix iizukai Yokoyama (907), as pointed out by
Stewart, is remarkably similar in shell characters observ-
able in the illustrations. More recently ““Clementia (Comp-
somyax) subdiaphana yazawaensis Otuka” (908) and
“Clementia (Compsomyax) aff. subdiaphana Carpenter”
(909) have been cited by Otuka from the Miocene of
Japan.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

GENUS SAXIDOMUS CONRAD

Saxidomus Conrad, Jour. Acad. Nat. Sci. Philadelphia,
Vol. 7, Pt. 2, p. 249, 1837. Sole species, Saxidomus
nuttalli Conrad. — Dall, Proc. U. S. Nat. Mus., Vol. 26,
No. 1312, p. 356, 1902. “Type, S. nuttallii Conrad.” —
Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 6, p.
1280, 1903. —- Grant and Gale, Mem. San Diego Soc.
Nat. Hist., Vol. 1, p. 341, 1931.

Type species (by monotypy). — Saxidomus nuttalli
Conrad.

Range. — Early Miocene to Recent. Recent from
San Quintin, Lower California, Mexico, to Japan. ?Chile.
Recent from the intertidal zone to 37 meters (20 fathoms).

Description. — Shell large, rude, chalky, ovate-
quadrate, with low beaks, and concentric usually feeble
sculpture; the ligament is strong and not depressed; there
is no defined lunular area or escutcheon; internal margins
smooth; pallial line with a deep, rounded sinus; hinge
with three cardinals in each valve; the posterior right
cardinal bifid; anterior laterals closely adjacent to the
cardinals, one of the left ones often in line with the
anterior cardinal. (Dall, 1902).

Remarks. — The exact relationship of Saxidomus to
similar genera in the Veneridae is not certainly known.
Romer (910) long ago discussed this genus and the species
assigned to it. Grant and Gale ventured the opinion that
the cardinal teeth may have been multiplied by division
in a manner comparable to some of the paphias.

The earliest known species appear in the early
Miocene of California. Species assigned to Saxidomus
in beds of pre-Miocene age, such as “Saxidomus (?)
noblei”’ Dickerson (911), from the early Eocene of Calif-
ornia, are almost certainly referable to other genera. The
type of that Eocene species is poorly preserved and the
hinge is unknown.

We have examined a cast of the holotype of Saxi-
domus popofianus Dall (912) from beds of presumably
medial Tertiary age on the Shumagin Islands. The spe-
cies is based upon an internal cast about 51 mm long.
The pallial sinus is short, V-shaped, rounded at the end,
extending forward only about 19 mm from the posterior
end. We can add nothing concerning the affinities of this
form.

Saxidomus is represented in the late Tertiary of
California by four or five species and in the Pleistocene
by two. Two species and one subspecies now live in
west American waters in the region between Alaska and
northern Lower California. Two and perhaps three species
have been reported from strata of Miocene age in Japan.
One species now lives in Japanese waters.

This genus is generally considered to be limited in
distribution, both fossil and Recent, to the north and
northeast Pacific. The species described from Chile as
Venus opacus Sowerby (913) has been referred to various
genera by different authors. Romer, and later Carcelles
and Williamson (914), assigned it to Saxidomus. More
recently it was placed in Eurhomalea Cossmann (915)
by Soot-Ryen (916).

Von Ihering (917) believed that Saxidomus origi-
nated along the west coast of North America and that it
reached the southern portion of the west coast of South
America during the Pleistocene. We have not studied
specimens from Chile.

271

Key to Species And Subspecies of Saxidomus

A. Anterior end broad and
long . . (subspecies) latus
B. Anterior end rather narrow

and short nuttalli

Saxidomus nuttalli Conrad

Sfaxidomus]. nutalli Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 249, pl. 19, fig. 12,
1837. — J. P. Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol.
3, pp. 174, 182, 1912. ‘San Diego — Purisima.”’ —
Weymouth, Calif. State Fish Game Comm., Fish Bull.
No. 4, p. 35, pl. 7, figs. 1 and 2, 1920. “Bolinas
Bay to San Diego,” California. — Grant and Gale,
Mem. San Deigo Soc. Nat. Hist., Vol. 1, p. 341, pl. 18,
fig. 11, 1931. Late Miocene to Recent, California. —
Fitch, State Calif. Dept. Fish Game, Fish Bull. No. 90,
p. 64, fig. 30, 1935. “Humboldt Bay, California, to
San Quintin Bay, Baja California,” Recent. — Abbott,
American Sea Shells (D. Van Nostrand Co., Ine.;
New York), p. 417, pl. 31, fig. 1, 1954. ‘‘Humboldt
Bay, California, to Lower California.

Type specimen. — Two syntypes No. 43.12.6.76
and 55.3.14.48, British Museum (Natural History) (A. M.
Keen, Veliger, Vol. 8, No. 3, p. 169, 1966).

Type locality. — “Inhabits the coast of California
and Sta. Diego, burrowing into soft clay-stone accompany-
ing the Pholades, Cummingae, & c.”

Range. — Middle Miocene (Temblor (918); Topanga)
to Recent. Recent, Humboldt Bay, California, to San
Quintin Bay, Lower California, Mexico. In bays and
lagoons at depths of 12-18 inches in sandy mud or sand
which is usually exposed at low tide. To a depth of 37
meters (20 fathoms).

Occurrence in San Diego Fm. — “San _Diego-
Purisima” (J. P. Smith). L.A.M. 305A, 318, 319, P.87:
58442. U.C.L.A. 312, 1386.

Original description. Shell suboval; disk rough,
with concentric striae, elevated on the posterior slope;
posterior extremity truncated; colour white, with brown
spots and stripes about the umbo and ligament margin.
Length, two inches. (Conrad.)

Remarks — Several specimens of this species are
present in the collections of the Los Angeles County
Museum from near the Mexican boundary. Three of
these from Loc. 319 (LAM) retain both valves, the largest
is 119 mm long, 89 mm high and the convexity (both
valves, somewhat compressed together), 59 mm. Some
of the valves are 4 mm thick. The anterior portion of a
valve from Loc. 318 (LAM), is 101 mm long, 89 mm high,
the convexity, approximately 29 mm. Three specimens
of this species, also from near the Mexican boundary, are
in the collections of the University of California at Los
Angeles. The shell characters of all these specimens are
similar to those of Recent Saxidomus nuttalli.

An imperfect cast from Sand Rock Canyon, San
Diego, 64.2 mm long, in the collections of San Diego
Society of Natural History is probably referable to S.
nuttalli.

The generally more northern species Saxidomus

272

giganteus Deshayes (919) has a generally smaller, more
rounded, much smoother shell.

Saxidomus vaquerosensis Arnold (920), described
from beds of middle Miocene age, has a narrower outline
and more regular and finer concentric sculpture, and, ac-
cording to its author, is probably the precursor of S.
nuttalli. ‘‘Saxidomus cf. vaquerosensis Arnold” was re-
corded by Hertlein and Jordan (921) from beds of middle
Miocene age in Lower California.

Khomenko (922) cited a species under the name of
S. vaquerosensis from the Matchgar series, which he
considered to be of early Miocene age on the Schmidt
Peninsula, Kamtschatka. Confirmation of this identifica-
tion or of close relationship with the west American species
is desirable.

A species from beds of Miocene age in Japan, cited
by Nomura and Hatai under the name of “Saxidomus
Nuttallii Conrad” was later named Saxidomus nomurai
by Hatai and Nisiyama (923).

Saxidomus nuttalli reaches a length of about 171
mm (7 inches). Smith (924) discussed the ecology and
growth of this species.

Gavala y Laborde (925) believed that resemblance
existed between Cochlea gilua Martyn (926) from Poulo
Condore Islands in the South China Sea, South Vietnam,
and Saxidomus nuttalli Conrad illustrated by Sowerby
(Thes. Conch., Vol. 2, pl. 164, fig. 10). However, an
inspection of Martyn’s illustration supports Solem’s as-
signment of the East Indian species to a different genus
and family (see Trapezium sowerbyi Hidalgo, Solem,
Proc. Malacol. Soc. London, Vol. 31, Pt. 2, p. 70, pl. 5,
figs. 1, 2, 1954).

Saxidomus nuttalli latus Stewart
Plate 50, Figures 8, 10

Saxidomus nuttalli latus Stewart, in Woodring, Stewart,
and Richards, U. S. G. S., Prof. Paper 195, p. 94, pl.
8, fig. 15; pl. 16, fig. 8 (as Saxidomus nuttallii latus);
pl. 33, fig. 6, 1940, issued June 7, 1941.

Saxidomus sp. aff. S. nuttalli Conrad, Moore, San Diego
Soc. Nat. Hist., Occas. Paper 15, p. 52, pl. 24, figs.
a, b, 1968. ‘Pliocene in Balboa Park, San Diego.”

Type specimen. — No. 495782, United States Na-
tional Museum.

Type locality. — Loc. 87(U.S.G.S.), “North Dome,
sec. 9, T. 22 S., R. 18 E.; 1,520 feet north, 625 feet east;
divide between Arroyo Pequeno and Arroyo Finito,”
Kettleman Hills, San Joaquin Co., California. San Joaquin
Formation, late Pliocene.

Range. — Etchegoin, San Joaquin, and San Diego
formations, middle Pliocene, California.

Occurrence in San Diego Fm. — C.A.S. 12051.
S.D. 70.

Original description. — “. . . .has a wider and longer
anterior end than the living California S. nuttalli.”’

Remarks. — Two valves of this subspecies are pre-
sent in the Henry Hemphill collection from the San Diego
well. The larger valve, a right valve, 119 mm in length,
is imperfect; lacks the ventral portion of the valve but
the anterior dorsal margin is more flaring, broader, and
the posterior dorsal margin is straighter than that of Recent
Saxidomus nuttalli Conrad. Probably some variation
exists in a series of specimens. Stewart mentioned that

‘

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

“some specimens from the upper Mya zone have smaller
adductor scars and a shallower pallial sinus than the
Recent form, but the figured specimen from that hori-
zon has a deep pallial sinus.”

Another feature noticed on the larger valve at hand
is the prominent and longer nymph plate and this no
doubt is because of the straighter dorsal margin on the
subspecies. This specimen agrees well with Stewart’s
illustrations (especially his plate 16, figure 3).

The enumerated differences characterizing the sub-
species are more noticeable on larger than on smaller
specimens. A left valve from the San Diego well, length
72 mm, height, approximately 51 mm, apparently has a
straighter posterior dorsal margin than that on Recent
specimens of comparable size.

GENUS CHIONE MEGERLE VON MUHLFELD

Chione Megerle von Miuhlfeld, Gesellschaft Naturf.
Freunde zu Berlin, Jahrg. 5, p. 51, 1811. Species
cited: ‘“‘Chione Dysera” with references to “Linn.
Syst. Nat. Gen 309. Sp. 4.a” and ““Chemn. Conch. 6.
t. 28. f. 287-290”; “‘Chione Gallina” with references
to “Linn. Syst. Nat., Gen 309, Sp. 9, beta 114.a” and
“Chemn. Conch. 6. t. 30, f. 308-310.’ — Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 318
1931. Type as indicated by Gray.

Type species (designated by Gray, Proc. Zool. Soc.
London for 1847, p. 183). —‘“‘Chione Dysera” [Linneasu].
[The figure cited by Linnaeus (Syst. Nat., p. 685, 1758)
to represent typical Venus dysera was based on Argenville,
Conch., pl. 24, fig. K, which may represent Venus plicata
Gmelin (Linn. Syst. Nat., ed. 13, Tom. 1, Pars 6, p.
3276, 1791. “in mari indico”. References to “Argenv.
Conch. t. 21. f. k”, “Valent. Abh. t. 15, f. 21.”, ““Chemn.
Conch. 6. t. 28. f. 295-297.”). The figures cited by
Megerle von Muhlfeld as representing Venus dysera are
those of Chemnitz (Syst. Conchyl.-Cab., Bd. 6, pl. 28,
figs. 287-290, 1792) with the localities (p. 296) “‘westin-
dischen Strande” and “Jamaica’’. These figures represent
Venus cancellata Linnaeus (Syst. Nat., ed. 12, p. 1130,
1767. “Habitat in Oceano Africano.” Reference to
Gualtieri, Test., pl. 88, fig. D.), the species traditionally
accepted as type of Chione. We follow this practice at
least until a definite settlement of the selection of the
type species is sanctioned by the Internatl. Comm. of
Zool. Nomencl. Dodge (Bull. Amer. Mus. Nat. Hist., Vol.
100, Art. 1, pp. 89-92, 1952) has given a full discussion
of the problem of the type species of Chione. Venus
cancellata Linnaeus is well illustrated by K. V. W. Palmer
(Palaeontogr. Americana, Vol. 1, No. 5, p. 359 (151), pl.
68 (37), figs. 1-6, 6a, 7, 8, 11, 15, 1927), with the
range from Cape Hatteras, North Carolina, to Brazil, the
Gulf of Mexico, and West Indies). ]

Range. — Late Oligocene or early Miocene to Re-
cent. Recent in warm temperate and tropical waters,
from the intertidal zone to 232 meters (127 fathoms).

Description. — Subtrigonal, thick, anteriorly round-
ed, posterior ventral margin somewhat pointed, beaks
prosogyrous; lunule and escutcheon well defined; con-
centric lamellae well developed, and may or may not be
crossed by radial sculpture; radial ribs usually present;
ligament sunk below escutcheon; hinge of left valve with

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

2 or 3 cardinals, the posterior one usually bifid, right
valve with 3 in addition to a posterior ridge, the anterior
one small, the middle and the posterior ones large, usually
slightly grooved; pallial sinus short; inner margins of the
valves finely crenulated.

Remarks. — About 30 species and 7 subspecies of
Chione have been described from the Cenozoic of western
North America. Many of these species have been discussed
and illustrated by Parker (927). Some of the tropical
species were separated later into different genera by
Olsson (1961). Three species are known to occur in the
San Diego Formation.

The earliest occurrence of Chione s. s. in southern
California is in strata of middle Pliocene age. Species of
this subgenus now live in tropical, subtropical and warm
temperate American waters. Two species of this subgenus
range north to Point Mugu, California (34° N.) but during
Pleistocene time one of these ranged north to Tomales
Bay (38° 10'N.). Chione fluctifraga Sowerby, the type
of Chionista Keen, ranges north to Morro Bay, San Luis
Obispo Co., at the present time.

Anomalocardia Schumacher has a hinge similar to
that of Chione but the concentric sculpture is composed
of prominent, thick, concentric rugae rather than lamellae.
The concentric sculpture is predominant.

Iliochione Olsson (928) was recently proposed to
include tropical west American species formerly placed
in the genus Anomalocardia.

Key To Subgenera Of Chione

A. Ligament anteriorly extending deeply into the
valve and above the nymph; pallial sinus short but
well developed and angular at
theend . . Securella

B. Ligament extending only slightly into the valve
and onto the nymph; pallial sinus very short or
almost lacking, somewhat rounded at

the end. -Chione s. s.
SUBGENUS CHIONE S. S.
Key to Species of Chione s. s.
A. Concentric lamellae evenly spaced; radial
ribs coarse . Pare . undatella
B. Concentric lamellae very closely crowded;
radial ribs fine allisoni

Chione (Chione) allisoni n. sp.
Plate 51, Figures 11-16

Description. — Shell of holotype (a left valve) of
medium size, elongately trigonal, moderately thin, moder-
ately convex; sculpture consisting of rather fine radial
ribs which may be bifid or trifid, these are crossed by
thin, low, concentric lamellae, moderately spaced on the
early portion of the valve, but over most of the shell these
are very closely spaced; lunule with fine sculpture similar
to the remainder of the valve; escutcheon on left valve,

273

smooth, steeply sloping; hinge with a thin anterior cardi-
nal which slopes forward, a fairly thick central tooth
and a narrow posterior ridge which extends from beneath
the beak almost to the dorsal margin of the hinge plate;
pallial sinus very short, pointed; interior margin finely
denticulated. Right valve (paratype) similar to the left
except that the escutcheon is less well developed and on
some valves less well defined; hinge with a short anterior
tooth fused to the lunular margin, central and posterior
teeth well developed. Dimensions of the holotype, length
32.6 mm, height 27.2 mm, convexity (one valve) 10.2 mm.

Holotype, a left valve, and paratypes, in the collec-
tion of the San Diego Society of Natural History. Para-
types, in the collection of the San Diego Society of
Natural History. Paratypes also deposited in the Depart-
ment of Geology, California Academy of Sciences, and
in the Los Angeles County Museum.

Type locality. — Loc. 222 (San Diego State College),
two miles south-southeast of Mt. Soledad and 200 yards
north of Kate Sessions Elementary School; shell bed
exposed at middle of south facing bank (about six feet
above house level) at rear of lot on northeast corner
of Edgeworth Road and Blackmore Court, community
of Pacific Beach, city of San Diego, collected by Charles
N. Howell, 1964.

Range. — Known only from the type locality and
vicinity.

Occurrence in San Diego Fm. — S.D.S.C. 222,
223.

Remarks. — About 75 valves of this species have
been available for study. The largest specimen, a right
valve from Loe. 222 (SDSC) is 35.4 mm long and 31.8
mm high. A more rounded specimen from Loc. 223
(SDSC), is 31.4 mm long and 31.2 mm high. In general
the shells are longer than high.

The shape and general appearance of the valves are
somewhat similar to that of Chione undatella Sowerby.
However, all specimens of this new species differ form
C. undatella in the thinner shell, finer radial ribs, and
fine, low, extremely closely spaced concentric lamellae.
One specimen in the lot has rather coarse radial ribbing
and in shape somewhat resembles that of C. californiensis
gealeyi Parker (929).

The generally fine radial ribbing and low, closely
spaced, concentric lamellae, lend a general resemblance
to Chione (Nioche) asperrima Sowerby (930), the type
species of Nioche Hertlein and Strong. However, the
general shape, lack of radial ribs along the posterior
dorsal margin, the kind of sculpture on the early portion
of the valves, as well as the short pallial sinus, all more
closely resemble those features on C. undatella than on
any other species. For this reason we assign the new
species here described to Chione s. s. rather than to
Nioche Hertlein and Strong.

This species is named for the late Dr. Edwin C. Alli-
son, Department of Geology, San Diego State College in
recognition of his contributions to the knowledge of the
stratigraphy and paleontology of Lower California.

Chione (Chione) cf. C. (C.) undatella Sowerby

The following references, type specimen, type
locality and description refer to typical C. undatella.

274

Venus undatella Sowerby, Proc. Zool. Soc. London, p.
22, April 6, 1835. — Sowerby, Thes. Conch. Vol. 2,
p. 711, pl. 153, fig. 22, 1853. “Found on the shore at
the island of Tres Marias, Gulf of California.”

Venus neglecta Sowerby, Beechey’s Voy., p. 151, pl. 41,
fig. 8, 1839. “Inhabits sandy mud on the coast of
Central America.”

Venus simillima Sowerby, Thes. Conch., Vol. 2, p. 708,
pl. 153, figs. 17, 18, 1853. “California.” — Reeve,
Conch. Icon., Vol. 14, Venus, species 44, pl. 13, fig.
44,1863. “Hab. San Diego, California.”

Chione undatella Sowerby, Hertlein and Strong, Zoologica,
Vol. 33, pt. 4, p. 182, 1948. “Mugu Point, California,
to Paita, Peru.”

Chione (Chione) undatella Sowerby, Parker, Jour. Paleo.,
Vol. 23, No. 6, p. 581, pl. 89, fig. 1; pl. 90, figs. 12,
13, 1949. Recent, Cedros Island, Lower California, to
Panama. Pleistocene, San Pedro, California. Late
Pliocene and early Pleistocene of the Gulf of California
and the Galapagos Islands.

Type specimen. — British Museum (Natural History).

Type locality. — “Hab. in Sinu Californiensi. (Island
of Tres Marias.)” ‘“‘Found on the shore.”

Range. — Middle Pliocene to Recent. Recent, Mugu
Point, California, to Panama and the Galapagos Islands;
from the beach to 91 meters (50 fathoms), usually on
sand or sandy mud bottom.

Occurrence in San Diego Fm. — L.A.M. 302, 305.

Original description. — Ven. testa rotundato-ellip-
tica, crassa, albida, fusco maculata punctata et undatim
picta, costellis radiantibus confertis, aliisque decussantibus
undulatis sublamellosis; latere antico breviore, postico
subdeclivi, marginibus depressis; margine ventrali rotun-
dato, intus crenulato: Long. 1.6; lat. 1., alt. 1.5 poll.
(Sowerby.)

Remarks: The specimens here provisionally referred
to Chione undatella are fragments the largest of which,
the umbonal portion of a right valve 22mm high, retain
the hinge. These were embedded in matrix along with
Megapitaria squalida, Anadara_trilineata, and Pecten
healeyi. The shell characters, especially the sharp, evenly
and rather closely spaced concentric lamellae, are identical
with Recent specimens of C. undatella from San Ignacio
Lagoon, Lower California, and elsewhere.

The shell of this species is similar to that of C.
californiensis Broderip (931) but the valves are generally
slightly more inflated and ornamented with sharper, more
numerous, more closely spaced concentric lamellae, about
4 to 6 per centimeter on the middle of a valve.

Study of a large series of specimens of the present
species reveals so much variation that we are inclined to
refer numerous named variants to C. undatella including
Venus neglecta Sowerby, 1835; Venus nuttalli Conrad,
1837; Venus entobapta Jonas, 1845; Cytherea sugillata
Jonas, 1845; Venus perdix Valenciennes, 1846; V. simil-
lima Sowerby, 1853; V. excavata Carpenter, 1857; V.
bilineata Reeve, 1863; Chione undatella var. taberi Parker
1949.

SUBGENUS SECURELLA PARKER
Securella Parker, Jour. Paleo., Vol. 23, No. 6, p. 587,

November, 1949.
Type species (by original designation). — ‘“Geno-

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

type. — Venus securis Shumard (Pl. 94, figs. 8, 12, 19;
pl. 95; pl. 95, fig. 6).””. [Venus securis Shumard, Trans.
Acad. Sci. St. Louis, Vol. 1, No. 2, p. 122, 1858. “Col-
lected by Dr. Evans in gray, fine-grained sandstone of
the Miocene age, at the mouth of Coos Bay, Cape Blanco,
and on the shores of the Columbia short distance above
Astoria, Oregon Territory. At all of these localities
it is quite common.” — Dall, U.S. G. S., Prof. Paper No.
59, p. 120, pl. 11. fig. 8; pl. 13, figs. 2, 8, 9, 1909 (as
Chione securis). Coos Bay, Oregon, late Miocene [Plio-
cene]. (A reprint of Shumard’s original description on
pp. 187-188).— Trumbull, Jour. Paleo., Vol. 32, No. 5,
p. 903, pl. 117, figs. 1-3, September, 1958 (as Chione
(Securella) securis. Lectotype and hypotype illustrated).

Range. — Late Oligocene to middle Pliocene, north-
eastern Pacific, Alaska to California; Kamtschatka, and
Japan.

Original description. — Ligament deeply sunken in
shell, wedging out between hinge plates; right, middle
and posterior cardinals slightly grooved; left middle
cardinal deeply grooved so that posterior portion of tooth
larger and higher than anterior; sculpture of evenly spaced
thin concentric ridges arising from a layer of concentri-
cally disposed shelly material; this layer underlain by
distinct radial ribs not visible on the surface; this condi-
tion of exclusively concentric ribs usually modified by
erosion of shell, so that the common worn and leached
specimens exhibit ornamentation with varying degrees of
prominence and numbers of radial and concentric ribs;
lunule deeply impressed, it is never removed, but escutch-
eon is often obliterated at an early state by erosion. For
hinge characters, see also S. ensifera (Dall) (pl. 89, fig. 4).
(Parker.)

Remarks. — The smooth surface on uneroded shells,
crossed only by concentric lamellae, is a shell character
which serves to separate this subgenus from Chione s.s.
and Chionopsis Olsson. The thin, erect, concentric lamel-
lae of Securella are quite different from the thicker,
curved lamellae of Lirophora Conrad. The deep ligamental
grooves which wedge out under the posterior dorsal mar-
gins of the valves are quite different from the correspond-
ing grooves of the other subgenera of Chione mentioned
above. Thirteen species from the medial Tertiary of the
western United States were referred to Securella by Parker.

Chione (Securella) kanakoffi n. sp.
Plate 49, Figures 1, 3, 4, 5, 6;
Plate 51, Figures 4, 5, 6, 7, 10

Description. — Shell large, thick, ovately trigonal
in outline, evenly convex; beaks prosogyrous; anterior
end rounded and merging into the broadly rounded ventral
margin, posterior dorsal margin very gently rounded to
the posterior end which is very broadly rounded into the
ventral margin with only a faint trace of a posterior trun-
cation; lunule broadly cordate, concave, bounded by an
impressed line; escutcheon extends to the posterior end
and is crossed by concentric lamellae; a narrow, very
faintly depressed area extends parallel to and just anterior
to the posterior dorsal margin; sculpture consists of thin
concentric lamellae spaced about 5 or 6 mm apart over
much of the valve but more closely spaced toward both
ends and along the ventral margin, the areas between the
lamellae are smooth but radial riblets are exposed where

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

the surface is eroded, these are fine on the umbo but
coarser toward the ventral margin. Dimensions: length
129 mm; height 122 mm; convexity (both valves together)
76 mm.

Hinge of right valve (paratype) with three cardinals,
the anterior one rather thin, the middle and posterior ones
fairly thick and medially grooved; a nymph plate about
equal in length to the posterior cardinal occurs above it;
a ligamental groove extends deeply under the dorsal
margin; the base of the hinge is decidedly convex (up-
ward) from below the middle cardinal to the posterior
margin; pallial sinus short, V-shaped and extends forward
44 mm from the posterior margin, and points toward about
the lower portion of the anterior adductor muscle im-
pression; adductor impressions large and deep; margin of
valve nearly smooth, with faint indications of radial
sculpture which is covered by a calcareous layer. Hinge
of left valve (paratype) similar to that of the right valve,
but with a thinner, faintly grooved posterior cardinal,
a fairly thick and medially grooved central one and a
fairly thick anterior cardinal.

On some specimens the ventral margin, where
eroded, is denticulated where the underlying radial sculp-
ture is exposed.

Type specimens. — Holotype, right valve, and
paratypes, Invertebrate Paleontology Collection, Los An-
geles County Museum.

Type locality. — Loc. 305C (LAM), exposure at
base of hill, 100 feet west and 440 feet south of the
northeast corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian (see U. S. G. S. topog., map,
San Ysidro quad., rev. 1953); G. P. Kanakoff, collector.
Paratype from Loc. 305 (LAM), 2400 feet east and 1350
feet south of the northwest corner of Sec. 8, T. 19 S.,
R. 2 W., San Bernardino Base and Meridian (see U. S. G. S.
topog. map, San Ysidro quad., ed. 1943); G. P. Kanakoff,
collector. Paratype from Loc. 305A (LAM), west side of
next gully east of Loc. 305 (LAM), at the same elevation;
fossils in float slump and consolidated boulders and silt
and sandstone, and silt in place; G. P. Kanakoff, collector.

Additional occurrences in the San Diego Fm. —
C. A. S. 1181, 28885, 28892. L. A. M. 305A, 318, 319.
Sa Dia Us Can At 294.7312 2359" S: Di S.'Cs32!

Range. — Known only from the type locality and
vicinity of San Diego.

Remarks. — This species is well represented in the
collections of the Los Angeles County Museum from
near the Mexican boundary by two specimens with both
valves together and by ten large single valves in various
states of preservation and by many fragments, and by
more than 100 small ones. The shell of one of the frag-
ments is 9 mm thick. The amount of radial sculpture ex-
posed on the exterior of the valves is in direct proportion
to the amount of erosion of the surface. Three fragments
of valves, the largest 90.5 mm long are present in the
collections of the University of California at Los Angeles
from the same area as well as one right valve in the
collections of San Diego State College. Small specimens
in the collections of the California Academy of Sciences
probably also came from near the Mexican boundary and
from other localities.

Chione kanakoffi n. sp. more closely resembles
Chione semiplicata Nomland (932), which was described
from beds of late Miocene age, than any described species.

275

It differs from that species in the more expanded and
rounded anterior end, the more evenly convex valves
and less flattened area along the posterior dorsal margin
and in the more widely spaced concentric lamellae.

Compared with Chione margaritana Anderson and
Martin (933), the shell of the new species is more orbicu-
lar in outline, the height is greater in proportion to the
length and the umbos are broader.

Compared to Chione panzana Anderson and Martin
(934) the valves of the new species are more highly convex,
the posterior end is more rounded, the lunule is broader
and the concentric lamellae are much more widely spaced.

Parker (935) placed C. margaritana in the synonymy
of C. panzana but a comparison of the type specimens of
these two species reveals that they apparently represent
distinct species. Two other elongate species, C. vickeryi
Wiedey (936) and C. schencki Loel and Corey (937),
described from beds of Miocene age, were considered by
Parker (1949, p. 584) to be founded upon deformed
specimens which he placed in the synonymy of C. semi-
plicata Nomland. The two specimens are no doubt some-
what deformed but whether they are identical with C.
semiplicata may be open to question.

A comparison of C. kanakoffi, new species, with C.
elsmerensis English (938) reveals that the shell of the new

pecies is more rounded posteriorly, and the radial
ribbing (exposed by erosion) is much finer.

Small specimens of this new species were cited by
the senior author (939) from the San Diego Formation
under the name of Chione fernandoensis English. More
than one hundred valves from Loc. 305A (LAM), 4 to
23 mm in length, of juvenile Chione kanakoffi n. sp.
have been available for study. These have been compared
with a cast of the specimen of Chione fernandoensis (940)
illustrated by English, later cited as the holotype by Parker,
and also with a cast of the specimen illustrated and cited
as a paratype by Parker. Keen and Bentson (941) evidently
considered these two specimens to be syntypes. We have
also had available for comparison specimens of C. fernand-
oensis from Loc. 710 (CAS), Elsmere Canyon, Los Angeles
Co., California.

None of the small specimens from the San Diego
Formation are definitely referable to C. fernandoensis and
we consider them to be juvenile forms of C. kanakoffi
ns Sp:

The general appearance of C. kanakoffi n. sp. is that
of a plumper form, more rounded, more convex, the beaks
more projecting and the posterior dorsal margin is not so
straight and not so strongly angulated and the lunule is
more depressed. The concentric lamellae on these juvenile
forms are often greatly eroded but there are about 10
to 18 on specimens 10.8 to 18 mm long. Some of these
valves were bored by gastropods.

Over fifty valves of a small species of Chione, 4 to
20 mm in length, from Loc. 291 (LAM), Pico Formation,
Humphrey’s quad., are identical with valves of the same
size from the San Diego Formation.

Parker (942) illustrated four specimens under the
name of Chione (Anomalocardia) fernandoensis. His
figures 14 and 16 of a specimen from Elsmere Canyon
apparently represent C. fernandoensis. His figures 13 and
18, indicated as a paratype, represent a specimen with
rather highly projecting umbos. This apparently represents
a different species resembling in general outline species

276

such as C. securis Shumard. Parker’s figures 7, 8, and
15 represent specimens of Pleistocene age and do not
closely resemble typical C. fernandoensis.

Chione mariae d’Orbigny (943) now living in tropical
west American waters, is more trigonal in outline and has
fewer concentric lamellae than either juvenile C. kanakoffi
n. sp., or C. fernandoensis.

GENUS PROTOTHACA DALL

Protothaca Dall, Proc. U. S. Nat. Mus., Vol. 26, No. 1312,
p. 364, December 29, 1902. — Frizzell, Proc. Geol.
Soc. Amer. for 1934, pp. 387-388, 1935. Type as
indicated by Dall. — Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 304, 1961. Original designation of type species
cited.

Type species (by original designation). — “Type
Venus thaca Molina (= V. dombeyi Lamarck).”’ [Chama
thaca Molina, Saggio sulla Storia Naturale del Chile, p. 178.
1782. See also English translation, Vol. 1, pp. 141, 243,
1808 (Middletown, Connecticut); a different edition,
1809, pp. 167, 287. — Olsson, 1961, p. 304, pl. 41, fig. 1;
pl. 53, figs. 1, la (as Protothaca (Prothothaca) thaca).
Lima, Peru, to Chile. Venus dombeii Lamarck, illustrated
by Reeve, Conch. Icon., Vol. 14, Venus, pl. 9, fig. 29,
April, 1863. “Hab. Valparaiso Bay; Cuming.” See also
Riveros Zuniga and Gonzales Reyes, Rev. Biol. Mar.,
Vol. 2, Nos. 2 and 3, p. 142, fig. 32 (p. 143 as Venus dom-
beyii), fig. 33 (as Venus thaca), fig. 34 (as Venus ignobilis).
Ancon, Peru, to Puerto Montt, Chile. ]

Range. — Eocene to Recent (Frizzell). Entirely or
almost entirely around the Pacific basin. Western North
America from middle Miocene (944) to Recent. Recent
from the intertidal zone to about 46 meters (25 fathoms).

Original description. — Shell ovate, convex, colora-
tion white or dull; surface dull, reticulately sculptured,
the radials usually stronger; sculpture more or less distinct-
ly divided into three areas, the middle of the valves with
chiefly radial, the anterior radial and scabrous, the poster-
ior with irregularly concentric sculpture; lunule and es-
cutcheon of the left valve, sharply circumscribed; in the
type species the right valve shows no escutcheon and the
margin partially overlaps that of the left valve but does
not conceal the ligament; middle cardinals grooved or
bifid; pallial sinus free, moderate, pointed in front; the
inner margins sharply crenulated in the typical section.
(Dall.)

Remarks. — Some of the west American species
assigned to Protothaca do not have coarsely crenulated
inner margins nor does the right valve overlap the left.
However, many others do have crenulated margins and
the right valve slightly overlaps the left one posteriorly.
This latter feature, although slight, is noticeable on some
specimens of Protothaca staminea, P. laciniata and P. grata.
For these reasons we leave P. staminea in the typical
subgenus of Protothaca.

Protothaca is confined in its distribution almost
entirely to the borders of the Pacific basin. Frizzell in
1935 stated that about 25 species of this genus were
known and several have been described since. Von Ihering
(945) stated that the genus occurred in the Eocene faunas
of Patagonia and that it reached California in the middle
Miocene. Later, Marwick (946) outlined the route of

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

migration to Japan in Pliocene time and to New Zealand
in the Pleistocene and this was accepted by Frizzell, 1935.
In the latest check list of the Tertiary mollusks of Japan
by Hatai and Nisiyama (947), three species assigned to
Protothaca are cited as occurring in strata of Miocene age
in that country.

Novathaca Habe (948) was proposed for Chione
euglypta Sowerby from Japan, a species somewhat similar
to Protothaca staminea Conrad.

A subgenus of Protothaca, Tropithaca Olsson (949),
was recently proposed with Protothaca grata Say, a west
American species, as type. The escutcheon is much re-
duced in size and the pallial sinus is shorter than that of
Protothaca s. s.

Tuangia Marwick (950), type Venus crassicosta Des-
hayes, which occurs in New Zealand, also is very similar
to Protothaca, but it has coarser sculpture than the west
American forms.

The crenulated inner margin, more distinct lunule
and narrower pallial sinus are features which serve to
separate Protothaca from Venerupis Lamarck.

Key to Subgenera of Protothaca

A. Sculpture coarse, the radial
usually the stronger; lunule well
defined; right valve sometimes
overlapping the left posteriorly;
valves decidedly inflated . Protothaca s. s.

B. Sculpture fine, the concentric
strongly elevated; lunule but
feebly defined; right valve not
overlapping the left bosener ye

valves flattened Callithaca

SUBGENUS PROTOTHACA §. S.
Protothaca (Protothaca) staminea Conrad

V[enus]. staminea Conrad, Jour. Acad. Nat. Sci. Philadel-
phia, Vol. 7, pt. 2, p. 250, pl. 19, fig. 15, 1837.

Not Cytherea staminea Conrad, 1839. [Referred to the
genus Antigona by recent authors. See Bull. Amer.
Paleo., Vol. 25, No. 94B, p. 61, 1941.]

Tapes staminea Conrad, [?] Dall, Proc. U. S. Nat. Mus.,
Vol. 1, p. 11, 1878. Later Tertiary of San Diego. —
[?] Orcutt, West Amer. Sci., Vol. 6, Whole No. 45,
p. 70, 1889. Pacific Beach, Tertiary. — Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 150, 1903. ‘Found in the
Pliocene at Pacific Beach and Russ School.” — Arnold,
U. S. G. S., Prof. Paper No. 47, p. 28, 1906. ‘‘Pacific
Beach,” ‘San Diego Formation.”

Paphia staminea Conrad, J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 3, pp. 173, 182, 1912. [Species at-
tributed to Carpenter.] ‘‘San Diego-Purisima,” lower
Pliocene. — I. S. Oldroyd, Stanford Univ. Publ. Univ.

Ser. Geol. Sci., Vol. 1, p. 157, 1924. “Pliocene” of
“San Diego.”’ — Waterfall, Univ. Calif. Publ. Bull.
Dept. Geol. Sci., Vol. 18, No. 3, opp. p. 78, 1929.

“San Diego Pliocene.”
Venerupis (Protothaca) staminea Conrad, Grant and Gale,
Mem. San Diego Soe. Nat. Hist., Vol. 1, p. 330, 1931.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Arnold’s record from San Diego Pliocene cited.

Protothaca staminea Conrad, Fitch, State Calif. Dept. Fish
Game, Mar. Fish. Branch, Fish Bull. No. 90, p. 66,
fig. 32, 1953. “Range: Aleutian Islands to Cape San
Lucas, Baja California.”

Type specimen. — Two syntype lots Nos. 55.3.14.40
and 65.5.20.123, British Museum (Natural History) (A.M.
Keen, Veliger, Vol. 8, No. 3, p. 169, 1966).

Type locality. — “Inhabits the coast of California,
with the above.” [That is, Venus nuttalli, ““Inhabits the
coast of California, Sta. Barbara, and Sta. Diego.” |

Range. — (cf.) middle Miocene; late Miocene to
Recent from the Aleutian Islands to Cape San Lucas,
Lower California, Mexico, from shore to 46 meters (25
fathoms).

Occurrence in San Diego Fm. — L.A.M. 305.

Original description. — Shell suboval, or suborbi-
cular, convex, with numerous crowded radiating striae,
and finer concentric lines, most distinct on the anterior
side; posterior extremity direct; ligament margin nearly
parallel with the base; colour variegated with yellowish
and brown, and with brown angular spots; cardinal teeth
compressed; sinus of pallial impression profound. Length,
one and a half inches. (Conrad.)

Remarks. — Fragments of the anterior end of a
valve are present in the collections of the Los Angeles
County Museum from near the Mexican boundary. The
largest fragment, 29 mm long, retains the radial ribbing
and lunular area. The shell characters agree well with
the corresponding sculpture on valves of Protothaca sta-
minea of the same size.

Two casts of a bivalve resembling this species,
collected by Charles Sternberg in the San Diego Formation,
are in the collections of the Academy. There is no infor-
mation as to the exact locality from which they came,
but the matrix, gray sandstone, is similar to that of other
species which were collected near and under the Mercy
Hospital foundation on Sixth Street in San Diego. The
outline, traces of radial ribbing and all observable charac-
ters are similar to those of Protothaca staminea. The
largest specimen is 65 mm long and 62 mm high.

One valve labelled as coming from Loe. 122 (LAM)
Pacific Beach, may have come from beds of Pleistocene
age.

This species has been recorded by several authors
as occurring in the Pliocene beds at San Diego. It also
is well known in beds of Pliocene, and Pleistocene age,
along the west coast of North America. It apparently
ranges from middle Miocene age but Loel and Corey did
not cite it in their list of Temblor species.

Protothaca staminea is represented by a number of
forms occurring in waters of the northeastern Pacific,
including those described as Venerupis petitii Deshayes,
1839, Tapes ruderata Deshayes, 1853, Tapes staminea var.
orbella Carpenter, 1864, and Protothaca staminea var.
spatiosa Dall, 1916. The species described as Tapes
laciniata by Carpenter, 1864, and its Pliocene relative
Paphia (Protothaca) staminea var. hannibali Howe, 1922,
are distinct from typical P. staminea. The longer pallial
sinus, extending more than one half the distance from
the posterior toward the anterior end, is a feature which
serves to separate the present species from P. grata Say,
a generally more southern species.

Protothaca_ (Novacallithaca)

euglypta Sowerby,

from Japan, is more elongate in outline and the margin
bears strong denticulations.

Protothaca kovatschensis Ilyina (952) described from
strata of Miocene age in Kamtschatka was compared by
its author with P. staminea.

Protothaca staminea occurs abundantly in shallow
water in bays and inlets often at depths of two or three
inches in coarse, sandy, muddy bottoms and on the open
coast in sand under cobbles and rocks. The ecology and
growth of this species has been discussed by Smith (953).

SUBGENUS CALLITHACA DALL

Callithaca Dall, Proc. U. S. Nat. Mus., Vol. 26, No. 1312,
p. 364, December 29, 1902.

Protocallithaca Nomura, Saito Ho-On Kai Mus. Res. Bull.,
No. 13, p. 10, August, 1937. “Genotype: Venus
adamsi Reeve, 1850.” Illustrated pl. 3, figs. 4a, 4b.
Japan, Recent. — See also Habe, Gen. Jap. Shells,
Pelecypoda, No. 2, p. 180, September, 1951.

Type species (by original designation). — “Type,
Tapes tenerrima Carpenter.”

Range. — Late Miocene to Recent, western North
America and Japan. Recent from the intertidal zone to
about 46 meters (25 fathoms).

Original description. — Sculpture delicate, uniform
over the disk and reticulate except in distorted individuals;
lunule feebly defined with no escutcheon; the dorsal
margin not overlapping in the right valve; inner margins
entire, otherwise as in Protothaca. (Dall.)

Remarks. — This subgenus was considered to be of
no taxonomic importance by Frizzell, 1935, and Grant
and Gale, 1931.

The differences between the type species of Proto-
thaca and Callithaca may be of only specific value, but
the fact that the right valve does not overlap the left
posteriorly, the faintly defined lunule, and the smooth
inner margins of the valves of Callithaca are distinct fea-
tures. For the present we retain Callithaca as a subgenus
of Protothaca.

Key To Species And Subspecies Of Callithaca

A. Posterior end elliptically curved;
height 70 to 75 percent
of the length : tenerrima
B. Posterior end broadly curved
(or subtruncated); height 75 to 80
percent of the length . (subspecies) alta
Protothaca (Callithaca) tenerrima Carpenter
Plate 51, Figures 1-3; Plate 52, Figures 13, 14

Tapes tenerrima Carpenter, Proc. Zool. Soc. London for
1856, p. 200, issued January 7, 1857.

Paphia tenerrima Carpenter, J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 3, pp. 173, 182, 1912. “San Diego-
Purisima.’’ Lower Pliocene. — Packard, Univ. Calif.
Publ. Zool., Vol. 14, No. 2, p. 272, pl. 22, figs. 1a, 1b,
1918. “Range. — Strait of Juan de Fuca, Washington,
to San Quentin Bay, Lower California (Dall).”—TI. S.
Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci.,

278

Vol. 1, p. 156, pl. 30, figs. la, 1b, 1924. Various
localities cited; range, from Pliocene to Recent.

Protothaca tenerrima Carpenter, Fitch, State Calif. Dept.
Fish Game, Mar. Fish. Branch, Fish Bull. No. 90, p. 65,
fig. 31, 1953. “Range: British Columbia to Magdalena
Bay, Baja California.”

Protothaca (Callithaca) tenerrima Carpenter, K.V.W. Pal-
mer, Geol. Soc. Amer., Mem. 76, p. 97, 1958. [Dis-
cussion of Carpenter’s species. Type specimen not
found. |

Type specimen. — Location unknown to the present
authors.

Type locality. — “‘Hab. Panama; legit Col. Jewett.
Mus. Gould.” [Carpenter later stated. “. . .Tapes tener-
rima, Cpr., P. Z. S. July 1856, which is a Californian and
not a Panamic species, as had been supposed from Col.
Jewett’s label”. (See Rept. Brit. Assoc. Adv. Sci. for
1863, p. 531, August, 1864.) ]

Range. — Late Miocene (“‘cf.”); early Pliocene to
Recent. Recent from Vancouver Island, British Columbia,
to Cape San Lucas, Lower California, Mexico; beach to
46 meters (25 fathoms). Often in sandy bays and estuaries
at depths of 10-16 inches beneath the surface (Fitch).

Occurrence in San Diego Fm. — C.A.S. 957, 1135,
1140, 1178, 1402, 28885, 28886. L.A.M. 104, 305,
305A, 305C. S.D. 21, 417. U.C.L.A. 294.

Original description. — T. t. tenerrima, albido-fusca,
obovali, compressa; marginibus aequaliter excurvatis; striu-
lis radiantibus creberrimis, antice et postice fortioribus, et
lirulis acutis concentricis, plus minusve distantibus, ele-
ganter ornata; lunula vix stria majore definita; intus, dent.
card. iii. radiantibus, quorum valva in altera ii. altera i.
bifidi sunt; sinu palii maximo, elongato, lateribus suberec-
tis, parum divergentibus, apice cicatr. ant. contiguo,
subrotundato; margine vix crenulato. Long. .94, lat. 1.13,
alt. .38. (Carpenter.)

Remarks. — Several specimens, in various states of
preservation, are present in the collections from the San
Diego Formation. One specimen retaining the anterior
portions of both valves came from Loc. 305A (LAM)
from near the Mexican boundary. A large left valve from
Loc. 305C (LAM) is 126 mm long and 92.5 mm high.
The shell characters of the various specimens all appear
identical with those of Recent Protothaca tenerrima.

Perfect specimens of P. tenerrima are easily separable
from other west American species of this genus by the
elongate, ovate, flattened shell which is sculptured with
fine sharp concentric lamellae.

A subspecies, Protothaca (Callithaca) tenerrima alta
Waterfall, described from strata of Pleistocene age in
Ventura Co. California, is comparatively higher in pro-
portion to the length.

Protothaca restorationensis Frizzell (955) described
from Pleistocene beds at Puget Sound, Washington, is
intermediate in outline between P. staminea and P.
tenerrima. The shell is thicker and the valves are more
inflated than the latter species. Protothaca restorationen-
sis occurs from Puget Sound to Halfmoon Bay, California.
A specimen collected by Mrs. Jack Copsey at Loc. 33901
(CAS), Tom’s Point, Bolinas Bay, California, agrees well
with paratypes (Nos. 5350, 5351) of Frizzell’s species in
the series of type specimens in the California Academy
of Sciences.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Protothaca (Callithaca) tenerrima alta Waterfall
Text-Figure 12

Paphia (Callithaca) tenerrima alta Waterfall, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 18, No. 3, pl.
6, fig. 1, April 6, 1929.

Type specimen. — No. 31418, Invertebrate Paleon-
tology Collection, University of California.
Type locality. — ‘Saugus, U. C. Loc. 7088, Hall

Canyon, two miles northeast of Ventura, California.”

Range. — Middle Pliocene to Pleistocene.
Occurrence in San Diego Fm. — L.A.M. 305C.

Text Fig. 12. Protothaca (Callithaca) tenerrima alta
Waterfall. Hypotype (Los Angeles County Museum), right
valve, from Loc. 305C (LAM), near the Mexican boundary,
southwestern San Diego County; Pliocene. Length
125 mm. (Drawn by Dorothy Ludlow.)

Original description. — Shell large, relatively thin,
oval; beaks strongly prosogyrous, small, situated about
one-sixth the distance from the anterior end; dorsal side
evenly convex, rising slightly above the beaks; ventral side
subtruncate; sculpture consists of more or less evenly
spaced, fine concentric ridges which are, in general, spaced
about 3 mm apart in the central part of the shell, between
which there are, in places, similar but finer lines and
faint incremental lines which become more prominent
toward the periphery; radial sculpture consists of fine
low ridges, less prominent than the concentric lines; and
most prominent between the latter; teeth in the left valve
(broken in type) three, sharp, the central one bifid; right
valve unknown; hinge long, narrow, no lunule or escutch-
eon; pallial sinus reaching to about one-third the distance
from the anterior end.

Dimensions. — Height, 96 mm, length 117 mm,
diameter of left valve 25 mm. (Waterfall.)

Remarks. — A right valve 125 mm long and 103
mm high, a left valve 125 mm long and one specimen
with both valves, are here assigned to Protothaca (Callitha-
ca) tenerrima alta. The right valve, relatively higher in
proportion to the length of typical P. (C.) tenerrima and

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

with a broadly rounded (nearly subtruncated) posterior
end, is typical of the subspecies. The left valve is less
typical but appears to be referable to this subspecies.
A smaller specimen from the same locality is 93 mm long,
71 mm high, the convexity (both valves together) 33 mm.
The posterior end of this fossil is more steeply sloping
than specimens of typical P. (C.) tenerrima of comparable
size.

The shell characters which serve to distinguish this
subspecies from the typical form are more apparent on
large adults than on juvenile specimens.

GENUS IRUSELLA N. GEN.

Irus of west American authors.
Not Jrus Oken, 1815, nor Jrus Schmidt, 1818.

Type species. — Venus lamellifera Conrad, 1837.

Range. — Aquitanian, early Miocene, to Recent.
Recent from low tide to about 65 meters (35 fathoms).

Description. — Shell small to moderate size (40
mm long), ovate, roundly truncated posteriorly, moderate-
ly convex; sculptured with elevated, slightly reflexed,
concentric lamellae which are separated by smooth inter-
spaces 3 to 4 mm wide, and on the early portions of the
valves, by fine radial striae; lunule small, ovate, crossed
by the concentric lamellae; ligament external, sunken be-
low edge of dorsal margin. Hinge plate narrow, four
teeth in each valve, the anterior one smallest, the left
middle and right middle and posterior ones with a slight
median groove; ventral margin finely denticulated; poster-
ior muscle impression the larger; pallial sinus extends for-
ward a little less than half the length of the shell, roundly
pointed at the end.

Remarks. — The west American species described
as Venus lamellifera by Conrad has been placed in the
genus Irus Oken (956) by some authors. Oken’s usage
of that generic name is not available because the publica-
tion in which it appeared was ruled invalid for purposes
of nomemcelature by the Internat. Comm. Zool. Nomencl.
in 1956, Opinion 417. Keen (957) called attention to this
ruling and suggested that Venus lamellifera be placed in
Notirus Finlay (958). The type species of that genus,
Venerupis reflexa Gray, is sculptured with numerous fine,
low, concentric lamellae and, on the specimens which we
have examined, there is almost no circumscribed lunule
and the early portion of the shell lacks radial striae.

Recently, Bowden and Heppell (Jour. Conch., Vol.
26, No. 4, p. 260, 1968) called attention to and accepted
the usage of Jrus Schmidt (Versuch. Conchyl. — Samml.,
p. 158, 1818) with the type by tautonomy, Donax_ irus
Linnaeus.

The new genus here proposed, /rusella, is similar to
Paphonotia Hertlein and Strong (959), but it differs from
that genus in the much thicker shell, coarser concentric
lamellae, the radial sculpture confined to the early portion
of the shell and the ventral margin of the interior denti-
culated rather than smooth. The species of this genus
live in holes in rocks or in empty shells or in holes which
it forms by burrowing in soft rocks. The shape is extreme-
ly variable.

Trusella lamellifera Conrad
Plate 50, Figure 11

279

V[enus]. lamellifera Conrad, Jour. Acad. Nat. Sci. Phila-
delphias VolS 7; Bt. 25 p. 2515 pl. 195 fis: 195 1837.

Petricola cordieri Deshayes, Rev. Zool., Soc. Cuvierienne,
Année 1839, p. 358 (December, 1839). ‘California,
dans les marnes calcaires, ou elle se creuse des trous
profonds.”’ — Deshayes, Mag. de Zool., Livr. 6, Moll.,
pl. 18, 3 figs., 1840.

Venerupis lamellifera Conrad, I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 160, pl. 39, fig.
8, 1924. Monterey to San Diego, California, Recent.

Trus lamellifer Conrad, Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 332, pl. 18, figs. 5a, 5b, 6a,
6b, 8, 1931. Pliocene to Recent. — Abbott, American
Seashells (D. Van Nostrand Co., Inc.: New York),
p. 412, pl. 31, fig. 3, 1954 (as Jrus lamellifera). Mon-
terey to San Diego, California.

Type specimen. — Location of type specimen un-
known to the present authors.

Type locality. — “Inhabits the coast of California,
with the preceding. Very rare; a single valve only was
found.” [The preceding species is “V. californiana. Sby.”
from “Inhabits the coast of California, in muddy marshes
near Sta. Diego.’’]

Range. — Late Miocene to Recent. Recent from
Shelter Cove, Humboldt Co., to San Diego, California
(960), from low tide to 65 meters (35 fathoms).

Occurrence in San Diego Fm. — U.C.L.A. 298.

Original description. — Shell suboval, compressed;
disks with about eight lamelliform concentric slightly re-
flected ribs, and very obscure radiating sulci; posterior
extremity widely truncated; colour white; pallal impres-
sion with a profound sinus. (Conrad.)

Remarks. — A single right valve, length 27.3 mm,
height, 24 mm, convexity, 12 mm, from Pliocene strata
at Pacific Beach, is present in the collections of the
University of California at Los Angeles. The umbonal
portion and the hinge are lacking and the concentric
lamellae are more irregularly spaced than typical forms
of this species. This form is well within the variation of
Trusella lamellifera resulting from its habit of boring
in soft rocks or nestling in pre-existing cavities.

A large left valve of this species from San Miguel
Island, California, in the Henry Hemphill collection in the
California Academy of Sciences, is 42.5 mm long.

A variety of this species of Miocene age, described
by Grant and Gale (961), was said to differ from typical
Trusella lamellifera in the more widely separated concentric
lamellae and more circular shape.

Petricola cordieri Deshayes, 1839, is a synonym of
Trusella lamellifera. Records of ““Venerupis” cordieri from
Port Alfred, South Africa, are referable to Venerupis
multicostata Turton (962).

GENUS PSEPHIDIA DALL

Psephis Carpenter, Rept. Brit. Assoc. Adv. Sci. for 1863,
pp. 536, 611, 640, August, 1864. Reprint in Smithson-
ian Misc. Coll., No. 252, pp. 22, 97, 126, 1872. — Car-
penter, Proc. Acad. Nat. Sci. Philadelphia, Vol. 17,
p. 56, April, 1865.

Not Psephis Guenée, 1854. Lepidoptera.

Psephidia Dall, Jour. Conch., Vol. 10, No. 8, p. 243,
October 1, 1902. New name for Psephis Carpenter,

280

1864, not Psephis Guenée, 1854. — Dall, Proc. U. S.
Nat. Mus., Vol. 26, No. 1312, p. 366, December 29,
1902. “‘Type: Psephis lordi Baird.”” — Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 336, 1931.
Type as indicated by Dall. — Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New
York), p. 313, 1961. “Type species by original desig-

nation, Psephis lordi Baird.”

Type species (subsequent designation for Psephis by
Carpenter, 1865). — “Exemplum typicum: Psephis Lordii
= Chione Lordii, Proc. Zool. Soc., 1863, p. 69.” Same
designated for Psephidia by Dall, 1902.

Range. — Middle Pliocene to Recent. Recent from
about 9 to 91 meters (5 to 50 fathoms).

Description. — Shell small, veneriform, polished,
with faint sculpture; beaks not prominent; valves inequil-
ateral, with a narrow, feebly defined lunule and no es-
cutcheon; inner margins not crenate; pallial sinus distinct,
angular; hinge with three delicate entire cardinals in
each valve, but no laterals; animal with the mantle edges
fused below, the siphons short, simple; an anterior open-
ing for the foot, which is not byssiferous.(Dall, 1902.)

Remarks. — Five species of Psephidia have been re-
corded from strata of Pliocene and Pleistocene age in Cali-
fornia and a like number have been recorded living in
west American waters between Unalaska, Alaska, to the
Gulf of California. Three of these are known to be
viviparous.

Key to Species of Psephidia

A. Valves smooth, with lines of

growth only . ovalis
B. Valves sculptured with
concentric ridges stephensae

Psephidia ovalis Dall
Plate 47, Figures 5, 9; Plate 51, Figures 8, 9

Psephidia ovalis Dall, Proc. U. S. Nat. Mus., Vol. 26, No.
16, fig. 4, December 29, 1902. — Dall, U. S. Nat.
Mus., Bull. 112, p. 44, 1921. Range: St. Paul Island,
Bering Sea, to San Diego, California. — I. S. Oldroyd,
Standford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1,
p. 161, pl. 34, fig. 4, 1924. [Same range as given by
Dall.] — J. Q. Burch (editor), Min. Conch. Club South.
California, No. 42, p. 16, fig. (p. 17), December, 1944.
Range as given by Dall. (See also Viola S. Bristol, No.
52, p. 35, 1945.) — Abbott, American Seashells (D.
Van Nostrand Co., Inc.: New York; Toronto; London),
p. 411, fig. 82c [not 82b=P. lordi], 1954. [Copy of
Dall’s illustration. ]

Psephidia lordi Baird variety ovalis Dall, Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 337, 1931.
Pliocene to Recent. — Faustman, Univ. Calif. Publ.
Geol. Sci., Vol. 41, No. 2, p. 121, 1964 (as Psephidia
lordi Baird subsp. ovalis). Rio Dell Formation; Elk
River Formation; Scotia Bluffs Sandstone; Merced For-
mation; Etchegoin Formation.

Type specimen. — No. 163089, United States Nation-
al Museum.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Type Locality. — “North side of Catalina Island,
California, in 16 fathoms gravel and sand; W. H. Dall.”

Range. — Middle Pliocene to Recent. Recent from
St. Paul Island, Bering Sea, to San Diego, California, 29
to 91 meters (16 to 50 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305C.

Original description. — Shell small, white, polished,
oval, subcompressed; surface with obsolete concentric
threads near the anterior base, but over most of the disk
smooth; beaks small and very low, at about the anterior
third of the length; lunule elongated, extremely narrow,
nearly as long as the anterior dorsal slope; escutcheon
linear or none; interior white, the pallial sinus moderate,
pointed; internal margin delicately straited; hinge well
developed, like that of P. lordi, with three entire card-
inals and no anterior lateral tooth. Length, 8.5; height,
6.5; diameter, 3.0 mm. (Dall.)

Remarks. — Two small valves and one larger one
(5.5 mm long) in the collection from near the Mexican
boundary are referred to Psephidia ovalis. These valves
are not as ovate as the original illustration of the type
specimen. However, considerable variation is observable
among individuals in a series of Recent specimens. Dr.
Myra Keen compared the valves from the San Diego
Formation with Recent specimens of P. ovalis in the
collection at Stanford University and considers the
fossil valves to be definitely referable to this species.

Some authors have considered this form to be a
subspecies of P. lordi Baird (963) but in many recent
works it is accorded specific status.

Psephidia stephensae n. sp.
Plate 44, Figures 21, 22, 24, 26

Description. — Shell small, rounded triangular, the
beaks slightly anterior of the center, lunule and escutch-
eon only slightly developed; exterior with well developed,
slightly irregular, concentric sculpture, the ridges rounded
in the early stage but flattened on the later stage of the
valves; hinge with three cardinal teeth, the central one the
larger and slightly grooved; interior smooth, margins with
two or three faint concentric grooves; muscle impressions
typical of the genus; ligamental area small. Length of holo-
type 3.0 mm, height 2.7 mm.

Type specimens. — Holotype, a right valve, and para-
types a right and a left valve (Los Angeles County Mus-
eum), from Loc. 305A (LAM), west side of next gully
east of Loc. 305 (LAM), at the same elevation; fossils
in float slump and consolidated boulders, silt and sand-
stone, and silt in place. San Diego Formation, Pliocene,
[Loc. 305 (LAM) is 2400 feet east and 1350 feet south
of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian].

Range. — Middle Pliocene to Recent. Recent from
off Santa Rosa Island, California, to San Hipolito Point,
Lower California, Mexico, also Guadalupe Island, and
Cedros Island, in 16 to 88 meters (9 to 48 fathoms).

Occurrence in San Diego Fm. — L.A.M. 319.

Remarks. — A number of specimens, mostly single
valves, of this species are in the collection of the Los
Angeles County Museum from near the Mexican bound-
ary.

Variation in proportion of length to height can be
observed in a series of specimens. Some are more highly

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

trigonal than others.

This new species resembles Psephidia cymata Dall
(964) but differs chiefly in lacking an anterior lateral
tooth in the left valve. Dall did not mention this feature
of the hinge in the original description of his species.
Woodring (1941), p. 95) mentioned the presence of
“a short anterior lateral lying close to the anterior
cardinal” on Dall’s species and A. M. Keen (written
comm.) noticed a similar tooth on a paratype of P.
cymata in the collection in Stanford University. The
presence of a left anterior lateral is a characteristic
feature of Transennella (separating it from Psephidia)
and on this basis Dall’s species should be assigned to
that genus.

Recent specimens reported under the name of
Psephidia cymata from off Guadalupe Island (Hanna
and Strong, Proc. Calif. Acad. Sci., Ser. 4, Vol. 19, No.
1, p. 6, 1930) and from off Cedros Island (Hertlein and
Strong, Zoologica, Vol. 33, pt. 4, p. 193, 1948), appear
to be identical with the new species described here.

A fossil cited as “Psephidia n. sp. ?” was reported
by Woodring (965) from strata of Pliocene age in San
Joaquin Valley. It resembles ‘‘Psephidia” cymata Dall
but is smaller, more trigonal, and lacks an anterior lat-
eral tooth. The shape is much more highly trigonal than
the new species from San Diego.

The shell of Psephidia salmonea Carpenter (966) is
generally more elongated and the concentric sculpture is
much finer and more closely spaced than that on P. step-
hensae n. sp.

This species is named for Mrs. Kate Stephens, for-
mer Curator of Marine Invertebrates, San Diego Society
of Natural History.

[Psephidia barbarensis Arnold]

Psephidia barbarensis Arnold, Smithsonian, Misc. Coll.
(Quarterly Issue), Vol. 50, Pt. 4, No. 1781, p. 440
(22), pl. 58, fig. 3, December 13, 1907. — Arnold, U. S.
Gas bulls No; S215 "ps! 32) pl: 12) fig) 3, 1907.
“Fernando formation, Bath-house Beach, Santa Bar-
bara,” ‘Fernando (Pliocene).”” — Waterfall, Univ.
Calif. Publ. Bull. Dept. Geol. Sci., Vol. 18, No. 3,
table opp. p. 78, 1929. “San Diego Pliocene.”

Type specimen: Holotype No. 165,238, United
States National Museum.

Type locality: “‘Bath-house Beach, Santa Barbara,
California.”

Range. —? Middle Pliocene (Waterfall), to late
Pliocene or early Pleistocene.

Occurrence in the San Diego Formation. — ‘San
Diego Pliocene” (Waterfall).

Remarks. — The only record of Psephidia barbar-
ensis from the San Diego Formation is that of Water-
fall. Dr. E. C. Allison and Mr. Joseph Peck, Jr., searched
for but failed to find the specimen or specimens in the
collections of the University of California upon which
Waterfall’s record was based. We have not noticed this
species in any of the collections which we have studied
from the San Diego Formation.

According to Arnold the diagnostic features of this
little venerid are, ‘“This species is higher and more trigonal

281

in outline, has a straighter anterior margin, and a less
conspicuous anterior tooth than P. lordi Baird, which
it resembles.”

Keen and Bentson (967) stated that Psephidia
barbarensis is probably identical with Venus rhysomia
Gabb (968), described from strata at Santa Berbara
California, but the type material of Gabb’s
was not detected by them.

>

species

GENUS TRANSENNELLA DALL

Transennella Dall, Proc. U. S. Nat. Mus., Vol. 6, p. 341,
1883 (issued January 4-9, 1884). Sole species, ‘Cytherea
(Transennella?) conradiana n. s.” — Dall, Proc. U. S.
Nat. Mus., Vol. 26, No. 1312, p. 348, 1902. “Type,
T. conradiana Dall.” p. 367, pl. 13, fig. 6 [not fig. 5
as stated on p. 411], 1902. — Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 6, p. 1240, October, 1903.
“Type T. conradiana Dall. Florida.’ — Hertlein and
Strong, Proc. Calif. Acad. Sci., Ser. 4, Vol. 23, No. 24
p. 376, 1939. Type by monotypy.

Type species (by monotypy). — Cytherea (1rei-
sennella?) conradiana Dall, 1884, p. 340. ‘‘Habitat. —
Rare at Cedar Keys, in mud between tides.” [Illustrated
by K. V. W. Palmer, Palaeontogr. Americana, Vol. 1, No.
5, p. 302 (94), pl. 47, (16), figs. 4, 8, 10, fig. 10 in text,
1927. Florida, Pleistocene and Recent. — Abbott, Amer-
ican Seashells (Van Nostrand Co., Inc., New York), p.
413, fig. 83c, 1954. “South half of Florida and the Ba-
hamas’’, Recent. |

Range. — Early Miocene to Recent. Recent in Atlan-
tic and Caribbean from Florida to the West Indies; in the
Pacific from Sitka, Alaska, to Chile, from the inter-
tidal zone to about 91 meters (50 fathoms).

Description. Shell small, trigonal, with lively colo-
ration; smooth and polished or concentrically striate;
hinge with three cardinals in each valve, the middle left
cardinal bifid; an elongated anterior lateral in the left
valve, received in a sulcus in the right valve; lunule
defined by an incised line, escutcheon not defined; nymphs
without rugosities; pallial sinus angular, free below, ob-
liquely ascending; internal margins of the valves sharply
tangentially grooved with numerous sulci. (Dall, 1903.)

Remarks. — The presence of an anterior lateral
tooth in the left valve serves to separate Transennella
from Psephidia. The presence of strong oblique grooves
on the margins of the valves is generally considered to be
a characteristic feature of Transennella.

Species referred to this genus have been reported
only from the Atlantic and Pacific coasts of the Amer-
icas. The Atlantic species, typical of the genus as men-
tioned by several authors, possess a deeper pallial sinus,
the oblique grooving on the interior ventral margin is
stronger and so far as known, they are not viviparous.

In California, Transennella joaquinensis Anderson
and Martin was described from Temblor beds of middle
Miocene age, T. californica Arnold was described from
strata of Pliocene age, and T. tantilla Gould has been re-
ported with doubt from beds of late Miocene age and de-
finitely from late Pliocene to Recent. Transennella her-
viderana Spieker was described from beds of Miocene
age in Peru, and T. galapagana Hertlein and Strong was

282

recorded from a raised beach deposit of Pleistocene
age, also Recent, in the Galapagos Islands. Five species
referred to Transennella live in west American waters
in the region between Sitka, Alaska, and Chile. The spec-
ies described as ‘‘Psephidia” cymata by Dall may be re-
ferable to Transennella.

Transennella tantilla Gould
Plate 44, Figures 20, 23, 25, 27

Venus tantillus Gould, Boston Jour. Nat. Hist., Vol. 6,
p. 406, pl. 15, fig. 10, October, 1853.

Transennella tantilla Gould, Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 338, pl. 15, figs. 8a,
8b, 1931. Pleistocene and Recent.

Type specimen. — “Half figured holotype” No.
169391, Museum of Comparative Zoology, Harvard Univ-
ersity (Johnson, U.S. Nat. Mus., Bull, 239, p. 156, 1964).

Type locality. —“‘Inhabits Santa Barbara. Col. Jew-
ett.”

Range. — ?Middle Miocene; middle Pliocene to Re-
cent. Recent from Sitka Harbor, Alaska, to Lat. 27° S.,
Lower California, Mexico, littoral zone to 36.5 meters
(20 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305A, 309,
318. U.C.L.A. 1386.

Original description. — Shell quite small, rather
solid, ovate-trigonal, inequilateral; beaks acute, surface
smooth or faintly waved with distant concentric furrows;
the dorsal margins are nearly straight, and meet at the
apex in a right angle, but the posterior side is a foufth
longer than the anterior; the anterior basal angle is well
rounded, while the posterior is acute; basal margin gently
curved. Color white, but the posterior third is stained
deep slaty blue outside and in, the line of demarcation
being quite abrupt and well defined; there is also a pencil
of the same color inside, running from the beak to the
anterior cicatrix; the rest of the interior is cream colored.
(Gould.)

Length one fourth of an inch; height one fifth of
an inch. (Gould.)

Remarks. — A series of specimens of this species
varying in size from 2 to 7 mm in length are in the coll-
ections from San Diego and from near the Mexican bound-
ary. The largest one is a left valve 7 mm long and 6 mm
high. Large Recent specimens attain a length of 8 mm.

These specimens agree with Recent shells in shape,
sculpture, and hinge. There are three cardinal teeth in
each valve and in the left valve there is an anterior lat-
eral tooth. A lanceolate lunule below the beaks is bounded
by a faintly incised line. The outline of the pallial sinus
on the fossils is similar to that on Recent specimens,
short, rounded at the end and directed toward the anter-
ior impression. The interior ventral margin is grooved.

“Transennella cf. T. tantilla (Gould) (969) was
recorded from the middle part of the Altamira Shale
member of the Monterey Shale probably of middle
Miocene age in Los Angeles Co. Specimens, possibly T.
tantilla, were found in Pliocene strata in the Santa
Maria district. According to Woodring (970) those fossils
are smaller and have a thinner shell than Recent specimens
of T. tantilla.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Transennella tantilla was recorded by Martin (971)
from the Merced Formation of late Pliocene age, near
San Francisco, California. In a later paper Martin (972)
cited it only from the “Upper Merced” of Pleistocene
age. It also has been recorded from strata of late Pliocene
age in the Los Angeles area.

A small venerid in the upper Etchegoin and in the
San Joaquin Formation in the San Joaquin Valley,
was referred by Stewart (973) to “Transennella cf. T.
tantilla (Gould.)” He suggested that Transennella calif-
ornica Arnold (974) is probably identical with T. tan-
tilla. Woodring (1950, p. 90), however, stated that the
type specimen of T. californica has a more inflated umbo
than that of the Recent shalls of T. tantilla.

Hansen (975) discussed the brooding habits and
other features of living Transennella tantilla.

FAMILY PETRICOLIDAE D’ORBIGNY (976)

Shell elongate to subglobose, variable in shape on
account of the habit of boring in clay or soft rock, or
nestling in holes in rock or in other shells; gaping at both
ends; hinge narrow, with two or three cardinal teeth in
each valve, of which one or more may be bifid, the pos-
terior cardinal tooth generally small; ligament external,
attached to a coarse posterior nymph; sculpture con-
sisting of radial ribs and fine concentric lamellae which
may be nearly obsolete; pallial sinus usually extending to
the middle of the valve. (Adapted from Grant and Gale,
Mem. San Diego Soe. Nat. Hist., Vol. 1, p. 354, 1931 and
Olsson, Mollusks of the Tropical Eastern Pacific Paleo.
Res. Inst.: Ithaca, New York, p. 314, 1961.)

Range. — Cretaceous to Recent.

Remarks. — This family is represented in the
Cenozoic of western North America by one genus and
three subgenera.

GENUS PETRICOLA LAMARCK

Petricola Lamarck, Syst. Anim. s. Vert., p. 121, 1801.
Species cited: ‘‘Petricola sulcata. n. Venus lithophaga.
Retz. In Act. Acad. Taurin. vol. 3, p. 11.” “Petricola
costata, n. Venus lapicida, Chemn. Conch. 10, p. 356,
t. 172, f. 1664, 1665. An Donax irus. Linn.” ‘‘Pet-
ricola striata. n.”” — Gardner, U. S. G. S., Prof. Paper
199-A, p. 116, 1943 (issued January, 1944). Type as
designated by Schmidt.

Type species (by subsequent designation, Schmidt,
Versuch Conchyl.-Samml., pp. 55, 176, 1818). — “Type
Venus lapicida. X. Fig. 1664, 1665.” [Chemnitz, Syst.
Conchyl. Cab., Bd. 10, p. 356, Tab. 172, figs. 1664,
1665, 1788. In ‘“Corallsteinen gefunden, dergleichen
einige Schiffer bey den Westindischen Zuckerinsuln als
Ballast im untersten Schifsraum eingeladen hatten”’. IIl-
ustrated by Warmke and Abbott, Caribbean Shells (Liv-
ingston Publ. Co.: Narberth, Pennsylvania), p. 191, pl. 44,
fig. e, 1961 (as Petricola lapicida Gmelin). |

Range. — Eocene (Keen); Recent, widely distributed
in temperate and tropical waters, from the intertidal zone
to 82 meters (45 fathoms).

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Description.—Shell thin, oval or elongate, often
irregular, gaping. Umbones anterior but not terminal.
Lunule ill defined. Sculpture dominantly radial and
in the genotype divaricate or zigzag. Inner margins smooth.
Ligament external, attached to nymphs. Armature of
right valve usually consisting of two cardinals, the post-
erior of which is grooved or bifid; third rudimentary
cardinal rarely present; left valve furnished either with
three divergent cardinals (the middle one bifid, the re-
maining two simple) or with two divergent cardinals (a
simple posterior and a bifid anterior); laterals absent
in the normal adult. Pallial sinus narrow, as a rule, and
ascending, with considerable variation in depth. (Gardner,
1948.)

This is a nestling or burrowing genus, which ex-
hibits the variability of dwellers in such a habitat. (Gard-
ner, 1948.)

Remarks. — One species of Petricola was described
from strata of late Miocene age in Contra Costa Co. and
two species have been reported from beds of Pliocene
age in southern California. One species is known to occur
in the San Diego Formation. About a dozen species and
varieties of this genus have been described from west
American waters in the region between California and
northern Peru. About 25 species, widely distributed, are
now living in temperate and tropical seas.

Warmke and Abbott mentioned that the divaricate
pattern on the exterior of the type species, Petricola
lacipida, is only a calcareous coating on the surface of
the shell and is not sculpture.

SUBGENUS RUPELLARIA FLEURIAU DE BELLEVUE

Rupellaria Fleuriau de Bellevue, Jour. Phys., Vol. 54, p.
347. Species cited: ‘“Repullaire stri¢ée” and ‘‘Rupell-
aire reticulée” ‘Venus lithophaga. Retz.” — Gardner,
U.S.G.S., Prof. Paper 199-A, p. 116, 1943 [ Jan-
uary, 1944]. “Type by elimination: Venus litho-
Phaga Retzius.”

Type species (designated by Dall, Trans. Wagner Free

Inst. Sci., Vol. 3, Pt. 5, p. 1058, 1900). — “Type P. lith-

ophaga (Retzius).”” [Mem. Acad. R. Sci. Turin, Vol. 3,

Mém des Corresp., pp. 11, 14, figs. 1, 2, 1786. Illustrated

by Bucquoy, Dautzenberg, and Dollfus, Moll. Mar. Rouss-

illion, Vol. 2, Fase. 9 (Pelecypoda, Fase. 22), p. 445,

pl. 67, figs. 20-25; 26-28 (var. striata), 1893. For

synonymy and discussion of this species see Lamy,

Jour. de Conchyl., Vol. 67, No. 4, pp. 323-328, 1923,

Mediterranean, Adriatic, and Atlantic from Strait of

Gibralter to England. ]

Range. — Eocene to Recent

Description. — Shell short, inflated anteriorly, more
compressed and attenuated posteriorly; radial sculpture
usually present over entire shell but coarser anteriorly;
pallial sinus broadly rounded at the end.

Remarks. — West American species which generally
have been referred to Petricola s. s. are referable to the

subgenus Rupellaria as mentioned by Keen. (977).

Petricola (Rupellaria) carditoides Conrad
Plate 44, Figures 15, 16

Sfaxicava]. carditoides Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 255, pl. 20, fig. 8, 1837.

283

S[axicava] . californica Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 256, pl. 20, fig. 9, 1837.
“Inhabits California near Sta. Barbara and Sta. Diego.”

Petricola carditoides Conrad, Packard, Univ. Calif. Publ.
Zool., Vol. 14, No. 2, p. 274, pl. 20, figs. 6a, 6b, 1918.
San Francisco Bay region, from between tides to a
depth of 45 fathoms. — I. S. Oldroyd, Publ. Puget
Sound Biol. Sta., Vol. 4, p. 50, pl. 42, figs. 6a, 6b,
1924. [Illustrations same as those of Packard.] San
Juan Island, Washington. — I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci. Vol. 1, p. 163, pl.
34, figs. 6a, 6b, 1924. [Illustrations same as those of
Packard.] ‘Bolinas”, California. Range: Vancouver
Island to Lower California. — Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 355, pl. 13,
figs. 14a, 14b, 1931, various localities, Pliocene to
Recent.

Type specimen. — Location of type specimen un-
known to the present authors.

Type locality. — “Inhabits California near Sta.
Barbara, where a single valve only was collected.”

Range. — Pliocene to Recent. Recent from Van-
couver Island, British Columbia to Scammon’s Lagoon,
Lower California, Mexico, from the littoral zone to 82
meters (45 fathoms).

Occurrence in San Diego Fm. — L.A.M. 107, 305.
U.C.L.A. 294.

Original description. — Shell oblong - oval; disks
with minute radiating lines; ligament margin straight,
parallel with the basal margin; posterior extremity direct;
cardinal teeth prominent. Length, an inch and a half
(Conrad.)

Remarks. — An elongate left valve of this species in
the collection of the University of California at Los
Angeles, is 30 mm long, and 15.7 mm high, convexity,
7.8 mm. Much of the sculpture on the exterior is
eroded but fine radial threads are visible on the anterior
portion of this specimen. It agrees in every way with
specimens of Recent Petricola carditoides.

A few poorly preserved specimens from Loc. 107
(LAM) are referable to P. carditoides and a fragment of a
right valve from Loc. 305 (LAM), from near the Mexican
boundary is probably referable to this species.

The shape of the shell of Petricola carditoides is
exceedingly variable, from elongate to rounded in out-
line, as a result of its habitat in holes in rocks, or in
other shells. The sculpture of the exterior is often almost
obliterated on some fossils. Four varietal forms of this
species were cited by Lamy (978).

Petricola pedroana Conrad (979), originally des-
cribed from beds of Pleistocene age at San Pedro, Calif-
ornia, is now generally placed in the synonymy of P.
carditoides.

Petricola lucasana Hertlein and Strong (980) des-
cribed from ‘‘Cape San Lucas, Lower California, Mexico’,
is a similar species but differs in the slightly coarser radial
riblets and in the different coloration of the shell. The
interior of the tropical form is blackish-brown and the ex-
terior dark orange-brown in comparison to the nearly
white shell of P. carditoides.

Petricola buwaldi Clark (981), described from late
Miocene strata in central western California, is allied to
P. carditoides and P. lucasana but possesses much coarser
radial riblets. Two species, comparable to P. carditoides

284

and P. buwaldi, respectively, were reported by Woodring
as occurring in strata of Pliocene age in the Santa Maria
region.

Yonge (982) gave an excellent discussion of the
occurrence and habits of Recent Petricola carditoides. He
concluded that this species usually settles in some pre-
existing cavity which, by mechanical means, the animal
enlarges to exactly fit the valves when open. The siphons
extend into the water.

SUPERFAMILY TELLINACEA OKEN (983)

A discussion of the structure and adaptations of the
Tellinacea has been published by Yonge (984).

FAMILY TELLINIDAE OKEN

Shell rounded anteriorly, more or less rostrate,
obliquely truncated and gaping posteriorly; valves slightly
unequal, compressed, margins usually smooth, beaks small,
sculpture usually concentric; anterior adductor impression
sometimes the larger; resilium subexternal; hinge plate
with small cardinals and with or without laterals; pallial

sinus usually long, sometimes discrepant on the two valves.

Jurassic (985) to Recent.

This family is represented in the San Diego For-
mation by three genera. Dall’s (986) useful synopsis of
the Recent west American species has been supplemented
by a compilation of the Recent species by Salisbury (987).
Many of the tropical and subtropical west American
species have been discussed by Hertlein and Strong
(988), Keen (989), and Olsson (990). Papers by Boss
(991) deal with the subfamily Tellinae in the western
Atlantic.

Key to Genera of Tellinidae

A. Hinge usually with lateral teeth;
exterior often shiny . Tellina
B. Hinge lacking lateral teeth; exterior often dull

a. Elongate to subtrigonal;
posterior end produced
and narrowed; moderately
COMPressedin e= aay wae ane ae

aa. Suborbicular to subtrigonal;
subequilateral; broad median
depression in right valve; strong
siphonal fold; moderately
inflated . erat

Macoma

Florimetis

GENUS TELLINA LINNAEUS

Tellina Linnaeus, Syst. Nat., ed. 10, p. 674, 1758. Tel-
lina radiata Linnaeus included among species cited. —
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

1, p. 357, 1931. Type as designated by Children,
Tellina radiata Linnaeus. — Gardner, U. S. G. S., Prof.
Paper 199-A, p. 94, 1943 [January, 1944]. Type as
designated by Schmidt, Tellina radiata Linnaeus.

Type species (designated by Schmidt, Versuch
Conchylien-Sammlung, pp. 51, 177, 1818). — “Typ.
Tellina radiata.” Same species also cited by Children,
Quart. Jour. Sci. Lit. Arts, Vol. 14, p. 306, pl. 5, fig.
46, 1823. [Tellina radiata Linnaeus, Syst. Nat., ed. 10, p.
675, 1758. ‘Habitat in Oceano Europaeo.” Illustrated
by Reeve, Conch. Icon., Vol. 17, Tellina, sp. 8, pl. 3, figs.
8a, 8b, 1866. ‘‘Hab. West Indies.” — Boss, Johnsonia,
Vol. 4, No. 45, p. 235, pl. 129, figs. 1-4; pl. 130, fig. 1,
1966. Florida to the Guianas, South America. — Afshar,
Geol. Soc. Amer., Mem. 119, p. 24, pl. 1, figs. 1-5, 1969.
See discussion of this species by Dodge, Bull. Amer.
Mus. Nat. Hist., Vol. 100, Art. 1, p. 45, 1952. ]

Range. — Early Cretaceous to Recent. Recent from
the intertidal zone to 1170 meters (640 fathoms).

Description. — Shell elongately oval to ovately trig-
onal; compressed, often rostrate or twisted posteriorly;
beaks low; porcelaneous; surface smooth or chiefly con-
centrically sculptured; ligament external, opisthodetic;
hinge with small cardinals and usually two laterals in each
valve; pallial sinus well developed, often partly confluent
with the pallial line.

Key to Subgenera of Tellina
A. Shell with course concentric sculpture

a. Two lateral laminae in
both left and right

valve . se Tellinella
aa. One or both lateral

laminae lacking or obsolete

in left valve Peronidia

B. Shell with fine concentric sculp-
ture or smooth.

a. Two lateral laminae in left
and right valve
aa. One or both lateral laminae
lacking or obsolete in left valve.

Tellina s. s. (992)

b. Valve with internal raised
radial ridge behind anterior
muscle impression . . .

bb. Valves lacking internal raise
radial ridge behind anterior
muscle depression.

Oudardia (993)

c. Pallial sinus confluent
with pallial line for
nearly entire

Jenethi ere rien mn . Moerella
cc. Pallial sinus only partly

confluent with pallial

line ei oy Cadella

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

SUBGENUS TELLINELLA MORCH

Tellinella Gray, Morch, Cat. Conch. Yoldi, Fas., 2, p. 13,
1853. Species cited include T. antoni Phillippi, T.
interrupta Solander, T. pulchella Lamarck, T. ros-
trata Linnaeus, T. virgata Linnaeus, and several others.
— Hertlein and Strong, Zoologica, Vol. 34, Pt. 2, p.
64, August 10, 1949. Type as designated by Stoliczka.

Type species (designated by Stoliczka, Mem. Geol.
Surv. India, Paleont. Indica, Ser. 6, Cretaceous Fauna of
South India, Vol. 3, pp. XVII, 116, 1871. — Tellina
virgata Linnaeus [Syst. Nat., ed. 10, p. 674, 1758.
“Habitat in O. Indico.” Illustrated by Hanley, Thes.
Conch., Vol. 1, p. 228, pl. 63, fig. 212, 1846. Indian
Ocean. — Afshar, Geol. Soc. Amer., Mem. 119, p. 25, pl.
2, figs. 1-5, 1969. ]

Range. — Cretaceous to Recent.

Description. — Shell with strongly rostrate pos-
terior end and concentric sculpture consisting of sharp,
elevated lamellae.

Remarks. — This subgenus is represented by several
species in the Tertiary strata of California. At the pre-
sent time only two species occur off California, and two
occur in tropical and subtropical west American waters.
Other Recent species occur in warm Atlantic and Indo-
Pacific waters.

Fleming (994) placed Maoritellina Finlay in the
synonymy of Tellinella.

Tellina (Tellinella) idae Dall
Plate 53, Figures 6, 11

Tellina idae Dall, Proc. U.S. Nat. Mus., Vol. 14, No. 849,
p. 183, pl. 6, fig. 3; pl. 7,figs. 1, 4, July 24, 1891. Long
Beach and Catalina Island, California, Recent. Also
“Fossil in the Miocene of San Diego, California.” —
Williamson, Proc. U.S. Nat. Mus., Vol. 15, No. 898,
p. 185, 1892. Dall’s record of San Diego occurrence
cited. — Cooper, Calif. State Min. Bur., Bull. No. 4,
p. 32, 1894. ‘“‘Mioc.? — San Diego, Dall.’ — LS.
Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 164, pl. 14, fig. 4, 1924. [Reproduction of
Dall’s (1891) pl. 6, fig. 3] — Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 358, pl. 20, fig.
12 (middle Pliocene over the Newhall railroad tunnel,
Los Angeles Co.), 14a, 14b (Upper San Pedro of Santa
Monica), 1931. Dall’s record, “Miocene” at San Diego
cited. — Hertlein, Stanford Univ. Bull., Ser. 5, No. 78,
p. 84, 1929. “San Diego Pliocene”. — Abbott, Ameri-
can Seashells (D. Van Nostrand: New York), p. 422,
figs. 28h, 87a, 87b, 1954. Santa Monica to Newport
Bay, California.

Type specimen. — No. 120098, United States
National Museum.

Type locality. — ‘“‘Habitat:
California.”

Range. — Middle Miocene (Temblor Formation) to
Recent. Recent from Santa Barbara Islands to San Pedro
and Long Beach, California, in 37 to 91 meters (25 to 50
fathoms).

Occurrence in San Diego Fm. — C.A.S. 1401.

Long Beach, San Pedro

285

L.A.M. 107, 305, 305A, 318, 319. S.D. 27, 29. U.C.L.A.
2359.

Original description. — Shell ovate - triangular, mod-
erately elongate, white, compressed; exterior of the right
valve slightly flatter, and with more prominent sculpture
than the left valve; beaks small, pointed, prominent, lat-
erally compressed, adjacent to each other; anterior part
of the shell slightly longer than the part posterior to the
beaks, evenly and regularly oval, the dorsal and basal
curves almost identical; posterior dorsal slope steeper,
rectilinear, obliquely truncate at its termination, the basal
curve (behind the perpendicular from the beaks) similar to
its anterior part as far as the flexure, which is narrow but
well marked, its basal end moderately incurved; behind,
it rises to a strong ridge the end of which forms a rostral
projection, behind which, in the right valve, is a deeply im-
pressed line a little in advance of the posterior dorsal mar-
gin, which is strongly compressed; on the left valve there
are two lines with a narrow impressed area between them,
above which the dorsal margin is swollen; in front of the
beaks is a narrow, acute, deeply excavated, short lunule;
behind the beaks is a large, narrow, still more excavated
escutcheon, most of which is excavated from the left
valve, which falls short of the right valve a little; the
ligament is sunken in and about half as long as the es-
cutcheon; it is quite invisible on a lateral view of the
shell; the left valve is regularly, sharply, closely, con-
centrically grooved, and both are obsoletely, finely, rad-
iately striate; the margin between the impressed area
of the left valve and the escutcheon is more finely
grooved than the rest and has a (somewhat irregularly)
denticulate dorsal edge; the right valve has the concentric
sculpture more distant and, ventrally, shows distinctly
elevated narrow lines with wider interspaces regularly dis-
posed, and also bears denticulations on its posterior dor-
sal margin; the umbones are nearly smooth; the shell gapes
but little, chiefly at the end of the rostrum; internally the
surface of the valves is smooth, the muscular and pallial
impressions are brilliantly polished; besides the usual
marks, in the specimen under examination there are, near
the posterior ventral angle of the pallial sinus, two small
circular impressions and some obscure and irregular mark-
ings at the entrance of the sinus, all due, doubtless, to
attachments of the mantle and probably inconstant or
variable in different individuals; the anterior part of the
pallial sinus nearly reaches the scar of the anterior add-
uctor, and nearly the whole of the basal part is coincident
with the line of the basal attachment of the mantle; the
hinge plate is broad and subtriangular, quite strong, bear-
ing one prominent grooved tooth between two channels;
behind the posterior channel, in the left valve, is a much
narrower, obscure, and little - raised tooth; the corres-
ponding second tooth in the right valve is anterior and
similarly obscure; the left valve is destitute of lateral teeth,
but in the right valve there is a short, strong, elevated, sub-
triangular; anterior lateral close to the anterior cardinal,
and a more distant and feeble posterior lateral over the
posterior adductor scar. Altitude of shell, 28.5; max-
imum longitude, 48; diameter, 8.5 millimeters, of which
5.0 millimeters is comprised in the left valve. (Dall.)

Remarks. — This species is represented in the pre-
sent collections by three nearly complete single valves and
by a number of small ones and fragments of valves. The
largest is a left valve from Loc. 305A (LAM), near the

286

Mexican boundary, 65.8 mm long, height (incomplete)
38.4 mm. A right valve, complete except for the ex-
treme posterior end, is 57 mm long, 33 mm high, and
convexity 6 mm. An impression of the larger portion
of a right valve from Loe. 1401 (CAS), from the south
slope of Mount Soledad, is 58 mm long (incomplete)
and 34.6 mm high.

The shell of this species is characterized by the
strongly rostrate posterior end and the well-developed,
raised, sharp, concentric sculpture. These concentric
threads are spaced a little less than 1 mm apart on the
medial portion of an adult right valve. Burch (995)
pointed out that young specimens of this species are
equilateral and triangular in shape with coarser sculpture
than on adults.

Tellina nevadensis Anderson and Martin (996) was
placed in the synonymy of T. idae by Grant and Gale.
The specimens in the type lot of T. nevadensis are large, a
paratype is 72 mm long. The type specimens are higher in
proportion to the length in comparison to specimens of
T. idae. Perhaps differences in details of the two are a re-
sult of size and preservation.

Tellina idae was recorded occurring in Temblor beds
of middle Miocene age by Loel and Corey, and by Stew-
art (997). The latter author cited “‘Tellina cf. T. idae
Dall” from the Temblor Formation and a species under
this same caption was listed by Woodring (998) from the
middle part of the Altamira Shale member in Palos Verdes
Hills, near San Pedro, California, in beds probably of mid-
dle Miocene age, and later (1950, p. 98) he cited it from
the Cebada Member of the Careaga Sandstone (Pliocene).
Moore (999) recently reported ‘‘Tellina aff. T.’ idae
Dall” from the Astoria Formation of middle Miocene
age in Oregon.

A similar species is Tellina tenuilineata Clark (1000)
which was described from near Walnut Creek, California, in
beds believed to be of Oligocene age.

Tellina englishi Clark (1001) described from beds of
late Miocene age is another similar species. Judging
from casts of the type specimen, the shell is more elong-
ated than that of T. idae. However, it may fall within the
variation of the Recent species as suggested by Grant and
Gale.

That Tellina idae may be recorded under more than
one name in the literature referring to the fauna of Mio-
cene strata appears quite possible, for Loel and Corey
(1002) cited T. idae, T. tenuilineata and T. tenuistriata
Davis (1003), all from the ““Temblor Horizon.”

Tellina idae has been recorded from several localities
from beds of Pliocene or Pleistocene age in southern Cali-
fornia; at San Quintin, Lower California; and by Durham
from beds of late Pliocene age in the Gulf of California.

SUBGENUS CADELLA DALL,
BARTSCH, AND REHDER

Cadella Dall, Bartsch, and Rehder, Bernice P. Bishop
Mus., Bull. 153, p. 196, July 25, 1938. “‘Type:
Tellina lechiogramma Melville.” — Habe, Gen. Jap.
Shells, Pelecypoda, No. 3, p. 212, 1952. “Type
species: Tellina lachiogramma Melville (original designa-
tion.)”

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Type species (by original designation). — ‘‘Tellina
lechiogramma Melville” [Tellina (Maera) lechriogramma
Melville, Mem. Proc. Manchester Lit. Philos. Soc., Ser. 4,
Vol. 7, No. 1, p. 65, pl. 1, fig. 22, 1893. “Hab. Bombay
(Abercrombie).’’ India. — Afshar, Geol. Soc. Amer., Mem.
119, p. 33, pl. 8, figs. 6-10, 1969. “Karachi, Pakistan.” ]

Range. — Late Miocene to Recent. Recent from
northern Lower California to Japan, India, and South
Africa.

Original description. — Shell small, broadly ovate to
donaciform, rather inflated, the valves comparatively
thick, white or grayish or tinged with rose. The umbones
are located a third to a fourth of the entire length from
the posterior end, from which the posterior margin may
descend rather sharply to an obtuse, postero-ventral
angle, or the posterior end may be somewhat longer and
rounded; anterior to the umbones is a long slender de-
pressed lunule. The sculpture consists of fine, closely
concentric ridges, which flatten out anteriorly so that the
sculpture there appears to consist of fine, evenly separated
grooves. Ligament rather short, situated in a broadly
lanceolate escutcheon. The hinge is typically tellinid, the
left anterior and right posterior cardinal teeth being
stout and triangular, with or without a slight groove; the
right anterior cardinal is usually rather well developed and
lamellar, while the left posterior cardinal is short and rath-
er thin; the laterals in the right valve are well developed,
while those in the left valve are fused with the margin.
Interior white or suffused with pink; muscle scars suborbi-
cular, the posterior one slightly smaller than the anterior
one. Pallial sinus rather large and broad, slightly ascending,
the basal margin only partly fused with the pallial line.
(Dall, Bartsch, and Rehder.)

For the present Cadella might be placed near
Moerella, which differs not only in shape and sculpture,
but also in having a larger sinus, which is almost com-
pletely fused ventrally with the pallial line, and a larger
right posterior lateral which is more closely approxi-
mated to the cardinal teeth than in Cadella. (Dall, Bartsch,
and Rehder.)

Remarks: Dall, Bartsch, and Rehder pointed out
that Cadella differs from Semelangulus Iredale (1004)
in possessing an external ligament.

Cadeila includes several small ovate species reported
only from the Pacifie and Indian Ocean. It is reported
from late Miocene to Recent in California, Pliocene to
Recent in Japan, and Recent in Hawaii, India, and South
Africa.

Tellina (Cadella) salmonea Carpenter
Plate 53, Figures 2, 3, 4, 8, 16

Maera salmonea Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, pp. 627, 639, issued August, 1864. Reprint
in Smithsonian Mise. Coll., No. 252, pp. 113, 125,
1872. — Carpenter, Ann. Mag. Nat. Hist., Ser. 3, Vol.
14, p. 423, December, 1864. Reprint in Smithsonian
Mise. Coll., No. 252, p. 235, 1872. “Hab. San Francisco
(Pac. Rail. E.E.); Neeah Bay (Swan), plentiful; Monte-
rey, 20 fathoms (Cooper).”’

Tellina (Moerella) salmonea Carpenter, Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 157, pl. 13, fig. 7, 1903.
“Pleistocene. — San Pedro (Arnold).” ‘“‘Living. — Van-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

couver to Monterey (Carpenter). — K.V.W. Palmer.
Geol. Soc. Amer., Mem. 76, p. 105, pl.13, figs. 17-19,
1958. Aleutian Islands, Alaska, to San Pedro, California.
Also Pleistocene.

Tellina salmonea Carpenter, Packard, Univ. Calif. Publ.
Zool, Vol. 14, No. 2, p. 276, pl. 25, figs. 3a, 3b; pl. 46
(map), 1918. Within San Francisco Bay and west of
the Golden Gate, in 614 to 17 fathoms. — I.S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
165, pl. 44, figs. 3a, 3b, 1924. (Under subgenus
Moerella) {Same figures as given by Packard, 1918.]
“Aleutian Islands to San Pedro, California.” Recent.

Type locality. — Indicated as from “Neighbourhood
of S. Francisco’’; “‘Vancouver Island, Straits of S. Juan de
Fuca, and adjoining Washington Territory”’; ““Neighbour-
hood of Monterey” (Carpenter, August, 1864). “Recent.
Neah Bay, Washington, Vancouver Island region (type)”
(K.V.W. Palmer).

Range. — Late Miocene (Cierbo Formation) to
Recent. Recent from the Aleutian Island, Alaska, to South
Coronado Island, Lower California, Mexico, usually on a
sand bottom, from the intertidal zone to 154 meters (84
fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A,
319.

Original description. — Small, subquadrate, glossy,
salmon-tinted. Beach-20 fm. (Carpenter, August, 1864.)

Supplementary description. — M. testa parva, solida
compacta, subquadrata; laevi, nitente, epidermide tenui
cinera induta; extus pallide, intus vivide salmonea tincta;
marginibus dorsalibus rectis, ad angulum 120° separatis,
umbonibus haud extantibus; marginibus antico et ven-
trali regulariter late excurvatis; parte postica brevissima,
haud angulata, intus,dent. card, utraque valve ii., quorum
unus bifidus; lateralibus v. dextr. aequidistantibus, ant.
extant, post. parvo; nymphis rectis, haud conspicuis;
cicatr. add. post. subrotundata, ant. subrhomboidea; sinu
palii satis regulariter ovali, per iv. inter v. partes interstitii
porrecto. Long. .57, lat. .45, alt. .11 poll. (Carpenter,
December, 1864.)

Variat testa aurantiaca, rarius albida, rosaceo tincta.
(Carpenter.)

Remarks. — About 50 single valves of this little
species were collected by G. P. Kanakoff near the Mexican
boundary. The largest valve is 10.3 mm long and 8 mm
high. A large Recent left valve from Seven Mile Beach, San
Francisco, is 14.4 mm long and 12 mm high. The pallial
sinus extends in an even ellipse to about 9.9 mm from the
posterior end, does not touch the anterior adductor impres-
sion and slopes posteriorly to join the pallial line at about
7mm from the posterior end of the valve. Fresh specimens
are usually tinted with the salmon coloration characteristic
of this species.

The record of Tellina solmonea from beds of Pliocene
age in Japan given by Kanehara (1005) was later referred
to Cadella lubrica Gould by Hatai and Nisiyama (1006).

Tellina kesenensis Nomura and Hatai (1007) a Recent
species in Japanese waters, compared by its authors with
Tellina salmonea, was referred by Habe (1008) to Cadella
lubrica Gould. Tellina (Peronidia) solmonaeformis Nomura
and Hatai (1009) has a larger, higher shell which is more
trigonal in outline than that of T. salmonea.

287

[SUBGENUS OUDARDIA MONTEROSATA]

Oudardia Monterosata, Nomencl. Gen. Spec. Conch.
Medt., p. 22, 1884, “II tipe é la Tellina Oudardi,
Payr.”” — Cossmann and Peyrot, Act. Soc. Linn. Bor-
deaux, Vol. 66, (Conch. Néog. 1, Aquitaine, Tome 1.
Livr. 2), p. 263, 1910. “‘ (G. - T. Tellina compressa Br.
Viv.),” text. fig. 38, and pl. 10, figs. 21-25. — K.V.W.
Palmer, Geol. Soc. Amer., Mem. 76, p. 102, 1958. ““Type
species by original designation, Tellina oudardi Payrau-
deaesna

Type species (by original designation). — Tellina
oudardi Payraudeau [ Moll. Corse, p. 40, pl. 1, figs. 16-18,
1826. “Hab. Figari, Santa-Giulia, Favone. Rare.’ — Hanley,
Thes. Conch., Vol. 1, p. 297, pl. 66, fig. 262, 1846 (1847).
According to Monterosata this species includes Tellina
compressa Brocchi (Conch. Foss. Subapp., Vol. 2, p. 514,
pl. 12, fig. 9, 1814. “‘Fossile in Valle de Andona.”’ See
figs. 14, 15, 16, 1901); Ronchetti, Rev. Ital. Paleo. e strat.,
also Sacco, Moll. Piemonte e Liguria, Pt. 29, p. 111, pl. 23,
Mem. 5, Pt. 1, p. 85, fig. 35 (holotype), 1952].

Range. — Early Eocene to Recent.

Description. — Shell small, thin, ovoid, beaks situated
at about two-thirds the distance from the anterior end of
the valves; one anterior lateral adjacent to the cardinals; a
well developed radial ridge is present just behind the elon-
gated anterior muscle impression; exterior sculptured with
fine concentric lines of growth.

Remarks. — This subgenus has been recorded from
Pliocene to Recent in western North America. However, a
careful study of fossil Tertiary forms in this region may
reveal the presence of Oudardia in beds of an earlier age.

Boss (1010) recently placed Oudardia in the synony-
my of Angulus Megerle von Muhlfeld. Fourteen species
living in the western Atlantic were assigned to the latter
subgenus.

[ Tellina (Oudardia) modesta Carpenter]

Angulus modestus Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, pp. 602, 639, 681, August, 1864. Reprint in
Smithsonian Mise. Coll., No. 252, pp. 88, 125, 167,
1872. — Carpenter, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 17, p. 56, 1865 [as (Tellina) Angulus modestus. |
[Full deseription. ]

Not Angulus modestus Verrill. 1872.

Tellina modesta Carpenter, Dall, Proc. U. S. Nat. Mus., Vol.
1, p. 11, (later Tertiary deposits of San Diego), p. 27
[lower bed (A), San Diego Peninsula]. 1878.

Not Tellina modesta Sowerby, Proc. Zool. Soc. London,
January, 1883, p. 31, pl. 7, fig. 1, “Hab. Port Jackson
(Brazier).”

Mera modesta Carpenter, Cooper, Calif. State Min. Bur.
Seventh Ann. Rept. State Mineral., p. 250, 1888. “‘Pl. —
San Diego well.”

Tellina (Oudardia) modesta Carpenter, K.V.W. Palmer,
Geol. Soc. Amer., Mem. 76, p. 103, pl. 13, figs. 4-9,
1958. (Type specimens illustrated.)

Type specimen. — Syntypes No. 4245, United

States National Museum. (Palmer.)

Type locality. — Indicated as ‘‘Puget’s sound and the

288

neighborhood” (Carpenter, 1864); ““Hab. in sinu Pugetiano,
specimina duo juniora legit Kennedy” (Carpenter, 1865).
“Recent. Puget Sound, Washington (type).’’ (Palmer,
1958.)

Range. — Pliocene. Pleistocene and Recent. Recent,
Vancouver Island, British Columbia, to Lower California.
(Dall.)

Original description. — “Like tener, Say; but with
callus between mantle-bend and scar. White.” (Carpenter,
1864.)

Remarks. — The only definite record of Tellina
modesta in the San Diego Formation is that of Cooper.
We have seen no specimens in any of the collections from
that area. It was cited by E.K. Jordan as occurring in beds
of late Quaternary age in San Ignacio Lagoon, Lower
California. Also reported by Valentine from Timms
Point Silt, lower Pleistocene, from north border of Palos
Verdes Hills, Los Angeles Co., California. It appears to be
rare in most collections of Recent shells.

SUBGENUS MOERELLA FISCHER

Donacilla Gray, List. Brit. Anim. Brit. Mus., Pt. 6, p. 39,
1851.

Not Donacilla Lamarck, 1819.

Moera H. and A. Adams, Gen. Rec. Moll., Vol. 2, p. 396,
1856.

Not Moera Huebner, 1819, Lepidoptera.

Moerella Fischer, Man. de Conchyl., Fase. 11, p. 1147,
June 15, 1887. Sole species, Tellina donacina Linnaeus.
—Cossmann and Peyrot, Act. Soc. Linn. de Bordeaux,
Tom. 64 (Conch. Néogén. de l’Aquitaine, Tome 1,
Livr. 2), p. 224, 1910, “(G.-T.: T.: donacina L. Viv.)”
fig. 30. — Gardner, U.S.G.S., Prof. Paper 199-A, p. 94,
1943. Type by monotypy: Tellina donacina Linnaeus.
— Hertlein and Strong, Zoologica, Vol. 34, Pt. 2,p.67,
1949. “Type (by monotypy); Tellina donacina Linn-
aeus.”’ — Olsson and Harbison, Acad. Nat. Sci., Phila-
delphia, Monogr. No. 8, p. 125, 1953. “Type by mono-
typy: Tellina donacina Linné. Recent, coast of Europe
and the Mediterranean.”

Type species (by monotypy). — Tellina donacina
Linnaeus [Syst. Nat., ed. 10, p. 676, 1758. ‘Habitat in M.
Mediterraneo.” Ref. to Gualtieri, Test., pl. 88, fig. N.
1742. — Bucquoy, Dautzenberg, and Dollfus, Moll. Mar.
Roussillon, Vol. 2, Fase. 12 (Pelecypoda, Fasc. 25), p.
648, pl. 91, fig. 12, 14 (typical) and 15-19 vars., March,
1898. Mediterranean; also other localities. — Keen, Trea-
tise Invert. Paleontology, Pt. N. Vol. 2, Moll. 6, p. N618,
fig. E107, 7 a-d, 1969. “Eu. — N. Am. Pac.” — Afshar, Geol.
Soc. Amer., Mem. 119, p. 33, pl. 8, figs. 1-5, 1969. Ex-
mouth, England. Also from North Sea to Mediterranean.
For a discussion of this species see Dodge, Bull. Amer.
Mus. Nat. Hist., Vol. 100, Art. 1, p. 48, 1952].

Range. — Early Eocene to Recent. Recent west
American species live at depths of 5 to 128 meters
(3 to 70 fathoms), and perhaps deeper.

Description. — Shelli rather small for the genus,
transversely ovate, obscurely rostrate posteriorly. Sculp-
ture dominantly concentric, the Recent species often
rayed with colors. Umbones low, opisthogyrate. Lunule
and escutcheon extremely narrow, indicated but not well

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

defined. Ligament external, opisthodetic. Two cardinal
teeth in each valve, the anterior right and the posterior
left simple and laminar, the posterior right and the ant-
erior left stouter and bifid. True laterals not developed
in the left valve, though the edges are beveled to function
as laterals and are received within the lateral sockets on
the right valve; the anterior lateral more elevated and
closer to the umbo than the posterior. Pallial sinus con-
fluent ventrally with the pallial line throughout the greater
part of its extent. (Gardner, 1943.)

The pallial sinus extends anteriorly near to the an-
terior adductor impression.

Remarks. — There have been differences of opinions
among authors concerning the subgeneric assignment of
some west American species, whether to Angulus Megerle
von Muhlfeld, 1811, or to Moerella Fischer, 1887. Gardner,
1943, and Olsson and Harbison, discussed these subgenera
and assigned species from the western Atlantic, formerly
placed in Angulus, to Moerella. More recently, Boss
(Johnsonia, Vol. 4, No. 46, p. 300, 1966) discussed the
dentition of the hinges of the type species of those two
subgenera and returned to earlier authors’ usage of Ang-
ulus to include many west Atlantic species.

The hinge of Tellina lanceolata Gmelin, the type
species of Angulus, lacks a well developed posterior lat-
eral tooth in the right valve whereas the right valve of T.
donacina, the type species of Moerella, has a well developed
lateral tooth.

The subgeneric assignment of some west American
species including T. carpenteri seems open to question.
We have followed the practice of Dall, Olsson, and Keen,
in assigning T. carpenteri to Moerella. However, it is
possible that additional studies may result in placing this
species in Angulus or possibly in a new subgenus with this
or a similar west American species as type.

Eames (1011) expressed the opinion that Moerella
should be replaced by Psammotaea Lamarck (Hist. Nat.
Anim. s. Vert., Vol. 5, p. 516, July, 1818), with the type
species (selected by Children in 1823), Psammotaea don-
acina Lamarck with the type locality, “Habite l’océan
d'Europe.” This interpretation of Psammotaea has not
been generally accepted. Keen, in the Treatise on Inver-
tebrate Paleontology, placed Psammotaea in the synonymy
of Gari Schumacher.

Tellina (Moerella) carpenteri Dall
Plate 53, Figures 1, 7, 15; Plate 56, Figure 14

Angulus variegatus Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, pp. 611, 627, 639, August, 1864. Reprint in
Smithsonian Mise. Coll., No. 252, pp. 97, 113, 125,
1872. — Carpenter, Ann. Mag. Nat. Hist., Ser. 3, Vol.
14, p. 423, December, 1864. Reprint in Smithsonian
Misc. Coll., No. 252, p. 235, 1872. ‘“‘Hab. Neeah Bay
(Swan); Monterey and Catalina Island, 20-60 fathoms,
rare (Cooper).”

Not Tellina variegata Gmelin, Linn., Syst., Nat., ed. 13, p.
3237, 1791.

Tellina (Angulus) carpenteri Dall, Proc. U. S. Nat. Mus.,
Vol. 23, No. 1210, pp. 303, 320, November 14, 1900.
“This is the Angulus variegatus Carpenter, 1864, not
Tellina (Angulus) variegata Gmelin, 1792.”

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Tellina (Moerella) carpenteri Dall, K.V.W. Palmer, Geol.
Soc. Amer., Mem. 76, p. 104, pl. 13, figs. 12-16, Dec.
8, 1958. Earlier records cited.

Type specimen. — “Syntypes. — U. S. National
Museum, no. 15467 (one double and one single left
valve).”’ (K.V.W. Palmer.)

Type locality. — Originally indicated as from ‘“‘Van-
couver Island, Straits of S. Juan de Fuca, and adjoining
shores of Washington Territory, formerly known as
“Oregon”; ‘neighbourhood of Monterey” and “‘the Sta.
Barbara Group.” “Type locality, either Neah Bay, Wash-
ington, or Catalina Island, California.” (K.V.W. Palmer.)

Range. — Middle Pliocene to Recent. Recent,
Forrester Island, Alaska (Dall), to Concepcion Bay, east
coast of Lower California, in 27 to 137 meters (15 to
75 fathoms).

Occurrence in San Diego Fm. — L.A.M. 107, 305,
305A, 318, 319. S.D. 4.

Original description. — ‘‘Shape of obtusus: no callus;
rayed with pink and yellow. 20-60 fm. Cpr.’ (Carpenter,
August, 1864.)

Supplementary description. — A. testa form a A.
obtuso simili, sed costa interna omnino crente, valde
inaequilaterali, solidiore, nitente, rosaceo et flavido sub-
radiatim eleganter variegata; striis incrementi concentricis,
postice extantioribus; umbonibus postice flectentibus, ob-
tusis: parte antica prolongata, regulariter excurvata; mar-
ginibus dorsali et ventrali subparallelis, subrectis; parte
postica curtiore, subangulata: intus, dent. card. utraque
valve ii, minutis, quorum alter bifidus; v. dext. dent. lat.,
ant. curto, satis extante, post. nullo; nymphis curtis,
latis, parum concavis, subito sectis, valvis postea subalatis;
sinu palii fere cicatr. ant. tenus porrecto. Long. .72, lat.
42, alt. .15. (Carpenter, December, 1864.)

Remarks. — This species is represented in the collec-
tions by many single valves, most of which came from
localities near the Mexican boundary. The hinge and the
pallial sinus agree with those of Recent specimens of
Tellina carpenteri. The pallial sinus ascends from the post-
erior adductor impression to a rounded point then slopes
anteriorly forming an elliptical end which does not quite
touch the anterior adductor impression, then slopes post-
eriorly a short distance and joins the pallial line.

There is variation in the outline of this species as
was indicated by the specific name originally assigned to
this species by Carpenter. Many specimens agree exactly
with typical T. carpenteri, other large ones approach in
outline the more quadrate form, T. arenica Hertlein and
Strong (1012) a generally more southern form which may
be a southern subspecies of the present one. Some speci-
mens bear a general resemblance to Tellina (Oudardia)
buttoni Dall but they lack the narrow elevated ridge on the
interior of the anterior portion of the valves of that species.

SUBGENUS PERONIDIA DALL

Peronidia Dall, Proc. U.S. Nat. Mus., Vol. 23, No. 1210,
p. 291, November 14, 1900. — Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 5, p. 1014, December, 1900.

Type species (by original designation). — “‘Type,

Tellina albicans Gmelin (nitida auct.).”’ [ Linn. Syst. Nat.,

ed. 13, Vol. 6, p. 3238, 1791. No locality cited. Ref.

289

to ‘Gault. test. t. 77. f. H?” and “B (Gault. test. t. 77. f.
M?” For illustration of Tellina nitida Poli see Bucquoy,
Dautzenberg, and Dollfus, Moll. Mar. Roussillon, Vol. 2,
Fasc. 12 (Pelecypoda, Fasc. 25), p. 660, pl. 93, figs: 1-5,
1898. Recent, Mediterranean and west Africa. — Afshar,
Geol. Soc. Amer., Mem. 119, p. 84, pl. 35, figs. 1-5, 1969.]

Range. — Eocene to Recent.

Description. — Shell without laterals, having the in-
ternal character of Angulus s. s., and the external charac-
ter of Eurytellina. (Dall.)

Remarks. — This subgenus has been reported occur-
ringin widely separated areas in the world. In Europe it has
been recorded from the Eocene, and from the Aquitanian
(early Miocene) to Recent, and in the same region the
type species (1013) of Peronidia has been recorded
occurring from Helvetian, middle Miocene, to Recent.

In addition to the occurrence of Peronidia from
late Oligocene or early Miocene to Recent in western
North America, and apparently the same distribution in
Japan, it also has been reported occurring in beds of Mio-
cene age in New Zealand.

Tellina (Peronidia) bodegensis Hinds
Plate 53, Figures 9, 18

Tellina bodegensis Hinds, Zool. Voy. Sulphur, Moll., Pt.
3, p. 67, pl. 21, fig. 2, 1844 (January, 1845 on
cover). — Weymouth, State Calif. Fish Game Comm.,
Fish Bull. No. 4, p. 42, pl. 11, fig. 1, 1920. Range.
“throughout California.”” — I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 168, pl.
44, fig. 5, 1924. Earlier records cited. — Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 362,
pl. 20, fig. 13, 1931. Earlier records cited. — Fitch,
State Calif. Dept. Fish Game, Mar. Fish. Branch, Fish
Bull. No. 90, p. 73, fig. 39, 1953. “Queen Charlotte
Islands, British Columbia, to Cape San Lucas, Baja
California.”

Tellina (Peronidia) bodegensis Hinds, Burch, Min. Conch.
Club South. Calif., No. 48, p. 8, January, 1945. Dis-
cussion and earlier records.

Type specimen. — Holotype No. 74.12.11.372,
British Museum (Natural History) (Keen, Veliger, Vol. 8,
No. 4, p. 267, 1966).

Type locality. — “Inhab. Russian Bodegas.
seven fathoms, on a sandy floor.”

Range. — Pliocene to Recent. Recent from Queen
Charlotte Islands, British Columbia, to Cape San Lucas,
Lower California, Mexico, below low tide level to 27
meters (15 fathoms). “Found on most sandy beaches a-
long the outer coast and particularly in the coarse, shift-
ing sand near the entrances to bays, lagoons, and estuar-
ies.” (Fitch.)

Occurrence in San Diego Fm. — L.A.M. 305A.
U.C.L.A. 312.

Original description. — Testa transversa, oblonga,
alba, nitida, concentrice striata; latere antico majusculo,
elongato, rotundato, postico nasuto, ad extremitatem
truncato, ab umbonibus subprominulo; liris acutis, versus
umbones respectantibus; ligamento subinterno. (Hinds.)

Remarks. — A left valve of this species from Loc.
305A (LAM), near the Mexican boundary, is 51.6 mm
long and 25.8 mm high. A right valve from Loc. 312
(UCLA), also from near the Mexican boundary, is 37.8

From

290

mm in length. These valves agree in all observable shell
characters with Recent valves of Tellina bodegensis. The
pallial sinus on the smaller of the two valves extends to
within 3.5 mm of the anterior muscle impression. One of
the largest specimens of a Recent shell from Morro Bay,
California, in the Henry Hemphill collection of the
California Academy of Sciences, is 52.3 mm long, 26.4
mm high, convexity (both valves together), 10.9 mm,
the pallial sinus extends anteriorly from the posterior
margin, 33.9 mm.

Tellina bodegensis differs from T. santarosae Dall
(1014) in that the shell is thicker, more convex, less
equilateral, higher in proportion to the length, the con-
centric sculpture is less evenly spaced and the pallial
sinus is broader.

A form (1015) of T. bodegensis from the Sooke
Formation, Vancouver Island, British Columbia, of late
Oligocene or early Miocene age, closely resembles the
Recent species but differs in that the truncated posterior
end of the shell is narrower.

GENUS MACOMA LEACH

Macoma Leach in Ross’s Voy. of Discovery in H. M. S.
Isabella and Alexander, Ap. 2, p. LXII, 1819. Sole
species, Macoma tenera Leach. — Dall, Proc. U. S. Nat.
Mus., Vol. 23, No. 1210, p. 292, 1900. ““Type, Macoma
tenera Leach (= Tellina calcarea Gmelin).”’ — Grand and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 365,
1931. Type same as indicated by Dall. — Eames, Philos.
Trans. Roy. Soc. London, Ser. B, No. 627, Vol. 235,
p. 398, June 26, 1951.

Type species (by monotypy). — Macoma tenera
Leach, 1819, p. LXII. “M. concentrice striolata, epiderme
viridescente-lutea. Lat. 76° N., Long. 76° W.” [= Tellina
calcarea Gmelin, Linn. Syst. Nat., ed. 13, Tom. 1; Pars
VI, p. 3236, 1791. “Habitat frequentissima in mari island-
iam circumfluente, testa tenui.” Ref. to “Chemn. Conch.
6. t. 13. f. 186.”” Reported by Chemnitz from “wohnet in
unzaehlbarer Menge an den Ufern von Iszland und der
Ferroeischen Eylande.’’]

Range. — Eocene to Recent. Worldwide. Recent
from the littoral zone to 1300 meters (711 fathoms).

Description. — Shell roundly or elongately trigonal
in shape, slightly inflated, usually with a well developed
posterior flexure; sculpture consisting of lines of growth,
or lacking; lateral teeth lacking; pallial sinus well devel-
oped, sometimes differing in shape in the two valves.

Remarks. — A number of species of Macoma have
been recorded from strata of Tertiary age in California,
especially from Miocene to Recent. About 15 species have
been recorded from beds of Pliocene age. Four species are
recorded in the present paper from the San Diego Forma-
tion. This genus is represented by numerous Recent
species which occur abundantly in boreal west America
waters and only a slightly smaller number extend into
subtropical waters or are confined to tropical west Amer-
ican waters. Most of the latter are referred to sub-genera
which are confined to warm marine waters.

Oinomikado (1016) remarked on the pallial sinus of
a number of species of Macoma living in Japan.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Key to Subgenera of Macoma

A. Posterior area sculptured with

granules . . Macoploma.
B. Posterior area with concentric striae only
a. Dorsal margin behind ligament
produced upward Rexithaerus.

b. Dorsal margin behind ligament

not produced upward . Macoma, s. s.

SUBGENUS MACOMA, S. S.

Description. — Shell subtrigonal, the periostracum
conspicuous; usually colorless, or, if colored, without a
color pattern; flexure well marked; the pallial sinus
coalescent with the pallial line below and often discrepant
in the two valves; inhabiting the cooler seas and especially
boreal waters. (Dall, 1903.) Eocene to Recent.

Key to Species of Macoma, s. s.

A. Pallial sinus in left valve extending to
anterior adductor muscle impression
a. Shell usually 50 to 65 mm. long;

pallial sinus in right valve usually
slopes anteriorly where joining
pallial line. . . :
aa. Shell usually exceeding 50 to 65
mm. in length, pallial sinus in right
valve usually slopes slightly
posteriorly where joining pallial
line ec aoe ee

nasuta

. nasuta kelseyi

B. Pallial sinus in left valve not extending
to anterior adductor muscle impression
a. Pallial sinus in right
valve elliptical
aa. Pallial sinus in right valve subtrigonal

elimata

b. Pallial sinus extending to near
(2 mm) anterior adductor
impression; shell cuneiform in
outline

Pallial sinus extending anteriorly
about 3/5 the length of the shell;
shell elongately ovate in

outline

inquinata
bb.

acolasta

Macoma (Macoma) acolasta Dall
Plate 53, Figures 12, 13

Macoma acolasta Dall, West Amer. Sci., Vol. 19, No. 3, p
21, June 15, 1921. — Dall, Proc. U. S. Nat. Mus., Vol.
66, Art. 17, p. 19, pl. 8, figs. 2, 3, 1925. Original loc-
ality cited. — Manager, Johns Hopkins Univ. Stud.
Geol., No. 11, p. 290, 1934. San Quintin Bay, Lower
California, Pleistocene. — Addicott and Emerson, Amer.
Mus. Novitates, No. 1925, pp. 18, 21, 1959. Three
miles southeast of Punta Cabras, Lower California,
Pleistocene. — Emerson and Chace, Trans. San Diego

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Soc. Nat. Hist., Vol. 12, No. 21, pp. 338, 341, May
27, 1959. Tecolote Creek, San Diego, California,
Pleistocene.

Macoma moesta (Deshayes) variety acolasta Dall, Grant
and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p.
371, pl. 14, fig. 7; pl. 20, figs. 4a, 4b, 10, 1931. San
Quintin Bay, Lower California, and southwest of
Goleta, California, Pleistocene. — DeLong, Trans. San
Diego Soc. Nat. Hist., Vol. 9, No. 25, p. 242, opp. p.
244, 1941. Palos Verdes Sand, upper Pleistocene.

Macoma morroensis T. A. Burch, Min. Conch. Club
South. Calif., No. 47, p. 33, pl. 2, figs. 46, 47, April,
1945. “from Morro Bay, Calif.”

Type specimen. — No. 333113, United States
National Museum.

Type locality. — ‘Pliocene or early Pleistocene of
San Quintin Bay, Lower California,’ Mexico.

Range. — Middle Pliocene to Recent in southern
California; Pleistocene in southern California and in
northern Lower California; Recent from Bodega Bay to
San Diego, California, from the intertidal zone to 73
meters (40 fathoms).

Occurrence in San Diego Fm. — U.C.L.A. 1386.

Original description. — Shell small, inequilateral, in-
equivalve, posterior end somewhat bent to the right, sur-
face smooth except for faint incremental lines which are
stronger on the posterior area; beaks not prominent, near-
er the posterior end; both dorsal slopes somewhat arched,
anterior end evenly rounded, base slightly arcuate, poster-
ior end very slightly rostrate; left valve more convex; hinge
feeble, right valve with two small cardinals, left valve with
a single bifid tooth; pallial sinus in the left valve, sub-
ovate, reaching a little beyond the middle of the valve, the
lower two-thirds coalescent with the pallial line; in the
right valve the sinus is almost triangular. Height 12;
length 22; diameter 5.6 mm. (Dall.)

Remarks. — This species is represented in the San
Diego Formation by a single specimen retaining both
valves, length 25.6 mm, height, 15.4 mm. This is the
first record of this species in the San Diego Pliocene. It is
known to occur at several localities in beds of Pleistocene
age.

The present specimen agrees in all particulars with
Dall’s original illustration of Macoma acolasta except
that the pallial sinus bends farther anteriorly before joining
the pallial line at an acute angle. However, the amount
of variation of this feature in Dall’s species is unknown.
All other shell characters are so similar that we refer the
present fossil to M. acolasta.

The shell of Macoma acolasta differs from that of
M. moesta Deshayes (1017), an Arctic and boreal species,
in that the shell is more elongated and the posterior
end bears a gentle but distinct flexure.

Grant and Gale recorded, questionably, the occur-
rence of Macoma moesta in beds of late Pliocene age in
San Joaquin Valley, California, but we have not seen
specimens.

The illustrations of the type specimen of Macoma
morroensis T. A. Burch, although not clear in detail, agree
with M. acolasta in all observable particulars. A paratype,
No. 8344, in the collections of the California Academy
of Sciences, an immature specimen about 17 mm in
length, agrees well with the early stages of development
shown in Dall’s illustration of M. acolasta.

291

Macoma (Macoma) elimata Dunnill and Coan
Plate 53, Figure 5

Macoma calcarea Gmelin, Dall. U. S. G. S., Prof. Paper
59, p. 126, pl. 14, fig. 8, 1909. “Miocene of Coos
Bay, Oregon.” [Pliocene] — Waterfall, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 18, No. 3, table
opposite p. 78, 1929. Upper Pico Formation, Plio-
cene. — Cummings, Touring, and Brabb, Calif. Div.
Mines Geol., Bull. 181, p. 208, photo 19, No. 2, 1962.
San Gregorio Member of the Purisima Formation, San
Mateo Co., Calif., Pliocene. — Faustman, Univ. Calif.
Publ. Geol. Sci., Vol. 41, No. 2, p. 122, pl. 1, fig. 4,
1964. Humboldt Co., Calif., also other localities,
Pliocene.

Not Tellina calcarea Gmelin, Linn. Syst. Nat., Tome 1,
Pars. 6, p. 3236, 1791.

“Macoma sp. nov. =M. calcarea, Arnold 1903,” Crickmay,
Jour. Geol., Vol. 37, No. 7, pp. 624, 627, 628, 631,
1929. Deadman Island, Pleistocene.

Macoma calcarea Gmelin (small var.), A. Clarke, Trans.
San Diego Soc. Nat. Hist., Vol. 7, No. 4, table opp.
p. 30, 1931. Timm’s Point, Pleistocene. — Wood-
ring, Bramlette, and Kew, U. S. G. S., Prof. Paper 207,
p. 84, pl. 33, fig. 6, 1946. Timms Point Silt. — Wood-
ring, Vedder, and Trumbull, also Winterer and Dur-
ham, U.S.G.S., Prof. Paper 334-H, p. 302, 1962 (as
Macoma ef. M. calcarea). Los Angeles Co., Pliocene.

Not Tellina calcarea Gmelin.

Macoma elimata Dunnill and Coan, Nat. Mus. Canada,
Nat. Hist. Papers No. 43, p. 1, figs. 1, 2 (a-e), 3, 6, (2a,
2b), December 9, 1968. — Dunnill and Ellis, Nat.
Mus. Canada, Nat. Hist. Papers No. 45, p. 15, figs.
4, 2a-d; 9f, January 10, 1969.

Type specimen. — Holotype No. 46070, National
Museum of Canada, Division of Mollusks.

Type locality. — “from the north end of Moresby
Island, Satellite Channel, Vancouver Island, British Col-
umbia (48° 44’N. by 120° 19’W.)... in silty sand at a
depth of 49 meters on 7 June 1967.”

Range. — Middle Pliocene to Recent. Recent from
Craig, Alaska, to off Redondo Beach, Los Angeles Co.,
California, in 15 to 476 meters (7 to 260 fathoms), in
silty and clayey sand, and sand.

Occurrence in San Diego Fm. — L.A.M. 107.
U.C.L.A. 2359.

Original description. — The shell is moderately in-
flated, reaching its maximum thickness well anterior to
the umbos. The umbos are fairly prominent and slightly
raised above the dorsal margin. The shell is ovate anterior-
ly; posteriorly the dorsal margin is straight and steeply
sloping. The anterior end is truncate. The periostracum is
greenish grey and flaky and is little eroded except around
the umbos. The shell is chalky white and is covered with
fine, concentric growth lines. The posterior dorsal margin
has a flattened, concave escutcheon. The valves are
flexed toward the right posteriorly.

The interior is white with a low polish and silky
lustre. The pallial sinuses are discrepant, long in the left
valve (stopping just short of the anterior adductor
sear), much shorter and lower in the right valve. Both
pallial sinuses loop back along the pallial line and are con-
fluent with it beneath the umbos. The posterior cruciform

292

muscle scar occurs near the ventral - posterior tip of the
pallial line and divides into two parts, with a small
anterior element. The anterior cruciform scar lies immed-
iately ventral to the pallial line. There are two cardinal
teeth in each valve. The left anterior and right posterior
teeth are projecting and bifid, while the right anterior
and left posterior teeth are projecting, lamellar, and frag-
ile. The left posterior tooth is the thinnest and frequently
breaks off when the valves are opened. The holotype is
27.2 mm long, 20.7 mm high, and 9.6 mm thick, (both
valves).

Remarks.—Two specimens, the larger one 27.2 mm
long, from the San Diego Formation, are present in the
collections of the University of California at Los Angeles.
These are identical with a series of 29 specimens, the
largest one 32 mm long, from Loc. 3 (CAS) in strata of
Pliocene age at Coos Bay, Oregon, from which beds a
specimen was illustrated by Dall under the name of Mac-
oma calcarea. One imperfectly preserved specimen from
Loc. 107 (LAM) is comparable to M. elimata. Specimens
cited as M. calcarea by Waterfall from the upper Pico For-
mation in Ventura Co., California, also are referable to
M. elimata.

Macoma elimata resembles M. calcarea Gmelin but
differs from that species in the straighter dorsal margin
posteriorly and especially in the somewhat flattened or
slightly concave escutcheon (see Dunnill and Coan, 1968,
figs. 2a-e, and illustrations of M. calcarea Gmelin, figs. 2f,
9, 10). It apparently does not attain the size of large spec-
imens of M. calcarea, that is, about 33 mm in length in
comparison to 50.8 mm. The spermatozoa of Recent
specimens of the two also are said to differ. ~

Madsen (1018) pointed out that specimens of M.
calcarea from the Atlantic coast of the eastern United
States are generally more elongate in outline. This is
well shown in Gould’s illustration (1019) of ‘‘Tellina
proxima” from that region. ;

The Macoma calcarea group apparently had its
origin in the northern Pacific as suggested by MacNeil
(1020). Hatai and Nisiyama (1021) reported M. calcarea
from Japan from strata believed to be of Miocene age and
they also mentioned a subspecies, M. (s. s.) calcarea izur-
ensis Yokoyama from the Akadaira Formation of Oligo-
Miocene age. Another subspecies, M. calcarea yoko
hamaensis Aoka (1022) was described from the Nakazoto
Formation of late Pliocene age. In England, the M. cal-
carea group is reported to make its first appearance in the
Red Crag beds, to which many authors assign an early
Pleistocene age. Malatesta (1023) recently discussed the
occurrence and identification of M. calcarea and sub-
specific forms in the Pleistocene deposits of Italy and
adjacent regions.

Two varieties of Macoma calcarea from the Arctic
were described by Soot-Ryen (1024). An excellent dis-
cussion of the variation of the shell and the habitat of
M. calcarea was given by Odhner (1025) and later by Mac-
Ginitie (1026).

The species described as Tellina albaria Conrad (see
Moore, E., U. S. G. S., Prof. Paper 419, p. 80, pl. 28, figs.
8, 9, 12; pl. 29, fig. 9, 1963), from Astoria, Oregon, of
middle Miocene age, are somewhat more elongate in out-
line, and may be a precursor of M. elimata. Macoma
twinensis Clark, from beds said to be of late Oligocene
age, is another member of this group.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Macoma (Macoma) inquinata Deshayes
Plate 52, Figures 1, 10

Tellina inquinata Deshayes, Proc. Zool. Soc. London for
1854, p. 357 (issued May 16, 1855). — Sowerby,
Conch. Icon., Vol. 17, Tellina, species 164, pl. 30, fig.
164, 1867. “Hab. Vancouver’s Island.’’ Reproduction
of Sowerby’s figure by Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 367, pl. 20, fig. 5,
1931. Pliocene to Recent.

Macoma inquinata Deshayes, Reagan, Trans. Kansas Acad.
Sci., Vol. 22, p. 204, 1909. Quillayute Formation,
western Washington, Pliocene. Also “Purisima-San Di-
ego.”’ — Packard, Univ. Calif. Publ. Zool., Vol. 14, No.
2, p. 278, pl. 23, Figs. 2a, 2b, 3a, 3b; pl. 24, Figs. 1a,
1b; pl. 48 (map of distribution). 1918. “Bering Strait to
Monterey, California (Dall).”” Recent. — I. S. Oldroyd,
Publ. Puget Sound Biol. Sta., Vol. 4, p. 54, pl. 32, figs.
2a, 2b, 3a, 3b, 1924. “San Juan Island, Wash.” “Bering
Strait to Monterey, Calif.; Japan.” — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
172, pl. 45, figs. 2a, 2b, 3a, 3b, 1924. Pliocene to Re-
cent. (Illustrations same as in preceding reference.)
—Salisbury, Proc. Malacol. Soc. London, Vol. 21, pt. 2,
p. 85 (in text), pl. 12, fig. 5 (type), 1934. “from the
Columbia River.”

Type specimen. — British Museum (Natural History)
(A.M. Keen, written comm., January 24, 1967.)

Type locality. — “Hab. Columbia.” [“‘from the
Columbia River’ (Salisbury). ]

Range. — ? Late Miocene; Pliocene to Recent. Re-
cent from Bering Strait to San Pedro, California, from
intertidal zone to 110 meters (60 fathoms).

Occurrence in San Diego Fm. — L.A.M. 124.
U.C.L.A. 1386.

Original description. — T. testa trigona, crassa, sol-
ida, depressiuscula, inaequilaterali, sub epidermide squa-
lide fusca albofusca, ferrugineo inquinata, transversim ir-
regulariter striata, intus candida; latere antico late obtuso,
subsemicirculari, superne parum declivi; latere postico cu-
neiformi, attenuato, superne recto et declivi, extremitate
oblique truncato, inferne oblique angulato, flexura parum
perspicua; ligamento praelongo, incrassato; cardine bid-
entato, dentibus lateralibus nullis; sinu pallii magno, pro-
fundo, superne gibboso, deinde declivi et apice acuto.
(Deshayes.)

Remarks. — Two valves of Macoma inquinata from
Balboa Park in the collections of the Los Angeles County
Museum agree in all details with Recent specimens of this
species. The larger one, a right valve, is 44 mm long,
32.8 mm high, and the convexity (one valve), 10.2 mm.
The portion of the pallial line visible is identical with Re-
cent forms. A Recent large right valve from Unalaska
Island, Alaska, in the collections of the California A-
cademy of Sciences, is 65 mm long, 45.6 mm high, con-
vexity (one valve), 12.2 mm.

Two small valves from Balboa Park, San Diego, in
the collections of the University of California at Los
Angeles, are referred with question to Macoma inquinata.
The left valve is incomplete, the right one measures,
length, 21 mm, height, 16 mm, convexity, 4.2 mm. These
compare favorably with juvenile specimens of Macoma
inquinata except that the pallial sinus on the right

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

valve extends closer to the anterior adductor muscle
impression. There is a possibility that these fossils are
referable to the form described from the Etchegoin Plio-
cene, Macoma affinis plena Stewart (1027). The general
outline is similar but the shape of the pallial sinus of M. a.
plena is not well known. We, therefore, provisionally refer
the present fossils to the Recent M. inquinata. Based on
external features these fossils hardly differ from shells of
M. balthica Linnaeus of the same size.

This is the first record of the occurrence of Macoma
inquinata in the San Diego Formation but the species is
known to occur in beds of Pliocene age elsewhere on the
Pacific Coast.

There has been confusion of Macoma inquinata
with M. irus Hanley (1028) which was described without
information as to the locality from which it came. Later
it was attributed to “Guinea?” by its author. Hanley
stated, “Evidently a perforating species, allied to the Pet-
ricola ochroleuca of Lamarck, the true Tellina fragilis of
Linnaeus’s collection.”’ Salisbury (1029) concluded from
a study of type specimens in the British Museum of
Natural History that M. irus is identical with M. inquinata
and with the species described as Tellina contabulata
Deshayes (1030) from Chinese seas, which locality Salis-
bury believed is erroneous for that species. However,
Keen (1031) recently has shown that the west American
species should bear the name Macoma inquinata. Some re-
cords of Macoma inquinata from Japan have been assigned
to Macoma anser Oyama (1032).

Macoma inquinata arnheimi Dall (1033), described
from Alaskan waters, has a higher and more rounded
shell than the typical form. Faustman, 1964, reported
this subspecies from the Rio Dell Formation in Hum-
boldt Co., California.

Macoma inquinata affinis Nomland (1034), des-
cribed from beds of Pliocene age in San Joaquin Valley,
California, attains a larger size than M. inquinata, the
height is greater in proportion to the length, and the
pallial sinus does not extend so close to the anterior ad-
ductor muscle impression. This form bears a general re-
semblance to the Japanese M. anser Oyama but the
oriental form is more rounded, the pallial sinus in the
left valve is more angulated above and in the right valve
it is more distant from the anterior adductor muscle
impression.

A fossil form cited as Macoma aff. M. inquinata
Deshayes, was reported by Hickman (1035) from beds
believed to be of Oligocene age in Oregon.

Macoma (Macoma) nasuta Conrad
Plate 53, Figure 10; Plate 54, Figure 6

T[ellina].
phia, Vol. 7, Pt. 2, p. 258, 1837.

Not Tellina nasuta Conrad, in J. D. Dana, U. S. Exped.
(Wilkes), Vol. 10, Geol., p. 725, October, 1849. Re-
named Tellina subnasuta by Conrad in 1865.

Macoma nasuta Conrad, Dall, Proc. U. S. Nat. Mus., Vol.
1, p. 11, “Later Tertiaries,”’ San Diego; p. 27, “sand
bed (B),” San Diego peninsula, 1878. — Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 163, 1903. “‘Pacific Beach.”
and “San Diego (Arnold),’’ Pliocene. — J. P. Smith,

nasuta Conrad, Jour. Acad. Nat. Sci. Philadel-

293

Proc. Calif. Acad. Sci., Ser. 4, Vol. 3, pp. 171, 181,
1912. “‘Purisima-San Diego.” Pliocene. — Packard, Univ.
Calif. Publ. Zool., Vol. 14, No. 2, p. 279, pl. 23, figs.
la, 1b, 1c, 1d; pl. 49 (distribution), 1918. San Fran-
cisco Bay area. Range, Aleutian Islands, Alaska, to
Lower California.—I.S. Oldroyd, Publ. Puget Sound
Biol. Sta., Vol. 4, p. 53, pl. 32, figs. 1a, 1b, 1c, 1d,
1924. (Same illustr. as shown by Packard.) Kodiak Is-
land and Cook Inlet, Alaska, to Scammon’s Lagoon,
Lower California.—I.S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 174, pl. 45, figs. 1a, 1b,
le, 1d, 1924. “San Diego,” Pliocene. Also other re-
cords.—Waterfall, Univ. Calif. Publ. Bull. Dept. Geol.
Sci., Vol. 18, No. 3, opp. p. 78, 1929. “San Diego
Pliocene.”—Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 366, 1931. “Middle Pliocene of Pa-
cific Beach, San Diego (Arnold, 1903).’’ — Fitch, State
Calif. Dept. Fish Game, Mar. Fish. Branch, Fish Bull.
No. 90, p. 74, fig. 40, 1952. “‘Kodiak Island, Alaska, to
Cape San Lucas, Baja California,’ Recent.

Type specimen. — Syntype No. 1861.5.21.158,
British Museum (Natural History). (See A. M. Keen, Vel-
iger, Vol. 8, No. 3, p. 170, 1966.)

Type locality. — “Inhabits coast of California near
Sta. Diego.”

Range. — Oligocene (Loel and Corey); middle Oli-
gocene (Weaver); early Miocene to Recent. Recent from
Kodiak Island, Alaska, to Cape San Lucas, Lower Calif-
ornia, from intertidal zone to about 46 meters (25
fathoms). “mostly found in heavy mud or muddy sand
of sheltered bays, lagoons and estuaries,” at depths of
four to eight inches beneath the mud (Fitch).

Occurrence in San Diego Fm. — C.A.S. 957, 1178,
1400. S.D. 21, 80.

Original description: Shell ovate, compressed,
smooth but not polished; anterior side dilated; posterior
side cuneiform, extremity truncated, much above the line
of the base; fold carinated on the superior valve; beaks
central, slightly prominent; epidermis extremely thin and
deciduous, finely wrinkled, brown; palleal impression of
the left valve joining the anterior cicatrix at its lower
posterior angle. Length, an inch and three quarters.
Height an inch and a third. (Conrad.)

Remarks. — A few specimens, none perfectly pre-
served, were collected in the San Diego Formation. These
do not differ from Recent valves of Macoma nasuta
in adjacent marine waters.

This species occurs without change throughout the
latter half of the Cenozoic in western North America. It
is characterized by the nearly centrally placed beaks
and bent, obliquely pointed, posterior end. The pallial
sinus in the right valve extends to the anterior adductor
impression but in the left valve it extends anteriorly,
then slopes to and coalesces with the pallial line at about
two - thirds the length of the shell. This varies, and in
occasional specimens the sinus slopes slightly posteriorly
before joining the pallial line.

Macoma jacalitosana Arnold (U. S. G. S., Bull. 396,
p. 65, pl. 16, fig. 2, 1909 (issued January 15, 1910), des-
cribed from the Jacalitos Formation of early Pliocene age,
in the San Joaquin Valley, California, is a similar form.

A Recent species in Japanese waters formerly cited
as Macoma nasuta is now referable to M. tokyoensis Maki-
yama (1036). It is smaller and has a differently shaped

294

pallial sinus than that of M. nasuta.

Macoma nasuta was recorded by Kanehara (1037)
as occurring in beds of Pliocene age in Japan but it is not
among the species from the Cenozoic of Japan cited by
Hatai and Nisiyama (1038).

Macoma aomoriensis Nomura (1039) and M. ishi-
moriensis Aoka (1040), described from Miocene beds in
Japan, were compared by their authors with M. nasuta.

Macoma nasuta also has been recorded from late
Tertiary strata in the Schmidt Peninsula, Kamtschatka, by
Khomenko and by Slodkewitsch (1041). However, the
posterior end shown in illustrations by the latter author
is less pointed and the shell is correspondingly more sub-
orbicular in outline than is that of M. nasuta.

Macoma nasuta, known as the ‘“‘bent-nost clam,”
is used for food along the coast of California. According
to Fitch, this clam always lies on the left side and its
siphons are extended to the surface for feeding and are
freely withdrawn and re-extended to a different spot.

Macoma (Macoma) nasuta kelseyi Dall
Plate 52, Figures 5, 9, 11, 12
Text-Figure 13

Macoma kelseyi Dail, Trans. Wagner Free Inst. Sci., Vol.
3, Pt. 5, p. 1052, pl. 49, fig. 7, December, 1900. —
Schuchert, Dall, et al., U. S. Nat. Mus., Bull 53, Pt. 1,
p. 381, 1905. “Pleistocene. City Park, San Diego, Calif-
ornia.”” — I. S. Oldroyd, Publ. Puget Sound Biol. Sta.,
Vol. 4, p. 58, 1924. “Known alive only from off
Brown Island, Wash., in 3-4 fathoms.” — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
171, 1924. Earlier locality records cited.

Macoma nasuta kelseyi Dall, Woodring, in Woodring and
Bramlette, U. S. G. S., Prof. Paper 222, pp. 65, 87, pl.
20, figs. 2, 8 (Graciosa Ridge, 2.9 miles south of Or-
cutt, California), 1950. Also, Balboa Park, San Diego
Pliocene.

Type specimen. — No. 147690, United States Nat-
ional Museum.

Type locality. — “Pleistocene of San Diego, Calif-
ornia, obtained in the City Park by Dr. R. E. C. Stearns.”
[Pliocene. ]

Range. — Middle Pliocene (San Diego Formation;
Careaga Formation of Santa Maria district) to Recent.
Recent from Puget Sound to Halfmoon Bay, California,
(and probably extending over most of the range of Mac-
oma nasuta), in 5 to 7 meters (3 to 4 fathoms) and per-
haps deeper.

Occurrence in San Diego Fm. — C.A.S. 1402, 1415.
L.A.M. 124, 323. S.D. 4; 29, 79, 80, 3206, 5679.
U.C.L.A. 302, 1383, 1386.

Original description.—Shell large, solid, heavy, com-
pressed, slightly flexed; beaks subcentral, prominent,
pointed; anterior end evenly rounded into an arcuate base
and dorsal margin; posterior end lanceolate, the dorsal
margin nearly rectilinear; surface sculptured only by
strong, rather irregular lines of growth; hinge-plate short,
broad, and strong; teeth normal, elongated, large; pallial
sinus discrepant in the two valves; left valve with the
upper part of the sinus sinuous, extending from the post-
erior to the anterior adductor, behind which is a
thickened, obscure ray; right valve with the sinus short,

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

gibbous, the anterior end rounded, thence the line curves
backward before coalescing with the pallial line below; in
the left valve the sinus is coincident with the whole of
the pallial line below. Long. 86, alt. 56, diam. 20 mm.
(Dall.)

Remarks. — A number of paired and unpaired
valves of this subspecies are present in the collections
from the San Diego Formation. A large valve, from Bal-
boa Park, is 87 mm long, 59 mm high, convexity (one
valve), 10.5 mm. The largest specimen in the collections,
a right valve from Loc. 124 (LAM), below Snyder’s Con-
tinuation School, is 106.8 mm long and 77 mm high.
The pallial sinus joins the pallial line 75 mm from the
posterior end of the valve.

The very large size, thicker shell and slightly bent
posterior end are characters included as a basis upon
which the present form was separated by Dall as a sub-
species of Macoma nasuta. Dall also believed that the
supspecies M. n. kelseyi differed in the character of the
pallial sinus in the right valve which he stated bent post-
eriorly before coalescing with the pallial line. Examina-
tion of a number of right valves reveals that there is varia-
tion in this character. In some specimens of M. n. kelseyi
the pallial line does, in others it does not, bend poster-
iorly before joining the pallial line. Hertlein and Strong
(1042) mentioned that this character is variable and con-
sidered it open to question whether M. n. kelseyi repre-
sents a species, subspecies or merely a very large form of
M. nasuta. The present authors are inclined to the latter
view but it is possible that this large form may have
ecological or stratigraphic significance and we therefore
favor its retention as a subspecies, at least for the pre-
sent.

Text Fig. 13.
Hypotype (San Diego Society of Natural History), left
valve, from Loc. 29 (SD) south of Laurel Street bridge,

Macoma (Macoma) nasuta kelseyi Dall.

Balboa Park, San Diego; Pliocene.
(Drawn by E. H. Quayle.)

Length 86.8 mm.

This subspecies occurs in the Careaga Sandstone,
of Pliocene age, in the Santa Maria district and in Pliocene
beds at Cedros Island and at Bahia Tortolo (Turtle Bay),
Lower California, as well as at San Diego. Addicott and
Emerson (1043) reported this subspecies from beds of
Pleistocene age at Punta Cabras, Lower California (Lat.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

29° 57’ N.). A Recent large right valve from Halfmoon
Bay, California, is 90.8 mm in length. It appears quite
probable that this subspecies may occur over much if not
all the range of M. nasuta.

SUBGENUS MACOPLOMA PILSBRY AND OLSSON

Macoploma Pilsbry and Olsson, Proc. Acad. Nat. Sci.
Philadelphia, Vol. 93, p. 68, September 9, 1941.
Type species (by original designation). — “Type
Macoma ecuadoriana new species.” [Macoma (Maco-
ploma) ecuadoriana Pilsbry and Olsson, 1941, p. 69, pl.
19, fig. 5. ““Canoa formation, Punta Blanca,” Ecuador,
Pliocene. |

Range. — Pliocene to Recent, eastern Pacific. Re-
cent, tropical eastern Pacific.

Original description. — Shell elongate, nearly equi-
valve, the left valve a little larger and more convex than
the right; surface with the granulation of Periploma, de-
veloped most strongly on the posterior area, finer or ab-
sent from the rest of the surface; hinge of Macoma, with
a small cardinal tooth in the left valve and no laterals.
(Pilsbry and Olsson.)

Remarks. — The subgenus Macoploma differs from
all other subgenera of Macoma by the presence of gran-
ules on the posterior area and sometimes over the whole
shell, similar to Periploma and Thracia.

The subgenus Macoploma is here recorded for the
first time from strata of Pliocene age in California. It also
is known to occur in strata of Pliocene age in Ecuador
and Costa Rica and in sands of late Pleistocene age at
San Pedro, California.

Macoma (Macoploma) medioamericana Olsson
Plate 52, Figures 6, 8

Macoma (Macoploma) medioamericana Olsson, Bull. Am-
er. Paleo., Vol. 27, No. 106, p. 196 (44), pl. 17 (4) fig.
8, December 25, 1942. Cited on p. 242 (90) (as ‘‘Mac-
oma (Macoploma) medioamerciana.”’). — Hertlein and
Strong, Zoologica, Vol. 34, Pt. 2, p. 938, 1949. ‘“‘Arena
Bank, Gulf of California, to Panama,” in 29 to 82 met-
ers.—Keen, Sea Shells of Tropical West America (Stan-
ford University Press), p. 180, fig. 426, 1958. “The
Gulf of California to Panama, intertidally and offshore
in depths to 45 fathoms; rare.”

Psammacoma (Macoploma) medioamericana Olsson, Ols-
son, Mollusks of the Tropical Eastern Pacific (Paleo.
Res. Inst.: Ithaca, New York), p. 416, 1961. Gulf of
California to Panama.

Type specimen. — No. 5004, Paleontological Re-
search Institution, Ithaca, New York.

Type locality. — ‘‘Pliocene. Quebrada Penitas, Costa
Rica.”

Range. — Pliocene to Recent. Recent from the Gulf
of California to Atacames, Ecuador, from intertidal zone
to 82 meters (45 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305A.

Original description. — Shell of medium or large
size, elongate, delicate; the valves are subequal, the left
being slightly larger and more convex than the right which

295

is somewhat flexed or depressed in the middle; beaks,
placed at the posterior one-third, are small and pointed;
anterior side nearly twice the length of the posterior,
obliquely rounded at the end; posterior side somewhat
narrowed, obliquely truncated at the end; surface is
marked with lines of growth, smoother in the middle,
coarse and more or less granulose on the sides; each valve
has a narrow, submarginal zone at the posterior end, its
surface earthy in appearance and bordered anteriorly by
a line of coarse granules; hinge unknown. Length, 62
mm.; height, 30 mm.; diameter, 12 mm. (Olsson.)

Remarks. — A left valve 65 mm long and 32.8 mm
high, in the collection from Loc. 305 A (LAM) near the
Mexican boundary, agrees in all observable shell charac-
ters with Macoma (Macoploma) medioamericana Olsson.
The shell is somewhat worn but granules are present on
the posterior area and along the anterior ventral margin.
The pallial sinus on the present specimen is obscured by
hard matrix. The hinge bears two cardinal teeth.

The present specimen resembles the illustration of
the type specimen of M. ecuadoriana described from
strata of Pliocene age in Ecuador. Macoma medioamer-
icana and M. ecuadoriana are similar as pointed out by
Hertlein and Strong. According to Olsson the shell of M.
medioamericana is proportionately longer than that of
M. ecuadoriana and “It differs also by its coarser, more
earthy, or Thracia-like granulation of the surface on the
posterior submargins.” The granulation on M. ecuador-
iana was originally described as present on the posterior
area but fine or lacking elsewhere.

An imperfect left valve of a Macoma, 20.6 mm
long and 14.4 mm high, from Loc. 305 A (LAM) near
the Mexican boundary, is comparable to Macoma medio-
americana Olsson. No granules are observable on the
posterior area but this may be due to erosion of the
shell surface. The shape and growth lines agree with a Re-
cent left valve of M. medioamericana, 33.3 mm long
from Loc. 27557 (CAS) near Punta Arenas, Costa Rica.
The hinge of the fossil specimen has a similar grooved an-
terior cardinal tooth but what was probably the thin
posterior cardinal lamella is represented only by a low
eroded remnant.

Well preserved specimens of M. medioamericana
collected by George Kanakoff from sands of late Pleisto-
cene age at San Pedro, California, agree exactly with
Recent specimens of that species from the Gulf of
California and Central America.

Recent specimens of this species have two cardinal
teeth in the hinge of each valve, the posterior tooth
usually thinner and more lamellar than the anterior one.
The pallial sinus in a left valve 100 mm long ascends
rather high to a slightly flattened curve beneath the beak
then descends to a rounded point about 68 mm from the
posterior end of the valve and then extends posteriorly
to where it joins the pallial line about 44 mm from the
posterior end of the shell.

SUBGENUS REXITHAERUS CONRAD

Rexithaerus Conrad in Tryon, “Catalogue of the family
Tellinidae,” Supl., Amer. Jour. Conch., Vol. 4, No.
5, p. 104, May 6, 1869. Species cited: ‘“‘M. secta,
Conrad” (T. ligamentina, Desh. in synon.), and ‘‘M.
denticulata, Deshayes” (T. inaequivalvis, Sowb. in

296

synon.). — Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 5, p. 1045, December, 1900.

Type species (designated by Dall, Proc. U. S. Nat.
Mus., Vol. 32, No. 1210, p. 292, November 14, 1900.) —
“Type, Macoma secta Conrad.” [= Tellina secta Conrad,
Jour. Acad. Nat. Sci. Philadelphia, Vol. 7, Pt. 2, p. 257,
1837. “Inhabits muddy marshes; Sta. Diego.”’ Illustrated
by I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol.
Sci., Vol. 1, p. 178, pl. 44, fig. 8, 1924. “Vancouver
Island to the Gulf of California. Also Pliocene and
Pleistocene. — Weymouth, State Calif. Fish Game Comm.,
Fish Bull. No. 4, p. 44, pl. 12, figs. 3 and 4; pl. 13, fig. 1,
1920. California coast. — Fitch, same series, Fish Bull.
No. 90, p. 75, fig. 41, 1953. “British Columbia to Cape
San Lucas, Baja California.”’]

Range. — Miocene to Recent. Recent from the
Gulf of California to Japan.
Description. — Shell large, inequivalve, with a

smooth surface, a large and strong deep-set ligament,
behind which the dorsal margin is conspicuously pro-
duced upward. (Dall, 1900.)

Remarks. — This subgenus is represented in the San
Diego Formation by one species and one subspecies.
Three species have been cited from the late Tertiary of
California.

Key to Species And Subspecies of Rexithaerus

A. Beaks on adult specimen
about 25 mm. from posterior
end; not strongly rostrate
posteriorly . : indentata

B. Beaks on adult specimen about
30 mm. from posterior end;
strongly rostrate

posteriorly . (subspecies) tenuirostris

Macoma (Rexithaerus) indentata Carpenter
Plate 52, Figures 3, 4, 7

Macoma Indentata Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, pp. 611 (“‘S. Diego”), 639 (indicated as from
“The region between S. Diego and S. Pedro’), issued
August, 1864. Reprint in Smithsonian Misc. Coll., No.
252, pp. 97, 125, 1872.—Carpenter, Proc. Calif. Acad.
Sci., Vol. 3, p. 208, 1866. ‘Hab. San Pedro, (young,
living, Palmer;) large, dead valves, Cooper.’’ — Dall,
Proc. U. S. Nat. Mus., Vol. 1, p. 11, “later Tertiary”
of San Diego; p. 27, “sandbed (B)” about 12 ft.
thick, over Bed (A), San Diego Peninsula, 1878,
—Arnold, Mem. Calif. Acad. Sci., Vol. 3, p. 161, pl.
16, fig. 1, 1903. Several localities cited, Miocene to
Recent. — Packard, Univ. Calif. Publ. Zool., Vol. 14,
No. 2, p. 277, pl. 25, fig. 4, 1918. “San Francisco to
Lower California,” Recent.—I. S. Oldroyd, Publ. Puget
Sound Biol. Sta., Vol. 4, p. 55, pl. 41, fig. 4, 1924.
(Reproduction of figure given by Packard, 1918.)
Recent. — I. S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 178, pl. 44, fig. 4, 1924.
(Under section Rexithaerus). (Reproduction of figure

given by Packard, 1918.) ‘‘Santa Barbara, California to

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Lower California,” Recent. Also Pliocene and Pleis-
tocene in California.
Macoma (Rexithaerus) indentata Carpenter, K. V. W. Pal-
mer, Geol. Soc. Amer., Mem. 76, p. 109, pl. 16, figs.
1, 2, 1958. (Type specimen illustrated.) ““Recent. San
Pedro, California (type); Puget Sound, Washington, to
Lower California (Dall.” Also Miocene to Recent.
Type specimen. — No. 15229, United States Nat-
ional Museum.

Type locality. — ‘“‘Recent San Pedro, California
(type)” (K. V. W. Palmer, 1958.)
Range. — Late Miocene to Recent. Recent from

Puget Sound, Washington, to Cholla Bay (1044) in the
Gulf of California, Sonora, Mexico, in 15 to 46 meters (9
to 25 fathoms), in sandy mud or in sand.

Occurrence in San Diego Fm. — C.A.S. 1186,
28892. L.A.M. 305, 305A, 319. U.C.L.A. 294, 2359.

Original description: “Like secta, jun., but beaked,
indented, and ventrally produced.’’ (Carpenter, 1864.)
Long. 2.20, lat. 1.40, alt. 0.56 (Carpenter, 1866.)

Remarks.—This species is represented by a few spec-
imens in the collections from the San Diego Formation.
The most perfect one, a right valve from near the Mex-
ican boundary, in the collections of the Los Angeles
County Museum, is 55.2 mm long and 33.3 mm high. It
agrees in all essential shell characters with Recent speci-
mens of this species.

The subspecies Macoma indentata tenuirostris Dall
is decidedly more elongated than the typical form.

Macoma indentata flagleri Etherington (1045) des-
cribed from beds of middle Miocene age in western Wash-
ington was said to be characterized by the “slightly more
prominent beak and the posterior fold is only slightly de-
veloped on it as compared with the recent form.”

Arnold mentioned a probable relationship between
Macoma indentata and the species which he described as
Macoma vanoviecki (1046) from beds of Pliocene age in
the San Joaquin Valley. Grant and Gale suggested that
Arnold’s species was probably but a variety of M. inden-
tata. However, an examination of a cast of the type speci-
men of M. vanvilecki shows it to differ from the Recent
species as stated by Arnold; namely, in the much longer
and much more convex form. The fossil which Nomland
(1047) illustrated under the name of Macoma vanvlecki
from the Etchegoin Formation apparently scarcely diff-
ers from Recent M. indentata and is not referable to the
species described by Arnold.

Grant and Gale suggested the possible identity of
Macoma moliniana Dall (1048) from Coos Bay, Oregon,
with M. indentata. The species described by Dall has a
strong posterior flexure but the shape of the pallial sinus
is quite different from that on the corresponding valve of
M. indentata. Weaver (1049) compared M. moliniana with
M. nasuta and cited it as occurring in beds of Oligocene
age.

Macoma indentata has been reported from beds of
Pliocene age in the Los Angeles basin, in San Joaquin Val-
ley, in the Santa Maria district, as well as at Coos Bay,
Oregon, and elsewhere.

Simonova (1050) reported M. indentata as occurr-
ing in late Tertiary beds on Sakhalin Island but we have
not seen specimens from there.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Macoma (Rexithaerus) indentata tenuirostris Dall
Plate 41, Figure 15; Plate 50, Figure 7
Plate 52, Figure 2

Macoma (indentata Carpenter, var.?) tenuirostris Dall,
Proc. U. S. Nat. Mus., Vol. 23, No. 1210, p. 324, Nov-
ember 14, 1900. P. 309, as ““Macoma (Rexithaerus) in-
dentata var. tenuirostris Dall.”

Macoma identata tenuirostris Dall, Johnson and Snook,
Seashore Animals of the Pacific Coast (Macmillan Co.:
New York), ed. 1935, p. 451, fig. 443. “‘Santa Bar-
bara Islands to San Diego (Kelsey).” Recent.

Type specimen. — No. 73469, United States Nat-
ional Museum.

Type locality. — “‘San Pedro, California.” (Dall.)

Range. — Middle Pliocene to Recent. Recent from
Santa Barbara, California, to Ensenada, Lower California,
Mexico, in 91 to 137 meters (50 to 75 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305, 305A,
331.

Original description. — “‘This form differs from the
typical indentata in being more elongated, with a shorter
and more pointed posterior end and deeper flexure.”
(Dall, p. 309.)

“For the rostrate form, pending the acquisition of
more and fresh material, I would propose the varietal
name of tenuirostris. It measures: lon. 55, alt. 33, and
diam. 16 mm. The nearest specimen of the typical form
measures respectively 44, 31 and 12 mm. The beaks are
25 mm_ behind the anterior end and in tenuirostris 33
mm behind it. The left valve is notably flatter than the
other in the type [M. indentata], while in the only pair
we have of the variety the valves, though flexuous, hardly
differ in degree of convexity.” (Dall, p. 324.)

Remarks. — Macoma indentata tenuirostris is here
reported from the San Diego Formation for the first time.
A right valve (the posterior end incomplete), is 40 mm
long and 28 mm high. Faustman (1051) illustrated a
fossil that is probably this subspecies, from the Rio Dell
Formation of Pliocene age in Humboldt Co., California.
It also has been reported from beds of late Pleistocene
age in the Newport Bay (1052) area in southern Calif-
ornia.

Some authors (1053) have considered this sub-
species to be without taxonomic significance. We have ex-
amined six Recent right valves from San Diego in the Hen-
ry Hemphill collection of the California Academy of
Sciences. The largest one is 55 mm long and 33.5 mm
high, the beak is 31 mm from the anterior end. The pos-
terior end is rostrate and pointed. These differ from typi-
cal M. indentata in the shell characters enumerated by
Dall.

Fossil specimens in the present collection, 25 to 30
mm in length appear to be comparatively longer in out-
line than do adult forms.

Macoma copelandi Wiedey (Trans. San Diego Soc.
Nat. Hist., Vol. 5, No. 10, p. 149, pl. 19, fig. 2, March 31,
1928) described from the Temblor Formation in San
Luis Obispo Co., is less attenuated posteriorly and more
inflated anteriorly in comparison to M. i. tenuirostris Dall.

GENUS FLORIMETIS OLSSON AND HARBISON

Florimetis Olsson and Harbison, Acad. Nat. Sci. Phil-

297

adelphia, Mon. 8, p. 129, November 6, 1953. “Type
herewith designated: Tellina intastriata Say. Recent,
Florida.” — Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 410,
1961. Type as designated by Olsson and Harbison.

Type species (by original designation, Olsson and
Harbison, 1953): — Tellina intastriata Say [Jour. Acad.
Nat. Sci. Philadelphia, Vol. 5, Pt. 2, p. 218, February,
1826. “Coast of East Florida.” Illustrated by Olsson and
Harbison, 1953, p. 129, pl. 15, figs. 1, 1a, 1b. Key West,
Florida, Recent. — Afshar, Geol. Soc. Amer., Mem. 119,
p. 92, pl. 39, figs. 1-5, 1969 (as Apolymetis (Florimetis)
intastriata.) Florida. |

Range.—Late Oligocene to Recent. Recent in warm
temperate and tropical waters, from the littoral zone to
46 meters (25 fathoms).

Original description. — Shell broadly subovate, in-
equivalve with a wide, depressed, or wing-like posterior
area, which in the right valve is set-off by an angled keel
extending from the beak to the posterior extremity. Both
valves are strongly convex along the anterior umbonal
slope, the right valve being impressed just behind it or a-
cross the middle. Interior shows the adductor scars plainly
marked in the adult, the anterior scar being narrow, elon-
gated or lucinoid, with the pallial line attached to its hin-
der end, posterior scar rounded and placed quite low.
Pallial sinus deep, reaching nearly to the anterior adduc-
tor scar and confluent below with the pallial line by more
than half its length. Hinge with small cardinal teeth, the
left anterior and the right posterior being bifid, no lat-
erals. Ligament strong, external, the resilium portion
forming the larger part of the scar. Exterior white or
colorless, the surface sculpture smoothish or of finely
crowded growth lines, much heavier on the posterior
wings. (Olsson and Harbison.)

Remarks. — The species in the present paper re-
ferred to the genus Florimetis has been cited in earlier
literature under the generic names Metis (1054), Poly-
metis (1055), and Apolymetis Salisbury (1056).

Olsson and Harbison, and later Keen, pointed out
that the west American species referred to Apolymetis
are quite different from the East Indian species, Tellina
meyeri, the type species of that genus. The outline of the
type species of Florimetis is subquadrate, the posterior
flexure very well developed, the anterior end is rather in-
flated and the posterior portion is sculptured with rather
coarse concentric lines of growth. This is quite different
from the oval outline and fine, regular concentric lines of
growth on Tellina meyeri.

Olsson and Harbison recognized Florimetis as a sub-
genus of Hemimetis Thiele (1057), and Keen placed it as a
subgenus of Psammotreta Dall (1058). Olsson, 1961, gave
Florimetis generic status and we follow this practice, at
least until there is general agreement concerning the nom-
enclature of the supraspecific units of the Tellinidae.

Weaver and Kleinpell recently reported a species un-
der the name of “‘Apolymetis cf. A. sespeensis (Loel and
Corey)” (1059) from strata believed to be of Oligocene
age. That species was originally described under the genus
Macoma and the illustration by Weaver and Kleinpell
bears a general resemblance to some species of Macoma,
such as Macoma constricta Bruguiere (1060). The fossil is
not referable to Florimetis s. s. Weaver and Kleinpell men-
tioned that Poromya teglandae Weaver, 1942, and Apol-

298

ymetis twinensis Durham are synonymous with Macoma
sespeensis Loel and Corey, 1932.

“Metis” rostellata Clark and “Metis” vancouver-
ensis Clark and Arnold were described from strata assigned
an Oligocene age.

Florimetis biangulata Carpenter
Plate 53, Figures 14, 17, 19

T[ellina]. alta Conrad, Jour. Acad. Nat. Sci. Philadelphia,
Vol. 7, Pt. 2, p. 258, 1837. “Inhabits coast of Calif-
ornia, near Sta. Barbara.”

Not Tellina alta Conrad, Fossil Shells of the Tertiary For-
mations of North America (reprint by G. D. Harris,
1893), Vol. 1, no. 4, p. 41 (67), October, 1833.

2Scrobicularia biangulata Carpenter, Proc. Zool. Soc. Lon-
don for 1855, p. 230, February 5, 1856.

Arcopagia medialis Conrad, Proc. Acad. Nat. Sci. Phil-
adelphia, Vol. 8, p. 314, December, 1856 [1857].
“Monterey Co., Cal.”’ “Middle Tertiary.”” — Conrad, U.
S. Pac. Railroad Expl., Vol. 6, Pt. 2, No. 2, p. 70, pl.
2, fig. 6, 1857.

Arcopagia unda Conrad, U. S. Pac. Railroad Expl., Vol. 7,
p. 192, pl. 4, figs. 3, 4, 1857. “Shore of Santa Barbara
county, California.” Miocene.

Metis alta Conrad, Arnold, Mem. Calif. Acad. Sci., Vol. 3,
p. 160, 1903. ‘Pliocene at Pacific Beach.””— Arnold,
U. S. G. S., Prof. Paper 47, p. 28, 1906. “San Diego
Formation as developed in the type section at Pacific
Beach, north of San Deigo. . .”, Pliocene. — J. P. Smith,
Proc. Calif. Acad. Sci., Ser. 4, Vol. 3, pp. 172, 181
1912. “San Diego-Purisima.”’ — J. P. Smith, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 9, No. 4, p. 151, 1919. “San
Diego” Pliocene. — I. S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 169, pl. 57, fig. 3,
1924. Pliocene to Recent. — Hertlein, Stanford Univ.
Bull., Ser. 5, No. 78, p. 84, 1929. “San~ Diego
Pliocene.”

Apolymetis biangulata Carpenter, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 363, pl. 20, fig. 16
(Barlow Canyon, Pleistocene), 1931. ‘Pliocene of Pacif-
ic Beach, San Diego (Arnold 1903).” — Durham,
Geol. Soc. Amer., Mem. 43, Pt. 2, p. 89, pl. 24, fig. 1;
pl. 25, fig. 12, 1950. ‘“‘Miocene (?) to Recent.” — Fitch,
State Calif. Dept. Fish Game, Mar. Fish. Branch, Fish
Bull. No. 90, p. 72, fig. 38, 1953. “‘Point Conception,
California, to San Quentin, Baja California,” Recent. —
K. V. W. Palmer, Geol. Soc. Amer., Mem. 76, p. 107, pl.
14, fig. 5, 1958. (Carpenter’s original description; type
specimen illustrated.)

Florimetis biangulata Carpenter, Moore, San Diego Soc.
Nat. Hist., Occas. Paper 15, p. 64, pl. 30, figs. a, b,
1968. San Diego, Pleistocene. Also “Pliocene at Pacif-
ic Beach.”

Type specimen. — No. 61.5.20.117, British Mus-
eum (Natural History).
Type locality (of Scrobicularia biangulata). — ““Hab.

Sta. Barbara; legit. T. Nuttall, Esq. Museo suo.”

Range. — ? Early Miocene (Vaqueros and Temblor).

Late Miocene to Recent. Recent, Point Conception, Calif-

ornia, to San Quintin Bay, Lower California, Mexico,

from littoral zone to 46 meters (25 fathoms); often along
the outer coast in coarse sand and gravel or near boulders.
Occurrence in San Diego Fm. — C.A.S. 12, 114.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

L.A.M. 305. U.C.L.A. 312.

Original description of ?Scrobicularia biangulata. —?
S. t. suborbiculari, subaequilaterali, convexiscula, striis
concentricis vix regularibus, postice undata, angulis duo-
bus subobsoletis; ligamento externo tenuissimo, in sulcos
alte impresso, semi-interne sito; ligamento intermo fossa
trigonali scalena sito, alteri adjacente; dentibus cardinali-
bus in utraque valve duobus, contiguis, vix radiantibus;
cicatricibus muscularibus subovalibus, sinu palii maximo;
alba, intus aureo tincta. Long. 1.5, lat. 1.78, alt. .8 poll.
(Carpenter.)

Remarks. — A specimen of this species collected by
Henry Hemphill in the San Diego Formaton is approx-
imately 71 mm long, 55mm high and the convexity (both
valves together), 30.5 mm. Three single valves, the largest
one about 60 mm long, were collected near the Mexican
boundary by George P. Kanakoff.

This large, suborbicular tellinid attains a length of
about 83 mm. It can be readily recognized by the well de-
veloped posterior fold, and anterior to this a shallow but
pronounced submedian concavity extends from near the
umbos to the ventral margin of the right valve. The hinge
of each valve has two teeth, the right posterior and the
left anterior ones the larger. On a Recent specimen 72.4
mm long the pallial sinus extends forward 52 mm and
joins the pallial line 36 mm from the posterior end of the
shell.

The longer ligamental area, wider hinge plate, and
higher cardinal teeth are features which serve to separate
Florimetis biangulata from the tropical west American
species, F. cognata Pilsbry and Vanatta (1061) of which
F. clarki Durham (1062) is a variety. Florimetis cognata
often has been recorded in the literature under the name
of ‘Metis’ excavata Sowerby (1063), a species with a
wedge-shaped posterior end and described without infor-
mation as to the locality from which it came. Study of
the hinges of F. biangulata and F. cognata led Durham to
doubt the reported occurrences of the former in beds of
Miocene age. It also is quite possible that various records
of the occurrence of F. biangulata in subtropical west
American waters may be questionable. It has been re-
corded in beds of Pliocene age at various localities in the
San Joaquin Valley and in southern California but not in
the northern part of the state. However, it does occur in
beds of Pleistocene age at Tomales Bay, Loc. 563 (CAS),
in central California.

Dall (Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 5, p.
1044, 1900) pointed out that a poorly preserved fossil
from Santa Barbara Co. described by Conrad in 1857 as
Arcopagia unda, is probably identical with the present
species.

Khomenko (1064) recorded the occurrence of
“Metis alta’ in the late Tertiary of Kamtschatka but the
identity of that form with the present species needs
confirmation.

Keen (1065) recently stated that two species (1066)
described from the Orient in 1855, Tellina turgida Des-
hayes from ‘“‘Catbalonga, Philippines,” and Tellina obesa
Deshayes from “China Seas,” are probably identical with
Scrobicularia biangulata Carpenter. She gave reasons for
preferring usage of the name Tellina obesa rather than T.
turgida if the Internatl. Comm. on Zool. Nomencel. should
rule that the species name proposed by Carpenter should
be replaced by one of the earlier names of Deshayes.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

FAMILY SEMELIDAE STOLICZKA (1067)

Description.—Shell round or ovate in outline, valves
gently convex, the posterior end with an obscure fold; res-
ilium internal, resilifer elongate and nearly parallel to the
hinge; hinge with two cardinal teeth, and usually with lat-
erals; pallial sinus long and wide. Eocene to Recent.

Remarks. — The internal resilium serves to separate
this family from the Tellinidae in which the resilium is
external.

Yonge (1068) discussed the structure and adapta-
tion of members of this family, most of which live on
sandy bottoms and have long siphons.

Key to genera of Semelidae

A. Pallial sinus free from the

pallial line . Semele
B. _Pallial sinus confluent with the
pallial line . Cumingia

GENUS SEMELE SCHUMACHER

Semele Schumacher, Eassai Nouv. Syst. Vers. Test., p. 165,
pl. 18, fig. 2, 1817. Sole species, Tellina reticulata
Spengler. — Lamy, Jour. de Conchyl., Vol. 61, No. 3, p.
314, 1914. “dont le type est S. reticulata Sow. =S.
proficua Pult.”’ — Grant and Gale, Mem. San Diego Soc.
Nat. Hist., Vol. 1, p. 875, 1931. “Type (by mono-
typy), Tellina reticulata Spengler = Tellina proficua Pul-
teney; Caribbean; Recent.”

Type species (by monotypy and by original des-
ignation). — Tellina reticulata Spengler [Skrift. Nat. Selsk.,
Vol. 4, Heft 2, p. 115, 1798.] [= Tellina proficua Pul-
teney, Catalogues of the Birds, Shells, . . .Plants, . . .Doret-
shire, p. 29, pl. 5, fig. 4 (as T. reticulata), 1799. ‘‘On the
sands at the North shore, Poole, and at Weymouth.”
[Locality erroneous. This species lives along the coast of
southeastern United States and in the West Indies.] Illus-
trated (hinge) by Lamy, 1914, p. 315, also illustrated by L.
Perry, Bull. Amer. Paleo., Vol. 26, No. 95, p. 77, pl. 16,
fig. 103, 1940. Southwest Florida in 3 to 6 fathoms. Con-
cerning T. proficua see Bowden and Heppell (Jour. Conch.
Vol. 26, No. 5, pp. 324, 328, 1969)].

Range. — Eocene to Recent. Recent chiefly in warm
temperate and tropical waters. From the littoral zone to
about 112 meters (61 fathoms), perhaps deeper.

Description. — Shell oval or suborbicular, slightly
inequivalve, usually more or less rostrate posteriorly. Um-
bones subcentral, low, proximate, prosogyrate. Ligament
short, external; resilium strong, internal. Hinge armature
of 2 cardinals and 2 laterals in each valve, the laterals of
the right valve usually stronger. | Adductor impressions
large, semielliptical. Pallial sinus profound. (Gardner, J.,
U.S. G. S., Prof. Paper 199, p. 100, 1948.)

Remarks. — Five species of Semele have been re-
ported from the Tertiary of California. Another one is
here recorded for the first time from the San Diego For-
mation. Over thirty species now live in tropical and sub-
tropical waters of the western Americas.

Lamy (1069) published a summary of the species
of this genus represented in the collections of the Natural
History Museum in Paris. Dall (1070) published notes on
the west American species of Semele and more recently
Hertlein and Strong (1071) discussed and illustrated a
number of species from this region, as have Keen (1072),
and Olsson (1073).

Key to Species of Semele

A. Concentric rugae rounded, sometimes nearly
obsolete; a small, narrow, depressed

lunular area present rubropicta
B. Concentric rugae flat-topped, regular;

depressed lunular area slight

or lacking ashleyi

Semele ashleyi n. sp.
Plate 48, Figures 3, 4, 6, 9, 10

Semele ef. S. rubropicta Dall, Woodring, in Woodring and
Bramlette, U. S. G. S., Prof. Paper 222, p. 88, pl. 14,
fig. 12, 1950. ‘““Foxen mudstone at the Waldorf asphalt
mine, in the Cebada member of the Careaga sandstone
at Fugler Point and locality 177, and may be present
in diatomaceous strata of the Sisquoc formation.”
Santa Maria district, southern California.

Type specimens. — Holotype and paratypes in Los
Angeles County Museum, Department of Invertebrate
Paleontology.

Type locality. — Loc. 305C (LAM), exposure at
hill, 100 feet west and 440 feet south of the northeast
corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base
and Meridian (see U. S. G. S. topog. map, San Ysidro
quad., rev. 1953).

Range. — Middle Pliocene.

Occurrence in San Diego Fm. — L.A.M. 305, 305C,
318.

Description. — Shell elongately ovate, the posterior
end shorter, the posterior ventral margin faintly trun-
cated, the general outline and shell characters similar to
those of Semele rubropicta. Sculpture consists of rather
coarse, slightly flattened, concentric ridges which increase,
in width with growth of the shell, these are separated by
incised grooves which are about one third to one fourth
the width of the ridges; both ridges and grooves are crossed
by fine, shallow, irregularly spaced radial lines, most
readily observable on slightly eroded specimens; hinge of
right valve with an anterior cardinal, a central cardinal
followed by ligamental area, an anterior and a posterior
lateral are present, left valve with a thick anterior cardinal,
followed by a thin central cardinal and a resilial pit, an
anterior and a posterior lateral are present; pallial sinus
broad, slightly ascending, the end broadly rounded and
faintly ellipsoid at the distal portion. Dimensions of
holotype; length 40.5 mm, height 37 mm convexity (both
valves together) 23.6 mm, pallial sinus extends anteriorly
28.5 mm from the posterior end of the valve.

Remarks. — The holotype, single valves, and several
fragments of this new species, in the collections of the
Los Angeles County Museum from near the Mexican
boundary, were available for study.

This species appears to be identical with the one

300

illustrated by Woodring (1050) as “‘Semele ef. S. rub-
ropicta Dall” from strata of Pliocene age in the Santa
Maria district in Santa Barbara Co., California.

The concentric ridges of Semele ashleyi n. sp. are
coarser and are separated by wider and more deeply in-
cised grooves than those on S. rubropicta. Also the lun-
ular area beneath the beaks of S. ashleyi is only slightly
depressed whereas on S. rubropicta there is a small but
well developed, narrow, depressed lunular area (see plate
48, figure 7).

One lot of Recent specimens, 3 paired valves, the
largest 30.5 mm long, and several small single valves of a
Semele in the collections of the California Academy of
Sciences collected by Henry Hemphill from roots of kelp
in deep water off San Diego, California, closely resemble
the fossil form here described from the San Diego For-
mation. The chief differences noticed in comparison of
this lot of Recent specimens with specimens of the new
species of comparative size, are that the ribbing on the
umbos of the Recent shells becomes coarser at an earlier
stage of growth and the depressed lunular area is com-
paratively larger than it is on S. rubropicta.

A small right valve from Loc. 305 (LAM) illus-
trated on Plate 48, Figures 4 and 8, is probably a juvenile
form of S. ashleyi n. sp.

This new species is named for Dr. George H. Ash-
ley, author of an important paper (1895) dealing with
the Pliocene of central California.

Semele rubropicta Dall
Plate 48, Figures 1, 2, 7, 11

Semele rubropicta Dall, Amer. Jour. Conch., Vol. 7, Pt.
2, p. 144, pl. 14, fig. 10, November 2, 1971. ‘‘Habitat.
Beach as Soquel, Monterey Bay, two or three valves,
Dall; San Pedro, Cooper; Neah Bay, one worn valve,
Swan.” — Arnold, U. S. G. S., Bull. 396, pp. 31, 156,
pl. 25, fig. 3, 1909. ‘Upper Etchegoin formation.”
— I. S. Oldroyd, Publ. Puget Sound Biol. Sta. Vol. 4,
p. 56, pl. 22, fig. 10, 1924. [Copy of original figure. ]
Off San Juan and Lopez Islands, Washington, also
other locs. — I. S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 180, pl. 43, fig. 10,
1924. [Copy of original figure.] “Forrester Island,
Alaska, to Tia Juana, Lower California.”’ — Dall, Proc.
U. S. Nat. Mus., Vol. 66, Art. 17, p. 26, pl. 18, figs. 1,
2, 1925. “Beach at Soquel, Monterey Bay, Calif.””—
Johnson and Snook, Seashore Anim. Pac Coast (Mac-
millan Co.: New York), ed. 1935, p. 453, fig. 448. Al-
aska to Lower California. — Stewart, in Woodring, Ste-
wart and Richards, U. S. G. S., Prof. Paper 195, p. 33,
list opp. p. 38 and list opp. p. 78, pl. 11, fig. 18, 1940
[1941] (as Semele cf. S. rubropicta). — Abbott, Amer.
Seashells (D. Van Nostrand Co.: New York, London,
Toronto,) p. 435, pl. 29, fig. W., 1954. “Alaska to
Mexico.”

Type specimen. — No. 101960, United States Nat-
ional Museum.

Type locality. — “Beach at Soquel, Monterey Bay,
Calif.” (Dall, 1925.)
Range. — Early Pliocene (Jacalitos) to Recent. Re-

cent from Forrester Island, Alaska, to Tijuana, Lower
California, Mexico, in 37 to 91 meters (20 to 50 fathoms).

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Occurrence in San Diego Fm. — L.A.M. 305, 305C,
318.

Original description. — Shell usually pure white and
brilliantly polished within, but occasionally with a faint
yellowish or pinkish flush when very deeply colored ex-
ternally. Inner margin, except on the hinge-line, always
pure white. Outside, covered with a thin yellowish green
or olive, epidermis usually wanting, color yellowish white,
with rose-pink and pure white rays, color stronger on the
lines of growth. Sculpture consisting of incised lines rad-
iating from the umbones where they become obsolete;
crossed by rounded, smooth, concentric ridges rather
sharply defined by concentric grooves. These ridges are
usually regular but sometimes bifurcating. In perfect spec-
imens the radiating lines and grooves are so sharp that
their intersections appear as if punctured. Ligament pit
deep and excavated, cardinal and lateral teeth moderate.
Anterior end much produced, rounded, margin rounded
below, posterior end very short, almost truncated; shell
rather inflated. Lunule deeply impressed, narrow, lanceo-
late, short. General form subquadrate. Umbones incon-
spicuous, usually tinged with yellow. Hinge-line below the
lunule with a purple spot. Interior marked with extremely
faint radiating lines. Posterior portion of the inferior mar-
gin produced. Shell thick and solid. Alt. 1.35 in. Lon.
1.55 in. Diam. .7 in. Lunule .24 in. (Dall.)

Remarks. — A well preserved specimen from Loc.
305C, (L.A.M.), is 42.8 mm long, 36 mm high, convexity
(both valves together) 22 mm and a right valve from the
same locality, the ventral portion incomplete, is 47.5 mm
long. One fairly well preserved right valve, 45.6 mm long
and 39 mm high, is present in the collection from Loc. 318
(LAM). A number of fragments and small valves also are
present at Loc. 305 (LAM) near the Mexican boundary.
The sculpture on these fossils varies as it does on Recent
specimens.

The largest Recent specimen in the collections of the
California Academy of Sciences, from Puget Sound, is
50.5 mm long, 41.8 mm high, convexity (both valves to-
gether), 24.8 mm, the broadly rounded pallial sinus ex-
tends anteriorly 31.5 mm from the posterior end of the
valves.

Sculpture in this species varies from specimen to
specimen and sometimes varies on the two valves of the
same specimen. The concentric sculpture may be very
fine or fairly coarse and fairly regular to irregularly
spaced. Some Recent shells bear deep concentric grooves
at intervals of from 3 mm to 10 mm on some specimens
in the collections of the California Academy of Sciences,
the umbonal area is nearly smooth. The shells of this
species in the northern portion of their range are relat-
ively smooth whereas those in more southern waters tend
to develop concentric rugae.

Semele fausta Nomland (Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 10, No. 4, p. 233, pl. 9, figs. 3, 3a, 3b,
April 19, 1917) described from Etchegoin beds of Plio-
cene age in middle California, differs from S. rubropicta
in the more posteriorly situated beaks and in other de-
tails.

GENUS CUMINGIA SOWERBY

Cumingia Sowerby, Proc. Zool. Soc. London for 1833, p.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

34, May 17, 1833. Four species cited including Cum-
ingia lamellosa Sowerby. — Dall, Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 5, p. 998, 1900. “Type C. mutica
Sby.” — Olsson, Mollusks of the Tropical Eastern Pac-
ific (Paleo. Res. Inst.: Ithaca, New York), p. 370,
1961. Type as designated by Gray, 1847.

Type species (by subsequent designation, Gray,
Proc. Zool. Soc. London for 1847, p. 187). — “C. lam-
ellosa”’ [Cumingia lamellosa Sowerby, 1833, p. 34. ‘‘Hab.
prope littora Oceani Pacifici.” ‘“‘Found at Payta in hard

clay at low water; and at Panama in deep water.’’ — Sow-
erby, Reeve’s Conch. Icon., Vol. 19, Cumingia, species 5,
pl. 1, fig. 5, 1873. “Hab. Chili.”” — Olsson, 1961, p. 371,

pl. 66, figs. 10, 10a; pl. 67, figs. 3, 3a, 1961. Gulf of
California to northern Peru].

Range. — Miocene to Recent. Recent in the west-
ern Americas from Crescent City, California, to Chile,
nestling in holes bored by mollusks or in crevices in rocks,
piling, gravel, etc., from the intertidal zone to 46 meters
(25 fathoms). Also Japan and western Atlantic, from the
littoral zone to 91 meters (50 fathoms).

Description. — Shell often distorted but normally
equivalve, inequilateral, anteriorly rounded, posteriorly
subtruncated and _ slightly gaping; lunule small and
escutcheon larger in left valve; sculpture principally con-
centric, formed by elevated ridges, their interspaces
minutely striated or sagrinated; ligament partially ex-
ternal and internal, the external ligament small and over-
lies a large posteriorly directed chondrophore or resilifer
developed equally in both valves; anterior side of resilifer
bordered by a small cardinal tooth and socket; right valve
with two strong lateral teeth bordered above by sockets
into which fit the thickened margins of the other valve;
pallial sinus large, confluent below with the pallial line.
(Adapted from H. and A. Adams, Gen. Rec. Moll., Vol. 2.
p. 412, 1858, and Olsson and Harbison, Acad. Nat. Sci.,
Philadelphia, Monogr. No. 8, p. 135, 1953.)

Remarks.—The genus Cumingia was recorded doubt-
fully from the San Diego Formation by Dall and the pre-
sent record is based upon fragments retaining portions of
the hinge. This genus has been reported from Pliocene to
Recent in western North America but in eastern North
America it is known to occur in beds of Miocene age. A
species was described as ‘“‘Cumingia?antiquata”’ (1074) by
Philippi from beds of Tertiary age in Chile but an in-
spection of the illustration convinces us that the generic
assignment is doubtful. Von Ihering (1075) stated that
Cumingia does not occur in beds of Tertiary age in Pat-
agonia

Cumingia? keittensis Harris was described from
strata of Kocene age in Alabama but the generic assign-
ment remains open to question.

The genus Cumingia is represented in strata of
Pliocene and Pleistocene age in California by but one
species which also lives in adjacent waters. One species,
C. densilineata Dall, was described from beds of Pleis-
tocene age at San Quintin, Lower California. Several Re-
cent species have been described from more southern wat-
ers but it is apparent that there are too many names for
the species represented. However, at least three species
live in the region between California and Chile.

Dall (1900, p. 999) pointed out that on both the
Pacific and Atlantic coasts of the United States, the spec-
ies in the northern part of their ranges are larger, the

301

sculpture is more regular and less sparse, whereas in the
southern part of their ranges, the shells diminish in aver-
age size and concentric lamellae become relatively more
prominent. The shell of Cumingia is variable in shape and
sculpture as a result of the animal’s habit of nestling in
holes and crevices.

The soft parts of Cumingia were described by Des-
hayes (1076), and Grave (1077) discussed the natural
history of C. tellinoides.

The Recent species of Cumingia in the Natural His-
tory Museum in Paris were discussed by Lamy (1078).

Stoliczka, 1871, placed Cumingia in a subfamily
cuminginae.

Cumingia cf. C. californica Conrad

The following references refer to typical Cumingia
californica. C.[umingia] californica Conrad, Jour. Acad.
Nat. Sci. Philadelphia, Vol. 7, Pt. 2, p. 234, pl. 17, fig.
12, 1837. — Dall, Proc. U. S. Nat. Mus., Vol. 1, p. 11,
1878. ‘“‘Later Tertiary” of San Diego. Also Recent. —
Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 5, p.
1001, 1900. ‘“‘Pliocene of San Diego?; Hemphill.’’ —
Arnold, Smithsonian Mise. Coll. (Quart. Issue), Vol.
50, Pt. 4, p. 445, pl. 56, fig. 5, 1907. ‘Fugler Point
asphalt mine, near Gary,” California, Pliocene. Also
Recent. — Arnold, U. S. G. S., Bull. 322, pp. 58,
148, pl. 23, fig. 5, 1907 (1908). Some records as in
preceding reference. — J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 3, pp. 171, 181, 1912. “San Diego-
Purisima,” Pliocene. — Lamy, Jour. de Conchyl., Vol.
61, No. 3, 1914. “‘San Diego,” Recent. — Abbott,
American Seashells. (Van Nostrand Co.; New York),
p. 436, pl. 31, fig. V, 1954. “‘Crescent City, California,
to Chile.”

Type specimen. — Location of the type specimen
unknown to the present authors.

Type locality. — ‘“Ynhabits with the above; rare.”
[The above is Sphenia californica from “Inhabits salt
marshes, near Sta. Barbara; rare.’’]

Range.—Pliocene (Jacalitos) to Recent. Recent from
Crescent City to San Martin Island, Lower California,
Mexico, from the intertidal zone to 46 meters (25 fat-
homs), in holes bored by mollusks and in crevices in
rocks, piling, and in gravel.

Occurrence in San Diego Fm. — L.A.M. 305.

Original description. — Shell triangular, convex,
thick, with numerous irregular lamellar concentric striae;
posterior side compressed, cuneiform; beaks central, ra-
ther prominent; lateral teeth prominent. Length, one inch
and one-fourth. (Conrad.)

Remarks. — The present record of Cumingia cali-
fornica in the San Diego Formation is based upon three
fragments, of which one left valve retains a part of the
hinge with most of the chondrophere and a small tooth
anterior to it. An occurrence of Cumingia californica in
strata of Pliocene age at San Diego would not be out of
place because it has been reported from beds of Pliocene
age in San Joaquin Valley and in the Cebada Member of
the Careaga Formation in the Santa Maria district along
with other species which likewise occur in the San
Diego beds.

Strong (1079) pointed out that Cumingia california

302

at times has been confused with more southern species,
especially C. lamellosa Sowerby (1080). The latter spec-
ies is only about a fourth the size of C. californica and is
more triangular in outline. Cumingia lamellosa Sowerby
is a different species from the one described as Thyella
lamellosa H. Adams (1081) (=C. elegans Sowerby) from
the East Indian Archipelago and Australia, a species
placed at times by some authors in the genus Cumingia.

A large specimen of Cumingia californica in the
Academy’s collection, taken at San Diego by Henry
Hemphill, is 30.1 mm long, 22.8 mm high, the convexity
(both valves together) 11.8 mm, the pallial sinus extends
forward 20 mm from the posterior end of the valve and
joins the pallial line after a short bend posteriorly. The
hinge of the right valve has a lateral tooth on each side
and the left valve has a small cardinal tooth in front of
the ligamental pit. A weak lateral or extension of the
margin on each side fits into sockets in the opposite
valve.

The shell of this species is often distorted because
of the animal’s habit of nestling in crevices in rocks and
other objects.

FAMILY DONACIDAE FLEMING

The shell is generally transversely trigonal to cunei-
form, equivalve, solid in texture, with entire or crenulated
and usually closed margins. The surface is smooth or with
fine radial lineation or riblets. The ligament is external,
short, usually opisthodetic, and attached to and along a
nymphal plate. Pallial line distinct, placed a short space a-
bove the margin, its sinus short or of medium length, gen-
erally directed horizontally, its end well rounded. The
adductor scars are subequal in size and often deeply im-
pressed. Substance of the shell is usually coarse, por-
cellaneous, white externally or grading into violet or
purple, the same coloration in the interior. (Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 336, 1961.) Late Cre-
taceous to Recent.

Remarks. — An account of the structure and adap-
tation of the shells of this family of mollusks was pub-
lished by Yonge (1082) and Chavan (1083) discussed the
systematic position of members of this family. Many of
the Recent tropical west American species were discussed
by Hertlein and Strong (1084), by Keen (1085), and by
Olsson (1086).

GENUS DONAX LINNAEUS

Donax Linnaeus, Syst. Nat., ed. 10, p. 682, 1758. Donax
rugosa Linnaeus included in original list of species. —
Romer, Syst. Conchyl. - Cab. von Martini und Chem-
nitz, Bd. 10, Abt. 3, p. 4, 1871.—Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 378, 1931.
Type (as designated by Herrmannsen): ‘““Donax rugo-
sus’’ Linnaeus.—Dodge, Bull. Amer. Mus. Nat. Hist.,
Vol. 100, Art. 1, p. 77, 1952. Type (as designated by
Schumacher): Donax rugosus Linnaeus.

Type species (designated by Schumacher, Essai

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Nouv. Syst. Vers Test., p. 144, 1817.) — “Donax rugosa
Lin.” Ref. to “Pl. XIII. fig. 4. Chemn. 6, pag. 254. Tab.
25. fig. 250.” This species also was designated as the type
species of Donax (of Lamarck) by Schmidt, Versuch
Conchyl. - Samml., pp. 55, 176, 1818; also designated as
type by Herrmannsen, Indic. Gen. Malac., Vol. 1, p. 404,
1847, and by Gray, Proc. Zool. Soc. London for 1847, p.
187. [|Donax rugosa Linnaeus, Syst. Nat., ed. 10, p.682,
1758. “Habitat in O. meridionali.”” Ref. to Gualtieri,
Test., pl. 89, fig. D. Illustrated by Reeve, Conch. Icon.,
Vol. 8, Donax, sp. 9, pl. 2, figs. 9a, 9b, 9c, 1854. “Hab.
Gold Coast, West Africa.”—Nicklés, Moll. Test. Mar. Cote
Occid. d’Afrique. Man. Ouest - Africains, Vol. 2, p. 211,
fig. 405 (p. 212), 1950. See also Dodge, 1952, p. 80.]

Range. — Eocene to Recent. Recent, world wide in
warm temperate and tropical waters, from between tides
to about 82 meters (45 fathoms), on sand.

Description. — Shell moderately small, elongate-trig-
onal to subcylindrical in outline, closed; beaks prosogy-
rous, posterior to subcentral; anterior end produced and
rounded, posterior end short, sometimes truncated; scul-
pture consists of fine radial riblets, sometimes punctate;
ligament external; hinge usually with two cardinals in
each valve, one commonly bifid, laterals variable; pallial
sinus deep, horizontal, partly confluent with pallial line
ventrally; margins usually crenulated.

Remarks.—Donax apparently is not known to occur
earlier than Eocene time. Notodonax Ferruglio (1087)
was described from beds of late Cretaceous age in Argen-
tina and Protodonax Vokes (1088) was described from
strata of late Cretaceous age in Wyoming.

At the present time, about one hundred species of
Donax live in very shallow, warm temperate and tropical
marine waters. The northern range of this genus along
the coast of California is about 35° 10’ 00’ N.

{Donax californicus Conrad]

Df[onax]. californica Conrad, Jour. Acad. Nat. Sci.
Philadelphia, Vol. 7, Pt. 2, p. 254, pl. 19, fig. 21,
1837.—Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 5, p. 968, December, 1900. “Pliocene of San
Diego, California, Well.”

Donax flexuosus Gould, Cooper, Calif. State Min. Bur.,
Seventh Ann. Rept. State Mineral., p. 238, 1888.
“Pl. — San Diego Well.”

Not Donax flexuosus Gould, 1853 = D. striata
1767. See Dall, 1900, p. 968.

Type specimen. — Twelve syntypes, No. 61.5.20.91,
British Museum (Natural History) (A. M. Keen, Veliger,
Vol. 8, No. 3, p. 170, 1966.)

Type locality. — “Inhabits the coast of California in
sand, near Sta. Barbara.”

Range. — Pleistocene to Recent. Recent, Goleta,
California, to Magdalena Bay, Lower California, Mexico.
“Found in sand or sandy mud of bays, lagoons and es-
tuaries and other localities not exposed to the pounding
surf.” (Fitch).

Occurrence in San Diego Fm. — San Diego well
(Cooper; Dall).

Remarks. — This species was recorded by both Coop-
er and Dall as occurring among the fossils from the San

Linnaeus,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Diego well. We have not seen specimens of it in any col-
lections from the San Diego Formation. It occurs com-
monly in Pleistocene beds in southern California and
northern Lower California. It has not been recorded
from strata of Pliocene age, so far as we know, by any
modern author.

The shell of Donax californicus differs from that of
D. gracilis Hanley (1089), an inhabitant of tropical and
subtropical west American waters, in that it is less elon-
gated and the posterior dorsal margin slopes more steeply
ventrally.

Recent specimens of Donax californicus Conrad
were illustrated by Hertlein and Strong (1949, pl. 1, figs.
2, 5) and by Fitch (1090).

SUBGENUS SERRULA CHEMNITZ

Serrula Chemnitz, Morch, Cat. Conchyl. Yoldi, Pt. 2, p.
18, 1853. Several species cited including Donax trun-
culus Linnaeus.—Grant and Gale, Mem. San Diego Soc.
Nat. Hist., Vol. 1, p. 379, 1931. “Type (by subsequent
designation, Dall, 1900), D. trunculus Linnaeus.”

Type species (designated by von Martens, Zool.
Rec., Vol. 7, Moll., p. 172, 1870). — “‘Type trunculus, L.”
[Illustrated by Bucquoy, Dautzenberg, and Dollfus, Moll.
Mar. Roussillon, Vol. 2, Fasc. 9 (Pelecypoda, Fase. 22),
p. 454, pl. 68, figs. 1, 2, 3, 4, 1893. European seas. For a
discussion of this species see Dodge, Bull. Amer. Mus.
Nat. Hist. Vol. 100, Art. 1, pp. 80-81, 1952.]

Range. — Pliocene to Recent.

Description. — Shell oval-triangular, cuneiform,
gibbous in front; margins denticulated within; hinge with
oblong cartilage fissure. (Tryon, 1884.)

Remarks. — The subgeneric assignment of some of
the west American Cenozoic species of Donax is not en-
tirely satisfactory. However, the following species from
the San Diego Formation appears to be better placed in
Serrula than in any other supraspecifie group.

Donax (Serrula) gouldii Dall
Plate 48, Figures 16, 19; Plate 57, Figure 8

Donax obesus Gould, Proc. Boston Soc. Nat. Hist., Vol. 4,
p. 90, November, 1851. — Gould, Boston Jour. Nat.
Hist., Vol. 6, p. 394, pl. 15, fig. 9, 1853. ‘‘Inhabits San
Diego.”

Donax obesus Philippi, Zeitschr. f. Malakozool., Jahrg. 8,
No. 5, p. 75, 1851. ‘Patria: California ex auct. merca-
toris, a quo emi.”

Not Donax obesus d’Orbigny, Voy. Amér. Mérid., Vol. 5,
Moll., p. 541, pl. 81, figs. 28, 30, 1846. “Elle a été pe-
chée a Payta (Pérou) par M. Fontaine.”

Donax gouldii Dall, U. S. Nat. Mus., Bull. 112, p. 49, Feb-
ruary 24, 1921. ‘‘Santa Barbara, California, to Acapul-
co.” Recent. [New name for Donax obesus Gould
1851, not Donax obesus d’Orbigny, 1846.] — I. S.
Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 183, pl. 49, figs. 8, 9, 1924. “‘Range. Santa
Barbara, California, to Acapulco, Mexico.”’ (On expl.
to pl. 49, as Donax gouldi.) — Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 380, pl. 13, fig.

303

12, 1931. Pleistocene to Recent.

Donax gouldi Dall, Fitch, State Calif. Dept. Fish Game,
Mar. Fish. Branch, Fish Bull. No. 90, p. 84, fig. 50,
1953. “Range: Pismo Beach, California, to Cape San
Lucas, Baja, California.”

Type specimen. — Location of type specimen
unknown to the present authors.
Type locality. — “San Diego” [California.]

Range. — Middle Pliocene to Recent. Recent from
San Luis Obispo, California, to Todos Santos Bay, Lower
California, in intertidal zone, on sandy beaches.

Occurrence in San Diego Fm. — L.A.M. 319.
U.C.L.A. 294, 311.

Original description (of Donax obesus Gould). — T.
parva, solida, ovatocuneata, ventricosa, nitida, radiatim
leviter striata, coloribus albidis et fulvidis omnino vel ra-
diatiim picta et plerumque zonis violaceis ornata; angulo
postero-dorsali rectangulari; facie posteriori cordiformi,
subtriangulari; latere antico angustato, citO rotundato;
margine ventrali denticulato, postice coarctato: intus alba,
vel flavescens, violaceo nuberculata, ad marginem dor-
salem fuscata. Long. 9/10, alt. 6/10; lat. 4/10 poll.
(Gould.)

Remarks. — Ten single valves of Donax gouldii are
present in the collections of the University of California
at Los Angeles from near the Mexican boundary. The
largest, a left valve, is 19.4 mm in length. Three valves in
fairly good state of preservation, the largest one about 20
mm long, and three fragments are present in the collec-
tion of the Los Angeles Museum from Loc. 319 (LAM)
near the Mexican boundary. The present specimens are
comparable to Recent valves of similar size. A large Re-
cent specimen collected by Henry Hemphill at San Diego
is 24.6 mm long, 15.3 mm high, convexity (both valves
together) 11 mm.

This species is represented in the collections from
the San Diego Formation by a comparatively small num-
ber of valves. Fitch, 1953, mentioned that at times, bil-
lions of living individuals of this species form a solid pave-
ment several layers deep in the sandy beaches in south-
ern California.

Coe (1091) discussed the ecology of Donax gouldii
and more recently Pohlo (Veliger, Vol. 9, No. 3, pp. 330-
337, figs. 1-5, 1967) discussed aspects of the biology of
this species.

FAMILY GARIDAE STOLICZKA

The shell is telliniform, donaciform, or soleniform,
usually equivalve and if unequal, the right valve is the
larger and more convex, usually with a gap at the post-
erior end. The surface is often highly colored in which
shades of red, pink, and purple predominate, spread uni-
formly or in a streaked, maculated, or rayed pattern;
The hinge has one or two, bifid or grooved cardinal teeth;
there are no laterals. The ligament is external, large, lies
entirely posterior of the beaks and is attached to a large,
nymphal plate which rises prominently above the hinge
margin. The adductor scars are distinct, placed rather
high dorsally and connected by a pallial line bearing a
deep sinus. The periostracum is usually coarse and dark
in color in some groups, thin and inconspicuous in

304

others. (Olsson, Mollusks of the Tropical Eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), p. 347, 1961, for
Family Sanguinolariidae.) Cretaceous to Recent.

Remarks. — The shells of this family resemble
those of the Tellinidae but the posterior end is usually
less twisted and the valves more gaping, the hinge plate
is broader as are the nymphs back of the beaks and the
valves are covered with a thicker periostracum.

The species in this family are more numerous in
warm waters; about ten or twelve species distributed in
five genera have been reported occurring in tropical and
subtropical west American waters.

Dall (1093) published a synopsis of the Cenozoic
““Psammobiidae” of North America.

Key to Genera of Garidae

A. Sculpture of posterior area
differentiated from that

on remainder of shell . Gari s. s. (1904)

B. Sculpture on posterior area
not differentiated from that

on remainder of shell . . Gobraeus

GENUS GOBRAEUS LEACH

Gobraeus Leach, manuscript name in Brown, Recent
Conch. Great Britain and Ireland, edit. 2, p. 102,
1844 (as “‘Gobraeus vespertinus, Leach, MSS.” in the
synonymy of Psammobia vespertina, p. 102,-pl. 40,
fig 3). —Leach, Synop. Moll. Gt. Britain, p. 265, 1852.
Species cited: ‘Gobraeus variabilis” in the synonymy
of which are, Tellina depressa [refs. to Pennant and
Dillwyn], Tellina variabilis [refs. to Pulteney and to
Donovan]. Solen vespertinus [refs. to Bruguiere, Wood,
and others]. From various localities around Great Brit-
ain. — K. V. W. Palmer, Geol. Soc. Amer. Mem. 76,
p. 111, 1958. “Type species by monotypy G. variabilis
Leach=Solen vespertinus Gmelin, 1791.’ — Olsson, Mol-
lusks of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 356, 1961. Type species same
as cited by Palmer.

Type species (by monotypy; and by subsequent de-
signation by Dall, Proc. Acad. Nat. Sci. Philadelphia, Vol.
50, p. 57, 1898). — “Type Psammobia vespertina Lam.
European Seas.” [=Solen vespertinus Gmelin, Linn.
Syst. Nat., ed. 13, Vol. 1, Pars VI, p. 3228, 1791. ‘‘Hab-
itat in mari mediterraneo& Atlantico.”’ Illustrated by Wood,
Gen. Conch., p. 135, pl. 33, figs. 2, 3, 1835. Mediterra-
nean, Atlantic, and various localities around Great Britain.
Also, Reeve, Conch. Icon., Vol. 10, Psammobia, species
17, pl. 10, fig. 17, 1865. ‘“‘Hab. Mediterranean.” See also
Bucquoy, Dautzenberg, and Dollfus, Moll. Mar. Roussillon,
Tom. 2, Fase. 10 (Pelecypoda, Fasc. 23), p. 485, pl. 71,
figs. 1-7, 1895 (as Psammobia depressa Pennant, fig. 1
(typical), fig. 2 (var. livida Jeffreys), figs. 3, 4 (var. nor-
malis Bucquoy, Dautzenberg, and Dollfus), figs. 5, 6, 7

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

(var. caerulescens Réquien). |

Range. — Eocene to Recent. Recent from the inter-
tidal zone to 73 meters (40 fathoms), in sand.

Description. — Shell inflated, more or less truncate
behind; concentrically striate or nearly smooth, often
with fine radial striae, especially evident on the posterior
dorsal region; teeth variable, not more than three in the
right valve and two in the left valve; sinus rounded in
front, rarely shorter than the vertical of the beaks, and
often more or less detached from the pallial line. ( Dall.)

Remarks. — The shell of Gobraeus differs from that
of Gari in that the posterior dorsal area lacks any differ-
entiation of sculpture from the remainder of the shell
other than a coarsening of the concentric threads. The
surface of the shells of this genus are often rayed with
lilac and purple tints. The valves gape posteriorly.

In recent years, west American species, such as the
one referred to the genus Gobraeus in the present paper,
have been assigned to the genus GariSchumacher (1095).
There have been differences of opinion concerning the
identification of the type species of Gari as revealed in
discussions by Stewart (1096), Dodge (1097), Cox (1098),
and others.

Schumacher referred to figures 92 and 93 shown
on plate 10 by Chemnitz (Neue Syst. Conchyl. — Cab.,
1782) and more recently Lemche and Parker (1199) pub-
lished an illustration of the specimen shown in Chemnitz’s
figure 93 which was said to have come from Nicobar.

Recently, the Internatl. Comm. on Zool. Nomencl.
designated Gari vulgaris Schumacher, 1817, as type spec-
ies of Gari, as defined by a lectotype selected by Lemche.
This species appears to be identical with Solen amethystus
Wood, 1815 (1101).

The concentric threads on the type species are off-
set along a groove or line on the posterior area. This in-
terpretation of the type species of Gari results in the rele-
gation of all west American species of this group to the
genus Gobraeus.

Psammobia Lamarck (1102) has been placed in the
synonymy of Gari by some authors. Keen recently ass-
igned it subgeneric rank under Gari.

Mesozoic (1103) species have been referred to
‘“Psammobia”. However, according to Gardner (1104)
that genus is not known with certainty to occur in the
Cretaceous but it was well established by mid-Eocene
time. Finlay and Marwick (1105) mentioned that Gari
first appeared in New Zealand in the Bortonian, late
Eocene.

Davies (1106) pointed out that on many species of
“Gari” of Eocene age, the pallial sinus is rather short and
free from the pallial line whereas on typical species the
pallial sinus is longer and is confluent with the pallial line.

The genus Gobraeus is represented by but one spe-
cies in the fauna of the San Diego Formation. At the pre-
sent time three species occur in the waters off California
and five species have been recorded occurring in tropical
and subtropical west American waters. The west Ameri-
can species of Gobraeus usually burrow in sand or sandy
mud to a depth of several centimeters. Yonge (1107) dis-
cussed the structure and adaptation of British species re-
ferred to “Gari’’ and mentioned that they are especially
adapted to inhabit substrata of coarse sand or shell and
gravel.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Gobraeus endentulus Gabb
Plate 48, Figures 13, 15

2S[iliquaria]. edentula Gabb, Geol. Surv. Calif., Palaeo.,
Vole2a poss pleas figs di. 869°

Psammobia edentula Gabb, J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 3, pp. 174, 182, 1912. “San Diego-
Purisima.”” Lower Pliocene. — I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 185, pl. 57,
fig. 1, 1924. Pliocene to Recent.

Psammobia (Gobraeus) edentula Gabb, Dall, Proc. U. S.
Nat. Mus., Vol. 66, Art. 17, p. 23, pl. 19, fig. 1, 1925.
“San Pedro, Calif.: Recent specimen.”

Gari edentula Gabb, Stewart, Acad. Nat. Sci. Philadelphia,
Spec. Publ. No. 3, p. 281, pl. 13, fig. 3, August 9,
1930. “Horizon, Pliocene; locality, San Fernando.”
[Lectotype discussed and illustrated.] — Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 382,
pl. 21, fig. 5 (San Pedro, California, Recent), 1931.
Late Miocene to Recent. — Fitch, Calif. State Dept.
Fish Game, Mar. Fish. Branch, Fish Bull. No. 90, p.
80, fig. 46, 1953. Santa Barbara, California, to San
Diego, California, Recent.

Gari (Psammocola) edentula Gabb, Korobkov, Spravoch-
nik I Metodicheskoe Rukovodstvo po_ tretichnym

Molluskam Plastinchatozhabernye [ Lamellibranchiata } .

Gostoptehizdat [Publishing house], Leningrad, pl. 16,
fig. 2 [copy of figure from Grant and Gale], 1954.
Type specimen. — Lectotype No. 15035, Academy

of Natural Sciences of Philadelphia.

Type locality. — ‘“‘From the Pliocene of San Fer-
nando,” California.

Range. — Middle Miocene (Temblor, Loel and Cor-
ey), to Recent. Recent from Santa Barbara to San Diego,
California, in 6 to 24 meters (3 to 13 fathoms), in the
more quiet sheltered waters along the outer coast where
this species is believed to burrow to a depth of five or six
inches (Fitch).

Occurrence in San Diego Fm.
L.A.M. 178A, 305, 305A, 319.
U.C.L.A. 294, 312, 2359.

Original description. — Shell moderately large, thin,
flattened, elongated sub-elliptical,
beaks minute, a little posterior to the middle, projecting
almost insensibly beyond the cardinal line; cardinal mar-
gin sloping slightly and perfectly straight towards the two
ends; anterior end convexly and very obliquely subtrun-
cate above, produced and rounded below; posterior end
broadly and regularly rounded, a little less prominent be-
low than above the middle; basal margin nearly straight.
Surface nearly smooth in the middle, marked by pretty
distinct lines of growth towards the ends, especially
above. Length from beak to base, 1.3 inch; width, 2.6
inch; beak to anterior end, 1.45 inch. (Gabb.)

Remarks. — Several specimens, fairly well preserved,
in the collections from the San Diego Formation, are sim-
ilar to Recent specimens of Gobraeus edentula. The larg-
est specimen, from Loc. 4(SD) south slope of Mount
Soledad is 87 mm long, 42.8 mm high, the convexity
(both valves together), 17.3 mm. Recent specimens at-
tain a length of about 125 mm. Many fragments from
the San Diego Formation in the collections of the Los
Angeles County Museum are referable to this species.

=a Or Acs. i209.
S.D. 2, 4, 331, 365.

nearly equilateral;

305

The hinge has two cardinal teeth in each valve,
those of the left weaker, especially the posterior one
which may be reduced to a lamina. Both teeth slope gent-
ly posteriorly, the posterior one the more so. There is
variation in the size of the teeth in a series of specimens.
In some the left anterior tooth is about half its usual
height and is flattened on the distal surface.

The pallial sinus extends forward more than one
half the length of the shell. On a Recent specimen 125
mm long the pallial sinus extends forward 70 mm and
joins the pallial line at about 63 mm from the posterior
end of the shell.

The more elongate and more compressed valves
sculptured with fine even concentric threads are features
which readily serve to separate the present species from
Gobraeus californicus Conrad, a well known species which
has been reported to range from San Diego, California, to
Japan.

A fossil cited as ““Psammobia, aff. edentula (Gabb)”’’,
was reported by Clark (1108) from the San Ramon For-
mation which he considered to be of Oligocene age. The
preservation of the fossil is so imperfect that identifica-
tion of the species is uncertain.

The nomenclature of the present species may be in-
volved with that of the earlier Tellina fucata Hinds (1109)
which was described from Magdelena Bay, Lower Calif-
ornia.

FAMILY SOLECURTIDAE D’ORBIGNY

Shell inequivalve, elongated, gaping at both ends.
Ligament external. Hinge with or without diverging teeth.
(Translation of d’Orbigny, Voy. dans Amér. Meérid., Vol.
5, Moll., p. 522, 1846). Late Cretaceous to Recent, in
temperate and tropical seas.

Remarks. — This family is separated from the Sole-
nidae chiefly on the basis of anatomical characters. These
characters, were given by d’Orbigny as follows: ‘Animal
muni d’un manteau fermé plus ou moins, ayant une ouver-
ture buccale par ou sort un pied volumineux comprimé. A
la région anale se trouvent deux tubes distincts et separés,
plusieurs muscles a chaque valve.”

Ghosh (1110) gave a detailed description of the soft
parts of some members of this family.

GENUS TAGELUS GRAY

Siliquaria Schumacher, Essai Nouv. Syst. Vers Test., p.
129, 1817. Species cited, Siliquaria notata Schumac-
er, pl. 7, figs. 2, 3, in synonymy of which are Solen
gibbus Spengler, Solen guineensis Chemnitz, Solen
Tagal, Adanson.

Not Siliquaria Bruguiere, Tabl. Encyclop. Méthod. (Vers),
Vol. 1, p. XV, 1789. No species cited.] See also Des-
hayes, Encyclop. Méthod., Vol. 3, p. 950, 1832.

Tagelus Gray, Proc. Zool. Soc. London for 1847, p. 189,
November, 1847. “‘Sol. guinensis”’ indicated as type.—
Gardner, U.S.G.S., Prof. Paper 199, p. 107, 1948.
“Type by original designation: Solen guineensis guin-
ensis Chemnitz = Solen gibbus Spengler.” — Olsson
Mollusks of the Tropical Eastern Pacific (Paleo. Res.

306

Inst.: Ithaca, New York), p. 350, 1961. “Type species
by original designation: Solen guineensis (=Solen gib-
bus Spengler).”

Type species (by original designation). — “Sol.
guineensis” [=Solen guineensis W. Wood, Gen. Conch., p.
129, 1815, “Inhabits the coast of Guinea.” Ref. to
Chemnitz, Syst. Conch.-Cab., Bd. 11, pl. 198, fig. 1937,
1795. “bey der Guineischen Kiiste wohnet.’—Also illus-
strated by Reeve, Conch. Icon., Vol. 19, Solecurtus,
species 21, pl. 4, figs. 21a, 21b, 1874 (as Solen caribaeus).
“Hab. America.’ ]

Range. — Late Oligocene or early Miocene (1111)
to Recent. Recent in warm temperate and tropical wat-
ers, intertidal zone to 73 meters (40 fathoms).

Description. — Shell with elongated, solen-like
valves but with the beaks near the middle, the length be-
tween three and four times the height. The anterior side
is generally a little fuller, the posterior side often slight-
ly depressed especially near its dorsal margin. Both ends
of the valves are rounded and generally with a wide open
gap. Hinge weak with two small cardinal teeth in the
right valve and only one in the left; there are no lat-
erals. The ligament is external and attached to a high
nymphal plate. Adductor scars large, placed close to the
dorsal margin, and connected across by the pallial line
bearing a large open sinus. There is sometimes a slight
flexure across the middle of the valves, the surface
marked with lines of growth only, white or colored
faintly with violet or brown, sometimes rayed. The per-
iostracum is dark brown or straw-colored, generally
coarsely wrinkled. (Olsson, 1961.)

Remarks.—Only two species of Tagelus have been
reported from beds of Tertiary age in California, one of
which occurs in the San Diego Formation. Ten Recent
species have been described from eastern Pacific waters
between Monterey, California, and Puerto Montt, Chile.

Hesse (1112) mentioned that many Recent species
of Tagelus are confined to brackish or estuarine waters.
Other species, however, including many fossils are assoc-
iated with strictly marine forms.

The anatomy of some of the Recent species was
described by Bloomer (1113).

Subtagelus Ghosh (1114), is a synonym of Mes-
opleura Conrad, with the same type species, Solen divi-
sus Spengler. Ghosh believed that this group possessed
more primitive anatomical characters than Tagelus S.s.

Keen (1145) placed the genus Tagelus in the fam-
ily Solecurtidae rather than in the Garidae (Psammob-
iidae).

SUBGENUS TAGELUS S&S. S.
Tagelus (Tagelus) californianus Conrad

Sfolecurtus]. californianus Conrad, Jour. Acad. Nat.
Sci. Philadelphia, Vol. 7, Pt. 2, p. 233, pl. 18, fig. 3,
1837.—Dall, Proc. Calif. Acad. Sci., Vol. 5, p. 296,
1874. ‘‘Well at San Diego,” “‘Pliocene.”—Dall, Proc.
U.S. Nat. Mus., Vol. 1, p. 28, 1878. “well-digging in
stratum B2,” San Diego.—Cooper, Calif. State Min.
Bur., Seventh Ann. Rept. State Mineral., p. 265, 1888.
“Pl.—San Diego well.’”’—Orcutt, West Amer. Sci., Vol.
6, whole No. 46, p. 85, August, 1889. Dall’s record

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

(1874) cited.—Orcutt, cited by Ellis in Ellis and Lee,
U.S.G.S., Water Supply Paper 446, p. 59, 1919. Dall’s
record (1874) cited.

Tagelus californianus Conrad, Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 169, 1903. “‘Pliocene.—San Diego
(Dall).”—I.S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 186, 1924. ‘‘Pliocene at San
Diego.” Also Recent.—Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 384, pl. 21, figs. 2a,
2b, 3 (San Pedro Pleistocene), 1931. Dall’s record
(1874) cited—Hertlein and Grant, Mem. San Diego
Soc. Nat. Hist., Vol. 2, Pt. 1, p. 48, 1944. Dall’s re-
cord (1874) cited.—Fitch, State Calif. Dept. Fish
Game, Mar. Fish. Branch, Fish Bull., No. 90, p. 79,
fig. 45, 1953. Various localitites cited. Recent.

Tagelus (Tagelus) californianus Conrad, Moore, San Diego
Soc. Nat. Hist., Occas. Paper 15, p. 68, pl. 32, fig. a
(Pleistocene in San Diego), 1968. ‘Pliocene in Balboa
Park,’”’ San Diego.

Type specimen. — Syntype No. 54.3.14.55, British
Museum (Natural History) (see A.M. Keen, Veliger, Vol.
8, No. 3, p. 171, 1966).

Type locality.—‘‘Inhabits muddy salt marshes, in
the neighbourhood of Sta. Barbara; common.”

Range. — Pliocene to Recent. Recent from Mon-
terey, California, to the Gulf of California and south to
Corinto, Nicaragua, possibly to Panama (1116). In bays,
estuaries and sloughs, on mud flats or in sandy mud,
burrowing to a depth of 42 em (20 inches) (Fitch).

Occurrence in San Diego Fm. — San Diego well
(Dall). Balboa Park (Moore). L.A.M. 305A.

Original description. — Shell oblong-oval, rather
thin, convex; extremities equally rounded; basal margin
slightly contracted in the middle; beaks central; colour
white, tinged with yellowish brown, and marked with di-
rect brown lines in the middle of the valve; epidermis
straw colour with radiating wrinkles on the posterior
slope. Length, 3 and a half inches. (Conrad.)

Remarks. — This species was reported among the
fossils from the San Diego well by Dall in 1874. A frag-
ment of the umbonal portion of a left valve, 10 mm long,
from Loc. 305 A (LAM), near the Mexican boundary, is
here referred to Tagelus californianus. The hinge and a
small muscle impression near the dorsal margin are com-
parable to the corresponding characters of Recent speci-
mens of T. californianus.

A large Recent specimen in the collection of the
California Academy of Sciences collected by Henry
Hemphill at San Diego, is 112 mm long, 31.5 mm high,
convexity (both valves together) 20 mm, the pallial sin-
us extends anteriorly 50 mm from the posterior end of
the shell. A specimen collected by E. P. Chace (1117) at
Puertecitos, in the Gulf of California, is 128 mm long.
The ciliary mechanism of the present species was des-
cribed by Kellog (1118).

Tagelus californianus often occurs on mud flats in
estuaries and sloughs. Orcutt (1119) reported this spe-
cies at Salton Sea, along with freshwater shells, but speci-
mens of Tagelus derived from strata in that area (1120)
which we have seen are more nearly referable to T. affinis
longisinuatus Pilsbry and Lowe.

Tagelus californianus was reported by Reagan (1121)
to occur in the Quillayute Formation of Pliocene age
in western Washington, but Dall (1112) later examined

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

the specimen, a fragment, and stated that it was referable
to the genus Tagelus but he could not identify it specifi-
cally.

Tagelus clarki Loel and Corey (1123), described
from strata of early Miocene age in California, is shorter
and more ovate in outline, the valves are more convex
and the posterior dorsal concavity and the umbonal
ridge are more pronounced than those of T. californianus.

SUPERFAMILY SOLENACEA GRAY (1124)
FAMILY SOLENIDAE GRAY (1125)

Shells usually elongate, sword or razor-shaped,
equivalve, usually open and truncated at both ends.
Beaks low, terminal or somewhat distant from the ant-
erior umbones, larger in those species having the um-
bones more distant from the end, the adductor scars
large and well marked. Hinge relatively weak with one or
two small cardinal teeth, more or less projecting, the lig-
ament external and attached to a short nymph. Surface
smooth or sculptured with concentric lines of growth,
sometimes with oblique striae or groovings, covered by a
coarse brown or straw-colored periostracum. Hinge plate
often strengthened or buttressed by a thickened ray.
Burrowers in sand. (Olsson, A.A., Mollusks of the Tropi-
cal Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
p. 419, 1961.). Late cretaceous to Recent.

Remarks. — Three genera of this family are re-
presented by fossil forms in the San Diego Formation.

A synopsis of the Solenidae of North America by
Dall (1126) appeared in 1899. Recently Habe (1127)
published a paper dealing with the Solenidae of Japan.
Yonge discussed evolution within the Solenidae (Univ.
Calif. Publ. Zool., Vol. 55, No. 9, pp. 421-438, figs. 1-8,
1951).

Key to Genera of Solenidae

A. Beaks terminal or nearly so
a. Left valve with one

cardinal tooth. . Solen
aa.Left valve with two
cardinal teeth Ensis
B. Beaks subcentral or
nearly so . Siliqua

GENUS SOLEN LINNAEUS

Solen Linnaeus, Syst. Nat., ed. 10, p. 672, 1758. Solen
vagina included in list of species.—Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 385, 1931.
Type (designated by Children): Solen vagina Linn-
aeus.—Eames, Philos. Trans. Roy. Soc. London, Ser.
B, Biol. Sci., No. 627, Vol. 235, p. 432, 1951. “‘Type
species. Solen vagina Linné, Recent = S. brevis Gray;
Children, 1822.’—Olsson, Mollusks of the Tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),

307

p. 420, 1961. “Type species by subsequent designa-
tion, Lamarck, 1799 or by Schumacher, 1817, Solen
vagina Linné.”

Type species (designated by Schumacher, Essai
Nou. Syst. Test., p. 124, pl. 6, fig. 3, 1817).— Solen
vagina Linnaeus [Syst. Nat., ed. 10, p. 672, 1758, ‘‘Hab-
itat in M. europaeo, Indico.” Schumacher cited a refer-
ence to “Pl. VI. fig. 3, Chemn. 6 pag. 40. Tab. 4. fig. 28.”
According to Chemnitz the specimen represented in this
figure “Sie wohnet in den ostindischen Meeren.” Child-
ren (Quart. Jour. Sci. Lit. Art, Vol. 14, p. 83, pl. 4,
fig. 26, October, 1823) also designated Solen vagina
Linnaeus as type of Solen. Hanley (Ipsa Linn. Conch., p.
29, 1855) believed that this species was an East Indian
form illustrated by Mawe (Linn. Syst. Conchyl., pl. 5,
fig. 2, 1823) and this was accepted by Stewart (Acad.
Nat. Sci. Philadelphia, Spec. Publ. No. 3, p. 289, 1930).
Hedley (Proc. Linn. Soc. New South Wales, Vol. 38, Pt.
2, p. 275, 1913) believed Solen vagina to be a common
species of north Queensland which included among its
synonyms, S. truncatus Mawe S. brevis Gray, S. fonesii
Dunker and S. jonesii Conrad. Dodge (Bull. Amer. Mus.
Nat. Hist., Vol. 100, Art. 1, p. 45, 1952) recently dis-
cussed this species and was convinced that the species
name Solen vagina is applicable to the Recent European
shell. The latter was illustrated by Sowerby in Reeve’s
Conch. Icon., Vol. 19, Solen, species 2, pl. 1, fig. 2,
1874. “Hab. Great Britain.’”’ Also Tryon, Struct. and
Syst. Conch., Vol. 3, p. 129, pl. 106, fig. 6, 1884.]

Range. — Eocene to Recent. Recent from the
intertidal zone to 400 meters (219 fathoms).

Description. — Shell long, straight, dorsal and ven-
tral margins parallel, ovate in cross-section, ends gaping;
beaks terminal or usually decidedly anterior; surface
smooth; hinge with one tooth in each valve; ligament
long, external; anterior muscle impression elongated,
posterior one subovate; pallial line extends beyond ad-
ductors; sinus short, rather square.

Remarks. — Members of this genus all have long,
narrow shells, and the animal burrows in sand or sandy
mud to depths of 50 cm at an angel of about 60°. Most
of the species live in shallow water.

Two species of Solen occur in Californian waters
and six species have been recorded occurring in tropical
and subtropical west American waters. Eleven or twelve
species have been reported from strata of Tertiary age in
the western United States. Eight species of this genus
have been reported living in Japanese waters by Habe.
(1128).

Key to Species of Solen

A. Dorsal margin straight; very
narrow in proportion to

length . rosaceus
B. Dorsal margin slightly arcuate;

moderately broad in proportion

to length sicarius

308

Solen rosaceus Carpenter
Plate 48, Figure 12

Solen sicarius ? var. rosaceus Carpenter, Rept. Brit. Assoc.
Adv. Sci. for 1863, pp. 536, 638, August, 1864. Re-
print in Smithsonian Mise. Coll., No. 252, pp. 22, 124,
1872.—Carpenter, Ann. Mag. Nat. Hist., Ser. 3, Vol.
15, p. 177, 1865. Reprint in Smithsonian Misc. Coll.,
No. 252, p. 279, 1872.

Solen rosaceus Carpenter, Dall, Proc. Calif. Acad. Sci.,
Vol. 5, p. 296, 1874. “Well at San Diego.”—Cooper,
Calif. State Min. Bur., Seventh Ann. Rept. State Min-
eral., p. 265, 1888. ‘San Diego well.”—Orcutt, West
Amer. Sci., Vol. 6, whole No. 46, p. 85, August, 1889.
Dall’s record (1874) cited.—Arnold, Mem. Calif. Acad.
Sci., Vol. 3, p. 171, 1903. ‘‘San Diego well (Cooper).”
—Orcutt, cited by Ellis in Ellis and Lee, U.S.G.S.,
Water Supply Paper 446, p. 59, 1919. Dall’s record
(1874) cited—Weymouth, State Calif. Fish Game
Comm., Fish Bull. No. 4, p. 50, pl. 15, fig. 3, 1920.
San Diego, California, Recent. — I. S. Oldroyd, Stan-
ford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 188,
1924. [Not pl. 49, fig. 6] “San Diego well.”—Hert-
lein and Grant, Mem. San Diego Soc. Nat. Hist., Vol
2, Pt. 1, p. 48, 1944. Dall’s record (1874) of San
Diego well.—Fitch, Calif. State Dept. Fish Game, Mar.
Fish. Branch, Fish Bull. No. 90, p. 76, fig. 42, 1953.
“Humboldt Bay, California, to Mazatlan, Mexico.”
[Not the record “Humboldt Bay, California.” ]—K.V.
W. Palmer, Geol. Soc. Amer., Mem. 76, p. 114, 1958.
[Discussion of Carpenter’s specimens.]—Pohlo, Vel-
iger, Vol. 6, No. 2, pp. 98, 100 figs. 1, 2, 4, 1963.
{Morphology and mode of burrowing. |

Type specimen.—‘‘The type of this species has not
been found.” (Palmer. 1958.)

Type locality. — Cited as from “neighborhood of
Sta. Barbara” and “The region between S. Diego and S.
Pedro,” California (Carpenter, 1864). “Hab. Sta. Bar-
bara (Jewett; S. Pedro (Cooper)” (Carpenter, 1865).
“Santa Barbara or San Pedro, California (type)’’ (Pal-
mer, 1958).

Range. — Pliocene to Recent. Recent, from Santa
Barbara, California, to Punta Pensaco and San Felipe in
the Gulf of California and south to Mazatlan, Sinaloa,
Mexico. Intertidal zone to 46 meters (25 fathoms).
“Usually found at depths from a few inches to a foot or
more in sandy mud of sheltered bays, sloughs and es-
tuaries” (Fitch).

Occurrence in San Diego Fm. — San Diego well
(Dall). C.A.S. 1182. S.D. 5006.

Original description. — Straight, narrower, longer,
smaller; glossy, rosy. (Carpenter, 1864.)

Supplementary description. — S. testa S. sicario
simili, sed minore; multo angustiore, elongata, recta, ex-
tus et intus rosacea; epidermide tenui, valde nitente.
Long. .27, lat. .5, alt. .32 poll. (Carpenter, 1865.)

Remarks. — A cast of a small Solen collected at

Loc. 4, (SD), on Mount Soledad, was identified as S.

rosaceus by Mrs. Kate Stephens. The posterior end is
lacking but the remainder is 29.2 mm long and 7.3 mm
high. Another less perfectly preserved cast from the
Loc. 1181 (CAS), also from Mount Soledad, is 21 mm
long. The straight dorsal margin and the ratio of height

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

to length of both casts are comparable to Recent speci-
mens of S. rosaceus. A portion of a cast, 15 mm long,
collected at Loc. 34 (SD), northeast corner of India and
Thorn streets, San Diego, may be referable to this
species.

The shell of Solen rosaceus differs from that of S.
sicarius Gould in that it is longer in proportion to the
height and also in that the dorsal margin is straight
rather than distinctly arcuate in outline.

Recent shells of S. rosaceus have rosy coloration
rather than white as in Gould’s species. Large specimens
are often about 70 mm long. Johnson and Snook men-
tioned a very large specimen 75 mm long, 14 mm high
and 19 mm in diameter.

It appears probable that records of this species
from Miocene strata are referable to Solen perrini Clark.
That species has a straight dorsal margin but has a thicker
shell which also is much higher in proportion to the
length than that of S. rosaceus. Clark’s species was con-
sidered by Grant and Gale to be a subspecies of S.
sicarius.

Solen tanozawaensis Nomura (1129) described from
Miocene strata in Japan was compared by its author with
S. rosaceus from which it differs in the more arcuate dor-
sal margin.

Weymouth (1920) mentioned concerning S. ros-
aceus, “‘it is interesting as being capable of a kind of
‘swimming’ though habitually found in burrows.”

Solen sicarius Gould
Plate 49, Figure 7

Solen sicarius Gould, Proc. Boston Soc. Nat. Hist., Vol. 3,
p. 214, May, 1850. — Gould, U. S. Explor. Exped.
(Wilkes), Vol. 12, p. 387, 1852, Atlas, p. 13, pl. 33,
figs. 501, 501a, 501b, 1856. — Reagan, Trans. Kansas
Acad. Sci., Vol. 22, p. 204, 1909. Quillayute For-
mation, western Washington, Pliocene. Also ‘‘Purisima
San Diego.”’—J.P.Smith, Proc. Calif. Acad. Sci., Ser. 4,
Vol. 3, pp. 174, 182, 1912. “San Diego - Purisima.”” —
Packard, Univ. Calif. Publ. Zool., Vol. 14, No. 2, p.
281, pl. 26, fig. 1, pl. 50 (chart), 1918. ““Range. —
Vancouver Island to San Quentin, Lower California
(Orcutt).”—Weymouth, State Calif. Fish Game Comm..,
Fish Bull. No. 4, p. 50, pl. 15, fig. 2, 1920. British
Columbia to Southern California, Recent. — I. S. Old-
royd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol.
1, p. 188, pl. 49, fig. 1; pl. 18, fig. 1, 1924. Various
localities, Pliocene to Recent. — Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 385, pl. 21, fig. 4,
1931. Late Miocene to Recent. — Fitch, State Calif.
Dept. Fish Game, Mar. Fish. Branch, Fish Bull. No.
90, p. 77, fig. 43, 1953. “Range: British Columbia to
San Quintin Bay, Baja California.”

Type specimen. — Holotype No. 11876, United

States National Museum.

Type locality. — ‘‘Hab. Straits of De Fuca, Oregon.”

[ Washington. |

Range. — Late Miocene (Briones; Santa Margarita;

San Pablo) to Recent. Recent from Vancouver Island,

British Columbia, to San Quintin Bay, Lower California,

Mexico; littoral zone to 124 meters (68 fathoms), burrow-

ing in mud or muddy sand to a depth of 15 to 20 inches

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

in bays, estuaries and sloughs.

Occurrence in San Diego Fm. — C.A.S. 1181, 1402,
28891. L.A.M. 305, 305A, 319. S.D. 4, 417.

Original description. — T. transversa, oblonga, ret-
rorsum angustata, subfalcata, epidermide crasso, nitido,
corneo induta, antice obliqué truncata, posticé rotundata:
valvis valde excavatis, undulatis, areis triangularibus indis-
tincté partitis; margine dorsali recto; m. ventrali arcuato;
natibus terminalibus: cardo dente triangulari, erecto,
recurvo in utraque valva instructa. Long. 3 1/2; lat. 7/20;
alt. 9/10 poll. (Gould.)

Remarks. — One of the best preserved specimens of
this species in the collections from the San Diego Forma-
tion, lacking only small portions of the ventral area, is
one in the San Diego Society of Natural History from the
south slope of Mount Soledad. It is 62.2 mm long, 14.9
mm high, the convexity (both valves together) 10.4 mm.
This and other specimens from Balboa Park, in all ob-
served characters, resemble Recent specimens of Solen
sicarius. Large Recent specimens from adjacent waters
attain a length of 75 mm and a height of 18 mm and
specimens 88 mm long have been reported from Morro
Bay, California. Fragments of this species are present
from several localities near the Mexican boundary.

The shell of this species differs from that of Solen
rosaceus in the larger size, gently arcuate rather than
straight dorsal margin and on Recent specimens the color
is greyish rather than rose.

Solen perrini Clark (1130), described from strata
of late Miocene age, has a straight dorsal margin similar to
that of S. rosaceus, but the flexure on the anterior end is
more pronounced than on S. sicarius. This form is said to
attain a length of 153 to 204 mm (six to eight inches)
and a height of 25 to 38 mm (1 to 1 1/2 inches).

Solen clallamensis Clark and Arnold (1031) des-
cribed from beds of middle Miocene age at Clallam Bay,
Washington, bears a similarity to S. sicarius but it was said
to differ in the more rounded anterior end and in that the
anterior sulcus is situated farther from the end of the
shell.

Small specimens about 40 mm in length from the
Eugene Formation in western Oregon, believed to be of
Oligocene age, were referred to S. sicarius by Hickman
(1132).

“Solen cf. siscarius Gould” was cited as occurring in
Formosa by Kuroda (1133), but apparently there is doubt
concerning the identification because Kuroda and Habe
(1134) include it with question in a check list of Japanese
species. The general shape of S. krusensterni Schrench as
illustrated by Hirase (1135) is similar to that of S.
sicarius.

The record of Solen sicarius from a Quaternary terr-
ace in Ecuador (1136) is referable to some other species.

GENUS ENSIS SCHUMACHER

Ensis Schumacher, Essai nouv. Syst. Hab. Vers Testacés,
p. 143, 1817. Species cited, ‘“Ensis magnus” [Schu-
macher], pl. 14, fig. 1. Also mentioned were, “‘Solen
ensis Lin. Solen siliqua Chemm. 6. pag. 44. Tab. 4, fig.
29.”—Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 5,
pp. 950, 954, 1900. “Type S. magnus Linneé.” — Coss-
mann and Peyrot, Act. Soc. Linn. Bordeaux, Tome 63

309

(Conch. Néogéne de L’ Aquitaine, Tome 1), Livr. 1, p.
150, 1909. “G.-T.: Solen ensis Linné.”” — Gardner,
U. S. G. S., Prof. Paper 142-E, p. 217, 1928. “Type
Ensis magnus Schumacher.”

Type species (by tautonomy, and by subsequent
designation by Herrmannsen, Indic. Gen. Malcozoo., Vol.
1, p. 423, 1846).—‘‘Typus: Solen ensis Linn.” [Syst. Nat.,
ed. 10, p. 672, 1758. “‘Habitat in M. Mediterraneo, Ang-
lico.” Ref. to “List, angl. app. t. 2. f. 9” and “‘Argenv.
conch. t. 27. f. L? Also illustrated by Sowerby in Reeve’s
Conch. Icon., Vol. 19, Solen, species 3, pl. 1, fig. 3, 1874.
“Hab. Great Britain.” — Van Urk, Basteria, Vol. 28, No.
1 and 2, p. 37, pl. 1, fig. 4, 1964. ““North Sea-Mediterra-
nean.”’ For discussion of this species see Dodge, H., Bull.
Amer. Mus. Nat. Hist., Vol. 100, Art. 1, pp. 34-35, 1952.]

Range.—Eocene; Miocene to Recent. Recent, world
wide in warm temperate and tropical waters, in soft in-
shore sands and muds, but also offshore (off Florida) to
a depth of 91 meters (50 fathoms), and perhaps deeper.

Description. — Valves thin, seabbard-shaped, slight-
ly gaping, usually somewhat arcuate; umbones flattened,
subterminal; ligament external, opisthodetic; hinge of
right valve armed with one vertical and one horizontal
lamelliform cardinal, that of the left valve with two prox-
imate vertical cardinals and one horizontal; anterior
adductor impression conspicuous, elongated in the general
direction of the major axis; pallial line rather distant from
the ventral margin, sinuate posteriorly (Gardner, 1928.)

Remarks. — Some authors place the genus Ensis in
the family Cultellidae.

The presence of Ensis in beds of Tertiary age in wes-
tern North America is reported here for the first time.
However, it has been reported from beds of Pleistocene
age in this region by several authors. One species now lives
in warm temperate waters in this region and two in south-
ern tropical waters. This genus is known to occur in
Florida and in Europe in strata of Miocene age.

Holmes (1137) gave an excellent discussion of the
three Recent British species including their ecology and
more recently Van Urk (1138) discussed the European
species of Ensis. Some species of Ensis are described as
able to move about very quickly in their burrows.

Ensis myrae Berry
Plate 57, Figures 7, 19

Ensis californicus Dall, I. S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 189, pl. 49, fig. 6,
1924. “San Pedro.” [The plate and figure are erron-
eously cited under the caption to Solen sicarius
Gould, p. 188.]

Not Ensis californicus Dall, 1899.

Ensis myrae S. S. Berry, Trans. San Diego Soc. Nat. Hist.,
Vol. 11, No. 15, pp. 398, 399, figs. 3, 4, August 14,
1953.

Type specimen. — No. 7582, Stanford University.
Type locality. — ‘San Pedro Bay, California; mainly
cast up by storms in the vicinity of Terminal Island.”
Range. — Middle Pliocene to Recent. Recent from

Monterey, California, to Islas Los Coronados, Lower

California, in 14 to 46 meters (8 to 25 fathoms) to 91

meters (50 fathoms) according to Valentine and Mead

310

(Univ. Calif. Publ. Geol. Sci., Vol. 40, No. 1, p. 26, 1961).

Occurrence in San Diego Fm. — C.A.S. 28889,
98892. L.A.M. 107, 305, 305A, 318, 319.

Original description. — Shell of moderate size and
slenderness, rather strongly falciform; valves narrowing
slightly and rather sharply and squarely truncate in front,
more rounded and narrowing a little more steadily and de-
cidedly posteriorly. Hinge-plate strongly anterior in pos-
ition, small and comparatively short; right major cardinal
compressed, squarish in profile, strongly projecting; right
posterior cardinal slender, short (appreciably less than
one-tenth the length of the shell), laminar, terminating in
a short free flange; left major cardinals strongly unciform
and considerably heavier than that in the right valve; inner
left posterior cardinal generally similar to its mate of the
right valve, the weaker outer cardinal closely adnate to
the shell margin. Exterior of shell mostly with a somewhat
silky sheen due to the numerous fine growth-striae under-
lying the thin shining Sayal Brown to Mikado Brown per-
iostracum; in adult shells the periostracum is usually
rubbed away in a blade-shaped swath extending from the
beaks to the posterior margin, this area being white except
for some ruddy or purplish coloring, especially along the
edges of the area and in the incremental rest-marks, where
the Deep Rose Pink or Vinaceous tinting of the interior
may shine through. Maximum longitude, 81.3 mm.,
altitude, 11.9 mm., percentage of altitude to length,
14.6 mm., diameter 5.8 mm. (Berry.)

Remarks. — One fairly well preserved right valve of
an Ensis and many fragments from Locs. 305 and 305A
(LAM), and fragments from Loc. 319 (LAM), all from
near the Mexican boundary, are present in the collections
of the Los Angeles County Museum. These agree in all
observable details with Recent shells of Ensis myrae
Berry. The large right valve is 63.9 mm long and 10 mm
high. A cast retaining portions of the shell material, from
Loc. 28892 (CAS), also from near the Mexican bound-
ary, appears to be referable to E. myrae.

This species was described as differing from E.
californicus Dall (1139) in the greater size, less slender
outline, greater arcuation, squarish rather than rounded
anterior end, the pallial line nearer the margin, and in
minor details of the hinge.

We have not studied a series of specimens of E.
californicus but the single valve from Manzanillo, Mexico,
reported by Hertlein and Strong (1140), 60.5 mm long,
and 7.3 mm high, has an outline more slender than that of
E. myrae but the anterior end much less rounded than
that shown in Berry’s (1141) drawing of a specimen of E.
californicus from San Felipe, in the Gulf of California.

The ratio of height to length of the type of E. cal-
ifornicus is 12.1, of the left valve reported from Manzan-
illo, Mexico, 11.7, that of the type of E. myrae 14.6 and
that of the right valve from the San Diego Formation,
15.6.

The only other species of Ensis described from
eastern Pacific waters is Ensis tropicalis Hertlein and
Strong (1142), the outline of which is only slightly ar-
cuate and in this character it resembles some species of
Solen.

Ensis myrae, at times, has been mistaken for Solen
rosaceus, The nearly straight anterior end of the pallial
line and the gently obliquely sloping anterior retractor
muscle impression are features which aid in separting even

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

fragments of the anterior end (when the interior is ex-
posed) from Carpenter’s species. The corresponding mus-
cle impression on S. rosaceus is wider and parallel to the
dorsal margin of the valve.

GENUS SILIQUA MEGERLE VON MUHLFELD

Siliqua Megerle von Miihlfeld, Gesell. f. Naturfor. Freunde
zu Berlin, p. 44, 1811. Sole species: Siliqua radiata
Linnaeus. Ref. to “Linn. Syst. Nat. Gen. 304. Sp. 6”
and ‘“‘Chemn. Conch. 6, t. 5. f. 38. -40.”” — Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 386,
1931. Type, Solen radiatus Linnaeus.

Leguminaria Schumacher, Essai Nouv. Syst. Hab. Vers
Test., p. 126, 1817. Type (by monotypy): Legum-
inaria costata Schumacher, p. 126, pl. 7, fig. 1
[ = Solen radiatus Linnaeus].

Machaera Gould, Invert. Massachusetts, p. 32 1841. So-
len radiatus Linnaeus and other species cited.

Not Machaera Cuvier, 1832.

Type species (by monotypy). — “Siliqua radiata”
Linnaeus [ = Solen radiatus Linnaeus, Syst. Nat., ed. 10,
p. 673, 1758. “Habitat in O. Asiatico.” Ref. to ‘““Rumph.
mus. t. 45. f. E.”; “Gault. test. t. 91, f. B.”; “Argen.
conch. T. 25. f. P.” Illustrated by Sowerby in Reeve’s
Conch. Icon., Vol. 19, Cultellus, sp. 13, pl. 4, fig. 13,
1874. “Hab. Sumatra.” For a discussion of this species
see Dodge, Bull. Amer. Mus. Nat. Hist., Vol. 100, art.
2, p. 36, 1952.]

Range. — Late Cretaceous?; Eocene to Recent. Re-
cent from the intertidal zone to about 55 meters (30 fat-
homs).

Description. — Shell oblong, length about three
times as great as the height, somewhat compressed,
smooth, ends rounded, gaping, beaks about one third to
one fourth the distance from the anterior end; interior of
valves with a flattened rib posterior to anterior muscle im-
pression, extending from beneath the beaks to the ven-
tral margin; hinge with 2 small, close cardinals in the left
valve and one in the right; pallial sinus large, short,
rounded.

Remarks. — Siliqua alisoensis Packard (1143) was
described from strata of late Cretaceous age in the Santa
Ana Mountains in southern California. An internal rib was
present on the anterior portion of the shell. The hinge was
not described and there may be doubt as to whether this
species is referable to Siliqua or to some similar genus
Leptsolen Conrad, a Cretaceous genus, also has an inter-
nal rib. Senis Stephenson, which resemble Siliqua in exter-
nal features, is said to lack hinge teeth. The genus Siliqua
has been recorded from strata of Eocene age in Texas
(1144) and in Japan (1145). Gardner (Univ. Texas Bull.
3301, p. 188, 1935) reported “Siliqua? sp.’ from the
upper Midway Group now believed to be of Paleo-
cene age.

No species of Siliqua have been reported from the
early Tertiary strata of California but the genus is def-
initely known to occur from late Miocene (Briones) to
Recent. It has been reported from western Oregon in beds
of middle Miocene age and in northern California in strata
of late Miocene age and in beds of Pliocene age.

Siliqua is essentially an inhabitant of cool waters.

|

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Five species are known to occur in west American waters
between the Arctic Ocean and Todos Santos Bay, Lower
California. According to Paul Bonnot (1146), S. patula
lives in sand close to the surface, the hinge toward the sea.

This genus was included in the family Cultellidae by
Keen in 1969.

Siliqua lucida Conrad
Plate 49, Figure 2

S[olecurtus]. lucidus Conrad, Jour. Acad. Nat. Sci. Phil-
adelphia, Vol. 7, Pt. 2, p. 231, pl. 17, fig. 8, 1837.
Siliqua lucida Conrad, I.S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 189, pl. 52, fig. 2,
1924. “‘Range. Monterey, California, to Todos Santos
Bay, Lower California. In the Pleistocene at San Pedro
and San Diego, California.”—Johnson and Snook, Sea-
shore Animals of the Pacific Coast (Macmillan and Co.:
New York), pp. 458, 460, fig. 458, edit. 1935. Mont-
erey, California, to Lower California. — Morris, A
Field Guide to Shells of the Pacific and Hawaii
(Houghton Mifflin Co.: Boston), p. 55, pl. 14, fig. 6,
1952. Bolinas Bay, California, to Mexico.—Hertlein,
Bull. South. Calif. Acad. Sci., Vol. 60, Pt. 1, pp. 14-15
(in text), pl. 5, figs. 4, 5, 6, 1961. From breakwater at
North Island, Los Angeles County, California, Recent.
Type specimen. — Syntypes, four valves, Nos. 61.5.
20.133 (3 valves) and 57.8.14.2 (single valve), British
Museum (Natural History) (A. M. Keen, Veliger, Vol. 8,
No. 3, p. 170, 1966).

Type locality. — “‘Inhabits the sand-beach, near Sta.
Barbara; uncommon.”

Range. — Late Miocene (Briones) to Recent. Re-
cent from Bolinas Bay, California, to San Quintin Bay,
Lower California, Mexico, on sandy beaches and to the
depth of 46 meters (25 fathoms).

Occurrence in San Diego Fm. — L.A.M. 107, 305,
305A, 319. S.D. 83. U.C.L.A. 1386.

Original description. — Shell oblong, oval, com-
pressed, thin, fragile, translucent; posterior extremity
nearly direct, truncated; colour blueish, with purple con-
centric zones, and two oblique pale rays on the posterior
side; interior rib nearly direct. (Conrad.)

Remarks. — One specimen retaining much of the
shell and four others less perfectly preserved were col-
lected by Frank Stephens on Reynard Way in San Diego.
The largest specimen (incomplete) is 36.5 mm long. The
shape and observable characters of this and the accom-
panying specimens are comparable to Recent specimens of
Siliqua lucida of the same size. Recent specimens 55 mm
long have been reported from Morro Bay, California. Two
imperfect casts from Kensington Park, San Diego, may be
referable to this species. Two small single valves about 18
mm long and a left valve 28.5 mm long, from Loc. 107
(LAM), appear to be referable to this species. The ant-
erior portion of a left valve, about 18 mm long from Loc.
305 (LAM), agrees in shell characters with the corres-
ponding portion of a Recent valve of S. lucida. Many
fragments, probably referable to this species, are present
in the collections of the Los Angeles County Museum
from Locs. 107, 305, 305A, and 319.

The shell of Siliqua lucida is separable from that of

311

young specimens of S. patula in that it is smaller and
much more elongate, the ventral margin is more arcuate,
the anterior end is shorter and the posterior end is some-
what more truncated. The shell of S. lucida is very thin
and the exterior of live specimens is gray tinged with vio-
let, whereas that of S. patula is covered with a shiny, light
brown periostracum. The interior rib of the present spec-
ies is nearly vertical rather than inclined anteriorly and in
this character it more resembles the northern S. media
Sowerby.

Siliqua sloati Hertlein (1147), a Recent species des-
cribed from off California, differs from S. lucida in the
more roundly pointed posterior end and in the less ex-
panded posterior dorsal area which is not bordered by a
distinct groove.

An intensive study of Siliqua patula Dixon, a large
form of commercial value, was made by Weymouth, et al.
(1148) According to those authors, S. patula attains a
maximum age of 19 years. Large specimens are 170 mm
long.

SUPERFAMILY MACTRACEA BOWDICH (1149)
FAMILY MACTRIDAE BOWDICH (1150)

Shell roundly trigonal or oblong; closed or slightly
gaping; lunule and escutcheon not well defined; surface
usually marked only with lines of growth, rarely with
strong concentric sculpture; beaks inclined anteriorly;
ligament opisthodontic, short; resilium triangular or ovoid
and situated in a deep pit, usually on a downward project-
ing hinge-plate (chondrophore) which is posterior to the
cardinals; hinge of left valve usually with one bifid V-
shaped cardinal, sometimes with accessory shelly pro-
cesses, and usually with an anterior and a posterior lateral
tooth; all these fit into sockets or paired laminae in the
right valve; pallial sinus well developed; adductor impres-
sions subequal, peripheral. Cretaceous to Recent.

Remarks. — This family includes a number of gen-

Key (1158) to Genera and
Subgenera of Mactridae

A. Shell broadly gaping posteriorly;
outline ovately
rectangular . . Tresus
B. Shell narrowly gaping or
closed; outline usually
ovately subtrigonal.
a. Chondrophore separated from
resilium by a shelly
lamina Nice a ae . Mactra (1159)
aa. Chondrophore not separated from
resilium by a shelly lamina.

b. Lateral teeth moderately long;
beaks nearly centrally
situated ia) (oar) ce

bb. Lateral teeth short; beaks
more anteriorly
situated .

. Spisula s. s.

. (subgenus) Mactromeris

312

era and subgenera. About a dozen species have been re-
corded from Pliocene strata of California, Oregon, and
Washington. Eleven species occur in marine waters be-
tween the Bering Sea and San Diego, California, and 24
species have been recorded living in tropical and subtropi-
cal waters of the western Americas.

The family Mactridae has been the subject of special
studies by Gray (1151), Dall (1152), and Lamy (1153).
A paper by Packard (1154) deals with Mesozoic and
Cenozoic Mactridae of western North America, chiefly
north of Mexico and papers by Hertlein and Strong
(1155), by Keen (1156), and by Olsson (1157) contain
discussions of a number of tropical west American
species.

GENUS SPISULA GRAY

Spisula Gray, Mag. Nat. Hist., New Ser., Vol. 1, p. 372,
July, 1837. Many species cited including ‘‘Spisula
solida; Mactra solida Montague” (p. 374).—Dall, Trans.
Wagner Free. Inst. Sci., Vol. 3, Pt. 4, p. 895, 1898. —
Lamy, Jour. de Conchyl., Vol. 63, No. 4, p. 291, 1918.
Type: Mactra solida Linnaeus. -- Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 2, p. 393, 1931. Type:
Mactra solida Linnaeus as indicated by Gray, 1847. —
Olsson, Mollusks of the Tropical Eastern Pacific Pal-
eo. Res. Inst.: Ithaca, New York), p. 326, 1961. Type
as indicated by Gray.

Type species (designated by Gray, Proc. Zool. Soc.
London for 1847, p. 185). — “‘M. solida”. [= Cardium
solidum Linnaeus, Syst. Nat., Ed. 10, p. 681, 1758. “‘Hab-
itat in O. Anglico.” Ref. to “Bonan. recr. 3. t. 51”;
“Ronds test. lee. (73 List Angi. di74. t. 4° £24". —
Lamy, Jour. de Conchyl., Vol. 63, No. 4, p. 295, figs. of
hinge (p. 292), 1918. (With synon.). —Dodge, Bull. Amer.
Mus. Nat. Hist., Vol. 100, Art. 1, p. 75, 1952.]

Key to Species of Spisula

A. Valves compressed; adult shell usually
less than 70 mm long.

a. Shell subtrigonal; beaks
nearly central . , : planulata
aa. Shell elongately trigonal; beaks
decidedly anterior falcata
B. Valves inflated; adult shell usually
more than 70 mm long.
a. Beaks posterior to the middle
of valves , hemphilli
aa. Beaks anterior to the "middle
of valves.
b. Posterior flexure distinct;
ovately elongate in outline
or ovately subtrigonal. . catilliformis

bb. Posterior flexure indistinct;
very elongate in outline,
the beaks more anteriorly

situated . . mercedensis

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Range. — Middle Eocene to Recent. Recent from
the littorial zone to 110 meters (60 fathoms): occasionally
deeper.

Original description. — Shell ovate, trigonal, sub-
angular at each end. Hinge and lateral teeth as in Mactra;
but hinge tooth of left valve very small. Siphonal inflec-
tion ovate, distinct. Ligament just within the cardinal
edge, over the top of the cartilage, and not separated from
it by any shelly plate; and partly hid from view by the
hinge margin. (Gray.)

Remarks. — The generic and subgeneric assignment
of many species to Mactra or to Spisula, especially fossil
forms, is doubtful due to the difficulty of detecting
whether or not the resilium is separated from the ligament
by a shelly lamina. Five species which occur in the San
Diego Formation are referable to Spisula (1160).

Eight species referred to Spisula have been reported
as occurring in strata of Pliocene age in western United
States. Six species are known to occur in marine waters
between the Bering Sea and San Diego, California.

{Mactra albaria Conrad]

Mactra albaria Conrad, Amer. Jour. Sci., Ser. 2, Vol. 5,
p. 432, fig. 4, 1848. Reprint by Dall, U.S. G. S., Prof.
Paper 59, p. 150, fig. 4, 1909. — Dall, cited by Ellis in
Ellis and Lee, U. S. G. S., Water Supply Paper 446, p.
63, 1919.

Type specimen.—‘Holotype: Missing and presumed
lost.” (Moore, Ellen, U. S. G. S., Prof. Paper 419, p. 83,
1963.)

Type locality.—‘‘Near Astoria. .
le Miocene. |

Range. — Miocene.

Occurrence in San Diego Fm. — “About 3 1/4
miles east of Chula Vista and 1 1/4 miles southeast of
Bonita the north wall of a small canyon, locally known
as Fossil Canyon. . .about 300 feet above sea level.”
(Dall, cited by Ellis in Ellis and Lee.)

Remarks. — The only record of the occurrence of
this species in the San Diego Formation is that of Dall
cited by Ellis. Mactra albaria was originally described
from Astoria, Oregon, where it occurs in beds of middle
Miocene age. It has been recorded as occurring in beds of
Pliocene age in northern and central California, as well as
in Oregon and Washington, but it has not been recorded
from Pliocene strata in the Los Angeles basin nor south of
there.

Spisula albaria var. coosensis. (1161) from the Plio-
cene of Coos Bay, Oregon, was described by Howe. This
form attains a large size and lacks the pronounced angula-
tion such as occurs on S. a/lbaria from the beak to the pos-
terior (1162) ventral margin. Howe also mentioned diff-
erences in the hinges of the two forms. Those from As-
toria “show the left cardinal to extend uniformly from
the beaks to the edge of the chondrophore, while in var.
coosensis the left cardinal extends only two-thirds of this
distance.’”’ There also is said to be a difference in the char-
acters of the hinge of the right valve of the two forms.
Weaver (1163) cited the range of S. albaria as “Upper
Miocene to Recent’’, but so far as known it does not oc-
cur in the post-Miocene fauna. It appears likely that Pli-

-Teriary.”’ [Midd-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

ocene records of S. albaria may be referable to S. a.
coosensis.

In view of the fact that neither Spisula albaria nor
S. a. coosensis has been observed in any of the collec-
tions from San Diego and as the sole record is that of Dall
in a general faunal list by Ellis, we are inclined to consider
this to be an invalid record for the San Diego Formation.

SUBGENUS MACTROMERIS CONRAD

Mactromeris Conrad, Amer. Jour. Conch., Vol. 3, Cat.
Mactridae, ap. p. 45, January 2, 1868. Seven species
(including several synonms) cited of which S. ovalis,
Gould’’, is first. — Stewart, Acad. Nat. Sci. Philadel-
phia, Spec. Publ. No. 3, p. 207, 1930. ‘Type species
Mactra ovalis Gould, designated by Stoliczka.” —
Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol.
1, p. 394, 1931. “Type (by subsequent designation,
Dall, 1898), M. polynyma Stimpson.’’ — Olsson, Moll-
usks of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 323, 1961. ‘Type species by
subsequent designation, Dall, 1898, Spisula ovalis
Gould ( = Mactra polynyma Stimpson).”

Symmorphomactra Dall, Nautilus, Vol. 8, No. 4, p. 41
August, 1894. Sole species. “‘Spisula (Symmorpho-
mactra) falcata Gld., 1850. Comox, Br. Col. to San
Pedro, Cala.”

Type species (designated by Stoliczka, Mem. Geol.
Surv. India, Palaeont. Indica, Ser. 6, Vol. 3, Pelecypoda,
p. XVI, 1871. — “‘St. ovalis, Gray,’ (on p. 53 cited as
“Standella ovalis, Gould’’) [ = Mactra ovalis Gould, Amer.
Jour. Sci., New Ser., Vol. 38, p. 196, 1840. [ No locality
cited.] — Gould, Invert. Massachusetts, p. 53, pl. 3, fig.
32, 1841; ed. by Binney, 1870, p. 75, fig. 32. (Not Mactra
ovalis G. B. Sowerby, 1818. Crag, Pliocene of England).
Gould’s species was renamed Mactra polynyma by Stimp-
son, Smithsonian Misc. Coll., Vol. 2, Art. 6, No. 3, p. 3,
1860. For synonymy of this species see Lamy, Jour. de
Conchyl., Vol. 63, No. 4, p. 319, hinge illustrated p. 198,
UST] |

Range. — Miocene to Recent. Recent in boreal and
warm temperate waters. One or two species in tropical
west American waters have been referred to Mactromeris.

Description. — Shell of moderate or large size;
beaks more anteriorly placed than in Spisula s. s.; hinge of
left valve with small accessory lamina posterior to the car-
dinal tooth, right valve with anterior cardinal separate
from lower anterior lateral; lateral teeth smooth. (Ad-
apted from Lamy, and Grant and Gale.)

Remarks. — The hinges of many of the groups of
Mactridae are quite similar. The group segregated under
Mactromeris possess a hinge similar in general features to
Spisula s. s. as mentioned by Stewart. They differ in that
the laterals are proportionately shorter, the beaks are
more anteriorly situated and the pallial sinus is longer.

A subgenus of Spisula, Symmorphomactra, was
proposed by Dall in 1894 with the sole species Spisula
(Symmorphomactra) falcata Gould. This subgenus was
described as “teeth of Mactrotoma, s. s., hinge of
Spisula.”’ The following year Dall (1164) did not cite this
category in his synopsis of the Mactridae. In 1921 he
(1165) placed Spisula falcata in the subgenus Hemimactra,

313

section Mactromeris, and referred only one species, S.
planulata Conrad, to Symmorphomactra.

Some authors consider Symmorphomactra to lack
systematic value. The current classification of genera and
subgenera of west American Mactridae is not entirely
satisfactory. For the present we have S. falcata and S.
planulata in Mactromeris.

The hinge of Hemimactra Swainson (1166) differs
from that of Mactromeris in that the cardinals are almost
obsolete and the laterals are transversely striated.

Recent species of Mactromeris are almost restricted
to the region encompassed by boreal to warm temperate
waters along both coasts of North America and Japan.
There are about six species living in west American waters
and about the same number of species have been des-
cribed as fossils in that region.

Spisula (Mactromeris) catilliformis Conrad
Plate 54, Figures 5, 7

Spisula catilliformis Conrad, Amer. Jour. Conch., Vol.
3, No. 2, p. 193, September 5, 1868. — Conrad, Amer.
Jour. Conch., Vol. 5, Pt. 2, p. 108, pl. 13, fig. 1, Oct-
ober 7, 1869.

Mactra (Spisula) catilliformis Conrad, Arnold, Mem. Calif.
Acad. Sci., Vol. 3, p. 62 (“Pacific Beach,” “‘Pliocene”’),
p. 176 “‘Pliocene. — San Diego (Arnold)’’, pl. 19, fig. 5
(“Upper San Pedro series, San Pedro’’), 1903.—Ar-
nold, U.S.G.S., Prof. Paper 47, p. 28, 1906. ‘‘San Diego
formation as developed in the type section at Pacific
Beach north of San Diego.’’ — Reagan, Trans. Kansas
Acad. Sci., Vol. 22, p. 202, 1909. ‘‘Purisima-San
Diego.” — Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, p. 398, pl. 23, figs. 4 and 10 (from
Etchegoin), 1931. “‘Pacific Beach, San Diego (Arnold,
1903.)”

Mactra catilliformis Conrad, J. P. Smith, Proce. Calif.
Acad. Sci., Ser. 4, Vol. 3, p. 172, 1912. “San Diego-
Purisima.”’ Pliocene.

Spisula catilliformis Conrad, Packard, Univ. Calif. Publ.
Bull. Dept. Geol., Vol. 9, No. 15, p. 285, pls. 17, 18,
19, May 1, 1916. Middle Miocene to Recent. — Pack-
ard, Univ. Calif. Publ. Zool., Vol. 14, No. 2, p. 282,
pl. 27, figs. 1, 2; pl. 24, fig. 2, 1918. “Range. — Straits
of Juan de Fuca, Washington, to San Diego, Califor-
nia.” I.S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 194, pl. 24 (reproduction of pl.
17 of Packard, 1916), 1924. “Pliocene at San Diego.”
Also other occurrences. Recent from ‘‘Neah Bay,
Washington, to San Diego, California.”—Fitch, State
Calif. Dept. Fish Game, Mar. Fish. Branch, Fish Bull.
No. 90, p. 87, fig. 53, 1953. ‘“‘Range: San Francisco
Bay to San Diego Bay.” —Abbott, American Seashells
(D. Van Nostrand Co.: New York), p. 448, fig. 90c,
1954. Washington to Ensenada, Lower California

Type specimen. — Location unknown to the pre-
sent authors.
Type locality. — “Inhabits Panama’ [As stated by

Dall (Nautilus, Vol. 7, No. 12, p. 137, pl. 5, fig. 3, 1894),

this species was “‘erroneously stated to have come from

Panama.” In this paper Dall cited the distribution as

“Neeah Bay to San Diego, Cala.’’]

314

Range.—‘‘cf.”’ Early and middle Miocene (Vaqueros
and Temblor formations); late Miocene to Recent. Recent,
from Neah Bay, Washington, to San Quintin Bay, Lower
California, in 18 to 73 meters (10 to 40 fathoms), ocea-
sionally in shallower water. “Lives in fine sand or firm
sandy mud in bays, sloughs and estuaries as well as more
quiet protected areas along the outer coast” (Fitch).

Occurrence in San Diego Fm. — C.A.S. 1140, 1182,

1400. L.A.M. 104, 107, 305, 305A, 309, P.87, A-1323.
Original description. — Suboval, inequilateral; an-

terior side slightly flattened or contracted; posterior side
with an oblique shallow groove or fold; lines of growth
coarse and prominent; lunule very long, elliptical; ventral
margin tumid posteriorly; cardinal pit oblique, large;
pallial sinus extending beyond the middle of the valve.
Length 4 5/8 inches; height 3 7/8 inches. (Conrad.)

Remarks. — A number of specimens of Spisula
catilliformis, in various states of preservation, are present
in the collections from the San Diego Formation. There is
variation in the outline of a series of specimens, some are
decidedly more triangular than others. A large cast, re-
taining some shell material, from Loc. 107 (LAM), at the
end of Arroyo Drive, San Diego, is 129.5 mm long and
99 mm high. Another smaller cast from the same locality
is 92 mm long, 71 mm high, convexity (both valves
together), 47 mm. A specimen retaining most of the shell
material from Loc. 305 (LAM), near the Mexican bound-
ary, is 124 mm long, 102 mm high, convexity (both
valves together) 62 mm. The beaks are approximately
57 mm from the anterior end of the shell. A Recent
specimen, in the collections of the California Academy of
Sciences, from Halfmoon Bay, California, is 134 mm long,
104 mm high, convexity (both valves together) approx-
imately 61 mm, beaks situated about 49 mm from the
anterior end of the shell, and the pallial sinus extends
forward about 49 mm from the posterior end of the
shell. A smaller specimen from Loc. 37138 (CAS), Mont-
erey, California, is 109 mm long, 81 mm high, convexity
(both valves together) 50 mm, the beaks are about 45
mm from the anterior end of the shell. The hinges as well
as the other shell characters of the fossils are all com-
parable to Recent specimens of the same size.

The fossils from beds of Pliocene age in the Santa
Maria district, California, cited by Woodring (1167) under
the name “‘Spisula ef. S. catilliformis Conrad” were said
to refer to the short, rounded form described from that
area by Arnold under the name of Spisula catilliformis
var. alcatrazensis (1168). He mentioned, however, that no
Recent specimens of S. catilliformis are as short as the
fossils from Santa Maria.

Spisula (Mactromeris) cf. S. (M.) falcata Gould
Plate 54, Figure 8; Plate 57, Figure 12

The following references, type locality, range and
description refer to typical S. falcata.

Mactra falcata Gould, Proc. Boston Soc. Nat. Hist., Vol.
3, p. 216, May, 1850. — Gould, U. S. Explor. Exped.
(Wilkes), Vol. 12, p. 393, 1852, Moll., Atlas, p. 13, pl.
34, figs. 506, 506a, 506b, 1856. — Gould, Otia Conch.,
p. 76, 1862. | Original description reprinted. |

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Spisula planulata Conrad, Packard, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 9, No. 15, p. 293, pl. 16, figs. 3a, 3b,
3c, 1916.

Not Mactra planulata Conrad, 1837.

Spisula falcata Gould, I. S. Oldroyd, Publ. Puget Sound
Biol. Sta., Vol. 4, p. 60, pl. 17, figs. 1-3, 1924. [ Repro-
ductions of Gould’s original illustrations, figs. 506,
506b.] ‘“‘Puget Sound to Cortez Bank and the Coron-
ado Islands, Mex.” — I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 195, pl. 20, figs.
1-3, 1924. [Reproduction of Gould’s original illustra-
tions, 506, 506b. |

Type specimen. — No. 5893, United States Nat-
ional Museum.

Type locality. — “Hab. Puget Sound, Oregon.”
[ Washington. |

Range. — Middle Pliocene (1169) to Recent. Recent
from Queen Charlotte Islands, British Columbia, to San
Diego, California, and Cortez Bank, and Coronado Is-
lands, Mexico, in 4 to 50 meters (2 to 24 fathoms).

Occurrence in San Diego Fm. — L.A.M. 305A.

Original description of Mactra falcata. — Testa
magna, transversa, ovatotrigona, inequilateralis, convex-
iuscula, modice hians, albida, epidermide fulvo, nitido,
concentrice rugoso induta; umbonibus acutis, approxima-
tis; latere antico acuminato; latere siphonali laté rotunda-
to, sub-truncato; margine dorsali recto; area dorsali plan-
ulata, lanceolata; margine ventrali leniter arcuato; area
cardinalis ampla; fossa ligamentali magna, dente V-formi
parvo, classo, dentibus lateralibus compressis, quorum an-
tico valvae dextrae bilobato; interior lactea; sinu siphon-
ali angusto, elongato, spatulato. Long. 3 3/4; alt. 2 1/2;
lat. 1 1/8 poll. (Gould.)

Remarks. — The specimen here provisionally identi-
fied as Spisula falcata is a small right valve 18 mm long
and 11.6 mm high. The preservation is imperfect, but the
very inequilateral outline and the remnant of the hinge
agree well with juvenile specimens of S. falcata.

Reagan (Trans. Kansas Acad. Sci., Vol. 22, p. 204,
1909) reported “‘Mactra (Spisula) falcata Gould” from the
Quillayute Formation in western Washington of Pliocene
age and also from the ‘“‘Purisima-San Diego” formation.
This record from San Diego, however, is equivocal in that
two formations from California are mentioned.

Spisula falcata brioniana Trask (1170) from the
Briones Formation of late Miocene age, was described as
differing from the typical species in the greater height in
proportion to the length, more prominent umbonal ridge,
shorter hinge plate and shorter distance from the center
of the hinge plate to the distal ends of the lateral lam-
ellae.

Spisula falcata bears a resemblance to S. dolabri-
formis Conrad (1171), which also is an elongated form,
but may be separated from it by the character of the
hinge. The right anterior accessory lamina extends toward
and is separated from the lower lateral by only a slight
gap whereas in S. dolabriformis the corresponding lamel-
lae are offset and separated by a comparatively wide
space. The same difference in the hinge also exists be-
tween S. falcata and S. planulata Conrad. The latter is
much more equilateral and the shell is thicker.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Spisula (Mactromeris) hemphillii Dall
Plate 54, Figures 1-4, 9, Plate 57, Figure 16

Mactra hemphillii Dall, Nautilus, Vol. 7, No. 12, p. 137,
pl. 5, fig. 2, April, 1894. “Distribution: San Diego,
Hemphill and Cooper.” Recent. — Reagan, Trans.
Kansas Acad. Sci., Vol. 22, p. 204, 1909 (as Mactra
hemphilli). Quillayte Formation, western Washington,
Pliocene. Also “‘Purisima-San Diego.”

Spisula hemphillii Dall, Packard, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 9, No. 15, p. 287, pls. 21 and 22,
May 1, 1916. Earlier records cited, Recent and
Pleistocene. J. Q. Burch, Min. Conch. Club South.
Calif., No. 44, p. 19, figs. (on p. 11 by T. A. Burch),
February, 1945. “‘Redondo Beach, Calif. (Burch) to
Corinto, Nicauragua [Nicaragua] (Eyerdam)” (1172).

Spisula hemphilli Dall, 1. S. Oldroyd, Stanford Univ. Publ.
Univ. Serv. Geol. Sci., Vol. 1, p. 194, pls. 46, 50 (re-
production of pls. 21, 22, by Packard, 1916), 1924.
“Range San Pedro to San Diego, California, In the

Pleistocene at San Pedro.”’ — Hertlein, Stanford Univ.
Bull., Ser. 5, No. 78, p. 83, 1929. ‘Pliocene of San
Diego.” Also ‘“‘Purisima formation.” — Fitch, State

Calif., Dept. Fish Game, Mar. Fish. Branch, Fish Bull.,
No. 90, p. 88, fig. 54, 1953. ““Range: Santa Barbara,
California, to Ensenada, Baja California.’”” — Abbott,
American Seashells (D. Van Nostrand Co., Inc.: New
York), p. 448, fig. 90b (p. 447), 1954. [ Reproduction
of Dall’s (1894) illustration. }

Type specimen. — No. 15815, United States Nat-
ional Museum.

Type locality. — “San Diego,” California.

Range. —? Late Miocene (Grant and Gale); Middle
Pliocene to Recent. Recent, Monterey (1173) (rarely)
Santa Barbara, California, to Todos Santos Bay, Lower
California, Mexico, from intertidal zone (rarely) to 46
meters (25 fathoms); ‘‘in fine or firm, sandy mud in
bays, sloughs and estuaries as well as more quiet protected
areas along the outer coast”’ (Fitch).

Occurrence in San Diego Fm. —C.A.S. 1402, 28892.
L.A.M. 107, 305, 305A, P.87, A-1323. S.D. 29, 331,
2939, 2946, 3592. U.C.L.A. 294, 312.

Original description.—Shell large, thin, inflated, sub-
equilateral, creamy white with a yellow thin epidermis,
which over the body of the shell in young shells is beauti-
fully evenly concentrically striated and on the posterior
dorsal area is irregularly wrinkled, with an elevated raphe
of epidermis at the margin of the area; beaks rather prom-
inent, the anterior end of the valves longer than the pos-
terior; posterior dorsal slope excavated; lunule obscure,
escutcheon marked by prominent elevated radial lines of
epidermis; the dorsal margin pouting in front of the lig-
ament, the posterior slope convex, the posterior flexure
faint, but marked by a recession of the ventral border of
the valves, which gape but very little and not at all in
front; anterior end rounded, but smaller than the poster-
ior; ventral border arcuate; hinge and pallial sinus much as
in the last species [Mactra catiliformis|] except that the
sinus is somewhat smaller and less depressed. Lon. 120,
alt. 93, diam. 50 mm. (Dall.)

Remarks. — Several well preserved specimens and
many fragments of Spisula hemphillii from the San Diego
Formation agree in all observable details with part of the

type lot of that species. The largest specimen from Loc.
2946 (SD), from Reynard Way, San Diego, retaining most
of the shell material, is 134.4 mm long, 102 mm high,
convexity (both valves together) 48.8 mm. A specimen
from Fossil Canyon east of Chula Vista [Loc. A1323
(LAM)], retaining patches of shell material, is 132.8
mm long, 104 mm high, convexity (both valves together),
58 mm. A smaller specimen, a right valve from Loc. 305
(LAM), near the Mexican boundary, is 114 mm long,
85 mm high, convexity 24 mm. Additional specimens
from near the Mexican boundary in various states of pre-
servation, are referable to this species.

A specimen from Loc. 28892 (CAS), from near the
Mexican boundary, is 42 mm long, 31 mm high, convex-
ity (both valves together), 17.4 mm. It agrees in all obser-
vable details with juvenile specimens in the original lot
of S. hemphillii.

Five Recent specimens in the collections of the Cal-
ifornia Academy of Sciences, collected at San Diego by
Henry Hemphill, apparently are part of the original lot
upon which the species was based. The largest specimen is
133 mm long, 102 mm high, the convexity (both valves
together) 51.3 mm. The pallial sinus extends forward 55
mm from the posterior end of the shell.

Grant and Gale (1931, p. 398) pointed out that
there appears to be but little if any difference between
the form described as Spisula cameronis, Dall (1174),
from beds of Pleistocene age at San Quintin, Lower Cal-
ifornia and S. hemphillii. It may be mentioned also that a
decided similarity exists between two other species,
Spisula mossbeachensis Glen (1175), a Pliocene species
from the lower portion of the Merced Formation, and S.
longa Dall (1176) from the Pleistocene at San Quintin.
Judging from the illustrations, the form described as
Spisula (Mactromeris) hemphilli var. orcutti Manager
(1177) is a little higher in proportion to the length, the
anterior end is a little broader and the pallial sinus is
shorter, broader, and joins the pallial line at a greater
angle than that of typical S. hemphillii.

The shell of S. hemphillii is decidedly higher in pro-
portion to length in comparison to that of S. dolabrifor-
mis Conrad (1178), the type of Simomactra Dall, which
was originally described from Panama. The same charac-
ters separate it from S. strongi T.A.Bureh (1179), which
at times has been confused with Conrad’s species. Differ-
ences in the hinges of these three species also exist.
The right valve of S. strongi has only three lateral teeth
whereas that of S. hemphillii and S. dolabriformis each
has four such teeth. The right lower anterior lateral of S.
dolabriformis is not in line with the anterior arm of the
cardinal whereas the corresponding lateral of S. hemp-
hillii is separated from but in line with the lateral.

Woodring (1180) mentioned that the fossil form
occurring in strata of a Pliocene age in the Santa Maria
district which he cited under the name of ‘‘Spisula ef. S.
hemphilli Dall” is identical with the form described by
Arnold (1181) as Spisula sisquocensis. According to
Arnold this form ‘is near S. hemphilli Dall, but is con-
stantly and decidedly narrower.”

Macrotoma revellei Durham (1182) described from
beds of Pleistocene age on Coronado Island in the Gulf of
California, resembles S. hemphillii in the general outline
but the Gulf fossil is ““more truncate posteriorly across the
gape and less rostrate anteriorly.” Furthermore, the pallial

316

sinus of S. hemphillii is considerably narrower and is dir-
ected gently upward whereas the pallial sinus on the fossil
from the Gulf of California is wider and is directed
slightly downward.

The shell of S. hemphillii is decidedly more elon-
gated anteriorly than is that of S. catilliformis and the
pallial sinus is inclined upward rather than downward as
it is in Conrad’s species.

Spisula (Mactromeris) mercedensis Packard
Plate 54, Figure 12

Spisula mercedensis Packard, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 9, No. 15, p. 286, pl. 20 [not pl.
13 as cited], figs. la, 1b, May 1, 1916. — Keen and
Bentson, Geol. Soc. Amer., Spec. Papers No. 56, p.
110, 1944. Original record cited.

Spisula (Hemimactra) mercedensis Packard, Glen, Univ.
Calif. Publ. Geol. Sci., Vol. 36, No. 2, p. 175, 1959.
Loc. B-4804, “In cliff along Highway 1, approx-
imately 4,000 feet north of Franciscan - Merced con-
tact at Mussel Rock. Fossils collected at road level
from massive, grey to brown, medium-grained sand-
stone with a few highly fossiliferous interbeds”, type
Merced, Pliocene.

Type specimen. — No. 11467, University of Calif-
ornia Department of Paleontology.

Type locality. — ‘in the marine cliffs of the Merced
group, near Mussel Rock, San Mateo County, California.”
“Pliocene: Merced group.” :

Range. — Middle Pliocene.

Occurrence in San Diego Fm. — L.A.M. 107.

Original description. — Shell large, ventricose, in-
equilateral, the beaks being considerably anterior to the
middle of the shell; anterior dorsal edge short, slightly
concave, with a faint suggestion of a lunule; posterior
dorsal edge gently convex, curving regularly to the
rounded extremity; anterior end evenly rounded; base
broadly arcuate; umbones small, sharply pointed; an in-
distinct posterior flexure extends from the umbones to
the base, much as in Spisula catilliformis Conrad. Sur-
face roughened by numerous irregular lines of growth.
Hinge plate wide, chond[r]ophore shallow, wide, over-
hung but slightly by the posterior arm of the cardinal;
left cardinal large, arms of equal length, high; anterior
lateral short, situated dorsal to the anterior arm of the
cardinal; posterior lateral high and acutely pointed.
Hinge of the right valve unknown. Pallial sinus not ob-
served. The dimensions of the type are: length 124 mm,
height 93 mm., convexity 32 mm. (Packard.)

Remarks.—One specimen of a large elongate Spisula
in the collection from Loc. 107 (LAM) retains consider-
able shell material. The left valve is 136 mm long and 93
mm high. The convexity (both valves together but some-
what overlapping) is 58 mm. The beak is approximately
62 mm from the anterior end.

The elongate outline, indistinct posterior flexure,
and anteriorly placed beaks are all characteristics of S.
mercedensis. The hinge is not visible, but according to
Packard the anterior lateral is separated from the anterior
arm of the cardinal on the left valve.

This species is evidently closely related to S. cat-

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

illiformis but the differences enumerated by Packard and
those visible on the present specimen appear to justify re-
cognition of this form as distinct from Conrad’s species.
This is the first record of S. mercedensis from strata other
than those from the Merced Formation at the type local-
ity and from southeast of Felt Lake in Santa Clara
County.

Spisula (Mactromeris) cf. S. (M.) planulata Conrad
Plate 57 Figure 12

The following references, type locality, range and
original description refer to typical S. planulata.

Mactra planulata Conrad, Jour. Acad. Nat. Sci. Philadel-
phia, Vol. 7, Pt. 2, p. 240, 1837.

Spisula falcata Gould, Packard, Univ. Calif. Publ. Bull.
Dept. Geol. Sci., Vol. 9, No. 15, pl. 26, figs. la, 1b, 1c,
1916. Recent.

Not Mactra falcata Gould, 1850.

Mactra (Spisula) planulata Conrad, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 397, 1931. Ear-
lier records cited.

Spisula planulata Conrad, Morris, Field Guide to Shells of
the Pacific Coast and Hawaii (Houghton Mifflin Co.:
Boston), p. 56, pl. 15, fig. 6, 1952. Monterey, Calif-
ornia, to Cape San Lucas, Mexico.

Type specimen. — Location unknown to present
authors. [The type specimen could not be found in the
Academy of Natural Sciences of Philadelphia, according
to Dr. Robert Robertson (written comm., March 29,
1961).]

Type locality. — “Inhabits with the former’ [that
is, Mactra californica from “Inhabits muddy marshes,
bare at low water, near Sta. Barbara; rare.”

Range. — Middle Pliocene to Recent. Recent from
Monterey Bay, California, to Cape San Lucas, Lower Cal-
ifornia, Mexico (Dall), from intertidal zone to 91 meters
(50 fathoms).

Occurrence in San Diego Fm. — L.A.M. 107.
U.C.L.A. 294.

Original description. — Shell triangular, much com-
pressed, subequilateral the posterior side rather shorter
than the anterior; anterior side subcuneiform; posterior
side with an obscure submarginal line, extremity rounded;
beaks elevated; epidermis smooth, shining. Length, one
inch and three-fourths. (Conrad.)

Remarks. — Two specimens in the present collec-
tions from near the Mexican boundary are provisionally
referred to Spisula planulata. The largest one, the dorsal
half of a right valve from Loc. 107 (LAM), is 74 mm
long and 42 mm high. The beak is a little posterior to the
middle of the valve. The lines of growth are comparable
to the corresponding ones on Recent S. planulata of the
same size. The other specimen is a small right valve, 30.8
mm long and 25 mm high, the ventral portion missing. It
bears a decided resemblance to juvenile forms of S. plan-
ulata of the same size. The characters of the interior of
these fossils is unknown and the identification is therefore
not positive.

One of the largest Recent specimens of this species
in the collection of the California Academy of Sciences,
collected at San Diego by Henry Hemphill, is 68.8 mm

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

long, 50.6 mm high, convexity (both valves together)
25.2 mm the pallial sinus extends forward 30 mm from
the posterior margin.

Spisula planulata has been confused with S. falcata
Gould in the literature. It was not illustrated at the time
of description by Conrad who stated that it was rare. The
type specimen could not be found in the collections of
the Academy of Natural Sciences at Philadelphia accord-
ing to Dr. Robert Robertson of that institution. The re-
sults of a study of the literature and of specimens from
various localities, especially from southern California, lead
us to accept the interpretation of S. planulata given by
Grant and Gale.

The shell of S. planulata, as recognized by us, is sub-
trigonal (although this character varies with juvenile
forms) and the right anterior accessory lamella is rather
steeply inclined and offset from the ventral lateral by a
comparatively wide, flat area on the hinge plate.

The shell of S. falcata Gould, originally described
from Puget Sound is thinner, decidedly more inequila-
teral and more attenuated anteriorly than S. planulata,
and the right anterior accessory lamina on the hinge is
nearly in line with and only slightly separated from the
ventral lateral.

The shell of the generally more southern species,
Spisula dolabriformis Conrad is more attenuated anter-
iorly than that of S. planulata, the anterior dorsal margin
beneath the beak is more projecting, on the adult shells
there is a narrow radial depression anterior to the poster-
ior angulation, and the pallial sinus is wider.

Spisula planulata, S. falcata, and S. dolabriformis
appear to be related species and have been discussed by
Burch (1183) and by Hertlein and Strong (1184). Many
of the records of the occurrence of S. planulata in beds
earlier than Pleistocene in age need confirmation.

Another member of this group of species is Spisula
strongi Burch (1185) which was described from Newport
Bay, California. Through the courtesy of Dr. Harald A.
Rehder we were able to examine the type specimen of
that species. It is 52.2 mm long, 34.6 mm high, convexity
(both valves together) 17.3 mm, and the pallial sinus ex-
tends forward 22.2 mm from the posterior end of the
shell. The outline of the shell is similar to that of S. dola-
briformis of the same size. The hinge of S. strongi differs
from that species, as mentioned by Burch, in that it lacks
what he designates as a proximal anterior lateral tooth ad-
jacent to the cardinal teeth and there is but one anterior
lateral on the right valve.

The shell of S. planulata is more highly trigonal in
outline than that of S. strongi. Furthermore, a proximal
anterior lateral tooth is present on the hinge of the left
valve and there are two well developed laterals on the
right valve.

GENUS TRESUS GRAY

Cryptodon Conrad, Jour. Acad. Nat. Sci.
Vol. 7, Pt. 2, P. 235, 1837. Sole species:
Conrad.

Not Cryptodon Turton, 1822, nor Cryptodon Latreille,
1833.

Tresus Gray, Ann. Mag. Nat. Hist., Ser. 2, Vol. 11, p. 42,

Philadelphia,
“L. nutallii”

317
January, 1853. Sole species: “‘T. maximus.” [Preceding
the description of the genus, Gray mentions “‘Lutraria

sp., Middend.”] — Keen, Veliger, Vol. 4, No. 4, p. 179,
1962. “‘type species, by monotypy, Lutraria maxima
Middendorff, 1849 [non Jonas, 1844] L. nuttalli Con-
rad, 1837”...

Not Trésus Walckenaer, Ann. Soc. Enotomol. de France,

Tome 2, p. 438, October, 1833. Arachnida. [No
species cited. A virtual nomen nudum.]
Schizothaerus Conrad, Proc. Acad. Nat. Sci. Philadel-

phia, Vol. 6, p. 199, January, 1853 [issued February
7, 1853, according to A. M. Keen]. Sole species:
Schizothaerus nuttallii Conrad. — Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 404, 1931.
Type: Schizothaerus nuttallii Conrad.

Type species (by monotypy). — Tresus maximus
[Middendorff] [=Lutraria maxima Middendorff, Beitrage
zu einer Malacozoologia Rossica (from Mém. Sci. Nat.
Acad. Imper. Sci. St. Petersbourg, Ser. 6, Vol. 6), Pt. III,
p. 66, pl. 19, figs. 1-4, 1849. ‘“‘Fundort: Die Insel Sitcha
(Wosness.)”” Not Lutraria maxima Jonas, 1844).

Range. — Middle Miocene to Recent: Recent from
Japan to Lower California, from the intertidal zone to 46
meters (25 fathoms).

Original description. — Shell ovate, oblong, ventri-
cose, hinder gape roundish; cardinal teeth small, lateral
teeth very small, close to the cardinal; siphonal inflection
large, oblong. (Gray.)

Remarks. — The generic name Tresus Gray apparent-
ly was published about a month earlier than Schizothaerus
Conrad, as mentioned by Dall in 1909. However, Dall re-
tained usage of the name Schizothaerus because of Trésus
Walckenaer, 1833. Keen (1962) presented evidence to
justify the replacement of Schizothaerus by Tresus Gray
and this procedure has been generally accepted by authors.

Tresus Walckenaer was published in a key in a class-
ification of arachnids. In this key it appeared with Myr-
mecia [Walckenaer, 1836], Platiscelum [ Audouin, 1826],
and Attus [Walckenaer, 1805] and a brief statement,
“Voltigeuses. Sautant et voltigeant avec agilitié pour att-
raper leur proie”’, applied to all four genera. Trésus is not
mentioned elsewhere in the text and no species was
assigned to it.

The usage of an accent mark does not indicate that
name was used in a vernacular sense as believed by some
workers. Such accent marks were used by others, for ex-
ample, Gray (1186) mentioned “‘Mactra grandis’’, ““Spisula
elongata” and others.

Keen considers Trésus of Walckenaer to be a nomen
nudum and it may be so interpreted because the particu-
lar descriptive material in the key applies to four genera.
However, it would be desirable that the Internat. Comm.
on Zool. Nomencl. Rule on the taxonomic status of Walc-
kenaer’s genus.

In view of the questionable taxonomic validity of
Trésus Walckenaer we use Tresus Gray in the present
paper.

The name Schizothaerus (1187) was applied to this
genus by Conrad “‘In allusion to the profound channel
which idents the hinge of both sides of the cardinal
teeth.” The general shape of the shell of this genus, ob-
long and gaping, is probably the result of the burrowing
habit of the animal.

Two and perhaps three species are known to occur

318

in late Tertiary beds in western North America and one or
two in Kamtschatka and Japan. Two Recent species are
usually recognized in the fauna of western North America
and one or possibly two in Japan and the North Pacific.

Tresus nuttallii Conrad
Plate 54, Figure 11; Plate 55, Figures 9, 13, 14, 17

L[utraria]. Nuttallii Conrad, Jour. Acad. Nat. Sci. Phil-
adelphia, Vol. 7, Pt. 2, p. 235, pl. 18, fig. 1, 1837.
(Under subgenus Cryptodon.)

Schizothaerus nuttallii Conrad, Proc. Acad. Nat. Sci. Phil-
adelphia, Vol. 6, p. 199, 1853. — Packard, Univ. Calif.
Publ. Bull. Dept. Geol., Vol. 9, No. 15, p. 266 (in
text), pl. 35, figs. la, 1b, 1916. Recent.—Packard,
Univ. Calif. Publ. Zool., Vol. 14, No. 2, p. 283, pl. 28,
figs. la, 1b, 1918. “Kodiak Island to Todos Santos
Bay, Lower California.”—I.S. Oldroyd, Publ. Puget
Sound Biol. Sta., Vol. 4, p. 60, pl. 33, figs. la, 1b,
1924. “Wrangell, Alaska, to San Diego, Calif.” Recent.
— I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol.
Sci., Vol. 1, p. 196, pl. 31, figs. 1a, 1b, 1924. “Wran-
gell, Alaska, to San Diego, California. In the Pleisto-
cene at Santa Barbara and San Diego, and the Pliocene
at Santa Barbara, California.”” —Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 404, pl. 22, fig. 9;
pl. 23, figs. 8a, 8b, 9, 1931. Late Miocene to Recent.—
J.Q.Burch, Min. Conch. Club South. Calif., No. 44, p.
22, five figs. (on pp. 23-24), 1944. “Bolinas, Calif. to
Scammon’s Lagoon, Lower Calif.”” Recent.—Swan and
Finucane, Nautilus, Vol. 66, No. 1, pp. 19-25, pl. 2,
1952. “extends at least as farnorth as 48°N.” (p.23).—
Fitch, State Calif. Dept. Fish Game, Mar. Fish Branch,
Fish Bull. No. 90, p. 89, fig. 55, 1953. ““Range: Puget
Sound to Scammons Lagoon, Baja California,” Recent.

Tresus nuttalli Conrad, Moore, San Diego Soc. Nat. Hist.,
Occas. Paper 15, p. 70, pls. 33, 34, 1968. San Diego
region, Pleistocene. Also Miocene to Recent in Calif-
ornia.

Type specimen. — Holotype No. 61.5.30.134, Brit-
ish Museum (Natural History) (A. M. Keen, Veliger, Vol.
8, No. 3, p. 170, 1966).

Type locality. — “‘Inhabits salt marshes, bare at low
water, in the vicinity of Sta. Barbara.’ [ California. |

Range. — Late Miocene (Briones Formation) to Re-
cent. Recent, Wrangell, Alaska (Dall), to Seammon’s La-
goon, Lower California, Mexico; in bays, estuaries, es-
teros and sheltered areas on the outer coast, from high
tide line to 46 meters (25 fathoms).

Occurrence in the San Diego Fm. — C.A.S. Loc.
1402. L.A.M. Loc. 107, 305, 305A, 309. S.D. Loc.
408, 417. U.C.L.A. Loc. 1383, 2420.

Original description. — Shell elliptical, slightly gibb-
ous from beak to base; posterior side produced; ligament
margin slightly declining, rectilinear, extremity obliquely
subtruncated; umbo prominent; colour white; epidermis
very thin, brown, wrinkled on the margins. Length, six
inches. (Conrad.)

Remarks. — Tresus nuttallii is represented in the
collections from the San Diego Formation by a number of
specimens, mostly single valves and hinges in various
states of preservation. The largest specimen is a left valve

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

from Loc. 305 (LAM), near the Mexican Boundary. It is
150 mm long (posterior end incomplete) and approx-
imately 112 mm high. A smaller specimen, both valves,
from Loc. 2420 (UCLA), from Pacific Beach is 110.6
mm long, 74.6 mm high, convexity (both valves to-
gether, separated by about 3 mm) 51 mm. All the shell
characters of these fossils are similar to those of Recent
specimens from adjacent waters.

A large Recent specimen from Loc. 4649 (CAS),
collected at San Diego, is 162 mm long, 98 mm high, con-
vexity (both valves together) 71.5 mm; the pallial sinus
extends forward and gently downward 94 mm from the
posterior end of the shell. A huge Recent shell (1188)
from Vaughan Bay, Washington, was reported to be 206
mm long and 139 mm high. This species also occurs else-
where in Pliocene strata at various localities in California.

The shell of Tresus nuttallii is larger, longer, more
ventricose, the anterior end is longer and the posterior
gape is more rounded than that of Tresus pajaroanus Con-
rad (1189), a Pliocene species originally described from
strata now considered to be referable to the Purisima
Formation.

Three names for Recent West American species re-
ferable to Tresus were proposed subsequent to the des-
cription of T. nuttallii. Lutraria maxima Middendorff
1849 (1190), (not Lutraria maxima Jonas 1844), (1191),
from Sitka, Alaska, is referable to Lutraria capax Gould
1850, (1192) from Puget Sound and Lutraria inflata Dun-
ker 1853, (1193) described from California, believed to
be a synonym of T. nuttallii.

Swan and Finucane (1194), made a careful study of
Tresus nuttallii, also the rounded form, 7. capax, which
they considered to be a distinct species. They concluded
that the adults of the rounded northern form are usually
readily separable from nuttallii, that it usually burrows
less deeply in more compact mud and gravel mixtures,
that it withstands lower temperature, and that there are
differences in the details of the animals of the two spec-
ies. More recently Pearce (1195) also presented evidence
to indicate that the two are separate species. Pholo (1196)
described the changes of form and mode of life of T.
nuttallii.

The name Schizothaerus nuttallii bighopensis was
proposed by Henderson (1197) for a fossil form of
Pleistocene age, from Big Hope Island in Puget Sound.
This form, according to Henderson, differs from the
rounded form described as Lutraria capax by Gould in
“being invariably thick, very coarse and rough, propor-
tionately higher and the beaks more nearly central than
in any recent material | have seen from there or else-
where.”

A species occurring in Japanese waters, often re-
ferred to Schizothaerus nuttallii was later described as
Schizothaerus keenae by Kuroda and Habe (1198). The
shell of the Japanese species is higher and the posterior
truncation is broader than that of T. nuttallii. An ex-
tensive discussion of the habitat of this clam was pub-
lished by Cahn (1199). A Miocene fossil in Japan, Schizo-
thaerus nuttallii kissyuensis Hatai (1200), was described
prior to S. keenae and the latter needs comparison with
the fossil form.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

ORDER ASTHENODONTIDA DALL
SUPERFAMILY MYACEA GOLDFUSS
FAMILY MYIDAE GOLDFUSS (1201)

Burrowers in sand or mud, sometimes nestlers,
usually with elongated or ovate, subequal valves but
often irregular or distorted in nestling forms, the surface
white, earthly or chalky, often with coarse concentric
growth sculpture and a covering periostracum. Ligament
mostly internal; in the left valve, the resilium is attached
to a large projecting arm or chondrophoral plate, the res-
ilifer being a rounded or sagittate scar bordered above and
behind by a small ridge (nymph); this chondrophoral
arm fits into a deep pit in the beak of the right valve,
the scar of the resilifer is placed in the roof of the um-
bone within, while above it on the posterior margin of the
within, while above it on the posterior margin of the
valve, there is a smaller scar to which the external portion
of the ligament (tensilium) is attached. Hinge margin
with or without teeth. Internal margins of valve smooth.
Pallial sinus present or wanting. (Olsson, Mollusks of the
Tropical Eastern Pacific. (Paleo. Res. Inst.: Ithaca, New
York), p. 422, 1961.) Paleocene to Recent.

Remarks. — Four genera of the family Myidae are
represented in the Pliocene of California, two of which
occur in the San Diego Formation. In general, the mem-
bers of this family live in shallow (low water to 50 met-
ers, rarely to 265 meters), boreal and temperate waters
where they burrow in muddy bottoms or nestle in
cavities. Lamy (1203) published a revision of the members
of this family represented in the collection of the Natural
History Museum in Paris.

The genus Mya has not been reported from the San
Diego Formation but it is represented from Miocene to
Recent in strata along the northeastern Pacific. A subgen-
us Antiguamya Effinger (1204) was described from the
Gries Ranch beds of early Oligocene age in western
Washington.

A paper by Fujie (1205) contains an account of the
genus Mya and its species in Japan. More recently, a
paper by MacNeil (1206) contains a thorough discussion
of the evolution and distribution of Mya.

Key to Genera of Myidae

A. Pallial sinus large and

broadly rounded . Sphenia
B. Pallial sinus very short
or lacking . . Cryptomya

GENUS CRYPTOMYA CONRAD

Cryptomya Conrad, Proc. Acad, Nat. Sci. Philadelphia,
Vol. 4, p. 121, December, 1848. Sole species, Sphaenia
californica Conrad. — Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 416, 1931. Type (by mono-
typy): Sphaenia californica Conrad. — Olsson, Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.:

319

Ithaca, New York), p. 423, 1961. Type by monotypy.

Type species (by monotypy). — Sphaenia cali-
fornica Conrad.

Range. — Late Oligocene (San Ramon) or early
Miocene, to Recent. Recent from the littoral zone to 91
meters (50 fathoms).

Description. — Shell small, ovate, slightly gaping
posteriorly; similar to a small Mya from which it differs in
that the pallial sinus is very short or lacking; chondro-
phore similar to that of Mya arenaria.

Remarks. — The shells of the species of this genus
are somewhat variable in shape and this variability has
led to the description of a number of species based upon
rather slight differences.

Lamy (1207) discussed the Recent species of this
genus in the collections of the National Museum of Nat-
ural History in Paris. Beets (1208) in 1950 cited ten spec-
ies occurring as fossils, with the range of the genus from
Miocene to Recent. There may be additional species, for
his list lacks references to two fossil forms described in
western North America, Cryptomya incognita Clark,
from the San Ramon Formation, referred to late Oligo-
cene age, and C. quadrata vancouverensis Clark and Arn-
old from the Sooke Formation, of late Oligocene or early
Miocene age. In Japan and the East Indies this genus is
known to occur from Miocene to Recent. Recent species
have been reported from west Mexico to the East Indies
and one species from the Red Sea and Australia. Vena-
tomya Iredale (1209) was proposed as a genus with the
Australian species, “type Sphaenia elliptica A. Adams.”

Key to Species and Subspecies of Cryptomya

A. Maximum length about 37 mm;
umbos usually gently. inflated californica
B. Maximum length about 48 mm;
umbos usually moderately

inflated . (subspecies) magna

Cryptomya californica Conrad
Plate 55, Figures 3, 4, 7, 16

S[phaenia]. californica Conrad, Jour. Acad. Nat. Sci.
Philadelphia Vol. 7, Pt. 2, p. 234, pl. 17, fig. 11, 1837.
Cryptomya californica Conrad, Dall, Proc. Calif. Acad.
Sci., Vol. 5, p. 296, 1874. “Well at San Diego.” “Plio-
cene.—Dall. Proc. U.S. Nat. Mus., Vol. 1, p. 28, 1878.
Well at San Diego.—Cooper, Calif. State Min. Bur.,
Seventh Ann. Rept. State Mineral., p. 237, 1888.
“Pl. — . . . San Diego well.’”? — Orcutt, West Amer.
Sci., Vol. 6, whole No. 46, p. 85, August 1889. Dall’s
record (1874) cited. — Arnold, Mem. Calif. Acad. Sci.,
Vol. 3, p. 180, 1903. Cooper’s record (1888) cited. —
Orcutt, cited by Ellis in Ellis and Lee, U.S.G.S.,
Water Supply Paper 446, p. 59, 1919. Dall’s record
(1874) cited. — Hertlein and Grant, Mem. San Diego
Soc. Nat. Hist., Vol. 2, Pt. 1, p. 48. Dall’s record
(1874) cited.—Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 423,

320

pl. 77, figs. 2, 2a, 1961. Alaska to Bayovar, Peru.

Mya (Cryptoma) californica Conrad, Packard, Univ. Calif.
Publ. Zool., Vol. 14 No. 2, p. 284, pl. 31, figs. 2a, 2b;
pl. 53 (chart, distribution), 1918. Numerous localities
in and near San Francisco Bay, California. “Range. —
Chichagoff Island, Alaska to Topolobampo, Mexico
(Dall).””

Type specimen. — Location unknown to the present
authors.

Type locality. — “Inhabits salt marches, near Sta.
Barbara; rare.”

Range. — Late Miocene (Briones Formation) to Re-
cent. Recent from Chichagoff Island, Alaska, to Bayovar,
Peru. Along the beach in a zone just below Heterodonax
bimaculatus Linnaeus (J.Q. Burch) (1210).

Occurrence in San Diego Fm. — San Diego well
(Dall). L.A.M. Loe. 305.
Original description. — Shell suboval, convex-de-

pressed, with radiating striae; obscure, except towards the
posterior extremity, where they are distinct; posterior
margin obliquely truncated, rectilinear; beaks central,
ligament margin arcuate; tooth much dilated, oblique;
colour white, palleal impression without a sinus, but
forming a right angle posteriorly. (Conrad.)

Remarks. — Cryptomya californica was reported
from the San Diego well by Dall in 1874. Apparently the
later published records of the occurrence of this species in
the San Diego Formation are based on that of Dall.

A number of valves here referred to C. californica,
most of them fragmental, were collected by G. P.
Kanakoff near the Mexican boundary. The largest one is a
right valve, 16.2 mm long, and 13.3 mm high. Several
valves are rather highly convex, probably as a result of the
habitat.

Several small casts in the collections of the San
Diego Society of Natural History lacking information as
to the locality from which they came, might be referable
to this species, but their small size and imperfect preserva-
tion are such that it is uncertain whether they should be
referred to this species or to the subspecies C. californica
magna.

The shell of this species is variable in outline and
several other species described from the late Tertiary of
western North America may be identical or at most sub-
species of Cryptomya californica. A Recent specimen of
average size from San Diego, collected by Frank Kelsey, is
31.8 mm long, 23 mm high, convexity (both valves to-
gether). 12.6 mm. A very large, somewhat quadrate speci-
men collected by Henry Hemphill at Tomales Bay, Calif-
ornia, is 37 mm long, 29 mm high, convexity (both valves
together) 15 mm. Grant and Gale placed six taxa in the
synonymy of this species but we consider at least one of
these, C. magna, to be a separate subspecies.

Cryptomya incognita Clark (1211) from the San
Ramon Formation in Contra Costa Co., California
appears to be a relative of C. californica but it is smaller
and the chondrophore is said to differ in that there are
two ridges bounding the resilium pit posteriorly rather
than one.

Two other species of Cryptomya have been des-
cribed from beds of Pliocene age in California and Oregon.
Cryptomya quadrata Arnold (1212) was described as
differing from C. californica by the more rectangularly
truncated posterior end, less sloping dorsal margins and in

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

the greater size. Cryptomya oregonensis Dall (1213) was
described as differing from C. californica by its subrhom-
bic shape. Some authors have placed the Oregon species
in the synonymy of C. californica but more recently
Weaver (1214) treated it as a valid species.

Cryptomya californica occurs at the present time
along western North America in shallow water both in
sheltered bays and along the open coast. MacGintie
(1215) mentioned that it may inhabit burrows of certain
species of crabs to a depth of 51 cm (20 inches). J.Q.
Burch mentioned that empty shells were dredged to
depths of 18, 27, and 91 meters (10, 15, and 50 fathoms),
and Yonge discussed the structure and adaptations of
this species (Univ. Calif. Publ. Zool., Vol. 55, No. 6, pp.
395-400, figs. 1-4, 1951).

This species has been reported living in Japan but
according to Habe (1216) the oriental species is refera-
ble to Cryptomya busoensis Yokoyama.

Cryptomya californica magna Dall
Plate 54, Figures 10, 13;
Plate 55, Figures 8, 10, 12

Cryptomya magna Dall, West Amer. Sci., Vol. 19, No. 2,
p. 17, April 27, 1921.—Dall, Proc. U.S. Nat. Mus., Vol.
66, Art. 17, No. 2554, p. 15, pl. 13, figs. 3, 4, Septem-
ber 22, 1925. “Pliocene (?) of San Quintin Bay,
Lower California.”” — Manager, Johns Hopkins Univ.
Stud. Geol., No. 11, p. 293, 1934. San Quintin Bay,
Lower California, Pleistocene.

Type specimen.—No. 333127, United States Nat-
ional Museum.

Type locality. — “San Quintin Bay, Lower Cali-
fornia .. . . late Pliocene or early Pleistocene ..... a

Range. — Middle Pliocene (San Diego Formation);
Pleistocene (San Quintin Bay), Lower California, Mexico.

Occurrence in San Diego Fm. — C.A.S. Loc. 1402.
L.A.M. Loc. 305, 305A, 319. S.D. Loc. 29. U.C.L.A.
Loc. 312, (cf) 1386.

Original description. — Shell oval, inflated, thin,
nearly equilateral and equivalve, sculptured only with ra-
ther prominent incremental lines; beaks low, nearly cen-
tral, posterior end very slightly more attenuated than the
anterior end; hinge with a very large receptacle for the
ligament with a strong ridge at the anterior and posterior
edges; a small anterior lateral in the left valve, right valve
edentulous; posterior muscular scars larger than the anteri-
or; pallial sinus almost obsolete. Length 35; height 24;
diameter 17 mm. (Dall.)

Remarks. — Several well preserved specimens from
Balboa Park in San Diego agree in shape and size with
the form described by Dall as Cryptomya magna. The
only feature mentioned in his original description which
we have not observed on the present fossils is an anterior
lateral tooth on the left valve. However, this is not shown
on his illustration of the type. We have examined speci-
mens of a Cryptomya from the type locality and we have
not observed any distinct anterior lateral on any of the
left valves.

The present fossils from the San Diego Formation
are much larger and more elongate than Recent specimens
of Cryptomya california. The largest specimen we have ob-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

served is a right valve from Loc. 29 (SD), Balboa Park,
San Diego, 48 mm long, 35.8 mm high (incomplete),
convexity (one valve) 9.4 mm. Nearly all the specimens
from Balboa Park attain a length between 40 and 45 mm.
The size and shape of these fossils differ from those of
Recent Cryptomya californica sufficiently to justify
subspecifie status for Dall’s Cryptomya magna.

One cast from Reynard Way in the collections of
the San Diego Society of Natural History appears to be
referable to this subspecies. Several small casts in the
collections of the same institution which lack information
as to the locality from which they came may perhaps be
referable to this form.

This is the first record of the occurrence of this
large subspecies from a locality other than the type
locality in beds of Pleistocene age at San Quintin Bay,
Lower California.

GENUS SPHENIA TURTON

Sphenia Turton, Conchyl. Insul. Britannicum, pp. XVII,
36, 1822. Species cited, Sphenia binghami | Turton],
S. swainsoni Turton, S. decussata [Montagu]. — Coss-
mann and Peyrot, Act. Soc. Linn. Bordeaux, Tome 63
(Conch. Néog. L’Aquitaine, Tome 1), p. 87, 1909.
“G. - T.: S. Binghami Turton.” — Lamy, Jour. de Con-
chyl., Vol. 70, No. 3, p. 176, 1927. ‘‘dont le type est
S. binghami Turt.”” — Olsson and Harbison, Acad. Nat.
Sci. Philadelphia, Monogr. No. 8, p. 149, 1953. ““Type
by subsequent designation, Gray, 1847: S. binghami
Turton.”

“Spaena Turton” and “‘Sphaenia Turton” of authors.

Type species (by subsequent designation, Gray,
Proc. Zool. Soc. London for 1847, p. 190). — “Sp.
Binghami” | Turton, Conchyl. Insul Brit., p. 361, pl. 3, figs.
4, 4; pl. 19, figs. 3, 1822. ““Rocks in Torbay.” Also illus-
trated by H. and A. Adams, Gen. Rec. Moll., Vol. 2, p.
357, 1856, pl. 95, figs. 4, 4a, 4b, 1855. — Tryon, Struct.
and Syst. Conch., Vol. 3, pl. 105, fig. 96, 1884. Europe.—
Lamy, Jour. de Conchyl., Vol. 70, No. 3, p. 178, two figs.
(p. 176), 1927. For a discussion of this species see Yonge,
C.M., “Observations on Sphenia binghami,”’ Jour. Mar.
Biol. Assoc. U.K., Vol. 30, No. 3, pp. 387-392, 2 figs. in
text, 1951.]

Range. — Paleocene to Recent. Recent, widespread,
from intertidal zone to 393 meters (215 fathoms), most
abundant in cool and temperate waters.

Description. — Shell generally small, inequivalve,
elongate, usually irregular because of a nestling habit.
External surface marked only with irregular growth-lines
sometimes divided into resting stages. Hinge teeth absent.
Left valve with an elongate, flattened chondrophore
which extends or fits obliquely under the umbonal mar-
gin of the right valve. Pallial sinus large and broadly
rounded. (Olsson and Harbison.)

Remarks. — Three species attributed to this genus
(one doubtfully) have been reported from strata of Terti-
ary age in California. Five species are reported to be
living in waters between Alaska and San Diego, California,
and at least three species have been described from tropi-
cal west American waters.

The genus Sphenia is reported here for the first

321

time from the San Diego Formation. One species, Sphenia
ef. S. globula Dall was reported by Woodring from the
Foxen Mudstone of Pliocene age in the Santa Maria
district in Santa Barbara Co.

E. A. Smith (1217) discussed the genus Sphenia in
which he included ten Recent species. Lamy, 1927, also
discussed this group of pelecypods.

Sphenia cf. S. luticola Valenciennes
Plate 56, Figures 21, 22

The following are references to typical S. luticola.
Corbula luticola Valenciennes, Zool. Voy. Venus, Atlas,
Moll., pl. 24, figs. 6, 6a, 1846 [No locality cited.]
Sphaenia fragilis Carpenter, Cat. Mazatlan Shells Brit.
Mus., p. 24, August, 1855. — Carpenter, Rept. Brit.
Assoc. Adv. Sci. for 1863, p. 543, issued August,
1864. Reprint in Smithsonian Mise. Coll., No. 252, p.
29, 1872.—Brann, Illustrations to “Catalogue of the
Collection of Mazatlan Shells’? by Philip P. Carpenter
(Paleo. Rest. Inst.: Ithaca, New York), p. 12, pl. 5, fig.
35; pl. 6, fig. 35, 1966. — Keen, Veliger, Vol. 10, No.

4, p. 400, text fig. 22, 1968.

Sphenia fragilis Carpenter, de Folin, Les Méléagrinicoles
(Havre), p. 15, pl. 2, figs. 7, 9, 1867. — E. A. Smith
Ann. Mag. Nat. Hist., Ser. 6, Vol. 12, p. 279, pl. 154A,
figs. 4, 5, 1893. ‘“‘Hab. Mazatlan, west coast of Mex-
ico.”— Lamy, Jour. de Conchyl., Vol. 70, No. 3, p.
179, 1927. ‘‘Californie.’—K.V.W. Palmer, Geol. Soc.
Ame., Mem. 76, p. 116, 1958. Earlier records of range
cited. — Franc, Traite de Zool., Vol. 5, Fase. 2, p.
2150, fig. 1801 E (p. 2121), 1960. — Olsson, Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 424, pl. 77, figs. 9, 9a, 9b, 1961.
““Venado Beach, Panama Canal Zone.”’ Range: “‘Ore-
gon ? to Northern Peru.”

Type specimen of Corbula luticola. — Muséum
Nationale d’Histoire Naturelle, Paris. Type material of
Sphenia fragilis is also in the British Museum (Natural
History) (see Lamy, 1927, p. 180).

Type locality. — No locality originally cited for
Corbula luticola. Of Sphenia fragilis, ““Hab. — Mazatlan:
inhabiting the burrows of worms and Mollusks in Chamae
and Spondylus Lamarckii; also in dead Balani on Strom-
bus galea; not uncommon; L’pool & Havre coll.”

Range. — Oregon?; California to Zorritos, Peru.

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Original description of Sphenia fragilis. — S. ani-
mali in cryptis latibulante, ergo ovarie distorto; testa parva,
tenui, subnacrea, vix rugose striata; epidermide fusco-
virente copiose induta, regarum increscentium concen-
tricarum plena, postice in siphone longa porrecta: parte
postica plus minusva subearinata; valva sinistra dente lig-
amentum ferente, plus minusve seu prolongata seu ex-
tanta; dextra alveo conveniente, nonnunquam denticulo
subextante: impressionibus muscularibus subrotundatis,
sinu palii lato, rotundato, haud alto. (Carpenter.)

Largest specimen, Long. .18, Lat. .31, alt. .14
inches (Carpenter).

Remarks. — One left valve of a Sphenia about 4
mm long, was collected by George P. Kanakoff at Loc.
305 (LAM) near the Mexican boundary. A study of this

322

specimen leads us to refer it provisionally to Sphenia lut-
icola.

Carpenter in 1864 mentioned that his “Sphaenia
fragilis is perhaps S. luticola, Val.’’ Lamy, in 1927, stated
that an examination of two “‘specimens-types”’ of Corbula
luticola Valenciennes, 1846, confirmed Carpenter’s sug-
gestion that S. fragilis is identical with the species des-
cribed by Valenciennes.

Sphenia pacificensis de Folin (1218) is believed by
Keen (1219) to be only a more elongate form of S. frag-
ilis from Panama.

Olsson (1961, p. 423) mentioned that specimens in
the U. S. National Museum from Oregon and California
which are labelled Sphenia fragilis are much larger than
specimens of S. fragilis from the Panamic region. He sug-
gested that the northern shells may be referable to S.
trunculus Dall (1220) which is probably only a large form
of S. fragilis.

SUPERFAMILY CORBULACEA BOWDICH (1221)
FAMILY CORBULIDAE BOWDICH (1222)

The shell is small or medium size, rarely large, elon-
gately ovate, usually solid, the beaks generally submedian,
the anterior side rounded, the posterior side rostrated and
pointed at the end. The right valve is usually larger and
with stronger sculpture, the left valve may be similar, or
much smaller, with a more rounded outline, its surface
flat or depressed, and with finer or smoother sculpture.
The ligament is entirely internal, attached to an armlike
resilifer in the left valve, simulating a large tooth, which
fits into a deep socket-like resilifer in the right valve.
Hinge armature is variable but most Corbulas have a
single, large, hooked cardinal tooth in the right valve
placed in front of the resilial pit; there is a single car-
dinal socket in the left valve; lateral teeth are absent
in most groups. The pallial line is entire or it may carry a
small obscure posterior sinus. Surface covered with a per-
iostracum, sometimes heavy. [ Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New
York), p. 426, 1961.] Triassic to Recent.

Remarks. — A number of genera and subgenera of
this family have been described. A satisfactory assignment
of some of the species to the known supraspecific units
often offers difficulties.

Papers by Gardner (1223) and by Vokes (1224)
are an aid to anyone dealing with the Corbulidae. A cat-
alogue of the Recent species in the collections of the
Natural History Museum in Paris was published by Lamy
(1225).

GENUS CORBULA BRUGUIERE

{Corbula Bruguiére, Tabl. Encyclop. Méth. Vers Test.,Vol.
2, pl. 230, 1797. [Illustrations with genus name only,
no text or specific names.] — Lamarck, Syst. Anim. s.
Vert., p. 137, 1801. Species cited: Corbula sulcata, C.
laevigata, C. margaritacea, C. gallica, C. striata. —
Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ. No.
3, p. 286, 1930. Type species as designated by

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Schmidt, 1818, Corbula sulcata Lamarck.—Vokes, Bull.
Amer. Mus. Nat. Hist., Vol. 86, Art. 1, p. 7, 1945.
Type designated by Schmidt, 1818.—Olsson and Har-
bison, Acad. Nat. Sci. Philadelphia, Monogr. No. 8, p.
145, 1953. Type designated by Schmidt, 1818.

Not Corbula Roding in Bolten, Mus. Bolt., p. 184, 1798.
[ = Asaphis Modeer, 1793. ]

Aloidis Megerle von Muhlfeld, Ge. Naturfor. Freunde zu
Berlin, Vol. 5, p. 67, 1811. Species cited: Aloidis
guineensis. Ref. to “‘Linn. Syst. Nat. pag. 3287” and
“Chemn. Conch. 10.t.172.f.1670. 1671.” — Hertlein
and Strong, Zoologica, Vol. 35, Pt. 4, p. 236, 1950.
“Type (by monotypy): Aloidis guineensis Megerle von
Mihlfeld.”’ [ = Corbula sulcata Lamarck. |

Type species (designated by Schmidt, Versuch
Conch.-Samml., p. 77, 1818): — “Typ. Corbula sulcata.
Encyclop. tab. 230. Fig. 1. a. b. ec.’ [Lamarck, Syst.
Anim. s. Vert., p. 137, 1801. No locality cited. — La-
marck, Hist. Nat. Anim. s. Vert., Vol. 5, p. 495, 1818.
“Habite. . . .’Océan indien?’? — Illustrated by Reeve,
Conch. Icon., Vol. 2, Corbula, sp. 2, pl. 1, fig. 2, 1843.
“Hab. Senegal.”” — Vokes, 1945, p. 7 et seq., pl. 1, figs.
1-5. Senegal, Recent. |

Range. — Triassic?; Jurassic to Recent. Recent from
the intertidal zone to 2699 meters (1476 fathoms).

Description. — Shell inequilateral, inequivalve, the
right valve somewhat larger than the left, which it clasps
or overlaps along the ventral margin, solid, rostrated.
Right valve has a large anterior cardinal tooth in front of
a deep resilial pit and a smaller posterior lateral tooth.
Left valve carries a heavy hinge plate bearing a large, deep
cardinal socket, a smaller pit for the resilium behind it
(not a separate chondrophore plate), a rather large, knob-
like posterior cardinal, and a small posterior lateral soc-
ket. Sculpture of both valves of strong concentric rib-
lets. Both valves have a prominent umbo ending in an in-
curved beak, narrowly rostrated or pointed behind, the
rostral area forming a depressed or concave escutcheon-
like zone, bounded externally by an angle or keel running
from the beak to the posterior extremity of the shell.
(Olsson and Harbison.)

Remarks. — The use here of the genus name Cor-
bula is based upon the ruling of the Internat. Comm.
Zool. Nomencl. in 1950. In that ruling (1226) it was
stated that a genus name appearing on a plate but with-
out explanatory matter is to be considered as published
if it appeared prior to January, 1931. This is not a very
satisfactory solution because it leaves open to personal
opinion the identification of the species represented by
unidentified figures. The ruling, however, appears to be
clearly applicable to the name Corbula. If for any reason
the name Corbula should be abandoned, Aloidis Megerle
von Mihfeld would take its place.

Eames (1227) discussed the genus Corbula and con-
sidered Gray’s (1228) designation of Corbula sulcata to be
the first valid designation of type species of this genus
rather than that of Schmidt because the type designation
by the latter refers to Corbula of Lamarck. However,
most authors accept Schmidt’s earlier designation of the
same species as the type of Corbula.

There are between 75 to 100 Recent species which
have been assigned to Corbula or to subgenera allied to it.
These live in sand or mud in warm, often shallow waters
along the seashore or in estuaries although species have

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

been reported from depths exceeding 2000 meters. Most
of the species do not exceed 10 mm in length but some
attain a length of 30 mm or more.

SUBGENUS VARICORBULA GRANT AND GALE

Varicorbula Grant and Gale, Mem. San Diego Soc. Nat.
Hist., Vol. 1, pp. 12, 420, November 3, 1931.—Vokes,
Bull. Amer. Mus. Nat. Hist., Vol. 86, Art. 1, p.
12, 1945. Type designation by Grant and Gale cited.—
Olsson and Harbison, Acad. Nat. Sci. Philadelphia,
Monogr. No. 8, p. 147, 1953. “Type by original
designation: Corbula gibba (Olivi).”—Olsson, Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 438, 1961. Type as in preced-
ing reference.

Type species (by original designation). — “In case a
new name is needed for the gibba group, we propose
Varicorbula, with Corbula gibba (Olivi) as figured by
Bucquoy, Dautzenberg and Dollfus for the type.” [See
Bucquoy, Dautzenberg, and Dollfus, Moll. Mar. du Rous-
sillon, Tome 2, Fase. 11 (Pelecypoda, Fasc. 24), p. 578,
pl. 85, figs. 1-6 (typical), 7-23 (varieties), 1896. Med-
iterranean, Adriatic, Sea of Marmora; Atlantic Ocean
from Norway to the Canary Islands, Also Miocene to Re-
cent._Vokes, 1945, p. 8, pl. 1, figs. 11-15. “Recent.
Zetland, British Isles.”—Tebble, British Bivalve Seashells
[British Museum (Nat. Hist.)], p. 171, text fig. 91a, b, ¢,
1966. ]

Range.—Late Cretaceous (Maestrichtian) to Recent.
Recent from the intertidal zone to 2697 meters (1476
fathoms).

Description. — Shell small or of medium size, sub-
rounded and with strongly discrepant valves as to size and
sculpture. Right valve larger, higher, more convex, obtuse-
ly rostrated and slightly produced posteriorly, generally
sculptured with strong, concentric riblets. Left valve
smaller, flatter, subelliptical in form, its surface smoother,
and bearing a few irregularly distributed radial threadlets
on its ventral portion. Hinge: right valve, as in other
Corbulas, has a single large cardinal tooth in front of a
deep resilial pit; left valve with a small projecting chon-
drophore, its inner portion carrying a resilial scar,
bounded behind by an elevated lamella which may fune-
tion as a substitute tooth, and which fits into a small
depression along the posterior side of the resilial pit of
the opposite valve. (Olsson and Harbison.)

Remarks. — The shell of Varicorbula differs from
that of typical Corbula in the very fine sculpture on the
left valve which also often bears some irregularly spaced
radial threads on the ventral portion. Also the left valve
has a small, projecting chondrophore, a feature lacking on
the type species of Corbula.

Vokes, 1945, gave Varicorbula generic status and
placed it in a new subfamily, Caryocorbulinae, and this
was followed later by several authors. We follow the
more conservative course by treating it as a subgenus of
Corbula, at least until the systematics of the family Cor-

bulidae is more stabilized.

The similarity of Varicorbula to Notocorbula Ire-
dale (1229) was mentioned by Woodring (1230) and
later by Eames both of whom suggested possible relega-

323

tion of it to the synonymy of Iredale’s genus. The type
species of Notocorbula has a well developed rostrum
posteriorly and the cardinal tooth was described as
keeled. Vokes accepted Notocorbula as a valid genus but
did not suggest any close relationship to Varicorbula.

Yonge (1231) discussed the habits and adaptations
of the European species Corbula gibba, the type of Var-
icorbula. The development of sculpture of inequivalve
mollusks, including Corbula was discussed by McLean
(1232).

Corbula (Varicorbula) gibbiformis Grant and Gale
Plate 57, Figures 3, 4

Corbula (Corbula) gibbiformis Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 420, pl. 19, figs. 4, 5,
6, November 3, 1931.

Corbula (Varicorbula) gibbiformis Grant and Gale, Wood-
ring, U. S. G. S., Prof. Paper 190, p. 55, pl. 6, figs. 8,
9, 1938. “Great American Petroleum Co. Tuffree No.
2, East Coyote field, depth 3,351 to 3,356 feet; U. S.
G. S. locality 13873.’ — Woodring, et al., in Winterer
and Durham, U. S. G. S., Prof. Paper 334-H, p. 304,
1962. Pico Formation, north and south side of Santa
Clara River Valley.

Corbula gibbiformis Grant and Gale, Vedder, U. S. G.S.,
Prof. Paper 400-B, p. B327, 1960. ‘‘Niguel formation,”
also “Eastern Ventura basin.”

Type specimen. — No. 172, San Diego Society of
Natural History.

Type locality. — ‘Southern California Gas Comp-
any’s well No. 1-4, Sec. 4, T. 28 S., R. 23 E., Kern
County, depth 3951-2 feet, upper Etchegoin formation,
upper Pliocene.”

Range. — Middle Pliocene.

Occurrence in San Diego Fm. — U.C.L.A. Loc.
2359.

Original description. — Shell of medium size, trigo-
nal, plump; right valve strongly ventricose, with strong,
concentric, closely-spaced riblets, left valve smaller, more
elongate, with about five low, narrow, sharp radial rib-
lets; right hinge with one strong cardinal tooth beneath
the curved-over umbo and anterior to a prominent pit;
left valve with a pit and a low, tooth-like prominence
posterior to it. Length, about 13 mm.; height, about 13
mm. (Grant and Gale.)

Remarks. — Six specimens, mostly small, are pre-
sent in the collection from Loc. 2359 (UCLA). The larg-
est specimen, a right valve, is 14.9 mm long, 14.6 mm
high, convexity, 7.3 mm. All of these specimens have lost
some of the outer layer of the shell as a result of erosion.
Concentric sculpture is visible on some portions of larger
specimens and faint radial sculpture is visible on some of
the left valves. The hinge of the right valve bears a small
tooth similar to that shown in the figure of the paratype
(fig. 4) by Grant and Gale. The fossils from the San Diego
Formation appear quite similar to the illustrations of C.
gibbiformis published by Woodring. The state of preserva-
tion of the specimens is imperfect but their close resem-
blance to C. gibbiformis leads us to refer them to that
species. Specimens comparable to C. gibbiformis were ‘e-
corded by Stewart (1233) from the Pecten zone of the

324

San Joaquin Formation in the San Joaquin Valley.

Corbula gibbiformis bears considerable resemblance
to C. speciosa Reeve (1234), a tropical west American
species, but the Pliocene species apparently has more
regular, finer, concentric sculpture and a smaller tooth in
the hinge of the right valve. Furthermore, the fossils lack
the subquadrate shell development (nepioconch) which
forms the umbo of the right valve of C. speciosa for a dis-
tance of about 5 mm and then changes abruptly to coarse
rugose concentric sculpture. This early shell development
on C. speciosa has much the appearance of C. marmorata
Hinds.

Corbula nuciformis Sowerby (1235), another in-
habitant of tropical west American waters, resembles C.
gibbiformis in general outline but it is smaller, possesses
finer concentric sculpture and lacks radial sculpture on
the left valve. The same characters serve to separate C.
gibbiformis from C. granti Olsson (1236), described from
Pliocene beds in Costa Rica.

Another species cited by Olsson (1237) as “‘Corbula
(Varicorbula)cf. bradleyi Nelson” from beds of Pliocene
age in Panama, was said to differ from C. gibbiformis in
the less elevated form.

SUBGENUS LENTIDIUM CRISTOFORI AND JAN

Lentidium Cristofori and Jan, Catalogus, Section II*,
Conchyliologia, Pars 14, p. 8; Mantissa, p. 4, 1832.
Sole species: Lentidum ‘‘maculatum nob.” “‘Ital. bor.”
—Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p.
836, also 838, 1898. “Type Corbula mediterranea
Costa (+ maculatum Jan.).’’ — Vokes, Bull. Amer. Mus.
Nat. Hist., Vol. 86, Art. 1, p. 23, 1945. Type designa-
tion by Dall cited. :

Corbulomya Nyst, Mém. Cour., Acad. Roy. Sci. de Bel-
gique, Vol. 17, p. 59, 1844. Type (designated by Herr-
mannsen, Indic. Gen. Malacozoo., Vol. 1, p. 308,
1847): “Typus: Corbula complanata Sow.”’—Cossmann
and Peyrot, Act. Soc. Linn. Bordeaux, Tom. 63
(Conch. Néogén. |’Acquitaine, Tome 1, Livr. 1), p.
109, 1909. Designation of type species by Hermann-
sen cited.—See also Vokes, 1945, pp. 23, 24, 26.

Type species (by monotypy). — Lentidium macula-

tum Cristofori and Jan. [ Original description (Mantissa, p.

4): L? tests planata, striata, alba, maculis croceis picta

(lat. 2” long. 1 1/2”’).”’ Considered by Monterosato (Nom.

Gen. Spec. Conch. Mediterr., p. 30, 1884) and by Dall,

1898, to be referable to Tellina mediterranea O. G. Costa

(Cat. Test. Sicilie, p. XIV, pl. 1, fig. 6a, b, ce, 1829). Med-

iterranean, Recent. See Corbulomya mediterranea Costa,

Bucquoy, Dautzenberg, and Dollfus Moll. Mar. Rouss-

illon, Tome 2, Fase. 11 (Pelecypoda, Fasc. 24), p. 585,

pl. 85, figs. 24-29 (typical), 30-35 (varieties), 1896. Fora

thorough diagnosis of Lentidium mediterranea, see Vokes,

1945, pp. 23-24, pl. 4, figs. 23-27, 1945. “Recent. Genoa.

Italy.’’ |

Range. — Early Eocene (Thanetien) to Recent.
Original description of Lentidium. “Testa com-
pressiuscula subtriangularis, valvulis inaequalibus. Cardo
dente unico in utraque valvula, simplici in dextra, plicato
in sinistra. Liagmentum partim internum.” (Cristofori and
Jan, 1832, Mantissa, p. 4.)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Supplementary description. — Shell compressed,
trapezoid, feebly concentrically sculptured; the ligament
appearing externally through a fissure in the right umbo.
(Dall, 1898.)

Remarks. — The sole species listed under Lentidium
by Cristofori and Jan is L. maculatum although a number
of authors have cited Corbula mediterranea Costa [=Tell-
ina mediterranea O.G. Costa, 1829] as the type. It ap-
pears probable that the species described by Costa is
identical with the one described only briefly by Cristo-
fori and Jan as indicated by Monterosato and by Dall.
Bucquoy, Dautzenberg and Dollfus, however, did not
include L. maculatum in their synonymy of Corbulomya
mediterranea Costa.

Cossmann and Peyrot considered Corbulomya Nyst,
to be at least subgenerically distinct from Lentidium.
Most modern authors consider the two referable to the
same genus or subgenus and we follow that practice in the
present paper.

Vokes placed Lentidum as a genus in a new sub-
family Lentidiinae.

Corbula (Lentidium) luteola Carpenter
Plate 55, Figures 1, 2, 5, 6, 15

Corbula luteola Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, pp. 661, 637, issued August, 1864. P. 611,
“§.Pedro-S. Diego; common near shore.” P. 637, in-
dicated as from ‘‘The region between S. Diego and S.
Pedro.”’ Reprint in Smithsonian Mise. Coll., No. 252,
pp. 97, 123, 1872. — Carpenter, Proc. Calif. Acad.
Sci., Vol. 3, Pt. 3, p. 207, February, 1865. “Hab. —
San Diego, San Pedro, 50 alive at low water.” — I.S.
Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 203, 1924. “Monterey, California to Lower
California,” Recent. Also Pleistocene at San Pedro and
San Diego, and Pliocene at San Pedro, California.

Corbula luteola var. rosea Williamson, Bull. South. Calif.
Acad. Sci., Vol. 4, No. 8, p. 120, November, 1905.
“Valve on anemone in a rock pool on the old break-
water at Terminal Island,’ San Pedro, California.

Not Corbula rosea Reeve, Conch. Icon., Vol. 2, Corbula,
species 26, pl. 4, fig. 26, April 1844. ‘Hab. — ?”

Corbula (Lentidium) luteola Carpenter, Grant and Gale,
Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 421, pl. 19,
figs. 2, 7, 1931. Various localities cited. Late Miocene
to Recent.—Durham, Geol. Soc. Amer., Mem. 43, Pt.
2, p. 94, pl. 25, figs. 15, 16, 1950. Santa Ynez Bay,
Lower California, Pleistocene.—K.V.W. Palmer, Geol.
Soc. Amer., Mem. 76, p. 117, pl. 15, figs. 13-18, 1958.
[Earlier records cited. Type specimens discussed. ]

Alodis (Caryocorbula) luteola Carpenter, Hertlein and
Strong, Zoologica, Vol. 35, Pt. 4, p. 239, 1950. Mont-
erey, California, to Cape San Lucas, Lower California.

Corbula (Caryocorbula) luteola Carpenter, Keen, Sea
Shells of Tropical West America (Stanford Univ. Press:
Stanford, Calif.) p. 209, fig. 525, 1958. Southern Cal-
ifornia to La Paz, Lower California, Mexico.

Type specimen. — “‘Syntypes.—U. S. National Mus-

eum, no. 14897 (eight valves.’ (Palmer, 1958.)

Type locality. — “‘Recent. San Pedro, California

(type).” (Palmer, 1958.)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Range. — Late Miocene to Recent. Recent from
Monterey, California, to La Paz Lower California, Mexico,
from between tides to 46 meters (25 fathoms). Usually in
rocky rubble according to J. Q. Burch (Min. Conch. Club
South. Calif., No. 44, p. 29, February, 1945).

Occurrence in San Diego Fm. — L.A.M. Loc. 302,
305, 305A, 318, 319.

Original description. — “‘Shape of young biradiata;
small, ashy yellow. Com. Cp.” (Carpenter, 1864.)

Supplementary description. — C. t. “‘C. biradiatae’’,
forma simulante, sed multo minore; haud obesa, trans-
versa, luteo-conerea, dorsum versum interdum obscure
biradiata; angulo plus minusve carinato, postice definito;
antice rotundata, expansa; concentrice crebee sed obtuse
lirulata; umbonibus obtusis; intus, dentibus minoribus;
linea pallii angulata, haud sinuata; cicatricibus adduc-
toribus callosis; margine t. adulta postice altero alterum
amplectante. (Carpenter, 1865.)

Remarks. — Corbula luteola is here reported for the
first time from the San Diego Formation. There are about
40 single valves and one specimen with paired valves from
Loc. 305 (LAM) near the Mexican boundary. The largest
valve is 9 mm long and 5.7 mm high. The specimen with
both valves together is 8.1 mm long, 5.3 mm high, the
convexity (both valves together) 3.5 mm. A large Recent
specimen collected by Henry Hemphill at San Diego is
10.5 mm long, 7.2 mm high, the convexity (both valves
together) 4.3 mm, but most Recent specimens are smaller
than this one. A few single valves are present in the coll-
ections from Loc. 305A, 318 and 319 (LAM).

Corbula luteola has been compared with C. biradiata
Sowerby (1238) by several authors. Carpenter’s species is
smaller, generally more compressed, the posterior ventral
margin less acutely pointed and the coloration is dull gray
or buff.

SUPERFAMILY HIATELLACEA GRAY
FAMILY HIATELLIDAE GRAY (1239)
[SAXICA VIDAE GRAY]

Shell usually ovate or oblong, generally irregular due
to distortion, widely gaping behind, byssiferous. Surface
smooth but more often with irregular concentric riblets or
undulations. Hinge weak, the teeth often obsolete, no lat-
erals, the ligament external, attached to a strong nymphal
ridge. Pallial sinus of irregular size, the animal provided
with large siphons. Burrowing in deep sand, gravel, or as
nestlers or borers in rock. [ Olsson, Mollusks of the Trop-
ical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York)
p. 425, 1961.] [Late Jurassic to Recent. ]

Remarks. — The shells of this family vary greatly in
size. The animals are burrowing or nestling forms and, re-
flecting this habitat, their valves are gaping. There are two
small simple teeth in the hinge of the left valve and one in
the right. Their shells are usually sculptured only with
rude concentric ridges on the shell surface. Members of
this family often occur in the intertidal zone but some
have been reported to a depth of 448 meters. Kiihnelt
(1240) discussed the habitat of this group of mollusks
and White (1241) described the anatomy of ‘“‘Saxicava”
_ gallicana Lamarck.

A list of the species by Tryon (1242) and a revision
of the members of this family by Lamy (1243) are useful

325
in a study of this group.
Key to Genera of Hiatellidae
A. Shell with pallial line broken into an
irregular series of impressions.
a. Shell with a median radial
depression; roundly subquadrate,
nearly as high as long . Panomya
aa. Shell lacking a median radial
depression; rectangular, decidedly
longer than high . Hiatella
B. Shell with pallial line entire;
very large . Sy oe Panope

GENUS HIATELLA DAUDIN

Hiatella Daudin in Bose, Hist. Nat. des Coquilles, Vol. 13,
AN X [1801], p. 120. [This volume appeared prior to
October 23, 1801, according to Dodge, Bull. Amer.
Mus. Nat. Hist., Vol. 100 Art. 1, p. 33, 1952.] Species
cited: Hiatella biaperta and Hiatella monoperta. —
Iredale, Rec. Austral. Mus., Vol. 17, No. 9, p. 406,
1930. — Davies, Tert. Faunas (Thomas Murby and Co.:
London), Vol. 1, p. 201, figs. 169, 270, 1935. Paleo-
cene to Recent. Widespread. — Dodge, Nautilus, Vol.
64, No. 1, pp. 29-33, July, 1950. “The type of the
genus may be cited safely as H. biaperta Daudin + H.
monoperta Daudin, = Mya arctica Linné, by subjective
monotypy.” — Hertlein and Strong, Zoologica, Vol.
35, Pt. 4, p. 244, December 30, 1950. ‘Type (here
designated): Hiatella biaperta Bosc.”

Saxicava Fleuriau-Bellevue, Jour. de Physique de Chemie
d’Hist. Nat. et des Arts, Tome 54, AN X, p. 354, May
1802. Species cited: “La saxicave striée, saxicava
striata.” ‘Perce les rochers des cotes de la Rochelle.”
—Lamy, Jour. de Conchyl., Vol. 68, No. 3, p. 218,
1924. “qui a pour type S. striata Fl. = Mya arctica
2

Didonta Schumacher, Essai Nouv. Syst. Test., pp. 42,
125, 1817. Species cited: Didonta bicarinata Schum-
acher, p. 125, pl. 6, fig. 2. Ref. to Solen minutus
Linnaeus, Chemnitz, Neues Syst. Conchyl.-Cab., Bd.
6, p. 67, Tab. 6, figs. 51, 52, 1782. [= Mya arctica
Linnaeus. |

Type species (by subsequent designation, Dodge,
1950, p. 31, and Hertlein and Strong, 1950, p. 244). —
Hiatella biaperta Daudin in Bosc. Hist. Nat. des Coq., Vol.
3 AN X [1801], p. 120, pl. 21, fig. 2. “Se trouve sur la
cote de Tranquebar.”’ [ = Mya arctica Linnaeus. |

Range. — Paleocene to Recent. Recent world-wide,
chiefly in cool waters, from the intertidal zone to 2966
meters (1622 fathoms) usually burrowing or nestling in
cavities.

Description. — Shell small, irregular, very inequil-
ateral, the young with a cardinal tooth like Panomya, the
adult with the teeth obsolete; pallial line discontinuous,
siphons naked, slightly separated at the tips and in normal

326

specimens completely retractile, shell burrowing, or nest-
ling in gravel or broken shell, or perforating rocks, cor-
allines, or dead shells like pholads. (Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 4, p. 833, 1898.)

Remarks.—This genus has been reported occurring
from Paleocene to Recent. Whether or not it occurs in
older strata is not certainly known but the genus has been
cited, doubtfully, from strata of late Cretaceous age, in
Alberta, Canada (1244). Pseudosaxicava Chavan (1245)
described from beds of late Jurrassic age in France is be-
lieved to be an ancient member of the Hiatellidae.

On the west coast of North America, ‘‘Saxicava”’
Pholadis Linnaeus was reported by B. L. Clark from the
Poul Creek Formation in southern Alaska of late Oligo-
cene or early Miocene age. In California, the genus has
been reported from beds of middle and late Pliocene age
as well as in beds of Pleistocene age, and Recent. In Japan
species assigned to Hiatella have been reported from late
Oligocene or early Miocene (1246) to Recent, and in Aus-
tralia from Miocene to Recent.

Separation of the various species in some cases is
difficult because of the variation in the shape of the shell
which varies according to whether they burrow or they
nestle in cavities. Another problem in connection with
identification of these forms is whether some of them
should be assigned to Hiatella or to juvenile Panope.

Dodge (1950) discussed the problem connected
with the use of the names Hiatella and Saxicava. Dall
(1247) recently discussed the Hiatellidae and listed the
species referred to Hiatella.

Hiatella arctica Linnaeus
Plate 56, Figures 15, 17, 18

Mya arctica Linnaeus, Syst. Nat., ed. 12, p. 1113, 1767.
“Habitat in Oceano Norvegico.’’ — Hanley, Ipsa Linn.
Conch., pp. 28, 461, 1855. — Dodge, Bull. Amer. Mus.
Nat. Hist., Vol. 100, Art. 1, p. 31, 1952. [Discussion
of Linnaean species. }

Solen minutus Linnaeus, Syst. Nat., ed. 12, p. 1115,
1867. “Habitat in O. Norvegico. Martin.”—Chemnitz,
Neues Syst. Conchyl.-Cab., Bd. 6, p. 67, pl. 6, figs. 51,
52, 1782. Iceland; Greenland; Norway, Shallow and
deep water.—Hanley, Ipsa Linn. Conch., pp. 32, 462,
1855.

Hiatella biaperta Bosc, Hist. Nat. Coq., Vol. 3, AN X
[1801], p. 120, pl. 21, fig. 1. “Se trouve sur la cOtes
de Tranquebar.”’ [ India. |

Hiatella monoptera Bosc, Hist. Nat., Cog., Vol. 3, AN X
[1801], p. 120, pl. 21, fig. 1. “Se Trouve sur les cdtes
de Tranquebar.”’ [India].

Didonta bicarinata Schumacher, Essai Nouv. Syst. Test.,
p. 125, pl. 6, figs. 2 (a, b), 1817.

Hiatella arctica Linnaeus, Lamarck, Hist. Nat. Anim. s.
Vert., Vol. 6, p. 30, 1819. “‘Habite les mers du Nord,
dans le sable, et se rencontre parmi les fucus.’”’ — Hert-
lein and Strong, Zoologica, Vol. 35, Pt. 4, p. 244,
1950. Port Guatuleo, Mexico, to Piedra Blanca, Costa
Rica. Also Arctic Ocean to Panama, and Atlantic. —
Abbott, American Seashells (D. Van Nostrand Co., Inc.,
New York,), p. 452, fig. 92a, 1954. “Arctic Seas to
deep water in the West Indies. Arctic Seas to deep

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

water off Panama.’—Richards, Trans. Amer. Philos.
Soc., New Ser., Vol. 52, Pt. 3, p. 71, pl. 12 figs. 17-20,
1962. Hudson Bay to North Carolina, Pleistocene. Re-
cent: “Arctic to W. Indies in deep water. Arctic to
off Panama in deep water.”

Saxicava arctica Linnaeus, Sowerby, Reeve’s Conch. Icon.,
Vol. 20, Saxicava, species 1, pl. 1, figs. 1a, 1b, 1e, 1d,
1875. “Arctic regions, British and North American
coasts.” — Sars, Bid. Kunds. Norges Arkt. Fauna. I.
Moll. Reg. Arct. Norvegiae, p. 95, pl. 20, figs. 8a, 8b,
8c, 8d, 1878. Norway and Arctic regions. — Bucquoy,
Dautzenberg, and Dollfus, Moll. Mar. Roussillon, Vol.
2, Fase. 11 (Pelecypoda, Fasc. 24), p. 589, pl. 86, figs.
1-4 (typical); 5-11 (vars.), 1896. Various localities
cited.—I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 208, pl. 9, fig. 6; pl. 51, fig. 4,
1924. Arctic Ocean to Panama. Also Atlantic —Lamy,
Jour. de Conchyl., Vol. 68, No. 3, p. 222, 1924. Num-
erous localitites cited.

Type specimen. — ‘‘in the Linnaean cabinet” of the
Linnean Society of London (Hanley, Ipsa Linn. Conchyl.,
p. 28, 1855).

Type locality. — ‘‘Habitat in Oceano Norvegico.”

Range. — Oligocene to Recent. In western United
States, Pliocene to Recent. Recent, Arctic Ocean to Pan-
ama (in deep water); to the West Indies (in deep water);
northern Europe to the Mediterranean and west Africa.
From the intertidal zone to at least 1829 meters (1000
fathoms) and perhaps deeper, usually burrowing or nestl-
ing in cavities.

Occurrence in San Diego Fm. — L.A.M. Loc. 107,
305, 305C.

Original description.— M. testa striata: valvulis carin-
is duabus spinulosis; cardiae edentulo. Habitat in Oceano
Norvegico. F. Zoega. Testa magnitudine Fabae, rudis,
facie Arcae noae, pallida. Antice retuso-planiuscula, parte
anteriore obtusissima, posteriore breviore, acutiuscula;
pars anterior a natibus excurrit angulis duobus remotis
antrorsum subaculeatis. Cavitas interna lactea est. Cardo
vix ullus. (Linnaeus, 1767.)

Remarks.—The shell characters generally relied upon
to identify Hiatella arctica and H. pholadis (1248) were
summarized by Dodge (1952, pp. 32-33) as follows:

“Saxicava arctica: One tooth in the right valve and
two in the left. Roughly quadrate in form and longer in
proportion to width than rugosa. Spines on young or un-
worn specimens.” [See illustrations by Sars, 1878, and
Abbott, 1954.]

“Saxicava pholadis: A completely edentulous form.
The concentric sculpture is weaker than in either of the
others. Less quadrate than arctica. Spineless. More evenly
rounded at the ends than the other two.”

Hiatella arctica is here reported for the first time
from the San Diego Formation. Two right valves about 6
mm long are present in the collection from Loc. 305
(LAM); two valves, the larger one about 5 mm long, from
Loc. 305A (LAM); one small valve from Loe. 305C
(LAM); and one very small left valve from Loc. 318
(LAM). All these are from localities near the Mexican
boundary. A specimen with both valves from Loc. 107
(LAM) is 10 mm long.

The shell of this species is reported (Abbott, 1954)
to attain a length of 76 mm (3 inches). We have seena left
valve 68.5 mm long and 35.3 mm high which was taken

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

by R. R. Talmadge from a cavity in a sponge dredged off
Crescent City, Del Norte Co., California [Loc. 40733
(CAS)], in 750 meters (410 fathoms). Richards (1249)
pointed out in a discussion of Hiatella arctica that “the
heavy, coarse variety typical of the Pleistocene is limited
to Arctic and sub-Arctic seas.’’ Elton and Baden-Powell
(1250) mentioned that there appears to be a tendency for
the shell of H. pholadis to develop a thicker shell in the
colder waters of its distribution also a tendency to be
typically longer in warmer waters.

The species described as ‘“‘Saxicava’’ antarctica
Philippi (1251) is very similar to H. arctica and Dall
(1252) expressed doubt that the South American species
is distinct. We have noticed no difference, except in size,
between specimens referred to H. arctica from off Costa
Rica and those from boreal waters. Olsson (1253), how-
ever, believes it best to refer the Panamanian forms to H.
solida Sowerby (1254).

The type locality originally cited for H. solida was
Santa Elena, Ecuador. Dall (1255) stated that there is
doubt concerning this locality and he mentioned that
Sowerby in 1875 cited no locality for this species. He dis-
cussed (pp. 224-226) H. arctica and H. solida and con-
sidered the latter to be a species of southern South Amer-
ica but he mentioned that young shells of the two are in-
distinguishable. He observed that shells of H. arctica to a
length of 15 mm have well developed hinge teeth but that
these later become completely obliterated by an over-
growth of the nymph when 28 mm long whereas shells of
H. solida 20 to 35 mm long still retain obvious hinge
teeth. We have not had specimens from southern South
America for comparison but most specimens of H. arc-
tica 20 to 44 mm long which we have studied are vir-
tually edentulous.

Hiatella arctica was reported from Germany by von
Koenen (1256) from strata of middle Oligocene age and
by Gorges (1257) from beds of late Oligocene age. Coss-
man and Peyrot (1258) discussed its occurrence in beds of
Miocene age in France. They mentioned that records of
H. rugosa in beds of Miocene age are probably referable
to H. arctica but pointed out that H. vera Deshayes from
strata of Eocene age is a distinct species.

Many records of Hiatella arctica, subspecies such
as H. arctica bilineata Conrad (1259), and others cited as
H. arctica but later designated as distinct, such as H.
orientalis Yokoyama (1260), have been reported from
other parts of the world. The relationship of these various
forms must await a careful study of the group.

The present record of the occurrence of H. arctica
in the San Diego Formation is the earliest, geologically,
reported from California. Soper and Grant (1261) re-
ported this species from strata at Fifth and Hope streets
in Los Angeles, considered to be of late Pliocene age.

Dall (1262) reported H. arctica from several loc-
alities in southwestern Alaska from beds assigned Miocene
age. MacNeil (1263) later discussed these occurrences but
did not find specimens to verify the age assignment. Dall
(1264) also identified this species from beds probably of
Pliocene age, in Lituya Bay, in southeastern Alaska. It also
has been reported (1265) from the Daishaka Pliocene in
Japan.

Hunter (1266) discussed the boring habits of H.
arctica and more recently Ockelmann (1267) summarized
much information concerning this and similar forms.

327
GENUS PANOPE MENARD

Glycimeris Lamarck, Mem. Soc. Hist. Nat. Paris, Vol. 1, p.
83, 1799. Sole species, ““Mya glycimeris. Born. mus. t.
1 f.8:?

Not Glycymeris Da Costa, 1778.

Panope Menard de la Groye, Mémoire sur un nouveau
Genre de coquille bivalve-équivalve de la famille des
solenoides, pp. 16, 31, January, 1807. Two species
described, “‘P. Aldrovandi.”’, p. 31 (synon. included
Mya glycimeris Born), Recent, Europe, Mediterranean,
Spain; and “P. Faujas,” p. 33, pl. 12. “Se trouve foss-
ile en Italie, a six milles au sud de Plaisance, dans le
depot du Stramonte.” Also reported Recent in Med-
iterranean; Spain.—Dall, Proc. Malacol. Soc. London,
Vol. 10, Pt. 1, pp. 34-35, 1912.—Vokes, Jour. Paleo.,
Vol. 30, No. 3, pp. 766-777, 1956.

Panopaea Menard, Lamarck, Extr. Cours. Zool, p. 108,
1912. Type designated by Children (Quart. Jour.
Sci. Lit. and Arts., Vol. 14, p. 83, pl. 4, fig. 27, Octo-
ber, 1822): ‘“‘P. aldrovandi (Mya glycimeris Linn.)’’.

Type species (designated by Schmidt, Versuch
Conchyl.-Samml., p. 177, 1818). — “Type. Mya glyci-
meris’’ [Born, Index Mus. Caes. Vindobonensis, p. 10,
1778. No locality cited. (Ref. to Aldrovandi, Tes., 1. 9,
pp. 473, 474; Lister, Hist. Conch., 1. 3, fig. 258; Gualtieri
Test., t. 9 [90], fig. A.) — Born, Test. Mus. Caes. Vindo-
bonensis, p. 20, pl. 1, fig. 8, 1780. For references to and a
discussion of this species see Lamy, Jour. de Conchyl.,
Vol. 68, No. 4, pp. 267-269, 1925.]

Range. — Late Jurassic; Cretaceous to Recent. Re-
cent from the littoral zone to 165 meters (90 fathoms).

Description. — Shell usually large, elongated, ventri-
cose, anterior end rounded, posterior end truncated, gap-
ing (more so posteriorly); beaks subcentrally placed;
rather coarse concentric sculpture; hinge with one cardi-
nal tooth in each valve; ligamental ridge large; pallial sinus
well developed.

Remarks. — The earliest geologic occurrence of
Panope is not known with certainty because of the lack
of knowledge concerning the characters of the hinge
and other features of ancient species which may or may
not be referable to this genus. Panope brockworthensis
from the inferior Oolite, late Jurassic of England, was
described by Cox (1268) who discussed the difficulties
of determining the genera of many Mesozoic fossils. He
pointed out that some of those fossil forms might be
referable to the genus Myopsis L. Agassiz for which genus
he selected Mya mandibula Sowerby as type. Pleuromya
L. Agassiz, confined to the Mesozoic, has a smaller poster-
ior gape and a depression which extends from the umbos
to the anterior end and the shell is nacreous rather than
porcelaneous.

Five species of Panope have been recorded occurr-
ing in Tertiary strata of California. One Recent sub-
species of the California form has been described from
Scammon’s Lagoon, Lower California, and one species
from the Gulf of California. Others have been described
from the Cenozoic of South America.

Lamy (1269) published a useful summary of the
Recent species of Panope.

About a dozen Recent species of this genus occur
in the present seas mostly in cool and temperate water

328

but a few occur in subtropical waters. These mollusks
usually burrow in sandy mud which is exposed at low
tide.
Vokes (1270) discussed the name Glycimeris Lam-
arck (not Da Costa), an earlier name for Panope.
Deschaseaux (1271) placed Panope in the family
‘“‘Panopaeidae Zittel”’.

Panope generosa Gould
Plate 56, Figures 19, 20

Panopaea generosa Gould, Proc. Boston Soc. Nat. Hist.,
Vol. 3, p. 215, May, 1850. — Gould, U.S. Explor.
Exped (Wilkes), Vol. 12, Mollusca, p. 385, 1852,
Atlas, p. 13, pl. 34, figs. 507, 507a, 507b, 1856. —
J.P. Smith, Proc. Calif. Acad. Sci., Ser. 4, Vol. 3,
pp. 173, 182, 1912. “San Diego-Purisima. Pliocene.” —
I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol.
Sci., Vol. 1, p. 205, pl. 2, figs. 1, 2, 1924 (reproduc-
tion of Gould’s original figures 507a, 507b). ‘“‘Puget
Sound to San Diego, California.’’ Also Pleistocene and
Pliocene.

Panopea generosa Gould, Arnold, U.S.G.S., Bull, 396, p.
31, pl. 18, fig. 4, 1909. ‘““Upper Etchegoin formation.”
also Upper Miocene to Recent. Also Bull. 398, pl. 40,
fig. 4, 1910. (Same figure). — Reagan, Trans. Kansas
Acad. Sci., Vol. 22, p. 204, 1909. ‘‘Purisima-San
Diego”’ formation of California.

Panope genrosa Weymouth, Calif. State Fish Game
Comm., Fish Bull. No. 4, p. 63, pl. 18, fig. 2, 1920.
California coast.—I.S. Oldroyd, Publ. Puget Sound Biol.
Sta., Vol. 4, p. 63, pl. 16, figs. 1, 2, 1924. [ Reproduc-
tion of Gould, 1856, pl. 34, figs. 507a, 507b.] Van-
couver Island to San Diego, California.—Hertlein, Stan-
ford Univ. Bull., Ser. 5, No. 78, p. 82, 1929. ‘‘San
Diego Pliocene.’’—Fitch, Calif. Dept. Fish Game, Mar.
Fish. Branch, Fish Bull. No. 90, p. 92, fig. 58, 1953.
“Range: Forrester Island, Alaska, to Scammons La-
goon, Baja, California.”

Panope (Panope) generosa Gould, Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 424, pl. 21, figs.
12a, 12b, 1931. Miocene to Recent. [Not all the
synonymy. |

Panope (Panope) abrupta Conrad, Moore, San Diego Soc.
Nat. Hist., Occas. Paper 15, p. 42, pl. 19, 1968. Balboa
Park, San Diego, Pliocene.

Type specimen.—Holotype No. 5894, United States
National Museum.

Type locality. — “Hab. Puget Sound, Oregon.”
[ Washington. |

Range. — “cf.” Early Miocene (Vaqueros). Middle
Miocene (Temblor) to Recent. Recent from Forrester
Island, Alaska, to Scammon’s Lagoon, Lower California,
Mexico, between tides, burrowing to a depth of four
feet or more in unshifting sandy mud beaches in bays,
estuaries and sheltered areas. Burch reported dredging
empty shells at a depth of 46 meters (25 fathoms) off
Redondo Beach, California (Min. Conch. Club South.
Calif., No. 44, p. 30, February, 1945.)

Occurrence in San Diego Fm. — C.A.S. Loc. 1400,
1402, 1418, 28885, 28889. L.A.M. Loc. 107, 305, 305A,
319. S.D. Loc. 4, 27, 29 [=Loc. 1402 (CAS)]; Loe.
34, Cat. nos. 6386, 6387, 6389, Pacific Beach (casts).

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

U.C.L.A. Loc. 2359.

Original description: Test magna, ponderosa, calcar-
ea, sub-quadrilateralis, concentrice unduloso-plicosa, epi-
dermide flavido, rugoso induta, antice rotundata, postice
truncata et valde hians; umbonibus submedianis, acutis,
elevatis, undulatis: cardo gracilis, dente elevato oblique
triangulari instructus: cavitas ad apicem profunda; cica-
trice musculari lato, bene impresso; sinu siphonali minime
profundo. Long. 6; alt. 4; lat 3 poll. (Gould.)

Remarks: A number of specimens from the San
Diego Formation, in various states of preservation, agree
in all observable characters with Recent Panope generosa.
The largest specimen (incomplete), from Loc. 305 (LAM)
is 135 mm long. Another from the same locality is 98 mm
long, 63 mm high, convexity (both valves together) 41.6
mm. A specimen from Loc. 305A (LAM) is 114 mm long
and 75 mm high. Many fragments from these two local-
ities are present in the collections of the Los Angeles
County Museum. The largest specimen from the San
Diego Formation in the collections of the California
Academy of Sciences is 102 mm long (incomplete). The
largest Recent specimen in the Academy’s collection is
one collected in Puget Sound by Henry Hemphill, which
is 186.9 mm long, 101.5 mm high, convexity (both
valves together) 73.2 mm. Fitch (1953) mentioned that
huge Recent specimens of this mollusk (including the
animal) may weigh eight pounds.

There is variation in the shape of the fossils in the
present collections. The valves of some specimens are
more convex than others and on some the posterior dorsal
margin is nearly straight, on others concave. Similar varia-
tions can be observed in a series of Recent specimens and
are no doubt the result of the burrowing habit of this
mollusk.

Panope generosa solida Dall (1272) was described
with the locality cited as San Francisco, California.
According to Dall, this differs from the typical form in
that the ligamentary attachment is twice as long and the
pallial sinus is deeper. Experienced collectors have not
since found P. generosa nor any variety of it in that area
and according to Packard (1273) no specimens were
taken by the Albatross in their dredgings in and near
San Francisco Bay. The illustration of this form given by
Oldroyd (1274) is that of a broad, subquadrate shell and
it was said to occur with the typical form throughout
most of its range but Keen (1275) pointed out that
there are questions concerning the specimen illustrated as
type by Oldroyd.

Panope globosa Dall (1276) described from the
north end of the Gulf of California was said to be charac-
terized by the shell ‘‘of a yellowish white color, shorter,
thinner, and more globose than P. generosa and probably
distinct.”

We have examined two valves of this form collected
by E.P. Chace on the beach about 20-25 miles south of
San Felipe, Lower California. These are more globose and
the posterior end is narrower than comparable specimens
of P. generosa, and apparently represent a distinct species.
The right valve is 151 mm long, 106 mm high, the con-
vexity (one valve) 38 mm.

Records of P. generosa from beds of Pliocene age in
the Gulf of California region are probably referable to
P. globosa.

Several named forms from the Cenozoic of western

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

North America are either identical with or very closely
allied to the Recent species. The form from the middle
Miocene at Astoria, Oregon, named Mya abrupta (1277)
by Conrad may be identical with Panope generosa. Moore
(1278) examined the type specimen of Conrad’s species
and considered Panope generosa to be identical and
placed the latter in the synonymy of P. abrupta. She
described the type specimen of P. abrupta as a thin-
shelled form 65.8 mm long and 39.2 mm high. This is
smaller than most adult shells of P. generosa. The west
American species of Panope are in need of monographic
study. For the present we use the name Panope generosa
for Recent and for the Pliocene specimens mentioned in
the present report.

There have been differences of opinion by authors
concerning the Miocene species named Glycimeris estrell-
anus (1279) by Conrad. The original figure is that of an
imperfectly preserved specimen, and there is doubt con-
cerning its specific characters. Moore (1963, p. 83-84)
placed it in the synonymy of P. abrupta. Clark (1280)
discussed what he considered to be the differences be-
tween this fossil and the Recent Panope generosa. Later
the same author proposed the name Panope ramonensis
(1281) for a fossil from near Walnut Creek, California, in
beds which he referred to late Oligocene age. In the syn-
onymy of this species he cited the ‘‘Panope cf. estrellana
Conrad” of his earlier work.

Panope tenuis Wiedey from Temblor strata of
middle Miocene age and P. taeniata Dall described from
beds of Pleistocene age at Magdalena Bay, Lower Califor-
nia, are both much narrower posteriorly than the Recent
species described by Gould. The type specimen of Panope
similaris Dall and Ochsner from Pliocene strata in the
Galapagos Islands also is more attenuated than typical
P. generosa.

The species occurring in Japan from Miocene to
Recent, cited by some authors under the name of Panope
generosa, is now referred to Panope japonica A. Adams
(1282)

GENUS PANOMYA GRAY

Panomya M. E. Gray, Fog. Moll. Anim., Vol. 5, p. 29, pl.
346, fig. 1, 1857. Sole species, ‘‘P. norvegica, t. 346, f.
1.” — Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4,
p. 832. 1898. ““Type Panopea (Mya) norvegica Speng-
ler.”—Lamy, Jour. de Conchyl., Vol. 68, No. 4, p. 261,
1925. Type, Mya norvegica Spengler. = Panopaea
spengleri Valenciennes. — Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 425, 1931. Type (by
monotypy), Mya norvegica Spengler.

Type species (by monotypy). — Panomya_ nor-
vegica Spengler [ = Mya norvegica Spengler, Acta Soc.
Hist. Nat. Hafn., Vol. 3, p. 46, pl. 2, fig. 18, 1793. (Not
Mya norvegica Gmelin, 1790, which is a Lyonsia.) Illus-
trated by M. E. Gray, 1857, pl. 346, fig. 1—Gould, Rept.
Invert. Massachusetts (Boston), (edited by W. G. Binney),
p. 52, fig. 373, 1870 (as Panopaea arctica Lamarck). —
Sowerby, Reeve’s Conch. Icon., Vol. 19, Panopaea, sp. 7,
pl. 5, fig. 7, 1873 (as Panopaea spengleri Valenciennes.)
— Davies, Tertiary Faunas (T. Murby & Co.: London), p.
201, fig. 269 (p. 196), 1935. — N. Macginitie, Proc. U. S.

329

Nat. Mus., Vol. 109, No. 3412, p. 189, pl. 19, fig. 1; pl.
25, figs. 6, 8, 1959 ( as Panomya arctica) }.

Range.—Late Oligocene or early Miocene to Recent.
Recent, from the intertidal zone, occasionally 46 to 600
meters (25 to 328 fathoms).

Description. — Shell differs from Panope in that it is
shorter in proportion to the height, in the presence of a
pronounced medial radial depression and in that the
pallial line is broken into an irregular series of rounded
impressions.

Remarks.—This genus has been reported from Japan
from late Oligocene or early Miocene to Recent: from the
northeastern Pacific from late Miocene or Pliocene to Re-
cent and in the Arctic region and in northern Europe
from Pliocene to Recent. It is essentially an inhabitant of
intertidal or shallow boreal and Arctic waters. However,
the type species, Panomya arctica in the Atlantic, has
been reported (1283) from depths of 530-600 meters
(290-328 fathoms).

At the present time Panomya has not been reported
living south of Puget Sound along western north Amer-
ica, but during Pliocene time it occurred as far south as
San Diego, California. The fossil and Recent species of
Panomya from Japan have been discussed by Kanno
(1284).

A large specimen of Panomya gigantea Kanno from
strata of Pliocene age in Japan, is 137 mm long and 98
mm high.

Panomya cf. P. beringiana Dall
Plate 56, Figures 12

The following references, type locality and range
refer to typical P. beringiana.

Panomya beringiana Dall, Proce. U. S. Nat. Mus., Vol. 52,
No. 2183, p. 416, December 27, 1916. — I. S. Old-
royd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol.
1, p. 207, 1924. Type locality cited. Range: eastern
Bering Sea. — Woodring, Bramlette, and Kew, U.S. G.
S., Prof. Paper 207, p. 85, pl. 33, figs. 13, 14, 1946.
Timms Point Silt, San Pedro, Pleistocene.

Type specimen. — No. 212875, United States Nat-
ional Museum.

Type locality. — “Station 3529, near the Pribiloff
Islands, in 56 fathoms.”

Range. — Late Pliocene to Recent. Recent from the
Aleutian Islands to Puget Sound in 102 to 146 meters
(56 to 80 fathoms). Probably also in Japan.

Occurrence in San Diego Fm. — C.A.S. Loc. 1418.
L.A.M. Loc. 305.

Original description. — Shell resembling P. arctica
Lamarck, in a general way, but thinner, less cylindrical,
much larger, and proportionately shorter. Length, 130;
height, 80; diameter, 50 mm. (Dall, 1916.)

Remarks.—Two specimens from the San Diego For-
mation in the collections of the California Academy of
Sciences are referable to the genus Panomya. The speci-
mens are incomplete casts which retain only portions of
the shell. The larger of these is 52.5 mm long and 46 mm
high. A very well developed radial median depression is
present on these fossils. A fragment of a thin shell 30 mm
long, from Loc. 305 (LAM), appears to be referable to the

330

same species.

Several species of Panomya have been recorded
from boreal west American waters. The earliest valid
name appears to be Glycimeris arctica Lamarck (1285).
Mya norvegica Spengler, 1793, is a synonym of Lam-
arck’s species because of an earlier Mya norvegica Gmelin,
1790, which is referable to the genus Lyonsia.

Dall in 1898 described Panomya ampla (1286) in
the synonymy of which he placed ‘‘Panopaea norwegica
Spengler” illustrated by Middendorff (1287). Dall char-
acterized this species as follows: “This differs from P. nor-
vegica by its much more heavy and rude shell, with a
more expanded posterior region, and flatter, more irregu-
lar valves.” His illustration is that of a decidedly trigonal
valve, the dorsal margin nearly straight and the anterior
end very narrow in comparison to the broad posterior
end. MacNeil (1288) in 1943 cited P. ampla from beds of
Pliocene and perhaps Pleistocene age from near Nome,
Alaska. His illustration shows a right valve which anterior-
ly tapers to a blunt point. Oldroyd (1289) illustrated a
shell under the name of Panomya ampla from Puget
Sound the shape of which is more that of P. beringiana
but according to MacGinitie (1959, p. 189) this illustra-
tion represents ‘P. turgida (=P. arctica).”’ Grant and Gale
(1290) also illustrated a shell from the same region which,
according to Woodring (1946, p. 85) resembles P. ber-
ingiana, The illustration by Kira (1291) of a species
from Japan under the name of P. ampla likewise appears
to be referable to P. beringiana. The illustrations of Grant
and Gale and that of Kira were all referred to P. arctica by
MacGinitie, who, however, did not refer to P. beringiana.

The next species in chronological order of date of
description is Panomya (ampla var.?) chrysis Dall (1292),
a fossil from the Empire beds of Pliocene age at Coos
Bay, Oregon. Dall considered this to differ from P. ampla
“from which the valves differ in being thin, instead of
enormously thickened, and in wanting the conspicuous an-
terior oblique truncation of the living species.”” Howe
(1294) placed this in the synonmy of P. ampla and this
arrangement was followed by Grant and Gale. We have
examined a cast of the type specimen of the fossil from
Coos Bay, Oregon, and can add nothing to Dall’s observa-
tions on that form.

In 1916 Dall described two forms from Alaska, Pan-
omya beringiana and Panomya arctica var. turgida. Pan-
omya beringiana was described as differing from P. arctica
in the thinner shell, less cylindrical form, and in the larger
size and proportionally shorter shell. The illustration of
species by Woodring, Bramlette, and Kew, shows a shell
which is anteriorly attenuated and rounded at the end
and the anterior dorsal margin slopes downward and does
not form an almost straight line with the posterior dor-
sal margin as does that of P. ampla.

Panomya arctica turgida Dall (1294) was described
as ‘“‘shell very similar to the North Atlantic form but very
much more capacious and larger. Length, 90; height, 60;
diameter, 48 mm. Cat. No. 151334, U. S. N. M.” Clark
(1294) illustrated a fossil from the Yakataga Formation in
southeast Alaska of late Miocene or early Pliocene age.
This form appears to be much more elongate, more cy-
lindrical, and to have a thicker shell than do the fossils
from the San Diego Formation. According to Woodring,
P. turgida is more inflated and has a less conspicuous me-
dian groove than the late Pliocene or Pleistocene fossils

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

from the Los Angeles district which he referred to P.
beringiana.

There has been confusion in the literature concern-
ing the three forms described by Dall. Woodring (1946, p.
85) stated that records of P. ampla and P. turgida from
beds of Pliocene and Pleistocene age in southern Calif-
ornia are referable to P. beringiana. Eyerdam (1296)
pointed out that a species in his collection from Victoria,
British Columbia, formerly believed to be P. ampla, was
later identified by A. M. Keen as Panomya turgida. Sch-
lesch (1297) considered P. turgida to be a virtual
synonym of P. norvegica.

From the foregoing it appears that the several
named forms of Panomya in the northeastern Pacific are
quite similar and that too many names have been pro-
posed for them. A species from Japan compared with P.
ampla was described as Panomya nipponica by Nomura
and Hatai (1298). Habe (1299) recorded P. ampla from
Japan and stated ‘‘as the writer observed all kinds of
transitional forms among P. ampla, P. turgida and P.
nipponica in many species from Nemoro and Akkeshi,
those three species seem to be merely the local or indivi-
dual forms of one species.” Kanno (1957, p. 13) con-
curred in this opinion.

The imperfect preservation of the fossils from San
Diego makes identification of the species doubtful. The
median depression on these fossils is more pronounced
than it is on Dall’s type specimen of P. ampla chrysis Dall
from the Empire beds at Coos Bay, Oregon.

We compare the present fossils to P. beringiana,
whose shell characters are well known, because of the gen-
eral similarity, the pronounced median groove and thin
shell. Furthermore, what is probably this species has been
recorded occurring in the Careaga Sandstone of Pliocene
age in the Santa Maria district (1300) and Faustman
(1301) has recorded it from strata of middle Pliocene age
in Humboldt Co., California. We have observed a lot of
16 specimens of P. beringiana from near the latter loc-
ality which were collected by Bruce Martin at Loc. 119
(CAS).

SUPERFAMILY PHOLADACEA
RAFINESQUE (1302)
FAMILY PHOLADIDAE RAFINESQUE
(1303)

Shells with a narrow, slit-like to nearly circular pe-
dal gape, which may or may not be closed by a callum in
the adult stage. Anterior portion of the valves imbricate
and often ribbed. This portion is often separated from the
posterior portion by an umbonal-ventral sulcus. Hinge
teeth usually lacking, a small chondrophore present in
some forms, ligament if present, internal. Anterior dor-
sal margin of the valves reflected, forming the attachment
area for the externally placed anterior adductor muscle.
In the adult stage of most forms the chitinous cover
(cephalic hood) of the anterior adductor muscle is coy-
ered by accessory plates or by a dorsal extension of the
callum. The total number of accessory plates in any one
species may vary from one in Barnea and Zirfaea to four
in Martesia and Parapholas. Apophyses are present in the
Pholadinae and Martesiinae, but absent in the Jouanne-
tiinae and Xylophagainae. Pallial sinus usually deeply in-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

set. (Adapted from Turner.) Jurassic to Recent.

Remarks. — The members of this group of mollusks
occur world wide and live from the intertidal zone to a
depth of 457 meters (250 fathoms). They burrow into
rock, wood, or other shells. The greatest number of
genera occur in warm temperate, subtropical and tropical
waters. Turner pointed out that the greatest development
of this group is in the eastern Pacific where there are 13
genera and 23 species in comparison to 8 genera and 13
species in the western Atlantic.

An excellent work by Turner (1304) deals with the
Pholadidae of the western Atlantic and of the eastern Pac-
ific. Lamy (1305) discussed the species in the collections
of the Natural History Museum in Paris.

Key to Genera of Pholadidae

A. Callum present; shell gaping
along posterior half of dorsal

and ventral margins . Penitella
B. Callum lacking; shell gaping
only at both ends . Zirfaea

GENUS ZIRFAEA GRAY

Zirfaea Gray, Synop. Brit. Mus., ed. 42, p. 150, 1840.
[No description nor species. ] — Gray, Synop. Contents
Brit. Mus., ed. 44, p. 76, 1842. [Brief description, no
species cited.] [Concerning the preceding references,
see Iredale, Proc. Malacol. Soc. London, Vol. 10, Pt.
IV, pp. 298, 303, 309, March, 1913.] — Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 432,
1931. “Type (by subsequent designation, Gray, 1847),
Pholas crispatus Linnaeus.’’ — Turner, Johnsonia, Vol.
3, No. 33, p. 54, 1954. ‘“‘Genotype, Pholas crispata
Linné, subsequent designation, Gray, 1847.”

Thurlosia Catlow and Reeve, The Conchologist’s Nomen-
clator, p. 3, 1845. “Thurlosia crispata, Leach” cited in
synonymy of “P. crispata, Linn., Syst. Nat. p. 111;
Enc. meth. pl. 169, f. 5-7.”

Zirphaea Leach, Synop. Moll. Great Britain, pp. 250, 252,
1852. Zirphaea crispata Linnaeus and synonymy cited.

Type species (by subsequent designation, Gray,
Proc. Zool. Soc. London for 1847, p. 188, 1847).—‘‘Ph.
crispata”’ { = Mya crispata Linnaeus, Syst. Nat.,ed. 10, p.
670, 1758. Ref. to “List. angl. t. 5. f. 38” and “app. t. 2.
f. 7.” “Habitat in O. septentrionali.” Also illustrated by
Sowerby in Reeve’s Conch. Icon., Vol. 18, Pholas, pl. 3,
fig. 9, 1872. “Hab. Great Britain.” — Turner, 1954, p. 55,
pls. 1, 3, 28, 29, and pl. 30, figs. 1-3].

Range. — Middle Miocene (Temblor) to Recent. Re-
cent in boreal and warm temperate waters of the Atlantic
and Pacific oceans of the northern hemisphere; boring in
consolidated mud or clay, rock, occasionally wood, from
the intertidal zone to 128 meters (70 fathoms).

Description. — Shell oval in outline, beaked ant-
eriorly, rounded to truncate posteriorly, widely gaping at
both ends and having a sulcus extending from the umbo
to the ventral margin. There is a single dorsal accessory

331

plate, the mesoplax, which is small and more or less tri-
angular in outline. Apophyses solid, strongly curved,
broadened and often spoon-shaped at the free end. (Tur-
ner, 1954.)

Remarks. — Two species of Zirfaea have been re-
ported from beds of late Tertiary age in California, one of
which now lives in west American waters. Zirfaea is here
reported from the San Diego Formation for the first time.

Zirfaea cf. Z. pilsbryi Lowe

The following references, type locality, range and
description refer to typical Z. pilsbryi.

Zirfaea gabbi Tryon, I. S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 210, pl. 36, fig. 1,
1924. “Bering Sea and islands south to San Diego.”
[Not the locality “Japan.’] Also Pleistocene.

Not Zirphaea gabbii Tryon, Proc. Acad. Nat. Sci. Phil-
adelphia, Vol. 15, p. 144, pl. 1, fig. 1, 1863. “‘Hab.
Coast of Japan?”

Zirfaea pilsbryi Lowe, Nautilus, Vol. 45, No. 2, p. 53, pl.
3, figs. 1, 2, October, 1931. “‘Bolinas, California.” —
Morris, Field Guide to Shells of the Pacific Coast and
Hawaii (Houghton Mifflin Co.: Boston, Massachusetts),
p. 63, pl. 18, fig. 7, 1952. “Bering Sea to Lower Cal-
ifornia.”” — Fitch, State Calif. Dept. Fish Game, Mar.
Fish. Branch, Fish Bull. No. 90, p. 95 fig. 61, 1953.
““Nunivak Island, Alaska, to San Juanico Bay, Baja Cal-
ifornia.”” — Turmer, Johnsonia, Vol. 3, No. 33, p. 58,
pl. 30, figs. 4-9; pls. 31-34, 1954. Various localities
cited. Range same as cited by Fitch.

Type specimen. — No. 50809, Academy of Natural
Sciences of Philadelphia.

Type locality. — ‘‘from Bolinas, California.”

Range. — ? Late Miocene; Pliocene to Recent. Re-
cent from Nunivak Island, Alaska, to San Juanico Bay,
Lower California, Mexico, from the intertidal zone to 24
meters (13 fathoms); boring in mud and in clay banks to a
depth of 25 to 30 cm., occasionally in water-logged wood.

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Original description of Z. pilsbryi. — Shell large,
transverse, obliquely divided by a shallow furrow pro-
ceeding from the umbonal apex to the basal margin and
forming a corresponding rib on the internal surface of
valve. Posterior to the furrow the shell is marked only by
growth wrinkles; on the anterior half they appear as sharp
ribs which are produced into sharp spines in unevenly
spaced radiating lines continuing to the sharply crenu-
lated margin. Diameter of type, 36 mm.; alt., 37 mm.;
length 75.5 mm. (Lowe.)

Remarks. — The present record of Zirfaea cf. Z. pils-
bryi from the San Diego Formation is based upon frag-
ments, the largest about 15 mm long. These retain the
widely spaced concentric sculpture surmounted by fine
spines such as occur on the anterior dorsal portion of
valves of Recent Z. pilsbryi.

The shell of Recent Z. pilsbryi is longer and narrow-
er and the internal apophyses broader and more concave
than those of the shell of Z. crispata Linnaeus, a
European species.

Turner (1954) gave a thorough description of Z. pils-
bryi and MacGinitie (1306) discussed its ecology and

332

boring habits. More recently Yonge (1307) also remarked
on the boring habits of this species.

A subspecies, “‘Zirfaea gabbi Tryon femii” Adegoke
(1308), was described from the San Joaquin Formation of
late Pliocene age in the Coalinga district. It is said to
differ from the typical subspecies in the more elongated
outline, more widely spaced concentric lamellae on the
anterior end and in other features.

GENUS PENITELLA VALENCIENNES

Penitella Valenciennes, in Abel du Petit-Thouars, Voyage
autour du monde sur la Frégate La Venus, Atlas de
Zoologie, Mollusques, pl. 24, 1846. [No text.] Species
cited: ‘“‘Penitella conradi. (Nob.),” “‘Penitella xilophaga.
(Nob), ‘‘Penitella tubigera. (Nob.),” — Turner, John-
sonia, Vol. 3, No. 34, p. 70, March 29, 1955. “Geno-
type, Penitella conradi Valenciennes, subsequent de-
signation Habe 1952.”

Type species (subsequent designation by Habe, Gen.
Jap. Shells, Peleeypoda, No. 3, p. 243, May, 1952).—
“Type species: Penitella conradi Valenciennes.”

Range. — Late Oligocene (San Ramon) to Recent in
the north and northeast Pacific. Recent from intertidal
zone to a depth of 79 meters (43 fathoms).

Description. — Shells small to moderate in size, the
larger species reaching about 95 mm (about 3 3/4 inches)
in length, oval in outline, divided into two distinct regions
by an umbonal-ventral sulcus and producing a callum in
the adult stage. Shell beaked and widely gaping anteriorly
in the young stage, with a nearly circular pedal gape.
Valves rounded to truncate and closed posteriorly, the
siphon being capable of complete retraction within the
shell. Umbonal reflections variable, ranging from those
which are thin and very closely appressed so that the
sculpture of the shell shows through, to those which are
heavy and free anterior to the umbos. Protoplax lacking,
being replaced by the dorsal extension of the callum.
Mesoplax transverse, in one piece and, in young speci-
mens, very similar to that found in Zirfaea. In the adult,
a dorsal portion is added to the mesoplax which grows
forward and encloses the posterior portion of the ant-
erior adductor muscle. Metaplax and hypoplax lacking,
siphonoplax variable, present or absent. Siphonal tube
lacking. (Turner.)

Remarks.—The shell of Penitella differs from that of
Pholadidea Turton (1309) in that the mesoplax is in one
piece rather than divided longitudinally into two more or
less triangular pieces, the two portions of the siphonoplax
are not fused and are often diverging, the apophyses are
thick, expanded and often blade-like at the free end,
whereas those of Pholadidea are small, narrow and fragile.

Five species of Penitella live in the eastern Pacific
in the region between Bering Island, Siberia, and Bahia
Tortola (Turtle Bay), Lower California, and an equal
number of species has been reported from the late Ter-
tiary in the same region. Two of these are present in the
collections from the San Diego Formation. Two Recent
species and one fossil form have been reported recently
from Japan (see Adegoke, Proc. Calif. Acad. Sci., Ser. 4,
Vol. 35, No. 1, p. 18, 1967.)

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

Key to Species of Penitella

A. Shell short and globose; mesoplax
pointed anteriorly, truncated posteriorly;

maximum length about 33 mm . conradi
B. Shell elongately ovate; mesoplax

pointed posteriorly, truncated anteriorly;

maximum length about 93 mm . penita

Penitella conradi Valenciennes
Plate 57, Figures 5, 13

Penitella conradi Valenciennes, in Abel du Petit-Thouars,
Voy. autour du Monde sur la Fregate La Vénus, Atlas
de Zool. Moll., pl. 24, fig. 1, 1846. [No decription
nor locality.|—Lamy, Bull. Mus. Nat. Hist. Nat., Paris,
Vol. 27, No. 2, p. 179, 1921. Monterey, California. —
Lamy, Jour. de Conchyl., Vol. 69, No. 3, p. 152, 1926.
Earlier records cited. — Turner, Johnsonia, Vol. 3, No.
34, p. 75, pls. 43-46, 72, figs. 1, 2, March 29, 1955.
Range, “From Gualala, Mendocino County, California
south at least as far as Bahia San Bartolomé, Baja Cal-
ifornia.”

N[avea]. subglobosa Gray, Ann. Mag. Nat. Hist., Ser. 2,
Vol. 8, No. 47, p. 385, November, 1851. “Hab. Cali-
fornia, in a hole in a shell.”

N[avea]. Newcombii Tryon, Amer. Jour. Conch., Vol. 1,
Pt. 1, p. 39, pl. 2, figs. 1-3, February 25, 1865. “‘Hab-
itat Australia.” In Vol. 1, Pt. 3, p. 285, July 1, 1865, it
is stated ‘““Dr. Newcomb informs us that the locality of
Navea Newcombii, stated in our description of that
species, (p. 39) is erroneous. The specimens were ex-
tracted from a Haliotis from Lower California.”

Penitella parva Tryon, Amer. Jour. Conch., Vol. 1, Pt. 1,
p. 39, pl. 2, figs. 4, 5, February 25, 1865. “Habitat,
Lower California, in Haliotis.””

Type specimen. — Muséum Nationale d’Histoire
Naturelle de Paris.

Type locality. — Monterey, California (from label
with type specimen) (Lamy).

Range. — Middle Pliocene to Recent. Recent from
Vancouver Island, British Columbia, to Bahia Tortolo
(Turtle Bay), Lower California, and possibly further,
often boring in shell of Haliotis, or in clay or soft rock,
from intertidal zone to 18 meters (10 fathoms).

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Description. — No original description. Diagnostic
characters given by Turner, 1954, are: Shell usually found
boring into Haliotis or other shells; occasional specimens
are found in clay and soft stone. Umbonal reflections
broad and closely appressed for their entire length. Meso-
plax truncate posteriorly, pointed anteriorly and lacking
lateral wings. Siphonoplax heavy, not diverging and com-
posed of a chitinous outer layer which is lined with a
white, granular, calcareous deposit.

Remarks. — Two small, oval, nearly smooth valves
of Penitella conradi in the present collections were in a
hole bored in a fragment of a shell (possibly a pectenoid).
Dr. Ruth Turner kindly verified the identification of the
species. A large specimen from Loc. 305C, the mesoplax

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

lacking, the interior filled with soft sandy silt, is 25 mm
long, 20.3 mm high, convexity (both valves together),
19.2 mm. The shell characters of this specimen agree well
with those shown in Turner’s illustrations of P. conradi as
well as with those of Recent specimens identified as that
species in the collections of the California Academy of
Sciences.

Specimens of Penitella conradi are similar to those
of juvenile P. penita but can be separated from the latter
by the shorter, more rounded posterior slope and by the
shorter, more sharply upturned concentric ridges on the
anterior portion of the shell.

Tumer (1955) gave a thorough discussion and good
illustrations of P. conradi. Large Recent specimens were
reported by her to be 33 mm long and 16.5 mm high. She
included Martesia intercalata Carpenter (1310) from Maz-
atlan, Mexico, in the synonymy but that locality was not
included in the range given for P. conradi.

Smith (1311) recently discussed the morphology of
P. conradi relative to its ability to penetrate shell material.

Penitella penita Conrad
Plate 56, Figures 8, 9, 16; Plate 57, Figures 1, 2

Pfholas]. penita Conrad, Jour. Acad. Nat. Sci. Philadel-
phias Voly 7, Pt. 25 ip. 2375 ple 18; fig. 7, 1837.

Pholas concamerata Deshayes, Rev. Zool., Soc. Cuvieér-
ienne, [Vol. 2] p. 357, Ann. 1839. ‘Californie, dans
les marnes calcaires des rivages.’’ — Deshayes, Mag. de
Zool., Guérin-Meneville, Ser. 2, Vol. 2, pl. 17, 1840.

Penitella spelaeum Conrad, House Doc. 129, Projected
Vol. 3, 33rd Congress, 1st Session, 1855. App. to Pre-
lim. Geol. Rept. of W. P. Blake, p. 16. ‘““Locality.—San
Pedro. Recent formation.’”” — Conrad, U. S. Pacific
Railroad Expl., Vol. 5, Pt. 2, Art. 2, pp. 319, 326, pl.
5, figs. 43, 43a, 43b, 1857 (as P. spelaea). Locality
same as in preceding reference.

Penitella curvata Tryon, Amer. Jour. Conch., Vol. 1, Pt. 1,
p. 40, pl. 2, figs. 6, 7, 8, February 25, 1865. “Habitat,
Straits of Fuca.”

Pholadidea sagitta (Stearns MS.), Dall, Proc. U. S. Nat.
Mus., Vol. 52, No. 2183, p. 417, December 27, 1916.
“The type-specimen comes from Monterey, California.”
[A young specimen according to Turner, 1954.]

Pholadidea penita Conrad, I. S. Oldroyd, Stanford Univ.
Publ. Ser. Geol. Sci., Vol. 1, p. 211, pl.21, fig. 10
(copy of Conrad’s original figure); pl. 51, figs. 3a, 3b,
1924. “Range. Chirikoff Islands, Alaska, to San Pedro,
California.”

Penitella penita Conrad, Fitch, State Calif. Dept. Fish
Game, Mar. Fish. Branch, Fish Bull. No. 90, p. 97, fig.
63, 1953. ‘“‘Range: Chirikoff Island, Alaska, to Turtle
Bay, Baja California.”—Turner, Johnsonia, Vol. 3, No.
34, p. 80, pls. 5 (fig. No. 33), 47-51, 1955. Bering
Island, Siberia, to Bahia Bartolomé (Turtle Bay), Low-
er Califomia. — Evans, Proc. Malacol. Soc. London,
Vol. 38, Pt. 2, pp. 111-119, pls. 1-4, figs. 1-6 in text,
August, 1968. Oregon, Recent.

Type specimen. — Location unknown to the present
authors.
Type locality. — “‘Inhabits with the preceding’.

[That is, P. californica and Cypricardia californica which

333

“TInhabits soft argillaceous rocks, which are bare at low
water, with the Pholades, in the vicinity of Sta. Diego and
Sta. Barbara.’’]

Range. — Middle Miocene (Topanga Formation) to
Recent. Recent from Bering Island, Siberia, to Point Abre-
ojos (1312), Lower California, Mexico, in intertidal zone,
in cavities excavated in clay, hard rock, or cement. Dredged
at the depth of 79 meters (43 fathoms).

Occurrence in San Diego Fm. — S.D. Loc. 417.
Loc. 312 [ = 417 (SD)].

Original description. — Shell ovate, elongated, con-
tacted submedially and grooved; anterior side inflated,
with decussating lines, the radiating striae having a granu-
lated appearance, posterior side subcuneiform, extremity
truncated, with a membranous expansion or appendage;
apophysis oblique, slender, spoon shaped at the extremity.
(Conrad.)

Remarks. — One right and three left valves are pre-
sent in the collections from San Diego studied by us. These
are single valves, imperfectly preserved, the largest is 52
mm long, 28.6 mm high, convexity, 14 mm. Large Recent
specimens attain a length of 92 mm.

The accessory plates are lacking on the fossils in the
present collections and identification of the species is
based upon other shell characters. The shape of the meso-
plax, when present, pointed posteriorly, easily serves to
separate this species from similar ones. The broad, closely
appressed umbonal reflection on the present specimens is
characteristic of Penitella penita in comparison to the
narrower, higher reflection present on P. gabbi Tryon and
Chaceia ovoidea Gould. The shell of P. penita attains a
much greater size than that of P. conradi Valenciennes
which rarely exceeds 33 mm in length. The mesoplax of
P. conradi is truncated posteriorly rather than pointed.
The callum of adult specimens of P. penita is complete,
that of P. fitchi is not complete but has a pedal gape, that
of P. gabbi does not cover the extreme anterior end of the
valves. All these west American species have been dis-
cussed and illustrated by Turner. The shape of the shell of
P. penita is variable and may be a result of crowding or to
the hardness of the substrate (Evans, 1968).

Penitella penita has not been recorded with certainty
as occurring earlier than in beds of middle Miocene (1313)
age. A fossil was cited as ‘‘Pholadidea aff. penita Conrad”
by Clark (1314) from beds of Oligocene age southwest of
Walnut Creek, California, but the state of preservation
precluded positive identification. The same author later
described a species from the same area under the name of
Pholadidea (Penitella) lorenzana (1315). This fossil form
was described as differing from P. penita in the much
greater size, wider mesoplax which is pointed at the an-
terior end and the upper surface flat rather than concave.

Penitella turnerae Evans and Fisher (1316) deseribed
from Coos Bay, Oregon, differs from P. penita by its lack
of a siphonoplax and by its larger size. Furthermore, the
mesoplax, posteriorly, is narrowly crescentic whereas that
of P. penita is sharply pointed and that of P. gabbi is
acutely rounded.

A species in Japan, formerly referred to P. penita,
was renamed P. chishimana by Habe (1317). The oriental
species is said to differ from the California form in that
the posterior end is not truncated and the growth lines are
undulated. Records of Recent and perhaps fossil (1318)
forms from Japan and possibly some from the north Pa-

334

cific cited under the name of P. penita may be referable to
P. chishimana or other species.

FAMILY TEREDINIDAE RAFINESQUE
(1319)

Much has been written concerning members of the
family Teredinidae because of damage resulting from their
habit of boring wood thus wreaking destruction upon
wooden ships, pilings, or other structures.

A recent illustrated catalogue of the Teredinidae by
Turner (1320) is indispensible to anyone working with
this group of organisms.

[ ‘‘Xylotrya” sp.]

“Xylotrya, sp. indet. Tube only.”’, Dall, Proc. Calif. Acad.
Sci., Vol. 5, p. 296, 1874. ‘“‘well at San Diego,’’ Plio-
cene. — Orcutt, West Amer. Sci., Vol. 6, Whole No.
46, p. 85, 1889. Dall’s record (1874) cited. — Or-
cutt, quoted by Ellis in Ellis and Lee, U. S. G. S., Water
Supply Paper 446, p. 59, 1919. Dall’s record (1874)
cited. — Hertlein and Grant, Mem. San Diego Soc. Nat.
Hist., Vol. 2, p. 48, 1944. Dall’s record (1874) cited.

Specimen. — Probably lost in the earthquake and
fire of 1906.

Occurrence in the San Diego Formation.—San Diego
well (Dall).

Remarks. — The sole record, repeated by later au-
thors, of “Xlotrya, sp.” from the San Diego well, is that
of Dall in 1874. No further information is available con-
cerning the tube upon which this record was_ based.

Xylotrya Leach of authors (non Leach in Menke,
1830), was referred to the genus Bankia Gray by Clench
and Turner (1946, p. 8). The type species of Bankia is
Teredo bipalmulata Lamarck.

A paper by Clench and Turner (1321) contains an
excellent discussion accompanied by many pertinent re-
ferences dealing with the members of the genus Bankia in
the western Atlantic.

Xylotrya Leach in Menke, 1830, was placed by
Turner 1955, in the synonymy of Xylophaga Turton, fam-
ily Pholadidae subfamily Xylophaginae.

Under the current rules of the International Comm-
ission on Zoological Nomenclature Xylophaga Turton
1822 (1322), type, X. dorsalis Turton, is not preoccupied
by Xylophagus Meuschen, 1788, and the name Xylo-
tomea Dall, 1898 (1323) suggested as a possible sub-
stitue, is not needed because Meuschen’s work has_ been
rejected for nomenclatural purposes by the Internat.
Comm. Zool. Nomencl., Opinion 260.

It seems possible that the fossil tube from the San
Diego well may be referable to one of the genera of Ter-
edinidae now occurring in west American waters. Any
further remarks concerning it at the present time would be
sheer speculation.

SUBCLASS ANOMALODESMATA DALL (1324)
ORDER EUDESMONTIDA COX (1325)

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

SUPERFAMILY PANDORACEA RAFINESQUE (1326)

Shell usually of medium size, thin, with a nacreous
inner layer (except Thraciidae), with or without a perios-
tracum; right valve flat, the left convex; hinge with chon-
drophore and buttresses, sometimes with a lithodesma;
pallial sinus lacking in some families, present in others.
Late Triassic to Recent.

FAMILY PANDORIDAE RAFINESQUE (1327)

Shell compressed, inequivalve, free, solid, with nac-
reous and prismatic layers; the dorsal edges of the valves
overlapping but not socketed, with dentiform crural ridges
on either side of the resilium, but no true teeth; ligament
amphidetic, external, obsolete; resilium internal, opistho-
detic, usually reinforced on its anterior surface by a medial
elongate lithodesma; area none; valves closed, beaks en-
tire, pallial line simple. (Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 3, p. 532, 1895). Eocene to Recent.

A pallial sinus is lacking in this group. The pallial
line is marked by a fine line of small scars extending in
an are between the two adductor impressions.

GENUS PANDORA HWASS

Pandora Hwass in Chemnitz, Neues Syst. Conchyl. - Cab.,
Bd. 11, p. 211, 1795. Tellina inaequivalvis and T. cry-
stallina cited. — Bruguiere, Encycl. Method., Vers Tes-
taces, Vol. 2, pl. 250, figs. la-c, 1797. (Genus name
only.) — Lamarck, Mem. Soc. Hist. Nat. Paris, An VII,
p. 88, 1799. Sole species, Tellina inaequivalvis Linn-
aeus. — Boss and Merrill, Johnsonia, Vol. 4, No. 44, p.
189, 1965. ‘“‘type species my monotypy, Lamarck,
1799, Tellina inaequivalvis (Linnaeus).”

Calpodium Roding in Bolten, Mus. Bolt., p. 166, 1798.
For C. albidum Bolten, in synonymy of which was in-
cluded Tellina inaequivalvis with reference to Chem-
nitz, Conchyl. -Cab., Vol. 6, pl. 11, figs. 106, a, b, ¢,
d. [=Tellina inaequivalvis Gmelin.] — Winckworth,
Jour. Conch., Vol. 20, No. 2, p. 52, 1934.

Type species (designated by Children, Quart. Jour.
Sci., Vol. 14, p. 302, January, 1823). — ‘P. rostrata (Tell-
ina inequivalvis. Linn.)” [ = Solen inaequivalvis Linnaeus,
Syst. Nat., ed. 10, p. 673, 1758. ‘“‘Habitat in M. Med-
iterraneo.”’ Also illustrated by Hanley, Ipsa Linnaei Con-
chylia, pl. 1, fig. 6, 1855. — Sowerby, Reeve’s Conch.
Icon., Vol. 19, Pandora, sp. 2, pl. 1, figs. 2a, 2b, 1874.
“Hab. Great Britain.”” See Dodge, Bull. Amer. Mus. Nat.
Hist., Vol. 100, Art. 1, p. 46, 1952. — Allen, M. F., and
Allen, J. A., discussed the habits of this species (Proc.
Malacol. Soc. London, Vol. 31, Pts. 5 and 6, pp. 175-185,
figs. 1-5 in text, December 30, 1955.]

Range. — Eocene to Recent in Europe; late Oligo-
cene (San Ramon) or early Miocene to Recent in North
America. Recent from the littoral zone to 1902 meters
(1040 fathoms).

Description. — Shell inequivalve, thin, pearly inside;
valves close, attenuated, behind; right valve flat, with a

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

diverging ridge and cartilage-furrows; left valve convex,
with two diverging grooves at the hinge; usually no ossicle;
pallial line slightly sinuated. Outer layer of regular vertical,
prismatic cells. (Tryon, G. W., Jr., Structural and Syste-
matic Conchology, Vol. 3, p. 143, 1884.)

Remarks. — Three species of Pandora have been re-
corded occurring in strata of Pliocene age in California,
one of which occurs in the San Diego Formation.

Recent members of this genus are world wide in
distribution but they are most abundant in cold or cool
temperate waters. Eight species have been recorded as
occurring at the present time in marine waters between
the Bering Sea and San Diego, California. The extreme
range in depth cited for these species is 5 to 369 meters
(3 to 202 fathoms), but the average depth appears to be
about 46 to 91 or 137 meters (25 to 50 or 75 fathoms).
About a dozen species are living in tropical and subtropical
west American waters.

A recent paper by Boss and Merrill (1328) deals
with the members of the Pandoridae in the western Atlan-
tic and a catalogue of this family was published recently
by the former author (1329)

Key to Subgenera of Pandora (1330)

A. Right valve with 2 teeth or crural lami-
nae.
a. Lithodesma present; right valve
with radial markings .. .
aa; Lithodesma lacking; right valv
smooth or with growth
lines only

Pandorella

Pandora s. s. (13381)

B. Right valve with 3 teeth or crural lami-

nae; lithodesma present Heteroclidus

SUBGENUS PANDORELLA CONRAD

Pandorella Conrad, Proc. Acad. Nat. Sci. Philadelphia, Vol.
14, p. 572, 1862 (issued February 17, 1863). Sole
species, “‘P. (Pandora) arenosa, C [onrad].’’ — Vokes,
Jour. Paleo., Vol. 30, No. 3,p. 763, 1956. — K. V. W.
Palmer, Geol. Soc. Amer., Mem. 76, p. 76, 1958. — Boss
and Merrill, Johnsonia, Vol. 4, No. 4, p. 199, 1965.

Kennerlia Carpenter, Rept. Brit. Assoc. Adv. Sci. for 1863,
pp. 602, 638, August, 1864. Reprint in Smithsonian
Mise. Coll., No. 252, pp. 88, 124, 1872. — Stoliczka,
Mem. Geol. Surv. India, Palaeont. Indica, Ser. 6, Vol.
3, pp. XVI, 61, 1871. “‘Pand. (Kenn.) bicarinata, Car-
penter, is the type of the sub-genus.”’

Type species (by monotypy). — Pandora arenosa
Conrad [Jour. Acad. Nat. Sci. Philadelphia, Vol. 7, p. 130,
1834. “Locality. Yorktown, Va.” Miocene. See also Gard-
ner, U.S. G. S., Prof. Paper 199-A, p. 45, pl. 10, figs. 16,
19, 20, 1948 (as Pandora (Kennerlia) arenosa Conrad).
See also Boss and Merrill, 1965, p. 200, pl. 122, figs. 1, 2;
pl. 125, fig. 3.]

Range. — Miocene to Recent.

Description. — Like Pandora, s. s., but with a litho-
desma; right valve with fine but widely spaced and some-

335

what irregular radial striae. (Grant and Gale, Mem. San
Diego Soc. Nat. Hist., Vol. 1, p. 260, 1931, for Kennerlia
Carpenter.)

Remarks. — Adequate reasons for replacing Kenner-
lia by the earlier Pandorella were given by both Vokes and
by K. V. W. Palmer.

Dall, 1921, listed seven species and subspecies of this
subgenus living in the eastern Pacific between Bering Sea
and San Diego, California, and three or four species have
been reported in the Panamic fauna. Four Recent species
were reported from the western Atlantic by Boss and
Merrill.

Pandora (Pandorella) bilirata Conrad
Plate 47, Figure 1; Plate 48, Figures 14, 17, 18

Pandora bilirata Conrad, Proc. Acad. Nat. Sci. Philadel-
phia, Vol. 7, No. 7, p. 267, May 1855. — Conrad, U. S.
Pacific Railroad Expl., Vol. 6, Pt. II, Geol. Rept., No.
2, p. 73, pl. 5, fig. 25, 1857. “Santa Barbara, Cal.”
[Probably Pleistocene according to Keen and Bentson,
Geol. Soc. Amer., Spec. Papers No. 56, p. 80, 1944.]
— I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol.
Sci., Vol. 1, p. 89, pl. 53, figs. 8, 9, 1924 (under sub-
genus ““Kennerlyia’’). “Range. Forrester Island, Alaska,
to Point Abreojos, Lower California.’’ Recent. — Grant
and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p.
261, 1931. Various localities, Pleistocene and Recent.

Type specimen. — Location of the type specimen
not known to the present authors.
Type locality. — “Locality. — Oceurs with the pre-

ceding” [which is Cemoria crucibuliformis Conrad from
“Locality, California. Dr. Heermann.”’ |

Range. — Middle Pliocene to Recent. Recent from
Drier Bay, Prince William Sound, Alaska, to Point Abreo-
jos, Lower California, in 18 to 260 meters (10 to 142
fathoms).

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Original description. — Oblong, very inequilateral,
contracted anteriorly, convex medially; posterior side with
two distant carinated lines towards the hinge margin which
is straight and not oblique; posterior extremity truncated.
(Conrad. )

Remarks.—One right valve and two (one a fragment)
left valves of Pandora bilirata are present in the collection
from Loc. 305 (LAM). The larger valve is 13 mm long.
This is the first record of the occurrence of this species in
the San Diego Formation. Faustman (1332) reported it
from the Rio Dell Formation, of middle Pliocene age, in
Humboldt Co., northern California.

A similar species, Pandora pseudobilirata Nomura
and Hatai (1333), occurs in Japanese waters. This Japan-
ese form was described as differing from P. bilirata in the
less prominent submarginal ridges on the posterior area.

SUBGENUS HETEROCLIDUS DALL

Heteroclidus Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 6, p. 1518, October, 1903.
Type species (by original designation). — “Type

336

Clidiophora punctata Conrad.”

Range. — Miocene (1334) to Recent.

Original description. — Like Clidiophora, but the
long left posterior lamina absent, the right posterior lam-
ina short, and the low anterior right lamina produced; both
the anterior laminae end in front of the anterior adductor
scar; lithodesma present. ( Dall.)

Pandora (Heteroclidus) punctata Conrad
Plate 42, Figures 2, 3, 9, 10

P[andora]. punctata Conrad. Jour. Acad. Nat. Sci. Phil-
adelphia, Vol. 7, Pt. 2, p. 228, pl. 17, fig. 1, 1837. —I.
S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 90, pl. 53, figs. 6,7, 1924. Specimens illus-
trated from San Diego, California, Recent. — Grant
and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p.
262, pl. 13, figs. 2a, 2b, 1931. Specimen illustrated
from “upper San Pedro (Palos Verdes), upper Pleisto-
cene of San Pedro.” Also earlier records cited, ?Mio-
cene to Recent.—Woodring, in Woodring and Bram-
lette, U.S.G.S., Prof. Paper 222, p. 91, pl. 17, fig. 13,
1950. Graciosa Member of Careaga Santsone; “cf.”
in Cebada Member, Santa Maria district, California,
Pliocene. — Morris, A Field Guide to Shells of the Pac-
ifie Coast and Hawaii (Houghton Mifflin Company:
Boston), pp. 25, 61, pl. 8, fig. 11, 1952. Vancouver Is-
land to the Gulf of California, Recent.

Clidiophora punctata Conrad, Arnold, Smithson. Misc.
Coll. (Quarterly Issue), Vol. 50, Pt. 4, pp. 4,27, pl.
56, figs. 2, 3, 1907. ‘‘Graciosa Ridge, near Orcutt,”
California, Pliocene. — J. P. Smith, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 3, p. 171, p. 181 (type error, as Cli-
diophora puctata), 1912. ‘San Diego-Purisima,” Plio-
cene.

Pandora (Heteroclidus) punctata Conrad, Keen, Sea Shells
of Tropical West America (Stanford Univ. Press: Stan-
ford, California), p. 226, fig. 574, 1958. British Colum-
bia to the Gulf of California, Recent.

Type specimen.—British Museum (Natural History).
“1 valve, probably figured holotype” (A. M. Keen, Veli-
ger, Vol. 8, No. 3, p. 172, 1966).

Type locality. — “Inhabits in the neighborhood of
Sta. Barbara. Single valves occur on the beach at the re-
cess of the tide.”

Range. — Middle Pliocene to Recent. Recent from
Vancouver Island, British Columbia, to Cape San Lucas,
Lower California. (Keen.) From below low tide to a depth
of 46 meters (25 fathoms).

Occurrence in San Diego Fm. — C.A.S. Loc. 957,
1178, 1400. L.A.M. Loc. 305C. S.D. Loc. 21. U.C.L.A.
Loc. 1386.

Original description. — Shell much compressed; pos-
terior side produced, extremity rostrated, truncated; liga-
ment margin recurved, sub-margin carinated; within punc-
tate; cardinal teeth three in the superior valve; in the in-
ferior, one elongated oblique tooth. Length, one and a half
inches. [ Length refers to the largest specimen (footnote). ]
(Conrad.)

Remarks. — Several excellently-preserved specimens
of this species are present in collections from the upper
part of the Pliocene section at Pacific Beach. The largest

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

specimen from Loc. 1178 (CAS) is 43 mm long, 23.5
mm high (ventral margin slightly imperfect), the convex-
ity (both valves together), 5.9 mm. Another specimen from
Loc. 21 (SD), is 41.2 mm long, 24.6 mm high, convexity
(both valves together), 7.6 mm. One of the largest Recent
specimens in the collection of the California Academy of
Sciences, from Coronado Beach, California, is 45.5 mm
long. The fossils agree in all observable characters with Re-
cent specimens of Pandora punctata from San Diego. This
species also has been recorded from various localities in
southern California in beds of Pliocene and Pleistocene
age.

The form of P. punctata described as “‘var. Gabbi
Dall”? (1335) from beds of supposed Miocene age was said
to differ from P. punctata in that it lacks the interior
punctations characteristic of the typical form. Woodring
(1950) mentioned that rarely Recent shells have no
punctae.

FAMILY PERIPLOMATIDAE DALL (1336)

Shell subnacreous, conspicuously inequivalve, near-
ly closed, edentulous; the resilium internal, between two
anteriorly or vertically directed chondrophores, often
buttressed, the lithodesma rarely wanting; ligament and
area absent; the beaks fissured, the pallial sinus broad and
shallow; monoecious; marine. (Dall, Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 3, p. 531, 1895.) Late Cretaceous to
Recent.

Lamy (1337) published a paper dealing with many of
the Recent species of this family, and three new generic
names in the Periplomatidae of Australia were proposed by
Iredale (1338). Rosewater (Amer. Malacol. Union, Ann.
Repts. for 1968, pp. 37-39) recently presented an outline
of the classification of this family.

GENUS PERIPLOMA SCHUMACHER

Periploma Schumacher, Essai Nouv. Syst. Habit. Vers
Test. pp. 115, 116, 1817. Sole species, Periploma inae-
quivalvis Schumacher. — Dall, Bull. Mus. Comp. Zool.,
Vol. 12, No. 6, p. 305, 1886. Type P. inaequivalvis
Schumacher. — Lamy, Jour. de Conchyl., Vol. 75, No.
4, p. 303, 1931. “Qui a pour type P. inaequivalvis
Schum. = Anatina trapezoides Lk. = Corbula margar-
itacea Lk.”

Type species (by monotypy). — Periploma inae-
quivalvis Schumacher, 1817, pp. 115, 116, pl. 5, fig. 1.
[For references to this species see Lamy, 1931, pp. 304-
305. ]

Range. — Late Cretaceous to Recent, mostly in
warmer waters. Recent in from 7 to 2295 meters (4 to 1255
fathoms).

Description. — Shell suborbicular to elongate-ovate,
beaks opisthogyrate, the posterior side typically narrower
and shorter. Distinguishing character of the genus is the
large chondrophore found in each valve, strengthened be-
low and behind by a rib or clavicle soldered to the wall of
the shell. Lithodesma, as described above, is seen only in
specimens with tightly closed valves. Surface minutely

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

granulose, most heavily so on the posterior slope, often
faint or absent elsewhere. Surface with plain sculpture of
growth lines, or with concentric undulations as in Cya-
thodonta, or strongly radially ribbed. (Olsson, Mollusks
of the Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), p. 460, 1961.)

Remarks.—Seven species of Periploma have been re-
corded from strata of Tertiary age in California. About
the same number of species now live in west American
waters between Monterey Bay, California, and Peru, only
two ranging into California waters.

Key to Species of Periploma

A. Beaks nearly centrally located stenopa

B. Beaks decidedly nearer the anteriorend . planiuscula

Periploma cf. P. planiuscula Sowerby

The following references to the literature, type spec-
imen, type locality, range and description, refer to typical
P. planiuscula.

Periploma planiuscula Sowerby, Proc. Zool. Soc. London,
for 1834, p. 87, issued October 25, 1834. — I. S. Old-
royd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1,
p. 82, pl. 22, fig. 1, 1924. “San Pedro, California, to
Guayaquil, Ecuador. In the Pleistocene at San Pedro
and San Diego, California.” —Grant and Gale, Mem.
San Diego Soc. Nat. Hist., Vol. 1, p. 225, pl. 13, figs.
la, 1b, 1931. Pliocene to Recent. — Keen, Sea Shells
of Tropical West America (Stanford Univ. Press), p.

229, fig. 585, 1958 (as Periploma planiusculum).‘South-

ern California to Peru, from the extreme low tide level
to depths of a few fathoms.”

Periploma (Periploma) planiuscula Sowerby, Olsson, Moll-
usks of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 463, pl. 82, figs. 2, 2a-e, 196).
Southern California to northern Peru.

Type specimen. — Location unknown to the present
authors.

Type locality. — “Hab. ad Sanctam Elenam.” Ecua-
dor.

Range. — Middle Pliocene to Recent. Recent from
San Pedro, California, to Negritos, Peru, from extreme low
tide to a few meters.

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Original description. — Per. testa oblonga, planius-
cula, inaequivalvi, albicante, impolita, tenuiuscula; latere
antico brevi, subrugoso; marginibus, antica subdeclivi sub-
truncata, dorsali rectiuscula; epidermide tenui, pallescente:
long., 2.4, lat. 0.8, alt. 1.8 poll. (Sowerby.)

Remarks. — Several fragments of a Perpiloma, the
largest about 13 mm long, revealing only the hinge area
retaining the chondrophore, are present in the collection
from Locs. 305 and 305A (LAM). These agree so well
with the corresponding portions of Periploma planiuscula
Sowerby that we refer them, provisionally, to that species.
Sowerby’s species is well known in the Pliocene and Ple-
istocene of southern California and has been reported

337

from strata of Pliocene age in Cosa Rica, Panama, and
Ecuador. Recent specimens 47 mm long and 29 mm high
have been reported from Costa Rica (see Min. Conch.
Club South. Calif. No. 190, p. 21, 1959).

Periploma sanctaecrucis Arnold (1339), a species
of late Miocene or Pliocene age, is a possible precursor of
P. planiuscula.

Periploma teevani Hertlein and Strong (1340) is sim-
ilar to P. planiuscula but the shell is higher in proportion
to the length. Furthermore, the rows of pustules on the
exterior of the valves are arranged in radial rows rather
than the irregular arrangement on P. planiuscula.

Periploma venezuelana wiedenmayeri H. K. Hodson
(1341) with irregular arrangement of pustules is a Ven-
ezuelan Miocene subspecies similar to P. planiuscula.

Periploma stenopa Woodring
Plate 41, Figures 6, 7

Periploma cryphia stenopa Woodring, U. S. G. S., Prof.
Paper 190, p. 57, pl. 9, fig. 7, 1938.

Type specimen. — No. 496106, United States Nat-
ional Museum.

Type locality. — “Union Oil Co. Hellman No. 18
Dominguez field, depth 4,076 feet (U. S. G. S. locality
13899)”. Repetto Formation, early Pliocene.

Range. — Early Pliocene (Repetto Formation) to
middle Pliocene.

Occurrence in San Diego Fm. — L.A.M. Loc. 305A.

Original description. — Larger and more elongate
than cryphia proper and having a more pointed posterior
end. Length 45.2 millimeters, height 33.9 millimeters
(holotype). (Woodring.)

Remarks. — Four specimens of a Periploma, varying
in the degree of preservation, are present in the collection
from Loc. 305A (LAM) near the Mexican boundary.

The best preserved of these, apparently slightly
flattened and the anterior dorsal margin imperfect, is 55.5
mm long, 49.3 mm high, and the convexity (both valves
together), 16.5 mm. The shape and shell characters of the
four specimens agree so well with the original description
and illustration of ‘‘Periploma cryphia stenopa”’ Woodring
that we identify them with that form which we consider
to be a distinct species.

The outline of this species is ovately elongate, the
shell is thin, the beaks nearly centrally located along the
dorsal margin are fissured as is often the case with fossil
specimens of this genus. The anterior end and ventral mar-
gin are rounded. The posterior dorsal margin is nearly
straight and merges into the obliquely rounded posterior
end. A slightly depressed but distinct posterior dorsal area
is present. Sculpture consists of fine concentric lines of
growth.

One specimen is 56.5 mm long, 39.4 mm high, the
convexity (both valves together) 16.4 mm. Another one
is 40.6 mm high, the convexity (both valves together) 20
mm.

The present species differs from Periploma cryphia
Woodring (1342) in the more obliquely rounded posterior
end and apparently in the larger flattened posterior area.
None of the elongate species of Periploma living along the
Pacific coast have the beaks as centrally placed as on this

338

fossil form.

Cochlodesma leana floridana Mansfield (1343), a
species of late Miocene age in Florida, 58 mm long, has a
more steeply sloping posterior dorsal margin and a less
flattened posterior area than that of P. stenopa.

The elongate shape and nearly centrally placed beaks
of the present species in general are similar to those char-
acters on some species of the genus Cochlodesma Couth-
ouy (1344). That genus has a broad, blunt buttress to the
chondrophore and below it a very thin supplementary one.
This is different from the long thin buttress which Wood-
ring stated is present on P. cryphia. Until the character of
the buttress of P. stenopa is known to be referable to
some genus other than Periploma, it seems best to leave it
in the genus under which it was originally described.

FAMILY THRACIIDAE STOLICZKA (1345)

Shell earthy and cellulo-crystalline, not nacreous;
inequivalve, thin, edentulous, often with a granular sur-
face; ligament and resilium chiefly external, opisthodetic,
parivincular, seated on posteriorly directed ny mphae; area
none, beaks usually entire; nearly closed valves, pallial sin-
us present. (Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt.
3, p. 531, 1895.) Jurassic to Recent.

Remarks. — The members of this family occur at the
present time in all seas. Some nestle in holes in rocks or
in other available cavities whereas others occur on mud to
depths of 3600 meters (1968 fathoms), but usually in
shallower water.

A paper by Lamy (1346) deals with the Recent
species of Thraciidae in the Natural History Museum in
Paris and a paper by Soot-Ryen (1347) contains a good
discussion of the north European species in this family.
A paper by Allen (1348) contains the results of a care-
ful study of the British species of Thracia.

Key to Genera of Thraciidae

A. Shell ornamented by prominent oblique
concentric undulations;
granulose Cyathodonta
B. Shell ornamented only by fine concentric
lines of growth; often with fine

granulation; texture often earthy Thracia

GENUS THRACIA LEACH

Thracia Leach in Sowerby, Min. Conch., Vol. 5, No. 72,
p. 20, July 1, 1823. [No species cited.] — Blainville,
Dict. Sci. Nat., Vol. 32, p. 347, 1824. Species cited:
division “SA” with ““Thracia corbuloidea” and division
“B” with “T. pubescens Leach Mya pubescens. Linn.”
— Arkell, Palaecontogr. Soc. London, Vol. 89, British
Corrall, Lamell., Pt. IX, p. 354, 1936. ““Type: Mya
pubescens. Linné.”» — Vokes, Jour. Paelo., Vol. 30,
No. 3, p. 763, 1956.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Type species (designated by Anton, Verzeichniss der
Conehylien, p. 2, 1839). — Thracia “pubescens Lam.”
[= Mya pubescens Pultenye, Cat. Birds, . . . Shells, ...
Plants, . . . Doresetshire, ed. 1, p. 27, 1799. ““Dredged up
at Waymouth” [Weymouth]. For synonymy and refer-
ences to this species see Lamy, Jour. de Conchyl., Vol.
75, No. 3, pp. 217-220, 1931. England to the Mediter-
ranean, Senegal, and Canary Islands. Good illustrations of
this species were published by Soot-Ryen, Tromsd¢ Mus.
Arshefter (Naturhist. Avd. Nr. 17), Vol. 61, No. 1, pl. 5,
figs. 1, 2; pl. 7, fig. 4; pl. 9, fig. 8 a-c, 1941.]

Range. — Typical Thracia, Eocene to Recent and
perhaps Triassic to Recent. Recent in from 5 to 3600
meters (3 to 1968 fathoms).

Description. — Shell concentrically striated, with
more or less fine superficial granulation and a very deli-
cate periostracum; subrostrate, slightly gaping behind;
slightly inequivalve, the right valve larger; the beaks in con-
tact and usually perforated by friction on each other,the
hinge-plate fissured below them and edentulous; the liga-
ment external, the resilium more or less sunken and with,
in most cases, a short, transverse lithodesma in front of it,
occupying the fissure in the hinge-plate; pallial line with a
moderate sinus, margins of the valves entire; the nymphs
in the typical forms do not project greatly from the hinge-
margin ventrally and more or less elongated; the shell is
destitue of nacre. (Dall, Trans. Wagner Free Inst. Sci., Vol.
3, Pt. 6, p. 1523, 1903.)

Remarks. — Blainville was the first author to assign
species to the genus Thracia in 1824. He proposed two
divisions, ‘‘A”’ with a chondrophore in one valve, repre-
sented by T. corbuloidea, and the other “B” with a chon-
drophore in each valve, represented by T. pubescens.
Later Blainville (1349) stated that his division ‘‘B” should
be suppressed because the species which he cited was not
correctly identified. This procedure, if valid, would leave
T. corbuloidea as type of Thracia, as stated by Keen
(1350). However, under the Internat. Rules Zool. Nom-
encl., such action by an author has no validity in nomen-
clature.

Anton, 1839, designated Thracia pubescens “Lam.”
as type species of Thracia. Although he attributed this
species to Lamarck, rather than to Pulteney, his designa-
tion of type species is the earliest for this genus. Deshayes
(1351), 1830, evidently considered this same species
(attributing it to Linnaeus) to be the type of Thracia but
he did not definitely so designate it.

Four species of Thracia have been recorded from
strata of Pliocene age in western North America and a
new species here described occurs in the San Diego Forma-
tion. About an equal number have been described from
pre-Pliocene strata in the same region. Bight species have
been reported living in west American waters between the
Bering Sea and northern Peru.

A paper by Kamada (1352) dealing with the Terti-
ary species of Thracia in Japan appeared recently. Some
of these Oriental species are similar to west American
Tertiary forms.

Thracia kanakoffi n. sp.
Plate 42, Figures 11, 13, 14, 15

Description. — Shell large, thin, valves slightly

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

unequal, nearly equilateral, moderately convex; anterior
margin sloping rather steeply and rounding into the
broadly rounded base, the posterior dorsal margin sloping
very gently downward to the slightly rounded truncated
posterior end; a well-developed umbonal ridge delimits the
posterior end; anterior to this is a well developed radial
depression on the right valve but on the left valve a corre-
sponding depression is much less developed; a narrow but
distinct ridge is present just below and diverging slightly
from the posterior dorsal margin on the right valve; sculp-
ture consisting of incremental lines of growth, a few slight
concentric furrows on the umbos, and over most of the
shell especially toward the base, granulations are rudely
concentrically arranged except toward the ventral margin
where they may assume a rude radial arrangement; on the
posterior dorsal area the rows of granulations often
coalesce to form beaded threads which are rudely concen-
tric but sometimes form interlacing patterns. Dimensions
of holotype: length, 81 mm, height, 54.2 mm, convexity
(both valves together) 32 mm, beak approximately 39 mm
from anterior end.

Type specimen. — Holotype and two paratypes from
Loc. 291 (LAM), silt beds exposed in a gully in the center
of the south half of Sec. 27, T. 4 N., R. 15 W., San Bernar-
dino Base and Meridian; one half mile south of the
Humphrey railroad station, Los Angeles Co., California;
Pico Formation, middle Pliocene.

One paratype is 93 mm long, 70.4 mm high, con-
vexity (both valves together) 38 mm. The other in which
the hinge of the right valve is exposed is 93 mm long and
68 mm high. On a specimen 96.5 long, the pallial sinus
extends anteriorly 39 mm, on another specimen 74 mm
long the pallial sinus extends anteriorly 34 mm from the
posterior end of the valve.

Occurrence in San Diego Fm. — C.A.S. 1419.
L.A.M. 107, 305. S.D. 34.

Remarks.—Over fifty specimens from the type local-
ity have been available for study. These range in length
from 5 mm to 96.5 mm. The hinge, where exposed,
appears to be that of typical Thracia.

This new species bears considerable resemblance to
Thracia trapezoides Conrad (1353) but it differs in the
less steeply sloping posterior dorsal margin, in the presence
of a narrow ridge just below and gently diverging from the
posterior dorsal margin of the right valve, and in the less
developed radial depression just anterior to the posterior
umbonal angulation on the valves.

The present form attains a huge size. A cast, some-
what compressed, lacking the shell, from Loc. 107
(LAM) is 132 mm long and 86 mm high.

The largest specimen of Thracia trapezoides from
Puget Sound in the collection at Stanford University is
67 mm long. The largest specimen of the latter species
among a series from the Timm’s Point Formation, Loc.
130-7 (LAM), of late Pliocene or early Pleistocene age, is
60.4 mm long. This species is reported living in west Ameri-
can waters from Craig, Alaska, to Redondo Beach, Cali-
fornia, in 64 to 173 meters (35 to 75 fathoms), in mud.

Thracia kakumana Yokoyama as illustrated by
Kamada (1354) from strata of Pliocene age in Japan
attains a length of 80 mm. It bears a resemblance to
T. kanakoffi n. sp., but the anterior end is more broadly
rounded and the surface of the valves is said to lack
granulation.

339

This new species is named for George P. Kanakoff,
formerly Curator of Invertebrate Paleontology, Los Angeles
County Museum, who made an extensive collection of
Pliocene fossils in the San Diego area and who generously
made this materal available for the present monograph.

GENUS CYATHODONTA CONRAD

Cyathodonta Conrad, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 4, p. 155 1849. Sole species, Cyathodonta undu-
lata Conrad. — Lamy, Jour. de Conchyl., Vol. 75, No.
3, p. 215, 1931. “Type: T. undulata Conr.” — Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 459, 1961. “Type species
by monotypy, Cyathodonta undulata Conrad.”

Type species (by monotypy). — Cyathodonta undu-
lata Conrad [Proc. Acad. Nat. Sci. Philadelphia, Vol. 4, p.
156, 1849. Title of article states, “‘Shells are from the
coasts of Lower California and Peru.” ‘East coast of
Lower California,” designated as type locality by Hert-
lein and Strong (Zoolgica, Vol. 31, Pt. 3, No. 8, p. 96,
December 5, 1946). Illustrated by Keen, Sea Shells of
Tropical West America (Stanford Univ. Press), p. 232, fig.
595 (on p. 233), 1958. Southern part of the Gulf of
California to Peru.]

Range. — Oligocene to Recent. Recent in from 22
to 73 meters (12 to 40 fathoms), and perhaps deeper.

Description. — Shell broadly ovate to subrectangu-
lar, the anterior side longer, rounded, the posterior side
shorter, depressed, and subtruncate; beaks entire, not
fissured by contact with each other: cardinal plate not
fissured; ligamental myophores short, rounded, project-
ing with a thin, semicircular lithodesma suspended verti-
cally in front of them. Surface sculptured with strong
concentric, sometimes oblique, wave-like plications or
undulations; surface granulose. (Adapted from Lamy,
1931 (free translation), and Olsson, 1961.)

Remarks. — The shell of Cyathodonta differs from
that of Thracia in the strong, obliquely concentric corru-
gations of the valves and in the strongly granulose surface,
the granules often arranged in a definite pattern.

The first appearance of this genus in west American
Tertiary strata is that of Cyathodonta weaveri Clark
(1355) in the San Ramon Formation often assigned late
Oligocene age, in west central California. Species also have
been recorded from beds reported to be of Oligocene age
in Mississippi and Porto Rico and in beds of Miocene age
in the Caribbean region, in Costa Rica, and in Panama.
“Cyathodonta sp.”’ has been recorded from beds of late
Miocene age (Neroly) in southern California by Eaton,
Grant, and Allen (1356). This genus also is present in beds
of Pliocene and of Pleistocene age in southern California
and in Lower California and in the Pleistocene of Panama.

Five, possibly six, species and subspecies live in west
American waters between Monterey, California, and Peru,
and the Galapagos Islands. Two of these range north into
southern Californian waters.

Cyathodonta sp.

Occurrence in San Diego Fm. — L.A.M. 104, 305.

340

Remarks. — A species of Cyathodonta is represented
by several fragments at Loc. 305 (LAM). A fragment ofa
right valve, 10.8 mm long, retains the hinge area. The
chondrophore on this and on other fragments projects
downward at an angle of about 45°. In this character as
well as in the numerous rather fine concentric corruga-
tions on the umbo, the fragment resembles Cyathodonta
formosa Nomland (1357) described from upper Etchegoin
Pliocene beds in the San Joaquin Valley. The fragmental
character of the specimens is such as to preclude positive
specific identification.

A portion of a small valve about 10 mm long is ex-
posed in matrix from Loc. 104 (LAM). The corrugated
concentric sculpture of the shell is similar to that of
Cyathodonta but the species represented is open to
question.

ORDER POROMYOIDA PELSENEER
SUPERFAMILY POROMYACEA DALL
FAMILY POROMYACIDAE DALL (1358)

Shell small, thin, rounded or cordate, subequilateral,
umbos central, prosogyrate, posterior side sometimes
angulated, valves closed or nearly so, the interior pearly;
exterior with rows of granules or smooth; ligament exter-
nal, opisthodetic; resilium sub-internal below the ligament,
seated upon a chondrophore, a small lithodesma present;
hinge of right valve with a stout cardinal tooth behind and
above chondrophore in typical genus but teeth nearly
obsolete in the adults of some genera; muscle impressions
subequal, suborbicular, the posterior one slightly smaller;
pallial sinus small or lacking. [Adapted from Dall, East-
man’s ed. of Zittle’s Textbook of Paleontology, Vol. 1, p.
469, 1913, and Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 466,
1961.] Cretaceous to Recent.

Remarks. — The majority of the members of this
family live in deep water, but a few occur no deeper than
55 meters (30 fathoms). These mollusks occur rather
rarely as fossils.

Dall (1359) discussed the systematics of this family
and mentioned the characters by which various supra-
specific units may be separated.

GENUS DERMATOMYA DALL

Dermatomya Dall, Bull. Mus. Comp. Zool., Vol. 18, pp.
448 et seq., 452, May 20, 1889. Sole species, Poromya
(Dermatomya) mactroides Dall. — Dall, Proc. U.S. Nat.
Mus., Vol. 12, No. 773, pp. 289, 291, 1889 (issued
March 7, 1890). — J.Q. Burch, Min. Conch. Club
South. Calif., No. 38, p. 11, August-September, 1944.
“Type (by monotypy) Dermatomya mactroides Dall
1889. — Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), pp. 466,
467, 1961.

Type species (by monotypy). — Poromya (Derma-
tomya) mactroides Dall [ Bull. Mus. Comp. Zool., Vol. 18,
p. 448, May 20, 1889. “It was dredged by the Albatross
off the coast of Ecuador, in 741 fms.’? — Dall, Proc.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

U.S. Nat. Mus., Vol. 12, No. 773, p. 291, pl. 8, fig. 8, 1889,
issued March 7, 1890 (as Dermatomya mactroides). —
Dall, Bull. Mus. Comp. Zool., Vol. 43, No. 6, p. 429, 1908
(as Poromya (Dermatomya) mactroides). Type specimen
said to be the one illustrated in 1889 (1890). Off southern
Chile or western Patagonia in 122, 348, 449 fathoms. See
discussion below under Remarks].

Range. — Middle Pliocene to Recent in eastern
Pacific and Japan, in 55 to 3058 meters (30 to 1672
fathoms), and perhaps deeper.

Description. — Shell small, subovate, subequilateral,
sometimes angulated posteriorly; umbos central, usually
somewhat inflated, prosogyrate; exterior sculptured only
with concentric lines of growth; hinge of right valve with
a stout subumbonal cardinal tooth in front of a rather
wide chondrophore; hinge of left valve with a notch which
received the cardinal in the opposite valve, a small cardi-
nal tooth behind and above the chondrophore; pallial
sinus well developed.

Remarks. — The genus Dermatomya is recorded here
from the San Diego Formation for the first time. Pre-
viously it was reported from beds at Timm’s Point, San
Pedro, California, believed to be of Pleistocene age. The
generally deep water habitat of members of this genus
probably explains the paucity of fossil occurrences. Seven
species live in the waters of the eastern Pacific between
Alaska and Chile and one species or subspecies lives in
Japanese waters.

The type species of Dermatomya, Poromya (Derma-
tomya) mactroides, was first briefly described by Dall
May 20, 1889, and the locality cited off Ecuador in 741
fathoms. The following year a more extensive description
and an illustration of the species was published and three
localities were mentioned on the west coast of Patagonia
and one off Ecuador. The length of the shell in the descrip-
tion and in the illustration was given as 18 mm. In 1908
Dall referred to this species, stated that the type was illus-
trated in 1889 [1890], that it was 10 mm long, and that
it was a Patagonian species. The shell from Ecuador, 18
mm long, was described as a new species, Poromya (Der-
atomya) equatorialis. In the explanation to the plate the
specimen illustrated was indicated as 6.5 mm long rather
than 18 mm as given in the description. The illustration is
that of a shell on which the posterior end is more trun-
cated and the posterior groove apparently more developed
than that shown in the figure by Dall in 1889 [1890].
There is confusion in the records concerning the two
species but this does not affect the conception of the
genus Dermatomya because the shell characters of the
two species are referable to the same supraspecific cate-
gory.

The genus Poromya Forbes (1360) differs from
Dermatomya in that the shell is sculptured with a series
of radial rows of fine granules and it lacks a pallial sinus.
Poromya is much more widely distributed both geologi-
cally and geographically than Dermatomya. It has been
reported from Eocene to Recent. Species referred to
this genus have been described which live in western Bu-
rope, in the Mediterranean, Atlantic, Caribbean, Antarctic,
eastern Pacific, Japan, East Indies, India and East Africa.
Lamy (1361) mentioned a number of species, Recent and
fossil from various localities. Under the genus Poromya,
including three subgenera, Odhner (1362) listed 48 taxa,
Recent and fossil. Some of these are referable to other

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

genera.

One species, Poromya perla Dall, was described
from the Gulf of Panama at a depth of 2323 meters
(1270 fathoms).

The species described as Poromya gabbiana Ander-
son and Martin (1363) from beds of early Miocene age in
San Luis Obispo County, California, was later assigned to
the genus Solecurtus Blainville by Keen and Bentson
(1364).

Tegland (1365) reported “Poromya n. sp.” from
the Blakeley Formation in western Washington which she
believed to be of late Oligocene age. A fossil from the
same area was described by Weaver, (1943, p. 121, pl.
25, fig. 23) under the name of Poromya teglandae but
Addicott (1366) recently assigned that species to the
genus Macoma.

Abbott (Nautilus, Vol. 65, No. 1, p. 33, 1951)
pointed out that a Recent form described as Poromya
oregonensis by Ridewood in 1903, with illustrations of
the gills and internal organs only, and without informa-
tion concerning the locality from which it came, “‘proba-
bly should be considered a nomen dubium”.

Dermatomya tenuiconcha Dall
Plate 56, Figures 6, 7, 10, 11, 13

Poromya (Dermatomya) tenuiconcha Dall, Proce. U.S.
Nat. Mus., Vol. 45, No. 2002, p. 596, June 11, 1913.

Poromya tenuiconcha Dall, Dall, U.S. Nat. Mus., Bull.
112, p. 27, pl. 3, fig. 10, 1921 (under subgenus
Dermatomya). “‘Alaska Peninsula to Coronado Islands,
in deep water.” — I.S. Otdroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 95, pl. 54, figs. 24, 25,
26, 1924. Type locality and range same as cited by
Dall.

Type specimen. —
National Museum.

Type locality. — “In deep water off Monterey Bay,
California.”

Range. — Middle Pliocene to Recent. Recent from
Alaska Peninsula to the Coronado Islands, Lower Calif-
ornia, Mexico, in 50 to 133 meters (30 to 73 fathoms),
one record of 1205 meters (659 fathoms) (see Burch,
J.Q. Min. Conch. Club South. Calif., No. 38, p. 11,
August-September, 1944; and Smith, A.G., and Gordon,
M., Proc. Calif. Acad. Sci., Ser. 4, Vol. 26, No. 8, p. 172,
1948).

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Original description. — Shell small, thin, olivaceous,
the pearly luster showing through the periostracum;
equivalve, inequilateral, anterior end shorter, rounded in
front; posterior end longer, roundly truncate; beaks
prominent, prosocoelous, with a marked but uncircum-
scribed depression in the lunular region in front of them;
interior pearly, brilliant; margins simple, sharp; hinge in
the left valve with a small internal resilium seated on an
inconsepicuous oblique chondrophore, with a notch imme-
diately in front of it, into which fits a projecting denticle
on the corresponding part of the opposite valve. Height,
13; length of shell, 16; anterior portion, 6; diameter, 10
mm. (Dall.)

Remarks. — Dermatomya tenuiconcha is reported

No. 266865, United States

341

here from the San Diego Formation for the first time.
Two valves, probably paired, are 9.7 mm long, 8.2 mm
high, the convexity (both valves together) 6.8 mm. A small
specimen, 5.7 mm long, both valves adhering to each
other, appears to be a juvenile form of this species.

This species is rather rare in collections of Recent
shells and so far as we know it has been reported pre-
viously as a fossil only at Timm’s Point, San Pedro,
California, from strata which Clark (1367) considered to be
of Pleistocene age. According to Burch, it is not uncom-
mon in those beds.

The smooth posterior area, lacking a groove or a
carina, serves to separate D. tenuiconcha from the tropical
D. equatorialis Dall (1368).

A subspecies, D. tenuiconcha soyoae Habe (1369),
described from Japanese waters, is more produced pos-
teriorly than are typical forms of the west American shell.

Another form from Japan, Dermatomya tenuiconcha
sagamiensis Okutani (1370), described as a questionable
variety of the North American species, was said to differ
from the latter in the “somewhat elongated shell, paler
coloration and nearly horizontal chondrophore.”

FAMILY CUSPIDARIIDAE DALL (1371)

Shell subequivalve, rostrate, earthy or cellulo-crys-
talline, rarely with surface granulations; hinge edentulous
or with subumbonal desmodont tuberculation, sometimes
buttressed; ligament subinternal, anterior to the beaks or
obsolete; resilium internal, with a mesial or ventral
lithodesma; area amphidetic or obscure; valves closed ex-
cept at the tip of the rostrum; pallial line simple; the
retraction of the siphons usually effected by the con-
traction of the septum, the latter leaving a scar on the
valves resembling a pallial sinus. (Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 3, p. 536, 1895.) Cretaceous
to Recent.

Remarks. — The family Cuspidariidae is represented
in strata of Tertiary age in California by one genus with
five species in the Eocene and two species in the Pliocene.
The family is here reported for the first time from the
San Diego Formation. In the Recent west American
molluscan fauna 12 species, distributed in four supra-
specific units, live in the region between the Bering Sea
and San Diego, California, and three genera or subgenera
containing six or eight species live in the tropical and sub-
tropical waters in the eastern Pacific.

GENUS CUSPIDARIA NARDO

Neaera Griffith and Pidgeon, ““The Mollusca and Radiata”
in the Animal Kingdom arranged in conformity with
its organization, by the Baron Cuvier, with supple-
mentary additions to each order by E. Griffith and
others (Whittaker and Company: London), Vol. 12,
“Neaera Chinensis” on legend to pl. 22, fig. 5, on p.
598 as ‘“‘Neroea Chinensis, Gray,” plate dated 1833,
whole volume issued 1834.

Not Neaera Robineau-Desvoidy, 1830. Diptera.

Cuspidaria Nardo, Ann. Sci. Regno Lombardo - Veneto,

342

Vol. 10, p. 50, 1840; Rev. Zool., p. 30, 1840. —
Stewart, Acad. Nat. Sci. Philadelphia, Spec. Publ. No.
3, p. 307, 1930. Type, Cuspidaria typus Nardo. — Pra-
shad, Siboga Exped., Pelecypoda, Monogr. 53c, p. 327,
1932. “The genotype is Cuspidaria cuspidata (Olivi).”
K.V.W. Palmer, Geol. Soc. Amer., Mem. 76, p. 78,
1958. Type by original designation Cuspidaria typus
Nardo ms. = Tellina cuspidata Olivi.

Type species (by original designation, see Internat.
Code Zool. Nomen., Art. 30, b). — Cuspidaria typus
Nardo ms., Adriatic Sea [ = Tellina cuspidata Olivi,
Zoologia Adriatica p. 101, pl. 4, fig. 3 (A, B, C), 1792.
Adriatic Sea, Recent. See also Deshayes, Traité Elém.
Conchyl., Tom. 1, Pt. 2, p. 192, pl. 12 bis, figs. 6-8, 1843-
1850 (as Neoera cuspidata) Mediterranean. = Kobelt,
Illustr. Conchylienbuch, Bd. 2, p. 322, pl. 93, fig. 15,
1881 (as Neaera cuspidata). — Sacco, Moll. Terr. Terz.
Piemonte e Liguria, Pt. 29, p. 123, pl. 26, figs. 31-34,
1901. Elveziano; Piacenziano; Astiano. — Dall in Zittel’s
Text-Book of Paleontology, ed. by Eastman (Macmillan
Co.: London), p. 469, fig. 748, 1913. Austria, Miocene].

Range. — Jurassic to Recent. Recent, widely distri-
buted from 26 to 7297 meters (14 to 3990 fathoms).

Description. — Shell small or of medium size, with a
well-rounded, convex, anterior side and a narrowly pro-
duced posterior end. Hinge without cardinal teeth, the
right valve having a strong, posterior, lateral tooth bor-
dered above by a linear socket into which the margin of
the left valve fits. Chondrophore is a narrow, spoon-shaped
plate placed directly under the beak, directed slightly
backward, and similar in both valves. Surface with con-
centric ribbing. (Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 465, 1961.)

Remarks. — Five species living in west American
waters between the Bering Sea and San Diego, California,
were reported under Cuspidaria s.s. by Dall in 1921.
One species lives in deep water off Panama.

Conrad (1372) published a catalogue of the Recent
species known to him in 1869. Kuroda (1373) more
recently discussed the species of Cuspidaria living in
Japan. Eleven species have been reported from that
area.

SUBGENUS CARDIOMYA A. ADAMS

Cardiomya A. Adams, Ann. Mag. Nat. Hist., Ser. 3, Vol.
13, p. 208, March, 1864. — Eames, Philos. Trans. Roy.
Soc. London, Ser. B, Biol. Sci., No. 627, Vol. 235, p.
453, 1951. Type by monotypy, Neaera gouldiana
Hinds.

Type species (by monotypy). — Cardiomya gouldi-
ana Hinds |
London for 1843, p. 77, December, 1843. ‘““Hab. New
Guinea; Cagayan, island of Mindanao; and Bay of Manila,
Philippines: in from seven to thirty fathoms, sandy mud.”
— Hinds, Zool. Voy. Sulphur, Moll., Pt. 3, p. 70, pl. 20,
fig. 17, 1845. — Chenu, Man. de Conchyl., Vol. 2, p. 50,
fig. 208, 1862. — Kobelt, Illustr. Conchylienbuch, Bd. 2,
p. 322, pl. 93, fig. 16, 1878].

Range. — Late Cretaceous to Recent. Recent,
widespread, in 18 to 4380 meters (10 to 2395 fathoms).

Description. — Shell similar to that of Cuspidaria s.s.

= Neaera gouldiana Hinds, Proc. Zool. Soc.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

but with sculpture of radial ribs and larger, more verti-
cally directed chondrophore.

Remarks. — Most of the species described under the
genus Cuspidaria from strata of Tertiary age in California
are referable to the subgenus Cardiomya. Ten species
have been reported living in the eastern Pacific between the
Bering Sea and Ecuador. Six species of this subgenus
have been reported from Japanese waters.

Cuspidaria (Cardiomya) pectinata Carpenter
Plate 57, Figure 14

Neaera pectinata Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, p. 602, 637, issued August, 1864. Reprint
in Smithsonian Misc. Coll., No. 252, pp. 88, 123,
1872. — Carpenter, Proc. Acad. Nat. Sci. Philadel-
phia, Vol. 17, p. 54, 1865. “Hab. - In sinu Pugetiano
junior legit Kennerley.”” “Apud insulam catalinam et
Sanct. Barbaram adultum piscavit Cooper.” — Arnold,
Mem. Calif. Acad. Sci., Vol. 3, p. 181, pl. 18, fig. 11,
1903. Lower San Pedro Series at Deadman Island, San
Pedro, California, Pleistocene.

Cuspidaria pectinata Carpenter, I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 101, 1924
(under section Cardiomya). Type locality, Puget Sound.
Range, Puget Sound to Panama Bay.

Cuspidaria (Cardiomya) pectinata Carpenter, Grant and
Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 265,
pl. 1, figs. 16, 17, 1931. Pleistocene and Recent. —
Hertlein and Strong, Zoologica, Vol. 31, Pt. 3, p. 101,
1946. Cedros Island, Lower California. — K. V. W.
Palmer, Geol. Soc. Amer., Mem. 76, p. 78, pl. 6, figs.
1-5, 1958. Earlier records cited. — Keen, Sea Shells of
Tropical West America (Stanford Univ. Press: Stanford,
California), p. 234, fig. 600, 1958. Puget Sound to
Cedros Island, Lower California.

Type specimen. — No. 4506, United States Nat-
ional Museum.

Type locality. —‘‘Puget Sound Washington (type)”
(see Palmer, 1958, p. 79).

Range. — Middle Pliocene to Recent. Recent from
Puget Sound to Cedros Island, Lower California, in 18 to
82 meters (10 to 45 fathoms). Reported from west of
Mazatlan, Sinaloa, Mexico, in 84 to 92 meters (Parker, R.
H., Vidensk. Medd. Dansk. Naturh. Foren., Bd. 126, p.
162, 1964).

Occurrence in San Diego Fm. — L.A.M. Loc. 305A.

Original description. — “Principal ribs about 12;
beak smooth. Like sulcata. 40-60 fm. ep.’ (Carpenter,
1864.)

Supplementary description. — N. t. globosa, albida,
subdiaphana; epidermide tenui induta; ventraliter antice
producta, postice subito angustato, rostrato; rostro haud
insculpto, duabus inter quinque partes toius longitudinis
aequante; parte globosa acute costata; costis posticis pau-
llum marjoribus, magis distantibus; margines dorsales ver-
sus obsoletis; interstitiis latis, quadratis, minutissime con-
centrice striatis; costis principalibus t. jun. xii, -xv., adulta,
aliis crebre intercalantibus, cire. xxx., quarum primi maj-
ores: intus, lamina cartilaginea curta, sub umbones celata;
dente postico satis elongato, regione adductoris intus cla-
viculato; cicatricibus adductoribus subrotundatis, deorsum

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

sitis; sinu palii parvo, lato: margine a costis pectinato. Long.
.24, lat. .14, alt. .12. (Carpenter, 1865.)

Remarks. — One right valve 7 mm long and 4.2
mm high, is present in the collection of the Los Angeles
County Museum from near the Mexican boundary. The
valve is quite convex and the main portion is sculptured
with about 14 radial ribs which reach the ventral margin.
Some of these ribs develop by dichotomy of the major
ribs and some as intercalaries.

The convexity and number of ribs agrees with that
of Recent specimens of Cuspidaria (Cardiomya) pectinata
from California. Specimens of this species from Puget
Sound are twice as large as those from California but
otherwise appear identical.

Cuspidaria (Cardiomya) californica Dall (1374) was
described as possessing a smaller, proportionally longer
and less inflated shell sculptured with 16 to 20 radial ribs,
with a straighter rostrum ornamented with two strong
radiating lirae. There is variation in a series of specimens of
C. pectinata and as mentioned by Palmer, Carpenter called
attention to the variability in the number of ribs. The re-
lationship of the two species is now known with certainty.

The shell of Cuspidaria (Cardiomya) oldroydi Dall
(1375), described from Puget Sound, was said to be larger
and more inflated than that of C. pectinata but otherwise
the two appear to be very similar.

Vedder (1376) recently reported ‘‘Cardiomya cf. C.
pectinata (Carpenter) from sandstone strata of Pliocene
age northeast of Newport Beach, California.

Simonova (1377) reported a fossil under the name of
Cuspidaria (Cardiomya) pectinata Carpenter from strata
of late Tertiary age in the southeastern part of Sakhalin
Island, but the illustration is not convincing as to the
identity.

FAMILY VERTICORDITDAE STOLICZKA

Shell equivalve, or nearly so, of small size, inflated,
with the beaks incurved, closed all around, more or less
solid, pearly inside; hinge with few cardinal teeth, more or
less obsolete, ligament subinternal or internal; two mus-
cular impressions, pallial line simple. (Tryon, G. W., Jr.,
Struct. and Syst. Conch., Vol. 3, p. 196, 1884.). Paleocene
to Recent.

Remarks. — Members of this family are widely dis-
tributed geographically and geologically. They occur as
early as Paleocene in some regions but the present record
of Verticordia in the San Diego Formation is the earliest
known in western North America.

Kuroda (1378) discussed the Verticordiidae of Japan
and Iredale (1379) proposed a number of genera for spec-
ies of this family living in Australian waters. Soot-Ryen
(1380) recently discussed this family, especially northern
members of the group.

GENUS VERTICORDIA WOOD

Verticordia J. E. Gray, Synop. Contents Brit. Mus., ed.
42, p. 150, 1840. (Nomen nudum. See Iredale, T., Proc.
Malacol. Soc. London, Vol. 10, pp. 299, 309, 1913.)

Verticordia S. Wood in Sowerby, Min. Conch. Great

343

Britain, Vol. 7, p. 67, pl. 639, August 1, 1844. Sole
species, Verticordia cardiiformis J. Sowerby. — S. Wood,
Palaeontogr. Soc. (London), Vol. 24, Eocene Moll.,
Vol. 1, Pt. 4, No. 3, p. 137, 1871. — Dall, Bull. Mus.
Comp. Zool., Vol. 12, No. 6, p. 285, 1886. “The type
of Verticordia as restricted is V. cardiiformis Sowerby
(Min. Conch., pl. 639, 1844). — Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 6, p. 1509, 1903. “Type
Cryptodon verticordia Searles Wood, + Hippagus car-
diiformis Sowerby.”’ — Prashad, Siboga Exped. Monogr.
53c, Lamell., p. 323, 1932. “The Genotype is Verti-
corida cardiiformis Sowerby.”—Olsson and Harbison,
Acad. Nat. Sci. Philadelphia, Monogr. No. 8, p. 68,
1953. “Type by monotypy: Verticordia cardiiformis
Sowerby.”—Stenzel, Krause, and Twining, Univ. Texas,
Bull. Bur. Econ. Geol., Publ. No. 5704, p. 177, 1957.
Type by monotypy.

Type species (by monotypy). — Verticordia cardii-
formis J. Sowerby (on pl. 639, figs. a, b, c, d) cited as
“Hippagus ? cardiiformis” on p. 68 (in the synonymy of
which is “Cryptodon Verticordia, S. V. Wood, Cata. Ann.
and Mag. Nat. Hist. v, vi. 247’’). “‘coralline crag of Sutton.”
[Pliocene.] Illustrated by S. V. Wood, Paleontogr. Soc.
(London), Vol. 4, Monogr. Crag Moll., Pt. 2, p. 150, pl. 12
figs. 18a, 18b, 1850 issued June, 1851 (as Hippagus ver-
ticordius). “‘Coralline Crag, Sutton.” — Tryon, Struct. and
Syst. Conch., Vol. 3, p. 197, pl. 125, fig. 26, 1884.]

Range. — Paleocene (1381) to Recent. Widely dis-
tributed over the world. Recent in from 9 to 4261 met-
ers (5 to 2330 fathoms).

Description. — Shell generally small, suborbicular,
cardiform, equivalve, the beaks strongly prosogyrate above
a deep, entering lunular indentation with thickened mar-
gins. Shell texture heavy, nacreous within and with a thin,
chalky outer layer minutely shagreened. The hinge of the
right valve shows a stout, conical cardinal tooth placed be-
hind the lunular indentation; there are no laterals. Lig-
ament internal, supported by a lithodesma. Pallial line
simple. Sculpture is formed by strong, radial ribs. [ Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res. Inst.:
Ithaca, New York), p. 469, 1961.)]

Remarks. — Fischer (1382) discussed the generic
units Verticordia and Hippagus and the species assigned to
them.

The genus Verticordia is here reported from the San
Diego Formation for the first time.

Two species in west American waters have been
assigned to Verticordia s. s. These are V. aequicostata
Howard (1383) and V. perplicata Dall (1384). One spec-
ies living in this region is placed in the subgenus Tri-
gonulina.

SUBGENUS TRIGONULINA D’ORBIGNY

Trigonulina d’Orbigny in Sagra, Hist. Phys. Pol. et Nat.
Cuba, Vol. 7, Moll., Vol. 2, p. 291, 1846. Sole species,
Trigonulina ornata d’Orbigny. — Dall, Bull. Mus. Comp.
Zool., Vol. 12, No. 6, p. 286, 1886. Type by monotypy.
— Woodring, Carnegie Inst. Washington, Publ. 366, p.
92, 1925. Type by monotypy. — Olsson and Harbison,
Acad. Nat. Sci. Philadelphia, Monogr. No. 8, p. 68,
1953. Type by monotypy.

344

Type species (by monotypy). — Trigonulina ornata
d’Orbigny.

Range. — Eocene to Recent.

Description. — Shell similar to Verticordia, but the
ribs more irregularly and widely spaced on posterior side.
Right valve with a long, posterior lateral socket. (Olsson
and Harbison.)

Remarks. — Only one species, the type of this sub-
genus, has been reported both as a fossil and Recent from
the western Americas but a number of species occur in
other regions.

Verticordia (Trigonulina) ornata d’Orbigny
Plate 43, Figures 23, 26, 27, 31

Trigonulina ornata d’Orbigny in Sagra, Hist. Phys. Polit.
et Nat. Cuba, Vol. 7, Moll., Vol. 2, p. 292, pl. 27, figs.
30, 31, 32, 1853. — Chenu, Man. de Conchyl., Vol. 2,
p. 169, fig. 843, 1862.

Verticordia ornata @’ Orbigny, Dall, Bull. Mus. Comp. Zool.,
Vol. 9, No. 2, p. 105, 1881. “Barbados, 100 fms.”
“Station 19, 310 fms.” “Catalina Island, California, 16
fms. Dall; shell sand, Jamaica, W. I., d’Orbigny.” [Not
the record “China Seas, Adams.”] — I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
103, pl. 54, figs. 15, 16, 17, 18, 1924. “‘Catalina Island,
California, to Panama Bay” and “Antilles.” [Not the
record “Japan.” ] — Grant and Gale, Mem. San Diego
Soc. Nat. Hist., Vol. 1, p. 266, pl. 13, fig. 4, 1931.
Pleistocene and Recent. — McLean, New York Acad.
Sci., Surv. Porto Rico and Virgin Islands, Vol. 17,
Pte Ips 515 ple 10) fig: 55 “Aprils 1951. “Porto
Rico: Mayaguez,” Recent.

Verticordia (Trigonulina) ornata d’Orbigny, Dall, Bull.
Mus. Comp. Zool., Vol. 12, No. 6, p. 290, 1886. Same
localities cited as in 1881. — Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

York), p. 469, 1961. California to Panama; Caribbean,
West Indies to Massachusetts.

Verticordia novemcostata Adams and Reeve, Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 126, pl. 17, fig. 10, 1903.
“Pleistocene. — San Pedro (Arnold)”. Also Recent.

Not Hippagus novemcostatus, Adams and Reeve, Voy.
Samarang, Moll., p. 76, pl. 24, fig. 1, 1850. “‘Hab.
China Sea.”

Type specimen. — British Museum (Natural History.)

Type locality. — ‘“‘Nous l’avons découverte dans le
sable de la Jamaique.”

Range. — Middle Pliocene to Recent. Recent, Mont-
erey Bay, California, to Panama Bay, in 37 to 160 meters
(20 to 88 fathoms). Caribbean region, North Carolina to
the West Indies, in 15 to 1256 meters (8 to 687 fathoms).

Occurrence in San Diego Fm. — L.A.M. Loc. 305.

Original description. — Testa rotundato-ovato, com-
pressa, sordide albida, radiatim 9 costata; costis erectis,
elevatis; latere buccali 6 approximatis; anli externé uni-
costato, in medio 2 approximatis; interstitiis striatis.
(d’Orbigny.)

Remarks. — Several valves of this small, rounded,
pearly shell were collected by G. P. Kanakoff near the
Mexican boundary. The largest specimen is about 4 mm
long.

The shape and the presence of eight or nine ribs,
chiefly on the anterior two thirds of the valves, easily
serve to separate this from other species in the faunal
assemblage at San Diego. This is the first record of this
species from beds of undoubted Pliocene age in western
North America.

Most workers have been unable to detect any con-
stant difference between shells referred to Verticordia
ornata from east and west American waters. The east Amer-
ican species of this group were discussed by Dall in 1886.

Early records of V. novemcostata Adams and Reeve
from western North America are now referred to V. or-
nata. The species described by Adams and Reeve is be-
lieved to be restricted to Oriental waters.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

REFERENCES AND SUPPLEMENTARY DATA

(1) Dall, W. H., “Pelecypoda” in Text-Book of Paleontology by K.
von Zittel, ed. by C. R. Eastman (Maemillan and Co., Ltd., Lon-
don), Vol. 1, pp. 422-507, figs. 637-836, 1913.

(2) Thiele, J., “Handbuch der Systematischen Weichtierkunde”
(Gustav Fischer: Jena), Bd. 2, Teil 3, Classis Bivalvia, pp. 782-948,
figs. 788-867, 1934.

(3) Da Costa, E. M., Elements of Conchology: or, An Introduction
to the knowledge of shells,” Printed for Benjamin White: Lon-
don), pp. I-VI, 1-318, pls. 1-7, 1776.

(4) Haas, F., in Dr. H. G. Bronn’s “Klassen und Ordnungen des
Tierreichs,”’ Bd. 3, Abt. 3, Bivalvia, Teil 2, Lief. 1, pp. 1-208, figs. 1-
150, 1937; Teil 2, Lief. 2, pp. 209-466, figs. 151-165, 1938; Teil 2, Lief.
3, pp. 467-678, figs. 166-207, 1941; Teil II, Lief. 4, pp. 679-909, figs.
208, 209, 1955.

(5) Franc, A., ‘Classe des Bivalves” in Traité de Zoologie. Ana-
tomie, Systématique, Biologie (publié sous la direction de M.
Pierre-P. Grassé; Masson et Cie, Editeurs; Paris), Tom. 5, pp.
1845-2133, figs. 1605-1802, pls. 9, 10, 1960.

(6) Habe, T., “Genera of Japanese Shells,” Pelecypoda, No. 1, pp.
1-96, figs. 1-192, February, 1951; No. 2, pp. 97-186, figs. 193-428,
September, 1951; No. 3, pp. 187-278, figs. 429-730, May, 1952; No. 4,
Pelecypoda and Seaphopoda, pp. I-V, 281-326, figs. 731-770, Janu-
ary, 1953.

(7) Korobkov, I. A., Metodicheskoe Rukovodstvo po tretichynym
Molluskam. Plastinachatozhabernye [Lamellibranchiata] (Lenin-
grad), pp. 1-444, figs 1-62 in text, pls. 1-96, 1954.

(8) Cox, L. R., “Thoughts on the classification of the Bivalvia,”
Proce. Malacol. Soc. London, Vol. 34, Pt. 2, pp. 60-88, figs. 1 and 2,
August, 1960.

(9) Newell, N. D., Classification of the Bivalvia,” Amer. Mus.
Novitates, No. 2206, pp. 1-25, January 29, 1965.

(10) Vokes, H. E., “Genera of the Bivalvia: A systematic and bib-
liographic catalogue,” Bull. Amer. Paleo., Vol. 51, No. 232, pp. 111-
394, June 16, 1967

(11) “Treatise on Invertebrate Paleontology” (R. C. Moore, ed.)
(Geol. Soc. Amer. and Univ. Kansas), Part N, Vol. 1, Mollusca 6,
Bivalvia, pp. I-XX XVIII, N1-N489, figs. D1-D76; Vol. 2, pp. I-II,
N491-952, figs. E1-E276; F1-F32; G1; H1-H2, 1969.

(12) Boggild, O. B., “The Shell Structure of the Mollusks,” D. Kgl.
Danske Vidensk. Selsk. Skrifter, Naturvidensk. og Math. Afd., 9
Raekke, II, 2, pp. 231-326, 15 pls., 10 figs. in text, 1930.

(18) Oberling, J. J., “Observations on some structural features of
the pelecypod shell,’ Mitt. Naturfor. Gesellsch. Bern, Neue Folge,
Bd. 20, pp. 1-60, figs. 1-3, 1964. See also Schenck, H. G., “Literature
on the Shell Structure of Peleeypods,”’ Bull. Mus. Roy. d’Hist. Nat.
Belgique, Tome 10, No. 34, pp. 1-20, 1934; Carter, R. M., ‘On the
nature and definition of the lunule, escutcheon and corcelet in the
Bivalvia,” Proc. Malacol. Soe. London, Vol. 37, Pt. 4, pp. 243-263,
pls. 35-36, figs. 1-6 in text, April, 1967.

(14) For records of depths reported for mollusks see, Clarke,
A.W., Jr., “Annotated list and bibliography of the abyssal marine
mollusks of the world,” Nat. Mus. Canada, Bull. No. 181, pp. 1-114,
maps 1 and 2(front and back), 1962.

(15) Cited as “Familie. Nuculacea”’ by Philippi, 1853; as “Fam.
Nuculacea” by Morch, 18538; and as superfamily Nuculacea by

_ Dall, 1895.

(16) Cited as Family Nuculidae by Gray in Parry’s Second Voy-
age, Suppl. to Ap., p. cexli, 1824.

(17) Schenck, H. G., ‘Classification of Nuculid Pelecypods,” Bull.
Mus. Roy. d’Hist. Nat. Belgique, Tom. 10, No. 20, pp. 1-78, pls. 1-5,
June, 1934.

(18) See Cox, L. R., “The Jurassic Lamellibranch Fauna of Kuchh
(Cutch),’’ Mem. Geol. Surv. India, Palaeo. Indica, Ser. 9, Vol. 3, Pt.
3, pp. 9-25, 1940; also Proc. Malacol. Soe. London, Vol. 33, Pt. 5, p.
208, 1959.

(19) Van de Poel, L., “Structure du test et classification des nu-
cules,” Bull. Inst. Roy. Sci. Nat. Belgique, Tom. 31, No. 3, pp. 1-11,
1955. See also McAllister, A. L., “Preliminary suggestions for a
classification of nuculid bivalves,” Jour. Paleo., Vol. 38, No. 2, pp.
397-400, 1964.

(20) Not represented in the present collection.

(21) See Dall, W. H., Proc. U.S. Nat. Mus., Vol. 66, Art. 17, p. 22,
pl. 29, figs. 4, 10, 1925.

(22) Trueman, E. R., ‘Observations on the ligament of Nucula,”
Proc. Malacol. Soc. London, Vol. 29, Pt. 5, pp. 201-205, figs. 1-3 in
text, August 29, 1952.

(23) See Ford, E., Jour. Mar. Biol. Assoc. U.K., Vol. 18, No. 3, pp.
555-556, March, 1925.

(24) Allen, J. A., “Observations on Nucula turgida Marshall and
N. moorei Winckworth,” Jour. Mar. Biol. Assoc. U.K., Vol. 31, No.
3, pp. 515-527, pl. 1, text figs. 1-8, 1953.

(25) Leionucula Quenstedt, Geol. und Palaeo. Abhandl., N. F., Bd.
18, Heft 1, p. 112, 1930. Type species: Nucula albensis d’Orbigny,
1844. Gault and upper Greensand, Cretaceous.

(26) See Ichikawa, K., and Maeda, Y., Jour. Inst. Polytechnics,
Osaka City Univ., Ser. G, Geoscience, Vol. 4, p. 76, November,
1958.

(27) Nucula quirica Dall, Proc. U.S. Nat. Mus., Vol. 52, No. 2183,
p. 394, December 27, 1916. “Chugachik Bay, Cooks Inlet, Alaska,
in 60 fathoms, gravelly bottom.”

(28) Nucula (Ennucula) quirica Dall, Schenck, Jour. Paleo., Vol.
13, No. 1, p. 33, pl. 5, figs. 17, 19, 20, 22, January, 1939.

(29) Nucula bellotii A. Adams, Proc. Zool. Soc. London, Pt. 24, p.
51, July 30, 1856. “Hab. Arctic Seas (Sir E. Belcher). Mus. Cum-
ing.”—Hanley, Thes. Conch., Vol. 3, p. 162, pl. 229 (Nuculidae, pl.
IV), fig. 128, 1860.

(30) See Nucula (Ennucula) bellotii A. Adams, Schenck, Jour.
Paleo., Vol. 18, No. 1, p. 30, pl. 6, figs. 19, 21; pl. 8, figs. 10, 11, 13, 16-
20, January, 1939.

(31) Fora discussion of species of Eocene age referred to Lamel-
linucula see Freneix and Gorodiski (Mém. Bur. Rech. Géol. et
Minieér, [ Paris], No. 17, p. 7, 1963.)

(32) Nucula (Nucula) suprastriata Carpenter in Arnold, Mem.
Calif. Acad. Sci., Vol. 3, p. 96, pl. 18, fig. 6, June 27, 1903. “Upper
San Pedro series, Los Cerritos,” late Pleistocene. Also other local-
ities.—Schenck, Jour. Paleo., Vol. 13, No. 1, p. 36, pl. 6, figs. 9, 10, 12,
13, 1939.

(33) Nucula paytensis A. Adams, Proc. Zool. Soc. London for
1856, p. 51, (July 30, 1856). “Hab. Payta, Peru. Mus. Cuming.’’—
Sowerby, Reeve’s Conch. Icon., Vol. 18, Nucula, sp. 28, pl. 3, fig. 28,
1870.—Olsson, Mollusks of the Tropical Eastern Pacific (Paleo.
Res. Inst.: Ithaca, New York), p. 56, pl. 1, figs. 1, la, 1b, 1961.
Northern Peru.

(34) Nucula cahwitensis Olsson, Bull. Amer. Paleo., Vol. 9, No. 39,
p. 348 (171), pl. 21 (18), figs. 21-24, June 21, 1922. “Gatun Stage:
Zone G, Saury Creek,” Costa Rica, Miocene.

(35) Nucula venezuelana Weisbord, Bull. Amer. Paleo., Vol. 45, p.
36, pl. 1, figs. 1-6, February 18, 1964.

(36) Schenck, H. G., ‘“Nuculid Bivalves of the Genus Acila,” Geol.
Soc. Amer., Spec. Papers No. 4, pp. 1-149, pls. 1-18, figs. 1-15 in
text, July 18, 1936.

(37) Frizzell, D. L., “Variation in the sculpture of Acila cas-

346

trensis Hinds,” Nautilus, Vol. 44, No. 2, pp. 50-53, 1 illustr., Octo-
ber, 1930.

(38) Heath, H., “The Anatomy of some Protobranch Mollusks,”
Mém. Mus. Roy. d’Hist. Nat. Belgique, Ser. 2, Fasc. 10, pp. 4, 9, et.
seq., pl. 4, figs. 30, 36; pl. 6, fig. 50; pl. 9, figs. 76, 77, May 31, 1937.
See also Hilton, W. A., Jour. Entomol. and Zool., Vol. 11, No. 4, pp.
76, 77, figs. 1-7, 1919.

(39) Khomenko, I. P., “Stratigraphy of the Tertiary Deposits
from Schmidt Peninsula,” Trans. Geol. Oil Inst., Ser. A, Fase. 103,
pp. 30, 66, 73, pl. 3, figs. 5-7, 1938.

(40) Simonova, A. A., “Fauna of the Tertiary Strata from South
Eastern Part of Soviet Sakhalin,” Trans. Geol. Oil Inst., New
Ser., Fase. 18, p. 12, pl. 1, figs. 4, 4a, 1941.

(41) Cited as “Fam. Ledidae” by H. and A. Adams (Gen. Ree.
Moll., Vol. 2, p. 546, 1858), and on p. 660, ‘For ‘Fam. Ledidae,’ read
‘Fam. Nuculanidae’.”

(42) Dell, R. K., “A synopsis of the Nuculanidae with check lists
of the Australian Tertiary and Recent Species,” Rec. Dominion
Mus., Vol. 2, Pt. 3, pp. 123-134, November, 1955.

(43) Verrill, A. E., and Bush, H. J., “Revision of the genera of Le-
didae and Nuculidae of the Atlantic Coast of the United States,”
Amer. Jour. Sci., Ser. 4, Vol. 3, pp. 51-63, 22 figs. in text, 1897; see
also Proc. U.S. Nat. Mus., Vol. 20, No. 1139, pp. 854-885, 1898.

(44) Lembulus Risso, Hist. Nat. l'Europe Mérid., Vol. 4, p. 319,
1826. Type (designated by Gray, 1847): Lembulus rossianus Risso
[ =Arca pella Linnaeus]. Recent, Mediterranean Sea.

(45) Jupiteria Bellardi, Monogr. Nuculidi Terr. Terz. del Pie-
monte e Liguria, p. 20, 1875. Type (designated by Dall, 1898): “L.
concava Bronn.” Pliocene, Italy.

(46) Praesaccella Cox, Mem. Geol. Sury. India, Palaeo. Indica,
Ser. 9, Vol. 3, Pt. 3, p. 32, 1940. 'Type-species:—Nuculana juriana
sp. nov., Divesian, Kachh.” (Nuculana [Praesaccella] ds
Cox, p. 33, pl. 2, figs. 6-9. Jurassic).

(47) Mesosaccella Chavan, Bull. Soc. Géol. France, Sér. 5, Vol 16,
p. 197, 1946. “Type: ‘Leda’ Forsteri Miller (Nucula) Monogr., I,
1847, p. 17, pl. 2, fig. 1; Holzapfel, op. cit., 1889 (Pal. vol. 35), p. 202,
pl. XXI, figs. 13-17, espéce campanienne et maestrichtienne. . .”
(48) See Heath, H., Mém. Mus. Roy. d’Hist. Nat. Belgique, Sér. 2,
Fasc. 10, pp. 5, 6, et seq., pl. 7, figs. 59, 60, 1937.

(49) Letter dated February 18, 1959.

(50) Letter dated February 12, 1959.

(51) Leda (Jupiteria) callimene Dall, Bull. Mus. Comp. Zool., Vol.
43, No. 6, p. 372, pl. 17, figs. 3, 4, October, 1908, “Gulf of Panama,
259 fathoms, mud, bottom temperature 47.4°F.” See also Hertlein
and Strong, Zoologica, Vol. 25, Pt. 4, p. 393, pl. 1, fig. 18, 1940 (as
Nuculana[Saccella] callimene).

(52) eda Lis ia en ee U. S Nat. Mus., Vol. 12, p. 257, pl.
“in 812 and 634 fathoms,
eva and sand near aie Galapagos Telands: Pacific Ocean; tem-
peratures 38. 4° and 40°F.” Description and illustrations repro-
duced by I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 20, pl. 1, figs. 4, 5, 1924.

(53) Leda balboae Brown and Pilsbry, Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 63, p. 362, pl. 27, fig. 8, July 27, 1911. Gatun formation,
Isthmus of Panama. Miocene.

(54) See Saccella calkinsi Moore, U.S.G.S., Prof. Paper 419, p. 56,
pl. 13, figs. 10-13, 1963. Beach cliffs immediate ly south of Wade
Creek, Astoria formation, Oregon.

(55) See Wright, L.A., Bull. Geol. Soc. Amer., Vol. 59, No. 12, Pt. 2,
p. 1390, 1948 (Basal Modelo (?) in Los Angeles County), and
Weaver, C. E., Geol. Soc. Amer., Mem. 35, p. 79, 1949 (Briones
sandstone).

(56) See Trask, P. D., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol.
13, No. 5, pp. 140-141, 1922 (Briones formation), and Barbat, W. F.,
and Johnson, F. L., Jour. Paleo., Vol. 8, No. 1, p. 7, 1934 (late Mio-
cene).

(57) See Simonova, A. A., Trans. Geol. Oil Inst., New Ser., Fase.
18, p. 14, pl. 1, fig. 8, 1941.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(58) See Slodkewitsch, W.S., Paleo. USSR, Vol. 10, Pt. 3, Fase. 19,
Pelecypoda, Pt. 2, p. 84, pl. 8, figs. 2-6, 1938.

(59) Uozumi, S., “Studies on the molluscan fossils from Hok-
kaido. Part II. Genera Yoldia and Portlandia,” Jour. Fac. Sci.
Hokkaido Univ., Ser. IV, Geol. and Miner., Vol. 9, No. 4, pp. 539-
596, pls. 1-7, figs. 1-8 in text, December, 1957.

(60) Ocklemann, W. K., On the Interrelationship and the Zoogeo-
graphy of northern species of Yoldia Moller, s. str. (Mollusca,
Fam. Ledidae) with a new subspecies, Medd. om Grénland, Bd. 107,
No. 7, 32 pp., 2 pls., 1954.

(61) “Yoldia (Kalayoldia) cf. Y. (K.) cooperi Gabb” was reported
from the Astoria formation of middle Miocene age in Oregon (see
Moore, Ellen, J., U.S.G.S., Prof. Paper 419, p. 58, 1963).

(62) See Yoldia (Kalayoldia) oregona Shumard, Hickman, Mus.
Nat. Hist. Univ. Oregon, Bull. No. 16, p. 31, pl. 1, figs. 14, 15, Au-
gust, 1969.

(63) Yoldia supramontereyensis Arnold, Proc. U.S. Nat. Mus.,
Vol. 34, No. 1617, p. 382, pl. 35, fig. 9, August 8, 1908. “Santa Cruz
quadrangle, Santa Clara County, locality No. 4, in ‘Tusk Gully’
near road, 24 miles south of Mayfield,” California. “Upper Mio-
cene.”

(64) Yoldia cooperi tenuissima Clark, Univ. Calif. Publ., Bull.
Dept. Geol., Vol. 11, No. 2, p. 125, pl. 11, fig. 10; pl. 12, figs. 8 and 14,
July 16, 1918. Loc. 798 (Univ. Calif.), San Ramon formation, Oligo-
cene.

(65) Yoldia cooperi ochotensis Khomenko, Trans. Geol. Prospect.
Surv. USSR, Fase. 79, p. 59, pl. 3, figs. 3, 4, 1931. "The Great Ha-
romay River, right bank, excav. No. 2-3.” Supranutovo Series, up-
per Pliocene.—Slodkewitsch, Acad. Sci. USSR, Paleo. Inst., Paleo.
of USSR, Vol. 10, Pt. 3, Fasc. 18, Pt. 1, p. 127, 1938; Fasc. 19, Pt. I,
p. 102, pl. 6, figs. 5, 6, 7, 1938 (as Yoldia ochotensis).

(66) Kamada, Y., Palaeo. Soc. Japan, Spec. Paper No. 8, p. 60,
1962.

(67) Otuka, Y., Bull. Earthquake Res. Inst., Tokyo Imp. Univ.,
Vol. 12, Pt. 3, p. 609, pl. 47, figs. 17, 18, 1934.

(68) Yoldia cooperi Gabb var. kovatschensis Slodkewitsch, Acad.
Sei. USSR Paleo. Inst., Paleontology of USSR, Vol. 10, Pt. 3,
Fasc. 18, Pt. 1, p. 88, 1938; Fase. 19, Pt. II, p. 87, pl. 1, figs. 1, 2, 3,
4, 1938. ‘“Kovatchina Bay, 1.7 km SW of Moroschechnaya River
(western coast of Kamchatka). Upper horizon of Tighil series.”
[? Oligocene. ]

(69) Cited as “Suborder I. Arcacea” by E. Gray, 1857; as “Super-
family Arcacea” by Dall, Trans. Wagner Free Inst. Sci., Vol. 3,
Pt. 3, p. 516, 1895.

(70) Cited as “Familie” “Arcaceae” by Oken, Isis, Jahrg. 1818,
Bd. 2, Heft 10, p. 1681. Also cited as Family 7. Arcae” by Da
Costa, 1776; as “les arcacées” by Lamarck and by Blainville,
1814; as “Familie Arcaceae” by Goldfuss (Handbuch der Zool.,
Abt. 2, p. 609, 1820); as “Arcadae” by Fleming, 1822; as “Divi-
sion” Arcaceae by Bowdich, 1822; as “Arcacea” by Parkinson,
1822; as “Family Arcadae” by Gray (Jour. Parry’s Second Voy.,
ap., p. cexliv, 1824).

(71) See Cox, L. R., Proc. Malacol. Soc. London, Vol. 33, Pt. 5, p
207, 1959.

(72) Reinhart, P. W., “Mesozoic and Cenozoic Arcidae from the
Pacific Slope of North America,” Geol. Soc. Amer., Spec. Papers
No. 47, pp. I-XI, 1-117, pls. 1-15, figs. 1-3 in text, June 16, 1943.
(73) Maury, C. J., “The Recent Arcas of the Panamic Province,”
Palaeontogr. Americana, Vol. 1, No. 4, pp. 163-208, pls. 29-31,
1922.

(74) Hertlein, L. G., and Strong, A. M., “Eastern Pacific Expedi-
tions of the New York Zoological Society. XXXII. Mollusks from
the west coast of Mexico and Central America. Part II. Zoolog-
ica, Vol. 28, Pt. 3, pp. 149-168, pl. 1, December 6, 1943.

(75) Olsson, A. A., Mollusks of the Tropical Eastern Pacific
(Paleo Res. Inst.: Ithaca, New York), pp. 73-108, 1961.

(76) Heath, H., “The Anatomy of the Pelecypod Family Ar-
cidae,” Trans. Amer. Philos. Soc., New Ser., Vol. 31, Pt. 5, pp. 287-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

319, pls. 1-22, August, 1941.

(77) Woodring, W. P., in Woodring, W. P., and Bramlette, M. N.,
U.S.G.S., Prof. Paper 222, p. 81, 1950.

(78) Arca kobeltiana Pilsbry, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 56, p. 559, pl. 40, figs. 16, 17, 18, 19, August 11, 1904. Cotypes:
“from the east coast of Japan” and “from northern Japan, prob-
ably Yesso.”

(79) Arca boucardi Jousseaume, The Humming Bird, Vol. 4, p.
41, 1894. Lamy, Journ. de Conchyl., Vol. 55, No. 1, p. 44, 1907, and
Kira, T., Illustrations of the Colored Shells of Japan (Hoikusha,
Japan), p. 110, pl. 42, fig. 15 (a-b), 1959. See also a discussion of
the A. boucardi group by Allison, Amer. Malacol. Union, Inc.,
Ann. Repts. for 1964, p. 49.

(80) Arca (Arca) leptogrammica Hall, Jour. Paleo., Vol. 38, No.
1, p. 87, pl. 22, figs. 9, 10, January, 1964. “UCLA fossil loc. 4180;
350 feet north, 1200 feet west from the northwest corner of sec.
1, T. 32S., R. 14 E., 1952 ed. Nipomo Quadrangle, San Luis Obispo
County, California. In fine-grained tuffaceous sandstone and
siltstone—the Phoenix, submember 5, Santa Margarita forma-
tion (Hall, 1962, p. 61).”

(81) See Schenck, H. G., and Reinhart, P. W., “Oligocene arcid
Pelecypods of the genus Anadara,” Mém. Mus. Roy. d’Hi
Nat. de Belgique, Deuxiéme Sér., Fase. 14, pp. 1-73, pls.
figs. 1-12 in text, September 30, 1938. These authors discussed
the genus Anadara and species believed to be of Oligocene age
assigned to it.

According to Endre Széts (Compte Rend. Somm. Séances Soe.
Géol. France, Fase. 8, p. 236, 1962), Anadara is present in the
“Sables de Cassel” which he considered to be of late Oligocene
age. Recently Eames stated, “it is concluded that there are no
pre-Neogene records that can unequivocally be referred to An-
dara (s.s.).” (See Proc. Malacol. Soc. London, Vol. 37, Pt. 4, p. 307,
1967.) More recently, however, Carol Hickman (Mus. Nat. Hist.
Univ. Oregon, Bull. No. 16, p. 33, pl. 1, figs. 16, 17, August, 1969),
published information supporting the record of Anadara from
the Oligocene mentioned by Schenck and Reinhart.

(82) See Mandra, Y. T., “Buttle diatomite, a new member of the
Monterey formation, Salinas Valley, California,’ Guide Book to
the Geology of Salinas Valley and the San Andreas Fault. An-
nual Spring Field Trip, 1963, Pacific Sect. Amer. Assoc. Petrol.
Geol.—Soc. Econ. Paleo. Mineral., p. 104. (Identification of Ana-
dara by L. G. Hertlein).

(83) Iwasaki, Y., ‘Notes on the historical changes of the Japa-
nese Tertiary Anadara,” Venus, Vol. 22, No. 4, pp. 377-389, figs.
land 2 in text, March, 1964.

(84) Adapted from Reinhart, 1943.

(85) See Woodring, W. P., in Woodring, W. P., Stewart, R. B.,
and Richards, R. W., U.S.G:S., Prof. Paper 195, p. 89, 1940
(1941). See also Woodring, W. P., in Woodring, W. P., and Bram-
lette, M.N., U.S.G.S., Prof. Paper 222, p. 82, pl. 9, fige 2:yple a}
fig. 4; pl. 16, fig. 19, 1950.

(86) See Addicott, W. O., “Late Pliocene mollusks from San
Francisco Peninsula, California, and their Paleogeographic sig-
nificance,” Proc. Calif. Acad. Sci., Ser. 4, Vol. 37, No. 3, p. 70,
1969.

(87) See Arca microdonta Conrad, Whiteaves in Dawson, Geol.
‘Surv. Canada, Rept. Prog. for 1878-79, p. 87B, 1880. Skon-un
Point, Graham Island, Queen Charlotte Islands, Canada. Ter-
tiary.
(88) Woodring, W. P., U.S.G.S., Prof. Paper 190, p. 31, 1988. See
-also Woodring, W. P., U.S.G.S., Prof. Paper 195, p. 89, 1940
(1941).
(89) Arca microdonta Conrad, House Document 129, Projected
Vol. III, 33rd Congress, Ist Session, 1855, p. 13. “Loeality.—Tu-
lare Valley? Miocene.”—Conrad, Pac. Railroad Expl., Vol. 5, p.
/323, pl. 3, fig. 29, 1856.—Reinhart, Geol. Soc. Amer., Spec. Papers
47, p. 46, pl. 6, figs. 9, 10, July 16, 1943 (as Anadara (Anadara?2)
“microdonta). {Illustration of type specimen].

347

(90) Anadara? microdonta Conrad, Weaver, Univ. Washington
Publ. Geol., Vol. 5, Pt. 1, p. 72, pl. 12, fig. 14, issued December 31,
1943.

(91) See Anadara trilineata Conrad, Hall, Univ. Calif. Publ.
Geol. Sci., Vol. 34, No. 1, p. 51, pl. 1, figs. 6, 7, 1958.

(92) Arca devincta Conrad, U.S. Explor. Exped. under com-
mand of Charles Wilkes, Vol. 10, Geol., Ap. 1, p. 726, pl. 18, figs.
10, 10a, 1849. “Astoria, Oregon.”—Reinhart, Geol. Soc. Amer.,
Spec. Papers No. 47, p. 43, pl. 6, figs. 6, 8, 1943. [Illustrations of
type specimen.] See also Weaver, Univ. Washington Publ. Geol.,
Vol. 5, p. 72, pl. 12, fig. 16; pl. 18, figs. 4, 8, 1943; Moore, U.S.G.S.,
Prof. Paper 419, p. 59, pl. 13, figs. 14, 15; pl. 14, figs. 1-13, 1963.
(93) Arca montereyana Osmont, Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 4, No. 4, p. 96, pl. 9, fig. 5 (only), 1905. “At Selbys, near
Vallejo Junction.” “Common in the Monterey of the Pinole sec-
tion.”—Reinhart, Geol. Soc. Amer., Spec. Papers No. 47, p. 47, pl.
10, figs. 1, 3, 4, 9, 1943. [As Anadara (Anadara) montereyana.]
(94) Arca devincta montesanoana Etherington, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 20, No. 5, p. 69, pl. 3, figs. 1-5, 7,
8, May 20, 1931. “Type locality.—U.C. Locality 9069.” ‘Mon-
tesano formation, upper Miocene.”

(95) See Hatai, K., and Nisiyama, S., Sci. Repts. Tohoku Univ.,
Sendai, Japan, SecSer. (Geol.), Spec. Publ., Vol. 3, pp. 29-30, 1952.
(96) Arca amicula Yokoyama, Jour. Fac. Sci. Imper. Univ.
Tokyo, See. 2, Vol. 1, Pt. 1, p. 19, pl. 7, figs. 2-4, August 29, 1925;
Makiyama, Palaeo. Soe. Japan, Spec. Paper No. 4, pl. 31, figs. 2,
3, 4; pl. 32, fig. 5, 1958; also Tanaka, T., “Some Observations on
Anadara (s.s.) amicula (Yokoyama),” Venus, Vol. 21, No. 1, pp.
78-92, figs. 1-15 in text; plate 11, 1 table, July, 1960. See also Ana-
dara (Anadara) amicula amicula Yokoyama, Noda, Sci. Repts.
Tohoku Univ., Sendai, Second Ser. (Geol.), Vol. 38, No. 1, p. 83, pl.
5, fig. 8, 1966 and Anadara (Anadara) amicula elongata Noda, p.
84, pl. 5, figs. 2-7.

(97) Kanno, S., “The Tertiary System of the Chichibu Basin,
Saitama Prefecture, Central Japan. Part II Palaeontology,”
(Publ. by the Japan Society for the promotion of Science, Ueno,
Tokyo) pp. I-IV, 123-396, i-ix, pls. 31-51, text figs. 21-26, March,
1960. See especially, p. 205.

(98) Slodkewitsch, W. S., ‘Tertiary Pelecypoda from the Far
East,” Acad. Sci. USSR., Paleont. Inst., Paleontology of USSR.,
Vol. 10, Pt. 3, Fase. 19, Pt. II, p. 105, pl. 11, figs. 7, 7a; pl. 12, figs.
1, 2, 3, 3a, 3b, 19388.

(99) See “Anadara (Anadara) trilineata (Conrad) subsp. n.,”
Krishtofovich, Trudy Vsesoiuznogo Neftianogo Nauchno-issle-
dovatel’skogo Geologorazvedochnogo Instituta (VNIGRI), (Len-
ingrad), Vypusk 232, p. 130, pl. 12, fig. 17, 1964.

(100) Hall (Jour. Paleo., Vol. 38, No. 1, p. 88, 1964) recently re-
ported A. trilineata calcarea from strata of late Miocene age
but we have not seen specimens.

(101) See Richmond, J. F., Calif. State Div. Mines, Spec. Rept.
21, p. 11, 1952.

(102) See Chavan, A., Schweiz. Palaeo. Abhandl., Vol. 69, No. 3,
p. 17, 1952.

(103) See Cucullaearca Conrad, Reinhart, Bull. Mus. Roy d’Hist.
Nat. Belgique, Tome 11, No. 13, p. 27, 1935. Type (designated by
Stoliezka, 1871): Byssoarca lima Conrad. Oligocene of Vicks-
burg, Mississippi.

(104) Abarbatia Dall, Bartsch, and Rehder, Bernice P. Bishop
Mus., Bull. 153, p. 29, July 25, 1938. “Type Barbatia (Abarbatia)
oahua, new species,” p. 30, pl. 5, figs. 1-4, text fig. 10. Kaneohe
Bay, Oahu, in 10 feet of water.

(105) Barbarca Dall, Bartsch, and Rehder, Bernice P. Bishop
Mus., Bull. 153, p. 23, July 25, 1938. “Type: Calloarca (Barbarca)
hua, new species,” p. 24, pl. 4, figs. 5-8, text fig. 8 (a-c). “on the
reef at the entrance to Pearl Harbor, Oahu, on the Honolulu
side.”

(106) Didimacar Iredale, Brit. Mus. (Nat. Hist.), Great Barrier
Reef Exped. 1928-29. Sci. Repts., Vol. 5, No. 6, Moll., Pt. 1, p. 289,

348

February 25, 1939. Type: D. repenta sp. nov.,” p. 289, pl. 3, figs.
24, 24a. “collected north of Cooktown, North Queensland.”

(107) Melvill, J. C., and Standen, R., Proc. Zool. Soc. London for
1906, Vol. 2, Pt. 4, p. 796, 1907.

(108) Barbatia (Fugleria) pseudoillota Reinhart, Jour. Paleo.,
Vol. 11, No. 3, p. 184, pl. 28, figs. 6, 9, 10, April, 1937. ‘‘Pliocene as-
phalt beds at Fugler Point, 7!2 miles southeast of Santa Maria,
Santa Barbara County, California (type).”—Reinhart, Geol. Soc.
Amer., Spec. Papers No. 47, p. 36, pl. 3, figs. (of holotype) 4, 5, 6,
1943.—Woodring, W. P., in Woodring, W. P., and Bramlette, M.
N., U.S.G.S., Prof. Paper 222, p. 82, pl. 15, figs. 12, 18, 1950 (1951).
(109) Arca tenera C. B. Adams, Proc. Boston Soe. Nat. Hist.,
Vol. 2, p. 9, January, 1845. ‘“Jamaica.”—Clench and Turner,
Occas. Papers, Dept. Moll., Mus. Comp. Zool., Harvard Univ., Vol.
1, No. 15, p. 348, pl. 43, figs. 1, 2, 1950. “Jamaica.” See also Ab-
bott, R. T., American Seashells, p. 348, pl. 27, fig. K, 1954.

(110) Arca (Barbatia) balesi Pilsbry and McLean, Notulae Na-
turae, Acad. Nat. Sci. Philadelphia, No. 39, p. 1, text fig. 1 (a, b),
December 22, 1939. ‘Type locality.—Missouri Key, Florida.”
(111) Arca (Acar) millifila Dall, Trans. Wagner Free Inst. Sci.,
Vol. 3, Pt. 6, p. 1629, pl. 56, figs. 21, 24, October, 1903.

(112) Barbatia (Acar) milifilia var. latrinidadis Maury, Bull.
Amer. Paleo., Vol. 10, No. 42, p. 196 (44), pl. 19 (8), fig. 3, March
27, 1925.

(113) Cited as “Family Glycymeridae” by Newton (Jour.
Conch., Vol. 15, No. 3, pp. 81, 88, 1916). Also cited as Family Pec-
tuneulidae (Leach MSS.) Gray, 1847; and as ‘‘Sub-fam. Ax-
inaeinae” by H. and A. Adams, 1858.

(114) Bowden, J., and Heppell, D., Jour. Conch., Vol. 26, No. 2, p.
114, 1966.

(115) See Stenzel, H. B., Krause, E. L., and Twining, J. T., Bull.
Univ. Texas Bur. Econ. Geol., No. 5704, pp. 59-60, 1957. (Family
Glycymerididae placed under a superfamily Glycymeridicae.)
(116) Deshayes, G. P., “Traité Elémentaire des Conchyliologie,”
Tome 1, Pt. 2, p. 124, 1843.

(117) Nicol, D., “Origin of the pelecypod family Glyeymeridae,”
Jour. Paleo., Vol. 24, No. 1, pp. 89-98, pls. 20-22, 2 text figs., Janu-
ary, 1950. é

(118) Nicol, D., “Genera and subgenera of the Pelecypod family
Glycymeridae,” Jour. Paleo., Vol. 19, No. 6, pp. 616-621, two figs.
in text, November, 1945.

(119) Nicol, D., “Distribution of living Glyeymerids with a new
species from Bermuda,” Nautilus, Vol. 70, No. 2, pp. 48-53, pl. 3, 1
map (p. 49), October, 1956.

(120) Baldi, T., ““Glyeymeris s. str. des europdischen Oligozins
und Miozians,” Ann. Hist.-Nat. Mus. Nat. Hungarici, Pars Miner.
et Palaeo., Tom. 54, pp. 85-153, pls. 1-11, illustr. 1-9 in text, 1962.
(121) Chavan, A., “L’Histoire de quelques noms de Coquilles,”
Cahiers Géol., No. 18, pp. 157-160, May, 1953.

(122) Chavan, A., “Observations sur la Structure des Cétes et
sur les Impressions Musculaires des Glycymeris,” Soc. Géol.
France, Compte Rend. Somm., No. 9, pp. 90-92, 3 illustr., 1943.
(123) Veletuceta Iredale, Rec. Australian Mus., Vol. 18, No. 4,
pp. 203, 231, June 29, 1931. “Type Glycymeris flammeus Reeve.”
Illustrated by Reeve, Conch. Icon., Vol. 1, Pectunculus, sp. 7, pl.
2, fig. 7, February, 1843. ‘Hab. — ?”

(124) Glycymerula Finlay and Marwick, New Zealand Geol.
Surv., Palaeo. Bull., No. 15, p. 28, May 20, 1937. “Genotype: Ax-
inaea modesta Angas, Recent, New Zealand, 0-40 fathoms.” II-
lustrated by Marwick, Trans. Proc. New Zealand Inst., Vol. 54,
pl. 5, fig. 6; pl. 6, fig. 6, 1923.

(125) See Glycymeris subobsoleta Carpenter, Palmer, Geol. Soc.
Amer., Mem. 76, p. 63, pl. 1, figs. 8-10, 1958.

(126) Glycymeris corteziana Dall, Proc. U.S. Nat. Mus., Vol. 52,
No. 2183, p. 402, December 27, 1916. "Station 2918 on the edge of
Cortez Bank, California, in 67 fathoms.’’—Willett, Bull. South.
Calif. Acad. Sci., Vol. 42, Pt. 3, p. 113, pl. 11, figs. 2, 2a, 1944
(type).

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(127) Glycymeris migueliana Dall, Proc. U.S. Nat. Mus., Vol. 52,
No. 2188, p. 402, December 27, 1916. “Station, San Miguel Island,
California.”—Willett, Bull. South. Calif. Acad. Sci., Vol. 42, Pt. 3,
p. 114, pl. 11, figs. 5, 5a, 1944 (type).

(128) Glycymeris vancouverensis Clark and Arnold, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 5, p. 187, pl. 27, figs. 2a,
2b, 5, November 6, 1923.

(129) See Arnold, R., “The Paleontology and Stratigraphy of the
Marine Pliocene and Pleistocene of San Pedro, California,”
Mem. Calif. Acad. Sci., Vol. 3, pl. 18, figs. 9, 10, 1903.

(130) Axinaea barbarensis Conrad, Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 8, p. 314, December, 1856. No locality cited. Title
mentions ‘Middle Tertiary Fossils from California.”—Conrad,
U.S. Pac. Railroad Expl., Vol. 6, No. 2, p. 71, pl. 3, fig. 11, 1857
[figure reproduced by Willett, 1946, p. 11, fig. 4.].

(131) In view of Conrad’s reference to fossils of Miocene age, it
is interesting that J. P. Smith (Proc. Calif. Acad. Sci., Ser. 4, Vol.
3, pp. 171, 178, 1912) and Loel and Corey (Univ. Calif. Publ. Bull.
Dept. Geol. Sci., Vol. 22, No. 3, p. 143, 1932), recorded Glycymeris
barbarensis from the Temblor Formation of middle Miocene
age.

(132) Glycymeris tenuimbricata Clark, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 11, No. 2, p. 130, pl. 16, figs. 4, 8, 9, 10, July 16,
1918. From Loc. 1131 (UC), “’ mile SW of town of Walnut
Creek; in creek bed about 100 yards E of Oakland and Antioch
bridge; elevation 150 feet; Contra Costa Co., long. 122°4’8”, lat.
Sepsis .

(133) Glycymeris keenae Willett, Bull. South. Calif. Acad. Sci.,
Vol. 42, Pt. 3, p. 114, pl. 12, figs. 4-7, September-December, 1943,
issued January 15, 1944. “Type locality, Forrester Island,
Alaska.”

(134) Cited as “S. F. Mytilidia” by Rafinesque, 1814.

(135) Cited as “Familie. Mytilacea” by Goldfuss, 1820; as “Divi-
sion XIV. Mytilaceae” by Bowdich, 1822; as “Family: Mytilidae”
by Gray, 1824.

(136) Newell, N. D., “Late Paleozoic pelecypods; Mytilacea,”
State Geol. Surv. Kansas, Vol. 10, Pt. 2, pp. 1-115, pls. 1-15, Octo-
ber, 1942.

(137) See Cox, L. R., Mem. Geol. Surv. India, Palaeont. Indica,
Ser. 9, Vol. 3, pt. 3, pp. 60-62, 1940.

(138) Soot-Ryen, T., “A Report on the Family Mytilidae (Pe-
leeypoda),”” Allan Hancock Pac. Exped., Vol. 20, No. 1, pp. 1-174,
pls. 1-10, text-figs. 1-78, November 10, 1955.

(139) Lutz, G. C., “The Sobrante Sandstone,” Univ. Calif. Publ.
Bull. Dept. Geol. Sci., Vol. 28, No. 18, p. 387, 1951.

(140) Field, I. A., “Biology and Economie Value of the sea mus-
sel Mytilus edulis,” Bull. U.S. Bur. Fish., Vol. 38, pp. 127-259,
figs. 99-230, (Document No. 921), issued July 11, 1922. See also,
Chipperfield, P.N.J., “Observations on the breeding and settle-
ment of Mytilus edulis (L.) in British waters,” Jour. Mar. Biol.
Assoc. U.K., Vol. 32, No. 2, pp. 449-476, text-figs. 1-8, tables I-
XII, 1953.

(141) Seed, R., “Factors influencing shell shape in the mussel
Mytilus edulis,” Jour. Mar. Biol. Assoc. U.K., Vol. 48, No. 3, pp.
561-584, pls. 1 and 2, text-figs. 1-10, October, 1968.

(142) Woodring, W. P., in Woodring, W. P., and Bramlette,
M.N., U.S.G.S., Prof. Paper 222, p. 82, 1950.

(143) Mytilus mathewsonii Gabb Geol. Surv. Calif., Palaeo, Vol.
2, p. 30, pl. 8, fig. 51, February, 1866. “From the Miocene, south
of Martinez” ...—Stewart, Acad. Nat. Sci. Philadelphia, Spee.
Paper No. 3, p. 96, pl. 18, fig. 2, 1930.

(144) Mytilus mathewsonii Gabb var. expansus Arnold, Proce.
U.S. Nat. Mus., Vol. 32, No. 1545, p. 528, pl. 48, fig. 2, June 15,
1907. “Near Torrey Canyon oilwells, southwest of Piru, Ventura
County, California.” “Lower Miocene, supposed equivalent of
the Vaqueros formation.”

(145) Mytilus kewi Nomland, Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 9, No. 14, p. 206, pl. 9, fig. 1, February 24, 1916. “Uni-

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

versity of California, Locality 2680, near top of ridge at center of
NW 14 Sec. 8, T. 22 S, R. 15 E, M.D.B.&M.” “From the Lower
Pliocene.”

(146) Mytilus schencki Hanna and Hertlein, Jour, Paleo., Vol.
12, No. 1, p. 106, pl. 21, fig. 11, January, 1938. ‘From upper part
of Vineyard Canyon in the Southwest corner of the NW 4 SW 4
sec. 23, T. 23 S., R. 13 E., Mount Diablo Base and Meridian, San
Miguel quadrangle, Calif.” “?Santa Margarita formation, Upper
Miocene.”

(147) See Martin, B., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 9,
No. 15, pp. 233, 245, 1916.

(148) See Mytilus (Mytiloconcha) ef. M. (M.) coalingensis Ar-
nold, Glen, Univ. Calif. Publ. Geol. Sci., Vol. 36, No. 2, pp. 159,
169, 1959.

(149) See Clark, B. L., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 8,
No. 22, p. 403 and list opposite pp. 400, 408, 1915.

(150) Brachidontes Swainson, Treatise on Malacology (London),
p. 384, 1840. Sole species, “Suleata. En. Méth. 220. f. 2.”

(151) Hormomya Morch, Cat. Conchyl. Comes de Yoldi, Fase. 2,
p. 538, 1853. Type (designated by Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 4, p. 787, 1898): “Type Mytilus exustus Linné.”
[=Mytilus exustus Linnaeus, Syst. Nat., ed. 10, p. 705, 1758.
“Habitat ad Jamaicam.”’]

(152) Scolimytilus Olsson, 1961, p. 118. "Type species Modiolus
(Brachydontes) playasensis Pilsbry and Olsson.” See p. 119, pl.
18, figs. 2-2c.

(153) Miller, H. W., Min. Conch. Club South. Calif., No. 101, p. 8,
1950.

(154) See Brann, Doris C., Illustrations to Catalogue of the
Collection of Mazatlan Shells” by Philip P. Carpenter, Paleo.
Res. Inst., Ithaca, New York, pl. 15, fig. 168, 1966; also Keen, A.
M., Veliger, Vol. 10, No. 4, p. 392, pl. 55, figs. 5a, 5b, 1968.

(155) See Diener, C., Fossilium Catalogus, 1. Anim., Edit. a C.
Diener, Pars 19, Lamell. Triadica, p. 139, 1923.

(156) Septifer bifurcatus, new variety, obsoletus Dall, Proc. U.S.
Nat. Mus., Vol. 52, No. 2188, p. 404, December 27, 1916. “San
Diego Bay, mud flats.”’ See also remarks concerning this form in
Min. Conch. Club South. Calif., No. 36, p. 11, June, 1944.

(157) Septifer zeteki Hertlein and Strong, Zoologica, Vol. 31, Pt.
2, p. 71, pl. 1, figs. 1 and 2, October 20, 1946. Holotype “from off
Taboga Island, Panama, in 25 fathoms, dredged by James Ze-
tek.”

(158) See Melvill, J. C., and Standen, R., Jour. Conch., Vol. 9, No.
4, p. 104, 1898; Ann. Mag. Nat. Hist., Ser. 8, Vol. 18, p. 128, 1914.
(159) Septifer keeni Nomura, Venus, Vol. 6, No. 4, p. 205, figs.
la-1d, 2-5 December, 1936. “Siogama Bay, Japan (holotype).”
(160) Septifer grayanus Dunker, Commentatio de Septiferis
genere mytilaceorum et de Dreisseniis, (Marburg), p. 5, 1885.
(161) See Habe, T., Gen. Jap. Shells, p. 53, 1951.

(162) Septifer margaritana Nomland, Univ. Calif. Publ. Bull.
Dept. Geol. Vol. 10, No. 18, p. 308, pl. 19, fig. 5, November, 1917.
(163) Mytilus (Modiola) flabellatus Gould, Proc. Boston Soe.
Nat. Hist., Vol. 3, p. 343, December, 1850. “Hab. Puget Sound,
Oregon.”; U.S. Explor. Exped., Vol. 12, p. 453, 1852, Mollusca,
Atlas, pl. 40, figs. 561, 561a, 1856.—See also I.S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sei., Vol. 1, p. 68, pl. 16, fig. 2 (repro-
duction of Gould’s pl. 40, fig. 561), 1924.

(164) Modiolus directus Dall, U.S.G.S., Prof. Paper 59, p. 118, pl.
12, figs. 11, 12, April 2, 1909. “Upper Miocene of Coos Bay, Ore-
gon.” Also cited from “near Fossil Point,” Coos Bay, Oregon,
and “Miocene of the Astoria group, Astoria, Oreg.” [This species
was first cited by Arnold from the Purisimia Formation in Cali-

- fornia, Pliocene, Proc. U.S. Nat. Mus., Vol. 34, No. 1617, p. 354,

August 8, 1908.]

(165) Arnold, R., and Hannibal, H., Proc. Amer. Philos. Soc.,

Vol. 52, No. 212, pp. 588, 590, 1913.

(166) Howe, H. V., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol.
| 14, No. 3, p. 92, 1922.

349

(167) Etherington, T. J., Univ. Calif. Publ. Bull. Dept. Geol. Sci.,
Vol. 20, No. 5, p. 78, pl. 4, fig. 4, 1931.

(168) Weaver,C. E., Univ. Washington Publ. Geol., Vol.5, p. 108, pl.
23, fig. 6; pl. 25, fig. 2, 1942, issued Dec. 31, 1943 (as Volsella directa).
(169) See Moore, Ellen, J., U.S.G.S., Prof. Paper 419, p. 63, pl. 15,
figs. 1, 11, 1963.

(170) Modiolus carpenteri Soot-Ryen, Proc. Malacol. Soc. Lon-
don, Vol. 35, Pt. 4, p. 127, April, 1963. A new name for Modiola
Jfornicata Carpenter, 1864, not Modiola fornicata F.A. Roemer,
1836.

(171) Modiola fornicata Carpenter, Rept. Brit. Assoc. Adv. Sci.
for 1863, p. 643, issued August, 1864. Reprint in Smithsonian
Miscell. Coll., No. 252, p. 129, 1872. Type indicated as from
“Neighborhood of Sta. Barbara” and “Monterey,” California.—
K. V. W. Palmer, Geol. Soc. Amer., Mem. 76, p. 73, pl. 4, figs. 10-
12, 1958 (as Modiolus fornicatus).

(172) Modiolus inflatus Dall, U.S.G.S., Prof. Paper 59, p. 114, pl.
12, figs. 8, 9, 1909. “Miocene of Coos Bay, Oregon.” See also
Moore, Ellen J., U.S.G.S., Prof. Paper 419, p. 63 (in text), 1963.
(173) Modiolus trinominata G D. Hanna, Proce. Calif. Acad. Sci.,
Ser. 4, Vol. 18, No. 10, p. 171, March 18, 1924.

(174) Modiola opifer Say, Jour. Acad. Nat. Sci. Philadelphia,
Vol. 4, Pt. 2, p. 368, pl. 19, fig. 2, a, b, May, 1825.

(175) Modiolaria denticulata Dall, Amer. Jour. Conch., Vol. 7,
pt. 2, p. 154, November 2, 1871. “Habitat, Acapulco, Mexico, Dall,
1868.”

(176) See Gregariella denticulata Dall, Keen, Sea Shells of
Tropical West America (Stanford Univ. Press: Stanford, Cali-
fornia), p. 54, fig. 99, 1958. “ Acapulco, Mexico.”

(177) Crenella coarctata Dunker in Carpenter, Catalogue of the
Collection of Mazatlan Shells, in the British Museum, p. 123, Jan-
uary, 1856. “Hab.—Gallapagos, Cuming.—Mazatlan; in Spon-
dylus caleifer, and burrowing in Murex regius, very rare; L’pool
& Havre Coll.”—Brann, Illustrations to “Catalogue of the Collec-
tion of Mazatlan Shells of Philip P. Carpenter” (Paleo. Res.
Inst.: Ithaca, New York), p. 13, pl. 15, fig. 172, 1966; and Keen,
Veliger, Vol. 10, No. 4, p. 392, text fig. 1, 1968. See also Soot-Ryen,
1955, p. 77, pl. 9, fig. 48; text-fig. 64. Type loc.: Mazatlan, Mexico
(here designated)”; and Olsson, 1961, p. 129, pl. 16, figs. 4, 4a-d.
(178) See Odhner, N. H.-J., The Natural History of Juan Fer-
nandez and Easter Island (Uppsala), ed. by Dr. Carl Skottsberg,
Vol. 3, Zool., Pt. 2, p. 221, 1922.

(179) See Kiihnelt, W., “Bohrmuschelstudien. I.,” Palaeobiol.,
Bd. 3, Lief. 1 and 2, pp. 53-91, pls. 4-11, figs. 1-7 in text, 1930.
(180) See Hodgkin, N., “Limestone boring by the Mytilid Lith-
ophaga,” Veliger, Vol. 4, No. 3, pp. 128-129, pls. 25-27, figs. 1-3 in
text, January 1, 1962.

(181) See Otter, G. W., ‘Rock-destroying organisms in Relation
to Coral Reefs,” Brit. Mus. (Nat. Hist.), Great Barrier Reef Ex-
pedition 1928-29, Sci. Repts., Vol. 1, No. 12, pp. 323-352, pls. 1-6,
figs. 1-5 in text, May 22, 1937.

(182) See Verrill, A. H., “Strange Sea Shells and their stories”
(L. C. Page and Co.: New York), p. 38, 1936.

(183) See Lithophaga plumula kelseyi Hertlein and Strong, Zoo-
logica, Vol. 31, pt. 2, p. 75, pl. 1, figs. 8, 9, August 20, 1946. “San
Diego, California.”

(184) See Lithophaga (Diberus) subula Reeve, Soot-Ryen, Allan
Hancock Pac. Exped., Vol. 20, No. 1, p. 97, pl. 10, fig. 56, 1955.
(185) See Lithodomus subula Reeve, Conch. Icon., Vol. 10, Lith-
odomus, species 26, pl. 4, fig. 26, October, 1857. ‘'Hab.__?”

(186) See Lithophaga plumula Hanley, Willett, Bull. South. Ca-
lif. Acad. Sci., Vol. 45, Pt. 1, p. 29, 1946.

(187) Modiola attenuata Deshayes, Lamarck’s Anim. s. Vert.,
Vol. 7, p. 28, 1836. “Habite au Pérou, au Chile, dans les pierres,”—
I.S. Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p.
73, pl. 39, fig. 10, 1924 (as Lithophaga attenuata). Lower Califor-
nia.—Soot-Ryen, Allan Hancock Pac. Exped., Vol. 20, No. 1, p. 99,
pl. 10, fig. 57, text, fig. 77, 1955 (as Lithophaga (Labis) atte-

350

nuata).

(188) Lithophaga (Labis) attenuata rogersi 5.5. Berry, Leaflets
in Malacology, Vol. 1, No. 14, p. 76, July 19, 1957. ‘“Type-Locality.
Outer reefs of Cholla Cove, Bahia de Adair, Sonora...”

(189) For a collation of this work see Kennard, A.S., and Wo
ward, B.B., ‘Notes on a copy of Capt. Thomas Brown’s Illustra-
tions of the Conchology of Great Britain and Ireland, First
Edition, 1827, in the original wrappers,” Proc. Malacol. Soc. Lon-
don, Vol. 18, Pt. 1, pp. 86-38, April 20, 1928.

(190) Arcoperna Conrad, Amer. Jour. Conch., Vol. 1, No. 2, p.
140, April 15, 1865. Sole species, “A. filosa, nob.,” p. 140, pl. 10,
fig. 14. [In title] ... “Eocene shells from Enterprise, Mis-
sissippi.”

(191) See Van de Poel, L., “Faune Malacologique du Hervien.
Troisieme note (premiére partie), Bull. Inst. Roy. Sci. Nat. Bel-
gique, Tom. 35, No. 15, pp. 1-26, June, 1959. See especially p. 5,
also illustrations of Arcoperna inflata (Miller), Tom. 35, No. 16,
pl. 1, figs. 2a, b. Cretaceous.

(192) “Arvella Bartsch, 1940 ms,” Scarlato, Bivalve Mollusks of
the Far Eastern Seas USSR (Order Dysodonta). Keys to the
Fauna of the USSR, published by the Zoological Institute of the
Academy of Sciences USSR (Acad. Sci.: USSR Press: Moscow;
Leningrad), p. 67, 1960. Type species: Mytilus faba Miiller [Zool.
Danicae Prod., p. 250, 1776.—Reeve, Conch. Icon., Vol. 10, Modz-
ola, species 71, pl. 11, fig. 86, 1858 (as Modiola faba). “Hab.
Greenland.”]

(193) Nuculocardia divaricata d’Orbigny, in Sagra, Hist. Cuba,
Moll., Vol. 2, p. 311, Atlas, pl. 27, figs. 56, 57, 58, 59, 1842. “Se
trouve dans presque toutes les Antilles; au moins l’avons-nous de
la Martinique, de la Guadeloupe, de la Jamaique et de Cuba.”—
Maury, Bull. Amer. Paleo., Vol. 10, Bull. 42, p. 247 (95), pl. 29 (18),
fig. 18, 1925 (as Crenella divaricata). Springvale, Trinidad, Mio-
cene._Warmke and Abbott, Caribbean Seashells (Livingston
Publ. Co.: Narberth, Pennsylvania), p. 161, text fig. 26, 1961.
“Southeast U.S. and the West Indies.”

(194) See Olsson, A. A., Mollusks of the Tropical Eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), p. 130, 1961.

(195) Crenella ecuadoriana Pilsbry and Olsson, Proc. Acad.
Nat. Sci. Philadelphia, Vol. 93, p. 55, pl. 18, figs. 2 and 3, Septem-
ber 9, 1941. ‘‘Canoa formation, Punta Blanca’”’ Ecuador, Pliocene.
See also, Olsson, 1961, p. 180, pl. 17, figs. 7, 7a.

(196) Crenella ecuadoriana santiaga Olsson, “Neogene Mol-
lusks from Northwestern Ecuador” (Paleo. Res. Inst.: Ithaca,
New York), p. 33, pl. 1, fig. 18, October 28, 1964. “Cueva de Ango-
stura.” Miocene.

(197) Crenella caudiva Olsson, Mollusks of the Tropical Eastern
Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 130, pl. 17, fig. 2,
March 10, 1961. ‘Santa Elena, Ecuador.”

(198) See Burch, J. Q., Min. Conch. Club South. California, No.
37, p. 10, July, 1944.

(199) See footnote 201. Cited as “Superfamily Pectinacea” by
Dall, 1895.

(200) Newell, N. D., “Late Paleozoic Pelecypods: Pectinacea,”
State Geol. Surv. Kansas, Vol. 10, pp. 1-128, figs. 1-42 in text,
1937, pls. 1-20, 1937 (issued July 28, 1938). See also Cox, L. R.,
Mem. Geol. Surv. India, Palaeo. Indica, Ser. 9, Vol. 3, Pt. 4, pp. 1+
3, 1952.

(201) Cited as “Family 5. Pectinordae” by DaCosta, 1776; and as
“S.F. Pectenia” by Rafinesque, 1814; as Order Pectenidae by
Fleming, 1822; as ““Pectinideae” by Parkinson, 1822, p. 189, and as
“Pectinidae,” p. 344; as Family Pectenidae by Gray, 1824; as
“Famille” Pectinidae by d’Orbigny, 1839.

(202) Verco, J., “Combing the Southern Seas,” (Adelaide), edit.
by B. C. Cotton, p. 64, 1935.

(203) Kautsky, F., ‘Die biostratigraphische Bedeutung der Pec-
tiniden des Niederésterreichischen Miozins,’ Ann. Naturhis.
Mus. Wien, Bd. 42, p. 245, 1928.

(204) See Jaworski, E., Zeitschr. f. Palaeo., Bd. 1, p. 313, 1913.

LEO GEORGE HERTLKEIN AND U. S. GRANT, IV

(205) Concerning this subject see Moore, H. B., “Ledging” in
Shells at Port Erin, Proc. Malacol. Soc. London, Vol. 21, Pt. 3, pp.
218-217, plate 22, 1934.

(206) See Arkell, W. J., Palaeontogr. Soc. (London), Vol. 90, The
Corall. Lamell., Pt. 10, for 1936, pp. 382-883, issued October, 1937.
(207) See Davies, A.M., “Tertiary Faunas.” (London), Vol. 2, p.
159, 1934.

(208) Bearl, H., ‘The Mollusk and Art,” Nat. Mag., Vol. 26, No.
4, pp. 205-208, 3 figs., October, 1935.

(209) See Cox, I. (editor), “The Scallop, studies of a shell and its
influence on humankind, by eight authors.” Published by the
“Shell” Transport and Trading Company, Ltd., London, pp. 1-
135, illustr. colored including colored end papers, 1957.

(210) Risser, J., “Habits and Life-History of the scallop (Pecten
irradians),”’ Thirty-first Ann. Rept. Rhode Island Comm. Inland
Fish., (Ann. Rept. for 1900), p. 58, 1901. See also Clarke, A.H.,
Jr., ‘The scallop superspecies Aequipecten irradians
(Lamarck),” Malacologia, Vol. 2, No. 2, pp. 161-188, pls. 1-4, figs.
1-6, February, 1965.

(211) Gutsell, J.S. ‘Natural History of the Bay Scallop,” U.S.
Dept. Comm., Bur. Fish., Doe. No. 1100, pp. 569-632, figs. 1-32,
1931. [Concerning annular rings see especially p. 612.] Con-
cerning rings on the shell of Pecten meridionalis Lamarck, see
W.S. Fairbridge, Australian Jour. Mar. Freshwater Res., Vol. 4,
No. 1, pp. 1-40, pl. 1, May, 1953.

(212) Davenport, C.B., “Growth lines in fossil pectens as in-
dicators of past climates.” Jour. Paleo., Vol. 12, No. 5, pp. 514-
515, 1938.

(218) Bazikalova, A., “Age and Rate of Growth of Pecten jes-
soensis Say,” Bull. Acad. Sci., USSR, Ser. 7, Class. Sci. Math.
Nat. for 1934, Nos. 2 and 3, pp. 389-394, 2 figs. [graphs]. [P. 394
(English summary). |

(214) See Fleming, C. A., Jour. de Conchyl., Vol. 90, No. 4, p. 277,
1951.

(215) Jackson R. T., “Phylogeny of the Pelecypoda. The Avicu-
lidae and their allies,” Mem. Boston Soc. Nat. Hist., Vol. 4, pp.
277-400, pls. 23-30, July, 1890. [See especially pp. 333-350. ]

(216) Philippi, E., “Beitrage zur Morphologie und Phylogenie
der Lamellibranchier,” Zeitschr. Deutsch. Geol. Gesell., Jahrg.
1898, pp. 597-622, pl. 19, figs. 1-7 in text; also “Beitrage zur Mor-
phologie und Phylogenie der Lamellibranchier. II. Zur Stamm-
geschichte der Pectiniden,”’ Zeitschr. Deutsch. Geol. Gesell.,
Jahrg. 1900, pp. 64-117, figs. 1-24 in text.

(217) Verrill, A. E., “A study of the Family Pectinidae, with a
Revision of the Genera and Subgenera,” Trans. Connecticut
Acad. Arts and Sci., Vol. 10, Pt. 1, pp. 41-96, pls. 16-21, June,
1897. [ Pp. 41-48, May, 1897, pp. 49-95, June, 1897.]

(218) Sacco, F., ‘I Molluschi dei Terreni Terziarii del Piemonte e
della Liguria, Parte XXIV,” Boll. Mus. Zool. e Anat. Comp. Univ.
Torino, Vol. 12, No. 298, pp. 101-102, June 11, 1897. See also same
title (Torino), Pt. 24, pp. 1-116, pls. 1-21, December, 1897.

(219) Dall, W. H., “Contributions to the Tertiary Fauna of Flor-
ida, with especial Reference to the Miocene Silex Beds of Tampa
and the Pliocene Beds of the Caloosahatchie River,” Trans.
Wagner Free Inst. Sci., Vol. 3, Pt. 4, Pectinidae, pp. 689-758, pls.
26, 29, 34, April, 1898.

(220) von Teppner, W., ‘‘Fossilium Catalogus 1: Animalia. Edit.
a C. Diener. Pars 15: Lamellibranchiata Tertiaria. ‘Ani-
somyaria’ ” (W. Junk: Berlin), pp. 67-296, 1922.

(221) Marwick, J., “The Tertiary Mollusca of the Chatham Is-
lands including a Generic Revision of the New Zealand Pecti-
nidae,” Trans. New Zealand Inst., Vol. 58, Pt. 4, Pectinidae, pp.
445-460, figs. 13-19, 21, 23, 28-31, published separately February
28, 1928.

(222) Dall, W. H., Bartsch, P., and Rehder, H. A., “A Manual of
the Recent and Fossil Marine Pelecypod Mollusks of the Ha-
waiian Islands,” Bernice P. Bishop Mus., Bull. 153, Pectinidae,
pp. 79-96, pls. 19-24, July 25, 1938.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

(223) Iredale, T., “British Museum (Natural History) Great
Barrier Reef Expedition 1928-29 Scientific Reports,” Vol. 5, No.
6, Mollusca, Part 1, Pectinidae, pp. 345-371, pl. 5, February 25,
1939.

(224) Habe, T., “Genera of Japanese Shells,’ Pelecypoda, No. 1,
Pectinidae, pp. 70-84, figs. 135-162, 166-169, February, 1951.

(225) Rowland, H.I., “A Preliminary Survey of Nomenclatural
units of the Tertiary Pectinidae,” Bull. Mus. Roy. d’Hist. Nat.
Belgique, Tome 14, No. 49, pp. 1-9, 1938.

(226) Arnold, R., ‘The Tertiary and Quaternary Pectens of Cal-
ifornia,” U.S.G.S., Prof. Paper No. 47, pp. 1-264, pls. 1-53, figs. 1,
2 in text, 1906.

(227) Hertlein, L.G., ‘‘Pectens from the Tertiary of Lower Cali-
fornia,” Proc. Calif. Acad. Sci., Ser. 4, Vol. 14, No. 1, pp. 1-35, pls.
1-6, July 21, 1925.

(228) Jordan, E.K., and Hertlein, L.G., ‘Expedition to the Revil-
lagigedo Islands, Mexico, in 1925, VII Contribution to the Geol-
ogy and Paleontology of the Tertiary of Cedros Island and
Adjacent Parts of Lower California,” Proc. Calif. Acad. Sci., Ser.
4, Vol. 15, No. 14, pp. 409-464, pls. 27-34, 1 fig. (map) in text, July
22, 1926.

(229) Durham, J.W., “1940 E. W. Scripps Cruise to the Gulf of
California Part II Megascopic Paleontology and Marine Stratig-

raphy,” Geol. Soc. Amer., Mem. 48, Pectinidae, pp. 60-67, pls.

6-14, August 10, 1950.

(230) Tucker, H.I. (later Mrs. Tucker Rowland), ‘“‘Some Atlantic
coast Tertiary Pectinidae,’’ Amer. Midland Nat., Vol. 15, No. 5,
pp. 612-621, pls. 25-27, 1934; “The Atlantic and Gulf Coast Ter-
tiary Pectinidae of the United States,” Amer. Midland Nat., Vol.
17, No. 2, pp. 471-490, pls. 1-4, March 1936; same, Pt. 2, Vol. 17,
No. 6, pp. 985-1017, pls. 5-10, March 1936; Mém. Mus. Roy. d’Hist.
Nat. Belgique,deuxiéme Sér., Fasc. 13, pp. 1-76, pls. 1-6, July 31,
1938.

(231) Mansfield, W.C., “Stratigraphic significance of Miocene,
Pliocene, and Pleistocene Pectinidae in the southeastern United
States,” Jour. Paleo., Vol. 10, No. 3, pp. 168-192, pls. 22-23, 1 fig-
ure in text, April, 1936.

(232) Depéret, Ch., and Roman, F., “Monographie des Pecti-
nidés Néogénes de |’Europe et des régions voisines,’ Mém. Soc.
Géol. France, Paléo., Mém. 26, pp. 1-194, pls. 1-28, 1902-1928
(Mém. Soe. Géol. France, Paléo., Tome 10, Fasc. 1, pp. 1-73, pls. 1-
8, figs. 1-33 in text, 1902; Tome 13, Fasc. 2, pp. 75-104, pls. 9(6)-
11(8), figs. 34-43 in text, 1905; Tome 18, Fasc. 2, pp. 105-139, pls.
12(8)-17(13), figs. 44-60 in text, 1910, Tome 19, Fase. 1, pp. 139-
168, pls. 18(1)-23(6), figs. 61-71 in text, 1912; New Ser., Tome 4,
Fasc. 4, Mem. 10, (continuation of Mém. de Paléo., No. 26), pp.
169-194, pls. 24(20)-28(24), figs. 1-10 in text, 1928).

(233) Roger, J., “Le Genre Chlamys dan les Formations Néo-
genes de l'Europe. Conclusiones Générales sur la Répartition Gé-
ographique et Stratigraphique des Pectinidés du Tertiaire
Récent,’’ Mém. Soc. Géol. France, Nouv. Sér., Tome 17, Fasc. 2-4,
Mém. 40 (completion of Mém. de Paléo., No. 26 and Mém. Nouv.
Sér., No. 10, pp. 1-294, pls. 1(6)-28(33), figs. 1-113 in text, 1939.
(234) Eames, F.E., and Cox, L.R., “Some Tertiary Pectinacea
from East Africa, Persia, and the Mediterranean Region,” Proc.
Malacol. Soc. London, Vol. 32, Pts. 1 and 2, pp. 1-68, pls. 1-20, Au-
gust 31, 1956.

(235) Csepreghy-Meznerics, I., ‘“Pectinidés du Néogéne de la
Hongrie et leur Importance Biostratigraphique,” Mém. Soc.
Géol. France, Nouv. Sér., Tom. 39, Feuilles 15-18, pls. 38-72
(Mém. No. 92, pp. 1-58, pls. 1-35, 1960).

(236) Masuda, K., “Notes on the Tertiary Pectinidae of Japan,”
Sci. Repts. Tohoku Univ., Sendai, Japan, Second Ser. (Geol.),
Spec. Vol. No. 5 (Kon’no memorial volume), pp. 159-193, figs. 1-9
in text, March, 1962; also “Tertiary Pectinidae of Japan,” Sci.
tepts. Tohoku Univ., Sendai, Second Ser. (Geol.), Vol. 33, No. 2,
pp. 117-238, pls. 18-27, figs. 1-11 in text, March, 1962.

(237) MacNeil, F. S., “Cenozoic Pectinids of Alaska, Iceland,

351

and other northern regions,” U.S.G.S., Prof. Paper 553, pp. I-IV,
1-57, pls. 1-25, 1967.

(238) Hertlein, L. G.,‘*The Templeton Crocker Expedition of the
California Academy of Sciences, 1932 No. 25 The Recent Pecti-
nidae,” Proc. Calif. Acad. Sci., Ser. 4, Vol. 21, No. 25, pp. 301-328,
pls. 18, 19, September 26, 1935. See also Hertlein, L. G., and
Strong, A. M., ‘Eastern Pacific Expeditions of the New York
Zoological Society. XXXIV. Mollusks from the West Coast of
Mexico and Central America. Part III.,” Zoologica, Vol. 31, Pt. 2,
pp- 56-62, pl. 1, August 20, 1946.

(239) Grau, G., ‘‘Pectinidae of the eastern Pacific,’ Allan Han-
cock Pac. Exped., Vol. 28, pp. I-VII, 1-308, pls. 1-57, September
25, 1959.

(240) Olsson, A. A., ‘Mollusks of the Tropical eastern Pacific,”
Paleo. Res. Inst.: Ithaca, New York, pp. 1-574, pls. 1-86, March
10, 1961. Family Pectinidae, pp. 155-169, pls. 19-22. See also Ol-
sson, “Neogene Mollusks from Northwestern Ecuador,” Paleo.
Res. Inst.: Ithaca, New York, pp. 33-37, pls. 3-4, 1964.

(241) North, F. K., “The fossil and Recent Pectinidae, their ori-
gin, development, distribution, and classification.” Manuscript,
pp. 1-264, pls. 1-42, 1951. A thesis in partial fulfillment of the re-
quirements for the degree of Doctor of Philosophy, Brasenose
College, Oxford University.

(242) See Noda, H., “The geological significance of the genus
Pecten from the Pliocene Haizume formation, Niigata Pre-
fecture, Japan,” Jap. Jour. Geol. Geogr., Vol. 32, No. 1, pp. 9-17,
pl. 3, March 20, 1961.

It is noted, however, that Kanno reported ‘“Pecten (Notovola)
sp.” from strata referred to late Oligocene age in Japan (see Ma-
suda, K., Sci. Repts. Tohoku Univ., Sendai, Ser. 2 (Geol.), Vol. 33,
No. 2, p. 208, 1962).

(243) Deshayes, G. P., Dict. Class. d’Hist. Nat., Vol. 18, pp. 141-
148, 1828.

(244) Lovell, M. S., ‘The Edible Mollusks of Great Britain and
Ireland with Recipes for Cooking Them” (London), Pectinidae,
pp. 98-114, 1867.

(245) Stearns, R. E. C., “The Pectens, or Scallop-Shells,” Over-
land Monthly for April, 1873, 4 pp.

(246) See Tucker, H. I., Amer. Midland Nat., Vol. 17, No. 2, pp.
473-475, 19386.

(247) See Cox, L. R., Mem. Geol. Surv. India, Palaeo. Indica, Ser.
9, Vol. 3, Pt. 4, pp. 20-21, 1952.

(248) Pecten (Pecten) sanctaecruzensis Arnold, U.S.G.S., Prof.
Paper 47, p. 54, pl. 3, figs. 12, 13, 1906. “on Twobar Creek, one-
fourth mile above its junction with San Lorenzo River, Santa
Cruz County,” California, ‘from beds which appear to be transi-
tional from the Oligocene to the Lower Miocene.” [Concerning
the occurrence and range of this species in the type area see
Burchfield (Jour. Paleo., Vol. 38, No. 2, pp. 404-405, March, 1964).]
(249) See Depéret, C., and Roman, F., 1902, p. 31, pl. 3, figs. 4-7.
(250) See Dakin, W. J., Pecten. Liverpool Mar. Biol. Comm.,
Mem. 17, pp. 1-136, pls. 1-9, figs. 1-4 in text, 1909. (See p. 12.)—See
also, Tang, S.-F., “The breeding of the escallop [Pecten maximus
(L.)] with a note on the growth rate,” Proc. Trans. Liverpool
Biol. Soc., Vol. 54, pp. 9-28, 4 figs. in text, 1941. (See especially pp.
29-28).

(251) See Fleming, C. A., “Ecological Aspects of a Paleontologi-
cal Study,” New Zealand Sci. Rev., No. 5, pp. 60-61, two figs.,
1952.

(252) See Fleming, C. A., “The genus Pecten in the Pacific,”
Jour. de Conchyl., Vol. 90, No. 4, pp. 276-282, pl. 1, January 25,
1951, also “The genus Pecten in New Zealand,” New Zealand
Geol. Surv., Paleo. Bull. 26, pp. 1-69, pls. 1-15, 1957.

(253) Druckerman, D., ‘The genus Pecten in the new world.” A
thesis submitted in partial satisfaction of the requirements for
the degree of Master of Science in Paleontology in the Graduate
Division of the University of California, June, 1961. Pp. I-IV, 1-
119, pls. 1-14, tables 1-3. See especially p. 25.

352

(254) See Pecten (Pecten) bellus variety hemphilli Dall, Durham,
Geol. Soc. Amer., Mem. 43, Pt. 2, p. 60, pl. 7, figs. 3, 5, 1950. From
Loc. 795 (CAS), Punta Santa Antonita, Lower California, middle
Pliocene.

(255) See preceding reference, p. 66, pl. 12, fig. 2; pl. 13, fig. 4.
(256) See Vokes, H. E., in Wilson, I. F., Bull. Amer. Assoc. Pet-
rol. Geol., Vol. 32, No. 9, p. 1788, 1948, also Univ. Nac. Auton. de
Mexico, Inst. Geol. y Geofis. y Geodesia, Bol. No. 53, p. 39,
1948.

(257) Pecten (Pecten) auburyi Arnold, U.S.G.S., Prof. Paper 47,
p. 94, pl. 33, figs. 2, 2a; pl. 34, figs. 2, 2a, 1906. “Pliocene. Locality
38, 1 mile east of the Chandler wells, Puente Hills; Los Angeles
County (Watts).”’ Also from other localities.

(258) Pecten (Pecten) lecontei Arnold, U.S.G.S., Prof. Paper 47,
p. 98, pl. 33, figs. 4, 4a, 4b, 1906. “Pliocene, Cerros Island, Lower
California (University of California).”

(259) Pecten (Pecten) slevini Dall and Ochsner, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 17, No. 4, p. 118, pl. 3, fig. 9; pl. 4, fig. 4,
June 22, 1928. ‘from upper horizon (zone D), on east shore of In-
defatigable Island, Galapagos Group. Probably Pliocene.”

(260) See Pecten (Janira) bellus (Conrad) variety slevini Dall
and Ochsner, Grant and Gale, Mem. San Diego Soe. Nat. Hist.,
Vol. 1, p. 227, pl. 2, fig. 3, 1931. “from locality 258, middle Plio-
cene (oyster-bed facies) north of the Santa Clara Valley and east
of San Martinez Chiquito Canyon, Los Angeles Co.”

(261) See Pecten (Pecten) archon Maury, Bull. Amer. Paleo., Vol.
10, No. 42, p. 236 (84), pl. 27 (16), figs. 2, 3, 5, March 27, 1925.
“Springvale.” “Upper Miocene,” Trinidad.

(262) See Pallium albicans Schroter, Archiv f. Zool. u. Zootomie,
Bd. 3, p. 136, 1802. Illustrated by Kira, “Shells of the Western
Pacific in Color” (Hoikusha Publ. Co.: Osaka, Japan), p. 134, pl.
48, fig. 3, 1962. Southern Hokkaido to Kyfisha, Japan. [This is an
earlier name for Pecten laqueatus Sowerby, Thes. Conch., Vol. 1,
p. 46, pl. 15, fig. 101, 1842. “Brought by Capt. Dixon from N. W.
America.”’ See Rehder, H. A., Nautilus, Vol. 58, No. 2, p. 54,
1954.]

(263) Pecten excavatus Anton, Verzeichniss der Conchylien (Ed-
uard Anton: Halle), p. 19, 1889. Vaterland China.” Illustrated
by Kira, “Shells of the Western Pacific in Color” (Hoikusha Publ.
Co.: Osaka, Japan), p. 134, pl. 48, fig. 2, 1962. “Southern part of
Japan, Formosa and southern China, in shallow waters.”

(264) See Fleming, C. A., Trans. Roy. Soc. New Zealand, Vol. 79,
p. 128, 1951.

(265) Baldi, T. (Ann. Hist.-Nat. Mus. Nat. Hungarici, Vol. 58, pp.
71, 82, 1966), cited Flabellipecten from strata which he believed
to be of late Oligocene age.

(266) See Toula, F., Jahrb. d. K. K. Geol. Reichsanstalt, Bd. 58,
Heft 4, explanation of pl. XX VI (II), fig. 2, 1908.

(267) Pecten (Pecten) hawleyi Hertlein, Bull. South. Calif. Acad.
Sci., Vol. 24, May-August, Pt. 2, p. 40, pl. 4, figs. 4, 5, August 17,
1925. “upper beds of the Vaqueros sandstones, Santa Inez Moun-
tains, Santa Barbara County, California.”

(268) These authors include some species in Flabellipecten which
are referable to Amussiopecten which we consider to be a sepa-
rate subgenus.

(269) Pecten (Pecten) diegensis Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 4, p. 710, April, 1898. "Pleistocene of San Diego;
Hemphill. Living on the adjacent shores from Monterey, Califor-
nia, southward.” A new name for Pecten floridus Hinds (Zool.
Voy. Sulphur, Moll., Pt. 3, p. 60, pl. 17, fig. 6, 1844, January, 1845).
“Inhab. San Diego, California. In five fathoms, among mud.”
[Not Ostrea florida Gmelin, 1791, a Pecten.|—Grau, Allan Han-
cock Pac. Exped., Vol. 23, p. 143, pls. 52, 53, 1959.

(270) Pecten lunaris §.S. Berry, Leaflets in Malacol., Vol. 1, No.
23, p. 139, September 30, 1963. 'Type-Locality: 30-45 fms., off
Morro Colorado, Sonora; Capt. Antonio Luna, Mar. 1963.”

(271) Pecten sericeus Hinds, Zool. Voy. Sulphur, Moll., Pt. 3, p.
60, pl. 17, figs. 1, la, 1844 (January, 1845, on cover of Pt. 3). “In-

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

hab. Bay of Panama. In fifty-three fathoms, on a muddy floor.”
—Grau, Allan Hancock Pac. Exped., Vol. 23, p. 141, pls. 50, 51,
1959.

(272) Pecten (Pecten) carrizoensis Arnold, U.S.G.S., Prof. Paper
47, p. 59, pl. 4, figs. 1, la, 1b, 2, 3, and 3a, 1906. From “the head of
Garnet Canyon, about 12 miles north of the Mexican boundary,
in the Carrizo Creek district, San Diego County.” Miocene.
[Pliocene.] [On page 152 the type is cited as from Alverson Can-
yon. |

(273) Pecten (Pecten) beali Hertlein, Proc. Calif. Acad. Sci., Ser.
4, Vol. 14, No. 1, p. 10, pl. 2, fig. 3; pl. 5, fig. 8, July 21, 1925. “peb-
bly sandstone near Comondu-Salada contact, Arroyo near La
Palma, Lower California.” “Salada, Pliocene.”

(274) Pecten ochlockoneensis violae Tucker, Amer. Midland Nat.,
Vol. 17, No. 2, p. 481, pl. 1, figs. 1, 2, March, 1936. "Jackson Bluff,
Fla. (tvpe).” “Choctawhatchee (Miocene).”

(275) Pecten bései Hanna and Hertlein, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 16, No. 6, p. 154, pl. 5, figs. 2, 3, April 22, 1927. “Loe.
795 (C.A.S.), caftyon about one half a mile inland from Santa An-
tonita Point, Lower California.’’ Pliocene.

(276) See Vokes, H.E., in Wilson, I.F., Bull. Amer. Assoc. Petrol.
Geol., Vol. 32, No. 9, p. 1782, 1948.

(277) Pecten soror Gabb, Pilsbry, Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 73, Pt. 2, p. 410, pl. 44, figs. 1, 2, 1921, issued Janu-
ary 30, 1922.

(278) Pecten soror codercola Harris, Bull. Amer. Paleo., Vol. 13,
Bull. 49, p. 23, pl. 18, fig. 3; pl. 14, figs. 1, 5; pl. 15, fig. 7, October 7,
1927. ‘Districts of Democracia and Colina, State of Falcén, local-
ity numbers 69, 123.” Venezuela. “Miocene and Pliocene.”

(279) See Fitch, J.E., State Calif. Dept. Fish Game, Mar. Fish.
Branch, Fish Bull. No. 90, p. 48, fig. 9, 1953.

(280) See Fleming, C. A., “The genus Pecten in New Zealand.”
New Zealand Geol. Surv., Paleo. Bull. 26, pp. 1-69, pls. 1-15, 1957.

(281) Pecten (Pecten) heimi Hertlein, Proc. Calif. Acad. Sci., Ser.
4, Vol. 14, No. 1, p. 9, pl. 1, fig. 3; pl. 3, fig. 3, July 21, 1925. “south-
ern part of Arroyo San Gregorio, Lower California; ... Lower
Pliocene?.”

(282) Pecten (Pecten) juanensis Grant and Stephenson, Jour.
Paleo., Vol. 22, No. 6, p. 804, pl. 124, figs. 1-4, November, 1948.
“UCLA Locality 435, sandstone fossil reef on east side of valley
of San Juan Creek, at elevation of about 1500 feet above sea
level, in west middle half of section 32, Township 28 south,
Range 16 East (Mount Diablo Base and Meridian), eastern San
Luis Obispo County, California. Stratigraphic position: approx-
imately at conformable contact between lower and upper Ne-
roly, lower half of the upper third of the Miocene.”

(283) Pecten coalingaénsis Arnold in Anderson, Proc. Calif.
Acad. Sci., Ser. 3, Geology, Vol. 2, No. 2, p. 197, pl. 18, figs. 94-98,
December 4, 1905. “This species is common in the Etchegoin
Beds of the Mount Diablo Range, at the Kreyenhagen ranch on
Zapata Chino Creek.” “probably Pliocene.” —Arnold, U.S.G.S.,
Prof. Paper 47, p. 97, pl. 4, figs. 4, 4a, 5, 1906 (as Pecten (Pecten)
coalingaensis).

(284) Pecten (Oppenheimopecten) hancocki Grau, Allan Hancock
Pac. Exped., Vol. 23, p. 154, pl. 57, September 25, 1959. “Chatham
Bay, Cocos Island, Costa Rica, in 47 fathoms, coarse white
sand.”

(285) See Pecten aduncus Eichwald, Depéret and Roman, Mém.
Soe. Géol. France, Paléo., Tome 10, Fase. 1, Mém. No. 26, p. 49, pl.
6, figs. 6, 6a, 1902.

(286) Pecten (Pecten) perulus Olsson, Mollusks of the tropical
Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 158, pl.
20, figs. 3, 8a-c; pl. 21, figs. 3, 3a, March 10, 1961. “Santa Elena,
Ecuador. Holotype, ANSP 218918.”

(287) See Hoffstetter, R., Bol. Inform. Cienc. Nat. (Quito), Vol.
2, Nos. 18, 14, p. 73, 1948.

(288) See Patinopecten sp., Schenck, Univ. Calif. Publ. Bull.

Dept. Geol. Sci., Vol. 18, No. 1, p. 28, 1928. Yaquina sandstone,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

western Oregon.

(289) Akiyama, M., “Studies on the phylogeny of Patinopecten
in Japan,” Sci. Repts. Tokyo Kyoiku Daigaku, Geol. Min. Geogr.,
Sec. C, Vol. 8, No. 74, pp. 63-122, pls. 1-8, figs. 1-3, in text, Febru-
ary 5, 1962.

(290) Masudapecten Akiyama, 1962, p. 107. “Type species. Pa-
tinopecten masudai Akiyama, sp. nov.,” p. 107, pl. 1, fig. 2; pl. 3,
fig. 1, February 5, 1962 (as Patinopecten (Masudapecten) ma-
sudai Akiyama). From the Sugota Formation, Akita Prefecture,
early Miocene.

(291) Masuda, K., “The so-called Patinopecten of Japan,” Trans.
Proc. Palaeo. Soc. Japan, New Ser., No. 52, pp. 145-153, pls. 22,
23, December 10, 1963.

(292) Blanckenhornia von Teppner, Foss. Cat. 1: Anim., Edit. a
C. Diener, Pars 15, Lamell. Tert., Anisomyaria II, p. 260, 1922.
“Typus: Pecten (Blanckenhornia) oweni Arnold.”

(293) See Jaworski, E., Palaeo. Zeitschr., Bd. 1, Heft 2, p. 296,
1914.

(294) Fortipecten Yabe and Hatai, Sci. Rept. Tohoku Imper.
Univ., Sendai, Japan, Ser. 2 (Geol.), Vol. 21, no. 2, p. 149, 1940.
“Type: pl. XXXIV (1), Figs. 4-6.” [= Pecten takahashii Yo-
koyama, 1930.]

(295) Pecten (Patinopecten) lohri Hertlein, Nautilus, Vol. 41, No.
3, p. 93, January, 1928. New name for Pecten (Patinopecten)
owent Arnold, U.S.G.S., Prof. Paper 47, p. 63, pl. 8, figs. 1, 1a, 1b,
1906. “Foxin’s ranch, Santa Barbara County, Cal.” Pliocene.
(Not Pecten oweni DeGregorio, 1884.)—Hanna and Hertlein, Ca-
lif. State Div. Mines, Bull. 118, p. 176, fig. 65-1 (p. 177), 1941. Beds
at railroad bridge across Waltham Creek, about 2 miles south-
west of Coalinga, Fresno Co., California. Jacalitos formation,
lower Pliocene.

(296) The specimen from that region illustrated by the senior
author under the name of Pecten lohri can be referred to P.
healeyt. See Calif. State Div. Mines, Bull. 154, p. 189, fig. 2, (on p.
188), 1951.

(297) Pecten propatulus Conrad, U.S. Explor. Exped. (Wilkes),
Vol. 10, Geol., ap. p. 726, atlas, pl. 18, figs. 13, 18a, 1849. “Astoria,
Oregon.” Miocene. —Arnold, U.S.G.S., Prof. Paper 47, p. 64, pl. 7,
fig. 1; pl. 9, figs. 1, 1a, 2, 2a, 1906 (as Pecten (Patinopecten) propa-
tulus). Moore, U.S.G.S., Prof. Paper 419, p. 64, pl. 16, figs. 1-4;
pl. 17, figs. 2-5, 7, 1963 (as Patinopecten propatulus). (Lectotype.)
(298) Pecten (Patinopecten) haywardensis Lutz, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 28, No. 13, p. 386, pl. 17, figs. 9,
10, October 16, 1951. Hayward quadrangle, California; Sobrante
Sandstone, middle Miocene.

(299) Pecten (Patinopecten) haywardensis calaverasensis Hall,
Univ. Calif. Publ. Geol. Sci., Vol. 34, No. 1, p. 51. pl. 2, fig. 2; pl. 3,
fig. 4; pl. 4, fig. 83, November 24, 1958. ‘Middle Miocene, Oursan
sandstone.”

(300) Pecten oregonensis Howe, Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 14, No. 3, p. 98, pl. 11, figs. 1, 2; pl. 12, figs. 1, 2,
September 8, 1922. Type locality: West side of Coos Head, mouth
of Coos Bay, Oregon. Pliocene. A subspecies, Patinopecten orego-
nensis cancellosus Moore (1963, p. 65, pl. 17, figs. 6, 8, 9; pl. 18,
figs. 1, 4) was described from “Dredgings from the Miocene
rocks, Coos Bay, Oreg.”

(301) Pecten tryblium Yokoyama, Jour. Fac. Sci. Imper. Univ.
Tokyo, See. II, Geol., Vol. 1, Pt. 1, p. 17, pl. 6, figs. 1, 2; pl. 7, figs.
1,5, August 29, 1925. “Shigarami and Sakae.” Japan.

(302) Pecten yamasakii Yokoyama, Jour. Fac. Sci. Imper. Univ.
Tokyo, See. II, Geol., Vol. 1, Pt. 1, p. 17, pl. 5, figs. 1, 2, 4, 5, Au-
gust 29, 1925. “Shigarami and Togakushi.” Japan.— Akiyama,

Sci. Repts. Tokyo Kyoiku Daigaku, Geol. Min. Geogr., Sec. C,
Vol. 8, No. 74, p. 95, pl. 3, fig. 3; pl. 6, fig. 3, 1962 (as Patinopecten

_(Patinopecten) yamasakii yamasakii). Early Pliocene of Japan.
(303) Kuroda, T., Fossil Moll. (in F. Homma), Shinano Chaibu

_Chishitsu-Shi (Geol. Central Shinano), Pt. 4, p. 35, pl. 2, figs. 7, 8,

1931.

353

(304) Patinopecten yamasakii ninohensis Masuda, Saito Ho-On
Kai Mus. Res. Bull., No. 23, (Geol., No. 2), p. 18, figs. 1-8, Septem-
ber, 1954. Lowermost Suenomatsuyama Formation in the Iwate
Prefecture, Japan; late Miocene.

(305) Pecten (Patinpopecten) duplex Cooks, Carnegie Inst.
Washington, Publ. 291, p. 140, pl. 11, figs. 10a, 10b, 1919. “Long
Island, Antigua, station 6869, Vaughan.” “Oligocene.” —Olsson
and Richards, Notulae Naturae Acad. Nat. Sci. Philadelphia, No.
350, p. 5, pl. 1, figs. 5, 6, 1961 (as Pecten (Flabellipecten) duplex).
Goajira Peninsula of Colombia. “Probably Upper Oligocene.”
(306) Pecten (Patinopecten) yakatagensis Clark, Bull. Geol. Soc.
Amer., Vol. 43, No. 3, p. 807, pl. 16, fig. 1, September 30, 1932.
Yakataga Reef, southeastern Alaska.

(307) Pecten oregonensis Howe var., Manning and Ogle, Calif.
State Div. Mines, Bull. 148, pl. 6, 1950.

(308) See Patinopecten (Lituyapecten) falorensis MacNeil,
U.S.G.S., Prof. Paper 354-J, p. 234, pl. 38, figs. 1 and 3, 1961. Fa-
lor Formation, Pliocene.

(309) Ogle, B.A., “Geology of Eel River Valley Area Humboldt
County, California,” Calif. State Div. Mines, Bull. 164, pp. 44-45,
1953.

(310) Patinopecten (Lituyapecten) poulcreekensis MacNeil,
U.S.G:S., Prof. Paper 354-J, p. 228, pl. 35, figs. 1-6; pl. 36, figs. 1,
2(?), 3, 4, 6, 7; pl. 38, fig. 2, 1961. Type locality, “Uppermost part
of the Poul Creek formation at Yakataga Reef, USGS loc. M-
271.” Early Miocene.

(311) See Patinopecten (Patinopecten) poculum kurosawaensis
Yokoyama, Akiyama, Sci. Repts. Tokyo Kyoiku Daigaku, Geol.,
Min. Geogr., Sec. C, Vol. 8, No. 74, p. 101, pl. 4, fig. 3, 1962. See
also remarks on pp. 112, 115.

(312) Pecten (Patinopecten) purisimaensis Arnold, U.S.G.S.,
Prof. Paper 47, p. 105, pl. 34, fig. 3; pl. 35, figs. 1, 1a, 1906. “Puris-
ima formation (lower Pliocene), north of the mouth of Pescadero
Creek, San Mateo County, Cal.” —MacNeil, U.S.G.S., Prof. Paper
354-J, p. 233, pl. 44, figs. 1, 3, 1961 [as Pecten (Lituyapecten) pu-
risimaensis }.

(313) Arnold, R., and Hannibal, H., “The Marine Tertiary
Stratigraphy of the North Pacific Coast of America,” Proc.
Amer. Philos. Soe. Vol. 52, No. 212, p. 594, 1913.

(314) Pecten coosensis Shumard, Trans. St. Louis Acad. Sci., Vol.
1, Pt. 2, p. 122, 1858. “found in great profusion at the mouth of
Coos Bay, in slightly coherent sandstone of the Miocene period.”
—Weaver, Univ. Washington Publ. Geol., Vol. 5, p. 92, pl. 18, figs.
1, 2; pl. 21, figs. 2, 5, 1942 (issued December 31, 1943) (as Pecten
(Patinopecten) coosensis). —Trumbull, Jour. Paleo., Vol. 32, No.
5, p. 901, pl. 115, figs. 1-4; pl. 116, figs. 1, 2; pl. 117, fig. 4, 1958 (as
Patinopecten coosensis). [Specimens from type lot illustrated. ]
(315) Patinopecten (Patinopecten) nakatombetsuensis Akiyama,
Sci. Repts. Tokyo Kyoiku Daigaku, See. C, Geol. Min. Geogr.,
Vol. 8, No. 74, p. 100, pl. 4, figs. 2, 5, February 5, 1962. Nakatom-
betsu Formation, early Pliocene.

(316) See Gillet, S., Mém. Soc. Géol. France, New Sér., Tom. 1,
Fasc. 3 and 4, Mém. No. 3, p. 46, 1924.

(317) See Fedotov, D. M., “Uber die Variabilitat der rezenten
Pelecypoden im Zusammengehang mit der Untersuchung fossi-
ler Formen,” Trav. Inst. Paléozool. Acad. Sci., URSS, (Lenin-
grad), Tome 2, pp. 1-16, pls. 1-3, 1933.

(318) Staesche, K., “Die Pectiniden des Schwibischen Jura,”
Geol. u. Palaeo. Abhandl., Neue Folge, Bd. 15 (Whole Ser. Ba.
19), Heft 1, pp. 1-186, pls. 1-6, figs. 1-12 in text, 1926.

(319) Dechaseaux, C., “Pectinidés Jurassiques de l’est du Bassin
de Paris,” Ann. Paléo., Tom. 25, Fase. 1-3, pp. 1-148, pls. 1-10,
March, 1936.

(320) Pecten (Chlamys) lawsoni Arnold, U.S. G. S., Prof. Paper
47, p. 117, pl. 45, figs. 3, 4, 1906.

(321) See Adegoke, O. S., Univ. Calif. Publ. Geol. Sci., Vol. 80, p.
97, 1969.

(322) Pecten (Chlamys) hastatus Sowerby, var. ingeniosa Yo-

304

koyama, Imper. Geol. Surv. Japan, Rept. 104, p. 5, pl. 6, fig. 2,
1929. ‘near Nanao.”—Masuda, Sci. Repts. Tohoku Univ., Sendai,
Japan, Second Ser. (Geol.), Vol. 33, No. 2, p. 170, pl. 22, fig. 18,
1962 (as Chlamys ingentosa).

(323) Pecten (Pecten) hastatus Sow. var. (?), Slodkewitsch,
Trans. Geol. Oil Inst., Ser. A, Fasc. 79, p. 158, pl. 12, fig. 3, 1936.
(324) See Lamy, E., Bull. Mus. Nat. Hist. Nat. (Paris), Vol. 34,
No. 2, p. 170, 1928.

(325) Pecten denticulatus Adams and Reeve, in A. Adams, Zool.
Voy. Samarang, Moll., p. 74, pl. 21, fig. 14, 1850.

(326) See Bavay, E., Jour. de Conchyl., Vol. 79, No. 4, p. 309,
1936.

(327) See Chlamys odontata Cox, Proc. Malacol. Soc. London,
Vol. 18, Pt. 5, p. 205, July 15, 1929.

(328) According to A. M. Keen (Veliger, Vol. 2, No. 4, p. 101,
April, 1960), hericius “is a noun, not an adjective, derived from
the latin word ericius, hedgehog.”

(329) Pecten (Chlamys) miyatokoensis Nomura and Hatai, Saito
Ho-On Kai Mus., Res. Bull., No. 18, p. 127, pl. 19, figs. 2-4; pl. 20,
fig. 1, August, 1987. ‘““Otutumi” and “Sabusawa,” Japan, Mio-
cene.—Masuda, Trans. Proc. Palaeo. Soc. Japan, New Ser., No.
24, p. 247-250, pl. 35, figs. 1-9b, 1956 (as Chlamys miyatokoensis).
(330) See Masuda, K., Trans. Proc. Palaeo. Soc. Japan, New
Ser., No. 22, p. 176, pl. 29, figs. 1-7, 1956. (See remarks p. 179).
(331) Pecten kaneharai Yokoyama, Jour. Fac. Sci. Imper. Univ.
Tokyo, See. 2, Vol. 1, Pt. 4, p. 185, pl. 8, fig. 1; pl. 19, figs. 1,2,5-7,
January 9, 1926. Shiobara in Shimotsuké, Japan, Pliocene. See
also, Makiyama, J., Palaeo. Soc. Japan, Spec. Papers No. 4, pl. 36,
fig. 1; pl. 37, figs. 1, 2, 5, 6, 7, 1958.

(332) See Philippi, E., Zeitschr. Deutsch. Geol. Gesell., Bd. 52,
Heft 1, figs. 9 and 10, 1900.

(333) Pecten islandicus pugetensis I. S. Oldroyd, Nautilus, Vol.
33, No. 4, p. 186, pl. 4, figs. 5 and 6, April, 1920. “off San Juan, Pu-
get Sound.”; Publ. Puget Sound Biol. Sta., Vol. 4, p. 136, pl. 4, figs.
5 and 6, 1924 (as Pecten (Chlamys) islandicus pugetensis); Stan-
ford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 55, pl. 2, figs. 4
and 5, 1924. See also MacNeil, U. 8S. G. S. Prof. Paper 553, p. 15,
pl. 22, figs. 4, 5, 1967 (as Chlamys (“Chlamys”) pugetensis). Sit-
kalidak Island, off Kodiak Island, Alaska.

(334) Gregg, W. P., Nautilus, Vol. 51, No. 4, p. 118, April, 1938.
(335) See Henderson, J., Univ. Colorado Studies, Vol. 16, No. 1,
p. 2, June, 1927.

(336) The altitude of the type specimen was given as 51 mm. in
the explanation of plate 12, figure 6, in the original publication.
This apparently was an error because Arnold in 1906 gave the al-
titude as 45 mm. and measurements of his illustration substan-
tiate this figure.

(337) See Pecten (Pecten) cf. islandicus var. jordani Arnold,
Kundert, Calif. State Div. Mines, Spec. Rept. 18, p. 15, 1952.
Whittier-LaHabra area, California, Pico Formation, Pliocene.
(338) See Chlamys islandicus jordani Arnold, Woodring, U. S.
G. S., Prof. Paper 207, p. 80, pl. 32, fig. 16, 1946. “Timms Point
silt,’’ San Pedro, California, Pleistocene.

(339) See Pecten (Chlamys) jordani Arnold, I. S. Oldroyd, Publ.
Puget Sound Biol. Sta., Vol. 4, p. 19, pl. 2, figs. 1, 2, 1924.-I. S.
Oldroyd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 55,
pl. 28, figs. 5, 6, 1924.

(340) Pecten (Chlamys) hindsvi kincaidi 1.8. Oldroyd, Publ. Pu-
get Sound Biol. Sta., Vol. 4, p. 17, pl. 9, figs. 3, 4, 1924. “Off San
Juan Island, Wash., in 25 fathoms.—Puget Sound.”—I. 8. Old-
royd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 53, pl.
12, figs. 1, 2, 1924.

(341) See Chlamys rubida jordani Arnold, Grau, Allan Hancock
Pac. Exped., Vol. 23, p. 79, pl. 25, 1959.

(342) See Pecten (Chlamys) hindsii var. jordani Arnold,
Crickmay, Canadian Field Nat., Vol. 39, No. 6, p. 140, 1925. Road
cut on Pacific highway on South side of Fraser River opposite
New Westminster, British Columbia, Pleistocene; Vol. 48, No. 9,

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

p. 206, 1929. Surrey, British Columbia, Pleistocene.

(343) Chlamys durhami Adegoke, Univ. Calif. Publ. Geol. Sci.,
Vol. 80, p. 97, pl. 2, fig. 5, September 25, 1969.

(344) See Masuda, K., Trans. Proc. Palaeo. Soc. Japan, New
Ser., No. 18, pp. 112-115, pl. 12, figs. 1-7 (Chlamys nisataiensis),
8-17 (Chlamys akitana), June 15, 1954. Early and Middle Mio-
cene.

(345) Pecten (Chlamys) hertleini Loel and Corey, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 22, No. 3, p. 195, pl. 20, figs. 4, 6,
7, 8, December 31, 1932. ‘Univ. Calif. Coll. Invert. Pal., loc. 5-15
R. N. N. Santa Ynez River Canyon, Santa Barbara County.”
Vaqueros Formation, early Miocene.

(346) Chlamys tamurae Masuda and Sawada, Jap. Jour. Geol.
Geogr., Vol. 32, No. 1, p. 27, pl. 4, figs. 12a-b, 13, 14, 15, March 20,
1961. “Small hill-side exposure at Maruyama, Kita-Hiyama-
machi, Setana-gun, Shiribeshi Province, Hokkaido (Lat.
40° 23/56’N., Long. 189°54’55’E.). Setana formation. Pliocene.”
(347) See Grant, U. S., 1V, Amer. Assoc. Petrol. Geol., Program
22nd Mtg., pp. 69-71, March 18, 1937. Also see remarks by J. W.
Valentine concerning the conditions of deposition of the strata
exposed at and near Lomita Quarry (Univ. Calif. Publ. Geol. Sci.,
Vol. 34, No. 7, pp. 411-418, 1961).

(348) See Yates, A., Santa Barbara Soc. Nat. Hist. Bull., No. 2,
p. 41, August, 1890. Santa Rosa Island, California “(Southern
limit).”

(349) Pecten (Chlamys) islandicus picoensis Waterfall, Univ.
Calif. Publ. Bull. Dept. Geol. Sci., Vol. 18, No. 3, p. 83, pl. 5, figs. 2
and 4, April 6, 1929. “Type from top of Pico, U. C. Loc. 7100, NW
corner Sec. 3, T 3N, R 21W, Ventura County, California.”

(350) Pecten (Chlamys) venturaensis Waterfall, Univ. Calif.
Publ. Bull. Dept. Geol. Sei., Vol. 18, No. 3, p. 84, pl. 6, fig. 4, April
6, 1929. “Type from top of Pico, U. C. Loe. 7097, east center of
See. 21, T 3N, R 21W, Ventura County, California.” (Cited in
table opp. p. 78 as “Pecten (Chlamys) washburnei venturaensis
n. subsp.”’)

(351) The brackets are by Carpenter.

(352) For references to this species see footnote 340.

(353) MacNeil, F. S., “Cenozoic Megafossils of Northern
Alaska,” U.S.G.S., Prof. Paper 294-C, pp. 114-115, pl. 14, fig. 1,
1957.

(354) See I. 8. Oldroyd, Amer. Malacol. Union, Seventh Ann.
Mtg. at University of Michigan, Ann Arbor, Michigan [p. 2 (not
paginated), January 1, 1938].

(355) See Chlamys islandica hindsi Carpenter, Kira, Shells of
the western Pacific in color (Hoikusha Publ. Co.: Osaka, Japan),
p. 140, pl. 50, fig. 9, 1962. In cold waters from Hokkaido to
Alaska.

(356) See Oyama, K., and Takemura, Y., The molluscan shells
(Science and Photography Club: Tokyo, Japan), II, Pecten, pl. 5,
figs. 1-3, 1958. “off Kuji.”

(357) See Kuroda, T., and Habe, T., Check List and Bibliogra-
phy of the Recent Marine Mollusca of Japan (Publ. by Leo Stach:
Tokyo, Japan), p. 16, 1952.

(358) See Dautzenberg, P., and Bavay, A., Siboga Exped.,
Monogr. 53b, Pectinidae, p. 12, 1912.

(359) Chlamys imanishii Masuda and Sawada, Jap. Jour. Geol.
Geogr., Vol. 32, No. 1, p. 25, pl. 4, figs. 10a-c, 11, March 20, 1961.
“Sea cliff at Hamada, Yokohama-mura, Kami-Kita-gun, Aomori
Prefecture (Lat. 41°08’15’N., Long. 141°16’34”E.). Hamada for-
mation. Early Pliocene.”

(360) Chlamys ingeniosa tanakai Akiyama, Trans. Proc. Paleo.
Soc. Japan, New Ser., No. 31, p. 243, pl. 36, figs. 1, 2a, 2b, 3a, 3b,
August 15, 1958. “Kawashita, Togakushi-mura, Kamiminochi-
gun. Lat. 36°40'14.5”N, Long. 1388°5’46”E.” Nagano Prefecture.
“Ogikubo sandstone and mudstone member.”

(361) See Willett, G., Bull South. Calif. Acad. Sci., Vol. 45, Pt. 1,
p. 29, 1946.

(362) See Peck, J. H., Jr., Univ. Calif. Publ. Geol. Sci., Vol. 36,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

No. 4, p. 236, (table, not paginated), 1960.

(363) See Nomland, J. O., Univ. Calif. Publ. Bull. Dept. Geol.,
Vol. 10, No. 14, p. 219, and table opp. p. 230, 1917.

(364) See Stewart, R. B., in Woodring, W. P., Stewart, R. B.,
and Richards, R. W., “Geology of the Kettleman Hills Oil Field
California,” U.S.G.S. Prof. Paper 195, p. 91, 1940 (1941).

(365) Waller, T. R., “The Evolution of the Argopecten gibbus
stock (Mollusca: Bivalvia), with Emphasis on the Tertiary and
Quaternary species of eastern North America,” Jour. Paleo., Vol.
43, Suppl. to No. 5 (Paleo. Soc., Mem. 3), pp. I-V, 1-125, pls. 1-8,
text figs. 1-13, data tables 1-43, September, 1969.

(366) See Dollfus, G. F., Mém. Soc. Géol. France, Paléo., Vol. 18,
Fasc. 3-4, (Mém. No. 44), p. 62, pl. 4, figs. 34, 35, 1911.

(367) Pecten (Plagioctenium) neahensis Arnold, U.S.G:S., Prof.
Paper 47, p. 87, pl. 15, figs. 2, 2a, 2b, 1906. “Miocene, Strait of
Fuca, east of Neah Bay, Clallam County, Wash.” See also
Weaver, [1942 (1943), p. 90] concerning the occurrence of this
species.

(368) Pecten (Plagioctenium) abietis E. K. Jordan and L. G.
Hertlein, Proc. Calif. Acad. Sci., Fourth Ser., Vol. 15, No. 4, p.
214, pl. 23, figs. 1, 3, 7, April 26, 1926. “Arroyo Hondo, Maria
Madre Island, Mexico; upper Pliocene.”—Durham, Geol. Soc.
Amer., Mem. 48, Pt. 2, p. 62, pl. 10, figs. 4, 7; pl. 11, fig. 4, 1950 (as
Aequipecten abietis). -Emerson and Hertlein, Trans. San Diego
Soc. Nat. Hist., Vol. 13, No. 17, p. 354, figs. 4a-c, 1964 (as Chlamys
(Argopecten) abietis). (With synon.)

(369) For reference concerning C. (A.) circularis aequisulcata,
see footnote 370.

(370) Pecten aequisulcatus, ?n.s., Carpenter, Rept. Brit. Assoc.
Adv. Sci. for 1863, p. 645, August, 1864. Reprint in Smithsonian
Miscell. Coll., No. 252, p. 1381, 1872. Indicated as from neighbor-
hood of Santa Barbara and the region between San Diego and
San Pedro, California. See also, Carpenter, 1864, pp. 536, 540,
592, 599; reprint, 1872, pp. 22, 26, 78, 85. San Diego and San
Pedro, California. —Arnold, U.S.G.S., Prof. Paper 47, p. 182, pl.
50, figs. 1, la, 1b; text fig. 1, p. 45, fig. 2, p. 46, 1906 (as Pecten
(Plagioctenium) circularis Sowerby var. aequisulcatus). Pleisto-
cene and Recent.—K. V. W. Palmer, Geol. Soc. Amer., Mem. 76, p.
71, pl. 3, figs. 1-8, 1958 (as Pecten (Plagiocteniwm) circularis
aequisulcatus). “Recent. San Diego, California (type).” Also
other localities.

(371) Ostrea gibba Linnaeus, Syst. Nat., ed. 10, p. 698, 1758. Ref.
to “Brown, jam. t. 40, f. 10.” “Habitat in M. Americano.”—Reeve,
Conch. Icon., Vol. 8, Pecten, sp. 37, pl. 9, figs. 37b, 37c, 1852 (as
Pecten gibbus). For a discussion of this species see Tucker-Row-
land (1938, pp. 44-46, pl. 4, fig. 21); Dodge, Bull. Amer. Mus. Nat.
Hist., Vol. 100, Art. 1, pp. 182-183, 1952; Waller, 1969, pp. 36-38,
pl. 8, figs. 1-4, 1969.

(372) Davenport, C. B., “Comparison of some pectens from the
east and the west coasts of the United States.” Mark Anniver-
sary Volume, Art. 6, pp. 121-136, pl. 9, 1903.

(373) See Weisbord, N. E., Bull. Amer. Paleo., Vol. 45, No. 204,
pp. 150-152, 1964.

(374) Pecten (Plagioctenium) calli Hertlein, Proc. Calif. Acad.
Sci. Ser. 4, Vol. 14, No. 1, p. 16, pl. 4, figs. 5, 6, 7, July 21, 1925.
“first arroyo east of Santiago, Lower California.” “Miocene?”
[Pliocene]._E. K. Jordan and Hertlein, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 15, No. 14, p. 436, pl. 27, fig. 5, 1926. ‘Pliocene beds ex-
posed about a prominent monadnock, from one to two miles to
southeast of Turtle Bay. Upper Pliocene.” Also other localities.
(375) Durham, J. W., Geol. Soc. Amer., Mem. 43, Pt. 2, p. 63,
1950.

(376) Aequipecten circularis subsp. bramkampi Durham, Geol.
Soc. Amer., Mem. 43, Pt. 2, p. 63, pl. 9, figs. 2, 4, 8, August 10,
1950. From Loc. A1268 (U.C.) Imperial Formation, northwest
side of Carrizo Mountain, Imperial Co., California. Pliocene.
(377) Pecten (Plagioctenium) eldridgei Arnold, U.S.G.S., Prof.
Paper 47, p. 87, pl. 25, figs. 3, 3a, 3b, 4, 4a, 5, 5a, 6, 1906. “San

395

Pablo formation (upper Miocene), McKittrick district, Kern
County, Cal.”[Pliocene.]—Woodring and Stewart, U.S.G.S., Prof.
Paper 195, p. 91, pl. 24, figs. 10-13, 1940 (1941) (as Aequipecten
circularis eldridgei). Kettleman Hills, California; San Joaquin
Formation, late Pliocene.

(378) Pecten deserti Conrad, House Document 129, Projected
Vol. 3, 33rd Congress, Ist session, July, 1855, p. 15. “Locality.—
Carrizo creek, Colorado desert. Miocene.” [On page 5, Conrad
mentioned “Pecten vespertinus” “occurring in the bank of Car-
rizo creek.” No description ever appeared and presumably this
form was named Pecten deserti.]|—Conrad, Pac. Railroad Expl.,
Vol. 5, p. 325, pl. 5, fig. 41, 1857.

(379) Pecten (Plagioctenium) deserti Conrad, Arnold, U.S.G:S.,
Prof. Paper 47, p. 85, pl. 26, figs. 1, 2, 2a, 3, 4, 4a, 1906.—See also
Nomland, Univ. Calif. Publ., Bull. Dept. Geol., Vol. 10, No. 14, p.
282 (in text), pl. 6, figs. 1, la, 1b, 1917; Hanna, Proce. Calif. Acad.
Sci., Ser. 4, Vol. 14, No. 18, p. 470, pl. 25, figs. 1, 2, 3, 1926; Mans-
field, U.S.G.S., Prof. Paper 170-D, pl. 17, figs. 3, 6, 1932.

(380) Pecten circularis cornellanus F. and H. Hodson, Bull.
Amer. Paleo., Vol. 18, No. 49, p. 26, pl. 14, fig. 2; pl. 15, figs. 3, 10;
pl. 16, fig. 3, October 7, 1927, Venezuela, “Age: Miocene.”

(381) Pecten circularis venezuelanus F. and H. Hodson, Bull.
Amer. Paleo., Vol. 18, No. 49, p. 25, pl. 14, fig. 6; pl. 15, figs. 2, 4, 5;
pl. 17, fig. 1, October 7, 1927. Venezuela. “Age: Miocene and
Pliocene.”

(382) Pecten circularis caucanus F. and H. Hodson, Bull. Amer.
Paleo., Vol. 18, No. 49, p. 27, pl. 15, figs. 1, 8, October 7, 1927.
“District of Democracia, State of Falcén,’ Venezuela. “Age:
Pliocene.”

(383) Pecten (Plagioctenium) demiurgus Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, Pt. 4, p. 718, pl. 26, fig. 3, April, 1898.
“From the Caroni Series of Trinidad at Savanetta; Guppy.”
(384) Vokes, H. E., in Wilson, I. F., Bull. Amer. Assoc. Petrol.
Geol., Vol. 82, No. 9, pp. 1782, 1783, 1948. Also Vokes, in Wilson, I.
F., and Rocha, V. F., U.S.G.S., Prof. Paper 273, pp. 36, 39, 1955.
(385) Pecten (Plagioctenium) cristobalensis Hertlein, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 14, No. 1, p. 19, pl. 3, figs. 1, 2, 5, July 21,
1925. “Slopes of Salada three miles southeast of Turtle Bay, up-
permost beds, San Cristobal Bay Quadrangle, Lower Califor-
nia.” “Salada, Pliocene.”

(386) Pecten purpuratus Lamarck, Hist. Nat. Anim. s. Vert.,
Vol. 6, p. 166, 1819. ““Habite les mers orientales et austra-
les.”[Western South America.]—Delessert, Recueil Coquilles,
décrites par Lamarck et non encore figurées, pl. 16, figs. 5a, 5b,
5e, 1841.—Reeve, Conch. Icon., Vol. 8, Pecten, sp. 25, pl. 5, fig. 25,
1852. “Bay of Callao, Peru.’’—Kiister, Martini u. Chemnitz Con-
chyl. -Cab., Bd. 7, Abt. 2, p. 78, taf. 20, figs. 1-3, 1888. “Kiisten
von Peru und Chili.”

(387) See Woodring, W. P., in Hoots, H., U.S.G.S., Prof. Paper
165, p. 119, 1931.

(388) See Oakshott, G. B., California State Div. Mines, Bull. 172,
p. 80, 1958 (identification by W. E. Ford).

(389) See Winterer, E. L., and Durham, D. L., U.S.G.S., Prof.
Paper 334-H, p. 302, 1962 (as “cf. Aequipecten purpuratus.”
Identification by W. P. Woodring, J. G. Vedder, and Ellen J.
Trumbull).

(390) See Vokes, H. E., in Wilson, I. F., Bull. Amer. Assoc. Pet-
rol. Geol., Vol. 32, No. 9, pp. 1788, 1784, 1948.

(391) Aequipecten antonitaensis Durham, Geol. Soc. Amer.,
Mem. 48, Pt. 2, p. 62, pl. 9, figs. 1,5, August 10, 1950.

(392) Chlamys (Argopecten) coopericellus Ferreira, Arquivos do
Mus. Nacional, (Rio de Janeiro), Vol. 50, p. 150, pl. 2, fig. 4, De-
cember 31, 1960. Pirabas Formation, early Miocene.

(393) Pecten cooperi |Arnold], Kryshtofovich, The Pacific, Rus-
sian Scientific Investigations, Acad. Sci. USSR., (Leningrad),
1926, opp. p. 80.

(394) Pecten impostor Hanna, Proce. Calif. Acad. Sci., Ser. 4, Vol.
13, No. 10, p. 177, March 18, 1924. New name for Pecten proteus

356

Nomland, Univ. Calif. Publ. Bull. Dept. Geol., Vol. 10, No. 14, p.
232, pl. 6, figs. 2, 2a, 2b, 2c, April 9, 1917. Type from Loc. 2991
(UC), “Near center of SE % Sec. 17, T. 22 S, R. 16 E. on top of
ridge south of road. Pecten coalingensis zone” (p. 230). Not Pec-
ten proteus Sowerby, 1847.

(395) For references to this species see footnotes 378 and 379.
(396) See Aequipecten circularis impostor Hanna, Woodring
and Stewart, U.S.G.S., Prof. Paper 195, p. 91, pl. 13, figs. 3, 4,
1940 (June 7, 1941). Pecten zone, Kettleman Hills, California. San
Joaquin Formation, late Pliocene.

(397) Pecten eboreus var. senescens Dall, Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 4, p. 751, pl. 29, fig. 5, April, 1898. “Pliocene
of the Waccamaw beds, South Carolina; Johnson.”—Tucker-Row-
land, Mém. Mus. Roy. Hist. Nat. Belgique, Deuxiéme Sér., Fasc.
13, p. 50, pl. 4, fig. 15, 1938 (as Chlamys (Plagiocteniwm) eboreus
senescens Dall).

(398) Chlamys eboreus walkerensis Tucker, Amer. Midland
Nat., Vol. 15, No. 5, p. 616, pl. 27, fig. 3, 1934. “Waccamaw Plio-
cene. Walkers, N. C. (type).”

(399) Chlamys (Argopecten) imitata Weisbord, Bull. Amer.
Paleo., Vol. 45, No. 204, p. 152, pl. 26, figs. 5-10, February 18, 1964.
Playa Grande Formation (Catia Member).

(400) Vokes, H. E., in Wilson, I. F., Bull. Amer. Assoc. Petrol.
Geol., Vol. 32, No. 9, pp. 1782, 1783, 1948.—Vokes, H. E., in Wil-
son, I. F., and Rocha, V. L., U.S.G.S., Prof. Paper 273, pp. 36, 39,
1955.

(401) Pecten (Leptopecten) praevalidus EB. K. Jordan and Hert-
lein, Proc. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 435, pl. 29,
figs. 2 and 3, July 22, 1926. “Southeast of Turtle Bay, Lower Cali-
fornia; upper Pliocene.”

(402) Chlamys (Antipecten) sacyi Cossmann and Peyrot, Act.
Soc. Linn. de Bordeaux, Vol. 68, (Conch. Néogéne de
L’Aquitaine, Vol. 2, Livr. 2), p. 338, pl. 15, figs. 12, 13, 15-19, Au-
gust, 1914. “Cestas (pré Cazeaux).” See also Roger, 1939, p. 65,
pl. 2, fig. 8; pl. 3, figs. 6, 6a.

(403) Cossmann, M., in Cossmann and Peyrot, 1914, p. 313. “(G.-
T.: Chl. Sacyi nov. sp. Mioc.)”

(404) Pecten (Chlamys) latiawritus Conrad var. delosi Arnold,
U.S.G.S., Prof. Paper 47, p. 130, pl. 46, figs. 9, 9a, 10, 10a, 1906.
“San Pedro formation (lower portion), Pleistocene, Deadman Is-
land, near San Pedro, Los Angeles County, Cal.”

(405) See Webb, R. W., Trans. San Diego Soc. Nat. Hist., Vol. 8,
No. 24, p. 345, 1937.

(406) Chlamys (Leptopecten) desultoria Weisbord, Bull. Amer.
Paleo., Vol. 45, No. 204, p. 145, pl. 15, figs. 3-6, February 18, 1964.
(407) Woodring, W. P., “Lower Pliocene Mollusks and Echinoids
from the Los Angeles Basin, California.” U.S.G.S., Prof. Paper
190, p. 6, 1938.

(408) See Arnold, R., in Branner, J. C., Newsome, J. F., and Ar-
nold, R., U.S.G.S., Folio 163, p. 6, 1909.

(409) Jordan, E. K., and Hertlein, L. G., “Contributions to the
Geology and Paleontology of the Tertiary of Cedros Island and
Adjacent Parts of Lower California,” Proc. Calif. Acad. Sci., Ser.
4, Vol. 15, No. 14, p. 418, 1926.

(410) Aequipecten (Leptopecten) camerella Berry, Leaflets in
Malacol., Vol. 1, No. 25, p. 155, September 26, 1968. “'Type-Local-
ity: 35-40 fms., region of La Ribera, Baja California Sur”... .
(411) See Chlamys (Leptopecten) cf. latiawrata (Conrad, 1837),
Ferreira, Arquivos do Mus. Nacional (Rio de Janeiro), Vol. 50, p.
152, pl. 4, fig. 3, December 31, 1960. “Mioceno inferior: Formacao
Pirabas.”

(412) Aequipecten (Leptopecten) cracens Olsson, Neogene Mol-
lusks from Northwestern Ecuador (Paleo. Res. Inst.: Ithaca,
New York), p. 36, pl. 3, figs. 7, 7a, October 28, 1964. Angostura
Formation, 'Telembi, Rio Cayapas.”

(413) Coe, W. R., “Season of Attachment and Rate of Growth of
Sedentary Marine Organisms at the Pier of the Scripps In-
stitution of Oceanography, La Jolla, California,” Bull. Scripps

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Inst. Oceanogr. Univ. Calif., Tech. Ser., Vol. 3, No. 3, pp. 37-86,
pls. 1-6, figs. 1-3 in text, March 4, 1932. [See especially pp. 60-61,
pls. 4-5.] See also Coe, W. R., “Development of the Reproductive
System and variations in Sexuality in Pecten and other Pelecy-
pod Mollusks,” Trans. Connecticut Acad. Arts Sci., Vol. 36, pp.
673-700, figs. 1-8 in text, July 1945. [See especially pp. 680-681,
figs. 1, 2.]

(414) Williams, Woodbridge, pers. comm. September 2, 1947.
(415) See Futterer, K., Palaeo. Abhandl., Neue Folge, Bd. 2,
Heft 1, p. 79, 1892.

(416) Pecten (Chlamys) hamlini Arnold, U.S.G.S., Prof. Paper
47, p. 67, pl. 11, fig. 2, 1906. “Miocene (lower?), head of Slacks
Canyon, Monterey County, Cal.”

(417) Pecten praevasseli de Bockh and Richardson, in Douglas,
Contributions to Persian Palaeontology, III, p. 6, pl. 10, figs. 3, 4,
September, 1928. (P. 18) ‘Middle Miocene limestone, near Cham-
peh, Persia.” See also Eames and Cox, Proc. Malacol. Soc. Lon-
don, Vol. 32, pts. 1 & 2, p. 35, pl. 14, figs. 1, 2, 1956.

(418) Pecten natoriensis Matsumoto, Sci. Rept. Tohoku Imper.
Univ. Sendai, Japan, Ser. 2, (Geol.), Vol. 13, No. 3, p. 104, pl. 40,
figs. 10, 11, 1930. Natori district, Japan, “Upper Miocene.”

(419) Hatai, K. M., and Nisiyama, S., Saito Ho-On Kai Mus.,
Res. Bull. No. 6, pp. 100-102, 1935.

(420) Hatai, K. M., and Nisiyama, S., Trans. Proc. Palaeo, Soc.
Japan, No. 14, p. 48 (9), 1989 (Reprinted from Jour. Geol. Soc. Ja-
pan, Vol. 46, No. 544).

(421) Nanaochlamys Hatai and Masuda, Trans. Proc. Palaeont.
Soc. Japan, New Ser., No. 11, p. 76, September 30, 1953. ‘“Gen-
otype:-Pecten notoensis Yokoyama, 1929.” Described and illus-
trated p. 77, pl. 7, figs. 1-7 and text figs. 2, 3. “Type locality:—
Calcareous sandstone of the Miocene Nanao formation at Iwaya,
Nanao City, Ishikawa Prefecture.” “Geological range:—Early
Miocene.” See also Masuda, K., “On the morphogenesis of Na-
naochlamys,” Sei Repts. Tohoku Univ., Sendai, Japan, 2nd Ser.
(Geol.), Spec. Vol. No. 4, pp. 371-383, pl. 39, figs. 1-10 in text,
March, 1959.

(422) Decatopecten Riippel in Sowerby, Conch. Manual, p. 37,
1839. Sole species, “Pecten Plica, Linn. Fig. 172.” In later edi-
tions as Decadopecten. According to Sherborn, the original spell-
ing is “err. typ. pro Decado-.” See also Treatise on Invert. Paleo.,
Part N, Vol. 1, p. N365, 1969.

(423) Anguipecten Dall, Bartsch, and Rehder, Bernice P. Bishop
Mus., Bull. 153, p. 92, July 25, 1938. “Type: Anguipecten gregory,
new species,” p. 93, pl. 23, figs. 5, 6, 8. Recent, Hawaii.

(424) Manupecten Monterosato, Jour. de Conchyl., Vol. 37, (Ser.
38, Vol. 29), No. 1, p. 21, issued May 2, 1889.—Sacco, Moll. Terr.
Terz. Piemonte e Liguria, Pt. 24, p. 36, December, 1897. “(tipo M.
pesfelis (L.)).””

(425) Felipes Loc., Carus, Faunae Mediterr., Vol. 2, Pt. 1, p. 71,
1889-1893 (issued December, 1889). [Concerning dates of pub-
lication of Felipes, see Tucker-Rowland, H. I., Bull. Mus. Roy.
d’Hist. Nat. Belgique, Tom. 14, No. 49, p. 8, August, 1938.]—Dall,
Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p. 696, 1898. Felipes
“with P. pesfelis as the type.” [Pelipes error pro Felipes Carus,
Haas, Klassen and Ordnung des Tierreichs, 2.2, p. 292, 1938.]
(426) Semipallium Jousseaume in Lamy, Bull. Mus. Nat. Hist.
Nat. Paris, Ser. 1, Vol. 34, No. 2, p. 169, 1928. Type (by mon-
otypy): Pecten tigris Lamarck. Illustrated by Chenu, Illustr.
Conchyl., Pts. 29, 30, p. 7, pl. 27, figs. 3, 3a, 4, 4a, 1844.—Chenu,
Man. de Conchyl., Vol. 2, p. 188, fig. 924, 1862.

(427) Mesopeplum Iredale, Rec. Australian Mus., Vol. 17, No. 4,
pp. 162, 188, September 4, 1929. “Type Mesopeplum caroli Ire-
dale,” p. 162, pl. 38, figs. 7, 8, 9. “Trawled in 40-80 fathoms off the
New South Wales coast.”

(428) Notochlamys Cotton, Rec. South Australian Mus., Vol. 4,
No. 2, p. 238, July 18, 1930. Type (by original designation):
Chlamys anguineus Finlay = P. undulatus Sowerby. [This
supraspecific unit is very similar to Mesopeplum. It was de

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

scribed as differing in possessing fine shagreen sculpture and in
lacking concentric threads. |

(429) Anatipopecten Hertlein, Nautilus, Vol. 50, No. 1, p. 26,
July 1936. “with Pecten anatipes Morton as type.” Illustrated by
Rowland, Amer. Midland Nat., Vol. 17, No. 6, p. 1004, pl. 7, fig. 2;
pl. 10, fig. 18, November, 1936. Vicksburg, Oligocene.

(430) Stralopecten Rowland, Jour. Conch., Vol. 21, No. 5, p. 81,
September 22, 1938. Type (by original designation): Stralopecten
ernestsmithi Tucker, illustrated in Mém. Mus. Roy. Hist. Nat.
Belgique, Deuxiéme Sér., Fasc. 13, p. 27, pl. 2, fig. 7, 1938. Origi-
nally described in Proc. Indiana Acad. Sci., Vol. 40, pp. 244, 245,
pl. 1, figs. 3, 4, 1931. North Carolina, Pliocene.

(431) Pecten etchegoini F. M. Anderson, Proc. Calif. Acad. Sci.,
Ser. 3, Vol. 2, No. 2, p. 198, pl. 18, figs. 92, 98, December 4, 1905.
“Etchegoin Beds of the Kreyenhagen ranch on Zapata Chino
Creek.” —Stewart, in Woodring, Stewart, and Richards, U.S.G.S.,
Prof. Paper 195, p. 91, pl. 18, fig. 5; pl. 32, fig. 1, 1940 (1941) (as
Chlamys etchegoini).

(432) Pecten (Chlamys) hamlini Arnold, U.S.G.S., Prof. Paper
47, p. 67, pl. 11, fig. 2, 1906. “Miocene (lower?), head of Slacks
Canyon, Monterey County, Cal.”

(433) Pecten (Chlamys) nutteri Arnold, U.S.G.S., Prof. Paper
47, p. 67, pl. 11, figs, 3, 4, 4a, 1906. “Purisima formation (lower
Pliocene), south of mouth of San Gregorio Creek, San Mateo
County, Cal.” (Type.)

(434) Pecten (Chlamys) wattsi Arnold, U.S.G.S., Prof. Paper 47,
p. 120, pl. 11, figs. 1, la, 1906. “The type is from Kreyenhagen’s
Ranch, Fresno County.” [A lectotype, No. 5945, is in the series of
type specimens in the department of Geology, California Acad-
emy of Sciences. See Hanna, G D., and Hertlein, L. G., Calif.
State Div. Mines, Bull. 118, Pt. 2, p. 176, pre-print August, 1941,
made available September 11, 1941.]

(435) Pecten (Chlamys) wattsi var. morani Arnold, U.S.G.S.,
Prof. Paper 47, p. 121, pl. 10, figs. 3, 4, 5, 6, 1906. “Pliocene
(lower). T. H. Moran’s place, SW. \% sec. 14, T. 20S., R. 12 E.,
Mount Diablo Meridian, Priest Valley, Monterey County (Ham-
lin and Arnold).””

Reagan (Trans. Kansas Acad. Sci., Vol. 22, pp. 172, 198, 1909)
reported the occurrence of “Pecten (Chlamys) wattsi var. mo-
rani Arnold?” from beds exposed at East Clallam, western
Washington. We have not seen specimens from that area.

(436) Pecten (Chlamys) kindlei Dall, U.S.G.S., Prof. Paper 125-
C, p. 30, pl. 6, figs. 2, 7, 1920. ‘Pliocene of Center Creek Mines, 2
miles north of Nome, from the second beach.”’ Alaska.—MacNeil,
Jour. Paleo., Vol. 17, No. 1, p. 87, pl. 12, figs. 7, 8, 1943 (as Pecten
(Manupecten) kindlei). Intermediate Beach, near Nome, Alaska,
Pliocene. ?Second Beach, fragment.

(437) Chlamys (Swiftopecten) donmilleri MacNeil, U.S.G.S.,
Prof. Paper 553, p. 12, pl. 3, figs. 1, 4, 6, 1967. “Type locality: 1,500
ft above base of Yakataga Formation (horizon probably middle
Miocene), south side of White River near foot of glacier, Yaka-
taga district, Alaska, USGS 6694.”

(438) See Arnold, R., U.S.G.S., Bull. 396, p. 77, 1909 (issued Jan-
uary 15, 1910.)

(439) See-Nomland, J. O., Univ. Calif. Publ. Geol., Vol. 10, No.
14, p. 289, pl. 7, figs. 1-5; pl. 8, figs. 2, 2a, 2b, April 19, 1917.

(440) Clark, B. L., in Santillan, M., and Barrera, T., Ann. Inst.
Geol., Vol. 5, p. 25, 1930. “en las terrazas al E. de San Quintin y
entre Colnett y San Isidro.” Pliocene.

(441) See Hertlein, L. G., and Allison, E. C., Bull. South. Calif.
Acad. Sci., Vol. 58, Pt. 1, p. 21, 1959.

(442) Pecten (Pallium) swiftii Bernardi var etchegoini Ander-
‘son, Slodkewitsch, Paleo. USSR. Tertiary Pelecypoda from the
Far East (Acad. Sci., USSR.) Vol. 10, Pt. 3, Fase. 18, p. 179, 1938;
also Fasc. 19, p. 109, pl. 28, figs. 1, 2, 2a, 3, 3a, 4, 5a; pl. 29, fig. 5,
1938.

(443) See Cummings, J. C., Touring, R. M., and Brabb, E. E.,
Calif. Div. Mines and Geol., Bull. 181, p. 200, photo 15, No. 2,

357

1962. Tahana member of the Purisima Formation, Pliocene.
(444) Smith, J. P., Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, p.
161, 1919.

(445) Pecten (Lyropecten) hopkinsi Olsson, Bull. Amer. Paleo.,
Vol. 19, Bull. No. 68, p. 83, pl. 5, figs. 1, 4, June 30, 1932. ““Tumbez
formation, Que. Tucillal at Zorritos.’”’ Peru, Miocene.

(446) Hass, O., Jour. Paleo., Vol. 16, No. 3, p. 309, May, 1942.
(447) See Dollfus, G. F., Jour. de Conchyl., Vol. 56, No. 1, pp. 64-
66, August 25, 1908.

(448) Clark, B. L., and Durham, J. W., in Schenck, H. G., and
Childs, T. S., Jr., Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 3,
No. 2, pp. 61 (37)-62 (38), 1942.

(449) North, K. F., (pers. comm.).

(450) Macrochlamis Sacco, Bol. Mus. Zool. e Comp. Anat. (To-
rino), Vol. 12, No. 298, p. 101, June, 1897. “Macrochlamis latis-
sima (Br.) (tipo del nuovo sottog.).” Sacco changed the spelling
to Macrochlamys in Moll. Terr. Terz. Piemonte e Liguria, Pt. 24,
p. 32, December, 1897. Not Macrochlamys Benson, 1832. Accord-
ing to the present rules of the Internatl. Comm. Zool. Nomencl.,
the earlier spelling by Sacco can be considered valid. Thus nei-
ther of the appropriate names Gigantopecten nor Grandipecten
is available for this taxon.

(451) Pecten antiguensis churuguarensis F. and H. Hodson
(Bull. Amer. Paleo., Vol. 13, No. 49, p. 35, pl. 20, figs. 1, 3, 4; pl. 22,
fig. 2, October 7, 1927) described from beds said to be of ‘‘Oligo-
cene” age in Venezuela, is a typical Amussiopecten. It bears a
resemblance to some varieties of Pecten burdigalensis Lamarck,
the type of Amussiopecten. See for example, Amussiopecten
burdigalensis var. spinosella Sacco Moll. Terr. Terz. Liguria e
Piemonte, Pt. 24, p. 53, pl. 15, fig. 9, December, 1897. “Vignale,”
Italy, Helvetian, Miocene.

(452) Nodipecten Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt.
4, p. 695, April, 1898. “Type P. nodosus L.”

(453) Roger, J., Mém. Soc. Géol. France, New Ser., Vol. 17, Fase.
2-4, Feuilles 7-48, Mém. No. 40 (completion of Mém. de Paléo. No.
26), pp. 44, 46, 1939.

(454) See Eames, F. E., and Cox, L. R., Proc. Malacol. Soc. Lon-
don, Vol. 32, Pts. 1 and 2, p. 59, 1956.

(455) See Grant, U. S., and Gale, H. R., Mem. San Diego Soc.
Nat. Hist., Vol. 1, pl. 9, fig. 1; pl. 10, fig. 6, 1931.

(456) Live specimens of Pecten subnodosus were reported re-
cently from off Santa Catalina Island, California, by Turner and
Mitchell (Calif. Fish and Game, Vol. 54, No. 1, p. 53, fig. 3, Janu-
ary, 1968).

(457) Athlopecten Marwick, Trans. Proc. New Zealand Inst.,
Vol. 58, Pt. 4, pp. 447, 454, February 28, 1927. “Type: Pecten ath-
leta Zittel” [Palaont. von Neu-Seeland, Novara Exped., Geol.
Theil., Bd. 1, Abt. 2, p. 49, Taf. 10, fig. 1, 1864.] “Motupipi in der
Massacre-Bay, Siidinsel.”

(458) Pecten simpsoni Philippi, Los Fésiles Terciarios i Cuar-
tarios de Chile (Santiago), p. 202, pl. 46, fig. 1, 1887. “Comun en
Chiloé.”” Also ‘‘Humfiimo”; and “La Mocha, Navidad (raro), Cu-
rauma.”

(459) See Boreham, A. U. E., “The New Zealand Tertiary genus
Sectipecten Marwick (Mollusca),” Trans. Roy. Soc. New Zealand,
Vol. 88. (quart. issue), Pt. 4, pp. 655-668, pls. 45-49, fig. 1 in text,
February, 1961.

(460) Reported recently by Addicott (U.S.G.S., Prof. Paper 524-
A, p. A-18, pl. 3, Fig. 8, 1965) from the Pancho Rico Formation,
Salinas Valley, California, Pliocene.

(461) Palliwm estrellanum Conrad, Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 8, No. 6, p. 318, December, 1856 (apparently issued
early in 1857) “Locality. Estrella valley, Cal. Dr. Newberry.”—
Arnold, U.S.G.S., Prof. Paper 47, p. 74, pl. 19, figs. 1, la; pl. 20,
figs. 1, 2, 2a; pl. 21, figs. 1, la, 1b, 2, 2a, 2b, 1906 (as Pecten (Ly-
ropecten) estrellanus). Late Miocene.

(462) Pecten (Lyropecten) estrellanus Conrad var. terminus
Conrad, Arnold, U.S.G.S., Prof. Paper 47, p. 77, pl. 28, figs. 2, 2a,

358

1906. “Santa Margarita formation (upper Miocene), Monterey
County, Cal.” (expl. to plate). Woodring (U.S.G.S., Prof. Paper
190, p. 34, 1938) suggested that the specimen illustrated by Ar-
nold on pl. 19, figs. 1, la, is probably referable to P. e. terminus.
(463) Pecten (Lyropecten) estrellanus Conrad var. catalinae Ar-
nold, U.S.G.S., Prof. Paper 47, p. 76, pl. 20, figs. 3, 3a, 4, 1906.
“found in a limy matrix near Isthmus, Santa Catalina Island,
Los Angeles County.” “Upper Miocene.”

(464) Pecten (Lyropecten) gallegosi E. K. Jordan and Hertlein,
Proce. Calif. Acad. Sci., Ser. 4, Vol. 15, No. 14, p. 434, pl. 29, fig. 1,
July 22, 1926. “on shore nine miles north of Bernstein’s abalone
camp, Cedros Island, Lower California; upper Pliocene.”

(465) Pallium crassicardo Conrad, Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 8, No. 6, p. 318, December, 1856 (apparently issued
early in 1857). “Locality. Monterey Co., Cal. A. S. Taylor.”—Ar-
nold, U.S.G.S., Prof. Paper 47, p. 71, pl. 16, figs. 1, 1a; pl. 17, figs.
1, la, 1b; pl. 18, figs. 1, 2, 2a, 1906. Late Miocene also in early Mio-
cene in southern California.

(466) Fischer, M. P., “Sur l’Anatomie des Hinnites,” Jour. de
Conchyl., Vol. 10, No. 3 (Ser. 3, Vol. 2), pp. 205-217, pl. 11, 1862.
See also Vol. 11, pp. 144-146, 1863.

(467) See Dall, W. H., Bull. U.S. Nat. Mus., Vol. 90, p. 134, 1915.
(468) Prohinnites Gillet, Bull. Soc. Hist. Nat. L’yonne, Vol. 75,
(II, Sei. Nat.), p. 94, Ann. 1921 (1922). Type designated by Korob-
kov (in Osnovy Paleontologii. Spravochnik dlia Paleontologov i
Geologov SSSR. Molliuski-Pantzirnye, Dvustvorchatye, Lopato-
nogie. Otvetstvennyi redaktor toma A. G. Eberzin. Izdatel’stvo
Akademii Nauk SSSR, Moskva, p. 84, 1960). Type, Hinnites
leymerieri Deshayes, 1842.

(469) See Rollier, L., Abhandl. Schweiz. Paldo. Gesellsch., Bd. 41,
pp. 450-466, 1915.

(470) Hinnites crassa Conrad, U.S. Pac. Railroad Survey Expl.,
Vol. 7, Pt. 2, p. 190, pl. 2, figs. 1, 2, 1856 (1857). “Locality.-Santa
Margarita, Salinas Valley.”

(471) Pecten (Chlamys) multirugosus var. crassiplicatus Gale,
Trans. San Diego Soe. Nat. Hist., Vol. 5, No. 9, p. 93, February
29, 1928.

(472) Arnold, R., U.S.G.S., Prof. Paper 47, p. 94, pl. 29, fig. 1,
1906. (Figure of Conrad’s type of Hinnites crassa).

(473) Woodring, W. P., and Stewart, R. B., in Woodring, W. P.,
Stewart, R. B., and Richards, R. W., U.S.GS., Prof. Paper 195, p.
70, and list opp. p. 78, pl. 31, figs. 3, 4, 8, 1940 (1941).

(474) Hinnites benedicti Adegoke, Univ. Calif. Publ. Geol. Sci.,
Vol. 80, p. 108, pl. 3, figs. 3, 5, September 25, 1969.

(475) Dollfus, G. F., and Dautzenberg, P., Mém. Soc. Géol.
France, Paléo., Mém. No. 27, (Vol. 22, Fase. 2-4), p. 436, 1920.
(476) Yonge, C. M., Studies on Pacific Coast Mollusks. III. Ob-
servations on Hinnites multirugosus Gale. Univ. Calif. Publ.
Zool., Vol. 55, No. 8, pp. 409-420, figs. 1-6 in text, November 16,
1951.

(477) Eyerdam, W. J., Nautilus, Vol. 47, No. 1, p. 36, 1933.

(478) See Bryan, W. A., Natural History of Hawaii, pp. 445, 457,
pl. 104, fig. 18, 1915.

(479) See Henderson, J., Nautilus, Vol. 40, No. 3, p. 81, 1927.
(480) See Wood, S. V., Palaeontogr. Soc. London, Vol. 27, Sup-
plement to the Monograph of the Crag Mollusea, Part II, Bi-
valves, p. 102, for 1873, (issued 1874).

(481) Propeamussium de Gregorio, Nat. Siciliano, Anno 3, No. 4,
p. 119, January 1, 1894. Sole species, Pecten (Propeamussium) ce-
ciliae de Gregorio. Sicily, Miocene. See also de Gregorio, Ann. de
Géol. et Paléo., Livr. 23, pp. 5, 19, pl. 4, figs. 10-14, 1898.

(482) Chlamydella Iredale, Rec. Australian Mus., Vol. 17, No. 4,
pp. 164, 188, September 4, 1929. "type: Cyclopecten favus Hed-
ley,’ Australian Museum, Mem. 4, Vol. 1, Pt. 5, p. 305, fig. 50,
July 29, 1902. “Off Port Kembla in 63-75 fathoms, and off Cape
Three Points in 41-50 fathoms,” Australia.

(483) See Barnard, K. H., Ann. South African Mus., Vol. 47, Pt.
3, pp. 421, 488, March, 1964.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(484) This species was reported from a depth of 860 fathoms by
Durham (Nautilus, Vol. 55, No. 4, p. 121, 1942) and from 1720
fathoms by Emerson and Puffer (Amer. Mus. Novitates, No.
1825, p. 18, 1957). Grau (1959, p. 34) stated concerning such speci-
mens, “it is almost certain that they were not living at that
great depth.”

(485) Pecten (Cyclopecten) cocosensis Dall, Bull. Mus. Comp.
Zool., Harvard Coll., Vol. 48, No. 6, p. 405, pl. 6, figs. 1, 3, October,
1908. “U.S.S. ‘Albatross,’ station 3369, near Cocos Island, Gulf of
Panama, in 52 fathoms, rocky bottom, temperature 62.2°F.,
U.S.N. Mus. 122,870.”

(486) Cyclopecten acutus Grau, Allan Hancock Pac. Exped., Vol.
23, p. 31, pl. 10, fig. 2, September 25, 1959. “Off northside of Gor-
gona Island, western Colombia, in 32 fathoms.”

(487) Cited as “S. F. Limaridia” by Rafinesque, 1815. Also as
“Famille des Limidae” by d’Orbigny, 1846.

(488) See Cox, L. R., Mem. Geol. Surv. India, Palaeont. Indica,
Ser. 9, Vol. 3, Pt. 4, pp. 47-49, 1952. See also Cox, Proc. Malacol.
Soc. London, Vol. 25, Pts. 5 and 6, pp. 152, 154, 156, 1943.

(489) According to L. R. Cox (written comm.) this work was is-
sued between September 22 and December 24, 1797).

(490) Lima inflata Lamarck (Ann. Mus. Hist. Nat. Paris, Vol. 8,
p- 463, 1806 (1807)), also was based upon pl. 68, fig. 649a of Chem-
nitz. Not Ostrea inflata Gmelin, Syst. Nat., ed. 13, Vol. 1, Pars 6,
p. 3321, 1791. Ref. to Born (Mus. Vindobonensis, pl. 6, figs. 7, 8,
and Chemnitz, Vol. 7, pl. 68, fig. 649b).

(491) Promantellum Iredale, Brit. Mus. (Nat. Hist.) Great Bar-
rier Reef Exped. 1928-1929. Sci. Repts., Vol. 5, No. 6, Moll., Pt. 1,
p. 885, February 25, 1939. “Type: P. parafragile sp. nov.,” p. 386,
pl. 6, figs. 10, 10a. “Low Isles,” Great Barrier Reef Australia.
(492) Submantellum Olsson and Harbison, Acad. Nat. Sci.
Philadelphia, Monogr. No. 8, p. 60, November 6, 19538. ‘Type:
Lima orbignyi Lamy (Lima angulata Sowerby, not Miinster).”
(493) Studnitz, G. von., “Die Morphologie und Anatomie von
Lima inflata, der Feilenmuschel, nebst biologischen Unter-
suchungen an Lima hians Gmel.,” Zool. Jahrb., Abt. Anat., Bd.
53, pp. 199-316, 1931. See also Gilmour, T. H. J., “The defensive
adaptations of Lima hians (Mollusca, Bivalvia),” Jour. Mar.
Biol. Assoc. U. K., Vol. 47, pp. 209-221, pl. 1, figs. 1-5 in text.
(494) Lima (Limaria) hemphilli, Hertlein and Strong, Zoolog-
ica, Vol. 31, Pt. 2, No. 5, p. 66, pl. 1, figs. 3, 4, August 20, 1946.
“San Diego, California.” Recent.

(495) Lima orbignyi Lamy, Jour. de Conchyl., Vol. 74, No. 3, p.
180, November 29, 1930. New name for Lima angulata Sowerby,
1843, not Lima angulata Minster, 1841. See also Hertlein and
Strong, Zoologica, Vol. 31, Pt. 2, No. 5, p. 67, 1946.

(496) Lima auaua Dall, Bartsch, and Rehder, Bernice P. Bishop
Mus., Bull. 153, p. 106, pl. 27, figs. 5-8, July 25, 1988. Dredged “in
Auaua Channel between Maui and Lanai, in 28-43 fathoms on
sand and gravel bottom; bottom temperature, 74.0°F.”

(497) Cited as Family “Ostraceae” by Oken, 1818; also as “Fam-
ilie. Ostracea” by Goldfuss, 1820; as “Division” “Ostraceae” by
Bowdich, 1822; as “Ostraceae” by Parkinson, 1822; as ‘Order Os-
treadae” by Fleming, 1822; as ‘Fam. I.-Ostracés Ostracea” by
Deshayes, 1824.

(498) “Ostreacia” Rafinesque, 1815, p. 21. Corrected to Os-
treidae. See Internatl. Comm. Zool. Nomencl., Opinion 356,
signed February 8, 1955, published August 12, 1955.

(499) Newell, N. D., “Origin of the oysters,’’ Bull. Geol. Soe.
Amer., Vol. 71, No. 12, Pt. 2, p. 1936, 1960. See also, Report Inter-
natl. Geol. Congr. XXI Session, Norden, 1960, Part XXII, Inter-
natl. Paleon. Union. 1960, Copenhagen, pp. 81-86, 1 fig.

(500) Stenzel, H. B., “Nomenclatural Synopsis of Supraspecifie ©
Groups of the family Ostreidae (Pelecypoda, Mollusca), Jour.
Paleo., Vol. 21, No. 2, pp. 165-185, March, 1947.

(501) Baughman, J. L., Annotated bibliography of oysters, with
pertinent material on mussels and other shellfish, and an appen-
dix on pollution, Texas A. and M. Res. Found., College Station, —

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Texas, 794 pp., 1947.

(502) See Weinkauff, H. C., “Die Conchylien des Mittelmeeres,”
Bd. 1, p. 278, 1867 (Ostrea cochlear Poli). See also Dautzenberg,
Ph., and Fischer, H., Res. Campag. Sci. du Prince de Monaco,
Fasc., 32, pp. 63-64, 1906.

(503) See Keen, A. M., and Bentson, H., Geol. Soc. Amer., Spec.
Papers No. 56, pp. 74-79, 1944.

(504) See Hertlein, L. G., “Notes on California Oysters,” Veli-
ger, Vol. 2, No. 1, pp. 5-9, pl. 2, July 1, 1959.

(505) For a discussion of this species see Galtsoff, P. S., “The
American Oyster Crassostrea virginica.” Fish. Bull. Fish Wild-
life Serv., Vol. 64, pp. 1-480, figs. 1-400, 1964.

(506) See Keen, A. M., Sea shells of Tropical West America
(Stanford Univ. Press), pp. 65-68, 1958, and Olsson, A. A., Mol-
lusks of the Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), pp. 171-175, 1961.

(507) Lamy, E., ‘“Révision des Ostrea vivants du Muséum Na-
tional d’Histoire Naturelle de Paris,” Jour. de Conchyl., Vol. 73,
No. 1, pp. 1-46, figs. 1-3, April 30, 1929; Vol. 73, No. 2, pp. 71-108,
July 20, 1929; Vol. 73, No. 3, pp. 183-168, October 30, 1929; Vol. 73,
No. 4, pp. 283-275, pl. 1, February 28, 1930.

(508) Hirase, S., “On the classification of Japanese oysters,”
Jap. Jour. Zool., Vol. 3, No. 1, pp. 1-65, figs. 1-95, March 30, 1950.
Also “Some more species of Japanese oysters,” Jap Jour. Zool.,
Vol. 4, No. 2, pp. 213-222, figs. 1-4, July 30, 1932. See also, Oyama,
K., “Preliminary notes on the ostreid Phylogeny,” Ann. Zool.
Jap., Vol. 25, Nos. 1, 2, pp. 337-342, January, 1952.

(509) Thomson, J. M., “The genera of oysters and the Austra-
lian species,” Australian Jour. Mar. Freshwater Res., Vol. 5, No.
1, pp. 132-168, pls. 1-11, 1954.

(510) “Ostrea var. laticaudata, Nutt. MS,” Carpenter, Rept.
Brit. Assoc. Adv. Sci. for 18638, p. 646, issued August, 1864. In-
dicated as from “Neighborhood of S. Francisco.” Reprint ‘in
Smithsonian Mise. Coll., No. 252, p. 122, 1872. See also Ostrea lu-
rida forma laticaudata Carpenter, Hertlein, Veliger, Vol. 2, No.
1, p. 7, pl. 2, figs. 7, 8, 1959. San Pedro, California, Recent.

(511) Ostrea (Alectryonia?) caboblancoensis Weisbord, Bull.
Amer. Paleo., Vol. 45, p. 190, pl. 25, figs. 1-6, February 18, 1964.
(512) See Hertlein, L. G., and Allison, E. C., Bull. South. Calif.
Acad. Sci., Vol. 58, Pt. 1, p. 21, 1959 (as Ostrea vespertina
veatchii).

(513) See Durham, J. W., Geol. Soc. Amer., Mem. 43, Pt. 2, p. 58,
1950 (as Ostrea cwmingiana). See also, Emerson, W. K., and
Hertlein, L. G., 1964, pp. 349, 353.

(514) Willett, G., Bull. South. Calif. Acad. Sci., Vol. 45, Pt. 1, p.
29, 1946.

(515) Durham, J. W., Geol. Soc. Amer., Mem. 43, Pt. 2, p. 59, pl. 4,
fig. 2, 1950.

(516) See Vokes, H. E., in Wilson, I. F., Bull. Amer. Assoc. Pet-
rol. Geol., Vol. 32, No. 9, p. 1782, 1948. Also U.S.G.S., Prof. Paper
278, p. 32, 1955.

(517) Ostrea ?conchaphila, var. palmula Carpenter, Cat. Mazat-
lan Shells, pp. 168, 550. March, 1856. “Mazatlan; extremely rare;
L’pool Col. -S. W. Mexico, P. P. C.—Upper California, Nuttall.”
See also Hertlein and Strong, Zoologica, Vol. 31, Pt. 2, p. 55, pl. 1,
fig. 14, 1946 (as Ostrea palmula). Illustration of interior of upper
(right) valve of type specimen. Various localities cited. See also
Keen, A. M., Sea Shells of Tropical West America, p. 66, fig. 124
(p. 69), 1958; and Olsson, 1961, p. 173, pl. 17, figs. 6, 6a; pl. 28, figs.
5, 5a, 7, 7a.

(518) Ostrea vespertina Conrad var sequens Arnold, U.S.G.S.,
Bull. 396, p. 79, pl. 29, figs. 5, 6, 1909 (issued January 15, 1910).
_ From Loe. 4728, “just below Anodonta bed on northeast border
of Kettleman Hills, nearly 6 miles east-southeast of northwest
end, in north part of sec. 35, T. 21 S., R. 17 E.” “Horizon.—Ex-
_ treme top of the Etchegoin formation, upper Miocene, just below
Tulare bed (Anodonta fresh-water bed).”’ See also Woodring, in
Woodring, Stewart, and Richards, 1940 (1941), p. 92, pl. 8, figs.

309

10-14.

(519) Ostrea conchaphila Carpenter, Cat. Mazatlan Shells, p.
161, 1855. ‘‘Hab.—Mazatlan; not uncommon, on various shells,”
also other localities. See also Hertlein, L. G., and Strong, A. M.,
Bull. Amer. Mus. Nat. Hist., Vol. 107, Art. 2, p. 179, pl. 3, figs. 29,
30, 1955. Redondo, California, to the Gulf of California and south
to Panama.

(520) Ostrea lurida Carpenter, Rept. Brit. Assoc. Adv. Sci. for
1863, pp. 599, 606, 615, 645, issued August, 1864. Cited from vari-
ous localities including Vancouver Island, Puget Sound, Oregon,
and near San Francisco. See also Palmer, K. V. W., Geol. Soe.
Amer., Mem 76, p. 66, pl. 5, figs. 4-6, 1958. “Recent. [Cape]
Shoalwater [‘Bay’] northern Willapa Harbor, Washington
(type).”

(521) See Hertlein, L. G., The Veliger, Vol. 2, No. 1, pp. 6, 7, pl. 2,
figs. 1, 2 (typical), 3, 6, 7, 8, 9, 11 (vars.), 1959.

(522) Ostrea heermanni Conrad, Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 7, p. 267, February, 1855. “Colorado Desert. Dr.
Heermann. Shell silicified.”"—Hanna, Proc. Calif. Acad. Sci., Ser.
4, Vol. 14, No. 18, p. 467, pl. 22, figs. 7, 8; pl. 23, figs. 1, 2, 1926.
(523) Ostrea sculpturata Conrad, Fossils of the Medial Tertiary
of the United States, No. 2, p. 50, pl. 25, fig. 3, May 7, 1840.
“James river, near Smithfield, Va.” See also reprint by Wagner
Free Inst. Sci., 1893.

(524) See Mansfield, W. C., “Miocene Pelecypods of the Choc-
tawhatchee formation of Florida,” Florida State Geol. Surv.,
Bull. No. 8, p. 56, pl. 8, figs. 2, 3, 1932.

(525) Ostrea (Alectryonia) vespertina venezuelana Weisbord,
Bull. Amer. Paleo., Vol. 45, No. 204, p. 187, pl. 24, figs. 5-11, Feb-
ruary 18, 1964. Playa Grande Formation (Catia member).

(526) Ostrea vespertina Conrad, Deraniyagala, Spolia Zeyla-
nica, Bull. Nat. Hist. Mus. Ceylon, Geol. Zool. Anthropol., Vol. 28,
Pt. 1, p. 2, pl. 2, fig. 1, June 25, 1956. “Miocene Amphitheatre at
Minihagalkanda, Ceylon.” (In text reference to Ostrea vesper-
tina “‘Deshayes.”’)

(527) Masson, P., and Alencaster-Ibarra, Gloria, Bol. Assoc.
Mexicana Geol. Petrol, Vol. 3, Nos. 5-6, p. 206, figs. 8-11, 1951.
(528) See Khomenko, I. P., Mém. Soe. Russ. Miner., Vol. 60,
Livr. 1, p. 106, 1931. Baron Korf Gulf, Kamtschatka, middle Mio-
cene.

(529) See Nomland, J. O., “Fauna of the Santa Margarita beds
in the North Coalinga region of California,” Univ. Calif. Publ.
Bull. Dept. Geol., Vol. 10, No. 18, p. 300, 1917.

(530) See Dall, W. H., Nautilus, Vol. 28, No. 1, p. 1, May, 1914.
(531) Ostrea wiedey?i Hertlein, Jour. Paleo., Vol. 2, No. 2, p. 147,
pl. 28, figs. 1, 10, June, 1928. “from oyster bed near spring on
ridge south of San Augustine Canyon, about 1.6 to 2 kilometers
from mouth of canyon, Santa Rosa Island, California.” Va-
queros, early Miocene.

(532) See Loel, W., and Corey, W. H., Univ. Calif. Publ., Bull.
Dept. Geol. Sci., Vol. 22, No. 3, p. 193, pl. 16, figs. la, 1b.; pl. 17,
figs. la, 1b, 2a, 2b, 3, December 31, 1932.

(533) See Maury, C. J., Bull. Amer. Paleo., Vol. 10, No. 42, p. 230
(78), pl. 20 (9), fig. 1, 1925. Trinidad, late Miocene.

(534) Ostrea haitensis Sowerby, Quart. Jour. Geol. Soc. London,
Vol. 6, p. 58, 1850 (issued May 16, 1849). “Tertiary beds in San
Domingo.”

(535) See Davies, A. M., Quart. Jour. Geol. Soe. London, Vol. 79,
Pt. 4, pp. 588-589, 1923. Also Tertiary Faunas (London), Vol. 2,
pp. 160-161, 1934.

(536) See Cox, L. R., “Neogene and Quaternary Mollusca from
the Zanzibar Protectorate. Report on the Paleontology of the
Zanzibar Protectorate” (London), pp. 66-69, pl. 11, figs. 1, 2; pl.
16, fig. 1, 1927.

(537) See Dall, W. H., U.S.G.S., 17th Ann. Rept., Pt. 1, p. 844,
1895 (1896). Cited from Miocene of Atka Island and Unga Island,
Alaska.

(538) See Weaver, C. E., Univ. Washington Publ. Geol., Vol. 1,

360

No. 1, p. 28, 1916. From Loc. 230 (U.W.), Chehalis Co., Washing-
ton, lower Miocene.—Weaver, Washington Geol. Surv., Bull. No.
18, pp. 170, 174, 1916. “Grays Harbor County.” ‘Lower Mio-
cene.”— Weaver, Calif. Acad. Sci., Ser. 4, Vol. 6, No. 2, p. 36, 1916.
“Yoldia strigata Zone.” Western Washington, Miocene.

(539) See discussion by Hertlein, L. G., Bull. South. Calif. Acad.
Sci., Vol. 56, Pt. 2, p. 66, May-August (issued August 31), 1957.
(540) Lopha Réding in Bolten, Mus. Bolt., Pt. 2, p. 168, 1798.
Species cited: Lopha crista-galli, L. hyotis, L. frons, L. folium, L.
cornu copiae, L. theca, L. plicatella. Type (designated by Dall,
Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 4, p. 672, 1898): “Type
Ostrea crista-galli Linné.” Syst. Nat., ed. 10, p. 704, 1758 (as My-
tilus crista galli). Ref. to “Rumph. mus. t. 47. f. D.”; “Gualt. test.
t. 104. f. C.D.E.”; “Argenv. conch. t. 28. f. D.” Habitat in O. In-
dici Gorgoniis.”” Illustrated by Sowerby, Conch. Icon., Vol. 18,
Ostraea, sp. 22, pl. 11, figs. 22a, b, ec, 1871. “Hab. Indian Ocean.”
(541) Gillet, S., “Etudes sur les Lamellibranches Néocomiens,”
Mém. Soc. Géol. France, Nouv. Sér., Vol. 1, Fase. 3 and 4, Mém.
No. 3, p. 71, 1924.

(542) Arctostrea Perivinquiére in Douvillé, Bull. Soc. Géol.
France, Sér. 4, Vol. 10, p. 119, 1910. Type: Ostrea carinata
Lamarck, Ann. Mus. Hist. Nat. (Paris), Vol. 8, p. 166, 1806. (Ref.
to “Encyclop. pl. 187, f. 3, 4, 5.”) “Fossile de Cany, départment de
Seine-Inférieure.”’ Cenomanian, Cretaceous.—Fabre, “Catalogue
Illustré de la Collection Lamarck,” Mus. Hist. Nat. Genéve, Con-
chiféres monomyaires Fossiles, Sect. 2, pl. 20, figs. 66a, 66b, 67a,
67b [67a on pl.] 1917. See also the discussion of Arctostrea by
Sohl and Kauffman, U.S.G.S., Prof. Paper 483-H, pp.H13-H14,
1964; Carter, Palaeontology, Vol. 11, Pt. 3, pp. 458-485, 1968.
(543) Galtsoff, P. S., "The Pearl-Oyster Resources of Panama,”
U.S. Dept. Interior, Fish Wildlife Serv., Spec. Sci. Rept.: Fish.,
No. 28, p. 30, May, 1950.

(544) Ostrea megodon cerrosensis Gabb, Woodring, Bramlette,
and Kew, U.S.G.S., Prof. Paper 207, p. 81, pl. 30, fig. 11, 1946.
“Lomita marl.”

(545) Ostrea (Lopha) paramegodon Woodring, Carnegie Inst.
Washington, Publ. No. 366, p. 60, pl. 6, figs. 12-14, May 20, 1925.
(546) Ostrea megodon Hanley, Maury, Bull. Amer. Paleo., Vol. 5,
No. 29, p. 347 (183), pl. 60 (34), fig. 3, 1917. ““Guayubin to Mao
road, and the Teredo Zone, Rio Cana at Caimito,”’ Dominican Re-
public, Miocene.

(547) Ostrea megodon Hanley, Olsson, Bull. Amer. Paleo., Vol. 9,
No. 39, p. 367 (195), pl. 21 (18), fig. 1, June 21, 1922. “Gatun
stage,’”’ Miocene, Costa Rica.

(548) Ostrea messor Maury, Bull. Amer. Paleo., Vol. 10, No. 42,
p. 233 (81), pl. 21 (10), figs. 3, 4, March 27, 1925. “Springvale,”
Trinidad, “Upper Miocene.”

(549) Ostrea megadon Hanley, Anderson, Proce. Calif. Acad. Sci.,
Ser. 4, Vol. 18, No. 4, p. 154, 1929.

(550) See Weisbord, N. E., Bull. Amer. Paleo., Vol. 45, No. 204,
pp. 193-194, 1964.

(551) Cited as "S.F. Anominia” [subfamily of Ostreacia] by
Rafinesque, 1814; as “Familia Anominea” by Herrmannsen,
1846; as “Superfamily Anomiacea” by Dall, 1895.

(552) Cited as “The fourth... family ... is the Anomiae” by
DaCosta, 1776; Family “Anomiadae” by Gray, 1840.

(553) See Merrill, A. S., “Variation and change in surface sculp-
ture in Anomia aculeata,” Nautilus, Vol. 75, No. 4, pp. 131-138,
pl. 14, 1962. See also remarks by David Nicol, Nautilus, Vol. 78,
No. 4, pp. 110-111, 1965.

(654) Boulenger, E. G., “Natural History of the Seas” (New
York), p. 97, 1935.

(555) Winckworth, R., “Note on the British Species of Anomia,”
Proc. Malacol. Soc. London, Vol. 15, Pt. 1, pp. 32-34, pl. 1, April,
1922.

(556) Loosanoff, V. L., “Partial Metamorphosis in Anomia sim-
plex,” Science, Vol. 138, No. 3470, pp. 2070-2071, fig. 1, June 30,
1961.

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

(557) See Anomia fidenas Gray, Olsson, Mollusks of the Tropi-
cal Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York), p. 177,
pl. 24, figs. 4, 4a, 1961, Panama.

(558) Anomia adamas Gray, Proc. Zool. Soc. London for 1849, p.
117 (issued between January and June, 1850). ‘““Hab. Galapagos
Islands; Lord Hood’s Island, attached to Avicula margaritifera
at nine fathoms.’’—Reeve, Conch. Icon., Vol. 11, Anomia, sp. 15,
pl. 3, fig. 15, 1859.

(559) Jordan, E. K., ‘The Pleistocene Fauna of Magdalena Bay,
Lower California,” Contrib. Dept. Geol. Stanford University,
Vol. 1, No. 4, p. 121, 1936.

(560) See Dautzenberg, P., and Bouge, J. -L., “Les Mollusques
Testacés Marins des Etablissements Francais de Océanie,” Jour.
de Conchyl., Vol. 77, No. 3, pp. 421-422, 1933.

(561) Hanna, G D., “Paleontology of Coyote Mountain, Imperial
County, California,” Proc. Calif. Acad. Sci., Ser. 4, Vol. 14, No.
18, p. 460, pl. 23, figs. 3, 4, 5, March 23, 1926.

(562) See Arnold, R., Mem. Calif. Acad. Sci., Vol. 3, p. 118, 1903.
(563) See Keen, A. M., The Veliger, Vol. 2, No. 1, p. 1, pl. 1, fig. 2,
July 1, 1959.

(564) See von Ihering, H., An. Mus. Nac. Buenos Aires, Vol. 14,
(ser. 3a, Vol. 7) pp. 266-269, 1907.

(565) Pododesmus puntarenensis Soot-Ryen, Arkiv f. Zool., Ser.
2, Bd. 4, Heft 4, No. 15, p. 308, pl. 1, figs. 8, 9, 1953.

(566) Pers. comm., June 16, 1959.

(567) Vokes, H. E., “Molluscan Faunas of the Domengine and
Arroyo Hondo Formations of the California Eocene,” Ann. New
York Acad. Sci., Vol. 38, p. 57, pl. 3, figs. 6, 7, 9, 11, 1939.

(568) See Hayami, I., Mem. Fae. Sci., Kyushu Univ., Ser. D,
Geol., Vol. 15, No. 2, pp. 335-336, pl. 47, figs. 10, 11; pl. 48, fig. 1,
March 1, 1966.

(569) See Hatai, K., and Nisiyama, S., “Checklist of Japanese
Tertiary Marine Mollusca,” Sci. Repts. Tohoku Univ., Sendai, Ja-
pan, Second Ser. (Geology), Special Vol. No. 3, p. 180-181, 1952.
(570) Pododesmus macroschisma Deshayes, Slodkewitsch, Ter-
tiary Pelecypoda from the Far East, Pt. 1, Paleontology of
USSR., Vol. 10, Pt. 3, Fasc. 18, p. 215, and Fase. 19, p. 114, pl. 44,
figs. 1, la, 1b; figs. 2 and 3 (reproductions of original figures from
Deshayes), 1938.

(571) See Fitch, J. E., Calif. State Dept. Fish Game Mar. Fish.
Branch, Fish Bull. No. 90, p. 45, fig. 11, 1953. British Columbia to
San Quintin Bay, Lower California.

(572) Placunanomia cepio Gray, Proe. Zool. Soc. London for
1849, p. 121, issued between January and June, 1850. “Hab. Cali-
fornia; Lady Katherine Wigram; Brit. Mus.’’—Reeve, Conch.
Icon., Vol. 11, Placunanomia, sp. 12, pl. 3, figs. 12a, 12b, 1859.
(573) Placunanomia alope Gray, Proc. Zool. Soc. London for
1849, p. 122, issued between January and June, 1849. “Hab. Cali-
fornia.”"—Reeve, Conch. Icon., Vol. 11, Placunanomia, sp. 11, pl.
3, figs. 1la, 11b, 1859.

(574) Frizzell, D. L., Nautilus, Vol. 43, No. 3, p. 104, January,
1930.

(575) See Pavlovsky, E. N. (editor), Atlas of the Invertebrates
of the Far Eastern Seas of the USSR [Translation], Acad. Sci.
Zool. Inst., Moscow-Leningrad, p. 191, pl. 51, fig. 3, 1955 (as
Anomia macrochisma).

(576) See Habe, T., Illustrated catalogue of Japanese shells,
(Edited by Dr. Tokubei Kuroda), No. 24, p. 200, pl. 28, figs. 22, 23,
1953 (as Monia macrochisma).

(577) Carpenter, P. P., Rept. Brit. Assoc. Adv. Sci., for 1863, p.
525, 1864. See also p. 646. Reprint in Smithsonian Miscell. Coll.,
No. 252, pp. 11 and 182, 1872.

(578) The original spelling of the specific name of this species is
“‘macrochisma.” Some authors have inserted an “'s” as the sixth
letter in the trivial name. We retain the original orthography.
(579) Burch, J. Q., Min. Conch. Club South. Calif., No. 127, p. 7,
March-April, 1953.

(580) Pododesmus macroschismus (Deshayes) var ezoanus

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Kanehara, Jap. Jour. Geol. Geogr., Vol. 18, No. 4, p. 136, pl. 15,
fig. 1; pl. 16, figs. 1, 2, December, 1942. Setana Series of Yuno-
sawa, Kuromatsu-nai, Suttsu-gun, Shiribeshi, Hokkaido; Plio-
Pleistocene. [Pliocene according to Hatai and Nisiyama, Sci.
Repts. Tohoku Univ. Sendai, Japan, Ser. 2 (Geol.), Spee. Vol. No.
3, p. 181, 1952.]

(581) Pododesmus newcombei Clark and Arnold, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 5, p. 141, pl. 21, figs. 3, 4,
5, 6, November 6, 1923. Stanford Univ., Loc. N.P. 130, “Sooke ba-
sal sandstones; sea cliffs at mouth of Fossil Creek, 2 miles west
of Sherringham Point, Jordan River, Vancouver Island.”

(582) Placunanomia foliata Broderip, Proc. Zool. Soc. London
for 1834, p. 2, May 14, 1834. “Hab. in sinu Guayaquil Columbiae
Occidentalis. (Isle of Muerte.)” “Dredged up attached to a dead
Pinna from a bottom of sandy mud, at the depth of eleven fath-
oms.”’—Reeve, Conch. Icon., Vol. 11, Placunanomia, sp. 5, pl. 1,
fig. 5, August, 1859.—Olsson, Moll. Trop. East Pacific (Paleo. Res.
Inst.: Ithaca, New York), p. 178, pl. 24, figs. 3, a-d, 1961 (as Podo-
desmus foliatus). Gulf of California to Peru.

(583) Cited as “Division” “Camaceae” by Bowdich, 1822; as
“Chamaceae” by Parkinson, 1822; as “Fam. VII.—Camacea’”’ by
Blainville (Dict. Sci. Nat., Vol. 32, p. 326, 1824; Man de Conchyl.,
p. 541, 1825).

(584) Chamidae Blainville placed on official list of family-group
names in Zoology by Internatl. Comm. Zool. Nomencl., Opinion
484, signed June 24, 1957, and published October 10, 1957.

(585) Nicol, D., ‘"Nomenclatural Review of genera and subge-
nera of Chamidae,” Jour. Washington Acad. Sci., Vol. 42, No. 5,
pp. 154-156, May 15, 1952.

(586) Pilsbry, H. A., and Lowe, H. N., “West American Cha-
midae, Periploma and Glycymeris,” Nautilus, Vol. 47, No. 3, pp.
81-86, pl. 8, January 26, 1934. See also Hertlein, L. G., and
Strong, A. M., Zoologica, Vol. 31, Pt. 3, pp. 108-111, 1946.—Keen,
Sea Shells of Tropical West America (Stanford Univ. Press;
Stanford, California), pp. 108-112, 1958.—Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York, pp.
222-227, 1961).

(587) Chama was placed on the official list of generic names in
Zoology by the Internat]. Comm. Zool. Nomencl., Opinion 484,
signed June 24, 1957, published October 10, 1957. Type species,
Chama lazarus Linnaeus, selected by Children, 1823.

(588) See Douvillé, H., Compt. Rend. Somm. Seance. Soc. Géol.
France for 1931, Fase. 14 and 15, p. 204, 1931.

(589) See Dall, W. H., Trans. Wagner Free Inst. Sci., Vol. 3, Pt.
6, pl. 58, fig. 1, 1903. _

(590) Grieser, E., “Uber die Anatomie von Chama pellucida
Broderip,” Zool. Jahrb., Suppl. Bd. 18 (Fauna chilensis, Bd. 4,
Heft 2), pp. 207-280, 1 pl., figs. 1-11, 1913.

(591) Chama chilensis Philippi, Los Fésiles Terciarios I Cuar-
tarios de Chile (Santiago), p. 173, pl. 37, fig. 9, 1887. “Cuartario
de Cahuil.”

(592) Cited as “Fam. 4. Crassatellacea” by Menke, 1830; as
Family Crassatellidae by Gray, 1840; as “Familie Astartacea”
by Philippi, 1853, and by Catlow, 1854.

(593) See Crassatella (Pseuderiphyla) remiensis Cossmann and
Pissaro, Icon. Compl. Coq. Fossil de |’Eocéne des Environs de
Paris, Tom. 1. Péléeypodes, pl. 45, fig. 96-24, 1906. “Cernay,”
Thanétien, Eocéne. See also Crassinella dalli von Ihering, An.
Mus. Nac. Buenos Aires, Tom. 14 (Ser. 3a, Tom. 7), p. 280, fig. 12
(a, b), 1907. ‘Formation patagonienne inférieure.”

(594) See Crassinella sp., Mansfield, Jour. Paleo., Vol. 14, No. 3,
_p. 189, pl. 25, figs. 16, 17, May, 1940. “lower part of the Chick-
asawhay marl.” Mississippi. “Upper Oligocene.”

(595) See Woodring, W. P., Bramlette, M. N., and Kew, W.S. W.,
U.S.G.S., Prof. Paper, 207, p. 27, pl. 28, fig. 12, 1946. Altamira
Member of Monterey Shale, Palos Verdes Hills, California,
middle Miocene.

(596) Gouldia pacifica C. B. Adams, Ann. Lyceum Nat. Hist.

361

New York, Vol. 5, pp. 499, 545 (separate pp. 275, 321), July, 1852.
“Panama.”’—Turner, Occ. Papers on Moll., Dept. Moll., Mus.
Comp. Zool., Harvard Univ., Vol. 2, No. 20, p. 69, pl. 20, figs. 3-4,
1956.
(597) Crassinella mexicana Pilsbry and Lowe, Proc. Acad. Nat.
Sci. Philadelphia, Vol. 84, p. 103, pl. 14, figs. 8, 9, May 21, 1932.
“Mexico: Guaymas, in about 20 fathoms (Lowe).”
(598) Crassinella quintinensis Manger, Johns Hopkins Studies
in Geol., No. 11, p. 298, pl. 21, figs. 1, 2, 1934. “San Quintin Bay,
Lower California,” Pleistocene.
(599) See Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 31,
Pt. 3, No. 8, p. 104, 1946.
(600) See Hoffstetter, R., Bol. Inform. Cienc. Nac., Vol. 2, Nos.
13, 14, p. 74, 1948. Tercer Tablazo [youngest], Sta. Elena Penin-
sula, Ecuador.
(601) Cited as “Carditadae” by Fleming, 1828; as Family “Car-
ditacea” by Menke, 1830; as Family “Carditidae” by d’Orbigny,
1846, p. 723.
(602) See Freneix, S., ““Remarques sur l’ontogénie du ligament
et de la charniére de quelques espéces Lamellibranches (Noetidae
et Carditidae),” Bull. Soc. Géol. France, Sér. 7, Tome 1, No. 7, pp.
719-730, figs. 1-3, pls. 33-34, 1959. Issued June, 1960. (Carditidae,
pp. 725-728, fig. 3 (A-D), pl. 34, figs. 4-10).
(603) Yonge, C. M., “Functional morphology and evolution
within the Carditacea (Bivalvia),” Proc. Malacol. Soe. London,
Vol. 38, Pt. 6, pp. 493-527, figs. 1-25 in text, December, 1969.
(604) See Sorgenfrei, T., “Molluscan assemblages from the ma-
rine middle Miocene of South Jutland and their environments,”
Vol. 1. Reprinted from Geol. Surv. Denmark. II. Ser. No. 79, p.
85, 1958.
(605) See discussion by Dodge, H., Bull. Amer. Mus. Nat. Hist.,
Vol. 100, Art. 1, pp. 132-133, 1952.
(606) Soot-Ryen, T., Norske Vidensk. -Akad. Oslo. Sci. Res. Nor-
wegian Antarctic Exped., 1927-28, et seq., No. 32, p. 24, 1951.
(607) Finlay, H. J., and Marwick, J., Trans. Proc. Roy. Soc. New
Zealand, Vol. 70, Pt. 1, pp. 114, 121, 1940.
(608) Sieber, R., Ann. Naturhist. Mus. Wien, Bd. 60, p. 177, De-
cember, 1955.
(609) Hirayama, K., Sci. Repts. Tokyo Kyoiku Daigaku, Sec. C,
(Geol. Min. Geogr.), No. 29, pp. 84-85, March 10, 1955.
(610) Chavan, A., Bull. Soc. Géol. France, Sér. 5, Vol. 19, pp. 511-
512, 1949.
(611) Woods, S., Palaeontogr. Soc. London, Vol. 27, Suppl. Crag
Molk., Vol. 3, Univalves and Bivalves, p. 131, for 1873 (1874).
(612) See “Cardita” aff. C. occidentalis Conrad, Woodring, W.
P., Bramlette, M. N., and Kew, W.S. W., U.S.G.S., Prof. Paper
207, p. 82, pl. 33, fig. 4, 1946. Loe. 66 (U.S.G.S.) “North border of
hills, ravine 1,000 feet east of Crenshaw Blvd. Timms Point
Silt.” Also other localities.
(613) Smith, A. G., and Gordon, M., Proc. Calif. Acad. Sci., Ser.
4, Vol. 26, No. 8, pp. 213-216, December 18, 1948.
(614) Quayle, E. H., “Conchometry of California Carditas,”
Sixth Pac. Sci. Conference. Abstracts, Tertiary Stratigraphy
(mimeographed: Berkeley, California), p. 22, 1939.
(615) Willett, G., Bull. South. Calif. Acad. Sci., Vol. 45, Pt. 1, pp.
29, 30, 1946.
(616) Venericardia (Cyclocardia) stearnsii Dall, Proce. Acad.
at. Sci. Philadelphia, Vol. 54, p. 709, January 20, 1903. “Puget
Sound, with V. ventricosa, U.S. Exploring Expedition under Wil-
kes.”—Dall, Proc. U.S. Nat. Mus., Vol. 13, p. 216, pl. 16, figs. 5, 6,
1890 (as Venericardia ventricosa Gould). See also I. S. Oldroyd,
Publ. Puget Sound Biol. Sta., Vol. 4, p. 36, pl. 46, figs. 9, 10, 1924.
[This species was recorded by Twenhofel as occurring in Pleisto-
cene terrace material on Douglas Island, Alaska (see Amer.
Jour. Sci., Vol. 250, p. 545, July, 1952).]
(617) Venericardia (Cyclocardia) californica Dall, Trans. Wag-
ner Free Inst. Sci., Vol. 3, Pt. 6, p. 1431, pl. 56, fig. 16, October,
1903. “Pliocene (?) of California, five miles southeast of Guada-

362

lupe; G. H. Eldridge.” [California.] See also illustrations by
Woodring, in Woodring and Bramlette, U.S.G.S., Prof. Paper
222, p. 85, pl. 8, fig. 16; pl. 10, figs. 7, 8; pl. 11, figs. 2, 3; pl. 15, figs.
1, 2; pl. 21, fig. 5, 1950. Santa Maria district, California. Pliocene.
[Woodring pointed out that “According to the preservation and
matrix of the type lot, the type locality is the Waldorf asphalt
mine.”’]

(618) See Hertlein, L. G., Stanford. Univ. Bull., Fifth Ser., No.
78, p. 85, 1929. Pliocene... San Diego Fauna.

(619) Cardita monilicosta Gabb var. ochotica Slodkewitsch,
Paleo. USSR, Acad. Sci., USSR, Vol. 10, Pt. 3, Fasc. 18, p. 294,
1938; Fase. 19, pp. 131-132, pl. 61, figs. 1, la, 2, 2a, 2b, 3, 1938.
“Sea coast, between Amanina and Etalonnaya rivers (western
coast of Kamtschatka).” “Not uncommon in the upper horizons
of Kavran series.” [ Pliocene. }

(620) Tikonovich, N., Mém. du Comité Géol., New Sér., Livr. 82,
pp. 86, 148, 1914.

(621) Cardita (Cyclocardia) ventricosa montereyensis Smith
and Gordon, Proc. Calif. Acad. Sci., Ser. 4, Vol. 26, No. 8, p. 212,
figs. 2A, B, 3A, B, in text, December 15, 1948. “Dredged in 63
fathoms about 4.6 miles northwest of Point Pinos, in fine sand,
sand pellets, and pebbles, Monterey Bay, California.”

(622) Cardita ventricosa redondoensis J. Q. Burch, in T. Burch,
Min. Conch. Club South. California, No. 39, p. 14, 2 figs. (on p. 15
as “Cardita sp.”), September, 1944. ‘Redondo Beach, California”’
100 fathoms - mud.”—J. Q. Burch, Min. Conch. Club South. Cali-
fornia, No. 47, p. 32, pl. 2, figs. 40, 41, April, 1945 (as Cardita re-
dondoensis). “Redondo Beach.”

(623) See Wood, S. V., Palaeontogr. Soc. London, Vol. 27, Suppl.
Monogr. Crag Moll., Vol. 3, Pt. 2, Bivalves, p. 131, 1872-1874 (is-
sued for 1873). Ref. to “Cardita scalaris, Leathes,” Monogr.
Crag Moll., Vol. 2, Bivalves [in Palaeontogr. Soc., Vol. 71, p. 166,
pl. 15, fig. 5, 1853. P
(624) Venericardia (Cyclocardia) inflata Hayasaka and Uo-
zumi, Jour. Fac. Sci. Hokkaido Univ., Ser. IV, Geol. Min., Vol. 8,
No. 4, p. 400, pl. 25, figs. 5, 5a, 6, March, 1954.

(625) See Barnard, J. L., and Ziesenhenne, F. C., Pac. Nat., Vol.
2, No. 2, p. 147, (see fig. 6), January 13, 1961.

(626) Jones, G. F., “Brood Protection in three southern Califor-
nia species of the pelecypod Cardita,” Wasmann Jour. Biol., Vol.
21, No. 2, pp. 141-148, figs. la, 1b, 1963.

(627) See Cardita naviformis Reeve, Reeve, Conch. Icon., Vol. 1,
Cardita, sp. 45, pl. 9, fig. 45, 1843. “Hab. Valparaiso, South
America (dredged from sandy mud at the depth of twenty-five
fathoms); Cuming.”

(628) Paraglans Chavan, Jour. de Conchyl., Vol. 84, No. 1, p. 97,
July 31, 1941. “Type désigné: ‘Cardium’ (Cardita) calcitrapoides
Lamarck, 1806 (Ann. du Museum, tomes VII et IX, PI. 20, fig. 8;
Mém. foss. Paris, p. 208, Pl. 18, fig. 8), du Lutétien de Grignon.”
(629) Woodring, W. P., Bramlette, M. N., and Kew, W.S. W.,
U.S.G.S., Prof. Paper 207, p. 82, 1946.

(630) Orcutt, C. R., West Amer. Sci., Vol. 6, Whole No. 45, p. 70,
July, 1889.

(631) Pteromeris Conrad, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 14, p. 290, 1862. Type (by original designation): Cardita per-
plana Conrad. See Gardner, J., U.S.G.S., Prof. Paper 199, p. 72,
pl. 13, figs. 6-9, 1948. Late Miocene to Recent on Atlantic coast of
United States.

(632) See Iredale, T., Proc. Malacol. Soc. London, Vol. 11, Pt. 3,
p. 177, September, 1914.

(633) Coripia de Gregorio, Bull. Soc. Malacol. Ital., Vol. 10, p.
153, 1884 (1885). Type (designated by Fischer, Man. de Conchyl.,
p. 1187, 1887): Cardita corbis Philippi.

(634) See Woodring, W. P., in Woodring, W. P., and Bramlette,
M.N., U.S.G.S., Prof. Paper 222, pp. 65, 86, 1950.

(635) Venericardia yatesi Arnold, Smithsonian Miscell. Coll.,
(Quarterly Issue), Vol. 50, Pt. 4, p. 21, pl. 58, figs. 2a, 2b, Decem-
ber 13, 1907. “Bath-house Beach, Santa Barbara, California.”

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

“Fernando formation (Pliocene or lower Pleistocene).”

(636) See Cardita (Miodontiscus) prolongata Carpenter,
Slodkewitsch, Acad. Sci. USSR, Paleontology of USSR, Vol. 10,
Pt. 1, Fase. 18, p. 336, 1938; Fase. 19, p. 146, pl. 66, figs. 5, 6, 7, 8, 9,
1938. Kavran series, Pliocene.

(637) See Pleshakov, I. B., Trans. Geol. Oil Inst., Ser. A, Fase.
123, p. 31, 1939.

(638) Cardita (Miodontiscus) nakamurai annakensis Oinomi-
kado, Trans. Proc. Palaeo. Soc. Japan, Vol. 18, Nos. 11-12 (Jour.
Geol. Soc. Japan, Vol. 45), p. 90 (674), pl. 20 (7), figs. 7, 8, 1938.
Annaka-mati, Usui-gun, Neogene. [Miocene, according to Hatai
and Nisiyama, 1952.]

(639) See Milneria cf. M. kelseyi Dall, Vedder, U.S.G.S., Prof.
Paper 400B, p. 326, 1960.

(640) See Vedder, J. G., in Vedder, J. G., and Norris, R. M.,
U.S.G.S., Prof. Paper 369, p. 46, 1963.

(641) Milneria kelseyi Dall, Proc. U.S. Nat. Mus., Vol. 52, No.
2183, p. 408, December 27, 1916. “On Haliotis shells, Central
California.” Illustrated by Dall in Orcutt, Proc. U.S. Nat. Mus.,
Vol. 8, No. 35, pl. 24, figs. 4, 7, September 30, 1885.—I. S. Oldroyd,
Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 117, pl. 54,
figs. 19-23, 1924. ‘Monterey Bay, California, to Point Abreojos,
Lower California.”—Abbott, Amer. Sea Shells (D. Van Nostrand
Co., Inc.: New York; London) p. 380, fig. 76 (a-c), 1954. [We find
no reason to interpret Dall’s description of M. kelseyi other than
as given by Dall. In this connection see remarks by F. Baker,
Nautilus, Vol. 50, No. 3, p. 86, 1937.]

(642) ‘Superfamily Leptonacea” was cited by Dall, in Trans.
Wagner Free Inst. Sci., Vol. 3, Pt. 3, p. 546, 1895. “Fam. XII.
Leptonidae” was cited by Gray, Proce. Zool. Soe. London for 1847,
p. 193. Bowden and Heppell (Journ. Conch., Vol. 26, No. 4, pp.
245, 264, 1968) refer this superfamily to the Galeommatacea.
(643) Dall, W. H., “Synopsis of the Recent and Tertiary Lepto-
nacea of North America and the West Indies,” Proc. U.S. Nat.
Mus., Vol. 21, No. 1177, pp. 873-897, pls. 87-88, June 26, 1899. See
also Dall, W. H., Trans. Wagner Free Inst. Sci., Vol. 3, Pt. 5, pp.
1117-1119, pls. 44-45, December, 1900.

(644) Laseron, C. L., “A Revision of the New South Wales Lep-
tonidae, Mollusca: Pelecypoda,” Rec. Australian Mus., Vol. 24,
No. 2, pp. 7-21, figs. 1-27, November 23, 1956.

(645) Cited as Family Erycinidae by Deshayes, Traité Elément.
Conchyl., Vol. 1, Pt. 2, p. 718, 1839.

(646) See Swainson, W., Zool. Illustr., Ser. 2, Vol. 3, p. 111 and
index, 1832-1833.

(647) See Wood, S., Palaeontogr. Soc. London, Vol. 27, Suppl.
Crag Moll., Pt. 2, Bivalvia, p. 120, for 1873 (issued February,
1874).

(648) Chavan, A., “Remarques sur la charniére des Erycinacea
et des Cyamiacea,” Bull. Soc. Géol. France, Sér. 7, Tom. 1, No. 7,
pp. 712-718, figs. 1 (A-K), 2 (A-C), 1959, issued June, 1960.

(649) See Popham, M. L., “The mantle cavity of some of the
Erycinidae, Montacutidae and Galeommatidae with special ref-
erence to the ciliary mechanisms,” Jour. Mar. Biol. Assoc. U. K.,
Vol. 24, No. 2, pp. 549-587, figs. 1-26 in text, August, 1940.

(650) Oldfield, E., “The reproduction and development of some
members of the Erycinidae and Montacutidae (Mollusca, Eu-
lamellibranchiata),”’ Proc. Malacol. Soe. London, Vol. 36, Pt. 2,
pp. 79-120, figs. 1-21 in text, August, 1964.

(651) See Boss, K. J., “Symbiotic Erycinacean bivalves,’ Ma-
lacologia, Vol. 3, No. 2, pp. 183-195, November, 1965.

(652) Lepton Turton, Conchyl. Insul. Brit., (Conchylia-Dithyra.
21), p. 61, 1822. Type species (designated by Gray, Proc. Zool.
Soc. London for 1847, p. 193): “Mactra sp. Montag. Mactra
squamosa.” [ = Solen squamosus Montagu, Test. Brit. Pt. 2, p.
565, 1803. “Salcomb bay.” Illustrated by Turton, pl. 6, figs. 1, 2, 3;
by Forbes and Hanley, Vol. 4 (plates), pl. 36, figs. 8, 9, 1849; pl. O,
fig. 6 (animal), 1848; by Buequoy, Dautzenberg, and Dollfus,
1892, Vol. 2, Fase. 6 (Pelecypoda Fase. 19), pl. 39, figs. 7, 8, 9,

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

1892]. Stoliezka (1870, Vol. 3, pp. XIX, 265) also designated as
type, “Type, Lept. squamosum, Mont. sp.”

(653) Cited as Family Kelliadae by Forbes and Hanley, Hist.
Brit. Moll., Vol. 2, p. 69, 1849; also by Clark, Ann. Mag. Nat.
Hist., Ser. 2, Vol. 7, No. 42, p. 471, 1851; as Family Kelliidae by
Tate, Append. to Man. Moll. by Woodward, p. 73, 1868.

(654) Spaniodon Reuss, Sitz, K. K. Akad. Wiss. Wien, Bd. 55,
Heft 1, p. 134, 1867. Sole species, S. nitidus Reuss, p. 135, pl. 8,
fig. 3, “Steinsalzablagerung von Wieliczka in Galizien.” Miocene.
(Not Spaniodon Pictet, 1851. Pisces). Renamed Spaniodontella
by Andrussow, Verhandl. Russ. -Kais. Min. Gesell. zu Peters-
burg, Ser. 2, Bd. 48, p. 275, 1912. Miocene.

(655) See Cossmann, M., and Peyrot, A., Actes Soc. Linn. Bor-
deaux, Tom. 65 (Conch. Néogén. de L’Aquitaine, Tome 1, Livr. 3),
p. 595 (footnote), 1911 (1912).

(656) Spaniorinus Dall, Proc. Proc. U.S. Nat. Mus., Vol. 21, No.
1177, p. 875, June, 1899. Sole species, “SS. cossmanni Dall.” This
species was described and illustrated in Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 5, p. 1125, pl. 45, figs. 27, 27a, December,
1900. “Miocene of Petersburg, Virginia; Burns.” [Description of
Spaniorinus, p. 1123.]

(657) Harry, W. W., “A Review of the living species of Ali-
gena,” Veliger, Vol. 11, No. 3, pp. 164-181, figs. 1-40, January 1,
1969.

(658) See Aligena aequata var. nuda Dall, Glen, Maryland Geol.
Surv., Miocene, p. 333, pl. 89, fig. 4, 1904. “Calvert Formation.
Plum Point,” Maryland.

(659) Aligena laevis H. C. Lea, Trans. Amer. Philos. Soc., Ser. 2,
Vol. 9, p. 238, pl. 14, fig. 14, December, 1846. “From the Tertiary
of Petersburg, Virginia.”—Gardner, U.S.G.S., Prof. Paper 199-A,
p. 87 (in text), pl. 14, figs. 24-26, 1943.

(660) Aligena redondoensis T. Burch, Nautilus, Vol. 55, No. 2, p.
50, pl. 4, figs. 5, 6, 7a-c, October 24, 1941. “Burch station 3833 in
75 fathoms off Redondo Beach, California, about latitude
38°38'50”, longitude 118°26’30’.” See also Min. Conch. Club South.
Calif., No. 40, p. 28, 4 figs., October, 1944. Redondo Beach, La
Jolla, and Santa Rosa Island, California.

(661) Aligena (Odontogena) borealis Cowan, Veliger, Vol. 7, No.
2, p. 108, pl. 20, figs. 1 and 2, October 1, 1964. “Type locality: The
northern part of Georgia Strait, British Columbia, Canada, at
49°15’ North latitude and 124°15’ West longitude. Depth 190
fathoms at Cowan Station 724.”

(662) See remarks by Lynge, H., Kgl. Danske Vid. Selsk. Skr.,
Raek. 7, Nat. og Math. Afd., Vol. 5, No. 3, p. 178 (82), 1909. Also
Dell, R. K., Discovery Repts., Vol. 38, p. 212, 1964.

(663) See Chace, E. P., Nautilus, Vol. 56, No. 2, p. 42, 1942.

(664) See Oldfield, E., “The functional morphology of Kellia su-
borbicularis (Montagu), Montacuta ferruginosa (Montagu) and
M. substriata (Montagu), (Mollusca, Lamellibranchiata),” Proc.
Malacol. Soe. London, Vol. 34, Pt. 5, pp. 255-295, figs. 1-11, Au-
gust 1961.

(665) For partial synonymy, see p. 000.

(666) See Soper, E. K., and Grant, U. S., IV, Bull. Geol. Soe.
Amer., Vol. 43, No. 4, p. 1057, 1932.

(667) See Laws, C. R., Trans. Proc. Roy. Soc. New Zealand, Vol.
66, Pt. 1, p. 53, 1936. Waitotaran faunule, Kaawa Creek.

(668) See Smith, E. A., Proce. Malacol. Soe. London, Vol. 5, p. 163,
1902. Concerning this problem of relationship see also Morch
(Malakozool. Blatter, Bd. 7, p. 200, 1861), and von Ihering (An.
Mus. Nae. Buenos Aires, Vol. 14, Ser. 3, Vol. 7, p. 552, 1907.)

(669) See Soot-Ryen, T., Sci. Res. Norwegian Antarctic Exped.
1927-1928, et seq., No. 32, p. 31, 1951.

(670) See Kellia laperousii chironii Carpenter, K. V. W.
Palmer, Geol. Soc. Amer., Mem. 76, pl. 9, figs. 6-10, 1958. ‘““Neah
Bay, Washington (type). Also cited from San Francisco and
San Diego, California.

(671) See Palmer, K. V. W., 1958, p. 88.

(672) Bornia (Temblornia) keenae Marks, Bull. Amer. Paleo.,

363

Vol. 33, No. 139, p. 341 (71), pl. 46 (4), fig. 3, December 20, 1951.
“Subibaja formation, Lower Miocene of Ecuador.”

(673) Cited as family Montacutidae by Clark (Hist. Brit. Mar.
Test. Moll., London), pp. 5, 94, 1855.

(674) See Morrison, J. P. E., ‘“Rochefortia—A new record in
Tampa Bay.” Ann. Repts. Amer. Malacol. Union for 1962, p. 14.—
Keen, 1969, p. N531.

(675) See Dell, R. K., Discovery Repts., Vol. 33, p. 213, 1964.
(676) See Woodring, W. P., in Woodring, W. P., and Bramlette,
M.N., U.S.G.S., Prof. Paper 222, pp. 65, 87, 1950.

(677) Mysella pedroana Dall, Proce. U.S. Nat. Mus., Vol. 21, No.
1177, p. 893, pl. 88, fig. 4, June, 1899. ““A single shell was found on
the beach at San Pedro.” California. See also T. and J. Q. Burch,
Min. Conch. Club South. California, No. 40, pp. 15, 16 (fig.,

“Venice, Calif.”’)

(678) Rochefortia golischi Dall, Proc. U.S. Nat. Mus., Vol. 52, No.
2183, p. 411, December 27, 1916. “Off Santa Rosa Island, Califor-
nia, in 13 fathoms.”

(679) See MacGinitie, Nettie, Min. Conch. Club South. Califor-
nia, No. 148, p. 6, June-July, 1955.

(680) Valentine, J. W., “Pleistocene Molluscan Notes. I. The Bay
Point formation at its type locality,” Jour. Paleo., Vol. 33, No. 4,
pp. 685-688, 1 fig. in text, 1959. (See p. 687.)

(681) Cited as Family Sportellidae by Dall, 1899.

(682) See Chavan, A., Bull. Soe. Géol. France, Sér. 7, Tom. 1, No.
7, p. 716, 1959 (June, 1960). [Chavan placed the family Sportel-
lidae in the superfamily Cyamiacea. |

(683) Lamy, E., “Note sur le genre Basterotia Mayer, 1859 [Mol-
lusques Lamellibranches],” Comp. Rend. Congrés des Soc. Sav-
antes, Paris, pp. 503-508, 1 fig. in text, 1925.

(684) See Basterotia (Basterotella) ecuadoriana Olsson, Mol-
lusks of the tropical eastern Pacific (Paleo. Res. Inst.: Ithaca,
New York), p. 243, pl. 36, figs. 8, 8a, March 10, 1961. “Manta,
Ecuador.” Recent.

(685) See Anisodonta peninsulare E. K. Jordan, Contrib. Dept.
Geol. Stanford Univ., Vol. 1, No. 4, p. 147, pl. 18, figs. 11, 12, No-
vember 13, 1936. ‘Magdalena Bay, Lower California; . . . Pleisto-
cene.

(686) See Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 31,
Pt. 4, p. 137, 1947.

(687) See Keen, A. M., Proc. Calif. Acad. Sci., Ser. 4, Vol. 30, No.
9, pp. 185, 194, 1964. Isla Espiritu Santo, Gulf of California.
(688) Basterotia californica Durham, Geol. Soc. Amer., Mem.
43, Pt. 2, p. 94, pl. 25, figs. 9, 18, August 10, 1950. Loe. A3582 (UC),
“Pleistocene, Santa Inez Bay, Lower California. From 20-foot
terrace level extending from loc. 3581 to beach.”

(689) Cited as Lucinacea by Anton, Verzeich. Conchyl., p. 6,
1839.

(690) See Allen, J. A. ‘On the basic Form and Adaptation to
Habitat in the Lucinacea (Eulamellibranchia),”’ Philos. Trans.
Roy. Soc. (London), Ser. B, Vol. 241, pp. 421-484, pl. 18, 1958.
(691) Cited as family Lucinadae by Fleming in 1828; as family
Lucinidae by d’Orbigny, 1839; as family Lucineae by Deshayes,
1839; and as family Lucinidae by Gray, 1840.

(692) See Cox, L. R., Proc. Malacol. Soc. London, Vol. 24, Pt. 4, p.
137, 1941. See also pl. 8, fig. 1 (Phacoides megameris Dall).

(693) Chavan, A., ‘Essai Critique de Classification des Lucines,”
Jour. de Conchyl., Vol. 81, No. 2, pp. 133-153, fig. 1, June 10, 1937;
Vol. 81, No. 3, pp. 198-216, figs. 2-5, August 10, 1937; Vol. 81, No.
4, pp. 237-282, figs. 6-10, December 1, 1937; Vol. 82, No. 1, pp. 59-
97, figs. 11-18, March 25, 1938; Vol. 82, No. 2, pp. 105-130, figs. 14-
16, May 25, 1938. See also ‘‘Nomenclatural Notes on carditids and
lucinids,” Jour. Washington Acad. Sci., Vol. 42, No. 4, pp. 116-
122, April 15, 1952; “Remarques sur l’origine des Lucinacea (mol-
lusques pélécypodes),” Compt. Rend. Somm. Séane. Soc. Géol.
France for 1966, No. 4, pp. 163-164, 1966.

(694) Lamy, E., “Révision des Lucinacea vivants du Muséum
d'Histoire Naturelle de Paris,” Jour. de Conchyl., Vol. 65, No. 1,

364

pp. 71-122, figs., July 25, 1920; No. 2, pp. 169-222, figs., November
20, 1920; No. 3, pp. 233-284, figs., June 20, 1921.

(695) See Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 31,
Pt. 3, pp. 111-120, December 5, 1946. See also Keen, A. M., Sea
Shells of Tropical West America (Stanford Univ. Press: Stan-
ford, California), pp. 92-101, 1958; Olsson, A. A., Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York),
pp. 206-222, 1961.

(696) Not represented in the present collections.

(697) See Lucina (Here) aragoensis Turner, Geol. Soc. Amer.,
Spec. Papers No. 10, p. 51, pl. 9, figs. 4, 5, June 1, 1938, and Lucina
(Here) taffana (Dickerson), Vokes, Ann. New York Acad. Sci.,
Vol. 38, p. 71, pl. 10, figs. 1, 2, 3, 5, 1939.

(698) Chavan, A., Jour. de Conchyl., Vol. 81, No. 2, p. 146, 1937.
Genotype of Linga, Lucina columbella Lamarck (illustrated in
fig. 1, p. 145).

(699) Linga de Gregorio, Bull. Soe. Malacol. Ital., Vol. 10, p. 217,
1884. Several species cited including Lucina columbella
Lamarck.—Woodring, Carnegie Inst. Washington, Publ. 366, p.
118, 1925. Type, Lucina columbella Lamarck.

(700) Jllesca Olsson, Bull. Amer. Paleo., Vol. 19, No. 68, p. 90,
June 30, 1932. “Type.—Phacoides (Here) andersoni Olsson.” Il-
lustrated on pl. 7, fig. 7. Basal Talara formation at Yasila, Peru,
Miocene.

(701) See Wagner, C. M., and Schilling, K. H., Univ. Calif. Publ.
Bull. Dept. Geol. Sci., Vol. 14, No. 6, p. 244, 1923.

(702) Lamy, E., Jour. de Conchyl., Vol. 65, No. 2, pp. 202, 208,
1920.

(703) See d’Orbigny, A., Prod. Paleo., Vol. 2, p. 241, 1850.

(704) Cytherea excavata Morton, Amer. Jour. Sci., Ser. 1, Vol.
23, No. 2, p. 292, pl. 5, fig. 1, 1833.

(705) Lucina (Here) excavata Carpenter temblorensis Adegoke,
Univ. Calif. Publ. Geol. Sci., Vol. 80, p. 115, pl. 4, figs. 8, 11, 12,
September 25, 1969.

(706) See Chavan, A., Jour. de Conchyl., Vol. 81, No. 3, p. 240,
fig. 6, 1937.

(707) See Durham, J. W., Geol. Soc. Amer., Mem. 43, Pt. 2, p. 77,
1950.

(708) Myra Keen mentioned that the record of occurrence by
Loel and Corey (Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 22,
No. 3, p. 210, 1932) might be referable to Lucinisca menuda
Keen (Trans. San Diego Soc. Nat. Hist., Vol. 10, No. 2, p. 40, pl. 3,
figs. 15, 16, December 30, 1943. Round Mountain silt (Temblor),
Miocene of California.)

(709) Phacoides (Lucinisca) nuttallii Conrad, var. centrifugus
Dall, Proc. U.S. Nat. Mus., Vol. 23, No. 1237, p. 812, pl. 39, fig. 18,
August 22, 1901. “Dredged in the Gulf in 25 fathoms.” “Gulf of
California.”

(710) Phacoides (Lucinisca) liana Pilsbry, Proc. Acad. Nat. Sci.
Philadelphia, Vol. 88, p. 435, pl. 41, fig. 8, November 138, 1931.
“Panama Bay, a mile out in 10-40 feet.”

(711) Lucina (Myrtea) nuttallii Conrad, Nomura, Saito Ho-On
Kai Mus., Res. Bull., No. 6, p. 211, pl. 17(2), fig. 1, September,
1935. Siogama, Northeast Honsyd, Japan. Miocene.

(712) Lucina yokoyamai Otuka, Bull. Earthquake Res. Inst.,
Vol. 12, Pt. 3, p. 615, pl. 47, figs. 29, 31, 32, Sept. 30, 1934. Shiratori
Miocene. Nisatai.

(713) Hirayama, K., ‘On some Miocene species of Lucinoma
from Japan, with description of two new species,” Jap. Jour.
Geol. Geogr., Vol. 25, Nos. 1-2, pp. 101-115, pls. 10, 11, October 31,
1954.

(714) Myrtea (Lucinoma) taylori Powell, Rec. Auckland Inst.
Mus., Vol. 1, No. 6, p. 331, pl. 76, fig. 3, September 26, 1935. ‘Lo-
cality: Motutara (A and B).” Awamoan, early Miocene.

(715) Lucinoma marwicki Dell, Ree. Dominion Mus., Vol. 2, Pt.
1, p. 39, figs. 4, 11, October, 1953. Chatham Rise, 45°48’S.,
178°58’ W., in 361 meters.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(716) See Lucinoma galatheae cited by Lemche (Galathea Deep
Sea Exped.), p. 130, fig., 1956. “in Milford Sound on the west of
South Island, New Zealand.”

(717) Lucina (Lucinoma) chiripanica Olsson, Bull. Amer.
Paleo., Vol. 27, No. 106, p. 188 (36), pl. 17 (4), figs. 1, 4, December
25, 1942. ‘‘Charco Azul.”’ Panama. Pliocene.

(718) See Lucina borealis Linnaeus, Melvill and Standen, Proc.
Zool. Soc. London, for 1906, p. 814. Persian Gulf.

(719) Thiele, J., and Jaeckel, S., Wissenschaft. Ergeb. d. Deuts-
chen Tiefsee-Exped., Bd. 21, Heft 1, p. 220 (62), 1931.

(720) Alucinoma Habe, “Descriptions of Four New Bivalves
from Japan.” Venus, Vol. 19, Nos. 3-4, p. 181, February, 1958.
Sole species: Alucinoma soyoae Habe, p. 181, text figs. 5, 6.
“Type locality: Soyo-maru Station No. 498 (between Oki Islands
and Shimane Peninsula, Honshu, in the Japan Sea, 139 m. in
depth).”

(721) Lucina acutilineata Conrad, U.S. Explor. Exped.
(Wilkes), Vol. 10, Geol., p. 725, pl. 18, figs. 2, 2a, 2b, 1849.—Weaver,
Univ. Washington Publ. Geol., Vol. 5, Pt. 1, p. 143, pl. 34, figs. 8
and 11 (holotype), 16, 1942 [Issued December 31, 1943]. See also
Moore, E. J., U.S.G.S., Prof. Paper 419, p. 70, pl. 15, figs. 7-10, 12,
1963.

(722) See Stewart, R. B., in Tegland, N. M., Univ. Calif. Publ.
Bull. Dept. Geol. Sci., Vol. 23, No. 3, p. 116, 1933.

(723) Woodring, W. P., U.S.G.S., Prof. Paper 190, p. 52, 1938.
See also remarks by E. J. Moore, U.S.G.S., Prof. Paper 419, p. 70,
1963.

(724) Dall, W. H., U.S.G.S., Prof. Paper 59, p. 117, pl. 12, fig. 6,
1909.

(725) Lucinoma annulata densilirata Dall, Proc. Biol. Soe.
Washington, Vol. 32, p. 249, December 31, 1919. “Harbor of
Sitka, Alaska, at station 92, in ten fathoms, mud and shell, W. H.
Dall.” Also cited as Lucinoma annulata densilineata (Dall, 1921,
p. 35).

(726) Phacoides columbianum Clark and Arnold, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 5, p. 144, pl. 25, figs. 2a,
2b, November 6, 1923. Loc. 231 (CAS), “In the sea cliffs east of
the mouth of Kirby Creek, 6 miles west of Sooke, Vancouver Is-
land.” [Late Oligocene or early Miocene. }

(727) Phacoides (Lucinoma) hannibali Clark, Univ. Calif. Publ.
Bull. Dept. Geol. Sci., Vol. 15, No. 4, p. 89, pl. 22, figs. 2, 4, Janu-
ary 5, 1925. According to Tegland (same journal, Vol. 28, No. 3, p.
115, pl. 8, figs. 5, 6, 7, 8, 9, 10, 11, 12, 18, 1933) the type specimen
of L. hannibali “came from the Twin Rivers Oligocene shales,
N.P. Loe. 120. west of West Twin River, Washington.”

(728) See Kuroda, T., and Habe, T., Check List and Bibliogra-
phy of the Recent Marine Mollusca of Japan, p. 23, 1952. See
also, Yamamoto and Habe, Bull. Biol. Sta. Asamushi, Tohoku
Univ., Vol. 9, No. 3, p. 90, pl. 6, figs. 24, 25, 1959. Recent.—Hatai,
Masuda, and Suzuki, Saito Ho-on Kai Mus., Res. Bull. No. 30, p.
32, pl. 1, figs. 28a, b, 1962. Pliocene.

(729) Callucina Dall, Proc. U.S. Nat. Mus., Vol. 23, No. 1237, p.
806, August 22, 1901. “Type, Lucina radians Conrad.” Illus-
trated by Dall, pl. 42, fig. 8. Also by Conrad, Fossils of Medial
Tertiary of the United States, (Republication by Wagner Free
Inst. Sci., 1893), p. 96 (70), pl. 40, fig. 3.—Olsson and Harbison,
Acad. Nat. Sci. Philadelphia, Monogr. No. 8, p. 85, pl. 7, fig. 3,
1953.

(730) See Eyerdam, W., Nautilus, Vol. 51, No. 3, p. 100, January,
1938.

(731) See Chavan, A., Jour. de Conchyl., Vol. 81, No. 4, p. 274,
fig. 10, 1937.

(732) Lucina (Myrtea) nipponica Nomura and Hatai, Saito Ho-
On Kai Mus., Res. Bull. No. 10, p. 123, pl. 15, figs. 12a, 12b, Au-
gust, 1936. From “Okada,” Tanagura beds, northeast Honsyd,
Japan, middle Miocene.

(733) Gale, H. R., in Preston, H. M., Ann. Rept. State Oil and

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Gas Supervisor. Summ. Oper. Calif. Oil Fields, Vol. 16, No. 4, p.
15, April, May, June, 1931 (1932).

(734) Callucinella Chavan, Cahiers Géol., Ann. 1960, Nos. 58-61,
p. 561, 1961. “Type: Lucina albella Lamarck, 1806 (Ann. Mus., 7,
p. 240, no. 8; 1808, ibid., 12, pl. 42, fig. 6a, b).”

(735) For references concerning this species see page 000

(736) Phacoides (Parvilucina) approximata Dall, Proce. U.S.
Nat. Mus., Vol. 23, No. 1237, pp. 813, 828, pl. 39, fig. 4, August 22,
1901. ‘From the Gulf of California, in 26 fathoms, sand.”’ See
also Hertlein and Strong, Zoologica, Vol. 31, Pt. 3, p. 115, 1946.—
Keen, Sea Shells of Tropical West America (Stanford Univ.
Press: Stanford, California), p. 96, fig. 192, 1958.

(737) Pseudomiltha Fischer, Man. de Conchyl., Fase. 11, p. 1144,
1887. Sole species, Lucina gigantea Deshayes (Descript. Coq.
Foss. Paris, Vol. 1, p. 91, pl. 15, figs. 11, 12, 1824).

(738) Eomiltha Cossmann, in Cossmann and Peyrot, Act. Soe.
Linn. Bordeaux, Vol. 65, (Conch. Néog. de L’Aquitaine, Livr. 3),
p- 650, 1911 [May 15, 1912.] Type (by original designation): Lu-
cina contorta Defrance (Dict. Sci. Nat., Vol. 27, p. 274, 1823.
See also Deshayes, Descript. Coq. Foss. Environs de Paris|Tome
1, Anim. s. Vert, découverts dans le Bassin de Paris, Tome 1, p.
645, 1860.

(739) Plastomiltha Stewart, Acad. Nat. Sci. Philadelphia, Spec.
Publ. No. 3, pp. 38, 191, 1930. Type (by original designation):
Cyclas claibornensis Conrad (Amer. Jour. Conch., Vol. 1, p. 146,
1865). Illustrated by Harris, Bull. Amer. Paleo., Vol. 6, Bull. 31,
p. 121, pl. 39, figs. 8, 9, 1919.

(740) Armimiltha Olsson and Harbison, Acad. Nat. Sci. Phila-
delphia, Monogr. No. 8, p. 84, November 6, 1953. Type (by origi-
nal designation): Lucina disciformis Heilprin (Trans. Wagner
Free Inst. Sci., Vol. 1, p. 94, pl. 11, fig. 28, 1887). See also Olsson
and Harbison, 1953, p. 84, pl. 7, figs. 1, la, 1b. St Petersburg and
Caloosahatchee, Florida, Pliocene.

(741) See Wilkins, R. W. T., “Miltha in the south-eastern Aus-
tralian Tertiary,” Jour. Malacol. Soc. Australia, No. 6, pp. 43-49,
pl. 5, 1 fig. in text, December 31, 1962.

(742) Vokes, H. E., “Observations on the genus Miltha (Mol-
lusea: Bivalvia) with notes on the type and the Florida Neogene
species,” Tulane Studies Geol. Paleo., Vol. 7, No. 3, pp. 93-126,
pls. 1-7, text figs. 1-8, December 29, 1969.

(743) See Phacoides (Miltha) sanctaecrucis Arnold, Khomenko,
Trans. Geol. Oil Inst., Ser. A, Fase. 103, pp. 48, 66, pl. 8, fig. 2; pl.
9, fig. 5, 1938.

(744) See Stanton, R. J., Jr., Jour. Paleo., Vol. 40, No. 1, p. 23,
1966. “Miltha ef. M. xantusi,” reported by Addicott and Vedder
from the Santa Margarita Formation of late Miocene age, at
Comanche Point; Kern Co., California (U.S.G.S., Prof. Paper No.
475C, p. C67, 1968).

(745) P[hacoides]. joannis Dall, Nautilus, Vol. 18, No. 10, p. 112,
February, 1905. “Pliocene, ... of San Juan, Lower California,
(opposite Guaymas).”

(746) Phacoides (Miltha) sanctaecrucis Arnold, U.S.G.S., Bull.
396, p. 57, pl. 6, fig. 6, 1909 (January 15, 1910). “United States Ge-
ological Survey locality 4861, sec. 28, T. 25 S., R. 18 E., in ‘reef
bed’ one-fourth mile southeast of Barton’s cabin, Devil’s Den
district, Kern County,” California. ‘Lower Miocene.”

(747) Stoliczka, F., Mem. Geol. Sur. India, Palaeont. Indica, Ser.
6, Cret. Fauna of Southern India, Vol. 3, p. 252, 1871.

(748) See Lucina sanctae-crucis Pictet and Campiche, Mater.
pour la Palaeo. Suisse, Ser. 4, p. 289, p. 122, figs. 8, 8a, 8b, 1864-
1867. “Gisement a Sainte-Croix. Le Gault inférieur, 0 elle est
abondante.”

(749) Miltha pacifica Olsson, Bull. Amer. Paleo., Vol. 19, No. 68,
p. 98, pl. 7, figs. 3, 4, 5, June 30, 1982. “Montera formation, Lu-
cina zone, Que. Montera near Bayovar.” Peru. Miocene.

(750) Miltha theringiana Doello-Jurado, Physis, Rey. Soc. Ar-
gentina Cienc. Nat., Vol. 4, No. 18, p. 558, 2 figs. (p. 559), Decem-
ber 31, 1919. “Diamante (prov. d’Entre Rios).” “formation

365

entrerrienne (probablement Miocéne).”

(751) Miltha neozelanica Marshall and Murdock, Trans. Proc.
New Zealand Institute, Vol. 53, p. 78, pl. 16, figs. 1, 2; pl. 17, fig. 1,
August 31, 1921 (issued separately June 27, 1921). “On the coast
about three miles north of the Waipipi Stream, in brown sands
and in blue sandy clay; also in the seacliff near to the Hawera
County metal-pit, Whakina.” Late Tertiary.

(752) Milthoidea Marwick, Geol. Surv. New Zealand, Palaeo.
Bull. No. 13, p. 70, 1931. Type: Miltha neozealanica Marshall and
Murdock.

(753) Ludbrook, N. H., Trans. Roy. Soc. South Australia, Vol. 78,
p. 54, 1955.

(754) See Phacoides xantusi Dall, Hanna, Proc. Calif. Acad. Sci.,
Ser. 4, Vol. 14, No. 18, p. 474, pl. 28, fig. 7; pl. 29, fig. 1, 1926.

(755) Jordan, E. K., Contrib. Dept. Geol. Stanford Univ., Vol. 1,
No. 4, p. 112, 1936.

(756) Smith, J. P., Proc. Calif. Acad. Sci., Ser. 4, Vol. 9, No. 4, pp.
137, 167, 1919.

57) Cited as family Diplodontidae by Dall, Trans. Wagner

ree Inst. Sci., Vol. 3, Pt. 3, p. 545, March, 1895. Also cited as

imily Ungulinidae by H. and A. Adams, 1857.

58) Chavan, A., “Essai Critique de Classification des Unguli-
nidae,” Bull. Inst. Roy. Sci. Nat. Belgique, Tome 38, No. 23, pp. 1-
23, figs. 1-14 in text, July, 1962.

(759) See Lamy, E., Jour. de Conchyl., Vol. 65, No. 4, pp. 335-377,
June 20, 1921. See also Olsson, 1961, pp. 201-206.

(760) Prashad, B., Siboga Exped., Mon. 53c, p. 164, 1932.

(761) Chavan, A., Jour. Washington Acad. Sci., Vol. 42, No. 4,
pp. 121-122, 1952.

(762) From Hertlein, L. G., and Strong, A. M., Zoologica, Vol.
31, Pt. 4, p. 130, 1947.

(763) See Chavan, A., Bull. Inst. Roy. Sci. Nat. Belgique, Tome
38, No. 28, p. 16 (in text), 1962.

(764) Timothynus Harris and Palmer, Bull. Amer. Paleo., Vol.
30, No. 117 (first section), p. 86, August 3, 1946. “Type.—Sphae-
rella bulla Conrad, Amer. Jour. Conch., Vol. 1, 1865, p. 188, pl. 10,
fig. 9.” See also Harris and Palmer, pl. 19, figs. 12-16. Jackson,
Eocene.

(765) See Haas, F., Field Mus. Nat. Hist., Zool. Ser., Vol. 29, No.
1, pp. 8-12, figs. 3-6, 1943.

(766) Effinger, W. L., Jour. Paleo., Vol. 12, No. 4, p. 369, pl. 45,
figs. 11, 12, July, 1938. Gries Ranch, western Washington, Middle
Oligocene.

(767) Loel, W., and Corey, W. H., Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 22, No. 3, pp. 143, 168, 213, pl. 36, figs. 8a, 8b, 9,
1932.

(768) Bremner, C. St. J., Santa Barbara Mus. Nat. Hist., Oce.
Papers No. 1, p. 20, 1932.

(769) Khomenko, I. P., Trans. Geol. Oil Inst., Ser. A, Fase. 103,
p. 42, pl. 9, figs. 3, 4, 1938. See also Slodkewitsch, Paleo. USSR,
Vol. 10, Fase. 19, p. 150, pl. 73, figs. 2, 2a, 3, 3a, 1938.

(770) Diplodonta impolita Berry, Trans. San Diego Soc. Nat.
Hist., Vol. 11, No. 16, p. 409, pl. 28, figs. 3, 4, text fig. 2, Septem-
ber 1, 1953. ‘15 fathoms off Forrester Id., Alaska.”

(771) See Ranson, G., Jour. de Conchyl., Vol. 99, No. 2, p. 71,
1959. “La Plaine cotiére soulevée de Guadalupito,” Peru.

(772) Loripes parilis Conrad, Amer. Jour. Sci., Ser. 2, Vol. 5, No.
XV, p. 482, fig. 7, May, 1848. “Tertiary deposits on the Columbia
River, near Astoria.”” Oregon. Reprint by Dall, U.S.G.S., Prof.
Paper 59, p. 151, fig. 7, 1909. See also, p. 117, pl. 11, fig. 6.—
Weaver, Univ. Washington Publ. Geol., Vol. 5, p. 149, pl. 35, fig.
6, pl. 36, fig. 4, 1942 (issued Dec. 31, 1943) (as Taras parilis).
Middle Miocene at Astoria, Oregon. Also Coos Bay, Oregon,
Pliocene. See also Moore, E. J., U.S.G.S., Prof. Paper 419, p. 71,
pl. 28, fig. 9, 1963.

(773) See Etherington, T. J., Univ. Calif. Publ. Bull. Dept. Geol.
Sci., Vol. 20, No. 5, p. 76, pl. 5, figs. 4, 6, 1931.

(774) Lucina tellinoides Reeve, Conch. Icon., Vol. 6, Lucina,

366

species 56, pl. 9, fig. 56, June, 1850. “Hab. Isle of Muerte, Bay of
Guayaquil (in sandy mud at a depth of above eleven fathoms);
Cuming.”

(775) Diplodonta harfordi Anderson, Proc. Calif. Acad. Sci., Ser.
3, Vol. 2, No. 2, p. 197, pl. 17, figs. 88, 89, December 4, 1905. “This
shell occurs abundantly in the Coalinga Beds west of Coalinga.”
[Concerning the type locality see Keen, A. M., and Bentson, H.,
Geol. Soc. Amer., Spec. Papers No. 56, p. 47, 1944.]

(776) Diplodonta stephensoni Clark, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 11, No. 2, p. 139, pl. 12, fig. 6, July 16, 1918.

(777) Cited as family Thyasiridae by Dall, Trans. Wagner Free
Inst. Sci., Vol. 3, Pt. 5, p. 1116, 1900. Also cited as Cryptodontidae
by Dall, 1895.

(778) Adontorhina S. S. Berry, Bull. Amer. Paleo., Vol. 31, No.
127, p. 260(6), November 14, 1947. “Generitype.—Adontorhina
cyclica, new species.” Illustrated on pl. 26 (1), figs. 1, 2. “Lower
Pleistocene. ‘Hilltop Quarry,’ San Pedro, California.”

(779) See Clarke, A. H., Jr., Nat. Mus. Canada, Bull. No. 181, p.
65, 1962.

(780) Popenoe, W. P., in Emery, K. O., et al., Jour. Geol., Vol. 60,
No. 6, p. 524, November, 1952.

It is interesting to note that Thyasira disjuncta Gabb was re-
ported occurring in hard sandstone dredged on Cordell Bank
west of Point Reyes, California (see Hanna, G D., Proce. Calif.
Acad. Sci., Ser. 4, Vol. 27, No. 9, p. 3380 (footnote), 1952.

(781) See Hagg, R., Bull. Geol. Inst. Univ. Uppsala, Vol. 20, p.
46, pl. 4, figs. 14, 14a, 15, 16; pl. 5, figs. 18, 19, 19a, 20, 20a, 1925.
(782) See Dall, W. H., Proe. U.S. Nat. Mus., Vol. 23, No. 1237, pp.
784-791, August 22, 1901.

(783) Fleming, C. A., “New Zealand Recent Thyasiridae (Mol-
lusea),” Trans. Roy. Soc. New Zealand, Vol. 78, Pts. 2 and 3, pp.
251-254, pl. 25, August, 1950.

(784) See Soot-Ryen, T., “Thyasiridae” in “Antarctic Pelecy-
pods,” Norske Vidensk. Acad. Oslo, Sci. Res. Norwegian Antarct.
Exped., 1927-1928, et. seq., No. 32, pp. 30-31, 1951.

(785) Yabe, H., and Nomura, S., “Notes on the Recent and Ter-
tiary species of Thyasira from Japan,” Sci. Repts. Tohoku Im-
per. Univ., Sendai, Japan, 2nd Ser. (Geol.), Vol. 7, No. 4, pp. 88
(1)-95 (18), pls. 28 (1), 24 (2), 1925.

(786) Slodkewitsch, W. S., “Tertiary Peleeypoda from the Far
East,” Paleo. USSR, Vol. 10, Pt. 3, Fase. 18, pp. 339-352, 1938;
Fasc. 19, pp. 147-149, pls. 66-71, 1938.

(787) Kauffman, E. G., “Cretaceous Thyasira from the western
interior of North America,” Smithsonian Miscell. Coll., Vol. 152,
No. 1, Smithsonian Publ. 4695, pp. 1-159, pls. 1-5, figs. 1-18 in
text, June 30, 1967.

(788) See Odhner, N. H-j., (in Burch, J. Q.), Min. Conch. Club.
South. Calif., No. 39, p. 21, September, 1944.

(789) See Ockelmann, K. W., “The Status of Thyasira insignis,
T. plana and T. inaequalis, all Verrill and Bush,” Nautilus, Vol.
75, No. 2, pp. 50-55, October, 1961. (See especially pp. 52-54.)
(790) Cryptodon planus Verrill and Bush, Proe. U.S. Nat. Mus.,
Vol. 20, No. 1139, p. 788, pl. 88, figs. 3, 4, June 15, 1898. The type is
from U.S. Fish Comm. Station 254, “Cape Cod Bay, ‘Fishing
Ledge,’ Wood End Light N. 50° E. 7 miles” in 17 fathoms.

(791) Cryptodon (Axinulus) inequalis Verrill and Bush, Proc.
U.S. Nat. Mus., Vol. 20, No. 1139, p. 791, pl. 90, figs. 1, 2, June 15,
1898. The type is from U.S. Fish Comm. Stations 98-99, “Midway
between Sandwich Point and McNab’s Island Light, Halifax
Harbor,” in 18 fathoms. [See Rept. U.S. Comm. Fish and Fish-
eries, for 1886, issued 1889, p. 905. Dredgings by U.S. Str. Speed-
well, 1877.]

(792) See Eyerdam, W. J., Min. Conch. Club South. California,
No. 68, p. 16, April, 1947.

(793) Thyasira tokunagai Kuroda and Habe, Illust. Cat. Japa-
nese Shells, No. 18, p. 86, June 15, 1951. A new name for Thyas-
ira gouldii Philippi of Yabe and Nomura (Sci. Rept. Tohoku
Imper. Univ. Sendai, Japan, Ser. 2, Vol. 7, No. 4, p. 94, pl. 23, figs.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

6a, 6b, 1925. From “Shinagawa near Toky6.”)

(794) See Habe, T., Gen. Jap. Shells, Pelecypoda, No. 2, p. 126,
figs. 266, 267, 268, September, 1951.—Habe, Publ. Akkeshi Mar.
Biol. Sta., No. 4, p. 10, pl. 1, figs. 10, 11, 1955. Northern Honshu
and Hokkaido, Japan.

(795) Cryptodon marionensis E. A. Smith, Rept. Sci. Res. Voy.
Challenger, Zool., Vol. 13, Lamellibranchia, p. 194, pl. 14, figs. 6,
6a, 1885. ‘Prince Edward and Marion Islands, in 100 to 150 fath-
oms.”

(796) Woodring, W. P., (in Hoots, H. W.), U.S.G.S., Prof. Paper
165, p. 116, 1931.

(797) Soper, E. K., and Grant, U.S., IV, Bull. Geol. Soc. Amer.,
Vol. 43, p. 1060, 1932.

(798) Thyasira ef. T. gouldii Philippi, Woodring, in Woodring,
W. P., and Bramlette, M. N., U.S.G.S., Prof. Paper 222, pp. 65, 86,
1950.

(799) Richards, H., Trans. American Philos. Soc., new ser., Vol.
52, Pt. 3, p. 60, pl. 7, figs. 6, 7, 1962.

(800) See Valentine, J. W., Univ. Calif. Publ. Geol. Sci., Vol. 34,
No. 7, pp. 380, 338, 1961.

(801) Cryptodon barbarensis Dall, Proc. U.S. Nat. Mus., Vol. 12,
No. 778, p. 261, pl. 8, fig. 9, 1889 (issued March 7, 1890). “Hab.—
U.S. Fish Commission Station 240, off the Santa Barbara Is-
lands, California, in 276 fathoms, green mud.”—Dall, Proc. U.S.
Nat. Mus., Vol. 23, No. 1287, p. 790, 1901 (as Thyasira barbarensis).
“Coast of Washington, south to the Gulf of California, in 16 to
559 fathoms.”—I. S. Oldroyd, Stanford Univ. Publ. Univ. Ser.
Geol. Sci., Vol. 1, p. 120, pl. 53, fig. 3, 1924 (as Thyasira barba-
rensis). “Strait of Juan de Fuca to the Gulf of California.”—J. Q.
Burch (editor), Min. Conch. Club South. California, No. 39, p. 21,
September, 1944 (as Thyasira barbarensis). Range same as cited
by Dall.

(802) Axinus sarsii Philippi, Zeitschr. f. Malakozool., Jahrg. 2,
p. 91, June, 1845. “Lebend im norwegischen Meere.”’—G. O. Sars,
Bid. Kunsk. Norg. Arkt. Fauna. I. Moll. Reg. Arct. Norvegiae, p.
60, pl. 19, figs. 5a, 5b, 1878. From “Christiania-fjorden til Vad-
sopaa 60-300 F. D.” See also Lamy, Jour. de Conchyl., Vol. 65, No.
3, p. 296, 1921 (as Thyasira sarsii). Kara Sea, Bergen, and Bo-
husland, Norway. Also reported by others from Iceland, Green-
land and Spitzbergen. See also MacGinitie, Proc. U.S. Nat. Mus.,
Vol. 109, No. 3412, p. 171, pl. 4, fig. 12, 1959 (as Thyasira fleruosa
(Montagu, 1803) var. sars7). Pt. Barrow, Alaska, in 49 meters
(162 feet).

(803) See Dell, R. K., Discovery Repts., Vol. 33, p. 208, 1964.
(804) See Burch, J. Q. Min. Conch. Club South. California, No.
39, p. 22, 1944.

(805) See Axinopsis viridis Dall, Proc. U.S. Nat. Mus., Vol. 28,
No. 1287, p. 819, pl. 40, fig. 1, August 22, 1901."‘Iliuliuk, Alaska,
in 19 fathoms, mud.”

(806) See Willett, G., in Burch, J. Q., 1944, p. 22.

(807) See Axinopsis sericatus Carpenter, Willett, Bull. South.
California Acad. Sci., Vol. 45, Pt. 1, p. 29, 1946.

(808) See Avinopsida serricata Carpenter, Wagner, Geol. Surv.
Canada, Bull. 52, p. 6, pl. 1, figs. 14a, 14b, 1959. Lower Fraser
Valley and Vancouver Island, British Columbia.

(809) See Woodring, W. P., in Woodring, W. P., and Bramlette,
M.N., U.S.G.S., Prof. Paper No. 222, p. 86, 1950.

(810) Cited as “Familie” Cardiaceae” by Oken, 1818. Also cited
as ‘Les Cardiacées” by Lamarck, 1819; as Family Cardiacea by
Goldfuss, 1820; also by Schweigger, 1820 (as of Cuvier).

(811) Cited as Family Cardiadae by Gray, 1824.

(812) Keen, A. M., ‘“Nomenclatural units of the pelecypod fam-
ily Cardiidae,” Bull. Mus. Roy. Hist. Nat. Belgique, Tome 138, No.
7, pp. 1-22, 1987. See also, “Outline of a proposed classification of
the pelecypod family Cardiidae,” Min. Conch. Club South. Cali-
fornia, No. 111, pp. 6-8, July, 1951.

(813) Marwick, J., "New Zealand Fossil and Recent Cardiidae
(Mollusea),”” Trans. Roy. Soc. New Zealand, Vol. 74, Pt. 3, pp.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

255-272, pls. 35-37, December, 1944.

(814) Tremlett, W. E., “English Eocene and Oligocene Car-
diidae,” Proc. Malacol. Soc. London, Vol. 28, Pts. 4 and 5, pp. 115-
133, pls. 15-19, December 18, 1950.

(815) Sieber, R., “Die Mittelmiozinen Carditidae und Cardiidae
des Wiener Beckens,” Mitt. Geol. Gesell. Wien, Bd. 47, pp. 183-
234, pls. 1-3, 1 table, 1954 (1956).

(816) Dall, W. H., “Synopsis of the Family Cardiidae and of the
North American species,” Proc. U.S. Nat. Mus., Vol. 23, No. 1214,
pp. 381-392, 1900 (issued January, 1901).

(817) Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 31, Pt. 4,
pp. 138-148, pl. 1, February 21, 1947.

(818) Keen, A. M., Sea Shells of Tropical West America (Stan-
ford Univ. Press: Stanford, California), pp. 1-624, illustr., 1958.
(Cardiidae, pp. 114-121.)

(819) Olsson, A. A., Mollusks of the tropical eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), pp. 1-574, pls. 1-86, 1961.
(Cardiidae, pp. 243-257.)

(820) Burch, J. Q., et al., Min. Conch. Club South. Calif., No. 41,
pp. 21-27, November, 1944.

(821) McLean, R. A., “The Cardiidae of the Western Atlantic,”
Mem. Soc. Cubana Hist. Nat., Vol. 13, No. 3, pp. 157-173, pls. 23-
26, June 17, 1939.

(822) Not represented in the present collections.

(823) A discussion of the effect of brackish water in the Baltic
Sea upon the shell of Cardiwm edule is given in a paper by Gold-
ring (New York State Museum Handbook No. 10, p. 105, 1931)
and others (see Purchon, R. D., Proc. Malacol. Soc. London, Vol.
28, Pt. 5, pp. 256-267, figs. 1-3, July 15, 1939).

(824) Trachycardium Morch, Cat. Conchyl. Yoldi, Pt. 2, p. 34,
1853. Type designated by von Martens (1870): Cardium isocardia
Linnaeus. See discussion of this species by Dodge (Bull. Amer.
Mus. Nat. Hist., Vol. 100, Art. 1, p. 59, 1952). Also, Stewart, 1930,
p. 263.

(825) Eames, F. E., Philos. Trans. Roy Soc. London, Ser. B, No.
627, Vol. 235, p. 409, 1951.

(826) Gardner, J., Bull. Amer. Assoc. Petrol. Geol., Vol. 25, No. 4,
p. 647, 1941.

(828) Stephenson, L. W., U.S.G.S., Prof. Paper 242, p. 102, pl. 24,
figs. 1-7, 1952.

(828) Finlay, H. J., and Marwick, J., Trans. Roy. Soc. New Zea-
land, Vol. 70, Pt. 1, p. 126, 1940.

(829) Cardium quadrigenarium Conrad var. fernandoensis Ar-
nold, Proc. U.S. Nat. Mus., Vol. 32, No. 1545, p. 535, pl. 48, figs. 2,
2a, June 15, 1907. ““Locality.—Elsmere Canyon, near Pacific Coast
Oil Company’s well, 2’ miles southeast of Newhall, Los Angeles
County, California. (Ralph Arnold).” Pliocene.

A fossil form cited by Khomenko under this name from Plio-
cene strata in Kamtschatka was later referred to Papyridea
kipenensis Slodkewitsch (See Paleo. USSR, Vol. 10, Pt. 3, Fasc.
18, Tert. Pelecypoda from the Far East, p. 409, 1938; Fase. 19, p.
159, pl. 82, figs. 1, 2; pl. 83, figs. 1, 2, 3, 1938.)

(830) Trachycardium sagaseri Adegoke, Univ. Calif. Publ.
Geol. Sci., Vol. 80, p. 116, pl. 3, figs. 4, 6, 8, September 25, 1969.
(831) Cardium (Trachycardium) vaqueroensis Arnold, Proc.
U.S. Nat. Mus., Vol. 34, No. 1617, p. 378, pl. 34, fig. 8, August 8,
1908. “Santa Cruz quadrangle, San Mateo County, Locality No.
12, Mindego Creek, 1 mile above its confluence with Alpine
Creek.” “Vaqueros formation, lower Miocene.”

Tikonovich (Mém. du Comité Géol. Nouv. Sér., Livr. 82, p. 39,
1914) cited this species as occurring in Tertiary strata in the

- Schmidt Peninsula, North Sakhalin, but that record is almost
_ certainly referable to some other species.

(832) Cardiwm (Trachycardium) gorokuense Nomura, Sci.
Repts. Tohoku Imper. Univ., Sendai, Japan, Ser. 2 (Geol.), Vol.
19, No. 2, p. 256 (22), pl. 34 (2), figs. 15, 15a, 1988. Tatunokuti shell
bed at Goroku cliff, Sendai, Japan. Pliocene.

(833) See Beal, C. H., Geol. Soe. Amer., Mem. 31, p. 66, 1948.

367

(Identification by J. Gardner.)

(834) Cerastoderma Poli in Mérch. Cat. Conchyl. Yoldi, Pt. 2, p.
34, 1853. Type (designated by von Martens, Zool. Rec., Vol. 6, p.
586, 1869 on title page, issued 1870): Cardiwm edule Linnaeus. Il-
lustrated by Buequoy, Dautzenberg, and Dollfus, Moll. Mar.
Roussillon, Tome 2, Fase. 7 (Pelecypoda, Fasc. 20), p. 284, pl. 46,
figs. 1-4; figs. 5-10 (vars.) and pl. 47, figs. 1-17 (vars.), 1892. Medi-
terranean to Black Sea; Caspian Sea; Atlantic Ocean from Ice-
land and Finmark to Morocco and the Canary Islands.

(835) Laevicardium Swainson, Treatise on Malacol., p. 373,
1840. Type (designated by Stoliezka, Mem. Geol. Surv. India,
Palaeont. Indica, Ser. 6, Vol. 3, p. X VIII, 1871): “Typical species. C.
oblongum, Chem.,” Recent.—Buequoy, Dautzenberg, and Doll-
fus, Moll. Mar. Roussillon, Tome 2, Fasc. 7, (Pelecypoda, Fase. 20),
p. 303, pl. 49, figs. 1-4, 1892. Mediterranean and Adriatic.

(836) See Keen, A. M., “Five new species and a new subgenus in
the Pelecypod Family Cardiidae,” Bull. Amer. Paleo., Vol. 35, No.
153, pp. 311 (5)-330 (24), pl. 29 (1), figs. 1-9 in text, December 20,
1954. [Clinocardium, pp. 320 (14)-330 (24).]

(837) See Hirayama, K., "The Asagai Formation and its Mollus-
can Fossils in the Northern Region, J6ban Coal-Field, Fukushima
Prefecture, Japan,’ Sci. Repts. Tokyo Kyoiku Daigaku, Sec. C.
(Geol. Miner. Geogr.), No. 29, pp. 49-130, pls. 1-5, figs. 1-3 in text,
March 10, 1955. (Clinocardium, pp. 92-99.)

(838) Etherington cited “Cardium (Cerastoderma) ef. corbis
Martyn” from beds of middle Miocene age in southwest Washing-
ton (Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 20, No. 5, p. 77, pl.
5, fig. 11, 1931), and Moore recorded Clinocardium aff. C. nuttalliv
Conrad from strata of middle Miocene age in Oregon (U.S.G.S.,
Prof. Paper 419, p. 73, pl. 30, figs. 1, 2, 1963). Keen (Bull. Amer.
Paleo., Vol. 35, No. 153, p. 323 (17), 1954) believed that Ether-
ington’s record might be referable to either Clinocardium pristi-
num Keen or perhaps to an unnamed species.

(839) See Fraser, C. McL., Trans. Roy. Soc. Canada, See. 5, Biol.
Sci., Ser. 3, Vol. 25, pp. 59-72, pls. 1-8, May, 1931. See also
Weymouth, F. W., and Thompson, S. H., Bull. U.S. Bur. Fish., Vol.
46 (Document No. 1101), pp. 633-641, figs. 1-7, issued March 6, 1931.
(840) Keen, A. M., in Burch, J. Q. (ed.), Min. Conch. Club South.
California, No. 41, p. 23, November, 1944.

(841) Mitchell, H. D., “The microscopic structure of the shell and
ligament of Cardium (Cerastoderma) corbis Martyn,” Jour.
Morph., Vol. 58, No. 1, pp. 211-220, figs. 1-6 in text, September 5,
1935.

(842) See Taylor, C. C., “Temperature, growth, and mortality—
The Pacifie Cockle,” Jour. du Conseil, Vol. 26, No. 1, pp. 117-124,
figs. 1-5, December, 1960.

(843) Cardium meekianum Gabb, Geol. Surv. Calif., Palaeo.,
Vol. 2, p. 27, pl. 7, fig. 46, 1866. “Locality: Humboldt County, As-
sociated with Callista voyi, &.”—Stewart, Acad. Nat. Sci. Phila-
delphia, Spec. Publ. No. 3, p. 262, pl. 13, fig. 5, 1930 (as Cerasto-
derma meekianum). [Holotype.] “Horizon, Pliocene; locality,
Eagle Prairie, Humboldt County.”

(844) Clinocardium meekianum (Gabb) myrae Adegoke, Univ.
Calif. Publ. Geol. Sci., Vol. 80, p. 117, pl. 3, figs. 7, 9; pl. 7, fig. 6,
September 25, 1969.

(845) See Slodkewitsch, W.S., Paleontology of USSR, Vol. 10, Pt.
3, Fasc. 19, “Tertiary Peleeypoda from the Far East,” Pt. 2, p. 154,
pl. 76, figs. 1, 2, 3; pl. 77, figs. 1, 2; pl. 78, fig. 1, 1938 [English text].
See also Fasc. 18, p. 383 [Russian text].

(846) See Hatai, K., and Nisiyama, S., ‘Checklist of Japanese
Tertiary Marine Mollusca,” Sci. Repts. Tohoku Univ., Sendai, Ja-
pan, Second Ser. (Geol.), Spec. Publ. No. 3, p. 39, 1952.

(847) “Clinocardium” nomurai Hayasaka, Saito Ho-on Kai
Mus., Res. Bull. No. 25, p. 18, pl. 2, figs. 4a, 4b, November, 1956.
Futaba District, Fukushima Prefecture, Japan, Pliocene.

(848) Cardium shinjiensis Yokoyama, Jap. Jour. Geol. Geogr.,
Vol. 2, No. 1, p. 7, pl. 2, fig. 6, March, 1923. ‘“Fujina, Neo. Ka-
gami.” Neogene. See also Makiyama, J., Palaeo. Soc. Japan, Spec.

368

Paper No. 3, pl. 6, fig. 6, 1937, and Hirayama, K., Sci. Repts.
Tokyo Kyoiku Daigaku, Vol. 4, Sec. C (Geol. Min. Geogr.), No. 29,
p. 96, pl. 2, figs. 4, 10, 1955.

(849) Keen, A. M., “Notes on the history of Nemocardium
(Family Cardiidae).” Jour. de Conchyl., Vol. 90, No. 1, pp. 23-29,
January, 1950.

(850) Finlay, H. J., and Marwick, J., Trans. Roy. Soc. New Zea-
land, Vol. 70, Pt. 1, pp. 111, 121, 1940.

(851) Cardium weaveri Anderson and Martin, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 4, p. 57, pl. 1, figs. 3a, 3b, December 30,
1914. ‘From bluffs at the west end of the railroad tunnel about
three miles southeast of Timber, Oregon.” “Lower Miocene, or
possibly Oligocene.”

(852) Hickman, Carole J. S., Mus. Nat. Hist. Univ. Oregon, Bull.
No. 16, p. 35, pl. 2, figs. 11, 12, August, 1969, Eugene Formation.
(853) Cardium bechei A. Adams and Reeve, Zool. Voy. Sama-
rang, Moll., Pt. 3, p. 78, pl. 22, fig. 12, issued 1850. ‘Hab. Sooloo
and Yellow Seas.” “Only two odd valves of this pre-eminently
beautiful shell were obtained, and, singularly, in localities very
remote from each other: one was dredged at the depth of forty
fathoms in the Sooloo Seas, between the islands of Borneo and
Mindanao; the other in the Yellow Sea, thirty degrees north, at
one of the islands of the Corean Archipelago.”

(854) Stewart, R. B., Acad. Nat. Sci. Philadelphia, Spec. Paper
No. 3, pp. 272, 273, 1930.

(855) Davies, A. M., Tertiary Faunas, Vol. 1, p. 121, 1925.

(856) See Wright, L. A., Bull. Geol. Soc. Amer., Vol. 59, No. 12,
Pt. 2, p. 1390, 1948. Basal Modelo (?) in Reynier Canyon, Los An-
geles Co., California, late Miocene; see also Dehlinger, P., Calif.
State Div. Mines, Spec. Rept. 26, p. 6, 1952. Modelo, southern
ridge route, late Miocene. (Identification by J. W. Durham).
(857) Cardium richardsoni Whiteaves, Canadian Nat., New
Ser., Vol. 8, No. 8, p. 468, 1878. “Strait of Georgia, between Race
Island Lighthouse and Victoria Harbour, in 30 to 50 fathoms.”
Illustrated by Dall, W. H., U.S. Nat. Mus., Bull. 112, p. 40, pl. 2,
fig. 3, 1921.—I. S. Oldroyd, Publ. Puget Sound Biol. Sta., Vol. 4, p.
44, pl. 16, fig. 7, 1924; Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 146, pl. 2, fig. 7, 1924. ?
(858) Dall, W. H., Proc. U.S. Nat. Mus., Vol. 23, No. 1214, p. 391,
1901.

(859) Willett, G., in Burch, J. Q., Min. Conch. Club South. Calif.,
No. 41, p. 27, November, 1944.

(860) See Woodring, W. P., Bramlette, M. N., and Kew, W. S.
W., U.S.G.S., Prof. Paper No. 207, p. 85, pl. 33, figs. 10, 11, 1946.
(861) Cited as “Famille. Veneridia” by Rafinesque, 1814; as
“Fam. 5 Veneracea”’ by Menke, 1830; as ‘“Venereaca”’ by Anton,
1839.

(862) Cited as “Family I1I.—Veneridae” by Leach in Ross, 1819
(Ann. Philos., Vol. 14, p. 204, 1819).

(863) Dall, W. H., “Synopsis of the Family Veneridae and of the
North American Recent Species,” Proc. U.S. Nat. Mus., Vol 26,
No. 1312, pp. 335-412, pls. 12-16, December 29, 1902. See also von
Ihering, H., “Zur Geschichte der Venus-Muscheln,” Archiv f.
Molluskenkunde, Jahrg. 53, Heft 3, pp. 125-139, 1921.

(864) Jukes-Browne, A. J., “A synopsis of the Family Vener-
idae,” Proce. Malacol. Soc. London, Vol. 11, Pt. 1, pp. 58-74,March,
1914; Vol. 11, Pt. 2, pp. 75-94, June, 1914.

(865) Marwick, J., “The Veneridae of New Zealand,” Trans. New
Zealand Inst., Vol. 57, pp. 567-635, pls. 34-54, 1926 (1927).

(866) Palmer, K. V. W., “The Veneridae of Eastern America, Ce-
nozoic and Recent,”’ Paleontogr. Americana, Vol. 1, No. 5, pp. 209-
517 (1-208), figs. 1-35 in text, March 1927, pls. 32-76 (1-45), Febru-
ary, 1929.

(867) Frizzell, D. L., Preliminary Reclassification of Vener-
acean Pelecypods,” Bull. Mus. Roy. d’Hist. Nat. Belgique, Tome
12, No. 34, pp. 1-84, December, 1936.

(868) Casey, R., “Some Genera and Subgenera, mainly new, of
Mesozoic Heterodont Lamellibranchs,” Proe. Malacol. Soc. Lon-

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

don, Vol. 29, Pt. 4, pp. 121-176, pls. 7-9, figs. 1-100 in text, May 9,
1952. (Veneridae, pp. 156-173.)

(869) Keen, A. M., "Nomenclatural notes on the Pelecypod Fam-
ily Veneridae,” Min. Conch. Club South. California, No. 139, pp.
50-55, June, 1954.—See also Keen, Treatise on Invertebrate Pa-
leontology (Geol. Soc. Amer. and Univ. Kansas), Part N, Vol. 2, pp.
N670-N690, figs. E142-E.152, 1969.

(870) See Hertlein, L. G., and Strong, A. M., “Eastern Pacific Ex-
peditions of the New York Zoological Society. XX XIX. Mollusks
from the west Coast of Mexico and Central America. Part VI,”
Zoologica, Vol. 33, Pt. 4, pp. 163-198, pls. 1,2, December 31, 1948.
(871) See Keen, A. M., Sea Shells of Tropical West America
(Stanford Univ. Press: Stanford, California), 1958. (See Vener-
idae, pp. 122-150, figs. 267-344).

(872) See Olsson, A. A., Mollusks of the Tropical Eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), Veneridae, pp. 257-313,
March 10, 1961.

(873) Ansell, A. D., “The functional morphology of the British
species of Veneracea (Eulamellibranchia),” Jour. Mar. Biol. As-
soc. U.K., Vol. 41, No. 2, pp. 489-517, figs. 1-15 in text, June, 1961.
(874) Adapted from Hertlein, L. G., and Strong, A. M., 1948, pp.
164-165.

(875) Not known with certainty from the San Diego Formation.
(876) See Durham, J. W., “The Pelecypod Dosinia in the lower
Oligocene of California,” Veliger, Vol. 2, No. 2, pp. 21-24, pl. 4, Oc-
tober, 1959.

(877) Ashley in 1895 reported the occurrence of Dosinia ponde-
rosa in strata of Pliocene age in San Mateo County. Apparently no
specimens have been reported subsequently from beds of that age
in that area (see Addicott, Proc. Calif. Acad. Sci., Ser. 4, Vol. 37,
No. 3, p. 82, 1969).

(878) Arthemis ponderosa Gray, Analyst, Vol. 8, p. 309, 1888. [No
locality cited.]—Reeve, Conch. Icon., Vol. 6, Artemis, sp. 4, pl. 1,
fig. 4, 1850 (as Artemis ponderosa). “Hab. Gulf of California (in
sandy mud at low water).’’—Grant and Gale, Mem. San Diego Soe.
Nat. Hist., Vol. 1, p. 351, pl. 15, figs. la, 1b, le, 1931 (as Dosinia
ponderosa). Earlier records cited. Pleistocene and Recent.

(879) Dosinia jacalitosana Arnold, U.S.G.S., Bull. 396, p. 67, pl.
16, fig. 5, 1909. “United States Geological Survey locality 4763, 200
yards north of Jacalitos Creek on the Stone Canyon and Coalinga
road, on the flanks of Waltham Valley, 14 miles southwest of Coa-
linga.” “Jacalitos formation, lower part of upper Miocene.”
[Early Pliocene. ]

(880) See Nomland, J. O., Univ. Calif. Publ. Bull. Dept. Geol., Vol.
10, No. 14, pl. 10, fig. la, 1917.

(881) See Keen, A. M., in Burch, J. Q., Min. Conch. Club South.
California, No. 51, p.31, August, 1945.

(882) See Fitch, J., “Growth and Longevity of Pismo clams,”
Shells and their neighbors, No. 10, pp. 5-6, figs. 1-3, April, 1962.
(883) See Orcutt, C. R., West Amer. Sci., Vol. 6, Whole No. 45, p.
70, 1889.

(884) Campbell, A. S., “Some Common Chinese Mollusca,” Jour.
Entomol. Zool., Vol. 15, No. 3, p. 41, September, 1923.

(885) Woodring, W. P., “Age of the Orbitoid-bearing Eocene
Limestone and Turritela variata zone of the western Santa Ynez
Range, California,” Trans. San Diego Soc. Nat. Hist., Vol. 6, No.
25, p. 376, 1931.

(886) Tivela scarificata Berry, Bull. Amer. Paleo., Vol. 25, No.
94A, p. 151(5), pl. 17(1), fig. 5, September 28, 1940. “Type local-
ity.—N. W. corner Beacon and Second Streets, San Pedro, Cali-
fornia.”’ Pleistocene.

(887) Fitch, J. E., “The Bean Clam—Donaz gouldi.” Paper pre-
sented at Eleventh Ann. mtg. Amer. Malacol. Union Pacific Div.,
Berkeley, California, June 27, 1958, 1 page [mimeographed].
(888) Weymouth, F. W., “The Life-History and Growth of the
Pismo Clam (Tivela stultorum Mawe),” Fish Game Comm., Fish
Bull. No. 7, pp. 1-120, figs. 1-15, 1928. [See also review of this pa-
per by S. S. Berry, Nautilus, Vol. 38, No. 2, pp. 68-71, October,

|
)

|

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

1924. ]

(889) Fitch, J. E., “The Pismo Clam,” California Fish Game,
Vol. 36, No. 3, pp. 285-312, figs. 116-128, July, 1950.

(890) See Baugh, A. C., “A History of the English Language”
(D. Appleton-Century Company, Inc.: New York), p. 21, 1935.
(891) See Jacobs, T. J., Scenes, Incidents and Adventures in the
Pacific Ocean, or, the Islands of the Australian Seas, during the
cruise of the Clipper Margaret Oakley, under Capt. Benjamin
Morrell (Harper & Bros.: New York), pp. 88, 84, 1844. For ex-
ample, ‘Pitar Cave.”

(892) Katherinella Tegland, Univ. Calif. Publ. Bull. Dept. Geol.
Sci., Vol. 18, No. 10, p. 280, May 8, 1929. “Genotype.—Callocallista
arnoldi Weaver,” Univ. Washington Publ. Geol., Vol. 1, No. 1,
p- 40, pl. 2, fig. 18, February, 1916 (as Callocallista arnoldi). “in
railways cuts on the O. -W. R. R. & N. Co. one fourth mile north-
west of Lincoln Creek Station in Section 27, Township 15 North,
Range 3 West.” ‘“Lowermost Oligocene; Molopophorous lincol-
nensis zone.” See also discussion of the genus Katherinella by
Stenzel, Krause, and Twining (Univ. Texas, Bull. Bur. Econ.
Geol., No. 5704, pp. 133-135, 1957) and by Moore, Ellen J.
(U.S.G.S., Prof. Paper. 419, pp. 76-77, 1963).

(893) Earlier in this memoir (1944, p. 48) we referred this record
to ?Compsomyax subdiaphana Carpenter.” Whether or not is is
referable to that species or the present one is open to question.
(894) Macrocallista Meek, Rept. U.S. Geol. Surv. Territories,
Vol. 9, p. 179, 1876. Type (by monotypy): Venus gigantea Gmelin.
(895) The species described as Cytherea newcombei by Merriam
from the Sooke formation, probably of early Miocene age, on
Vancouver Island, British Columbia, was later referred to Com-
psomyax (as subgenus of Venerella) by Weaver (Univ. Wash-
ington Publ. Geol., Vol. 5, Pt. 1, p. 193, pl. 42, fig. 17; pl. 43, fig, 9;
pl. 45, figs. 6, 8, 15, 17, 18, 1942 (issued Dee. 31, 1943).)

(896) See footnote 892.

(897) See Kobelt, W., Illustr. Conchylienbuch, Bd. 2, p. 339, 1881.
“Murcia Ad., glatte Arten mit dem Typus V. pinguis Chemn.”
(Syst. Conchyl. -Cab., Bd. 6, p. 355, Tab. 34, figs. 355-357, 1782.
“ostindischen Meeren.”’) [= Venus opima Gmelin.] [Some au-
thors have considerd Venus exalbida Chemnitz (Syst. Conchyl.
Cab., Bd. 11, p. 225, Tab. 202, fig. 1974, 1795. “Sie sey bey den
Falklandsinsuln gefunden worden’’) to be the type as designated
by Dall, 1902.]

(898) Venerella Cossmann, Ann. Soc. Roy. Malacol. Belg., Vol.
21, p. 105, 1886. Type (designated by Crosse, Journ. de Conchyl.
Vol. 34, No. 4, p. 381, 1886): “(type Venus Hermonvillensis,
Deshayes)” [see Descript. Anim. s. Vert. Bassin Paris, Vol. 1, p.
405, pl. 28, figs. 1-5, 1860. “Hermonville, Damery, Fleury,
Boursault.” “Caleaire grossier supérieur.”” Lutétien, Eocene. }
(899) See Etherington, J. T., Univ. Calif. Publ. Bull. Dept. Geol.
Sci., Vol. 20, No. 5, p. 78, pl. 6, figs. 1, 2, 3, 1931.

(900) See Moore, Ellen J., U.S.G.S., Prof. Paper 419, p. 78, pl. 25,
fig. 16, 1963.

(901) See Marcia (Mercimonia) angustifrons Conrad, Ether-
ington, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 20, No. 5, p.
81, pl. 6, fig. 4; pl. 7, fig. 83, 1931. Miocene of southwestern Wash-
ington. See also Moore, E. J., U.S.G.S., Prof. Paper 419, p. 77, pl.
2A, figs. 11-14; pl. 25, figs. 1-3, 5-15; pl. 26, figs. 4, 6, 8, 1963 (as
Katherinella (Katherinella) angustifrons).

(902) See Marcia (Mercimonia) angustifrons var. brevilineata
Conrad, Etherington, Univ. Calif. Publ. Bull. Dept. Geol. Sci.,
Vol. 20, No. 5, p. 82, pl. 6, figs. 6, 7, 1931. Miocene of southwestern
Washington.

(903) See Travis, R. B., Calif. State Div. Min., Bull. 162, p. 21,
1952.

(904) See Woodring, W. P., U.S.G.S., Prof. Paper 222, p. 89,
1950.

(905) Saxidomus gibbosus Gabb, Geol. Sury. Calif., Palaeo., Vol.
2, p. 58, pl. 16, figs. 18, 18a, 18b, 1869. ‘Common in the Pliocene of
Eagle Prairie, Humboldt County.”—Stewart, Acad. Nat. Sci.

369

Philadelphia, Spec. Publ. 3, p. 224, pl. 14, fig. 6, 1930 [as Venerella
(Compsomyax) subdiaphana}.

(906) Clementia obliqua Jukes-Browne, Ann. Mag. Nat. Hist.,
Ser. 8, Vol. 12, No. 67, p. 60, pl. 1, figs. 1, 2, July, 1913. “Purchased
by Mr. J. C. Melvill at the recent sale of Mr. Biilow’s collection.”
“Accompanied by a ticket bearing the inscription ‘Caryatis
aresta, Dall and Simpson, Mayaguez, Porto Rico’.” See Dall,
Nautilus, Vol. 27, No. 9, p. 103, 1914.

(907) Merretriz tizukai Yokoyama, Jour. Coll. Sci. Imper. Univ.
Tokyo, Vol. 45, No. 5, p. 20, pl. 3, figs. 2, 3, March 21, 1925. Up-
permost strata of the Jé-Ban Coalfield in Japan. Cited as Plio-
cene age but Hatai and Nisiyama, 1952, referred it to the Mio-
cene.

(908) Clementia (Compsomyax) subdiaphana yazawaensis
Otuka, Bull. Earthquake Res. Inst., Vol. 12, Pt. 3, p. 617, 1934.
Lower Kadonosawa series, Miocene.

(909) Clementia (Compsomyax) aff. subdiaphana Carpenter,
Otuka, Bull. Earthquake Res. Inst., Vol. 12, Pt. 3, p. 617, pl. 48,
fig. 42, 1934. Shikonai, Miocene.

(910) Romer, E., “Ueber Saxidomus,” Malakozool. Blatter, Bd.
8, pp. 63-70, 1861.

(911) Saxidomus (?) noblei Dickerson, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 8, No. 15, p. 300, pl. 29, fig. 1, December 10, 1914.
“University of California Locality 2249, two and three-fourths
miles N.80°W of U.S. Geological Survey bench mark (3927 ft.) at
Shoemaker, Rock Creek Quadrangle, Los Angeles County, Cali-
fornia. Martinez Group.”

(912) Saxidomus popofianus Dall, Res. Harriman Alaska Ex-
ped., Wash. Acad. Sci. (later reissued by the Smithsonian In-
stitution), Vol. 4, p. 115, pl. 10, fig. 4, 1904. “Locality.—Popof
Island, 3372.” Shumagin Islands, Alaska, ‘'Miocene.”

(913) Venus opaca Sowerby, Proc. Zool. Soc. London for 1835,
p. 42, issued June 1, 1835. “Hab. ad oras Chilenses. (Conception
and Maule.)” “Found in sandy mud at low water.”—Sowerby,
Thes. Conch., Vol. 2, p. 691, pl. 150, fig. 128, 1885 (as Tapes
opaca).

(914) See Saxidomus opacus Sowerby, Carcelles, A. R., and Wil-
liamson, S. I., “Catalogo de los Moluscos Marinos de la Provincia
Magallanica,” Rev. Inst. Nac. Invest. Cienc. Nat. anexo al Mus.
Argentino de Ciene. Nat. ‘Bernardo Rivadavia,” Cienc. Zool.,
Tomo 2, No. 5, p. 341, 1951. ‘Pert y Chile.”

(915) Eurhomalea Cossmann, Rev. Crit. de Paléozool., Vol. 24,
No. 3, p. 187, July, 1920. New name for Rhomalea Jukes-Browne,
1914. (Type, Venus rufa, Lamarck’’). Not Rhomalea Bur-
meister, 1839.

(916) See Soot-Ryen, T., Lund Univ. Arsskr., N. F., Avd. 2, Bd.
55, No. 6, p. 59, 1958;—also Herm, D., Zitteliana, Abhand. Bayer.
Staatssammlung f. Palao. u. Hist. Geologie, 2, p. 129, pl. 6, figs. 5,
6, 1969.

(917) See Ihering, H. von, Ann. Mus. Nac. Buenos Aires, Vol. 14
(Ser. 3, Vol. 7), p. 297, 1907.

(918) Cited from the “Temblor” by J. P. Smith, 1912; from
“lower Miocene beds” by Anderson and Martin, 1914; from ‘“Va-
queros-Temblor” by Nomland, 1917; from the “Topanga forma-
tion” by Grant and Quayle in Soper, 1938. Cited with question
from the “Temblor Horizon” by Loel and Corey, 1932.

(919) Venerupis gigantea Deshayes, Rev. Zool., Soc. Cuvie-
rienne, Ann. 1839, p. 359, December, 1839. “Californie.”—Grant
and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p. 342, pl. 18,
figs. 4, 10, 1931 (as Saridomus nuttalli Conrad variety gi-
ganteus).

(920) Saxidomus vaquerosensis Arnold, U.S.G.S., Bull. 396, p.
56, pl. 7, fig. 7, 1909 (January 15, 1910). “Locality 4631, Twurritella
ocoyana bed, SE. 4 NE. \% sec. 16, T. 19 S., R. 15 E.” “Vaqueros
formation, lower Miocene” [Temblor, middle Miocene].

(921) See Hertlein, L. G., and Jordan, E. K., Proc. Calif. Acad.
Sci., Ser. 4, Vol. 16, No. 19, pp. 608, 610, 625, 1927.

(922) See Khomenko, I. P., Trans. Geol. Oil Inst., Ser. A, Fase.

370

103, p. 48, pl. 10, figs. 4, 5, 1938.

(923) See Hatai, K., and Nisiyama, S., Sci. Repts. Tohoku Univ.,
Sendai, Japan, Second Ser. (Geology), Spec. Vol. No. 3, p. 138,
1952.

(924) See Smith, G. M., Trans. Roy. Soc. Canada, Ser. 3, Vol. 27,
See. 5, pp. 229-245, 1933.

(925) Gavala y Laborde, J., “Revisién de las especies de mo-
luscos figuradas por Thomas Martyn en su obra ‘The Universal
Conchologist’,”” Rev. Real Acad. Cienc. Exactas, Fis. y Nat. de
Madrid, Tome 58, Cuad. 3, p. 357, 1964.

(926) Martyn, T., The Universal Conchologist, Vol 4, pl. 148,
1789. See also Chenu, Bibl. Conchyl., Vol. 2, p. 30, pl. 50, fig. 1,
1845.

(927) Parker, P. ‘Fossil and Recent species of the Pelecypod
genera Chione and Secwrella from the Pacific Coast,’ Jour.
Paleo., Vol. 23, No. 6, pp. 577-593, pls. 89-95, November, 1949.
(928) Iliochione Olsson, Mollusks of the tropical eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), p. 297, March 10, 1961.
“Type species, Venus subrugosa Sowerby, 1853 ( = Venus swb-
rugosa Wood).”

(929) See Chione (C.) californiensis var. gealeyi Parker, Jour.
Paleo., Vol. 23, No. 6, p. 580, pl. 90, figs. 7, 10, 1949. “Mission Bay,
San Diego, California.”

(930) Venus asperrima Sowerby, Proc. Zool. Soc. London for
1835, p. 42, June 1, 1835. “Hab. ad Insulam Lobos dictam.”
“Found in fine sand at low water.’”—Olsson, Mollusks of the
Tropical Eastern Pacific (Paleo. Res. Inst.: Ithaca, New York), p.
307, pl. 58, figs. 8, 3a; pl. 54, fig. 6, 1961 (as Nioche (Nioche) asper-
rima asperrima). Guaymas, Sonora, Mexico.

(931) Venus californiensis Broderip, Proc. Zool. Soc. London,
for 1835, p. 48, issued June 1, 1835. “Hab. in sinu Californiae.
(Guaymas.)” “Found in sandy mud at low water.”—Reeve,
Conch. Icon., Vol. 14, Venus, species 35, pl. 11, fig. 35, 1863. Origi-
nal locality cited._Keen, Sea Shells of Tropical West America
(Stanford Univ. Press; Stanford, California), p. 140, fig. 318, 1958
[as Chione (Chione) californiensis]. Point Mugu, California, to
Panama, Recent.

(932) Chione semiplicata Nomland, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 10, No. 18, p. 305, pl. 15, figs. 2a, 2b, 2c, Novem-
ber 8, 1917. “From locality 2283, in small gulley near SE corner
of NW 4 of NW 44sec. 15, T. 19S, R. 15 E, M.D.B.&M., about nine
miles northeast of Coalinga.” Santa Margarita Formation, late
Miocene.

(933) Chione margaritana Anderson and Martin, Proce. Calif.
Acad. Sci., Ser. 4, Vol. 4, p. 59, pl. 2, fig. 1, December 30, 1914.
“from the top of the Santa Margarita beds in the N.E. 4 of Sec.
25, T. 2158., R. 14 E.” Late Miocene.

(934) Chione panzana Anderson and Martin, Proc. Calif. Acad.
Sci., Ser. 4, Vol. 4, p. 58, pl. 1, figs. la, 1b, December 30, 1914.
“San Luis Obispo County, California, in a small creek about % of
a mile southwest of Lewis House, near the center of the S.E. 4
of Sec. 22, T. 29, S., R. 16 E., Mt. D.B.L. and M.” “Lower Mio-
cene.”

(935) See Parker, P., Jour. Paleo., Vol. 23, No. 6, p. 592, Novem-
ber, 1949.

(936) Chione vickeryi Wiedey, Jour. Paleo., Vol. 3, no. 3, p. 286,
pl. 32, fig. 4, September, 1929. “Collected 500 yards upstream
from the falls in Alum Rock Canyon, just east of San Jose, Santa
Clara County, California.” ‘Upper Monterey formation, middle
Miocene.”

(937) Chione schencki Loel and Corey, Univ. Calif. Publ. Bull.
Dept. Geol. Sci. Vol. 22, No. 3, p. 224, pl. 42, fig. 5, December 21,
1932. “from buff calcareous sandstone at head of Corral de
Piedra Creek, about five miles east of San Luis Obispo.” [Cited
from beds of early Miocene age but according to Parker (p. 584)
the type bears the same locality number as C. vickeryi and “It is
obviously not a Vaqueros species.’’]

(938) Chione elsmerensis English, Univ. Calif. Publ. Bull. Dept.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Geol., Vol. 8, No. 8, p. 214, pl. 23, figs. la, lb, November 7, 1914.
“From lower Fernando, Elsmere Canyon. Univ. Calif. Loe.
1735.”

(939) Hertlein, L. G., Stanford Univ. Bull., Ser. 5, No. 78, pp. 84,
85, 1929. San Diego Pliocene.

(940) Chione fernandoensis English, Univ. Calif. Publ. Bull.
Dept. Geol., Vol. 8, No. 8, p. 215, pl. 23, figs. 9a, 9b, November 7,
1914. “Elsmere Caftyon, Univ. Calif. Loc. 1602” (p. 218). “Lower
Fernando,” Pliocene.

(941) See Keen, A. M., and Bentson, H., Geol. Soc. Amer., Spec.
Papers No. 56, p. 36, 1944.

(942) See Parker, P., Jour. Paleo., Vol. 28, No. 6, p. 585, pl. 95,
figs. 7, 8, 18, 14, 15, 16, 18, November, 1949.

(943) Venus mariae d’Orbigny, Voy. Amér. Mérid., Vol. 5, p.
563, 1846. ‘“M. Cuming l’a pechée 4 Vile de la Plata, sur les cotes
de la république de l’Equateur.”” New name for Venus cypria So-
werby, 1835, not Venus cypria Brocchi, 1814, nor Venus cypria
Risso, 1826. Illustrated by Reeve, Conch. Icon., Vol. 14, Venus, sp.
116, pl. 28, figs. 116a, 116b, 1863.

(944) “Paphia cf. staleyi (Gabb)” was reported from the “Tem-
blor Horizon” by Loel and Corey (Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 22, No. 3, p. 145, 1932).

(945) von Ihering, H., Ann. Mus. Nac. Buenos Aires, Vol. 14
(Ser. 3a, Vol. 7), p. 296, 1907.

(946) Marwick, J., New Zealand Jour. Sci. Tech., Vol. 8, no. 5, p.
272, 1926.

(947) Hatai, K., and Nisiyama, S., Sci. Repts. Tohoku Univ.
Sendai, Japan, Second Ser. (Geol.), Special Vol. 3, p. 132, 1952.
(948) Novathaca Habe, Gen. Jap. Shells, Pelecypoda No. 2, p.
180, September, 1951. “Type species: Chione euglypta Sowerby.”
(949) Tropithaca Olsson, “Mollusks of the Tropical Eastern
Pacific” (Paleo. Res. Inst.: Ithaca, New York), p. 305, March 10,
1961. “Type species Protothaca grata (Say).” Illustrated on pl.
53, figs. 2-2b, 7.

(950) Tuangia Marwick, Trans. New Zealand Inst., Vol. 57, p.
623, February 12, 1927. “Type: Venus crassicosta Deshayes,”’ pl.
49, figs. 178, 181, 182.

(951) See Gale, H. R., in Preston, H. M., Summ. Oper. Calif. Oil
Fields, Vol. 16, no. 4, p. 15, April, May-June, 1931. Woodring,
Bramlette, and Kew (1946, p. 27) reported ‘“‘Callithaca? ef. C.
staminea (Conrad)” from the “middle part of Altamira shale
member of Monterey shale,” of probable middle Miocene age.
(952) Protothaca kovatschensis Ilyina, Trudy Vsesoiuznogo
Neftianogo Nauchno-issledovatel’skogo Geologorazvedochnogo
Inst. (VNIGRI) (Moskva), Vypusk 202, p. 52, pl. 18, fig. 8, 1963.
(953) See Smith, G. M., “Further observations on the ecology,
rate of growth and food supply of some Pacific clams.” Trans.
Roy. Soc. Canada, Ser. 3, Vol. 27, sec. 5, pp. 229-245, figs. 1-5 in
text, 1 map, 1938.

(954) W. O. Addicott and J. G. Vedder (U.S.G.S., Prof. Paper
475C, p. C67, 1963) reported “Protothaca cf. P. tenerrima” from
the Santa Margarita Formation of late Miocene age at Co-
manche Point, Kern Co., California.

(955) Paphia restorationensis Frizzell, Nautilus, Vol. 43, No. 4,
p. 120, April, 1930. “Fairly common in late Pleistocene beds at
Restoration Point, near Port Blakely, Washington, and ex-
tremely rare living in Puget Sound.”—Frizzell, Trans. San Diego
Soe. Nat. Hist., Vol. 6, No. 21, p. 321, pl. 22, figs. 1, 2, 3, 4, April
30, 1931.

(956) Irus Oken, Lehrbuch Zool., p. 230, 1815. Type (by tauto-
nomy): Donax irus Linnaeus [Syst. Nat., ed. 10, p. 688, 1758.
“Habitat in M. Mediterraneo.” Ref. to ‘Gault. test. t. 95. f.A.” Il-
lustrated by Bucquoy, Dautzenberg, and Dollfus, Moll. Mar.
Roussillon, Vol. 2, Fase. 9 (Pelecypoda Fasc. 22), p. 488, pl. 67,
figs. 9-18, 1893. See also Venerupis irus Linnaeus, Cossmann
and Peyrot, Act. Soc. Linn. Bordeaux, Vol. 65 (Conch. Néog.
l’Aquitaine Vol. 1, Livr. 3), fig. 81, p. 432 (hinge), p. 433, pl. 19,
figs. 1-6, 1911. For a discussion of this species see Dodge, Bull.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Amer. Mus. Nat. Hist., Vol. 100, Art. 1, p. 85, 1952].

(957) See Keen, A. M., Veliger, Vol. 4, No. 4, pp. 179-180, 1962.
(958) Notirus Finlay, Trans. Proc. New Zealand Inst., Vol. 59,
Pt. 2, p. 278, issued August 31, 1928. A new name for Jrona Fin-
lay, 1926. Not Irona Mabille, 1883; not Irona Schiddte & Meinert,
1884.

(959) Paphonotia Hertlein and Strong, Zoologica, Vol. 33, Pt. 4,
No. 13, p. 192, December 31, 1948. “Type: Petricola elliptica Sow-
erby, 1834.” Illustrated by Keen, Sea Shells of Tropical West
America (Stanford Univ. Press: Stanford, California), p. 188, fig.
318, 1958.

(960) This species was reported from beds of Pleistocene age at
Punta China, Lower California (see Emerson, W. K., Bull. Amer.
Mus. Nat. Hist., Vol. 111, Art. 4, p. 339, 1956).

(961) Irus lamellifer (Conrad) variety prelamellifer Grant and
Gale, Mem. San Diego Soe. Nat. Hist., Vol. 1, p. 332, pl. 18, fig. 7,

November 3, 1931. “Pacific Eastern Production Company’s well -

No. 1, KCL-B, See. 21, T. 29S., R. 27 E., Fruitvale District, Kern
County, near Bakersfield, California, depth 4859 feet, upper
(possibly middle) Miocene.”

(962) See Venerupis multicostata Turton, Mar. Shells of Port
Alfred, South Africa, p. 245, No. 1731, pl. 66, fig. 1731, 1932.

(963) Chione lordi Baird, Proce. Zool. Soc. London for 1863, p. 69,
February 10, 1863. ‘Hab. Esquimalt Harbour, Vancouver Island.
(Mus. Brit.).” “This shell was taken in considerable numbers
from the crop of a Pin-tail Duck. . .”—Dall, Proc. U.S. Nat. Mus.,
Vol. 26, No. 1312, pp. 401, 407, pl. 16, figs. 5, 6, 1902 (as Psephidia
lordi). (Copy of Dall’s illustration by I. S. Oldroyd, 1924, pl. 6, fig.
3.)—Grant and Gale, Mem. San Diego Soc. Nat. Hist., Vol. 1, p.
336, pl. 15, figs. 5, 6, 7a, 7b, 1931 (as Psephidia lordi Baird).

(964) Psephidia cymata Dall, Proc. U.S. Nat. Mus., Vol. 45, No.
2002, p. 593, June 11, 1918. “Near Cerros Island, Lower Califor-
nia, in shallow water.”—Dall, U.S. Nat. Mus., Bull. 112, p. 44, pl.
3, fig. 2, 1921. “Santa Barbara Islands, California, to the Gulf of
California.”

(965) See Woodring, W. P., in Woodring et al., U.S.G.S., Prof.
Paper 195, pp. 94, 95, pl. 24, figs. 4-6, 1940 (1941).

(966) See Psephidia salmonea Carpenter, K. V. W. Palmer,
Geol. Soc. Amer. Mem. 76, p. 99, pl. 11, figs. 6-12, 1958. “Recent.
Catalina Island, California, 30 fathoms (type).”

(967) See Keen, A. M., and Bentson, H., Geol. Soc. Amer., Spec.
Papers No. 56, pp. 104, 121, 1944.

(968) Venus rhysomia Gabb, Proc. Acad. Nat. Sci. Philadelphia,
Vol. 13, p. 369, November, 1861. ‘‘From Santa Barbara, Cal. Mio-
cene (?).”

(969) See Woodring, W. P., Bramlette, M. N., and Kew, W. S.
W., “Geology and Paleontology of Palos Verdes Hills, Califor-
nia,” U.S.G.S., Prof. Paper 207, p. 27, 1946.

(970) Woodring, W. P., in Woodring, W. P., and Bramlette, M.
N., “Geology and Paleontology of the Santa Maria District, Cali-
fornia,” U.S.G.S., Prof. Paper 222, p. 90, 1950.

(971) Martin, B., in Lawson, A. C., U.S.G.S., Folio 193, p. 14,
1914 (as Transennella tantilla Carpenter).

(972) Martin, B., ‘The Pliocene of Middle and Northern Califor-
nia,’ Univ. Calif. Publ. Bull. Dept. Geol., Vol. 9, No. 15, p. 254,
1916.

(973) Stewart, R. B., in Woodring, W. P., Stewart, R. B., and
Richards, R. W., “Geology of the Kettleman Hills Oil Field, Cali-
fornia, “U.S.G.S., Prof. Paper 195, p. 94, 1940 (1941).

(974) Transennella californica Arnold, U.S.G.S., Bull. 396, p. 72,
pl. 26, figs. 7, 7a, 1909 (January 15, 1910). “United States Geologi-
cal Survey locality 4715, south end of Kettleman Hills, sec. 10, T.
25 S., R. 19 E.” “Upper Etchegoin formation, upper Miocene.”
[Pliocene. }

(975) Hansen, B., “Brood Protection and Sex Ratio of Trans-
ennella tantilla (Gould), a Pacific Bivalve,” Vidensk. Medd.
Dansk. Naturhist. Kébenhavn, Bd. 115, pp. 313-324, figs. 1-4, 1953.
(976) Cited as Famille Petricolidae by d’Orbigny, in Webb and

371

Berthelot, Hist. Nat. Iles Canaries, Vol. 2, Pt. 2, Moll., p. 109, 1887.
(977) See Keen, A. M., in Burch, J. Q., Min. Conch. Club South.
California, No. 42, p. 18, December, 1944.

(978) Lamy, E., “Révision des Petricola vivants du Muséum Na-
tional d’Histoire Naturelle de Paris,” Jour. de Conchyl., Vol. 67,
No. 4, pp. 334-337, 1923.

(979) Petricola pedroana Conrad, House Document 129, Pro}.
Vol. 3, 33rd Congress, Ist Session, p. 18, July, 1855. “Occurs with
the preceding shell” [that is Saxicava abrupta] from “San Pedro.
Recent formation.””—Conrad, U.S. Pac. Railroad Expl., Vol. 5, p.
324, pl. 3, fig. 24, 1857.

(980) Petricola (Petricola) lucasana Hertlein and Strong, Zoo-
logica, Vol. 38, Pt. 4, No. 18, p. 194, pl. 2, figs. 4, 9, December 31,
1948.

(981) Petricola buwaldi B. L. Clark, Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 8, No. 22, p. 471, pl. 60, fig. 6, August 30, 1915. “Up-
per San Pablo Group to the southeast of the town of Walnut
Creek, University of California locality 1942.”

(982) Yonge, C. M., “Observations on Petricola carditoides (Con-
rad),”’ Proc. Malacol. Soe. London, Vol. 33, Pt. 1, pp. 25-31, pl. 4,
figs. 1-3 in text, March, 1958.

(983) Cited as “Familie” “Tellinaceae” by Oken, 1818. Also cited
as ‘‘Family 9, is the Tellinae or Tellens,” by Da Costa, 1776; and as
“les tellinacées,” by Blainville, 1814.

(984) Yonge, C. M., “On the structure and adaptations of the
Tellinacea, deposit-feeding Eulamellibranchia,” Philos. Trans.
Roy. Soe. London, Ser. B, Biol. Sci., No. 609, Vol. 234, pp. 29-76, figs.
1-29 in text, September 5, 1949.

(985) See remarks on the geologic range of this family by Chavan
(Bull. Inst. Roy. Sci. Nat. Belgique, Vol. 26, No. 11, pp. 4, 16, 1950).
(986) Dall, W. H., “Synopsis of the family Tellinidae and of the
North American species,” Proc. U.S. Nat. Mus., Vol. 28, No. 1210,
pp. 285-326, pls. 2-4, November 14, 1900. See also a systematic ar-
rangement of the Tellinacea by Keen in “Treatise on In-
vertebrate Paleontology” (Geol. Soe. Amer. and Univ. Kansas),
Part N, Vol. 2, pp. N613-N643, figs. E104-E124, 1969.

(987) Salisbury, A. E., “On the Nomenclature of Tellinidae, with
descriptions of new species and some remarks on distribution,”
Proc. Malacol. Soc. London, Vol. 21, pt. 2, pp. 74-91, pls. 9-14, July,
1934.

(988) Hertlein, L. G., and Strong, A. M., “Eastern Pacific Expedi-
tions of the New York Zoological Society. XL. Mollusks from the
west coast of Mexico and Central America. Part VII.” Zoologica,
Vol. 34, Pt. 2, pp. 63-97, pl. 1, August 10, 1949.

(989) Keen, A. M., Sea Shells of Tropical West America (Stan-
ford Univ. Press: Stanford, California), pp. 162-184, 1958.

(990) Olsson, A. A., Mollusks of the Tropical Eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), pp. 375-419, 1961.

(991) Boss, K.J., The subfamily Tellinae in the western Atlantic.
The genus Tellina (Part 1), Johnsonia, Vol. 4, No. 45, pp. 217-272,
pls. 127-142, October 31, 1966; the genera Tellina (Part II) and
Tellidora, vol. 4, No. 46, pp. 273-344, pls. 143-163, April 17, 1968.—
See also, ‘Taxonomic revision of the super-specific groups of the
Cretaceous and Cenozoic Tellinidae,” by F. Afshar, with an ap-
pendix by H. A. Rehder. (Geol. Soc. Amer., Mem. 119, pp. I-XI, 1-
215, pls. 1-45, 1969) and review by K. J. Boss (Jour. Paleo., Vol. 45,
No. 3, pp. 558-560, May, 1971). [Pages 97-107, pls. 42-45, are by H.
A. Rehder.]

(992) Not represented in the present collections.

(993) Reported from San Diego Formation but not represented
in the present collections.

(994) See Fleming, C. A., Trans. Proc. Roy. Soc. New Zealand,
Vol. 79, Pt. 1, p. 184, 1951.

(995) See Burch, J. Q., Min. Conch. Club South. Calif., No. 48, p. 6,
January, 1945.

(996) Tellina nevadensis Anderson and Martin, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 4, p. 61, pl. 2, figs. 3a, 3b, 3c, December 30,
1914. “The type specimen was obtained from the lower Miocene

372

of Kern River, California, locality 65.” Fig. 3b, from Loc. 126
(CAS), “In bed of small creek, near the center of Sec. 34, T. 28S.,
R. 15 E., San Luis Obispo County, California.”

(997) See Stewart, R. B., U.S.G.S., Prof. Paper 205c, pp. 100, 102,
also table 2 (as Tellina cf. idae), 1946.

(998) See Woodring, W. P., Bull. Amer. Assoc. Petrol. Geol., Vol.
20, No. 2, p. 138, 1936.

(999) See Moore, Ellen J., U.S.G.S., Prof. Paper 419, p. 79, pl. 29,
figs. 1-5, 1963.

(1000) Tellina tenuilineata Clark, Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 11, No. 2, p. 153, pl. 10, figs. 1, 3, 5, July 16, 1918. “Out-
crop in bed of creek about one-half mile south and a little west of
the town of Walnut Creek.” San Lorenzo series, Oligocene.
(1001) Tellina englishi Clark, Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 8, No. 22, p. 472, pl. 61, figs. 6, 7. August 30, 1915.
“From the Upper San Pablo Group on the south side of Mount
Diablo, University of California locality 481.”

(1002) See Loel, W., and Corey, W. H., Univ. Calif. Publ. Bull.
Dept. Geol. Sci., Vol. 22, No. 3, p. 147, 1932.

(1003) Tellina tenuistriata Davis, Jour. Geol., Vol. 21, No. 5, p.
457, fig. 7, July-August, 1913. “From the Lower Temblor on the
northern San Antonio headwaters, Monterey County, Cal.” Ac-
cording to Keen and Bentson, 1938 (p. 116), this locality is in Sec.
21, T. 21S., R. 5 E., Junipero Serra quadrangle, Monterey Co.,
California. This species was renamed Tellina insurana by G D.
Hanna (Proc. Calif. Acad. Sci., Ser. 4, Vol. 18, No. 10, p. 183,
March 18, 1924). Also renamed Tellina davisi by Salisbury, 1934.
(1004) Semelangulus Iredale, Proc. Linn. Soe. New South
Wales, Vol. 49, Pt. 3, p. 212, October 24, 1924. “with this species
as type,” Tellina tenuilirata Sowerby, 1867.

(1005) See Kanehara, K., Jap. Jour. Geol. Geogr., Vol. 18, No. 4,
p. 138, pl. 16 [not pl. 15 as indicated], fig. 7, December 10, 1942.
Setana Series of Hokkaido. A
(1006) See Hatai, K., and Nisiyama, S., Sci. Repts. Tokohu
Univ., Sendai, Japan, Second Ser. (Geol.), Spec. Vol. No. 3, p. 141,
1952.

(1007) Tellina kesenensis Nomura and Hatai, Saito Ho-on Kai
Mus., Res. Bull. No. 5, p. 14, pl. 1, figs. la, 1b, 1935. ““Hanagai,”
northeast Honsyd, Japan, Recent.

(1008) See Habe, T., Gen. Jap. Shells, Pelecypoda, No. 3, p. 212,
1952.

(1009) Tellina (Peronidia) solmonaeformis Nomura and Hatai,
Saito Ho-On Kai Mus., Res. Bull. No. 19 (Geology No. 7), p. 84, pl.
4, figs. 12a, 12b, July, 1940. Kydroku-sima, Japan, Recent.

(1010) See Boss, K. J., Johnsonia, Vol. 4, No. 46, pp. 300-327, pls.
152-159, 1968.

(1011) See Eames, F. E., Philos. Trans. Roy. Soc. London, Ser.
B, No. 627, Vol. 235, p. 396, 1951.

(1012) Tellina (Moerella) arenica Hertlein and Strong, Zoolog-
ica, Vol. 34, Pt. 2, p. 68, pl. 1, figs. 5, 11, August 10, 1949. “dredged
at station 136-D-20 in Lat. 23°30/N., Long. 109°26’W., in 43 fath-
oms, mud, on Arena Bank, at the south end of the Gulf of Cali-
fornia.”

(1013) Tellina (Peronidia) nitida Poli, Cossmann and Peyrot,
Act. Soc. Linn. Bordeaux, Vol. 64 (Conch. Néog. de |’Aquitaine,
Tome 1, Livr. 2), p. 244, pl. 9, figs. 6, 7, 1911.

(1014) Tellina (Peronidia) santarosae Dall, Proc. U.S. Nat.
Mus., Vol. 23, No. 1210, p. 321, pl. 3, fig. 6; pl. 4, figs. 1, 2, Novem-
ber 14, 1900. “Collected at Santa Rosa Island, of the Santa Bar-
bara group, California, by Stephen Bowers.”

(1015) See Tellina (Peronidia) bodegensis Hinds n. subspecies?,
Clark and Arnold, Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol.
14, No. 5, p. 149, pl. 22, figs. 7, 8, November 6, 1928. Loc. 231
(CAS), “In the sea cliffs east of the mouth of Kirby Creek, 6
miles west of Sooke, Vancouver Island.”

(1016) See Oinomikado, T., On the pallial sinus of the genus
Macoma,” Venus, Vol. 4, no. 6, pp. 353-356, pl. 8, and figs. 1-11 in
text, 1934.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(1017) Tellina moesta Deshayes, Proc. Zool. Soc. London for
1854, p. 361 (issued May 16, 1855). “Hab. Northern Ocean. Coll.
Cuming.” For an illustration see Macoma krausei Dall, Proce.
U.S. Nat. Mus., Vol. 23, No. 1210, p. 307, pl. 4, fig. 8, November 14,
1900. “Iey Cape, Arctic Ocean.” Illustration reproduced by Grant
and Gale, 1931, pl. 20, fig. 3. See also MacGinitie, Proc. U.S. Nat.
Mus., Vol. 109, No. 3412, p. 182, pl. 21, figs. 1-3; pl. 28, fig. 10; pl.
24, figs. 1-3, 1959.

(1018) Madsen, F. J., Zool. Iceland, Vol. 4, No. 63, p. 72, 1950.
(1019) See Gould, A. A., “Report on the Invertebrata of Mas-
sachusetts,” ed. by W. G. Binney (Boston), p. 95, fig. 401, 1870.
See also Tellina proxima Sowerby, Dunnill and Coan, 1968, figs.
Tex:

(1020) MacNeil, F. S., “Cenozoic Fossils of Northern Alaska,”
U.S.G.S., Prof. Paper 294-C, p. 106, 1957.

(1021) Hatai, K., and Nisiyama, S., “Checklist of Japanese Ter-
tiary Marine Mollusca,” Sci. Repts. Tohoku Univ., Sendai, Japan,
Second Ser. (Geol.), Spec. Vol. No. 3, p. 81, 1952.

(1022) Macoma calcarea yokohamaensis Aoki, Trans. Proc.
Palaeo. Soc. Japan, New Ser., No. 39, p. 305, pl. 34, figs. 15-17, text
fig. 2, September 1, 1960.

(1023) See Macoma (Macoma) calcarea Gmelin, Malatesta,
Serv. Geol. D’Italia, Mem. Carta Geol. D’Italia, Vol. 12, Pt. 2, pp.
305-308, pl. 19, fig. 4, and fig. 18 in text, 1963.

(1024) See Soot-Ryen, T., Norwegian north Polar Exped. with
the “Maud” 1918-1925, Sci. Results, Vol. 5, No. 12, p. 17, pl. 2,
figs. 1, 2, 3 (Macoma calcarea forma longisinuata), figs. 4, 5, 6
(Macoma calcarea forma obliqua), 1932 (not Tellina obliqua
Wood, 1815; not T. obliqgua J. Sowerby, 1817).

(1025) Odhner, N. H-J., K. Svensk. Vet. Akad. Handl., Bd. 54,
No. 1, p. 107, 1915. See also Ockelmann, W. R., Medd. om Grén-
land, Bd. 122, No. 4, p. 125, pl. 2, fig. 10, 1958.

(1026) MacGinitie, N., Proc. U.S. Nat. Mus., Vol. 109, No. 3412,
p. 181, pl. 24, figs. 5-7; pl. 26, figs. 6-9, 1959.

(1027) Macoma affinis plena Stewart, in Woodring, W. P., Stew-
art, R., and Richards, R. W., U.S.G.S., Prof. Paper 195, p. 93, pl.
29, fig. 12; pl. 39, fig. 3; also “ef.” pl. 15, fig. 18 and pl. 24, fig. 3,
1940 (issued June 7, 1941). Type locality 238a (USGS), “60 feet
stratigraphically above locality 238.” which is “Sec. 20, T. 22 S.,
R. 18 E.; 2,390 feet north, 2,680 feet east; east side of El Leon.”
“Littorina zone, Etchegoin formation.”

(1028) Tellina irus Hanley, Proc. Zool. Soc. London for 1844, p.
166 (issued February, 1845). ‘‘Hab—? Mus. Cuming, Walton.”—
Hanley, Thes. Conch., Vol. 1, Tellina, p. 319, pl. 60, fig. 145, 1846.
“Guinea?”

(1029) Salisbury, A. E., “On the Nomenclature of Tellinidae,
with Descriptions of New Species and Some Remarks on Distri-
bution.” Proc. Malacol. Soc. London, Vol. 21, Pt. 2, p. 85, pl. 12,
figs. 5-8, July 14, 1934.

(1030) Tellina contabulata Deshayes, Proc. Zool. Soc. London
for 1854, p. 356 (issued May 16, 1855). “Hab. Chinese Seas. Coll.
Cuming.”—Sowerby, Conch. Icon., Vol. 17, Tellina, sp. 311, pl. 52,
fig. 311, 1868.

(1031) Keen, A. M., “Reinstatement of the specific name Ma-
coma inquinata (Deshayes),” Veliger, Vol. 4, No. 3, p. 161, Janu-
ary 1, 1962.

(1032) Macoma anser Oyama, Min. and Geol., Vol. 6, No. 3, p. 3,
November 10, 1950.—Kira, Coloured Illustrations of the shells of
Japan (revised ed.: Hoikusha, Japan), p. 155, pl. 59, fig. 20, 1959.
(1033) Macoma inquinata new variety arnheimi Dall, Proce.
U.S. Nat. Mus., Vol. 52, No. 2183, p. 414, December 27, 1916. “Ko-
diak Island, Alaska.” Illustrated by I. S. Oldroyd, Stanford Univ.
Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 172, pl. 42, fig. 9 (as Macoma
inquinata), 1924.

(1034) Macoma inquinata affinis Nomland, Univ. Calif. Publ.
Bull. Dept. Geol. Sci., Vol. 10, No. 14, p. 233, pl. 9, figs. 1, la, 1b,
April 19, 1917. “Locality 2965, Mya japonica zone, uppermost Et-
chegoin.” See also discussion by R. B. Stewart, U.S.G.S., Prof.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Paper 195, p. 93, 1940 (1941).
(1035) See Carole J. S. Hickman, Mus. Nat. Hist. Univ. Oregon,
Bull. No. 16, p. 58, pl. 6, fig. 20; pl. 7, figs. 1, 2, August, 1969. Eu-
gene Formation.
(1036) Macoma tokyoensis Makiyama, Mem. Coll. Sci. Kyoto
Imper. Univ., Ser. B, Vol. 3, No. 1, p. 50 (footnote), March, 1927.
“proposed for the preoccupied name M. dissimilis (Martens)
(Yokoyama, Foss. Miura Penin., p. 116, pl. 7, f. 19, 20).” See also
Oinomikado, T., Venus, Vol. 4, No. 6, p. 355, figs. 2, 3, in text, pl.
8, figs. 12, 18 (M. tokyoensis), 1934.
(1037) Kanehara, K., Trans. Proc. Palaeo. Soc. Japan, No. 8
(Jap. Jour. Geol. Soc., Vol. 44, Nos. 526-528), p. 703 (104), 1937.
(1038) See Hatai, K., and Nisiyama, S., Sci. Repts. Tohoku
Univ., Sendai, Japan, Second Ser. (Geol.), Special Vol. No. 3, pp.
81-83, 462, 1952.
(1039) Macoma aomoriensis Nomura, Saito Ho-On Kai Mus.,
Res. Bull. Vol. 6, p. 63, pl. 4 (3), figs. 3, 4, 5, September, 1935.
Northeast Honsy4, Japan, early Miocene.
(1040) Macoma ishimoriensis Aoka, Sci. Repts. Tokyo Kyoiku
Daigaku, Sec. C, Vol. 3, No. 17, p. 37, pl. 2, fig. 21, March 27, 1954.
Kabeya formation, Miocene.
(1041) Slodkewitsch, W. S., Paleo. of USSR (Acad. Sci. USSR),
Vol. 10, Pt. 3, Fasc. 18, p. 460, Fase. 19, p. 170, pl. 95, figs. 8, 8a, 9,
1938. Kavrana series. Kamtschatka, Pliocene.
(1042) See Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 34,
Pt. 2, p. 89, 1949.
(1043) See Addicott, W., and Emerson, W. K., Amer. Mus. Novi-
tates, No. 1925, pp. 17, 21, 1959.
(1044) See Berry, S. S., Jour. Conch., Vol. 24, No. 3, p. 83, 1956.
Reported from Punta Pefiasco, Sonora, Mexico, by Lowe, 1935.
(1045) Macoma (Rexithaerus) indentata flagleri Etherington,
Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol. 20, No. 5, p. 85, pl.
10, figs. 3, 4, May 20, 1931. From U.C. Loe. 9017 [According to
Weaver, 1943, p. 211, the type is from “cut of abandoned spur of
Clemons logging road one-fourth mile north of main line in the
first large cut in Section 23, T. 17 N., R. 7 W.”]
(1046) Macoma vanvlecki Arnold, U.S.G.S., Bull. 396, p. 65, pl.
12, fig. 2; pl. 16, fig. 1, 1909 (issued January 15, 1910). ‘200 yards
north of Jacalitos Creek crossing Stone Canyon—Coalinga road,
14 miles southwest of Coalinga.” Jacalitos, Lower Pliocene.
(1047) See Nomland, J. O., Univ. Calif. Publ. Bull. Dept. Geol.,
Vol. 10, No. 14, pl. 8, fig. 3, 1917.
(1048) Macoma moliniana Dall, U.S.G.S., Prof. Paper 59, p. 128,
pl. 14, fig. 12, April 2, 1909. “Collected from the Oligocene (?)
sandstones at Millers Beach, by W. H. Dall.”
(1049) See Weaver, C. E., Univ. Washington Publ. Geol., Vol. 5,
p. 212, pl. 49, fig. 15, 1942 (1948).
(1050) See Macoma indentata Carpenter, Simonova, Trans.
Geol. Oil Inst., New Ser. Fase. 18, p. 46, pl. 20, figs. 4, 5, 1941.
(1051) See Macoma aff. indentata Carpenter subsp. tenui-
rostris Dall, Faustman, Univ. Calif. Publ. Geol. Sci., Vol. 41, No.
2, p. 122, pl. 1, fig. 12, 1964.
(1052) See Kanakoff, G. P., and Emerson, W. K., Contrib. Sci.
Los Angeles Co. Mus., No. 31, p. 23, 1959.
- (1053) See Willett, G., Trans. San Diego Soe. Nat. Hist., Vol. 8,
_ No. 30, p. 390, 1937.
- (1054) Metis H. and A. Adams, Gen. Ree. Moll., Vol. 2, p. 399,
_ November, 1856. Sole species, “Meyeri, Phil.” [See Tellina
~ meyeri Dunker in Philippi, Abbild. u. Beschreib. Conchyl., Bd. 2,
_ Heft 4, p. 89 (21), Tab. 4, fig. 1, August, 1846. “Patria: Indiae ori-
_ entales.”] Not Metis Philippi, 1843. Crustacea. Not Metis Gistl,
_ 1848. Echinodermata.
~ (1055) Polymetis A. E. Salisbury, Proc. Malacol. Soc. London,
_ Vol. 18, Pt. 5, p. 255, July 15, 1929. “I therefore propose the name
_ Polymetis, with type meyeri, Dkr., for the group in question.”
_ Not Polymetis Walsingham, 1903. Insecta.
- (1056) Apolymetis A. E. Salisbury, Proc. Malacol. Soe. London,
_ Vol. 18, Pt. 6, p. 258, November, 1929. A new name for Polymetis

|

373

Salisbury, 1929, (not Polymetis Walsingham, 1903), “with the
same type, Tellina meyeri, Philippi.”

(1057) Hemimetis Thiele, Handbuch der Systematischen Weich-
tierkunde, Bd. 2, Teil 3, p. 915, 1934. Sole species, “A. (H.) plicata
Valenciennes.”

(1058) Psammotreta Dall, Proc. U.S. Nat. Mus., Vol. 23, No.
1210, p. 292, November 14, 1900. “Type, Tellina aurora Hanley.”
(1059) See Apolymetis ef. A. sespeensis (Loel and Corey),
Weaver and Kleinpell, Univ. Calif. Publ. Geol. Sci., Vol. 43, p.
207, pl. 38, fig. 2, March 28, 1963. “Undifferentiated Gaviota for-
mation.”

(1060) See Macoma constricta Bruguiére, M. Smith, East Coast
Marine Shells, Ed. 3, (Edwards Bros.: Ann Arbor, Michigan). p.
59, pl. 2, fig. 9, 1945. North Carolina to Brazil, Recent.

(1061) Lutricola cognata Pilsbry and Vanatta, Proc. Washing-
ton Acad. Sci., Vol. 4, p. 556, pl. 35, fig. 5, September 30, 1902.
“From Tagus Cove, Albemarle.” Galapagos Islands.

(1062) Apolymetis clarki Durham, Geol. Soc. Amer., Mem. 43,
Pt. 2, p. 90. pl. 24, fig. 12; pl. 25, fig. 14, August 10, 1950. Loc. A-
3582 = Pleistocene, Santa Inez Bay, Lower California. From 20-
foot terrace level extending from loc. A-3581 to beach.

(1063) See discussion by Hertlein, L. G., and Strong, A. M., Zoo-
logica, Vol. 34, Pt. 2, p. 93-94, August 10, 1949.

(1064) See Metis alta Conrad, Khomenko, Trans. Geol. Oil Inst.,
Ser. A, Fasc. 103, p. 78, pl. 14, fig. 1, 1938. Schmidt Peninsula,
Kamtschatka. “Machigar section.”

(1065) Keen, A. M., Veliger, Vol. 8, No. 3, p. 170, January 1,
1966.

(1066) See Deshayes, G. P., Proc. Zool. Soe. London for 1854, p.
354, issued May 16, 1855.

(1067) Cited as “Sub-fam.,—Semelinae,” by Stoliezka, 1871, and
as “Family 34. Semelidae” by Dall, in 1895. In earlier literature
included (at least in part) in “Amphidesmidae;” “Family VII.
Amphidesmadae” of Leach, 1852; ‘““Sub-fam. Scrobiculariinae” of
H. and A. Adams, 1856; and Family Scrobiculariadae by E. Gray,
1857.

(1068) See Yonge, C. M., Philos. Trans. Roy. Soc. London, Ser.
B, Biol. Sci., No. 609, Vol. 234, p. 35, September, 1949.

(1069) See Lamy, E., “Révision des Scrobiculariidae vivants du
Muséum d'Histoire Naturelle de Paris,” Jour. de Conchyl., Vol.
61, No. 3, pp. 243-368, pl. 8, 18 figs. in text, March, 1914.

(1070) See Dall, W. H., “Notes on the Semelidae of the West
Coast of America, including some new species,” Proc. Acad. Nat.
Sci. Philadelphia, Vol. 67, pp. 25-28, March 2, 1915.

(1071) See Hertlein, L. G., and Strong, A. M., “Eastern Pacific
Expeditions of the New York Zoological Society. XLI. Mollusks
from the west coast of Mexico and Central America. Part VIII,”
Zoologica, Vol. 34, Pt. 4, pp. 239-258, pl. 1, December 30, 1949. (Se-
mele, pp. 239-249).

(1072) See Keen, A. M., Sea Shells of Tropical West America
(Stanford Univ. Press: Stanford, California), pp. 194-202, 1958.
(1073) See Olsson, A. A., Mollusks of the Tropical Eastern Paci-
fic (Paleo. Res. Inst.: Ithaca, New York), pp. 358-375, 1961.
(1074) Cumingia? antiquata Philippi, Los Fésiles Terciarios I
Cuartarios de Chile, p. 151, pl. 28, fig. 10, 1887. “Cerca de Levu,”
Chile.

(1075) See von Ihering, H., An. Mus. Nac. Buenos Aires, Ser. 3,
Vol. 7, p. 316, 1907.

(1076) Deshayes, M., “Note sur l’animal des Cumingia,” Jour.
de Conchyl. Vol. 5, pp. 278-282, 1856.

(1077) Grave, B. H. “The Natural History of Cumingia tell-
inoides,” Biol. Bull., Vol. 58, No. 3, pp. 208-219, 1927.

(1078) See Lamy, E., Jour. de Conchyl., Vol. 61, No. 3, pp. 306-
314, 2 figs., 1914.

(1079) See Strong, A. M., in Burch, J. Q., Min. Conch. Club
South. California, No. 43, p. 19, January, 1945.

(1080) Cumingia lamellosa Sowerby, Proc. Zool. Soc. London
for 1833, p. 34, issued May 17, 1833. “Hab. prope littora Oceani

374

Pacifici.” “Found at Payta in hard clay at low water; and at Pan-
ama in deep water.’’—Sowerby, Reeve’s Conch. Icon., Vol. 19, Cu-
mingia, species 5, pl. 1, fig. 5, 1873. “Hab. Chile.”—Hertlein and
Strong, Zoologica, Vol. 34, Pt. 4, p. 250, 1949. “San Martin Island,
Lower California, to the Gulf of California and south to Paita,
Peru.”—Olsson, Moll. Trop. East. Pacific (Paleo. Res. Inst.: Ith-
aca, New York), p. 371, pl. 66, figs. 10, 10a; pl. 67, figs. 3, 3a, 1961.
“Gulf of California to northern Peru.”

(1081) Thyella lamellosa H. Adams, Proc. Zool. Soc. London for
1873, p. 208, pl. 23, fig. 15. “Hab. Mauritius (coll. H. Ad.).”

(1082) See Yonge, C. M., Phil. Trans. Roy. Soc. London, Ser. B,
Biol. Sci., No. 609, Vol. 234, pp. 38-40, September, 1949.

(1083) See Chavan, A., Bull. Soc. Géol. France, Ser. 5, Vol. 6,
Nos. 6, 7, 8, pp. 447-450, 1936. See also Bull. Inst. Roy. Sci. Nat.
Belgique, Vol. 36, No. 11, pp. 9-10, 1950.

(1084) See Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 34,
Pt. 4, pp. 251-258, pl. 1, December 30, 1949.

(1085) See Keen, A. M., Sea Shells of Tropical West America
(Stanford Univ. Press: Stanford, California), pp. 184-186, 1958.
(1086) See Olsson, A. A., Mollusks of the Tropical Eastern Paci-
fic (Paleo. Res. Inst.: Ithaca, New York), pp. 336-347, 1961.
(1087) See Notodonax Feruglio, Mem. Inst. Geol. Univ. Padova,
Vol. 11, No. 3, p. 125, 1936. Sole species, Donax (Notodonax)
anna-eugeniae Feruglio.

(1088) Protodonax Vokes, Jour. Paleo., Vol. 19, No. 3, p. 295,
May, 1945. Type species, Protodonax elongatus Vokes.

Eodonax Cox (Ann. Mag. Nat. Hist., Ser. 10, Vol. 3, No. 18, p.
584, June, 1929, type, Hodonax dukei Morris and Lycett, late Ju-
rassic), is a member of the family Tancrediidae.

(1089) See Donax gracilis Hanley, Hertlein and Strong, Zoolog-
ica, Vol. 34, Pt. 4, p. 253, pl. 1, figs. 4, 6, 1949.

(1090) Fitch, J. E., State Calif. Dept. Fish Game, Mar. Fish.
Branch, Fish Bull. No. 90, p. 85, fig. 51, 1953. f
(1091) Coe, W. R., “Ecology of the Bean Clam Donax gouldi on
the coast of southern California,” Ecol., Vol. 36, No. 3, pp. 512-
514, figs. 1 and 2, 1955. See also, Univ. California Scripps Inst.
Oceanogr., Contrib. for 1955, No. 787, pp. 605-608.

(1092) Cited as Subfamily Garinae by Stoliezka, 1871. [The fam-
ily Garidae as used here also has also been cited by various au-
thors as family Psammobiidae Fleming, Hist. Brit. Anim., p.
437, 1828 (as ‘““Psammobiadae.’”’)]

(1093) Dall, W. H., “Synopsis of the Recent and Tertiary
Psammobiidae of North America,” Proc. Acad. Nat. Sci. Phila-
delphia, Vol. 50, pp. 57-62, mailed April 5, 1898.

(1094) Not represented in the fauna of the San Diego Forma-
tion.

(1095) Gari Schumacher, Essai Nouv. Syst. Test., p. 181, pl. 9,
fig. 2, 1817. Ref. to ‘‘Tellina gari Lin. Spengl. |. c. 4. H. 2. pag. 70.
No. 1. Chemn. 6. pag. 100. Tab. 10. fig. 92, 93.”

(1096) Stewart, R. B., Acad. Nat. Sci. Philadelphia, Spec. Publ.
No. 3, p. 280, 1930.

(1097) Dodge, H., Bull. Amer. Mus. Nat. Hist., Vol. 100, Art. 1,
pp. 42-43, 1952.

(1098) Cox, L. R., Bull. Zool. Nomencl., Vol. 22, Pt. 3, pp. 144-145,
1965.

(1099) Lemche, H., and Parker, R. R., Bull. Zool. Nomencl., Vol.
19, Pt. 6, pp. 375-377, pl. 6, figs. 1-4, 1962.

(1100) See Opinion 910 in Bull. Zool. Nomencl., Vol. 27, Pt. 1, p.
16, June 5, 1970.

(1101) Solen amethystus Wood, Gen. Conch., p. 138, pl. 34, fig. 1,
1815; also ed. 1825. “Inhabits India.’’—Reeve, Conch. Icon., Vol.
10, Psammobia, sp. 19, pl. 3, fig. 19, 1865. Hab. Ceylon.

(1102) Psammobia Lamarck, Hist. Nat. Anim. s. Vert., Vol. 5, p.
511, July, 1818. Type (designated by Children, Quart. Jour. Sci.,
Vol. 14, p. 304, 1828): P. feroensis (Tellina fereonsis Gmel.).—
Dall, Proc. Acad. Nat. Sci. Philadelphia, Vol. 50, p. 57, 1898.
“Type P. (Tellina) feroénsis Gmelin, 1792, = T. gari Lin., 1762,
not of Lin., 1758. North European Seas.”

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(1103) See Rollier, L., Abhandl. Schweiz. Palaont. Gesell., Vol.
39, pp. 266-268, 1913.

(1104) See Gardner, J., Geol. Soc. Amer., Mem. 11, p. 109, 1945.
(1105) See Finlay, H. J., and Marwick, J., Trans. Roy. Soc. New
Zealand, Vol. 70, Pt. 1, p. 108, 1940.

(1106) See Davies, A. M., Tertiary Faunas (Thomas Murby &
Co.: London), Vol. 1, p. 144, 1935.

(1107) Yonge, C. M., Philos. Trans. Roy. Soc. London, Ser. B,
Biol. Sci., No. 609, Vol. 234, see especially pp. 40-41, fig. 6, Sep-
tember 5, 1949.

(1108) See Psammobia aff. edentula Gabb, Clark, Univ. Calif.
Publ. Bull. Dept. Geol., Vol. 11, No. 2, p. 155, pl. 16, fig. 3, 1918.
(1109) Tellina fucata Hinds, Zool. Voy. Sulphur, Moll., Pt. 3, p.
67, pl. 21, fig. 4, 1844 (January, 1845). ““Inhab. Bay of Magdalena,
California.”—Keen, Veliger, Vol. 8, No. 4, p. 268, pl. 46, fig. 4,
April 1, 1966. (Holotype.)

(1110) See Ghosh, E., Rec. Indian Mus., Vol. 19, Pt. 2, pp. 67-72,
1920.

(1111) Gardner, J., stated that Tagelus occurs in strata of Cre-
taceous age (see U.S.G.S., Prof. Paper 142-K, p. 214, 1928), but
this record needs confirmation.

(1112) See Hesse, R., Ecological animal Geography (ed. by Al-
lee, W. C., and Schmidt, K. P.) (John Wiley and Sons, New York),
p. 167, 1937.

(1118) Bloomer, H. H., “On the anatomy of Tagelus gibbus and
T. divisus,” Proc. Malacol. Soe. London, Vol. 7, No. 4, pp. 218-223,
pl. 19, 1907.

(1114) See Subtagelus Ghosh, Rec. Indian Mus., Vol. 19, Pt. 2,
No. 11, pp. 71, 72, June 3, 1920. “A separate subgenus (Subta-
gelus) is suggested for this species [that is, T. divisus] in the
present paper” (p. 71).

(1115) See Keen, A. M., Marine Molluscan Genera of western
North America (Stanford Univ. Press: Stanford, California), p.
92, 1963.

(1116) Reported from Panama by authors but not reported
from that region by Olsson (Mollusks of the Tropical Eastern
Pacific, Paleont. Res. Inst.: Ithaca, New York, 1961).

(1117) See Min. Conch. Club South. California, No. 190, p. 22,
July-August, 1959.

(1118) See Kellog, J. L., Ciliary Mechanisms of Lamellibranchs
with descriptions of anatomy,” Jour. Morph., Vol. 26, No. 4, pp.
625-701, figs. 1-72 in text, December 20, 1915. (See especially pp.
666-667, figs. 36, 37). See also remarks by Yonge (Univ. Calif.
Publ. Zool., Vol. 55, No. 9, p. 438, fig. 8A, 1951).

(1119) See Orcutt, C. R., West Amer. Sci., Vol. 6, Whole No. 46,
p. 98, August, 1889.

(1120) See Rogers, F. L., Jour. Entomol. Zool., Vol. 41, No. 2, p.
23, June, 1949.

(1121) See Reagan, A. B., Trans. Kansas Acad. Sci., Vol. 22, p.
211, pl. 4, fig. 40, 1909. “Quillayute formation from the old mouth
of Maxfield creek,” Pliocene.

(1122) See Dall, W. H., “Fossils of the Olympic Peninsula,”
Amer. Jour. Sci., Ser. 5, Vol. 4, p. 311, October, 1922.

(1123) Tagelus clarki Loel and Corey, Univ. Calif. Publ., Bull.
Dept. Geol. Sci., Vol. 22, No. 3, p. 229, pl. 44, figs. 2, 3, 4, Decem-
ber 31, 1932. “San Joaquin Hills, Orange County,” California.
Vaqueros Formation, early Miocene.

(1124) Cited as “Fam. 2. Solenacea” by Menke, 1830.

(1125) Cited as family Solenidae by Gray, Parry’s Second Voy-
age to the Arctic Ocean, ap., p. CCXLIV, 1824.

(1126) Dall, W. H., “Synopsis of the Solenidae of North America
and the Antilles,” Proce. U.S. Nat. Mus., Vol. 22, No. 1185, pp. 107-
112, October 9, 1899.

(1127) Habe, T., “Family Solenidae in Japan and its adjacent
areas,” Venus, Vol. 23, No. 4, pp. 188-197, pl. 18, January, 1965.
(1128) See Habe, T., Bull. Nat. Sci. Mus. (Tokyo), Vol. 7, pp. 7-
16, 1 pl., 1964.

(1129) Solen tanozawaensis Nomura, Saito Ho-On Kai Mus.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Res. Bull., No. 6, p. 64, pl. 7 (6), fig. 3, September, 1935. “'Tan-
ozawa (near the railroad station) Odose-mura.” Nisi-Tugaru dis-
trict, Aomori-ken, Northeast Honsyi, Japan, Lower Miocene.
(1130) Solen perrini Clark, Univ. Calif. Publ. Bull. Dept. Geol.,
Vol. 8, No. 22, p. 477, pl. 44, fig. 2, August 30, 1915. “Upper and
Lower San Pablo Group.”

(1131) Solen clallamensis Clark and Arnold, Univ. Calif. Publ.

Bull. Dept. Geol. Sci., Vol. 14, No. 5, p. 152, pl. 20, figs. 4 and 5,

November 6, 1923. “Sea cliffs 142 miles west of Clallam and oppo-

site fish trap, Clallam Bay, Washington.”

(1132) See Hickman, Carole J.S., Mus. Nat. Hist. Univ. Oregon,

Bull. No. 16, p. 63, pl. 8, figs. 5, 7,9, August, 1969.

(1133) See Solen cf. sicarius Gould, Kuroda, Mem. Face. Sci.

Agric. Taihoku, Imp. Univ., Vol. 22, No. 4, p. 171, 1941. Toi, Gi-

ran; Sud, Formosa.

(1134) Kuroda, T., and Habe, T., Check List and Bibliography

of the Recent Marine Mollusca of Japan, (Ed. and publ. by L.

Stach: Tokyo), p. 31, April 4, 1952.

(1135) Hirase, S., Handbook of Illustr. Shells (Revised by I.

Taki; Tokyo), pl. 49, fig. 5, 1951. Miyagi-ken, Recent.

(1136) See Hoffstetter, R., (ident. by A. Chavan), Bol. Inform.

Cienc. Nac., (Quito, Ecuador), Vol. 2, Nos. 13 and 14, p. 81, 1948.

(1137) See Holme, N. A., “The Identification of British species

of the genus Ensis Schumacher (Lamellibranchiata),” Jour.

Mar. Biol. Assoc. U.K., Vol. 29, No. 3, pp. 639-647, pl. 1, text figs.

1-5, 1951; also “The Ecology of British Species of Hnsis,” same

journal, Vol. 33, No. 1, pp. 145-172, text figs. 1-5, 1954.

(1138) See Van Urk, R. M., “The genus Hnsis in Europe,” Bas-

teria, Vol. 28, Nos. 1 and 2, pp. 13-44, pls. 1-4, 1 fig. in text, May

22, 1964; also ‘De Nederlandse Ensis-soorten,”’ Basteria, Vol. 28,

Nos. 3 and 4, pp. 60-66, pls. 1 and 2, fig. 1 (1-17), September 15,

1964.

(1139) Ensis californicus Dall, Proc. U.S. Nat. Mus., Vol. 22,

No. 1185, p. 110, October 9, 1899. “Specimen from 14 fathoms

sand, off the island of San Pedro Martir, Gulf of California.” See

also Keen, A. M., Sea Shells of Tropical West America (Stanford

Univ. Press: Stanford, California), p. 206, fig. 518, 1958. Magda-

lena Bay, Lower California, through the Gulf of California, to

Colima, Mexico.

(1140) See Hertlein, L. G., and Strong, A. M., Zoologica, Vol. 35,

Pt. 4, p. 227, 1950.

(1141) See Berry, S. S., Trans. San Diego Soc. Nat. Hist., Vol.

11, No. 15, p. 397, fig. 2, 1953.

(1142) Ensis tropicalis Hertlein and Strong, Bull. Amer. Mus.

Nat. Hist., Vol. 107, art. 2, p. 203, pl. 3, figs. 34, 35, November 28,

1955. ‘From South Passage, Pearl Islands, Panama, February

18, 1941, Station 7, dredged in 15 fathoms, sandy bottom.”

(1143) Siliqua alisoensis Packard, Univ. Calif. Publ. Bull. Dept.

Geol. Sci., Vol. 18, No. 10, p. 427, pl. 34, fig. 2, June 30, 1922.

“Chico group, Tellina ooides zone.”

(1144) See Stliqua simondsi Harris, Bull. Amer. Paleo., Vol. 6,

No. 31, p. 196, pl. 59, fig. 4, June 30, 1919. “Jackson? Eocene.”

(1145) See Siliqua sp. indet., Nagao, Sci. Repts. Tohoku Imp.

Univ., Ser. 2 (Geol.), Vol. 12, No. 1, p. 85, pl. 4, fig. 16, August 30,

1928. See also Oyama, Illustr. Handbook of Japanese Paleogene
| Molluses, (Geol. Surv. Japan), p. 204, pl. 62, fig. 5, 1960. “Range:

Eocene-Lower Oligocene.”

(1146) See Bonnot, P., Calif. Fish Game, Vol. 26, No. 3, p. 231,

1940.

(1147) Siliqua sloati Hertlein, Bull. South. Calif. Acad. Sci., Vol.
60, Pt. 1, p. 14, pl. 5, figs. 1, 2; pl. 6, figs. 4-7, issued April 30, 1961.
“from Loe. 31156 (C.A.S.) 356° 2.8 miles off Laguna Point, Men-
_ docino County, California, dredged in 46 to 49 meters (2512-27

_ fathoms).”
- (1148) See Weymouth, F. W., McMillin, H. C., and Holmes, H.
G., “Growth and age at maturity of the Pacific razor clam, Si-
liqua patula (Dixon),” Bull. U.S. Bur. Fish., Vol. 41 (1925), Fish.
| Doc. No. 984, pp. 201-236, figs. 1-27, issued July 23, 1925. Also

375

Weymouth, F. W., and McMillin, H. C., “The Relative growth
and mortality of the Pacific razor clam Siliqua patula (Dixon),
and their bearing on the commercial fishery,” Bull. U.S. Bur.
Fish., Vol. 46, 1930, Fish. Doe. No. 1099, pp. 543-567, issued Feb-
ruary 26, 1931; Weymouth, F. W., and McMillin, H. C., “Latitude
and relative growth in the razor clam, Siliqua patula,” Jour.
Exp. Biol., Vol. 8, pp. 228-249, figs. 1-10, July, 1931.

(1149) Cited as a “Division” “Mactraceae” by Bowdich, 1822;
also as “Mactraceae” by Parkinson, 1822.

(1150) Cited as “Mactradae” by Fleming, 1828; as Fam. “Mac-
tridae” by Gray, 1840.

(1151) Gray, J. E., "A synoptical catalogue of the species of cer-
tain tribes or genera of shells contained in the collection of the
British Museum and the Author’s cabinet; with descriptions of
the new species,” Mag. Nat. Hist., New Ser., Vol. 1, pp. 370-376, 6
figs., July, 1887.-Gray, Ann. Mag. Nat. Hist., Ser. 2, Vol. 11, pp.
41-43, January, 1853.

(1152) Dall, W. H., “Synopsis of the Mactridae of North Amer-
ica,” Nautilus, Vol. 8, No. 3, pp. 25-28, July, 1894.—Dall, “Sy-
nopsis of a Review of the genera of Recent and Tertiary
Mactridae and Mesodesmatidae,” Proc. Malacol. Soc. London,
Vol. 1, No. 5, pp. 203-218, March, 1895.—Dall, Trans. Wagner
Free Inst. Sci., Vol. 3, pt. 4, pp. 862-916, April, 1898.

(1153) Lamy, E. Révision des Mactridae vivants du Muséum
d'Histoire Naturelle de Paris. Jour. de Conchyl., Vol. 63, No. 3,
pp. 173-275, pl. 6, and 16 figs. in text, November 30, 1917; No. 4,
pp. 291-411, pl. 7, 43 figs. in text, February 28, 1918. See also
Tomlin, J. R. le B., “Notes on some Mactridae,” Jour. Conch.,
Vol. 17, No. 5, pp. 134-136, July, 1924.

(1154) Packard, E. L., ‘Mesozoic and Cenozoic Mactrinae of the
Pacific Coast of North America,” Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 9, No. 15, pp. 261-360, pls. 12-35, May 1, 1916.

(1155) Hertlein, L. G., and Strong, A. M., Eastern Pacific Expe-
ditions of the New York Zoological Society. XLII. Mollusks from
the West Coast of Mexico and Central America. Part IX. Zoolog-
ica, Vol. 35, Pt. 4, Family Mactridae, pp. 229-236, pl. 2, December
30, 1950.

(1156) See Keen, A. M., Sea Shells of Tropical West America
(Stanford Univ. Press: Stanford, California), pp. 154-162, 1958.
(1157) See Olsson, A. A., Mollusks of the Tropical Eastern Paci-
fic (Paleo. Res. Inst.: Ithaca, New York), pp. 320-336, 1961.
(1158) Adapted in part from Keen, 1963.

(1159) Not represented in the present collection.

(1160) See discussion by T. A. Burch, in Burch, J. Q., Min.
Conch. Club South. Calif., No. 44, pp. 8-16, February, 1945; No.
49, pp. 50-51, June, 1945.

(1161) Spisula albaria Con. var. coosensis Howe, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 14, No. 3, p. 99, pl. 9, figs. 6, 7,
September 8, 1922. The type is from the “Empire formation,
Coos Bay, Oregon.” Pliocene. This form was illustrated by Dall,
U.S.G.S., Prof. Paper 59, pl. 10, fig. 1, 1909.

(1162) Howe stated that the angulation extends to the “ante-
rior” ventral margin but Conrad’s illustration shows a distinct
posterior umbonal angulation.

(1163) See Weaver, C. E., Univ. Washington Publ. Geol., Vol. 5,
Part 1, p. 239, December, 1942 (issued December 31, 1943). See
discussion by Ellen J. Moore, U.S.G.S., Prof. Paper 419, p. 83,
1963.

(1164) See Dall, W. H., Proc. Malacol. Soe. London, Vol. 1, No. 5,
p. 211, March, 1895.

(1165) See Dall, W. H., U.S. Nat. Mus., Bull. 112, p. 52, 1921.
(1166) Hemimactra Swainson, Treatise on Malacol., p. 369, 1840.
Species cited, “H. gigantea Lam. v. 472, No. 1, grandis Sw. Sp.
Nov.”’ Type designated by Gray (Proc. Zool. Soc. London for
1847, p. 185): “M. gigantea.” This is believed to be identical with
Mactra solidissima Chemnitz, 1788, the hinge of which was well
illustrated by Lamy (Jour. de Conchyl., Vol. 63, No. 4, p. 292,
1918).

376

(1167) See Woodring, W. P., in Woodring, W. P., and Bramlette,
M.N., U.S.G.S., Prof. Paper 222, p. 88, 1950.

(1168) Spisula catilliformis Conrad, var. alcatrazensis Arnold,
Smithsonian Miscell. Col. (Quart. Issue), Vol. 50, Pt. 4, No. 1781,
p. 437 (separate p. 19), pl. 56, fig. 6, December 13, 1907. “Alcatraz
asphalt mine, near Sisquoc, Santa Barbara County, California;
locality No. 4471.” “Fernando formation, lower Pliocene por-
tion.”

(1169) Addicott cited records of Spisula falcata from the Te-
hana Member, lower portion of the Purisima Formation in Por-
tola Valley in San Mateo County, California (Proce. Calif. Acad.
Sci., Ser. 4, Vol. 37, No. 3, p. 83, 1969).

(1170) Spisula falcata brioniana Trask, Univ. Calif. Publ. Bull.
Dept. Geol. Sei., Vol. 18, No. 5, p. 152, pl. 4, figs. 2a, 2b, May 10,
1922. ‘'U.C. loe. no. 3522,” 283 mm. east and 210 mm. south of the
northwest corner of the Concord quadrangle topographic sheet,
California. According to Keen and Bentson (Geol. Soc. Amer.,
Spec. Papers 56, p. 109, 1944) this locality is “N % 1, T1S, R. 2
W,” Contra Costa Co., California.

(1171) Spissula dolabriformis Conrad, Amer. Jour. Conch., Vol.
3, Pt. 2, p. 193, September 5, 1867. “Inhabits Panama.” (Cited un-
der “Spisula” in Vol. 3, Pt. 3, Ap., p. 44, 1868).—Conrad, Amer.
Jour. Conch., Vol. 5, Pt. 2, p. 108, pl. 12, fig. 1, 1869. [Smaller fig-
ure only.]—T. A. Burch, Min. Conch. Club South. California, No.
49, p. 50, pl. 3, figs. 32 and 33 (type), 40, June, 1945 (as Spisula do-
labriformis).—Olsson, Mollusks of the tropical eastern Pacific
(Paleo. Res. Inst.: Ithaca, New York), p. 325, pl. 57, figs. 1, 1a; pl.
58, figs. 4, 4a, 1961 (as Mactra (Mactromeris) dolabriformis).
(1172) The reported occurrence of this species at Corinto, Nica-
ragua, by Eyerdam was based upon one specimen (see Pacific
Northwest Shell News, Vol. 2, No. 4, p. 55, July, 1962).

(1173) Record from this locality was based upon a right valve 42
mm. long (ventral portion imperfect), from the Mackenzie’ Gor-
don collection now in the California Academy of Sciences.

(1174) Spisula cameronis Dall, West Amer. Sci., Vol. 19, No. 3,
p. 22, June 15, 1921. ‘Pliocene (or early Pleistocene) of San Quen-
tin Bay, Lower California.”—Dall, Proc. U.S. Nat. Mus., Vol. 66,
Art. 17, No. 2554, p. 26, pl. 10, fig. 2; pl. 11, fig. 4, 1925. “Pliocene
(?) of San Quentin Bay, Lower California.”

(1175) Spisula (Hemimactra) mossbeachensis Glen, Univ. Calif.
Publ. Geol. Sci., Vol. 36, No. 2, p. 175, pl. 15, fig. 8; pl. 16, fig. 1,
November 23, 1959. ‘Merced’ formation of Pillar Point,” Plio-
cene,

(1176) Spisula longa Dall, West Amer. Sci., Vol. 19, No. 3, p. 22,
June 15, 1921. “Pliocene (or early Pleistocene) of San Quentin
Bay, Lower California.”—Dall, Proc. U.S. Nat Mus., Vol. 66, Art.
17, No. 2554, p. 27, pl. 10, fig. 1; pl. 11, fig. 3, 1925. ‘“Pliocene (?) of
San Quentin Bay, Lower California.”

(1177) Spisula (Mactromeris) hemphilli var. orcutti Manger,
Johns Hopkins Univ. Studies in Geol., No. 11, p. 301, pl. 21, Figs.
5, 6, 1934. “San Quentin Bay,” Lower California, Pleistocene.
(1178) For references to this species see footnote 1171.

(1179) Spisula strongi T. A. Burch, Min. Conch. Club South.
Calif., No. 49, p. 50, pl. 3, figs. 35-39, June, 1945. ‘Newport Bay,
Calif.” Recent.

(1180) See Woodring, W. P., in Woodring, W. P., and Bramlette,
M.N., U.S.G.S., Prof. Paper 222, p. 88, 1950.

(1181) Spisula sisquocensis Arnold, Smithsonian Misc. Coll.
(Quarterly Issue), Vol. 50, Pt. 4, No. 1781, p. 487 (separate p. 19),
pl. 56, fig. 1, December 13, 1907. “Alcatraz asphalt mine, near
Sisquoc, Santa Barbara County, California; locality No. 4471.
“Fernando formation, lower Pliocene portion.”

(1182) Mactrotoma revellei Durham, Geol. Soc. Amer., Mem. 438,
Pt. 2, p. 93, pl. 25, figs. 1, 5, August 10, 1950. “Loc. A 3548 and Re-
cent, Gulf of California.” (Loe. A 3548 = Pleistocene of Coro-
nado Island, Gulf of California. Porites reef bed overlying algal
sandstone.)

(1183) See Burch, T., Min. Conch. Club South. Calif., No. 44, pp.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

8, 17, 18, 21-22, February, 1945.

(1184) Hertlein, L. G., and Strong, A. M., Eastern Pacific Expe-
ditions of the New Zoological Society. XLII. Mollusks from the
West Coast of Mexico and Central America. Part IX., Zoologica,
Vol. 35, Pt. 4, p. 230, 1950.

(1185) Spisula strongi T. Burch, Min. Conch. Club South. Cali-
fornia, No. 49, p. 50, pl. 3, figs. 35-39, June, 1945. “The type speci-
men was collected from Newport Bay, Calif. by Mr. A. M.
Strong.”

(1186) See Mag. Nat. Hist. and Jour. Zool. Bot. Min. Geol. Me-
teor., Vol. 1, pp. 370-376, 1837.

(1187) The writers are grateful to Mr. W. I. Follett, Depart-
ment of Ichthyology, California Academy of Sciences and to the
late Harriet Exline (Mrs. Don L. Frizzell), Rolla, Missouri, for
advice concerning the problem of Schizothaerus versus Tresus.
(1188) See Min. Conch. Club South. Calif., No. 190, p. 22, July-
August, 1959.

(1189) Venus pajaroana Conrad, U.S. Pac. Railroad Expl., Vol.
7, Pt. 2, p. 192, pl. 4, figs. 1 and 2, 1857. ‘Pajaro River, Santa
Cruz.” See also Grant and Gale, Mem. San Diego Soe. Nat. Hist.,
Vol. 1, p. 405, pl. 22, figs. 6a, 6b, 8 (holotype), 1931. See also re-
marks by Woodring, in Woodring, W. P., and Bramlette, M. N.,
U.S.G.S., Prof. Paper 222, p. 89, 1950.

(1190) Lutraria maxima Middendorff, Mém. Acad. Imp. Sci.
St.-Petersbourg, Ser. 6, Vol. 6, p. 582 (Beitrage zu einer Malaco-
zoologia Rossiea, III, p. 66), pl. 19, figs. 1-4, August, 1849. “Fun-
dort: Die Insel Sitcha (Wosness.).”

(1191) Lutraria maxima Jonas, Zeitschr. f. Malakozool., Jahrg.
1, p. 34, March, 1844. ‘‘Patriam ignoro.”

(1192) Lutraria capax Gould, Proc. Boston Soc. Nat. Hist., Vol.
3, p. 217, May, 1850. “Hab. Puget Sound.”—Gould, U.S. Explor.
Exped. (Wilkes), Vol. 12, Moll., p. 395, 1852, Atlas, p. 18, pl. 34,
figs. 508, 508a, 508b, 1856.

(1193) Lutraria inflata Dunker, Zeitschr. f. Malakozool., Jahr.
10, Nr. 7, p. 112, August, 1853. “Patria California teste ornat.
Bernardi Parisiensi, qui testam misit.”

(1194) Swan, E. F., and Finucane, J. H., “Observations on the
genus Schizothaerus,” Nautilus, Vol. 66, No. 1, pp. 19-26, pls. 2, 3,
4, 1952.

(1195) Pearce, J. B., “On the distribution of Tresus nuttalli and
Tresus capax (Pelecypoda: Mactridae) in the waters of Puget
Sound and the San Juan Archipelago,” Veliger, Vol. 7, No. 3, pp.
166-170, pl. 27, and fig. 1 in text, 1965.

(1196) See Pohlo, R. H., “Ontogenetic changes of form and
mode of life in Tresus nuttalli (Bivalvia: Mactridae),” Malaco-
logia, Vol. 1, No. 3, pp. 321-330, figs. 1-6 in text, June, 1964.

(1197) Schizothaerus nuttallii bighopensis Henderson, Nau-
tilus, Vol. 45, No. 1, p. 38, July, 1931.

(1198) Schizothaerus keenae Kuroda and Habe, Illustr. Cat.
Jap. Shells, No. 4, p. 30, May 10, 1950. “For Schizothaerus nut-
talli (not Conrad), Tresus, Yokoyama, Jour. Coll. Sei. Imp. Univ.
Tokyo, 44 (1): pl. 8, fig. 8. 1922 and Illust. Eneyclop. Fauna Japan,
Rev. Edit., p. 1216, text fig. 3455. 1947."”—Hirase, Handbook II-
lustr. Shells (Bunkyokaku: Tokyo). Revised and enlarged by I.
Taki, pl. 51, fig. 6, 1951.-Swan and Finucane, Nautilus, Vol. 66,
No. 1, p. 21, pl. 2, top row of figures, 1952.—-Yamamoto and Habe,
Bull. Mar. Biol. Inst. Asamushi, Tohoku Univ., Vol. 9, No. 3, p.
110, pl. 11, figs. 12, 18, 1959. Mutsu Bay, Japan. Also other local-
ities.

(1199) See Cahn, A. R., “Clam Culture in Japan,” General
Headquarters Supreme Commander for the Allied Power Nat.
Res. Sec. (Tokyo), Rept. 146, pp. 1-103, figs. 1-38, 1941. (Schizo-
thaerus keenae, p. 84).

(1200) Schizothaerus nuttalli kissyuensis Hatai, Bull.
Biogeogr. Soc. Japan, Vol. 11, No. 13, p. 109, pl. 3, fig. 9, June,
1941. “Type locality: Kinseido, Eihoku-men, KissyQ-gun, Kan-
ky6-hoku-d6, North Tyésen.” “(Banko beds.)”’ Miocene.

(1201) Cited as Myacea by Goldfuss, 1820. Also as ‘“Myariae” by

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Bowdich, 1822, and by Parkinson, 1822.

(1202) Cited as “Family I]._Myadae?” by Leach, 1819; as
“Myadeae” by Gray, 1824; as ‘““Myadae” by Fleming, 1828; as
“Myidae” by Gray, 1828; as “Myacidae” by d’Orbigny, 1846.
(1203) Lamy, E., “Révision des Myidae vivants du Muséum Na-
tional d’Histoire Naturelle de Paris,” Jour. de Conchyl., Vol. 70,
No. 3, pp. 151-185, figs. 1-8 in text, February 25, 1927.

(1204) Antiguamya Effinger, Jour. Paleo., Vol. 12, No. 4, p. 373,
July, 1938. “Genotype, Mya (Antiguamya) arnoldi (Dickerson).””
Illustrated by Effinger, pl. 46, figs. 3, 4, 7.

(1205) Fujie, T., “On the Myarian Pelecypods of Japan. Part 1.
Summary of the Study of the Genus Mya from Hokkaido,” Jour.
Fac. Sci. Hokkaido Univ., Ser. IV. Geol. Min., Vol. 9, No. 4, pp.
381-413, pls. 1-8, figs. 1-4 in text, December, 1927; Pt. 2, Vol. 11,
No. 3, pp. 399-430, figs. 1-10 in text, March, 1962.

(1206) See MacNeil, F. S., “Evolution and distribution of the
genus Mya, and Tertiary migrations of Mollusca,” U.S.G.S.,
Prof. Paper 483-G, pp. G1-G51, pls. 1-11, figs. 1-3 in text, 1965.
(1207) See Lamy, E., Jour. de Conchyl., Vol. 70, No. 3, pp. 168-
175, 1927.

(1208) Beets, C., ‘“Précis des espéces fossiles du genre Cryp-
tomya Conrad,” Basteria, Vol. 14, Nos. 1 and 2, pp. 16-20, fig. 1,
May 1, 1950.

(1209) Venatomya Iredale, Rec. Australian Mus., Vol. 17, Pt. 9,
pp. 403, 407, June 27, 1930. The type species, Sphaenia elliptica
A. Adams, was illustrated by Hedley, Proc. Linn. Soc. New
South Wales, Vol. 38, p. 275, pl. 17, figs. 40-44, 1913.

(1210) See Burch, J. Q., Min. Conch. Club South. California, No.
44, p. 26, February, 1945.

(1211) Mya (Cryptomya) incognita Clark, Univ. Calif. Publ.
Bull. Dept. Geol., Vol. 11, No. 2, p. 160, pl. 11, fig. 8; pl. 14, fig. 4,
July 16, 1918. From U.C. Loc. 1181 = “% mile SW of town 'of
Walnut Creek; in creek bed about 100 yards to the E of Oakland
and Antioch bridge; elevation 150 feet; Contra Costa Co., long.
122°4'8”, lat. 37°53'7”.”

(1212) Cryptomya quadrata Arnold, U.S.G.S., Bull. 396, p. 71, pl.
21, figs. 2, 2a, 1909 (issued January 15, 1910). “on South side of
White Creek, about 6 miles above junction with Los Gatos Creek,
Coalinga district,” California. “Etchegoin formation, upper Mio-
cene.” [ Pliocene. |

(1213) Cryptomya oregonensis Dall, U.S.G.S., Prof. Paper 59, p.
132, pl. 11, fig. 4, April 2, 1909. ‘Miocene of Coos Bay, Oregon.”
[Pliocene. ]

(1214) See Cryptomya oregonensis Dall, Weaver, Univ. Wash-
ington Publ. Geol., Vol. 5, Pt. 1, p. 252, pl. 59, fig. 4, 1942 (issued
December 31, 1948). ‘Type locality. Fossil Point, Coos Bay, Ore-
gon.” Geol. range, “Empire formation, upper Miocene and lower
Pliocene.”

(1215) See MacGinitie, G. C., Amer. Midland Nat., Vol. 16, p.
730, September, 1935.

(1216) See Habe, T., Publ. Akkeshi Mar. Biol. Sta., No. 4, p. 23,
pl. 3, figs. 2, 4, 1955.

(1217) Smith, E. A., “Observations on the genus Sphenia, with
descriptions of new species,” Ann. Mag. Nat. Hist., Ser. 6, Vol.
12, No. 70, pp. 277-281, pl. 15A, October, 1893.

(1218) Sphenia pacificensis de Folin, Les Méléagrinicoles
(Havre), p. 15, pl. 2, figs. 10, 11, 1867. According to Lamy (Jour.
de Conchyl., Vol. 70, No. 3, p. 181), this species was “trouvé a
Panama sur des Huttres perliéres.”

(1219) See Keen, A. M., Sea Shells of Tropical West America
(Stanford Univ. Press: Stanford, California), p. 207, No. 52la,

, 1958.

(1220) Sphenia trunculus Dall, Proce. U.S. Nat. Mus., Vol. 52,
No. 2183, p. 415, December 27, 1916. “San Diego, California,
among barnacles on the wharf piles.”

(1221) Cited as “Division XII. Corbulaceae” by Bowdich, Elem.

_ Conch., Pt. 2, pp. 3, 18, 1822; as Corbuleae by Parkinson, 1822; as

Corbulea by Gould, 1833; as “Familia 6, Corbulacea Lamk.” by

377

Philippi, 1836; as Corbulacea by Sowerby, 1839.

(1222) Cited as Family “Corbuladae” by Fleming, 1828.

(1223) Gardner, J., “The Nomenclature of the Superspecific
Groups of Corbula in the lower Miocene of Florida,” Nautilus,
Vol. 40, No. 2, pp. 41-47, October, 1926.

(1224) Vokes, H. E., “Supraspecifie Groups of the Pelecypod
Family Corbulidae,” Bull. Amer. Mus. Nat. Hist., Vol. 86, Art. 1,
pp. 5-32, pls. 1-4, October, 1945.

(1225) Lamy, E., “Révision des Corbulidae vivants du Muséum
National d’Histoire Naturelle de Paris,” Jour. de Conchyl., Vol.
84, No. 1, pp. 5-33, 6 figs. in text, July 31, 1941; Vol. 84, No. 2, pp.
121-144, November 15, 1941; Vol. 84, No. 3, pp. 211-254, December
2, 1941. See also Lamy, E., “Notes sur les espéces rangées par
Lamarck dans le genre Corbula Bruguiére,” Bull. Mus. Nat.
d’Hist. Nat., Paris, Vol. 32, No. 1, pp. 81-85, 1926.

(1226) See Bull. Zool. Nomen., Vol. 4, Pts. 10-12, p. 225 (con-
cerning Article 25), June, 1950.

(1227) See Eames, F. E., Philos. Trans. Roy. Soc. London, Ser.
B., Biol. Sci., No. 627, Vol. 235, p. 435, 1951.

(1228) See Gray, J. E., Proc. Zool. Soc. London for 1847, p. 191.
Type indicated as "Corb. sulcata.”

(1229) Notocorbula Iredale, Rec. Australian Mus., Vol. 17, Pt. 9,
pp. 404, 407, June 27, 1930. “Type Notocorbula vicaria Iredale,”
p. 404, pl. 64, figs. 8, 9; pl. 65, figs. 3, 4, 9. “Sydney Harbour.”
“New South Wales.”—Vokes, Bull. Amer. Mus. Nat. Hist., Vol.
86, Art 1, p. 13, pl. 1, figs. 6-10 (reproductions of Iredale’s figures
of Notocorbula vicaria), 1945. See also discussion by Stenzel,
Krause, and Twining, Univ. Texas, Bull. Bur. Econ. Geol., No.
5704, pp. 168-170, 1957.

(1230) See Woodring, W. P., U.S.G.S., Prof. Paper 190, p. 56,
1938.

(1231) Yonge, C. M., “On the Habits and Adaptations of Aloidis
(Corbula) gibba,” Jour. Mar. Biol. Assoc. U.K., Vol. 26, No. 3, pp.
358-376, 14 figs. in text, July, 1946.

(1232) McLean, R. A., “The Sculpture of Inaequivalve Mol-
lusks,”’ Nautilus, Vol. 55, No. 4, pp. 142-1438, 1942.

(1233) See Stewart, R. B., in Woodring, W. P., Stewart, R. B.,
and Richards, R. W., U.S.G.S., Prof. Paper 195, opp. p. 78, and p.
95, 1940 (1941).

(1234) Corbula speciosa Reeve, Conch. Icon., Vol. 2, Corbula, sp.
6, pl. 1, fig. 6, August, 1843. “Hab. Gulf of Nicoya (dredged in
seven fathoms water).”” A new name for Corbula radiata Sow-
erby, 1833, not Corbula radiata Brocchi, 1814.—Olsson, Mollusks
of the Tropical eastern Pacific (Paleo. Res. Inst.: Ithaca, New
York), p. 438, pl. 77, figs. 7, 7a, 7b, 7c, 1961 (as Varicorbula speci-
osa). Gulf of California to the Gulf of Nicoya, Costa Rica.

(1235) Corbula nuciformis Sowerby, Proc. Zool. Soc. London,
for 1833, p. 35, issued May 17, 1833. “Hab. in America Centrali.”
“Found at a depth of six fathoms in a sandy mud at Real
Llejos.”—Hertlein and Strong, Zoologica, Vol. 35, Pt. 4, p. 241, pl.
2, fig. 1, 1950 (as Aloidis (Caryocorbula) nuciformis).

(1236) Corbula (Varicorbula) granti Olsson, Bull. Amer. Paleo.,
Vol. 27, No. 106, p. 197 (45), pl. 15 (2), figs. 8, 9, December 25,
1942. “Quebrada Pefitas,”’ Costa Rica, and “Charco Azul,” Pan-
ama, Pliocene.

(1237) Corbula (Varicorbula) ef. bradleyi Nelson, Olsson, Bull.
Amer. Paleo., Vol. 27 (106), p. 197 (45), 1942. “Quebrada Mellisa,”
Panama, Pliocene.

(1238) Corbula biradiata Sowerby, Proc. Zool. Soc. London for
1838, p. 35, issued May 17, 1883. ‘Hab. ad Chiriqui et ad sinum
caraccensem.” “Found in mud and sand in from three to six
fathoms at Chiriqui, and in seven fathoms in the Bay of Ca-
raccas.’’"—Reeve, Conch. Icon., Vol. 2, Corbula, species 3, pl. 1, fig.
3, 1843.—Hertlein and Strong, Zoologica, Vol. 35, Pt. 4, p. 238,
1950 [as Corbula (Caryocorbula) biradiata).

(1239) Cited as Family “Hyatellidae” by Gray, Parry’s second
Arctic Voyage, ap., p. CCXLIV, 1824; and as Saxicavidae by
Gray, 1840.

378

(1240) See Kiihnelt, W., ‘““Bohrmuschelstudien II,’’ Palaeobiol.,
Bd. 5, Lief. 3, pp. 371-408, pls. 21-23, figs. 1-10 in text, 1933.
[Saxicavidae, pp. 384-385].

(1241) See White, K. M., Proc. Malacol. Soc. London, Vol. 25,
pt. 2, p. 79, figs. 37, 38, 1942.

(1242) See Tryon, G. W., Jr., “Catalogue of the Families Saxica-
vidae, Myidae and Corbulidae,” Amer. Jour. Conch., Vol. 4, Pt. 5,
Ap. pp. 59-68, May 6, 1869. [Saxicavidae, pp. 59-61.]

(1243) Lamy, E., “Révision des Saxicavidae vivants du Muséum
Nationale d'Histoire Naturelle de Paris,” Jour. de Conchyl., Vol.
68, No. 3, pp. 218-248, October, 1924; Vol. 68, No. 4, pp. 261-283,
March, 1925.

(1244) See Saxicava? albertensis Landes, Dept. Mines Res. Can-
ada, Geol. Surv., Mem. 221, p. 163, pl. 6, fig. 3, 1940. ‘“Pakowki
formation, Bear Gulch sandstone in Bear Gulch, L.S. 2, sec. 18,
tp. 2, range 9, W. 4th mer.”

(1245) Pseudosaxicava Chavan, Schweiz. Palaeo. Abhandl., Vol.
69, No. 3, p. 119, 1952. Type (by monotypy): Pseudosaxicava ber-
nardi Chavan, p. 119, pl. 4, figs. 69-71, 1952. Cordebugle, Cal-
vados, France, late Jurassic.

(1246) See Hiatella sakhalinensis Takeda, Oyama, Mizuno, and
Sakamoto, “Illustrated Handbook of Japanese Paleogene Mol-
lusks,” Geol. Surv. Japan, p. 207, pl. 63, figs. la-d, 1960.

(1247) See Dell, R. K., Discovery Repts., Vol. 33, pp. 222-226,
1964.

(1248) Mytilus pholadis Linnaeus, Mantissa, 2, p. 548, 1771.
“Habitat in Oceano septentrionalis.”—Chemnitz, Neues Syst.
Conehyl.-Cab., Bd. 8, p. 154, pl. 82, figs. 735, 785b, 1785.—I. S. Old-
royd, Stanford Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 209, pl.
51, fig. 5, 1924 (as Saxicava pholadis). See also illustrations by
Sowerby in Reeve, 1878, and by Sars, 1878.

(1249) See Richards, H. G., Bull. Geol. Soc. Amer., Vol. 51, No.
11, p. 1785, 1940. f
(1250) See Elton, C. S., and Baden-Powell, D. F. W., Geol. Mag.,
Vol. 68, No. 807, p. 401, 1931.

(1251) Saxicava antarctica Philippi, Archiv f. Naturgesch.,
Jahrg. 11, Bd. 1. p. 51, 1845. “Patria: insulae Chonos infra
Chiloe.”’ .
(1252) See Dall, W. H., Bull. Mus. Comp. Zodl., Vol. 48, No. 6, p.
424, 1908.

(1253) See Olsson, A. A., Mollusks of the Tropical Eastern Paci-
fic (Paleo. Res. Inst.: Ithaca, New York), p. 425, pl. 77, figs. 6, 6a,
1961.

(1254) Saxicava solida Sowerby, Proc. Zool. Soc. London for
1834, p. 88, October 25, 1834. “Hab. ad Sanctam Elenam.”
“Found in clefts of rock brought up from a depth of eighteen
fathoms.”—Sowerby, in Reeve’s Conch. Icon., Vol. 20, Saxicava,
sp. 6, pl. 1, fig. 6, 1875. ““Hab.—?”” —Sowerby, Thes. Conch., Vol. 5,
p. 138, pl. 471, fig. 12, 1884. “Hab.—?”

(1255) Dell, R. K., Discovery Repts., Vol. 33, p. 224, 1964.

(1256) See von Koenen, A., Palaeontographica, Bd. 16, p. 120,
1867.

(1257) See Saxicava arctica Linné, Gorges, Abhandl. Hessis-
chen Landesamt Bodenforsch., Heft. 4, p. 54, 1954. Kassel, Ger-
many, upper Oligocene.

(1258) See Saxicava arctica Linné, Cossmann and Peyrot, Act.
Soe. Linn. Bordeaux, Tom 638, (Conch. Néogéne de 1|’Aquitaine,
Tome 1), pp. 131-133, pl. 3, figs. 20-27, 1909.

(1259) See Saricava arctica bilineata Conrad, Richards and
Harbison, Proc. Acad. Nat. Sci. Philadelphia, Vol. 94, p. 201, pl.
16, figs. 18, 14, 1942. New Jersey, Miocene.

(1260) See Saxicava orientalis Yokoyama, Jour. Coll. Sci. Im-
per. Univ. Tokyo, Vol. 39, Art. 6, p. 106, pl. 7, figs. 2, 3, March 22,
1920. Upper Musashino of Kazusa, Japan.-Yamamoto and
Habe, Bull. Mar. Biol. Sta. Asamushi, Tokyo Univ., Vol. 9, No. 3,
p. 111, pl. 12, figs. 16, 17, 1959. Mutsu Bay, Japan, Recent.

(1261) See Soper, E. K., and Grant, U. S., “Geology and Pa-
leontology of a portion of Los Angeles, California,” Bull. Geol.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Soc. Amer., Vol. 43, No. 4, p. 1060, 1932.

(1262) See Dall, W. H., Seventeenth Ann. Rept. U.S.G.S., Pt. 1,
p. 845, 1895 (1896).

(1263) See MacNeil, F. S., “Cenozoic Megafossils of Northern
Alaska,” U.S.G.S., Prof. Paper 294-C, p. 119, 1957.

(1264) See Dall, W. H., in Mertie, J. B., Jr., U.S.G.S., Bull. 836-B,
p. 129, 1931.

(1265) See Hatai, K., and Nisiyama, S., Sci. Repts. Tohoku
Univ., Sendai, Japan, Second Ser. (Geol.), Spec. Vol. No. 3, p. 68,
1952.

(1266) Hunter, W. R., “The Structure and behavior of Hiatella
gallicana (Lamarck) and H. arctica (L.) with special reference
to the boring habits,” Proc. Roy. Soe. Edinburgh, Vol. 63, Sec. B,
No. 3, pp. 271-289, figs. 1-12 in text, 1949.

(1267) Ockelmann, W. K., Medd. om Grénland, Bd. 122, No. 4,
pp. 1385-142, 1958. See also Sorgenfrei, T., “Molluscan assem-
blages from the marine middle Miocene of South Jutland and
their environments,” Vol. 1. Reprint from Geol. Surv. Denmark.
IL., Ser. 79, pp. 125-128, pl. 20, fig. 66 (a-e), 1958. Oligocene to re-
cent.

(1268) Cox, L. R., Proce. Malacol. Soe. London, Vol. 27, Pt. 1, pp.
30-31, 1946.

(1269) Lamy, E., Jour. de Conchyl., Vol. 68, No. 4, pp. 266-279,
1925.

(1270) See Vokes, H. E., Jour. Paleo., Vol. 30, No. 3, pp. 766-767,
May, 1956.

(1271) See Dechaseaux, C., in Traité de Paléontologie publié
sous la direction de Jean Piveteau (Masson et Cie, éditeurs:
Paris), Tome 2, p. 311 (Panopeidae, p. 322), 1952.

(1272) Panopea (var.) solida Dall, Trans. Wagner Free Inst.
Sci., Vol. 3, Pt. 4, p. 831, April, 1898. “San Francisco, California.”
(1273) Packard, E. L., Univ. Calif. Publ. Zool., Vol. 14, No. 2, p.
287, 1918.

(1274) Panope generosa solida Dall, I. S. Oldroyd, Stanford
Univ. Publ. Univ. Ser. Geol. Sci., Vol. 1, p. 206, pl. 3, fig. 11, 1924.
(1275). Keen, A. M., Min. Conch. Club South. Calif., No. 44, p. 30,
February, 1945.

(1276) Panopea (var.) globosa Dall, Trans. Wagner Free Inst.
Sei., Vol. 3, Pt. 4, p. 881, April, 1898. “Head of the Gulf of Califor-
nia; Palmer.’’—Dall, Proce. U.S. Nat. Mus., Vol. 24, No. 1264, p.
560, pl. 40, fig. 1, March 31, 1902 (as Panopea globosa).—Keen, A. M.,
Sea Shells of Tropical West America (Stanford Univ. Press:
Stanford, California), p. 213, fig. 545, 1958. “Head of the Gulf of
California to off San Marcos Island, in 33 fathoms depth.”
(1277) Mya abrupta Conrad, U.S. Explor. Exped. (Wilkes), Vol.
10, Geol., p. 723, Geol. Atlas, pl. 17, figs. 5, 5a, 1849. “Astoria, Ore-
gon.

(1278) See Moore, Ellen J., U.S.G.S., Prof. Paper 419, p. 83, pl.
30, figs. 3-4; pl. 31, figs. 4 and 7 (type), 1968 (as Panope (Panope)
abrupta).

(1279) Glycimeris estrellanus Conrad, U.S. Pac. Railroad Expl.,
Vol. 7, p. 194, pl. 7, fig. 5, 1857. “Locality.—Panza and Estrella
Valleys.” California.

(1280) Clark, B. L., Univ. Calif. Publ. Bull. Dept. Geol., Vol. 11,
No. 2, p. 161, 1918.

(1281) Panope ramonensis Clark, Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 15, No. 4, p. 106, pl. 10, figs. 2, 3, January 5, 1925.
“U.C. loe. 1131, 4 mile southwest of town of Walnut Creek, on
east side of Oakland Antioch Railway bridge, elevation 150 feet,
Contra Costa County, California.”

(1282) Panopaea japonica A. Adams, Proe. Zool. Soe. London
for 1849, p. 170, pl. 6, fig. 5 (issued January to June, 1850). “Hab.
Japoniam.” See also Nomura, Saito Ho-On Kai Mus., Res. Bull.
No. 5, p. 94, 1935.

(1283) See McLean, R. A., Nautilus, Vol. 49, No. 1, p. 34, 1935.
(1284) Kanno, S. “Fossil and Recent Species of the Genus Pan-
omya from Japan,” Trans. Proc. Palaeont. Soc. Japan, New Ser.,
No. 25, pp. 11-16, pl. 2, April 30, 1957.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

(1285) Glycimeris arctica Lamarck, Hist. Nat. Anim. s. Vert.,
Vol. 5, p. 458, July, 1818. “Habite l’Océan arctique, la Mer
blanche.”
(1286) Panomya ampla Dall, Trans. Wagner Free Inst. Sci., Vol.
3, Pt. 4, p. 833, April, 1898. “Pleistocene of the North Pacific, Ber-
ing, and Okhotsk Seas, and recent in the same region.”’—Dall,
Proc. U.S. Nat. Mus., Vol. 24, No. 1264, p. 560, pl. 40, figs. 3, 4,
March 31, 1902. According to Keen, “The type locality of Pan-
omya ampla is Kyska Harbor, according to the holotype label.”
See J. Q. Burch, Min. Conch. Club South. Calif., No. 44, p. 31,
February, 1945.
(1287) Middendorff, A. T. von, “Beitrage zu einer Malacozoo-
logia Rossica,” Pt. 3, Mém. Sci. Nat. Acad. Imper. Sci., St.
Pétersbourg, Ser. 6, Vol. 6 [but Vol. 8 of Sci. Math., Phys. et
Nat.], and as a volume with separate pagination, Pt. 3, p. 77, pl.
20, fig. 11, 1849. ‘““Fundort: Das Eismeer an den Kiisten des Rus-
sischen Lapplandes (Baer, Midd.); das Weisse Meer (Lamarck);
das Ochotskische Meer (Midd.).”
(1288) MacNeil, F. S., Jour. Paleo., Vol. 17, No. 1, p. 93, pl. 16,
figs. 7, 10, January, 1943.
(1289) Oldroyd, I. S., Stanford Univ. Publ. Univ. Ser. Geol. Sci.,
Vol. 1, p. 207, pl. 10, fig. 3, 1924.
(1290) Grant, U. S., IV, and Gale, H. R., Mem. San Diego Soc.
Nat. Hist., Vol. 1, p. 426, pl. 21, figs. 10a, 10b, 1931.
(1291) Kira, T., Mon. Japanese Shells, p. 128, pl. 61, fig. 17, 1954.
(1292) Panomya (ampla var.?) chrysis Dall, U.S.G.S., Prof. Pa-
per 59, p. 183, pl. 11, fig. 7, 1909. “Miocene beds of Goldwashers
Gulley, Coos Bay, Oregon.”[ Pliocene. |
(1293) Howe, H. V., Univ. Calif. Publ. Bull. Dept. Geol. Sci., Vol.
14, No. 3, p. 92, 1922.
(1294) Panomya arctica Lamarck, new variety, turgida Dall,
Proc. U.S. Nat. Mus., Vol. 52, No. 2183, p. 416, December 27, 1916.
“The type-specimen is from Popoff Strait in the Shumagin
group, Alaska.”’—Dall, U.S. Nat. Mus., Bull. 112, p. 54, pl. 2, fig. 1,
1921.
(1295) Panomya (Arctica) turgida Dall, Clark, B. L., Bull. Geol.
Soc. Amer., Vol. 43, No. 3, p. 828, pl. 17, figs. 6 and 9, 1932.
(1296) See Eyerdam, W. J., Min. Conch. Club South. Calif., No.
68, p. 16, April, 1947.
(1297) See Schlesch, H., Abhandl. Archiv f. Molluskenkunde,
Bd. 1, Heft 3, p. 16, 1924.
(1298) Panomya nipponica Nomura and Hatai, Saito Ho-on
Kai Mus., Res. Bull. No. 5, Geol. No. 2, p. 20, pl. 1, figs. 7a, 7b,
March, 1935. ‘‘Tadaide,” northeast Honsyf, Japan. “Holotype
from Tennémae” (p. 46).
(1299) Habe, T., Publ. Akkeshi Mar. Biol. Sta., No. 4, p. 21, pl. 5,
figs. 3, 4, 1955.
(1300) Panomya ef. P. beringiana Dall, Woodring, in Woodring,
W. P., and Bramlette, M. N., U.S.G.S., Prof. Paper 222, table
opp. p. 48, p. 91, 1950.
(1301) See Panomya beringiana Dall, Faustman, Univ. Calif.
Publ. Geol. Sci., Vol. 41, No. 2, p. 125, pl. 1, fig. 9, 1964.
(1302) Cited as “S. F. Pholadaria” by Rafinesque, 1814; as a
“Division” “Pholadariae” by Bowdich, 1822; as “‘Pholadea” by
Menke, 1830; as “Order Pholadacea” by Stoliezka, 1871.
_ (1303) Cited as “Family I.—Pholadidae?” by Leach (Ann.
Philos., Vol. 14, p. 203, September, 1819); as Family ‘“Pholadae”
by Fleming, 1828; as Family “Pholadidae” by d’Orbigny, 1846.
(1304) Turner, R. D., “The Family Pholadidae in the western
Atlantic and the eastern Pacific. Pt. 1.—Pholadinae,” Johnsonia,
Vol. 3, No. 33, pp. 1-63, pls. 1-34, May 17, 1954; ‘Part IJ.—Marte-
slinae, Jouannetiinae and Xylophaginae,” Vol. 3, No. 34, pp. 65-
160, pls. 35-98, March 29, 1955.
_ (1805) Lamy, E., “Révision des Pholadidae vivants du Muséum
National d’Histoire Naturelle de Paris,” Jour. de Conchyl., Vol.
69, No. 1, pp. 19-51, July 5, 1925; Vol. 69, No. 2, pp. 79-103, Octo-
| ber 10, 1925; Vol. 69, No. 3, pp. 136-168, 3 figs. in text, January 31,
1926; Vol. 69, No. 4, pp. 193-222, May 15, 1926.

379

(1306) See MacGinitie, G. E., “Ecological Aspects of a Califor-
nia Estuary,” Amer. Midland Nat., Vol. 16, No. 5, pp. 629-765,
figs. 1-21, September, 1935. (See pages 731-735, fig. 19).

(1307) See Yonge, C. M., Sea Frontiers, Vol. 10, No. 2, p. 108,
May, 1964.

(1308) Zirfaea gabbi Tryon femii Adegoke, Univ. Calif. Publ.
Geol. Sci., Vol. 80, p. 154, pl. 9, figs. 2, 8, 11, 12; pl. 10, figs. 3, 5, 6,
13, September 25, 1969.

(1309) Pholadidea Turton, A Conchological Dictionary of the
British Islands (London), p. 147, 1819. Sole species, Pholadidea
loscombiana [Turton], “on the strand near Exmouth.”—Turner,
Johnsonia, Vol. 3, No. 34, p. 89, 1955.

(1310) Martesia intercalata Carpenter, Cat. Mazatlan Shells in
Brit. Mus., p. 13, 1857. ‘“Hab.—Mazatlan; in Spondylus La-
marckii, extremely rare; Havre Col.”

(1311) See Smith, E. H., “Functional morphology of Penitella
conradi relative to shell-penetration,’ Amer. Zool., Vol. 9, No. 3,
Ed. 2, pp. 869-880, figs. 1-7, August, 1969.

(1812) Cited by Jordan, E. K., “Quaternary and Recent Mollus-
can Faunas of the west coast of Lower California,” Bull. South.
Calif. Acad. Sci., Vol. 23, Pt. 5, September-October (issued Octo-
ber 25), p. 154, 1924.

(1313) See Grant, U. S., IV, and Quayle, E. H., in Soper, E. K.,
“Geology of the Central Santa Monica Mountains, Los Angeles
County,” Calif. Jour. Mines Geol., Vol. 34, No. 2, p. 168, 1939. To-
panga Formation.

(1314) See Pholadidea aff. penita Conrad, B. L. Clark, Univ.
Calif. Publ. Bull. Dept. Geol. Sci., Vol. 11, No. 2, p. 162, 1918.
(1315) Pholadidea (Penitella) lorenzana Clark, Univ. Calif.
Publ. Bull. Dept. Geol. Sci., Vol. 15, No. 4, p. 107, pl. 18, figs. 5, 6,
January 5, 1925.

(1316) Penitella turnerae Evans and Fisher, Veliger, Vol. 8, No.
4, p. 222, pl. 31, figs. 1, P. t., 2, P. t., April 1, 1966. “Type locality:
The north end of Fossil Point in Coos Bay, Oregon, at 43°22’
North Latitude and 124°15’ West Longitude. Depth zero foot
tide level, in soft muddy sandstone.” Recent.

(1317) Pholadidea (Penitella) chishimana Habe, Akkeshi Mar.
Biol. Sta., No. 4, p. 23, pl. 7, figs. 8, 9, February, 1955. “Type local-
ity: Horomusir Island, northern Kurile Islands.”

(1318) See for example Pholadidea penita Conrad,
Slodkewitsch, Paleo. USSR., Vol. 10, Part 3, fase. 18, p. 506; Fase.
19, pl. 105, figs. 3-5; pl. 106, figs. 1, la, 1938. Kamtschatka, Ter-
tiary. Also Ilyina, A. P., Trudy Vsesoiuznogo Neftianogo
Nauchno-issledovatel’skogo Geologo-razvedochnogo Instituta
(VNIGRI) (Moskva), Vypusk 202, p. 57, pl. 18, fig. 5; pl. 25, fig. 7,
1963.

(1319) Cited as ‘Famille. Teredaria” by Rafinesque, 1815; as
“Famille Teredinites” by Latreille, Familles naturelles du régne
animal (Paris), p. 224, 1825; as Teredinidae by Fleming, 1828.
(1320) Turner, R. D., “A survey and illustrated catalogue of the
Teredinidae (Mollusca: Bivalvia),” Mus. Comp. Zool., Harvard
University, pp. 1-265; pls. 1-64, figs. 1-25 in text, 1966.

(1321) Clench, W. J., and Turner, R. D. “The genus Bankia in
the western Atlantic,” Johnsonia, Vol. 2, No. 19, pp. 1-28, pls. 1-
16, April 27, 1946. See also Bartsch, P., U.S. Nat. Mus., Bull. No.
122, pp. 1-51, 1 fig. in text, pls. 1-87, August 4, 1922.

(1322) Xylophaga Turton, Conchyl. Insul. Brittan., p. 258, 1822.
Sole species, Xylophaga dorsalis Turton [ = Teredo dorsalis
Turton, 1819.]—Turner, Johnsonia, Vol. 3, No. 34, p. 145, 1955.
(1323) Xylotomea Dall, Trans. Wagner Free Inst. Sci., Vol. 3, Pt.
4, p. 821, April 1898.

(1324) Cited as “Order Anomalodesmacea” by Dall, 1895.

(1325) Cited as Order Eudesmodontida by Cox, 1960.

(1326) Cited as subfamily “S. F. Pandoracia’” by Rafinesque,
1815.

(1327) Cited as family Pandoridae by Gray, 1840.

(1328) Boss, K. J., and Merrill, A. S., “The family Pandoridae in
the western Atlantic,” Johnsonia, Vol. 4, No. 44, pp. 181-215, pls.

380

115-126, February 12, 1965.
(1329) See Boss, K. J., “Catalogue of the family Pandoridae
(Mollusca: Bivalvia),’”” Occas. Papers Dept. Moll. Mus. Comp.
Zool., Harvard Univ., Vol. 2, No. 33, pp. 413-424, November 8,
1965.
(1330) Adapted from Olsson, 1961.
(1331) Not represented in the present collection.
(1332) See Faustman, W. F., Univ. Calif. Publ. Geol. Sci., Vol.
41, No. 2, p. 117, 1964.
(1333) Pandora (Kenerlyia) pseudobilirata Nomura and Hatai,
Saito Ho-on Kai Mus. Res. Bull., No. 19, (Geol. No. 7), p. 87, pl. 4,
figs. 15a, 15b, July, 1940. Station 11, Kyaroku-sima and its vicin-
ity, Recent.
(1334) See Pandora (Heteroclidus) hukusimana Otuka, Jour.
Geol. Soc. Japan, Vol. 50, No. 592, p. 224, pl. 2, fig. 8, January 20,
1943. Futatsugoya, Miocene.
(1335) See Dall, W. H., Trans. Wagner Free Inst. Sci., Vol. 3, Pt.
6, p. 1521, October, 1903. “Miocene of California (var. Gabbi)
near San Buenaventura, Gabb.” [?Pleistocene. ]
(1336) Cited as ‘Family Periplomidae,” by Dall, 1895.
(1337) Lamy, E. ‘“Révision des Periplomatidae vivants du Mu-
séum National d’Histoire Naturelle de Paris,” Jour. de Conchyl.,
Vol. 75, No. 4, pp. 303-321, 1931.
(1338) See Iredale, T., Rec. Australian Mus., Vol. 17, No. 9, p.
387, June 27, 1930.
(1339) Periploma sanctaecrucis Arnold, Proc. U.S. Nat. Mus.,
Vol. 34, No. 1617, p. 382, pl. 35, fig. 8, August 8, 1908. “Santa Cruz
quadrangle, Santa Clara County, locality No. 42, in soft sand-
stone on hill on the east side of Madera Creek, 2! miles south-
west of Mayfield.” “Upper Miocene.” [“Purisima,” Pliocene,
according to Keen and Bentson, 1944, p. 96.]
(1340) Periploma teevani Hertlein and Strong, Zoologica, Vol.
31, Pt. 3, No. 8, p. 95, pl. 1, figs. 2 and 6, December 5, 1946. “Lat.
15°44’N., Long. 96°05’W., Tangola-Tangola Bay, Oaxaca, Mex-
ico, dredged in 30 fathoms (55 meters), mud.”
(1841) Periploma venezuelana wiedenmayeri H. K. Hodson,
Bull. Amer. Paleo., Vol. 16, No. 59, p. 7, pl. 1, figs. 3, 5, 7, October
1, 1931. “2 kilometers south and 600 meters east of La Compana,
District of Democracia, State of Faleén. (La Compana is 11.5 ki-
lometers east and 2 kilometers south of Urumaco.)’”’ Venezuela,
lower middle Miocene.
(1342) Periploma cryphia Woodring, U.S.G.S., Prof. Paper 190,
p. 56, pl. 9, figs. 4, 6, 1938. Holotype from “Union Oil Co. Hellman
No. 17, Dominguez field, depth 3,939 feet (U.S.G.S. locality
13898)."’ Repetto Formation, early Pliocene.
(1343) Cochlodesma leana floridana Mansfield, Jour. Paleo., Vol.
11, No. 7, p. 611, pl. 85, figs. 12, 14, October, 1937. ‘Lower part of
the upper Miocene bed, Ecphora zone, at Jackson Bluff, Leon
County, Florida.”
(1344) Cochlodesma Couthouy, Boston Jour. Nat. Hist., Vol. 2, p.
170, 1839. Type (designated by Gray, Proc. Zool. Soc. London for
1847, pp. 190-191): “Mya praetenuis” [Pulteney, Catalogues of
the Birds, Shells, ... , Plants, ... Dorsetshire, ed. 1, p. 28, 1799.
“Petiver received his shell from Poole, where I have found it on
the sands, in the harbour, and on the North shore, near
Brownsea Isle, and once a few valves on the shore between
Waymouth and Portland.” Also Illustrated by Soot-Ryen,
Trémso Mus. Arsheft. (Naturhist. Avd. No. 17), Vol. 61, No. 1, p.
34, pl. 5, figs. 3, 4; pl. 7, fig. 5, pl. 10, fig. 12, 1941 (as Cochlodesma
(Bontaea) praetenue). Norway to France, Recent. |

Vokes (Jour. Paleo., Vol. 30, No. 3, p. 764, May, 1956) pointed
out that Bontaea (Leach MS) Brown, 1844, and Galaxwra Leach,
1852, are synonyms of Cochlodesma. Aperiploma Habe (Gen.
Jap. Shells, Peleeypoda, No. 3, p. 265, 1952), with the type species
Cochlodesma leana ““Conthouy” [= Anatina leana Conrad (Jour.
Acad. Nat. Sci. Philadelphia, Vol. 6, p. 263, pl. 11, fig. 11, April,
1831; also illustrated by Gould (Rept. Invert. Massachusetts,
Boston, edit. 2, by W. G. Binney, p. 68, fig. 383, 1870); see synon-

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

yms by Lamy (Jour. de Conchyl., Vol. 75, No. 4, p. 318, 1931)] was
proposed as a subgenus of Periploma.

(1345) Cited as Subfamily Thracinae by Stoliezka, 1871; also as
Family Thraciidae by Dall, 1895.

(1346) Lamy, E., Révision des Thraciidae vivants du Muséum
National d’Histoire Naturelle de Paris,” Jour. de Conchyl., Vol.
75, No. 3, pp. 213-241, September 30, 1931; Vol. 75, No. 4, pp. 285-
302, December 10, 1931.

(1347) Soot-Ryen, T., “Northern Pelecypods in the Collection of
Tromsé Museum. I. Order Anomalodesmacea Families Phola-
domyidae, Thraciidae and Periplomatidae,” Tromsé Mus. Ar-
shefter (Naturhist. Avd. Nr. 17), Vol. 61, No. 1, pp. 1-41, pls. 1-10,
fig. 1 (map in text), July 20, 1941. (Thraciidae, pp. 13-34.)

(1348) Allen, J. A., “The British Species of Thracia (Eu-
lamellibranchia),” Jour. Mar. Biol. Assoc. U.K., Vol. 41, No. 3, pp.
723-735, pl. 1, text-figs. 1-5, October, 1961.

(1349) Blainville, H. M. D. de, “Manuel de Malacologie,” p. 660,
1825.

(1350) See Keen, A. M., Min. Conch. Club South. Calif., No. 37,
p. 18, July, 1944.

(1351) See Deshayes, G. P., Dict. Class. Hist. Nat., Vol. 16, p.
235, 1830. “... Thracia pubescens. Cette coquille n’est autre que
le Mya pubescens de Linné. ... nous avons su que cette belle es-
péce était devenue le type d’un nouveau genre du Zoologiste
anglais.”

(1352) Kamada, Y., “On the Tertiary Species of Thracia from
Japan,” Sci. Repts. Fac. Arts and Lit., Nagasaki Univ., No. 4, pp.
93-107, pl. 1, March 28, 1955.

(1353) Thracia trapezoides Conrad, U.S. Explor. Exped. (Wil-
kes), Geol., Vol. 10, p. 728, Atlas, pl. 17, fig. 6a, 1849. “Astoria,
Oregon.” [Miocene]—Dall, U.S.G.S., Prof. Paper 59, p. 135, pl. 2,
fig. 14; pl. 18, fig. 7, 1909 (as Thracia trapezoidea). Astoria, Ore-
gon, Miocene.— Weaver, Univ. Washington Publ. Geol., Vol. 5, p.
117, pl. 25, fig. 7; pl. 29, fig 5; pl. 104, fig. 11 (holotype), 1942 (is-
sued December 31, 1943.)—Moore, Ellen J., U.S.G.S., Prof. Paper
419, p. 84, pl. 26, fig. 3; pl. 31, fig. 6 (holotype), 1963.

(1354) See Thracia kakumana Yokoyama, Kamada, Sci. Repts.
Fac. Arts and Lit., Nagasaki Univ., No. 4, p. 96 (4), pl. 1, fig. 11,
1955. Japan, Pliocene. See also Makiyama, Palaeo. Soc. Japan,
Spec. Paper No. 3, pl. 4, figs. la, 1b, 1957.

(1355) Cyathodonta weaveri Clark, Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 11, No. 2, p. 187, pl. 18, fig. 10; pl. 14, fig. 1, July 16,
1918. One half mile southwest of Walnut Creek, California.
(1856) See Eaton, J. E., Grant, U. S., and Allen, H. B., Bull.
Amer. Assoc. Petrol. Geol., Vol. 25, No. 2, opp. p. 240, p. 245, 1941.
(1357) Thracia formosa Nomland, Univ. Calif. Publ. Bull. Dept.
Geol., Vol. 10, No. 14, p. 284, pl. 9, figs. 4, 4a, April 19, 1917. Loe.
2991 (UC), “Near center of SE 4 Sec. 17, T. 22S, R. 16 E. On top
of ridge south of road. Pecten coalingensis zone.”

(1358) Cited as Poromyidae by Dall, 1886.

(1359) See Dall, W. H., “Scientific Results of Explorations by
the U.S. Fish Commission Steamer Albatross. No. VII.—Prelimi-
nary Report on the collection of Mollusca and Brachiopoda ob-
tained in 1887-'88.” Proc. U.S. Nat. Mus., Vol. 12, No. 773, pp.
219-362, pls. 5-14, 1889 (issued March 7, 1890). (‘‘Poromyidae,”
pp. 284-292.)

(1360) Poromya Forbes, Rept. Brit. Assoc. Adv. Sci. for 1843, p.
191, issued 1844. Sole species, Poromya anatinoides Forbes, p.
191. “Asia Minor, Cyclades,” Aegean Sea, Recent.—Dall, Proce.
U.S. Nat. Mus., Vol. 12, No. 773, p. 289, 1889 (issued March 7,
1890).—Dall, Bartsch, and Rehder, Bernice P. Bishop Mus., Bull.
158, p. 223, 1988. "Type: Poromya anatinoides Forbes. ? = gran-
ulata Nyst and West[{endorp] (by monotypy).’’—See also, Olsson,
Mollusks of the Tropical Eastern Pacific (Paleo. Res. Inst.: Ith-
aca, New York), p. 467, 1961.

(1361) See Lamy, E., Comp. Rend. Congrés Soc. Savantes, Paris,
1925, p. 505.

(1362) SeeOdhner,N.H.—J., Mollusca,in Repts. Swedish Deep-Sea

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Exped. 1947-1948, Vol. 2, Fasc. 4, Zool., No. 22, pp. 377-379, No-
vember, 1960.

(1363) Poromya gabbiana Anderson and Martin, Proc. Calif.
Acad. Sci., Ser. 4, Vol. 4, p. 56, pl. 3, figs. 7a, 7b, December 30,
1914.

(1364) See Keen, A. M., and Bentson, H., Geol. Soc. Amer., Spec.
Papers No. 56, p. 103, 1944.

(1365) See Tegland, Nellie M., Univ. Calif. Publ. Bull. Dept.
Geol. Sci., Vol. 23, No. 3, p. 92, 1933.

(1366) Addicott, W. O., Jour. Paleo., Vol. 40, No. 3, pp. 644, 645,
May, 1966.

(1867) See Clark, A., Trans. San Diego Soc. Nat. Hist., Vol. 7,
No. 4, table opposite p. 30, 1931.

(1368) Poromya (Dermatomya) equatorialis Dall, Bull. Mus.
Comp. Zodl., Vol. 43, No. 6, p. 429, pl. 5, figs. 1, 2, October, 1908.
“U.S.S. ‘Albatross,’ station 3360, Gulf of Panama, in 1672 fath-
oms, sand, bottom temperature 42° F.; U.S.N. Mus. 122, 942. Also
at station 2793, off the coast of Ecuador, in 741 fathoms, mud,
temperature 38.4° F.”

(1369) Poromya (Dermatomya) soyoae Habe, Gen. Jap. Shells,
No. 3, p. 278, figs. 724, 728, May, 1952. [Name and figures only. |—
Habe, Illustr. Cat. Jap. Shells, No. 21, p. 158, pl. 22, figs. 7, 8, No-
vember 30, 1952 (as Dermatomya tenuiconcha soyoae). “Type lo-
cality: Off Hachinohe City Aomori Pref., (Soyé-maru St. No. 71,
444 m. in depth); off Kuji, Iwate Pref. (St. 62, 641 m. in depth);
off Kinkazan, Miyagi Pref. (St. 33, 331 m. depth), Honshu.”
(1370) Dermatomya (tenuiconcha Dall, 1913, var.?) sagamiensis
Okutani, Bull. Tokai Reg. Fish. Res. Lab., Tokyo, Japan, No. 32,
p. 32, pl. 3, fig. 3; pl. 5, figs. 8, 8a, January, 1962. Type locality:
“Sagami Bay, 700-750 m.”

(1371) Cited as Family Cuspidariidae by Dall, Bull. Mus. Comp.
Zodl., Harvard College, Vol. 12, No. 6, p. 292, September, 1886.
(1372) See Conrad, T. A., “Catalogue of the Family Anati-
nidae,” Amer. Jour. Conch., Vol. 4, Pt. 5, Neaera, pp. 56-58, 1869.
(1373) Kuroda, T., “Studies on Japanese species of Cuspidaria,”
Jap. Jour. Malacol., Vol. 15, Nos. 1-4, pp. 1-28, pls. 1 and 2, 1948.
(1374) Cuspidaria (Cardiomya) californica Dall, Bull. Mus.

381

Comp. Zodl., Vol. 12, No. 6, p. 296 (footnote), September, 1886.
“Habitat. Catalina Island, California, dredged in 16 fms., mud;
Dall, and previously Cooper, who confounded it, following Car-
penter, with pectinata.”—I. S. Oldroyd, Stanford Univ. Publ.
Univ. Ser. Geol. Sci., Vol. 1, p. 101, pl. 5, fig. 14; pl. 34, fig. 3, 1924.
Puget Sound to San Diego, California.

(1375) See “Cuspidaria (Cardiomya) oldroydi n. sp., Dall” in I.
S. Oldroyd, Publ. Puget Sound Biol. Sta., Vol. 4, p. 33, pl. 1, fig.
13, March, 1924. “Lopez Island, Wash.; Puget Sound.— Vancouver
Island to Puget Sound.”—I.S. Oldroyd, Stanford Univ. Publ. Univ.
Ser. Geol. Sci., Vol. 1, p. 101, pl. 5, fig. 13, 1924. “Type locality, Pu-
get Sound.”

(1376) See Vedder, J. G., U.S.G.S., Prof. Paper 400 B, p. B326,
1960.

(1377) See Simonova, A. A., Trans. Geol. Oil Inst., New Ser.,
Fasc. 18, p. 29, pl. 10, fig. 1, 1941.

(1378) Kuroda, T., ‘On the Verticordiidae from Japan,” Venus,
Vol. 17, No. 1, pp. 6-16, pl. 1 (figs. 1-18), and figs. 19, 20 (p. 15),
July, 1952.

(1379) See Iredale, T., Rec. Australian Mus., Vol. 17, No. 9, pp.
387-388, June 27, 1930.

(1380) See Soot-Ryen, T., Sarsia, No. 24, pp. 15-27, pls. 1-3, figs.
11-13 in text, April, 1966.

(1381) See Verticordia granulosa Ravn, Kon. Dan. Vidensk.
Selskab., Biol. Skr., Bd. 1, Nr. 1, p. 39, pl. 1, figs. 12 a-b, 18, 14 a-b,
1939. “Paléocéne de Copenhague.”

(1382) Fischer, P., “Note sur les genres Hippagus et Verti-
cordia,” Jour. de Conchyl., Vol. 8 (2nd Ser., Vol. 4), pp. 295-300,
1860; also Vol. 10, pp. 378-381, 1862.

(1383) Verticordia aequicostata Howard, Nautilus, Vol. 63, No.
4, p. 109, pl. 7, 2 figs., April, 1950. Type “from north of Angel La
Guardia Island, 90 fathoms.” [Gulf of California.]

(1884) Verticordia perplicata Dall, Proc. U.S. Nat. Mus., Vol.
12, No. 773, p. 278, pl. 8, fig. 1, issued March 7, 1890. “Hab.—U.S.
Fish Commission Station 2807, in 812 fathoms, mud, near the
Galapagos Islands; bottom temperature 38°.4 F.”

382

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

LIST OF LOCALITIES

CALIFORNIA ACADEMY OF SCIENCES

104.

105.

547.

957.

1129.
1130.
1132.
1135.
1136.
1137.
1138.
1140.

1141.
1155.

1176.

lalr(re

1178.
LTO:

1181.

1182.

1183.
1186.
1199.
1399.
1400.

1401.

Sea cliff about three miles south of La Jolla,
Pacific Beach.

Along the west margin of the peninsula which
extends into False Bay from the north, Pacific
Beach, San Diego.

Fossils from beach cliff north of Pacific Beach,
San Diego.

Pacific Beach, upper 5 to 15 feet beneath un-
conformably overlying Pleistocene beds.
Reynard Way off State Street, San Diego.
San Diego, unlocalized.

Upper beds in Pliocene section at Pacific Beach.
[= SD Loe. 34]

Between Reynard Way and Union Street, San
Diego.

South of organ in Balboa Park, San Diego.
31st Street and Logan Avenue, San Diego.
Pacific Beach, San Diego.

Sweetwater Hills, one half mile west of water
pipe house.

32nd and Woolman, San Diego.

Beds from top of hill to oyster bed at Locality
1154. Highest beds on hill west of dike.’ Top
of ridge above San Augustine Canyon east side.
About 9.6 Kilometers (6 miles) south of ranch
house. Santa Rosa Island, California.
Fossiliferous beds exposed on road going up
hill 0.3 mile (.48 kilometer) north of San Diego
well which was located at foot of Ash Street
in valley of canyon below Russ School.

Road cut on west side of hill just east of corner
of Haines Street and Tourmaline Avenue, Pacific
Beach.

At foot of Diamond Street, Pacific Beach.
[= SD Loc. 21]

Upper beds of lower portion of Pliocene section
exposed at Pacific Beach.

South slope of Mt. Soledad, above middle part
of gulch, altitude about 140 feet, about 1/3
mile (first gulch) west of Rose Canyon. [= SD
Loc. 4 and 80]

At elevation of about 90 feet in first gulch,
300-400 yards west of mouth of Rose Canyon,
south slope of Mt. Soledad.

Eagle Street just north of Quince Street, just
east of Reynard Way, San Diego.

Cliffs on east side of Reynard Way near mouth
of canyon, 100 yards off main highway, where
brickyard was located. [= SD Loc. 27]

Pacific Beach, San Diego.

100 to 200 yards south of Eocene-Pliocene
contact at Pacific Beach.

Upper beds in Pliocene section at Pacific Beach,
near Loc. 957 (CAS). [= SD Loc. 150]
First canyon west of Rose Canyon on south
slope of Mt. Soledad.

1402.

1404.
1413.
1414.
1415.
1418.
1419.
2015.

2020.
2028

12051.
12053.
12078.
12096.

12099.
12107.
12142.
12145.
12147.
12149.
28158.
28159.
28453.

28454.

28644.
28880.

28882.
28884.

28885.

28886.

28887.

28888.

About 100 m south of the west end of Laurel
Street bridge across Cabrillo Canyon, on point
between Cabrillo Canyon and a gulch running
into the canyon, Balboa Park, San Diego. [= SD
Loc. 29]

Southeast corner of India and Upas Streets,
San Diego. [= SD Loc. 75]

Beds of lower portion of Pliocene section ex-
posed at Pacific Beach.

Beds in middle portion of Pliocene section ex-
posed at Pacific Beach.

Road cut north of bridge over 26th Street
canyon, San Diego.

Northeast corner of Spruce and Thorn streets,
San Diego. [= SD Loc. 38 and 79]

Northeast corner of India and Thorn streets,
San Diego. [= SD Loc. 34]

Pacific Beach, San Diego.

Pacific Beach, San Diego.

Cliffs north of Pacific Beach, San Diego.

San Diego, unlocalized.

Pacific Beach, San Diego.

San Diego well.

San Diego, Calif. (H. Hemphill) [“‘apparently
from well in Balboa Park, San Diego, Cal.” ].
Well at San Diego.

Well at San Diego in Balboa Park.

San Diego, unlocalized.

Cedros Island.

San Diego, unlocalized.

Pacific Beach, San Diego.

Pacific Beach.

Small ravine at Pacific Beach.

Silty beds in road bank on canyon road in south-
west corner of Balboa Park, San Diego.

Cut in strata at stairway to concession, Balboa
Park, San Diego.

Pacific Beach, San Diego.

On Market Street, 1/10 mile east of Euclid
Street, in Las Chollas Valley, San Diego. [= SD
Loc. 408]

Small canyon on south slope of Mt. Soledad.
Embankment on Windsor Drive where Tourma-
line Avenue would intersect if projected, Pacific
Beach.

Small ravine in west face of terrace 250 yards
north of Mexican Boundary and 3/4 mile from
the coast (a little north of south edge of willow
patch and a farm road). [= SD Loc. 416;
UCLA 310]

200 yards south of end of Law Street, if pro-
jected, Pacific Beach.

Dosinia beds, 1/5 mile south of the Ford
Building at bottom of Cabrillo Canyon, San
Diego.

Fossiliferous strata 10 to 20 feet above the road
in the first terrace in prominent cut on west
side of the road at the lower entrance to Mount

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

28889.

28890.
28891.
28892.

28893.

Hope Cemetery, between Imperial Avenue and
the old Cuyamaca railroad (= 36th Street).
[= SD Loc. 409; UCLA Loc. 303]

Fifth ravine north (about 1/4 mile) of the
Mexican boundary, at west face of terrace 3/4
mile east of coast, the ravine debouching near
the north end of a willow patch. [= SD Loe.
417]

0.4 mile north of Broadway on Fairmount Ave-
nue, San Diego.

West shore of Bay Point near Fontera and La
Mancha streets, San Diego.

200 feet north of Mexican boundary and 3/4
mile east of coast, in east-west ravine, tributary
to a larger south north ravine at right angle,
in first terrace above Tiajuana River plain.
[= UCLA Loe. 294; SD Loc. 331]

Corner of India and Upas streets, San Diego.

SAN DIEGO SOCIETY OF NATURAL HISTORY

2.

2.

29.

34.

Northeast side of gulch at elevation of 90 feet,
300 to 400 yards west of Rose Canyon, on south
slope of Mt. Soledad.

Gulch no. 2, a little above its middle, at an eleva-
tion of about 140 feet, about 1/3 mile from Rose
Canyon highway, south slope of Mt. Soledad.
[= SD Loe. 80; CAS Loc. 1181]

Second gulch west of Rose Canyon highway, south
slope of Mt. Soledad, 30 feet higher than Loc. 4
(SD).

Fossil Canyon, just north of Telegraph Canyon,
about 1/2 mile east of Chula Vista.

About 3/8 mile up side canyon draining into
long canyon, under the words “La Nacion”’ on
U.S.G.S. topog. map of San Diego quad.
Approximately at point of intersection of 11th
and Fir streets, if projected, along old road leading
up south ridge of mesa from canyon bottom,
Balboa Park, San Diego.

West end of Diamond Street, Pacific Beach. [=
CAS Loc. 1178]

West side of hill just east of corner of Haines and
Tourmaline streets, Pacific Beach.

About 150 feet south of Eocene-Pliocene contact,
3/4 miles north of Garnet Street Pier, Pacific Beach.
In bank at side of road just east and north below
Mercy Hospital, on Sixth Street grade leading down
into Mission Valley, San Diego.

Cliffs on east side of Reynard Way near mouth
of canyon, 100 yards off main highway near old
brickyard. [= CAS Loc. 1186]

On end of point between Cabrillo Canyon and a
gulch about 100 m south of the west end of Laurel
Street bridge across Cabrillo Canyon in Balboa
Park. [= CAS Loc. 1402]

Northeast corner of India and Thorn streets, San

383

28894. In canyon below ranch one half mile north up
Aquamar Lane from Foothill Boulevard, Pacific
Beach.

31320. Market Street extension at 54th Street, San
Diego.

31356. Pacific Beach, San Diego.

33334. 100-foot bluff with fossiliferous concretions in
clay quarry at end of Arroyo Drive, San Diego.

34221. Encinitas, San Diego County.

35025. Pacific Beach, San Diego.

36384. About two feet above top of basal conglomerate
of San Diego Fm. in road cut on east side of
Cabrillo Freeway at elevation of about 225
feet, nearly opposite Mercy Hospital, San Diego

36599. Intersection of Wabash, Imperial and side street

403.

404.

entering on arroyo about 1000 feet west of
Lucky Lager warehouse, San Diego. Reworked
fossils in whitish sand.

Diego. [= CAS Loc. 1132 and 1419]

Columbia and State streets, San Diego.

Pacific Beach, unlocalized.

Northeast corner of India and Spruce streets, San
Diego. [= CAS Loc. 1418]

India Street near Spruce Street, San Diego.

About 2 miles south of Ocean Beach and about 2/3
of a mile north of the military reservation, San
Diego.

Balboa Park, San Diego.

Southeast corner of India and Upas streets, San
Diego. [= CAS Loc. 1404]

Northeast corner of India and Spruce streets,
San Diego. [= CAS Loc. 1418]

A little above middle part of a gulch 1/3 of a mile
west of Rose Canyon, south slope of Mt. Soledad
[= CAS Loe. 1181 and 1401]

Under bridge 1/2 mile east of Mission Cliffs Gar-
dens, San Diego.

Reynard Way, San Diego.

South slope of Mt. Soledad.

. Pacifie Beach. [= CAS Loc. 1400]
. San Diego, unlocalized.
. Exposure in east-west ravine tributary to a larger

south-north ravine at right angle, in first terrace
above Tiajuana River plain, 200 feet north of
Mexican boundary and 3/4 mile from the coast.
[= CAS Loc. 28892]

. Second ravine north of Rose Canyon, south slope

of Mt. Soledad.

. Lowest Pecten healeyi bed exposed just south of

ravine which is just south of Eocene-Pliocene con-
tact, Pacific Beach.

Including and above Pecten healeyi bed at Loc.
402 (SD), Pacific Beach.

Pecten invalidus bed at second ravine south of
Eocene-Pliocene contact, Pacific Beach.

384

320A.

323.

1141.
1155.

1176.

In chalky-white marl-like sediment 11 feet
thick, 110 feet back of house at Loc. 320
(LAM).

Under bridge between Fifth Street and the
Radio Station, about 160 feet from the fence
and about 350 feet from the Radio Station,
San Diego.

32nd and Woolman Avenue, San Diego.
Between Reynard Way and Union Street, San
Diego.

0.3 mile north of San Diego well on road up

UNIVERSITY OF CALIFORNIA AT LOS ANGELES

294.

295.
296.

298.
299.

300.

301.

302.

303.

305.

306.

307.

309.

310.

200 feet north of Mexican boundary in east-
west ravine tributary to larger south-north ra-
vine in first terrace above Tiajuana River plain,
three fourths mile east from the coast. [= SD
Loc. 331; CAS Loc. 28892]

Second ravine west of mouth of Rose Canyon,
south slope of Mt. Soledad. [= SD Loc. 365]
Street cut on northwest side of Fairmount, 0.4
mile north of intersection with Broadway, San
Diego.

Pacific Beach, San Diego. [= SD Loc. 402]
Pecten healeyi bed and above it, commencing
at second ravine south of Pliocene-Eocene con-
tact, Pacific Beach [= SD Loc. 404]

Coarse sandstone containing Chlamys invalida,
extending south from second ravine south of
Pliocene-Eocene contact, Pacific Beach. [= SD
Loc. 403]

Hard coarse sandstone bed exposure beginning
at third ravine south Eocene-Pliocene contact,
tact, Pacific Beach.

Road cut 0.1 mile east of Euclid Avenue on
north side of Market Street, San Diego. [= SD
Loc. 408; CAS Loc. 28880]

Between Imperial Avenue and old Cuyamaca
railroad (36th Street), San Diego. [= SD Loc.
409; CAS Loc. 28888]

“Barnacle Reef” in coquina sandstone just be-
low bottom of Sweitzer conglomerate, on spur
of mesa across Las Chollas Valley.

Float at base of railroad cut between Las
Chollas Valley and 32nd and Greeley streets,
San Diego. [= SD Loc. 412]

About a block above Market Street Bridge,
Las Chollas Valley, San Diego. [= SD Loc.
413]

Stratum with oysters in building excavation at
southeast corner of India and Upas streets,
San Diego. [= SD Loc. 415]

In small ravine facing west (a little north of
south edge of willow patch and a farm road)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

hill.

A1323. Fossil Canyon east of Chula Vista.
A2081. Pacific Beach.

P87.

Upas and India streets, San Diego.

P87. No.8325. 32nd Avenue and Woolman Street, San

Diego.

P87. No.S8339. Pacific Beach
P87. No.S8443. Southwest of the end of the bridge over

Cabrillo Canyon, Balboa Park, San Diego.

P87. No.S8442. San Diego, unlocalized.

311.
312.

331.

1382.

1383.

1384.

1385.

1386.

2359.

2420.

in west face of terrace, 250 yards north of
Mexican boundary and 3/4 mile east of coast.
[= CAS Loc. 28885; SD Loc. 416]

San Diego, unlocalized.

Second ravine north of Loc. 294, fifth ravine
north (about 1/4 mile) of the Mexican bound-
ary, at west face of terrace 3/4 mile east of the
coast, the ravine debouching near the north
end of a willow patch. [= SD Loc. 417; CAS
Loc. 28889]

San Diego, unlocalized.

Pecten bellus beds in cut bank behind a leveling
excavation back from 11th Street (eastward)
and south of a dirt road across from cobble-
stone bridge.

Macoma beds 20 feet stratigraphically above the
Pecten bellus beds and just below the terrace
gravels in cut bank behind a leveling excavation
back from 11th Street (eastward) and south of
a dirt road across from the cobblestone bridge,
San Diego.

Pecten healeyi beds in road cut north of fork
in road up ravine, opposite a grove of fir trees
and between latitude of Date and Elm streets,
San Diego.

Pecten healeyi beds in cut bank 1268 to 1410
feet along fork in road emerging just east of
Federal Building in Balboa Park Plaza, 10 to 12
feet stratigraphically below Dosinia beds at Loc.
1386 (SD).

Dosinia beds in cut bank 338 feet along ravine
road from Loc. 1385 and just below the south-
east corner of the Federal Building in Balboa
Park, San Diego.

Soft brown fine-grained sandstone outcropping
in a small canyon parallel to and about two-
tenths of a mile west of the mouth of Rose
Canyon and four tenths mile north of Garnet
Avenue (2.6 mile S. 40° E. of triangulation

station on Mount Soledad).

Soft Pliocene sands exposed in bluffs along
Pacific Beach, about 1/2 mile southeast of False
Point, La Jolla quad.

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

408.

409.

412.
413.

415.

416.

417.

446.

1142.
2359.
2407.
2912.

Road cut 0.1 mile east of Euclid Avenue on
north side of Market Street, San Diego. [= CAS
28880]

First prominent cut on west side of road, lower
entrance to Mt. Hope Cemetery, between Im-
perial Avenue and old Cuyamaca railroad (36th
Street), San Diego. [= CAS Loc. 28888; UCLA
Loc. 303]

Between Las Chollas Valley and 32nd and
Greeley streets, San Diego. [= UCLA Loc. 412]
Large concretionary lenses following bedding of
outcrop prominent in bottom of wash, about a
block above Market Street Bridge, Las Chollas
Valley, San Diego.

Oyster layer in building excavation at southeast
corner of India and Upas streets, San Diego.
[= UCLA Loc. 309]

In west face of terrace, 250 yards north of
Mexican Boundary, 3/4 mile east of coast.
[= CAS Loc. 28885; UCLA 310]

Second ravine north of Loc. 331 (SD) and fifth
ravine north of Mexican boundary (about 1/4
mile), in west face of terrace about 3/4 mile
from the coast. This ravine debouches near
the north end of a patch of willows. [= CAS
Loc. 28889]

Pacific Beach, unlocalized.

Near Fir and Boundary streets, San Diego.
San Diego, unlocalized.

Pacific Beach.

Reynard Way, San Diego.

LOS ANGELES COUNTY MUSEUM

103.
104.
107.

116.

121.

122.
124.
127.

180.
302.

302A.

West side of Reynard Way, between Curlew
and Eagle streets, San Diego.

West side of Reynard Way, between Curlew
and Eagle streets, San Diego.

100-foot bluff with scattered fossiliferous con-
cretions in clay quarry at end of Arroyo Drive,
San Diego. [= CAS Loc. 33334]

Oyster bed at corner of Dove and Maple streets,
San Diego.

On south side of the junction of Washington
Street and University Avenue ‘‘Douglas Free-
way,” continuation of Andrews Place, San
Diego.

20 to 30 feet below the end of Loring Street,
Pacific Beach.

West side of Reynard Way, between Curlew
and Kagle streets, San Diego.

Shell stratum on Wabash Freeway, Market Street
continuation, 1/4 mile south of Euclid Street,
Encanto.

2200 block on east side of La Jolla Boulevard
at the intersection with Tiras Street, San Diego.
Twenty feet of sand and silt above street level
across the street from the house at 2840 Col-
umbia Street, San Diego.

In chalky-white marl-like sediment 11 feet thick,
110 feet behind the house at 835 South 32nd
Street, San Diego.

2915.
2916.
2930.

2931.
2939.
2946.
2948.
2949.
2951.
2954.
3203.
3206.
3209.
3592.
4413.
4735.
5001.
5003.
5006.
5251.
5252.
5679.
6304.
6307.
6386.
6387.
6389.

305.

305A.

305B.
305C.

308.
309.

318.

319.

320.

385

India Street near Spruce Street, San Diego.
Reynard Way, San Diego.

Reynard Way (formerly known as “Brickyard
Canyon’), about 1/4 mile northeast of the old
brickyard, in a small gulch southeast of the
street.

Reynard Way, San Diego.

Same as Loc. 2930.

Same as Loc. 2930.

Same as Loc. 2930.

Same as Loc. 2930.

Reynard Way, San Diego.

Reynard Way, San Diego.

Kensington Park, San Diego.

Kensington Park, San Diego.

Kensington Park, San Diego.

Reynard Way, San Diego.

Juniper and Boundary Streets, San Diego.

India Street near Spruce Street, San Diego.
Soledad Mountain, San Diego.

Soledad Mountain, San Diego.

Soledad Mountain, San Diego.

Balboa Park, San Diego.

Cabrillo Canyon, Balboa Park.

Las Chollas Valley, San Diego.

Pacific Beach, San Diego.

Pacific Beach, unlocalized.

Pacific Beach, San Diego.

Pacific Beach, San Diego.

Pacific Beach, San Diego.

2400 feet east and 1350 feet south of north-
west corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meriidan (see U.S.G.S.
topog. map, San Ysidro quad., ed. 1943).
West side of next gully east of Loc. 305 (LAM)
at the same elevation: fossils in float slump and
consolidated boulders, silt and sandstone, and
silt in place.

A small pocket in gully next to 305A (LAM).
Exposure at base of hill, 100 feet west and
440 feet south of the northeast corner of Sec.
8, T. 19 S., R. 2 W., San Bernardino Base and
Meridian (U.S.G.S. topog. map, San Ysidro
quad., rev. 1953).

0.23 mile north of intersection Harbor Boulevard
and Tourmaline Street, Pacific Beach.

Two canyons east of Kate Sessions School,
approximately 0.3 mile west of Balboa Avenue
from U. S. 101, turning on to a paved road
passing in front of a pink building, San Diego.
Just above the gates and cow shed, 200 feet
from the road and 30 feet above the valley
floor, on Knox Ranch hill.

Exactly between United States-Mexico bound-
ary fence and Mr. Ericson’s (the manager’s)
house, 27 feet above the road level on the
shoulder of the second hill.

100 feet back of house No. 835, South 32nd
Street, San Diego.

386

SAN DIEGO STATE COLLEGE

31.
32.

47.

Same as Loc. 305A (LAM).

South side of Tiajuana River near mouth of Valley;
sandstone-siltstone at base of hill south of Monu-
ment Road and east of Border Naval Reservation,
east side of mouth of a prominent gully west of
Goat Canyon, southeast 1/4 Sec. 8, T. 19S., R. 2
W. (see U.S.G.S. topog. map, San Ysidro quad.,
ed. 1953). [= LAM Loc. 305A]

About six feet stratigraphically above friable sand-
stone exposed at bottom of gully at Loc. 46
(= 47) which is, south side of Tiajuana River valley;
sandstone-siltstone at base of hill south of Monu-
ment Road and east of Border Naval Reservation,
east side of prominent gully west of Goat Canyon,

222.

223.

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

southeast 1/4 of Sec. 8, T. 19 S., R. 2 W, San
Bernardino Base and Meridian (see U.S.G.S. topog.
map, San Ysidro quad., ed. 1953). [= LAM Loc.
305C]

South side of Mt. Soledad; shell bed at base of
cut in bank.

South side of Mt. Soledad; shell bed at base of
cut in bank and about five feet stratigraphically
lower than at Loc. 222 (SDSC).

UNIVERSITY OF CALIFORNIA AT BERKELEY
A-8333. Same as Loc. 305 (LAM).

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

A

Abarbatia 157 (104) [All footnote refer-
ences, which start on p. 345, are in
parentheses]

(Abarbatia) oahua, Barbatia (104)

abbotti, Chlamys (Argopecten) abietis
143, 196 pl. 34, 36

abietis abbotti, Chlamys (Argopecten)
143, 196 pl. 34, 36

Aequipecten (368)
Chlamys (Argopecten) 196 (368)
Pecten (Plagioctenium) (368)
Abra aequata 235
abrupta, Mya 329 (1277)
Panope (Panope) 328, 329 (1278)
Saxicava (979)
(Acar) illota, Barbatia 157
millifilia, Arca 158 (111)
millifilia latrinidadis, Barbatia 158
(112)
Acila 144, 147 (36)
divaricata 147
lyallii 147
mirabilis 147

Acila (Truncacila) castrensis 147-148
pl. 27

(Acila) castrensis, Nucula 148

acolasta, Macoma (Macoma) 290-291
pl. 53

Macoma moesta 291

aculeata, Anomia 223 (553)

acutilineata, Lucina (Myrtea) 247, 249
(721)

acutilineatus, Phacoides 247, 249 (724)

acutus, Cyclopecten 213, 214 (486)

adamas, Anomia 224 (558)

adamsi, Venus 277

adamsiana, Hormomya 164

Mytilus 164

adamsianus, Aeidimytilus 164-165

pl. 42
Brachidontes (Hormomya) 164
Mytilus (Horomya) 164 (153)
Scolimytilus (Aeidimytilus) 164

Adontorhina 254 (778)

aduncus, Pecten 182 (285)

Aeidimytilus 162, 164 (152)

adamsianus 164-165 pl. 42

(Aeidimytilus) adamsianus, Scolimytilus
164

aequata, Abra 235

Amphidesma 235

nuda, Aligena 236 (658)
aequicostata, Verticordia 343 (1383)
Aequipecten 188, 195, 202, 203

abietis (368)

antonitaensis 201 (391)

circularis bramkampi (376)

circularis eldridgei (377)

circularis impostor (396)

circularis invalidus 200

irradians (210)

purpuratus 200 (389)

revellei 202

Aequipecten (Leptopecten) camerella

f 204 (410)

cracens 204 (412)

_ Aequipecten (Plagioctenium) circularis

197

(Aequipecten) bellilamellatus, Pecten 203
deserti, Pecten 200
gibbus circularis, Pecten 199

INDEX

purpuratus, Pecten 198, 199
purpuratus subdolus, Pecten 201
sulcata
aequisulcata, Chlamys (Argopecten)
circularis 196, 197, 198, 199 (369,
370)
aequisulcatus, Pecten (371)
Pecten (Plagioctenium) circularis (370)
aequizonata, Lucina 249
affinis longisinuatus, Tagelus 306
Macoma inquinata 293 (1034)
plena, Macoma 293 (1027)
Agerostrea 221
ungulata 221
(Agerostrea) megodon, Ostrea 221-222
pl. 38
akihoensis, Pecten 182
akitana, Chlamys 192 (3 & 4)
alatus, Pecten 174, 183
alba, Lima 214
albaria coosensis, Spisula 312, 313
(1161)
Mactra 312-313
Spisula 312, 313
Tellina 292
albella, Lucina (734)
albensis, Nucula (25)
albertensis, Saxicava? (1244)
albicans, Pallium (262)
Pecten 177
Tellina 289
albidum, Calpodium 334
albigena, Thyasira 257
albus, Pecten 181
alcatrazensis, Spisula catilliformis 314
(1168)
aldrovandi, Panope 327
Alectryonia 221
(Alectryonia?) caboblancoensis, Ostrea
(S11)
(Alectryonia) megodon, Ostrea 221
vespertina venezuelana, Ostrea (525)
alectus, Anomia 224
aleutica, Diplodonta 253
Aligena 235 (657)
aequata nuda 236 (658)
cerritensis 236
diegoana 143, 235-236 pl. 44, 45
laevis 235, 236 (659)
redondoensis 236 (660)
striata 235
Aligena (Odontogena) borealis 236 (661)
alisoensis, Siliqua 310 (1143)
allisoni, Chione (Chione) 143, 273 pl. 51
Aloidis 322
guineensis 322
Alodis (Caryocorbula) luteola 324
nuciformis (1235)
Alodis (Corbula) gibba (1231)
alope, Placunanomia 225, 226 (673)
alta, Metis 298 (1064)
Paphia (Callithaca) tennerima 278
Protothaca (Callithaca) tenerrima 278
Tellina 298
Alucinoma 247 (720)
soyoae (720)
amethystus, Solen 304 (1101)
amicula amicula, Anadara (Anadara)
156 (96)
elongata, Anadara (Anadara) 156
(96)
Anadara (Anadara) amicula 156 (96)
Arca (96)

387

Amphidesma aequata 235
Amphiodia-Cardita 231
ampla chrysis, Panomya 330 (1292)
Panomya 330 (1286)
Amusium (Cyclopecten) pernomus 213
Ammussiopecten 209 (268, 451)
burdigalensis spinosella (451)
Anadara 152, 154, 155 (81-83)
amicula 156
devincta 156
devincta montesanoana 156
microdonta 156 (90)
montereyana 156
topangensis 156
trilineata 154-155, 157 pl. 28 (91)
trilineata calcarea 154, 155, 156-157
pl. 28 (100)
trilineata canalis 156, 157
Anadara (Anadara) amicula amicula 156
(96)
amicula elongata 156 (96)
microdonta (89)
montereyana (93)
trilineata 155, 274 (99)
trilineata canalis 157
trilineata trilineata 155
(Anadara) amicula amicula, Anadara 156
(96)
amicula elongata, Anadara 156 (96)
microdonta, Anadara (89)
montereyana, Anadara (93)
trilineata, Anadara 154-156 (99)
trilineata, Arca 155
trilineata calcarea, Arca 156
trilineata canalis, Anadara 157
trilineata trilineata, Anadara 155, 274
Anatina leana (1344)
trapezoides 336
anatinoides, Poromya (1360)
anatipes, Pecten (429)
Anatipopecten 206 (429)
andersoni, Pecten 203
Phacoides (Here) (700)
angelica, Ostrea 216, 217-218, 220 pl. 38
anguineus, Chlamys (428)
Anguipecten 205 (423)
gregoryi (423)
angularis, Yoldia 151
angulata, Lima 492, 495)
Angulus 288, 289
modestus 287
variegatus 288
(Angulus) carpenteri, Tellina 288
variegata, Tellina 288
angustifrons brevilineata, Marcia (Merci-
monia) (902)
Katherinella (Katherinella) (901)
Marcia (Mercimonia) 270 (901, 903)
Venus 270 (901)
Anisodonta peninsulare (685)
anna-eugeniae, Donax (Notodonax)
(1087)
annakensis, Cardita (Miodontiscus)
nakamurai 234 (638)
annulata desilirata, Lucina 249 (725)
Lucina (Lucinoma) 247 pl. 46
annulatus, Phacoides 247
Anodonta (518)
anomala, Mysella 239
Anomalocardia 273
(Anomalocardia) fernandoensis, Chione
5

Anomalodesmata 334 (1324)

388

Anomia 223 (558)

aculeata 223 (S53)

alectus 224

adamas 224 (558)

ephippium 223

fidenas 224 (557)

hamillus 224

lampe 224

larbas 224

limatula 224

macrochisma 225 (S75)

pacilus 224

peruviana 223-224 pl. 40, 41 (S57)

simplex 223 (556)

subcostata 224 (561)

zealandica 225
Anomiacea 222 (551)
Anomiidae 222-223 (552)
Anomya simplex 224
anser, Macoma 293 (1032)
antarctica, Saxicava 327 (1251)
antecedens, Lucina (Lucinisca) nuttalli

246 pl. 46

Phacoides nuttalli 246
Antiguamya 319 (1204)
(Antiguamya) arnoldi, Mya (1204)
antiguensis churuguarensis, Pecten (451)
Antipecten 203
(Antipecten) aoe Chlamys (402)
antiquata, Arca 154

Cumingia? 301 (1074)

Taras 252
antoni, Tellina 285
antonitaensis, Aequipecten 201 (391)
aomoriensis, Macoma 294 (1039)
Aperiploma (1344)
Apolymetis 297 (1056)

biagnulata 298

clarki (1062)

cf. A. sespeensis 297 (1059)

twinensis 298
Apolymetis (Florimetis) intastriata 297
Apolymetis (Hemimetis) plicata (1057)
approximata, Lucina (Parvilucina) 249

Phacoides (Parvilucina) (736)
aragoensis, Lucina (Here) (697)
Arca 152-153, 157

amicula (96)

antiquata 154

barbata 157

boucardi 154 (79)

canalis 156

deshayesii 156

devincta (92)

devincta montesanoana (94)

fernandezensis 153

fragilis 149

glycymeris 158

illota 157

kobeltiana 154 (78)

maculosa 154

martini rostrata 148

microdonta 154, 155 (87, 89)

montereyana (93)

noae 152, 153, 154, 157

nobilis 156

nucleus 144

pacifica 153

pectunculus 158

pilosa 158

rostrata 148, 149

schizotoma 155

sisquocensis 153, 154

sulcicosta 155

tenera (109)

tetragona 153

trilineata 156

trilineata calcarea 156
Arca (Acar) millifilia 158 (111)
Arca (Anadara) trilineata 155

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

trilineata calcarea 156
Arca (Arca) leptogrammica 154 (80)
sisquocensis 153-154 pl. 27
trilineata 155
trilineata calcarea 156
(Arca) leptogrammica, Arca 154 (80)
sisquocensis, Arca 153-154 pl. 27
trilineata, Arca 155
trilineata calcarea, Arca 156
Arca (Barbatia) balesi (110)
Arca (Byssoarca) tabogensis 157
Arca (Scapharca) trilineata 155
Arcacea 152 (69)
archon, Pecten (Pecten) 177 (261)
Arcidae 152 (70, 72-76)
Arcopagia medialis 298
unda 298
Arcoperna 170 (190)
filosa (190)
inflata (191)
arctica bilineata, Hiatella 327
bilineata, Saxicava (1259)
Glycimeris 330 (1285)
Hiatella 326-327 pl. 56 (1266)
Mya 325, 326
Nucula 151
Panomya 329, 330
Panopaea 329
Saxicava 326 (1257)
turgida, Panomya 330
Yoldia 151
Arctopratulum 262
Arctostrea 221 (542)
Arcturus 229
tudis 229
arenaria, Mya 319
arenica, Tellina (Moerella) 289 (1012)
arenosa, Pandora (Kennerlia) 335
Pandorella (Pandora) 335
aresta, Caryatis (906)
Argopecten 173, 195-196, 198, 202
gibbus (365)
solidulus 195, 196
(Argopecten) abietis, Chlamys 196 (368)
abietis abbotti, Chlamys 143, 196
pl. 34, 36
callida, Chlamys 196, 198-199, 201,
202 pl. 32
circularis, Chlamys 196, 197-198,
199 pl. 32
circularis aequisulcata, Chlamys 196,
197, 198, 199 (369, 370)
circularis bramkampi, Chlamys 198
(376)
circularis calli, Chlamys 198
coopericellus, Chlamys 201 (392)
cristobalensis, Chlamys 200 (385)
deserti, Chlamys 198, 202 (378, 379)
ericellus, Chlamys 196, 199 pl. 32
evermanni, Chlamys 200
hakei, Chlamys 196, 197, 199-200
pl. 33
imitata, Chlamys (399)
impostor, Chlamys 202 (394)
invalida, Chlamys 196, 199, 200-201
pl. 33
neahensis, Chlamys 196
purpurata, Chlamys 200 (386)
subdola, Chlamys 196, 199, 201-202
pl. 30, 35
subdolus, Pecten 201
aristata, Lithophaga 169
Armimiltha 250 (740)
arnheimi, Macoma inquinata 293 (1033)
arnoldi, Callocallista (892)
Callocardia (892)
Chlamys (Nodipecten) 172
Dosinia 266
Mya (Antiguamya) (1204)
Pitaria 268

Artemis dunkeri 267
Arthemis ponderosa 265 (878)
Arthrochlamys 187
Arvella 170 (192)
Asaphis 322
ashleyi, Pecten (Lyropecten) 210
ashleyi, Semele 143, 299-300 pl. 48
asperrima, Chione (Nioche) (930)
Nioche (Nioche) asperrina (930)
Venus (930)
Astarte orbicularis 232, 233
(Crassinella) branneri 228
Asthenodontida 319
athleta, Pecten 209 (457)
Athlopecten 209 (457)
atlanticola, Pecten 203
attenuata, Lithophaga (Labis) 170 (187)
Modiola (187)
rogersi, Lithophaga (Labis) 170 (188)
Attus 317
auana, Lima 215 (496)
auburyi, Pecten (Pecten) 177 (257)
aurantia, Dione 268
aurantiaca, Cytherea 268
Macrocallista (Megapitaria) 268
Megapitaria 269
aurora, Tellina (1058)
australis, Rochefortia 239
Avicula margaritifera (558)
Axinaea 158
barbarensis 161 (130)
modesta (124)
profunda 160
(?septentrionalis) subobsoleta 159
Axinaeoderma 158
Axinola 143, 159
(Axinola) grewingki, Glycymeris 159-
160, 161 pl. 27
profunda, Glycymeris 159, 160-161
pl. 27
Axinopsida 254, 255, 257
serricata 257-258 pl. 44 (808)
Axinopsis 257
orbiculata 257
ovata 258
sericatus 257 (807)
viridis 258 (805)
(Axinulus) inequalis, Cryptodon (791)
Axinus gouldii 256
sarsii (802)
B

bakeri diazi, Pecten 177 (255)
Pecten 177

balboae, Leda (53)
Nuculana 151 (53)

balboana, Nucula (Ennucula) 143,

145-146 pl. 27

balesi, Arca (Barbatia) (110)
Barbatia 158

balthica, Macoma 293

Bankia 334 (1321)

Barbarca 157 (105)

(Barbarca) hua, Calloarca (105)

barbarensis, Axinaea 161 (130)
Cryptodon (801)
Glycymeris 161 (131)
Psephidia 281
Thyasira 257 (801)

barbata, Arca 157

Barbatia 152, 157
balesi 158

Barbatia (Abarbatia) oahua (104)

Barbatia (Acar) illota 157
milifilia latrinidadis 158 (112)

Barbatia (Fugleria) illota 157-158 pl. 27
pseudoillota 157, 158 (108)
tenera 158

(Barbatia) balesi, Arca (110)

barbatus, Lithodomus 168

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Barnea 330
Basterotella 241
(Basterotella) ecudoriana, Basterotia
242 (684)
floridana, Basterotia 241
hertleini, Basterotia 241-242 pl. 57
Basterotia 241
californica 242 (688)
corbuloides 241
peninsularis 242 (685)
Basterotia (Basterotella) ecuadoriana
242 (684)
floridana 241
hertleini 241-242 pl. 57
Bathyarca 152
bavayi, Pecten 203
beali, Pecten (Pecten) 178, 180 (273)
bechei, Cardium 262 (853)
bella, Janira 174, 176
Lucina 245, 247
bellilamellata, Chlamys (Leptopecten)
203 pl. 32
Se uatus, Pecten (Aequipecten)
0

Pecten (Chlamys) 203
bellotii, Nucula (Ennucula) 146 (29, 30)
bellus hemphilli, Pecten 175, 177
hemphilli, Pecten (Janira) 175, 177
hemphilli, Pecten (Pecten) 175 (254)
Pecten (Pecten) 174-177, pl. 30, 32
text fig. 7 (253)
slevini, Pecten 177
sleveni, Pecten (Janira) (260)
benedicti, Hinnites 212 (474)
benedictus, Pecten 181, 182
one colvillensis, Chlamys (Chlamys)
95

Panomya 329, 330 (1301)
Panomya cf. P. 329-330 pl. 56 (1300)
bernardi, Pseudosaxicava (1245)
besseri, Pecten 178
biangulata, Apolymetis 298
Florimetis 298 pl. 53
Scrobicularia 298 (1065, 1066)
biaperta, Hiatella 325, 326
bicarinata, Didonta 325, 326
Pandora (Kennerlia) 335
bifurcatus, Mytilus 165
obsoletus, Septifer 166 (156)
Septifer 165-166 pl. 42
bighopensis, Schizothaerus nuttallii
(1197)
bilineata, Hiatella arctica 327
Saxicava arctica (1259)
Venus 274
bilirata, Pandora (Pandorella) 335 pl. 47,
48

bilocularis, Brachidontes (Septifer) 165
Mytilus 165
Septifer 165
bimaculatus, Heterodonax 320
binghami, Sphenia 321
bipalmulata, Teredo 334
biplicata, Olivella 267
biradiata, Corbula (Caryocorbula) 325
(1238)
bisecta, Thyasira 255
Venus 255
Blanckenhornia 183 (292)
(Blanckenhornia) oweni, Pecten (292)
bodegensis, Tellina (Peronidia) 289-290
pl. $3 (1015)
bodenbenderi, Pecten 183
Bontaea (1344)
(Bontaea) praetenue, Cochlodesma (1344)
borealis, Aligena (Odontogena) 236 (661)
Cardita 229
Lucina (718)
Lucinoma 246, 247 (718, 719)
Ostrea 218

Venericardia 229, 230
borneensis, Conus 267
Bornia 235, 238
corbuloides 238
luticola 237
sebetia 238
Bornia (Temblornia) frankiana 143, 238-
239 text fig. 11
keenae (672)
triangulata 238
bosei, Pecten 178, 180 (275)
Botulina 168
denticulata 169
opifex 169
Botulopsis 170
boucardi, Arca 154 (79)
bowersi, Pecten 183
Brachidontes 164, 165 (150)
puniceus 166
Brachidontes (Hormomya) adamsianus
164
Brachidontes (Septifer) bilocularis 165
Be) playasensis, Modiolus
(152)

bradleyi, Corbula (Varicorbu la) cf. 324
(1237)
bramkampi, Aequipecten circularis (376)
Chlamys (Argopecten) circularis 198
(376)
branneri, Astarte (Crassinella) 228
Crassinella 228-229 pl. 43
brevilineata, Marcia (Mercimonia)
angustifrons (902)
Venus 270 (902)
brevis, Solen 307
brioniana, Spisula falcata 314
brockworthensis, Panope 327
bulla, Sphaerella (764)
burdigalensis, Pecten (451)
spinosella, Amussiopecten (451)
buttoni, Tellina (Oudardia) 289
buwaldi, Petricola 283, 284 (981)
Byssoarca 153
illota 157
lima (103)
zebra 153
(Byssoarca) tabogensis, Arca 157

Cc
caboblancoensis, Ostrea (Alectryonia?)
217 (511)
Cadella 284, 286 (1004)
lubrica 287
(Cadella) salmonea, Tellina 286-287
pl. 53
caelata, Leda 150
Nucula 150
caerulescens, Psammobia depressa 304
cahuitensis, Nucula 147 (34)
caimita, Ostrea messor 222
calaverasensis, Pecten (Patinopecten)
hay wardensis 185 (299)
calcarea, Anadara trilineata 154, 155,
156-157, pl. 28 (100)
Arca (Anadara) trilineata 156
Arca (Arca) trilineata 156
izurensis, Macoma (Macoma) 292
longisinuata, Macoma (1024)
Macoma (Macoma) 291, 292 (1023)
obliqua, Macoma (1024)
Tellina 290, 291
yokohamaensis, Macoma 292 (1022)
calcitrapoides, Cardium (Cardita) (628)
californiana, Venus 279
californianus, Solecurtus 306
Tagelus (Tagelus) 306-307
californica, Basterotia 242 (688)
Codakia 247
Cryptomya 319-320, 321 pl. 55
Cumingia 301, 302

389

Cumingia cf. C. 301-302
Cuspidaria (Cardiomya) 343 (1374)
Cyclocardia 231 (617)
Cypricardia 333
Lucina (Epilucina) 247-248 pl. 46
Lucina (Myrtea) 245, 247
Mactra 316
magna, Cryptomya 319, 320-321
pl. 54, 55
Mya (Cryptoma) 320
Saxicava 283
Sphenia 301, 319
Transennella 281 (974)
Venericardia (Cyclocardia) 23] (617)
californicus, Donax 302-303
Ensis 309, 310 (1139)
Gobraeus 305
Pecten 183
Phacoides 247
californiensis, Chione (Chione) 181, 274
(931)
gealeyi, Chione (Chione) 273 (929)
Venus (931)
calkinsi, Saccella 151 (54)
calli, Chlamys (Argopecten) circularis 198
callida, Chlamys (Argopecten) 196,
198-199, 201, 202 pl. 32
callidus, Pecten (Plagioctenium) 198 (374)
callimene, Leda (Jupiteria) (51)
Nuculana (Saccella) 151 (51)
Callista newcombiana 268
sp. indet. 268
subdiaphana 269
subdiaphana pedroana 270
Callithaca 276, 277
? cf. C. staminea (951)
(Callithaca) tenerrima, Protothaca
277-278, 279 pl. 51, 52
tennerima alta, Paphia 278
tenerrima alta, Protothaca 278-279
text fig. 12
Calloarca (Barbarca) hua (105)
Callocallista arnoldi (892)
Callocardia arnoldi (892)
Callucina 247 (729)
Callucinella 248 (734)
Calpodium 334
albidum 334
camerella, Aequipecten (Leptopecten)
204 (410)
cameronis, Spisula 315 (1174)
Camptochlamys 172
canalis, Anadara (Anadara) trilineata 157
Anadara trilineata 156, 157
canalis, Arca 156
cancellata, Venus 272
cancellosus, Patinopecten oregonensis (300)
candeana, Diplodonta 254
capax, Lutraria 318 (1192)
Tresus (1195)
Cardiacea 258 (810)
Cardiidae 258 (811)
cardiiformis, Hippagus 343
Verticordia 343
Cardiomya 342
gouldiana 342
cf. C. pectinata 343
(Cardiomya) californica, Cuspidaria 343
(1374)
oldroydi, Cuspidaria 343 (1375)
pectinata, Cuspidaria 342-343 pl. S57
Cardita 229 (605, 626)
borealis 229
corbis 232, 233
monilicosta 230
monilicosta ochotica 231 (619)
naviformis 232 (627)
occidentalis 230
aff. C. occidentalis 231 (612)
perplana (631)

390

redondoensis (622)
scalaris 230, 231 (623)
variegata 232
ventricosa 229, 230, 231 (611)
ventricosa redondoensis (622)
Cardita (Carditamera) carpenteri 232
subquadrata 232
Cardium (Cerastoderma) corbis (841)
cf. corbis (838)
Cardita (Cyclocardia) ventricosa monter-
eyensis (621)
Cardita (Glans) trapezia 232
Cardita (Miodontiscus) makamurai
annakensis 234
nakamurai annakensis (638)
prolongata 233 (635)
(Cardita) calcitrapoides, Cardium (628)
Carditacea 229 (601)
Carditamera 232
(Carditamera) carpenteri, Cardita 232
subquadrata, Cardita 232
Carditidae 229
carditoides, Petricola (Rupellaria) 283-
284 pl. 44 (982)
Saxicava 283
Cardium 258-259 (822)
bechei 262 (853)
centifilosum 263
corbis 261
costatum 258, 259
edule (823, 834)
hillanum 262
isocardia (824)
laeve 236
meekianum (843)
aff. C. meekianum 261 (833)
modestum 262
?modestum centifilosum 263
nuttalii 260, 261
oblongum (835)
quadrigenerium 259
quadrigenarium fernandoensis 260
(829)
richardsoni 263 (857)
rubrum 236
samarangae 262
semiasperum 262
shinjiensis (848)
weaveri (851)
Cardium (Cardita) calcitrapoides (628)
Cardium (Dallocardia) quadragenarium
259-260 pl. 46
Cardium (Mexicardia) procerum 260
Cardium (Trachycardium) gorokuense
260 (832)
vaqueroensis 260 (831)
caribaeus, Solen 306
carinata, Ostrea 221 (S42)
caroli, Mesopeplum (427)
carpenteri, Cardita (Carditamera) 232
modiolus 167 (170)
Tellina (Angulus) 288
Tellina (Moerella) 288-289
carrizoensis, Pecten (Pecten) 178, 179
Caryatis 267
aresta (906)
(Caryocorbula) biradiata, Corbula (1238)
luteola, Alodis 324
luteola, Corbula 324
nuciformis, Aloidis (1235)
Caryocorbulinae 323
castor, Nucula 145
castrensis, Acila (Truncacila) 147-148
pl. 27 (37
Nucula (Acila) 147, 148

catalinae, Chlamys (Lyropecten) estrellanus

Pecten (Lyropecten) estrellanus (463)

cataractes, Pecten (Euvola) 181
catilliformis alcatrazensis, Spisula 314

LEO GEORGE HERTLEIN AND U.S. GRANT, IV

(1168)
Mactra (Spisula) 313, 315
Spisula cf. S. 314 (1167)
Spisula (Mactromeris) 312, 313-314,
316 pl. 54
caucanus, Pecten circularis 198 (382)
caudiva, Crenella 171 (197)

caurinus, Pecten (Patinopecten) 172, 182,

183, 185
ceciliae, Pecten (Propeamussium) (481)
Cemoria crucibuliformis 335
centifilosa, Protocardia 263
centifilosum, Cardium 263
Cardium ?modestum 263
Nemocardium (Keenaea) 263-264
pl. 46
richardsoni, Nemocardium 264
centrifuga, Lucina nuttalli 245
centrifugus, Phacoides (Lucinisca)
nuttallii (709)
cepio, Placunanomia 225, 226 (572)
Cerastoderma 261 (834)
meekianum (843)
(Cerastoderma) corbis, Cardium (841)
cf. corbis, Cardium (838)
corbis, Laevicardium 261
Ceropsis 234
minima 234
cerritensis, Aligena 236
cerrosensis, Chlamys (Lyropecten) 200,
209-211 pl. 34, 36
Lyropecten (s. s.) estrellatus 210
Ostrea 220, 221, 222
Ostrea megodon 222 (544)
Pecten 210, 220
Pecten (Lyropecten) 210
Pecten (Plagioctenium) 210
Chaceia ovojdea 333
Chama 227 (587, 588)
chilensis 228 (591)
cristatella 227
dosin 264, 265
frondosa 227
glycymeris 158
lazarus 227 (587)
pellucida 227-228 pl. 43 (S590)
thaca 276
Chamacea 226 (583)
Chamidae 226 (584)
chenui, Gregariella 168-169 pl. 41, 42
Modiola (Gregariella) 168
Mytilus (Modiola) 168, 169
childrenae, Miltha (Miltha) 249, 251
childreni, Lucina (Miltha) 249, 250, 251
Phacoides (Miltha) 250, 251
chilensis, Chama 228 (591)
chinensis, Neaera 341
Chione 264, 272-273, 274 (927)
californiensis 181, 274 (931)
dysera 272
elsmerensis 275 (938)
euglypta 276 (948)
fernandoensis 275, 276 (940)
fluctifraga 273
gallina 272
laeta 172
lordii 280 (936)
margaritana 275 (933, 935)
mariae 276 (943)
panzana 275 (934)
schencki 275 (937)
securis 274, 276
semiplicata 275 (932)
undatella 274
undatella taberi 274
vickeryi 275 (936, 937)
Chione (Anomalocardia) fernandoensis
275
Chione (Chione) allisoni 143, 273 pl. 51
californiensis (931)

californiensis gealeyi 273 (929)

undatella 274

cf. C. (C.) undatella 273-274
Chione (Nioche) asperrima 273 (930)

Chione (Securella) kanakoffi 143, 274-276

pl. 49, 51
securis 274
(Chione) allisoni, Chione 143, 273 pL. 51
californiensis, Chione (931)

californiensis gealeyi, Chione 273 (929)

undatella, Chione 274
cf. C. (C.) undatella, Chione 273-274
Chionista 273
Chionopsis 274
chiripanica, Lucina (Lucinoma) 246
Chironia 236
laperousii 236, 237
suborbicularis 237
chironii, Kellia laperousii 237 (670)
chishimana, Penitella 333, 334
Pholadidea (Penitella) (1317)
Chlamydella 213 (482)
Chalmydina 187
Chlamys 173, 187-188, 205, 211 (316)
akitana 192 (344)
anguineus (428)
cinnabarina 187
circularis 196, 202 (396)
circularis aequisulcata 196
circularis-gibba-irradians 196
condylomata 205
condylomatus 172
durhami 192 (343)
eborea sensecens 202 (397)

eborea senescens walkerensis 202 (398)

eboreus walkerensis (398)
etchegoini (431)
etchegoini parmeleei 206
gibba 198 (371, 372)
gibba-circularis 196, 198
hastata 189, 190, 191
hastata pugetensis 191
hertleini 193
imanishii 195 (359)
imitata 202 (399)
ingeniosa (322)
ingeniosa tanakai 195 (360)
islandica 199, 191, 193
islandica hindsi 195 (355)
islandicus jordani (338)
jordani 194
kaneharai 190
kincaidi 195
miyatokoensis 190 (329)
monotimeris 202
morani 208
nipponensis 172
nisataiensis 192 (344)
nodosa 209
odontata 189 (327)
opuntia 193
parmeleei 206, 207
purpurata 196
rubida 192, 193
rubida jordani 192 (341)
sacyi 203 (403)
squamosa decoriata 189
tamurae 193 (346)
tournali 209
Chlamys (Antipecten) sacyi (402)
Chlamys (Argopecten) abietis 196 (368)
abietis abbotti 143, 196 pl. 34, 36
callida 196, 198-199, 201, 202 pl. 32
circularis 196, 197-198, 199 pl. 32
circularis aequisulcata 196, 197, 198,
199 (369, 370)
circularis bramkampi 198 (376)
circularis calli 198
coopericellus 201 (392)
cristobalensis 200 (385)

i

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

deserti 198, 202 (378, 379, 396)

eldridgei 198 (377)

ericellus 196, 199 pl. 32

evermanni 200

hakei 196, 197, 199-200 pl. 33

imitata (399)

impostor 202 (294)

invalida 196, 199, 200-201 pl. 33

neahensis 196

purpurata 200 (386)

subdola 196, 199, 201-202 pl. 30, 35
Chlamys (Chlamys) beringiana colvillensis

hastata 188-189 pl. 33
hastata ellisi 143, 188, 190-191 pl. 31,
34
hastata hericius 199, 189-190, 191 pL
33
jordani 188, 191-192 pl. 30, 32
ef. C. (C.) jordani 191, 192 pl. 32
opuntia 188, 192-193 pL. 30
rubida 188, 193-195 pl. 35
Chlamys (“Chlamys’’) pugetensis (333)
Chlamys (Leptopecten) bellilamellata
203 pl. 32
desultoria 203 (406)
latiaurata 203-204 pl. 35
cf. latiaurata 204 (411)
latiaurata delosi 203 (404)
monotimeris 203, 204
Chlamys (Lyropecten) cerrosensis 200,
209-211 pl. 34, 36
crassicardo 205, 211 (465)
estrellanus 205, 210 (461)
estrellanus catalinae 211
estrellanus terminus 211 (462)
gallegosi 211
miguelensis submiguelensis 209
Chlamys (Nodipecten) arnoldi 172
nodosa 205
nodulifera 205
subnodosa 205
subnodosus intermedius 209 (456)
Chlamys (Swiftopecten) cosibensis 205
(419)
donmilleri 207 (437)
etchegoini 207
heteroglypta 205
kindlei 205, 208
nutteri 208
paineleel 206-208 pl. 31, 37 text fig.
0

parmeleei etchegoini 207

swiftii 172, 205, 208

wattsi 207, 208

(Chlamys) hindsii jordani, Pecten (342)

hindsii kincaidi, Pecten 192, 195 (340)

hindsii navarchus, Pecten 194

hindsii, Pecten 193, 194, 195

islandicus picoensis, Pecten 194 (349)

islandicus pugetensis, Pecten (333)

islandicus venturaensis, Pecten 195

jordani, Chlamys 188, 191-192 pl. 30,
32 (339)

cf. C. (C.) jordani 191, 192 pl. 32

kindlei, Pecten 207 (436)

latiauritus, Pecten 204

latiauritus delosi, Pecten (404)

lawsoni, Pecten 189 (320)

miyatokoensis, Pecten (329)

multirugosus, Pecten 211, 212

multirugosus crassiplicatus, Pecten
(471)

nutteri, Pecten 205, 207 (433)

opuntia, Chlamys 188, 192-193 pl. 30

opuntia, Pecten 192

parmeleei, Pecten 206

pugetensis, Chlamys (333)

rubida, Chlamys 188, 193-195 pl. 35

rubidus, Pecten 194

venturaensis, Pecten 194 (350)
washburnei venturaensis, Pecten (350)
wattsi, Pecten 207 (434)
wattsi morani, Pecten 207 (435)
chrysis, Panomya ampla 330 (1212)
churuguarensis, Pecten antiguensis (451)
Ciclopecten 213
peloritanus 213
ciliatum, Clinocardium 262
cinnabarina, Chlamys 187
Circe (Lioconcha) newcombiana 268
circularis, Aequipecten (Plagioctenium)
LOFT,

aequisulcata, Chlamys (Argopecten) 196
196, 197, 198, 199 (369, 370)
aequisulcatus, Pecten (Plagioctenium)
(370)
bramkampi, Aequipecten (376)
bramkampi, Chlamys (Argopecten)
198 (376)
calli, Chlamys (Argopecten) 198
caucanus, Pecten 198 (382)
Chlamys (Argopecten) 196, 197-198,
199, 202 pl. 32 (396)
cornellanus, Pecten 198 (380)
eldridgei, Aequipecten (377)
-gibba-irradians, Chlamys 196
impostor, Aequipecten (396)
invalidus, Aequipecten 200
Pecten 181, 196, 197, 267
Pecten (Aequipecten) gibbus 199
Pecten (Plagioctenium) 197
venezuelanus, Pecten 198 (381)
claibornensis, Cyclas (739)
Claibornites 247
clallamensis, Solen 309 (1131)
clarki, Apolymetis (1062)
Tagelus 307 (1123)
clemensae, Pecten 195
Clementia 269
obliqua 270 (906)
subdiaphana 269
Clementia (Compsomyax) subdiaphana
270
aff. subdiaphana 270 (909)
subdiaphana yazawaensis 270 (908)
Clidiophora punctata 336
Clinocardium 258, 259 260-261 (836,
837)
ciliatum 262
meekianum 261 (843)
meekianum myrae 261 (844)
nomurai 262 (847)
nuttallii 261-262 pl. 46
aff. C. nuttallii (838)
pristinum (838)
shinjiense 262 (848)
Cnestrium 152
coalingaensis, Pecten (Pecten) 180, 182,
195 (283, 294, 357)
coalingensis, Glycymeris 159, 160
Mytilus (Mytiloconcha) 163
Mytilus (Mytiloconcha) cf. M. (M.)
(148)
n. var.?, Mytilus 164
sternbergi, Mytilus (Crenomytilus)
143, 163-164 pl. 41
coarctata, Crenella (177)
Gregariella 169
Cochlea corbis 261
gilva 272 (926)
cochlear, Ostrea 216 (502)
Cochlodesma 338 (1344)
leana (1344)
leana floridana 338 (1343)
Cochlodesma (Bontaea) praetenue (1344)
cocosensis, Cyclopecten 214
Pecten (Cyclopecten) (485)
Codakia californica 247
codercola, Pecten soror 178, 180 (278)

391

coelata, Leda 150
Nucula 150
cognata, Florimetis 298 (1061)
Lutricola (1061)
colombiensis, Ostrea messor 222
colon, Placunanomia 225
columbella, Lucina (698, 699)
columbianum, Phacoides 249 (726)
colvillensis, Chlamys (Chlamys) beringiana
195
communis, Lithophagus 169
commutata, Leda 149
Nucula 149
commutatus, Pecten 195, 196
compactus, Pecten 197
complanata, Corbula 324
compressa, Nucula 145
Tellina 287
Compsomyax 264, 269 (895)
subdiaphana 269-270 pl. 47, 57 (893)
(Compsomyax) aff. subdiaphana,
Clementia 270 (909)
subdiaphana, Clementia 270
subdiaphana, Venerella (905)
subdiaphana yazawaensis, Clementia
270 (908)
concamerata, Pholas 333
concava, Nucula 149
concentrica, Dosinia (Dosinia) 265
venus 265
conchaphila, Ostrea 219 (519)
palmula, Ostrea (517)
Conchocele 255
disjuncta 255
condylomata, Chlamys 172, 205
condylomatus, Pecten (Nodipecten) 209
conradi, Penitella 332-333 (1311)
conradiana, Cytherea (Transennella?) 281
conspicuus, Ischnochiton 240
constricta, Macoma 297 (1060)
contabulata, Tellina 293 (1030)
contorta, Lucina (738)
Conus borneensis 267
Convexopecten 180
(Convexopecten) josslingi, Pecten 180
cooperi kovatschensis, Yoldia 152 (68)
ochotensis, Yoldia 152 (65, 67)
Pecten (Plagioctenium) 200, 201 (393)
tenuissima, Yoldia (64)
Yoldia 151, 152
Yoldia (Kalayoldia) cf. Y. (K.) (61)
coopericellus, Chlamys (Argopecten)
201 (392)
cooperii supramontereyensis, Yoldia
151, 152 (63)
tenuissima, Yoldia 152 (64)
coosensis, Pecten (Lituyapecten) 187
(314)
Pecten (Patinopecten) (314)
Spisula albaria 312, 313 (1161)
copelandi, Macoma 297
Corbis 227 (588)
corbis, Cardita 232, 233
Cardium (Cerastoderma) 261 (841)
Cardium (Cerastoderma) cf. (838)
Cochlea 261
Laevicardium (Cerastoderma) 261
corbicula, Venus 266
Corbula 149 322-323 (1223, 1225, 1238)
biradiata 325 (1238)
complanata 324
gallica 322
gibba 323
laevigata 322
luteola rosea 324
luticola 321, 322
margaritacea 322, 336
mediterranea 324
nuciformis 324 (1235)
quadrata 241

392

radiata (1234)
speciosa 324 (1234)
striata 322
sulcata 322
Corbula (Caryocorbula) biradiata (1238)
luteola 324
Corbula (Corbula) gibbiformis 323
Corbula (Lentidium) luteola 324-325
pl. SS
Corbula (Varicorbula) cf. bradleyi 324
(1237)
gibbiformis 323-324 pl. 57
granti 324 (1236)
(Corbula) gibba, Aloidis (1231)
gibbiformis, Corbula 323
Corbulacea 322 (1221)
Corbulidae (1222, 1223, 1224)
corbuloidea, Thracia 338
corbuloides, Basterotia 241
Bornia 238
Corbulomya 324
mediterranea 324
cordieri, Petricola 279
Venerupis 279
Coripia 233 (633)
cornea, Diplodonta (Felaniella) 253-254
pl. 43
Lucina 253
cornellanus, Pecten circularis 198 (380)
cornucopiae, Lopha (540)
cortesii, Hinnites 211
cortesyi, Hinnites 212
corteziana, Glycymeris 160 (126)
cordieri, Petricola 279
Venerupis 279
Coripia 233 (633)
cornea, Diplodonta (Felaniella) 253-254
pl. 43
Lucina 253
cornellanus, Pecten circularis 198 (380)
cornucopiae, Lopha (540)
cortesii, Hinnites 211
cortesyi, Hinnites 212
corteziana, Glycymeris 160 (126)
cosibensis, Chlamys (Swiftopecten) 205
costata, Petricola 282
costatum, Cardium 258, 259
cracens, Aequipecten (Leptopecten)
204 (412)
crassa, Hinnites 211, 212 (470, 472)
Hinnites cf. H. 212 (473)
Crassatellacea 228 (592)
Crassatellidae 228
crassatelloides, Cytherea (Tivela) 266
Cytherea (Trigonella) 266, 267
Tivela 267
crassicardo, Chlamys (Lyropecten) 205,
211 (465)
Lyropecten 208
Pallium (465)
crassicosta, Venus 756 (950)
Crassinella 228
branneri 228-229 pl. 43
dalli (593)
martinicensis 228
mexicana 229 (597)
cf. C. mexicana 228
pacifica 229 (597)
quintinensis 229 (598)
sp. (594)
Crassatella (Pseuderiphyla) remiensis
(593)
(Crassinella) branneri, Astarte 228
crassiplicatus, Hinnites multirugosus 212
(417
Pecten (Chlamys) multirugosus (471)
Crassostrea virginica (505)
crassus, Pecten 212
Crenella 162, 170-171
caudiva 171 (197)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

coarctata (177)
decussata 170, 171
divaricata 171 (193)
ecuadoriana 171 (195)
ecuadoriana santiaga 171 (196)
elliptica 170
inflata 171 pl. 41
Crenomytilus 162, 163
(Crenomytilus) coalingensis sternbergi,
Mytilus 143, 163-164 pl. 41
cribraria, Lucina 244
Cricompholos 264
crispa, Hinnites 212 (475)
Ostrea 211
crispata, Mya 331
Thurlosia 331
Zirfaea 331
Zirphaea 331
crispatus, Pholas 331
crista-galli, Lopha ($40)
Mytilus ($40)
Ostrea (540)
cristatella, Chama 227
cristobalensis, Chlamys (Argopecten) 200
(385)
Pecten (385)
crucibuliformis Cemoria 335
cryphia, Periploma 337, 338 (1342)
stenopa, Periploma 337
Crypton 317
barbarensis (801)
flexuosus 255, 256
gouldii 255
incognita 319
marionensis 256 (795)
planus 256 (790, 791)
serricatus 257
verticordia 343
Cryptodon (Axinulus) inequalis (791)
Cryptomya 319 (1208)
californica 319-320, 321 pl. 55
californica magna 319, 320-321 pl. 54,
55

magna 320, 321
oregonensis (1213, 1214)
quadrata (1212)
quadrata vancouverensis 319
(Cryptomya) californica, Mya 320
incognita, Mya (1211)
crystallina, Tellina 334
Cucullaearca 157 (103)
Cultellidae 311
Cultellus 310
Cumingia 299, 300-301 (1081)
antiquata 301 (1074)
californica 301 (1074)
cf. C. californica 301-302
densilineata 301
elegans 302
keittensis 301
lamellosa 301, 302 (1080)
mutica 301
tellinoides (1077)
cumingiana, Ostrea 216 (513)
Ostrea (Lopha) 216
cumingil, Septifer 166 (157)
curvata, Penitella 333
Cuspidaria 341-342 (1372, 1373)
cuspidata 342
pectinata (1374)
typus 342
Cuspidaria (Cardiomya) californica
343 (1374)
oldroydi 343 (1375)
pectinata 342-343 pl. 57
Cuspidariidae 341 (1371)
cuspidata, Cuspidaria 342
Neaera 342
Tellina 342
Cyathodonta 337, 338, 339

formosa 324 (1357)
weaveri 339 (1355)
Cyclas claibornensis (739)
Cyclocardia 229
californica 231 (617)
inflata 231 (624)
monilicosta 231 (614)
occidentalis 230-231 pl. 43
stearnsii 231 (616)
ventricosa 230, 231 pl. 43
ventricosa montereyensis 231 (621)
ventricosa redondoensis 231 (622)
(Cyclocardia) californica, Venercardia
(617)
inflata, Venericardia (624)
stearnsii, Venericardia (616)
ventricosa montereyensis, Cardita
(621)
Cyclopecten 173, 213
acutus 213, 214 (486)
cocosensis 214
favus (482)
incubans 213
pernomus 213-214
postulosus 213
(Cyclopecten) cocosensis, Pecten (485)
pernomus, Amusium 213
pernomus, Pecten 213
rotundus, Pecten 213
Cycochlamys 213
Cycopecten 213
cygna, Thyasira 256 (792)
cymata, Psephidia 281, 282 (964)
cypria, Venus (943)
Cypricardia 232
californica 333
Cyprimeria 244
Cytherea aurantiaca 268
crassatelloides 266
excavata (704)
newcombei (895)
oregonensis 270
staminea 276
straita 267
squalida 268
sugillata 274
tripla 266
tumens 266
virginea 267
Cytherea (Tivela) crassatelloides 266
Cytherea (Transennella?) conradiana
281
Cytherea (Trigonella) crassatelloides 266,
267

D
dactylus, Lithodomus 169
dalcifer, Spondylus (177)
dalli, Crassinella (593)
Dallocardium 258, 259
(Dallocardia) quadragenarium, Cardium
259-260 pl. 46
davisi, Tellina (1003)
Decatopecten 205 (422)
decipiens, Pododesmus 224
decoriata, Chlamys squamosa 189
decussata, Crenella 170, 171
Sphenia 321
decussatus, Mytilus 170
delosi, Chlamys (Leptopecten) latiaurata
203
Pecten (Chlamys) latiauritus (404)
demiurgus, Pecten (Plagioctenium) 198
(383)
densilineata, Cumingia 301
densilirata, Lucinoma annulata (725)
dentata, Janira 178, 181
dentatus, Pecten (Pecten) 178, 181
denticulata, Botulina 169
Gregariella 169 (176)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Macoma 295
Modiolaria (175)
denticulatus, Pecten 189 (325)
depressa caerulescens, Psammobia 304
livida, Psammobia 304
normalis, Psammobia 304
Psammobia 304
Tellina 304
Dermatomya 340
mactroides 340
tenuiconcha 341 pl. 56
tenuiconcha sagamiensis 341 (1370)
tenuiconcha soyoae 341 (1369)
(Dermatomya) equatorialis, Poromya
340 (1368)
mactroides, Poromya 340
(Dermatomya) soyae, Poromya (1369)
tenuiconcha, Poromya 341
deserti, Chlamys (Argopecten) 198, 202
(378, 379, 396)
Pecten (378)
Pecten (Aequipecten) 200
Pecten (Plagioctenium) (379)
deshayesii, Arca 156
desilirata, Lucina annulata 249
desultoria, Chlamys (Leptopecten) 203
(406)
devincta, Anadara 156
Arca (92)
montesanoana, Anadara 156
montesanoana, Arca (94)
diazi, Pecten bakeri 177 (255)
pps) subula, Lithophaga 170 (184,
5)

Didimacar 157 (106)
repenta (106)
Didonta 325
bicarinata 325, 326
diegensis, Pecten (Pecten) 178, 179, 180
(269)

Pecten cf. P. 179
diegoana, Aligena 143, 235-236 pl. 44, 45
Dosinia (Dosinia) ponderosa 143,
265-266 pl. 47, 49, 51
dilleri, Patinopecten (Lituyapecten) 187
Patinopecten (Lituyapecten) cf. P. (L.)
187

Pecten 187 (313)
Pecten (Lituyapecten) 186-187
pl. 35
Pecten (Lyropecten) 186
Pecten (Patinopecten) 186
variety, Pecten 187
Diluvarea 154
Dione 268
squalida 268
Diplodonta 252 (759-761)
aleutica 253
candeana 254
cornea 254
griesensis 253
harfordi 254 (775)
impolita 253 (770)
lupinus 252
cf. orbella 253 (767)
parilis 254
sericata 254
stephensoni 254 (776)
tellinoides 254
trigonula 252
Diplodonta (Diplodonta) orbella 252-253
pl. 55, 57
Diplodonta (Felania) rosea 252
Diplodonta (Felaniella) cornea 253-254
pl. 43

usta 253
(Diplodonta) orbella, Diplodonta 252-
253 pl. 55, 57
Diplodontidae 251-252 (757)
directa, Volsella (168)

directus, Modiolus 167 (164-169)
disciformis, Lucina 250 (740)
disjuncta, Conchocele 255

Thyasira 255 (780)
dissimilis, Macoma (1036)
divaricata, Acila 147

Crenella 171 (193)

Nucula 147

Nuculocardia 171 (193)
divisus, Solen

Tagelus (1113, 1114)
dolabriformis, Mactra (Mactromeris)

(1171)

Spisula 314, 315, 317 (1171)
dombeii, Venus 276
dombeyi, Venus 276
Donacidae 302 (1082-1086)
domaciformia, Semeloidea 238
Donacilla 288
donacina, Psammotaea 288

Tellina 288
Donax 302, 303

californicus 302-303

flexuosus 302

gouldii 267 (887)

gracilis 303 (1089)

irus 279, 282 (956)

obesus 303

rugosa 302

striata 302

stultorum 266, 267

triangulata 238
Donax (Notodonax) anna-eugeniae

(1087)
Donax (Serrula) gouldii 303 pl. 48, 57
donmilleri, Chlamys (Swiftopecten) 207
(437)
dorsalis, Teredo (1322)

Xylophaga (1322)
dosin, Chama 264, 265
Dosinia 264-265 (876)

arnoldi 266

jacalitosana (879)

longula 270

merriami 266

ponderosa 265 (877,878)

ponderosa jacalitosana 265
Dosinia (Dosinia) concentrica 265

ponderosa diegoana 143, 265-266

pl. 47, 49, 51

(Dosinia) concentrica, Dosinia 265

ponderosa diegoana, Dosinia 143,

265-266 pl. 47, 49, 51

Dosinidia 265

dregeri, Pecten 172

dukei, Eodonax (1088)

dunkeri, Artemis 267

Mytilus 163
duplex, Pecten (Flabellipecten) 185

(305)

Pecten (Patinopecten) (305)
durhami, Chlamys 192 (343)
dysera, Chione 272

Venus 272
Dysodontida 161

E
eborea, Ledina 149
senescens, Chlamys 202 (397)
sensecens, Pecten (397)
senescens walkerensis, Chlamys 202
(398)
walkerensis, Chlamys (398)
Ecphora (1343)
ecudoriana, Basterotia (Basterotella)
242 (684)
Crenella 171 (195)
Macoma (Macoploma) 295
santiaga, Crenella 171 (196)
edentula, Gari (Psammocola) 305

393

Lucina 242
Psammobia 305
Psammobia aff. 305 (1108)
Siliquaria 305
edentulus, Gobraeus 304 pl. 48
edule, Cardium (823, 834)
edulis, Mytilus 162-163 (140, 141)
Ostrea 215, 216
eldridgei, Aequipecten circularis (377)
Chlamys (Argopecten) 198 (377)
Pecten (Plagioctenium) (377)
elegans, Cumingia 302
elimata, Macoma (Macoma) 290, 291-292
pl. 53
elliptica, Crenella 170
Sphaenia 319 (1209)
ellisi, Chlamys (Chlamys) hastata 143,
188, 190-191 pl. 31, 34
elongata, Anadara (Anadara) amicula (96)
Spisula 317
elongatus, Protodonax (1088)
elsmerensis, Chione 275 (938)
englishi, Tellina 286 (1001)
Ennucula 144, 145 (25, 26)
(Ennucula) balboana, Nucula 143, 145-
146 pl. 27
bellotii, Nucula (30)
quirica, Nucula (28)
ensifera, Securella 274
Ensis 307, 309 (1137, 1138)
californicus 309, 310 (1139)
magnus 309
myrae 309-310 pl. 57
tropicalis 310 (1142)
ensis, Solen 309
entobapta, Venus 274
Eodonax (1088)
dukei (1088)
Eomiltha 250 (738)
ephippium, Anomia 223
Epilucina 243, 247
(Epilucina) californica, Lucina 247-248
pl. 46
equatorialis, Poromya (Dermatomya)
340 (1368)
ericellus, Chlamys (Argopecten) 196,
199 pl. 32
Pecten (Plagioctenium) 199
erici, Ostrea 216, 217-218 pl. 38
ernestsmithi, Stralopecten (430)
Erycinacea 234 (648)
Erycinidae 234 (645)
erythraeensis, Pecten 181
estrellana, Chlamys (Lyropecten) 205
Panope cf. 329
estrellanum, Pallium (461)
estrellanus catalinae, Chlamys (Lyropecten)
211
catalinae, Pecten (Lyropecten) (463)
Chlamys (Lyropecten) 210
Glycimeris 329 (1279)
Lyropecten (Pallium) 208
Pecten 208
Pecten (Lyropecten) 210 (461)
terminus, Chlamys (Lyropecten) 211
terminus, Pecten (Lyropecten) (462)
estrellatus cerrosensis, Lyropecten (s. s.)
210
etchegoini, Chlamys (Swiftopecten) 207
(431)
Chlamys (Swiftopecten) parmeleei
207

parmeleei, Chlamys 206

Pecten 207 (431)

Pecten (Pallium) swiftii (422)
Eucharis 241
Eudosmodontida 334 (1325)
euglypta, Chione 276 (948)

Protothaca (Novacallithaca) 277
Eumodiola 166

394

Eurhomalea 271 (915, 916)
Eutaxodontida 152
Euvola 174
(Euvola) cataractes, Pecten 181
evermanni, Chlamys (Argopecten) 200
exalbida, Venus (897)
excavata, Cytherea (704)
Lucina (Here) 244 pl. 46
Metis 298 (1063)
temblorensis, Lucina (Here) 244
(705)
Venus 274
excavatus, Pecten 177, 181 (263)
exigua, Nucula (Lamellinucula) 145,
146-147 pl. 27
Nucula (Nucula) 146
expansus, Mytilus mathewsonii (144)
Pecten (Patinopecten) 178, 183
exustus, Mytilus (151)

F
faba, Modiola (192)
Mytilus (192)
falcata brioniana, Spisula 314 (1170)
Mactra (Spisula) 314, 316
Spisula 314, 316, 137 (1169)
Spisula (Mactromeris) cf. S. (M.) 314
pl. 54, 57
Spisula (Symmorphomactra) 313
falorensis, Patinopecten (Lituyapecten)
185 (308, 309)
faujas, Panope 327
fausta, Semele 300
favus, Cyclopecten (482)
Felania usta 253
(Felania) rosea, Diplodonta 252
usta, Mysia 253
Felaniella 252, 253
(Felaniella) cornea, Diplodonta 253-254
pl. 43
sericatus, Taras 254
usta, Diplodonta 253
Felipes 205 (425)
pesfelis (425)
femii, Zirfaea gabbi 332 (1308)
fernandezensis, Arca 153
fernandoensis, Cardium quadrigenarium
260 (829)
Chione (Anomalocardia) 275, 276 (940)
feroensis, Psammobia (1102)
Psammobia (Tellina) (1102)
Tellina (1102)
ferruginosa, Montacuta (664)
fidenas, Anomia 224 (557)
filosa, Arcoperna (190)
Lucina 246
filosus, Phacoides (Lucinoma) 246
Fimbria 227 (588)
fisheri, Ostrea 221
fitchi, Penitella 333
flabellatus, Modiolus 167 (163)
Mytilus (Modiola) 163
flabelliformis, Flabellipecten 177
Ostrea 177
Pecten 177
Flabellipecten 173, 177-178, 185 (265,
268)
flabelliformis 177
floridus 178
(Flabellipecten) duplex, Pecten (305)
stearnsii, Pecten 178-180 pl. 29, 35,
text fig. 8
flabellum, Pecten (Chlamys) 196
flagleri, Macoma (Rexithaerus) indentata
296 (1045
flexuosa, Lucina 255, 256
Tellina 255, 256 (802)
Thyasira 255, 256 (802)
flexuosus, Cryptodon 255, 256

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Donax 302
florida, Janira 178
Ostrea 178 (269)
floridana, Basterotia (Basterotella) 241
Cochlodesma leana 338 (1343)
Pleurodesma 241
floridus, Pecten (269)
Flabellipecten 178
Pecten 178, 179
Florimetis 284 297-298
biangulata 298 pl. 53
cognata 298 (1061)
(Florimetis) intastriata, Apolymetis 297
fluctifraga, Chione 273
foliata, Placunanomia (582)
foliatus, Pododesmus 226 (582)
folium, Lopha (540)
fonesii, Solen 307
fontaineanus, Mytilus 168
formosa, Cyathodonta 324
Thracia (1357)
formosum, Nemocardium (Nemocardium)
262
fornicata, Modiola 167 (170, 171)
fornicatus, Modiolus (171)
forsteri, Leda (47)
Fortipectininae 182, 183 (291, 294)
fragilis, Arca 149
Sphaenia 321, 322
Tellina 293
Fragillidae 234 (646)
frankiana, Bornia (Temblornia) 143,
238-239
fraterculus, Pecten 178
frondosa, Chama 227
frons, Lopha (540)
fucata, Tellina 305 (1109)
Fugleria 152, 157
illota 158°
(Fugleria) illota, Barbatia 157-158 pl. 27
pseudoillota, Barbatia 157, 158 (108)
tenera, Barbatia 158
fumatus, Pecten 181

(e :
gabbi femii, Zirfaea 332 (1308)
Penitella 333
gabbiana, Poromya 341 (1363)
gabbii, Zirphaea 331
galapagana, Transennella 281-282
galapagensis, Pecten 181
galathaea, Lucinoma 246 (716)
Galaxura (1344)
galea, Strombus 321
gallegosi, Chlamys (Lryopecten) 211
Pecten (Lyropecten) (464)
gallica, Corbula 322
gallicana, Hiatella (1266)
Saxicava 325
gallina, Chione 272
gallus, Ostraea 221, 222
Gari 288, 304 (1095-1098, 1105-1107)
edentula 305
vulgaris 304
Gari (Psammocola) edentula 305
gari, Tellina (1095, 1102)
Garidae 303-304
gatunensis, Pecten 178 (266)
gealeyi, Chione (Chione) californiensis
273 (929)
Genaxinus 257 (803)
generosa, Panopaea 328
Panope 328-329 pl. 56
Panopea 328
solida, Panope 328 (1274)
gibba, Aloidis (Corbula) (1231)
Chlamys 198 (371, 372)
Corbula 323
Ostrea (371)

gibba-circularis, Chlamys 196, 198
gibberula, Gregariella 168
gibbiformis, Corbula (Corbula) 323
Corbula (Varicorbula) 323-324 pl. 57
gibbosus, Saxidomus 269, 270 (90S)
gibbus, Argopecten (365)
circularis, Pecten (Aequipecten) 199
Pecten 196 (371)
Solen 305, 306
Tagelus (1113)
gigantea, Hemimactra (116)
Hinnites 211
Lima 211, 212
Lucina (737)
Mactra (1166)
Ostrea 211
Panomya 329
Plagiostoma 211, 212
Venerupis (919)
Venus (894)
giganteus, Hinnites 211-212 pl. 41
Pecten (Hinnites) 211
Saxidomus 2710272 (919)
Gigantopecten 209 (450)
gigas laperousei, Ostrea 216
Ostrea 216
gilva, Cochlea 272 (926)
Glans 231-232
minuscula 232
subquadrata 232 pl. 43
trapezia 231, 232
(Glans) trapezia, Cardita 232
globosa, Panope 328 (1276)
globula, Sphenia cf. S. 321
Glycimeridae 158
glycimeris, Mya 327
Glycymeridae 158
Glycymerididae 158, 159 (117-119)
Glycymeris 158-159, 327, 328 (120-122,
586)
arctica 330 (1285)
barbarensis 161 (131)
coalingensis 159, 160
corteziana 160 (126)
estrellanus 329 (1279)
grewingki 159
keenae 161 (133)
migueliana 160 (127)
orbicularis 158
septentrionalis 160, 161
subobsoleta 159, 160, 161 (125)
tenuimbricata 161 (132)
vancouverensis 160 (128)
veatchii 161
Glycymeris (Axinola) grewingki 159-160,
161 pl. 27
profunda 159, 160-161 pl. 27
glycymeris, Arca 158
Chama 158
Glycymerula 159 (124)
Gobraeus 304
californicus 305
edentulus 305 pl. 48
variabilis 304
vespertinus 304
golischi, Mysella 240 (679)
Rochefortia 240 (678)
gorgoniis, Ostrea indici ($40)
gorokuense, Cardium (Trachycardium)
260 (832)
gouldi, Donax (887)
Gouldia pacifica (S96)
gouldiana, Cardiomya 342
Neara 342
gouldii, Axinus 256
Cryptodon 255
Donax (Serrula) 267, 303 pl. 48, 57
Lucina 255, 256
Thyasira 255-257 pl. 43 (793)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Thyasira cf. T. (798)
gracilis, Donax 303 (1089)
Grandipecten 209 (450)
grandis, Hemimactra (1166)
Mactra 317
granti, Corbula (Varicorbula) 324 (1236)
granulosa, Verticordia (1381)
grata, Protothaca 276 (949)
grayanus, Mytilus 163
Septifer 166 (160, 161)
Gregariella 162, 168, 169
chenui 168-169 pl.
coarctata 169
denticulata 169 (175, 176)
gibberula 168
opifex 169
sulcata 168
(Gregariella) chenui, Modiola 168
opifex, Modiolaria 169
gregoryi, Anguipecten (432)
grewingki, Glygymeris (Axinola) 159-160,
161 pl. 27
griesensis, Diplodonta 253
guineensis, Aloidis 322
Solen 305, 306
Gula soricis 166

H
haitensis, Ostrea 219, 221 (533, 534)
vespertina, Ostrea 220
hakei, Chlamys (Argopecten) 196, 197,
199-200 pl. 33
Pecten (Plagioctenium) 199
Haliotis 234, 332
tufescens 234
hamlini, Pecten (Chlamys) 205, 207
(416, 432)
hamillus, Anomia 224
hancocki, Pecten (Oppenheimopecten)
181, 182 (284)
hannibali, Lucina 249 (727)
Paphia (Protothaca) staminea 277
Phacoides (Lucinoma) (727)
harfordi, Diplodonta 254 (775)
Harlea 241
hartmanni, Pecten 180
hastata, Chlamys (Chlamys) 188-189,
190, 191 pl. 33
ellisi, Chlamys (Chlamys) 143, 188,
190-191 pl. 31, 34
hericius, Chlamys (Chlamys) 188,
189-190, 191 pl. 33
Mimachlamys 189
' pugetensis, Chlamys 191
hastatus hericius, Pecten (Chlamys) 190
hindsii, Pecten 195
hindsii, Pecten (Chlamys) 194
ingeniosa, Pecten (Chlamys) (322)
navarchus, Pecten 194
Pecten 188, 190, 212
Pecten (Chlamys) 188-189 (322)
Pecten (Pecten) 189
var. (?), Pecten (Pecten)
hawleyi, Pecten (Pecten) 178 (267)
haywardensis calvaerasensis, Pecten (Patin
opecten) 185 (299)
Pecten (Patinopecten) 185 (298)
healeyi, Pecten (Patinopecten) 172, 183-
185, 274 pl. 31, 33, 36, text fig. 9
(296)
heathiana, Isnochiton 240
heermanni, Ostrea 219, 220, 221 (522)
heimi, Pecten (Pecten) 180, 182 (281)
hemicyclus, Pecten 178
Hemimactra 313 (1166)
gigantea (1166)
grandis (1166)
(Hemimactra) mercedensis, Spisula 316
mossbeachensis, Spisula 315 (1175)
Hemimetis 297 (1057)

(Hemimetis) plicata, Apolymetis (1057)
hemphilli, Lima (Limeria) 215 (494)
Mactra 315
orcutti, Spisula (Mactromeris) 315
(1177)
Pecten (Janira) bellus 175
Pecten (Pecten) 175, 176, 177 (253)
Pecten (Pecten) bellus 175, 177 (254)
Spisula (Mactromeris) 315-316 pl. 54
57

Here 243
richthofeni 243
(Here) andersoni, Phacoides (700)
aragoensis, Lucina (697)
excavata, Lucina 244 pl. 46
excavata temblorensis, Lucina 244
(705)
richthofeni, Lucina 243, 244
richtohfeni, Lucina 243, 244
richthofeni, Phacoides 244
taffana, Lucina (697)
hericeus navarchus, Pecten 193
hericius, Chlamys (Chlamys) hastata 188
189-190, 191 pl. 33
Pecten 189-190
Pecten (Chlamys) 190
Pecten (Chlamys) hastatus 190
hermonvillensis, Venus (898)
heroicus, Lucina 249
hertleini, Basterotia (Basterotella) 241-
242 pl. 57
Chlamys 193
Pecten (Chlamys) 345
herviderana, Transennella 281
Heteroclidus 335-336
(Heteroclidus) hukusimana, Pandora
(1334)
punctata, Pandora 336 pl. 42
Heterodontida 228
Heterodonax bimaculatus 320
heteroglypta, Chlamys (Swiftopecten) 205
hians, Lima (493)
Hiatella 325-326 (1246)
arctica 326-327 pl. 56 (1266)
arctica bilineata 327 (1259)
biaperta 325, 326
gallicana (1266)
monoperta 325, 326
orientalis 327 (1260)
pholadis 326, 327 (1248)
sakhalinensis (1246)
solida 327 (1254)
vera 327
Hiatellacea 325
Hiatellidae 158, 325, 326
(1239-1243)
hillanum, Cardium 262
hindsi, Chlamys islandica 195 (355)
hindsii jordani, Pecten (Chlamys) (342)
Kincaidi, Pecten 192
kincaidi, Pecten (Chlamys) 192, 195
navarchus, Pecten (Chlamys) 194
Pecten (Chlamys) 193, 194, 195
Pecten (Clhamys) hastatus 194
Pecten hastatus 195
Pecten (Pecten) islandicus 194
Hinnita 211 (469)
Hinnites 172, 173, 189, 211
benedicti 212 (474)
cortesii 211
cortesyi 212
crassa 211, 212 (470, 472)
cf. H. crassa 212 (473)
crispa 212 (475)
gigantea 211
giganteus 211-212 pl. 41
leymerieri (468)
multirugosus 212 (476-480)
multirugosus crassiplicatus 212 (471)
poulsoni 211, 212

395

sinuosus 211
(Hinnites) giganteus, Pecten 211
Hippagus 170 (1382)
cardiiformis 343
novemcostatus 344
verticordius 343
hopkinsi, Pecten (Lyropecten) (445)
Hormomya 164 (151)
adamisiana 164
(Hormomya) adamsianus, Brachidontes
164
adamsianus, Mytilus 164
stearnsi, Mytilus 164
howelli, Ostrea 221
hua, Calloarca (Barbarca) (105)
hukusimana, Pandora (Heteroclidus)
(1334)
hyotis, Lopha (540)
Ostrea 220, 221
hyperborea, Yoldia 151

I
idae, Tellina cf. (997)
Tellina (Tellinella) 285-286 pl. 53
(997-999)
ignobilis, Venus 276
iizukai, Merretrix 270 (907)
Iliochione 273 (928)
Illesca 243 (700)
illota, Arca 157
Barbatia (Acar) 157
Barbatia (Fugleria) 157-158 pl. 27
Byssoarca 157
Fugleria 158
imanishii, Chlamys 195 (359)
imbrifer, Pecten 213
imitata, Chlamys (Argopecten) 202 (399)
impolita, Diplodonta 253 (770)
impostor, Aequipecten circularis (396)
Chlamys (Argopecten) 202 (394)
Pecten 198 (394)
inaequalis, Thyasira (789)
inaequivalvis, Periploma 336
Solen 334
Tellina 295, 334
incognita, Cryptomya 319
Mya (Cryptomya) (1211)
incubans, Cyclopecten 213
indentata flagleri, Macoma (Rexithaerus)
296 (1045)
Macoma 297 (1050)
Macoma (Rexithaerus) 296 pl 52
tenuirostris, Macoma aff. (1051)

Crenella 171 pl. 41
Cyclocardia 231 (624)
Lima (490, 493)
Limaria 215
Lutrana 318 (1193)
Ostrea (490)
Venericardia (Cyclocardia) (624)
inflatus, Modiolus 167, 168 (172)
Mytilus 171
ingeniosa, Chlamys (322)
Pecten (Chlamys) hastatus 189 (322)
tanakai, Chlamys 195 (360)
inheringiana, Miltha 251
inornata, Placunanomia 225
inquinata affinis, Macoma 293 (1034)
arnheimi, Macoma 293 (1033)
Macoma (1031, 1033)
Macoma (Macoma) 290, 292-293
pl. 52
Tellina 292
insignis, Thyasira (789)
insurana, Tellina (1003)

396

intastriata, Apolymetis (Florimetis) 297
intensa, Lucina (Parvilucina) tenuisculpta
248-249 pl. 46
Lucina tenuisculpta 249
intensus, Phacoides (Parvilucina) 248
intercalata, Martesia 333 (1310)
intermedia, Janira 174
intermedius, Chlamys (Nodipecten) sub-
nodosus 209
interrupta, Tellina 285
intrastriata, Tellina 297
invalida, Chlamys (Argopecten) 196, 199,
200-201 pl. 33
invalidus, Aequipecten circularis 200
Pecten (Plagioctenium) 200
ione, Placunanomia 225
Irona (958)
Ironus (958)
irradians, Aequipecten (210)
Pecten (210)
Irus 279 (956)
lamellifer prelamellifer (961)
irus, Donax 279, 282 (956)
Macoma 293
Tellina (1028)
Venerupis (956)
Irusella 264, 279
lamellifera 279 pl. SO
Ischnochiton 240
conspicuus 240
heathiana 240
magdalenensis 240
ishimoriensis, Macoma 294 (1040)
islandica, Chlamys 188, 191, 193
hindsi, Chlamys 195
Pecten 187
islandicus hindsii, Pecten (Pecten) 194
jordani, Chlamys (338)
jordani, Pecten (Pecten) cf. (337)
Pecten 191, 192
picoensis, Pecten (Chlamys) 195 (349)
pugetensis, Pecten 190, 191 (333)
pugetensis, Pecten (Chlamys) (333)
venturaensis, Pecten (Chlamys) 195
isocardia, Cardium (824)
Isodontida 171
izurensis, Macoma (Macoma) calcarea 292

J
jacalitosana, Dosinia (879)

Dosinia ponderosa 265

Macoma 293
jacobaeus, Pecten 174, 177
jamaicensis, Lucina 242
Janira 174

bella 174, 176

dentata 178, 181

florida 178, 179

intermedia 174
(Janira) bellus hemphilli, Pecten 175

bellus slevini, Pecten (260)

stearnsii stearnsii, Pecten 179

vogdesi, Pecten 181
japonica, Mya (1034)

Panopaea (1282)

Panope 329 (1282)
jeffersonianus, Pecten 209
jessoensis, Pecten (213)
joannis, Miltha 251

Phacoides 251 (745)
joaquinensis, Transennella 281
jonesii, Solen 307
jordani, Chlamys 194

Chlamys (Chlamys) 188, 191-192

pl. 30, 32
Chlamys (Chlamys) cf. C. (C.) 191,
192 pl. 32

Chlamys islandicus (338)

Chlamys rubida 192 (341)

Pecten (Chlamys) 191 (339)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Pecten (Chlamys) hindsii (342)
Pecten (Pecten) cf. islandicus (337)
josslingi, Pecten (Convexopecten) 180
Jouannetiinae 330
juanensis, Pecten (Pecten) 180, 182
Jupiteria 149 (45)
(Jupiteria) callimene, Leda (51)
juriana, Nuculana (46)

K
kagamianus, Pecten 182
kakumana, Thracia 339 (1354)
Kalayoldia 151
(Kalayoldia) cf. Y. (K.) cooperi, Yoldia
(61)
oregonensis, Yoldia (62)
kamagai, Mizuhopecten 172
kanakoffi, Chione (Securella) 143,
274-276 pl. 49, S1
Thracia 143, 338-339 pl. 42
kaneharai, Chlamys 190
Pecten (331)
Katherinella 268, 269 (892)
Katherinella (Katherinella) angustifrons
(901)
(Katherinella) angustifrons, Katherinella
(901)
keenae, Bornia (Temblornia) (672)
Glycymeris 161 (133)
Schizothaerus 318 (1198, 1199)
Keenaea 258, 262-263
(Keenaea) centifilosum, Nemocardium
263-264 pl. 46
keeni, Septifer 166 (159)
keittensis, Cumingia? 301
Kellia 235, 236-237, 238
laperousii 237 pl. 44
laperousii chironii 237 (670)
rotunda 237
suborbicularis 236, 237 (664)
Kelliidae 235 (653)
Kellya 236
laperousei 237
Kellyia 236
sebetia 238
kelseyi, Lithophaga plumula 170 (183)
Macoma (Macoma) nasuta 290, 294-
kelseyi, Lithophaga plumula 170 (183)
Macoma (Macoma) nasuta 290, 294-
295 pl. 52 text fig. 13
Milneria 234 (641)
Milneria cf. M. (639)
Kennerlia 335
(Kennerlia) arenosa, Pandora 335
bicarinata, Pandora 335
Kennerlyia 335
(Kennerlyia) pseudobilirata, Pandora
335 (1333)
kesenensis, Tellina 287 (1007)
kewi, Mytilus 163 (145)
kincaidi, Chlamys 195
Pecten (Chlamys) hindsii 192, 195
(340)
Pecten hindsii 192
kindlei, Chlamys (Swiftopecten) 20S, 208
Pecten (Chlamys) 207
Pecten (Manupecten) (436)
kipenensis, Papyridea (829)
kissyuensis, Schizothaerus nuttallii 318
(1200)
kobeltiana, Arca 154 (78)
Kotorapecten 182, 185
kovatschensis, Protothaca 277 (952)
Yoldia cooperi 152 (68)
krausei, Macoma (1017)
krusensterni, Solen 309
kurosawaensis, Patinopecten (Patinopecten)
poculum (311)
Pecten 187

L
(Labis) attenuata, Lithophaga (187)
attenuata rogersi, Lithophaga 170
(188)
lachiogramma, Tellina 286
laciniata, Protothaca 276
Tapes 277
laeta, Chlamys 172
laeve, Cardium 236
laevicardium 261 (835)
Laevicardium (Carastoderma) corbis
261
Laevicardium (Trachycardium) quadragen-
arium 259
laevigata, Corbula 322
laevis, Aligena 235, 235 (659)
lamarckii, Spondylus 321
lamellifer prelamellifer, rus (961)
Irusella 279 pl. SO
Venus 279 (956)
Lamellinucula 144, 146 (31)
(Lamellinucula) exigua, Nucula 146-147
pl. 27
lamellosa, Cumingia 301, 302 (1081)
Thyella 302 (1080)
lampe, Anomia 224
lanceolata, Tellina 288
laperousei, Kellya 237
Ostrea gigas 216
laperousii, Chironia 236, 237
chironii, Kellia 237 (670)
Kellia 237 pl. 44
lapicida, Petricola 282
Venus 282
laqueatus, Pecten (262)
larbas, Anomia 224
latiaurata, Chlamys (Leptopecten)
203-204 pl. 35
Chlamys (Leptopecten) cf. 204
(411)
delosi, Chlamys (Leptopecten) 203
latiauritus delosi, Pecten (Chlamys)
(404)
Pecten (Chlamys) 203, 204
laticaudata, Ostrea 217 (S10)
Ostrea lurida (S10)
latissima, Macrochlamis (450)
lattissimus, Pecten 209
latrinidadis, Barbatia (Acar) milifilia
158 (112)
latus, Saxidomus nuttalli 271, 272 pl. 50
lawsoni, Pecten (Chlamys) 189 (320)
Lazaria subquadrata 323
lazarus, Chama 227 (587)
leana, Anatina (1344)
Cochlodesma (1344)
floridana, Cochlodesma 338 (1343)
lechriogramma, Tellina (Maera) 286
lecontei, Pecten (Pecten) 177 (258)
Leda 148, 149
balboae (53)
caelata 150
coelata 150
commutata 149
forsteri (47)
leonina 149
pontonia (52)
taphria 150
Leda (Jupiteria) callimene (51)
Ledina 149
eborea 149
smirna 149
Leguminaria 310
Leionucula 145 (25, 26)
Lembulus 149 (44)
rossianus (44)
Lentidiinae 324
Lentidium 324
maculatum 324
mediterranea 324

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

(Lentidium) luteola, Corbula 324-325
pl. 55
leonina, Leda 149
Nuculana 149
Nuculana (Nuculana) aff. N. (N.)
149 pl. 57
leptogrammica, Arca (Arca) 154 (80)
Lepton (652)
Leptonacea 234-235 (642-651)
Leptonidae 234
Leptopecten 173, 202-203
(Leptopecten) bellilamellata, Chlamys
203 pl. 32
camerella, Aequipecten 204 (410)
cracens, Aequipecten 204 (412)
desultoria, Chlamys 203 (406)
latiaurata, Chlamys 203-204 pl. 35
cf. latiaurata, Chlamys 204 (411)
latiaurata delosi, Chlamys 203 (404)
monotimeris, Chlamys 203, 204
prevalidus, Pecten 203 (401)
Leptosolen 310
leymerieri, Hinnites (468)
liana, Lucina 245 (710)
Phacoides (Lucinisca) 710
ligamentina, Tellina 295
Lima 212, 214
alba 214
angulata (492, 495)
auana 215 (496)
gigantea 211, 212
hemphilli 215 (494)
hians (493)
inflata (490, 493)
orbignyi 215 (492, 495)
squamosa 214
Lima (Limaria) hemphilli (494)
orcutti 143, 215 pl. 35, 36, 57
lima, Byssoarca (103)
Ostrea 214
Limacea 214
Limaria 214
inflata 215
(Limaria) hemphilli, Lima (494)
orcutti, Lima 143, 215 pl. 35, 36, 57
limatula, Anomia 224
Limidae 214
lincolnensis, Molopophorus (892)
Linga 243 (698, 699)
linki, Pecten 203
lintea, Lucina 244
Lioconcha 268 (893)
(Lioconcha) newcombiana, Circe 268
Lionucula (25)
Lionucula (25)
Lithodomus 169
barbatus 168
dactylus 169
subula (185)
Lithophaga 162, 169-170 (179)
aristata 169
attenuata 170 (187)
mytuloides 169
plumula (186)
plumula kelseyi 170 (183)
sp. 170
Lithophaga (Diberus) subula 170
(184, 185)
Lithophaga (Labis) attenuata (187)
attenuata rogersi 170 (188)
lithophaga, Petricola 283
Venus 282, 283
Lithophagus communis 169
lithophagus, Mytilus 169
Lithotornus 169
Littorina (1027)
lituyaensis, Patinopecten (Lituyapecten)
186
Lituyapecten 173, 182, 186
(Lituyapecten) coosensis, Pecten 187

(314)
dilleri, Patinopecten 187
cf. P. (L.) dilleri, Patinopecten 187
dilleri, Pecten 186-187 pl. 35
falorensis, Patinopecten 185 (308, 309)

lituyaensis, Patinopecten 186

poulcreekensis, Patinopecten 186,
187 (310)

purisimaensis, Pecten 187 (312)

yakatagensis, Pecten 187

livida, Psammobia depressa 304

loeli, Ostrea 220, 221

lohri, Pecten (Patinopecten) 183, 185

(295, 296)

longa, Spisula 315 (1176)

longisinuata, Macoma calcarea (1024)

longisinuatus, Tagelus affinis 306

longula, Dosinia 270

Lopha 221 (540)
cornucopiae (540)
crista-galli (S40)
folium (540)
frons (540)
hyotis ($40)
plicatella (S40)
theca (540)

(Lopha) cumingiana, Ostrea 216
megodon, Ostrea 221
paramegodon, Ostrea (545)

lordi, Chione (963)
ovalis, Psephidia 280
Psephidia 280, 281 (963)
Psephis 280

lordii, Chione 280

lorenzana, Pholadidea (Pentiella)

333 (1315)

Loripes parilis (772)

loscombiana, Pholadidea (1309)

lubrica, Cadella 287

lucasana, Petricola (Petricola) 283

lucida, Siliqua 311 pl. 49

lucidus, Solecurtus 311

Lucina 242-243 (694-695)
acutilineata 247, 249 (721)
aequizonata 249
albella (734)
annulata desilirata 249 (725)
bella 245, 247
borealis (718)
californica 245, 247
childrinae 250, 251
columbella (698, 699)
contorta (738)
cornea 253
cribraria 244
disciformis 250 (740)
edentula 242
filosa 246
flexuosa 255, 256
fouldii 255
gigantea (737)
gouldii 255, 256
hannibali 249 (727)
heroicus 249
intensa 249
jamaicensis 242
liana 245 (710)
lintea 244
megameris 242 (692)
nassula 244
nitens 253
nuttalli centrifuga 245
orbella 252
pensylvanica 242
radians 247
sanctae-crucis (748)
sericata 254, 267
tellinoides (774)
tenuisculpta 248
tenuisculpta intensa 249

397

yokoyamai 245 (712)
Lucina (Epilucina) californica 247-248
pl. 46

Lucina (Here) aragoensis (697)
excavata 244 pl. 46
excavata temblorensis 244 (705)
richthofeni 243,244
taffana (697)

Lucina (Lucinisca) nuttalli 181, 245-

246 pl. 45
nuttalli antecedens 246 pl. 46

Lucina (Lucinoma) annulata 247 pl. 46
chiripanica 246 (717)

Lucina (Miltha) childreni 249
xantusi 250

Lucina (Myrtea) acutilineata 247
californica 247
nipponica 248 (732)
nuttallii 245 (711)
tenuisculpta 248

Lucina (Parvilucina) approximata 249

(736)
tenuisculpta 249
tenuisculpta intensa 248-249 pl. 46

Lucinacea 242 (689, 690)

Lucinidae 242, 252 (691, 693)

Lucinisca 243, 244-245
menuda (708)
nuttalli 245

(Lucinisca) liana, Phacoides (710)
nuttallii antecedens, Lucina 246 pl. 46
nuttallii centrifugus, Phacoides (709)
nuttalli, Lucina 245-246 pl. 45
cf. nuttallii, Phacoides 245

Lucinoma 243, 246-247 (713)
annulata densilirata (725)
annulata-Turcica caffea 157 (800)
borealis 246, 247 (718, 719)
galatheae 246 (716)
marwicki 246 (715)

(Lucinoma) annulata, Lucina 247 pl. 46
chiripanica, Lucina 246 (717)
filosus, Phacoides 246
hannibali, Phacoides (727)
taylori, Myrtea 246 (714)

lunaris, Pecten 180 (270)

lupinus, Diplodonta 252
Venus 252

lurida laticaudata, Ostrea 217 (510)
Ostrea 217, 219 (520)

luteola, Alodis (Caryocorbula) 324
Corbula (Caryocorbula) 324
Corbula (Lentidium) 324-325 pl. 25
rosea, Corbula 324

luticola, Bornia 237
Corbula 321, 322
Sphenia 321, 322
Sphenia cf. S$. 321-322 pl. 56

Lutraria capax 318 (1192)
inflata 318 (1193)
maxima 317, 318 (1190, 1191)
nuttalli 317, 318
? traskei 270 (904)

Lutricola cognata (1061)

lyallii, Acila 147

Lyonsia 329, 330

Lyropecten 173, 196, 205, 207, 210
crassicardo 208

Lyropecten (Lyropecten) estrellatus
cerrosensis 210

Lyropecten (Pallium) estrellanus 208

(Lyropecten) ashleyi, Pecten 210

cerrosensis, Chlamys 200, 209-211
pl. 34, 36

cerrosensis, Pecten 210

crassicardo, Chlamys 205, 211 (465)

dilleri, Pecten 186, 210

estrellana, Chlamys 205, 210

estrellanus catalinae, Chlamys 211

estrellanus catalinae, Pecten (463)

398

M

estrellanus, Pecten (461)

estrellanus terminus, Chlamys 211
(462)

estrellanus terminus, Pecten (462)

estrellatus cerrosensis, Lyropecten 210

gallegosi, Chlamys 211

gallegosi, Pecten (464)

hopkinsi, Pecten (445)

miguelensis submiguelensis, Chlamys

pretiosus, Pecten 209

macdonaldi, Pecten 178

Machaera 310

macloskeyi, Pecten 203

Macoma 284, 290 , 295, 297 (1016)

affinis plena 293 (1027)
anser 293 (1032)
aomoriensis 294 (1039)
balthica 293

calcarea 291, 292

calcarea longisinuata (1024)
calcarea obliqua (1024)
calcarea yokohamaensis 292 (1022)
copelandi 297

constricta (1060)
denticulata 295

dissimilis (1036)
ecuadoriana 295

identata (1050)

aff. identata tenuirostris (1051)
inquinata (1031, 1033)
inquinata affinis 293 (1034)
inquinata arnheimi 293 (1033)
irus 293

ishimoriensis 294 (1040)
jacalitosana 293

krausei (1017)

moesta 291 (1017)

moesta acolasta 291
moliniana 291 (1048)
morroensis 291

nasuta 296

secta 295, 296

tenera 290

tokyoensis 293 (1036)
twinensis 292

vanvlecki 296 (1046)

Macoma (Macoma) acolasta 290-291

pl. 53
calearea (1023)
calcarea izurensis 292
elimata 290, 291-292 pl. 53
inquinata 290, 292-293 pl. 52
nasuta 290, 293-294 pl. 53
nasuta kelseyi 290, 294-295 pl. 52,
text fig. 13

Macoma (Macoploma) ecudoriana 295

medioamericana 295 pl. 52

Macoma (Rexithaerus) identata 296,

297 pl. 52

identata flagleri 296 (1045)

identata tenuirostris 296, 297 pl. 41,
50, 52

(Macoma) acolasta, Macoma 290-291

pl. 53, 54
calcarea, Macoma (1023)
calcarea izurensis, Macoma 292
elimata, Macoma 290, 291-292 pl. 53
inquinata, Macoma 290, 292-293
pl. 52
nasuta, Macoma 290, 293-294 pl. 53,
54
nasuta kelseyi, Macoma 290, 294-295
pl. 52, text fig. 13

Macoploma 290, 295
(Macoploma) ecudoriana, Macoma 295

medioamericana, Macoma 295
medioamericana, Psammacoma 295

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

Macrocallista 268 (894)
Macrocallista (Megapitaria) aurantiaca
268
squalida 269
macrochisma, Anomia (575)
Monia 225 (576)
Placuanomia 225
Pododesmus (Monia) 225-226 pl. 40,
41
Macrochlamis 209 (450)
latissima (450)
Macrochlamys 209 (450)
macroschismus, Pododesmus (580)
Mactra 311, 312 (1159)
albaria 312-313
californica 316
catiliformis 315
constricta 297 (1060)
falcata 314, 316
gigantea (1166)
grandis 317
hemphilli 315
ovalis 313
planulata 314, 316
polynyma 313
revelei 315
sespeensis 298
solida 312
solidissima (1166)
squamosa (652)
thracioides 267
Mactra (Mactromeris) dolabriformis
(1171)
Mactra (Spisula) catilliformis 313
falcata 314
planulata 316
Mactracea 311 (1149, 1151-1157)
Mactridae 311 (1150)
mactroides, Dermatomya 340
Poromya (Dermatomya) 340
Mactromeris 311, 313
(Mactromeris) catilliformis, Spisula 312,
313-314, 316 pl. 54
dolabriformis, Mactra (1171)
cf. S. (M.) falcata, Spisula 314 pl. 54,
$7
hemphilli orcutti, Spisula 315 (1177)
hemphillii, Spisula 315-316 pl. 54
mercedensis, Spisula 312, 316 pl. 54
planulata, Spisula 312
cf. S. (M.) planulata, Spisula 316-317
pl. 57
Mactrotoma 313
revellei (1182)
maculatum, Lentidum 324
maculosa, Arca 154
madisonius, Pecten 209
Maera salmonea 286
(Maera) lechriogramma, Tellina 286
magdalenensis, Ischnochiton 240
magna, Cryptomya californica 319,
320-321 pl. 54, 55
magnificus, Pecten 209
magnolia, Pecten 309
magnus, Ensis 409
Solen 309
makumurai annakensis, Cardita (Mio-
dontiscus) 234
mandibula, Mya 327
Mantellum 214
Manupecten 191, 205, 206 (424)
pesfelis (424)
(Manupecten) kindlei, Pecten (436)
Maoritellina 285 (994)
Marcia 269 (897)
angustifrons 270 (903)
oregonensis 270
subdiaphana 269-270
Marcia (Mercimonia) angustifrons (901)
angustifrons brevilineata (902)

margaritacea, Corbula 322, 336
margaritana, Chione 275 (933, 935)
Septifer 166 (162)
margaritifera, Avicula (558)
mariae, Chione 276
Venus (945)
marionensis, Cryptodon 256 (795)
Martesia 330
intercalata 333 (1310)
Martesiinae 330
martini rostrata, Arca 148
martinicensis, Crassinella 228
marwicki, Lucinoma 246 (715)
Masudai Masudapecten 182
Patinopecten (Masudapecten) (290)
Masudapecten 182 (290)
masudae 182
(Masudapecten) masudae, Patinopecten
mathewsonii expansus, Mytilus (144)
Mytilus 163 (143)
maxima, Lutraria 317, 318 (1190, 1191)
Ostrea 174
maximus, Pecten 174 (250)
Tresus 317
medialis, Arcopagia 298
medioamericana, Macoma (Macoploma)
295 pl. 52
Psammacoma (Macoploma) 295
mediterrancea, Corbula 324
mediterranea, Corbulomya 324
Lentidium 324
Tellina 324
meekianum, Cardium (843)
Cardium aff. C. 261 (833)
Cerastoderma (843)
Clinocardium 261
myrae, Clinocardium 261 (844)
megameris, Lucina 242
Phacoides (692)
Megapitaria 264, 268
aurantiaca 269
squalida 268-269, 274 pl. SO
(Megapitaria) aurantiaca, Macrocallista
268

squalida, Macrocallista 269
squalidus, Pitar 268

megodon cerrosensis, Ostrea 222 (544)
Ostrea 216, 221 (540, 546, 547, 549)
Ostrea (Agerostrea) 221-222 pl. 38
Ostrea (Alectryonia) 221
Ostrea (Lopha) 221

melii, Pecten 209

menuda, Lucinisca (708)

Mera modesta 287

mercedensis, Spisula (Hemimactra) 316
Spisula (Mactromeris) 312, 316 pl. 54

(Mercimonia) angustifrons, Marcia (901)

angustifrons brevilineata, Marcia (902)

meridionalis, Pecten (211)
Merretrix iizukai 270 (907)
merriami, Dosinia 266
Pecten (?Patinopecten) 185-186
Pecten (Pecten) 185
Mesopeplum 205, 206, 209 (427, 428)
caroli (427)
Mesopleura 306
Mesosaccella 149 (47)
messor caimita, Ostrea 222
colombiensis, Ostrea 222
Ostrea 222 (548)
tabiquita, Ostrea 222
Metis 297 (1054)
alta 298 (1064)
excavata 298 (1063)
rostellata 298
vancouverensis 298
mexicana, Crassinella 229 (597)
Crassinella cf. C. 228
(Mexicardia) panamense, Trachycardium

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

260
procerum, Cardium 260
procerum, Trachycardium 260
meyeri, Tellina 297 (1054-1056)
microdonta, Anadara (Anadara?) 156
89, 90)
Arca 154, 155 (87)
migueliana, Glycymeris 160 (127)
miguelensis submiguelensis, Chlamys
(Lyropecten) 209
millifilia, Arca (Acar) 158 (111)
latrinidadis, Barbatia (Acar) 158 (112)
Milneria 229, 234 (639)
kelseyi 234 (641)
cf. M. kelseyi (639)
minima 234 pl. 43
Miltha 242, 243, 249-251 (741,742)
inheringiana 251 (750)
joannis 251
neozealanica 251 (751) (752)
neozelanica 251 (749)
cf. M. xantusi (744)
Miltha (Miltha) childrenae 249
xantusi 250-251 pl. 45
(Miltha) childrenae, Miltha 249, 251
childreni, Lucina 249
childreni, Phacoides 250, 251
sanctaecrucis, Phacoides 250, 251
(743, 746)
xantusi, Lucina 250
xantusi, Miltha 250-251 pl. 45
xantusi, Phacoides 250
Milthoidea 251 (752)
Mimachlamys hastata 189
minima, Ceropsis 234
Milneria 234 pl. 43
minuscula, Glans 232
minutus, Solen 325, 326
Miodon prolongatus 232, 233
scalaris 229
Miodontiscus 229, 232-233
prolongatus 233-234 pl. 56
(Miodontiscus) nakamurai annakensis,
Cardita 234 (638)
prolongata, Cardita 233 (636)
prolongata, Venericardia 233
mirabilis, Acila 147
mirifica, Nucula 145
miyatokoensis, Chlamys 190 (329)
Pecten (Chlamys) (329)
Mizuhopecten 182, 183
kamagai 172
modesta, Axinaea (124)
Mera 287
Tellina (Oudardia) 287-288
modestum, Cardium 262
centifilosum, Cardium 263
modestus, Angulus 287
Modiola 166, 168
attenuata (187)
faba (192)
fornicata 167 (170, 171)
opifex 168 (174)
petagnae 168
recta 166
sulcata 168
Modiola (Gregariella) chenui 168
(Modiola) chenui, Mytilus 168
flabellatus, Mytilus (163)
Modiolaria denticulata (175)
sulcata 168
Modiolaria (Gregariella) opifex 169
Modiolus 162, 166, 169, 170
carpenteri 167 (170)
directus 167 (164-169)
flabellatus 167 (163)
fornicatus (171)
inflatus 167, 168 (172)
opifex 168, 169
papauna 166

rectus 166-167 pl. 42
sacculifer 167-168 pl. 41
sulcatus 168
trinominatus 167 (173)
Modiolus (Brachydontes) playasensis (152)
modiolus, Mytilus 166
Moera 288
Moerella 284, 286, 288
(Moerella) arenica, Tellina 289 (1012)
carpenteri, Tellina 288-289 pl. 53, 56
salmonea, Tellina 286
moesta acolasta, Macoma 291
Macoma 291 (1017)
Tellina (1017)
moliniana, Macoma 296 (1048)
Molopophorus lincolnensis (892)
Monia 225
macrochisma 225 (576)
(Monia) macrochisma, Pododesmus 225-
226 pL 40, 41
monilicosta, Cardita 230
Cyclocardia 231 (614)
ochotica, Cardita 231 (619)
Venericardia 230
Monoeciostrea 216
monoperta, Hiatella 325, 326
monotimeris, Chlamys (Leptopecten)
202, 203, 204
Pecten 202
Montacuta ferruginosa (664)
substriata (664)
Montacutidae 239 (673)
montereyana, Anadara (Anadara) 156
(93)
Arca (93)
montereyensis, Cardita (Cyclocardia)
ventricosa (621)
Cyclocardia ventricosa 231 (621)
montesanoana, Anadara devincta 156
Arca devincta (94)
moorei, Nucula (24)
morani, Chlamys 208
Pecten (Chlamys) wattsi 207 (435)
morroensis, Macoma 291
mossbeachensis, Spisula (Hemimactra)
315
multicostata, Venerupis 279 (962)
multiformis, Mytilus 164, 165 (154)
multirugosus crassiplicatus, Hinnites 212
crassiplicatus, Pecten (Chlamys) (471)
Hinnites 212 (476-480)
Pecten (Chlamys) 211, 212
Pecten (Pecten) 212
Murex regius (177)
Musculus 168, 170
mutica, Cumingia 301
Mya 319 (1205, 1206)
abrupta 329 (1277)
arenaria 319
arctica 325, 326
crispata 331
glycimeris 327
japonica (1034)
mandibula 327
norvegica 329, 330
pernula 148
praetenuis (1344)
pubescens 338 (1351)
suborbicularis 236
Mya (Antiguamya) arnoldi (1204)
Mya (Cryptoma) californica 320
incognita (1211)
(Mya) norvegica, Panopea 329
Myacea 319
myalis, Nucula 151
Myidae 319 (1201)
Myochlamys 187
Myoparo 170
myrae, Clinocardium meekianum 261
(844)

399

Ensis 309-310 pl. 57
Myrmecia 317
Myrtea (Lucinoma) taylori 246
(Myrtea) acutilineata, Lucina 247
californica, Lucina 247
nipponica, Lucina 248 (732)
nuttallii, Lucina 245 (711)
tenuisculpta, Lucina 248
Mysella 239
anomala 239
golischi 240 (679)
pedroana 240 (677, 679)
tumida 239-240 pl. 44, 45
cf. M. tumens 240
Mysia (Felania) usta 253
Mytilacea 161
Mytilidae 161 (136-138)
Mytiloconcha 163
(Mytiloconcha) coalingensis, Mytilus
163
cf. M. (M.) coalingensis, Mytilus (148)
Mytilus 162, 169
adamsianus 164 (153)
bifurcatus 165
bilocularis 165
chenui 169
coalingensis 163
coalingensis n. var.? 164
cristagalli (S40)
decussatus 170
dunkeri 163
edulis 162-163 (140, 141)
exustus (151)
faba (192)
fontaineanus 168
grayanus 163
inflatus 171
kewi 163 (145)
lithophagus 169
mathewsonii 163 (143)
mathewsonii expansus (144)
modiolus 166
multiformis 164, 165
pholadis (1248)
schencki 163 (146)
sp. 163
stearnsi 164, 165
trampasensis 163
Mytilus (Crenomytilus) coalingensis
sternbergi 143, 163-164 pl. 41
Mytilus (Hormomya) adamsianus 164
stearnsi 164
Mytilus (Modiola) chenui 168
flabellatus (163)
Mytilus (Mytiloconcha) coalingensis 163
cf. M. (M.) coalingensis (148)
mytuloides, Lithophaga 169

N
nakamurai annakensis, Cardita (Mio-
contiscus) (638)
nakatombetsuensis, Patinopecten (Patino-
pecten) 187 (315)
Nanochlamys 205 (421)
notoensis 205
nassula, Lucina 244
nasuta kelseyi, Macoma (Macoma) 290,
294-295 pl. 52, text fig. 13
Macoma (Macoma) 290, 293-294 pl.
53, 54
Tellina 293
natoriensis, Pecten 205 (418)
subovalis, Pecten 205
navarchus, Pecten (Chlamys) hindsii 194
Pecten hastatus 194
Pecten hericeus 193
Navea newcombii 332
subglobosa 332
Navicula 152-153
naviformis, Cardita 232 (627)

400

Neaera 341 (1372)
chinensis 341
cuspidata 342
gouldiana 342
pectinata 342
neahensis, Chlamys (Argopecten) 196
Pecten (Plagioctenium) 198 (367)
neglecta, Venus 274
Nemocardium 258, 259, 262, 263 (849)
centifilosum richardsoni 264
samarangae 262
Nemocardium (Keenaea) centifilosum
263-264 pl. 46
Nemocardium (Nemocardium) formosum
262
(Nemocardium) formosum, Nemocardium
262

neozealanica, Miltha 251 (751, 752)
Neptunea tabulata, Thyasira gouldii-257
nevadanus, Pecten 183, 209
nevadensis, Tellina 286 (996)
newcombei, Cytherea (895)
Pododesmus 226 (581)
newcombiana, Callista 268
Circe (Lioconcha) 268
Pitaria 268
newcombianus, Pitar 268
newcombi, Pecten 195
newcombii, Navea 332
ninohensis, Patinopecten yamasakii
185 (304)
Nioche 273
Nioche (Nioche) asperrina asperrina (930)
(Nioche) asperrina asperrina, Nioche
(930)
asperrima, Chione 273
nipponensis, Chlamys 172
nipponica, Lucina (Myrtea) 248
Panomya 330 (1298)
Nipponopecten 182
nisataiensis, Chlamys 192 (344)
nitens, Lucina 253
nitida, Nucula 145
Tellina (Peronidia) 289 (1013)
nitidus, Spaniodon (654)
noae, Arca 152, 153, 154, 157
nobilis, Arca 156
noblei, Saxidomus (?) 271 (911)
Nodipecten 205, 209 (452)
(Nodipecten) arnoldi, Chlamys 172
condylomatus, Pecten 209
nodosa, Chalmys 205
nodulifera, Chlamys 205
subnodosa, Chlamys 205
subnodosus intermedius, Chlamys 209
(456)
nodosa, Chlamys (Nodipecten) 205
nodosiformis, Pecten 209
nodosus, Pecten 169, 209
nodulifera, Chlamys (Nodipecten) 205
Noetia 153
nomurai, Clinocardium (847)
Saxidomus 272 (923)
normalis, Psammobia depressa 304
norvegica, Mya 329, 330
Panomya 329
Panopaea 330
Panopea (Mya) 329
notata, Siliquaria 305
Notirus 279 (958)
Notochlamys 206 (428)
Notocorbula 323 (1229, 1230)
vicaria (1229)
Notodonax 302 (1087)
(Notodonax) anna-eugeniae, Donax
(1087)
notoensis, Nanochlamys 205
Pecten 205
Notovola 177 (264)
(Notovola) sp., Pecten (242)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

(Novacallithaca) euglypta, Protothaca 277

Novathaca 276 (948)
novemcostata, Verticordia 344
novemcostatus, Hippagus 344
nuciformis, Aloidis (Carycorbula)
(1235)
Corbula 324 (1235)
nucleus, Arca 144
Nucula 144, 145, 146, 147
albensis (25)
arctica 151
bellotii 146 (29)
caelata 150
cahuitensis 147 (34)
castor 145
castrensis 147
coelata 150
commutata 149
compressa 145
concava 149
divaricata 147
exigua 145
mirifica 145
moorei (24)
myalis 151
nitida 145
obliqua 145
paytensis 147 (33)
pontonia 151 (52)
quirica 145, 146 (27)
rugosa 146
suprastriata 146-147 (32)
tamatavica 146
tenuis 146
turgida (24)
venezuelana 147 (35)
vieta 147
Nucula (Acila) castrensis 148
Nucula (Ennucula) balboana 143, 145-
146 pl. 27
bellotii (30)
quirica (28)
Nucula (Lamellinucula) exigua 146-147
pl. 27
Nucula (Nucula) exigua 146-147
suprastriata (32)
(Nucula) exigua, Nucula 146-147
suprastriata, Nucula (32)
Nuculacea 144
Nuculana 148, 149, 151
balboae 151 (53)
juriana (46)
leonia 149
pernula 149
pontonia 151 ($2)
taphria 150
Nuculana (Nuculana) aff. N. (N.) leonina
149 pl. 57
Nuculana (Saccella) callimene 151 (51)
taphria 150-151 pl. 27 (55-58)
Nuculanicae 148
Nuculanidae 148 (42)
Nuculidae 144
Nuculocardia 170
divaricata 171 (193)
Nuculoma 145
nuda, Aligena aequata 236 (658)
nuttalli antecedens, Lucina (Lucinisca)
246 pl. 46
antecedens, Phacoides 246
Cardium 261
centrifuga, Lucina 245
giganteus, Saxidomus 271-272
kissyuensis, Schizothaerus 318 (1200)
latus, Saxidomus 271, 272 pl. 50
Lucina (Lucinisca) 181, 245-246
pl. 45
Lucina (Myrtea) 245
Lutraria 317
Saxidomus 271-272

Schizothaerus (1198)
Tresus (1195, 1196)
Venus 274, 277
nuttallii bighopensis, Schizothaerus
(1197)
Cardium 260
centrifugus, Phacoides (Lucinisca)
(709)
Clinocardium 261-262
Clinocardium aff. C. (838)
Lucina (Myrtea) (711)
Lutraria 318
Phacoides 245
Phacoides (Lucinisca) cf. 245
Schizothaerus 317, 318 (1198)
Tresus 318 pl. 54, 55
nutteri, Chlamys (Swiftopecten) 208
Pecten (Chlamys) 205, 207 (433)

oO
oahua, Barbatia (Abarbatia) (104)
obesa, Tellina 298
obesus, Donax 303
obliqua, Clementia 270 (096)
Macoma calcarea (1024)
Nucula 145
Tellina (1024)
oblonga, Pristiphora 240
Serridens 240
oblongum, Cardium (835)
oblongus, Pristes 240-241 pl. 44
obsoletus, Septifer bifurcatus 166 (156)
occidentalis, Cardita 230
Cardita aff. C. 231 (612)
Cyclocardia 230-231 pl. 43
ochlockoneensis, Pecten 178
violae, Pecten 178, 180 (274)
ochotensis, Yoldia cooperi 152 (65, 67)
ochotica, Cardita monilicosta 231 (619)
ochroleuca, Petricola 293
ocoyana, Turritella (920)
odontata, Chlamys 189 (327)
Odontogena 236
(Odontogena) borealis, Aligena 236 (661)
oldroydi, Cuspidaria (Cardiomya) 343
(1375)
Olivella biplicata 267
sayana 267
ooides, Tellina (1143)
opaca, Tapes (913)
opacus, Saxidomus (914)
Venus 271 (913)
opifex, Botulina 169
Gregariella 169
Modiola 168, 169 (174)
Modiolaria (Gregariella) 169
Modiolus 168
opima, Venus (897)
Oppenheimopecten 173, 180-181
(Oppenheimopecten) hancocki, Pecten
182 (284)
subbenedictus, Pecten 180
vogdesi, Pecten 181-182 pl. 29
opuntia, Chlamys (Chlamys) 188, 192-
193 pl. 30
Pecten (Chlamys) 192, 193
orbella, Diplodonta (Diplodonta) 252-
253 pl. 55, 57
Diplodonta cf. 253 (767)
Lucina 252
Tapes staminea 277
orbellus, Taras 252
orbicularis, Astarte 232, 233
Glycymeris 158
orbiculata, Axinopsis 257
orbignyi, Lima 215 (492, 495)
orcutti, Lima (Limaria) 143, 215 pl. 35,
36, 57
Spisula (Mactromeris) hemphilli 315
(1177)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

oregonensis cancellosus, Patinopecten
(300)
Cryptomya (1213, 1214)
Cytherea 270
Marcia 270
Pecten 182, 185 (300, 307)
Poromya 341
Yoldia (Kalayoldia) 152 (62)
orientalis, Hiatella 327 (1260)
Saxicava (1260)
ornata, Trigonulina 343, 344
Verticordia (Trigonulina) 344 pl. 43
Ostracites 216
Ostrea 172, 215-216

angelica 216, 217-218, 220 pl. 38

borealis 218

caboblancoensis 217 (511)

carinata 221 (542)

cerrosensis 220, 221, 222

cochlear 216 (S02)

conchaphila 219 (519)

?conchaphila palmula (517)

crispa 211

crista-galli 221 (540)

cumingiana 216 (513)

edulis 215, 216

erici 216, 217-218 pl. 38

fisheri 221

florida 178 (269)

gallus 221, 222

gibba (371)

gigantea 211

gigas 216

gigas laperousei 216

haitensis 219, 221 (533, 534)

haitensis vespertina 220

heermanni 219, 220, 221 (522)

howelli 221

hyotis 220, 221

indici gorgoniis (540)

inflata (490)

islandica 187

laticaudata ($10)

lima 214

loeli 220, 221

lurida 217, 219 (520)

lurida laticaudata 217 (S10)

maxima 174

megodon 216, 221 (540, 546, 547,
549)

megodon cerrosensis 222 (544)

messor 222 (548)

messor caimita 222

messor colombiensis 222

messor tabiquita 222

palmula 217, 219 (517)

paramegodon 222 (545)

sculpturata 219 ($23)

tayloriana 217

thomasi 221

titan 216

tuberculata 215

ungulata 221

veatchii 216, 219-221 pl. 39, 40

vespertina 216, 217, 218-219, 220
221 pl. 39 (526)

cf. vespertina 219 (528)

vespertina sequens 219 (518)

vespertina veatchii (512)

vespertina venezuelana 219 (525)

virginica 216 (505)

virleti 221 (526, 535-536)

wiedeyi 219, 220, 221 (531)

Ostrea (Agerostrea) megodon 221-222

pl. 38

Ostrea (Alectryonia?) caboblancoensis
(S11)

megodon 221

vespertina venezuelana (525)

Ostrea (Lopha) cumingiana 216

megodon 221
paramegodon (545)
Ostreacea 215 (497)
Ostreidae 215 (498-501)
Ostreum 216
otteri, Tibialectus 168
otutumiensis, Pecten (Swiftopecten)
207
oudardi, Tellina 287
Oudardia 284, 287 (993)
(Oudardia) buttoni, Tellina 289
modesta, Tellina 287-288
ovalis, Mactra 313
Psephidia 280 pl. 47, 51
Psephidia lordi 280
Spisula 313
Standella 313
ovata, Axinopsis 258
ovoidea, Chaceia 333
oweni, Pecten 183 (283)
Pecten (Blanckenhornia) (292)
owenii, Pecten (Patinopecten) (295)

P

Pachydesma 266

(Pachydesma) stultomum, Tivela

266-267 pl. 50

Pachyodontida 226

pacifica, Arca 153
Crassinella 229 (596)
Gouldia (596)

Miltha 251 (749)
pacificensis, Sphenia 322 (1218)
pacilus, Anomia 224
pajaroana, Venus (1189)

Tresus 318 (1189)
Palaeotaxodontida 144
Pallium albicans (262)

crassicardo (465)

estrellanum (461)

(Pallium) estrellanus, Lyropecten 208
swiftii etchegoini, Pecten (422)
swiftii parmeleei, Pecten 206

palmula, Ostrea 217, 219 (517)
Ostrea ?conchaphila ($17)

panamense, Trachycardium (Mexicardia)

260
Pandora 334-335
Pandora (Heteroclidus) hukusimana
(1334)
punctata 336 pl. 42
Pandora (Kennerlia) arenosa 335
bicarinata 335

Pandora (Kennerlyia) pseudobilirata 335

(1333)

Pandora (Pandorella) bilirata 335 pl. 47,
48

(Pandora) arenosa, Pandorella 335
Pandoracea 334
Pandorella 335
Pandorella (Pandora) arenosa 335
(Pandorella) bilirata, Pandora 335
pl. 47, 48
Panoridae 334 (1327)
Panomya 325, 329, 330 (1284)
ampla 330 (1286)
ampla chrysis 330 (1292)
arctica 329, 330
arctica turgida 330
beringiana 329, 330 (1301)
cf. P. beringiana 329-330 pl. 56
(1300)
gigantea 329
nipponica 330 (1298)
norvegica 329
Panopaea 327, 329
arctica 329
generosa 328
japonica (1282)
norvegica 330

401

spengleri 329

Panopaeidae 328
Panope 158, 325, 326, 327-328

aldrovanci 327
brockworthensis 327

cf. estrellana 329 (1281)
faujas 327

generosa 328-329 pl. 56
generosa solida 328 (1274)
globosa 328 (1276)
japonica 329 (1282)
similaris 329

ramonensis 329 (1281)
taeniata 329

tenuis 329
Panope (Panope) abrupta 328, 329 (1278)
generosa 328
(Panope) abrupta, Panope 328, 329
(1278)
generosa, Panope 328
Panopea generosa 328
solida (1272)
Panopea (Mya) norvegica 329
panzana, Chione 275 (934)
papauna, Modiolus 166
Paphia restorationensis (955)
cf. staleyi (944)
staminea 276
tenerrima 277
Paphia (Callithaca) tennerima alta 278
Paphia (Protothaca) staminea hannibali
277
Paphonotia 279 (959)
Papyridea kipenensis (829)
parafragile, Promantellum (491)
Paraglans 232 (628)
paramegodon, Ostrea (Lopha) 222
(S45)
Parapholas 330
parilis, Diplodonta 254
Loripes (772)
Taras (772)
parmeleei, Chlamys etchegoini 206
Chlamys (Swiftopecten) 206-208
pl. 31, 37, text fig. 10
etchegoini, Chlamys (Swiftopecten)
207
Pecten (Chlamys) 206
Pecten (Pallium) swiftii 206
Pecten (Swiftopecten) 206
parva, Penitella 332
Parvilucina 243, 248
(Parvilucina) approximata, Lucina 249
approximata, Phacoides (736)
intensus, Phacoides 248
tenuisculpta intensa, Lucina 248-249
pl. 46
tenuisculpta, Lucina 249
patelliformis, Placunanomia 225
Patinopecten 172, 173, 182-183, 186, 191
(289, 291)
coosensis (314)
dilleri 186
healeyi 184
masudai (290)
oregonensis cancellosus (300)
propatulus (297)
sp. (288)
cf. stearnsii 180 (276)
yamasakii ninohensis 185 (304)
Patinopecten (Lituyapecten) dilleri 187
cf. P. (L.) dilleri 187
falorensis 185 (308)
lituyaensis 186
Pationpecten (Masudapecten) masudai
(290)
Patinopecten (Patinopecten) poculum
kurosawaensis (311)
yamasakii yamasakii (302)
(Patinopecten) caurinus, Pecten 172

402

coosensis, Pecten (314)

dilleri, Pecten 186

duplex, Pecten (305)

expansus, Pecten 183

hay wardensis calaverasensis, Pecten
(299)

hay wardensis, Pecten (298)

healeyi, Pecten 183-185 pl. 31, 33,
36, text fig. 9

lohri, Pecten (295)

merriami, Pecten 185-186

nakatombetsuensis, Patinopecten
(315)

owenii, Pecten (295)

poculum kurosawaensis, Patinopecten
(315)

propatulus, Pecten 182, 186 (297)

purisimaensis, Pecten (312)

yakatagensis, Pecten (306)

yamasakii yamasakii, Patinopecten
(302)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

excavatus 177, 181 (263)
expansus 178, 183
flabelliformis 177

floridus 178 (269)
fraterculus 178

fumatus 181

galapagensis 181

gatunensis 178 (266)
gibbus 196 (371)

hancocki 181

hartmanni 180

hastatus 188, 190, 212
hastatus hindsii 195
hastatus navarchus 194
hawleyi 178 (267)

hay wardensis 185 (298)
hay wardensis calaverasensis 185 (299)
healeyi 172, 183, 274 (296)
heimi 180

hemicyclus 178

hemphilli 175, 176, 177 (253)

sanctaecruzensis 174
sardo 209

sericeus 178, 180 (271)
simpsoni 209 (458)
slevini 177

solidulus 195, 196
soror 178, 180 (277)
soror codercola 178, 180 (278)
squamatus 212

stearnsii 176, 178, 179, 181
subbenedictus 180
subnodosus (456)
swiftii 204

takahashii (294)

tigris 206 (426)
transenna 213

tryblium 185, (95, 301)
tumidus 197

tunica 203
valentinensis 174 (249)
vanvlecki 209

patula, Siliqua 311 (1148)
paytensis, Nucula 147 (33)
Pecten 172, 173, 174, 177, 178, 182, 187

hericius 189-190
hericeus navarchus 193
hindsii kincaidi 192

veatchii 220
ventricosus 195, 197
vespertinus (378)

(243-247, 252, 269, 356, 386, 413)
aduncus 182 (285)
aequisulcatus (371)
akihoensis 182
alatus 174, 183
albicans 177
albus 181
anatipes (429)
andersoni 203
antiguensis churuguarensis (451)
archon 177 (261)
athleta 209 (457)
atlanticola 203
bakeri 177
bakeri diazi 177 (255)
bavayi 203
beali 178, 180 (273)
bellus 175
bellus hemphilli 175, 177
bellus slevini 177
benedictus 181, 182
besseri 178
bodenbenderi 183
bosei 178, 180 (275)
bowersi 183
burdigalensis (451)
californicus 183
carrizoensis 178, 180 (272)
caurinus 182, 183, 185
cerrosensis 210
circularis 181, 196, 197, 267
circularis caucanus 198 (382)
circularis cornellanus 198 (380)
circularis venezuelanus 198 (381)
clemensae 195
coalingaensis 180, 182, 195 (283,

394, 1357)
commutatus 195, 196
compactus 197
cooperi (393)
coosensis (314)
crassus 212
cristobalensis (385)
dentatus 178, 181

denticulatus 189 (325)
deserti (378)

diegensis 178, 179, 180 (269)

cf. P. diegensis 179

dilleri 186, 187 (313)

dilleri variety 187

dregeri 172

duplex 185

eboreus sensecens (397)

erythraeensis 181

estrellanus 208

etchegoini 207 (431)

imbrifer 213

impostor 198 (394)
invalidus 200

irradians (210)

islandicus 187, 191, 192
islandicus pugetensis 190, 191, (333)
jacobaeus 174, 177
jeffersonianus 209
jessoensis (213)

juanensis 180
kagamianus 182
kaneharai (331)
kurosawaensis 187
laqueatus (262)
latiauratus 203

latissimus 209

linki 203

lohri 183, 185 (295, 296)
lunaris 180 (270)
macdonaldi 178
macloskéyi 203
madisonius 209
magnificus 209 (455)
magnolia 209

maximus 174

melii 209

meridionalis (211)
merriami 185
monotimeris 202
nakatombetsuensis 187 (315)
natoriensis 205 (418)
natoriensis subovalis 205
nevadanus 183, 209
newcombi 195
nodosiformis 209
nodosus 169, 209 (452)
notoensis 205 (421)
novaezelandiae 177
ochlockoneensis 178
ochlockoneensis violae 178, 180 (274)
oregonensis 182, 185 (300, 307)
oweni 183 (283)
parmeleei 206

perulus 181

pesfelis 205

philippii 195

plica 205 (422)

poulsoni 211, 212
praevasseli 205 (417)
propatulus 185 (297)
proteus (394)

purpuratus 172 (386)
purpuratus var. 200 (387)
pusio 211

pustulosus 213

rubidus 193, 211

vogdesi 181
yakatagensis 185
yamasakii 185 (302, 303)
yessoensis 172, 182, 183
Pecten (Aequipecten) bellilamellatus 203
deserti 200
gibbus circularis 199
purpuratus 198, 199
purpruatus subdolus 201
subdolus 201
Pecten (Blanckenhornia) oweni (292)
Pecten (Chlamys) bellilamellatus 203
flabellum 196
hamlini 205, 207 (416, 432)
hastatus 188-189 (322)
hastatus hericius 190
hastatus hindsii 194
hastatus ingeniosa 189 (322)
hericeus 190
hertleini (345)
hindsii 193, 194, 195
‘ hindsii jordani (342)
hindsii kincaidi 192, 195 (340)
hindsii navarchus 194
islandicus picoensis 194 (349)
islandicus pugetensis (333)
islandicus venturaensis 195
jordani 191 (339)
kindlei 207 (436)
latiauritus 204
latiauritus delosi (404)
lawsoni 189 (320)
miyatokoensis (329)
multirugosus 211, 212
multirugosus crassiplicatus (471)
nutteri 205, 207 (433)
opuntia 192, 193
parmeleei 206
rubidus 194
venturaensis 194 (350)
washburnei venturaensis (350)
wattsi 207 (434)
wattsi morani 207 (435)
Pecten (Convexopecten) josslingi 180
Pecten (Cyclopecten) cocosensis (485)
pernomus 213
rotundus 213
Pecten (Euvola) cataractes 181
Pecten (Flabellipecten) duplex (305)
stearnsii 178-180 pl. 29, 35 text fig. 8
Pecten (Hinnites) giganteus 211
Pecten (Janira) bellus hemphilli 175
bellus slevini (260)
stearnsii stearnsii 179
vogdesi 181
Pecten (Leptopecten) prevalidus 203 (401)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Pecten (Lituyapecten) coosensis 187
(314)
dilleri 186-187 pl. 35
falorensis (308)
poulcreekensis 186, 187 (310)
purisimaensis 187 (312)
yakatagensis 187
Pecten (Lyropecten) ashleyi 210
cerrosensis 210
dilleri 186
estrellanus 210 (461)
estrellanus catalinae (463)
estrellanus terminus (462)
gallegosi (464)
hopkinsi (445)
pretiosus 209
Pecten (Manupecten) kindlei (436)
Pecten (Nodipecten) condylomatus 209
Pecten (Notovola) sp. (242)
Pecten (Oppenheimopecten) hancocki
182 (284)
subbenedictus 180
vogdesi 181-182 pl. 29
Pecten (Pallium) swiftii etchegoini (422)
swiftii parmeleei 206
Pecten (Patinopecten) caurinus 172
coosensis (314)
dilleri 186
duplex (305)
expansus 183
hay wardensis (298)
hay wardensis calaverasensis (299)
healeyi 183-185 pl. 31, 33, 36, text
fig. 9
lohri (295)
merriami 185-186
nakatombetsuensis (315)
owenili (295)
propatulus 182, 186 (297)
purisimaensis (312)
yakatagensis (306)
Pecten (Pecten) archon (261)
auburyi 177 (257)
beali (273)
bellus 174-177 pl. 30, 32, text fig. 7
bellus hemphilli 175 (254)
carrizoensis (272)
coalingaensis (283)
dentatus 181
diegensis (269)
hastatus 189
hastatus var. (?) (323)
hawleyi (267)
heimi 182 (281)
hemphilli 175
islandicus hindsii 194
cf. islandicus jordani (337)
juanensis 182 (282)
lecontei 177 (258)
merriami 185
multirugosus 212
perulus 182 (286)
sanctaecruzensis (248)
slevini 177 (259)
stearnsii 178, 179
vogesi 181, 182
Pecten (Plagioctenium) abietis (368)
callidus 198 (374)
cerrosensis 210
circularis 197
circularis sequisulcatus (370)
cooperi 200, 201
demiurgus 198 (383)
deserti (379)
eldridgei (377)
ericellus 199
hakei 199
invalidus 200
neahensis 198 (367)
subdolus 201

Pecten (Propeamussium) ceciliae (481)
Pecten (Swiftopecten) otutumiensis 207
parmeleei 206
(Pecten) archon, Pecten (261)
auburyi, Pecten 177 (257)
beali, Pecten (273)
bellus, Pecten 174-177 pl. 30, 32,
text fig. 7
bellus hemphilli, Pecten 175 (254)
carrizoensis, Pecten (272)
coalingaensis, Pecten (283)
dentatus, Pecten 181
diegensis, Pecten (269)
hastatus, Pecten 189
hastatus var. (?), Pecten (323)
hawleyi, Pecten (267)
heimi, Pecten 182 (281)
hemphilli, Pecten 175
islandicus hindsii, Pecten 194
cf. islandicus jordani, Pecten (337)
jaunensis, Pecten 182 (282)
lecontei, Pecten 177 (258)
merriami, Pecten 185
multirugosus, Pecten 212
perulus, Pecten 182 (286)
sanctaecruzensis, Pecten (248)
slevini, Pecten 177 (259)
stearnsii, Pecten 178, 179
vogesi, Pecten 181
Pecten zone 323
Pectinacea 171 (199, 200)
pectinata, Cardiomya cf. C. 343
Cuspidaria (Cardiomya) 242 pl. 57
(1374)
Neaera 342
Pectinidae 171, 172 (201, 215-241)
Pectunculus 158, 159
septentrionalis 160
pectunculus, Arca 158
pedroana, Callista subdiaphana 270
Mysella 240 (677, 679)
Petricola 283 (979)
pellucida, Chama 227-228 pl. 43 (590)
peloritanus, Ciclopecten 213
penisulare, Anisodonta (685)
Basterotia 242
peninsularis, Basterotia 242
penita, Penitella 332, 333-334 pl. 56, 57
Pholadidea (1318)
Pholaidea aff. 333 (1314)
Pholas 333
Penitella 331, 332
chishimana 333, 334
conradi 332-333 (1311)
curvata 333
fitchi 333
gabbi 333
parva 332
penita 332, 333-334 pl. 56, 57
spelaeum 333
tubigera 332
turnerae 333 (1316)
xilophaga 332
(Penitella) chichimana, Pholadidea (1317)
lorenzana, Pholadidea 333 (1315)
pensylvanica, Lucina 242
Venus 242
perdix, Venus 274
Periploma 295, 336-337 (586, 1344)
cryphia 337, 338 (1342)
cryphia stenopa 337
inaequivalvis 336
planiuscula 337
cf. P. planiuscula 337
sanctaecrucia 337 (1339)
stenopa 337-338 pl. 41
teevani (1340)
venezuelana wiedenmayeri 337
(1341)
Periploma (Periploma) planiuscula 337

403

(Periploma) planiuscula, Periploma 337
Periplomatidae 336 (1336-1338)
perla, Poromya 341

pernomus, Amusium (Cyclopecten) 213
Cyclopecten 213-214 pl. 33
Pecten (Cyclopecten) 213

pernula, Mya 148
Nuculana 149

peroniana, Thyasira 257

Peronidia 284, 289

(Peronidia) bodegensis, Tellina 289-290

pl. 53 (1015)
nitda, Tellina (1013)
santarosae, Tellina 290 (1014)
solmonaeformis, Tellina 287 (1009)

perplana, Cardita (631)

perplicata, Verticordia 343 (1384)

perrini, Solen 308, 309 (1130)

perulus, Pecten (Pecten) 181, 182 (286)

peruviana, Anomia 223-224 pl. 40, 41

(S57)

pesfelis, Pecten 205

petagnae, Modiola 168

petitii, Venerupis 277

Petricola 282-283
buwaldi 283, 284
carditoides (982)
cordieri 279
costata 282
elliptica (959)
lapicida 282
lithophaga 283
lucasana 283 (980)
ochroleuca 293
pedroana 283 (979)
striata 282
sulcata 282

Petricola (Petricola) lucasana (980)

Petricola (Rupellaria) carditoides 283-

284 pl. 44

(Petricola) lucasana, Petricola (980)

Petricolidae 282 (976)

Phacoides 243, 250
acutilineatus 247, 249 (724)
annulatus 247
californicus 247
columbianum 249
joannis 251
megameris (692)
nuttallii 245
nuttalli antecedens 246
sanctaecrucis 250
xantusi 250 (754)

Phacoides (Here) andersoni (700)
richtofeni 244

Phacoides (Lucinisca) liana (710)
cf. nuttallii 245 (708)
nuttallii centrifugus (709)

Phacoides (Lucinoma) filosus 246
hannibali (727)

Phacoides (Miltha) childreni 250, 251
sanctaecrucis 250, 251 (743, 746)
xantusi 250

Phacoides (Parvilucina) approximata (736)
intensus 248

Phialopecten 209
triphooki 209

philippii, Pecten 195

Pholadacea 320 (1320)

Pholadidae 330-331, 334 (1303-1305)

Pholadidea 332 (1309)
loscombiana (1309)
penita (1318)
aff. penita 333 (1314)
sagitta 333

Pholadidea (Penitella) chishimana (1317)
lorenzana 333 (1315)

pholadis, Hiatella 326, 327 (1248)
Mytilus (1248)

Saxicava 326 (1248)

404

Pholas 169, 331
concamerata 333
crispatus 331
penita 333
picoensis, Pecten (Chlamys) islandicus
194 (349)
pilosa, Arca 158
pilsbryi, Zirfaea 331
Zirfaea cf. Z. 331-332
pinguis, Venus 269 (897)
Pitar 264, 267-268
newcombianus 268
Pitar (Megapitaria) squalidus 268
Pitaria 267, 268
arnoldi 268
newcombiana 268
Pitaria (Pitaria) tumens 267
(Pitaria) tumens, Pitaria 267
Placunanomia 224, 225 (563, 572, 582)
alope 225, 226 (537)
cepio 225, 226 (572)
colon 225
foliata (582)
inornata 225
ione 225
macroschisma 225
patelliformis 225
rudis 224
zealandica 225
Plagioctenium 195, 196
(Plagioctenium) abietis, Pecten (368)
callidus, Pecten 198 (374)
cerrosensis, Pecten 210
circularis, Aequipecten 197
circularis aequisulcatus, Pecten (370)
cooperi, Pecten 200, 201
demiurgus, Pecten 198 (383)
deserti, Pecten (379)
eldridgei, Pecten (377)
ericellus, Pecten 199
Plagiostoma gigantea 211, 212
(Plagioctenium) hakei, Pecten 199
invalidus, Pecten 200
neahensis, Pecten 198
subdolus, Pecten 201
plana, Thyasira (789)
planiuscula, Periploma (Periploma) 337
Periploma cf. P. 337
planulata, Mactra (Spisula) 314, 316
Spisula (Mactromeris) 312, 314, 316,
317
Spisula (Mactromeris) cf. S. (M.) 316-
317 pl. 57
planus, Cryptodon 256 (790)
Plastomiltha 250 (739)
Platiscelum 317
playasensis, Modiolus (Brachydontes)
(152)
plena, Macoma affinis 293 (1027)
Pleurodesma floridana 24]
Pleuromeris 233
plica, Pecten 205 (422)
plicata, Apolymetis (Hemimetis) (1057)
Venus 272
plicatella, Lopha (S40)
plumula kelseyi, Lithophaga 170 (183)
Lithophaga (186)
poculum kurosawaensis, Patinopecten
(Patinopecten) (311)
Pododesmus 223, 224-225 (564)
decipiens 224
foliatus 226 ($82)
macroschismus (580)
newcombei 226 (581)
puntarenensis 225 (S65)
rudis 224
Pododesmus (Monia) macrochisma
225-226 pl. 40, 41
Polymetis 297 (1055, 1056)
polynyma, Mactra 313

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

ponderosa, Arthemis 265 (878)
diegoana, Dosinia (Dosinia) 143, 265-
266 pl. 47, 49, 51 (877, 878)
jacalitosana, Dosinia 265
pontonia, Leda (52)
Nuculana 151 (52)
popofianus, Saxidomus 271 (912)
Porites (1182)
Poromya 340 (1360-1362)
anatinoides (1360)
gabbiana 341 (1363)
n. sp. 341
oregonensis 341
perla 341
teglandae 297, 341 (1366)
tenuiconcha 341
Poromya (Deratomya) equatorialis 340
(1368)
mactroides 340
soyoae (1369)
tenuiconcha 341
Poromyacea 340
Poromyacidae 340 (1358, 1359)
Poromyoida 340
Portlandia (59)
postulosus, Cyclopecten 213
poulcreekensis, Patinopecten (Lituya-
pecten) 186, 187 (310)
poulsoni, Hinnita 211, 212
Pecten 211, 212
Praesaccella 149 (46)
praetenus, Cochlodesma (Bontaea)
(1344)
praetenuis, Mya (1344)
praevalidus, Pecten (Leptopecten) 203
praevasseli, Pecten 205 (417)
Pratulum 262, 263
prelamellifer, Irus lamellifer (961)
pretiosus, Pecten (Lyropecten) 209
prevalidus, Pecten (Leptopecten) (401)
Prionodesmata 144
Pristes 239, 240
oblongus 240-241 pl. 44
pristinum, Clinocardium (8 38)
Pristiphora 240
oblonga 240
procerum, Cardium (Mexicardia) 260
Trachycardium (Mexicardia) 260
proficua, Tellina 299
profunda, Axinea 160
Glycymeris (Axinola) 159, 160-161

pl. 27
Prohinnites 211 (468)
prolongata, Cardita (Miodontiscus) 233
(636)
Venericardia (Miodontiscus) 233
prolongatus, Miodon 232, 233
Miodontiscus 233-234 pl. 56
Promantellum 215 (491)
parafragile (491)
propatulus, Patinopecten (297)
Pecten (Patinopecten) 182, 185, 186
(297)
Propeamussium 213 (481)
(Propeamussium) ceciliae, Pecten (481)
proteus, Pecten (394)
Prothyasira 255 (783)
Protocallithaca 277
Protocardia 262, 263
centifilosa 263
Protodonax 302 (1088)
elongatus (1088)
Protothaca 264, 276 (945-947)
grata 276 (949)
kovatschensis 277 (952)
laciniata 276
restorationensis 278 (955)
staminea spatiosa 277
cf. P. tenerrima (954)
Protothaca (Callithaca) tenerrima 277-

278, 279 pl. 51, 52
tenerrima alta 278-279 text fig. 12
Protothaca (Novacallithaca) euglypta
277
Protothaca (Protothaca) staminea 276,
278

thaca 276
(Protothaca) staminea hannibali, Paphia
Dit
staminea, Protothaca 276, 278
staminea, Venerupis 276
thaca, Protothaca 276
proxima, Tellina 292 (1019)
Psammacoma (Macoploma) medioameri-
cana 295
Psammobia 304 (1101-1104)
depressa 304
depressa caerulescens 304
depressa livida 304
depressa normalis 304
edentula 305
aff. edentula 305 (1108)
feroensis (1102)
vespertina 304
Psammobia (Tellina) feroensis (1102)
(Psammocola) edentula, Gari 305
Psammotaea 288
donacina 288
Psammotreta 297 (1058)
Psephidia 264, 279-280, 281
barbarensis 281
cymata 281, 282 (964)
lordi 280, 281 (963)
lordi ovalis 280
n. sp.? 281 (965)
ovalis 280 pl. 47, S1
salmonea 281 (966)
stephensae 143, 280-281 pl. 44
Psephis 279, 280
lordi 280
Pseuderiphyla 228
(Pseuderiphyla) remiensis, Crassatella
(593)
pseudobilirata, Pandora (Kennerlyia) 335
(1333)
Pseudochama 227
pseudoillota, Barbatia (Fugleria) S75
158 (108)
Pseudomiltha 250 (737)
Pseudosaxicava 326 (1245)
bernardi (1245)
Pteria 173
Pteromeris 233 (631)
Ptychina 256
pubescens, Mya 338 (1351)
Thracia 338 (1351)
pugetensis, Chlamys (“Chlamys’’) (333)
Chlamys hastata 191
Pecten (Chlamys) islandicus (333)
Pecten islandicus 190, 191 (333)
punctata, Clidiophora 336
Pandora (Heteroclidus) 336 pl. 42
puniceus, Brachidontes 166
puntarenensis, Pododesmus 225 (S65)
purisimaensis, Pecten (Lituyapecten) 187
(312)
Pecten (Patinopecten) (312)
purpurata, Chlamys 196
Chlamys (Argopecten) 200 (386)
purpuratus, Aequipecten 200 (389)
Pecten (Aequipecten) 198, 199
Pecten 172 (386)
subdolus, Pecten (Aequipecten) 201
var., Pecten 200 (387)
pusio, Pecten 211
pustulosus, Pecten 213

Q
quadragenarnium, Cardium (Dallocardia)
259-260 pl. 46

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

Laevicardium (Trachycardium) 259
quadrata, Corbula 241

Cryptomya (1212)

vancouverensis, Cryptomya 319
quadrigenerium, Cardium 259, 260 (829)
quintinensis, Crassinella 229 (598)
quirica, Nucula 145, 146 (27)

Nucula (Ennucula) (28)

R
radians, Lucina 247
radiata, Corbula (1234)
Siliqua 310
Tellina 284
radiatus, Solen 310
ramonensis, Panope 329 (1281)
Rastellum 221
recta, Modiola 166
Volsella 167
rectus, Modiolus 166-167 pl. 42
redondoensis, Aligena 236 (660)
Cardita (622)
Cardita ventricosa (622)
Cyclocardia ventricosa 231
reflexa, Venerupis 279
regius, Murex (177)
remiensis, Crassatella (Pseuderiphyla)
(593)
repenta, Didimacar (106)
restorationensis, Paphia (955)
Protothaca 278
reticulata, Semele 299
Tellina 299
revellei, Aequipecten 202
Mactrotoma 315 (1182)
Rexithaerus 290, 295-296
(Rexithaerus) indentata flagleri, Macoma
296 (1045)
indentata, Macoma 296, 297 pl. 52
indentata tenuirostris, Macoma 296
297 pl. 41, 50, 52
Rhomalea (915)
Rhomaleo (915)
thysomia, Venus 281 (968)
richardsoni, Cardium 263 (857)
Nemocardium centifilosum 264
richthofeni, Here 243
Lucina (Here) 243
Phacoides (Here) 244
Rochefortia 239 (674)
australis 239
golischi 240 (678)
tumida 239
rogersi, Lithophaga (Labis) attenuata
170 (188)
rosaceus, Solen 307, 308, 209, 310 pl. 48
Solen sicarius? 308
rosea, Corbula luteola 324
Diplodonta (Felania) 252
rossianus, Lembulus (44)
rostellata, Metis 298
rostrata, Arca 148, 149
Arca martini 148
Tellina 285, 334
rotunda, Kellia 237
rotundus, Pecten (Cyclopecten) 213
rubida, Chlamys (Chlamys) 188, 192,
193-194 pl. 35
rubida jordani, Chlamys 192 (341)
rubidus, Pecten 193, 211
Pecten (Chlamys) 194
rubropicta, Semele 299, 300 pl. 48
Semele cf. S. 299, 300 (1050)
rubrum, Cardium 236
ruderata, Tapes 277
rudis, Arcturus 229
Placunanomia 224
Pododesmus 224
rufa, Venus (915)
rufescens, Haliotis 234

rugosa, Donax 302
Nucula 146
Saxicava 326
Rupellaria 283 (977)
(Rupellaria) carditoides, Petricola 283-
284 pl. 44

S
Saccella 149
calkinsi 151 (54)
taphria 150
(Saccella) callimene, Nuculana 151 (51)
taphria, Nuculana 150-151 pl. 27
(55-58)
sacculifer, Modiolus 167-168 pl. 41
vosella 167
sacyi, Chlamys 203 (403)
Chlamys (Antipecten) (402)
sagamiensis, Dermatomya tenuiconcha
341 (1370)
sagaseri, Trachycardium 260 (830)
sagitta, Pholadidea 333
sakhalinensis, Haitella (1246)
salmonea, Maera 286
Psephidia 281 (966)
Tellina (Cadella) 286-287 pl. 53
Tellina (Moerella) 286
samarangae, Cardium 262
Nemocardium 262
sanctaecricis, Phacoides (Miltha) 250
Lucina (748)
Periploma 337 (1339)
Phacoides (Miltha) 251 (743, 746)
sanctaecruzensis, Pecten (Pecten) 174
(248)
santarosae, Tellina (Peronidia) 290 (1014)
santiaga, Crenella ecuadoriana 171 (196)
sardoa, Pecten 209
sarsii, Axinus (802)
Thyasira (802)
Saxicava 325, 326
abrupta (979)
albertensis (1244)
antarctica 327 (1251)
arctica 326 (1257)
arctica bilineata (1259)
californica 283
carditoides 283
gallicana 325
orientalis (1260)
pholadis 326 (1248)
rugosa 326
solida (1254)
striata 325
Saxicavidae 325
Saxidomus 264, 269, 271
gibbosus 269, 270 (905)
giganteus 271-272 (919)
(2) noblei (911)
nomurai 272 (923)
nuttalli 271-272
nuttalli latus 271, 272 pl. 50
opacus (914)
popofianus 271 (912)
vaquerosensis 272 (920-922)
sayana, Olivella 267
Scaeochlamys 205
Scalaricardita 229, 230 (611)
scalaris, Cardita 230, 231 (623)
Miodon 229
(Scapharca) trilineata, Arca 155
Scaphula 152
scarificata, Tivela 266, 267 (886)
schencki, Chione 275 (937)
Mytilus 163 (146)
Schizodus 257
Schizothaerus 317 (1187, 1194)
keenae 318 (1198, 1199)
nuttallii 317, 318 (1198)
nuttallii bighopensis (1197)

405

nuttallii kissyuensis 319 (1200)
schizotoma, Arca 155
Scolimytilus 164 (152)
Scolimytilus (Aedimytilus) adamsianus
164
Scrobicularia biangulata 298 (1065, 1066)
sculpturata, Ostrea 219 (S23)
sebetia, Bornia 238
Kellyia 238
secta, Macoma 295, 296
Tellina 296
Secitpecten 209 (459)
Securella 273, 274 (927)
ensifera 274
(Securella) kanakoffi, Chione 143,
274-276 pl. 49, 51
securis, Chione 274, 276
securis, Chione (Securella) 274
Venus 274
Semelangulus 286 (1004)
Semele 299 (1069-1073)
ashleyi 299-300 pl. 48
fausta 300
reticulata 299
rubropicta 299, 300 pl. 48
cf. S. rubropicta 299, 300 (1050)
species pl. 48
Semelidae 299 (1067)
Semeloidea 238
donaciformia 238
semiasperum, Cardium 262
Semipallium 205, 206 (426)
semiplicata, Chione 275 (932)
senescens, Chlamys eborea 202 (397)
walkerensis, Chlamsy eborea 202 (398)
Senila 152
septentrionalis, Glycymeris 160, 161
Pectunculus 160
(?septentrionalis) subobsoleta, Axinaea
159

Septifer 162, 165
bifurcatus 165-166 pl. 42
bifurcatus obsoletus 166 (156)
bilocularis 165
cumingil 166 (157)
grayanus 166 (160, 161)
keeni 166 (159)
margaritana 166 (162)
zeteki 166 (157)
(Septifer) bilocularis, Brachidontes 165
sequens, Ostrea vespertina 219 (518)
sericata, Diplodonta 254
sericatus, Axinopsis 157 (807)
Taras (Felaniella) 254
serricatus, Cryptodon 257
sericeus, Pecten 178, 180 (271)
serricata, Axinopsida 257-258 pl. 44 (808)
Serridens 240
oblonga 240
Serrula 303
(Serrula) gouldii, Donax 303 pl. 48, 57
sespeensis, Apolymetis cf. A. 297 (1059)
Macoma 298
shinjiense, Clinocardium 262 (848)
shinjiensis, Cardium (848)
sicarlus? rosaceus, Solen 308
sicarius, Solen 307, 308-309 pl. 49
Solen cf. 309 (1133)
Siliqua 307, 310-311
alisoensis 310 (1143)
lucida 311 pl. 49
patula 311 (1148)
radiata 310
simondsi (1144)
sloati 311 (1147)
sp. indet. (1145)
siliqua, Solen 309
Siliquaria 305
edentula 305
notata 305

406

similaris, Panope 329
simillima, Venus 274
Simomactra 315
simondsi, Siliqua (1144)
simplex, Anomia 223 (556)
Anomya 224
simpsoni, Pecten 209 (458)
sinuosus, Hinnites 211
sisquocensis, Arca (Arca) 153-154 pl. 27
Spisula 315 (1181)
slevini, Pecten bellus 177
Pecten (Janira) bellus (260)
Pecten (Pecten) 177 (259)
sloati, Silqua 311 (1147)
smirna, Ledina 149
Solecurtidae 305, 306
Solecurtus 306, 341 (1364)
californianus 306
lucidus 311
Solen 307, 309, 310
amethystus 304 (1101)
brevis 307
caribaeus 306
clallamensis 309 (1131)
divisus 306
ensis 309
fonesii 307
gibbus 305, 306
guineensis 305, 306
inaequivalvis 334
jonesii 307
krusensterni 309
magnus 309
minutus 325, 326
perrini 308, 309 (1130)
radiatus 310
rosaceus 307, 308, 309, 310 pl. 48
sicarius 307, 308-309 pl. 49
cf. sicarius 309 (1133)
sicarius? rosaceus 308
siliqua 309
squamosus (652)
tagal 305
tanozawaensis 308 (1129)
truncatus 307
bagina 307
vespertinus 304
Solenacea 307 (1124)
Solenidae 307 (1125)
solida, Hiatella 327 (1124)
Mactra 312
Panope generosa 328 (1272, 1274)
Panopea (1272)
Saxicava (1254)
Spisula 312
solidissima, Mactra (1166)
solidulus, Argopecten 195
Pecten 195, 196
solmonaeformis, Tellina (Peronidia) 287
(1009)
soricis, Gula 166
soror codercola, Pecten 178, 180 (278)
Pecten 178, 180 (277)
sowerbyi, Trapezium 272
soyae, Alucinoma (720)
Dermatomya tenuiconcha 341 (1369)
Poromya (Dermatomya) (1369)
Spaena 321
Spaniodon 235 (654)
nitidus (654)
Spaniodontella (654)
Spaniorinus 235 (654-656)
cossmanni (656)
spatiosa, Protothaca staminea 277
speciosa, Corbula 324 (1234)
Varicorbula (1234)
spelaeum, Penitella 333
spengleri, Panopaea 329
Sphaenia 321
elliptica (1209)

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

fragilis 321, 322
Sphaerella bulla (764)
Sphenia 319, 321 (1217)
binghami 321
californica 301, 319
decussata 321
elliptica 319
fragilis 321
cf. S. globula 321
luticola 321, 322
cf. S. luticola 321-322 pl. 56
pacificensis 322 (1218)
swainsoni 321
trunculus 322 (1220)
spinosella, Amussiopecten burdigalensis
(451)
Spisula 311, 312, 313, 316
albaria 312, 313
albaria coosensis 312, 313 (1161)
cameronis 315 (1174)
cf. S. catilliformis 314 (1167)
catilliformis alcatrazensis 314 (1168)
dolabriformis 314, 315, 317 (1171)
elongata 317
falcata 312, 314, 316, 317 (1169)
falcata brioniana 314 (1170)
longa 315 (1176)
ovalis 313
planulata 314, 316, 317
sisquocensis 315 (1181)
solida 312
strongi 315, 317 (1179, 1185)
Spisula (Hemimactra) mercedensis 316
mossbeachensis 315 (1175)
Spisula (Mactromeris) catilliformis 312,
313-314, 316 pl. 54
cf. S. (M.) falcata 314 pl. 54, 57
hamphillii 312, 315-316 pl. 54, 57
hamphilli orcutti 315 (1177)
mercedensis 312, 316 pl. 54
planulata 312, 316
cf. S. (M.) planulata 316-317
Spisula (Symmorphomactra) falcata 313
(Spisula) catilliformis, Mactra 313
falcata, Mactra 314
planulata, Mactra 316
Spondylus dalcifer (177)
lamarckii 321
Sportellidae 241 (681)
squalida, Cytherea 268
Dione 268
Macrocallista (Megapitaria) 269
Megapitaria 268-269, 274 pl. 50
squalidus, Pitar (Megapitaria) 268
squamatus, Pecten 212
squamosa decoriata, Chlamys 189
Lima 214
Mactra (652)
squamosus, Solen (652)
Stalagmium 170
staleyi, Paphia cf. (944)
staminea, Callithaca? cf. C. (951)
Cytherea 276
hannibali, Paphia (Protothaca) 277
orbella, Tapes 277
Paphia 276
Protothaca (Protothaca) 276, 278
spatiosa, Protothaca 277
Tapes 276
Venerupis (Protothaca) 276
Venus 276
Standella ovalis 313
stearnsi, Mytilus (Hormomya) 164, 165
stearnsiil, Cyclocardia 231 (616)
Patinopecten cf. 180 (276)
Pecten 176, 178, 179, 181
Pecten (Flabellipecten) 178-180 pl.
29, 35, text fig. 8
Pecten (Janira) stearnsii 179
Pecten (Pecten) 176, 178, 179

stearnsii, Pecten (Janira) 179
Venericardia (Cyclocardia) (616)
stenopa, Periploma 337-338 pl. 41
Periploma cryphia 337
stephensae, Psephidia 143, 280-281
pl. 44
stephensoni, Diplodonta 254 (776)
sternbergi, Mytilus (Crenomytilus)
coalingensis 143, 163-164 pl. 41
Stralopecten 206 (430)
ernestsmithi (430)
Striarca 153
striata, Aligena 235
Corbula 322
Cytherea 267
Donax 302
Petricola 282
Saxicava 325
strigata, Yoldia (S38)
Strombus glaea 321
strongi, Spisula 315, 317 (1179, 1185)
stultorum, Donax 266, 267
Tivela (Pachydesma) 266-267 pl. 50
(888)
subbenedictus, Pecten (Oppenheimopecten)
180
subcosta, Anomia 224 (561)
subdiaphana, Callista 269
Clementia (Compsomyax) 269, 270
Clementia (Compsomyax) aff. 270
(909)
Compsomyax 269-270 pl. 47, 57
(893)
Marcia 269-270
pedroana, Callista 270
Venerella (Compsomyax) 905
Venus 269
yazawaensis, Clementia (Compsomyax)
270 (908)
subdola, Chlamys (Argopecten) 196, 199,
201-202 pl. 30, 35
subdolus, Pecten (Aequipecten) purpuratus
201
Pecten (Artopecten) 201
Pecten (Plagioctenium) 201
subglobosa, Navea 332
Submantellum 215 (492)
submiguelensis, Chlamys (Lyropecten)
miguelensis 209
subnasuta, Tellina 293
subnodosa, Chlamys (Nodipecten) 205
subnodosus intermedius, Chlamsy (Nodi-
pecten) 209
Pecten (456)
subobsoleta, Axinaea (?septentrionalis) 159
Glycymeris 159, 160, 161 (125)
suborbicularis, Chironia 237
Kellia 236, 237
Mya 236
subovalis, Pecten natoriensis 205
subquadrata, Cardita (Carditamera)
232
Glans 232 pl. 43
Lazaria 232
subrugosa, Venus (928)
substriata, Montacuta (664)
Subtagelus 306 (1114)
subula, Lithophaga (Diberus) 170 (184,
185)

sugillata, Cytherea 274
sulcata, Corbula 322
Gregariella 168
Modiola 168
Modiolaria 168
Petricola 282
sulcatus, Modiolus 168
sulcicosta, Arca 155
supramontereyensis, Yoldia (63)
Yoldia cooperii 151, 152 (63)
suprastriata, Nucula 146-147 (32)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

swainsoni, Sphenia 321
swiftii, Chlamys (Swiftopecten) 172,
205, 208
etchegoini, Pecten (Pallium) (422)
parmeleei, Pecten (Pallium) 206
Pecten 204
Swiftopecten 173, 186, 191, 204-206
(Swiftopecten) cosibensis, Chalmys 205
donmilleri, Chlamys 207 (437)
etchegoini, Chlamys 207
herteroglypta, Chlamys 205
kindlei, Chlamys 205, 208
nutteri, Chlamys 208
obutumiensis, Pecten 207
parmeleei, Chlamys 206-208 pl. 31,
37, text fig. 10
parmeleei etchegoini, Chlamys 207
parmeleei, Pecten 206
swiftii, Chlamys 172, 205, 208
wattsi, Chlamys 207, 208
Symmorphomactra 313
(Symmorphomactra) falcata, Spisula 313

T
taberi, Chione undatella 274
tabiquita, Ostrea messor 222
tabogensis, Arca (Byssoarca) 157
taeniata, Panope 329
taffana, Lucina (Here) (697)
tagal, Solen 305
Tagelus 305-306 (111-113)
affinis longisinuatus 306
clarki 307 (1123)
divisus (1113, 1114)
gibbus (1113)
Tagelus (Tagelus) californianus 306-307
(Tagelus) californianus, Tagelus 306-307
takahashii, Pecten (294)
tamatavica, Nucula 146
tamurae, Chlamys 193 (346)
tanakai, Chlamys ingeniosa 195 (360)
tanozawaensis, Solen 308 (1129)
tantilla, Transennella 281, 282 pl. 44
(969-971, 973, 975)
tantillus, Venus 282
Tapes laciniata 277
opaca (913)
ruderata 277
staminea 276
staminea orbella 277
tennerima 277, 278
taphria, Leda 150
Nuculana (Saccella) 150-151 pl. 27
(55-58)
Saccella 150
Taras 252
antiquata 252
orbellus 252
parilis (772)
Taras (Felaniella) sericatus 254
taylori, Myrtea (Lucinoma) 246 (714)
tayloriana, Ostrea 217
teevani, Periploma 337 (1340)
teglandae, Poromya 297, 341
Teleodesmata 226
Tellidora (991)
Tellimya 241
tumida 239
Tellina 284 (991, 992, 1028, 1030)
albaria 292
albicans 289
alta 298
antoni 285
aurora (1058)
calcarea 290, 291
carpenteri 288
compressa 287
contabulata 293 (1030)
cryStallina 334
cuspidata 342

davisi (1003)
depressa 304
donacina 288
englishi 286 (1001)
fereonsis (1102)
flexuosa 255, 256
fragilis 293
fucata 305
gari (1095, 1102)
cf. idae (997)
inaequivalvis 295, 334
inquinata 292
insurana (1003)
intastriata 297
interrupta 285
irus (1028)
kesenensis 287 (1007)
lachiogramma 286
lanceolata 288
lechiogramma 286
ligamentina 295
mediterranea 324
meyeri 297 (1054-1056)
moesta (1017)
nasuta 293
nevadensis 286 (996)
nitida 289
obesa 298
obliqua (1024)
ooides (1143)
oudardi 287
proficua 299
proxima 292 (1019)
radiata 284
reticulata 299
rostrata 285, 334
secta 296
subnasuta 293
tener 288
tenuilineata 286
tenuilirata (1004)
tenuistriata 286
turgida 298
variabilis 304
variegata 288
virgata 285
Tellina (Angulus) carpenteri 288
variegata 288
Tellina (Cadella) salmonea 286-287
pl. 53
Tellina (Maera) lechriogramma 286
Tellina (Moerella) arenica 289 (1012)
carpenteri 288-289 pl. 53, 56
salmonea 286
Tellina (Oudardia) buttoni 289
modesta 287-288
Tellina (Peronidia) bodegensis 289-290
pl. 53 (1015)
nitida (1013)
santarosae 290 (1014)
solmonaeformis 287 (1009)
Tellina (Tellinella) idae 285-286 pl. 53
(997-999)
(Tellina) feroensis, Psammobia (1102)
Tellinacea 284 (983)
Tellinella 284, 285
(Tellinella) idae, Tellina 285-286 pl. 53
(997-999)
Tellinidae 284 (985-991)
tellinoides, Cumingia (1077)
Diplodonta 254
Lucina (774)
temblorensis, Lucina (Here) excavata 244
(705)
Temblornia 235, 238, 239
(Temblornia) frankiana, Bornia 143,
238-239 text fig. 11
keenae, Bornia (672)
triangulata, Bornia 238
tener, Tellina 288

407

tenera, Arca (109)
Barbatia (Fugleria) 158
Macoma 290
tennerima alta, Paphia (Callithaca) 278
alta, Protothaca (Callithaca) 278-
279, text fig. 12
Paphia 277
Protothaca (Callithaca) 277-278, 279
pl. 51,52
Protothaca cf. P. (954)
Tapes 277, 278
tenuiconcha, Dermatomya 341 pl. 56
Poromya (Dermatomya) 341
sagamiensis, Dermatomya 341 (1370)
soyoae, Dermatomya 341 (1369)
tenuilineata, Tellina 286 (1000)
tenuilirata, Tellina (1004)
tenuimbricata, Glycymeris 161 (132)
tenuirostris, Macoma aff. identata (1051)
Macoma (Rexithaerus) indentata 296,
297 pl. 41, 50, 52
tenuis, Nucula 146
Panope 329
tenuisculpta intensa, Lucina (Parvilucina)
248-249 pl. 46
Lucina (Myrtea) 248
Lucina (Parvilucina) 249
tenuissima, Yoldia cooperi 152 (64)
tenuistriata, Tellina 286 (1003)
terminus, Pecten (Lyropecten) estrellanus
(462)
Teredinidae 334 (1319, 1320)
Teredo (546)
bipalmulata 334
dorsalis (1322)
terminus, Chlamys (Lyropecten) estrel-
lanus 211
tetragona, Arca 153
thaca, Chama 276
Protothaca (Protothaca) 276
Venus 276
theca, Lopha (540)
thomasi, Ostrea 221
Thracia 295, 338, 339 (1349-1352)
corbuloidea 338
formosa (1357)
kakumana 339 (1354)
kanakoffi 143, 338-339 pl. 42
pubescens 338 (1351)
trapezoides (1353)
Thraciidae 338 (1345-1348)
thracioides, Mactra 267
Thurlosia 331
crispata 331
Thyasira 255, 256 (785, 787, 789)
albigena 257
barbarensis 257 (801)
bisecta 255
cygna 256 (792)
disjuncta 255 (780)
flexuosa 255 (802)
gouldii 255-257 pl. 43 (793)
cf. T. gouldii (798)
gouldii-Neptunea tabulata 257
inaequalis (789)
insignis (789)
peroniana 257
plana (789)
sarsii (802)
tokunagai 256 (793)
Thyasiridae 254-255 (777)
Thyella lamellosa 302 (1081)
Tibialectus otteri 168
tigris, Pecten 206 (426)
Timothynus (764)
titan, Ostrea 216
Tivela 264, 266
crassatelloides 267
scarificata 266, 267 (886)
tripla 266

408

vulgaris 266
Tivela (Pachydesma) stultorum 266-267
1.50

(Tivela) crassatelloides, Cytherea 266
tokyoensis, Macoma 293 (1036)
tokunagai, Thyasira 256 (793)
Tomburchus 236
topangensis, Anadara 156
tournali, Chlamys 209
Trachycardium 259 (824)

sagaseri 260 (830)

Trachycardium (Mexicardia) panamense 260

procerum 260 i
(Trachycardium) gorokuense, Cardium
260 (832) :
quadragenarium, Laevicardium 259
vaqueroensis, Cardium 260 (831)
trampasensis, Mytilus 163
transenna, Pecten 213
Transennella 264, 281-282
californica 281 (974)
galapagana 281-282
herviderana 281
joaquinensis 281
tantilla 281, 282 pl. 44 (969-971,
973, 975)
(Transennella?) conradiana, Cytherea 281
trapezia, Cardita (Glans) 232
Glans 231, 232
Trapezium sowerbyi 272
trapezoides, Anatina 336
Thracia (1353)
traskei, Lutraria? 270 (904)
Tresus 311, 317-318 (1187, 1198)
capax (1195)
maximus 317
nuttallii 319 pl. 54, 56 (1195, 1196)
pajaroanus 318 (1189)
triangulata, Bornia (Temblornia) 238
Donax 238
Trichomusculus 168
Trigonarca 153
Trigonella 266
(Trigonella) crassatelloides, Cytherea 266,
267
trigonula, Diplodonta 252
Trigonulina 343-344
ornata 343, 344
(Trigonulina) ornata, Verticordia 344
pl. 43
trilineata, Anadara 154-155, 157 pl. 28
(91)
Anadara (Anadara) 154-156 (99)
Anadara (Anadara) trilineata 155
Arca 156
Arca (Anadara) 155
Arca (Arca) 155
Arca (Scapharca) 155
calcarea, Anadara 154, 155, 156-157
pl. 28 (100)
calcarea, Arca (Anadara) 156
calcarea, Arca (Arca) 156
canalis, Anadara (Anadara) 156, 157
trilineata, Anadara (Anadara) 155,
274
trinominatus, Modiolus 167 (173)
triphooki, Phialopecten 209
tripla, Cytherea 266
Tivela 266
Venus 266
tropicalis, Ensis 310 (1142)
Tropithaca 276 (949)
Truncacila 144, 147
(Truncacila) castrensis, Acila 147-148
pl. 27
truncatus, Solen 307
trunculus, Sphenia 322 (1220)
tryblium, Pecten 185 (95, 301)
Tuangia 276 (950)
tuberculata, Ostrea 215

LEO GEORGE HERTLEIN AND U. S. GRANT, IV

tubigera, Pentiella 332
tumens, Cytherea 267
Mysella cf. M. 240
Pitaria (Pitaria) 267
Venus 267
tumida, Mysella 239-240 pl. 44, 45
Rochefortia 239
Tellimya 239
tumidus, Pecten 197
tunica, Pecten 203
Turcica caffea, Lucinoma annulata-257
turgida, Nucula (24)
Panomya arctica 330 (1295)
Tellina 298
turnerae, Penitella 333 (1316)
Turritella ocoyana (920)
variata (885)
twinensis, Apolymetis 298
Macoma 292
typus, Cuspidaria 342

U
unda, Arcopagia 298
undatella, Chione (Chione) 274
Chione (Chione) cf. C. (C.) 273-274
taberi, Chione 274
Venus 274
undulata, Cyathodonta 339
ungulata, Agerostrea 221
Ostrea 221
ungulatus, Ostracites 221
usta, Diplodonta (Felaniella) 253
Felania 253
Mysia (Felania) 253

Me
vagina, Solen 307
valentinensis, Pecten 174 (249)
vancouverensis, Cryptomya quadrata 309
Glycymeris 160 (128)
Metis 298
vanvlecki, Macoma 296 (1046)
Pecten 209
vaqueroensis, Cardium (Trachycardium)
260 (831)
Saxidomus 272 (920-922)
variabilis, Gobraeus 304
Tellina 304
variata, Turritella (885)
Varicorbula 323
speciosa (1234)
(Varicorbula) cf. bradleyi, Corbula 324
(1237)
gibbiformis, Corbula 323-324 pl. 57
granti, Corbula 324 (1236)
variegata, Cardita 232
Tellina (Angulus) 288
variegatus, Angulus 288
veatchii, Glycymeris 161
Ostrea 216, 219-22I1pl. 39, 40
Ostrea vespertina ($12)
Pecten 220
Veletuceta 159 (123)
Venatomya 319 (1209)
Veneracea 158, 264 (861)
Venerella 269 (895, 898)
Venerella (Compsomyax) subdiaphana
(905)
Venericardia 233
borealis 229, 230
californica 231 (618)
monilicosta 230
ventricosa 230, 231 (616)
yatesi 233 (635)
Venericardia (Cyclocardia) californica
(617)
inflata (624)
stearnsii (616)
Venericardia (Miodontiscus) prolongata
233

Veneridae 264 (862)
Venerupis 276
cordieri 279
gigantea (919)
irus (956)
lamellifera 279
multicostata 279 (962)
petitii 277
reflexa 279
Venerupis (Protothaca) staminea 276
venezuelana, Nucula 147 (35)
Ostrea (Alectryonia) vespertina
(525)
Ostrea vespertina 129 (525)
Pecten circularis 198 (381)
wiedenmayeri, Periploma 337 (1341)
ventricosa, Cardita 229, 230, 231 (611)
Cyclocardia 230, 231 pl. 43
montereyensis, Cardita (Cyclocardia)
(621)
montereyensis, Cyclocardia 231 (621)
redondoensis, Cardita (622)
redondoensis, Cyclocardia 231
Venericardia 230, 231 (616)
ventricosus, Pecten 195, 197
venturaensis, Pecten (Chlamys) 350
Pecten (Chlamys) islandicus 195
Pecten (Chlamys) washburnei 194
(350)
Venus (943)
adamsi 277
angustifrons 270 (901)
asperrina (930)
bilineata 274
bisecta 255
brevilineata 270 (902)
californiana 279 (931)
cancellata 272
concentrica 265
corbicula 266
crassicosta 276 (950)
cypria (943)
dombeii 276
dombeyi 276
dysera 272
entobapta 274
exalbida (897)
excavata 274
gigantea (894)
hermonvillensis (898)
ignobilis 276
lamellifera 279 (956)
lapicida 282
lithophaga 282, 283
lupinus 252
mariae (943)
neglecta 274
nuttalli 274, 277
opacus 271 (913)
opima (897)
pajaroana (1189)
pensylvanica 242
perdix 274
pinguis 269 (897)
plicata 272
rhysomia 281 (968)
rufa (915)
securis 274
simillima 274
staminea 276
subdiaphana 269
subrugosa (928)
tantillus 282
thaca 276
tripla 266
tumens 267
undatella 274
vera, Hiatella 327
Verticordia 343 (1382)
aequicostata 343 (1383)

MARINE PLIOCENE OF SAN DIEGO, CALIFORNIA

cardiiformis 343
granulosa (1381)
novemcostata 344
perplicata 343 (1384)
Verticordia (Trigonulina) ornata 344
pl. 43
verticordia, Cryptodon 343
Verticordiidae 343
verticordius, Hippagus 343
Vertipecten 183, 209
vespertina, Ostrea 216, 217 218-219, 220
221 pl. 39 (526)
Ostrea cf. 219 (528)
Ostrea haitensis 220
Psammobia 304
sequens, Ostrea 219 (518)
veatchii, Ostrea (512)
venezuelana, Ostrea (Alectryonia)
(525)
vespertinus, Gobraeus 304
Pecten (378)
Solen 304
vicaria, Notocorbula (1229)
vickeryi, Chione 275 (936, 937)
vieta, Nucula 147
violae, Pecten ochlockoneensis 178, 180
(274)
virgata, Tellina 285
virginica, Crassostrea (505)
Ostrea 216 (S05)
virginea, Cytherea 267
viridis, Axinopsis 258 (805)
virleti, Ostrea 219, 221 (526, 535, 536)
vogdesi, Pecten (Janira) 181
Pecten (Oppenheimopecten) 181-182
pl. 29
“Vola” 172
Volsella 166
directa (168)
recta 167
sacculifer 167

vulgaris, Gari 304
Tivela 266

W
walkerensis, Chlamys eborea senescens
202 (398)
Chlamys eboreus (398)
washburnei venturaensis, Pecten (Chlamys)
(350)
wattsi, Chlamys (Swiftopecten) 207, 208
morani, Pecten (Chlamys) 207
Pecten (Chlamys) 207 (434)
weaveri, Cardium (851)
Cyathodonta 339 (1355)
Weyla 174, 183 (247)
wiedenmayeri, Periploma venezuelana
337 (1341)
wiedeyi, Ostrea 219, 220, 221 (531)
Winckworthia 215

», «

xantusi, Lucina (Miltha) 250
Miltha (Miltha) 250-251 pl. 45
Miltha cf. M. (744)
Phacoides 250 (754)

xilophaga, Penitella 332

Xylophaga 334 (1322)
dorsalis (1322)

Xylophaginae 330, 334

Xylophagus 334

Xylotomea 334 (1323)

“Xylotrya” sp. 334

a6
yakatageniss, Pecten (Lituyapecten) 187
Pecten (Patinopecten) 185 (306)
yamasakii ninohensis, Patinopecten 185
(304)
Patinopecten (Patinopecten) yamasakii
(302)
Pecten 185 (302, 303)

409

yamasakii, Patinopecten (Patinopecten)
(302)
yatesi, Venericardia 233 (635)
yazawaensis, Clementia (Compsomyax)
subdiaphana 270 (908)
yessoensis, Pecten 172, 182, 183
yokohamaensis, Macoma calcarea 292
(1022)
yokoyamai, Lucina 245
Yoldia 148, 151 (59, 60)
angularis 151
arctica 151
cooperii 151, 152
cooperi kovatschensis 152, (68)
cooperi ochotensis 152 (65, 67)
cooperii supramontereyensis 151,
152 (63)
cooperi tenuissima 152 (64)
hyperborea 151
oregonensis 152 (62)
strigata (538)
supramontereyensis (63)
Yoldia (Kalayoldia) cf. Y. (K) cooperi
151-152 (61)
oregonensis (62)
zealandica, Anomia 225
Placunanomia 225
zebra, Byssoarca 153
zelandica, Zemysia 254
Zemysia 254
zelandica 254
zeteki, Septifer 166 (157)
Zirfaea 330, 331, 332
crispata 331
gabbi femii 332 (1308)
pilsbryi 331
cf. Z. pilsbryi 331-332
Zirphaea 331
crispata 331
gabbi 331
Zostera 204

Fig.

Fig.

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CaS

Slee

www ew
oe ON

36.

PLATE 27

Nucula (Ennucula) balboana n. sp. Holotype (California Academy of Sciences), from Loc. 12099 (CAS), San Diego well, Balboa Park, San
Diego, Calif. Length 13.4 mm.; height 10.7 mm.; convexity (both valves together) 7.2 mm. View of the exterior of the left valve. P.145

Nucula (Ennucula) balboana n. sp. Holotype. View of the exterior of the right valve. P.145

Nucula (Ennucula) balboana n. sp. Paratype (California Academy of Sciences), from same locality as the holotype shown in fig. 1. Length 11.4
mm. View showing hinge of a left valve. P.145

Nucula (Ennucula) balboana n. sp. Holotype. Dorsal view of specimen shown in figs. 1 and 2. P.145

Nucula (Lamellinucula) exigua Sowerby. Hypotype (University of California at Los Angeles), from Loc. 312 (UCLA), second ravine north of
Loe. 294 (UCLA), fifth ravine north (about 4 mile) of the Mexican boundary, at west face of a terrace, *4 mile east of the coast. Length 4.6
mm.; height 4.8 mm. View of exterior of a right valve. P. 146

Nucula (Lamellinucula) exigua Sowerby. View of the interior of the valve shown in fig. 5.

Acila (Truncacila) castrensis Hinds. Hypotype (Los Angeles County Museum), from Loc. 305 (LAM), 2400 feet east and 1350 feet south of the
northwest corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian, southwestern San Diego Co., Calif. (see U.S. Geol. Surv.
topog. map, San Ysidro quad., ed. 1943). Length 9.5 mm.; height 9.2 mm. View of the exterior of a left valve. P.147

Acila (Truncacila) castrensis Hinds. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length
10.1 mm.; height 8.2 mm. View of the exterior of a right valve.

Acila (Truncacila) castrensis Hinds. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length
9.8 mm.; height 8.2 mm. View of the exterior of a left valve.

. Acila (Truncacila) castrensis Hinds. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

9.0 mm.; height 8.0 mm. View of the exterior of a right valve.

. Nuculana (Saccella) taphria Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

19.3 mm.; height 12.9 mm. View of the exterior of a right valve which is very high in proportion to the length. P.150

. Nuculana (Saccella) taphria Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

16.4 mm.; height 9.6 mm. View of the exterior of a right valve.

. Nuculana (Saccella) taphria Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

13.7 mm.; height 8.4 mm.

. Glycymeris (Axinola) grewingki Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7.

Length 25.1 mm.; height 26.2 mm. View of the exterior of a left valve. P.159

. Glycymeris (Axinola) profunda Dall. Paratype (No. 696, California Academy of Sciences), from Pacific Beach, San Diego, Calif. Length 23

mm.; height 23.4 mm. View of the exterior of a left valve from the original lot of this species collected by Henry Hemphill.

. Nuculana (Saccella) taphria Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

18.5 mm.; height 10.3 mm. View of the exterior of a left valve.

. Nuculana (Saccella) taphria Dall. View of the interior of the specimen shown in fig. 16.
. Nuculana (Saccella) taphria Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length 21

mm.; height 12.3 mm.

. Glycymeris (Axinola) grewingki Dall. View of the interior of the specimen shown in fig. 14.
. Glycymeris (Axinola) profunda Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

26.4 mm.; height 26.5 mm. View of the exterior of a left valve.

. Glycymeris (Axinola) profunda Dall. View of the interior of the specimen shown in fig. 20.
. Glycymeris (Axinola) grewingki Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7.

Length 21.2 mm.; height 20 mm. View of the interior of a left valve.

. Glycymeris (Axinola) profunda Dall. View of the interior of the specimen shown in fig. 15.
. Glycymeris (Axinola) grewingki Dall. View of the exterior of the specimen shown in fig. 22.
. Glycymeris (Axinola) profunda Dall. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

23.2 mm.; height 25.3 mm. View of the exterior of a left valve.

. Arca (Arca) sisquocensis Reinhart. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

(incomplete) 11.2 mm.; height (incomplete) 5.5 mm. View of exterior of the upper portion of a right valve. This specimen virtually
disintegrated during the process of photography.

. Arca (Arca) sisquocensis Reinhart. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

23.8 mm.; height 16.4 mm. View of the exterior of an incomplete right valve. The specimen, very fragile, partially disintegrated during
preparation of a photograph.

. Glycymeris (Axinola) profunda Dall. Paratype (No. 696b, California Academy of Sciences), from Pacific Beach, San Diego, Calif. Length 20.8

mm.; height 21.8 mm. View of the exterior of a right valve from the type lot of this species collected by Henry Hemphill.

. Glycymeris (Axinola) profunda Dall. View of the interior of the specimen shown in fig. 28.
. Glycymeris (Axinola) profunda Dall. Hypotype (San Diego Society of Natural History), from Loc. 150 (SD), upper portion of the section of

Pliocene strata at Pacific Beach, San Diego, Calif. View of the hinge of the specimen shown in fig. 37, which is 32.8 mm. long (incomplete) and
35 mm. high.

. Arca (Arca) sisquocensis Reinhart. Enlarged view of hinge and ligamental area of the specimen shown in fig. 27.

. Arca (Arca) sisquocensis Reinhart. View of the interior of the specimen shown in fig. 26.

. Arca (Arca) sisquocensis Reinhart. View of the exterior of the specimen shown in figs. 27 and 31.

. Glycymeris (Axinola) profunda Dall. View of the interior of the specimen shown in fig. 25.

. Barbatia (Fugleria) illota Sowerby. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

18.3 mm.; height 13.3 mm. View of the exterior of a right valve. P. 157
Barbatia (Fugleria) illota Sowerby. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length
17.5 mm.; height 13 mm. View of the exterior of a left valve.

37. Glycymeris (Axinola) profunda Dall. View of the exterior of the same specimen shown in fig. 30.
. Barbatia (Fugleria) illota Sowerby. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length

(anterior end incomplete) 20.1 mm.; height 14.3 mm. View of the interior of a right valve.

. Barbatia (Fugleria) illota Sowerby. View of the exterior of the specimen shown in fig. 38.
. Barbatia (Fugleria) illota Sowerby. Hypotype (Los Angeles County Museum), from the same locality as the specimen shown in fig. 7. Length |

15.4 mm.; height 10.5 mm. View of the interior of a left valve. The lack of teeth in the central portion of the hinge is shown clearly in figures 38
and 40.

PLATE 27

Fig.

Fig. :

Fig. 3.

Fig.

Fig. 5.

Fig.
Fig.

Fig.

Fig. 9.

Fig

10

Ne

PLATE 28

Anadara trilineata Conrad. Hypotype (Los Angeles County Museum), from Loc. 305, 2400
feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian, southwestern San Diego Co., Calif. (see U.S. Geol. Survey
topog. map, San Ysidro quad., ed. 1943). Length 67.1 mm.; height 51 mm. View of the
interior of aright valve. P.154

Andara trilineata Conrad. Hypotype (University of California at Los Angeles), from Loc.
312 (UCLA), second ravine north of Loc. 294 (UCLA), fifth ravine north (about ‘4 mile) of
the Mexican boundary, at west face of a terrace %4 mile east of the coast. Length 31 mm.;
height 21 mm.; convexity (both valves together) 16 mm. View of dorsal area showing the
sharply pointed anterior margin when viewed from above. P.154

Andara trilineata Conrad. Hypotype (Los Angeles County Museum), from the same locality
as the specimen shown in fig. 1. Length 62 mm.; height 42 mm. View of the interior of a
right valve.

Anadara trilineata Conrad. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 52 mm.; height 40 mm. View of the exterior
of aright valve.

Anadara trilineata calearea Grant and Gale. Hypotype (California Academy of Sciences),
from the San Diego Well, Balboa Park, San Diego. Length 74 mm.; height 69 mm.;
convexity (both valves together) 46.6 mm. View of dorsal area showing rounded anterior
end when viewed from above. P.156

Anadara trilineata Conrad. View of the exterior of the specimen shown in fig. 3.

Anadara trilineata calcarea Grant and Gale. View of the interior of the right valve of the
specimen shown in fig. 5.

Anadara trilineata calcarea Grant and Gale. View of the interior of the left valve of the
specimen shown in fig. 5.

Anadara trilineata calcarea Grant and Gale. View of the exterior of the valve shown in fig.
8

. Anadara trilineata calcarea Grant and Gale. View of the exterior of the valve shown in fig.

(.

PLATE 28

Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

bo

3.

=

PLATE 29

Pecten (Oppenheimopecten) vogdesi Arnold. Hypotype (Los Angeles County Museum),
from Loc. 320A (LAM), chalky white sediment in exposure 100 feet behind the house at 835
South 32nd Street, San Diego. Length 105 mm.; height 84.4 mm. View of the exterior of a
left valve. P.181

Pecten (Flabellipecten) stearnsii Dall. Paratype (No. 525a, California Academy of Sci-
ences), from Pacific Beach. Length 90.6 mm.; height 78 mm. View of the exterior of a right
valve. This specimen is one of the original lot (H. Hemphill, No. 12138) of Pecten stearnsu.
P.178

Pecten (Oppenheimopecten) vogdesi Arnold. Hypotype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 1. Length 111 mm.; height 106.5 mm.
View of the exterior of a right valve. P.181

Pecten (Flabellipecten) stearnsti Dall. Left valve of the specimen shown in fig. 2.

Pecten (Oppenheimopecten) vogdesi Arnold. Hypotype (Stanford University), from 31st
and Logan Avenue, San Diego. Length 94.6 mm.; height (incomplete), 91.4 mm. View of the
exterior of a right valve, the umbonal portion lacking. P.181

Pecten (Oppenheimopecten) vogdesi’Arnold. View of the interior of the specimen shown in
fig. 1.

PLATE 29

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

bo

PLATE 30

Pecten (Pecten) bellus Conrad. Hypotype (California Academy of Sciences), from Pacific
Beach. Length 70.4 mm.; height 67.3 mm. View of the exterior of a right valve. This is
paratype No. 526b (H. Hemphill No. 12139) from the original lot of Pecten hemphillii Dall.
P.174

Pecten (Pecten) bellus Conrad. Hypotype (California Academy of Sciences), from Pacific
Beach. Length 72.5 mm.; height 64 mm. This is paratype No. 526 (H. Hemphill No. 12139)
from the original lot of Pecten hemphilli Dall.

Pecten (Pecten) bellus Conrad. Hypotype (Los Angeles County Museum), from Loc. 305
(LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T.19S., R. 2 W.,
San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length 26.6 mm.; height 24.3 mm. View of the exterior of a right valve. P. 174

Pecten (Pecten) bellus Conrad. Hypotype (California Academy of Sciences), from Pacific
Beach. Length 87.3 mm.; height 78.8 mm. This is paratype No. 526a (H. Hemphill No. 12139)
from the original lot of Pecten hemphillii Dall. Note the broad ribs on this specimen in
comparison with those on the specimen shown in fig. 1. P. 174

Chlamys (Chlamys) opuntia Dall. Hypotype (California Academy of Sciences), from Loc.
1183 (CAS), on Eagle Street just north of Quince Street, just east of Reynard Way, San
Diego. Length 34.8 mm.; height 37 mm. View of the exterior of a right valve. P.192

Chlamys (Chlamys) opuntia Dall. Hypotype (Los Angeles County Museum), from Loc. 107
(LAM), clay quarry at end of Arroyo Drive, San Diego. Length 38.4 mm.,; height 43.5 mm.
Chlamys (Argopecten) subdola Hertlein. Hypotype (California Academy of Sciences), from
Loc. 1413 (CAS), lower beds in section of Pliocene strata exposed at Pacific Beach. Length
45.5 mm.; height 45 mm. View of the exterior of a right valve. P.201

Chlamys (Argopecten) subdola Hertlein. View of the exterior of the left valve of the
specimen shown in fig. 7.

Pecten (Pecten) bellus Conrad, Hypotype (California Academy of Sciences), from Pacific
Beach. View of the exterior of the left valve of the specimen shown in fig. 4. This is the
exterior of the valve shown on plate 82, fig. 14.

. Chlamys (Chlamys) jordani Arnold. Hypotype (California Academy of Sciences), from Loc.

28893 (CAS), corner of India and Upas streets, San Diego. Length 13.8 mm.; height 26.2
mm. View of the exterior of a left valve of a juvenile specimen.

PLATE 30

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig. 7

PLATE 31

Pecten (Patinopecten) healeyi Arnold. Hypotype (San Diego Society of Natural History),
from Loc. 365 (SD), second ravine west of mouth of Rose Canyon, south slope of Mount
Soledad. Length 139 mm.; height 130 mm. View of the exterior of a left valve. P.183
Chlamys (Chlamys) hastata ellisi n. subsp. Holotype (Los Angeles County Museum), from
Loc. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S.,
R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1943). Length 66 mm.; height 68.5 mm. View of the exterior of a right valve. P.
190

Chlamys (Chlamys) hastata ellist n. subsp. Enlargement of a portion of the specimen
illustrated in fig. 2, showing the honeycomb-like sculpture covering the valve. P.190

Pecten (Patinopecten) healeyi Arnold. Paratype from the original lot of Pecten exrpansus
Dall (No. 527, California Academy of Sciences), from San Diego. Length 155 mm.; height
146 mm. View of the exterior of a left valve.

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 2. Length 31.9 mm.; height 36.8 mm. View of the
exterior of a small right valve. P. 206

Pecten (Patinopecten) healeyi Arnold. View of the exterior of right valve of specimen shown
in fig. 4. P. 183

Pecten (Patinopecten) healeyi Arnold. Hypotype (San Diego Society of Natural History),
from Loe. 37 (SD), Pacific Beach. Length 176 mm.; height 165 mm. View of the exterior of a
right valve (ends of hinge imperfect), showing radial ribs some of which bear two, some
three and occasionally four radial grooves. P. 183

PLATE 31

Fig.

Fig. 2

Fig. :

Fig.

Fig.
Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

tw

~

we

PLATE 32

Chlamys (Leptopecten) bellilamellata Arnold. Hypotype (California Academy of Sciences),
from Loe. 1400 (CAS), in upper portion of section of Pliocene strata at Pacific Beach, San
Diego. Length 16 mm.; height 16.5 mm. View of the exterior of a right valve. P.203

Chlamys (Leptopecten) bellilamellata Arnold. Hypotype (San Diego Society of Natural
History), Loc. 331 (SD), exposure back of house No. 3550 on Dove Street, San Diego. Length
14.7 mm.; height 13.8 mm. View of the exterior of a right valve. P. 203

Chlamys (Chlamys) ef. C. (C.) jordani Arnold. Hypotype (California Academy of Sciences),
from Loc. 28893 (CAS), corner of India and Upas streets, San Diego. Length (anterior side
imperfect) 28 mm.; height 31 mm. View of the exterior of a right valve with unusually fine
ribbing. P.191

Chlamys (Argopecten) circularis Sowerby. Hypotype (California Academy of Sciences),
from Loe. 1137 (CAS), 31st Street and Logan Avenue, San Diego. Length 28.5 mm.; height
28.6 mm.

Chlamys (Chlamys) jordani Arnold. Hypotype (California Academy of Sciences), from the
same locality as the specimen shown in fig. 3. Length 15.6 mm.; height 17.5 mm. P. 191
Chlamys (Chlamys) jordani Arnold. View of the left valve of the specimen shown in fig. 5.
P.191

Chlamys (Argopecten) ericellus Hertlein. Holotype (No. 2998, California Academy of
Sciences), from Loe. 1132 (CAS), Pacific Beach, San Diego. Length 29.1 mm.; height 28 mm.
View of the exterior of a right valve. P.199

Chlamys (Leptopecten) bellilamellata Arnold. Hypotype (California Academy of Sciences),
from Loc. 105 (CAS), Pacific Beach, San Diego. Length 12.8 mm.; height 12.9 mm. View of
the exterior of a left valve. P. 203

Chlamys (Argopecten) callida Hertlein. Hypotype (California Academy of Sciences), from
Loe. 1413 (CAS), from lower portion of the section of Pliocene strata at Pacific Beach.
Length 55.4 mm.; height 53.6 mm. View of the exterior of a left valve. P.198

. Chlamys (Argopecten) jordani Arnold. Hypotype (Los Angeles County Museum), from Loe.

107 (LAM), clay quarry at end of Arroyo Drive, San Diego. Length 45.7 mm.; height 47 mm.
View of exterior of a right valve, the ears lacking. P.191

. Chlamys (Argopecten) callida Hertlein. Hypotype (Los Angeles County Museum), from

Loe. 122 (LAM), Pacific Beach. Length 50 mm.; height 48.4 mm. View of the exterior of a
right valve. P.198

. Chlamys (Argopecten) jordani Arnold. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 10. Length 32.2 mm.; height 34 mm. P.191

. Chlamys (Argopecten) jordani Arnold. Hypotype (California Academy of Sciences), from

Loe. 1132 (CAS), Pacific Beach. Length 23.6 mm.; height 27.3 mm. View of the exterior of a
left valve. P.191

. Pecten (Pecten) bellus Conrad. Paratype of Pecten hemphilli Dall, (No. 526a, California

Academy of Sciences), from Pacific Beach. Length 87.3 mm.; height 77 mm. View of the
interior of a specimen (H. Hemphill No. 12139) from the original lot of Pecten hemphillit
Dall

5. Chlamys (Argopecten) circularis Sowerby. Hypotype (Los Angeles County Museum), from

Loe. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 198.,
R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1943). Length 24.6 mm.,; height 25.2 mm. View of the exterior of a left valve. P.
197

. Chlamys (Argopecten) circularis Sowerby. Hypotype (California Academy of Sciences),

from the same locality as the specimen shown in fig. 4. Length 24.6 mm.; height 25.2 mm.
View of the exterior of a right valve.

PLATE 32

Fig.

Fig.

Fig.

Fig.

Fig. 5.

Fig.
Fig.

Fig.

Fig.

Fig.

Fig.

w

10.

PLATE 33
Chlamys (Argopecten) invalida Hanna. Hypotype (California Academy of Sciences), from
Loe. 105 (CAS), Pacifie Beach. Length 48 mm.; height 46.4 mm. View of the exterior of a
right valve. P. 200
Chlamys (Chlamys) hastata hericius Gould. Hypotype (California Academy of Sciences),
from Loe. 2028 (CAS), Pacific Beach. Length 54 mm.; height 58 mm. View of the exterior of
aright valve.
Chlamys (Argopecten) invalida Hanna. Hypotype (California Academy of Sciences), from
Loe. 1179 (CAS), lower portion of the Pliocene section exposed at Pacific Beach. Length 35.5
mm.; height 33.3 mm. View of the exterior of a right valve. P. 200
Chlamys (Chlamys) hastata Sowerby. Hypotype (California Academy of Sciences), from
Loe. 1132 (CAS), Pacific Beach. Length 54 mm.; height 61 mm. View of the exterior of a left
valve. P. 188
Chlamys (Chlamys) hastata Sowerby. Hypotype (California Academy of Sciences), from
the same locality as the specimen shown in fig. 2. Length 43 mm.; height 48.6 mm. View of
the exterior of a right valve. P. 188
Chlamys (Chlamys) hastata Sowerby. View of the right valve of the specimen shown in fig.
4.
Cyclopecten (Cyclopecten) pernomus Hertlein. Hypotype (Los Angeles County Museum),
from Loc. 805A (LAM), west side of next gully east of Loc. 305 (LAM) at the same elevation.
Length 4.2 mm.; height 4.2 mm. View of the exterior of a left valve. P. 213
Chlamys (Argopecten) invalida Hanna. Hypotype (California Academy of Sciences), from
Loe. 1399 (CAS), in bluffs 100 to 200 yards south of the Eocene-Pliocene contact at Pacific
Beach. Length 35.4 mm.; height 33.4 mm. View of the exterior of a left valve. P. 200
Pecten (Patinopecten) healeyi Arnold. Hypotype (California Academy of Sciences), from
Loe. 1400 (CAS), upper strata in Pliocene section at Pacific Beach. Length 26.6 mm.; height
27.6 mm. View of the exterior of a juvenile right valve. Traces of vaguely defined radial ribs
are present along the ventral margin. The interior lacks any trace of ribs. P. 183
Chlamys (Argopecten) hakei Hertlein. Hypotype (San Diego Society of Natural History),
from Juniper and Boundary streets, San Diego. Length 160 mm.; height 143 mm. View of
the exterior of a left valve. P. 199

. Cyclopecten (Cyclopecten) pernomus Hertlein. Hypotype (Los Angeles County Museum),

from same locality as the specimen shown in fig. 7. Length 4.2 mm.; height 4.7 mm. View of
the interior of a left valve. P. 213

PLATE 33

Fig.

Fig.

Fig. ¢
Fig.

Fig.

Fig.

PLATE 34

Chlamys (Lyropecten) cerrosensis Gabb. Hypotype (Los Angeles County Museum), from
Loc. 305C (LAM), exposure at base of hill, 100 feet west and 440 feet south of the northeast
corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey
topog. map, San Ysidro quad., revision 1953). Length of hinge line 86 mm. View of the hinge
of a left valve showing the well developed crura. P. 209

Chlamys (Lyropecten) cerrosensis Gabb. Hypotype (Los Angeles County Museum), from
Loc. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T.19S.,
R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1943). Length 147 mm.; height 138 mm. View of the exterior of a right valve. P.
209

Chlamys (Lyropecten) cerrosensis Gabb. View of the interior of the valve shown in fig. 2.
Chlamys (Lyropecten) cerrosensis Gabb. View of the exterior of the valve shown in fig. 1.
Length 156 mm.; height 142 mm.

Chlamys (Argopecten) abietis abbotti n. subsp. Holotype (San Diego Society of Natural
History), from exposure at Frontier Housing Project, Loma Portal, San Diego. Length 129.3
mm.; height 117.3 mm. View of the exterior of a right valve. P.196

Chlamys (Chlamys) hastata ellisi n. subsp. Paratype (Los Angeles County Museum), from
the same locality as the specimen sh6wn in fig. 2. Length 17.9 mm.; height 20.8 mm. View of
the exterior of a left valve. P.190

PLATE 34

Fig.

Fig. 2

Fig. 3.

Fig.

Fig. §

Fig.

Fig.

Fig.

Fig. 9.

Fig.

Fig.

tw

PLATE 35

Chlamys (Leptopecten) latiaurata Conrad. Hypotype (University of California at Los
Angeles), from Loc. 312 (UCLA), second ravine north of Loc. 294 (UCLA), and fifth ravine
north (about 4 mile) of the Mexican boundary at west face of a terrace *4 mile east of the
coast. Length 17 mm.; height 17.3 mm. View of the exterior of a right valve. P. 203

Chlamys (Argopecten) subdola Hertlein. Hypotype (California Academy of Sciences), from
Loc. 1401 (CAS), first canyon west of Rose Canyon, south slope of Mount Soledad. Length 64
mm.; height 61.3 mm. View of the exterior of a right valve. P. 201

Chlamys (Leptopecten) latiaurata Conrad. View of the interior of the specimen shown in
fig. 1.

Pecten (Lituyapecten) dilleri Dall. Hypotype (University of California at Los Angeles),
from Loe. 309 (UCLA), corner of India and Upas streets, San Diego. Length 88.6 mm.;
height 88 mm. View of the exterior of a right valve. P.186

Chlamys (Argopecten) subdola Hertlein. View of the left valve of the specimen shown in fig.
2)

Chlamys (Chlamys) rubida Hinds. Hypotype (San Diego Society of Natural History), from
Loc. 4736 (SD), India Street near Spruce Street, San Diego. Length 59.8 mm.; height 64 mm.
View of the exterior of a left valve.

Pecten (Lituyapecten) dilleri Dall. View of the exterior of the left valve of the specimen
shown in fig. 4. ¢

Chlamys (Chlamys) rubida Hinds. Hypotype (Los Angeles County Museum), from Loe. 107
(CAS), clay quarry at end of Arroyo Drive, San Diego. Length 57.9 mm.,; height 52.6 mm.
View of the exterior of aright valve, the anterior ear imperfect. P. 193

Chlamys (Argopecten) subdola Hertlein. Hypotype (San Diego Society of Natural History),
from Loe. 408 (SD), road cut 0.1 mile east of Euclid Avenue on north side of Market Street,
San Diego. Length 40.5 mm.; height 41.8 mm. View of the exterior of a right valve. P. 201

. Pecten (Flabellipecten) stearnsii Dall. View of the interior of the specimen shown on plate

29, fig. 2. P.178

. Lima (Limaria) orcutti n. sp. Paratype (Los Angeles County Museum), from Loc. 305C

(LAM), exposure at base of hill, 100 feet west and 440 feet south of the northeast corner of
Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog.
map, San Ysidro quad., revision 1953). Length 38.6 mm.; height 43.2 mm. View of the
interior of aright valve. P. 215

PLATE 35

Fig.

Fig.

Fig. ¢
Fig.

Fig. £

Fig.

Fig. 7

Fig.

Fig. 9.

tw

ol

PLATE 36

Chlamys (Argopecten) abietis abbotti n. subsp. Holotype (San Diego Society of Natural
History), from cut in exposure of strata at Frontier Housing Project, Loma Portal, San
Diego. Length 129.0 mm.; height 118.0 mm. View of the exterior of a left valve. Fine
fringing lamellae on the sides of the ribs on the upper half of the shell are shown in this
illustration. P. 196

Lima (Limaria) orcutti n. sp. Holotype (Los Angeles County Museum), from Loc. 305
(LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19S., R. 2 W.,
San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length 35.5 mm.; height 43 mm. View of the exterior of a right valve. P. 215

Lima (Limaria) orcutti n. sp. View of the interior of the specimen shown in fig. 2.

Lima (Limaria) orcutti n. sp. Paratype (Los Angeles County Museum), from the same
locality as the specimen shown in figs. 2 and 3. Length 27.6 mm.; height 34.5 mm. View of
the exterior of a left valve.

Lima (Limaria) orcutti n. sp. View of the interior of the specimen shown in fig. 4.

Chlamys (Argopecten) abietis abbotti n. subsp. View of the interior of the right valve of the
specimen shown in fig. 1.

Chlamys (Lyropecten) cerrosensis Gabb. Hypotype (California Academy of Sciences), from
Loe. 12142 (H. Hemphill Coll.), from San Diego. Length 137 mm.; height (incomplete) 111
mm. View of the exterior of a right valve showing the strong radial striations over the
entire valve. P.209 ”

Pecten (Patinopecten) healeyi Arnold. Hypotype (California Academy of Sciences) from
Loc. 105-(CAS), Pacific Beach, San Diego. Length 28.4 mm.; height 29.5 mm. View of the
exterior of a small left valve. P. 183

Pecten (Patinopecten) healeyi Arnold. Hypotype (California Academy of Sciences), from
Loe. 105 (CAS), Pacifie Beach, San Diego. Length 37 mm.; height 38.8 mm. View of the
exterior of a small right valve showing the smooth early umbonal area. See also plate 33,
fig. 9. P. 183

PLATE 36

Fig.

Fig.

Fig. ¢

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

~]

PLATE 37

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from
Loc. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19S.,
R. 2 W., San Bernardino Base and Meridian, southwestern San Diego Co., Calif. (see U.S.
Geol. Survey topog. map, San Ysidro quad., ed. 1943). Length 43.6 mm.; height 48.8 mm.
View of the exterior of a left valve. P. 206

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length (incomplete) 46.0 mm.; height
(incomplete) 86.5 mm. View of a portion of a right valve on which the radial folds are only
faintly developed and concentric undulation is almost lacking. P. 206

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 43.6 mm.; height 48.5 mm. View of the
exterior of a right valve. P. 206

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 56.6 mm.; height 62.5 mm. View of the
exterior of a right valve. P. 206

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (San Diego Society of Natural History),
from Loc. 4735 (SD), India Street near Spruce Street, San Diego. Length 64.8 mm.; height
71.6 mm. View of the interior of a right valve showing cardinal crura. The end of the
anterior ear is imperfect as a result of accidental damage since the exterior was drawn as
shown in text fig. 10. P. 206

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length (incomplete) 54 mm.; height 83.6 mm.
View of a portion of a large right valve. P. 206

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 72.0 mm.; height 81.2 mm. View of the
exterior of a left valve. P. 206 7

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 11.5 mm.; height 12.8 mm. View of the
exterior of a juvenile right valve.

Chlamys (Swiftopecten) parmeleei Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 8.3 mm.; height 9 mm. View of the
exterior of a juvenile left valve.

. Chlamys (Swiftopecten) parmeleet Dall. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length 66 mm.; height 75.2 mm. View of the
exterior of a left valve.

PLATE 37

Fig.

Fig.

Fig.
Fig.

Fig. 5.

Fig.

Fig.

Fig.

Fig.

ol

PLATE 38

Ostrea (Agerostrea) megodon Hanley. Hypotype (University of California at Los Angeles),
from Loc. 2420 (UCLA), soft yellow Pliocene sands exposed in bluffs along Pacific Beach,
about ' mile southeast of False Point, La Jolla quadrangle, San Diego. Height (maximum)
37 mm.: width (maximum) 26.0 mm. View of the exterior of the lower valve. P. 221

Ostrea angelica Rochebrune. Hypotype (University of California at Los Angeles), from Loc.
303 (UCLA), first prominent cut on west side of the road, at lower entrance to Mt. Hope
Cemetery between Imperial Avenue and old Cuyamaca Railroad (36th Street), San Diego.
Height (beak to ventral margin) 113.3 mm.; width 81 mm. View of the exterior of a lower
valve. P. 216

Ostrea angelica Rochebrune. View of the interior of the specimen shown in fig. 2.

Ostrea erici Hertlein. Hypotype (Los Angeles County Museum), from Loc. 124 (LAM), shell
and echini stratum 15 feet below the school floor level of “Snyder's Continuation School.”
Height (beak to ventral margin) 69.6 mm.; width 50.4 mm. View of the interior of an upper
valve. P. 217

Ostrea Agerostrea) megodon Hanley. View of the exterior of the upper valve of the
specimen shown in fig. 1.

Ostrea erici Hertlein. Hypotype (Los Angeles County Museum), from Loc. 107 (LAM), clay
quarry at end of Arroyo Drive, San Diego. Height (beak to ventral margin) 65.8 mm.; width
58.6 mm. View of the exterior of an upper valve and marginal portion of the lower valve. P.
217

Ostrea (Agerostrea) megodon Hanley. View of the interior of the lower valve shown in fig.
ile

Ostrea erici Hertlein. Hypotype (Los Angeles County Museum), from the same locality as
the specimen shown in fig. 6. Height (beak to ventral margin) 90 mm.; width 86.5 mm. View
of the exterior of a lower valve.

Ostrea erici Hertlein. Hypotype (Los Angeles County Museum), from the same locality as
the specimen shown in fig. 6. Height 97 mm.; width (incomplete) 69.5 mm. View of the
interior of a lower valve.

PLATE 38

Fig.

Fig.

Fig. «

Fig.

Fig. 5.

Fig.
Fig.

Fig.

Fig. 9.

ue

on

PLATE 39

Ostrea vespertina Conrad. Hypotype (California Academy of Sciences), from Loc. 36555
(CAS), south side of Tijuana River near the mouth of the valley, at base of hill south of
monument road and east of Border Naval Reservation |= Loc. 305A (LAM)]. Height 48
mm.; width 37.5 mm. View of the lower of the lower valve showing denticles along the
dorsal margin. P. 218

Ostrea vespertina Conrad. Hypotype (California Academy of Sciences), from the same
locality as specimen shown in fig. 1. Height 46.4 mm.; width 37.4 mm. View of the interior of
an upper valve, showing muscle impression and denticles along dorsal margin. P. 218
Ostrea vespertina Conrad. Hypotype (University of California at Los Angeles), from Loc.
312 (UCLA), second ravine north of Loc. 294 (UCLA) and fifth ravine north (about 4 mile)
of the Mexican boundary, at west face of terrace %4 mile east of the coast. Height 40.6 mm.;
width 33.1 mm. View of the interior of an upper valve, showing muscle impression and
denticles along dorsal margin. P. 218

Ostrea veatchii Gabb. Holotype (No. 4502, Academy of Natural Sciences of Philadelphia).
Cedros Island, Lower California; Pliocene. Height 75 mm.; width 69 mm. View showing
interior of a left valve, completely Jacking denticles along the dorsal margin.

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum) from Loc. 305 (LAM),
2400 feet east and 1350 feet south of the northwest corner of Sec. 8. T. 19 S., R. 2 W., San
Bernardino Base and Meridian, southwestern San Diego Co. (see U.S. Geol. Survey topog.
map, San Ysidro quad., ed. 1943). Height 53.5 mm.; width 46 mm. View of exterior of lower
valve showing fluting and area of attachment. P. 218

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum), view of upper valve of
the specimen shown in fig. 5. P. 218

Ostrea vespertina Conrad. Hypotype (California Academy of Sciences). View of the exterior
of the specimen shown in fig. 2. P. 218

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum), from the same locality
as the specimen shown in fig. 5. Height 69 mm.; width 74 mm. View of a rather round lower
(left) valve.

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum). Upper valve of the
specimen shown in fig. 8. P. 218

PLATE 39

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

Fig.

il.

to

PLATE 39

Ostrea vespertina Conrad. Hypotype (California Academy of Sciences), from Loc. 36555
(CAS), south side of Tijuana River near the mouth of the valley, at base of hill south of
monument road and east of Border Naval Reservation [= Loc. 305A (LAM)]. Height 48
mm.; width 37.5 mm. View of the lower of the lower valve showing denticles along the
dorsal margin. P. 218

Ostrea vespertina Conrad. Hypotype (California Academy of Sciences), from the same
locality as specimen shown in fig. 1. Height 46.4 mm.; width 37.4 mm. View of the interior of
an upper valve, showing muscle impression and denticles along dorsal margin. P. 218
Ostrea vespertina Conrad. Hypotype (University of California at Los Angeles), from Loc.
312 (UCLA), second ravine north of Loc. 294 (UCLA) and fifth ravine north (about 4 mile)
of the Mexican boundary, at west face of terrace %4 mile east of the coast. Height 40.6 mm.,;
width 33.1 mm. View of the interior of an upper valve, showing muscle impression and
denticles along dorsal margin. P. 218

Ostrea veatchii Gabb. Holotype (No. 4502, Academy of Natural Sciences of Philadelphia).
Cedros Island, Lower California; Pliocene. Height 75 mm.; width 69 mm. View showing
interior of a left valve, completely Jacking denticles along the dorsal margin.

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum) from Loc. 305 (LAM),
2400 feet east and 1350 feet south of the northwest corner of Sec. 8. T. 19 S., R. 2 W., San
Bernardino Base and Meridian, southwestern San Diego Co. (see U.S. Geol. Survey topog.
map, San Ysidro quad., ed. 1943). Height 53.5 mm.; width 46 mm. View of exterior of lower
valve showing fluting and area of attachment. P. 218

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum), view of upper valve of
the specimen shown in fig. 5. P. 218

Ostrea vespertina Conrad. Hypotype (California Academy of Sciences). View of the exterior
of the specimen shown in fig. 2. P. 218

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum), from the same locality
as the specimen shown in fig. 5. Height 69 mm.; width 74 mm. View of a rather round lower
(left) valve.

Ostrea vespertina Conrad. Hypotype (Los Angeles County Museum). Upper valve of the
specimen shown in fig. 8. P. 218

PLATE 39

Fig.

Fig.

Fig. :

Fig. 4.

Fig.

Fig.

1.

te

PLATE 40

Ostrea veatchii Gabb. Hypotype (San Diego Society of Natural History), from Loc. 6307
(SD), Pacific Beach, San Diego. Length 146.5 mm.; height (including spines) 116.5 mm. View
of exterior of a large valve to which other smaller valves are attached. P. 219

Anomia peruviana d’Orbigny. Hypotype (Los Angeles County Museum), from Loc. 305C
(LAM), exposure at base of hill, 100 feet west and 440 feet south of the northeast corner of
Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog.
map, San Ysidro quad., revision 1953). Length 16 mm.; height 12.5 mm. View of exterior of
asmall upper valve, the margin imperfect. P. 223

Pododesmus macrochisma Deshayes. Hypotype (Los Angeles County Museum), from Loc.
305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19S., R. 2
W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1943). Length 79 mm.; height 73 mm. View of the exterior of an upper valve. P.
225

Ostrea veatchii Gabb. Hypotype (San Diego Society of Natural History). View of the
interior of the specimen shown in fig. 1. Margin completely lacks denticles. P. 219

Ostrea veatchii Gabb. Hypotype (Los Angeles County Museum), from Cedros Island, Lower
California, Mexico; Pliocene. Length 100 mm.; height 106.5 mm. View of the exterior of the
lower valve showing deep plications and spines. P. 219

Ostrea veatchii Gabb. Hypotype (Los Angeles County Museum). View of the interior of the
specimen shown in fig. 5. The margins are devoid of denticles. See also fig. 4 on plate 39. P.
219

PLATE 40

Fig.

Fig.

Fig.
Fig.

Fig.
Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

Fig.

a.

COSA

10.

13.
14.

il5},

ol

16.

PLATE 41

Gregariella chenui Recluz. Hypotype (Los Angeles County Museum) from Loc. 305 (CAS),
2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length 4.6 mm.; height 2.5 mm. View of the exterior of a right valve. P. 168

Modiolus sacculifer Berry. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length (incomplete) 22 mm.; height 10 mm. View
showing the projecting anterior end of a left valve. P. 167

Modiolus sacculifer Berry. View of the exterior of the specimen shown in fig. 2.

Modiolus sacculifer Berry. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length (anterior end incomplete), 49 mm.; height 34
mm. Ventral margin imperfect. P. 167

Gregariella chenui Recluz. View of the interior of the specimen shown in fig. 1.

Periploma stenopa Woodring. Hypotype (Los Angeles County Museum), from Loc. 305A
(LAM), west side of next gully east of Loc. 305 (LAM) at the same elevation. Length 56.5
mm.; height 38.4 mm. View of exterior of a left valve. P. 337

Periploma stenopa Woodring. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 6. Length (posterior end incomplete) 57 mm.; height
40.5 mm. Dorsal view. P. 337

Anomia peruviana d’Orbigny. Hypotype (California Academy of Sciences), from Loc. 1400
(CAS), strata in upper part of Pliocene section at Pacific Beach. Length 35.5 mm.; height
(incomplete) 35.8 mm. View of the exterior of an upper valve, the dorsal area incomplete. P.
223

Pododesmus macrochisma Deshayes. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 62 mm.; height 58.9 mm. View of the
exterior of an upper valve. P.225 -

Mytilus (Crenomytilus) coalingensis sternbergi new subspecies. Paratype (Los Angeles
County Museum), from Loc. 302 (LAM) exposure across the street from the house at 2840
Columbia Street, San Diego. Length (incomplete) 48.8 mm.; height (incomplete) 34 mm.
View of the interior of the umbonal portion of a left valve. P.163

. Crenella inflata Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 3 mm.; height 2.3 mm. View of the exterior
of aright valve. P.171

2. Pododesmus macrochisma Deshayes. Hypotype (University of California at Los Angeles),

from Loe. 2420 (UCLA), soft sands of Pliocene age at Pacific Beach. Length 52.5 mm.;
height 46.8 mm. View of the interior of an upper valve. P. 225

Pododesmus macrochisma Deshayes. View of the exterior of the specimen shown in fig. 12.
Mytilus (Crenomytilus) coalingensis sternbergi n. subsp. Holotype (Los Angeles County
Museum), from Loc. 107 (LAM), 100-foot bluff with fossiliferous concretions in clay quarry
at end of Arroyo Drive, San Diego. Length 238 mm.; height 134 mm. View of the exterior of
the left valve. P. 163

Macoma (Rexithaerus) indentata tenuirostris Dall. Hypotype (Los Angeles County Mu-
seum), from the same locality as the specimen shown in fig. 1. Length 29.3 mm.; height 16
mm. View of the exterior of a right valve. P. 297

Hinnites giganteus Gray. Hypotype (Los Angeles County Museum), from strata of Pliocene
age at Pacific Beach. Length 73.0 mm.; height 76.4 mm. View of the exterior of an upper
valve. P.211

PLATE 41

Fig.

Fig.

Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

ile

DH

10.

11.

PLATE 42

Gregariella chenui Recluz. Hypotype (Los Angeles County Museum), from Loc. 305C
(LAM), exposure at base of hill 100 feet west and 440 feet south of the northwest corner of
Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog.
map, San Ysidro quad., revision 1953). Length 4.6 mm.; height 2.5 mm. Enlarged view of
the exterior of a right valve, also illustrated on plate 41, fig. 1.

Pandora (Heteroclidus) punctata Conrad. Hypotype (University of California at Los
Angeles), from Loc. 1386 (UCLA), Dosinia beds in cut bank along a ravine road just below
the southeast corner of the Federal Building in Balboa Park, San Diego. Length (in-
complete) 28 mm.; height (incomplete) 12 mm. View of the hinge of a left valve. P.336
Pandora (Heteroclidus) punctata Conrad. Hypotype (University of California at Los
Angeles), from the same locality as the specimen shown in fig. 2. Length (incomplete) 34.5
mm.; height (incomplete) 13.8 mm. View of the hinge of a right valve. P.336

Aeidimytilus adamsianus Dunker. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 18.9 mm.; height 7.2 mm. View of the
exterior of a right valve. P. 164

Aeidimytilus adamsianus Dunker. View of the interior of a specimen shown in fig. 4.
Septifer bifurcatus Conrad. Hypotype (San Diego Society of Natural History), from Loe. 47
(SDSC), south side of Tijuana River near mouth of valley; east side of mouth of prominent
gully west of Goat Canyon, southeast 4, Sec. 8, T. 19 S., R. 2 W., (See U.S. Geol. Survey
topog. map, San Ysidro quad., ed. 1953). Length 18.3 mm.; height 10.3 mm. View of the
interior of a left valve. P.165

Modiolus rectus Conrad. Hypotype (Los Angeles County Museum), from Loc. 305A (LAM),
west side of next gully east of Loc. 305 (LAM) at the same elevation. Length (anterior end
incomplete) 55 mm.; height 41.8 mm. View of the exterior of a right valve. P. 166

Gregariella chenui Recluz. View of the interior of the specimen shown in fig. 1.

Pandora (Heteroclidus) punctata Conrad. Hypotype (San Diego Society of Natural His-
tory), from Loc. 21 (SD), embankment at the beach at west end of Diamond Street, Pacific
Beach. Length 41.5 mm.; height 25.8 mm. View of the exterior of a right valve. P.336
Pandora (Heteroclidus) punctata Conrad. View of the exterior of the left valve of the
specimen shown in fig. 9.

Thracia kanakoffi n. sp. Holotype (Los Angeles County Museum), from Loe. 291 (LAM), silt
beds exposed in a gully in the center of the south '% Sec. 27, T. 4. N., R. 15 W., San
Bernardino Base and Meridian; '2 mile south of the Humphrey railroad station, Los
Angeles Co., Calif.; Pico formation, middle Pliocene. Length 81.0 mm.; height 54.2 mm.
View of the exterior of the right valve. P. 338

. Septifer bifurcatus Conrad. View of the exterior of the specimen shown in fig. 6.
. Thracia kanakoffi n. sp. Paratype (San Diego Society of Natural History), from Loc. 34

(SD), northeast corner of India and Thorn streets, San Diego. Length 48 mm.; height 34.4
mm. View of the exterior of a left valve.

4. Thracia kanakoffi n. sp. View of the left valve of the specimen shown in fig. 11.
Fig. 15.

Thracia kanakoffi. Dorsal view of the specimen shown in figs. 11 and 12. A low ridge near
the right posterior dorsal margin, a characteristic feature of this species, is visible in this
view.

PLATE 42

Fig.
Fig. :
Fig. ¢

Fig.

Fig.

Fig.
Fig.

Fig.
Fig.
Fig.
Fig.

Fig.
Fig.

Fig.

Fig.
Fig.

Fig.
Fig.

Fig.

Fig.
Fig.

Fig. :
Fig. !
Fig. :
Fig. :

Fig. 2
Fig. :

Fig.
Fig.

Fig

Fig.

be

20.
_ Thyasira gouldii Philippi. Hypotype (University of California at Los Angeles), from Loc.

PLATE 43

Milneria minima Dall. Hypotype (Los Angeles County Museum), from Loc. 305 (LAM),
2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian, southwestern San Diego Co., Calif. (see U.S. Geol. Survey
topog. map, San Ysidro quad., ed. 1943). Length 5.3 mm.; height 3.2 mm. View of the
exterior of a right valve. P. 234

Milneria minima Dall. View of the interior of the specimen shown in fig. 1.

Cyclocardia ventricosa Gould. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 16.2 mm.; height 14.9 mm. View of the
interior of a left valve. P. 231

Cyclocardia occidentalis Conrad. Hypotype (University of California at Los Angeles), from
Loc. 2359 (UCLA), in small canyon parallel to and about 0.2 mile west of the mouth of Rose
Canyon and 0.4 mile north of Garnet Avenue, La Jolla quad., San Diego. Length 11.6 mm.;
height 12 mm. View of the interior of a right valve. P. 230

Cyclocardia occidentalis Conrad. Hypotype (University of California at Los Angeles), from
North Snyder School, Cabrillo Freeway, San Diego. Length 14 mm.; height 14 mm. View of
the interior of a left valve. P.230

Cyclocardia occidentalis Conrad. View of the exterior of the valve shown in fig. 5.
Diplodonta (Felaniella) cornea Reeve. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length (incomplete) 8.5 mm. View showing
hinge of a right valve. P. 253

Cyclocardia ventricosa Gould. View of the exterior of the specimen shown in fig. 3.
Cyclocardia occidentalis Conrad. View of the exterior of the specimen shown in fig. 4.

. Cyclocardia occidentalis Conrad. Hypotype (University of California at Los Angeles), from

the same locality as the specimen shown in fig. 4. Length 11 mm.; height 11 mm. View of the
exterior of asmall right valve. P. 230

. Cyclocardia occidentalis Conrad. Hypotype (University of California at Los Angeles), from

the same locality as the specimen shown in fig. 4. Length 9.5 mm.; height 9.8 mm.

. Chama pellucida Broderip. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 26.6 mm.; height (incomplete) 27 mm. View
of the exterior of an upper valve. P. 227

. Diplodonta (Felaniella) cornea Reeve. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length 10.5 mm.; height 10.5 mm. View of the
interior of a left valve. P. 253

_ Milneria minima Dall. View of enlarged portion of the specimen shown in fig. 2, showing

hinge. ?

. Chama pellucida Broderip. View of the interior of the specimen shown in fig. 12.
. Glans subquadrata Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 5.5 mm.; height 3.7 mm.

. Thyasira gouldii Philippi. Hypotype (Los Angeles County Museum), from the same locality

as the specimen shown in fig. 1. Length 4.1 mm.,; height 4.3 mm. P. 255

_ Glans subquadrata Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 4.5 mm.; height 3.3 mm. View of the
exterior of a left valve. P. 232

. Glans subquadrata Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 4.6 mm.; height 2.9 mm. View of the interior
of aright valve. P. 232
Diplodonta (Felaniella) cornea Reeve. View of the exterior of the specimen shown in fig. 13.

294 (UCLA), 200 feet north of the Mexican boundary and 4 mile from the coast. Pliocene
exposure in east-west ravine, tributory to a larger south-north ravine at right angle in first
terrace above the Tiajuana River plain. Length 8.1 mm.; height 8.1 mm. View of the exterior
of aright valve. P.255

. Glans subquadrata Carpenter. View of the interior of the specimen shown in fig. 16.
. Verticordia (Trigonulina) ornata d@’Orbigny. Hypotype (Los Angeles County Museum), from

the same locality as the specimen shown in fig. 1. Length 5.3 mm.; height 4.3 mm. View of
the exterior of a left valve. P. 344

_ Crassinella branneri Arnold. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 8.7 mm.; height (incomplete) 8.0 mm. View
of the interior of a left valve, the apical portion lacking. P. 228

. Crassinella branneri Arnold. Hypotype (Los Angeles County Museum), from the same
ypotyy »

locality as the specimen shown in fig. 1. Length 7.0 mm.; height 6.1 mm. View of the interior
of aright valve. P. 228

3. Verticordia (Trigonulina) ornata d’Orbigny. View of the exterior of the right valve of the

specimen shown in fig. 23.

. Verticordia (Trigonulina) ornata d’Orbigny. View of the interior of the specimen shown in

fig. 26.

_ Crassinella branneri Arnold. View of the exterior of the specimen shown in fig. 24.

. Crassinella branneri Arnold. View of the exterior of the specimen shown in fig. 25.

. Glans subquadrata Carpenter. View of the exterior of the specimen shown in fig. 19.

. Verticordia (Trigonulina) ornata d’Orbigny. View of the interior of the specimen shown in

fig. 23.

PLATE 43

Fig.

Fig.

Fig.

bo

as

PLATE 44

Aligena diegoana n. sp. Paratype (Los Angeles County Museum), from Loc. 305A (LAM),
west side of next gully east of Loc. 305 (LAM) at the same elevation. Length 6.3 mm.; height
5.3 mm. View of the exterior of a right valve. P. 235

Mysella tumida Carpenter. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 2.4 mm.; height 2.0 mm. View of the
exterior of a right valve. P. 239

Mysella tumida Carpenter. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 2.3 mm.; height 1.8 mm. View of the
exterior of a left valve. P. 239

Mysella tumida Carpenter. View of the interior of the specimen shown in fig. 2.

Mysella tumida Carpenter. View of the interior of the specimen shown in fig. 3.

Aligena diegoana n. sp. View of the interior of the specimen shown in fig. 1.

Mysella tumida Carpenter. Hypotype (Los Angeles County Museum), from Loe. 305 (LAM),
2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length 2.9 mm.; height 2.1 mm. View of the interior of a left valve. P. 239

Mysella tumida Carpenter. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 7. Length 3.2 mm.; height 2.7 mm. View of the
exterior of a left valve. P. 239

Pristes oblongus Carpenter. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 3.4 mm.; height 2.6 mm.

. Pristes oblongus Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 2.9 mm.; height 2.3 mm. View of the interior
of aright valve. P. 240

. Kellia laperousti Deshayes. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 4.0 mm.; height 3.3 mm. View of the interior
of a left valve. P. 237

. Mysella tumida Carpenter. View of the exterior of the specimen shown in fig. 7.
. Pristes oblongus Carpenter. View of the exterior of the specimen shown in fig. 9.
. Pristes oblongus Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 3.0 mm.; height 2.6 mm. View of the interior
of a left valve. P. 240

. Petricola (Rupellaria) carditoides Conrad. Hypotype (San Diego Society of Natural His-

tory), from Loe. 331 (SD), 200 feet north of the Mexican boundary and “4 mile from the
coast, exposure of strata of Pliocene age in east-west ravine tributary to a larger south-
north ravine at right angle, in first terrace above the Tiajuana river plain. Length 29.8 mm.;
height 15.7 mm. View of the exterior of a left valve. P. 283

. Petricola (Rupellaria) carditoides Conrad. View of the interior of the specimen shown in fig.

15.

. Axinopsida serricata Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 3.5 mm.; height 3.3 mm. View of the interior
of a left valve. P. 257

. Axvinopsida serricata Carpenter. View of the exterior of the specimen shown in fig. 17.
. Kellia laperousii Deshayes. View of the exterior of the specimen shown in fig. 11.

Transennella tantilla Gould. Hypotype (Los Angeles County Museum), from Loc. 305C
Length 3.7 mm.; height 3.0 mm. P. 282

. Psephidia stephensae n. sp. Holotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 3.0 mm.; height 2.7 mm. View of the interior
of aright valve. P. 280

2. Psephidia stephensae n. sp. Paratype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 4.7 mm.; height 2.6 mm. View of the interior
of aright valve. P. 280

. Transennella tantilla Gould. (Los Angeles County Museum), from the same locality as the

specimen shown in fig, 27. Length 5.8 mm.; height 4.8 mm.

. Psephidia stephensae n. sp. Holotype. View of the exterior of the specimen shown in fig. 21.
. Transennella tantilla Gould. Hypotype (University of California at Los Angeles), from Loe.

1386 (UCLA), Dosimia beds in cut bank 338 feet farther along the ravine road (from Loc.
1385), just below the southeast corner of the Federal Building, Balboa Park, San Diego.
Length 7.0 mm.; height 6.0 mm. View of the exterior of a left valve. P. 282

. Psephidia stephensae n. sp. Paratype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 3.9 mm.; height 3.2 mm. View of the interior
of a left valve. P. 280

. Transennella tantilla Gould. Hypotype (Los Angeles County Museum), from Loc. 309

(LAM), two canyons east of Kate Sessions School; approximately 0.3 mile west of Balboa
Avenue from U.S. Highway 101. Length 5.5 mm.; height 4.5 mm. View of the interior of a
left valve. P. 282

PLATE 44

Fig.
Fig.
Fig. <

Fig.
Fig. 5.

Fig.
Fig.
Fig.
Fig. 9.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.
Fig.

Fig.

PLATE 45

Lucina (Lucinisca) nuttalli Conrad. Hypotype (Los Angeles County Museum), from Loc.
305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2
W., San Bernardino Base and Meridian, southwestern San Diego Co., (see U.S. Geol. Survey
topog. map, San Ysidro quad., ed. 1943). Length 26.6 mm.; height 19.8 mm. View of the
exterior of a right valve. P.245

2. Lucina (Lucinisca) nuttalli Conrad. View of the interior of the specimen shown in fig. 1.

17.

Lucina (Lucinisca) nuttalli Conrad. Hypotype (los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 25.8 mm.; height 18.9 mm. View of the
exterior of a left valve.

Lucina (Lucinisca) nuttalli Conrad. View of the interior of the specimen shown in fig. 3.
Pristes oblongus Carpenter. Hypotype (Los. Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 3.3 mm.; height 3.0 mm. View of the
exterior of a right valve. P.239

Aligena diegoana n. sp. Paratype (Los Angeles County Museum), from Loe. 305A (LAM),
west side of next gully east of Loc. 305 (LAM) at the same elevation. Length 5.7 mm.; height
5.1 mm. View of the exterior of a right valve. P. 235

Aligena diegoana n. sp. Holotype (Los Angeles County Museum), from the same locality as
the specimen shown in fig. 1. Length 7.9 mm.; height 6.1 mm. View of the interior of a right
valve. P. 235

Pristes oblongus Carpenter. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 4.1 mm.; height 4.0 mm. View of the
exterior of a left valve. P. 239

Pristes oblongus Carpenter. View of the interior of the specimen shown in fig. 5.

. Aligena diegoana n. sp. Paratype from the same locality as the specimen shown in fig. 1.

Length 8.0 mm.; height 6.4 mm. View of the interior of a left valve. P. 235

. Aligena diegoana n. sp. Paratype (Los Angeles County Museum), from the same locality as

the specimen shown in fig. 1. Length 8.5 mm.; height 6.7 mm. View of the exterior of a right
valve. P. 235

. Pristes oblongus Carpenter. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 3.2 mm.; height 2.7 mm. View of the
exterior of a left valve. P. 239

_ Aligena diegoana n. sp. Paratype (Los Angeles County Museum), from the same locality

as the specimen shown in fig. 1. Length 7.5 mm.,; height 6.0 mm. View of the exterior of a
right valve. P.235

. Miltha (Miltha) xantusi Dall. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 6. Length 61.0 mm.; height 60.0 mm. View of the
exterior of a left valve which has been bored by a predator. P. 250

. Miltha (Miltha) xantusi Dall. View of the interior of the specimen shown in fig. 14.
. Miltha (Miltha) xantusi Dall. Hypotype (California Academy of Sciences), from Loe. 1402

(CAS), on end of point between Cabrillo Canyon and a gulch about 100 meters south of the
west end of Laurel Street bridge across Cabrillo Canyon, Balboa Park, San Diego. Length
72.5 mm.; height 68.8 mm. View of the exterior of a right valve. P. 250

Miltha (Miltha) wantusi Dall. Hypotype (California Academy of Sciences), from the same
locality as the specimen shown in fig. 16. Length 58.0 mm.; height 61.3 mm. View of a right
valve, smaller and more ovate in outline than the specimen shown in fig. 16 P. 250

PLATE 45

Fig.

Fig.

Fig. :

Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.
Fig.
Fig.
Fig.
Fig.

Fig.

Fig.

Fig. 2

Fig. :

Fig. %

PLATE 46

Lucina (Here) excavata Carpenter. Hypotype (Los Angeles County Museum), from Loc. 305
(LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19S., R. 2 W.,
San Bernardino Base and Meridian, southwestern San Diego Co., (see U.S. Geol. Survey
topog. map, San Ysidro quad., ed. 1943). Length 15.5 mm.; height 14.2 mm. View of the
exterior of a left valve. P. 244

Lucina (Here) excavata Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen illustrated in fig. 1. Length 17 mm.; height 17 mm. View of
the interior of a left valve.

Lucina (Here) excavata Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen illustrated in fig. 1. Length 19 mm.; height 19 mm. View of
the interior of a right valve.

Nemocardium (Keenaea) centifilosum Carpenter. Hypotype (San Diego Society of Natural
History), from the corner of India and Upas streets, San Diego. Length 16 mm.; height 16
mm. View of the exterior of a right valve. P. 263

Nemocardium (Keenaea) centifilosum Carpenter. View of the left valve of the specimen
shown in fig. 4.

Lucina (Parvilucina) intensa Dall. Syntype No. 698D (California Academy of Sciences),
from the San Diego well, Balboa Park, San Diego. Length 7.7 mm.; height 6.5 mm. View of
the exterior of a left valve. P. 247

Lucina (Parvilucina) intensa Dall. View of the interior of the specimen shown in fig. 6.
Lucina (Lucinisca) nuttalli antecedens Arnold. Hypotype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 1. Length 18.3 mm.; height 16.9 mm.
View of the exterior of a right valve. P. 246

Lucina (Lucinisca) nuttalli antecedens Arnold. Hypotype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 1. Length 17 mm.; height 15.38 mm.
View of a left valve. P. 246

_ Nemocardium (Keenaea) centifilosum Carpenter. Hypotype (California Academy of Sci-

ences), from Loc. 12078 (CAS) San Diego well, Balboa Park, San Diego. Length 16.5 mm.;
height 16.5 mm. View of the exterior’of a right valve. P. 263

. Lucina (Epilucina) californica Conrad. Hypotype (San Diego Society of Natural History),

from Loc. 80 (SD), middle part of gulch about 1/3 mile west of the mouth of Rose Canyon,
south slope of Mount Soledad, San Diego. Length 13.4 mm.; height 13.5 mm. View of the
exterior of aright valve. P. 247

. Lucina (Lucinoma) annulata Reeve. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length 44.6 mm.; height 38.5 mm. View of the
exterior of aright valve. P. 247

_ Lucina (Lucinisca) nuttalli antecedens Arnold. View of the interior of the specimen shown

in fig. 8.

_ Lucina (Lucinisca) nuttalli antecedens Arnold. View of the interior of the specimen shown

in fig. 9.

5. Nemocardium (Keenaea) centifilosum Carpenter. View of the interior of the specimen

shown in fig. 10.

_ Lucina (Epilucina) californica Conrad. View of the interior of the specimen shown in fig. 11.
7. Lucina (Parvilucina) intensa Dall. Hypotype (Los Angeles County Museum), from Loc.

305A (LAM), from west side of next gully east of Loe. 305 (LAM) at the same elevation.
Length 6.0 mm.; height 5.3 mm. View of the exterior of a left valve. P. 247

_ Cardium (Dallocardia) quadragenarium Conrad. Hypotype (Los Angeles County Museum),

from the same locality as the specimen shown in fig. 1. Length (incomplete) 60 mm.,; height
(incomplete) 49 mm. View of the interior dorsal portion of a right valve. P. 259

. Lucina (Lucinoma) annulata Reeve. Hypotype (Los Angeles County Museum), from the
) YE .

same locality as the specimen shown in fig. 1. Length 60.8 mm.; height 56.9 mm. View of the
interior of a right valve. P. 247

_ Cardium (Dallocardia) quadragenarium Conrad. View of the exterior of the specimen

shown in fig. 18.

_ Cardium (Clinocardium) nuttalli Conrad. Hypotype (Los Angeles County Museum), from

Loc. 107 (LAM), 100-foot bluff with fossiliferous concretions in clay quarry at end of Arroyo
Drive, San Diego. Length 80 mm.; height 82.4 mm.

_ Lucina (Parvilucina) intensa Dall. Hypotype (Los Angeles County Museum), from Loc. 318

(LAM), Knox Ranch hill, just above the gates and the cow shed; 200 feet from the road and
30 feet above the valley floor, near Mexican boundary. Length 6.4 mm.; height 6.9 mm. View
of the interior of a right valve. P. 247

_ Cardium (Dallocardia) quadragenarium Conrad. Hypotype (California Academy of Sci-

ences), from Loe, 1402 (CAS), on end of point between Cabrillo Canyon and a gulch about
100 meters south of the west end of Laurel Street bridge across Cabrillo Canyon in Balboa
Park, San Diego. Length 50 mm.; height 50.5 mm. View of the exterior of a left valve. P. 259

PLATE 46

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

10.

PLATE 47

Pandora (Pandorella) bilirata Conrad. Hypotype (Los Angeles County Museum), from Loc.
305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, TH19'S. Rez
W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1943). Length 13 mm.; height 7.5 mm. View of the interior of the specimen shown
on Plate 48, fig. 14. P. 335

Dosinia (Dosinia) ponderosa diegoana n. subsp. Paratype (California Academy of Sciences),
from Loc. 1402 (CAS), on end of a point between Cabrillo Canyon and a gulch about 100
meters south of the west end of the Laurel Street bridge across Cabrillo Canyon, Balboa
Park, San Diego. Length (incomplete) approximately 91.5 mm. View showing hinge of a left
valve. P. 265

Dosinia (Dosinia) ponderosa diegoana n. subsp. Paratype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 1. Length 114 mm.; height 111 mm.
View of the interior of a right valve. P. 265

Compsomyax subdiaphana Carpenter. Hypotype (California Academy of Sciences), from
Loc. 1404 (CAS), southeast corner of India and Upas streets, San Diego. Length 41.6 mm.,
height 35 mm. View of the exterior of the right valve. P. 269

Psephidia ovalis Dall. Hypotype (Los Angeles County Museum), from Loc. 305C (LAM),
exposure at base of hill, 100 feet west and 440 feet south of the northeast corner of Sec. 8, T.
19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San
Ysidro quad., revision 1953). Length 4.2 mm.; height 3 mm. View of the exterior of a left
valve shown on plate 51, fig. 9. P. 280°

Dosinia (Dosinia) ponderosa diegoana n. subsp. Paratype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 1. Length 117 mm.; height 120 mm.
View showing dorsal area of a specimen. P. 265

Compsomyax subdiaphana Carpenter. View showing the dorsal area of both valves of the
specimen shown in fig. 4.

Dosinia (Dosinia) ponderosa diegoana n. subsp. Holotype (California Academy of Sciences),
from the same locality as the specimen shown in fig. 2. Length 121 mm.; height 130 mm.
View of the exterior of the right valve. P. 265

Psephidia ovalis Dall. Hypotype (Los Angeles County Museum), from the same locality as
the specimen shown in fig. 5. Length 4.1 mm.; height 3.1 mm. View of the exterior of a right
valve shown on plate 51, fig. 8. P. 280

Dosinia (Dosinia) ponderosa diegoana n. subsp. View of the dorsal area of both valves of the
holotype shown in fig. 8. P. 265

PLATE 47

Fig.

Fig.
Fig. 3.
Fig.
Fig. 5.

Fig.
Fig.

Fig.
Fig.
Fig.
Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

Fig.

Fig.
Fig.

th

18.
Lg!

PLATE 48

Semele rubropicta Dall. Hypotype (Los Angeles County Museum), from Loe. 305C (LAM),
exposure at base of hill, 100 feet west and 440 feet south of the northeast corner of Sec. 8, T.
19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San
Ysidro quad., revision 1953). Length 42.5 mm.; height 35.5 mm. View of the exterior of a left
valve. P.300

Semele rubropicta Dall. View of the exterior of the right valve of the specimen shown in fig.
1

Semele ashleyi n. sp. Paratype (Los Angeles County Museum), from Loc. 305 (LAM), 2400
feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length 29 mm.; height 23.6 mm.

Semele species. Hypotype (Los Angeles County Museum), from the same locality as the
specimen shown in fig. 1. Length 5.5 mm.; height 4.4 mm. View of the exterior of a small
right valve. This is probably a juvenile shell of Semele ashleyi n. sp. P. 299

Semele ashleyi n. sp. Holotype (Los Angeles County Museum), from the same locality as
the specimen shown in fig. 1. Length 40.5 mm.; height 37 mm. View of the exterior of the
left valve. P.299

Semele ashleyi n. sp. Holotype. View of the exterior of the right valve of the specimen
shown in fig. 5.

Semele rubropicta Dall. View of the dorsal area of the specimen shown in figs. 1 and 2. This
view shows the small lunula-like area just anterior to the beaks. P. 300

Semele species. View of the interior of the specimen shown in fig. 4.

Semele ashleyi n. sp. View of the interior of the specimen shown in fig. 5.

. Semele ashleyi n. sp. View of the interior of the specimen shown in fig. 6.
. Semele rubropicta Dall. Hypotype (Los Angeles County Museum), from Loc. 318 (LAM),

Knox Ranch hill, just above the gates and cow shed; 200 feet from the road and 30 feet above
the valley floor, southwestern San Diego Co. Length 45.4 mm.; height 37.6 mm. View of the
interior of a right valve. P. 300

_ Solen rosaceus Carpenter. Hypotype (Cat. No. 5006, San Diego Society of Natural History),

from Mount Soledad, San Diego. Length 29.0 mm.; height 8.0 mm. View of the exterior of a
right valve. P.308

_ Gobraeus edentulus Gabb. Hypotype (University of California at Los Angeles), from Loc.

2359 (UCLA), sandstone outcropping in a small canyon parallel to and about 0.2 mile west
of the mouth of Rose Canyon and 0.4 mile north of Garnet Avenue, La Jolla quad., San
Diego. Length 82.8 mm.; height 41 mm. View of the exterior of a right valve. P. 305

_ Pandora (Pandorella) bilirata Conrad. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 3. Length 13.0 mm.; height 7.5 mm. View of the
exterior of a right valve. P.335

. Gobraeus edentulus Gabb. Hypotype (University of California at Los Angeles), from the

same locality as the specimen shown in fig. 13. Length 80.5 mm.; height 41 mm. View of the
exterior of a left valve. P.305

. Donax (Serrula) gouldii Dall. Hypotype (University of California at Los Angeles), from Loc.

294 (UCLA), 200 feet north of the Mexican boundary and %4 mile east of the coast; exposure
of strata in east-west ravine, tributary to a larger south-north ravine at right angle, in first
terrace above the Tiajuana River plain. Length 14.5 mm.; height 8.7 mm. View of the
exterior of a right valve. P.303

. Pandora (Pandorella) bilirata Conrad. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 3. Length 13.0 mm.; height 8.0 mm. View of the
exterior of a left valve. P.335

Pandora (Pandorella) bilirata Conrad. View of the interior of the specimen shown in fig. 17.
Donax (Serrula) gouldii Dall. Hypotype (Los Angeles County Museum), from Loc. 319
(LAM), exactly between the United States-Mexico boundary fence and Mr. Ericson’s (the
manager's) house; 27 feet above the road level on the shoulder of the second hill. Length 14
mm.; height 9.8 mm. View of the interior of a right valve. P.303

PLATE 48

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.
Fig. 5.

Fig. 6.

Fig. 7.

Fig. 8.

PLATE 49

Chione (Securella) kanakoffi n. sp. Paratype (Los Angeles County Museum), from Loc. 305
(LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19S., R. 2 W.,
San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length (of portion shown) approximately 97 mm. View of the hinge area of a left
valve. P.279

Siliqua lucida Conrad. Hypotype (San Diego Society of Natural History), from Loc. 43 (SD),
Reynard Way, San Diego. Length 38.2 mm.; height 16 mm. View of the exterior of a left
valve. P. 311

Chione (Securella) kanakoffi n. sp. Holotype (Los Angeles County Museum), from Loc. 305C
(LAM), exposure at base of hill, 100 feet west and 440 feet south of the northeast corner of
Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog.
map, San Ysidro quad., revision 1953). Length 129 mm.; height 122 mm. View of the
exterior of the right valve. P. 274

Chione (Securella) kanakoffi n. sp. View of the dorsal area of the specimen shown in figs. 3
and 5.

Chione (Securella) kanakoffi n. sp. View of the exterior of the left valve of the specimen
shown in figs. 3 and 4.

Chione (Securella) kanakoffi n. sp. Paratype (Los Angeles County Museum), from same
locality as the specimen shown in fig. 3. Length 131 mm.; height 117 mm. View of the
interior of a right valve. P. 274

Solen sicarius Gould. Hypotype (Cat. No. 5005, San Diego Society of Natural History),
gulch No. 4, south slope of Mount Soledad, San Diego. Length 63 mm.; height 16 mm. View
of a left valve.

Dosinia (Dosinia) ponderosa diegoana n. subsp. Paratype (California Academy of Sciences),
from Loc. 1402 (CAS), on end of point between Cabrillo Canyon and a gulch about 100
meters south of the west end of Laurel Street bridge, across Cabrillo canyon, Balboa Park,
San Diego. Length of area shown approximately 81.5 mm. View of the hinge area of a right
valve. P. 265

PLATE 49

Fig.
Fig.

Fig.
Fig.

Fig.

Fig.
Fig.
Fig.
Fig.

Fig.
Fig.

10.

PLATE 50

Megapitaria squalida Sowerby. Hypotype (Los Angeles County Museum), from Loe. 302
(LAM), exposure of strata across the street from the house at 2840 Columbia Street, San
Diego. Length 38.3 mm.; height 29.6 mm. View of the interior of a left valve. P. 268
Megapitaria squalida Sowerby. From the same locality as the specimen shown in fig. 1.
Length 46.2 mm.; height 35.5 mm. View of the exterior of a right valve. P. 268

Megapitaria squalida Sowerby. View of the interior of the specimen shown in fig. 2.

Tivela (Pachydesma) stultorum Mawe. Hypotype (University of California at Los Angeles),
from Loc. 312 (UCLA), second ravine north of Loc. L-294 (UCLA) and fifth ravine north
(about 4 mile) of the Mexican boundary, at west face of a terrace *4 mile from the coast.
Length 48 mm.; height 35 mm. View of the interior of a right valve. P. 266

Tivela (Pachydesma) stultorum Mawe. Hypotype (Los Angeles County Museum), from Loc.
305C (LAM), exposure at base of hill, 100 feet west and 440 feet south of the northeast
corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey
topog. map, San Ysidro quad., revision 1953). Length 96.8 mm.; height 73 mm. View of the
exterior of a left valve. P. 266

Tivela (Pachydesma) stultorum Mawe. View of the interior of the specimen shown in fig. 5.
Macoma (Revithaerus) indentata tenuirostris Dall. Hypotype (San Diego Society of Natural
History, from Loc. 331 (SD), 200 feet north of the Mexican boundary and %4 mile from the
coast, an exposure of strata of Pliocene age in an east-west ravine tributary to a larger
south-north ravine at right angle, in first terrace above the Tiajuana River plain. Length
27.3 mm.; height 16.3 mm. View of the exterior of a left valve. P. 297

Saridomus nuttalli latus Stewart. Hypotype (California Academy of Sciences), from Loc.
12051 (H. Hemphill Coll.), from San Diego well. Length (incomplete) 118 mm.; height
(incomplete) 79 mm. View of the interior of a right valve. P.272

Saxidomus nuttalli Conrad. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 4. Length 97.5 mm.; height 75.5 mm. View of the
exterior of a left valve.

Saxidomus nuttalli latus Stewart. View of the exterior of the specimen shown in fig. 8.

_ Irusella lamellifera Conrad. Hypotype (University of California at Los Angeles), from Loc.

298 (UCLA), lowest Pecten healeyi bed, from just south of a ravine which is immediately
south of the contact between the Hocene and the Pliocene strata, Pacific Beach. Length 27.4
mm. View of the exterior of a right valve, the apical area incomplete. P. 279

PLATE 50

Fig. 3.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

tH

Fig.

Fig.

Fig.
Fig.

eli hte2

16.

PLATE 51

Protothaca (Callithaca) tenerrima Carpenter. Hypotype (Los Angeles County Museum),
from Loc. 305A (LAM), west side of gully next east of Loc. 305 (LAM), at the same
elevation. Length of dorsal portion of the specimen, 56 mm. P. 277

Protothaca (Callithaca) tenerrima Carpenter. Hypotype (Los Angeles County Museum),
from Loc. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T.
19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San
Ysidro quad., ed. 1943). Length 49.4 mm.; height 37 mm. View of the interior of a left valve.
1897/7)

Protothaca (Callithaca) tenerrima Carpenter. Hypotype (California Academy of Sciences),
from Loe. 1402 (CAS), on end of point between Cabrillo Canyon and a gulch about 100
meters south of the west end of Laurel Street bridge across Cabrillo Canyon, Balboa Park,
San Diego. Length of portion of specimen, approximately 98.0 mm. View of the hinge area
of aright valve. P. 277

Chione (Securella) kanakoffi n. sp. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 17.7 mm.; height 18 mm. View of the
exterior of a juvenile left valve.

Chione (Securella) kanakoffi n. sp. Paratype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 19 mm.; height 16.5 mm. View of the
exterior of a juvenile right valve. P. 274

Chione (Securella) kanakoffi n. sp. View of the interior of the specimen shown in fig. 4.
Chione (Securella) kanakoffi n. sp. View of the interior of the specimen shown in fig. 5.
Psephidia ovalis Dall. Hypotype (Los Angeles County Museum), from Loc. 305C (LAM),
exposure at base of hill 100 feet west and 440 feet south of the northeast corner of Sec. 8, T.
19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San
Ysidro quad., revision 1953). Length 4.1 mm.; height 3.1 mm. View of the interior of the
right valve shown on plate 47, fig. 9. P. 280

Psephidia ovalis Dall. Hypotype ((Los Angeles County Museum), from the same locality as
the specimen shown in fig. 8. Length 4.2 mm.; height 3 mm. View of the interior of the left
valve shown on plate 47, fig. 5.

. Chione (Securella) kanakoffi n. sp. Paratype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 2. Length 131 mm.; height 117 mm. View of the
exterior of the specimen shown on plate 49, fig. 6.

. Chione (Chione) allisoni n. sp. Paratype (San Diego Society of Natural History), from Loc.

223 (SDSC), shell bed at base of cut and about 5 feet stratigraphically lower than Loc. 222
(SDSC). Length 27.5 mm.; height 25.8 mm. View of the exterior of a left valve showing the
comparatively fine radial ribbing and close concentric lamellae. P. 273

. Chione (Chione) allisoni n. sp. Paratype (San Diego Society of Natural History), from the

same locality as the specimen shown in fig. 11. Length 27.5 mm.; height 25.2 mm. View of
the interior of a right valve.

. Chione (Chione) allisoni n. sp. View of the exterior of the specimen shown in fig. 12.
. Dosinia (Dosinia) ponderosa diegoana n. subsp. Paratype (Los Angeles County Museum),

from the same locality as the specimen shown in fig. 2. Length 117 mm.; height 119 mm.
View of the exterior of the right valve of the specimen shown on plate 47, fig. 6, which has
been bored by a gastropod.

. Chione (Chione) allisoni n. sp. Holotype (San Diego Society of Natural History), from Loc.

222 (SDSC), shell bed exposed at middle of south facing cut bank on corner lot at northeast
corner of intersection of unnamed new streets, one of which is west of and parallel to Mount
Soledad Road, the other (dead end) extends east of the first and is one block north of Kate
Sessions Elementary School, San Diego. Length 32.6 mm.; height 27.2 mm. View of the
exterior of a left valve. P. 273

Chione (Chione) allisoni n. sp. View of the interior of the specimen shown in fig. 15.

PLATE 51

Fig.

Fig. :

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig. 9.

Fig.

Fig.

Fig.

Fig.

Fig.

bo

14.

PLATE 52

Macoma (Macoma) inquinata Deshayes. Hypotype (Los Angeles County Museum), from
Loc. 124 (LAM), shell and echini stratum 15 feet below level of floor of Snyder's
Continuation School. Length 33.3 mm.; height 25 mm. View of the interior of a left valve.
Pa292

Macoma (Rexithaerus) indentata tenuirostris Dall. Hypotype (Los Angeles County Mu-
seum), from Loe. 305A (LAM), west side of next gully east of Loc. 305 (LAM) at the same
elevation. Length 41.8 mm.; height 24.5 mm. View of the exterior of a right valve. P. 297
Macoma (Rexithaerus) indentata Carpenter. Hypotype (Los Angeles County Museum),
from Loc. 319 (LAM), exactly between the United States-Mexico boundary fence and Mr.
Ericson’s (the manager’s) house, 27 feet above the road level on the shoulder of the second
hill. Length 46 mm.; height 31 mm. View of the exterior of a right valve.

Macoma (Rexithaerus) indentata Carpenter. Hypotype (Los Angeles County Museum),
from Loe. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T.
19 S., R. 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San
Ysidro quad., ed. 1943). Length 35.5 mm.; height 23.6 mm. View of the exterior of a right
valve. P. 296

Macoma (Macoma) nasuta kelseyi Dall. Hypotype (Cat. No. 5679 San Diego Society of
Natural History), from Cholla Valley, San Diego. Length 86 mm.; height 61 mm. View of
the interior of a left valve. P. 294

Macoma (Macoploma) medioamericana Pilsbry and Olsson. Hypotype (Los Angeles County
Museum), from the same locality as the specimen shown in fig. 2. Length 60.4 mm.; height
34 mm. View of the exterior of a left valve. P. 295

Macoma (Rexithaerus) indentata Carpenter. View of the interior of the specimen shown in
fig. 4.

Macoma (Macoploma) medioamericana Pilsbry and Olsson. View of the interior of the
specimen shown in fig. 6.

Macoma (Macoma) nasuta kelseyi Dall. Hypotype (San Diego Society of Natural History),
from the same locality as the specimen shown in fig. 5. Length 85.8 mm.; height 58 mm.
View of the interior of a right valve. Note the difference in the shape of the pallial sinus
shown in this valve as compared to that in the left valve in fig. 5. P. 294

. Macoma (Macoma) inquinata Deshayes. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length 44 mm.,; height 32.8 mm. View of the
exterior of a right valve. P. 292

. Macoma (Macoma) nasuta kelseyi Dall. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length 84 mm.; height 60.5 mm. View of the
exterior of a left valve. P. 294

. Macoma (Macoma) nasuta kelseyi Dall. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length 107 mm.; height 77 mm. View of the
exterior of a right valve. P. 294

3. Protothaca (Callithaca) tenerrima Carpenter. Hypotype (Los Angeles County Museum),

from Loe. 305C (LAM), exposure at the base of a hill 100 feet west and 440 feet south of the
northeast corner of Sec. 8, T. 19 S., R. 2 W., San Bernardino Base and Meridian (see U.S.
Geol. Surv. topog. map, San Ysidro quad., revision 1953). Length 126 mm.; height 92.5 mm.
View of the exterior of a left valve. P. 277

Protothaca (Callithaca) tenerrima Carpenter. View of the interior of the dorsal area of the
specimen shown in fig. 13.

PLATE 52

Fig.

Fig. 2

Fig. ¢

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.

Fig. 18.

Fig.

Fig.
Fig.
Fig.
Fig.

Fig.

ule

~)

PLATE 53

Tellina (Moerella) carpenteri Dall. Hypotype (Los Angeles County Museum), from Loc.
305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T.195S., R. 2
W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1953). Length of area shown, approximately 9 mm.

Tellina (Cadella) salmonea Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length of area shown approximately 5.0 mm.
View of the hinge area of a left valve. P. 286

Tellina (Cadella) salmonea Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 9.2 mm.; height 6.4 mm. View of the
exterior of a right valve. P. 286

Tellina (Cadella) salmonea Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 8.0 mm.; height 5.9 mm. View of the
exterior of a left valve.

Macoma (Macoma) elimata Dunnill and Coan. Hypotype (University of California at Los
Angeles), from Loc. 2359 (UCLA), sandstone outcropping in a small canyon parallel to and
about two tenths of a mile west of the mouth of Rose Canyon and 0.4 mile north of Garnet
Avenue, La Jolla quad. Length 27.7 mm.; height 27.8 mm. View of the exterior of a right
valve. P. 291

Tellina (Tellinella) idae Dall. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 57.3 mm.; height 33.5 mm. View of the
exterior of a right valve. P. 285

Tellina (Moerella) carpenteri Dall. Hypotype (Los Angeles County Museum), from Loe.
305A (LAM), west side of next gully east of Loc. 305 (LAM), at the same elevation. Length
16.0 mm.; height 9.0 mm. View of the exterior of a right valve. P. 288

Tellina (Cadella) salmonea Carpenter. View of the hinge area of the specimen shown in fig.
3

Tellina (Peronidia) bodegensis Hinds. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 7. Length 51.8 mm.; height 25.5 mm. View of the
exterior of a left valve. P. 289

. Macoma (Macoma) nasuta Conrad. Hypotype (California Academy of Sciences), from Loc.

1178 (CAS), bluff at foot of Garnet Avenue, Pacific Beach. Length 30 mm.; height 21.38 mm.
View of the exterior of a right valve. P. 293

. Tellina (Tellinella) idae Dall. View of the interior of the specimen shown in fig. 6.
. Macoma (Macoma) acolasta Dall. Hypotype (University of California at Los Angeles), from

Loc. 1386 (UCLA), Dosinia beds in cut bank 338 feet farther along the ravine road (from
Loc. 1385) and just below the southeast corner of the Federal Building, Balboa Park, San
Diego. Length 25.6 mm.; height 15.4 mm. View of the exterior of a right valve. P. 290
Macoma (Macoma) acolasta Dall. View of the exterior of the left valve of the specimen
shown in fig. 12.

. Florimetis biangulata Carpenter. Hypotype (University of California at Los Angeles), from

Loe. 312 (UCLA), second ravine north of Loc. 294 (UCLA) and fifth ravine north (about
mile) of the Mexican boundary at west face of a terrace 4 mile east of the coast. Length 108
mm.; height 83.5 mm. View of the exterior of a right valve. P. 298

5. Tellina(Moerella)carpenteri Dall. Hypotype(Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1.

: Tellina (Cadella) salmonea Carpenter. View of the interior of the specimen shown in fig. 3.
. Florimetis biangulata Carpenter. View of the interior of the specimen shown in fig. 14.
. Tellina (Peronidia) bodegensis Hinds. Hypotype (University of California at Los Angeles),

from the same locality as the specimen shown in fig. 14. Length 38 mm.; height 28.4 mm.
View of the exterior of a right valve. P. 289

. Florimetis biangulata Carpenter. Hypotype (University of California at Los Angeles), from

the same locality as the specimen shown in fig. 14. Length 64.4 mm.,; height 57.3 mm. View
of the exterior of a left valve. P. 298

PLATE 53

Fig.

Fig.

Fig.

Fig.

Fig. 5.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

ou

10.

12.

PLATE 54

Spisula (Mactromeris) hemphillii Dall. Hypotype (Los Angeles County Museum), from Loc.
305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19S., R. 2
W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad., ed. 1943). Length 112 mm.; height 87 mm. View of the exterior of a right valve. P. 315
Spisula (Mactromeris) hemphillii Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Portion (47 mm. long) of a left valve showing
hinge area.

Spisula (Mactromeris) hemphillii Dall. Hypotype (Los Angeles County Museum), from Loe.
305A (LAM), west side of next gully east of Loc. 305 (LAM) at the same elevation. Length
123.6 mm.; height 94 mm. View of the exterior of a left valve. P. 315

Spisula (Mactromeris) hemphillii Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 3. Portion (35.5 mm. long) of a right valve
showing the hinge area. P. 315

Spisula (Mactromeris) catilliformis Conrad. Hypotype (Los Angeles County Museum),
from Loc. 107 (LAM), 100-foot bluff with fossiliferous concretions in clay quarry at end of
Arroyo Drive, San Diego. Length 91.6 mm.; height 74 mm. View of the exterior of a right
valve. P.313

Macoma (Macoma) nasuta Conrad. Hypotype (California Academy of Sciences), from Loc.
1178 (CAS), bluff at foot of Diamond Street, Pacific Beach. Length 21.5 mm.; height 30 mm.
View of left valve of the specimen shown on plate 53, fig. 10. P. 293

Spisula (Mactromeris) catilliformis Conrad. Hypotype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 1. Length 124 mm.; height 102 mm.
Spisula (Mactromeris) ef. S. (M.) falcata Gould. Hypotype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 3. Length 18 mm.; height 11.6 mm.
View of the exterior of a juvenile left valve. P.314

Spisula (Mactromeris) hemphillii Dall. Hypotype (Cat. No. 2946, San Diego Society of
Natural History), Reynard Way, San Diego. Length 134.5 mm.; height 102 mm. View of the
exterior of a left valve. P.315

Cryptomya californica magna Dall. Hypotype (California Academy of Sciences), from Loc.
1402 (CAS), on end of point between Cabrillo Canyon and a gulch about 100 meters south of
the west end of Laurel Street bridge across Cabrillo Canyon in Balboa Park, San Diego.
View of chondrophore of a left valve. Area illustrated approximately 20 mm. long. P.320

_ Tresus nuttallii Conrad. View of the interior of the juvenile specimen shown on plate

55, fig. 9.

Spisula (Mactromeris) mercedensis Packard. Hypotype (Los Angeles County Museum),
from the same locality as the specimen shown in fig. 5. Length 136 mm.; height 93 mm.
View of a left valve.

. Cryptomya californica magna Dall. Hypotype (California Academy of Sciences), from the

same locality as the specimen shown in fig. 10. Length 49.5 mm.; height 35 mm. View of the
exterior of a left valve. P.320

PLATE 54

Fig. 2.
Fig.
Fig.
Fig.
Fig.

Fig.

Fig.

Fig.

Fig.
Fig.

Fig.
Fig.

Fig.
Fig.

Fig.

Fig.

or

17.

PLATE 55

Corbula luteola Carpenter. Hypotype (Los Angeles County Museum), from Loc. 305 (LAM),
2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W., San
Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro quad., ed.
1943). Length 7.8 mm.; height 5.0 mm. View of the exterior of a left valve. P.324

Corbula luteola Carpenter. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 8.1 mm.; height 5.6 mm. View of the
exterior of a right valve. P. 329

Cryptomya californica Conrad. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 16.4 mm.; height 12.2 mm. View of the
interior of asomewhat rostrate right valve. P. 319

Cryptomya californica Conrad. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 11.2 mm.; height 8.4 mm. View of the
exterior of a right valve. P. 319

Corbula luteola Carpenter. View of the interior of the specimen shown in fig. 1.

Corbula luteola Carpenter. Hypotype from the same locality as the specimen shown in fig.
1. Length 7.9 mm.; height 5.4 mm. View of the interior of a right valve.

Cryptomya californica Conrad. Hypotype (Los Angeles County Museum), from the same
locality as the specimen shown in fig. 1. Length 13.0 mm.; height (incomplete) 10.8 mm.
View of the exterior of a rounded left valve. P.319

Cryptomya californica magna Dall. Hypotype (California Academy of Sciences), from Loc.
1402 (CAS), on end of point between Cabrillo Canyon and a gulch about 100 meters south of
the west end of Laurel Street bridge across Cabrillo Canyon in Balboa Park, San Diego.
Length 44 mm.; height 31.5 mm. View of the exterior of a right valve and a portion of the
ventral margin of the opposite valve. P. 320

Tresus nuttallii Conrad. Hypotype (Los Angeles County Museum), from the same locality
as the specimen shown in fig. 1. Length 38 mm.; height 25 mm. View of the exterior of a
juvenile right valve. P.318

. Cryptomya californica Conrad. View of the exterior of the specimen shown in fig. 3.
. Diplodonta (Diplodonta) orbella Gould. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 1. Length (incomplete) 12.5 mm.; height 11.4
mm. View of the exterior of a somewhat elongated, juvenile left valve. P. 252

. Cryptomya californica magna Dall. View of the left valve of the specimen shown in fig. 8.
. Tresus nuttallii Conrad. Hypotype (University of California at Los Angeles), from Loc.

2420 (UCLA), bluffs along Pacific Beach about 2 mile southeast of False Point, La Jolla
quad. Length 104 mm.; height 73 mm. View of the exterior of a left valve. P.318

. Tresus nuttallii Conrad. View of the exterior of the right valve of the specimen shown in fig.

13.

. Corbula luteola Carpenter. View of the dorsal area of the specimen of which the right valve

is shown in fig. 6, the left valve in fig. 1.

. Cryptomya californica Conrad. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 1. Length 17.3 mm.; height 12.3 mm. View of the
exterior of a right valve. P.319
Tresus nuttallii Conrad. View of the dorsal area of the specimen shown in figs. 13, 14.

PLATE 55

Fig. 1.

Fig. 2.

Fig. 3.

Fig. 4.

Fig. 5.

Fig. 6.

Fig. 7.

PLATE 56

Miodontiscus prolongatus Carpenter. Hypotype (Los Angeles County Museum), from Loc.
323 (LAM), under bridge between Fifth Street and the Radio Station, about 160 feet from
the fence and about 350 feet from the Radio Station, San Diego. Length 6.7 mm.; height 7.8
mm. View of the exterior of a left valve. P.233

Miodontiscus prolongatus Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 4.9 mm.; height 5.9 mm. View of the
interior of a right valve. P. 233

Miodontiscus prolongatus Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 4.6 mm.; height 4.9 mm. View of this
interior of a left valve. P.233

Miodontiscus prolongatus Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 5.38 mm.; height 5.8 mm. View of the
exterior of a right valve. P. 233

Miodontiscus prolongatus Carpenter. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 1. Length 4.7 mm.; height 5.2 mm. View of the
exterior of a right valve. P. 233

Dermatomya tenuiconcha Dall. Hypotype (Los Angeles County Museum), from Loe. 305
(LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S., R. 2 W.,
San Bernardino Base and Meridian (see U.S. Geol. Survey topog. map, San Ysidro
quad. ed. 1943). Length 9.7 mm.; height 8.2 mm. View of the exterior of a right valve. P. 341
Dermatomya tenuiconcha Dall. View of the exterior of the left valve of the specimen shown
in fig. 6.

Penitella penita Conrad. Hypotype (San Diego Society of Natural History), from Loc. 417
(SD), second ravine north of Loe. 331 (SD) and fifth ravine north (about 4 mile) of the
Mexican boundary at west face of the terrace, about % mile from the coast. Length 52.3
mm.; height 28.5 mm. View of the exterior of a left valve. P. 333

Penitella penita Conrad. Hypotype (University of California at Los Angeles), from Loc. 312
(UCLA), same locality as the specimen shown in fig. 8. Length 51.4 mm.; height 29 mm.
View of the exterior of a right valve. P. 333

_ Dermatomya tenuiconcha Dall. View of the interior of the specimen shown in fig. 6.
_ Dermatomya tenuiconcha Dall. View of the interior of the specimen shown in fig. 7.
_ Panomya cf. P. beringiana Dall. Hypotype (California Academy of Sciences), from Loc.

1418 (CAS), northeast corner of India and Spruce streets, San Diego. Length 44 mm.; height
38 mm. View of the exterior of a cast of a left valve. P. 329

3. Dermatomya tenuiconcha Dall. Enlarged view of the hinge area of the specimen shown in

fig. 11.

_ Tellina (Moerella) carpenteri Dall. Hypotype (Los Angeles County Museum), from Loc.

305A (LAM), west side of next gully east of Loc. 305 (LAM), at the same elevation. Length
14.6 mm.; height 9.9 mm. View of the exterior of a left valve. P. 288

5. Hiatella arctica Linnaeus. Hypotype (Los Angeles County Museum), from the same locality

as the specimen shown in fig. 14. Length 5.6 mm.; height 1.3 mm. View of the exterior of a
juvenile left valve. P. 326

;. Penitella penita Conrad. View of the interior of the specimen shown in fig. 9.
_ Hiatella arctica Linnaeus. Hypotype (Los Angeles County Museum), from the same locality

as the specimen shown in fig. 14. Length 6.3 mm.; height 2.8 mm. View of the interior of a
left valve. P. 326

3. Hiatella arctica Linnaeus. View of the exterior of the specimen shown in fig. 17.

_ Panope generosa Gould. Hypotype (Los Angeles County Museum), from the same locality
as the specimen shown in fig. 14. Length 106 mm.; height 72 mm. View of the dorsal area. P.
328

. Panope generosa Gould. View of the exterior of the right valve of the specimen shown in fig.
19.

21. Sphenia ef. S. luticola Valenciennes. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 6. Length 3.8 mm.; height 2.7 mm. View of the
exterior of a left valve. P. 321

2. Spheniacf.S. luticola Valenciennes. View of the interior of the specimen shown in fig. 21.

PLATE 56

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.

Fig.
Fig.

Fig.

a

20

PLATE 57

Penitella penita Conrad. Hypotype (Los Angeles County Museum), from Loc. 107 (LAM),
clay quarry at end of Arroyo Drive, San Diego. Length 47.2 mm.; height 30.4 mm. Dorsal
view. P. 333

Penitella penita Conrad. Hypotype (Los Angeles County Museum), from the same locality
as the specimen shown in fig. 1. Length 44.4 mm.; height 25.9 mm. View of the exterior of a
right valve. P. 333

Corbula gibbiformis Grant and Gale. Hypotype (University of California at Los Angeles),
from Loe. 2359 (UCLA), in small canyon parallel to and about 0.2 mile west of the mouth of
Rose Canyon and 0.4 mile north of Garnet Avenue, La Jolla quad., San Diego. Length 14.9
mm.; height 14.6 mm. View of the interior of a right valve. P. 323

Corbula gibbiformis Grant and Gale. View of the exterior of the specimen shown in fig. 3.
Penitella conradi Valenciennes. Hypotype (Los Angeles County Museum), from Loc. 305C
(LAM), exposure at base of hill, 100 feet west and 440 feet south of the northeast corner of
Sec. 8, T. 19 S., R 2 W., San Bernardino Base and Meridian (see U.S. Geol. Survey topog.
map, San Ysidro quad., revision 1953). Length 25 mm.; height 20.3 mm. View of the exterior
of the left valve. P. 332

Basterotia (Basterotella) hertleini Durham. Hypotype (Los Angeles County Museum), from
the same locality as the specimen shown in fig. 5. Length 11 mm.; height 7.3 mm. View of
the interior of a right valve. P. 241

Ensis myrae Berry. Hypotype (Los Angeles County Museum), from Loc. 305A (LAM), west
side of next gully east of Loc. 305 (LAM), at the same elevation. Length (incomplete) 14
mm.; height 8.6 mm. View of the interior of the anterior end of a left valve. P. 309

Donax (Serrula) gouldii Dall. Hypotype (Los Angeles County Museum), from Loe. 319
(LAM), exactly between the United States-Mexico boundary fence and Mr. Ericson’s (the
manager's) house, 27 feet above the road level on the shoulder of the second hill. Length 21.2
mm.; height 10.9 mm. View of the exterior of a left valve. P. 303

Diplodonta (Diplodonta) orbella Gould. Hypotype (Los Angeles County Museum), from
Loe. 305 (LAM), 2400 feet east and 1350 feet south of the northwest corner of Sec. 8, T. 19 S.,
R. 2 W., San Bernardino Base and Meridian, southwestern San Diego Co. Length (approx-
imately) 18 mm.; height 17 mm. View of the exterior of a right valve, the posterior margin
incomplete. P. 252

. Lima (Limaria) orcutti Hertlein and Grant. Hypotype (Los Angeles County Museum), from

the same locality as the specimen shown in fig. 5. Length 35.8 mm.; height 44.8 mm. View of
the exterior of a right valve. P. 215

. Basterotia (Basterotella) hertleini Durham. View of the exterior of the specimen shown in

fig. 6.

2. Spisula (Mactromeris) ef. M. (M.) planulata Conrad. Hypotype (University of California at

Los Angeles), from Loc. 294 (UCLA), 200 feet north of Mexican boundary and %4 mile east of
the coast, exposure in east-west ravine tributary to a larger south-north ravine at right
angle, in first terrace above Tiajuana river plain. Length 31.7 mm.; height 25.3 mm. View of
the exterior of a right valve.

. Penitella conradi Valenciennes. Dorsal view of the specimen shown in fig. 5. P. 332
. Cuspidaria (Cardiomya) pectinata Carpenter. Hypotype (Los Angeles County Museum),

from the same locality as the specimen shown in fig. 7. Length 7 mm.; height 4.2 mm. View
of the exterior of a right valve. P. 342

5. Compsomyax subdiaphana Carpenter. Hypotype (Los Angeles County Museum), from the

same locality as the specimen shown in fig. 9. Length 32.7 mm.; height 26.4 mm. View of the
exterior of a right valve, umbonal portion incomplete. P. 269

. Spisula (Mactromeris) hemphillii Dall. Hypotype (Los Angeles County Museum), from the
same locality as the specimen shown in fig. 9. View of a portion of a right valve 54 mm. long,
showing the hinge. P. 315

7. Nuculana aff. N. leonina Dall. Hypotype (Los Angeles County Museum), from the same

locality as the specimen shown in fig. 9. Length 8.6 mm.; height 4.8 mm. View of the interior
of aright valve. P. 149

. Diplodonta (Diplodonta) orbella Gould. View of the interior of the specimen shown in fig. 9.

. Ensis myrae Berry. Hypotype (Los Angeles County Museum), from the same locality as the
specimen shown in fig. 7. Length 65.8 mm.; height 10.4 mm. View of the exterior of a right
valve embedded in sediment in the interior of a left valve of Spisula hemphillii Dall. P. 309

. Nuculana aff. N. leonina Dall. View of the exterior of the shell shown in fig. 17.

PLATE 57

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