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Tertiary Marine Pelecypods of 

California and Baja California: 

Erycinidae Through Carditidae

By ELLEN JAMES MOORE

PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1992
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director

Any use of trade, product, or firm names in this

publication is for descriptive purposes only and does not

imply endorsement by the U.S. Government

Library of Congress Catalog-in-Publication Data

Moore, Ellen James.

Tertiary marine pelecypods of California and Baja California: Erycinidae through Carditidae / by 

Ellen James Moore.

p. cm. (Paleontology of California and Baja California) 

(U.S. Geological Survey professional paper; 1228-E) 

Includes bibliographical references and index. 

Supt. of Docs, no.: I 19.16: 1228-E

1. Bivalvia, Fossil California. 2. Bivalvia, Fossil Mexico Baja California. 3. Paleontology California 

Mexico Baja California. I. Title. II. Series. III. Series: U.S. Geological Survey professional paper; 1228-E. 

QE811.M636 1992

564'.11'09794 dc20 92-3921

CIP

For sale by the Books and Open-File Reports Section, U.S. Geological Survey, 

Federal Center, Box 25286, Denver, CO 80225
CONTENTS

	Page 

Abstract - _____________......_........................... j] i

Introduction 1

Purpose and scope 1

Procedure - ----- ---«-«-«-«-- ---«-«- ------ «« - " ' --««--- 1

Acknowledgments 4

Abbreviations 4

Systematics: Pelecypods Continued from Chapter D 5

Family Erycinidae 5

Genus Lasaea 5

Family Kelliidae -- -- 6

Genus Kellia 6

Genus Aligena 7

Subgenus Aligena 7

Genus Bornia 8

Subgenus Temblornia 8

Family Montacutidae 9

Genus Mysella 9

Subgenus Rochefortia 9

Genus Thecodonta 9

Subgenus Pristes 9

Genus Neaeromya 9

Subgenus Orbitella 10

Family Sportellidae 10

Genus Basterotia W

Subgenus Basterotella W

Systematics: Pelecypods Continued from Chapter D 

Continued

Family Carditidae 

Genus Cardita 

Subgenus Cardita 

Subgenus Byssomera 

Genus Strophocardia 

Genus Cyclocardia 

Subgenus Cyclocardia 

Genus Glans 

Subgenus Glans 

Subgenus Centrocardita 

Genus Miodontiscus 

Subfamily Venericardinae 

Genus Venericardia 

Subgenus Paciftcor 

Subgenus Venericor 

Subfamily Carditesinae 

Genus Glyptoactis 

Subgenus Claibornicardia 

Subfamily Thecaliinae 

Genus Milneria 

Fossil localities 

Geologic formations cited for occurrence of pelecypods - 

References 

J.HQ6X -«-«--------«----- --- ----- - -- - " -----"- -" ----- ----- ------

Ell 

11 

11

11

12

12

12

15

15

15

16

16

16

16

25

26

26

26

28

28

28

29

30

35

ILLUSTRATIONS

PLATE 1.

2.

3.

4.

5.

6.

7.

8.

9.

FIGURE 1.

2.

3.

[Plates follow index]

Venericardia, Lasaea, Aligena, Kellia, Glyptoactis.

Venericardia.

Venericardia, Kellia, Bornia.

Venericardia, Thecodonta, Neaeromya, Cardita.

Venericardia, Glans, Miodontiscus.

Venericardia.

Cardita, Cyclocardia, Mysella, Glans, Glyptoactis, Cyclocardia.

Venericardia, Glyptoactis.

Cyclocardia, Venericardia, Basterotia, Cardita, Milneria.

Divisions used in California for geographic range of species of pelecypods, Erycinidae through Carditidae 

Divisions used in Baja California peninsula for geographic range of species of pelecypods, Erycinidae through

Carditidae 

Preliminary phylogenetic chart of Glyptoactis and Venericardia in the eastern Pacific prepared by LouElla Saul,

Los Angeles County Museum of Natural History. 

Page

E12

3

18

TABLES

TABLES 1-3. Geologic and geographic distribution in the eastern Pacific region of the genera:

1. Lasaea, Kellia, Aligena, Bornia, Mysella, Thecodonta, Neaeromya, Basterotia, Cardita, and Strophocardia

2. Cyclocardia, Glans, and Miodontiscus -

3. Venericardia, Glyptoactis, and Milneria - -- - -

Page

E5 

12 

17

III

PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

TERTIARY MARINE PELECYPODS OF CALIFORNIA AND BAJA CALIFORNIA:

ERYCINIDAE THROUGH CARDITIDAE

By ELLEN JAMES MOORE

ABSTRACT

The description of the mollusks in the Tertiary formations of 

California and Baja California is continued from Chapter D. 

Forty-eight species in the families Erycinidae, Kelliidae, 

Montacutidae, Sportellidae, and Carditidae, representing 15 genera, are covered in this chapter. Of the 15 included genera, 1 

occurs in the Cretaceous, 2 in the Paleocene, 3 in the Eocene, 1 

in the Oligocene, 3 in the Miocene, 11 in the Pliocene, 5 in the 

Pleistocene, and 12 in the Holocene of the included geographic 

area. Four genera are extinct or locally extinct.

Venericardia (Pacificor) taliaferroi Verastegui was found by 

Verastegui (1953) to occur in the Late Cretaceous lower part of 

the Dip Creek Formation of Taliafero (1944) of Late Cretaceous 

and Paleocene age, thus extending the range of the genus 

Venericardia and the subgenus Pacificor into the Late Cretaceous in the eastern Pacific.

INTRODUCTION 

PURPOSE AND SCOPE

The description and illustration of the Tertiary 

marine mollusks of California and Baja California 

started in Chapter A is continued in this chapter, 

which treats the families Erycinidae, Kelliidae, 

Montacutidae, Sportellidae, and Carditidae.

A total of 48 species assigned to the included 

families occur in the geographic study area. For convenience of reference, the figures showing the geographic divisions used for the Californias are 

reproduced here (figs. 1, 2).

PROCEDURE

All Tertiary marine mollusks originally described 

from California and the Baja California peninsula, 

and all species originally described from other

Manuscript approved for publication, September 24, 1991.

geographic localities but known to occur in the 

Tertiary of the Californias, are included in this 

study. All positively identified species that have been 

found on faunal lists are also included. Only in 

genera that are extremely rare have I included 

species that are questionably identified.

In this work, the species are arranged systematically following the order of families, genera, and subgenera given in the Treatise (Moore, 1969). Within 

the systematic groups, species are arranged by geologic age, beginning with the oldest species and ending with the youngest.

Brief synopses of generic and subgeneric characters are given in the appropriate places; more complete synopses will be found in the Treatise (Moore, 

1969), in Keen (1971), and in Olsson (1961).

Distribution tables are included to show graphically the geographic and geologic distribution of species within each family. To facilitate finding a 

specific taxon, the species are listed alphabetically 

under genus and subgenus in the tables.

The synonymy for each species includes the original citation and subsequent substantive references. 

The accuracy of identifications cited in subsequent 

references in the synonymy has not been verified.

The type is usually that of the author of the original 

description or of later workers who selected a lectotype 

or neotype. If the original locality description is so vague 

that it is of little use, the type locality is described as 

corrected or modified by other workers such as Keen 

and Bentson (1944) and the modifications given within 

brackets. All other localities are cited as originally described except the formation name given is that of the 

one currently being used.

Previously published supplementary descriptions 

and comparisons are included, and I have supplemented them in the section headed "Comments." For 

most descriptions, my comments are based only on 

examination of primary type material.

El
E2

125°

PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA 

120° 115°

42°

39°

34°

0 50 100 150 200 KILOMETERS 

I I I __I

SAN MATEO

O

SANTA CRUZ

VENTURA \ . .__ ..,,,,., ,-c Santa Cruz ^ \ LOS ANGELES

Island

San Miguel Island «^_ . 

Santa Rosa Island

San Nicolas Island | s | and 

San Clemente Island

FIGURE 1. Divisions used in California for geographic ranges of species of pelecypods, Erycinidae through Carditidae.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE

116° 114° 112° 110°

E3

32°

30°

28°

26°

24°

San Diego '

CALIFORNIA

7

7 ARIZONA

Ensenada

San Quintin 

Rosario

O Isla Carmen

Isla Monserrate 

O

Isla San Diego

Isla San Jose 

\ V

/^ Bahia 

Isla CedrosJ ) Sebastian

Isla de 0 

Natividad

Bahia 

Tortugas

O

O

O

o

Isla Magdalena

Bahia Magdalena

50 100

I

150 

I

200 KILOMETERS

Cabo San Lucas

FIGURE 2. Divisions used on Baja California Peninsula for geographic ranges of species of pelecypods,

Erycinidae through Carditidae.
E4 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

All available published data for each species have 

been included in the section on geographic and geologic age range, including that contained in faunal 

lists when the identification is unqualified. Age 

ranges have not been refined within epochs. Where a 

stage name the same as a formation name is used 

(see fig. 3), it is placed in quotes to distinguish it 

from the rock unit.

The divisions used here to indicate the approximate geographic range of species within California 

based on county distribution are northern, middle, 

and southern (fig. 1); the divisions for the Baja California Peninsula, norte and sur (fig. 2) (tables 1-3).

An attempt has been made to include all citations to a species that are unqualified and every 

geologic formation in which it is reported to occur 

in the Californias. The assumption has been made 

that all identifications of species are correct unless 

there is strong evidence to the contrary. Under 

"Occurrence," the author cited for a formation is 

the individual who named or cited the species and 

not the author who mapped or named the formation. The stratigraphic nomenclature used herein is 

that of the author(s) cited and does not necessarily 

agree with that of the U.S. Geological Survey. The 

ages given for the stratigraphic units follow the 

classification of geologic time currently used by the 

U.S. Geological Survey (See "Geologic Formations 

Cited for Occurrence of Pelecypods" at end of paper), which does not necessarily agree with the the 

most recent revisions by workers outside the Survey. Each formation listed is followed by the name 

of the author and date of publication of the work 

from which it was obtained. More than one reference to a formation is given where it might be useful to the reader. The list of formations given for 

species occurrence should not be considered complete nor necessarily accurate. Many western 

American Tertiary faunas have not been included 

in a monograph, therefore, their species content is 

not fully known. It is hoped that the list of formational occurrences reported will serve as a framework upon which the true distribution of each 

species can be built.

The type specimens were all photographed by 

Charles L. Powell, II, of the U.S. Geological Survey. 

Owing to the fact that the specimens photographed 

were borrowed from other institutions, the usual 

technique of opaquing specimens for photography 

(Sakamoto, 1973) was not used. The holotype of each 

Tertiary species is figured if the type is extant. Holocene type specimens have generally not been figured; 

specimens considered to be of the same species by 

authors such as Durham (1950) and Hertlein and

Grant (1972) are used for these illustrations, and 

this information is included in the plate explanation. 

Most of the data on habitat has been compiled 

from Abbott (1974), Bernard (1983), Hertlein and 

Grant (1972), Keen (1971), Morris and others (1980), 

Smith and Gordon (1948), Stanley (1970), and Yonge 

and Thompson (1976).

ACKNOWLEDGMENTS

John G. Vedder, of the U.S. Geological Survey, 

reviewed the stratigraphic occurrences of species, 

and his pertinent suggestions were most helpful. 

LouElla Saul, Los Angeles County Museum of Natural History, reviewed the section on Venericardia, 

and Eugene Coan, Palo Alto, Calif., reviewed the 

section on Cardita and Cyclocardia; I am grateful 

for their generous assistance. LouElla Saul also generously allowed me to publish her preliminary phylogenetic chart of Glyptoactis and Venericardia, and 

I am indebted to her for this kindness.

The following individuals made available or 

loaned type material, and I am indebted to them: 

Elana Benamy, Academy of Natural Sciences of 

Philadelphia, Frederick J. Collier and Jann W.M. 

Thompson, National Museum of Natural History, 

Thomas A. Demere, San Diego Natural History Museum, David R. Lindberg, University of California 

Museum of Paleontology, Robert Van Syoc, California Acadamy of Sciences, and Edward C. Wilson, Los 

Angeles County Museum of Natural History.

The late Mildred P. James made up cards for each 

species and its occurrences as noted on faunal lists. 

This was a time consuming task that she performed 

as a volunteer, and I am grateful to her for her patience and support.

ABBREVIATIONS

ANSP: The Academy of Natural Sciences of Philadelphia, Pennyslvania.

BM(NH): British Museum of Natural History, London, England.

CAS: California Academy of Sciences, San Francisco, 

Calif.

CASG: California Academy of Sciences Geology, San 

Francisco, Calif.

LACMP: Los Angeles County Museum of Paleontology, California.

LAM: Los Angeles County Museum of Natural History, California.

MCZ: Harvard Museum of Comparative Zoology, 

Cambridge, Mass.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E5

TABLE 1. Geologic and geographic distribution of the genera Lasaea, Kellia, Aligena, Bornia, Mysella, Thecodonta, Neaeromya,

Basterotia, Cardita, and Strophocardia in the eastern Pacific Region

[H=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; E=Eocene; Pa=Paleocene]

Species Alaska British 

Columbia

Washington

Oregon California

Northern Middle Southern

Baja California

Norte Sur

Central 

or South 

America

Genus Lasaea^

subviridisDa31........... ......................

Genus Kellia

catacta Anderson and G D. Hanna 

lajollaensis M.A. Hanna.................

laperousii (Deshayes)....................

uvasana (Dickerson)......................

Genus Aligena 

Subgenus Aligena

diegoana Hertlein and Grant..........

Genus Bornia

Subgenus Temblomia 

frankiana Hertlein and Grant.........

triangulata (Anderson and Martin) 

Genus Mysella

Subgenus Rochefortia

tumida (Carpenter).........................

Genus Thecodonta 

Subgenus Pristes

oblongus (Carpenter).....................

Genus Neaeromya 

Subgenus Orbitella

compressa (Dall)............................

Genus Basterotia

Subgenus Basterotella

hertleini Durham............................

Genus Cardita 

Subgenus Cardita

superiors Waring...........................

Subgenus Byssomera

affinis Sowerby...............................

Genus Strophocardia

megastropha (Gray).......................

MtoH H

E

E

PltoH Pie to H 

PatoE

H

H 

M

H PletoH PltoH PletoH H

H PltoH H

H PI to H H

PltoH

PltoH 

PltoH

H 

Pie to H

CAS/SU: Stanford University, Stanford, Calif. 

[Stanford University collections are now in the 

California Academy of Sciences]

SU: Stanford University, Stanford, Calif.

UC: University of California, Berkeley.

UCMP: University of California, Museum of Paleontology, Berkeley.

UCLA/LACMP: University of California at Los Angeles. [University of California at Los Angeles type 

collections are now in the Los Angeles County 

Museum of Paleontology]

UCR: University of California at Riverside.

USGS: U.S. Geological Survey, Washington, B.C., 

Cenozoic locality register.

USGS M: U.S. Geological Survey, Menlo Park, Calif., 

Cenozoic locality register.

USNM: National Museum of Natural History, Washington, B.C. 

UW: University of Washington, Seattle.

SYSTEMATICS: PELECYPODS CONTINUED 

FROM CHAPTER D

Family ERYCINIDAE 

Genus LASAEA Brown, 1927

Transversely rounded, minute, inflated, inequilateral, smooth, 

anterior side longest, beaks straight.

Geographic range. Worldwide.

Geologic range. Eocene to Holocene (table 1).

Habitat. Intertidal, especially among Mytilus (Keen, 1971); 

intertidal to 10 m in the eastern Pacific (Bernard, 1983).
E6 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Lasaea subviridis Dall, 1899 

Plate 1, figures 2, 4

Lasaea rubra subviridis Dall, 1899, p. 881 [ex Carpenter MS]. 

Lasaea subviridis Dall, 1899. Keen, 1938, p. 29-30, pi. 2, figs. 1-6. 

Keen, 1971, p. 137, fig. 311.

Original description. U[L. rubra] variety subviridis Carpenter, is pale greenish yellow. It is reported from Lower California."

Neotype. CAS/SU 6053; CASG 65100 (Keen, 1938); syntypes 

USNM 75032. Coan (1977) believed the neotype designation of 

Keen (1938) to be invalid because Dall's material was never 

properly searched.

Type locality. "Lower California" (Dall, 1899); Isla San Martin, Baja California Norte (Keen, 1938); Bahia San Quintin, 

Baja California Norte (Coan, 1987). Holocene.

Supplementary description. "Shell minute, inequilateral (anterior end longer), oblique, rather flat, greatest dimension parallel to postero-dorsal margin, but not parallel to a line joining 

muscle-scars, beaks at posterior 2/5, umbones low (usually less 

than 1/10 the height of the shell); junction of anterior and ventral margins somewhat attenuated, ventral margin rounded, 

joining posterior in a smooth curve; colour greenish or yellowish 

grey, suffused with pink at the beaks, the colour sometimes extending down into the ventral half of the shell, hinge tinged 

with pink; surface sculptured by irregular growth-constrictions 

and minute, wavy concentric striae, especially near the ventral 

margins; hinge of right valve with a lamellar (sometimes bifid) 

anterior lateral and nymph, a deep cardinal pit, and a lamellar 

posterior cardinal above the long, oblique resilium, hinge of left 

valve with two lamellar anterior laterals receiving the single 

lateral of the right valve, a thorn-like cardinal, and a small lamellar posterior lateral." (Keen, 1938)

Comparison. "Lasaea subviridis is distinguished from L. 

rubra by its greater size and the presence in the adult of wavy 

concentric sculpture, from Western Pacific species such as 

purpurata and scalaris by the wrinkling rather than pitting of 

the sculpture, and from L. cistula by its more oblique outline, 

its light colour, less tumid and lower umbones, and by the 

smooth slope of the anterior margin downward from the beaks. 

In dimensions, young specimens***are consistently longer than 

cistula of the same height; the height-length ratio of young 

subviridis is very similar to that of adult L. rubra." (Keen, 

1938)

Geographic range. Living: Northern California to Baja California Sur; fossil: southern California.

Geologic range. Miocene and Pliocene.

Occurrence in California. Miocene and Pliocene: Capistrano 

Formation (Kern and Wicander, 1974).

Habitat. Among the byssi of Mytilus along the uppermost 

edge of the mussel colonies (Keen, 1936); in kelp holdfasts 

(Smith and Gordon, 1948); intertidal to 10 m (Bernard, 1983).

Family KELLIIDAE 

Genus KELLIA Turton, 1822

Ovate, slightly angular and strongly convex, with concentric 

striation.

Geographic range. Worldwide.

Geologic range. Eocene to Holocene (table 1).

Habitat. Intertidal to 50 m in the eastern Pacific (Bernard, 

1983); often nestles in holes in rock (Hertlein and Grant, 1972).

Kellia catacta Anderson and GD. Hanna 

Plate 1, figure 7

Corbula harrisi Dickerson, 1915, p. 42, 56, pi. 4, fig. 6.

Dickerson, 1916, p. 420, 445.

Kellia catacta Anderson and GD. Hanna, 1925, p. 171, pi. 2, fig. 6. 

New name for Corbula harrisi Dickerson not Corbula (Cuneocorbula) swiftiana harrisi Dall, 1898.

Original description. "Shell small, thick, subtrigonal, with 

beak central, slightly prosogyrate; anterior dorsal slope slightly 

steeper than the moderately steep posterior dorsal slope; base 

broadly rounded; posterior end sharply rounded; a faint umbonal 

slope extending to the point between the posterior end and the 

base; shell decorated by faint radial ribbing which is strongest at 

posterior end along the umbonal slope and by concentric growth 

lines. Interior of shell is unknown and hence generic reference is 

doubtful. This species is not so thick as C. parilis Gabb and its 

concentric ribbing is not so strong."

Holotype. GAS 275.

Type locality. GAS 244. Kern County, Calif. Tejon Formation, 

Eocene.

Geographic range. Southern California.

Geologic range. Eocene (table 1).

Occurrence in California. Eocene: Tejon Formation 

(Dickerson, 1915).

Kellia uvasana (Dickerson) 

Plate 3, figures 9, 12

Corbula uvasana Dickerson, 1915, p. 42, 46, pi. 4, fig. 7.

Dickerson, 1916, p. 420, 445.

Kellia uvasana (Dickerson). Anderson and GD. Hanna, 1925, 

p. 172, pi. 2, fig. 7; pi. 9, fig. 11.

Original description. "Shell small, inflated with central beak, 

anterior dorsal margins slightly concave with moderate slope to 

a subtruncate anterior end; posterior dorsal margin with slight 

slope to a broadly rounded posterior; ventral margin broadly 

rounded. Faint radial lines and feeble concentric growth lines 

decorate this shell. Interior unknown.

"Dimensions: Length, 7 mm.; height, 5 mm.; convexity, 

2 mm."

Holotype. GAS 276; CASG 244.04.

Type locality. GAS 244. Kern County, Calif. Tejon Formation, 

Eocene.

Supplementary description. "The shell is small, thin, elliptical; surface smooth, except for small radial ridges extending 

from the umbones to the margins near the anterior and posterior 

ends, forming small marginal denticulations within." (Anderson 

and Hanna, 1925, p. 172)

Geographic range. Southern California.

Geologic range. Paleocene to Eocene (table 1).

Occurrence in California. Paleocene: Cerros Shale Member of 

Lodo Formation (Dickerson, 1916); Eocene: Tejon Formation 

(Dickerson, 1915).

Kellia lajollaensis M.A. Hanna 

Plate 3, figure 8

Kellia lajollaensis M.A. Hanna, 1927, p. 284, pi. 37, fig. 7.

Original description. "Shell small, well inflated, subquadrate; 

ventral margin straight; posterior margin rounded to slightly 

truncated; anterior margin rounded; beak prominent, rounded,
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E7

nearly central; dorsal slopes on either side of the beak straight; 

surface ornamented on the posterior and anterior by rather 

prominent well-rounded ribs which are separated by concave 

interspaces of less width; concentric ornamentation consists of 

wide flat-topped ridges marked off by narrow lines; these concentric ridges distinctly overlap each other with the overlap toward 

the margin and not toward the beak; this overlap shows very 

well where the concentric ridges cross the radial ones, the concentric lines bend toward the beak in crossing the radial ridges; 

no radial sculpturing present in the central portion of the shell; 

interior of the type not seen. Dimensions: Altitude 4.5 mm., 

length 6.5 mm., dorsal angle 117 degrees."

Holotype. UCMP 31036.

Type locality. UC 3991. San Diego County, Calif. Rose Canyon Shale of Hanna (1927), Eocene.

Comparison. "Kellia lajollaensis***most closely resembles 

Kellia catacta Anderson and Hanna, described by Dickerson as 

Corbula harrisi. However, Kellia lajollaensis has a different 

shape. The dorsal angle is greater and the ventral margin is 

straight. The new species differs much in sculpturing from either Kellia catacta or Kellia uvasana (Dickerson). The radial 

ridges on either extremity are more prominent, and the concentric sculpturing is different." (Hanna, 1927)

Geographic range. Southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: Rose Canyon Shale (M.A. 

Hanna, 1927).

Kellia laperousii (Deshayes) 

Plate 3, Figures 10, 15

Chironia laperousii Deshayes, 1839, p. 357.

Kellia laperousii (Deshayes). Arnold, 1903, p. 137, pi. 18, figs. 1, 

la. Oldroyd, 1924, p. 131, pi. 10, fig. 2; pi. 33, fig. 4. Yonge, 

1951, p. 451-453, text fig. 1. Hertlein and Grant, 1972, p. 237, 

pi. 44, figs. 11, 19.

Chironia suborbicularis (Montagu) variety laperousii Deshayes. 

Grant and Gale, 1931, p. 300, pi. 14, figs. 19a, 19b.

Original description. "Testa ovato transversa, 

subequilaterali, inflato turgida, laevigata; alba sub-epidermide 

viridi lutescente, umbonibus minimis, acutis, oppositis."

Holotype. In the collection of the Laboratoire de Malacologie, 

Musee National d'Histoire Naturelle, Paris? (Hertlein and 

Grant, 1972, p. 237)

Type locality. No locality cited originally.

Comparison. "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.

"The question as to whether this species is cosmopolitan or 

whether several closely related forms are involved has been discussed by several authors. E.A. Smith [1902, p. 163] stated that 

shells of this species could not be separated with certainty from 

allied forms. More recently Soot-Ryen [1951, p. 31], in a discussion of Antarctic shells similar to K. suborbicularis, stated that 

the relationship of such forms is still unsettled but he suggested 

that probably a number of nearly related species are concerned 

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 chironi Carpenter illustrated by Palmer (1958, pi. 9, 

figs. 6-10}.

"Kellia rotunda Carpenter was described as much larger than 

K. suborbicularis and nearly round in outline." (Hertlein and 

Grant, 1972, p. 237)

Geographic range. Living: Bering Sea and Pribilof Islands to 

Isla Tiburon, Golfo de California; fossil: southern California and 

Baja California Norte.

Geologic range. Pliocene to Holocene (table 1).

Occurrence in California. Pliocene: Cebada Member, Careaga 

Sandstone (Woodring and Bramlette, 1950) and San Diego 

(Hertlein and Grant, 1972) Formation; Pliocene and Pleistocene: 

San Pedro Formation (Arnold, 1903); Pleistocene: unnamed 

strata near Los Angeles (Valentine, 1956; Kanakoff and 

Emerson, 1959), San Pedro Formation (Arnold, 1903), Newport 

Bay, and in San Diego (Arnold, 1903) and Baja California Norte 

(Valentine and Roland, 1969).

Habitat. Intertidally to 395 m (Hertlein and Grant, 1972); intertidally to 20 m in the eastern Pacific (Bernard, 1983).

Genus ALIGENA Lea, 1843

Shell small, valves somewhat trigonal with the anterior end 

longer. Hinge plate very narrow, usually with a fingerlike tooth 

below the umbo in each valve, right-valve tooth slightly larger 

than the left, and a long oblique socket for the resilium ending 

in a widening of the hinge plate that simulates a posterior lateral tooth.

Geographic range. Europe, Africa, North America.

Geologic range. Miocene to Holocene.

Habitat. In temperate and tropical waters, intertidally to 

112 m (Hertlein and Grant, 1972); intertidally to 25 m in the 

eastern Pacific (Bernard, 1983). Inhabits relatively deep holes in 

rock made by borers, or empty shells such as mytilids, and is 

usually byssally attached (Yonge, 1951).

Subgenus ALIGENA

Subvertically pointed right cardinal tooth.

Aligena (Aligena) diegoana Hertlein and Grant 

Plate 1, Figures 6, 8-10, 12, 13

Aligena diegoana Hertlein and Grant, 1972, p. 235-236, pi. 44,

figs. 1, 6; pi. 45, figs. 6, 7, 10, 11, 13.

Original description. "Shell roundly quadrangular, rather 

large for the genus, convex, the anterior is longer and 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 end 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 subtriangular, 

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
E8 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

lunular margin, behind this a very small cardinal lamella 

(lacking on some specimens) below the beak, and back of this 

the ligamental pit. Dimensions of holotype, a right valve, 

length 7.9 mm, height 6.1 mm, convexity (one valve), (approximately) 2 mm.)"

Holotype. LACMP 4547.

Type locality. LAM. 305. San Diego County, Calif. San Diego 

Formation, Pliocene.

Supplementary description. "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***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." (Hertlein and Grant, 1972, 

p. 236)

Comparison. "The general outline of Aligena diegoana***is 

somewhat similar to that shown in an illustration of a Recent 

specimen from off the west coast of Lower California 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. nuca Dall from Miocene strata in Maryland***. The new species also bears a resemblance to 

the east American Aligena laevis H. C. Lea 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 ligamental pit." (Hertlein and 

Grant, 1972)

Geographic range. Southern California.

Geologic range. Pliocene.

Occurrence in California. Pliocene: San Diego Formation 

(Hertlein and Grant, 1972).

Genus BORNIA Philippi, 1836

Transversely trigonal to trapezoidal, slightly inequilateral, 

flattened; surface smooth, polished, or faintly ribbed and striated. Ligament comprising a feeble external part, internal resilium 

without a lithodesma. Left-valve hinge with long, strong, posterior lateral tooth and a smaller, less distant anterior lateral together with a small cardinal closely adjacent to it; right valve 

with strong lateral sockets and a small anterior cardinal socket.

The shell of Bornia differs from that of Kellia in that the surface is radially striate or punctate, at least in part, lacks a 

periostracum, and has a narrower hinge with the posterior cardinal of the left valve greatly reduced in size.

Geographic range. Worldwide.

Geologic range. Paleocene to Holocene.

Subgenus TEMBLORNIA Keen, 1943

Short cardinals and shallow small resilium, so that posterior 

laterals, just behind it, look like cardinals; hinge plate straight 

under resilium.

Resembling Bornia in outline, with radial sculpture on anterior and posterior slopes; differing from Bornia in the structure

of the hinge; resilifer small and shallow, ventral margin of hinge 

plate entire, not bisected as in Bornia by the insertion of the 

resilium.

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.

Geographic range. North America, South America.

Geologic range. Eocene to Pliocene.

Bornia (Temblornia) triangulata (Anderson and Martin) 

Plate 3, figures 17, 18

Donax triangulata Anderson and Martin, 1914, p. 41, pi. 3,

fig. 9.

Bornia (Temblornia) triangulata (Anderson and Martin). Keen, 

1943, p. 39, pi. 3, figs. 6, 7.

Original description. "Valves small, thin, trigonal, convex; 

beaks a little anterior to the middle; dorsal margins nearly 

straight; anterior extremity rounded; basal margin nearly 

straight; posterior end sharply rounded; an umbonal angulation 

extending from the beaks to the anterior and posterior extremities, forming areas sculptured with six or seven radial ribs; left 

valve with one cardinal and two lateral teeth; ends crenulated 

within; muscular impressions indistinct."

Holotype. GAS 130; CASG 65.02.

Type locality. CAS 65. Kern County, Calif. Round Mountain 

Silt, Miocene.

Supplementary description. "The shell is of shining porcellaneous texture with six to eight faintly incised grooves at the anterior and posterior ends. The grooves crenulate the inner 

margin slightly." (Keen, 1943, p. 39)

Geographic range. Southern California.

Geologic range. Miocene.

Occurrence in California. Miocene: Round Mountain Silt 

(Keen, 1943).

Bornia (Temblornia) frankiana Hertlein and Grant 

Plate 3, figures 13, 14

Bornia (Temblornia) frankiana Hertlein and Grant, 1972, p. 238- 

239, text fig. 11.

Original 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 

margin, lines of growth are accentuated (perhaps a result of erosion); remainder of the valve smooth except for somewhat 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."

Holotype. LACMP 4624.

Type locality. LAM 305c. San Diego County, Calif. San Diego 

Formation, Pliocene.

Comparison. "Bornia (Temblornia) frankiana***differs from 

the two other described species of Temblornia in its more
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E9

elongately trigonal outline and in the nearly straight anterior 

and posterior margins." (Hertlein and Grant, 1972, p. 239)

Geographic range. Southern California.

Geologic range. Pliocene.

Occurrence in California. Pliocene: San Diego Formation 

(Hertlein and Grant,1972).

Family MONTACUTIDAE 

Genus MYSELLA Angas, 1877

Shell triangularly ovate, anterior end longer, sculpture concentric; left valve with a large, diverging, flattened tooth posterior 

to the triangular resilifer; anterior margin of resilifer thickened 

and margined to simulate a transverse tooth; in front of this is a 

small socket; right valve with hinge margin on each side of 

umbo produced, which is overlapped by the hinge line of the opposite valve; the posterior toothlike edge interlocks above the 

cardinal tooth of the left valve and, the anterior which is 

shorter, is received in the socket in front to the ridgelike edge of 

resilifer. These toothlike margins of the right valve represent 

cardinal rather than lateral teeth.

Geographic range. Worldwide.

Geologic range. Miocene to Holocene.

Habitat. 2 to 97 m in the eastern Pacific (Bernard, 1983).

Subgenus ROCHEFORTIA Velain, 1877

Shell more or less rounded at both ends. Resilium with crests 

as bifid tooth. Differs from Mysella in having a stouter, shorter 

chondrophore with minute crest at its top on right valve and in 

having crests on the resilium.

Geographic range. Indian Ocean, Australia, North America.

Geologic range. Pliocene to Holocene.

Habitat. 5 to 120 m in the eastern Pacific (Bernard, 1983).

Mysella (Rochefartia) tumida (Carpenter) 

Plate 7, figures 5, 6

Tellimya tumida Carpenter, 1864, p. 602, 611, 643. 

Mysella tumida (Carpenter). Dall, 1899, p. 881, 892, pi. 87, fig. 7. 

Palmer, 1958, p. 88, pi. 7, figs. 8-12. Abbott, 1974, p. 473, 

fig. 5447. 

Mysella tumida Carpenter. Hertlein and Grant, 1972, p. 239-

240, pi. 44, figs. 2-5, 7, 8, 12.

Mysella cf. M. tumida (Carpenter). Addicott, 1966, p. C4, pi. 4, 

figs. 12, 13.

Original description. "Between [Mysella] bidentata and 

substriata: ossicle minute."

Holotype. USNM 5242.

Type locality. Puget Sound, Kennerley, Wash. (Palmer, 1958). 

Holocene.

Supplementary description. "***moderately compressed, 

somewhat triangular in shape. The tiny beaks are almost at the 

posterior end. The hinge teeth are large in comparison with 

other species." (Abbott, 1974, p. 473)

Comparison. "The species described by Dall as Mysella pedroana 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." (Hertlein and Grant, 

1972, p. 240)

Geographic range. Living: Shumagin Islands, Alaska, to 

Laguna Scammon, Baja California Sur; fossil: middle California 

to Baja California Norte.

Geologic range. Pliocene to Holocene.

Occurrence in California: Pliocene: Graciosa Member, Careaga 

Sandstone (Woodring and Bramlette, 1950) and San Diego Formation (Hertlein and Grant, 1972); Pleistocene: unnamed strata 

at Point Ano Nuevo, San Mateo County, Calif. (Addicott, 1966) 

and at Bahia San Quintin, Baja California Norte (Hertlein and 

Grant, 1972).

Genus THECODONTA A. Adams, 1864

Transversely rounded, convex, very inequilateral, posterior 

part much elongated. Sculpture concentric. Anterior left lateral 

curved, gradually increasing subparallel to margin, then 

straightened along oblique resilium. Posterior laterals remote, 

thickened.

Subgenus PRISTES Carpenter, 1864

More transverse than oblique, with scarcely projecting beaks 

and arcuate anterior, transversely serrated laterals; duplicate 

subparallel left posteriors.

Geographic range. California.

Geologic range. Pliocene to Holocene.

Thecodonta (Pristes) oblongus (Carpenter) 

Plate 4, figures 3, 4

Pristes oblongus Carpenter, 1864, p. 611, 643. Palmer, 1958, 

p. 89, pi. 9, figs. 11-13. Hertlein and Grant, 1972, p. 240- 

241, pi. 44, figs. 9, 10, 13, 14.

Original description. "Like Tellimya, with long marginal 

teeth, serrated near hinge."

Lectotype. USNM 15592 (Palmer, 1958).

Type locality. San Pedro, Calif. (Palmer, 1958). Holocene.

Supplementary description. "3 to 5 mm., quadrate, resembling a Nucula in shape, with the umbones at the anterior truncated end. Dorsal margin arching, below it one of the long 

cardinal teeth is serrated. Posterior end somewhat pointed. 

Lunule small and concave." (Abbott, 1974)

Geographic range. Living: Monterey, Calif, to Baja California 

Sur; fossil: Southern California.

Geologic range. Pliocene to Holocene.

Occurrence in California. Pliocene: San Diego Formation 

(Hertlein and Grant, 1972); Pleistocene: Unnamed strata at 

Crown Point, San Diego (Valentine (1959).

Habitat. Occasionally found living commensally under the 

girdle of the chiton Stenoplax conspicua (Pilsbry). (Morris and 

others, 1980)

Genus NEAEROMYA Gabb, 1873

Transversely subquadrangular to trigonal, finely striated. 

Right strong anterior laminar tooth and oblique posterior enlarged margin; oblique resilium between them; left thinner oblique anterior.
E10 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Geographic range. Central America, North America, Europe. 

Geologic range. Pliocene to Holocene.

Subgenus ORBITELLA Dall, 1900

Anterior margin broadly rounded, elongate, thus very 

inequilateral.

Geographic range. United States: Florida and Alaska to 

Mexico.

Geologic range. Miocene to Holocene.

Habitat. 0 to 50 m in the eastern Pacific (Keen and Coan, 

1974).

Neaeromya (Orbitella) compressa (Dall) 

Plate 4, figures 5, 7

Erycina (Pseudopytkina) compressa Dall, 1899, p. 888, pi. 87,

figs. 1, 8. 

Pseudopythina compressa (Dall). McGinitie, 1959, p. 173, pi. 19,

figs. 2, 3, 5.

uOrbitella"compressa (Dall). Roth, 1979, p. 293-294, pi. 3, 

figs. 6, 7.

Original description. "Shell large, subquadrate, thin, moderately compressed, white, covered with a conspicuous, thin, wrinkled, partly glossy periostracum; nearly equilateral, the 

posterior end slightly broader, both ends rounded, the basal 

margin nearly straight; beaks inconspicuous, surface with 

strong, irregular incremental lines, but no radial sculpture; pallial scar rather wide and irregular, merging into the subequal, 

rather narrow adductor scars; resilium large, wide, and long, 

more or less calcareous ventrally, left valve with one obscure 

cardinal tooth, right valve with the tooth better developed; the 

right dorsal valve margins overlap those of the left valve a little, 

but there are no distinct lamella. Lon. 18, alt. 13, diam. 6 mm."

Holotype. USNM 107855.

Type locality. "Dredged on muddy bottom in from 2 to 28 

fathoms in the eastern part of Bering Sea, south of Nunivak Island, the eastern Aleutians, and southward to Sitka, Alaska."

Supplementary description. "Keen and Coan (1974) and F.R. 

Bernard (pers. comm.) suggest that the customary assignment of 

this species to Pseudopythina Fischer, 1878, is open to question. 

The hinge characters are approximately those of Orbitella, but 

the shell is unusually large for that genus. Among west American bivalves, the most closely related species seems to be 

'Pseudopythina'rugifera (Carpenter, 1864), which in turn may 

have affinities to the genus Pythinella Dall, 1899, of the North 

American east coast and the west American tropics." (Roth, 

1979, p. 294)

Geographic range. Living: Alaska to Mexico; fossil; northern 

California.

Geologic range. Pliocene to Holocene.

Occurrence in California. Pliocene: Lower part of the Rio Dell 

Formation (Roth, 1979).

Habitat. 0 to 50 m (Keen and Coan, 1974); 7 to 90 m on crustaceans (Abbott, 1974).

Family SPORTELLIDAE 

Genus BASTEROTIA Mayr in Homes, 1859

Shell small, subquadrate corbuliform, with a sharp carination 

running from the beak posteriorly. Valves convex, usually solid,

the beaks prosogyrate. 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 large, hook-shaped cardinal tooth in each valve, bordered behind or in front by a deep socket; the socket lies in 

front of the tooth in right valve and behind it in left. No pallial 

sinus.

Geographic range. Worldwide.

Geologic range. Miocene to Holocene.

Habitat. 10 to 1,170 m (Hertlein and Grant, 1972); intertidally to 45 m in the eastern Pacific (Bernard, 1983).

Subgenus BASTEROTELLA Olsson and Harbison, 

1953

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.

Geographic range. Europe, North America.

Geologic range. Miocene to Holocene.

Habitat. Intertidally to 45 m in the Galapagos Islands. 

(Bernard, 1983).

Basterotia (Basterotelld) hertleini Durham 

Plate 9, figures 8, 14

Basterotia hertleini Durham, 1950, p. 94-95, pi. 25, figs. 4, 11. 

Basterotia (Basterotella) hertleini Durham. Keen, 1971, p. 145,

fig. 343. Bernard, 1983, p. 33. 

Basterotia californica Durham, 1950, p. 94, pi. 25, figs. 9, 13.

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." (hertleini)

"Shell small, moderately thin, elongate subquadrate, moderately inflated; ornamented by irregular concentric growth lines; 

beak not very prominent; an angulation running from umbo to 

posterior ventral margin; beak slightly anterior to midpoint of 

shell; a prominent projecting cardinal tooth in each valve, slanting anteriorly, a deep 'socket' adjacent posteriorly in left valve." 

(californica)

Holotype. UCMP 32274; of californica UCMP 32668.

Type locality. Isla Carmen, Baja California Sur. Comondu 

Formation, Pliocene. Of californica, Bahia Santa Inez (27° N, 

112° W). Unnamed Pleistocene strata.

Supplementary description. "The smooth shell is rounded 

anteriorly and posteriorly in the adult, with a weak ridge setting off the posterior slope; young shells are proportionately 

longer, more truncate posteriorly, with a sharper ridge." 

(Keen, 1971, p. 145)

Comparison. "A growth series in the Stanford collection, 

dredged off the Mazatlan coast, bridges the difference in outline 

between B. californica and B. hertleini***. At the southern end 

of the range the relative proportions change slightly, so that the 

shell seems shorter and higher; this is the B. ecuadoriana, which 

may prove to be a geographic subspecies." (Keen, 1971, p. 145)
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE Ell

"This species may be distinguished from B. peninsulars (Jordan) 

by its greater length, greater width between the angulation and the 

posterior ventral margin, normally lesser inflation, and usually less 

sharp angulation." (Durham, 1950, p. 95)

Geographic range. Living: Baja California Sur to Ecuador; 

fossil: Baja California Sur.

Geologic range. Pliocene to Holocene.

Occurrence in Baja California Sur. Pliocene: Comondu and 

Marquer Formations (Durham, 1950); unnamed Pleistocene sediments, Bahia Santa Inez (27° N, 112° W) (Durham, 1950).

Habitat. Intertidally, nestling in crevices and offshore to 46 m 

(Keen, 1971).

Family CARDITIDAE 

Genus CARDITA Bruguiere, 1792

Transversally inequilateral, trapezoidal or modioliform, with 

nodulose radial ribs. Hinge with obliquely trigonal divergent cardinals in left valve and faint anterior laterals.

Geographic range. Worldwide.

Geologic range. Paleocene to Holocene.

Habitat. The carditids are shallow-water mollusks, many attaching themselves under rocks by a byssus. (Keen, 1971)

Subgenus CARDITA

Relatively small, short; lunule not depressed. 

Geographic range. Europe, Africa, Asia, Australia, North 

America.

Cardita (Cardita) superiaris Waring 

Plate 4, figures 9, 11

Cardita superioris Waring, 1917, p. 91.

Original description. "Shell small, very convex; beaks large, 

incurved; anterior end deeply excavated under the beaks; margin 

broadly rounded; basal margin broadly curved; posterior obliquely and convexly truncated; cardinal margin sloping and 

slightly convex; shell slightly concave near the cardinal margin 

and flared; surface ornamented by about 23 broad, slightly 

rounded ribs which are broader than the interspaces. A few 

casts of this species were obtained from the upper beds. Locality 

8, L.S.J.U. Pal. Coll."

Holotype. CAS/SU 143; CASG 61913.06.

Type locality . SU 2696. Ventura County, Calif. Llajas Formation, Eocene.

Geographic range. Southern California. 

Geologic range. Eocene.

Occurrence in California. Eocene: Llajas Formation (Waring, 

1917).

Subgenus BYSSOMERA Olsson, 1961

"Shell elongated, the posterior side generally wider, with a 

high, arched or vaulted umbonal angle extending from the beak 

to the posterior ventral margin, the posterior set of ribs strongly 

developed, the more anterior one often flattened to nearly obsolete, the anterior-ventral side depressed. Hinge weak, the lateral 

teeth much reduced in size and more or less vestigial. Lunule 

small or absent." (Olsson, 1961)

Geographic range. Baja California Sur to South America. 

Geologic range. Pliocene to Holocene.

Cardita (Byssomera) affinis Sowerby 

Plate 9, figures 11, 13

Cardita affinis Sowerby in Broderip and Sowerby, 1833, p. 195. 

Glans affinis (Sowerby). Grant and Gale, 1931, p. 278. Durham,

1950, p. 72, pi. 17, figs. 2, 9. 

Carditamera (Byssomera) affinis (Sowerby). Olsson, 1961, p. 189-

190, pi. 26, figs. 3-3d. 

Cardita (Byssomera) affinis Sowerby. Keen, 1971, p. 107, fig. 237.

Original description. "Card, testa oblonga, pallida, fuscovarid, latere antico brevi, postico elongate; costis paucis latis radiantibus, anticis obsoletiusculis, posticis prominentibus 

angulosis, subsquamigeris: long. 1.4, lat. 0.6, alt. 0.6 poll."

Holotype. In Cummings collection.

Type locality. "Dredged from sandy mud, at a depth of from 

six to twelve fathoms, in the Bay of Montejo and Gulf of 

Nocoiya." Holocene.

Supplementary description. "Shell elongate, rectangular, 

often large (length to 70 mm.), with the umbones and beaks 

placed between the anterior one-fourth and one-fifth, the 

anterior side, therefore, much shorter and narrower than the 

posterior. Dorsal and ventral margins long and fairly straight, 

subparallel, the anterior margin rounded, the posterior wider 

and subtruncate. The posterior umbonal slope is high and 

angular and usually more heavily sculptured. Sculpture formed 

by ribs, usually numbering about 17; of these, the six posterior 

ones and along the umbonal slope are large and usually coarsely 

scabrous, the others placed more anteriorly small and sometimes 

so low or flattened as to form smooth, colored radial rays. Hinge 

variable, the teeth sometimes much distorted and partly obsolete 

but when fully developed in the following form; the left valve 

has large, anterior cardinal tooth bordered on each side by deep 

sockets while the posterior cardinal tooth is a slender, narrow 

lamina separated from the nymph by a groove; the right valve 

has a large, slender cardinal tooth bordered in front by a deep 

socket; the left anterior tooth is small and placed close to the 

main cardinal." (Olsson, 1961, p. 190)

Geographic range. Living: Golfo de California to Peru; fossil: 

Baja California Sur.

Geologic range. Pliocene to Holocene.

Occurrence in Baja California Sur. Pliocene: Comondu and 

Marquer Formations (Durham, 1950); Pleistocene: unnamed 

strata on Isla Carmen, Isla San Diego, Isla Coronado, and Golfo 

de California (Emerson and Hertlein, 1964).

Habitat. Living in close quarters as under stones and along 

narrow crevices (Olsson, 1961). Intertidally to 27 m on the Galapagos Islands (Bernard, 1983).

Subgenus STROPHOCARDIA Olsson, 1961

"Shell rounded cordate, solid, with high umbones and strongly 

prosogyrately coiled beaks over a small, deeply sunken lunule. 

Dorsal-posterior margin flattened, escutcheon-like. Sculpture 

formed by relatively few, low, rounded ribs. Hinge plate massive, 

the right valve with a large, stout, more or less hooked cardinal 

tooth, the left valve with two cardinal teeth and a large central 

socket; no vestigial laterals." (Olsson, 1961)

Geographic range. Living: Gulfo de California to Ecuador and 

the Galapagos Islands; fossil: Baja California Sur.

Geologic range. Pliocene to Holocene.
E12 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

TABLE 2. Geologic and geographic distribution of the genera Cyclocardia, Glans, and Miodontiscus in the eastern Pacific region 

[H=Holocene; Ple=Pleistocene; Pl=Pliocene; M=Miocene; O=Oligocene; Pa=Paleocene]

Species Alaska British WashColum- ington 

bia

Oregon California Baja California

Northern Middle Southern Norte Sur

Genus Cyclocardia

Subgenus Cyclocardia 

barbarensis (Stearns).... 

californica (Dall)......... M

crebricostata (Krause)... PI to H H PI to Pie

kirkerensis (Clark)....... O

montereyana (Arnold)... M

occidentalis (Conrad).... 

ventricosa (Gould)....... M to H M to H M to H M to H PI to H H

Genus Glans

Subgenus Glans 

subquadrata (Carpenter). H H H H H

Subgenus Centrocardita

PltoH

M to Pie

PI

PI to Pie 

PI to Pie H

PltoH Pie to H Pie to H

venenjormis ^uaoo;..... 

Genus Miodontiscus

prolongatus (Carpenter) M to H H H H H

ra; ""

H PltoH

Cardita (Strophocardid) megastropha (Gray) 

Plate 7, figures 1, 2, 11, 14

Venericardia megastropha Gray, 1825, p. 137, two figs. p. 138. 

Cardita megastropha (Gray). Hertlein and Strong, 1946, p. 106.

Durham, 1950, p. 71-72, pi. 16, figs. 6, 11.

Cardita (Strophocardia) megastropha (Gray). Olsson, 1961, 

p. 187-188, pi. 26, figs. 5, 5a. Keen, 1971, p. 109, fig. 244.

Original description. "Testa oblique cordata crassa albida, 

rufo variegata, costis convexis rugosis; margine cardinali 

crassissimo. long. unc. New Holland? E. dono. Dom. Bennet."

Holotype. BM(NH)?

Type locality. Isla La Plata, Ecuador (Hertlein and Strong, 1946).

Supplementary description. "Shell of medium or large size, 

solid, cordate, the ventral side rounded, the dorsal trigonal, with 

high umbones and strongly coiled beaks. The anterior-dorsal 

side is deeply impressed with a small, flattened lunule lying under and partially overhung by the beaks. Sculpture and appearance of specimens vary according to***degree of wear***in beach 

specimens***; the ribs assume greater prominence and are seen 

to be low, trigonal in section, their interspaces also trigonal and 

with a central line***." (Olsson, 1961)

Geographic range. Living: Golfo de California to Ecuador and 

the Galapagos Islands; fossil: Baja California Sur to the Galapagos Islands.

Geologic range. Pliocene to Holocene.

Occurrence in Baja California Sur. Pliocene: Marquer Formation (Durham, 1950); Pleistocene: unnamed strata on Isla 

Coronado, Isla Monserrate, and Isla San Diego in Golfo de California (Emerson and Hertlein, 1964).

Habitat. Offshore to 100 m (Keen, 1971); 30 to 150 m off the 

Galapagos Islands (Bernard, 1983).

Genus CYCLOCARDIA Conrad, 1867

Subtrigonal or short trapezoidal to cordiform, ventral margin 

well rounded; regular radial ribs may be closely spaced, crossed 

by numerous equidistant growth lines; beaks very small, tending 

to be erect.

Geographic range. Worldwide.

Geologic range. Cretaceous to Holocene (table 2).

Subgenus CYCLOCARDIA

Juvenile-stage ribs narrow, rounded, equally perlate, later becoming flattened and broadened, crossed by close-spaced growth 

lines; lunule large, smooth, slightly convex. Cardinal tooth on 

right valve of some species is bifid or grooved, but on other 

specimens this feature is faintly developed.

Geologic range. Oligocene to Holocene (Hertlein and Grant, 

1972).

Habitat. I to 2,210 m in the eastern Pacific (Bernard, 1983).

Cyclocardia (Cyclocardia) kirkerensis (Clark) 

Plate 9, figure 12

Cardium kirkerensis Clark, 1918, p. 140, pi. 12, fig. 5.

Original description. "Shell small, inequilateral; beaks fairly 

prominent and rather strongly prosogyrous; anterior dorsal slope 

very slightly concave; posterior dorsal slope straight, about equal 

in length to the anterior slope; anterior end broadly and regularly rounded; posterior end broadly subtruncate, the lower angle of 

the truncation being obscure. Surface sculptured by from seventeen to twenty V-shaped, nodose, radial ribs, with interspaces
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E13

averaging somewhat wider than the width of the ribs. Growth 

lines rather fine."

Holotype. UCMP 11165.

Type locality. UC 2033. Contra Costa County, Calif. Kirker 

Tuff, Oligocene .

Geographic range. Middle California.

Geologic range. Oligocene (table 2).

Occurrence in California. Oligocene: Kirker Tuff (Clark, 

1918).

Cyclocardia (Cyclocardia) montereyana (Arnold) 

Plate 7, figure 21

Venericardia montereyana Arnold, 1908, p. 380-381, pi. 35, fig. 4.

Original description. "Adult shell attaining a length of at 

least 10 mm., width about three-fourths of length, suboval in 

outline, compressed; umbones near anterior extremity, small, 

turned toward the front; anterior extremity short, regularly 

rounded; posterior extremity long, obliquely projected below, 

quite sharply rounded; surface sculpture by about 22 moderately 

broad radiating ribs and numerous subequally spaced concentric 

lines, radiating and concentric systems together giving a 

cancellate appearance."

Holotype. USNM 165464.

Type locality. Newell Creek, 2.4 km north of confluence with 

San Lorenzo River (SWVi, sec. 34, T. 9 S., R. 2 W), Santa Cruz 

quadrangle, Santa Cruz County, Calif. Monterey Shale, Miocene.

Comparison. 'This species [C. montereyana] is probably allied 

to V. barbarensis Stearns and V. ventricosa Gould. It has more 

anterior umbones and has more numerous ribs (22 instead of 18) 

than the former, and is much flatter that the latter; its concentric sculpture is also more prominent than that in either of the 

recent species. Owing to the distortion of all the specimens of V. 

montereyana, it is impossible to say with certainty just what its 

original outline was, but it is believed to have been about as 

shown in the figured type." (Arnold, 1908, p. 380-381)

Geographic range. Middle California.

Geologic range. Miocene.

Occurrence in California. Miocene: Monterey Shale (Arnold, 

1908).

Cyclocardia (Cyclocardia) californica (Dall) 

Plate 7, figures 3, 4

Venericardia (Cyclocardia) californica Dall, 1903a, p. 1431,

pi. 56, fig. 16.

Cardita californica (Dall). Keen and Bentson, 1944, p. 119. 

Cyclocardia californica (Dall). Woodring and Bramlette, 1950,

p. 85, pi. 8, fig. 16; pi. 10, figs. 7, 8; pi. 11, figs. 2, 3; pi. 15,

figs. 1, 2; pi. 21, fig. 5. Durham and Addicott, 1965, pi. 5,

figs. 16, 17.

Original description. "Shell of moderate size, rounded-trigonal, 

somewhat inequilateral; beaks small, prosogyrate, dorsal slopes 

steep, the anterior shorter, base arcuate; sculpture of fourteen to 

sixteen radial, more or less beaded or nodulous stout ribs, those on 

the posterior slope smaller, smoother, and less distant; interspaces 

channelled, subequal to the ribs; the whole with transverse 

concentric, somewhat irregular elevated lines. All the sculpture 

more feeble towards the base; lunule small, lanceolate, smooth; 

hinge normal, interior basal margin with a few coarse crenulations. 

Length 24.0, height 21.5, diameter 14.0 mm." 

Holotype. USNM 164558.

Type locality. "Pliocene(?) of California, five miles southwest 

of Guadalupe***," Santa Barbara County, Calif. Santa Barbara 

Formation, Pliocene and Pleistocene.

Supplementary description. "This species [C. californica] is 

characterized by widely spaced coarse nodes. The nodes are subdued or absent toward the ventral margin of large shells and on 

a few shells they are subdued at an early stage***. Arnold's collection from the type locality shows a considerable range of variation in outline and in the width of interspaces. The type is 

exceptionally elongate and has exceptionally wide interspaces." 

(Woodring and Bramlette, 1950)

Geographic range. Middle and southern California.

Geologic range. Miocene to Pleistocene.

Occurrence in the Californias. Miocene: Pancho Rico Formation (Durham and Addicott, 1965); Miocene and Pliocene: Sisquoc (Woodring and Bramlette, 1950) and Towsley (Kern, 1973) 

Formations; Pliocene: Cebada and Graciosa Members, Careaga 

Sandstone, Comondu Formation (Durham, 1950), and Foxen 

Mudstone (Woodring and Bramlette, 1950), Marquer Formation 

(Durham, 1950) and San Diego Formation (Rowland, 1972); Pliocene and Pleistocene: Fernando (Vedder, 1960), Santa Barbara 

(Dall, 1903b) and Saugus (Kew, 1924) Formations; Pleistocene: 

San Pedro Sand (Valentine and Meade, 1961) and unnamed 

strata on Isla Carmen and Isla San Marcos (Durham, 1950).

Cyclocardia (Cyclocardia) occidentalis (Conrad) 

Plate 9, figures 3-6

C.[ardita] occidentalis Conrad, 1855, p. 267. 1857, p. 73, pi. 5,

fig. 24. 

Cyclocardia occidentalis Conrad. Hertlein and Grant, 1972,

p. 230-231, pi. 43, figs. 4-6, 9-11. 

Cardita monilicosta Gabb, 1861, p. 371.

Venericardia borealis Conrad. Dall, 1874, p. 297. Not 

Venericardia borealis Conrad, 1831.

Original description. "Subtriangular, equilateral; ventricose; 

ribs 15, rounded, wider than the interstices, and regularly 

granulated by transverse lines." (occidentalis)

"Shell nearly circular; beaks small, submedian, cardinal border 

straight or faintly arcuate. Surface marked by from fourteen to 

seventeen large rounded ribs, strongly moniliform; interspaces 

narrow, acute. Posterior muscular impressions largest. Pallial 

line broad and distinct but not impressed. 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." (monilicosta)

Holotype. Missing and presumed lost (Woodring and others, 

1946), of monilicosta unknown.

Type locality. Santa Barbara, Calif. (Conrad, 1857). Santa 

Barbara Formation, Pliocene and Pleistocene; of monilicosta, 

Santa Barbara, Santa Barbara County, Calif. Santa Barbara 

Formation, Pliocene and Pleistocene.

Comparison. Cyclocardia occidentalis has 14 to 17 radial ribs 

and dorsal-ventral elongation. Cyclocardia ventricosa has 18 to 

20 radial ribs and anterior-posterior elongation.

Geographic range. Southern California.

Geologic range. Pliocene to Pleistocene.

Occurrence in California. Pliocene: San Diego Formation 

(Hertlein and Grant, 1972) and lower part of Saugus Formation 

(Squires and White, 1983); Pliocene and Pleistocene: Fernando 

(Arnold, 1907; Willett, 1946), San Pedro (Arnold, 1903), and 

Santa Barbara (Hertlein and Grant, 1972) Formations.
E14 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Cyclocardia (Cyclocardia) ventricosa (Gould) 

Plate 9, figures 9, 10

Cardita ventricosa Gould, 1850, p. 276. 1852, p. 417, atlas, p. 14, 

pi. 36, figs. 532, 532a. Grant and Gale, 1931, p. 272, pi. 13, 

figs. 9a, 9b, 11.

Venericardia ventricosa (Gould). Oldroyd, 1924, p. 36, pi. 3, fig. 8.

Cyclocardia ventricosa (Gould). Yonge, 1969, p. 494-505, figs. 1-

9, 19, 24a. Hertlein and Grant, 1972, p. 231, pi. 43, figs. 3,

8. Coan, 1977, p. 380-382, figs. 12-15. Roth, 1979, p. 295-

296, pi. 4, fig. 3.

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 profunde 

crenulato; dente cardinal! valvae dextrae, elevato, crasso, 

triangulari. Lat. 3/4; alt. 5/8; lat. 1/2 poll."

Syntypes. USNM 3373.

Type locality. "Hab. Puget Sound." Washington, Holocene.

Supplementary description. "The largest of four single 

valves***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." (Hertlein and Grant, 1972)

Comparison. "Compared with C.[ardita] 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, 1850)

"The shell of C.[ardita] ventricosa is more elongately (anteriorposterior) rounded [than Cardita occidentalis] 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. [ardita] 

ventricosa montereyensis by A.G. Smith and Gordon. Inspection of a 

large series of specimens 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.[ardita] ventricosa redondoensis by J.Q. Burch." (Hertlein and 

Grant, 1972)

Geographic range. Living: Cook Inlet, Alaska, to Baja California Norte; fossil: Washington to southern California.

Geologic range. Miocene to Holocene; Graysian (molluscan) 

Stage in the Pacific Northwest (Addicott, 1976)

Occurrence in California. Pliocene: San Diego Formation 

(Hertlein and Grant, 1972); Pliocene and Pleistocene: Fernando 

(Eldridge and Arnold, 1907; Soper and Grant, 1932; Zinsmeister, 

1970), Pico (Grant and Gale, 1931), San Pedro (Arnold, 1903), 

and Rio Dell (Roth, 1979) Formations; Pleistocene: Timms Point 

Silt Member, San Pedro Formation (Arnold, 1903) and unnamed 

strata in southern California (Grant and Gale, 1931) and Newport Bay area, California (Kanakoff and Emerson, 1959).

Habitat. 20 to 628 m in the eastern Pacific (Bernard, 1983); 

22 to 620 m (Coan, 1977); 14 to 574 m but more common in 

depths of 200 m or less on the southern California borderland 

(Jones and Thompson, 1987).

Cyclocardia (Cyclocardia) crebricostata (Krause) 

Plate 7, figures 23, 24; plate 9, figures 1, 2

Cardita borealis var. crebricostata Krause, 1885, p. 30, pi. 3, fig. 5. 

Cyclocardia crebricostata (Krause). Coan, 1977, p. 378-379, 

figs. 6, 7. Roth, 1979, p. 297-298.

Cyclocardia (Cyclocardia) crebricostata (Krause). Bernard, 1979,

p. 40-41, figs. 63, 64.

Venericardia (Cyclocardia) alaskana Dall, 1903b, p. 710-711. {Introduced for Venericardia borealis Conrad, 1890, in part.}

Original description. "Die Zahl der Rippen betragt 22-25; der 

Schlossrand ist dick, die Wirbel liegen central und sind nicht 

zerfressen; in der Nahe der Wirbel sind die Rippen durch 

concentrische Furchen deutlicher und regelmassiger crenulirt als 

bei der vorigen. Die gitterartige Sculptur der Rippen ist wie bei 

der vorigen. Die grossere Schale zeigt folgende Maasse: long. 24, 

alt. 22, 1/2 crass. 6 1/2 mm." (crebricostata)

'This species is that which from the Pacific has usually been 

named V. borealis Conrad, and I can only ascribe the long acceptance of this determination, made by Dr. Carpenter, to the absence of a good series of the Eastern shell. After comparing them 

no one can hesitate to separate them specifically. There is a distance of several thousand miles between their nearest points of 

approach to each other in range, as far as known. In a general 

way, until Dr. Stearns looked into the matter in 1890, all the 

Pacific Cyclocardias were lumped together under the name of borealis Conrad.

"The present species is ovate, compressed, with 23-25 uniform 

and elegant radial ribs with narrower interspaces, distinct to the 

margin of the shell and covered with a dark yellow-brown velvety periostracum, the hairs in close radial lines. The ribs are 

slightly granular near the low beaks; the lunule narrow and 

long. The hinge is solid, with the right anterior and posterior 

cardinals nearly obsolete; the interior is chalky white and is figured in the Proc. U.S. Nat. Mus., XIII, pi. XVI, fig. 8, under the 

name of C. borealis. It attains a height of 35, a length of 39, and 

a diameter of 16 mm. The animal is viviparous and incubates an 

enormous number of young shells until the adult sculpture is 

fairly initiated. The brood is fully ripe in August in the Arctic 

Sea, and about June 1 in the Aleutian Islands. The variability of 

the shell is chiefly in outline, some specimens being longer than 

others." (alaskana)

Lectotype. Institut fur Spezielle Zoologie und Zoologisches 

Museum der Humboldt-Universitat, Berlin, 37934 (Coan, 1977); 

of alaskana USNM 109271 (Coan, 1977).

Type locality. Saint Paul Island, Bering Sea, Alaska. 

Holocene; of alaskana, Bering Sea, Alaska. Holocene.

Supplementary description. "This variable species may be 

recognized by its large number of ribs (22 to 25) and its heavy 

periostracum with radially arranged hairs. Its hinge is long and 

narrow, and the shells are ovate and rather compressed." (Coan, 

1977, p. 379)

"Shell circular to nearly ovate, inflated, thick, maximum 

length 40 mm. Surface ornamented with 18-30 rounded ribs with 

equal interspaces crossed by numerous small concentric folds resulting in a scalariform appearance. Periostracum dark brown, 

velvety. Beaks small, erect, usually eroded. Interior polished, 

shell margins crenulated. Hinge delicate for the genus. Left 

valve with large central bifid cardinal and curved, elongated posterior cardinal tooth. Right valve with large central cardinal and 

thin laminar posterior cardinal tooth. External ligament placed 

on well-developed nymphs. Adductor muscle scars equal, deeply 

impressed. Pallial line impressed. No pallial sinus." (Bernard, 

1979)

Comparison. "This species is allied to the North Atlantic C. 

borealis (Conrad, 1831) but is distinguishable by the thinner 

shell, more delicate ribs, and weaker hinge." (Bernard, 1979)

Geographic range. Living: Alaska and southern Sakhalin; fossil: Alaska to southern California.

Geologic range. Pliocene to Holocene.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E15

Occurrence in California. Pliocene: Lower part of the Rio Dell 

Formation (Roth, 1979) and lower part of the Fernando Formation (Willett, 1946); Pleistocene: Elk River Formation (Roth, 

1979).

Cyclocardia (Cyclocardia) barbarensis (Stearns) 

Plate 5, figures 9, 15

Venericardia barbarensis Stearns, 1890, p. 214, pi. 16, figs. 3, 4.

Oldroyd, 1924, p. 111-112, pi. 43, figs. 9, 11. 

Cardita barbarensis (Stearns). Grant and Gale, 1931, p. 274. 

Cyclocardia barbarensis (Stearns). Woodring and others, 1946, 

p. 82-83, pi. 31, figs. 11, 12. Coan, 1977, p. 376-377, fig. 2.

Original description. "Shell rounded, inequilateral, variable 

in outline, more or less oblique, moderately convex. Beaks small, 

slightly elevated and turned forward. Surface ornamented with 

nineteen to twenty radiating ribs usually somewhat granulous, 

and generally obscure on the extreme anterior and posterior 

margins of the valves. Epidermis a dingy yellowish-brown, 

thicker toward the ventral margin and sides of the valves thin 

and commonly eroded at or toward the umbos. Lunule small, 

slightly sunken, faintly defined. Hinge line small, not thick; 

hinge composed of, in the left valve, a single strong cardinal 

sloping posteriorly and a smaller tooth often obscure, slanting 

anteriorly; a third tooth-like process is generally present, situated under and apparently a projection of the edge of the lunule. 

This latter varies much in prominence in different specimens, 

and is often but barely perceptible. The hinge in the right valve 

is characterized by a single strong cardinal tooth with a slanting, somewhat sinuous groove above, and a slight notch and 

tooth-like point below the upper part of the lunule; this latter 

character is frequently inconspicuous and feeble. The valves are 

rather thin and somewhat translucent, bluish-white on the inside and showing the ribs when held up to the light. Length, 15; 

height, 15; diameter, 11 mm."

Lectotype. USNM 104045 (Coan, 1977).

Type locality. Station 2840 off Santa Barbara, Calif. Holocene.

Supplementary description. "Shells of this species are thin, 

with 19 to 20 low ribs and a thin, dark periostracum." (Coan, 

1977)

Comparison. "This species [barbarensis] has much less 

prominent umbones, a thinner, more elongate hinge, and more 

ribs than [C.] ventricosa Gould. It appears to be closer to [C.] 

crebicostata (Krause) and may be a southern race of that northern species." (Grant and Gale, 1931, p. 274)

"Its [C. barbarensis] hinge is narrower than that of 

Cyclocardia ventricosa redondoensis; its beaks are smaller, and 

its shape more oblique." (Coan, 1977)

Geographic range. Living: Southern California; fossil: southern California.

Geologic range. Pliocene to Holocene.

Occurrence in California. Pliocene: upper part of Capistrano 

Formation (Kern and Wicander, 1974) and Lomita Marl Member, San Pedro Formation (Woodring and others, 1946); Pliocene 

and Pleistocene: Fernando Formation (Soper and Grant, 1932); 

Pleistocene: San Pedro and Santa Barbara Formations (Grant 

and Gale, 1931). ["Although reported from the Timms Point silt, 

San Pedro sand, and Palos Verdes sand***perhaps some of the 

records are based on worn specimens of C. aff. C. occidentalis." 

(Woodring and others, 1946)]

Habitat. 37 to 2,210 m in the eastern Pacific (Bernard, 1983). 

From 5 to 210 m, with some suggestion of deeper occurrence to

the south; on both sand and rocky bottoms (Coan, 1977). Broods 

its young (Jones, 1963).

Genus GLANS Mergerle von Muhfeld, 1811

Shell bearing a general resemblance to carditids such as 

Carditamera but small, subquadrate in outline; hinge with well 

developed anterior and posterior laterals.

Geographic range. Asia, North and East Africa, Central 

America.

Geologic range. Paleocene to Holocene.

Habitat. Intertidally to 100 m in the eastern Pacific 

(Bernard, 1983).

Subgenus GLANS

Truncate posteriorly, with nodulose or granular rounded ribs, 

posterior ones unequal in some species. Lateral teeth well developed.

Geographic range. Europe, Asia, North and East Africa, 

North America.

Glans (Glans) subquadrata (Carpenter) 

Plate 5, figures 10, 11

Lazaria subquadrata Carpenter, 1864, p. 536, 627, 642. 

Glans subquadrata (Carpenter). Palmer, 1958, p., 82, pi. 7, 

figs. 1-4. Yonge, 1969, p. 505-509, figs. 10-13, 20-22. 

Hertlein and Grant, 1972, p. 232, pi. 43, figs. 16, 18, 19, 

22, 30. Coan, 1977, p. 382-383, fig. 16.

Glans minuscula Grant and Gale, 1931, p. 277, pi. 13, figs. lOa, 

lOb. [Unnecessary replacement name].

Original description. "Hinge of Lazaria: outside like Cardita 

variegata juv."

Lectotype. USNM 15681 (Coan, 1977).

Type locality. Monterey, Calif. Holocene. (Designated by 

Coan, 1977).

Supplementary description. "The outside of this remarkable 

little species is typically carditoid; the hinge is intermediate between Lazaria and Cypricardia." (Carpenter, 1865, p. 178)

"A minute left valve***has a well-preserved prodissoconch 

sculptured with strong concentric lamellae. Well-preserved 

minute Recent shells show the same prodissoconch sculpture." 

(Woodring and Bramlette, 1950)

Geographic range. Living: British Columbia to Baja California Sur; fossil: southern California to Baja California Sur.

Geologic range. Pliocene to Holocene.

Occurrence in California. Pliocene: Cebada Member of the 

Careaga Sandstone (Woodring and Bramlette, 1950), San Diego 

(Hertlein and Grant, 1972), and lower part of the San Pedro (Grant 

and Gale, 1931) Formations; Pleistocene: unnamed strata in southern California and Baja California Norte and Sur (Jordan, 1926; 

Valentine, 1957; Valentine and Meade, 1961; Valentine and Roland, 1969), and on San Nicolas Island (Vedder and Norris, 1963).

Habitat. Intertidal zone to 91 m (Hertlein and Grant, 1972); 

intertidal to 100 m (Bernard, 1983). Almost all records are from 

rocky areas where the animal attaches itsef to rocks with a byssus (Coan, 1977). It broods its young (Yonge, 1969).

Subgenus CENTROCARDITA Sacco, 1899

Posterior margin rounded, with equal squamose or echinate 

ribs. Hinge with almost obsolete small laterals.
E16 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Geographic range. Europe, East Africa, Australia, western 

North America. 

Geologic range. Eocene to Holocene.

Glans (Centrocardita) veneriformis (Gabb) 

Plate 7, figures 7-9

Cardita veneriformis Gabb, 1864, p. 215, pi. 32, figs. 285, 285a.

Dickerson, 1914, p. 131.

"Cardita" veneriformis Gabb. Stewart, 1930, p. 173, pi. 3, fig. 7. 

Glan[s] (Centrocardi[t]a) veneriformis Gabb. Zinsmeister, 1983, 

p. 63.

Original description. "Shell small, very convex, subquadrate; 

beaks rather large, strongly incurved; cardinal margin nearly 

straight; posterior end obliquely and convexly truncated; anterior 

end deeply excavated under the beaks, produced and narrowly 

rounded below; base broadly rounded; lunule broad, deeply impressed. Surface marked by about forty fine, acute, radiating ribs, 

with sometimes an intercalated one arising in the middle of the 

shell, and becoming as large as the others before it reaches the 

base; these are most numerous anteriorly, where all of the ribs 

are smaller than on the middle; margin strongly crenulated."

Holotype. ANSP 4381.

Type locality. West of Martinez, Contra Costa County, Calif. 

Paleocene(?).

Supplementary description. "The lunule is wide and impressed, the escutcheon is not preserved. There are six radial 

ribs to the two mm. interval on the central ventral margin. 

Some of the radial ribs near the anterior ventral border are apparently secondary and did not extend to the umbo. The ligament was opisthodetic. The hinge is unknown. Length, 9.8 mm.; 

height, 8.4 mm.; thickness of both valves, 7.5 mm." (Stewart, 

1930, p. 173)

Geographic range. Middle California.

Geologic range. Paleocene(?).

Occurrence in California. Paleocene(?): Martinez Formation(?) (Dickerson, 1914; Stewart, 1930).

Genus MIODONTISCUS Ball, 1903

Small, obliquely oblong, with strongly prosogyrate beaks and 

long, ill-defined lunule; sculpture of broad radial ribs crossed by 

concentric furrows.

Geographic range. Western North America, Japan.

Geologic range. Miocene (Japan) to Holocene.

Habitat. 9 to 128 m (Hertlein and Grant, 1972); 5 to 210 m 

in the eastern Pacific (Bernard, 1983).

Miodontiscus prolongatus (Carpenter) 

Plate 5, figures 12-14, 16

Miodon prolongatus Carpenter, 1864, p. 611, 627, 642. 

Miodontiscus prolongatus (Carpenter). Palmer, 1958, p. 83, 

pi. 8, figs. 1-7. Hertlein and Grant, 1972, p. 233-234, pi. 56, 

figs. 1-5. Coan, 1977, p. 383-384, figs. 17-19. 

Venericardia yatesi Arnold, 1907, p. 439-440, pi. 58, figs. 2a. 2b.

Original description. "Outside Lucinoid; hinge and scars 

nearer to Venericardia. Congeneric with Astarte orbicularis, 

J. Sby. Min. Conch, pi. 444, f. 2, 3 (non ejusdem, pi. 520, f. 2). 

G. Oolite; and with the Crag Cardita corbis." (prolongatus)

"Shell averaging between 4 and 5 millimeters in altitude, subcircular in outline, moderately convex. Beaks slightly posterior,

turned slightly forward, and somewhat prominent. Anterior margin slightly depressed in front of beaks, but convex below this; 

anterior angle somewhat more sharply rounded than posterior, 

giving the valve an obliquely protruding appearance anteriorly. 

Posterior margin and base regularly rounded. The sculpture consists of 8 or 9 broad falcate ribs separated by narrow incised 

interspaces and several (8 in the type) very prominent concentric 

imbrications of growth; in addition to the latter are numerous 

fine incremental lines. Hinge relatively narrow for one of this 

genus." (yatesi)

Lectotype. USNM 15472 (Coan, 1977); holotype of yatesi 

USNM 165248.

Type locality. Neah Bay, Washington. Holocene; of yatesi 

Bath-house Beach, Santa Barbara, Santa Barbara County, Calif. 

Fernando Formation, Pleistocene.

Supplementary description. "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 anteriorly. The external sculpture consists of broad, low, radiating ribs and widely spaced concentric, incised lines." (Hertlein and Grant, 1972, p. 233)

Geographic range. Living: Alaska to southern California; fossil: Russia, Alaska, and southern California.

Geologic range. Pliocene to Holocene.

Occurrence in California. Pliocene: Cebada and Graciosa 

Members of the Careaga Sandstone (Woodring and Bramlette, 

1950), Foxen Mudstone, Lomita Marl Member, of the San 

Pedro Formation, and San Diego Formation (Hertlein and 

Grant, 1972); Pliocene and Pleistocene: Santa Barbara Formation; Pleistocene: Timms Point Silt Member, San Pedro Formation (Woodring and others, 1946) and unnamed strata at 

Newport Bay, and on San Nicolas Island (Vedder and Norris, 

1963), Calif.

Habitat. 9 to 55 m (Hertlein and Grant, 1972); 5 to 210 m in 

the eastern Pacific (Coan, 1977; Bernard, 1983).

Subfamily VENERICARDINAE 

Genus VENERICARDIA Lamarck, 1801

Rounded trigonal, inequilateral, thick-shelled, with numerous 

radial ribs evenly elevated at young stage but becoming flattened and enlarged on adults.

Geographic range. Europe, Africa, North America.

Geologic range. Late Cretaceous to Eocene (table 3).

Geographic range. Europe, Africa, North America, New 

Zealand.

Comments. Figure 3 shows the phylogeny of Venericardia in 

the eastern Pacific.

Subgenus PACIFICOR Verastegui, 1953

Subtrigonal to rounded; immature ribs trifid, later becoming 

simple and rounded, nodulose to irregularly striated.

The posterodorsal area in the left valve is smoother than in 

the right, has fewer ribs, and the ribs are weaker.

Geographic range. Europe?, North America.

Geologic range. Late Cretaceous to Eocene.

Comments. Figure 3 shows the phylogeny of Pacificor in the 

eastern Pacific.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E17

TABLE 3. Geologic and geographic distribution of the genera Venericardia, Glyptoactis, and Milneria in the eastern Pacific region

[H=Holocene; Pl=Pliocene; E=Eocene; Pa=Paleocene; K=Cretaceous]

Species Wash- Oregon 

ington

California Baja California

Northern Middle Southern Norte Sur

Genus Venericardia 

Subgenus Pacificor 

aragonia diabloensis (Verastegui)......... 

aragonia joaquinensis (Yokes)............. 

calafia calafia (Stewart)...................... 

calafia gabbi (Verastegui)................... 

calafia lutmani (Turner)..................... 

calafia susanaensis (Verastegui)...........

clarki clarld Weaver and Palmer.......... E

clarki popenoei (Verastegui)................ 

hornii (Gabb)................................... 

mulleri Verastegui............................ 

nelsoni Verastegui............................ 

taliaferroi Verastegui......................... 

Subgenus Venericor 

vallecitosensis (Vokes)...................... 

venturensis (Waring)......................... 

Genus Glyptoactis 

Subgenus Claibornicardia 

domenginica (Vokes)......................... 

keenae (Verastegui)........................... 

marksi (Verastegui)........................... 

sandiegoensis (M.A. Hanna)............... 

Genus Milneria

minima (Dall).................................. 

E 

E

E?

Pa

E 

Pa

E 

Pa

E 

H

PatoE

E

E

E

E

E

E

E

Pa

Pa 

KtoPa

Pa

E 

E

PltoH

Pa? 

E

Pa

H H

Venericardia (Pacificor) taliaferroi Verastegui 

Plate 5, figures 3, 7, 8

Venericardia venturensis Waring. Taliaferro, 1944, p. 516. Not

Venericardia venturensis Waring, 1917. 

Venericardia (Pacificor) taliaferroi Verastegui, 1953, p. 38-39,

pi. 1, figs. 15, 16. Saul, 1986, p. 29, figs. 39, 40. 

Original description. "Shell small, convex, outline obliquely cordate, anterior and ventral margins broadly rounded, the posterior obtusely truncate, the postero-dorsal somewhat arched; 

umbonal area convex; beak prosogyrate, curved forward, low, at 

about the anterior one-fourth. Posterior area depressed, slightly 

concave, characterized by finer ribbing. Sculpture (well preserved 

in the holotype) consisting of 20 to 22 ribs; the anteriormost 3 

ribs V-shaped, the next 11 ribs tripartite with lateral terraces 

about one-fifth the width of the radials; ribs separated by Ushaped channels; the posterior 7 ribs V-shaped, the second from 

the last a little higher than the rest; interradials apparently obtusely V-shaped; with fine incrementals on the umbonal area, 

anteriorly coarsened to give the radials the appearance of being

crenulated; periodic constrictions of growth (annual rings) well 

marked. Lunule impressed, slopes downward and forward. Hinge 

and interior of the types concealed by coarse matrix."

Holotype. CAS/SU 7996; CASG 66526.01.

Type locality. NWVi, NEVi, sec. 30, T. 25 S., R. 10 E., Vi mile 

SSW [0.4 km] of Bench Mark 719, south of Williams Ranch on 

the Nacimiento River, Adelaida Quadrangle, San Luis Obispo 

County, Calif. Dip Creek Formation of Verastegui (1953), Upper 

Cretaceous and Paleocene.

Comparison. "Venericardia taliaferroi***vfSiS originally misidentified as V. venturensis Waring. The round ribs and the typical Pacificor distribution of fasciculate (terraced) ribs show that 

it is unrelated to V. venturensis which belongs to the subgenus 

Venericor***" (Verastegui, 1953).

Geographic range. Southern California.

Geologic range. Late Cretaceous to Paleocene.

Occurrence in California. Upper Cretaceous and Paleocene: 

Dip Creek Formation (Verastegui, 1953); Paleocene: basal part of 

San Francisquito Formation (Saul, 1986).
E18 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

AGE STAGE PHYLOGENY

.2,

clarki popenoei

clarki clarki

marksi

I 

domenginica

I

I

I

sandiegoensis

homii

"1

calafia gabbi

crescentensis

vallecitosensis

aragonia aragonia

aragonia joaquinensis

aragonia diabloensis 

I ^

calafia calafia

I

I

I

calafia lutmani

\ 

calafia susanaensis

I

I 

I

keenae

uenturensis 

I

mulleri

I

I

I 

nelson i

taliaferroi

Subgenus (Cla iborn ica rdia) (Venericor) (Pacificor)

Genus Glyptoactis Venericardia

FIGURE 3. Preliminary phylogenetic chart of Glyptoactis and Venericardia prepared by LouElla Saul, Los Angeles County Museum of 

Natural History. The species aragonia s. s. and crescentensis do not occur in the Californias but are found in Oregon and Washington, respectively. Stage names in quotation marks distinguish them from formations of the same name.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E19

Venericardia (Pacificor) nelsoni Verastegui 

Plate 1, figures 3, 20

Venericardia planicosta var. venturensis Waring. Nelson, 1925, 

p. 403 [faunal list]. Not Venericardia venturensis Waring, 

1917.

Venericardia (Pacificor) nelsoni Verastegui, 1953, p. 21-22, pi. 2, 

figs. 1, 5; pi. 3, fig. 5. Zinsmeister, 1983, pi. 1, fig. 20. Saul, 

1983, pi. 1, fig. 7.

Venericardia (Pacificor) transversaria Verastegui, 1953, p. 37- 

38, pi. 2, figs. 2-4.

Original description. "Shell large, heavy, ovate; outline 

smoothly rounded, umbo inflated, prosogyrate; the medial area 

defined by a sudden change of slopes on the anterior and posterior sides. Sculpture not well preserved in holotype; radials consisting of 22 rounded ribs which become obsolete toward the 

ventral border; umbonal sculpture in holotype lost by weathering; posterior area set off by five thin, crowded radials succeeded by two outermost ribs which are conspicuously wider; 

interradials linear; incrementals moderately strong, crowded in 

senile stage and producing a conspicuous thickening of the borders. Lunule of the left valve narrow, pointing downward and 

backward; pseudoescutcheon present, slightly concave, wide, 

bordered by a narrow ligamental groove; nymph long and narrow; ligamental pit large, excavated in a prolongation of the 

nymph. Hinge plate heavy, low and short with a sinuous ventral margin; left anterior cardinal (2) long trigonal, obliquely 

set, posterior cardinal (4b) relatively thin, slightly broadening 

ventrally. Interior of holotype filled with matrix concealing the 

pedal and adductor muscle scars; crenulations on the inner 

margin not distinct." (nelsoni)

"Shell large, thick, inflated, outline subquadrate. Umbo 

prominent, strongly curved forward (unfortunately beak, lunule, 

and part of the hinge are broken in the holotype); anterior margin broadly rounded, ventral margin gently curved, turning 

abruptly about 90° to the straight posterior margin. With typical Pacificor sculpture modified by superimposed wrinkled laminations consisting of 22 ribs; the 6 anterior radials 

characterized by having lateral riblets not reaching the anterior 

margin; 4 of the 6 ribs on the posterior area thin, 2 marginal 

ribs wider. Interradials linear in the antero-medial portion, becoming gradually wider and U-shaped in the posterior area. 

Pseudoescutcheon wide, concave, and distinct. Ligamental 

groove well developed. Hinge heavy, high, and short with a 

sinuous basal line; dentition not well preserved in the holotype, 

except the base of the massive and curved middle right cardinal 

(3b). Pedal muscle scar deep and large; adductor muscle scars 

deeply impressed. Shell conspicuously thickened at the posteroventral point of the posterior scar; pallial line irregular, rather 

far removed from the margin; inner marginal crenulations very 

coarse." (transversaria)

Holotype. UCMP 32804; of transversaria UCMP 32804A.

Type locality. UC 3765. Ventura County, Calif. Santa 

Susana Formation of Zinsmeister (1983), Paleocene; of 

transversaria UC 3765. Ventura County, Calif. Santa Susana 

Formation of Zinsmeister (1983), Paleocene.

Comparison. "V. mulleri has about 12 more ribs and***its 

lunule points downward and forward." (Verastegui, 1953, p. 22)

Geographic range. Southern California.

Geologic range. Paleocene.

Occurrence in California. Paleocene: Martinez (Verastegui, 

1953) and Santa Susana (Zinsmeister, 1983) Formations.

Venericardia (Pacificor) mulleri Verastegui 

Plate 1, figures 1, 5, 11

Venericardia (Pacificor) mulleri Verastegui, 1953, p. 20-21, pi. 2,

figs. 1, 5; pi. 3, fig. 5. Saul, 1983, pi. 1, fig. 8. 

Venericardia mulleri Verastegui. Smith, 1975, p. 470, pi. 2, fig. 8.

Original description. "Shell of medium to large size, gently 

convex, rounded in outline with broadly arcuate anterior and 

ventral margins and obtusely truncate posterior margin; narrow 

pointed umbones and low prosogyrate beaks at the anterior 

fourth. Surface ornamentation consists of 32 to 34 well-defined 

ribs extending from the beak to the margin, 24 ribs on the 

antero-medial portion and approximately 10 on the posterior 

area; faint, terrace-like secondary riblets evident on both sides 

of the first 10 anterior ribs and receding to the posterior umbonal area. Riblets one-fifth nearer the dorsal margin broaden 

away from the beak, and in the adolescent stage usually have 

one secondary riblet on the posterior side of the ribs; the remaining seven ribs narrower, crowded, and cordlike; (beak 

areas poorly preserved in all specimens examined). Interspaces 

are V-shaped at the umbo but become shallower and less 

sharply angular in harmony with the rib crests which are sharp 

near the umbo and increasingly rounded ventrally. Growth lines 

present throughout, more apparent in the anterior area, where 

they intercept the crests of ribs and give the appearance of 

nodes. Pseudoescutcheon present. Lunule short and deep, sloping forward, distinctly convex, outlined by an incised groove, 

ending ventrally in a depression in the right valve. Ligament 

opisthodetic, nymph narrow and elongate; ligamental pit shallow, elongate and bordered dorsally by an extension of the 

nymph. Hinge plate low, short, with ventral border distinctly 

sinuous; dentition of the right valve with a laminar anterior 

cardinal (3a) barely discernible on the posterior side of the 

lunular body, a medial obliquely cuneate cardinal (3b), and a 

slender posterior cardinal (5b). Pedal and adductor muscle scars 

not deeply incised. Pallial line entire and relatively far from the 

ventral margin. Crenulations of inner margin well marked in 

adolescent shell but obscure on a mature form."

Holotype: CAS/SU 7994.

Type locality. SU 2073. Fresno County, Calif. Base of Lodo 

Formation, Paleocene.

Comparison. "V. argentea, a contemporaneous form, differs 

from V. mulleri by its pronounced umbonal convexity with fuller 

umbones, and by the somewhat flatter ribs in the adolescent 

shell. V. rce/sorci** "resembles V. mulleri in the general outline of 

the shell but is distinguished by having only 21 ribs. V. 

susanaensis*** seems to be closely related to V. mulleri." 

(Verastegui, 1953, p. 21)

Geographic range. Middle and southern California.

Geologic range. Paleocene.

Occurrence in California. Paleocene: Coal Canyon Formation 

and basal part of Lodo Formation (Verastegui, 1953; Smith, 

1975).

Venericardia (Pacificor) calafia susanaensis Verastegui 

Plate 1, figures 14, 16-18

Venericardia (Pacificor) susanaensis Verastegui, 1953, p. 22-23,

pi. 5, figs. 1-4. 

Venericardia (Pacificor) hornii susanaensis Verastegui. Saul,

1983, pi. 1, fig. 14.
E20 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Original description. "Shell, large, thin, outline rounded to 

subquadrate, not known in detail due to the fragmentary nature 

of the material; umbonal area narrow, slightly inflated; beaks 

prosogyrate, distinctly low and pointing forward. Sculpture of 

holotype well preserved; 22 ribs, persisting to the margins, in 

the antero-medial portion and 8 in the posterior area; earliest 

ribs worn away but that which remains shows that they are tripartite and faintly beaded, at least in the anterior part of the 

shell; in the mature stage, the ribs of the antero-medial area 

rounded, those on the posterior area thin and crowded; the 

interradials V-shaped, reaching the ventral margin. Incrementals rough throughout the shell. Pseudoescutcheon narrow, concave, showing oblique lines of growth. Ligamental groove 

narrow; nymph thin and large, embracing anteriorly a linear 

ligamental pit. Hinge plate short and low with a sinuous basal 

margin, the sinuosity more pronounced in the right valve; dentition of arcuate-cuneate middle cardinal (3b), slightly concave on 

the wide basal margin, and a cordate posterior cardinal (5b) on 

the inner border of the nymph body; the left valve with a 

trapezoido-pyramidal, strong anterior cardinal (2), and a thin 

posterior left cardinal (4b), slightly thickened toward the ventral 

end. Interior of the holotype badly preserved; pedal muscle scars 

small and shallow, part of the shallowly incised posterior adductor muscle scar visible, posterior adductor scar placed unusually 

far from the hinge plate. Inner margin strongly crenulate."

Holotype. CAS/SU 8004; CASG 66527.01.

Type locality. "SU CA-33, McCray Oil Wells, Oil Canyon, 

Camulos Quad., Ventura Co., California." Uppermost Santa 

Susana Shale of Verastegui (1953), Eocene.

Geographic range. Southern California.

Geologic range. Eocene.

Occurrence in California. Paleocene and Eocene: Santa 

Susana Shale (Verastegui, 1953)

Venericardia (Pacificor) aragonia diabloensis Verastegui 

Plate 2, figures 8, 9; plate 5, figures 2, 5

Venericardia hornii Gabb, n. var.?. Clark and Woodford, 1927,

p. 92, pi. 15. 

Venericardia (Pacificor) diabloensis Verastegui, 1953, p. 27-28,

pi. 5, figs. 5-7, 7a.

Original description. "Shell large, slightly subquadrate, with 

inflated umbo and flattened ventral area; anterior margin 

broadly rounded, the ventral gently curved, and the posterior 

slightly truncate; beaks massive and curved forward, placed at 

about the anterior one-third. Umbonal sculpture consisting of 

26 finely beaded and in the anterior medial area laterally terraced ribs; on the posterior portion ribs cordlike, crowded and 

less distinct; adult sculpture characterized by 26 gently 

rounded, almost flat ribs separated by linear intercostals, ribs 

and intercostals gradually disappear with growth about 50 mm. 

from the beak, giving place to thick incrementals. Lunule convex, deeply inset, with lunular margin sloping almost vertically 

and ending in a pustule (in the left valve). Ligamental groove 

shallow. Hinge plate moderately high and long with a slightly 

sinuous ventral margin; nymph narrow but long; ligamental pit 

triangular, deeply incised. Dentition of the left valve consists of 

a scimitar-like, cuneate anterior cardinal (2), pointing toward 

and touching the lunular plate, with the inner face sloping uniformly toward the ventral margin of the hinge, and a thin posterior cardinal (4b), also sloping. Interior of the type filled with 

matrix, concealing the pedal and adductor muscle scars. Inner 

margins crenulate."

Holotype. CAS/SU 411; CASG 61967.01.

Type locality. "Marsh Creek, Brentwood, Contra Costa Co., 

California." Meganos Formation, Paleocene and Eocene.

Comparison. "V. diabloensis closely resembles V. lutmani 

Turner from Oregon in outline but differs in having two less ribs 

than the latter." (Verastegui, 1953, p. 28)

Geographic range. Middle California and Baja California 

Norte? (Flynn and others, 1989).

Geologic range. Paleocene and Eocene.

Occurrence in Californias. Paleocene(?): Bateque Formation 

(Flynn and others, 1989); Paleocene and Eocene: Meganos Formation (Verastegui, 1953).

Venericardia (Pacificor) calafia lutmani Turner 

Plate 2, figures 1, 2; plate 4, figures 1, 12, 13; plate 5, figure 1

Venericardia hornii subsp. lutmani Turner, 1938, p. 50, pi. 13, 

fig. 4; pi. 14, fig. 2. Weaver, 1942, p. 135, pi. 28, fig. 1; pi. 32,

fig. 1. 

Venericardia (Pacificor) lutmani Turner. Verastegui, 1953, p. 26-

27, pi. 7, figs. 305; pi. 8, fig. 8. 

Venericardia (Pacificor) hornii lutmani Turner. Givens, 1974, p. 47,

pi. 1, fig. 16; pi. 2, fig. 8. Saul, 1983, pi. 2, fig. 6. 

Venericardia (Pacificor') durhami Verastegui, 1953, p. 23, pi. 7,

figs. 1, 2. Flynn and others, 1989, p. 1,184, fig. 4 (4). 

fVenericardia (Pacificor) diabloensis Verastegui. Flynn and others, 1989, p. 1,184, Fig. 4 (2A, 2B). Not Venericardia 

(Pacificor) diabloensis Verastegui, 1953.

Original description. "Shell heavy, subquadrate; beaks small; 

27 ribs, the posterior 9 or 10 narrower and higher than the remainder, which are nearly obsolete with the exception of the anterior three or four; lunule very short, deep; ligamental groove 

long, narrow."

"Shell large, thick, distinctly round in outline; umbones inflated with the anterior slope more sharply curved than the posterior; beaks low, prosogyrate, situated at about the anterior 

one-third. Sculpture of 28 interradials, faintly represented over 

the main part of the disk; (sculpture on tips of beaks of holotype 

worn and not showing whether ribs are beaded or fasciculate); 

the antero-medial portion with 19 ribs and the posterior area 

with only 9, the 4 nearest to the dorsal margin being wider than 

the others. Lines of growth conspicuous over the greater part of 

the shell. Incrementals faint and smooth up to 25 mm. diameter 

becoming gradually coarser; dominating over obsolescent radial 

sculpture; a distinctive feature of the species. Lunule not well 

preserved, apparently small and deeply incised. Pseudoescutcheon 

narrow and concave. Hinge plate low and short; dentition in holotype poorly preserved, traces of the cardinal (2) of the left 

valve, and the anterior cardinal (3a) of the right valve resemble 

those of Venericardia susanaensis, n. sp. Interior of holotype concealed by matrix." (durhami)

Holotype. UCMP 33133; of durhami CAS/SU 8005; CASG 

66528.01.

Type locality. UC A-1233. Douglas County, Oreg. Umpqua 

Group, Roseburg Formation of Baldwin (1974), Eocene; of 

durhami "SU 829. 2.4 km W. of Vickers Hot Springs, Ventura 

Co., California." Juncal Formation, Eocene.

Supplementary description. "Shell large, heavy, subquadrate 

in outline, anterior end evenly rounded, ventral gently curved, 

posterior truncate; umbones inflated, with low, pointed beaks 

situated at about the anterior one-fourth. Sculpture in holotype 

not well preserved; 20 ribs in the antero-medial portion; only 6 

ribs preserved on anterior area, these show riblets which do not
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E21

reach the anterior margin; the visible intercostals linear; 

incremental coarse and over-ride ribs in the anterior area but 

fine on the obsolescent ribs of the ventral area. Lunule small, 

convex, deeply inset, sloping downward and slightly forward, 

the right lunule three times as large as the left one. 

Pseudoescutcheon present, flat and wide (not well preserved). 

Nymph thin and large ligamental pit deeply incised. Hinge 

plate high and long, with a sinuous ventral margin. Dentition 

strong, consists of a laminar, long, nearly vertical anterior right 

cardinal (3a), pointed downward and slightly backward; a flat, 

scimitar-like, ventrally sinuous medial right cardinal (3b); a 

cordlike posterior right cardinal (5b) placed on a wide flat 

nymphal body; the left valve with a low, cuneate anterior cardinal (2), the upper end touches the lunular plate, and a thin, low 

posterior left cardinal (4b), not well preserved in the holotype. 

Pedal muscle scars shallowly incised; the rest of the interior of 

the shell concealed by the matrix." (Verastegui, 1953, p. 27)

Comparison. "The new subspecies differs from V. hornii 

calafia Stewart in having three or four additional ribs. Specimens of the new subspecies from the Santa Susana shale of the 

Simi Valley region have 28 or 29 ribs and may be the initial 

form from which the later varieties or subspecies of V. hornii 

evolved by progressive elimination of ribs." (Turner, 1938: 50)

'This subspecies is distinguished from V. hornii by possessing 

27 ribs and a low beak while the latter is characterized by 22 

wide rounded closely spaced radial ribs. It differs from the subspecies calafia in having 3 or 4 more radial ribs. On the middle 

third of the shell the width of ribs is approximately two-thirds 

that of the interspaces." (Weaver, 1942, p. 135)

'This subspecies [lutmani] is similar in outline to V. hornii 

calafia, but is distinguished by a larger number (27-30) of radial 

ribs. As suggested by Turner (1938:50), V. hornii lutmani probably evolved into V. hornii calafia by reduction in the number of 

ribs." (Givens, 1974, p. 47)

Geographic range. Southern Oregon, southern California, and 

Baja California Norte.

Geologic range. Eocene.

Occurrence in the Californias. Eocene: Bateque, Juncal, and 

basal part of Llajas Formations (LouElla Saul, written commun., 

1989).

Venericardia (Pacificor) calafia calafia Stewart 

Plate 3, figures 1-7, 11, 16, 19

Venericardia hornii subsp. calafia Stewart, 1930, p. 168-170, 

pi. 11, fig. 2. Turner, 1938, p. 50, pi. 14, fig. 4. Weaver, 

1942, p. 134, pi. 28, figs. 6, 7; pi. 31, figs. 4, 5. 

Venericardia (Pacificor) calafia Stewart. Verastegui, 1953, p. 28-30. 

Venericardia (Pacificor) hornii calafia Stewart. Saul, 1983, p. 79,

pi. 2, figs. 9, 16, 17. Squires, 1984, p. 46, figs. lOn, o. 

Venericardia (Pacificor) oregonensis Verastegui, 1953, p. 25,

pi. 9, figs. 7-9. 

Venericardia (Pacificor) hertleini Verastegui, 1953, p. 24-25,

pi. 15, figs. 1, 2, 6. 

Venericardia hornii (Gabb), variety, Hanna, 1925, p. 286-287,

pi. 38, fig. 4; pi. 40, figs. !(?), 2.

Original description. "Shell large, heavy, almost circular, with 

small beaks: 24 radiating ribs on each valve, decorticated at the 

beaks, but a few of the anterior ribs still showing the lateral 

ridges and two of the posterior ribs of the left valve distinctly 

noded but apparently not ridged; on the central region, the ribs 

flatten and disappear when the shell is about 42 mm. long, as 

shown by the growth lines, the central area being quite smooth;

the anterior ribs gradually give way to prominent growth lines 

while the posterior ribs remain more or less distinct, but not 

prominent, to the posterior margin: hinge of type specimen not 

exposed. Length, 95 mm.; height, 86 mm.; thickness of both valves, 

53.5 mm.; no. 31450, Museum of Paleontology." (calafia)

"Shell large, thick, broadly rounded, not strongly inflated; 

antero-ventral margin broadly rounded, the posterior slightly 

truncated. Umbo curved forward; beak placed at about the anterior one-third; posterior area flattened, somewhat concave and 

defined by a sudden change from coarse to fine ribs. Sculpture 

consists of 25 ribs which become obsolete near the margins. The 

18 ribs in the antero-medial portion sharply angular on the 

beak, gradually become slightly flattened to the second annual 

ring then flatly rounded; the four or five ribs on the anterior 

area slightly terraced; those on the posterior area angular in 

the early stage become rounded later, the three ribs next to the 

gentle umbonal ridge thinner and crowded, and the last four 

near the posterior margin are much wider. Interradials Ushaped to the second annual ring, after which they become welldefined lines; interradials obsolete on the medial portion. 

Incrementals, fine on the umbonal area, coarse on the anterior, 

posterior, and on the marginal portions. Lunule of holotype 

small, trending downward and forward. Pseudoescutcheon present. Hinge plate low and long, with a conspicuous sinuous basal 

line; nymph thin and long; ligamental pit deeply incised and 

long. Dentition well preserved on the holotype, consists of an 

anterior left cardinal (2a), trapezoidal with a blunted upper 

end, and a posterior cardinal (4b), thin anteriorly but slightly 

broadening ventrally. Interior of holotype with normally incised 

pedal and adductor muscle scars; pallial line entire; inner margins crenulated." (hertleini)

"Shell of medium size, thick, outline nearly circular; anterior, 

ventral and posterior margins evenly rounded, the postero-dorsal 

more gently curved. Shell moderately convex, with wide umbo, 

greatest convexity a little above the medial point of the disk; 

beak prosogyrate, distinctly low, placed at about the anterior 

one-third. Sculpture of 24 well-rounded ribs, (poorly preserved at 

the beak on the holotype), consisting of 16 wide, simple ribs in 

the antero-medial area becoming nearly obsolete below the 

middle of the disk, and 8 ribs on the posterior area 3 on the 

weak umbonal ridge, well defined and wide, 5 at the posterodorsal margin thin, crowded, becoming obsolete 15 mm. beyond 

the beak; interradials present throughout except in the medial 

one-third of the marginal part of the shell; incrementals faint 

and crowded, but fairly strong ventrally; periodic growth stages 

(annual rings) marked by deep incisions. Lunule small, convex, 

deeply inset. Pseudoescutcheon and nymph not well preserved in 

the holotype. Hinge low and short with a distinctly sinuous ventral margin; dentition consisting of a small, laminar right anterior cardinal (3a), a sharply triangular, curved medial cardinal 

(3b), and a thin right posterior cardinal (5b), not well preserved. 

Muscle scars and pallial line slightly incised; pedal scar somewhat more stongly defined; pallial line entire, relatively far 

away from the ventral margin. Inner margin with unusually 

deep crenulations." (oregonensis)

Holotype. UCMP 31450; of hertleini UCMP 30415; of oregonensis CAS/SU 8009; CASG 66529.01.

Type locality. UC 7004. Ventura County, Calif. Llajas Formation, Eocene. Of hertleini UC 3990, San Diego County, Calif. 

Rose Canyon Shale of Hanna (1927), Eocene. Of oregonensis 

"Bluffs along Little River at junction with North Umpqua River, 

Glide, Roseburg Quad., Douglas Co., Oregon." Umpqua Group, 

Lookingglass Formation of Baldwin (1974), Eocene.
E22 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Supplementary description. "Lunule convex, deeply inset, the 

right twice as large as the left; lunular groove trending downward and backward. Pseudoescutcheon well defined by a wide 

plate delimited by a grooved line on the dorsal side. Nymph long 

and narrow, somewhat alate at its posterior end, at the anterior 

it embraces a shallowly incised groovelike ligamental pit. Hinge 

plate high with a sinuous basal margin; dentition of the right 

valve consists of a strong plate-shaped, anteriorly slightly convex 

anterior cardinal (3a); a scimitar-like, strongly curved medial 

cardinal (3b), showing an incised groove in the upper part of the 

anterior face; and a long, thin, cordlike posterior cardinal (5b), 

the left valve has a high, curved, cuneate anterior cardinal (2), 

with an oblique cord in the upper part of the posterior face to 

correspond to the groove in 3b; and a thin, curved posterior cardinal (4b) which slopes slightly at the ventral end. Pedal and 

adductor muscle scars shallowly incised, the posterior scar remote from the hinge; pallial line entire, rather near the margins. 

Inner margin faintly crenulated." (Verastegui, 1953, p. 28-29)

"V. hornii calafia is characterized by its circular to 

subquadrate outline and by the presence of 24 radial ribs***" 

(Givens, 1974, p. 47)

Comparison. "Stewart's subspecies (calafia) differs only in 

small details from the rounded varieties of V. hornii (Gabb) 

found in the type Tejon. The anterior dorsal margin of the 

former is fuller, giving the beaks a lower appearance, and the 

ribs are slightly less rounded." (Turner, 1938, p. 50)

"V. lutmani Turner from the lower part of the Umpqua formation appears to be ancestor of V. calafia. The two species differ 

somewhat in outline, V. lutmani being more subquadrate, but 

the pattern of the hinge is almost identical in both." (Verastegui, 

1953, p. 29-30)

"The subspecies calafia resembles the species hornii in number of ribs and ornamentation more than does the subspecies 

lutmani. The specimens of calafia from southwest Oregon have 

the radiating ribs less rounded than in the species hornii and 

the general outline of the shell is more orbicular than in the 

subspecies lutmani." (Weaver, 1942, p. 135)

Geographic range. Southern Oregon and southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: Llajas Formation (Keen 

and Bentson, 1944; Verastegui, 1953; Squires, 1984) and Rose 

Canyon Shale (Hanna, 1927).

Venericardia (Pacificor) calafia gabbi Verastegui 

Plate 4, figures 2, 6, 8, 10

Cardita planicosta Lamarck. Conrad, 1855, p. 321, pi. 2, fig. 6.

Not Cardita planicosta Lamarck, 1801. 

Venericardia hornii (Gabb). Hanna, 1925, p. 286-287, pi. 39,

figs. 1, 2. Anderson and Hanna, 1925, p. 174, pi. 4, fig. 1. 

Venericardia (Pacificor) gabbi Verastegui, 1953, p. 30-31, pi. 19,

figs. 1, 5, 6.

Original description. "Shell large, thick, subquadrate in outline, the anterior margin broadly rounded, the ventral gently 

curved, the postero-ventral truncate, the postero-dorsal slightly 

arched. Umbo inflated, broadly convex, umbonal ridge inconspicuous but defined by a sudden change from coarse to fine ribs; 

beak prosogyrate, low, full, placed at about the anterior onefourth. Sculpture consists of 23 ribs, 8 in the anterior area, wide, 

terraced and beaded in typical Pacificor manner; in the medial 

portion 6 ribs widen ventrally away from the umbo; in the posterior portion 9 narrow ribs, the 4 nearest the cardinal margin less 

distinct but wider; interradials on the beak channeled, becoming 

linear, and persisting to the margin except in the medial-ventral

area; incrementals fine in the umbonal area and coarse in the 

anterior and posterior portions. Lunule cordate, convex, anteriorly trending downward and slightly backward. Pseudoescutcheon 

distinct, wide. Hinge plate low and long; nymph triangular, long; 

ligamental pit elongate, deeply incised; dentition consists of a 

laminar anterior right cardinal (3a); a scimitar-like medial cardinal (3b) with a wide base, elongate anteriorly; and a cordlike, 

short posterior right cardinal (5b) on a wide nymphal body. Interior of the holotype concealed by matrix."

Holotype. GAS 685; CASG 245.01.

Type locality. Grapevine Canyon, Kern County, Calif. Tejon 

Formation, Eocene.

Supplementary description. "Venericardia gabbi is characterized by its subquadrate outline and by its strongly convex 

umbo." (Verastegui, 1953, p. 30)

Comparison. "It [gabbi] differs from V. hornii (Gabb) in its outline, as the original Gabb specimen is elongate and obliquely ovate 

and V. gabbi has a quadrate outline accentuated by a sharp truncation on the posterior ventral margin." (Verastegui, 1953, p. 30)

Geographic range. Southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: Tejon Formation 

(Verastegui, 1953).

Venericardia (Pacificor) clarki clarki Weaver and Palmer 

Plate 5, figures 4, 6

Venericardia planicosta Lamarck. Arnold, 1907, pi. 38, figs. 1, la.

Arnold, 1910, p. 13, pi. 2, fig. 1. Not Venericardia planicosta

Lamarck, 1801. 

Venericardia planicosta hornii (Gabb). Waring, 1917, p. 95-96,

pi. 11, figs. 3-5. 

Venericardia clarki Weaver and Palmer, 1922, p. 19, pi. 9, figs. 4, 5;

pi. 10, fig. 8. Hanna, 1925, p. 287-288, pi. 36, figs. 3, 8; pi. 38,

figs. 2, 3; pi. 43, figs. 1, 2; pi. 44, figs. 1, 2. 

Venericardia hornii subsp. clarki Weaver and Palmer. Turner,

1938, p. 49 (in part), pi. 14, figs. 3, 5. Weaver, 1942, p. 274,

pi. 27, figs. 7, 9, 10, 17; pi. 33, fig. 6. 

Venericardia (Pacificor) weaveri Verastegui, 1953, p. 31, pi. 21,

figs. 3, 4. 

Venericardia (Pacificor) lisa Verastegui, 1953, p. 39, pi. 21,

figs. 1, 2. 

Venericardia (Pacificor) hornii (Gabb). Givens, 1974, p. 46, pi. 3,

fig. 3.

Original description. "Shell small and ovate; umbones small; 

anterior end slightly produced, sloping from the beaks at an 

angle of 20°, rounding into the ventral margin; ventral margin 

regularly rounded; posterior end rounded, passing from the ventral margin at about the same degree of convexity as the anterior end; surface ornamented with 18 to 20 very well developed 

radiating ribs with rounded interspaces about half the width of 

the rib; the median portion of the ribs is raised and rounded, the 

base forming a lower ridge on each side of the ribs, giving them 

a tripartite character; the median, raised portion of the ribs is 

ornamented by fine nodes or pustules which occur on all the ribs 

on very young shells, and on the umbonal region and the anterior end of most of the shells; the ribs on the posterior end of the 

older specimens become broader and the pustulate condition 

obliterated; inner margin fluted." (clarki)

"Shell large, thick, outline round to subquadrate, the anterior and ventral margins evenly rounded, the postero-ventral 

somewhat attenuate and the posterior margin slightly truncate. Umbo convex, inflated; umbonal ridge weak, ribs narrower on posterior slope; beak distinctly low, at about the anterior
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E23

two-fifths. Sculpture, characteristic of Pacificor, consisting of

21 rounded ribs relatively less perceptible in the ventral portion of the medial area; 14 ribs in the antero-medial area typically fasciculate tripartitely ribbed showing a distinct 

nodose ornamentation near the beak and on rib crests; 7 ribs 

in the posterior area less prominent, thin and crowded. Interradials persistent to the margins, V-shaped on the beaks, become linear in the rest of the shell. Incremental fine on the 

disk, coarse on the anterior portion. Lunule cordate, deeply inset; lunular groove wide, vertical. Pseudo-escutcheon well defined; hinge plate long and low with a sinuous basal margin; 

ligamental groove and ligamental pit deep, the latter deeply 

excavated. Dentition of the right valve of the holotype consists 

of a small, laminar anterior cardinal (3a); with a triangular, 

pyramidal anterior cardinal (2), and a thin, curved posterior 

cardinal (4b). Pedal and adductor muscle scars well incised; 

pallial line at a moderate distance from the margins. Inner 

margin with wide crenulations." (weaveri)

"Shell large, outline subquadrate to ovate, the anterior margin 

passing into the ventral in an evenly rounded arc, the posteroventral margin attenuate, the posterior slightly curved; umbonal 

region inflated; beaks low, placed at the anterior one-third. 

Sculpture (not well preserved in the holotype) consists of 20 to

22 simple, rounded ribs. Ribs almost obsolete in the ventral part 

of the medial portion of the shell, but distinct to the margin in 

the anterior and posterior areas. Interradials linear, evanescent 

in the medial portion and near the ventral area. Incremental 

fine, threadlike. Lunule cordate, small; lunular groove wide, 

trending downward and slightly forward. Pseudoescutcheon 

present. Hinge plate low and long. Nymph long; ligamental pit 

in front of the nymph deeply incised; anterior right cardinal (3a), 

laminar, small; a medial (3b) strong, curved forward, with a long 

basal margin; a posterior cardinal (5b) thin, cordlike; the left 

valve with a small trigonal, elongate anterior cardinal (2) and a 

thin, curved posterior cardinal (4b). Pedal and adductor muscle 

scars small and shallowly incised. Inner margin crenulate." (lisa)

Holotype. UW 169; of weaveri CAS/SU 8024; CASG 66530.01; 

of lisa CAS/SU 8023; CASG 66531.01.

Type locality. UW 169 from the north bank of Cowlitz River, 

near the bend in sec. 28, T. 11 N., R. 2 W., Little Falls, Lewis 

County, Wash. Cowlitz Formation, Eocene; of weaveri Southeast 

bank of Stillwater Creek, 1 1A miles [2 km] NW of Vader, Wash., 

Cowlitz Formation, Eocene.; of lisa Bluffs along Olequa Creek at 

Old Ainslee Mill, T. 11 N., R. 2 W., Lewis County, Wash. Cowlitz 

Formation, Eocene.

Supplementary description. "The diagnostic features of V. 

weaveri are rounded to subquadrate outline, rounded ribs, and 

the subcuneate shape of the medial cardinal (3b)." (Verastegui, 

1953, p. 30)

Comparison. "V. weaveri***h&s fewer ribs (by two or three) 

[than V. gabbi} and***the basal margin of its medial cardinal 

(3b) is narrower. The latter difference may be due to the smaller 

size of the compared holotype." (Verastegui, 1953, p. 32)

Geographic range. Washington and southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: "questionably 'Coldwater"' 

(Verastegui, 1953), and Gaviota (Weaver and Kleinpell, 1963) 

Formations.

Venericardia (Pacificor) hornii (Gabb) 

Plate 5, figures 17, 18

Cardita hornii Gabb, 1864, p. 174 (in part), pi. 24, fig. 157. 

Gabb, 1869, p. 187-188 (in part).

Venericardia hornii (Gabb). Hanna, 1925, p. 286-287 (in part),

pi. 37, fig. 5; pi. 38, fig. 1; not pi. 39, figs. 1, 2 (=V. (P.) gabbi

Verastegui). 

Venericardia (Venericor) hornii (Gabb). Stewart, 1930, p. 165-

168, pi. 11, fig. 1. 

Venericardia hornii clarki Weaver and Palmer. Turner, 1938,

p. 49 (in part), pi. 14, fig. 1. 

Venericardia hornii (Gabb) clarki Weaver and Palmer. Weaver

in Weaver and Kleinpell, 1963, p. 153, pi. 32, fig. 2; pi. 27,

fig. 8. Not Venericardia clarki Weaver and Palmer, 1922. 

Venericardia (Pacificor) hornii (Gabb). Verastegui, 1953, p.

33-35, pi. 18, figs. 1-7; pi. 19, fig. 7. Givens, 1974, p. 46-47,

pi. 3, fig. 3. 

Venericardia (Pacificor) lisa Verastegui. Weaver and Kleinpell,

1963, p. 200 (in part), pi. 33, fig. 5. Not Venericardia

(Pacificor) lisa Verastegui, 1953.

Original description. "Shell large, thick, convex, subquadrate, 

oblique; beaks prominent, anterior, subterminal; cardinal margin 

broadly arched, sloping slightly, and uniting with the posterior 

end with a regular curve; base broadly rounded, most prominent 

in the middle, from which point it runs upwards rapidly towards 

the anterior end, which is broadly and regularly curved; posterior end obliquely subtruncated, angular below. Surface marked 

by twenty-two broad rounded ribs, a little the smallest posterior 

to the umbonal angle; these ribs are somewhat flattened above, 

especially towards the base, have acute interspaces, and are 

crossed by numerous coarse, irregular lines of growth. Hinge 

very thick, robust, and resembling that of C. [ardita] planicosta 

of the Eocene."

Lectotype. ANSP 4558 (Stewart, 1930).

Type locality. Live Oak Canyon (LouElla Saul, written commun., 1989) near Fort Tejon [Kern County, Calif.]. Tejon Formation, Eocene.

Supplementary description. "Typical Venericardia hornii is 

characterized by an obliquely ovate outline, a pointed to sharply 

rounded posteroventral margin, and 20-22 rounded radial ribs." 

(Givens, 1974, p. 47)

Geographic range. Oregon(?); southern California. 

Geologic range. Eocene.

Occurrence in California. Eocene: Coldwater Sandstone 

(Givens, 1974), Gaviota (Clark and Anderson, 1938), and Tejon 

(Dickerson, 1915; Keen and Bentson, 1944) Formations.

Venericardia (Pacificor) aragania joaquinensis (Vokes) 

Plate 6, figures 1-10; plate 8, figure 3; plate 9, figures 17, 19

Megacardita (Venericor) hornii (Gabb) joaquinensis Vokes, 1939,

p. 69-70, pi. 8, figs. 1, 2; pi. 9, figs. 1,2. 

Venericardia (Leuroactis) joaquinensis (Vokes). Verastegui, 1953,

p. 60-61, pi. 11, figs. 1-4; pi. 12, figs. 4-6. 

Venericardia (Pacificor) aragonia joaquinensis (Vokes). Saul,

1983, p. 76, pi. 2, figs. 7, 8. 

Venericardia ionensis Waring. Hanna, 1925, p. 42, pi. 42, figs. 1,

2. Not Venericardia ionensis Waring, 1914. 

Venericardia (Leuroactis) schencki Verastegui, 1953, p. 50-51,

pi. 4, figs. 6-8. 

Venericardia (Leuroactis) alisoensis Verastegui, 1953, p. 52-53,

pi. 10, figs. 1-3. 

Megacardita (Venericor) aragonia (Arnold and Hannibal) smileyi

Vokes, 1939, p. 67-68, pi. 6, figs. 1-3. 

Venericardia (Leuroactis) smileyi Vokes. Verastegui, 1953, p. 55-

56, pi. 10, figs. 4, 5. 

Venericardia (Leuroactis) vokesi Verastegui, 1953, p. 61-62,

pi. 14, figs. 1-3.
E24 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Original description. "Shell large, heavy, variable in shape; 

umbos prominent, inflated, anterior; posterior cardinal margin 

convex, rounded, ventral nearly straight, anterior broadly rounded ventrally but quite sharply rounded dorsally, straightening 

out to the small, deeply impressed lunule; sculpture consisting of 

21 subobsolete radial ribs appearing as low rounded waves on an 

otherwise smooth surface; hinge-plate large; posterior cardinal 

on the left valve long, thin, strongly curved; anterior cardinal 

short, thin, small; nymph-plate strong, appressed to the posterior cardinal at the anterior end."(joaquinensis')

"Shell large, thick, umbo narrow, convex, elongated diagonally 

and twisted forward; anterior margin evenly rounded, ventral 

margin slightly curved, posterior margin truncate; beak 

prosogyrate, at about the anterior one-third. Ribs 23, broadly 

rounded in the adult, in the young stage flat-topped, separated 

by narrow U-shaped interradials gradually becoming linear incisions; 16 ribs on the antero-medial portion, 7 compressed cordlike ribs on the posterior area, those nearest the posterior 

margin less discernible. Incrementals faint, distinctly wavy 

about 3 cm. from the beak become more sharply defined and 

threadlike near the ventral margin. Lunule deeply inset, convex, 

bordered by a deeply incised lunular groove. Escutcheon present. 

Ligamental groove well defined. Hinge plate very short and high 

with a straight ventral margin. Anterior cardinal (3a) broken in 

holotype but apparently placed vertically; socket (2') unusually 

deep, almost vertical, curving forward; medial cardinal (3b) very 

prominent, somewhat twisted forward, with a short basal margin and a knife-edged upper end; socket (4b') narrow, deep 

throughout its length; posterior cardinal (5b) wanting. Interior 

not well preserved; pedal muscle scar shallow; adductor muscle 

scars deeply incised; pallial line distant from the margin. Inner 

margin distinctly crenulate." (schencki)

"Shell large, heavy, with prominent umbos; posterior broadly 

rounded from umbo to posterior ventral edge where quite 

angulate, the ventral margin broadly rounded to the anterior 

cardinal edge, the shell there rounding sharply to the straight 

anterior cardinal margin; lunule small, deeply impressed; escutcheon elongate, well developed; surface with 21 rounded 

subobsolete ribs separated by narrow linear interspaces, the posterior 5 ribs narrower and less well developed than those on the 

rest of the valve; right valve of the hinge with a large trigonal 

and curved cardinal; left valve with a small elongate curved posterior cardinal, the posterior cardinal broad ventrally." (smileyi)

"Shell large, thick, cordate, obliquely elongate in outline; anterior and posterior margins attenuate, ventral very gently curved, 

and postero-dorsal gently arched. Umbo convex and umbonal 

ridge even less sharply defined than in V. joaquinensis; beak 

prominent, prosogyrate, placed at about the anterior one-fourth. 

Sculpture consisting of 22 broadly rounded ribs; 14 simple ribs 

well defined in the upper one-third of the shell, becoming inconspicuous and giving place to fine wavy incrementals, which become coarse with age; on the posterior area eight weak ribs, 

relatively more discernible than the anterior ones and traceable 

to the ventral margin. Interradials linear in the early part of the 

shell, becoming obsolete, represented over most of the shell by 

weakly defined shallow furrows. Lunule deeply inset, the right 

part three times as large as the left; lunular groove trending 

downward and backward. Escutcheon well defined by the hingecord. Hinge rather low and short, with a straight ventral margin; nymph narrow, long; ligamental pit shallowly incised; 

dentition strong, consisting in the right valve of a short, small 

anterior cardinal (3a); a cuneate, elongate medial cardinal (3b) 

slightly curved forward; and a long posterior cardinal (5b); the 

figured holotype (left valve) with an anterior cardinal (2) curved 

upward and forward, elongate and truncate at the upper end,

and a curved, long and high posterior cardinal (4b). Other inner 

characters concealed by matrix." (vokesi)

Holotype. UCMP 15616; of schencki CAS/SU 8003, CASG 

66532.01; of alisoensis UCMP 30176; of vokesi UCMP 15618; of 

smileyi UCMP 15626.

Type locality. UC 4170. Kings County, Calif. Avenal Sandstone, Eocene; of schencki: About 2 miles [3 km] northeast of 

Simi Peak, Simi Hills, Camulos quadrangle, Ventura County, 

Calif. Santa Susana Shale of Verastegui (1953), Eocene; of 

alisoensis UC 7019, Los Angeles County, Calif. Llajas Formation, Eocene; of vokesi Two thousand feet [610 m] east and 500 

feet [150 m] north of SW corner sec. 17, T. 23 S., R. 17 E., half a 

mile [1 km] east of Big Tar Canyon, Cholame quadrangle, Reef 

Ridge sheet, Kings County, Calif. Avenal Sandstone, Eocene; of 

smileyi UC 672. Fresno County, Calif. Domengine Formation, 

Eocene.

Supplementary description. "The principle [sic] variation in 

this species is in the height-length ratio. The general features of 

the outline, notably the shape of the anterior and posterior 

ends, are constant and appear to be characteristic." (Yokes, 

1939. p. 70)

Comparison. "This subspecies may be distinguished from 

typical M.[egacardita] hornii (Gabb) and M. hornii clarki 

(Weaver and Palmer) by the obsolete character of the ribbing. It 

differs from M. aragonia (Arnold & Hannibal) in being less 

angulate at the posterior ventral margin, more sharply rounded 

anteriorly, and in having lower, more massive umbos. It differs 

from other described forms of Megacardita in both shape and 

character of ribbing." (Yokes, 1939, p. 70)

Comments. Venericardia (Pacificor) aragonia aragonia 

(Arnold and Hannibal) does not occur in the Californias; it is 

restricted to Oregon.

Geographic distribution. Middle and southern California.

Geologic distribution. Paleocene and Eocene.

Occurrence in California. Eocene: Avenal Sandstone 

(Kappeler and Squires, 1984), Domengine (Yokes, 1939) and 

Llajas (Squires, 1983; Saul, 1983) Formations, Muir Sandstone 

(Weaver, 1953), and Santa Susana Shale (Verastegui, 1953).

Venericardia (Pacificor) clarki popenoei Verastegui 

Plate 9, figure 7, 15

Venericardia (Leuroactis) popenoei Verastegui, 1953, p. 62-63,

pi. 22, figs. 1-3. 

Venericardia (Pacificor) lisa Verastegui. Weaver and Kleinpell,

1963, p. 200 (in part), pi. 33, figs. 4, 7.

Original description. "Shell large, thick, subquadrate in outline, with an almost horizontal antero-dorsal margin; the anterior margin evenly rounded toward the ventral margin; the 

antero-dorsal end sharply rounded to subangular. Umbonal convexity perceptibly flattening toward the anterior margin. Beak 

prosogyrate, low, placed at about the anterior one-third. 

Sculpture** ""consists of 21 ribs, simple, flat-topped in the early 

stage, then rounded until the shell is 35-40 mm. high, and finally become almost obsolete; differentiated as follows: 14 ribs 

on the antero-medial portion and 7 ribs in the posterior area, 

not so wide, but slightly more conspicuous. Interradials Ushaped on the tip of the umbo, become linear and gradually disappear, their position still marked by the wavy pattern of 

incrementals. Growth lines or incrementals distinct in the holotype, fine in the young stage but become coarse with age. Lunule 

of holotype (left valve) narrow and high; lunular groove well incised, trending downward and forward. Escutcheon present and 

distinctly defined by the escutcheonal cord. Ligamental groove
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E25

wide and deep. Nymph thin and short; ligamental pit long, incised and rough. Hinge plate rather short and low with an almost straight ventral margin. Dentition (left valve) consists of a 

bean-shaped anterior left cardinal (2) isolated from the lunular 

arch, a triangular socket (3b') wide to accommodate a large 

trigonal cardinal (3b) (a distinctive character of this subspecies), 

and a thin, high posterior cardinal (4b) slightly broadened ventrally. Pedal muscle scar small, adductor muscle scars shallowly 

incised. Pallial line entire, distant from margin, apparently represented by a band of transverse rugosities. Inner margins 

crenulate."

Holotype. UCMP 15689.

Type locality. UCLA-581. "East side of main branch of 

Sespe Gorge, Ventura Co., California." "Coldwater" Formation, 

of Verastegui (1953) Eocene.

Supplementary description. The ribs are noded, sharply 

angled, and probably tripartite, but abrasion and recrystallization on the holotype have obscured details (LouElla Saul, written commun., 1989).

Comparison. V. popenoei can be distinguished from V. 

joaquinensis by the slight concavity in the anterior area of the 

shell and by the wider trigonal socket. (Verastegui, 1953)

"Venericardia (P.) popenoei is proportionately higher than V. 

(P.) joaquinensis and has fewer ribs" (LouElla Saul, written commun., 1989).

Geographic range. Southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: "Coldwater" (Verastegui, 

1953), Sacate (Weaver and Kleinpell, 1963) Formations; Eocene 

and Oligocene: Gaviota Formation (Weaver and Kleinpell, 1963; 

Verastegui, 1953).

Subgenus VENERICOR Stewart, 1930

Obliquely subtrigonal; immature ribs angular and spaced 

evenly, in adults flat and low, approximate, and finally vanishing; lunule depressed.

Geographic range. Europe, North America.

Geologic range. Paleocene and Eocene.

Comments. Figure 3 shows the phylogeny of Venericor in the 

eastern Pacific.

Venericardia (Venericor) venturensis Waring 

Plate 8, figures 1, 2, 4, 5, 7, 9, 11, 14

Venericardia planicosta venturensis Waring in McLaughlin and

Waring, 1914, map folio, fig. 12. Waring, 1917, p. 80, pi. 11,

figs. 6, 7, 9. 

Venericardia venturensis Waring. Hanna, 1925, p. 284, pi. 37,

figs. 1-4. Stewart, 1930, p. 165. Schenck and Keen, 1950,

pi. 19, fig. 5. 

Venericardia (Venericor) venturensis Waring. Keen and Bentson,

1944, p. 120. Verastegui, 1953, p. 45-47, pi. 3, figs. 1-4; pi. 4,

fig. 5. Zinsmeister, 1983, pi. 1, fig. 21. 

Venericardia (Venericor?) venturensis Waring. Saul, 1983, p. 79,

appendix 2, pi. 1, fig. 4 [explanation for plate in error]. 

Venericardia (Venericor) simiana Verastegui, 1953, p. 47-48,

pi. 4, figs. 1-4.

Original description. "Shell large, thick, cordate, deeply convex, altitude greater than the length; beaks large, turned forward, nearly touching; lunule small; anterior cardinal margin 

deeply excavated in angle; posterior cardinal margin deeply 

grooved and broadly convex; posterior margin convexly truncate;

surface ornamented by 25-30 large, square shouldered ribs, 

which are strong clear to the margins, with deep squared 

interspaces; posterior ribs narrow and indistinct; entire surface 

marked by wrinkled lines of growth. Locality 4, L.S.J.U. Pal. 

Coll." (venturensis)

"Shell large, thick, cordate in outline, anterior margin broadly 

rounded, the ventral gently curved, sharply rounded at the 

postero-ventral end, passing into truncated posterior; umbones 

slightly convex; posterior area set off both by the umbonal ridge 

and by the difference in sculpture; beaks low, at about the anterior one-fourth. Ribs 28-30; 19 in the antero-medial area persistent, V-shaped at beaks flat-topped throughout the surface of the 

disk and separated by U-shaped interradials. Lunule deeply set, 

convex, pointing downward and backward, bordered anteriorly 

by a lunular groove; in the left valve the lunular groove ends in 

a pustule corresponding to a small depression on the right valve. 

Escutcheon not defined. Wide ligamental groove and elongated 

nymph, with a deep triangular ligamental pit at its anterior end. 

Hinge heavy, low, long, with a distinctly sinuous basal margin; 

dentition strong and prominent; right anterior cardinal (3a) 

laminar, vertical, minute; a middle cardinal (3b) curved, scimitar-like, with a dorsal edge sharply grooved ventrally; posterior 

cardinal (5b) thin, almost undifferentiated; paratype No. 8002 

with an elongate, cuneate left anterior cardinal (2) and a high, 

thin, posterior (4b). Pedal scars small; adductor muscle scars 

concealed by matrix in all specimens examined; pallial line remote from the strongly crenulate margin." (simiana)

Holotype. CAS/SU 159; CASG 61667.08; of simiana CAS/SU 

8001; CASG 66533.01.

Type locality. SU 2697. Ventura County, Calif. Santa Susana 

Formation of Zinsmeister (1983), Paleocene; of simiana SU 2697, 

Ventura County, Calif. Santa Susana Formation, Paleocene.

Comparison. "Venericardia venturensis Waring may easily be 

distinguished from other Eocene Venericardia of the West Coast 

by its greater altitude in proportion to its length, and by the 

squareness of the radial ribs; it may be distinguished from Venericardia ionensis Waring by the radial ribs usually extending 

to the basal margin. All the individuals referred to this species 

have been found associated with Martinez fossils." (Hanna, 1925, 

p. 284)

Geographic range. Middle California to Baja California 

Norte.

Geologic range. Paleocene.

Occurrence in California. Paleocene: Santa Susana Formation (Waring, 1917; Kew, 1924; Verastegui, 1953; Zinsmeister, 

1983).

Venericardia (Venericor) vallecitosensis (Vokes) 

Plate 2, figures 3-5, 7

Megacardita (Venericor) vallecitosensis Vokes, 1939, p. 67, pi. 5,

figs. 10-12. 

Venericardia (Pacificor) vallecitosensis (Vokes). Verastegui, 1953,

p. 35-36, pi. 12, figs. 1-3. 

Megacardita (Venericor) hornii (Gabb) carlosensis Vokes, 1939,

p. 68-69, pi. 7, figs. 1-6. 

Venericardia (Venericor) carlosensis (Vokes). Verastegui, 1953,

p. 36-37, pi. 13, figs. 4-9.

Original description. "Shell large, heavy, almost circular in 

outline; umbos moderately inflated; surface with 23 radiating 

ribs, those on the central portion of the valve being planicostate 

and separated by flat-bottomed interspaces about two thirds as 

wide as the ribs; valve slightly angulate at the sixth rib from the 

posterior margin, the posterior ribs narrow, somewhat ridged
E26 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

and closer together, the anterior 5 or 6 ribs so interrupted by 

the growth-lines as to appear to be noded, and separated by 

interspaces wider than the ribs; growth-lines elsewhere on the 

shell not prominent; lunule small and inconspicuous; hinge-plate 

small, the central cardinal of the left valve comparatively small, 

trigonal in shape and somewhat posterior to the umbo; socket 

large, curved on both the anterior and posterior sides; posterior 

cardinal long, thin, and high; nymph-plate thin, high, so close to 

the posterior cardinal as to suggest a deeply grooved tooth."

"Shell moderately large, thin for the genus, variable in shape, 

quadrate to subtrigonal; umbos small, anterior; lunule minute, 

deeply impressed; escutcheon narrow, elongate; posterior end of 

shell obliquely angulate; surface with 21 radial ribs, the posterior 5 ribs small, rounded and weakly developed, separated by 

interspaces of equal width; the 3 ribs anterior to these strongly 

developed, persistently flat-topped, angulate at the edges, and 

separated by V-shaped interspaces of equal width; the 5 anterior 

ribs nodose in appearance due to the strength of the growthlines and separated by interspaces of equal width; the 8 ribs on 

the center of the valve minutely nodose in the early stages of 

development, flat-topped during adolescence, and rounded in the 

adult; hinge-plate small, the right cardinal curved, narrow and 

elongate, the nymph-plate long and grooved, the right socket 

narrow and obliquely set with a small tubercle on the anterior 

side; the left anterior cardinal small and subtriangular, the posterior cardinal long, thin, and curved, the nymph-plate long, low, 

and so closely set against the posterior cardinal as to appear to 

be a part of that tooth." (carlosensis)

Holotype. UCMP 15614; of carlosensis UCMP 15619.

Type locality. UC A-1022. San Benito County, Calif. 

Domengine Formation, Eocene; of carlosensis UC A-1017. Top of 

a small ridge 800' [244 m] SW of Hill 2,200 near center of south 

edge of sec. 16, T. 17 S., R. 12 E., Priest Valley quadrangle, San 

Benito County, Calif. Domengine Formation, Eocene.

Supplementary description. "The number of ribs is constant: 

of 40 specimens examined 4 had 20 ribs, 27 had 21, 8 had 22, 

and 1 had 23. This form occurs at but one locality***where it is 

associated with Pelecyora aeguilateralis (Gabb), Ostrea idriaensis 

Gabb, Loxotrema turrita Gabb, Potamides carbonicola Cooper, 

and Calyptraea diegoana (Conrad). These species suggest that 

the water was of less than normal salinity, which may be a possible explanation for the thin shell and the great variation in 

shape." (Vokes, 1939, p. 69)

Comparison. "The small umbo and general outline is very suggestive of Gabb's original figure of M.[egacardita] hornii, but the 

small hinge-plate with the narrow elongate right cardinal, and 

the character of the ribbing are distinctive." (Vokes, 1939, p. 69)

Geographic range. Middle California.

Geologic range. Eocene.

Occurrence in California. Eocene: Domengine Formation 

(Vokes, 1939; Keen and Bentson, 1944).

Subfamily CARDITESINAE 

Genus GLYPTOACTIS Stewart, 1930

Short trapezoidal, with high nodulose or echinate ribs; small, 

irregularly convex lunule extending under and slightly behind 

beaks.

Geographic range. North America, Europe, Africa.

Geologic range. Cretaceous to Miocene.

Comments. Figure 3 shows the phylogeny of Glyptoactis in 

the eastern Pacific.

Subgenus CLAIBORNICARDIA Stenzel and Krause, 

1957

More developed on both sides and with lower beaks than Glyptoactis (Glyptoactis); ribs triparite, posteriorly echinate; lunule 

less depressed.

Geographic range. North America, Europe.

Geologic range. Paleocene to Eocene.

Comments. Figure 3 shows the phylogeny of Claibornicardia 

in the eastern Pacific.

Glyptoactis (Claibornicardia) sandiegoensis (Hanna) 

Plate 1, figures 15, 19, 21; plate 7, figs. 15, 22

Cardita sandiegoensis Hanna, 1927, p. 283, pi. 37, figs. 1, 2, 8, 9. 

Venericardia sandiegoensis (M. Hanna). Stewart, 1946, table 1. 

Glyptoactis (Claibornicardia) sandiegoensis (Hanna, 1927). 

Givens and Kennedy, 1979, p. 95, table 1. Squires, 1987, 

p. 64, fig. 110.

Venericardia (Glyptoactis) mcmastersi Verastegui, 1953, p. 42- 

43, pi. 13, figs. 2, 3.

Original description. "Shell of moderate size, elongate-ovate; 

ventral margin broadly regularly rounded; anterior more 

sharply rounded; posterior obliquely truncated to slightly 

rounded; dorsal straight to slightly rounded; beak moderately 

prominent; surface concentrically striated by distinct growth 

lines; radially striated by fifteen to nineteen prominent ribs; 

posterior ribs rather sharp, separated by sharply rounded 

interspaces; the posterior ribs are only slightly terraced on either side; terracing becomes more prominent on the anterior 

half of the shell, so much so that the anteriormost ribs are 

nearly three separate ribs, each group of three ribs wider and 

separated by narrower shallow interspaces; from the beak to the 

posterior ventral point the shell is ventricose, less ventricose 

both to the anterior and to the posterior of this line; inner margin deeply crenulate; hinge plate narrow, typically carditiform. 

Dimensions. Cotype 30983: Altitude 33 mm., length 45 mm." 

(sandiegoensis)

"Shell small, quadrate in outline, anterior margin evenly 

rounded, the ventral slightly curved, the posterior distinctly 

truncated, making an angle of 90° with the ventral margin; 

postero-ventral and postero-dorsal ends sharply rounded to subangular, accentuating the quadrate outline of the shell. Umbo 

strongly inflated, curved forward, prosogyrate, with beak placed 

at about the anterior one-fourth. Umbonal ridge, delimiting the 

posterior area, defined by the change in the coarseness of the 

ribs. Sculpture similar to that of V. keenae, n. sp., consisting of 

21 well-developed ribs; 4 simple crowded ribs on the anterior 

portion followed on the medial portion by 9 ribs definitely terraced on both sides; 8 ribs on the posterior area simple, Vshaped; the crest of the ribs bears fine nodes which are 

conspicuous on the ventral area of the valve. Interradials Ushaped. Incremental sculpture fine. Lunule small, semicordate, 

trending forward and downward, with deeply incised lunular 

groove. Escutcheon narrow. Hinge plate low and long, with an 

arched ventral margin. Nymph thin; ligamental pit inconspicuous. Dentition consisting of pustule-like anterior left cardinal 

(2), broken off in the holotype; and a slender, long posterior cardinal (4b). Pallial line entire, closely placed to the margin. Inner margin strongly crenulate." (mcmastersi)

Types. Syntypes UCMP 30980-30983; holotype of mcmastersi 

CAS/SU 8011; CASG 66534.01.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E27

Type locality. UC 5062. San Diego County, Calif. Rose Canyon Shale of Hanna (1927), Eocene; of mcmastersi San Clemente 

Canyon, San Diego Co., California. La Jolla Group, Eocene.

Comments. Stewart (1930, p. 152) suggested that 

sandiegoensis might be a Glyptoactis.

Geographic range. Middle and southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: Avenal Sandstone 

(Stewart, 1946), Delmar Sand and Rose Canyon Shale (Hanna, 

1927), and Juncal Formation (Squires, 1987).

Glyptoactis (Claibornicardia) keenae (Verastegui) 

Plate 8, figures 6, 8, 10, 12, 13, 15

Venericardia (Glyptoactis) keenae Verastegui, 1953, p. 41-42, pi. 1,

figs. 1-5. Smith, 1975, p. 470, pi. 2, fig. 5.

Venericardia (Pacificor) argentea Verastegui, 1953, p. 25-26, pi. 1, 

figs. 10-14.

Original description. "Shell small, cordate-subquadrate in 

outline, anterior and ventral margins broadly rounded, the posterior truncated and the dorsal margin slightly arcuate; umbo 

strongly convex with the most prominent point above and 

slightly anterior to the mid-point of the disk; posterior area 

sharply delineated by a change in sculpture and radially depressed; beak prosogyrate, low and compact. Sculpture distinct, 

consisting of 30 ribs persistent throughout the entire surface of 

the shell; of these, the 4 anterior ribs crowded, thin, faintly fasciculate, (slightly terraced); the next 14 ribs conspicuously terraced, so that they appear to be tripartite with a central crest 

bordered on each side by smaller riblets (the central crest 

beaded with light funnel-shaped tubercules not discernible upon 

ribs of the umbonal area); the succeeding 4 ribs with a terraced 

face only on the posterior side; posterior area with 4 crowded Vshaped ribs; the remaining 4 ribs a little wider, with riblets on 

the posterior side. Interspaces at the anterior and posterior portions V-shaped; in the medial area, with deep U-shaped channels. Incrementals fine and sharp, more noticeable on the 

posterior area of the adult shell. Lunule small, distinctly convex, 

bounded by an incised lateral groove which in the left valve ends 

ventrally, with the walls of the trough forming a knob (the anterior pustule of Stewart). Escutcheon slightly discernible, bordered below by a cord. Ligamental groove narrowly incised. 

Nymph narrow and elongate. Ligamental pit not evident. Hinge 

plate low and short with a straight ventral border; dentition of 

the left valve consists of a nearly trigono-pyramidal anterior cardinal (2), isolated from the lunular plate; and a thin posterior 

cardinal (4b) broadens toward the ventral end. Pedal muscle 

scar small and shallowly incised; adductor muscle scars moderately incised, pallial line entire and remote from the ventral 

margin. Inner margins crenulate."

"Shell of medium size, inflated-ovate in outline with the ventral margin broadly rounded, umbones prominent, greatest inflation a little above the center of the disk the surface rounds off 

broadly in all directions, except toward the posterior slightly 

concave dorsal slope; beak prosogyrate, low and compact, placed 

at about the anterior one-third. Ribs 30 to 32; typical Pacificor 

sculpture (as described in the diagnosis of the subgenus). Posterior area with 10 ribs; the 5th nearest the dorsal margin wide, 

with one posterior riblet; the other 5 thin, crowded, V-shaped, 

with corresponding V-shaped interspaces. Interspaces in the medial portion squarely channeled, one-third the width of the ribs. 

Frontal rib crests show a beadlike appearance as in V. mulleri. 

Lunule small, convex, sloping forward, (not well preserved in the

holotype). Pseudoescutcheon present. Ligamental groove deeply 

incised; nymph long and wide; ligamental pit shallowly incised. 

Hinge plate low and short; dentition of the left valve with a 

strongly developed, scimitar-like anterior cardinal (2), projected 

over the medial plane, and a thin posterior cardinal (4b) which 

thickens gradually toward the ventral end. Pedal muscle scars 

normally incised. Adductor muscle scars and pallial line concealed by matrix." (argentea)

Holotype. CAS/SU 7992; CASG 66535.01; of argentea CAS/SU 

7995; CASG 66535.02.

Type locality SU 2073. Fresno County, Calif. Base of Lodo 

Formation, Paleocene; for argentea the same.

Geographic range. Middle California.

Geologic range. Paleocene.

Occurrence in California. Paleocene: Basal part of the Lodo 

Formation (Verastegui, 1953; Smith, 1975).

Glyptoactis (Claibornicardia} marksi (Verastegui) 

Plate 7, figures 17, 19

Venericardia (Glyptoactis) marksi Verastegui, 1953, p. 44, pi. 19, 

figs. 2-4.

Original description. "Shell small, thin, outline subcircular, 

the anterior and ventral margins evenly rounded, the posteroventral truncated, the postero-dorsal slightly arched. Umbo 

fairly convex, prominent, with the greater inflation in the middle 

of the disk; beak prosogyrate, heavy, full, placed at about the 

anterior two-fifths. Sculpture consists of 18 ribs strongly ornamented by fine closely spaced beads along the crests; of these, 

the 5 in the anterior area thin, simple, separated by wide Ushaped interspaces twice as wide as the ribs; the 8 medial ribs 

simple in the early umbonal area, but become terraced (tripartite) in the mature part of the shell; interspaces wide, U-shaped; 

the 5 ribs on the posterior area closely spaced and thin with 

interspaces V-shaped; incrementals fine, more visible on the flatbottomed interspaces. Lunule small, convex. Escutcheon wanting. Hinge rather high for the subgenus; dentition of the right 

valve consists of a small anterior cardinal (3a), a cuneate long 

medial cardinal (3b), and a slender posterior cardinal (5b). Interior of the holotype concealed by matrix except for the inner 

margin, which is strongly crenulate."

Holotype. CAS/SU 8021; CASG 66536.01.

Type localilty. SU 183. "East side of Live Oak Canyon, Kern 

Co., California." Live Oak Member of the Tejon Formation of 

Verastegui (1953), Eocene.

Comparison. "***V. marksi can be readily distinguished 

from V. domenginica by its heavier and less pointed beak, by 

its circular outline, and by the greater convexity of the shell." 

(Verastegui, 1953)

Geographic range. Southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: Cozy Dell Formation 

(Weaver and Kleinpell, 1963) and Live Oak Member, Tejon Formation of Verastegui, 1953.

Glyptoactis (Claibornicardia} domenginica (Vokes) 

Plate 7, figures 10, 12, 13, 16, 18, 20

Venericardia (Glyptoactis?) domenginica Vokes, 1939, p. 66, pi. 5,

figs. 7-9. 

Venericardia (Glyptoactis) domenginica Vokes. Verastegui, 1953,

p. 43, pi. 13, fig. 1. 

Glyptoactis domenginica (Vokes). Givens, 1974, p. 47.
E28 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

Glyptoactis (Glyptoactis) domenginica (Vokes, 1939). Squires,

1984, p. 46-47, figs. lOq-r. Squires, 1987, p. 63-64, fig. 109. 

Glyptoactis (Claibornicardia) domenginica (Vokes, 1939). 

Squires, 1988, p. 19, fig. 50.

Original description. "Shell small, moderately inflated, inequilateral, almost circular in outline; umbo small, high, prominent; lunule impressed; sculpture consisting of 17 radial, ridged, 

strongly beaded ribs, separated by round-bottomed interspaces 

slightly more than half as wide as the ribs, the ribs being finer 

and closer together on the posterior portion of the valve; posterior cardinal of the hinge in the right valve long, slender, 

curved, the anterior cardinal in the left valve reduced to a small 

rugosity bounding the anterior end of the large central socket, 

with a well-defined anterior lateral pustule."

Holotype. UCMP 15611.

Type locality. UC A-1219. Fresno County, Calif. Domengine 

Formation, Eocene.

Supplementary description. "This species is more typical of the 

subgenus Claibornicardia Stenzel and Kraus (in Stenzel et al., 

1957) than of the subgenus Glyptoactis Stewart (1930). Heaslip 

(1968:98, 110) compared these two subgenera and reported that 

only Claibornicardia had spinose ribs, and that it lacked the diagnostic tooth' that Glyptoactis had above the intersection of the 

lunule and the anterior point of the left posterior cardinal tooth. 

Glyptoactis (Claibornicardia) domenginica has spinose radial ribs 

and lacks the diagnostic 'tooth'." (Squires, 1988, p. 19.)

"***the specimens show the diagnostic 16 to 17 noded tripartite ribs that are finer and closer together on the posterior portion of the valve. The tripartite nature of the ribs also becomes 

less apparent posteriorly. "(Squires, 1988, p. 19)

Comparison. "V. domenginica differs from all the described 

western Eocene species referred to the Carditidae in size, shape, 

and character of the ribbing. It finds its nearest analogue in the 

group of V. acuticostata in the Lutetian-Bartonian of France." 

(Vokes, 1939, p. 66)

Geographic range. Middle and southern California.

Geologic range. Eocene.

Occurrence in California. Eocene: Domengine, Llajas, and 

Tejon Formations (Vokes, 1939); Juncal(?) Formation (Squires, 

1988).

Subfamily THECALIINAE 

Genus MILNERIA Dall, 1871

Narrowly trapeziform, very inequilateral, with two median 

posterior angulations, finely echinate ribs, concentric lines; 

beaks orthogyrous.

Geographic range. Middle California to Baja California Sur.

Geologic range. Pliocene to Holocene.

Habitat. Intertidally to 27 m, byssate and nestles on flat 

surfaces like the backs of Haliotis (Hertlein and Grant, 1972, 

p. 240); intertidally to 80 m (Bernard, 1983).

Milneria minima (Dall) 

Plate 9, figures 16, 18

Ceropsis minima Dall, 1871, p. 152, pi. 16, figs. 5, 6.

Milneria minima Dall. Hertlein and Grant, 1972, p. 234, pi. 43,

figs. 1, 2, 14. Coan, 1977, p. 384.

Original description. "Shell minute, trapeziform, white, with 

a thin brownish epidermis. Umbones prominent, 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."

Lectotype. USNM 63349 (Coan, 1974).

Type locality, "Habitat, nestling or burrowing in Haliotis 

rufescens, at Monterey, also dead on beach."

Comparison. '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***." (Hertlein and Grant, 1972, p. 234)

Geographic range. Living: Monterey, Calif., to Isla de Natividad, Baja California Sur.

Geologic range. Pliocene to Holocene.

Occurrence in the Californias. Pliocene: San Diego Formation 

(Hertlein and Grant, 1972); Pleistocene: unnamed strata in the 

Palos Verdes Hills, San Pedro, Calif. (Woodring and others, 

1946), and on San Nicolas Island (Vedder and Norris, 1963).

Habitat. Intertidally to 80 m in the eastern Pacific (Bernard, 

1983). Attaches to hard substrates by a byssus (Coan, 1977).

FOSSIL LOCALITIES

[Corrections and information not in the original description are in brackets: feet 

and miles are converted to the metric system, formations are cited as emended by 

later workers, where pertinent.]

California Academy of Sciences:

GAS 65. West bank of a small canyon 2 km NE of Barker's 

Ranch House [SE V*. sec. 32, T. 28 S., R. 29 E., Caliente 

quadrangle], Kern County, Calif. Temblor Formation.

CAS 244. In east bank of Live Oak Creek, 1.2 km from 

mouth, 4.8 km due east of mouth of Grapevine Canyon, 

Tejon quadrangle, Kern County, Calif. Tejon Formation. 

Los Angeles Natural History Museum:

LAM 305. 730 m east and 310 m south of NW cor. sec. 8, 

T. 19 S., R. 2 W., S.B.M., San Ysidro quadrangle, 1943 

ed. [San Diego County], Calif. San Diego Formation.

LAM 305c. Hills south of Tjjuana River at Palm City, Calif. 

"K" Ranch, exactly 290 ft [88m] from the U.S.-Mexican 

border fence. Southwest of Goat Canyon, at base of hill 

100 ft [31 m] W., 440 ft [134 m] S. of NE cor. sec. 8. 

Imperial Beach quadrangle, San Diego County, Calif. San 

Diego Formation.

Stanford University [These collections are now all in the 

California Academy of Sciences]:

SU 2073. Road cut just south of middle of section line 

between sees. 20 and 29, in sec. 29, T. 15 S., R. 12 E., 

opposite junction of Panoche and Silver Creeks, Panoche 

quadrangle, Fresno County, Calif. Basal part of Lodo 

Formation.

SU 2696. McCray wells [Oil Canyon, 3 miles [5km] north 

20° east of B.M. 961 at Santa Susana, Santa Susana 

quadrangle, Ventura County, Calif.]. Llajas Formation.

SU 2697. Simi Hills, [4.5 km ENE of Simi Peak, near head 

of east fork of Las Virgenes Canyon], Camulos quadrangle, 

Ventura County, Calif. Santa Susana Formation.
TERTIARY MARINE PELECYPODS: ERYCINIDAE THROUGH CARDITIDAE E29

University of California at Berkeley:

UC 672. South part of crest of Parson's Peak, SEVi, NVi, sec. 

24, T. 18 S., R. 14 E., Coalinga quadrangle, Fresno 

County, Calif. Domengine Formation.

UC 2033. South of Hill 651 about 400 m, 800 m west of 

Kirkers Creek, near west edge sec. 30, T. 2 N., R. 1 E., 

Mt. Diablo quadrangle, Contra Costa County, Calif. Kirker 

Tuff, Oligocene.

UC 3765. NWy4SWV4 sec. 24, T. 2 N., R. 18 W., 2,060 m E of 

Hill 2150, Simi Hills, Camulos quadrangle, Ventura 

County, Calif., Martinez Group of Dickerson (1914); Santa 

Susana Formation of Zinsmeister (1983).

UC 3990. On the east side of canyon in bottom of Rose 

Creek, 485 m east of "t" of "Soledad Mountain," La Jolla 

quadrangle, San Diego County, Calif.

UC 4170. West side of Big Tar Canyon, T. 23 S., R. 17 E., 

Cholame quadrangle, Kings County, Calif. Avenal Sandstone.

UC 5062. In sea cliff south of mouth of Soledad Valley, due 

west of midpoint between "P" and "u" of "Pueblo," La Jolla 

quadrangle, San Diego County, Calif.

UC 7004. Branch of Las Llajas Canyon just north of northernmost extent of 1,500-foot contour, Simi Valley (Santa 

Susana quadrangle), Ventura County, Calif. Llajas Formation.

UC 7019. West side of Aliso Canyon West, beds striking 

northwest and dipping west. Fossils occur in narrow 

lenses. Elev. 555 m. Los Angeles County, Calif.

UC A-1219. West side, near top of long ridge extending 

northwest of Hill 2126, on line between sees. 9 and 16, 

T. 19 S., R. 15 E., Coalinga quadrangle, Fresno County, 

Calif. Domengine Formation.

UC A-1022. 300 ft. [90 m] above mouth and 20 ft. [6 m] up 

north wall of small canyon entering San Carlos Creek, 

south edge of sec. 16, T. 17 S., R. 12 E., Priest Valley 

quadrangle [San Benito County, Calif.]. Domengine Formation, Eocene.

UC A-1233. West of Roseburg, Douglas County, Oreg. 

Umpqua Formation.

UC A-3582. Bahia Santa Inez, from 6-m terrace level extending from locality UC A-3581 to beach. Baja California 

Sur.

UC A-3670. Puerto Balandra, Isla Carmen, from sands at 

left end of outcrop and below base of coral reef, Baja California Sur.

GEOLOGIC FORMATIONS CITED FOR 

OCCURRENCE OF PELECYPODS

Family Erycinidae through Carditidae

Name Age

California:

Avenal Sandstone Eocene.

Capistrano Miocene and Pliocene.

Cebada Member, Careaga

Sandstone Pliocene. 

Cerros Shale Member, Lodo

Formation Paleocene. 

Coal Canyon Formation Paleocene.

Coldwater Sandstone or

"Coldwater" Formation Eocene. 

Cozy Dell Formation

or Shale Eocene. 

Delmar Sand Eocene.

Dip Creek Formation Late Cretaceous and Paleocene. 

Domengine Formation or

Sandstone Eocene. 

Elk River Formation Pleistocene. 

Fernando Formation Pliocene and Pleistocene. 

Foxen Mudstone Pliocene. 

Gaviota Formation Eocene and Oligocene. 

Graciosa Member, Careaga

Sandstone Pliocene. 

Juncal Formation Eocene. 

Kirker Tuff -Oligocene. 

La Jolla Formation or

Group Eocene. 

Live Oak Member, Tejon

Formation - Eocene. 

Llajas Formation Eocene. 

Lodo Formation Paleocene and Eocene. 

Lomita Marl Member,

San Pedro Formation Pleistocene. 

Martinez Formation

or Group Paleocene. 

Meganos Formation Paleocene and Eocene. 

Monterey Shale Miocene. 

Muir Sandstone Eocene. 

Pancho Rico Formation Miocene. 

Pico Formation Pliocene and Pleistocene. 

Rio Dell Formation Pliocene and Pleistocene. 

Rose Canyon Shale Eocene. 

Round Mountain Silt Miocene. 

Sacate Formation Eocene. 

San Diego Formation Pliocene. 

San Francisquito

Formation Paleocene. 

San Pedro Formation

or Sand Pleistocene. 

Santa Barbara Formation Pliocene and Pleistocene. 

Santa Susana Shale or

Formation Paleocene and Eocene. 

Saugus Formation Pliocene and Pleistocene. 

Sisquoc Formation Miocene and Pliocene. 

Tejon Formation Eocene. 

Timms Point Silt Member, San

Pedro Formation Pleistocene. 

Towsley Formation Miocene and Pliocene. 

Baja California peninsula:

Bateque Formation Paleocene(?), Eocene 

Comondu Formation Pliocene. 

Marquer Formation Pliocene. 

Oregon:

Cowlitz Formation Eocene. 

Umpqua Formation

or Group Eocene. 

Washington:

Cowlitz Formation Eocene.

Stratigraphic nomenclature used is that of the references cited 

in the text and does not necessarily accord with that of the U.S. 

Geological Survey.
E30 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORNIA

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INDEX

[Italic page numbers indicate major references to accepted taxa]

Abbott, R.T., cited, 4,10

quoted, 9 

Abstract, 1 

Acknowledgments, 4 

acuticostata, Venericardia, 28 

Addicott, W.O., cited, 14 

aequata, Aligena

nuca, 8

aequilateralis, Pelecyora, 26 

affinis, Byssomera (Byssomera), 5

Cardita, II

(Byssomera), 11; pi. 9

Carditamera (Byssomera), 11

Glans, 15

alaskana, Venericardia (Cyclocardia), 14 

Aligena, 5, 7

aequata nuca, 8

(Aligena) diegoana, 5, 7; pi. 1

cerritensis, 8

diegoana, 1, 8

laevis, 8 

(Aligena), Aligena

diegoana, 5, 7; pi. 1

alisoensis, Venericardia (Leuroactis), 23; pi. 6 

Anderson, P.M., quoted, 6 

aragonia, Megacardita, 24

Venericardia, 19

(Pacificor), 27; p\. 8 

aragonia, 18,24 

diabloensis, 17,18,20; pi. 5 

joaquinensis, 17,18, 23; pis. 6, 8,9

(Venericor)

smileyi, 23 

Avenal Sandstone, 24, 27

B

Bahia San Quint in, 6 

barbarensis, Cardita, 15

Cyclocardia, 15

(Cyclocardia), 12,75; pi. 5

Venericardia, 13,15 

Basterotella, 10 

(Basterotella), Basterotia

hertleini, 5, 70; pi. 9 

Basterotia, 5, 70

(Basterotella) hertleini, 5,70, pi. 9

calif arnica, 10

ecuadoriana, 10

hertleini, 10

peninsulars, 11 

Bateque Formation, 20, 21 

Bentson, Herdis, cited, 1 

Bernard, F.R., cited, 4, 6,7,9,10,11,12,14,15,16,

28 

borealis, Cardita

crebricostata, 14

Venericardia, 13 

Bornia, 5,8

(TemWorn/a,)

frankiana, 5, 8; pi. 3 

triangulata, 5,8; pi. 3 

Bramlette, M.N., cited, 13

quoted, 15 

Byssomera, 11 

(Byssomera)

Byssomera 

affinis, 5

Cardita

affinis, 11; pi. 9

CaraVtamera 

affinis, 11

calafia, Venericardia 

hornii, 21,22 

(Pacificor),2^1

calafia, 17,18, 27; pi. 3 

gaW», 17,18, 22; pi. 4 

lutmani, 17, 18, 20; pis. 2,4,5 

susanaensis, 17, 18, 79; pi. 1 

californica, Basterotia, 10 

Cardita, 13

Cyclocardia, 13

Cyclocardia), 12, 73; pi. 7

Venericardia (Cyclocardia), 13 

Catypfraea

diegoana, 26

Capistrano Formation, 6, 15 

CaraYfa,4, 5, 11

affinis, 11

barbarensis, 15

borealis crebricostata, 14

(Byssomera) affinis, 5, 11; pi. 9

californica, 13

(Cardita) superioris, 5, 77; pi. 4

hornii, 23

megastropha, 12

monilicosta, 13

occidentalis, 13

planicosta, 22

sandiegoensis, 26

(Strophocardia) megastropha, 12; pi. 7

superioris, 1 1

veneriformis, 16

ventricosa, 14 

"Cardita"veneriformis, 16 

(Cardita), Cardita

superioris, 5, 77; pL 4 

Carditamera (Byssomera) affinis, 1 1 

Carditesinae, 26 

Carditidae, 1, 11,28 

Cardium tikerensis, 12 

Careaga Sandstone, 7, 9, 13, 15, 16 

carlosensis, Megacardita (Venericor) hornii, 25

Venericardia (Pacificor) hornii, 32

Venericor (Venericor), 25 

Carpenter, P.P., quoted, 15 

catacta, Kellia, 5, 6, 7, 31 

Cebada Member, 7, 13, 15, 16 

Centrocardita, 15 

(Centrocardita), Glans

veneriformis, 12, 76; pi. 7 

Ceropsis minima, 28 

cerritensis, Aligena, 8 

Cerros Shale Member, 6 

chironi, Kellia laperousii, 7 

'

laperousii, 7

suborbicularis laperousii, 7 

cistula, Lasaea, 6 

Claibornicardia, 18, 28 

(Claibornicardia) Glyptoactis

domenginica, 17, 18, 27, 28; pi. 7

tee/we, 17, 18, 27; pi. 8

worfcw, 17, 18, 27, pi. 7

mcmastersi, pi. 7

sandiegoensis, 17, 18, 26; pis. 1, 7 

clarki, Megacardita hornii, 24

Venericardia, 22, 23 

norm/, 22, 23

c/arfc, 17, 18, 22; pi. 5 

popenoei, 17, 18, 24; pi. 9 

Coal Canyon Formation, 19 

Coan, E.V., cited, 10, 14, 15, 16, 28

quoted, 15 

Coldwater Formation, 23, 25

Sandstone, 23

Comondu Formation, 10, 11, 13 

compressa, Erycina (Pseudopythina), 10

Neaeromya (Orbitella), 5, 70; pi. 4

"Orbitella" 10

Pseudopythina, 10 

conspicua, Stenoplax, 9

(Cuneocorbula) swiftiana harrisi, 6

harrisi, 6, 7

uvasana, 6

Cowlitz Fonnation, 23 

Cozy Dell Formation, 27 

crebricostata, Cardita borealis, 14

Cyclocardia, 14

(Cyclocardia), 12, 74; pi. 7, 9 

crescentensis, Venericardia (Pacificor), 18 

(Cuneocorbula), Corbula

swiftiana harrisi, 6 

Cyclocardia 4, 12

barbarensis, 15

californica, 13 

crebricostata, 14 

(Cyclocardia)

barbarensis, 12, 75; pi. 5

californica, 12,73; pi. 7

crebricostata, 12, 74; pi. 7, 9

kirkerensis, 12; pi. 9

montereyana, 12, 73; pi. 7

occidentalis, 12, 73; pi. 9

ventricosa, 12, 74; pi. 9 

occidentalis, 13 

ventricosa, 14 

(Cyclocardia) 

Cyclocardia

barbarensis, 12, 75; pi, 5

californica, 12,73; pi. 7

crebricostata, 12, 74; pi. 7,9

kirkerensis, 72 ; pi. 9

montereyana, 12,73; pi. 7

occidentalis, 12, 73; pi. 9

ventricosa, 12, 74; pi. 9 

Ke/iericaraVa

alaskana, 14; pi. 9

californica, 13

D

Delmar Sand, 27

diabloensis, Venericardia (Pacificor), 20, 32

aragonia, 17, 18,20; pi. 5 

diegoana, Aligena, 7,8 

(Aligena), 5, 7; pi. 1 

Calytraea, 26 

Dip Creek Fonnation, 17 

Domengine Formation, 24,26, 28 

domenginica 

Glyptoactis, 27

(Claibornicardia), 17,18,27, 28; pi. 7 

Glyptoactis), 28 

Venericardia, 27, 28 

(Glyptoactis), 27 

(Glyptoactisl), 27 

Donax triangulata, 8 

Durham, J.W., cited, 4,11,12

quoted, 11 

durhami, Venericardia (Pacificor), 20; pi. 2

ecuardoriana, Basterotia, 10

Elk River Fonnation, 15

Emerson, W.K., cited, 11,12

Erycina (Pseudopythina) compressa, 10

Erycinidae, 1, 5

Fernando Formation, 13,14,15, 16

Fossil localities, 28

Foxen Mudstone, 13, 16

frankiana, Bornia (Temblornia), 5,8; pi. 3

G

gabbi, Venericardia, 22, 23

(Pacificor), 22

calafia, 17, 18, 22; pi. 4 

Gale, H.R., quoted, 15 

Gaviota Fonnation, 23, 25 

Geologic Formations, pelecypods in, 29 

Glans, 12, 75

affinis, 1 1

(Centrocardita) veneriformis, 12, 76; pi. 7

(Glans) subquadrata, 12, 75; pi. 5

minuscula, 15

subquadrata, 15 

(Glans), Glans

subquadrata, 12, 75; pi. 5 

Glyptoactis, 4, 17, 18, 26, 28 

''

domenginica, 17, 18, 27, 28; pi. 7 

tee/we, 17, 18, 27; pi. 8 

marfcsj. 17, 18, 27; pi. 7 

mcmastersi; pi. 7 

sandiegoensis, 17, 18, 26; pi. 1, 7 

domenginica, 27

E35
E36 PALEONTOLOGY OF CALIFORNIA AND BAJA CALIFORIA

(Glyptoactis) domenginica, 28 

phytogeny 

sandiegoensis, 27 

(Venericor)

vallecitosensis, 18 

ventwensis, 18 

(Glyptoactis) 

Glyptoactis

domenginica, 28 

Venericardia 

domenginica, 27 

keenae, 27 

marksi, 27 

mcmastersi, 26 

(Gtyptoacti&l), Venericardia

domenginica, 27

Gordon, Mackenzie, Jr., cited, 4, 6 

Gould, A.A., quoted, 14 

Graciosa Member, 9,13,16 

Grant, U.S., IV, cited, 4,6,7,10,14,16,28

quoted, 8,9,15 

Graysian Stage, 14

H

Hatiotis rufescens, 28 

Hanna, GD., quoted, 6 

harrisi, Corbula, 6, 7

(Cuneocorbula) swiftiana, 6 

Hertlein, L.G., cited, 4,6, 7,10,11, 12,14,16, 28

quoted, 8,9,16 

hertleini,Basterotia, 10

Basterotia (Basterotella), 5, 1O, pL9 

Venericardia (Pacificor) 21; pi 3 

hornii, Cardita, 23 

Megacardita, 24 

clarki, 24 

(Venericor) 

carlosensis, 25 

joaquinensis, 23 

Venericardia 

calafia,2\,22 

clarki, 22,23 

lutmani, 20,21 

planicosta, 22

(Pacificor) 17,18, 20, 22, 23; pi. 5 

carlosensis; pi. 2 

lutmani, 20 

susanaensis, 19 

(Ve/ier/cor), 23

I

Introduction, 1

ionensis, Venericardia, 23, 25

Isla San Martin, 6

joaquinensis, Megacardita (Venericor) hornii, 23 

Venericardia, 24,25

(Leuroactis), 23

(Pacificor) aragonia, 17,18, 23; pis. 6, 8,9 

Jones, GJ7., cited, 14,15 

Juncal Formation, 21, 27

K

Keen, A.M., cited, 1,4,6,10,11, 12

quoted, 8,10 

keenae, Glyptoactis (Claibornicardia), 17,18, 27;

pi. 8

Venericardia (Glyptoactis), 27 

Kellia, 5,6

catacta, 5, <5,7; pi. 1

ris, 5, 6, 7; pi.: 

laperousii, 5, 7; pi. 3

lajollaensis,

rotunda,!

suborbicularis, 7

uvasana, 5, 6,7; pi. 3 

Kelliidae, 1, 6 

kelseyi, Milneria, 28 

KirkerTuff, 13 

kirkerensis, Cardium, 12

Cyclocardia (Cyclocardia), 12; pi. 9

La Jolla Group, 27 

laevis, Aligena, 8 

lajollaensis, Kellia, 5, 6, 7; pi. 3 

laperousii, Chironia, 7

suborbicularis, 7

Kellia, 5,7; ?\. 3

chironi, 7 

Lasaea, 5

cistula, 6

purpurata, 6

rn&ra subviridis, 6

scalaria, 6

subviridis, 5, 6; pi. 1 

Lazaria

subquadrata, 15 

(Leuroactis), Venericardia

alisoensis, 23,36

joaquinensis, 23

popenoei, 24

schencki, 23, 36

smileyi, 23

votes/, 23

tora, Venericardia (Pacificor), 22,23,24 

Live Oak Member, 27 

Llajas Formation, 11,21,22, 24, 28 

Lodo Formation, 6,19, 27 

Lomita Marl Member, 15,16 

Lookingglass Formation, 21 

Loxotrema turrita, 26 

lutmani, Venericardia 20,22

/WWH, 20,21

(Pacificor), 20

ca/a/7a, 17,18,20; pis. 2,4,5 

Aornii, 20

M

marksi, Glyptoactis (Claibornicardia), 17,18,27; 

pi. 7

Venericardia, 27

(Glyptoactis), 27 

Marquer Formation, 11,12,13 

Martinez Formation, 19 

mcmastersi, Glyptoactis (Claibornicardia); pi. 7

Venericardia (Glyptoactis), 26 

Megacardita, 24

aragonia, 24

hornii, 24 

c/artt, 24

(Kewn'cor)

aragonia smileyi, 23 

hornii

carlosensis, 25 

joaquinensis, 23 

vallecitosensis, 25 

Meganos Formation, 20 

megastropha, Cardita, 12

Cardita (Strophocardia),12; pi. 12

Strophocardia, 5

Venericardia, 12 

Milneria, 17,28

tebeyi, 28

minima, 17,28, 39 

minima, Ceropsis, 28

Milneria, 17,2S; pi. 9 

minuscula, Glans, 15 

Miodon prolongatus, 16 

Miodontiscus,prolongatus, 12, 76; pi. 5 

monilicosta, Cardita, 13 

Montacutidae, 1,9 

Monterey Shale, 13

montereyana, Cyclocardia (Cyclocardia), 12, 73; 

PL7

Venericardia, 13 

Moore, R.C., cited, 1 

Morris, R.H., cited, 4,9 

Muir Sandstone, 24 

mulleri, Venericardia, 19

(Pacificor), 17,18,79; pi. 1 

My«t«a, 5,9

tumica, 9

(Rochefortia) tumida, 5,9; pi. 7 

Mytilus, 5,6

N

Neaeromya, 5,9

(Orbitella) compressa, 5, 70; pi. 4 

nelsoni, Venericardia (Pacificor), 17,18, 79; pi. 1 

nuca, Aligena aequata, 8

O

oblongus, Pristes, 9

Thecodonta (Pristes), 5,9; pi. 4 

occidentalis, Cardita, 13

Cyclocardia, 13

(Cyc/ocordVa), 12,73; pi. 9 

Olsson, A.A., cited, 1

quoted, 11,12

Orbitella, 10

"Orbitella" compresssa, 10

(Orbitella), Neaeromya compressa, 5, 70; pL 4

oregonensis, Venericardia (Pacificor), 21; pL 3

(Pacificor), 1,76, 18

aragonia

aragonia, 1 8, 24

diabloensis, 17, 18, 20; pi. 5

joaquinensis, 17, 18, 23; pis. 6, 8, 9 

argentea, 27, 38 

calafia,2\

calafia, 17, 18, 27; pi. 3

«oW»i, 17, 22; pi. 4

/Mlmaw, 17, 18, 20; pis. 2, 4, 5

susanaensis, 17, 79; pi. 1 

c/ortb'

c/ar*i, 17, 18, 22; pi. 5 

popenoei, 17, 

crescentensis, 18

pi. 9

diabloensis, 20, pi. 2

durhami, 20, pi. 2

«aW», 22

hertleini,2l,pl. 3

hornii, IT, 18, 22, 23; pi. 5 

carlosensis, pi. 2 

lutmani, 20 

susanaensis, 19

«sa, 22,23,24

lutmani, 20

MM/teri, 17,18, 79; pi. 1

wfaom, 17,18, 79; pi. 1

oregonensis, 21, pi. 3

popenoei, 25

smileyi, pis. 6, 9

susanaensis, 19

taliaferroi, 1,77,18; pi. 5

transversaria, 19

vallecitosensis, 25

vokesi, pis. 8,9

weavcn, 22, pi. 5 

Palmer, K.V.W., cited, 9 

Pancho Rico Formation, 13 

Pelecyora aequilateralis, 26 

peninsulare, Basteotia, 11 

phytogeny, Glyptoactis, 18

Venericardia, 18 

Pico Formation, 14 

planicosta, Cardita, 22 

Venericardia, 22

Aorn/j, 22

venturensis, 19,25 

popenoei, Venericardia, 25 

(Leuroactis), 24 

(Pacificor) clarki, 17,18, 24; pi. 9

popenoei, 25 

Pristes, oblongus, 9

(Pristes), Thecodonta oblongus, 5,9; pL 4 

Procedure, 1 

prolongatus, Miodon, 16

Miodontiscus, 12, 76; pi. 5 

Pseudopythina compressa, 10 

(Pseudopythina), Erycina compressa, 10 

Purpose and scope, 1 

purpurata, Lasaea, 6

References, 30

Rio Dell Formation, 10,14,15

(Rochefortia), Mysella

tumida, 5,9; pi. 9 

Rose Canyon Shale, 7, 21, 22, 27 

Roseburg Formation, 20 

Roth, Barry, quoted, 10 

rotunda, Kellia, 7 

Round Mountain Silt, 8 

rubra, Lasaea 6

subviridis, 6 

rufescens, Haliotis, 28

Sacate Formation, 25

Sakamoto, Kenji, cited, 4

San Diego Formation, 7, 8, 9,13, 14,16,28

San Francisquito Formation, 17

San Pedro Formation, 7,14,15, 16

Sand, 13 

sandiegoensis, Cardita, 26

Glyptoactis, 27
INDEX E37

(Claibornicardia), 17,18, 26; pis. 1,7

Venericardia, 26

Santa Barbara Formation, 13, IS, 16 

Santa Susana Formation, 19, 25

Shale, 20,24 

Saugus Formation, 13 

Saul, LouElla, quoted, 25 

scalaria, Lasaea, 6

schencld, Venericardia (Leuroactis), 23; pi. 6 

Semeloidea, 8

simiana, Venericardia (Venericor), 25; pi. 8 

Sisquoc Formation, 13 

smileyi, Megacardita (Venericor) aragonia, 23

Venericardia (Leuroactis), 23

(Pacificor), pis. 6,9 

Smith, A.G., cited, 4,6 

Sportellidae, 1,10 

Squires, R.L., quoted, 28 

Stanley, S.M., cited, 4 

Stenoplax conspicua, 9 

Stewart, R.B., cited, 27

quoted, 16

Strong, A.M., cited, 12 

Strophocardia megastropha, 5,11 

(Strophocardia), Cardiia

megastropha, 12; pi. 7 

suborbicularis, Chironia laperousii, 7

Kellia, 7

subquadrata, Glans, 15 

(G/o/w),12,75;pl.5

Lazaria, 15 

subviridis, Lasaea, 5, 6; pi. 1

Lasaea rubra, 6 

superioris, Cardita, 11

(CoroVfa)5,77;pl.4 

susanaensis, Venericardia (Pacificor), 19

ca/a/7a, 17,18,79;pl. 1

hornii, 19

swiftiana, Corbula (Cuneocorbula) harrisi, 6 

Systematics, Pelecypods, 5

taliaferroi, Venericardia (Pacificor), 1, 77,18; pL 5 

Tejon Formation, 6,22,23,27,28 

Tellimya tumida, 9 

Temblornia, 8 

(Temblornia), Bornia

frankiana, 5, 8; pi. 3

triangulata, 5, S; pi. 3 

Thecodonta (Pristes) oblongus, 5,9; pi. 4 

Thompson, T.E., cited, 4 

Timms Point Silt Member, 14,16 

Towsley Formation, 13 

transversaria, Venericardia (Pacificor), 19 

triangulata, Bornia (Temblornia), 5,8; pi. 3

Donax, 8 

tumida, Mysella, 9

(Rochefortia), 5, 9; pi. 7

Tellimya, 9 

turrita, Loxotrema, 26

Umpqua Group, 20, 21 

uvasana, Corbula, 6 

Kellia, 5, 6,7; pi. 3

vallecitosensis, Glyptoactis (Venericor), 18 

Megacardita (Venericor), 25

(Pacificor), 25

(Venericor), 17, 25; pi. 2 

Venericardia, 4, 76, 17, 18 

acuticostata, 28 

argentea, 19 

barbarensis, 13, 15 

borealis, 13 

c/arfc, 22, 23 

(Cyclocardia)

alaskana, 14, 39

californica, 13 

domenginica, 27, 28 

«aft6i,22,23 

(Gfyptoac/is)

domenginica, 27

keenae, 27

marfcri, 27

mcmastersi, 26 

(Gfypfoacfis?)

domenginica, 27 

/wrn/i,20,21,22,23

calafia, 21,22

c/arfa',22,23

lutmani, 20, 21 

ionensis, 23, 25 

joaquinensis, 24, 25 

(Leuroactis)

alisoensis, 23, 36

joaquinensis, 23

popenoei, 24

schencti, 23; pi. 6

anifeyi, 23

votes/, 23 

lutmani, 20, 22 

/warfcw, 27 

megastropha, 12 

montereyana, 13 

mulleri, 19 

(Paci/jcor)

aragonia

aragonia, 1 8, 24 

diabloensis, 17, 18, 20; pL 5 

joaquinensis, 17, 18, 23; pk. 6, 8, 9

argentea, 27; pi. 8

ca2a/ia 21

calafia, 17, 18,27;pL3 

gafcW, 17, 18, 22; pi. 4 

lutmani, 17, 18, 20; pis. 2, 4, 5 

susanaensis, 17, 18, 79; pi. 1

c/ar/b'

c/artt, 17, 18, 22; pi. 5 

popenoei, 17, 18, 24; pi. 9

crescentensis, 18

diabloensis, 20; pi. 2

durhami, 20; pi. 2

gabfc/,22

hertleini, 21;pL3

Aorn//, 17, 18, 22, 23; pi. 5 

carlosensis, pi. 2 

lutmani, 20 

susanaensis, 19

tea, 22, 23, 24

lutmani, 20

ww/teri, 17, 18, 79; pi. 1

nelsoni, 17, 18; pi. 1

oregonensis, 21, pi. 1

popenoei, 25

smiley i, pis. 6, 9

susanaensis, 19

taliaferroi, 1, 77, 18; pi. 5

transversaria, 19

vallecitosensis, 25

vokesi, pis. 8, 9

weaveri ; 22, pi. 5 

planicosta, 22

Aor/uV, 22

venturensis, 19, 25 

popenoei, 25 

sandiegoensis, 26 

(Venericor)

carlosensis, 25

Apr/u'i, 23

simiana, 25, 38

vallecitosensis, 17, 25; pL 2

venturensis, 17, 25; pL 8 

ventricosa, 13, 14 

venturensis, 17, 25 

weaver/, 23 

yatesi, 16 

nelsoni, 19 

Venericardinae, 16 

Venericor, 17, 18,25 

(Venericor) 

Glyptoactis

vallecitosensis, 18

venturensis, 18 

Megacardita

aragonia smileyi, 23

carlosensis, 25 

joaquinensis, 23 

vallecitosensis, 25 

Venericardia 

carlosensis, 25 

Apr/u'i, 23 

simiana, 25, 38 

vallecitosensis, 17, 25; pi. 2 

venturensis, 17, 25; pi. 8 

veneriformis, Cardita, 16 

"Cardita," 16

G/a/w (Centrocardita), 12, 7<5; pi. 7 

ventricosa, Cardita, 14 

Cyclocardia, 14

(Cyclocardia), 12, 74; pL 9 

Venericardia, 13, 14 

venturensis, Glyptoactis (Venericor), 18 

Venericardia, 17, 25 

planicosta, 19, 25 

(Venericor), 17, 25; pi. 8 

Verastegui, Pedro, cited, 27

quoted, 27

Yokes, H.E., quoted, 26 

vokesi, Venericardia (Leuroactis), 23 

(Pacificor); pis. 8, 9

W

Waring, C.A., cited, 11 

weaveri, Venericardia, 23

(Pacificor), 22; pL 5 

Woodring,W.P., cited, 13 

quoted, 15

yatesi, Venericardia, 16 

Yonge,C.M.,cited,4,7,15

PLATES 1-9

[Contact photographs of the plates in this report are available, at cost, from the U.S. Geological Survey Library, Federal Center,

Denver, Colorado 80225]
PLATE 1

FIGURES 1, 5, 11. Venericardia (Pacificor) mulleri Verastegui (p. E19).

Holotype CAS/SU 7994. Base of Lodo Formation, California. Paleocene. 

2, 4. Lasaea subviridis Ball (p. E6).

GAS 043249 (x7.3). San Diego, California. Holocene. 

3, 20. Venericardia (Pacificor) nelsoni Verastegui (p. E19).

Holotype UCMP 32804. Santa Susana Formation of Zinsmeister (1983),

California. Paleocene. 

6, 8-10, 12, 13. Aligena (Aligena) diegoana Hertlein and Grant (p. E7).

6, 8. Paratype LACMP 4548 (x4.5). San Diego Formation, California.

Pliocene. 

9, 10. Holotype LACMP 4547 (x3.0). San Diego Formation, California.

Pliocene. 

12, 13. Paratype LACMP 4551 (x4.5). San Diego Formation, California.

Pliocene. 

7. Kellia catacta Anderson and GD. Hanna (p. E6).

Holotype GAS 275 (x3.0). Tejon Formation, California. Eocene.

14. 16-18. Venericardia (Pacificor) calafia susanaensis Verastegui (p. E19).

Holotype CAS/SU 8004. Santa Susana Shale of Verastegui (1953), California. Eocene.

15. 19, 21. Glyptoactis (Claibornicardid) sandiegoensis (Hanna) (p. E26).

15, 21. Syntype UCMP 30982 (latex). Rose Canyon Shale of Hanna

(1927), California. Eocene.

19. Syntype UCMP 30980, latex, impression. Rose Canyon Shale, 

of Hanna (1927), California. Eocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 1

19

VENERICARDIA, LASAEA, ALIGENA, KELLIA, GLYPTOACTIS
PLATE 2

FIGURES 1, 2. Venericardia (Pacificor) calafia lutmani Turner (p. E20).

Holotype of Venericardia (Pacificor) durhami Verastegui CAS/SU 8005.

Juncal Formation, California. Eocene. 

3-5, 7. Venericardia (Venericor) vallecitosensis (Vokes) (p. E25).

3, 4. Holotype of Venericardia (Pacificor) hornii carlosensis Verastegui,

UCMP 15619. Domengine Formation, California. Eocene. 

5. Holotype UCMP 15614. Domengine Formation, California. Eocene.

7. Paratype UCMP 15615. Domengine Formation, California. Eocene. 

8, 9. Venericardia (Pacificor) aragonia diabloensis Verastegui (p. E20).

8. Paratype UCMP 32799. Meganos Formation, California. Paleocene 

and Eocene.

9. Holotype CAS/SU 411. Meganos Formation, California. Paleocene 

and Eocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 2

VENER/CARD/A
PLATES

FIGURES 1-7, 11, 16, 19. Venericardia (Pacificor) calafia calafia Stewart (p. E21).

1, 2, 5, 6. Hypotype GAS 8017 (xO.8) (Verastegui, 1953, pi. 16, 

figs. 2, 3;pl. 17, figs. 1, la, 2, 2a). Llajas Formation, 

California. Eocene. 

3, 4. Holotype UCMP 31450. Llajas Formation, California.

Eocene.

7, 16. Holotype of Venericardia (Pacificor) oregonensis 

Verastegui, CAS/SU 8009. Umpqua Formation, Oregon. Eocene.

11, 19. Holotype of Venericardia (Pacificor) hertleini 

Verastegui, UCMP 30415. Rose Canyon Shale of 

Hanna (1927), California. Eocene. 

8. Kellia lajollaensis Hanna (p. E6).

Holotype UCMP 31036. Rose Canyon Shale of Hanna (1927), 

California. Eocene.

9. 12. Kellia uvasana (Dickerson) (p. E6).

9. Holotype CAS 276. Tejon Formation, California.

Eocene.

12. Hypotype CAS 894 (Anderson and GD. Hanna, 1925, 

pi. 9, fig. 11). Tejon Formation, California. Eocene.

10. 15. Kellia laperousii (Deshayes) (p. E7).

Hypotype LACMP 4623 (Hertlein and Grant, 1972, pi. 44, 

figs. 11, 19) (x7.0). San Diego Formation, California. Pliocene. 

13, 14. Bornia (Temblornia) frankiana Hertlein and Grant (p. E8).

Holotype LACMP 4624 (x3.0). San Diego Formation, California.

Pliocene.

17, 18. Bornia (Temblorniana) triangulata (Anderson and Martin) (p. E8). 

Holotype CAS 130 (x3.0). Round Mountain Silt, California. 

Miocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 3

16

VENERICARDIA, KELLIA, BORN/A
PLATE 4

FIGURES 1, 12, 13. Venericardia (Pacificor) calafia lutmani Turner (p. E20).

1. 12. Holotype UCMP 33133. Umpqua Formation, Oregon. Eocene.

13. Hypotype UCMP 33009. 

2, 6, 8, 10. Venericardia (Pacificor) calafia gabbi Verastegui (p. E22).

2. 10. Holotype CAS 686 (xO.8). Tejon Formation, California.

Eocene. 

6, 8. Hypotype CAS 685 (xO.8) (M.A. Hanna, 1925, pi. 39, fig. 1).

Tejon Formation, California. Eocene. 

3, 4. Thecodonta (Pristes) oblongus (Carpenter) (p. E9).

Hypotype LACMP 4630 (x7.0) (Hertlein and Grant, 1972, pi. 44,

figs. 9, 13). San Diego Formation, California. Pliocene. 

5, 7. Neaeromya (Orbitella) compressa (Ball) (p. E10).

Hypotype of Roth (1979). Lower part of the Rio Dell Formation, California. Pliocene. 

9, 11. Cardita (Cardita) superioris Waring (p. Ell).

Holotype CAS/SU 143. Llajas Formation, California. Eocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 4

12

VENERICARDIA, THECODONTA, NEAEROMYA, CARDITA
PLATE 5

FIGURES 1. Venericardia (Pacificor) calafia lutmani Turner (p. E20).

Hypotype UCMP 33009. Juncal Formation, California. Eocene. 

2, 5. Venericardia (Pacificor) aragonia diabloensis Verastegui (p. E20).

2. Paratype UCMP 32799. Meganos Formation, California. Paleocene and Eocene. 

5. Holotype CAS/SU 411. Meganos Formation, California. Paleocene

and Eocene.

3, 7, 8. Venericardia (Pacificor) taliaferroi Verastegui (p. El7). 

3, 7. Hypotype CAS 7997.

8. Holotype CAS/SU 7996 (x2.0). Dip Creek Formation of

Verastegui (1953), California. Cretaceous and Paleocene. 

4, 6. Venericardia (Pacificor) clarki clarki Weaver and Palmer (p. E22).

Holotype of Venericardia (Pacificor) weaveri Verastegui CAS/SU 8024.

Cowlitz Formation, Washington. Eocene. 

9, 15. Cyclocardia (Cyclocardia) barbarensis (Stearns) (p. E15).

Lectotype USNM 104045 (x2.0). Santa Barbara, California. Holocene. 

10, 11. Glans (Glans) subquadrata (Carpenter) (p. E15).

Hypotype LACMP 4539 (x3.5). San Diego Formation, California. Pliocene. 

12-14, 16. Miodontiscus prolongatus (Carpenter) (p. E16).

12. 16. Hypotype LACMP 4544 (x3.0). San Diego Formation, California. 

Pliocene.

13. 14. Hypotype LACMP 4541 (x3.0). San Diego Formation, California.

Pliocene. 

17, 18. Venericardia (Pacificor) hornii (Gabb) (p. E23).

Lectotype ANSP 4558. Tejon Formation, California. Eocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 5

17

VENERICARDIA, CYCLOCARDIA, CLANS, MIODONTISCUS
PLATE 6

FIGURES 1-10. Venericardia (Pacificor) aragonia joaguinensis (Vokes) (p. E23).

1. 9. Hypotype UCMP 15615 (xO.8). Avenal Sandstone, California. 

Eocene.

2. 8. Holotype of Venericardia (Leuroactis) alisoensis Verastegui UCMP

30176. Llajas Formation, California. Eocene. 

3, 10. Paratype UCMP 15617 (xO.8). Avenal Sandstone, California.

Eocene.

4, 6. Holotype of Venericardia (Leuroactis) schencki Verastegui, CAS/SU 

8003. Santa Susana Formation of Verastegui (1953), California. 

Eocene. 

5. Holotype of Venericardia (Pacificor) smileyi (Vokes) UCMP 15626.

Domengine Formation, California. Eocene.

7. Paratype of Venericardia (Pacificor) smileyi (Vokes) UCMP 15627. 

Domengine Formation, California. Eocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 6

VENERICARDIA
PLATE 7

FIGURES 1, 2, 11, 14. Cardita (Strophocardia) megastropha (Gray) (p. E12).

1. 14. Hypotype (Durham, 1950, pi. 16, figs. 6, 11). UCMP 

30517. Unnamed Pleistocene strata, Baja California 

Sur.

2. 11. Hypotype UCMP 30518 (Durham, 1950). Unnamed

Pleistocene strata, Baja California Sur. 

3, 4. Cyclocardia (Cyclocardia) californica (Dall) (p. E13).

Holotype USNM 164558 (xl.5). Santa Barbara Formation, California. Pliocene and Pleistocene. 

5, 6. Mysella (Rochefortia) tumida (Carpenter) (p. E9).

Hypotype LACMP 4625. San Diego, California. Pliocene. (Photocopy of Hertlein and Grant, 1972, pi. 44, figs. 2, 4.) 

7-9. Glans (Centrocardita) veneriformis (Gabb) (p. E16).

7, 8. Holotype ANSP 4381 (x2.0). Martinez(?) Formation,

California. Paleocene(?). 

9. Paratype ANSP 4381a (x2.0). Martinez(?) Formation,

California. Paleocene. 

10, 12, 13, 16, 18, 20. Glyptoactis (Claibornicardia) domenginica (Yokes) (p. E27).

10, 18. Paratype UCMP 15613 (x2.0). Domengine Formation,

California. Eocene 

12, 16, 20. Paratype UCMP 15612 (x2.0). Domengine Formation,

California. Eocene. 

13. Holotype UCMP 15611 (xl.5). Domengine Formation,

California. Eocene. 

15, 22. Glyptoactis (Claibornicardia) sandiegoensis (MA. Hanna) (p. E26).

Holotype of Glyptoactis (Claibornicardia) mcmastersi Verastegui

CAS 8011 (x2.0). La Jolla Group, California. Eocene. 

17, 19. Glyptoactis (Claibornicardia) marksi Verastegui (p. E27).

Holotype CAS/SU 8021. Live Oak Member of Verastegui (1953),

Tejon Formation, California. Eocene. 

21. Cyclocardia (Cyclocardia) montereyana (Arnold) (p. E13).

Holotype USNM 165464. Monterey Shale, California. Miocene. 

23, 24. Cyclocardia (Cyclocardia) crebricostata (Krause) (p. E14).

23. Lectotype Museum der Humboldt-Universitat, Berlin 

37934 (Coan, 1977) (x2.0). St. Paul Island, Bering 

Sea, Alaska. Holocene.

24. Lectoparatype Museum der Humboldt-Universitat, Berlin 379311.(Coan, 1977) (x2.0). St. Paul Island, 

Bering Sea, Alaska. Holocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 7

23

CARDITA, CYCLOCARDIA, MYSELLA, CLANS, GLYPTOACTIS
PLATES

FIGURES 1, 2, 4, 5, 7, 9, 11, 14. Venericardia (Venericor) venturensis Waring (p. E25).

1, 9. Hypotype CAS 319. Santa Susana Formation,

California. Paleocene.

2, 11. Paratype of Venericardia (Venericor) simiana 

Verastegui CAS 8002. Santa Susana Formation, California. Paleocene.

4. Hypotype CAS 318. Santa Susana Formation, of 

Zinsmeister (1983), California. Paleocene.

5. 14. Holotype of Venericardia (Venericor) simiana 

Verastegui CAS/SU 8001. Santa Susana Formation, California. Paleocene. 

7. Holotype CAS 159. Santa Susana Formation,

California. Paleocene.

3. Venericardia (Pacificor) aragonia joaquinensis (Vokes) (p. E23). 

Paratype of Venericardia (Pacificor) vokesi Verastegui

CAS/SU 8016. Avenal Sandstone, California. Eocene. 

6, 8, 10, 12, 13, 15. Glyptoactis (Claibornicardia) keenae (Verastegui) (p. E27).

6. 15. Holotype of Venericardia (Pacificor) argentea 

Verastegui CAS/SU 7995. Base of Lodo Formation, California. Paleocene.

8, 13. Hypotype UCMP 33001 (xl.5). 

10, 12. Holotype CAS/SU 7992. Base of Lodo Formation, California. Paleocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 8

1 '.

13

VENERICARDIA, GLYPTOACTIS
PLATE 9

FIGURES 1, 2. Cyclocardia (Cyclocardia) crebricostata (Krause) (p. E14).

Holotype of Venericardia (Cyclocardia) alaskana Dall USNM 109271

(xl.5). Bering Sea, Alaska. Holocene. 

3-6. Cyclocardia (Cyclocardia) occidentalis (Conrad) (p. E13).

3. 5. Hypotypes UCLA 48619 (xl.5) (Hertlein and Grant, 1972). San 

Diego Formation, California. Pliocene.

4. 6. Hypotypes UCLA 48616 (xl.5). San Diego Formation, California. Pliocene.

7. 15. Venericardia (Pacificor) clarki popenoei Verastegui (p. E24).

Holotype UCMP 15689. "Coldwater" Formation, of Verastegui (1953), 

California. Eocene. (Photocopy of Verastegui, 1953, pi. 21, figs. 1, 2.)

8. 14. Basterotia (Basterotella) hertleini Durham (p. E10).

Holotype UCMP 32274 (x3.0). Comondu Formation, Baja California 

Sur. Pliocene.

9. 10. Cyclocardia (Cyclocardia) ventricosa (Gould) (p. E14).

Hypotype LACMP 4537 (xl.5) (Hertlein and Grant, 1972, pi. 43,

figs. 3, 8). San Diego Formation, California. Pliocene. 

11, 13. Cardita (Byssomera) affinis Sowerby (p. Ell).

Hypotype UCMP 30626. Unnamed Pleistocene strata on Isla Carmen,

Baja California Sur. 

12. Cyclocardia (Cyclocardia) kirkerensis (Clark) (p. E12).

Holotype UCMP 11165 (x2.0). Kirker Tuff, California. Oligocene.

16. 18. Milneria minima (Dall) (p. E28).

Hypotype LACMP 4546 (x7.0). (Hertlein and Grant, 1972, pi. 43, 

figs. 1, 2, 14) San Diego Formation, California. Pliocene.

17. 19. Venericardia (Pacificor) aragonia joaguinensis (Vokes) (p. E23).

17. Holotype of Venericardia (Pacificor) smileyi (Vokes) UCMP

15626. Domengine Formation, California. Eocene. 

19. Paratype of Venericardia (Pacificor) vokesi Verastegui CAS/SU 

8016. Avenal Sandstone, California. Eocene.
U.S. GEOLOGICAL SURVEY PROFESSIONAL PAPER 1228-E PLATE 9

17

CYCLOCARDIA, VENERICARDIA, BASTEROTIA, CARDITA, MILNERIA



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